UNITED STATES PARTMENT OF JMMERCE

IBLICATION NBS TECHNICAL NOTE 789

Technical Options

For Energy Conservation

In Buildings
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards 1 was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology,

the Institute for Computer Sciences and Technology, and the Office for Information Programs. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United

States of a complete and consistent system of physical measurement; coordinates that system

with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of a Center for Radiation Research, an Office of Measurement Services and the following divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Nuclear

Sciences 2 — Applied Radiation 2 — Quantum Electronics a — Electromagnetics 3 — Time

and Frequency 3 — Laboratory Astrophysics 3 — Cryogenics ". THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved methods of measurement, standards, and data on the properties of well-characterized

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distributes standard reference materials. The Institute consists of the Office of Standard Reference Materials and the following divisions: Analytical Chemistry — Polymers — Metallurgy — Inorganic Materials — Reactor

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the use of available technology and to facilitate technological innovation in industry and Government; cooperates with public and private organizations leading to the development of

technological standards (including mandatory safety standards), codes and methods of test; and provides technical advice and services to Government agencies upon request. The Institute consists of a Center for Building Technology and the following divisions and offices: Engineering and Product Standards — Weights and Measures — Invention and Innovation — Product Evaluation Technology — Electronic Technology — Technical Analysis — Measurement Engineering — Structures, Materials, and Life Safety ' — Building Environment * — Technical Evaluation and Application ' — Fire Technology.

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts research and provides technical services designed to aid Government agencies in improving cost effec- tiveness in the conduct of their programs through the selection, acquisition, and effective utilization of automatic data processing equipment; and serves as the principal focus within

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THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination and

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1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted; mailing address Washington, D.C. 20234.

3 Part of the Center for Radiation Research.

3 Located at Boulder, Colorado 80302.

4 Part of the Center for Building Technology.
Hs&reaT Sorest! cT StanjSar^

NOV 7 $3

Technical Options

For Energy Conservation In Buildings

National Conference of States on

Building Codes and Standards

and

National Bureau of Standards

Joint Emergency Workshop on

Energy Conservation in Buildings

» t a

Held at the ^ T&dhnJdQ/ icZe. no. 7 2 I

U.S. Department of Commerce

Washington, D.C.. June 19, 1973

Prepared by

Building Environment Division Center for Building Technology

Institute for Applied Technology

National Bureau of Standards Washington, D.C. 20234

NBS Technical Notes are designed to supplement the Bureau's regular publications program. They provide a means for making available scientific data that are of

transient or limited interest. Technical Notes may be

listed or referred to in the open literature.

***v^ s

"»EAU Of

U.S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director

Issued July 1973
National Bureau of Standards Technical Note 789

Nat. Bur. Stand. (U.S.), Tech. Note 789, 184 pages (July 1973) CODEN: NBTNAE

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (Order by SD Catalog No. C13.46:789). Price $2.35 domestic postpaid or $2.00 G.P.O. Bookstore.
FOREWORD

In late May 19739 the Office of Building Standards and Codes

Services of the Center for Building Technology, National Bureau of

Standards was approached by the National Conference of States on

Building Codes aaa Standards with a request that the Bureau assist

the States in preparing a workshop in energy conservation in buildings,

Specifically, the Bureau was asked to identify measures that State

officials could responsibly recommend to their Governors, many of

whom had initiated conservation actions in anticipation of an energy

crisis they felt to be imminent. The workshop was held on June 19,

1973; the material reproduced in this Technical Note was among the

items distributed at the workshop to State, local and Federal Government officials as well as industry representatives and members of the

press

The staff of the Building Environment Division of CBT was called

upon to prepare this document under the pressure of this urgent deadline. They drew upon the expertise of Bureau staff members, on the

technical literature and on contributions of many colleagues in industry and other agencies of government.

No technical effort undertaken in so short a time can be accomplished without raising some question of technical and economic controversy. This is particularly true in the present case in that scientifically valid answers have yet to be obtained for many of the facets

of energy use and conservation in buildings. For example, the concept

of human comfort is exceedingly difficult to deal with quantitatively.
Therefore, this document should be read by all with this understanding:

the technical options presented herein should be considered as a basis

of reference for considered professional judgment.

For those who need technical guidance now, it is hoped that this

document will be of practical use.

James R. Wright, Director

Center for Building TechnologyInstitute for Applied Technology

National Bureau of Standards

IV
CONTENTS

FOREWORD iii

CONTENTS v INTRODUCTION vi

1. TECHNICAL OPTIONS FOR EXISTING BUILDINGS

Summer Cooling

Opening Statement 1

No Extra Cost 3

Winter Heating

Opening Statement 25

No Extra Cost 27

With Extra Cost 44

2. ENERGY CONSERVATION FEATURES

Insulation 72

Fenestration 79

Lighting 93

Appliances 99

Domestic Hot Water 102

Human Comfort 106

3 TECHNICAL OPTIONS FOR NEW BUILDINGS

Building Design 118

Building System Design 134

4. MECHANISMS FOR IMPLEMENTATION OF ENERGY

CONSERVATION TECHNOLOGY IN BUILDINGS 146

5

.

REFERENCES 172

INTRODUCTION

The purpose of this report is to provide reference material on the

technical options for energy conservation in buildings. It has become

increasingly evident in recent months that available energy reserves may

be inadequate to meet peak energy demands in the United States this summer

and possibly over the next few years. Actions relating to energy conservation are needed which will impinge on two important aspects of this "energy

crisis." These are a near-term shortage of fossil fuels, and the threat of

brown-outs and blackouts resulting from excessive peak demands for electricity„

*1/ Principal uses of energy in the U„ S. are indicated on Figure A„ —

Automobiles account for 68% of the transportation sector or about 17% of

total annual energy consumption. Widely publicized efforts are currently

underway to reduce this level through reduction of the amount of traffic

and maximum speeds of automobiles on the nation's highways. The industrial

sector is the dominant user of fuel energy in the U. S., 41„2% of the total.

Of this, nearly 40% is used for process steam and 28% is used as direct heat,

It is not clear how much energy use could be reduced in this sector. However, if substantial savings in energy use can be achieved in the residential and commercial sector these actions could significantly reduce the

impending shortages.

To determine how much impact energy conservation actions in buildings

could have it is essential to understand patterns of energy use in buildings,

V

Figure B shows the principal uses of energy in buildings. Note the dominant

*Numbers refer to references listed at end of text

vii
role of space heating, which occurs, of course, mostly in the winter

months. Summer loads of residential and commercial buildings consist

primarily of air conditioning -- an estimated 56% of the summer load

for commercial buildings and 30% for homes and apartments. Therefore,

these are the most logical targets for concerted energy saving efforts.

Also, it is important to note the interdependence of these various types

of load. As will be shown in some detail in subsequent sections of this

report, actions in any one of these areas are likely to influence energy

use in others and often beneficially,.

An estimate of the potential energy savings achievable through actions

in the residential and commercial sector is presented on Figure C. These

potential savings are expressed as percentages of U. S. total annual energy

use. For this estimate for existing buildings it is assumed that summer

cooling and winter heating loads could be reduced 307=, and 40%, respectively

In the absence of any other basis for estimating the extent to which such

measures would be adopted and when, it has been assumed that just 107o of

these savings would actually be achieved.

For new buildings a wider range of energy saving options is available.

Again in the absence of data on public and industry response to such measures, it has been assumed for this estimate that just 10% of new buildings

each year would be impacted to this extent.

In summary, it would appear that these potential savings in the

residential and commercial sector may have the same order of magnitude as

potential energy savings in the transportation sector.

The balance of this report presents the details of the technical

options which give rise to these estimates.
Actions pertinent to existing and new buildings are considered

separately. In each of the three major portions of the chapter dealing

with existing buildings -- i„e., summer cooling, winter heating, and

other energy conservation features -- actions which can be accomplished

voluntarily or without expense are considered separately from actions

which require some modest effort or expense on the part of the building

occupant or owner. Throughout this report, emphasis has been placed on

technical options „ Economic implications of such options have not been

detailed.
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Summer Cooling

Existing Buildings

With and Without Extra Cost

Opening Statement

Use of summer cooling systems provides a worthwhile

investment both in dollars and in energy for improvement

in worKing conditions and quality of life which is not

subject to debate because of the current recognition of energy

utilization concern. The need, however, is evident to reduce the

energy consumption to provide summer cooling, by improving

the energy performance of cooling systems, by reducing the loads

imposed on cooling systems, and by conscientiously reassessing

the levels of cooling needs. The total use of energy for cooling

will continue to increase - our objective is to reduce the relative

requirement for each essential cooling system, existing or new,

in order that the service rendered by such systems will

continue to serve people. Even though the energy used for

residential and commercial summer cooling is less than 3 percent

of the national annual total it is 42 percent of the summer total for these types, of buildings, and it does represent an annual national energy expenditure of more than 1.5 x 10 Btu*

1/

(in 1968 and increasing at 10 percent per year) . If it is

assumed that wasteful cooling system practices can be improved

by implementation of the techniques to the extent presented

here, then it is reasonable to expect that the energy requirement can be reduced as much as 30 percent over present rates,

* -, Patterns of Energy Consumption in the United States.
in many cases without sacrificial reduction of needed performance,

In many cases the actual performance of systems can be improved

at the same time that both dollar cost and energy cost is lowered,

Some of the suggestions to be made in our presentation

today can be implemented with little or no cost. Others would

require investment of materials or equipment and labor. Not

all of these modifications have had broad experience because

traditionally buildings have been constructed with primary

concern for first cost, and some of the devices may not have

an early payback in dollars although they can be expected to

accomplish the energy reduction tasks. It is our hope that

the necessary field and laboratory work will be done to

evaluate these suggestions and determine other means to

conserve our valuable energy resources.

Many of the suggestions for reworking existing systems

and designing new systems can best be utilized by considering

the investigation of all elements. This integrated design

can best be done by professional engineers, architects and

designers
Summer Cooling

Existing Buildings

No Extra Cost

o Reduce use of cooling systems

Turn off cooling systems not actually needed for people

or essential processes. Many cooling systems either in total

or in part provide cooling in spaces which do not need cooling.

These could be eliminated with little or no sacrifice . Examples

of these areas are entrances, halls, storerooms and other such

spaces which people use either infrequently or for only short

periods

Turn off cooling systems at all times when spaces are unoccupied. Many spaces are unnecessarily cooled continuously

throughout periods of non-occupancy, for example homes and

apartments unoccupied all day, meeting rooms, auditoriums, etc.

which are used only occasionally. If cooling cannot be turned

off completely during periods of non-occupancy, set thermostats

(and humidistats) at the highest setting on the controls.

Turn off cooling systems in parts of buildings not in

use. To facilitate this many buildings could have the occupancy

schedules arranged to group light load uses in one wing, or on

one floor rather than scattered throughout the entire building.

The energy reduction to be obtained by turning off systems

will, of course, be determined by the extent to which these

steps apply to a particular building. It is estimated that,

on the average, this could reduce energy usage by 5 to 10 percent
o Raise thermostat and humidistat settings

Thermostat settings of 75°F or lower are not uncommon, in

fact, may be prevalent, for summer cooling operation. In

systems with humidity control space humidity of 50% is a customary design. Recent studies show that, with suitable

clothing, temperatures approaching 80°F and humidities approaching

60% R.H. may be acceptable.

Raising thermostat settings to 80°F and humidistat settings

to 60% R.H. could reduce energy demand by an estimated 15% com- pared with operation at 75°F and 50% R.H. (Note: In some re- heat systems internal operating temperatures must also be raised,

along with thermostat settings, to effect the desired energy

savings .

)

Many systems because of poor zoning, poor distribution,

improper location of controls, or improper control function, may

actually operate at temperatures below desired levels

.

Adjusting and balancing such systems will reduce the energy

requirement to the extent that overcooling is eliminated.

Humidity controlling systems, particularly those which use reheat, present opportunity to reduce energy usage by raising the

humidistat to the highest acceptable setting. These systems

operate to control humidity by cooling the air to remove moisture, then reheating as necessary to maintain the desired

room temperature. Most of these systems use "new" energy such

as electricity, steam or hot water for the reheating operation.
Even systems which use "recovered" heat (normally discarded)

will use less energy If the humidistat setting is set at the

highest acceptable level.

o Reduce cooling loads

Turn off or reduce to the lowest acceptable level all

lights and heat-releasing appliances. Lighting, particularly

contributes heavily to the cooling load of offices and

commercial buildings. Encourage use of high - efficiency

lighting at the point of actual work and minimize excessive

general lighting. Reducing internal lighting saves energy in

two ways: (1) reduction of the energy to operate the light,

and (2) reduction of the load on the cooling system because

the light energy is no longer released into the space. In

some of the commercial buildings, lighting loads may be 50%

of the total load. In homes, lights and appliances (TV sets,

fans) increase the cooling load and should be turned off when

not actually needed. Optimize use of natural light.

