The San Dimas Technology and Development Center (SDTDC) in southern California uses about 370,000 kilowatt hours (kWh) of electricity and 10,000 therms of natural gas per year. The center recently implemented energy-efficient improvements and installed a photovoltaic (PV) system (figure 1) using American Recovery and Reinvestment Act (ARRA) and Forest Service facilities funds.
Some of the improvements at the center include a small, energy-efficient motor in the spark arrester laboratory that replaces a 150 horsepower motor from the 1950s. A new energy-efficient heating, ventilating, and air conditioning (HVAC) system replaces a 1960s HVAC system. Energy-efficient lights were installed with the help of the California Conservation Corps (figure 2). Plug load sensors at each desk conserve energy when peripheral equipment is not in use and occupancy sensors for all overhead lighting replace traditional light switches.
Because ARRA funding had a strict timeframe, design and build proposals for the PV system were solicited from prequalified General Services Administration photovoltaic system contractors. Three proposals were received and included expected outputs of 363,599 kWh per year, 369,674 kWh per year, and 594,091 kWh per year. The proposal offering the highest expected output was chosen.
Project specifics include:
- 1,288 solar panels rated at 235 Watts each.
- Each panel contains 60 high-quality polycrystalline silicon wafer solar cells.
- All panels are mounted on ground racks with a fixed tilt of 20 degrees (facing south). The panels occupy about 1.5 acres protected by security fencing and cameras.
- Panels are connected into "strings" to build voltage.
- Strings are connected in parallel to build current.
- Strings are connected to an inverter with a maximum capacity of 250 kilowatt hours alternating current (kWh AC) and an efficiency rating of 97.5-percent for converting direct current to alternating current.
- The inverter is connected to the Southern California Edison (SCE) service entrance and uses smart meters for monitoring power production and usage. May is usually the highest output month (60,729 kWh AC); December is usually the lowest output month (35,483 kWh AC).
The PV project will produce enough energy to meet or exceed the center's total energy use (figure 3). Excess electrical power generated on sunny days will be bought back by SCE.
For more information on the SDTDC energy-efficiency improvements, please contact:
909–599–1267 ext 299
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