A pressurized cold storage device and method

Abstract

The present invention relates to a pressurized cold storage device, comprising a cryogenic storage tank, a liquid pump, an energy storage tank, a first heater, a second heater and a third heater; the cryogenic storage tank is used to store a fluid working medium, the cryogenic storage tank outlet is connected to the liquid pump inlet, and the liquid pump outlet is respectively connected to the second heater and the first heater inlet through a first reversing three-way valve; the outlet of the first heater is respectively connected to the energy storage tank and one end of the fourth reversing three-way valve through a second reversing three-way valve; the outlet of the second heater is respectively connected to the energy storage tank and the other end of the fourth reversing three-way valve through a third reversing three-way valve; the fourth reversing three-way valve is connected to the third heater inlet, and the third heater outlet is connected to the outside world; wherein, pressure gauges, flow meters and thermometers are provided on the pipelines at both ends of the energy storage tank. The present invention also relates to a pressurized cold storage method, which can effectively improve the efficiency of the cold storage tank and realize efficient storage and recycling of cold energy.

Description

Technical Field

[0001] The present invention relates to the field of cold storage technology, and in particular to a pressurized cold storage device and method. Background Art

[0002] In the process of energy conversion, the storage and reuse of cold energy and heat energy become the key to improving energy efficiency. Low-temperature cold energy storage and reuse have important applications in the fields of liquefied air energy storage, liquefied natural gas cycle process and air separation. The main problems currently exist are the inefficiency of the cold energy storage process and the low conversion rate of recycling. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a pressurized cold storage device and method to solve the inefficiency of the cold energy storage process and the low technical problems of conversion for recycling and utilization.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A pressurized cold storage device comprises a low temperature storage tank, a liquid pump, an energy storage tank, a first heater, a second heater and a third heater;

[0006] The cryogenic storage tank is used to store fluid working medium, the outlet of the cryogenic storage tank is connected to the inlet of the liquid pump, and the outlet of the liquid pump is connected to the inlets of the second heater and the first heater respectively through the first reversing three-way valve;

[0007] The outlet of the first heater is connected to the energy storage tank and one end of the fourth reversing three-way valve respectively through the second reversing three-way valve;

[0008] The outlet of the second heater is connected to the energy storage tank and the other end of the fourth reversing three-way valve respectively through the third reversing three-way valve;

[0009] The fourth reversing three-way valve is connected to the inlet of the third heater, and the outlet of the third heater is connected to the outside;

[0010] Among them, pressure gauges, flow meters and thermometers are installed on the pipelines at both ends of the energy storage tank.

[0011] Further technical solutions are:

[0012] The passage connecting the low-temperature storage tank, the liquid pump, the second heater, the energy storage tank, and the first heater in sequence, and the passage connecting the two ends of the energy storage tank form a pressurization system.

[0013] The low-temperature storage tank, the liquid pump, the first heater, the energy storage tank, and the third heater are sequentially connected to form a cold charging system.

[0014] The passage in which the low-temperature storage tank, the liquid pump, the second heater, the energy storage tank, and the third heater are connected in sequence forms a cold release system.

[0015] It also includes a data acquisition module, the signal input end of the data acquisition module is connected to the signal output ends of the pressure meter, flow meter and thermometer respectively.

[0016] A thermometer group is provided in the energy storage tank. The thermometer group includes a plurality of thermometers evenly distributed in the vertical direction and the horizontal direction. The thermometer group is connected to the data acquisition module by signal.

[0017] The first heater, the second heater and the third heater adopt electric heating devices or convection heat exchange structures.

[0018] The energy storage tank is provided with sensible heat material or phase change material.

