The method involves a core being formed by connected pipes in several levels and end plates being connected via ribs on one or both sides. An end plate has a projecting section, with at least one curved edge extending in longitudinal direction from an outer or inner surface. The core consists of first pipe elements with a pair of tanks, connected by a heat exchanger medium channel, and the tanks connected to neighbouring tanks. A second similar element has one tank not connected to a neighbouring tank and so as to act as a divider plate. Third pipe elements have an intake/discharge element on one tank. Tanks and channel of a fourth element have a capacity for an exchanger medium, which is half the size of the first pipe element capacity.
