Energy consumption is undisputed at the top of the industry’s concerns and efforts for improvement. Tunnel ovens offer opportunities to go the extra mile on the path to resource savings.
The newest technology developments make tunnel ovens more energy-efficient. As more advanced systems enable energy savings, the equipment itself is easier to use, which contributes to minimizing waste of any kind.
User-friendly efficiency by RBS: the Emithermic XE Oven Zone
Reading Bakery Systems (RBS) recently launched the new Thomas L. Green Emithermic XE Oven, which was designed as an upgraded technology to replace traditional Direct Gas Fired (DGF) ovens for biscuit and cracker baking. The new Oven Zone replicates the baking process of a DGF cracker or biscuit oven zone, but uses less energy, has lower emissions and simplifies cleaning and maintenance operations.
At the same time, it also improves baking performance. Typically, DGF oven zones contain a very large number of direct-fired gas burners above and below the baking band. They supply low- and high-level radiation to heat the product and the traveling baking band in an environment with little to no convection currents.
The Emithermic XE Oven zone is designed to bake via electric radiant heat elements, high radiant Thermatec Panels, and convective heat, eliminating all ribbon burners. The oven delivers a more balanced heat to the product, and imparts the high radiant heat required to develop the flavor and texture of the crackers.
“The Emithermic XE zone matches the same DGF oven heat trace by using a centralized penthouse (gas or electric) to circulate and impinge heated air on thermal plates above the product and on to the baking band below the product. High-intensity electric radiant burners then provide the highlighting blisters and colors on the top of the product,” RBS explains.
A unique feature of the new oven zone is the ability to emulate either the still air environment of a DGF or Cyclothermic oven zone or the convection air zone of a dryer, to optimize the baking process. “The baker can configure and store zone settings of product formulas that require either more humidity for product development or less humidity for product shape setting and drying,” RBS says. This unique atmosphere allows baked goods to develop and expand while retaining the necessary moisture to create the product’s flavor and texture profile.
“Using convection air to heat a small humidity-controlled product zone around the product, the Emithermic XE oven zone imparts high- and low-level radiant heat on the product from above and conductive heat from below. To drive humidity out of this small bake zone, the operator can selectively impinge the product with convective air to remove excess water vapor,” RBS explains. The operator easily controls the air temperature, the low-level radiant temperature, high-level radiant energy and the convection air currents all from a single oven control center.
By comparison, traditional DGF oven ovens are more difficult to maintain and its baking results are not as consistent. DGF ovens need to balance more variables to deliver consistent heat to the product, due to the large number of ribbon burners throughout the oven’s length (all of which need maintenance and adjustments).
The new oven zone also minimizes waste heat: “In most tunnel oven baking processes, only 25-50% of the oven’s heat goes into baking the product. The remaining 50-75% of the heat is considered waste. The computer-controlled Emithermic XE zone minimizes waste heat by providing product downtime software slowing the circulating air and adjusting burners to maintain zone temperatures without product,” RBS specialists explain. Optionally, an exhaust heat exchanger can be incorporated to preheat make-up air entering the oven to replace the high moisture air circulating in the oven to bake the product, saving energy.
The flexibility of the Emithermic XE zone makes it best positioned as the first third of a tunnel oven of three or more zones. “Emithermic XE zones, coupled with convection zones, optimize the baking and drying process by providing a single hybrid baking system delivering efficiency and flexibility for many different types of product profiles,” RBS summarizes.
Adding to its efficiency, the new Emithermic XE zone is easier to operate and maintain; electric burner components are easily replaced, which eliminates downtime that would be required for cleaning, tuning, or replacing gas burners. Since the heating system of an Emithermic XE zone resides in a penthouse above the oven, operators have access to both sides of the oven for cleaning. Large access doors for cleaning and maintenance are spaced every three meters to allow for thorough sanitation between product runs. The oven belt returns within the oven zone to minimize heat losses while providing a flat surface below the return path for sanitation.
“The flexibility of the Emithermic XE zone makes it best positioned as the first third of a tunnel oven of three or more zones. Coupled with convection zones, they become a single hybrid baking system for many different types of product profiles. ”
Reading Bakery Systems specialists
Long-term sustainability is covered
An electrically heated Emithermic XE oven zone emits no greenhouse gases, RBS highlights. Cameron Johnston, Director of Engineering, RBS, explains what makes the Emithermic XE technology viable: “Commercial cracker bakers are under pressure to reduce energy consumption and harmful emissions and increase operational efficiency. To do so, bakers are looking to replace DGF ovens for newer, more user-friendly technology. RBS ovens and dryers will be operating for the next 24-40 years. Therefore, our oven systems must help bakers achieve their sustainability goals, while optimizing the cracker platform for product quality and production throughput.”
RBS thinks of snack baking sustainability in terms of how it affects three pillars – People, Process and Prosperity:
+ People – The Emithermic XE oven zone is as simple to operate as a convection oven zone. As the labor force moves around more freely in the LinkedIn job marketplace, the controls of ovens need to be more intuitive so new operators can understand how to bake their products more consistently, without steep learning curves. The Emithermic Oven has only 6 control points, compared to the DGF oven, which has more than 30.
+ Process – The Convection and Emithermic ovens zones designed by RBS already offer sustainable energy solutions today. In addition, “Our standard Emithermic XE oven zone uses a hybrid of electric radiant energy coupled with gas-heated convection air to bake products,” according to the company. This oven can either be fully electrically heated or it can be delivered as a gas oven that can easily be converted to electric in the future.
+ Prosperity – The Emithermic XE oven zone operates more efficiently reducing energy, waste and labor while simplifying the baking process.
The article is part of an extended feature, published in Baking+Biscuit International, issue 5 – 2023.
