The project, approved at ASHRAE’s 2002 Annual Meeting, is 1173-TRP, “Improvements and Validation of Unitary Air Conditioner and Heat Pump Simulation Models for R-22 and HFC Alternatives at Off-Design Conditions.” The principle investigator is Eckhard Groll at Purdue University.

ASHRAE says that the models would accurately predict off-design refrigerant conditions and system performance trends. The society also says that increased condenser size (relative to the evaporator) in higher efficiency designs makes good charge management even more important.

“Charge models that can predict at what conditions a system will begin to floodback refrigerant to the compressor or operate at excessive superheat, subcooling, or pressure ratios are important to avoid damaging operating conditions,” the society stated.

Publication date: 08/26/2002