Multi-working-condition adaptive heat exchange capacity testing system for middle-deep geothermal well

Abstract

The application provides a multi-working-condition adaptive heat exchange capacity testing system for a middle-deep geothermal well, which comprises a ground source side subsystem, an evaporation side subsystem, a condensation side subsystem and a PLC control subsystem; the ground source side subsystem, the evaporation side subsystem and the condensation side subsystem are integrated on a mobile platform, a screw water chiller and a closed cooling tower are arranged for double cooling and cooling down, and a thermometer and a heat meter are arranged on each circuit to monitor the water supply temperature, the return water temperature and the volume flow of the corresponding circuit in real time; secondly, the system is controlled in real time by the PLC control subsystem to realize the testing of the heat exchange capacity of different well types, the quantitative evaluation of engineering economy, the real-time accounting and cross-checking of double-way heat, and the improvement of the well type adaptability and the accuracy of benefit measurement of the system.

Description

Technical Field

[0001] This application relates to the technical field of geothermal energy heat exchange capacity testing systems, and in particular to a multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system. Background Technology

[0002] Geothermal energy is a clean, stable, and renewable energy source with broad application prospects in building heating and industrial heat supply. Medium-deep geothermal well downhole heat exchange systems can extract heat from the soil and rock at depths of 2000-3000 meters through a closed-loop system. This process uses a "heat extraction without water extraction" method, thus having minimal impact on the geological environment, and has become one of the important energy sources for clean heating in northern my country. However, geothermal wells come in various types, including U-shaped, L-shaped, and coaxial casing wells. Existing geothermal well heat exchange capacity testing devices suffer from poor adaptability to different well types and inaccurate benefit calculations, which are pain points in the industry. Summary of the Invention

[0003] The purpose of this application is to provide a multi-condition adaptive system for testing the heat exchange capacity of medium-deep geothermal wells, thereby solving the technical problems of poor well type adaptability and inaccurate benefit calculation in existing geothermal well heat exchange capacity testing devices. The specific technical solution is as follows: This application provides a multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, including: a ground source side subsystem, comprising a plate heat exchanger, a first inlet pipe, and a first outlet pipe, wherein the first inlet pipe is connected to the primary side inlet of the plate heat exchanger, and the first outlet pipe is connected to the primary side outlet of the plate heat exchanger; a first thermometer a and a first heat meter are installed on the first inlet pipe, and a second thermometer a is installed on the first outlet pipe; and an evaporation side subsystem, comprising a spiral... The system includes a screw chiller unit, a second inlet pipe, and a second outlet pipe. One end of the second inlet pipe is connected to the secondary side outlet of the plate heat exchanger, and the other end is connected to the primary side inlet of the screw chiller unit. A third thermometer and a third heat meter are installed on the second inlet pipe. One end of the second outlet pipe is connected to the primary side outlet of the screw chiller unit, and the other end is connected to the secondary side inlet of the plate heat exchanger. A fourth thermometer is installed on the top; the condensing side subsystem includes a closed cooling tower, a third inlet pipe, and a third outlet pipe. One end of the third inlet pipe is connected to the secondary side outlet of the screw chiller unit, and the other end is connected to the inlet of the closed cooling tower. A fifth thermometer a and a fifth heat meter are installed on the third inlet pipe; one end of the third outlet pipe is connected to the outlet of the closed cooling tower, and the other end is connected to the secondary side inlet of the screw chiller unit. A sixth thermometer is installed on the third outlet pipe; the PLC control subsystem includes a PLC control cabinet. The signal input terminals of the PLC control cabinet are electrically connected to the first thermometer a, the first heat meter, the second thermometer a, the third thermometer, the third heat meter, the fourth thermometer, the fifth thermometer a, the fifth heat meter, and the sixth thermometer, respectively; the PLC control cabinet has a preset algorithm for testing and verifying the heat exchange capacity of each type of geothermal well.

[0004] In one possible implementation, a second circulation pump is provided on the first outlet pipe, a fourth circulation pump and a fourth electric three-way regulating valve are provided on the second outlet pipe, a fifth electric three-way shut-off valve is provided on the third inlet pipe, and a sixth circulation pump and a sixth electric three-way shut-off valve are provided on the third outlet pipe.

[0005] In one possible implementation, the control output terminal of the PLC control cabinet is electrically connected to the frequency converters of the second circulating pump, the fourth circulating pump, and the sixth circulating pump, as well as the fourth electric three-way regulating valve, the fifth electric three-way shut-off valve, and the sixth electric three-way shut-off valve.

[0006] In one possible implementation, the PLC control subsystem further includes a human-machine interface connected to the PLC control cabinet; the output of the PLC control cabinet is connected to the control loop of the closed cooling tower, and the PLC control cabinet is bidirectionally connected to the communication interface of the screw chiller unit.

[0007] In one possible implementation, the geothermal well type includes U-shaped wells, L-shaped wells, and coaxial casing wells.

[0008] In one possible implementation, the heat exchange capacity testing and verification algorithm for each type of geothermal well includes: a well-type heat exchange correction sub-algorithm, used to introduce corresponding correction coefficients for the U-shaped well, the L-shaped well, and the coaxial casing well to correct the original heat exchange; a multi-condition programmed test control sub-algorithm, which incorporates three types of well-type test processes: the U-shaped well executes a stepped variable flow steady-state test process, the L-shaped well executes a single-branch and multi-branch parallel comparison test process, and the coaxial casing well executes a high-low temperature cyclic hot-cold alternation test process; and an engineering economics quantitative evaluation sub-algorithm, which sums the total construction cost of all geothermal wells, the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, the cost of the outdoor power grid, and the cost of the machine room construction to obtain the static total investment of the project; and divides the static total investment of the project by the preset annual net savings in geothermal system operating costs to obtain the static... Investment recovery period; Dual-path real-time heat calculation and cross-validation sub-algorithm, synchronously collects temperature and flow data on each pipeline of the ground source subsystem and the condensation subsystem, calculates the total heat released by the geothermal rock and soil to the circulating medium per unit time and the total heat removed from the test loop by the cooling system per unit time based on the temperature data, the flow data and preset formulas; accumulates the total heat released by the geothermal rock and soil to the circulating medium per unit time to obtain the total heat exchange over the cumulative period; accumulates the total heat removed from the test loop by the cooling system per unit time to obtain the total cooling capacity over the cumulative period; when the system is in thermal steady state, calculates the instantaneous heat relative error and the cumulative heat relative error over the cumulative period on both sides of the ground source subsystem and the condensation subsystem, and judges whether the data of the instantaneous heat relative error and the cumulative heat relative error over the cumulative period are qualified according to the preset threshold.

[0009] In one possible implementation, the well-type heat exchange correction sub-algorithm is used to introduce corresponding correction coefficients for the U-shaped well, the L-shaped well, and the coaxial casing well, respectively, to correct the original heat exchange; including: according to a first preset formula: Q=ρ×V×C p Calculate the original heat transfer Q using ×ΔT, where ρ is the density of water in kg / m³. 3 V represents the volumetric flow rate of water, in cubic meters per second (m³). 3 / s;C pΔT is the specific heat of water at constant pressure, expressed in kJ / (kg×℃); ΔT is the temperature difference between the inlet and outlet water temperatures of the system, expressed in ℃; and the friction loss correction factor is based on the preset U-shaped well depth. And the second preset formula: The heat transfer after correction of the U-shaped well was calculated. Based on the pre-set L-shaped well, the lateral heat transfer correction coefficient of the horizontal section of the formation is increased. And the third preset formula: The corrected heat transfer of the L-shaped well was calculated. Based on the preset radial heat conduction loss correction coefficient of the inner and outer pipes of the coaxial casing well. And the fourth preset formula: The corrected heat transfer of the coaxial casing well was calculated. .

