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Nov 1, 2014 - Building

Producing Energy-Efficient Bakery Ovens Efficiently

To achieve an ambitious goal of trimming energy usage by 5 % annually, baking technology specialist MIWE relies on the WAGO-I/O-SYSTEM.

Getting up at the crack of dawn, preparing the dough and firing up the oven: the baking profession, in its original form, is an honorable job — and an energy intensive one. Creating baking ovens for bakeries that are as energy efficient as possible is one of the goals of MIWE Michael Wenz GmbH. Additionally, the company strives to manufacture extremely efficient ovens for its own facility. The ambitious goal — 5 % energy savings annually — is supported by monitoring systems that rely on the WAGO-I/O-SYSTEM.

MIWE Michael Wenz GmbH has, during its 100-year history, grown into an international company with more than 700 employees. Technologically, the firm has spent the last several decades on the cutting edge of the baking industry. And the company has set lofty goals for developing energy-efficient technology. Thus, new MIWE products receive an e+ seal of quality if they are at least 10 % more energy efficient than the preceding model. And MIWE’s quest for efficiency doesn’t stop there, the firm’s energy division takes the additional step of assisting customers in optimizing the energy efficiency of entire bakeries.

Energy Efficiency in its own Production Facility

In order to lead by example, MIWE not only develops energy efficient products, but it also invests heavily in the energy efficiency of its own production facility. The goal is tremendously ambitious: reduce annual energy consumption by 5 % over the previous year. And, with total annual energy costs of more than one million euros, this is also a potentially rewarding project. The extensive production space at the Arnstein, Germany location encompasses approximately 100,000 m2 of total area; oil and gas are the facility's primary heating sources. The sprawling nature of the facility itself makes monitoring individual systems quite difficult. Not surprisingly, related expenses are quite high, and in spite of this, disruptions are often not immediately detected.

The project began with a survey of the technical building equipment. “All of the systems designed and installed in the past were isolated solutions,” explains Christian Müller, head of Facility Management at MIWE. As such, energy efficiency was only considered in the most isolated cases. A typical example is the new chiller on the roof of the largest production hall, where laser cutting systems, press brakes and other machines for metal processing generate considerable heat of up to 280 kW. “The designer equipped the four cooling units, which operate using adiabatic cooling, with the basic model of the manufacturer's controller; this made it is impossible to control the damper drivers and exhaust air systems. Therefore, you could not regulate it to run efficiently,” concludes Müller, listing one of the disadvantages of the current installations. Interfaces for higher-level building automation systems were also not provided. In addition, the controller in the original installation depends on just one single temperature sensor — in a production hall that is 100 m in length.

Müller and his team developed a concept that was based on the WAGO-I/O-SYSTEM. Step by step, all building automation systems were connected to programmable controllers that form the brain of an automation node. In each building, the team created an “Information Focus Point” where every signal and error message for all of that building’s automation equipment intersects. A WAGO controller was then installed inside each Information Focus Point to regulate all aggregates and devices, such as the air conditioning. There were many reasons for selecting the WAGO-I/O-SYSTEM explains the facility manager, “Suitable modules for the most varied signals and interfaces are available and this makes us much more flexible. In addition, communication using MODBUS via TCP/IP has great advantages because a powerful network infrastructure was already available within the facility.”

Optimizing Air Conditioning in the Production Hall

Under the new concept, the large production hall is now divided into three distinct climate zones. Sensors in all three zones detect temperature, humidity, air pressure and air quality in their respective zones. The measured values are supplied to the controller by modules from the WAGO-I/O-SYSTEM. The controller can then run the frequencycontrolled fans on the air conditioning units, the ventilation dampers, the exhaust air units and the devices for controlling air humidity as needed. The precise process enables the controller to prevent unnecessary, and wasteful, energy usage. “In the past, there were times when the air-conditioning was running full blast while the hall was being heated with warm air recovered from the compressor systems,” recalls Müller. All of the aggregates are now so tightly controlled that the climate always remains optimal while simultaneously ensuring that the least amount of energy is consumed. Connections to the fire alarm system were likewise implemented, namely via digital input modules from the I/O-System. In case of a fire, all fans must be switched off to prevent the smoke from spreading.

MIWE facility management programmed the controller themselves using CODESYS. The web server, which comes standard on every controller, is also ideal for MIWE. Using the web server, it is easy to keep an eye on the system's current status via the integrated web visualization. The entire architecture is based on decentralized controllers located in the Information Focus Points. “At the moment, we do not have a higher-level SCADA system,” explains Müller. Following the success in the large production hall, the concept will be gradually rolled out into the other buildings on the company grounds. The modular structure of the system was a decisive advantage in this, with Müller adding, “We only have to select the appropriate modules from the WAGO system, add them to the I/O nodes and then we can connect almost all aggregates and systems.” The second company location, in Meiningen, Thuringia, Germany will also be equipped with the same system.

Certification of Energy Management

The entire energy management system at MIWE should receive DIN EN ISO 50001 certification within a year. For this purpose, Müller and his colleague, Andreas Kröber, have completed continuing education courses in energy management. A certified system forms the foundation for sustainably improving the energy efficiency of the MIWE Group while simultaneously holding the line on energy costs. “The WAGO-I/O-SYSTEM can be used universally, making it the ideal foundation,” summarizes Müller.


  • WAGO controllers optimize the climate within expansive production spaces while using the lowest possible amounts of energy.
  • Integrated web visualization permits network access to status values at all times.
  • Connections to the fire alarm systems were also made using digital input modules from the WAGO-I/O-SYSTEM.

Text: Frank Sünkel, WAGO
Photo: MIWE, Norbert Schmelz/vor-ort-foto.de

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