At Alutec in Germany, sustainability, the environment and energy efficiency are used as benchmarks for (almost) everything. The same applies to its supply of compressed air, which the company obtains through an Atlas Copco contracting agreement. In 2012, the entire compressor station was replaced by latest generation machinery, saving the company at least 70 000 kWh of electricity every year. Alutec uses the waste heat from the energy efficient compressor for cleaning parts and for heating.
Headquartered in Sternenfels, in the Enz district of Baden-Württemberg, the company manufactures aluminum moldings, primarily for the automotive industry and its suppliers. “Most of the compressed air is used to blow out parts after pressing to remove chips and lubricants,” explains General Manager Willy Kretz. “The contact points and clamping devices, tool turrets, robotic arm grips and measuring station also need compressed air.”
Raising energy efficiency – step one: the compressors
“We use GA+ compressors from Atlas Copco's latest generation,” says Siegfried Kälber, responsible for operating technology. In the machine room, there is a GA 55+ FF and a GA 75+ FF, both fixed speed, plus a variable speed drive GA 90 VSD FF. “The base load is primarily handled by the 90,” explains Kälber, “the fixed speed compressors are only used at peak times.”
All three GA compressors have an integrated refrigerant dryer and use the environmentally friendly refrigerant R410A. This does not harm the ozone layer and reduces the dryer's energy consumption by 50%.
Alutech uses an ES 130 V master control system. This utilizes the compressors to full capacity so that the combination of machines that has the lowest possible specific energy requirements is always used.
Contracting eliminates risk
As Alutec has concluded a contracting agreement, the entire system is owned by Atlas Copco. This means that Alutec only buys compressed air and is not involved in maintenance or repair of the compressors. The service is extremely satisfactory: “Even if a compressor should break down, Atlas Copco will provide a replacement within 24 hours,” says Willy Kretz, General Manager of Alutec, “and we have always been given good support with technical issues.”
As part of the renegotiation of the contracting agreement, the entire station was replaced with the new GA machines in 2012. “As a result, we are now saving at least 70 000 kilowatt hours of energy over the year for compressed air generation,” estimates Kretz.
Raising energy efficiency – step two: heat recovery
The compressors are equipped with a heat recovery system and are connected to recover heat inhouse. “This allows us to put to good use more than 90% of the heat produced from generating compressed air,” reports Kretz. The hot cooler water is used to heat the processing and rinsing tanks for the cleaning system. In the winter, excess heat helps to heat the workshop.
Raising energy efficiency – step three: conserving energy
Ultrasound devices have been in use for two years to prevent leaks in the compressed air supply network, and pneumatic valves that close automatically have been installed on the processing machines; these cut off the air flow when the machine is not in use. “These measures alone have enabled us to lower the energy requirements for our compressed air generation at weekends from 250 to 50 kilowatt hours,” underlines Kretz.