WO2012125974A1

WO2012125974A1 - System and method for storing seasonal environmental energy

Info

Publication number: WO2012125974A1
Application number: PCT/US2012/029538
Authority: WO
Inventors: Eric Joseph GODTLAND; Kent Stewart Udell
Original assignee: Seasonal Energy, Inc.
Priority date: 2011-03-16
Filing date: 2012-03-16
Publication date: 2012-09-20
Also published as: US20130068418A1

Abstract

A thermo siphon vessel for storing and retrieving seasonal energy in the ground, including: a fluid vessel comprising a heat exchange tube and containing a working fluid; a wicking material arranged within the fluid vessel and configured to retain liquid-state working fluid adjacent an inner wall of the heat exchange tube; a fluid level sensor arranged within the fluid vessel and configured to determine the level of liquid-state working fluid therein; and a pump arranged within the fluid vessel and configured to maintain the level of liquid-state working fluid below a threshold level within the fluid vessel.

Description

SYSTEM AND METHOD FOR STORING

SEASONAL ENVIRONMENTAL ENERGY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.

61/453,422, filed 16 MAR 2011, which is incorporated in its entirety by this reference.

[0002] This application is related to U.S. Patent Publication No. 2010/0305918, filed 07 NOV 2008, which is incorporated in its entirety by this reference.

TECHNICAL FIELD

[0003] This invention relates generally to the geothermal heat exchange field, and more specifically to an improved system and method for heating and cooling a structure in the geothermal heat exchange field.

BACKGROUND

[0004] Current geothermal heating and cooling systems cool and/or heat structures, buildings, and other above-ground systems with minimal energy consumption by utilizing a temperature differential between the ground and the environment (above ground). Current systems typically employ heat pumps that take advantage of the substantially constant temperature of the ground at depths greater than approximately 6ft (2m) below grade to source and sink thermal energy necessary to heat and cool the structure, respectively. Building upon these current systems, the present invention is an improved method and system for heating and cooling a structure.

BRIEF DESCRIPTION OF THE FIGURES

[0005] FIGURE 1 is a schematic representation of the system and thermosiphon vessel of the preferred embodiments;

[0006] FIGURE 2 is a schematic representation of data and control signal flow through the system; [0007] FIGURE 3 is a schematic representation of a system for performing one block of the method of the preferred second embodiment;

[0008] FIGURE 4 is a schematic representation of a system for performing a second block of the method;

[0009] FIGURE 5 is a schematic representation of a system for performing a third block of the method;

[0010] FIGURE 6 is a schematic representation of a system for performing a fourth block of the method;

[0011] FIGURE 7 is a schematic representation of the system incorporating a plurality of thermosiphon vessels;

[0012] FIGURE 8 is a plan view of a structure incorporating a first system and a second system to perform the method of the preferred embodiment;

[0013] FIGURE 9 is a schematic representation of a heat exchanger of the heat exchange system;

[0014] FIGURE 10 is a schematic representation of a wicking material of the thermosiphon vessel of the third preferred embodiment;

[0015] FIGURES 11A-11C are schematic representations of first, second, and third variations of a directing geometry of the fluid vessel of the preferred embodiments; and

[0016] FIGURE 12 is a flowchart representation of the method of the second preferred embodiment; and

[0017] FIGURE 13 is a flowchart representation of the method incorporating variations of the second preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following description of the preferred embodiments of the invention is not intended to limit the invention to these preferred embodiments, but rather to enable any person skilled in the art to make and use this invention.

1. System. Method, and Thermosiphon Vessel of the Preferred Embodiments [0019] As shown in FIGURE l, the system 100 for storing seasonal environment energy for temperature regulation of a structure, of the preferred embodiment, includes: a fluid vessel noincluding a heat exchange tube and a bottom, configured to be installed in the ground, and to contain working fluid; a reservoir 180 coupled to the fluid vessel no and configured to store working fluid; a heat exchange system 120 including an indoor heat exchanger 121, configured to communicate thermal energy between working fluid and an interior volume of the structure, and an outdoor heat exchanger 122, configured to communicate thermal energy between working fluid and the environment; and a pump 150 configured to displace fluid from the fluid vessel 110 to the reservoir 180 to maintain the level of liquid-state working fluid below a threshold level within the fluid vessel 110. The pump 150 is configured to operate between: an energy capture mode, wherein the pump 150 displaces liquid-state working fluid from the fluid vessel 110 to a portion of the heat exchange system 120, wherein the heat exchange system 120 communicates thermal energy into the working fluid and the fluid vessel 110 communicates the thermal energy into the ground for storage; and an energy release mode, wherein working fluid is displaced from the fluid vessel 110 to a portion of the heat exchange system 120, wherein the fluid vessel 110 communicates thermal energy stored in the ground into the working fluid and the heat exchange system 120 communicates the thermal energy out of the working fluid.

[0020] The fluid vessel 110, the reservoir 180, the heat exchange system 120, and the pump are preferably fluidly coupled via a fluid routing system 130 including at least one supply line 134 (fluid outlet) and one return line 135 (fluid inlet). As shown in FIGURE 1, the fluid routing system 130 can also include a number of valves 133A-D configured to selectively isolate elements of the system 100. For example, valve 133a can be arranged between a first supply line 134A and the reservoir 180; valve 133B can be arranged between the return line 135 and the indoor and outdoor heat exchangers 121, 122; valve 133C can be arranged between a second supply line 134B and the indoor and outdoor heat exchangers 121, 122; and valve 133D can be arranged between the reservoir 180 and the fluid vessel 110. As shown in FIGURE 2, the system 100 can also include a fluid level sensor 160 configured to determine the level of working fluid within the fluid vessel no, and processor 170 can be configured to control the addition of liquid-state working fluid into the fluid vessel 110 from a reservoir 180 given a substantially low level of working fluid within the fluid vessel 110, or vice versa for a high level of working fluid. As shown in FIGURE 2, the system 100 can also incorporate an external display 190 configured to display, to a user, information regarding operation of the system. The heat exchange system 120 (e.g., within the indoor heat exchange system within the structure) can also include a heat pump 125, wherein the working fluid pumped through or adjacent the heat pump 125 improves the efficiency of the heat pump.

[0021] The system 100 of the preferred embodiment is preferably capable of performing at least a portion of the method Sioo of the second preferred embodiment. As shown in FIGURE 12, the method Sioo for regulating the temperature within a structure with a first thermosiphon array 210 of fluid vessels, installed in the ground proximal the structure, and a second thermosiphon array 220 of fluid vessels, installed in the ground proximal the structure and substantially removed from the first thermosiphon array 210 (shown in FIGURE 8), includes, during a period of substantially high environmental temperatures: generating a thermal hot battery 310 of the ground proximal the first thermosiphon array 210 by directing liquid-state working fluid from the first array of fluid vessels through an outdoor heat exchanger exposed to the environment, wherein working fluid absorbs thermal energy from the environment and releases the thermal energy into the ground, proximal the first thermosiphon array, for storage, block S110, shown in FIGURE 3; and cooling the structure by directing liquid-state working fluid from the second array 220 of fluid vessels through an indoor heat exchanger coupled to the structure, wherein working fluid absorbs thermal energy from the structure and releases the thermal energy into the ground proximal the second thermosiphon array, block S140, shown in FIGURE 6. The method Sioo also includes, during a period of substantially low environmental temperatures (e.g., winter or at night): generating a thermal cold battery of the ground proximal the second thermosiphon array 220 by directing vapor-state working fluid from the second array of fluid vessels through an outdoor heat exchanger exposed to the environment, wherein working fluid absorbs thermal energy from the ground proximal the second thermosiphon array and releases the thermal energy to the environment, block S120, shown in FIGURE 4; and heating the structure by directing working fluid from the first array of fluid vessels 210 through an indoor heat exchanger coupled to the structure, wherein working fluid absorbs thermal energy from the ground proximal the first thermosiphon array and releases the thermal energy into the structure, block S130, shown in FIGURE 5.

