End-of-Life Decisions for Rotary Screw Air Compressors
May 21, 2025Optimizing Rotary Screw Compressors for Seasonal Temperature Swings
Kaishan USA | May 28, 2025 | Uncategorized
To ensure continuous operation without downtime, industrial facilities should prepare their compressed air systems for temperature extremes.
Air compressors are uniquely tied to atmospheric conditions, perhaps more than most other industrial equipment.
In many ways, they are at the mercy of the TV weatherperson, mainly because the raw material they start with is ambient air. Wintry weather brings the risk of freezing lines, sluggish oil and water condensation, while summer brings heat that can damage equipment across your entire compressed air system.
The first thing you need to do is determine what air compressor temperature range you are dealing with year-round. Very few people in the U.S. have the extremes: tropical conditions, with annual lows never going below 50°F or arctic conditions with temperatures never going higher. In most cases, it’s between 10°F in winter lows and 95°F in summer highs.
As a result, most American companies cope with seasonal extremes, highs and lows. We’ll address the key concerns for both extremes, starting with the cold.
Dealing with Winter’s Icy Blasts
Rotary screw air compressors are more efficient in the cold. Because of the density of the air, it takes less energy to compress it, and bringing in cooling air helps offset some of the heat generated during compression.
But freezing weather—anything below 35°F-40°F—introduces serious concerns. Like most other mechanical devices, from computers to cars, air compressors experience adverse impacts when freezing temperatures arrive. Especially when parts of the compressor or compressed air system are exposed to the elements.
Specific concerns include:
- Oil viscosity. Oil gets thicker as it gets colder, creating more drag for the motor of an oil-lubricated rotary screw compressor. If not addressed, the current will increase, causing breakers to trip and shut off the power. And your compressed air supply.
- Seals and hoses. Rubber and other elastomer materials become harder and less flexible in the cold, increasing the risk of cracked hoses and leaking seals.
- Water condensation. As temperatures drop, the air’s ability to hold moisture declines, causing water to condense. In some places, especially condensate traps, it will freeze and create blockages, making your compressed air system less efficient. Dryers work harder to remove water from the air, and, ultimately, some will get through, damaging work product and end-use equipment and corroding pipes or exposed metal. Plus, if you have a desiccant dryer, you may have to replace the beads.
- Water freezing. Water reaches its peak density at 39.2°F—meaning it expands as it gets warmer than 39.2°. It also expands as it cools. All that expansion and contraction can wreak havoc, breaking water hoses and fittings. That’s a special problem for water-cooled machines.
Pipes freeze, ice blocks drains and seals become more brittle in colder temperatures.
Fortunately, the industry has developed approaches to keep your compressed air system operating despite the cold weather, holding energy and repair costs in check.
Low-Ambient Temperature Compressors
Kaishan has developed a true cold-weather air package for its special low-ambient temperature compressors. These units include:
- An electrical enclosure heater to keep the electrical elements warm enough to prevent condensation, corrosion, stuck contents and other damage.
- A sump heater to stop compressor oil from thickening in the separator tank and enable easier starting. It also reduces energy consumption when the compressor is running.
- Trace heating/insulation to prevent condensation and freezing along pipes or other surfaces.
Trace heating involves attaching an electrical heating element to winterize pipes or other surfaces to keep them from freezing.
- Independently controlled thermostats to manage the compressor’s immediate environment more effectively.
All those elements are managed and powered through the control system, so no extra work or cost is required.
While most of our competitors rely on copper, brass or steel (which corrodes over time), Kaishan compressors have more robust stainless-steel pipes and fittings. In addition, all our liquid-cooled compressors use glycol, rather than water, as the cooling medium, to reduce the risk of freezing.
We use stainless-steel pipes and fittings in all our rotary screw air compressors.
For more on dealing with cold temperatures, with special emphasis on ways to maintain or upgrade your system to prevent winter problems, read our blog post, “Using an Air Compressor in Cold Weather.”
Compressors also have significant challenges in the summer weather, because they generate so much heat.
Dealing with the Heat
Elevated outdoor temperatures can negatively impact air compressor efficiency. If it’s already hot outside, that heat must be removed, or your compressed air system efficiency will suffer.
How hot is too hot?
The ambient air that enters your system, presumably at 70°F, will reach 175°F-200°F in an oil-lubricated screw compressor before it is cooled, according to Air Compressor Guide. You’ll need cooling and drying equipment to condition that air down to a more manageable level. However, it will still be 10°-20°F higher than your incoming air.
As a result, if it’s hot outside and your intake air is at 110°F, you will struggle to get the compressed air you send downstream below 120°-130°F.
