Method and system for heat transfer for a vehicle

For heat transfer in a vehicle (10), a heat-transporting transfer medium is pumped in a first flow direction (13) in order to exchange heat between a first device (1) of the vehicle (10) and a second device (6) of the vehicle (10). By contrast, the transfer medium is pumped in a second flow direction (14), which is directed opposite to the first flow direction (13), in order to exchange heat between the first device (1) and a third device (4) of the vehicle (10) which is different from the second device (6).