Making sensible use of heat and cold
Villadose: Warm rooms in winter
At the Villadose plant in Italy, all offices, training rooms and the hot water for the changing rooms have already been kept warm in winter since 2014 thanks to the waste heat from the air compressors. This resulted in a saving of about 50% of the natural gas consumption that would otherwise be burned for heating. Rainer Prügl, Managing Director at the Villadose plant, says: “Minimum use of the right resources, maximum benefit without waste - that's our goal.“
Carregado: Heating for the slip tanks
At the ceramics plant in Carregado, Portugal, the waste heat from the air compressors is not used to heat the offices, but to heat the slip tanks. The preheated, liquid slip mass is cast into ceramic blanks. Of the two one-megawatt gas boilers used to heat the slurry tanks, one could be switched off in 2021. The waste heat from compressed air generation covers more than half of the energy required to heat the slip mass.
Rapperswil-Jona: Using the cold from the ambient air
To prevent production plants, such as injection moulding machines, from overheating, they need cold. The machines or their components are cooled with cooling water that is circulated in a closed circuit. The corresponding cooling water basin holds 400,000 litres of cold water. The water, which is heated to about 18 degrees Celsius in the production circuit, is cooled down to 14.5 degrees Celsius in the basin and fed back into the production circuit. However, cooling costs energy. The cooling compressors that cool the water need electricity. Three of them are in use at the Rapperswil-Jona plant.
To save energy, the Rapperswil-Jona plant taps the cold in the winter months via fans installed on the roof of the plant. As soon as the ambient temperature drops below 10 degrees Celsius, the cold ambient air is fed to the cooling water systems. In winter, therefore, practically no electrical energy is used to cool the water. Energy savings? 30% per year.