[0010] In one possible implementation, the stepped variable flow steady-state test process involves setting multiple circulating flow rates step by step, maintaining each flow rate until thermal steady state and collecting heat transfer data to obtain the steady-state heat transfer performance parameters of the U-shaped well under different flow rates; the single-branch and multi-branch parallel comparison test process involves conducting independent tests on each branch to obtain independent test data, and conducting joint tests on multiple branches in parallel to obtain joint test data, and then comparing the independent test data and the joint test data to determine the degree of formation thermal interference and pipeline heat transfer uniformity between branches; the high and low temperature cyclic hot and cold alternation test process automatically alternates between simulating winter heat extraction and summer heat exhaust conditions, and collects bidirectional steady-state heat transfer data for both heat extraction and heat exhaust to evaluate the radial heat conduction loss of the wellbore.

[0011] In one possible implementation, the summation of the total construction cost of all geothermal wells, the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, the cost of the outdoor power grid, and the cost of the machine room construction, to obtain the static total investment of the project, includes: According to the fifth preset formula: Calculate the total construction cost of all geothermal wells. ;in, Cost of drilling and backfilling for a single well; The cost of the downhole heat exchange pipeline for the U-shaped well, L-shaped well, or coaxial casing well; N is the total number of geothermal wells; According to the sixth preset formula: Calculate the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system. ;in, Cost of testing hardware; Cost of circulating pump unit; Costs for manifolds, valves, and piping; Cost of the PLC control subsystem; Based on the total construction cost of all the aforementioned geothermal wells The total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system Cost of outdoor connection pipeline Computer room civil engineering cost And the seventh preset formula: Calculate the static total investment of the project ; The static investment payback period is obtained by dividing the total static investment of the project by the pre-set net savings in the annual operating cost of the geothermal system; including: According to the eighth preset formula: Calculate the amount of coal saved annually after adopting a geothermal system. ;in, The total heat exchange capacity of the geothermal system for heating throughout the year, expressed in kW; To convert the cumulative total heat exchange power into the total annual heat output using a conversion factor, ; The standard calorific value is taken as 29300 kJ / kg; The efficiency of a traditional coal-fired boiler is taken as 0.75. Based on the amount of coal saved annually after adopting the geothermal system And the ninth preset formula: Calculate the net annual operating cost savings of the pre-designed geothermal system. ;in, This refers to the market price per unit of standard coal. The total annual electricity cost for the geothermal circulation pump and testing system; Based on the project's static total investment and the annual net savings in operating costs of the pre-set geothermal system And the tenth preset formula: Calculate the static payback period .

[0012] In one possible implementation, the dual-path heat real-time calculation and cross-verification sub-algorithm synchronously collects temperature and flow data from each pipeline of the ground source subsystem and the condensation subsystem through the PLC control subsystem. Based on the temperature data, the flow data, and a preset formula, it calculates in real-time the total heat released by the geothermal rock and soil to the circulating medium per unit time and the total heat removed from the test loop by the cooling system per unit time. It then accumulates the total heat released by the geothermal rock and soil to the circulating medium per unit time to obtain the total heat exchange over a cumulative period; and accumulates the total heat removed from the test loop by the cooling system per unit time to obtain the total cooling capacity over a cumulative period. When the system is in a thermal steady state, it calculates the instantaneous relative heat error and the cumulative relative heat error over a cumulative period on both sides of the ground source subsystem and the condensation subsystem, and judges whether the data of the instantaneous relative heat error and the cumulative relative heat error over a cumulative period are qualified according to a preset threshold. This includes: synchronously collecting the water supply temperature of the ground source subsystem through the first thermometer a, the second thermometer a, and the first heat meter. Return water temperature and source-side volumetric flow ; and based on the collected water supply temperature The return water temperature The source-side volumetric flow rate And the eleventh preset formula: Calculate the total heat released by the geothermal rock mass to the circulating medium per unit time. ;in, This is the density of water, expressed in kg / m³. 3 The value is 1000 kg / m 3 ; This is the specific heat of water at constant pressure, expressed in kJ / (kg×℃), and is taken as 4.187 kJ / (kg∙℃). The water supply temperature of the condenser subsystem is simultaneously collected by the fifth thermometer a, the sixth thermometer, and the fifth heat meter. Return water temperature and condenser side volumetric flow rate ; and based on the collected water supply temperature The return water temperature The condensation side volumetric flow rate And the twelfth preset formula: Calculate the total heat removed from the test loop by the cooling system per unit time. ;in, This is the density of water, expressed in kg / m³. 3 The value is taken as 1000 kg / m 3 ; This is the specific heat of water at constant pressure, expressed in kJ / (kg×℃), and is taken as 4.187 kJ / (kg∙℃). Based on the total heat released by the geothermal rock and soil mass to the circulating medium per unit time And the thirteenth preset formula: Calculate the total heat exchange over the cumulative period ;in, The initial time, For cumulative time periods; Based on the total heat removed from the test circuit by the cooling system per unit time And the fourteenth preset formula: Calculate the total cooling load over the cumulative period ;in, The initial time, For cumulative time periods; When the system is in a thermal steady state, the total heat released by the geothermal rock and soil to the circulating medium per unit time is as described. and the total heat removed from the test loop by the cooling system per unit time. And the fifteenth preset formula: Calculation of relative error of instantaneous heat ; Based on the total heat exchange during the cumulative time period and the total cooling capacity during the cumulative period And the sixteenth preset formula: Calculating the relative error of cumulative heat over a period of time ; Preset first threshold Second threshold ,and ; The relative error of instantaneous heat With the first threshold The second threshold For comparison: when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. qualified; when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. If there is a slight deviation, the human-machine interface will display a prompt to check the instruments and pipeline insulation. when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. If the system fails, the human-computer interaction interface will display the abnormal time period and the cause of the failure. The relative error of the cumulative heat over the period With the first threshold The second threshold For comparison: when At that time, the total heat exchange during the cumulative period qualified; when At that time, the total heat exchange during the cumulative period If there is a slight deviation, the human-machine interface will display a prompt to check the instruments and pipeline insulation. when At that time, the total heat exchange during the cumulative period If the system fails, the human-computer interaction interface will display the abnormal time period and the cause of the failure.

[0013] The beneficial effects of this application's embodiments are as follows: This application provides a multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system. This system first integrates the ground source side subsystem, evaporation side subsystem, and condensation side subsystem onto a mobile platform. Secondly, it is equipped with a screw chiller unit and a closed-loop cooling tower for dual cooling. Thermometers and heat meters are installed on each loop to monitor the supply water temperature, return water temperature, and corresponding volumetric flow rate in real time. Finally, a PLC control subsystem is set up to control the system in real time, enabling the testing of heat exchange capacity for different well types, quantitative evaluation of engineering economics, and real-time calculation and cross-verification of dual-path heat transfer. This improves the well type adaptability and the accuracy of benefit calculation of this application's system.

[0014] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0016] Figure 1 This is a schematic diagram of the structure of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system of the present invention.

