The energy, exergy, and techno-economic analysis of a solar seasonal residual energy utilization system

Abstract

Building heating projects lead to massive energy consumption and carbon emissions. Despite solar energy being clean and abundant for building heating, it has a temporal mismatch issue in which the energy demand and provision are opposite in magnitude between the heating and non-heating seasons. This paper propounds an energy management strategy, which aims to use year-round solar energy efficiently by producing heat in the heating season and generating electricity from the non-heating season's solar residual energy. The results prove that it can meet most of the space heating demand of the target district and provide extra electricity in the non-heating season. The year-round solar effective utilization duration is elevated to 2.48-fold of the conventional solar heating project and the annual thermal energy storage efficiency of 91.22% manifests that solar energy can be utilized more efficiently than the seasonal storage system (< 60%) throughout the whole year. Furthermore, the life cycle cost analysis indicates that the unit energy cost of this system (0.102 €/kWh) is lower than the solar seasonal energy storage system. Therefore, the solar energy supply-demand mismatch problem is settled via this energy management strategy and it is prospective to be promoted worldwide in the future.