McDonald’s halves energy use for kitchen ventilation
Fan-energy consumption in 50 McDonald’s restaurants has been halved by installing fans with ABB Inverter drives.
The electrical consumption of kitchen extractor fans has been halved at 50 McDonald’s restaurants across the country with the help of ABB inverter drives. Dave Holden, project manager for restaurants services with McDonald’s, explains, ‘We were updating old equipment and realised we could reduce our carbon footprint by making large fans run more slowly. ‘Variable-speed control was implemented on fan units with large 5.5 kW motors. These now draw about 2 kW for most of the time, but have the capacity to boost extract volumes significantly at busy times. ‘Variable-speed control gives us the extraction volumes we need while cutting energy use. We will also change our specifications to request variable-speed control when new equipment is purchased.’ The work was carried out by Inverter Drive Systems of Nottingham, an ABB Drives alliance member, which has worked with McDonald’s for six years. McDonald’s objectives were to achieve 40% energy savings and to reduce wear and tear on the fans, including soft start. The IDS solution was 5.5 kW ABB HVAC drives. Blaise Ford of IDS explains, ‘Using the drives’ real-time clocks, we made the fans run at full speed over the busy periods and at 80% speed at other times. This resulted in a 50% saving in energy. On some installations, a boost button allows the fan to be speeded up to its full extraction speed if needed.’ Variable-speed control also cured a problem that affected the operation of cooling equipment in the kitchen. To contain cooking smells within the kitchen area, McDonald’s aims to supply 85% of the air it extracts through air-conditioning plant. High extraction rates were creating an imbalance that caused a rush of cold air into the kitchen whenever an external door or window was opened, affecting the energy consumption of the equipment as it attempted to maintain its cooking temperature. The air conditioning was also made to work harder to maintain a comfortable temperature. Reducing fan speed has alleviated these problems. The average 50% saving in electrical consumption was even greater at sites with oversized fan motors from the 1980s.
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