Tangwe, Stephen, Michael Simon, Edson L. Meyer, Sampson Mwampheli, and Golden makaka. “Performance Optimization of an Air Source Heat Pump Water Heater Using Mathematical Modelling”. Journal of Energy in Southern Africa 26, no. 1 (March 23, 2015): 96–105. Accessed April 28, 2024. https://energyjournal.africa/article/view/2225.