Heat exchanger

A method for manufacturing a modular system for heat exchange between fluids, the heat exchanger element comprising two end plates, wherein at least one end plate is configured with inlets and outlets for fluids, the modular system comprising:

• a number of heat exchanger elements and a number of guiding elements,
• wherein each heat exchanger element comprises a folded sheet material comprising a plurality of slits extending in a longitudinal direction of the folded sheet material, which longitudinal extending slits form the fluids flow paths, an outer casing being cast onto the folded sheet material forming one piece,
• wherein a central opening of the outer casing covers an outer circumference of the folded sheet material, exposing a front side and a back side of the folded sheet material where two through holes, forming the inlets and outlets for each fluid, are provided on each side opposite of the central opening of the outer casing,
• wherein each guiding element comprises two inlets and two outlets for fluids, and a bead or edge, provided on one side, forming an enclosure around the inlet and outlet for a first fluid, and a bead or edge on an opposite side, forming an enclosure around the inlet and outlet for a second fluid,
• wherein heat exchanger elements and guiding elements are arranged successively following each other, the heat exchanger elements being arranged such that two adjacent heat exchanger elements on sides facing each other carry the same fluid, wherein the method comprises:
• folding a sheet material into the folded sheet material with the plurality of slits extending parallel to the longitudinal direction of the folded sheet material,
• forming the fluids flow paths via the longitudinal extending slits, wherein a ratio between a slit width and a slit depth of each slit is less than 0.15;
• placing the folded sheet material into a mould, and
• adding a material into the mould to cast the folded sheet material and the outer casing in one piece,
• wherein the central opening of the outer casing covers an outer circumference of the folded sheet material, thereby exposing opposite sides of the folded sheet material.