Experimental and numerical investigation of a transcritical CO2 air/water reversible heat pump: analysis of domestic hot water production

As a natural refrigerant, carbon dioxide is safe, economic and environmentally sustainable and can be successfully utilized in heat pump and refrigeration systems operating according to transcritical cycles. This paper describes the development of a CO2 air/water reversible heat pump, specifically investigating the domestic hot water (DHW) production operating mode. A dynamic model of the heat pump is developed with the software Simcenter Amesim. After validation against experimental data, the numerical model is utilized to predict the performance of the heat pump to a varying hot water demand, evaporator air inlet conditions and high pressure value, leading to the discussion of the optimal control strategy.