Analysis of carbon emission associated with composite air source heat pumps in buildings

The construction industry accounts for a significant portion of global energy consumption and carbon emissions. Air source heat pump (ASHP), as an environmentally friendly technology, have been widely employed in energy-efficient buildings to reduce carbon emissions. To ensure stability, ASHP is often used in conjunction with auxiliary heat sources to form composite cooling/heating systems. To evaluate the carbon emissions of ASHP with auxiliary heat source, a life cycle carbon emission model was developed in this study. The results show that the carbon emissions during building operation stage accounted for 70.5 % of total carbon emissions. The carbon emissions of single ASHP, ASHP-solar, ASHP-gas boiler, ASHP-coal boiler, and ASHP-electric boiler with different control strategies are compared. During the operation stage, the ASHP-gas boiler system has the lowest carbon emission. Taking into consideration renewable energy utilization, the ASHP-solar is preferred for the cooling/heating source of the building. Additionally, this study highlights that building location plays a crucial role in determining its associated carbon emissions. Several cities in China were studied, and the maximum levels carbon emissions are observed in Harbin while minimum levels are found in Chongqing.