LOOP THERMAL ENERGY SYSTEM

FIELD

The subject matter disclosed herein relates to energy production from low-temperature heat sources.

BACKGROUND
Description of the Related Art

Low-temperature heat sources including ground-source geothermal and waste heat sources such as from building refrigeration systems are plentiful. However, because of the low-temperatures of these sources, it has been difficult to recover useable mechanical energy.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the embodiments of the invention will be readily understood, a more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of a thermal loop;

FIG. 2 is a schematic block diagram illustrating one embodiment of a thermal loop with storage tanks;

FIG. 3 is a schematic block diagram illustrating one embodiment of a thermal loop with heat exchangers;

FIG. 4 is a schematic block diagram illustrating one embodiment of a thermal loop with coaxial heating and cooling;

FIG. 5 is a schematic flow chart diagram illustrating one embodiment of thermal loop method; and

FIG. 6 is a schematic block diagram illustrating one embodiment alternate of a thermal loop.

DETAILED DESCRIPTION

The schematic flowchart diagrams and/or schematic block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the schematic flowchart diagrams and/or schematic block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions of the program code for implementing the specified logical function(s).

It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures.

Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer readable program code.

Embodiments of the present invention utilize water-to-water heat pumps to produce hot water that heats a first fluid. The heated first fluid is used to motivate an engine, producing useful mechanical motion.

FIG. 1 is a schematic block diagram illustrating one embodiment of a thermal loop 100. The thermal loop 100 includes an engine 105, a heat source 110, a heat pump 115, and pressure tanks 120. Although for simplicity two pressure tanks 120 are depicted, two or more pressure tanks 120 may be employed. In a certain embodiment, the thermal loop 100 includes a pressure pump 125, a cold source 130, tank valves 165, a charging valve 160, and a discharging valve 145.

The heat source 110 may be ground-source geothermal heat, waste heat from a building's refrigeration system, or the like. The heat source 110 may have temperature in the range of a 12° C. to 45° C. In a certain embodiment, the heat source 110 has a temperature in the range of 12° C. to 100° C. The heat source 110 may supply a warm fluid to the heat pump 115 through a heat source feed 190. The heat source feed 190 may be a closed loop circulating water, a refrigerant, or the like. Alternatively, the heat source feed 190 may be an open loop supply of warm water.

The heat pump 115 may heat a first fluid to a first temperature using heat from the heat source 110. In one embodiment, the first temperature is in the range of 50° C. to 75° C. Alternatively, the first temperature is in the range of 50° C. to 125° C.

In a certain embodiment, the first fluid has a bubble point in the range of 45° C. to 60° C. Alternatively, the first fluid may have a bubble point in the range of 40° C. to 70° C. The first fluid may be an organic, high molecular mass fluid. In one embodiment, the first fluid is selected from the group consisting of propane, propene and propylene.

In the depicted embodiment, the heat pump 115 heats the first fluid by heating a second fluid that is carried through a heat pump feed 170 and a pressure tank value 165 to a tank feed 175. The second fluid may be water. Alternatively, the second fluid may be an organic fluid. The tank feed 175 may comprise tubing in physical communication with a pressure tank 120. Alternatively, the tank feed 175 may comprise tubing within a pressure tank 120.

In one embodiment, the cold source 130 supplies a cold fluid through a cold source feed 185. The cold fluid may be directed by a tank value 165 to a tank feed 175.

The second pressure tank 120b may discharge the heated first fluid through the discharging valve 145 and a first fluid feed 140 to the engine 105. In one embodiment, the engine 105 is a tesla turbine. Alternatively, the engine 105 is a stirling engine. The first fluid is exhausted from the engine 105 through an exhaust feed 150.

In one embodiment, a pressure pump 125 increases the pressure of the first fluid and supplies the pressurized first fluid through a first fluid source 155 to the charging valve 160. The charging valve 160 may charge the first pressure tank 120a with the first fluid while the second pressure tank 102b is discharging the first fluid through the discharging valve 145. When the first pressure tank 120a is fully charged, the charging valve 160 may charge the second pressure tank 120b with the first fluid while the first pressure tank 120a discharges the first fluid through the discharging valve 145.

