Research Information Center

JSational Bureau of Standards

Gaithersburg, Maryland 20899

NBSIR 87-3594

JAN 6 1988

Fenestration Design for Buiiding

Atria

S. J. Treado

D. B. Holland

J. W. Bean

G. L. Gillette

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Building Physics Division

Gaithersburg, MD 20899

September 1987

Prepared for

U.S. Department of Energy

American Architectural Manufacturers Association

NBSIR 87-3594

FENESTRATION DESIGN FOR BUILDING

ATRIA

S. J. Treado

D. B. Holland

J. W. Bean

G. L Gillette

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Building Physics Division

Gaithersburg, MD 20899

September 1987

Prepared for; U.S. Department of Energy

American Architectural Manufacturers Association

U.S. DEPARTMENT OF COMMERCE, Clarence J. Brown, Acting Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
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ABSTRACT

The influence of fenestration design on building energy performance is

evaltaated, based on measurements in four atrium buildings and a series

of detailed computer simulations using TARP and CEL-1. The impact of

glazing area and solar-optical properties is examined for a linear and

central atrium building for eight geographical locations . The

usefulness of automatic solar shading and heat storage strategies is

also investigated. Guidelines are presented for effective design of

atrium fenestration.

• The results indicate that when daylighting is used, appropriate

fenestration design will result in lower building energy requirements

than would occur with no fenestration. Reductions in annual building

energy requirements of over 20 percent were observed, although the

total savings potential varied with geographical location.

Keywords: atrium; building energy; daylighting; glazing; heat storage;

solar shading

iii
FOREWORD

This report dociiments work performed for the American Architectural

Manufacturers Association and the U.S. Department of Energy, and is

part of a continuing research program investigating the effective use

of building fenestration and daylighting strategies.

iv
ACKNOWLEDGMENTS

The authors wish to acknowledge the advice and consultations provided

by Mr. J, W. Griffith and an AAMA technical group, and the

administrative assistance from the National Fenestration council and

Mr. W. Birch. Special appreciation goes to Mrs. Donna Shoemaker and

Mrs. Beth Burdette for typing and editing this manuscript.

DISCLAIMER

References to any commercial equipment or materials are given to

describe the conduct of the research, and do not imply recommendation

or endorsement by the National Bureau of Standards.

V
TABLE OF CONTENTS

Page

ABSTRACT iii

FOREWORD ....... . o . iv

ACKNOWLEDGMENTS .................... e « o .. v

DISCLAIMER v

TABLE OF CONTENTS vi

LIST OF TABLES vii

LIST OF FIGURES viii

1. INTRODUCTION 1

2. BACKGROUND 2

3. FIELD MEASUREMENTS OF ATRIUM CONDITIONS 3

4. COMPUTER SIMULATION OF ATRIUM PERFORMANCE 6

4.1 Linear Atrium Building Simulation 6

4.2 Square Atrium Building Simulation 8

4.3 Simulation Locations 9

4.4 Simulation Variation of Parameters 9

4.5 Daylighting Simulations 13

4.6 Simulation Output '. 14

5. COMPUTER SIMULATION RESULTS 16

5 . 1 Los Angeles 18

5.2 Lake Charles 18

5.3 El Paso 19

5.4 Nashville 20

5.5 Seattle 20

5 . 6 New York 20

5 . 7 Omaha 20

5.8 Madison 21

5.9 Glazing Absorptance 21

5.10 Lighting Power Density 21

6. CONCLUSIONS 23

7. REFERENCES 25
LIST OF TABLES

Page

Table 1 . Atrium Measurement Buildings 3

Table 2. Variables Measured - Building D 5

Table 3. Linear Atriiom Simulation Building 6

Table 4. Square Atrium Simulation Building 8

Table 5. Simulation Locations 9

Table 6. Values for Parametric Studies 10

Table 7. Parameter Values for Each Simulation 11

Table 8. Daylighting CU Pre-Calculations 13

Table 9. Surface Reflectance Values for Atrium Buildings .. 14

vii
LIST OF FIGURES

Figure 1 . Temperature variations in building A atrium

(Hughes Justice Complex) 27

Figure 2. Temperature variations in buildings B and C

(Enerplex North and South) 28

Figure 3 . Hourly temperature variations in building D

(AT6eT Long Lines) 29

Figure 4. Hourly irradiance and illuminance levels in

building D (AT&T Long Lines) 30

Figure 5 . Linear atrium building 31

Figure 6. Square atrium building 32

Figure 7a. Total energy ratio for transmittance of 0.8,

linear atrium 33

Figure 7b. Total energy ratio for transmittance of 0.5,

linear atrium 34

Figure 7c. Total energy ratio for transmittance of 0.2,

linear atrium 35

Figure 8a. Total energy ratio for transmittance of 0.8,

square atrium .' 36

Figure 8b. Total energy ratio for transmittance of 0.5,

square atrium 37

Figure 8c . Total energy ratio for transmittance of 0.2,

square atrium 38

Figure 9a. Total energy ratio with solar shading, heat

storage and single pane, linear atrium 39

Figure 9b. Total energy ratio with solar shading, heat

storage and single pane, square atrium 40

Figure 10a. Total energy versus glazing area and transmittance, Los Angeles, linear atrium 41

Figure 10b. Heating, cooling and lighting energy versus

glazing area and transmittance, Los Angeles,

linear atrium 42

viii
Figure 10c. Peak heating and cooling loads versus glazing

area and transmittance, Los Angeles,

linear atrium 43

Figure lOd. Energy usage versus glazing transmittance,

Los Angeles , linear atrium 44

Figure lOe. Energy usage with solar shading, heat storage

and single pane glazing, Los Angeles,

linear atrium 45

Figure 11a, Total energy versus glazing area and transmittance, Los Angeles, square atrium 46

Figure lib. Heating, cooling and lighting energy versus

glazing area and transmittance, Los Angeles,

square atrium 47

Figure 11c. Peak heating and cooling loads versus glazing

area and transmittance, Los Angeles,

square atrium 48

Figure lid. Energy usage versus glazing transmittance,

Los Angeles , square atriiam 49

Figure lie. Energy usage with solar shading, heat storage

and single pane glazing, Los Angeles,

square atrium 50

Figiire 12a. Total energy versus glazing area and transmittance, Lake Charles, linear atrium ......... 51

Figure 12b. Heating, cooling and lighting energy versus

glazing area and transmittance. Lake Charles,

linear atrium 52

Figure 12c. Peak heating and cooling loads versus glazing

area and transmittance , Lake Charles

,

linear atrium 53

Figure 12d. Energy usage versus glazing transmittance.

Lake Charles , linear atrium 54

Figure 12e. Energy usage with solar shading, heat storage

and single pane glazing. Lake Charles,

linear atrium 55

Figure 13a. Total energy versus glazing area and transmittance, Lake Charles, square atrium 56

ix
Figure 13b. Heating, cooling and lighting energy versus

glazing area and transmittance, Lake Charles,

square atrium 57

Figure 13c. Peak heating and cooling loads versus glazing

area and transmittance , Lake Charles

,

square atrium 58

Figure 13d. Energy usage versus glazing transmittance.

Lake Charles, square atrium 59

Figure 13e. Energy usage with solar shading, heat storage

and single pane glazing. Lake Charles,

square atrium 60

Figure 14a. Total energy versus glazing area and transmittance, El Paso, linear atrium 61

Figure 14b. Heating, cooling and lighting energy versus

glazing area and transmittance, El Paso,

linear atrium 62

Figure 14c. Peak heating and cooling loads versus glazing

area and transmittance, El Paso,

linear atrium 63

Figure 14cU Energy usage versus glazing transmittance,

El Paso, linear atrium 64

Figure 14e. Energy usage with solar shading, heat storage

and single pane glazing, El Paso,

linear atrium 65

Figure 15a. Total energy versus glazing area and transmittance, El Paso, square atrium 66

Figure 15b. Heating, cooling and lighting energy versus

glazing area and transmittance, El Paso,

square atrium 67

Figure 15c. Peak heating and cooling loads versus glazing

area and transmittance, El Paso,

square atrium 68

Figure 15d. Energy usage versus glazing transmittance,

El Paso, square atrium 69

Figure 15e. Energy usage with solar shading, heat storage

and single pane glazing, El Paso,

square atrium 70

X
Figure 16a. Total energy versus glazing area and transmittance, Nashville, linear atrium 71

Figure 16b. Heating, cooling and lighting energy versus

glazing area and transmittance, Nashville,

linear atrium 72

Figure 16c. Peak heating and cooling loads versus glazing

area and transmittance, Nashville,

linear atrium 73

Figure 16d. Energy usage versus glazing transmittance,

Nashville, linear atrium 74

Figure 16e. Energy usage with solar shading, heat storage

and single pane glazing, Nashville,

linear atrium 75

Figure 17a. Total energy versus glazing area and transmittance, Nashville, square atrium 76

Figure 17b. Heating, cooling and lighting energy versus

glazing area and transmittance, Nashville,

square atrium 77

Figure 17c. Peak heating and cooling loads versus glazing

area and transmittance, Nashville,

square atrium 78

Figure 17d. Energy usage versus glazing transmittance,

Nashville, square atrium 79

Figure 17e. Energy usage with solar shading, heat storage

and single pane glazing, Nashville,

square atrium 80

Figure 18a. Total energy versus glazing area and transmittance, Seattle, linear atrium 81

Figure 18b. Heating, cooling and lighting energy versus

glazing area and transmittance, Seattle,

linear atrium 82

Figure 18c. Peak heating and cooling loads versus glazing

area and transmittance, Seattle,

linear atrium 83

Figure 18d. Energy usage versus glazing transmittance,

Seattle, linear atrium 84

xi
Figure 18e. Energy usage with solar shading, heat storage

and single pane glazing, Seattle,

linear atrium 85

Figure 19a. Total energy versus glazing area and transmittance, Seattle, square atrium 86

Figure 19b. Heating, cooling and lighting energy versus

glazing area and transmittance, Seattle,

square atrivim 87

Figure 19c. Peak heating and cooling loads versus glazing

area and transmittance, Seattle,

square atrium 88

Figure 19d. Energy usage versus glazing transmittance,

Seattle, square atrium 89

Figure 19e. Energy usage with solar shading, heat storage

and single pane glazing, Seattle,

square atrium 90

Figure 20a. Total energy versus glazing area and transmittance, New York, linear atrium 91

Figure 20b. Heating, cooling and lighting energy versus

glazing area and transmittance. New York,

linear atrium 92

Figure 20c. Peak heating and cooling loads versus glazing

area and transmittance, New York,

linear atrium 93

Figure 20d. Energy usage versus glazing transmittance.

