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HVAC Design - Basics

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This pathway is the first step in an HVAC&R design professional’s learning beyond the structured academic environment. The sources are introductory in nature to assist those new to the industry as well as provide direction to others who simply want to improve their fundamental design knowledge and skills.

The resources identified under the HVAC Design pathway can contribute to the body of knowledge required for professionals seeking the Certified HVAC Designer (CHD) certification from ASHRAE.

Target Audience: New designers, contractors, and Manufacturer Representatives

  • eLearning

    eLearning provides a convenient and effective way to access on-demand web-based training at any time.

    Introduction to All-Air Systems (I-P), .5 PDHs
    This course explains the concept of all-air systems, with a focus on distribution and delivery components.

    HVAC System Selection Issues (I-P), 1.0 PDHs
    This course covers the process of selecting equipment to meet owner’s objectives and optimize system performance. 

    Air-Conditioning System Components – Heat transfer Equipment (I-P), 1.0 PDHs
    This course focuses on heat transfer equipment, which functions as a source component which help provide a primary heating or cooling effect for a system.

    Introduction to HVAC Design (I-P), 1.5 PDHs
    This course covers the scope and functions of modern HVAC systems and introduces the reader to the requirements of HVAC systems for maintaining human comfort in the built environment.

    Introduction to HVAC Design (SI), 1.5 PDHs
    This course covers the scope and functions of modern HVAC systems and introduces the reader to the requirements of HVAC systems for maintaining human comfort in the built environment.

    Air and Water Systems (I-P), 2.0 PDHs
    This course covers the applications, advantages, and disadvantages of air-and-water systems, as well as main component arrangement for maximum efficiency.

    Building Information Modeling (Dual), 2.0 PDHs
    Shows BIM's potential to improve the flow of data during planning, construction, and operations, as well as improve a building's lifetime sustainability.

    Multiple Zone Air Systems (I-P), 2.0 PDHs
    This course introduces systems to deal with situations where the instantaneous load varies from zone to zone.

    Multiple Zone Air Systems (SI), 2.0 PDHs
    This course introduces systems to deal with situations where the instantaneous load varies from zone to zone.

    The Design Process (I-P), 2.5 PDHs
    This course explains analysis and design. Covers design basics. Describes building codes, economics, other design factors.

    Air Systems (I-P), 2.5 PDHs
    This course package is comprised of 3 individual courses: Introduction to All-Air Systems, Dual-Duct and Multizone All-Air Systems, and Simple Rooftop All-Air Systems.

    Single Zone Air Handlers and Unitary Equipment (I-P), 3.0 PDHs
    This course covers calculation/ maintenance of mixed air temperature with Single-Zone Air Handlers and Refrigeration Equipment.

    Single Zone Air Handlers and Unitary Equipment (SI), 3.0 PDHs
    This course covers calculation/ maintenance of mixed air temperature with Single-Zone Air Handlers and Refrigeration Equipment.

    Loads and Modeling (I-P), 3.5 PDHs
    This course package is comprised of 2 individual courses: Building Information Modeling and Load Calculations.

    Introduction to HVAC Systems (Dual), 2.0 PDHs
    The course describes the basic vapor compression refrigeration cycle, and its components, and how it factors into the basic cooling portion of the typical heating, ventilating, and air-conditioning (HVAC) system.

    The Basics of Sustainable Design (I-P), 4.0 PDHs
    This course introduces key concepts of green design practices.

    Standard 90.1: Energy Standard for Buildings (I-P), 9.8 PDHs
    This course package is comprised of 4 individual courses: Standard 90.1-2004: Lighting – General and Mandatory Provisions; Standard 90.1-2004: Energy Cost Budget Method; Using Standard 90.1-2010 to Meet LEED Requirements; and Architects: Overview of Mechanical Systems.

    Hydronic Systems (I-P), 2.5 PDHs
    This course shows the components, strengths and weaknesses of hydronic systems and considerations for effective ventilation.

    Components and Equipment (I-P), 11.5 PDHs
    This course package is comprised of 6 individual courses: Air-Conditioning System Components: Heat Transfer Equipment; Air-Conditioning System Components: Pumps, Valves, Piping and Ductwork; Building Control; Introduction to Zones; Single Zone Air Handlers and Unitary Equipment; and Multiple Zone Air Systems.

    DDC Controls (I-P), 10.0 PDHs
    This course package is comprised of 3 individual courses: DDC Networks and Protocols; DDC Specification, Installation, and Commissioning; and DDC Introduction to Hardware and Software.

    DDC Controls (SI), 9.0 PDHs
    This course package is comprised of 2 individual courses: DDC Introduction to Hardware and Software; and DDC Specification, Installation, and Commissioning.

    HVAC Control Systems (I-P), 36.5 PDHs
    This course package is comprised of 9 individual courses: Introduction to HVAC Control Systems; Basics of Electricity; Control Valves and Dampers; Sensors and Auxiliary Devices; Self- and System-Powered Controls; Electric Controls; Pneumatic Controls; Control Diagrams and Sequences; and DDC Networks and Protocol.

    HVAC Control Systems (SI), 23.5 PDHs
    This course package is comprised of 5 individual courses: Basics of Electricity; Control Valves and Dampers; Control Diagrams and Sequences; DDC Introduction to Hardware and Software; and DDC Specification, Installation and Commissioning.

    Standard 62.1: Ventilation for Acceptable Air Quality (I-P), 10.1 PDHs
    This course package is comprised of 5 individual courses: Standard 62.1-2007: Natural Ventilation and Exhaust; Standard 62.1-2013: Natural Ventilation Procedure; Standard 62.1-2010 – Ventilation Rate Procedure; Standard 62.1-2007: Recirculating and Treating Indoor Air; and Standard 62.1-2007: Moisture and Mold Control.

    Fundamentals: HVAC Systems Library (I-P), 19.5 PDHs
    This course package is comprised of 9 individual courses: Introduction to HVAC Design; Introduction to HVAC Systems; Psychrometrics; Load Calculations; HVAC&R Controls; Humidity Control Design: Basic Principles, Loads and Equipment; Indoor Environmental Conditions for Human Comfort; Ventilation and IAQ; and Ethics for the Built Environment Professional Engineer.

    Fundamentals: HVAC Systems Library (SI), 18.5 PDHs
    This course package is comprised of 8 individual courses: Introduction to HVAC Systems; Thermal Comfort; Ventilation and IAQ; Introduction to Zones; Single Zone Air Handlers and Unitary Equipment; Multiple Zone Air Systems; Central Plants; and Introduction to HVAC Design.

