# Solar Power Tower Technology Using Molten Salt Storage



## mightybooboo (Feb 10, 2004)

We were just talking about this,solar power plant that runs overnight in California.
Here is a story of commercializing that tech
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http://thefraserdomain.typepad.com/energy/2008/01/solarreserve-fo.html#more

Hamilton Sundstrand, a subsidiary of United Technologies Corp. [NYSE: UTX], and US Renewables Group have formed a new entity, SolarReserve, to commercialize the concentrated solar power tower technology and corresponding molten salt storage system developed by Rocketdyne. This renewable technology will enable utility-scale solar power generation. It is designed to meet a utility's needs with a single installation capable of producing up to 500 MW of peak power.

"Due to the unique ability of the product to store the energy it captures, this system will function like a conventional hydroelectric power plant, but with several advantages. We will have the capability to store the sun's energy and release it on demand. This product is more predictable than water reserves, the supply is free and inexhaustible, and the environmental impact is essentially zero."

Solar power towers consist of a large field of sun-tracking mirrors, called heliostats, which focus solar energy on a receiver atop a centrally located tower. The energy, coming from the sun rays, concentrated at one point (the tower in the middle), produces temperatures of approx. 550Â°C to 1500Â°C. The gained thermal energy can be used for heating water or molten salt, which saves the energy for later use.
Heated water is converted to steam, which is used to drive the turbine-generator converting the thermal energy into electricity.

Lee Bailey, managing director of US Renewables Group (USRG)

The technology was originally demonstrated in conjunction with the U.S. Department of Energy at the Solar Two facility in Barstow, Calif. The unique component of the HS Rocketdyne power tower is the central receiver. This high heat flux hardware represents a unique combination of liquid rocket engine heat transfer technology and molten salt handling expertise.

From the WSJ (link only good for 7 days):

Hamilton Sundstrand's Rocketdyne segment will provide heat-resistant pumps and other equipment, as well as the expertise in handling and storing salt that has been heated to more than 1,050 degrees Fahrenheit. . . .

According to the company, molten salt loses only about 1% of its heat during a day, making it possible to store energy for long periods of time. The salt is a mixture of sodium and potassium nitrate.

From CNET:

The technology is expected to be available within three or four years. A representative said the company expects to realize revenue of more than $1 billion in the next 10 years.
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Per 'The Energy Blog' comment....

Thermal solar is currently the lowest cost solar technology, $0.08-$0.14 per kWh, for producing solar power and it is good to see another player, with hopefully some new technology, enter the field.

BooBoo <---- "It'll never Work"....Really,never.And even if it did it will cost too much.And it wont work at night,and it will only work in niche areas.And take up too much land even if it did work,which it wont!
Did I leave anything out,LOL?


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## fishhead (Jul 19, 2006)

One more thing. "We Can't!"


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## ace admirer (Oct 5, 2005)

i read it,,,,sounds like a load of rot. the salt changes phases from a solid to a liquid, takes on a bunch of btu's during the phase change,,,,thats nothing new. people were playing around with it during the late 60's. everything else yaked about in the article falls pray to the LAWS of thermodynamics. along with all the friction losses with any mechanical system.


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## Jim-mi (May 15, 2002)

NAW.......to complicated

Lets just go with the good ole bunker fuel . . . there plenty of that.


Damn . .my truck has allready seen to much liquid salt........


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## MELOC (Sep 26, 2005)

ace admirer said:


> i read it,,,,sounds like a load of rot. the salt changes phases from a solid to a liquid, takes on a bunch of btu's during the phase change,,,,thats nothing new. people were playing around with it during the late 60's. everything else yaked about in the article falls pray to the LAWS of thermodynamics. along with all the friction losses with any mechanical system.



what happens when you put it under pressure?


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## wy_white_wolf (Oct 14, 2004)

I'll reserve judgement until I here projected operating costs.

