The invention relates to an heat exchanger element of a plate type, with one internal flow passage, comprising two plates defining an inlet, an outlet and an internal passage extending between said inlet and said outlet, whereas said passage is between two generally parallel plates of self supporting polymer material. The present invention also relates to the use of such an exchanger element as collector in a solar energy arrangement, as chilled beam, as hear distributing element, as subterranean collector, as exchange element in industrial processes and as heat absorber in arrangements for cooling electrical components that are negatively affected by being close to elements having electrical conductivity.