Investigation of vertical thermal stratification and stratified air conditioning load for large space with low-sidewall supply air based on vertical temperature node model

Abstract

Large space buildings often use stratified air conditioning, which has the advantages of reducing energy consumption and improving indoor air quality. The airflow pattern of low-sidewall supply air is a common technology for creating stratified air conditioning in large space. The vertical temperature dynamic distribution is a momentous feature in stratified air conditioning thermal environment, and it is also the key to attain energy saving. In order to explore the heat transfer evolution process for large space stratified air conditioning, a vertical temperature node model for predicting the thermal stratification was established based on the airflow pattern of low-sidewall supply air. In this node model, the large space indoor environment is divided into several air layers in the vertical direction. Each air layer is considered about the aspects of wall convection heat transfer, supply air heat transfer, airflow heat transfer between air layers, temperature differences heat transfer between air layers and so on. A series of heating balance equations are established, and the vertical temperature dynamic distribution results can be obtained by matrix iterative calculation. Based on the 24-h periodic heat flow, the calculated results of the node model were compared with the experimental results. Then, based on the vertical temperature node model, the heat transfer evolution process and dynamic cooling load calculation of large space stratified air conditioning with low-sidewall supply air were discussed and investigated quantitatively.