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By Atlas Copco Oil-Free Air Division, Vice President of Marketing, Ignace Cappuyns

** Reader query:

“We need to invest in compressors for our beverage plant. How do we know which to choose, taking into account high performance, energy efficiency and filter costs?”**

Compressed air is used by manufacturers all over the globe to cool PET and glass as part of the manufacturing process. With today’s high and still rising energy costs, energy efficiency is of greater importance than ever before and a topical theme worldwide.

Frequently more than one type of compressor is required with oil free compressors for sterile zones involving food and beverage filling, and standard compressors for end of line packaging equipment.

If a compressor stops, the whole plant comes to a halt. Downtime has immense value to a company. Increasingly companies are looking for calibrated measurement systems and we offer unrivalled energy efficiency in screw compressors.

Compressed air equals 10% of the energy used by all industry as a whole. 80 terra watt an hour per year (Twh/yr) in Europe, which equals 10 million tonnes of C02.

The greatest improvement of all can be made by detecting leaks and so improving energy efficiency. Parabolic antennae developed by Atlas Copco a few years ago pick up leakages using ultrasound.

A more recent development is that of VSD (variable speed drives), which save between 25 to 35% of energy used. All of our competitors have now incorporated this option.

Finally, recovery of waste heat and heat exchange is becoming increasingly important with a number of plants using the warm water resulting from cooling compressed air for washing bottles and equipment. In fact, only 5% of energy is used in compressing the air, by far the majority is used in the required cooling.

So, air compression is a rising cost and as fuel costs rise it can no longer be regarded as just an overhead. Globally we have agreed to reduce emissions between 2008 and 2012 (by 8% in Europe, 7% in US and 6% in Japan). To make this achievable we need to use intelligent controllers – to optimise and control the installation and give lower lifecycle costs. By putting into practice all the methods listed above, around 32.9% or roughly one third of energy costs can be saved.

Atlas Copco puts leading edge technology in the marketplace. The commercial battle is not just to look at the purchase cost (just 15% generally of lifetime cost), but overall energy use and the cost of filters.

By using the superior screw element we keep specific energy requirements as low as possible. We have reduced the consumption of air compression machines by 6% over six years, which equates to 1% per year, and in kilowatt hours is really significant.

As innovators and pioneers in the air compression field, the company aims to ensure better productivity for its customers and ultimately better profitability. Market demands include: * A fast payback on investments * Operation in harsh and dusty environments * Reliability in extreme heat - some areas such as the Middle East have plants operating in temperatures of up to 50°C * No loss of production * Cool, dry and clean compressed air at the lowest possible cost.

*Patented energy efficient screw * The new GA can work at maximum temperatures of 46°C and has a Class F insulator and B rise. It also needs to breathe, and for this we have a two step dust protection system.

This filter lasts 8,000 hours, which is twice that of the previous generation filter. The GA Variable Speed Drive sucks outside air in, then controlled by the speed drive, oil is used to cool the radial cooling fans. But cooled air means water droplets and hence corrosion, so the compressor also contains a water separator operated using centrifugal force. A valve opens according to the amount of water collected, while an integrated dryer – the FD310 ensures no moisture remains to cause corrosion. Warm air incoming at 30°C is cooled via a refrigeration process and water drained away. Dry air is achieved through the heat exchanger to prolong the lifecycle of the compressor.

Sensors are used to measure both temperature and pressure and are controlled by an electronikon regulator, which can text an alert to change the oil or replace the filter. This can now operate in 31 languages, including Japanese and Chinese.

The GA VSD therefore delivers total control and reliable high performance, giving a fast payback on investment.

*Low noise = lower costs * “In the development process of the new GA, we made substantial efforts to reduce all types of losses, whether flow related, mechanical or electrical. The latest design techniques such as Computational Fluid Dynamics (CFD) analysis were used to meet these objectives,” said GA Product Manager at Atlas Copco, Paulo Pereira.

He was keen to point out that because the system produces less than 50% of the noise of previous models, it no longer needs its own compression building but can be part of the plant floor, reducing the need for extra piping and compressed air leaks. This has been achieved due to the variable speed drive fans, which have reduced the sound drastically. The decibel level is now below 71 and no other compressor company has been able to achieve this. In addition, no other compressor on the market has this lifetime for its filters – which is extremely important in the overall cost to the consumer.

As for heat exchange – with this new model 94% of the energy can be reused – to increase the heat of water going into a boiler or for showers for staff and as a general energy resource. Investment in energy resources can therefore be recovered in two months and for the overall cost of the compressor, in two years. The first of these machines were delivered in May 2008.

As a larger company, we can afford to invest in research and from experience it will take from two to five years for others to react and produce similar products. Companies looking for a sound energy saving investment would find the new GA range best for non food and beverage areas (end of line packaging etc). The Z range which received ISO 8573-1 certification in 2006 ensures that no traces of oil can be determined in the air stream.

Compressors are relatively long lived capital goods with an average lifetime of 13 years for compressors between 10 and 90 kw/h and 16 years between 90 and 300 kW. They operate on an average of around 3,500 hours per year.

Driving down energy costs is our mantra and one of growing importance to beverage companies worldwide. Today unrivalled energy efficiency is the key to everyone’s success.