The Study On The Indoor Thermal Environment Of Direct Expansion Of Radiation Air Conditioning

Comfort,health,environmental protection and energy-saving,has become the human's life conception constantly pursuing.So people take highly attention to common convection type air conditioning for high energy consumption and easy to cause the body unwell.Radiation air conditioning with the advantages of energy saving,no blowing feeling,better thermal comfort,small noise and high air quality has been recognized by the developed countries in Europe and America,and is actively promoting to worldwide.But radiation air conditioning is still in small scale application stage in China,research on related technology is not rich enough,especially the direct expansion type radiation air conditioning has not been carried out.This paper mainly analyzes from the two major systems of direct expansion of radiant air conditioning,the radiation panel system and air system.This paper analyzes the influencing factors of indoor temperature field and its variation laws through the experimental data.This paper also carries research on the direct expansion type fresh air system in detail,like the indoor thermal environment parameters of fresh air dehumidification,wind speed,influencing the fresh air dehumidification system.Finally,it uses Design Builder and Airpak software to simulate respectively the building energy consumption,thermal environment and temperature,airflow,then analyzes the results in detail.The main research contents are as follows:(1)It lays out 36 test points according to the factors that may have impact on the indoor temperature field and analyzes the factors to the degree of affecting temperature field in the vertical face and the horizontal face.The temperature field' uniformity is very good,in the stable phase of the system,the temperature difference is within 2? of most vertical face in direction.During the operation of the whole system,maximum of temperature difference is only for 4? appearing in the 5th test point affected by window.(2)The author of this paper tested the wind speed and wind speed of the fresh air system and studied the velocity field where the area is front of the air inlet.This paper gets the change regulation between wind speed and the distance from air inlet.Wind speed is influenced by the supply air velocity of air inlet and the Angle of the fence.The maximum wind velocity is 1.2 m/s,appearing in the place where is from the air inlet 0.2 meters away and 0.5 meters high from the ground.The minimum wind speed is 0.07 m/s,appearing in the area of out from air inlet 2.0 meters.On the whole,the wind speed of every altitude layers damps large.In the area of from air inlet 1.0meter to 2.0 meters,the wind speed's damping is much less and gradually tend to be stable.In the area of out from air inlet 2.0 meters,the wind speed tends to be stable.(3)It studies the system of the direct expansion type low temperature dehumidification and gets the dehumidifying capacity is 1.48Kg/h,the relative humidity is 71.1%during the working area,the mean temperature is 26.1?,the moisture content is 14.6 g/Kg,and the enthalpy is 62 KJ/Kg.(4)It studies the filtering effect of the direct expansion type fresh air filtration system and gets the filtering effect of the whole system,close 50%.(5)Simulating the experimental platform with Design Builder,it gets the annual energy peak appearing from May to October,the energy consumption for cooling is larger reaching 53.9%,the office facilities reaching 29.2%,the lighting reaching 10.8%.It also knows that the indoor temperature can keep in 27.5??25? summer,energy consumption of radiation air-conditioning system,energy consumption distribution,and the relevant parameter about thermal comfort.(6)Simulating temperature field and the air flow organization of indoor with Airpak,it gets the mean radiant temperature,air flow distribution in different indoor space and the wind speed of working area reaching 0.19m/s larger than the actual value.In the horizontal direction,the indoor airflow moves with counter-clockwise direction and gets together in the direction of air inlet.In the vertical direction,near the air inlet are greatly influenced by new air,other area is affected by temperature difference and circulating fan.