MoltenSalt

=== Heat capacity ===
Heat capacity of salt is much higher than mineral oil?
=== Molten salt ===
* http://www.treehugger.com/files/2008/01/molten_salt_as.php
* http://www.countercurrents.org/mason311207.htm
http://www.hamiltonsundstrandcorp.com/vgn-ext-templating/v/index.jsp?vgnextoid=873f0b791c152110VgnVCM1000007301000aRCRD
* http://www.usregroup.com/
* http://www.alt-energy.info/archives/1433 steam turbine, salt
* http://link.aip.org/link/?JSEEDO/124/170/1 molten salt pumps
==Notes==
* The effective thermal energy from the sun is 1Kwh/square meter. This means that a constant 1Kwatt thermal energy is absorbed over 1 square meter during an hour of sun shine.
* 4x4m Fresnel reflector generates 16Kwh thermal energy.
* Fahrenheit to Celsius => Fx2.
How much volume of salt is needed to store this 16Kwh at a temperature of 700degree C ?
* storage capacity of salt is 43btu per 1cube feet/ farenheit. or 96btu per cubic feet/degree C.
* 0.293Btu = 1watt.hour
* 28.13Watthours /cubic feet/degree C. This means that by raising the temperature of one cubic feet of salt by one degree Celsius 28.13Watthours thermal energy is stored.
* Thus to raise 1cubic feet of salt to 600C will need (28.13 x 600 = 16Kwh)
* Thus one hour of thermal energy from a 4x4m Fresnel reflector is stored at 600C in one cubic feet of salt.
* Molten salts thus has a very good thermal storage efficiency to weight ratio.
* The salt looses only 1degree Celsius per day apparently. But I don't know if this is in a vacuum or open air.
Coastal chem
http://www.coastalchem.com/PDFs/HITECSALT/Hitec%20Solar%20Salt.pdf
http://en.wikipedia.org/wiki/Watt_hour
http://en.wikipedia.org/wiki/British_thermal_unit
From the MoltenSalts pdf file under links the thermal storage capacity of salt is listed as 43btu per 1cube feet/ farenheit.
96btu x 400C = 34400 btu to take on cube of salt to 400degrees. This is 10kwh. A 4x4m FMA(fresnel mir) generates 16Kwh, it will take 37min to heat one square foot of salt. One cubic foot of salt at 400C stores 10kwh thermal energy. At 20% conversion efficiency a steam engine will generate 2kwh electricity. Thus it would be practicle to melt the salt and transport it to residens powering small 2kwh or 1kwh steam engines as per the Mike Brown solution.
There is 27cube feet in one meter. Thus 43x27 = 1161btu / m3/farenheit
Which is 2322 BTU/m3/degree celsius. (Multiply fharenheit by 2 to get celcius.)
0.293BTU = 1watt.hour
2322 x (0.293) = 680 watt hour/1 cube meter/ celsius.
One cubic meter salt weighs one ton.
For a 100C increase in temperature of salt , multiply 680watt with 100.
At 200C 680wattx200 = 136Kwatt hours.
At 400C 680wattx400 = 272Kwatt hours.(thermal)
Conversion efficiency of 15% with steam engine means 41Kwh electicity
is generated in one hour. With 20% efficiency 54Kwh electricity.
The salt looses only 1 degree C in a 24hour period(vacuum sealed?)
If the calculations are correct, then it would seem that a huge amount
of energy can be thermally stored in salts.
Running water through a heat exchanger emmersed in the salt will
transfer the heat generating super heated steam, cooling down the salt back to 200C. At 200C it is still molten and must be reheated with the sun. Use the Spanish solar farm idea with a single tower surrounded by mirrors or Fresnel mirror array(FMA) assembly.
To focus 400C over a 1foot container will need about 167 mirrors 1x1foot square, 4x4m. Attach a larger empty gas bottle behind the boiler plate on the FMA focus point, with a small high temperature pump. Pump the 200C salt through the boiler focus point to heat back to 400C and then remove the larger empty gas bottle, replacing it with a new batch.
The manual labor invovled in this would make the solar pole idea a better solution.
=== Slashdot ===
* http://slashdot.org/article.pl?sid=08/01/02/2032213
* http://www.courant.com/news/custom/topnews/hcu-hamiltonenergy0102,0,7225438.story
http://www.renewableenergyworld.com/rea/news/article/2008/06/storing-the-sun-molten-salt-provides-highly-efficient-thermal-storage-52873
http://www.scientificamerican.com/article.cfm?id=how-to-use-solar-energy-at-night
http://mrgreenbiz.wordpress.com/2009/03/31/molten-salt-as-solar-heat-battery/
http://www.p2pays.org/ref/22/21030.pdf pump
http://blogs.physicstoday.org/newspicks/2009/03/solar-plant-to-utilize-molten.html
http://community.seattletimes.nwsource.com/reader_feedback/public/services/display_post_redirect.php?id=506048
http://www.cogeneration.net/molten_salt_storage.htm
http://mmadan.wordpress.com/2009/04/29/molten-salt-takes-solar-thermal-into-24x7-mode/
http://discovermagazine.com/2009/jun/18-forget-lightning-how-do-we-catch-sunshine-in-a-bottle
http://www.greencon.co.za/blog/2009/05/storing-energy-the-green-way-for-those-rainy-days/
=== patents ===
http://www.freshpatents.com/Thermal-energy-storage-systems-and-methods-dt20081127ptan20080289793.php
=== molten salt car ===
http://www.greencarcongress.com/2008/12/fedex-express-o.html
=== links ===
Thermal storage
Category:Sasecurity
Category:Energy