A descriptive study on the convolution analysis of the insulation performance of non-transparent enclosures corresponding with the changes of the construction hierarchy

Abstract

Steady-state calculation and analysis are often inconsistent with actual conditions, because buildings are usually in unsteady heat transfer conditions; however, studies on heat transfer in the unsteady state usually adopt experiments and simulations, which do not allow consecutive analysis corresponding with the changes of the independent variable of construction. Therefore, the solution to the equation of heat transfer in the unsteady state is of great importance to the consecutive analysis of heat transfer condition in the unsteady state. Adopting the methods of both convolution calculation analysis of heat transfer in the unsteady state and experiments, the researchers ranked the four types of construction insulation performances of non-transparent enclosures of subtropical buildings in summer, including external thermal insulation, self-insulation, and two type of internal thermal insulation due to the change in the thickness of the insulation layer. As a result, the maximum value of indoor temperature in the actual condition is different from the one from the calculation of the steady steady-state but consistent with the one from convolution analysis of the unsteady state. Both the actual situation and the results of unsteady convolution calculation prove that we should not hastily draw the conclusion as to the “winner” between “inner heat preservation” and “outer heat preservation”. The unsteady convolution calculation enables us to better conduct a continuous and quantitative description and prediction of the insulation performance of the constructions in the working condition and their ranking along with the changes of construction layer.