11 minute read
HVAC System Redirects Convent Resources
by IdeaSoil
The 100-yr.-old Convent of St. Dominic, Blauvelt, NY, was heated with a steam system and cooled with window units. The 100,000-sq.-ft. facility is now heated and cooled with 14 VRF condensers mounted on a small roof between the convent’s main building and the chapel.
cern for a number of years. The congregation knew that maintaining and fueling the existing heating and cooling systems were draining funds that could and should be applied elsewhere.
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The Convent of St. Dominic is the headquarters for the Sisters’ housing, administrative offices, a convalescent wing, and a large chapel. The 100,000-sq.-ft., five-story brick building was heated with an archaic steam system. In addition to the operating expense, the lack of heating-system control was a problem, especially in the hospital and living quarters. Only 40% of the facility was air conditioned by window units.
“We needed to make a change,” said Sister Catherine Howard. “There was a lot of potential to better serve the community, increase comfort, and become better stewards of the planet.”
SEEKING IMPROVEMENT In early 2015, with a charge to make major building improvements, the convent’s director of property management, David Reeves, approached Steven Winter Associates Inc. (SWA). The building-performance consultants have offices in New York City, Washington, and Norwalk, CT.
Michael Flatley, senior engineer and director of commercial projects at SWA, completed the New York State Energy Research and Development Authority (NYSERDA) Flexible Technical Assistance Program (FlexTECH). FlexTech provides objective, site-specific technical assistance and analysis to inform the implementation of clean-energy technologies. This helped determine what kind of energy conservation measures could be taken to reduce energy bills and minimize the convent’s carbon footprint.
Flatley also referred Green Star Energy Solutions LLC, to complete the building improvements and HVAC retrofit at the convent. Green Star is a building-performance contractor based in Brookfield, CT. Their work, which is often in NYC, is aimed at providing “holistic efficiency.”
“We combine Fujitsu General Airstage VRF (variable refrigerant flow) heating and cooling technology with drastic building-envelope improvements,” said Joe Novella, Green Star’s founder. “Windows, doors, weatherization, and insulation are often an integral part of our turnkey solution. This allows us to increase building performance, comfort, and longevity while also lowering the upfront and operating costs of the new HVAC system.” Fujitsu General America Inc. is located in Fairfield, NJ.
“NYSERDA looks for 10 to 15% energy savings,” said Tom Esposito, director of business development at Green Star. “But we strive for 40 to 70%, and routinely achieve it.”
After lengthy discussions with Reeves and the Sisters’ leadership team, the project was broken into three phases: insulation, engineering and permitting, and installation.
SHELL IMPROVEMENTS Aside from the obvious shortfalls of an old steam system and irregular window AC units, Green Star’s assessment of the building made the need for envelope improvements painfully clear. Other than small amounts of fiberglass batt stuffed ineffectively around several skylights, there was no insulation in the entire facility.
During the summer of 2015, Green Star completely insulated the building. Nearly 1,200 bags of loose-fill insulation were blown into attic spaces and exterior wall cavities, and dense packed in other areas. Insulation board was installed wherever possible, window and skylight penetrations were sealed, and mineral wool was used to fill gaps of various sizes.
“Exterior walls were brought up to R-30 and the attics are now R-60,” said Esposito. “Immediately, the air conditioning units started cycling, instead of running non-stop all day. It was a nightand-day difference, especially in the building’s upper levels.”
When insulation work was nearing completion, Green Star entered the engineering and permitting phase. Novella and Esposito were busy determining how to avoid or navigate the challenges that would soon come with the installation of state-of the-art HVAC equipment in an occupied historical building. They learned that the building would require 120 total tons (1,440,000 Btus) of heating and cooling capacity.
“The convalescent floor and residence areas are always occupied,” said Novella. “The beautiful, sacred chapel is used daily. To avoid problems with the building’s molding, gold leaf, paintings, and stained glass, we had to be very specific about where and how the system’s evaporators would be installed.”
The outside of the massive brick building was no different. The large VRF condensing units had to be hidden from view.
Before the installation phase began, Valentine Electric, Blauvelt, NY, designed the service upgrade that would be needed when
the building was switched from natural gas-fired steam to an electrically driven heat-pump system.
FLEXIBILITY AND VARIETY A contract for the installation phase was signed in February of 2016 and work began immediately.
All 14 Fujitsu General Airstage VRF condensing units were installed on an access roof between the main building and the chapel. Because the small, fl at rooftop is sandwiched behind and between two taller portions of the convent, it’s diffi cult to spot from the ground.
The electric-service upgrade was also simplified because all of the outdoor units were concentrated in one, easily accessible area.
The system includes a variety of 8- and 10-ton condensing units, which are paired into seven refrigeration circuits between 16 and 20 ton each. Inside the building, 144 units serve spaces large and small.
Throughout the chapel, steam radiators were removed from the oak casework and replaced with 18,000-Btu slim-duct units. The vertically mounted evaporators are completely concealed and provide heating and cooling to the sacred space. Other smaller slim-duct units are installed in bedrooms and hallways.
Conference areas, offices, and bedrooms are served by wallhung units of various sizes. Ceiling units are also used in several hallways.
On the fourth floor—the only area with existing ductwork— high-static air handlers were used to replace the existing ducted air handlers.
Installing units in every area of a building whose nature is commercial, residential, institutional, and religious, was easier said than done. Much care was needed to minimize disturbance throughout the entire project.
LIVE, WORK, AND WORSHIP “The respect that Green Star had for us is absolutely second to none,” said Sister Bridget Mary Troy. They worked around us at all times and did nothing to mar this sacred space.” Green Star worked around worship services in the chapel. In the residences and the convalescent wing, work was isolated to very small areas to allow everyday life to continue as usual. Work areas were kept very small and isolated with dust-barrier systems. As rooms were completed, units were powered up to immediately provide conditioning.
“One advantage of VRF equipment is the ability to install and commission systems incrementally,” explained Novella. “Some of the units on the residential floor were up and running while we were still installing others right down the hall.”
Green Star estimates that the project will yield 60% savings, while also providing air conditioning to portions of the building that weren’t cooled before. “This project not only allows us to better serve our ministries, but also increase our sustainability,” explained Sister Howard. “By bringing cost-effective and conservation-minded equipment to our building, we’re keeping with Pope Francis’ call to care for the Earth and care for all that has been given to us.” CA
Left. Conference areas, offi ces, and bedrooms are served by wall-hung units of various sizes.
Above. Throughout the chapel, steam radiators were removed from the oak casework and replaced with 18,000-Btu vertically mounted slim-duct units that are completely concealed.
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Watch a video about the project. Download the Fujitsu Airstage VRF catalog.
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