An LNG vehicle and ship refrigeration micro-power air conditioning system

Abstract

The present invention relates to the field of LNG air conditioners, and specifically provides an LNG vehicle and ship refrigeration micro-power air conditioning system, which includes an LNG storage tank for storing LNG, and a coolant cooling unit is provided inside the LNG storage tank; a main medium heat exchange unit and a coolant heating unit are provided inside the water bath heat exchanger; the three-medium heat exchanger includes a housing, a cold storage heat exchanger and a lower heat exchanger. The housing is connected to the LNG storage tank coolant outlet pipeline, the three-medium heat exchanger coolant outlet pipeline and the coolant circulation pump. There is a cavity inside the housing, and the coolant is inside the cavity. The cold storage heat exchanger and the lower heat exchanger are located inside the cavity; the air conditioning refrigeration unit includes a fan coil heat exchange unit and a secondary coolant circulation pump, and the fan coil heat exchange unit is connected to the lower heat exchanger and the secondary coolant circulation pump; the control unit is connected to the coolant circulation pump, the secondary coolant circulation pump and the fan in a controlled manner. The present invention adopts a three-medium heat exchange solution driven by micro-power to solve the problem that the refrigeration cannot be carried out when the power unit stops, and realizes the function of a parking air conditioner.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG air conditioners, and particularly to an LNG vehicle and ship refrigeration micro-power air conditioning system. Background Art

[0002] With the in-depth transformation of China's energy consumption structure, as a clean energy, LNG has developed rapidly and been widely used in various fields due to its advantages such as high calorific value, low price, low pollution after combustion, and environmental friendliness. As a fuel, LNG is safe, efficient, clean and pollution-free, which not only promotes the transformation of China's energy structure, but also effectively reduces the environmental pollution caused by the emission of combustion waste gas.

[0003] A large amount of cold energy is released during the vaporization process of LNG before combustion. Usually, this part of cold energy is directly discharged into the atmospheric environment, resulting in waste of cold energy. Traditional air-conditioning refrigeration systems generally use compressors as the core equipment of the refrigeration system. However, compressors require a certain economic cost and generate noise during operation. Some LNG-based air-conditioning refrigeration systems have also been proposed in the prior art. These refrigeration systems generally adopt a double-medium heat exchange scheme in which a secondary coolant directly exchanges heat with LNG. Due to the excessive heat exchange temperature difference between LNG and the secondary coolant, the refrigeration system is prone to problems such as freezing of the secondary coolant and poor heat exchange, and cannot ensure the safe and stable operation of the refrigeration system. In the prior art, the cold energy storage and utilization of LNG need to be carried out under the working state of the power unit, and the function of providing air conditioning - that is, "parking air conditioning" - cannot be realized after the power unit stops. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: In order to solve the problems of freezing of the secondary coolant and poor heat exchange in the LNG vehicle and ship refrigeration air-conditioning system in the prior art, and the inability to realize the function of parking air conditioning, the present invention provides an LNG vehicle and ship refrigeration micro-power air conditioning system to solve the above problems.

[0005] The technical solution adopted by the present invention to solve its technical problems is: An LNG vehicle and ship refrigeration micro-power air conditioning system, including an LNG storage tank, the LNG storage tank is used for storing LNG and is connected to a main medium first pipeline, a manual first stop valve is arranged at one end of the main medium pipeline close to the LNG storage tank, a pressure sensor is also arranged on the LNG storage tank, and a secondary coolant cooling unit is arranged in the LNG storage tank. The inlet end of the secondary coolant cooling unit is connected to the LNG storage tank secondary coolant inlet pipeline, and the outlet end of the secondary coolant cooling unit is connected to the LNG storage tank secondary coolant outlet pipeline;

[0006] Water bath heat exchanger, which has a main medium heat exchange unit and a cold storage agent heating unit inside. The inlet end of the main medium heat exchange unit is connected to the LNG storage tank through the first main medium pipeline, the outlet end of the main medium heat exchange unit is connected to the second main medium pipeline, the inlet end of the cold storage agent heating unit is connected to the first cold storage agent heat exchange pipeline, the outlet end of the cold storage agent heating unit is connected to the second cold storage agent heat exchange pipeline, and the water bath heat exchanger is also connected with a hot water unit;

[0007] Three-medium heat exchanger, which includes a shell, a cold storage heat exchanger and a lower heat exchanger. The inlet end of the shell is connected to the cold storage agent outlet pipeline of the LNG storage tank, the outlet end of the shell is connected to the cold storage agent outlet pipeline of the three-medium heat exchanger. The cold storage agent outlet pipeline of the three-medium heat exchanger is connected to the cold storage agent inlet pipeline of the LNG storage tank and the first cold storage agent heat exchange pipeline through a second electromagnetic three-way valve. A cold storage agent circulation pump is also installed on the cold storage agent outlet pipeline of the three-medium heat exchanger. There is a cavity inside the shell, and a cold storage agent with gas-liquid conversion characteristics is filled in the cavity. The cold storage agent includes a gaseous phase cold storage agent in a gaseous state and a liquid phase cold storage agent in a liquid state, and the gaseous and liquid states of the cold storage agent can be converted into each other. The inlet end of the cold storage heat exchanger is connected to the LNG storage tank, the outlet end of the cold storage heat exchanger is connected to the outlet pipeline of the cold storage pipeline, the cold storage agent outlet pipeline is connected to the second main medium pipeline, the cold storage heat exchanger is located in the cavity and is in full contact with the gaseous phase cold storage agent, and the lower heat exchanger is located in the cavity and is in full contact with the liquid phase cold storage agent;

