Liquid nitrogen gasification cooling energy recovery and utilization system and control method thereof

Abstract

The present invention discloses a liquid nitrogen vaporization cold recovery and utilization system and a control method thereof. The system includes a water collector, a water distributor, and a refrigeration unit, a liquid nitrogen unit, and a cold storage unit arranged in parallel between the water collector and the water distributor. The cold storage unit includes a fifth circulating pump, a cold storage tank, and a sixth circulating pump connected in series. One end of the fifth circulating pump is connected to the water collector, and one end of the sixth circulating pump is connected to the water distributor. The present invention utilizes the cold storage unit to recover the cold generated during the liquid nitrogen vaporization process, preferentially using the liquid nitrogen unit and the cold storage unit for cooling, thereby reducing the operating time of the refrigeration unit and achieving energy conservation and emission reduction.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration, and in particular to a liquid nitrogen gasification cold energy recovery and utilization system and a control method thereof. Background Art

[0002] Nitrogen, an inert gas, is widely used in the manufacturing of lithium-ion batteries. Nitrogen is typically stored in liquid nitrogen tanks. During use, liquid nitrogen absorbs heat from the external environment through a vaporizer and is converted into nitrogen. Due to the cryogenic nature of liquid nitrogen, moisture in the air freezes when it comes into contact with the cold surface of the vaporizer. To ensure nitrogen supply in production workshops, liquid nitrogen units are typically equipped with two air-bath vaporizers that operate alternately. Currently, the operating power consumption of the refrigeration units in lithium battery plants is enormous, necessitating the recovery of liquid nitrogen vaporization cooling energy to reduce operating costs.

[0003] Typically, the refrigeration unit is selected based on the cooling needs of the terminal. However, the cooling capacity generated by the liquid nitrogen vaporization process cannot directly match the cooling needs of the terminal. Therefore, it is considered to add a cold storage unit to store the cooling capacity generated by the liquid nitrogen vaporization process and replace the refrigeration unit to provide cooling to the terminal during certain periods of time. Summary of the Invention

[0004] The object of the present invention is to provide a liquid nitrogen vaporization cooling energy recovery and utilization system and a control method thereof, which utilizes a water cold storage unit to recover the liquid nitrogen vaporization cooling energy, thereby reducing the operating power consumption of the refrigeration unit.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention discloses a liquid nitrogen vaporization cold energy recovery and utilization system, comprising a water collector, a water distributor, and a refrigeration unit, a liquid nitrogen unit, and a cold storage unit arranged in parallel between the water collector and the water distributor; the cold storage unit comprises a fifth circulating pump, a cold storage tank, and a sixth circulating pump connected in series, one end of the fifth circulating pump is connected to the water collector, and one end of the sixth circulating pump is connected to the water distributor.

[0007] A further solution is that the refrigeration unit includes a cooling tower, a first circulating pump, a refrigeration main unit and a second throttle valve; the outlet end of the cooling tower is connected to the cooling water inlet end of the refrigeration main unit, the cooling water outlet end of the refrigeration main unit is connected to the first circulating pump, the other end of the first circulating pump is connected to the inlet end of the cooling tower, the water collector is connected to the second circulating pump, the other end of the second circulating pump is connected to the chilled water inlet end of the refrigeration main unit, and the chilled water outlet of the refrigeration main unit is connected to the water distributor.

[0008] In a further embodiment, the liquid nitrogen unit includes a liquid nitrogen tank, a vaporizer, a third circulation pump, a heat exchanger and a fourth circulation pump; the outlet of the liquid nitrogen tank is connected to the liquid nitrogen inlet of the vaporizer, the nitrogen outlet of the vaporizer is connected to the inlet of the workshop nitrogen network through a pipeline, the refrigerant outlet of the vaporizer is connected to the inlet of the third circulation pump, the outlet of the third circulation pump is connected to the first inlet of the heat exchanger, the first outlet of the heat exchanger is connected to the refrigerant inlet of the vaporizer, the outlet of the water collector is connected to the inlet of the fourth circulation pump, the outlet of the fourth circulation pump is connected to the second inlet of the heat exchanger, and the second outlet of the heat exchanger is connected to the inlet of the water separator.

[0009] In a further solution, the cold storage unit also includes a twelfth throttle valve connected in parallel at both ends of the fifth circulation pump, a thirteenth throttle valve connected in parallel at both ends of the sixth circulation pump, an eleventh throttle valve connected in parallel at both ends of the cold storage tank, a fourteenth throttle valve arranged between the water collector and the fifth circulation pump, and a fifteenth throttle valve arranged between the sixth circulation pump and the water distributor.

