AIVC Guide to Ventilation i This report is part of the work of the IEA Energy Conservation in Building & Community Systems Programme. Publication prepared by Annex V Air Infiltration and Ventilation Centre Document AIC-TN-VENTGUIDE-1996 Distribution: Annex V only ISBN 0 946075 85 9 Additional copies of this report may be obtained from: Participating countries: The Air Infiltration and Ventilation Centre Annex V University of Warwick Science Park Belgium, Denmark, Finland, France, Germany, Sovereign Court Greece, Netherlands, New Zealand, Norway, Sir William Lyons Road Sweden, United Kingdom and the United States of Coventry CV4 7EZ America Great Britain 2 AIVC Guide to Ventilation A Guide to Energy Efficient Ventilation Martin W Liddament March, 1996 AIVC Guide to Ventilation 3 Copyright Oscar Faber plc 1996 All property rights, including copying are vested in the Operating Agent (Oscar Faber Consulting Engineers) on behalf of the International Energy Agency. In particular, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the Operating Agent. 4 AIVC Guide to Ventilation Preface International Energy Agency The International Energy Agency (IEA) was established in 1974 within the framework of the Organisation for Economic Co-operation and Development (OECD) to implement an International Energy Programme. A basic aim of the IEA is to foster co-operation among the twenty four IEA Participating Countries to increase energy security through energy conservation, development of alternative energy sources and energy research development and demonstration (RD&D). Energy Conservation in Buildings and Community Systems The IEA sponsors research and development in a number of areas related to energy. In one of these areas, energy conservation in buildings, the IEA is sponsoring various exercises to predict more accurately the energy use of buildings, including comparison of existing computer programs, building monitoring, comparison of calculation methods, as well as air quality and studies of occupancy. The Executive Committee Overall control of the programme is maintained by an Executive Committee, which not only monitors existing projects but identifies new areas where collaborative effort may be beneficial. To date the following have been initiated by the Executive Committee (completed projects are identified by *): I Load Energy Determination of Buildings* II Ekistics and Advanced Community Energy Systems* III Energy Conservation in Residential Buildings* IV Glasgow Commercial Building Monitoring* V Air Infiltration and Ventilation Centre VI Energy Systems and Design of Communities* VII Local Government Energy Planning* VIII Inhabitant Behaviour with Regard to Ventilation* IX Minimum Ventilation Rates* X Building HVAC Systems Simulation* XI Energy Auditing* XII Windows and Fenestration* XIII Energy Management in Hospitals* XIV Condensation* XV Energy Efficiency in Schools* AIVC Guide to Ventilation 5 XVI BEMS - 1: Energy Management Procedures* XVII BEMS - 2: Evaluation and Emulation Techniques* XVIII Demand Controlled Ventilating Systems* XIX Low Slope Roof Systems* XX Air Flow Patterns within Buildings* XXI Thermal Modelling* XXII Energy Efficient Communities* XXIII Multizone Air Flow Modelling (COMIS)* XXIV Heat Air and Moisture Transfer in Envelopes* XXV Real Time HEVAC Simulation* XXVI Energy Efficient Ventilation of Large Enclosures* XXVII Evaluation and Demonstration of Domestic Ventilation Systems XXVIII Low Energy Cooling Systems XXIX Daylight in Buildings XXX Bringing Simulation to Application XXXI Energy Related Environmental Impact of Buildings XXXII Integral Building Envelope Performance Assessment XXXIII Advanced Local Energy Planning XXXIV Computer-aided Evaluation of HVAC System Performance XXXV Control Strategies for Hybrid Ventilation in New and Retrofitted Office Buildings (HYBVENT) XXXVI Retrofitting in Educational Buildings – Energy Concept Adviser for Technical Retrofit Measures XXXVII Low Exergy Systems for Heating and Cooling of Buildings Annex V Air Infiltration and Ventilation Centre The Air Infiltration and Ventilation Centre was established by the Executive Committee following unanimous agreement that more needed to be understood about the impact of air change on energy use and indoor air quality. The purpose of the Centre is to promote an understanding of the complex behaviour of air flow in buildings and to advance the effective application of associated energy saving measures in both the design of new buildings and the improvement of the existing building stock. The Participants in this task are Belgium, Denmark, Finland, France, Germany, Greece, Netherlands, New Zealand, Norway, Sweden, United Kingdom and the United States of America. 