High Performing Buildings - Winter 2008 - (Page 35)

4 Times Square was the nation’s first green high-rise. are assumed that do not occur in operation. For example, daylighting strategies might assume that artiﬁcial lighting is dimmed or turned off, while operators or occupants often do not understand the control systems and so do not use them as intended. Also, lack of commissioning can result in systems that are not operating as designed, frustrating operators and occupants. To manage expectations for energy performance, the design team must understand operational expectations from the beginning of the project. In one recent example, the new LESSONS LEARNED Commissioning and Owner Involvement At 4 Times Square, commissioning played an important but limited role in identifying shortcomings in the design, along with construction deficiencies. This allowed the building to become fully operational much earlier following completion than other buildings in the Durst portfolio. But, because the team was engaged during the final stages of construction, the process was less efficient than it could have been. At One Bryant Park, we engaged the commissioning team much earlier during the design process and before construction began. This was to ensure that the building will operate to design intent and efficiency level from day one. As an additional benefit, early involvement allows the commissioning agent access to systems that would normally be inaccessible and hidden by the time the typical schedule would commence. The commissioning team is also much larger than the team at 4 Times Square, allowing for increased system testing, surveillance and inspection. Partly due to the commissioning process, we (as owners) have also been much more involved in establishing design intent and goals and have had much more oversight during the design and construction process. Based on our experience with the 4 Times Square building, a variety of changes have been made in the design of our next project, the Bank of America Tower at One Bryant Park, currently under construction and expected to be completed in 2008. From the lessons learned at 4 Times Square, a number of things are being done differently at this new 2 million ft2 tower being built on the same block. Fuel Cells The 4 Times Square design includes two 200 kW natural gas-powered phosphoric acid fuel cells. The cells currently produce about 10% of the annual electric energy used in the building. After the building was operational and actual production results could be recorded, we realized that, though fuel cells work, from a fiduciary standpoint this application and design was not the best use of the technology. The two fuel cell units consume a large amount of space that is out of proportion to the actual amount of power being produced. In midtown Manhattan, the price of this office space is at a premium. Also, the units have turned out to be very maintenance intensive, and installation costs were much higher than expected. Finally, the waste heat recovered from them is low-grade and not very useful. At One Bryant Park, instead of a fuel cell, a gas turbine is being used to achieve energy production goals in a more dramatic way. The turbine is the first installation of its kind at a commercial office building and is expected to produce 4.6 MW, providing about 70% of the building’s annual energy needs. In addition, the waste heat from the turbine will be used to heat and cool the building. Photovoltaics A similar series of problems occurred with the building-integrated photovoltaics installed at 4 Times Square. After seeing that installation costs were much higher than expected and that production rates were much lower than expected due to the vertical orientation of the photovoltaics in the building’s façade, we realized that this technology was not best applied in a Manhattan highrise office building. At One Bryant Park, we resisted the desire and pressure to include building-integrated photovoltaics. Winter 2008 HIGH PERFORMING BUILDINGS 35

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High Performance Buildings - Winter 2008 Passing On the Gift: Heifer International Headquarters Head of the Class: University of Florida’s Rinker Hall How Far Can You Go? Pearl River Tower The Proof Is Performance: How Does 4 Times Square Measure Up? Lighting the Way: Two Guilford County Schools Montreal’s Retail Example: Mountain Equipment Co-op® (MEC)

High Performing Buildings - Winter 2008

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