Heat transfer performance of an assembled multilayer wall in a Chinese solar greenhouse considering humidity

Abstract

This paper presents a new type of assembled multilayer wall suitable for Chinese solar greenhouses, and studies the heat transfer performance of the wall with three different external insulation schemes. The results show that there is coupling in the heat and moisture transfer of the assembled multilayer wall in the solar greenhouse, but it is not obvious and is not sensitive to the change in humidity outside the room, which is beneficial to the construction of thermal environments in solar greenhouses. The relative humidity of the clay filling in the wall is kept at approximately 99%, which gives the wall a stable and efficient heat storage and release capacity that can basically realize one-way heat transfer between the wall and the indoor environment. There is a lag effect in the response of the temperature field in the wall to the change in the external temperature. Increasing the thickness of the polystyrene insulation board on the outdoor side in a certain range can reduce the lag effect and increase the heat storage of the wall by 24.95%, the heat released to the room by 41.72%, and the hourly average heat released during the heat release process by 3.08 times. The wall design concept is advanced, the heat storage and release performance is good, and the wall can be quickly assembled, reused and returned to the field on site, which is suitable for large-scale application in China and in the world.