Showing posts with label parabolic. Show all posts
Showing posts with label parabolic. Show all posts

Thursday, July 2, 2009

Saharan Mega Solar

It is nice to see something this brave been drummed. Of course, the method lends itself to incremental build out in accelerating stages allowing the financial supporters to not be strained.

So it is nice to talk about half a trillion dollars but you start with a hundred million plant and establish the entire key infrastructure. All that power must make it into Europe. This is not dissimilar to the James Bay power development which presently supplies the North East.

Again doubling it up every few years and you get there amazingly quickly.

Parabolic mirrors and a heat reception pipe at the focus have been obvious from day one. The main trick is to make sure that the hot spots do not get too hot. Then the working fluid must be efficient and we are comfortable with water. The pipe will have to sustain high pressure since it is necessary to produce high grade steam.

We certainly do not need Bedouin sharpshooters.

While we are at it, the devices will provide a huge amount of ground cover and substantial shade. Many plants prosper in such conditions and providing ground cover opens the door for fauna. All of that can capture and hold the little rain that does fall. Maybe we can slowly begin the restoration of the Saharan ecosystem.

Europe eyes giant desert solar power plant

http://www.solardaily.com/reports/Europe_eyes_giant_desert_solar_power_plant_999.html

by Staff Writers
Berlin (UPI) Jun 26, 2009

As the world's reserves of hydrocarbon fuels dwindle, a German-led consortium is pushing ahead with a revolutionary plan to build a giant thermal solar power plan in the North African desert that would provide up to 15 percent of
Europe's electricity needs.

The ambitious project, known as Desertec, is expected to cost $555.3 billion. It would generate inexhaustible and affordable quantities of energy across the Mediterranean -- and even on a global scale if necessary.

One of its big attractions is that it would emit no
carbon dioxide in the process. If Desertec ever gets off the ground it would be the largest green-energy project on the planet.

In theory, a global system of solar thermal power would also eliminate the prospect of resources wars erupting in the years ahead as the planet's natural resources that currently produce energy -- oil, gas and coal -- disappear.

The plan, which has been kicking around for years, got a big boost on June 17 when a group of 20 companies, including Siemens, Deutsche Bank, European energy giant E.On and insurance major Munich Re, announced they will launch the initiative at a meeting on July 13 and consolidate the consortium.

Munich Re Director Torsten Jeworrek said the consortium aims to "present concrete plans in two or three years" and start producing commercial quantities of power within a decade, freeing energy-hungry Europe from its dependence on oil, natural gas and coal.

The idea for this massive project to harness the sun's energy on a grand scale originated with a group of European scientists and politicians called the Trans-Mediterranean Renewable Energy Cooperation.

The concept of large-scale solar power has been around for some time but was never able to make the breakthrough because of cheap oil.

Those days disappeared, probably forever, a few years ago when the price oil soared to nearly $150 a barrel. In recent months it plunged back to $40 and his since crept back up to around $70. But that is still double the level it was only five or six years ago.

"No energy source even comes close to achieving the same massive energy density as sunshine," observed Hans Muller-Steinhagen, who has been commissioned by Germany's
Environment Ministry to investigate the feasibility of Desertec. He thinks it's a "real possibility."

The technology is already available, according to Muller-Steinhagen. Solar power plants have been operating, without problems, in California and Nevada since the mid-1980s.

Solar plants are now being built in southern Spain, and construction has started on similar plants, on a scale infinitely smaller than that envisioned for Desertec, in
Algeria, Morocco and the United Arab Emirates.

Desertec, according to its advocates, will be distinctly low-tech and won't require nuclear reactors or CO2-emitting coal-fired power plants.

The sun's energy would be collected in huge arrays of curved mirrors known as "parabolic trough collectors." They would heat water, which generates steam that drives turbines that produce electricity.

Muller-Steinhagen estimates that a huge complex of these mirrors across an area the size of Austria in the vast empty desert could produce enough energy to meet the entire global demand. An area one-quarter that size would be enough to power all of Europe.

Every year the sun produces 630,000 terawatt hours of energy in the Maghreb, the Arabic name for North Africa, that is untapped. Europe consumes just 4,000 terawatt hours of energy a year. That's only 0.6 percent of the unused energy that falls on the North African desert.

Solar energy can also be harnessed even in the hours of darkness, experts say.
Heat produced during the day can be stored in tanks of molten salt, allowing the Desertec turbines to produce electricity even when the sun's not shining.

