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CCAT MEOW

244 bytes added, 13:24, 8 November 2012
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Image:MEOW Rack Jerome.jpg|Fig 3: Jerome (HSU student Jerome ) filing one of the beams in John's shop.Image:MEOW Rack Dustin.jpg|Fig 3a: Dustin (HSU student Dustin ) doing some precision metal cuttingImage:MEOW Rack Jess.jpg|Fig 3b: Jess (HSU student Jess ) making sure it will all fit together.
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===Wiring the System===
Because CCAT is mainly a teaching and demonstration facility, we decided to take the reconstruction process as an opportunity to give a free PV system wiring workshop to HSU students and community members. The workshop was led by the Arcata based solar company Roger and His Band of Merry Solar Installers (*ADD PHOTOS*). Held over two separate weekends, the workshop series was very successful where over 20 participants learned the basics of PV wiring and left with the satisfaction of contributing to a fully functional solar system![[File:MEOW Wiring Workshop.jpg|thumb|Fig 4: HSU students being instructed on how to wire the PV system.]]
The four panels of the array were all wired in series (i.e. four series with one parallel string). This configuration simplified the wiring process and made the system safer by allowing less DC current to pass through the lines. Initially, we had some concern that the 150 V limit of the charge controller would be surpassed in an all series configuration. If all four panels were to be simultaneously open-circuited the system voltage would total 147 V (36.8 V x 4 panels); if one considers a safety factor of 1.25 (representing a cold morning with full sun) the system voltage could spike to 184 V and possibly fry the charge controller. However, after consulting with Roger and his professional team, they informed us that this situation is highly unlikely due to the flat (0°) tilt of the array, the local solar resource, and shading profile at the CCAT house.
The Table below shows the monthly and annual estimates for the amount of electricity (kWh) the MEOW V2 is capable of producing. The calculations use [http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/sum2/24283.txt NREL data] for the solar resource in Arcata, CA at a horizontal tilt (2nd column) and the monthly shading profile in the CCAT driveway according to a solar path finder reading (3rd column). The calculations are for the 920 W, flat-mount (i.e. 0°) array and consider a total system efficiency of 85% (93% for the inverter, 95% for the batteries, and 96% for wire losses and module soiling). The calculations estimate that the MEOW will produce roughly 870 kWh/year, which could change based on how often the trailer is moved from the CCAT driveway as well as the depth of discharge (DOD) that the batteries are cycled to. [[File:MEOW Pathfinder1.jpg|thumb|Fig 5: Solar Pathfinder reading on top of the MEOW while parked in the CCAT driveway (Credit: Nicholas Riedel)]]
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