In July 2003, New Yorkers got their first look at a truly revolutionary building in their midst. The So-laire is a 27-story, 293-unit, glass-and-brick residential tower in Battery Park City, a planned residential and commercial neighborhood built on landfill bordering the west side of New York City's financial district and directly adjacent to the site of the former World Trade Center.
The Solaire has been environmentally engineered to consume 35% less energy, reduce peak demand for electricity by 65%, require 50% less potable water, provide healthier IAQ, and offer substantially more natural light than typical residential buildings. To reach these goals, many energy conserving technologies were incorporated, including the installation of an efficient gas-based chiller system and high-efficiency variable-speed pumps, motors, and fans. Multilevel humidification and ventilation systems supply filtered fresh air to each residential unit.
The Solaire is the first building designed in accordance with new environmental guidelines instituted in 2000 by the Battery Park City Authority (BPCA), the government entity that oversees the development of Battery Park City. It is also the first green (environmentally sustainable) residential high-rise building to be constructed in the U.S. By going green, The Solaire also qualified for the relatively new green building tax credit offered by the state of New York.
Another duly noted first for The Solaire is that it was the first new residential construction project to be completed in downtown Manhattan since 9/11.
Air Quality ConcernsAfter 9/11, air quality in the area of the former World Trade Center became a big concern, due to the significant quantities of smoke and dust released into the air following the destruction of the twin towers. Late into 2005, the EPA was still testing the air quality in lower Manhattan to see if any asbestos, man-made vitreous fiber (MMVF) or lead and polycyclic aromatic hydrocarbons (PAH) remained in the air following the collapse of World Trade Center buildings.
This is one of the reasons why many IAQ features were incorporated into the design of The Solaire. In addition, the developers of The Solaire, Albanese Organization and Northwestern Mutual Life Insurance Company, wanted a project that they could market as "America's first environmentally advanced residential tower."
The IAQ at The Solaire follows stringent standards, with fully filtered, humidified (or dehumidified), centrally conditioned air provided to all residential units and common spaces. All apartments have digitally programmable thermostats and operable windows, allowing occupants to choose between fresh and conditioned air.
The ventilation system provides 100% outside air with 85% efficient filtration at the central intake. Outside air is introduced into the units via ducts that are placed at a minimum of 25 ft away from any exhausts. All ducts and register locations in the building were kept closed during construction to prevent the infiltration of construction dust into the air-handling system. To further ensure high air quality, the system was operated for a period of time prior to occupancy to flush out any contaminants.
Individual humidifiers help maintain the building at approximately 35% rh, said Marvin Lewin, vice president of Cosentini Associates, New York. "We specified individual packaged electric units that produce steam at the AHUs, and we installed steam nozzles into the ductwork to spray the humidity into the system."
There is CO2 monitoring in some public areas, and a representative number of resi-dences contain continuous IAQ monitor sensors. These sensors were placed in several apartments at the top, middle, and bottom of the building, so air quality could be monitored throughout the structure. All the sensors are tied into an Andover building automation system, which is monitored by in-house engineers 24 hours a day, 7 days a week.
To make sure the air quality remains at the highest possible level, an air quality test is performed each year. In addition, positive air pressure is maintained within the building corridors, and the park-ing garage is equipped with CO2 monitors. A comprehensive commissioning plan is in place, in order to ensure that the building meets its intended design standards.
Other SystemsSeveral different heating and cooling options were considered for The Solaire, including electric chillers and a heat pump system. According to Lewin, though, "We found we achieved a much larger energy reduction from the New York state energy code at that time by going to gas-fired absorption units over electric chillers."
To that end, two McQuay gas-fired, double-effect, absorption chiller-heaters were installed, and a four-pipe system delivers chilled and hot water to fancoil units located in each apartment. VSDs were installed on the cooling tower fans, both chilled and hot water pumps, as well as premium efficiency motors.
Installing a gas-fired chiller made perfect sense, especially considering that during periods of peak demand, the New York City power grid sometimes does not have the necessary distribution system to accommodate demand. At these times, users often rely on supplemental power provided by highly polluting generators, but the gas-fired chiller at The Solaire reduces that potential need.
The domestic hot water system consists of high-efficiency condensing boilers, along with premium efficiency motors. Due to the corrosive nature of the exhaust in high-efficiency condensing-type boilers, a stainless steel exhaust pipe was also installed.
Given the green nature of The Solaire, it would seem only natural to install heat recovery ventilators, and indeed, the owners wanted to pursue this. However, due to zoning restrictions that limit the size of rooftop equipment, they were not able to have these incorporated into the design.