[0022] As shown in FIGURE 13, the method S100 may further include: block

S115, wherein generating the thermal hot battery of the ground and cooling the structure comprise actively pumping liquid-state working fluid out of the first array of fluid vessels; and block S125, wherein generating the thermal cold battery of the ground comprises passively pumping vapor-state working fluid out of the second thermosiphon array. Finally, the method S100 may also or alternatively include maintaining the level of liquid-state working fluid within each fluid vessel of the first and second thermosiphon arrays below a threshold level. However, the method S100 may include any other block or process.

[0023] As shown in FIGURES 1, 8, and 12, the system 100 and method S100 of the preferred embodiment preferably apply a geothermal thermosiphon system to generate a thermal battery (310 and/or 320) in the ground proximal the fluid vessel 110, wherein the thermal battery can subsequently be used to regulate the temperature of a volume within the structure. The system 100 preferably implements the thermosiphon vessel 400 of the third preferred embodiment. The thermosiphon vessel 400, for generating a soil-based thermal battery within the ground, includes: a fluid vessel 110 comprising a heat exchange tube 114, configured to contain a working fluid, and further configured to receive a fluid inlet 135 and a fluid outlet 134 (and 134b); a wi eking material 115 arranged within the fluid vessel 110 and configured to retain liquid-state working fluid substantially adjacent an inner wall of the heat exchange tube 114; a fluid level sensor 160 arranged within the fluid vessel 110 and configured to determine the level of liquid-state working fluid therein; and a pump 150 arranged within the fluid vessel 110 and configured to maintain the level of liquid-state working fluid below a threshold level within the fluid vessel 110. The pump 150 is operable between: an energy capture mode, wherein the pump 150 displaces liquid-state working fluid from the fluid vessel 110 to absorb thermal energy from an above-ground heat source, wherein the fluid vessel communicates the thermal energy from the working fluid into the ground for storage; and an energy release mode, wherein working fluid is directed from the fluid vessel 110 to release thermal energy to an above-ground heat sink, wherein the fluid vessel communicates thermal energy stored in the ground into the working fluid. The thermosiphon vessel can further include directing geometry 115 to increase the surface area of the inner wall of the heat exchange tube, or the wicking material 114 can be replaced entirely by the directing geometry 115.

[0024] 'Ground' is herein defined as a land area, body of water, and/or a depth of soil, dirt, rock, or other earth beneath the land area; 'earth,' 'dirt,' and 'soil' can be used interchangeably with 'ground' this application. Furthermore, the system 100 and method S100 of the preferred embodiment are preferably applied to a structure that is a house, a garage, a commercial building, a skyscraper, a docked boat or ship, a sport arena or gymnasium, or any other structure or building in which a user or occupant can desire heating and/or cooling therein.

[0025] Current practice involving ground source heat pumps and geothermal heating and cooling systems rely on substantially consistent ground temperatures at depths greater than approximately 6ft (2m) below grade to regulate the temperature of a building (or agricultural field, generator, etc.). However, the system 100 and method S100 of the preferred embodiment does not rely on the substantially constant temperature of the ground at such depths, but rather seeks to substantially modify the temperature of the ground proximal the fluid vessel 110 in order to a generate a substantially long-term thermal battery (310 or 320). In one variation, the thermal battery is a cold battery 320, wherein, during winter or other substantially cold periods (e.g., at night, late fall, early spring), heat is transferred from the ground proximal the fluid vessel 110 to the air (or other above-ground sink) in order to cool the ground; during summer or other substantially warm periods (e.g., during the day, early fall, late, spring), heat from the building or other structure can be absorbed into the ground proximal the fluid vessel 110 relatively rapidly due to the substantial temperature difference between the cooled ground and the building and/or environment. In a second variation, the thermal battery is a hot battery 310, wherein, during summer or other substantially warm periods, heat is transferred from the air (or other above-ground source, such as a solar panel, panel array, or power facility with waste heat) to the ground proximal the fluid vessel 110 in order to warm the ground. During winter or other substantially cold periods, heat from the ground can be dispensed into the building, structure, to thermoelectric generator relatively rapidly due to the substantial temperature difference between the heated ground and the building, structure, device, and/or environment. Therefore, the system 100 and method S100 of the preferred embodiment function to generate long-term hot and/or cold batteries (310, 320) of a volume of soil for cyclic (e.g., seasonal or daily) temperature regulation of the structure.

[0026] As shown in FIGURES 7 and 8, the system 100 preferably includes a plurality of fluid vessels (e.g., 110B, 110C, 110P) substantially identical to the fluid vessel 110 (each including a pump 150 and other necessary peripherals substantially similar to those of the fluid vessel 110), wherein the fluid vessels are configured for arrangement in the ground in a first thermosiphon array 210. The first thermosiphon array 210 is preferably dedicated to a single thermal battery type and method. Specifically, the first thermosiphon array 210 can either: (1) be dedicated to a cold battery 320 and perform blocks S120 and S140; or (2) be dedicated to a hot battery 310 and perform blocks S110 and S130. The system 100 can further include a second thermosiphon array 220 dedicated to the thermal battery type and blocks not performed by the first thermosiphon array 210. However, any other arrangement of the fluid vessel iio(s) and the thermosiphon array(s) can be used.

[0027] Regardless of the thermal battery type to which the fluid vessel 110 or thermosiphon vessel 400 is dedicated, the system 100 preferably operates between an energy capture mode and an energy release mode. The operation mode of the system 100 is preferably dictated by operation of the pump 150. Generally, the system 100 is in the energy capture mode when the pump 150 is ON and pumping liquid-state working fluid from the fluid vessel 110 to a portion heat exchange system 120, and the system 100 is in the energy release mode when the pump 150 is OFF and vapor-state working fluid is passed to the heat exchanger by the force of gravity. However, the operation mode of the system 100 can additionally or alternatively be dictated by operation of the valves 133. Generally, states of various valves can adjust such that the system 100 is in the energy capture mode when the pump 150 is ON and pumping cooler liquid-state working fluid from the fluid vessel 110 and warmer liquid-state working fluid returns to the fluid vessel 110, and the system 100 is in the energy release mode when the pump 150 is ON and pumping warmer liquid-state working fluid from the fluid vessel 110 and cooler liquid-state working fluid returns to the fluid vessel 110.

[0028] In the energy capture mode, as shown in FIGURES 3 and 6, the pump 150 displaces liquid-state working fluid from the fluid vessel 110 through the fluid routing system 130 toward the heat exchange system 120. Working fluid then absorbs thermal energy from the environment and/or the building, through the outdoor or indoor heat exchangers 122, 121. The working fluid subsequently returns to the fluid vessel via the return line 135 (or the vapor supply line 134b, with vapor leaving the fluid vessel and liquid returning to the fluid vessel via the same line), wherein working fluid sinks the thermal energy through the heat exchange tube 114 and into the ground. This cycle can henceforth be repeated for a volume of working fluid. In the energy capture mode, the working fluid within the fluid routing system 130 preferably remains in the liquid state; consequently, at least a portion of the fluid routing system 130 may be pressurized to prevent vaporization of the working fluid therein. In the energy capture mode, the system 100 can generate a hot battery 310 of the ground (block S110), such as in summer with working fluid passing through the outdoor heat exchanger 122. Alternatively, the system 100 can cool the building (block S140) via a thermal cold battery 320, such as in summer with liquid-state working fluid passing through the indoor heat exchanger 121 to collect thermal energy therefrom.

[0029] In the energy release mode, as shown in FIGURES 4 and 5, working fluid absorbs thermal energy from the ground, via the heat exchange tube 114 of, which substantially vaporizes working fluid; vapor-state working fluid then passes through the supply line 134b to the heat exchange system 120 where thermal energy is deposited (e.g., released to the environment or into the building), which substantially condenses working fluid; the liquid working fluid then travels through the fluid routing system 130 (preferably the outer fluid path 131 thereof) to return to the fluid vessel 110, wherein the cycle can be subsequently repeated for the volume of working fluid. In this mode, the system 100 can generate a cold battery 320 of the ground (block S120), such as in winter with working fluid passing through the outdoor heat exchanger 122 of the heat exchange system 120. Alternatively, the system 100 can heat the building (block S130) via a thermal hot battery 310, such as in winter with warm working fluid passing through the indoor heat exchanger 121 of the heat exchange system 120.

