Energy technologies: Compressed air systems

Compressed air has a number of quick payback energy saving options. With Emsol, you should be able to achieve savings of between 10% to 60%.

Overview

Air compressors are typically only 20% efficient and, therefore, alternative options should always be considered. For example, replace a pneumatic pump with an electric pump when practical and use an air blower, or broom, instead of a compressed air hose.

With compressed air, the aim is to reduce the need for compressed air, to stop leaks diligently and use efficient compressors. All compressed air efficiency improvements should result in less volume of air compressed, to a lower pressure and with high efficiency compressors.

Many businesses underestimate the amount of energy wastage from not stopping air leaks sooner than later. Leaks typically use 20%-50% of compressed air. Leaks should be tagged every six months by a qualified surveyor using an ultrasonic detector. When the cost of the survey is more than the savings, then extend the survey to once a year or once every two years.

A common and large energy saving option is to use (Variable Speed Drive) VSD on one screw compressor. This saves between 10% and 50% energy during part load operations when replacing a fixed speed screw compressor. The VSD compressor should always lead in order to increase energy savings.

Another energy saving option is to increase the size of air receiver, particularly if air pressure is more than 6.5 bar or there is no VSD compressor in the system. Use cold inlet air to the compressor. A rule of thumb is 1% energy savings with every 3oC decrease in inlet air temperature.

How we can help

Emsol’s accredited compressed air auditors provide walk-through and in-depth compressed air system audits. Funding is available, so talk with Emsol about this most widely utilised industrial energy consumption.

 

Our services in this area include:

  • assessing the appropriateness of current compressor setup
  • investigation of heat recovery opportunities
  • specific electricity consumption data logging of each compressor.

These steps enable us to provide you with:

  • a review of supply system performance and efficiency
  • recommendations to improve supply
  • a complete engineering findings and recommendations report.

The Energy Efficiency and Conservation Authority (EECA) has an option to fund an energy saving study specifically for compressed air systems (CAS). Emsol can help you with this opportunity by using our specialist knowledge and training to complete a report of energy saving opportunities.

Are you having air compressor problems?

Emsol frequently visits sites that have reached their limit with compressed air systems – production increases and the system cannot keep up. This is the prime time to get the whole system reviewed to minimise its life cycle cost.

 

Air compressors are small in CAPEX and big in OPEX. A $40,000 air compressor used frequently will cost more than $400,000 in electricity and servicing in less than ten years. Before buying a compressor, it is worth optimising the system design to squeeze down its OPEX.

A complete evaluation of the compressed air system determines air use patterns over the whole year, considers receiver sizes, dryer types and numbers of compressors. These all have a significant effect on this large OPEX, which in turn have the same effect on your business profits.

 

Tips

Some of the more effective tips for saving energy with compressed air systems include:

  1. Tag leaks using a qualified surveyor and stop them leaking within one week.
  2. Use air blower or broom in place of air hoses.
  3. Ensure air users are not excessive; reduce frequency of bag house filters.
  4. Install large receiver adjacent to large air consumers.
  5. Remove pressure restrictions such as under sized filters.
  6. Reduce pressure to 7 bar or less.
  7. Use cold inlet air to the compressor.
  8. Use VSD on one screw compressor for part loads.
  9. Otherwise, use reciprocating compressor for part loads.
  10. Use fixed speed screw compressors only for 80%-100% full load.
  11. Replace pneumatic equipment with electric alternatives when practical and safe.