Heat exchanger (100;200;300) for heat exchange between a first medium and a second medium, comprising a main inlet (101;201;301) for the first medium; a main outlet (102;202;302) for the first medium; and a plurality of heat exchanging plates (110;210;310;410;510;610), which plates (110;210;310;410;510;610) are associated with a respective substantially parallel main plane of extension and a height direction perpendicular to said main plane, and each of which plates (110;210;310;410;510;610) comprising a plate inlet (111;211;311;411;511;611) for the first medium, connected to the main inlet (101;201;301) for the first medium; a plate outlet (112;212;312;412;512;612) for the first medium, connected to the main outlet (102;202;302) for the first medium; and a respective first heat transfer surface (114;214;314;414;514;614) on a first side (113;213;313;413;513;613) of the plate (110;210;310;410;510;610) in question and arranged to be in contact with the first medium flowing along said first side (113;213;313;413;513;613); a respective second heat transfer surface (116;216;316;416;516;616) on a second side (115;215;315;415;515;615) of the plate (110;210;310;410;510;610) in question and arranged to be in contact with the second medium flowing along said second side (115;215;315;415;515;615); a respective plurality of indentations (120,130,140;220,230,240;320,330,340,420,430,440; 520,530,540;620,630,640) in the plate (110;210;310;410;510;610) in question, formed by the material of the plate (110;210;310;410;510;610) in question bulging out locally in the said plate height direction; wherein the plates (110;210;310;410;510;610) are fastened together in a stack on top of each other with their respective main planes substantially parallelly arranged, comprising plates of a first type (104a;204a;304a) and plates of a second type (104b;204b;304b) arranged alternatingly, whereby corresponding ones of said indentations (120,130,140;220,230,240; 320,330,340,420,430,440;520,530,540;620,630,640) of adjacent plates are arranged in direct contact with each other, so that at least one of corresponding first (114;214;314;414;514;614) and second (116;216;316;416;516;616) surfaces of adjacent plates abut each other via said indentations (120,130,140;220,230,240;320,330,340; 420,430,440;520,530,540;620,630,640) and so that flow channels (105',105",106; 205',206;305',305",306;405',405",406;505',505",506;605',605",606) for said first and second media are formed between said surfaces (114;116;214;216;314;316;414;416; 514;516;614;616), characterised in that each plate of the first type (104a;204a;304a) comprises a respective ridge-shaped indentation (120;220;320;420;520;620),arranged to form, together with a corresponding ridge-shaped indentation (120;220;320;420;520;620) of an adjacent plate of the second type (104b;204b;304b), at least one closed flow channel (105',105",205',305',305",405',405",505',505",605',605") for the first medium from the first medium plate inlet (111;211;311;411;511;611) to the first medium plate outlet (112;212;312;412;512;612), in that each plate of the first type (104a;204a;304a) comprises a respective bridge-shaped indentation (130;230;330;430;530;630), formed to comprise a through hole (132a,132b;232a,232b;332a,332b;432a,432b;532a,532b;632a,632b) through the plate in question and arranged to form, together with a corresponding bridge-shaped indentation (130;230;330;430;530;630) of an adjacent plate of the second type (104b;204b;304b), an open flow channel (106;206;306;406;506;606) for the second medium, and in that said open flow channel (106;206;306;406;506;606) communicates with corresponding open flow channels between other pairs of first (104a;204a;304a) and second type (104b;204b;304b) plates.