A Techno-Economic Viability of a Residential Air Source Heat Pump Water Heater: Fort Bueafort, South Africa

SThe utilization of an air source heat pump (ASHP) to retrofit geyser can significantly reduce electricity consumption for sanitary hot water production. Furthermore, optimal operation of the system based on ambient conditions and capacity of hot water usage would enhance both achievable performance and payback time. The study focus on using a data acquisition system to evaluate the performance of an efficiently installed ASHP water heater and hence determine the payback period of the system. Preliminary results depict that during the four months of performance monitoring of the system, the average month-day input energy, coefficient of performance and volume of hot water usage was 3.0 kWh, 260 L and 2.2 respectively. An average monthly energy saved of 125 KWh was achieved while the average ambient temperature and relative humidity of 24.6 oC and 64.2% were recorded for the entire time of operation of the system. Finally, using a multiple comparison test, it was demonstrated that no mean significant difference occurred in both the average week electrical energy and COP for each of the different months throughout the observations. The payback period of the ASHP unit was determined to be less than 6 years from a conservative approach method.