[0008] Air conditioning refrigeration unit, which includes a fan coil heat exchange unit and a secondary refrigerant circulation pump. The inlet end of the fan coil heat exchange unit is connected to the outlet end of the lower heat exchanger through the coil inlet pipe, the outlet end of the fan coil heat exchange unit is connected to the inlet end of the secondary refrigerant circulation pump, the outlet end of the secondary refrigerant circulation pump is connected to the inlet end of the lower heat exchanger, and a secondary refrigerant is provided in the loop formed by connecting the lower heat exchanger, the fan coil heat exchange unit and the secondary refrigerant circulation pump;

[0009] Control unit, which is connected to the second electromagnetic three-way valve, the cold storage agent circulation pump, the secondary refrigerant circulation pump and the fan in a controlled manner.

[0010] Preferably, it further includes a power unit, which is connected to the third main medium pipeline. The third main medium pipeline is connected to the outlet pipeline of the cold storage pipeline and the second main medium pipeline through a first electromagnetic three-way valve, and the first electromagnetic three-way valve is connected to the control unit in a controlled manner;

[0011] The inlet end of the cold storage heat exchanger is connected to the first main medium pipeline through the inlet pipe of the cold storage pipeline, and the connection between the inlet pipe of the cold storage pipeline and the main medium pipeline is located between the manual first stop valve and the water bath heat exchanger;

[0012] The outlet end of the cold storage heat exchanger is connected to the third main medium pipeline through the outlet pipe of the cold storage pipeline and the first electromagnetic three-way valve, and the connection between the outlet pipe of the cold storage pipeline and the third main medium pipeline is located between the second main medium pipeline and the third main medium pipeline;

[0013] The cold storage agent outlet pipeline of the three-medium heat exchanger is connected to the cold storage agent circulation pump through the manual second stop valve, and the cold storage agent circulation pump is connected to the LNG storage tank cold storage agent inlet pipeline through the second electromagnetic three-way valve; the cold storage agent cooling unit is placed in the LNG storage tank, connected to the second electromagnetic three-way valve through the LNG storage tank cold storage agent inlet pipeline, and connected to the three-medium heat exchanger through the LNG storage tank cold storage agent outlet pipeline, forming a micro-power cycle cold storage system.

[0014] Preferably, the water bath heat exchanger includes a cold storage agent heating unit, which is connected to the second electromagnetic three-way valve through the first cold storage agent heat exchange pipeline and connected to the LNG storage tank cold storage agent inlet pipeline through the second cold storage agent heat exchange pipeline;

[0015] The cold storage agent outlet pipeline of the three-medium heat exchanger is connected to the cold storage agent circulation pump through the manual second stop valve, and the cold storage agent circulation pump is connected to the first cold storage agent heat exchange pipeline and the cold storage agent heating unit through the second electromagnetic three-way valve; the cold storage agent heating unit is connected to the cold storage agent cooling unit placed in the LNG storage tank through the second cold storage agent heat exchange pipeline and the LNG storage tank cold storage agent inlet pipeline; the LNG storage tank cold storage agent outlet pipeline is connected to the cold storage agent cooling unit and the three-medium heat exchanger, forming a circulating pressurization and saturation adjustment system for the LNG storage tank.

[0016] Preferably, the fan coil heat exchange unit includes a fan, a coil heat exchanger and heat exchange fins. The heat exchange fins are arranged on the coil heat exchanger. The fan is located on one side of the coil heat exchanger, and an air outlet is arranged on the other side of the coil heat exchanger. The blowing direction of the fan faces the coil heat exchanger. The inlet end of the coil heat exchanger is connected to the outlet end of the lower heat exchanger through the coil inlet pipe, and the outlet end of the coil heat exchanger is connected to the secondary coolant circulation pump. A secondary coolant buffer tank is also arranged between the secondary coolant circulation pump and the coil heat exchanger. The inlet end of the secondary coolant buffer tank is connected to the outlet end of the coil heat exchanger through the coil outlet pipe, and the outlet end of the secondary coolant buffer tank is connected to the inlet end of the secondary coolant circulation pump through the secondary coolant pipeline.

[0017] A manual third stop valve is installed on the pipeline between the inlet end of the secondary refrigerant circulation pump and the outlet end of the secondary refrigerant buffer tank, and a manual fourth stop valve is installed on the pipeline between the outlet end of the secondary refrigerant circulation pump and the inlet end of the lower heat exchanger.

[0018] A manual second stop valve is also installed on the secondary refrigerant outlet pipeline of the three-medium heat exchanger between the secondary refrigerant circulation pump and the housing.

[0019] Preferably, a first temperature sensor and a safety valve are provided on the three-medium heat exchanger. The first temperature sensor is used to monitor the temperature of the liquid-phase secondary refrigerant, and the safety valve is used to automatically lift and relieve pressure when the pressure of the gas-phase secondary refrigerant exceeds the standard. A third temperature sensor is provided at the inlet end of the coil heat exchanger, a second temperature sensor is provided at the outlet end of the coil heat exchanger, a fourth temperature sensor is provided near the air outlet, and the control unit is in communication with the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor.

