recuperator

noun

1. a person or thing that recuperates.
2. (in a recuperative furnace) a system of thin-walled ducts through which incoming air and exhausted gases pass separately so that the air is heated by the gases.

noun

1. a person that recuperates
2. a device employing springs or pneumatic power to return a gun to the firing position after the recoil
3. chemical engineering a system of flues that transfers heat from the hot gases leaving a furnace to the incoming air