Experimental Study On The Co-cooling Characteristics Of Radiant Floor And Tunnel Air Based On Virtual Natural Cooling Sources

The radiant floor system has the advantages of good room temperature uniformity,low noise,low operating costs and high comfort,but from the existing research,the contradiction between the cooling capacity and condensation of the radiant floor system greatly affects the application of the system.The combination of radiant floor systems,tunnel air systems and natural cooling sources can give full play to the advantages of clean energy and reduce carbon emissions and environmental pollution.In this paper,a virtual natural cooling source–based radiant floor system is set up to analyse the dew condensation characteristics and dehumidification treatment at the radiant floor end and the cooling and energy consumption characteristics of the natural cooling source–based radiant floor system during operation.The dew condensation characteristics,cooling characteristics and energy consumption characteristics of the radiant floor co–ventilator system are explored from the perspective of chilled water stepped utilisation,in both chilled water tandem and mixed water modes,and the energy saving principles of chilled water stepped utilisation are analysed.The following conclusions are drawn:(1)The higher the water supply temperature in the radiant coil,the lower the risk of floor condensation,and there is a risk of condensation when the coil water supply temperature is below 14℃in the windless state of individual radiant floor cooling;in the windy state,if the fresh air moisture content is lower than the indoor moisture content and has dehumidification capacity,and the water supply temperature is higher than 10℃,there is no risk of floor condensation.(2)By fitting and analyzing the dew point temperature and surface temperature,the occurrence time of condensation is determined when the two are equal.When the surface temperature drops faster than the dew point temperature,it is recommended to determine the start warning time 600 seconds before the surface temperature and dew point temperature reach the same level.If the decrease in surface temperature is greater than the dew point temperature,condensation will occur in a short period of time.(3)The lower the height from the floor,the greater the temperature drop,the height of 0.1 m air temperature drop is the largest,only rely on individual floor radiation cooling is difficult to let the indoor temperature field to reach a uniform state in a short period of time,so the floor radiation cooling system generally need to cooperate with the air supply cooling.(4)The chilled water gradient utilisation mode,as the water supply temperature is above 12℃and combined with the duct air,no condensation will occur,with no condensation,large cooling capacity and low energy consumption as the goal,multi–objective optimisation analysis can be obtained in series water supply 0.5 m~3/h,air supply 45 m~3/h as the optimal working conditions,cooling capacity is 474.3 W,system energy consumption is 238 W.(5)Radiant floor cooling system and tunnel air system and the cold and heat sources are natural cold sources,tandem water supply using the same natural cold source water for the tunnel air system and radiation end of the water supply,to achieve the use of the cold amount step by step,reduce the system equipment costs and environmental pollution,with energy saving,environmental protection characteristics,worth promoting the application.