被动式太阳能加热系统动态热特性研究

Investigation of dynamic thermal characteristics of passive solar heating system

为揭示特隆布墙体作为热边界条件的被动式太阳能实验房的动态热特性,对被动式太阳能实验房进行了实测;根据相关性理论分析了室内空气温度的多种相互耦合的影响因素,表明烟囱效应诱导的空气热循环是影响室内空气温度最显著的因素;根据频域分析理论研究了集热蓄热墙的传热特性;利用Ra数分析了各壁面温度对自然对流换热的影响;将间层内的自然对流简化为两个垂直平行平板的大空间自然对流问题,分析确定热循环过程中间层内的空气处于从层流到湍流的复杂流态,湍流至少覆盖墙体高度的一半;最后,根据拟合得到的平均Nu数,将空气热循环划分为起始、稳态和消失3个阶段.

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.