The original dehumidifier’s maintenance was surpassing $1,000 annually, mostly from small refrigerant leak repairs. A future catastrophic leak event of losing the entire 60-pound R-22 refrigerant charge could have potentially cost the facility more than $10,000 in refrigerant replacement and repair labor costs. More recently, the facility also faced replacing the perpetually leaking remote condenser component of the rooftop split-system at an estimated cost of $10,000.

Acting on the advice from its preferred HVAC service contractor, Red Bird Mechanical in Neptune, NJ, the 33,000-sq-ft facility chose new equipment with energy-saving heat recovery and enhanced IAQ.

“The pool odors we sometimes noticed are no longer a factor, and the pool area’s air comfort is significantly improved,” said Kathy Guibord, one of the senior directors at the Atlantic Club.

IAQ and air comfort have improved because of Red Bird’s reconfiguration of the natatorium’s 6,900-cfm ventilation ductwork and installation of a new 14-ton, NE-Series heat-recovery, split-system rooftop dehumidifier and condenser from Seresco. The indoor pool environment is now maintained at a 50% rh and an energy-efficient two-degree differential of 82°F and 80°F between space and water temperatures, respectively. Humidity and space/pool water temperature set points are maintained at a very strict ±1 degree tolerance, which results in a comfortable environment for members.

 The retrofit’s fast payback derives from today’s heat recovery technology, according to Ed Sneed, sales engineer with Stillwell-Hansen Inc., an Edison, NJ-based HVAC manufacturer’s representative, who contributed to the retrofit’s engineering. Unlike the older technology, the NE-Series recovers heat from the exhaust air to efficiently preheat the outdoor air, which amounts to an energy savings of tens of thousands of dollars annually. Its design also uses direct-drive fans, which are 15% more efficient than the replacement units’ outdated fan-belt driven technology.

Red Bird Mechanical also improved the ventilation system by relocating the natatorium’s return ductwork inlet down to deck level from its former ceiling position. The return grille now draws air from the deck area instead of inefficiently drawing air from recently introduced supply air. The lower positioning helps draw dry, conditioned supply air toward pool occupants for air comfort and prevents air stratification.

Replacement planning by Red Bird Mechanical President Frank Chinnici saved nearly $10,000 for the facility. Rather than replace the original unit’s roof curb, Chinnici ordered a custom-designed curb adaptor configured to the new dehumidifier’s ductwork configuration, which was vastly different than its predecessor. This circumvented the cost of roofing in a new curb, eliminated reconfiguring the existing downflow ductwork to fit the new dehumidifier, and minimized natatorium downtime.

Earlier in the dehumidifier’s lifecycle, Red Bird Mechanical had already replaced the pool space’s two corroded in-duct electric heaters with more efficient in-duct anti-corrosion coated hot water coils custom-manufactured by MultiTherm LLC. The heating coil retrofit also included a 12-V modulating valve by Honeywell that steadily ramps up and eliminates overheating the pool space on start-up. 

The dehumidifier also provides 200-Mbh capacity of heat recovery to efficiently heat the pool space. When the dehumidifier can’t reach set point level, the facility’s Carrier BAS triggers the three-way modulating valve to send hot water to the pool area’s in-duct heating coil.

The dehumidifier has an onboard CommandCenter microprocessor that reports over 60 operational parameters from dozens of factory-installed transducers to WebSentry, a proprietary Web browser-based software program that sends real-time data and alarms to Chinnici’s smart phone and factory servers for historical recording. Thus, any malfunction or operational inefficiency alarm is reported the day it occurs.

WebSentry’s historical data recording already helped Chinnici solve a perplexing intermittent space overheating alarm. Typically, heating coils are factory installed inside the dehumidifier and a strategically-positioned supply air sensor monitors temperature. WebSentry’s historical recording of the intermittent event suggested that repositioning the sensor downstream could better monitor temperature and prevent overheating.

Now with virtually no maintenance costs and thousands of dollars in annual energy savings, the natatorium retrofit payback is expected in just a few years.