DIY solar cells, about 2 bucks a watt:

Originally posted by sonhouse
http://greenpowerscience.com/

They have a youtube video showing the process. It's tedious but you can get your solar panels for less than half price DIY.

brilliant, you can buy a kit from ebay for £46.00, my only reservation is how one would mount them and protect them. i thought of a double glazing unit and try to seal it with silicone sealant after the solar panels are inserted, what do you think?

Originally posted by robbie carrobie
brilliant, you can buy a kit from ebay for £46.00, my only reservation is how one would mount them and protect them. i thought of a double glazing unit and try to seal it with silicone sealant after the solar panels are inserted, what do you think?

Did you watch his video, with his wife? He mentioned several alternatives, sealing with epoxy being one. It would have to be UV stabilized though otherwise it would only take one summer to ruin and crack the epoxy.

They need to be protected for sure, they are as brittle as a tostada chip.

I can see a better way to solder the power line though. He uses a run of the mill soldering iron but I have lots of experience with electronics and there is a kind of soldering tip that is a long line to desolder IC leads, you press it down more like a cow getting a branding, solders a long strip all at once.

This could be the basis for a business, making the cells then adding a 50 percent profit and reselling them. The idea of it as a business would depend on how fast you can solder them together and how careful you are not to break them.

You need to make an assembly line out of them, for home use or business since you would need hundreds or thousands of them for a real system.

100 of them would be 200 watts max, probably a lot less in reality.

So you would need 1000 or 2000 of them to power a home. Not sure what the size of each cell is, looks like a 3X5 inch postcard. 15 square inches, ten or so to make a square foot. If so, 20 watts max out of an incipient light input of something like 75 watts on the ground max (the light energy hitting the TOP of the atmosphere is around 125 watts per square foot, which is why orbiting satellites generate a lot more energy pound for pound than Earth bound version, they get at least 2X the energy input)

Those cells he showed would probably max out at around 10 percent efficiency, if it was higher than that, it would be all gravy means if you got say 10 watts per square foot into the power meter, 1000 watts would need an area of 100 square feet, or 10 by 10 foot square or 5 by 20 feet. So 2000 watts would need about 10 by 20 feet. But if it generates 2000 watts during daylight hours, since the peak power time of the day is only about 1/3 of the total time for power collection so that would be only about 700 watts spread out over 24 hours. That means if you want 2000 watts 24 hours a day average, you need a cell system generating more like 6000 watts during the day, 4000 watts going into some kind of energy storage, whether battery, compressed air, mechanical rotor, pumping water uphill and using it with a small generator at night, whatever you use to store the energy, then you use the 4000 watts of stored energy to run the house at night till the next cycle of light.

Of course if you have a week long rainstorm you are screwed.

A better way to store energy is to feed power back into the power grid, your watt/hour meter runs backwards, they actually pay you for the electricity you make, then if there is a week-long storm, you are covered. Illegal in some places however, legal here in Pennsylvania.

Originally posted by googlefudge
Frankly for most places solar electric is so costly and inefficient that your better off going with solar thermal... If you can store large amounts of water then using the suns energy to heat it and then store that heat will likely save you far more on heating/total energy usage than photovoltaics.

of course it all depends on your own personal situation, and location. But photovoltaics tend to be poor on the cost benefit ratio.

You have a major point there. However, newer PC designs collect both heat and electricity so that may not be such a deterrent in the future.

I know for me, our house has a burner running around 200,000 BTU/hr, if you divide that by three thousand, you get the amount of kw it would take to do that job with electricity, about 70 Kw to heat our house. To do that with total solar would take more room than I have in my 1/3 acre, the whole thing would have to be paved with solar heat and electrical cells to get that much energy.

The answer to that is to get the very best insulation you can muster, which saves energy in the winter AND summer.

That is the real answer, reducing the energy required for a house by super insulating it.

In my case, nobody can get at the home that kind of electric service, 220 volts at over 300 amps, most houses have only 100 amp service, maximum maybe 15 Kw at once. 200 amps at 220 would still be only a bit over 40 Kw/hr.

Even if you had 300 amp/220 volt service using 70 Kw, that comes out to over 100 dollars per day to heat your house electrically. Not gonna happen. You could have 3000 dollar monthly heating bills in the winter at that rate.

Originally posted by sonhouse
I know for me, our house has a burner running around 200,000 BTU/hr

Is that gas? How does the cost compare to electricity? You say electricity would be USD100 a day, what would gas (or whatever you use) cost?

My mum used to get cheap solar cells and sell them on to people in the rural areas where there is no electricity where they use them to power radios (while the sun shines). It saves a small fortune on batteries.

Originally posted by sonhouse
You have a major point there. However, newer PC designs collect both heat and electricity so that may not be such a deterrent in the future.

I know for me, our house has a burner running around 200,000 BTU/hr, if you divide that by three thousand, you get the amount of kw it would take to do that job with electricity, about 70 Kw to heat our house. To d ...[text shortened]... . Not gonna happen. You could have 3000 dollar monthly heating bills in the winter at that rate.

Where do you live that you need 200,000BTU/hr heating, constantly?

given that its possible to provide most/all the hot water/heating for a reasonable size (well insulated) family home in parts of the UK with solar
thermal...

where its not especially noted for being warm and sunny, I have to wonder where you need a constant 70KW heating power,

given a spec heat cap of water of 4.2 J/gK that would heat 1/3 ltr per second by 50 deg C. or 20ltrs per minute, given a power shower uses

around 16 ltrs per minute, for short bursts. and Central heating should not need to be on for most of the day,

the average energy cost should be much much lower than that.

There are of course some places that wouldn't benefit from solar thermal... but they wouldn't benefit from photovoltaic's either.

You are of course completely right about insulation, another good one is that we waste vast amounts of drinking water flushing loo's and

such, much better to have a dual water system that stores and uses rain water for non drinking water uses.

Originally posted by googlefudge
Where do you live that you need 200,000BTU/hr heating, constantly?

given that its possible to provide most/all the hot water/heating for a reasonable size (well insulated) family home in parts of the UK with solar
thermal...

where its not especially noted for being warm and sunny, I have to wonder where you need a constant 70KW heating power,
...[text shortened]... ter to have a dual water system that stores and uses rain water for non drinking water uses.

I live in north of philadelphia about 100 km. The winters here can get down to zero F and below, plus my house was built in 1880 and was not insulated. We insulated it as best we could and the heating bill cut almost in half but it is a three story 4500 square foot house, 7 bedrooms, 2 baths. It's pretty big! Of course it doesn't run 200K btu continuously, the duty cycle is probably around 50 percent, making it more like 100K btu or around 35 Kw running 24 hours a day if it was electric.

I was just looking at a rainwater collection system, some of them are pretty elaborate. Also looking at gray water flushing, taking shower, bath, and clothes washer dumps and feeding that back into the toilets. I hear that can reduce water consumption alone by 30 percent. Our water bills average about 500 bucks for three months, 2000 bucks a year for terrible water. We have to filter it just to be able to stand drinking it, they chlorinate the hell out of it and it is pretty hard.

It is the highest price for water almost anywhere in Pennsylvania. Oh, the taxes are about 5000 bucks a year for our house which is valued at around $130,000 also. Pretty bad all the way round.

If I had known how bad this town was when I first came to Pa, I never would have moved here but now it's too late, can't get out of here now.