Müller Technik: No More Negotiations with Gas Suppliers; Müller Technik Heats Offices and High-Bay Warehouse with Waste Heat
In its extensive new facilities, the injection molding company Müller-Technik now only uses gas to heat water for a hand-washing sink. The energy needed to heat the entire facility—including the state-of-the-art high-bay warehouse—is cost-effectively derived from the waste heat of the injection molding plant.
Managing Director Helmut Kohake estimates the savings in heating energy that Müller-Technik achieves thanks to sophisticated heat recovery at 75,000 to 80,000 euros annually. The opportunity to completely restructure the company’s energy management—including the sensible use of waste heat from the injection molding shop—arose with the planning of a new high-bay warehouse with approximately 15,000 pallet spaces and a two-story administrative building.
Müller-Technik specializes in the development and production of innovative components and assemblies, primarily for the automotive industry. Helmut Kohake, Technical Director:
“We are successful because we evaluate new technical possibilities early on and proactively turn them into product ideas. Two- and three-component parts with complex geometries—some of which are further processed in automated assembly lines—the use of gas-assisted injection molding for parts with the highest surface quality, and similarly demanding tasks define our day-to-day business today.”
Accordingly, the company has been growing steadily for years—even during the crisis years of 2009 and 2010. At the Steinfeld site near Osnabrück alone, approximately 70 injection molding machines with clamping forces ranging from 150 to 5,000 kilonewtons, along with the corresponding peripheral equipment, are currently in operation. The next production expansion for larger machines, including a warehouse connection via an automated guided vehicle (AGV) system, as well as a facility for mold maintenance and the production of dust-free products (cleanroom), is already in the planning stages.
The new high-bay warehouse is primarily used for the temporary storage of finished products and granulates that are not stored in silos. This warehouse is connected to the production area via a bridge using an automated transport system controlled by the warehouse management computer. The warehouse, which is approximately 18 meters high in the shelving area, must be heated, as must the picking areas and traffic zones.
To this end, approximately 35,000 meters of plastic piping were installed throughout the new building complex to provide underfloor heating. This resulted in a temperature of 20 degrees in the warehouse area and an average temperature of 21 degrees in the offices, which cover a total area of approximately 1,000 square meters.
“We had already ordered a new cooling system for the injection molding shop, since the old one was operating at the limits of its capacity due to multiple production expansions and further expansion would not have made sense. Oni convinced us that it makes financial sense to use the waste heat from the machines to heat the new complex instead of expensively disposing of it,” explains Helmut Kohake. “After all, we generate so much waste heat that we could heat a small town with it.”
Installation during operation
During several meetings, the project for utilizing the injection molding shop in the high-bay warehouse, the new offices, and the planned maintenance hall for mold making was outlined and refined. Technical and economic considerations, as well as the possibilities for government subsidies, were discussed. In addition, the system was to be modular and expandable to accommodate future growth. Following preparatory work, such as laying pipes, the plan was to install the entire cooling system in production, the warehouse, and the offices within just three months—in the injection molding shop while operations were ongoing. The first step was to connect the hydraulic circuits of 65 injection molding machines with clamping forces ranging from 200 to 5,000 kilonewtons across three halls. “And it worked,” confirms Helmut Kohake, “with only minimal downtime for each machine.”
Most of the equipment, including the control system, is installed on a platform in the warehouse’s picking area to save space. From there, the cooling water flows to the machines via a distribution network at a supply temperature of approximately 30 degrees. The heated cooling water returns at an average temperature of 35 degrees. The control system supplies the warehouse’s heating circuits and the offices with a flow temperature of 35 degrees. Depending on conditions such as the heat generated by the machines, heat demand in the various warehouse and office zones, outdoor temperatures, and other parameters, the control system determines the most energy-efficient strategy, whereby the flow temperatures must ensure both production reliability and the minimum temperature on the surfaces to be heated. This is ensured by the combined operation of various systems.
At the heart of the system is a two-circuit cooling system. Machine cooling, with a supply water temperature of 30 degrees, is provided by idle, glycol-free open-air coolers. Müller-Technik utilizes the waste heat from the return water for heating via underfloor systems and low-temperature air heaters.
Tool cooling, with a flow temperature of 15 degrees, runs in the summer via a highly efficient, water-cooled chiller. The chiller’s recooling is handled by separate, idle, glycol-free free coolers. During the transitional and winter seasons, the Oni management system ensures the optimal integration of the existing free coolers as a particularly energy-efficient “winter relief” for the chiller. As soon as the outside temperature is a few degrees Celsius below the cold water return temperature, the winter relief system begins operation. As early as an outside temperature of about 10 degrees, the chiller is shut down and the free coolers take over the production of cooling water for the tool circuit entirely. With this technology, all new buildings are completely energy self-sufficient in terms of heat supply. “I have absolutely no desire to keep arguing with gas suppliers about prices; our strategy is clearly moving toward 100 percent self-sufficiency in heat.”
A Look Behind the Scenes
Müller-Technik has invested approximately 500,000 euros in energy-saving technology. This made it possible to avoid replacing “traditional” cooling systems and the heating for the warehouse and new offices. Based on Oni’s plans and experience from the first year of operation, Helmut Kohake estimates the savings in operating costs at around 75,000 to 80,000 euros annually. He notes that some fine-tuning is still possible based on ongoing operations.
The European Union contributed to the investment costs: A “substantial” grant was awarded from funding for exemplary technologies, further improving the cost balance. Since Oni is highly experienced in handling such grant applications, appropriate support was and remains available here. Overall, the investment at Müller-Technik is expected to pay for itself through energy savings within five years at the latest. An additional benefit of the energy savings—unexpected in this form but highly attractive—has emerged in terms of product quality. Helmut Kohake: “With the precisely controlled cooling system and its ample reserves, we are observing significantly more consistent cycles under all conditions and, in some cases, better product quality than before. Even at high ambient temperatures, when individual machines previously had to be shut down, we now run consistent cycles, even for complex technical parts.”
This is particularly true in conjunction with the Contura tooling systems, which, with their contour-following temperature control zones, have ensured a significant improvement in quality and shorter cycles. In addition, commissioning additional machines is significantly easier because the overall system offers some reserves and is also expandable.
The sustained growth driven by orders from the automotive industry is also leading to further capacity expansion at the sites in Poland and the Czech Republic. Many orders are now distributed among the three locations to significantly reduce lead times. In addition, there are areas of specialization: While highly automated production of particularly complex components in medium quantities tends to take place in Germany, the international locations primarily supply high-volume components to regional customers in the automotive industry.
Based on our experience with Oni technology, we plan to install it at both plants as part of future expansions.
“Thanks to the right strategies and technologies, I expect healthy growth in the coming years as well. This is supported not only by current orders from automakers and major Tier 1 suppliers.”
About the Company
Müller-Technik was founded 30 years ago. After starting out with two injection molding machines and a small toolmaking shop in Steinfeld, the facility was regularly expanded. Today, it offers 12,900 square meters of production, warehouse, and office space. The majority of its €75 million in revenue is generated by the automotive industry. The German-Polish company Müller-Technik Koszalin has been in operation since 1994. In 2004, Müller-Technik CZ s.r.o. was initially founded as a trading company. This was followed in 2006 by the acquisition of a Czech company in Tuchlovice, which became a wholly owned subsidiary of Müller-Technik. For its successful business strategy, Müller-Technik received the Axia Award in early 2012 and was a finalist for the Oskar Patzelt Foundation’s Large SME Award in 2013.