For the North African states -- Libya, Morocco, Tunisia, Algeria and Egypt -- Desertec would be of immense economic benefit. It would not only produce cheap energy for the region but create jobs and industrial opportunities that would attract investment.

Wednesday, June 10, 2009

Thermal Solar Working Fluids

This is a bit of a puff piece, but a little digging sheds light on the working fluid now been used for solar thermal applications. Go to the second item to grab some specifications.


Parabolic mirrors concentrate a lot of energy over the cross section of the energy collector and the intent is to drive the temperature as high as is safe. That means that the working fluid is the primary design constraint. These fluids go to 300 C plus and remain fluid under the temperature of boiling water.

That suggests that a gallon of hot working fluid is sufficient to carry enough heat to vaporize a gallon of water used in the power turbine. What is more, it pumps efficiently after cool down to under the temperature of boiling water.

An engineer can live quite happily with those types of numbers. And there is no special need to look further. Just do not grab any exposed pipes unless you feel like leaving your skin.


Dow Captures Solar Power With Fluid Technology


by Staff Writers
Midland MI (SPX) Jun 09, 2009

http://www.solardaily.com/reports/Dow_Captures_Solar_Power_With_Fluid_Technology_999.html

Dow Chemical is shedding light on Concentrating Solar Power systems (CSP) with DOWTHERM A heat transfer fluids which can collect, transport and store solar generated heat.

CSP technology uses mirrors to reflect and concentrate sunlight onto receivers that collect solar energy and convert it to heat. DOWTHERM A heat transfer fluids collect the heat energy and transport it to a power generating station. The transported heat converts water to steam, which in turn drives turbines to make electricity.

"We are committed to harnessing the vast potential of the sun to continue setting the standard for sustainability," said Neil Hawkins, Dow's vice president of sustainability.

"In addition to innovations in sustainable chemistry that result in products like DOWTHERM A, we've also made significant advancements in photovoltaic technology through the development of a game-changing residential solar shingle by the Dow Solar Solutions business. Our 2015 sustainability goals are driving innovation that is good for business and good for the world."

Dow has supplied, or is in the process of supplying, enough DOWTHERM A globally to generate more than 500 megawatts of electricity from the sun - positioning its Performance Fluids Business as the leading supplier of heat transfer fluids in the world for parabolic trough based solar systems.

Solar power producers in the United States, Middle East, Spain, Australia, India and other locations are tapping into Dow's technology and world-scale production and supply capabilities.

Recent projects in Spain will be using more than 5,000 metric tons of DOWTHERM A heat transfer fluids that will eventually generate enough electricity for about 120,000 households. These plants will also prevent the release of about 350,000 tons of carbon dioxide that would have otherwise been released into the aosphere had traditional fuels been used.

Dow has demonstrated its commient and leadership in energy efficiency all around the world. Over the last 14 years, Dow's efforts to conserve power globally have resulted in saving more than 1,600 trillion BTUs of energy and prevented the release of about 86 million metric tons of carbon dioxide.

http://www.dow.com/heattrans/prod/synthetic/dowtherm.htm

DOWTHERM™ A heat transfer fluid is a eutectic mixture of two very stable compounds, biphenyl (C12H10) and diphenyl oxide (C12H10O). The fluid is dyed clear to light yellow to aid in leak detection. DOWTHERM A fluid may be used in systems employing either liquid phase or vapor phase heating. Suitable applications include indirect heat transfer.


DOWTHERM G heat transfer fluid contains a mixture of di- and tri-aryl ethers that provide unequaled performance in liquid phase heat transfer systems. It is the most thermally stable low pressure liquid phase heat transfer fluid on the market today and has excellent flow characteristics at low temperatures.


DOWTHERM J heat transfer fluid is a mixture of isomers of an alkylated aromatic specially engineered for demanding low-temperature applications in liquid phase pressurized systems. DOWTHERM J fluid offers outstanding low-temperature pumpability and excellent thermal stability for protection against accidental overheating. Suitable applications include single fluid heating and cooling.


DOWTHERM MX heat transfer fluid is a mixture of alkylated aromatics designed for use as an alternative to hot oils in liquid phase heat transfer systems. DOWTHERM MX fluid is suitable for use in non-pressurized systems, its good low temperature properties allow for low temperature start-up and pumpability. Expansion Tank Design: Even though DOWTHERM MX fluid can be operated in a non-pressurized system, it is recommended that the tank have an inert atmosphere. Nitrogen padding should be used on the expansion tank to exclude oxygen from the heat transfer system. The presence of oxygen will cause accelerated fluid degradation, which will considerably shorten the life of the fluid.


