NBSIR 83-2724

Swiss Research in Building

Heating Conservation

id for QC —

1 pvQ re and Hybrid Solar

y Division

. U56 ; of Solar Heating Technology

83-272/Pe P artment °f Energy

1933 ington, DC 20585

Swiss National Energy

Research Fund, NEFF

Basel, Switzerland

NBSIR 83-2724

SWISS RESEARCH IN BUILDING

HEATING CONSERVATION

S. Robert Hastings 1 2 Roger C. Ruggli 1

formerly

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Washington, DC 20234

USA.

’Building Physics Group

Swiss Federal Laboratories

for Materials Testing

CH 8600 Dubendorf

Switzerland

June 1 983

Prepared for Passive and Hybrid Solar

Energy Division

Office of Solar Heating Technology

U.S. Department of Energy

Washington, DC 20585

Swiss National Energy

Research Fund, NEFF

Basel, Switzerland

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

ABSTRACT

Swiss research on heating energy conservation in buildings is presented

to encourage communication among researchers. A background on Switzerland’s

climate, geography, construction industry, and energy situation is included

to provide a context for the subsequent review of a sample of research

projects. Each project is described with a statement of research objectives,

technical approach taken, project status, brief findings, future work planned

or recommended, and resulting publications. The sample of projects is taken

from the subjects of community scale solar concepts, mathematical simulation,

instrumented test cabins, instrumented buildings, and design tools and data

bases. The final section discusses a structure for surveying research

projects in a country in order to examine where efforts are now concentrated

and what subjects are not addressed. Swiss research is examined using this

structure and an assessment is presented.

iii
ACKNOWLEDGEMENTS

The preparation of this report has been co-sponsored by

the U.S. National Bureau of Standards (NBS) , Center for

Building Technology, with funding from the U.S. Department

of Energy (DoE) , Solar Cities and Towns Program; and the

Swiss Federal Laboratories for Materials Testing (EMPA)

with funding from the National Energy Research Fund

(NEFF)

The authors wish to thank the following individuals:

- Frank Deserio, DoE Solar Cities and Towns Program Leader.

Francis T. Ventre and Robert D. Dikkers of the Center for

Building Technology and the members of the NBS staff who

served as technical reviewers.

- R. Sagelsdorff, EMPA, Building Physics Group Leader, and

the EMPA technical reviewers

- W. Thut and M. Epprecht, Vice Presidents of NEFF.

Each of the reported project researchers.

Notice of Disclaimer

Commercial products are identified only for the sake of

completeness. Such identification does not constitute endorsement

by NBS or imply that they are necessarily the most suited.

iv
Conversion Factors

Length

1 centimeter (cm)

1 meter (m)

1 kilometer (km)

Area

2

1 square meter (m ) 2

1 square kilometer (km )

Volume

3

1 cubic meter (m ) 1 liter (A)

Mass

1 kilogram (kg)

Temperature

1 degree Celsius (°C,K)

Energy

1 kilojoule (kj)

Power

1 watt (W)

1 W/m2

1 W/m2

K

Monetary

1 SFr

0.3937 inches (in)

3.281 feet (ft)

0.62 miles

2 10.76 square feet (ft ) 0.386 square miles

35.33 cubic feet (ft^)

0.264 gallons

2.2 pounds (lb)

5/9 ( °F - 32)

0.948 Btu

3.412 Btu/h

0.317 Btu/ ft

2 h

0.176 Btu/ft 2 h °F

$0.50 (Dec. 82)

v
•' • V

• ...

vi
CONTENTS

INTRODUCTION 1

1 . BACKGROUND 3

2. PROJECTS 15

Concept Development

2.1 A Community Wood/Solar District Heating System 17

2.2 Settlement pattern and heating optimization 23

Mathematical Simulation

2.3 DOE 2. Implementation and Validation 31

2.4 DEROB Implementation and Validation 37

Test Cabin Measurement

2.5 STESO Test Cabins 43

2.6 Solar Trap 47

2.7 Maugwil Test Cabins 55

Instrumented Building Measurement

2.8 Three passive solar houses 65

2.9 An attached greenhouse near Zug 75

2.10 Limmatstrasse Apartment Building Retrofit 81

2.11 Chaumiere Apartment Building 93

2.12 Zug Apartment Building 97

2.13 LESO Office Lab Building 101

Design Tool and Data Development

2.14 Automated Climate Data Collection Net 105

2.15 Occupant Factor/Air Change Rate Data Base 109

2.16 Impulse Program: Component Testing Data Base 123

2.17 A Simplified Method for Calculating Heating Demand 127

3. OBSERVATIONS 135

vii
-

.
- 1 -

INTRODUCTION

Switzerland and the United States share many common problems in reducing energy consumption. To a certain extent, the problems in Switzerland are magnified relative to the U.S. All oil consumed in Switzerland

must be imported and a higher than average price per barrel must be paid.

This report focuses on Swiss research to reduce energy consumption of

buildings through conservation and passive solar energy use. Emphasis is

given to research on the building envelope and how it responds to the

ambient climate relative to the desired controlled interior environment.

Figure 1 illustrates this relationship.

Fig. 1 Climate, Building Envelope, Interior Environment

Interaction
- 2

-

This report draws upon two research status seminars:

An energy conservation research seminar (1) convened by EMPA provided a broad cross section of the majority of the projects dealing with conservation, and a similar seminar (2) convened by the Swiss Federal Institute

of Technology in Lausanne (EPFL) provided a cross section of solar re- search projects. For selected projects additional documentation was then collected, and as time permitted, the individual researchers were

contacted.

This report begins with a background to provide a context for building

conservation research. Briefly discussed are the Swiss climate, terrain, regulations, financing, and construction philosophy. Also covered

are gross statistics on national energy uses and sources, Swiss building research funds and institutions, and research coordination.

The body of the report presents a sample of projects involving building components, systems, and supporting research. The projects have

been grouped by research approach as follows: concept generation, mathematical simulations, test cells, instrumented buildings, and design

tools and data. Each project review consists of a statement of background, objectives, approach, status, example results, comments by the

authors, and publications.

In the final section of the report the authors identify in what research

areas Switzerland has concentrated and what future directions Switzerland may take in the field of building heating conservation research.

(1) EMPA, Schweizerisches Status Seminar: Warmeschutz-Forschung im

Hochbau, Abteilung Bauphysik, CH 8600 Diibendorf, October 1980

(2) Symposium: sur la recherche et le developpement en energie so- laire en Suisse , Dept, of Physique, Groupe de Recherche en Energie

Solaire, Swiss Federal Institute of Technology, CH 1001 Lausanne,

Oct. 1980
- 3

-

To better consider Swiss building

heating conservation research it is

important to understand the con- straints and opportunities in Switzerland. This section provides a brief

background on Swiss climate, terrain,

population densities and distribution,

regulations, financing, construction

philosophy, and energy sources and

uses. Also included are a background

of major research sponsors and institutions .

.

BACKGROUND
-4-

Climate

Switzerland can be divided into three main climatic zones. Zone 1 has a raiddle-European climate, Zone 2 has a Mediterranean climate, and Zone 3

has an alpine climate. Heating degree days (US ASHRAE °F method) for a city

in each of the three zones are shown on the map in Figure 2.

There are pronounced local climate differences within each climate zone. Differences in solar radiation result from regional patterns of cloud cover and also from regional shadowing by mountains. Figure 3a illustrates the actual number of hours of sunlight (the white length of the

bars) relative to the total possible at that latitude (the total length

of the bars). The width of the bars indicates the curtailment of sun- light due to shadowing by the mountains, a narrow bar indicating extensive shadowing. Figure 3b graphs the global and diffuse solar radiation

for Zurich (Kloten) , Davos and Locarno in comparison to Boston and Albuquerque .
- 5

-

Percent actual relative to possible sunshine h/month

o ) 0 %t

b) Possible sunshine h/month due

to day length (100s of hours) Considering shadowing by alps

i » « > < ihoun

I I I I 'DM

20°, o 30°.'o 40°/« 50°'-

Regional sunshine duration as

Fig. 3a Dec. Average Sunshine Duration percentage of possible
- 6

-

Terrain-Population

Switzerland has a total land area of 41,293 km2 which is about twice the

size of New Jersey or a tenth the size of California. The population

density is three tiroes greater than in California and 40 percent that of

New Jersey.

Land uses can be divided as follows:

Unusable^

Built- up-—

Vl6% 27%\— Forest

Water—

'

Pasture -- X-21% / 28%-/— Cropland

Fig. 4 Land Use in Switzerland

Most of the population live in the midlands between the Jura and the

Alps (climate zone 1) at an elevation between 400 and 600 m. This is

the main useable land zone and of course the main building zone as well. Concentrations of population are indicated by dark areas on the

following map.

Fig. 5 Population Distribution in Switzerland
-7-

Regulation

Contemporary Swiss building patterns are strongly influenced by local

regulations and can be quite different in each municipality (the lowest

governing body) . Regulations are quite detailed and determine parameters

such as building height and size, roof form, colors, U-values, number of

parking spaces, setback distances, amount and size of windows per m

2 of

floor area, ceiling height etc. Safety regulations are similar in all of

Switzerland. Example parameters include: fire regulations, heights of

balustrades, width of staircases etc.

Other important factors influencing building come from the federal planing law, which is applied by each Canton (State). Those laws are mainly

zoning regulations specifying allowable land uses for designated areas,

(e.g. single family, multifamily, commercial, industrial).

The major difference between land use regulation in Switzerland and in

the U.S. is that in Switzerland regulation has largely confined building

to within built areas with a defined boundary. By contrast, in the U.S.

building tends not to be confined but to scatter beyond the boundaries

of a built-up area.

Effective land use regulation is possible in Switzerland because there

is no inherent right to develop land. Therefore, open space can be

preserved without the inordinate expense of compensating land owners. The result of this policy is extensive tracts of forest and farmland

immediately adjacent to tightly defined dense urban areas.

Financing

The price of land in Switzerland is extremely high. At the moment land

2 prices in U.S. dollars vary from $ 75 to $ 250 /m for residential lots

in outlying towns. (City residential lots are of course much higher).
Construction coats for s small house begin at $ 175,000. Including the

cost of a minimal lot in an outlying town the total cost for a modest house is therefor seldom less than $ 250,000. Accordingly, the

great majority of the population live in apartments.

Such prices are only conceivable for the few people who do buy houses

because of the financing mechanisms available in Switzerland. A 20 percent

downpayment is usually required by a bank. Sixty percent is then paid by the

bank in a first loan, typically at an interest rate between six and eight

percent. The bank provides the remaining 20 percent as a second loan at a rate 1/2 percent above the first loan. Both interest rates are variable.

The second loan is amortized over 15 years, the first loan is never paid

back and the monthly payments accordingly include no repayment of the

principal, only interest payments. This testifies to the fact that houses

in Switzerland are built for long term service.

Construction Philosophy

Longevity is a dominant characteristic of Swiss construction philosophy.

This manifests itself in the materials used: concrete, brick, roofing

tiles, copper flashing and rainwater conductors, etc.

The residence is considered a place of security. An underground bombshelter must be provided for each new dwelling. The shelter is a 40 cm thick, heavily reinforced concrete, enclosure with a concrete

vault door, and an air filtration system. Another residential design

feature is the attention given to preventing forced entry. Locks are built to be "impenetrable". This can be a disadvantage, however, in case of fire since locked doors are commonly impenetrable in either

direction without a key.
-9-

Background on Energy Use Patterns

Figures 6 a, b, and c illustrate sources, end uses, and end use forms

of energy. Noteworthy is the high percentage of total energy use which

comes from electricity, and the large percentage which nuclear energy

represents. Significant for solar energy use consideration is the fact

that 45 percent of Swiss end-use energy is used for heating at temperatures not exceeding 80°C. This low temperature heat demand is presently

being met by high temperature (e.g. 1000°C) sources (1).

Conservation and solar energy use can help reduce the excessive reliance

on high quality energy sources for low temperature end uses.

(1) Source: Bundesamt fur Energiewirtschaft , "Schweizerische Gesamtenergiestatistik", Bern, June 1981.
- 10 -

Building Research Sponsors (Public) and Institutions

The primary Swiss building energy research sponsor is the National

Energy Research Fund, NEFF. It was created in 1978 by a consortion of

Swiss Industries to support energy research in collaboration with the

federal government. In 1980 NEFF spent $ 5.5 million on research

projects of which half was spent on research in building energy conser- vation and alternative energy sources. (1)

Another major research fund is the National Fund (NF), a government institution which spent $ 4.5 million on energy research over the last

five years. The NF tends to finance socio-economic research in contrast

to the NEFF which tends to finance technical research.

A third research sponsor is the Commission for the Advancement of

Scientific Research (Bundesamt fiir Konjunkturfragen) , another government office which acts mainly as an intermediary between researchers

and interested industries. It co-finances only projects that are of

immediate interest to industry. Industry must co-finance at least 50

percent of a project's costs.

Figure 7 presents total energy research expenditures from all sources (2)

(1) NEFF, "Jahresbericht 1980", Nationaler Energie-Forschungs-Fond , Basel

(2) Bundesamt fiir Energiewirtschaft , Bern, June 1981.
- 11 -

Primary Building Research Institutions

EMPA Swiss Federal Laboratories for Materials Testing

Ueberlandstrasse 129

CH 8600 Dubendorf

At the EMPA the Applied Physics in Building section, under the

leadership of Mr. R. Sagelsdorff is mainly involved in research

in energy conservation, active and passive solar energy use and

basic building physics. The EMPA is an Annexe to the Swiss Federal Institute of Technology.

EIR Swiss Federal Institute for Reactor Research,

CH 5303 Wuerenlingen

The EIR is involved in testing heat pumps,

solar collectors, and photovoltaics

.

Contact: Dr. Kesselring
- 12 -

EPFL Swiss Federal Institute of Technology Lausanne

14, Av. de l'eglise anglaise

CH 1006 Lausanne

At the EPFL the Solar Energy Research Group, Theoretical

Physics Laboratories, under the leadership of Prof. A. Faist

is involved in test cell measurement, instrumented building

monitoring and computer simulation.

University of Geneva 32 Boulevard d'lvoy

CH 1211 Geneva

At the University of Geneva the Solar Energy Group under the

leadership of Prof. A. Giovannini is involved in assembling

a literature data base on technical developments and applications in the fields of energy conservation in buildings and

household appliances.

ETHZ Swiss Federal Institute of Technology, Zurich

Einsteinstrasse

CH 8049 Zurich

The ETHZ researches energy conservation and solar energy

through it's institutes:

HBF (Building research institute)

The HBF is involved in research application for

university teaching.

Contact : Prof H. Kunz

HBT (Institute for Building Techniques)

The HBT is involved in building related energy

conservation techniques.

Contact : Prof. H. Hauri
-13-

HTL Brugg-Windisch Klosterzelgstrasse

CH 5200 Brugg-Windisch

The HTL (Technical High-School) Brugg-Windisch is host

to INFOSOLAR, a solar literature reference center.

Contact : Mr. Thomas Fisch

ZTL (Technical Highschool of Central Switzerland)

6048 Horw

Contact : Mr. Hiisler
-14-

Energy Research Coordinatioa

International building energy research coordination in Switzerland is

principaly accomplished through the International Energy Agency (IEA).

Swiss contacts are: Dr. L. Dubai and Dr. G.Schriber, Federal Energy

Office in Bern (BEW) ; Dr. P. Hartmann, (EMPA); and Prof. A.Faist, (EPFL)

.

NEFF funded building energy conservation research is coordinated by a specially created coordination project, KWH, resident at EMPA. The project's function is to ensure information exchange among the numerous NEFF

funded projects at various institutions and private firms, and to provide NEFF with recommendations for future research directions.

INFOSOLAR, another NEFF funded project, is a documentation/information

resource center for commercial product literature in the subject area

of solar energy and energy conservation.

SIA, the Swiss Engineers and Architects Association, publishes standards

and documentation on all aspects of building construction. Several

reports on energy conservation have been published. A background publication on solar energy use in buildings was published in 1982 (SIA 380.5).

SITI, the Swiss Institute for Technical Information provides literature

research for any institution or individual on any technical subject.

Searches are done using a computer system, and through telephone con- nection to more than 100 international data-banks.

Research coordination is also done by the "Schulrat", the highest

administrative organ of the Federal Institutes of Technology. This

organ coordinates research at the ETHZ, EPFL, EMPA, and EIR.
-15-

The following research projects provide a sample of work ongoing or re- cently completed in Switzerland.

For each project a brief background

summary is provided followed by a statement of objectives, approach,

status, example results, and publications. The number of projects

selected in each general area re- flects the authors' perception of

the extent of activity in that

general area. The reported status

reflects the status as of August

1981. The publications listed are those available from the given project up to that date.

PROJECTS
- 16 -

'
-17-

2.1 A COMMUNITY WOOD/SOLAR DISTRICT HEATING SYSTEM

BACKGROUND

A complex wood/ solar district heating system has been designed for Sent,

a small mountain community of approximately 400 dwelling units. The system

design is as follows: The heat from solar collectors is extracted by heat

pump evaporator elements configured as the solar absorbing surface. The

heat pumps are powered by internal combustion engines. These engines are fueled by gas from wood gasification units. The heat from the heat pumps

is distributed in a pipe network to the individual residences. The design

is now in the pre-bid stage. J. Buchli and J. Studach of the engineering

firm of IGEK are the project leaders.
-18-

1. Objectives

- Efficient use of solar and wood energy as heat sources for space and

domestic water heating at a community scale.