I do agree with the concept that we need to find ways to controll (make dispatchable) alternative energies, but costs must be within reason.


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## fishhead (Jul 19, 2006)

wy_white_wolf said:


> I'll reserve judgement until I here projected operating costs.
> 
> I do agree with the concept that we need to find ways to controll (make dispatchable) alternative energies, but costs must be within reason.


I agree and we need to make sure that the cost of staying the course (military, lives lost, environmental degradation, etc.) is included in the equation.


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## mightybooboo (Feb 10, 2004)

ace admirer said:


> i read it,,,,sounds like a load of rot. the salt changes phases from a solid to a liquid, takes on a bunch of btu's during the phase change,,,,thats nothing new. people were playing around with it during the late 60's. everything else yaked about in the article falls pray to the LAWS of thermodynamics. along with all the friction losses with any mechanical system.


?????????

Not to burst your bubble but they already had a plant up and running using that technology and oh,BTW,IT WORKED. 

Not speculative conjecture that the 'LAWS of thermodynamics' have somehow been breeched ,and that 'friction losses' make it unusable. Got any sources to those claims?
I'd like to see them if you do.


I'll offer this.

Ive SEEN the plant. Its real.So I'd say YES,it does work and has been proven to work. Even ran overnight.
Right up the road from me,can see it from the side of the road.

As for costs,oil can go from from 20 to 100 barrel and THAT works,but if solar is more to any degree,it doesnt work.

Why is that?


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## mightybooboo (Feb 10, 2004)

Solar One and Solar Two

Solar power towers use thousands of individual sun-tracking mirrors (called heliostats) to reflect solar energy onto a central receiver located on top of a tall tower. The receiver collects the sun's heat in a heat-transfer fluid that flows through the receiver. The U.S. Department of Energy, and a consortium of U.S. utilities and industry, built the first two large-scale, demonstration solar power towers in the desert near Barstow, California.[5]

Solar One operated successfully from 1982 to 1988, proving that power towers work efficiently to produce utility-scale power from sunlight. The Solar One plant used water/steam as the heat-transfer fluid in the receiver; this presented several problems in terms of storage and continuous turbine operation. To address these problems, Solar One was upgraded to Solar Two, which operated from 1996 to 1999. Both systems had the capacity to produce 10 MW of power.[5]

The unique feature of Solar Two was its use of molten salt to capture and store the sun's heat. The very hot salt was stored and used when needed to produce steam to drive a turbine/generator that produces electricity. The system operated smoothly through intermittent clouds and continued generating electricity long into the night.[6]

Solar Two was decommissioned in 1999, and was converted by the University of California, Davis, into an Air Cherenkov Telescope in 2001, measuring gamma rays hitting the atmosphere.


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## mightybooboo (Feb 10, 2004)

Aerial view of the Solar Two facility, showing the power tower (left) surrounded by the sun-tracking mirrors.










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BooBoo <----"It'll never Work"


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## mightybooboo (Feb 10, 2004)

Care for some Facts about thermal solar power?

http://thefraserdomain.typepad.com/energy/2005/09/about_parabolic.html

The heat collection element (HCE) is composed of a stainless steel pipe with a glass tube surrounding it, with the space between evacuated to provide low thermal losses from the pipe. The pipe is coated with a material that improves the absorption of solar energy. Several improvement have been made or developments are underway to improve performance:

* Solel has supplied all the HCE's to date. In its newest model, the UVAC 2003, they have increased the annual average performance by more than 20% over the assemblies used in the Luz plants. Absorptivity, emissivity (radiative loss) and transmittivity (of the glass) all have been improved. 
* IST's innovations include a receiver that incorporates a highly efficient blackened nickel selective surface and an anti-reflective coating on the glass envelope. The receiver pipe surface has a high absorptance for incoming light in the visible range, and a low emittance in the infrared wavelength.
* Shott Rohrgas has announced it is planning on producing HCE's and presumably will supply them for the Spanish plant. 
* The seal between the glass and the pipe has not been as reliable as desired and development of better seal materials/seal configuration is underway. 
* The HCE was connected to the stationary hot oil piping with a flexible tube in the Luz plants. Replacing the flexible tube with a ball joint will reduce the pressure drop in the hot oil piping piping by 50% and significantly reduce the parasitic power losses in the plant.

