Theoretical, experimental and numerical study on the influence of connectors on the thermal performance of precast concrete sandwich walls

Abstract

The thermal performance of precast concrete sandwich walls is in direct relation to energy efficiency of prefabricated buildings. This paper presents the theoretical, experimental and numerical studies on the thermal performance of precast concrete sandwich walls. The equivalent heat transfer coefficient model was proposed by theoretical analysis, and verified by experimental and numerical study. Six specimens with three types of connectors were fabricated, tested and modeled. The theoretical, experimental and numerical results agreed well, the accuracy of the equivalent heat transfer coefficient model was verified. It revealed how the material and geometrical parameters of connectors influenced the thermal performance of walls. The results showed that as the thickness of insulation increased from 30 mm to 90 mm, the heat transfer coefficient decreased by about 56.8%, 58.8% and 59.9% for theoretical, experimental and numerical results respectively. Meanwhile, an increased spacing and decreased connector length led to a better thermal performance, which further indicated the necessity to research the impact on thermal performance caused by connectors. It was also found that the proposed model was more suitable for the walls with stainless steel connector in this paper, for the walls with low thermal conductivity of connector like GFRP connector, the equivalent heat transfer coefficient could be obtained based on a prediction model of thermal bridge influence area and revised by correction factor in further research.