ABB solution makes sugar cane plants energy self-sufficient
In the past three to four years alone, some 20 sugar cane plants throughout Central America - one of the world’s leading sugar producing regions – have selected an ABB solution which enables them to become self-sufficient producers of energy while simultaneously increasing their revenues by as much as $1 million a year.
The solution uses a highly energy-efficient ABB variable speed drive system - consisting of ACS 1000 medium voltage drives and high-efficiency induction motors - to replace inefficient steam turbines to control the consumption of electrical energy at the cane crushing mills.
One plant alone in Honduras has increased its annual revenues by $1 million, as well as enjoying other bottom-line benefits like rapid return on investment, reduced maintenance costs, higher uptime and improved process operation.
Sugar plants generate electricity by burning bagasse – the principal waste product after the juice is extracted from the cane – to produce steam for the turbines that run the cane crushing mill.
These turbines operate at low levels of efficiency and they waste steam that could be used to generate more electricity.
By replacing them with high efficiency ABB drive systems to feed power to the cane crushing mill, the steam is used exclusively to generate electricity – enough to meet the needs of the entire plant and provide a large surplus which is sold to the grid.
Besides boosting revenues and providing a rapid return on investment, the ABB concept improves plant productivity and the cane-crushing process.
The exceptional speed and torque control of ABB drives enables the mill to operate at constant speed and to start at high torque after a production stop.
Maintenance requirements and noise emissions are negligible.
ABB offers a complete single-vendor solution, ranging from medium voltage drives and robust, high-efficiency induction motors to the power equipment for exporting the surplus energy safely and reliably to the local grid - switchgear, transformers, protection and all auxiliaries.
McDonald’s restaurants save 50% on fan power with ABB drive solution
Dave Holden, Project Manager, Restaurant Services, for McDonalds, says: “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 2kW 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.”
Although Holden had no particular product in mind, he did want a branded drive that had been proven reliable: “Reliability coupled with a fit-and-forget setup was essential. Our managers work incredibly hard running successful restaurants and do not want to be troubled with technical equipment unnecessarily.”
ABB Drives Alliance member, Inverter Drive Systems (IDS) in Nottingham has been working with McDonalds for six years and is included in McDonalds’ handbook of recommended suppliers. Holden has a particular set of requirements for his drives supplier: “We want flexibility, a ‘can-do’ attitude and trust. Inverter Drive Systems have proven reliable in all of these areas,” he says.
McDonalds was hoping to see 40% energy savings and less wear and tear on the fan, including soft start-up. IDS were asked to look at the application and come up with the correct drive.
IDS’ solution was 5.5kW ABB HVAC drives. Blaise Ford of IDS says: “Using the drive’s real-time clock, 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. Another major benefit was the reduced fan noise that this drive method allowed, particularly important to McDonalds at night.”
Variable speed control also cured a problem which was affecting the operation of cooking equipment in the kitchen. In order to contain cooking smells within the kitchen area, McDonalds aim to supply 85% of the air it extracts through air conditioning plant. High extraction rates was creating an imbalance that meant whenever an external door or window was opened, there was a rush of cold air into the kitchen, affecting the energy consumption of the equipment as it attempted to maintain its cooking temperature. It also meant the air conditioning was working harder to maintain a comfortable temperature. Reducing the fan speed has alleviated these problems.
Holden says: “The average 50% saving in electrical consumption across the restaurants was even greater in select locations that had oversized fan motors from the 1980's. As well as reduced utilities costs, we now have fewer operational difficulties with the kitchen equipment as a result of being able to balance the extract volume.”
Another advantage for Holden of using the ABB/IDS solution was that the setup required no involvement from the restaurant management team. The retrofit work was fitted in around the busy times in the restaurant to avoid disruption. The fan would normally be fitted on one day and changed over in a quiet time the following day, such as mid-morning, or even on the same day when a standby fan was available. Although most of the work was done by IDS engineers, on some locations work was carried out by other companies in ABB Drives Alliance.
