COOLING UNIT FOR A HEAT EXCHANGER

The invention is a cooling unit for a heat exchanger, which preferably is a heat exchanger integrated in an oxygenator for the purpose of controlling the temperature of blood conveyed in an extracorporeal blood circuit. The cooling unit has a reservoir in which a liquid is stored, a reaction vessel comprises a reactant and which, in conjunction with the liquid, is able to initiate an endothermal reaction. A fluidic access is generated between the reservoir and the reaction vessel. A fluid line extends at least in part inside the reaction vessel which has an inlet line and outlet line, which are each connectable or connected in a fluid-tight manner to a hose system of the heat exchanger, which together with the hose system of the heat exchanger, provides least part of a fluid circuit.