15 May 2023

Presentation No 431 – High temperature test results and application cases of a Rotation Heat Pump – 14th IEA Heat Pump Conference, Chicago, USA

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The environmentally friendly working fluid, based on noble gases like Helium, Argon and Krypton, is used in
the counterclockwise Joule-cycle in a Rotation Heat Pump (RHP). Combined with centrifugal compression
this leads to a very high Coefficient of Performance (COP) at high sink outlet temperatures compared to
conventional compression heat pumps. Since the realized Joule-Cycle is based on an always gaseous working
fluid, the heat transfer in the heat exchangers is sensible. Therefore, neither the issue of lubrication of the
compressor nor the critical point of the working fluid limit the maximum sink output temperature. The data
shown provides information about the electricity consumption, the flow temperatures and the heat output
provided by the system. The results show that the prototype of the RHP K7 can achieve a COP >3.5 for sink
outlet temperatures higher than 100 °C. The correlations between the main rotor speed, temperature spread
and thermal power are analyzed for the test run as well. Based on this, application cases in the industry and the
field of energy services are presented and the advantages of the Rotation Heat Pump are described. Those are,
for example, the high spread of sink and source when providing cooling and heating as well as the flexibility
using one machine at different temperature levels. Further, an outlook for adaptions to realize sink outlet
temperatures >150°C will be given.