My HVAC system consists of a fan, furnace, compressor-driven AC, and evaporative cooler. The problem is that there is a large air volume used only by the evaporative cooler that is generating a lot of turbulence as air flows by (think blowing over an open bottle).
I want to install a damper to close off this useless and turbulent air volume when the evaporative cooler is not running.
My question is: Can a (motorized?) damper be installed within the existing ductwork? Does such a device exist? Or does the motor always have to be external to the ductwork, and thus I have to remove some ductwork to install a damper? Is there a non-motorized, manually-operated damper that can be installed within the existing ductwork?
The ductwork is rectangular sheet-metal ductwork, about 2ft by 2ft cross section (not sure on terminology), perhaps 2-3ft high.
I am open to other ideas on how to close off this air volume.
A schematic is shown below:
After installing a damper. Preferably this damper is motorized and electronically-controllable.