Analysis and Design of Heating, Ventilating, and Air-Conditioning Systems Analysis and Design of Heating, Ventilating, and Air-Conditioning Systems Second Edition Herbert W. Stanford III and Adam F. Spach CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2019 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U. Government works Printed on acid-free paper International Standard Book Number-13: 978-1-138-60241-0 (Hardback) This book contains information obtained from authentic and highly regarded sources.
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For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.com and the CRC Press Web site at http://www.com Contents Preface.xv Section I Basic Concepts 1.1 Overview of HVAC.1 Definition of Air-Conditioning.2 Energy Impact of HVAC Systems.2 Buildings as Thermodynamic Systems.2 Energy Gains and Losses in Building Spaces.3 Building Envelope Design.3 Common HVAC Elements.1 Structural Support for HVAC Components.2 Electrical Aspects of HVAC Systems.4 Definitions of HVAC Terms. The Air-Conditioning Process.2 Air and Its Properties.3 Methods of Measurement and Analysis.1 Thermodynamic Wet-Bulb Temperature.3 The Psychrometric Chart.4 Typical Air-Conditioning Processes.1 Sensible Heating or Cooling.2 Combined Sensible and Latent Cooling (Dehumidification).3 Heating and Humidification.5 Psychrometric Analysis of Complete Systems.1 Space Heating and Cooling Loads.2 Sensible Cooling Load.3 Latent Cooling Loads.4 Psychrometric Chart Representation of Space Conditions.5 The Coil Line.6 Coil Contact and Bypass Factors.7 Psychrometric Analysis of Complete Systems.
HVAC Systems Concepts.2 All-Air Systems.1 Single-Zone Systems.3 Dual–Duct Systems.5 VAV/Variable Temperature Systems.3 Air–Water Secondary Systems.1 Active and Passive Chilled Beam Systems.2 FCUs and Unit Ventilators.4 Variable Refrigerant Flow Systems.1 The Heat Pump Concept.2 Air-Source Heat Pumps.3 Water-Source Heat Pumps.1 Closed Circuit Heat Pump Systems.2 Closed Circuit Geothermal Heat Pump Systems.3 Open Circuit Geothermal Heat Pump Systems.4 Gas-Fired Engine-Driven Heat Pumps.5 Heat Recovery Chiller/Heat Pump System.4 Advanced Technology Heat Pumps. 82 Section II The Design Method 4. HVAC Systems Design.2 Criteria for HVAC Design.3 Compliance with Building Codes and Standards.1 International Mechanical Code.2 International Energy Conservation Code.3 NFPA Standards and Guidelines.4 ASHRAE Standards and Guidelines.4 Designing for Maintainability.1 HVAC Equipment Location and Access.2 Mechanical Equipment Rooms for Air-Handling Equipment.3 Mechanical Equipment Rooms for Boilers and Chillers.4 Ceiling Cavity Space.5 Designing for Energy Conservation.1 Introduction to ASHRAE Standard 90.2 Simplified Energy Analysis.3 Building Energy Modeling.4 Exhaust Air Heat Recovery.5 Internal Source Heat Recovery.6 Thermal Energy Storage.6 Designing for Sustainability.1 High-Performance Building Elements.2 Introduction to ASHRAE Standard 189.3 Net Zero/Sum Zero-Energy Buildings.7 Construction Documents Quality Control. Heating/Cooling Load Calculation.1 Building Thermal Balance.2 Purpose of Load Calculations.2 Mechanics of Building Heat Loss and Gain.2 Heat Transfer through Walls and Roofs.3 Heat Transfer through Fenestration.4 Heat Loss through Floors and Basements.5 Internal Heat Gains.3 Load Computation Methodologies.1 Heat Balance and Radiant Time Series.2 Total Equivalent Temperature Difference with Time Averaging.4 Computer-Based Calculation Tools.5 Benchmark Heating/Cooling Loads.
