Mich. community pool increases IAQ, energy efficiency with retrofit
Photo by Bryon Center Aquatics
The Byron Center H.S. Community Pool might now rank as one of the nation's most sustainable natatoriums in post-retrofit energy and refrigerant reductions.
Most people in this Michigan town of 6,000 residents knew a commercial dehumidifier retrofit closed the 80,000-square-foot pool area for an expedited two weeks, but most aren't aware that the equipment rigging and switch-out with a 50-ton, 40,000-CFM dehumidifier replacement took just one day.
More than 60 trades people representing seven contractors were onsite that long day removing the existing dehumidifier, disconnecting building controls, cutting open the roof/support joists, removing an exhaust fan, rerouting electric, piping and ductwork for access, hoisting the new dehumidifier in two sections through the roof and into the mechanical room, reconnecting the support joists, repairing the metal roof deck’s 12 x 12-foot access hole, restoring the building controls, plus myriad other support tasks.
The retrofit's uniqueness involved more than just a quick turnaround. The facility's improved indoor air quality (IAQ), energy efficiency and indoor air comfort for swimmers and 400 spectators is credited to innovative planning by the design team.
The retrofit’s energy-efficient equipment choice, an NP-050 Protocol indoor pool dehumidifier manufactured by Seresco USA, Decatur, Ga., helped reap a $2,000 rebate from local utility, DTE Energy of Detroit reduced the facility's dependency on global warming potential (GWP) refrigerants and provided unprecedented operational energy savings.
Mark Cooper, project manager for Hurst Mechanical, said the dehumidifier costs were offset with a short 2.5-year payback due to its energy savings and the elimination of an estimated $20,000 in annual maintenance costs spent on the previous dehumidifier, which required periodic refrigerant leak repairs, one coil replacement, fan belt semi-weekly tightening/checking or quarterly replacements, and daily manual defrosting of the seized outdoor air damper during winter months.
Equally important to the operational cost savings is the facility's newfound indoor air comfort, which is now maintained at 45 to 55 percent relative humidity (RH) set points, and space and water temperature differential of two degrees with a very strict ±1 degree tolerance.
Besides precise set points, the dehumidifier also features free pool water heating from compressor waste heat recovery. It also recovers heat from the exhaust air to preheat 65 degrees or cooler outdoor air (3,500-CFM and 6,500-CFM in normal and event modes, respectively) before it's mixed with re-circulated air. A proprietary modulating reheat strategy flat-lines temperature and humidity swings, which in turn reduces compressor operation and wear-and-tear. The new unit's direct drive fans save 15 percent versus the previous belt-driven fans while also eliminating the labor/material costs of the old unit’s weekly broken fan belt replacements.
James Lehman, lead maintenance for Byron Center Public Schools, estimates that optimum efficiencies provided by the new dehumidifier will be maintained by the onboard CommandCenter and web-based software program that reports more than 60 operating parameters to his smart phone via dozens of factory-installed transducers. Smartphone alarm notifications are received within minutes if and when an inefficiency or system problem occurs. Officials can interact with unit functions via smartphone. Previously, an energy-intensive inefficiency experienced by the old dehumidifier could go unnoticed for months until discovered by service contractors during semi-annual service calls.
When documented after a full year of operation, the impact of the dehumidifier retrofit will add significantly to a $260,000 per year energy savings that the school district is already saving as a result of a 2014 energy retrofit that included LED-lighting and boiler replacements with two gas-fired pulse combustion boilers.
The dehumidifier retrofit also reduced the facility’s dependence on refrigerants, because the new dehumidifier uses 75 percent less refrigerant than conventional dehumidifiers.
Once the retrofit’s energy savings pays back the dehumidifier’s cost in 2.5 years, the facility is expected to save hundreds of thousands of dollars over the next 20 years in combined maintenance costs and energy savings.
Topics: Automation and Controls, Building Owners and Managers, Construction Firms, Energy Saving Products, Great Commercial Buildings, Healthy & Comfortable Buildings, HVAC - Heating & Cooling & Ventilation, Indoor Air Quality (IAQ), Interiors, Renovation / Restoration / Remodeling, Sports and Recreation, Sustainable Communities, Technology, Urban Planning and Design, Ventilation