A Variable Speed Drive compressor sounds like a smart idea, but is it really?
Let’s address the 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.
St Louis, MO, May 4, 2016– FS-Curtis/Curtis-Toledo, Inc., a leading manufacturer of reciprocating and rotary air compressors since 1854 has announced that their Nx Series of Rotary Air Compressors has been awarded the prestigious Plant Engineering Product of the Year GOLD Award.
The Nx series rotary-screw air compressor features the iCommand-Touch controller—an intelligent technology that features touchscreen capabilities with bright, full-color graphics. At a glance, users can track pressure, temperature, and usage to easily diagnose and optimize their facility’s air system. The controller graphs information and trends that can be downloaded to an SD card, for troubleshooting and quality control measures. Customers have provided praise regarding the innovative Nx series intelligent package design, which easily allows simple maintenance tasks. The unique design of the motor and fan, coupled with airflow baffling and superior sound insulation, ensures extremely quiet operation. So quiet, the unit can be installed where you need it the most.
“Trusted and dependable reaches a whole new level with our Nx series rotary screw air compressors. The overwhelmingly positive response from customers highlights the quality of the air compressor, which is further reflected in the Nx being selected as the Gold Winner from Plant Engineering,” said Matt Smith, National Sales Director, FS-Curtis. “The entire FS-Curtis team continues to be focused on providing customers with trusted and dependable compressed air solutions that exceed their expectations.”
Plant Engineering's Product of the Year program is a premier award for new products in the manufacturing industry. The annual reader-choice program provides Plant Engineering's audience with information about the top new products in their fields.
About FS-Curtis/CURTIS-TOLEDO, Inc.
Since 1854, FS-Curtis/CURTIS-TOLEDO, Inc. has been designing and manufacturing solutions for industry. The FS-Curtis Air Compressors brand continues to be the symbol of quality and excellence in the design and manufacture of air compressors. Dedicated to customers and loyal distributors, our brand names are synonymous with Legendary Reliability since 1854. FS-Curtis/Curtis-Toledo, Inc. is proud to be ISO 9001:2008 and ISO 14001:2004 certified.
If you would like more information about this product, please visit www.fscurtis.com or contact Natalie Fontana at 314.383.1300 or email at Info@FSCURTIS.com.