Waste heat recovery equipment with periodic flow reversal: In which device are the flows of flue gas and air alternately reversed after fixed time intervals to store and release heat?

Introduction / Context:
High-temperature furnaces often recover waste heat to improve efficiency. Two principal devices are used: recuperators and regenerators. Understanding their operating principles is key to proper selection and design.

Given Data / Assumptions:

• Fixed-interval flow reversal is mentioned.
• Checker brick mass is commonly used for heat storage.

Concept / Approach:
A regenerator stores heat from hot exhaust in a solid matrix (checkers). After a set period, valves reverse the flow so cold combustion air passes through the hot matrix, picking up the stored heat. A recuperator, in contrast, is a continuous exchanger with separate, non-reversing passages.

Step-by-Step Solution:

Verification / Alternative check:
Industrial drawings of open hearth/coke oven systems show reversing valves feeding regenerator checkers.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming both devices behave the same; only regenerators rely on thermal storage with timed reversals.

Final Answer:
Regenerator