Energy Savings in Screw Type Air Compressor

Compressed air is usually considered your fourth utility, after heating fuel, electrical energy, and water. It is not uncommon for compressed air to be the most expensive utility.

This US DOE publication is a pretty good document to review in your quest to improve overall efficiency:

http://www1.eere.energy.gov/manufacturing/tech_assistance/pdfs/compressed_air_sourcebook.pdf

Dear Doorman,

Yes I too agree for your comment, But even to generate air we have spend huge amount of electricity which is nothing but MONEY. But thanks for your artical which will help me in adding some good tricks.

Regards

Anil

I suggest not to produce air anymore. Last I heard there was lots and lots in the atmosphere.

Here is your plan:

1. switch compressors off

2.watch

3. wait

4. tell the guy that complains first that you only talk to his boss

5. don't talk to the boss because

6. when your boss comes tell him you are busy because the compressors are not running

7. try to survive a week

8. after the week show energy bill to your boss

9. savings accomplished!

Now since we have no idea what your process parameters are we can not guide you more.

You already have these options:

1. fix all leaks
2. know your requirements
3. reduce pressure
4. reduce run times
5. switch off at least when not needed
6. fix all leaks
7. if more than two compressors run alter the starting times so they dont start together

Ideasmith,

Thanks for your plan. I am here to save energy not to hear your non sense lecturre kindly dont underestimate any ones question funny.

<sigh>

Outcome based education... Turning out thin-skinned humorless individuals who view observational critique as a personal attack.

<unsubscribe from this brand of nonsense>

Did you buy the most efficient compressors you could find, or the cheapest compressors you could find?

Which one of the 7 points did not suit you?

I vote for 1. know your requirements.

Touche!

I would go through the facility putting right any leaks before doing anything else, Mildred.

Yes crabtree.

You are right arresting the leakage is prime source.

Well? Have you done it yet?

First the standard factory output pressure. If you don't need that high of a pressure lower it. There will be about a 5% savings for every 10 psi you can drop it. Will also increase the life of the compressor.

Reclaim the heat for winter. I have no idea of how your after cooler is vented but venting it indoors during the heating months will save energy on heating.

Rethink your usage. Where electric motor can be used do so. It takes 7 to 8 hp motor to generate air to run a 1 hp air motor continuously.

Thanks Ozzb

For a start I'm going with everyone else, stop any leaks.

We did have an over capacity for air, so when not needed compressors shut down and restarted in rotation. Loading was also cyclic to even out wear.

By pure good luck we acquired two 2^nd hand units ½ half the capacity of the original units. (It helps when you buyout your competitor.) These operated only when the main units were cutting in and out on a regular basis. Basically to keep what was running as near to full load as possible.

The PLC program to manage them was a bit tricky. But I enjoyed writing it.

All in all the modifications saved several £K per week.

BEE gives clear guidelines and check points to conserve energy in various utilities in industry and I suggest follow those guidelines and get benefit. Of course readers have given their views and they are largely in line with those guidelines.

Good luck

PLEASE MENTION FURTHER DETAILS LIKE-RATED PRESSURE, OPERATING USER END PRESSURE, LOAD/UNLOADING TIME AND PRESSURE, NO OF HOURS OF OPERATION/YEAR.

FURTHER, IS IT THAT YOU HAVE 4 X 1000 cfm COMPRESSORS? iF SO HOW MANY OPERATE AND HOW MANY STANDBY. PLEASE ALSO MENTION AMBIENT TEMPERATURE, TEMPERATURE OF SUCTION AIR, ALTUITUDE, LOCATION IF PSOSSIBLE.

IS ONE DRYER OF 15000 cfm COMMON, WHAT TYPE OF DRYER IT IS

WE CAN ARRIVE AT MANY OPPORTUNITIES

REGARDS

Helo friend..

I can suggest following

1: Remove all leaks. In practice major cause of wastage is through this leak only. It says that 30% energy is lost due to leak.

2: Reduce the pressure. Normally people set the compressor for its normal working pressure- even it is not required. Check the system requirement and re-set your composer for optimum pressure. More pressure means more leakage, more current by motor.

3: Minimise pneumatic tools.

