EP4479691A1

EP4479691A1 - Groundwater heat exchange system

Info

Publication number: EP4479691A1
Application number: EP23771453.0A
Authority: EP
Inventors: Ryan MARTIN-WAGAR; Jeffrey Seewald
Original assignee: Darcy Solutions Inc
Current assignee: Darcy Solutions Inc
Priority date: 2022-03-18
Filing date: 2023-03-17
Publication date: 2024-12-25
Also published as: WO2023177871A1

Abstract

A groundwater heat exchange system (100) for regulating a temperature of a loop fluid flow (112) pumped through a closed loop fluid pathway (104) for use by a heat pump (118) includes one or more groundwater heat exchange units (101) and a controller (150). Each groundwater heat exchange unit includes a heat exchanger (102) and at least one groundwater pump (136). The heat exchanger (102) is submersed in groundwater (110) within a borehole (106) and is configured to facilitate heat exchange between the groundwater and the loop fluid flow. Each groundwater pump has a plurality of non-zero flow rate settings corresponding to different non-zero flow rates at which the groundwater pump drives a flow of the groundwater (138) through the heat exchanger. The controller is configured to adjust the flow rate settings of the at least one groundwater pump based on a heat exchange demand input.

Description

GROUNDWATER HEAT EXCHANGE SYSTEM

FIELD

[0001] Embodiments of the present disclosure generally relate to the regulation of a temperature of a loop fluid flow for use by a heat pump and, more specifically, to a groundwater heat exchange system configured to regulate the temperature of the loop fluid flow through heat exchange with groundwater.

BACKGROUND

[0002] Heating and cooling systems generally move thermal energy from one location to another, such as moving thermal energy from a heat source to a heat sink (for example, a region of higher temperature to a region of lower temperature), or from a heat sink to a heat source (for example, a region of lower temperature to a region of higher temperature). Some heating and cooling systems utilize a heat pump. Heat pumps perform a refrigeration cycle using a circulating refrigerant to move heat through evaporation (heat absorption) and condensation (heat rejection) phases. The evaporation and condensation phases of the refrigerant typically take place in two different units called the evaporator and condenser, respectively. In a heat pump, the evaporator is switched to be a condenser and vice versa depending on whether cooling or heating is required.

[0003] Geothermal or ground source heat pumps use the earth as a heat source or heat sink. A heat exchanger is positioned underground to provide cooling by using the earth as a heat sink, or to provide heating by using the earth as a heat source. The ground loops of most traditional geothermal heat pump systems focus on heat exchange via conduction with subsurface rocks and sediments, and do not systematically take advantage of heat exchange with flowing or stationary groundwater.

[0004] U.S. Publication No. 2022/0018577 discloses a groundwater enhanced geothermal heat pump that utilizes a heat exchanger within a well, a geothermal borehole, etc., to exchange heat with the earth and/or groundwater. Highly efficient heat exchange is made possible by submerging the heat exchanger within the groundwater and circulating the groundwater through the heat exchanger. SUMMARY

[0005] Embodiments of the present disclosure are directed to groundwater heat exchange systems for regulating a temperature of a loop fluid flow pumped through a closed loop fluid pathway for use by a heat pump, and methods of controlling the system to relate the temperature of the loop fluid flow. In one embodiment, the system includes one or more groundwater heat exchange units and a controller. Each groundwater heat exchange unit includes a heat exchanger and at least one groundwater pump. The heat exchanger is submersed in groundwater within a borehole and is configured to facilitate heat exchange between the groundwater and the loop fluid flow. Each groundwater pump has a plurality of flow rate settings including a zero flow rate setting, in which the groundwater pump is in a deactivated state and does not drive a flow of the groundwater, and a plurality of non-zero flow rate settings corresponding to different non-zero flow rates at which the groundwater pump drives a flow of the groundwater through the heat exchanger. The controller is configured to adjust the flow rate settings of the at least one groundwater pump based on a heat exchange demand input, which indicates any one of a plurality of states of demand for heat exchange between the groundwater and the loop fluid flow including no demand for heat exchange and a demand for increased heat exchange.

[0006] In one embodiment, the at least one groundwater pump includes a first groundwater pump, and the controller adjusts the flow rate setting of the first groundwater pump to incrementally increase or decrease the flow rate of the corresponding flow of the groundwater based on the heat exchange demand input.

[0007] In another embodiment, the controller imposes a predetermined delay based on a delay setting in response to a change in the heat exchange demand input before adjusting the flow rate setting of the at least one groundwater pump.

[0008] According to another embodiment, the at least one groundwater pump includes a first groundwater pump configured to drive a first flow of the groundwater through the groundwater heat exchanger and a second groundwater pump configured to drive a second flow of the groundwater through the heat exchanger, and the controller adjusts the flow rate setting of the first groundwater pump and/or the flow rate setting of the second groundwater pump based on the heat exchange demand input.

[0009] The controller may adjust the flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in parallel based on the heat demand input. Alternatively, the controller may adjust the flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in a staggered manner based on the heat demand input.

[0010] In one embodiment, the controller transitions the first groundwater pump to one of the non-zero flow rate settings to increase a flow rate of the first flow to meet a demand for increased heat exchange indicated by the heat exchange demand input while the second groundwater pump is in the zero flow rate setting. When the first groundwater pump is operating at a maximum non-zero flow rate setting and the second groundwater pump is in the zero flow rate setting, the controller operates each of the first and second groundwater pumps in one of the non-zero flow rate settings in response to the heat exchange demand input indicating a demand for increased heat exchange.

[0011] In one embodiment, when the heat exchange demand input transitions from indicating no demand for heat exchange to indicating a demand for increased heat exchange, the controller initially transitions the first groundwater pump from the zero flow rate setting to one of the non-zero flow rate settings while the second groundwater pump remains in the zero flow rate setting. Subsequently, when the heat exchange demand input transitions from indicating no demand for heat exchange to indicating a demand for increased heat exchange, the controller initially transitions the second groundwater pump from the zero flow rate setting to one of the non-zero flow rate settings while the first groundwater pump remains in the zero flow rate setting.

[0012] According to another embodiment, the states of demand for heat exchange between the groundwater and the loop fluid flow indicated by the heat exchange demand input include a demand for decreased heat exchange.

[0013] In one example embodiment, when the first and second groundwater pumps are each operating in one of their non-zero flow rate settings, the controller adjusts the second groundwater pump to the zero flow rate setting when the heat exchange demand input indicates a demand for decreased heat exchange.

[0014] In another example embodiment, the first groundwater pump operates at a lower power than the second groundwater pump. When the heat exchange demand input transitions to indicating a demand for decreased heat exchange while the second groundwater pump is operating at a 50% maximum non-zero flow rate setting or less and the first groundwater pump is in the zero flow rate setting, the controller transitions the second groundwater pump to the zero flow rate setting and operates the first groundwater pump at its maximum nonzero flow rate setting.

[0015] In one embodiment, the first groundwater pump operates at a lower power than the second groundwater pump. When the first groundwater pump is operating at its maximum non-zero flow rate setting and the heat exchange demand input indicates a demand for increased heat exchange, the controller operates the first groundwater pump in the zero flow rate setting and operates the second groundwater pump in one of the non-zero flow rate settings.

[0016] In yet another embodiment, the controller periodically transitions each of the first and second groundwater pumps from the zero flow rate setting to one of the non-zero flow rate settings during periods when the heat exchange demand input indicates no demand for heat exchange.

[0017] According to one example embodiment, the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the plurality of heat exchangers, and a loop fluid return pipe, through which the loop fluid flow is returned to the plurality of heat exchangers. The system includes a temperature sensor having a temperature output that is indicative of a temperature of the loop fluid flow. The heat exchange demand input is based on a difference between a setpoint temperature, and the temperature of the loop fluid flow indicated by the temperature output. In one embodiment, the temperature output is indicative of the temperature of the loop fluid flow in the supply pipe.

[0018] In one example embodiment, the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the plurality of heat exchangers, and a loop fluid return pipe, through which the loop fluid flow is returned to the plurality of heat exchangers. The system includes a bypass pipe connecting the loop fluid supply pipe to the loop fluid return pipe and a bypass valve configured to regulate a flow of the loop fluid between the loop fluid supply and return pipes through the bypass pipe.

[0019] According to another embodiment, the one or more groundwater heat exchange units include a first groundwater heat exchange unit and a second groundwater heat exchange unit. The heat exchangers of the first and second groundwater heat exchange units are each positioned within the same borehole. [0020] In one embodiment, the one or more groundwater heat exchange units include a first groundwater heat exchange unit and a second groundwater heat exchange unit. The heat exchanger of the first groundwater heat exchange unit is positioned within a first borehole. The heat exchanger of the second groundwater heat exchange unit is positioned within a second borehole that is displaced from the first borehole.

[0021] In one example embodiment, the system includes valving and a flow rate sensor. The valving is configured to selectively circulate the loop fluid flow through one or both of the first and second groundwater heat exchange units. The flow rate sensor is configured to detect a flow rate of the loop fluid flow upstream of the valving. The controller is configured to compare the detected flow rate to a threshold flow rate. When the flow rate of the loop fluid flow is below the threshold flow rate, the controller actuates the valving to circulate the loop fluid flow through the first groundwater heat exchange unit and to block the loop fluid flow from being circulated through the second groundwater heat exchange unit. When the flow rate of the loop fluid flow is above the threshold flow rate, the controller actuates the valving to circulate the loop fluid flow through the first and second groundwater heat exchange units.

