Do I call an HVAC professional for dryer duct work? I am on the bottom floor of a condo tower. I don't know where the dryer vent pipe goes but there is an opening in the duct work that is not closed and the lint has accumulated in the ceiling. Yellow arrows in the pic point to the 12x12 inch opening. The dryer is/was vented to the pipe that you see to the right of the orange pipe. I expect with the hold in the duct the pipe may be serving no purpose.However, plenty of lint is collected int the lint filter. I am waiting for condo folks to get back to me. Thanks for any advice.

Trying to put A/C in an older home that never had it or duct work. Home is 2600 sqft. I'm very limited in duct size and how it runs. The best I can do is to build a bulkhead (to house the ducting) along a center wall attached to the ceiling. Regarding CFM, the biggest the bulkhead can be is 12"X7" would that be large enough to move enough air for that size house? thanks