[0030] Because displacement of the fluid in the energy capture mode (blocks S110 and S140) requires a pump 150 or other active displacement means and because displacement of the fluid in the energy release mode (blocks S120) occurs naturally (due to gravity), the energy release mode can be descriptive of a passive heat exchange system and the energy capture mode (blocks S110 and S140) can be descriptive of an active heat exchange system. The system 100 of the preferred embodiment can switch between the energy release and energy capture modes depending on preferences of a user (e.g., desired indoor temperature), the indoor or outdoor temperature, the time of day, the time of year, the season, the thermal battery type to which the fluid vessel 110 is dedicated, or any other suitable factor.

[0031] In the variation of the system 100 configured to create a thermal hot battery, the working fluid preferably remains in liquid form throughout operation of the system 100. Generally, the pump 150 can displace liquid-state working fluid to the outdoor heat exchanger 122, in blocks S110 and S120, wherein the working fluid returns to the fluid vessel 110 either hotter or colder but still in the liquid state, and the pump can displace liquid-state working fluid to the indoor heat exchanger to absorb or release thermal energy from or into the interior volume of the structure, in blocks S130 and S140, wherein the working fluid returns to the fluid vessel 110 either hotter or colder but still in the liquid state. When working fluid gains thermal energy before returning to the fluid vessel 110, the working fluid preferably does not transition from the liquid state to the vapor state, as such phase change can cause cavitation or otherwise impede fluid flow through the fluid routing system 130. Portions of the fluid routing system S130, such as a return line 135 from either the indoor or outdoor heat exchangers 121, 122, can be pressurized to reduce and/or eliminate vaporization of working fluid in the heat exchange system 120 and/or the fluid routing system 130. In this variation, the working fluid is preferably water, through alternative suitable working fluids can include R-i34a refrigerant, ammonia, carbon dioxide, ethanol, a water-glycol mixture, and/or any other suitable type of refrigerant or fluid with substantially high thermal capacity.

[0032] The elements of the system 100, including the fluid vessel 110, the heat exchanger, fluid routing system 130, and the pump 150, are preferably substantially sealed to prevent leakage of working fluid therefrom. These elements are also preferably substantially resistant to degradation in the presence of working fluid. In a first example of the variation of the fluid vessel 110 that is steel, the internal surfaces thereof are nickel-plated to resist corrosion by working fluid that is R-i34a refrigerant. In a second example of a variation of the fluid vessel 110 that is aluminum with steel fittings, a zinc (sacrificial) anode is coupled to the fluid vessel 110 to substantially prevent galvanic corrosion of the heat exchange tube 114 in the presence of working fluid that is water. However, the longevity and safety of the system 100 can be improved by any other suitable technique, material(s), or manufacturing method.

2, Fluid Vessel

[0033] The fluid vessel 110 of the preferred embodiments functions to contain working fluid and to communicate thermal energy between the working fluid and the ground proximal the fluid vessel 110. As shown in FIGURE 1, the heat exchange tube 114 is preferably defined by a heat exchange tube 114, the bottom of the fluid vessel 110 is defined by an integration cap 111, and the top of the fluid vessel 110 is defined by an interface cap 112. The heat exchange tube 114 functions as the primary heat path between working fluid and the ground proximal the fluid vessel 110, the integration cap 111 retains the pump 150, and the interface cap 112 interfaces with at least a portion of the fluid routing system 130. The fluid vessel 110 is preferably configured to be installed in the ground, wherein at least a majority of the fluid vessel 110 is arranged below grade, as shown in FIGURES 1-7. However, the fluid vessel 110 can be arranged above and/or below ground, within a volume of water (e.g., a pond or reservoir 180), within a salt solution, or within any other suitable thermal volume.

[0034] The fluid vessel 110 is preferably configured to be installed in the ground via a direct-push method, wherein sections of hollow steel tube are driven into the ground, the fluid vessel 110 is inserted into the hollow steel tubes, and the hollow steel tubes are removed from the ground. The heat exchange tube 114 is therefore preferably of a material and geometry capable of withstanding the forces associated with direct- push installation. Specifically, the fluid vessel 110 is preferably capable of withstanding circumferential forces (e.g., hoop stress) imparted on the fluid vessel 110 by the ground surrounding the fluid vessel 110 at all depths thereof. The fluid vessel 110 is also preferably capable of withstanding high internal pressures in the variation in which the system 100 is pressurized, such as the variation in which the working fluid is R-i34a refrigerant. Therefore, the fluid vessel 110 is preferably configured to withstand positive and negative circumferential pressures at all depths of installation in the ground and for all working pressures within the system. In a first example, the heat exchange tube 114 is a high-density polyethylene (HDPE) tube with a .25m (6.4mm) wall thickness and 2in (51mm) outer diameter. In a second example, the heat exchange tube 114 is an aluminum tube with a .50m (13mm) wall thickness and a 31η (76mm) inner diameter and includes strengthening ribs running along the inner surface of the heat exchange tube 114. However, the components of the fluid vessel 110 can provide any other functionalities and be of any other material or geometry.

[0035] In the variation in which the fluid vessel 110 is installed in the ground, the heat exchange tube 114 is preferably substantially straight and circular in cross-section with a substantially minimal diameter (e.g., 21η outer diameter) to decrease cost of installation in the ground. The wall of the heat exchange tube 114 is also preferably thin to minimize thermal resistance but thick enough to resist buckling, blow out, or other failure during installation and pressurized usage. The heat exchange tube 114 is also preferably of a material: with a substantially high thermal conductivity, such as copper or aluminum or chemically-augmented HDPE formulations; of a substantially high modulus of elasticity to substantially reduce the risk of buckling during installation, such as steel; and substantially flexible to absorb shifts in the ground, such as due to an earthquake or ground settling, without failure, such as HDPE. The heat exchange tube 114 is also preferably substantially simply constructed. Generally, the heat exchange tube 114 can be a metal or plastic extrusion or of any other suitable material, though the tube 114 can alternatively be molded, cast, rolled and welded, or constructed using any other suitable manufacturing process. The heat exchange tube 114 can alternatively be a composition of various materials, such as an extruded HDPA tube with a Kevlar wrapping along the length thereof or a PVC tube with forged steel strengthening hoops spaced at even intervals there around. However, the heat exchange tube 114 can be of a single material or composition of various materials and can be of any other suitable diameter, cross-section, or geometry. Furthermore, the heat exchange tube 114 can be a singular tube, but alternatively can include multiple sections, joined by a coupler, which may facilitate transportation of the fluid vessel 110 to the install site and may ease installation.

[0036] Because working fluid can be in either a vapor state and/or a liquid state at any given time, the fluid vessel 110 is preferably able to withstand varying fluid pressures associated with varying states of working fluid. The other elements of the system 100, including the heat exchange system 120, the fluid routing system 130, the reservoir 180, and the pump 150 are also preferably able to withstand such fluctuations in fluid pressure over a substantial period of time (e.g., 25 years or more) without failure.

