The Influence Of Solar Radiation Absorption Coefficient On Thermal Performance And Energy Saving Effect Of Solar Heating Building

The western region of China is rich in solar energy resources and is an important energy base with great potential for the development of passive solar buildings,but due to the vast territory of the western region and differences in climatic conditions across the region,the types of passive technologies and design parameters suitable for different climatic conditions are not specific,which makes the promotion of passive solar buildings challenging.For non-transparent envelope structure,a portion of the solar heat is absorbed and stored in the structural thermal mass of the exterior walls,which essentially affects the indoor thermal environment.and this heat is influenced not only by the performance of the wall itself,but also by the solar radiation absorption coefficient of the external surface.How to maximize the passive solar radiation heat gain of the outer wall of the building in winter has become a key issue.Therefore,this paper first grasps the basic theory of heat transfer in indoor thermal environment and two important parameters-additional thermal resistance percentage and additional thermal inertia index through theoretical analysis.On this basis,the physical model of typical buildings is established.The influence of solar radiation absorption coefficient on indoor thermal environment and energy saving effect is analyzed by combining theoretical analysis with numerical simulation.The main results of this study are as follows:(1)The ’ additional thermal resistance percentage ’ and ’ additional thermal inertia index ’ ar e selected as the main parameters for subsequent calculation.The outdoor comprehensive tempe rature is decomposed into outdoor dry bulb temperature and solar radiation equivalent temperatu re.The additional thermal resistance percentage and additional thermal inertia index under diffe rent solar radiation absorption coefficients in Lhasa,Yinchuan and Xi ’an are calculated,The cha nge rule is summarized:the larger the solar radiation absorption coefficient is,the greater the ad ditive thermal resistance percentage is,the less the added heat inertia index is.(2)The influence of solar radiation absorption coefficient on the heat transfer and heat loss of the envelope structure and the temperature of the internal wall surface is studied using the analytical method of theoretical calculation based on the characteristics of the outdoor thermal environment in winter in the western region.The findings indicate that improving the external wall’s thermal performance will result in a reduction in the susceptibility of the wall’s thermal performance to the solar radiation absorption coefficient.(3)Based on the characteristics of the outdoor thermal environment in the Yinchuan area in winter,the effect of solar radiation absorption coefficient on heating and air conditioning energy consumption and total annual energy consumption under the circumstances of different heat transfer resistance external walls,indoor calculated temperature and heating method by numerical simulation was analyzed,and regression equation was obtained in accordance with this.Finally,the total annual build-up of energy was calculated.The findings demonstrate that raising the solar radiation absorption coefficient decreases the energy needed for heating in the winter but has the opposite effect on the energy needed for air conditioning in the summer,proving the efficacy of the energy-saving measure of modifying the solar radiation absorption coefficient of the external wall surface.It is hoped that this paper will provide an effective reference for the retrofitting of rural houses in the western region to achieve sustainable development with low energy consumption.