Co-optimization of passive building and active solar heating system based on the objective of minimum carbon emissions

At present, both active and passive solar heating system designs rely on the sequential design method. However, this method fails to account for the correlation between passive components and active systems, leading to poor synergy between passive solar technology and active heating systems. Therefore, a collaborative simulation model of active and passive solar heating systems was constructed in this study. In addition, an optimization model with the objective of minimization carbon emissions of buildings and the active system was developed, and the sunspace depth, building envelope parameters, and the equipment capacity were optimized and simulated. The results indicate that the optimized total carbon emissions of solar active and passive heating systems can be reduced by up to 26.5%–50.3% compared to passive building and boiler combined systems. The optimized solar fraction of solar active and passive heating systems exceeds 85%. Furthermore, higher energy efficiency of heat source equipment in the active system has been related to a lower thermal insulation performance of the enclosure structure and a greater building load undertaken by the active system. In the active solar heating system, the higher the efficiency of the auxiliary heat source, the more the heating load is borne.