An underground low-temperature storage tank surrounding soil heating system based on temperature compensation

Abstract

The present invention discloses a soil heating system around an underground cryogenic storage tank based on temperature compensation, comprising: a ground source heat subsystem including an evaporating pipe and a condensing pipe; the evaporating pipe is arranged inside the wall of an underground granary; the condensing pipe is arranged on the periphery of the soil around the underground cryogenic storage tank; a connecting main pipe connects the evaporating pipe and the condensing pipe; a phase change material enters the evaporating pipe through the connecting main pipe to exchange heat with the underground granary; the heated phase change material then enters the condensing pipe through the first path of the connecting main pipe to exchange heat with the soil around the underground cryogenic storage tank; the cooled phase change material enters the evaporating pipe through the second path of the connecting main pipe to form a circulating system; a central control subsystem is arranged on the connecting main pipe; a temperature sensor in the central control subsystem is used to detect the water temperature in the connecting main pipe to control the operation degree of the system. By this method, on the basis of reducing the internal temperature of the underground granary, the purpose of heating the soil around the underground cryogenic storage tank can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of ground source heat pumps, and particularly relates to a soil heating system around an underground low-temperature storage tank based on temperature compensation. Background Art

[0002] With the accelerating urbanization process and increasing population nowadays, the demand for energy in urban construction and development is also growing. Obviously, the demand for energy storage devices is also increasing. Due to the shortage of urban land resources, the role of underground low-temperature storage tanks in the field of energy storage is becoming more and more obvious.

[0003] Underground low-temperature storage tanks for storing energy such as liquefied natural gas often operate in a low-temperature and high-pressure working environment. For example, storing liquefied natural gas requires an environment of more than -160 °C. Since the medium around the underground low-temperature storage tank is complex geotechnical medium, and under the action of low temperature, the water in the geotechnical medium is prone to frost heaving and other situations, which will have an adverse impact on the underground low-temperature storage tank.

[0004] At present, the existing anti-freezing methods for the soil around underground low-temperature storage tanks usually adopt the form of electric heating rods. Electric heating rods are arranged around and at the bottom of the underground low-temperature storage tank to heat the soil around the underground low-temperature storage tank. Although the use of electric heating rods achieves the effect of heating the soil, the utilization rate of converting electrical energy into heat energy is not high, the soil is heated unevenly, the heating effect is not very ideal, and at the same time, a great deal of energy is wasted.

[0005] Nowadays, cities are getting bigger and the urban population is also increasing. Along with the COVID-19 pandemic in recent years, each city should have its own strategic reserves, and the construction of granaries is urgent. For a city, the space required for granaries is huge, and the limited above-ground space is used for other purposes. Therefore, more underground granaries have become the only choice.

[0006] Underground granaries have excellent performance such as low temperature, low oxygen, heat insulation, moisture proof, airtightness, easy management, and suitable for mechanized operation of grain in and out of the warehouse. They are the most suitable type of granary for long-term storage of grain, which is both economical and environmentally friendly. Grain is a living thing. The temperature difference in underground granaries is small, and it remains at 13 to 19 °C all year round. The respiration of grain is weak and the nutrient consumption is small. If the temperature of the granary can be further reduced, the nutrient consumption of the grain will be further reduced, thus ensuring better quality of the grain.

[0007] Therefore, how to achieve the purpose of reducing the internal temperature of the underground granary and overcome the problems of low energy conversion rate and uneven soil heating caused by using electric heating rods in the prior art has become the key issue in current research. Summary of the Invention

[0008] In view of the above problems, the present invention provides a soil heating system around an underground low-temperature storage tank based on temperature compensation, which can at least solve some of the above technical problems. By this method, on the basis of reducing the temperature inside the underground granary, the purpose of heating the soil around the underground low-temperature storage tank can be achieved, and the energy conversion rate and utilization rate are improved during this cycle process.