[0017] In the diagram, 1 is a plate heat exchanger; 2 is a screw chiller; 3 is a closed-circuit cooling tower; 4 is a second circulation pump; 5 is a fourth circulation pump; 6 is a sixth circulation pump; 7 is a basket filter; 8 is an elevated expansion tank; and 9 is a geothermal well. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0019] The multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system of this application is mainly designed for the heat exchange capacity of geothermal energy. There are various types of geothermal wells, including U-shaped wells, L-shaped wells and coaxial casing wells. Existing geothermal well heat exchange capacity testing devices have technical problems such as poor well type adaptability and inaccurate benefit calculation when testing the heat exchange capacity of different well types.

[0020] To address the aforementioned technical issues, this application provides a multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system. Its basic concept is as follows: First, the ground source subsystem, evaporation subsystem, and condensation subsystem are integrated onto a mobile platform, with automatic cooling coupled through a screw chiller and a closed-circuit cooling tower. Second, thermometers and heat meters are installed on each loop of the ground source, evaporation, and condensation subsystems to monitor the supply water temperature, return water temperature, and volumetric flow rate in real time. The temperature and volumetric flow rate collected by the thermometers and heat meters are transmitted to a PLC control subsystem. The PLC control subsystem stores heat exchange capacity testing and verification algorithms for various geothermal well types, adapting to the testing of heat exchange capacity for different well types, quantitative evaluation of engineering economics, and real-time calculation and cross-verification of dual-path heat transfer.

[0021] Based on the above basic concept, the following are different embodiments for illustration: Multi-condition adaptive testing system for the heat exchange capacity of medium-deep geothermal wells, such as Figure 1As shown, it includes: a ground-source subsystem, including a plate heat exchanger 1, a first inlet pipe, and a first outlet pipe. The first inlet pipe is connected to the primary side inlet of the plate heat exchanger 1, and the first outlet pipe is connected to the primary side outlet of the plate heat exchanger 1. A first thermometer a and a first heat meter are installed on the first inlet pipe, and a second thermometer a is installed on the first outlet pipe; an evaporation subsystem, including a screw chiller unit 2, a second inlet pipe, and a second outlet pipe. One end of the second inlet pipe is connected to the secondary side outlet of the plate heat exchanger 1, and the other end is connected to the primary side inlet of the screw chiller unit 2. A third thermometer and a third heat meter are installed on the second inlet pipe; one end of the second outlet pipe is connected to the primary side outlet of the screw chiller unit 2, and the other end is connected to the secondary side inlet of the plate heat exchanger 1. A fourth thermometer is installed on the second outlet pipe; condensation... The side subsystem includes a closed-circuit cooling tower 3, a third inlet pipe, and a third outlet pipe. One end of the third inlet pipe is connected to the secondary side outlet of the screw chiller unit 2, and the other end is connected to the inlet of the closed-circuit cooling tower 3. A fifth thermometer a and a fifth heat meter are installed on the third inlet pipe. One end of the third outlet pipe is connected to the outlet of the closed-circuit cooling tower 3, and the other end is connected to the secondary side inlet of the screw chiller unit 2. A sixth thermometer is installed on the third outlet pipe. The PLC control subsystem includes a PLC control cabinet. The signal input terminals of the PLC control cabinet are electrically connected to the first thermometer a, the first heat meter, the second thermometer a, the third thermometer, the third heat meter, the fourth thermometer, the fifth thermometer a, the fifth heat meter, and the sixth thermometer, respectively. The PLC control cabinet has a preset algorithm for testing and verifying the heat exchange capacity of each type of geothermal well.

[0022] In this embodiment, the system of this application includes a ground source side subsystem, an evaporation side subsystem, a condensation side subsystem, and a PLC control subsystem, as well as a mobile platform. The ground source side subsystem, the evaporation side subsystem, and the condensation side subsystem are integrated on the mobile platform. The mobile platform is a mobile integrated design, which integrates all test components on the mobile platform, enabling overall transportation and rapid relocation, greatly reducing the on-site installation and commissioning cycle.

[0023] Then, the free end of the first inlet pipe of this application system is connected to the outlet of the geothermal well 9, and the free end of the first outlet pipe is connected to the inlet of the geothermal well 9, so as to form a geothermal side subsystem circulation loop between the geothermal well 9 and the plate heat exchanger 1. Among them, the geothermal well 9 is the heat source starting point. The first inlet pipe is equipped with a basket filter 7, a first butterfly valve, a first thermometer a, a first pressure gauge a, and a first heat meter and other pipe accessories in sequence along the water inlet direction, for monitoring the 18℃ water supply temperature. The basket filter 7 is installed on the water supply pipe of the geothermal side circulation loop, located at the outlet of the geothermal well 9, for filtering impurities in the circulation medium and protecting the geothermal well 9 and the pump group. The second circulation pump 4 is connected back to the geothermal well 9 through the first outlet pipe. The first outlet pipe is equipped with a second circulation pump 4, a second pressure gauge a, a second check valve, a second thermometer a, a second butterfly valve and other pipe accessories in sequence along the water outlet direction, for monitoring the 8℃ return water temperature, and finally connected back to the geothermal well 9 to complete the geothermal side closed circulation.

[0024] The secondary side outlet of plate heat exchanger 1 is connected to the primary side inlet of screw chiller 2 through a second inlet pipe, and the primary side outlet of screw chiller 2 is connected to the secondary side inlet of plate heat exchanger 1 through a second outlet pipe, forming a circulation loop of the evaporation side subsystem. The second inlet pipe is equipped with a third heat meter, a third electric butterfly valve, a third thermometer, and a third pressure gauge a, etc., along the water inlet direction, to monitor the 12℃ supply water temperature. The second outlet pipe is equipped with a fourth butterfly valve, a fourth thermometer, a fourth pressure gauge a, a fourth circulation pump 5, a fourth pressure gauge b, a fourth check valve, a fourth electric butterfly valve, and a fourth pressure transmitter, etc., along the water outlet direction, to monitor the 7℃ return water temperature, forming a closed circulation on the evaporation side.

[0025] Finally, the secondary side outlet of the screw chiller unit 2 is connected to the inlet of the closed cooling tower 3 through a third inlet pipe, and the outlet of the closed cooling tower 3 is connected to the secondary side inlet of the screw chiller unit 2 through a third outlet pipe, forming a condensing side subsystem circulation loop. The third inlet pipe is equipped with a fifth pressure gauge a, a fifth thermometer a, a fifth heat meter, and a fifth butterfly valve a, among other pipe accessories, along the inlet direction, to monitor the 35℃ supply water temperature. The third outlet pipe is equipped with a sixth valve, a sixth reducer, a sixth pressure gauge a, a sixth circulation pump 6, a sixth pressure gauge b, a sixth check valve, and a sixth thermometer, among other pipe accessories, along the outlet direction, to monitor the 30℃ return water temperature, forming a closed-loop condensing side circulation.

