A coaxial sleeve type ground heat exchanger, a ground source heat pump system and a regulation method thereof

Abstract

The application discloses a coaxial sleeve type ground buried pipe, a ground source heat pump system and a regulation and control method thereof, belongs to the technical field of ground source heat utilization, and can solve the problem of low operation energy efficiency of an existing ground source heat pump system. The ground buried pipe comprises a coaxially sleeved inner pipe and outer pipe, an annular cavity is formed between the inner pipe and the outer pipe, the top end of the annular cavity is communicated with the evaporator outlet of a heat pump unit through an inlet pipe, the top end of the inner pipe is communicated with the evaporator inlet of the heat pump unit through an outlet pipe, the bottom end of the inner pipe is communicated with the annular cavity through a water suction pipe, a first electromagnetic valve is arranged at one end of the inlet pipe connected with the evaporator outlet, a second electromagnetic valve is arranged at one end of the outlet pipe connected with the evaporator inlet, a circulating pipe is communicated with the inlet pipe and the outlet pipe at two ends, a third electromagnetic valve is arranged on the circulating pipe, a heat exchange medium can flow to fill the inner pipe, the annular cavity, the inlet pipe, the outlet pipe and the circulating pipe, and a circulating pump is arranged on the circulating pipe. The application is used for collecting ground source heat.

Description

Technical Field

[0001] This invention relates to a coaxial sleeve-type buried pipe, a ground source heat pump system and its control method, belonging to the field of ground source heat utilization technology. Background Technology

[0002] Utilizing ground source heat pump systems to extract medium-deep geothermal heat and supply it to the target population has become a clean, efficient, and low-carbon medium- and low-temperature heating method. Ground source heat pump systems typically employ a network of buried pipes consisting of multiple coaxial sheathed underground pipes to extract low-grade heat from the soil and rock, and then consume a small amount of high-grade energy (such as electricity) through the heat pump unit to achieve heating.

[0003] The coaxial sleeve-type buried pipe consists of an outer pipe and an inner pipe that are coaxially fitted together. The outer pipe is buried in a medium-deep borehole. During operation, a fluid heat exchange medium flows from the heat exchange device of the heat pump unit into the annular cavity between the outer and inner pipes. As the heat exchange medium flows downward in the annular cavity, it exchanges heat with the surrounding rock strata and heats up. The heated heat exchange medium then flows from the bottom of the annular cavity into the inner pipe, and through the inner pipe into the heat exchange device of the heat pump unit for further heat exchange, forming a closed heat extraction cycle. The coaxial sleeve-type buried pipe is buried at a depth of 1000m to 3500m, extracts a high-temperature heat source, and occupies a small area. Furthermore, since the coaxial sleeve-type buried pipe mainly relies on the thermal conductivity of the rock and soil to obtain heat, it can extract heat without extracting water, thus effectively protecting groundwater resources.

[0004] However, existing ground source heat pump systems still have the following drawbacks:

[0005] 1) During the non-heating season, the heat extraction cycle stops, and the buried pipe network mainly relies on the natural temperature difference between the radially distal strata and the strata in the buried area to maintain the heat supply to the strata in order to restore the heat of the strata. However, this heat transfer method has low heat transfer efficiency and dispersed heat transfer direction, resulting in poor heat restoration effect and easy heat attenuation in the buried area, which affects the operating energy efficiency of the ground source heat pump system.

[0006] 2) The heat exchange characteristics of different buried pipes in the buried pipe group are different, and the geological conditions and stratum temperature fields of their burial locations are also different. The existing ground source heat pump system does not take into account the above differences between different buried pipes and adopts the same operation mode for all buried pipes. As a result, the heat of some buried pipe locations cannot be fully utilized or heat attenuation occurs, which reduces the operating energy efficiency of the ground source heat pump system. Summary of the Invention

[0007] This invention provides a coaxial sleeve-type buried pipe, a ground source heat pump system and its control method, which can solve the problems of poor heat recovery effect and low energy efficiency of existing ground source heat pump systems.

[0008] On one hand, the present invention provides a coaxial sleeve-type underground pipe, the coaxial sleeve-type underground pipe comprising:

[0009] An inner tube and an outer tube are coaxially sleeved together, forming an annular cavity between the inner tube and the outer tube. The top end of the annular cavity is connected to the evaporator outlet of the heat pump unit through an inlet pipe. The top end of the inner tube is connected to the evaporator inlet of the heat pump unit through an outlet pipe, and the bottom end of the inner tube is connected to the annular cavity through a water suction pipe.