[0009] An embodiment of the present invention provides a soil heating system around an underground low-temperature storage tank based on temperature compensation, including: a ground source heat subsystem, a phase change material, a connecting main pipe (5), and a central control subsystem (27);

[0010] The ground source heat subsystem includes an evaporator pipe (2) and a condenser pipe (16); the evaporator pipe (2) is arranged inside the wall of the underground granary (1); the condenser pipe (16) is arranged on the periphery of the soil around the underground low-temperature storage tank (17);

[0011] The connecting main pipe (5) connects the evaporator pipe (2) and the condenser pipe (16);

[0012] The phase change material enters the evaporator pipe (2) through the connecting main pipe (5) and exchanges heat with the underground granary (1); the heated phase change material then enters the condenser pipe (16) through the first path of the connecting main pipe (5) and exchanges heat with the soil around the underground low-temperature storage tank (17); the cooled phase change material enters the evaporator pipe (2) through the second path of the connecting main pipe (5) to form a circulation system;

[0013] The central control subsystem (27) is arranged on the connecting main pipe (5); the temperature sensor (28) in the central control subsystem (27) is used to detect the temperature of the phase change material in the connecting main pipe (5) to control the operation degree of the system.

[0014] Further, the central control subsystem (27) further includes a heat storage device (29);

[0015] When the energy demands of the underground granary (1) and the soil around the underground low-temperature storage tank (17) do not match, the excess energy is stored in the heat storage device (29).

[0016] Further, a first water stop valve (3) and a second water stop valve (4) are respectively arranged at the connecting main pipe (5) at both ends of the underground granary (1).

[0017] Further, a buried pipe (6) is connected in parallel at the connecting main pipe (5) at both ends of the underground granary (1).

[0018] Further, the condenser pipe (16) is arranged on the periphery of the soil around the underground low-temperature storage tank (17) in a diagonal 45° circular arrangement.

[0019] Further, third water stop valves (15) and fourth water stop valves (18) are respectively arranged at two ends of the condenser pipe (16).

[0020] Further, the ground source heat subsystem further includes a first water pump (8), a water extraction pipe (7), a hot water tank (11) and a scroll compressor (13);

[0021] The hot water tank (11) is arranged on the first path of the connecting main pipe (5);

[0022] The scroll compressor (13) is connected in parallel to the first path of the connecting main pipe (5) through a fifth water stop valve (12) and a sixth water stop valve (14);

[0023] The water extraction pipe (7) is arranged in the bored cast-in-place pile of the underground granary (1) and is connected to the hot water tank (11);

[0024] The first water pump (8) is arranged on the water extraction pipe (7); and the first water pump (8) is connected to the central control subsystem (27) for control connection;

[0025] Under the action of the first water pump (8), the water extraction pipe (7) extracts groundwater and stores it in the hot water tank (11) for heating the phase change material; the heated phase change material flows through the condenser pipe (16) after being heated again by the scroll compressor (13) to heat the soil around the underground low-temperature storage tank (17).

[0026] Further, the ground source heat subsystem further includes a cold water tank (19) and an expansion valve (25);

[0027] The cold water tank (19) is arranged on the second path of the connecting main pipe (5) and is connected to the water extraction pipe (7);

[0028] The expansion valve (25) is connected in parallel to the second path of the connecting main pipe (5) through a seventh water stop valve (24) and an eighth water stop valve (26);

[0029] Under the action of the first water pump (8), the water extraction pipe (7) extracts groundwater and stores it in the cold water tank (19) for cooling the phase change material; the cooled phase change material flows through the evaporation pipe (2) after being cooled again by the expansion valve (25) to cool the underground granary (1).

[0030] Further, the ground source heat subsystem further includes a second water pump (22) and a water outlet pipe (23);

[0031] The outlet pipe (23) is arranged in the bored cast-in-place pile of the underground granary (1) and is respectively connected to the hot water tank (11) and the cold water tank (19);

[0032] The second water pump (22) is arranged on the outlet pipe (23); and the second water pump (22) is connected to the central control subsystem (27) for control;

[0033] Under the action of the second water pump (22), the outlet pipe (23) pumps out the groundwater in the hot water tank (11) or the cold water tank (19) and makes it flow back underground again.

