Bidvest Laundry Group is reducing costs and improving efficiencies while using less energy, thanks to the intelligent use of two forms of energy-saving technology.
“Our commercial laundries use huge amounts of steam to heat water, and to dry and iron linen and garments. Generating all that steam requires a constant supply of heat and water, and that we generate by coal or electricity and by drawing fresh water and.or condensate,” says Collin Field, national operations manager at Bidvest Laundry Group. “Both from the cost and environmental points of view, we are constantly looking for ways to use that energy more efficiently.”
In Bidvest’s case, the boilers at several of its large laundry facilities are powered by coal. Both pieces of technology were installed to make better use of the energy produced by the coal, and thus reduce the amount of coal consumed per month.
In the first instance, the company installed aquatherm technology, which transfers heat from rinse water discharged into the drainage system via a “radiator” to the fresh clean water entering the system. This heat transfer raises the temperature of the clean water by up to 30º Celsius, thus reducing the amount of steam the boiler needs to produce to achieve correct wash temperatures and thereby reducing coal consumption.
“Instead of literally throwing heat energy down the drain, we are now reusing it,” says Mr Field. “It has given us a saving of more than 10% in our coal usage in certain plants.”
The technology is installed at the facilities in Cape Town, Mogwase, Durban and Johannesburg.
A second initiative aimed at improving the performance of the boilers themselves has been the installation of variable speed drive technology. This system simply ensures that the boiler is fine-tuned to respond to the actual minute-by-minute demand for steam from the factory. Traditionally the boiler is controlled by an operator and the controls are managed via visual inspection, a process that can result in delayed reaction times.
There are a number of advantages to this new technology, Mr Field explains. One is the saving of coal by matching the heat of the fire to the demand for steam. Another is the reduction in the electricity used to the run the fans by varying their speed in line with demand—previously, the fans simply ran at a uniform speed all the time.
A third benefit of this optimised boiler operation is that the steam supply to the laundry is consistent. This optimises the performance of the roller ironers, tumble-driers and other finishing equipment, thus improving overall productivity and efficiency.
Variable speed drives on coal-fired boilers have been installed at Bidvest Laundry Group’s facilities in Johannesburg and Cape Town. In addition, most of the laundry equipment in operation has this technology thereby minimising electricity consumption.
“The variable speed drive gives us a further reduction in our coal bill of more than 10%, not to mention the savings on electricity and efficiency gains,” concludes Mr Field. “Overall, I am pleased to say that these two initiatives have reduced our energy consumption by up to 20% in certain plants.”