Energy can represent over 70 per cent of a compressor’s lifecycle costs, so optimising energy consumption has become a priority for many organisations as the ensuing savings can be substantial.
Atlas Copco’s Newcastle Sales Executive, Graeme Hall, works closely with local public and private sector enterprises to ensure they are making the most of the latest technology to maximise efficiency and minimise energy consumption.
Newcastle’s John Hunter Hospital is an example of one such organisation that relies on Atlas Copco to keep them up to date with efficient, state-of-the-art air compressors and control equipment solutions in order to ensure the seamless supply of oil and contaminant-free medical air throughout the hospital.
According to Peter Allen, John Hunter Hospital’s GNS Hub Manager — Area Facilities Management Unit, Atlas Copco has been providing the hospital with excellent advice and cost-effective air solutions for the past four years.
“When the Royal Newcastle Hospital was replaced by the Royal Newcastle Centre on the grounds of John Hunter Hospital it gave us the opportunity to replace some of our aging plant with modern, energy efficient equipment,” Allen said.
John Hunter Hospital was originally equipped with two reciprocating compressors that, due to the technology of the day, were over-sized, very inefficient, unreliable, and expensive to run, he added.
“After extensive investigation, Atlas Copco’s fail-safe, contaminant and oil-free air technology was deemed to be the most suitable for our needs.
“Based on our requirement for guaranteed air supply, two ZT 45 Atlas Copco compressors and one variable-speed drive ZT 50 VSD compressor were installed.”
The variable speed drive on the system’s primary compressor, the ZT 50 VSD, is very effective, Allen said, as it enables the compressor to cycle in line with demand to deliver the required amount of air.
He added that this feature has not only reduced running costs but will also reduce the through life maintenance costs as the compressor runs only to meet demand and not exceed it like the older ones did.
“Reliability is another performance aspect that has improved dramatically. The old compressors required constant maintenance, whereas the Atlas Copco compressors run issue free.
Atlas Copco works closely with the hospital to monitor the compressors’ performance, whether it’s preventative maintenance or through devising operational solutions to meet specific concerns, Allen said.
“Being a fully automated system meant it offered us truly set-and-forget simplicity and it has certainly delivered that, as we haven’t touched it since it was installed.”
“Initially, our involvement started with the installation of two air cooled 45 kW ZT 45 oil-free rotary tooth compressors and a bigger 50 kW ZT 50 VSD version, which between them gave the hospital a 200 per cent redundancy factor and reduced energy consumption by over 35 per cent.”
The ZT 50 VSD compressor is ideally suited to sites like John Hunter Hospital as air supply is automatically adjusted to meet demand, Hall added, which means energy is saved during no-load and low-load operation and oil vessel blow-off, plus VSD enables narrow pressure band operation, which constantly reduces the overall system’s working pressure.
“To further maximise savings for the Hospital we developed a preventative maintenance programme that covered all aspects of operation, from consumables through to regular and major servicing.
“During the preventative maintenance review the issue of managing the regular cycling of the two ZT 45 compressors was raised and our advice was sort on how best to simplify the process.
“Prior to the review maintenance personnel would manually switch from the primary variable speed drive ZT 50 compressor to one of the ZT 45 back-up compressors on a rotating basis as a means of regularly testing their availability. The main concern, however, was that if supply didn’t revert back to the Variable Speed Drive compressor optimum operating efficiency wouldn’t be achieved.
“For Atlas Copco the solution was simple as we offer a range of state-of-the-art ‘ES’ controllers.
“In the case of John Hunter Hospital I recommended the ES 130 central controller, as it is capable of handling all machine sizes and types with unlimited control capacity and artificial intelligence processing.
“The ES 130 was hardwired to each of the three compressors and then through the easy-to-use software options and the ES 130’s touch screen the hospital’s maintenance personnel were able to programme a run cycle that automatically switches from the ZT 50 VSD to the ZT 45 compressors for 12 hours, once a week.
“On completion of the 12-hour run cycle, the ES 130 automatically shuts down the smaller compressors and re-engages the ZT 50 VSD as the primary compressor.
“By taking the human element out of the equation the ES 130 controller has given maintenance personnel operational piece of mind that the back-up compressors will work when needed and that energy savings delivered by the ZT 50’s Variable Drive will always be optimised,” Graeme said.
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