[0034] Furthermore, a ninth water stop valve (9), a tenth water stop valve (10), an eleventh water stop valve (20) and a twelfth water stop valve (21) are respectively arranged at the water extraction pipe (7), the hot water tank (11), the cold water tank (19) and the outlet pipe (23).

[0035] Compared with the prior art, a soil heating system around an underground low-temperature storage tank based on temperature compensation recorded in the present invention has the following beneficial effects:

[0036] 1. The evaporation pipe and the condensation pipe and the connecting main pipe form a closed circulation system. On the basis of reducing the internal temperature of the underground granary, the purpose of heating the soil around the underground low-temperature storage tank is achieved, and the energy conversion rate and utilization rate are improved in this circulation process.

[0037] 2. The central control subsystem connected to the connecting main pipe in the present invention can accurately control the temperature of the soil around the underground low-temperature storage tank and the underground granary, and store the excess heat at the same time.

[0038] 3. In the present invention, by arranging the condensation pipe in a diagonal 45° circular arrangement around the periphery of the soil around the underground low-temperature storage tank, it can ensure uniform heating of the soil, and overcome the problems of low energy conversion rate and uneven heating of the soil caused by using electric heating rods in the prior art.

[0039] 4. If the energy of the system circulation is not enough, the ground source heat pump system is started, and groundwater is extracted by the first water pump to provide energy for the system and utilize the energy in the underground soil; in this way, it not only plays a role in reducing the temperature of the underground granary, but also can heat the soil around the underground low-temperature storage tank, and also saves energy.

[0040] Other features and advantages of the present invention will be described in the following description, and part of them will be obvious from the description, or understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the written description, claims and drawings.

[0041] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0042] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0043] Figure 1 It is a schematic structural diagram of the soil heating system around an underground low-temperature storage tank based on temperature compensation provided by an embodiment of the present invention.

[0044] Figure 2 It is a top view sectional schematic diagram of the central control subsystem provided by an embodiment of the present invention.

[0045] Figure 3 It is a top view sectional schematic diagram of a hot water tank or a cold water tank provided by an embodiment of the present invention.

[0046] Figure 4 It is a front view sectional schematic diagram of the hot water tank provided by an embodiment of the present invention.

[0047] Figure 5 It is a front view sectional schematic diagram of the cold water tank provided by an embodiment of the present invention.

[0048] Figure 6 It is a side view sectional schematic diagram of the cold water tank provided by an embodiment of the present invention.

[0049] In the figure: 1 - underground granary; 2 - evaporation pipe; 3 - first water stop valve; 4 - second water stop valve; 5 - connecting main pipe; 6 - buried pipe; 7 - water extraction pipe; 8 - first water pump; 9 - ninth water stop valve; 10 - tenth water stop valve; 11 - hot water tank; 12 - fifth water stop valve; 13 - scroll compressor; 14 - sixth water stop valve; 15 - third water stop valve; 16 - condensing pipe; 17 - underground low-temperature storage tank; 18 - fourth water stop valve; 19 - cold water tank; 20 - eleventh water stop valve; 21 - twelfth water stop valve; 22 - second water pump; 23 - water outlet pipe; 24 - seventh water stop valve; 25 - expansion valve; 26 - eighth water stop valve; 27 - central control subsystem; 28 - temperature sensor; 29 - heat accumulator. Detailed Embodiments

[0050] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art.

