Towards Zero Energy, Pearl River Tower

Net zero energy concept is one of the hot topics in today’s green building industry. There has been a lot of research, modeling and optimization to achieve a building that is environmentally responsible and friendly. Pearl River Tower is a 71-storey building in Guangzhou, China with an area of 212,165 square meters. As Guangzhou experiences some of the worst air pollutions in China, Chinese government set the goal of reducing carbon emission by 10% by the end of 2010. The goal of constructing such a building was to build a transformed, integrated, high performance, environmentally responsible design. 

The energy saving systems of this building would work together efficiently to consume approximately 60% less energy than a conventional building. This high performance building is designed in such a harmony with its surrounding environment that it extracts energy from the natural wind and sunlight. Furthermore, it has been considered as the largest radiant-cooled office building in the world and the most energy efficient super tall building in the world (1016 ft) since completion in March 2011.

There are 4 strategies that had been taken for achieving net zero energy which are Reduction, Reclamation, Passive Absorption and Generation. For instance in reduction strategy, instead of normal air conditioning and ventilation systems, chilled radiant ceiling through perimeter chilled beams is utilized. It functions with pumping cold water (58˚F) through copper pipes in the slab which cool curved metal plates used for the ceiling system and metal fins for the perimeter, consequently cooling the surrounding air. Also, the displacement ventilation function provides cooled fresh air and delivers it via a raised access floor. High performance glazing systems, daylight responsive controls, high efficacy lighting and high efficient office equipment are the other features that have been used for the reduction strategy.

Reclamation is another strategy that has been used for seeking net zero energy. Chiller heat recovery, generator heat recovery and exhaust air heat recovery are other features that utilized for providing a pleasant indoor air quality for the building in four seasons of year with different temperature and humidity conditions. Also, condensate reclamation system harvests water from chilled surfaces to control interior humidity. Water is filtered and used for interior plantings and toilet flushing. Furthermore, Solar energy is collected within the double wall facade. The energy is transferred to the mechanical floors and is used as heating for the dehumidification system.

Another useful strategy is passive absorption. Advanced wind and solar technologies were incorporated into the design of this skyscraper in order to generate or “absorb” the natural energy from the building’s surroundings. The Tower is positioned so that the broadest side of the building faces directly into prevailing winds. In addition, Photovoltaic cells were utilized into the mechanized shade system to capture the sun’s energy in the eastern and western facades.

Furthermore, in order to implement generation strategy, this tower needed to use a comprehensive micro-turbine system to fulfill its excess energy demand. These small, highly efficient turbines would run off of anything from biodiesel to natural gas, making the Pearl River Tower a mini power plant. However, Guangzhou authorities did not warm up to the idea. Their reluctance coupled with the faulty electrical grid led to these micro-turbines being put on hold.

Also, if you are interested, you can watch these two videos about the tower.

http://ctbuh.org/TallBuildings/VideoLibrary/ConferenceVideos/2009_Chicago_S8_Gilchrist/tabid/1968/language/en-GB/Default.aspx/

http://www.youtube.com/watch?v=hBJsTwkQoAc