How much do air leaks really cost?

How much do air leaks really cost?

The highest cost associated with air compressor ownership, is not the cost of the compressor, or the cost of preventative maintenance, but the electrical cost associated with running the compressor itself. With the electrical cost being the most expensive portion of compressor ownership, can you really afford to run a compressor unnecessarily? Well, let’s examine this a little further.

First, we should look at how electrical companies charge for your electricity. The standard billing is measured in Kw/H (Kilowatts per hour). Electrical rates vary greatly depending on time of day, location, and total usage, but for our example we’ll use a rate of 16 cents per Kilowatt Hour.

The next step is to figure out how much electricity we’re using; our example is using a 5hp compressor. To convert horsepower to kilowatt, multiply the horsepower rating by .74. So, 5 horsepower x .74 gives us 3.7 kilowatts.

Getting closer now, we’ve got to figure out how long the compressor runs. We’ll use a conservative rating of %50. So, during an 8 hour shift, we’ll assume that the air compressor is running for 4 hours. If we work with a single shift operation, and based our example on 5 days a week, 52 weeks a year, we come up with 4 hours a day x 5 days a week x 52 weeks per year  = 1040 run hours per year.

And finally, 1040 hours per year x 3.7 kilowatts x 16 cents per Kw/H = $ 615.68 per year.

Doesn’t sound like much, and perhaps it’s not, however, we are talking a small compressor, in a small shop, with relatively low run time. However, does it really need to be this high? At just about any shop you walk through, you can hear air leaks. Many times people think these leaks aren’t anything to be concerned with, and that they are so small, that they won’t matter, I disagree. I think it’s fair to say, that an average shop would have the equivalent of a 1/16” holes worth of air leaks – from hose quick disconnects, leaking fittings, leaking tool, leaking drains, or a host of other sources. Think about it this way; a 1/16” of an inch is about the size of the tip of a pen, really not large at all, but at this size, and at 125psi of pressure, there is waste of 7.9 CFM worth of air. So, how much is 7.9 CFM? Well, remember that 5hp compressor we started our example with? Well, this compressor delivers an average of 17.5 CFM, so there is %45 waste of the total capacity.

It should be noted as well, that the amount of air that's wasted is exponential when compared to the diameter of the hole; at 1/16th of an inch, at 150psi, the leak rate is 9.1CFM, at 1/8th of an inch, that number more than triples to 37.3CFM!

So, in the system above, if the leaks were eliminated, there would be a 45% reduction in electrical usage, so the $615.58 annual costs would drop to 338.62.

How many horsepower worth of compressed are do you have? How many shifts do you run? How much can YOU save?

At Air Compressor Works, we work on compressors from ½ a horsepower up to 300hp and larger, and our staff of highly trained service technicians and salesmen are constantly on the look out for ways to make your compressed air system more efficient. Give us a call, and let us find ways to save you money on your compressed air system.

 

Wayne Holtzclaw, Technical Service Manager, Air Compressor Works, Inc.

PVC Piping for Compressed Air - A Disaster Waiting to Happen

Man, that PVC pipe we got from Home Depot was really cheap and easy to put up.  Now we're ready to get this body shop up and running.

Cheap and easy now could turn into expensive and deadly down the road. PVC pipe is not designed for compressed air. 

In fact, it's not even legal (unless you bury it or encase it in a shatter-proof material, which gets rid of the whole cheap and easy part). 

There are very good reasons:

1.  The maximum temperature of most PVC pipe and fittings is 140F, and even at 110F you derate the pressure rating in half (so a pipe rated for 150 psi is now only good for 75 psi).  Most small piston compressors can have air coming out close to 200F or higher, especially in the summer.

2.  PVC becomes brittle when exposed to the oil vapor in the compressed air and UV light.

3.  A PVC pipe cracking or failing at 100 psi can easily kill or injure you or your employees.

Don't just take our word for it - here is what the pipe manufacturers themselves have to say about it:

Charlotte Pipe:  "WARNING! Never test with or transport/store compressed air or gas in PVC pipe or fittings."

GF Harvel:  "GF Harvel's PVC and CPVC piping products are "rigid" thermoplastic materials. As a result, GF Harvel does not recommend the use of PVC or CPVC piping products for the testing, transport, or storage of compressed air or gases.
Warning! The use of rigid thermoplastic plastic piping in compressed air or gas applications can result in severe bodily injury or death."

Silver Line Plastics:  "PVC PIPE IS NOT RECOMMENDED FOR AIR PRESSURE"

Don't let cheap and easy now cost you a lot later.  Don't use PVC pipe for compressed air, and if you have it replace it immediately.

Clean out your strainer!

Many companies that have compressed air have timed electric drains on their tanks.  They look like this:

They are very convenient, because you don't have to remember to drain your tank every day.  However, the convenience is a double-edged sword.  They're sometimes so convenient that the maintenance person forgets to maintenance them at all. 

You are supposed to clean out the strainer to make sure it's not clogged.  Most of the failures we see from these drains are because the strainers were clogged.

You should check the strainer weekly.  It's very easy to do.  Here's how.

1.  SAFETY FIRST - Make sure the power to the compressor is disconnected - at the the disconnect - don't rely on the pressure switch.  Make sure the drain is unplugged from it's electrical supply.  Make sure you drain all of the pressure out of the tank.

2.  Find the strainer on the drain.  It should be piped between the solenoid of the drain and the tank.  There will be nut you can remove without unpiping it.  On some strainers it's on the end, and on some it's in the middle.

3.  Remove the nut, take out the mesh inside, clean out the mesh, and put everything back together.  Turn everything back on, and pressure test it by having the drain manually open (usually there's a button on the drain).  Check for leaks.

That's it.  It should only take a couple of minutes, unless the nut is stuck on there. 

If the mesh is gone, you can pick up some cheap from a local hardware shore.  Cut it to size, roll it into a cylinder and put it in the strainer.

If you don't have a strainer - get one.  You can pick them up nearly anywhere and they're cheap.  Just check the psi rating to make sure it meets or exceeds the psi rating of your tank.  If you can't find one, we sell a 1/2" one for $20 (our part number is YBS50).  You know what - I'm knocking down that price 20% to $18, if you like this on Facebook or share it on Twitter.

This simple step can prevent a drain failure.  In some air systems an unnoticed drain failure can be a disaster - the tank will fill up with water and you'll shoot it downstream, damaging all of your equipment.

Never skimp on maintenance - you'll pay for it later.

Optimizing Your Compressed Air System

Optimizing Your Compressed Air System

According to the US Department of Energy, manufacturers spend over 5 billion dollars per year on the energy to power compressed air systems (link here).  Optimizing your compressed air system can save 20-50% of that cost.

At Air Compressor Works, we suggest the that best way to optimize your air system is have free system assessment done, and then move on to a full Air Demand Analysis if needed.

Why throw your money away for no reason?  Get a free analysis today.