There is a host of reasons why you should invest in industrial air compressors that are energy-efficient.
If you purchase an industrial air compressor that reduces your energy usage, you’ll save money and reduce your environmental impact. And if you invest in the most up-to-date equipment, you’ll probably also reduce downtime, improve the health and safety of your working environment, get more life out of your equipment and meet—if not exceed—emissions standards.
You can even enhance the quality of the compressed air your industrial air compressor provides, an essential consideration for industries like automobile painting, food processing, semiconductor and electronics.
So, while the answer to the “why?” of energy-efficient investment is fairly obvious, the real question is “How?”
Five Ways to Save Energy with Your Industrial Air Compressor Investment
We offer five crucial energy-saving tips below. For other energy-saving tips that are environmentally friendly, see our recent blog post, “Plant Manager Essentials: Seven Steps for a Greener Production.”
1. Select the right compressor
Selecting the right compressor for your facility is a crucial step in optimizing your operation’s energy efficiency. We review the three most common types below.
Reciprocating Air Compressors
Often called piston compressors because of their construction, reciprocating compressors are efficient for small applications. They are rugged and durable, holding up well when properly sized. Unfortunately, they need to be oversized because they have a low duty cycle, needing time to cool off. They work best with intermittent or partial duty, typically at a 50% duty cycle or less. That’s 30 minutes in an hour. Run it longer, and you risk damaging your compressor and shortening its life. As a result, to properly size a recip, you need to consider a compressor with a larger horsepower rating.
Centrifugal Compressors
Extremely efficient, especially at high volumes, centrifugal compressors can produce a lot of air from a small footprint and are very durable. Unfortunately, they are usually large (thousands of HPs) and are extremely expensive. They have a limited pressure range, are less efficient when air demand is low and do not handle partial loads well. Plus, completing maintenance tasks requires a high level of expertise. As a result, lifecycle costs may be higher.
Rotary Screw Compressors
Rotary screw air compressors are the industrial air compressors of choice because of their many advantages, including the following:
- Efficiency. Rotary screw air compressors are based on a simple, time-tested design that enables impressive efficiency. They deliver a continuous flow of air, resulting in smoother operation and significantly reduced energy waste. They operate continuously, minimizing fluctuations and enhancing overall efficiency.
- Steady air flow. Rotary screw machines are known for producing steady streams of compressed air without the pulsations that sometimes occur with other types of compressors, especially reciprocating or piston compressors.
- Versatile. Rotary screw compressors work best with a 100% duty cycle—we recommend setting up your compressed air system so that they operate as close to full load as possible. In addition, they can handle variations in demand and temperature extremes.
- Less maintenance. Because they have fewer moving parts, rotary screw air compressors require less maintenance.
- Long-term reliability. Rotary screw machines are designed for long-term reliability, giving them a relatively low total cost of ownership.
- Footprint. Rotary screw air compressors are compact and occupy relatively little floor space.
- Quieter. Compared to other types of compressors (especially reciprocating machines), rotary screw air compressors make much less noise.
- Warranties. Rotary screw air compressors generally have better warranties than other types of air compressors because of their reliability, efficiency and long life. In fact, Kaishan’s KRSP and KRSP2 rotary screw compressors are backed by a lifetime warranty on the airend.
Which Industrial Air Compressor Is Best?
Generally, a centrifugal air compressor is most cost-effective for high-volume applications (above 2,500 CFM). A reciprocating compressor is the best choice for low-volume applications (less than 20 CFM). But screw compressors are the best for everything in between. For more on the subject, read our blog post, “Which Type of Air Compressor Is Best for Your Application?”
2. Use Flow Control
To be truly functional, a compressed air system needs flow control. Flow control helps you maintain air pressure throughout your plant at the lowest optimum level, reducing artificial demand and increasing energy efficiency. Pressure-flow control thus buffers the compressors from the ups and downs of system demands.
Flow controllers require minimal maintenance, backing up when the filter is clogged. All too often, workers bypass the device rather than changing the filter. And the facility loses the energy savings the flow control was providing.
3. Avoid Rapid Cycling
Atmospheric air enters a rotary screw air compressor through an intake air filter, which removes particles or moisture. An inlet valve controls how much air is drawn into the unit and ensures no foreign objects and contaminants enter the system.
The inlet valve is wide open when your compressor is loaded and closed when it is in the no-load state. Unfortunately, the transition between the two states is not as rapid as we might like. It takes several seconds for the internal pressure to be relieved.
