Science Academy wins Sustainable Development Awards
The California Academy of Science was rebuilt for energy efficiency and the new building opened to the public in September last year. The building is still winning awards for sustainable development into 2009 and recently earned the Environmental Protection Agency’s regional Environmental Award and became the sole winner of the international Holcim Award for Sustainable Construction.
The museum is situated in San Francisco’s Golden Gate Park and uses a low horsepower water pump system that serves as an air-conditioning and heating system for the entire building. Although the system costs more upfront and is not a portable air conditioning and heating system, Paul Switenki, one of the project’s engineers, says that due to the long life cycle of the building they had to choose a system for energy efficiency, above all else. The roof supports a living environment with plants indigenous to the region to keep the whole project as environmentally friendly as possible.
The temperature control system works through pipes in the floor. The under-floor heating and cooling made sense as the galleries have very high ceilings so it would be difficult to heat or cool with air from the ceiling and high horsepower fans would use a huge amount of energy for the large museum. The system was engineered by the company, Arup and installed by O’Brien Mechanical. The system consists of 100,000 linear feet of tubing connected to six, 20,000-Btuh boilers and three, 4-ton chillers.
The system works by pumping water through the under-floor pipes. To heat the building, the water is heated by the boilers and circulated through the pumps that push the water through heat exchanges to transfer the heat to manifolds connected to the tubing. The building is heated in the early mornings and doesn’t need to be reheated much as the building stays at a comfortable temperature throughout the day.
The cooling system is similar but runs through a system of chillers, rather than boilers. The extensive use of glass in the galleries requires a cooling system for warmer days even though the temperature is mild in the region throughout the year. Paul Switenki said, “Since we were using the PEX tubing for heating, we figured we might as well use it for cooling. On those days when the ambient outdoor temperature is 80˚F or warmer, the chilled-water cooling may be used to ‘top off,’ or augment, the natural ventilation system that is part of the design”.
O’Brien project manager Randy Payne said on the installation process: “To tackle a radiant project of this magnitude was a big undertaking. We had to sit back and plan carefully, testing our ideas before going all-out. But in the end, it didn’t prove super-difficult”.
