Saturated Water: Difference between revisions
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*If you increase pressure, water will boil above 212F. | *If you increase pressure, water will boil above 212F. | ||
*Calculator - give it pressure - and it tells you what temperature water boils at and its energy content at that temperature - [http://www2.spiraxsarco.com/esc/SW_Properties.aspx] | *Calculator - give it pressure - and it tells you what temperature water boils at and its energy content at that temperature - [http://www2.spiraxsarco.com/esc/SW_Properties.aspx] | ||
*18 bar water is at 209C and | *18 bar water is at 209C and 900kJ/kg, at 1 bar it is 100C and 420kJ/kg. At 18 bar, density is 860 kg/m3 | ||
*The difference beween the two is 460 kJ/kg that can be released as steam energy. This appears to be the stored energy that can be extracted by a steam engine | *The difference beween the two is 460 kJ/kg that can be released as steam energy. This appears to be the stored energy that can be extracted by a steam engine | ||
*Thus, a 10,000 gallon (38 cubic meter) tank at 18 bar contains 38*860 kg or 33,000 kg | *Thus, a 10,000 gallon (38 cubic meter) tank at 18 bar contains 38*860 kg or 33,000 kg | ||
*Energy releasable from this is 33,000* | *Energy releasable from this is 33,000*480kJ = 16 GJ. | ||
*1 GJ = 280 kWhr | *1 GJ = 280 kWhr | ||
*Thus | *Thus 4400 kWhr. This paper shows 20-30 kWhr/m3 (about 1000 kWhr for 38 cubic meters) storage capacity which considers the pressure drop or about 1/4 of the theoretical value. | ||
*Extracted at 15% efficiency via a steam engine, that is 590 kWhr. But 1/4 the value for effective extraction due to pressure loss through discharge - and have 150 kWhr. Decent, and probably sufficient. | *Extracted at 15% efficiency via a steam engine, that is 590 kWhr. But 1/4 the value for effective extraction due to pressure loss through discharge - and have 150 kWhr. Decent, and probably sufficient. | ||
*Acceptable. | *Acceptable. | ||
Revision as of 00:04, 4 February 2018
To 2 significant figures:
- Definition of Saturated Water
- Water boiling temperature depends on pressure.
- If you increase pressure, water will boil above 212F.
- Calculator - give it pressure - and it tells you what temperature water boils at and its energy content at that temperature - [1]
- 18 bar water is at 209C and 900kJ/kg, at 1 bar it is 100C and 420kJ/kg. At 18 bar, density is 860 kg/m3
- The difference beween the two is 460 kJ/kg that can be released as steam energy. This appears to be the stored energy that can be extracted by a steam engine
- Thus, a 10,000 gallon (38 cubic meter) tank at 18 bar contains 38*860 kg or 33,000 kg
- Energy releasable from this is 33,000*480kJ = 16 GJ.
- 1 GJ = 280 kWhr
- Thus 4400 kWhr. This paper shows 20-30 kWhr/m3 (about 1000 kWhr for 38 cubic meters) storage capacity which considers the pressure drop or about 1/4 of the theoretical value.
- Extracted at 15% efficiency via a steam engine, that is 590 kWhr. But 1/4 the value for effective extraction due to pressure loss through discharge - and have 150 kWhr. Decent, and probably sufficient.
- Acceptable.
- This means that a 1000 gallon propane tank gets you about 15 kWhr of storage when extracted with a steam engine. At $2500 tank cost - this is $170/kwHr. 2x cheaper than Lithium Ion batteries, and about same as lead acid batteries. But longer life for propane tank.
- For anyone that understands this, this is revolution and end of battery storage on a path to ecological means of storage via solar-heated saturated water.
Technical
- "The volume specific thermal energy density depends strongly on the variation of the saturation temperature resulting from the pressure drop during discharge, characteristic values are in the range of 20–30 kW h/m3" - [2]