6 AIVC Guide to Ventilation Contents A Guide to Energy Efficient Ventilation Preface 5 Foreword 11 Acknowledgements 12 Introduction 15 Chapter 1: Rationale and Background to Ventilation 19 Summary and Introduction 19 What is Ventilation? 20 Why Is Ventilation Needed? 21 How Does Ventilation Work? 21 How Much Ventilation Is Needed? 23 When Is Ventilation Not Appropriate? 24 How Polluted Can a Building Become? 25 What is the Energy Impact of Ventilation? 26 Can Ventilation Energy Loss Be Avoided or Recovered? 26 What Is the Relationship Between Ventilation Rate and Odour? 27 Is There a Relationship Between Ventilation and Health? 28 How is Ventilation Provided? 28 How Do Ventilation Needs and Strategies Differ According to Building Type? 29 How Is the Choice of Ventilation Influenced By Climate and Local Environment? 30 What Regulations and Standards Govern the Choice and Performance of Ventilation Systems? 30 What Other Aspects Must be Considered in the Design Process? 30 Can Ventilation be Used for Cooling? 31 Can Outdoor Air be Cleaned? 31 What is Ventilation Efficiency? 32 What Provision Should be Made for Maintenance? 32 What Measurement Techniques are Available? 32 What Calculation Techniques are Available? 33 What Units are Used for Ventilation and Air Infiltration? 35 References 35 Chapter 2: Indoor Air Quality and Comfort 37 Summary and Introduction 37 2.1 Sick Building Syndrome 39 2.2 Pollutants and Pollutant Sources 41 2.3 Reducing Indoor Pollutant Concentration 46 2.4 Comfort and Wellbeing 48 References 54 Chapter 3: The Energy Impact of Ventilation and Air Infiltration 57 Summary and Introduction 57 3.1 Definitions Relating to Energy Impact 58 3.2 Estimating Energy Impact 61 3.3 Energy Impact of Ventilation and Air Infiltration 66 3.4 The Potential for Reducing Energy Impact 68 References 69 AIVC Guide to Ventilation 7 Chapter 4: Design Criteria 71 Summary and Introduction 71 4.1 Design Parameters 72 4.2 Ventilation Need 72 4.3 Design Constraints 73 4.4 Design Variables 82 References 84 Chapter 5: Ventilation Strategies 87 Summary and Introduction 87 5.1 Natural Ventilation 87 5.2 Mechanical Ventilation 99 References 115 Chapter 6: Ventilation Heat Recovery 117 Summary and Introduction 117 6.1 Definitions Relating to Heat Recovery 118 6.2 Ventilation Heat Recovery Techniques 118 6.3 Air-to-Air Heat Recovery 119 6.4 Heat Pumps 125 6.5 Dynamic Insulation 129 6.6 ‘Ground’ Pre-heat Recovery 132 References 133 Chapter 7: Ventilation and Cooling 135 Summary and Introduction 135 7.1 Cooling in Relation to Ventilation Strategy 136 7.2 Passive and Mixed Mode Techniques 139 7.3 Reducing the Need for Cooling 141 References 145 Chapter 8: Air Cleaning by Filtration 147 Summary and Introduction 147 8.1 Particulates 147 8.2 Reducing Particulate Concentration by Filtration 150 References 157 Chapter 9: Ventilation Efficiency 159 Summary and Introduction 159 9.1 Concepts of Ventilation Efficiency 160 9.2 Air Change Efficiency 161 9.3 Contaminant Removal Effectiveness 162 9.4 Evaluating Ventilation Efficiency Parameters 165 9.5 Examples of Applying Concepts of Ventilation Efficiency 166 References 167 8 AIVC Guide to Ventilation Chapter 10: Maintenance and Designing for Maintenance 169 Summary and Introduction 169 10.1 Design for Ease of Maintenance 170 10.2 Maintenance of Specific Components 172 10.3 Maintenance Design for Large Buildings 175 10.4 Implementing Maintenance Regulations and Standards 177 References 178 Chapter 11: Measurement Methods 181 Summary and Introduction 181 11.1 Tracer Gas Methods 182 11.2 Pressurisation Methods 193 11.3 Component Air-tightness Testing 197 11.4 Other Measurement Methods 198 11.5 Instrumentation for Tracer Gas Detection 208 11.6 Theoretical Outline 210 References 213 Chapter 12: Calculation Methods 215 Summary and Introduction 215 12.1 Applications 217 12.2 Generic Calculation Methods 217 12.3 Estimation from Building Air-tightness Data 218 12.4 ‘Simplified’ Theoretical Models 220 12.5 Network (zonal) Models 222 12.6 Explicit Network Methods 235 12.7 Computational Fluid Dynamics 237 12.8 Ventilation and Air Flow Related Calculations 241 12.9 Combined Thermal and Ventilation Models 246 References 249 Appendix 1 251 Air Leakage Characteristics of Building Components 251 Appendix 2 257 Wind Pressure Coefficient Data 257 Appendix 3 261 AIDA – Air Infiltration Development Algorithm 261 Index 267 AIVC Guide to Ventilation 9 10 AIVC Guide to Ventilation Foreword Ventilation is the mechanism by which clean air is provided to a space. It is essential for meeting the metabolic needs of occupants and for diluting and removing pollutants emitted by indoor sources. On the other