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.
Edit: If you are thinking about doing this, I would now suggest trying some stationary "guide vanes" first that allow the air underneath to pass without causing turbulence above. It's likely to have the same effect without need of any moving parts.