Weather-resistant refrigeration system and permafrost protection method applied to the Qinghai-Tibet Plateau

Abstract

The present invention discloses a weather-resistant refrigeration system and a permafrost protection method applied to the Qinghai-Tibet Plateau, belonging to the field of permafrost protection technology. The refrigeration system includes a plurality of refrigeration units on the ground and a plurality of permafrost coolers in the permafrost. The refrigeration unit is provided with a plateau environmental performance improvement component, and the permafrost cooler is connected to the refrigeration unit; the protection method is to design a refrigeration system according to permafrost, control the refrigeration unit through a control component to cool the refrigerant and then transport it to the permafrost cooler for heat exchange with the permafrost, so that the temperature of the permafrost is reduced. The plateau environmental performance improvement component can make the refrigeration component adapt to the environment of drastic fluctuations in the plateau climate, and improve the weather resistance of the refrigeration system operation; the refrigeration system using an assembled structure is convenient for transportation and installation, and has an adaptive adjustment function for the plateau climate and the permafrost geological environment, ensuring the balance of refrigeration supply and demand and the permafrost protection effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of permafrost engineering in high-cold areas, and in particular relates to a weather-resistant refrigeration system and a permafrost protection method applied to the Qinghai-Tibet Plateau. Background Art

[0002] China's permafrost is mainly distributed in the Qinghai-Tibet Plateau, the "third pole", with an area of ​​about 1.15×106 km 2 . The Qinghai-Tibet Engineering Corridor is home to major projects such as railways, highways, oil pipelines, communication optical cables, and power grids, crossing about 700 km of permafrost. The permafrost on the Qinghai-Tibet Plateau is caused by the high altitude, so the permafrost temperature is high and the sensitivity to thermal melting is strong. The degradation is long-term and hidden. Coupled with the impact of climate warming and engineering activities, some permafrost is in a state of strong degradation. Permafrost degradation can cause uneven settlement, deformation and damage to various structures such as railway and highway roadbeds, bridge pile foundations, abutments, oil pipelines, and power tower foundations. "Protecting frozen soil" is the main principle of engineering construction in permafrost areas, which mainly follows the protection ideas of passive insulation, active cooling, and cooling foundations. Specific measures include high thermal resistance insulation materials, air forced convection air cooling structures, solar radiation reflection structures, heat rods and other structural measures. However, in scenarios where permafrost is severely degraded and emergency rescue is required, existing measures are still unable to quickly cool down the permafrost, especially in the warm season, permafrost cannot be protected in real time, resulting in settlement and damage to roadbeds, bridge abutments, pipelines, and tower foundations. For this reason, mainstream compression refrigeration technology has begun to be introduced to actively transport cold and cool permafrost. For example, patent application number CN201711190185.7 discloses a compression refrigeration system for preventing and controlling permafrost degradation, which is a refrigeration system driven by solar energy and wind energy; patent application number CN202311743133.3 discloses a permafrost area all-season hot rod refrigeration device and construction method, which is a compression refrigeration system driven by solar photovoltaic power generation and has multiple refrigeration sections.

[0003] The main problems in the two patent documents disclosed above are: For compression refrigeration systems, the design is based on a rated operating environment to select components and calculate the refrigerant charge. However, the actual operating environment will deviate from the rated operating environment. When the difference between the two is large, the actual heat exchange fluctuation range is large, which will make the refrigerant phase change rate too low, and the condenser "gas leakage" and evaporator "liquid leakage" phenomenon will occur, which will cause the condenser high pressure and evaporator low pressure to deviate from the rated operating design value, and ultimately lead to poor operating efficiency of the refrigeration system and compressor "liquid hammer" failure. When applied to the protection of permafrost on the Qinghai-Tibet Plateau, the average altitude of the Qinghai-Tibet Plateau is above 4,000 meters, the climate is changeable, the temperature fluctuates greatly, the daily temperature difference can reach 20 to 30 ° C, and the annual average temperature of permafrost is between -2.6 and 0 ° C. This plateau environment with a large temperature change range and high frequency will lead to weather resistance problems such as low refrigeration efficiency, high failure rate, and low service life of the refrigeration system; on the other hand, the traditional complete refrigeration system is inconvenient to disassemble and difficult to repair. It can be seen that improving the weather resistance and maintenance convenience of the refrigeration system is the key to ensuring the practicality of permafrost refrigeration protection technology. Summary of the invention