- Efficient distribution of heat at low temperatures with minimal transmission losses and direct use of the delivered heat at the individual

terminals

- Achieve economic efficiency considering both capital and operating costs.

2. Approach

A wood gasification system was determined to be a valuable approach to

supplying heat to a central system because it permits the more efficient

combustion of waste wood, e.g. branches, bark, chips. The wood gas is

used to fuel internal combustion engines which drive solar assisted heat

pumps. The solar assistance is accomplished by the heat pump evaporator

elements which are treated with a black varnish and comprise the absorber surface of solar collectors. Distribution of heat from the heat

pumps is accomplished with a bundled four pipe system consisting of

supply and return water pipes for space heating and for domestic water.

The domestic hot water is used directly from the copper piping without

a heat exchanger at the terminals. A single mantel of insulation

encases the four pipes. Each terminal has a flow meter but no calorimeter for measuring heat extraction. This favors users with a total or partial low temperature heating system (e.g. radiant floors) which ex- tracts the maximum heat from the water. The result is increased capacity

of the distribution system and more efficient use of the heat pumps. The

following plan illustrates the layout of the central heating plant and

the distribution system with the location of the central plant in the

community.
-19

; J

Solar collection roof 150m2

Heat pump room

Wood gas generator room

Wood storage

4000m3

Wood gas generators

line capacity 230 KW

Water reservoir

Gas engines 50 KW at 1500 rpm

Heat pumps 100 KW

4 P I

Fig. 8a Plan and Cross Section of the Central Heating Plan

Wood storage

C> -

Fig. 8b Map of Sent Distribution Lines
- 20 -

3. Status

The design of the system has been completed and approved in principle

by the town and the sponsors (the National Energy Research Fund, the

Bank of the Canton of Graubiinden and the Community of Sent). The

engineers are now in a pre-bid discussion phase with selected

contractors

.

4. Example Results

The calculated benefit of the system is based on several assumptions:'

The existing energy sources and their proportion of useage are:

- wood,

- fuel oil,

- electricity,

21 %

75 % (522,700 £

4 %

(5,280 GJ/yr)

= 18,440 GJ/yr)

(1,040 GJ/yr )

total 24,760 GJ/yr)

The number of occupied buildings varies substantially by season with

occupancy peaks of 100 percent occurring in July and August and of

90 percent in February and March. Minimum occupancies of 60 percent

occur in November and May.

The energy consumption of the community is expected to increase

between now and the year 2000 as a result of the addition of residences

to the present inventory, and as a result of an expected increase in the

percentage of dwellings occupied the entire year.

Using these assumptions, a computer model was run to project heating

energy use if no steps were taken, if conservation measures were applied,

and if conservation along with the proposed heating system were implemented. Figure 9 graphs these three options.
- 21 -

Fig. 9 Annual Heating Requirements for Three Options
- 22 -

By the year 2000 it is estimated that 80 percent of the dwellings would

be connected to the district heating system. Investment costs for the

system are estimated at $ 3,850,000 to serve the resulting demand. While

such costs are relatively high, the designers expected that a community

also would place a value on local energy self-sufficiency and that distributed hot water for space heating or domestic hot water will be deemed as much a required part of a town infrastructure as the water supply and sewer network.

5 . Comments

A heating system as complex as this may be more efficient than one might

at first expect. First, one might ask, "why not burn the wood in each

individual home, eliminating the distribution losses?" The proposed

system may be more desirable because it can burn waste wood products

efficiently and with air pollution control. One might then ask,

"given the benefit of wood gasification, wouldn't it be logical to

merely distribute the gas to each dwelling for combustion on site?"

This alternative precludes the gains from the solar assisted heat pumps.

One might finally ask, "why not collect the solar energy at each house

since the sun is already a distributed resource?" This alternative is

not desired because of the adverse impact on the overall aesthetics of

this old mountain village were 80 percent of the houses to be retrofitted with solar collectors. A central system with a buried distribution

net minimizes the visual change imposed on the community.

Publications

Buchli, J. and Studach, J. , Warmeversorgung Sent , IGEK Engineers,

Hegisplatz 6, 7000 Chur, Switzerland, June 1980
- 23 -

CT ! ein- meurfamilienhaussiedlung O 1 1 NIEDRIGER DICHTE WDFD

D D D D D

D D 0 D

D D D D D

D D D D D

D D D D D

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

ST 2

DORFKERN UN) EINFAMILIENHAUSSIEDLUNC)

HOHER OICHTE DO C DyCgGjQ

|G!o

CITYBEBAUUNG AB MITTE 19. JAHRHUN)ERT r\j-, / i

r\ pmi r~ (5 Hi 1

(j~ i J t l

2.2 SETTLEMENT PATTERN AND HEATING OPTIMIZATION

BACKGROUND

The implications of the physical characteristics of urban structure

on space heating has been researched in the Federal Republic of Germany

since the mid seventies. As the result of a competition the Swiss con- sulting firm 'UR' of Ueli Roth (ZUrich) was awarded the project described here. Heating systems of various types and scales were evaluated

for their economic and energy performance potential for given configurations of settlements. Domestic water heating as well as space heating

were considered.
-24-

1. Objectives

- Devise an analytical procedure for minimizing space heating and water

heating costs (including conservation investment and operating costs)

given the implications of specified settlement structures.

- Assess individual consumer goals and their compatibility with regional

energy goals.

2. Approach

A cost benefit analysis method was used to analyze various combinations

of residential settlement patterns and heat supply systems. Each such

combination was analyzed relative to conservation (insulation) investment

costs and respective heat supply costs (energy, operation, maintenance,

and capital). Figure 10 illustrates the principle of determining a total

cost minimum.

Annual cost

Fig. 10 Total Cost Minimization

Heat load
-25-

The approach to the project had four steps:

1 . Definition of various building and settlement configurations

(including both present and possible future configurations).

2. Cost analyses of various heating conservations options.

3. Cost analyses of various heat supply systems.

4. Evaluation of various heat supply systems relative to items 1, 2,

and 3 above.

Each of these steps will now be discussed.

1 . Settlement pattern

Nine settlement types were defined as bases for the calculations.

The types were derived in consideration of several (unstated) data

bases for German cities and towns.

2. Heat conservation in buildings

Heat conservation is often capital intensive. A major issue is therefore

how to use available capital with maximal efficiency. First the costbenefit characteristics of a single conservation alternative have to

be represented. Two main conservation alternatives considered were:

a) Insulation improvement for the nontransparent parts of the shell

(walls, roofs, etc.)

b) Window improvements.

A representative catalogue of heat conservation alternatives was assembled to show their cost relative to gained insulative values.

Economically optimal solutions were identified from various combinations

of measures.

3. Heat supply systems

Twelve heating system types were compared. Their capital cost and

operational cost were evaluated relative to saved heat.
-26-

4. Evaluation of heat supply systems

The effectiveness of certain heating systems for given settlement

patterns can be evaluated based on average combined costs for heating

supply and conservation. Figure 11 illustrates a ranking of different

heat supply systems for different settlement patterns. The number of

dots indicates the goodness of the match between the heating system and

the settlement pattern.
27

Old Construction New Construction

Key

• Minimal match •• Good match ••• Excellent match

,

'I

Single

and

Multi

Family

Residential

Low

Density

2

Towns

and

Developments

-

Med.

Density

3

Row

House

Developments

4

Row

Neighborhood

-

Middle

Density

5

Row

Neighborhood

-

High

Rise

6

Open

Blocks

7

Mid

18

Century

City

Block

8

Middle

Ages

City

Block

9

Industry 1

Single

and

Multi

Family

3

Row

Houses

4

Row

Neighborhoods

-

Middle

Density

5

Row

Neighborhoods

-

High

Density

9

Industry

ST ST

2

ST

3

ST

4

ST

5

ST

6

ST

7

ST

8

ST

9

ST

1 ST3

ST

4

ST

5

ST

9

District Heating System • • «• 99 999 999 999 999 999 999 99 99 999 999 999

Annual Solar System 9 9

Solar Ast Central System • • 9 9 9 © 9 9 • 99 99 9 9 9

Wood Fired Boiler

Cogeneration System • • • •9 999

Gas Heat Pump • Gas Furnace

Oil Furnace • 90 9 9 © 9 9 9 9 9 999 9 9 9 9

Electric / Heat Storage 9 9 9 9

Heat Pump « 9 9 99 99 9 9 9 999 9 9 9 9

Oil / Solar • «

Biogas • 9 9 9 9 9 • 99 99 9 9

Fig. 11 Urban Structure versus Heating System Types
-28-

3.

Status

On grounds of this theoretical study the firm 'ur* has been asked by

the federal government to conduct several case studies in different

German towns. Regional heat supply concepts for Hamburg and for Mannheim/Heidelberg will be developed during the period of 1981 - 1983.

4. Example Results

The investment cost of economical heat conservation measures for new and

existing buildings would be circa $20 to 30 billion (1978 dollars) for

Germany over 20 - 30 years. With a 25 percent increase in heated floor

area the heat load could be decreased by 15 percent from the current heat

load by these measures.

The report stresses that a shift in investment from macrotechnological

energy supply systems to smaller scale retrofit conservation systems

is economical and ecologically more apropriate.

5 . Comments

The main achievement of the project is a classification and quantification of the interdependencies between urban structure and energy supply

systems. This approach could well be used in case studies. However, one should not perceive this report to be a guide for selecting a heating

system for a given settlement. In practice this decision will depend

on more variables than those included in the report's analysis, such as availability of a given system on the market or how secure the delivery

of a given fuel type will be in the future. Also, the scenarios for dif

ferent energy price developements were too limited. Oil prices have already exceeded the levels assumed in price escalation calculations.
-29-

A final comment must be made that passive use of solar energy could also

be treated as a means of energy supply in combination with conservation.

This has been treated only in a cursory manner.

6. Publications

1. Schweizerisches Status-Seminar "Warmeschutzfors chung im Hochbau”,

EMPA, 8600 Dubendorf, October 1980.

2. "The Impact of Settlement Patterns on Low Temperature Heating Supply

Systems, Transportation and Environment”,

Proceedings of the International Congress for Energy

Supply and Management, Tucson, Arizona, USA.

Pergamon Press, 1977.

3. "Wechselwirkung zwischen Siedlungsstruktur und Warmeverso rgungssystem” (mit F. Haubi). Schweizer Ingenieur und Architekt , Nr. 29/1980, SIA, 8039 Zurich.
- 30 -
-31-

2.3 DOE 2. IMPLEMENTATION AND VALIDATION

BACKGROUND

A building energy use computer model, DOE 2 (U.S. Dept of Energy) is being

validated for use in Switzerland by the EMPA. The work is being carried

out as part of the International Energy Agency (IEA) Program, "Energy Conservation in Buildings and Community Systems" (under Annexes I, III and IV).

Dr. J. Gass of EMPA is the project leader for a set of test runs using

DOE 2 : an English bank office building in Bristol (analyses completed)

;

an English commercial office building in Glasgow (in progress); a Swiss

single family house in Maugwil (in progress, see photo above); and a Swiss apartment building in Lausanne (in progress).
-32-

1. Objectives

- Evaluate a computer program, DOE 2, for analyzing the energy and

economic performance of buildings.

- Compare DOE 2 results with measured data from instrumented buildings.

- Customize DOE 2 for specific Swiss requirements (e.g. Swiss building

practices, HVAC equipment, and climate data format).

2. Approach

For those readers not familiar with the details of the program, a description follows. DOE 2 is a program which calculates the hour-by-hour

energy use of a building and its life-cycle cost of operation, given

information on the building’s location, construction, operation and

HVAC equipment.

The program has four main calculation sections:

Loads

Calculates hourly heating and cooling loads for each designated

space (thermal zones) within the building.

Systems

Simulates the operation of the heating and cooling distribution system, taking into account outside air requirements, operating

and control schedules, and building transient response when no heating or cooling is required.

Plant

Simulates the operation of primary energy conversion equipment.

The program models:

a) conventional central plants

b) solar heating and cooling systems

c) plants with on-site heat generation and waste heat recovery.

Monthly and annual costs are calculated.
- 33-

Economics: Calculates the present value of the life-cycle cost of the

building, including cost of fuel, equipment, operation and maintenance.

Input data

General:

Loads:

System:

Plant:

Economics:

include:

Building location, weather data.

Building orientation, dimensions, materials etc.

HVAC description.

Primary equipment.

First cost, replacement costs, annual costs for non

plant items.

Fig. 12 Doe 2 Computer Program Configuration
-34-

At the beginning of the project the only available long term hourly weather

data which included solar radiation data were from Zurich's Kloten airport

(8 years: 1964 - 1972). However, the Kloten climate is not typical for all

of Switzerland .The Swiss Meteorological Institute SMA began installation

of an automatic net of 60 weather stations (ANETZ) in 1978. As the ANETZ

hourly measurement computer files become available they will be the main

source for preparing DOE 2 weather files. However, the present two years

of data are not enough to produce a representative average year weather

file. In order to get reliable results on the life cycle energy cost

of buildings with DOE 2 the ANETZ data will have to be complemented by

long term weather data.

Another problem is obtaining direct normal radiation data, which is

currently not measured and has to be derived from global horizontal

radiation data.

3. Status

Following analyses of a hypothetical American office building in

a Swiss climate DOE 2 was tested on a bank building in Bristol,

England. The test on the Glasgow commercial building is in progress.

Selected Swiss climate data can now be entered in DOE 2. Analysis of

the Lausanne apartment block and comparison with measured date from

the building is now underway.

4. Example Results

The following table is output from a DOE analysis of the above mentioned

American office building modeled with Swiss climate data (Kloten). It is an open plan, single story building 15 x 30 m long, divided in the program

into five thermal zones. Windows are double glazed, walls have an insulation value of 0.4 W/m2

, and the roof and floor 0.3 W/m2

.
35

_o> -Q

,o

tnC

•H

T3

Elec

Maximum

Elec Load <kW)

O

CN

rpCN21. 21. 21. 21. 21. 21. 21. 21. 20. 20. 21.

ElectricalEnergy (kWh)

5.316. 4.739. 5.051. 5.158. 5.428. 4.856. 5.436. 5.251. 5.031. 5.377. 4.966. 5.145.

61.750.

CD o CO o in vo VO CD CN VO P cd ID rp m CD o CN r- O'* C* r- cn in 9 c 3J • B •h s r» o in CD o O VO cn VO on cn

•H

p TJ

O r- VO VO vo CD •—l

r* r"

X 03 03 Eh cn CN rp P P cn cn cn

ol 03

Q tt) £ 33

Cl, Cl, Cl, Cl, Cl. Cl, Cl, fc, Cl, Cl, Cl, 1 .Q ft

XJ rp E ID CN rp VO (N 00

n P o cn cn

(1)

G cn

m in VO VO cn cn 3 CQ Eh

CP Cl, Cl, Cl, Cl. Cl, fc, Cl, Cl, Cl, Cl, 1 XI a

cn »—

H

p in cn CN VO cn CD P P ^r vr

£7

G d) cn co in VO VO cn cn c a 03 Eh

•rH

4-> 03

X

03 & 03 P CD CD CD CD CDp CD o CD CD

•rH 6 p

0) Eh

33

p >1 CO in CN

p CN CD cc CD 0 'O rp rp CN CN CN CN P CN p

in CN CD •^T o m o P 00 CN cn

CD VO o Q

Q

pm in CN cn

C >1 CD rp VO rrn o 0 o o oo in cn

•H CD

p P P H cn cn i | o o o’ o o in CD 00

03 03

m in

03

C £

33W P §

cd 2 CN in o in

m VOp P p in in

03

G 33 o CN vo P CD CO VO o>

p 00

G S •P \ • 0 •3 rp -a p CN cO co CN vo* CN CD VO p c\ vO

•HX 0 03 P VO VO CD CD CD cn VO 00 VO CN CD PG

03 S 0u s s P CN CN CN CN

p CN

03>G0u ft Cl, Cl, Ct, Cl, Cl, ft Cl, ft Cl, Cl, I XI Q< u P rp § o CD cn CO VO m in VO a* 0 03 G •vr in VO vo vO vo in cn

4h 3 03 Eh u

03 cd £ Cl, Cl, Cl, Cl, Cl, Cl, Cl, Cl, Cl, Cl, Cl, Cl, g G 1 .Q ft 3 >H •—l E VQ CD in m cn o CD o in cn

CO •Hu

G aJ in in vo vo r- VO r* in in

a 03 Eh

(/) TO

rd 0 3 0 Q3

X E 03 P CD CO CD CD CD CD CD o^ CD vo CD o •rH a rp <—1 p p p P

£1

Eh

VG P >i

O r- CN in VO in CN CD r- r" 0^ 0 0 'G m CN CN P p P p s

4JC

?3 & m CD

Q

p r* CD CNm

Q CN CN

CD in CD

O

Q o VO in o O in o CN

G >1 o CN cn

O

m P r* CN cnp P

•rH o>

p

H

M on CD o CN o in CN P in in cn CN

a 0 03 CQ

p P CN CN CN CN CN

p r> 1 0 e £ p

CO o w

CO1 4-> g 5 d & G G n p P e P CD ft 4-3 > 0 B ><

<13 0 <3 <3 ft 03 3 s 3 03

O 0 03

a CD QC £ ft £ < £ < (/) o z a £
-36-

5. Comments

The DOE 2 program is now operational in Switzerland. Such a program is

a very useful tool in designing large buildings with complex mechanical

systems. It is also an important means of creating data to increase awareness of the possibilities for energy conservation. New and uncon- ventional designs can be tested for their benefit and feasability.