[0037] The integration cap 111 can be physically coextensive with or permanently joined to the heat exchange tube 114. The interface cap 112 can be physically coextensive with the heat exchange tube 114 but is preferably removably (i.e. transiently) assembled at the top of the heat exchange tube 114. Standard fasteners (e.g., nuts and bolts), adhesives, mating threads, plastic heat welding, or any other suitable feature, method, or system can be used to join the integration cap 111 and/or the interface cap 112 to the heat exchange tube 114. However the cap(s) 111, 112 can alternatively be mated to the heat exchange tube 114 via a friction or interference fit, by welding, bonding, or other permanent assembly means. Alternatively, the cap(s) 111, 112 can be manufactured in situ with the heat exchange tube 114. The integration cap 111 preferably retains the pump 150, though the pump can alternatively be supported by a portion of the heat exchange tube 114. The interface cap 112 can include control electronics necessary for operation of the pump 150 and any electronic devices arranged within the fluid vessel 110, such as a temperature sensor, the fluid level sensor 160, solenoid valves, or a pressure sensor. Alternatively, the interface cap 112 can interface with electrical connectors (e.g., quick-disconnect electrical connectors or pressure vessel electrical penetrations) or be coupled to such electrical components, which may facilitate assembly of the system 110 for installations with multiple fluid vessels and a central control unit (i.e., the processor 170).

[0038] The fluid vessel 110 is preferably modular, wherein the fluid vessel 110 can be simply assembled during installation, and wherein certain components can be removed to facilitate repair, maintenance, upgrades, etc. For example, because the assembled fluid vessel 110 can function as a standalone unit, the fluid vessel 110 can be relatively easily assembled above ground and dropped into a pre-drilled borehole. This may provide the benefit of substantially minimal onsite setup prior to or during installation in the ground. Similarly, if a component of the fluid vessel 110 malfunctions or fails, a module of the fluid vessel 110 containing the failed component can be removed while the remainder of the fluid vessel 110 remains in the ground, which may provide the benefit of reduced maintenance costs and improved longevity of the system 100 over time. Furthermore, because the interface cap 112 is openable and/or removable, maintenance of the fluid vessel 110 can be simplified, particularly since other components of the fluid vessel 110 can be service without removal from the ground. In particular, removal of the entire fluid vessel 110 from a borehole in which the fluid vessel 110 is installed may necessitate re-drilling of the borehole, which may substantially increase the cost of ownership and maintenance of the system 100, and the modularity of the fluid vessel 110 may avoid such drawbacks. However, any other arrangement of the components of the fluid vessel 110 can be used.

[0039] As shown in FIGURES 7 and 8, the system 100 can include more than one fluid vessel 110 (e.g., fluid vessel 110b). The plurality of fluid vessels is preferably configured for arrangement in an array within the ground or a body of water, which may increase the capacity of the system 100 to create a ground-based thermal battery. With such increased heating and/or cooling capability, the system 100 may be particularly applicable for conventional use in residential or commercial buildings. However, the system 100 and method Sioo can be employed in other applications, such as proximal a road surface to prevent ice build-up during winter, in agricultural fields to extend the growing season and/or reduce damage to crops due to temperature fluctuations, with docked ships to provide temperature regulation without continuous operation of a large diesel engine, in a cattle field to warm water troughs for cattle during the winter, or beside a nuclear or solar power plant for storage of waste heat. The plurality of fluid vessels can be arranged substantially close to each other (e.g., 5-ft center-to-center distance) in order to substantially isolate a particular volume of ground for the thermal battery (310 or 320). In particular, concentration of the fluid vessels in a particular volume of ground can result in an increased temperature differential between the particular volume of ground and an adjacent volume of ground and/or the environment (e.g., air above ground). For example, as described in U.S. Patent Application No. 12/742,080, the array of fluid vessels can extract enough heat from the ground during winter to form an "ice ball" in the ground (block S120), and, during summer, heat from the structure is exchanged with the "ice ball" to cool an interior volume of the structure (or other space). Alternatively, the array of fluid vessels can be used to extract heat from a heat-generating source (such as a solar panel, as shown in FIGURE 8, and/or from a power plant) to transfer excess heat into the ground. The thermal energy stored in the ground can subsequently be used to heat a portion of a building (or other device or structure) or to generate electricity when such desired. In a first example, a building or room is heated during winter from thermal energy previously transferred from a nearby power plant into the ground. In a second example, a power plant transfers thermal energy from a turbine, after shutdown, into the ground for storage; subsequently, the power plant transfers the thermal energy back into the turbine upon the next startup. The ground may thus serve as energy storage during low-power demand periods, and energy stored in the ground can be extracted during higher demand periods. However, any other suitable arrangement and/or function for the plurality of fluid vessels can be used.

[0040] In the variation in which a plurality of fluid vessels no (or thermosiphon vessels 400 are incorporated into a thermosiphon array, the interface cap 112 of each a fluid vessel 110 preferably incorporates at least one valve to isolate the fluid vessel 110 from the rest of the fluid vessels and/or the fluid routing system 130. The valves are preferably manual ball valves, with one manual ball valve at each of the return line 135 the supply line 134, and/or the vapor supply line 134b. However, the valves can be of any other valve type and can be electrically-, hydraulically-, pneumatically-, or otherwise operated. The valves can also be arranged elsewhere on the fluid vessel 110 or in the fluid routing system 130. These valves preferably function to isolate the fluid vessel 110 (or thermosiphon vessel 400) from the fluid vessels (or thermosiphon vessels) for maintentance purposes. Specifically, the valves can be operated to depressurize a particular fluid vessel 110 without depressurizing the entire array (210 or 220). Portions of the thermosiphon array (210 or 220) can therefore continue to operate while a portion of the array is undergoing maintenance.

3. Wicking Feature and Directing Geometry:

[0041] As shown in FIGURE 10, the system 100 and the thermosiphon vessel 400 can include a wicking feature 116 arranged within the fluid vessel 110 and configured to retain liquid-state working fluid substantially adjacent an inner wall of the heat exchange tube 114, as shown in FIGURE 10. The wicking feature 116 is preferably a wicking material that is a porous composition applied to the inner surface of the heat exchange tube 114, wherein the porous composition draws working fluid toward the heat exchange tube 114. In this variation, the porous material can be adhered to, sprayed onto, pushed against, or otherwise applied to the inside wall of the heat exchange tube 114 by any suitable method. The porous material can be a Thinsulate material by 3M, though the porous material can be any other suitable material. Alternatively, the wicking feature can be a wicking material that is a textile, such as a polyester cloth arranged within the fluid vessel. The textile is preferably retained against the inner wall of the heat exchange tube 114. For example, the textile can be in the form of a sleeve interposed between the heat exchange tube 114 and a coil spring, wherein the coil spring is configured to press the textile against the inner wall of the tube 114. In another alternative, the wicking feature is a plurality of channels of substantially minimal cross section arranged along the an inner surface of the heat exchange tube 114. The wicking feature 116 can similarly be a plurality of ridges along the inner surface of the heat exchange tube 114. The wicking feature 116 can thus operate by whetting in the presence of the working fluid, via capillary action, via a chemical reaction, or by any other action.

[0042] In another variation, the wicking feature 116 is arranged within the wall of the heat exchange tube 114. The heat exchange tube 114 can include a hollow wall, wherein the void within the wall is substantially filled with the wicking material. The inner surface of the hollow wall of the tube 114 can also be perforated such that the wicking material draws working fluid through the perforations in the inner surface and toward the outer surface of the hollow wall. The wicking feature can thus serve to pull (liquid-state) working fluid toward the outer wall of the heat exchange tube 114 and retain the working fluid in such position over an extended period of time to improve the volume of heat transfer between the working fluid and the ground. However, the wicking feature 116 can be of any form, of any other material, and arranged within the heat exchange tube 114 in any other way. The wicking feature 116 may also extend into any portion of the fluid routing system.

[0043] The heat exchange tube 114 can additionally or alternatively include a directing geometry 115, as shown in FIGURES 11A-11C, that functions to increase the surface area of the inner surface of the heat exchange tube 114. The directing geometry 115 can thus increase the rate of heat transfer between working fluid and the ground, such as by increasing the time that liquid-state working fluid is in contact with the wall of the heat exchange tube 114, which can increase the efficiency of the thermosiphon vessel 400 and the system 100 as a whole.

