Strategic Research and Innovation Agenda for Renewable ... - EGEC

RenewableHeating & CoolingEuropean Technology PlatformIn industrial applications, research is needed across all heat pump technologies toincrease their efficiency and reliability and to harness the potential for heat recoveryat different temperatures. Given that heat pumps producing heat at higher temperatures andwith a greater difference between the hot and cool side of the heat pump are needed, researchpriorities should be focused accordingly.Figure 34: Heat pump technologies and their operating temperaturesFigure 34 plots the driving temperature (“source heat”) against the delivered temperature(“heat demand”) for various heat pump technologies. Current vapour compression systemsdeliver heat at a maximum temperature of ~80°C. New vapour compression systems shoulduse low GWP synthetic refrigerants or natural refrigerants (such as butaneor water) to reach temperatures of up to 150°C. Components and materials should bedeveloped to achieve temperature lifts of up to 70 K. The use of water as the workingmedium allows the heat pump to be integrated into industrial heating processes.Alternative concepts such as heat transformers are interesting when a heat sourceof more than 90°C is available. Current systems use thermally-driven compression to upgradewaste heat from 100°C to 140°C. Reversible solid sorption reactions, such asthe reaction of salts and ammonia are applicable for heat transformation at temperaturelevels up to 250°C. Similarly, thermoacoustic systems can accept a range of driving temperaturesand output heat also in a wide temperature range. A hybrid system can be createdby adding mechanical compression as driving input to a heat transformer, allowing for useof low temperature waste heat and still generating temperature lifts of up to 100 K.57