Air Tempering and Distribution.1 Heating and Cooling Coils.1 Direct Expansion Refrigerant Cooling Coils.2 Chilled Water Cooling Coils.3 Hot Water Heating Coils.4 Steam Heating Coils.5 Electric Resistance Heating Coils.6 Preheating and Precooling Coils.7 Desiccant Cooling and Dehumidification.2 Air Distribution Design.1 Room Air Diffusion.2 Typical Air Distribution Patterns.3 Large Space Air Distribution.4 Displacement Ventilation Air Distribution.1 VAV Single-Duct TUs.2 VAV Single-Duct Fan-Powered TUs.3 VAV Dual Duct TUs.1 Steps in Duct System Design.2 Duct Air Balancing Rationale.2 Energy and Pressure Relationships.1 Calculation of Friction Losses in Ducts.2 Calculation of Friction Losses in Fittings.4 Methods of Duct Design.1 Constant Velocity Method.2 Velocity Reduction Method.3 Static Regain Method.4 Equal Friction Method.5 Duct Construction Criteria.6 Duct Design Guidelines.5 Special Exhaust Systems Design.1 Laboratory Exhaust Systems.2 Industrial Exhaust Systems.7 Fire and Smoke Control in Duct Systems.2 Weight Density, Specific Volume, and Specific Gravity.3 Mean Velocity of Flow.1 Pipe Routing and Sizing.2 Pressure Loss Calculation.3 Expansion and Air Removal.3 Steam and Condensate Piping.1 Pipe Routing and Sizing.2 Steam Trap Application and Sizing.3 Control of Steam Piping Expansion.1 Hot Piping Insulation.2 Cold Piping Insulation. 218 Contents ix Section III Systems and Components 9. Pumps and Fans.2 Pumps and Applications.1 Pump Types and Characteristics.3 Water Flow Volume Control.1 Fan Energy Relations.2 Fan Types and Characteristics.3 Fan and System Characteristics.5 Variable Air Volume Fan Control.4 Pump and Fan Affinity Laws. Terminal Systems and Components.1 Systems Types and Applications.1 Selecting the Right System for the Application.2 Space Needs and Other Requirements for Terminal Systems.2 AHUs and Components.2 Particulate Air Filtration.3 Gas-Phase Filtration.4 Ultraviolet Air and Surface Treatment.5 Airside Economizer Cycle.6 Cooling Coils Condensate Drainage.4 Ventilation and Building Pressurization.1 Outdoor Air Intakes.2 Understanding and Applying ASHRAE Standard 62.3 Demand Control Ventilation.4 Dedicated Outdoor Air Systems.
Refrigeration Systems and Components.2 Vapor Compression Refrigeration Cycle.3 Vapor Absorption Refrigeration Cycle.2 Direct Expansion Refrigeration Systems.3 Chilled Water Refrigeration Systems.1 Determining Chilled Water Supply Temperature.2 Establishing Chilled Water Temperature Range.3 Vapor Compression Cycle Water Chillers.4 Scroll Compressor Water Chillers.5 Rotary Screw Compressor Water Chillers.6 Centrifugal Compressor Water Chillers.7 Absorption Water Chillers.8 Chilled Water System Configurations.9 Chilled Water Buffer Tanks.4 Condensers and Cooling Towers.1 Air-Cooled Condensers.2 Cooling Tower Fundamentals.3 Tower Configuration and Application.4 Closed Circuit Evaporative Cooler.5 Evaporative Air Cooling.6 Waterside Economizer Cycle. Heating Systems and Components.1 Firing Fossil Fuels.1 Oil-Fired Systems.2 Gas-Fired Systems.1 Boiler Types, Ratings, and Efficiency.3 Boiler/Furnace Venting.4 Hydronic Heating Systems.5 Steam Heating Systems.2 Steam Heat Transfer.3 Steam-to-Water Heat Exchangers.5 Steam Pressure Reducing Valves.6 Steam Condensate Receivers and Pumps.2 DDC Input/Output Points.1 Input/Output Basics.3 Final Control Elements.4 Direct Digital Controllers and Systems.1 DDC System Architecture.2 Controllers and Control Loops.3 Networks and Communication.5 HVAC Sequences of Operation.6 DDC System Security.7 DDC System Design Checklist. 380 Section IV Special Considerations 14. Special HVAC Design Considerations.1 Indoor Air Quality.2 Antiterrorism Design for HVAC Systems.2 Terror Threats against Buildings.3 HVAC Design to Minimize Explosive Threats.4 HVAC Design to Minimize CBR Threats.3 HVAC Water Treatment.1 Hot and Chilled Water Systems Chemical Treatment.2 Evaporative Cooling Water Systems Chemical Treatment.3 Evaporative Cooling Water Systems Nonchemical Treatment.4 Steam and Condensate Systems Chemical Treatment.5 Legionella Risk Management in HVAC Water Systems.4 Vibration and Noise Mitigation.1 Noise Definition and Design Criteria.2 Indoor Noise Control in HVAC Systems.3 Outdoor Noise Issues in HVAC Systems.5 HVAC Systems Start-Up and Commissioning.1 HVAC Systems Operation Prior to Commissioning.2 The Commissioning Process.6 Correcting HVAC Performance for Altitude and Temperature.
