Outdated internal equipment heat gain data can result in oversized systems and higher operating costs, according to ASHRAE. The organization says it is also one of the most difficult areas for engineers to define.

To assist the building environment industry in defining these loads and designing more cost-efficient systems, internal equipment heat gain and load density data have been updated in the newest edition of the ASHRAE Handbook.

The flagship of ASHRAE’s Handbook series, the “2013 ASHRAE Handbook–Fundamentals,” 39 chapters cover basic principles and data used in the HVACR industry, including updated information on building materials, load calculations, energy resources and analysis, refrigerants, indoor environmental quality, sustainability, controls, duct and piping system design, and more.

Major revisions were made to chapter 18, “Nonresidential Cooling and Heating Load Calculations,” including the new internal heat gain data and recommendations, an elevation correction example, and an equation summary.

“Older assumptions based on out-of-date computer, copier, and printer heat gains can result in significantly oversized HVAC systems resulting in higher first cost and operating cost,” said Steven Bruning, Handbook subcommittee chair of Technical Committee 4.1, Load Calculation Data and Procedures. “The new data in the Handbook chapter reflect ongoing ASHRAE Research results.”

The chapter also includes an entirely new master example section based on the renovated headquarters for the American Society of Heating, Refrigerating and Air-Conditioning Engineers.

Additionally, the climatic design content of 2013 Fundamentals has been expanded to include data from nearly 900 more worldwide reporting stations than the 2009 volume. Chapter 14, “Climatic Design Information,” now contains temperature and humidity design conditions, and related information for 6,443 locations in the U.S., Canada, and other countries around the world.

“The increased number of stations, particularly noticeable in North and Central America, results in a better geographical coverage and enables designers to find a station closer to the location for which a building is designed,” said Didier Thevenard, chair of Technical Committee 4.2, Climatic Information.

Each station’s data now also includes monthly precipitation, used in particular to determine climate zones in Standard 90.1. The method and supporting data to calculate solar irradiance during clear sky conditions was also updated.

For more information on the publication, call (800) 527-4723 or visit www.ashrae.org.