A Kentucky Regional Medical Center
Retrofit Team
Lamps Installer: Medical Center facilities staff
Distributor: Thermal Equipment Sales, Louisville, Ky.
Materials
The RLM Xtreme fixtureless UV-C lamp system delivers high-output ultraviolet energy to irradiate coils and eliminate mold, bacteria and microbes in demanding, high-volume HVAC systems.
High-output RLM Xtreme lamps are single-ended, which facilitates a simple, but sturdy, mounting system and selection of a single-size lamp for all fixtures. This reduces the number of spares needed on hand and enables quantity-purchasing discounts during annual replacements.
The configuration installed in the hospital cafeteria’s air-handling unit consisted of four T5 (5/8-inch diameter), 61-inch-long UV-C lamps; a LampHolder that allows the lamp to be affixed in any position inside the air handler; and a power supply with a powder-coated, heavy-gauge galvanized steel and NEMA-2 rated housing. EncapsuLamp (FEP lamp coating) technology protects the system and airstream from glass and mercury residues should an accidental lamp break occur.
The UV lamps were installed on the downstream, air-exiting side of the coil, where they are most productive killing mold and bacteria and degrading all other organic materials. The UV-C wavelength removes this organic growth rather quickly, often in less than one month—a process that doesn’t produce any residual matter. The destroyed organic material is removed through normal condensate production until the coil is completely clean.
A properly sized and installed set of lamps will noticeably clean a coil in about 30 days with continued improvements up to one year later on severely clogged coils. The UV-C fixtures can be installed in about two hours. For this medical center, the UV-C installation represented about 10 percent of the cost of a new, replacement coil.
RLM Xtreme Lamps Manufacturer: UV Resources
The Retrofit
Engineers at this 359-bed health-care facility struggled to keep the hospital’s cafeteria cool amid the Blue Grass State’s humid climate. Condensate in the air-handling unit serving the food-service area was leaving a residue in the coil, a buildup that reduced airflow through the unit from the 14,000 CFM design parameter to around 10,000 CFM—nearly 30 percent less than what was originally specified. That, of course, meant the air handler wasn’t able to help keep the café and kitchen cool during peak demand, especially during standard meal times in July and August, when occupancy and thermal loads were at their highest.
In an attempt to boost cooling capacity, the hospital’s maintenance staff tried to increase the volume of airflow over the coil by performing up to three mechanical coil cleanings per year at roughly $300 per treatment. According to the engineer, the cafeteria AHU was the worst performer among the medical center’s roughly 30 air handlers, and he was considering replacing it—a task that would cost more than $20,000 and require the unit to be shut down for two to three days.
Sales Engineer Charles Haskins, with Thermal Equipment Sales, suggested installing UV-C lamps in the cafeteria air handler. If performance didn’t improve in six weeks, the hospital wouldn’t pay a penny. Having not tried this technology, hospital representatives had some skepticism regarding the UV-C energy’s ability to improve airflow and heat-exchange efficiency.
Although UV-C successfully has been used in health-care and institutional applications for more than three decades, many facility managers remain skeptical. As air-conditioning equipment ages, its ability to maintain adequate space temperatures and humidity levels decline. Most often, the culprit is reduced coil heat-transfer effectiveness, or the ability of an AHU’s cooling coils to remove heat from the air. UV-C systems remove organic growth on the outer and inner surfaces of the coil, thereby restoring the coil’s heat-transfer efficiency to “as-built” specifications.
In the end, an independent project audit documented a 35 percent increase in airflow, or an additional 3,700 CFM, as well as the ability to achieve the hospital’s cooling set points in the cafeteria.
The facility engineer was impressed with the results. “After a mere 90 days, airflow is back to design specs and we are able to maintain the desired temperature set points in the kitchen and cafeteria,” he says. “The AHU motor is drawing less amps, saving the hospital energy. Based on this successful demonstration, we’ve decided to incorporate these performance-enhancing UV-C fixtures in more of the hospital’s AHUs.”
According to the facility, the team plans retrofits for the air handlers serving the operating rooms, patient rooms and radiology department—a total of four additional units.
PHOTO: UV Resources