Making oven technology a hot topic of discussion

Although direct gas furnaces (DGF) remain popular, they tend to require more maintenance due to the large number of burners. This is why many oven experts, even DGF oven manufacturers, suggest turning to forced air or convection heat ovens to save cold hard cash.

“Forced air ovens are far more efficient in today’s environment than direct gas ovens,” said Jerry Barnes, vice president of Babbco. “Forced air ovens can change temperature very quickly because you’re using focused convection heating with powerful, high-range burners. You don’t rely on a hot box.

Additionally, these older radiant heating systems require much longer to heat up and cool down. Specifically, he noted, DGF ovens require 1-2 hours to preheat while hot air ones heat up in as little as 30 minutes.

“As you change products and change the cooking profile of the oven, you reduce latency with convection heating because it can change the air temperature more quickly,” Barnes said. “When you have a production gap, the typical oven overheats and results in burnt edges on one part of the production cycle and light products on the other. Newer ovens, especially air contact ones, do not suffer none of that instant heat effect.

Ken Johnson, president of Gemini Bakery Equipment/KB Systems, also recommended considering an indirect gas oven because it uses about 30% less energy than a DGF oven. Energy is transmitted to products more efficiently with convection than with radiant heat alone.

“Cooking temperatures in convective zones are cooler due to this more efficient heat transfer,” he added. “Gemini/W&P swirl zones allow for lower cooking temperatures, less energy consumption and more even cooking.”

He said the zones feature evenly spaced carbon steel tubes that form the upper and lower furnace heating plenums. A mesh belt support grid is located above the lower pipe plenum. The heating gases then flow through the tubular plenums and radiate energy into the cooking chamber. Recirculated air from the cooking chamber passes through the space between these plenum pipes. Additionally, this variable speed airflow is reversible and can be up-down or bottom-up for different products.

Since introducing convection ovens more than a decade ago, Auto-Bake has converted many of its older thermal oil ovens to convection, noted Scott McCally, president of Auto-Bake Serpentine and Hinds-Bock, both members of Middleby Bakery Group.

“Generally cake producers have been opposed to the use of convection heating because it causes cracking of the product and creates problems with the crust,” McCally said. “Because of the way we can control the top and bottom convection, we can virtually eliminate all of the airflow over the top of the product, which causes these issues, and produce a much better product than an oven type radiant. They can cook the product faster, and instead of raising the temperature to conduct the heat into the product, we can lower the temperature and speed up the fan and use the fan as a mechanical force to conduct the heat into the pans.

Marie Laisne, product marketing manager at Mecatherm, said the company’s M-TA can offer multiple modes of heat transfer, such as convection, radiant heat, or a combination of the two in each independent heating zone.

“By providing just the right amount of energy required in the minimum cooking time to achieve the required product quality criteria, this oven offers an optimal energy consumption solution,” she said.

Mr. Johnson pointed out that Gemini/W&P provides a furnace with radiant heat only, some zones with a combination of radiant/turbulence/convection heating, or all zones with a combination of radiant/turbulence/convection heating. Swirl zones come with two or four blowers for improved convection.

Mr Barnes said hybrid ovens have been around for decades and likened their versatility to a Swiss army knife.

“Hybrid ovens give you multiple tools in your pocket to deploy depending on the product, which helps make the oven scalable,” he observed. “In today’s market, producers have to adapt very quickly to consumer tastes.

Joe Zaleski, president of Reading Bakery Systems, said DGF ovens bake primarily with low-radiation, convection air currents. The product develops and cooks in a calm and humid environment. Mix and match technology allows bakeries to tailor the baking profile to enhance specific product attributes.

“Many hybrid ovens use this very gentle heat to create the texture and flavor profiles of their products in the front areas of the oven and transition to a much more aggressive and higher airflow environment in the later areas of the oven. to dry the product to the final moisture content,” Zaleski explained. “Convection energy is most effective in this drying zone because the heated air impinges directly on the product, reducing the humidity with both heat and air.”

New technologies are also emerging. A few years ago, AMF Den Boer launched the world’s first emission-free hydrogen tunnel kiln. The Multibake VITA tunnel oven offers industrial bakers an efficient solution to reduce carbon dioxide emissions by 99.9% during the baking process.

The modular oven uses green hydrogen, also known as clean hydrogen, a carbon dioxide neutral fuel. Although commercial ovens typically use natural gas as a heating resource, the company said, this new patent-pending technology will virtually eliminate carbon dioxide emissions from the oven while reducing utility costs.

For specialty bakeries that prefer rack ovens, Koenig Bakery Systems offers the Roto Passat SE with 20% energy savings potential.

Christian Benedikt, group leader, oven design, for Koenig, said the ovens use a flow-optimized heating coil, high-quality sandwich insulation with an aluminum interlayer and an adjustable steam and control system. continuously to minimize power consumption. In addition, the oven has a double-walled duplex steel cooking door with rear ventilation for low surface temperatures.

He added that improving energy efficiency can pay off over a year. A bakery operating six days a week, for example, can thus save around 4,000 liters of heating oil, which corresponds to around 12 tonnes of carbon dioxide per year.

With energy prices showing no signs of falling, bakeries need to focus on maintaining ovens and exploring new technologies to consume less and earn more.

This article is an excerpt from the July 2022 issue of Baking & Snack. To read the full article on ovens, click here.

Jessica C. Bell