| Air conditioning systems have long been indispensable in social life.With the passage of time,people have higher and higher requirements for air conditioning systems.People hope to focus more on improving human comfort on the basis of reducing building energy consumption.Radiation air-conditioning system has been extensively studied by scholars because of its advantages of high comfort,low energy consumption and environmental health.In order to avoid the condensation problem of radiant panel for radiant cooling,the independent fresh air system is generally used to bear part of the indoor cooling load and wet load.If the fresh air system adopts the form of wall attachment jet,a fresh air layer can be formed on the radiant wall to separate the radiant panel from the indoor hot and humid environment,which not only increases the convection intensity near the radiant panel but also reduces the risk of dew condensation on the radiant panel.This article mainly studies the indoor thermal and humid environment of the roof radiant cooling and Wall-Attached-Jet composite air conditioning system,and focuses on analyzing whether the temperature field,velocity field and comfort in the room under this composite air conditioning system can meet people's requirements for indoor thermal environment.For the roof radiation cooling + up supply and down return roof Wall-Attached-Jet fresh air system,the CFD simulation method is used to analyze the indoor hot and humid environment and human comfort.The minimum fresh air volume in the room is determined by the required minimum fresh air volumeper person and the number of room ventilations,The optimal cooling load between the radiant air conditioning system and the fresh air system is studied under the minimum fresh air volume and the best human thermal comfort.First,the air distribution of the fresh air Wall-Attached-Jet system is simulated at room temperature without considering the indoor cooling load.The results show that the fresh air can be covered with a layer of fresh air on the surface of the radiant roof and form a good velocity field indoors,which will not appear the phenomenon of blowing,and meet the requirements of human comfort.Then consider the case of simulated cooling load.After calculating the minimum indoor cooling load of the fresh air based on the indoor wet load and the fresh air volume of the room,the fresh air is simulated in a growth interval of 5%,from 25% of the cooling load to 45% of the cooling load.By comparing and observing the indoor temperature field and velocity field in the simulation results,the thermal comfort of the human body can be calculated,and the optimal proportion of the fresh air system to bear the cooling load was obtained according to the optimal thermal comfort of human body.Then,the position and shape of the tuyere are changed to observe the changes of indoor temperature field and velocity field and the influence on indoor human comfort.Meanwhile,the optimal load distribution ratio under different conditions is obtained according to the human thermal comfort.Finally,the range of appropriate cooling load distribution ratio of the composite air conditioning system is obtained.The results show that no matter how the position of the tuyere changes,when there is heat source in the room,the fresh air can not completely cover the whole radiant roof,and it can not completely avoid the risk of condensation of the radiant roof.At the same time,the radiation system bears 55-60% of the indoor cooling load,which is the optimal load distribution ratio.This conclusion can provide certain reference for the practical engineering application of the composite air conditioning system with radiant roof cooling and attached jet. |
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