Monday, July 26, 2010

365 days with solar

One year ago today my 4928 kilowatt/hour (5 kW) solar solution went live, magically collecting light and converting it into energy. Since then, I’ve produced 7,835.38 kWh of electricity. That’s the same as 7.8 megawatts.
Thanks to Net Metering, I’ve managed to sell an average of 10% back to the utility throughout the year. This occurs any time when I’m generating more electricity than the house is consuming, so excess is returned to the grid at the same rate I’m billed for it.
The daily average over twelve months was roughly 21 kWh each day with a standard deviation of about 7.8. The best two week period was the February / March border. Between February 25, 2010 and March 10, 2010, I had seven of my top ten days and averaged 27.29 kWh. The best day on record was March 4, 2010; the system generated 34.12 kWh. Mid-March to Mid-April 2010 saw a number of clear, cool, sunny days, and I sold 25% back to the utility during this time.

All told, the data I’ve collected suggests my installation has accounted for 35% of my electricity over the past year.
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Tuesday, March 30, 2010

coolest place on earth

cernlandCERN's Large Hadron Collider was the coolest place on the planet (-271.3°C, to be precise) to be today when it began smashing particles traveling at 99.99% the speed of light together at 3.5 TeV, or 3.5 trillion electron volts. Collisions are expected to generate heat at 100,000 times the hottest part of our sun, but they'll be super tiny,  so we don't need to worry about any microscopic black holes, strangelets, vacuum bubbles, or magnetic monopoles.

It's expected the six experiments will soon begin to yield clues about the origins of our universe and answer nagging questions such as "where IS all that antimatter, anyway" and "are you SURE you only live in three (ok, four) dimensions?"

It's absolutely fascinating how the project has evolved from an idea in 1984 to a reality today, shattering one physics record after another as it tugs on Humanity's most primal desire to just obliterate stuff. In this case, however, and all jesting aside, the destructive forces are necessary as we look for clues about the origins of our universe and how we can explain it all.

But for me, that's a bit of a problem. My Sophomore year in college, I failed Calculus. I should have never taken it. I believed then, as I do now, it's ego-maniacal to claim we can explain it all in elegant fashion just using numbers. If you only ever knew of a hammer, you'd never benefit from a screwdriver. Ergo, it's difficult to build furniture if you have to invent the screwdriver along the way. I don't think we have all the tools, at least not yet. It's crippling to think we can manipulate numbers to prove something, then come up with complicated rules and offer exceptions when we need to craft them to fit something which just doesn't fit. Special Relativity led to General Relativity but wait, General Relativity excludes quantum physics. So off we go to find new numbers, or number theory, to explain it. I could never get my head around Calculus because I didn’t trust the numbers; I just didn’t believe them.

Sure, we'll learn a lot and LHC is going to take us tremendous distances. In fact, I'm hoping LHC will likely help us find evidence of screwdrivers (so to speak), so we can get closer to explaining it all. I just have a funny feeling the last explanation when it's all sorted won't have any numbers in it at all, or least not a number the way we know it today.

Tuesday, October 6, 2009

ases solar tour 2009

solar tour We were extremely honored to showcase our house this past Saturday as Tampa Bay’s Featured Home on American Solar Energy Society's National Solar Tour. Although this is the tour’s fourteenth year, this was the first one locally. The tour began at the University of South Florida’s Clean Energy Research Center with speakers presenting information about solar energy. After an hour, it kicked into high gear and everyone dispersed. With four busloads visiting us (two at once, at one point) and a number of independent explorers, we estimate more than 150 people dropped by to check out our solar solution.

This is what they came to see:

1    SMA Sunny Boy SB5000US Photovoltaic Inverter
22  Sharp ND-U224C1 224W solar panels
1    SMA Sunny Island 5048U Inverter
8    Discover EV305A Lead Acid Batteries
1    Alternative Energy Technologies AE-28 4x7 Solar Water Collector
2    SunRise 1050 Solar-powered Attic Fans

Since our go-live in mid-July, we’ve generated an average of about 22 kWh a day, which is about a third of what it takes to power our home in the summer. We recently had a 24 hour window in which we didn’t need any air conditioning, and the system came very close to providing all of our electricity needs (we netted a take of four kWh from TECO).

I spent the day explaining numbers like this, the return-on-investment model, how the system operates, and answering everyone’s questions. I even spoke to WMNF when they came by. It was a lot of fun and hope I can participate again in some way next year.


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Friday, October 2, 2009


solar We wanted our new home to be as efficient as possible. We were fortunate, the builder we selected used energy-efficient materials and methods as part of their normal processes. To extend what they were doing during construction, we applied mastic to seal the duct-to-vent connections, upgraded to 16 SEER heat pumps with variable speed air handlers, and selected extremely light colored roof shingles to reflect light and heat.

photovoltaic Still, we knew it would be costly to operate a large two story home where air conditioning is an indisputable need. So after construction, we added ceiling fans to many of the rooms, tinted the windows to block ~50% of radiant energy, installed frame-mounted plantation shutters to block as much light and heat as possible, replaced nearly all of the incandescent light bulbs with CFLs (Compact Florescent Lighting), and jumped in to solar energy with both feet.

installation Our solar installation consists of four discrete technologies. We installed twenty-two photovoltaic (PV) panels on the south roof to capture the sun's energy, rated at a maximum output of 4.928 kilowatt hours. The grid-tied inverter converts the PV energy into electricity. This electricity augments Tampa Electric (TECO)'s feed from the street and also charges our battery back-up system. The eight lead acid batteries in a cabinet provide UPS-like back-up electricity to our critical load items such as the refrigerator, the microwave, telecommunications equipment, and the solar hot water heater. The solar hot water heater works by sending water to a 4'x7' panel on the roof where it's heated and returned to the insulated holding tank. To help reduce the extreme heat in the attic, two self-contained solar powered attic fans pull hot air up and out anytime it's light outside and the attic temperature is above 86 degrees.

            battery backup  meter

Each morning as the sun rises, the panels begin generating energy. The first priority is the batteries. Once fully charged, the energy from the panels feeds the house. Excess electricity is placed back onto the electrical grid, spinning our meter backwards and crediting our account because of our net metering agreement with TECO. Should we experience a disruption of electrical service, our back-up system engages. The solar hot water pump is on a critical load circuit, so as long there's sunlight to re-charge the batteries, we'll always have hot water and electricity.

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