Economics, testing and evaluation of an exhaust air heat pump for R.2000 (tight) houses.

Three balanced airflow ventilation devices were evaluated, an exhaust and supply fan (E&SF), air-to-air heat exchanger (ATAHE), and exhaust air heat pump (EAHP), which can be used to increase the ventilation rate in an R-2000 (tightly constructed) type house. A prototype of the EAHP, which uses a combination of heat pipe and heat pump, was built and tested. A frosting and non-frosting version of the EAHP were evaluated. The non frosting version provided the best overall performance. The capacity of the non frosting unit, using an additional 1 kw electric resistance heater at low outdoor temperatures, ranged from 75000 Btu/h (2.2 kW) at 59oF (15oC) outdoor temperatures to 13400 Btu/h (3.93 kW) at -13oF (-25oC). The coefficient of performance (COP) of the non frosting unit (including the electric resistance heater at low outdoor temperatures) had a maximum of 4.8 at 14oF (-10oC) and a minimum of 2.4 at -13oF (-25oC).