Small adjustments can reduce your operating pressure and energy costs while improving flow rates and output. Learn the final steps you can take to optimize your compressed air system and save energy costs. But, make sure that you also check out the first 5 things you can learn to "Save your Compressed Air System Operating Costs"
- Review Piping Infrastructure. Many systems aren't optimized.
A piping system design should optimize transfer of compressed air at the desired flow and pressure to the point of use. Increasing the size of a pipe from two to three inches can reduce pressure drop up to 50 percent. Shortening the distance air has to travel can further reduce pressure drops by about 20-40 percent.
The more flow through a pipe the greater the pressure drop will be. Pressure drop in a pipe increases with the square increase in flow, which means if the flow is doubled, the pressure drop will increase four times. Air distribution piping should be large enough in diameter to minimize pressure drop.
If your compressed air piping system was installed years ago when your compressor was much smaller, this might be an indication that the distribution pipes are too small. A quick guide is to look at the air compressor outlet size. If your distribution piping is smaller than your air compressor outlet size, then it may be time to get your FS-Curtis distributor in to evaluate your piping system. If up-grades are needed, FS-Curtis offers a modular, aluminum piping system that is easy to install and is a cost effective alternative to copper or steel piping.
- Change Filters Systematically. Not every once in a while.
Inspect and replace filters systematically to ensure the quality of your air and prevent pressure drops. Go beyond the air compressor and compressor room. There are several air-line and point-of-use filters within the facility. Those are just as important to maintain as the air compressor and air compressor room filters.
Your FS-Curtis distributor will provide you with a complete Filter Package located on your compressed air system supply side. Your process and type of equipment used will determine the level of air quality needed. If you are not sure what you need, ask your FS-Curtis distributor who can guide your selection using an industry standard selection chart.
- Recover Heat. Compressing air generates heat - reuse it!
It's simple physics that compressing air gives off heat, and as much as 90 percent of that heat can be recovered for use in your operation. For example, you can produce hot water for washrooms or direct warm air into a work space, warehouse, loading dock, or entryway. The savings can really add up.
How can FS-Curtis features and benefits help with this step? A simple heat recovery step can be making sure the hot air from your compressor room is directed into a nearby work space. If you have a larger rotary screw compressor with e-COOL® Technology, you could capture the exhaust air from your air compressor and ducting into your facility during the heating season. More aggressive heat recovery systems can be used to pre-heat water or process materials if you operate larger compressor systems.
- Emphasize Proper Maintenance. Ignoring maintenance costs more.
As with most industrial machinery, a compressor runs more efficiently when properly maintained. Proper compressor maintenance cuts energy costs around one percent and helps prevent breakdowns that result in downtime and lost production. Protect your reputation and profits with proper maintenance.
Your FS-Curtis i-Command® Touch Control will help monitor your compressor for items needing maintenance as well as sending signals showing maintenance alerts. Having your FS-Curtis distributor establish a scheduled service interval based on the number of hours your compressor runs per year will save you money in the long run. Take advantage of your extended warranty by using correct parts and lubricants at the correct time. If you skip service and have maintenance done, then you can expect that future warranty claims may be rejected. Just like you car, if you don’t take care of it, it won’t take care of you!
- Identify and Eliminate Inappropriate Uses of Compressed Air.
Inappropriate uses of compressed air include any application that can be done more effectively or more efficiently by a method other than compressed air. For example, high pressure air often is used for cooling or applications where much lower air pressure is required.
If you have a Compressed Air Leak Survey scheduled, the Auditor normally is looking for inappropriate uses of compressed air at the same time. Common missuses are: blowing off a work station with an air gun instead of using a hand brush; using an air stream as a personal cooler instead of a fan; plus many, many more ways.
The first step to reduce compressed air energy costs is to measure and monitor your compressed air system's energy consumption, flow rates and operating air pressure. Your FS-Curtis Distributor can help you with your understanding of your compressed air system through an assessment or audit of your system. The FS-Curtis distributor will provide you with a report, which will help you see how your air compressor(s) are being controlled,as well as how much energy, air flow and pressure is being used. Recommendations can be made to help you reduce your operating costs and return those losses back into profit for your business. Small adjustments can reduce your operating pressure and energy costs while improving flow rates and output. Here are 10 steps you can take to optimize your compressed air system and save energy costs.
- Turn It Off.
There are 168 hours in a week, but most compressed air systems only run at or near full capacity between 60-100 hours. Depending on your shift pattern, turning your compressors off during the evenings and weekends could reduce your energy bills up to 20 percent.
A suggestion to help you turn off your compressor effortlessly is to use the i-Command® Touch Control on your FS-Curtis Nx Series of Air Compressors. This advanced compressor controller can be set to turn off your air compressor at the end of a shift or workday automatically. Another energy-saving option i-Command® Touch Control includes is it allows the system to reduce the pressure during non-production hours. Let’s say you operate several CNC machines, which need to be kept at 80 psi in order to maintain the tool settings. Your i-Command ® Touch Control can be set to reduce the system pressure down to 80 psi range during your off shifts. This reduces expenses on electric costs because for every 2 psi drop in your system pressure, you reduce your electric costs by 1%. So, that 20 psi reduction just reduced your electric usage by 10%.
- Fix Existing Leaks.
A quarter-inch air leak at 100 psi will cost you more than $2,500 a year. Pipe systems, hose connections, and filter/regulator housings older than five years can have leaks of up to 25 percent. Because it takes energy to generate compressed air, any air that leaks is money wasted. Approximately 80 percent of air leaks are not audible, so to minimize these problems, third-party help in detecting these leaks may be a necessity.
