determining the supply air needed for an indusrial room
determining the supply air needed for an indusrial room
(OP)
Hello
I am sizing a make up air unit. this is the first time I have done this.
We are only worried about heating the room.
I have calculated the following:
the air flow need for 10 air changes.
the heat loss in through the walls and roof and quantity of air needed to make up for this loss
the quantity of air need to keep the room pressurized at .05 in water.
how do I put all this info together to siz the unit?
add them all together?
do I pick the larger of the three?
Or??
thanks
Tom
I am sizing a make up air unit. this is the first time I have done this.
We are only worried about heating the room.
I have calculated the following:
the air flow need for 10 air changes.
the heat loss in through the walls and roof and quantity of air needed to make up for this loss
the quantity of air need to keep the room pressurized at .05 in water.
how do I put all this info together to siz the unit?
add them all together?
do I pick the larger of the three?
Or??
thanks
Tom





RE: determining the supply air needed for an indusrial room
Storage, process, office?
RE: determining the supply air needed for an indusrial room
10 air changes per how often? Where did this requirement come from?
the heat loss in through the walls and roof and quantity of air needed to make up for this loss
Air doesn't make up for heat loss. Air at a temperature does. Within limits you can play with the temperature.
the quantity of air need to keep the room pressurized at .05 in water.
Where did this requirement come from?
In an ideal fantasy world all of these conditions converge at a single value of air flow.
In the real world you decide which is most important, then see what that gets you for the others. Repeat until you have acceptable values for all.
RE: determining the supply air needed for an indusrial room
A simple example is a classroom with a kitchen hood. If the ventilation requirement is 400 cfm, and the hood exhausts 1000 cfm, you need to meet the makeup air requirement of the hood, then you automatically meet (exceed) the ventilation requirement
knowledge is power
RE: determining the supply air needed for an indusrial room
The 10 ACH should be secondary, don't design around it. You might find it's met after meeting needs of the above.