Author: Cameron Ballentine
A Variable Speed Drive compressor sounds like a smart idea, but is it really?
Earlier we posted a blog on why rotary machines are often not ideal applications in auto care shops –Now let’s address another rotary compressor question that auto care facilities ask us on a regular basis: Should I spend the extra money to put an energy-saving Variable Speed Drive (aka: Variable Frequency Drive) rotary screw compressor in my facility? The short answer to this question is: probably not.
The folks asking this question have heard that VSD/VFD machines may cost more up front but that they cost less to run and thus pay for themselves in the long run. In addition, many utility companies offer rebates for VSD/VFD machines that can help offset the larger up-front cost. Just like everyone else, automotive care facilities want to save money and energy, so this supposed value proposition sounds attractive. Right?
So why then is VSD/VFD probably not a good idea for most automotive care facilities? The short answer is that most automotive care facilities typically have severe peaks and valleys in their compressed air usage due to the intermittent use of tools and equipment in the shop. This in itself does not rule out VSD/VFD. In fact, VSD/VFD is ideal for customers whose demand fluctuates, provided that it does not fluctuate too much. The problem with auto care facilities is that their valleys are too deep. Too much downtime. The rule of thumb is that when the valleys are 30% or less of the peaks, the compressor will have to shut down, essentially forcing it to run as a start/stop machine. There are several issues with running a VSD/VFD machine in this type of application:
- More expensive – First of all, the customer is paying a 30% or more premium for a VSD/VFD machine to run just like a cheaper start/stop fixed speed machine. Perhaps the more important comparison is that the customer would be paying a whopping 70% premium compared to a fully-loaded UltraPack recip, which is probably the best application in most auto care shops.
- Phantom Energy Savings – VSD/VFD machines are ideal for loads somewhere between 30 and 80 percent of full load. There are little to no energy savings otherwise. Even though very short payback periods are often cited, these are for machines in ideal scenarios with exactly the right load profile. Auto care facilities very seldom have an appropriate load profile. If one isn’t going to get the benefit of the VSD/VFD, why pay extra for it, and risk some of the potential headaches outlined below?
- Increased Maintenance -
o VSD/VFD’s require minimal incremental maintenance on the drive compared to standard fixed speed machines. These increased costs should be considered in any decision to go with a variable speed machine.
o VSD/VFD’s require a cleaner environment for the sensitive electronics of the drive. This can lead to increased maintenance costs and possibly drive replacement, which is very expensive. If the machine is going to be placed in a shop with dust and other contaminants floating in the air, then the cost of protecting the drive from these contaminants, or paying extra for maintenance and/or replacement, must be considered.
The bottom line is that most auto care applications are not ideal for VSD/VFD machines. The severe valleys in demand profiles mean there probably won’t be energy savings to offset the increased acquisition and maintenance/replacement costs. In addition, most shops are too dirty to install a VSD/VFD without increased risk and cost.
On our path to becoming the most trusted and dependable compressed air equipment provider in Norther America, we at FS-Curtis have just taken another major step forward.
FS-Curtis is proud to announce the newest addition of our Nx Rotary Screw Air Compressor Series. The Nx18-37 kW (25-50 hp), is now available in Variable Speed Drive! The NxV 18-37kW variable speed drive compressors are built on the same reliable platform as the fixed speed product introduced earlier this year. There are, however, some notable differences. These compressors are controlled by a variable speed drive to match energy consumption to demand, they utilize a robust direct drive arrangement, and the iCommand Touch controller is now standard on the 18-37 kW Variable Speed Drive units at no additional charge. With the standard iCommand-Touch, a full-color screen displays graphs which capture and track factual, real-time air usage by the hour, day, week and month. Historical data can be retrieved at any time with a touch of the screen. The data trending keeps your finger on the pulse of your entire compressed air system.
Introducing this new addition to the FS-Curtis Rotary Screw lineup continues to show that through the dependability of our people and our quality-focused manufacturing, FS-Curtis will continue to be a trusted name serving even more markets through our ever-growing global presence.
In order to help us grow in our mission, we welcome your feedback to help us improve and exceed your expectation.
The FS-Curtis Sales and Marketing Teams
Here’s What You Need to Know
If you’ve been in an auto body shop recently (which is unfortunate because it probably means you’ve had fender bender) or a small manufacturing operation, you may have heard the not-so-inconspicuous hum and rattle of an air compressor. More than likely it was a two-stage compressor. Why not a single-stage? Generally, single-stage units are for less demanding operations like home garages or construction job sites where the distinctive pop, pop, pop sound of nail guns pierce the air like firecrackers on the 4th of July. Nail guns or the occasional use of a rachet gun only require single-stage compressors.
So, why would you need a two-stage air compressor? There are three main reasons:
- Redundancy – If one pump/motor fails or needs service or repair, the other pump/motor can continue to operate, avoiding downtime. Important for any business. Your air flow may be cut in half, but it's better than shutting down your business while the compressor is service.
- Electrical Limitations – What if you absolutely need a 10-15HP compressor but three-phase electrical service is either not available or too expensive run? A duplex compressor with single-phase pump/motors would be your solution.
- Varying Air Usage – If you’re air needs, CFM, fluctuates throughout the work day, where one minute you’re using a small hand tool and the next a sand blaster, a two-stage compressor is perfect to help regulate air flow. When air consumption needs are low, only one pump/motor will operate on your two-stage compressor, but both pumps kick in when demand increases. Smart little boogers, aren't they.
If you’re in the market for a new two-stage compressor, here’s what to look for before you commit.
