Table Of ContentPASSIVE COOLING OF BUILDINGS
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PASSIVE COOLING
OF BUILDINGS
EDITORS
M. SANTAMOURIS AND
D. ASIMAKOPOULOS
from Routledge
from Routledge
First published by James & James (Science Publishers) Ltd. in 1996
This edition published 2013 by Earthscan
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© 1996 James & James (Science Publishers) Ltd
All rights reserved. No part of this book may be reproduced in any form or by any
means electronic or mechanical, including photocopying, recording or by any
information storage and retrieval system without permission in writing from the
publisher
A catalogue record for this book is available from the British Library
ISBN 978-1-873936-47-4 (hbk)
Typeset by Edgerton Publishing Services, Huddersfield, UK
Table of contents
Preface ix
1 Cooling in buildings - C. Ba/aras 1
Historical development I
Buildings and energy consumption for cooling 12
Current technology of air-conditioning systems 18
Current technology for natural ventilation in buildings 26
Conclusions 29
References 30
2 Passive cooling of buildings - A. Dimoudi 35
Benefits of passive cooling 35
Passive cooling strategies 37
Cooling potential-limitations 52
Epilogue 53
References 54
3 The Mediterranean climate - I. Livada-Tselepidaki 56
Geographical characteristics 56
Solar radiation 58
The air temperature 61
Relative humidity 67
Characteristics of the wind 68
Cloudiness 69
Sunshine 72
Meteorological measures to represent environmental stress 73
Cooling degree days 78
Thorn's discomfort index 81
References 81
Additional reading 83
4 Microclimate - A. Dimoudi 84
Climate and microclimate 84
Topography as climate modifier 84
Urban forms as climate modifiers 89
Climate and design requirements 91
References 94
v
vi PASSIVE COOLING OF BUILDINGS
5 Urban design - A. Dimoudi 95
Stages of urban design 95
Building design 112
References 126
6 Thermal comfort - C. Balaras 129
The influencing parameters 129
Psychrometrics 133
Thermal equilibrium of the human body 134
Comfort indices 138
Prediction of thermal comfort 146
References 156
Appendix A 158
Appendix B 166
7 Cooling load of buildings - C. Balaras 171
Factors affecting the cooling load 172
Methods for calculating the cooling load in buildings 175
Calculation of monthly averaged cooling load 176
A simplified manual method for calculating cooling loads 179
References 184
8 Heat attenuation - C. Balaras 185
The role of thermal mass 185
Heat transfer mechanisms 190
Parameters influencing thermal mass effectiveness 192
Calculations of thermal mass effectiveness 196
Case studies 202
References 207
Appendix A 212
AppendixB 212
9 Natural ventilation - E. Dascalaki and M Santamouris 220
Natural ventilation 220
Empirical/simplified methods for estimating ventilation rates in a
single-zone building 236
Natural convection heat and mass transfer through large internal openings 247
Multizone modelling 261
Night ventilation 266
References 271
Appendix A 275
AppendixB 288
Appendix C 298
Appendix 0 301
URBAN DESIGN vii
10 Solar control-A. Dimoudi and D. Mantas 307
Description of solar geometry 307
Prediction of sun's position 309
Graphical design tools 312
Solar control review 328
Solar control issues 329
Solar control techniques 330
References 343
Further reading 345
Appendix A 345
Appendix B 355
11 Ground cooling - A. Argiriou 360
Ground cooling by direct contact 360
Earth-to-air heat exchangers 367
Conclusions 391
References 392
Appendix A 394
AppendixB 401
12 Evaporative cooling - A. Argiriou 404
Physics of evaporative cooling 404
Evaporative cooling systems 408
Performance of evaporative cooling devices 415
Conclusions 420
References 421
Appendix 422
13 Radiative cooling - A. Argiriou 424
Physical principles of radiative cooling 424
Radiative cooling systems 432
Modelling the flat-plate radiative cooler 437
Potential of radiative cooling 438
Problems related to radiative cooling 446
Conclusions 447
References 447
Further reading 448
Appendix A 448
Appendix B 452
viii PASSIVE COOLING OF BUILDINGS
14 Simplified methods for passive cooling applications - M Santamouris 455
Cooling requirements of air-conditioned (ale) buildings 455
Cooling requirements of naturally ventilated (n/v) buildings 457
Cooling requirements of buildings equipped with earth-to-air heat exchangers
(buried pipes) 457
Cooling requirements of buildings using night-ventilation techniques 459
Cooling requirements of buildings using night-ventilation techniques and
buried pipes 461
How to calculate the cooling degree hours 463
References 465
Biographies of the authors 466
Index 468
Preface
The increase in household income in Europe and the relatively low cost of electricity
have helped air conditioning to become highly popular. This has resulted in a signifi
cant increase in building energy consumption in southern Europe. Sales of air
conditioning equipment in this region have increased considerably over the past few
years and are now worth close to 1.7 billion ECU per year. In Greece, for example,
while the annual sales of packaged air conditioners was close to 2000 units in 1986,
the market jumped to over 100,000 units in 1988.
The specific energy consumption of buildings for cooling needs is dictated by the
climate, the type of building and the installed equipment. A comparison of the annual
specific energy consumption for cooling in large air-conditioned office buildings in
Denmark, Greece, The Netherlands, Norway, Sweden and the UK, shows a variation
of between 15 to 110 kWhlm2• It should be noted that, despite the Mediterranean
climate, Greek office buildings do not use more electricity than Swedish or British
offices for heating, ventilating and air-conditioning (HVA C) systems during summer.
Clearly, the problem of cooling in buildings is not peculiar to southern climates
alone. It may be just as important in northern climatic regions, depending on the
building type and construction.
The impact of the use of air conditioners on electricity demand is a serious prob
lem for almost all southern European countries. Peak electricity loads force utilities
to build additional power plants in order to satisfy the demand, thus increasing the
average cost of electricity.
Environmental problems associated with the use of ozone-depleting CFC refriger
ants used in conventional air conditioners present an additional argument for mini
mizing the use of HV AC systems for energy savings in the cooling sector. Problems
of indoor air quality associated with the use of air conditioning should also be taken
into account. Recent studies of air-conditioned buildings have shown that illness in
dices are relatively higher for these than those for non-air-conditioned buildings.
Alternative passive cooling techniques, based on improved thermal protection of
the building envelope and on the dissipation of building's thermal load to a lower
temperature heat sink, have been proved to be very effective. These strategies and
techniques have already reached a certain level of acceptance in architectural and
industrial circles. Passive techniques as alternatives to air conditioning can bring im
portant energy, environmental, fmancial, operational and qualitative benefits.
The study and application of passive cooling is a multilayered and multidiscipli
nary process. It is important to treat the subject in conjunction with other aspects of
architectural design; it should not be considered in isolation. A useful framework for
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