[0026] In addition, this embodiment also includes a PLC control subsystem, which includes a PLC control cabinet. Its signal input terminals are electrically connected to the first thermometer a, the first heat meter, the second thermometer a, the third thermometer, the third heat meter, the fourth thermometer, the fifth thermometer a, the fifth heat meter, and the sixth thermometer, respectively. The first thermometer a monitors the supply water temperature of the ground source subsystem in real time, the second thermometer a monitors the return water temperature of the ground source subsystem in real time, and the first heat meter monitors the volumetric flow rate of the ground source subsystem in real time. The third thermometer monitors the supply water temperature of the evaporation subsystem in real time. The water temperature is monitored in real time by a fourth thermometer for the return water temperature of the evaporation-side subsystem and by a third heat meter for the volumetric flow rate of the evaporation-side subsystem. Similarly, the supply water temperature of the condensation-side subsystem is monitored in real time by a fifth thermometer, and the return water temperature of the condensation-side subsystem is monitored in real time by a sixth thermometer, and the volumetric flow rate of the condensation-side subsystem is monitored in real time by a fifth heat meter. This real-time data is then input into the PLC control subsystem via a signal terminal to enable testing of the heat exchange capacity of different well types, quantitative evaluation of engineering economics, and real-time calculation and cross-verification of dual-path heat transfer. This improves the well type adaptability and the accuracy of benefit calculations in this application's system.

[0027] This application provides a preferred embodiment, such as... Figure 1 As shown, a second circulation pump 4 is installed on the first outlet pipe, a fourth circulation pump 5 and a fourth electric three-way regulating valve are installed on the second outlet pipe, a fifth electric three-way shut-off valve is installed on the third inlet pipe, and a sixth circulation pump 6 and a sixth electric three-way shut-off valve are installed on the third outlet pipe. Furthermore, the control output terminals of the PLC control cabinet are electrically connected to the frequency converters of the second circulation pump 4, the fourth circulation pump 5, and the sixth circulation pump 6, as well as the fourth electric three-way regulating valve, the fifth electric three-way shut-off valve, and the sixth electric three-way shut-off valve. In this embodiment, the connection relationship between the PLC control subsystem and the pumps and valves on each pipeline is further defined. Specifically, the second circulating pump 4, the fourth circulating pump 5, and the sixth circulating pump 6 are respectively connected to the control output terminal of the PLC control cabinet through a frequency converter. The PLC control cabinet outputs a speed regulation signal to achieve continuous regulation of the flow rate of each pipeline. The fourth electric three-way regulating valve on the second outlet pipeline in the evaporation side subsystem is connected to the control output terminal of the PLC control cabinet to receive continuous regulation signals. The fifth electric three-way shut-off valve and the sixth electric three-way shut-off valve in the condensation side subsystem are connected to the control output terminal of the PLC control cabinet to achieve reliable switching between the main pipeline and the bypass, which is beneficial to the automatic control of the system of this application.

[0028] This application provides a preferred embodiment, wherein the PLC control subsystem further includes a human-machine interface, which is connected to the PLC control cabinet; the output terminal of the PLC control cabinet is connected to the control circuit of the closed cooling tower 3, and the PLC control cabinet is bidirectionally connected to the communication interface of the screw chiller unit 2. In this embodiment, the screw chiller unit 2 is bidirectionally connected to the PLC control cabinet via a communication bus; the fan drive circuit of the closed cooling tower 3 is connected to the switch input channel of the PLC control cabinet, and the start / stop and frequency conversion speed regulation of the fan are controlled by the program; the human-machine interface is a touch screen host computer, and the PLC control subsystem has built-in storage of well-type heat exchange correction sub-algorithm, multi-condition programmed test control sub-algorithm, engineering economic quantitative evaluation sub-algorithm, and dual-channel heat real-time calculation and cross-verification sub-algorithm. The PLC control cabinet is connected to the human-machine interface, and the operator can select the well type of the geothermal well 9 on the human-machine interface and start the preset programmed test process with one click, thereby realizing test mode selection, parameter distribution, data display, automatic analysis, and report output.

[0029] This application provides a preferred embodiment, wherein the geothermal well type includes U-shaped wells, L-shaped wells, and coaxial casing wells. In this embodiment, the geothermal well 9 is further defined as having three types: U-shaped wells, L-shaped wells, and coaxial casing wells. The structure of the U-shaped well is as follows: two PE pipes are lowered into a vertical shaft, connected at the bottom by an elbow to form a U-shaped loop; the pipes are vertically buried throughout the borehole, which is backfilled with heat-conducting mortar. The structure of the L-shaped well is as follows: the upper section is a vertical shaft, which turns directionally after reaching the target depth, extending into a horizontal heat exchange section, with the overall shape presenting an "L" structure. The structure of the coaxial casing well is as follows: two pipes of unequal diameter are coaxially arranged in the vertical shaft, with the medium flowing downwards from the interlayer between the two pipes and flowing upwards back through the central inner pipe; reverse flow is also possible.

[0030] This application provides a preferred embodiment, wherein the heat exchange capacity testing and verification algorithm for each type of geothermal well includes: a well-type heat exchange correction sub-algorithm, used to introduce corresponding correction coefficients for the U-shaped well, the L-shaped well, and the coaxial casing well to correct the original heat exchange; a multi-condition programmed test control sub-algorithm, which incorporates three types of well-type test processes: the U-shaped well executes a stepped variable flow steady-state test process, the L-shaped well executes a single-branch and multi-branch parallel comparison test process, and the coaxial casing well executes a high-low temperature cyclic hot-cold alternation test process; and an engineering economics quantitative evaluation sub-algorithm, which sums the total construction cost of all geothermal wells, the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, the cost of the outdoor power grid, and the cost of the machine room construction to obtain the static total investment of the project; and divides the static total investment of the project by the preset annual net savings in geothermal system operating costs to obtain the static... The system employs a dual-path real-time heat calculation and cross-validation algorithm to simultaneously collect temperature and flow data from each pipeline in the ground source subsystem and the condensation subsystem. Based on the temperature data, flow data, and preset formulas, it calculates in real-time the total heat released by the geothermal rock and soil to the circulating medium per unit time and the total heat removed from the test loop by the cooling system per unit time. The total heat released by the geothermal rock and soil to the circulating medium per unit time is accumulated to obtain the total heat exchange over a cumulative period. The total heat removed from the test loop by the cooling system per unit time is accumulated to obtain the total cooling capacity over a cumulative period. When the system is in a thermal steady state, the system calculates the instantaneous relative heat error and the cumulative relative heat error over a cumulative period on both sides of the ground source subsystem and the condensation subsystem, and determines whether the data of the instantaneous relative heat error and the cumulative relative heat error over a cumulative period are qualified based on preset thresholds.

[0031] In this embodiment, a sub-algorithm for heat exchange correction based on well type eliminates test deviations caused by different well structures, and a standardized and automated test process adapted to various well types unifies the test conditions. Real-time heat calculation via the ground source subsystem and the condensation subsystem, along with dual-layer error verification of instantaneous relative heat error and cumulative time-period relative heat error, enables autonomous identification and correction of test data. Simultaneously, a built-in sub-algorithm for quantitative evaluation of engineering economics calculates the project's static total investment and static investment payback period based on accurate measured heat exchange data. The collaborative work of multiple algorithms enables automated testing, data cross-validation, and quantitative evaluation of engineering economics for geothermal wells of different types, effectively improving the accuracy of geothermal well heat exchange capacity testing and the reliability of engineering evaluation. Furthermore, it enhances the adaptability to different well types.