[0010] In a further solution, the liquid nitrogen unit further includes a seventh throttle valve connected in parallel at both ends of the fourth circulation pump, an eighth throttle valve provided between the fourth circulation pump and the water collector, and a tenth throttle valve provided between the heat exchanger and the water distributor.

[0011] In a further solution, the refrigeration unit also includes a second throttle valve connected in parallel at both ends of the second circulation pump, a first throttle valve connected in series between the first circulation pump and the refrigeration host, a third throttle valve arranged between the second circulation pump and the water collector, and a fifth throttle valve arranged between the heat exchanger and the water distributor.

[0012] A further solution also includes a control module, a first temperature sensor connected in series between the refrigeration main unit and the water distributor, and a fourth throttle valve arranged between the first temperature sensor and the water distributor; it also includes a second temperature sensor arranged between the heat exchanger and the water distributor, and a ninth throttle valve arranged between the second temperature sensor and the water distributor.

[0013] In a second aspect, the present invention discloses a control method for the above-mentioned liquid nitrogen gasification cold energy recovery and utilization system, comprising the following steps:

[0014] Step S101: The control module obtains a cooling demand instruction of a chilled water terminal device;

[0015] Step S102: The control module determines whether the liquid nitrogen unit is working. If the liquid nitrogen unit is working, the process proceeds to step S103; if the liquid nitrogen unit is not working, the process proceeds to step S108.

[0016] Step S103: The control module determines whether the liquid nitrogen unit meets the cooling demand based on the chilled water supply temperature detected by the second temperature sensor. If the liquid nitrogen unit meets the cooling demand, the process proceeds to step S104; if the liquid nitrogen unit does not meet the cooling demand, the process proceeds to step S105.

[0017] Step S104: Execute the independent cooling mode of the liquid nitrogen unit, stop the refrigeration unit and the cold storage unit, and form a passage through the water collector, the fourth circulation pump, the heat exchanger, and the water distributor to realize cooling of the terminal by the liquid nitrogen unit;

[0018] Step S105: The control module determines whether the cold storage unit meets the cooling requirement. If so, the process proceeds to step S106; if not, the process proceeds to step S107.

[0019] Step S106: Execute the liquid nitrogen unit cold storage unit combined cooling mode, the refrigeration unit stops running, the water collector, the fourth circulation pump, the heat exchanger, and the water distributor form a passage, the water collector, the cold storage tank, the sixth circulation pump, and the water distributor form a passage, and the liquid nitrogen unit cold storage unit combines to provide cooling for the terminal;

[0020] Step S107: Execute the refrigeration unit cooling and liquid nitrogen unit cold storage mode. The water collector, the second circulating pump, the refrigeration host, and the water distributor form a passage so that the refrigeration unit can supply cold to the terminal. Meanwhile, the cold storage tank, the fifth circulating pump, the heat exchanger, and the cold storage tank form a passage so that the liquid nitrogen unit can supply cold to the cold storage unit.

[0021] Step S108: The control module determines whether the cold storage unit meets the cooling requirement. If so, the process proceeds to step S109; if not, the process proceeds to step S110.

[0022] Step S109: Execute the independent cooling mode of the cold storage unit, stop the refrigeration unit and the liquid nitrogen unit, and form a passage among the water collector, the cold storage tank, the sixth circulation pump, and the water distributor so that the cold storage unit can provide cooling for the terminal.

[0023] Step S110: Execute the refrigeration unit independent cooling mode, the liquid nitrogen unit and the cold storage unit stop running, the water collector, the second circulation pump, the refrigeration host, and the water distributor form a passage, and the refrigeration unit provides cooling for the terminal.

[0024] In a further solution step S104, when the liquid nitrogen unit independent cooling mode is executed, the control module controls the opening of the sixth throttle valve according to the chilled water temperature detected by the second temperature sensor. When the temperature detected by the second temperature sensor is greater than the set value, the opening of the sixth throttle valve is increased; when the temperature detected by the second temperature sensor is less than the set value, the opening of the sixth throttle valve is reduced.

[0025] In a further solution step S106, when the liquid nitrogen unit cold storage unit combined cooling mode is executed, the control module determines whether the liquid nitrogen unit meets the cooling demand based on the chilled water temperature detected by the second temperature sensor. When the temperature detected by the second temperature sensor is greater than the set value, the power of the fourth circulation pump is reduced and the power of the sixth circulation pump is increased. When the temperature detected by the second temperature sensor is less than the set value, the power of the fourth circulation pump is increased and the power of the sixth circulation pump is reduced.

