Groundwater enhanced geothermal heat pump

Patent metadata

Field	Value
Publication number	US-2022018577-A1
Application number	US-201917299363-A
Country	US
Kind code	A1
Filing date	Dec 4, 2019
Priority date	Dec 4, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

A geothermal heat pump system includes a main heat exchanger, a borehole that penetrates an aquifer, and a ground loop. The main heat exchanger is configured to exchange heat between a ground loop flow and a heat distribution system. The ground loop includes a first and second groundwater heat exchangers, an input pipe and an output pipe. The groundwater heat exchangers are respectively contained in first and second zones within the borehole and are exposed to a groundwater flow within the aquifer. The input pipe is configured to deliver the ground loop flow from the main heat exchanger to the groundwater heat exchangers. The output pipe is configured to deliver the ground loop flow from the groundwater heat exchangers to the main heat exchanger. Heat exchange occurs between the ground loop flow within the groundwater heat exchangers and the groundwater flow.

First claim

1 . A geothermal heat pump system comprising:
a main heat exchanger configured to exchange heat between a ground loop flow and a heat distribution system; a borehole that penetrates an aquifer; and a ground loop comprising:
a first groundwater heat exchanger contained within a first zone of the borehole and exposed to a groundwater flow within the aquifer;
a second groundwater heat exchanger contained within a second zone of the borehole and exposed to the groundwater flow, wherein the second zone is displaced from the first zone;
an input pipe configured to deliver the ground loop flow from the main heat exchanger to the first and second groundwater heat exchangers; and
an output pipe configured to deliver the ground loop flow from the first and second groundwater heat exchangers to the main heat exchanger;
wherein heat exchange occurs between the ground loop flow within the first and second groundwater heat exchangers and the groundwater flow.

2 . The system of claim 1 , wherein the borehole comprises:
a sealed wall section that blocks the groundwater flow into the borehole; and a permeable wall section through which the groundwater flow travels into the borehole.

3 . The system of claim 2 , wherein the permeable wall section includes a screen.

4 . The system of claim 1 , wherein:
the groundwater flow travels from a region of high hydraulic head to a region of low hydraulic head; and the first and second groundwater heat exchangers are positioned in the borehole between the region of high hydraulic head and the region of low hydraulic head.

5 . The system of claim 1 , wherein the groundwater flow travels horizontally across the borehole and the first and second groundwater heat exchangers.

6 . The system of claim 1 , further comprising packers configured to support the first and second groundwater heat exchangers within the borehole.

7 . The system of claim 1 , further comprising at least one packer in the borehole that divides a lower zone of the borehole containing the first groundwater heat exchanger from an upper zone of the borehole, and blocks water from flowing between the lower and upper zones.

8 . The system of claim 1 , further comprising a flow generator configured to circulate the groundwater flow over at least one of the first and second groundwater heat exchangers.

9 . The system of claim 8 , wherein the flow generator comprises a pump.

10 . (canceled)

11 . (canceled)

12 . The system of claim 1 , wherein the first groundwater heat exchanger comprises:
an input manifold connected to the input pipe and including a plurality of input ports; an output manifold connected to the output pipe and including a plurality of output ports; and a plurality of heat exchange tubes each extending into the groundwater flow and including an input end coupled to one of the input ports and an output end coupled to one of the output ports, wherein:
the input manifold distributes the ground loop flow from the input pipe to the plurality of heat exchange tubes through the input ports; and
the output manifold returns the ground loop flow from the plurality of heat exchange tubes to the output pipe through the output ports.

13 . The system of claim 12 , wherein the input and output manifolds are supported by a manifold body.

14 . The system of claim 12 , wherein the input and output manifolds are displaced from each other along an axis of the borehole.

15 . The system of claim 12 , wherein the plurality of heat exchange tubes each have a non-circular profile.

16 . A geothermal heat pump system comprising:
at least one main heat exchanger configured to exchange heat between a ground loop flow and a heat distribution system; a plurality of boreholes, each borehole penetrating an aquifer; each borehole containing one of a plurality of ground loops, each ground loop comprising:
a groundwater heat exchanger exposed to a groundwater flow within the aquifer;
an input pipe configured to deliver a portion of the ground loop flow from the main heat exchanger to the groundwater heat exchanger; and
an output pipe configured to deliver the portion of the ground loop flow from the groundwater heat exchanger to the main heat exchanger,
wherein:
heat exchange occurs between the portion of the ground loop flow within the groundwater heat exchanger and the groundwater flow;
each borehole includes an open surface end at a ground surface and an underground closed distal end; and
the distal ends of the boreholes are displaced from each other a greater distance than the surface ends are displaced from each other.

17 . (canceled)

18 . (canceled)

19 . The system of claim 16 , wherein each groundwater heat exchanger comprises:
an input manifold connected to the input pipe and including a plurality of input ports; an output manifold connected to the output pipe and including a plurality of output ports; and a plurality of heat exchange tubes each extending into the groundwater flow and including an input end coupled to one of the input ports and an output end coupled to one of the output ports; wherein:
the input manifold distributes the portion of the ground loop flow from the input pipe to the plurality of heat exchange tubes through the input ports; and
the output manifold returns the portion of the ground loop flow from the plurality of heat exchange tubes to the output pipe through the output ports.

20 . (canceled)

21 . The geothermal heat pump system of claim 1 , wherein:
the first and second zones are separated a packers; the groundwater flow includes a first groundwater flow through the first zone, and a second groundwater flow through the second zone that is isolated from the first groundwater flow; heat exchange occurs between the first groundwater heat exchanger and the first groundwater flow; and heat exchange occurs between the second groundwater heat exchanger and the second groundwater flow.

22 . A groundwater heat exchanger configured for use within a borehole comprising:
an input manifold including a plurality of input ports; an output manifold including a plurality of output ports; and a plurality of exposed heat exchange tubes each including an input end coupled to one of the input ports and an output end coupled to one of the output ports, wherein:
the input manifold is configured receive a ground loop flow and distribute the ground loop flow to the plurality of heat exchange tubes through the input ports; and
the output manifold is configured to discharge the ground loop flow received through the output ports from the plurality of heat exchange tubes to the main heat exchanger.

23 . The groundwater heat exchanger of claim 22 , wherein the input and output manifolds are supported by a manifold body.

24 . The groundwater heat exchanger of claim 22 , wherein the input and output manifolds are displaced from each other along an axis of the borehole.

25 . The groundwater heat exchanger of claim 22 , wherein the plurality of heat exchange tubes each have a non-circular profile.

Assignees

• Univ Minnesota

Inventors

• Randolph Jimmy Bryan
• Alexander Scott
• Saar Martin

Classifications

• Y02B10/40

  Geothermal heat-pumps · CPC title

• F24T10/30

  using underground reservoirs for accumulating working fluids or intermediate fluids · CPC title

• F24T10/15 Primary

  using bent tubes; using tubes assembled with connectors or with return headers · CPC title

• F24T2010/50

  Component parts, details or accessories · CPC title

• Y02E10/10

  Geothermal energy · CPC title