4: Provide an automatic load/unloader mechanism

5: Provide a VFD ( Variable frequency drives). u can find a good saving.

6: Make a good maintenance schedule and allocate best technicians

7: Ensure a clean intake

8: Train / motivate all employs about energy conservation. Involve them for this.

9: Check the rating of your motor and optimise the HP rating. Sometime u may be using a motor having bigger capacity compared to what actually required.

10: Devide and schedule the load as far as possible.

11: Check whether u are running a compressor having capacity that not required at all. ( Say u need an air of 50CFM with 6Kg/cm2 , but running a compressor having capacity of 200cfm and 12Kg/cm2 )

12: Finally derive a method to measure your saving.

A lot of good suggestions have been mentioned already.

1. Convert one compressor to "variable speed compressor" that will take care of variable plant load will save a lot of energy. Other compressors will take care of base load.
2. Please check for motor efficiency. If the motors are old and do not mention motor efficiency, then replace the motors. The cost of motors will be recovered within a year.
3. Hire a good energy consultant who will identify all the opportunities by studying all the parameters related to compressed air generation as well as utilization. This will help in a great way. Normally plant people would not have time as well as expertise for going after such a comprehensive project.

Dear sir,

Thanks for your kind response and time. If you know any energy consultant in Karnatka state india can you please give the detail.

Contact Devki consultants, Baroda. They are the best and I have personal experience in this regard. Even Atlas Copco would guide you about the variable speed compressors. We saved abour 30% after a study showed high percentage of "Unload" running of one compressor

PLEASE NOTE THAT YOU ARE YET TO SEND THE SYSTEM DETAILS AS I HAVE ALREADY ENQUIRED (THESE ARE NOT ANY SECRET AND I CAN JUST SAY-IF YOU MENTION TYPE OF MANUFACTURING INDUSTRY YOU ARE). INFACT YOU SHOULD HAVE ALREADY DONE IT AS FEW MEMBERS HAVE JOCULARLY ASKED YOU TO DO SO. OK, NOW IF YOU ARE SERIOUS-SEND A REQUEST AND TAKE FURTHER YOUR QUERIES TO ASK FOR VISIT. ENJOY SAVING ENERGY AND ENABLING THE TECHNOLOGIES THEIR PATENT

Email Removed - CR4 Admin

If I remember correctly the Atlas Copco compressors are the modulating type. This means that the motors tend to slow down when the demand goes down. They don't switch off.

Observe the operation and if this is happening frequently, you may be able to switch off one unit all together, or set it at a pressure level where it comes on only at peak demand times.

How are you using a 1500 cfm drier with 4000 cfm compressors? The moisture removal becomes meaningless. You could switch this off, or get a larger capacity of air drier.

Do some research, the facts are here

This is the best one

https://www1.eere.energy.gov/manufacturing/tech_assistance/pdfs/compressed_air_sourcebook.pdf

http://industrial-energy.lbl.gov/node/165

https://www.compressedairchallenge.org/

http://www1.eere.energy.gov/manufacturing/tech_assistance/compressed_air.html

http://www.energystar.gov/buildings/sites/default/uploads/tools/compressed_air1.pdf

http://www.nrel.gov/docs/fy99osti/24939.pdf

Good Luck, Old Salt

How about adding additional air receivers (tanks). More storage equals less loading/unloading cycles and may allow your compressor to shut off (not just unload) for periods. Helps smooth demand.

We have an ejector that uses a large volume of air in a burst about every 15 minutes. We throttled the inlet to the receiver so that three compressors don't load up and fill it right away. We let one compressor slowly fill it. As long as it fills within 15 minutes, were fine.

Screw type compressors do not require receivers. I believe this is because the compressors are modulating type, and the output is smooth ( as compared to piston types.)

If the consumption is Fluctuating ( both in terms of pressure and flow), it is required to give a receiver. This is must for energy saving point of view also. Isn't it?

No, I think you are wrong.

The output of air is constant,because it is a screw type compressor, and as it is a modulating type, the flow will increase or decrease as per the demand.

A receiver is necessary in reciprocating type of compressors as the output fluctuates.(sinusoidal)