Why must the exhaust fan capacity in a winter cooling system be ...

[theo]

Why must the exhaust fan capacity in a winter cooling system be equal to or less than the combined pressurizing fan capacity?
 
  What will be an ideal response?

Question 2

In addition to cooling, what other uses can the fog system have in a greenhouse?
 
  What will be an ideal response?

[chjcharjto14]

Answer to Question 1

If more cold air enters through the louvers than can be picked up by the
pressurizing fans the excess will settle to the floor at the inlet end of the
greenhouse. This would result in an uneven growing temperature.

Answer to Question 2

1) It can be used in place of a mist system in a cutting propagation
greenhouse. 2) It can be used to maintain high humidity in a seed propagation
chamber to get around the deleterious need for watering.

[theo]

Excellent

[Dominic]

Thanks for the timely response, appreciate it