High school swimming pool gets cost-saving HVAC dehumidifier retrofit
How do you save $400,000 in construction costs in a swimming pool retrofit of HVAC support equipment? Lincolnshire, Ill.-based Adlai E. Stevenson High School and School District 125 show the way.
The 3,950-student school’s huge 40,000-square-foot natatorium, one of only four 100-meter Olympic-sized pools in Illinois, was faced with replacing two aging HVAC dehumidifiers requiring tens of thousands of dollars annually in maintenance costs. The removal of the sizable 15 (L) by 9 (W) by 8 (H)-foot heat recovery dehumidifiers would require upwards of $400,000 in construction costs to tear open a wall or roof, according to Mark Michelini, assistant superintendent for business at School District 125.
Instead of complete removal, the school district gutted the existing units and kept their shells in place. Dehumidifier manufacturer, Seresco USA, Decatur, Ga., was commissioned to factory-build entirely new 64- and 40-ton dehumidifier components, coils, piping inlet/outlet receptacles and control packages that would fit inside the original manufacturer’s steel shell configurations.
The reconstruction of the units is expected to someday become a standard retrofit procedure as thousands of huge circa 1980s and 1990s natatorium mechanical room dehumidifier lifecycles end and need replacement. Dehumidifiers are typically very large and most mechanical room access doors weren’t designed to accommodate their removal and replacement units.
Factory engineers designed the entire configuration. They provided the installing contractor with 3-D, computer-modeled blueprints. That helped simplify on-site assembly and installation of the components into the old shells.
The new partially assembled internal component packages arrived as a compressor/refrigeration circuit skid. Separate fully dipped enamel corrosion-proof evaporator, reheat and hot water coils, command center/electrical control panels and dry coolers were included in the assembly. The design of the entire package helped to minimize onsite assembly.
Through the retrofit, the high school got greener dehumidifiers than the circa-1996 original units. Instead of a conventional 100-percent refrigerant dehumidifier, Stevenson now has Seresco’s NP-Series Protocol models. The Protocols together displace nearly 1,200 pounds of the original systems’ refrigerant with environmentally friendly glycol that’s PVC-piped to rooftop dry coolers 60 feet away for heat rejection. The project was completed September 2014 in time for the school year to start.