ABB drives cut energy costs by a cool 11 percent
Poole’s Pies of Wigan makes up to 200,000 meat pies per day, as well as 80,000 other puff pastries. Like most food manufacturers, refrigeration and freezing systems can account for as much as 80 percent of the company's energy bill.
So when Poole wanted to cut costs, it focused on potential efficiencies in refrigeration.
The company's new spiral belt freezer increases freezer storage capacity, while the refrigeration system needs less power now thanks to ABB low voltage AC drives controlling two fundamental components, the compressor motor and condenser fan.
Most electric motors operate at full speed unless they are regulated. This is often done by means of a throttle, which is like driving a car with one foot on the accelerator and the other on the brake.
Variable speed drives are a much more precise means of controlling the speed and power intake of electric motors.
For Poole's Pies, replacing the 315 kW screw compressor's slide valve control with ABB’s low harmonic ACS800 drive delivers power savings of 11 percent. The compressor motor now operates efficiently at lower speeds between 1500 and 3600 rpm.
Moreover, ABB’s 15 kW standard drive, ACS550, now controls the fan that forces cooling air over the condenser, yielding a 3-percent decrease in energy consumption for every 1-percent drop in speed. The result is the fan uses from 20- to 30-percent less power than it did before the conversion.
Although the full load efficiency of screw compressors is generally good, part load performance can be poor, says Brian Seward, spokesperson for installer, Seward Refrigeration.
“With variable speed control of the compressor at Poole’s Pies, we now have the best of both worlds, good efficiency at both partial load and full load.”
Refrigeration systems decrease temperature by removing heat rather than by adding cold. To circulate cold liquid refrigerant and absorb heat from the space to be cooled, mechanical vapor-compression refrigeration systems rely on key pieces of hardware, such as compressors and fans, to move pressurized refrigerant.
Variable speed drives help keep farm produce fresh
Based in Washington State, USA, JMC Ventilation Refrigeration specializes in the design and manufacture of custom ventilation and refrigeration systems for potato and onion storage. JMC is using ABB’s advanced drive technologies to provide precise, on-site and remote environmental control that helps ensure vegetable quality and reduce mass loss (shrinkage), while saving energy.
Company founder Joel Micka says: “Each potato and onion variety has its own temperature and humidity requirements for optimum quality and our systems need to hold very accurate settings – within a tenth of a degree – to allow food storage up to 12 months.”
To achieve this, JMC uses ABB standard drives to control fan-motor speed and airflow, keeping temperature and humidity at precise settings. Incorporating drives enables the fans to run more efficiently by matching air volume precisely to demand. When air demand decreases, the variable speed drive slows the motor down, saving energy and helping farmers maximize their sales margins.
In a typical installation, used in an onion store, six 18.6 kW/25 hp drives use about 19.2 kWh at 100 percent speed. If the fans are reduced to 50 percent speed in the winter, when storage volumes are down and the outside temperatures are low, each of the fans use about 2.8 kWh. All six fans at 50 percent speed use less energy than one fan at 100 percent speed. If the six fans are kept at 50 percent during a one month period, savings of 70,848 kWh or $5,667 per month can be made.
Even more important than the energy savings is the safety and efficiency the new systems provide through remote control and monitoring, because storage facilities are often located many miles from the main offices. Says Micka: “With the old systems using traditional motor contactors, if the motor current increased to a level that was too high, it would trip and shut down the motor and then shut down the whole system until someone checked on the building and restarted it.”
With the optional intelligent ethernet module, the drives can be monitored remotely, either through a modem or via the Internet, allowing faults to be quickly diagnosed and solved, without the need to visit the storage site. Communications can be set up to send an alert via e-mail to the operators to warn them when a fault trip occurs. JMC integrates all of the systems components, refrigeration units, fans, drives and doors, into a network operated through a remotely accessible control panel.
ABB (www.abb.com) is a leader in power and automation technologies that enable utility and industry customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in around 100 countries and employs about 120,000 people. ABB has a full range of business activities in China, including R&D, manufacturing, sales and services, with 15,000 employees, 27 joint ventures and wholly owned companies, and an extensive sales and service network across 60 cities.