Need technical opinions on heat ventilation enclosure

Added second deck to Lincoln 1000. Heat in the kitchen was a problem last summer and now we have doubled the problem
Proposed solution is to create an enclosure around the ovens with powered exhaust to outside.
(No, we are not required to have UL hood in this location for gas fired oven)
Plenty of makeup air available in summer… Winter heat will be recirculated through the dining area
Concerns are about getting adequate velocity thru the ends of the enclosure to keep waste heat going up not out, while not inducing enough negative pressure to back draft the oven flues.

I have included some nominal drawings and calculated specs below, and would look forward to any tech opinions on the enclosure as planned

TIA
David

Specs:

Materials: 1/4" Backer Board over metal studs
Ventilation Rate: 1500 cfm
Free Air Space: 30 sq ft X 2 60 sq ft total
Calculated Face Velocity: 0.4 ft/sec
Available makeup air space: Summer 120 sq/ft Winter N/A

http://i150.photobucket.com/albums/s84/boattrash/tybee/Hood_Side.jpg http://i150.photobucket.com/albums/s84/boattrash/tybee/Hood_Front.jpg

Quote:Added second deck to Lincoln 1000. Heat in the kitchen was a problem last summer and now we have doubled the problem.
Proposed solution is to create an enclosure around the ovens with powered exhaust to outside.Quote

That type solution has failed in virtually every place it has been tried. The oven controls and motors get to hot in that type inclosure and failures are induced. You mention late in this memo make up air. if you were drawing air with your proposed system all that air would have to be made up.

(No, we are not required to have UL hood in this location for gas fired oven)

That rule or lack there of Is not doing you any favor. Your oven is probably expelling 20% unburned gas and a substantial amount of carbon monoxide.If you do not have a a proper hood or some other method to exhaust all the unburned gas and carbon monoxide you could be slowly administering a dose of carbon monoxide poisoning to yourself and your workers. I have a friend who had an improperly ventilated gas water heater in his home and now must spend time in a pressurized oxygen chamber for several hours on a regular bases.

Carbon Monoxide poisoning is slow silent and insidious malady that occurs when carbon monoxide is inhaled. In the case of ovens even if the flue is vented to the outside a substantial amount of carbon monoxide is expelled. If a deck oven every time the door is opened. If a conveyor oven it is blowing out the ends of the oven.

Plenty of makeup air available in summer.

That appers to indicate that you have some type of exhaust system? Do You what is it? What is the source of your make up air? If the summer make up air is not refrigerated, that is, air conditioned to a comfort able level, then that is probably contributing substantially to why it is so hot in your kitchen.

Winter heat will be recirculated through the dining area .

Air from the kitchen should not be ducted into the dining area. Proper procedure is to maintain a higher air pressure in the dining area than in the kitchen to prevent odors from seeping into the dining area. If you have a dinning area the code requires a certain amount of fresh outside air be brought in, per person, at close to room temperature. I would guess you have some type HVAC system? If so the intake fan should run constently if heat or cool is called for or not.

Concerns are about getting adequate velocity thru the ends of the enclosure to keep waste heat going up not out, while not inducing enough negative pressure to back draft the oven flues.

A well designed ventilation system would solve all your problems, What you are proposing I believe will only create more problems.

If you would send us more information we would be happy to design a proper ventilation system for your operation. No charge no obligation.

If you wish you can contact me at pizzaovens@aol.com

George Mills