Air distribution

[Herschmidt]

I have a 4000 sq ft retail space, and there are 2 roof top units of 5 Tons each one, this place is going to be an office place, the offices have different dimensions.

My question is How do I calculate the CFM's for each office?

Thanks.

Hernan

[Andy]

I have a 4000 sq ft retail space, and there are 2 roof top units of 5 Tons each one, this place is going to be an office place, the offices have different dimensions.

My question is How do I calculate the CFM's for each office?

Thanks.

Hernan

Hi Herman
CFM will be a product of the duty required to cool the roon sensible and latent and the number of air changes/hour you require. You could have a variable air valume system where CFM varies with load

[frank]

I have a 4000 sq ft retail space, and there are 2 roof top units of 5 Tons each one, this place is going to be an office place, the offices have different dimensions.

My question is How do I calculate the CFM's for each office?

Thanks.

Hernan

If you already have the roof top units installed then your only option is to balance the system down proportionally. Work out each room volume and then calculate the room volume as a percentage of the total volume. Now balance the air flow accordingly.

Don't forget though that each room must also have a return air path back to the roof top for proper operation.

[S.K.VARDE]

You will have to calculate the heat load (in TR) of individual office blocks. Then propornate the CFM as for 1TR to 400 CFM. Don't forget to get back the return air to the unit in the same proportion. You may require redesigning of the air destribution system and balancing the same.