[0010] A first solenoid valve is installed at the end of the inlet pipe that connects to the outlet of the evaporator.

[0011] The second solenoid valve is located at the end of the outlet pipe that connects to the evaporator inlet;

[0012] The circulation pipe has its two ends connected to the inlet pipe and the outlet pipe, respectively;

[0013] The third solenoid valve is installed on the circulation pipe;

[0014] The heat exchange medium flows freely and fills the inner tube, the annular cavity, the inlet tube, the outlet tube, and the circulation tube;

[0015] A circulating pump, installed on the circulating pipe, is used to drive the heat exchange medium from the outlet pipe through the circulating pipe to the inlet pipe.

[0016] On the other hand, the present invention provides a ground source heat pump system, the ground source heat pump system comprising:

[0017] Multiple underground pipes are vertically buried underground in the heat source area, and the underground pipes are the aforementioned coaxial sleeve type underground pipes;

[0018] The heat pump unit has its evaporator inlet connected to the outlet pipe of the plurality of buried pipes, and its evaporator outlet connected to the inlet pipe of the plurality of buried pipes.

[0019] Furthermore, the present invention provides a control method based on the above-mentioned ground source heat pump system, the control method comprising:

[0020] S1. Determine the heating period and non-heating period of the ground source heat pump system;

[0021] S2. During the non-heating period, close the first and second solenoid valves of all buried pipes and open the third solenoid valves of all buried pipes. Adjust the ground source heat pump system according to the monitoring data of the heat exchange medium in each buried pipe.

[0022] S3. During the heating season, based on the operating status of the ground source heat pump system at the current time period, all buried pipes are divided into the current heat extraction pipe group and the current heat extraction pipe group; the first and second solenoid valves of all buried pipes in the current heat extraction pipe group are opened and the third solenoid valve is closed, while the first and second solenoid valves of all buried pipes in the current heat extraction pipe group are closed and the third solenoid valve is opened.

[0023] The current heat extraction pipe group and the current heat extraction pipe group to be extracted are adjusted according to the monitoring data of the heat exchange medium in each buried pipe and the heating load of the ground source heat pump system in the next period, so as to regulate the ground source heat pump system.

[0024] Optionally, the monitoring data includes the monitored flow rate of the heat exchange medium in the inlet pipe and the monitored temperature of the heat exchange medium in the outlet pipe.

[0025] Optionally, in S2, the ground source heat pump system is regulated based on monitoring data of the heat exchange medium in each buried pipe, specifically including:

[0026] Turn on the circulation pump in the buried pipe where the monitored flow rate is less than the preset flow rate;

[0027] For buried pipes with a monitored flow rate greater than or equal to the preset flow rate and whose circulation pumps are off, they are sorted from high to low according to their monitored temperature to obtain a first sort. The circulation pumps in the buried pipes located after the preset percentile in the first sort are turned on for a preset time.

[0028] Optionally, in S3, the current heat extraction pipe group and the current heat extraction pipe group to be adjusted based on the monitoring data of the heat exchange medium in each buried pipe and the heating load of the ground source heat pump system in the next time period, specifically including:

[0029] S31. Based on the monitored temperature of each buried pipe in the current heat extraction pipe group, determine the second order of all buried pipes in the current heat extraction pipe group from high to low.

[0030] S32. For the buried pipes in the current heat pipe group whose monitored flow rate is greater than or equal to the preset flow rate and whose circulation pump is closed, sort them from high to low according to their monitored temperature to obtain the third sort.

[0031] S33. Based on the heating load of the ground source heat pump system in the next time period, the second sorting and the third sorting, adjust the current heat extraction pipe group and the current heat extraction pipe group to be extracted.

[0032] Optionally, S32 also includes:

[0033] Turn on the circulation pump in the buried pipe when the monitored flow rate is less than the preset flow rate.

[0034] Optionally, S33 specifically includes:

[0035] S331. Determine the number of buried pipes to be opened in the next time period based on the heating load of the ground source heat pump system in the next time period;

[0036] S332. Adjust the current heat extraction pipe group and the current heat extraction pipe group to be extracted according to the number of underground pipes to be opened in the next time period, the second sorting and the third sorting.