[0020] The beneficial effects of the present invention are as follows:

[0021] First, the cold energy of LNG is recovered as the cold source of the air-conditioning refrigeration system, avoiding the waste of a large amount of cold energy caused by the vaporization of LNG, eliminating the high-power-consuming component - the compressor that is necessary for the conventional vapor compression refrigeration cycle, reducing the fuel consumption and waste gas emissions of the power unit, and having remarkable energy-saving and emission-reduction effects.

[0022] Second, when the power unit stops working, it is driven by a micro-power power supply. The three-medium heat exchanger is used to store cold energy by the micro-power circulation of the secondary refrigerant to recover the cold energy of LNG, overcoming the high-temperature difference heat transfer barrier that cannot be broken through in the heat transfer between LNG and the secondary refrigerant, eliminating the problems of freezing and poor heat transfer of the secondary refrigerant during the heat transfer between the two media, and driving the secondary refrigerant circulation pump and the fan for air-conditioning refrigeration, realizing the function of providing air-conditioning - that is, "parking air-conditioning" after the power unit stops, ensuring the stable and safe operation of the LNG vehicle and ship refrigeration micro-power air-conditioning system, with high system efficiency and simple process.

[0023] Third, the three-medium heat exchanger is used to realize the controllable pressurization and saturation adjustment of the LNG storage tank through the pressurization and saturation adjustment cycle of the secondary refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the drawings and embodiments.

[0025] Figure 1 It is a schematic structural diagram of the optimal embodiment of an LNG vehicle and ship refrigeration micro-power air-conditioning system of the present invention;

[0026] Figure 2It is a schematic diagram of the pressurization and saturation adjustment process of the LNG storage tank of an LNG vehicle and ship refrigeration micro-power air conditioning system according to the present invention;

[0027] Figure 3 It is a schematic diagram of the micro-power cycle cold storage process of an LNG vehicle and ship refrigeration micro-power air conditioning system according to the present invention;

[0028] Figure 4 It is a schematic diagram of the refrigeration process of an LNG vehicle and ship refrigeration micro-power air conditioning system according to the present invention.

[0029] In the figure, 101 is the LNG storage tank, 102 is the pressure sensor, 103 is the manual first stop valve, 104 is the main medium first pipeline, 105 is the water bath heat exchanger, 106 is the main medium heat exchange unit, 107 is the hot water unit, 108 is the main medium second pipeline, 109 is the first electromagnetic three-way valve, 110 is the main medium third pipeline, 111 is the power unit, 201 is the three-medium heat exchanger, 202 is the gaseous coolant, 203 is the liquid coolant, 204 is the housing, 205 is the first temperature sensor, 206 is the safety valve, 207 is the three-medium heat exchanger coolant outlet pipeline, 208 is the manual second stop valve, 209 is the coolant circulation pump, 210 is the second electromagnetic three-way valve, 211 is the coolant first heat exchange pipeline, 212 is the coolant heating unit, 213 is the coolant second heat exchange pipeline, 214 is the LNG storage tank coolant inlet pipeline, 215 is the coolant cooling unit, 216 is the LNG storage tank coolant outlet pipeline, 301 is the cooling space, 302 is the lower heat exchanger, 303 is the coil inlet pipe, 304 is the fan coil heat exchange unit, 305 is the coil outlet pipe, 306 is the coolant buffer tank, 307 is the coolant pipeline, 308 is the manual third stop valve, 309 is the coolant circulation pump, 310 is the manual fourth stop valve, 311 is the second temperature sensor, 312 is the third temperature sensor, 313 is the fourth temperature sensor, 314 is the fan, 315 is the coil heat exchanger, 316 is the heat exchange fin, 317 is the coolant, 401 is the cold storage pipeline inlet pipe, 402 is the cold storage heat exchanger, 403 is the cold storage pipeline outlet pipe, 501 is the control unit. Detailed implementation manners

[0030] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0031] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0032] In addition, terms such as "first", "second", etc. are only used for descriptive purposes and should not be construed as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0033] As Figure 1 shown, the present invention provides an embodiment of an LNG vehicle and ship refrigeration micro-power air conditioning system, including an LNG storage tank 101 for storing LNG and communicating with a main medium first pipeline 104. A manual first stop valve 103 is provided at one end of the main medium pipeline close to the LNG storage tank 101. A pressure sensor 102 is also provided on the LNG storage tank 101 for monitoring the pressure of the LNG storage tank 101. An ice storage agent cooling unit 215 is provided in the LNG storage tank 101. The inlet end of the ice storage agent cooling unit 215 is communicated with an LNG storage tank ice storage agent inlet pipeline 214, and the outlet end of the ice storage agent cooling unit 215 is communicated with an LNG storage tank ice storage agent outlet pipeline 216;

[0034] Water bath heat exchanger 105, the water bath heat exchanger 105 has a main medium heat exchange unit 106 and a cold storage agent heating unit 212 inside. The inlet end of the main medium heat exchange unit 106 is connected to the LNG storage tank 101 through the main medium first pipeline 104. The outlet end of the main medium heat exchange unit 106 is connected to the main medium second pipeline 108. The inlet end of the cold storage agent heating unit 212 is connected to the cold storage agent first heat exchange pipeline 211. The outlet end of the cold storage agent heating unit 212 is connected to the cold storage agent second heat exchange pipeline 213. The water bath heat exchanger 105 is also connected with a hot water unit 107. The water bath heat exchanger 105 exchanges heat with the hot water unit 107 through the main medium heat exchange unit 106 to heat the LNG to natural gas at a set temperature, and exchanges heat with the hot water unit 107 through the cold storage agent heating unit 212 to heat the cold storage agent to a set temperature.

