This relates to a unit for storing and releasing thermal energy including a plurality of blocks (3) each having a body (330) the lateral walls of which delimit a chamber (7) suited to receiving storage and release elements (13) of PCM type, to be placed in heat exchange relationship with a refrigerating or heat-transfer fluid (9) circulating between the chambers via passages; and elements (19) for the thermal management of the chambers arranged around said chambers and at least some of which include a thermally insulating material and others a PCM.