[0022] In one embodiment of the method of controlling a groundwater heat exchange system for regulating a temperature of a loop fluid flow pumped through a closed loop fluid pathway for use by a heat pump, the groundwater heat exchange system includes one or more groundwater heat exchange units and a controller. Each groundwater heat exchange unit includes a heat exchanger and at least one groundwater pump. The heat exchanger is submersed in groundwater within a borehole and is configured to facilitate heat exchange between the groundwater and the loop fluid flow. Each groundwater pump has a plurality of flow rate settings including a zero flow rate setting, in which the groundwater pump is in a deactivated state and does not drive a flow of the groundwater, and a plurality of non-zero flow rate settings corresponding to different non-zero flow rates at which the groundwater pump drives a flow of the groundwater through the heat exchanger. The controller is configured to adjust the flow rate settings of the at least one ground water pump based on a heat exchange demand input, which indicates any one of a plurality of states of demand for heat exchange between the groundwater and the loop fluid flow including no demand for heat exchange and a demand for increased heat exchange. The method includes steps of exchanging heat between the groundwater and the loop fluid flow using the heat exchanger, adjusting the flow rate setting of one or more of the at least one groundwater pump based on a heat exchange demand input using the controller, and repeating the exchanging and adjusting steps a limited number of times.

[0023] In one embodiment of the method, the at least one groundwater pump includes a first groundwater pump, and the adjusting step includes adjusting the flow rate setting of the first groundwater pump to incrementally increase or decrease the flow rate of the corresponding flow of the groundwater based on the heat exchange demand input.

[0024] According to another embodiment of the method, the adjusting step includes delaying adjusting the flow rate setting of the first groundwater pump for a predetermined delay time based on a delay setting in response to a change in the heat exchange demand input received in the receiving step.

[0025] In one example embodiment of the method, the at least one groundwater pump includes a first groundwater pump configured to drive a first flow of the groundwater through the groundwater heat exchanger and a second groundwater pump configured to drive a second flow of the groundwater through the heat exchanger. The adjusting step includes adjusting the flow rate setting of the first groundwater pump and/or the flow rate setting of the second groundwater pump based on the heat exchange demand input.

[0026] In yet another example of the method, the adjusting step includes adjusting the flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in parallel based on the heat demand input.

[0027] According to another embodiment of the method, the adjusting step includes adjusting the flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in a staggered manner based on the heat demand input.

[0028] In one embodiment of the method, when the heat exchange demand input indicates a demand for increased heat exchange, the first groundwater pump is operating in a non-zero flow rate setting that is less than a maximum non-zero flow rate setting and the second groundwater pump is in the zero flow rate setting, the adjusting step includes incrementally adjusting the first ground water pump to one of the non-zero flow rate settings to increase the flow rate of the first flow while the second groundwater pump remains in the zero flow rate setting. When the heat exchange demand input indicates a demand for increased heat exchange, the first groundwater pump is operating in the maximum non-zero flow rate setting and the second groundwater pump is in the zero flow rate setting, the adjusting step includes adjusting each of the first and second groundwater pumps to one of their non- zero flow rate settings.

[0029] In another embodiment of the method, in a series of the adjusting steps, the flow rate settings of the first and second groundwater pumps are adjusted on an alternative basis.

[0030] In one embodiment of the method, the states of demand for heat exchange between the groundwater and the loop fluid flow indicated by the heat exchange demand input include a demand for decreased heat exchange. When the first and second groundwater pumps are each operating in one of their non-zero flow rate settings and the heat exchange demand input indicates a demand for decreased heat exchange, the adjusting step includes operating the first groundwater pump in one of the non-zero flow rate settings and adjusting the flow rate setting of the second groundwater pump to the zero flow rate setting.

[0031] In one example embodiment of the method, the states of demand for heat exchange between the groundwater and the loop fluid flow indicated by the heat exchange demand input include a demand for decreased heat exchange, and the first groundwater pump operates at a lower power than the second groundwater pump. When the second groundwater pump is operating at 50% of its maximum non-zero flow rate setting or less, the first groundwater pump is in the zero flow rate setting and the heat exchange demand input transitions to indicating a demand for decreased heat exchange, the adjusting step includes adjusting the flow rate setting of the second groundwater pump to the zero flow rate setting and adjusting the flow rate setting of the first groundwater pump to its maximum non-zero flow rate setting.

[0032] According to another embodiment of the method, the first groundwater pump operates at a lower power than the second groundwater pump. When the first groundwater pump is operating at its maximum non-zero flow rate setting, the second groundwater pump is set to the zero flow rate setting, and the heat exchange demand input indicates a demand for increased heat exchange, the adjusting step includes adjusting the flow rate setting of the first groundwater pump to the zero flow rate setting and adjusting the flow rate setting of the second groundwater pump to one of the non-zero flow rate settings.

[0033] In yet another example embodiment of the method, the adjusting step includes periodically adjusting each of the first and second groundwater pumps from the zero flow rate setting to one of their non-zero flow rate settings during periods when the heat exchange demand input indicates no demand for heat exchange. [0034] In one embodiment of the method, the receiving step includes sensing a temperature of the loop fluid flow using a loop fluid temperature sensor, and determining the heat exchange demand input based on a comparison of the sensed temperature of the loop fluid to a setpoint temperature.

[0035] According to another embodiment of the method, the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the heat exchanger, and a loop fluid return pipe, through which the loop fluid flow is returned to the heat exchanger, and sensing the temperature of the loop fluid flow includes sensing the temperature of the loop fluid flow in the supply pipe.

[0036] According to one example embodiment of the method, the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the heat exchanger, and a loop fluid return pipe, through which the loop fluid flow is returned to the heat exchanger. The system includes a bypass pipe connecting the loop fluid supply pipe to the loop fluid return pipe and a bypass valve configured to regulate a flow of the loop fluid between the loop fluid supply and return pipes through the bypass pipe. The method includes adjusting the bypass valve based on the heat exchange demand input using the controller.

[0037] In yet another embodiment of the method, the system includes a plurality of the groundwater heat exchange units and the heat exchangers of the plurality of groundwater heat exchange units are each positioned within the same borehole. The exchanging step includes exchanging heat between the groundwater and the loop fluid flow using the heat exchangers of the plurality of groundwater heat exchange units.

[0038] In one embodiment of the method, the system includes a plurality of the groundwater heat exchange units including a first groundwater heat exchange unit and a second groundwater heat exchange unit. The heat exchanger of the first groundwater heat exchange unit is positioned within a first borehole, and the heat exchanger of the second groundwater heat exchange unit is positioned within a second borehole that is displaced from the first borehole.

[0039] According to another embodiment of the method, the system includes valving configured to selectively circulate the loop fluid flow through one or both of the first and second groundwater heat exchange units, and a flow rate sensor configured to detect a flow rate of the loop fluid flow upstream of the valving. The method includes detecting the flow rate of the loop fluid flow using the flow rate sensor, comparing the detected flow rate to a threshold flow rate using the controller, actuating the valving to circulate the loop fluid flow through the first groundwater heat exchange unit and to block the loop fluid flow from circulating through the second groundwater heat exchange unit using the controller when the flow rate of the loop fluid flow is below the threshold flow rate, and actuating the valving to circulate the loop fluid flow through the first and second groundwater heat exchange units using the controller when the flow rate of the loop fluid flow is above the threshold flow rate. [0040] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 is a simplified cross-sectional view of a groundwater heat exchange system, in accordance with embodiments of the present disclosure.

[0042] FIG. 2 is a simplified cross-sectional view of a portion of an embodiment of a groundwater heat exchange system having multiple heat exchange units, in accordance with embodiments of the present disclosure.

[0043] FIG. 3 is a simplified diagram of a groundwater heat exchange system having multiple ground water heat exchange units that are contained within separate boreholes, in accordance with embodiments of the present disclosure.

[0044] FIG. 4 is a simplified diagram of an example of the controller, in accordance with embodiments of the present disclosure.

[0045] FIG. 5 is a flowchart illustrating a method of controlling a groundwater heat exchange system to regulate a temperature of a loop fluid flow using one or more of the groundwater units, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0046] Embodiments of the present disclosure generally relate to the control of a geothermal heat pump system that utilizes groundwater heat exchangers that are configured for use in heating and cooling systems, such as a geothermal heat pump system, and may be configured and placed for use within wells or geothermal boreholes to exchange heat with the earth and/or groundwater. The interaction between the heat exchanger and groundwater enhances heat exchange, such as through convective and advective heat exchange.

[0047] Embodiments of the present disclosure are described more fully hereinafter with reference to the accompanying drawings. Elements that are identified using the same or similar reference characters refer to the same or similar elements. The various embodiments of the present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0048] FIG. 1 is a simplified cross-sectional view of a groundwater heat exchange system 100, in accordance with embodiments of the present disclosure. The system 100 includes at least one groundwater heat exchange unit 101, each including one or more groundwater heat exchangers 102. Each groundwater heat exchanger 102 is positioned within a vertical borehole or well 106 (hereinafter “borehole”) below the ground surface 108 that penetrates one or more aquifers or groundwater zones in which groundwater 110 is present. The borehole 106 may have a diameter of approximately 3-24 inches, such as 4, 6 or 8 inches, for example.

