Effect of Location and Distribution of Insulation Layers on the Dynamic Thermal Performance of Chinese Solar Greenhouse Walls

Chinese solar greenhouses (CSG) are fully passive solar greenhouses. The dynamic thermal characteristics of 15 wall configurations with one or two insulation layers were investigated numerically during clear winter days for a typical CSG design using computational fluid dynamics (CFD) models. The total wall thickness of 0.6 m and the total insulation layer thickness of 0.12 m were kept constant for all cases. For the case of a single layer of insulation, the optimum wall design consisted of (from inside to outside): 0.12 m of brick, 0.12 m of insulation, and 0.36 m of brick. For the case of two layers of insulation, the optimum wall design consisted of (from the inside to the outside): 0.12 m of brick, 0.06 m of insulation, 0.36 m of brick, and 0.06 m of insulation. This study also showed that the wall configuration having the maximum time lag and the minimum decrement factor was similar to the configurations reported by other studies, but that the maximum time lag and the minimum decrement usually used to optimize the design of insulated building walls did not result in the optimum configuration of the insulation layers in Chinese solar greenhouse walls.