    HVAC Systems Library (I-P), 36.0 PDHs
    This Library is comprised of 5 Course Packages: System Essentials; Air Systems; Hydronic Systems; Special Systems; and Electrical System Design.

    HVAC Design and Operation Library (I-P), 18.5 PDHs
    This Library is comprised of 3 Course Packages: Building Performance; System Design; and Loads and Modeling.

    Control Systems Library (I-P), 49.0 PDHs
    This Library is comprised of 2 Course Packages: HVAC Control Systems, and DDC Controls.

    Control Systems Library (SI), 32.5 PDHs
    This Library is comprised of 2 Course Packages: HVAC Control Systems, and D DC Controls.

  • Instructor-Led

    A wide range of live, instructor-led seminars, short courses and multi-day training is offered online and face-to-face. Check the courses below regularly for updated schedules.

    HVAC Design Training: Level I - Essentials (I-P), 18.0 PDHs
    This intensive, practical training provides a detailed understanding of HVAC fundamentals, equipment and systems.

    HVAC Design Training: Level II - Applications (I-P), 12.0 PDHs
    This training provides instruction in HVAC system design for experienced HVAC engineers and those who have completed HVAC Design: Level I – Essentials. It covers the technical aspects of design and allows participants an opportunity to expand their exposure to HVAC systems applications to increase energy savings and improve indoor environmental quality.

    Commissioning Process in New and Existing Buildings (I-P), 6.0 PDHs
    This introductory course focuses on how the building commissioning process can be applied cost-effectively to new construction and to existing facilities, with a strong emphasis on existing facilities applications.

    High-Performance Buildings Simplified: A Synopsis (I-P), 2.0 PDHs
    This course summarizes the core technical aspects of high-performance buildings (HPB). It is structured around the ASHRAE publication High-Performance Buildings Simplified: Designing, Constructing, and Operating Sustainable Commercial Buildings


  • SDLs

    Learn the basics from Self-Directed Learning texts. These provide flexible and affordable access to education and include skill development exercises to help evaluate your progress.

    Fundamentals of Air System Design (I-P & SI), 35.0 PDHs
    This course provides an understanding of the basics of air movement; the components of air distribution systems; considerations of human comfort; load and occupancy demand; duct system design; sound and vibration; and how codes and standards affect the design of air systems.

    Fundamentals of Design and Control of Central Chilled-Water Plants (I-P & SI), 35.0 PDHs
    This course provides tools and guidance to engineers so that the plants they design have a near optimum balance of first costs and future operating costs.

    Fundamentals of Heating and Cooling Loads (I-P), 35.0 PDHs
    This course provides an understanding of heat transfer as it applies to buildings and the various factors that must be considered when calculating the heating and cooling loads of a building.

    Fundamentals of Heating Systems (I-P), 35.0 PDHs
    This course provides an understanding of the various types of heating systems available for commercial and residential buildings and the three basic components of every heating system: the fuel source; the energy conversion plant; and the energy distribution system.

    Fundamentals of Psychrometrics (I-P & SI), 20.0 PDHs
    This course provides an understanding of the basic concepts of psychrometrics including moist air properties, evaporation, enthalpy, and temperature change, plus the basic HVAC processes.

    Fundamentals of Refrigeration (I-P & SI), 35.0 PDHs
    This course provides an understanding of the field of refrigeration, including the three main areas: comfort cooling or air conditioning; commercial refrigeration; and industrial refrigeration.

    Fundamentals of Steam System Design (I-P), 35.0 PDHs
    This course provides an understanding of the basic concepts of steam systems including terminology, properties of a system, analysis and design.

    Fundamentals of Thermodynamics (I-P & SI), 35.0 PDHs
    This course provides an understanding of the basic concepts of thermodynamic including properties of a system, processes and cycles, Ideal Gas Law, the laws of thermodynamics, refrigeration cycles and thermochemistry.

    Fundamentals of Water System Design (I-P & SI), 35.0 PDHs
    This course provides an understanding of the basic concepts of hydronic system operation and design including piping systems, pipe materials and fittings, centrifugal pumps, terminal units, expansion tanks and water chillers.

  • Publications

    ASHRAE Publications provide a great resource for reference, design guidance and learning. Publications are available in the ASHRAE Bookstore.

    Duct Size Calculator (I-P and SI)
    The Duct Size Calculator is intended for use as a quick reference tool for approximating duct sizes and equivalent sizes of sheet metal duct versus flexible duct. It includes sizing for metal ducts, and for flexible duct when compressed at 4%, 15%, and 30% straight line compression. One side of the wheel uses Inch-Pound (I-P) units; the other side uses International System (SI) units.

    HVAC Fast Facts I-P
    ASHRAE’s HVAC Fast Facts serves as a quick reference for commonly used HVAC acronyms, terminology, equations, and other essential information for designers, manufacturers, and engineers.

    Fundamentals of HVAC Systems (I-P)
    The Fundamentals of HVAC Systems is a thorough introduction on how HVAC systems control temperature, air quality, and air circulation in a conditioned space.

    Fundamentals of HVAC Systems (SI)
    The Fundamentals of HVAC Systems is a thorough introduction on how HVAC systems control temperature, air quality, and air circulation in a conditioned space.

    Air-Conditioning System Design Manual, 3rd ed
    Offering real-world applications in addition to theoretical calculations and analytical procedures, Air-Conditioning System Design Manual, Third Edition, bridges the gap between theory and practice in the design of HVAC&R systems. It has been completely revised and updated to reflect current industry best practices.

    Duct Systems Design Guide
    Duct Systems Design Guide gives engineers and other design professionals the tools to design properly sized duct systems to minimize fan energy consumption, system-generated noise, and the installed cost of ductwork.

    HVAC Simplified
    This text provides an understanding of fundamental HVAC concepts and how to extend these principles to the explanation of simple design tools used to create building systems that are efficient and provide comfortable and healthy environments.

    Principles of Heating, Ventilating, and Air Conditioning, 8th ed.
    Principles of Heating, Ventilating, and Air Conditioning is a textbook based on the 2017 ASHRAE Handbook--Fundamentals. It contains the most current ASHRAE procedures and definitive, yet easy to understand, treatment of building HVAC systems, from basic principles through design and operation.

  • Handbook
     View a complete list of chapters from the most recent four-volume series.

