Energy Saving Effect Of Solar Heat Reflecting Insulation Coatings For Buildings

Solar heat reflecting insulation coatings for buildings can reflect most sunlight and insulate the heat, so that this kind of coatings can reduce the air conditioning energy consumption in summer while increase it in winter. Current research on the solar heat reflecting insulation coating for buildings are mostly on the product itself, especially on the index of reflectivity and emissivity. The research on the association between the coating and the energy saving rate are less and indefinite, especially for the hot summer and cold winter zone, the lack of research is much more outstanding. Current now there is no systematic and feasible method to evaluate the energy saving rate of solar heat reflecting insulation coating for buildings, which affected the energy saving inspection and market promotion a lot. Therefore, the research on the annual energy consumption and energy saving rate of solar heat reflecting insulation coating for buildings is very significant.Though the combination of solar radiation model and the heat action of building outer surface, this paper expounded the insulation mechanism of solar heat reflecting insulation coatings for buildings, and proposed the solar radiation absorption coefficient is an effective parameter to typify the thermal performance of the coatings, which provided a theoretical support for the heating and air conditioning energy consumption simulation and energy saving rate evaluating of the solar heat reflecting insulation coatings for buildings.The simulation analysis showed that the heating and air conditioning energy consumption can be affected by the indoor temperature of heating period, the division of heating period and air conditioning period and the energy-consumption mode. Base on this conclusion, in order to evaluate the energy saving rate of solar heat reflecting insulation coating for buildings is very significant reasonably, we should the energy saving rate under different conditions. By analyzing the building energy-consumption with the solar radiation absorption coefficient from0.1to0.9, we established the regression equation of the solar radiation absorption and the heating energy consumption, the air conditioning energy consumption, the annual energy consumption, the annual energy saving rate. And by using the DeST to simulate the heating and air conditioning energy consumption under the conditions that the outer surface with the solar heat reflecting insulation coatings and the common coatings, we get the relative annual energy saving rate of the solar heat reflecting insulation coatings to the common coatings. The result showed that when designing according to the design standard for energy efficiency, the annual energy saving rate of the solar heat reflecting insulation coatings is less than0. And when decreasing the indoor temperature of heating period by2℃,4℃and6℃, the annual energy saving rate then became about0.2%,0.9%and2%, which were greater than0and increasing by the adjusting. Then by adjusting the calculation period of heating period and air conditioning period base on the date of climate investigation of Zhejiang province, the northern climatic region of Zhejiang province and the southern climatic region of Zhejiang province, the annual energy saving rate became about0.9%,2.6%and3.8%. So with the decreasing of the heating period, the energy saving effect of solar heat reflecting insulation coatings for buildings is increasing. Furthermore, by changing the energy-consumption mode into an intermittent way, we found that the annual energy saving rate became about1.7%,3.8%and6.4%. So we can conclude that the energy saving rate evaluation of the solar heat reflecting insulation coatings should consider the climatic parameter of the particular region, and set the indoor temperature of heating period, the calculation period of heating period and air conditioning period and the energy-consumption mode reasonably.What’s more, based on the hot-box device, we measured and calculated the heat insulation temperature difference and equivalent thermal resistance, and discussed the rationality of the test method and the evaluation index. Then come to the conclusion that because of the comparatively great difference between the spectra of simulating light sources and the sunlight, the heat insulation temperature difference measured by the hot-box device cannot represent the real insulation effect of the solar heat reflecting insulation coatings. And using the equivalent thermal resistance to typify the thermal performance, which cannot consist with the theory of working principle of the solar heat reflecting insulation coatings, is also not reasonable.