阅读说明：本技术 地热热交换器、地热热装置以及用于将热能注入到大地中的方法 (Geothermal heat exchanger, geothermal heat device and method for injecting thermal energy into the ground ) 是由 R·尼米 于 2019-02-12 设计创作，主要内容包括：本发明涉及地热热交换器、地热热装置以及与地热热装置相关的方法。地热热交换器包括具有竖管(10、11)和排流管(20、21)的管装置(10、11、20、21)和布置到管装置(10、11、20、21)的第一泵(8)。竖管(10、11)和排流管(20、21)被布置成彼此流体连通,以使初级工作流体循环。竖管(10、11)沿竖管(10、11)的长度的至少一部分设置有围绕竖管(10、11)的第一隔热件(25),并且第一泵(8)被布置成使初级工作流体在朝向竖泵(10、11)的下端的方向上循环。(The present invention relates to geothermal heat exchangers, geothermal heat devices and methods relating to geothermal heat devices. The geothermal heat exchanger comprises a tube arrangement (10, 11, 20, 21) with a riser tube (10, 11) and a drain tube (20, 21) and a first pump (8) arranged to the tube arrangement (10, 11, 20, 21). The risers (10, 11) and drains (20, 21) are arranged in fluid communication with each other to circulate the primary working fluid. The riser duct (10, 11) is provided with a first thermal insulation (25) surrounding the riser duct (10, 11) along at least a part of the length of the riser duct (10, 11), and the first pump (8) is arranged to circulate the primary working fluid in a direction towards the lower end of the riser pump (10, 11).)

1. A geothermal heat exchanger, the geothermal heat exchanger comprising:

-a pipe arrangement (10, 11, 20, 21) for circulating a primary working fluid, said pipe arrangement (10, 11, 20, 21) comprising:

-a standpipe (10, 11), said standpipe (10, 11) having a lower end (17); and

a drain pipe (20, 21), the drain pipe (20, 21) having a lower end (13, 4),

the lower end (17) of the riser (10, 11) and the lower end of the drain pipe (20, 21) are arranged in fluid communication with each other for circulating the primary working fluid in a ground hole (2) along the riser (10, 11) and the drain pipe (20, 21), and the riser (10, 11) is arranged inside the drain pipe (20, 21);

-the riser pipe (10, 11) is provided with a first insulation (25) around the riser pipe (10, 11) along at least a part of the length of the riser pipe (10, 11); and

a first pump (8), the first pump (8) being arranged to the tube arrangement (10, 11, 20, 21),

the method is characterized in that:

-the riser pipe (10, 11) is arranged inside the drain pipe (20, 21) and the riser pipe (10, 11) extends out an extension distance (M) from the lower end (13) of the drain pipe (20, 21); and

-the first pump (8) is arranged to circulate the primary working fluid in a direction towards the lower end (17) of the standpipe (10, 11).

2. A geothermal heat exchanger according to claim 1, wherein:

-the first pump (8) is a reversible pump arranged to pump the primary working fluid in a direction towards the lower end (13) of the standpipe (10, 11) and towards an upper end (27) of the drain pipe (20, 21), or towards the lower end (13, 4) of the drain pipe (20, 21) and towards an upper end (7) of the standpipe (10, 11); and

-the geothermal heat exchanger comprises a control unit (60), the control unit (60) being connected to the first pump (8) and being arranged to control the direction of operation of the first pump (8) which is reversible.

3. A geothermal heat exchanger according to claim 1 or 2, wherein:

-the geothermal heat exchanger comprises a second pump (9), the second pump (9) being arranged to pump the primary working fluid in a direction towards the lower end (13, 4) of the drain pipe (20, 21) and towards the upper end (7) of the riser pipe (10, 11); and

-the geothermal heat exchanger comprises a control unit (60), the control unit (60) being connected to the first pump (8) and the second pump (9) and being arranged to control the operation of the first pump (8) and the second pump (9) to set the circulation direction of the primary working fluid.

4. A geothermal heat exchanger according to any one of claims 1 to 3, wherein:

-the standpipe (10, 11) is an evacuated duct comprising a vacuum layer surrounding the flow passage of the standpipe (10, 11), the vacuum layer being arranged to form the first thermal shield (25); or

-the riser pipe (10, 11) comprises a layer of insulating material on the outer surface of the riser pipe (10, 11), said layer of insulating material being arranged to form said first insulation (25); or

-the riser pipe (10, 11) comprises a layer of insulating material on the inner surface of the riser pipe (10, 11), which layer of insulating material is arranged to form the first thermal insulation (25).

5. A geothermal heat exchanger according to any one of claims 1 to 4, wherein:

-said first thermal insulation (25) extends along the entire length of said stack (10, 11); or

-the first thermal insulation (25) extends from the upper end (7) of the riser duct (10, 11) along at least 50% of the length (L) of the riser duct (10, 11) or at least 2/3 of the length (L) of the riser duct (10, 11) towards the lower end (17) of the riser duct (10, 11); or

-said first thermal insulation (25) extends from a predetermined distance (O) from said lower end (17) of said riser pipe (10, 11) along said riser pipe (10, 11) towards said upper end (7) of said riser pipe (10, 11), said predetermined distance (O) from said lower end (17) of said riser pipe (10, 11) being at least 10% of the length (L) of said riser pipe (10, 11) or at least 20% of the length (L) of said riser pipe (10, 11); or

-said first thermal insulation (25) extends along said riser duct (10, 11) between said upper end (7) and said lower end (17, 4) of said riser duct (10, 11), and from a predetermined distance (O) from said lower end (17) of said riser duct (10, 11) along said riser duct (10, 11) towards said upper end (7) of said riser duct (10, 11), and from a predetermined distance (O) from said upper end (7) of said riser duct (10, 11) towards said lower end (17) of said riser duct (10, 11).

6. A geothermal heat exchanger according to any one of claims 1 to 5, wherein:

-the thermal conductivity of the first thermal insulation (25) is uniform in the direction along the riser (10, 11); or

-the thermal conductivity of the first thermal insulation (25) decreases in a direction towards the lower end (17) of the riser pipe (10, 11); or

-the thickness of the first thermal insulation (25) decreases in a direction towards the lower end (17) of the riser pipe (10, 11), such that the thermal conductivity of the first thermal insulation (25) decreases in a direction towards the lower end (17) of the riser pipe (10, 11); or

-the first insulation (25) comprises at least two different insulation materials arranged to the riser pipe (10, 11) such that the thermal conductivity of the first insulation (25) decreases in a direction towards the lower end (17) of the riser pipe (10, 11).

7. A geothermal heat apparatus comprising:

-a ground hole (2), the ground hole (2) being provided into the ground and extending from the ground (1) into the ground, the ground hole (2) having a lower end (4);

-a pipe arrangement (10, 11, 20, 21), said pipe arrangement (10, 11, 20, 21) comprising a riser pipe (10, 11) having a lower end (17) and being arranged into the ground hole (2) and a drain pipe (2, 20, 21) having a lower end (4, 13), said lower end (17) of the riser pipe (10, 11) and said lower end (4, 13) of the drain pipe (2, 20, 21) being arranged in fluid communication with each other for circulating a primary working fluid in the ground hole (2);

-the riser pipe (10, 11) is provided with a first insulation (25) around the riser pipe (10, 11) along at least a part of the length of the riser pipe (10, 11);

-a first pump (8), said first pump (8) being connected to said pipe arrangement (10, 11, 20, 21) and being arranged to circulate said primary working fluid in said standpipe (10, 11); and

-a heat exchange connection (30), said heat exchange connection (30) being connected with said tube means (10, 11, 20, 21) for a secondary heat exchange with said primary working fluid,

the method is characterized in that:

-the first pump (8) is arranged to circulate the primary working fluid in a direction that is: in the riser pipe (10, 11) towards the lower end (4) of the ground hole (2) and in the drain pipe (20, 21) towards the ground (1).

