Numerical Simulation Study Of Improving The Thermal Comfort Of Displacement Ventilation

Displacement ventilation is a completely new ventilation way, which aims such as gaining higher air quality, economizing energy and getting better ventilation efficiency are realized. But research on it in our country is still quite limited, it is impossible to arrange air diffuser at bottom of room in some occasion, or when heat source have large quantity of heat, the height of the thermal delamination will fall down and upright temperature gradient in the lower place will enlarge, so the hot comfort of the room is not so good.In this thesis, by the way of the numerical simulation, changes of locations of diffuser vent, outlet vent, changes of locations and height of heat source and take the single heat source apart into two are simulated and researched. Analyzed what can these impact on hot comfort in room, so these can offer the gist for the design of displacement ventilation (DV). The mostly conclusion as follows:â‘ When local the diffuser of displacement ventilation to the wall on the top of the room, the air of inlet can taking advantage of Coanda effect of side vertical wall to air jets, that can produce phenomenon of air pool, more air jets can mix with air in room when enhance the height of the air inlet. Although these can reduce the temperature gradient at the lower place, these can increase wind speed at workaround and can weaken the phenomena of thermal delamination. Both can reduce the temperature gradient at the lower place and increase the height of thermal delamination when locate the diffuser at proper height, so that advance the hot comfort. The effect of hot comfort are almost the same compare the ventilation of diffuser at the lower place of getting out the air by side when the in-air velocity is 1.5m/s with diffuser attach to the vertical wall at the distance of 1.5m to the floor when the in-air velocity is 1.0m/s, so confirm the effect of saving the energy when change the diffuser.â‘¡When alter the height of diffuser, the location of out-air vent and heat source, the distributing of speed and temperature change lightly at part, so this have a little influence on hot comfort.â‘¢At the condition of unaltered the quantity of heat, when increase the height of heat source can reduce the mix extent of heat air with the other at the lower place of the room, and increase the height of the thermal delamination, also reduce the upright temperature gradient at the lower place, which can advance the hot comfort.â‘£At the condition of unaltered the quantity of heat, apart one heat source into two which enhance the quality of dispersed, that can enhance the mix range of heat air with air in the room, so reduce the height of the thermal delamination and increase the upright temperature gradient at the lower place, so reduce the effect of hot comfort.