Ricoh saves £100,000 with plant-wide drives project 08 August 2011
Office equipment manufacturer Ricoh reports savings of more than £100,000 per annum on energy costs at its production plant in Telford, since installing ABB variable-speed drives (VSDs).
Ricoh energy specialist Andy Smith explains that the 52-acre site, which employs 750 people over its three production buildings, has a large number of air handling units (AHUs), as well as water circulation pumps and compressors, contributing to a utility spend of £1.25 million per annum.
He says that the plant initially trialled two hired ABB drives – one on a pump and one on an AHU – to prove their ability to cut back on energy consumption. "The results were very favourable, encouraging us to evaluate all possible motor-driven applications on site for their energy saving potential," says Smith.
"Our project prioritisation process evaluates criteria such as CO2 saved, technical complexity, risk and return on investment," he explains.
Having identified VSD installations as among the keys to energy saving, because of their simplicity and payback, he says the firm embarked on a programme of retrofits, 90% of which have now been implemented.
Smith says a total of around 70 drives now run a variety of applications around the site, with an average payback time of around six months per installation.
He also says that Ricoh has improved control over several of its processes. An example is the laboratory, where manufactured toner is tested. To achieve optimum tests, temperature and humidity must be constant to within 0.5oC, which has been achieved by using an ABB drive to control air flow.
An ABB drive-controlled humidifier also ensured that humidity varies by no more than 1.5in. "An important feature of the ABB drive in this application was the flux optimisation," comments Smith. "Even at 50Hz, with no speed reduction, this reduced the power consumption from 5.5 kW to 3 kW." And running at 35 Hz, the power consumption was further reduced to just 1.6kW, providing a payback of just three months.
As Ricoh's experience of using ABB drives has increased, the company has been applying drives in more applications. Says Smith: "We use three drives to synchronise two conveyors with a 22kW plastic granulator that grinds plastic parts for recycling. Linked to a PLC, this allows us to run the granulator on-demand. Run time has been reduced by 95%, dramatically cutting energy use and increasing equipment service life."
He also refers to the drives' supervised relay output function, which allows them to control motors dependant on the status of connected equipment, and Modbus compatibility, which allows control and monitoring of applications over a PLC network.
"The timer and constant speed functions have proved very useful to us," says Smith. "Combining these features, we can run the AHUs at varying frequencies over the seasons. In many cases, we run AHUs at 45Hz in the summer, 30Hz during winter and at 35Hz during other periods, all automated within the drive."
Incidentally, Smith also rates the ABB drives' sleep mode, which is programmed to put the drive into a 'PID sleep' mode whenever there is no demand from the process.
"The latest ABB drives now have energy calculators that display total energy consumption on the control panel screen," says Smith. "We are using this to increase energy awareness among staff by showing just how much energy applications such as granulators actually use."
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