Minimize use of major heat producing devices or appliances

whenever possible during periods of operation of the cooling

system, or at least during periods of peak load operation of

the cooling system. Peak load power plant operation is

usually much less efficient than normal load application.
Use stove and oven ventilation hoods - the cooling load

of the makeup air required by the hoods will probably be less

than the heat release of the cooking operation. Avoid excessive

cooking during the hottest weather.

To accomodate the higher temperature settings, encourage

use of informal lightweight clothing.

In homes, turn off furnace pilots during the cooling

season when practical. It is recognized that the service

system for turning on pilot lights for winter may be taxed

after the first cold night.

Reduce excessive ventilation. Cut back forced ventilation

to minimum acceptable levels and operate ventilation systems

only when necessary. Minimize infiltration by keeping all

doors and windows closed during operation of the cooling system.

Leave storm doors and windows in place during the cooling

season. Seal off or close all unused chimneys and other

unneeded vents.

Minimize solar loads. Shade all windows exposed to direct

sunlight. Use light colored or reflective shades. Close

Venetian blinds.

Utilize outdoor air for cooling whenever possible. In

homes opening doors and windows and placing fans in selected

locations to draw air through the building can provide interior

comfort when the outdoor air is just a few degrees cooler than

the desired indoor temperature. In apartments, office and

commercial buildings use of outdoor air for successful comfort

6
cooling is more difficult to accomplish because of the lack of

through paths for the air, lack of screens, non-openable

windows, etc. Normal air ducts generally do not move sufficient

air for cooling unless the supply air is at least 15 degrees

below desired indoor temperature.

o Maintain cooling systems and components in clean condition

and in good working order

Keep cooling system components such as coils, blowers,

and especially filters, clean. Maintain entire system in good

condition. It is difficult to quantify the energy cost for

allowing cooling systems to operate in poor mechanical conditions *

It is reasonable to estimate that a general energy reduction

of 10 percent could be realized if a cooling system is kept

clean and in good operating condition compared to operating

that same system with dirty heat transfer surfaces, dirty

filters and improper mechanical conditions
Summer Cooling

Existing Buildings

With Extra Cost

Suggestions in this section are those which can be implemented with investments of money, equipment and labor.

Suggestions in the previous section which required little or no investment should also be considered in support of the

suggestions in this section.

Implementation of some of these procedures can result in

lower overall dollar costs and energy requirements for providing

normal cooling services than many existing systems designed

prior to recognition of the urgent need to conserve energy

and those designed with only first costs in mind. It Is also

possible that implementation of some effective energy-saving

systems may not provide early dollar payback . Detailed longterm or "life-cycle" energy and dollar cost analysis should be

made for all major new or modified cooling systems.
o Reduce the cooling load.

Reduce heat transmission through the building exterior

(1) by adding or installing effective insulation [criteria

for determining adequate insulation effectiveness will be

discussed by others later in this presentation as will other

features relating to basic design.] Many buildings have

inadequate insulation and the various techniques for adding

insulation should be investigated.

(2) by reducing glass area and by installing insulating

glass (or storm) windows and doors. Replace high conductive

window frames with those of lower conduction values

.

(3) by installing exterior solar shading devices, such as awnings, wings, balconies, trees, etc, to shield windows and

walls from direct solar heating. Paint exterior surfaces in

light colors and install light colored roofing.

(4) by insulating and ventilating attics and roof crawl

spaces to reduce top floor cooling load. Hot ceilings on top

floors of buildings not only require more cooling because of the

heat flow downward, they actually require lower air temperatures

to compensate for the radiant heat emanating from the ceiling

surface. In homes, even those with ceiling insulation, thermostat controlled attic ventilating fans will reduce the interior

cooling load sufficiently to more than offset the energy

required for fan operation. Such fans can also be used to

provide cooling by outside air through the house at night if

proper air flow dampers or other devices are installed.

9
Install additional zone controls to permit selective use

of cooling systems in only those areas of a building actually

in use at a given time. Such additional zoning control should

provide means for turning off cooling in unused areas in

addition to providing selected levels of control during

occupancy periods

.

Reduce lighting loads by installing more efficient lighting

fixtures sized to meet task plane needs . Avoid excessive

general lighting by deactivating certain fixtures, or installing

lower wattage elements. Install ventilated or water cooled

light fixtures to remove a major part of the cooling load from

the lights by cooling means other than the space cooling system.

Keep light fixtures clean to avoid need for extra fixtures.

Establish schedules and provide automatic means for

turning off lights, ventilating fans and cooling systems to

match actual demand needs. Scheduling of activities in buildings

to use one wing or one floor during light occupancy can facilitate

establishing an optimum building use pattern.

Install automatic pilots in all heat operated devices

in the conditioned spaces , particularly furnaces , gas clothes

dryers and even stoves in homes

.

Reduce unnecessary ventilation by installing suitable

interior air filtering (odor and particulate) devices to lower

the need for outside air. Ventilation air loads are a major

portion of most cooling systems. If ventilation cannot be

reduced install heat recovery devices (such as thermal wheels,

10
heat pipes, "run-around circuits," etc.) to salvage the cooling

effect in the exhaust air.

Reduce infiltration by repairs to the building such as caulking windows, weatherstripping doors, sealing penetrations

and points, installing revolving doors and automatic door

closures, etc.

o Improve cooling system efficiency

Eliminate reheat systems (for humidity control) which

require "new" heat for the reheat function - convert to heat

recovery systems (commonly referred to as "run-around" or bootstrap systems) which utilize the heat rejected from the

cooling system for reheat

.

Install equipment when needed for replacement or new

uses, which has optimum energy-use characteristics. For example

cooling units can be obtained with a wide range of effectiveness

In selecting new equipment conduct "life-cycle" energy-use

analysis to determine which system will require the least total

energy use. Consider all possible combinations of equipment/

building characteristics, particularly those with heat recovery

features

.

Install short-term (one- or two-days) heat storage

equipment where applicable. For example, some buildings require

cooling during part of a day, and heating part of a day - a

11
heat storage system will permit storing some of the heat

normally rejected during cooling and make it available for

'heating use during the night.

In all buildings which have separate heating/cooling

systems, install control means to assure that simultaneous

operation Is either eliminated or minimized. In many buildings

overlap or duplication of heating/cooling system operation

occurs without being detected. A detailed analysis of the

building systems characteristics will identify the possible

areas for improvement in this regard. In homes, an interlock

which prevents operation of one system when the other is

operating can be installed, if not already provided.

Install heat recovery devices for all elements of the

cooling system where opportunity for essential energy

reduction exists. For example, use rejected heat from electric

generating engines or turbines, waste heat boilers, or incinerators to power heat operated cooling systems . Consider

on-site generation of power to provide this source of energy

for cooling. Burn solid waste as a source of low cost energy.

Consider powering cooling systems by prime movers other than

electric motors when such applications are feasible, such as areas where electric power supply is marginal for the summer

demand. Modify mechanical cooling systems to operate at

condensing temperatures which drop as a function of outdoor

temperature rather than hold a constant pressure.

12
Insulate and seal all ducts in non-conditioned spaces.

In homes, particularly, this accounts for large losses in both

cooling and heating.

In building with central cooling systems consider the use

of separate spot or zone cooling units for spaces which are used for occupancy when the majority of the building Is

unoccupied. For example, in homes with central cooling

installing a small room cooler in the bedroom would permit

turning off the large system during sleeping hours.

Similarly, in commercial buildings those office or other spaces

which operate around the clock can use unit cooling systems

during those periods when the majority of the building is

unoccupied and the main system can be turned off. Some hospitals

have found it practical to furnish individual cooling units

in patient rooms which are used only when and if the occupants

wish to pay for the service.

Central cooling/heating systems in multi-family apartments

and in some multi-occupancy office buildings in which the cost

of providing these services is included in the rent do not offer

the incentive or, in some cases, the physical means to the occupant to minimize the use of the services. The use of individual

metered systems, billed to the occupant, offers the advantage of

allowing the occupant to have heating or cooling as desired and

inherently includes the cost incentive to minimize the use to

actual needs. Installation of such metering should be considered

13
in modification of existing buildings or in designs of new buildings . Modify the building cooling system to use cool outside air

in lieu of the powered cooling system whenever the conditions

permit. Many cooling systems operate at low outdoor temperatures

and could make use of the outdoor air if the system were so designed.

Implement effective maintenance/preventive maintenance

schedules to keep all cooling system components and in

optimum operating conditions. Such scheduled maintenance may

not always represent an optimum cost feature but should assure optimum energy utilization.

14
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24
WINTER HEATING

- Existing Buildings

Opening Statement

Winter heating systems are a necessity for human health

and comfort. The current effort to reduce and conserve energy

for heating does not and should not impact severely on this

basic human need.

The need to reduce energy consumption for heating by eliminating waste of heating energy is evident and can be accomplished

by reassessing our levels of heating needs. The total use of

energy for heating will continue to increase so that our conservation objective is to reduce the relative requirements for

essential heating systems that exist or are newly installed.

Energy used for heating buildings, residential and com- mercial, is about 18 percent of the national energy consumption

15 and represents a expenditure of 10.9 x 10 Btu annually (in

1968 and increasing at 4 percent per year) .— If wasteful heating

practices can be improved as much as anticipated then it is

reasonable to assume that the energy requirement can be reduced

as much as 40 percent over present rates, in many cases without

sacrificing a reduction of needed performance. Further, the

heating system performance may be improved at the same time that

both dollar cost and energy cost is lowered.

25
Some of the suggestions presented here can be implemented

at little or no cost . Others would require application of

materials, equipment and labor. Not all of these suggestions

have been applied on a broad scale because buildings in the

past have been designed and constructed with first cost as the

primary ground rule. Some suggestions have an early payback

and others may take longer but all are expected to save energy.

We hope that necessary data will be gathered in the laboratory

and in the field to evaluate suggestions made here and by others.

Many of the suggestions made for existing buildings could

also apply to new buildings. When considering reworking of

existing heating systems or installation of new systems the

suggestions for both should be investigated. Such an integrated

approach can be done by professional engineers, architects and

designers

26
Winter Heating

Existing Buildings

No Extra Cost

o Set your thermostat lower

If you are now setting your thermostat at 76 or 80°P

consider lowering the setting to 72 or 70 or 68°F and wearing

more clothing. Roughly, for each degree above 70°F it will

cost about 3% more for heating in a typical U. S. climate. This

is true because the heating load is directly dependent upon the

temperature difference between indoors and outdoors. The smaller

you can make that difference the higher the percentage of savings

Obviously, lowering the thermostat for long periods of

time such as week-ends and vacations saves considerable heating

energy

Setting your thermostat lower overnight can save energy

It has been said that this is not worthwhile because the

drop in temperature of the building and its furnishings over- night requires as much or more heating energy in the morning

to restore comfortable conditions as can be saved. If energy

is saved then how far back should the thermostat be set and

for how long? As an example here are some results of an NBS-conducted laboratory test on a fully furnished 4-bedroom townhouse .

27
Figure 1 shows what happened to the temperature in this 60,000

pound insulated wood-frame house when the outdoor temperature

was rapidly decreased to about 34°F and then held constant

with no heating or lighting energy being supplied to the indoors

Note that in 8 hours the indoor temperature decreased from

about 78°F to 69°F and it took about 24 hours to decrease to

58°F. These results are predictable by computer. Other tests,

Figure 2, show that when the thermostat was lowered from about

75°F to 65°F for 8 hours at night a savings of 9% heating

energy per day was observed for a night time temperature of

about 3°F and about 12% for a night temperature of 21°F.

Table 1 is computer calculated and shows the 24-hour percent

fuel savings per day for 25 cities when the thermostat is

lowered 5, 7 1/2 and 10 °F at night for eight hours between

10 pm and 6 am. The table indicates that even though the

percentage of fuel savings is higher in warmer climates the

total savings will be greater in colder regions where more

fuel is used.

In larger buildings energy can be saved by discontinuing

humidity control at the end of the workday. It must be

recognized that energy is required to produce water vapor to

satisfy the humidity demand.

28
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30
Table 1

Percent Fuel Savings* with

Night Thermostat Setback

From 75°F

Setback 8 hours; 10 pm to 6 am City

Atlanta

Boston

Buffalo

Chicago

Cincinnati

Cleveland

Dallas

Denver

Des Moines

Detroit

Kansas City

Los Angeles

Louisville

Milwaukee

Minneapolis

New York City

Omaha

Philadelphia

Pittsburgh

Portland

Salt Lake City

31

5° Setback 7 1/2° Setback 10° Setback

11 13 15

7 9 11

6 8 10

7 9 11

8 10 12

8 10 12

11 13 15

7 9 11

7 9 11

7 9 11

8 10 12

12 14 16

9 11 13

6 8 10

8 10 12

8 10 12

7 9 11

8 10 12

7 9 11

9

7

11

9

13

11
Percent Fuel Savings* with

Night Thermostat Setback

From 75°F (cont'd)

City 5° Setback 7 1/2° Setb ack 10° Setback

San Francisco 10 12 14

St. Louis 8 10 12

Seattle 8 10 12

Washington, D. C. 9 11 13

*Minneapolis-Honeywell Data, 1973.

