The Analysis And Research On The Influence Of Bodies Thermal Comfort In The Desktop Air Supplying System

With the development and improvement of productivity and people's living style, 90% of the time is spent staying inside the building by people. As a result, indoor environmental quality directly affects the thermal comfort, health and efficiency of the occupant. Due to the individual differences of physiological and psychological responses, clothing insulation and activity, as well as the preference to air temperature and movement and so on, the comfort demanded by different people within the occupied zone is different. The traditional whole-space air-conditioning principles (mixing and displacement) could establish a uniform environment within the occupied zone of rooms, but they are unable to provide each of the occupants with acceptable thermal sensation and air quality. However, by providing each occupant with the possibility to control his/her own preferred individual air supply, most of the occupants may accept such environmental conditions.The approach of the research in this paper includes field measure, questionnaire survey and CFD simulation. The objective of this paper is to study the supply air character and the body's response of the desktop individual air supply.Firstly, according to the comparing of different air supplying systems, two double deflection grilles put on the desk were selected as the air terminal device. The temperature and the air speed were measured respectively in three sites which is 0.5m, 0.8m and 1.2m away from the supply air outlets. The data were also measured as above under the condition of two different angles (150°and 120°) between two outlets. By analyzing the distribution of the temperature and the air speed under these air supplying conditions, it was found that the air terminal device could be satisfied in the desktop individual air supplying system by using two double deflection grilles.Moreover, in order to obtain the acceptance degree of thermal environment of desktop air supply system, 25 students from Hunan University were selected as the subjests. Each of the subjects participated in experiments at different environmental conditions. Different air temperature (26℃and 28℃) and several air speed level(0.35m/s and 0.45m/s) were studied in the experiments. The subjects were asked to evaluate the acceptance of the temperature, ralative humidity, air speed, IAQ and the general thermal sensation, local thermal sensation in the occupied zone of room. The results indicated that most of the subjects could accept the condition of the temperature, ralative humidity, etc. The minority complaint the larger temperature difference between the feet and head. But the majority could feel a strong draught sensation around the head and nick position. The importance should be attracted on how to reduce the air flow and the draught sensation around people's body in the later desktop individual air supply studies.The software Airpak is applied to simulate the desktop air supplying system. The distribution of temperature, air velocity and mean age of air in the working place and its background are simulated when the temperature and velocity of the supplying air are 26℃and 0.35m/s respectively. The results shows that the simulated temperture and air velocity are similar to the experiment data.