[0032] This application provides a preferred embodiment, wherein the well-type heat transfer correction sub-algorithm is used to introduce corresponding correction coefficients for the U-shaped well, the L-shaped well, and the coaxial casing well, respectively, to correct the original heat transfer; including: according to a first preset formula: Q=ρ×V×Cp Calculate the original heat transfer Q using ×ΔT, where ρ is the density of water in kg / m³. 3 V represents the volumetric flow rate of water, in cubic meters per second (m³). 3 / s;C p ΔT is the specific heat of water at constant pressure, expressed in kJ / (kg×℃); ΔT is the temperature difference between the inlet and outlet water temperatures of the system, expressed in ℃; and the friction loss correction factor is based on the preset U-shaped well depth. And the second preset formula: The heat transfer after correction of the U-shaped well was calculated. Based on the pre-set L-shaped well, the lateral heat transfer correction coefficient of the horizontal section of the formation is increased. And the third preset formula: The corrected heat transfer of the L-shaped well was calculated. Based on the preset radial heat conduction loss correction coefficient of the inner and outer pipes of the coaxial casing well. And the fourth preset formula: The corrected heat transfer of the coaxial casing well was calculated. .

[0033] In this embodiment, firstly, the system monitors the supply water temperature, return water temperature, and volumetric flow rate of each subsystem in real time using thermometers and heat meters arranged on each pipeline. Based on the monitored supply water temperature data, return water temperature data, volumetric flow rate data, and a first preset formula, the system calculates the original heat exchange capacity, which is also the heat exchange capacity of the medium-deep geothermal well, in kW. Then, the system calculates the corrected heat exchange capacity of the U-shaped well based on a preset well depth friction loss correction coefficient; the system calculates the corrected heat exchange capacity of the L-shaped well based on an added horizontal section formation lateral heat exchange correction coefficient; and the system calculates the corrected heat exchange capacity of the coaxial casing well based on the radial heat conduction loss correction coefficient of the inner and outer pipes. This effectively offsets the data deviation caused by the structural differences of the well body, ensuring that the heat exchange capacity calculation results of different well types are comparable laterally.

[0034] This application provides a preferred embodiment, wherein the stepped variable flow steady-state test process involves setting multiple circulating flow rates step by step, maintaining the flow rate at each level until thermal steady state and collecting heat transfer data to obtain the steady-state heat transfer performance parameters of the U-shaped well under different flow rates; the single-branch and multi-branch parallel comparison test process involves conducting independent tests on each branch to obtain independent test data, and conducting joint tests on multiple branches in parallel to obtain joint test data, and then comparing the independent test data and the joint test data to determine the degree of formation thermal interference and pipeline heat transfer balance between branches; the high and low temperature cyclic hot and cold alternation test process automatically alternates to simulate winter heat extraction and summer heat exhaust conditions, and collects bidirectional steady-state heat transfer data for heat extraction and heat exhaust respectively to evaluate the radial heat conduction loss of the wellbore.

[0035] In this embodiment, the specific methods for incorporating three types of well test processes into the multi-condition programmed test control sub-algorithm are further defined. For U-shaped wells, a stepped variable flow steady-state test process is adopted. This process involves: the system presets multiple circulating flow rates, gradually adjusting from low to high flow rates; after adjusting to the target flow rate, continuously monitoring the temperature difference and flow fluctuation of the supply and return water on the ground source side; and after meeting the thermal steady-state judgment conditions, conducting steady-state data acquisition and dual-path heat cross-verification. After completing one flow rate test, the system automatically switches to the next flow rate level until all gradient flow rate tests are completed, obtaining the steady-state heat transfer performance parameters of the U-shaped well under different flow rate conditions. For L-shaped wells, a single-branch and multi-branch parallel comparison test process is adopted. This process involves: first, controlling the valves of each branch to open and close sequentially, then conducting independent steady-state tests on each horizontal branch pipeline, recording the results of each branch individually. The heat exchange capacity was assessed by opening all branch pipelines and then operating them in parallel to test the total heat exchange capacity. The cumulative value of the individual test data of each branch was compared with the combined test data of the multiple branches to evaluate the degree of formation thermal interference between horizontal branches and the heat exchange balance of the pipeline. The coaxial casing well adopted a high and low temperature cycle hot and cold alternation test process. The high and low temperature cycle hot and cold alternation test process is as follows: the program automatically simulates the formation heat extraction condition in winter and the formation heat exhaust condition in summer. Under the heat extraction condition, the geothermal well circulating medium absorbs heat from the rock and soil, and the cooling circuit continuously removes heat and conducts steady-state heat exchange test. After the condition is smoothly switched, the heat exhaust condition is entered, heat is released to the formation and heat exhaust heat exchange data is collected. The system automatically completes multiple rounds of hot and cold alternation cycle test, simultaneously obtains the bidirectional heat exchange index of heat extraction and heat exhaust, quantifies the radial heat conduction loss of the inner and outer pipes, and can simulate the bidirectional operation condition of the project throughout the year in winter and summer. Therefore, in this embodiment, the automated testing processes specific to the three well types can be started by the operator simply selecting the test process to be used on the human-machine interface when needed. This eliminates the need for manual customization of operating parameters, significantly reducing the on-site operation threshold. At the same time, the system of this application can realize the automatic collection, storage, analysis and curve plotting of test data, support the programmed automatic testing of various operating conditions, and quickly generate test reports. This is conducive to improving the automation level of the system of this application, reducing operational requirements, and has broad application prospects.

[0036] In one example, under winter outdoor temperatures below -5℃, the test is conducted under low flow and low heat exchange load conditions in the U-shaped well. The screw chiller unit 2 alone can meet the return water cooling requirements, eliminating the need for the closed-circuit cooling tower 3. The closed-circuit cooling tower 3 is then fully bypassed. The operation procedure is as follows: The system is powered on and initialized. The PLC control subsystem reads the temperature difference between the supply and return water on the ground source side, the real-time heat exchange load, and the outdoor ambient temperature sensor values. The operator selects the "Winter Low Temperature Low Load Test" mode on the human-machine interface. The PLC control subsystem issues a bypass switching command, and the electric three-way shut-off valve receives the electrical signal. The system automatically reverses direction, disconnecting the main circulation pipeline between the screw chiller unit 2 and the closed cooling tower 3, and opening the bypass pipeline; the sixth circulation pump 6 continues to run, and the circulating medium on the condensate side no longer flows through the closed cooling tower 3, but only circulates in a closed loop between the screw chiller unit 2 and the bypass pipeline; the system automatically adjusts the load power of the screw chiller unit 2 and stably controls the return water temperature on the ground source side to the set test value; after the test, the operating load of the screw chiller unit 2 is reduced first, then a valve reset command is issued, the electric three-way shut-off valve switches back to the main line, restoring the closed cooling tower 3 to the series operation state, and finally the equipment is shut down. During this process, the following points should be noted: ① Switching the electric three-way shut-off valve must be done in the automatic control mode of the PLC control subsystem in this application system. It is forbidden to manually force the valve body on site to prevent damage to the sealing structure inside the valve body; ② After each working condition switch, the system automatically records the valve status, pipeline pressure, and temperature data, and stores them in the test report simultaneously for easy data traceability later; ③ Air vents are installed at both ends of the bypass pipeline. Before each seasonal change or working condition switch, the air accumulated inside the bypass pipeline must be manually vented to prevent air resistance from forming during circulation; ④ The actuator signal of the electric three-way shut-off valve should be checked regularly. If the valve switching is not in place or there is leakage, it will lead to a decrease in the temperature control accuracy of the cooling system and affect the accuracy of heat exchange test results for different well types; ⑤ The valve switching logic is linked with the dual cooling coupling control program. The switching action takes priority over the power adjustment of the screw chiller unit to avoid over-temperature alarms caused by loading the unit first and then switching the pipeline.

