Concept:
Regenerators are heat recovery chambers used in glass tank furnaces. They store heat from outgoing hot gases and use it to preheat incoming air.
Step 1: In glass melting, large tank furnaces operate continuously at high temperature.
Step 2: A large amount of heat is carried away by exhaust gases.
Step 3: Regenerators recover this heat and improve fuel efficiency.
Step 4: They are commonly associated with regenerative tank furnaces used in glass production.
Therefore, regenerators are associated with:
\[
\boxed{\text{Tank furnaces}}
\]