4 Times Square

In stark contrast to Bedzed, Zion Visitor Centre and Hockerton Housing Project; 4 Times Square is a skyscraper which is 48 stories high and located in Manhattan, New York City. This building claims to incorporate one of the most environmentally responsible designs for a building of this type. This example illustrates some of the installed energy efficient technologies in an urban development of this scale.

Design Philosophy

The integrated design team working on 4 Times Square adopted a strategy which would consider the following criteria for the skyscraper:

· Energy Efficiency

· Indoor Ecology

· Sustainable Materials

· Responsible Construction

· Responsible Operations and Maintenance Procedures

Energy Efficient Features of 4 Times Square

Materials

Where possible concrete replaced steel in the structure of the building, hence reducing the embodied energy of the structure. Non toxic and biodegradable materials as well as Sustainably harvested wood were chosen and used in the construction of the building. Environmentally responsible construction was implemented with over 65% of debris being recycled.

Fuel Cells – Two 200kW fuel cells use natural gas to generate power to provide 100% of the nighttime electrical demand with hot water and carbon dioxide as the by-products. The hot water by-product is used to heat the building during winter.

Photovoltaics – Integrated into vertical curtain wall doubling as a façade on the top 19 floors of the southern and eastern faces of the building, hence, saving cost on alternative facades. They supplement a very small proportion of the buildings electrical use with up to 15kW of power.

Fans and Pumps – All have variable speed drives installed which provide significant energy savings. VSDs operate by varying the frequency of the power supply to the drive. Their benefit comes from the cubic relationship between power and speed:

Power consumed µ Speed³

Theoretically, a motor operating at 50% speed should consume only 12.5% of the power. In practice a combination of losses within the VSD and the disproportionate magnetising currents drawn by an induction motor running at low speed mean that the motor is drawing about 20% of the power at 50% speed.

Air Quality – Fresh air is supplied to the building at a high level to avoid the contaminated air from the traffic congested roads of New York City at ground level. The outside air is 85% filtered with the building circulating air fresh air on all floors of the building. Air handling units are controlled floor by floor to allow individualised control. Furnishings can be a cause of toxic fumes in a room and although it is the choice of the tenants as to which furnishings they choose, building developers of 4Times Square have provided a set of guidelines on the most benign furnishings and finishes.