[0037] Optionally, S331 specifically includes:

[0038] The total heat extraction of the ground source heat pump system in the next time period is determined based on the heating load of the ground source heat pump system in the next time period.

[0039] The number of underground pipes to be turned on in the next period is determined based on the total heat extraction volume in the next period.

[0040] Optionally, S332 specifically includes:

[0041] When the number of underground pipes to be opened in the next time period is less than the number of heat pipes in the current heat pipe group, and the absolute difference between the two is M, the last M underground pipes in the second sorting are assigned to the current heat pipe group to be opened.

[0042] When the number of underground pipes to be opened in the next time period is greater than the number of heat pipes in the current heat pipe group, and the absolute difference between the two is N, the first N underground pipes in the third sorting are assigned to the current heat pipe group.

[0043] The beneficial effects that this invention can produce include:

[0044] This invention achieves full-cycle optimized control of the ground source heat pump system. By dynamically allocating and optimizing the heat extraction pipe group and the heat extraction pipe group during the heating season, it effectively avoids the problems of insufficient heat recovery in the buried area due to excessive heat extraction by local buried pipes, or insufficient utilization of ground source heat due to insufficient heat extraction. It balances the heat extraction load of buried pipes in various locations from a global perspective, reduces the uneven heat extraction caused by differences in geological conditions or operating states, and achieves long-term efficient operation of the ground source heat pump system.

[0045] This invention enables proactive heat recovery during the non-heating season. Based on the monitored flow rate and temperature of buried pipes in various locations during the non-heating season, a circulating pump is used to create a stable natural internal circulation flow of the heat exchange medium, thereby increasing the rate of heat recovery from the ground and enabling proactive heat recovery during the non-heating season. This accelerates the heat recovery process and provides thermal storage security for efficient operation in the next heating season.

[0046] This invention innovates a buried pipe structure that supports internal circulation heat recovery. By setting up a circulation pipe to provide an internal circulation path for the heat exchange medium, and by opening and closing a third solenoid valve on the circulation pipe, flexible switching between heat extraction and heat recovery states and flexible control of the internal circulation flow process can be achieved. This allows for the automatic formation of a heat transfer channel between deep and shallow strata during non-heating periods, effectively supplementing the shallow strata with the high-temperature heat from the deep strata, and significantly improving the heat recovery efficiency of the buried area. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the coaxial sleeve-type buried pipe provided in Embodiment 1 of the present invention.

[0048] Figure label:

[0049] 1. Circulation pipe; 2. Third solenoid valve; 3. Circulation pump; 4. Second solenoid valve; 5. First solenoid valve; 6. Temperature sensor; 8. Flow sensor; 9. Outlet pipe; 10. Inlet pipe; 11. Inner pipe; 12. Outer pipe; 13. Suction pipe. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.

[0051] Embodiment 1 of the present invention provides a coaxial sleeve type buried pipe, such as Figure 1 As shown, the coaxial sleeve-type buried pipe includes:

[0052] The outer pipe 12 is vertically buried underground, with its top and bottom ends sealed.

[0053] The inner tube 11 is coaxially inserted into the outer tube 12. An annular cavity is formed between the outer side wall of the inner tube 11 and the inner side wall of the outer tube 12. The top end of the annular cavity is connected to the evaporator outlet of the heat pump unit through the inlet pipe 10. The top end of the inner tube 11 passes through the top end of the outer tube 12 and is connected to the evaporator inlet of the heat pump unit through the outlet pipe 9. The bottom end of the inner tube 11 is connected to the annular cavity through the water suction pipe 13.

[0054] The first solenoid valve 5 is located at the end of the inlet pipe 10 that connects to the evaporator outlet;

[0055] The second solenoid valve 4 is located at the end of the outlet pipe 9 that connects to the evaporator inlet;

[0056] The circulation pipe 1 is connected at both ends to the inlet pipe 10 and the outlet pipe 9, respectively.

[0057] The third solenoid valve 2 is installed on the circulation pipe 1;

[0058] The heat exchange medium is fluid and can flowably fill the inner tube 11, the annular cavity, the inlet tube 10, the outlet tube 9 and the circulation tube 1;

[0059] The circulating pump 3 is installed on the circulating pipe 1 and is used to drive the heat exchange medium from the outlet pipe 9 through the circulating pipe 1 to the inlet pipe 10.

