Testing of an air source heat pump water heater in Malta

Abstract

This paper presents an analysis of performance testing of an air-source heat pump water heater in Malta. Where possible, data collection and analysis was carried out in accordance with the standard testing procedure recommended by the relevant European Norm EN255- 3:2000. Results showed that the average coefficient of performance of this heat pump between November 2009 and January 2010 was 2.75. The possibility of considering this heat pump as a renewable energy source was also studied by means of the Seasonal Performance Factor, and the minimum value required of 2.875 was almost reached (2.854). Further tests in March 2010, showed this value to have increased to 2.873 since the weather was warmer. The cooling-off trends were analysed as well as the heat losses during stand-by conditions. It was clear that the heat pump had superior insulation properties that exceeded that of traditional electric water heating boilers or domestic solar heating tanks. Test results were also compared to an electric water heating boiler, which is normally used for domestic hot water in Malta. The savings in energy consumption were found to be 70 %; while the life cycle cost analysis showed that a heat pump could be cheaper by up to 1.5 times at current prices. Comparisons to the actual performance of a typical solar heating system were also conducted. The savings in energy consumption for a solar heating system were still larger than for the heat pump and this puts solar heating as the best option for heating water in Malta, followed immediately by a heat pump.