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Solar heating Idea

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infobomber:
I'm just going to start a new topic here

First, as most of us know you can get 100% of your hot water in summer from solar heat.

Now, In winter you dint want your water to freeze, so something you can do is instead of solar heating water in the winter, is solar heating antifreeze. have a coil of hose in some water and circulate the heated antifreeze through it.  Obviously you want to avoid contamination of the water. 

I had an interesting idea tonight. So my folks have a large house, the heating system is hot water run to radiators and powered by a diesel furnace. This also heats the tap water. 

So the idea was, instead of heating the water with diesel, using solar heated water/antifreeze and cycling it thought a similar system. 

Just an idea, I know there are plenty of ways to use solar heat. 

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To expand on this you could also use any sort of fuel to heat the water and run it through the system.  You could make a wood fired unit for example to do the same thing.  Idk about potability, but cold water could be on a separate circuit. 


“Mark”:
Another idea is to put your solar hot water heater inside your house. If you have a large window that gets full sun, you could put your heater in that room on the wall opposite the window. This will work far better in the winter. You could also use just a simple water tank, painted black. As an added bonus, it will also work to radiate heat in the night.

infobomber:

--- Quote from: Mark Rose on May 21, 2009, 09:51:00 AM ---Another idea is to put your solar hot water heater inside your house. If you have a large window that gets full sun, you could put your heater in that room on the wall opposite the window. This will work far better in the winter. You could also use just a simple water tank, painted black. As an added bonus, it will also work to radiate heat in the night.

--- End quote ---

Good on ya!

Useing a large (possibly wall sized) water tank as a thermal mass in a passive solar setup.  Also I was pondering in another thread about using a solar oven to vaporize water to create steam energy.  Now suppose we combine this to where a section of the internal solar thermal mass is compartmentalized and will vaporize the water, this could make possible the use of steam for heat and power generation (in theory of course).   

“Mark”:

--- Quote from: infobomber on May 22, 2009, 10:26:00 AM ---Good on ya!

Useing a large (possibly wall sized) water tank as a thermal mass in a passive solar setup.  Also I was pondering in another thread about using a solar oven to vaporize water to create steam energy.  Now suppose we combine this to where a section of the internal solar thermal mass is compartmentalized and will vaporize the water, this could make possible the use of steam for heat and power generation (in theory of course).   

--- End quote ---

The only thing you have to worry about are leaks and making sure your structure can support the weight of the water (1 kg/l, or about 8.3 lbs/gal).

I'm not too sure how much power you'd get of boiling water with sun. You get about 300 w/m2, and the black body radiation of the water would dissipate a good deal of that. I suppose if you use some parabolic mirrors to concentrate the energy on one spot you could create more steam/pressure to drive a turbine.

It takes about 332kj to raise 1 liter of water from room temperature to boiling. So if we're getting 300 watts of energy from the sun per square meter, it would take 2 minutes to raise that water to boiling. The phase transition from liquid to vapor takes 2272 kJ/l, so it would take an additional 13 minutes to boil the water off. So if we were able to use all the energy from sunlight in one square meter, we could boil off about 4 liters of water per hour. Steam turbines are less than 50% efficient, so you would be able to get less 150 watts of power per square meter of collector tops. You could also recycle your steam using cooling towers and increase your efficiency quite a bit; though you'd have to make them pretty big to avoid any back pressure against the turbine. You would also have to deal with corrosion over time, too, but it's certainly possible -- and probably more expensive than going with solar panels.

LGM30:
Instead of a turbine consider a different process...
There are solar stirling engines in use.
http://news.cnet.com/Dishing-out-power-with-a-solar-engine/2100-1008_3-6129168.html

Google stirling engine for the theory behind the stirling engine. They were invented in the 1800's and used wood or coal fired heat as the motive source.  Recently companies have started applying parabolic mirrors to concentrate the sun's energy and drive the stirling engine.

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