[0060] When heat extraction begins, the first solenoid valve 5 and the second solenoid valve 4 are opened, while the third solenoid valve 2 is closed. The low-temperature heat exchange medium flows out from the evaporator outlet of the heat pump unit and into the annular cavity through the inlet pipe 10. As it flows downward in the annular cavity, it absorbs heat from the soil and rock and heats up. The heated heat exchange medium enters the inner tube 11 from the bottom end through the water suction pipe 13 and flows upward. Finally, it flows into the evaporator inlet of the heat pump unit through the outlet pipe 9 and undergoes heat exchange and cooling through the evaporator of the heat pump unit, forming a closed heat extraction cycle, thereby realizing the extraction of medium-deep geothermal heat.

[0061] When heat extraction stops, the first solenoid valve 5 and the second solenoid valve 4 are closed, preventing the heat exchange medium from circulating between the heat pump unit and the coaxial buried pipe. Simultaneously, the third solenoid valve 2 is opened, connecting the circulation pipe 1, inlet pipe 10, annular cavity, inner pipe 11, and outlet pipe 9 into a closed internal circulation path, allowing the heat exchange medium to circulate within this path. Because the heat exchange medium in the inner pipe 11 has a higher temperature and lower density, while the heat exchange medium in the annular cavity has a lower temperature and higher density, the density difference causes the heat exchange medium in the inner pipe 11 to flow upwards, while the heat exchange medium in the annular cavity flows downwards. The heat exchange medium flowing upward in the inner tube 11 flows back to the annular cavity through the circulation pipe 1. After entering the annular cavity, the heat exchange medium dissipates heat to the surrounding stratum through the outer tube 12, causing its own temperature to drop and its density to increase. As the heat exchange medium flows downward along the annular cavity, the stratum temperature increases with depth. When the temperature of the heat exchange medium is lower than the stratum temperature, the heat exchange medium is heated by the stratum, causing its temperature to rise and its density to decrease. This results in a stable natural internal circulation flow of the heat exchange medium in the inner circulation path, and the heat from the deep stratum is continuously transferred to the shallow stratum through the natural internal circulation flow of the heat exchange medium. This approach maintains a lower temperature in the deep strata surrounding the buried pipe, thereby increasing the temperature difference between the surrounding deep strata and the distant high-temperature strata. This increases the heat transfer efficiency from the distant high-temperature strata to the surrounding deep strata, as well as the heat transfer rate from the surrounding deep strata to the surrounding shallow strata, thus improving heat transfer efficiency, concentrating the heat transfer direction, improving heat recovery, and preventing heat attenuation in the buried area. On the other hand, it allows heat from the deep strata to be transferred and stored in the shallow strata in advance during the non-heating season, increasing the average temperature of the rock strata surrounding the buried pipe. This reduces the cooling rate of the surrounding rock strata during the heating season, effectively improving the heat extraction efficiency and operational stability of the ground source heat pump system.

[0062] Specifically, the specifications and materials of each component in the coaxial sleeve-type buried pipe can be determined according to the design requirements of the ground source heat pump system. For example, the outer pipe 12 is made of J-55 petroleum steel sleeve with an outer diameter of 177.8 mm and a wall thickness of 9.19 mm; the inner pipe 11 can be made of PE-RT II type pipe (outer diameter 110 mm, wall thickness 10 mm) or double-layer insulated steel pipe (outer diameter 114 mm, wall thickness 16.5 mm); the circulation pipe 1 has a diameter of DN65, and the rated flow rate of the circulation pump 3 is 15.0 m³ / s. 3 / h.

[0063] The suction pipe 13 has a water absorption function during both heating and non-heating periods, which can draw the heat exchange medium in the annular cavity into the inner pipe 11. At the same time, the suction pipe 13 can also act as a counterweight for the inner pipe 11 to ensure the installation stability of the inner pipe 11.

[0064] The heat exchange medium can be water or other fluid media that meet the heat exchange requirements.

[0065] Embodiment 2 of the present invention provides a ground source heat pump system, which includes:

[0066] Multiple underground pipes are vertically buried in the underground of the heat source area. These underground pipes are the aforementioned coaxial sleeve type underground pipes.

