Definitions

A recuperator transfers heat through a wall between two continuous streams (a plate or tube exchanger). A regenerator stores heat in a matrix that alternates between hot and cold streams (a rotary wheel is the common example).

Comparison

• Recuperator: streams never mix, steady output, simple
• Regenerator: higher effectiveness, but slight carryover between streams

In HVAC

Most air-to-air units are recuperators (plate/heat pipe) or regenerative wheels. The choice echoes the plate-vs-rotary decision: isolation versus peak performance.