[0049] The groundwater heat exchangers 102 are each configured to exchange heat between the groundwater 110 in which it is submerged and a loop fluid flow 112 (e.g., water, refrigerant, etc.) that is circulated through a closed ground loop or loop fluid pathway 104 using one or more loop fluid pumps 114. In one example, the loop fluid pathway 104 includes pipes 116A and 116B that are Huidically coupled to heat exchange piping 117 of each heat exchanger 102 that is submerged within the groundwater 110. Accordingly, the heat exchange piping 117 may form a portion of the loop fluid pathway 104. The loop fluid flow 112 may be received from the pipe 116B at an input port of the heat exchange piping 117, travel through the heat exchange piping 117 and exchange heat with the groundwater 110 surrounding the piping 117, and be discharged through an output port to the pipe 116A. This heat exchange may involve cooling or heating the loop fluid flow 112. Examples of suitable groundwater heat exchangers 102 that may be used in the system 100 are disclosed in U.S. Publication No. 2022/0018577.

[0050] In one embodiment, the pipes 116 of the loop fluid pathway 104 and the piping 117 of each groundwater heat exchanger 102 form a closed loop of piping that does not receive groundwater or carry groundwater to the surface 108. Separate piping (not shown) may be used to capture and return subsurface groundwater 110 to the surface for use (e.g., consumption).

[0051] The pipes 116A and 116B that extend outside the groundwater heat exchangers 102 may be thermally insulated to isolate or promote heat exchange between the loop fluid flow 112 and the groundwater 110 only at the one or more groundwater heat exchangers 102. Thus, rather than providing heat exchange along nearly the entire length of the borehole 106, some embodiments of the system 100 provide substantially all heat exchange with the groundwater 110 at the one or more groundwater heat exchangers 102 within the borehole 106.

[0052] In some embodiments, each groundwater heat exchange unit 101 includes one or more submersible groundwater pumps 136, each of which is configured to drive a flow 138 of the groundwater 110 around the heat exchange piping 117 of the one or more heat exchangers 102 of the unit 101. The groundwater flow 138 enhances the heat exchange between the loop fluid flow 112 and the groundwater 110 through convection and advection at the heat exchange piping 117. As discussed in greater detail below, a flow rate of the groundwater flow 138 generated by the one or more pumps 136 may be controlled to adjust the rate of heat exchange between the groundwater 1 10 and the loop fluid flow 112 within each unit 101 .

[0053] The system 100 may include one or more temperature sensors 142 that are configured to detect a temperature of the loop fluid flow 112, as shown in FIG. 1. In one embodiment, the system 100 includes a temperature sensor 142 A configured to output a temperature signal that is indicative of a temperature of the loop fluid flow 112 in the pipe 116A, such as after the loop fluid flow 112 has passed through one or more of the heat exchange units 101, and/or a temperature sensor 142B that is configured to output a temperature signal that is indicative of the temperature of the loop fluid flow 112 in the pipe 116B, such as before the loop fluid flow 112 passes through the one or more heat exchange units 101.

[0054] The system 100 may also include one or more temperature sensors 144 that are configured to detect a temperature of the groundwater 110. For example, the system 100 may include a temperature sensor 144A that detects the temperature of the groundwater 110 or groundwater flow 138 at an input side before it passes through the heat exchanger 102 and, thus, prior to exchanging heat with the loop fluid flow 112, and/or a temperature sensor 144B that detects the temperature of the groundwater 110 or groundwater flow 138 at an output side after passing through the heat exchanger 102 and, thus, after exchanging heat with the loop fluid flow [0055] FIG. 2 is a simplified cross-sectional view of a portion of an embodiment of the system 100 having multiple heat exchange units 101, such as units 101A-C, contained within a borehole 106, in accordance with embodiments of the present disclosure. Some of the features of FIG. 1 located above the surface 108 are not shown to simplify the illustration. As discussed above, the groundwater heat exchange units 101 may include one or more groundwater heat exchangers 102, such as groundwater heat exchangers 102A and 102B of unit 101A, for example. Each of the groundwater heat exchangers 102 are configured to receive the loop fluid flow 112 and operate as discussed above. Thus, each of the units 101 may include one or more associated groundwater pumps 136, temperature sensors 144A and/or temperature sensors 144B, as indicated in FIG. 2.

[0056] One or more packers 146 may be used to seal off different sections of the borehole 106 from other sections and isolate each groundwater heat exchange unit 101 and its associated components within a section of the borehole 106 from the other units 101, as shown in FIG. 2. The packers 146 may be designed to allow power cables and other wires (e.g., sensor wires) to pass through to components of the system 100 within the borehole 106.

[0057] Heat exchange units 101 having multiple groundwater heat exchangers 102, such as unit 101 A in FIG. 2, may connect the heat exchange piping 117 (FIG. 1) of the groundwater heat exchangers 102 in series. For example, with reference to FIG. 2, the output port of the heat exchange piping of the heat exchanger 102 A of the unit 101 A may be connected to the input port of the heat exchange piping of the heat exchanger 102B to connect the exchangers 102 A and 102B in series. Thus, the loop fluid flow 112 delivered to the unit 101 A through the pipe 116B will travel through the heat exchanger 102A, then the heat exchanger 102B, from which it is discharged to the pipe 116A, or vice versa depending on the direction of the loop fluid flow 112.

[0058] In some embodiments, the fluid flow pathway 104 may connect the multiple heat exchange units 101 in series with each other. Thus, the loop fluid flow 112 from the pipe 116A may, for example, be connected to the input of the unit 101A (e.g., input to its heat exchangers 102), and the output of the unit 101A (e.g., output from its heat exchangers 102) may be connected to the input of the unit 101B, and so on to connect all of the units 101 to the loop fluid flow. Thus, the loop fluid flow 112 in the pipe 116B first travels through the heat exchangers 102 of the unit 101, then through the heat exchangers 102 of the unit 101B, then through the heat exchangers 102 of the unit 101C, and so on. The loop fluid flow 112 is then discharged to the pipe 116A from the last unit 101 in the series.

[0059] FIG. 3 is a simplified diagram of a groundwater heat exchange system 100 having multiple groundwater heat exchange units 101A-C that are respectively contained within distinct boreholes 106A-C, in accordance with embodiments of the present disclosure. While only a single heat exchange unit 101 is shown in each borehole 106, it is understood that multiple heat exchange units may be installed in each borehole 106 as discussed above with reference to FIG. 2. The system 100 may use one or more of the units 101A-C to provide a desired heat exchange between the loop fluid flow 112 and the groundwater 110 within the distinct boreholes 106A-C. It is understood that embodiments of the system 100 are not limited to the three boreholes 106A-C illustrated in FIG. 3, and may include the use of two or more boreholes 106 each having a corresponding heat exchange unit 101.

[0060] One alternative to connecting the heat exchange units 101 in series, is to connect them in parallel to the loop fluid flow 112 or loop fluid pathway 104. An example of such a parallel connection is illustrated in FIG. 3, where the inputs of the units 101 are each directly connected to the pipe 116A of the loop fluid pathway 104, and the outputs of the units 101 are each connected to the pipe 116B of the pathway 104. This arrangement allows the system 100 to utilize different aquifers or pools of groundwater 110, as compared to the single borehole 106 systems 100 shown in FIGS. 1 and 2. Heat exchange between the loop fluid flow or flows 112 and the groundwater 110 in each borehole 106 may be controlled through the selective activation of the units 101, as discussed below.

[0061] In some embodiments, the system 100 includes control and/or balancing valving 129 (FIGS. 1 and 3) for controlling the loop fluid flow 112 through the loop fluid pathway 104 and the one or more heat exchange units 101. The valving 129 may be comprised in a header 130 located at or near the surface 108. The valving 129 may be mechanically or electronically controlled to control heat exchange between the loop fluid flow 112 and the groundwater 110 at each unit 101 by controlling a flow rate of the loop fluid flow 112 through the units 101 as well as the connection of the loop fluid flow or flows 112 to the units 101.

[0062] When the one or more units 101 are connected in series with the loop fluid flow 112, as shown in FIG. 1, a valve 132 of the valving 129 may control the loop fluid flow through the fluid pathway, such as through the pipe 116A. [0063] To connect the units 101 in parallel with the loop fluid pathway 104, as shown in FIG. 3, the valving 129 may include, for example, a manifold and valves to either connect or disconnect each of the units 101 to the loop fluid flow 112. For example, the valving 129 may include valves 132A-C that respectively control the delivery of the loop fluid flow 112 to the units 101 A-C, as shown in FIG. 3.

[0064] In one embodiment, the valving 129 includes a bypass valve 134 that controls a flow of the loop fluid flow 112 through a bypass pipe 135 connecting the pipes 116A and 116B, as shown in FIGS. 1 and 3. The bypass valve 134 may be operated in response to the temperature of the loop fluid flow 112 detected by the temperature sensor 142A and/or the temperature sensor 142B, and used to regulate a flow the loop fluid between the pipes 116A and 116B to provide additional control of the loop fluid flow 112 and its temperature.

