C A S E S TUDY P E A R L R I V E R T O W E R How Far Can You Go? B Y K Y R A Ep STEIN G uangzhou, China, has leaped the hurdle of energy-efficient buildings with a single bound, moving into a new era of efficient super-tall towers. The port city of 6.6 million, about 100 miles from Hong Kong, will soon have a new symbol of prog- ress — a 71-floor office tower using wind turbines, photovoltaics and about 60% less energy than an ANSI/ASHRAE/IESNA Standard 90.1-2004, Energy Standard for Buildings Except Low-Rise Residential Buildings base case. 2 2 HIG H PERFORMING BUILDINGS Winter 2008Left Depiction of Pearl River Tower Skidmore, Owings & Merrill LLP B U I L D I N G A T A G LANCE Building Name Pearl River Tower Location Guangzhou, China Size 2.3 million ft² Started 2006 Completed Estimated 2009 Use Office Building Cost Estimated $12 million more than a building designed to meet the minimum requirements of Standard 90.1 Distinctions Designed to be the most energy-efficient super-tall tower in the world B U I L D I N G T EAM Owner CNTC Guangdong Tobacco Company Architect Skidmore, Owings & Merrill LLP (SOM) SOM Project Team MEP Roger Frechette, P.E., project engineer, SOM’s director of sustainable engineering Architecture Russell Gilchrist, project architect, SOM’s director of technical architecture Structural William Baker, P.E., FASCE, Skidmore, Owings & Merrill LLP SOM’s structural engineering partner Management Tom Kerwin, FAIA, SOM’s Pearl River Tower is designed to be the most energy-efficient super-tall tower managing partner in the world. Wind Engineering Consultant Rowan Williams Davies & Irwin Inc. (RWDI) RWDI Project Team The Pearl River Tower, which will building code, which in the last few Ray Sinclair, Ph.D; Duncan Phillips, be the corporate headquarters for the years has become, in some cases, Ph.D.; Glenn Schuyler, Ph.D. CNTC Guangdong Tobacco Company, more stringent than Standard 90.1. Other Key Players was first designed as a carbon-neutral It still is expected to be the most Guangzhou Design Institute tower. But permitting (a lack of energy-efficient super-tall tower in the net-metering laws for commercial world, according to project engineer buildings) and cost issues whittled Roger Frechette, director of sustain- the efficiency predictions to a not- able engineering at Skidmore, Owings unimpressive 58% less than Chinese & Merrill LLP (SOM). Winter 2008 HIG H PERFORMING BUILDINGS 2 3 All of this, Frechette said, can be carbon-neutral tower building?” said Building-Integrated done cost effectively. The project, as Frechette. “Even though the current Power Generation currently designed, costs $12 mil- design is not carbon neutral, we’ve set Wind power — integrated into the lion more than a building designed a very high bar and we’re doing some- design of the building — is one of to meet the minimum requirements thing that hasn’t been done before. the tower’s distinct features. The of Standard 90.1 — all of which can We hope that we, and others, can building has four large openings in be recovered in about five years learn something from this process and the envelope, two on each of the two due to reduced energy costs and the maybe someone can beat that mark.” mechanical floors, which house four increased retail and office space that The bar is high, and many of the small wind turbines. smaller HVAC equipment freed up. building features are creating a stir Guangzhou’s typical wind speed “We wanted to know: how far can even now, two years before the tower is usually a fairly mild 9 mph at that we go? Is it really possible to create a is scheduled to begin operations. elevation, but the air is literally pulled C OOLING FROM Ab O V E , A IR FROM BELOW Of all the elements in the Pearl River Tower’s A ventilation system is still necessary energy-efficient design, the radiant cooling to bring in air for breathing; the system system is the biggest energy saver. In this designed will deliver necessary ventilation system, water flows through ceiling panels underneath floors that are already raised to and provides cooling from there. provide room for cable. In this design, swirled Frechette says that the team looked to diffusers bring a supply of fresh outside-only Germany for this technology — it is rarely used air into the space and help to mix the air. in