When we talk about saving energy we are really talking about saving money – that power isn’t free now is it?
Up to 70% of the total cost of ownership on an air compressor is buying the electricity – it can be less if you buy smart… But it’s a good indication of the lifetime cost of power.
The aim of the game is to use as little power as possible in order to achieve your goals.
Here are some ways to cut your compressed air power bills.
Use the Off Switch
Unless you are a 24/7/365 operation, you don’t need compressed air 24/7/365. Turn your compressor(s) off when you aren’t working. Depending on when you are open you might only need air for 60-100 hours a week rather than the full 168 hours there are in a week.
Turning the thing off when you are shut down could see a 20% reduction in your power consumption.
‘Free’ Heat Source
To me, one of the highest art forms in industry is taking waste product and turning into a useful input for another process.
Compressing air gives of heat – quite a lot of it. Turning that from a waste product into a useful input could cut down your power bills somewhere else – you could use it to augment or replace a conventional hot water unit for example or you could pump that warmth into a work space keeping your employees warm.
Don’t Use it if you don’t have to…
Are you using compressed air for applications where it would be more efficient to use something else?
I thought so…
Compressed air is frequently used for cooling or applications where a lower air pressure could be used. In many situations it would pay off to change from using compressed air to using a more efficient and economical air source.
Bonus Tip: Use a more efficient compressor. Gardner Denver and Quantima make excellent energy efficient air compressors that can reduce the total cost of ownership compared to many traditional models.
If you are looking to reduce the energy costs of your compressed air system then the best investment you can make is in an efficient air compressor. Contact Pye-Barker on 404-363-6000 or email us at firstname.lastname@example.org to see just how much you can save on your energy bills.
Some of our clients keep their compressed air systems in pristine condition. Others would be horrified if they shut down their workspace for 12 hours and went around listening for leaks. Others could do that and their team would shrug.
I hope you and I are on the same page about this – we can’t really afford to be wasting money in this day and age. Competition is fiercer than ever and every cent wasted in inefficient operation could be the difference between life and death.
Some of our clients waste thousands of dollars a year with an inefficient air system
With that in mind I thought I’d share with you just what can be done to improve your air compressor’s efficiency so that you can free up some more money and either put it in the bank or use it to make your operation even more efficient.
Fix Your Leaks.
Honestly, I can’t stress this enough. If your air system is leaking it is money down the toilet. To make it more real – go to the bank take out $1,000. Go to the nearest bathroom, rip up the money drop it in the bowl and flush.
You wouldn’t do that. So why wouldn’t you fix the leaks?
70% of the total lifetime costs of your air compressor is electricity and in a typical industrial installation up to 30% of the energy consumed is wasted – it sounds expensive and it is.
The cost of a single of your compressed air, that you just spent electricity to produce, can run between $200 and $2,000 per year.
Get Your Drains Right.
If you are still using the older condensate drains – especially the mechanical types – remember they are going to leak. And leaks should be fixed. They often end up discharging a lot of compressed air when they discharge the condensate.
Smarter drains discharge on a timer. They open for 10 seconds every 5 minutes. But the problem is that they do this even if there is no water to discharge (or not enough water to discharge for the full 10 seconds). If there is air coming out, it’s a leak – costing you money.
Compressed air is expensive and both mechanical drains & ‘smart’ drains leak. Think about the number of drains in your system.
It’s time to switch to “zero loss” drains. They only discharge water. The capital cost to put these in is fractional compared to the costs of air leaks.
Eliminate Pressure Drops
Pressure drops are when compressed air flows through a restriction in your system and is the difference in pressure before and after the restriction. They only occur when air is flowing through your system.
You can measure your pressure drops only when your air is flowing; the more air flowing the more obvious the pressure drop. You need a measurement of air pressure at your air compressor and at your end use machine(s).
If you can reduce the pressure drop by one psi, in many systems that could be a savings of $100’s of dollars per year depending on the size and number of air compressors you are running.
If you need some help identifying how you can optimize your compressed air system, give the team at Pye-Barker a call on 404-363-6000 or email email@example.com we’ll conduct a no cost no obligation analysis of your system.
A good air compressor should only be noticed when it isn’t working. The rest of the time it hums away doing its job so that all of your factory’s vital functions can continue on, as expected.
Downtime is frustrating not only because something you expect to work isn’t but also for many businesses we service, an air compressor being down means no product is going out the door.
The downtime is costing you in maintenance and profit as well as upsetting the guys on the floor.
Here are the questions we get asked over and over again about air compressor oil maintenance. Following this advice will save you a fortune in both downtime and repair bills.
