Off-Grid Domestic Water Heating from Solar and Wind Power: a Feasibility Study

This paper presents the simplified modelling of a retrofitted house-hold geyser, powered by a small Photo-Voltaic (PV) array and Wind Turbine (WT) generator, to justify the feasibility thereof. An existing 200 l geyser (originally grid-connected) is modelled, and is assumed to supply one 100 l bath (or two 50 l showers) at a user-desired temperature of 40 degrees C, daily each evening. A recorded set of weather data (primarily solar insolation and wind speed) from the University's campus is used to approximately size the required PV area and WT diameter, to satisfy the above hot water requirements. Using the recorded weather data from 2011, a PV array area and WT swept area of similar to 6m(2) each, appears to be sufficient to provide the heating requirements throughout the year, bar one week in April. The modelling presented is somewhat simplified and lacks optimisation but intends, successfully, to demonstrate the feasibility of the application.