[0044] In one variation, the directing geometry 115 can define a spiral geometry on the inner surface of the heat exchange tube 114. In this variation, working fluid preferably travels down the heat exchange tube 114 along the spiral geometry, which lengthens the travel time as the liquid-state working fluid passes downward from proximal the top of the tube 114. In this variation, passage blocks can be arranged intermittently along the length of the spiral to retain various volumes of working fluid within the spiral for even great amounts of time, wherein, as a volume of working fluid retained by a passage block increases, working fluid can overflow into a subsequent section of the spiral path and on to the next passage block.

[0045] In another variation of the directing geometry, shown in FIGURES 11B and 11C, the directing geometry 115 can include a series of fluid capturing features arranged along the inner surface of the heat exchange tube 114. Each fluid capturing feature can capture working fluid as working fluid flows down and along the inside wall of the heat exchange tube 114 due to the force of gravity. As shown in FIGURES 11B and 11C, a plurality of fluid capturing features can be arranged substantially proximal each other along the length of the inner surface of the heat exchange tube 114 to create a cascading effect as working passes down the fluid vessel 110. In this variation, the fluid capturing features can be mesh or plastic extruded tabs extending from the inner wall of the heat exchange tube 114 toward the center thereof, wherein the tabs slow working fluid as drops of working fluid from one tab to the next below. The tabs preferably define a plurality of opens of an appropriate size to slow but not completely restrict flow of working fluid through the fluid capturing features. The tabs could also form complete circular rings around the tube, each in sequence. In the variation in which working fluid is water, the tabs can be a 2mm mesh defining nine opens per square centimeter of mesh. However, the tabs can be of any other size and define any other number of opens.

[0046] The directing geometry 115 can be formed, cut, molded, pressed, stamped, extruded, or otherwise incorporated directly into the heat exchange tube 114. Alternatively, the directing geometry 115 can be distinct from and installed into the heat exchange tube 114. For example, the directing geometry 115 that is a spiral path can be formed of a length of sheetmetal bent into a spiral with fluid capturing features, such as the "V" geometry shown in FIGURE 11C, and the sheetmetal spiral can then be inserted into the heat exchange tube 114. In this example, the spring property of the sheetmetal can retain the directing geometry 115 substantially against the inner surface of the heat exchange tube 114. In this example, passage blocks can also be physically coextensive with the sheetmetal spiral, such as by folding a portion of the sheetmetal substantially perpendicular to the spiral path to define a passage block. In another example, a stamping process gather material at particular intervals along the heat exchange tube 114 (or along the directing geometry 115 that is distinct from the tube 114) to define the directing geometry 115 and form fluid capturing features. The spiral path is preferably configured to be substantially non-permanently assembled in the fluid vessel 110, which may permit subsequent removal and/or replacement of the directing geometry 115 when the fluid vessel 110 is installed in the ground. However, any other manufacturing process can be used to form the directing geometry 115.

[0047] The directing geometry 115 can also be physically coextensive with the wicking material or can include separate wicking material arranged thereon to increase the rate of heat transfer between the directing geometry 115 and the working fluid. The wicking material is preferably adhered to or sprayed onto the directing geometry 115 prior to assembly within the heat exchange tube 114. The directing geometry 115 can also be mechanically fastened joined, fixed, bonded, grafted, or otherwise coupled to the heat exchange tube 114 to add structural rigidity and/or flexibility to the fluid vessel 110.

[0048] In the variation in which the fluid vessel 110 is arranged within the ground, the wicking material 114 and/or the directing geometry 115 is/are preferably arranged within the heat exchange tube 114 at a height that does not substantially affect the temperature of the ground in which plant roots and other habitats within the soil are located. For example, the directing geometry 115 is preferably arranged no higher in the fluid vessel 110 than i2-2oft (3.7-6111) below grade when the fluid vessel 110 is installed in the ground, as shown in FIGURE 1.

4, Heat Exchange System

[0049] The heat exchange system 120 of the preferred embodiment functions to communicate thermal energy between working fluid transfers and any of the environment, the structure, the building, the device, etc. In a first variation, the heat exchange system 120 includes a single heat exchanger, which can be arranged within, proximal, or external the structure. In one example, the single heat exchanger is arranged within a room of the structure that is a residential building. At night and/or throughout a portion of winter, the heat exchanger releases thermal energy into the house to both warm the house and to cool the ground. In another example, the single heat exchanger is arranged above an agricultural field, and during the day and throughout a portion of summer, the heat exchanger absorbs thermal energy from the environment into working fluid to heat the ground beneath the agricultural field, which may improve crop yield as the crops experience less drastic temperature swings throughout a 24-hour period, such as in the fall. In this example, the system 100 can be applied to a vineyard, wherein the temperature of the field is kept substantially warm at night to resist frost and freezing of the grapes.

[0050] In a second variation, the heat exchange system 120 includes a plurality of heat exchangers, as shown in FIGURE 1, including an indoor heat exchanger 121 and an outdoor heat exchanger 122. In this variation, the indoor heat exchanger 121 is preferably configured to communicate thermal energy between working fluid, the ground, and the interior volume of the structure, and the outdoor heat exchanger 122 is preferably configured to communicate thermal energy between working fluid, the ground, and the environment (i.e. air, water, etc. external the structure).

[0051] The heat exchangers can be any suitable type of heat exchanger, such as a shell and tube heat exchanger, a heat pump, a solar array, a waste heat source, or any other type of heat exchanger or combination thereof. Furthermore, the heat exchange system can include multiple heat exchangers of various types. The outdoor heat exchanger 122 that is a shell and tube heat exchanger preferably communicates thermal energy between working fluid and ambient air or water from a nearby pond, lake, or other water source. The indoor heat exchanger 121 that is a shell and tube heat exchanger preferably communicates thermal energy between working fluid and air or water from within the structure. As shown in FIGURES 2 and 9, at least one heat exchanger can also include a fan 124 to assist flow of air or other media through the heat exchanger, though any other device can alternatively be used to achieve the same function. At least one heat exchanger can also include or couple to a heat pump 125 configured to communicate thermal energy with another portion of the ground acting as an isothermal heat source, as shown in FIGURE 2. The heat pump 125 is preferably arranged within the structure and is preferably integral with the indoor heat exchanger 121, wherein the function of the heat pump 125 is augmented by the heated or cooled working fluid from the thermosiphon array, which may yield the benefit of increased heat pump efficiency. As shown in FIGURE 9, at least one heat exchanger can also include a secondary condenser 126 and/or evaporator 127.

[0052] The indoor heat exchanger 121 is preferably configured to couple to an HVAC system 100 of a building, as shown in FIGURE 8, such as to cooperate with an air conditioner to cool the building and/or with a heater to heat the building. Alternatively, the indoor heat exchanger 121 can be distinct from a HVAC system of the building, such as a standalone radiator arranged within a room of the building.

[0053] The outdoor heat exchanger 122 is preferably configured for arrangement external the building, as shown in FIGURE 8, such as on a roof or wall of the building or along a fence nearby, wherein air or other media is readily available for sourcing and/or sinking thermal energy. In the variation in which the system 100 us configured to generate a thermal hot battery, the outdoor heat exchanger 122 preferably comprises or is configured to couple to a solar panel (or solar array), wherein the working fluid absorbs thermal energy from the solar panel to heat the working fluid and to cool the solar panel. This may yield the benefit of increasing the efficiency of the solar panel while heating the working fluid well above the ambient air temperature. Specifically, though ambient air temperature may be only 70°F, a solar panel coupled to the outdoor heat exchanger 122 can heat working fluid well over ioo°F during the day due to high energy absorption characteristics of the solar panel. Additionally or alternatively, the outdoor heat exchanger 122 can include or couple to a solar thermosiphon configured to collect thermal energy from the sun, which may yield similar benefits. The outdoor heat exchanger 122 can also be arranged within a power plant and configured to collect excess thermal energy or waste heat for storage in the ground.