[0037] This application provides a preferred embodiment, wherein the total static investment of the project is obtained by summing the total construction cost of all geothermal wells, the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, the cost of the outdoor power grid, and the cost of the machine room civil engineering; including: according to the fifth preset formula: Calculate the total construction cost of all geothermal wells. ;in, Cost of drilling and backfilling for a single well; The cost of the downhole heat exchange pipeline for the U-shaped well, L-shaped well, or coaxial casing well; N is the total number of geothermal wells.

[0038] According to the sixth preset formula: Calculate the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system. ;in, Cost of testing hardware; Cost of circulating pump unit; Costs for manifolds, valves, and piping; Costs for the PLC control subsystem.

[0039] Based on the total construction cost of all the aforementioned geothermal wells The total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system Cost of outdoor connection pipeline Computer room civil engineering cost And the seventh preset formula: Calculate the static total investment of the project .

[0040] The step of obtaining the static investment payback period by dividing the total static investment of the project by the preset annual net savings in geothermal system operating costs includes: according to the eighth preset formula: Calculate the amount of coal saved annually after adopting a geothermal system. ;in, The total heat exchange capacity of the geothermal system for heating throughout the year, in KW; To convert the cumulative total heat exchange power into the total annual heat output using a conversion factor, ; The standard calorific value is taken as 29300 kJ / kg; The efficiency of a traditional coal-fired boiler is taken as 0.75.

[0041] Based on the amount of coal saved annually after adopting the geothermal system And the ninth preset formula: Calculate the net annual operating cost savings of the pre-designed geothermal system. ;in, This refers to the market price per unit of standard coal. The total annual electricity cost for the geothermal circulation pump and testing system.

[0042] Based on the project's static total investment and the annual net savings in operating costs of the pre-set geothermal system And the tenth preset formula: Calculate the static payback period .

[0043] In this embodiment, a quantitative evaluation sub-algorithm for engineering economics is further defined. This algorithm first calculates the total construction cost of all geothermal wells based on the drilling and backfilling costs of a single well, the cost of the downhole heat exchange pipeline for a single well, and the total number of geothermal wells. Then, it accumulates the costs of testing hardware, circulating pump sets, manifolds and valves, PLC control subsystems, outdoor connection networks, and civil engineering for the machine room to obtain the total static investment of the project. Based on the total annual geothermal heat supply, it calculates the annual standard coal savings under the condition of replacing a coal-fired boiler with the system, i.e., the quality of coal saved annually after adopting the geothermal system. Combining the coal price per unit and the annual electricity cost of the system, it obtains the pre-set net annual operating cost savings of the geothermal system. Finally, it calculates the static investment payback period by combining the total static investment of the project with the pre-set net annual operating cost savings of the geothermal system, completing the investment estimation and economic evaluation of heat source matching and equipment selection.

[0044] This application provides a preferred embodiment in which the dual-path heat real-time calculation and cross-verification sub-algorithm synchronously collects temperature and flow data from each pipeline of the ground source subsystem and the condensation subsystem through the PLC control subsystem. Based on the temperature data, the flow data, and a preset formula, it calculates in real time the total heat released by the geothermal rock and soil to the circulating medium per unit time and the total heat removed from the test loop by the cooling system per unit time. It then accumulates the total heat released by the geothermal rock and soil to the circulating medium per unit time to obtain the total heat exchange over a cumulative period; and accumulates the total heat removed from the test loop by the cooling system per unit time to obtain the total cooling capacity over a cumulative period. When the system is in a thermal steady state, it calculates the instantaneous relative heat error and the cumulative relative heat error over a cumulative period on both sides of the ground source subsystem and the condensation subsystem, and judges whether the data of the instantaneous relative heat error and the cumulative relative heat error over a cumulative period are qualified according to a preset threshold. This includes: synchronously collecting the water supply temperature of the ground source subsystem through the first thermometer a, the second thermometer a, and the first heat meter. Return water temperature and source-side volumetric flow ; and based on the collected water supply temperature The return water temperature The source-side volumetric flow rate And the eleventh preset formula: Calculate the total heat released by the geothermal rock mass to the circulating medium per unit time. ;in, This is the density of water, expressed in kg / m³. 3 The value is taken as 1000 kg / m 3 ; This is the isobaric specific heat of water, expressed in kJ / (kg×℃), and is taken as 4.187 kJ / (kg∙℃).

[0045] The water supply temperature of the condenser subsystem is simultaneously collected by the fifth thermometer a, the sixth thermometer, and the fifth heat meter. Return water temperature and condenser side volumetric flow rate ; and based on the collected water supply temperature The return water temperature The condensation side volumetric flow rate And the twelfth preset formula: Calculate the total heat removed from the test loop by the cooling system per unit time. ;in, This is the density of water, expressed in kg / m³. 3 The value is taken as 1000 kg / m 3 ; This is the isobaric specific heat of water, expressed in kJ / (kg×℃), and is taken as 4.187 kJ / (kg∙℃).

[0046] Based on the total heat released by the geothermal rock and soil mass to the circulating medium per unit time And the thirteenth preset formula: Calculate the total heat exchange over the cumulative period ;in, The initial time, This is a cumulative time period.

[0047] Based on the total heat removed from the test circuit by the cooling system per unit time And the fourteenth preset formula: Calculate the total cooling load over the cumulative period ;in, The initial time, This is a cumulative time period.

[0048] When the system is in a thermal steady state, the total heat released by the geothermal rock and soil to the circulating medium per unit time is as described. and the total heat removed from the test loop by the cooling system per unit time. And the fifteenth preset formula: Calculation of relative error of instantaneous heat .

[0049] Based on the total heat exchange during the cumulative time period and the total cooling capacity during the cumulative period And the sixteenth preset formula: Calculating the relative error of cumulative heat over a period of time .

[0050] Preset first threshold Second threshold ,and .

[0051] The relative error of instantaneous heat With the first threshold The second threshold For comparison: when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. Qualified; when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. If a slight deviation is found, the human-machine interface will display a prompt to check the instruments and pipeline insulation; when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. If the system fails, the human-computer interaction interface will display the abnormal time period and the cause of the failure.

[0052] The relative error of the cumulative heat over the period With the first threshold The second threshold For comparison: when At that time, the total heat exchange during the cumulative period Qualified; when At that time, the total heat exchange during the cumulative period If a slight deviation is found, the human-machine interface will display a prompt to check the instruments and pipeline insulation; when At that time, the total heat exchange during the cumulative period If the system fails, the human-computer interaction interface will display the abnormal time period and the cause of the failure.