8. The geothermal thermal apparatus according to claim 7, wherein:

-the ground hole (2) forms at least a part of the drain pipe (2, 20, 21) for circulating the primary working fluid in the ground hole (2);

-the pipe arrangement (10, 11, 20, 21) comprises a separate drain pipe (20, 21), the separate drain pipe (20, 21) having a lower end (13) arranged into the ground hole (2), the lower end (17) of the riser pipe (10, 11) and the lower end (13) of the separate drain pipe (20, 21) being arranged in fluid communication with each other for circulating the primary working fluid in the ground hole (2), the riser pipe (10, 11) being arranged inside the separate drain pipe (20, 21); or

-the pipe arrangement (10, 11, 20, 21) comprises a separate drain pipe (20, 21), the separate drain pipe (20, 21) having a lower end (13) arranged into the ground hole (2), the lower end (17) of the riser pipe (10, 11) and the lower end (13) of the separate drain pipe (20, 21) being arranged in fluid communication with each other for circulating the primary working fluid in the ground hole (2); and

-the riser pipe (10, 11) is arranged inside the separate drain pipe (20, 21) in the ground hole (2), and the riser pipe (10, 11) extends out an extension distance (M) from the lower end (13) of the drain pipe (20, 21) towards the lower end (4) of the ground hole (2); or

-the pipe arrangement (10, 11, 20, 21) comprises a separate drain pipe (20, 21), the separate drain pipe (20, 21) having a lower end (13) arranged into the ground hole (2), the lower end (17) of the riser pipe (10, 11) and the lower end (13) of the separate drain pipe (20, 21) being arranged in fluid communication with each other for circulating the primary working fluid in the ground hole (2); and

-the separate drainage pipe (20, 21) extends from the ground (1) into the ground hole (2) to a free distance (P) from the lower end (4) of the ground hole (2), such that the ground hole (2) forms the drainage pipe from the lower end of the ground hole (2) along the free distance (P); or

-the ground hole (2) forms the drain pipe (20, 21) and the riser pipe is arranged inside the ground hole (2, 20, 21).

9. The geothermal heat apparatus according to claim 7 or 8, wherein:

-the standpipe (10, 11) is an evacuated duct comprising a vacuum layer surrounding the flow passage of the standpipe (10, 11), the vacuum layer being arranged to form the first thermal shield (25); or

-the riser pipe (10, 11) comprises a layer of insulating material on the outer surface of the riser pipe (10, 11), said layer of insulating material being arranged to form said first insulation (25); or

-the riser pipe (10, 11) comprises a layer of insulating material on the inner surface of the riser pipe (10, 11), which layer of insulating material is arranged to form the first thermal insulation (25).

10. The geothermal heat apparatus according to any one of claims 7 to 9, wherein:

-the first thermal insulation (25) extends from the ground (1) along the riser pipe (10, 11) towards the lower end (4) of the ground hole (2) and to at least 50% of the depth (D) of the ground hole (2) or at least 2/3 of the depth (D) of the ground hole (2); or

-said first thermal insulation (25) extends upwards along said riser (10, 11) from said lower end (4) of said ground hole (2) at a predetermined distance (E) from said lower end (4) of said ground hole (2), said predetermined distance (E) from said lower end (4) of said ground hole (2) being at least 10% of the depth (D) of said ground hole (2) or at least 20% of the depth (D) of said ground hole (2); or

-said first thermal insulation (25) extends along said riser (10, 11) between the ground (1) and said lower end (4) of said ground hole (2), along said riser (10, 11) towards the ground (1) along said riser (10, 11) at a predetermined distance (E) from said lower end (4) of said ground hole (2), and from a predetermined distance (E) from the ground (1) towards said lower end (4) of said ground hole (2).

11. The geothermal heat apparatus according to any one of claims 7 to 10, wherein:

-the thermal conductivity of the first thermal insulation element (25) is uniform in the direction along the ground hole (2); or

-the thermal conductivity of the first thermal insulation element (25) decreases in a direction towards the lower end (4) of the ground hole (2); or

-the thickness of the first thermal insulation element (25) decreases in a direction towards the lower end (4) of the ground hole (2), such that the thermal conductivity of the first thermal insulation element (25) decreases in a direction towards the lower end (4) of the ground hole (2); or

-the first insulation (25) comprises at least two different insulation materials arranged to the riser pipe (10, 11) such that the thermal conductivity of the first insulation (25) decreases in a direction towards the lower end (4) of the ground hole (2).

12. The geothermal heat apparatus according to any one of claims 7 to 11, wherein:

-the first pump (8) is a reversible pump arranged to pump the primary working fluid in a direction such that: a direction upwards in the riser pipe (10, 11) towards the lower end (4) of the ground hole (2) and in the discharge pipe (20, 21) towards the ground (1), or a direction upwards in the discharge pipe (20, 21) towards the lower end (4) of the ground hole (2) and in the riser pipe (10, 11) towards the ground (1), and comprising a control unit (60), which control unit (60) is connected to the first pump (8) and arranged to control the operational direction of the reversible first pump (8); or

-the geothermal heat means comprise a second pump (9), the second pump (9) being arranged to pump the primary working fluid in a direction such that: in the discharge pipe (20, 21) towards the lower end (4) of the ground bore (2) and upwards in the riser pipe (10, 11) towards the ground (1), and comprising a control unit (60), the control unit (60) being connected to the first pump (8) and the second pump (9), the control unit (60) being arranged to control the operation of the first pump (8) and the second pump (9) to set the circulation direction of the primary working fluid.

13. The geothermal thermal apparatus according to claim 12, wherein:

-the control unit (60) is connected to a heat exchange connection (30) and is arranged to operate the first pump (8), or the first pump (8) and the second pump (9), in response to an operating condition of the heat exchange connection (30); or

-the geothermal heat device comprises a timer (73) connected to the control unit (60), and the control unit (60) is arranged to operate the first pump (8), or the first pump (8) and the second pump (9), in response to a timer input from the timer (73); or

-the geothermal heat means comprises at least one temperature sensor (71, 75, 77) connected to the control unit (60), and the control unit (60) is arranged to operate the first pump (8), or the first pump (8) and the second pump (9), in response to a temperature input from the temperature sensor (71, 75, 77); or

-the control unit (60) is connected to an external data server (102) with a data transfer connection (100), and the control unit (60) is arranged to operate the first pump (8), or to operate the first pump (8) and the second pump (9), in response to data input from the external data server (102).

14. Geothermal heat installation according to any one of claims 7 to 13, characterized in that the depth of the ground hole (2) is at least 300 meters, or at least 500 meters, or between 300 and 3000 meters.

15. The geothermal heat apparatus of any one of claims 7 to 14, wherein the apparatus comprises:

-a heat pump (30), said heat pump (30) being connected to said tube arrangement (10, 11, 20, 21) and being arranged to provide said heat exchange connection (30) for said secondary heat exchange with said primary working fluid;

-a heat pump (30), said heat pump (30) being connected to said tube arrangement (10, 11, 20, 21) and being arranged to provide said heat exchange connection (30) for said secondary heat exchange with said primary working fluid;

-the heat pump (30) is arranged to release thermal energy to the primary working fluid to heat the primary working fluid; and

-the first pump (8) is arranged to circulate the heated primary working fluid in the riser pipe (10, 11) in a direction towards the lower end (4) of the earth bore (2); or

-a heat exchanger (30), said heat exchanger (30) being connected to said tube arrangement (10, 11, 20, 21) and being arranged to provide said heat exchange connection (30) for said secondary heat exchange with said primary working fluid;

-a heat exchanger (30), said heat exchanger (30) being connected to said tube arrangement (10, 11, 20, 21) and being arranged to provide said heat exchange connection (30) for said secondary heat exchange with said primary working fluid;

-the heat exchanger (30) is arranged to release thermal energy to the primary working fluid to heat the primary working fluid; and

-the first pump (8) is arranged to circulate the heated primary working fluid in the riser pipe (10, 11) in a direction towards the lower end (4) of the earth bore (2).

16. The geothermal thermal apparatus according to claim 15, wherein:

-the heat pump (30) is arranged to extract thermal energy from the primary working fluid to cool the primary working fluid; and

-the first pump (8) is arranged to circulate the primary working fluid from the lower end (4) of the ground hole (2) in a direction up the riser pipe (10, 11).

