Analysis On The Effect Of Opening The Window For The Indoor Thermal Environment With Radiant Cooling Ceiling

Radiant cooling ceiling has become more and more popular as a kind of energy saving air conditioning because of the emphasis on building energy conservation in society. The advantage of radiant cooling ceiling is not only the energy efficiency but also the good comfort. The main object of this paper is the indoor thermal environment with the radiant cooling ceiling. In the current study of the indoor thermal environment with radiant cooling ceiling, the main factors to consider is heat-transfer character of radiant cooling ceiling, operating temperature of the ceiling,the temperature and velocity of the air from the ventilation system. But the human factors such as opening the window or opening the door are rarely considered. This paper analyzed the effect of opening the window for the indoor thermal environment with radiant cooling ceiling.This paper first introduces the development and the research status of the radiant cooling technology, then the characteristics and the classification of radiant cooling ceiling. The paper also introduces the design methods and heat-transfer process of the radiant cooling ceiling system.The study is conducted through the experiment. The measured data in the experiment consists of the temperature of walls, the temperature of air and the humidity of air. The results show that: the temperature of indoor air changes rapidly and greatly after the window opened, and the upper air's temperature changes more severe than the lower air. The indoor thermal environment changes by the maximum extent within 5 minutes after the window opened. As time goes on, the temperature of indoor air changes more slowly, the rates are also getting smaller and smaller. The indoor thermal environment finally become stable after 55 minutes.The study is also conducted through the method of CFD simulation. A physical model of radiant cooling ceiling system room is established. The cooling load of the room is determined by load calculation. The results of simulation showed that: the upper air in the room is first affected after the window opened, and the temperature of it changes rapidly in response. The temperature of the air in the work area changes more gentlely. The heating process of air in the room has a certain directionality. It's happened from the upper part to the lower part of the room, as well as from the top of the heating body to the surround of the heating body. And the rate of temperature riseof indoor air is gradually slowed down. The upper air in room has a larger temperature gradient than the air in the work area. The temperature gradient between the human's head and ankle remains within an acceptable range. Compared with the experimental results, the temperature of the air rises to a lesser extent in simulation, which can be concluded that effect of opening the window for large room is significantly less than the small room.