North America and is unusual in China. This “once through” approach to ventilation Another record-breaker, the system will be the improves the health of the building by reduc- largest radiant cooling system in the world. ing the risk of occupant exposure to airborne Because cooling is delivered by water viruses and odors. instead of air (and no heating is necessary “We have a building that takes outside air, Skidmore, Owings & Merrill LLP in the tropical climate), the system does not filters it, puts it into the building and then need to move air to cool the building. This vents it from the building,” said Frechette. Radiant cooling panels in the ceiling provide saves the energy needed to run that equip- “Conventional buildings use recirculation to cooling; ventilation air is delivered from ment and the money to buy and maintain it. cool or heat air because the air has already below the floor. 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 Skidmore, Owings & Merrill LLP coil units and mechanical room fan and/or Air space between the two layers of the façade traps heat, which is vented out of each compressor noise. Modeling shows that Pearl floor before it can radiate into the space. River Tower occupants will enjoy spaces that are a quiet 25 NC. 2 4 HIG H PERFORMING BUILDINGS Winter 2008 D52241asjl_709157a.qxd 8/24/07 6:28 AM Page 1 SEE TOUCH COMPARE . New Products . New Technology . New Solutions . New Innovations Don’t Miss the Building Automation & Control Showcase AtTheWorld’s Largest HVAC&R Marketplace January 22-24, 2008 Tuesday, Wednesday, Thursday Javits Convention Center, New York, New York For FREE Registration: Over 1,800 Exhibitors www.ahrexpo.com Co-sponsors: Honorary sponsor: Endorsed by: AABC • ABMA • AFE • AMCA • BI • BPI • CABA • CTI • GAMA • GWAC • HARDI • IAQA • IIAR • LMA • MCAA • MSCA • NADCA • NAFA • NEBB • PHCC • RETA • RPA • RSES • SMACNA • SPIDA • TABB • USGBC • ZigBee Produced and managed by: Winter 2008tel: (HIG203)H221-9232 PERFORMING e-mail: [email protected] 2 5 info.hotims.com/15939-2 I N T E G R A T E D W I N D P O W E R The Pearl River Tower’s wind design is based relationship, Frechette said. Air is pulled on a small turbine (almost 10 ft or 3 m in diam- through the building, accelerating the speed eter) by English manufacturer Quiet Revolution. of the wind by more than two times — and Each of the design’s four turbines has a rated increasing its power potential by a factor performance of 10,000 kWh per year. of eight. P LL SOM pulled in the largest wind engineer- For this site, models showed that average errill ing and consultancy in the world to help wind speeds of 9 mph (4 m/s) will speed up M them with testing and modeling for the wind to as fast as 18 mph (8 m/s) when they are design — Canadian firm Rowan Williams sucked through the building openings. wings & O Davies & Irwin Inc. (RWDI). “In essence, one wind turbine located in RWDI’s models helped to size and place the one of the openings could theoretically pro- kidmore, kidmore, turbines and provided suggestions to SOM duce the energy of eight turbines somewhere S for selecting turbines —considering maintain- else,” said Frechette. “So, this building has Pearl River Tower design ability issues, noise, and vibration issues. power comparable to 32 turbines.” was based on a turbine One of RWDI’s tasks was to model wind The turbines are estimated to provide 1% of by Quiet Revolution. potential. Power potential for wind is a cubed the building’s energy needs. through the holes in the envelope by (about 2% of the building’s needs). and finally to the building’s wall the negative pressure on the leeward The wind and photovoltaic systems receptacles. Energy is lost along south side, accelerating winds to not only reduce the amount of elec- every step of the way, making that speeds of about 18 mph. tricity needed from the power grid to energy pathway about 30% efficient. Modeling and wind tunnel test- operate the building, but also create Generating electricity at the site ing show this design has a power a more efficient system altogether. where it will be used reduces the potential capacity of nearly 15 times SOM’s initial design also included losses that come from handling more than a typical stand-alone wind the capability of producing power and distributing it.