32
o Close off rooms not used and turn off heat

Closing off rooms and turning off the heat saves energy

simply because the heating system need not supply that room. The amount saved would depend on the room size, weather and

the time. Care should be used in cold climates to drain water

from pipes or other containers that may freeze in the room or alternatively do not close off the room so tightly as to allow

temperatures to go below 32°F.

o On winter days let the sunshine in but pull the shades and

drapes at night

Solar heat can be used to help maintain room temperature.

Any "green house effect" translates into energy savings because

less heat is required from the heating plant.

At night when the window glass is chilled a closed blind

or drapery reduces radiation heat loss from people near the

window and may prevent them from feeling colder and turning

up the thermostat. Closed blinds are usually not fitted

tightly allowing room air to circulate through the space

behind the blind and for this reason only a minor savings of

fuel energy can be realized from blinds and drapes.

33
o Reduce air leakage (drafts) and ventilation

Warm air leaking from a building is replaced by cold air

which must be heated. For many houses about 35% of the heating

energy is used to warm the cold air which enters because of

leakage . Therefore it is important for energy conservation to

close and seal tightly openings from the indoors to the outdoors . Examples of air leakage openings include cracks around

windows and doors, attic stairway doors, fireplace dampers when

not in use, electric light ceiling fixtures, around plumbing

vents or pipes, air ducts penetrating ceilings or walls, etc.

A 1/4 inch crack 3 feet wide under an attic door could cost

$5.00 a winter in energy waste. Simply placing a scrap piece

of carpeting over the crack could stop this leak.

For larger buildings that have power ventilation systems

reducing the amount of ventilation and size of fan motors , and

operating by scheduling operations to use ventilation only where

and when it is actually needed can save a considerable amount of

energy, as much as 50% over inefficient operations. As an example

see Figure 3.

o Be careful about open windows and doors

Open windows and doors represent a huge heating load.

Cold air passing through a building will by-pass the insulating

effect of walls, windows, doors, ceilings and floors causing

the thermostat to start the heating plant which in turn tries

34
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35
to heat a building that is being flushed with cold outdoor air.

A simplified example of this is to open the bedroom window

before retiring and not closing the bedroom door. The cold

outdoor air finds it way to the thermostat while you are sleeping

and the heating plant operates, sometimes fruitlessly, all

night long wasting heating energy. For most situations a common sense approach should prevail. For example, standing

in an open doorway talking with callers for long periods of

time doesnt make energy conservation sense. Keep the

conversation brief, send the caller on his way, or if prudent

invite him in and close the door to keep the heat in. Also,

as mothers know, children need to be constantly reminded to

close the door behind them until it becomes an ingrained habit.

Windows not normally opened should be latched to prevent or reduce constant air leakage through the cracks

In large buildings where there is an almost constant

stream of people entering and leaving the building use of such

techniques as revolving doors, double sets of doors, and

especially engineered heating and air systems can make a substantial impact on energy consumption for the building and

should be encouraged.

36
o Reduce the temperature in public spaces, corridors, hallways,

lobbies, etc.

Public spaces such as lobbies are not occupied by a given

individual for a very long period of time. People usually

move through these spaces, stand and talk for short periods of

time but seldom sit for hours at a time. Reducing the

controlled temperature even a few degress could save considerable

energy in a given large building over a heating season. For employees that must spend their workday in these spaces

selective heating of the actual work space could be provided

and these employees could be encouraged to wear heavier

clothing.

o Institute rigorous schedules for planned operation of

ventilation

Ventilation systems in existing buildings are sometimes

operated continuously and often without conscious planning to

respond to the actual need. Operating ventilation systems

only as needed in response to known building occupancy

schedules could save energy. The ventilation required in modern

buildings is variable with time of day and level of building

occupancy. It is only partially predictable but the important

point here is to first examine present scheduling with a view

for changes that can be made to save energy without seriously

influencing occupant comfort. Most ventilation systems can be adjusted.

37
Generally, the rate of ventilation to satisfy odor

requirements changes in a ratio of 8 or 10 to 1 depending on whether the occupants are heavy smokers or non-smokers . Normal

occupancy in an office building, for example, may occur for

only about 10 hours per day and the use of toilets and

cafeterias, where high levels of exhaust are needed, may be

correspondingly less than 50 percent of this time as indicated

in Figure 4 . Some heating and ventilating systems are designed

or can be operated for a high rate of ventilation with outdoor

air during mild weather to control indoor conditions and a much lower level during the heating and cooling seasons

A prominent mechanical engineering consultant from Chicago

has estimated that 30 to 50% of the energy required for heating

and 15 to 20% of the energy required for electrically powered

air conditioning could be saved by variable exhaust of air and

by utilizing heat recovery devices between exhaust and intake

air. The design parameters are shown in Figure 5.

o Wear heavier clothing

Six key variables have been identified as having a major

influence on human comfort in occupied building spaces. These

are the temperature, relative humidity, air velocity, mean

radiant temperature, the degree of physical activity and the

amount of clothing worn. The occupant has a great deal of
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40
control over his own physical activity and clothing. Generally,

bare arms and ankles tend to make a person feel cooler in heated

spaces and simple compensation by wearing long sleeves, coats,

sweaters and heavier and longer socks permit lowered room

temperatures thus saving energy.

o Maintain an efficient heating plant

The operating efficiency of a heating plant is a very

important factor in influencing the amount of fuel energy used

for heating. For example, two prime sources of energy waste

are the amount of air supplied for combustion and the conditions

of the furnace or boiler. Heat transfer surfaces should be

clean to minimize any reduction of heat transfer that may be

caused from soot that results from products of combustion.

The quantity of air received by the burner influences the

efficiency of combustion. Too much air increases heat losses

to the chimney and too little air does not allow complete

combustion. Heating contractors or utility company personnel

can check and adjust your furnace. Other things can be done

effectively by building personnel. For example, air filters

should be cleaned or changed and electric motors, pumps or other

devices should be oiled or lubricated. A potential energy

savings of 10% or more can be realized by maintaining the heating

plant in good operating condition.

41
o Turn off - turn down lights and electric appliances except

when needed

It is true that heat released from lighting fixtures and

appliances in the winter contribute to maintaining indoor

temperatures. The suggestion to turn off lights and appliances

unless actually needed Is made in the context of energy

conservation. The rationale is that the thermal efficiency

of electric energy supplied from the power plant is of the

order of 30-35 % and savings of electric energy at the point

of consumption contribute directly and considerable to savings

of fuel energy at the power plant. It has become customary to

perform janitorial services in commercial and office buildings

after the majority of the occupants leave in the evening.

For operational and security reasons the lighting systems of

these buildings remain on into the night while the work is

being done. Frequently entire buildings remain lighted even

though the work at a given moment is limited to one area. Using lighting only in areas of work and scheduling all work

in one area at a time would permit significant reductions in

the lighting energy. Consideration should be given to scheduling

during daytime hours those janitorial tasks which will cause minimal interruption or interference to normal activity. This

suggestion applies to all types of buildings year around.

42
o Concentrate evening work or meetings In a single heating zone

In large buildings instead of heating the whole building

to accomodate a few people who must work in the evening

consider asking the people to move for the evening to a heated

zone In the building and then reduce the heating on the

remainder of the building to save energy.

43
Winter Heating

Existing Buildings

With Extra Cost

o Add a clock thermostat

Night-time thermostat set-back can be done manually but

in practice because of the necessity of actually turning it

back it may not be done consistently. Automatic clock

controlled devices to accomplish night set - back of the

thermostat are available. Also, many buildings are presently

equipped with clock-type thermostats that are not being used.

o Add insulation

The addition of thermal insulation to save energy has been

verified many times. In existing housing, for example, adding

insulation to the attic floor, about 6 inches deep, will

contribute to comfort in both winter and summer and will

pay for itself from savings from heating and cooling bills . Adding insulation to side-walls should be done with technical

advice because of the possibility of moisture condensation

within the walls

.

Adding insulation to large existing buildings that are

not insulated or contain minimum amounts of insulation may

present practical and expensive difficulties because of such variables

as the ratio of glass to insulated area, access to add insulation, interruption of personnel or vital services, and other

considerations. Usually masonry buildings are difficult to

44
retrofit with insulation. Therefore, professional advice should

be sought before undertaking massive modifications because insulation is only one element which should be taken in context with

other energy conservation techniques in large buildings

The potential for energy conservation by using thermal

insulation is large for all types of new buildings.

o Add insulating glass or storm windows and doors

Storm doors and windows and insulating glass save energy

because they cut in half the heat that would be lost through

the glass area of single pane windows. Generally, considering

air leakage and conduction of heat through walls the net effect

of heating bills could be a reduction of 10-15 percent.

Further benefits in terms of comfort and a reduction of cold

floor drafts are inherent. Also, storm windows and doors are effective in reducing heat gain in summer and thereby reducing the

load on air conditioning equipment.

o Caulk and seal around windows and doors, and other openings

Caulking, sealing, and use of weatherstrip is very effective

in sealing out the entry of cold air into a building and the

exit of warm air from the building. Because of the necessity

45
to heat cold air leakage about one-third of the output of the

furnace is used for this purpose and any reduction air leakage

will save energy.

o Insulate heating ducts and seal against air leakage into

non-heated spaces (attics, crawl spaces)

Ducts that convey warm air from the furnace to the

occupied spaces sometimes pass through unheated spaces such

as attics and crawl spaces that are cold. Within these areas

the ducts should be heavily insulated and sealed against leaking warm air to the cold space through cracks in the ductwork.

When the furnace blower is working the duct work is operating

under positive pressure. The air lost from these sections is

a direct waste of energy

In some buildings piping containing fluids such as water

or steam will pass through cold spaces . These should also be

heavily insulated to prevent gross heat energy loss.

o Maintain heating equipment - clean heat transfer surfaces,

change filters, set flames and combustion air

This subject was mentioned under the heading of no cost

suggestions. It is estimated that ten percent energy savings

can be realized when comparing a well maintained heating system

with a system that is not in good operating condition.

46
It is suggested that this work be done by service professionals .

o Install heat recovery and conservation devices

In buildings, especially large buildings, two prime

areas of heating system loss are stack losses and ventilation

air losses . Recovery of some of the heat that normally would go up

the stack and channeling it back into the heating system

represents a means to conserve energy. Also, when warm air is

exhausted from a building by a mechanical ventilation system and

at the same time cool air is drawn in as fresh air, energy can be saved by removing heat from the exhausted air and using it

to warm the cool air which otherwise must be heated by the

normal heating system. Several techniques are available

for accomplishing this energy savings. For example, to recover

heat from stacks heat pipes, runaround circuts, automatic stack

dampers, etc. and for ventilation systems runaround circuts, thermal

wheels, heat pipes, heat pumps and other heat exchange circuts.

The potential for ventilation heat load reduction is illustrated

in Figure 6.

47
o Install automatic pilots

Energy can be saved if pilot lights on heating devices are replaced by substituting an automatic ignition device to light

the burner. Gas pilot lights usually operate continuously 24

hours a day and typically consume 1 to 2 cubic feet of gas per

hour. The fuel energy savings could amount to the pilot con- sumption when the burner is not operating. Replacing pilots

could in some cases allow corrosion in furnaces or boilers and

each system should be evaluated before extensive changes are made

o Adjust ventilation systems

It may be possible to adjust ventilation systems in a

way to cut down on the amount of air flow and maintain

comfort conditions . Use of heat recovery devices and additions

of odor removal filters could be studied as a means for maintaining comfort with less net energy consumption.

o Avoid use of portable electric heaters by improving main

heating system

Electric energy could be conserved, with its attendent

savings in fuel energy for power generation, if the use of

portable electric heaters is avoided by improving the main

heating system of the building.

48
Fuel fired heating plants in a building operate at thermal

efficiencies of about 60-75 percent while the thermal efficiency

of electric power generation is about 30 percent. The difference

in efficiencies is indicative of the amount of energy saved.

o Replace defective or inefficient heating systems with systems

of higher efficiency

Over the years improvements in heating systems have been

made to make them more efficient. If present systems are defective and are known to be inefficient the difference in

efficiency between an old and new system is a savings in fuel

energy when both systems must accomodate the same load.

o Modify systems for zone control using systems of higher efficiency

In some larger buildings the heating requirements of

different zones or areas in the building vary but the original

heating system is designed to respond to a single control or thermostat. Those types of systems could be modified by the

addition of control valves and the addition of thermostats that

prevent overheating with its attendant waste of energy.

49
o Provide means to transfer heat from the core of a large

building to the cool periphery needing heat

Heat generated by people and activities in the central

core area of large buildings is often in excess of what is

needed to provide heating needs. If this excess heat is

ventilated to the outdoors or is absorbed by refrigeration

systems at a time heat is supplied to the colder periphery changes

could be considered to transfer this heat to where it is needed

and when it is needed by modifying existing systems or their

controls. The energy savings would amount to the equivalent

of that energy that would have been rejected to the outdoors.

o Install automatic door closers

Open doors represent a major heat leak. People tend to

leave doors open even in winter. Automatic door closers would

save the energy that would normally be lost. The savings are difficult to quantify but it is estimated that it is worthwhile.