[0035] Three-medium heat exchanger 201, the three-medium heat exchanger 201 includes a housing 204, a cold storage heat exchanger 402 and a lower heat exchanger 302. The inlet end of the housing 204 is connected to the LNG storage tank cold storage agent outlet pipeline 216. The outlet end of the housing 204 is connected to the three-medium heat exchanger cold storage agent outlet pipeline 207. The three-medium heat exchanger cold storage agent outlet pipeline 207 is connected to the LNG storage tank cold storage agent inlet pipeline 214 and the cold storage agent first heat exchange pipeline 211 through a second electromagnetic three-way valve 210. A cold storage agent circulation pump 209 is also installed on the three-medium heat exchanger cold storage agent outlet pipeline 207. A manual second stop valve is also installed on the three-medium heat exchanger cold storage agent outlet pipeline 207 between the cold storage agent circulation pump 209 and the housing 204, that is, the second electromagnetic three-way valve 210 and the manual second stop valve are installed on the pipelines at both ends of the cold storage agent circulation pump 209;

[0036] The housing 204 has a cavity inside, and a cold storage agent with gas-liquid conversion characteristics is contained in the cavity. The cold storage agent includes a gaseous phase cold storage agent 202 in a gaseous state and a liquid phase cold storage agent 203 in a liquid state. The gaseous and liquid states of the cold storage agent can be converted into each other, and its solidification temperature is lower than the temperature of the LNG in the LNG storage tank 101, that is, it will not freeze due to absorbing the cold of the LNG under any circumstances. The cold storage agent has a relatively high liquefaction temperature and a relatively low liquefaction pressure. That is, when the temperature is high, for example, when the temperature is 50 °C and remains in a liquid state, the pressure in the cavity will not be too high. The cold storage agent has a relatively high thermal conductivity in both gaseous and liquid states and has a relatively large latent heat of vaporization. In the cavity, the gaseous phase cold storage agent 202 is located above the liquid phase cold storage agent 203, and the temperature of the gaseous phase cold storage agent 202 is higher than the temperature of the liquid phase cold storage agent 203. The gaseous phase cold storage agent 202 can be liquefied into the liquid phase cold storage agent 203 by absorbing the cold of the LNG, and the liquid phase cold storage agent 203 can be vaporized into the gaseous phase cold storage agent 202 by absorbing heat.

[0037] The inlet end of the cold storage heat exchanger 402 is connected to the first main medium pipeline 104 through the cold storage pipeline inlet pipe 401, that is, after the manual first stop valve 103 is opened, LNG enters the first main medium pipeline 104 from the LNG storage tank 101, and enters the cold storage heat exchanger from the cold storage pipeline inlet pipe 401. The connection between the cold storage pipeline inlet pipe 401 and the first main medium pipeline 104 is located between the manual first stop valve 103 and the water bath heat exchanger 1 05, the outlet end of the cold storage heat exchanger 402 is connected to the cold storage pipeline outlet pipe 403, the cold storage agent outlet pipeline is connected to the second main medium pipeline 108, the cold storage heat exchanger 402 is located in the cavity and is in full contact with the gas phase cold storage agent 202, LNG is present in the cold storage agent heat exchanger, the lower heat exchanger 302 is located in the cavity and is in full contact with the liquid phase cold storage agent 203, and the lower heat exchanger 302 is in the coolant 317;

[0038] The three-medium heat exchanger 201 is also provided with a first temperature sensor 205 and a safety valve 206. The first temperature sensor 205 is used to measure the temperature of the liquid-phase refrigerant 203. The safety valve 206 is arranged at the upper end of the three-medium heat exchanger 201 and has a pre-set trip threshold. When the pressure of the gas-phase refrigerant 202 exceeds the trip threshold, the safety valve 206 automatically trips and releases pressure, thereby achieving automatic tripping and pressure relief when the pressure of the gas-phase refrigerant 202 exceeds the standard, thereby ensuring the safe operation of the three-medium heat exchanger 201.

