Industrial Ovens and Vent location?

[TapNdiE]

I build large ovens for powder coating. And exhaust vent location on ovens has always been an argued topic. Some people or companies use forced air propane/gas heaters, with fans that blow 30 CFM to 1450 CFM into almost air tight ovens. These ovens range in size from 4Lx4Wx8H' to 15Lx8Wx8H'. Some ovens have the vents located near the floor on the bottom 8" somewhere on the perimeter of the oven, and others have them located on the ceiling somewhere. For combustion gases to leave the oven the best way possible without loosing too much heat in the process, I'm left wandering, Where the heck does the vent need to be located?

Please help me solve this once and for all. Hopefully I am posting this is the correct place, if not maybe some direction on where to go?
Thanks

 

[Lnewqban]

Welcome, @TapNdiE !
As long as those fans are forcing fresh combustion air in and exhaust gases out, I would say that there is no much difference.
A huge amount of combustion heat will escape with the exhaust gases either way.
The oven with the lower vents may reach and keep higher temperature of the half or third top of the interior volume.
Of course, I may be wrong.

 

[Baluncore]

For combustion gases to leave the oven the best way possible without loosing too much heat in the process, I'm left wandering, Where the heck does the vent need to be located?

I also wondered about the economy of ovens for powder coating or rotary moulding.

The fan has two jobs, to inject the required heat, and to mix and circulate the gas in the oven.

Inject combustion gasses horizontally, low down and tangentially, so they circulate as they work their way up the outside, mixing. Then they slow and circulate down in the centre around the mould or item, which is heated evenly.

Vent exhaust downwards from the bottom, where the coolest gases would stagnate.

 

[tonyt]

I build large ovens for powder coating. And exhaust vent location on ovens has always been an argued topic. Some people or companies use forced air propane/gas heaters, with fans that blow 30 CFM to 1450 CFM into almost air tight ovens. These ovens range in size from 4Lx4Wx8H' to 15Lx8Wx8H'. Some ovens have the vents located near the floor on the bottom 8" somewhere on the perimeter of the oven, and others have them located on the ceiling somewhere. For combustion gases to leave the oven the best way possible without loosing too much heat in the process, I'm left wandering, Where the heck does the vent need to be located?

Please help me solve this once and for all. Hopefully I am posting this is the correct place, if not maybe some direction on where to go?
Thanks

Hello. What did you end up with for the exhaust and how is it working for you. I am at that stage of my build.