[0019] A pressurized cold storage method comprises the following steps:

[0020] To turn on the pressurization mode:

[0021] The low-temperature storage tank, the liquid pump, the first reversing three-way valve, the second heater, the third reversing three-way valve, the energy storage tank, the second reversing three-way valve and the first heater are sequentially connected to form a passage, and the pipeline between the third reversing three-way valve, the fourth reversing three-way valve and the second reversing three-way valve is connected to form a pressurization system;

[0022] The liquid nitrogen stored in the cryogenic storage tank is pressurized to above 5 MPa by a cryogenic liquid pump, vaporized and heated to room temperature in the second heater, and then the pressurized fluid circulates through the pipes and equipment of the entire pressurization system;

[0023] Turn on the cold charging mode:

[0024] The low-temperature storage tank, the liquid pump, the first reversing three-way valve, the first heater, the second reversing three-way valve, the energy storage tank, the third reversing three-way valve, the fourth reversing three-way valve and the third heater are sequentially connected into a passage to form a cold charging system;

[0025] The liquid nitrogen stored in the cryogenic tank is pressurized by a cryogenic liquid pump, heated to 80K~250K in the first heater, and then flows into the energy storage tank to store the cold energy therein. The fluid flowing out of the energy storage tank is heated to the discharge temperature by the third heater and finally discharged to the outside. The temperature, pressure and mass flow rate of the working fluid at the inlet and outlet of the energy storage tank are recorded during the cold charging process.

[0026] Turn on the cooling mode:

[0027] The low temperature storage tank, the liquid pump, the first reversing three-way valve, the second heater, the third reversing three-way valve, the energy storage tank, the second reversing three-way valve, the fourth reversing three-way valve and the third heater are sequentially connected into a passage to form a cold release system;

[0028] The liquid nitrogen stored in the cryogenic tank is pressurized by a cryogenic liquid pump, vaporized and heated to room temperature in the second heater, and then flows into the energy storage tank to absorb the cold therein. The cold fluid flowing out of the energy storage tank is heated to the discharge temperature by the third heater and finally discharged to the outside. The temperature, pressure and mass flow rate of the working fluid at the inlet and outlet of the energy storage tank are recorded during the cold release process.

[0029] The beneficial effects of the present invention are as follows:

[0030] The present invention adopts a pressurized method to store low-temperature cold energy, which can effectively improve the cold storage tank. Efficiency, achieving efficient storage and recycling of cold energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0032] Figure 2 It is a schematic diagram of the pressurization mode of the present invention.

[0033] Figure 3 It is a schematic diagram of the cold charging mode of the present invention.

[0034] Figure 4 It is a schematic diagram of the cooling mode of the present invention.

[0035] In the figure: 100, low-temperature storage tank; 200, liquid pump; 301, first reversing three-way valve; 302, second reversing three-way valve; 303, third reversing three-way valve; 304, fourth reversing three-way valve; 401, first heater; 402, second heater; 403, third heater; 501, first flow meter; 502, second flow meter; 601, first pressure gauge; 602, second pressure gauge; 700, thermometer group; 701, first thermometer; 702, second thermometer; 800, energy storage tank; 900, data acquisition module. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is described below with reference to the accompanying drawings.

[0037] The pressurized cold storage device of this embodiment, such as Figure 1 As shown, it includes a low-temperature storage tank 100, a liquid pump 200, an energy storage tank 800, a first heater 401, a second heater 402 and a third heater 403;

[0038] The cryogenic storage tank 100 is used to store fluid working medium. The outlet of the cryogenic storage tank 100 is connected to the inlet of the liquid pump 200. The outlet of the liquid pump 200 is connected to the inlets of the second heater 402 and the first heater 401 respectively through the first reversing three-way valve 301.

[0039] The outlet of the first heater 401 is connected to the energy storage tank 800 and one end of the fourth reversing three-way valve 304 respectively through the second reversing three-way valve 302;

[0040] The outlet of the second heater 402 is connected to the energy storage tank 800 and the other end of the fourth reversing three-way valve 304 respectively through the third reversing three-way valve 303;

[0041] The fourth reversing three-way valve 304 is connected to the inlet of the third heater 403 , and the outlet of the third heater 403 is connected to the outside.

[0042] Among them, pressure gauges, flow meters and thermometers are installed on the pipelines at both ends of the energy storage tank 800.