The fluid going through the receiver pipe is routed through a thermal storage system which permits the plant to keep operating for several hours after sunset while the electrical demand is still relatively high. The thermal storage system (to be used in Spain) is a two tank system in which the HTF flows through the solar field and then through a heat exchanger where it gives up a portion of its heat to heat a nitrate salt solution that is stored in a hot salt tank. The slightly cooled HTF continues on to the power generation system. At night the hot salt solution flows through the same heat exchanger heating up the HTF for generating power. The cooler oil flows from the heat exchanger to the cold storage tank where it stays until daytime when it is reheated and returned to the hot storage tank.

Several companies are involved in developing heat transfer fluid/thermal storage systems. The leading candidate appears to be a system designed by Sandia National Laboratories. Only a few details are available. The following is courtesy of Solarplaces:

* Sandia has tested a thermocline storage system that uses a single tank that is only marginally larger than one of the tanks in the two-tank system. A low-cost filler material, which is used to pack the single storage tank, acts as the primary thermal storage medium.
* Nexant has developed a near-term thermal storage option that uses biphenyl-diphenyl-oxide HTF in the solar field and then passes it through a heat ex-changer to heat molten salt in a thermal storage system.
* Kearney and Associates is investigating using a lower temperature molten salt as the HTF in the solar field as an innovative approach for reducing the cost of thermal storage for troughs.
* Work at the University of Alabama and NREL is looking into using a new class of fluids known as organic salts (or ionic liquids) as the HTF and thermal storage media in a parabolic trough plant. Organic salts have the primary advantage of being liquid at room temperatures

The Plataforma Solar de AlmerÃ­a (PSA), the European Test Center for Solar Energy Applications, in southeastern Spain is Europe's test facility for concentrating solar power development. They are developing direct steam generation technology to eliminate the thermal oil system that is currently used in solar trough plants, which would greatly simplifies the plants. The two-phase heat transfer that occurs in the receiver tube required evaluation as there are unique condition that occur in the tube. Results of testing to date indicate that the heat transfer was very sensitive to the small changes in temperature that occur in solar troughs and that their measurement accuracy was not good enough to correlate the data properly. PSA is also developing new trough collector assemblies and coatings to improve the absorption of solar energy on the receiver tubes and to decrease the reflectivity of glass.


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## mightybooboo (Feb 10, 2004)

*Hmmmmm....this one seems to be economically feasible.Built in 2006-2007.*
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*Technology*

*Nevada Solar One* uses 760 parabolic troughs (using more than 180,000 mirrors) that concentrate the sun's rays onto tubes running laterally through the troughs and containing a heat transfer fluid (solar receivers), in contrast to the power tower concentrator concept that California's original Solar One project uses. These specially coated tubes, made of glass and steel, were designed and produced by Solel Solar Systems[2] as well as by Schott Glass.[5] Motion control was supplied by Parker Hannifin, from components by Ansco Machine Company. The plant uses 18,240 of these four-meter-long tubes.

Solar thermal power plants designed for solar-only generation are ideally matched to summer noon peak loads in areas with significant cooling demands, such as the southwestern United States. Using thermal energy storage systems, solar thermal operating periods can be extended to meet even base load needs.[6] Given Nevada's land and sun resources the state has the ability to produce more than 600GW using solar thermal concentrators like those used by Nevada Solar One.[7]

Parabolic concentrators have been successfully operating in California commercially since 1984, including the largest solar power plant of any kind, the 350 MW plant Solar Energy Generating Systems. Other parabolic trough power plants being proposed are two 50MW plants in Spain (see Solar power in Spain), and a 100MW plant in Israel.[8]


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## mightybooboo (Feb 10, 2004)

Nevada Solar One









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The Real Deal....Up and Running.