[0026] In a further scheme step S107, when the refrigeration unit cools and the liquid nitrogen unit stores cold in the cold storage mode, the control module determines whether the refrigeration unit meets the cooling demand based on the chilled water temperature detected by the first temperature sensor. When the temperature detected by the first temperature sensor is greater than the set value, the power of the refrigeration host and the second circulation pump is increased; when the temperature detected by the first temperature sensor is less than the set value, the power of the refrigeration host and the second circulation pump is reduced; the control module determines whether the liquid nitrogen unit meets the cold storage demand based on the chilled water temperature detected by the second temperature sensor. When the temperature detected by the second temperature sensor is greater than the set value, the power of the fifth circulation pump is reduced; when the temperature detected by the second temperature sensor is less than the set value, the power of the fifth circulation pump is increased.

[0027] Further solution: In step S110, when the independent cooling mode of the refrigeration unit is executed, the control module determines whether the refrigeration unit meets the cooling demand based on the chilled water temperature detected by the first temperature sensor. When the temperature detected by the first temperature sensor is greater than the set value, the power of the refrigeration main unit and the second circulation pump is increased; when the temperature detected by the first temperature sensor is less than the set value, the power of the refrigeration main unit and the second circulation pump is reduced.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] By utilizing cold storage units to recover the cooling energy generated during the liquid nitrogen vaporization process, prioritizing the use of liquid nitrogen units and cold storage units for cooling, the operating time of the refrigeration units can be reduced, achieving energy conservation and emission reductions. Compared to directly using the cooling energy generated during the liquid nitrogen vaporization process to pre-cool the chilled water return of the refrigeration unit, the cold storage solution can extend the downtime of the refrigeration unit and avoid frequent startup and shutdown of the refrigeration unit due to load fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure of the liquid nitrogen gasification cooling energy recovery and utilization system of the present invention;

[0031] Figure 2 is a flow chart of the control method of the present invention;

[0032] Figure 3 This is a schematic diagram of the independent cooling mode of the liquid nitrogen unit in the present invention;

[0033] Figure 4This is a schematic diagram of the combined cooling mode of the liquid nitrogen unit and the cold storage unit;

[0034] Figure 5 Schematic diagram of cold storage mode of liquid nitrogen unit supplying cold to refrigeration unit;

[0035] Figure 6 This is a schematic diagram of the independent cooling mode of the cold storage unit;

[0036] Figure 7 This is a schematic diagram of the independent cooling mode of the refrigeration unit;

[0037] In the figure: 101-cooling tower; 102-first circulating pump; 103-first throttle valve; 104-refrigeration main unit; 105-second circulating pump; 106-second throttle valve; 107-third throttle valve; 108-fourth throttle valve; 109-fifth throttle valve; 110-first temperature sensor; 201-liquid nitrogen tank; 202-sixth throttle valve; 203-vaporizer; 204-pressure regulating valve; 205-third circulating pump; 206-heat exchanger; 207 -Fourth circulation pump; 208-Seventh throttle valve; 209-Eighth throttle valve; 210-Ninth throttle valve; 211-Tenth throttle valve; 212-Second temperature sensor; 301-Cold storage tank; 302-Eleventh throttle valve; 303-Fifth circulation pump; 304-Twelfth throttle valve; 305-Sixth circulation pump; 306-Thirteenth throttle valve; 307-Fourteenth throttle valve; 308-Fifteenth throttle valve; 401-Water collector; 402-Water distributor. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0040] See also Figures 1 and 2In this embodiment, a liquid nitrogen vaporization cold recovery and utilization system includes a refrigeration unit, a liquid nitrogen unit and a cold storage unit, wherein: the refrigeration unit includes a cooling tower 101, a first circulating pump 102, a refrigeration host 104, and a second circulating pump 105; the liquid nitrogen unit includes a liquid nitrogen tank 201, a vaporizer 203, a third circulating pump 205, a heat exchanger 206, and a fourth circulating pump 207; the cold storage unit includes a cold storage tank 301, a fifth circulating pump 303, and a sixth circulating pump 305.

[0041] The outlet of the cooling tower 101 is connected to the cooling water inlet of the refrigeration main unit 104 through a pipe, the cooling water outlet of the refrigeration main unit 104 is connected to the inlet of the first circulation pump 102 through a pipe, the outlet of the first circulation pump 102 is connected to the inlet of the cooling tower 101 through a pipe, the outlet of the water collector 401 is connected to the inlet of the second circulation pump 105 through a pipe, the outlet of the second circulation pump 105 is connected to the chilled water inlet of the refrigeration main unit 104 through a pipe, and the chilled water outlet of the refrigeration main unit 104 is connected to the inlet of the water distributor 402 through a pipe.

