Possible Energy Efficient Alternative Solutions to Common Air Uses

Specialty Regulators - when lower pressure air is required at a fairly constant flow rate of 100-500cfm and 25-50psig, a pilot regulated valve or other specialty purpose regulator may be an acceptable solution. A receiver should be charged at line pressure and the lower pressure application is controlled by a flow control rather than a pressure reducing valve

Blowers - Low pressure, high volume applications such as dust removal or drying can benefit from a blower instead of compressed air. As little as 3psig can be very effective at a fraction of the cost of compressed air. Air from a blower is both warm and oil free which may help in certain applications.

Vortex Amplifiers - Where a blast or jet of air is required, vortex devices use the energy of the compressed air to entrain ambient air and put more volume to the application. Ratios of up to 20 to 1 can be achieved with these type of devices.

Boosters - use booster systems where additional pressure is required for a limited volume of compressed air. The booster can draw direct from air at line pressure or draw from ambient.

Benefits of a Compressed Air Analysis

• Determine real costs of generating air. Air as a utility is usually the most expensive within an industrial plant.
• Determine the actual in-field performance of compressor and quantify end uses of compressed air.
• Determine the actual volume of leaks in the facility.
• Potential for avoiding capital expenditure if you are facing buying new compressors or other equipment due to "load creep".
• Recommendations are for operating cost reduction which drop straight to the bottom line.
• May be opportunity to reduced maintenance costs.
• Use of independent third party will provide best results. Third parties are those who do not sell equipment (directly or indirectly) and do not have a vested interest in the results of the study.
• Contact NPPD for additional help through programs or to help find an independent third party.

Common Air Leaks and Misapplication

1. Optical scanning equipment clean off - small blower will do just as good at a fraction of the cost
2. Air hoses - loose or frayed clamps
3. Air lances and fittings which are casualties of the fork trucks and other equipment
4. Large Computer and electrical rooms - pressurized to keep out dust - small blower effective at less cost
5. Conveyor belt cleaning - again, use a small blower
6. Cooling machinery bearings- use a fan
7. Worn cylinder packing, worn "O" rings in solenoid and control valves, faulty PR valves or broken diaphragms, bleed- off vent holes in valves

Conclusions

No two air systems are alike and no two plants use air the same way. It is important to take specific plant operations and requirements into consideration when analyzing a system or proposing changes to an air system.

Compressed air is a unique utility for most plants since it is one of the few where the plant has complete control over the production, distribution and use of the utility. Most notably, steam systems generally fall in this category as well.

There are some additional items to think about with regard to plant air systems:

• In the average plant, 30% of the delivered air is feeding plant leaks.
• Eighty percent (80%) of compressor with inlet modulation are not delivering their rated flow.
• Average cost savings from implementation of recommendation from a plant air system study is 30%.
• An expensive solution is not always the best solution.

For additional information or assistance, contact Kelly Beiermann, Nebraska Public Power District.

Note: We encourage requests from Nebraska customers. Businesses outside of Nebraska will be directed to their utility for further information.

Source: Airometrix Mfg., Inc. 1999-2003