Theoretical Development of Supersonic Compressors for High Efficiency Industrial Heat Pumps

The electrification of industrial heating processes is seen in conjunction with combinations of waste heat recovery applications, heat networks and geothermal energy resources which are part of the UK’s heat decarbonisation pathways. The aim of this research is to model advanced vapour compression heat pump technology that incorporates high-speed compressors to improve efficiency of high temperature lift industrial heat pumps.

Given that it is beneficial to also avoid environmental impacts directly caused by the working fluids, water (R718) will be initially considered as the working fluid. High Coefficients of Performance (COP ≥ 5) at lower temperature lifts for turbo (centrifugal) compressors have been achieved but challenges remain in terms of increases in impeller size with increased temperature lift, choice of bearings (gas-lubricated, magnetic etc), efficiency, compactness and the higher speeds and temperatures proposed. Speeds of 100,000 rpm to 650,000 rpm are now feasible at lower temperatures.

Thus, the novelty is to take this technology basis and model its operation at higher temperatures and pressures (that are well within standard refrigeration plant tolerances) in order to address a hard-to-treat sector of industrial heat decarbonisation. This is then a precursor to the development of a future experimental system.