CLOSED-LOOP, DOME-SHAPED, THERMAL ENERGY STORAGE SYSTEM

Abstract

A thermal energy storage system comprising a dome-shaped thermal storage medium, a power supply that provides electrical power to an electrical air heater, a heat exchanger, an air blower, a steam generator, a tower, and air return duct. The thermal energy storage system may be designed in such a way that air return ducts are used to allow heat to travel back to the thermal storage medium, thereby improving efficiency and reducing loss of heat or energy of the system.

Claims

1. A thermal energy storage system comprising: a thermal storage medium; a power supply that provides electrical power to an electrical air heater; a heat exchanger; an air blower; a steam generator; a tower; and an air return duct.

2. The thermal energy storage system of claim 1, wherein the air blower is a reversible air blower to facilitate direction of heat energy.

3. The thermal energy storage system of claim 1, wherein the power supply comes from a renewable energy source.

4. The thermal energy storage system of claim 3, wherein the renewable energy source comes from solar energy.

5. The thermal energy storage system of claim 1 wherein said heat exchanger is embedded in the thermal repository.

6. A thermal energy storage repository comprising: a thermal storage medium; a thermal insulation layer; an air return duct; an electrical heater; a heat exchanger duct; a central core; a steam generator; an air blower; an impermeable membrane; a power supply; a pipe carrying pressurized steam to turbine or industrial process.

7. The thermal energy storage repository of claim 6, wherein the thermal energy storage medium is dome-shaped.

8. The thermal energy storage repository of claim 6, wherein said heat exchanger is embedded in the thermal repository.

9. The thermal energy storage repository of claim 6, wherein the air blower is reversible to facilitate direction of heat flow.

10. The thermal energy storage repository of claim 6, wherein the power supply comes from a wind.

11. The thermal energy storage repository of claim 6, wherein the power supply comes from solar.

12. The thermal energy storage repository of claim 6, wherein the air blower, electrical heater, and steam generator are horizontally positioned in the heat exchanger duct.

13. The thermal energy storage method of claim 1, wherein said heat exchanger duct is vertically embedded in the thermal repository and said heat exchanger duct is centrally located in said thermal repository.

14. A thermal energy storage method comprising: predetermining a threshold in which renewable energy source is sufficient to charge a thermal energy storage system; determining if there is renewable energy source available that meets the predetermined threshold; using renewable energy source to power an electrical heater; heating air in the center of an energy storage repository; turning of an air blower to store energy for the thermal energy storage system; reversing the air blower and heating steam in a steam generator.

15. The thermal energy storage method of claim 14, further comprising discharging the steam to one or a plurality of other industrial processes.

16. The thermal energy storage method of claim 14, wherein if there is not sufficient renewable energy source available that meets the predetermined threshold, the electrical heater is not powered.

17. The thermal energy storage method of claim 14, further comprising adjusting the speed of the air blower.

18. The thermal energy storage method of claim 14, further comprising adjusting the rate of heating the steam in the steam generator.

19. The thermal energy storage method of claim 15, wherein said one or a plurality of other industrial processes comprise turning a steam turbine and district heating.

20. The thermal energy storage method of claim 15, further comprising re-determining if there is renewable energy source available that meets the predetermined threshold subsequent to discharging the steam to one or a plurality of other industrial processes.

21. The thermal energy storage method of claim 14 further including a heat exchanger duct that is vertically embedded in said energy storage repository and said heat exchanger duct is centrally located in said energy storage repository.

22. The thermal energy storage method of claim 14, wherein the air blower, electrical heater, and steam generator are horizontally positioned in the heat exchanger duct.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0010] In the drawings, which are not necessarily drawn to scale, like numerals may describe substantially similar components throughout the several views. Like numerals having different letter suffixes may represent different instances of substantially similar components. The drawings illustrate generally, by way of example, but not by way of limitation, a detailed description of certain embodiments discussed in the present document.

[0011] FIG. 1 is a schematic view of a thermal energy storage system.

[0012] FIG. 2A is a perspective view of a preferred embodiment of a thermal energy storage repository wherein a heat exchanger is horizontally configured.

[0013] FIG. 2B is a top view of a preferred embodiment of a thermal energy storage repository wherein a heat exchanger is horizontally configured.

[0014] FIG. 2C is a profile view a preferred embodiment of a thermal energy storage repository wherein a heat exchanger is horizontally configured.

[0015] FIG. 3A is a top view of another embodiment of a thermal energy storage repository.

[0016] FIG. 3B is a profile view of another embodiment of a thermal energy storage repository.

[0017] FIG. 3C is a side view of another embodiment of a thermal energy storage repository.

[0018] FIG. 4 depicts another embodiment of the present invention.

