Thermal energy storage system

• US 8,851,066 B1
• Filed: 04/01/2010
• Issued: 10/07/2014
• Est. Priority Date: 04/01/2009
• Status: Active Grant

• Current Assignee: Kelvin L. Kapteyn
• Original Assignee: Kelvin L. Kapteyn
• Inventors: Kapteyn, Kelvin L.
• Primary Examiner(s): Schneider, Craig
• Assistant Examiner(s): PRICE, CRAIG JAMES
• Application Number:
  US12/752,421
• Time in Patent Office: 1,650 Days
• Field of Search: 126/48.2, 126/569, 126/617, 126/620, 126/634, 126/636, 126/643, 126/678, 126/709
• US Class Current: 126/620
• CPC Class Codes: F24S 23/74 with trough-shaped or cylindro-parabolic reflective surfaces
• CPC Class Codes: F24S 60/00 Arrangements for storing heat collected by solar heat collectors working fluids forming pools or ponds F24S10/10
• CPC Class Codes: F28D 20/0034 using liquid heat storage material
• CPC Class Codes: F28D 20/0056 using solid heat storage material F28D20/0052 takes precedence
• CPC Class Codes: F28D 2020/0078 Heat exchanger arrangements
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 60/14 Thermal energy storage
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

A thermal energy storage system includes fluid conduits disposed in a loose solid material. The loose solid material may be disposed inside a waterproof barrier, and the fluid conduits may be configured to define a plurality of zones having different temperatures in operation. The system may include a solar collector or other source of heated oil or other fluid that is routed to the thermal energy storage unit and/or an energy-consuming facility.

Claims

1. A thermal energy system, comprising:

at least one source of thermal energy providing heated oil at a first temperature that is substantially greater than an ambient air temperature;

at least one energy-consuming unit that consumes thermal energy transported to the energy-consuming unit by heated oil;

at least one thermal energy storage unit having a thermal mass that selectively receives and releases thermal energy that is transported to and from the thermal mass by oil;

a fluid conduit system fluidly interconnecting the source of thermal energy, the energy-consuming unit, and the thermal energy storage unit and providing flow of oil between the source of thermal energy, the energy-consuming unit and the thermal energy storage unit;

a control system configured to control flow of oil through the fluid conduit system according to predefined criteria; and

wherein

the one thermal energy storage unit comprises a waterproof barrier defining an interior space, and including substantially loose solid material disposed in the interior space, and at least one fluid conduit extending through the loose solid material to transfer thermal energy from oil flowing through the at least one fluid conduit to the loose solid material.

2. The thermal energy system of claim 1, wherein:

at least some oil disposed in the one fluid conduit in the one thermal energy storage unit is at a temperature that is significantly greater than 212°

F.

3. The thermal energy system of claim 1, wherein:

the loose solid material disposed in the interior space defines a first thermal mass, and oil disposed in the one fluid conduit in the interior space defines a second thermal mass, and wherein the second thermal mass is no more than 10% of the sum of the first and second thermal masses.

4. The thermal energy system of claim 3, wherein:

the second thermal mass is no more than 1% of the first and second thermal masses.

5. The thermal energy system of claim 1, wherein:

the loose solid material comprises sand.

6. The thermal energy system of claim 1, wherein:

the loose solid material comprises gravel.

7. The thermal energy system of claim 1, wherein:

the loose composite material comprises dirt.

8. The thermal energy system of claim 1, wherein:

the source of thermal energy comprises a plurality of solar collectors having elongated conduits carrying oil therethrough.

9. The thermal energy system of claim 1, wherein:

the one thermal energy storage unit has a sloped upper surface; and

wherein the source of thermal energy comprises a plurality of elongated solar collectors disposed on the sloped upper surface.

10. The thermal energy system of claim 1, wherein:

the source of thermal energy comprises a geothermal system.

11. The thermal energy system of claim 1, wherein:

the control system is configured to cause some heated oil from the source of thermal energy to flow to the energy-consuming unit while substantially simultaneously causing some heated oil from the source of thermal energy to flow to the thermal energy storage unit if an amount of thermal energy produced by the source of thermal energy exceeds an amount of thermal energy consumed by the energy-consuming unit.

12. The thermal energy system of claim 1, wherein:

the control system is configured to route heated oil from the source of thermal energy to the energy-consuming unit if predefined operating criteria exist.

13. The thermal energy system of claim 12, wherein:

the predefined operating criteria comprises a temperature of heated oil exiting the source of thermal energy at a predefined minimum temperature.

14. The thermal energy system of claim 1, wherein:

the loose solid material disposed in the interior space defines at least first and second zones and first and second temperatures corresponding to the first and second zones, respectively;

the one fluid conduit disposed in the interior space includes a first section of fluid conduit disposed in the first zone and fluidly connected to a first inlet port and a first outlet port;

the one fluid conduit disposed in the interior space further including a second section of fluid conduit disposed in the second zone and fluidly connected to a second inlet port and a second outlet port; and

wherein the control system controls flow of heated oil from the source of thermal energy through the first and second section of fluid conduit based, at least in part, on the first and second temperatures.

15. The thermal energy system of claim 14, including:

an insulating barrier comprising substantially solid material extending between the first and second zones and thermally isolating the first and second zones from each other.