[0065] The system 100 may also include a flow rate sensor 140 that is configured to detect a flow rate of the loop fluid flow 112 prior to its distribution to the one or more heat exchange units 101, and produce a flow rate output that is indicative of the detected flow rate. As discussed below, the detected flow rate may be used to control the activation and deactivation of the heat exchange units 101 .

[0066] One example of a suitable flow rate sensor 140 is a differential pressure sensor 140 that is configured to detect a differential pressure between the supply and return pipes 116A and 116B, which may be used to determine the flow rate of the loop fluid flow 112. Other suitable flow rate sensors may also be used to determine the flow rate of the loop fluid flow 112.

[0067] The system 100 may be used in connection with a heat pump 118 to form a geothermal heat pump system, as illustrated in FIG. 1. The heat pump 118 may represent one or more systems that utilize the loop fluid flow 112 for a desired heat exchange operation. In the illustrated example, the pipe 116A of the closed loop fluid pathway operates as a supply pipe to supply the heat pump 118 with the loop fluid flow 112 from the one or more heat exchange units 101, and the pipe 116B operates as a return pipe to deliver the loop fluid flow 112 back to the one or more heat exchange units 101 to exchange heat with the groundwater 110.

[0068] The supplied loop fluid flow 112 may be received by a main heat exchanger 120 that is configured to exchange heat between the supplied loop fluid flow 112 and a fluid flow 122 (e.g., water, refrigerant, etc.), using any suitable technique. The loop fluid flow 122 output from the main heat exchanger 120 travels through a heat distribution system 124 to provide the desired heating or cooling, such as for a building, a water supply, etc., using conventional techniques. Alternatively, the heat pump 118 may operate without the main heat exchanger 120 and utilize the loop fluid flow 112 to directly heat or cool a desired medium.

[0069] The heat pump 118 may also include conventional heat pump components, such as a compressor 126, an expander or expansion valve 128, and/or other conventional components, as shown in FIG. 1, to perform a desired heat pump cycle. While the compressor 126 and the expansion valve 128 are illustrated as performing a heating cycle based on the direction of the fluid flow 122, it is understood that the direction of the fluid flow 122 may be reversed to perform a cooling cycle. Such heating and/or cooling operations will henceforth be generally referred to as heat exchange operations.

[0070] In some embodiments, the system 100 includes a controller 150 that is configured to perform one or more functions described herein, as indicated in FIG. 1. The controller 150 may take on any suitable form.

[0071] FIG. 4 is a simplified diagram of an example of the controller 150, in accordance with embodiments of the present disclosure. The controller 150 is configured to perform various functions of the system 100 to control the heat exchange between the loop fluid flow 1 12 and the groundwater 1 10 at each heat exchange unit 101. These functions may include, for example, controlling the one or more groundwater pumps 136, the loop fluid pump 114, the valving 129 and/or other components of the system 100, and processing of inputs 152, such as the signals from each temperature sensor 142, the signals from each temperature sensor 144, the signal from the flow rate sensor 140, and/or other inputs.

[0072] In one embodiment, the controller 150 represents one or more processors 154 that control components of the system 100 to perform one or more functions described herein in response to the execution of instructions stored in memory 156. The one or more processors 154 of the controller 150 may be components of one or more computer-based systems, and may include one or more control circuits, microprocessor-based engine control systems, and/or one or more programmable hardware components, such as a field programmable gate array (FPGA). The memory 156 represents local and/or remote memory or computer readable media. Such memory 156 comprises any suitable patent subject matter eligible computer readable media that do not include transitory waves or signals such as, for example, hard disks, CD-ROMs, optical storage devices, and/or magnetic storage devices. The controller 150 may include circuitry 158 for use by the one or more processors to receive input signals 152 (e.g., sensor signals, command signals, etc.), issue control signals 160 (e.g., valve control signals, pump control signals, etc.), and or communicate data 162 (e.g., sensor data, valve setting data, pump setting data, etc.), such as in response to the execution of the instructions stored in the memory 156.

[0073] In some embodiments, the controller 150 selectively controls flow rate settings of the one or more groundwater pumps of each unit 101 to control the flow rate of the groundwater flow 138 through the one or more heat exchangers 102 and the rate of heat exchange between the groundwater 110 and the loop fluid flow 112. The flow rate settings for the pumps 136 may be controlled through any suitable configuration, such as through the Variable Frequency Drive (VFD) for the pumps 136, for example. In some embodiments, the controller 150 performs these groundwater pump 136 control operations based on a heat exchange demand input, which may be determined by the controller 150 or provided to the controller 150 in the form of an input 152, such as a command from another source, such as a controller of the heat pump 118, for example.

[0074] The heat exchange demand input may selectively indicate any one of a plurality of states of demand for heat exchange between the groundwater 110 and the loop fluid flow 112. These states of demand may include a state of no demand for heat exchange, such as when the temperature of the loop fluid flow 112 supplied to the heat pump 118 satisfies its needs, and a state of demand for increased heat exchange between the groundwater 110 and the loop fluid flow 112, such as when the temperature of the loop fluid flow 112 supplied to the heat pump 118 does not satisfy its needs. In some embodiments, the heat exchange demand input may also indicate a state of demand for decreased heat exchange between the groundwater 110 and the loop fluid flow 112, such as when the temperature of the loop fluid flow 112 supplied to the heat pump 118 exceeds the needs of the heat pump 118 by a certain margin or threshold, which may be accessed from the memory 156.

[0075] In some embodiments, the heat exchange demand input is based on the temperature of the loop fluid flow 112 supplied to the heat pump 118 detected by the temperature sensor 142A and a setpoint temperature of the loop fluid flow 112, which may be received from the heat pump 118 or another source as an input 152, or accessed from the memory 156. The setpoint temperature indicates a desired temperature for the loop fluid flow 112 supplied to the heat pump 118. The heat exchange demand input indicates no demand for heat exchange when the temperature of the loop fluid flow 112 supplied to the heat pump 118 satisfies the demand indicated by the setpoint temperature, and the heat exchange demand input indicates a demand for increased heat exchange when the temperature of the loop fluid flow 112 supplied to the heat pump 118 does not satisfy the demand indicated by the setpoint temperature, such as when the temperature of the loop fluid flow 112 indicated by the sensor 142 A is either too high or too low depending on whether the heat pump 118 is performing a cooling or heating operation. In some embodiments, when the temperature of the loop fluid flow 112 supplied to the heat pump 118 exceedingly satisfies the demand indicated by the setpoint temperature by a predetermined number of degrees, the heat exchange demand input may indicate a demand for decreased heat exchange.

[0076] In some embodiments, the indications of a demand for increased or decreased heat exchange provided by the heat exchange demand input correspond to a degree to which the rate of heat exchange should be increased or decreased. This may be based on a difference between the temperature of the supplied loop fluid flow 112 and the setpoint temperature. For example, the greater the difference between the temperature of the supplied loop fluid flow 112 and the setpoint temperature, the greater the degree of change that is indicated by the heat exchange demand input. In some embodiments, different threshold temperature differences are used to indicate different incremental degrees of change that may be compared to the difference between the temperature of the supplied loop fluid flow 112 and the setpoint temperature to determine the degree of change to be indicated by the heat exchange demand input. Such threshold temperature differences may be stored in the memory 156 for use by the controller 150. Other techniques (e.g., formula) for determining a degree of change may also be used.

[0077] The heat exchange demand input or the degree of change indicated by the heat exchange demand input may also be based on a difference between the temperature of the supply loop fluid flow 112 detected by the temperature sensor 142A and the temperature of the return loop fluid flow 112 detected by the temperature sensor 142B, the groundwater temperature detected by the temperature sensor(s) 144A corresponding to one or more of the groundwater heat exchangers 102, and/or a difference between the groundwater temperatures detected by temperature sensor 144A and temperature sensor 144B of the one or more units 101. [0078] In some embodiments, the one or more groundwater pumps 136 used in connection with one of the groundwater heat exchangers 102 include two or more groundwater pumps 136, such as pumps 136A and 136B shown in FIG. 1. By operating the groundwater pumps 136A and 136B in different flow rate settings, such as through control signals 160 issued by the controller 150, a wide range of flow rates of the groundwater flow 138 may be produced and driven through the groundwater heat exchanger 102. This wide range of flow rates of the groundwater flow 138 may be used to control a corresponding wide range of heat exchange rates between the loop fluid flow 112 and the groundwater 110 at the heat exchanger 102 to satisfy a desired heat exchange demand indicated by the heat exchange demand input.

[0079] Multiple flow rates of the groundwater flow 138 may be generated by the multiple pumps 136 by operating the pumps 136 in a staggered manner, which involves adjusting the flow rate settings of one of the pumps 136 at a time, and/or in a parallel manner, which involves simultaneously adjusting the flow rate settings of the pumps 136, to establish a desired flow rate of the groundwater flow 138 and rate of heat exchange between the groundwater 110 and the loop fluid flow 112.