[0039] An air conditioning refrigeration unit, the air conditioning refrigeration unit comprising a fan coil heat exchange unit 304 and a refrigerant circulation pump 309, the inlet end of the fan coil heat exchange unit 304 is connected to the outlet end of the lower heat exchanger 302 through the coil inlet pipe 303, the outlet end of the fan coil heat exchange unit 304 is connected to the inlet end of the refrigerant circulation pump 309, the outlet end of the refrigerant circulation pump 309 is connected to the inlet end of the lower heat exchanger 302, and the lower heat exchanger 302, the fan coil heat exchange unit 304 and the refrigerant circulation pump 309 are connected to form a loop with refrigerant 317;

[0040] The fan coil heat exchange unit 304 includes a fan 314, a coil heat exchanger 315, and heat exchange fins 316. The heat exchange fins 316 are arranged on the coil heat exchanger 315. The fan 314 is located on one side of the coil heat exchanger 315. An air outlet is arranged on the other side of the coil heat exchanger 315. A fourth temperature sensor 313 is arranged near the air outlet. The fourth temperature sensor 313 is located in the cooling space 301 and is used to measure the temperature of the cooling space 301. The blowing direction of the fan 314 faces the coil heat exchanger 315. The inlet end of the coil heat exchanger 315 is communicated with the outlet end of the lower heat exchanger 302 through the coil inlet pipe 303. The outlet end of the coil heat exchanger 315 is communicated with the coolant circulation pump 309. A coolant buffer tank 306 is also arranged between the coolant circulation pump 309 and the coil heat exchanger 315. The inlet end of the coolant buffer tank 306 is communicated with the outlet end of the coil heat exchanger 315 through the coil outlet pipe 305. The outlet end of the coolant buffer tank 306 is communicated with the inlet end of the coolant circulation pump 309 through a coolant pipeline 307. The coolant buffer tank 306 is used to temporarily store the coolant 317 in the air-conditioning refrigeration unit and compensate for the volume fluctuation of the coolant 317 caused by its own temperature change, ensuring the stable operation of the air-conditioning refrigeration unit.

[0041] The third temperature sensor 312 is located between the outlet end of the lower heat exchanger 302 and the inlet end of the coil heat exchanger 315. The second temperature sensor 311 is located between the outlet end of the coil heat exchanger 315 and the coolant buffer tank 306. The third temperature sensor 312 is used to measure the temperature of the coolant 317 entering the coil heat exchanger 315. The second temperature sensor 311 is used to measure the temperature of the coolant 317 flowing out of the coil heat exchanger 315.

[0042] A control unit 501, the control unit 501 is a device with data receiving and processing capabilities. The control unit 501 is controllably connected to the second electromagnetic three-way valve 210, the cool storage agent circulation pump 209, the coolant circulation pump 309, and the fan 314. The control unit 501 is communicatively connected to the first temperature sensor 205, the second temperature sensor 311, the third temperature sensor 312, and the fourth temperature sensor 313.

[0043] As Figure 4As shown, when the air-conditioning refrigeration unit is operating, the control unit 501 controls the blower 314 and the secondary refrigerant circulation pump 309 to start. Under the action of the secondary refrigerant circulation pump 309, the secondary refrigerant 317 circulates within the air-conditioning refrigeration unit. The secondary refrigerant 317 absorbs the cold energy of the liquid-phase cold storage agent 203 in the lower heat exchanger 302, and the temperature of the secondary refrigerant 317 decreases. Then it flows into the coil heat exchanger 315. The blower 314 forces the air in the cooling space 301 to flow through the coil heat exchanger 315 and the heat exchange fins 316 for heat exchange. The air absorbs the cold energy of the secondary refrigerant 317 and its temperature decreases, and then is blown out from the air outlet to cool the cooling space 301. When the control unit 501 monitors that the air temperature in the cooling space 301 reaches the set temperature, the control unit 501 finely controls the flow rate of the secondary refrigerant 317 by adjusting the rotational speed of the secondary refrigerant circulation pump 309, and precisely controls the temperature in the cooling space 301 by analyzing the temperature data of the secondary refrigerant 317 before and after refrigeration monitored by the third temperature sensor 312 and the second temperature sensor 311. At the same time, the user can adjust the rotational speed of the blower 314 through the control unit 501 to adjust the cooling rate of the cooling space 301. Since a large amount of cold energy is stored in the cold storage agent in the three-medium heat exchanger 201, the secondary refrigerant 317 can obtain cold energy from the liquid-phase cold storage agent 203 through the lower heat exchanger 302. Therefore, when the power unit 111 stops operating, the air-conditioning refrigeration unit can still perform the refrigeration operation, functioning as a micro-power cycle refrigeration, and realizing the function of a "parking air conditioner". During the refrigeration process of the LNG vehicle and ship refrigeration micro-power air-conditioning system, as the air-conditioning refrigeration system continues to operate, the temperature of the liquid-phase cold storage agent 203 gradually increases and is continuously vaporized into the gas-phase cold storage agent 202. When the first temperature sensor 205 monitors that the temperature of the liquid-phase cold storage agent 203 reaches the maximum temperature of the secondary refrigerant 317 required for the operation of the fan coil heat exchange unit 304, the control unit 501 shuts down the secondary refrigerant circulation pump 309, and the refrigeration process of the cold storage air conditioner ends. The control unit 501 can control the start, stop, and rotational speed adjustment of the blower 314 and the secondary refrigerant circulation pump 309. Conventional air-conditioning refrigeration systems generally use a compressor as the core equipment of the refrigeration system. The compressor is a power device that consumes a large amount of electrical energy during operation and has relatively large vibration and noise. Additional costs are required for the purchase and maintenance of the compressor, resulting in a relatively high usage cost. The LNG vehicle and ship refrigeration micro-power air-conditioning system provided by the present invention uses the three-medium heat exchanger 201 to recover the cold energy of LNG as the cold source of the air-conditioning refrigeration system, eliminating the high-power-consuming component compressor that is necessary for the conventional vapor compression refrigeration cycle. The three-medium heat exchanger 201 operates without consuming any electrical energy, and has high economic and environmental benefits compared with traditional refrigeration systems.