New York, linear atrium 94

Figure 20e. Energy usage with solar shading, heat storage

and single pane glazing. New York,

linear atrium 95

Figure 21a. Total energy versus glazing area and transmittance, New York, square atrium 96

Figure 21b. Heating, cooling and lighting energy versus

glazing area and transmittance, New York,

square atrium 97

Figure 21c. Peak heating and cooling loads versus glazing

area and transmittance. New York,

square atrium 98

xii
99

Figure 21d. Energy usage versus glazing transmittance,

New York, square atrium

Figure 21e. Energy usage with solar shading, heat storage

and single pane glazing, New York,

square atrixim 100

Figure 22a. Total energy versus glazing area and transmittance, Omaha, linear atrium 101

Figure 22b. Heating, cooling and lighting energy versus

glazing area and transmittance, Omaha,

linear atrium 102

Figure 22c. Peak heating and cooling loads versus glazing

area and transmittance, Omaha, linear atrium .. 103

Figure 22d. Energy usage versus glazing transmittance,

Omaha, linear atritim . 104

Figure 22e. Energy usage with solar shading, heat storage

and single pane glazing, Omaha,

linear atrium 105

Figure 23a. Total energy versus glazing area and transmittance, Omaha, square atrium 106

Figure 23b; Heating, cooling and lighting energy versus

glazing area and transmittance, Omaha,

square atrium 107

Figure 23c. Peak heating and cooling loads versus glazing

area and transmittance, Omaha, square atrium . . 108

Figure 23d. Energy usage versus glazing transmittance,

Omaha, square atrium 109

Figure 23e. Energy usage with solar shading, heat storage

and single pane glazing, Omaha,

square atrium 110

Figure 24a. Total energy versus glazing area and transmittance, Madison, linear atrium Ill

Figure 24b. Heating, cooling and lighting energy versus

glazing area and transmittance, Madison,

linear atrium 112

Figure 24c. Peak heating and cooling loads versus glazing

area and transmittance, Madison,

linear atrium 113

xiii
114

Figure 24d. Energy usage versus glazing transmittance,

Madison, linear atrium

Figure 24e. Energy usage with solar shading, heat storage

and single pane glazing, Madison,

, linear atrium 115

Figure 25a. Total energy versus glazing area and transmittance, Madison, square atrium 116

Figure 25b. Heating, cooling and lighting energy versus

glazing area and transmittance, Madison,

square atrium 117

Figure 25c. Peak heating and cooling loads versus glazing

area and transmittance, Madison,

square atrium 118

Figure 25d. Energy usage versus glazing transmittance,

Madison, square atrium 119

Figure 25e. Energy usage with solar shading, heat storage

and single pane glazing, Madison,

square atrium 120

Figure 26a. Energy usage versus glazing absorptance,

linear atriiim, Los Angeles 121

Figure 26b. Energy usage versus glazing absorptance,

linear atrium. Lake Charles 122

Figure 26c. Energy usage versus glazing absorptance,

linear atrium, El Paso 123

Figure 26d. Energy usage versus glazing absorptance,

linear atrium, Nashville 124

Figure 26e. Energy usage versus glazing absorptance,

linear atrium, Seattle 125

Figure 26f. Energy usage versus glazing absorptance,

linear atrium. New York 126

Figure 26g. Energy usage versus glazing absorptance,

linear atrium, Omaha 127

Figure 26h. Energy usage versus glazing absorptance,

linear atrium, Madison 128

Figure 27a. Total energy ratio vs lighting power density,

Los Angeles 129

xiv
130

Figure 27b. Heating, cooling and lighting energy vs

lighting power density, Los Angeles

Figure 27c. Peak heating and cooling loads vs lighting

power density, Los Angeles 131

Figure 28a. Total energy ratio vs lighting power density.

Lake Charles 132

Figure 28b. Heating, cooling and lighting energy vs

lighting power density. Lake Charles 133

Figure 28c. Peak heating and cooling loads vs lighting

power density. Lake Charles 134

Figure 29a. Total energy ratio vs lighting power densi ty,

El Paso 135

Figure 29b. Heating, cooling and lighting energy vs lighting power density, El Paso 136

Figure 29c. Peak heating and cooling loads vs lighting

power density, El Paso 137

Figure 30a. Total energy ratio vs lighting power density,

Nashville 138

Figure 30b. Heating, cooling and lighting energy vs lighting power density, Nashville 139

Figure 30c. Peak heating and cooling loads vs lighting

power density, Nashville 140

Figure 31a. Total energy ratio vs lighting power density,

Seattle 141

Figure 31b. Heating, cooling and lighting energy vs lighting power density, Seattle 142

Figure 31c. Peak heating and cooling loads vs lighting

power density, Seattle 143

Figure 32a. Total energy ratio vs lighting power density,

New York 144

Figure 32b. Heating, cooling and lighting energy vs lighting power density. New York 145

Figure 32c. Peak heating and cooling loads vs lighting

power density, New York 146

XV
Figure 33a. Total energy ratio vs lighting power density,

Omaha 147

Figure 33b. Heating, cooling and lighting energy vs

lighting power density, Omaha 148

Figure 33c. Peak heating and cooling loads vs lighting

power density, Omaha 149

Figure 34a. Total energy ratio vs lighting power density,

Madison 150

Figure 34b. Heating, cooling and lighting energy vs

lighting power density, Madison 151

Figure 34c. Peak heating and cooling loads vs lighting

power density, Madison 152

xvi
1 . INTRODUCTION

The inclusion of atrium spaces in buildings has been increasing in

recent years for several reasons. Building atria are dramatic

architectural features, providing for a significant change of scale

within the enclosing structure, and allowing flexibility in interior

layout. The aesthetic qualities of building atrium spaces are

difficult to overlook, and atria can provide for large volumes of

interior space at a relatively modest cost. Atria can also be

efficiently incorporated with airflow and smoke control strategies

However, perhaps the most important atrium performance aspect is the

ability of atria to allow significant amounts of daylight to penetrate

building interior spaces. Indeed, one of the most pleasing uses of

atrium spaces involves the replication of an attractive park- like

setting within a controlled interior environment, complete with trees,

plants and flowers. While the psychological benefits of interior

daylight are well documented, building energy benefits through daylight

utilization are also possible .[ 1 , 2]

This report examines the daylighting and energy performance of building

atrium spaces, based on measurements in four buildings and a series of

computer simulations using the TARP (Thermal Analysis Research Program)

and CEL-1 (Conservation of Electric Lighting) computer programs. The

results are analyzed and guidelines are presented to aid building

designers in designing effective atrium spaces. The focus of the

analysis is on the best use of atrium fenestration, particularly

glazing characteristics. The use of solar shading and heat storage

strategies is also examined. The effect of atrium design on energy

usage for heating, cooling and lighting, and peak heating and cooling

loads, is examined.

1
2 . BACKGROUND

In the design of buildings, the determination of the most effective

combination of envelope components requires considerable effort.

Consideration must be given to the influences of geographical location,

building type and size, site constraints and occupant related factors.

The dependence of building energy requirements for heating, cooling,

lighting and equipment on the thermal properties of the building

envelope and internal loads makes it difficult to determine an optimal

design. Many times, an envelope feature may increase one form of

energy use for building conditioning, but decrease another. In

particular, when fenestration is considered, different glazing sizes or characteristics will affect energy usage for heating, cooling and

lighting, and an optimum design can only be determined by evaluating

the net performance. To aid in the selection of the most effective

fenestration design, various design alternatives can be compared using

an hour-by-hour building energy computer simulation for a t3rpical year.

Such a computer program simulates the dynamic thermal and energy

performance of a building, which is represented by a suitable input

file containing a description of building components, equipment,

operating schedules and occupancy patterns , along with a computer tape

of weather conditions.

With regard to the problem at hand, while building energy simulation

computer programs have been utilized successfully for many different

building types , it is essential that the validity of a particular

program for evaluating atrium performance be established to ensure that

any conclusions drawn from the simulations are themselves valid.

However, it is nearly impossible to validate ail aspects of a detailed

building energy simulation program, due to the complexity of the

programs and the difficulty in obtaining accurate thermal and energy

performance measurements of occupied buildings over a long time.

The focus of this study is on the evaluation of fenestration design on

building atrium performance, including the impact of daylight

utilization to offset electric lighting requirements. Thus, accurate

procedures for computing interior daylight levels are required, along

with appropriate routines for modeling thermal processes within the

atrium and surrounding space. A limited set of measurements were taken

to provide information about daylight levels and energy flows with

atrium spaces, to assist in the development of the appropriate computer

algorithms for modeling buildings with atrium spaces. These

measurements, and the subsequent simulations and results, are described

in the succeeding sections.

2
A literature search uncovered few prior detailed studies of atria, but

did yield some data on atrium performance .[ 3-9 ] The smoke control

characteristics and qualitative evaluation of HVAC performance and air

flow patterns in building atria were described, as were some aspects of

HVAC design for atria.

3. FIELD MEASUREMENTS OF ATRIUM CONDITIONS

Systematic measurements were taken in four buildings containing a total

of six atria The purpose of the measurements was to obtain a feel for

thermal and visual conditions within some atrium buildings , and to

compile data for comparison to computer calculations . A brief

description of each building is given in table 1

Table 1. Atrium Measurement Buildings

A. Hughes Justice Complex

Trenton, New Jersey

8 floor central atrium, fully conditioned

B. Enerplex North

Plainsboro, New Jersey

3 floor, south facing atrium with heat recovery

3 floor central, linear light well, fully conditioned

C. Enerplex South

Plainsboro, New Jersey

3 floor, north facing atrium, unconditioned

3 floor central, linear light well, fully conditioned

D. AT&T Long Lines Building

Oakton, Virginia

3 floor linear atrium, fully conditioned

Temperatures were measured within the atrium and adjacent spaces to

assist the modeling effort. Of particular concern was the extent of

vertical temperature stratification in the atrium, since TARP (and

other simulation programs) treat each thermal zone as having uniform

air temperature at any instant in time. If significant variations in

atrium air temperature with vertical location were observed, special

modeling procedures would be required. Additional measurements of

surface temperatures, daylight levels and solar radiation levels were

intended to provide a general picture of thermal and illumination

conditions within the atrium spaces

Measurements were conducted by hand in buildings A, B and C over a twoday period using thermometers, illuminance meters, irradiance meters

and spot radiometers. With generally clear skies (global irradiance of

260 Btu/h ft (820 wm"^) and an outdoor temperature of 84°F (29°C) , air

temperature within the eight ft (2.44m) floor atrium in building A

3
averaged about 71°F (22°C) . The maximum air temperature was 74°F

(23°C) at the eighth floor level, while the minimum was 68°F (20°C) at

floors five through seven. However, the variation in air temperature

with horizontal location on any floor averaged 3°F (1.7®C). Thus, as shown in figure 1, vertical temperature variations were very similar to

horizontal temperature variations, with most of the stratification

occurring at the top floor of the atriiim. In the same figure, atrium

wall surface temperature is seen to vary through a considerably wider

range, due to the incidence of solar radiation. The underside of the

atrium glazing was approximately 100°F (38®C) . The variation in air

temperature with horizontal location can be attributed to the proximity

to the air supply registers on each floor.

The results of similar measurements in buildings B and C are shown in

figure 2. Outdoor air temperature was 79®F (26°C) with a global

irradiance of 257 Btu. h"^ ft”^ (810 wm“^) . Building B is a specially

designed structure with heat collection from the south- facing atrium,

underground rock storage and airflow double -wall construction on the

north face. [3] However, the forced air circulation system was not in

operation at the time of the measurements because the building was not

yet completed or occupied. Surface temperatures ranged from 75°F to

79,5°F (23.9 to 26,4®C). Air temperature within the unconditioned

central atrium/lightwell varied from 74®F (23.3°C) at the floor to

79.5®F (26.4°C) near the top. Building C had a north- facing

unconditioned sianspace, which had air temperatures ranging from 77 to

80°F (25° to 26.7°C) vertically. The central atrium/lightwell, which

was conditioned, ranged in temperature from 71 to 75.5°F (21.7 to

24.2°C), with most of the increase occurring near the top of the space.

The most detailed measurements were taken in building D, the AT&T Long

Lines building. Automated measurement equipment was installed and data

were collected hourly for a period of one month. Table 2 lists the

variables measured.

4
Table 2. Variables Measured - Building D.

1. Glazing surface temperature

2. Outdoor air temperature

3. Third floor air temperature

4. Third floor wall temperature

5. Second floor air temperature

6. Second floor wall temperature

7. First floor air temperature

8. First floor wall temperature

9 . Return air temperature

10. Atrium floor temperature

11. Exterior global irradiance , 12. Vertical irradiance, third floor

13. Vertical illuminance, third floor

14. Vertical irradiance, second floor

15. Vertical illuminance, second floor

16. Vertical irradiance, first floor

17. Vertical illuminance, first floor

18. Horizontal irradiance, first floor

19. Horizontal illuminance, first floor

20. Glazing luminance, zenith

Figure 3 displays hourly temperature variations for a typical

Slimmer day. The outdoor air temperature reached a high of 90°F

(32.2®C) and ranged as low as 61®F (16.1®C), The maximum vertical

temperature stratification was observed to be 5°F (2.8®C) from the

first to third floors, while the first and second floors differed by

only 1°F (.6°C). Third floor wall surface temperature ranged as high

as 77.5°F (25.3°C). Figure 4 shows the various illuminance and

irradiance levels observed on the same day. Considerable variations

over time are apparent, as would be expected. Light levels on a horizontal surface near the atrium floor exceed 93 fc (1000 lux) for

most of the day, and peak at over 279 fc (3000 lux). Solar radiation

levels at the same location follow a similar pattern, exceeding .95

Btu/hft^ (3 wm"^) for most of the day, and peaking at over 30 wm”^.