In one embodiment, the charging value 160 only charges one of the pressure tanks 120 while blocking first fluid from entering the other pressure tank 120. In addition, the discharging value 145 may only discharge the first fluid from one of the pressure tanks 120 while blocking the first fluid from discharging from the other pressure tank 120.

In one embodiment, a first pressure tank 120a is charged with the first fluid from the charging valve 160 and the first fluid in the first pressure tank 120a is cooled and/or condensed by directing the cold fluid through a first tank value 165a to a first tank feed 175a. The first fluid may then be heated by directing the second fluid through the first tank valve 165a to the first tank feed 175a.

FIG. 2 is a schematic block diagram illustrating one embodiment of a thermal loop 200 with storage tanks 205. The thermal loop 200 may be the thermal loop 100 of FIG. 1 with added storage tanks 205. The description of the thermal loop 200 refers to elements of FIG. 1, like numbers referring to like elements. Although for simplicity two storage tanks 205 and two pressure tanks 120 are shown, any number of storage tanks 205 and two or more pressure tanks may be employed.

The first fluid of the exhaust feed 150 may be directed through an exhaust value 215 to one of a first storage tank 205a and a second storage tank 205b. In one embodiment, cold fluid from the cold feed 185 cools and condenses the first fluid in the storage tanks 205. In one embodiment, the exhaust valve 215 may direct the first fluid to the first storage tank 205a and block the first fluid from entering the second storage tank 205b while a storage valve 210 directs the first fluid from the second storage tank 205a to the pressure pump 125 and/or first fluid source 155. In a certain embodiment, the first fluid flows from the storage value 210 directly to the charging valve 160 without passing through the pressure pump 125.

In the depicted embodiment, the heat pump 115 supplies heated first fluid to the pressure tanks 120 through the tank feeds 175. The charging value 160 charges the first pressure tank 120a with the cooled first fluid while the discharging valve 145 discharges the second pressure tank 120b. The charging valve 160 may then charge the second pressure tank 120b with the cooled first fluid while the discharging valve discharges the first pressure tank 120a.

FIG. 3 is a schematic block diagram illustrating one embodiment of a thermal loop 300 with heat exchangers 305. The thermal loop may be the thermal loop 200 of FIG. 2 with the addition of heat exchangers 305. The description of the thermal loop 300 refers to elements of FIGS. 1-2, like numbers referring to like elements. Although for simplicity two storage tanks 205 and two pressure tanks 120 are shown, any number of storage tanks 205 and two or more pressure tanks may be employed.

The heat pump 115 may supply cold through a cold feed 345 to a cold tank 310. The heat pump 115 may also supply heat to a hot tank 315 through a hot feed 350. The heat pump 115 may use a closed loop to supply the cold and the heat as is well known to those of skill in the art.

The cold tank 310 may store cooled water, a cooled fluid, or the like. For simplicity, the embodiment using cooled water is described. The cold tank 310 may supply the cooled water to a first heat exchanger 305a to cool and/or condense the first fluid from the storage valve 210. The hot tank 315 may store hot water, a heated fluid, or the like. For simplicity, the embodiment using hot water is described. The hot tank 315 may supply the hot water to a second heat exchanger 305b to heat the first fluid. The second heat exchanger 305b then supplies the heated first fluid through the first fluid source 155 and the charging valve 160 to the pressure tanks 120. The charging value 160 alternates between charging the first pressure tank 120a and the second pressure tank 120b with the heated first fluid.

The depicted embodiment shows three pressure pumps 125 that increase the pressure of the first fluid. Embodiments may be practiced with and/or without any of the depicted pressure pumps 125.

FIG. 4 is a schematic block diagram illustrating one embodiment of thermal loop 400 with coaxial heating and cooling. The thermal loop 400 is the thermal loop 100 of FIG. 1 with coaxial pipes 405, 410. The description of the thermal loop 400 refers to elements of FIGS. 1-3, like numbers referring to like elements. A cold coaxial pipe 405 and a hot coaxial pipe 410 are shown.

The cold coaxial pipe 405 includes an inner pipe carrying the first fluid within an outer pipe carrying the cold fluid from the cold source feed 185. The cold coaxial pipe 405 further cools and/or condenses the first fluid exhausted from the engine 105 in the exhaust feed 150.