[0051] See Figure 1As shown in the figure, an embodiment of the present invention provides a soil heating system around an underground cryogenic storage tank based on temperature compensation, including: a ground source heat subsystem, a phase change material, a connection main pipe 5, and a central control subsystem 27; wherein, the ground source heat subsystem includes an evaporation pipe 2 and a condensation pipe 16; the evaporation pipe 2 is arranged inside the wall of the underground granary 1; the condensation pipe 16 is arranged on the periphery of the soil around the underground cryogenic storage tank 17; the connection main pipe 5 connects the evaporation pipe 2 and the condensation pipe 16;

[0052] When the system is operating, the circulating phase change material enters the evaporation pipe 2 through the connection main pipe 5 and exchanges heat with the underground granary 1; the phase change material absorbs the temperature of the surrounding environment of the underground granary 1 and then its temperature rises, while the surrounding environment temperature decreases; the phase change material with increased temperature then enters the condensation pipe 16 through the first path of the connection main pipe 5 and exchanges heat with the soil around the underground cryogenic storage tank 17. At this time, the surrounding soil absorbs the heat of the phase change material and its temperature rises, and the phase change material in the condensation pipe 16 releases heat and its temperature decreases; the cooled phase change material then enters the evaporation pipe 2 through the second path of the connection main pipe 5, forming a circulating system; the central control subsystem 27 is arranged on the connection main pipe 5; the central control subsystem 27 detects the temperature of the phase change material in the connection main pipe 5 through a temperature sensor 28 to control the operation degree of the system; for example, when the temperature of the phase change material is too high and it is insufficient to cool the underground granary 1, the central control subsystem 27 controls to close the second water stop valve 4 so that the phase change material does not affect the temperature of the underground granary 1.

[0053] In another embodiment, refer to Figure 2 As shown in the figure, the central control subsystem 27 further includes a heat storage device 29; when the energy demands of the soil around the underground granary 1 and the underground cryogenic storage tank 17 do not match, the excess energy is stored in the heat storage device 29.

[0054] In another embodiment, refer to Figure 1 As shown in the figure, a first water stop valve 3 and a second water stop valve 4 are respectively provided at the connection main pipe 5 at both ends of the underground granary 1; the cooling condition of the underground granary 1 is controlled through the first water stop valve 3 and the second water stop valve 4 to achieve the best cooling effect and the purpose of saving energy.

[0055] In another embodiment, refer to Figure 1 As shown in the figure, buried pipes 6 are arranged in parallel at the connection main pipe 5 at both ends of the underground granary 1; the buried pipes 6 are used to divert the excess cold energy leading to the underground granary 1 to control the temperature of the underground granary 1.

[0056] In another embodiment, refer to Figure 1 As shown in the figure, the condensation pipe 16 is arranged on the periphery of the soil around the underground cryogenic storage tank 17 in a diagonal 45° circular arrangement manner so that the soil can be heated evenly.

[0057] In another embodiment, refer to Figure 1 As shown, third water stop valves 15 and fourth water stop valves 18 are respectively provided at both ends of the condenser pipe 16; whether to heat the soil around the underground low-temperature storage tank 17 is controlled by the third water stop valve 15 and the fourth water stop valve 18, so as to achieve the best heating effect and save energy.

[0058] In another embodiment, the phase change material uses the refrigerant R417a.

[0059] In another embodiment, refer to Figures 3 - 6 As shown, the ground source heat subsystem further includes a first water pump 8, a water extraction pipe 7, a hot water pool 11 and a scroll compressor 13; wherein, the hot water pool 11 is arranged on the first path of the connecting main pipe 5; the scroll compressor 13 is connected in parallel to the first path of the connecting main pipe 5 through a fifth water stop valve 12 and a sixth water stop valve 14; the water extraction pipe 7 is arranged in the bored cast-in-place pile of the underground granary 1 and is connected to the hot water pool 11; the first water pump 8 is arranged on the water extraction pipe 7, and the first water pump 8 is controlled and connected to the central control subsystem 27;

[0060] The ground source heat subsystem further includes a cold water pool 19 and an expansion valve 25; wherein the cold water pool 19 is arranged on the second path of the connecting main pipe 5 and is connected to the water extraction pipe 7; the expansion valve 25 is connected in parallel to the second path of the connecting main pipe 5 through a seventh water stop valve 24 and an eighth water stop valve 26;

