Optimization of photovoltaic self-consumption using domestic hot water systems

Abstract

Electrified domestic hot water systems, being deferrable loads, are an important demand side management tool and thus have the potential to enhance photovoltaic self-consumption. This study addresses the energy and economic performance of photovoltaic self-consumption by using a typical Portuguese dwelling. Five system configurations were simulated: a gas boiler (with/without battery) and an electric boiler (without demand management and with genetic and heuristic optimization). A sensitivity analysis on photovoltaic capacity shows the optimum photovoltaic sizing to be in the range 1.0 to 2.5 kWp. The gas boiler scenario and the heuristic scenario present the best levelized cost of energy, respectively, for the lower and higher photovoltaic capacities. The use of a battery shows the highest levelized cost of energy and the heuristic scenario shows the highest solar fraction (56.9%). Results also highlight the great potential on increasing photovoltaic size when coupled with electrified domestic hot water systems, to accommodate higher solar fractions and achieve lower costs, through energy management.