[0067] The heat pump unit has an evaporator inlet connected to the outlet pipe 9 of multiple buried pipes, and an evaporator outlet connected to the inlet pipe 10 of multiple buried pipes. Its user side is used to supply heat to the target object. The evaporator of the heat pump unit exchanges the ground source heat collected by the multiple buried pipes with its user side, and then transfers it to the target object through its user side.

[0068] Embodiment 3 of the present invention provides a control method based on the above-described ground source heat pump system, the control method comprising:

[0069] S1. Determine the heating and non-heating periods of the ground source heat pump system.

[0070] S2. During the non-heating season, close the first solenoid valve 5 and the second solenoid valve 4 of all buried pipes, and open the third solenoid valve 2 of all buried pipes to form an internal circulation path. Adjust the ground source heat pump system based on the monitoring data of the heat exchange medium within the internal circulation path of each buried pipe, specifically including:

[0071] 1) Obtain monitoring data for the heat exchange medium in each buried pipe. This monitoring data includes the time-period monitoring flow rate of the heat exchange medium in the inlet pipe 10 and the time-period monitoring temperature of the heat exchange medium in the outlet pipe 9.

[0072] In this embodiment, a flow sensor 8 is installed on the inlet pipe 10 to obtain the time-period monitoring flow rate of the heat exchange medium in the inlet pipe 10, and a temperature sensor 6 is installed on the outlet pipe 9 to obtain the time-period monitoring temperature of the heat exchange medium in the outlet pipe 9.

[0073] 2) Turn on the circulation pump 3 in the buried pipe where the monitored flow rate is less than the preset flow rate. The preset flow rate can be flexibly set according to the actual situation. For example, the preset flow rate can be 1.0 m³ / s. 3 / h, 1.5m 3 / h or 2.0 m 3 / h etc.

[0074] If the monitored flow rate is less than the preset flow rate, it indicates that the heat exchange medium has not formed a natural internal circulation flow within the internal circulation path, or the natural internal circulation flow is too slow. In this case, by turning on the circulation pump 3, the flow of the heat exchange medium can be driven or accelerated to form a stable natural internal circulation flow. Once the heat exchange medium has formed a stable natural internal circulation flow, the circulation pump 3 can be turned off. The running time of the circulation pump 3 can be flexibly set according to the actual situation; for example, it can be 2 hours, 3 hours, or 4 hours.

[0075] In practice, after starting the circulation pump 3 and running it for the preset duration, the circulation pump 3 can be turned off, and the monitoring flow rate after turning off the circulation pump 3 can be obtained. If the monitoring flow rate after turning off the circulation pump 3 drops below the preset flow rate again, it indicates that the heat exchange medium has not yet formed a stable natural internal circulation flow. At this time, the circulation pump 3 should be turned on again and run for the preset duration to promote the internal circulation flow. This cycle of starting and stopping the circulation pump 3 continues until the monitoring flow rate after turning off the circulation pump 3 is greater than or equal to the preset flow rate.

[0076] 3) For buried pipes with monitored flow rates greater than or equal to preset flow rates and whose circulating pumps are closed (i.e., buried pipes where the heat exchange medium has formed a stable natural internal circulation flow), sort them from high to low according to their monitored temperatures to obtain the first sort. Then, turn on the circulating pump 3 in the buried pipes located after the preset percentile in the first sort and run it for a preset time.

[0077] The later the monitored temperature of the buried pipe is in the first ranking, the slower the heat transfer rate of the buried pipe and the slower the heat recovery rate of the surrounding strata. At this time, by turning on the circulation pump 3 in the buried pipe that is ranked later, the internal circulation flow rate of its heat exchange medium can be increased, thereby improving the heat transfer rate and promoting heat recovery.

[0078] In practice, for buried pipes where the heat exchange medium has formed a stable natural internal circulation flow, the average monitoring temperature over the previous 72 hours is calculated, and the buried pipes are sorted according to the average monitoring temperature. This eliminates fluctuations in the monitoring temperature and improves the accuracy of the sorting. For buried pipes that have formed a stable natural internal circulation flow for less than 72 hours, the average monitoring temperature since the formation of the stable natural internal circulation flow can be calculated.

[0079] The preset percentile and preset duration can be flexibly set according to the actual situation. For example, the preset percentage can be 3%, 5% or 7%, etc., and the preset duration can be 7 days, 12 days or 15 days, etc.

