Refrigerant-based measurement method of heat pump seasonal performances

There is no reliable measurement method of air-to-air heat pump seasonal performances. In this paper, we tested a method based on intrusive measurements on the refrigerant side. The method proposed uses two Coriolis mass flow meters for the measurement of the refrigerant flow rate and of the vapor quality at the indoor heat exchanger outlet. The method is validated by testing an air-to-water heat pump in laboratory conditions and by using the water enthalpy method as a reference. Results confirm that the refrigerant density measurement with a Coriolis flow meter can help to predict the refrigerant vapor quality with satisfactory accuracy if the quality is not too high. The method is also reliable in dynamic conditions (including for defrosting periods). It will then be used as a reference to check the accuracy of different in situ measurement methods for air-to-air heat pumps.