Potential of an air curtain system orientated to create non-uniform indoor thermal environment and save energy

Abstract

Non-uniform indoor environment has shown its potential for building energy efficiency and improving indoor air quality compared with traditional uniform environment created by mixing ventilation. An air curtain was employed to create non-uniform thermal environment in this study. The performance of an optimal ventilation strategy between an air curtain and the background ventilation in a typical air-conditioned room was investigated numerically. The air curtain's effectiveness and coefficient of performance (COP) are proposed as evaluation indices for assessing the efficacy of air curtain for this usage. The numerical model was validated by experiments. The energy saving potential of an air curtain system for maintaining a thermal environment of a compartment was studied under different internal heat-source characteristics. The discharge velocity of the air curtain was optimized. The results show that the efficacy of an air curtain system to create a non-uniform thermal environment is high, where the maximum temperature difference between two sides of an air curtain could be as high as 7.4℃. Both the flow rate of the air curtain and background ventilation can be reduced to save energy. An air curtain is more efficient when the heat is concentrated mainly in the unoccupied room partition and the unoccupied zone contains external walls.