Recuperator
A recuperator is a heat exchanger that continuously transfers heat from a furnace's hot exhaust gas to the incoming combustion air across a metal or ceramic wall. Preheating the air reduces the fuel needed to reach process temperature.
Unlike a regenerative burner, which stores heat in a media bed and cycles, a recuperator transfers heat steadily through a separating wall so the two gas streams never mix. It is simpler and lower maintenance but achieves lower air-preheat temperatures than regenerative systems. Recuperators are common on continuous furnaces, kilns and incinerators where moderate, reliable heat recovery improves combustion efficiency.