The Solaire also has 3,400 sq ft of photovoltaic panels, which generate 5% of the base building's overall energy requirements at peak performance. The panels were installed on the building's west façade on the canopy and clipped onto the mechanical bulkhead on the roof. Locations were chosen to balance efficiency with the associated costs of installation. Space has also been provided for the installation of fuel-cell technology, eliminating the need for costly building modifications when such technology is more mature and its use is more viable.
An on-site blackwater system at The Solaire recycles 100% of the building's wastewater. Water recaptured by the system is used to supply the cooling tower makeup and the building's water closets, and 5,000 gal/day are provided to the adjacent public park. Fifty percent less potable water is needed from the municipal water supply than would be used in a conventional apartment building, and no potable water is used outdoors. Low-flow appliances and fixtures are used, and the public restroom facilities use waterless urinals.
Stormwater runoff is collected in a storage tank in the building's basement. The system will capture approximately 170,000 gal/year, to be used for irrigation of the rooftop gardens. The system was designed to precisely accommodate the irrigation load for the site, allowing for a significant reduction of the capacity of the retention tank and utilizing 100% of the stormwater captured on the site.
Higher Costs Of Being GreenConstructing a green building often means more expense. In the case of The Solaire, initial expense was definitely a consideration, especially considering the cost of the building's HVAC system was $7 million. However, in addition to the bottom line, the owners analyzed the top line, said Lewin. "Building a green building means building a better building. This results in increased value, which justifies many of the incremental costs."
Lewin estimates it costs an additional 17% to 25% to construct a green building, noting that these costs are for the entire building and not just the mechanical systems. "Understand that for air quality purposes, the walls had to be caulked between apartments, so odors couldn't travel. We also had to seal the interior walls to make sure that we don't get infiltration from the exterior into the building. The BAS is much more sophisticated, and there are monitoring systems, alarms, and photovoltaics. These are some of the many things that wouldn't normally be in a residential building."
Cosentini Associates will have the opportunity to incorporate many more green - and air quality - technologies into the next residential high-rise project they're working on in Battery Park City. That's because the developer, The Albanese Organization, is always looking to go to the next level of improving IAQ, according to Edward Barbieri, P.E., senior vice president with Cosentini Associates. "We're looking at possibly including recirculating HEPA filtration units, bipolar ionization, and UV lights," he said.
Time will tell what will ultimately be included in the new building, but as for The Solaire, its ten-ants are very pleased with its energy efficiency and healthy IAQ.
Sidebar:The Solaire, located in Battery Park City, New York, incorporates two green roofs: an intensively planted 5,000-sq-ft terrace green roof on the 19th floor and a 4,800-sq-ft extensive green roof on the 28th floor. According to Green Roofs for Healthy Cities (www.greenroofs.org), which bestowed an Award of Excellence on The Solaire, these green roofs are an integral part of the sustainable, low-impact design objectives of the LEED® Gold-rated building.
Green Roof Uses Solaire Runoff
Both green roofs employ a layered system of an American Hydrotech membrane MM6125 EV-FR, a root barrier, 4 in. of Styrofoam insulation, a moisture retention mat, and a filter fabric. The lower, intensive green roof supports planters at varying heights from 6 to 18 in. that contain a growing medium called "So-Lite." In the planting beds, a layer of bark mulch is spread over the growing me-dium to reduce soil erosion due to wind.
The landscape architect, Balmori Associates, conducted specific research as to what plants would thrive on the roof top at this particular site in order to create a diverse palette that would require little maintenance. The terrace green roof was designed to respond to typical harsh rooftop conditions such as desiccating winds, urban pollution, and intense solar radiation.
Self-sustaining shrubs, perennials, and bamboo trees were chosen not only for their aesthetic appeal, but also for their ability to resist drought, strong winds, and to adapt to shallow soil depths. The dense strand of bamboo trees planted in the center provides a windscreen throughout the year and shades the green roof's paths and benches.
Balmori Associates collaborated with the architects to incorporate a hydrological system into the infrastructure of the building. The green roofs are expected to absorb nearly 70% of rainwater and fil-ter out heavy metals and pollutants from excess runoff. This cleaned runoff water is then collected in The Solaire's basement cistern along with the building's grey water and is later used to irrigate nearby parks. The green roof design is also integrated into The Solaire's mechanical equipment with the in-tention of unifying the garden and mechanical components.