[0080] For example, the groundwater pumps 136A and 136B may each have a zero flow rate setting corresponding to a deactivated state, in which they do not drive a groundwater flow 138, and at least one non-zero flow rate setting (activated state), in which they drive the groundwater flow 138. If the pumps are identical (e.g., identical power) and each have a singular non-zero flow rate setting, in which they drive the groundwater flow 138 at the same flow rate, then this combination of pumps results in two different non-zero flow rates (e.g., high and low) of the groundwater flow 138 when they are operated in a staggered manner: a low flow rate corresponding to when one of the pumps 136A or 136B is operating in its non-zero flow rate setting while the other is in the deactivated state; and a high flow rate in which each of the pumps 136A and 136B are operating in their non-zero flow rate setting.

[0081] The number of flow rates that may be driven by the pumps 136A and 136B increases when each has a singular non-zero flow rate setting that produces a different flow rate of the groundwater flow 138. This may occur when, for example, one of the pumps 136, such as pump 136A, is a low power pump configured to generate a relatively low flow rate and one the other pumps, such as pump 136B, is a high power pump configured to generate a relatively high flow rate. In this case, the number of flow rates of the groundwater flow 138 that may be produced increases to three: a first flow rate corresponding to the operation of the pump 136A in its nonzero flow rate setting while the pump 136B is deactivated; a second flow rate corresponding to the operation of the pump 136B in its non-zero flow rate setting while the pump 136A is deactivated; and a third flow rate corresponding to the operation of both pumps 136A and 136B in their non-zero flow rate settings. [0082] The use of a relatively low power pump 136A and a relatively high power pump 136B allows the system 100 to maximize the power efficiency at which the system 100 satisfies the need indicated by the heat exchange demand input. That is, to conserve electrical energy consumption, the system 100 may utilize the relatively low power pump 136A until it is unable to meet the need indicated by the heat exchange demand input. The relatively high power pump 136B may then be used in place of, or in addition to, the relatively low power pump 136A only when necessary to meet the demand indicated by the heat exchange demand input.

[0083] In some embodiments, the pumps 136 have multiple non-zero flow rate settings ranging from a minimum non-zero flow rate setting (e.g., 5-25% of the maximum) to a maximum non-zero flow rate setting (100% maximum). This allows the pumps 136 to generate several non-zero flow rates of the groundwater flow 138. The number of non-zero flow rate settings of the pumps 136 is dependent on the increments (e.g., 1% maximum, 5% maximum, 25% maximum, continuous, etc.) at which the non-zero flow rate settings may be adjusted. For example, when the non-zero flow rate settings of the pumps 136 may be adjusted in 25% maximum increments, the pumps 136 may have non-zero flow rate settings of 25% maximum, 50% maximum, 75% maximum and 100% maximum. Thus, when a single pump 136 is configured with these four flow rate settings it may be operated to generate four different flow rates of the groundwater flow 138, and, when the pumps 136A and 136B are configured with these flow rate settings, they may be operated in a staggered manner to generate eight different non-zero flow rates of the groundwater flow 138, for example.

[0084] Some embodiments of the present disclosure are directed to methods of controlling the operation of one or more groundwater heat exchangers 102 of each heat exchange unit 101 to provide a desired rate of heat exchange between the groundwater 110 and the loop fluid flow 112 indicated by the heat exchange demand input, such as to meet the needs of a heat exchange operation being performed by the heat pump 118.

[0085] FIG. 5 is a flowchart illustrating a method of controlling the groundwater heat exchange system 100 to regulate a temperature of the loop fluid flow 112 using one or more of the groundwater units 101, in accordance with embodiments of the present disclosure. The method may be implemented by the controller 150. It is understood that the steps of the method of FIG. 5 described below are repeated a limited number of times.

[0086] In some embodiments, the method begins with the driving of the loop fluid flow 112 through the loop fluid pathway 104 using the pump 114, as indicated at 160 of the method and illustrated in FIG. 1. Here, the controller 150 may open the valve 132 to allow the loop fluid flow 112 to travel through the groundwater heat exchanger 102 of the unit 101, and/or control the pump 114.

[0087] At 160, at least one groundwater pump 136 of the unit 101 may be activated at an initial flow rate setting. The initial flow rate setting may be the zero flow rate setting, or one of the non-zero flow rate settings, such as a minimum non-zero flow rate setting (e.g., 25% maximum) for the pump 136. In some embodiments, the initial flow rate setting of the pump 136 is set based on the heat exchange demand input received or determined by the controller 150. Thus, if the heat exchange demand input indicates no demand for heat exchange, the controller 150 may keep the pump 136 in the zero flow rate setting or deactivated state, and if the heat exchange demand input indicates a demand for increased heat exchange, the controller 150 may set the pump 136 in one of the non-zero flow rate settings. Thus, the pump 136 may not be activated until a demand for increased heat exchange is received.

[0088] At 164 of the method, heat is transferred or exchanged between the groundwater 110 (e.g., the groundwater flow 138) and the loop fluid flow 112 using the heat exchanger 102. That is, heat is exchanged from the groundwater 110 through the heat exchange piping of the groundwater heat exchanger 102 to the loop fluid flow 112 traveling through the heat exchange piping 117 (FIG. 1).

[0089] At 166, a determination is made as to whether the flow rate setting of the pump 136 should be adjusted by the controller 150 based on a heat exchange demand input, which indicates whether the loop fluid flow is within setpoint parameters. As discussed above, the heat exchange demand input may take the form of a command or input 152 received from a source, such as a controller of the heat pump 118, for example. Alternatively, the heat exchange demand input may be determined by the controller 150 based on a setpoint temperature and a temperature of the loop fluid flow 112, such as that detected by the sensor 142A, as discussed above, for example.

[0090] In some embodiments, the heat exchange demand input indicates a state of no demand for heat exchange when the temperature of the loop fluid flow 112 is within the setpoint parameters, and indicates a state of demand for increased heat exchange when the temperature of the loop fluid flow 112 calls for a greater rate of heat exchange with the groundwater 110. In some embodiments, the heat exchange demand input may indicate a state of decreased demand for heat exchange, as discussed above. [0091] When the heat exchange demand input indicates a state of no demand for heat exchange in step 166, the method returns to 164, and the system 100 continues its current operation without adjusting the flow rate setting of the groundwater pump 136.

[0092] If, in step 166, the heat exchange demand input indicates that an adjustment (increase or decrease) to the heat exchange between the groundwater 110 and the loop fluid flow 112 is desired, the method moves to either step 168 or step 170 of the method where the flow rate setting of one or more of the pumps 136 is adjusted by the controller 150.

[0093] In some embodiments, before adjusting the flow rate setting of any of the pumps 136 in steps 168 and 170 when the heat exchange demand input transitions to a new state of heat exchange demand (no demand, demand for increase heat exchange, demand for decreased heat exchange), a predetermined delay is imposed by the controller 150. The delay allows the heat exchange demand input to reach a stable state and prevent the controller 150 from making rapid adjustments to the flow rate setting of the pump 136, such as transitions between the zero flow rate setting and one of the non-zero How rate settings. The imposed delay period may be set based on a delay time setting stored in the memory 156 of the system 100, for example. Examples of the predefined delay time include 1 -5 minutes, such as 3 minutes, or another suitable delay time.

[0094] When the method moves to step 168 in response to the heat exchange demand input indicating a state of demand for increased heat exchange, the controller 150 adjusts the flow rate setting of one or more of the pumps 136 of the heat exchange unit 101.

[0095] When the unit 101 includes a single groundwater pump 136 (e.g., pump 136A), step 168 involves increasing the flow rate of the groundwater flow 138 generated by the pump 136 by adjusting its flow rate setting using the controller 150, and step 170 involves decreasing the flow rate of the groundwater flow 138 generated by the pump 136 by adjusting its flow rate setting using the controller 150.

[0096] For example, if the heat exchange demand input transitions from indicating no demand to indicating a demand for increased heat exchange in step 166, the flow rate setting of the pump 136 may be transitioned from the zero flow rate setting to one of the non-zero flow rate settings (e.g., 25% maximum) and the method may return to step 164. Subsequently, when the method returns to step 166, possibly after a delay period, if the heat exchange demand input continues to indicate a demand for increased heat exchange, the controller 150 may adjust the flow rate setting of the pump 136 to another non-zero flow rate setting (e.g., 50% maximum) to further increase the flow rate of the groundwater flow 138.

[0097] Likewise, when the heat exchange demand input indicates a decreased demand for heat exchange in step 166, the controller 150 may adjust the flow rate setting of the pump 136 to decrease the flow rate of the groundwater flow 138, and return to step 164. This may be repeated until the controller 150 deactivates the pump 136 by setting it to in the zero flow rate setting.

[0098] The changes to the flow rate setting of the pump 136 in steps 168 and 170 by the controller 150 may be in accordance with the embodiments described above, such as incremental adjustments to the flow rate settings. Thus, the flow rate setting of the pump 136 may be adjusted to a next higher or lower preset level at predefined increments, such as 25% maximum increments, or other suitable increments. Increases to the flow rate setting of the pump 136 in step 168 may be allowed until the groundwater pump 136 reaches the maximum non-zero flow rate setting (e.g., 100% maximum). Decreases to the flow rate setting of the pump 136 may be allowed until the groundwater pump 136 reaches the zero flow rate setting, in which the pump 136 is deactivated.