[0043] Specifically, Figure 1 As shown, the upper input end of the second flowmeter 502 is connected to the lower output end of the third reversing three-way valve 303; the upper input end of the second pressure gauge 602 is connected to the lower output end of the second flowmeter 502; the second thermometer 702 is located in the pipeline between the second flowmeter 502 and the second pressure gauge 602; the upper input end of the energy storage tank 800 is connected to the lower output end of the second pressure gauge 602; the upper input end of the first pressure gauge 601 is connected to the lower output end of the energy storage tank 800; the upper input end of the first flowmeter 501 is connected to the lower output end of the first pressure gauge 601; the first thermometer 701 is located in the pipeline between the first flowmeter 501 and the first pressure gauge 601;

[0044] The upper input end of the second reversing three-way valve 302 is connected to the lower output end of the first flowmeter 501; the lower input end of the fourth reversing three-way valve 304 is connected to the right output end of the second reversing three-way valve 302; the left input end of the third heater 403 is connected to the right output end of the fourth reversing three-way valve 304, and the right output end is connected to the outside.

[0045] like Figure 2 As shown, the low-temperature storage tank 100, the liquid pump 200, the second heater 402, the energy storage tank 800, the passage connecting the first heater 401 in sequence, and the passage connecting the two ends of the energy storage tank 800 form a pressurization system.

[0046] like Figure 3 As shown, the low-temperature storage tank 100, the liquid pump 200, the first heater 401, the energy storage tank 800, and the third heater 403 are sequentially connected to form a cold charging system.

[0047] like Figure 4 As shown, the low-temperature storage tank 100, the liquid pump 200, the second heater 402, the energy storage tank 800, and the third heater 403 are sequentially connected to form a cold release system.

[0048] The first heater 401 , the second heater 402 , and the third heater 403 are electric heating devices or convection heat exchange structures.

[0049] Specifically, each heater may use a different heating medium to heat the cold fluid (the working fluid stored in the low-temperature storage tank 800) circulating in the heating device. The initial temperature of the heating medium is generally room temperature, and air or water may be used.

[0050] like Figure 1 As shown, it also includes a data acquisition module 900, the signal input end of the data acquisition module 900 is respectively connected to the signal output end of the pressure meter, flow meter and thermometer, and is used to record the dynamic changes of temperature, pressure and mass flow rate during the cold charging process.

[0051] Specifically, the energy storage material contained in the energy storage tank 800 can be a single type, a mixture of multiple materials, or multiple materials stacked in stages in the tank body; the energy storage material itself comes from nature or is obtained through preparation, and can be a sensible heat material or a phase change material.

[0052] Specifically, the energy storage tank 800 can be spherical, cylindrical, shell and tube, parallel plate, irregular or other forms, and the tank body is wrapped with special insulation materials or insulated by vacuum insulation; the tank body is designed to facilitate the removal of energy storage materials, and special welding and sealing techniques are used to achieve the purpose of safe high-pressure cold storage.

[0053] A thermometer group 700 is provided in the energy storage tank 800 . The thermometer group 700 includes a plurality of thermometers evenly distributed in the vertical direction and the horizontal direction. The thermometer group 700 is connected to the data acquisition module 900 by signal.

[0054] Specifically, seven measuring points are evenly arranged at the central vertical position from the beginning to the end of the energy storage tank 800 to measure and record the vertical change of the temperature inside the tank; five measuring points are evenly arranged horizontally on the diameter line where the 3rd and 5th measuring points are located in the middle to measure and record the real-time change of the temperature inside the tank.

