ATLANTA - Guidance to help designers improve the performance and efficiency of design as it relates to load calculations is contained in a new book from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). TheLoad Calculation Applications Manualfocuses on two methods for calculating cooling loads in nonresidential buildings: the heat balance method and the radiant time series method (RTSM).

Author Jeffrey Spitler noted that understanding these methods is crucial when answering three primary design questions: What is the required equipment size? How do the heating/cooling requirements vary spatially within the building? And, what are the relative sizes of the various contributors to the heating/cooling load?

“Cooling load calculations are performed primarily to answer the first and second questions, providing a basis for specifying the required airflow to individual spaces within the building,” said Spitler. “Answers to the third question help designers make choices to improve the performance or efficiency of the design.”

According to Spitler, the new manual features in-depth examples, as well as bringing together the latest data for building materials, windows, weather, and internal heat gains. The accompanying CD contains spreadsheets that compute the factors needed by the RSTM and compute cooling loads with the RSTM.

The manual is the fourth in a series of load calculation manuals published by ASHRAE, including the first and second editions ofCooling and Heating Load Calculation Manualas well asCooling and Heating Load Calculation Principles.

The cost of theLoad Calculation Applications Manualis $119 ($97, ASHRAE members).

To order, contact ASHRAE Customer Service at 800-527-4723 (United States and Canada) or 404-636-8400 (worldwide), fax 404-321-5478, or visit

Publication date:02/23/2009