[0019] FIG. 5 is a flow diagram for a thermal energy storage method.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed method, structure, or system. Further, the terms and phrases used herein are not intended to be limiting, but rather to provide an understandable description of the invention.

[0021] FIG. 1 is an example schematic view of a thermal energy storage system 100. The thermal energy storage system 100 comprises a thermal storage medium 102, a power supply 106 that provides electrical power to an electrical air heater 108, a heat exchanger 105, an air blower 118, a steam generator 110, a compressor 112, a turbine 114, and an air return duct 104. The thermal storage medium 102 may be dome-shaped. Arrows indicate the heat flow direction 120. In one example, in a closed loop system, excess heat may be drawn back to the thermal energy storage system 100 via the blower 118. In this case, the air blower 118 is a reversible air blower. The thermal energy storage system 100 may be designed in such a way that air return ducts 104 are used to allow heat to travel back to the thermal storage medium 102, thereby improving efficiency and reducing loss of heat or energy of the system. The thermal energy storage system 100 may be a closed-loop system. The power supply 106 may come from an outside renewable energy resource; the renewable energy resource may be wind or solar power.

[0022] FIGS. 2A-C show example preferred embodiments of a thermal energy storage repository 200 wherein an air blower 244, an electrical heater 243, and a steam generator 242 are placed in a single heat exchanger duct 238; wherein the heat exchanger duct 238 is horizontally configured. Further, the thermal energy storage repository 200 wherein the air blower 244, the electrical heater 243, and the steam generator 242 are placed in the heat exchanger duct 238; wherein the heat exchanger duct 238 is horizontally configured and the air blower 244, the electrical heater 243, and the steam generator 242 may be radially configured. The air blower 244, electrical heater 243, and steam generator 242 are horizontally positioned in the heat exchanger duct 238. The horizontally configured heat exchanger duct 238 with said parts placed within the heat exchanger duct 238 are positioned in such a way that leads from the center of the repository to its outer periphery thereby reducing the amount of air ductwork required. In one example, the air blow 244 is positioned on the cool side of the loop. A horizontally-oriented steam generator 242 and electrical heater 243 module can be easily withdrawn for repairs. A spare steam generator 242 and electrical heater 243 module may be inserted into the thermal energy storage repository 200, thus greatly improving the utilization factor of the thermal energy storage repository 200. A plurality of horizontally configured heat exchanger ducts 238 may also be used.

[0023] FIG. 2A shows a preferred embodiment of a thermal energy storage repository 200 in the perspective view. FIG. 2B shows a preferred embodiment of a thermal energy storage repository 200 in the top view. FIG. 2C shows a preferred embodiment of a thermal energy storage repository 200 in the profile view as indicated by a cross sectional line 252 with two arrows pointed upwards. The thermal energy storage repository 200 comprises a thermal storage medium 232, a thermal insulation layer 234, a toroidal return duct 236, a heat exchanger duct 238, a central core 240, a steam generator 242, an electrical heater 243, an air blower 244, an air return duct 246, pressurized steam to turbine or other industrial process 248, a power supply 250, and an impermeable membrane 262.

[0024] The thermal energy storage repository 200 may have a radial configuration. The radial configuration helps with storing energy as heat radiates outward from the center. In particular, the thermal energy storage repository may be dome-shaped, tapered or conical-shaped due to the radial configuration. The dome or conical-shaped thermal energy storage repository 200 is advantageous due to buoyant hot air rising to the top of the thermal storage medium 232 where it is immobilized by the impermeable membrane 262. The heat is retained by the thermal insulation layer 234. The thermal energy storage repository 200 may also be closed-loop and thereby improving energy efficiency.

[0025] In another example, the thermal energy storage repository 200 may also take on spherical configuration which may improve efficiency at retaining heat. The thermal storage medium 232 may be a porous particle bed wherein the porous particle bed may be comprised of granite gravel. The thermal storage medium 232 may also comprised of other material or combinations of materials resulting in a porous particle. In one example, the thermal storage medium is made of granite gravel having 5 cm diameter particles. In yet other examples, the particles may be greater than or less than 5 cm in diameter. The said particles may take on a spherical, oval, toroidal, or a combination thereof.

[0026] The thermal insulation layer 234 comprises materials suitable to provide further insulation and thereby helps to retain the buoyant hot air rising. The thermal insulation layer 234 may comprise of different material composition. In one example, the thermal insulation layer 234 has a fiberglass layer positioned on top and a fine silty sand layer positioned at the bottom. In another example, the thermal insulation layer 234 has a fiberglass layer positioned on the interior side and a fine silty sand layer positioned on the exterior side.