As often happens, the compressor may switch back into the loaded state before the transition to the no-load state is complete. If that happens too frequently, it can lead to rapid cycling, which is highly inefficient, causing increased wear, reduced compressor lifespan and potential safety hazards from overheating.
To combat rapid cycling, we often propose modulation that adjusts the inlet valve to a partially open position. While modulation has traditionally been viewed as a waste of money and energy, the loss is insignificant compared to the negatives of rapid cycling. It’s not out of the question to see a compressor with a ten-year expected life cycle fail after just six months of rapid cycling.
Kaishan is one of the only compressor manufacturers incorporating modulation into our units. Many others do offer field retrofit kits. But we feel the adverse impacts of rapid cycling are so significant that we make modulation a part of our standard offering.
Variable speed drives are a more energy-efficient way to address this issue but cost more up front. Neither modulation nor VSDs take the place of appropriately sized compressors and storage tank, however. It’s the best practice to have both wet and dry storage to remove moisture and maintain stable header pressure for these fast events.
4. Right-Size Your System
The typical commercial or industrial operation adds capabilities all the time—an expansion to do painting, a room conversion to add a new specialty and some new air tools. It all adds up, requiring more flow or pressure than your current system can handle.
But sometimes, the opposite is true. Your compressor may have been sized with “room to grow” or purchased to handle end uses that have since been removed from the system. It may seem counterintuitive, but with rotary screw air compressors, “too much” is almost as bad as “not enough.”
Here’s why. Screw compressors are designed for a 100% duty cycle. Run them significantly less than that, and you’ll waste energy, reduce equipment lifetime and perform more maintenance. That’s why it’s so important to have your air compressors sized appropriately.
A good example: we had a customer in the defense industry with several large compressors, including two 300 HP compressors and a 400 HP unit with a variable speed drive (VSD). Because the application was oversized, the customer was having reliability issues.
We conducted an audit and recommended and installed a KRSP2-250 two-stage rotary screw air compressor with a VSD. As a result, the company has saved over $30,000 a year, with substantially reduced maintenance costs.
Because the second stage builds on the pressure created in the first, a two-stage compressor like the KRSP2 will generate more compressed air for less energy.
It will also generate less heat of compression, allowing it to maintain tighter tolerances, further increasing efficiency and reliability. Two-stage compressors also have more bearings, all under less stress, extending the overall life of the air compressor.
The bottom line? A two-stage air compressor like the KRSP2 will generate up to 15-20% more flow in the same size air compressor, decrease overall power costs and have a longer life with reduced downtime. That’s an energy-saving investment that will generally recoup the price difference quickly.
5. Stop Leaks
Compressed air systems lose between 30% and 50% of their volume to air compressor leaks, with poorly maintained systems running as high as 80%.
As a result, one of your first tasks is determining how many leaks you have. And estimating how much you can save by fixing them. (To find out how much you might save with an audit by an air compressor professional, see our blog post, “How an Air Compressor Audit Can Reduce Operating Costs.”)
Handheld leak detection devices have been available for some time and have been successful at helping companies locate the 80% of compressed air leaks that are not in the audible range.
But now there are newer, visual, acoustic imaging devices known as ultrasonic leak detection systems. They use multiple directional microphones to triangulate the position of a leak source, overlaying the leak’s ultrasonic “signal” on a video image of your plant.
For more information on fixing links, see our blog post, “How to Find and Stop Air Leaks.”
Local Help
Kaishan USA works with a nationwide network of independent distributors, who can provide on-site help and consultation as needed. These factory-trained air compression experts have an investment in their local communities and can service your air compressor system without a problem. And they have staff members skilled in using advanced technology like the ultrasonic leak detection devices mentioned above.
Key Takeaways
- Purchasing an industrial air compressor that reduces your energy usage will save money and reduce your environmental impact.
- It may also help you cut downtime, improve health and safety, lengthen equipment life, enhance air quality and comply with emissions standards.
- Selecting the right industrial air compressor for your facility is a crucial step in optimizing your operation’s energy efficiency.
- Flow control allows you to maintain air pressure throughout your plant at the lowest optimum level, cutting energy usage and cost.
- Rapid cycling decreases efficiency, increases wear and reduces compressor lifespan. It can lead to overheating.
- Compressed air systems lose between 30% and 50% of their volume to air compressor leaks.
Let Us Help
Making energy-conscious investments in your industrial air compressor is critical to the operation of your compressed air system and all the processes that rely on that system. If you need help deciding how to get the most benefit, get in touch with the experts at Kaishan. Contact us today.