Can I top off the existing compressor oil with another oil?
When you mix two different oils is you create a third oil. The resulting third oil’s chemical properties may vary significantly depending on the mixing ratio, 50/50, 90/10, 10/90, etc. The suitability of this new oil for your compressor is anyone’s guess.
Additionally, these different mixtures have never been tested in operating conditions for extended periods of time so the expected oil life is not predictable – so this just results in a need for more monitoring that could be avoided by using the right oil in the first place.
You place your compressor at even more risk if you mix your oils. Don’t do it.
What do you mean mixing your oils?
Mixing oils with different chemistries or mixing a PAO base oil with a Petroleum base oil can cause varnishing.
Varnishing can cause your compressor to run hot often leading to costly repairs and expensive downtime.
Mixing oils can cause solubility problems between base fluids. They could emulsify and/or lose viscosity. If soluble, the oil will behave as well as the worst lubricant, mineral lubricants shorten the life of synthetics. Which creates another unnecessary expense – faster oil change.
Will I invalidate the compressor warranty by using aftermarket oils?
It is recommended that you use the compressor manufacturer’s oil thru the warranty period. If there is a problem and you make a claim against the warranty, the oil will be tested. Contaminating one oil with another is typically grounds to invalidate a warranty.
How long will the compressor oil last?
This depends on several factors, including application, cleanliness of air and type of oil used. Use the following table to estimate how often you need to change your compressor oil
|Discharge||Aeon 4000||Aeon 6000FG||Aeon 9000SP||Aeon 9000TH|
|Up to 180F||4000 Hours||4000 Hours||8000 Hours||8000 Hours|
|180F to 190F||3000 Hours||3000 Hours||6000 Hours||8000 Hours|
|190F to 200F||2000 Hours||2000 Hours||4000 Hours||8000 Hours|
|200F to 210F||1000 Hours||1000 Hours||2000 Hours||6000 Hours|
Why do I have to change the oil anyway?
The short answer is oil oxidizes. Oxidization is the chemical reaction between oxygen in the air and the oil being forced together by mixing at high temperatures. Oxidation is the number one reason why the fluid must be changed out.
Oxidation of any PAO based fluid (Many compressor lubricants are PAO based) can lead generation to varnish formation in the fluid is allowed to run through the compressor without the presence of antioxidants. Oxidation by-products can accumulate in the fluid, become insoluble and collect on the surfaces of the compressor as varnish.
If the varnishing is bad enough if you turn the compressor off long enough for the oil to cool down – say for the weekend, the varnished oil will become a thick dense mass causing the compressor to lock up and not restart once the oil cools down to room temperature. Once the varnished oil has cooled down it turns into a thick mass and it cannot be cleaned out. Any piping containing varnish as well as the air end will need to be replaced.
As long as the varnished oil stays hot and in a liquid from the unit can be cleaned out using the Comp Clean product.
Obviously this can all be avoided with regular oil changes – so don’t let them slip through the cracks.
Oil Testing and Oil Analysis Reports
Pye-Barker Supply has free oil testing with a detailed analysis reports thru Gardner Denver Oil Services Laboratories, to get an analysis for your compressor just call 404-363-6000 or ask your technician the next time he is on site for a service.
Drive method is probably the simplest method of differentiating compressors.
The compressor, whether reciprocating or rotary, can be v-belt driven, direct coupled, or either of the above accompanied by a variable frequency drive. The simple v-belt drive is most commonly seen on the air cooled reciprocating compressor, and smaller rotary screw compressors. V-belt drives provide for versatility in selecting optimum speeds for the desired flow and pressure. Direct drive (coupled) compressors require that the air end be constructed to maximize the flow (CFM) for a given horsepower motor, or use internal gears to adjust the speed of the compressor to achieve this maximum flow.
Variable speed (frequency) drives adjust the speed for optimum flow and pressure by adjusting the frequency of the incoming power to the compressor.
The final method of compressor differentiation is by duty cycle. This determines the amount of time the compressor can safely run without shutting down for cooling.
Small air-cooled reciprocating air compressors generally are allowed to run 75% of the time and be idle for 25% of the time. This allows the components to cool between cycles. Rotary compressors and water cooled reciprocating compressors can run continuously 24/7, shutting down only for periodic maintenance.
Centrifugal compressors are also designed to run continuously 24/7.
Finally, cooling method be a determinant of compressor type. This is simple, as there are only two. Cooling can be either air-cooled or water-cooled. Rotary screw compressors, if air cooled, use a radiator-style cooler (heat exchanger) for both oil cooling and after-cooling. If water cooled, shell and tube type heat exchangers are typically used. Plate-fin coolers can also be used.
