A regenerative heat exchanger for transferring heat from the exhaust gas to the intake working fluid of a prime mover. Application includes gas turbines for both motor vehicles and distributed electric generation. The heat exchanger employs a rotating matrix, which circulates through working fluid exhaust and intake channels while absorbing and rejecting heat between the two channels. Features include corrugated tubes for enhanced heat transfer, minimally welded low stress construction, quick-detach assembly of standard components, and purge flow sealing using recovered heat. Effectiveness exceeding 95% increases thermal efficiency of low-pressure ratio gas turbines.