A strong structure
The baking chamber itself — whether a tunnel, multideck or rack configuration — can have an impact on the baking efficiency of the oven. This includes the insulation of the oven’s walls, belt re-entry and even the possibility of a coating to improve radiation baking.
A well-insulated baking chamber ensures that the heat is used for what it was originally intended — baking the dough. “Increased insulation thickness improves heat loss reduction and helps with the general surrounding bakery environment conditions,” said Stephen Renaud, vice-president, sales and project development, ABI Ltd.
Baker Perkins addressed thermal efficiency with non-settling insulation as well as thicker walls. All this was done in an effort to preserve the heat inside the chamber and the carefully cultivated baking environment.
An insulated belt return helps preserve this baking environment. “If the band returns in an unheated space, you lose energy,” explained Damian Morabito, president, Topos Mondial Corp. “Your whole oven hearth got cold coming back and needs to heat back up with the product.” Topos/J4 ovens feature an insulated belt return to ensure the band doesn’t lose precious heat.
This also saves on energy. “By doing this, energy isn’t wasted by having to re-heat the belt every time it enters the oven,” said Nathan Stockton, sales manager, Babbco.
Gemini Bakery Equipment’s indirect-fired tunnel ovens feature a closed-loop design to be energy efficient. The ovens also have an insulated belt return chamber with minimal surface losses and can use up to 50% less energy than direct-fired ovens.
WP Bakery Group also knows the value of a well-insulated and sealed baking chamber. To retain heat and steam as well as maximize energy efficiency in its WP Rototherm Green oven, the company offers the WP Thermogate Package, a new concept featuring full surface insulation, separate insulated floor, automated retractable ramp and the steam-proof door seal secured all around. “The WP Thermogate continuously circulates heat within the closed energy block above the baking chamber, between baking cycles. This allows for quick return to the baking temperature, batch to batch,” Ms. Kennedy said, adding that baking times are reduced by 20% or more and recovery time by up to 40%.
Beyond the design of the physical structure, the material coating the inside of the baking chamber can improve radiant heat transfers. The ceiling and the inside walls of ABI’s baking chambers are lined with refractory material to ensure the best baking results.
Reading Bakery Systems researched a variety of ceiling options to discover a material that could produce the highest radiant heat transfer and still be considered food safe. “By performing this study, it would allow us to apply less energy to heat this material and still achieve the highest desirable radiant heat to transfer to the product,” said Shawn Moye, vice-president of sales, Reading Bakery Systems.
Reading discovered the proprietary material Thermatec which it then applied to the ceilings of its ovens that need a high-radiant heat component.
J4 tunnel ovens, represented in the US by Topos Mondial, feature STIR technology, a nano-emissive coating on the inside of the baking tunnel that improves the radiant heat transfer. “It changes the wavelength of the thermal radiation to a wavelength that penetrates deeper into the dough so you actually get the heat inside the product,” said Ondrej Nikel, PhD, director of engineering, Topos Mondial. “So instead of heating the surface of the product and waiting for the dough to conduct the heat into the center, the waves actually get deeper into the dough and heats up the product quite a bit faster.”
In the next segment, the heat comes on.
