ASHRAE 90442-2009 ASHRAE Guide for Buildings in Hot and Humid Climates Expanded with New Content (Second Edition)《该ASHRAE 指南建筑物在炎热和潮湿的气候》.pdf

1、 Front_Matter_10_29_08.indd 1 11/21/08 3:18:15 PMDisclaimerASHRAE has compiled this publication with care, but ASHRAE has not in-vestigated, and ASHRAE expressly disclaims any duty to investigate, any product, service, process, procedure, design, or the like that may be described herein. The appeara

2、nce of any technical data or editorial material in this publication does not constitute endorsement, warranty, or guaranty by ASHRAE of any product, service, process, procedure, design, or the like. ASHRAE does not warrant that the information in the publication is free of errors, and ASHRAE does no

3、t necessarily agree with any statement or opinion in this publication. The entire risk of the use of any information in this publication is assumed by the user.CopyrightNo part of this book may be reproduced without permission in writing from ASHRAE, except by a reviewer who may quote brief passages

4、 or reproduce il-lustrations in a review with appropriate credit; nor may any part of this book be reproduced, stored in a retrieval system, or transmitted in any way or by any meanselectronic, photocopying, recording, or otherwithout permission in writing from ASHRAE.Library of Congress Cataloging-

5、in-Publication DataThe ASHRAE guide for buildings in hot and humid climates / Lewis G. Harriman III . et al. - 2nd ed.p. cm.Summary: “Focuses on needs of owners, architects and engineers who build and manage buildings in hot and humid climates; includes info on building enclosures, dehumidification,

6、 sustainability, mold avoidance, energy reduction, moisture management and techniques for reducing energy consumption in hot and humid climates, based on real-world field experience and ASHRAE research”-Provided by publisher.Includes bibliographical references.ISBN 978-1-933742-43-4 (hardcover)1. Ai

7、r conditioning. 2. Building-Tropical conditions. 3. Dampness in buildings-Prevention. 4. Humidity-Control. I. Harriman, Lewis G., 1949- II. Title: Guide for buildings in hot and humid climates.TH7687.A785 2009697.93-dc222008049708The ASHRAE Guide for Buildings in Hot and Humid Climates - Second Edit

8、ionISBN 978-1-933742-43-42009 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.1791 Tullie Circle, NEAtlanta, GA 30329www.ashrae.orgAll rights reservedPrinted in the United States of AmericaPrinted using soy-based inks.Special Publications Cindy Sheffield Michaels Assoc

9、iate EditorJames Madison WalkerAssistant EditorAmelia Sanders Assistant EditorMichshell Phillips Administrative AssistantPublisher W. Stephen ComstockASHRAE StaffPublishing ServicesDavid Soltis Group Manager of Publishing Services and Electronic CommunicationsTracy Becker Graphic Applications Specia

10、listJayne Jackson Publications Traffic AdministratorFront_Matter_10_29_08.indd 2 11/21/08 3:18:15 PMFront_Matter_10_29_08.indd 3 11/21/08 3:18:16 PMPreface To The 2nd EditionThe first edition of this book contained a subset of the informa-tion we provide here. It dealt with the broad, cross-cutting

11、issues of thermal comfort, ventilation air, energy consumption and mold. In this 2nd edition, the book has expanded from 100 to over 300 pages.As the book expanded, it became apparent that although experts often agree about general principles, digging into the details some-times generates passionate

12、 debate. Strongly-held opinions based on decades of the different experiences of our expert advisors made writing this second edition quite a challenge.So its useful to keep in mind that the suggestions presented in this book include a broad range of opinions and judgements. It is quite possibleeven

13、 probablethat there will be different opinions between experts about any single suggestion. But the authors trust and expect that taken as a whole, the information provided here will be helpful when making the key decisions about design and operation of buildings in hot and humid climates.Above all,

14、 what we have tried to achieve is a clear and engaging presentation of the critical issues. Most experts will probably agree that as long as the key issues are given some attention, more often than not the building will be quite successful. Its when the decision makers are simply not aware of the is

15、sues that the real problems occur.For example, its not obvious to most architectural designers that the design of a buildings glazing will govern the comfort of the occupants, the cost of its HVAC system and the buildings energy use for all time. Nor is it obvious to HVAC designers that sealing up t

16、he connections in exhaust duct work will greatly reduce the risk of mold. But when the entire team is aware of the importance of glass design, the importance of overhanging the roof and importance of sealed duct connections, the decisions the team makes on behalf of the owner are likely to be better

17、. Then we will have achieved the purpose of this book: to improve buildings in hot and humid climates for the benefit of their owners, for their occupants and for society as a whole.AcknowledgmentsThis book was prompted by the long-standing sustainability concerns of Terry Townsend, P.E., President