    The four-volume ASHRAE Handbook is a valuable reference. Each volume is revised on a four-year cycle, with one volume published each year. The volumes include: Fundamentals; Refrigeration; HVAC Applications; and HVAC Systems and Equipment.  Handbook chapters provide examples and guidance using best-practices principles. Chapters and full volumes are available in the ASHRAE Technology Portal and in the ASHRAE Bookstore.

    Below is a list of chapters from the Fundamentals Handbook and the HVAC Systems and Equipment Handbook which relate to the basics of HVAC design.



      Chapter 1. Psychrometrics
      Psychrometrics uses thermodynamic properties to analyze conditions and processes involving moist air and, as such, is a vital underlying concept for HVAC. This chapter discusses perfect gas relations and their use in common heating, cooling, and humidity control problems.

      Chapter 2. Thermodynamics and Refrigeration Cycles
      Thermodynamics, another fundamental concept for HVAC, examines energy, its transformations, and its relation to states of matter. This chapter covers thermodynamics applied to refrigeration cycles, methods for calculating thermodynamic properties, and compression and absorption refrigeration cycles.

      Chapter 3. Fluid Flow
      Flowing fluids in HVAC&R systems can transfer heat, mass, and momentum. This chapter introduces the basics of fluid mechanics related to HVAC processes, reviews pertinent flow processes, and presents a general discussion of single-phase fluid flow analysis.

      Chapter 4. Heat Transfer
      This chapter presents elementary principles of single-phase heat transfer, with emphasis on HVAC applications.

      Chapter 5. Two-Phase Flow
      This chapter introduces two-phase flow and heat transfer processes of pure substances and refrigerant mixtures.

      Chapter 6. Mass Transfer
      This chapter addresses mass transfer principles and provides methods of solving a simultaneous heat and mass transfer problem involving air and water vapor, emphasizing air-conditioning processes.

      Chapter 7. Fundamentals of Control
      This chapter focuses on the fundamental concepts and devices normally used by a control system designer. It covers (1) control fundamentals, including terminology; (2) types of control components; (3) methods of connecting components to form various individual control loops, subsystems, or networks; and (4) commissioning and operation.

      Chapter 8. Sound and Vibration
      If fundamental principles of sound and vibration control are applied in the design, installation, and use of HVAC&R systems, suitable levels of noise and vibration can be achieved with a high probability of user acceptance. This chapter introduces these fundamental principles, including characteristics of sound, basic definitions and terminology, human response to sound, acoustic design goals, and vibration isolation fundamentals.


      Chapter 9. Thermal Comfort
      This chapter summarizes the fundamentals of human thermoregulation and comfort in terms useful to the engineer for operating systems and designing for the comfort and health of building occupants.

      Chapter 10. Indoor Environmental Health
      This chapter provides general background information and introduces important concepts of hazard recognition, analysis, and control. It also presents information on specific hazards, and describes sources of exposure to each hazard, potential health effects, relevant exposure standards and guidelines, and methods to control exposure. This chapter also includes a brief introduction to the very broad and dynamic field of indoor environmental health.


      Chapter 14. Climatic Design Information
      This chapter and the accompanying data summaries in PDF format provide the climatic design information for 9237 locations in the United States, Canada, and around the world.

      Chapter 16. Ventilation and Infiltration
      This chapter addresses commercial and institutional buildings, where ventilation concerns usually dominate (though infiltration should not be ignored), and single- and multifamily residences, where infiltration has always been considered important but ventilation issues have received increased attention in recent years.

      Chapter 17. Residential Cooling and Heating Load Calculations
      This chapter covers cooling and heating load calculation procedures for residential buildings, including detailed heat-balance methods that serve as the basis for cooling load calculation. Simple cooling load procedures, suitable for hand calculations, are provided for typical cases. Straightforward heating load calculation procedures are also included.

      Chapter 18. Nonresidential Cooling and Heating Load Calculations
      This chapter discusses common elements of cooling load calculation (e.g., internal heat gain, ventilation and infiltration, moisture migration, fenestration heat gain) and two methods of heating and cooling load estimation: heat balance (HB) and radiant time series (RTS).


      Chapter 20. Space Air Diffusion
      Room air distribution systems are intended to provide thermal comfort and ventilation for space occupants and processes. Although air terminals (inlets and outlets), terminal units, local ducts, and rooms themselves may affect room air diffusion, this chapter addresses only air terminals and their direct effect on occupant comfort.

      Chapter 21. Duct Design
      In this chapter, system design and calculation of a system’s frictional and dynamic resistance (total pressure) to airflow are considered.

      Chapter 22. Pipe Design
      This chapter discusses pipe systems, materials, design, installation, supports, stress calculations, pipe expansion and flexibility, bends and loops, and application of pipe systems commonly used for heating, air conditioning, refrigeration, and service water.

      Chapter 23. Insulation for Mechanical Systems
      This chapter deals with applications of thermal and acoustical insulation for mechanical systems in residential, commercial, and industrial facilities. Applications include pipes, tanks, vessels and equipment, and ducts.

      Chapter 24. Airflow Around Buildings
      This chapter deals with applications of thermal and acoustical insulation for mechanical systems in residential, commercial, and industrial facilities. Applications include pipes, tanks, vessels and equipment, and ducts.


      Chapter 39. Abbreviations and Symbols
      This chapter contains information about abbreviations and symbols for HVAC&R engineers.

      Chapter 40. Units and Conversions
      This chapter gives conversion factors for important and commonly used I-P and SI units.

      Chapter 41. Codes and Standards
      This chapter lists important codes and standards from a broad spectrum of engineering societies and provides contact information for the issuing organizations.



      Chapter 1. HVAC System Analysis and Selection
      This chapter addresses procedures for selecting an appropriate system for a given application while taking into account pertinent issues associated with designing, building, commissioning, operating, and maintaining the system.

      Chapter 2. Decentralized Cooling and Heating
      Frequently classified as packaged unit systems (although many are far from being a single packaged unit), decentralized systems can be found in almost all classes of buildings. Although some of the equipment addressed here can be applied as a single unit, this chapter covers applying multiple units to form a complete heating and air-conditioning system for a building and the distribution associated with some of these systems.

      Chapter 3. Central Cooling and Heating Plants
      This chapter addresses design alternatives that should be considered when centralizing a facility’s cooling and heating sources.

      Chapter 4. Air Handling and Distribution
      Very early in the design of a new or retrofit building project, the HVAC design engineer must analyze and ultimately select the basic systems and whether production of primary heating and cooling should be decentralized or central. This chapter covers the options, processes, available equipment, and challenges of all-air systems,

      Chapter 5. In-Room Terminal Systems
      Very early in the design process, the HVAC design engineer must analyze and ultimately select appropriate systems. Next, production of heating and cooling is selected as decentralized or centralized. Finally, distribution of heating and cooling to the end-use space can be done by an all-air system or a variety of all-water or air/water systems and local terminals, as discussed in this chapter.

