Taking control of energy efficiency

In an effort to reduce costs and energy consumption, manufacturers are undertaking maintenance programs incorporating stringent testing and maintenance of systems. Katherine Crichton reports.

In an effort to reduce costs and energy consumption, manufacturers are undertaking maintenance programs incorporating stringent testing and maintenance of systems. Katherine Crichton reports.

WITH climate change the hot topic on everyone’s lips, going ‘green’ is the new black, and while some question the commitment of industry to reduce their footprint on the environment, compressor manufacturers are proving that sustainable manufacturing can also help Australian businesses save money.

An increased conscientiousness about energy consumption, combined with developments in compressed air system technology and new standards for compressed air systems (MEPS) is driving a growing trend towards compressor management and control.

Simon Wood, national sales manager, Boge Compressors, says advances in frequency control variable speed motor technology and compressor control are two key parts of the modern, more efficient compressed air system.

“The current vogue of frequency control has brought about positive changes to save energy and reduce the carbon footprint.

“Frequency controlled screw compressors provide a low carbon technology that works strictly in accordance with the compressed air demand by producing the exact volume of compressed air at the pressure required.

“Frequency control minimises idling time and evens out air demand fluctuations. This in turn reduces compressed air energy usage and associated energy costs,” Wood explained.

“Compressor control is another area that has really improved in the search for better efficiency.

“Nowadays, the controllers on the compressors are more sophisticated. That, in conjunction with more intelligent multiple compressor controllers can provide users with detailed reports making data on energy efficiency readily available.

“These modern controllers can also connect to a remote PC for reporting and visualisation.

“Compressor control also means that systems can be optimised and visualisation then provides hard copy evidence of usage, costs and savings. Remote monitoring, unheard of ten years ago, is now very much part and parcel of a modern installation.”

According to Wood, when an energy management system is implemented, the manufacturer can target continual improvement through control and on-going monitoring of the compressed air system.

“They can do this irrespective of changes in demand on a daily, weekly or even monthly work load.”

Water works

While the debate about oil-free and oil-injected screw compressors rages on, manufactures are revisiting the construction of both these systems and are enhancing their design for optimum efficiency and minimum oil consumption.

A notable example is the idea of oil-free water injected screw compressors which Richard Harris, medical and oil-free product manager, industrial air division of Atlas Copco says is the future of the industry.

“Water injection screw technology has been around for almost ten years in terms of a commercial viable product, but it’s never been a totally oil-free system. You needed oil to lubricate the gears and bearings,” Harris told Manufacturers Monthly.

“Through extensive development the technology has been refined to the point where it is a truly efficient and environmentally friendly technology,” he said.

While water as a lubricant is extremely aggressive, it is claimed to have a superior capability to remove heat efficiently at the source, while the low temperature of the compressed air can reduce stress on components, better ensuring long life.

Harris says to combat the aggressive nature of water as a lubricant, especially on traditional materials such as cast iron, polymer ceramic materials were used for the compressor rotors, stainless steel for the shaft, with a bronze aluminium alloy for the casing.

“As the element bearings are water-lubricated and slide on water, oil lubrication is not necessary.” he said. “Combined with a variable speed drive, which means no gearbox is required, we can produce a machine which truly consumes no oil whatsoever over its lifetime.”

Price of efficiency

Both Harris and Hall say one of the biggest changes a manufacturer faces when it comes to energy efficiency is the justification of the capital investment cost.

Hall says it goes without saying that a technology designed for low carbon output carries a price premium, but advises that manufacturers should consider the bigger picture.

“The initial payback time should not be the primary consideration. Moving to energy efficiency technologies has to be a long term investment – the manufacturer will continue to enjoy sustained energy consumption savings long after the payback period has lapsed,” he said.

Harris echoes this sentiment and believes many compressor users that are conscious about energy consumption will be aware of how much a system costs to run and will soon see an acceptable ROI if they do the sums.

“Depending on how many shifts a company runs, there can be a ROI in as little as 18months or 2 years.

“Variable speed drive compressors are also coming down in size, with 5kW versions available suitable for mechanical workshops and people can see savings even from those small units,” Harris explained.

However like with any technology, these compressors will only provide an optimum energy efficient solution when used in the right application.

Both men advise manufacturers to conduct a full energy audit when considering energy efficiency compressors.

“To establish the benchmark, a system must be comprehensively audited by evaluating generation, treatment, distribution and process usage,” Hall said.

“The generation evaluation may include identifying factors such as the number of compressors being used to meet the demand, the quality of maintenance and so on. Even seemingly small factors can unnecessarily increase energy costs.”

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