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Author Topic: solar heat to electric  (Read 18276 times)

nickle989

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Re: solar heat to electric
« Reply #15 on: February 14, 2009, 03:52:01 PM »
I would have to completely disagree with only a 9% conversion ... that crap is for accademics caught in books and the four walled institutes .. no offence.  But lets just take 9% .. it is still a fraction of the cost to use solar heat conversion then it is to buy the PV panels from the thieves.

For the last few months I have been converting to solar heating.  It has taken some time as the off the shelf products do not transfer heat very well.  I live in central Canada.  On a -25 celcius day I have 234 celcius on the inside of the evacuated heat tube and 134 celcius on the heat exchanger exposed to the -25 degrees.  It takes under 2 minutes from a dead start exposure to reach over 100 degrees.Depending on the load that I put on I can raise or lower the heat exchanger.  A 1200 gallon water tank will be acting as a thermal mass.

I have University prof's come down and see and they can't believe what I am doing!  I will post some pics and videos much later as I need to finish my stirling engine.

I will be using a stirling engine to convert excess heat to electricity.  However it will be a sealed unit.  The sun has around 1300 plus watts per square meter.  In a sealed stirling unit one can use various gases that will get you a much higher rate of energy transfer.

Here is an older pic from an unrefined exchanger.
« Last Edit: February 14, 2009, 04:17:26 PM by nickle989 »

jadaro2600

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Re: solar heat to electric
« Reply #16 on: February 23, 2009, 01:45:37 AM »
The sun is good for heat - very good, and one of the primary uses of electricity in a home is the hot water heater.  Supplementing a good home with a solar heat exchanger can be effective at lowering the cost / or should I say / decreasing the net use of electricity.

A solar heat exchanger with a solar powered pump may be the first step in switching to solar.  As far as powering your air conditioner though - it's going to require some serious wattage.

nickle989

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Re: solar heat to electric
« Reply #17 on: February 23, 2009, 03:00:39 AM »
I would not say serious wattage ... an average central air uses around 4800 watts ... what is needed though is a good way to transfer the suns energy to electricity.

Mark69

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Re: solar heat to electric
« Reply #18 on: February 23, 2009, 03:37:02 PM »
@nickle,

I look forward to reading your posts on your home setup.  It would be great as well when you have it all running if you could make instructions on how we can duplicate your setup.  It is amazing you get such heat differences when starting at -25C!

Mark

buzneg

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Re: solar heat to electric
« Reply #19 on: March 01, 2009, 06:00:57 AM »
wow after reading some stuff I guess 10% is a reasonable number for solar thermal efficiency. The problem is light diffusion even on a clear day is 10%. Consentraitors can't make use of diffused light reflecting off the coulds where PV can. Also I read the heat collector diffuses IR 8%, and the black is 94% absorbive. When you add all this up, plus the few percent lost in the mirror it comes down to about 10%, but maybe 15%. Assuming the turbine is 50% efficient. Though, that being said solar thermal is still way cheaper then regular PV, and cheaper then wind, infact it's still near coal's build cost. The industry is saying Solar thermal is $3000 per kW capacity, but I would guess that they  averagly run at 10%-30% capacity??? Anyways with my figures it's still much cheaper then this, they use expensive mirrors or lenses, and it's still a new technology.

http://www.theoildrum.com/node/3791

nickle989

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Re: solar heat to electric
« Reply #20 on: March 01, 2009, 12:33:15 PM »
On an overcast - cloudy day in -15 c the solar tube reaches and maintains 38 to 42 c throughout the day.  The tubes are very efficient in collecting the sun's energy of both visable and non-visable light and consentrating it on the inner surfaces.  With light being diffused by the atmosphere does not affect the collector that greatly to make it unusable in the practicle sense. 

$3000.00 per kw is very high for solar thermal ... those folks should go back and do some first grade math.  Each panel of mine has a cost of 750.00 with mods and produces well over 800 watts consistantly on a cloudy day.  Sunny day's are up around 1200 watts.  Storing that energy in a thermal tank to run through the night will be done by a 1200 gallon water tank in ground and insualted. 

The sun in free energy and so is the wind ... just harvest it. 


buzneg

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Re: solar heat to electric
« Reply #21 on: March 01, 2009, 08:30:02 PM »
On an overcast - cloudy day in -15 c the solar tube reaches and maintains 38 to 42 c throughout the day.  The tubes are very efficient in collecting the sun's energy of both visable and non-visable light and consentrating it on the inner surfaces.  With light being diffused by the atmosphere does not affect the collector that greatly to make it unusable in the practicle sense. 

$3000.00 per kw is very high for solar thermal ... those folks should go back and do some first grade math.  Each panel of mine has a cost of 750.00 with mods and produces well over 800 watts consistantly on a cloudy day.  Sunny day's are up around 1200 watts.  Storing that energy in a thermal tank to run through the night will be done by a 1200 gallon water tank in ground and insualted. 

The sun in free energy and so is the wind ... just harvest it. 



well you doing just open vaccum tubes right? They will make use of the diffused light, concentraitors can't make much use of the diffused light though. But the diffused light energy is probably much less then the direct light energy, what I want to find out is by how much.