How can I reduce compressed air energy consumption?

[u/Think_Assistant_8798]

I’ve been looking into ways to reduce compressed air consumption on production equipment, and I’m curious what has actually worked for people in practice.

Obviously, Leaks are the place to start, but beyond fixing leaks, where have you guys seen the biggest savings?

Lowering pressure? Better sizing of cylinders and tubing? Switching off air to parts of the machine when they’re not running? Monitoring consumption? etc...

Also curious how you normally identify where the air is being wasted in the first place. Do you measure individual machines or components, or mostly look at the overall compressed air system?

I´m interested to hear what changes made a noticeable difference in practice rather than just looking good on paper..

[u/_ask_me_about_trees_]

Fixing leaks are the biggest thing. You would be amazed how much energy a tiny leak eats up. Then when you're done chasing leaks start chasing leaks again.

If you ever get to a point where you dont have any leaks then you will likely only be able to reduce energy consumption by moving to a variable speed unit or changing the way you dry your air.

What kind of dryer are you currently using?

[u/u3b3rg33k → u/_ask_me_about_trees_]

hahaha. step 1: don't use air

/s

but seriously. if you can do without hydraulics/air, do without.

[u/Ok_Combination_9136]

Where are you located? USA & which state? Lots of cool incentives that will pay you to do this.

As for lowering energy consumption…

- FIX LEAKS (as you know, this is #1 but I’m obligated to say it)

• increase useful system storage to limit load cycles
  
• lower pressure settings
  
• determine actual compressed air demand and build accordingly

The next big challenge is fixing artificial demand… take a look around your shop/production floor and identify how air is actually being used vs how air should be used. Artificial demand is a huge issue in any facility.

PM me if you have any questions!

[u/Yrk89]

Hay que tener en cuenta el consumo vs lo generado. Además la distancia entre el compresor y el punto de consumo. Si el compresor, secador,filtros de línea están con sus mantenciones al día y no están saturados. Luego ver si la red de aire es muy antigua y de que material es.ya que el galvanizado genera óxido al interior y perdidad por fugas. Otro punto a considerar son las curvas,codos y restricciones de la red de aire. (Se debe mantener el.diametro de la salida del compresor.

[u/LazloHollifeld]

Fixing leaks will have the biggest RoI for energy savings. Beyond that figure out what the absolute minimum pressure is before things start to come off the rails, then set the pressure slightly above that. Lowering the PSI will raise the overall CFM delivered, thusly saving you more energy.

Then beyond that it’s load balancing. VSD/Flow Controller/Modulation etc.

[u/CrustySailor1964]

Three things; leaks, leaks and leaks. There are readily available tables that specify the volume of air lost through orifices of various sizes. Notably (easy to remember) a 1/4” diameter hole will exhaust 100 CFM at 100 PSI. That is nominally the air produced by a 25HP rotary screw compressor. Little tiny leaks don’t sound like a big deal but their effect is cumulative.
Furthermore, leaks don’t have to be ‘external’ and audible to ruin your day and ravage your wallet.
It is not uncommon to have shot out piston seals in pneumatic cylinders that just puke air into a muffler that silences its escape. It is also not uncommon to have old underground piping that is supposed to have been isolated or removed but still leaks.
In an ideal world, when your compressor pumps up and shuts off (or modulates) the pressure in your system should remain constant. You should be able to walk throughout your facility and hear nothing. Yes, that’s a challenge for sure and perhaps a greater challenge is convincing management that the leakage is an issue that merits the production delay and expense to resolve. My response to that is the statement that repairing the leak is a one time expense and leaving the leak is an every time you press the button expense.
Evaluating the efficiency with which your compressed air is delivered from the point of production to the point of use is important as well and depending on how many systemic leaks you have may merit replacement as well. That is typically a capital expense and will absolutely be a top down evolution.
After that, as already mentioned, you need to reduce the cost to produce the compressed air and a variable speed screw compressor is an excellent choice.

[u/RaisinTheRedline]

As everyone has said, leaks make a tremendous difference. This is a table showing the wasted kWh per year for a two stage compressor, based upon pressure and the physical the size of the leak and assuming the system is pressurized 24/7.

Another thing to consider is whether or not your facility is paying significant peak demand charges on your electricity bill. If you are, and your operations are consistent enough that your peak demand periods are consistent, you can try to avoid having the air compressor running at those peaks to reduce the demand.

[u/yoball]

Years ago, a US Steel mill in pittsburgh had so many leaks that they decided its more economical to add another screw compressor than to have the union employees fix the leaks, so we sold them one. I cant remember the size, but it wasnt small.

[u/DddtBrand → u/yoball]

i’ve got a similar story where i’m at. local company bought an extra 50hp unit because it was cheaper to buy and run that than have their leaks fixed, and they are only using the air for their controls…

[u/sprbiker]

Leaks for sure but..... Regulators! Most equipment is designed to run on 100psi or less. The same tool can use much more cfm at higher pressures

[u/u3b3rg33k → u/sprbiker]

also worth noting that lowering system pressure as close to the peak regulated pressure required saves the most energy. regulators throw away the difference - there's no energy recovery there.

[u/MrMotofy]

Put a shutoff on each machine/device and cut off the line when not using it. It allows easier maintenance and safety. Then from that point you could shut everything off, then start leak detecting and work from there.

[u/nsula_country]

Leak detection... We use an ultrasonic leak detector. We have over 1800 hp of air in our plant.

[u/EngineeringSad8558]

How much horsepower are you running?

[u/searchinglulu]

Start by checking the operating pressure. A lot of systems run at higher pressure than they need. You would be surprised by how much can be saved by making this simple adjustment.

Also worth checking if the cylinders are oversized and whether air is still being supplied when the machine is idle. Both can waste quite a bit, especially with frequent cycles. To this day, I don't understand why End Users are not more demanding of OEMs on this...

For monitoring, I'd measure at machine level rather than just looking at the compressor. Makes it much easier to spot where the air is actually going.

I'd say measure first, make a few changes, and compare. Otherwise you're just guessing.