[0027] The toroidal return duct 236 may be positioned interior with respect to the thermal insulation layer 234. The toroidal return duct 236 may be made of concrete, firebrick, or clay. In one example, the toroidal return duct 236 comprises compositions from any two of the concrete, firebrick, or clay material. In another example, the toroidal return duct 236 comprises concrete, firebrick, and clay. It is noted that the combination of compositions that make up the toroidal return duct 236 may combine in a homogenous manner due to individual materials mixing well together. However, the toroidal return duct 236 may also comprise regions of individual compositions making up the entirety of the toroidal return duct 236. The heat exchanger duct 238 may be made of material that can withstand temperature up to 500° C. In one example, the heat exchanger duct 238 is made of stainless steel. The central core 240 may be either an open duct or a vertically-oriented column of large sized particles to allow for enhanced air flow. Central core 240 may have low permeability. In one example, central core 240 is perforated for radial air flow into the thermal storage medium 232; wherein central core 240 takes on a plate-steel structure. In another example, central core 240 may comprise of a refractory brick withstanding a maximum temperature of 800° C.

[0028] Steam generator 242 and electrical heater 243 module may be a standard pipe heater exchanger, resistance heater, microwave, or similar heater. The steam generator 242 and electrical heater 243 module may withstand a maximum temperature of 1100° C. The air blower 244 is reversible and may be made from standard equipment from the power industry. The air blower 244 may withstand temperatures of up to 500° C. The air return duct 246 may be made of stainless steel. In other examples, the air return duct 246 may also be made of standard equipment from the power industry. The pressurized steam to turbine or other industrial process 248 is transported using standard stainless-steel steam pipes with fiberglass insulation. The pipes may be able to withstand a maximum temperature of 600° C. The impermeable membrane 262 may be made of fiberglass cloth. The impermeable membrane 262 may be made of other insulating material. The member may withstand a maximum temperature of 800° C. The power supply 250 may be interchangeably referred to as the electrical supply may come from a high-voltage transmission line. In one example, the power supply 250 comes from renewable resources. The said renewable resource may further come from solar, wind, or hydro or a combination thereof.

[0029] FIGS. 3A, 3B and 3C show another embodiment of a thermal energy storage repository 300 with FIG. 3A in the perspective view while FIG. 3B in the profile view and FIG. 3C is the side view. It should be noted that components previously presented elsewhere may be similarly presented in FIGS. 3A and 3B.

[0030] The thermal energy storage repository 300 comprises a thermal storage medium 332, a thermal insulation layer 334, a steam generator 344, an electrical heater 340, an air blower 342, an air return duct 346, pressurized steam to turbine or other industrial process 348, a power supply 350, and an impermeable membrane 362.

[0031] Additionally, the thermal energy storage repository 300 may further comprise a toroidal return duct, a central core, and a heat exchanger duct which are not shown in FIGS. 3A and 3B but are show in FIG. 2B, for example. Notably, the examples in FIGS. 3A and 3B show embodiments of a thermal energy storage repository 300 wherein an air blower 312, an electrical heater 310, and a steam generator 314 are placed in a single heat exchanger duct; wherein the heat exchanger duct is vertically configured, embedded in the thermal repository and may be central located in the repository.

[0032] The thermal energy storage repository 300 may have a radial configuration. The radial configuration helps with storing energy has heat radiates outward from the center. In particular, the thermal energy storage repository may be dome-shaped, tapered or conical-shaped due to the said radial configuration. The dome or conical-shaped thermal energy storage repository 300 is advantageous due to buoyant hot air rising to the top of the thermal storage medium 332 where it is immobilized by the impermeable membrane 362. The heat is retained by the thermal insulation layer 334. The thermal energy storage repository 300 may also be closed-loop and thereby improving energy efficiency.

[0033] In another example, the thermal energy storage repository 300 may also take on spherical configuration which theoretically may improve efficiency at retaining heat.

[0034] The thermal storage medium 332 may be a porous particle bed wherein the porous particle bed may comprise of granite gravel. The thermal storage medium 332 may also comprise other material or combination of materials resulting in particle bed being porous. In one example, the thermal storage medium is made of granite gravel having 5 cm diameter particles. In yet other examples, the particles may be greater than or less than 5 cm in diameter. The particles may take on a spherical, oval, toroidal, or a combination thereof.

[0035] The thermal insulation layer 334 comprises materials suitable to provide further insulation and thereby helps to retain the buoyant hot air rising. The thermal insulation layer 334 may comprise of different material composition. In one example, the thermal insulation layer 334 has a fiberglass layer positioned on top and a fine silty sand layer positioned at the bottom. In another example, the thermal insulation layer 334 has a fiberglass layer positioned on the interior side and a fine silty sand layer positioned on the exterior side.