DOE 2 together with other programs, such as DEROB (see the next project

description), form a comprehensive package for computer aided design of

low energy and passive solar architecture. The running cost and labor re- quired in using such programs limit their use to complex, expensive buildings or as a research tool, however.

DOE 2 maintenance and development require the continuous effort of a staff expert in the particular computer system being used, in building physics, and in building mechanical system design practices in

Switzerland. Because of the skill and costs involved, it appears

logical to develop a central DOE 2 users' resource center for Switzerland where such work is conducted and maintenance and development

costs are shared over a broad base of program users.
- 37 -

2,4 DEROB IMPLEMENTATION AND VALIDATION

BACKGROUND

The computer program DEROB (Dynamic Energy Response of Buildings), written

by F. Arumi at the University of Texas at Austin has been installed and

checked against a test cabin in Maugwil (Direct Gain). The principal investigators for the project are S. Robert Hastings of EMPA and K.

Schenker of the ETHZ. Modifications were made to simplify use of the

program and a new user's manual was written in German. The first application of the program was a parametric study of attached greenhouses

under Zurich climate conditions. The results of the study and comments on the program have been published.
r

1. Objectives

- Install DEROB on the ETH computer to provide a rigorous, hourly simulation program for analyzing passive solar design approaches.

- Validate the program to assure that modifications required during installation did not alter the logic of the program.

- Write a user's guide in German, documenting the input, output, and

capabilities of the program plus changes made to the program to simplify its use.

- Conduct a parametric study to assess the capabilities of the program.

.

2. Approach

The program was installed on a CDC CYBER 175 computer. Installation

required a number of changes of both a compiler error nature and of a program execution nature.

After the program was installed a simple direct gain test cell (Maugwil)

with detailed measured temperature and energy use data was simulated

and the results compared to the measured data. After this initial

simulation work a number of desired input/output formats, and built-in

constants were changed to facilitate use of the program.

Finally, a parametric study was run on the heating and temperature performance of an attached greenhouse to assess the capabilities of the

program as a research tool.

3. Status

The program is now operational on the ETH main computer. Documentation

has been completed. The initial validation of the installation is

completed. A number of input/output simplifications have been completed. The greenhouse parametric study has been completed. Future work

will include updating or new installation of DEROB version 4, adapting

SI units if not available on the next version, and further parametric

studies with passive solar design approaches.
-39-

4. Example Results

Figure 13 illustrates the house used in the case study. Figures 14 and 15

graph temperature and heating loads as a function of one of the parameters

studied with DEROB: the number of glazed walls of a greenhouse. A common

design question is, "how does the number of glazed walls affect the greenhouse temperature and its ability to reduce house heating requirements?"

The graphs illustrate greenhouse performance given climate conditions of

Kloten for three mid-winter days. The data indicate that during low insolation, mid-winter periods the less non-south glazing, the better the

greenhouse performance.

Fig. 13 House geometry
Solar [

W/m

]

x

100

Heating

[

W]

x

100

- 40 -

[°CJ

40H Greenhouse Temp.

E + Wend glass no glass ends

Fig. 15 House heat load versus number of greenhouse glass end walls
-41-

5. Comments

DEROB is easier to use than a basic, unenhanced resistance-capacitance

network program. The input and output are tailored for building analysis

The program lacks sufficient diagnostics, however. Input is still sufficiently complex that errors are inevitable. Use of the program therefor

requires a fairly thorough understanding of some of the program logic in

order to diagnose errors.

The validation of the correct installation of the program must not be

interpreted as a full scale program validation effort. The exercise

demonstrated the sensitivity of input parameters or built-in constants,

which in practice are only educated guesses. Examples include the ground

reflectivity, the solar absorptivity of surfaces, and the in-place thermal insulation value of materials. By adjusting the initial values of

these estimated parameters, an acceptable fit could be achieved between

measured and simulated heating demand and temperature profiles of the

test cabin. The extent that these revisions reflect reality or compensate for possible inaccuracies of the program can only be determined by

an extended validation project. Validation of the program has been done

in the U.S. and a good agreement achieved.

Use of the program as a research tool to study the sensitivity of select

ed design parameters was very satisfactory. The level of detail possible

for the output is variable and excellent for studying individual surface

temperatures of components. The most serious drawback the program has is

the relatively high running costs and execution time required for runs of heating season length. It is expected that the newest version, not

yet installed, will execute in one third of the time presently required.
-42-

6. Publications

Hastings, S.R., "Analysis of an Attached Greenhouse in a Low Insolation

Northern Climate", Proceedings of the Sixth National Passive Solar Conference , American Section of the International Solar Energy Society,

Univ. of Delaware, Newark, DW. 19711, 1981.

Schenker, K., DEROB, Eine Anleitung fur Beniitzer , EMPA, Dubendorf,

July 1981.
- 43 -

* At

2,5 STESO TEST CABINS

BACKGROUND

The EPFL has built a series of test cabins to measure the performance

of different passive solar systems.

At this time seven instrumented test cabins are in service. Each has a replaceable front facade to permit exchanging various passive elements.

A comprehensive meteorological station as well as a central automatic

data acquisition system are located on the site.

Prof. A. Faist of the Solar Energy Group at the EPFL is the project

leader, Dr. J.-B. Gay, Mr. Y. Rey and Mr. C. Eriksson are principal

researchers. The project is financed by the EPFL, NF and NEFF.
1.

Objectives

- Measure different passive and hybrid solar energy collecting systems

under Swiss climatic conditions.

- Validate mathematical models of passive solar systems.

2. Approach

A series of passive solar designs have been tested for their performance

under Swiss climatic conditions using instrumented test cabins. The cabins

have been built side-by-side and share an on-site meteorological station

and data acquisition system to facilitate cross comparisons.

The meteorological parameters measured are: global solar radiation on horizontal, S., E., N. , and W. orientations; horizontal diffuse and

infrared radiation: wind speed and direction; and dry bulb temperature

and relative humidity.

The data acquisition system accomodates 120 channels which are measured

in intervals ranging from 30 seconds to 30 minutes. The data are stored

on magnetic tapes and later analyzed by the department of Physics at the

EPFL.

3. Status

Seven test cabins have been built and have undergone one or more winters

of measurement. The data are now being analyzed to generalize the results

to other climates of Switzerland.
-45-

4. Example Results

One configuration tested is a mass wall. The wall performed thermally

(on a heating season basis) comparable to a base case wall with an insulation value of 0.5 W/m2K. During unfavorable winter periods,

(solar gain less than 1.0 kWh/m2 day) a positive energy balance for the mass wall would require both double glazing and a selective absorbing

surface.

A free-standing greenhouse was also tested. The configuration was modified from its kit configuration to include opaque rigid insulation

on the north wall, north roof, and part of the sides. Water drums were added for thermal mass. A small nodal computer model was then written

to analyze the thermal performance of the greenhouse. A relatively good

agreement was eventually achieved between measured and computed performance, though the model is tailored specifically for that particular

greenhouse.

The dynamic thermal response of various window configurations was tested

in several direct gain test cabnis. The tested configurations included

selective transmittance glazing, moveable night insulation, bead wall,

and single, double and triple glazing. The experimenters concluded that

in the local climate, double glazing compared to single glazing would

save 160 kWh/m2 and that double glazing with a selective surface could

save an additional 90 kWh/m2 over the course of one heating season. Table 2 provides statistics on five of the test cabins.

Table 2 Swiss Test Cabins Statistics

Description of cabin Volume Aperture Capacity Loss

(m3

) (m2) (MJ/K) (W/K)

Low mass + IR glass 12.2 5 0.7 5.2

Low mass + Trombe Wall 12.2 5 1.0 5.2

High mass + H^O Wall 30.0 6.6 17.3 21.5

High mass direct gain 10.4 2.3 4.4 12.5

Greenhouse + H^O stor. 6.7 9.5 4.2 8.6
-46

5 . Comments

The test cells at Lausanne have been an important step in the development of passive solar research. Their usefulness is twofold: to demonstrate the performance of various passive solar elements under local

conditions, and to provide immediate data from relatively simple cases

to validate mathematical models. The LESO structure, reported later

in this document, is a next generation set of test cells.

6. Publications

1. J.-B. Gay, A. Faist, "Dynamic Heat Balance of Windows",

Pergamon Press Ltd. , London; International Conference on Building Energy Management, Porto, Portugal, May 1980

2. N. Morel, A. Faist, "Thermocirculation in solar installations - Computer simulation and comparison with measurements"

Pergamon Press Ltd - London (International Conference on Building

Energy Management, Porto, Portugal, May 1980

3. S. Al-Jrab, G.-R. Perrin, "Mesures de rayonnement infra-rouge et

estimation des pertes par rayonnement vers la voute celeste"

Compte-rendu du 2eme Symposium Solaire EPFL, Section A,

Lausanne, October 1980
- 47 -

2.6 SOLAR TRAP

BACKGROUND

A hybrid* passive solar concept has been tested in a specially con- structed test module and a house using the tested concept has been built.

The concept addresses the problem that direct solar gain may be impeded

by occupants shading windows to reduce glare or overheating. The "solar

trap" concept employs a solar absorber blind lowered between the outer

and inner glazing of a window. Sun-heated air is then extracted from the

glazing space and circulated either to the room or to thermal storage.

When direct gain is not objectionable to the occupant, the blind can be

raised and full sunlight admitted into the space. The project was lead

by Dr. C. Filleux of Basler & Hofmann, Engineers in Zurich.

Instrumentation and data collection were conducted by EPFL.

*A passive system augmented by a small circulating fan or pump.
-48-

1. Objectives

- Measure the performance of a hybrid window solar collector, with rockbed thermal storage relative to the performance of a simple direct gain

massive configuration.

2. Approach

Two 15 m

3 side-by-side test cells have been constructed and instrumented to evaluate the effectiveness of a hybrid, window collector, rock

bed storage approach and a direct gain, thermal mass approach.

The mass cell, which serves as a reference, includes 3040 kg of

brick on the floor and interior walls. This increases the thermal capacity from the 500 Wh/K of the basic test cell (the same for both cabins)

to 1400 Wh/K. The south facing triple glazed window area is 2.9 m

2

. 13

temperature sensors are incorporated in the cell to measure air and

critical surface temperatures.

The solar trap cell includes 3.8 m

2 of double glazing at the outer

window opening (housing the absorber blind) and a similar 2.9 m

2 of

aperture to the cabin interior. The rock storage contains 1.7 m

3 of

rock or approximately 2720 kg, which is thermally isolated by 60 mm of

insulation from the cabin interior. The fan connecting the window to

the storage has a 110 W motor. The cabin performance is measured with

45 sensors located on the surface of each wall, at different heights

within the cabin, within the solar trap air space, at its inlets and

outlets, and at different levels in the rock bed storage.

Meteorological data are provided by an on-site weather station.

The solar trap system operates as follows:

When the temperature in the solar trap window reaches 30 - 45°C, (varies

by the time of year), a ventilator is activated automatically. Air is

then circulated to the rock bed storage, as shown in the figure 16a.

The heat is retrieved from storage when needed by circulating room air
-49-

through the rock bed. Alternatively, the room can be heated by circulating air from the rock bed through a heat exchange wall (hypocaustum) in

a closed loop. At night, the blind is lowered. The blind in combination

with the triple glazing performs as a very well insulated window.

To reduce summer overheating of the space a thermosiphon cooling mode

is possible, as shown in figure 16b. Cool air from the north side of

the cell is drawn through the storage, across the sun heated blinds between

the two glazings and then convected to the outdoors. An airflow rate of

50 m

3 /h has been measured. Peak temperatures in the cell are thus lowered

as much as 10°C.

Virtually no solar radiation enters the room with the blinds shut. The

surface temperature of the blinds reaches up to 70°C resulting in an inner glazing temperature of more than 40°C, however. Consequently the

test cell is still subject to indirect heating and subsequent overheating. A heat reflective film on the inner glazing has been tested as a solution to this problem. During solar collection periods the film

reduced test cell temperatures 2 - 3°C. During nights the reflective

film would also provide additional insulation. A more plausible solution to overheating is probably exterior shading, such as by an overhang or awning.

3. Status

Data collection is now completed for each of the three modes of operation: hybrid heating, passive heating, and passive cooling. The data

have been analyzed and design recommendations published in a final

report. A prototype house has been constructed and is currently being

instrumented.
- 50 -

WMM5WMMM

Heat storage in rock bed

Window roll blind

solar collector

Heat gain

Heat loss

Fig. 16a Active collection mode

Fig. 16 b Summer Thermosyphoning Mode
-51-

4. Example Results

Solar Trap and direct gain (test cell) temperatures are compared for

two characteristic periods in the figures 17 and 18. Building load

coefficients exclusive of the window area are identical for both cells.

The resulting solar contribution in the Solar Trap cell reached 85 %

in October/November and 35 % in December respectively. Conditions of

comfort as indicated by the inside temperature, were significantly

better in the Solar Trap cell than in the mass cell.

5 . Comments

The results obtained to date with the ’’Solar Trap" window-collector and

the rockbed storage show that a well designed system may supply more

than 50 percent of the heat needed during winter months. For short-time

thermal storage the rockbed performs adequately.

While the performance of the solar trap appears impressive relative to

direct gain solar heating, it must be noted that the direct gain test

cell did not include any night insulation and hence experienced substantial night radiation losses and subsequently large temperature ex- cursions. While a practical night insulation is lacking in the Swiss

market, the potential of a direct gain system should not be underestimated based on the data this project provides.

Future research would be useful considering the coupling of the solar

trap window with a latent heat storage system which would decrease

volume required by the present rock storage system. The fan motor size

could also thereby be decreased.

6. Publications

"Forschungsprojekt Solar Trap: Passive und aktive Sonnenenergienutzung

bei Gebauden", Thomas V. Kurer, Reto Lang, Basler & Hofmann,

Forchstrasse. 395, 8029 ZUrich, Switzerland, April 1981
S.GIobal

Solar

Radiation

[

W

/

m

2]

- 52 -

Day of the Year

1000

800

600

400

200

0

Fig. 17 Test Cell Performance in October/ November

-

i - 1

,

i

-

1

- r 1

ft

1

/ JL_v\.

299 300 301 302 303 304 305 306

Day of the Year
Global

Radiation

[W/m 2

]

Cell

Temperature

[°C]

- 53 -

Day of the Year

1000

800

600

400

200

359 360 361 362 363

Day of the Year

Fig.18 Test Cell Performance in Depember

-55-

2,7 NAUGWIL TEST CABINS

BACKGROUND

Two test cabins have been constructed to measure the importance of the

radiative properties of a building facade relative to the building’s

heating demand. The project was begun in 1979 and is scheduled for com- pletion in 1982. Prof. K. Kneubiihl of the Solid State Physics Laboratory

at the ETH-Z and R. Sagelsdorff and T. Frank of EMPA are the project

leaders
Reflectivity

()

-56-

1. Objectives

- Measure how the radiation properties of building facade materials, in

interaction with solar radiation and sky counterradiation properties,

affect the heat balance of the building envelope.

- Measure the energy consequences of a south-facing window regarding

the above radiation properties.

- Provide measured data to validate a computer model on the role of

radiation mechanisms in determining heating and cooling loads.

2. Approach

Two test cabins were constructed, each 3.0 x 3.0 x 4.5 m (wx hx 1).

Construction details and specifications are shown on the following page.

One cabin has a conventional clear annodized aluminum exterior

(E = 0.92), the other a selective reflective chromated aluminum

o exterior (E

q = 0.07). Figure 19 illustrates these properties.

Fig. 19 Radiation Properties of the two Types of Aluminium Panels
3

000

mm

-57-

Fig. 20 a Cabin No. 1

( Anodized Al. Skin )

Temperature sensors

Fig. 20 b Cabin No. 2

( Conversion coated skin )

Cabin No. 1.

-Double glazed windows

1800 X 1900 nun with

exterior roll blind.

-Clear anodized

aluminum exterior.

-70mm polystyrene

in walls and roof.

-60mm polystyrene

in floor.

-60mm gypsum panels

interior of black wall

(north wall interior)

-1000 kg brick floor

-Four 250W IR lamps as heat source.

-10 air temperature

probes (each corner

and center) placed

low and high.

Cabin No. 2

(Differences from No.l)

-No window,

two sheets of acrylic

over south facade.

-Low emissivity aluminum facades and roof.

-60mm gypsum panel

south wall interior.

-Roll blind between

acrylic sheets and

opaque wall.

