Ground air supply system
2019-03-16
Since carbon dioxide is heavier than air, the lower the oxygen content is, the closer it is to the ground. From the perspective of energy saving, installing the fresh air system on the ground will give better ventilation. The cold air sent from the air vent or the upper air vent of the floor or wall diffuses on the floor surface to form an organized airflow structure; and a buoyant wake is formed around the heat source to remove heat. Because the wind speed is low, the airflow tissue is turbulent and smooth, and there is no large eddy current. Therefore, the air temperature in the indoor working area is relatively uniform in the horizontal direction, and in the vertical direction, the layer height is higher, which is more obvious. The upward wake generated by the heat source not only takes away the heat load, but also brings the dirty air from the work area to the upper part of the room, and is discharged by the exhaust vent provided at the top. The fresh air sent by the bottom tuyere, residual heat and pollutants move upward under the driving force of buoyancy and airflow organization, so the ground air fresh air system can provide good air quality in the indoor working area.Although the ground supply has certain advantages, it also has certain applicable conditions. Generally applicable to places where the source of pollution is related to the heat source, and the layer height is not less than 2.5m, at which time the dirty air is easily taken away by the buoyancy wake; there is also an upper limit to the design cooling load of the room. Research shows that if there is enough If the space is large and the air distribution device is used, the cold load of the room can reach 120w/m2, the room cooling load is too large, the power consumption of the replacement ventilation will be significantly increased, and the economy will be declining; in addition, the ground air supply device occupies space and takes up space. The contradiction is also more prominent.
It can be seen that depending on the installation environment of the fresh air system, the fresh air system selected will have some differences. Only the fresh air system suitable for the home can be selected to achieve the best exchange air effect.
Positive pressure air supply, the principle is mainly to directly send the wind into the room through power. According to experts, this system is theoretically not much of a problem, but its convection is poor.
In another form of negative pressure ventilation, the air is taken out by the exhaust fan, and the air in the room is taken out, so that the indoor air pressure is lower than the outdoor air pressure, and the outside air automatically enters the space under the atmospheric pressure, thereby forming an orientation in the space. Stable airflow belt. Its characteristics are mainly airflow orientation, stability, and internal circulation rather than internal circulation in space.
