Solar heating system

A solar water heater, comprising a solar heating system for solar heating of domestic water or of a heat transfer heating fluid comprising at least one heating element installed on the outside of a building and intended to receive solar energy for heating by heat exchange said domestic water or said heat transfer heating fluid, said heating element being in the form of a heat absorbing panel, said panel being formed of a first plate and of a second plate connected to said first plate, said first plate and said second plate being profiled symmetrically so as to form between said first plate and said second plate, outside contact zones between said first plate and said second plate, a flow channel with a fluid inlet and a fluid outlet for the passage of said domestic water or of said heat transfer heating fluid to be heated flowing in said panel, characterized in that said first plate and said second plate are stamped steel plates and are connected together by welding over all the surface of the contact zones between said first plate and said second plate, in that said weld between the plates is a laser weld, and in that a surface texture obtained by laser processing is present on at least one of said first plate and said second plate, and in that said surface texture obtained by laser processing is present on an outer surface of said first plate or said second plate of said panel, said outer surface being able to receive solar energy, said solar water heater associated with a tank for collecting heated domestic water,

• wherein said surface texture obtained by laser processing is also present on a surface in contact with said domestic water or said heat transfer fluid for heating at least one of said first plate and/or said second plate to increase the heat exchange surface area between said panel and said domestic water or said heat transfer heating fluid to be heated.