What is it about?
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.
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Why is it important?
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.
Perspectives
More building environment variables (doors and windows, ventilation volume, building orientation, etc.) are introduced to make the research results more realistic, and analyzing thermal insulation performances of special building envelopes (such as oyster shell walls and etc.) by convolution calculation method, should be the direction of follow-up researches.
Professor Jian TANG
Jinan University
Read the Original
This page is a summary of: A descriptive study on the convolution analysis of the insulation performance of non-transparent enclosures corresponding with the changes of the construction hierarchy, Journal of Computational Methods in Sciences and Engineering, August 2023, IOS Press,
DOI: 10.3233/jcm-226766.
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