The hot coaxial pipe 410 includes an inner pipe carrying the heated first fluid within an outer pipe carrying the second fluid from the heat pump feed 170. The hot coaxial pipe 410 further heats the heated first fluid of the first fluid feed 140.

FIG. 5 is a schematic flow chart diagram illustrating one embodiment of thermal loop method 500. The method 500 performs the functions of the apparatus in FIGS. 1-4. The description of the method 500 refers to elements of FIGS. 1-4, like numbers referring to like elements.

The heat pump 115 heats 505 a first fluid to the first temperature using heat from the heat source 110. The heated first fluid charges 510 the first pressure tank 120a with the heated fluid. Concurrently, the second pressure tank 120b discharges the heated fluid stored in the second pressure tank 120b during a previous charging. The discharged heated first fluid motivates the engine 105.

The discharged heated first fluid may be a gas. For example, the headed fluid stored in the second pressure tank 120b may transition from a liquid to a gas. Alternatively, the discharged heated first fluid may be a liquid. In one embodiment, the engine 105 delivers torque to a generator (not shown) that generates electricity as is well known to those of skill in the art.

The charging valve 160 and discharging value 145 may further reverse 525 the charging and discharging pressure tanks 120. For example, the charging valve 160 may charge the second pressure tank 120b and the discharging valve 145 may discharge the heated first fluid from the first pressure tank 120a.

FIG. 6 is a schematic block diagram illustrating one embodiment of an alternate thermal loop 600. The thermal loop 600 may be one embodiment of the thermal loop 300 of FIG. 3. The description of the thermal loop 600 refers to elements of FIGS. 1-4, like numbers referring to like elements.

The thermal loop 600 is a hybrid system which utilizes fluid to fluid heat pumps to produce hot and cold water that is stored in separate pressure tanks 17, 20. The pressure tanks 17, 20 may be the pressure tanks 120 of FIGS. 1-4. A fluid-filled, closed ground loop is alternately used as both a heat source and a heat sink. Other systems may also serve as heat sources and heat sinks. First fluid in the pressure tanks 120 is used for production of domestic hot water, space heating and cooling, as well as for providing for separation of temperature zones within a first fluid closed loop. The first fluid is preferably an organic compound, such as propane, propene or propylene, all of which have a boiling point much lower than that of water. The first fluid is used to provide working energy for the turbine 23 or a positive displacement motor, which is, in turn, coupled to an electrical generator 24. Power provided by the electrical generator 24 can be used for a residence or other buildings. Unused electrical capacity can be sold back to an electrical utility company through net metering programs. Batteries 34 may be used to store electricity, and the generator 24 may be used to start and/or assist the thermal loop 600. One purpose of the thermal loop 600 is to provide for a portion of an occupied structure's utility needs at least partially independent of the electrical grid. An embodiment will now be described with reference to FIG. 6. It should be further noted that in the present embodiment, domestic culinary water flows through the paths represented by items 7A and 9A in the drawing, although other fluids may also be appropriate. These flows are isolated from the fluids in the tanks 7 and 9.

Referring now to the FIG. 6, a first water-to-water single or two-stage reverse cycle heat pump 1 is used to prioritize water heating by moving heat from a fluid stored in a cold tank 9 or moving heat from a heat source such as a ground loop 11 by circulating a fluid contained in a buried closed polyethylene or any thermal transfer pipe loop through the heat exchanger of the heat pump 1, compressing it, and then circulating this heat through the hot tank 7 in a closed loop. The result of extracting heat out of a cold tank 9 and moving this heat to a hot tank 7, is maintaining a desired cool tank and hot tank temperature. When a desired temperature is satisfied as determined by the programmable logic controller (PLC) 36 in the cold tank 9 and/or hot tank 7 and heat is still being demanded, excess cold can be rejected or moved to the ground in a heating dominant situation. The flow path of the second fluid can be determined by the PLC 36 according to a desired demand preference. It should be understood that the first heat pump 1 and the second heat pump 4 each includes a compressor, a closed loop containing a refrigerant liquid such as R410A, and a heat exchanger unit. The heat exchanger of the first heat pump 1 transfers heat from either the cold tank 9 or from the ground loop 44 to the hot tank 7. The heat exchanger of the second heat pump 4 transfers heat from the cold tank 9 to either the hot tank 7 or the ground loop 44.

