Air Compressors: Savings Found on the Supply and Demand Side

Producing compressed air can be expensive, but it is necessary for pneumatic systems.  And a large part of that expense is wasted energy, in the form of heat.  Waste will add to your overhead and affect your bottom line.  EXAIR has a line of products to help reduce air consumption at the point-of-use to save you money.  This would include replacing open-pipes and tubes with EXAIR Super Air Nozzles and Super Air Knives.  But, let’s look at the supply side inside your compressor room.  The air compressor operates at about 10% efficiency where most of that loss is in a form of heat. 

Wouldn’t it be nice to recover some of that expense?  You can.  By equipping your air compressor with a heat recovery system.  These systems are designed to recover the loss of heat for other uses.  Today, they can recover somewhere between 50% for liquid-cooled compressors to 80% for air-cooled compressors.  The heat can come from the after-coolers, the electric motor, the “heat of compression”, and the oil cooler.  This reclaimed heat can be used to heat water, warm rooms, pre-heat steam systems, and dry parts. 

Let’s create an example.  A company has a 100 HP air-cooled compressor that is running 8 hours per day for 250 days per year.  The heat recovery system will be able to reclaim 60% of the heat to warm city water in the plant.  If the electrical cost is $0.10 per KWh, we can calculate the savings.

Annual Savings:

100 HP * 0.746 KW/HP * 0.6 (reclaim) * 8 hours/day * 250 days/yr * $0.10/KWh = $8,952.00 savings per year.

In practice, reclaiming the maximum percentage may not be cost effective.  Your company can determine the best percentage for heat recovery by calculating the Return on Investment (ROI).  I wrote a blog post that can help you estimate (Click Here)

As mentioned above, EXAIR saves you money and increase efficiency on the demand side.  EXAIR has engineered nozzles to help reduce compressed air usage.  The following is a quick calculation by replacing an open-end blow-off with an EXAIR Super Air Nozzle.  If you have a ¼” (6mm) copper tube, it will use 33 SCFM (935 SLPM) of compressed air at 80 PSIG (5.5 bar).  As a common replacement, EXAIR uses a model 1100 Super Air Nozzle which will use 14 SCFM (396 SLPM) at 80 PSIG (5.5 bar).  With a simple tube fitting, you can mount the ¼” NPT Super Air Nozzle to the end of the ¼” copper tube.  If we use the same pretext as above, we can find the annual cost savings.  With an air compressor that produces 5 SCFM/hp, we can get a cost savings with the Super Air Nozzle.  The difference in air flow at 80 PSIG (5.5 bar) is:

33 SCFM (copper tube) – 14 SCFM (Model 1100) = 19 SCFM savings

Annual Savings:

19 SCFM * 1 HP/ 5 SCFM * 0.746 KW/HP * 8 hr/day * 250 days/yr * $0.10/KWh = $566.96 savings per year per nozzle.

Whether it is on the supply side or the demand side, companies are looking to reduce or reuse the wasted energy to have a more efficient compressed air system.  The heat recovery system is a bit more complex, but should be considered.  The EXAIR engineered nozzles are more simplistic, and they can give you a return on your investment in a short period of time.  If you would like to discuss how to improve your compressed air system from the supply side to the demand side, an Application Engineer at EXAIR will be happy to assist you. 

John Ball
Application Engineer

Twitter: @EXAIR_jb

Photo: Idea by Saydung89Pixabay License.

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