BeavertonOregon.gov/bcp
Energy Efficiency
At the Beaverton Central Plant, energy efficiency is accomplished by aggregating loads, managing real time information, utilizing high quality, flexible equipment, and employing a sophisticated operating approach. The system evaluates the real time data, projects the future need, and provides “just in time” delivery of just the right amount of heating or cooling from the most economical source. More specifically:
Load Aggregation
By combining the heating and cooling demands from a number of buildings with different uses (office, retail, residential), the plant is managed to take advantage of the diversity of schedules and needs. Since not all loads are on at the same time (example, residential loads are highest in early morning and evenings, office peaks near midday) the overall size of the plant can be smaller. Further, the aggregation of loads means larger equipment which is typically more efficient (economy of scale) and cheaper per unit output. And finally, the aggregation of the equipment makes for more efficient operation and maintenance.
Cooling
The first stage of cooling uses fans that bring in the air outside and uses little energy. This is often referred to as an economizer cycle. Being located in a maritime climate has real advantages, as during nearly two thirds of the hours of the year we can utilize outside air for space cooling. The second stage of cooling, especially for data rooms which run warm and need constant cooling, is through the use of the cooling towers, often referred to as a water-side economizer (see Economizers). The only energy use is limited to pumps and fans to operate the tower loop which acts like a large “swamp cooler”. The third stage of cooling brings in the chiller for mechanical cooling, which is the most energy intensive. However, by using variable drives on all components of the system, even this source is highly efficient (see Hartman Loop side-bar).
Heating
Similarly, the first stage of heating begins with recovered heat from the internal gains (people and equipment) through recirculation of a portion of the air. The second stage comes from very high efficiency boilers (95%) called condensing boilers. There is a one mmBTU unit in the central Plant and a 2 mmBTU unit in the mechanical room of the health Club Building. The third stage is the high efficiency (85%) conventional 7 mmBTU boiler. Like the cooling system, the heating system uses variable drives on all pumps and fans to ensure high system efficiencies.
“Congratulations to Beaverton for leading the way in using energy wisely and providing cleaner air. We hope other cities and businesses will follow their example.”
— Stephanie Hallock
Director, Oregon DEQ
Beaverton Central Plant: BeavertonOregon.gov/BCP
Page Updated: Sunday, November 05, 2006Copyright © 2000-2008 City of Beaverton All Rights Reserved