[0042] The outlet of the liquid nitrogen tank 201 is connected to the liquid nitrogen inlet of the vaporizer 203 through a pipeline, the nitrogen outlet of the vaporizer 203 is connected to the inlet of the workshop nitrogen network through a pipeline, the refrigerant outlet of the vaporizer 203 is connected to the inlet of the third circulating pump 205 through a pipeline, the outlet of the third circulating pump 205 is connected to the first inlet of the heat exchanger 206 through a pipeline, the first outlet of the heat exchanger 206 is connected to the refrigerant inlet of the vaporizer 203 through a pipeline, the outlet of the water collector 401 is connected to the inlet 207 of the fourth circulating pump through a pipeline, the outlet of the fourth circulating pump 207 is connected to the second inlet of the heat exchanger 206 through a pipeline, and the second outlet of the heat exchanger 206 is connected to the inlet of the water separator 402 through a pipeline.

[0043] The outlet of the water collector 401 is connected to the inlet of the fifth circulation pump 303 through a pipe, the outlet of the fifth circulation pump 303 is connected to the hot water outlet of the cold storage tank 301 through a pipe, the cold water outlet of the cold storage tank 301 is connected to the inlet of the sixth circulation pump 305 through a pipe, and the outlet of the sixth circulation pump 305 is connected to the inlet of the water distributor 402 through a pipe.

[0044] Preferably, the system further comprises a first throttle valve 103 provided between the inlet of the first circulating pump 102 and the cooling water outlet of the refrigeration main unit 104, the second circulating pump 105 is provided with a first bypass pipe in parallel, the first bypass pipe is provided with a second throttle valve 106, and the chilled water loop of the refrigeration unit is provided with a third throttle valve 107, a fourth throttle valve 108 and a fifth throttle valve 109 in sequence;

[0045] Preferably, the system further includes a sixth throttle valve 202 disposed between the outlet of the liquid nitrogen tank 201 and the liquid nitrogen inlet of the vaporizer 203, a pressure-stabilizing valve 204 is provided between the nitrogen outlet of the vaporizer and the inlet of the workshop nitrogen network, the fourth circulating pump 207 is provided with a second bypass pipe in parallel, the second bypass pipe is provided with a seventh throttle valve 208, and the chilled water loop of the liquid nitrogen unit is provided with an eighth throttle valve 209, a ninth throttle valve 210, and a tenth throttle valve 211 in sequence;

[0046] Preferably, the liquid nitrogen vaporization cold energy recovery and utilization system further includes an eleventh throttle valve 302 provided between the hot water pipe and the cold water pipe of the cold storage tank 301, the fifth circulating pump 303 is provided with a third bypass pipe in parallel, the third bypass pipe is provided with a twelfth throttle valve 304, the sixth circulating pump 305 is provided with a fourth bypass pipe in parallel, the fourth bypass pipe is provided with a thirteenth throttle valve 306, the hot water pipe of the cold storage unit is provided with a fourteenth throttle valve 307, and the cold water pipe of the cold storage unit is provided with a fifteenth throttle valve 308;

[0047] Preferably, the liquid nitrogen vaporization cold energy recovery and utilization system also includes a control module, a first temperature sensor 110 arranged between the chilled water outlet of the refrigeration host 104 and the fourth throttle valve 108, and a second temperature sensor 212 arranged between the second outlet of the heat exchanger 206 and the ninth throttle valve 210.

[0048] The control method of the liquid nitrogen gasification cold energy recovery and utilization system comprises the following steps:

[0049] Step S101: The control module obtains a cooling demand instruction of a chilled water terminal device;

[0050] Step S102: The control module determines whether the liquid nitrogen unit is working. If the liquid nitrogen unit is working, the process proceeds to step S103; if the liquid nitrogen unit is not working, the process proceeds to step S108.

[0051] Step S103: The control module determines whether the liquid nitrogen unit meets the cooling demand based on the chilled water temperature detected by the first temperature sensor 110. If the liquid nitrogen unit meets the cooling demand, the process proceeds to step S104; if the liquid nitrogen unit does not meet the cooling demand, the process proceeds to step S105.

[0052] Step S104: Execute the independent cooling mode of the liquid nitrogen unit. The refrigeration unit and the cold storage unit stop running. The water collector 401, the fourth circulation pump 207, the heat exchanger 206, and the water distributor 402 form a passage so that the liquid nitrogen unit can provide cooling for the terminal.

[0053] Preferably, in step S104, the control module controls the opening of the sixth throttle valve 202 according to the chilled water temperature detected by the second temperature sensor 212. When the temperature detected by the second temperature sensor 212 is greater than the set value, the opening of the sixth throttle valve 202 is increased; when the temperature detected by the second temperature sensor 212 is less than the set value, the opening of the sixth throttle valve 202 is reduced.