[0055] The pressurized cold storage method of this embodiment comprises the following steps:

[0056] To turn on the pressurization mode:

[0057] The left and upper ports of the first reversing three-way valve 301 are opened, the port of the second reversing three-way valve 302 is fully opened, the port of the third reversing three-way valve 303 is fully opened, and the upper and lower ports of the fourth reversing three-way valve 304 are opened, so that the low-temperature storage tank 100, the liquid pump 200, the first reversing three-way valve 301, the second heater 402, the third reversing three-way valve 303, the energy storage tank 800, the second reversing three-way valve 302 and the first heater 401 are sequentially connected to form a passage, and the pipeline between the third reversing three-way valve 303, the fourth reversing three-way valve 304 and the second reversing three-way valve 302 is connected to form a pressurization system;

[0058] And the passage between the fourth reversing three-way valve 304 and the third heater 403 is cut off;

[0059] Pressurization process reference Figure 2 As shown, the liquid nitrogen stored in the cryogenic storage tank 100 is pressurized to a pressure higher than 5 MPa by the cryogenic liquid pump 200, vaporized and heated to room temperature (generally around 293 K) in the second heater 402, and then the pressurized fluid flows through the pipes and equipment of the entire pressurization system, that is, at this time, the pressure of the entire pipe and equipment is maintained at around 5 MPa;

[0060] Among them, it is finally determined by the pressure gauge reading that the pressure in the device reaches the specified pressure;

[0061] Turn on the cold charging mode:

[0062] The left and right ports of the first reversing three-way valve 301 are opened, the left and upper ports of the second reversing three-way valve 302 are opened, the lower and right ports of the third reversing three-way valve 303 are opened, and the upper and right ports of the fourth reversing three-way valve 304 are opened, so that the low-temperature storage tank 100, the liquid pump 200, the first reversing three-way valve 301, the first heater 401, the second reversing three-way valve 302, the energy storage tank 800, the third reversing three-way valve 303, the fourth reversing three-way valve 304 and the third heater 403 are sequentially connected into a passage to form a cold charging system;

[0063] Furthermore, the passages between the first reversing three-way valve 301 and the second heater 402 and between the second heater 402 and the third reversing three-way valve 303 are cut off.

[0064] Reference for the cold charging process Figure 3 As shown, the liquid nitrogen stored in the cryogenic storage tank 100 is pressurized by the cryogenic liquid pump 200, heated to 80K-250K in the first heater 401, and then flows into the energy storage tank 800 to store the cold energy therein, and the fluid flowing out of the energy storage tank 800 is heated to the discharge temperature by the third heater 403 and finally discharged to the outside;

[0065] The data acquisition module 900 records the dynamic changes of the temperature, pressure and mass flow rate of the inlet and outlet working fluids of the energy storage tank 800 during the cold charging process;

[0066] Turn on the cooling mode:

[0067] The left and upper ports of the first reversing three-way valve 301 are opened, the right and upper ports of the second reversing three-way valve 302 are opened, the lower and left ports of the third reversing three-way valve 303 are opened, and the lower and right ports of the fourth reversing three-way valve 304 are opened, so that the low-temperature storage tank 100, the liquid pump 200, the first reversing three-way valve 301, the second heater 402, the third reversing three-way valve 303, the energy storage tank 800, the second reversing three-way valve 302, the fourth reversing three-way valve 304 and the third heater 403 are sequentially connected into a passage to form a cold release system;

[0068] Furthermore, the passage between the second heater 402 and the first and second three-way reversing valves 301 and 302 and the passage between the third and fourth three-way reversing valves 303 and 304 are cut off.

[0069] Cooling process reference Figure 4 As shown, the liquid nitrogen stored in the cryogenic storage tank 100 is pressurized by the cryogenic liquid pump 200, vaporized and heated to room temperature in the second heater 402, and then flows into the energy storage tank 800 to absorb the cold therein. The cold fluid flowing out of the energy storage tank 800 is heated to the discharge temperature by the third heater 403 and finally discharged to the outside;

[0070] The data acquisition module 900 records the dynamic changes in the temperature, pressure and mass flow of the inlet and outlet working fluids of the energy storage tank 800 during the cooling process.

[0071] The operating status of valves and measuring devices in each mode is shown in Table 1.

