compressed air efficiency: you can do it too! · • cac marketing chairman • international...

Compressed Air Efficiency:You can do it too!

May: 2018

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PresenterRon Marshall

• Consultant MCAC• 38 year Employee of Power Utility• 21 years Technical CA Support• CAC Instructor• CAC Marketing Chairman• International Trainer UNIDO

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Coming Up

• Why should we care about Compressed Air?

• How efficient is compressed air?• Three secrets to optimizing your system• Steps in identifying problems• Example projects• Next Steps 4

Contrary to common opinion………

Compressed Air is not free!It’s one of the most inefficient energy

sources

Why Care About Compressed Air?

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Most industrial plants have a compressed air system

Energy costs are usually unknown


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Questions:

Do your compressors have energy meters?Do you know how much air you use?


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Fact:

Compressed air is one of the most expensive and problematic ways to transfer

energy


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Air Compressors Have Poor Natural Production

Efficiency

Every 7.5 hp power input to the compressor results in only 1 hp output at the

compressed air end use!• Biggest output is heat• System characteristics affect input to output ratio


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Example

Source: www.compressedairchallenge.org – 5 day a week, 2 shift, $0.10 per kWh

Compressed Air Motor30 cfm in for 1 HP out5.7 kW in for .8 kW out

$2,330 (compressed air) vs. $390 (electric)

7 times as much

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http://www.compressedairchallenge.org/

Half this energy is wasted

Studies show only 50% actually makes it to the end use

• Leakage - 20 to 30 %• Artificial Demand - 10 to 15 %• Inappropriate Use - 10 to 15 %


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Fact:

Compressed air is one of the most expensive and problematic ways to transfer

energy

Knowing this, do you care?Often people don’t


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Ensuring there is enough compressed air for production activities is the highest priority

Energy efficiency is often secondary

Keeping the system running is key


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System reliability and stability can be improved

Compressed air problems can be solved

All this can be done in an energy efficient way through optimization


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Three Secrets to Optimizing CA

Secret 1: Compress the air more efficiently

Secret 2: Use less compressed air

Secret 3: Use the heat of compression for something useful

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• Compressor control and selection

• Dryer types and controls

• Filters

• Piping

• Compressor and Plant pressure reduction

• Operating hour reductions

Compress Air More Efficiently

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• Timer control – turn off during non-production

• Reduce flow

• Leaks

• End uses

• Drains• Lower Pressure

Use Less Compressed Air

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• Space Heating• Boiler and Process Pre-heat• Air dryer purge

Recover Heat

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• ExampleMeasurement shows 85 kW input and an average system flow of 200 cfm

System specific power is 42.5 kW per 100 cfm

If we know that an optimized system should be consuming 20 kW/100 cfm we know there is a potential for improvement

First Step Baselining: Identifying problems

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• ExampleMeasurement shows the system flow is 100 cfm with no production machines running

Leakage load is 100/200 = 50% of the average flow

If we know that an optimized system should have only 10 cfm of leaks so we know there is a potential for improvement

Baselining: Identifying problems

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Case Study

• Railway Wheel Foundry• Poor compressor control• Poor dryers and filters• Small storage size• High leak levels• Baseline 4,000,000 kWh• $148,000 electrical cost

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Case Study

• Railway Wheel Foundry• Bag house leakage – 550 cfm• Uncontrolled desiccant dryers• Cabinet coolers• Leakage and non-productive load

estimated at 65%

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Case Study• Railway Wheel Foundry

• VSD control and Sequencing• Two stage compressors• Cycling dryer and dual filters• Refrigerated coolers• Larger storage capacity• Savings 1,800,000 kWh – 45%

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Case Study

• Railway Wheel FoundryAdded benefits• More reliable system• Less maintenance• Better pressure profile• Automatic operation• System monitoring

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Case Study

• Highway Bus Manufacturer• Load/unload control• Aging compressors• Large storage size• High off shift flow levels• 1,700,000 kWh• $112,000 electrical cost

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• Highway Bus Manufacturer• Breathing Air Purifiers - continous• General leakage• Uncontrolled dryer purge• Leakage and non-productive load

estimated at 81%

Case Study

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• Highway Bus Manufacturer• Two stage compressor - VSD• Leakage repair – 250 cfm• Controls on purifiers – 200 cfm• System monitoring• Savings 962,000 kWh – 49%

Case Study

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• Highway Bus ManufacturerAdded benefits• More reliable system• Less maintenance• Better pressure profile• System monitoring

Case Study

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• Large Aerospace• Mismatched compressors for load

profile• Aging compressors• Future Production increase• Very high peak flows• 4,800,000 kWh - $242,000

Case Study

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• Large Aerospace• Centrifugals 3 x 350 HP – 1500 cfm – Blow-off• Pressure fluctuations• Actual load 750 cfm average• Peak flows forecast 5,500 cfm• Specific power 75 kW/100 cfm

Case Study

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• Large Aerospace• Four new compressors- VSD• Leakage repair – 200 cfm• High pressure storage 2 x 2000

gallon 300 psi• Sequencing control• Savings 4,100,000 kWh – 86%

Case Study

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• Large AerospaceAdded benefits• More reliable system• Increased peak flow• Better pressure profile• Automatic operation• System monitoring

Case Study

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Where to find help

• Compressed Air Challenge Training• Local Power Utility• Local compressed air vendors• Your own staff

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SummaryKeys to Optimization

Realize compressed air is an expensive source of mechanical powerLook to the 3 secretsCompress, dry and filter more efficientlyMinimize waste through leakage, artificial demand and

misuseUse the heat of compression for somethingBaseline your system to find out how efficient you areRealize many successful projects have already been

done, learn from them!Get help 34

Speaker Info

• Ron Marshall• Chief Auditor• Marshall Compressed Air Consulting• [email protected]• 204-806-2085

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mailto:[email protected]

compressed air efficiency: you can do it too! · • cac marketing chairman • international...

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