The Burger Group invests in a central technotrans cooling solution using a natural refrigerant
Moving away from fossil fuels: this is one of the central sustainability goals of the Burger Group from Schonach in the Black Forest. The longstanding specialist in drive solutions is consistently relying on environmentally friendly technologies. A key component in this transformation is the new cooling system from technotrans for the manufacturer’s injection moulding production. It replaces the existing system and is a forward-looking investment, not least because of its use of the natural refrigerant R290 (propane).
When it comes to drive technology, the Burger Group is one of the world’s leading solution providers. The group operates in various sectors such as mobility, building technology, industrial technology, medical technology, the watchmaking industry, and the manufacture of power tools. It comprises 11 companies across 8 locations in Europe and North America, employing over 1,200 people and generating annual revenues of around €200 million. A distinctive feature of this drive technology specialist is its high in-house production share. While electric motors and ball bearings are typically purchased components, the Burger Group manufactures its other components in-house. This includes producing plastic parts through KBS-Spritztechnik GmbH in Schonach. Approximately 95% of the products manufactured here are used within the group, with only 5% being sold on the open market.
"We process engineering plastics, primarily polyamide, POM, and PBT, sometimes using two-component injection moulding and in combination with LSR," explains Matthias Fehrenbach, General Manager of KBS-Spritztechnik GmbH. Hybrid components, where machined or stamped parts produced within the group are overmoulded, are another focus area. More than half of the 50 injection moulding machines (250 to 3,500 kN) are hybrid, toggle-less injection moulding machines with hydraulic clamping and electric injection units. High precision is required for gears, screws, spindles, racks, housings, or belt pulleys produced in Schonach. Proper thermal management is essential. "The core of our previous cooling system dated back to our beginnings when we moved injection moulding production from our headquarters to the Fabrikberg in Schonach in 1999. With every new construction phase, the system was expanded and adapted. However, due to increasing failures, we decided to invest in a completely new cooling technology supply," Fehrenbach reports.
Focus on Future-proofing and Efficiency in Planning
In 2023, the concept took shape. Among numerous providers, technotrans quickly emerged as the preferred partner for the cooling technology. "Our managing director, Thomas Burger, is deeply involved in exploring alternative energy applications and contributed his ideas from the outset," says Fehrenbach. "We wanted a system that is technologically state-of-the-art and ideally capable of serving us well for the next 20 to 25 years." The original idea to house all components of the cooling system in a shipping container and install it on the roof was abandoned after Thomas Burger proposed an alternative: embedding the cold-water tank underground to leverage the stable temperatures there to support cooling and save on cooling capacity.
The Burger Group handled the underground tank installation themselves. The eight-cubic-metre tank sits on a concrete foundation underground. "We added an extra shaft to pump out any accumulated water to prevent the tank from floating. The stainless steel pipes embedded in the ground required special wrapping for corrosion protection," explains Fehrenbach. Although this involved additional effort, it proved worthwhile. The underground tank does not take up valuable production space and, due to its size – holding 6,000 litres of water – it supports temperature management. technotrans’ ability to accommodate such customer-specific requirements stems from shared expertise in engineering and high production depth. technotrans handled the precise calculation, planning, execution, and turnkey installation of the system. Tobias Escher, Sales Manager Cooling Solutions at technotrans, recalls: "The Burger Group already had experience using underground tanks and managed the installation themselves. We advised on the tank size and connected the cooling system at a clearly defined interface."
A Single Cooling Circuit Replaces a Dual-Circuit System
For the new cooling concept, technotrans adjusted the temperature control system. Previously, KBS-Spritztechnik operated with two cooling water circuits with supply temperatures of 16°C and 25°C. "The Burger Group primarily produces technical components that are generally processed at higher temperatures. As a result, we could increase the temperature on the tool side. This allows the customer to operate with a single-circuit system designed for a consistent supply temperature of 25°C," explains Tobias Escher.
