Experimental analysis of a R600 high-temperature heat pump in sub-critical and trans-critical operation

Manuel Verdnik*, René Rieberer

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


High-temperature heat pumps can provide process heat by lifting recovered waste heat to temperature levels needed for industrial processes. The application of a trans-critical cycle extends the operating range of a heat pump beyond the critical temperature of the used refrigerant. A prototype of a high-temperature heat pump using R600 was developed and investigated. The one-stage cycle uses a suction gas cooled reciprocating compressor, a low-pressure accumulator and an internal heat exchanger (IHX) for suction gas superheating. Experimental data of sub-critical and trans-critical operation is presented. In sub-critical operation, a coefficient of performance (COP) of 4.5 at a heat source inlet temperature of 60 °C and a heat sink outlet temperature of 110 °C and in trans-critical operation a COP of 3.1 at a heat sink outlet temperature of 160 °C was achieved. The measurement data further shows a dependency of the COP on the high-side pressure and suction gas superheating realized in the IHX.

Original languageEnglish
Title of host publication14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings
Number of pages6
ISBN (Electronic)9782362150401
Publication statusPublished - Dec 2020
Event14th IIR-Gustav Lorentzen Conference on Natural Refrigerants: GL 2020 - Online, Virtuell, Kyoto, Japan
Duration: 7 Dec 20209 Dec 2020

Publication series

NameRefrigeration Science and Technology
ISSN (Print)0151-1637


Conference14th IIR-Gustav Lorentzen Conference on Natural Refrigerants
Abbreviated titleGL2020
CityVirtuell, Kyoto
Internet address


  • COP
  • Hydrocarbons
  • Industrial Heat Pump
  • Trans-critical Cycle

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Electrical and Electronic Engineering
  • Control and Systems Engineering

Fields of Expertise

  • Sustainable Systems


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