Some data are available in the handbooks of the American Society

of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

New York, N. Y.

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71
ENERGY CONSERVATION FEATURES

INSULATION

Of all energy conservation methods for building heat losses

and gains, none can be considered as important as thermal

insulation. President Nixon recognized this in his energy

messages (June 1971 and February 1972) by directing HUD-FHA

to upgrade insulation standards for single and multi-family

dwellings

As an example of the impact possible in residences, NBS

in 1970 prepared a 25-year projection of energy and cost

savings from thermally improved buildings . Figure 6 shows

the projected national stock of residential units for 25 years

from about 60 million to 100 million units. The annual energy

consumption for heating and cooling these residences is projected

in figure 7 on the assumptions that a building would not be

thermally improved and present (1970) insulation levels

would prevail and on the assumption that insulation levels

would be improved to the extent of 10 percent for existing

buildings and 50 percent for new buildings . Annual and

accumulated savings are shown as energy requirements in Q units

15 (1Q unit =10 Btu) . The accumulated savings show 50 Q units

over 20 years. Figure 8 shows the fuel cost in billions of

dollars of the accumulated energy savings to be about $100

billion over 25 years assuming energy prices remain at 1970

levels . Figure 9 shows the effect if prices of energy should

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increase annually at rates of 2, 4, 6, 8, and 10 percent,

e.g., at 1% about $200 billion over 20 years. These projections

for housing are also indicitive of the scope of similar energy

and cost savings potential that might be attained in other

types of building such as office buildings.

It is possible to reduce the heat loss or gain in residences

by 50 percent through the use of thermal insulation in the

ceilings, (6 inches) walls (3 inches) and floors (3 inches).

As an example , Figure 10 was prepared to illustrate the

application of four insulation requirements in terms of a heat load factor defined as Btu/(1000 ft of heated volume)

2 (degree-day) for a hypothetical residence of 1200ft .

In addition to conserving energy, increased insulation can

save on heating furnaces (about 20 percent smaller), cooling

machinery (about 10-15 percent smaller), and also smaller

flues, smaller electrical wire sizes to equipment and smaller

duct sizes .

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78
ENERGY CONSERVATION FEATURES

FENESTRATION

General building design practice over the past decade

has called for large expanses of glass with most commercial

building having between 50 and 60 percent of the exterior

surface area occupied by these transparent surfaces . Historically it was for the purpose of making proper use of

natural light; however, most often today it is to provide a view of the outside, which in most instances is to cater to a real or assumed psychological need.

In contrast to the favorable characteristics of windows,

they can have a significant impact on the heating and cooling

loads imposed on the building. For example, figure 11

depicts a typical process occuring during the summer with

solar radiation impinging on a 1/4" clear plate window and

also energy being conducted across it as a result of hot outdoor

3/

air. - As can been seen over 80 percent of the incident solar

energy enters the space and the total energy entering is

probably ten times larger than through a comparable amount

of conventional wall. In the winter time, a different kind

of problem exists. The ability to conduct heat of ordinary

plate glass is five to ten times more than typical well insulated

walls. Consequently they become a source of "heat leaks" in

cold weather, being only partly compensated for by the solar

energy. In addition, their high conductance results in a cool

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interior surface which is detrimental to thermal comfort and

can cause condensation problems under certain circumstances.

It is possible to enjoy the benefits of windows and yet

compensate for their negative characteristics through proper

design initially as well as proper use.

1. S hading : It is possible to reduce solar transmission

through windows significantly by proper use of shading. The

most effective way is by use of external shading devices.

These can be in the form of trees, shrubs, overhangs, awnings,

building fins or eyebrow reveals. Figure 12 is a schematic

representation of how overhangs and side fins are placed to

shade windows. Figure 13 shows one way in which the building

design and shading devices can be integrated together.

The American Society of Heating, Refrigerating and AirConditioning Engineers (ASHRAE) specify in their 1972 Handbook of

1/

Fundamentals, the percent reduction of solar heat gain that can

be expected for a single plate glass window as a result of

internal shading devices as follows

Venetian Blinds Roller Shade

Opaque Translucent

Medium Light Dark White Light

3&% k5% 41$ 15% 61%

81
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Figure 13

83
Similar results are given by ASHRAE for closed draperies showing

that they can reduce solar gain by as much as 65%. These internal

shading devices are relatively inexpensive and yet can be very

effective. Of course they must be used properly, that is,

shades and drapes should be closed during the cooling season

on sunlit surfaces and yet opened when needed during the

heating season.

2 . Use of other than ordinary glass : Where the opportunities arise in the design of commercial buildings, consideration can be given to the use of other than single plate

glass. Most glass manufacturers have available a wide variety

of glasses that are more efficient from a thermal standpoint

and yet allow visual communication with the outside.

As an example of comparison with figure 11, figure 14 depicts

what happens under the same environmental conditions where a commercially available double glass is used having one pane

3/ coated.— The use of such glass is no doubt more expensive

but might be justified as is demonstrated by the following

example

Consider the design of the Toledo Edison Building by the firm

of Samborn, Steketee, Otis, and Evans. The Architects, along

with Libby-Owens Ford, did a detailed computer study of the

effects of a variety of glasses on the buildings' construction

and operating costs. They selected a chromium coated dual wall

insulating glass that made an added expense initially of

$122,000 compared with the conventional 1/4" plate glass.

84
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However, offsetting this initial expense was a savings of

$123,000 in initial costs for the heating and cooling equipment,

ductwork and the like. (A 64.7 percent reduction in the

capacity of the central refrigeration system, a 53.2 percent

reduction in the capacity of the central heating equipment and

a 67.9 percent reduction in the capacity of the distribution

system) . The pay-off is the fact that the design chosen

results in an energy consumption savings of 729.4 kilowatts

per hour (translates to a savings in yearly operating cost of

approximately $40,000).

The architect today has a wide choice of transparent surfaces

to install. Heat absorbing glass hit the market in the late

50 ' s and early 60's and can absorb as much as 45 percent of

the solar energy striking it. Combining it with external

shading such as sunscreen can be very effective, blocking

up to 75 percent of the available solar energy. The effect

of air movement between the screen and window offers further

reductions. The big change in glass, however, has come in the

past three or four years with the advent of reflective metallic

coatings. They can block any desired amount of solar light

and heat, with the standard transmittance ratings being 8,

14, and 26 percent; combined with dual insulating glass, the

result is glass that keeps heat where it is wanted -- outside

or inside — depending on the weather conditions.

The individual homeowner would generally not consider the

kind of glass mentioned above but indeed might be interested

86
in double pane or storm windows. They offer a reduction in

solar transmission for the cooling season of 10 to 15 percent

(excluding the use of internal shading devices) but more importantly the glass area becomes at least twice as resistant

to normal conduction transmission losses in the winter time.

These losses can be significant as shown in figure 15 for a typical one story concrete slab house located in the center of

the United States.-'

It should be noted that the window framing itself is important from a thermal standpoint. In a recent study by the

Hittman Associates of Columbia, Maryland on the energy consumption of typical residences in the Baltimore-Washington area ,- they found that aluminum windows lose approximately 2 5 percent

of the total window loss through the frame assembly. In contrast, wood assemblies lose only approximately 13 percent of

the total window loss. The accompanying two figures, 16 and 17,

show a comparison of total loss (winter) and gain (summer) for

the two kinds of window frames.

3 . Use of smaller amounts of glass

It appears feasible that in both commercial and residential

dwellings it is possible to reverse the trend of large expanses

of glass to minimize their poor thermal efficiency and yet allow

for a sufficient amount of visual communication.

In a recent study completed at NBS on a federal government

building in Manchester, New Hampshire (this will be described

more fully in a later section) , the effect of amount of glass

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on yearly energy requirements was determined. Reducing the

window to exterior wall ratio (based on floor to ceiling height)

from 50% to 10% resulted in a savings of yearly energy demand

for all services by over 10%. Perhaps the ratio of 10% is too

small; however, the architect should strive for a pleasing

design giving proper fenestration due consideration.

Consideration should definitely be given to effective

amounts of glass in residences. In making recommendations

to FHA for inclusion into their Minimum Property Standards,

NBS in 1972 devised figure 18 for determining allowable

percentages of glass for any Individual room. Under winter

design conditions with the indoor air temperature at 75°F, the

glass area of a living room/unit expressed as a percentage of

its total exterior wall area should not exceed the value along

the ordinate of the figure. The abscissca is the ratio of the

floor area of the room/unit to the total exterior wall area including glass areas and doors and the third parameter "X" is

as shown, the U value of the glass times the temperature

difference at winter design conditions . This rationally

derived chart thus accounts for the geographic location as well

as the kind of glass used i.e., larger amounts of glass could

be used for a given location provided one went from single pane

to storm windows or insulating glass.

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92
ENERGY CONSERVATION FEATURES

LIGHTING

In office buildings, lighting consists of from 25 to 60

percent of the cooling load of air conditioning equipment and

contributes from 20 to 30 percent of the total annual demand

for electrical energy. Clearly, the reduction in lighting or the better utilization of energy expended for lighting will

have a pronounced effect on not only the power demands for

lighting, but also the power demands for operating air conditioning equipment. Without altering life styles or increasing

total costs, energy required to light new buildings could be

reasonably reduced by 25 percent. Demand for lighting could

be cut by at least 15 percent in most existing buildings.

Suggestions for the reduction in or better utilization of

7/

energy expended for lighting is summarized as follows: -

1. Turn off lights when not needed . When the working or living space is empty, secure and not used for display or observation there is no need for lighting. The power energy

savings realized are direct in winter and could be one and

one half times the energy output of the lighting fixtures

that have been turned off in summer due to the additional

savings in cooling.

2

Control window brightness and utilize daylighting as practicable . The levels of illumination required for working

and living spaces can be made adequate by the control of window

93
brightness and proper utilization of daylighting. Control

systems could be utilized to turn off or reduce the amount of

electric lighting when daylighting provides adequate illumination.

3

.

Provide planned operation and maintenance procedures . Operation and maintenance of lighting (electric and daylight)

should be considered for both the utilization of power and

economic considerations. Maintenance involves keeping lighting

equipment clean and in good working condition so that

illumination levels remain adequate for prolonged periods of

time .

4

.

Use lighter colors on surface finishes of ceilings, walls , floor and furnishings . Light finishes increase the utilization

of available light. By repainting ceilings, walls and floors

and using lighter colors of furniture, the average illumination

level of the room using the same light sources could be increased

by as much as 30 footcandles (amount of light received by a surface). Reflectances of the surfaces should be in the following

range*

Ceiling finishes 80-90$

Walls 40-60%

Furniture 26-44$

Office machines and equipment 26-44$

Floors 21-39$

American Standard Practice for Office Lighting, ANSI A132 . 1—1966

.

94
The upper reflectance limits have been selected to avoid ex- cessively bright surfaces which could be uncomfortable.

5. Use efficient light sources and luminaires . For overall

design, consideration should be given to the use of the more

efficient light sources such as fluorescent and high pressure

sodium and metal halide (HID) lamps . Incandescent lamps are about 30 percent as efficient in terms of the light output per

electric power used (lumens/watt) as fluorescent lamps.

Incandescent Lamps

40-watt general service lamps produce 11 lumens/watt

60-watt general service lamps produce 14.3 lumens/watt

100-watt general service lamps produce 17.4 lumens/watt

100-watt extended service lamps produce 14.8 lumens/watt

1000-watt general service produces 22 lumens/watt

As can be seen higher wattage incandescent lamps are more efficient than lower wattage ones and in the same

way general service lamps are more efficient than extended

service (longer life) lamps.

Fluorescent Lamps

2 24-inch cool white lamps produce 50 lumens/watt

2 48-inch cool white lamps produce 67 lumens/watt

2 96-inch cool white lamps produce 73 lumens/watt

HID Lamps

400-watt phosphor coated mercury lamps produce 46 lumens/watt

400-watt metal halide lamps produce 74 lumens/watt

400-watt high pressure sodium lamps produce 100 lumens/watt

95
1000-watt metal halide produce 85 lumens/watt

Again higher wattage lamps are more efficient. HID lamps are

usually used outdoors. More efficient luminaires produce a greater amount of light on the task surface with less wattage,

as shown in figure 19. Where direct or semi-direct incandescent

luminaires may require a load of 5.5 watts per square foot of

floor area to produce a 50 foot candle level, general diffuse

fluorescent luminaires require only 2.2 watts per square foot

(*IES Lighting Handbook)

.

6 . Design lighting for expected activities . Where task

positions are fixed and known, the lighting should be designed

accordingly where less lighting should be provided in surrounding non-working areas. The Illuminating Engineering Society

recommends in the IES Lighting Handbook , values of illumination

for visual tasks on a group of tasks in an area. The following

statement is made: "Supplementary luminaires may be used in com- bination with general lighting to achieve these (task) levels.

The general lighting should not be less than 2 footcandles and

should contribute at least one-tenth the total illumination."

