TABLE OF CONTENTS Preface........................................................................................................................................ vi Overview ..................................................................................................................................... 1 Audience and Objectives.......................................................................................... 1 Key Recommendations ............................................................................................ 2 Energy Impacts.......................................................................................................... 4 Design Guide Organization ..................................................................................... 6 Introduction................................................................................................................................ 9 Objective ...................................................................................................................... 9 Role of the Designer................................................................................................10 Market Share............................................................................................................11 Integrated Design Issues.......................................................................................14 The Role of Simulation in Design ........................................................................16 HVAC System Selection..........................................................................................22 Location and Size of Airshafts..............................................................................28 Return Air System...................................................................................................30 Auxiliary Loads........................................................................................................33 Design Airside Supply Temperature ..................................................................34 Code Ventilation Requirements ...........................................................................36 Determining Internal Loads..................................................................................37 Simulation and Performance Targets................................................................47 Zone Issues...............................................................................................................................50 Thermal Comfort .....................................................................................................50 Zoning and Thermostats .......................................................................................52 Demand Control Ventilation (DCV).......................................................................53 Occupancy Controls ................................................................................................57 Window Switches....................................................................................................57 Design of Conference Rooms................................................................................58 VAV box selection....................................................................................................................60 VAV Box Selection Summary................................................................................60 VAV Reheat Box Control.........................................................................................61 Minimum Airflow Setpoints..................................................................................67 Sizing VAV Reheat Boxes ......................................................................................75 Other Box Types.......................................................................................................81 Other Issues..............................................................................................................88 Duct Design...............................................................................................................................93 General Guidelines..................................................................................................93 Supply Duct Sizing ..................................................................................................99 XiX Return Air System Sizing....................................................................................104 Fan Outlet Conditions ...........................................................................................105 Noise Control..........................................................................................................106 Supply Air Temperature Control.......................................................................................110 Optimal Supply Air Temperature......................................................................110 Recommended Sequence of Operation.............................................................112 System Design Issues..........................................................................................113 Code Requirements ..............................................................................................114 Fan Type, Size and Control.................................................................................................115 Fan Selection Criteria ..........................................................................................115 Visualizing Fan Performance ............................................................................119 Fan Selection Case Studies.................................................................................126 Comparing Manufacturers .................................................................................146 Fan Control .............................................................................................................147 Conclusions............................................................................................................161 Coils and Filters ....................................................................................................................163 Construction Filters..............................................................................................163 Pre-Filters...............................................................................................................163 Final Filter Selection ............................................................................................163 Filter Area...............................................................................................................164 Extended Surface Area Filters ...........................................................................164 Monitoring Filters.................................................................................................164 Coil Selection..........................................................................................................165 Coil Bypass.............................................................................................................167 Outside Air/Return Air/Exhaust Air Control.................................................................168 Control of Minimum Outdoor Air for VAV Systems.......................................168 Isolation Zones ......................................................................................................176 Design of Airside Economizer Systems...........................................................176 Economizer Temperature Control ....................................................................181 Economizer High-Limit Switches......................................................................182 Appendix 1 – Monitoring Sites...........................................................................................184 Site 1 ........................................................................................................................184 Site 2 ........................................................................................................................186 Site 3 ........................................................................................................................188 Site 4 ........................................................................................................................189 Site 5 ........................................................................................................................190 Appendix 2 – Measured Fan Performance......................................................................192 Energy Benchmark Data .....................................................................................192 xiiX Appendix 3 – Airflow in the Real World.......................................................................... 196 Interior Zone Airflow........................................................................................... 196 Perimeter Zone Airflow ...................................................................................... 198 System Level Airflow........................................................................................... 200 Appendix 4 – Cooling Loads in the Real World.............................................................. 203 Appendix 5 – DOE-2 Fan Curves....................................................................................... 206 Appendix