24 June 2014

COLD CLIMATE FIELD TEST OF AN AIR-SOURCE HEAT PUMP WITH TWO-STAGE COMPRESSION AND ECONOMIZING


Within a university/industry partnership, a new air-source heat pump technology
optimized for cold climates was designed, fabricated and tested in southern Indiana. The goal was to demonstrate that a cold climate heat pump (CCHP) uses less primary energy than traditional cold climate heating methods. For a field demonstration, two CCHPs were tested in two separate, nearly identical buildings located at a National Guard base during the 2012-
2013 heating season. Each building is split into halves; allowing one half to be heated by conventional methods (natural gas furnace) and the other half to be heated by the CCHP. The energy consumption of each CCHP and furnace was monitored and recorded along with
its operating conditions. The CCHP utilized two-stage compression with an economizing refrigerant loop. The CCHP
was designed for a heating capacity of 19 kW (~65 kBTU/h) at an outdoor temperature of -20°C (-4°F). The measured coefficient of performances (COPs) was in a range of 1 to 3 for
outdoor temperatures from -8°C (18°F) to 18°C (64°F). A primary energy savings of 19% was determined when comparing the two-stage heat pump to a natural gas-fired furnace.