A brazed plate heat exchanger comprising a plurality of rectangular first and second heat exchanger plates (110, 120), wherein the first heat exchanger plates are formed with a first pattern of ridges and grooves, and the second heat exchanger plates are formed with a second pattern of ridges and grooves providing contact points between at least some crossing ridges and grooves of neighbouring plates under formation of interplate flow channels for fluids to exchange heat, said interplate flow channels being in selective fluid communication through port openings, the first pattern of ridges and grooves is different from the second pattern of ridges and grooves, so that an interplate flow channel volume on one side of the first heat exchanger plates is different from the interplate flow channel volume on the opposite side of the first heat exchanger plates, at least some of the ridges and grooves of the first pattern extend in a first angle ( to a short side of the heat exchanger plates, and at least some of the ridges and grooves of the second pattern extend in a second angle (β2) to a short side of the heat exchanger plates, wherein the second angle (β2) is different from the first angle (, characterised in that the first and second patterns of ridges and grooves are corrugated patterns of obliquely extending straight lines or said first pattern is a first herringbone pattern and said second pattern is a second herringbone pattern, the grooves of the first heat exchanger plates are formed with identical corrugation depth, wherein first grooves (G2a) of the second heat exchanger plates are formed with a first depth (D2a), and second grooves (G2b) of the second heat exchanger plates are formed with a second depth (D2b) different from the first depth (D2a), and brazing joints in and around the contact points between crossing ridges and grooves between the first and second heat exchanger plates (110, 120) are elongated and arranged in a first orientation in the interplate flow channels having bigger volume and in a second orientation in the interplate flow channels having smaller volume. at least some of the ridges and grooves of the first pattern extend in a first angle ( to a short side of the heat exchanger plates, and at least some of the ridges and grooves of the second pattern extend in a second angle (β2) to a short side of the heat exchanger plates, wherein the second angle (β2) is different from the first angle (, characterised in that the first and second patterns of ridges and grooves are corrugated patterns of obliquely extending straight lines or said first pattern is a first herringbone pattern and said second pattern is a second herringbone pattern, the grooves of the first heat exchanger plates are formed with identical corrugation depth, wherein first grooves (G2a) of the second heat exchanger plates are formed with a first depth (D2a), and second grooves (G2b) of the second heat exchanger plates are formed with a second depth (D2b) different from the first depth (D2a), and brazing joints in and around the contact points between crossing ridges and grooves between the first and second heat exchanger plates (110, 120) are elongated and arranged in a first orientation in the interplate flow channels having bigger volume and in a second orientation in the interplate flow channels having smaller volume.