| With the development of industrial society,outdoor enclosures used to accommodate electronic components have been widely used in telecommunications,industry,military and other fields.The overheating of the casing will have an adverse impact on the performance and service life of the internal electronic components.It is an urgent and important topic to dissipate the heat of the casing and its internal electronic components.The commonly used forced cooling technology will consume a lot of energy and aggravate the energy problem.Radiative cooling technology is a research hotspot in recent years owing to its advantages of energy saving and emission reduction.Among them,porous polyvinylidene fluoride hexafluoropropylene（PVDF-HFP）coating has excellent radiative cooling performance,which is expected to be used to solve the heat dissipation problem of outdoor casing.However,porous PVDF-HFP coating has some problems,such as the influence of preparation process on performance,poor heat expansion performance and poor surface adhesion,which is difficult to be directly applied to outdoor casing.Therefore,it is necessary to optimize the performance of porous PVDF-HFP coating and explore in many aspects.On this basis,the research carried out in this paper is as follows:Firstly,a method of optimizing the preparation process of PVDF-HFP coating with neural network is proposed,the effects of different preparation processes on the radiative cooling performance of the coating are explored,and the optimization benefits brought by this method are evaluated.According to the calculation and experimental results,it can be found that the optimal PVDF-HFP coating can obtain an ambient temperature drop of 6℃and a theoretical cooling power of 84 W·m-2 in the daytime.Secondly,to solve the problem of poor in-plane heat expansion performance of PVDF-HFP coating,the phase conversion preparation method of micro nano porous coating is developed,and a uniform temperature radiative cooling coating compounded with carbon film is proposed.The thermal imaging results of the coating show that the composite coating can not only improve the temperature uniformity,but also have a significant cooling effect on the heat source.The outdoor temperature measurement experiment further proves the enhancement of the cooling capacity of the composite coating.Thirdly,to further improve the cooling capacity and surface adhesion of the coating,the preparation method of yttria doped PVDF-HFP coating was proposed,and the radiative cooling performance and outdoor heat dissipation performance of the coating were studied.The results show that the adhesion of the coating is greatly improved,the theoretical cooling power of 91 W·m-2 is obtained at noon,and the theoretical heat dissipation of about 2898 J can be brought to the fin radiator.On this basis,to solve the color problem of traditional radiative cooler,the preparation method of gray pigment doped PVDF-HFP coating is proposed,and the cooling performance and outdoor heat dissipation performance of gray coating are explored.The simulation and experimental results show that the gray coating can improve the heat dissipation performance of fins.Through theoretical calculation,the gray coating can bring about 1329 J theoretical heat dissipation to the fin radiator.Finally,to solve the supercooling problem of radiative cooler,based on the principle of yttria doped PVDF-HFP coating and thermal switch,an intelligent radiative cooling structure is proposed and designed,and the practical application effect of the structure is revealed.Simulation and experiments have confirmed that the intelligent radiative cooling structure can regulate the internal temperature of the glass room according to the external ambient temperature.Specifically,the structure can intelligently adjust the radiant cooling performance of the building model,to maintain the indoor thermal comfort. |
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