Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange

Abstract

In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.

What is claimed is: 
     
         1 .- 33 . (canceled) 
     
     
         34 . A compressed-gas energy storage and recovery system comprising:
 a cylinder assembly comprising a pneumatic chamber for compressing gas to store energy and expanding gas to recover energy and a hydraulic chamber, separated from the pneumatic chamber;   selectively fluidly connected to the pneumatic chamber, (i) a compressed-gas reservoir for storage of gas after compression and supply of compressed gas for expansion thereof, and (ii) a vent for exhausting expanded gas to atmosphere and supply of gas for compression thereof;   a spray mechanism for introducing heat-transfer fluid within the pneumatic chamber of the cylinder assembly to exchange heat with gas therein, thereby increasing efficiency of the energy storage and recovery, the spray mechanism comprising a plurality of nozzles for collectively producing an aggregate spray filling substantially an entire volume of the pneumatic chamber; and   a circulation apparatus for circulating the heat-transfer fluid to the spray mechanism,   wherein the aggregate spray comprises a plurality of overlapping individual sprays each produced by one of the plurality of nozzles.   
     
     
         35 . The system of  claim 34 , wherein each individual spray is an atomized spray of individual droplets. 
     
     
         36 . The system of  claim 35 , wherein the individual droplets have an average diameter ranging from approximately 0.2 mm to approximately 1 mm. 
     
     
         37 . The system of  claim 34 , wherein the plurality of nozzles maintains a Weber value of gas within the chamber of at least 40. 
     
     
         38 . The system of  claim 34 , wherein each nozzle maintains a pressure drop thereacross of less than approximately 50 psi. 
     
     
         39 . The system of  claim 34 , wherein at least one nozzle has a divergent cross-sectional profile. 
     
     
         40 . The system of  claim 34 , wherein at least one nozzle comprises a mechanism for breaking up a flow of heat-transfer fluid therethrough. 
     
     
         41 . The system of  claim 40 , wherein the mechanism comprises at least one of a plurality of vanes or a corkscrew. 
     
     
         42 . The system of  claim 34 , further comprising a control system for controlling the introduction of heat-transfer fluid into the pneumatic chamber such that the at least one of compression or expansion of gas is substantially isothermal. 
     
     
         43 . The system of  claim 34 , wherein the plurality of nozzles is organized into at least two nozzle groups, at least one nozzle group not being active during a portion of a single cycle of compression or expansion. 
     
     
         44 . A compressed-gas energy storage and recovery system comprising:
 a cylinder assembly comprising (i) a first chamber for compressing gas to store energy and expanding gas to recover energy, (ii) a second chamber, (iii) a movable piston separating the first chamber from the second chamber, and (iv) a piston rod connected to the movable piston;   selectively fluidly connected to the first chamber, (i) a compressed-gas reservoir for storage of gas after compression and supply of compressed gas for expansion thereof, and (ii) a vent for exhausting expanded gas to atmosphere and supply of gas for compression thereof;   a spray mechanism for introducing heat-transfer fluid within the first chamber of the cylinder assembly to exchange heat with gas therein, thereby increasing efficiency of the energy storage and recovery, the spray mechanism comprising a plurality of nozzles for collectively producing an aggregate spray filling substantially an entire volume of the first chamber; and   a circulation apparatus for circulating the heat-transfer fluid to the spray mechanism,   wherein (i) the aggregate spray comprises a plurality of overlapping individual sprays each produced by one of the plurality of nozzles, and (ii) the movable piston and piston rod define a fluid passageway selectively fluidly connected to the circulation apparatus.   
     
     
         45 . The system of  claim 44 , wherein each individual spray is an atomized spray of individual droplets. 
     
     
         46 . The system of  claim 45 , wherein the individual droplets have an average diameter ranging from approximately 0.2 mm to approximately 1 mm. 
     
     
         47 . The system of  claim 44 , wherein the plurality of nozzles maintains a Weber value of gas within the chamber of at least 40. 
     
     
         48 . The system of  claim 44 , wherein each nozzle maintains a pressure drop thereacross of less than approximately 50 psi. 
     
     
         49 . The system of  claim 44 , wherein at least one nozzle has a divergent cross-sectional profile. 
     
     
         50 . The system of  claim 44 , wherein at least one nozzle comprises a mechanism for breaking up a flow of heat-transfer fluid therethrough. 
     
     
         51 . The system of  claim 50 , wherein the mechanism comprises at least one of a plurality of vanes or a corkscrew. 
     
     
         52 . The system of  claim 44 , further comprising a control system for controlling the introduction of heat-transfer fluid into the first chamber such that the at least one of compression or expansion of gas is substantially isothermal. 
     
     
         53 . The system of  claim 44 , wherein the plurality of nozzles is organized into at least two nozzle groups, at least one nozzle group not being active during a portion of a single cycle of compression or expansion.