Thermal performance of building wall materials in villages and towns in hot summer and cold winter zone in China

Based on the current state of building wall materials of rural buildings in China consume large amounts of energy and have poor thermal performances, theoretical calculation and test detection of thermal performances were carried out for concrete block, cavity wall made of sintered Dalun brick, non-clay sintered porous brick wall, rectangular porous block construction, composite ceramic concrete block construction, steam-pressed sand concrete block masonry with gas, and concrete porous brick wall. And the experimental results of heat transfer coefficients were generally consistent with the theoretical calculations. Both test results and theoretical calculation results of the wall heat transfer coefficients are processed using the weighted average method. Among the above-mentioned walls, we found that the heat transfer coefficients for the rectangular porous block construction, composite ceramic concrete block construction and steam-pressed sand concrete block masonry with gas were 1.22 W/m2·K, 0.99 W/m2·K, and 0.97 W/m2·K. All of these materials met the standards such as Design Standard for Energy Efficiency of Rural Residential Buildings. These materials which met the standard were suitable for exterior walls of buildings and could meet the standard requirement of 50% energy saving. Gray theory analysis showed that the influencing factors such as coefficient of thermal conductivity of wall materials, wall thickness and mortar thickness had successively decreasing gray correlation degrees with the wall heat transfer coefficient.