Dehumidifier helps NYC school gets an A+ in environmental sustainability
February 1, 2008
Since environmentalism and sustainability are important parts of its curriculum, New York City’s private Ethical Culture Fieldston School (ECFS) practiced what it has preached when it built its new $75 million campus expansion.
Green ideas such as roofs with vegetation that are accessible to classes, waterless urinals, cisterns that capture rainwater for irrigation and maintenance, low-e glass glazing to reduce energy consumption, plus many recycled construction materials were used for the 47,000-sq-ft middle school, 38,000-sq-ft gym, 14,000-sq-ft swimming pool, and another 34,000 sq ft of renovation. The green focus could lead to a LEED® Silver certification the school has applied for, according to New York-based Levien & Co., the school’s construction representative.
Architect Cooper Robertson & Partners, construction manager Tishman Construction, and many of the contractors were chosen for the project because of prior experience with green building. While there are many types of conservation in the project, one of the major contributions to energy saving and heat recovery is the HVAC equipment.
Ambrosino, DePinto & Schmieder, Consulting Engineers (ADS), which specified the equipment, is an engineering firm specializing in green design and is a USGBC member with several LEED Accredited Professionals on staff.
Sacrificing Short Term Cost For Long Term SavingsOne energy-recycling example comes from the swimming pool’s comprehensive HVAC system, a DRY-O-TRON® model RS-162 manufactured by Dectron Inc. The 22,000-cfm dehumidifier not only keeps the 7,200-sq-ft swimming and 115-spectator spaces in a constant 50% rh, but it also recovers energy to provide free pool water heating for the school. If 100% pool water heating can’t be accomplished on extremely cold winter days, the dehumidifier has an on-board 540,000-Btu high-efficiency backup boiler, according to Robert Senia, president of HVAC manufacturer’s representative SRS Enterprises.
While some schools attempt to save construction costs with a basic makeup air and exhaust system, ECFS officials opted for a commercial dehumidification system designed expressly for indoor pools, involving higher upfront equipment costs but significantly lower long-term operating costs. “Once we explained the IAQ, energy saving, and short payback benefits of a state-of-the-art mechanical dehumidifier, other methods were never considered during the planning stages,” said Michael Ambrosino, principal, ADS.
The dehumidifier also uses another energy recovery method, Smart Saver, which pre-heats the unit’s 6,000-cfm outside air minimum requirement with hot exhaust air. Smart Saver is estimated to save the school $5,600 annually, based on natural gas prices of $1/therm.
A Pool-Length PlenumADS’s attention to sustainability didn’t restrict the architect’s aesthetics, which includes a high 20-ft ceiling to give the pool a feeling of spaciousness. The airflow design within the space still provides indoor air comfort regardless of the high ceiling. From the rooftop dehumidifier, supply air is brought in high on the natatorium’s wall into a plenum that spans the entire width of the pool. Aesthetically, the plenum is recessed behind the grandstands and only the six spiral metal duct runs emerge visibly into the space along the ceiling.
Other HVAC equipment on the project also recovers heat. Installed by ASM Mechanical Systems, 100% outdoor air systems totaling 20,000-cfm for the new project’s middle school area and gymnasium utilize heat pipes to recover energy from the exhaust systems that save both heating and cooling energy. Other equipment on the project includes an Andover Controls BAS, which will soon be retrofitted to also encompass the campus’ older buildings.
The ECFS is just another example of the emerging trend of schools functioning as environmental role models for their young impressionable school body. “Sustainability is becoming a resonant topic for many private schools that are seeking to expand and improve facilities,” according to Myra McGovern, spokesperson for the National Association of Independent Schools. “At the intersection of these two trends, you see a huge growth in the number of green schools being built,” she said. ES