11 Lighting, heating, steam generating, cooking, refrigerating, drying ventilating, water supply, burner for liquid or gaseous fuels, heating systems, parts of the aforesaid goods, included in this class hot water heaters, boilers, gas boilers, heating systems, air conditioning and sanitary installations, particularly fermentation vessel (fermenter) of biogas plants, hydrogen-oxygen torch, gas generators, solar collectors and solar furnaces, heat pumps, heat recovery, thermal storage, heat exchangers not parts of machines, hot water heating systems