Increased power in compressed-gas energy storage and recovery

Abstract

In various embodiments, energy is stored or recovered via super-atmospheric compression and/or expansion of gas in conjunction with substantially adiabatic compression and/or expansion from or to atmospheric pressure.

1 .- 40 . (canceled) 
     
     
         41 . A method for energy storage, the method comprising:
 during a first compression stage, compressing gas from approximately atmospheric pressure to a first super-atmospheric pressure via rotational motion within a first compression mechanism;   during a second compression stage, compressing gas from the first super-atmospheric pressure to a second super-atmospheric pressure larger than the first super-atmospheric pressure via linear piston motion within a second compression mechanism; and   during at least one of the first or second compression stages, exchanging heat between the gas and a heat-transfer liquid to thermally condition the gas, thereby increasing efficiency of the energy storage.   
     
     
         42 . The method of  claim 41 , further comprising spraying heat-transfer liquid into the gas. 
     
     
         43 . The method of  claim 41 , wherein the thermal conditioning renders at least one of the first or second compression stages substantially isothermal. 
     
     
         44 . The method of  claim 41 , further comprising circulating the heat-transfer fluid to a heat exchanger to regulate a temperature of the heat-transfer fluid. 
     
     
         45 . The method of  claim 41 , wherein the first compression mechanism comprises a blower of a type selected from the group consisting of lobe-type, centrifugal, and axial-turbine-type. 
     
     
         46 . The method of  claim 41 , wherein the second compression mechanism comprises a cylinder assembly. 
     
     
         47 . The method of  claim 41 , wherein the first compression stage is substantially adiabatic. 
     
     
         48 . The method of  claim 41 , further comprising driving at least one of the first or second compression mechanisms with a motor/generator. 
     
     
         49 . The method of  claim 41 , further comprising, after the second compression stage, storing compressed gas within a storage reservoir. 
     
     
         50 . The method of  claim 49 , wherein the storage reservoir comprises one or more pressure vessels. 
     
     
         51 . The method of  claim 49 , wherein the storage reservoir comprises a cavern. 
     
     
         52 . The method of  claim 41 , further comprising converting linear motion of the second compression stage to rotational motion via a crankshaft. 
     
     
         53 . The method of  claim 41 , further comprising, prior to the first compression stage, admitting gas via a vent to atmosphere. 
     
     
         54 . The method of  claim 41 , wherein the first super-atmospheric pressure is approximately 15 psig or less. 
     
     
         55 . The method of  claim 41 , further comprising supplying gas at approximately the first super-atmospheric pressure to a conduit between the first and second compression mechanisms. 
     
     
         56 . The method of  claim 41 , further comprising detecting pressure within at least one of the first or second compression mechanisms. 
     
     
         57 . The method of  claim 41 , further comprising detecting temperature within at least one of the first or second compression mechanisms. 
     
     
         58 . The method of  claim 41 , further comprising detecting gas flow rate within at least one of the first or second compression mechanisms. 
     
     
         59 . The method of  claim 41 , further comprising:
 during a first expansion stage, expanding gas from the second super-atmospheric pressure to the first super-atmospheric pressure via linear piston motion within the second compression mechanism;   during a second expansion stage, expanding gas from the first super-atmospheric pressure to approximately atmospheric pressure via rotational motion within the first compression mechanism; and   during at least one of the first or second expansion stages, exchanging heat between the gas and heat-transfer liquid to thermally condition the gas.   
     
     
         60 . The method of  claim 59 , further comprising, after the second expansion stage, venting gas to atmosphere.