17. A method for injecting thermal energy into the earth, the method comprising:

-circulating a primary working fluid in a geothermal heat exchanger, the geothermal heat exchanger comprising a pipe arrangement (10, 11, 20, 21), the pipe arrangement (10, 11, 20, 21) having a drain pipe (2, 20, 21) and a riser pipe (10, 11) arranged into a ground hole (2), the riser pipe (10, 11) and the drain pipe (20, 21) being arranged in fluid communication with each other for circulating the primary working fluid in the ground hole (2) for geothermal heat exchange in the ground hole (2), the ground hole (2) extending from the ground (1) into the ground and having a lower end (4), the riser pipe (10, 11) being provided with a first thermal insulation (25) surrounding the riser pipe (10, 11) along at least a part of the length of the riser pipe (10, 11); and

-providing heat exchange between a secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger,

characterized in that the method comprises:

-operating the geothermal heat exchanger in an injection mode in which the primary working fluid receives thermal energy from the secondary working fluid in the heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger; and

-in the injection mode, circulating the primary working fluid in a downward direction in the riser pipe (10, 11) and in an upward direction in the drain pipe (20, 21) to transfer thermal energy to the lower end (4) of the earth bore (2) and to release thermal energy from the primary working fluid to the ground at the lower end of the earth bore (2).

18. The method of claim 17, wherein the method comprises:

-operating the geothermal heat exchanger in an extraction mode in which the primary working fluid releases thermal energy to the secondary working fluid in the heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger; and

-in the extraction mode, circulating the primary working fluid in a downward direction in the discharge pipes (20, 21) and in an upward direction in the risers (10, 11) to transport thermal energy from the ground hole (2) and to release thermal energy from the primary working fluid to the secondary working fluid in the heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger.

19. The method of claim 18, wherein the method comprises:

-controlling the operation of the geothermal heat exchanger between the extraction mode and the injection mode based on temperature measurements in the earth or in the earth hole (2); or

-controlling the operation of the geothermal heat exchanger between the extraction mode and the injection mode based on temperature measurements (75, 77) of the primary working fluid in the riser duct (10, 11) or in the discharge duct (20, 21) or in the riser duct (10, 11) and in the discharge duct (20, 21); or

-controlling the operation of the geothermal thermal apparatus between the extraction mode and the injection mode based on the temperature measurement of the secondary working fluid; or

-controlling the operation of the geothermal heat exchanger between the extraction mode and the injection mode based on a temperature measurement (71) inside a building (50) or in the ambient atmosphere of the building, the geothermal heat exchanger being arranged in connection with the building (50); or

-controlling the operation of the geothermal heat exchanger between the extraction mode and the injection mode based on a predetermined operation plan; or

-controlling operation of the geothermal heat exchanger between the extraction mode and the heating mode based on external input data from an external data server (102).

20. The method according to any one of claims 17 to 19, characterized in that the method comprises:

-using waste heat of a ventilation system of a building (50) as a source for heating the secondary working fluid; or

-using thermal energy of an industrial plant, power generation plant or manufacturing plant as a source for heating the secondary working fluid; or

-utilizing excess thermal energy of a data server facility or a municipal heat source as a source for heating the secondary working fluid; or

-generating thermal energy by using wind, water or solar power to heat the secondary working fluid.

21. The method according to any one of claims 17 to 20, comprising providing said heat exchange between a secondary working fluid in a heat pump (30) and said primary working fluid circulating in said geothermal heat exchanger, said method further comprising:

-operating the heat pump in a cooling mode in which the primary working fluid receives thermal energy from the secondary working fluid in the heat pump (30) and operating the geothermal heat exchanger in the injection mode; or

-operating the heat pump in a heating mode in which the secondary working fluid receives heat energy from the primary working fluid in the heat pump (30) and operating the geothermal heat exchanger in the extraction mode; or

-operating the heat pump in a cooling mode in which the primary working fluid receives thermal energy from the secondary working fluid in the heat pump (30) and operating the geothermal heat exchanger in the injection mode; and is

-operating the heat pump in a heating mode in which the secondary working fluid receives thermal energy from the primary working fluid in the heat pump (30) and operating the geothermal heat exchanger in the extraction mode.

22. A method according to any one of claims 17 to 21, comprising circulating the primary working fluid in a geothermal heat exchanger according to any one of claims 1 to 6 or in a geothermal heat apparatus according to any one of claims 7 to 16.

Technical Field

The present invention relates to geothermal heat exchangers and more particularly to geothermal heat exchangers according to the preamble of claim 1. The invention also relates to a geothermal heat device and more particularly to a geothermal heat device according to the preamble of claim 7. The invention also relates to a method for injecting thermal energy into the ground, and more particularly to a method according to the preamble of claim 17.

Background

Ground source or geothermal heat exchangers are well known for extracting heat from the ground. This is implemented by utilizing the temperature difference in the ground and at the level above the ground. When deep into the earth, the temperature in the earth generally increases.

The ground source heat exchanger includes pipe means for circulating the primary working fluid. The pipe arrangement generally comprises a closed loop pipe having a riser pipe and a drainage pipe arranged in a borehole or ground hole or cavity in the ground. The tube arrangement is also connected to a heat exchanger on the ground to release heat from the primary working fluid. As the primary working fluid flows down the drain into the borehole, heat is extracted from the earth into the primary working fluid, and the temperature of the primary working fluid increases. The circulation of the primary working fluid carries the extracted heat from the borehole in the earth into the standpipe, and the primary working fluid then releases the heat to the secondary working fluid in the heat exchanger.

One of the disadvantages associated with the prior art is that the temperature of the primary working fluid gradually increases as it flows in the drain towards the bottom of the borehole, and similarly, the temperature of the primary working fluid decreases as it flows in the standpipe towards the surface. Additionally, the temperature of the primary working fluid shifts towards the average temperature due to unintentional heat exchange between the heated primary working fluid flowing in the standpipe and the cooled primary working fluid flowing in the drain pipe. Accordingly, the heated primary working fluid releases heat to the primary working fluid flowing down the drain and also to the ground surrounding the borehole, and therefore the temperature of the heated working fluid decreases towards the heat pump typically disposed above the ground. This reduces the efficiency of the ground source heat exchanger.

Additionally, it has been recognized that as heat is extracted from the earth, the temperature of the earth around the earth's borehole, particularly in the vicinity of the lower end of the earth's borehole, decreases. The reduction in temperature of the earth around the earth hole also reduces the heat extraction rate and efficiency of the source heat exchanger over time.

Disclosure of Invention

It is an object of the present invention to provide a geothermal heat exchanger, a geothermal heat apparatus and a method in connection with a geothermal heat apparatus that solves or at least alleviates the drawbacks of the prior art.

The object of the invention is achieved by a geothermal heat exchanger, which is characterized by what is stated in the independent claim 1. The object of the invention is also achieved by a geothermal device, which is characterized by what is stated in the independent claim 7. The object of the invention is also achieved by a method in connection with a geothermal heat installation, which is characterized by what is stated in the independent claim 17.

Preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of providing a geothermal heat exchanger comprising tube means for circulating a primary working fluid. The pipe arrangement comprises a riser pipe having a lower end and a drain pipe having a lower end. The lower end of the standpipe and the lower end of the drain pipe may be disposed in fluid communication with each other to circulate the primary working fluid in the earth bore along the standpipe and the drain pipe. The standpipe may be disposed inside the drain pipe. The geothermal heat exchanger further comprises a first pump arranged to the tube arrangement.

According to the invention, the riser pipe may be provided with a first insulation surrounding the riser pipe along at least a part of its length, and the first pump is arranged to circulate the primary working fluid in a direction towards the lower end of the riser pipe. This allows the primary working fluid to be circulated to the lower portion or end of the standpipe and also to the lower portion or end of the ground bore so that heat transfer from the primary working fluid is reduced or minimized.

The riser and the drain pipe may be arranged coaxially such that the riser is arranged inside the drain pipe. The length of the first insulation extending along the first insulation reduces or minimizes heat transfer between the standpipe and the drain pipe. The standpipe may be arranged inside the drain pipe such that the standpipe extends out an extension distance from a lower end of the drain pipe.