[0080] During the non-heating season, this embodiment uses the above steps to promote the internal circulation of buried pipes that have not formed a stable natural internal circulation flow by turning on their circulation pump 3; at the same time, buried pipes that have formed a stable natural internal circulation flow are sorted in real time, and buried pipes that are ranked lower are promoted to have their internal circulation flow by turning on their circulation pump 3, thereby ensuring the heat transfer efficiency of all buried pipes and promoting the heat recovery of the buried area during the non-heating season.

[0081] S3. During the heating season, all buried pipes are first divided into the current heat extraction pipe group and the current heat extraction pipe group according to the operating status of the ground source heat pump system at the current time.

[0082] In the current heat extraction pipe group, all buried pipes are in the open state, with the first solenoid valve 5 and the second solenoid valve 4 open and the third solenoid valve 2 closed; in the current heat extraction pipe group, all buried pipes are in the closed state, with the first solenoid valve 5 and the second solenoid valve 4 closed and the third solenoid valve 2 open.

[0083] Then, based on the monitoring data of the heat exchange medium in each buried pipe and the heating load of the ground source heat pump system in the next time period, the current heat extraction pipe group and the current heat extraction pipe group to be extracted are adjusted to regulate the ground source heat pump system, specifically including:

[0084] S31. Based on the monitored temperature of each buried pipe in the current heat extraction pipe group, determine the second order of all buried pipes in the current heat extraction pipe group from high to low.

[0085] In this embodiment, for each buried pipe in the current heat extraction pipe group, it is first determined whether its continuous operating time since its most recent activation (first solenoid valve 5 and second solenoid valve 4 are open and third solenoid valve 2 is closed) has reached 72 hours. For buried pipes that have reached 72 hours, their average monitored temperature in the 72 hours prior to the current moment is calculated; for buried pipes that have not reached 72 hours, their average monitored temperature since the most recent activation is calculated. Then, the buried pipes are sorted from high to low according to their average monitored temperature to obtain a second sort.

[0086] The earlier a buried pipe appears in the second ranking, the higher the temperature of the surrounding strata and the greater its heat extraction potential; conversely, the later a buried pipe appears in the second ranking, the lower the temperature of the surrounding strata and the smaller its heat extraction potential.

[0087] S32. For the buried pipes in the current heat pipe group whose monitored flow rate is greater than or equal to the preset flow rate and whose circulation pump is closed, sort them from high to low according to their monitored temperature to obtain the third sort.

[0088] In this embodiment, for each buried pipe in the current heat pipe group to be harvested, it is determined whether the heat exchange medium inside has formed a stable natural internal circulation flow.

[0089] For buried pipes that have not formed a stable natural internal circulation flow (monitored flow rate is less than the preset flow rate), start its circulation pump 3, and after the circulation pump 3 has run for a preset duration, turn it off. Then, check again whether the heat exchange medium inside has formed a stable natural internal circulation flow. If not, turn the circulation pump 3 off again and run it for the preset duration to promote internal circulation flow. Repeat this cycle of starting and stopping the circulation pump 3 until the heat exchange medium inside the buried pipe forms a stable natural internal circulation flow after the circulation pump 3 is turned off, thereby promoting heat recovery.

[0090] For buried pipes that have established a stable natural internal circulation flow (monitored flow rate is greater than or equal to the preset flow rate, and the circulation pump is off), first determine whether the time since the most recent closure (first solenoid valve 5 and second solenoid valve 4 are closed and third solenoid valve 2 is open) has reached 72 hours. For buried pipes that have reached 72 hours, calculate their average monitored temperature over the 72 hours prior to the current moment; for buried pipes that have not reached 72 hours, calculate their average monitored temperature since the most recent closure. Then, sort the buried pipes from highest to lowest based on their average monitored temperature to obtain a third ranking.

[0091] The earlier a stratum appears in the third ranking, the higher the degree of thermal recovery of the stratum around the buried pipe; the later a stratum appears in the third ranking, the lower the degree of thermal recovery of the stratum around the buried pipe.

