Inline duct heat

[refer_tech]

I am looking for answers if anybody has had success on installing a commercial gas furnace next to a large air handler used to supplement the free heat from refrigeration. Will the gas furnace work to heat the airflow when it is drawn off from a large commercial duct? It would be ducted out of the main large supply duct, through the commercial furnace and then ducted back into the large supply plenum. I don't have room for inline duct heaters line Reznor makes. Any input would be greatly appreciated!

[HVAC dawg]

I would possibly concerned with the pressure drop.:whistle:

[flange]

if you got room next to it, why not just add a real heat exchanger and power burner like a little powerflame c?

[genduct]

break in the heat exchanger will pull in the flue gas.
Not sure from your post what you have in mind