The first pump may be a reversible pump arranged to pump the primary working fluid in a direction down the standpipe and up the drain pipe, or in a direction down the drain pipe and up the standpipe. The geothermal heat exchanger may further comprise a control unit connected to the first pump and arranged to control the direction of operation of the reversible first pump.

Alternatively, the geothermal heat exchanger may comprise a second pump arranged to pump the primary working fluid in a direction down the drain pipe and up the riser pipe. The geothermal heat exchanger may further comprise a control unit connected to the first pump and the second pump and arranged to control operation of the first pump and the second pump to set a direction of circulation of the primary working fluid.

A standpipe is an evacuated tube that includes a vacuum layer surrounding the flow passage of the standpipe. The vacuum layer is arranged to form a first thermal shield. The evacuated tubes provide high efficiency thermal insulation, thereby minimizing heat transfer from the primary working fluid.

Alternatively or additionally, the standpipe may include a layer of insulating material on an outer surface of the standpipe. The layer of insulating material may be arranged to form a first thermal shield. The insulating layer can be varied in the length direction of the first tube so that the thermal insulation efficiency or thermal conductivity from the first tube can be varied.

The first thermal shield can extend along the entire length of the standpipe. This reduces heat exchange along the entire length of the stack. Alternatively, the first insulation may extend from the upper end of the standpipe along at least 50% of the length of the standpipe or at least 2/3 of the length of the standpipe toward the lower end of the standpipe. Further alternatively, the first thermal shield may extend upwardly along the standpipe from a predetermined distance from the lower end of the standpipe. The predetermined distance from the lower end of the standpipe may be at least 10% of the length of the standpipe or at least 20% of the length of the standpipe. Still alternatively, the first insulation can extend along the standpipe between the upper and lower ends of the standpipe and from a predetermined distance from the lower end of the standpipe along the standpipe toward the upper end of the standpipe and from a predetermined distance from the upper end of the standpipe toward the lower end of the standpipe. Thus, heat transfer from the primary working fluid circulating down the standpipe occurs at the lower end or portion of the standpipe, and thus at the lower portion of the ground hole.

The thermal conductivity of the first thermal shield can be uniform along the standpipe. This can be achieved with a first insulation that is uniform in the direction along the stack.

Alternatively, the thermal conductivity of the first thermal shield may be arranged to decrease in a direction towards the lower end of the riser. The thickness of the first thermal shield can decrease in a direction toward the lower end of the standpipe, such that the thermal conductivity of the first thermal shield decreases in a direction toward the lower end of the standpipe. The reduction of the thermal conductivity may also be achieved by the first insulation comprising at least two different insulation materials arranged to the riser pipe such that the thermal conductivity of the first insulation decreases in a direction towards the lower end of the riser pipe.

The invention also relates to a geothermal heat device comprising a pipe arrangement and a ground hole arranged into the ground and extending downwards from the ground. The pipe arrangement comprises a riser pipe having a lower end and being arranged into the ground hole and a drain pipe having a lower end. The lower end of the standpipe and the lower end of the drain pipe may be disposed in fluid communication with one another to circulate the primary working fluid in the earth bore. The standpipe can be provided with a first thermal shield surrounding the standpipe along at least a portion of the length of the standpipe. The apparatus further comprises a first pump connected to the pipe arrangement and arranged to circulate the primary working fluid in the riser pipe, and a heat exchange connection connected to the pipe arrangement for secondary heat exchange with the primary working fluid.

The heat exchange connection may be any heat source capable of releasing thermal energy or heat to the primary working fluid and/or capable of releasing thermal energy to the primary working fluid such that the temperature of the primary working fluid may be increased. The heat exchange connection is arranged or provided outside the ground opening to the tube arrangement or is connected to the tube arrangement outside the ground opening. This means that the heat exchange connection is provided to the pipe arrangement between the riser pipe and the drainage pipe outside the ground opening. The heat exchange connection may comprise a heat pump, heat exchanger or similar device arranged to provide heat exchange with the primary working fluid flowing in the tube arrangement. The heat exchange connection may be a building heat exchange connection such that the geothermal heat exchanger is arranged to receive thermal energy from or release energy to the building. Alternatively, the heat exchange connection may be a heat source heat exchange connection. The heat source may be an industrial heat source that releases waste heat or heat, an energy plant thermal connection, a district heating connection, or some heat source connection such as a data center waste heat connection.

In a preferred embodiment, the geothermal heat means comprises a heat pump for providing a heat exchange connection. The heat pump is capable of releasing thermal energy to the primary working fluid and is also capable of receiving thermal energy from the heat pump or a secondary working fluid in the heat pump.

According to the invention, the first pump is arranged to circulate the primary working fluid in a direction such that: in the riser towards the lower end of the ground hole and in the drainage pipe towards the ground. Accordingly, the primary working fluid and the thermal energy of the primary working fluid can be transferred to the lower end and the lower portion of the earth hole.

The standpipe can be an evacuated tube that includes a vacuum layer surrounding the flow passage of the standpipe. The vacuum layer may be arranged to form a first thermal shield. The evacuated tube provides excellent thermal insulation, allowing for effective prevention of thermal energy from escaping from the primary working fluid in the standpipe. Alternatively, the standpipe may include a layer of insulating material on the outer surface or on the inner surface of the standpipe. The layer of insulating material may be arranged to form a first thermal shield. The layer of insulating material may vary along the length of the standpipe.

The first insulation may extend from the surface along the riser towards the lower end of the earth bore and to at least 50% of the depth of the earth bore or at least 2/3 of the depth of the earth bore. Alternatively, the first insulator may extend upwardly along the riser pipe from a predetermined distance from the lower end of the ground hole. The predetermined distance from the lower end of the earth hole may be at least 10% of the depth of the earth hole or at least 20% of the depth of the earth hole.

The thermal conductivity of the first thermal shield may be uniform in a direction along the earth hole. This can be achieved with evacuated tubes or layers of insulating material that are uniform in the direction along the earth's bore. This allows efficient transfer of thermal energy to the lower part of the earth hole.

The thermal conductivity of the first thermal shield may also decrease in a direction toward the lower end of the ground hole. This may be achieved such that the thickness of the first thermal shield decreases in a direction towards the lower end of the ground hole, such that the thermal conductivity of the first thermal shield decreases in a direction towards the lower end of the ground hole. Alternatively, the first insulation may comprise at least two different insulation materials arranged to the riser pipe such that the thermal conductivity of the first insulation decreases in a direction towards the lower end of the ground hole. This may allow for longer heat transfer times of the primary working fluid in the earth bore over a wider area and save on insulation material.

The first pump may be a reversible pump arranged to pump the primary working fluid in a direction that is: towards the lower end of the ground opening in the riser pipe and in an upward direction from the ground in the drainage pipe, or towards the lower end of the ground opening in the drainage pipe and in an upward direction from the ground in the riser pipe. The geothermal heat device may further comprise a control unit connected to the first pump and arranged to control the direction of operation of the reversible first pump. This provides a simple structure in which one pump can be used for operation.

Alternatively, the geothermal device may comprise a second pump arranged to pump the primary working fluid in a direction that: towards the lower end of the ground hole in the drain pipe and upwards towards the ground in the riser pipe. The geothermal heat device may further comprise a control unit connected to the first pump and the second pump, the control unit being arranged to control operation of the first pump and the second pump to set a direction of circulation of the primary working fluid. Thus, the first and second pumps may not operate simultaneously to set a desired circulation direction of the primary working fluid.

The control unit may be connected to the heat exchange connection and arranged to operate the first pump, or to operate the first and second pumps, in response to an operating condition of the heat exchange connection. Alternatively, the geothermal device comprises a timer connected to the control unit, and the control unit may be arranged to operate the first pump, or to operate the first and second pumps, in response to a timer input from the timer. Furthermore, the geothermal device may comprise at least one temperature sensor connected to the control unit, and the control unit may be arranged to operate the first pump, or to operate the first and second pumps, in response to a temperature input from the temperature sensor. Further alternatively, the control unit may be connected to an external data server with a data transfer connection, and the control unit may be arranged to operate the first pump, or to operate the first and second pumps, in response to data input from the external data server. Accordingly, the operation of the first pump or the first and second pumps and the geothermal heat device may be controlled in response to predetermined thermal conditions, a predetermined operating plan, or in response to data input from an external data server.