Task oriented lighting by supplementary luminaires or suitable

means can reduce electrical demand in many existing buildings

as much as 20 to 50 percent

.

Corridor and room lighting should be reduced to the

maximum extent consistant with safety and security. The above

mentioned reductions in light level can be accomplished by

turning off lights or substituting lamps of lower wattage.

96
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7

Design with effective luminaires and fenestration . Luminaire and fenestration lighting effectiveness depends

on how well the light provided enhances the visibility of visual

tasks. Light from either source, if not controlled can reduce

visibility by producing veiling reflections and glare.

8. Use heat transfer luminaires . By using luminaires with air

and water heat transfer capabilities, heat from luminaires can

be removed before entering an occupied space in warm weather or conversely the heat can be utilized in occupied spaces in cold

weather. By this means 30 to 80 percent of the total heat output

of the lights can be withdrawn.
ENERGY CONSERVATION FEATURES

APPLIANCES

The several electrical appliances currently being used

within a modern home consume approximately 12,000 KW-hr of

electricity per year. The probabilistic distribution of annual

energy consumption within a residence for appliances as given

£/

by Hittman Associates are shown below:

Appliances Annual KW-hr

Central Air Conditioning 3600

Lights 2000

Range 1175

Refrigerator-Freezer 1830

Clothes Dryer 993

Color TV 500

Furnace Fan 394

Dishwasher 363

Clothes Washer 103

Iron 144

Coffee Maker 10 6 Miscellaneous 1200

12408

Other appliances are listed as miscellaneous. These values

are exclusive of the energy consumption of the heating system

and the domestic hot water heater. It is obvious that the

decreased use of any one of the above appliances will give

99
reductions in energy consumption. Suggestions for reducing

energy consumption are given as follows:

1. Cooking equipment could be made considerably more efficient

in the following ways

:

a) Use cooking pots for better surface burner contact

by using a pot of the same size as the burner and a

flat bottom pot

.

b) Improve oven insulation in new appliances.

c) Reduce heat transmission and air leakage of oven doors.

d) Provide an outdoor vent for the oven for summer use.

e) Use lids on pots and pans.

f) Use thermostatically controlled stove surface units to

reduce energy usage.

g) When possible, use the oven in place of surface stove

units and cook several items at once

2. Refrigerator-Freezer

a) Frostless units consume approximately 1 2/3 times the

energy of manual defrost units . Use manual defrost units

where practical.

b) Door gaskets on refrigerators and freezers should be

checked for air leakage. If you can easily slide a dollar bill past the gasket it leaks air.

c) Clean condenser coils of units to provide more efficient

operation

d) Open doors of units only when necessary to reduce

heat and moisture gains

.

100
3. Clothes washer-dryer

a) Use maximum size loads for washer to reduce frequency

of use

b

)

Use cold and warm water settings with appropriate

detergents to reduce hot water demands

c) clean lint filters for more efficient operation

d) Vent the dryer to the outside particularly for summer conditions

e) Use automatic drying cycle because overdrying wastes

energy

4. Other Appliances

a) Discourage use of instant-on television sets. Without

picture tube on, these sets continuously consume

energy, e.g. about 50 watts for black and white

and 100 watts for color.

b) Load dishwasher completely to reduce frequency of

operation

c) Use heat producing appliances when demands on the

cooling system are less - early mornings, evenings

and cool days

.

101
ENERGY CONSERVATION FEATURES

DOMESTIC HOT WATER

Ways to Reduce Energy Consumed in Domestic Hot Water Heating

At the present time the energy used for domestic hot water

heating constitutes 4% of the total annual energy consumption -

2.9% for residential and 1.1$ for commercial .—This is equivalent

to 1/4 of the energy used for residential space heating and about

1/6 of the energy used for commercial space heating. Suggestions

for reducing energy consumption for hot water heating are given

below

:

1. Reduce Hot Water Temperature to 120°F

Most domestic hot water systems presently maintain water

temperatures of l40-150°F or more. Average hot water utilization temperatures are in the range of 105-H5°F with the

exception of dishwashing and laundry operations- (l40°F for

residential and 180°F for commercial and institutional) . Since

some dishwashers have built-in booster heaters and there are detergents available for use at low water temperatures, it

is not necessary to maintain hot water at l40-150°F. The

savings by maintaining water at a temperature of 120°F are:

a. Reduction heat losses from storage tanks and piping

by 20-45$. Since the heat loss Is about 1/4 of the

energy input to a water heater, this amounts to 6-12$

reduction in energy usage. For systems with long

circulating pipe-lines (high-rise and large buildings),

the reduction will be greater.

102
b. Reduction of energy input to hot water used for laundry

and other residential uses (30% of the overall daily

hot water usage) where no mixing with cold water is

required. A 12-15% reduction in daily energy con- sumption for water heating is possible.

2

Reduce waste of hot water in taking showers and baths . The typical daily hot water usage for bathing is about

42% of the total daily usage of hot water in a residence. If

this amount can be reduced by 1/3, an energy savings of 1-45? in

daily hot water heating is possible. The percentage saving will

be higher for motels, hotels, dormitories and high schools since

the major hot water usage is for washing.

3

Operate dishwashers and clothes washers only at full

loads to reduce the number of washings needed .

4Operate dishwasher and clothes washer in the morning or at . night to reduce peak period power demand on electricity .

5

Shut-off the circulating line pump during non-occupancy

period : Most large office and commercial buildings have a well defined occupied period and a long hot water circulating

pipe-line. Shutting off the circulating pump at night and

during weekends, holidays, will eliminate pump power and the

103
heat loss from the long run of pipe-line. (The line loss for

insulated pipe is about 30 Btu/hr-ft, and for un-insulated

pipe is 60 Btu/hr-ft of pipe) .

6

.

Use detergents designed for cold or warm water washing : This will eliminate the need for high water temperature

laundry operation.

7

.

Insulate hot water storage tank if presently not insulated

to reduce heat loss .

8

.

Insulate long run of circulating line - A bare pipe losses

twice the heat from a pipe with 1/2" of insulation .

9

.

Repare leaky faucets . One drop per second of hot water from a leaky faucet will

amount to about 650 gallons of wasted hot water and energy

over a year.

10. Check hot water temperature control device . Replace if

not regulating properly.

11. Replace shower heads with smaller ones to reduce flow rate,

104
12 . For new buildings, avoid over-capacity In sizing hot water

system . Locate storage tanks as close to point of usage as possible to avoid long run of pipe-line. Consider the installation of separate water heaters or booster heaters for special

purpose high temperature operation.

105
ENERGY CONSERVATION FEATURES

HUMAN COMFORT

In various other parts of this document, reference has been

made to saving energy by the use of more clothing, less clothing,

higher or lower levels of temperature and/or relative humidity.

Justification for these changes can be made on the basis of

research done over the past fifty years.

There are approximately twenty prominent indices or groups

of experimental data that have been presented to indicate man's

response or feeling when subjected to a certain environment.

The majority are experimental in nature (i.e., human subjects

have been exposed to a specified and controlled environment

and asked to describe their feeling or at least have physiological measurements taken on them during the exposure)

.

However, during the last several years there has been a great

deal of interest in describing mathematically the thermal

interaction between man and his environment, thus enabling

one to predict what occurs or how one might feel in given

surroundings

.

Undoubtedly the most familiar of all comfort indices is

the American Society of Heating, Refrigerating and Air Conditioning (ASHRAE) Effective Temperature. The scale was first

established in the 1920' s by Houghten and Yaglou.— Subjects

wearing clothing having an unspecified insulation value were passed between test chambers in which the temperature, air

velocity, and humidity were maintained at specified levels

and were asked to describe their feeling immediately upon

106
entering the new environment. The results are shown in'

figure 20 where lines of constant thermal sensation are shown

plotted on a temperature-relative humidity chart . The experiments were conducted for a large range of air velocities;

however, the data shown here is for an air velocity of less

than 20 fpm. The lines of constant thermal sensation were arbitrarily given numerical values corresponding to the

temperature at which the line intersected the 100% relative

humidity curve. One should note the large dependence of thermal

sensation on relative humidity. This dependence continues to

be accepted as valid in the very hot region but has been

abandoned as inaccurate in the comfort region or the region of

most interest in analysis for energy conservation.

Perhaps the most definitive experimental study on thermal

comfort is one conducted on over 1600 college students at

9/ Kansas State University over the past several years .— The

students were exposed (over a 3 hour period) to a uniformly

heated or cooled environment (wall temperatures identical to

the air temperature) with moderate air velocities and asked

to vote on a scale from 1 to 7 which ranged from cold to hot

1. cold

2cool

3. slightly cool

4. comfortable

5. slightly warm

6

warm

7. hot

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All subjects, males and females alike, were clothed in

cotton twill shirts and trousers (shirts worn outside of the

trousers), and cotton sweat socks without shoes. The net

insulating value for the clothing ensemble, as computed by means of an electrically heated copper manikin has been

determined to be 0.6 clo* which has been generally accepted

as the standard clothing for thermal comfort studies

Even though the results are available for men and women

separately and also for the votes taken at each half an hour

for the entire 3 hours of exposure, the data shown in Figure

21 is an average for the votes of men and women taken together

at the end of the 3 hours. One should note the very slight

dependence of comfort on relative humidity. Studies such as these have led to the conclusion that temperature is far more important than relative humidity at comfort conditions.

One of the most significant attempts to predict analytically

the thermal interaction between man and his environment is

presented by P. 0. Fanger of the Technical University of

10/ Denmark in his recent book Thermal Comfort -— He begins by

pointing out the most important variables which influence the

condition of thermal comfort:

1. activity level (heat production in the body)

2. thermal resistance of the clothing (clo-value)

*1 clo represents a measured resistance to heat transfer of

the clothing ensemble of 0.1b sq. m hr °C/Kcal. (0.88 sq

ft hr °F/Btu or equivalent of an overall heat transfer

coefficient - 1.13 Btu per (hr)(sq. ft)(F)).

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3. air temperature (dry-bulb)

4

mean radiant temperature

5. relative air velocity

6. water vapor pressure in ambient air

The basis of his analysis is the so-called general comfort

equation which defines all combinations of the variables which

will create thermal comfort . The importance of such equations

lies in the fact that once proven valid, they can be used

very quickly to determine the effect of changing any one of

the six variables, something considerably more difficult by

experimentation. His comfort equation was modified to define

a variable predicted mean vote (PMV) and a scale similar to

the one used in the Kansas State Studies was chosen:

-3 cold

-2 cool

-1 slightly cool

neutral

+1 slightly warm

+2 warm

+ 3 hot

The numerical values, however, are lower by 4 . A scale is thus

obtained which is easier to remember, as it is symmetrical

around the zero point, so that a positive value corresponds to

the warm_ side and a negative value to the cold side of neutral.

In figure 22 the results are compared with the experimentally

determined KSU comfort vote. As can be seen the agreement is

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excellent for the comfort line ( KSU = 0, PMV = 4) but not so good for environmental conditions outside of the comfort range.

As mentioned previously, an advantage of an analytical

model such as this is the capability of observing the effect

of one of the six controllable parameters without having to

conduct extensive experiments. For example, it may be unrealistic to assume that during the summer subjects will wear the

standard 0.6 clo clothing ensemble. Certainly in hot weather

people would be more inclined to wear lighter clothing such as shorts and an open neck shirt with short sleeves. Data for this

type of clothing ensemble (clo = 0.25) is compared with the

standard Kansas State clothing ensemble in figure 23. The

comparison shows what one might intuitively expect , For

lighter clothing, subjects would report comfort at 4 or 5°F

warmer temperature. It would be expected that they would

vote cool at a somewhat higher temperature also (approximately

6°F) . However, both subjects would vote hot at approximately

the same temperature and relative humidity.

Consequently for the sake of energy conservation, one

can justify higher temperature limits in the summer if lighter

clothing is worn and lower temperature limits in the winter if more than the standard amount of clothing is worn. Figure 24

has been included here to show precisely by use of Fanger's

analysis, how the "acceptable room temperature" can be

varied by changing the clothing.

113
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115
In setting upper and lower limits for the control of

temperature and/or relative humidity for the sake of saving

energy, the ASHRAE Standard 5 5-66 can be referenced. This

standard was established in 1966 and based on a careful analysis

of all existing analytical and experimental studies on human

thermal comfort. Its contents are presently being reevaluated

in light of the massive amount of work that has been done over

the last several years

The Standard is very specific in its stipulation of thermal

comfort conditions . It states in part that in a region between

3 inches above the floor and 72 inches above the floor and

x at

least 2 feet from any wall, the following should be met at

all times

1. The dry bulb temperature shall be between 73 and 77°F.

2. The relative humidity shall not exceed 60 percent

and be greater than 20 percent.

3. The air motion shall not exceed 45 fpm and be greater

than 10 fpm.

Of course most space conditions are not completely uniform

and are also time dependent. To cover these more realistic

occurrences, the Standard also includes the following:

4. The rate of change of dry bulb temperature at any

point in the occupied zone shall not exceed 4 deg/hr

if the peak-to-peak variation in the temperature cycle

is two degrees or greater within the limits stated

in 1.