Definition: One HP is the force needed to lift 550 lbs. one foot in one second.
With all the hubbub made over HP, the CFM (cubic feet per minute) your compressor can generate is actually a more critical factor. But, it’s true that generally speaking, the more HP you have, the more CFM it can produce, so there is a direct correlation that can’t be overlooked. That said, it’s more prudent to shop by CFM, not HP.
CFM (cubic feet per minute)
Every air tool in your shop has a specific CFM requirement—the higher the CFM, the more air volume the tool uses. Keep in mind that if you’re a furniture shop then your sanders will require more air than nail guns.
Take an inventory of CFM requirements for each tool, and the number of everyday tools, and then calculate your necessary CFM, regardless of whether they will all be operating at the same time or not.
Single-phase? Three-phase? What’s the diff?
Generally speaking, single-phase electrical is found in residential settings. Three-phase in commercial buildings, manufacturing operations, etc. So, obviously your first consideration whether to choose a single-phase or three-phase compressor is based on where you will be using it.
Sidenote: Three-phase electricity is considered to be more efficient and therefore could result in less wear and tear on your compressor’s motor.
Keep in mind that electrical codes, voltage and phase vary widely geographically so be sure to check your local building codes and with an electrician before laying out that credit card.
So, now how big of a tank do you need for your compressor? How many gallons?
With two-stage compressors tank sizes range from 60 – 200 gallons. The size of your tank should be basedon how often the compressor will be in use.
This should give you enough to go when choosing your next, or first, two-stage compressor and enough ammunition to ask intelligent questions.
If you should have questions regarding purchasing a two-stage compressor, call our customer service department and we will be happy to assist you: 800-925-5431. Or, visit us online at: us.fscurtis.com
Click on the icons below to download product information about FS-Curtis reciprocating compressors.
How One Food Processing Plant Saved $150.000 Annually
According to the Advanced Manufacturing Office in the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE), American industries spend $5 billion annually on compressed air. In the case of food plants, costs are not documented, leaving compressed air systems principal candidates for waste and abuse.
Follow these 5 steps to save your food processing plant enough money by the end of the year that you'll be glad you took five minutes to read this article.
- Examine and analyze your compressed air system
Note all the uses of compressed air in the plant and all the air compressors available by enlisting the help of engineers and technicians, and then:
Conduct a self-audit of your compressed air system
There are 10 most important targets to evaluate in a compressed air system audit:
- Estimate actions to repair deficienciesCorrect the problems that are the least expensive to repair. Using a Pareto diagram can be useful to help separate the “critical few” deficiencies from the “trivial many” possibilities that are available. For example, the Pareto diagram is shown in figure 1, where the solution for the problem is listed on the X-axis (Improvement). The Y-axis (Savings) shows the estimated savings (less costs) that would result from repairing the problem. Projects shown in the tallest bars should be choosen for implementation.
Figure 1: Pareto diagram helps to select the most effective actions.
- Implement the best solutionsAfter identifying the best alternatives in step three, it is time to execute. Beware that some processors postpone taking action because of time constrains, but it may be worthy to hire extra help to carry out recommended solutions right away. Every action should be measurable in terms of cost and savings.
- Track resultsAll solutions that were implemented should be reviewed regularly to ensure that the results are as expected, or to find out if something has changed or requires additional attention. Once recommnded changes are made, then the five-step process can be repeated to double check yourself.
If you think your company could benefit from having a compressed air system audit performed, viist this link to find a distributor in your area to inquire about scheduling an audit. You can also call our toll free number to talk with a customer service rep about locating an FS-Curtis distributor in your area: 800-925-5431.
Click icons to download product literature for compressors used in the food processing industry.
Check out this article: Food industry factory saves $154.000 in annual energy costs, to see how one plant was able to save over $150.000 annually in energy costs.
Source: Oklahoma State University. Food technology fact sheet.
Question: Would you dump lawnmower oil into your car's engine? Probably not. Your neighbor's, maybe, but not your precious heap of a jalopy.
Same strategy holds true for your air compressor. Just like automobile oil, there are many different grades of air compressor oil to choose from, each designed to meet certain specifications.
Two main factors are involved in choosing the correct oil:
1) The type of compressor. Rotary screw or recip?
2) The environment your compressor operates in. Hot, humid temperatures? Cold? Dirty air? Clean, sterile environment?
Many compressors, many environments, many choices.
Solution? Of course there is. What's a riddle without an answer.
To help ease your pain when choosing oil for your compressor, FS-Curtis has introduced two new fluid lines: FSC-Max Fluid and Pro Fluid.
FSC-Max Fluid is our core fluid product line and comes with a bold new look. Designed to offer the highest protection for your FS-Curtis products and to operate at 100% efficiency in virtually all environments, FSC-Max will help run your unit efficiently and smoothly in various environments from food grade applications to large industrial.
How much faith do we have in the FSC-Max Fluid line? All FS-Curtis products are tested and shipped from our headquarters and plant in St. Louis, MO., using FSC-Max Fluid.
It's also the only lubricant product line that can validate FS-Curtis extended warranty programs.This is important in order to protect your investment and ensure its longevity.
Pro Fluid is a great new addition to our professional grade line of products and offers a full range of fluid choices for virtually all circumstances. It is also an ideal economical alternative for OEM replacement fluids, and a great choice when servicing industrial machinery.
For more information about which fluid is the best choice for you compressor, ask your FS-Curtis sales representative, call our service representatives at 314-383-1300 or visit our website at us.fscurtis.com