Air-cooled reciprocating air compressors will typically use a finned tube intercooler and the same for after-cooler. Some will use a radiator type for after cooler. Water cooled reciprocating compressors will typically use shell and tube heat exchangers for both intercooling and for the after-cooler.
Centrifugal compressors will generally be water cooled, and use shell and tube type coolers.
Compressor types can also be defined by lubrication, i.e. whether lubricated or non-lubricated. Non-lubricated compressors are usually referred to as “oil free”. ISO 8573-1 Class Zero (2010) provides for a purity level that ensures no oil is in contact with the compressed air, and typically indicates no oil is used in the compressor, at all. “Oil-less” is another nomenclature used to indicate no oil used in the compressor. Oil free and oil-less are about as good as it gets when it comes to quality of compressed air. (There are treatments available to remove impurities that are ingested through the intake of the compressor, but the compressor does not add any impurities to the air stream.) Both reciprocating and rotary compressors use special materials (TeflonR piston rings or coating of rotors, for instance) and sealing media such as water sealing between rotors. Timing gears are also used to keep rotors separated.
Lubricated air compressors actually inject oil into the compression chamber to provide lubrication for the moving parts. Piston compressors will provide lubrication to the cylinder walls, rings, and running gear (rods, crank, bearings, etc.) by one of two methods. The first is “splash lubrication”. The piston rod will have a dipper affixed to the bottom which dips into the oil in the sump and splashes it up onto the running gear and pistons. This is the most common form. Pressure lubrication is an alternative to splash lubrication. This incorporates an oil pump which forces oil into the moving parts through drilled passages within the compressor. It will also incorporate an oil filter to remove contaminants from the recirculating oil.
Rotary compressors use differential pressure to circulate the oil throughout the lubrication system. The oil is pulled from the sump and processed through the oil cooler to reduce the inlet temperature of the oil before being injected into the compressor pump (air end). It then passes through the oil filter to remove impurities from the oil. It is then injected into the air end where it lubricates the bearings and gears (if any), seals between the rotors to prevent metal-to-metal contact, and keeps the temperature within an acceptable range. It is then delivered through an air-oil separator to remove the oil from the air stream and store it back in the sump. This process allows for some oil carryover into the air stream.
Centrifugal compressors are inherently oil free as no oil enters the compression chamber. Lubricated parts are separated from the compression chamber by air seals and oil seals, separated by an atmospheric vent area.
“I want a quote on an air compressor”. This is how the conversation and subsequent negotiation begins. Our first response is “what size?” This refers not only to the CFM required, but also to the pressure required. Once these points are determined, the next question is “what type compressor?”
Compressor manufacturers offer a range of compressor types, each with pros and cons, depending on the customer’s application, specifications, and budget restraints. The compressors are broken down into various categories defined by: 1) compression method, 2) lubrication, 3) drive, 4) duty cycle, and 5) cooling method.
Compression method refers to the way the air is compressed. The earliest devised type is reciprocating or piston-type. This incorporates a piston sliding up and down within a cylinder compressing the air within the cylinder, and exhausting out the discharge valve. These reciprocating compressors can be air cooled or water cooled, single stage, or multiple stage, single acting or double acting. They can range from fractional horsepower up to several thousand horsepower.
The second type is rotary screw. This method uses helical screw rotors, male and female, in a continuous rotary motion, compressing the air within the housing. Most commonly, screw compressors are lubricated with oil flooding the rotors for sealing, cooling, and lubrication of the rotors, bearings, and gears (if used). The rotors are not timed by gears, but they are separated by a film of lubricating oil. These are used in heavier manufacturing where continuous duty is required. Rotary screw compressors are designed to run continuously 24/7 with shut down only for maintenance.
A third type of compression is by rotary vane. This method utilizes a series of vanes or blades arranged on a cylindrical rotor, rotating in an eccentric cylinder or housing. As the rotor rotates, the blades slide in and out of slots, allowing the volume between the vanes to be compressed. These units are also used in manufacturing facilities and are designed for continuous duty.
The fourth major classification by compression method is centrifugal. These compressors use an impeller with blades, curved to accentuate the air flow within a volute casing. They may be single or multiple stage depending on pressure requirement, and are typically oil-free. They are usually larger capacity and can be provided up to 10,000+ HP.
There are other compression methods available (diaphragm, rotary piston, etc.) but they are specialty/niche compressors.
More discussion on compressor types will follow in coming articles.