ASHRAE Research Provides Comparison Data for Unitary Equipment

By Consulting Specifying Engineer Staff November 7, 2006

New research from the American Society of Heating, Refrigerating and Air-Conditioning Engineers may well lead to better understanding of humidity control and energy cost when comparing unitary equipment.

ASHRAE Research Project-1254, Evaluating the Ability of Unitary Equipment to Maintain Adequate Space Humidity Levels, Phase II was funded in part by the Air-Conditioning and Refrigeration Technology Institute.

“The results will help designers better understand the humidity control and energy cost impacts of the unitary equipment options compared in this project,” said lead researcher Michael J. Witte, Ph.D., GARD Analytics. “Many of these options are in limited use, so actual performance experience is not available for a broad range of building types or climates. What performs well on a restaurant in Orlando may not be effective on a retail store in Atlanta. This comparison of 18 system types across seven building types in 10 climates provides additional equipment selection information.”

The project provides designers with:

• Comprehensive analysis of humidity-control performance of a wide range of DX system configurations, including sub-cool reheat, wraparound heat pipes, dual-path systems, enthalpy heat recovery and desiccant dehumidifiers.

• Significant advancement in whole building energy simulation capabilities for modeling DX equipment by adding new capabilities to ASHRAE’s EnergyPlus software program. This provides designers and analysts with access to study specific applications and extend the results of this analysis, according to Witte.

• Identification of key issues for further exploration to better understand some of the key drivers and possibly develop some simple new system configurations that can efficiently control humidity.

The final report is available at .