Study finds natural refrigerants more energy efficient than HFC and HCFCs in geothermal heat pumps
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A study on refrigerants used in geothermal heat pumps in a 14-storey residential building in Iran, has shown that ammonia and hydrocarbon produce significantly better Coefficients of Performance (CoP) when compared to HFC-134a and HCFC-22.
The researchers monitored performance of a horizontal closed-loop ground heat pump with a cooling load of 915 kW (260 TR) in the town of Qazvin. Ammonia came out as the most energy efficiency refrigerant with a CoP of 4.663. Hydrocarbon, n-butane’s COP was 4.606. Overall the natural refrigerants had COP’s 4.5%-5.8% higher than HFC134a. Similar results were obtained for open-loop and vertical closed-loop ground heat exchangers.
The study also found ammonia and n-butane to have a reduced initial system cost compared to HCFC-22 and HFC-134a in terms of initial system cost.
