Solar panel elements and method of manufacture thereof

摘要

Heat exchanger elements, particularly for solar panels, comprising metal tubing secured to a metal strip which is wider than the tubing and relatively thin by a weld which is metal of at least one of the tubing and the strip which has melted and cooled, the welding conditions being selected so that molten metal is expelled from between the tubing and the strip at the ends of short intervals and the strength of the weld varies longitudinally of the tubing. High frequency electric welding is used under conditions which cause the expulsion of the molten metal.