Guidelines for Energy Efficient Commercial Unitary HVAC Systems Final Report Revised January 19 2001 Prepared for Consortium for Energy Efficiency One State Street Suite 1400 Boston MA 02109 3507 Contact Denise Rouleau 2001 Consortium for Energy Efficiency All rights reserved Guidelines for Energy Efficient Commercial Unitary HVAC Systems TABLE OF CONTENTS 1 INTRODUCTION 1 1 1 Executive Summary 1 2 Applications 1 3 Benefits Due to Energy Efficient Installation Practices 1 4 How to Use This Document 1 5 References and Acknowledgements 2 UNITARY AIR CONDITIONERS AND HEAT PUMPS 4 2 1 Load Calculation New or Retrofit Construction 2 1 1 Benefits 2 1 2 Methodology 2 1 3 Design Conditions 2 1 4 Peak Load Reduction 2 1 5 Selecting Unit Capacity to Meet Calculated Loads 2 2 Equipment Selection 2 2 1 Benefits 2 2 2 Efficiency Standards for New Equipment 2 2 3 Evaluation Replacement of Existing Units 2 2 4 Selection of Heating Equipment 2 3 Unit Configuration and Location 2 3 1 Benefits 2 3 2 Best Practices 2 4 Unit Installation 2 4 1 Benefits 2 4 2 Sealing Around Rooftop Units 2 4 3 Split System Refrigeration Piping 2 5 Economizers 2 5 1 Benefits 2 5 2 Best Practices 2 5 3 Economizer Retrofits 2 5 4 Economizer Components New or Retrofit 2 6 Energy Efficient Ventilation 2 6 1 Benefits 2 6 2 Methodology 2 7 Additional Options Accessories 2 7 1 Benefits 2 7 2 Options for Increasing Energy Efficiency 3 AIR DISTRIBUTION 13 Final Report i 1 19 01 Guidelines for Energy Efficient Commercial Unitary HVAC Systems 3 1 Zoning 3 1 1 Benefits 3 1 2 Best Practices 3 2 Distribution System Types 3 2 1 Best Practices for Constant Volume CV Systems 3 2 2 Best Practices for Variable Air Volume VAV Systems 3 2 3 Best Practices for Constant to Variable Volume Retrofits 3 2 4 Best Practices for Variable Volume Temperature VVT Systems 3 3 Duct System Types 3 4 Duct System Parameters 3 4 1 Benefits 3 4 2 Duct Locations 3 4 3 Duct Accessory Selection 3 4 4 Duct System Design 3 4 5 Duct Layout 3 4 6 Duct Velocity 3 4 7 Design Pressure 3 5 Ductwork Installation 3 5 1 Benefits 3 5 2 Duct Construction 3 5 3 Air Plenum Construction 3 5 4 Duct Sealing 3 5 5 Duct Insulation Liners 3 6 Evaluation of Existing Ductwork Systems for Retrofit 3 7 Reconditioning Existing Ductwork Systems 3 7 1 Benefits 3 7 2 Best Practices 4 CONTROLS 22 4 1 Benefits 4 2 Best Practices 4 3 Controls Retrofits 4 3 1 Benefits 4 3 2 Evaluating Existing Controls 4 4 Systemwide Controls 4 5 Fan Controls 4 5 1 Benefits 4 5 2 Methodology 4 6 Night Ventilation 4 6 1 Benefits 4 6 2 Best Practices 5 HVAC COMMISSIONING NEW EXISTING SYSTEMS 25 Final Report ii 1 19 01 Guidelines for Energy Efficient Commercial Unitary HVAC Systems 5 1 Benefits 5 2 General 5 2 1 Existing Retrofit Systems 5 3 Commissioning Personnel 5 4 Documentation 5 4 1 HVAC Commissioning Plan 5 4 2 HVAC Commissioning Report 5 4 3 Operation Maintenance Manual 5 5 Commissioning Best Practices 5 6 Commissioning Unitary Equipment 5 6 1 General 5 6 2 Functional Testing of Roof Top Units 5 6 3 Air Handling Equipment 5 6 4 Cooling Equipment 5 6 5 Refrigerant Charge 5 6 6 Heating Equipment 5 6 7 Economizers 5 7 Commissioning Ductwork Systems 5 7 1 General 5 7 2 Duct Plenum Construction 5 7 3 Duct Air Leakage 5 7 4 Duct Insulation Liners 5 7 5 Air Terminals 5 8 Testing Balancing 5 9 Commissioning Controls 5 9 1 General 5 9 2 Energy Management Systems 5 10 Training 5 11 Operation Maintenance O M 5 11 1 Benefits 5 11 2 Best Practices 5 11 3 O M Checklist 6 DEFINITIONS 36 7 REFERENCES 40 Final Report iii 1 19 01 Guidelines for Energy Efficient Commercial Unitary HVAC Systems 1 INTRODUCTION 1 1 EXECUTIVE SUMMARY This specification is a compilation of energy efficient best practices for the sizing selection installation and commissioning of unitary air source air conditioner and heat pump systems up to 30 tons Commercial new and retrofit construction projects are included This document is intended as a tool for improving the energy efficiency of commercial unitary HVAC installations which make up approximately 55 percent of the total annual tonnage of commercial HVAC equipment sold in the United States 15 The purpose of this document is to facilitate implementation of energy efficient installation practices by providing a specification guide that can easily be used by key people in the industry namely installing contractors service providers and designers In addition this document may be used as a specification for equipment manufacturers and incentive programs and as a training tool for program managers The program goal is a substantial increase in commercial HVAC energy efficiency with reduced construction and energy costs as the incentive The following table highlights key energy saving practices Key Elements for Energy Efficient Installations Element Load Calculations Unit Selection Ductwork Design System Installation Controls Commissioning Operation Maintenance Specification for Best Practices Section 2 1 calculate loads using ASHRAE Fundamentals2a ACCA Manual N17 or software based upon these methods34 Section 2 2 CEE HECAC Initiative1 for new equipment Minimum Efficiency Tier 1 Premium Efficiency Tier 2 Section 3 installation should comply with ASHRAE Fundamentals2a ACCA Manual N1 or SMACNA HVAC Systems Duct Design12d Sections 2 4 manufacturer s instructions SMACNA HVAC Duct Construction Stds12a and ASHRAE 90 1 19992a Potential Energy Savings Up to 50 percent efficiency increase when compared with substantially oversized equipment4 10 20 percent compared with U S Fed minimum efficiency units4 or up to 40 percent compared with older units 15b Section 4 design installation per ASHRAE 90 1 19992a Section 5 mgr s instructions Section 5 manufacturer s instructions Economizers may save 15 80 percent of cooling energy4 Up to 20 percent energy savings18 11 42 percent energy savings16 Varies Up to 20 percent supply air leakage can result in a 60 70 percent increase in fan power19 savings are not additive Final Report 1 1 19 01 Guidelines for Energy Efficient Commercial Unitary HVAC Systems 1 2 APPLICATIONS This document provides specifications for energy efficient installation practices relating to the following commercial systems Unitary Air Conditioners and Air to Air Heat Pumps up to 30 tons capacity including packaged rooftop units and matched split systems Built up systems packaged terminal air conditioners through the wall chilled water systems and water cooled equipment are not included Heating
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