And that will kill a lot of equipment throughout your compressed air system. For more on the negative impact of heat, read our blog post, “The Impact of Temperature on Air Compressor Efficiency.”
Kaishan Advantages
Most competitors only rate their compressors at 104°F (40°C), then want to charge more for units that can handle higher temperatures. Unfortunately, we see many industrial applications that run much hotter, in the range of 115°F (46.1°C), so our oil-flooded units are rated for a running temperature of 122°F (50°C).
In addition, we use Class F insulation on the main motor, rated to withstand a maximum temperature of 155°C, to ensure the insulation will withstand the heat of a typical application. You’ll also want to consider the heat impact on auxiliary motors running fans.
The key thing to remember is that if you go too far beyond the rating, you’ll risk burning out the motor. The rule of thumb is that every 10°C you operate a motor above the insulation rate cuts the insulation’s service life in half, according to Machine Design magazine.
The Special Heating Challenge for Oil-Free Compressors
Cooling the airend is even more of a challenge with an oil-free compressor, because they do not use oil as a cooling agent (although gear oil floods the jackets in the airend to help cool the discharge air and keep the housing temperatures lower).
Heat creates special challenges for the oil-free rotary screw air compressors serving the food and beverage industry.
As a result, an oil-free machine runs much hotter than its oil-lubricated cousin—the ambient air that enters your system at 70°F will reach 350°F in an oil-free rotary screw air compressor. That presents quite a cooling challenge.
Kaishan equips its KROF two-stage oil-free rotary screw air compressor with oversized coolers and high-temperature, stainless-steel pre-coolers. As a result, the KROF is built to withstand temperatures of 115°F (46.1°C), the highest temperature range we customarily find in U.S. facilities.
We equip our KROF two-stage oil-free rotary screw air compressor with oversized coolers to remove heat and it is built to withstand temperatures of 115°F (46.1°C).
Variable-Speed Drives
The sensitive electronics of variable-speed drives make them particularly vulnerable to high temperatures. There are three options:
- Do nothing. Some customers do nothing and take their chances. That can be expensive.
- Pay for an upgrade. Others pay more and get an upgraded VSD that can withstand heat. That is expensive as well.
- Go remote. We prefer a remote VSD, which involves locating your VSD device in a climate-controlled area, such as a server room or data center, or somewhere cooler than a typical factory floor. Typically, we say the maximum distance is 40 feet, but longer distances are possible with appropriate filters. See your distributor for details.
Another VSD-related issue is that VSDs gain heat in turn-down mode. If you are considering an oil-free compressor equipped with a VSD, you should discuss that heat gain with your equipment manufacturer.
One last consideration when dealing with heat is to review your entire compressed air system. It’s imperative that you have enough storage.
The Compressed Air & Gas Institute (CAGI) recommends up to 10 gallons per CFM of system capacity. Most facilities have a combination of wet and dry storage, with a third of storage capacity as wet storage and two-thirds as dry.
To handle any temperature extremes, it’s imperative that you have enough compressed air storage.
For more on storage, see our blog post, “A Quick Guide to Accurately Size Air Compressor Tanks.”
Maintenance
No matter the weather conditions, it’s always smart to adopt good maintenance practices to keep your system functioning properly. We encourage all our customers to develop several different levels of maintenance:
- Regular cleaning and inspection of filters and drain traps, removing any obstructions and replacing clogged filters.
- Oil sampling, ensuring your oil has the remaining life to keep the compressor properly lubricated, thus reducing operating temperature.
- Preventive maintenance, doing routine procedures like oil changes and filter replacements regularly.
- Predictive maintenance, closely monitoring data from sensors located throughout your compressed air system and taking action to deal with problems before they become serious.
After all, good maintenance is preferable to unplanned shutdowns, which can result in lost production time and ruined processes and materials.
For more information on preventive and predictive maintenance, see our blog post, “The Differences Between Air Compressor Preventive Maintenance and Predictive Maintenance. And Why You Should Care.”
Beating the Heat Is a Team Effort
The larger (and more mission-critical) your compressed air system, the more you will benefit from having a compressed air consultant’s advice and assistance. From sizing ductwork to helping you set up good maintenance practices, a professional’s advice can help you deal with heat problems that could otherwise damage your equipment or cause unplanned downtime.
We have developed close partnerships with a nationwide network of independent distributors. They have the experience and skills to offer expert advice and help you prepare for the temperature swings you can expect in your region.
Beyond dealing with seasonal variation, they can help you maintain and optimize your system, enhancing air compressor performance and compressed air system efficiency.
We’ve chosen to work with these independent, local businesses because we know there’s no better way to ensure you have the expert guidance, faster response times and personalized support you deserve. For them, it’s not just about selling compressors. It’s about building relationships that ensure you get the right system, reliable service and quick access to parts when you need them most.
