# US 8,769,943 B2 · Compressed air energy storage system utilizing two-phase flow to facilitate heat exchange > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,769,943 B2 - Document ID: US8769943B2 - Status: Granted - Kind: B2 - Application number: 13/971,057 - Filed: 2013-08-20 - Published: 2013-12-19 - Granted: 2014-07-08 - Earliest claimed: 2009-06-29 - Assignees: LightSail Energy, Inc. - Applicants: LightSail Energy, Inc. - Inventors: Danielle A. Fong; Stephen E. Crane; Edwin P. Berlin, Jr.; AmirHossein Pourmousa Abkenar; Kartikeya Mahalatkar; Yongxi Hou; Todd Bowers; Karl E. Stahlkopf - Web page: https://patentgrep.com/patent/US8769943B2 ## CPC - F01B 17/022: {with fluid heating} - F01C 13/00: Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby - F01K 25/06: using mixtures of different fluids (plants using mixtures of steam and gas F01K21/04) - F01K 25/10: the vapours being cold, e.g. ammonia, carbon dioxide, ether - F01K 27/00: Plants for converting heat or fluid energy into mechanical energy, not otherwise provided for - F02G 1/05: by varying the rate of flow or quantity of the working gas - F03D 9/17: storing energy in pressurised fluids - F03D 9/28: the apparatus being a pump or a compressor - F04B 39/06: Cooling; Heating; Prevention of freezing - F15B 1/00: Installations or systems with accumulators; Supply reservoir or sump assemblies - F15B 1/265: {with pressurised main reservoir} - F15B 13/00: Details of servomotor systems ({F15B1/04, F15B1/26, F15B3/00, F15B7/08, F15B11/02, F15B11/10,} F15B15/00 take precedence){; Valves for servomotor systems} - F15B 15/02: Mechanical layout characterised by the means for converting the movement of the fluid-actuated element into movement of the finally-operated member - F15B 15/20: Other details {, e.g. assembly with regulating devices} - F16H 3/72: with a secondary drive, e.g. regulating motor, in order to vary speed continuously - F15B 2015/208: {Special fluid pressurisation means, e.g. thermal or electrolytic} - H02J 15/20: using storage of pneumatic energy, e.g. compressed air energy storage [CAES] - Y02B 10/30: Wind power - Y02B 10/70: Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02E 50/10: Biofuels, e.g. bio-diesel - Y02E 60/16: Mechanical energy storage, e.g. flywheels or pressurised fluids - Y02E 70/30: Systems combining energy storage with energy generation of non-fossil origin - Y02T 50/678: Aviation using fuels of non-fossil origin - Y10T 137/0318: Processes - Y10T 137/0379: By fluid pressure - Y10T 137/6579: Circulating fluid in heat exchange relationship - F01B: MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES (of rotary-piston or oscillating-piston type F01C; of non-positive-displacement type F01D; internal-combustion engines F02B; combustion-product engine plants F02G; machines or engines, other than of positive-displacement type, for liquids F03B; positive-displacement engines driven by liquids F03C; wind motors F03D; positive-displacement machines for liquids F04B; rotary-piston, or oscillating-piston, positive-displacement machines for liquids F04C) - F01C: ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES (internal-combustion aspects F02B53/00, F02B55/00) - F01K: STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES (gas-turbine or jet-propulsion plants F02; nuclear power plants, engine arrangements therein G21D) - F02G: HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS (steam engine plants, special vapour plants, plants operating on either hot gas or combustion-product gases together with other fluid F01K; gas-turbine plants F02C; jet-propulsion plants F02K); USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR - F03D: WIND MOTORS - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR - F16H: GEARING - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## 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. ## Claims ### Claim 1 An apparatus comprising: a first cylinder configured to receive a first piston; a first liquid including a foaming agent; a first element configured to effect heat exchange between the first liquid and gas expanding against the piston; a first mechanical linkage configured to transmit from the first cylinder, a power of the gas expanding against the first piston in an expansion mode; and a first separator configured to receive an expanded gas-liquid mixture in the expansion mode, wherein in a compression mode the first mechanical linkage is in selective communication with a first source of shaft torque to cause the first piston to compress gas in the first cylinder while the first element effects heat exchange between the first liquid and gas being compressed within the first cylinder, wherein the first liquid is in communication with a heat source via a heat exchanger. ### Claim 2 (depends on 1) An apparatus as in claim 1 wherein the first mechanical linkage comprises a first piston rod and a crankshaft. ### Claim 3 (depends on 2) An apparatus as in claim 2 wherein the first mechanical linkage further comprises a first cross-head. ### Claim 4 (depends on 1) An apparatus as in claim 1 wherein the first element comprises a sprayer. ### Claim 5 (depends on 4) An apparatus as in claim 4 wherein the sprayer is in fluid communication with the first cylinder. ### Claim 6 (depends on 4) An apparatus as in claim 4 wherein the sprayer is in fluid communication with a mixing chamber. ### Claim 7 (depends on 4) An apparatus as in claim 