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MIAMI - The Marian Center provides educational, residential, clinical, vocational, and recreational services to more than 150 students and adults ranging in age from birth to middle adulthood. Operated in seven buildings, the campus officially opened in 1964, but the central a/c system at the center’s 10,000-square-foot school building was overdue for replacement. Its age made the unit unreliable and it would often stop working when Florida’s heat was at its worst.
“We knew that the old system was on its last leg,” said Thomas Horan, executive director of the Marian Center. “The conditions were tough on the students, and staff, and sadly, we didn’t have an emergency fund for anything of this magnitude financially.”
EQUIPMENT INTERVENTIONCharles Del Vecchio, owner and CEO of Tropic Supply in Miami, a wholesaler of HVAC and mechanical systems, had been covering the cost of repairing the old existing chiller system, as his grandson was attending the school. The building’s existing system, based on a 40-ton, R-22 reciprocating chiller, cooling tower, and dozens of fan-coil units, had been deteriorating further each year. The key dilemma was the discovery that the chilled water piping, buried under the school, had ruptured.
“Besides the mechanical issues, the Sisters and the students were having an awful time competing with the noise of the fan coil units,” said Sister Lidia Valli, school principal.
“We couldn’t decide what was worse, the hissing, whining, gurgling noises from the old room units, or the heat and humidity we and the students had to endure,” said Sister Carla Balentini, facility manager.
With all this in mind, Del Vecchio called Horan and offered to cover the cost of new equipment for the school. Considering the many problems with the old system, Del Vecchio and school administrators decided that the best solution would be to abandon the ruptured lines and to remove the chiller, cooling tower, and fan coil units.
REPLACEMENT CHOICES“We were drawn to the energy efficiency of new, smaller R-410A systems,” said Bob Garrison, president of Miami-based Garrison Mechanical, the firm chosen to replace the ailing equipment. “A big advantage to the installation of multiple, smaller systems would be the ability to easily select which areas of the school to cool.”
When it was apparent that the use of many smaller units would offer greater efficiency for this installation, a plan was drafted to install 23 separate Fujitsu mini-split heat pumps. The Del Vecchio family, with the help of engineers at Formica & Associates, drew up plans for installation of ductless split systems that they would donate.
The list of equipment included four ASU9RQ single zone wall mounted heat pump indoor units; four AOU9RQ matching outdoor units; 16 ASU24RLQ single zone wall mounted heat pump indoor units and 16 AOU24RLQ matching outdoor units; three ASU18RULX single zone, universal mounted (ceiling or low on floor) heat pumps; and three AOU18RLX matching outdoor units.
INSTALLATION LOGISTICSThe school building is a single-story rectangle with a central hall and six large classrooms, all of which also have a smaller observation room behind a two-way mirror. There are several bathrooms, a library, and administrative offices. According to Del Vecchio, key jobsite challenges were the many sliding glass walls and the school’s poured concrete roof.
“There’s no attic space up there to run refrigerant lines, to conceal ducts, or to hide air handlers,” said Garrison. “It was an open-and-shut case for mini-splits.”
Garrison Mechanical work crews began the job with initial preparations. “Once the grounds were cleared, we framed-out and poured concrete slabs for all of the condensing units,” explained Garrison. “Then we removed and scrapped all of the old equipment.”
The installation of new equipment began in the summer of 2009. According to Garrison, the job moved briskly in phases with two, two-man crews. “We began at one end of the building and completely installed and wired each new system, placing them online and ready for service,” said Garrison. “This took less than a month, start to finish.”
During that time, Garrison’s crew enacted an earlier plan to make the indoor units fit into spaces where the old equipment had been. Wood enclosures, stained to match other furnishings, were installed to conceal and offer easy access to fresh air filtration, a Miami code requirement. The evaporator units were then attached to the outer face of these enclosures for an aesthetic touch greatly appreciated by the school.
According to Garrison, the facility received a total of 39.5 tons of heat pump comfort control with air filtration and humidity control, and with a jump from 7 or 8 SEER to 16 to 18 SEER. The school now enjoys a marked improvement to operational efficiency.
“The difference is amazing,” said Horan. “We had become so conditioned to the noise of the old units, and their inability to keep us comfortable. Now, just entering the rooms, experiencing the comfort and not hearing all that rattle is a thank God moment every day.”
For more information, visit www.mariancenterschool.org.
Publication date: 04/26/2010