116
5. The rate of change of relative humidity at any point

in the occupied zone shall not exceed 20 percent/hr

if the peak-to-peak variation of the humidity cycle

is 10 percent or more, within the limits stated in 2.

6. When the mean radiant temperature* in the occupied

zone differs from the dry bulb temperature, the dry

bulb temperature shall be reduced 1.4°F for each 1.0°P

mean radiant temperature elevation above air temperature

and vice versa.

7. The rate of change of mean radiant temperature at any

point in the occupied zone shall not exceed 3 deg/hr

if the peak-to-peak variation of the MRT cycle is

1.5°F or more, within the limits stated in 6.

Consequently based on the Standard, one could justify

77°F and 60$ RH in the summer and 73°F and 20$ RH in the winter.

It is felt by proper clothing the upper temperature limit can be extended to 80°F and the lower one can drop to 68°F.

*Mean radiant temperature is defined as the uniform surface

temperature of an imaginary black enclosure with which man

(also assumed a black body) exchanges the same heat by

radiation as in the actual environment.

117
NEW BUILDINGS

The opportunity for energy savings in new buildings falls

into one of the following categories:

1. Building structure and/or fabric design

2. Building system design, and

3. Building operation.

The areas unique to new buildings by and large fall mainly

into the first two categories. Consequently those will be

discussed here since many of the operation controls have been

mentioned previously.

Building Design : Since there presently exists few controls or regulations

on the use of energy in buildings, many of the steps that can

and should be taken to conserve energy have to be economically

effective to be accepted on a wide scale. It is therefore

imperative to have life cycle costing as an integral part of the

decision making process and design process for new buildings.

That is , decisions on design and selection of equipment should

be based on the lowest initial cost plus owning and operating

costs (including energy costs) for a reasonable life expectancy

of the building rather than lowest first cost alone. The impact

of this statement can be demonstrated by use of the following

example

:

Consider how the increased first cost associated with extra

insulation can be justified on the basis of savings in operating

costs

.

U8
Source : NAHB Insulation Manual 1971. *

Small house, one-story, in Columbus, Ohio. ~ Floor area 1370 ft2 ; total wall area 1480 ft ; Window plus door area 260 ft ^ ; double glass windows

Ceiling

Wall

Heating Cost/yr

Cooling Cost/yr

Operating Cost Savings

Cost of added insulation

Reduction in first cost:

Furnace

Flue

Elec. System

Ducts

Inside wall ducts

Air conditioner

Net first cost

R-7**

R-7**

R-ll**

R-ll**

R-19**

R-ll**

$87

37

$72

33

$66

30

$19 $28/yr

$85 $181

$10 $30

5 10

5 8

5 5

10 10

75 200

$110 $263

$-25 $-82

In any detailed analysis of a building design, one can make the following general statements:

1. For residences, the most significant features include

the use of insulation, control of infiltration, and

to some degree consideration for proper fenestration.

*The calculations were performed by NBS based on data presented in this reference.

**Indicates the level of thermal resistance or degree of insula- tion. The larger the R value, the more the resistance or amount of insulation.

119
2. For commercial buildings, the most significant

features that should be addressed include the use

of insulation, proper fenestration, control of

ventilation amounts, levels of illumination, orientation of the building, and to some degree, the

amount of exposed surface area. Since the importance of all the factors mentioned above has

been discussed in some detail previously, they will not be further

discussed; however the type of analysis generally necessary for

the design of a building for the sake of conservation will be

illustrated here by way of an example.

NBS is participating in a study of the design and construction of a federal office building to be built in Manchester, New

Hampshire. The study was done in order to determine what

could be done in the design of the building to ultimately

conserve energy. The study will be outlined here giving

numerical results and it can be assumed that the results are typical of what one would expect for the analysis of most

commercial buildings of a comparable size.

The building is to be seven or eight stories high having

2 a gross office floor area of approximately 125,000 ft . 11/

A sophisticated mathematical-model for the thermal response

of buildings was used in conjunction with New England weather

data for the year 1962 to determine the thermal requirements

of a building constructed according to "typical design practice"

for that area. The defined building parameters were as follows:

120
1. U-value of the roof - 0.20 ^^

hr ft °F

2. U-value of the walls = 0.30 — E hr ft

2 °F

3 . U-value of the floor R

, above the garage = 0.25 —

hr ft

2 °F

4. Windows - single pane with no external shading but

internal shading so that the solar transmission would be reduced by 50%.

5. Windows area equal to 50% of the exposed floor toceiling height on each floor.

6. The length to width ratio was 2:1 with the long axis

running north to south.

Additional assumptions were made including

1. natural infiltration of outdoor air continuously at

a rate of 1/4 volume of the building per hour

2. Indoor conditions of

Summer Winter

75°F, 50? RH - day 70°F, 30? RH - day

85°F - night 60°F - night

3. For 10 hours a day (Monday thru Friday)

2 indoor lighting of 2.9 watts per ft of gross floor

area occupancy of 600 people,

121
ventilation air introduced from the outside at a rate

of 15,000 cubic feet minute, and

heat output of office equipment at a rate of 1/2 watt

2 per ft of gross floor area.

To determine the effect that possible design changes had on total building energy consumption and not just on heating and

cooling loads, additional assumptions were made that included

1. assumed seasonal efficiency for heating of 60%,

2. assumed seasonal coefficient of performance for cooling

of 2.5, and

3. various other "rules of thumb" for electrical requirements of fans, pumps, cooling tower, elevators, etc.

Once this "basic building" was defined, its yearly energy

consumption was predicted for the year 1962 as shown in figure

25. One should note the relatively large percentage of the

total energy consumed that goes for lighting as well as driving

the pumps and fans for the heating and cooling systems. Figure

26 shows the percentage of the heating load that can be

attributed to the various building components with figure 27

showing a similar plot for the cooling load. Note that over 70 percent of the cooling load during the months of

December and January can be assigned to the lights; however

the load is low during these months.

Following this initial determination, individual design

changes were made and the calculation repeated to determine

122
PROJECTIONS FOR FEDERAL OFFICE BUILDING

5r- Manchester, New Hampshire

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the percent reduction In annual energy consumption. The

results are as follows :

1. Roof U-value from 0.20 to 0.06 3.5%

2. Wall U-value from 0.30 to 0.06 8.5%

3. Floor U-value from 0.25 to 0.06 6.0$

4. Window from single pane to triple pane 13-5$

5. Window internal shading removed * 2.5$

6. Window area from 50$ of exposed wall

area to 10% 10 .5%

7. Building height increased 4 stories** 2.5$

8. Building changed to a square shape** 2.0$

Since these reductions in energy consumption could not be

assumed to be directly additive, one final calculation was made using the following conditions

1all U-values =0.06

2. double pane windows with internal shading

3. window area only 10$ of exposed floor to ceiling height

4original height and shape

The result of this calculation was a 33 percent reduction in

yearly energy requirements compared to the initial building.

One should be cautioned that a constant and optimistic

efficiency was assumed for the heating and cooling equipment

throughout this study. Depending upon the type of system and

*The incre ased cooling load was negated by the reduction in

in heating load during winter months

**These changes were made in such a way that the gross floor area remained the same.

126
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degree of control installed, the 33 percent figure could be

altered significantly.

In order to show what could be done in the sizing of

equipment allowing for realistic fluctuation of space conditions

an exterior zone on the top floor and west side of the building

was isolated for analysis. A completely cloudless summer day

was chosen and a conventional design calculation was done as shown in figure 28. In order to maintain the indoor temperature

precisely at 75°F and constant, a peak capacity of 25,000 Btu/hr

is needed and the accumulated load is 317,000 Btu for the day.

Figure 29 shows that by setting the temperature up 5°F at

night, the accumulated load decreases approximately 8 percent;

however the peak capacity had to be increased by 20% as a result of the need to bring the temperature back down suddenly

at the start of the occupied hours. The result of flushing

the zone out with cool outdoor air at night is indicated in

figure 20. The result was a decrease in the peak capacity back

to within 12% of the value of figure 28 but in addition, the

accumulated load has now dropped further so that it is 2 4%

below the initial value.

Figure 31 depicts what happens if one goes an additional

step and limits the peak capacity to 18,000 Btu/hr in the

zone. The zone indoor temperature stays within reasonable

limits and the accumulated load has been decreased a total of

32%. Figure 32 shows that if the 18,000 Btu/hr unit is limited

further to operation only during the occupied hours , the indoor

128

:
temperature exceeds the acceptable limits. Figure 33 shows the

disastrous effect of applying no cooling.

In conclusion one can say that considerable energy

savings can be effected by proper consideration for insulation

and fenestration during the design phase. Additional savings

are possible by use of outdoor air for natural cooling,

relaxation of rigid temperature limits, and proper sizing of

equipment

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NEW BUILDINGS

Building System Design :

Conduct air side system simulation analysis by using a computer

Computer simulation techniques are available and should

be used for estimating the annual energy consumption of the

several available air side systems. This is particularly

important for those that can utilize heat conservation equipment. The usual air side systems are dual duct, variable

volume and terminal reheat systems. Depending upon the

particular system, the energy consumption is very much

affected as shown below.

Relative Effect of Air-side System on Energy

Consumption*

Systems hconomizer

Relative Annual

Cooling Energy

ln%

Dual Duct no

yes

100

40

Variable

Volume

no

yes

78

37

Constant Volume no 77

*An office building in San Francisco. Analysis by R. F

Meriwether and Associates, San Antonio, Texas.

135
Use heat conservation systems

There exists several heat conservation systems such as

1) Heat recovery system: This system recovers as much as

80% of heat from exhaust air and puts it back into the outdoor

makeup air through the use of rotary heat exchanger (thermal

wheel) , heat pump, heat pipe, or fluid circulation runs around

coils .

2) Heat of light system: Heat from lighting fixtures is

absorbed by air or liquid to be used for space heating or for

terminal reheat in an air conditioning system.

3) Heat rejected from the compressor of the air conditioning

system can be reclaimed for terminal reheat or perimeter heating, through a loop type heat pump or through double-bundle

condenser systems.

4) Wherever electric space heating is employed, heat pump

systems should be considered over straight electric resistance

heating. Package heat pumps are well perfected at present and consume 1/2 to 1/3 times the electrical energy required by

resistance type heaters in many parts of the United States

during a large part of heating season. Even more attractive

is gas engine driven heat pumps where the engine waste heat

is recovered and can be used for space or hot water heating.

The gas engine driven heat pump system with engine heat

recovery can deliver approximately 40% more heat to a building

than the electrically driven heap pump.

5) Heat storage systems to store off-peak output of heating

136
and cooling units for later peak hour usage, if carefully

designed and operated, can not only reduce the peak heating/

cooling hour load, but also reduce energy consumption. A

12/

recent study on a storage type off-peak cooling system showed

50% reduction in peak power demand and 6% reduction in cooling

energy consumption. Similar figures can be expected for heating operations.

Central system vs. unitary system

For a larger building a central system usually uses 10

to 15% less energy than small decentralized package systems,

if properly controlled. In addition, It is easier for the

larger central systems to incorporate energy conservation

devices. These may be impractical for the smaller package

systems

Avoid the selection of oversized equipment

Oversized equipment usually operates less efficiently

than properly sized equipment operating at full load capacity

Modular systems should be considered whereby several small

units could operate continuously at their peak capacity in

place of one large unit operating at part-load most of the

time

Select (when prudent) equipment of high energy rating over

that of low first cost

137
When issuing specifications for procuring heating and

air conditioning systems and components, a prime consideration

usually is the initial cost. However, the specification could

be revised to include a requirement for an energy analysis to assure that the system and its components use minimum energy

for equal performance. This would in effect encourage manufacturers to develop equipment of higher energy rating.

Ventilation system considerations

When safety permits, reduction in ventilating air from a conventional 10-20 cubic feet per minute (CFM) per person to

4-5 CFM per person in the building or occupied space can result in substantial energy saving. (Fan horsepower can consume as much as 45% of the total building electric energy

in some buildings.) In some cases, reducing ventilating air

by 50% can reduce the power consumption by 12.5$. The ventilation air can also be reduced by designing the air supply

system in such a manner that only the occupied spaces in a given building for the occupied time be supplied with air of

the correct amount instead of ventilating the entire building

continuously at a constant rate.

Natural cooling

Buildings can be so designed to take advantage of nature's

ability to cool. Heat dissipation from a building can be

accomplished by night time cooling when the outdoor air is at

138
its lowest temperature. In addition, the sky is a good

absorber of radiant heat and its cooling effectiveness can be

made equivalent to 2 tons of air conditioning if the roof of

a regular home was made to radiate its internal heat to the

sky. In many parts of the United States, the outdoor humidity

is low enough to make the evaporative cooling very effective

during a hot summer day.

Electronic ignition for gas fired furnace

Conventional pilots of gas furnaces burn 223 billion

13/ cubic feet of gas per year in 30 million gas heated houses.

The substitution of the pilots by modern electric ignition

devices can not only reduce gas consumption but also minimize

the cooling requirements during hot summer days.