[0061] The ground source heat subsystem further includes a second water pump 22 and a water outlet pipe 23; wherein the water outlet pipe 23 is arranged in the bored cast-in-place pile of the underground granary 1 and is respectively connected to the hot water pool 11 and the cold water pool 19; the second water pump 22 is arranged on the water outlet pipe 23, and the second water pump 22 is controlled and connected to the central control subsystem 27;

[0062] A ninth water stop valve 9, a tenth water stop valve 10, an eleventh water stop valve 20 and a twelfth water stop valve 21 are respectively provided at the above-mentioned water extraction pipe 7, hot water pool 11, cold water pool 19 and water outlet pipe 23; the ninth water stop valve 9, the tenth water stop valve 10, the eleventh water stop valve 20 and the twelfth water stop valve 21 jointly control the flow direction of the groundwater extracted by the first water pump 8 through the water extraction pipe 7 to ensure that the groundwater enters the correct water pool;

[0063] For example, in winter, when the heat for heating the soil around the underground low-temperature storage tank 17 is insufficient, the first water pump 8 is started through the central control subsystem 27. At this time, the ninth water stop valve 9 and the tenth water stop valve 10 are opened, and the eleventh water stop valve 20 and the twelfth water stop valve 21 are closed; under the action of the first water pump 8, the water extraction pipe 7 extracts groundwater and stores it in the hot water pool 11 for heating the phase change material; the heated phase change material flows through the condenser pipe 16 again after being heated by the scroll compressor 13 to heat the soil around the underground low-temperature storage tank 17.

[0064] For example, in summer, when the cooling capacity required for the underground granary 1 is insufficient, the first water pump 8 is started through the central control subsystem 27. At this time, the ninth water stop valve 9 and the eleventh water stop valve 20 are opened, and the tenth water stop valve 10 and the twelfth water stop valve 21 are closed; the water suction pipe 7 extracts groundwater and stores it in the cold water tank 19 for cooling the phase change material; the cooled phase change material flows through the evaporation pipe 2 after being cooled again by the expansion valve 25 to cool the underground granary 1.

[0065] When groundwater is not needed, under the action of the second water pump 22, the water outlet pipe 23 pumps out the groundwater in the hot water tank 11 or the cold water tank 19 to make it flow back underground again.

[0066] The embodiment of the present invention provides a soil heating system around an underground low-temperature storage tank based on temperature compensation. The evaporation pipe 2 and the condensation pipe 16 form a closed circulation system with the connecting main pipe 5. The system uses the phase change material heated after absorbing the cold by the underground granary 1 as a heat source, and transports it to the condensation pipe 16 through the connecting main pipe 5 for heating the soil around the underground low-temperature storage tank; at the same time, the condensation pipe 16 transports the phase change material cooled after heating the soil back to the underground granary through the connecting main pipe 5 again for energy exchange, so as to achieve the purpose of saving energy and improving energy utilization rate; the excess heat can be stored in the heat storage device 29 in the central control subsystem 27; if this cycle cannot meet the demand, the ground source heat pump system is started, and groundwater is extracted through the first water pump 8 to utilize the energy in the underground soil to provide additional energy for the system, and only a little electric energy is needed to drive the operation of the system.