The goal? Helping you maximize efficiency and minimize downtime. When you buy through Kaishan, you're getting more than a product—you're getting a local partner who cares about your business and wants to see you succeed.
Key Takeaways
- Air compressors are uniquely tied to atmospheric conditions, perhaps more than most other industrial equipment.
- The first thing you need to do is determine what air compressor temperature range you are dealing with year-round.
- Rotary screw air compressors are more efficient in the cold. But cold weather introduces some serious concerns regarding oil thickness, cracked seals and water condensation and freezing.
- Kaishan has developed a true cold-weather air package for its special low-ambient temperature compressors.
- Elevated outdoor temperatures can hurt air compressor efficiency. Heat has to be removed, or your compressed air system efficiency will suffer.
- Our oil-flooded compressors are rated for a running temperature of 122°F (50°C), significantly higher than competitors’ products.
- We build our KROF two-stage oil-free rotary screw air compressor to withstand temperatures of 115°F (46.1°C), significantly higher than other oil-free units.
Let Us Help
Dealing with changing seasons is critical to the operation of your rotary screw air compressor, your compressed air system and all the processes that rely on that system. If you need help getting ready for changing weather, get in touch with the experts at Kaishan. Contact us today.
Listen to the Podcast Version
Addressing Compressed Air Leaks and Maintenance Strategies
Welcome to the Big Dog podcast! It's finally here, our very first one. Thanks for joining us.That's right, Jason!
Right here, industrial air meets unfiltered, no-nonsense conversation. Powered by Kaishan USA, this podcast dives deep into the world of rotary screw compressed air systems—breaking down the tech, trends and the real challenges faced by end users who keep the industry moving.
And, even if we are AI-generated, Lisa, these straight-talking discussions are based on human-driven content—giving you the knowledge you need without the fluff.
Alright, so let's get started. Here's a big one facing the industry today: addressing leaks.
So, here's what most facilities don’t realize, Lisa—compressed air systems lose somewhere between 30 to 50% of their volume to leaks. In poorly maintained systems, that number can creep up to 80%. Let that sink in.
Wait, 80%? That’s massive. Why do you think something that glaring keeps getting overlooked?
Honestly, I think it’s one of those "out of sight, out of mind" things. Leaks are easy to ignore because you don’t always hear them. Only about 20% make that hissing sound everyone thinks of. The rest are stealth leaks—silent but deadly for your energy bill.
And those silent ones—are they harder to find, or can facilities just not be bothered?
They’re tougher to pinpoint, yeah. In fact, handheld detectors don’t cut it most of the time. You need ultrasonic leak detectors, which screen out all the background noise from other equipment. That’s the kind of tech most in-house teams just don’t have access to.
That makes sense. But even if you’ve got the right tools, leaks feel like only part of the problem. Isn’t maintenance—or the lack of it—the bigger issue here?
You’re absolutely right. A solid maintenance program is critical, and not just for leaks. The numbers show that proactive maintenance can slash costs by up to 70%. That’s huge, but—and this is the kicker—a lot of facilities don’t bother because they think their teams can "handle it."
Which, clearly, they can’t.
Not when it comes to advanced tech or consistent upkeep. Look, if you're serious about performance and efficiency, you’ve gotta team up with professionals. They can help you set up the right program, catch issues early, and keep your compressors running smoothly.
And what’s the alternative? Just burning through energy and money?
Pretty much. Facilities that let this slide are throwing money away while making excuses. It’s short-sighted and costly in the long run.
So, build a maintenance program, invest in leak detection tech, and stop wasting resources. Got it. But here’s a thought: if proactive maintenance is this effective, why do so many industries drag their feet?
Good question. I think part of it is just cultural inertia. A lot of industries operate on a "fix it when it’s broken" mentality. They don’t realize the savings they’re leaving on the table by not staying ahead of problems.
Which is wild, because the data’s all there, right?
Exactly. The evidence is overwhelming, but change takes time. It’s why we need more awareness around how much leaks and poor maintenance really cost.
Selecting the Optimal Compressor for Enhanced Efficiency
Speaking of efficiency, let’s talk about one of the biggest decisions facilities make—choosing the right compressor. Take two-stage rotary screw compressors, for instance. They can deliver up to 15 to 20% more air flow compared to single-stage ones of the same horsepower. That’s a lot of bang for your energy buck.Hold on—so just switching to a two-stage setup gives you that big of a boost in efficiency? What’s the catch?
The catch is upfront cost. Two-stage compressors are pricier out of the gate, but the payback can happen within a couple of years just from energy savings alone. Plus, they’re gentler on the equipment since the workload gets split between stages, which reduces wear and tear.