BooBoo <-----"It'll never Work"


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## mightybooboo (Feb 10, 2004)

MELOC said:


> what happens when you put it under pressure?


You turn a turbine and make power


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## mightybooboo (Feb 10, 2004)

fishhead said:


> I agree and we need to make sure that the cost of staying the course (military, lives lost, environmental degradation, etc.) is included in the equation.


Shhhh.... we dont take that into account as it might be recognized for what it is, a 'hidden' subsidy to 'cheap' fossil fuels. :flame:


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## ace admirer (Oct 5, 2005)

don't get your nickers in a twist....yes it will make electricity,,,but the storage losses for the over night thing are inefficient. and the maintenance is overwhelming. you're not bursting my bubble,,,i don't have a bubble, i've been studing alternate evergy since i was 14. i know how hard it is to overthrow our unsubstainable power systems. it is not going to easy. listen i'm on your side. we have to have a clean power source. the two site photo's are nice little experiments i hope they work OVER THE LONG RUN. but the maintenance problems are pretty severe. 

go back to the basis solar energy falling of the face of the earth vs its converson to electrical energy. the numbers are not all that encouraging.


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## fishhead (Jul 19, 2006)

I brought this up one time and the other person countered with the argument that keeping dust off the system was overwhelming and would defeat they system.

How is dust controlled?


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## MELOC (Sep 26, 2005)

they need the ionic breeze, lol. uses little power, traps dust and freshens the desert air.


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## mightybooboo (Feb 10, 2004)

The solar thermal plants have been making commercial power since 1984 and are the MOST reliable power producers SCE has.And the costs are fixed.

When we had the power scam here the ONLY plants that WERENT allowed to raise rates were the solar plants,fixed costs doncha know.

This is proven technology,now they are refining it to make it even more efficient.

The Barstow Tower is paid for by DOE as an experiment to ONLY test the technology,so they did so,and proved it does indeed work,and ran them for many years. Then DOE allowed it to be turned it into a gamma ray Observatory.Solar 1 and Solar 2 are the same plant in different configurations.It wasnt closed because it didnt work,rather it was closed because it was ONLY to be used as a test bed,the plants themselves worked very well.

The other plants are 'strictly commercial' (As Frank Zappa would say),and have run flawlessly online since they have started constructing them in 1984 by Luz Industries.

The tech is simple,robust,affordable,reliable,proven and clean.

And getting better by the day as new materials are introduced and refined.


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## mightybooboo (Feb 10, 2004)

fishhead said:


> I brought this up one time and the other person countered with the argument that keeping dust off the system was overwhelming and would defeat they system.
> 
> How is dust controlled?


They are rinsed by driving a water truck by.Thats it.

I know,where will we get affordable water truck technology?


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## mightybooboo (Feb 10, 2004)

The maintenance is MINIMAL,where did you get its overwhelming? These are the most reliable power plants we have out here according to SCE,the highest online percentage of ANY plants we have.

Most reliable and overwhelming maintenance does not compute.


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## mightybooboo (Feb 10, 2004)

Storage losses are too inefficient?

Ace,are we reading the same results?

"According to the company, molten salt loses only about 1% of its heat during a day, making it possible to store energy for long periods of time. The salt is a mixture of sodium and potassium nitrate"

They are planning a plant in Australia that runs the heated transfer fluid through huge rocks and uses the heat at night to make power.

So why is whatever you get out of this free heat that is transferred into a storage source through conduction with the storage media during the day on its trip to the boiler to spin the turbine 'inefficient'?

Sorry Ace,but what you are claiming just isnt so.I think if we are going to make statements about the technology it should be backed up with some facts or truths,and I dont think you are being fair in your claims.

I think I have provided both sources and examples of the fact that is does indeed work and does so commercially in a commercial market.