A first set of circulating pumps 2, having internal check valves, force a determined volume of second fluid in a desired path, extracting heat and rejecting cold through the heat pump 1. A first set of three-way valves 3 allow the rejected hot/cold second fluid to be routed to the hot/cold storage tanks 7, 9 or to the earth as determined by a temperature requirement from the system PLC control 36.

A second water-to-water single or two-stage reverse cycle heat pump 4 is used to prioritize water cooling by moving heat from fluid stored in the cold tank 9 to a heat pump 4, compressing this heat, then moving it through a heat exchanger to the hot storage tank 7 or moving this heat to a heat sink (not shown). Through the process of compressing heat circulating from the cold tank 9 and moving this heat to the hot tank 7 or to the ground, cooling of the cold storage tank 9 continues. When a desired temperature is satisfied as determined by the PLC 36 in the cold tank 7 and/or the pressure tanks 17, 20 and no heat is desired by the hot tank 7 or pressure tank 17, 20, then this excess heat can be rejected to the ground in a cooling dominant situation. The flow path of the second fluid can be determined by the PLC 36 according to a desired demand preference.

A second set of circulating pumps 5 having internal check valves force a determined volume of fluid in a desired path, extracting heat and rejecting cold through the heat pumps 1, 4. A second set of three-way valves 6 allow the rejected hot and cold fluid to be routed to the hot tank 7 and cold tank 9 respectively and/or to the earth as determined by a temperature requirement from the system PLC control 36.

A hot tank 7 stores a thermal mass of second fluid (preferably water) and serves as a buffer to maintain the flashing of a low boiling point first fluid to a vapor circulating in another closed loop through a heat exchanger 16, and also provide space forced air or radiant floor heating and the heating of domestic water.

Potable water can pass through an independent coil resting in the hot tank 7 for the purpose of providing domestic heating water 7A. Second fluid can be circulated from the hot tank 7 to a first fan coil unit 7B for the purpose of space heating or to a radiant floor or under slab loop for radiant heating. A first single circulating pump 8 having an internal check valve forces the flow of hot fluid through a heat exchanger 16 to provide heat for flashing the independent first fluid loop to a vapor or gas.

The cold tank 9 stores a cold mass of fluid (preferably water), and serves as a buffer to maintain the condensing of the first fluid vapor to a fluid in a closed loop through a heat exchanger and also provide other functions such as space cooling, refrigeration keeping food cool, cooling potable water, or any other cooling need.

Water can pass through a second independent tank coil to provide cold water 9A which can be used for several functions such as food refrigeration, cooling potable water, or any other cooling need. Fluid can be circulated from the cold tank to a second fan coil unit 9B for the purpose of space cooling.

A second single circulating pump 10 having an internal check valve forces the flow of cold fluid through a heat exchanger 15 to provide chilling for condensing the first fluid vapor in the closed loop to a liquid. A flow path 11 to a buried closed loop of polyethylene pipe or any thermal transfer pipe loop encased in the earth serves the purpose of exchanging heat or cold to and from the earth to the hot tank 7 and cold tank 9 as required by the PLC 36 according to a demand preference.

Desuperheater loops 12 can be routed to each tank 7,9 as needed to utilize excess compressor heat. For example if the cold tank 9 approaches freezing one desuperheater 12 could send excess heat to the cold tank 9 to prevent freezing. In another scenario excess heat could be sent to the hot tank 7 to assist in heating. These functions can be determined and controlled by the PLC 36.

A variable speed circulating pump 13 forces the first fluid in its condensed state through the closed loop circuit at a rate that creates the most pressure when the fluid flashes to a vapor. This volume can be determined by the PLC 36 to optimize pressure in the closed first fluid loop.

A pressure reducing valve (PRV) 14 having a pressure gage lowers the pressure of the first fluid to an optimum pressure before the fluid is forced through the closed loop by the variable speed pump 13. A first plate heat exchanger 15 installed in the path of both the condensed first fluid loop and the cold tank fluid loop, condenses the vaporized first fluid in the closed loop back to a fluid state in preparation of being pumped again through the circuit.

