Energy cost reduction at a Bakery factory

Operational has designed and installed a Heat Recovery System in one of Spain’s leading bakery manufacturers.

The company specialises in the production, sales and distribution of breadcrumbs to major food chain stores all over Spain.

In one of their factories in the North of Spain, they have two bakery lines. Each line has an oven with three separate chambers, both being served by one associated drier that operates with hot air.

Operational recognised the potential to significantly reduce the gas being consumed in the driers by reutilising the heat from the existing ovens for each production line.

With this objective in mind, Operational engineers designed and installed a Heat Recovery System that linked the exhaust stacks of the ovens with the fresh air inlet of the driers. The ductwork was constructed in thermally insulated stainless steel and the distribution of hot air to the driers is controlled by a modulating damper system.

The whole system logic is currently controlled by a PLC where key process data can be introduced. The static pressure in the oven stack and the temperature in the duct are the drivers that regulate the system.

The results:
• 3.000 Nm3/h exhaust air per oven, at 200°C minimum, is recycled to each drier
• A saving in excess of 100 kWh thermal energy is made in each drier
• 3 0% overall reduction in gas consumption
• Savings of 1,200 MWh of gas per year, representing a reduction of 250 tons per year in C02 emissions to the atmosphere

The Technical Manager of our client at the bakery site was delighted with the results achieved and stated “this system is really saving money without in any way adversely affecting our process.”