A liquid circulation cooling system for electronic devices comprising pumping means (19), refrigerant liquid cooling means and a heat exchange device (17) in thermal contact with at least one heat-generating electronic device, said heat exchange device (17) comprising a channel through which flows the refrigerating liquid, said channel having a three-dimensional configuration. In a preferred embodiment of the invention, the channel is formed by the gap enclosed by two substantially conical surfaces (41-a, 46) substantially concentric to each other. The walls of the channel may be provided with turbulence inducing elements to enhance the thermal energy transfer to the refrigerating liquid. According to yet another feature of the invention, the efficiency of the thermal energy transfer is enhanced by means of an area increase of the surface in contact with the refrigerant liquid by providing unevenness in said surface. According to a further feature of the invention, said unevenness consists of concave or convex elements provided in said surface. According to another feature of the invention, in preferred embodiments the increase in thermal energy transfer is provided by turbulence- inducing elements provided in the channel through which the refrigerant liquid circulates.