I have a conventional ducted heat pump system in my shop. It is in the basement. My dust collector will soon be moved to the basement as well. The basement is heated and cooled by the central system. I had a thought that maybe I could allow the HVAC’s return air to serve as the DC’s return. I need to add a downstairs return on the HVAC. One was not provided in the original HVAC installation. I could design it sufficiently large to return the DC air as well. So DC air would flow into the lower return and return upstairs going both backward through the upstairs return and forward through the air handler and duct system. Need to compute return flows and pressure drops for cases where HVAC is off and on. Math is fun.
My goal is to reduce the number of large holes in my floor. First holes are ugly. Second, it is hard to find any sort of grate that would allow a lot of air flow and be strong enough for tools to roll over it.