LAUSR

Abstract In this paper, an optimal control approach is modelled and applied to a hybrid solar electric water heater. The hot water consumption profile of a medium density household is considered. Real historic exogenous data obtained from a weather station in the region is used as input for the developed model. The aim is to assess the cost saving potential the system can achieve under time-based pricing structure enforced by the electricity supplier in the region, while maintaining the desired temperature level of the hot water user. As a baseline, the operation of a timer-based thermostatically controlled scheme, the most commonly used method of control to minimize the energy usage and in turn the costs, is simulated. Comparisons between the operation of the HSWH with timer-based control and the optimally controlled HSWH presented a cost saving of 84.39% in the winter and 15.50% during summer period. Annual cost savings of 32.86% were noted. Additionally, the energy usage periods of the system are shifted to low demand regions of residential load profiles, decreasing the strain on the national electricity grid.