Abstract:
In this paper, the optimal energy management of a hybrid solar electric water heater is presented. A typical
medium density household is considered. Actual historic exogenous data, obtained from a weather station in the
considered area is used as input for the established model.
The aim is to evaluate the energy and cost saving potential of the system, that may be achieved under timebased
pricing, while maintaining a comfortable thermal level of the hot water user.
Comparisons between the operation of a thermostatically controlled traditional electric storage tank water
heater and the hybrid solar electric water heater, offered an energy saving of 75.8% in the winter and 51.5%
during the summer period.
A life cycle cost (LCC) analysis is presented, where the project lifetime is taken over 20 years. The LCC
analysis of the hybrid system demonstrates a 44% saving in overall cost, as compared to a traditional water
heating system. Simulation results conclude that the break-even point for the evaluated system was at R10 870 in
3.3 years, under the evaluated time-based pricing structure.
