Performance of a novel mechanical ventilation heat recovery heat pump system

The ventilation, heating and cooling of a building can be provided by advanced mechanical ventilation heat recovery systems (MVHR) which incorporate heat pumps. This paper covers the testing and performance of a novel MVHR heat pump system developed for the domestic market [S.B. Riffat, The University of Nottingham: Patent no. GB9522882.1, 1995; Patent no. GB9522882.1, 1996; Patent no. GB9507035.5, 1995]. The novel system uses revolving heat exchangers which both impel air and transfer heat. Low grade heat recovered from the exhaust air is upgraded by a heat pump and used for heating the fresh supply air. The system typically provides 2 kW of heating for air supplied at 250 m3/h. The prototype system has a heating coefficient of performance (COP) of up to 5 and an average system of COP 2.5 over a range of conditions. The system can also be used for cooling by switching the air flows over the evaporator and condenser. The prototype system requires very little maintenance and is compact and energy efficient.