IIR document

Development of a modular refrigeration cycle to classify the performance of flammable refrigerants.

Number: 0128



Due to political regulations, environmentally friendly refrigerants must replace conventional alternatives (i.e., R134a) in heat pumps. Especially in residential applications, many theoretical studies in the literature prove that hydrocarbons meet many requirements and have suitable thermodynamic properties to increase the efficiency of refrigeration cycles. However, there is an urgent need for experimental validation to push the usage of hydrocarbons into practice.
In this work, a modular, safe and controllable air-to-water heat pump test bench is developed to validate the theoretical potentials of propane-based heat pump systems. Due to the modular design, different components and other non-toxic refrigerants of all flammability classes can be investigated. In addition to measuring the refrigerant mass flow rate, relevant temperatures, and pressure levels for thermodynamic analysis, the design allows the investigation of the coefficient of performance and influences of the refrigerant charge.
The propane-based heat pump is successfully commissioned. During fully automated operation, a coefficient of performance of 5.5 at an air temperature of 10 °C and a supply temperature of 35 °C is determined. The refrigerant charge is 2.34 kg. This charge ensures a refrigerant reservoir in the receiver. Charge variations show that leakage can be detected using the installed sensors after depleting the refrigerant reservoir. Refrigerant loss manifests itself in a decrease of subcooling, an increase in superheating, reduced heat flow rates at the condenser, and thus decreasing coefficients of performance. These findings can be used to integrate leakage detection into a sensor-based algorithm.

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Pages: 9 p.


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  • Original title: Development of a modular refrigeration cycle to classify the performance of flammable refrigerants.
  • Record ID : 30029726
  • Languages: English
  • Subject: Technology, HFCs alternatives
  • Source: 15th IIR-Gustav Lorentzen Conference on Natural Refrigerants (GL2022). Proceedings. Trondheim, Norway, June 13-15th 2022.
  • Publication date: 2022/06/13
  • DOI: http://dx.doi.org/10.18462/iir.gl2022.0128
  • Document available for consultation in the library of the IIR headquarters only.


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