Thermal control device, in particular cooling device

The invention relates to a thermal conditioning device having an upper plate and a lower plate assembled with the upper plate so as to jointly form a plurality of channels (21) for a heat transfer fluid, in particular a refrigerant; the invention relates to a heat exchanger comprising a plurality of channels (24) which extend in sequence in the flow direction of a heat transfer fluid in an outflow zone in which the channels communicate with one or more fluid inlets, a reversal zone (24) in which the channels communicate with one or more fluid outlets, and a return zone in which the channels communicate with one or more fluid outlets, the reversal zone connecting the outflow zone and the return zone, such that at least some of the channels are substantially U-shaped in the reversal zone; according to the invention, said device comprises a part to be cooled, such as a rectangular-shaped part, the reversal zone (24) having at least one transverse channel (39) connecting the at least one channel of the outflow zo