18 May 2017
In general there is a huge potential on using multiple heat sources for heat pumps (HPs). But to arrive at concepts which are making sense from a thermoeconomical point of view it is of decisive importance to minimize the development costs to be able to use two heat sources. One approach could be the usage of a typical air-to-water HP and its heat source ambient air together with exhaust air as a secondary heat source. In case of increasing air-tightness of residential buildings ventilation systems are very often installed by default. Thus the development costs to use this secondary heat source can be considered as negligible. In the context of this objective a fin-and-tube heat exchanger was sized as evaporator.
In this work the sizing process for a newly developed refrigerant distributor, the circuitry of this evaporator and testing results are presented. The experimental results comprise the refrigerant and air side maldistribution in case of using ambient air, exhaust air or the combined usage of these two heat sources.