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Miralis – Simultaneously increasing production and decreasing energy consumption

“Our dust collection system was the obvious target for an energy reduction project because it’s our biggest energy consumer,” says Donald Brisson, the company’s director of operations in Rimouski, about 300 kilometres east of Quebec City on the St. Lawrence river’s south shore. A new on-demand control, installed in fall 2008, has saved the company about $50,000 in annual electricity costs related to dust collection. The new system had a capital cost of $200,000.

“Before the upgrades, the dust collection system used 23% of the energy we use in production. Afterwards, it dropped to 12%, despite the fact that our production capacity has increased by about 20%,” Brisson says.

Miralis, a CIPEC Leader in the general manufacturing sector, employs 220 full-time staff working at about 125 workstations with various equipment in an 11,600 m2 facility.

The dust collection system uses large air conveyors that suck wood dust away from workstations. Most of Miralis’ workstations do not operate continuously, but conventional dust collection systems operate all the time to stop dust from accumulating. Drills and band saws, for instance, are generally used only about 25% of the time during the day, while panel saws and wide belt sanders are used up to 80% of the time.

To address these variable ventilation requirements and the related energy demand, Miralis hired SyEnergy Integrated Energy Solutions to study the system and implement a solution. Ecogate technology offered the best solution, because it addresses ventilation needs for individual equipment, while maintaining the required airflow in the ventilation ducts.

The consultants isolated each individual workstation and then considered the workstation network as a whole. The Ecogate automation program was adapted to the workstations’ operating schedules. Ecogate’s central control can reduce ventilation for equipment that operates only 20-30% of the day, while increasing ventilation speed to sweep the entire collection system regularly. With Ecogate technology, Miralis saved 650,000 kWh/year of the 1.32 million kWh consumed by the dust collector motors.

The fan’s motor power consumption is significantly reduced and motors run quieter, cooler and with less mechanical stress. Noise at the fan and inside the factory is significantly reduced. “Employees appreciate the upgrade because the air is cleaner and the facility is quieter,” Brisson says.

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The computerized Ecogate System is completely automated thanks to sensors and controllers. When a machine is turned on, the sensor signals the controller to open the right gate and turn on the dust collector. When the machine stops, the gate closes and the dust collector stops. By closing unused outlets, there is higher air-velocity at the machines’ outlets, resulting in better sawdust extraction and cleaner air.

The Ecogate System monitors all of the machines in the Miralis plant and, through a variable speed drive, continually optimizes the amount of power supplied to dust collection. The system is also designed to maintain minimum airflow in the duct system by opening additional gates when necessary to avoid sawdust settling in the duct system.

The technology is relatively new to Canada, with only Miralis and a Manitoba-based company now using it. However, the technology has the potential to reap energy savings in the wood and printing industries, and also in welding operations. Miralis also invested $45,000 in a complete refit of the lighting system. These lighting upgrades cut electricity consumption related to lighting by about 45%.

Brisson plans to build on the success of the lighting and ventilation projects by improving energy efficiency in the paint shop. “In the winter, we have to heat air that is brought in to replace the vented air. We are looking at things like variable drives to reduce air exhaust, heat exchangers and even a solar wall.”