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Solar Electric Airplane


EdEarl

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For all you flying buffs, here is a tech toy to put on your wish list, at the moment a bit expensive for most of us.

nationalgeographic.com

Shortly before 5:00 a.m. Saturday EDT, a solar-powered aircraft named Solar Impulse took off from a runway at Washington Dulles International Airport. The plane, piloted by André Borschberg, is heading to New York's John F. Kennedy International Airport, where it is expected to land around 2:00 a.m. EDT (11 p.m. PDT) on Sunday.

When Solar Impulse lands, it will be the first plane to travel across the United States during both the day and night without using any fuel. The aircrafta Swiss-based projectstarted its journey on May 3, 2013, at Moffett Airfield near San Francisco, and has since made stops in Phoenix, Dallas, St. Louis, Cincinnati, and Washington, D.C.

This flight demonstrates that personal pleasure flying can be green, except for battery technology that typically uses environmentally unfriendly chemicals. However, work on ultracapacitors and greener batteries should eventually green electricity storage too.

 

See also:

http://www.solar-flight.com/

http://www.solarimpulse.com/

Edited by EdEarl
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However, work on ultracapacitors and greener batteries should eventually green electricity storage too.

 

Better would be work on more effective solar panels, to have more than 15% from m^2. And install them everywhere possible as standard coverage of every house and building.

But it's against gas&oil and energy industry interest. They need clients to give them money every month. Solar panel is sold once, and then client is gone.

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Yes! Apparently the price of solar panels is low enough to be competitive with oil and coal fired power plants.

 

computerworld

The cost of installing photovoltaic solar arrays has dropped to $3 per watt of electricity they produce - about the same as coal-powered plants cost to build - creating a watershed moment in the development of clean energy, experts say.

 

 

http://www.greentechmedia.com/articles/read/chart-2-3rds-of-global-solar-pv-has-been-connected-in-the-last-2.5-years

http://www.kare11.com/story/news/local/2014/03/09/solar-power-demand-outstripping-mn-subsidy-program/6229989/

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Yes! Apparently the price of solar panels is low enough to be competitive with oil and coal fired power plants.

 

But efficiency is not good. 15% from 1050 W/m^2 is 157 W = 157 J/s.

I am using a lot of energy (server is running 24h) in comparison to mine neighborhoods 2-3 times more. 417 J/s average = 10 kWh per day.

There would be needed 3 m^2 of solar panels if Sun would shine all the time, the same strength.

So actually we would have to double-triple if not more that area and somehow store energy to use at dark and night stage of day.

 

Another lost of energy is having to convert low-DC low-voltage of solar panels to 230 V AC, then AC is converted to DC by all devices.

Lost that could be fixed by making sockets with multiple AC/DC inputs and device would use DC if available without having to waste energy transforming it from AC->DC.

But that would require redesigning the all devices.. Worldwide adaptation and willingness needed.

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There are more efficient panels, and less efficient. The ones sold in greatest amounts are the ones that are typically less expensive per area per watt installed. But, as more efficient panels become less expensive; they will become more popular.

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But efficiency is not good. 15% from 1050 W/m^2 is 157 W = 157 J/s.

 

Actual power is lower than (you get ~1 kW/m^2 only if the sun is directly overhead), so the panel power is also lower. But that's not really the issue, I think. You will never get a commercial plane to fly based only on the direct solar power, even if you could get to the theoretical max efficiency of solar panels (somewhere around 30% http://en.wikipedia.org/wiki/Shockley–Queisser_limit )

 

http://www.solarimpulse.com/en/airplane/hb-sia/#.UyGRMv0fz8s

Over 24 hours, this sun energy averages out at just 250W/m². With 200m² of photovoltaic cells and a 12 % total efficiency of the propulsion chain, the plane’s motors achieve an average power of 8 HP or 6kW.

 

 

The plane was designed with huge wings and low weight so they could use wimpy motors (4 x 10hp), but there's only a factor of 2.5 improvement in efficiency they could exploit. So even at max efficiency they might generate ~20 hp, or half of what the engines use. They're relying on the batteries, and using the sunlight to extend the range somewhat. This means they could not (and did not) fly every day. They had to charge up the batteries. (I'm sure that weather payed a part. I suspect they only flew under optimal low-wind conditions, because it looks like the plane is relatively fragile)

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