[0044] When the power unit 111 and the air-conditioning refrigeration unit are operating simultaneously, as Figure 1As shown, the liquid-phase coolant 203 absorbs the heat of the secondary coolant 317 and its temperature rises. The coolant passes through the coolant outlet pipeline 207 of the three-medium heat exchanger and the manual second stop valve, and after being pressurized by the coolant circulation pump 209, it enters the coolant cooling unit 215 through the second electromagnetic three-way valve 210 and the LNG storage tank coolant inlet pipeline 214, exchanges heat with the LNG in the LNG storage tank 101, and then returns to the three-medium heat exchanger 201 through the LNG storage tank coolant outlet pipeline 216. When the cooling rate of the coolant in the coolant cooling unit 215 is greater than the heating rate of the liquid-phase coolant 203, the temperature of the liquid-phase coolant 203 will drop to the freezing temperature of the secondary coolant 317. At this time, the control unit 501 controls to reduce the rotation speed of the coolant circulation pump 209 and reduce the coolant flow rate entering the coolant cooling unit 215. When the heating rate of the coolant in the coolant cooling unit 215 is less than the heating rate of the liquid-phase coolant 203, the temperature of the liquid-phase coolant 203 will continue to rise. At this time, the control unit 501 controls to increase the rotation speed of the coolant circulation pump 209, increase the coolant flow rate entering the coolant cooling unit 215, and increase the cold input.

[0045] As Figure 2 shown, it further includes a power unit 111. The power unit 111 is connected to the main medium third pipeline 110. The main medium third pipeline 110 is connected to the coolant pipeline outlet 403 and the main medium second pipeline 108 through the first electromagnetic three-way valve 109. The first electromagnetic three-way valve 109 is controlled and connected to the control unit 501. The power unit 111 is a heat energy application device fueled by natural gas. Since the LNG parking air-conditioning refrigeration system generally only operates in hot weather, when it is in winter or the air conditioner does not need to run for a long time and only the power unit 111 needs to operate, first open the manual first stop valve 103. At this time, the first electromagnetic three-way valve 109 is in the normally open position, connecting the main medium second pipeline 108 and the main medium third pipeline 110. The LNG stops entering the coolant heat exchanger. The gas is vaporized by the water bath heat exchanger 105 from the main medium first pipeline 104 and then enters the power unit 111 through the main medium second pipeline 108, the first electromagnetic three-way valve 109 and the main medium third pipeline 110 to do work by combustion.

[0046] During the operation of the power unit 111, the gas phase space pressure of the LNG storage tank 101 will decrease due to the decrease of the LNG liquid level, and a pressurization and saturation adjustment operation is required. The cold storage agent circulation pump 209 is a variable-frequency cold storage agent circulation pump 209. The control unit 501 monitors according to the pressure value of the pressure sensor 102, controls the opening, closing and speed adjustment of the cold storage agent circulation pump 209, realizes the controllable pressurization and saturation adjustment of the LNG storage tank 101. The cold storage agent passes through the cold storage agent outlet pipeline 207 of the three-medium heat exchanger and the manual second stop valve 208, is pressurized by the cold storage agent circulation pump 209, and then passes through the second electromagnetic three-way valve 210 and the cold storage agent first heat exchange pipeline 211 to exchange heat with the hot water unit 107 in the cold storage agent heating unit 212. After heating, it enters the cold storage agent cooling unit 215 through the cold storage agent second heat exchange pipeline 213 and the LNG storage tank cold storage agent inlet pipeline 214, exchanges heat with the LNG in the LNG storage tank 101, and after cooling, returns to the three-medium heat exchanger 201 through the LNG storage tank cold storage agent outlet pipeline 216. During the circulation process, the heat of the hot water unit 107 is transferred into the LNG storage tank 101 to realize the gasification and pressurization of LNG and complete the pressurization and saturation adjustment cycle of the LNG storage tank 101.

[0047] As Figure 3 shown, when the power unit 111 stops being used, the control unit 501 controls the first electromagnetic three-way valve 109 to cut off the connection between the main medium third pipeline 110 and the cold storage pipeline outlet pipe 403, and the LNG stops entering the cold storage agent heat exchanger. During the micro-power cycle cold storage process of the LNG vehicle and ship refrigeration micro-power air-conditioning system, the control unit 501 controls the second electromagnetic three-way valve 210 to connect the cold storage agent outlet pipeline 207 of the three-medium heat exchanger and the LNG storage tank cold storage agent inlet pipeline 214. The cold storage agent passes through the cold storage agent outlet pipeline 207 of the three-medium heat exchanger and the manual second stop valve, is pressurized by the cold storage agent circulation pump 209, and then enters the cold storage agent cooling unit 215 in the LNG storage tank 101 through the second electromagnetic three-way valve 210 and the LNG storage tank cold storage agent inlet pipeline 214 for heat exchange and cooling. After cooling, it returns to the three-medium heat exchanger 201 through the LNG storage tank cold storage agent outlet pipeline 216 to realize the micro-power cycle cold storage. During the micro-power cycle cold storage process, the cold storage agent absorbs the cold energy of the LNG in the LNG storage tank 101, the LNG absorbs heat and gasifies, and the tank pressure rises. After the pressure sensor 102 monitors that the pressure of the LNG storage tank 101 reaches the set value, the control unit 501 controls the cold storage agent circulation pump 209 to stop, and the micro-power cold storage cycle stops.

