Solar heat collection loop anti-freezing system and method

Abstract

The invention discloses a solar heat collection loop anti-freezing system and method. A solar heat collection loop anti-freezing system comprises a heat storage water tank, a heat collection unit and a geothermal device, the heat collection unit is connected with the heat storage water tank, and the heat collection unit collects heat energy of sunlight and conveys and stores the heat energy into the heat storage water tank. The heat collection unit is provided with a heat collector, a working medium inlet pipeline connected to the inlet end of the heat collector and a working medium outlet pipeline connected to the outlet end of the heat collector, and the heat collector, at least part of the working medium inlet pipeline and at least part of the working medium outlet pipeline are all located outdoors. The terrestrial heat device is connected with the working medium inlet pipeline and the working medium outlet pipeline, and a working medium in the terrestrial heat device circularly flows or indirectly exchanges heat with a working medium in the heat collection unit so as to heat at least part of the working medium in the heat collection unit through terrestrial heat energy. Anti-freezing of a heat collection loop is achieved, the stability of a heat collection pipe network in an alpine region is improved, the heat collection pipe network is prevented from being broken or frozen, and the reliability of the whole system is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of solar heat collection, and in particular relates to a solar heat collection loop antifreeze system and method. Background Art

[0002] In high-altitude mountainous areas, since it is difficult to extend the power grid and hot water pipelines to some remote areas, collectors are usually used for heating. Due to the low temperature and large temperature difference between day and night in high-altitude mountainous areas, the pipelines of the collector system are easily frozen and difficult to thaw, resulting in the inability to operate the collector system and even causing pipeline ruptures, which greatly affects the stability of the equipment.

[0003] In the related art, an insulation sleeve is wrapped on the outside of the pipeline, but the anti-freezing problem cannot be effectively solved. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention provides a solar energy heat collection loop antifreeze system capable of achieving heat collection loop antifreeze.

[0006] The embodiment of the present invention also provides a method for preventing freezing of a solar heat collection loop.

[0007] The solar heat collection loop antifreeze system of the embodiment of the present invention comprises:

[0008] Hot water storage tank;

[0009] A heat collecting unit, the heat collecting unit is connected to the heat storage tank, the heat collecting unit collects heat energy from sunlight and transports and stores the heat energy in the heat storage tank, the heat collecting unit comprises a heat collector, a working fluid inlet pipeline connected to the inlet end of the heat collector, and a working fluid outlet pipeline connected to the outlet end of the heat collector, the heat collector, at least part of the working fluid inlet pipeline, and at least part of the working fluid outlet pipeline are all located outdoors;

[0010] A geothermal device is connected to the working fluid inlet pipeline and the working fluid outlet pipeline, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the heat collection unit to utilize geothermal energy to heat at least part of the working fluid in the heat collection unit.

[0011] The embodiments of the present invention can realize self-circulation of the working fluid of the heat collection unit and circulating flow or indirect heat exchange between the working fluid in the heat collection unit and the working fluid in the geothermal device, thereby realizing antifreeze of the heat collection loop, improving the stability of the heat collection pipe network in high-altitude and cold areas, avoiding rupture or freezing of the heat collection pipe network, and improving the reliability of the entire system.

[0012] In some embodiments, the working fluid in the geothermal device and the thermal collection unit is the same, and the geothermal device includes a first pump and a first pipeline, both ends of the first pipeline are respectively connected to the working fluid inlet pipeline and the working fluid outlet pipeline, and a partial section of the first pipeline is located in the underground formation, and the first pump is used to drive the working fluid in the outdoor part of the thermal collection unit and the working fluid in the first pipeline to circulate.

[0013] In some embodiments, a first interface and a second interface are respectively provided at both ends of the working fluid inlet pipeline located outdoors, and the first interface and the second interface are respectively connected to the two ends of the first pipeline; a third interface and a fourth interface are respectively provided at both ends of the working fluid outlet pipeline located outdoors, and the third interface and the fourth interface are respectively connected to the two ends of the first pipeline.

