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Air curtains history
Air curtains, also known as air doors, have a long history dating back to the early 1900s. The concept of using a stream of air
James Chen
06/03/2023
Table Of Content
We all know that the air curtains can effectively maintain a perfect indoor environment and maintain a stable temperature.
But they don’t know if the air curtain is not properly designed, the air curtain is not selected according to the actual situation, make the air curtain is improperly selected (the power is too small or too small), or the installation is improper, it will lose some or all of the advantages. And it may be becomes worse than an unprotected door.
Ok, let’s discuss in this article, what factors will have a certain impact on the air curtains, and how to avoid and solve these problems, please continue to read this article.
5 factors can affect the effect of air curtain
- Air curtain selection
- The temperature differences
- The pressure differences
- Frequency of the door usage
- Internal ventilation equipment and outdoor wind
If you want to know more professional details, please join me and finish reading this post.
According to physical principles, if the door is opened, the indoor and outdoor will be a pressure difference and temperature difference between two adjacent areas.
At this time, the air between them will exchange, because this is the law of physics, they will continue to exchange until the temperature and pressure difference between the two places tend to be equal.
But most buildings will have HVACR. If there is no air curtain machine, then HVACR will work endlessly, resulting in a waste of energy.
Therefore, installing air curtains is the primary task in maintaining green buildings.
Now, we will look at the first factor that affects the effect of the air curtains
1. Air curtain selection
Want to know more about how to choose the air curtains, please refer to my other article.
Let me talk about the consequences if the air curtain is incorrectly selected.
If the air curtains are not selected correctly, the air curtain will be ineffective and even cost you money. why? We analyzed two situations.
The air curtain power is too small
If the power of the air curtain is too small, the air speed will not reach the bottom of the floor, because we require an air speed need about 2M/S at the bottom of the floor. This is qualified.
If there is no wind speed coverage at the bottom of the floor, the indoor and outdoor air will still be exchanged, so the air curtains do not have a good protective effect.
The air curtain power is too large
If the air curtains’ power is too large, the wind blowing on the ground will bounce back strongly, which will cause a turbulent flow of gas near the bottom. This will also cause the effect of the air curtain to decrease.
The power of the air curtain is correctly
When the air curtains are selected correctly, the air speed reaches the ground at 2m/s, which is the most ideal state. In this way, the environment and temperature of two different areas can be isolated very well.
2. The temperature difference
Whether in the hot summer or cold winter, we all need HVACR to provide us with a comfortable temperature. In this way, there will be a certain temperature difference between indoors and outdoor.
In some places, the temperature difference will be quite large, such as in the cold storage, indoors at minus 25 degrees, and outdoors at 30 degrees.
If you open the door, the temperature will be exchanged quickly, resulting in air transfer between two areas with temperature differences. Warm air will escape from the top of the doorway, while cold air will enter from the bottom.
Because the greater the temperature difference, the greater the air penetration and energy loss, and the greater the temperature exchange. Therefore, the greater the temperature difference, the greater the power of the air curtain should be selected.
3. Pressure difference
Generally, there will be a certain pressure difference between indoors and outdoors, but we should try to balance the pressure difference first. If there is a pressure difference, the following situations will occur:
Indoor pressure is greater than outdoor:
In this case, the pressure in the room will have a little impact on the damper produced by the air curtain. If the wind speed of the air curtain is not high enough, it will cause indoor air to escape to the outdoors. Lead to loss of indoor air conditioning/heating.
Solution: Adjust the wind guide of the air curtain to a certain angle outside and inside
Indoor pressure is less than outdoor:
When the outdoor pressure is greater than the indoor pressure, the outdoor gas will be forced into the room, causing the indoor gas to be polluted, and the indoor temperature will be unbalanced.
Solution: adjust the wind guide to a certain angle
- Frequency of the door usage
Assumption: When the door is closed, there is no temperature exchange between indoors and outdoor (actually impossible, this is just an assumption).
When the door is opened, if there is without air curtain operation, the indoor and outdoor temperatures can be exchanged freely, resulting in a lot of energy waste.
When the air curtain is operating correctly, the energy-saving can reach 80%.
Therefore, when the door is kept open and not closed, the air curtain has the longest use time, but the efficiency is not the maximum, because there is still 20% energy waste.
Solution: Install the door magnetic switch, the door opens, the air curtains operate, the door closes, and the air curtains stop operation. In this way, the efficiency of the air curtains can be maximized.
- Internal ventilation equipment and outdoor wind
When indoor ventilation equipment is running, it will change the pressure difference between indoor and outdoor.
Similarly, if there is strong wind outside, it will also affect the performance of the air curtain.
Solution: By changing the angel wind speed, the influence of these factors can be resisted. However, if the wind speed of the incoming is too high, the efficiency of the air curtain will still decrease.
5 Most Important Figures For Air Curtains
Air Jet
Optimized air duct design can bring more efficiency and save energy
Air speed
air speed depends on installation door height, which means, air speed is proportional to installation height.
Air volume
The greater the air volume, the stronger the invisible door and the better the effect
The angle of wind guide
Different occasions require different angles, and it will increase the energy-saving if the angles correctly
Fan type
Crossflow type, centrifugal, axial.
For air curtains, the centrifugal-type air curtains can create a higher-pressure jet, which means, higher air speed. The next is cross flow type, the last is axial type air curtains.
As a conclusion
When you are using the air curtains, you have also encountered some air curtains that are not so effective or the efficiency has changed. You can try to follow the above steps to do a self-test.
If there are the same factors that affect the performance of the air curtains, you can follow our suggestions and make adjustments to achieve the maximum effect of the air curtains.
If you still have problems with the efficiency of the air curtain, please contact our professional team.
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