Last week, Roger Frechette, Director of MEP Engineering and Russell Gilchrist, Director of Technical Architecture, of SOM spoke about the Pearl River Tower in Guangzhou, China. Originally conceived to be a net zero-energy building, regulations and economics have gotten in the way during the design process, but they still estimate that the building uses 60% less energy than a typical office building in China (the energy code in China is actually stricter than that in the US).
Some of the major design components of the building are as follows:
- Wind turbines are built in to two mechanical floors on the building, two per floor for a total of four turbines. These turbines actually reduce the wind pressure on a tall building, allowing for reduced concrete in the structure.
- Water, not forced air, is used for building cooling. A radiant cooling system allows for the buildings HVAC system to be 1/5 the normal size, and also improves indoor air quality since the air is not recycled within the building. This also allowed the building to save significant space on each floor (21 meters in total), so that the building has 5 more stories than a comparable sized building.
- A 2MW microturbine fueled by methane (from coal plants and landfills) that serves independent from the city grid, generating power at the peak so that if the power goes out during the day, the building isn’t affected, and it can generate power to the grid at night when the building demands are minimal. A side product is that the heat generated by the turbine can be used to generate hot water for the building. Improves energy efficiency significantly because the grid typically operates at 30% efficiency from the power plant to the end of the line, vs. 80% efficiency when the plant is in the basement. This component won’t actually be built, though, since the city won’t allow a commercial building to sell power back to the grid. The engineers have left space for the turbines in case the regulations change.
However, the most interesting aspect of the building discussed may have been the economic analysis. Between the reduced operating costs due to lower energy demands, and the extra floor space available for rental, Mr. Frechette calculated that the payback for additional costs for the sustainable design components in this building, as compared to a comparably sized office building in China, is 4.8 years. In other words, in a 5 year life cycle cost, this building actually is cheaper to build and operate than a comparable building. And that is without selling any excess power to the grid.
If we can figure out a way to learn from this design and bring down the life cycle costs of residential buildings to the same range, then it is almost guaranteed that people of all income brackets, not just the wealthy, will all start demanding green design.
Image from World Architecture News
Posted by Dahlia T.