Thermal performance study of straw concrete external walls for rural residences in hot-summer and cold-winter zone of China

The paper aimed to investigate the eco-lightweight concrete external walls suitable for the hot -summer and coldwinter (HSCW) zone, utilizing locally available renewable materials. The study was devoted to two types of concrete: one without wheat straw (C-W-WS) and another containing wheat straw (C-WS). The effect of wheat straw addition on physical and mechanical properties, thermal and hygroscopic properties, as well as the non-airconditioned thermal environment and energy consumption of buildings, had been discussed. The results indicate that the maximum reduction in the thermal conductivity of C-WS is 13.70 % by altering the straw content and particle size. Moreover, the results of using DesignBuilder software and its application on external walls made of these materials show that, in the case of C-WS, the daily mean indoor temperature is improved compared to the case of C-W-WS. In addition, based on Adaptive Predictive Mean Voting (APMV), buildings with C-WS external walls achieved a mean improvement of 4.37 % in meeting thermal environment standards compared to buildings with C-W-WS external walls during summer design week. Moisture absorption by external walls increased energy consumption, and the annual air conditioning energy-saving of the Chongqing rural residence with C-WS external walls was 3.12 %.