Seasonal-regulatable energy systems design and optimization for solar energy year-round utilization☆

Space heating via fossil energy accounts for tremendous energy consumption and carbon emissions. Solar energy has enormous potential for building space heating in the heating season, but the more abundant solar resource is often in excess during the non-heating season, which leads to vast seasonal residual solar energy being wasted. In this paper, two solar seasonal-regulatable energy systems are proposed to solve this problem, i.e., System A: solar thermal and photovoltaic integration, and System B: solar thermal incorporating the organic Rankine cycle. Both systems are aimed at regulating the year-round solar energy for space heating in the heating season and making full use of solar seasonal residual energy for electricity generation in the non-heating season. The results show that the two systems can improve the effective solar utilization efficiency by 69.12% and 18.65%, respectively, and both can enhance the solar effective utilization period by 2.63-fold over the conventional solar thermal system. Besides, in comparison to the actual solar seasonal storage system monitoring data, both systems will dramatically decrease the investment cost by 72.69% and 72.22%, respectively. Overall, the superiority of solar seasonal-regulatable energy management systems in district-level applications is proven and it is instrumental in achieving the decarbonization goal.