Research On Cooling And Energy Saving Potential Of Integrated Panel Buildings With Sky Radiant Cooling Technolog

As industrialization continues,the natural phenomenon of severe destruction of the natural environment and the social phenomenon of mass movement of the working population are becoming increasingly apparent.The emergency disaster situation and the poor environment of the construction sites have led to the tension of housing problems,and temporary buildings have attracted the attention of researchers as one of the important means to solve these two phenomenon.However,compared to conventional buildings,temporary building envelope materials are usually simple and thin,with high heat transfer coefficients and low thermal inertia,and are significantly affected by the outdoor meteorological environment,leading to"overheating"and"overcooling"of the indoor thermal and humid environment.Radiative sky cooling is considered an environmentally friendly technology that effectively regulates indoor heat gains in buildings However,due to the complexity of the production process and the high initial investment,there are still only a few cases in which the technology has been applied to actual projects.Therefore,based on Energy Plus energy consumption simulation analysis software,this paper establishes a numerical-physical model of a cubicle building to investigate the cooling and energy saving potential of a prefab house integrated with radiative sky cooling technology,with the following main conclusions:Firstly,based on a typical prefab house,a numerical-physical model of the prefab house was established to explore the relationship between the cooling capacity of radiative sky cooling technology and the randomness of R andεof the external roof surface material,and the highest temperature difference values of R andεparameters throughout the day under the best and the worst cooling conditions were used as indicators to evaluate the size of the cooling capacity of radiative sky cooling technology in each region.It was found that the cooling effect of radiative sky cooling technology increases with increasing values of R andε,and the representative cities in the southern interior with radiative sky cooling technology usually possess higher cooling potential than the northern coastal cities.Secondly,based on the phenomenon that the corresponding conditions of the external roof surface of prefab house that could achieve all-day radiative sky cooling below the ambient temperature in different regions,were distributed in the range of 0.9-1.0 of R,the critical values of R andεfor achieving all-day radiative sky cooling below the ambient temperature were investigated by methods of linear fitting.The results show that the maximum design-day differences between the exterior roof surface of the prefab house and the outdoor air dry bulb temperature were linearly related to R andεof the exterior roof surface material.The linear regression equation could be used to determine whether a given material with R andεcan achieve all-day radiative sky cooling below ambient temperature in different regions.On the other hand,the minimum values of R andεcould be predicted to achieve all-day radiative sky cooling below ambient temperature in different regions,so as to guide the development and application of all-day radiative sky cooling materials.Based on the magnitude of the influence ratioα,it was concluded that the influence of solar radiation reflectivity on the value ofΔT_maxwas significantly higher than that of thermal emissivity.And to achieve all-day radiative sky cooling below ambient temperature,the prefab house in hot summer and cold winter zones and hot summer warm and warm winter zones usually had higher solar radiation reflectivity thresholds than those in cold and severe cold zonesFinally,a detailed analysis of the impact of radiative sky cooling technology on the energy consumption of prefab house was carried out,and three types of great annual energy consumption changesΔG_y,max were proposed as evaluation indicators based on a hypothetical theoretical analysis method.It was found that the higher R andεwere favorable to reduce the summer air conditioning energy consumption of prefab house,while it was unfavorable to the winter heating energy consumption,and the impact on the annual energy consumption was significantly different with the regions.However,too high solar reflectance materials caused more substantial waste of heating energy and were considered unsuitable for application in rigions with excessive winter heating energy consumption.Based on the comparison of the magnitude of the actual great annual energy consumption variationΔG_py,max,the general order of the magnitude of the annual energy saving potential that could be achieved by adjusting the R andεparameters was hot summer and warm winter climate zones>hot summer and cold winter climate zones>severe cold climate zones>mild climate zones>cold climate zones.Based on the comparison of the magnitude of theΔG_cy,max,the larger the value of R andεwas,the more applicable to the prefab house in hot summer and warm winter climate zones,while in cold and severe climate zones,it was usually not applicable due to generate more energy consumption throughout the year.Based on a comparison of the magnitude of the adaptive great year-round energy consumption variationΔG_sy,max,it was clear that slab buildings in hot summer and warm winter climate zones usually had the highest ideal state energy savings,while the mild climate zones had the lowest.This paper presents a detailed and comprehensive study of the cooling capacity and energy saving potential of the prefab house integrated with radiative skyt cooling technology.The trends of cooling capacity and various energy consumption of prefab house with the changes of R andεparameters on the external surface of the roof were understood,and the difference between the best working condition and the worst working condition（including cooling capacity working condition and annual energy consumption working condition）was used as the evaluation indicators to analyze the nationwide application,and the applicable levels of cooling capacity and energy saving potential of radiative sky cooling technology were classified.It provided theoretical guidance and data support for the subsequent engineering practical application of daytime radiative sky cooling technology.