[0054] In the variation of the system 100 that includes a first thermosiphon array

210, dedicated to a thermal hot battery 310, and a second thermosiphon array 220, dedicated to a thermal cold battery 320, wherein the thermosiphon arrays use the same type of working fluid (e.g., R-i34a), the thermosiphon arrays can share the same heat exchange system 120 and portions of the fluid routing system 130, as shown in FIGURE 7. However, the first thermosiphon array 210 preferably uses water or a water-based fluid as the working fluid and the second thermosiphon array 220 preferably uses a lower-flash-point fluid, such as R-i34a, and each thermosiphon array is therefore coupled to separate and distinct heat exchange systems 120, 120b, and fluid routing systems 130, 130b.

5, Fluid Routing System

[0055] The fluid routing system 130 of the preferred embodiment functions as a conduit between the fluid vessel 110 and the heat exchange system 120 such that liquid- state working fluid can pass therebetween. The fluid routing system 130 further functions to fluid couple the fluid vessel 110 and the reservoir 180. As shown in FIGURE 1, the fluid routing system preferably includes at least one supply line 134 and a return line 135. In the variation in which the system 100 is configured to create a thermal cold battery 320 by directing vapor-state working fluid to outdoor heat exchanger 122 (block S120), the fluid routing system 130 preferably includes a vapor supply line 134b as well as a liquid supply line 134. In this variation, the pump actively displaces liquid-state working fluid through the liquid supply line 134 toward the indoor heat exchanger 121 to cool the structure (block S140) and vapor-state working fluid passively (i.e. due to gravity) moves from the fluid vessel 110, through the vapor supply line 134b, and into outdoor heat exchanger (block S130). The variation in which the system 100 is configured to create a thermal hot battery 310 can similarly incorporate a vapor supply line 134b to direct vapor-state working fluid toward the indoor heat exchanger 121 to heat the interior volume of the structure. However, in the variation in which the working fluid remains in a single state throughout operation of the system 100 (i.e., the liquid state), the fluid routing system 130 can include only a single supply line 134 and omit the vapor single supply line 134b. However, at least one supply line 134 is preferably fluidly coupled to the pump such that the pump can actively displace (liquid-state) working fluid from the fluid vessel no.

[0056] As shown in FIGURE l, the fluid routing system 130 can comprise one or more valves 133 that function to isolate portions of the heat exchange system 120 from the fluid vessel 110. The one or more valves can also function to moderate transfer of working fluid between the fluid vessel 110 and the reservoir 180. Generally valve 133a can be arranged along the supply line 134 to selectively fluidly couple and decouple the indoor and outdoor heat exchangers 121, 122 to the fluid vessel 110. Valve 133a can be a bi-state valve configured to select one or the other of the heat exchangers 121, 122. However, the valve can be a tri- or quad- state valve and further function to couple and decouple the supply line 134 to the reservoir 180. Valve 133b can be arranged along the return line 135 to selectively fluidly couple and decouple the indoor and outdoor heat exchangers 121, 122 to the fluid vessel 110. Valve 133b can also be a bi-state valve configured to select one or the other of the heat exchangers 121, 122, though valve 133b can be alternatively be a tri- or quad- state valve and further function to couple and decouple the return line 135 to the reservoir 180, though this function can alternatively be performed through valve 133d, as shown in FIGURE 1. In the variation in which vapor-state working fluid is directed from the fluid vessel 110, valve 133c can be arranged along the vapor-state supply 134b to selectively fluidly couple and decouple the indoor and outdoor heat exchangers 121, 122 to the fluid vessel 110. However, any other number of valves can be incorporated into the fluid routing system 130 (or system 100) in any other way. The valves are preferably electrically-actuated solenoid valves and cooperate to direct working fluid through the system 100 to perform the desired function, such as block S110, block S120, block S130, or block S140.

[0057] The fluid routing system 130 preferably comprises at least one enclosed tube communicating fluid between the fluid vessel 110 and the heat exchange system 120. The enclosed tube can be a flexible line, such as a rubber, neoprene, or polyethylene (PE) tube, pipe, or ducting. The enclosed tube can alternatively be a hard line, such as copper, cast iron, polyvinylchloride (PVC), or polypropylene (PP) tube, pipe, or ducting. Portions of the fluid routing system configured to communicate liquid-state working fluid (e.g., the liquid-state supply line 134 and the return line 135) are preferably smaller in inner diameter than portions of the fluid routing system configured to communicate vapor-state working fluid (e.g., the vapor-state supply line 134a). For example, the liquid-state supply line 134 and the return line 135 can be 3/8" (.3751η) inner-diameter tubing, and the state supply line 134a can be 2" (2.0m) inner-diameter tubing.

[0058] Any portion of the fluid routing system can also include wicking material, as described above. However, the fluid routing system 130 can be of any other form, material, geometry, or manufacture and include any other feature or component.

6, Pump

[0059] The pump 150 of the preferred embodiment functions to displace liquid- state working fluid from the fluid vessel 110 to the heat exchange system 120. The pump 150 is operable between two modes, including the energy capture mode and the energy release mode. The pump 150 is preferably ON (i.e. powered) in the energy capture mode to displace liquid-state working fluid out of the fluid vessel 110 and into a portion of the heat exchange system 100. Valves (e.g., 133a, 133d of FIGURE 1) can be manipulated: to siphon working fluid from the supply line 134 to reduce the level of working fluid within the fluid vessel 110; or to reintroduce working fluid, via the return line 135, into the fluid vessel 110 to increase fluid level therein. Specifically, enough liquid-level working fluid is preferably left within the fluid vessel 110 to fully immerse the pump 150, through the level of liquid-state working fluid is also preferably low enough to permit working fluid returning to the fluid vessel 110 to trickle along the inner wall of the heat exchange tube over a large portion of the length thereof.

[0060] The pump 150 can be ON or OFF in the energy release mode. In the variation in which vapor-state working fluid is passively displaced from the fluid vessel 110 to the outdoor heat exchanger 122 in the energy release mode, the pump 150 can be OFF as vapor-state working fluid naturally rises out of the fluid vessel 110 and liquid- state working fluid naturally returns to the fluid vessel. However, in this variation, the pump 150 can be ON and function: to cycle liquid-state working fluid between the reservoir 180 and the fluid vessel 110 to prevent stagnation within the system 100; and/or to maintain the level of liquid-state working fluid within the fluid vessel no below a threshold level by displacing working fluid into the reservoir 180. This variation is preferably suited to the second thermosiphon array 220 configured to generate a thermal cold battery.

[0061] The pump 150 is preferably ON in the variation in which liquid-state working fluid is actively displaced from the fluid vessel 110 to the outdoor heat exchanger 122 in the energy release mode, such as in the first thermosiphon array 210 configured to generate a thermal hot battery. In this variation, the pump 150 can again serve to regulate the liquid-state working fluid level within the fluid vessel 110, in cooperation with at least one valve, as described above. However, the pump 150 can operate in any mode in any other way and the system 100 can include any other number of similar or dissimilar pumps. For example, the system 100 can incorporate a second pump configured to pump working fluid from the reservoir 180 back into the fluid vessel 110, such as through the return line 135.

[0062] The pump 150 is preferably arranged proximal the bottom of the fluid vessel 110 such that the pump "pushes" working fluid out of the fluid vessel 110 rather than pulling working fluid therefrom. This may reduce the possibility of vapor lock immobilizing the system 100. Specifically, the integration cap preferably retains (e.g., houses, is mechanically fastened to) the pump 150. However, the pump 150 can be fastened to the supply line 134 or the heat exchange tube 114, or the pump 150 can be loose within the fluid vessel 110. However, the pump 150 can be arranged in any other way within the system 100.

[0063] The pump 150 is preferably a velocity (e.g., centrifugal) pump powered by an electric motor. However, the pump 150 can alternatively be a positive displacement pump, such as a rotary (e.g., lobe, scroll, screw, or sliding vane) pump, a reciprocating (e.g., piston or diaphragm) pump, or a linear (e.g., rope or chain) pump. The pump 150 can, however, be any other suitable type of pump, such as those described in U.S. Patent Publication No. 2010/0305918, which was filed 07 NOV 2008.