[0014] In some embodiments, the working fluid in the geothermal device is different from the working fluid in the thermal collection unit. The geothermal device includes a first heat exchanger, a second pump, a third pump, a liquid intake pipeline and a liquid return pipeline. The liquid intake pipeline and the liquid return pipeline are connected to the hot side pipeline of the first heat exchanger, and the cold side pipeline of the first heat exchanger is connected to the working fluid inlet pipeline and the working fluid outlet pipeline. The liquid intake pipeline extends into the underground formation for extracting groundwater, and the liquid return pipeline is used to reinject the groundwater after heat exchange into the underground or transport it to a storage area. The second pump is arranged on the liquid intake pipeline, and the third pump is connected to the cold side pipeline to drive the working fluid in the outdoor part of the thermal collection unit to circulate after heat exchange through the cold side pipeline.

[0015] In some embodiments, a first interface and a second interface are respectively provided at both ends of the working fluid inlet pipeline located outdoors, and the first interface and the second interface are respectively connected to the two ends of the cold side pipeline; a third interface and a fourth interface are respectively provided at both ends of the working fluid outlet pipeline located outdoors, and the third interface and the fourth interface are respectively connected to the two ends of the cold side pipeline.

[0016] In some embodiments, the geothermal device, the working fluid inlet pipeline and the working fluid outlet pipeline are all provided with control valves, and the multiple control valves operate independently to adjust the working fluid inlet pipeline to form a circulation pipeline with the geothermal device, or the working fluid outlet pipeline to form a circulation pipeline with the geothermal device, or the outdoor part of the thermal collection unit to form a circulation pipeline with the geothermal device.

[0017] In some embodiments, it also includes multiple temperature detection components and multiple flow detection components, the multiple temperature detection components are respectively arranged on the collector, the working fluid inlet pipeline and the working fluid outlet pipeline, and the multiple flow detection components are arranged on the working fluid inlet pipeline and the working fluid outlet pipeline.

[0018] In some embodiments, a second heat exchanger is provided between the hot water storage tank and the heat collection unit, and the working fluid of the heat collection unit and the working fluid in the hot water storage tank exchange heat in the second heat exchanger;

[0019] And / or, it also includes the insulation sleeve, which is installed on the pipeline in the heat collection unit, the pipeline above the ground in the geothermal device, and the pipeline below the ground in the geothermal device and with a distance from the ground less than or equal to a first preset value.

[0020] In some embodiments, a pit and a lifting platform are further included, wherein the lifting platform is disposed at the bottom of the pit, the heat collector is connected to the lifting platform, and the lifting platform is used to drive the heat collector to rise and fall so that the heat collector falls into the pit or extends out of the ground;

[0021] A cover plate is provided on the top of the pit.

[0022] The solar energy heat collection loop antifreeze method of the embodiment of the present invention adopts the solar energy heat collection loop antifreeze system described in any of the above embodiments to perform antifreeze, and specifically comprises the following steps:

[0023] Obtaining the working fluid temperature Q1 in the collector and the working fluid temperature Q2 in the outdoor pipeline of the collector unit;

[0024] Determine whether the working fluid temperature Q1 is greater than or equal to a first threshold, and whether the working fluid temperature Q2 is less than or equal to a second threshold, and the first threshold is greater than the second threshold;

[0025] If yes, the heat collection unit starts in a self-circulating manner and stops after running for a time T1;

[0026] Determine whether the working fluid temperature Q1 is greater than or equal to a third threshold and less than the first threshold, whether the working fluid temperature Q2 is less than or equal to a second threshold, and the third threshold is less than the first threshold and greater than the second threshold;

[0027] If yes, the heat collection unit starts self-circulation and continues to operate until the working medium temperature Q1 is lower than the third threshold;

[0028] Determine whether the working fluid temperature Q1 is greater than a second threshold and less than a third threshold, and whether the working fluid temperature Q2 is less than or equal to the second threshold;

[0029] If yes, the geothermal device is started, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the outdoor pipeline of the heat collection unit;

[0030] Determine whether the working fluid temperature Q1 is less than or equal to a second threshold, and whether the working fluid temperature Q2 is less than or equal to a second threshold;

[0031] If so, the geothermal device is started, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the collector and the working fluid in the outdoor part pipeline in the heat collection unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of a solar thermal collection loop antifreeze system according to an embodiment of the present invention.

