The performance of split and integrated types of air-source heat pump water heaters in South Africa
Keywords:coefficient of performance; vapour compression refrigeration cycle; renewable energy technologies
Renewable energy technologies that can provide optimum and cost-effective energy savings to mitigate global warming, energy crisis and to achieve energy efficiency continue to be of paramount importance. The present study focused on identifying critical parameters such as the volume of hot water drawn off; ambient temperature; relative humidity; refrigerant temperatures at the inlet and outlet of the compressor and condenser; and deterministic quantities such as time used, power consumption and coefficient of performance (COP) as indicators to benchmark the performance of both the split and integrated types of air-source heat pump (ASHP) water heaters. The basis for analysis was on two predominant scenarios: first-hour heating rating and the heating cycle due to controlled volume of hot water drawn-off wherein both the integrated and split types ASHP water heaters experienced vapour compression refrigeration cycles. A data acquisition system was constructed and implemented to monitor the performance of both systems. The results obtained during summer season showed that, under the scenario of 150 L hot water withdrawal, the average COP of the systems was 3.18 and 2.85 for the split and integrated types respectively. The average power consumed was 1.29 (split type) and 0.85 kW (integrated type). The times of operation were 84 minutes (split type) and 138 minutes (integrated type).
Aprea, C., Greco, A. and Rosato, A. 2008. Comparison of R407C A heat transfer coefficient and pressure drops during flowing boiling in a horizontal smooth tube. Energy Conversion and Management 49(6): 1629-1636.
Bodzin, S. 1997. Air-to-water heat pumps for the home. Home Energy, 14(4).
Bryson, D. 2011. Eskom key reason South Africa is a big polluter. Association Press, 24, 679-684.
De Swardt, C.A. and Meyer, J.P. 2001. A performance comparison between an air-source and a ground-source reversible heat pump. International Journal of Energy Research 25(10): 899-910.
Huang, B.J. and Lin, F.H., 1997. A compact and fast temperature-response heat pump water heater. In ASME 1997 Turbo Asia Conference, V001T13A002-V001T13A002. American Society of Mechanical Engineers.
Levins, W.P. 1982. Estimated seasonal performance of a heat pump water heater including effects of climate and in-house location (No. ORNL/CON-81). Oak Ridge National Lab., TN (USA).
Meyer, J.P. and Tshimankinda, M. 1998. Domestic hot water consumption in South African townhouses. Energy Conversion and Management 39(7): 679-684.
Morrison, G.L., Anderson, T. and Behnia, M. 2004. Seasonal performance rating of heat pump water heaters. Solar Energy 76(1): 147-152.
Tangwe, S., Simon, M. and Meyer, E. 2016. Design of a heat pump water heater performance monitoring system: To determine performance of a split type system. Engineering Journal of Technology and Design14(4):739-751.
Tangwe, S., Simon, M. and Meyer, E. 2014. Mathematical modelling and simulation application to visualize the performance of retrofit heat pump water heater under first-hour heating rating. Renewable Energy 72: 203-211.
Tangwe, S., Simon, M. and Meyer, E., 2014. Analytical evaluation of the energy losses of an air source heat pump water heater: A retrofit type. Journal of Energy and Power Engineering 8(7): 1251-1257.
Tangwe, S., Simon, M., Meyer, E.L., Mwampheli, S. and Makaka, G., 2015. Performance optimization of an air source heat pump water heater using mathematical modelling. Journal of Energy in Southern Africa 26(1): 96-105
Van Eeden, S.J., Jacobsz, S.W., Rust, M. and Rust, E., 2016. Electricity generation as a beneficial post-closure land use option for a dormant tailings storage facility. Journal of the South African Institution of Civil Engineering 58(1): 53-61.
Ye, X., Xia, X. and Zhang J. 2012. Residential heat pump rebate programme. Energy efficiency measurement and verification practices, Ed. Xia, X. and Zhang, J. Media in Africa (Pty) Ltd, Unit G, Castle Walk Corporate Park.
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