Sizing of Electrical and Thermal Storage Systems in the Nearly Zero Energy Building Environment - A Comparative Assessment

In order to determine the most suitable storage system for buildings with photovoltaics (PVs), a holistic analysis of the energy consumption is often required. In that sense, this paper provides a comparative assessment of thermal and battery storage in the context of nearly zero energy buildings (NZEBs). A NZEB with a PV, heat pump and a radiant floor has been considered for this purpose. The comparison is conducted in terms of the self-consumption rate and the net present value. In addition, a control strategy that maximizes the buildings self-consumption has been developed for the NZEB with thermal storage. For the NZEB with a battery, a common rule-based strategy has been employed. The results indicate that for smaller capacities, the thermal storage is better at improving self-consumption. Moreover, under a pure self-consumption scheme, battery storage becomes economically viable if investment costs are lower than 200 EUR/kWh.