[0033] Figure 2 It is a schematic diagram of a solar thermal collection loop antifreeze system according to another embodiment of the present invention.

[0034] Figure 3 It is a schematic diagram of a solar energy collection loop antifreeze system according to another embodiment of the present invention.

[0035] Figure 4 It is a schematic diagram of the arrangement structure of the collector in the embodiment of the present invention.

[0036] Reference numerals:

[0037] 100. Solar collector loop antifreeze system;

[0038] 1. Heat collecting unit; 11. Heat collector; 12. Working fluid inlet pipeline; 13. Working fluid outlet pipeline; 14. First interface; 15. Second interface; 16. Third interface; 17. Fourth interface;

[0039] 2. Hot water storage tank;

[0040] 3. Geothermal device; 31. First pump; 32. First pipeline; 33. First heat exchanger; 34. Second pump; 35. Third pump; 36. Liquid extraction pipeline; 37. Liquid return pipeline;

[0041] 4. Second heat exchanger;

[0042] 5. Pit; 51. Lifting platform;

[0043] 6. Insulation cover. DETAILED DESCRIPTION

[0044] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0045] like Figures 1 to 3 As shown, the solar thermal collection loop antifreeze system 100 according to an embodiment of the present invention includes a hot water storage tank 2 , a thermal collection unit 1 and a geothermal device 3 .

[0046] The heat collecting unit 1 is connected to the hot water storage tank 2. The heat collecting unit 1 collects the heat energy of sunlight and transports and stores the heat energy in the hot water storage tank 2. The heat collecting unit 1 has a collector 11, a working fluid inlet pipeline 12 connected to the inlet end of the collector 11, and a working fluid outlet pipeline 13 connected to the outlet end of the collector 11. The collector 11, at least part of the working fluid inlet pipeline 12, and at least part of the working fluid outlet pipeline 13 are all located outdoors.

[0047] The geothermal device 3 is connected to the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13. The working fluid in the geothermal device 3 circulates or indirectly exchanges heat with the working fluid in the heat collection unit 1 to heat at least part of the working fluid in the heat collection unit 1 using geothermal energy.

[0048] The geothermal device 3 uses the geothermal energy under the stratum to heat the working fluid in the collector 11, the working fluid inlet pipeline 12, and the working fluid outlet pipeline 13, so as to maintain the working fluid in the heat collection unit 1 above the freezing point under the low temperature state at night. The embodiment of the present invention can realize the self-circulation of the working fluid of the heat collection unit 1 and the circulation flow or indirect heat exchange of the working fluid in the heat collection unit 1 and the working fluid in the geothermal device 3, realize the antifreeze of the heat collection loop, improve the stability of the heat collection pipe network in high-cold areas, avoid the rupture or freezing of the heat collection pipe network, and improve the reliability of the entire system.

[0049] When the working fluid in the heat collecting unit 1 is water, the geothermal device 3 can directly form a circulation with the working fluid in the heat collecting unit 1 by extracting groundwater, or it can perform indirect heat exchange through a heat exchanger; when the working fluid in the heat collecting unit 1 is antifreeze, the geothermal device 3 can directly form a circulation with the working fluid in the heat collecting unit 1 by extracting groundwater, or it can make the pipeline of the geothermal device 3 and the pipeline in the heat collecting unit 1 form a circulation pipeline to transport the working fluid to the underground and then return to the heat collecting unit 1.

[0050] like Figure 2 As shown, in some embodiments, the working fluid in the geothermal device 3 and the heat collecting unit 1 is the same, the geothermal device 3 includes a first pump 31 and a first pipeline 32, both ends of the first pipeline 32 are respectively connected to the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13, a partial section of the first pipeline 32 is located in the underground formation, and the first pump 31 is used to drive the working fluid in the outdoor part of the heat collecting unit 1 and the working fluid in the first pipeline 32 to circulate.

