The "green foundry" manufactures consumer goods from metal in an energy-saving manner: no fossil gas is used, sustainable energy sources provide the heat.AIT researchers show how the foundry can function and how industrial processes can become climate-friendly.Hardly anyone thinks about it: Frames for mobile phones, metal housings, car parts - these and other objects that many people use every day are industrially manufactured in manufacturing processes that consume a lot of energy and blow large amounts of environmentally harmful CO2 into the air.Sustainability looks different.And that is exactly what Christoph Zauner from AIT (Austrian Institute of Technology) and his team want to change: He wants to make those high-temperature processes in industry, which together with the energy sector are responsible for around 37 percent of CO2 emissions in Austria, more energy-efficient, "green “Use energy sources and pollute the climate with fewer pollutants."The technologies that can do this are available," says Zauner."Due to the price dynamics for natural gas, they are now also economically competitive." Specifically, it is about die-casting processes.Battery trays for electric cars are z.B. produced in this way from aluminum.The starting material is heated to around 660 degrees and melted in an oven.The liquid is formed into the desired shape in the die-casting machine and post-treated to give it the desired properties.Natural gas is primarily used to heat up the melting furnace.The AIT researchers do things differently: in the demo factory in Ranshofen (Upper Austria), they tested a system that uses less energy and uses renewable sources for the energy required.This means that natural gas is completely banned from the process.An innovative cooling system on the die-casting machine ensures energy savings, which not only speeds up the casting process, but also supplies a lot of waste heat at a high temperature level.This is conducted to the melting furnace, where it heats up the aluminum properly."In this way, we need up to a third less energy," explains Zauner.Where the energy that is still needed comes from depends on the individual case.The researchers see several options.One possibility is to initiate the melting process electrically with green electricity."That works with some ovens," says the scientist.An alternative is the use of green hydrogen.However, because some parts of the casting system have to be adapted for this, the heat balance in the furnace changes.Zauner: "The question is whether this changes the mechanical and thermal properties of the aluminum product, i.e. whether the product quality can be guaranteed." The researchers are currently trying to answer this question in the Enviotcast project.Finally, biomethane or synthetic methane can also be used as energy sources.Biomethane can e.g.B. from food waste, synthetic methane with hydrogen, ideally using green electricity."Both are one-to-one alternatives to natural gas, so no changes or process changes are required on the die-casting system," explains Zauner.In the project funded by the Nefi (New Energy for Industry) innovation network, he and his team are examining how the production of methane can best be integrated into the respective industrial site.“Of course, there is an advantage if, thanks to photovoltaics, solar power can be used directly on site to produce methane or if there are wind turbines nearby.But it's also about system design and process optimization.” Simulations help to select the best option from all options in each individual case."Industrial furnaces are the main energy consumers in metal processing," says Zauner."We show sustainable concepts of a 'green foundry' - with solutions that are economically feasible." The use of natural gas is not only questionable for environmental reasons, but also in terms of security of supply.The expert emphasizes that switching the industry from natural gas to sustainable energy sources will make a significant contribution to achieving climate targets.The pollutant emissions caused by the energy and industry sector in Austria in 2020 amounted to 32.4 million tonnes of CO2 equivalent.That's more than the next two largest emitters, transport (20.7 tons) and buildings (8 tons), combined.The melting temperature of aluminum is 660.3 degrees Celsius.It is therefore significantly lower than that of other metals (e.g. iron melts at 1538 degrees. This makes aluminum a good casting material. However, the melting process is very energy-intensive.Subscribe to the "The most important thing of the day" newsletterThe unique journalism of the press.Every day.All over.