Simulative Investigations Of Thermal Performance Of Solar Building With Collector-storage Wall In Winter

The increase of energy consumption in buildings aggravates energy pressure and also increases the greenhouse gas emission which destroy natural environment. Through calculation, CO₂ emission of residential buildings in China accounts for 34.3% of the total emission in 1999, which is 1032.57 million tons (including the use of home electric appliances, heating in urban area in winter and living energy consumption in the countryside). The available application of collector-storage wall which fully uses the solar energy sufficiently has great meaning.The numerical model is built and validated for static heat transfer in the collector-storage wall system and is also used to investigate the effect of various factors on the thermal performance of the system. It is found that use of absorber could increase significantly the thermal performance of the system, but the increase of proportion of absorptance to emittance does not mean the notable augment of indoor heat gain. The higher air gap height is, the more indoor heat gain is. There is an optimal combination of the dimension of the vent height and the air gap width. Through the simulation of three kinds of collector-storage wall structure patterns, it is found that coupled heat transfer pattern gains more heat in the day. The air temperature in the air gap and the outside surface temperature of massive wall in the vertical direction are simulated and the curve equations are got through fitting which are separately exponential growth and parabola equation. It is found that the equal heat flux of outside surface of massive wall when calculation is simplified is better than equal temperature as the boundary condition. It has less difference of the heat transfer coefficient across the outside surface of massive wall. Because of reverse flow in the upper vent, the temperature and velocity distribution across the outlet section is not uniformly. So the special positions should be measured to get a representative experimental result.When the collector-storage wall system is considered in the whole building system, the energy simulation method is used to calculate various forms of heat transfer and hourly heating loads in the solar house and reference house in a heating period with a representative year weather data. The simulative results show that the total heating loads in solar house are 24.4% less than those in the reference house in the whole heating period in Shenyang when indoor air temperature is kept to be 18℃ in the houses with ideal auxiliary heat. It is also found that the increase of massive wall thickness reduces the variation of heating load. But ithas less effect on the whole heating load and daily mean indoor air temperature without auxiliary heat. The absorber on the outside surface of thermal storage wall and the improvement of glass performance could increase significantly the indoor air temperature and indoor heat gain. The simulated dynamic heating load will guide the choice of auxiliary heat scheme and the equipments in the passive solar buildings.