In an area of the hospital where 20 induction coils are located off the chilled water main, considerable maintenance was required on a regular basis. The air and dirt problems required two men to vent, bleed and purge the coils for up to two weeks consuming some 160 man-hours. This task was done three times a year to keep the coils operating.
During a typical sales call made to the hospital by Roedel, D'Allesandro & Mason (RDM & Associates Inc., Brookfield, Wis.), Carsten Fehr, the hospital's Power Plant Manager, saw a working demonstration of the Spirovent[R] combination air eliminator and dirt separator. The Spirovent, manufactured by Spirotherm Inc. (Glendale Heights, Ill.), employs a patented coalescing and barrier medium that scrubs the air and dirt from the system fluid allowing it to break free of the flow path. The air is released through a patented air release mechanism while the dirt falls to the bottom and collects in the dirt chamber where it can be blown down through a manual or automated blow down valve.
"Since the installation of the Spirovent we have not had to visit the coils at all," commented Fehr. To be sure, he has sent his men to spot-check the coils, only to have them return a couple of hours later finding no problems. The savings in man-hours alone translate to thousands of dollars!
The success of that installation led Fehr to insist that the new 250,000 square foot Northwest addition to the hospital include a Spirovent as well. He took his performance and maintenance data to the engineering team, convincing them to add a new 10-inch high velocity combination Spirovent to the project to address both the air and the dirt problems in the hospital's chilled water system.
Since starting up the system, Fehr has made several observations. "We used to add about 80 gallons of chemicals to prevent corrosion, and this season we have added only 12 since the original 20 gallons we used to get the system ready. Four main air handlers in the North Wing have not had to be cleaned or purged at all like they used to, and we have not had to flush anything in the other existing wings. The system pumps (equipped with variable frequency drives) used to run at 90 percent during the hot summer days and with a few of those days already behind us, they ran at about 70 percent and achieved the same efficiencies."
Fehr says that the Spirovent and some piping modifications have provided for this energy savings. He is a firm believer in the Spirovent and its unique features and benefits. When asked recently how he felt about the newly installed Spirovents, Fehr stated, "It's almost a start-up and forget-about-it set-up." Other hot-water heating and chilled water systems in the hospital may benefit as well when they are expanded or upgraded in the future.