The vertical riser may be arranged inside the drainage pipe inside the ground hole. Furthermore, the ground hole may form a drain pipe or at least a part of a drain pipe, and the riser pipe is arranged inside the ground hole. When the riser pipe is arranged inside the drainage pipe, the cross-sectional area of the ground hole is effectively used, and geothermal heat transfer can be effectively utilized. This is particularly advantageous in earth holes having a depth equal to or greater than 300 meters.

In one embodiment, the ground bore may form at least a portion of a drain pipe to circulate the primary working fluid in the ground bore.

Alternatively, the pipe arrangement may comprise a separate drain pipe having a lower end arranged into the ground hole. The lower end of the standpipe and the lower end of the separate drainage pipe may be arranged in fluid communication with each other for circulating the primary working fluid in the earth bore, the standpipe being arranged inside the separate drainage pipe.

In another alternative embodiment, the pipe arrangement may comprise a separate drain pipe having a lower end arranged into the earth hole. The lower end of the standpipe and the lower end of the separate drain pipe are arranged in fluid communication with each other to circulate the primary working fluid in the earth's bore. The riser pipe is also arranged inside a separate drainage pipe in the ground hole and extends out an extension distance from the lower end of the drainage pipe towards the lower end of the ground hole.

In yet another alternative embodiment, the pipe arrangement may comprise a separate drain pipe having a lower end arranged into the earth hole. The lower end of the standpipe and the lower end of the separate drain pipe are arranged in fluid communication with each other to circulate the primary working fluid in the earth's bore. The individual drainage pipes extend from the ground into the ground hole to a free distance from the lower end of the ground hole, so that the ground hole forms a drainage pipe along the free distance from the lower end of the ground hole.

Additionally, the ground hole may also form substantially the entire drain pipe, and the riser pipe is arranged inside the ground hole.

Furthermore, the standpipe may be arranged inside the drainage pipe in the ground hole such that the standpipe extends out an extension distance from the lower end of the drainage pipe towards the lower end of the ground hole. Alternatively, the drainage pipe may extend from the ground into the ground hole to a free distance from the lower end of the ground hole, so that the ground hole may be formed along the free distance from the lower end of the ground hole. Accordingly, the ground hole may form at least a part of the drain pipe, and the standpipe is arranged inside the ground hole. In this manner, the ground hole forms a drainpipe at the lower end of the ground hole, maximizing heat transfer between the primary working fluid and the ground surrounding the lower end of the ground hole because the primary working fluid is in direct contact with the ground surrounding the lower end of the ground hole.

The depth of the earth's bore may be at least 300 meters, or at least 500 meters, or between 300 meters and 3000 meters, or between 300 meters and 5000 meters. In the present invention, geothermal heat exchangers, geothermal heat devices and methods are particularly suitable for use in connection with deep ground holes.

The apparatus may further comprise a heat pump connected to the tube means and arranged to provide a heat exchange connection for secondary heat exchange with the primary working fluid.

Alternatively, the apparatus may comprise a heat pump connected to the tube means and arranged to provide a heat exchange connection for secondary heat exchange with the primary working fluid. The heat pump is arranged to release thermal energy to the primary working fluid to heat the primary working fluid, and the first pump is arranged to circulate the heated primary working fluid in the standpipe in a direction towards the lower end of the earth bore. Thus, the heat pump is operated in a cooling mode in which thermal energy is released to the primary working fluid or the primary working fluid extracts thermal energy in the heat pump.

Further alternatively, the apparatus may comprise a heat exchanger connected to the tube means and arranged to provide a heat exchange connection for secondary heat exchange with the primary working fluid.

In a further alternative embodiment, the apparatus may comprise a heat exchanger connected to the tube means and arranged to provide a heat exchange connection for secondary heat exchange with the primary working fluid. A heat exchanger is arranged to release thermal energy to the primary working fluid to heat the primary working fluid, and a first pump is arranged to circulate the heated primary working fluid in the standpipe in a direction towards the lower end of the earth bore.

Additionally, the heat pump may be arranged to extract thermal energy from the primary working fluid to cool the primary working fluid, and the first pump may be arranged to circulate the primary working fluid from the lower end of the ground bore in a direction up the standpipe. Thus, the heat pump is operated in a heating mode in which thermal energy is released from the primary working fluid in the heat pump.

The invention also relates to a method for injecting thermal energy into the ground or into the ground opening of a geothermal device. The method includes circulating a primary working fluid in a geothermal heat exchanger, the geothermal heat exchanger comprising a tube arrangement having a drain tube and a riser tube arranged into the earth bore, the riser tube and the drain tube being arranged in fluid communication with each other to circulate the primary working fluid in the earth bore for geothermal heat exchange in the earth bore. The ground hole extends from the ground into the ground and has a lower end. The standpipe is provided with a first thermal shield surrounding the standpipe along at least a portion of the length of the standpipe. The method also includes providing heat exchange between the secondary working fluid and a primary working fluid circulating in the geothermal heat exchanger. The method includes operating the geothermal heat exchanger in an injection mode and circulating a primary working fluid in a downward direction in the standpipe and in an upward direction in the drain pipe in the injection mode to deliver thermal energy to the lower end of the earth bore and to release thermal energy from the primary working fluid to the earth at the lower end of the earth bore, the primary working fluid receiving thermal energy from the secondary working fluid in heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger in the injection mode. The method allows thermal energy to be transported from the secondary working fluid to the lower end of the earth bore by heat exchange from the primary working fluid and to be injected into the earth around the lower end of the earth bore.

The method may further include operating the geothermal heat exchanger in an extraction mode and circulating the primary working fluid in a downward direction in the exhaust pipe and in an upward direction in the standpipe to transport thermal energy from the earth bore and release thermal energy from the primary working fluid to the secondary working fluid in heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger in the extraction mode, the primary working fluid releasing thermal energy to the secondary working fluid in heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger in the extraction mode. Accordingly, the thermal energy injected to the lower end of the earth bore may be extracted from the earth and used to heat the secondary working fluid.

The method may further comprise controlling operation of the geothermal heat exchanger between an extraction mode and an injection mode based on temperature measurements in the earth or borehole. Alternatively, the method may comprise controlling operation of the geothermal heat exchanger between the extraction mode and the injection mode based on a temperature measurement of the primary working fluid in the first pipe or the drain or in the riser and the drain, or based on a temperature measurement of the secondary working fluid. Still alternatively, the method may comprise controlling operation of a geothermal heat exchanger between an extraction mode and an injection mode, the geothermal heat exchanger being arranged in connection with the building, based on a temperature measurement inside the building or in an ambient atmosphere of the building. Further, the method may include controlling operation of the geothermal heat exchanger between the extraction mode and the injection mode based on a predetermined operation schedule with respect to external input data from an external data server. The external input data may be, for example, meteorological data from an external meteorological server, or electrical or thermal data from a power generation plant or an electrical or thermal network. Thus, the method may be used in either the extraction mode or the injection mode, based on operating conditions or temperature conditions or other external conditions.

The method may further comprise using waste heat of a ventilation system of the building as a source for heating the secondary working fluid, or using thermal energy of an industrial, power generation or manufacturing plant as a source for heating the secondary working fluid, or using waste heat energy of a data server facility or a municipal heat source as a source for heating the secondary working fluid, or generating thermal energy by using wind, water or solar power to heat the secondary working fluid.

The method may further comprise providing heat exchange in the heat pump between the secondary working fluid and a primary working fluid circulating in a geothermal heat exchanger. The method may then include operating the heat pump in a cooling mode in which the primary working fluid receives thermal energy from the secondary working fluid in the heat pump and operating the geothermal heat exchanger in an injection mode. Alternatively, the method may include operating the heat pump in a heating mode in which the secondary working fluid receives thermal energy from the primary working fluid in the heat pump and operating the geothermal heat exchanger in an extraction mode. Further alternatively, the method may include operating the heat pump in a cooling mode in which the primary working fluid receives thermal energy from the secondary working fluid in the heat pump and operating the geothermal heat exchanger in an injection mode in which the secondary working fluid receives thermal energy from the primary working fluid in the heat pump and operating the heat pump in an extraction mode in which the secondary working fluid receives thermal energy from the primary working fluid in the heat pump. Accordingly, the combination of the cooling and heating modes of the heat pump and the heat injection and extraction modes of the geothermal heat exchanger allow for the storage of thermal energy in the earth's borehole and the exploitation of earth's borehole heat, respectively.