Several general conclusions can be drawn from these measurements.

First, in fully conditioned atrium spaces vertical temperature

variations, or stratification, is similar in magnitude to horizontal

variations. Thus, modeling the atrium space as a single thermal zone

should not introduce any more uncertainty due to stratification than

due to typical variations encoiintered in non-atrium spaces. Second,

irradiance and illuminance levels can be high in large glazed atria,

with significant heating of wall surfaces due to absorption of solar

radiation. Third, most of the elevated atrium air and surface

temperatures occur near the top of the atrium, in conditioned atria.

5
4. COMPUTER SIMULATION OF ATRIUM PERFORMANCE

The computer simulations of atrium building performance were

implemented using custom versions of TARP and CEL-1, TARP is a detailed thermal analysis program, [10] while CEL-1 is a detailed

lighting and daylighting simulation program. [ 11 , 12] Two types of three

story buildings with atrium spaces were simulated, namely a linear

atrium and a central, square atrium. Simulations were performed for

eight geographical locations, four glazing areas , three glazing

transmittances , two glazing absorptances , and three lighting power

densities, for single and double glazings. Solar shading and heat

storage strategies were also simulated. Not all combinations of

parameters were simulated, with the main emphasis being given to

glazing area and transmittance. Other combinations were selected to

reflect what were considered to be the most useful configurations,

while still allowing the determination of the sensitivity of the

results to all the various parameters. Thirty-eight simulations were

run for each location for a total of 304 simulations.

4.1 LINEAR ATRIUM BUILDING SIMULATION

The largest number of simulations were executed for a three floor

building with a linear atrium. As shown in figure 5, this building was

150 by 120 feet (45.72 by 36.576m), with a linear atrium 30 ft (9.14m)

wide, situated in the center of the building along a north-south axis

and extending ten feet (3.048m) above the roof to a total height of 40

feet (12.192m). The three floors on each side of the atriiam were

without walls for a distance of 30 feet (9.144m) from the atrium, so light from the atriiam could penetrate those areas. An additional 30

feet (9.144m) of office space was located beyond an opaque wall on each

side extending to the building exterior walls. Thus, no portion of the

office space was more than 30 feet (9.144m) from either the atrium or exterior wall, the latter being 30 per cent glazed. The floor- to-floor

height of each story was 10 feet (3.048m), with a floor to ceiling

height of 8 feet (2.4m). Pertinent information regarding the linear

atrium building is summarized in table 3.

Table 3. Linear Atrium Simulation Building

1. Exterior dimensions 120 by 150 by 30 ft

(37x46x9m)

2. Atrium dimensions 120 by 30 by 40 ft

(37x9xl2m)

3. Floor area-office space

-atrium

43,200 ft2 (4013m2)

3,600 ft2 (334m2)

4, Exterior wall construction 4' (1.22m) Face Brick

1/2" (.0127m)

Cement Mortar

6
8" (.2032m)

Cinder Block

2" (,0508m)

Poly Insulation

1/2" (.0127m)

Gypsum Drywall

5 . Roof Construction 3/8" (.009525m)

Bui1 tup Roof

2" (.0508m)

Rigid Insulation

2" (.0508m)

Concrete Slab

3/4" (.019m) Air Space

3/4" (.019m)

Metal Lath

1/2" (.0127m)

Gypsum Drywall

6, Occupant density 1/90 persons/ft^

(1/8.361 persons/m^)

7. Electrical equipment power density 1.5 watts/ft^

(16.146 w/m^)

8. Temperature control

12-6 a.m. 6 a.m.-6 p.m.* 6-12 p.m.

Heating 60F (15.55C) 68F (20C) 60F (15.55C)

Cooling 85F (29.44C) 78F (25.55C) 85F (29.44C)

* Workdays only

9 . Occupancy schedule

12-6 a.m. 6-7 a.m. 7 a.m. -5 p.m. 5-6 p.m. 6-12 p.m.

0 .5* 1* .5* 0 * Workdays only

10. Illuminance Setpoint - atrium 120 fc (1292 lux)

- offices 80 fc ( 861 lux)

11. Heating Efficiency - 0.80, Cooling COP - 3.0

A general fluorescent lighting system was modeled, with the base runs

using a lighting power density of 2 watts/ft^ (21.6 w/m^) . Other

lighting power densities were also simulated, as described in a later

section on parametric variations. A conditioned basement was modeled

beneath the entire building. The exterior wail fenestration, on the

east and west facades, was fixed for ail the simulations. The atrium

fenestration, however, was varied extensively, as is described later.

Daylight utilization was simulated for all parts of the building. The

details of the daylighting calculation procedures are also described

later. The setpoint of 120 fc (1292 lux) for the atrium was chosen to

7
provide adequate light for indoor plants, based on information from

U.S. Department of Agriculture publications .[ 13 , 14]

4.2 SQUARE ATRIUM BUILDING SIMULATION

The square atriiam simulation building was similar to the linear atrium

building in most respects, except for the geometrical layout. As shown

in figure 6, the exterior dimensions of the building were 180 by 180 ft

(54o 9x54. 9m) , with a central atrium of 60 by 60 feet (18 . 3x18 . 3m) . The

portions of the office space within 30 feet (9.144m) of the atrium were

open plan to allow the penetration of daylight from the atrium. The

outside 30 feet (9.144m) of the building was separated on all sides

from the inner portion of the building by an opaque wall. Thus, no

portion of the office space was more than 30 feet (9.144m) from either

the atrium or the exterior wall windows. The floor areas of the square

and linear atrium spaces were identical; however, the square atrium

building had more office space. Details of the square atrium

simulation building are contained in table 4.

Table 4. Square Atrium Simulation Building

1. Exterior dimensions 180 by 180 by 30 ft.

(54.9x54.9x9 . Im)

2. Atriijm dimensions 60 by 60 by 40 ft.

(18. 3x18. 3x12. 2m)

3. Floor area - office space 86,400 ft2 (8027m^)

- atrium 3,600 ft2 (334m2)

4. Exterior wall construction 4' (1.22m) Face Brick

1/2" (.0127m)

Cement Mortar

8" (.2036m)

Cinder Block

2" (.0508m)

Poly Insulation

5. Roof Construction 3/8" Builtup Roof

(.009525m)

2" Rigid Insulation

(.0508m)

2" Concrete Slab

(.0508m)

1/2" (.0127m)

Gypsum Drywall

3/4" (.019m) Air Space

3/4" (.019m) Metal Lath

1/2" (.0127m)

Gypsum Drywall

6. Occupant density 1/90 persons/ft^

8
(1/8.361 persons/m^)

7. Electrical equipment power density 1.5 watts/ft^

(16 , 146w/m^)

8. Temperature control

12-6 a.m. 6 a.m,-6 p.m.* 6-12 p.m.

Heating 60F (15.55C) 68F (20C) 60F (15.55C)

Cooling 85F (29.44C) 78F (25.55C) 85F (29.44C) * Workdays only

9 . Occupancy schedule

12-6 a.m. 6-7 a.m. 7 a.m. -5 p.m. 5-6 p.m. 6-J.2 p.m.

0 .5* 1* .5* 0 * Workdays only

10. Illuminance Setpoint - atrium 120 fc (1292 lux)

- offices 80 fc ( 861 lux)

11. Heating Efficiency - 0.80, Cooling COP - 3.0

4.3 SIMULATION LOCATIONS

Simulations were executed for eight geographical locations, chosen to

cover a wide range of climate conditions. The locations, and their

heating and cooling degree days, are listed in table 5.

Table 5. Simulation Locations

Degree Days (65F) (18.3°C)

City Heating Cooling

Los Angeles , CA 1819 (1011) 615 (342)

Lake Charles , LA 1498 (832) 2739 (1522)

El Paso, TX 2678 (1488) 2098 (1166)

Nashville , TN 3696 (2053) 1694 (941)

Seattle, WA 5185 (2881) 129 (72)

New York, NY 5184 (2880) 861 (478)

Omaha , NB 6049 (3361) 1173 (652)

Madison, WI 7730 (4294) 460 (256)

4.4 SIMULATION VARIATION OF PARAMETERS

The primary emphasis of the variation of parameters was on atrium

glazing area and transmittance; however, numerous other parameters were

9
also varied. Table 6 lists the various values used for the parametric

studies

.

Table 6. Values for Parametric Studies

1. Fraction of Atrium Roof Glazed 0, 0.3, 0.6, 0.9

2. Glazing Transmittance 0.2, 0.5, 0.8

3. Number of Glazing Panes 1. 2

4. Glazing Absorptance 0.1, 0.4

5. Lighting Power Density 1, 2, 3 watts/ft^

(10.8, 21.5, 32.3w/m2)

6. Automatic Solar Shading Yes , No

7. Automatic Heat Storage Yes , No

10
Table 7 lists the values of each parameter for each of the 38

simulations executed per geographical location.

Table 7. Parameter Values for Each Simulation

Lighting

Glazing Glasing Number Power

Run

Area

Ratio

Transmittanceof

Panes

Atrium

Type

Solar

Shadinz

Heat

Storaee

Density

w/ft^

B 0

- - L N N 2

1 0.9 0.8 2 L N N 2

2 .6 .8 2 L N N 2

3 .3 .8 2 L N N 2

4 .9 .5 2 L N N 2

5 .9 .2 2 L N N 2

6 .6 .5 2 L N N 2

7 .6 .2 2 L N N 2

8 .3 .5 2 L N N 2

9 . 3 . .2 2 L N N 2

10 .9 .8 2 L Y N 2

11 .9 .8 1 L N N 2

12 .9 .8 1 L Y N 2

13 .9 .8 2 L N Y 2

14 .9 .8 2 L Y Y 2

15 0 - - S N N 2

16 .9 .8 2 s N N 2

17 .6 .8 2 s N N 2

18 .3 .8 2 s N N 2

19 .9 .5 2 s N N 2

20 .9 .2 2 s N N 2

11
21 .6 .5 2 S N N 2

22 ,6 .2 2 S N N 2

23 .3 .5 2 S N N 2

24 ,3 .2 2 S N N 2

25 .9 .8 2 S Y N 2

26 .9 .8 1 S N N 2

27 .9 .8 1 S Y N 2

28 .9 .8 2 S N Y 2

29 .9 .8 2 S Y Y 2

30 .9 ,8 2 L N N 3

31 .9 .8 2 L N N 1

32 0

- - L N N 1

33 .3 .8 2 L N N 3

34 .3_, .8 2 L N N 1

35 0 - - L N N 3

37 .9 .2 2 L N N 2

38

Key:

.3

L- linear.

.2

S- square

,

2

N-no

,

L

Y-yes

N N 2

The base cases , used for comparison and as normalization factors , are

atrium- type spaces with solid, opaque, insulated roofs. Thus the

volume and geometrical configuration of the baseline buildings are

identical to the buildings with glazed atriiam spaces . Separate base

runs were made for each building type and lighting power density (runs

B, 15, 32, and 35). The rationale for using this type of baseline

building was the desire to maintain a constant building size and

configuration, particularly with respect to floor area and enclosed

volume

.

Several of the parameters merit additional description. The solar

shading option refers to a simplified automatic control function

designed to simulate the performance of a movable shading system. This

shading system deploys to reduce glazing transmittance to 20 percent

12
when the atrium is in the cooling mode, thereby reducing solar

radiation gain into the atrium. Shading is activated if the following

conditions are met. First, the sun must be above the horizon. Second,

either the outdoor air temperature must exceed the atrium maximum air

temperature set-point, or cooling must have been used the previous

hour. This shading strategy mimics the performance of operable shades

or louvers , but is not an optimal shading technique . Such an optimal

technique would shade as required to minimize energy usage, using a continuous range of transmittances . The intent of the shading strategy

was to allow the evaluation of the potential of a simple shading

system.

