The factory where the absorbers are manufactured is based on two new technologies, i.e. ultrasonic welding for copper absorbers and laser welding for aluminium absorbers. Joining of sheet with absorber piping without additional fi ller metal provides for maximum mechanical strength of the connection. According to the tests, the highest heat transmission is provided by the two above-mentioned technologies, where the contact of the absorber’s plates with its pipes takes place through the base material (copper-copper, aluminium-copper, aluminiumaluminium). The previously widely used absorber soldering technology required increasing the contact area between the sheet and piping, to ensure transfer of heat through the fi ller metal with up to 8 times lower thermal conductivity as compared to copper.