[0004] The purpose of the present invention is to provide a weather-resistant refrigeration system and a permafrost protection method for use in the Qinghai-Tibet Plateau, aiming to solve the technical problems of high failure rate, poor weather resistance and inconvenient maintenance of the refrigeration system used for protecting permafrost in the prior art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau, the refrigeration system comprising a plurality of refrigeration units and a plurality of permafrost cooling devices, the refrigeration units being arranged on the ground, and the permafrost cooling devices being arranged in the permafrost underground; the permafrost cooling devices being connected to the refrigeration units via a medium conveying assembly, the refrigeration units cooling the refrigerant and conveying the refrigerant to the permafrost cooling devices via the medium conveying assembly, the refrigerant in the permafrost cooling devices exchanging heat with the permafrost to reduce the temperature of the permafrost;

[0007] The refrigeration unit includes a cabinet and a refrigeration component and a control component inside it. The refrigeration component includes a high-pressure conversion unit, a low-pressure refrigeration unit and a plateau environment performance improvement component. The plateau environment performance improvement component includes a high-pressure regulation module and a low-pressure regulation module. The high-pressure regulation module is connected to the high-pressure conversion unit, and the low-pressure regulation module is connected to the low-pressure refrigeration unit; the high-pressure conversion unit and the low-pressure refrigeration unit are respectively connected to the permafrost cooling device through a medium conveying component; the control component is used to control the operation of the refrigeration component and monitor the temperature and pressure of the refrigeration component and the inlet and outlet pressures of the permafrost cooling device.

[0008] Furthermore, the high-pressure conversion unit includes a compressor, an oil separator, a condenser, a fan and a high-pressure liquid storage tank, and the high-pressure regulating module includes a high-pressure gas-liquid separator, a high-pressure gas storage tank, a three-way connector I and a regenerator. The outlet of the compressor is connected to the oil separator, and the outlet of the oil separator is connected to the inlet of the condenser through the three-way connector I. The outlet of the condenser is connected to the inlet of the high-pressure gas-liquid separator, and the liquid outlet of the high-pressure gas-liquid separator is connected to the inlet of the high-pressure liquid storage tank, and the outlet of the high-pressure liquid storage tank is connected to the inlet of the flow control valve of the low-pressure refrigeration unit; the gas outlet of the high-pressure gas-liquid separator is connected to the inlet of the high-pressure gas storage tank, and the outlet of the high-pressure gas storage tank is connected to a joint of the three-way connector I through a gas reflux pipe, and the other two joints of the three-way connector I are respectively connected to the pipeline between the oil separator and the condenser; the gas outlet of the low-pressure gas-liquid separator of the low-pressure regulating module is connected to the inlet of the regenerator, and the outlet of the regenerator is connected to the inlet of the compressor; the regenerator and the fan are respectively arranged on both sides of the condenser, and the regenerator is used to absorb the heat released by the condenser.

[0009] Furthermore, the low-pressure refrigeration unit includes a flow control valve, a drying filter and a throttle, and the low-pressure regulating module includes a low-pressure gas-liquid separator, a low-pressure liquid storage tank, a liquid return pipe and a three-way connector II. The outlet of the flow control valve is connected to the inlet of the drying filter through the three-way connector II, the outlet of the drying filter is connected to the inlet of the throttle, and the outlet of the throttle is connected to the inlet of the low-pressure outflow valve; the inlet of the low-pressure gas-liquid separator is connected to the refrigerant outlet of the permafrost cooling device through the high-pressure inlet valve of the control component, the liquid outlet of the low-pressure gas-liquid separator is connected to the inlet of the low-pressure liquid storage tank, the outlet of the low-pressure liquid storage tank is connected to one of the joints of the three-way connector II through the liquid return pipe, and the other two joints of the three-way connector II are respectively connected to the pipeline between the drying filter and the flow control valve.

[0010] Furthermore, the control component includes a low-pressure outflow valve, a high-pressure inflow valve, a temperature sensor, a pressure sensor, a controller and an actuator, the low-pressure outflow valve and the high-pressure inflow valve are arranged in parallel in the middle of the cabinet, the inlet of the low-pressure outflow valve is connected to the refrigerant outlet of the low-pressure refrigeration unit, the outlet of the low-pressure outflow valve is connected to the refrigerant inlet of the permafrost cooling device, the inlet of the high-pressure inflow valve is connected to the refrigerant outlet of the permafrost cooling device, and the outlet of the high-pressure inflow valve is connected to the inlet of the low-pressure gas-liquid separator of the low-pressure refrigeration unit; the temperature sensor and the pressure sensor are both arranged in the refrigeration component, and the controller and the actuator are correspondingly arranged in the middle of the inner side of the cabinet; the low-pressure outflow valve, the high-pressure inflow valve, the temperature sensor, the pressure sensor, the refrigeration component and the actuator are all connected to the controller, and the actuator is used to execute the control instructions of the controller to realize human-computer interaction.