[0051] Specifically, in order to prevent the freezing point from being too high due to the use of water as the working fluid in the heat collecting unit 1, the working fluids in the geothermal device 3 and the heat collecting unit 1 of the embodiment of the present invention both use antifreeze. At this time, the working fluid in the first pipeline 32 and the working fluid in the heat collecting unit 1 form a circulation, and the first pump 31 pumps the low-temperature working fluid in the heat collecting unit 1 into the underground formation. The low-temperature working fluid absorbs heat and heats up in the underground formation, and then flows back to the heat collecting unit 1.

[0052] Optionally, when the pipeline of the geothermal device 3 and the pipeline in the heat collecting unit 1 form a circulation pipeline, the first pipeline 32 of the geothermal device 3 can be drilled and laid by directional drilling.

[0053] Furthermore, a first interface 14 and a second interface 15 are respectively provided at both ends of the working fluid inlet pipeline 12 located outdoors, and the first interface 14 and the second interface 15 are respectively connected to the two ends of the first pipeline 32; a third interface 16 and a fourth interface 17 are respectively provided at both ends of the working fluid outlet pipeline 13 located outdoors, and the third interface 16 and the fourth interface 17 are respectively connected to the two ends of the first pipeline 32.

[0054] In the embodiment of the present invention, the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13 located outdoors are arranged in parallel and are both connected to the first pipeline 32. At this time, according to actual conditions, only the working fluid in the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13 can be subjected to antifreeze circulation operation. When the working fluid temperature in the collector 11 is also too low, the working fluid in the outdoor part of the collector unit 1 can be subjected to antifreeze circulation operation.

[0055] Therefore, the embodiment of the present invention can more effectively utilize the residual heat of the working fluid inside the thermal collection unit 1 to realize its own antifreeze circulation operation. When night just comes, the residual heat of the working fluid inside the thermal collection unit 1 can be used to realize self-circulation. When the working fluid temperature in the pipeline of the thermal collection unit 1 is lower than the working fluid temperature inside the collector 11, and the working fluid temperature inside the collector 11 can still ensure that it will not freeze, then the geothermal device 3 can be used to only perform antifreeze circulation operation on the working fluid in the pipeline, thereby reducing energy consumption and improving energy utilization. When the working fluid temperature of the outdoor part of the thermal collection unit 1 is low and there is a risk of freezing, the geothermal device 3 can be used to prevent freezing of the working fluid in the outdoor part of the thermal collection unit 1.

[0056] like Figure 3 As shown, in some embodiments, the working fluid in the geothermal device 3 is different from the working fluid in the heat collection unit 1. The geothermal device 3 includes a first heat exchanger 33, a second pump 34, a third pump 35, a liquid intake pipeline 36 and a liquid return pipeline 37. The liquid intake pipeline 36 and the liquid return pipeline 37 are connected to the hot side pipeline of the first heat exchanger 33. The cold side pipeline of the first heat exchanger 33 is connected to the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13. The liquid intake pipeline 36 extends into the underground stratum for extracting groundwater. The liquid return pipeline 37 is used to recharge the groundwater after heat exchange into the underground or transport it to the storage area. The second pump 34 is arranged on the liquid intake pipeline 36. The second pump 34 is used to extract groundwater into the hot side pipeline of the first heat exchanger 33. The third pump 35 is connected to the cold side pipeline to drive the working fluid in the outdoor part of the heat collection unit 1 to circulate after heat exchange through the cold side pipeline.

[0057] In the embodiment of the present invention, the working fluid in the heat collecting unit 1 is antifreeze, and the working fluid in the geothermal device 3 is groundwater. At this time, the antifreeze in the heat collecting unit 1 and the groundwater in the geothermal device 3 indirectly exchange heat through the first heat exchanger 33. The geothermal device 3 extracts groundwater from the underground stratum through the liquid extraction pipeline 36. After heat exchange and cooling in the first heat exchanger 33, the groundwater can be re-injected into the ground, or stored as domestic water, saving energy.

[0058] At this time, the boreholes of the liquid intake pipeline 36 and the liquid return pipeline 37 can be drilled vertically until they reach the groundwater layer.