DOWTHERM Q heat transfer fluid contains a mixture of diphenylethane and alkylated aromatics. Compared to hot oils, it exhibits better thermal stability, particularly at the upper end of hot oils' use range, and significantly better low-temperature pumpability. Suitable applications include use as an alternative to hot oils in liquid phase heat transfer applications.


DOWTHERM RP heat transfer fluid is a diaryl alkyl intended for use in applications that require liquid phase heat transfer. Unlike other low pressure fluids — including partially hydrogenated terphenyls and dibenzyl toluene fluids — DOWTHERM RP fluid degrades primarily to low molecular weight products. This reduces the need to remove high molecular weight material from the system, resulting in longer fluid life, reduced fluid makeup requirements, less system downtime, and lower fluid and maintenance expense over the life of the heat transfer system. Suitable applications include non-pressurized or low pressure liquid phase systems including polyester, nylon, and other synthetic fiber processing facilities.


DOWTHERM T heat transfer fluid is a mixture of C14-C30 alkyl benzenes intended for use in applications that require liquid phase heat transfer. Suitable applications: Non-pressurized liquid phase systems with a maximum temperature of 550°F (288°C).



DOWTHERM A (21KB PDF)
EuropeNorth AmericaLatin AmericaAsia-PacificIndia, Middle East & Africa
Oil & Gas, Plastic Processing, Chemical Processing, Solar Energy
Liquid phase: 15°C to 400°C (60°F to 750°F) Vapor phase: 257°C to 400°C (495°F to 750°F)

DOWTHERM G (19KB PDF)
EuropeNorth AmericaLatin AmericaAsia-PacificIndia, Middle East & Africa
Oil & Gas, Plastic Processing, Chemical Processing, Heat Recovery
29°C to 371°C (-20°F to 700°F)

DOWTHERM J (29KB PDF)
EuropeNorth AmericaLatin AmericaAsia-PacificIndia, Middle East & Africa
Pharmaceutical, Chemical Processing
-80°C to 315°C (-100°F to 600°F). Vapor Phase 181°C to 315°C (358°F to 600°F)

DOWTHERM MX (17KB PDF)
EuropeNorth AmericaLatin AmericaAsia-PacificIndia, Middle East & Africa
Chemical Processing
330°C (625°F)

DOWTHERM Q (25KB PDF)
EuropeNorth AmericaLatin AmericaAsia-PacificIndia, Middle East & Africa
Oil & Gas, Chemical Processing, Heat Recovery
-35°C to 330°C (-30°F to 625°F)

DOWTHERM RP (26KB PDF)
EuropeNorth AmericaLatin AmericaAsia-PacificIndia, Middle East & Africa
Oil & Gas, Heat Recovery, Plastics and Chemical Processing
maximum bulk temperature of 350°C (660°F) and amaximum film temperature of 375°C (710°F)

DOWTHERM T (24KB PDF)
EuropeNorth AmericaLatin AmericaAsia-PacificIndia, Middle East & Africa
Chemical ProcessingOil & Gas
288°C (550°F) Bulk temperature of 315°C (600°F)

Tuesday, July 24, 2007

Refrigeration devices

I have had some comment on the technology of refrigeration which is very well placed.

The system that I have described to date is no more than our stripped down conventional refrigerator, not because it is the best solution but because it works today. This technology arose in the early twentieth century amid a great deal of experimentation similar to that of the automobile. In other words, it was messy and a lot of very good ideas never made it.

Some years back I met an inventor who had picked up on chemical disassociation as a method to collect energy. The working fluid was sent through the focal point of a parabolic mirror, then passed through a heat exchanger as it recombined. Of course there were technical problems, mostly to do with the small size of the unit. What I did see was a sun driven refrigerator with a very simple (perhaps too simple) system that was close to been bullet proof. That was his first generation prototype and it worked fine.

The energy collector that he used was a parabolic mirror with a broad collector just behind the focal point. It was parabolic in the vertical and linear in the horizontal. This same system can be used to readily drive an expander to drive a power generator and possibly to also heat water.

Both devices are cheap to manufacture and are independent of any power grid. Again battery storage during the day will power the television at night.

The only reason the developed world has never developed these devices is simply because we do not need to. Everywhere else does need this technology for daily living.

The important thing to remember is that the failed ideas of the early twentieth century, failed often enough because material science was in its infancy as was chemistry. It is very timely to dust of those old patents and to see if there is a superior economic strategy that can be implemented now.