The heat storage option is intended to simulate the performance of

thermal storage techniques such as air circulation through rock beds

,

phase change materials or direct gain thermal mass. The heat storage

option is activated only when the outdoor air temperature is below the

minimum atrium air temperature set-point, at which time any excess heat

which would become a cooling load is shifted into storage. Losses from

storage are taken to be 10 percent per hour, so heat stored one day

cannot be used the next, but can be reclaimed if a heating load occurs

while some heat remains in storage. The heat storage option is

intended to reduce overheating in the atrium during cool or cold days,

and to allow reclamation of some of the heat when needed. Heat storage

was not allowed on hot days, since it would represent unreasonable free

cooling. The three levels of lighting power density are ail used with

the same illumination set-points, thus simulating lighting systems of

varying luminous efficacy.

4.5 DAYLIGHTING SIMULATIONS

The effects of daylight utilization were modeled using specially

designed versions of TARP and CEL-1. CEL-1 was used to compute

daylight coefficients of utilization (CU's) throughout the building

interior. CU is defined as the ratio of interior to exterior

illuminance on a horizontal plane. A matrix of. CU's was pre-computed

for each point for three sl^ types, for various days and hours, as listed in table 8.

Table 8. Daylighting CU Pre-calculations

Sky T}rpes - clear, partly cloudy, overcast

Hours - 6, 8, 10, 12, 14, 16, 18

Days - one day each month

The matrix of CU's was made available to TARP as a computer file.

During its hourly loop, TARP selected the appropriate CU based on sky

type and month, interpolating in the hour dimension.

13
The accuracy of the daylighting CU's was validated by analytical

calculations and scale model measurements

.

Using the CU value and the hourly exterior global illuminance value,

determined from the global irradiance value from the weather tape and

luminous efficacy relations, daylight levels at each interior location

were computed for each hour. Then the lighting power needed to

maintain the required illuminance level was computed assuming a linear

relationship between electric lighting system power consumption and

light output. The luminaires were constrained to require a minimum of

30 percent of full lighting power. This simulates the performance of a photometrically controlled dimming or switching system. The calculated

lighting power was used for the thermal calculations

.

Table 9 displays the surface reflectance values for the atrium

buildings

.

Table 9 . Surface Reflectance Values for Atrium Buildings

Ceiling Reflectance 0.80

Wall Reflectance 0.50

Floor Reflectance 0.30

The atrium fenestration was modeled as a flat, horizontal surface of

non- diffusing glazing.

4.6 SIMUIATION OUTPUT

The simulation output included detailed information about heating,

cooling and lighting loads for each of the thermal zones , in monthly

and annual tabulations. This represents a great 'deal of information,

more than can be adequately discussed in a report of reasonable length.

However, the most important, and useful, results consist of a much

smaller subset of the total simulation output. In evaluating the

effect of fenestration design on atrium building energy performance,

the most important parameter probably is the total annual energy usage

for the entire building. Also of critical interest are the separate

breakdowns of heating, cooling and lighting energy, and peak heating

and cooling loads.

Total energy usage is of interest because it represents the amount of

energy required to operate the building as specified. Total energy

costs, however, require the weighting of each energy type by the

appropriate cost, since heating energy may be purchased as fuel, and

cooling and lighting energy as electricity. Due to the wide variations

and uncertainty in energy costs, dollar costs of energy were not

computed for this report. The reader can however, translate the

heating, cooling and lighting energy usage figures into energy costs

quite easily by using the appropriate energy unit costs. The effects

of peak heating and cooling loads on equipment sizing and demand

14
charges for energy are not explicitly examined; however, these factors

can be considered through reference to the peak load plots.

The conversion of the TARP-computed thermal loads into the associated

energy usages was accomplished using a simple model of a heating and

cooling system. A heating efficiency of 80 percent and a cooling

coefficient of performance of 3.0 were used to convert loads to energy.

While the performance of actiial heating and cooling systems may vary

somewhat from these simplified assiamptions , such a procedure is

adequate for assessing the relative performance of fenestration design

options. In addition, if a detailed systems model were used, it would

be logical to vary the system to match the expected loads , which change

with fenestration design.. Such a variation in heating and cooling

systems would tend to obscure the changes in energy requirements due to

fenestration design, which is the primary concern of the investigation.

15
5. COMPUTER SIMULATION RESULTS

In all cases, the simulation results indicated that the use of some

fenestration, along with daylight utilization, resulted in lower

building energy requirements than would occur if the atrium roof were

an insulated, opaque surface. For the linear atrium, see figures 7a, b

and c, the greatest percentage energy reductions occurred for the Los

Angeles location, about 20 percent, and the least for Madison, about

five percent. In general, the locations with higher ratios of cooling

energy to heating energy experienced greater decreases in total energy

requirements as atrium glazing area increased. This effect can be

attributed to the reductions in cooling and lighting energy with

fenestration usage, as will be shown in later figures. Figure 7 does

not include the solar shading or heat storage runs, which will also be

discussed later, and includes only double pane glazings, and lighting

power density of 2 watts/ft^ (21.5 w/m^)

.

It should be noted that while Los Angeles has the greatest percent

energy reductions , the absolute values of the energy reductions of some

of the other cities are similar. This is due to the fact that the

total energy requirements for Los Angeles are low compared to the other

locations. Thus, a ten percent reduction in energy usage for, say,

Nashville, may be similar to a 20 percent reduction in energy usage for

Los Angeles. It is the absolute energy savings that translates into

dollar savings.

A comparison of figures 7 a, b and c shows the glazing transmittance,

T, of 0.8 to be most effective for these simulations. This can be

attributed directly to the daylighting benefits of the increased

interior daylight levels. For the 0.8 transmittance, the total energy

curves are fairly flat in the glazing area ratio region 0.3 to 0.9.

This indicates that nearly equivalent energy performance would be

expected through a wide range of glazing areas, allowing the building

designer significant leeway in selecting glazing size. Slight minima

are seen at the 0:6 glazing area ratio for this transmittance. This is

due to interior daylight saturation, which occurs when interior

daylight levels meet or exceed the iliximination set-point, beyond which

no additional dimming of the lights is possible. For the lower

transmittances , the total energy ratios are lowest at the largest

glazing areas, particularly for the transmittance of 0.2. This can be

attributed to the fact that interior daylight levels did not saturate

at the smaller glazing sizes. The lowest transmittance was not

effective at the colder locations, as the daylighting benefits were

more than offset by the increased thermal losses with larger glazing

areas

.

Figure 8a, b and c contain similar information for the square atrium

building. The general trends are very similar to the linear building,

but the percentage energy reductions are larger. This is due to a slightly better utilization of daylight over a larger portion of the

office space adjacent to the atrium. For the transmittance of 0.8, the

total energy ratio curves are nearly flat between the glazing area

16
ratios of 0.6 and 0.9 indicating that daylight saturation begins to

occur near a glazing area ratio of 0.6. Larger glazing areas are more

effective for the lower transmittance values.

The effects of solar shading, heat storage and single versus double

pane glazings are summarized in figure 9,a for the linear atrium

building and 9b for the square atrium building. On these plots, the

abscissa is the log of the ratio of heating degree days to cooling

degree days for the indicated locations. The significance of the log

function is simply to compress the range of the horizontal axis.

Climates in which cooling dominates lie towards the left, and heating

dominated climates towards the right of these plots. In these plots,

glazing area ratio is fixed at 0.9, and transmittance at 0.8.

The best-performing options seem to be the double pane glazing with

heat storage, followed closely by the double pane with no special

features. As would be expected, single pane glazing is not effective,

particularly in the cold climates, and, surprisingly, the solar shading

was not beneficial. The reason for the poor performance of the solar

shading option, as will be discussed in greater detail later in this

report, is that while the shading decreased cooling requirements, it

also reduced daylighting benefits. This does not mean that another

shading strategy might not be effective, only that the strategy used in

these simulations did not reduce energy requirements. It did, however,

reduce direct solar gain into the atriiom and adjacent office spaces,

and thereby improved comfort conditions within those spaces. A more

energy effective shading strategy would have been to shade only enough

to minimize energy requirements for lighting and cooling, a significantly more complicated strategy to implement, although

certainly possible.

The effectiveness of the heat storage strategy can be traced to its

ability to reduce cooling and heating energy requirements on swing

days. That is, days when solar heating leads to cooling loads during

the daylight hours, but low outdoor air temperatur'es at night cause

heating loads. Instead of cooling on a sunny afternoon, excess heat is

stored and reclaimed when needed to heat the atrium at night.

The following sections describe in greater detail the results for each

geographic location. Included are the individual heating, cooling and

lighting energies, and peak heating and cooling loads.

17
5.1 LOS ANGELES

Figure 10a shows total energy ratio for the linear atrium building as a function of glazing area ratio and transmittance. The 0.8

transmittance is most effective, although not very different from the

0.5 transmittance. Ail glazing transmittances provided energy

reductions of nearly 20 percent or better.

The heating cooling and lighting energy breakdowns are shown in figure

10b, which indicates that most of the energy savings are due to reduced

lighting energy requirements. Cooling energy remains fairly constant,

except for the high transmittance glazing, which shows much higher

cooling requirements for large glazing areas. Heating energy doubles

for the low transmittance, large glazing area. However, heating loads

are negligible for Los Angeles, so this effect is inconsequential.

Figure 10c displays peak heating and cooling loads. Peak cooling loads

steadily increase with glazing area and transmittance, and are 15

percent greater for the high transmittance, large glazing area than for

no fenestration. Thus, the energy reductions shown in the previous

figures can only be achieved at the expense of larger peak cooling

loads, indicating that a compromise must be reached in selecting the

best glazing area. Higher peak loads mean more HVAC capacity and

higher demand charges. Peak cooling loads are only 10 percent higher,

or less, at the glazing area ratio of 0.6.

Figure lOd shows the variation in energy usage for the large glazing

area with various transmittances versus the base case (no

fenestration). Cooling energy increases, and lighting energy

decreases, for higher glazing transmittances, with total energy

exhibiting a minimum for a transmittance of 0.5. Solar shading, heat

storage and single pane glazing are compared in figure lOe. In this

figure, it can be seen that solar shading reduces cooling energy at the

expense of increasing lighting energy, compared to the non- shading

case. Heat storage reduces cooling energy without affecting lighting

energy, to provide the least total energy usage.

Figures 11a through e present the same results for the square atrium,

which are very similar to the linear atrium results. The percent

increase in peak cooling loads is less, because the baseline peak

cooling load is greater for the larger square atrium building.

5.2 LAKE CHARLES

Figure 12a shows the variation in total energy ratio with glazing area

and transmittance for the linear atrium building. Maximiam energy

reductions of nearly 20 percent are apparent, with the best performance

for the 0.8 and 0.5 glazing transmittances. The heating, cooling and

lighting energy breakdowns are displayed in figure 12b, where the

energy reductions are seen to be due to lower lighting energy

requirements. Cooling loads remain fairly constant, except for the

large glazing area with high transmittance. Heating energy

18
requirements increase with glazing area, particularly for the low

transmittance, however, heating energy usage remains small in relation

to cooling energy at this location.

In figure 12c, peak cooling loads increase gradually with glazing area,

being nearly 20 percent above the base case for the large glazing area

with high transmittance. Again, a compromise must be struck between

energy usage and peak loads . Peak heating load is unaffected by

glazing parameters, for the configurations studied.

Figures 12d and e reflect the same trends as for Los Angeles, except

heating energy is no longer negligible, albeit still relatively small.

The double pane with heat storage gives the best performance by a small

margin.

Figures 13a through e indicate similar results for the square atrium

building, although peak cooling loads increase by less than 10 percent

at their maximum. The double pane with and without heat storage gives

the best performances, with a glazing area ratio of 0.5 to 0.8.

5.3 EL PASO

El Paso climate produces cooling energy requirements over three times

greater than heating energy. In figure 14a, reductions in total energy

usage of 15 percent were possible for the high transmittance glazing

for all three glazing areas. All of the savings were due to lighting

energy reductions from daylighting. Heating and cooling energies

increased 'by 12 to 25 percent for the largest glazing area, while

lighting decreased to 60 percent, as shown in figure 14b. Peak cooling

loads were 20 percent higher for the large area, high transmittance

case, as indicated in figure 14c. Peak heating loads increased only

slightly.

The usual tradeoffs between lighting and cooling energy usage are

apparent in figure 14d, with the 0.5 transmittance using slightly less

total energy than the other transmittances for the large glazing area. Figure 14e displays the results for the special atrium features, where

the heat storage option is seen to require the least energy usage by a small margin.

