Thermal performance of cavity masonry wall structures in the solar rich areas of Western China

Abstract

Air cavities can effectively improve the thermal performance of building envelope. A cavity masonry wall (CMW) is a common and suitable envelope in the solar rich areas of Western China for integrating thermal insulation and heat storage. However, suitable structures for CMWs have not been obtained for different indoor and outdoor climates, which hinders the realization of near-zero energy buildings. In the present study, thermal performance was analyzed for different CMW structures to obtain the design method of the CMW structure. A mathematical model of CMWs was established and validated based on experiments. This model was used to analyze the effects of different structures for CMWs, and suitable structures were determined. Climate adaptability characteristics were analyzed for the suitable structures. Finally, the energy performance of buildings with CMWs was analyzed. A climate index for CMW structure design comprising the ratio of cooling relative to heating (RCH) was proposed to divide the outdoor climate, with winter heating when RCH ≤0.17, and winter heating and summer cooling when RCH >0.17. The suitable structures were obtained in different indoor and outdoor climates, where the closed air cavity was preferably placed on the low temperature side of the construction. The suitable structures exhibited better heat transfer attenuation delay characteristics to adapt to indoor and outdoor climates. It had a significant impact on the heating load compared with buildings with masonry walls, and a saving of above 10%. The design method of CMW structure proposed in this study can provide guidance for the application.