 |
|
| | | | | | | | | | |
 |
| |
|
|
|
 |
|
|
|
|
 |
Storing Energy Kinetically By Mark McGough Imaging equipment and data processing systems have advanced exponentially over the years. However, the archaic battery technology used with uninterruptible power supply (UPS) systems has proven itself costly, hazardous and of limited reliability in safeguarding that equipment from power disturbances. Furthermore, those hefty containers of lead and sulfuric acid take up a lot of space, require plenty of care and feeding, need frequent replacement and too often simply do not do the job when needed. That is why hospitals around the nation are having their batteries hauled away in favor of a more reliable, compact and economical alternative: flywheel energy storage systems. Flywheels store energy kinetically rather than chemically. This means time, temperature and usage — each of which degrades batteries — do not impact flywheels. Instead of replacing batteries every two or three years, flywheels spin for decades. A Perfect Solution The latest models, using magnetically levitated carbon fiber cylinders, use less energy and half the space of a comparable five-minute VRLA battery set. Minor hardware maintenance intervals occur only once every six years. That is why facilities such as Sparrow Hospital in Lansing , Mich. , have tried them and then ordered more. Last year, the 500-plus-bed hospital ordered six carbon-fiber flywheel systems to use with a 1000-kVA UPS protecting six labs for state-of-the-art cardiac and neurological catheterization procedures. Not long thereafter, they ordered a flywheel for a 130-kVA UPS protecting an information technology (IT) facility. Last July, another half dozen were ordered for another 1000-kVA UPS, and plans are in place to purchase two more to protect computer tomography (CT) equipment. “Batteries are the biggest point of failure in any UPS system,” says Jon Harris, supervisor of Sparrow Hospital 's electrical services. “We insisted on having the best backup equipment available, and that's why we chose Pentadyne-made flywheels as a part of our power protection system.” At Scripps Green Hospital near San Diego , Calif. , Alan Beyea, manager of engineering services, had been suffering the vagaries of lead-acid batteries for years. Many of the “10-year” UPS batteries serving the catheterization labs were failing in less than a year. This was a costly proposition that was going to get even worse with the addition of new catheterization facilities. The hospital would have to spend more than $70,000 to expand a room to house a new UPS and battery banks with twice the capacity. Fortunately, Beyea learned about flywheels just in time. “We just can't take any risks,” says Beyea. “A few months later, we had a flywheel-based 500-kVA system taking up less room than our previous 250-kVA UPS with batteries. That's significant.” A week after installation, the flywheel's activity log revealed why cath labs chew through batteries so quickly: The flywheels had discharged more than 350 times! That is because imaging equipment power inrush needs are very brief, but very high, making it impossible for the UPS's rectifier to keep up. All those short discharges were causing electrochemical havoc in the lead-acid batteries. “For patient care such as cardiac catheterization, this is a perfect solution: a small footprint, no battery maintenance and a lot of cost savings,” Beyea explains. “The financial equation was clear. With virtually no maintenance, it makes total economic sense. We've had them online for a couple years now, and they're working just fine.” Like a number of other healthcare facilities, Meriter Hospital in Madison , Wis. , gave flywheels a spin by ordering two to mate with a pair of 150-kVA UPSs protecting their IT facilities. A year later, three more were serving UPSs on their cath labs. “These clean energy storage systems are the superior product to accomplish the high level of power stability our facilities require,” says Meriter's biomedical engineering director, James Alt, who is comforted by the fact that the hospital's flywheel systems carry a nonprorated standard warranty of five years. Back at Sparrow Hospital , Harris adds, “Patients first, that's what we are all about here. With cardiac and neurological catheterization, there's no room for a power glitch. That's certainly how everyone would want it if they were on the table. And that's what our flywheel-based power systems are delivering.” |
|
|
 |
|
|
 |
|