Similar results for the square atrium building can be found in figures

15a through 15e, although slight reductions in cooling energy occurred

at the smaller glazing areas, and peak cooling loads increased less

than 10 percent at maximum.

19
5.4

NASHVILLE

As can be seen in figures 16a through 16e for the linear atrium and 17a

through 17e for the square atrium the results for Nashville are similar

to those for the previous cities. Nashville's climate, however,

produces heating energy requirements slightly greater than cooling

energy usage, a distinct departure from the earlier cities. Maximiom

energy savings of about 13 percent are seen at the 0.6 glazing area

with high transmittance. Peak cooling loads increase as much as 20

percent for the linear atrium and 10 percent for the square atrium.

5.5 SEATTLE

Figures 18a through 18e and 19a through 19e display the results for

Seattle for the linear and square atrium, respectively. Heating energy

is two and one-half times cooling energy for the base building.

Maximum energy reductions were about 12 percent, with nearly equal

performance for all glazing areas. Some cooling energy reductions were

observed through the use of small fenestration areas , exceeding five

percent for the square atrium. Heating energy usage increased

measurably with addition of glazing, but heat storage was effective.

5.6 NEW YORK

The New York results are presented in figures 20a through 20e for the

linear atrium and 21a through e for the square atrium. Heating energy

requirements were three times cooling energy usage for the base

building. ' Maximum reductions in total energy usage of ten percent were

observed, with little variation with glazing area. The 0.8

transmittance performed slightly better than the 0.5 transmittance.

Heating energy increased significantly for the large glazing areas, as did cooling energy for the high transmittance. , Peak cooling loads

increased significantly only for the high transmittance, large glazing

area. Heat storage was effective, but only slightly better than the

standard configuration (Run 1). Some cooling energy reductions were

seen for the square atrium building.

5.7 OMAHA

Figures 22a through 22e and 23a through 23e present the results for

Omaha for the linear and square atrium, respectively. Heating energy

usage for the baseline building was four times the cooling energy

requirements. Maximum reductions in total energy usage of eight

percent were observed, with little variation with glazing area. The

low transmittance glazing was not effective, due to higher heating

energy usage, and relatively moderate lighting energy reductions. Peak

cooling increased significantly for the high transmittance, large

glazing area. Heat storage was slightly more effective than the

standard configuration (Run 1).

20
5.8

MADISON

The Madison results are presented in figures 24a through 24e for the

linear atrium, and 25a through 25e for the square atrium. Heating

energy is six times the cooling energy for the baseline building.

Total energy reductions of four percent are seen, with slight variation

with glazing area. The low transmittance glazing was not effective at

reducing total energy usage. Maximum cooling energy is over 20 percent

greater for the high transmittance, large glazing area. Heating energy

increased as much as ten percent. Peak heating loads remained fairly

constant, but peak cooling loads increased significantly for the high

glazing transmittance. Heat storage was slightly more effective than

the standard configuration (Run 1). The single pane glazings were not

effective, nor were the low transmittance glazings.

5.9 GLAZING ABSORPTANCE

The effect of glazing absorptance was evaluated by varying that

parameter from 0.1 to 0.4 for the large and small glazing areas,

keeping transmittance to a constant 0.2. Thus the low transmittance

was maintained while varying the ratio of absorptance to reflectance.

Figures 26a through h display the resulting heating, cooling, lighting

and total energy requirements for each location. Examination of these

figures reveals that atrixom glazing absorptance exerted little effect

on energy requirements. Glazing temperatures, however, were higher for

the high absorptance glass

5.10 LIGHTING POWER DENSITY

In addition to the previously described simulations with a lighting

power density of 2 w/ft^ (21.5 w/m^) , values of 1 and 3 w/ft^ (10.8 and

32.3 w/m^) were simulated, while holding illumination level constant.

This corresponds to varying lighting system luminous efficacy.

Simulations were executed for the 30 and 90 percent glazing areas and

the 0.8 glazing transmittance, for all geographical locations. The

impact of lighting power density on heating, cooling, lighting and

total energies, and peak loads, was evaluated.

Figures 27a through 27c present the results for Los Angeles. As shown

in figure 27a total energy reductions are greatest for the highest

lighting power density, and decrease with decreasing lighting power

density. In addition, the slope of the total energy ratio within the

glazing area ratio range of 0.3 to 0.9 is clearly negative for the

highest lighting power density, nearly flat at the middle lighting

power density, and positive for the lowest lighting power density.

These effects are due to the relatively greater benefits of daylight

for the least efficient lighting system (highest lighting power

density) . More energy savings are possible through the substitution of

daylight for the inefficient electric lighting compared to the most

efficient lighting system. The largest glazing area is most effective

for the least efficient lighting system, even though some daylight

saturation occurs, since small lighting energy reductions and

21
associated cooling energy savings have a relatively large effect on

total energy usage. Conversely, with the lowest lighting power density

the 30 percent glazing area is most effective, since reductions in

lighting energy are less important. (The heating, cooling and lighting

energy ratios are shown in figure 27b, and peak heating and cooling

loads in figure 27c.) Reductions in lighting energy are similar,

although somewhat less for the lowest lighting power density. The

heating energy plots indicate reductions for the lowest lighting power

density compared to heating energy increases for the highest lighting

power density. This trend is, however, reversed for cooling, with

large increases for the lowest lighting power density. This is due to

the fact that, relatively speaking, the lighting power is not as great

a contributor to the cooling load, so that higher solar gains with

larger glazing areas had a greater effect. Regarding peak loads, peak

heating load was unaffected by lighting power density, while peak

cooling loads ratios varied inversely with lighting power density.

Results were generally similar for other locations. For example.

Figures 29a through 29c are for El Paso. Total energy ratios are least

for the highest lighting power density. Lighting and heating energies

are not strongly affected by lighting power density, however, cooling

energy ratio is noticeably higher for the lowest lighting power

density. Peak cooling loads ratios vary inversely with lighting power

density, while peak heating loads are unaffected. Figures 28a through

28c, 30a through 30c, 31a through 31c, 32a through 31c, 33a through

33c, and 34a through 34c present similar results for Lake Charles,

Nashville, Seattle, New York, Omaha and Madison, respectively. The

effect of' lighting power density on the slopes and magnitude of the

various energy ratio plots is not strongly affected by geographical

location.

22
6 . CONCLUSIONS

Several general conclusions can be drawn from the detailed simulation

results. These conclusions are strictly applicable only to atrium

buildings which are similar to the simulated buildings.

o The utilization of daylight produced most of the energy savings, due

to reductions in lighting energy to as little as 60 percent of full

lighting energy. The magnitude of the lighting energy savings did

not vary significantly with geographical location.

o The highest glazing transmittance usually yielded the maximum

reductions in total energy usage, due to the large decreases in

lighting energy requirements. However, the high glazing

transmittance also produced higher cooling energies and peak cooling

loads, especially for large glazing areas.

o Total energy requirements were not particularly sensitive to glazing

area, within the range of 30 to 90 percent of atrium roof surface.

This indicates that lighting energy reductions were approximately

offset by heating and cooling energy increases with increasing

glazing area.

o Slight reductions in cooling energy requirements were observed for

the 30 and 60 percent glazing areas, particularly for the cooler

climates

o Peak heating loads did not vary significantly with fenestration

design, due to their dependence on other unrelated factors.

o Heat storage during cool, sunny days with cold nights was effective

at reducing heating, cooling and total energy requirements, although

by a small amount. More sophisticated heat storage procedures have

the potential for greater savings.

o The solar shading strategy used for these simulations was not

effective at reducing total energy usage, due to reductions in

lighting energy savings which offset cooling energy savings. Other

shading strategies hold more potential, and should be evaluated.

Peak cooling loads were, however, reduced considerably.

o Single-pane glazing was found to be more effective than double-pane

for Los Angeles only.

23
o The magnitude of the total energy reduction ratio varied inversely

with the ratio of heating to cooling energy requirements. Thus, the

largest percentage energy reductions occurred for Los Angeles (20

percent) and the smallest for Madison (4 percent). However, total

energy usage for Madison was nearly two and one half times that for

Los Angeles, so the differences in the absolute values of the energy

savings are not as great. The smaller percent total energy savings

at the colder locations can be attributed to larger increases in

heating energy requirements

.

o Since total energy usage remained fairly constant for glazing area

ratios of 30 to 90 percent, but peak cooling loads were greatest for

the 90 percent area, the 30 or 60 percent glazing areas may be the

best choices with high transmittance glazing. The transmittance of

0.5 performed almost as well as the 0.8 transmittance as total

energy usage was concerned, but produced lower cooling energy and

peak cooling loads at the expense of higher lighting energy

requirements. If peak cooling loads or cooling energy usage are

limitations, the moderate transmittance may be the appropriate

choice

.

24
7

REFERENCES 1.

Treado, S., Gillette, G. , and Kusuda, T. , "Evaluation of the

Daylighting and Energy Performance of Windows , Skylights and

Clerestories." NBSIR 83-2726, National Bureau of Standards,

Gaithersburg, MD, June 1983.

2.

Treado, S., Holland, D. , and Remmert, W. , "Daylighting and Energy

Evaluation of Industrial Buildings." NBSIR 85-3241, National Bureau of

Standards, Gaithersburg, MD, February 1986.

3.

Norford, L. , "An Analysis of Energy Use in Office Buildings: The

Case of Enerplex." Princeton University, Center for Energy and

Environmental Studies, Report No. 158, January 1984.

4.

Boggarm, S.V. and Setty, P.E., "Atriums: The HVAC Factor." ASHRAE

Journal, July 1983.

5.Schutrum, L.F. and Ozfsik, N. , "Solar Heat Gains Through Domed

Skylights." ASHRAE Journal, August 1971.

6.

Leung, et. al., "Thermally- Induced Ventilation Applications in

Atria: A State of the Art Report." Eureka Labs, DoE/SF/1154-T3

,

October 1981.

7.

Hunn, B.D. and Peterson, J.L., "Use of an Atrium for the Passive

Solar Retrofit of an Office Building Design and Installation

Experience’." Los Alamos National Lab, LA-UR-82-2040

8.

Ueland, M. , "Solar Atrium: A Hybrid Solar Heating and Cooling

System. " DoE/EG/34135-1

9.

Peterson, J. and Hunn, B. , "Design of an Atrium for a Passive Solar

Retrofit of an Office Building." Los Alamos Laboratory, LA-UR-80-1080

10.

Walton, G. , "Thermal Analysis Research Program Reference Manual."

NBSIR 83-2655, National Bureau of Standards, Gaithersburg, MD, March

1983.

11.

CEL-1 Lighting Computer Program - User's Guide, CR 81,026, Naval

Civil Engineering Laboratory, Port Hueneme, CA, September 1981.

12.

Treado, S., Francisco, C., and Holland, D. , "CEL-1 User's Guide

Update." NBSIR 84-2974, National Bureau of Standards, Gaithersburg,

MD, November 1984.

13. Cathey, H.M. , Campbell, L.E.

,

and Thimijan R. , "The Basics of Light

Rays," U.S. National Arboretiim, U.S. Department of Agriculture,

February 1984.

25
14 . Cathey , H.M. , Campbell, L.E. , and Thimijan, R. , "Comparative

Development of 11 Plants Grown Under Various Fluorescent Lamps and

Different Durations of Irradiation." J. Amer. Soc . of Hort Sci

103(b): 781-791, 1978.7

26
6/5/84 HUGHES JUSTICE COMPLEX

1400 TRENTON. NJ.

Figure 1. Temperature variations in building A atrium

(Hughes Justice Complex)

27

DEG. C
ENERPLEX NORTH AND SOUTH

PRINCETON. NJ.

Figure 2. Temperature variations in buildings B and C

(Enerplex North and South)

28

DEG. C
DEG. FAHRENHEIT

29
TIME (HOUR)

10 11 12 13 H 15 16 17 18 19 20

TIME (HOUR)

Figure 4. Hourly irradiance and illuminance levels in

building D (AT&T Long Lines)

30

S

SCALE

(WM’’
Atrium

All dimensions in feet

loT

l— II 18 II 1

II 19 11 1 * r II u_

1- 150 ^

Figure 5 Linear atrium building
All dimensions in feet

J3X) , aOw, TO^

i

1' II II 1

II % II 1 * L II II 1

Figure 6. Square atrium building

32
PROPORTIONATE

ENERGY

O

oiiyy A0y3N3 lyioi

33

Figure

7a.

