Heating, steam generating, refrigerating, drying, humidifying, dehumidifying and ventilating apparatus, namely, Heating units for industrial purposes, Steam generators, Industrial humidifiers, Refrigerating machines and installations, Clothes drying machines; apparatus for producing hot and cold water, namely, Hot water heaters, Water heaters, Water coolers; fresh air supply apparatus, namely, air-conditioning, air cooling and ventilation apparatus; heat recovery apparatus, namely, heat recov...