I manage a small deli (240 sqf...yep, that smALL) we have an 8' exhaust hood with no make up air. in the winter i ran an 6" round flex duct for make up air because it was sucking in too much cold air from underneath the door.
we have a 24,000 btu window unit which barely keeps up. I was thinking with the proper amount of make up air the exhaust will not suck out the conditioned air from the front half of the shop.
does this make any sense? and is a simple piece of 6" duct enough for the job or do i need a fan blowing air IN for this to work?