A cooling system cools at least one heat producing device provided in a unit of transport, and a method is provided for cooling at least one heat producing device provided in a unit of transport. The cooling system includes at least one first liquid circuit and at least one first heat exchanger assigned to the first liquid circuit, the first liquid circuit, for cooling the at least one first heat producing device, being configured to absorb heat of the first heat producing device via a cooling liquid circulating in the first liquid circuit and dissipate heat to the first heat exchanger, the first heat exchanger being coupled in such a manner to a first air-guiding system available on board the unit of transport, that exhaust air extracted from the first air-guiding system can be supplied to the first heat exchanger in order to recool the cooling liquid.