[0059] Furthermore, a first interface 14 and a second interface 15 are respectively provided at both ends of the working fluid inlet pipeline 12 located outdoors, and the first interface 14 and the second interface 15 are respectively connected to the two ends of the cold side pipeline; a third interface 16 and a fourth interface 17 are respectively provided at both ends of the working fluid outlet pipeline 13 located outdoors, and the third interface 16 and the fourth interface 17 are respectively connected to the two ends of the cold side pipeline.

[0060] In the embodiment of the present invention, the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13 located outdoors are arranged in parallel and are both connected to the cold side pipeline of the first heat exchanger 33. At this time, according to actual conditions, only the working fluid in the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13 can be subjected to antifreeze circulation operation. When the working fluid temperature in the collector 11 is also too low, the working fluid in the outdoor part of the collector unit 1 can be subjected to antifreeze circulation operation.

[0061] In some embodiments, control valves are provided on the geothermal device 3, the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13, and multiple control valves operate independently to adjust the working fluid inlet pipeline 12 and the geothermal device 3 to form a circulation pipeline, or the working fluid outlet pipeline 13 and the geothermal device 3 to form a circulation pipeline, or the outdoor part of the thermal collection unit 1 and the geothermal device 3 to form a circulation pipeline.

[0062] The control valve is a solenoid valve. By controlling the opening and closing of different solenoid valves, different pipelines can be connected and disconnected, thereby forming different circulation pipelines. After monitoring the working fluid temperature in different sections of the outdoor part of the thermal collector unit 1, the working fluid that needs to be antifreeze cycle can be determined more effectively and reasonably, and then the antifreeze system can be started, thereby improving the utilization rate of the residual heat in the thermal collector unit 1 and reducing the loss of original heat in the thermal collector unit 1.

[0063] Furthermore, the solar thermal collection loop antifreeze system 100 also includes multiple temperature detection components and multiple flow detection components. The multiple temperature detection components are respectively arranged on the collector 11, the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13, and the multiple flow detection components are arranged on the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13.

[0064] Temperature detection components and flow detection components are provided at the inlet and hot air outlet of the collector 11, the working fluid inlet pipeline 12 and the working fluid outlet pipeline 13 outdoors, for obtaining temperature data at different locations in real time, facilitating the formulation of antifreeze strategies.

[0065] like Figure 3 As shown, in some embodiments, a second heat exchanger 4 is provided between the hot water storage tank 2 and the thermal collection unit 1 , and the working fluid in the thermal collection unit 1 and the working fluid in the hot water storage tank 2 exchange heat in the second heat exchanger 4 .

[0066] In order to prevent freezing, the working medium inside the thermal collecting unit 1 is antifreeze, and the working medium in the hot water storage tank 2 is water. Therefore, during the heat storage process, a second heat exchanger 4 is arranged between the thermal collecting unit 1 and the hot water storage tank 2, so that the heat in the working medium in the thermal collecting unit 1 is transferred to the working medium in the hot water storage tank 2 by indirect heat exchange.

[0067] The first heat exchanger 33 and the second heat exchanger 4 in the embodiment of the present invention are both plate heat exchangers.

[0068] like Figure 4 As shown, in some embodiments, the solar thermal collection loop antifreeze system 100 also includes an insulation sleeve 6, which is arranged on the pipeline in the thermal collection unit 1, the pipeline above the ground in the geothermal device 3, and the pipeline below the ground in the geothermal device 3 and the distance from the ground is less than or equal to a first preset value.

[0069] The insulation sleeve 6 is supported by polyethylene insulation material, and the thickness of the insulation sleeve 6 can be 10 mm to 20 mm.

[0070] The first preset value can be 1000mm to 4500mm, as shown in the distance A in the figure. Since the underground stratum temperature less than the first preset value is still relatively low, in order to avoid freezing and cracking of the pipeline, the embodiment of the present invention is provided with an insulation sleeve 6 on all pipelines above the ground outdoors, and an insulation sleeve 6 is also provided on the pipeline below the ground at a distance less than the first preset value from the ground to improve the insulation effect.

[0071] The stratum has a natural heat-insulating effect. Therefore, there is no need to set a heat-insulating sleeve 6 on the underground pipeline whose distance from the ground is greater than the first preset value, which is convenient for construction.

