Quick calculation method of fresh air volume and exhaust air volume

• Calculated according to the number of people in the room: (applicable to divided, multiple small rooms)
• Qm=N ×qm
• N—number of people; (the number of people in a unit area can be calculated according to the volume ratio of the unit area, that is, the number of people = area × 0.8)
• Qm — fresh air volume, unit: m3/h;
• qm—the fresh air volume required by each person (generally calculated as 30-50m3/person per person).

Fresh air volume calculation method 2

Calculated according to the percentage of fresh air in the total supply air:

• Q fresh air volume = Q total delivery volume × 10 ~ 30% (applicable to areas with relatively large areas)
• The fresh air volume takes 10% to 30% of the total air supply volume

Note: The total air supply volume is the sum of the air supply volumes of multiple air conditioners carrying the cold (heat) load of the air-conditioning area.

• Calculation of exhaust air volume
• Exhaust air volume calculation method 1
• Calculated according to the number of air changes in the room: (applicable to divided, multiple small rooms)
• QExhaust air volume=N ×V
• N—Number of air changes in the room
• V—room volume

	Room type	ventilation rate		Room type	ventilation rate
1	bathroom	10 times/h	6	meeting room	12times/h
2	bathroom	8 times/h	7	Dining room	10times/h
3	Dining room	10 times/h	8	hall	5times/h
4	Canteen	8 times/h	9	KTV room	10～15times/h
5	public toilet	15～20 times/h	10	bar

• Calculation method 2 of exhaust air volume (applicable to areas with relatively large area)
• Calculated by taking 80-90% of the fresh air volume as the exhaust air volume
• Q Exhaust air volume =Q Fresh air volume × 80～90%

The case

1. In a KTV entertainment place, the room ceiling height is 2.8m, there are 50 rooms, and the area of each room is 28m2. Calculate the total new and exhaust air volume, and select the corresponding new and exhaust fans. Calculated as follows:

Qnew=20×50×50m3/h=50000m3/h
Q row=28×2.8×50×15m3/h=58800m3/h
5 sets of BFP-10D for fresh air blower
The exhaust fan uses 6 fans of 10000m3/h.

2. The total air-conditioning area of a shopping mall is 10000m2, and the unit load is 150w/m2. Calculate the total new and exhaust air volume, and select the corresponding new and exhaust fans.

use the second calculation method

1. First calculate the air conditioning cooling load of the entire shopping mall, and select the variable air volume air conditioning unit;
2. Calculate the total air supply volume from the selected variable air volume air conditioning unit;
3. Calculate the fresh air volume according to the total air supply volume;
4. Calculate the exhaust air volume according to the percentage of exhaust air and fresh air.