The required fresh air volume per person: (take the required fresh air volume per person q = 30 (m3/h));

Total fresh air volume: q1= n× q = 25× 30 = 750 (m3/h);

Calculation of indoor fresh air exchange rate: [Take the fresh air exchange rate dial p=4 (times /h)], then the fresh air volume Q2 = P.S.h = 4× 65× 3 = 780 (m3/h); As Q2 > Q 1, Q2 is selected as the basis for equipment selection.

2. Exhaust air volume = room volume × ventilation times. (Calculation formula of room volume: volume = length × width × height under air outlet)

Extended data:

A, fresh air system ventilation principle:

1, the fresh air system is based on sending fresh air indoors with special equipment on one side of a closed room, and then discharging it outdoors with special equipment on the other side, which will form a "fresh air flow field" indoors, thus meeting the needs of indoor fresh air ventilation.

2. The implementation scheme is as follows: a fan with high wind pressure and large flow rate is used to blow air into the room from one side by mechanical force, and the air is discharged to the outside from the other side through a specially designed exhaust fan, so that a fresh air flow field is forcibly formed in the system. At the same time of air supply, the air entering the room is filtered, disinfected, sterilized, oxygenated and preheated (in winter).

Second, the fresh air system function:

1, use outdoor fresh air to update indoor air polluted by living and living process, and make indoor air cleanliness reach a certain minimum standard level.

2, increase heat dissipation in the body to prevent discomfort caused by wet skin. This kind of ventilation can be called thermal comfort ventilation.

3. When the indoor temperature is higher than the outdoor temperature, the building components are cooled. This kind of ventilation is called cooling ventilation of buildings.