[0099] The method of FIG. 5 also applies to the system 100 comprising a heat exchange unit 101 having multiple groundwater pumps 136, such as pumps 136A and 136B as shown in FIG. 1. Here, steps 160, 162 and 164 generally operate as indicated above. When, at 166, the heat exchange demand input indicates a demand for increased or decreased heat exchange, the method moves to either step 168 or 170 and the flow rate setting of one or more of the pumps 136 is adjusted to either increase or decrease the flow rate of the groundwater flow 138.

[00100] The adjustment of the flow rate settings of the pumps 136 in steps 168 and 170 may be made in parallel or in a staggered manner by the controller 150. When the flow rate settings are adjusted in a parallel manner, the flow rate settings of the pumps 136 are adjusted in unison to generate the desired change in the flow rate of the groundwater flow or flows 138 produced by the pumps 136. Such parallel adjustments to the flow rate settings may be in accordance with the incremental adjustments described above, or through another suitable technique.

[00101] When the controller 150 adjusts the flow rate settings in a staggered manner, the flow rate setting of one of the pumps 136 is adjusted at a time in steps 168 and 170. In one example, the controller 150 initially performs each of adjusting steps 168 and 170 using only one of the groundwater pumps 136, such as pump 136A, while the other pumps 136 are in the zero flow rate setting. Thus, the method may operate using the pump 136A as described above until the groundwater pump 136A reaches its maximum non-zero flow rate setting after an adjustment in step 168. Here, after repeating step 164 and optionally adding in a delay period, if the heat exchange demand input continues to indicate a state of increased demand for heat exchange in step 166, the controller 150 responds to this situation in step 168 by activating another pump 136, such as the pump 136B, such that both pumps 136A and 136B operate in one of their non-zero flow rate settings. In one embodiment, the non-zero flow rate settings of the pumps 136A and 136B are initially set to non-zero flow rate settings (e.g., 50% maximum) that produce a flow rate of the groundwater flow 138 that is higher than the flow rate of the groundwater flow 138 produced when the single groundwater pump 136 is operating at its maximum non-zero flow rate setting.

[00102] As the method progresses through repetitions of steps 164, 166 and 168 or 170, the flow rate settings of the pumps 136A and 136B may be adjusted in an incremental manner to meet the demand indicated by the heat exchange demand input. In some embodiments, the controller 150 may adjust the flow rate settings of the pumps 136A and 136B in step 168 or 170 based on a mapping of incremental adjustments stored in the memory that correspond to incremental changes to the flow rate of the groundwater flow 1 8, or by using another suitable technique. The mapping may cause the controller 150 to adjust one or both of the pumps 136A and 136B in steps 168 and 170. In another example, the controller 150 may alternate adjusting the flow rate settings of the pumps 136A and 136B in steps 168 and 170. This has the effect of balancing the workload of the pumps 136 and increasing the overall lifespan of the group of pumps 136.

[00103] One embodiment of the control method involves minimizing or reducing the energy consumption of the groundwater pumps 136 while satisfying the heat exchange demand input. Since the energy used by the groundwater pumps 136 may increase significantly above a certain threshold flow rate setting, typically around 50% maximum, the method generally operates to maintain the flow rate settings of the pumps 136 at or below this flow rate setting.

[00104] In one example, step 162 involves initially activating one of the groundwater pumps 136 while the other pumps 136 remain deactivated. For example, the groundwater pump 136A may be set to an initial non-zero flow rate setting in step 162, such as a minimum non-zero flow rate setting (e.g., 25% maximum). The groundwater pump 136A may be incrementally adjusted in steps 168 and 170 as necessary to meet the heat exchange demand input. As the demanded heat exchange rate increases, the groundwater pump 136A may be incrementally increased until it reaches a pump stage start setpoint stored in the memory 156, at which another groundwater pump 136, such as pump 136B, may be activated by the controller 150 in step 168.

[00105] In one embodiment, the pump stage start setpoint is dependent upon the number of groundwater pumps 136 in the unit 101 or system 100. In one example, the pump stage start setpoint may be determined by the following equation:

Pump Stage Start Setpoint = (n + l)*(Minimum Speed)/n where n is equal to the number of activated groundwater pumps 136.

[00106] Thus, for the groundwater heat pumps 136 of the example system 100 of FIGS. 1, 2 or 3, the groundwater pump 136A may initially be activated in step 162 and adjusted as described above in steps 168 and 170 until the groundwater pump 136A reaches the pump stage start setpoint (e.g., 50% maximum). At this point, the groundwater pump 136B may be activated. Initially, the non-zero flow rate settings of both pumps 136A and 136B may be set to a predetermined minimum non-zero flow rate setting, such as 25% maximum, for example.

[00107] In another example, when both pumps 136A and 136B are operating in one of their non-zero flow rate settings and the heat exchange demand input indicates a state of decreased demand for heat exchange in step 166, the method moves to the adjusting step 170, in which the controller 150 adjusts the pump 136B to its zero flow rate setting, while the pump 136A is operated at one of its non-zero flow rate settings to decrease the flow rate of the groundwater flow 138. By utilizing only the pumps 136 that are required to provide the desired flow rate of the groundwater flow 138, the lifespan of the pumps 136 may be increased.

[00108] In another example, when the pump 136 A operates at a relatively lower power than the pump 136B, the pump 136A is deactivated, the pump 136B is operating in one of the nonzero flow rate settings (e.g., 50% maximum), and the heat exchange demand input indicates a state of decreased demand for heat exchange in step 166, the method moves to the adjusting step 170, in which the controller 150 adjusts the flow rate setting of the pump 136B to its zero flow rate setting and operates the pump 136A at one of its non-zero flow rate settings, such as at a high flow rate setting (e.g., greater than 50% maximum, 75% maximum, or 100% maximum) to maintain or decrease the flow rate of the groundwater flow 138 while maximizing power consumption efficiency.

[00109] In yet another example, when the pump 136A operates at a relatively lower power than the pump 136B, the pump 136A is operating at its maximum non-zero flow rate setting (100% maximum), the pump 136B is deactivated, and the heat exchange demand input indicates a demand for increased heat exchange in step 166, the method moves to the adjusting step 168, in which the controller 150 adjusts the flow rate setting of the pump 136A to its zero flow rate setting and operates the pump 136B at one of its non-zero flow rate settings to increase the flow rate of the groundwater flow 138 while maximizing power consumption efficiency.

[00110] In some embodiments, the method operates to periodically run each of the one or more groundwater pumps 136 during periods when the heat exchange demand input indicates a state of no demand for heat exchange to maintain the operability of the pumps 136. Thus, in some embodiments of the method, when the heat exchange demand input analyzed in step 166 by the controller 150 continuously indicates no demand for heat exchange for a no demand period stored in the memory, or after a cycle count stored in the memory 156 corresponding to the number of cycles of steps 164 and 166, the controller 150 operates one or both of the pumps 136 in a non-zero flow rate setting for an operational period stored in the memory 156. In some embodiments, the controller 150 alternates its selection of the pump 136 to operate among the group of pumps 136 to ensure that all of the pumps 136 are periodically operated.

[00111] One embodiment of step 166 includes sensing the temperature of the loop fluid flow 1 12 using a temperature sensor, such as sensor 142A or 142B, comparing the sensed temperature to a setpoint temperature, and determining the heat exchange demand input based on the comparison, using the controller 150. For example, the setpoint temperature may indicate a desire for the loop fluid flow 112 supplied to the heat pump 118 through the supply pipe 116B to be less than a setpoint temperature for a cooling operation. If the supply loop fluid flow temperature detected by the sensor 142A indicates a temperature that is less than the setpoint temperature, the heat exchange demand input may be determined to have a state of no demand for heat exchange. If the supply loop fluid flow temperature detected by the sensor 142A indicates a temperature that is greater than the setpoint temperature, the heat exchange demand input may be determined to have a state of demand for increased heat exchange. If the supply loop fluid flow temperature detected by the sensor 142A indicates a temperature that is less than the setpoint temperature by a predefined margin, the heat exchange demand input may be determined to have a state of demand for decreased heat exchange. These examples would be reversed when the heat pump 118 is using the loop fluid flow for a heating operation.

[00112] Some embodiments are directed to a method of controlling the delivery of the loop fluid flow 112 to the heat exchange units 101 of the system 100 to regulate the heat exchange between the loop fluid flow 112 and the groundwater 110 based on a flow rate of the loop fluid flow 112. Here, the system 100 includes the valving 129 for controlling the delivery of the loop fluid flow 112 to the heat exchange units 101 and a flow rate sensor 140 configured to detect a flow rate of the loop fluid flow 112, as indicated in FIG. 1. Since the flow rate of the loop fluid flow 112 may be regulated by the loop fluid pump 114 based on, for example, a setpoint temperature or a heat exchange demand of the heat pump 118, the flow rate of the loop fluid flow 112 may be used as the heat exchange demand input for the controller 150. Thus, a high flow rate of the loop fluid flow 112 may indicate a demand for increased heat exchange, whereas a low flow rate of the loop fluid flow may indicate no demand for heat exchange.

[00113] In the method, which is performed using the controller 150, the valve 132A may initially be open to allow the loop fluid flow to travel through the unit 101A while the valves 132B and 132C are closed to prevent the loop fluid flow 112 from circulating through the units 101B and 101C. The flow rate of the loop fluid flow 112 is detected using the flow rate sensor 140 and the detected flow rate is compared to a threshold flow rate stored in the memory 156 using the controller 150. When the detected flow rate is below the threshold flow rate it represents a heat exchange demand input indicating no demand for heat exchange, and when the detected flow rate is above the threshold flow rate it represents a heat exchange demand input indicating a demand for increased heat exchange.

