Auditing your way through wasted energy consumption

The Federal Government might have delayed its Carbon Pollution Reduction Scheme (CPRS) until 2013, but the decision has not stopped the rise in electricity prices.

Following recent electricity price-hike announcements, including an increase in NSW by as much as 42% over the next three years, manufacturers are being forced to combat their energy usage head-on.

Air compressor systems are arguably one of the highest elec tricity consumers on the factory floor, said to use up to 30% of the plant’s total energy consump tion, and thus should be a focal point when looking at ways to improve efficiency.

In preparation for the inevitable electricity price increases, the compressors and pneumatics industry has been working for years to develop ways to reduce running costs and improve environmental protection.

Champion Compressors executive manager of sales, service and marketing, Mark Ferguson, says the industry has experienced a change in emphasis towards energy savings and is now completely focused on improving the operating efficiency and control of compressors as well as managing the way compressed air is used.

Ferguson adds however, before energy savings can be made, manufacturers need to under stand the costs of running and using compressed air.

“Because electricity was so cheap, most manufacturers didn’t really consider the costs of run ning an air compressor; whether they had the right compressor, whether it was too big, whether it was set at the right pressure or whether the quality they were getting out of it was appropriate for the application,” Ferguson told Manufacturers’ Monthly.

“There was definitely a lack of awareness about how much energy is wasted while operating these systems and it is only in recent times we are seeing manufacturers coming to us looking for ways to improve power consumption.”

Air auditing

According to Atlas Copco business line manger of the comany’s Industrial Air Division,  Wo, commissioning an energy audit should be the first point of call when looking to reduce a compressor’s running costs.

“When we customers we almost insist, particularly for larger compressors, on doing an audit of their air compressor so we can size the system correctly and show them the potential savings they can possibly make,” Treble said.

“Energy costs can represent over 70% of a compressor’s life cycle costs and generating com pressed air can account for over 40% of the plant’s total electrici ty bill, so the potential savings are significant.”

Atlas Copco offers a complete compressed air audit system which is performed over a seven-day period.

The company’s auditing process relies on an Air Measurement Box survey tool which is a device that measures the compressor’s incoming cur rent. It is said to take an electri cian about 30 seconds to install.

“On a compressor you have an electricity supply line and on that supply line we place a data logger that measures the incoming current and records it in one-second intervals,” Treble explained.

“We leave the data logger in place for a week, then download the data to our software which is then interpreted and converted into a flow profile.”

The flow profile is used to analyse three main areas: whether the compressed air sys tem has air leaks; determining if the compressor is the correct size for the application; and pre senting potential energy savings to the customer.

Using the collected informa tion, the company compiles a detailed report, including cost analysis, graphic representations and recommendations for improving system performance.

“Once we interpret the airflow profile we can then simulate that profile against various types and sizes of compressors,” Treble said.

According to Ferguson of Champion Compressors, his com pany, which conducts an average of eight to ten energy audits a month, uses the assessment to tailor compressed air equipment and control systems to a factory’s air usage profile.

“If they’ve got a constant demand for compressed air that doesn’t vary we can put a com pressor in that suits their needs and run it in the most efficient operating mode,” he said.

“But if they’ve got a widely varying demand for compressed air then they need a compressor with a different type of control. And what this enables us to do is to make sure the equipment we put in matches their profile.”

Boge Compressors national sales manager, Simon Wood, says the unfortunate thing about energy audits is manufacturers often think one is enough, when in fact significant transforma tions are only possible when conducted on a continuous basis.

“We recommend getting an energy audit done about every quarter. We need to monitor for example if leakages have decreased or if the compressor is actually the correct size for the application,” Wood said.

“We also always do a post audit, so after the equipment has been put in, if we say it’s going to save the plant $10,000 then we’ll do a post audit to prove it’s saving most of what we’ve said.”

Wood says operators are sur prised when told how much air they are wasting, which is generally between 25 to 30%, and consequently the majority of people take action based on the recommendations.

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