      Chapter 6. Radiant Heating and Cooling
      Panel heating and cooling systems use temperature-controlled indoor surfaces on the floor, walls, or ceiling; temperature is maintained by circulating water, air, or electric current through a circuit embedded in or attached to the panel. This chapter covers temperature-controlled surfaces that are the primary source of sensible heating and cooling in the conditioned space.

      Chapter 7. Combined Heat and Power Systems
      This chapter describes the increasing role of combined heat and power (CHP) in sustainable design strategies, presents typical system designs, provides means and methods to understand system performance, and describes prime movers, such as reciprocating and Stirling engines, combustion and steam turbines, and fuel cells, and their characteristics for various uses.

      Chapter 8. Combustion Turbine Inlet Cooling
      This chapter provides a detailed discussion on combustion turbine inlet cooling (CTIC).
      Chapter 9. Applied Heat Pump and Heat Recovery Systems
      A heat pump extracts heat from a source and transfers it to a sink at a higher temperature. According to this definition, all pieces of refrigeration equipment, including air conditioners and chillers with refrigeration cycles, are heat pumps. In engineering, however, the term heat pump is generally reserved for equipment that heats for beneficial purposes, rather than that which removes heat for cooling only. Dual-mode heat pumps alternately provide heating or cooling. Heat reclaim heat pumps provide heating only, or simultaneous heating and cooling. An applied heat pump requires competent field engineering for the specific application, in contrast to the use of a manufacturer-designed unitary product…

      Chapter 10. Small Forced-Air Heating and Cooling Systems
      This chapter describes the basics of design and component selection of small forced-air heating and cooling systems, explains their importance, and describes the system’s parametric effects on energy consumption. It also gives an overview of test methods for thermal distribution system efficiency and considers the interaction between the building thermal/pressure envelope and the forced-air heating and cooling system, which is critical to the energy efficiency and cost-effectiveness of the overall system. This chapter pertains to residential and certain small commercial systems; large commercial systems are beyond the scope of this chapter.

      Chapter 11. Steam Systems
      Steam systems use the vapor phase of water to supply heat or kinetic energy through a piping system. As a source of heat, steam can heat a conditioned space with suitable terminal heat transfer equipment such as fan-coil units, unit heaters, radiators, and convectors (finned tube or cast iron), or through a heat exchanger that supplies hot water or some other heat transfer medium to the terminal units. In addition, steam is commonly used in heat exchangers (shell-and-tube, plate, or coil types) to heat domestic hot water and supply heat for industrial and commercial processes such as in laundries and kitchens. Steam is also used as a heat source for certain cooling processes such as single-stage and two-stage absorption refrigeration machines.

      Chapter 12. District Heating and Cooling
      District heating and cooling (DHC) or district energy (DE) distributes thermal energy from a central source to residential, commercial, and/or industrial consumers for use in space heating, cooling, water heating, and/or process heating. The energy is distributed by steam or hot- or chilled-water lines. Thus, thermal energy comes from a distribution medium rather than being generated onsite at each facility.

      Chapter 13. Hydronic Heating and Cooling
      This chapter describes forced recirculating systems. Successful water system design depends on awareness of the many complex interrelationships between various elements. In a practical sense, no component can be selected without considering its effect on the other elements.

      Chapter 14. Condenser Water Systems
      As part of the vapor-compression cycle for mechanical refrigeration, the heat of compression produced must be rejected to complete the refrigeration cycle. Refrigerant systems may be cooled by air or water. In water-cooled systems, water flows through the condenser and is called condenser water. Condenser water systems are classified as (1) once-through systems (e.g., city water, well-water, or lake/groundwater systems), or (2) recirculating or cooling tower systems. This chapter focuses on open condenser water systems and evaporative coolers.

      Chapter 15. Medium- and High-Temperature Water Heating
      Medium-temperature water (MTW) systems have operating temperatures ranging from 250°F to 350°F (120 to 175°C) and are designed to a pressure rating of 125 to 150 psig (860 to 1030 kPa [gage]). High-temperature water (HTW) systems are classified as those operating with supply water temperatures above 350°F (175°C) and designed to a pressure rating of 300 psig (2000 kPa [gage]). The usual practical temperature limit is about 450°F (230°C) because of pressure limitations on pipe fittings, equipment, and accessories. The rapid pressure rise that occurs as the temperature rises above 450°F (230°C) increases cost because components rated for higher pressures are required. The design principles for both medium- and high-temperature systems are basically the same. This chapter presents the general principles and practices that apply to MTW/HTW systems and distinguishes them from low-temperature water systems operating below 250°F (120°C).

      Chapter 16. Infrared Radiant Heating
      Infrared radiant heating principles discussed in this chapter apply to equipment with thermal radiation source temperatures ranging from 300 to 5000°F (150 to 2760°C).

      Chapter 17. Ultraviolet Lamp Systems
      This chapter includes a review of the fundamentals of UV-C energy’s impact on microorganisms; how UV-C lamps generate germicidal radiant energy; various components that comprise UV-C devices and systems; and a review of human safety and maintenance issues.

      Chapter 18. Variable Refrigerant Flow
      Variable-refrigerant-flow (VRF) HVAC systems are a direct-expansion (DX) heat pump technology platform built on the standard reverse Rankine vapor compression cycle. These systems are thermodynamically similar to unitary and other common DX systems, and share many of the same components (i.e., compressor, expansion device, heat exchangers). VRF systems transport heat between an outdoor condensing unit and a network of indoor units located near or within the conditioned space through refrigerant piping installed in the building. Attributes that distinguish VRF from other DX system types are multiple indoor units connected to a common outdoor unit (single or combined modules), scalability, variable capacity, distributed control, and simultaneous heating and cooling.


      Chapter 19. Duct Construction
      This chapter covers construction of HVAC and exhaust duct systems for residential, commercial, and industrial applications.

      Chapter 20. Room Air Distribution Equipment
      This chapter describes room air distribution equipment, details its proper use, and is intended to help HVAC designers select the equipment applicable to outlined air distribution methods.

      Chapter 21. Fans
      A fan uses a power-driven rotating impeller to move air. The impeller does work on the air, imparting to it both static and kinetic energy, which vary in proportion, depending on the fan type. This chapter discusses types of fans used in HVAC design and the underlying principles of their use.

