Presentation No 622 – Performance and safety analysis of charge reduced brine to water heat pumps using R290 – 14th IEA Heat Pump Conference, Chicago, USA
The European implementation of the Montreal Protocol, the F-gas Regulation, restricts the use of refrigerants with high GWP. Thus, low-GWP refrigerants, in particular R290 (propane), are becoming the standard in the growing heat pump market. Within this contribution the results of the research project “Low Charge 150 g” are shown. The focus is on the reduction of charge needed in heat pumps, favorably below 150 g propane. As part of this project different components were combined in brine to water refrigerant circuits and experimentally evaluated. Conclusions and correlations will be described based on ErP standards and a multitude of measured values. All evaluation focus on the behavior based on charge variation and are used to create four distinct operation modes of a heat pump. Additionally, a test bench for refrigerant distribution testing was built to analyze R290 concentration development in controlled indoor scenarios. All measurements are done with compact plate-to-plate refrigerant circuits. The heating capacity reaches up to 12.85kW using 124 g R290. The current best solution achieves a specific heating capacity 4.5.