CALIFORNIA ENERGY COMMISSION Advanced Variable Air Volume System Design Guide UIDELINES G ESIGN D October 2003 P500-03-082-A-11 Gray Davis, Governor CALIFORNIA ENERGY COMMISSION Prepared By: Taylor Engineering Mark Hydeman Steve Taylor Jeff Stein Eley Associates Erik Kolderup Tianzhen Hong Managed By: New Buildings Institute Cathy Higgins, Program Director White Salmon, WA CEC Contract No. 400-99-013 Prepared For: Donald Aumann, Contract Manager Nancy Jenkins, PIER Buildings Program Manager Terry Surles, PIER Program Director Robert L. Therkelsen Executive Director DISCLAIMER This report was prepared as the result of work sponsored by the California Energy Commission. It does not necessarily represent the views of the Energy Commission, its employees or the State of California. The Energy Commission, the State of California, its employees, contractors and subcontractors make no warrant, express or implied, and assume no legal liability for the information in this report; nor does any party represent that the uses of this information will not infringe upon privately owned rights. This report has not been approved or disapproved by the California Energy Commission nor has the California Energy Commission passed upon the accuracy or adequacy of the information in this report. Advanced VAV System Design Guide Acknowledgements Acknowledgements Project Director: Erik Kolderup, Eley Associates. Principal Investigator: Mark Hydeman, Taylor Engineering. Research Team: Steve Taylor and Jeff Stein, Taylor Engineering; Tianzhen Hong and John Arent, Eley Associates. Editing and Document Production: Kimberly Got, Zelaikha Akram, and Debra Janis, Eley Associates. Review and Advisory Committee: Karl Brown, CIEE; David Claridge, Texas A&M; Paul Dupont, Dupont Engineering; Ken Gillespie, Pacific Gas & Electric; Tom Hartman, the Hartman Company; Henry Lau, Southern California Edison; and David Sellers, PECI, Inc. Project Management: Cathy Higgins, Program Director for the New Buildings Institute and Don Aumann, Contract Manager for the California Energy Commission. Additional review was provided by Alan Cowan and Jeff Johnson, New Buildings Institute. i Advanced VAV System Design Guide Preface Preface The Advanced Variable Air Volume (VAV) System Design Guide (Design Guide) provides a powerful new resource for Heating, Ventilation, and Air- Conditioning (HVAC) designers. It presents brand new information on fan selection and modeling and provides the most current recommendations on VAV airside system design. Total large office building energy savings of up to 12% are achievable by applying the …a powerful new resource for recommendations in the Design Guide resulting in heating,ventilation, and air an estimated annual statewide savings of 2,220 conditioning designers. MWh/yr for new large office construction. The Design Guide is a product of a three-year research project that included field monitoring of five sites with built-up VAV systems. It contains measures and recommendations from a range of sources including our research, associated research1, ASHRAE Guidelines and Standards, Title 24, team experience gained in the design and commissioning of mechanical systems and controls for commercial buildings and in performing peer reviews of mechanical designs of commercial buildings. Throughout this document we refer to standard practice. This is a subjective benchmark that is determined based on our experience as mechanical engineers, reviewing the work of other firms, and through our conversations with manufacturers and contractors. The Advanced VAV System Design Guide was developed as part of the Integrated Energy Systems — Productivity and Building Science project, a Public Interest Energy Research (PIER) program administered by the California Energy Commission under contract No. 400-99-013, and managed by the New Buildings Institute. The Buildings Program Area within the PIER Program produced this Design Guide. The program includes new and existing buildings in both the residential and the non-residential sectors. It seeks to decrease building energy use through research that will develop or improve energy efficient technologies, strategies, tools, and building performance evaluation methods. This document is part of report #P500-03-082 (Attachment A-11 Product 3.6.2).. For other reports produced within this contract or to obtain more information on the PIER Program, please see Project Reports in Appendix 7, visit www.energy.ca.gov/pier/buildings or contact the Commission’s Publications Unit at 916-654-5200. The Design Guide is also available at www.newbuildings.org 1 PIER, ASHRAE, CBE and others ii Advanced VAV System Design Guide Abstract Abstract The Advanced Variable Air Volume (VAV) System Design Guide (Design Guide) is written for Heating, Ventilation, and Air-Conditioning (HVAC) designers and focuses on built-up VAV systems in multi-story commercial office buildings in California. The Design Guide recommendations include best practices for airside system design, covering fans, air handlers, ducts, terminal units, diffusers, and controls, with emphasis on getting the air distribution system components to work together in an integrated fashion. Key topics critical to optimal VAV design and performance are addressed in the following chapters: 1) early design issues, 2) zone issues, 3) VAV box selection, 4) duct design, 5) supply air temperature reset, 5) fan type, size and control, 6) coils and filters, and 7) outdoor air, return air and exhaust air. The intent of the information is to promote efficient, practical designs that advance standard practice, achieve cost effective energy savings and can be implemented using current technology. Author: Mark Hydeman, Steve Taylor, Jeff Stein, Taylor Engineering. Erik Kolderup, Eley Associates Keywords: Variable Air Volume, VAV, HVAC, Fans, Ducts, Commercial Building, Distribution System, Energy Savings iii Advanced VAV System Design Guide Abstract iv Advanced VAV System Guideline Table of Contents TABLE OF CONTENTS ACKNOWLEDGEMENTS ..........................................................................................................................I PREFACE.................................................................................................................................................... II ABSTRACT ................................................................................................................................................III OVERVIEW ................................................................................................................................................. 1 AUDIENCE & OBJECTIVES ........................................................................................................................... 1 KEY RECOMMENDATIONS ........................................................................................................................... 1 ENERGY IMPACTS........................................................................................................................................ 4 DESIGN GUIDE ORGANIZATION................................................................................................................... 5 INTRODUCTION........................................................................................................................................ 9 OBJECTIVE .................................................................................................................................................. 9 ROLE OF THE DESIGNER ............................................................................................................................ 10 MARKET SHARE ........................................................................................................................................ 10 EARLY DESIGN ISSUES......................................................................................................................... 13 INTEGRATED DESIGN ISSUES..................................................................................................................... 13 THE ROLE OF SIMULATION IN DESIGN....................................................................................................... 15 HVAC SYSTEM SELECTION ...................................................................................................................... 21 LOCATION AND SIZE OF AIRSHAFTS .......................................................................................................... 27 RETURN AIR SYSTEM ................................................................................................................................29 AUXILIARY LOADS.................................................................................................................................... 31 DESIGN AIRSIDE SUPPLY TEMPERATURE .................................................................................................. 32 CODE VENTILATION REQUIREMENTS ........................................................................................................ 34 DETERMINING INTERNAL LOADS .............................................................................................................. 35 SIMULATION AND PERFORMANCE TARGETS.............................................................................................. 46 ZONE ISSUES............................................................................................................................................ 49 THERMAL