Bruder Spielwaren GmbH & Co. KG: Achieving Energy Savings Through Play
ONI Wärmetrafo GmbH of Lindlar has contributed its extensive experience and a new cooling system concept. What makes children’s eyes light up and gets grown men excitedly discussing? The answer becomes clear once you’ve seen Bruder’s high-quality plastic toys in person. With sophisticated, educationally valuable, and high-quality play equipment, Bruder Spielwaren GmbH & Co KG from Fürth has achieved success in more than 70 countries around the world. “We develop and manufacture products tailored to children’s unique needs for experience and learning. With our play equipment and toys, children can, on the one hand, be children, live out their dreams, and experience the joy of play. On the other hand, they playfully gather impressions from the adult world that stick with them as a solid foundation for growing up later,” says Managing Partner Heinz Bruder, describing the company’s product philosophy.
Key factors for Bruder’s long-term business success include a keen sense of market trends, innovative strength, customer-focused operations, sound financial management, and leadership with entrepreneurial vision. One key factor in this is the consistent implementation of an energy-saving policy that effectively addresses rising energy costs. Recently, the refrigeration system technology for the company’s significantly expanded plastics processing operations was upgraded by the energy-saving specialist ONI from Lindlar. The advantages of the new refrigeration system concept are its high energy efficiency and operational reliability.
A forward-looking strategy for success
Starting from very humble beginnings in 1926, Bruder Spielwaren is now one of the world’s leading companies when it comes to high-quality, educationally valuable toys. For decades, the company has successfully developed toys that are fun for children, provide long-lasting enjoyment, are safe to use, and at the same time promote children’s cognitive development.
This has resulted in the company’s success story, which is now continuing into the third generation of the Bruder family. The products are known around the globe and are currently shipped to 70 countries worldwide. But Bruder also holds a leading position among major plastics processors in terms of optimized energy efficiency. For years, the company has pursued an aggressive energy-saving policy.
This forward-looking approach addresses the rising energy prices that are expected to continue, with the aim of improving the company’s competitiveness and thereby further expanding its market position. At the same time, however, the company also seeks to demonstrate that the responsible use of primary energy is not only worthwhile from an economic standpoint but also makes a significant contribution to active environmental protection.
At Bruder in Fürth, production is divided into two areas and is supplied with cooling water via two separate networks. A classic dual-circuit cooling system is used to supply the injection molding machines. For mold cooling, a cooling water temperature of 12 °C is maintained year-round, and for hydraulic oil cooling, a cooling water supply temperature of 35 °C is sufficient in the newly constructed cooling circuit, due to the selected heat exchanger geometry. The system design as a dual-circuit cooling system and the selected temperatures in the new circuits ensure that highly efficient energy-saving measures can be implemented in both areas of cooling energy generation. A key approach is found in the cooling water supply for mold cooling.
Typically, the cooling water used for mold cooling and building services is generated by chillers. To make this energy-intensive method of cooling water production as economical as possible, the decision was made to use particularly energy-efficient chillers. However, since the goal was to tap into further energy-saving potential even after optimizing chiller operation for energy efficiency, an energy-saving circuit was designed for the transitional and winter months to reduce the load on the chillers. Another area ideally suited for the successful implementation of energy-saving measures is machine cooling. Here, the energy used during the transitional and winter months can be utilized multiple times through the use of heat recovery.
Refrigeration unit in minimal operation
Injection molds require cooling water with a supply temperature of approximately 12 °C year-round, with the highest possible reliability of supply. In many cases today, electrically powered chillers are still used throughout the year to produce the cooling water, which leads to significant cost burdens due to high electricity consumption. Furthermore, the operating costs for a cooling system exceed the system’s acquisition costs many times over during its service life.
