The Design And Test On Water Spray Cooling System Of Daylighting Roof In Southern China

The glass lighting roof plays an important role in the opening characteristics of the building atrium and forms the “outdoor space” inside the building.However,the introduction of a large amount of solar radiation has greatly challenged the thermal environment of the summer atrium space.Evaporation and cooling as an effective glass roof cooling measure has not been widely used,and it is related to the failure of the corresponding spray cooling system to form a mature design method.Through literature research,theoretical analysis,numerical simulation,experimental test and statistical analysis of data,this paper finds the main meteorological elements and design parameters that affect the cooling and shading effect of the spray cooling system,and obtains the range of cooling and shading effects.Energy saving potential has formed design guidelines.Main tasks as follows:The heat transfer process of the glass roof and the sensitivity of meteorological parameters and design parameters were analyzed by modeling and calculating the transparent envelope structure attached to the water film.The results show that the cooling effect of the top spray cooling system is sensitive to solar radiation intensity,initial water temperature,solar radiation absorption rate and water flow rate of the glass,followed by air temperature and relative humidity,and the wind speed and glass thermal conductivity of the site.The sensitivity is the weakest;the incident angle of sunlight is positively correlated with the drenching flow and the shading effect of the watering system.A small light-receiving top test rig was set up,and various nozzles and flow rates were tested based on the shading effect.The results show that for the water cooling system,the flow rate can cover the roof area;the water cooling can make the lighting top The surface temperature is 8.7~12.5°C,and the radiation transmittance is reduced by 0.05 on average.The overall performance of the spray cooling system is slightly better than that of the watering system.The ruby impact spray system is optimal for cooling and shading,and the average radiation transmittance can be reduced by 0.153.Based on the results of the optimization test,the design guidelines for the spray top cooling system were formed from the selection and arrangement of the nozzle,the selection of the drenching flow,and the system opening conditions.The economic and suitability analysis of the system was carried out,and the solar energy was introduced.Driven circulating water cooling system.According to the design guidelines,the ruby impact spray cooling system was built on the atrium of the atrium and the measured results were measured.The results of the cooling system using the spray cooling system in the hot weather in summer are most significant,and the temperature can be lowered by more than 10 °C.The effect of the effect in different seasons is not much different,and the solar radiation transmittance can be reduced by about 0.1.At the same time,it is found that the intermittent spraying method has better economy,and the introduction of proper amount of spray into the upper space of the atrium can effectively reduce the indoor temperature.