Natural Ventilation

[Fernando Guerrero]

Hi all! I have a question that hopefully someone here could help me!

Regarding infiltration/ventilation if you input it as Natural, does it considers wind speed of the weather file ? In case it considers it, what happens if you assign a high value for natual ventilation (in a certain zone as Bathroom) higher than possible in weather file, what does energy plus? Does not consider your value? Considers the use of a fan or any other mechanical equipment and cosequently adds its energy consumption?

Which air change rate would you consider as maximum possible regarding the occupants comfort?

Many thanks in advacne

[farhang.tahmasebi]

Hi,

a) Defining ventilation with DesignFlowRate object (with default coefficients) has nothing to do with wind speed. So, you can enter anything you want for air change rate, EnergyPlus doesn't care: garbage in, garbage out! 

You can read the I/O reference, to understand the difference between natural and other options in that field. 

b) Later you can use Air flow network module of EnergyPlus to calculate air change rate based on wind pressure coefficients.

c) As far as I can think of now, regardless of temperature changes, occupants don't have a problem with the amount of ventilation, but you cannot get as much as fresh air you want with natural ventilation. With a natural, one-sided ventilation, I am afraid you cannot get values higher that 4 ACH easily. Having cross ventilation, you may count on it until 10 ACH. Note that these are just rough estimates to make an initial simulation model.

Best,