Energetic, economic and environmental analysis of air source transcritical CO₂ heat pump system for residential heating in China

Using air source heat pump system for residential heating is a practical way to replace coal-fired boiler in China to alleviate the haze problem, and CO₂ is a promising candidate to replace hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFCs) charged into the system. A mathematical model is developed to comprehensively evaluate the energetic, economical and environmental performances of CO₂ heat pump system compared with other three traditional heating methods. The results indicate that the primary energy ratio of CO₂ heat pump is the highest and it is a rational way to utilize renewable energy with the renewable energy contribution ratio of 0.60–0.69. The initial capital cost of CO₂ heat pump is much higher due to the dominant compressor cost. The emission of CO₂ heat pump is lower than that of coal-fired boiler at seasonal performance factor above 2.44. The initial and operation cost can be gradually reduced with the mass production and energy efficiency improvement of CO₂ heat pump. It is believe that air source CO₂ heat pump system can be employed for home heating in China, especial for the hot summer and cold winter region.