Empirical model to determine electricity demand reduction in the South Africa residential sector by retrofitting geysers with air source heat pump

Abstract

ASHP water heater is a renewable energy device for sanitary hot water production and can effectively operates with a COP above 2. In the South Africa residential sector, Eskom embarks on reducing the electricity demand from the geysers by retrofitting these systems with ASHP units. The research focused on designing and construction of DAS to monitor the power consumption of a 4 kW geyser and a 1.2 kW ASHP unit retrofitting the geyser with respect to the variability in climatic condition, volume of water drawn off, ASHP inlet and outlet water temperature. The results obtained from the experimental setup were used to develop a MLR model to predict the COP of the ASHP water heater. Finally, the result was populated to account for the total number of these above mentioned system proposed to be installed and hence the demand reduction computed. The average maximum weekday Eskom peak hours power consumption for the geyser was 3.70 kW, while for the ASHP water heater was 1.51 kW with an average COP of 2.10. The demand reduction will provide a dual benefits as its will reduced the constraint on the national grids and also the environmental pollutants.