Generating electricity

[MatthewBrum]

But as far as generating electricity I would think you do not have enough of a temperature different to drive a turbine or piston type engine

[island911]

Originally Posted by turbo6bar

... Solar water heating should receive greater focus in America. It's proven, efficient, and can immediately reduce energy usage, particularly in the sunny Southern US.

Yep. That's where the low hanging fruit is.

But, why listen to engineers, when fantasy greeners are pitching better intent.

[RWebb]

"I will ask the experts"

you know, I think you should ask your local utility. They will likely tell you 'noo' as per above posts, but at least that will indicate some interest in this for them to log into their files...

In 10, maybe even 5 years, it could be a go.

[turbo6bar]

Originally Posted by RWebb

In 10, maybe even 5 years, it could be a go.

Nobody accused you of being ridiculously optimistic, lately?

cel, checking vapor pressure chart for propane, there is no way you're going to condense the propane. Propane boils above -44 degrees F. Instead of a piston engine, you could use an air-driven pump (sort of like a air grinder or polisher, except much larger). At ground temp of 60 degrees, propane would be 90 psi. Your solar panels would heat to at least 110 degrees, giving you over 200 psi. Use that pressure differential to move the air-pump.

I still think you're looney, but you are thinking outside the box.

[RWebb]

Originally Posted by turbo6bar

Nobody accused you of being ridiculously optimistic, lately?

PV cells are chips - and not even highly complex ones - it is the conversion & power handling that are the issues here. You can look at the rates of progress in "computer" chips for an inkling of what will happen.

Add in the same subsidies that oil & coal get are you there even sooner.

[Heel n Toe]

Originally Posted by cel

Not being very knowledgeable in the subject I will ask the experts. Would it be economically feasible to generate enough electricity for a small house in the Houston area using the earth as a heat sink and solar panels as a heat source with propane as the transfer medium. A piston type motor would drive the generator.

You should probably contact David Heymann... if he knew how to do this...

http://www.snopes.com/politics/bush/house.asp

...me might know how to make your idea happen.

[red-beard]

The answer is yes, but you would want to use a Sterling cycle, not a brayton or otto cycle which require compression. The "problem" is that the temperature difference is not great in Houston between your source and sink, so your collector and sink would need to be huge.

[cgarr]

Never could figure out the old Sterling Fan I have, you use heat to keep you cool??

[island911]

But does it cycle?

[jyl]

PV cells are made from silicon ingots similar to other semiconductors, although lower quality. Only a few companies make the ingots, and they were slow to invest the hundreds of millions required to increase production. For the past few years, supply has been tight and this has supported the price of PV cells. Supply is now coming online and silicon wafer prices are falling steeply. As are PV prices. The other big cost in PV manufacture is the capital equipment, which is something like a semiconductor fab though simpler. Here too supply is increasing, as fabs become obsolete they or the equipment in them can be repurposed for PV cell production. I expect PV prices will fall by 50 pct in a few years. With even modest efficiency increases, the PV cell portion of a PV system's cost should decline, in $/watt terms, by over half in the next few years. Installation and inverter costs are slower to fall, but there are lots of under-employed residential construction workers out there.

[red-beard]

Originally Posted by jyl

PV cells are made from silicon ingots similar to other semiconductors, although lower quality. Only a few companies make the ingots, and they were slow to invest the hundreds of millions required to increase production. For the past few years, supply has been tight and this has supported the price of PV cells. Supply is now coming online and silicon wafer prices are falling steeply. As are PV prices. The other big cost in PV manufacture is the capital equipment, which is something like a semiconductor fab though simpler. Here too supply is increasing, as fabs become obsolete they or the equipment in them can be repurposed for PV cell production. I expect PV prices will fall by 50 pct in a few years. With even modest efficiency increases, the PV cell portion of a PV system's cost should decline, in $/watt terms, by over half in the next few years. Installation and inverter costs are slower to fall, but there are lots of under-employed residential construction workers out there.

$1.70 per watt, FOB Shanghai, is what I've been quoted, recently. I'm working with some people on reducing the cost of the inverter, by about 50%, and make it more efficient in the process. I expect that PV is going to be cost effective shortly.