Solar Power Minus the Light 439
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?"
Celsius (Score:0, Informative)
Carnot efficiency. (Score:5, Informative)
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.
Solar powered Air conditioning (Score:5, Informative)
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 [wikipedia.org]
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.
Re:Just use solar already... (Score:3, Informative)
Re:Thermo (Score:4, Informative)
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.
Deep in the earth... well not that deep. (Score:4, Informative)
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.
Re:Only solves 50% of the problem (Score:5, Informative)
Wow, that would be expensive. Here (germany) you get 2kW (10x200W) for 9000 EUR [energetik.de]
Next time please don't pull prices out of your ass.
Reichstag, Berlin (Score:3, Informative)
The day came 100 years ago (Score:3, Informative)
no, it solves 100%, it clearly states ambient air (Score:5, Informative)
cooling water needed (Score:2, Informative)
No perpetual motion or violation of the laws of thermodynamics involved,"
Yes, perpetual motion or violation of the laws of thermodynamics involved. Plus, if you look at their website, that's not what they are claiming.
If you put the steam through the turbine, you now have lots of low-pressure steam that you can't get any more useful work out of. They are condensing the steam back into liquid using copious amounts of cooling water (see the condenser and motorless pump in their animation). You don't get energy for nothing.
Also, keep in mind that the article summary is a little misleading by mentioning that the liquid boils around 58F. They are actually heating the system up to 150F - they are _not_ running this at room temperature. They are simply arguing that it's easier to get 150F temperatures from natural sources (geothermal, solar) than the higher temperatures required for more traditional steam engines.
Re:You already have thermal energy (Score:2, Informative)
Solar-powered air conditioning, using no electrical conversion at all... brilliant.
You're not using your head (Score:1, Informative)
DC always has a month of weather than is 90-100 degrees with 80-100% humidity. Makes you wonder why we were stupid enough to build a city here.
And in Pennsylvania we always had 1 week fo 105-110 degree weather (accompanied by 4 weeks in january/february of 0 degree weather.
This is not a symptom of anything other than brutal weather in eastern US.
Re:You already have thermal energy (Score:1, Informative)
An very old, now deceased, friend of mine used to tell me they would bury a six-pack in sand, pour fuel on it, and light the fuel, during WWII. The beer would then be cool enough to drink(for Americans who like cool beer). This always sounded a bit nutty to me, but I guess it worked.
If you try this and it works, make a toast to Carmine Mangano!
sure it will, it's not 10PSI (Score:4, Informative)
Re:Just use solar already... (Score:5, Informative)
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.
The wonders of popular science? (Score:2, Informative)
The energy which needs to be absorbed for turning a liquid into gas can be X. A turbine cannot utilize all energy because of friction, slowness etc. So the energy which the turbine produces would be X - delta X, which could be Y.
Then you'd like to use that energy Y to power air condition to lower the temperature inside?
Did it ever strike these people to think about something called "Solar Photovoltaic Panels", commonly named "Solar Panels", the efficiency of using the photovoltaic effect is indeed much higher than relying on heating a liquid.
Anyone even slightly familiar with thermodynamics and physics will tell you that a large part of the energy to heat up a liquid into a gaseous phase will be lost to the enviroment (owning to the rather amazing "Second Law of Thermodynamics"!).
To summarize, heating a liquid into steam to harvest energy, and then attempt to convert the energy into electric energy, INSTEAD of putting up a solar panel array... Is a fantastically stupid idea. It doesn't matter that the liquid has a lower boiling point, what that means is that less energy has to be absorbed for it to leap into a gaseous phase. In plain english, by using such a liquid you collect less energy than if you were to use good old water.
Also, lets not get into the whole aspect of the fact that the boiling point of a liquid is not only dependent on temperature, but pressure as well... No matter how you twist and turn, you end up with X energy and you will loose energy in every single step and conversion.
Solar Photovoltaic Panel is much more efficient, in every possible way you look at it.
This whole idea reminds me of when you're a kid and you try to lift yourself off the ground by pulling your own legs hehe....
Re:Just use solar already... (Score:1, Informative)
Re:Only solves 50% of the problem (Score:3, Informative)
Re:You already have thermal energy (Score:3, Informative)
Re:Only solves 50% of the problem (Score:2, Informative)
The OP said it would cost 1000AU. So "Next time please don't pull prices out of your ass" feels a bit harsh - and who's to say that panels aren't cheaper in Europe?
Re:our galactic stone-age (Score:3, Informative)
wait for it
Canada.
Re:More flies in the ointment ... (Score:3, Informative)
This one is not a big deal because R-22 can almost always be replaced one of the common modern refrigerants (I'm not sure which offhand, might be R-409c), which has extremely similar properties and is often used to replace R-22 in old air conditioning units. It's a little bit less efficient though (and most equipment can be redesigned to use more modern chemicals that work better). I have no idea why they used R-22 here.
Your other points are more significant problems.
(Incidentally, R-22 [wikipedia.org] is an HCFC but not a CFC, and is not a major threat to the ozone layer, you're thinking of the banned R-12 which was both a CFC and a major issue. However, R-22 is being phased out anyway because there are better choices available which are even less harmful and no particularly compelling reasons to use R-22 any more)