Valve activation in compressed-gas energy storage and recovery systems

Abstract

In various embodiments, valve efficiency and reliability are enhanced via use of hydraulic or magnetic valve actuation, valves configured for increased actuation speed, and/or valves controlled to reduce collision forces during actuation.

What is claimed is: 
     
         1 . A method for at least one of storing energy in or recovering energy with an energy-storage system comprising (i) a cylinder assembly having a valve for controlling fluid flow into and out of the cylinder assembly through a gated port, the valve comprising a valve member for occluding the gated port, and (ii) an actuation system for actuating the valve, the actuation system comprising (a) an actuation cylinder and (b) a piston disposed within and dividing the actuation cylinder into first and second chambers, the method comprising:
 within the cylinder assembly, at least one of (i) compressing gas to store energy or (ii) expanding gas to recover energy; and   at least one of prior to, during, or after the at least one of compression or expansion, at least one of admitting fluid into or exhausting fluid from the cylinder assembly at least in part by actuating the valve from a closed state to an open state by admitting fluid into the first chamber of the actuation cylinder to increase fluid pressure therein, thereby moving the piston toward the second chamber,   wherein, during the actuation, (i) fluid exits the second chamber of the actuation cylinder at a first rate to maximize speed of the piston motion, and (ii) thereafter, fluid exits the second chamber at a second rate slower than the first rate to decelerate the piston before the piston reaches an end surface of the actuation cylinder.   
     
     
         2 . The method of  claim 1 , wherein the second rate of fluid flow decreases as the piston moves toward the end surface of the actuation cylinder. 
     
     
         3 . The method of  claim 1 , wherein, during the actuation, the piston occludes at least a portion of an orifice in the second chamber as the piston moves toward an end surface of the actuation cylinder, thereby slowing the flow of fluid from the second chamber from the first rate to the second rate. 
     
     
         4 . The method of  claim 3 , wherein, when the piston is disposed proximate the end surface, the orifice is completely occluded by the piston. 
     
     
         5 . The method of  claim 3 , wherein a lateral dimension of at least a portion of the orifice varies as a function of distance from the end surface of the actuation cylinder. 
     
     
         6 . The method of  claim 3 , wherein (i) a lateral dimension of a first portion of the orifice does not vary as a function of distance from the end surface of the actuation cylinder and (ii) a lateral dimension of a second portion of the orifice varies as a function of distance from the end surface of the actuation cylinder. 
     
     
         7 . The method of  claim 3 , wherein a lateral boundary of at least a portion of the orifice has a shape defined by a function y(x)=C(V max   2 −2Ax) 1/2 , where C is a constant, V max  is a velocity of the piston in the actuation cylinder when the orifice is not occluded, and A is a magnitude of deceleration of the piston in the actuation cylinder when the orifice is partially occluded. 
     
     
         8 . The method of  claim 1 , wherein fluid is admitted into the first chamber through both (i) an occludable orifice configured to be at least partially occluded by the piston during movement of the piston within the actuation cylinder, and (ii) a fixed orifice configured to not be occluded by the piston during movement of the piston within the actuation cylinder. 
     
     
         9 . The method of  claim 1 , wherein, during at least a portion of the actuation, fluid exits the second chamber through both (i) an occludable orifice configured to be at least partially occluded by the piston during movement of the piston within the actuation cylinder, and (ii) a fixed orifice configured to not be occluded by the piston during movement of the piston within the actuation cylinder. 
     
     
         10 . A method for at least one of storing energy in or recovering energy with an energy-storage system comprising (i) a cylinder assembly having a valve for controlling fluid flow into and out of the cylinder assembly through a gated port, the valve comprising a valve member for occluding the gated port, and (ii) an actuation system for actuating the valve, the actuation system comprising (a) an actuation cylinder, (b) a piston disposed within and dividing the actuation cylinder into first and second chambers, and (c) an occludable orifice configured to be at least partially occluded by the piston during movement of the piston within the actuation cylinder, the method comprising:
 within the cylinder assembly, at least one of (i) compressing gas to store energy or (ii) expanding gas to recover energy; and   at least one of prior to, during, or after the at least one of compression or expansion, at least one of admitting fluid into or exhausting fluid from the cylinder assembly at least in part by actuating the valve from a closed state to an open state by admitting fluid into the first chamber of the actuation cylinder to increase fluid pressure therein, thereby moving the piston toward the second chamber,   wherein, during the actuation, (i) fluid flows out of the second chamber through the occludable orifice unoccluded by the piston, thereby maximizing speed of the piston motion, and (ii) thereafter, the piston occludes at least a portion of the occludable orifice, whereby fluid flow from the second chamber is decreased to decelerate the piston before the piston reaches an end surface of the actuation cylinder.   
     
     
         11 . The method of  claim 10 , wherein the occludable orifice is completely occluded by the piston by the end of the actuation. 
     
     
         12 . The method of  claim 10 , wherein a lateral dimension of at least a portion of the occludable orifice varies as a function of distance from an end surface of the actuation cylinder. 
     
     
         13 . The method of  claim 10 , wherein (i) a lateral dimension of a first portion of the occludable orifice does not vary as a function of distance from an end surface of the actuation cylinder and (ii) a lateral dimension of a second portion of the occludable orifice varies as a function of distance from the end surface of the actuation cylinder. 
     
     
         14 . The method of  claim 10 , wherein a lateral boundary of at least a portion of the occludable orifice has a shape defined by a function y(x)=C(V max   2 −2Ax) 1/2 , where C is a constant, V max  is a velocity of the piston in the actuation cylinder when the occludable orifice is not occluded, and A is a magnitude of deceleration of the piston in the actuation cylinder when the occludable orifice is partially occluded. 
     
     
         15 . The method of  claim 10 , wherein fluid is admitted into the first chamber through both (i) a second occludable orifice configured to be at least partially occluded by the piston during movement of the piston within the actuation cylinder, and (ii) a fixed orifice configured to not be occluded by the piston during movement of the piston within the actuation cylinder. 
     
     
         16 . The method of  claim 10 , wherein, during at least a portion of the actuation, fluid exits the second chamber through both (i) the occludable orifice, and (ii) a fixed orifice configured to not be occluded by the piston during movement of the piston within the actuation cylinder.