HEAT RECOVERY UNIT

A compact heat recovery unit which includes separate and distinct thermal cores housed in their own channels. Each thermal core and its respective channel is moved at intervals. When a thermal core and its channel is inserted into a high temperature fluid flow, the thermal core absorbs the heat. When this heated thermal core and its channel is then later inserted into a low temperature fluid flow, the low temperature fluid is preheated by the heated thermal core. This operation is repeated with at least two independent thermal cores and their respective channels to maintain substantially continual pre-heating of received low temperature fluid. Similarly, the compact heat recovery unit can be used in a cooling application where pre-cooling of received higher temperature fluid is executed.