High-efficiency heat exchange in compressed-gas energy storage systems
View Patent ↗In various embodiments, efficiency of energy storage and recovery systems employing compressed air and liquid heat exchange is improved via control of the system operation and/or the properties of the heat-exchange liquid.
1. A method for improving efficiency of a compressed-gas energy storage and recovery system, the method comprising:
providing a heat-transfer fluid conditioned to at least one of (i) reduce a solubility of a gas in the heat-transfer fluid or (ii) reduce a rate of dissolution of a gas into the heat-transfer fluid;
at least one of (i) compressing the gas to store energy or (ii) expanding the gas to recover energy; and
thereduring, exchanging heat between the gas and the conditioned heat-transfer fluid, thereby increasing efficiency of the energy storage and recovery.
2. The method of claim 1 , wherein the conditioned heat-transfer fluid comprises a solute therein.
3. The method of claim 2 , wherein the solute comprises a salt.
4. The method of claim 3 , wherein the salt comprises at least one of sodium chloride or calcium chloride.
5. The method of claim 2 , wherein the solute comprises a surfactant.
6. The method of claim 5 , wherein the surfactant comprises at least one of sodium dodecyl sulphate, iso-amyl alcohol, or sodium tetradecyl sulphate.
7. The method of claim 2 , wherein the solute reduces a surface tension of the heat-transfer fluid.
8. The method of claim 7 , wherein exchanging heat between the gas and the conditioned heat-transfer fluid comprises spraying the conditioned heat-transfer fluid into the gas, an injection velocity of the spraying being less than an injection velocity required to form a spray from the heat-transfer fluid without the solute.
9. The method of claim 2 , further comprising heating the conditioned heat-transfer fluid to increase a solubility of the solute in the conditioned heat-transfer fluid.
10. The method of claim 1 , further comprising at least one of (i) venting expanded gas to atmosphere or (ii) storing compressed gas in a compressed-gas reservoir.
11. The method of claim 1 , wherein (i) energy stored during compression of the gas originates from an intermittent renewable energy source of wind or solar energy, and (ii) energy is recovered via expansion of the gas when the intermittent renewable energy source is nonfunctional.
12. The method of claim 1 , wherein exchanging heat between the gas and the conditioned heat-transfer fluid comprises spraying the conditioned heat-transfer fluid into the gas.
13. The method of claim 1 , wherein the heat exchange between the gas and the conditioned heat-transfer fluid renders the at least one of compression or expansion substantially isothermal.
14. The method of claim 1 , wherein the gas is at least one of compressed or expanded within a cylinder assembly.
15. The method of claim 14 , further comprising, prior to the at least one of compression or expansion, introducing the gas into the cylinder assembly substantially isobarically, wherein heat is not exchanged between the gas and the conditioned heat-transfer fluid thereduring.
16. The method of claim 14 , further comprising, after the at least one of compression or expansion, exhausting the gas from the cylinder assembly substantially isobarically, wherein heat is not exchanged between the gas and the conditioned heat-transfer fluid thereduring.
17. The method of claim 1 , wherein the heat-transfer fluid comprises water.
18. The method of claim 1 , wherein providing the heat-transfer fluid conditioned to at least one of (i) reduce a solubility of a gas in the heat-transfer fluid or (ii) reduce a rate of dissolution of a gas into the heat-transfer fluid comprises heating the heat-transfer fluid to an elevated temperature.
19. The method of claim 18 , wherein the gas is at least one of expanded or compressed at approximately the elevated temperature.
20. The method of claim 18 , wherein the elevated temperature is selected from the range of approximately 40° C. to approximately 70° C.
21. The method of claim 18 , wherein the elevated temperature is selected from the range of approximately 70° C. to approximately 100° C.
22. The method of claim 18 , further comprising spraying the conditioned heat-transfer fluid into the gas.
23. The method of claim 1 , further comprising spraying the conditioned heat-transfer fluid into the gas.
24. The method of claim 1 , wherein the heat-transfer fluid contains an additive therein, the additive at least one of (i) retarding or preventing corrosion, (ii) preventing formation of or killing microorganisms, or (iii) comprising a defoaming agent.
25. The method of claim 10 , wherein compressed gas is stored in the compressed-gas reservoir, the compressed-gas reservoir comprising a pressure vessel.
26. The method of claim 10 , wherein compressed gas is stored in the compressed-gas reservoir, the compressed-gas reservoir comprising a cavern.
27. The method of claim 1 , wherein the conditioned heat-transfer fluid forms a foam with the gas.
28. The method of claim 27 , further comprising defoaming the gas after the at least one of compressing or expanding the gas.
29. The method of claim 28 , wherein defoaming the gas comprises introducing a defoaming additive into the heat-transfer fluid.