[0054] Step S105: The control module determines whether the cold storage unit meets the cooling requirement. If so, the process proceeds to step S106; if not, the process proceeds to step S107.

[0055] Step S106: Execute the liquid nitrogen unit cold storage unit joint cooling mode, the water collector 401, the fourth circulation pump 207, the heat exchanger 206, and the water distributor 402 form a passage, the water collector 401, the cold storage tank 301, the sixth circulation pump 305, and the water distributor 402 form a passage, and the liquid nitrogen unit cold storage unit is combined to provide cooling for the terminal.

[0056] Preferably, in step S106, the control module determines whether the liquid nitrogen unit meets the cooling demand based on the chilled water temperature detected by the second temperature sensor 212. When the temperature detected by the second temperature sensor 212 is greater than the set value, the power of the fourth circulation pump 207 is reduced and the power of the sixth circulation pump 305 is increased. When the temperature detected by the second temperature sensor 212 is less than the set value, the power of the fourth circulation pump 207 is increased and the power of the sixth circulation pump 305 is reduced.

[0057] Step S107: Execute the refrigeration unit cooling and liquid nitrogen unit cold storage mode. The water collector 401, the second circulation pump 105, the refrigeration host 104, and the water distributor 402 form a passage to realize the refrigeration unit to supply cold to the terminal. At the same time, the cold storage tank 301, the fifth circulation pump 303, the heat exchanger 206, and the cold storage tank 301 form a passage to realize the liquid nitrogen unit to supply cold to the cold storage unit.

[0058] Preferably, in step S107, the control module determines whether the refrigeration unit meets the cooling demand based on the chilled water temperature detected by the first temperature sensor 110. When the temperature detected by the first temperature sensor 110 is greater than the set value, the power of the refrigeration host 104 and the second circulating pump 105 is increased; when the temperature detected by the first temperature sensor 110 is less than the set value, the power of the refrigeration host 104 and the second circulating pump 105 is reduced; the control module determines whether the liquid nitrogen unit meets the cold storage demand based on the chilled water temperature detected by the second temperature sensor 212. When the temperature detected by the second temperature sensor 212 is greater than the set value, the power of the fifth circulating pump 303 is reduced; when the temperature detected by the second temperature sensor 212 is less than the set value, the power of the fifth circulating pump 303 is increased.

[0059] Step S108: The control module determines whether the cold storage unit meets the cooling requirement. If so, the process proceeds to step S109; if not, the process proceeds to step S110.

[0060] Step S109: Execute the independent cooling mode of the cold storage unit. The water collector 401, the cold storage tank 301, the sixth circulation pump 305, and the water distributor 402 form a passage to realize the cold storage unit to provide cooling for the terminal.

[0061] Step S110 , executing the independent cooling mode of the refrigeration unit, the water collector 401 , the second circulation pump 105 , the refrigeration host 104 , and the water distributor 402 form a passage, so that the refrigeration unit can provide cooling for the terminal.

[0062] Preferably, in step S110, the control module determines whether the refrigeration unit meets the cooling demand based on the chilled water temperature detected by the first temperature sensor 110. When the temperature detected by the first temperature sensor 110 is greater than the set value, the power of the refrigeration host 104 and the second circulation pump 105 is increased; when the temperature detected by the first temperature sensor 110 is less than the set value, the power of the refrigeration host 104 and the second circulation pump 105 is reduced.

[0063] It should be pointed out in particular that, those skilled in the art will understand that the set temperature value detected by the first temperature sensor and the second temperature sensor can be a specific temperature value or a temperature range, such as 12°C, [7, 12°C], [10°C, 15°C], etc., which can be set specifically according to the terminal cooling demand.

[0064] Please continue reading Figures 3 to 7 ,The following is a detailed description of the operation process of each mode with the help of the attached drawings. Figures 3 to 7 The arrows in the figure indicate the flow direction of the medium.

[0065] like Figure 3 As shown, when the liquid nitrogen unit independent cooling mode is executed, the refrigeration unit and the cold storage unit are not running, the fourth throttle valve 108, the fourteenth throttle valve 307 and the fifteenth throttle valve 308 of the chilled water circuit are closed, the third throttle valve 107, the fifth throttle valve 109, the eighth throttle valve 209, the ninth throttle valve 210 and the tenth throttle valve 211 are opened, the fourth circulation pump 207 is running, and the seventh throttle valve 208 connected in parallel with the fourth circulation pump 207 is closed. Under the action of the fourth circulation pump 207, the circulating chilled water flows through the water collector 401, the fourth circulation pump 207, the heat exchanger 206, and the water distributor 402, so that the liquid nitrogen unit is the terminal cooling;