-Temperatures measured

at surface of glazing,

air space, surface of

roll blind, surface of

aluminum.
-58-

During the first winter of the project measurements were taken of all

inside and outside cabin surface temperatures, inside air temperatures

at ten locations per cabin, and electric heating consumption of each

cabin. A weather station at the site recorded ambient air temperature

and humidity; wind speed and direction; global solar radiation on horizontal, N. , S., E., and W. vertical surfaces; diffuse radiation on

a horizontal surface, and infrared radiation on a horizontal and a south vertical surface. Data from the two test cabins and the weather

station were recorded with a 140 channel data acquisition system

controlled by a programmable desk computer located in the adjacent

Maugwil house.

During the second winter, a double glazed window 1800 x 1900 mm was incorporated in the south facade of the annodized aluminum cabin. An automated conventional aluminum exterior roll blind was installed outside

the window. The blind, under the control of the desk computer, was lowered when the solar intensity fell below 5 w/m2

.

The conversion coated aluminum cabin was outfitted with an acrylic

double glazing covering the entire south facade. An automated blind

was installed in the air space between the aluminum facade and the

acrylic sheets. The blind was operated by the same control program as used by the other cabin. Both cabins contained internal mass to even

out the temperature extremes. Both cabins were heated by four 250 watt

infrared lamps oriented 45° off axis in plan to provide more uniform

interior surface irradiation. The lamps were thermostatically controlled

to heat the cabins to 20°C.

3. Status

The second winter of data collection has now been completed. A computer

program has been written which assembles raw data from the cabins and

generates daily summaries. Sufficient data are now available to permit

the validation of the mathematical simulation model and it is currently
-59-

under revision and further development. Upon completion of the data

collection a final report assessing the effectiveness of the various

strategies will be completed in late 1982. The cabins have recently

been disassembled, transported to EMPA, and reassembled for a third

winter of measurement.

4. Example Results

The exterior surface temperature profiles for the anodized aluminum

facade and the conversion coated aluminum facade relative to the am- bient temperature are shown in figure 21. The conversion coated facade

temperature is always higher than both the ambient and the anodized

facade temperatures. During a sunny day this difference is most pronounced.

During clear nights the anodized face temperature falls below the ambient

temperature due the substantial night sky radiation losses.

Fig. 21 West Wall Exterior Surface Temp. *
-60-

Figure 22 illustrates the surface temperatures of the south facades

of the two cabins relative to the ambient temperature but here the south

facade of the conversion coated facade has an acrylic cover glazing. The

glazing and trapped air space substantially amplify the difference in

surface temperatures between the cabins. The conversion coated surface

behind the glazing reached 70°C compared to the unprotected anodized sur- face reaching 18°C on a day where the ambient temperature peaked at 2°C.

Fig. 22 South Wall Exterior Surface Temp.
- 61 -

Figure 23 illustrates the end result of the surface temperature differen

ces between the two cabins, namely, the difference in power consumption

required to maintain 20°C. During the nights the conversion coated cabin

required less power due to the reduction of IR radiation losses. During

the day the anodized cabin with the window required less power for

heating due to the solar gain of the window.

Fig. 23 Heating Power Consumption
- 62 -

5 . Comments

The primary objective of this experiment is to study the consequences

of a selective reflective surfaced building shell in comparison to a conventional aluminum panel type building shell. To provide an extreme

contrast, the roof as well as the four sides of the cabins are clad with

the same aluminium or coated aluminum. By treating the roof similarly,

the maximum sky exposure of this surface provides pronounced differentiation between the two types of surfaces. In interpreting the results,

however, care must be exercised in making projections for real

buildings because of the unlikelihood of their having aluminum clad

roofs. The cabin outfitted with an acrylic sheet over the south-facing

selective reflective aluminium provides a valuable measure of the effect

wind has on stripping away heat from the surface of the cabin, in

contrast to heat lost by reradiation from the aluminum to the ambient

environment.

The measurements indicate that when a building envelope is specially

treated to reduce IR radiation heat losses a considerable reduction in

auxiliary heating is possible. Energy savings from reduced heating re- quirements can be offset by increased cooling requirements in the summer,

however.

In future years it would be useful to investigate reconfigurations of

the test cabins. For example, the conversion coated cabin could be

configured with a window to provide direct solar gain, more realistically

representing an actual application. The other test cabin could be outfitted with an attached sunspace with insulated opaque ends, double glazing,

night insulation, and a water wall separating the test cabin from the sun

space. Such a configuration would provide valuable measured data on the

number of hours the sunspace temperature and humidity were within the com fort band, and the annual heating contribution the sunspace was able to

make to the test cabin. Also, auxiliary heating requirements to maintain

the sunspace above the minimum tolerance temperature of specified plants

could be measured.
-63-

Another valuable experiment would be to outfit the cabin having the selective reflective coating with a slatted metal sunscreen. The blades of the

sunscreen would be fixed at an angle to block summer sun but admit winter

sun. Such a configuration would reduce the summer overheat problem which

the selctive reflective surface exacerbates. The screen would further act

as a partial wind screen in winter, helping preserve the boundary layer

of air at the facade.

For both the sunspace configuration and the sunscreen selective reflective

configuration, it is worth considering painting the roofs gray, approximating the color of aged built-up roofs, or installing a curb and placing

gravel on the roof. Either of these two conditions would more realistically

represent actual roof conditions.

6. Publications

Kalin, R. und Kneubiihl, F. , "Die Verminderung des Warmeverbrauchs von

Gebauden durch Infrarotverspiegelung von Fenstern, Fassaden und Dachern",

Gesundheitsingenieur Nr. 98, 1977

Kneubiihl, F. , Frank, T., et.al. "Energy savings by Reduction of the

Thermal Radiation from Building Envelopes", International Conference

on Building Energy Management, Porto, Portugal, May 1980.

Sagelsdorff, R. , Zuricher, Ch. , Frank, T. "Einfluss der Strahlungsvorgange an der Gebaudehiille auf den Energieverbrauch" Proceedings of

the 11. Kongress der Internationalen Vereinigung fiir Briicken- und

Hochbau, Wien, Aug. 1980.
- 64-

r
- 65 -

2.8 THREE PASSIVE SOLAR HOUSES

BACKGROUND

Three passive and two active solar houses in Switzerland are being monitored and computer modeled. This work is a part of International Energy

Agency Task I. G.-R. Perrin of the Solar Energy Group of the EPFL *, is

the project leader. The data are intended as a basis for commenting on

the effectiveness of various passive solar strategies under Swiss con- ditions of climate and architectural style.

* Laboratoire de Pysique Theorique, Groupe de Recherche en Energie

Solaire (Professeur A. Faist)

Institut de Thermique Appliquee (Professeur P. Suter)
- 66 -

1. Objectives

- Assess the performance of solar houses (active & passive) in their

local climate.

- Provide a means to validate a thermal network simulation program,

"PASSIM” written at the EPFL for passive solar systems, and the TRNSYS

program written at Madison, WI, (USA) for active solar systems.

2. Approach / Method

Five solar houses were selected for monitoring. These were:

1.

) a house in Begnins

2.

) a house in Les Geneveys/Coffrane

3

) a house in Renens

4.

) a house in Payerne

5

) a house in Savuit

Each house will now be discussed.

1) The "Begnins" house, illustrated in Figure 24, is a direct gain house

with a recently added attached greenhouse. The house was constructed in

1977. It has been monitored from autumn 1978 through summer 1980. The walls

have an insulation value of 0.42 W/m2 K and the roof has value of 0.2 W/m2K. A 64

channel analog 8 pulse counter with integrator, scanner, and magnetic

cartridge recorder has been used to collect measured data.
15.80

v

„

2.20

v

4.00m

- 67 -

?

Middle Level

Fig. 24 Begnins House Plan and Section
- 68 -

2) The "Geneveys" house is a passive and active solar house, built in

1979. Measurement started in the spring of 1979 and will continue

through the summer of 1981. The building is well insulated (walls

0.32 W/m2 K, roof 0.20 W/m2 K) . The floor plan incorporates a buffer

zone on the north side. A greenhouse is the primary passive solar

element. It is double glazed and has a reflective aluminized Polyester

curtain used during winter nights as infrared reflective insulation

and during summer days as a sun shade. The active system consists of

24 m

2 of air collectors with 4 m3 of rock thermal storage plus a rockbed under the ground floor with a pipe system for channeling the

air evenly through the rockbed. This system has not yet been completed.

3) The "Renens" house completed in 1980, has a Trombe wall (14 m

2

) and an integrated greenhouse. The monitoring period will end early in

1982. A Hewlett Packard data acquisition system is used (HP 9835 A + scanner + digital voltmeter + pulse counter + HP cassette recorder).

The house is well insulated (walls 0.3 W/m2 K, roof 0.2 W/m2 K) and is

tight (0.3 - 0.5 air changes per hour).

4) The "Payerne" house is a conventional Swiss single dwelling with an integrated active liquid solar system 20 m

2

, 43° Tilt, (south-west

orientation). The system has been measured since January 1980. The

house is well insulated (walls 0.4 W/m2K) . A 64 channel analog datalogger, and 12 pulse counter with integrator are used with a magnetic

cartridge recorder.

5) The "Savuit" house is a single dwelling with an active solar system

(22 m

2

) isolated from the main building. This system is rather complicated but allows the researcher to examine the effect of variations

of storage mass to collector area. The system is instrumented with a 64 channel analog, 8 pulse counter data-logger.
-69-

Measured parameters at each of the five buildings include local meteorological conditions, solar system performance, building inside air

temperatures, infiltration rates, and back-up heating energy con- sumption. The method of analysis and documentation is the same for the

three passive houses (IEA Reporting Format). The "Begnins" house project

will now be described in more detail.

The "Begnins” house is a direct gain design. The southern facade is en- tirely windows (28 m

2 of glass). Local overheating is minimized by the

tiled concrete floor, masonry walls and masonry mass incorporating a fireplace (total 43 m

3 of concrete). The largely open, two-story floor

plan provides free air circulation, minimizing temperature stratification

(confirmed by measurement). During the night, roll blinds are lowered on

the south windows and moveable insulating panels are placed in the east

and west-facing windows.

A wood stove is the principle auxiliary heat source.

3. Status

Data collection from the "Begnins" house is completed.

Data collection from the "Geneveys/Coffrane" house is completed. New

data will probably be collected when the air system becomes operational.

Data collection in Renens , Payerne, and Savuit is still underway and will

be completed at the end of 1981.

Available data from the three passive buildings are currently being used

to validate a thermal network program, PASSIM, and one of the two active

systems is being used to validate the TENSYS program.
-70-

4. Example results

After two and a half years of experience, and one year of measurements

from the Begnins house, the project researchers were disappointed that

the solar fraction was smaller than expected (30 - 47 percent). In fact,

initially they had overestimated the losses of the building and under

estimated the internal heat generated by the lighting, electric equipment and people. These influences in combination substantially reduce the

heating period, thereby reducing the period when solar collection can be

credited. The heat load of the building is small because the owners prefer

room temperatures of 16 - 19° rather than the more common 20 - 22°C, and

because in a relatively well-insulated and airtight building the internally generated heat meets a substantial proportion (30 - 60 percent) of

the load.

These considerations do not mean that the building is a poor solar design. They prove, on the contrary, that it is possible even given Swiss

climate conditions to build a low energy consuming house taking advantage of solar direct gain. Figure 25 illustrates the performance of the

Begnins house. The minimal extent of the temperature stratification which

occurs even on clear days is shown. Table 3 details the low extent of

energy use by the Begnins house.
-71-

W/m 2 600

500

400

300

200

100

0

08 h 00 21 h 21 h 21 h

~4I —*

Day 352 Day 353 Day 354

Fig. 25 Temperature Stratification of the Begnins House

1

-South V<jrtical Gl<Dbal Solar Radiation

1 A u-/} i L i
-72-

Table 3 Begnins House Energy Consumption 1979-80

Mean

temp.

Interior

temg.

Miscellaneous int.

gains (kWh)

Electric

Aux. heat

(kWh)

Wood

Estimated)

(kWh)

JAN -0.8 - 872 - 3600

FEB 4.1 - 452 - 3600

MAR 3.2 14.10 443 800 "" r APR 6.3 16.27 451 330 - MAY 14.8 20.20 525 - - JUN 14.6 20. 40 498 - - JUL 20.2 23.20 499 - - AUG 17.1 21.50 508 - - SEP 16.4 22.20 423 - - OCT 11.7 19.00 478 - - NOV 3.6 18.70 417 56.80 3600

DEC 5.6 17.60 414 273.00 3600

JAN 0.2 17.60 452 405 3600

FEB 3.5 19.80 431 33 3600

MAR 4.4 18.80 433 333 2700

APR 6. 3 20.20 389 22 2700

MAY 9.4 19.70 363 - 2000

JUN 14.0 20.20 319 - 750

JUL 13.9 19. 30 359 — 85
-73-

5 . Comments

Monitoring of the three passive solar buildings and subsequent interpretation of the data have been difficult, as is often the case with

occupied structures. In the house at "Begnins" , for example, it is difficult to measure the amount of heat generated when the fireplace is used.

Further, the use of the wood stove in the kitchen generates so much heat

that concurrent solar gain is not useful. The task of calculating a solar

saving fraction from the measured data is therefore not a clear cut procedure given the use patterns of the house.

The performance of the Trombe wall of the "Renens" house revealed the

importance of thermally isolating the Trombe wall from the basement wall

(not done in this example). The house, none the less, provided valuable

measured data to check various mathematical models.

After eighteen months of measurement the performance of the "Geneveys/

Coffrane" house appears impressive. The good insulation and tightness

of the house drastically reduce the heating load. The greenhouse and

direct gain meet more than 60 percent of the heating load, 24 percent

is provided by the internal gain. Due to the high efficiency of the

passive system and the small load, the active system participates in

meeting only 4 percent of needed space heating. This small fraction

drastically increases the pay-back time. The data being collected from

the greenhouse will be a valuable contribution to the knowledge on greenhouses as passive solar elements in the Swiss climate. The two

active systems have provided valuable information in areas such as:

- collector efficiency under in-service conditions

- charging and discharging efficiencies of the storage

- floor heating dynamics.
-74-

6. Publications

Morel, N. , Perrin, G.-R., Razafindraibe , A. "Passive Solar House

Begnins", Ecole Polytechnique Federale de Lausanne, Dept. Physique

Lausanne, Switzerland, June 1981

Morel, N., Perrin, G.-R., Razafindraibe, A. "Passive Solar House

' Les Geneveys*", Ecole Polytechnique Federale de Lausanne, Dept.

Physique Lausanne, Switzerland, June 1981

Razafindraibe, A., Faist, A. "Acquisition and treatment of data

collected from solar houses", Building Energy Management, Porto,

Portugal, May 1980

Suter, P., "Instrumentation for the Monitoring of solar installations"

Institut Thermique Appliquee EPFL, Building Energy Management, Porto,

0. Fernandes, A. Faist, J. Woods) May 1980

Hadorn, Chuard, D. , "Simulation d'une maison solaire avec le programme

TRNSYS", 2eme Symposium sur la R & D en Energie solaire en Suisse,

EPF Lausanne, October 1980

Calatayud, C., Nilsson, M. , "Travaux AIE, Installations actives.

Validation", 2eme Symposium sur la R & D en Energie Solaire en Suisse,

EPF Lausanne, Oktober 1980

Perrin, G.-R., "Reporting Format" GRES - EPFL, February 1980

Perrin, G.-R., "Procedes de mesures sur systemes solaires passivs"

GRES - EPFL, May 1980
-75-

2.9 AN ATTACHED GREENHOUSE NEAR ZUG

BACKGROUND

A two story attached greenhouse was built as a passive element of a new

house near Zug. The designer of the house, a student at the ETH-Z has

subsequently instrumented the greenhouse to monitor the actual heat con tribution of the greenhouse and the comfort conditions it achieves. The

monitoring was begun in March of 1981. The principal contact for the

project is Mr. I. Moschlin, at Klingenstrasse 35, CH 8005 Zurich,

Switzerland.
-76-

1. Objective

- Collect data on surface temperatures and air temperatures of a greenhouse in order to evaluate its energy and comfort performance.

- Collect data on the surface temperature of the wall above the greenhouse to evaluate the benefit of the greenhouse relative to the wall

alone without a greenhouse.

2. Approach

In order to monitor the greenhouse twelve sensors were installed as follows

:

Sensor

Number

12

3,

4

5, 6

7

8

9, 10

11

12

3. Status

Location

Tiled stove(l) outer surface temp.

Living rm. air temp.

Mass wall interior surface temp.

Mass wall sunspace surface temp.

Mass wall exterior surface temp.

Sunspace floor temp

Sunspace air temp.

Ambient temp.

Hours of sunshine.

Data collection for a two month sample period has been completed and the

strip charts from the twelve point recorder are now being evaluated.

(1) a Tiled stove is a ceramic tile wood fired oven used for space heating
-77-

4. Example Results

The following two curves are plots from measured data from the 16th of

February, 1981.

Figure 26 illustrates the effect the greenhouse has on the surface

temperature of the south wall. The upper curve which is the wall

in the greenhouse is ten to twelve degrees C warmer than the temperature of the same wall at a location above and outside the greenhouse

shown in the lower curve.

