Measured Performance of a Low Temperature Air Source Heat Pump

A study conducted by NREL measured the performance of a 4-ton low temperature heat pump (LTHP) system over a 20 month period. The study measured parameters including system and subsystem power, various temperatures, air flow, and system status in 1-minute intervals which enabled calculation of heat production and coefficient of performance (COP) by the minute, day, and for the full heating season. The results of the study show that the technology lived up to claims by the manufacturer that the system could operate down to -30°F and supply all of the heat needed for home with very minimal use of a supplemental heat source. The data showed that the system achieved a seasonal coefficient of performance (SCOP) of approximately 2.80 over the 20 month period.