Profiled joint for heat exchanger

A joint configuration for a fluid channel of a heat exchanger, comprising a joint between first and second channel portions where fluid flow is to change direction, wherein

• the first channel portion is configured to direct fluid flow in a first direction and comprises a first edge at an angle divergent from the first direction, the first edge having a first edge face;
• and
• the second channel portion is configured to direct fluid flow in a second direction which is at an angle of less than 180° relative to the first direction, the second channel portion comprising a second edge at an angle divergent from the second direction, the second edge having a second edge face;
• wherein the first edge face and the second edge face each have a depth between a respective top of the edge face and a respective bottom of the edge face and a length extending from one end of the respective edge face to the other;
• wherein the joint is a first joint between the first edge face of the first channel portion and the second edge face of the second channel portion;
• wherein at least one of the first edge face and the second edge face is concave in shape along the length of the edge face, so as to provide a gap between the first and second edge faces of the first and second channel portions;
• and
• wherein the gap between the first and second edge faces narrows towards the ends of the edge faces.