Compressed air energy storage system utilizing two-phase flow to facilitate heat exchange

Abstract

A compressed-air energy storage system according to embodiments of the present invention comprises a reversible mechanism to compress and expand air, one or more compressed air storage tanks, a control system, one or more heat exchangers, and, in certain embodiments of the invention, a motor-generator. The reversible air compressor-expander uses mechanical power to compress air (when it is acting as a compressor) and converts the energy stored in compressed air to mechanical power (when it is acting as an expander). In certain embodiments, the compressor-expander comprises one or more stages, each stage consisting of pressure vessel (the “pressure cell”) partially filled with water or other liquid. In some embodiments, the pressure vessel communicates with one or more cylinder devices to exchange air and liquid with the cylinder chamber(s) thereof. Suitable valving allows air to enter and leave the pressure cell and cylinder device, if present, under electronic control.

What is claimed is: 
     
         1 . A system comprising:
 a host computer comprising a processor in electronic communication with a non-transitory computer-readable storage medium, the non-transitory computer readable storage medium having stored thereon one or more codes to instruct the processor to,   receive a signal indicating a property of a compressed gas storage unit, and   in response to the received signal, dynamically control a valve to achieve a maximum expected temperature difference of a gas released from the compressed gas storage unit.   
     
     
         2 . A system as in  claim 1  further comprising a temperature sensor, wherein the property comprises a temperature. 
     
     
         3 . A system as in  claim 2  wherein the temperature sensor is located in the compressed gas storage unit. 
     
     
         4 . A system as in  claim 1  further comprising a pressure sensor, wherein the property comprises a pressure. 
     
     
         5 . A system as in  claim 4  wherein the pressure sensor is located in the compressed gas storage unit. 
     
     
         6 . A system as in  claim 1  further comprising a humidity sensor, wherein the property comprises a humidity. 
     
     
         7 . A system as in  claim 1  further comprising a flow rate sensor, wherein the property comprises a flow rate. 
     
     
         8 . A system as in  claim 1  wherein the compressed gas storage unit comprises a composite material. 
     
     
         9 . A system as in  claim 8  wherein the composite material comprises a fiber. 
     
     
         10 . A system as in  claim 9  wherein the fiber comprises carbon fiber. 
     
     
         11 . A system as in  claim 1  wherein the non-transitory computer readable storage medium has further stored thereon one or more codes to instruct the processor to,
 in response to the received signal, dynamically control the valve to achieve a maximized efficiency of conversion of stored energy in the gas into useful work. 
 
     
     
         12 . A system as in  claim 1  wherein the compressed gas storage unit is in thermal communication with an energy source. 
     
     
         13 . A system as in  claim 1  wherein the compressed gas storage unit is in thermal communication with the sun. 
     
     
         14 . A system as in  claim 13  wherein the compressed gas storage unit is coated with a thermal-absorbing material. 
     
     
         15 . A system as in  claim 13  wherein the compressed gas storage unit is positioned behind a barrier trapping solar energy. 
     
     
         16 . A system as in  claim 1  further comprising a pump and a liquid reservoir, wherein the non-transitory computer readable storage medium has further stored thereon one or more codes to instruct the processor to,
 cause the pump to selectively flow a liquid from the liquid reservoir into the compressed gas storage unit to replace a volume of the released gas. 
 
     
     
         17 . A system as in  claim 1  wherein the non-transitory computer readable storage medium has further stored thereon one or more codes to instruct the processor to,
 cause the pump to be driven as a hydraulic motor by liquid removed from the compressed gas storage unit by the addition of compressed gas. 
 
     
     
         18 . A system as in  claim 1  wherein the compressed gas storage unit comprises a moveable barrier defining two compartments. 
     
     
         19 . A system as in  claim 1  wherein the gas comprises compressed natural gas. 
     
     
         20 . A system as in  claim 1  wherein the non-transitory computer readable storage medium has stored thereon one or more codes to instruct the processor to communicate a signal instructing automatically causing ramp-up of a generation asset of a power supply network.