SOLAR TODAY Blog


>>Adventures in living renewably
November 24, 2008, 7:34 pm
Filed under: Electric fun, Transport

An update from the do-it-yourself scrounger:

Electric commuting: I now have a couple of months’ experience riding the Yamavolt electric motorcycle conversion to work and around town. The bike runs very nicely, thank you.

Real-world experience suggests that, in future, recharging infrastructure is going to be critical. I have no trouble riding to work and back because, thanks to our set-up at the office, I can recharge the bike in the warehouse. But running errands downtown is a problem, because I can’t recharge while shopping. When this set of batteries poops out I’ll invest in a NiMH pack to double the range.

Charging overnight

Charging overnight

If I worked in an office without a recharging outlet in the parking structure, or if I lived in an apartment building, electric commuting would be sketchy. I’d have to run a very long extension cord out some window and out to the parking lot.

Even with my own parking slot with a dedicated recharging outlet, I’d want the vehicle to have at least three times the necessary range — 30 miles for a 10-mile commute — to assure being able to get home if charging weren’t available at work. In future, every parking meter and garage space ought to be a charging station. In 20 years, parking vendors should be retailing kilowatt hours instead of renting tiny patches of real estate on an hourly basis.

If I were in the inverter/transformer business, I’d be gearing up now to serve the future auto-recharging market. If I were an architect, I’d be figuring out how to wire parking garages for overhead charging circuity.

Solar water heating: I made progress on my cobbled-up solar water-heating system over the weekend. The Butler Sun Systems heat exchanger wand was a ten-minute job to install in my water heater tank. Just open the 230-volt circuit breaker, shut the cold-water feed valve, drain a few gallons out the bottom of the tank through a garden hose, and disconnect the one-inch hot-water-out line. That revealed a collar inside the tank measuring 3/4″ across, too narrow to admit the heat exchanger wand, which has an outside diameter of 7/8″.  I broached the thin steel collar with a 7/8″ hole saw, in about 10 seconds flat.  Used the hole saw instead of a 7/8″ bit because its smooth sides wouldn’t damage the water-out threads. The wand then slipped straight in and snugged down quickly. I had hot water again in three minutes.

The next step was to pressure-test the 30-year-old collector boxes on the roof. I bought these at salvage a couple of years ago for $30 each, and they’re a standard 4’x8′ insulated-box design with copper fin tubing inside and tempered glass outside. I have two of them canted 40 degrees from vertical facing dead south, and soldered them together last week. I rigged plastic tubing to the four outlets with a pressure gauge, a ball valve and a fitting to take the garden hose. When I turned on the water, the system filled up quickly. I closed the valve and checked the gauge: it showed 130 lb, the city water pressure.

90px-old_faithful_geyser_calistoga_californiaBut the water heated up quickly and at 140 lb. one of the soldered joints between the two panels began to weep. Then it bubbled. Then one of the plastic tubes blew off at the top, with a sound like a very large champagne cork headed for orbit, and a geyser of steam shot out.

You should have been there.

I drained the system into a five-gallon bucket and found I’ll need about three gallons of propylene glycol.

Next step is to separate the panels and connect them again with solder-free unions. Soldering those joints is tough for two reasons: They butt right up against the aluminum frame, so it’s hard to get at them; and the internal fin-tubing functions as a fabulous heat sink. It takes a long time and a hot flame to make the solder flow evenly. The end of the copper pipe sags and doesn’t want to stay round.

Anyway, it’s nice to know that this system will boil water even on a late-November day in Colorado.

Onward!

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2 Comments so far
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Effective Dec. 9, 2008, the SOLAR TODAY blog has moved to http://solartoday.org/blog

Comment by Seth Masia

Interesting Read! Very detailed blog.
Thanks for sharing

Comment by elinorloewen




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