Figure 27 shows the greenhouse air temperature in comparison with outside

air temperature and relative solar radiation. The latter term refers to

temperatures recorded by a temperature probe mounted on a black metal disc

mounted vertically in the greenhouse. No attempt was made to calibrate the

temperature to solar radiation in absolute terms. Noteworthy are the lag

between the beginning of solar gain and greenhouse temperature rise, and

the almost immediate drop in the greenhouse temperature occurring as solar

gain drops off for the day. The lag in the morning can be explained by the

fact that the greenhouse faces south and west, and therefore received only

oblique morning sun. The immediate drop in temperature in the evening is due

to the minimal contribution of the thermal mass of the wall, and the lack of

any night insulation.

Fig. 26 Moschlin House Wall Surface Temperatures
-78-

5 . Comments

While data were collected for only a two month period, this project provides a useful reference point which when added to data from other projects will permit insights on attached greenhouse energy performance.

The white wall surfaces as they exist today probably reflect as much as 2/3 of the solar radiation back out through the glass. A dark color

would be better for absorbing solar gain. The designer’s reason for the

light color was to minimize the number of days when the greenhouse would

be overheated to the point of being uninhabitable. A light colored fabric

could be unrolled down the facade during the summer to achieve the same
- 79 -

objective. A month of data collecting in the summer would also be useful

to assess comfort problems. The loss of use of the space occupied by

the greenhouse during the summer would certainly be a heavy cost.

Night insulation would also be an interesting variable to examine. The

greenhouse is presently ribbed plexiglass double glazing and has a large sky exposure. How night insulation could be fitted to the complex

geometry of the roof is clearly a problem, however.

A final worthwhile exercise would be to calculate how optimal the existing glass orientation is for the local climate. The designer's personal experience with the region indicated that mornings are typically

overcast. The majority of hours of sunlight occur in the afternoon. A

computer analysis of climate data for the region on a month-by-month

basis could substantiate this belief as well as provide useful design

data for calculating the benefit of west-facing glazing versus merely

providing a well-insulated opaque wall to the west.
- 80 -

.
-81-

2.10 LIMMATSTRASSE APARTMENT BUILDING RETROFIT

BACKGROUND

An apartment complex in ZUrich was retrofitted by the city to improve

comfort conditions. The project provided an opportunity to measure the

extent that standard retrofit practices actually do improve comfort.

In addition, a number of alternative heating systems were installed to

experiment with their effectiveness under "in-use" conditions. Included

were various active solar systems, heat exchanger systems, a gas powered

heat pump system, and a complex highly individual heating control system.

The project was begun in 1976 and is scheduled to be completed in 1982.

Dr. Jurg Gass of the Swiss Federal Laboratories for Material Testing is

the contact for technical information.
-82-

1. Objectives

- Measure the energy- consumption and possible energy-saving resulting

from solar and heat pump systems and conservation measures.

- Investigate the influence of different temperature regulation systems on

average room temperature.

- Compare the performance of ’'under-roof" and "on-roof" solar heat

absorbers

.

- Collect statistical data on domestic hot water consumption.

- Investigate possible energy savings from thermostat night setback

of the heating.

2. Approach / Method

Four of twenty five, seventy-year old apartment blocks are being measured. The four units all have a similar orientation and identical layout.

The shell of block "0" has been unmodified to provide a reference case. Only the interior and the plumbing installations have been renovated.

The building envelope heat losses of block "1" have been substantially

reduced by replacement windows with triple glazing and added insulation

(value ca. 0.5 W/m2K) on north walls. Thermostatic valves have been

installed on radiators in south-facing rooms. On the roof are 24 m

2 of

double-glazed flat-plate collectors with a 1.8 m

3 storage for domestic

hot water.

Block "2" has been retrofitted with superior insulation (value ca. 0.4 W/m2 K) on all walls.

A microprocessor-controlled heat regulation system allows individually

controlled temperature programs (4 daily changes) for each room. Finally,

a gas engine powered heat-pump provides heat for space and water heating

by extracting heat from:
-83-

1) a system of roof solar absorbers (2 km of plastic tubing) divided

into 2 systems, one lying flat on top of the roof, the other lying

under the roof tiles. Both are connected to low- temperature

storage tank

2) a gray water* holding tank.

3) the air in the heat pump gas engine room.

4) the coolant of the gas engine which drives the heat pump.

5) the exhaust from the gas engine.

Reference Building

Typ 0

Normal Buildina Typ I

Normal Building Experimental Building

with solar collector with heat collection

for warm water Typ 2

Data collection is controlled by a microprocessor and programmed through

a video-terminal . Data are recorded on a magnetic casette-tape recorder

with a capacity of 1.8 MBytes per casette.

This unit is located in one of the type 2 apartments, which serves as a central data collection station connected to all the other apartments.

The parameters measured are:

* Gray water is waste water from sources other than toilets or urinals.
-84-

1) Weather:

- Air-temperature

- Global radiation-horizontal

- Diffuse radiation-horizontal

- Global radiation on collectors

- Wind speed

2) Block 0 (Reference) and Block 1 (Conservation)

- air temperature in the basement, attic, two stairwells, and twelve

apartment rooms

- return water temperature of three radiators

- heat supplied for space heating

3) Block 1 Solar

Heat gain from the solar collector, heat consumption for domestic hot

water for each apartment, and the city water inlet temperature.

4) Block 2 (Heat collection)

- air temperature in the attic, hall and three apartments

- return temperature for every radiator

- heat gain from the two roof tube collectors

- temperatures of the domestic hot water preheat boiler, gray water

holding tank water, heat pump engine coolant, heat pump engine

exhaust, and heat pump engine room air

- space and water heat

The heat-collection system has 20 temperature-sensors, 9 water flow

meters, 1 ultrasonic flow meter in the grey water circulation, and

1 gas-counter. All temperature measurements are momentary hourly

values

A monthly standard evaluation of the data is made, to provide a continous check of the data throughout the two years of measurement.

Important parameters are evaluated at 10 day intervals.
-85-

3. Status

Collection of data was started in March 1980. A computer program has been

written and is now in use to assemble the raw data from the cassettes and

produce period summaries of climate data, building interior temperatures

and heat use.

Evaluation of the various systems from the operating data is in progress.

Final analysis will begin upon the completion of the measurement phase

in 1982.

4. Example Results

Figure 29 illustrates the reduction of required heating resulting from

adding insulation to the north wall and replacing the window/storm

windows with new triple-glazed window. It is interesting to note

that the measured heating requirement in the spring was greater

for a retrofitted apartment than for an unretrofitted apartment. Possible

explanations for this include occupant factors, the slightly different

orientation of the two buildings, and the effect of triple glass reducing

solar gain during a period when solar and internal gains begin to match

heat load.

Figure 30 compares two solar absorber systems for heating water.

One system is simply flexible black plastic tubing laid out on a flat

roof. The second is tubing run in the space directly beneath the roof

tiles. Again, the curves are measured results. The data indicate that

the under-roof absorber performs better in winter, while the above-roof

absorber performs better in summer. This may be explained first by the

fact that the above-roof absorber lies flat while the under-roof absorber is on a south sloping exposure. The variation of summer and winter

sun angles therefor help explain the difference in performance.
-36-

Fig. 29 Comparison of Heating Energy Use by Base Case and Retrofit Building

Fig. 30 Roof Solar Absorbers- Heat collected per 10 Day Intervals
-87-

Figure 31 illustrates the monthly energy uses and energy sources

for the apartment block with the combined solar and heat pump system.

A direct correlation between ambient heat sources and the heat

provided by the roof solar absorbers is not possible because ambient

sources include heat recovery from gray water. This factor is extreme

ly user sensitive. The monthly data presented in this figure are presented on an annual basis in Figure 32. Note that when the

consumed energy is divided by the purchased energy the result is 0.99

including all the system and distribution losses, and computed on an annual basis.
- 88 -

Exhaust Losses

Domestic Hot Water

Space Heating

Fig. 32 Energy Flow Diagram for the Solar Retrofit Apartment Block

5 . Comments

Data obtained from monitoring the Limmatstrasse project will permit an in-depth evaluation of the different retrofit strategies employed. Given

the very large number of buildings retrofitted to conserve energy, it seems necessary to measure a sample of buildings to verify that the

expected savings are being achieved. Limmatstrasse goes beyond

providing a check on the savings possible from conventional retrofit

and includes experimentation with new and highly complex alternative heating and water heating systems.

It would be useful to expand the project beyond the number of options

actually implemented by computer-simulating a range of alternatives not

implemented. Of particular interest would be a simulation series of

passive solar retrofit alternatives. One such alternative might be re- placing the south-facing roof slopes with glazing, thereby converting

the attic into a greenhouse area . (Fig. 33) . Heat so collected could be

used for clothes drying (clothes are presently dried on roof clothes

lines, weather permitting) or for heating the apartments below.
-89

Other variations might include add-on solar air collectors appended to

the building facade, addition of an experimental window night insulation

system, or retrofit Trombe wall applications. On a grand scale, it

would be useful to calculate the effect of building a space frame over

the entire court space of one of the apartment complexes. The space

frame could then be profiled in a series of triangular vaults with

glazing to the south and opaque insulated roof to the north. The entire

court space, rather than being merely more surface area for building

envelope heat loss, could become a solar atrium, (fig. 34.)
- 90 -
-91-

6. Publications

Brunner, C. , Gass, J. , Stachura, P. "Wohnkolonie Limmatstrasse - Energie Sanierung" (Zwischenbericht: Messperiode 1980/81), EMPA,

June 1981

Hartmann, P., EMPA-report Nr. 3643, "Umbau Wohnkolonie Limmatstrasse"

Schweizer Ingenieur und Architekt Nr. 20/80, p. 470-476, Mai 1980,

Gass, J., "Messtechnische Ueberprttfung der Sanierung der Wohnkolonie

Limmatstrasse", Erstes Schweizerisches Status Seminar: Warmeschutzforschung im Kochbau, EMPA, 8600 Diibendorf, Oct. 1980.
- 92 -

'
-93-

2,11 CHAUMIERE APARTMENT BUILDING

BACKGROUND

A four story, 24 unit apartment building in Lausanne has been instrumented to provide data for calibrating energy calculation models. Dr. P.

Favre of the Federal Institute of Technology in Lausanne initiated this

project in 1979. Data collection will be continued for two years, ending

in 1982. Because of the extended period of measurement, special attention was given to make the sensors as inconspicous as possible. One

apartment unit is unoccupied to provide a base case for estimating occu- pant influence on heating demand.
-94-

1. Objectives

- Provide detailed data on the thermal balance of the building.

- Calculate the energy consumption of an occupied and a vacant apartment

in order to evaluate the occupants' influence on the energy use.

2. Approach / Method

A representative four story apartment building belonging to the city of

Lausanne was selected for measurement. The selection of the building to

be instrumented was difficult. A list of possible buildings was developed on the basis of location, size, representativeness of design, and rent

levels. The majority of the possible buildings subsequently had to be

eliminated because of landlord or occupant opposition to "such an intrusion of privacy". Only the town of Lausanne as owner finally agreed to

have one of it's apartment buildings instrumented. 17 out of 24 residents agreed to participate in the experiment.

The building, which dates from 1957 is a four story structure with six

apartments on each floor. Brick walls 25 cm thick support reinforced con- crete floors. The windows are double glazed.

Two kind of measurements are being made:

1) Dynamic measurements consisting of:

- interior and exterior wall surface temperatures

- heat flux through the walls

- temperature and water flow from and to the heating system

- room air temperatures

- interior climate (room air temperature)

- exterior climate (radiation, temperature, wind, humidity)
95

2) Static measurements:

- determination of wall construction for theoretical evaluation of

thermal characteristics

- window air tightness measurement

- infra-red photography of the building in order to provide a refe- rence for evaluating data from the wall surface temperature sensors.

A vacant apartment has been instrumented more thoroughly. It will be norm

ally occupied the second year of measuring. This will provide an example

of the effects of occupancy on heating energy consumption.

3.

Status

The data collection is fully in progress. A publication with results is

available.

4. Example results

No sample results are available yet.

5 . Comments

A comparaison of the results of this project to the Limmatstrasse apartment building in ZUrich should prove interesting. Like the Limmatstrasse

buildings, the Chaumiere building will be retrofitted. It would be valuable to repeat the measuring after the retrofit. Of interest is the care given to making the sensors and wiring as inconspicious as possible.

Wiring has been concealed in specially installed hollow moldings. Sensors

were located in consideration of occupant furnishings to both minimize the

intrusion and to reduce the liklihood of furnishings distorting the sensor

output. For example, a wall surface temperature sensor subsequently obscured from the room interior by the placement of a massive cabinet would

not permit a realistic representation of the wall's thermal performance.
96
- 97 -

2.12 ZUG APARTMENT BUILDING

BACKGROUND

A three story building containing six apartments has been retrofitted to

measure and demonstrate the energy savings possible given present technologies. The retrofitting consists of a low temperature solar absorber

assisted heat pump, and added insulation and replacement windows to reduce

losses. The first winter of data collection is now completed. The principal

contact for the project is Dr. A. Stebler, Stiftung Sonnenenergiehaus , Zug.
-98-

1 .Objectives

- Evaluate the thermal and economic performance of a solar absorber

assisted heat pump system, as used to heat a multi-family building.

- Develop innovative retrofit installation procedures given the constraint of continuous occupancy.

- Provide a demonstration of a successful application in order to stimulate wide introduction of solar heating.

- Collect data with electronic metering on apartment by apartment variation

of heating energy consumption.

2. Approach / Method

Based on a set of selection criteria, an apartment block was chosen in

Zug. The building is a 20 year old, three story structure with three

3-room and three 4-room apartments. It is a common building type in

Switzerland with several identical buildings in the immediate neighborhood which will permit comparison.

Prior to the retrofit each apartment was heated by a wood burning oven. The resulting large temperature differences between rooms caused condensation damage to the poorly insulated walls.

The building was retrofited with 5-10 cm polystyrol exterior insulation

and a central heating system. The U-value of the building shell, including conventional double glazed windows has been reduced to 0.44 W/m2K.

The low temperature solar absorbers consist of waterfilled black plastic

pipe covering the entire roof as can be seen in the title photograph. A

water to water heat pump extracts heat from the solar heated water and

provides water at 50°C to each apartment for space heating. Figure 35

diagrams the system.
-99-

i Low temperature collectors (H3m2

)

2. Heat pump (2 speeds 7,5 KW)

5. Combustion chamber,

boiler and pump

Fig. 35 Zug Heating System Diagram

3. Status

All the retrofit work has been completed. Results for overall energy con- sumption are available. Measurement will continue in order to get more

precise information on the following:

- Individual apartment energy consumption

- Effectiveness of the heating system regulation

- Operational cost.

4. Example

Due to the added insulation the heating load has been reduced by 50 percent, or a savings of 5000 liters of oil per year. Initial estimation

from the first six months of the solar system operation indicate oil

consumption will be reduced by an additional 4000 liters/year compared to

that which would have been required. Electricity consumption by the heat

pump in bivalent operation is expected to equal the prevously used electric boiler's consumption.
-100

By adjusting the system to the different outside temperatures, electricity consumption could be maintained at between 140 to 115 percent of

preretrofit use in monovalent mode.

5. Comments

The principle benefit of this project has been the demonstration of the

major reduction of oil consumption possible through retrofitting a build

ing using present technology.

An important aspect of this project is the informing of occupants of the

energy consumed by their individual apartment. This feedback along with

information on how to reduce energy demand, is expected to initiate substantial overall energy savings.

A valuable follow-up experiment would be to retrofit one of the neighbor

ing similar buildings with a set of passive solar elements, such as a retrofit Trombe wall or attached greenhouses integral with the balcony

construction. Such a parallel study would provide valuable data on the

occupant satisfaction and cooperation as well as energy and economic

performance of various retrofit strategies.

6. Publicatons

Schweizerisches Status Seminar Warmeschutz-Fors chung im Hochbau

EMPA, 8600 Diibendorf , Oct. 1980

Schweizer Ingenieur und Architekt, Jan. and May 1981
- 101 -

2.13 LESO OFFICE LAB BUILDING

BACKGROUND

A recently constructed laboratory and office building incorporates a three dimensional multi-story grid of thermally isolated rooms with

interchangeable facade elements . It ’ s purpose is to study the performance

of a range of passive solar design strategies for non-residential as well as residential application. The building is occupied by the Solar

Energy Laboratory of the Physics Department of the Swiss Federal

Institute of Technology in Lausanne. The building was completed in 1981

with testing of the initial passive solar elements scheduled to last

one to three years.
- 102 -

1. Objectives

- Measure, the energy performance of a variety of side-by-side passive and hybrid designs under occupied building conditions.

- Study the interaction of the solar components with the auxiliary , heating system.

- Provide monitored performance data for validating mathematical models.

- Enable extrapolations from the measured data to be made, as for

example, for different climate conditions and for other building

designs.

2. Approach

To allow simultaneous measurement of a variety of passive and hybrid

designs, the building has been divided into nine thermally separated

spaces. Each of the three isolated floors is divided into three isolated zones. The long axis of the building runs east/west so that each

space faces south. Below are the plan and section of the building.
-103-

To assess the performance of passive systems, various modes of use are planned:

- auxiliary heating on, rooms occupied.

- auxiliary heating on, rooms unoccupied.

- auxiliary heating off, rooms unoccupied.

These various modes allow the performance of the building and passive

systems to be evaluated integrally with the influence of both occupants

and the auxiliary system, or independent of one or both of the latter.

