Study on Experimentation of Comfort and Simulation of Air Distribution for Desktop-based Task-ambient Air Conditioning
|School||Dalian University of Technology|
|Course||Heating,Gas Supply, Ventilation and Air Conditioning Engineering|
|Keywords||Task-ambient air conditioning Thermal sensation PMV Energy using coefficient Personal exposure effectiveness|
At present, the traditional air conditioning targets to the whole room as the adjusting object, do it’s best to create a stable thermal environment, this environment targets neutral thermal sensation as the goal. However, long time life in this kind of comfortable environment, the human realized has problems such as sick building. Task-ambient air conditioning (TAC) has gain concern for the comfort, healthy and energy saving. This research bases on subjective experiment and CFD technique to investigate the thermal comfort and air distribution of desktop-based task-ambient air conditioning room.In the laboratory that with desktop-based task-ambient air conditioning, has carried on the subjective evaluation experiment for indoor thermal environment, has analyzed the in front of body sensation and back of body sensation to the general thermal sensation influence. The result shows that the in front of body sensation has remarkable influence to the general thermal sensation than the back and summarizes these and the entire volumetric heat feeling linear fitting formula. In the comfortable experiment at ambient area, when ambient area temperature is 28℃, in 30 minutes of the experiment carries on, human body has not appeared uncomfortable and actual thermal sensation obviously to be lower than PMV that under the stable state in the first 15 minutes of enters ambient area. When ambient area temperature is 30℃, TSV approaches in 2.0, therefore is easy to cause uncpmfortabl, the thermal sensation when enter ambient area also effected by the thermal sensation in task area. When thermal sensation approaches to neutrality in task area, the thermal sensation in ambient have hysteresis obviously. Therefore, suggested the temperature of task area does not surpass 28 ℃ for to be suitableThermal comfort, energy using coefficient and personal exposure effectiveness under the TAC run in company with background air conditioning was investigated by CFD commercial software PHOENICS. In view of the cooling load mainly brought by equipment, attendant and lamp light, when background air conditioning supply air parameter according to room in 28℃ designs, in view of 14℃~22℃ of TAC supply air temperature, flow rate should in 20m~3/h~100m~3/h, but different TAC supply air temperature corresponding flow rate has the difference. The result also show that, the energy using coefficient will be increased firstly and then decreased with the enhancement of flow rate, personal exposure effectiveness along with the amount of flow rate increase can increasing remarkable, but when the flow rate exceed 80m~3/h, the tendencyof personal exposure effectiveness which increases along with flow rate changes slow, if the flow rate is increased at this point, it will do little to better the indoor air quality. When TAC alone run, the excessive low supply air temperature can create oversized temperature difference between head and foot in ambient area. Therefore the result suggest uses 18°C above of supply air temperature, in view of 18"C~22°Cof supply air temperature, flow rate should in 109m3/h~270m3/h, but different TAC supply air temperature corresponding flow rate has the difference. Through the above research, has provided the method and the basis for the task area comfort evaluate and TAC system design.