Even if one considers only a moderate price increase for primary energy sources, the share of energy costs in the total costs becomes a significant and serious factor. To effectively address this issue, the project managers at Bruder specified from the outset the requirement for particularly energy-efficient cooling water generation. For this reason, the decision was made to implement a system solution that is inherently energy-efficient and also largely eliminates the energy-intensive use of chiller technology throughout the year.
To produce the cooling water for the molds of the injection molding machines in Fürth, particularly energy-efficient chillers were therefore selected. This design of the machines achieves high efficiency, ensuring very low energy consumption even during continuous full-load operation. Although the operation of the chillers had already been optimized from an energy perspective through this design variant, the goal was to reduce the remaining energy consumption to an economically viable level through additional measures.
The goal was to ensure that the system technology used would limit chiller operation as much as possible to the summer months and a short period during the transitional season. To this end, the chiller system for the tool circuit was equipped with a so-called ONI winter bypass. During the transitional and winter periods, this system technology takes over the cooling water supply to the mold cooling circuit in place of the chillers.
This technology uses the freely available ambient air as a cooling medium. As soon as the outdoor air can maintain the required cooling water temperature, the chillers are simply shut down and no longer consume any electricity. The electrical energy consumption for winter load reduction is reduced to approximately 2–3% of a chiller’s capacity. As a result, chillers are not used for approximately 65% of the operating time.
This saves a great deal of energy and money. The associated energy management is handled by a dynamic control system developed by ONI, featuring energy-optimizing system software. This ensures that cooling is operated with the lowest possible energy consumption at all times. Furthermore, it ensures that the winter load reduction remains active for as long as possible, because every hour the chiller remains shut down is worth real money to the operator.
Heating with cooling water
Plastics processing is inherently extremely energy-intensive. In this regard, it is understandable and reasonable for plastics processors to want to reduce their energy costs as much as possible. Ideally, this is achieved whenever it is possible to reuse essential energy multiple times. The cooling energy supply for the injection molding machines at Bruder Spielwaren in Fürth exemplifies this optimal approach.
Thanks to the heat exchanger geometry of the oil coolers in the injection molding machines, a cooling water temperature spread of 35/40 °C was selected for the newly constructed cooling circuit. This increased system temperature pair, compared to a standard spread of 30/35 °C, delivers several advantages. First, the machines’ cooling water supply will be able to manage without peak cooling via secondary systems, even during the highest summer temperatures. Furthermore, the cooling water return at a temperature of 40 °C provides waste heat from the machines, which can be directly utilized for heating purposes via a heat recovery system. In this specific case, the waste heat, with an output of approximately 500 kW, is utilized for multiple applications simultaneously. As a result, waste heat that previously had to be cooled back down at great expense is transformed into valuable heating energy that replaces natural gas or heating oil. Consequently, heating costs can be significantly reduced. This low-temperature technology also offers a particular advantage regarding heat distribution within the space. Heat emitted by conventional heating systems naturally travels along the shortest path to the ceiling of the room or hall, where it is typically not desired. Low-temperature heating mixes much more quickly with cooler room air, so that the heat ultimately reaches where it is truly needed.
Energy-efficient cooling water supply
In almost no other area does the implementation of an energy-saving measure have such a significant impact as in the cooling water supply. Choosing the right system technology and temperature spread ensures low costs in primary cooling water generation right from the start. The use of heat recovery drastically reduces heating costs because free waste heat replaces expensive primary energy sources such as heating oil or natural gas.
At the same time, heat recovery ensures that separate recooling of the cooling water is not required during the period when waste heat is being utilized. Naturally, this also eliminates the costs associated with recooling. By using highly energy-efficient chillers and an integrated winter load relief system, electricity consumption for the cold water supply to the mold cooling system is reduced to a minimum. Overall, the consistent implementation of the requirements defined by Bruder not only reduces the share of energy costs to a minimum. With this energy concept, planned and implemented by ONI experts, Bruder is also setting an example in terms of active environmental protection. Both economic and ecological benefits are thus derived from the use of energy-saving measures, particularly in the plastics processing industry.
