Abstract
In the context of decarbonization efforts, heat pump water heaters (HPWHs) offer an attractive solution over conventional electric resistance type hot water systems due to their 2-3 times higher efficiency. However, the high manufacturing costs and taxes associated with using hydrofluorocarbon (HFC) refrigerant make HPWHs expensive. As a means to tackle this issue, this paper explores the use of propane (R290) as a refrigerant in HPWHs. The study involves an experimental comparison of R290 and R134a, with refrigerant charges optimized for the unit at different ambient temperatures. This current work demonstrates that R290 achieves a 10% improvement in coefficient of performance (COP) at ambient temperatures beyond 20°C. However, at 10°C ambient temperature, the study shows that R290 offers no advantage over R134a, and the COP is lower. These results indicate that the compressor is the largest source of inefficiency, and this aligns well with experimental results on system performance. Additionally, simulation tests using compressors designed for R290 did not predict better COP values than the test unit. Overall, the study suggests that R290 is a viable refrigerant option for HPWHs, but further research is necessary to optimize it’s use.
Reference26 articles.
1. Hudon K, Sparn B, Christensen D, Maguire J. Heat pump water heater technology assessment based on laboratory research and energy simulation models. Proceeding of ASHRAE Winter Conference; 2012 January 21-25; Chicago, IL, USA.
2. Enrico DR, Davide DC. Performance of a semi-hermetic reciprocating compressor with propane and mineral oil. Int J Refrig. 2011; 34: 752-763.
3. Australian Government. HFC phase-down - Frequently asked questions [Internet]. Canberra, Australia: Australian Government-Department of Climate Change, Energy, the Environment and Water; 2021. Available from: http://www.environment.gov.au/protection/ozone/hfc-phase-down/hfc-phase-down-faqs.
4. Calm JM. The next generation of refrigerants - historical review, considerations, and outlook. Int J Refrig. 2008; 31: 1123-1133.
5. Björk E, Palm B. Performance of a domestic refrigerator under influence of varied expansion device capacity, refrigerant charge and ambient temperature. Int J Refrig. 2006; 29: 789-798.