Solar power rises high
The world’s most environmentally responsible high-rise office building is being built in midtown Manhattan in New York City.
The $1 billion project is being co-developed by the Bank of America and The Durst Organization and is scheduled to open in 2008.
The Bank of America Tower will serve as the headquarters for Bank of America’s operations in New York City, and house its global corporate and investment banking, wealth and investment management and consumer and commercial banking businesses.
The 51-storey, 288m (945ft)-tall tower will focus on water and energy efficiency, and indoor environmental quality. The project aims to halve water and energy consumption, and use 50% recycled materials in the building construction.
“I think there is a certain amount of public resentment concerning the amount of natural resources that commercial office buildings blindly consume,” says Jody Durst, co-president of The Durst Organization, which has a reputation for developing environmentally responsible commercial properties.
The tower is the first high-rise to strive for the US Green Building Council’s Leadership in Energy & Environmental Design (LEED®) Platinum rating. LEED is a rating system that defines the green credentials of a building, and Platinum is the highest rating that can be achieved.
“Many LEED buildings are in remote areas, so it’s always more interesting and challenging when there is a project in a major city precint,” says communications manager at the US Green Building Council, Taryn Holowka.
“City locations are more difficult as there is no control over the building site. For example, it might not have the East West orientation that will be cooler in summer and warmer in winter. There are LEED credits awarded to projects near public transportation, but in the city you can’t always choose (your position), and there’s a limited area to work in.”
Reducing water consumption
The tower will save millions of gallons of water annually through a grey water system to capture and re-use all rain and a portion of the building’s wastewater, while planted roofs will reduce the urban heat island effect.
The average New York City rainfall is around 1200mm (47in) per year, and the total storage capacity of the building’s rainwater and grey water tanks is 261KL (69,000 gallons).
“We’re capturing all the rainwater on the 30,000ft2 roof (2787m2), and will pipe it to a series of cascading tanks (starting from) the 50th floor,” says Bob Benazzi, plumbing engineer and partner in JB&B consulting engineers. “In this manner both water and energy savings are realized. Energy is saved since the captured storm water is diverted to flush valves on the water closets utilizing gravity only.’
“We’re very excited about the creativity that JB&B has committed to the project,” says Mr Durst. “We see water particularly as the next precious reserve in the United States, and anything that can be done to reduce consumption is noteworthy and newsworthy.”
Mr Benazzi says the water goes from a 7432m2 (80,000 ft2) eighth floor podium roof to a basement storage tank. “From the basement, water is pumped to the water closets in the podium and the cooling tower; this is how we offload the storm water.
“Storm water drains in New York flow to combined (sanitary and storm) sewers which tend to overflow when there’s heavy rainfall. By capturing the storm water from the site, the load on the combined sewer is substantially reduced, lessening the impact to the combined municipal sewer and thus lessening the chance of sanitary overflow to the river.”
The eighth-floor roof podium will also have a green roof. “When the water goes to that roof, it will water the plants, and we’ll capture water through the soil and pipe it to the water tank,” says Mr Benazzi. “Irrigation will use the grey water system.”
Waste water is captured directly from the lavatories in the core toilet rooms, as well as the cooling condensate from the air-conditioning in summer, and the steam condensate from the heaters in winter. It goes to the storm water collection and is filtered and delivered into the cooling tower and flush fixtures.
“We filter all recycled and rain water, and turn over the tank every two hours,” says Mr Benazzi.
“There will be a screen filtration of 10 microns (which filters out particles up to 10 thousandths of a millimetre, or a few millionths of an inch). Filtered water is then passed through ultraviolet to provide for bacteria kill.”
Waterless urinals and low-flow fixtures also help to decrease the use of water. “Waterless urinals reduce the water flow rate by one gallon per day per person.”
Mr Benazzi says recycled and treated black water won’t be used on the site, as it is not economically feasible; that is, there is no return on the money used on the energy to maintain it. There is also no need for using black water as there will be enough water from recycling grey water and capturing rainwater.
“If we had a black water plant, we would have the same problem as New York City: if it rained heavily the overflow would be flooding the storm water drains.”
Any concern about piping non-potable as well as potable water has been addressed. “We are making sure there won’t be any cross connections as a result of plumbers mixing up the pipes,” says Mr Benazzi. “We’re only delivering grey water to core toilets in the main building, and other tenants, including Bank of America, will only be piped with potable water. No waste water is piped into the recycle tank, and there is nothing connected to the grey water piping.”
Taking advantage of heat energy from the cogeneration plant, a thermal storage system will produce ice in the evenings, which will reduce the building’s peak demand loads on the city’s electrical grid.
The main financial benefit is the savings on mains water usage. Mr Benazzi predicts total annual water consumption slightly in excess of 98 million L, (26 million gallons) per year. “Overall, there will be 43% savings in water consumption,” says Mr Benazzi.
The following table outlines the approximate financial savings predicted from using less water.
Mr Durst points out that there are financial benefits to organizations having an environmentally responsible reputation. “We’re finding corporate tenants increasingly want to project to worldwide customers their commitment to environmental responsibility.
“By providing real estate products that demonstrate and project concern for the fragile nature of our environment, corporations can align themselves with this philosophy, which not only allows The Durst Organization to adhere to its principles, but it also distinguishes Durst products in the marketplace.”
Financial benefits are also gained from the well being of an organization’s employees, says Mr Durst. “About 80% of costs in a corporate environment relate to personnel. Making the user environment healthier and more pleasant to work in, reductions in job lethargy, less absenteeism, and an improved sense of well-being, culminating in increased productivity for both the employee and the corporation. Delivering more fresh air at a more stringently filtered level, as well as providing more natural light, are two such elements which have a profound effect upon work productivity.”
There are LEED projects worldwide, says Ms Holowka. “There are four projects certified in India, one in Sri Lanka and a number in Canada. There are other Green Building Councils across the world under the worldwide Green Building Council, which is headquartered in Sydney, Australia.”