      Chapter 22. Humidifiers
      In the selection and application of humidifiers, the designer considers (1) the environmental conditions of the occupancy or process and (2) the characteristics of the building enclosure. Because these may not always be compatible, compromise is sometimes necessary, particularly in the case of existing buildings.

      Chapter 23. Air-Cooling and Dehumidifying Coils
      This chapter discusses uses, selection, performance, and maintenance of air-cooling and dehumidifying coils.

      Chapter 24. Desiccant Dehumidification and Pressure-Drying Equipment
      This chapter covers (1) the types of dehumidification equipment for liquid and solid desiccants, including high-pressure equipment;(2) performance curves; (3) variables of operation; and (4) some typical applications.

      Chapter 25. Mechanical Dehumidifiers and Related Components
      The correct moisture level in the air is important for health and comfort. Controlling humidity and condensation is important to prevent moisture damage and mold or mildew development, thus protecting buildings and occupants, and preserving building contents This chapter covers mechanical dehumidification using a cooling process only, including basic dehumidifier models (with moisture removal capacity of less than 3 lb/h [1.4 kg/h]) used for home basements and small storage areas, as well as larger sizes required for commercial applications.

      Chapter 26. Air-to-Air Energy Recovery Equipment
      Air-to-air energy recovery is the process of recovering heat or/and moisture between two airstreams at different temperatures and humidities. This process is important in maintaining acceptable indoor air quality (IAQ) while maintaining low energy costs and reducing overall energy consumption. This chapter describes various technologies for air-to-air energy recovery. Thermal and economic performance, maintenance, and related operational issues are presented, with emphasis on energy recovery for ventilation.

      Chapter 27. Air-Heating Coils
      Air-heating coils are used to heat air under forced convection. The total coil surface may consist of a single coil section or several coil sections assembled into a bank. The coils described in this chapter apply primarily to comfort heating and air conditioning using steam, hot water, refrigerant vapor heat reclaim (including heat pumps), and electricity. The choice between the various methods of heating depends greatly on the cost of the various available energy sources. For instance, in areas where electric power is cheaply available and heating requirements are limited, heat pumps are a very viable option. With available power and higher heat requirements, electric heat is used. If electric power is considerably expensive, steam or hot water generated using gas-fired sources is used in larger buildings and district cooling.

      Chapter 28. Unit Ventilators, Unit Heaters, and Makeup Air Units
      This chapter discusses unit ventilators, unit heaters, and makeup air units and how they are deployed in HVAC systems.

      Chapter 29. Air Cleaners for Particulate Contaminants
      This chapter discusses removal of contaminants from both ventilation and recirculated air used for conditioning building interiors. Complete air cleaning may require removing of airborne particles, microorganisms, and gaseous contaminants, but this chapter only covers removal of airborne particles and briefly discusses bioaerosols.

      Chapter 30. Industrial Gas Cleaning and Air Pollution Control
      Equipment that removes particulate matter from a gas stream may also remove or create some gaseous contaminants; on the other hand, equipment that is primarily intended for removal of gaseous pollutants might also remove or create objectionable particulate matter to some degree. In all cases, gas-cleaning equipment changes the process stream, and it is therefore essential that the engineer evaluate the consequences of those changes to the plant’s overall operation. In this chapter, each generic type of equipment is discussed on the basis of its primary method for gas or particulate abatement. The development of systems that incorporate several of the devices discussed here for specific industrial processes is left to the engineer.


      Chapter 31. Automatic Fuel-Burning Systems
      This chapter covers the design and use of automatic fuel-burning systems. The fuel can be gaseous (e.g., natural or liquefied petroleum gas), liquid (primarily the lighter grades of fuel oil or biodiesel), or solid (e.g., coal, or renewable items such as wood or corn).

      Chapter 32. Boilers
      Excluding special and unusual fluids, materials, and methods, a boiler is a cast-iron, carbon or stainless steel, aluminum, or copper pressure vessel heat exchanger designed to (1) burn fossil fuels (or use electric current) and (2) transfer the released heat to water (in water boilers) or to water and steam (in steam boilers). Boiler heating surface is the area of fluid-backed surface exposed to the products of combustion, or the fire-side surface. Various manufacturers define allowable heat transfer rates in terms of heating surface based on their specific boiler design and material limitations. Boiler designs provide for connections to a piping system, which delivers heated fluid to the point of use and returns the cooled fluid to the boiler.

      Chapter 33. Furnaces
      Furnaces are self-enclosed, permanently installed major appliances that provide heated air through ductwork to the space being heated. In addition, a furnace may provide the indoor fan necessary for circulating heated or cooled air from a split or single-package air conditioner or heat pump.

      Chapter 34. Residential In-Space Heating Equipment
      In-space heating equipment differs from central heating in that fuel is converted to heat in the space to be heated. In-space heaters may be either permanently installed or portable and may transfer heat by a combination of radiation, natural convection, and forced convection. The energy source may be liquid, solid, gaseous, or electric.

      Chapter 35. Chimney, Vent, and Fireplace Systems
      A properly designed chimney or vent system provides and controls draft to convey flue gas from an appliance to the outdoors. This chapter describes the design of chimneys and vent systems that discharge flue gas from appliances and fireplace systems.

      Chapter 36. Hydronic Heat-Distributing Units and Radiators
      Radiators, convectors, and baseboard and finned-tube units are heat-distributing devices used in hot-water and steam heating systems. They supply heat by a combination of radiation and convection and maintain the desired air temperature and/or mean radiant temperature in a space without fans. In heating systems, radiant panels are also used. Units are inherently self-adjusting in the sense that heat output is based on temperature differentials; cold spaces receive more heat and warmer spaces receive less heat.

      Chapter 37. Solar Energy Equipment
      Solar energy use is becoming more economical as the cost of energy continues to climb, especially with increasing government and utility incentives as well as growing interest in green and/or sustainable construction. In addition, many countries consider solar and renewable energy as a security measure to ensure the availability of power under adverse conditions. While the United States continues to grow its solar industry, China, Europe, Asia, and the Mediterranean basin are leading development of advanced manufacturing techniques and applications. However, equipment and systems are still very similar in all markets; therefore, this chapter primarily discusses the basic equipment used, with particular attention to collectors.


      Chapter 38. Compressors
      A compressor is one of the four essential components of the basic vapor compression refrigeration system; the others are the condenser, evaporator, and expansion device. The compressor circulates refrigerant through the system and increases refrigerant vapor pressure to create the pressure differential between the condenser and evaporator. This chapter describes the design features of several categories of commercially available refrigerant compressors.