[0053] In this embodiment, the total heat released by the geothermal rock and soil to the circulating medium per unit time is obtained based on the real-time monitoring of the supply water temperature of the geothermal side subsystem by the first thermometer a, the real-time monitoring of the return water temperature of the geothermal side subsystem by the second thermometer a, and the real-time monitoring of the volumetric flow rate of the geothermal side subsystem by the first heat meter. Based on the real-time monitoring of the supply water temperature of the condenser-side subsystem by the fifth thermometer a, the real-time monitoring of the return water temperature of the condenser-side subsystem by the sixth thermometer, and the real-time monitoring of the volumetric flow rate of the condenser-side subsystem by the fifth heat meter, the total heat removed from the test loop by the cooling system per unit time is obtained. Then, based on the total heat released by the geothermal rock mass to the circulating medium per unit time... and the total heat removed from the test loop by the cooling system per unit time The total heat exchanged during the cumulative time period is obtained by integrating the components separately. Total cooling capacity over the cumulative period Based on the above calculations, the relative error of instantaneous heat is then calculated. Relative error of cumulative heat over time period Two thresholds are preset simultaneously, namely the first threshold... Second threshold ,and Finally, the relative error of instantaneous heat will be calculated. Relative error of cumulative heat over time period The system compares the instantaneous relative heat error with two thresholds to determine whether the relative heat error over a cumulative period is within acceptable, has a slight deviation, or is in failure status. This serves as a reminder of the system's condition and helps improve its reliability and stability. In one example, the first threshold is... The second threshold is The relative error of the instantaneous heat Compare with the first threshold and the second threshold: when At that time, the data was qualified; when At times, the data may have slight deviations; when When the data becomes invalid, the relative error of the accumulated heat over the specified period will be calculated. The comparison with the first threshold and the second threshold is consistent with the above, and will not be repeated here; the two verifications help to improve the accuracy and reliability of the test results of the system in this application.

[0054] In addition, the rule for judging thermal steady state in this embodiment is: continuously monitor the temperature difference and flow fluctuation of the supply and return water on the ground source side. When the flow fluctuation is ≤±2% and the temperature difference fluctuation is ≤±0.3℃ within 15 minutes, it is determined that the stable test condition has been entered and the heat cross-verification is initiated.

[0055] Compared with existing testing methods that only collect single-path parameters from the geothermal well side, this application's system simultaneously configures heat meters and thermometers at key nodes on both the source and condensation sides. It also uses a unified heat calculation formula to calculate in real-time the total heat released by the geothermal rock and soil to the circulating medium per unit time. and the total heat removed from the test loop by the cooling system per unit time Simultaneously, this application's system employs synchronous acquisition of two channels of flow and temperature data, utilizing instantaneous relative heat error. Relative error of cumulative heat over time period A dual-validation mechanism is used to perform cross-validation, and a first threshold is set. Second threshold Two error thresholds distinguish between qualified data, slight deviations, and failed data. At the same time, the heat loss of the pipeline is quantified and the data is corrected based on the heat difference between the hot and cold sides. The two data sources complement each other and cross-verify each other, which greatly improves the accuracy and reliability of heat exchange test results under different well types and all operating conditions.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The various embodiments in this specification are described in a related manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments. For related parts, please refer to the description of the method embodiment.

[0058] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, characterized in that, include: The ground source subsystem includes a plate heat exchanger (1), a first inlet pipe and a first outlet pipe. The first inlet pipe is connected to the primary side inlet of the plate heat exchanger (1), and the first outlet pipe is connected to the primary side outlet of the plate heat exchanger (1). A first thermometer a and a first heat meter are installed on the first inlet pipe, and a second thermometer a is installed on the first outlet pipe. The evaporation-side subsystem includes a screw chiller unit (2), a second inlet pipe, and a second outlet pipe. One end of the second inlet pipe is connected to the secondary outlet of the plate heat exchanger (1), and the other end is connected to the primary inlet of the screw chiller unit (2). A third thermometer and a third heat meter are installed on the second inlet pipe. One end of the second outlet pipe is connected to the primary outlet of the screw chiller unit (2), and the other end is connected to the secondary inlet of the plate heat exchanger (1). A fourth thermometer is installed on the second outlet pipe. The condensing subsystem includes a closed cooling tower (3), a third inlet pipe, and a third outlet pipe. One end of the third inlet pipe is connected to the secondary outlet of the screw chiller (2), and the other end of the third inlet pipe is connected to the inlet of the closed cooling tower (3). A fifth thermometer a and a fifth heat meter are installed on the third inlet pipe. One end of the third outlet pipe is connected to the outlet of the closed cooling tower (3), and the other end of the third outlet pipe is connected to the secondary inlet of the screw chiller (2). A sixth thermometer is installed on the third outlet pipe. The PLC control subsystem includes a PLC control cabinet. The signal input terminals of the PLC control cabinet are electrically connected to the first thermometer a, the first heat meter, the second thermometer a, the third thermometer, the third heat meter, the fourth thermometer, the fifth thermometer a, the fifth heat meter, and the sixth thermometer, respectively. The PLC control cabinet is pre-programmed with a test and verification algorithm for the heat exchange capacity of each type of geothermal well.

2. The system according to claim 1, characterized in that, A second circulation pump (4) is installed on the first water outlet pipe, a fourth circulation pump (5) and a fourth electric three-way regulating valve are installed on the second water outlet pipe, a fifth electric three-way shut-off valve is installed on the third water inlet pipe, and a sixth circulation pump (6) and a sixth electric three-way shut-off valve are installed on the third water outlet pipe.

3. The system according to claim 2, characterized in that, The control output terminal of the PLC control cabinet is electrically connected to the frequency conversion drive device of the second circulating pump (4), the fourth circulating pump (5) and the sixth circulating pump (6), as well as the fourth electric three-way regulating valve, the fifth electric three-way shut-off valve and the sixth electric three-way shut-off valve.

4. The system according to claim 3, characterized in that, The PLC control subsystem also includes a human-machine interface, which is connected to the PLC control cabinet; the output end of the PLC control cabinet is connected to the control loop of the closed cooling tower (3), and the PLC control cabinet is bidirectionally connected to the communication interface of the screw chiller unit (2).

5. The system according to claim 4, characterized in that, The geothermal wells include U-shaped wells, L-shaped wells, and coaxial casing wells.

6. The system according to claim 5, characterized in that, The heat exchange capacity testing and verification algorithm for each type of geothermal well includes: The well-type heat exchange correction sub-algorithm is used to introduce corresponding correction coefficients for the U-shaped well, the L-shaped well, and the coaxial casing well to correct the original heat exchange. The multi-condition programmed test control sub-algorithm has three built-in well type test processes: the U-shaped well executes a stepped variable flow steady-state test process, the L-shaped well executes a single-branch and multi-branch parallel comparison test process, and the coaxial casing well executes a high and low temperature cycle hot and cold alternation test process. The sub-algorithm for quantitative evaluation of engineering economics sums the total construction cost of all geothermal wells, the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, the cost of the outdoor power grid, and the cost of the machine room civil engineering to obtain the static total investment of the project; and divides the static total investment of the project by the preset annual net savings in the operating cost of the geothermal system to obtain the static investment payback period. The dual-path real-time heat calculation and cross-validation sub-algorithm synchronously collects temperature and flow data from each pipeline of the ground source subsystem and the condensation subsystem. Based on the temperature data, the flow data, and preset formulas, it calculates in real time the total heat released by the geothermal rock and soil to the circulating medium per unit time and the total heat removed from the test loop by the cooling system per unit time. The total heat released by the geothermal rock and soil to the circulating medium per unit time is accumulated to obtain the total heat exchange over a cumulative period. The total heat removed from the test loop by the cooling system per unit time is accumulated to obtain the total cooling capacity over a cumulative period. When the system is in a thermal steady state, it calculates the instantaneous relative heat error and the cumulative relative heat error over a cumulative period on both sides of the ground source subsystem and the condensation subsystem, and judges whether the data of the instantaneous relative heat error and the cumulative relative heat error over a cumulative period are qualified according to preset thresholds.