[0072] like Figure 4 As shown, in some embodiments, it also includes a pit 5 and a lifting platform 51, the lifting platform 51 is arranged at the bottom of the pit 5, the collector 11 is connected to the lifting platform 51, and the lifting platform 51 is used to drive the collector 11 to rise and fall so that the collector 11 falls into the pit 5 or extends out of the ground; a cover plate is provided on the top of the pit 5.

[0073] When the collector 11 is in an open-air state, the temperature of the working fluid inside the collector 11 dissipates too quickly. In the embodiment of the present invention, a pit 5 is set up, a lifting platform 51 is placed in the pit 5, and the collector 11 is placed on the lifting platform 51. During the day, the lifting platform 51 lifts the collector 11 so that sunlight can illuminate the collector 11 to achieve solar energy collection. At night, the lifting platform 51 falls back and the collector 11 falls back into the pit 5. A cover plate is set on the top of the pit 5 to form a relatively closed space in the pit 5, which can greatly reduce the heat loss of the collector 11. The stratum has thermal insulation properties. Therefore, the remaining heat of the working fluid in the collector 11 can be maintained for a longer time to prevent the working fluid from freezing.

[0074] The lifting platform 51 may be a scissor lift.

[0075] The solar energy heat collection loop antifreeze method of the embodiment of the present invention adopts the solar energy heat collection loop antifreeze system of any of the above embodiments to perform antifreeze, and specifically comprises the following steps:

[0076] S101, obtaining the working fluid temperature Q1 in the collector and the working fluid temperature Q2 in the outdoor pipe of the collector unit. The collector has a better heat preservation effect than the outdoor pipe, so the working fluid temperature in the collector drops slowly, while the working fluid temperature in the outdoor pipe of the collector unit drops quickly. The embodiment of the present invention can further improve the utilization rate of the residual heat in the collector unit according to the difference between the two temperatures.

[0077] S102, determining whether the working fluid temperature Q1 is greater than or equal to a first threshold, and whether the working fluid temperature Q2 is less than or equal to a second threshold, and the first threshold is greater than the second threshold.

[0078] S103: If yes, the heat collection unit starts the self-circulation and stops after running for T1 time.

[0079] That is to say, the second threshold value can be 2-5 degrees Celsius higher than the freezing point temperature of the working fluid in the thermal collection unit. When the working fluid temperature Q2 in the outdoor pipeline of the thermal collection unit is lower than the second threshold value, there is a risk of freezing. At this time, by starting the self-circulation of the thermal collection unit, the working fluid inside the collector and the working fluid in the outdoor pipeline of the thermal collection unit circulate for time T1, which is an intermittent circulation mode.

[0080] By repeating S102 and S103, the heat collection unit can be protected from freezing within a certain period of time.

[0081] S104, determining whether the working fluid temperature Q1 is greater than or equal to a third threshold and less than the first threshold, whether the working fluid temperature Q2 is less than or equal to a second threshold, and the third threshold is less than the first threshold and greater than the second threshold.

[0082] S105: If yes, the heat collection unit starts the self-circulation and continues to operate until the working medium temperature Q1 is lower than the third threshold.

[0083] That is to say, when the antifreeze operation using steps S102 and S103 requires frequent starts and stops, and the start and stop frequency is too high, the intermittent cycle mode is converted into a continuous operation mode.

[0084] Repeat steps S104 and S105 until the working medium temperature Q1 in the collector is low and can no longer provide heat or the remaining heat of the working medium in the collector can only ensure that the collector itself does not freeze within a certain period of time, then stop using this antifreeze method.

[0085] In the above embodiment, the first threshold value may be 30 degrees Celsius, the second threshold value may be 2 to 5 degrees Celsius higher than the freezing point temperature of the working fluid, and the third threshold value may be 15 degrees Celsius.

[0086] When the working medium temperature Q1 in the collector is lower than the third threshold value, the working medium in the collector is no longer used to protect the collector unit from freezing.

[0087] S106 , determining whether the working fluid temperature Q1 is greater than the second threshold and less than the third threshold, and whether the working fluid temperature Q2 is less than or equal to the second threshold.