[0092] S33. Based on the heating load of the ground source heat pump system in the next time period, the second and third rankings are adjusted to modify the current heat extraction pipe group and the current heat extraction pipe group to be extracted, specifically including:

[0093] S331. Determine the number of buried pipes to be opened in the next time period based on the heating load of the ground source heat pump system in the next time period, specifically including:

[0094] 1) Determine the total heat extraction of the ground source heat pump system in the next time period based on the heating load of the ground source heat pump system in the next time period. The calculation formula is as follows:

[0095] (1)

[0096] In formula (1), for Total heat consumption during the period for Heating load during a given time period It represents the coefficient of performance (COP) of the heat pump unit in a ground source heat pump system.

[0097] The calculation of the total heat extraction is based on existing technology. Since the heat pump unit also consumes some high-grade energy (such as electricity) to supplement the heat supply, the total heat extraction in formula (1) is less than the heat supply load.

[0098] 2) Determine the number of underground pipes to be turned on in the next period based on the total heat collection amount for the next period.

[0099] By calculating the ratio of the total heat extraction in the next period to the designed heat extraction power of a single buried pipe, the number of buried pipes that need to be turned on in the next period can be determined.

[0100] S332. Based on the number of buried pipes to be opened in the next time period, the second sort, and the third sort, adjust the current heat extraction pipe group and the current heat extraction pipe group to be opened, specifically including:

[0101] 1) When the number of underground pipes to be turned on in the next period is less than the number of heat pipes in the current heat pipe group, and the absolute difference between the two is M, the last M underground pipes in the second sort of the current heat pipe group will be turned off and assigned to the current heat pipe group to be turned off. This will ensure that the M underground pipes with the lowest monitored temperature in the current heat pipe group will be turned off first.

[0102] 2) When the number of underground pipes to be opened in the next time period is greater than the number of heat pipes in the current heat pipe group, and the absolute difference between the two is N, the first N underground pipes in the third sort of the current heat pipe group to be opened will be assigned to the current heat pipe group. This will ensure that the N underground pipes with the highest monitored temperature in the current heat pipe group will be opened first.

[0103] 3) After the re-division, the buried pipes in the current heat extraction pipe group and the current heat extraction pipe group are reordered, and the pipe group division is adjusted in time period according to the above process to realize the dynamic control of the ground source heat pump system.

[0104] The above sorting and pipe group division can be performed by the central control unit or PLC to achieve automated operation management.

[0105] This embodiment adopts different operating strategies during the heating season and non-heating season, and dynamically divides the heat extraction pipe group and the heat extraction pipe group during the heating season to achieve differentiated control of different buried pipes. This allows the operating status of the ground source heat pump system to be highly matched with the heating load at each time period, thereby improving the operating energy efficiency of the ground source heat pump system.

[0106] This invention achieves full-cycle optimized control of the ground source heat pump system. By dynamically allocating and optimizing the heat extraction pipe group and the heat extraction pipe group during the heating season, it effectively avoids the problems of insufficient heat recovery in the buried area due to excessive heat extraction by local buried pipes, or insufficient utilization of ground source heat due to insufficient heat extraction. It balances the heat extraction load of buried pipes in various locations from a global perspective, reduces the uneven heat extraction caused by differences in geological conditions or operating states, and achieves long-term efficient operation of the ground source heat pump system.

[0107] This invention enables active heat recovery during the non-heating season. Based on the monitored flow rate and temperature of buried pipes in various locations during the non-heating season, the circulating pump 3 is used to create a stable natural internal circulation flow of the heat exchange medium, thereby increasing the rate of heat recovery from the ground and enabling active heat recovery during the non-heating season. This accelerates the heat recovery process and provides thermal storage assurance for efficient operation in the next heating season.

[0108] This invention innovates a buried pipe structure that supports internal circulation heat recovery. By setting up a circulation pipe 1 to provide an internal circulation path for the heat exchange medium, and by opening and closing the third solenoid valve 2 on the circulation pipe 1, flexible switching between heat extraction and heat recovery states and flexible control of the internal circulation flow process can be achieved. This allows for the automatic formation of a heat transfer channel between deep and shallow strata during non-heating periods, effectively supplementing the high-temperature heat from deep strata to shallow strata and significantly improving the heat recovery efficiency of the buried area.

