Research on the performance of the household-type cooling-heating-hot unit in winter

A smart air conditioning unit with functions of cooling, heating and hot water supply (referred to as CHU) is proposed for heating or cooling of residential buildings. The CHU can provide cooling and heating as regular heat pump air conditioning, and also produce hot water by recovering condensation heat in summer. To study the performance of this innovative system, a prototype machine of CHU is implemented consisting of compressor, water pump and data acquisition system. In this paper, the investigation of the proposed system is focused on the performance in winter mode. Firstly, the performance of CHU for generating hot water is tested in the air source heat pump mode. Furthermore, experiments are executed on the air source and water source heat pump modes, respectively, to test the operation performance in winter conditions. The experimental results show that the system's coefficient of heating performance (COP) decreases with the condenser inlet water temperature, which selected R22 as the refrigerant material. Besides that, both modes show significant energy saving and environmental benefits, with the COP in water source mode a little larger than in air source mode.