16. The thermal energy system of claim 15, wherein:

the first and second zones comprise horizontally elongated volumes.

17. The thermal energy system of claim 16, wherein:

the first zone comprises a center zone and the second zone substantially surrounds the first zone.

18. The thermal energy system of claim 17, wherein:

the first zone has a generally cylindrical outer boundary, and the first section of fluid conduit comprises a plurality of generally parallel first tube sections; and

the second zone has cylindrical inner and outer boundaries and a plurality of generally parallel second tube sections disposed between the inner and outer boundaries.

19. The thermal energy system of claim 18, wherein:

the parallel first tube sections are spaced-apart from one another at approximately equal distances; and

the parallel second tube sections are spaced-apart from one another at approximately equal distances.

20. The thermal energy system of claim 18, including:

a first manifold having an inlet port and a plurality of outlet ports fluidly connected to the inlet port, wherein each outlet port is fluidly connected to a first end of each first tube section; and

a second manifold having an outlet port and a plurality of inlet ports fluidly connected to the outlet port, wherein each inlet port is fluidly connected to a second end of each first tube section.

21. The thermal energy system of claim 14, wherein:

in operation, the first and second zones define first and second temperatures, respectively, and wherein the first temperature is significantly greater than the second temperature and wherein the control system is configured to prevent the first temperature from exceeding a predefined maximum temperature of 450°

F., and wherein the second temperature is at least about 250°

F.

22. The thermal energy system of claim 14, wherein:

the control system is configured to direct flow of heated oil from the one source of thermal energy to at least one of the first and second zones only if a temperature of the at least one zone is less than a temperature of heated oil from the one source of thermal energy.

23. The thermal energy system of claim 22, wherein:

in operation, the first zone has a temperature that is significantly greater than a temperature of the second zone; and

the control system is configured to cause heated oil from the one source of thermal energy to flow through the second section of fluid and into the second zone if heated oil from the one source of thermal energy is at a temperature that is greater than a temperature of the second zone, but less than a temperature in the first zone.

24. The thermal energy system of claim 22, wherein:

in operation, the first zone has a temperature that is significantly greater than a temperature of the second zone; and

the control system is configured to direct oil to be heated for use by the energy-consuming unit to the second zone if a temperature of the oil to be heated is less than a temperature of the second zone.

25. The thermal energy system of claim 24, wherein:

the control system is configured to cause oil exiting the second zone to flow through the first zone if a temperature of oil exiting the second zone is less than a minimum temperature.

26. The thermal energy system of claim 25, including:

an auxiliary heat source that utilizes combustion to generate thermal energy; and

wherein the control system causes oil exiting the thermal energy storage unit to be further heated by the auxiliary heat source if a temperature of oil exiting the thermal energy storage unit is less than a minimum temperature.

27. The thermal energy system of claim 25, wherein:

the energy-consuming unit includes a generator that utilizes heated oil from the thermal energy storage unit to create steam that drive the generator to generate electricity.

28. The thermal energy system of claim 22, wherein:

the control system is configured to cause oil initially exiting the source of thermal energy to be recirculated back through the source of thermal energy if a temperature of oil initially exiting the source of thermal energy is less than a minimum temperature.

29. The thermal energy system of claim 22, wherein:

the loose solid material of the thermal energy storage unit further defines a third zone having a third section of fluid conduit disposed therein;

the control system is configured to cause heated oil from the source of thermal energy to flow through the first zone and be returned to the source of thermal energy without flowing through the second and third zones if first operating conditions occur;

the control system is configured to cause heated oil from the source of thermal energy to flow through the first and second zones before the oil is returned to the source of thermal energy if second operating conditions occur; and

the control system is configured to cause heated oil from the source of thermal energy to flow through the first, second, and third zones if third operating conditions occur.

30. The thermal energy system of claim 29, wherein:

the source of thermal energy comprises a solar collector.

31. The thermal energy system of claim 30, wherein:

the source of thermal energy further comprise a heater that utilizes combustion of fuel to generate heat.

32. A thermal energy storage unit, comprising:

a volume of substantially loose solid material, the volume defining first and second zones having first and second temperatures;

a first fluid conduit section disposed in the first zone, the first fluid conduit section having a first inlet and a first outlet;

a second fluid conduit section disposed in the second zone, the second fluid conduit section having a second inlet and a second outlet; and

a control system configured to control flow of fluid through the first and second fluid conduit sections based, at least in part, on the first and second temperatures, and wherein the control system is configured to cause fluids entering the thermal energy storage unit to flow through only a selected one of the first and second zones before exiting the thermal energy storage unit if predefined operating criteria are satisfied.

33. The thermal energy storage unit of claim 32, including:

oil disposed in at least one of the first and second fluid conduit sections.

34. The thermal energy storage unit of claim 33, including:

a solar collector fluidly connected to the first and second fluid conduit sections.

35. The thermal energy storage unit of claim 32, wherein:

the volume of substantially loose solid material is disposed inside a waterproof barrier.

36. The thermal energy storage unit of claim 35, including:

a layer of insulating material extending between the first and second zones.

37. The thermal energy storage unit of claim 32, wherein:

the control system is configured to cause fluid entering the thermal energy storage unit to flow through both the first and second zones.