[0088] S107: If yes, the geothermal device is started, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the outdoor pipeline of the heat collection unit.

[0089] That is to say, the working fluid in the collector will not freeze at this time, but when the working fluid in the outdoor pipeline of the collector unit faces the risk of freezing, the geothermal device is started to prevent the working fluid in the outdoor pipeline of the collector unit from freezing, and the geothermal energy is used to heat the working fluid in the outdoor pipeline of the collector unit.

[0090] S108, determining whether the working fluid temperature Q1 is less than or equal to a second threshold, and whether the working fluid temperature Q2 is less than or equal to a second threshold.

[0091] S109: If yes, the geothermal device is started, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the collector and the working fluid in the outdoor part of the pipeline in the heat collection unit.

[0092] When the working fluid in the collector and the working fluid in the outdoor pipelines of the collector unit are facing the risk of freezing, the geothermal device is started to prevent all the working fluids outside the collector unit from freezing, and geothermal energy is used to heat all the working fluids outside the collector unit.

[0093] The geothermal device of the embodiment of the present invention utilizes relatively stable geothermal energy to achieve antifreeze of the heat collection system, and has higher reliability. By rationally allocating antifreeze strategies according to different stages, energy consumption can be reduced and utilization efficiency can be improved.

[0094] Furthermore, the embodiments of the present invention can also realize the coupled utilization of geothermal energy and solar energy, providing a more effective solution for heating work in high-altitude and cold regions.

[0095] Furthermore, when the temperature of the water in the hot water storage tank drops and is insufficient to be supplied to the heating equipment, the heat in the hot water storage tank can be used to heat the working fluid in the thermal collecting unit at night, thereby improving the utilization rate of the heat in the hot water storage tank. When the heat in the hot water storage tank is used to heat the working fluid in the thermal collecting unit, the operation of the geothermal device is stopped until the heat in the hot water storage tank cannot meet the antifreeze requirements of the working fluid in the thermal collecting unit, and then the geothermal device is started.

[0096] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0097] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0098] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0099] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0100] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0101] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A solar heat collection loop antifreeze system, characterized in that: include: Hot water storage tank; A heat collecting unit, the heat collecting unit is connected to the heat storage tank, the heat collecting unit collects heat energy from sunlight and transports and stores the heat energy in the heat storage tank, the heat collecting unit comprises a heat collector, a working fluid inlet pipeline connected to the inlet end of the heat collector, and a working fluid outlet pipeline connected to the outlet end of the heat collector, the heat collector, at least part of the working fluid inlet pipeline, and at least part of the working fluid outlet pipeline are all located outdoors; A geothermal device is connected to the working fluid inlet pipeline and the working fluid outlet pipeline, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the heat collection unit to utilize geothermal energy to heat at least part of the working fluid in the heat collection unit.

2. The solar heat collection loop antifreeze system according to claim 1, characterized in that: The working fluid in the geothermal device is the same as that in the heat collection unit. The geothermal device includes a first pump and a first pipeline. The two ends of the first pipeline are respectively connected to the working fluid inlet pipeline and the working fluid outlet pipeline. A partial section of the first pipeline is located in the underground formation. The first pump is used to drive the working fluid in the outdoor part of the heat collection unit and the working fluid in the first pipeline to circulate.

3. The solar heat collection loop antifreeze system according to claim 2, characterized in that: The two ends of the working fluid inlet pipeline located outdoors are respectively provided with a first interface and a second interface, and the first interface and the second interface are respectively connected to the two ends of the first pipeline; the two ends of the working fluid outlet pipeline located outdoors are respectively provided with a third interface and a fourth interface, and the third interface and the fourth interface are respectively connected to the two ends of the first pipeline.

