Manufacturers of the compressors also make their contribution to reduce the energy consumption of compressed air generation comprehensively by 30%.

Kaeser Compressors Inc. offers users a PC-supported compressed air audit, which determines accurately the actual air requirement for new systems and also for existing installations.

Erwin Ruppelt from Kaeser Compressors says, “The more transparency a compressed air system offers over cost saving potential, the closer all those involved come to throttling the energy consumption related to the generation of compressed air by a potential one third advantage in terms of company results and the environment.”

Through the audit all savings potential is exposed and the compressed air installation can be configured for maximum reliability, energy efficiency, and also optimized for future requirements.  Modern compressor controls that communicate with industry PCs, allow for precise data collection and evaluation, and form the basis of a complex system management that can reduce energy consumption significantly. This includes existing installations.

Compressed air technology is capable of even more. Erwin Ruppelt says, “In the domain of heat recovery, more valuable heat energy can be saved. A 100% of the drive energy supplied to a compressor is converted into heat. Up to 96% of this energy can be used a second time, either for heat purposes or as process heat.” He says that specific use of compressor waste heat allows for a reduction in consumed electrical energy, but also the heat energy requirements of a company.

Potential savings

Possible efficiency increase with specific heat recovery profiles using screw type compressors is shown by example of a mill operation. Comparing the year 2007—when compressor waste was still not being used — and 2011 says a lot. Due to gas heating, a total of 552,000 kW-hr was saved by this company. The savings is equal to 36% of total heating costs for the company. The following annual average was possible: the use of 52% of the compressor output for heating purposes a second time, the top measurement value was 71%.

Innovative developments in compressed air technology promise a reduction in energy costs. For example, pneumatic turbine motors, applied here instead of the traditional vane motor, makes use of the expansion process of the compressed air. Thus, the energy medium is used far more efficiently, and the machine’s air requirements are reduced by one third.

The turbine motor picks up additional points with its unsurpassed output (kilogram/kilowatt) — in terms of power to size ratio it is half the size of a vane motor.

Dubbelde says, “By exchanging a vane motor the size of a fist for turbine motor of equal size, I can double motor output on the spot.”

The turbine requires no lubrication, and there are no wear parts, this only increases the economic viability of a turbine.

Prof. Weiss states, “Today, compressed air is more efficient that ever before, but if the factor of heat recovery is not considered, a company will see no economical advantage.”

In the future he predicts, “Compressed air systems could be used more and more in the decentralized monitoring of excess renewable energy. With the available Kaeser compressors and the innovative GET turbine generator of Deprag, this CAES (Compressed Air Energy Storage) short-term conservation of wind and solar energy — even if the kW rating is small — could be a prelude to a new field in application of compressed air technology.”