| The Fariborz Maseeh College of Engineering and Computer Science building is the latest to go green at Portland State University. |
Since 2002, Oregon’s Portland State University (PSU) has focused on designing new buildings and retrofitting and renovating older campus buildings with sustainability in mind. Several PSU buildings serve as models of these kinds of innovative sustainable design and construction projects.
The new engineering building in the university’s Northwest Center for Engineering Science and Technology is PSU’s latest building to “go green.” Formerly called the NW Center, the engineering tower houses PSU’s Maseeh College of Engineering and Computer Science. The U.S. Green Building Council has rated the engineering building as Leadership in Energy and Environmental Design (LEED) Gold-certified.
The building features natural lighting, natural ventilation of its five-story atrium, a rainwater harvesting system that supplies water for toilets and urinals, and geothermal heating and cooling from underground springs. The project’s integrated design process has made the engineering tower a model for energy and resource efficiency.
Both Siemens Building Technologies and Siemens Water Technologies were part of the engineering tower project team and contributed a variety of energy and water efficiency-driven technologies, systems and services that helped make the Maseeh College of Engineering and Computer Science’s building both “smart” and “green.”
Energy efficiency
Siemens Building Technologies supports PSU’s sustainability initiatives through a number of energy-efficient strategies supported by innovative systems and technology integration. For the engineering tower, Siemens provided integrated heating, ventilation and air conditioning, as well as specialized laboratory environmental controls via the company’s APOGEE Building Automation System.
As part of PSU’s sustainability strategy, Siemens controls the geo-thermal water flow that is pumped from two separate aquifers and used for heating and cooling. As mentioned, rainwater is used to flush toilets, and the APOGEE system controls the water flow for this application. Siemens’ building automation systems also control the motorized operable windows and provide indoor air quality measurement and control via CO2 sensors.
The APOGEE control system is also integrated with the building system for fan control or shutdown in the event of a life-threatening safety condition (e.g., smoke containment and management). Siemens also provides preventive maintenance and emergency repair services to the university.
Water efficiency
A portion of the rainwater collected from the engineering building’s roof is diverted through PSU’s rainwater harvesting system, located in the hydrology lab on the second floor. The treated rainwater is used to flush toilets and urinals on the first floor. Students are using the rainwater harvesting system to study water usage rates, rainwater quality, filtration methods and other aspects of environmental engineering in an effort to advance this technology.
With the rainwater harvesting system, water flows via gravity from the roof to a settling basin or sediment tank. In the sediment tank, large particles in the rainwater are settled out. When level controls indicate a high water level, a sump pump transfers the untreated water from the sediment tank to a 1,000-gal storage tank. Level alarms that control the water level in the storage tank divert water from the roof to the city’s water treatment facility when the tank level is high. Fresh make-up water from the city water supply is used if the water level is low.
From the storage tank, a water sample is continuously pumped through a flow cell in Siemens’ Strantrol 890 controller system. Using water in the flow cell, the system monitors and compares oxidation-reduction potential to a target setpoint. The system then pumps sodium hypochlorite from the 50-gal hypochlorite chemical tank into the rainwater storage tank as needed to maintain the target setpoint.
PSU’s rainwater harvest system also uses two ultraviolet (UV) systems to disinfect the water. In a single-pass operation, water passes through UV treatment as it is pumped to the point of use. The second UV system has a sidestream treatment design that continuously treats rainwater in the 1,000-gal storage tank. An additional distribution and filtration skid, which is an integral part of the rainwater system, delivers the treated water from the storage tank to the building fixtures.
The university used only treated rainwater for toilet and urinal flushing during the rainwater system’s first eight weeks of operation. During this time, no city water was used for these functions.
Green buildings
With the help of Siemens’ energy- and water-efficient technologies, PSU uses 45% less energy than Oregon Code and nearly 40% less water than in previous years.1
PSU has three additional green buildings on campus: the Native American Student and Community Center, the Broadway Housing Building and the Stephen E. Epler Hall. The latter two are LEED Silver-certified. Siemens Building Technologies provided building control solutions for all three buildings. For the Broadway Housing Building, Siemens worked with the university’s engineering department to develop a way for students to monitor the eco-roof soil temperatures, water runoff and building energy usage for various cost centers.
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