A second plate heat exchanger 16 installed in the path of both the condensed first fluid loop and the hot tank fluid loop, flashes the condensed first fluid loop to a vapor creating pressure to be used to rotate a turbine. A first pressure tank 17, which may be of piston type or any style and combination of pressure retaining and pressure inducing technology that can be used to maintain a constant high pressure on the first fluid vapor as the first fluid flashes at varying speeds because of slight temperature changes in all the closed loops. For example, a pressure tank 17, 20 could be sequenced to receive pressure while another pressure tank is exhausting its pressure towards the turbine for a short duration of time. The pressure receiving time and the pressure exhausting time can be determined by the PLC 36. The PLC 36 can sense pressure and flow on the thermal loop 600 via pressure temperature sensors and alternate fill time and exhaust time as needed to maintain a constant pressure on the turbine.

A first pressure switch 18 measures pressure in the tank controlling solenoid valves 22 that direct the flow path of pressurized first fluid vapor to the pressure tank 20 or to the turbine 23. The PLC 36 can determine the sequence time as needed to maintain the highest amount of pressure possible to rotate the turbine. Two solenoid valves 22 direct the path of pressurized first fluid vapor as required by the PLC 36.

A second pressure tank 17, which may be of piston type or any style and combination of pressure retaining and pressure inducing technology that can be used to maintain a constant high pressure on the first fluid as the first fluid flashes at varying speeds because of slight temperature changes in all the closed loops. For example, a first pressure tank 20 may be sequenced to receive pressure while a second pressure tank 17 is exhausting its pressure towards the turbine 23 for a short duration of time. The pressure receiving time and the pressure exhausting time can be determined by the PLC 36. The PLC 36 can sense pressure and flow on the thermal loop 600 via pressure temperature sensors and alternate fill time and exhaust time as needed to maintain a constant pressure on the turbine 23.

A first pressure switch 21 and a second pressure switch 18 measure pressures in the pressure tanks 17, 20, controlling solenoid valves 22, 19 that direct the flow path of pressurized first fluid vapor to the pressure tanks 17, 20 or to the turbine 43. The PLC 36 can determine the sequence time as needed to maintain the highest amount of pressure possible to rotate the turbine. Two set of solenoid valves 22, 19 direct the path of pressurized first fluid vapor as required by the PLC 36.

The turbine 23 rotates by receiving pressurized and heated first fluid from the high pressure side of the first fluid closed loop and exhausting vapor to the low pressure side of the first fluid vapor loop. This turbine 23 can, itself, be a generator, as for example, the turbine can turn in magnetic bearings and incorporate magnets and copper coils as needed for the generation of electricity. Tesla turbine type technology or any other type of turbine technology can be incorporated or combined to most efficiently generate electricity. Alternatively, a separate generator 24 is coupled to the turbine output shaft. Generated electrical power can be used to provide the system with needed power. Excess electrical power generated can be used for power needs within a residence or other building, assist electrical requirements for making hydrogen, stored in batteries for future use, or sent to the utility grid in a net metering scenario.

A third pressure tank 25 is used to relieve or lower the pressure on the exhaust side of the turbine 23 to add to the turbine's torque and speed. The third pressure tank 25 may be the first storage tank 205a of FIGS. 2 and 3. The third pressure tank 25 may be sequenced to receive pressure while a fourth pressure tank 28 is exhausting pressure towards the pre-condensing and pre-heating heat exchanger 31 for a duration of time. The fourth pressure tank 28 may be the second storage tank 205b of FIGS. 2 and 3. The pressure receiving time and the pressure exhausting time of the pressure tanks 25, 28 can be determined by the PLC 36. The PLC 36 can sense pressure and flow on the thermal loop 600 via pressure temperature sensors and alternate fill time and exhaust time as needed to maintain the lowest pressure possible on the exhaust side of the turbine 23.

A third pressure switch 26 measures pressure in the third pressure tank 25, controlling solenoid valves 27 that direct the flow path of first fluid vapor to the third pressure tank 25 or to the pre-condensing and pre-heating heat exchanger 31. The PLC 36 can determine the sequence time as needed to maintain the lowest amount of pressure possible on the exhaust side of the turbine 23, thus creating more torque. A first pair of solenoid valves 27, 30 direct the path of first fluid vapor as required by the PLC 36.

