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MIT says process could provide 10% of the electricity needs in America by 2050

Generating power from resources that don't create pollution is a major area of research around the world. The more power we can create from methods that have low pollution and don’t require fossil fuels, the less we as a nation will have to rely of foreign oil.

Researchers at the Department of Energy's Pacific Northwest National Laboratory (PNNL) have unveiled a new method of capturing more heat from low-temperature geothermal resources. According to the researchers, this type of geothermal resource is capable of generating pollution-free electrical energy.

The researchers are working to determine if the new method can safely and economically extract and convert heat from the geothermal resources into electricity. The ultimate goal of the project is to be able to produce electricity without generating greenhouse gas emissions and tap a currently unused underground geothermal resource.

PNNL Laboratory Fellow Pete McGrail said, "By the end of the calendar year, we plan to have a functioning bench-top prototype generating electricity. If successful, enhanced geothermal systems like this could become an important energy source."

According to an analysis conducted at MIT, the new power generating method cold produce 10% of the energy needed by the U.S. by 2050. The new process uses a special liquid that the researchers developed called a biphasic fluid. When the fluid is exposed to heat brought to the surface from water circulating through moderately hot underground rock the biphasic fluid undergoes a thermal cycling.

This thermal cycling can be harnessed to power a turbine that generates electricity. The scientists have developed a nanostructured metal-organic heat carrier called MOHCs that are able to boost the capacity of the generators to levels near that of steam cycle. The advancement was discovered while working on an unrelated project at the labs.

McGrail said, "Some novel research on nanomaterials used to capture carbon dioxide from burning fossil fuels actually led us to this discovery. Scientific breakthroughs can come from some very unintuitive connections."



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RE: Go somewhere else
By Xenoterranos on 7/17/2009 10:11:47 AM , Rating: 2
Not entirely accurate. Traditional processes use the heat to generate steam to turn turbines. This method uses a closed loop of this new fluid to spin a turbine, without converting it into steam.
The breakthrough is that this process doesn't use steam. Why that's a breakthrough, I don't know, but that's because like the rest of you, I didn't read the linked articles.


RE: Go somewhere else
By mindless1 on 7/19/2009 2:02:53 PM , Rating: 2
It probably does use steam, all they have essentially claimed may be that they are using the temperature gradient from the heated water, to heat another liquid with a lower boiling point than water OR the secondary liquid has a substantially higher coefficient of expansion without changing phase but they did write that it was bi-phase, if it remained a liquid that just expands from being heated that is only one phase in the traditional sense though if it's marketing spin they can make up nonsense to pimp their work.

This is not even close to a breakthrough, it's ages old common sense and the idea such a thing would take till 2050 is nothing more than politics or funding, not refinement of their methods.

The only real breakthrough might be they found a liquid that has an even lower boiling point than what was available previously.

I have to agree with some others, this article was too scant on info and what there was, wasn't sufficiently innovative. It shouldn't have made the cut to be posted.


RE: Go somewhere else
By foolsgambit11 on 7/20/2009 4:22:49 AM , Rating: 2
To me, the breakthrough seemed to be the heat-transfer system. It certainly wasn't the liquid. There are plenty of liquids/gases to choose from, and you could optimize the boiling point by changing the pressure in the closed-loop system.

Even then, 'breakthrough' may be a stretch. I imagine it's more of an incremental improvement created by making the nanostructure of the heat-transfer system rougher, thereby creating a larger surface area for contact.


RE: Go somewhere else
By Fritzr on 7/20/2009 4:38:42 AM , Rating: 2
Here is the relevant part of the linked article. In an H2O steam turbine system, water is biphasic--liquid & vapor.

quote:
PNNL's conversion system will take advantage of the rapid expansion and contraction capabilities of a new liquid developed by PNNL researchers called biphasic fluid. When exposed to heat brought to the surface from water circulating in moderately hot, underground rock, the thermal-cycling of the biphasic fluid will power a turbine to generate electricity.

To aid in efficiency, scientists have added nanostructured metal-organic heat carriers, or MOHCs, which boost the power generation capacity to near that of a conventional steam cycle


They say that they are using a "steam" cycle. The breakthrough was identifying a working fluid that offers almost as much efficiency as an H2O steam system. Then a turbine assembly needed to be designed to work with this new working fluid.

They are working on a demonstration unit now. Since the breakthrough is a method of using a relatively low temp heat source to drive a "steam" turbine this could be used to scavenge more power from the exhaust of conventional steam turbines as well as other "low" temp heat sources.

Just because they are focused on using it to expand the number of geothermal sites that can generate power will not prevent others from using this tech to extract power from other heat sources.


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