Investigation of dynamic thermal characteristics of passive solar heating system

The experiment is carried out to reveal the dynamic thermal performance of passive solar test house with the Trombe wall treated as the thermal boundary condition.The influencing factors of indoor air temperature are analyzed via the stepwise regression,and the result indicates that thermo-circulation induced by stack effect is the dominant factor.The heat transfer characteristics of the massive wall are investigated by the theory of frequency domain regression.The effect of the surface temperatures on natural convection is analyzed by the Rayleigh numbers.The natural convection in the channel is regarded as the superposition of two natural convection heat transfer processes occurring over isolated vertical flat plate,and the analytical results show that the flow pattern in the channel changes from laminar to turbulent and the turbulent flow covers at least half the height of the massive wall.Finally,according to the mean Nusselt numbers obtained by the experimental data,the thermo-circulation can be broken up into three phases in daytime: initiating,stabilizing and disappearing.