Regenerative and Non-Regenerative Heat Exchangers:

Heat exchangers are also categorized through their function in a particular system. A general classification is regenerative or non regenerative. A regenerative heat exchanger is one in that the similar fluid is both the cooling fluid and the cooled fluid, as described in Figure. That is, a hot fluid leaving a system provides up its heat to "regenerate" or heat up the fluid returning to the system. Regenerative Heat Exchangers are commonly found in high temperature systems whereas a portion of the system's fluid is erased from the major process, and after that returned. Since the fluid erased from the major process holds energy (heat), the heat from the fluid leaving the main system is used to reheat (regenerate) the returning fluid alternate of being rejected to an external cooling medium to improve effectiveness. It is important to remember in which the term regenerative/nonregenerative just refers to "how" a heat exchanger functions within a system, and does not denotes any single categories (tube and shell, parallel flow, plate, counter flow, many more.).

In a nonregenerative heat exchanger, as described in Figure, the hot fluid is cooled through fluid from a separate system and the energy (heat) erased is not returned to the system.

Figure: Regenerative and Non-Regenerative Heat Exchangers