Experimental Investigation of Natural Convection in Trombe Wall Systems

Abstract

In this paper, experiments with a passive solar building with Trombe wall in the north cold climate are carried out and discussed, and the natural convection heat transfer process has been investigated. The relativity of the factors affecting indoor air temperature is analyzed with the stepwise regression method. The results indicate that thermo-circulation induced by the stack effect is the dominant factor. The natural convection in the channel is fairly complex; it changes from the laminar flow to the turbulent flow and the turbulent flow covers at least half the height of massive wall during the normal circulation. The flow in the channel is considered as natural convection between vertical plates. Analyzing the natural convection heat transfer process with the Rayleigh number and the mean Nusselt number, the thermo-circulation can be divided into three periods in the daytime: coast up, maintenance and weaken. During the maintenance period, the changes of the solar radiation intensity and surface temperatures have little effect on Nu number.