Heating with waste heat
Compressed air is the driving force required in the manufacturing process to enable the operation of valves and the working of machines. Here at MANN & SCHRÖDER COSMETICS we work with compressors to produce compressed air.
There are three compressors at our Hüffenhardt site working at 300 HP to generate the compressed air required. Air is sucked in by the compressors, compressed and released into our piping system in compressed form. The compressing process generates very large quantities of heat. This heat usually has to be exchanged with outside air in order to cool the compressors down.
We make use of this heat by means of heat recovery processes. Our compressor system is fitted with a water cooling unit for this purpose with a heat exchanger connected to the heating network. Cold tap water with added antifreeze is routed through the hot compressors and heated there to 50 degrees. The hot water is pumped into the radiators throughout the building and heats the rooms. The remaining cold water flows back into the compressors where it is reheated.
“The water-cooled compressors were put into operation in Hüffenhardt in January 2017,” said maintenance manager Stefan Martin, “and not one single litre of heating oil was used all year – the waste heat from the compressors is enough to heat the entire building.”The eco-friendly and resource-efficient solution has two immediate benefits. Firstly, around 40,000 litres of heating oil can be saved every year, and secondly, no extra energy is required to cool the compressors thanks to the integrated water cooling system.
“The heat which is given off during the generation of compressed air is nothing more than a by-product which we use to our advantage without incurring any costs,” continued Stefan Martin. “Any waste heat which is not used needs to be cooled down before it is discharged, necessitating yet another process of generating energy.”
This is still the case in the summer at present when the buildings are not heated. At this time we use some of the heat to produce hot water for various jobs, such as cleaning small parts.
We have had existing compressors at our production site in Siegelsbach retrofitted with heat recovery systems and have been working with this environmentally friendly solution since the end of 2017.