Efficient heating of buildings by passive solar energy utilizing an innovative dynamic building envelope incorporating phase change material

To utilize effectively passive solar energy for heating buildings, an innovative building envelope is proposed, and its superior performance is for the first time experimentally demonstrated by constructing and testing its full-scale model. The proposed envelope comprises a dynamic Trombe wall incorporating phase change material (PCM). Its salient feature and novelty are its innovative multi-panel solar collector-storage wall and the ability of each panel to independently rotate about its vertical axis. One face of each panel is cladded with PCM, and in a typical 24 h cycle, during sunshine hours, this face is turned towards the incident solar irradiation and the rest of the time towards the conditioned space. The thermal performance of the proposed envelope is compared with that of a companion envelope having a traditional static Trombe wall with the same amount of PCM and wall geometry. The results show that compared to the traditional envelope, the new envelope regulates the thermal load more evenly by preventing large temperature swings, it reduces heat loss during the solidification phase of PCM by 29% and is overall 20% thermally more efficient. These benefits can result in energy saving from non-renewable energy sources over the design life of the building.