Numerical and experimental study on the thermal performance improvement of a triple glazed window by utilizing low-grade exhaust air

Abstract

Exhaust air insulation building envelope can recover and utilize the low-grade energy inherent in the exhaust air to prevent the heat transfer through the building envelope. The study investigates a triple glazed exhaust-air window (TGEW), which can switch its operation mode between the cooling and heating season. A two-dimensional numerical model was proposed to analyze the conjugated heat transfer in the TGEW. The experiment test of the TGEW was conducted and used to validate the proposed two-dimensional numerical model. The utilization efficiency of exhaust air within the TGEW was experimentally investigated under real outdoor weather condition. Numerical simulations were carried out to investigate the thermal performance improvement of the triple-glazed window by utilizing the exhaust air. Hourly and accumulated cooling/heating loads of the TGEW were calculated and compared with that of a conventional triple-glazed window (TGW). Results indicate that compared to the conventional TGW, the TGEW can reduce 25.3% and 50.1% of the annual accumulated cooling and heating loads. This demonstrates that the TGEW is applicable to the buildings installed with the fresh air supply system and can potentially contribute to decrease the cooling and heating loads through the window by utilizing the exhaust air.