[0064] The pump 150 is preferably an electrically-powered pump configured to receive electricity readily available proximal the structure. The pump 150 preferably accepts single-phase 120VAC power (i.e. power supplied at a standard commercial/residential wall socket). However, the pump 150 can accept single- or three-phase 120VAC, 240VAC, or 480VAC power or 5VDC or 12VDC power, such as supplied through an AD-DC transformer or inverter. However, the pump 150 can accept any other power at any other voltage and/or in any other format. Furthermore, the system 100 can include a transformer, inverter, voltage regulator, or any other requisite element to condition available power into a format suitable for the pump 150. However, the pump 150 can also be powered hydraulically or pneumatically or by any other suitable energy source. j. Reservoir

[0065] The reservoir 180 of the preferred embodiment functions to contain working fluid, such as to retain excess working fluid when the level of liquid-state working fluid within the fluid vessel 110 rises above a (maximum) threshold level and to supply working fluid when the level of working fluid within the fluid vessel 110 drops below a (minimum) threshold level. The reservoir 180 is therefore preferably coupled to the fluid vessel 110 via both the (liquid-state) supply line 134 and the return line 135. The reservoir 180 can also function as an external flow-through vessel, such as when the pump 150 cycles working fluid from the bottom of the fluid vessel 110 to the top of the fluid vessel 110. This may reduce depth-dependent temperature gradient in the ground, reduce potential for system stagnation, and/or increase the volume of heat transfer between the working fluid and the ground.

[0066] The reservoir 180 is preferably configured to be arranged above grade, as shown in FIGURE 2. The reservoir 180 is preferably a tank comprised of material substantially resistant to corrosion in the presence of the working fluid and/or the environment. For example, the reservoir 180 can be a stainless steel or HDPE tank. The reservoir 180 is also preferably configured to hold a volume of working fluid necessary to guarantee efficient operation of the system 100 throughout a period of operation, such as a year, without necessitating addition of more working fluid to the system 100. The reservoir 180 is preferably insulated to maintain the temperature of working fluid pumped from the fluid vessel no, wherein the reservoir 180 holds the heated or cooled working fluid at the ready for future heating and/or cooling needs. However, the reservoir 180 can be of any other suitable form, volume, material, or arrangement.

8, Fluid Level Sensor

[0067] The system 100 can further include a fluid level sensor 160 that functions to monitor the level of liquid-state working fluid within the fluid vessel 110. The fluid level sensor 160 can be a float-type mechanical sensor, wherein an elevated liquid-state working fluid level raises the float, which starts the pump 150 to remove working fluid from the fluid vessel 110. Alternatively, the fluid level sensor 160 can be an optical-based sensor configured to detect the surface of the liquid-state working fluid within the fluid vessel 110, or any other suitable type of fluid level sensor. However, the fluid level sensor 160 can additionally sense the volume or mass of vapor-state working fluid in the fluid vessel 110, though the fluid level sensor 160 can function in any other way.

Q, Processor

[0068] The system 100 can further include a processor 170 that functions to at least a portion of the system. Specifically, the processor 170 is preferably electrically coupled to the pump 150 and the fluid level sensor 160 such that the processor 170 can receive an output of the fluid level sensor 160, test the fluid level in the fluid vessel 110 against a threshold level, and control the state of the pump 150 to suit.

[0069] The processor 170 is also preferably configured to set the state of any valves within the system 110 to control the direction of working fluid through the fluid routing system 130 and heat exchange system 120 based upon desired function. Specifically, the processor 170 preferably adjusts the valves to transition between the energy capture mode (block S110 or S140) and the energy release mode (block S120 or S130). The processor 170 therefore preferably adjusts the valves to transition the system 100 between exchanging thermal energy with the environment (block S120 and S140) and exchanging thermal energy with the structure (blocks S110 and S130). [0070] The processor 170 is preferably wirelessly coupled to the fluid level sensor 160, the pump 150, the valves, and any other electrical component(s) of the system 100. Such wireless communication may ease setup and maintenance of the system 100 since physical wires may not be necessary to connect the processor 170 to the fluid level sensor 160, the pump 150, the valves, etc. However the processor 170 can be wired to any of the components of the system 100, such as through the interface cap 112.

[0071] The processor 170 can also communicate with a remote server to transmit and/or receive relevant system data thereto and/or therefrom. The processor 170 can also receive firmware updates from the remote server, such as updated control algorithms for transitions between the energy release and capture modes. Also or alternatively, the processor 170 can communicate with a data storage module to store and access data pertaining to past and current operation of the system 100, wherein such data can also be used by the processor to generate trend lines or expectations of future system operations, such as an expected volume of heat transfer given certain environment condition (e.g., ambient temperature or cloud cover) or an ideal time for mode transition during a particular day in a particular season. The processor 170 can further communicate with any other sensor within the system 100, such as a barometer or an air temperature sensor. The processor 170 can also capture data from a series of temperature sensors 161 arranged within the thermosiphon and/or within the ground at various depths below grade and/or at various distances from the fluid vessel 110, as shown in FIGURE 2. The processor can use such temperature data to generate a thermal map of the ground-based hot and/or cold battery. However, the processor 170 can perform any other function, manipulate relevant data in any other way, and/or control any other component or sensor(s) of the system 100.

10. The Display

[0072] The system 100 can also include a display 190 that functions to present information regarding operation of the system 100 to a user, as shown in FIGURE 2. The display 190 is preferably a digital display (e.g., LED, OLED, LCD, e-ink, segment display) electrically coupled to and receives relevant system data from the processor 170. However, the display 190 can alternatively be in direct communication with any component of the system 100 or sensor proximal thereto. The display 190 can also be in communication with a remote server that provides past data of the system 100 or data pertaining to other similar systems. The display 190 is preferably a digital display that informs a user if the system 100 is operating correctly, if a particular component is performing abnormally, and/or if a failure is expected. The display 190 can also present such information as the temperature of the ground at a certain depth and/or distance from the fluid vessel 110, the temperature inside the fluid vessel 110, the level of fluid within the system 100, the fluid vessel 110, and/or reservoir 180, the pressure within the fluid vessel 110, the flow rate of working fluid through a portion of the fluid routing system 130, power consumption of the pump 150, and/or any other suitable information. Alternatively, the display 190 can comprise idiot lights. For example, the display 190 can be a pair of LEDs, wherein a first LED of a first color (e.g., green) is powered ON when all operation parameters are within acceptable ranges for the system 100, and wherein a second LED of a second color (e.g., red) is ON powered when attention is needed. However, any other suitable method to display information can be used. The display 190 can alternatively comprise a smartphone of a user, wherein system data is transmitted wireless, such as via Wi-Fi, Bluetooth, or a cellular connection, to the smartphone. The display 190 can be arranged above grade and in a location substantially convenient for the user, such as proximal an air conditioner, a furnace, a thermostat, an alarm panel, or a fuse box. However, the display 190 can be configured for arrangement in any other location.

[0073] As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes may be made to the preferred embodiments of the invention without departing from the scope of the invention as defined in the following claims.

Claims

CLAIMS We Claim:

1. A system for storing seasonal environment energy for temperature regulation of a structure, the system comprising:

• a fluid vessel including a heat exchange tube and a bottom, configured to be installed in the ground, and to contain working fluid;

• a reservoir coupled to the fluid vessel and configured to store working fluid;

• a heat exchange system comprising:

o an indoor heat exchanger configured to communicate thermal energy between working fluid and an interior volume of the structure; and

o an outdoor heat exchanger configured to communicate thermal energy between working fluid and the environment;

• a pump configured to displace fluid from the fluid vessel to the reservoir to maintain the level of liquid-state working fluid below a threshold level within the fluid vessel, the pump operable between:

o an energy capture mode, wherein the pump displaces liquid-state working fluid from the fluid vessel to a portion of the heat exchange system, wherein the heat exchange system communicates thermal energy into the working fluid and the fluid vessel communicates the thermal energy into the ground for storage; and

o an energy release mode, wherein working fluid is displaced from the fluid vessel to a portion of the heat exchange system, wherein the fluid vessel communicates thermal energy stored in the ground into the working fluid and the heat exchange system communicates the thermal energy out of the working fluid.

