ASHRAE - American Society of Heating@ Refrigerating and Air-Conditioning Engineers@ Inc.
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ASHRAE 90338-2007
Scope
PURPOSE OF THIS MANUAL This manual was prepared to assist entry-level engineers in the design of air-conditioning systems. It is also usable??in conjunction with fundamental HVACR resource materials??as a senioror graduate-level text for a university course in HVAC system design. This manual was intended to fill the void between theory and practice@ to bridge the gap between real-world design practices and the theoretical knowledge acquired in the typical college course or textbook. Courses and texts usually concentrate on theoretical calculations and analytical procedures or they focus upon the design of components. This manual focuses upon applications. The manual has two main parts: (1) a narrative description of design procedures and criteria organized into ten chapters and (2) six appendices with illustrative examples presented in greater detail. The user eader should be familiar with the general concepts of HVACR equipment and possess or have access to the four-volume ASHRAE Handbook series and appropriate ASHRAE special publications to obtain grounding in the fundamentals of HVACR system design. Information contained in the Handbooks and in special publications is referenced??but not generally repeated??herein. In addition to specific references cited throughout the manual@ a list of general references (essentially a bibliography) is presented at the end of this chapter. The most difficult task in any design problem is how to begin. The entry-level professional does not have experience from similar projects to fall back on and is frequently at a loss as to where to start a design. To assist the reader in this task@ a step-by-step sequence of design procedures is outlined for a number of systems. Simple rules are given@ where applicable@ to assist the new designer in making decisions regarding equipment types and size. Chapter 2 addresses the difference between analysis and design. The chapter covers the basic issues that are addressed during the design phases of a building project and discusses a number of factors that influence building design@ such as codes and economic considerations. Human comfort and indoor air quality@ and their implications for HVACR systems design@ are discussed in Chapter 3. Load calculations are reviewed in Chapter 4. The specifics of load calculation methodologies are not presented since they are thoroughly covered in numerous resources and are typically conducted via computer programs. HVACR system components and their influence on system design are discussed in Chapter 5. Chapters 6 through 8 cover the design of all-air@ air-and-water@ and all-water systems@ respectively. Here@ again@ a conscious effort was made not to duplicate material from the ASHRAE Handbook?? HVAC Systems and Equipment@ except in the interest of continuity. Chapter 6 is the largest and most detailed chapter. Its treatment of the air side of air-conditioning systems is equally applicable to the air side of air-and-water systems; thus@ such information is not repeated in Chapter 7. Chapter 9 covers a variety of special HVACR systems. Controls are treated in Chapter 10. The appendices contain detailed descriptions and design calculations for a number of actual HVACR-related building projects. They serve to illustrate the procedures discussed in the main body of the manual. The projects in the appendices were chosen to cover a variety of building applications and HVAC system types. They help to give the entering professional a ??feel?? for the size of HVACR equipment@ and they indicate how a designer tackles particular design problems. Since these examples come from actual projects@ they include values (such as thermal properties@ utility costs@ owner preferences) that are particular to the specific contexts from which they were drawn. The purpose of the examples is to show process@ not to suggest recommended or preferred outcomes. A few words of advice: do not hesitate to make initial design assumptions. No matter how far off the specific values of a final solution they might prove to be@ assumptions enable the designer to start on a project and to gradually iterate and improve a proposed design until a satisfactory solution has been obtained. Frequently@ more experienced colleagues may be able to assist by giving counsel and the benefit of their experience@ but do not hesitate to plunge ahead on your own. Good luck!
ASHRAE 90338-2007 history
2007ASHRAE 90338-2007 Air-Conditioning System Design Manual (Second Edition)