Total

energy

ratio

for

transmittance

of

linear

atrium
PROPORTIONATE

ENERGY

O

oiiuy x0y3N3 lyioi

34

Figure

7b.

Total

energy

ratio

for

transmittanlinear

atrium
PROPORT

I

ONRTE

ENERGY

O

LINERR

RTRIUM

r—7- .^ \y

TR-.2 -

Li.. *

> /\

r? . \ / / «.r LL J

'

ra

=

MRDI50N

O

-

OMRHR

A

=

NEW

YORK

+

-

SERTTLE

X

=

NRSHVILLE

o

-

EL

PRSO

V

=

LRKE

CHRRLES

a

-

LOS

RNGELES

12

ap 1I 1I 1I n 0*1 6’0 8*0 Z*0 9*0 S'O VO

oiiyy Y0y3N3 nuioi

35

0.3

0.4

0.5

0.6

0.7

0.8

0.9

GLfiZING

RRER

RRTIO
PROPORT

I

ONATE

ENERGY

O

oiiyy x0y3N3 lyioi

GOO

36

Figure

8a.

Total

energy

ratio

for

transmittance

of

square

atrium
PROPORTIONATE

ENERGY

d

• Oliyy A9y3N3 lUlOI

IT) o

37

Figure

8b.

Total

energy

ratio

for

transmittance

of

square

atrium
PROPORT

I

ONRTE

ENERGY

O

oiiyy A0y3N3 luioi

<NO

38

Figure

8c.

Total

energy

ratio

for

transmittance

of

square

atrium
PROPORT I

ONniE

ENERGY

LI

NEAR

"OTRIUM Q

CJ\QQ

39

Total

energy

ratio

with

solar

shatling,

heat s(

t)Ia

t*a

II (Ii1

1

t:

pane, 1in

i;ar

atri

um
PROPORT

lONRTE

ENERGY

SOUfiRERTRIUM

oiiyy A0y3N3 luioi

CO0) -C

oOc

•fH •o

CO X

(/]

CO —

(

o

(0

4J

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5-1 C

(U CO c

<U IV

QiO

CQ

CO )-i u o

o u H UJ

o

3

40

single

pane,

square

atrium
41

Figure

10a.

Total

energy

versus

glazing

area

and

transmittance,

Los

Angeles,

linear

atrium
O

COo (T

ct: ccLJ

CC

CD od

oiiyy x0y3N3 %

U3 CO D <U

(0 »H U d) (U O' > c<

>1

u> CO Ui O

0) ^ c

(U

d> O' o c c

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•H E

rH COc

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<0 4J

CCS 0> O' C C H

*H CO 4J N (1)

CCS CCS C

Q) rH 'rH as CT»rH noou3

O'

•iH tu

42
J o

(Do O

H—

hcc

ccUJ

or

ccCD oo

43

Figure

10c»

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance,

Los

Angeles,

linear

atrium
LINEAR

ATRIUM

GLAZING

AREA

RAT 1

0-0.

9

LOS

ANGELES,

CA

HEATING

fTi

0001.

TNG ^

f.IGHTING

H

TOTAL

n

EXj/nig>i 'u3!du yooij/x9y3N3

44

Figure

lOd.

Energy

usage

versus

glazing

transmittance

Los

Angeles,

linear

atrium
LINEAR

ATRIUM

cnCJ

CO

LJ

-j

UJ

CD

CC

COO

sij/niGM 'u3yu yooij/A9y3N3

45

Figure

lOe.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Los

Angeles,

linear

atrium
cno

ID

0 o

ha:

ccLJ

0:1 azCD

o

o

OIIUM A0y3N3 1U101

IU}

c

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46
o

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oiiuy A0y3N3

CQ CQ 9 (U (Q iH u <u 0) O' > c<

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47
o

CDo

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t—

I

CE

CT

LaJ CC

C£l

o

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48

Figure

11c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance,

Los

Angeles,

square

atrium
SQUARE

ATRIUM

GLAZING

AREA

RAT 1

0=0.

9

OZ ST 01 S 0

2ij/niG>i 'u3yu yooij/A9y3N3

49

Figure

lid.

Energy

usage

versus

glazing

transmittance

Los

Angeles/

square

atrium
SQUfiRE

ATRIUM

ElJ/nig>l 'U3yu M001J/A8y3N3

o

O'

(0u

0

4J

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50
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51

Figure

12a.

Total

energy

versus

glazing

area

and

transmittance,

Lake

Charles,

linear

atrium
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o

i£>

m o CE

Q:: cnu

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52

Figure

12b.

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance,

Lake

Charles,

linear

atrium
>H

E-h GO LO CN]

CC

E-*

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transmittance.

Lake

Charles
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54
LINEAR

ATRIUM

CE

_I

CO

LJ

_J

0^

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o

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CE

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55

Figure

12e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing.

Lake

Charles,

linear

atrium
oiiuy A0y3N3 1U101

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56
m

o

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o

d

57

Figure

13b.

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance.

Lake

Charles

square

atjrium
>H

h- CO LO OO

-H • • •r-ir-r >

t

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58
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59
SQUARE

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60

Figure

13e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing.

Lake

Charles,

square

atrium
Oliuy X9y3N3 1U101

cno

CDo CC

CE

LJ

CE

CD

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61
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CD od

62

Figure

14b,

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance,

El

Paso,

linear

atrium
h-< OO LD CM O

CO

CC

Q_

_]

LJ

CD CD

a:

LJ

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cn

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63

transmittance,

El

Paso
LINEAR

ATRIUH

GLAZING

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HEATING

ta

Cnni

.

B

tG

' n

GATING

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TATAI.

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64

Figure

14d.

Energy

usage

versus

glazing

transmittance

El

Paso,

linear

atrium
LINEAR

ATRIUM

ElJ/ni9>l 'U3yu y001J/A9U3N3

65

Figure

14e.

Energy

usage

with

solar

shading

r

heat

storage

and

single

pane

glazing,

El

Paso,

linear

atrium
U)

m o

(D

O

f—

'

CC

CC

LJ

ct: CC

CD

M

CC

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68

Figure

15c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance,

El

Paso,

square

atrium
SQUARE

ATRIUM

GLAZING

AREA

RAT I

0=0.

9

HEATING

HgHTTNG

H

TOTAL

n

69

Figure

15d.

Energy

usage

versus

glazing

transmittance

El

Paso,

square

atrium
SQUARE

ATRIUM

70

Figure

15e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

El

Paso,

square

atrium
O)

o

CD

9 O CEor

cnLJ

CE

CD

M

CE

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o

d

Oliuy A9y3N3 1U101

71

Figure

16a.

Total

energy

versus

glazing

area

and

transmittancef

Nashville,

linear

atrium
Oliuy X0y3N3

72

Figure

16b.

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance,

Nashville,,

linear

atrium
cna

CDa a:

ct: crLJ

ct: CE

CD

o

d

oiiuy sayoi

73

Figure

16c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance,

Nashville,

linear

atrium
LINEAR

ATRIUM

GLAZING

AREA

RATI0=0.9

NASHVILLE,

TN

HEATING

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TOTAL n

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74

Nashville,

linear

atrium
LINERR

RTRIUM

Eij/nia>i ‘u3au aoou/;0a3N3

75

Figure

16e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Nashville,

linear

atrium
h-

'

H—

«

CO

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CO

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>-

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1

1

c:?—

357

1

;

•

;

1

1

1

11

1

1

1

;

z:

^ _

1

:z> OH - E— LJ

(T _]

1 ^ ^

\ J ^

1

LJ —

OH >

(T. X X CO

a X

1

1

1»

1» CO X

"

1 1

1

1

11

.r: WW

/ /

i!

t

i

0*1 8* o CD

• 0 V* 0 s* 0 0*0

O)

o

CDo

E—

01

0:1 (T

LJ

OH

crCD

o

d

Oliuy X0y3N3 1U101

76

Figure

17a.

Total

energy

versus

glazing

area

and

transmittance,

Nashville,

square

atrium
C7^ O

d CC

CO

bJ

CE

CD

o

d

OllUy A0y3N3

CO3 ^

77

Figure

17b.

Heating,

cooling

and

lighting

energy

vers

glazing

area

and

transmittance,

Nashville

square

atrium
O)

o

CDo

E—

cr

CE

LJ

or

(H

CD

o

CD

oiiuy SQU01

78

Figure

17c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance,

Nashville,

square

atrium
SQUARE

ATRIUM

GLAZING

AREA

RATIO-0.9

NASHVILLE,

TN

HEATING

V7i

mm.

IMG

ijl

GATING

H

TATAI.

n

CO

o

79

Figure

17d.

Energy

usage

versus

glazing

transmittance

Nashville,

square

atrium
SQUARE

ATRIUM

30

Figure

17e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Nashville,

square

atrium
>H

h- oo LD OO

CO

CO

U1

cc

ct: f—

CD

orLJZ

LJ

LJ

t—

QCO

Q_O

Q_

I

ZD az ort—

01 LJ

0^(r

LJ crLJ

ui

1

1

1

LJ

1 )

1

1

:

i1

11

f

1 VV y’S/TS

//

1

//

(ji o

CD (—4

° £0^

crLJ

0^ ccCD

o

o

Icnc

(T5 u

4Jc

<TS

(Q s

<D 3

S-i -H

(TJ S-i 01 <T3 C

•HN (T3 (C <D iH C

Oi**^

cn3 "

U3 <V U 1—1 0^ 4J > -p

(T3 >1 a; dicd

c

(U uc

(—I (0

<Q -p ® 'd

Eh S

(T3 00

<Vu3

Di •H

O’l 9*0 9*0 VO 2*0 0*0

oiiyy A0y3N3 luioi

81
OllUy A8y3N3

82

0.0

0.3

0.6

0.9

GLRZING

flRER

RRTIO
E— OD LD rs]

cnCO

CD

cn

orE—

cnQ

cno

LJ

E—

O

a.oct: CL

CL E-h cn e-h LJ cn 2 LJ

^ cn

-j

CD CD

^ E-^ ^

cr 0= CD

LJLJO

x: o

H II <

n r—

LJ

i

1

1

1

t

1

1

1

\

lli l:

j

\

\

«

\

\

' Um rhfi 1 LLIC T » hi

j

\ 1

\1

\

1 ,

1

1

1\

t

• j

cna

CD

t o

E'- enCL

cnLJ

tL

cnCD

o

CD 2*1 0*1 8*0 9*0 i^*0 2*0 0*0

oiiuy SQU 01

cnc

N

<0 rH

cr»

03s

CQu

0)>

0} no

<0O

01c

•H

iH

o

o

0

'Oc

(001c

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4J

(0

<u jC

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0) cu

o

00

(U

Ul3

01 •H

b4

4J 73 fO c

<0

<0 <u

<v c

U °H

<0 *H

83

transmittance,

Seattle
LINEfiR

ATRIUM

GLAZING

AREA

RAT 1

0-0.

9

SERTTLE

NR

HEATING

E3

nOOLINOra

'

LIGHTINGS

TOTAL

n

ElJ/ni9>l 'U39U y001J/X9y3N3

84

Figure

18d.

Energy

usage

versus

glazing

transmittance

Seattle,

linear

atrium
LINEAR

ATRIUM

2ij/nig>i "ugyu yoou/A9y3N3

85

Figure

18e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Seattle,

linear

atrium
Uim o

COo

E—

a:

CE

LJ

CE

CD o

CD ICQC

(0uT3C

<tj

iQ s

<D 3 u -H

(Q

U

O' <0 c

•H 0 N U

<0 <T3

r-»

C7> O’

U)

in3 ^ • CO <u

)-4 rH

<D 4-» > 4-> (0 >1 o

CT»C0 U0) - C 0) <D oc

rH (CJ (0 -U

4J 4J O -H ^ E

<TJ ou3

CP •H

EL4

86
05O

CDO

h-* cr

crLJ

CE

CD

o

d

Oliuy

Figure

19b.