[0066] like Figure 4As shown, when the liquid nitrogen unit cold storage unit combined cooling mode is executed, the refrigeration unit does not operate, the fourth throttle valve 108 of the chilled water circuit is closed, the third throttle valve 107, the fifth throttle valve 109, the eighth throttle valve 209, the ninth throttle valve 210, the tenth throttle valve 211, the fourteenth throttle valve 307, and the fifteenth throttle valve 308 are opened, the fourth circulation pump 207 is running, the seventh throttle valve 208 connected in parallel with the fourth circulation pump 207 is closed, the eleventh throttle valve 302 of the cold storage unit is closed, the fifth circulation pump 303 is closed, and the seventh throttle valve 208 connected in parallel with the fourth circulation pump 207 is closed. The twelfth throttle valve 304 in parallel with the fifth circulation pump 303 is opened, the sixth circulation pump 305 is running, and the thirteenth throttle valve 306 in parallel with the sixth circulation pump 305 is closed. Under the action of the fourth circulation pump 207, the circulating chilled water flows through the water collector 401, the fourth circulation pump 207, the heat exchanger 206, and the water distributor 402. At the same time, under the action of the sixth circulation pump 305, the circulating chilled water flows through the water collector 401, the cold storage tank 301, the sixth circulation pump 305, and the water distributor 402, so that the liquid nitrogen unit and the cold storage unit are combined to provide cold for the terminal.

[0067] like Figure 5 As shown, when the refrigeration unit supplies cold liquid nitrogen unit in cold storage mode, the eighth throttle valve 209 and the tenth throttle valve 211 of the chilled water circuit are closed, the third throttle valve 107, the fourth throttle valve 108, the fifth throttle valve 109, the ninth throttle valve 210, the fourteenth throttle valve 307 and the fifteenth throttle valve 308 are opened, the second circulation pump 105 is running, the second throttle valve 106 connected in parallel with the second circulation pump 105 is closed, the fourth circulation pump 207 is closed, the seventh throttle valve 208 connected in parallel with the fourth circulation pump 207 is opened, the eleventh throttle valve 302 of the cold storage unit is closed, and the fifth circulation pump 108 is opened. 303 is running, the twelfth throttle valve 304 connected in parallel with the fifth circulation pump 303 is closed, the sixth circulation pump 305 is closed, and the thirteenth throttle valve 306 connected in parallel with the sixth circulation pump 305 is opened. Under the action of the second circulation pump 105, the circulating chilled water flows through the water collector 401, the second circulation pump 105, the refrigeration host 104, and the water distributor 402, so that the refrigeration unit supplies cold to the terminal. At the same time, under the action of the fifth circulation pump 303, the circulating chilled water flows through the cold storage tank 301, the fifth circulation pump 303, the heat exchanger 206, and the cold storage tank 301, so that the liquid nitrogen unit supplies cold to the cold storage unit.

[0068] like Figure 6As shown, when the cold storage unit is in independent cooling mode, the refrigeration unit and the liquid nitrogen unit are not in operation, the fourth throttle valve 108 and the ninth throttle valve 210 of the chilled water circuit are closed, the third throttle valve 107, the fifth throttle valve 109, the eighth throttle valve 209, the tenth throttle valve 211, the fourteenth throttle valve 307 and the fifteenth throttle valve 308 are opened, the fifth circulation pump 303 is closed, the twelfth throttle valve 304 connected in parallel with the fifth circulation pump 303 is opened, the sixth circulation pump 305 is running, and the thirteenth throttle valve 306 connected in parallel with the sixth circulation pump 305 is closed. Under the action of the sixth circulation pump 305, the circulating chilled water flows through the water collector 401, the cold storage tank 301, the sixth circulation pump 305 and the water distributor 402, so that the cold storage unit provides terminal cooling.

[0069] like Figure 7 As shown, when the refrigeration unit is in independent cooling mode, the liquid nitrogen unit and the cold storage unit are not in operation, the eighth throttle valve 209, the ninth throttle valve 210, the tenth throttle valve 211, the fourteenth throttle valve 307 and the fifteenth throttle valve 308 of the chilled water circuit are closed, the third throttle valve 107, the fourth throttle valve 108 and the fifth throttle valve 109 are opened, the second circulating pump 105 is in operation, and the second throttle valve 106 connected in parallel with the second circulating pump 105 is closed. Under the action of the second circulating pump 105, the circulating chilled water flows through the water collector 401, the second circulating pump 105, the refrigeration main unit 104 and the water distributor 402, so that the refrigeration unit provides cooling for the terminal.

[0070] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0071] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent modifications made according to the scope of the claims of the present application are within the scope of protection of the claims of the present application.