Engineering Economics and Design Decision-Making.2 Defining HVAC Design Alternatives.3 Estimating Capital Requirements.1 Capital Cost Estimating.2 Time/Money Relationships.4 Recurring Costs Determination.5 Component Service Life and Replacement.6 Comparing Alternatives and Dealing with Uncertainty.1 Alternatives with Different Economic Lives.3 Selecting Alternatives within the Project Budget.7 Overview of LCCA.1 Basic Practices for LCCA.2 Calculations and Analysis Tools. Building Information Modeling.1 BIM Use by HVAC Designers.2 BIM Use by Contractors/Subcontractors.3 BIM Use by Owners. Construction Contract Administration.2 Design Period Considerations.3 Preconstruction Procedures and Practices.4 Construction Period Procedures and Practices.5 Completion and Closeout Procedures and Practices.6 Avoiding Litigation Pitfalls.7 Construction Administration Checklist.1 Construction Administration Practices and Procedures Checklist. 453 Index��������������������������������������������������������������������������������������������������������������������������������������������� 457 Preface The first edition of this book came about as the outgrowth of a conversation between a group of practicing heating, ventilating, and air-conditioning (HVAC) design engineers in 1983 concerning their dissatisfaction with both the textbooks used in HVAC college courses (what few there were) and the design handbooks then available.
Thus, I set out to write a text that I would have liked to have had as a student and one that I would have retained as a practicing engineer. I feel that the first edition had some success in meeting the following objectives: 1. To build a text around a strong “systems” point of view with emphasis on the energy consumption ramifications of design decisions 2. To primarily address HVAC applications for institutional, commercial, and indus- trial buildings 3.
To make this text valuable as a resource tool for the practicing engineer 4. To use the methodologies of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Handbook as the primary reference source. These objectives continue to apply in this second edition. Another major impetus to the writing of this book was the fact that for many years I made a very good living investigating and solving HVAC system operating problems in buildings, many of which were the result of inadequate or incorrect design.
Even now, a recent survey conducted by one major industry magazine indicates that the majority of all building owners queried responded that there were problems and ongoing dissatisfaction with the HVAC systems in their buildings. These experiences indicate that HVAC design engineers are still too often doing a less-than-adequate job in the delivery of the final product: an HVAC system that “satisfies.” The “science” of HVAC design is well developed. One has only to read the ASHRAE Handbook and other texts currently in use in the academic environment to realize that the basics of psychometrics, heat gain/loss calculations, fluid flow, fan and pump operations, and so on are well defined and readily available to the practicing engineer. Thus, while this text also addresses these fundamental topics, it is, rather, the “art” of successful HVAC design, including proper system and component application, which was incorporated into the first edition and significantly expanded in this second edition.
Design goes beyond load calculations and duct and pipe sizing. In fact, these are the smallest parts of the design effort. It is more important for the design engineer to have a proper grasp of systems applications, controls, and the basics of “fitting the right solution to solve the problem.” In this text, significant emphasis is placed on “systems” considerations of each basic topic. A word about units: In 1981, ASHRAE published their Handbook-Fundamentals in which the primary unit designations were in accordance with the Système International (SI).
The result was a handbook that was useless to the practicing professional in the United States, and there subsequently was a “revolt” within the membership of ASHRAE between the academic and practicing sides of the organization. The compromise was the publishing of xiii xiv Preface the 1985 Handbook-Fundamentals (and all subsequent volumes) in two separate editions, one using the inch-pound (IP) system and the other using SI. The first edition of this book, published in 1988, utilized only IP units. Since then, though, the HVAC market has become more global in nature and now ASHRAE requires dual unit publications.
Thus, this edition uses IP units and equations as primary, with SI units and equations as secondary, in accordance with the SI Guide for HVAC&R, American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. Now, 30 years since the first edition of this book was published, a number of HVAC topics have changed: heating/cooling load calculation methodologies, indoor air-quality considerations, control systems and sequences of operation, increased emphasis on energy efficiency and sustainability, etc.