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance,

Seattle,

square

atrium
E-i OO LO OO•

CD

CO

COZ

CEorE—

CO

CD

01O

LJ

3CT3

QC

f—

01 LJ

gLJE- ^ E— ^ 01 cr ^3LJ

gocn o

0^

Q_

CD CD

UL^J tI1I1111 1 1\111111 t

i|11I ' \111«1111I1

rim U 1) 11

<J) o

CDo

E—

cr01

CE

LJ

01

CE

CDM

CE

_J

CD

ro9 Ooo

0*1 8*0 9*0 V*0

oiiuy SQuon

Z'O 0*0

O'c

•HN

(13 rH

U>

CO3

CO ‘ u

a;> *• (U

CO 4J

(d 4J O (0 iH 0) CO

CJt c -

•H 0) ^ o o c O (t3 O 4J c s

as COc £

CT» <0 3 C u •H

•H 4J

4J 4J

as 'D (d 0) c

s: (0

U

as (d as <y 3

0) ui CJ* CU (0 CO O

o>

0)u3

O' •H

88
SQURRE

RTRIUM

GLRZING

RRER

RRTIO-0.9

OOo

LHO

CNJ o

LJ

CJ

cc

CD

:z

cc

cc: h89

Figure

19d.

Energy

usage

versus

glazing

transmittance

Seattle,

square

atrium
SQURRE

ATRIUM

90

Figure

19e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Seattle,

square

atrium
C7) O

IDO

d

o

d

O

t—

E—

cn

cc: orLJ

CE

CD

M

crCD

oiiuy A0y3N3 1U101

I0] c:

(0u

4Jc

«3 s

(0 3

0) 'H u u

(0 4J

CO

cr» c

•H <0 N 0) CO C

rH *H

01 •• 3 ^

01 U

u O

<D >i >

>1 (1) cnZ

u

01 - C 0)

01 u

c

iH cO

CO 4J

4J 4J O -H

Eh S

CO 0

CN

01u

3

cr> •H

Eu

91
OllUy A9y3N3

CO3

COU X

<u u

> o

ao 3

s-i <u (U z

C C 1-1 •fH CTJ UNO;

CO CQ c

<X) X aO ^

XO

CN

<U

1-4 3

bO

[X,

92

GLAZING

AREA

RATIO
E-iI OO LO OO

• • • >H—H 1 ^ i ^ 1 S

' CE i

! H-i :

CO

a

O ^

-J 2 ^

LJ £ ^ ^ P ^

CE

^

2 O

y 3

q:: ;± LJ

o ^ ^

CL —

O

QCD CD

1—4 t—

^ E-I _]

a: CE o

LjtjJO

Q_

II N <1

2*

r—r-vr-T cn

• Lu |_ji T »

\

\

1\1

1

1

J o

O

CO E—

; 1 n1

L. “ o 5-

CL

CE

LiJ CL

(E

CD

1 M

(E

CD

to

•

i

11\

1t

\

\

1

1)

\

C

1

’ T B . J " o

o

_ o

1 0 *l 8* o CO

• 0 o CM• 0 0*0

oiiuy sauoi

93

Figure

20c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance.

New

York,

linear

atrium
LINEAR

ATRIUM

GLAZING

AREA

RATI0=0.9

NEN

YORK,

NY

HEATING

fTi

0001.

TNG ^

LIGHTING

m

TOTAL

n

94

Figure

20d.

Energy

usage

versus

glazing

transmittance

New

York,

linear

atrium
LINEAR

ATRIUH

95

Figure

20e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing.

New

York,

linear

atrium
Oliuy A0y3N3 3U101

CDO

COo

E-^ cn

Csl crUJ

or

cnCD

o

CD

Icac

rtj u

c

s

(Q 3

0) ’H U U

(Q 4J

<0 cnC 0) •H U

N (T3 (0 3

pH cr

CD W

CQ » 3 ^

CQ U

H O

<U >• >

>1 0> a>2

u

0) - C Q)

<v o

c

rH (0

(C3 4J

4J 4J

O -H

Eh S

(0 r—

I

CN

<Du

3

CD •Hb4

96
05O

(O

o

h-

cr

ct: ccu

Q:: CE

CD

o

d

OllUd A0y3N3

97

Figure

21b.

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance.

New

York,

square

atrium
>-• M oo in CM

CD CD

V/ E-h _J

azdicD ljLJO

Ql. X CD

II II <

O)

• LJ

j

t

t

1%

1

1

1

4

" o

Ok—

H

CD (—

1

1t 1

i|

1

t

1

t 1 t

1a

1

i

1 rt 1

.

1

1

1

1

” o 9-

ct: X

LJ

(XX

CDX1——

•

M

X

_]

CD

ro

•

(

»

1

1t

1

1

1

1

n 1

1 “ o

o

_ o

0*1 8‘0 9*0 VO 2*0 ' 0*0

oiiuy SQU01

93

Figure

21c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance.

New

York,

square

atrium
SQUARE

ATRIUM

GLAZING

AREA

RAT 1

0=0.

9

99

Figure

21d.

Energy

usage

versus

glazing

transmittance

New

York,

square

atrium
SQUARE

ATRIUM

100

Figure

21e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing.

New

York,

square

atrium
8-^ 00 LO (M

CD

0^

lj£

ct:

LiJ

cr

E—

o

Q_o

0^

CL

cr cr

LJ n

'Z o

r

O)

c.

1 “ o’

O

CD E—

1

(

1

r Vj»» CL

crLJ

CL

crCD

•—

M

crCD

ro

•

1

'

1

YUAIS

'

1

1

0.0

0

i!

il

0* 1 8- 0

9‘ 0 02* 0 0*0

oiiuy x 0y3N 3 1U101

101

Figure

22a

«

Total

energy

versus

glazing

area

and

transmittance,

Omaha,

linear

atrium
h- GO LD CM

o

CO

cn

CO

2: cc

CD

0^

LxJ LJ

LJ Or: LJ

gO^ X XXX r LJX

X —

'

oX

X

CD

CD CD X XX —

1 — — h-» cr ^ —1 ni

E— X O CD qLiJO —

E-. X CJ _1

II II H < X

2*1 0*1 8*0 9“0 VO 2*0 0*0

oiiyy A8y3N3

102

Figure

22b,

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance,

Omaha,

linear

atrium
>H

E-h OD LO CsJ

CO

CO

CO

CC

E—

COQ

cro

LJ

(T.

E—

Or: o

CL

o

CL

I—• LJ

QC 2

E—

cr

cr QC X X X

LJX o

CD CD

^ E—

cr ^ o

LJLJO

CL =1=

I y <

r—r-\^rr-\ LJ Lj*UJ T '

\ 1

1\

1\

t

t

\

1 U; 1 t

1 \\

1

1

1

\ 1 \

1

1%

\

\

1

1

\

\

11

t

tX

\ uu

(D

m o

(D

O XX

X

LJX

X

CD

o

d

2*1 O’l 8-0 9‘0 ^'0 Z'O 0*0

oiiuy SQU01

103

Figure

22c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance,

Omaha,

linear

atrium
LINERR

RTRIUH

GLRZING

RRER

RRTI0=0.9

OMRHfl,

NE

HERTING

GRni.TNG

'f

lGHTING

H

TRTRI.

n

104

Figure

22d.

Energy

usage

versus

glazing

transmittance

Omaha,

linear

atrium
LINEAR

ATRIUH

105

Figure

22e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Omaha,

linear

atrium
E-1 GO LO OO

• • •

I

^

LJ

(E -s 01

LJ X

ct: ac X X X o

a

CD

U)

• ^

1 « o

•

O

CD (—•

1

1

\ " O 5-X

X

LJX

X

CDX

M

X

CD

ro

•

1

1

1

1

1s

L AJL

r, i

J

1

1

0.0

0

i!

il

O’l 8'0 9*0 VO 0*0 0*0

oiiuy A 0 y 3 N 3 1U101

106

Figure

23a,

Total

energy

versus

glazing

area

and

transmittance,

Omaha,

square

atrium
(J) o

CDo OH-H CE

CE

LJ

ct: (E

CD

CDd

oiiuy

(QSuuo> - >uC

(0 u E

<y oc

a; *• 0)o c c

•H (0

4-» 4J JS ^

D^*H

•H £

•H toC

«3 C ^

(0 4J C C

•H (0 *H E O «3 3 O 0> -H o u u

(0 4J

*• <C

CJ» C7» c c o; •H >H U

4J

N (Q (0 (Q 3

0) fH CT S 03 m

CN

03U3

CT» •H

CX4

107
PERK

PROPORTIONATE

LORDS

HEATING

SQUARE

ATRIUM

COOLING

OMAHA,

NE

E-. OO LO CM

cn

CD

CO

CE

—inw

O)

•

1

I

1I

11

1

" o

O8—8 CO ^

1 . 1 1 \

,

1t

11

1

1

«

1 1 %

811

1

1 Hti' 1

1

1

1

1

1t

1

1

1 o 5-

CE

CE

LJ

tr

CE

CD

M

(E

_J

CD

ro

• 9

1

1\

1

11

1

1

1

11

1

1

n n u 11 1

0.0

0

0*1 8* o CD O o CM

• 0 0*0

oiiuy SQU01

108

Figure

23c.

Peak

heating

and

cooling

loads

versus

glazing

area

and

transmittance,

Omaha,

square

atrium
SQURRE

RTRIUH

GLRZING

RRER

RRTIO-0.9

QMRHR,

NE

HERTING

El

COOLING

E

'

LIGHTING

B

TOTRL

109

Figure

23d.

Energy

usage

versus

glazing

transmittance

Omaha,

square

atrium
SQURRE

RTRIUM LJ

CEXX

X

o

2 ij/nig>i "ugyu yoou/A0y3N3

110

Figure

23e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Omaha,

square

atrium
>-

E-i OO LO CM

CO

CO

CO

CC

OH

CD

cc: 2: §

LaJ E—

CT

g or CO ^ cz »—

S S E

Q_ —

O

Q::

Q_

"TPi OT

C A

1

1

1

1

11

1

0

0

CO 4

1 ;

1

1t

11

1

1

r>

1 !

C,' op

1

1

1

1

1

1

1

” 0 ^

(T

LJ

QC

CC

CD

M

CE

CD

ro

1 111

1

1

1

1

1

1 1

1

1

1

1

11 •-xk V?1

1

1

0.0

0

1.

« 0 GO 0 9* 0 0 (M 0 0*0

Oliuy A9y3N3 1U101

Hi

Figure

24a.

Total.

energy

versus

glazing

area

and

transmittance/

Madison/

linear

atrium
i

O)

o

CD

CD

E-h CE

cr

CE

LJ

0:1 CE

CD

M

(E

_J

CD

O

CD

Oliuy A0y3N3

112

Figure

24b.

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance,

Madison,

linear

atrium
E— OO LD OO

CD

CD

CD

cr

I

•v o

CD

I—

Q

cr

CD CD

-J ^ cr o

LJUO

Q. X CD

I I <

P" m L1 LJ liL

\ \\

\

\ \\

li,

\1

\ i \

\

\\

\

I

I

1

1

1

1

1

1 r

1 ,

1 TJ

1 il

05a

CDo

E—

cr

Q:: crLJ

Q::

a:

CD

o

d

Z'\ 0‘1 8’0 9*0 ^^*0 2*0 0*0

OllUd SQU01

O'c

•HN

(0o»

03D

03U

03 73

<0O

o>c

o

ou

'Uc

«T3 cnc

4J -U

IT3 73

(D C

.C

<T3 ^ 73 05

73 0) C

0) U >iH

(li 73

U

CN0) u

3

U>

•H

Eb

113

transmittance,

Madison
LINEAR

ATRIUM

GLAZING

AREA

RAT 1

0=0.

9

114

Figure

24d.

Energy

usage

versus

glazing

transmittance

Madison,

linear

atrium
LINEAR

ATRIUM

Eij/nia>i 'u3au aoou/A9a3N3

115

Figure

24e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Madison,

linear

atrium
o

O

CDO CC

0^

CE

LJ

CE

CD

o

o

Ollbfy X9y3N3 3U101

116

Figure

25a.

