Prediction and Analysis of the Thermal Performance of Composite Vacuum Glazing

Yangjie Shi,Ruihong Zhang,Haiyang Xu,Jianfeng Zhang,Xiaobo Xi,Yifu Zhang

doi:10.3390/en14185769

Abstract

In this paper, a prediction method of the heat transfer coefficient of composite vacuum glazing (CVG) is proposed. By analyzing the heat transfer process of CVG, the theoretical calculation formula for the heat transfer coefficient of CVG is established. CVG temperature variation under the test conditions specified in the national standard is simulated using ANSYS. The CVG heat transfer coefficient is calculated by combining the theoretical formula and simulation results. The simulation results are then verified by comparison to a physical experiment. The results show that the deviations between the experimental and predicted values are ≤3.8%, verifying the accuracy of the simulation results and proving that the model can be used in engineering practice. Furthermore, the effects of different coating positions on the heat transfer performance of CVG are studied. The results show that different coating positions have a significant impact on the heat transfer coefficient of CVG. The heat transfer coefficient is shown to be lowest to highest under the following conditions: when the Low-E coatings are located on both sides of the vacuum layer (2LC-V), followed by Low-E coatings on the side of glass pane II near the vacuum layer (1LC-V), Low-E coatings located on the side of glass pane I near insulating layer (1LC-I), and finally, when there are no Low-E coatings (NLC) on the glass panes. Overall, this model is an effective and accurate analysis method of the heat transfer coefficient.

Highlights

The energy lost by windows accounts for 45–50% of a building’s energy consumption
composite vacuum glazing (CVG) is made by adding a glass pane on the basis of the vacuum glazing which has been sealed and formed, in which the middle part is separated by sealant and filled with an inert gas
The heat transfer coefficient of the CVG was predicted by combining a simulation analysis and theoretical calculations

Summary

Introduction

The energy lost by windows accounts for 45–50% of a building’s energy consumption It is a critical medium of heat exchange in a building. The insulating performance of insulating glazing is better than that of ordinary flat glazing because the thermal conductivity of the internal gas layer is much lower than that of glass. This technique is widely used in various buildings because of its simple manufacturing process and good safety performance [7,8]. The vacuum is formed by heating and vacuum-pumping in a vacuum furnace This technique has distinct thermal insulation properties compared to other types of glass because of the existence of the vacuum layer. It cannot be directly used as a glass curtain wall for high-rise buildings and other settings requiring safety glass [9,10,11]

Methods

Results

Conclusion