7. The system according to claim 6, characterized in that, The sub-algorithm for well-type heat exchange correction is used to introduce corresponding correction coefficients for the U-shaped well, the L-shaped well, and the coaxial casing well, respectively, to correct the original heat exchange; including: According to the first preset formula: Q=ρ×V×C p Calculate the original heat transfer Q using ×ΔT, where ρ is the density of water in kg / m³. 3 V represents the volumetric flow rate of water, in cubic meters per second (m³). 3 / s;C p ΔT is the specific heat of water at constant pressure, expressed in kJ / (kg×℃); ΔT is the temperature difference between the inlet and outlet water temperatures of the system, expressed in ℃. Based on the preset well depth friction heat loss correction factor for U-shaped wells And the second preset formula: The heat transfer after correction of the U-shaped well was calculated. ; Based on the pre-set L-shaped well, the horizontal section formation lateral heat transfer correction coefficient is increased. And the third preset formula: The corrected heat transfer of the L-shaped well was calculated. ; Based on the preset radial heat conduction loss correction coefficient of the inner and outer pipes of the coaxial casing well. And the fourth preset formula: The corrected heat transfer of the coaxial casing well was calculated. .

8. The system according to claim 6, characterized in that, The stepped variable flow steady-state test process involves setting multiple circulating flow rates step by step, maintaining each flow rate until thermal steady state and collecting heat transfer data to obtain the steady-state heat transfer performance parameters of the U-shaped well under different flow rates. The single-branch and multi-branch parallel comparison test process involves conducting independent tests on each branch to obtain independent test data, conducting joint tests on multiple branches in parallel to obtain joint test data, and then comparing the cumulative value of each independent test data with the joint test data to determine the degree of ground thermal interference between branches and the heat exchange balance of the pipeline. The high and low temperature cyclic heating and cooling alternation test process automatically alternates to simulate winter heat extraction and summer heat exhaust conditions, and collects bidirectional steady-state heat exchange data for heat extraction and heat exhaust to evaluate the radial heat conduction loss of the wellbore.

9. The system according to claim 6, characterized in that, The total static investment of the project is obtained by summing the total construction cost of all geothermal wells, the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system, the cost of the outdoor power grid, and the cost of the machine room civil engineering; including: According to the fifth preset formula: Calculate the total construction cost of all geothermal wells. ;in, Cost of drilling and backfilling for a single well; The cost of the downhole heat exchange pipeline for the U-shaped well, L-shaped well, or coaxial casing well; N is the total number of geothermal wells; According to the sixth preset formula: Calculate the total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system. ;in, Cost of testing hardware; Cost of circulating pump unit; Costs for manifolds, valves, and piping; Cost of the PLC control subsystem; Based on the total construction cost of all the aforementioned geothermal wells The total investment of the multi-condition adaptive medium-deep geothermal well heat exchange capacity testing system Cost of outdoor connection pipeline Computer room civil engineering cost And the seventh preset formula: Calculate the static total investment of the project ; The static investment payback period is obtained by dividing the total static investment of the project by the pre-set net savings in the annual operating cost of the geothermal system; including: According to the eighth preset formula: Calculate the amount of coal saved annually after adopting a geothermal system. ;in, The total heat exchange capacity of the geothermal system for heating throughout the year, expressed in kW; To convert the cumulative total heat exchange power into the total annual heat output using a conversion factor, ; The standard calorific value is taken as 29300 kJ / kg; The efficiency of a traditional coal-fired boiler is taken as 0.

75. Based on the amount of coal saved annually after adopting the geothermal system And the ninth preset formula: Calculate the net annual operating cost savings of the pre-designed geothermal system. ;in, This refers to the market price per unit of standard coal. The total annual electricity cost for the geothermal circulation pump and testing system; Based on the project's static total investment and the annual net savings in operating costs of the pre-set geothermal system And the tenth preset formula: Calculate the static payback period .

10. The system according to claim 6, characterized in that, The dual-path heat real-time calculation and cross-verification sub-algorithm synchronously collects temperature and flow data on each pipeline of the ground source subsystem and the condensation subsystem through the PLC control subsystem. Based on the temperature data, the flow data and the preset formula, it calculates in real time the total heat released by the geothermal rock and soil to the circulating medium per unit time and the total heat taken away by the cooling system from the test loop per unit time. The total heat released by the geothermal rock and soil to the circulating medium per unit time is accumulated to obtain the total heat exchange over the cumulative period; the total heat removed from the test loop by the cooling system per unit time is accumulated to obtain the total cooling capacity over the cumulative period; when the system is in a thermal steady state, the instantaneous relative heat error and the cumulative relative heat error over the cumulative period are calculated on both sides of the ground source subsystem and the condensation subsystem, and the data of the instantaneous relative heat error and the cumulative relative heat error over the cumulative period are judged to be qualified according to a preset threshold; including: The water supply temperature of the ground source subsystem is simultaneously collected by the first thermometer a, the second thermometer a, and the first heat meter. Return water temperature and source-side volumetric flow ; and based on the collected water supply temperature The return water temperature The source-side volumetric flow rate And the eleventh preset formula: Calculate the total heat released by the geothermal rock mass to the circulating medium per unit time. ;in, This is the density of water, expressed in kg / m³. 3 The value is taken as 1000 kg / m 3 ; This is the specific heat of water at constant pressure, expressed in kJ / (kg×℃), and is taken as 4.187 kJ / (kg∙℃). The water supply temperature of the condenser subsystem is simultaneously collected by the fifth thermometer a, the sixth thermometer, and the fifth heat meter. Return water temperature and condenser side volumetric flow rate ; and based on the collected water supply temperature The return water temperature The condensation side volumetric flow rate And the twelfth preset formula: Calculate the total heat removed from the test loop by the cooling system per unit time. ;in, This is the density of water, expressed in kg / m³. 3 The value is taken as 1000 kg / m 3 ; This is the specific heat of water at constant pressure, expressed in kJ / (kg×℃), and is taken as 4.187 kJ / (kg∙℃). Based on the total heat released by the geothermal rock and soil mass to the circulating medium per unit time And the thirteenth preset formula: Calculate the total heat exchange over the cumulative period ;in, The initial time, For cumulative time periods; Based on the total heat removed from the test circuit by the cooling system per unit time And the fourteenth preset formula: Calculate the total cooling load over the cumulative period ;in, The initial time, For cumulative time periods; When the system is in a thermal steady state, the total heat released by the geothermal rock and soil to the circulating medium per unit time is as described. and the total heat removed from the test loop by the cooling system per unit time. And the fifteenth preset formula: Calculation of relative error of instantaneous heat ; Based on the total heat exchange during the cumulative time period and the total cooling capacity during the cumulative period And the sixteenth preset formula: Calculating the relative error of cumulative heat over a period of time ; Preset first threshold Second threshold ,and ; The relative error of instantaneous heat With the first threshold The second threshold For comparison: when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. qualified; when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. If there is a slight deviation, the human-machine interface will display a prompt to check the instruments and pipeline insulation. when At that time, the total heat released by the geothermal rock and soil mass to the circulating medium per unit time. If the system fails, the human-computer interaction interface will display the abnormal time period and the cause of the failure. The relative error of the cumulative heat over the period With the first threshold The second threshold For comparison: when At that time, the total heat exchange during the cumulative period qualified; when At that time, the total heat exchange during the cumulative period If there is a slight deviation, the human-machine interface will display a prompt to check the instruments and pipeline insulation. when At that time, the total heat exchange during the cumulative period If the system fails, the human-computer interaction interface will display the abnormal time period and the cause of the failure.

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