EN - How to work with +Active Air dehumidification

Question

How do I work with +Active Air dehumidification?

 Answer 

The outside air valve and the fans can be used during dehumidification.
They both will start at minimum position.

The dehumidification capacity has to be entered by the grower (normal between 20 and 30 g/m2/h).

The dehumification capacity is calculated like this: ( absolute humidity of the greenhouse - absolute humidity of the corridor ) x fan speed

When the calculated capacity is lower than the setpoint, then the outside air valve is opened. When this valve reaches 100% and the calculated capacity is still too low, then the fan speed wil be increased.

To get the right calculation the relation between % and m3/h has to be entered.

And the right greenhouse area  has to be entered.

Here you see that the outside air valve is opening (phase 2 = increase fan speed).

Example

The screenshot below shows the following data:

• The AH greenhouse air is 14.1 g / m3

• The AH of the intake air is 10.4 g / m3.

In other words: if we blow in 1 m3 of air, we have replaced 1 m3 of greenhouse air with 1 m3 of intake air and we have dehydrated (14.1-10.4=) 3.7 grams.

 

3.7 grams of moisture is still very rare, the screenshot below shows that the department is quite large. If we have removed a total of 3.7 grams of moisture, we have dehumidified per square meter (3.7/8000=) 0.0004625 grams. Fortunately, the fan capacity is also relatively large, and every hour we blow up 13600 m3 of air and remove So (13600x3,7=) 50320 grams of moisture per square meter is (50320/8000=) 6.29 grams of moisture, in other words the dehumidification capacity is 6.29 g/m2/h. 

 

In the screenshot below you can see that the set dehumidification capacity is 10 g/m2/h. The Active Air dehumidification program calculates (based on a fan capacity of 13600 m3/h) that there is an AH of the blowing air of 8.17 g/m3 (but after calculation). The AH of the intake air is currently 10.4 g/m3 and therefore has to go down. Active Air must blow in drier air and must therefore add more (dry) outside air. The outside air valve will be further controlled open.

When the valve is fully open (or when the maximum valve position is reached), the status goes to "phase 2 - fan" and the Active Air dehumidification program will start the fan.

• Related Articles

• EN - How to work with +Active Air valve

  Question How do I work with +Active Air valve?  Answer  The Active Air valve is used in the following situations: In the example above the valve is opened from 0 to 100% when the greenhouse temperature is from 20 to 22 (=20 + 2) °C. With the ...

• EN - How to work with +Active Air fan

  Question How do I work with +Active Air fan ?  Answer  The fan must run at a minimum speed of 40%. The Active Air fan is used in the following situations: In the example above the fan speed is from 40 to 100% when the greenhouse temperature is from ...

• EN - How to work with +Active Air in a (semi) closed greenhouse

       Question How to work with +Active Air in a (semi) closed greenhouse?  Answer  The climate settings: The standard settings ventilation temperature leeside and windside are set to 35 °C and are hidden. Cooling 1 can be a pad wall and cooling 2 can ...

• EN - How to work with +Active Air cooling

  Question How do I work with +Active Air cooling?  Answer  The pad wall can be controlled in 5 stages by the cooling program. In the example above the cooling is starting when the greenhouse temperature is higher than 22 °C. With the influence ...

• EN - How to work with +Active Air overpressure

  Question How do I work with +Active Air overpressure?  Answer  The Active Air overpressure is used in the following situations: In these situations the maximum overpressure is 15 Pa (in practice between 10 and 15). During recirculation a minimum ...