The benefit: the higher the supply temperatures, the lower the operating costs, and the longer the service life of the free cooler, which technotrans equipped with a cooling capacity of 300 kW. "The difference between the previous and current temperature levels results in slightly longer cooling times for the tools. However, we have not experienced any issues with any of our technical components so far," emphasises Matthias Fehrenbach.
Another change involves the medium used: the previous central cooling system at KBS-Spritztechnik employed a water-glycol mixture, whereas the new system uses pure water. This offers better heat transfer and complies with water resources regulations, as no hazardous substances are used. The system serves 50 injection moulding machines (tool and hydraulic cooling) and their temperature control units, as well as a computed tomography scanner, which is supplied with water cooled to 18–20°C by an additional cold-water unit. At supply temperatures of 25°C and return temperatures of 30°C, the passive free cooling capacity meets the needs of KBS-Spritztechnik for most of the year. For this purpose, technotrans installed a hermeticool cooling system on the roof of the building. When outdoor temperatures exceed 25°C in summer, a downstream active compact refrigeration unit takes over the cooling. The technotrans energy-saving module, combined with an electronic expansion valve, enables a floating condensation temperature regulation. This reduces running costs by approximately 25% compared to conventional chillers.
Future-Oriented: Moving Away from Fossil Fuels
The energy from the return flow contributes to heating the building, which also houses the sister company SBS-Feintechnik. A heat pump built and installed by technotrans raises the temperature level to approximately 60°C, supporting the central heating system, which currently still includes an existing gas heating system. This setup provides heating for an associated apartment and the factory, which is divided into three sections.
"Before we remove the gas heating entirely and rely solely on energy from the heat pump, we wanted to observe one heating period after installing the new system," says Fehrenbach. "If the performance of the single heat pump is insufficient for the Black Forest winters, we will consider geothermal energy or an additional heat pump. In any case, our goal is to move away from fossil fuels." An electric heater provides backup in case of heat pump failure. Another option, not yet utilised, is to directly use the 30°C warm water from the injection moulding return flow for underfloor heating.
Sustainable and Legally Compliant with Natural Refrigerant
Both the heat pump and the compact refrigeration unit use the natural refrigerant R290 (propane). These energy converters operate with a naturally occurring gas with a Global Warming Potential (GWP) of just 3. By comparison, the GWP of the climate-friendly refrigerant R513A is 631. Additionally, R513A is a partially fluorinated refrigerant subject to the F-gas Regulation. "Whether it’s the PFAS discussion or the F-gas Regulation, propane ensures compliance for the coming years. Our investment is future-proof," confirms Fehrenbach.
Cooling systems using the natural refrigerant R290 (propane) are increasingly attracting interest and are popular attractions at trade fairs. This includes the heat pump and the compact refrigeration unit for the Burger Group, which technotrans showcased at the autumn Fakuma trade fair in Friedrichshafen before setting it up in Schonach at the end of 2023. "The subsequent installation was absolutely seamless," notes Fehrenbach. technotrans provided two rental cooling units for several months during the dismantling and replacement of the old system, ensuring uninterrupted production at KBS-Spritztechnik. "Up to four technicians worked on-site during the installation of the new system, collaborating seamlessly. It all went off without a hitch, which is not always a given," says Fehrenbach.
Efficient Installation Despite Adverse Conditions
The only challenge was the weather: "Last winter, there was hardly any snow. But during the installation, we faced chaos, with snowdrifts on the roof where the two external units needed to be installed. Nonetheless, everything went smoothly," says Fehrenbach. Inside, technotrans utilised the space previously occupied by the old system for the installation of the pump and control technology. By relocating the tanks outdoors, the available area was sufficient. Due to the low refrigerant charge, the 44-kW heat pump could also be installed indoors. As the injection moulding production operates in three shifts and is adjacent to a residential area, technotrans equipped the compressors of the rooftop cooling unit with soundproof hoods and designed the refrigeration unit for quieter operation.
"Consultation, installation, and commissioning were all top-notch. The overall package from technotrans is perfect," concludes Fehrenbach. "The system has been running without any issues since Christmas 2023. As expected, everything works excellently."
For more information, visit:
www.technotrans.de
www.burger-group.com