4 wherein the sprayer is configured to create a mist of droplets. ### Claim 8 (depends on 1) An apparatus as in claim 1 wherein the first element comprises a bubbler. ### Claim 9 (depends on 8) An apparatus as in claim 8 wherein the bubbler is configured to introduce gas bubbles within the first liquid. ### Claim 10 (depends on 1) An apparatus as in claim 1 wherein the first element comprises a mixing chamber. ### Claim 11 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a cyclone separator. ### Claim 12 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a gravity separator. ### Claim 13 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a centrifugal separator. ### Claim 14 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a mesh type coalescer. ### Claim 15 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a vane. ### Claim 16 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a demister separator. ### Claim 17 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a baffle. ### Claim 18 (depends on 1) An apparatus as in claim 1 wherein the first separator is configured to bubble the expanded gas-liquid mixture. ### Claim 19 (depends on 1) An apparatus as in claim 1 wherein the first separator comprises a liquid trap reservoir. ### Claim 20 (depends on 1) An apparatus as in claim 1 further comprising a second separator configured to receive a compressed gas-liquid mixture in the compression mode. ### Claim 21 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a cyclone separator. ### Claim 22 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a gravity separator. ### Claim 23 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a centrifugal separator. ### Claim 24 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a mesh type coalescer. ### Claim 25 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a vane. ### Claim 26 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a demister separator. ### Claim 27 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a baffle. ### Claim 28 (depends on 20) An apparatus as in claim 20 wherein the second separator is configured to bubble the compressed gas-liquid mixture. ### Claim 29 (depends on 20) An apparatus as in claim 20 wherein the second separator comprises a liquid trap reservoir. ### Claim 30 (depends on 1) An apparatus as in claim 1 further comprising a control system configured to: receive a signal, and based upon the signal, cause a valve to selectively admit compressed gas from a high pressure side into the first cylinder to drive the first piston to cause an electrical generator to supply electrical power through an interface to a power supply network over a ramp up period of a generation asset. ### Claim 31 (depends on 30) An apparatus as in claim 30 wherein the interface is selected from a meter, a busbar, or a transformer. ### Claim 32 (depends on 1) An apparatus as in claim 1 further comprising an insulated tank storing the first liquid. ### Claim 33 (depends on 1) An apparatus as in claim 1 wherein the element is configured to effect heat exchange across a gas-liquid interface having a ratio of surface area (m2): number of moles of gas, of between about 1-200. ### Claim 34 An apparatus comprising: a first cylinder configured to receive a first piston; a first liquid including a foaming agent; a first element configured to effect heat exchange between the first liquid and gas expanding against the piston; a first mechanical linkage configured to transmit from the first cylinder, a power of the gas expanding against the first piston in an expansion mode; and a first separator configured to receive an expanded gas-liquid mixture in the expansion mode, wherein in a compression mode the first mechanical linkage is in selective communication with a first source of shaft torque to cause the first piston to compress gas in the first cylinder while the first element effects heat exchange between the first liquid and gas being compressed within the first cylinder, the apparatus further including a low pressure stage in selective fluid communication with the first cylinder and comprising: a second cylinder configured to receive a second piston; a second liquid; a second element configured to effect heat exchange between the second liquid and gas expanding against the second piston; a second mechanical linkage configured to transmit from the second cylinder to the electrical generator, a power of the gas expanding against the second piston in an expansion mode; and a second separator configured to receive an expanded gas-liquid mixture from the second cylinder in the expansion mode, wherein in a compression mode the second mechanical linkage is in selective communication with the source of shaft torque to cause the second piston to compress gas in the second cylinder while the second element effects heat exchange between the second liquid and gas being compressed within the second cylinder. ### Claim 35 (depends on 34) An apparatus as in claim 34 wherein the second mechanical linkage comprises a second piston rod and a second cross-head. ### Claim 36 (depends on 34) An apparatus as in claim 34 wherein the second element comprises a sprayer. ### Claim 37 (depends on 36) An apparatus as in claim 36 wherein the sprayer is in fluid communication with the second cylinder. ### Claim 38 (depends on 36) An apparatus as in claim 36 wherein the sprayer is in fluid communication with a mixing chamber.