The potential of wastewater-source heat pump in decarbonising buildings sector of China.

As China's economy and society continue to advance, there has been a notable enhancement in the quality of life for its people. However, the escalating energy consumption in buildings, particularly for heating and cooling purposes, has emerged as a pressing concern, accounting for nearly 60% of the overall energy consumption. In response to this challenge, heat pumps have emerged as a promising solution by efficiently meeting the demand for heating and cooling. Among these options, wastewater-source heat pumps (WWSHP) have garnered attention as an innovative choice, harnessing the waste heat in available wastewater resources in China to provide efficient heating and cooling services. The objective of this study was to comprehensively investigate the decarbonisation potential associated with sewage source heat pumps in China. By employing both techno-economic analysis and life cycle assessment methods, we conducted a thorough comparison between conventional heating and cooling systems and various heat pump systems. The results of our analysis demonstrate that WWSHPs not only exhibit the lowest greenhouse gas (GHG) emissions but also yield the lowest production costs. Our findings reveal that the potential capacity of WWSHPs amounted to a total of 2.4 EJ in 2020, with the capability to mitigate 99 Mt CO-eq emissions and achieve cost savings of 24 billion RMB. Importantly, WWSHPs' maximum potential cannot be fully realised by replacing heating alone. However, by replacing both heating and cooling options, WWSHPs unlock substantial decarbonisation potential and cost savings.