Why did the fresh air system replace the exhaust fan?

Update:15-02-2019
Summary:

First of all, the exhaust fan can only achieve local sh […]

First of all, the exhaust fan can only achieve local short-term exhaust, without a reasonable pressure field and airflow path, so that the true sense of air replacement cannot be achieved. The fresh air system is reasonable to organize the indoor airflow through the air supply port and the air outlet, so that the indoor air can flow in a long time, and the air including the indoor dead angle can also be circulated, so that the purpose of air replacement can be continuously operated for 24 hours.

The exhaust fan is very noisy because the exhaust fan motor has a large power and a large air volume. It will generate a lot of noise in a short time. If it is opened for a long time, it will cause environmental noise pollution. However, because the air volume of the fresh air system is reasonable, the noise is small, and it is enclosed in the ceiling space, it blocks the transmission of noise, does not affect people, and can be opened to the minimum level at night to achieve 24-hour ventilation.

The exhaust fan can only extract the air from the room, so the time is a little longer, the room will form a negative pressure state, the room will be deprived of oxygen, and the person will feel uncomfortable when staying. The fresh air system can eliminate the dirty air. Bring fresh outdoor air, and the incoming air is filtered and purified to make it breathe more smoothly.

The panel of the exhaust fan is relatively large, and if each room is installed, it will affect the beauty of the room. However, the fresh air system only has a ventilation port and a return air outlet in each room, which will not affect the overall decoration of the room.