VFDs: Increasing power, conserving energy
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Increasing power, conserving energy

Understand how VFDs reduce energy consumption without sacrificing performance.


Many carwashes have seen business improve as the economy slowly recovers. However, things may never get back to “normal” or how they were before the recession. Washes and other businesses must learn how to adapt to a new customer base as well as new ways of operating, which can include discovering smart ways to cut back on costs.

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Fight rising costs

“Utility costs have been going up, and that’s not just electric but water and sewer, too,” says Kevin Detrick, president of Innovative Control Systems. He adds there are no indications utility costs will go down, and as carwashes trend toward using more horsepower in vacuums and larger blowers, variable frequency drives (VFDs) could be the answer. VFDs present the ability to save money by reducing energy consumption without sacrificing performance.

Carwash owners and operators can calculate their return on investment with VFDs by looking at energy costs. “We are doing two things,” states Detrick. “One, all the VFDs are eliminating in-rush, which equates to the demand portion of your energy bill. Two, we are reducing kilowatt usage by running motors and pumps at slower speeds.”


Reduce power throughout the wash

Carwashes can benefit from reducing energy costs from several common pieces of equipment. When deciding where to install the technology, owners should look at their specific needs.

VFDs can be used with a variety of components, including self-serve equipment. Gary Wirges, president of CustomKraft Industries Inc., notes VFD technology allows the delivery of “any product to the customer with a choice of pressure settings and with fewer components.”

Detrick shares that owners who experience problems cleaning wheels or issues with side blaster noise would want to target those areas. He recommends operators ask themselves if they want to improve performance, reduce costs or both.


“The bigger horsepower items like the vacuums and the blowers are typically where you are going to save the most money and get that higher return on investment,” explains Detrick. “A vacuum transducer will reduce motor speed and allow you to run the vacuum at an optimal level while consuming less energy.”

Vacuums and blowers are the most popular equipment to use with VFDs, notes Detrick. The components are also added to high-pressure pumps, hydraulics, boost pumps and reclaim pumps.

“When looking at your vacuums, you can enhance the customer experience by always offering the same amount of suction or lift,” says Detrick. “You want the optimal amount of lift at the vacuum nozzle, and you can generally get there at a lower RPM.”


Vacuum turbines speed up as more people use the vacuums, continues Detrick, which increases energy consumption. The VFD allows carwashes to regulate the energy used and provides customers with the optimal amount of suction.

“Blowers generally have the highest amount of horsepower in the carwash,” states Detrick. He explains VFDs are typically used to run blowers at three speeds. Blowers can idle between cars at half speed and close the blast gate — if present — to reduce usage.

Running blowers at full speed is not always ideal, either. “Instead of going to full dry, we’ve found that on some blowers it is better to run at 52 Hz, which equates to a 10- to 15-percent reduction in speed without impacting drying,” shares Detrick.


Blower operation can also differ according to the type of vehicle on which they are used. Speeds can be dropped down to 25 to 30 percent for pickup trucks and convertibles, says Detrick. This keeps water from blowing off trucks onto cars behind them, and it prevents damage to convertible tops.

High-pressure pumps can also be successfully run with VFDs. “Instead of unloading water and running a pump and motor flat-out all the time, with a VFD you can run that motor 20 percent slower by not unloading water, using a pressure transducer, and only running the motor and pump at the RPM necessary to get the pressure you want to achieve,” notes Detrick.


Operators can also target pressure on different sections of vehicles, continues Detrick. This provides a more personalized customer experience, as it results in a quieter ride through the tunnel, cleans wheels better and saves energy.

Controlling equipment with VFDs not only saves you money — it also adds to the customer’s wash experience. “Consistently delivering a superior service is key,” shares Detrick. “If your vacuum doesn’t work well or the customer’s home vacuum is going to work better, then it does not matter if you offer free vacuums at your wash.”

Maintain the equipment

VFDs are one of the more technical parts of carwash operation, and it’s important to ensure they run correctly to experience the benefits they offer. Wirges believes, “There should be one primary employee familiar with the manual and one trainee for backup.”


Detrick agrees one employee should be on-site, and he says another person with qualifications to work with high voltage should be able to come in when needed to service the drive.

VFD upkeep depends on the environment in which it is kept. If the components are in a sealed environment with air conditioning, explains Detrick, owners will not have to clean them out.

“Without air conditioning a lot of dust and dirt will get sucked into the VFDs from the fans,” he cautions. “The drive will overheat and fail.”

Wirges says depending on the cleanliness of the environment, operators may have to remove dust and grime monthly or annually. “Do not allow visible dust buildup on the air flow ports,” he notes.


Owners will also benefit from reduced maintenance with VFDs, Wirges continues. “The reliability of the overall pump station [has] fewer parts and [there is] less downtime of the carwash. No in-bay check valves are required and the system uses a single delivery line for low-, medium- and high-pressure delivery through the wand.”

Detrick also advises carwashes to install VFDs during construction as opposed to retrofitting later. Owners will spend less on installation if it is done initially, rather than having to rip out old equipment and replace it.

In short, many benefits exist for washes that incorporate VFDs into their operations. “There are also opportunities for power company rebates, where your power supplier will pay a portion of the cost to install a VFD panel to help reduce the demand for electric on their system,” concludes Detrick.

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