Data collection will be controlled through a central computer with high

level language programming capabilities. Sixteen peripheral units contain

54 measurement channels and four actuating channels can be used to collect

data on temperatures, electric voltages, mass and energy flows and

working times. Ten of the peripheral units will be dedicated to the building, one of the units will be dedicated to an outdoor testing facility

and the remaining five units are for future expansion. Data will be

stored on magnetic tape with analysis deferred to the Physics Department

Computer or the Central Data Processing Computer.

3 . Status

The building has just been completed and is now occupied.

Instrumentation is in progress.

4. Example Results

Not yet available.
-104-

5 . Comments

This project is an important experiment for Switzerland because it will

be the first effort to measure the energy and comfort performance of

passive and hybrid strategies in the context of an office environment

rather than a residental environment. It is of course true that the

occupants of the building, being solar researchers, do not represent

a completely unbiased, representative sample of office workers.

Nonetheless, energy and comfort performance can be normalized

to various occupant use scenarios. To this end, the dedication of

the occupants provides the advantage of experimenting with various modes

of use not possible in a conventional office building situation.

References

Groupe de Recherche en Energie Solaire, "LESO: Le Laboratoire d'Energie

Solaire" , Department of Physics, Case Postale 1024, CH 1001 Lausanne,

June 1980
-105-

Basel-Binnmj Qottingvn

Beznau

Zorich -Kiotan OOsgen StQallen

Santis Wynau

Chasseral

La Chaux-de-For

Luzern Neuchdtel

La FrAtaz Bern-Liebefeld Weisstluhioch Pilatus Altdorf Scuol jChur-Oomat/Ems

Epgelberg Davos Payerrre

Interlaken Gutsch

Disentis/Muster Hmterrhem Moieson

Changins Jungfraufoch Samedan -St Moritz Piotta Adelboden

La DOle Ulrichen San Bernardino|

Montana Corvatsch

-Monti XocaroAMagadmo

Zermatt Lugano

Grand St Bernard

2.14 AUTOMATED CLIMATE DATA COLLECTION NET

BACKGROUND

In 1973 the SMA (Swiss Meteorological Institute) produced a study

showing the necessity of a net of automated meteorological stations. The

study convinced the government of the need and project development started in 1973. By 1978 a net of 20 stations were in operation providing

data for weather prediction, agricultural planning, small aircraft routing, etc. Since its inception, the need for climate data for predicting

building energy consumption has become apparent. For solar design, measured

hours of sunshine and computed global and vertical south, east, west

and north solar radiation are available for 60 locations through the

Technical Meteorology Section of the SMA, headed by Dr. P. Valko.
-106-

1. Objectives

- Build an automated network of meteorological stations which provides com- plete and precise data with a high rate of data transmission independent

of qualified personnel at the site.

2. Approach / Method

50 ANETZ stations have been built jointly by the Swiss Meteorological

Institute and the Agricultural Research Institute. Ten more stations

are planned. Automatically collected data include: air pressure, air

and ground temperatures at various depths (the latter at selected

stations), humidity, wind direction and speed, precipitation, sunshine

duration, illumination (lux), horizontal global radiation, evaporation

(mm water evaporated from a 500 mm2 water surface per unit time), and

incidence rate of lightning. In addition some visual observations can be added such as information on cloud types and cover. Ten of the

stations are planned to also measure direct solar radiaton.

The whole system cost circa $ 2.5 million. Annual operating costs

amount to circa $ 225,000.

All the measured data are transmitted to a central computer at ten

minute intervals, then directly transmitted to the user institutions.

The main computer of the Swiss Meteorological Service in Zurich makes

initial validation to assure that the data are within range, and transforms the data into the users format; access is provided to other users through the ETH-Z Central Computer. A second parallel computer in

Locarno-Monti , provides a back-up to the Zurich system.

The title page shows the distribution of the stations. The stations'

positions have been chosen in order to get a representative overview

of the Swiss climate.
-107-

3.

Status

The ANETZ system has been in operation since 1978 when 20 stations were

installed on a trial basis. In 1980 approximately 50 originally planned

stations were completed. In the near future 63 stations will be in

service.

4. Example result

ANETZ system results are continuous files of weather parameter values in

metric units stored short term on on-line disks and long term off-line

to the SMA computer.

5 . Comments

With the implementation of ANETZ, Switzerland has the most dense meteorological measuring system in the world.

The several laboratory and university test cells and instrumented buildings with meteorological stations provide a useful complement to the

system.

For simulating the energy performance of passive solar buildings it

would be very useful if ANETZ collected direct normal solar

radiation data thus permitting determination of direct and diffuse

radiation.

6.

Publications

SMA, "ADOC", Swiss Meteorological Institute, Krahbiihlstrasse 55,

8044 Zurich, Switzerland
- 108 -

*
-109-

2.15 OCCUPANT FACTOR / AIR CHANGE RATE DATA BASE

BACKGROUND

This project is actually a continuing series of projects begun in 1975

by EMPA with Dr. P. Hartmann the principal contact. The goal of the

research is to establish more precisely the rate of air change which

actually occurs in occupied dwellings. The heat lost due to deliberate

or inadvertent ventilation can equal the heat lost by transmission

through a well insulated building envelope. When occupants partially

open windows, the heat loss by infiltration overwhelms that lost by

conduction. Yet in calculating a building's energy performance the

number of air changes per hour is often only an "educated" guess. This

project is directed at informing this best guess process.
- 110 -

1. Objectives

- Measure how the air change rate varies as a function of occupant behavior (window and door openings) relative to climate, building, and

apartment type, and location in the building.

- Record occupant behavior based on observation of a sample of buildings.

- Establish generalizable air change rates for comparable buildings

based on observed behavior and the previously measured effects of

such behaviors on air change rates.

- Develop statistical correlation functions relating occupant variables,

building geometry variables, and climate variables to air change

rates. (While the sample size is too small to provide an acceptable

confidence level, it does provide an illustration of how such functions could be generated given a larger sample size).

2. Approach

The first objective, measuring air change rates as a function of various

parameters, was accomplished by actual measurements of a sample of

dwelling types. This sample included: two elevator apartment blocks with

measurements taken in two two-room flats, one three-room flat, two five- room flats and one 5 1/2-room flat; three single family houses, one row house, one office in a five story building, and one two-room full scale

test cell. Two measurement approaches were taken. First, a window and

door schedule were compiled and a sample of these components was measured for insitu air tightness. This was accomplished using the conventional procedure of installing a plastic film over the component, pressurizing the space between the film and the component with a small blower,

then measuring the pressure difference between the pressurized space and

the ambient pressure for specified airstream volume flow rate from the

blower.
IllSuch data provide an improvement in estimating airtightness versus

the conventional approach of merely using crack length. The second,

detailed approach was to evalutate the air change rate in various rooms or combinations of rooms in each dwelling using the conventional tracer

gas decay measurement technique. NLO was used rather than SF, which is

z o commonly used in the U.S.

Plastic film

Window frame

Window to be tested

Temporary frame

for the film

Ap pressure dif. guage

Fig. 37 Window Insitu Measurement
- 112 -

The second objective, providing data on occupant behavior based on observation, has been conducted by observing and systematically recording window sash and rolladen * positions for a sample of apartments in a development in Volketswil for two days and in Zurich in the Limmatstrasse apartment block for one day. A more intensive study involved observations of

two apartment buildings. During 65 days between October 1977 and April

1978 window positions and rolladen positions were recorded at 10 00 h and

16 00 h for each of the 24 three-room and eight one-room apartments. For

six days during this period observations were increased to half hour intervals. To estimate window positions when the rolladen is lowered, as at night, occupants were interviewed. An alternative to inverviews would

have been to take infra-red photographs. Such photographs clearly indir

cate whether or not a window is open behind a closed rolladen.

The third objective, estimating air change rate is being pursued with

a simple computer program which reads observation data on window

position, assigns hourly infiltration rates based on the previous tracer

gas experimentation with similar apartments, and calculates daily infiltration and resulting heating energy values.

The fourth objective, developing a set of correlation functions, involved

a standard curve fitting procedure to generate values for the constants

A, B and C in the following equation of physical parameters:

n

L = [A + (B • dT) + (C • v

2

)] (1)

where:

n^ = number of air changes per hour

dT = inside to outside temperature difference v = wind speed in m/s at a reference height of 10 m.

* A rolladen is a horizontal slat blind in a track outside a window.

It is raised or lowered from the inside without opening the window.

When raised it rolls into a box built into the wall at the top of

the window
-113-

The frequency of a window being open, "f" is calculated according to

equation (2)

f = K (1 - k

2

• dt - k

2

• v) (2)

where:

K = a constant

k

1 = a user function correlated to temperature difference

= a user function correlated to wind velocity.

The window opening factor "f" is then superimposed in equation (1). n

L = f(A + B x dT + C x v) (3)

3 . Status

Step one, in-place measurement of building envelope components and tracer

gas analysis of various window and door positions in a sample of apartments, has been completed and the documentation published in several

sources. Step two, observing and recording occupant behaviors, was com- pleted in 1981. Step 3, observations and tracer gas measurements was completed in the spring of 1981 for the apartment buildings near EMPA

and a detached house in Maugwil. The computer program is operational. The

final step of generating correlation coefficients for calculating air

change rates is also in progress. Success is dependent on a larger sample

size in the future in order that coefficients be more statistically reliable.

4. Example results

To illustrate the result obtained in step 1 where air change rates were measured in a sample of apartment types, the data for the five-room apartments

are presented. The floor plan and window and door crack lengths are shown

in the figure 38.
-114-

Window

Crack

Lengths

6.85m

3.89 m

3.89m

6.85m

t

Floor Area 97. 8 m

Volume 245.0 m

Fig.38 Apartment Plan

The number of air changes occuring in the apartment is strongly affected

by the wind characteristics and window and rolladen position. Whether

doors between rooms in the apartment are open or shut is also a lesser

factor. The two curves of the tracer gas decay rate shown in figure 39

indicate how the air change rate of the living/dining rooms is affected

by change in wind direction and velocity.

C[%3

Fig. 39 Air Change Rate Versus Wind Direction and Velocity
-1 15-

Similar ly , the window and roll blind position affect the number of air changes as shown in figure 40. Even with the casement window only open 10 cm and

the rolladen lowered the air change rate increases by an order of magnitude

over the closed window. With the window in the 10 cm open position and the

rolladen raised, the air change rate increases by one air change per hour.

With the window completely open the air change rate increases by a factor

of 60 from the shut window.

Tracer gas concentration

C [%]

1 ) Window shut / Roll blinds raised

2) Window 10 cm open / Roll blinds shut

3) Window 10 cm open/ Roll blinds raised

4) Window opened to 45°/Roll blinds raised

5) Window opened to 907 Roll blinds raised

Wind

/

dT = 13 — 17°C

Number ot Air Changes

Determined From Decay Rate

0.15 tf]

1.5 h" 2.5 h" 6 0 h' 9.0 h

Fig. 40 Tracer Gas Decay Rate Versus Window Opening

The effect of interior door positions on the air change rate of rooms given various window positions, is partially shown in the figure 41.

From the various combinations it is apparent that door positions are less of a factor than wind speed or even a slight opening of a window.

More measurements are needed, however, to quantify the moderating influence of closed doors given partially or fully open windows.
FIG.

41

AIR

CHANGES

RELATIVE

TO

WIND

AND

WINDOW /

DOOR

POSITIONS - 116-

CT> ro r» in rH CN CN

H

O

O' in CN co O'

m O' o co ro CO TJ o • • • • • • • 1 • 1 • • H 2 • • • o O o rH rH O H O O O O < u £1 O O CN rH

&H fl iD CN o in

co

a • • • • <c 1 3 CN o CN rH 2 -H ft 1 1 i a ft o o ro O ID in o Eh fO in o CN • • • • « CO ft

(0 • • CN 00

O rH CN 00

W 1 O rH o CN 3 -M ft 1 1 1 1 1 ft ft i i S*>’ o in O in o O o in in in o o o o • • • • • • • • • • £ • • • r* CN r* r» o o CO ID ^ CN l-> r- rH ID rH rH rH rH CN CN

Eh 1—1

(N rH c0

•H

4-> o

(U i £ g SB M N \ 3 w S 3 \ g \2 g 2 2 CO 2 2 2 2 2 3 co 3 2 Q 3

0) *

•HO in ID o

r- CN• in• in in• 00 in• 00 CN • • 00 in • •

0)

H CM • CN

rH CN 00 CN

m rH

m co

H ^ > 0J < > »Q

03C

•H c 3 O' • 01 c • P • ft G •H 4-1 3 4-> 0 • 0) > 3 • JC 3

XJ £ • •H £ £» C0

A

g

a OJ

O +J CO 3 Cfl 0 CO P 3 £ X3

r\ • 0 •H £ c XJ co 0J CO 4J 4-> o rH ft (0 •H d) rH S H 3 • rH CJ rH CO 3 0 £ £ V - OJ £ 3 * d> XI

(0 0)fto

0) 3 cu O'

O Cfl CO OJ

O CO c

JC

n

C

m i—i 3 CO X) •H

to

CO CO 3 •H 5T 3 CO

C

U 3 > s

T3

U £1

U -H 5 § 0 3 4J G rH rH s 00 Ofl £ <u

XI d) Oh >i a; rH o3 8 c •H £h ft 3 t •k < CO •H Lj •H 3 P 0) 0 +J • < c VH 3 o 3 0) CO > * 30 CO O

qj pH 10 0)

U

C £ m

a ft

a o

o3 £1 o

o8

O 3 * 0 0J 0 ft

10 8 0 8

10

(0

GU

Cfl

C OJ X) 0 CO c ft CO

U

M

(/) 0,) 08 •H CO

C T3 0) 0) A ft

M OJ ^4 OJ

pc

<u 1

45

(0 50 8Q < £

(0

•H2 8 & s l 2 20

nd 8 3 3 0 0 a

u

G

to rH (0

A 4-> 3 rH

O

O rH

O rH o

rH

p •H

M

h 3 O rH

O ^4

u < rH < < rH 0 ft

O <C ft

Q < Q <

T3

OJM

to3

OJ T3

as8

OJ sA 0 CO

ft

ao

ftc

•H> I PM

ns a*

<unH 4-1 +J C C 0) w a
-117-

The second step, observation of occupant behavior relative to window

opening, is currently in the data analysis phase. The pilot study provides

an example, however. Figure 42 illustrates window and rolladen position

for 22 apartments, all occupied. The data from 06 00 h to 20 00 h is

statistically complied from analysis of photographs taken at 15 and 30

minutes intervals for a Wednesday and a Saturday in mid winter. The data

for the period from midnight to 06 00 h and from 20 00 h to midnight are interview statistical data,

Window shut/roll blinds shut

\\\W \\\\\ V\ vi \ \\N

v v y v )

7_/^’^vk\\\\\N

, z

- . . . . / / / / / / //////)y y y y > y

'///Window shut/roll blinds ^^///_/// \\ (

^ - ^ ^ / / / / /

/

\\\\W\\N\\ Y/'/V/yV/V//////

00

Bed Room

24°o

Living Room

Fig. 42 Window and Roll blind Use Based on two Days of Observation and

Occupant interviews
-118-

Table 4 illustrates the calculated effect of occupant positioning of

windows and roll blinds on air change rates and resulting make-up air

heating requirements. The schedule of window and roll blinds positions is

statistically determined for each day from observations of two low rise

apartment blocks similar to those previously studied. Based on the measurement experience of the previous study, occupied room air change rates were assigned for various window and rolladen positions as follows:

Configuration Factor multiplied by

unoccupied room air , change rate

Window shut/roll blinds down

Window shut/roll blinds up

Window open/ roll blinds down

Window part open/roll blinds up

Window full open/roll blinds up

X 0.6

X 1.0

X 7.0

X 10.0

X 30.0
TABLE

4

AIR

CHANGE

RATE

AND

RESULTING

HEAT

LOAD

CALCULATED

FROM

TEMPERATURE,

WIND

SPEED
- 120 -

5. Comments

Because air change rates can represent such a large percentage of heating

requirements it is imperative to have quantitative data on actual air

change rates which occur in occupied buildings. With even partially opened

windows the infiltration heating losses overwhelm transmission losses

through the building walls and roof. Realistic analysis of expected energy

savings from various retrofit or new design conservation strategies should

recognize occupant behaviour factors if, in fact, the analyses are to be

realistic. This project is valuable because it defines types of behaviors

and quantifies their duration based on both observation with photographic

documentation and interviews with the occupants. This information is then

coupled with measured data from the tracer gas studies on how the defined

behaviors alter the rate of air change in various types of dwellings.

Such data will be helpful for a forthcoming building code decision whether

mechanical ventilation systems should be mandatory for new residential

buildings

.

No one should infer from the results of these initial studies that sufficient data are now available to accurately correlate air change rates to

occupant behavior. Two major areas of work need substantial amplification:

First, the completed studies could only evaluate a sample of possible window and door positions and the resulting rate of tracer gas decay.

