Thermal performance and passive energy saving optimization of prefabricated houses in Xinjiang region

Xinjiang uygur autonomous region in China experiences low winter temperatures and strong solar radiation. Actual test results showed that the indoor temperature of a conventional prefabricated house dropped to −10.02 °C at night, resulting in high heating energy consumption of 80.08 kWh. After insulation transformation, the minimum temperature improved by 4.94 °C and heating energy consumption was reduced by 46.7 %. TRNSYS was utilized to develop the prefabricated house model and the genetic algorithm coupled with MATLAB is employed to perform the optimization calculations by considering the thicknesses of thermal insulation materials on external walls and roofs as variables for optimization. The results indicate that the GA-optimized scheme suggests 300 mm of roof insulation material, 360 mm of floor insulation material, and 110 mm for the north wall as well as 100 mm each for the south, east, and west external walls. Compared to original scheme1, it effectively achieves a reduction in the annual cost value to 6037.09CNY, representing a decrease of 489.853CNY, along with an energy consumption of 9428.36 kWh, reflectiong a reduction by 13.48 %.This study provides experimental data and passive energy-saving optimization solutions for improving thermal performance in retrofitting prefabricated houses.