[0036] The toroidal return duct may be positioned interior with respect to the thermal insulation layer 304. The toroidal return duct may be made of concrete, firebrick, or clay. In one example, the toroidal return duct comprises compositions from any two of the concrete, firebrick, or clay material. In another example, the toroidal return duct comprises concrete, firebrick, and clay. It is noted that the combination of compositions that make up the toroidal return duct may combine in a homogenous manner due to individual materials mixing well together. However, the toroidal return duct may also comprise regions of individual compositions making up the entirety of the toroidal return duct. The heat exchanger duct may be made of material that can withstand temperature up to 500° C. In one example, the heat exchanger duct is made of stainless steel. The central core may be either an open duct or a vertically-oriented column of large sized particles to allow for enhanced air flow. The central core may have low permeability. In one example, the central core is perforated for radial air flow into the thermal storage medium 332; wherein the central core takes on a plate-steel structure. In another example, the central core may comprise of a refractory brick withstanding a maximum temperature of 800° C.

[0037] The steam generator 344 and electrical heater 340 module comprises a standard pipe heater exchanger, resistance heater, microwave, or similar heater. The steam generator 344 and electrical heater 340 module may withstand a maximum temperature of 1100° C. The air blower 312 is reversible and may be made from standard equipment from the power industry. The air blower 342 may withstand temperatures of up to 500° C. The air return duct 302 may be made of stainless steel. In other examples, the air return duct may also be made of standard equipment from the power industry. The pressurized steam to turbine or other industrial process is transported using standard stainless-steel steam pipes with fiberglass insulation. The pipes may be able to withstand a maximum temperature of 600° C. The impermeable membrane 362 may be made of fiberglass cloth. The impermeable membrane 362 may be made of other insulating material. The member may withstand a maximum temperature of 800° C. The power supply 350 may be interchangeably referred to as the electrical supply may come from a high-voltage transmission line. In one example, the power supply 350 comes from renewable resources. The said renewable resource may further come from solar, wind, or hydro or a combination thereof.

[0038] FIG. 4 depicts another embodiment of the present invention concerning a thermal energy storage repository 400 which may have a top or cover 401 that is radial and dome-shaped or conical-shaped. The radial configuration minimizes the surface to volume of the repository which, in turn, reduces heat loss.

[0039] The angled nature of cap 401 reduces the settling of thermal storage medium 402, which may be gravel or other material as described above. Settling is an issue since, as the packed bed expands and shrinks under thermal cycling, it may settle, thus reducing the air voids in the packed bed. Permeable screens 414-416 may be included to prevent gravel from moving from and within the repository 400.

[0040] Also provided is a heat exchanger 406 connected to blower 409 by duct 408. In a preferred embodiment, heat exchanger 406 is embedded within the thermal repository 400. Top 401 and heat exchanger 406 include an insulation barrier 403. An insulated bottom 410 may also be used. Insulation 403 and 410 may be made as described above.

[0041] Duct 407, which may be toroidal, is also in communication with air blower 409 and medium 402 through vents 404 and 405. Thus, in operation, heat is added to the repository by employing blower 409 to conduct air via duct 408 into heat exchanger 406 and then into the thermal storage medium 402. Heat is extracted by reversing the direction of flow of blower 409.

[0042] FIG. 5 is a flow diagram for a thermal energy storage method. In step 502, an amount or threshold of available renewable energy resource is predetermined to be sufficient to charge the thermal energy storage system 100. In step 504, to determine if the amount or threshold of the renewable energy source is reached, an electrical meter may be used. Other sources or meters or sensors may also be used to determine if the threshold has been reached. A person having ordinary skill in the art may be able to discern if the predetermined threshold for available renewable energy source has been reached. In step 506, if it is determined that the available renewable energy source has not reached a predetermined threshold, then the thermal energy storage system 100 is not charged. The method loops back 508 to step 504.

[0043] It is noted that charging of the thermal energy system 100 may refer to powering electrical heater which will heat air blown by the air blower 244 or 312. In step 510, if it is determined that the available renewable energy source has reached a predetermined threshold, the renewable energy source is used to power the electrical heater. In the energy charging step 512, air is heated in the center of the repository 200 or 300 as in step 514. Heating is expanded radially the region of stored heat as thermal charging takes place in step 516. The rate of heating may be adjusted in this step. When energy charging is complete, the method switches to energy storage mode as in step 518. To use the energy stored, energy discharge takes in place in step 520. In this step, the air blower is reversed at 522 and steam is heated in steam generator. The speed of the air blower may be adjusted in this step. The rate of heating may also be adjusted in this step. In step 526, the steam is discharged to steam turbine, district heating, or other industrial processes. Once step 520 is complete, the method loops back to step 504.

[0044] While the foregoing written description enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The disclosure should therefore not be limited by the above-described embodiments, methods, and examples, but by all embodiments and methods within the scope and spirit of the disclosure.