2. The system of Claim l, further comprising a second fluid vessel configured to be installed in the ground proximal the fluid vessel and further comprising a second pump configured to displace fluid from the second fluid vessel to the reservoir to maintain the level of liquid-state working fluid within the fluid vessel, the second pump operable between:

• an energy capture mode, wherein the second pump displaces liquid-state working fluid from the second fluid vessel to a portion of the heat exchange system, wherein the heat exchange system communicates thermal energy into the working fluid and the second fluid vessel communicates the thermal energy into the ground for storage; and

• an energy release mode, wherein working fluid is displaced from the second fluid vessel to a portion of the heat exchange system, wherein the second fluid vessel communicates thermal energy stored in the ground into the working fluid and the heat exchange system communicates the thermal energy out of the working fluid.

3. The system of Claim 1, wherein an inner surface of the heat exchange tube defines a directing geometry along a portion of the length thereof.

4. The system of Claim 1, further comprising a wicking feature arranged within the fluid vessel and configured to retain liquid-state working fluid substantially adjacent an inner wall of the heat exchange tube.

5. The system of Claim 4, wherein the wicking feature is arranged along the inner surface of the heat exchange tube and is selected from the group consisting of: a porous material; a textile; a plurality of channels of substantially minimal cross section; and a plurality of ridges.

6. The system of Claim 1, wherein the reservoir is configured to store excess fluid and to be arranged above ground, wherein the pump is further configured to cycle liquid- state working fluid between the fluid vessel and the reservoir while maintaining the level of liquid-state working fluid below the threshold level.

7. The system of Claim 1, further comprising a fluid level sensor arranged within the fluid vessel and configured to determine the level of liquid-state working fluid within the fluid vessel.

8. The system of Claim 7, further comprising a processor configured to control the pump based upon an output of the fluid level sensor.

9. The system of Claim 1 configured to function as a heating system, wherein, in the energy capture mode, the pump displaces liquid-state working fluid toward the outdoor heat exchanger to capture thermal energy from the environment and the fluid vessel communicates the thermal energy into the ground to generate a soil- based thermal hot battery proximal the fluid vessel, and wherein, in the energy release mode, the fluid vessel communicates thermal energy from the soil-based thermal hot battery into the working fluid and the indoor heat exchanger communicates the thermal energy from the working fluid to the interior volume of the structure.

10. The system of Claim 9, wherein the fluid vessel and the reservoir are configured to contain working fluid that comprises water.

11. The system of Claim 1 configured to function as a cooling system, wherein, in the energy release mode, the fluid vessel communicates thermal energy from the ground into the working fluid and the outdoor heat exchanger communicates the thermal energy from the working fluid to the environment to generate a soil-based thermal cold battery proximal the fluid vessel, and wherein, in the energy capture mode, the pump displaces liquid-state working fluid toward the indoor heat exchanger to capture thermal energy from the interior volume of the structure and the fluid vessel communicates the thermal energy into the ground.

12. The system of Claim n, wherein the fluid vessel and reservoir are configured to contain working fluid that is R-i34a refrigerant.

13. The system of Claim 1, wherein the pump is configured to operate in the energy capture mode substantially during a period of substantially high environmental temperatures and to operate in the energy release mode during a period of substantially low environmental temperatures.

14. The system of Claim 1, wherein the indoor and outdoor heat exchangers are physically distinct, the indoor heat exchanger is configured to be arranged within the structure, and the outdoor heat exchanger is configured to be arranged external the structure.

15. The system of Claim 14, wherein the indoor heat exchanger comprises a heat pump.

16. The system of Claim 14, wherein the outdoor heat exchanger comprises a solar array.

17. The system of Claim 1, wherein the heat exchange system comprises a shell and tube heat exchanger and a fan configured to blow air therethrough.

18. The system of Claim 1, further comprising an external display configured to display, to a user, information regarding operation of at least one of the fluid vessel, the heat exchange system, the reservoir, and the pump.

19. The system of Claim 1, further comprising a valve configured to selectively isolate the indoor and outdoor heat exchangers from the fluid vessel.

20. A method for regulating the temperature within a structure with a first thermosiphon array of fluid vessels, installed in the ground proximal the structure, and a second thermosiphon array of fluid vessels, installed in the ground proximal the structure and substantially removed from the first thermosiphon array, the method comprising:

during a period of substantially high environmental temperatures:

o generating a thermal hot battery of the ground proximal the first thermosiphon array by directing liquid-state working fluid from the first array of fluid vessels through an outdoor heat exchanger exposed to the environment, wherein working fluid absorbs thermal energy from the environment and releases the thermal energy into the ground, proximal the first thermosiphon array, for storage; and

o cooling the structure by directing liquid-state working fluid from the second array of fluid vessels through an indoor heat exchanger coupled to the structure, wherein working fluid absorbs thermal energy from the structure and releases the thermal energy into the ground proximal the second thermosiphon array; and

during a period of substantially low environmental temperatures:

o generating a thermal cold battery of the ground proximal the second thermosiphon array by directing vapor-state working fluid from the second array of fluid vessels through an outdoor heat exchanger exposed to the environment, wherein working fluid absorbs thermal energy from the ground proximal the second thermosiphon array and releases the thermal energy to the environment; and

o heating the structure by directing working fluid from the first array of fluid vessels through an indoor heat exchanger coupled to the structure, wherein working fluid absorbs thermal energy from the ground proximal the first thermosiphon array and releases the thermal energy into the structure.

The method of Claim 20, wherein generating the thermal cold battery of the ground comprises passively pumping vapor-state working fluid out of the second array of fluid vessels.

22. The method of Claim 20, wherein generating the thermal hot battery of the ground and cooling the structure comprise actively pumping liquid-state working fluid out of the first array of fluid vessels.

23. The method of Claim 20, further comprising maintaining the level of liquid-state working fluid within each fluid vessel of the first and second thermosiphon arrays below a threshold level.

24. A thermosiphon vessel for storing seasonal environment energy in the ground, the thermosiphon comprising:

• a fluid vessel comprising a heat exchange tube, configured to contain a working fluid, and further configured to receive a fluid inlet and a fluid outlet;

• a wicking feature arranged within the fluid vessel and configured to retain liquid- state working fluid substantially adjacent an inner wall of the heat exchange tube;

• a fluid level sensor arranged within the fluid vessel and configured to determine the level of liquid-state working fluid therein; and

• a pump arranged within the fluid vessel, configured to maintain the level of liquid- state working fluid below a threshold level within the fluid vessel, and operable between:

o an energy capture mode, wherein the pump displaces liquid-state working fluid from the fluid vessel to absorb thermal energy from an above-ground heat source, wherein the fluid vessel communicates the thermal energy from the working fluid into the ground for storage; and

o an energy release mode, wherein working fluid is directed from the fluid vessel to release thermal energy to an above-ground heat sink, wherein the fluid vessel communicates thermal energy stored in the ground into the working fluid.

25. The method of Claim 24, wherein the wicking feature is configured to direct working fluid toward an inner wall of the heat exchange tube by capillary action.

26. The method of Claim 24, wherein the wicking feature is a textile material retained against the portion of the inner wall of the heat exchange tube by a coil spring.

27. The method of Claim 24, further comprising a directing geometry arranged along a portion of an inner wall of the heat exchange tube.

28. The method of Claim 27, wherein the directing geometry comprises one or more features selected from the group consisting of: a ridge, a cup, a prong, a shelf, and a perforated sheet.

29. The system of Claim 24, wherein the fluid vessel further comprises an interface cap transiently coupled to the top of the heat exchange and configured to receive the fluid inlet and the fluid outlet.

30. The system of Claim 29, wherein the fluid vessel further comprises an integration cap coupled to the bottom of the heat exchange tube, opposite the interface cap, and configured to retain the pump.