An advantage of the present invention is that it enables heat to be transferred from the primary working fluid to the lower end or portion of the earth bore with reduced heat exchange or loss during flow of the primary working fluid in the at least partially insulated riser. Thus, heat may be injected into the ground surrounding the ground hole at the lower end of the ground hole. Thus, the invention enables thermal energy to be stored to the ground and to the lower end of the ground hole for later extraction.

Drawings

The invention is described in detail by means of specific embodiments with reference to the attached drawings, in which:

fig. 1 shows a schematic diagram of a ground source heat exchanger of the prior art;

fig. 2 shows a schematic view of an embodiment of a ground source heat exchanger arrangement according to the present invention;

fig. 3 shows a schematic view of another embodiment of a ground source heat exchanger arrangement according to the present invention;

fig. 4 shows a schematic view of yet another embodiment of a ground source heat exchanger arrangement according to the present invention;

fig. 5 shows a schematic view of yet another embodiment of a ground source heat exchanger arrangement according to the present invention;

fig. 6 shows a schematic view of a further embodiment of a ground source heat exchanger arrangement according to the present invention;

fig. 7 shows a schematic view of an embodiment of a ground source heat exchanger according to the present invention;

fig. 8 shows a schematic and detailed view of a ground source heat exchanger according to the present invention; and

fig. 9 shows a schematic view of an embodiment of the ground source heat exchanger arrangement according to the present invention.

Detailed Description

Figure 1 shows a conventional prior art geothermal heat exchanger and geothermal heat apparatus. The geothermal heat means comprises a ground hole 2 or borehole provided to the ground and extending downwardly into the ground from the ground surface 1. The earth hole 2 is formed by drilling. In the context of the present application, the depth of the earth's bore 2 may be at least 200 meters, or at least 300 meters, or between 300 meters and 3000 meters, or between 500 meters and 2500 meters.

The earth bore may extend to a depth below the ground water level in the earth, i.e. through the ground water level. Alternatively, the earth boring may extend to a depth above the water table in the earth.

It is to be noted that in the drawings, similar structural portions and structures are denoted by the same reference numerals, and description of the similar structural portions and structures is not repeated with respect to each drawing.

Furthermore, in the present application, the ground hole 2 may be any type of hole extending into the ground, and the ground hole 2 may be a vertical hole, a straight vertical hole or another straight hole extending into the ground at an angle to the ground or vertical direction. Additionally, the ground hole 2 may have one or more bends, and the direction of the ground hole may be changed toward the lower end or bottom of the ground hole one or more times along the length of the ground. Additionally, it should be noted that the shape or form of the standpipe and the drain pipe may preferably, at least substantially, conform to the shape or form of the earth's bore so as to provide for proper installation of the standpipe and the drain pipe into the earth's bore. Preferably, the ground hole extends to a depth as described above, but the ground hole may have one or more bends along its length, or the ground hole may be straight.

The earth material at the end (power end)4 of the earth hole is typically rock material.

There is a geothermal heat exchanger arranged in connection with the ground hole 2. The geothermal heat exchanger comprises a tube arrangement in which a primary working fluid circulates. The pipe arrangement typically comprises a closed loop pipe arranged to provide a closed circulation of the primary working fluid. The primary working fluid is typically a liquid such as water or a methanol or ethanol based working fluid. The pipe arrangement comprises a riser pipe 10 and a separate drainage pipe 20 arranged into the ground opening 2 such that the riser pipe 10 and the separate drainage pipe 20 extend from the ground towards the bottom 4 of the ground opening 2. The standpipe and the drain pipe are connected to each other with a connecting pipe portion 18 or a bend such that the standpipe and the drain pipe are in fluid communication with each other at the lower ends of the standpipe 10 and the drain pipe 20 to circulate primary working fluid between the standpipe 10 and the drain pipe 20 in the ground bore 2. As shown in fig. 1, the standpipe 10 and the drain pipe 20 form a U-shaped pipe structure. There may be one or more U-shaped tube structures or one or more risers 10 and drains 20 arranged into the same or different ground holes 2.

The geothermal heat exchanger further comprises a first pump 8 arranged to the tube means 10, 20 for circulating the primary working fluid in the tube means. The first pump 8 may be any type of known pump capable of circulating a primary working fluid.

The geothermal heat exchanger is also connected to a heat pump 30, in which heat exchange is carried out between a primary working fluid and a secondary working fluid, in the heat pump 30. In the heat pump 30, a primary working fluid flows in a primary circuit 32, and a secondary working fluid flows in a secondary circuit 34, and heat exchange is performed between the primary circuit 32 and the secondary circuit 34. The heat pump 30 may be any type of heat pump known in the art.

In fig. 1, a geothermal heat exchanger and heat pump 30 is arranged in connection with a building 50. The geothermal heat exchanger is used to heat or cool ventilation air of the building and, as a result, the ventilation air forms the secondary working fluid that is supplied to the heat pump 30. The primary working fluid is pumped as a cold primary stream 12 down the standpipe 10 towards the bottom end 4 of the earth bore 2. The temperature of the earth increases in the depth direction and towards the bottom end 4 of the earth hole 2. Accordingly, the primary working fluid extracts thermal energy H from the ground in the ground hole 2 and flows as a heated primary flow 22 up the separate drainage pipe 20 towards the ground 1. The heated primary stream 22 enters the heat pump 30 and releases thermal energy to the cold secondary stream 54 from the building 50. As a result, the temperature of the primary working fluid is reduced and the primary working fluid exits the heat pump 30 as a cold primary stream 12 for a new cycle. Similarly, the temperature of the secondary working fluid increases in the heat pump 30, and the secondary working fluid exits the heat pump as a heated secondary stream 52.

The flow and circulation of the primary and secondary flows may be changed from a heating mode, as described above, to a cooling mode in which the primary and secondary flows and heat transfer are reversed to cool the ventilation air of the building 50.

Fig. 2 shows an embodiment of the invention. In the present invention, the geothermal heat exchanger is arranged to inject thermal energy into the ground around the ground hole 2, in particular at the lower end 4 of the ground hole 2. The structure of the geothermal heat device and geothermal heat exchanger corresponds to the embodiment of fig. 1.

Accordingly, the hot secondary flow 52 is arranged to release thermal energy to the primary working fluid in the heat pump 30 such that the cold secondary flow 54 exits the heat pump 30 and the temperature of the secondary working fluid is reduced in the heat pump 30. The first pump 8 is arranged to circulate the primary working fluid as a heated primary flow 22 in a direction down the vertical pump 10 and as a cold primary flow in a direction up the drain pipe 20 as the primary working fluid releases thermal energy C from the heated primary flow to ground.

As shown, a heat pump or heat exchange connection is provided to or with the pipe arrangement outside the ground hole 2. The pipe arrangement may provide a closed circulation pipe for the primary working fluid and there is thus a connection pipe outside the ground opening 2 connecting the riser pipe 10 and the drainage pipe 20 to provide a closed circulation pipe.

The heat pump 30 may also be any other heat exchange connection such as a secondary heat exchanger. Thermal connection 30 provides heat exchange with the primary and secondary working fluids. Additionally, it should be noted that there may be more than one heat exchange connection provided in connection with the tube arrangement.

In one embodiment, the heat exchange connection 30 may be a heat source connection to release thermal energy into the primary working fluid and further into the ground.

According to the present invention, the standpipe 10 is provided with a first thermal shield 25 surrounding the standpipe 10 along at least a portion of the length of the standpipe 10. A first insulation 25 extends from the ground 1 down the riser 10 towards the bottom end 4 of the ground opening 2. The first insulation reduces heat transfer from the heated primary flow 22 of the primary working fluid along the riser pipe 10 to the ground surrounding the ground opening 2 and to the drain pipe 20 and the cold primary flow 12 in the drain pipe 20.