How can FS-Curtis features and benefits help with this step? Your local FS-Curtis distributor can help you with a leak survey using an ultra-sonic leak detector. They can find leaks in your system and pneumatic equipment without shutting down your production. The survey will provide you with a list of items needing attention and repair. Your utility may offer a cost-sharing program to help pay for the survey. You can have your maintenance team make the repairs or have your FS-Curtis distributor make the repairs.
- Prevent New Leaks.
As Benjamin Franklin said, “An ounce of prevention is worth a pound of cure.” So, be proactive and look inside your piping system. A clean, dry pipe indicates good quality air and no corrosion issues. Dust in the pipe is caused by particles in the compressed air. If compressed air is not filtered, or if the filter is clogged, pressure drops will occur and the risk of end product contamination will increase. Sludge in the pipe is bad news and must be fixed immediately. Dust and sludge in a compressed air piping system will cause corrosion very quickly and will greatly increase the number of leaks. Dried and filtered compressed air keeps piping clean.
Your distributor will often recommend installing a Flow Meter where your compressed air leaves the compressor room and flows to the “Demand Side” of your air system. Some Flow Meters can be tied into your building’s data logging equipment. If you don’t have a data logging system, a simple log sheet that your maintenance staff can use to write down the flow rate will work. If you start to see an increase in the flow numbers, it’s time to investigate. Did you add new equipment that takes more air? Did a process change? If nothing changed, its time to look for air leaks again!
- Reduce Pressure. Run at required pressures, not beyond.
A two psi reduction cuts energy consumption by one percent. Check the system pressure and resist the urge to turn up the pressure to compensate for leaks or drops in pressure due to piping problems or clogged filters. A central supply side controller can greatly reduce the operational pressure band and orchestrate air production much more efficiently and effectively.
Your FS-Curtis distributor is a good resource to help you. They can help you establish a pressure profile of your facility. Let them help you find what process or equipment is needing the highest pressure. Often we find air supply systems running at 15 to 50 psi higher than what is really needed. A simple DemandSmart® Flow Controller may help you manage your demand side pressure and flow. Not only will you reduce your energy bill, but your facility may have less wear on air tools and improve your product quality due to a constant air pressure in our plant. Have your FS-Curtis distributor include checking needed down-stream point of use filters for pressure drop and clogged filters. Sometimes folks crank up the pressure to get more pressure to the equipment, when a change in the filter element is really needed.
- Check Drains. Are your condensate drains stuck open?
Condensate drains on timers should be adjusted periodically to ensure they open as intended or aren't stuck open. Better yet, replace timer drains with zero-loss drains to stop wasting compressed air.
How can FS-Curtis features and benefits help with this step? First, when you purchase a new air compressor select an energy saving zero-loss drain. While the zero-loss drain may have a higher investment price, you will not be losing compressed air every time the timer opens the drain valve. The opening of the timer drain can cause the compressor to come on for a short period of time causing an unneeded motor start and extra wear on the air compressor. Always make sure your FS Curtis distributor is checking your auto drains for correct operation when they are doing your scheduled maintenance.
When specifying a compressed air system for optimum operation and energy efficiency, proper selection of the compressed air receiver tank(s) is one of the most critical decisions one can make. There are several different “rules of thumb” and formulas that will assist you, but finding straightforward guidance that says “use this size air receiver” is difficult if not non-existent.
Air receivers can be used in several different ways in a compressed air system:
- “Primary” receiver between the supply side (air compressor and ancillary equipment), and the demand side (your plant). Today’s air compressor controls (on/ off-line, modulation, and variable frequency) strive to maximize energy efficiency and smooth compressor operation by responding to demand side pressure changes sensed at the discharge of the package.
A properly sized air receiver acts as a “buffer” and minimizes the effect of dynamic demand side pressure changes, allowing the compressor controls to operate smoothly and consistently. The end result is less energy used, longer component life, and consistency in plant air pressure.
- “Secondary” receiver typically on the demand side, at the point of use to minimize the effect large intermittent air demands have on the overall compressed air system.
Sizing a PRIMARY receiver for general FIXED SPEED APPLICATIONS:
- The air compressor industry has widely accepted the general rule of thumb that a properly sized air receiver for a fixed speed compressor should be between 1-2 gallons per CFM output of the compressor.
Example: A 100 CFM fixed speed air compressor should have an air receiver between 100-200 gallons sitting next to it. Err on the high side if your budget permits.
Sizing a PRIMARY receiver for general VARIABLE SPEED APPLICATIONS:
- When considering air receiver sizing on a variable speed drive application, the general rule of thumb is between 2-4 gallons per CFM output of the compressor.
Example: a 100 CFM variable speed air compressor should have an air receiver between 200-400 gallons sitting next to it. Err on the high side if your budget permits.
Useful Air Receiver Sizing Formulas (Primary and Secondary):
Use this formula when you have an existing air receiver
and need to know how long you can draw CFM greater than the output of the air compressor, from the receiver, while still maintaining system pressure:
- T = R x P1 – P2 Qr – Qc 7
Use this formula to determine what receiver size to use to supply pressure for a given period of time, not allowing the system to drop below a minimum pressure. The demand of air is greater than the CFM output of the air compressor:
- R = 7 x (Qr – Qc) x T
P1 – P2
Use this formula to determine how long it will take to recharge an air receiver to P1, after demand goes back to being below CFM output of the air compressor:
- T = R x (P2 – P1)
Qr – Qc x 14.7
T = Time in minutes
R = Receiver in cubic feet Qr = CFM removed
Qc = Compressor output in CFM
P1 = Maximum air receiver pressure P2 = Minimum air receiver pressure
14.7 = Atmospheric pressure in PSI (sea level)
CUBIC FT to GALLON CONVERSION: 7.48 gallons in a cubic foot