[00114] When the flow rate indicates a demand for increased heat exchange, the controller 150 actuates another valve 132, such as valve 132B to circulate the loop fluid flow 112 through both of the units 101 A and 10 IB and increase the rate of heat exchange between the loop fluid flow 112 and the groundwater 110 in the bores 106A and 106B. If, after a predetermined delay period, the detected flow rate of the loop fluid flow 112 remains above the threshold flow rate indicating a demand for increased heat exchange, then the controller 150 may actuate the valve 132C to circulate the loop fluid flow 112 through the units 101 A, 101B and 101C to further increase the total rate of heat exchange with the loop fluid flow 112.

[00115] When the detected flow rate of the loop fluid flow 112 transitions from above the threshold flow rate to below the threshold flow rate while two or more of the valves 132 are in their open states to allow the loop fluid flow to circulate through the corresponding units 101, the controller 150 may actuate one of the valves 132 to its closed state to block the circulation of the loop fluid flow 112 through the corresponding unit 101, and reduce the rate of heat exchange between the loop fluid flow 112 and the groundwater. This may be repeated after suitable delay times until only one of the valves 132 remains open and the loop fluid flow 112 is circulated through one of the units 101.

[00116] As discussed above, some embodiments of the system 100 include a bypass pipe 135 that connects the loop fluid supply pipe 116B to the loop fluid return pipe 116A, and a bypass valve 134 that controls a flow of the loop fluid through the bypass pipe 135, as shown in FIG. 1. In one embodiment, the controller 150 opens the valve 134 when the pumps 136 of the system 100 are operating close to their minimum speed to prevent them from starting or stopping frequently, which may cause excess wear and tear and reduce the lifespan of the pumps 136.

[00117] In some embodiments, the method comprises adjusting the bypass valve 134 based on the heat exchange demand input using the controller 150. In some embodiments, the adjustment to the bypass valve 134 is based on the temperatures detected by the sensors 142A and/or 142B. This operation controls a flow of the loop fluid that passes between the pipes 116A and 116B through the bypass pipe 135, which may be used to adjust the temperature of the loop fluid flow 112 supplied to the heat pump 118 and/or the temperature of the loop fluid flow 112 returned to the one or more heat exchange units 101.

[00118] In some embodiments, the system 100 includes multiple groundwater heat exchangers 102 that are contained within the same borehole 106, as discussed above with reference to FIG. 2. The heat exchangers 102 may form components of a single heat exchange unit 101 (e.g., unit 101A) or multiple heat exchange units 101. In this case, the method of FIG. 5 may operate substantially as discussed above but with the controller 150 controlling the operation of additional groundwater pumps 136 to “activate” selected groundwater heat exchangers 102, which otherwise operate in a passive manner. Accordingly, the heat exchanging step 164 may be performed using each of the heat exchangers 102 contained within the borehole 106.

[00119] In some embodiments, the system 100 includes multiple groundwater heat exchange units 101 that are each contained within separate boreholes 106, as discussed above with reference to FIG. 3. In this case, each heat exchange unit 101 may be operated by the controller 150 in accordance with embodiments of the method of FIG. 5 described above. Accordingly, the heat exchanging step 164 may be performed using each of the heat exchange units 101.

[00120] In one embodiment, the controller 150 may operate to trigger an alarm and/or a notification (e.g., email, text message, etc.) to an administrator upon detecting an abnormal condition in the system 100. The abnormal condition may be detected based on a ratio of the rate of the groundwater flow 138 (e.g., based on groundwater pump flow rate setting) to the rate of the loop fluid flow 112 (e.g., based on the output from the differential pressure sensor) that meets a threshold value and may indicate an issue with the one or more heat exchangers 102 or pumps 136, such as a groundwater flow blockage, for example.

[00121] Although the embodiments of the present disclosure have been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present disclosure.

Claims

WHAT IS CLAIMED IS:

1. A groundwater heat exchange system for regulating a temperature of a loop fluid flow pumped through a closed loop fluid pathway for use by a heat pump, the system comprising: one or more groundwater heat exchange units, each groundwater heat exchange unit comprising: a heat exchanger submersed in groundwater within a borehole, and configured to facilitate heat exchange between the groundwater and the loop fluid flow; and at least one groundwater pump each having a plurality of flow rate settings including a zero flow rate setting, in which the groundwater pump is in a deactivated state and does not drive a flow of the groundwater, and a plurality of non-zero flow rate settings corresponding to different non-zero flow rates at which the groundwater pump drives a flow of the groundwater through the heat exchanger; and a controller configured to adjust the flow rate settings of the at least one groundwater pump based on a heat exchange demand input, which indicates any one of a plurality of states of demand for heat exchange between the groundwater and the loop fluid flow including no demand for heat exchange and a demand for increased heat exchange.

2. The groundwater heat exchange system of claim 1, wherein, the at least one groundwater pump includes a first groundwater pump, and the controller adjusts the flow rate setting of the first groundwater pump to incrementally increase or decrease the flow rate of the corresponding flow of the groundwater based on the heat exchange demand input.

3. The groundwater heat exchange system of claim 1, wherein the controller imposes a predetermined delay based on a delay setting in response to a change in the heat exchange demand input before adjusting the flow rate setting of the at least one groundwater pump.

4. The groundwater heat exchange system of claim 1, wherein: the at least one groundwater pump includes a first groundwater pump configured to drive a first flow of the groundwater through the groundwater heat exchanger and a second groundwater pump configured to drive a second flow of the groundwater through the heat exchanger; and the controller adjusts the flow rate setting of the first groundwater pump and/or the flow rate setting of the second groundwater pump based on the heat exchange demand input.

5. The groundwater heat exchange system of claim 4, wherein the controller adjusts the flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in parallel based on the heat demand input.

6. The groundwater heat exchange system of claim 4, wherein the controller adjusts flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in a staggered manner based on the heat demand input.

7. The groundwater heat exchange system of claim 6, wherein: the controller transitions the first groundwater pump to one of the non-zero flow rate settings to increase a flow rate of the first flow to meet a demand for increased heat exchange indicated by the heat exchange demand input while the second groundwater pump is in the zero flow rate setting; and when the first groundwater pump is operating at a maximum non-zero flow rate setting and the second groundwater pump is in the zero flow rate setting, the controller operates each of the first and second groundwater pumps in one of the non-zero flow rate settings in response to the heat exchange demand input indicating a demand for increased heat exchange.

8. The groundwater heat exchange system of claim 6, wherein: when the heat exchange demand input transitions from indicating no demand for heat exchange to indicating a demand for increased heat exchange, the controller initially transitions the first groundwater pump from the zero flow rate setting to one of the non-zero flow rate settings while the second groundwater pump remains in the zero flow rate setting; and subsequently, when the heat exchange demand input transitions from indicating no demand for heat exchange to indicating a demand for increased heat exchange, the controller initially transitions the second groundwater pump from the zero flow rate setting to one of the non-zero flow rate settings while the first groundwater pump remains in the zero flow rate setting. roundwater heat exchange system of claim 6, wherein: the states of demand for heat exchange between the groundwater and the loop fluid flow indicated by the heat exchange demand input include a demand for decreased heat exchange; and when the first and second groundwater pumps are each operating in one of their non-zero flow rate settings, the controller adjusts the second groundwater pump to the zero flow rate setting when the heat exchange demand input indicates a demand for decreased heat exchange. groundwater heat exchange system of claim 6, wherein: the states of demand for heat exchange between the groundwater and the loop fluid flow indicated by the heat exchange demand input include a demand for decreased heat exchange; the first groundwater pump operates at a lower power than the second groundwater pump; and when the heat exchange demand input transitions to indicating a demand for decreased heat exchange while the second groundwater pump is operating at a 50% maximum non-zero flow rate setting or less and the first groundwater pump is in the zero flow rate setting, the controller transitions the second groundwater pump to the zero flow rate setting and operates the first groundwater pump at its maximum non-zero flow rate setting.

11. The groundwater heat exchange system of claim 6, wherein: the first groundwater pump operates at a lower power than the second groundwater pump; and when the first groundwater pump is operating at its maximum non-zero flow rate setting and the heat exchange demand input indicates a demand for increased heat exchange, the controller operates the first groundwater pump in the zero flow rate setting and operates the second groundwater pump in one of the non-zero flow rate settings.

12. The groundwater heat exchange system of claim 4, wherein the controller periodically transitions each of the first and second groundwater pumps from the zero flow rate setting to one of the non-zero flow rate settings during periods when the heat exchange demand input indicates no demand for heat exchange.

13. The groundwater heat exchange system of claim 1, wherein: the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the plurality of heat exchangers, and a loop fluid return pipe, through which the loop fluid flow is returned to the plurality of heat exchangers; the system includes a temperature sensor having a temperature output that is indicative of a temperature of the loop fluid flow; and the heat exchange demand input is based on a difference between a setpoint temperature and the temperature of the loop fluid flow indicated by the temperature output.

