Trigeneration | How It’s Creating World-LEEDing Buildings

1315 Peachtree Street

Renewable energy and energy efficient technologies are generally lauded for their inclusion in projects but, while we understand they are relevant, we often do not understand exactly what they do and how they make energy savings possible.

This is an imprecise way to practice, and can lead to greenwashing of the public and the industry and cause industry members to miss out on opportunities to implement highly efficient green technologies due to a lack of education.

One technology sneaking under the radar is the trigeneration system. While the systems themselves are growing in popularity, there is little promotion of exactly what they do and why they are so successful.

As the name would suggest, a trigeneration system is the simultaneous producer of the three energy forms: electricity, heating and cooling. Waste heat gathered from the generation of electricity – which is created through solar collectors in high energy efficiency systems – is captured by the system and is then used to heat and cool water. An absorption chiller, which is powered by the captured heat, operates like a refrigerator, creating low temperatures which can be channeled into air-conditioning systems. The use of wasted energy and the close-range electricity exchange allow some systems to run at 80 to 90 per cent energy efficiency levels. This is a marked increase over the 35 per cent efficiency level achieved by conventional on-grid energy.

1315 Peachtree Street terrace

The winners of this year’s American Institute of Architects’ Committee on the Environment (AIA-COTE) green building projects showcase the success of this energy efficient technology.

As part of the ‘AIA Top Ten’, architectural firm Perkins + Will’s redevelopment of a midtown Atlanta building at 1315 Peachtree Street, which was originally built in 1986, is a prime example of how the trigeneration system can be implemented into a project.

Due to the fact that the designers were dealing with an already built structure, certain ‘ground up’ sustainable design principles, including extensive solar orientation planning and the widespread use of low embodied energy structural materials, were not possible given that only 9 per cent of the retrofit was to be newly built. In order to make up for some of these limitations while still creating a high-performance office building, a trigeneration system has been included. The system incorporates microturbines on the office building’s roof, allowing the system to run completely on natural gas, reducing the overall carbon footprint by 68 per cent.

Due to this system, along with a number of further green technological implementations, the building has achieved the highest LEED platinum score in the northern hemisphere, making it a leading structure in the green building sector.

“1315 Peachtree Street exemplifies the kind of environmentally sustainable measures that can be taken during a building retrofit,” says Rick Fedrizzi, president, CEO and founding chair of the U.S. Green Building Council (USGBC). “It has earned its high LEED score and will continue to pay dividends through energy saving measures for decades to come.”

Trigeneration systems are making the most out of wasted energy, reaping environmental and economical reward. Now, they are also earning critical acclaim and being recognized for their contributions to green building excellence.

By Emily D’Alterio

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