Jeremias' Complex Flue System for a Large Bakery in South Tyrol
Just Right for Baking
Flue systems for ovens in large bakeries pose special challenges. At a large bakery in South Tyrol, Chiemgau Kamintechnik GmbH has now completed an exceptionally extensive project. A total of seven ovens are in operation here. The use of exhaust gases and steam, combined with a heat recovery system, contributes to higher efficiency and environmental protection. The appropriate chimney elements from Jeremias are part of the solution.
Chiemgau Kamintechnik GmbH, with 15 employees and nearly 600 projects completed annually, is one of the major chimney construction companies in Germany. Over its 15-year history, the company from Hufschlag near Traunstein has specialized, among other things, in flue systems for ovens. This expertise pays off for bakeries, as even the best oven can only bake high-quality products if the exact right flue system is installed. Furthermore, only a few chimney builders have the necessary experience to install complex flue systems, especially those used in larger bakeries. When the bakery in South Tyrol moved to a new building, the purchase of new ovens was required. The decision was made to choose high-quality products from an internationally operating oven manufacturer, who also took on the planning of the entire system. To provide fresh air and exhaust the air, the oven specialists used nearly 400 meters of stainless steel pipe systems from Jeremias Abgastechnik. The hot exhaust gases and steam from the ovens are now utilized via a heat recovery system to generate thermal energy – thus saving money and contributing to environmental cleanliness.
Four Pipes for a Hallelujah
In the bakery’s kitchen, two deck ovens, used for baking bread, and five stick ovens, used for pastry preparation, are now in place. Each oven has four pipe connections: an exhaust gas pipe, a steam pipe, a fresh air pipe for the burner, and an air extraction pipe that removes hot air when the oven door is opened, using a fan and a hood. The combustion air comes from outside via the rear wall of the kitchen. This ensures low air exchange and high air quality, which is not only more comfortable for the staff, but also prevents premature wear of the modern combustion ovens, which are designed to meet high environmental protection standards. There are even specific regulations that require the combustion air to be drawn from the outside.
Baking ovens are usually heated with oil or gas, and the temperature for baking is around 260°C. Due to heat loss from the burner to the oven, the ovens operate at around 300°C. In the old bakery, the exhaust gases produced during this process were vented via a chimney. Now, the baker uses a heat recovery system. The hot exhaust gases from the burner, called smoke gases, and the steam, i.e., the humid exhaust air from the oven itself, are now routed via a steam collection duct and an exhaust gas collection duct to a heat recovery system. This system allows both types of exhaust air to be utilized in a heat exchanger. Typically, these processes are separated because the smoke gas and steam have different temperatures, and the steam could contaminate the heat exchanger. However, the high moisture content of the steam makes it especially useful for heat recovery.
EW-AL-BI and DW-AL Chimney Systems from Jeremias
For the steam collection duct above the ovens, the chimney builders used the pressure-tight, single-wall stainless steel flue system EW-AL-BI from Jeremias. For thermal reasons, the double-wall system DW-AL was also used for the steam duct in some places. Since steam has a high moisture content due to the baking process, it is crucial that the pipes are absolutely airtight. This is ensured by the push-fit connection with an internal special seal and external clamp. The silicone seal ALBI 26 is heat-resistant up to at least 200°C. Thanks to the push-fit systems, welding on the construction site is not required.
The exhaust gas collection duct is made entirely of the stainless steel chimney from the DW-AL system and is particularly tight with 50mm mineral insulation. As the air flows toward the heat exchanger, almost no heat is lost. After the hot air has transferred its energy to the water in the heat exchanger, the exhaust gas is vented via a main chimney pipe. The main chimney, which is over six meters high, also consists of the double-wall DW-AL pipe.
In a bakery, a lot of hot water is needed, for example, to shower or wash crates. The baker now uses the warm water from the heat exchanger. Theoretically, it would also be possible to generate cold from the warm water using an absorber. The extent of the cost savings is reflected in the projected payback period. With a service life of at least 25 years, the heat recovery system with all associated flue systems is expected to pay for itself in about seven years, depending on oil price fluctuations.
The fresh air and steam ducts are also made from the AL-BI system. The oven outlets are fitted with flue dampers, which prevent exhaust air from flowing back. Pressure in the pipes is continuously monitored via measurement openings. Condensate drains prevent liquid from dripping back into the ovens.
It Works
Bakeries often require many custom-made parts for their flue systems, such as T-pieces with two 45-degree branches. These parts are hand-made by Jeremias in a very short time. "A construction plan is all well and good, but in reality, something is always different. Custom parts often have to be produced quickly. At Jeremias, this is usually done overnight. This saves costs for everyone," says Franz Brüderl, Managing Director of Chiemgau Kamintechnik GmbH. He is also particularly impressed by the high level of technical expertise: "The technicians at Jeremias are so familiar with our plans that we can easily discuss which part is needed over the phone. That's not common and is a real unique selling point." Over 30 custom parts were installed in the large bakery. This is also one of the reasons why all parties involved have profound know-how. The more complex the flue system, the more foresight is required during installation.
"Another plus of Jeremias pipes is the stainless steel finish. Especially in food processing operations, making a good impression is important. With Jeremias' piping, that is definitely ensured," adds Franz Brüderl.
Conclusion
A holistic oven concept and a specifically tailored flue system from Jeremias ensure clean combustion air in the oven burners, the removal of smoke, steam, and fumes, as well as substantial cost savings in terms of energy. The hot exhaust gases are further utilized through a heat recovery system. Well-insulated and tight pipe systems from Jeremias minimize energy loss on the way to the heat exchanger, contributing to the system's efficiency. Furthermore, the proper piping directly impacts the quality of the baked goods. Thanks to years of experience with bakeries, Chiemgau Kamintechnik and Jeremias Abgassysteme, in collaboration with a well-known oven manufacturer, were able to realize a coherent solution.