Additional configurations which should be systematically studied include:

windows open in bedrooms on opposite sides of an apartment and

the effect on the air change rate of the remainder of the apartment rather

than the bedrooms themselves; windows open in a given room and all doors

open between rooms and the resulting air change rate of other rooms upwind and down wind from the room with the open window. One means of

conducting such analysis would be to inject and measure tracer gas decay

rates in all rooms simultaneously. In addition to determining air change

rates, the air temperature profile for each room should be recorded. The

influence of the thermal mass in a room on air temperature decay rates

when a window is open needs documentation.
- 121 -

A second category of needed research is statistical correlation

of occupant descriptors and window and rolladen use. Example possible

descriptors include age, education level, smokers or non-smokers, and

number of working adults in the family. Similarly, statistical analysis

of the correlations between wind direction and speed, temperature, and

window rolladen position on air change rates are needed. As mentioned,

an initial correlation is under developement , but a larger sample size

is needed.

Once such research is completed, the implications of the data should be

interpreted into example building designs which recongize occupant

behavior and minimize the consequences of such behavior on heating demand.

References

(1) EMPA-Report Nr. 34020: Luftwechselmessungen in nichtklimatisierten

Raumen unter dem Einfluss von Konstruktions- und Klimaparametern;

(Bericht 1) Diibendorf, Dec. 1977

(2) EMPA-Report Nr. 36620: Luftwechselmessungen in nichtklimatisierten

Raumen unter dem Einfluss von Konstruktions-, Klima- und Benutzerparametern; (Bericht 2) Diibendorf, Mar. 1978

(3) EMPA-Report Nr. 39400 b: Luftwechsel in Wohnbauten, FensterLiiftungsverhalten der Bewohner zweier Mehrfamilienhauser in Abhangigkeit vom Aussenklima; (Bericht 3b) Diibendorf, April 1981

(4) EMPA-Report Nr. 39400 c: Luftwechsel in Wohnbauten, LangzeitUntersuchungen betreffend Luftdurchlassigkeit und Luftwechsel

eines Einfamilienhauses ; (Bericht 3c) Diibendorf, April 1981

(5) Hartmann, P., Pfiffner, J., Bargetzi, S.: Luftwechselmessungen

von ausgewahlten Wohnbauten in der Schweiz, Klima- + Kalteingenieur

,

Heft 3, (Kurzfassung Bericht II) (Available in English) 1978
122
- 123 -

2.16 IMPULSE PROGRAM: COMPONENT TESTING DATA BASE

BACKGROUND

The Swiss government is sponsoring an extensive program to measure

the performance of building components in conjunction with a training

program for building design professionals involved in energy conserva- tion retrofit projects. In the measurement program, building products

used in energy conservation are tested. Replacement windows and insulation materials are two such example products. Testing is done at

EMPA under Mr. R. Sagelsdorff, at EIR under Dr. P. Kesselring, at EPFL

under Dr. C. Roulet, and at ZTL under Prof. F. Oezvegyi.
-124-

1. Objectives

- Determine the important properties of each product relative to its

intended use.

- Establish realistic comparative values through normalized testing.

- Exclude inappropriate use of products.

- Collect product information to be used within the Impulse Program's

training courses.

2. Approach / Method

To ensure comprehensive results, it is important to test as many products as possible. As an inducement to have their products tested by the

EMPA and the ETHL, manufacturers pay only 20 percent of the testing costs

the other 80 percent are paid by the government.

Manufacturers can use the product's test data and ratings for publicity

upon completion of the testing program.

The products are divided into the following groups:

- Thermal insulation materials

- Insulating plaster

- Foam insulation

- Sandwich panels

- Vapor barriers

- Exterior insulation systems

- Insulating wallpapers and foils

- Windows

- Pipe insulation

- Solar collectors

- Thermostatically regulated radiator valves

- Heat pumps

Test samples of the products are randomly selected several times a year

at the place of production during the three year measuring period.
-125-

For systems or components of systems not subject to large variation in

quality, only single tests are conducted.

3. Status

The Impulse program started in 1979 and runs through 1982. Some of the

test results are now available. Windows are presently being tested.

By 1982 all the test results should be available.

4. Example Results

Figure 43 shows a list of comparative values for Group 1:

Thermal insulation material.
- 126 -

COMPARISON

TABLE

INSULATION

DENSITY THERMAL CONDUCTIVITY

c

0

•H

(/)

C/J X

ftc

( INORGANIC

FIBER)

&

Required

value

(SIA

Norm

279)

Measured

value

Required

Measured Moisture

Transm:

Expansion

due

tc

Moisture

pX

CO0

>H

(0

(0<uP

!

u

kg/m3 kg/m 3 W/m*K y %o N/mm2

Product A 24 + 3.6 32.5 0.040 0.040 y *d=

18 m — —

B 24 + 3.5 24.5 0.040 0.037 4.4* — —

C 180 + 27 175.8 0.040 0.045 3.1 0.35 0.12

D 110 +16.5 134.6 0.036 0.042 2.9 0.05 0.067

Range of Application

Wall Slant Roof Flat Roof Floor Ceiling

CD 0 d d G

•H •H O

CO CO •H p C X

0 T) Cfl CD d a 0 o

4-> 0 ip p CD CD d i—

1

p •H 0

CO X 0) 0) 0 0) CO G C •H o <d -P p

IT) IT) d 0 pi P IT) <d CO u s G IT) 0 X

T—\ rH •H •H Pi a PI CD P P 0 rH d CO ft

1 •H CO CO 0) IT) P> g * •H 0 •H c x d

a X Pi X g g C CD o pi CO CO 0

c g c a 0 !0 IT) QJ o o IT) c .—

.

u —

0 0 0 pH p p a Pi s s CD s CT) IT) rH M a ft ft •H > •H 0 IT) CO 0) d ft ft 0

ft p C 0 G X X u s CD P p CD •H ** CO CO CO IT) •H

rd G (0 • tp S CD ID > ip CO d G c £ rH p - ; i—

1

O rH G G a 0 Pi d d O 0 G iH iH H •H H co

' 0 •H 0 O O 0) 0 CD C £ X o G 0 s s

ft p G 0 r. 0

CO x CO CO ft X 0 cd Pi •H O (0 IT) fO

CD O o

'

*

J C id G * P p P c H rH H co (0 G ft G G c G d c u u u •H X G E c • » 0 G G O G O O 0 0 CD 0 p d

O id O H • P cn P H H •H •H •H •H •H •H pi •H G fi c IT) •H 0

0 G 0 x x p> p> pi pi (0 p> O o 0 0 IT) X PQ 4- « •H H •H d d IT) (0 IT) IT) 1—

1

IT) XI 0 id 1 id p p G G rH rH 1

1

1—

1

rH rH •H iH P p p d

rH rH T) •H ‘v. o • 0 0 B 0 0 0 0 0 0 p> 0 0 o 0 i 0 0 d o x X X 0 0 CO CO CO CO co CO c CO 0 0 0 IT) G co O co 0

X X G p p G G G G G C CD G rH 1—

1

1—

1

Q 3 G s c s

w ft H o o H H H H H H > H ft ft ft X Z H H

Product

A • • • •

B • • •

C •

D • • • • •

Fig. 43 Example Product Data from the Impulse Course
- 127 -

2,17 A SIMPLIFIED METHOD FOR CALCULATING HEATING DEMAND

BACKGROUND

A simplified calculation procedure for estimating residential energy

demand has been developed by J. Gass of the EMPA. The procedure takes

into account internal gains from people, solar gains, and the building

mass. The method uses coefficients generated from computer runs for

specified typical Swiss houses. Multifamily and single family building

types are included and calculations are based upon a variety of different

Swiss climatic conditions.
-128-

1. Ojectives

- Develop a simple procedure for calculating the building energy requirements considering solar gain, building mass, and occupant factors.

- Calculate solar data needed by such a procedure from existing solar data.

2. Approach

Development of the calculation procedure required the following steps

each of which will subsequently be explained.

1) Develop a simple means of estimating intensity of solar radiation

from hours of sunlight.

2) Define representative building types for computer modeling

3) Define occupancy gain profiles.

4) Computer model the auxiliary heating requirements of the buildings

considering the above factors.

5) From the computer analysis determine the percentage of usable solar/

internal heat.

1) Estimate solar radiation

A means of estimating solar intensity was quite important because in

the Swiss climate solar gains can equal 10 to 50 percent of the magnitude of the heating load of a building. Switzerland now has a dense

net of meteorological measurement stations but long term records of

data exist for hours of sunlight only at sixteen stations and for

global horizontal and diffuse solar radiation only at three stations.

Building energy analysis requires data on radiation incident on vertical surfaces. A means was therefor needed to determine solar radiation incident on vertical surfaces from data on horizontal surface

irradiation and hours of sunlight. The following method was used:
Global

Vertical/

Global

Horizontal

[%]

-129

For three stations data were assembled on global and diffuse radiation on the horizontal surface and on the duration of sunshine. A

correlation function between the global radiation and the duration

of sunshine was calculated for each month. Correlation functions

for two stations in very different climates (south and north of the

alps) were similar enough that one could assume they are valid for

all regions in the country below 800 m. At one station global radiation

on vertical surfaces oriented to the four cardinal points was also measured. These measurements were used to determine the ratio between the

diffuse radiation on the horizontal surface and on the different vertical

surfaces. For lack of better information one has to accept that these

ratios are generalizable until data from other stations become available.

Results are shown in figure 44. The distribution of the direct radiation

was then easily calculated with the help of the distribution ratios for

the diffuse radiation. Monthly distribution ratios for the global

radiation were then generated for the two other stations.

South Monthly ratios between the global

radiation on a vertical surface and

on the horizontal surface (mean values over ten years

)

Davos

Locarno

Zurich

Fig. 44 Global Vertical to Horizontal Solar Ratios for Three Cities
-130-

2) Define representative residential building types:

To generate building energy requirement data, four different

buildings, shown in figure 45, were defined which were deemed representive of a good cross-section of the Swiss stock of residential buildings.

12- Story Tower Building Multy Family House

(48 appartments ) ( 12 appartments

)

20,0m

T T

H*.S§h o

o<VJ

r//77////,\ V7/77/777

>7777777777,

1 35

:in mi

0m

ra (id

rn T dh. T nl

Multy Family House

(6 appartments)

> —

EO LTi] mi

n i rr.

Single Family House

777/7///.

7.7777777777777777777777

E, hcvj ~”777/

/

Fig. 45 Representative Swiss Housing Type Designs
-131-

3) Define occupancy heat gain:

The heat gain due to occupants was estimated at 10 MJ/person day based

on experience from other projects and the literature.

4) Mathmatically model building heating requirements:

Because free heat (solar and internal sources) was of special concern,

monthly values were calculated for heat loss, the amount of free heat

including its degree of utilization, and the net heat requirements.

Combinations of the following variations were modeled: four building

types, five climates, three insulation levels and three window areas. Five climates are characterized in table 5 by their degree days and

vertical south solar radiation.

Table 5 Four Swiss Climates

Location degree-day * Radiation on south facade

°C day kWh/h

Zurich 3641 917

Bern 3647 910

Geneve 3035 979

Davos 5887 1059

Lugano 2596 1016

*) Heating degree days in Switzerland are calculated based on no heat

being required above an ambient temperature of 12°C. Below this

point, the number of degrees is based on the difference between an assumed room temperature of 20°C and the average ambient temperature for the day.

5)

Determine usable solar and internal gains:

Given the modeled building heating requirements for the four

building types, a factor (3 was determined for relating the free heat

to the total building heat loss. The heating requirement can be ex- pressed with the following equation.
-132-

^net ^loss ^ ^ ^

id yeb no8i9q\LM 01 dB b9dBinxd89 bbw adnsquooo od 9ub nxsg dB9d adl

This term 0 contains the influence of solar radiation and the normalized

, 91UjS19jil add DUB 8J39

i

9uJO non ajini 134*3 1,u

user influence. It is dependent on the climate and on the building type.

3. Status

sio9qa

: 8l09ffl9iiup9i gnxdsad g. To esw ( 89311108 isaiadax

,ud X9bom yl

£ i 02 ' ^ B3ll *

bM (A

d£9ii To dnuoms add aaol dead 10I boiBliolfio 9 . sw aauisv ylii-uoin

The simplified calculation method has now been completed. As more measur-

. adi a d&9n dan 9dJ dxib t noxJ8Sxxxjxi io nigau ajx guiouxjiu

ed data from instrumented buildings become available, the calculation

gnibJ w anoxjBi oi.or hiej - ,TT 7 procedure will be further tested for its validity and the coefficients

further refined.

4. Results

Analysis of the computer data showed a strong dependency between heating

energy, and the volume of the building and its insulation level. A parameter

containing both insulation level and volume was therefor determined.

The so called G-factor is the specific heat loss per unit volume and

temperature difference. It is calculated as follows:

G = I. (A. • U. / V) + 0.34 • n W/m3 ill K (2) ore TAde msa

Where: A = building envelope area

U = building envelope average insulation value (W/m K)

V = building volume

n = number of air changes per hour

i = subscript for each building envelope material.

The calculated values for 0 are shown in figure 46 for the climate of

Zurich, for all cases with medium window size (33 % of the south

facade and 16 % of the other facades. All the calculated points

fall within a band of ±2 %. For other climates the mean curve shifts downwards as degree days increase as seen in figure 47.

: anx£j I6ni9dnx bns iBloa aldsau anxmiadaG

mol add iol adn9fli9ixup9i gnxdBad gnxblxud b9l9bom add n9vx0

Js9d 99i 1 add gnxisiai 10I banxnnsdab atw 0 lodost b ,aaqyd gniblxud

-X9 ad ubd dnamaxxupai gnxdBad 9dT .aaol dsad gnxblxud Ifidod oJ

.noxdfiupa gnxwollol 9rid ridxw baaaaiq
-133-

Fig. 46 Percentage of the

o

<3-

7c

supply of usable free CO.

heat loss as a function 30 -

of the specific heat

loss per unit volume

in the climate of Zurich 20 -

0.5

G- Value EW/m3 K]

In using the simplified calculation method the following should be noted:

- The method only applies to heating (not usable for air conditioning)

- Heat gains reduce these losses by a factor (l-{3), which can be

determined according to the G-value of the building and the climate.

- An increase from the assumed 35 percent window area for the south

facade to 45 percent raises the term p by two percent.
-134-

5. Comments

Simple calculation methods for determining heat loads of passsive solar

buildings are needed in Switzerland. Present calculation procedured

are insensitive to the effects of internal thermal mass and internal

heat generation above or below some unclearly establishment values.

This calculation method is a valuable step in the direction of establishing such a method. The coefficients are based on a few typical example

house types, however, and a statistical data base is needed for the performance of houses deliberately designed to take advantage of mass and

internal gains.

6. Publications

Gass, J., S

Gass, J. "Simplified Calculation Method for Residential Energy

Requirements", Proceedings of the International Energy Agency Conference , Berlin, West Germany, 1981.
- 135 -

The preceeding selection of research

projects provides an indication of

Swiss research priorities. In this

closing section these directions and areas of concentration will be examined

in the context of an organizing research

framework. By locating research projects in a framework then examining

the framework it is possible to determine the breadth and depth of re- search by subject, type of research,

and type of application. Profiling

a country's research program helps

identify important linkages among

projects within the country, possible linkages to project areas in

other countries and by virtue of

the gaps, important subject areas

for future research.

3.

OBSERVATIONS
-136-

The research projects reviewed in the previous section were grouped by

characterization of research activity, e.g. mathematical simulation,

instrumented buildings, etc. In this section these groupings will be

placed in the context of a larger and more detailed framework, diagrammed in figure 48. The above mentioned research activities

can be more precisely defined by application types, e.g. residential,

institutional, mixed, etc. The resulting table of projects can be

filled in for any given individual subject area of a given category of

research. The categories are here defined as component research,

systems research, and support research.

An inventory of Swiss building energy research using this framework is

currently in progress. The ongoing or completed Swiss research projects

are being entered in the framework. In an overlay framework, projects in

other countries are being identified. Where gaps occur in the Swiss

framework the other countries overlay can then be examined to see if

Switzerland can profit from work done elsewhere. Similarly, redundancies

between Swiss and other country research subjects indicate opportunities

for each country to share results with the other. Finally, subject areas which have no project entries will be examined to determine if important

opportunities to conserve energy are not currently being explored and

warrant a shift in research efforts.

Based on the work completed to date on this effort, general observations

will be presented in this closing section on the present priorities and

possible future directions for energy conservation research. Comments

will first be presented on subject areas within three categories:

component research, systems research and support research. Comments will

then be made on activities relative to type of research approach, and

finally on different applications.
Research

Typ./

Applications

Subjects

Categ

-137-

Building Envelope Research

C

l. ComponentN

Research )

II. Systems 'N

Research )

M. Support

Research

A. Bldg. Shell A. General A. Climate

B. Windows B. Direct G. B. Bldg.Phys.

C. W. Accessories C. Indirect G. C. Materials

D. Selective Surf. D. Sunspace D. Occup. Factrs.

j

. E. Thermal Stor. E. Isolated G. E. Economics

F. Controls F. Mixed G.

G. Hybrid

H. Conservation

c>ubject

e.g.1.E "I \

Therm. Stor. J ^ — Researc

. Concpt

Gener

h Activitie

l. Mathm. 3

. Simul.

!S ( 1- 5 )

V Proto- L

Type

k Instrum, i Bld'gj. Design

Tools

a.) General

„ b.) Resid. co

'£ c.) Commer

o

% d.) Instit. <i

e.) Mixed

i f.) Multi Bldg

Fig. 48 A research Framework
- 138 -

RESEARCH CATEGORIES

Component Research

Much research has been completed in various aspects of the building shell.