Claims

1. A liquid nitrogen gasification cooling energy recovery and utilization system, characterized in that: The invention comprises a water collector (401), a water distributor (402), and a refrigeration unit, a liquid nitrogen unit, and a cold storage unit arranged in parallel between the water collector (401) and the water distributor (402); the cold storage unit comprises a fifth circulating pump (303), a cold storage tank (301), and a sixth circulating pump (305) connected in series, one end of the fifth circulating pump (303) is connected to the water collector (401), and one end of the sixth circulating pump (305) is connected to the water distributor (402); The refrigeration unit comprises a cooling tower (101), a first circulating pump (102), a refrigeration main unit (104) and a second throttle valve (106); the outlet end of the cooling tower (101) is connected to the cooling water inlet end of the refrigeration main unit (104), the cooling water outlet end of the refrigeration main unit (104) is connected to the first circulating pump (102), the other end of the first circulating pump (102) is connected to the inlet end of the cooling tower (101), the water collector (401) is connected to the second circulating pump (105), the other end of the second circulating pump (105) is connected to the chilled water inlet end of the refrigeration main unit (104), and the chilled water outlet of the refrigeration main unit (104) is connected to the water distributor (402); The liquid nitrogen unit comprises a liquid nitrogen tank (201), a sixth throttle valve (202), a vaporizer (203), a third circulating pump (205), a heat exchanger (206) and a fourth circulating pump (207); the outlet of the liquid nitrogen tank (201) is connected to the liquid nitrogen inlet of the vaporizer (203), the nitrogen outlet of the vaporizer (203) is connected to the inlet of the workshop nitrogen network through a pipeline, the coolant outlet of the vaporizer (203) is connected to the inlet of the third circulating pump (205), and the outlet of the third circulating pump (205) is connected to the heat exchanger (206). The first inlet of the heat exchanger (206) is connected, the first outlet of the heat exchanger (206) is connected to the coolant inlet of the vaporizer (203), the outlet of the water collector (401) is connected to the inlet of the fourth circulation pump (207), the outlet of the fourth circulation pump (207) is connected to the second inlet of the heat exchanger (206), and the second outlet of the heat exchanger (206) is connected to the inlet of the water distributor (402); the sixth throttle valve (202) is provided between the outlet of the liquid nitrogen tank (201) and the liquid nitrogen inlet of the vaporizer (203); The system further comprises a control module, a first temperature sensor (110) connected in series between the refrigeration main unit (104) and the water separator (402), and a fourth throttle valve (108) arranged between the first temperature sensor (110) and the water separator (402); and a second temperature sensor (212) arranged between the heat exchanger (206) and the water separator (402), and a ninth throttle valve (210) arranged between the second temperature sensor (212) and the water separator (402).

2. The liquid nitrogen gasification cold energy recovery and utilization system according to claim 1, characterized in that: The cold storage unit further comprises a twelfth throttle valve (304) connected in parallel at both ends of the fifth circulation pump (303), a thirteenth throttle valve (306) connected in parallel at both ends of the sixth circulation pump (305), an eleventh throttle valve (302) connected in parallel at both ends of the cold storage tank (301), a fourteenth throttle valve (307) provided between the water collector (401) and the fifth circulation pump (303), and a fifteenth throttle valve (308) provided between the sixth circulation pump (305) and the water distributor (402).

3. The liquid nitrogen gasification cold energy recovery and utilization system according to claim 1, characterized in that: The liquid nitrogen unit further comprises a seventh throttle valve (208) connected in parallel at both ends of the fourth circulation pump (207), an eighth throttle valve (209) provided between the fourth circulation pump (207) and the water collector (401), and a tenth throttle valve (211) provided between the heat exchanger (206) and the water distributor (402).

4. The liquid nitrogen gasification cold energy recovery and utilization system according to claim 1, characterized in that: The refrigeration unit further includes a second throttle valve (106) connected in parallel at both ends of the second circulation pump (105), a first throttle valve (103) connected in series between the first circulation pump (102) and the refrigeration main unit (104), a third throttle valve (107) provided between the second circulation pump (105) and the water collector (401), and a fifth throttle valve (109) provided between the heat exchanger (206) and the water distributor (402).