It should be noted that the first insulation 25 may also extend from above the ground 1, from the upper end 7 of the riser 10 or from the heat pump 30 towards the lower end 4 of the ground opening 2.

Standpipe 10 can include a layer of insulating material on the outer surface of standpipe 10 or on the inner surface of standpipe 10. The layer of insulating material is arranged to form a first thermal shield 25. The layer of spacer material may be formed of any known spacer material and the invention is not limited to any particular spacer material.

Additionally, it should be noted that the heat pump 30 may be any known type of heat pump or any type of heat exchange connection in which the primary working fluid may receive thermal energy outside the ground hole 2 and to which a geothermal heat exchanger or a tube arrangement of a geothermal heat exchanger may be connected.

In the embodiment of fig. 2, the riser pipe 10 and the drainage pipe 20 are arranged at a distance from each other and are connected to each other at the lower ends of the riser pipe 10 and the drainage pipe 20 with a connecting pipe portion 18 or a bend. That is, the standpipe 10 and the drain pipe 20 form a U-shaped pipe structure. It should be noted, however, that the present invention is not limited to any particular tube configuration for the standpipe 10 and drain tube 20, or any number of standpipe 10 and drain tubes 20.

In the embodiment of FIG. 2, the first insulation extends along the standpipe 10 to a distance from the lower end of the standpipe 10 or the connecting pipe portion 18 or bend.

The insulation 25 together with the heated primary flow 22 provided into the riser pipe 10 by the first pump 8 reduces or minimizes the heat transfer from the heated primary flow 22 in the riser pipe 10 so that the primary working fluid can be conveyed to the lower end of the first pipe 10 and the lower end 4 of the ground bore 2 in heated form or at a high temperature. Accordingly, at the lower end of the earth bore 2, the primary working fluid releases thermal energy C at high temperature to the earth around the earth bore 2 and thus injects the thermal energy into the earth for later use.

The first pump 8 may be a reversible pump arranged to pump the primary working fluid in a direction down the standpipe 10 and up the drain pipe 20, or alternatively, in a direction down the drain pipe 20 and up the standpipe 10. The first is an injection mode in which thermal energy is injected into the ground, and the second is an inversion mode, i.e., an extraction mode in which the injected thermal energy is extracted from the ground. The geothermal heat exchanger or geothermal heat device may further comprise a control unit 60, which control unit 60 is connected to the first pump 8 with a pump connection 61 and is arranged to control the direction of operation of the reversible first pump 8 between the injection mode and the extraction mode.

The control unit 60 may also be connected to the heat exchange connection 30 with an information connection 62 and arranged to operate the first pump 8 in response to an operating condition of the heat exchange connection 30, for example the temperature of the primary fluid and/or the secondary fluid in the heat exchange connection 30.

Fig. 3 shows another embodiment, in which the riser pipes 11 are arranged inside a separate drainage pipe 21. In addition, the embodiment of fig. 3 corresponds to the embodiment of fig. 2. In this embodiment the riser pipe 11 and the drain pipe 21 are arranged nested within each other, or the riser pipe 11 and the drain pipe 21 may be arranged coaxially within each other, such that the riser pipe 11 is inside the drain pipe 21. The heated primary flow 22 flows down the standpipe 11 with the first insulation 25 and out of the standpipe 11 from the open lower end 17 of the standpipe 11 into a drain pipe 21 surrounding the standpipe 11. The primary working fluid releases thermal energy C to the ground at the lower end 13 of the drain pipe 21 or at the lower end 4 of the ground opening 2 and then flows up the drain pipe 21 as a cold primary flow 12. The first thermal shield 25 reduces or minimizes heat transfer between the standpipe 11 and the drain pipe 21 and between the hot stream 22 and the cold stream 12, respectively.

As shown in fig. 3, the insulation 25 extends to a distance from the lower end 17 of the standpipe 17.

In the embodiment of fig. 3, the drain pipe 21 is a pipe having a closed lower end 13 and extending inside the ground hole 2 to the lower end 4 of the ground hole in the vicinity of the drain pipe 21. Accordingly, the standpipe 11 is completely inside the drainage pipe 21 in the earth bore 2, and the primary working fluid is not in direct contact with the earth.

Fig. 4 shows an embodiment corresponding to the embodiment of fig. 3. In this embodiment, the first insulation 25 extends from the surface 1 to the lower end 17 of the riser 11. Thus, the first thermal insulation 25 may extend along the entire length of the riser pipe 11 at least inside the ground opening 2 or the drainage pipe 21. The first thermal shield 25 may also extend along the entire length of the standpipe 11.

In this embodiment, the standpipe 11 can be an evacuated tube that includes a vacuum layer surrounding the flow passage of the standpipe 11. Thus, the vacuum layer is arranged to form a first thermal shield 25. The standpipe may also be provided with any other insulating material.

In this embodiment, the first insulation extends along the standpipe 11 to the lower end 17 of the standpipe 11.

The geothermal heat exchanger of fig. 4 comprises a second pump 9, which second pump 9 is arranged to pump the primary working fluid in a direction down the drain 21 and up the riser 11 when the geothermal heat exchanger and the geothermal heat device are in heat extraction mode. Accordingly, the first pump 8 is arranged to operate in a hot injection mode and the second pump 9 is arranged to operate in a hot extraction mode.

The control unit 60 may be connected to the first pump 8 and the second pump 9 and arranged to control the operation of the first pump 8 and the second pump 9 to selectively set the circulation direction of the primary working fluid to the heat injection mode or the heat extraction mode.

In fig. 4, there is no separate drain 21, but the holes 2 are arranged to form a drain 21.

Fig. 5 shows a modification of the embodiment of fig. 4. In this embodiment, the standpipe 11 is arranged inside the drain pipe 21 in the ground opening 2. A separate drainage pipe 21 extends from the ground 1 along the penetration distance N into the ground hole 2 and to a free distance P from the lower end 4 of the ground hole 2, so that the ground hole 2 forms a drainage pipe along the free distance P from the lower end of the ground hole 2.

Additionally, the riser pipe 11 extends out from the lower end 13 of the separate drain pipe 21 towards the lower end 4 of the ground hole 2 for an extension M. Thus, the standpipe 11 extends to a free distance P. Thus, in this embodiment, the ground hole 2 forms at least a part of the drain pipe. The ground hole 2 forms a drainage pipe along a free distance P from the lower end 4 of the ground hole 2 or between the lower end 4 of the ground hole 2 and the lower end 13 of a separate drainage pipe 21.

The first insulation 25 extends to the lower end 17 of the standpipe 11. However, the first insulation 25 may also extend only to the lower end 13 of the separate drain pipe 21, or then between the lower end 13 of the drain pipe 21 and the lower end 17 of the riser pipe 11.

Fig. 6 shows an embodiment wherein also the drain pipe 21 is provided with a second insulation 15 surrounding the drain pipe 21 along at least a part of the length of the drain pipe 21. The second thermal shield 15 may be provided in a similar manner to the first thermal shield 25. Accordingly, everything described with respect to the first thermal shield 25 is equally applicable to the second thermal shield 15. The second insulation 15 may be provided on the inner surface or the outer surface of the drain pipe 21. The second insulation 15 may extend along the drain pipe 21 to the lower end 13 of the drain pipe 21 or to a distance from the lower end 13. Thus, the primary working fluid may release thermal energy to the ground only at or near the lower end 4 of the ground bore 2, and the heat exchange between the cold primary flow 12 and the ground and the heated primary flow 22 is reduced. This may prevent the cold primary flow 12 from heating up in the upper discharge pipe 21 if at the upper part of the ground hole 2 the ground is at a higher temperature than the cold primary flow.

In the embodiment of fig. 2-6, the thermal conductivity of the first thermal shield 25 is already uniform in the direction along the stack 10, 11. Fig. 7 shows an embodiment wherein the thermal conductivity of the first thermal shield 25 decreases in a direction towards the lower end 17 of the standpipe 11. In this embodiment, the thickness of the first insulation 25 is arranged to decrease in a direction towards the lower end 17 of the standpipe 11, so that the thermal conductivity of the first insulation 25 decreases in a direction towards the lower end 17 of the standpipe 11. This enables the heated primary flow 22 to gradually increase the heat transfer to the cold primary flow 12 and the ground as it flows towards the lower end 17 of the riser 11 and the lower end 4 of the ground bore 2. The ground opening 2 forms at least a part of a drain pipe 21.

