High Performing Buildings - Winter 2008 - (Page 24)

All of this, Frechette said, can be done cost effectively. The project, as currently designed, costs $12 million more than a building designed to meet the minimum requirements of Standard 90.1 — all of which can be recovered in about ﬁve years due to reduced energy costs and the increased retail and ofﬁce space that smaller HVAC equipment freed up. “We wanted to know: how far can we go? Is it really possible to create a carbon-neutral tower building?” said Frechette. “Even though the current design is not carbon neutral, we’ve set a very high bar and we’re doing something that hasn’t been done before. We hope that we, and others, can learn something from this process and maybe someone can beat that mark.” The bar is high, and many of the building features are creating a stir even now, two years before the tower is scheduled to begin operations. Building-Integrated Power Generation Wind power — integrated into the design of the building — is one of the tower’s distinct features. The building has four large openings in the envelope, two on each of the two mechanical ﬂoors, which house four small wind turbines. Guangzhou’s typical wind speed is usually a fairly mild 9 mph at that elevation, but the air is literally pulled COOLING FROM ABOVE, AIR FROM BELOW Of all the elements in the Pearl River Tower’s energy-efficient design, the radiant cooling system is the biggest energy saver. In this system, water flows through ceiling panels and provides cooling from there. Frechette says that the team looked to Germany for this technology — it is rarely used in North America and is unusual in China. Another record-breaker, the system will be the largest radiant cooling system in the world. Because cooling is delivered by water instead of air (and no heating is necessary in the tropical climate), the system does not need to move air to cool the building. This saves the energy needed to run that equipment and the money to buy and maintain it. A ventilation system is still necessary to bring in air for breathing; the system designed will deliver necessary ventilation underneath floors that are already raised to provide room for cable. In this design, swirled diffusers bring a supply of fresh outside-only air into the space and help to mix the air. This “once through” approach to ventilation improves the health of the building by reducing the risk of occupant exposure to airborne viruses and odors. “We have a building that takes outside air, filters it, puts it into the building and then vents it from the building,” said Frechette. “Conventional buildings use recirculation to cool or heat air because the air has already Skidmore, Owings & Merrill LLP Radiant cooling panels in the ceiling provide cooling; ventilation air is delivered from below the floor. Skidmore, Owings & Merrill LLP Air space between the two layers of the façade traps heat, which is vented out of each floor before it can radiate into the space. been cooled, and it saves energy. We aren’t using air for cooling, so the small quantity of air we bring in from the outside, for breathing, is not that expensive or difficult to cool.” Because there is no need for large volumes of air and minimal fans, the shafts that run vertically through the building are smaller, saving space that can be used for office and/or retail space. These systems also are quieter than the conventional design. A typical office floor in a United States building would be designed to have noise levels around 30 to 40 NC (noise criteria scale) — it’s difficult to get levels lower than that due to VAV boxes, fan coil units and mechanical room fan and/or compressor noise. Modeling shows that Pearl River Tower occupants will enjoy spaces that are a quiet 25 NC. 24 HIGH PERFORMING BUILDINGS Winter 2008

Table of Contents Feed for the Digital Edition of High Performing Buildings - Winter 2008

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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