      Chapter 39. Condensers
      Condensers may be classified by their cooling medium as (l) water-cooled, (2) air-cooled, (3) evaporative (air- and water-cooled), and (4) refrigerant-cooled (cascade systems). The first three types are discussed in this chapter.

      Chapter 40. Cooling Towers
      Most air-conditioning systems and industrial processes generate heat that must be removed and dissipated. Water is commonly used as a heat transfer medium to remove heat from refrigerant condensers or industrial process heat exchangers. In the past, this was accomplished by drawing a continuous stream of water from a utility water supply or a natural body of water, heating it as it passed through the process, and then discharging the water directly to a sewer or returning it to the body of water. Water purchased from utilities for this purpose has become prohibitively expensive because of increased water supply and disposal costs. Similarly, cooling water drawn from natural sources is relatively unavailable because the ecological disturbance caused by the increased temperature of discharge water has become unacceptable.

      Chapter 41. Evaporative Air-Cooling Equipment
      This chapter addresses direct and indirect evaporative equipment, air washers, and their associated equipment used for air cooling, humidification, dehumidification, and air cleaning.

      Chapter 42. Liquid Coolers
      A liquid cooler (hereafter called a cooler) is a heat exchanger in which refrigerant is evaporated, thereby cooling a fluid (usually water or brine) circulating through the cooler. This chapter addresses the performance, design, and application of coolers.

      Chapter 43. Liquid-Chilling Systems
      Liquid-chilling systems cool water, brine, or other secondary coolant for air conditioning or refrigeration. The chiller maybe either factory-assembled and wired or shipped in sections for erection in the field. The most frequent application is water chilling for air conditioning, although brine cooling for low-temperature refrigeration and chilling fluids in industrial processes are also common.


      Chapter 44. Centrifugal Pumps
      Centrifugal pumps provide the primary force to distribute and recirculate hot and chilled water in a variety of space-conditioning and plumbing systems. The pump provides a predetermined flow of water to the space load terminal units or to a thermal storage chamber for release at peak loads.

      Chapter 45. Motors, Motor Controls, and Variable-Frequency Drives
      Many types of alternating-current (AC) motors are available; direct-current (DC) motors are also used, but to a more limited degree. National Electrical Manufacturers Association (NEMA) Standard MG 1 provides technical information on most types of AC and DC motors.

      Chapter 46. Valves
      Valves are the manual or automatic fluid-controlling elements in a piping system. They are constructed to withstand a specific range of temperature, pressure, corrosion, and mechanical stress. The designer selects and specifies the proper valve for the application to give the best service for the economic requirements.

      Chapter 47. Heat Exchangers
      This chapter describes some of the fundamentals, types, components, applications, selection criteria, and installation of heat exchangers.


      Chapter 48. Unitary Air Conditioners and Heat Pumps
      Unitary air conditioners are factory-made assemblies that normally include an evaporator or cooling coil and a compressor/condenser combination, and possibly provide heating as well. An air-source unitary heat pump normally includes an indoor conditioning coil, compressor(s), and an outdoor coil. It must provide heating and possibly cooling as well. A water-source heat pump rejects or extracts heat to and from a water loop instead of from ambient air. A unitary air conditioner or heat pump with more than one factory-made assembly (e.g., indoor and outdoor units) is commonly called a split system.

      Chapter 49. Room Air Conditioners and Packaged Terminal Air Conditioners
      Room air conditioners are encased assemblies designed primarily for mounting in a window or through a wall. They are designed to deliver cool or warm conditioned air to the room, either without ducts or with very short ducts (up to a maximum of about 48 in. [1220 mm]). Each unit includes a prime source of refrigeration and dehumidification and a means for circulating and filtering air; it may also include a means for ventilating and/or exhausting and heating. PTACs are designed primarily for commercial installations to provide the total heating and cooling functions for a room or zone and are specifically for through-the-wall installation. The units are mostly used in relatively small zones on the perimeter of buildings such as hotels and motels, apartments, hospitals, nursing homes, and office buildings. In larger buildings, they may be combined with nearly any system selected for environmental control of the building core. This chapter discusses design and application of both types of systems.



      Chapter 1. Halocarbon Refrigeration Systems
      This chapter focuses on systems that use halocarbons (halogenated hydrocarbons) as refrigerants. The most commonly used halogen refrigerants are chlorine (Cl) and fluorine (F). Halocarbon refrigerants are classified into four groups: chlorofluorocarbons (CFCs), which contain carbon, chlorine, and fluorine; hydrochlorofluorocarbons (HCFCs), which consist of carbon, hydrogen, chlorine, and fluorine; hydrofluorocarbons (HFCs), which contain carbon, hydrogen, and fluorine; and hydrofluoroolefins (HFOs), which are HFC refrigerants derived from an alkene (olefin; i.e., an unsaturated compound having at least one carbon-to-carbon double bond).

      Chapter 2. Ammonia Refrigeration Systems
      Ammonia is the refrigerant of choice for many industrial refrigeration systems. Custom-engineered ammonia (R-717) refrigeration systems often have design conditions that span a wide range of evaporating and condensing temperatures. Examples are (1) a food freezing plant operating from +50 to –50°F (10 to –45°C); (2) a candy storage requiring 60°F (15°C) db with precise humidity control; (3) a beef chill room at 28 to 30°F (–2 to –1°C) with high humidity; (4) a distribution warehouse requiring multiple temperatures for storing ice cream, frozen food, meat, and produce and for docks; and (5) a chemical process requiring multiple temperatures ranging from +60 to –60°F (15 to –50°C).

      Chapter 3. Carbon Dioxide Refrigeration Systems
      Carbon dioxide (R-744) is one of the naturally occurring compounds collectively known as “natural refrigerants.” It is nonflammable and nontoxic, with no known carcinogenic, mutagenic, or other toxic effects, and no dangerous products of combustion. Using carbon dioxide in refrigerating systems can be considered a form of carbon capture, with a potential beneficial effect on climate change. It has no adverse local environmental effects. In recent years, CO2 has once again become a refrigerant of great interest. However, high-pressure CO2 systems [e.g., 490.8 psia (3.4 MPa) at a saturation temperature of 30°F (–1°C), or 969.6 psia (6.7 MPa) at 80°F (26.7°C)] present some challenges for containment and safety.