18、of ASHRAE during 2006 and 2007. Based on his concern that without ASHRAE guidance, hot and humid climate design practices may not be as sustainable as what will be needed by future generations, President Townsend asked the ASHRAE Board to approve this special project. This expanded second edition ha

19、s been made possible by the technical and financial support of: the Office of Building Technologies of the U.S. Department of Energy; the Commercial Systems Division of Munters Corporation in San Antonio, Texas; the Services Division of the Southern Companies in Birmingham, Alabama and Venmar CES In

20、c. in St-Lonard-dAston, Quebec. On behalf of the Project Committee and of the future readership of this book, we express our great appreciation for the support of these generous sponsors, without whom this second edition could not exist.DedicationWe also appreciate the support of the many donors of

21、the technical material, photos, diagrams and field experiences which enrich and enliven this book. General principles, while useful, are much easier to understand, to remember and to apply when their relevance is made clear through real-world experience and examples. We are very grateful for those e

22、xperiences, and for the enormous amount of time volunteered by our reviewers and by our Project Monitoring Committee to help improve the text. Wherever the book is clear, ac-curate and useful, it is largely because of the contributions and the oversight of these generous experts. To them, we dedicat

23、e this second edition.Lew HarrimanPortsmouth, NHJanuary, 2009Front_Matter_10_29_08.indd 4 11/21/08 3:18:16 PMTable of Contents 51. Introduction 82. Improving Thermal Comfort 12Key Points .13Thermal Comfort - A Moving Target .13Thermal comfort is governed by expectations . 14Improving the percentage

24、of comfortable people . 14Dynamic & social nature of comfort perception 15Avoiding cold buildings in hot climates . 16Architecture - The Foundation of Comfort .17HVAC Suggestions for Better Comfort .211. Design HVAC systems for real clothing preferences 212. Dry ventilation air helps avoid temperatu

25、re swings 223. Constantly-cold coils can also dry air effectively 224. Drier air expands the comfort range in mixed uses. 235. Capacity modulation avoids sharp changes . 246. Higher velocity diffusers avoid “cold air dumping” . 253. Managing Ventilation Air . 28Key Points .29Measuring and conserving

26、 ventilation air .29Drying ventilation airall the time .32Avoiding building suction and infiltration 34Greater O & M attention for ventilation components 354. Reducing Energy Consumption 38Key Points .39Suggestions For Reducing Energy Use 421. Reduce the cooling load from windows 432. Avoid west-fac

27、ing glass . 453. Reduce the heat from lights, using daylighting 464. Build an air tight exterior enclosure . 495. Commission new buildings and mechanical systems . 516. Seal up all duct connections, air handlers and plenums 547. Reduce ventilation air when occupants leave . 558. Recover waste energy

28、 from exhaust air and condensers 569. First lower the dew point. then raise the thermostat. 5910. Invest in regular tune-ups (Constant commissioning). 615. Avoiding Bugs, Mold & Rot 68Key Points .69Excess Moisture Leads to Bugs, Mold & Rot 69Human Health Effects of Bugs, Mold & Rot 70Lessons Learned

29、 and Forgotten 70Mold growth - water activity vs. rh .71The ownernot the lawmakes the key decisions 74Suggestions for owners and Architects 74Suggestions for the HVAC designer .81Suggestions for contractors 84Suggestions for building operators 87Assessing Mold Risk in Existing Buildings 89Bacteria:

30、locate any standing water, then drain it or dry it 89Mold - keep moisture content below 14% WME 90Measuring moisture 91Locating excess moisture in buildings . 92Risky Misconceptions and Half-truths .976. Improving Sustainability .106Key Points .107Advancing Beyond Theory To Practice107Chapter 6 is a

31、n index to sustainability decisions .108More Durable = More Sustainable .108Dont build in flood zones and swamps 108Enclosure design which keeps out water .109Materials which tolerate frequent wetting .109Less Energy = More Sustainable 110Enclosure design which keeps out heat and humidity 110HVAC de

32、sign which keeps out heat and humidity .111HVAC design which matches energy to occupancy .111More Maintainable = More Sustainable 111Accounting allowsor preventssustainability111Budget for constant commissioningthen do it .112Access, access, access .113Common Issues In Hot & Humid ClimatesFront_Matt

33、er_10_29_08.indd 5 11/21/08 3:18:17 PMTable of Contents67. Elements of a Perfect Wall .116Towards a Perfect Wall .117The layers are the same for roofs and foundations .118Wall and roof layers must connect .119Translating basic principles into real walls .1198. Keeping Water Out .122Key Points .123Ro

34、of Overhangs Come First 124Sill Pans .126Flashing .126Drainage Planes In Walls .128Crawl Spaces .133Site and Foundation Drainage .1359. Keeping Heat Out140Key Points .141Owner & Architectural Designer Decisions 141Reduce the glazing and shade the remainder 141Design high, horizontal glazing for dayl