A fourth pressure tank 28 is used to relieve or lower the pressure on the exhaust side of the turbine to add to the turbines torque and speed. The fourth pressure tank 28 may be sequenced to receive pressure while the third pressure tank 25 is exhausting its pressure towards the pre-condensing and pre-heating heat exchanger 31 for a controlled duration of time. The pressure receiving time and the pressure exhausting time of this pressure tank can be determined by the PLC 36. The PLC 36 can sense pressure and flow via pressure temperature sensors and alternate fill time and exhaust time as needed to maintain the lowest pressure possible on the exhaust side of the turbine 23.

A fourth pressure switch 29 measures pressure in the fourth pressure tank 28, controlling solenoid valves 30 that direct the flow path of first fluid vapor to the fourth pressure tank 28 or to the pre-condensing and pre-heating heat exchanger 31. The PLC 36 can determine the sequence time as needed to maintain the lowest amount of pressure possible on the exhaust side of the turbine 23, thus creating more torque. The second pair of solenoid valves 30 direct the path of pressurized first fluid vapor as required by the PLC 36.

The pre-condensing and pre-heating heat exchanger 31 helps equalize the temperature as two different first fluid flow paths merge and transfer their different temperatures through plates, achieving a more equal temperature. This pre-condensing and pre-heating function helps raise and lower temperatures in each flow path to enhance efficiency by pre-flashing the first fluid and pre-condensing the first fluid vapor. More efficiency is achieved on the entire heat transfer closed loop system by this temperature equalizing function, because it requires less heating from and heat loss to the hot tank 7 to vaporize the first fluid loop and less cooling from and heat gain to the cold tank 9 to condense the first fluid vapor in the closed loop back to a liquid.

A D.C. to A.C. inverter 32 can be installed to receive electricity from the generator (24) and change the D.C. electricity to a common building A.C. voltage. This smart inverter 32 can send excess electricity to the utility grid; integrate a charge controller to charge batteries storing electricity, and send power to the PLC 36. A standard charge controller 33 maintains a charge in the batteries 34, which can be sized and used to start the system in a stand alone off the grid application.

A battery bank 34 is sized to start the thermal loop 600 until the thermal loop 600 is generating electricity. Alternatively, utility power with net metering 35 can be used to start the thermal loop 600 until the thermal loop 600 is self generating and allow the system to sell excess electricity back the utility.

The PLC 36 is preferably used as the brains of the entire thermal loop 600 by monitoring and controlling all the functions described to achieve the highest efficiency and energy production possible. A cold fluid tank condensing loop 37 is used to condense the first fluid from vapor phase to liquid phase. A hot tank heating loop 38 is used to flash the first fluid to a pressurized gas, or vapor phase.

The following fluid states are indicated: second fluid 39 in its condensed fluid state; first fluid 40 in its pre-heated state; first fluid 99 maintained in its vaporized, high-pressure state; first fluid 41 maintained in its vaporized, low-pressure state; and second fluid 43 is in its pre-condensed state.

A mixture of water and antifreeze (such as propylene glycol) 44 is circulated in the ground below frost level at a relatively constant temperature. A fill valve 45 in the first fluid closed loop provides a way for first fluid to be injected into the system. A pressure relief valve can be used to relieve pressure from the first fluid closed loop if the loop over pressurizes.

A pressure reducing valve 47 can be used on the high pressure side of the first fluid closed loop to insure a consistent pressure to the turbine 23 to maintain a constant R.P.M and voltage as the turbine 23 rotates the generator 24. A shunt 46 can remove heated first fluid.

The electrical panel 48 can be in an existing building and wired to the system for 10 starting the cycle, net metering path and supplying electricity from the system to the building as needed. A generator 24 with a transfer switch can also be wired to the panel for system starting needs. Flow meters A throughout the system are used for control measures, they can be wired to the PLC 36 for flow and fluid volume sensing and controlling. On/Off valves B can 15 be manual or electric (i.e., they can be wired to the PLC 36 for flow controlling). Pressure temperature gages/sensors C can be used throughout the system for control measures, they can be wired to the PLC 36 for flow and fluid volume sensing and controlling. Check valves D can be used in the piping system to avoid back pressurization and direct the flow in each closed loop circuit.

The embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

LOOP THERMAL ENERGY SYSTEM

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CPC

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CROSS-REFERENCE TO RELATED APPLICATIONS

Provisional Applications (1)