Heat pumps in existing heating and hot water systems: an evaluation of primary energy savings and reduction of CO2 produced

In a previous work we recorded a significant contribution to urban air pollution attributable to heating systems powered by fuel. Thus, we propose the replacement of existing boilers for heating and domestic hot water (DHW) production systems with high temperature air-to-water heat pumps as an intervention to improve urban air quality and energy use. We analyze replacement scenarios within the entire residential building stock of two Italian cities, Milan and Salerno, belonging to different climate zones and with their own thermophysical characteristics. For each of them, the consequences of the replacement intervention in terms of primary energy savings and lower CO2 production are evaluated. The results show a reduction of primary energy consumption by 34% in Milan and 43% in Salerno, and of CO2 production by 30% in Milan and 39% in Salerno.