The Numerical Simulation Research Of The Wall Radiant Cooling Air Conditioning System With Independent Fresh Air

To advocate saving and to oppose extravagance and waste, for the construction of office of the party and government, national government has repeatedly made the related standards. Relevant standard specifies the usable office area of Staff at all levels. And, most of the independent non-government office occupancy is toward miniaturization and simplification. At the same time, the radiant cooling air conditioning is a hotspot of current research. For the majority of the time the staff in the office is sitting, less time is standing. The area of the direct radiation heat transfer between the staff in these two states and the vertical wall, is larger than area of the direct radiation heat transfer between the staff in these two states and the floor(ceiling). In addition, the vertical wall area is greater than the floor and roof in small office. So the small office will use the new composite air conditioning that adopt vertical wall radiant cooling as the background and directly sent isolated outdoor air to the work place.A single office located in Xi’an in this paper adopts two kinds of air conditioning, one uses traditional air conditioning mainly by convection heat transfer, the other uses the new composite air conditioning that adopt vertical wall radiant cooling as the background and directly sent independent fresh air to the work place. Physical and geometrical model is established. Renormalization group k-ε turbulence model is used, and the software fluent is used to do the numerical simulation of office indoor air conditioning environment in the two air conditioning systems. indoor temperature field, air velocity field and thermal comfort around the office staff are be compared and analyzed in the two air conditioning systems.Simulation results show:(1)Air volume of traditional air conditioning is large, which cause indoor velocity field easily made blowing feeling. However, Radiant cooling composite air conditioning can overcome the shortcomings.(2)Traditional air conditioning design, try my best to make indoor airflow field and temperature field uniform, and let the fresh air mixed with indoor old air fully. So that caused the air by breathing no longer is fresh. However, Radiant cooling composite air conditioning in this paper, it directly sends the fresh air to the breathing zone, which makes the indoor staff can breathe more fresh air.(3)In radiant cooling composite air conditioning, the fresh air supply little cooling load, most of cooling load is supplied by the vertical radiation wall, and radiant cooling of cold radiating surface plays a major role.(4)By changing the position of air outlet to optimize air conditioning, it is found that layout of air outlet placed on top of hot space is help of removing indoor heat gain,thus reducing the cooling load of air conditioning.Related data and the numerical simulation study of a single office with radiant cooling composite air conditioning show, under the condition of good design, the new composite air conditioning that adopt vertical wall radiant cooling as the background and directly sent isolated outdoor air to the work place is better than traditional air conditioning mainly by convection heat transfer, it is a better way of air conditioning, and can create comfortable indoor air environment for the simplify small office.