| Thermal insulation is a very important ways for cooling roof, which consists of active and passive two kinds of ways.The green roof, water storage roof, evaporated cooling roof, ventilated roof and roof with insulation materials are passive insulation.The integrated water roof is a kind of passive insulation roof, which can realize the thermal insulation.However, it can’t make full use of solar energy to supply hot water for building. The aim of the paper is to develop a new type of low cost heat collection and thermal isolation cooling roof module which based on the integrated water roof, and experimentally investigate the heat collection, the thermal isolation and the scatter thermal performance of modules with contrast test on it.The experiments conclude three modules are tested and analyzed. The first module use DN25 PPR pipes as its heat transfer components, and 50mm sand as its filling material. The second module use DN25 steel aluminum composite pipes as its heat transfer components. The third module use DN40 PVC pipes as its heat transfer components,and 50mm sand as its filling material.And each module conclude three contrast modules,that is the exposed module,the heat collection module and the heat collection module without water.By measuring the temperature of water, velocity of flow, ambient temperature and relative humidity, radiant intensity, temperature of layer under different working conditions, the evaluation parameters of heat-collecting capacity, the heat-collecting efficiency and the thermal isolation performance are obtained.Furthermore,the relationship between heat collectiion and radiant intensity and the thermal isolation performance and the scatter thermal performance of the modules is comparative analyzed, which will provide the basic experimental advice for the engineering application.The characteristic of the modules are:(1)The unit heat collection of the modules are 169.7 kJ/(m2·h) 158.2-187.9kJ/(m2·h)and 196.4kJ/(m2·h).The transformation of heat collection with time of modules are similar, there is a quadratic polynomial between the heat collection and time; There is a quadratic polynomial of fow with time of the first and second modules, the transformation of fow with time of the third module is a linear increase relation.(2)The average heat efficiency of modules are 36.0%～43.0%,7.0%～19.0% and 7.0%-19.0%.The heat collecting efficiency of the third module is higher than the other about 24.0%-29.0%.The unit cost of the flat panel solar collector is about 545.9～11645.9￥/m2 higher than the heat collection modules,and the collector efficiency of flat panel solar collector is higher than the heat collection modules about 7.0%-53.0%.Changing the collector materials of the heat collection module and reducing the gap of the collector pipes can improve the heat efficiency of the module.(3)The heat conduction flux of the three modules are about 14.3 ～24.4 W/m2,5.5-8.9W/m2and5.4-6.6W/m2.The temperature rise of the modules are 3.6～5.3℃,1.1～1.6℃ and 0.8～1.1℃.The the heat flux and the temperature rise of the third module are lowest, which own a better heat insulation effect than other modules.(4)The heat conduction flux,the heat convection flux, the heat collecting flux, and the heat storage flux in net radiation of the first module are 3.0%～6.0%, 3.0%～6.0%,7.0%～19.0% and 72.0%～93.0%.And that of the second module are 1.0%～4.0%,1.0%～9.0%,7.0%～19.0% and 77.0%～97.0%. And that of the third module are 1%～2%,4.0%～7.0%,36.0%～43.0% and 50.0%～59.0%.The heat conduction flux of the second module and the third module are lower than the first module about 2.0%～4.0%;the heat convection flux of the third module is highter than the other modules about 1.0%～5.0%,the heat collection flux of the third module is highter than the other modules about 23.0%～29.0%, the heat storage flux of the third module is lower than the other modules about 22.0%～32.0%.The heat collection and the thermal isolation of the third module is better than the other modules.(5) The heat flux of the heat collection module is lower than the bare module and the heat collection module without water aboutl.0%～10.0%, the heat storage flux is lower about 15.0%-40.0%.The thermal isolation of the heat collecion module is better than the other modules. |
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