[0048] In the three-medium heat exchanger 201, the gaseous cold storage agent 202 absorbs the cold energy of LNG and is continuously liquefied. The pressure in the cavity gradually decreases. When the pressure is lower than the evaporation pressure of the liquid-phase cold storage agent 203, the evaporation of the liquid-phase cold storage agent 203 accelerates. In this way, the indirect transfer and storage of cold energy are realized. When the temperature first sensor 205 monitors that the temperature of the liquid-phase cold storage agent 203 is close to the freezing temperature of the secondary coolant 317, the control unit 501 adjusts the first electromagnetic three-way valve 109 on the outlet pipe 403 of the cold storage pipeline to prevent LNG from entering the cold storage agent heat exchanger, so as to control the cold energy input of the three-medium heat exchanger 201. Since the mass and specific heat capacity of the liquid-phase cold storage agent 203 in the three-medium heat exchanger 201 are relatively large, it effectively avoids the problem that the temperature of the liquid-phase cold storage agent 203 is too low caused by the low control accuracy of the LNG flow rate and the continuous cooling of the LNG remaining in the cold storage agent heat exchanger and the outlet pipe 403 of the cold storage pipeline after the first electromagnetic three-way valve 109 is switched. Furthermore, it eliminates the freezing problem of the secondary coolant 317 and overcomes the high-temperature difference heat transfer obstacle that cannot be broken through by the double-medium heat exchange between LNG and the secondary coolant 317.

[0049] In other embodiments, all the manually operated stop valves provided are maintenance operation valves and are not used as normal process operation valves. When it is necessary to replace or repair the LNG storage tank 101, the operator needs to first close the manually operated first stop valve 103, and then perform the replacement and repair operations on the LNG storage tank 101.

[0050] A manually operated second stop valve 208 is also installed at the outlet of the cold storage agent outlet pipeline 270 of the three-medium heat exchanger at the inlet end of the cold storage agent circulation pump 209. A second electromagnetic three-way valve 210 is installed at the inlet of the first cold storage agent heat exchange pipeline 211 at the outlet end of the cold storage agent circulation pump 209. That is, the manually operated second stop valve 208 and the second electromagnetic three-way valve 210 are respectively installed on the pipelines at the inlet end and the outlet end of the cold storage agent circulation pump 209. When it is necessary to replace or repair the cold storage agent circulation pump 209, the operator can first close the manually operated second stop valve and the second electromagnetic three-way valve, and then remove the cold storage agent circulation pump 209 to avoid the leakage of the cold storage agent in the three-medium heat exchanger.

[0051] A manually operated third stop valve 308 is also installed on the pipeline between the inlet end of the secondary coolant circulation pump 309 and the outlet end of the secondary coolant buffer tank 306. A manually operated fourth stop valve 310 is installed on the pipeline between the outlet end of the secondary coolant circulation pump 309 and the inlet end of the lower heat exchanger 302. That is, the manually operated third stop valve 308 and the manually operated fourth stop valve 310 are respectively installed on the pipelines at the inlet end and the outlet end of the secondary coolant circulation pump 309. When it is necessary to replace or repair the secondary coolant circulation pump 309, the operator can first close the manually operated third stop valve and the manually operated fourth stop valve, and then remove the secondary coolant circulation pump 309 to avoid the leakage of the secondary coolant 317 in the air-conditioning refrigeration unit.