35、ighting .143Control lighting power according to daylight145Install continuous insulation, outboard146Allow money for demand-controlled ventilation 147Allow ceiling height for ducted supply and return .148HVAC Designer Decisions 149Seal up all air-side joints and connections .149Dont use building cav

36、ities to carry supply or return air .150Install demand-controlled ventilation 151Dont let air economizers fill the building with humid air 151Use exhaust air to precool and predry ventilation air .152Keep the indoor dew point low15310. Lessons From Storms .156Resisting wind and rain 157Resisting sto

37、rm surges and floods 157Materials and assemblies which tolerate water 158Assemblies which dry easily 16211. Dehumidification Loads 166Dehumidification (DH) Loads .167The Estimate Begins With Owners Decisions 167Step 1 - Selecting the outdoor design condition 167Step 2 - Selecting the target maximum

38、indoor dew point.168Step 3 - Quantifying & locating the people in the building .169After Owners Decisions, Engineering Begins 171Step 4 - Estimating the ventilation & makeup air load.171Step 5 - Estimating the infiltration load 172Step 6 - Estimating the load from people .174Step 7 - Estimating the

39、load from door openings .175Step 8 - Estimating the minor loads 17712. Cooling Loads .190Key Points .191Quantify glass-related loads to improve design .191Separate and calculate the dehumidification loads 195Calculate ventilation loads at peak dew point 197Enthalpy heat recovery reduces peak cooling

40、 loads 198Dont overestimate office plug loads 19913. Dehumidification Systems .202Key Points .203Deliver air drier than the control condition .204Control requires dedicated DH components .204Size DH equipment based on the peak dew point 205DH performance based on weight of water removed . 207Design

41、for dew point control instead of rh control 211Avoiding common problems in DH design .212Ways to reduce DH-related energy 21714. Cooling Systems 224Key Points .225Independent dehumidification and ventilation .225Extra cooling capacity does not dehumidify .227Dont double-up the safety factors .229Mea

42、sure, control and dry the ventilation air .231The Building Enclosure HVAC DesignFront_Matter_10_29_08.indd 6 11/21/08 3:18:17 PMTable of Contents 7Focus carefully on the exterior glass .232Design air systems which are really air-tight .233Cautions for buildings with operable windows 234Cautions for

43、comfort in hot and humid climates .23515. Ventilation Air Systems .238Key Points .239Ventilation Dehumidification and Air Cleaning .240Drying ventilation air .240Filtering particles .242Filtering gaseous pollutants - emphasizing ozone .245Effective Ventilation Air Distribution .246Reducing The Cost

44、Of Ventilation248How Much Air & Where - ASHRAE Std 62.1 .254Access for maintenance is now a requirement .259Use the peak dew point for DH calculations .25965% rh upper limit - a 55F dew point is a better one . 260Key Maintenance Aspects Of Ventilation 26316. Airtight HVAC Systems 270Key Points .271A

45、irtight Systems. Are They Necessary? 271Energy consumption and leaky air systems 271Mold and leaky air systems .272How Much Building Leakage Is HVAC-Driven? 272Designers Guide To Limiting Air Leakage .277Avoid return and supply air plenums 277Roof curbs .278Connections to and from air handlers 279Se

46、al all supply, return and exhaust air duct connections 279In-wall packaged AC units and fan-coil units .279Owners Guide To Reducing Air Leakage 280Tracking down leak locations 28317. Avoiding Mold by Keeping Construction DryKey Points .289Cautions for Each Construction Phase 290Exposed phase - Keep

47、fibrous glass insulation dry .290Partially-enclosed - Allow concrete and fireproofing to dry290Controlled phase - Watch out for wall board, and for HVAC292How Dry Is Dry Enough To Prevent Mold?.294Measuring Moisture 2961. Electrical Resistance - “Penetrating Meters” 2962. Electrical field variation

48、- “Non-Penetrating Meters” 2983. Equilibrium Relative Humidity (ERH) .2994. Vapor emission rate - The “Calcium chloride test” .301Equipment For Construction Drying 302Construction Drying Techniques .302Specifications To Keep New Construction Dry.305Appendix 308Psychrometric Display - Design vs. Hour

49、ly Weather.308Tampa, FL - (I-P units) .308Tampa, FL - (SI units) .309Dehumidification Design Equations 310I-P to SI Conversion Factors 311Dew Point and Humidity Ratio Tables 312Psychrometric Charts (showing gr/lb and g/kg) .314I-P .314SI .315Book Production Notes .316HVAC Design ConstructionFront_Matter_10_29_08.indd 7 11/21/08 3:18:17 PMChapter 1IntroductionFig. 1.1 Hot & Humid ClimatesIn mixed climates like Chicagos, there are certainly many hours each summer wh