# US 12,193,330 B2 · Energy storage systems and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,193,330 B2 - Document ID: US12193330B2 - Status: Granted - Kind: B2 - Application number: 17/201,679 - Filed: 2021-03-15 - Published: 2022-09-15 - Granted: 2025-01-07 - Earliest claimed: 2021-03-15 - Assignees: One Power Company - Applicants: One Power Company - Inventors: Jereme Kent; Amir Sohrabi Mollayousef - Web page: https://patentgrep.com/patent/US12193330B2 ## CPC - H10N 10/13: characterised by the heat-exchanging means at the junction - F28D 20/0034: {using liquid heat storage material} - F28D 20/0052: {using the ground body or aquifers as heat storage medium} - H02N 11/002: {Generators} - H10N 10/17: characterised by the structure or configuration of the cell or thermocouple forming the device - F28D 2020/0078: {Heat exchanger arrangements} - Y02E 60/14: Thermal energy storage - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general) - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The technical description relates to energy storage systems and methods. Specific examples described herein relate to in-ground energy storage systems and methods of selectively discharging electrical energy from an energy storage system. An example energy storage system comprises a first fluid storage tank, a second fluid storage tank, a first fluid disposed in the first fluid storage tank, a second fluid disposed in the second fluid storage tank, a heating unit operably connected to the first fluid storage tank and adapted to heat the first fluid, a cooling unit operably connected to the second fluid storage tank and adapted to cool the second fluid, and an energy conversion unit exposed to the first fluid and the second fluid. The energy conversion unit is adapted to convert a temperature difference between the first fluid and the second fluid directly to electrical energy or indirectly to electrical energy through intermediate mechanical work, such as rotational motion. ## Claims ### Claim 1 An energy storage system, comprising: a first in-ground fluid storage tank defining a first chamber; a second in-ground fluid storage tank defining a second chamber; a first fluid disposed in the first chamber; a second fluid disposed in the second chamber; a heating unit operably connected to the first in-ground fluid storage tank and adapted to heat the first fluid; a cooling unit operably connected to the second in-ground fluid storage tank and adapted to cool the second fluid; and a thermoelectric generator exposed to the first fluid and the second fluid and adapted to convert a temperature difference between the first fluid and the second fluid directly to electrical energy. ### Claim 2 (depends on 1) The energy storage system of claim 1, wherein the first fluid and the second fluid are the same. ### Claim 3 (depends on 2) The energy storage system of claim 2, wherein the first fluid and the second fluid comprise water. ### Claim 4 (depends on 1) The energy storage system of claim 1, wherein the first in-ground fluid storage tank and the second in-ground fluid storage tank have the same dimensions. ### Claim 5 (depends on 1) The energy storage system of claim 1, wherein at least one of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 5 times a depth of the in-ground fluid storage tank. ### Claim 6 (depends on 1) The energy storage system of claim 1, wherein at least one of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 10 times a depth of the in-ground fluid storage tank. ### Claim 7 (depends on 1) The energy storage system of claim 1, wherein at least one of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 20 times a depth of the in-ground fluid storage tank. ### Claim 8 (depends on 1) The energy storage system of claim 1, wherein the first in-ground fluid storage tank and the second in-ground fluid storage tank have the same dimensions; and wherein each of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 5 times a depth of the in-ground fluid storage tank. ### Claim 9 (depends on 1) The energy storage system of claim 1, wherein the first in-ground fluid storage tank and the second in-ground fluid storage tank have the same dimensions; and wherein each of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 10 times a depth of the in-ground fluid storage tank. ### Claim 10 (depends on 1) The energy storage system of claim 1, wherein the first in-ground fluid storage tank and the second in-ground fluid storage tank have the same dimensions; and wherein each of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 20 times a depth of the in-ground fluid storage tank. ### Claim 11 (depends on 1) The energy storage system of claim 1, wherein the heating unit comprises an electrical induction heater partially disposed in ground adjacent the first in-ground fluid storage tank and having a heating coil disposed within the first chamber and in contact with the first fluid. ### Claim 12 (depends on 11) The energy storage system of claim 11, further comprising a second heating unit partially disposed in ground adjacent the first in-ground fluid storage tank and having a second heating coil disposed in the first chamber and in contact with the first fluid. ### Claim 13 (depends on 1) The energy storage system of claim 1, wherein the cooling unit comprises an electric refrigeration unit disposed in ground adjacent the second tank and having a cooling coil disposed in the second chamber and in contact with the second fluid. ### Claim 14 An energy storage system, comprising: a first in-ground fluid storage tank having a first cover and defining a first chamber; a second in-ground fluid storage tank having a second cover and defining a second chamber; a first fluid disposed in the first chamber; a second fluid disposed in the second chamber; a heating unit partially disposed in ground adjacent the first in-ground fluid storage tank and having a heating coil disposed within the first chamber and in contact with the first fluid; a cooling unit disposed in ground adjacent the second in-ground fluid storage tank and having a cooling coil disposed in the second chamber and; and a thermoelectric generator exposed to the first fluid and the second fluid and adapted to convert a temperature difference between the first fluid and the second fluid directly to electrical energy. ### Claim 15 (depends on 14) The energy storage system of claim 14, wherein the first fluid and the second fluid comprise water. ### Claim 16 (depends on 15) The energy storage system of claim 15, wherein the first in-ground fluid storage tank and the second in-ground fluid storage tank have the same dimensions. ### Claim 17 (depends on 16) The energy storage system of claim 16, wherein at least one of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 5 times a depth of the in-ground fluid storage tank. ### Claim 18 (depends on 16) The energy storage system of claim 16, wherein at least one of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 10 times a depth of the in-ground fluid storage tank. ### Claim 19 (depends on 16) The energy storage system of claim 16, wherein at least one of the first in-ground fluid storage tank and the second in-ground fluid storage tank has at least one of a length and a width that is at least 20 times a depth of the in-ground fluid storage tank. ### Claim 20 (depends on 1) The energy storage system of claim 1, wherein the first in-ground fluid storage tank comprises a first bottom and a first sidewall; wherein the second in-ground fluid storage tank comprises a second bottom and a second sidewall; and wherein the first and second bottom and the first and second sidewall are exposed to the earth.