14. The groundwater heat exchange system of claim 13, wherein the temperature output is indicative of the temperature of the loop fluid flow in the supply pipe.

15. The groundwater heat exchange system of claim 1, wherein: wherein the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the plurality of heat exchangers, and a loop fluid return pipe, through which the loop fluid flow is returned to the plurality of heat exchangers; and the system includes a bypass pipe connecting the loop fluid supply pipe to the loop fluid return pipe and a bypass valve configured to regulate a flow of the loop fluid between the loop fluid supply and return pipes through the bypass pipe.

16. The groundwater heat exchange system of claim 1, wherein: the one or more groundwater heat exchange units comprise a first groundwater heat exchange unit and a second groundwater heat exchange unit; and the heat exchangers of the first and second groundwater heat exchange units are each positioned within the same borehole.

17. The groundwater heat exchange system of claim 1, wherein: the one or more groundwater heat exchange units comprise a first groundwater heat exchange unit and a second groundwater heat exchange unit; the heat exchanger of the first groundwater heat exchange unit is positioned within a first borehole; and the heat exchanger of the second groundwater heat exchange unit is positioned within a second borehole that is displaced from the first borehole.

18. The groundwater heat exchange system of claim 17, wherein: the system includes: valving configured to selectively circulate the loop fluid flow through one or both of the first and second groundwater heat exchange units; and a flow rate sensor configured to detect a flow rate of the loop fluid flow upstream of the valving; the controller is configured to compare the detected flow rate to a threshold flow rate; when the flow rate of the loop fluid flow is below the threshold flow rate, the controller actuates the valving to circulate the loop fluid flow through the first groundwater heat exchange unit and to block the loop fluid flow from being circulated through the second groundwater heat exchange unit; and when the flow rate of the loop fluid flow is above the threshold flow rate, the controller actuates the valving to circulate the loop fluid flow through the first and second groundwater heat exchange units.

19. A method of controlling a groundwater heat exchange system for regulating a temperature of a loop fluid flow pumped through a closed loop fluid pathway for use by a heat pump, the groundwater heat exchange system comprising: a groundwater heat exchange unit comprising: a heat exchanger submersed in groundwater within a borehole, and configured to facilitate heat exchange between the groundwater and the loop fluid flow; and at least one groundwater pump each having a plurality of flow rate settings including a zero flow rate setting, in which the groundwater pump is in a deactivated state and does not drive a flow of the groundwater, and a plurality of non-zero flow rate settings corresponding to different non-zero flow rates at which the groundwater pump drives a flow of the groundwater through the heat exchanger; and a controller configured to adjust the flow rate settings of the at least one groundwater pump based on a heat exchange demand input, which indicates any one of a plurality of states of demand for heat exchange between the groundwater and the loop fluid flow including no demand for heat exchange and a demand for increased heat exchange, the method comprising steps of: exchanging heat between the groundwater and the loop fluid flow using the heat exchanger; adjusting the flow rate setting of one or more of the at least one groundwater pump based on a heat exchange demand input using the controller; and repeating the exchanging and adjusting steps a limited number of times.

20. The method of claim 19, wherein: the at least one groundwater pump includes a first groundwater pump; and the adjusting step comprises adjusting the flow rate setting of the first groundwater pump to incrementally increase or decrease the flow rate of the corresponding flow of the groundwater based on the heat exchange demand input.

21. The method of claim 20, wherein the adjusting step comprises delaying adjusting the flow rate setting of the first groundwater pump for a predetermined delay time based on a delay setting in response to a change in the heat exchange demand input received in the receiving step.

22. The method of claim 19, wherein: the at least one groundwater pump includes a first groundwater pump configured to drive a first flow of the groundwater through the groundwater heat exchanger and a second groundwater pump configured to drive a second flow of the groundwater through the heat exchanger; and the adjusting step comprises adjusting the flow rate setting of the first groundwater pump and/or the flow rate setting of the second groundwater pump based on the heat exchange demand input.

23. The method of claim 22, wherein the adjusting step comprises adjusting the flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in parallel based on the heat demand input.

24. The method of claim 22, wherein the adjusting step comprises adjusting the flow rate setting of the first groundwater pump and the flow rate setting of the second groundwater pump in a staggered manner based on the heat demand input.

25. The method of claim 24, wherein: when the heat exchange demand input indicates a demand for increased heat exchange, the first groundwater pump is operating in a non-zero flow rate setting that is less than a maximum non-zero flow rate setting and the second groundwater pump is in the zero flow rate setting, the adjusting step comprises incrementally adjusting the first groundwater pump to one of the non-zero flow rate settings to increase the flow rate of the first flow while the second groundwater pump remains in the zero flow rate setting; and when the heat exchange demand input indicates a demand for increased heat exchange, the first groundwater pump is operating in the maximum non-zero flow rate setting and the second groundwater pump is in the zero flow rate setting, the adjusting step comprises adjusting each of the first and second groundwater pumps to one of their non-zero flow rate settings.

26. The method of claim 24, wherein in a series of the adjusting steps, the flow rate settings of the first and second groundwater pumps are adjusted on an alternative basis.

27. The method of claim 24, wherein: the states of demand for heat exchange between the groundwater and the loop fluid flow indicated by the heat exchange demand input include a demand for decreased heat exchange; and when the first and second groundwater pumps are each operating in one of their non-zero flow rate settings and the heat exchange demand input indicates a demand for decreased heat exchange, the adjusting step comprises operating the first groundwater pump in one of the non-zero flow rate settings and adjusting the flow rate setting of the second groundwater pump to the zero flow rate setting. method of claim 24, wherein: the states of demand for heat exchange between the groundwater and the loop fluid flow indicated by the heat exchange demand input include a demand for decreased heat exchange; and the first groundwater pump operates at a lower power than the second groundwater pump; and when the second groundwater pump is operating at 50% of its maximum non-zero flow rate setting or less, the first groundwater pump is in the zero flow rate setting and the heat exchange demand input transitions to indicating a demand for decreased heat exchange, the adjusting step comprises adjusting the flow rate setting of the second groundwater pump to the zero flow rate setting and adjusting the flow rate setting of the first groundwater pump to its maximum non-zero flow rate setting. method of claim 24, wherein: the first groundwater pump operates at a lower power than the second groundwater pump; and when the first groundwater pump is operating at its maximum non-zero flow rate setting, the second groundwater pump is set to the zero flow rate setting, and the heat exchange demand input indicates a demand for increased heat exchange, the adjusting step comprises adjusting the flow rate setting of the first groundwater pump to the zero flow rate setting and adjusting the flow rate setting of the second groundwater pump to one of the non-zero flow rate settings.

30. The method of claim 22, wherein the adjusting step comprises periodically adjusting each of the first and second groundwater pumps from the zero flow rate setting to one of their non-zero flow rate settings during periods when the heat exchange demand input indicates no demand for heat exchange.

31. The method of claim 19, wherein the receiving step comprises: sensing a temperature of the loop fluid flow using a loop fluid temperature sensor; and determining the heat exchange demand input based on a comparison of the sensed temperature of the loop fluid to a setpoint temperature.

32. The method of claim 31, wherein: the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the heat exchanger, and a loop fluid return pipe, through which the loop fluid flow is returned to the heat exchanger; and sensing the temperature of the loop fluid flow comprises sensing the temperature of the loop fluid flow in the supply pipe.

33. The method of claim 19, wherein: the loop fluid pathway includes a loop fluid supply pipe, through which the loop fluid flow is supplied to the heat pump from the heat exchanger, and a loop fluid return pipe, through which the loop fluid flow is returned to the heat exchanger; the system includes a bypass pipe connecting the loop fluid supply pipe to the loop fluid return pipe and a bypass valve configured to regulate a flow of the loop fluid between the loop fluid supply and return pipes through the bypass pipe; and the method comprises adjusting the bypass valve based on the heat exchange demand input using the controller.

34. The method of claim 19, wherein: the system includes a plurality of the groundwater heat exchange units; the heat exchangers of the plurality of groundwater heat exchange units are each positioned within the same borehole; and the exchanging step comprises exchanging heat between the groundwater and the loop fluid flow using the heat exchangers of the plurality of groundwater heat exchange units. method of claim 19, wherein: the system comprises a plurality of the groundwater heat exchange units including a first groundwater heat exchange unit and a second groundwater heat exchange unit; the heat exchanger of the first groundwater heat exchange unit is positioned within a first borehole; and the heat exchanger of the second groundwater heat exchange unit is positioned within a second borehole that is displaced from the first borehole. method of claim 35, wherein: the system includes: valving configured to selectively circulate the loop fluid flow through one or both of the first and second groundwater heat exchange units; and a flow rate sensor configured to detect a flow rate of the loop fluid flow upstream of the valving; the method includes: detecting the flow rate of the loop fluid flow using the flow rate sensor; comparing the detected flow rate to a threshold flow rate using the controller; actuating the valving to circulate the loop fluid flow through the first groundwater heat exchange unit and to block the loop fluid flow from circulating through the second groundwater heat exchange unit using the controller when the flow rate of the loop fluid flow is below the threshold flow rate; and actuating the valving to circulate the loop fluid flow through the first and second groundwater heat exchange units using the controller when the flow rate of the loop fluid flow is above the threshold flow rate.