4. The solar heat collection loop antifreeze system according to claim 1, characterized in that: The working fluid in the geothermal device is different from the working fluid in the heat collection unit. The geothermal device includes a first heat exchanger, a second pump, a third pump, a liquid intake pipeline and a liquid return pipeline. The liquid intake pipeline and the liquid return pipeline are connected to the hot side pipeline of the first heat exchanger, and the cold side pipeline of the first heat exchanger is connected to the working fluid inlet pipeline and the working fluid outlet pipeline. The liquid intake pipeline extends into the underground stratum for extracting groundwater, and the liquid return pipeline is used to reinject the groundwater after heat exchange into the underground or transport it to a storage area. The second pump is arranged on the liquid intake pipeline, and the third pump is connected to the cold side pipeline to drive the working fluid in the outdoor part of the heat collection unit to circulate after heat exchange through the cold side pipeline.

5. The solar heat collection loop antifreeze system according to claim 4, characterized in that: The two ends of the working fluid inlet pipeline located outdoors are respectively provided with a first interface and a second interface, and the first interface and the second interface are respectively connected to the two ends of the cold side pipeline; the two ends of the working fluid outlet pipeline located outdoors are respectively provided with a third interface and a fourth interface, and the third interface and the fourth interface are respectively connected to the two ends of the cold side pipeline.

6. The solar heat collection loop antifreeze system according to claim 1, characterized in that: The geothermal device, the working fluid inlet pipeline and the working fluid outlet pipeline are all provided with control valves, and the multiple control valves act independently to adjust the working fluid inlet pipeline and the geothermal device to form a circulation pipeline, or the working fluid outlet pipeline and the geothermal device to form a circulation pipeline, or the outdoor part of the heat collection unit and the geothermal device to form a circulation pipeline.

7. The solar heat collection loop antifreeze system according to claim 1, characterized in that: It also includes multiple temperature detection components and multiple flow detection components. The multiple temperature detection components are respectively arranged on the collector, the working fluid inlet pipeline and the working fluid outlet pipeline, and the multiple flow detection components are arranged on the working fluid inlet pipeline and the working fluid outlet pipeline.

8. The solar heat collection loop antifreeze system according to claim 1, characterized in that: A second heat exchanger is provided between the hot water storage tank and the heat collecting unit, and the working fluid of the heat collecting unit and the working fluid in the hot water storage tank exchange heat in the second heat exchanger; And / or, it also includes the insulation sleeve, which is installed on the pipeline in the heat collection unit, the pipeline above the ground in the geothermal device, and the pipeline below the ground in the geothermal device and with a distance from the ground less than or equal to a first preset value.

9. The solar heat collection loop antifreeze system according to claim 1, characterized in that: It also includes a pit and a lifting platform, wherein the lifting platform is arranged at the bottom of the pit, the collector is connected to the lifting platform, and the lifting platform is used to drive the collector to rise and fall so that the collector falls into the pit or extends out of the ground; A cover plate is provided on the top of the pit.

10. A method for preventing freezing of a solar heat collection loop, characterized in that: The antifreeze system for the solar thermal collector loop according to any one of claims 1 to 9 is used for antifreeze, and specifically comprises the following steps: Obtaining the working fluid temperature Q1 in the collector and the working fluid temperature Q2 in the outdoor pipeline of the collector unit; Determine whether the working fluid temperature Q1 is greater than or equal to a first threshold, and whether the working fluid temperature Q2 is less than or equal to a second threshold, and the first threshold is greater than the second threshold; If yes, the heat collection unit starts in a self-circulating manner and stops after running for a time T1; Determine whether the working fluid temperature Q1 is greater than or equal to a third threshold and less than the first threshold, whether the working fluid temperature Q2 is less than or equal to a second threshold, and the third threshold is less than the first threshold and greater than the second threshold; If yes, the heat collection unit starts self-circulation and continues to operate until the working medium temperature Q1 is lower than the third threshold; Determine whether the working fluid temperature Q1 is greater than a second threshold and less than a third threshold, and whether the working fluid temperature Q2 is less than or equal to the second threshold; If yes, the geothermal device is started, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the outdoor pipeline of the heat collection unit; Determine whether the working fluid temperature Q1 is less than or equal to a second threshold, and whether the working fluid temperature Q2 is less than or equal to a second threshold; If so, the geothermal device is started, and the working fluid in the geothermal device circulates or indirectly exchanges heat with the working fluid in the collector and the working fluid in the outdoor part pipeline in the heat collection unit.

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