Fig. 8 schematically shows possible dimensions of the first thermal shield 25. The standpipe 11 has an upper end 7 and a lower end 17. The drain tube 21 has an upper end 27 and a lower end 13. The ground hole 2 extends from the ground 1 to a lower end 4 of the ground hole 2.

In one embodiment, as indicated by I in FIG. 8, the first thermal shield 25 can extend from the upper end 7 of the standpipe 11 along at least 50% of the length L of the standpipe 11 or at least 2/3 of the length L of the standpipe 11 toward the lower end 17 of the standpipe 11.

In another embodiment, the first thermal shield 25 can extend up the standpipe 11 from a predetermined distance O from the lower end 17 of the standpipe 11. The predetermined distance O from the lower end 17 of the standpipe 11 can be at least 10% of the length L of the standpipe 11 or at least 20% of the length L of the standpipe 11.

In yet another alternative embodiment, as indicated by J in fig. 8, the first thermal insulation 25 extends from the ground 1 along the riser pipe 11 towards the lower end 4 of the ground hole 2 or the lower end 13 of the drain pipe 21 and to at least 50% of the depth D of the ground hole 2 or at least 2/3 of the depth D of the ground hole 2.

Further alternatively, the first thermal shield 25 may extend up the standpipe 11 from a predetermined distance E from the lower end 4 of the ground hole 2 or the lower end 13 of the drain pipe 21. The predetermined distance E from the lower end 4 of the ground hole 2 or from the lower end 13 of the drain pipe 21 may be at least 10% of the depth D of the ground hole 2, or at least 20% of the depth D of the ground hole 2 or the length of the drain pipe 21.

Fig. 9 schematically illustrates the operation of the control unit 60 for operating the geothermal heat device. The geothermal heat device may include one or more temperature sensors 71 to measure the temperature in, for example, the interior of the building 50, the ambient atmosphere surrounding the building 50, the ventilation system of the building 50, or any other external location. The at least one temperature sensor 71 may be connected to the control unit 60, and the control unit 60 may be arranged to operate the first pump 8, or to operate the first pump 8 and the second pump 9, in response to a temperature input from the at least one temperature sensor 71.

Alternatively or additionally, the geothermal heat device may comprise one or more sensors 75, 77 arranged to the riser pipe 11 and/or the drain pipe 21. These sensors may be temperature sensors, flow sensors or some other type of sensor that measures the heated primary stream 22 and the cold primary stream 12. One or more sensors 75, 77 may be connected to the control unit 60, and the control unit 60 may be arranged to operate the first pump 8, or to operate the first and second pumps 8, 9, in response to measurement inputs from the one or more sensors 75, 77 in the standpipe 11 and/or the drain pipe 21.

The geothermal heating means may also comprise a timer 73 or a manually operated device connected to the control unit 60. The control unit 60 may be arranged to operate the first pump 8, or to operate the first pump 8 and/or the second pump 9, in response to a timer input from the timer 73 or a manual operation input from a manual operation device.

The control unit 60 may also be connected to an external data server 102 with a data transfer connection 100, such that the control unit 60 may be arranged to operate the first pump 8, or to operate the first pump 8 and/or the second pump 9, in response to data input from the external data server 102. The data transfer connection 100 may be any known type of wireless or wired data transfer connection, such as an internet connection, a local area network, a mobile communication network, etc. The external server 102 or external database may be any suitable server or database from which the control unit may obtain operational data tables controlling the operation of the first pump 8 or controlling the operation of the first pump 8 and the second pump 9.

In the embodiment of fig. 2 to 9, the heat exchange connection 30 preferably comprises a heat pump 30, the heat pump 30 being connected to the tube arrangement 10, 11, 20, 21 and being arranged to provide the heat exchange connection 30 for secondary heat exchange with the primary working fluid. The heat pump 30 may be arranged to release thermal energy to the primary working fluid to heat the primary working fluid, and the first pump 8 may be arranged to circulate the heated primary working fluid in the riser pipe 10, 11 in a direction towards the lower end 4 of the earth bore 2. This allows thermal energy to be transported to the lower end 4 of the earth bore 2 in the isolated risers 10, 11 and injected into the ground at the lower end 4 of the earth bore 2. Thus, the heat pump 30 is operated in a cooling mode and the geothermal heat exchanger is operated in an injection mode. The heat pump 30 may also be arranged to extract thermal energy from the primary working fluid to cool the primary working fluid, and the first pump 8 is arranged to circulate the primary working fluid in a direction from the lower end 4 of the earth bore 2 up the risers 10, 11. Thus, the heat pump 30 is operated in the heating mode and the geothermal heat exchanger is operated in the extraction mode.

The heat pump 30 may also be replaced by a heat exchanger. However, it is difficult to control the operating temperature in the heat injection mode and the heat extraction mode.

The geothermal heat exchanger and the geothermal heat device of the present invention enable the utilization of an efficient method for injecting heat energy into the ground and also utilize the injected heat energy for later use.

Accordingly, the method includes circulating a primary working fluid in a geothermal heat exchanger and providing heat exchange between a secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger such that the primary working fluid receives thermal energy from the secondary working fluid and the temperature of the primary working fluid increases. Thus, the geothermal heat device is operated in an injection mode in which the primary working fluid receives heat energy from the secondary working fluid in heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger. In the injection mode, the primary working fluid is also circulated in the risers 10, 11 in a downward direction and in the drainage pipes 20, 21 in an upward direction for transporting thermal energy, i.e. the primary working fluid or the heated primary flow 22 of high temperature, to the lower end 4 of the ground bore 4 and for releasing thermal energy from the primary working fluid to the ground at the lower end of the ground bore 2. Thus, heat energy is injected into the ground at the lower end 4 of the ground hole 2.

The method may further include operating the geothermal heat device in an extraction mode in which the primary working fluid releases heat energy to the secondary working fluid in heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger. In the extraction mode, the primary working fluid may be circulated in the drainage pipes 20, 21 in a downward direction and in the risers 10, 11 in an upward direction to transport thermal energy, i.e. the primary working fluid or the heated primary stream at high temperature, from the earth hole 2 and to release thermal energy from the primary working fluid to the secondary working fluid in heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger.

Providing heat exchange between the secondary working fluid and the primary working fluid circulating in the geothermal heat exchanger may include utilizing any type of heat source or additional heat source to provide thermal energy to the secondary working fluid. The additional heat source may be such that it is not connected to the method and apparatus during an extraction mode in which thermal energy is extracted from the earth hole 2. Accordingly, the method may include utilizing waste heat of a ventilation system of the building 50, thermal energy of an industrial plant, power generation plant, or manufacturing plant, or excess thermal energy of a data server facility or municipal heat source as a source for heating the secondary working fluid. Alternatively, the method may comprise generating thermal energy by using wind, hydraulic or solar power to heat the secondary working fluid.

The method may further comprise providing heat exchange in the heat pump 30 between a secondary working fluid and a primary working fluid circulating in a geothermal heat exchanger. Thus, the method includes operating the heat pump in a cooling mode in which the primary working fluid receives thermal energy from the secondary working fluid in the heat pump 30 and operating the geothermal heat exchanger in an injection mode. Alternatively, the method may include operating the heat pump in a heating mode in which the secondary working fluid receives thermal energy from the primary working fluid in the heat pump 30 and operating the geothermal heat exchanger in an extraction mode.

The method may further include operating the heat pump in a cooling mode in which the primary working fluid receives thermal energy from the secondary working fluid in the heat pump 30 and operating the geothermal heat exchanger in an injection mode in which the secondary working fluid receives thermal energy from the primary working fluid in the heat pump 30, and operating the heat pump in a heating mode in which the secondary working fluid receives thermal energy from the geothermal heat exchanger in the extraction mode.

The invention has been described above with reference to the examples shown in the drawings. The invention is, however, by no means limited to the above examples, but may be varied within the scope of the claims.