Use multiple fuel capability

If possible and feasible, consider coal or trash as alternate fuel for gas or oil for the generation of steam

and hot water. Coal is still in plentiful supply in the

United States

.

Night time set-back and start-up cycle

When thermostat set-back for the unoccupied period is

used, it is also necessary to consider a suitable "start-up"

system so that the occupants will be comfortable at the

beginning of the working hour. Unless carefully designed,

139
the start-up requires a large sudden amount of heating or cooling and thus a waste of energy. The start-up time depends

upon the type of building and the outdoor temperature. It is

estimated that heating fuel savings during start-up of more than 50% are possible by the use of well designed "startup" controls.

Temperature control

It is not unusual to be in a room which is either overcooled or overheated. Equally frequent is the situation where

a room is heated during the summer and cooled during the

winter. These conditions could result from improper design

or malfunction of the central system and of course result in

an unacceptable amount of energy waste. It is expected that

energy expenditure could be reduced by a factor of two or more simply by avoiding a system which requires simultaneous

heating and cooling of buildings to attain a desired temperature level

.

Humidity control

In some commercial and institutional buildings, heating

and cooling systems are designed to provide approximately

40-50% relative humidity throughout the year. It is not

necessary to maintain this narrow band of relative humidity.

According to the comfort standard publication by the American

Society for Heating, Refrigerating and Air Conditioning

140
Engineers, the room relative humidity can vary from 20% to

60% when temperature is maintained between 73°F to 78°F. A

desire to maintain the relative humidity at 40% during a typical dry winter day where the outdoor temperature is 10°F

requires approximately twice as much heat for generating water

vapor to maintain 40% RH than to maintain 20% RH . On the

other hand, to maintain 50% relative humidity indoors during

a typical humid summer day (90°F and 50% relative humidity

outdoors) could require 30% more energy from the air conditioning system than that needed to maintain 60% RH . Furthermore,

the intent to control the humidity level at 40-50% throughout

the year often destroys the advantage expected of some of the

heat conservation systems such as those that use outdoor air

to reduce the air conditioning load of office spaces (economizer cycles )

Solar energy utilization

A preliminary study of solar heated houses in selected

areas of the United States showed that a saving of approximately 40% of the normal heating energy consumption is

2 possible by use of a flat plate collector of 560 ft in area

and with 150,000 Btu of storage for an average dwelling in

14/ the Washington, D.C. area. —

In many parts of the United States it may be possible to

assist summer air conditioning by using absorption cooling

which is operated by solar heat . It is essential that the

141
components of the solar energy utilization system, such as collectors and storage tanks, be carefully integrated into the

building design. Solar energy utilization appears to have

good future potential

.

Utilize waste heat

Thermal wheel type or heat pipe type heat exchangers can recover up to 80% of the heat otherwise wasted. Up to 25% in

fuel savings is said to be realized by installing recuperative

combustion systems in burner exhaust

.

Total energy systems

Properly designed on-site electric power generation

systems with the use of engine waste heat recovery for either

space heating or hot water heating and summer cooling could

achieve energy savings of 28 to 40% when compared to conventional systems that purchase the power from the utilities.

Approximately 500 total energy systems are in operation in the

United States. These could provide engineering data and

operating experiences to improve future design of this type

of energy conserving system.

Recycle waste as fuel

Where practical, use normally discarded waste or building

trash as a fuel supplement . The heating value of trash is

approximately 1/4 that of coal. Although in conventional

142
buildings the savings in energy by the use of waste as fuel

is small, for some commercial and industrial operations such

as producing drain oil and sawdust, waste recycling could be

significant

Scheduling for off-peak period

Consideration should be given to the rescheduling of

working hours to off-peak periods, e.g., start air conditioning system one or two hours earlier than normal and pull the

temperature down a few degrees below normal. By doing this

and then resetting the chiller thermostat higher than normal,

the power demand during the peak load will be less. This may

not result in an appreciable reduction of the daily energy

consumption.

If feasible, a substantial energy savings can be realized

by shutting down the chiller one hour before the normal end of

the working day. If the chilled water pump and the air con- ditioning fans are allowed to continue operation, generally no objectionable increase in space temperature is noted.

Electrical system considerations

Wherever practical and found more economical, convert

to higher voltage systems . Use of electrical demand limitors

and power factor correcting condensers should be considered

through a careful engineering analysis for each project to

see if substantial energy saving and/or peak power shaving is

possible . 143
Cut back lighting loads

Building illumination systems can be so designed to take

care of situations where all perimeter lighting can be turned

off and natural lighting used. In certain areas, every other

light could be turned off without seriously impairing visual

effectiveness. Since heat from the lighting fixture constitutes as much as 50% of space cooling load, rational design

of illumination to cut down the lighting power input from

2 2 conventional 4-5 watt/ft to 2 watt/ft would yield considerable reduction in cooling energy consumption. In addition,

it is wasteful to leave the lights on during the unoccupied

periods. Time clock controls should be employed at selected

locations to turn off the unnecessary lights. The table below

shows the effect of lighting design upon the annual heating

and cooling energy consumption calculated for a San Francisco

office building by R. F. Meriwether and Associates of San

Antonio, Texas.

Relative Effect of Lighting and Operating

Hours on Energy Consumption*

2 Operation Watt/ft Heating Cooling

Continuous 4.5 100 100

5 1/2 days/week 2.9 39 74

*Variable volume/economizer cycle

144
In some buildings the lighting for parking lots, building

lighting and security flood-lighting could take as much as

30$ of total building electric load (see below). Use of

photocell switches to minimize the wasteful use of exterior

lighting can be effective

Energy Use by Sources for a Large Commercial

Complex in Houston

MKWH Percent

Chillers 30,123 12

Mechanical room accessories 9,301 4 Fans 25,451 10

Illumination and

Equipment 109,713 44

Parking Lot 73,4l6 30

Total 248,004 100

145
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146
MECHANISMS FOR IMPLEMENTATION OF ENERGY CONSERVATION

TECHNOLOGY IN BUILDINGS

by

Paul R. Achenbach

INTRODUCTION :

Speakers on the morning program of the Joint NCSBCS-NBS Workshop on

Energy Conservation in Buildings described a variety of technical options

for saving energy under three topics; viz.

1. Practices that can be carried out by owners or operators without

cost

2. Practices that can be implemented with modest expenditure for

readily available materials

3. Design opportunities for energy conservation in new buildings.

Obviously, the practices described under the first topic can be regarded as economically sound because they require no expenditure of money,

but only a change in living habits or methods of equipment use. Enough

experience and analysis are available on some of the practices described

in topics two and three to demonstrate cost-effectiveness. For example,

the use of significant amounts of thermal insulation in buildings will

save enough in operating costs to amortize the first cost in only a few

years. Likewise, storm windows are usually a good investment and the

reduction of air leakage by caulking and weatherstripping is cost effective. However, the energy savings that can obtained with a considerable

number of the suggested operating or design concepts have not been

14 7
well documented, nor has the tradeoff between first cost and lowered

operating cost been reliably determined. Laboratory and field studies

are being planned or are in progress to develop the technical and economic data on many of these practices.

PREREQUISITES TO IMPLEMENTATION :

While the needed technical and economic data are being developed it

is appropriate to consider the methods available for implementing energy

conservation technology in the huge inventory of existing buildings and

in the new buildings that are designed and constructed each year. Basic

to the success of implementation is the belief on the part of many

people that there is a potential for energy conservation in buildings at

a price that many are willing to pay. This workshop is evidence that

many State building officials believe that this concept is worthy of

investigation and development. However, all of the segments of the U.S.

population identified in Table 1 have a significant role in attaining

energy conservation in buildings, and the level of their acceptance of

the potential for energy conservation will determine the rate at which

it can take place and the amount of energy savings that will be realized.

Table 1. PREREQUISITES TO IMPLEMENTATION

Acceptance of Energy Conservation Potential

Public

Design Professions

Manufacturers

Builders

Financial Institutions

Regulatory Bodies

148
IMPLEMENTATION PROCEDURES :

A variety of procedures are available for introducing energy conservation technology into the design, construction, and operation of buildings

These can conveniently be grouped in three broad classes; viz., educational, financial, and regulatory, as shown in Table 2.

Table 2. MECHANISMS FOR IMPLEMENTATION

A. Educational

1. Information media — publication, radio, T.V.

2. Industry persuasion through advertising

3. Adoption of guidelines by design professions, owners

B. Financial

1. Energy price structure

2. Mortgage practices

3. Tax, rent, interest subsidies

C. Regulatory

1. Standards, specifications, codes

2. Government directives

3. Energy rationing

The educational procedures are the most democratic type and they require

a broad spectrum of voluntary action and response to have a significant

effect on the nation's energy use pattern. The financial incentives

in the second category require legislation as a means of implementation,

in most cases. The available regulatory procedures range from voluntary

standards and specifications to directives and emergency actions taken at

various governmental levels. The latter type of action would typically

occur only when threats to the health, safety, or national security were

involved.

14 9
A few examples of the various types of action that have been taken

or proposed will be cited to illustrate their characteristics and limitations. Probably all of the newspapers and news and technical magazines

have printed one or more articles in the last year on the energy shortage.

Many public service programs have been shown on television. Every week,

one or more seminars and symposia are held on this subject. The "7 Ways"

and "11 Ways" consumer bulletins issued by the National Bureau of Standards

in collaboration with the Office of Consumer Affairs and the Owens Corning

energy exhibit prepared and widely displayed about two years ago were

educational in purpose.

Various companies have used their advertising programs to provide

worthwhile information to consumers on energy conservation and at the

same time promoting the use of the products they manufacture. Three

examples illustrate the process:

1. Minneapolis -Honeywell, Inc. has published a bulletin showing

how much energy can be saved by the homeowner for three levels

of night setback of their thermostat for 25 cities in the U.S.

2. The Electric Energy Association distributes a bulletin identified

as Sav-a-watt which describes ways to use electric energy more

efficiently.

3. Owens-Corning Fiberglas Corporation distributes on request a

packet of material describing various methods for saving energy

in building operations

.

These efforts have the advantage of providing substantial amounts of

money and organized procedures for distributing useful information to large numbers of people.

15
A few industry associations, professional societies, and some utilities

have voluntarily developed or are developing design practices or product

information related to energy conservation. For example:

1) The Illuminating Engineering Society has published material describing how lighting may be done more efficiently to save

electrical energy.

2) The Association of Home Appliance Manufacturers publish an energy

efficiency ratio for all window air conditioners on the market;

and they have been active for a year or more in developing simulated use tests for refrigerators and other electrical appliances

that could be used as a basis for nameplate ratings on use efficiency.

3) The American Telephone and Telegraph Co. has issued a contract for

a pilot retrofitting of one of their telephone exchange buildings

in New York City to explore the cost-effectiveness of various

building and equipment modifications. The results of this study

will be used to identify modifications to be made on all of their

exchange facilities.

There has been only limited exercise of financial incentives to bring

about energy conservation in buildings, but a variety of procedures are

now under study and several bills have been introduced into Congress involving such incentives. The relation of supply and demand in the energy

market has already brought about significant rises in the price of electricity and all of the fossil fuels. This trend will undoubtedly continue

and it will inhibit to some degree the discretionary use of all these

151
energy sources. Some have suggested that the typical sliding price

scale of electrical energy, oil, and gas for which larger demands by a

given customer can be obtained at progressive lower unit costs should

be reversed to discourage heavy users of energy. However, the legality

of this approach has been questioned because the prices charged for

energy by public utilities must be demonstrably related to the cost of

production.

Proposals have been made that energy and fuel be deliberately subjected

to increased taxes to discourage use, but this approach would tend to

place more burden on the poor than on those of higher income status. The

reverse of this proposal would be to provide tax incentives or interest

rate incentives to assist those who wanted to borrow money for building

modifications that would conserve energy. Such proposals have been suggested in the report of the Ad Hoc Committee on Energy Efficiency in Large

Buildings to the Interdepartmental Fuel and Energy Committee of the State

of New York.

In the regulatory area of standards, specifications, and codes, the

best known documents containing energy conservation provisions are the

FHA Minimum Property Standards. These standards for One- and Two-Family

Houses and for Multifamily Dwellings were recently revised to contain

more stringent requirements on energy use, in response to a Presidential

directive. The FHA Standards are not mandatory on the building industry

unless the builder or mortgage backer wants to take advantage of the

mortgage insurance programs of the Federal Housing Administration.

152
Thus the FHA procedures are a combination of technical standards and

financial incentives through mortgage insurance. The California legislature has just made the FHA requirements on energy conservation mandatory for housing beginning January 1, 1974.

Other developments that could lead to standards or specifications

in energy conservation are the following:

1) The Association of Home Appliance Manufacturers will probably

incorporate typical use tests as a basis for energy ratings in their

equipment standards.

2) The Federal GSA will make broader use of the energy efficiency

ratio in their purchase specifications for air conditioners, and will

incorporate cost-effective conservation practices into their guide

specifications

.