      Chapter 4. Liquid Overfeed Systems
      Overfeed systems force liquid in excess of the amount evaporated, either mechanically or by gas pressure, through organized-flow evaporators, separate it from the vapor, and return it to the evaporators. Mechanically pumped systems usually pump from a vessel at the connected suction pressure (i.e., low-temperature liquid). Gas-operated systems can be configured to deliver either low-temperature liquid directly like the mechanically pumped system, or subcooled liquid from a controlled pressure receiver at an intermediate pressure. With the latter, the accumulated overfed liquid is transferred from the low-pressure receiver back to the controlled-pressure receiver.

      Chapter 5. Component Balancing in Refrigeration Systems
      This chapter describes methods and components used in balancing a primary refrigeration system. A refrigerant is a fluid used for heat transfer in a refrigeration system. The fluid absorbs heat at a low temperature and pressure and transfers heat at a higher temperature and pressure. Heat transfer can involve either a complete or partial change of state in the case of a primary refrigerant. Energy transfer is a function of the heat transfer coefficients; temperature differences; and amount, type, and configuration of the heat transfer surface and, hence, the heat flux on either side of the heat transfer device.

      Chapter 6. Refrigerant System Chemistry
      This chapter covers the chemical aspects of refrigerants and lubricants, and their compatibility with each other as well as with system materials. Two distinct chemical evaluations are generally undertaken when considering new refrigerant or lubricant candidates: (1) chemical compatibility testing to assess the stability of refrigerant and lubricant with each other and with system components, and (2) material compatibility testing to assess the stability of system component materials with refrigerant and/or lubricant.

      Chapter 7. Control of Moisture and Other Contaminants in Refrigerant Systems
      Moisture (water) is an important and universal contaminant in refrigeration systems. The amount of moisture in a refrigerant system must be kept below an allowable maximum for satisfactory operation, efficiency, and longevity. Moisture must be removed from components during manufacture, assembly, and service to minimize the amount of moisture in the completed system. Any moisture that enters during installation or servicing should be removed promptly. Refrigerant filter-driers are the principal devices used to remove contaminants from refrigeration systems. The filter-drier is not a substitute for good workmanship or design, but a maintenance tool necessary for continued and proper system performance. Contaminants removed by filter-driers include moisture, acids, hydrocarbons with a high molecular weight, oil decomposition products, and insoluble material, such as metallic particles and copper oxide.

      Chapter 8. Equipment and System Dehydrating, Charging, and Testing
      Proper dehydration, charging, and testing of packaged refrigeration systems and components (compressors, evaporators, and condensing coils) help ensure proper performance and extend the life of refrigeration systems. This chapter covers the methods used to perform these functions. It does not address criteria such as allowable moisture content, refrigerant quantity, and performance, which are specific to each machine.

      Chapter 9. Refrigerant Containment, Recovery, Recycling, and Reclamation
      Containment of refrigerant is an important consideration during installation, service, maintenance, and decommissioning of refrigeration systems. The potential environmental effect of chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants on ozone depletion, and of these and the hydrofluorocarbon (HFC) and hydrofluoroolefin (HFO) refrigerants on global warming, make it imperative that refrigerants are confined to closed systems and recovered during service and at the end of life. Containment must be considered in all phases of a system’s life, including (1) design and construction of leaktight and easily serviced systems, (2) leak detection and repair, (3) recovery during service, and (4) recovery at system disposal.


      Chapter 10. Insulation Systems for Refrigerant Piping
      This chapter is a guide to specifying insulation systems for refrigeration piping, fittings, and vessels operated at temperatures ranging from 35 to –100°F (2 to –70°C). It does not deal with HVAC systems or applications such as chilled-water systems.

      Chapter 11. Refrigerant Control Devices
      Control of refrigerant flow, temperatures, pressures, and liquid levels is essential in any refrigeration system. This chapter describes a variety of devices and their application to accomplish these important control functions. Most examples, references, and capacity data in this chapter refer to the more common refrigerants.

      Chapter 12. Lubricants in Refrigerant Systems
      The primary function of a lubricant is to reduce friction and minimize wear. It achieves this by interposing a film between moving surfaces that reduces direct solid-to-solid contact or lowers the coefficient of friction. Understanding the role of a lubricant requires analysis of the surfaces to be lubricated. Although bearing surfaces and other machined parts may appear and feel smooth, close examination reveals microscopic peaks (asperities) and valleys. Lubricant, in sufficient amounts, creates a layer thicker than the maximum height of the mating asperities, so that moving parts ride on a lubricant cushion.

      Chapter 13. Secondary Coolants in Refrigeration Systems
      Secondary coolants are liquids used as heat transfer fluids that change temperature as they gain or lose heat energy without changing into another phase. For lower refrigeration temperatures, this requires a coolant with a freezing point below that of water. These are generally called brines by the industry. This chapter discusses design considerations for components, system performance requirements, and applications for secondary coolants.

      Chapter 14. Forced-Circulation Air Coolers
      Forced-circulation unit coolers and product coolers are designed to operate continuously in refrigerated enclosures; a cooling coil and motor-driven fan are their basic components, and provide cooling or freezing temperatures and proper airflow to the room. Coil defrost equipment is added for low-temperature operations when coil frosting might impede performance. Any unit (e.g., blower coil, unit cooler, product cooler, cold diffuser unit, air-conditioning air handler) is considered a forced-air cooler when operated under refrigeration conditions.

      Chapter 15. Retail Food Store Refrigeration and Equipment
      In the United States, over 227,000 retail food stores operate their refrigeration systems around the clock to ensure proper merchandising and safety of their food products. Supermarkets and convenience stores make the largest contribution to this total (Progressive Grocer 2017). In U.S. retail food stores, refrigeration consumes about 2.3% of the total electricity consumed by all commercial buildings (EIA 2003). Refrigeration accounts for roughly 50% of the electric energy consumption of a typical supermarket (Arthur D. Little 1996).

      Chapter 16. Food Service and General Commercial Refrigeration Equipment
      Food service requires refrigerators that meet a variety of needs. This chapter covers refrigerators available for restaurants, fast-food restaurants, cafeterias, commissaries, hospitals, schools, convenience stores, grocery stores, and other specialized applications. Many refrigeration products used in food service applications are self-contained, and the corresponding refrigeration systems are conventional. Some systems, however, do use ice for fish, salad pans, or specialized preservation and/or display. Chapters 15 and 17 have further information on some of these products.

