Performance Comparison of Storage Control Strategies in CSHPSS Systems

Comprehensive numerical computer simulations have been performed to investigate the effects of various storage control strategies on the thermal performance of a non-heat pump Central Solar Heating Plant with Seasonal Storage (CSHPSS) employing a constructed water volume. Different distribution temperatures, load, collector, and storage sizes were also considered in the analyses. The study indicates that the difference in the yearly solar fraction between a system with a simplified storage control strategy and an optimal, but technically more sophisticated one, would be of the order of 0.05–0.15 units (solar fraction, or, equivalently nonauxiliary fraction units). The worst control showed a performance reduction of 0.1–0.35 units compared to the optimal case, the lower value representing system configurations with adequate storage capacity.