5. A control method for the liquid nitrogen gasification cooling energy recovery and utilization system according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step S101: The control module obtains a cooling demand instruction of a chilled water terminal device; Step S102: The control module determines whether the liquid nitrogen unit is working. If the liquid nitrogen unit is working, the process proceeds to step S103; if the liquid nitrogen unit is not working, the process proceeds to step S108. Step S103, the control module determines whether the liquid nitrogen unit meets the cooling demand based on the chilled water supply temperature detected by the second temperature sensor (212), and if the liquid nitrogen unit meets the cooling demand, the control module enters step S104; if the liquid nitrogen unit does not meet the cooling demand, the control module enters step S105; Step S104, executing the liquid nitrogen unit independent cooling mode, the refrigeration unit and the cold storage unit stop running, the water collector (401), the fourth circulation pump (207), the heat exchanger (206), and the water distributor (402) form a passage, and the liquid nitrogen unit is used to supply cooling to the terminal; Step S105: The control module determines whether the cold storage unit meets the cooling requirement. If so, the process proceeds to step S106; if not, the process proceeds to step S107. Step S106, executing the liquid nitrogen unit cold storage unit combined cooling mode, the refrigeration unit stops running, the water collector (401), the fourth circulation pump (207), the heat exchanger (206), and the water distributor (402) form a passage, the water collector (401), the cold storage tank (301), the sixth circulation pump (305), and the water distributor (402) form a passage, and the liquid nitrogen unit cold storage unit is combined to provide cooling for the terminal; Step S107, executing the refrigeration unit cooling liquid nitrogen unit cold storage mode, the water collector (401), the second circulation pump (105), the refrigeration host (104), and the water distributor (402) form a passage, so that the refrigeration unit supplies cold to the terminal, and at the same time the cold storage tank (301), the fifth circulation pump (303), the heat exchanger (206), and the cold storage tank (301) form a passage, so that the liquid nitrogen unit supplies cold to the cold storage unit; Step S108: The control module determines whether the cold storage unit meets the cooling requirement. If so, the process proceeds to step S109; if not, the process proceeds to step S110. Step S109, executing the independent cooling mode of the cold storage unit, the refrigeration unit and the liquid nitrogen unit stop running, the water collector (401), the cold storage tank (301), the sixth circulation pump (305), and the water distributor (402) form a passage, and the cold storage unit provides cooling for the terminal; Step S110, executing the refrigeration unit independent cooling mode, the liquid nitrogen unit and the cold storage unit stop running, the water collector (401), the second circulation pump (105), the refrigeration main unit (104), and the water distributor (402) form a passage, so that the refrigeration unit can provide cooling for the terminal.

6. The control method according to claim 5, characterized in that: In step S104, when the liquid nitrogen unit independent cooling mode is executed, the control module controls the opening of the sixth throttle valve (202) according to the chilled water temperature detected by the second temperature sensor (212). When the temperature detected by the second temperature sensor (212) is greater than the set value, the opening of the sixth throttle valve (202) is increased; when the temperature detected by the second temperature sensor (212) is less than the set value, the opening of the sixth throttle valve (202) is reduced.

7. The control method according to claim 5, characterized in that: In step S106, when the liquid nitrogen unit cold storage unit combined cooling mode is executed, the control module determines whether the liquid nitrogen unit meets the cooling demand based on the chilled water temperature detected by the second temperature sensor (212). When the temperature detected by the second temperature sensor (212) is greater than the set value, the power of the fourth circulation pump (207) is reduced and the power of the sixth circulation pump (305) is increased. When the temperature detected by the second temperature sensor (212) is less than the set value, the power of the fourth circulation pump (207) is increased and the power of the sixth circulation pump (305) is reduced.

8. The control method according to claim 5, characterized in that: In step S107, when the refrigeration unit cools and the liquid nitrogen unit stores cold in the cold storage mode, the control module determines whether the refrigeration unit meets the cold supply demand based on the chilled water temperature detected by the first temperature sensor (110); when the temperature detected by the first temperature sensor (110) is greater than the set value, the power of the refrigeration main unit (104) and the second circulation pump (105) is increased; when the temperature detected by the first temperature sensor (110) is less than the set value, the power of the refrigeration main unit (104) and the second circulation pump (105) is reduced; the control module determines whether the liquid nitrogen unit meets the cold storage demand based on the chilled water temperature detected by the second temperature sensor (212); when the temperature detected by the second temperature sensor (212) is greater than the set value, the power of the fifth circulation pump (303) is reduced; when the temperature detected by the second temperature sensor (212) is less than the set value, the power of the fifth circulation pump (303) is increased.

9. The control method according to claim 5, characterized in that: In step S110, when the refrigeration unit is in an independent cooling mode, the control module determines whether the refrigeration unit meets the cooling demand based on the chilled water temperature detected by the first temperature sensor (110); when the temperature detected by the first temperature sensor (110) is greater than a set value, the power of the refrigeration main unit (104) and the second circulation pump (105) is increased; when the temperature detected by the first temperature sensor (110) is less than the set value, the power of the refrigeration main unit (104) and the second circulation pump (105) is reduced.

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