High temperature heat pump integration into district heating network.

• High temperature heat pump integration into district heating network is proposed. • District heating network is studied as a heat sink and source. • Alternative refrigerant assessment is performed to replace HFC-134a and HFC-245fa. • The proposed system shows promising energy and economic performance. • The proposed integration system significantly reduces the equivalent CO 2 emission. This study illustrates the potential of high temperature heat pumps (HTHPs) integration into district heating network (DHN) through a twofold approach, using DHN as a heat sink and source. It is used as a heat sink of HTHP that uses waste heat from the supermarket's refrigeration system as a heat source whereas it is used as a heat source to HTHP that provides heat to industrial applications. When the DHN acts as the heat sink, the integrated system provides a coefficient of performance (COP) of the waste heat recovery (WHR) system between 3.2 and 5.4, reducing the operating costs between 50% and 100% with an average price ratio of 2.25 compared with the standard CO 2 refrigeration system. If the DHN is the heat source, the integrated system provides a COP from 2.8 to 5.7 for a heat sink of 110 °C. The alternative low-GWP refrigerants assessment illustrates that HC-290, HFO-1234ze(E) and HFO-1234yf were considered the ideal candidates to replace the HFC-134a, whereas HCFO-1233zd(E) and HCFO-1224yd(Z) were the most promising low-GWP refrigerants to replace HFC-245fa. Finally, the environmental results showed that the utilisation of the DHN as the heat sink in the integrated system solution produces about 60% lower equivalent CO 2 emissions than the DHN generation mix. Moreover, using DHN as the heat source, the equivalent CO 2 emissions can be reduced up to 98% in Sweden compared to conventional natural gas boilers. Hence, the combination of HTHPs and the DHN represents a step forward in the mitigation of climate change through the utilisation of sustainable energy conversion technologies. [ABSTRACT FROM AUTHOR]