Makes sense. And I’m guessing that’s good for sustainability too—less waste at the end of its life, right?
Exactly. Split workloads mean cooler operating temperatures and longer component life. So not only are they efficient, they're also better long-term investments environmentally.
Okay, but let’s back up for a second. Even if someone’s sold on a two-stage compressor, isn't accurate sizing just as important? Like, what happens if you overdo it on the size?
Oversizing is a huge problem—no pun intended. People think getting a bigger compressor "just in case" gives them flexibility, but it’s the opposite. Oversized units end up cycling on and off too much.
Which burns more energy, right?
Exactly. Plus, all that cycling leads to overheating, oil carryover, and, frankly, the compressor wearing out faster. Oversizing is like buying sneakers three sizes too big—you’ll regret it in no time.
So how do you get it right? Is it just about matching horsepower to demand?
Demand, yes, but you’ve gotta consider peak loads and application specifics. And let’s not forget about mixed-use scenarios. That’s where an air audit can save your bacon, but we’ll get into that later. For now, the big takeaway is: think precision, not overkill.
Got it. Now, what about variable-speed drive compressors? Those seem like an easy solution for adapting to fluctuating demand.
They can be, but only in the right conditions. VSDs adjust motor speeds to match demand, saving energy by avoiding full-speed operations when they’re not needed. Facilities with variable loads see the biggest benefits.
But there’s a downside, isn’t there?
There is. At low usage, VSDs can run too cold and build up moisture, which eventually damages the internals. And at high usage levels, they’re actually less efficient than fixed-speed models because of drive losses.
So they’re not the one-size-fits-all solution some people think?
Exactly. They’re great tools, but only if they're matched to the right situation. Otherwise, you’re looking at diminishing returns—or worse, damaging your investment.
Implementing an Effective Compressed Air Design System
Now that we’ve talked about choosing the right compressors—whether it’s two-stage, fixed-speed, or variable-speed—and ensuring they’re sized correctly, let’s shift gears to system setup. If reliability is your goal, your configuration matters. Here’s a starting point: a three-compressor setup—base, trim, and backup. No shortcuts.Let me guess, each one plays a specific role, right?
Exactly. The base load compressor carries your minimum demand. Trim units handle the spikes, and a backup stands by for emergencies. This setup doesn’t just keep things running; it slashes downtime and makes maintenance way smoother. You’re basically building in resilience from the ground up.
But what about the costs? I mean, adding extra compressors—it’s gotta be an investment, right?
It is, but the numbers make sense long-term. Remember, electricity eats up 76% of a compressor’s total cost of ownership. It’s not the unit itself that’s pricey—it’s the daily grind of keeping it powered. Having a smart configuration minimizes inefficiencies, which means real savings.
Okay, but let’s say someone’s stuck with old equipment that’s guzzling energy. How much are we talking in terms of savings if they upgrade?
Depends on how outdated the system is, but upgrades often pay for themselves through energy efficiency alone. Think about it—just swapping older compressors for modern ones can reduce electricity use by tens of thousands annually. Plus, manufacturers are constantly improving their tech. Sitting on aging equipment is like burning cash.
Yeah, and it’s not great for sustainability either, is it?
Not even close. Old compressors are less efficient and more prone to breakdowns, which increases waste. Plus, facilities without reliable backups end up renting diesel units, and let me tell you—diesels are environmental nightmares.
Right, because they’re not just pricey—they’re dirty, too. But why would anyone still rely on them if we’re this far along in trying to go green?
Because planning ahead takes effort. Backup compressors eliminate the need for diesels, but that requires a deliberate investment. A lot of plants don’t think about it until it’s too late—then they’re stuck scraping for quick fixes like diesel rentals, which cost way more to operate and maintain.
And the air quality from diesels—it’s worse too, right?
Way worse. Most don’t include aftercoolers, so they send wet air into the system, which puts extra strain on your dryers. It’s messy, inefficient, and anything but sustainable.
Alright, so we’re back to the same message—get your system planned right upfront so you’re not scrambling later.
Exactly. A well-designed system with a backup plan costs less in the long run, keeps you efficient, and makes life easier for everyone on the floor. It’s a win on all fronts.
And if you’re not sure where to start, I’m betting an air audit can fill in the gaps?
Absolutely. Professionals can pinpoint inefficiencies and find opportunities for savings you’d never notice on your own. It’s like getting a roadmap to a better, more sustainable operation. Which, honestly, is what this all comes down to—being proactive and intentional. Don’t wait for the next failure to make changes. Plan smart, upgrade wisely, and keep your systems humming. Exactly. And on that note, we’re done for today. Great conversation as always. Yeah, this was a good one. Alright, everyone, take care and see you next time!