[0067] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A soil heating system around an underground low-temperature storage tank based on temperature compensation, characterized in that, it includes: a ground source heat subsystem, a phase change material, a connecting main pipe (5) and a central control subsystem (27); The ground source heat subsystem includes an evaporation pipe (2) and a condensation pipe (16); the evaporation pipe (2) is arranged inside the wall of the underground granary (1); the condensation pipe (16) is arranged on the periphery of the soil around the underground low-temperature storage tank (17); The connecting main pipe (5) connects the evaporation pipe (2) and the condensation pipe (16); The phase change material enters the evaporation pipe (2) through the connecting main pipe (5) and exchanges heat with the underground granary (1); The heated phase change material then enters the condensation pipe (16) through the first path of the connecting main pipe (5) and exchanges heat with the soil around the underground low-temperature storage tank (17); the cooled phase change material enters the evaporation pipe (2) through the second path of the connecting main pipe (5) to form a circulation system; The central control subsystem (27) is arranged on the connecting main pipe (5); the temperature sensor (28) in the central control subsystem (27) is used to detect the temperature of the phase change material in the connecting main pipe (5) to control the operation degree of the system; The ground source heat subsystem further includes a first water pump (8), a water extraction pipe (7), a hot water pool (11) and a scroll compressor (13); The hot water pool (11) is arranged on the first path of the connecting main pipe (5); The scroll compressor (13) is connected in parallel to the first path of the connecting main pipe (5) through a fifth water stop valve (12) and a sixth water stop valve (14); The water extraction pipe (7) is arranged inside the bored cast-in-place pile of the underground granary (1) and is connected to the hot water pool (11); The first water pump (8) is arranged on the water extraction pipe (7); and the first water pump (8) is controlled and connected to the central control subsystem (27); Under the action of the first water pump (8), the water extraction pipe (7) extracts groundwater and stores it in the hot water pool (11) for heating the phase change material; the heated phase change material is reheated by the scroll compressor (13) and then flows through the condensation pipe (16) to heat the soil around the underground low-temperature storage tank (17).

2. The soil heating system around an underground low-temperature storage tank based on temperature compensation according to claim 1, characterized in that, the central control subsystem (27) further includes a heat storage device (29); When the energy demands of the soil around the underground granary (1) and the underground low-temperature storage tank (17) do not match, the excess energy is stored in the heat storage device (29).

3. The soil heating system around an underground low-temperature storage tank based on temperature compensation according to claim 1, characterized in that, A first water stop valve (3) and a second water stop valve (4) are respectively arranged at the connecting main pipe (5) at both ends of the underground granary (1).

4. The soil heating system around an underground low-temperature storage tank based on temperature compensation according to claim 1, characterized in that, The connection main pipes (5) at both ends of the underground granary (1) are connected in parallel with buried pipes (6).

5. A soil heating system around an underground cryogenic storage tank based on temperature compensation as described in claim 1, characterized in that, the condenser pipes (16) are arranged in an inclined 45° circular layout around the periphery of the soil around the underground cryogenic storage tank (17).

6. A soil heating system around an underground cryogenic storage tank based on temperature compensation as described in claim 1, characterized in that, both ends of the condenser pipe (16) are respectively provided with a third water stop valve (15) and a fourth water stop valve (18).

7. A soil heating system around an underground cryogenic storage tank based on temperature compensation as described in claim 1, characterized in that, the ground source heat subsystem further includes a cold water pool (19) and an expansion valve (25); the cold water pool (19) is arranged on the second path of the connection main pipe (5) and is connected to the water extraction pipe (7); the expansion valve (25) is connected in parallel to the second path of the connection main pipe (5) through a seventh water stop valve (24) and an eighth water stop valve (26); under the action of the first water pump (8), the water extraction pipe (7) extracts groundwater and stores it in the cold water pool (19) for cooling the phase change material; the cooled phase change material flows through the evaporation pipe (2) after being cooled again by the expansion valve (25) to cool the underground granary (1).

8. A soil heating system around an underground cryogenic storage tank based on temperature compensation as described in claim 7, characterized in that, the ground source heat subsystem further includes a second water pump (22) and a water outlet pipe (23); the water outlet pipe (23) is arranged in the bored cast-in-place pile of the underground granary (1) and is respectively connected to the hot water pool (11) and the cold water pool (19); the second water pump (22) is arranged on the water outlet pipe (23); and the second water pump (22) is controlled and connected to the central control subsystem (27); under the action of the second water pump (22), the water outlet pipe (23) pumps out the groundwater in the hot water pool (11) or the cold water pool (19) to make it flow back underground again.

9. A soil heating system around an underground cryogenic storage tank based on temperature compensation as described in claim 8, characterized in that, a ninth water stop valve (9), a tenth water stop valve (10), an eleventh water stop valve (20) and a twelfth water stop valve (21) are respectively provided at the water extraction pipe (7), the hot water pool (11), the cold water pool (19) and the water outlet pipe (23).

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