To achieve top quality in metal processing applications, all the process parameters must interact optimally. Precise and efficient thermal management is essential for reaching this goal. technotrans has developed a bespoke cooling solution for continuous horizontal casting applications for the OTTO FUCHS group with headquarters in Meinerzhagen.
The resulting 2 MW cooling system offers outstanding operational reliability thanks to a combination of various technical measures, thereby enabling energy savings of 70-80% compared to conventional solutions.
OTTO FUCHS Meinerzhagen
OTTO FUCHS KG, founded in 1910 as a brass foundry, is now an internationally leading company in the non-ferrous metal industry with sites in Germany, Hungary, China, South America and the US.
In 2019, OTTO FUCHS invested in an expansion of the foundry in Meinerzhagen in order to increase the production capacity.
With the new system, OTTO FUCHS produces rods with diameters ranging from 40 mm to 82 mm and with lengths up to 7 m with two different aluminium alloys.
The foundry produces these rods exclusively for further in-house processing.
A special feature of the expansion is the use of a casting process that is new to OTTO FUCHS: horizontal continuous casting. The advantage of this method is that rods with smaller diameters can also be cast in an economically viable manner: "The omission of certain steps, e.g. subsequent homogenisation, cutting, heating and extrusion, enables us to work faster and in a particularly efficient manner in terms of the material and costs," says Victoria Gebhardt, project engineer at the OTTO FUCHS foundry.
For continuous horizontal casting, the cooling system and water quality play a crucial role which is why OTTO FUCHS relies on a bespoke system developed by technotrans solutions GmbH. The two companies have been working together for more than 25 years in Meinerzhagen. Of the more than 50 joint projects to date, the cooling system for the new foundry is the largest order – with an order volume in the seven-figure range – that the specialist for thermal management solutions has realised for OTTO FUCHS so far.
In addition, there is no need for registration and regular inspection of the system by experts as per the German 42nd Federal Immission Control Ordinance for the Protection against Legionella from Evaporative Cooling Systems, Cooling Towers and Wet Separators (42. BImSchV).
Supply project engineer
at OTTO FUCHS.
The technotrans cooling system is a container solution of 22 x 6 x 7 m with a cooling output of 2 MW. For comparison: A standard single-family house has a heating requirement of approximately 8-9 kW. Thanks to the installation of free coolers on the roof of the system, which generate cold using the outside air, the system is particularly energy-efficient, explains Fabian Heuel, sales division manager and member of the management board of technotrans solutions GmbH: "The operating cost calculation carried out in advance proves that OTTO FUCHS saves approximately 70-80% of energy with our system compared to standard concepts on the market, depending on the level of utilisation." The technotrans solution can provide the full cooling capacity for a large part of the year without having to rely on refrigeration compressors.
The risk minimisation realised by technotrans is also very impressive: "In terms of its operational reliability, the system is really one of a kind," explains Heuel. "All pumps and other relevant units are provided in a redundant setup. Even during a power failure, the supply pumps for the casting process continue to operate so that the product can still be cooled briefly." A supplied spare parts kit provides additional reassurance.
The system includes two circuits: The casting circuit, where cooling water is sprayed onto the casting, is separated from the recooling circuit by way of a heat exchanger to prevent any process-related contamination. This is necessary as the casting circuit is an open system that comes into contact with oxygen so that the water needs to be filtered and prepared accordingly. The casting circuit includes two filter units: A full-flow filter with an automatic backflush function and a secondary filter at the water basin for the continuous removal of small particles. "This ensures a constant, high water quality which is essential for the casting process. In addition, this recirculation concept helps us to reduce our water consumption," says Heuel. Contaminated water distorts the spray pattern. The casting circuit also uses frequency-controlled pumps for keeping the required pressure constant and for saving energy.
The second circuit is a recooling circuit with pressure blanketing. This circuit supplies the heat exchanger of the casting circuit and several other connected units, e.g. the electrical system of the furnace cooling system, hydraulic units and the workshop extraction system. "The recooling circuit uses an intelligent interconnection of different system components: As long as the ambient temperature is sufficiently low, the system solely relies on the free cooling concept. When this is no longer feasible, two large refrigeration units are activated one after the other in a stepless manner, at first to support the free cooling system and then, when the ambient temperature is too high, to provide the full cooling output," explains Heuel. Unlike their competitors, technotrans manufactures the refrigeration units in-house and equips them with a special energy-saving module. The smart temperature control system of this module ensures that the machines operate with optimum efficiency at all times. "Simply put: The refrigeration units only operate at lower efficiency levels during peak summer temperatures. When the temperature is low, they control their output automatically in line with the process requirements and ambient temperature," says Heuel.
Quality factor: Cooling water
To achieve the desired material properties, e.g. the necessary ductility of the rods, during the continuous horizontal casting process, the cooling water is a crucial factor, says Gebhardt. "This new casting technology is sensitive with regard to external influences which have a direct effect on the quality. This is why compliance with very strict tolerances in terms of the organic constituents, conductivity, pressure and temperature of the water is absolutely essential." The continuous casting process applied by OTTO FUCHS runs for 24-36 hours straight without interruption. Contaminated water would cause lime to deposit at the outlets of the mould. As a result, the water jet would be dispersed, thereby negatively affecting the surface quality of the cast rods. These problems are excluded thanks to the special filtration of the water in the system.
Quality factor: Construction
For this project, the quality requirements specified by OTTO FUCHS extend down to the smallest detail: To ensure optimum hygiene and stability, all the pipes are made of stainless steel. In addition, there is a lot of free space inside the container to ensure unhindered access to the individual components, thereby facilitating their maintenance.
Data reading & remote maintenance
technotrans is also very excited, says Heuel: "We really enjoyed the project. Not only because it is the most extensive project realised for OTTO FUCHS so far, but also because everything involves a very high level of technical expertise and we were able to truly implement a state-of-the-art solution without any compromises."
Moreover, the features of the system ensure that every single parameter, e.g. the temperature or cooling output, can be read out and transferred to the OTTO FUCHS control room. technotrans can also access the system remotely for servicing from their Meinerzhagen site which results in particularly short response times.
Fabian Heuel Division manager sales and member of the management board of technotrans solutions GmbH
Nico Küls Managing director of the technotrans solutions GmbH
technotrans and OTTO FUCHS were able to complete the project within the preplanned time frame despite a very difficult situation caused by the beginning of the COVID-19 pandemic right when the project entered its most crucial phase. "This situation remained present during the entire project and proved to be rather challenging, especially in terms of the interruption of supply chains and the resulting problems concerning the procurement of certain components," says Nico Küls, managing director of technotrans solutions GmbH.
The successful and fast completion of the project was made possible in particular by the close and well-coordinated cooperation between OTTO FUCHS and technotrans over many years. This aspect is confirmed by Florian Franze from OTTO FUCHS: "With technotrans, the whole package is simply right – from both companies being located in Meinerzhagen and the fast consultations up to the trustful cooperation. We are highly satisfied with the system."