Compressors adapt for economical air supply

Edited by the Engineeringtalk editorial team Oct 28, 2005

Jaguar Cars has saved a substantial amount in energy costs by replacing piston compressors with a more efficient combination of fixed and variable speed compressors from CompAir.

Jaguar Cars, the luxury car maker, has saved a substantial amount in energy costs by replacing piston compressors with a more efficient combination of fixed and variable speed compressors from CompAir.

The decision to change came after the existing compressors at Jaguar's Whitley Engineering Centre were data logged to assess their energy usage.

Although 18 years old, the piston compressors were operating reliably, supplying compressed air for a variety of functions across Jaguar's design and development facility at Whitley, Coventry.

With 3000 people working on the site, the compressed air system serves a variety of general functions including operation of rolling roads and a range of air tools.

Because of the system's reliability, there had been no question marks over its performance until it was suggested during a routine service visit by a CompAir distributor, that a modern system could offer considerable energy cost savings.

Although Jaguar's Whitley Engineering Centre does not have a vast requirement for compressed air, it does need to be available on demand 24/7 so the system is always running.

CompAir pointed out to their customer that the existing system was simply not cost effective in energy terms because with large variations in demand it was incurring major wastage by continuously generating the output to meet peak requirements.

To prove the point, the system was data logged to show the savings that could be achieved with a new system.

The sum was substantial so from Jaguar's point of view there was no question about replacing it.

Like any major energy user, the company has seen baseload wholesale electricity price rises of over 50% so it represented simple good practice to reduce those costs, as well as looking at ways of conserving energy as part of its corporate environmental responsibility.

The system recommended was a combination of a CompAir L45SR variable speed drive compressor together with two L37 fixed speed machines with a SmartAir intelligent management system.

The SmartAir controller constantly monitors demand to select the appropriate combination of compressors to meet it.

In operation at Jaguar, the speed regulated compressor provides the base requirements, with its variable speed switched reluctance drive system matching variations in demand throughout the working days.

It is only when demand peaks that the fixed speed compressors come into play to provide the additional output.

Also included in the package is a CompAir CS Range static oil/water separator, essential to meet environmental regulations which call for oil content of condensate to be reduced to legal disposal limits.

By reducing the oil concentration in the collected condensate, a larger volume of clean water - up to 99.9% of the total condensate - can be discharged safely into the environment.

With a CompAir Assure Plus service plan in place, Jaguar has also seen a substantial reduction in its annual service costs, which have virtually halved.

This combined with the energy cost savings will mean a payback period of under two years for the new compressors.

The L37, chosen by Jaguar, is one of a range of high performance and efficiency oil-lubricated rotary screw compressors manufactured by CompAir.

Designed to operate at very low noise levels, the L Series compressors are simple and easy to install and with quick access service points, minimise service downtime and costs.

Manufactured under an exclusive licence from SR Drives, CompAir's LSR Series uses a digitally controlled switched reluctance DC drive which eliminates the energy consumed by conventional compressors during periods of unloaded running.

In comparison, LSR technology produces savings in excess of 25% in energy and operational costs.