# US 2013/0152578 A1 · Power generation system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0152578 A1 - Document ID: US20130152578A1 - Status: Published application - Kind: A1 - Application number: 13/818,221 - Filed: 2011-08-29 - Published: 2013-06-20 - Earliest claimed: 2010-08-31 - Assignees: Yellow Shark Holding Aps - Inventors: Sigurd Solem - Web page: https://patentgrep.com/patent/US20130152578A1 ## CPC - F01K 25/02: the fluid remaining in the liquid phase - F01K 25/10: the vapours being cold, e.g. ammonia, carbon dioxide, ether - F03G 4/02: with direct {working} fluid contact - F03G 4/029: {closed loop geothermal collectors, i.e. the fluid is pumped through a closed loop in heat exchange with the geothermal source, e.g. via a heat exchanger} - F03G 7/06112: {using the thermal expansion or contraction of enclosed fluids} - Y02E 10/10: Geothermal energy - 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) - F03G: SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR (arrangements in connection with power supply in vehicles from force of nature B60K16/00; electric propulsion with power supply in vehicles from force of nature B60L8/00) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A power generation system in which a thermally expandable fluid, e.g., R134a, CO2, is circulated in a loop between a first location and a second location, the second location being at a higher elevation than the first location. The fluid is heated at the first location to expand it, so that it rises to the second location where it is cooled and contracted. The cooled fluid, being denser, then falls back to the first location under hydrostatic pressure, causing a circular fluid flow. This flow is used to generate power in a power transfer system. The system is regulated so that the fluid does not flash to a vapor, i.e., the fluid does not change state, which improves the efficiency of the system. The system is suitable for use in any situation where a height difference exists, and is particularly suited for geothermal heating sources. ## Claims ### Claim 1 A power generation system comprising: a heat source provided at a first location; a heat sink provided at a second location, wherein said second location is elevated relative to said first location; first fluid communication means extending from said heat sink to said heat source; a power transfer system in fluid communication with said heat sink; and second fluid communication means extending from said heat source to said power transfer system, wherein said fluid communication means are operable to circulate a thermally expandable fluid in a loop between said first and second locations, said fluid circulated from said first location, where it is heated and expanded by said heat source, in an upwards direction through said second fluid communication means to said second location, where it passes through said power transfer system and is cooled and contracted by said heat sink, and in a downwards direction through said first fluid communication means back to said first location, the circulation of said fluid operable to drive said power transfer system to generate power, characterised in that said power generation system further comprises a pressure regulation means wherein said regulation means is operable to regulate a pressure difference experienced by the fluid at said power transfer system to prevent said fluid flashing to a vapour. ### Claim 2 (depends on 1) The power generation system of claim 1, wherein said first fluid communication means and said second fluid communication means form a closed fluid communication circuit. ### Claim 3 (depends on 1) The power generation system of claim 1, wherein said power transfer system is provided at said second location. ### Claim 4 (depends on 1) The power generation system of claim 1, wherein said pressure regulation means comprises at least one choke valve. ### Claim 5 (depends on 4) The power generation system of claim 4, wherein at least one choke valve is located at an inlet of said power transfer system, said choke valve operable to regulate the rate of fluid flow into said power transfer system from said second fluid communication means. ### Claim 6 (depends on 4) The power generation system of claim 4, wherein at least one choke valve is located at an outlet of said power transfer system, said choke valve operable to regulate the rate of fluid flow out of said power transfer system for communication to said heat sink. ### Claim 7 (depends on 1) The power generation system of claim 1, any preceding claim, wherein said pressure regulation means is operable to control the operation of said power transfer system to regulate the rate of fluid flow through the power transfer system. ### Claim 8 (depends on 1) The power generation system of claim 1, wherein said power transfer system comprises a volumetric turbine. ### Claim 9 (depends on 1) The power generation system of claim 1, wherein the system further comprises a secondary choke provided in said first fluid communication means, said secondary choke operable to regulate the rate of flow of fluid from said second location to said first location. ### Claim 10 A method for generating power, the method comprising the steps of: (a) heating a thermally expandable fluid at a first location, to convey the relatively lighter heated fluid in an upwards flow direction from said first location; (b) driving a power transfer system using said fluid flow to generate power; (c) cooling said fluid at a second location, said second location elevated relative to said first location, said cooling acting to convey the relatively denser cooled fluid in a downward flow direction from said second location to said first location, and (d) repeating steps (a)-(c) to circulate said fluid in a power generation loop, characterised wherein in that the method further comprises the step of: regulating a pressure difference experienced by the fluid at said power transfer system to prevent said fluid flashing to a vapour.