Fresh air volume refers to the amount of air passing through an air-conditioned room per unit time, usually measured in cubic meters per hour (m3/h). Fresh air volume is a crucial parameter for assessing indoor air quality, playing a significant role in ensuring comfort, health, and energy efficiency indoors.

Calculation method of fresh air volume
The calculation of fresh air volume is mainly based on the following factors: room volume, number of personnel, equipment heat output, outdoor meteorological parameters, etc. The following is a commonly used method for calculating fresh air volume:
1. Calculate the fresh air volume according to the room volume
According to relevant national standards, the amount of fresh air required per person per hour in public places should not be less than 30m³. Therefore, the volume of fresh air can be calculated according to the volume of the room and the number of personnel. The calculation formula is as follows:
Fresh air volume (L) = room volume (V) × air changes (N)
Among them, the number of air exchanges depends on the specific use place and needs, and the number of air exchanges in general public places is about 6-8 times/hour. For densely populated places, such as meeting rooms, auditoriums, etc., the number of air changes can be appropriately increased.
2. Consider other factors to adjust the fresh air volume
In addition to the volume of the room and the number of personnel, it is also necessary to consider the impact of other factors on the fresh air volume, such as the heat output of the equipment, outdoor meteorological parameters, etc. These factors may lead to changes in the demand for fresh air volume and need to be adjusted according to the actual situation.
(1) Equipment heat: If there is a large amount of equipment heating in the room, it is necessary to appropriately increase the amount of fresh air to maintain the comfort of indoor air.
(2) Outdoor meteorological parameters: outdoor temperature, humidity, air quality and other factors will also affect the demand for indoor fresh air volume. In the cold winter, it is necessary to appropriately reduce the volume of fresh air to reduce heat loss; In areas with poor air quality, it is necessary to increase the volume of fresh air to discharge indoor pollutants.

Third, precautions for fresh air volume calculation

1. Accurately measure the volume of the room: The measurement of the volume of the room should be accurate, including the area of the wall, ceiling and floor and the height of the room.
2. Consider the density of personnel and activities: the density of personnel and activities in different places are different, and the number of air changes needs to be determined according to the actual situation.
3. Comprehensive consideration of other factors: In addition to the volume of the room and the number of personnel, it is also necessary to consider the impact of equipment heat output, outdoor meteorological parameters and other factors on the fresh air volume.
4. Follow the relevant national standards: the calculation of fresh air volume should follow the relevant national standards to ensure the quality and comfort of indoor air.
Iv. Summary
Fresh air system calculation of fresh air volume is an important step to ensure indoor air quality. By accurately measuring the volume of the room, taking into account the number of people and activities, and other factors, a reasonable amount of fresh air can be calculated. In practical applications, it is also necessary to adjust according to the specific situation to ensure the comfort, health and energy saving of indoor air. At the same time, the calculation and design of fresh air volume in accordance with relevant national standards can ensure the quality of indoor air and people's health.