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## mightybooboo (Feb 10, 2004)

ace admirer said:


> go back to the basis solar energy falling of the face of the earth vs its converson to electrical energy. the numbers are not all that encouraging.


I believe 100 square miles of Mojave Desert is enough to replace the current electrical use in the United states.

It might even have been ALL the power used in the US,I cant find my link.

Whatever it was,its a LOT of power,and it CAN be converted in an economical fashion,its being done NOW.

And No,I dont propose to use solar thermal as our only power to the grid.Nor does anyone else.


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## mightybooboo (Feb 10, 2004)

Seems like they are building quite a few of them.Must be a reason.
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http://en.wikipedia.org/wiki/List_of_solar_thermal_power_stations 

* This is a list of power stations that are based on Solar thermal energy technology.
* Most of the CSP plants of the world can be found on Google Earth : kmz file

PS10 solar power tower, Spain Seville, 11MW, power tower design










Solar Energy Generating Systems, USA Mojave desert California, total of 354MW from the 9 plants, parabolic trough design.1 of NINE operational SEGS plants in SoCal Mojave Desert.











* 1 Operational
* 2 Under construction
* 3 Announced
* 4 Out of commission
* 5 See also
* 6 References

[edit] Operational

* Solar Energy Generating Systems, USA Mojave desert California, total of 354MW from 9 sites, parabolic trough design
* Nevada Solar One, USA Nevada, 64MW, parabolic trough design
* Liddell Power Station, Australia, 95MW heat, 35MW electrical equivalent as steam input for conventional power station, Fresnel reflector design[1]
* PS10 solar power tower, Spain Seville, 11MW, power tower design

[edit] Under construction

* Andasol 1 solar power station, Spain, 50MW with heat storage, parabolic trough design
* Andasol 2 solar power station, Spain, 50MW with heat storage, parabolic trough design
* Solar Tres Power Tower, Spain, 15MW with heat storage, power tower design

[edit] Announced

* Mojave Solar Park, USA California, 553MW, parabolic trough design[2]
* Pisgah, USA California near Pisgah north of I-40, 500MW, dish design[3]
* Ivanpah Solar, USA California, 400MW, power tower design[4]
* Unnamed, USA Florida, 300MW, Fresnel reflector design[5]
* Imperial Valley, USA California, 300MW, dish design[6]
* Negev Desert, Israel, 250MW, design will be known after tender[7]
* Carrizo Energy Solar Farm, USA California near San Luis Obispo, 177MW, Fresnel reflector design[8]
* Uppington, South Africa, 100MW, power tower design[9]
* Shams, Abu Dhabi Madinat Zayad, 100MW, parabolic through design[10]
* Yazd Plant, Iran, 67MW steam input for hybrid gas plant, technology unknown.[11]
* Barstow, USA California, 59MW with heat storage and back-up, parabolic trough design[12]
* Victorville 2 Hybrid Power Project, 50MW steam input for hybrid gas plant, parabolic trough design[13]
* Kuraymat Plant, Egypt, 40MW steam input for a gas powered plant, parabolic trough design[14][15]
* Beni Mathar Plant, Morocco, 30MW steam input for a gas powered plant, technology unknown[16]
* Hassi R'mel, Algeria, 25MW steam input for gas powered plant, parabolic trough design[17]
* Cloncurry solar power station, Australia, 10MW with heat storage, power tower design[18]

Note, that for the dish announcements a test site with 40 dishes producing 1MW would be constructed near Pisgah in 2007.[19] Actual construction or progress of this test site could not be found on the internet or obtained by other means.[20]

The Victorville 2 Hybrid Power Project, Ivanpah Solar and Carrizo Energy Solar Farm has reached the stage of an Application for Certification (AFC) with the California Energy Commission.[13]

[edit] Out of commission

* Solar One, USA California, 10MW, power tower design
* Themis (under rehabilitation), France, 2MW, power tower design


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## ace admirer (Oct 5, 2005)

the plant in the second photo was not running when the photo was taken,,,,,the three little cooling towers are not running..so the turbine cannot be running..but anyway i hope it works out,,,,all energy is solar and the more direct we get to it the better off we will be.