Component testing and coursework preparation was completed for the Impulse

Program on such elements as insulation systems, window types, and exterior

surfaces. Work has been undertaken on the subject of selective surfaces

including both simulation and instrumented prototype test cell applications.

A start has been made in the areas of window accessories, controls, and

thermal storage, primarily at the EPFL.

Suggested future work in component research should include research on the energy implications of architectural form relative to heating and to

a lesser extent air conditioning, as well as lighting. The most recent

examples of modern commercial and institutional architecture embody

design and programmatic concepts which require extensive artificial

illumination and air conditioning in spite of Switzerland's moderate

summer climate. Preconceived or preordained geometric forms for various

building types should be rigorously scrutinized for their energy

implications and alternative building forms investigated.

More window research is needed to simulate and measure the energy implications of various window accessories and operation scenarios. The Solar

Trap project is a good example of such research, but similar studies are needed for various passive solar window systems, such as selected moveable

insulation components. Similarly, as new window accessories and new window

glazing systems become available, it is essential to re-examine preconceptions of optimal window area for given climates. This is likewise true as the capability of sizing thermal mass relative to window area becomes more

refined. The intense overheating of the Maugwil test cabins and even the

Solar Trap test cell indicate the importance of the balance between glass

and mass in a passive solar design.
- 139 -

System Research

Most research on direct, indirect, sunspace and isolated gain passive

solar systems has been pursued by the EPFL. Their work includes developing

a simulation model, collecting data from test cells, and instrumenting

occupied houses . EMPA has also pursued various passive solar projects

including computer parametric studies of greenhouses and limited test

cell research. Conservation research has not been as regionally concentrated as passive solar research. Conservation research is ongoing at EMPA,

EIR, EPFL and the University of Geneva. EMPA and ETHZ are foci for the

subject of air infiltration and EIR is a focus for active solar systems and

heat pump augmented combined systems.

A likely and useful future direction in system research would be diversification of the above mentioned geographic and institutional research

subject concentrations. While it may not be affordable to have centers

of expertise on all subjects in all regions of the country, some dispersion

of research involvement is important because locally pursued research is

more likely to become applied locally than is the case with research

conducted in a different part of the country. This is expecially true

given the language and culture differences within the country.
- 140 -

Specific systems research subjects which should be pursued include

limited additional test cell measurement, instrumented building

measurement of direct gain systems, attached greenhouses, and hybrid

systems incorporating new products as they become available (e.g. IR

selective multiple glazing, IR reflective multiple layer foil roll shades,

and latent heat storage elements). Computer simulation work should

continue parallel to mesurement experiments to examine the sensitivity

of various aspects of a design and it's applicability in different

climate zones.

Research on mass walls may be of a lower priority than other passive

systems because of the lack of sun in much of the country. Mass walls

suffer the inherent disadvantage that the absorbing surface, (which

reaches the highest temperature) is immediately behind the glazing, which

is the poorest insulator of the building shell and realizes the greatest

losses, particularly at night. In a climate where solar radiation is a very precious commodity, such reradiation losses are particularly disconcerting. A modest research effort would be valuable to determine the

extent that indirect gain mass wall system performance is enhanced when

complimented with a movable insulation system to sharply reduce night

losses. Mass walls can provide an important alternative solution

to architectural problems. One example is the problem of designing

a building for a north-facing mountain slope with a panoramic vista

to the north and no view to the south. In such a situation, a mass wall

comprising the majority of the south facade would be a valuable counter

to the energy expensive windows capturing the north view. Critical would

be, of course, the extent the slope curtails the number of hours of

sunlight per day.

The subject of attached greenhouses mentioned above is particularly

important because of the widespread interest among architects and

their clients. The minuscule amount of available information on sunspace design in the Swiss climate coupled with the amount

of sunspace building activity make this an urgent research issue.

Research questions include the energy benefit of various configurations,

thermal storage systems, moveable insulation systems, and air circulation systems between the dwelling and the sunspace.
- 141 -

Isolated gain or thermosiphon passive solar space heating systems are

rare in Switzerland. Little if any research has been conducted on the

subject. In a climate with extensive periods of only diffuse solar

radiation, effective system performance requires careful, informed

design. Data and guidelines are lacking. A measurement project of an isolated gain system would be useful and several houses have been

built using this principle.

A variant of an isolated gain system, though very much an active system, is the active facade system being investigated at EIR.

In this system a serpentine of tubing is embeded just beneath the exterior of a concrete wall. A heat pump chilled fluid circulating through

the tubing extracts heat from the sun-warmed surface of the concrete

wall. The wall is heavily insulated from the building interior and thus

in principle performs like an unglazed low-temperature isolated collector.

This raises the issue of mixed systems combined to take advantage of

different solar collection situations (e.g. situations of weather,

orientation or occupant needs). To date much of Swiss research has been

concentrated on single systems considered individually. Research on passive systems acting interdependently is needed.

On the final systems research subject, conservation, it might seem that

little further research is needed given the ubiquituous insulation retrofit

activity evident by the scaffolding and facades partially clad in brightly

colored exterior insulation. Work should be done, however, on developing

concepts which integrate conservation strategies with occupant

behavior. An obvious example situation is the custom of opening bedroom

windows to air out the bedding and the room, sometimes for several hours

during the coldest winter days.
- 142 -

Conservation strategies which recognize this cultural phenomenon should

be explored. One possible design which might be analyzed would be to design bedrooms such that they are easily and effectively isolated from

the other living areas, that the construction is light (though heavily

insulated to dampen sound transmission) rather than massive to minimize

the amount of stored heat lost during the airing period, and that the

heating system is automatically shut off when the windows are opened.

Support Research

Swiss work in the support research subject area of climate measurement is extensive. A major investment has been made in the ANETZ system,

and in the Swiss Meteorological Institute.

Building physics is similarly an intensively researched subject area with substantial continuing research at the EMPA, ETHZ, EPFL, and to a lesser extent at the University of Geneva. Materials research is primarily industry sponsored rather than publicly supported. Many of the tests run at the EMPA, for example, are privately sponsored contracts. Occupant

factors research in Switzerland has been both original and fruitful in

the past. The work on the influence on window opening on air change rates

demonstrates the importance of this subject area. Life cycle costing

acquires a different perspective in Switzerland relative to the U.S. given

the Swiss construction and investment philosophy of longevity. In this

situation, amortization of invested principal is less hurried than is the case in the U.S.
- 143-

Future research is particularly needed in the occupant factors area. This type of research is important because of the magnitude of energy

savings possible on a national level by influencing occupant behavior

and by advancing design concepts which work with, rather than suffer

from the behavior of occupants. The many closed roll blinds and shutters

which can be seen on houses on sunny cold winter days illustrate the need

to consider occupant needs in designing passive solar architecture. Low

energy dwellings are likely to be even more sensitive than conventional

houses to occupant influences, either positively or adversely affecting

the energy balance of the building envelope.

In the climate subject area it would be valuable to collect diffuse and

direct normal solar radiation at selected ANETZ stations. As hourly

computer simulation models become incleasingly used, the lack of such

data on a local level will become a major drawback.

A building physics research topic of particular concern is the issue of

moisture transport through the building envelope. Another largely unknown

area is that of the basic convection mechanisms in the dynamic interior

environment of a sunspace.

Finally, in the subject area of materials research, guidelines are critically needed regarding materials properties and behavior in various possible

passive solar applications. To a large extent, much of the work done

in the U.S. can be used as base data. Materials common in

Swiss construction but uncommon in U.S. construction necessitate testing.

An example materials-related issue is the use of woodframing members in

the construction of site-built solar air collectors.

Experience in the U.S. indicates wood so used is subject to severe long term

degredation. The material performance of wood frame air collectors in

Switzerland is unknown.
-144-

RESEARCH ACTIVITIES

Research subject areas shown in figure 48 can be further classified

by types of "Research Activities", namely: Concept generation, mathematical simulation, prototype development, instrumentation of buildings,

and design tools.

Component concept generation in Switzerland is primarily privately

funded by industry. An example project is the Solar Trap. Concept generation is also evident in architectural design, particularly regarding

sunspace configurations. Example built concepts include moveable roof

glazing to convert an interior sunspace into an open atrium, various means of providing thermal storage, and different summer shading systems

for windows and sunspaces.

Development of simulation capabilities has been well supported with the

creation of the PASIM passive solar network model at EPFL, validation of

DOE 2 at EMPA, development of a radiation model at EMPA, and the development

of several simplified calculation procedures which take into account the

usability of solar and internal gains as a function of several building

parameters

.

Prototype testing (test cell measurement) has also been done at EPFL and

EMPA. This work has been useful in gaining confidence in the validity of

imported simulation models.

The Chaumiere apartment block in Lausanne, the Limmatstrasse apartment

block in Zurich, and the single family house in Maugwil are the three

most important examples of intensely instrumented Swiss buildings.

The density of measurements in each of these examples is providing an excellent data base for examining in detail questions regarding building

energy performance. The five solar houses measured by EPFL are also

useful in refining the technique of collecting data from occupied passive

Solar houses.
-145-

Finally, regarding design tool development and design data generation,

the principal activity has been in the development of course material

for the Impulse Program, and the development of guidelines by the Swiss

Society of Engineers and Architects (SIA) . A number of architecture and

engineering offices are developing their own calculation and design tools.

Methods developed at Los Alamos are becoming popular, though there is a persistant caution in accepting correlation methods unproved in Switzerland's specific climates.

Future research support would be valuable in the form of grants to

designers to generate new energy conservation building concepts, to take

the resulting ideas through the level of construction detailing and

prototypical application designs, and to perform detailed calculations of

the energy performance. The details, physical principles, and energy

performance could be published as a handbook.

Future support is needed in simulation, not so much to develop additional

models, but to develop user-friendly input routines to the already existing

models so that their use becomes possible for people other than the program

authors. While PASSIM, DOE 2, DEROB, and the Frank models all are operational in Switzerland, their use is essentially limited to the few individuals who were responsible for their creation or installation. Development of a simple user oriented and forgiving input language for programs

would accelerate the use of these models in practice. Another needed simulation research task is the generation of design guidelines for various

passive and conservation components based on parametric studies using

computer models and regional climate data, followed by statistical analyses of the data. Examples of needed guidelines are apparent in such

issues as sizing glass area as a function of orientation given regional

diurnal solar asymetries; in sizing mass, given a specified window area and thermal storage goal; and in selecting night insulation systems for

various passive solar design approaches, again relative to the regional

climate.
- 146 -

Furthe r research activity in test cell measurement of prototype solutions

could well be limited to the existing inventory of test cells. Because

the fronts of the cells are relatively easily interchanged with new prototype solutions, it is logical to continue research with the present

facilities. One important example application would be the coupling

of an attached greenhouse to a test cell to validate two zone simulation models, and in general, the performance of sunspaces under con- trolled conditions in the Swiss climate.

Measurement of several of the instrumented buildings will continue. More

important than instrumenting additional buildings is the intensive,

thorough, multifaceted analysis of the collected data, development of

design recommendations based on these data, and definition of gaps in

data requiring future instrumentation of buildings.

Finally, regarding research in the area of developing design tools and

design data, important needed work has already been mentioned in the is- sues of sizing components and estimating the energy benefit of a given de

sign strategy. An important specific task should be undertaken in develop

ing micro computer software for architecture and engineering offices.
- 147 -

RESEARCH APPLICATIONS

Finally, the research activities, discussed in the last section, can be examined by what types of buildings are forseen for application of

the research.

The vast majority of research activity is occuring in the residential

application area in Switzerland. Comparatively little research exists

on the subject of commercial or institutional buildings configurations

and energy implications. Research in these latter two applications is

primarily regarding optimization of mechanical systems both in sizing

and operation. Similarly, minimal research exists on what unique energy

saving opportunities occur with mixed-use buildings (e.g. residential

space built over retail space). Finally, almost no research could be

found regarding analyses of the opportunities for conservation or passive

solar use which exist when buildings are considered in aggregations.

It is the authors’ opinion that the most important area of work relative

to application types, is the re-examination of the energy significance of

the preconceived architectural forms assigned to residences, offices,

shops, schools, hospitals, etc. What is the energy consumption of one of

the recently built Swiss Technical University buildings compared to that

of a residence on some normalized basis? Both fullfill the same environmental requirements to a large extent, room temperatures in the comfort

zone, illumination (schools should require less energy- for this because

they are principally used during the daylight hours whereas homes are also

occupied at night), and provision of fresh air. The objective of such

research would not be to discover the obvious, but rather to emphasize

the value in re-examining alternative architectural forms for society's

various activities.

Research would also be valuable in mixed-building type applications,

particularly concept generation and simulation performance analysis. An

example might be the design of an isolated gain passive solar system

which uses the extensive opaque exterior wall area of retail space.
- 148 -

Retail facilities do not value windows on exterior walls (except sidewalk

display windows). Windows complicate the controlled lighting of goods.

Also, exterior wall area occupied by windows reduces display or shelf area. Solar radiation incident on the opaque exterior wall area of retail space

is therefor largely wasted and could readily be collected (and even augmented by heat from the lighting system) for use in residences built

above the retail levels.

Multiple building applications are another important research subject.

Example multiple building situations in Switzerland include the few instances of regional shopping centers (which are in effect multiple buildings linked by common circulation "halls", city centers (new shopping

centers built in the middle of a town or city), terraced housing projects

which typically step down a hillside, the downtown assemblage of buildings in towns and cities, the office parks of both private industry and

government institutions, and school and university campuses. Analyses

should be conducted on such muliple building situations to identify solar

collection and use opportunities relative to times of space use and space

heating or illumination requirements. Heating and cooling load balancing

should also be explored. A classical application for analysis might be

the enclosure of the main street of a city and the creation of a pedestrian sunspace thereby creating a tempered environment for shoppers

and residents, and a tempered environment for half of all the vertical

building surface area.

Multiple building studies should also be conducted to investigate the

form implications and opportunities resulting from annual cycle thermal

storage solar collection. Such system studies to date have tended to

focus on the optimization of the solar collector/ thermal storage system

considered in isolation from the total conceptualization of the siting,

form, and use mix of the building served. Improved integration of the

components with the architecture and planning could result in enhanced

economic performance.
- 149 -

Conclusion

Energy conservation in buildings is a high priority research subject

in Switzerland. To date investigations have been concentrated primarily

in the subjects of insulation of the building envelope and in active solar

heating systems. More recently, research has been begun on the subjects of

passive solar energy use and combined solar and heatpump systems. Housing

is the building occupancy type most frequently researched. Conservation

measures and active solar systems have been studied in conjunction with

multi-family housing, passive solar systems have been studied in conjunction with detached single-family housing. In the future, emphasis is

expected to be given to passive solar applications for multi-family

housing as well. Minimal research is forseen for office or retail buildings. Heating is expected to continue to be the most important energy

research issue for buildings, with little or no research in lighting,

airconditioning or ventilation. International cooperation will continue

to be highly valued with the principal medium being the International

Energy Agency. Direct communication between researchers is of course also valuable and the intent of publishing this report.
N BS»1 14A iwev. 2»«0) 3. Publication Data

July 1983

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See Instructions)

1. PUBLICATION OR

REPORT NO.

NBSIR 83-2724

2. Performing Organ. Report No

4.

TITLE AND SUBTITLE

Swiss Research in Building Heating Conservation

5.

AUTHOR(S)

S. Robert Hastings and R. Ruggli

6.

PERFORMING ORGANIZATION (If joint or other than NBS, see Instructions)

Building Physics Group

national bureau of standards Swiss Federal Laboratories

DEPARTMENT OF COMMERCE for Materials Testing

WASHINGTON, D.C. 20234 CH 8600 DJjbendorf> Switzerland

7. Contract/Grant No. DE-AI101-7 6PR06010

t. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

Passive and Hybrid Solar Energy Division

Office of Solar Heat Technologies

U.S. Department of Energy

Washington.,..DC ?nsfts

Swiss National Energy Research Fund,

NEFF

Basel, Switzerland

10. SUPPLEMENTARY NOTES

| | Document describes a computer program; SF-185, FIPS Software Summary, Is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant Information. If document Includes a significant

bibliography or literature survey, mention It here)

Swiss research on heating energy conservation in buildings is presented to

encourage communication among researchers. A background on Switzerland's

climate, geography, construction industry, and energy situation is included

to provide a context for the subsequent review of a sample of research

projects. Each project is described with a statement of research objectives,

technical approach taken, project status, brief findings, future work planned

or recommended, and resulting publications. The sample of projects is taken

from the subjects of community scale solar concepts, mathematical simulation,

instrumented test cabins, instrumented buildings, and design tools and data

bases. The final section discusses a structure for surveying research projects

in a country in order to examine where efforts are now concentrated and what

subjects are not addressed. Swiss research is examined using this structure

and an assessment is presented.

12.

KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) energy conservation in buildings; European building research; field measurement of

building energy use; passive solar heating; Switzerland; test method development.

13.

AVAILABILITY

Unlimited

| | For Official Distribution. Do Not Release to NTIS

| | Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402.

| ] Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

153

15. Price

$ 16.00

USCOMM-DC 8043-P.80

]I