      Chapter 17. Household Refrigerators and Freezers
      This chapter covers design and construction of household refrigerators and freezers. Providing optimized conditions for preserving stored food is the primary function of a refrigerator or freezer. This is done by storing food at reduced temperature. Ice making is an essential secondary function in some markets. A related product, the wine chiller, provides optimum temperatures for storing wine, at temperatures from 45 to 65°F (7 to 18°C). Wine chillers are often manufactured by the same companies using the same technologies as refrigerators and freezers. Dual-use products combining a wine storage compartment with fresh-food and/or freezer compartments have also been manufactured.

      Chapter 18. Absorption Equipment
      This chapter surveys and summarizes the types of absorption equipment that are currently manufactured and/or commonly encountered. The equipment can be broadly categorized by whether it uses water or ammonia as refrigerant. The primary products in the water refrigerant category are large commercial chillers, which use lithium bromide (LiBr) as absorbent. There are three primary products in the ammonia refrigerant category: (1) domestic refrigerators, (2) residential chillers, and (3) industrial refrigeration units.


      Chapter 50. Terminology of Refrigeration
      This chapter seeks to define some of the common terms used in industrial refrigeration systems, specifically those using ammonia as the refrigerant. The following glossary was compiled from a variety of sources throughout the industry, including ASHRAE, the International Institute of Ammonia Refrigeration (IIAR), the U.S. Occupational Safety and Health Administration (OSHA), and the U.S. Environmental Protection Agency (EPA). Specific sources for entries are listed in the endnotes. Minor edits for punctuation, conciseness, and consistency with usage elsewhere in the Handbook have been made.

      Chapter 51. Codes and Standards
      This chapter lists important codes and standards from a broad spectrum of engineering societies, and provides contact information for the issuing organizations.

  • Journal Articles

    Over 1,700+ ASHRAE Journal articles are available in the ASHRAE Technology Portal (Free to ASHRAE Members). Journal columns, including Engineers Notebook, Refrigeration Applications and Building Sciences are also included. Below is a sample of articles directly related to the basics of HVAC Design.

    What to Consider When Designing for N+1, Engineers Notebook, ASHRAE Journal, November 2020
    Author shares lessons learned when he was a system owner at a silicon wafer fabrication plant.

    Jargon Buster, Refrigeration Applications, ASHRAE Journal, December 2012
    Author briefly defines some common refrigeration terms.

    Understanding Walls, Building Sciences, ASHRAE Journal, June 2020
    The most common examples for wall control layers and control approaches for wood frame and concrete masonry unit assemblies.

    Learning to Use Architectural Acoustics in Engineering, Engineers Notebook, ASHRAE Journal, January 2021
    This column introduces how room functionality improves with improved architectural acoustics, especially in rooms used for collaboration, instruction and assembly where clear speech is needed.

    The Fundamentals of Expansion Tanks, ASHRAE Journal, November 2016
    Who would have thought such a simple piece of equipment, the expansion tank, could be so misunderstood? Author clears up some of the issues and provide simples advice for expansion tank sizing and piping.

    Designing Air-Distribution Systems to Maximize Comfort, ASHRAE Journal, September 2012
    An air-distribution system can be successfully designed by understanding what makes us comfortable and selecting the proper air-distribution products and layout.

    VAV Terminal Units: Looking Back, Ahead: System Components, ASHRAE Journal, October 2015
    This Fundamentals at Work article explores commercial building variable air volume (VAV) terminal units. It includes discussion of the evolution of terminal units, benefits of different components, and research on energy consumption and standards.

    Thermal Comfort: Designing for People, ASHRAE Journal, February 2018
    Thermal environmental quality is fundamental for human occupancy. This article focuses on raising awareness of thermal comfort analyses and standards that help optimize people’s environments.

    Energy Modeling Basics, ASHRAE Journal, December 2012
    Making a precise energy model capable of estimating the building's energy use is difficult because of the assumptions that have to be made and evaluated through the modeling process. So, learning about energy modeling means more than simply constructing or reconstructing a building in a software program. It means being familiar with ASHRAE and other resources, and working with the HVAC engineer and designer, to make good assumptions that result in an accurate energy model.

    Methods for Effective Room Air Distribution: Part 1, ASHRAE Journal, November 2012
    Before applying new air-distribution technology solutions, it's important to understand the basics. This article discusses essential requirements (in standards, guidelines and rating systems) that cover thermal comfort, acoustics and ventilation, and what's involved in properly applying them to the typical main delivery systems.

    Methods for Effective Room Air Distribution: Part 2, ASHRAE Journal, December 2012
    Before applying new air-distribution technology solutions, it's important to understand the basics. This article discusses air delivery systems, including overhead well-mixed systems, underfloor partially stratified systems, and displacement fully stratified systems.

    Part One: Radiant Heating and Cooling Systems, ASHRAE Journal, February 2015
    This two-part article describes basic knowledge of radiant heating and cooling systems to give a principle understanding of the design and operation of this advantageous system including comfort, system load, heating/cooling capacity, installation and application of the system with examples.

    Hydronics 101, ASHRAE Journal, May 2015
    Hydronic systems provide large amounts of heat transfer with low first costs and energy costs for transporting energy. This article provides only a basic overview and introduction to hydronic system design, layout and components. Today, hydronic heating and cooling coils are frequently used in conjunction with forced air systems. More recently there has been a resurgence of hydronic applications at the zone level as a result of the increased emphasis on energy conservation.

    Hydronics 102: System Components, ASHRAE Journal, September 2015
    This article provides an overview of two common control devices in closed loop hydronic systems: expansion tanks and valves. Expansion tanks manage expansion as water temperature increases and control system pressure. Valves serve everything from the basic function of turning on or off water flow, to much more complex functions of diverting, mixing, or modulating flow.

    Refrigeration Applications: The Art of Compromise, ASHRAE Journal, February 2020
    Refrigeration is full of compromises. Even the basic vapor compression cycle is less than ideal in order to make it practical. Andy discusses these compromises and achieving maximum efficiency.

    Learning a Vocabulary for Acoustics Fundamentals, ASHRAE Journal, December 2020
    Current architectural styles have made acoustics design more important in the architecture/engineering/construction design community. This column reviews how acoustical design has become fundamental for the industry and offers a simple vocabulary of basic acoustic terms.

    Access the ASHRAE Technology Portal to search for additional articles by subject, date or name.

  • Distinguished

    Through the Distinguished Lecturer program, ASHRAE Chapters schedule lecturers equipped to speak on relevant subjects of interest. Topics include Standards and Guidelines, Commissioning, Energy Efficiency, Refrigerants, Air Quality, and more.

    Learn more, including how you can schedule a Distinguished Lecturer visit for your chapter.

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