[0052] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0053] Based on the above inspiration from the ideal embodiments of the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A refrigeration micro-power air conditioning system for LNG vehicles and ships, characterized in that, Comprising: An LNG storage tank for storing LNG and communicating with a first main medium pipeline. A manual first stop valve is provided at one end of the first main medium pipeline close to the LNG storage tank. A pressure sensor is also provided on the LNG storage tank. An endothermic agent cooling unit is provided inside the LNG storage tank. The inlet end of the endothermic agent cooling unit communicates with the LNG storage tank endothermic agent inlet pipeline, and the outlet end of the endothermic agent cooling unit communicates with the LNG storage tank endothermic agent outlet pipeline; A water-bath heat exchanger having a main medium heat exchange unit and an endothermic agent heating unit inside. The inlet end of the main medium heat exchange unit communicates with the LNG storage tank through the first main medium pipeline. The outlet end of the main medium heat exchange unit communicates with the second main medium pipeline. The inlet end of the endothermic agent heating unit communicates with the first endothermic agent heat exchange pipeline, and the outlet end of the endothermic agent heating unit communicates with the second endothermic agent heat exchange pipeline. The water-bath heat exchanger is also connected to a hot water unit; A three-medium heat exchanger including a shell, a cold storage heat exchanger and a lower heat exchanger. The inlet end of the shell communicates with the LNG storage tank endothermic agent outlet pipeline, and the outlet end of the shell communicates with the three-medium heat exchanger endothermic agent outlet pipeline. The three-medium heat exchanger endothermic agent outlet pipeline communicates with the LNG storage tank endothermic agent inlet pipeline and the first endothermic agent heat exchange pipeline through a second electromagnetic three-way valve. A endothermic agent circulation pump is also installed on the three-medium heat exchanger endothermic agent outlet pipeline. A cavity is provided inside the shell, and an endothermic agent with gas-liquid conversion characteristics is contained in the cavity. The endothermic agent includes a gaseous phase endothermic agent in a gaseous state and a liquid phase endothermic agent in a liquid state, and the gaseous and liquid states of the endothermic agent can be converted into each other. The inlet end of the cold storage heat exchanger communicates with the LNG storage tank, and the outlet end of the cold storage heat exchanger communicates with the cold storage pipeline outlet pipe. The endothermic agent outlet pipeline communicates with the second main medium pipeline. The cold storage heat exchanger is located in the cavity and is in full contact with the gaseous phase endothermic agent, and the lower heat exchanger is located in the cavity and is in full contact with the liquid phase endothermic agent; An air-conditioning refrigeration unit including a fan coil heat exchange unit and a secondary coolant circulation pump. The inlet end of the fan coil heat exchange unit communicates with the outlet end of the lower heat exchanger through a coil inlet pipe. The outlet end of the fan coil heat exchange unit communicates with the inlet end of the secondary coolant circulation pump. The outlet end of the secondary coolant circulation pump communicates with the inlet end of the lower heat exchanger. A secondary coolant is provided in the loop formed by the connection of the lower heat exchanger, the fan coil heat exchange unit and the secondary coolant circulation pump; A control unit, which is connected to the second electromagnetic three-way valve, the endothermic agent circulation pump, the secondary coolant circulation pump and the fan in a controlled manner; The LNG vehicle and ship refrigeration micro-power air-conditioning system also has a function of circulating pressurization and saturation adjustment of the LNG storage tank: The water-bath heat exchanger includes an endothermic agent heating unit, which is connected to the second electromagnetic three-way valve through the first endothermic agent heat exchange pipeline and is connected to the LNG storage tank endothermic agent inlet pipeline through the second endothermic agent heat exchange pipeline; The cold storage agent outlet pipeline of the three-medium heat exchanger is connected to the cold storage agent circulation pump through a manual second stop valve. The cold storage agent circulation pump is connected to the first cold storage agent heat exchange pipeline and the cold storage agent heating unit through a second electromagnetic three-way valve. The cold storage agent heating unit is connected to the cold storage agent cooling unit placed in the LNG storage tank through the second cold storage agent heat exchange pipeline and the LNG storage tank cold storage agent inlet pipeline. The LNG storage tank cold storage agent outlet pipeline is connected to the cold storage agent cooling unit and the three-medium heat exchanger to form a circulating pressurization and saturation adjustment system for the LNG storage tank.

2. The LNG vehicle and ship refrigeration micro-power air conditioning system according to claim 1 further has a micro-power cycle refrigeration function, and is characterized in that: It further includes a power unit, which is communicated with the third main medium pipeline. The third main medium pipeline is communicated with the cold storage pipeline outlet pipe and the second main medium pipeline through a first electromagnetic three-way valve. The first electromagnetic three-way valve is controlled and connected to the control unit. The inlet end of the cold storage heat exchanger is communicated with the first main medium pipeline through the cold storage pipeline inlet pipe. The connection between the cold storage pipeline inlet pipe and the main medium pipeline is located between the manual first stop valve and the water bath heat exchanger. The outlet end of the cold storage heat exchanger is communicated with the third main medium pipeline through the cold storage pipeline outlet pipe and the first electromagnetic three-way valve. The connection between the cold storage pipeline outlet pipe and the third main medium pipeline is located between the second main medium pipeline and the third main medium pipeline. The cold storage agent outlet pipeline of the three-medium heat exchanger is connected to the cold storage agent circulation pump through a manual second stop valve. The cold storage agent circulation pump is connected to the LNG storage tank cold storage agent inlet pipeline through a second electromagnetic three-way valve. The cold storage agent cooling unit is placed in the LNG storage tank, connected to the second electromagnetic three-way valve through the LNG storage tank cold storage agent inlet pipeline, and connected to the three-medium heat exchanger through the LNG storage tank cold storage agent outlet pipeline to form a micro-power circulating cold storage system.

3. The LNG vehicle and ship refrigeration micro-power air conditioning system according to claim 2, wherein: The fan coil heat exchange unit includes a coil heat exchanger, heat exchange fins and the fan. The heat exchange fins are arranged on the coil heat exchanger. The fan is located on one side of the coil heat exchanger. An air outlet is arranged on the other side of the coil heat exchanger. The blowing direction of the fan faces the coil heat exchanger. The inlet end of the coil heat exchanger is communicated with the outlet end of the lower heat exchanger through the coil inlet pipe. The outlet end of the coil heat exchanger is communicated with the secondary coolant circulation pump. A first temperature sensor and a safety valve are arranged on the three-medium heat exchanger. The first temperature sensor is used to monitor the temperature of the liquid-phase cold storage agent. The safety valve is used to automatically jump and relieve pressure when the pressure of the gas-phase cold storage agent exceeds the standard. A third temperature sensor is arranged at the inlet end of the coil heat exchanger. A second temperature sensor is arranged at the outlet end of the coil heat exchanger. A fourth temperature sensor is arranged near the air outlet. The control unit is communicatively connected to the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor.

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