3) Research programs on energy conservation by ASHRAE, AIA, AAI, IES,

NAHB, NSF, GSA, and NBS could lead to standards development by industry,

professional, and standards bodies over a period of a few years.

Government directives and energy rationing are executive actions likely

to be reserved to alleviate short-term emergencies in supply or distribution that threaten the health, welfare, and security of groups of citizens.

One of the principal purposes of this workshop is to explore various

methods or procedures that might be used by the States to limit the use

of energy in buildings in an equitable and uniform manner so as to reduce

the anticipated disparity between supply and demand and still maintain a

153
satisfactory quality of life. Very few documents have been written that

attempt to set forth criteria for limiting energy use in buildings. However, many city, state, and federal groups have been considering how this

might be done, and a variety of approaches have been considered. Some

of these are listed in Table 3.

Table 3. CRITERIA FOR LIMITING ENERGY USE TN BUILDINGS

1. Building dimensions only

2. Building dimensions and climate

3. Number of occupants

4. Thermal properties of building elements

5. Equipment performance

The problem is complex because the criteria must apply to both the building envelope and the energy systems used in buildings; they must account

for climatic variations, various occupancies, and building size; and they

must allow flexibility in design and choice of materials. In addition to

these technical requirements, any satisfactory set of criteria must be

susceptible to effective administration and compatible with other performance objectives for buildings. Table 4 lists some of the more important administrative requirements of satisfactory criteria.

Table 4. CHARACTERISTICS OF A SATISFACTORY CRITERION

1. Understandable

2. Usable by Design Professionals

3. Compliance readily checked

4. Broadly applicable

5. Supports economic design

6. Compatible with other performance objectives

Table 5 lists a set of tests for adequacy and fairness of a set of

energy criteria in relation to the variables in actual building construction. It is possible that a single set of criteria cannot cover all of

154
the variables in Table 5.

Table 5. TESTS OF ADEQUACY AND FAIRNESS

1. Adequate for heating and cooling seasons

2. Adaptable to climatic zones

3. Suitable for residential and commercial buildings

4. Accounts for tradeoffs between space heating and cooling

and electrical usage

5. Control both heat transmission and air leakage

6. Applicable to both building and equipment design

7. Promote cost-effectiveness

EXISTING CRITERIA FOR LIMITING ENERGY USE:

In order to describe the present state of the art in the development

of criteria for energy conservation and to assist in the further discussion of implementation in this workshop, the requirements contained in

four existing documents are summarized in Tables 6 to 8. These documents

are:

1) FHA Minimum Property Standards for One and Two Family Dwellings

2) FHA Minimum Property Standards for Multifamily Dwellings

3) HUD Guide Criteria

4) Report of the Ad Hoc Committee on Energy Efficiency in Large

Buildings to the Interdepartmental Fuel and Energy Committee of

the State of New York.

These documents will be used to discuss the desirable features of a set

of criteria for limiting energy use in buildings.

First, it should be noted that the FHA and HUD documents deal principally with the thermal properties of the building envelope; they place

few limitations on lighting levels; the ventilation limits are rather

155
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15 7
Table 8. REPORT OF

AD HOC COMMITTEE ON ENERGY EFFICIENCY IN LARGE BUILDINGS

TO THE

INTERDEPARTMENTAL FUEL AND ENERGY COMMITTEE

OF THE STATE OF NEW YORK

SUBJECTS COVERED :

BUILDING CONFIGURATION

SYSTEMS FOR ELECTRIC HEATING

COOLING SYSTEMS

VENTILATING SYSTEMS

LIGHTING

INSULATION

ENTRANCES AND LOBBIES

BUILDING MATERIALS

HEAT RECOVERY

COST/BENEFIT ANALYSIS

15 8
liberal; and they reference existing industry standards for most of the

mechanical systems. Since industry standards at the present time contain

few provisions related to energy conservation, the FHA and HUD documents

provide a minimum of change from past practice in the design and application of mechanical equipment.

The FHA-MPS for one- and two-family dwellings contains limits on

the overall unit heat loss and gains of a house (excluding floors) and

the overall unit heat loss of the walls, windows, and exterior doors

taken separately in relation to floor area. These provisions have the

following advantages and disadvantages:

a) Major design flexibility in selecting materials and fenestration

to satisfy an overall requirement.

b) Equal winter heat loss rates in all climatic zones. This feature

might not provide the best tradeoff between first cost and

operating cost.

c) The requirements as drafted allow a relatively high infiltration

loss (25 to 357» in the winter time).

d) All materials combinations have to meet the same criteria.

The FHA-MPS for mult i- family dwellings limits the heating and cooling

requirements by limiting the heat transmission factors of the various

building elements. The specified heat transmission factors vary with

severity of the summer and winter climate and the values are higher for

masonry buildings than for frame buildings. No limitation is placed on

the amount of single glazing, but in colder climates the ratio of double

159
glazing to single glazing is increased with the number of winter degreedays in several steps. There is no direct limitation on air leakage, but

weatherstripping is required on all doors and windows and air leakage

tests are required for windows.

The HUD Guide Criteria provides summer and winter limits on the

heat transmission levels of all building subelements. The allowable

heat transmission values are related to design indoor-outdoor temperature

difference and are constant for all climates. This concept allows the

U-factors to vary inversely with the design temperature difference and

results in approximately equal energy use in all latitudes. The Guide

Criteria provides a limitation on the ratio of glass area to exterior wall

area that varies with building size, climate, and heat transmission factor

of the fenestration. It also provides limits on the air leakage of walls,

windows and doors and an overall limit on the structure.

The recommendations contained in the design section of the report of

the Ad Hoc Committee on Energy Efficiency in Large Buildings to the executive branch of the State of New York cover ten major subjects including

the design parameters of the building enclosure; the heating, cooling,

ventilating, and lighting systems; insulation and building materials; heat

recovery; and cost/benefit analysis, as shown in Table 8. (Other sections

of the report cover the construction and operation aspects of the building

process.) These recommendations are presented in three time frames; short

range (0-2 years), medium range (2-5 years), and long range (more than

5 years). The recommendations were presented in March 1973 and are still

under consideration at the state level.

160
The report of the Ad Hoc Committee is more comprehensive in its

coverage of building equipment than either the FHA-MPS or the HUD Guide

Criteria, but most of the guidelines are expressed in performance-type

language and do not provide explicit criteria for acceptability. Specific

requirements are stated for design summer and winter design weather

conditions, for the level of system overload to be used in design, and

for the overall goal in reduction of energy requirements for large

buildings. The report recognizes the need for more detailed criteria

in certain areas, for computer analysis of loads, for research to develop

the potential for energy conservation of various design concepts, and for

a thorough cost/benefit analysis system and a data bank on economic performance. This report constitutes a broad framework within which more

specific criteria could be developed.

FUTURE CRITERIA DEVELOPMENT :

It is evident from this brief review of existing published documents of a standards or specification nature that no single set of requirements is sufficiently comprehensive to cover the perceived needs

of the States in energy conservation. It is suggested that the

National Conference of States for Building Codes and Standards and the

energy coordinators for the states consider carefully two different

approaches to the further development of criteria for limiting energy use

in buildings.

The first of these utilizes the American National Standards Institute's

consensus standard approach. Professional societies such as AIA and

161
ASHRAE and governmental organizations such as NCSBCS and NBS could serve

as sponsors in the generation of a proposed national consensus standard

using the Sectional committee concept or a modification thereof. This

standard should cover both the building itself and all of the energy-using

systems found in selected classes of buildings (perhaps limited to residential and commercial). After promulgation of the standard as a National

Standard through the American National Standards Institute, it would be

available for adoption by reference by the States with or without modification. The B9 National Standard of ANSI Mechanical Refrigeration Safety

Code is a good model for this procedure. The principal hazards seen

in this approach are the possibility that consensus would not be attained

among the large number of diverse interests and the possibility that the

voluntary standard, when promulgated, could be modified in so many ways

by different states in the adoption process that it would lose its benefit

of uniformity.

The second procedure that might be successful would be patterned

after the FHA Minimum Property Standards process. In this process a

governmental body with authority to implement a standard would use the

resources of industry, the professions, and government agencies to

generate a draft standard under its direction. When a draft had been

produced it would be circulated to all appropriate industry and government

bodies for comment and suggestions. The sponsoring agency would incorporate acceptable suggestions into the standard and issue it for use. Its

use could be voluntary unless its application were combined with tax,

interest, or mortgage payment incentive programs. The potential

162
disadvantages in this procedure are (a) lack of commitment and acceptance

for a standard produced under government leadership, and (b) non-acceptance by the segments of the building industry not requiring subsidies.

The FHA Minimum Property Standards are models of this process.

Other major hurdles to be negotiated in any process for development

of a standard for energy requirements in buildings are the need to

establish and motivate a sufficiently broad consortium of building interests to accomplish a task of this complexity and the need to create an

evolutionary type document since considerably more technical information

is needed than now exists to define all of the performance requirements

for buildings and building equipment.

In our opinion, energy shortages are close enough at hand, and the

dependence of the United States on foreign energy resources is at such a

level as to warrant willing participation of all segments of the building

industry in developing an equitable set of guidelines for energy use in

buildings

163
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REFERENCES

1. Patterns of Energy Consumption in the United States,

Stanford Research Institute, January 1972.

2. NBS report is in preparation.

3. Pittsburgh Plate Glass Industries, Technical Service

Report No. 105-B.

4. American Society of Heating, Refrigerating and Air

Conditioning Engineers, (ASHRAE) , 345 East 47th Street,

New York, New York 10017.

5. Mechanical and Electrical Equipment for Buildings,

McGuinness, W. J., and B. Stein, fifth edition, John Wiley

& Sons, 1971.

6. "Minimization of Residential Energy Consumption," Harvey,

D. G. , Kudrick, J. A., and G. Leigh ton, Proceedings of the

7th Intersociety Energy Conversion Engineering Conference,

San Diego California (1972.)

7. Adopted from IES Recommendations for the Better Utilization

of Energy Expended for Lighting, Illuminating Engineering

Society, 345 East 47th Street, New York, New York 10017.

8. "Determination of the Comfort Zone," Houghten, F. C, and

C. P. Yaglou, ASHVE Transactions, Vol. 29, pg. 361, 1923.

9. "The Nature of Thermal Comfort for Sedentary Man," Nevins

,

R. G., and F. H. Rohles, ASHRAE Transactions, Vol. 77,

Part 1, 1971.

10. Danish Technical Press, Copenhagen, 1970.

11. NBSLOD, Heating and Cooling Load Calculation Program, T. Kusuda, NBS report in preparation.

12. Conservation and Better Utilization of Electric Power by

Means of Thermal Energy Storage and Solar Heating; Phase

III Progress Report, NSF/Rann/SE/GI27976/PR73/l (March 1973)

13. From public address by Fred S. Dubin, Consulting Engineer,

(Dubin, Mindell and Bloom Associates, 42 W. 39th Street,

New York, New York 10018) San Francisco, 1972.

14. "The use of Solar Energy for Residential Space Heating,"

H. G. Lorsch, Energy Conversion, vol. 13, 1973.

15. Federal Council on Science and Technology Committee on Energy Research and Development Subpanel Report on Total

Energy, available through National Technical Information

Service.

173

* U. S. GOVERNMENT PRINTING OFFICE : 1973—542-647/1
FORM NBS-114A (1-71) 2. Gov t Accession No.

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

PUBLICATION OR REPORT NO. NBS TN-789

3. Recipient's Accession No.

4. TITLE AND SUBTITLE Technical Options for Energy Conservation in Buildings

5. Publication Date July 1973

6. Performing Organization Code

7. AUTHOR(S)

Building Environment Division, CBT

8. Performing Organization

10. Project/Task/Work Unit No. 4601130

9. PERFORMING ORGANIZATION NAME AND ADDRESS NATIONAL BUREAU OF STANDARDS DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

1 1. Contract/Grant No.

12. Sponsoring Organization Name and Address National Conference of States for Building Codes and Standard^

and National Bureau of Standards

Center for Building Technology

National Bureau of Standards, Washington, D. C. 20234

13. Type of Report & Period CoveredFinal

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or literature survey, mention it here.) The purpose of this report is to provide reference material on the technical options

for energy conservation in buildings. It was prepared for the National Conference

of States for Building Codes and Standards -National Bureau of Standards Joint Emer- gency Workshop on Energy Conservation in Buildings held at the U. S. Department of Commerce in Washington,D.C. on June 19, 1973. This report describes actions pertinent to existing buildings and new buildings.

Regarding existing buildings, principal topics include summer cooling, winter heating,

and other energy conserving features--!. e, , insulation, fenestration, lighting, appliances, domestic hot water, and human comfort. Suggested actions include those which

can be accomplished voluntarily or without expense, and also actions which require

some modest effort or expense on the part of the building owner or occupant.

Regarding new buildings, energy conservation actions are described that deal with

building design and mechanical systems. The report concludes with a summary a'f mechanisms for implementation of such actions and criteria for use in evaluation of

them.

17. KEY WORDS (Alphabetical order, separated by semicolons) Building design; energy conservation; mechanical systems.

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