[0109] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method of regulating a ground source heat pump system, the ground source heat pump system comprising: Multiple coaxial sleeve-type underground pipes are vertically buried underground in the heat source area; The heat pump unit has its evaporator inlet connected to the outlet pipe of the plurality of coaxial sleeve-type buried pipes, and its evaporator outlet connected to the inlet pipe of the plurality of coaxial sleeve-type buried pipes. The coaxial sleeve-type buried pipe includes: an inner pipe and an outer pipe coaxially sleeved together, forming an annular cavity between the inner pipe and the outer pipe; the top end of the annular cavity is connected to the evaporator outlet through an inlet pipe; the top end of the inner pipe is connected to the evaporator inlet through an outlet pipe; and the bottom end of the inner pipe is connected to the annular cavity through a suction pipe; a first solenoid valve is disposed at one end of the inlet pipe connected to the evaporator outlet; a second solenoid valve is disposed at one end of the outlet pipe connected to the evaporator inlet; a circulation pipe, the two ends of which are respectively connected to the inlet pipe and the outlet pipe; a third solenoid valve is disposed on the circulation pipe; a heat exchange medium that can flowably fill the inner pipe, the annular cavity, the inlet pipe, the outlet pipe, and the circulation pipe; and a circulation pump disposed on the circulation pipe for driving the heat exchange medium to flow from the outlet pipe through the circulation pipe to the inlet pipe; characterized in that the control method includes: S1. Determine the heating period and non-heating period of the ground source heat pump system; S2. During the non-heating period, close the first and second solenoid valves of all buried pipes and open the third solenoid valves of all buried pipes to obtain the monitoring flow rate of the heat exchange medium in the inlet pipe and the monitoring temperature of the heat exchange medium in the outlet pipe; turn on the circulation pump in the buried pipe with a monitoring flow rate less than the preset flow rate; for the buried pipes with a monitoring flow rate greater than or equal to the preset flow rate and the circulation pump is closed, sort them from high to low according to their monitoring temperature to obtain a first sort, and turn on the circulation pump in the buried pipes located after the preset percentile in the first sort for a preset time. S3. During the heating season, based on the operating status of the ground source heat pump system at the current time period, all buried pipes are divided into the current heat extraction pipe group and the current heat extraction pipe group; the first and second solenoid valves of all buried pipes in the current heat extraction pipe group are opened and the third solenoid valve is closed, while the first and second solenoid valves of all buried pipes in the current heat extraction pipe group are closed and the third solenoid valve is opened. The current heat extraction pipe group and the current heat extraction pipe group to be extracted are adjusted according to the monitoring data of the heat exchange medium in each buried pipe and the heating load of the ground source heat pump system in the next period, so as to regulate the ground source heat pump system. S3 adjusts the current heat extraction pipe group and the current heat extraction pipe group based on the monitoring data of the heat exchange medium in each buried pipe and the heating load of the ground source heat pump system in the next time period, specifically including: S31. Based on the monitored temperature of each buried pipe in the current heat extraction pipe group, determine the second order of all buried pipes in the current heat extraction pipe group from high to low. S32. For the buried pipes in the current heat pipe group whose monitored flow rate is greater than or equal to the preset flow rate and whose circulation pump is closed, sort them from high to low according to their monitored temperature to obtain the third sort. S33. Based on the heating load of the ground source heat pump system in the next time period, the second sorting and the third sorting, adjust the current heat extraction pipe group and the current heat extraction pipe group to be extracted.

2. The method of claim 1, wherein, S32 also includes: Turn on the circulation pump in the buried pipe when the monitored flow rate is less than the preset flow rate.

3. The method of claim 1, wherein, S33 specifically includes: S331. Determine the number of buried pipes to be opened in the next time period based on the heating load of the ground source heat pump system in the next time period; S332. Adjust the current heat extraction pipe group and the current heat extraction pipe group to be extracted according to the number of underground pipes to be opened in the next time period, the second sorting and the third sorting.

4. The method of claim 3, wherein, S331 specifically includes: The total heat extraction of the ground source heat pump system in the next time period is determined based on the heating load of the ground source heat pump system in the next time period. The number of underground pipes to be turned on in the next period is determined based on the total heat extraction volume in the next period.

5. The method of claim 3, wherein, S332 specifically includes: When the number of underground pipes to be opened in the next time period is less than the number of heat pipes in the current heat pipe group, and the absolute difference between the two is M, the last M underground pipes in the second sorting are assigned to the current heat pipe group to be opened. When the number of underground pipes to be opened in the next time period is greater than the number of heat pipes in the current heat pipe group, and the absolute difference between the two is N, the first N underground pipes in the third sorting are assigned to the current heat pipe group.

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