Ventahood fan with inline booster fan ?

[gristlehead]

So I'm out visiting my dad yesterday and he is showing me his new kitchen remodel and he starts telling me about the new ventahood 1200scfm and that he is putting an inline fan that pushes 1100scfm down the line from the ventahood. My first thought is that he just limited his 1200scfm ventahood to 1100scfm. Am I right, where can I find the formulas to prove this. Dad's a pretty sharpe guy, he had it in his head that he was effectively building a 2300scfm ventahood. I kind of need to know quick cause the electrician comes tomorrow to hook it all up.

If the ID is larger than the OD then the whole is on the outside Right?

 

[KiwiMace]

Fans in series boost pressure, not airflow. This arrangement would only flow a little more than the normal.

My biggest concern is that the inline fan motor would need to be rated for Kitchen Exhaust use, as grease buildup could potentially cause a fire. Check your local/country building or mechanical code.

 

[gristlehead]

Thanks, I just got off the phone with him, the second fan is part of the ventahood system and is rated for kitchen aplications. He seemed a little mad, apparently the salesman had him thinking that he was almost doubling the scfm being removed from the cooking area.

If the ID is larger than the OD then the whole is on the outside Right?

 

[willard3]

Fans in series, heads (pressures) add.....CFM is the same

Fans in parallel, flows (CFM) add.....head is the same

 

[AbbyNormal]

1200 CFM is an awful lot of air to be exhausting from a home. Make sure any fuel fired applicances do not back draft.

You will need a make up air system and a requirement to temper this air is a possibility

Take the "V" out of HVAC and you are left with a HAC(k) job.