Simulation On Task Conditioning In Offices

Task air conditioning system is a personalized ventilation method. It divided the indoor environment into work zone and background zone. The task air conditioning focuses on the thermal environment of the work zone near people while the background air conditioning controls the temperature and humidity of the whole room. Task air conditioning system can provide thermal comfort to a person as well as sending the fresh air to breathing zone directly. In this way, the breathing air quanlity is better and the fresh air volume rate is less which promises more energy is saved. In this paper, the Airpak software is used to set a mathematical model and research the impact on the thermal environment and indoor air quality of task air conditioning.The results show that compared to other kinds of task air conditioning systems (ceiling-based task air conditioning, floor-based task air conditioning)and central air conditioning system, desktop-based task air conditioning system can make a more comfortable temperature and PMV field around person. The energy efficiency of this method is also higher. It can be optimized by setting the outlet on the top of the desktop-based task air conditioning room. In this way, the temperature gradient around person is decreased and more comfortable.Desktop-based task air conditioning system and central air conditioning(used as background air conditioning)system can be used together. When indoor design temperature of background air conditioning is 30℃or 32℃, thermal comfort in the room can be achieved by setting certain temperature and air flow rate through desktop-based task air conditioning. The thermal environment is different when background air conditioning method changes. It is also affected by partitions and human density of the room.Same thermal comfort level can be achieved by using central air congditioning system, desktop-based task air conditioning system and the combination use of both. However, desktop-based task air conditioning system is the most efficient method. It can also decrease the pollution density of breathing zone, increase the indoor air quanlity. Task air conditioning systems should be designed according to the characters of the office, such as human density, space usage rate and climate. As in this research, when the space usage rate is high and the passway is near the work zone, using task air conditioning without background air conditioning is appropriate.