The impact of climate change on air source heat pumps.

• Forecast analysis of the behavior of air source heat pumps for the next 50 years for all climate zones. • The winter heating season is expected to shorten and the summer season to lengthen. • Winter operating hours will increase in very cold climates and decrease in temperate climates. • Rising temperatures will force air source heat pumps to work in extreme conditions for longer periods in hot climates. • Under extreme winter conditions, exceeding the TOL (operating limit temperature) occurs for an increasing number of hours. Climate change will impact the building sector, but the related consequences are not fully known, especially at energy system level. This paper investigates the effect of a changing climate on heat pumps, worldwide recognized as one of the most promising technology to decarbonize the building sector. Being highly dependent on outdoor temperature, the research aims to understand how air-source heat pumps (ASHPs) will perform within climate change depending on locations and scenarios. ASHPs are considered in several locations around the world selected to cover the climate variability of the Köppen-Geiger climate classification. Future projected climate scenarios to the years 2030, 2050, and 2070 are studied under three Representative Concentration Pathways (RCPs: 2.6, 4.5, 8.5) that reflect an increasing climate change severity. The forecast analysis is conducted in terms of ASHPs seasonal coefficients of performance, working hours, seasonal and annual energy consumption. Results show how a rising average temperature facilitates, in winter, the energy transition to the use of electric heat pumps to replace fossil fuels. However, differences are found among locations, scenarios, and RCPs. The research illustrates how the two effects of heating decrease and cooling increase offset or whether one seasonal consumption prevails and where this occurs. The general trend foresees a noteworthy reduction of winter energy consumption in all climate zones. Higher decreases are found for RCP 8.5 compared to RCP 2.6 and RCP 4.5 scenarios, for both radiant floor panels and fan coils, with most variations in Hanoi (-48,24 % in 2070) and Cairo (-39,59 % in 2070). Concurrently, a major rise is estimated in cooling consumption in almost each climate zone, with wider differences within RCP 8.5. In this scenario, the increase in summer energy consumption is more extreme, ranging from a minimum in Singapore (+4.20 %) and Mombasa (+4.66 %), to a maximum in Anchorage (+87.31 %), Reykjavik (+49.89 %) and Lethbridge (+56.53 %). This increase is only partly offset by the reduction in winter energy consumption, with an overall net increment in the forecasted building's energy consumption. [ABSTRACT FROM AUTHOR]