The Compound Study Of Radiant Cooling And The Mode Of Fresh Air Supply

As a new air-condition system, cooling radiant ceiling panel has advantagessuch as great comfortable level, less room occupation, lower running costs, ect, but itis limited to be widely used because the moist air easily condense at the surface ofcooling radiant ceiling panel. Inlet of fresh dry air can rapidly reduce the possibilityof air condensation. This paper mainly discuss cooling radiant ceiling panel system—the factors which could influence capillary tube’s cooling capability, air flowdistribution in the cooling radiant ceiling panel room, heat transfer of all the surfacesin the room and the best position of inlet in the cooling radiant ceiling panel room bymodeling an office in the practical project.Firstly, the paper introduces capillary tube cooling system, its advantages anddisadvantages. Model a cooling radiant ceiling panel room using CFD, and analyzethe factors of cooling capability in the cooling radiant ceiling panel room withoutsupplement of air, and those factors are both structure and regulation. The resultsshows that the thickness of plaster and the distance of pipes have great influence oncapillary tube cooling capability while the thermal conductivity of plaster and thekinds of capillary tube（size S, size U, size G）have little impact on capability tubecooling capability, and cooling capability of capillary tube with plaster is about twiceas capillary tube without plaster. The mean temperature of supply water and returnwater has great effect on cooling capability of capillary tube while water velocity incapillary tube has little effect.Secondly, model a cooling radiant ceiling panel room without supplement of airby inner surfaces heat transfer formulation with MATLAB, which could solve thetemperature of inner surfaces which lead to the solution of inner surfaces heat transfer.The results shows that the ratio of heat transfer of cooling radiant ceiling panel andperson to the heat transfer of cooling radiant ceiling panel and the other sides of theroom is little because the viewer factor between cooling radiant ceiling panel andperson is very small. The decrease of temperature of cooling radiant ceiling panelcould increase the heat transfer of the heat transfer of cooling radiant ceiling paneland person and reduce the temperature of inner surface of out walls which lead to theimprovement of heat transfer of outside environment and inner room. The heattransfer of parts of person to the inner room shows that cooling radiant ceiling panelsystem would not cause asymmetric.Thirdly, assert the best position of the air inlet by analyzing the thermalcomfortable level of and air mean age person living zone when air inlet is at different positions as cooling radiant ceiling panel room is supplied by air. The position of airinlet lower, the air distribution better when the density of heat source is high, whilethe higher position of air inlet could not meet with the need of fresh air. The air meanage and thermal comfortable level are little related with the air inlet when the densityof heat source is low.Lastly, model a practical office in Beijing according to the actual distribution ofheat resource and simulate air distribution in the office. The results that the thermalcomfortable level and air mean age in the living zone are better are validated.Analyze the influence of the velocity and supply air temperature on indoor airdistribution, and the results shows that the difference of supply air temperature andindoor air temperature smaller, the air distribution better. The velocity of supply airhas little impact on air distribution when the supply air per unit time is constant.