Discusses the field testing of a high-efficiency, natural gas engine-driven heating and cooling system for residential and light commercial applications. Provides a product description and discusses the basic operating principles. Presents field test results which confirm high seasonal operating efficiencies with a heating coefficient of performance (COP) between 0.9 and 1.1, depending on climate, application and user comfort preference. Also briefly addresses operating costs, comfort and reliability/life considerations.

KEYWORDS: year 1995, Heat pumps, heating, cooling, natural gas, gas engine heat pumps, testing, coefficient of performance, cost in use, thermal comfort, service life, reliability, efficiency, split heat pumps