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## mightybooboo (Feb 10, 2004)

Yes,that is a construction photo.

The troughs concentrate the solar energy onto the heat tubes by a factor of 80.You tube Video of the plant and explanation (simple explanation) on how it works
http://video.aol.com/video-detail/nevada-solar-one-solar-power-station/1315460152


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https://ideotrope.org/index.pl?node_id=66919

Regulations in Nevada requiring a certain percentage of the state's energy portfolio come from renewable sources has resulted in the construction of Nevada Solar One, a 64MW concentrated solar power plant. 350 acres of linear parabolic reflectors are used to heat a high heat capacity fluid in black steel pipes (enclosed within a vacuum jacket made of glass!) running along the focal line, to 750Â°F, and this fluid is then used to generate steam, which turns a turbine, generating electricity. The hot fluid can be stored in large insulated tanks for use in generating power when the sun is not up. The projected wholesale price of the power generated by the plant is 7-10 cents per kWh, which is competitive in many regions of the US, according to recent data from the EIA. Similar solar concentration power plants built in the 80s as a result of Jimmy Carter's forward looking energy policies have operated reliably for 25 years with little degradation. Nevada Solar One was cheaper per unit power to build, and is more efficient. It was built in approximately one year, at a cost of $240,000,000, and went on line this spring (2007). Alas, almost all of the companies involved are European (German, Spanish, Swedish). The idea is in many ways low-tech, but the results are very promising. There are supposedly enough suitable installation sites in Nevada to generate 600GW of power (30x more power than Nevada currently consumes).


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## mightybooboo (Feb 10, 2004)

ace admirer said:


> go back to the basis solar energy falling of the face of the earth vs its converson to electrical energy. the numbers are not all that encouraging.


The troughs concentrate the solar energy on the heat pipes by a factor of 80


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## mightybooboo (Feb 10, 2004)

ace admirer said:


> the two site photo's are nice little experiments i hope they work OVER THE LONG RUN. but the maintenance problems are pretty severe.


SEGS has been running since the mid 1980's with a 98% reliability.

They have sold 1.6 Billion Dollars of electricity as of 2006 I believe it is,uncertain on the actual date so wont swear its 2006.Ive seen other sources claiming 800 million in 1996 alone.

After they have paid off the capital costs of the construction they produce power in the 2-3 cent per kilowatt range.


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## fishhead (Jul 19, 2006)

Is there any benefit to concentrating the suns energy with a magnifying glass of sorts?

Is that what the troughs do?


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## mightybooboo (Feb 10, 2004)

fishhead said:


> Is there any benefit to concentrating the suns energy with a magnifying glass of sorts?
> 
> Is that what the troughs do?


Yup,thats just what the troughs do.
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This is a pretty cool site Fishhead,you might really enjoy it.
http://www.seao2.com/solarsphere/csp.htm
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Concentrating Solar Power

Concentrating solar power (CSP) is a form of energy production technology that concentrates large amounts of solar energy onto a small area. Here, the energy density is much higher than that available from just beam sunshine and the efficiencies of its conversion to useful energy (ie electricity or steam) is much higher.

There are three main types of CSP including direct intercept dishes, solar troughs and solar towers. Some newcomers to the field include, for example, the Compact Linear Freznel Reflectors. Solarsphere technology combines elements of direct intercept dishes with solar towers and does this with a design philosophy and materials that potentially permit the units to be produced large and inexpensively.


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## mightybooboo (Feb 10, 2004)

mightybooboo said:


> They are rinsed by driving a water truck by.Thats it.
> 
> I know,where will we get affordable water truck technology?


'Insurmountable' solar trough dust cleaning problem.....


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