Total

energy

versus

glazing

area

arid

transmittance,

Madison,

square

atrium
(T) O

CDO

E—

(T

crLJ

CE

CD

o

d

oiiuy x0y3N3

117

Figure

25b.

Heating,

cooling

and

lighting

energy

versus

glazing

area

and

transmittance,

Madison,

square

atrium
[moo \r>c4

CO

CO

CO

z

0=

ct:

cn

LiJ t—

cr

E—

oro

Q_o0:: Q.

0^

h-

'

cr ^

o

LJ CO

rv^ I—

I

CC Q

=)cr o ^

cn

CD CD

^ l--« J CE 0= O

ljLJO

CL CJ

II II <

JUS 1 1 1

I 111

1

1

1 1

1 8

*

1 fl

1 1

1

«

1«

1

« 1 «

1

1

1(

1

1 (

1

I

1(

1

11

1

1\

1

11

1

11

1

1

11%

1

(

1

ri n

Ui

(J) o

m o CE

CE

CE

LJ

q:

(E

CD

M

CE

_)

CD

roo

o

o

0*1 8*0 9*0 VO

oiiuy SQU01

2*0 0*0

118

Figure

25c.

Peak

heating

and

cooling

loads

versus

gl,azing

area

and

transmittance/

Madison,

square

atrium
SQUARE

ATRIUM

GLAZING

AREA

RAT I

0=0.

9

119

Figure

25d.

Energy

usage

versus

glazing

transmittance

Madison,

square

atrium
SOURRE

ATRIUM o

CO

I—

t

Q

CC

2 ij/nia>i 'uaau yoou/A0a3N3

120

Figure

25e.

Energy

usage

with

solar

shading,

heat

storage

and

single

pane

glazing,

Madison,

square

atrium
LINEAR

RTRIUH

TRRNSMlSSIVITY-0.2

LOS

RNGELES,

CR

HEATING

B

COOLING

H

LIGHTING

B

TOTRL

121

Figure

26a.

Energy

usage

versus

glazing

absorptance

linear

atrium,

Los

Angeles
LINEAR

ATRIUM

TRANSMISSIVITY-0.2

LAKE

CHARLES,

LA

HEATING

B

COOLING

H

1

1

GATING

B

TOTAL

122

Figure

26b.

Energy

usage

versus

glazing

absorptance

linear

atrium.

Lake

Charles
LINEAR

ATRIUM

TRANSMI5SIVITY-0.2 EL

PASO,

TX

HEATING

0

COOLING

S

'

LIGHTING

9

TOTAL

123

Figure

26c.

Energy

usage

versus

glazing

absorptance

linear

atrium,

El

Paso
LINEAR

ATRIUH

TRRNSMISSIVITY-0.2 NASHVILLE,

TN

HEATING

B

COOLING

S'

LIGHTING

B

TOTAL

124

Figure

26d.

Energy

usage

versus

glazing

absorptance

linear

atrium,

Nashville
LINEAR

ATRIUM

TRANSMISSIVITY=0.2 SEATTLE,

WA

HEATING

0

COOLING

H

LIGHTING

B

TOTfll

125

Figure

26e.

Energy

usage

versus

glazing

absorptance

linear

atrium/

Seattle
LINEAR

ATRIUM

TRANSMISSIVITY=0.2

NEN

YORK,

NY

HEATING

B

COOLING

B

LIGHTING

B

TOTAL

126

Figure

26f.

Energy

usage

versus

glazing

absorptance

linear

atrium.

New

York
LINERR

RTRIUM

TRflNSMISSIVlTY-0.2 OMAHA,

NE

HEATING

0

COOLING

B

LIGHTING

B

TOTAL

CD

^

[\ o o

CJ) ro

• • o o

o

c

<0 4JCuuo

Ui

fO

CT> c

•HN

(0 rH

CJ»

in3

inu

(1) >

0P> <0

in3

>1

O'u

<DC

a

VO

CN

2 Ck^ CO

OS Sl^ OV S£ 0£ S2 02 SI 01 S 0:=) CL CD

Eij/nig>i yoou/A0y3N3

127

linear

atrium,

Omaha
LINERR

ATRIUM

TRflNSMISSIVITY=0.2 MADISON,

WI

HEATING

B

COOLING

H

LIGHTING

B

TOTAL

128

Figure

26h.

Energy

usage

versus

glazing

absorptance

linear

atrium,

Madison
C7) O

CDO (T

a:: ccLJ

ct: (H

CD

o

o

oiiyy A9y3N3 luioi

129

Figure

27a,

Total

energy

ratio

vs

lighting

power

density

Los

Angeles
cna

O

(O

o

E—

CE

ct: CE

LJ

Ct: (E

CD

o

d

oiiuy

130

Figure

27b.

Heating,

cooling

and

lighting

energy

vs

lighting

power

density,

Los

Angeles
PROPORT

I

ONniE

LOADS

,

pn

PERK

LINEAR

ATRIUM

,

A

=

HEATING

LOS

ANGELES,

OR

-i

nCOOLING

TRANSMISSIVITY-

.8

3 m 1—1

1—

cn

11

1

%

\

1

1\

LlI I4J

1 T

1

If

1

1

.6

0

mo

ing

loads

vs

lightin

geles

\

\ 1 1 It

it

• ' 1 i

• ‘ 1 It

1

1

.3

0

GLRZING

RRER

RF

lak

heating

and

cool:

iwer

density^

Los

An(

•

' 1 iV

1 j

li

1

i

hi T 1

1

1\

1

\

1t

jiyj

1

1

1

0.0

0

Figure

27

c.

Pe po

1

\%

11

1

1

1

i

1

1

1

1

1

»

1

2*1 0*1 8*0 9*0 V

*0 2*0 0*0

oiiuy SQU01

131

Figure

27

c.

Peak

heating

and

cooling

loads

vs

lighting

power

density^

Los

Angeles
132

Figure

28a,

Total

energy

ratio

vs

lighting

power

density

Lake

Charles
oiiyy x0d3N3

133

Figure

28b.

Heating,

cooling

and

lighting

energy

vs

lighting

power

density.

Lake

Charles
OllUd SQUOI

134

Figure

28c.

Peak

heating

and

cooling

loads

vs

lighting

power

density,

Lake

Charles
CT) O

O

£—

CE

ct:: (T

LJ

ct: (T

CD

o

d

OllUy A9y3N3 1U101

135

Figure

29a.

Total

energy

ratio

vs

lighting

power

density

El

Paso
O)

a

O

CD (—

t

(=; (T

CT

LJ

ct: (T

CD

o

d

oiiuy ;^0y3N3

136

Figure

29b.

Heating,

cooling

and

lighting

energy

vs

lighting

power

density,

El

Paso
o

CDo

t—

ac

Q:: ccLJ

ct: crCD

M

a:

CD

o

d

oiiuy sauoi

137

Figure

29c.

Peak

heating

and

cooling

loads

vs

lighting

power

density,

El

Paso
CDO

COo

h-* cror

CE

LJ

or

CE

CD

o

o

Oliuy A0M3N3 lyioi

138

Figure

30a.

Total

energy

ratio

vs

lighting

power

density

Nashville
(T>

Q O

COo

E-^ CCcr

CE

LJ

ct: CE

CD

o

o

oiiuy i0y3N3

139

Figure

30b.

Heating,

cooling

and

lighting

energy

vs

lighting

power

density,

Nashville
O

COd

O

cr

ct: crLJ

q:

crCD

M

cr_j

CD

rod

o

d

oiiyy sayoi

140

Figure

30c.

Peak

heating

and

cooling

loads

vs

lighting

power

density,

Nashville
oiiyy A0y3N3 lyioi

cno

IDO CC

ct: CE

LJ

(H

CE

CD

o

o

141

Figure

31a.

Total

energy

ratio

vs

lighting

power

density

Seattle
O)

o

O

CD CE

CC

LJ

or

CT

CD

o

d

oiiyy ;^0y3N3

142

Figure

31b.

Heating,

cooling

and

lighting

energy

vs

lighting

power

density,

Seattle
CDO

COo

h-< 0=or

CC

LJ

ct: CE

CD

o

CD oiiyy SQU01

143

Figure

31c.

Peak

heating

and

cooling

loads

vs

lighting

power

density^

Seattle
oiiyy ;9y3N3 nyioi

144

0.0

0.3

0.6

0.9

GLAZING

AREA

RATIO
cno

COo

E-< CE

CE

LJ

(E

CD

M

CE

_J

CD

a

d

Oliuy ;^0M3N3

145

Figure

32b.

Heating,

cooling

and

lighting

energy

vs

lighting

power

density.

New

York
PROPORTIONATE

LOADS

,

pn

PEAK

LINEAR

ATRIUM

,

A

-

HEATING

new

YORK,

NY

2

“COOLING

TRANSMISSIVITY=.8

3 (—

1

n rvi

C7^

•

11

1

1

11

1

S 1

"0

0

U CD ^

n

"0 3-

ct: CE

LJ

or

crCD

M

crCD

m

•

.

11

; I % . 1

1

1

1t UJI! r^c i

11

1

11

1

1

1 . J

1

1

0.0

0

Z^\ 0*1 8‘0 9*0 KO 0‘0

Oliuy SQU01

146

Figure

32c,

Peak

heating

and

cooling

loads

vs

lighting

power

density.

New

York
(7) O

CDO CE

cc: CE

LJ

cl: CE

CD

o

d

147

Figure

33a.

Total

energy

ratio

vs

lighting

power

density

Omaha
cno

(D

O

O•—

I

E—

CE

Ce: crLJ

q:

CE

CD

M

CE

_J

CD

o

o

OllUy A0y3N3

148

Figure

33b.

Heating,

cooling

and

lighting

energy

vs

lighting

power

density,

Omaha
o

(D

O

E—

cr

Q:: CE

LJ

crCD

M

cr-j

CD

o

d

oiiuy sayoi

149

Figure

33c.

Peak

heating

and

cooling

loads

vs

lighting

power

density^

Omaha
G)9 O

CDO

E—

CE

q:

CE

LJ0^ (E

CDM

CE

_J

CD o

CD

150

Figure

34a.

Total

energy

ratio

vs

lighting

power

density

Madison
G)

O

CDO

E—

CC

Cd

crLJ

ccCD

M

cr_J

CD

a

a

Oliuy A0y3N3

151

Figure

34b.

Heating^

cooling

and

lighting

energy

vs

lighting

power

density,

Madison
o

(D

d CC

ct: ccLJ

£t: GZ

CD

o

d

oiiuy soyol

152

Figure

34c.

Peak

heating

and

cooling

loads

vs

lighting

power

density,

Madison
NBS»n4A (REV. 2-ac) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBSIR 87-3594

2. Performing Organ. Report No. 3. Publication Date

SEPTEMBER 1987

4. TITLE AND SUBTITLE

Fenestration Design for Building Atria

5. AUTHOR(S)

S.J. TreadOr D.B. Holland, J.W. Bean, G.L, Gillette

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions)

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9.

SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State, ZIP)

U.S. Department of Energy American Architectural Manufacturers Assoc

1000 Indqiaidence Ave., S.W. 2700 River Road, Suite 118

Washington, D.C. 20585 Pes piaines. IL 60018

10.

SUPPLEMENTARY NOTES

I I Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here)

The influence of fenestration design on building energy performance is evaluated,

based on measurements in four atrium buildings and a series of detailed computer

simulations using TARP and CEL-1. The iirpact of glazing area and solar-optical

properties is examined for a linear and central atrium building for eight geographical

locations. The usefulness of automatic solar shading and heat storage strategies is

also investigated. Guidelines are presented for effective design of atrium

fenestration.

The results indicate that when daylighting is used, appropriate fenestration design

will result in lower building energy requirements than would occur with no

fenestration. Reductions in annual building energy requirements of over 20 percent

were observed, although the total savings potential vari^ with geographical location.

12.

KEY WORDS (S/x to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) Keywords: atrium; building energy; daylighting; glazing; heat storage; solar shading

13.

AVAILABILITY

6T~I Unlimited

I I For Official Distribution. Do Not Release to NTIS

I I Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402.

Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

169

15. Price

$18.95

USCOMM'DC S043-P80
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