Heat exchange with compressed gas in energy-storage systems
In various embodiments, compressed-gas energy storage and recovery systems include a cylinder assembly for compression and/or expansion of gas, a reservoir for storage and/or supply of compressed gas, and a system for thermally conditioning gas within the reservoir.
1. A compressed-gas energy storage and recovery system comprising:
a first cylinder assembly for at least one of, over a first pressure range, compressing gas to store energy or expanding gas to recover energy, the first cylinder assembly comprising two separated chambers;
selectively fluidly connected to a chamber of the first cylinder assembly, a vent for admitting ambient air into the chamber of the first cylinder assembly for compression and for exhausting gas from the chamber of the first cylinder assembly after expansion;
selectively fluidly connected to the first cylinder assembly, a second cylinder assembly for at least one of, over a second pressure range higher than the first pressure range, compressing gas to store energy or expanding gas to recover energy, the second cylinder assembly comprising two separated chambers;
a first spray mechanism for mingling heat-exchange fluid and gas for at least one of compression or expansion within the second cylinder assembly;
selectively fluidly connected to a chamber of the second cylinder assembly, a compressed-gas reservoir for storage of gas after compression and supply of compressed gas for expansion, the compressed-gas reservoir comprising an underground cavern; and
a heat-exchange subsystem for thermally conditioning gas within the compressed-gas reservoir, the heat-exchange subsystem comprising (i) a second spray mechanism disposed within the underground cavern, (ii) a circulation apparatus for extracting liquid from a bottom portion of the underground cavern, and (iii) a conduit selectively fluidly connecting the circulation apparatus and the bottom portion of the underground cavern.
2. The system of claim 1 , wherein the heat-exchange subsystem comprises:
a heat exchanger; and
a second conduit fluidly connecting the circulation apparatus and the heat exchanger.
3. The system of claim 1 , wherein the second spray mechanism comprises at least one of a spray head or a spray rod.
4. The system of claim 1 , wherein the heat-exchange fluid comprises water and one or more additives for (i) reducing surface tension of the water and (ii) retarding or preventing corrosion.
5. The system of claim 1 , wherein the circulation apparatus comprises a water pump.
6. The system of claim 2 , wherein the heat exchanger is in fluid communication with an external heating or cooling source.
7. The system of claim 6 , wherein the external heating or cooling source comprises at least one of a fossil fuel power plant, a heat engine power plant, a solar thermal source, a geothermal source, an industrial process with waste heat, a heat pump, a heat source, a heat sink, or a source of environmentally chilled water.
8. The system of claim 6 , wherein the external heating or cooling source comprises a thermal well.
9. The system of claim 1 , further comprising a movable boundary mechanism separating the two chambers of the first cylinder assembly.
10. The system of claim 9 , further comprising, mechanically coupled to the boundary mechanism, a crankshaft for converting reciprocal motion of the boundary mechanism into rotary motion.
11. The system of claim 10 , further comprising a motor/generator coupled to the crankshaft.
12. The system of claim 1 , wherein the heat-exchange subsystem and the first spray mechanism both utilize the same heat-exchange fluid for heat exchange.
13. The system of claim 1 , wherein the first spray mechanism comprises at least one of a spray head or a spray rod.
14. The system of claim 1 , further comprising a control system for enforcing at least one of substantially isothermal expansion or substantially isothermal compression within at least one of the first cylinder assembly or the second cylinder assembly.
15. The system of claim 1 , wherein the heat-exchange subsystem comprises a heat-transfer fluid incorporating an additive to reduce the surface tension of the heat-transfer fluid.