[0072] Table 1 - Operation status of valves and measuring devices in three modes

[0073]

[0074]

[0075] In the pressurized cold storage method of this embodiment, the cold storage (cold charging) pressure can be adjusted through the pressurization process. Once the pressure gauge reading shows that it has reached the expected value, the pressurization process is stopped. The gas source required for the pressurization process can come from the nitrogen after the liquid nitrogen is vaporized, or from other gases.

[0076] The heating purpose of the third heater 403 is to increase the discharge temperature of the working fluid and ensure safety.

[0077] Among them, the fourth reversing three-way valve 304 is preferably an automatic control valve, which adjusts the size of the valve opening according to the fluctuation of the pressure gauge detection data during the charging and releasing process to ensure that the pressure remains stable during the charging and releasing process.

[0078] In order to further illustrate the effect of the pressurized cold storage method of the present application, Figure 1 The device shown in the figure is simulated and calculated, using a 0.6m diameter and 1.5m high energy storage tank to store cold, filled with pebbles with a diameter of about 0.02m, and a 0.1m thick perlite insulation material attached to the outside. Nitrogen is used as the fluid.

[0079] Calculate the ratio of fluid working medium

[0080] e=(h-h0)-T0(s-s0)

[0081] In the above formula, h is the specific enthalpy of the fluid J / kg, s is the specific entropy of the fluid J / (kg·K), T is the temperature, unit K; the subscript 0 represents the environmental state.

[0082] The system stores cold The efficiency η is the total cooling released during the cooling process. Divide by the total cold storage during the cold charging process

[0083]

[0084] In the above formula, e1 and e2 are the ratios of the cooling release and cooling charge processes. m1 and m2 are the mass flow rates of the working fluid flowing into the energy storage tank during the cold release process and the mass flow rates of the working fluid flowing out of the energy storage tank during the cold charging process, respectively; t dis ,t ch They are respectively the cooling release process time and the cooling charging process time.

[0085] Table 2 shows the cold storage pressure of the system Efficiency comparison table. It can be seen that whether it is supercritical nitrogen (4-10MPa) or non-supercritical nitrogen (0.1-3MPa), as the pressure increases, the system storage The efficiency gradually increases. This shows that pressurization is beneficial to improve cold storage efficiency.

[0086] Table 2 - Cold storage pressure Efficiency Impact Comparison Table

[0087]

[0088] Utilizing the pressurized cold storage device of the present application, the equipment components are designed with detachable modular assembly, and the control variable method can be used to study the influence of various factors on the cold storage results of the device. The variables can be working fluid flow, working pressure, energy storage materials, tanks, tank insulation materials, cryogenic fluids, low-temperature fluid working fluid heating method temperature, logical control strategy, etc. Among them, the working fluid flow and working pressure can be controlled by a variable frequency cryogenic liquid pump, the energy storage materials, tank insulation materials, and cryogenic fluid types can be determined according to specific circumstances, and the energy storage materials and tank sizes can also be replaced according to specific circumstances; the first heater can heat the fluid temperature to a specified temperature (generally 80K~250K), and the second heater heats the fluid temperature to near room temperature (about 293K).

Claims

1. A pressurized cold storage device, characterized in that: It includes a low-temperature storage tank (100), a liquid pump (200), an energy storage tank (800), a first heater (401), a second heater (402) and a third heater (403); The low-temperature storage tank (100) is used to store a fluid working medium, the outlet of the low-temperature storage tank (100) is connected to the inlet of the liquid pump (200), and the outlet of the liquid pump (200) is respectively connected to the inlets of the second heater (402) and the first heater (401) through a first reversing three-way valve (301); The outlet of the first heater (401) is connected to the energy storage tank (800) and one end of the fourth reversing three-way valve (304) respectively through the second reversing three-way valve (302); The outlet of the second heater (402) is connected to the energy storage tank (800) and the other end of the fourth reversing three-way valve (304) respectively through the third reversing three-way valve (303); The fourth reversing three-way valve (304) is connected to the inlet of the third heater (403), and the outlet of the third heater (403) is connected to the outside; Wherein, pressure gauges, flow meters and thermometers are provided on the pipelines at both ends of the energy storage tank (800).

