A heat exchanger (1; 1') comprising: at least a first group and a second group of channels arranged to provide fluid paths between a first end and a second end of said heat exchanger (1; 1'), said channels being capillary dimensioned for the used fluid and connected to each other by a first and a second fluid distribution element (11, 21) conducting fluid from predetermined channels between the different groups, a first heat transfer element arranged in a vicinity of said first end to work as an evaporator for transferring a heat load to fluid in all channels of said at least first and second groups of channels, wherein said first heat transfer element comprises a first surface for receiving electronic components and a second surface with grooves for contacting walls of said channels in order to transfer heat generated by said electronic components to said fluid in said channels, a second heat transfer element arranged in a vicinity of said second end to work as a condenser for transferring a heat load away from said fluid in all channels of said at least first and second groups of channels, a first connecting part arranged at said first end of said heat exchanger (1; 1') and which comprises the first fluid distribution element is arranged to conduct fluid from one or more predetermined channels of said first group of channels into one or more predetermined channels of said second group of channels, and a second connecting part arranged at said second end of said heat exchanger (1; 1') and which comprises the second fluid distribution element which is arranged to conduct fluid from one or more channels into one or more channels of the same group (2, 3) of channels, wherein the first and second fluid distribution elements (11, 21) consists of a plurality of plates (12 - 16; 22, 23) arranged on top of each other, some of said plates comprising openings (17, 19; 24) for providing fluid paths between channels of said at least first and second groups (2, 3) of channels. at least a first group and a second group of channels arranged to provide fluid paths between a first end and a second end of said heat exchanger (1; 1'), said channels being capillary dimensioned for the used fluid and connected to each other by a first and a second fluid distribution element (11, 21) conducting fluid from predetermined channels between the different groups, a first heat transfer element arranged in a vicinity of said first end to work as an evaporator for transferring a heat load to fluid in all channels of said at least first and second groups of channels, wherein said first heat transfer element comprises a first surface for receiving electronic components and a second surface with grooves for contacting walls of said channels in order to transfer heat generated by said electronic components to said fluid in said channels, a second heat transfer element arranged in a vicinity of said second end to work as a condenser for transferring a heat load away from said fluid in all channels of said at least first and second groups of channels, a first connecting part arranged at said first end of said heat exchanger (1; 1') and which comprises the first fluid distribution element is arranged to conduct fluid from one or more predetermined channels of said first group of channels into one or more predetermined channels of said second group of channels, and a second connecting part arranged at said second end of said heat exchanger (1; 1') and which comprises the second fluid distribution element which is arranged to conduct fluid from one or more channels into one or more channels of the same group (2, 3) of channels, wherein the first and second fluid distribution elements (11, 21) consists of a plurality of plates (12 - 16; 22, 23) arranged on top of each other, some of said plates comprising openings (17, 19; 24) for providing fluid paths between channels of said at least first and second groups (2, 3) of channels.