2. The pressurized cold storage device according to claim 1, characterized in that: The passage connecting the low-temperature storage tank (100), the liquid pump (200), the second heater (402), the energy storage tank (800), and the first heater (401) in sequence, and the passage connecting the two ends of the energy storage tank (800) form a pressurization system.

3. The pressurized cold storage device according to claim 2, characterized in that: The low-temperature storage tank (100), the liquid pump (200), the first heater (401), the energy storage tank (800), and the third heater (403) are sequentially connected to form a cold charging system.

4. The pressurized cold storage device according to claim 3, characterized in that: The low-temperature storage tank (100), the liquid pump (200), the second heater (402), the energy storage tank (800), and the third heater (403) are sequentially connected to form a cold release system.

5. The pressurized cold storage device according to claim 1, characterized in that: It also comprises a data acquisition module (900), the signal input end of the data acquisition module (900) being respectively connected to the signal output ends of the pressure meter, the flow meter and the thermometer.

6. The pressurized cold storage device according to claim 5, characterized in that: The energy storage tank (800) is provided with a thermometer group (700), the thermometer group (700) comprising a plurality of thermometers evenly distributed in the vertical direction and the horizontal direction, and the thermometer group (700) is signal-connected to the data acquisition module (900).

7. The pressurized cold storage device according to claim 1, characterized in that: The first heater (401), the second heater (402) and the third heater (403) are electric heating devices or convection heat exchange structures.

8. The pressurized cold storage device according to claim 1, characterized in that: The energy storage tank (800) is provided with a sensible heat material or a phase change material.

9. A pressurized cold storage method, characterized in that: The following steps are involved: To turn on the pressurization mode: The low-temperature storage tank (100), the liquid pump (200), the first reversing three-way valve (301), the second heater (402), the third reversing three-way valve (303), the energy storage tank (800), the second reversing three-way valve (302) and the first heater (401) are sequentially connected to form a passage, and the pipelines between the third reversing three-way valve (303), the fourth reversing three-way valve (304) and the second reversing three-way valve (302) are connected to form a pressurization system; The liquid nitrogen stored in the cryogenic storage tank (100) is pressurized to a value higher than 5 MPa by a cryogenic liquid pump (200), vaporized and heated to room temperature in a second heater (402), and then the pressurized fluid circulates through the pipes and equipment of the entire pressurization system; Turn on the cold charging mode: The low-temperature storage tank (100), the liquid pump (200), the first reversing three-way valve (301), the first heater (401), the second reversing three-way valve (302), the energy storage tank (800), the third reversing three-way valve (303), the fourth reversing three-way valve (304) and the third heater (403) are sequentially connected to form a passage to form a cold charging system; The liquid nitrogen stored in the cryogenic storage tank (100) is pressurized by a cryogenic liquid pump (200), heated to 80K to 250K in a first heater (401), and then flows into the energy storage tank (800) to store cold energy therein. The fluid flowing out of the energy storage tank (800) is heated to a discharge temperature by a third heater (403) and finally discharged to the outside. The temperature, pressure and mass flow rate of the inlet and outlet working fluids of the energy storage tank (800) are recorded during the cold charging process. Turn on the cooling mode: The low-temperature storage tank (100), the liquid pump (200), the first reversing three-way valve (301), the second heater (402), the third reversing three-way valve (303), the energy storage tank (800), the second reversing three-way valve (302), the fourth reversing three-way valve (304) and the third heater (403) are sequentially connected to form a passage to form a cold release system; The liquid nitrogen stored in the cryogenic storage tank (100) is pressurized by a cryogenic liquid pump (200), vaporized and heated to room temperature in the second heater (402), and then flows into the energy storage tank (800) to absorb the cold therein. The cold fluid flowing out of the energy storage tank (800) is heated to the discharge temperature by the third heater (403) and finally discharged to the outside. The temperature, pressure and mass flow rate of the inlet and outlet working fluids of the energy storage tank (800) are recorded during the cold release process.

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