[0011] Furthermore, the permafrost cooling device includes a cold storage and heat transfer enhancement component and an end protection component, the cold storage and heat transfer enhancement component includes a sleeve and an evaporative cooling tube inside the sleeve, the sleeve is arranged in the permafrost, the sleeve is a hollow tube body with a sealed end, the evaporative cooling tube is spirally arranged inside the sleeve, the space between the evaporative cooling tube and the sleeve is filled with heat transfer fluid, and the refrigerant in the evaporative cooling tube exchanges heat with the permafrost through the heat transfer fluid; the open end of the sleeve is connected to the end protection component, and the medium conveying pipe of the medium conveying component passes through the end protection component and is connected to the evaporative cooling tube.

[0012] Furthermore, the end protection assembly includes a flange base and a flange buckle cover, the flange base is fixedly mounted on the upper end of the sleeve, the flange buckle cover is a hollow shell, the flange buckle cover is bolted to the flange base on all sides, and the inner cavity formed by the flange buckle cover and the flange base is filled with polyurethane foam glue.

[0013] Furthermore, the medium conveying component includes an outer sleeve, an insulation pipe and a medium conveying pipe from the outside to the inside. The insulation pipe is fixed to the outside of the medium conveying pipe by wrapping it with a rubber-plastic cable tie, and the outer sleeve is sleeved on the outside of the insulation pipe; the medium conveying pipe is used to connect the refrigeration component with the permafrost cooler; the medium conveying pipe is a copper pipe, the insulation pipe is a high-density rubber-plastic insulation pipe, and the outer sleeve is a PVC pipe.

[0014] Furthermore, a cabinet door that can be opened and closed is provided on one side of the cabinet, an upper support plate and a middle support plate are provided at intervals in the middle position of the interior of the cabinet, and a lower support plate is provided at the bottom, and the two sides of the upper support plate and the middle support plate are respectively connected to the two side panels adjacent to the cabinet door; a cooling output window for the medium conveying component to pass through is provided on the side panel opposite to the cabinet door; and air distributors for heat dissipation are provided on the upper parts of the side panels on both sides of the cabinet door;

[0015] The control assembly is arranged on the middle support plate, the high-pressure conversion unit and the high-pressure regulating module are arranged on the upper support plate, and the low-pressure refrigeration unit and the low-pressure regulating module are arranged on the lower support plate.

[0016] Furthermore, the inner walls of the side panels on both sides of the cabinet door are respectively provided with guide rails that slide with the upper support plate, the middle support plate and the lower support plate. The cabinet is made of stainless steel plate, the cold output window is an open and close structure, and the air distributor is a shutter with rain and dustproof functions.

[0017] The present invention also provides a permafrost protection method, which uses the above-mentioned weather-resistant refrigeration system applied to the Qinghai-Tibet Plateau to cool the permafrost, comprising the following steps:

[0018] S1: Permafrost scenario investigation;

[0019] S2: Design and prepare refrigeration system;

[0020] S3: Install and debug the refrigeration system;

[0021] S4: Dynamically control the refrigeration system. The operation control method of the refrigeration system is as follows:

[0022] (1) Setting the first refrigeration temperature on the actuator, which is set to -20°C lower than the average temperature of permafrost, and starting the refrigeration system;

[0023] (2) Normal operation mode setting of the refrigeration system: the flow control valve in the low-pressure refrigeration unit is opened to 50%, and the inlets of the three-way connector I and the three-way connector II are closed;

[0024] (3) Adaptive dynamic adjustment of the refrigeration system: The controller controls the monitoring frequency of the compression chamber temperature of the compressor and the motor temperature, and controls the monitoring frequency of the inlet and outlet pressures of the condenser, the inlet and outlet pressures of the high-pressure inlet valve, and the low-pressure outflow valve. The controller determines the operating status of the refrigeration system.

[0025] (4) Adjusting the output temperature of the refrigeration system: When the permafrost temperature monitoring shows that the cooling diffusion and the cooling range between adjacent permafrost coolers have been circled, reset the second refrigeration temperature to -10°C lower than the average permafrost temperature;

[0026] (5) The refrigeration system continues to perform adaptive dynamic adjustment until the permafrost cools to the target temperature.

[0027] Furthermore, in step (3), the adaptive dynamic adjustment method of the refrigeration system is as follows:

[0028] The controller controls the compressor compression chamber temperature to be monitored once at 0, 10, 20, 30, 40, and 50 minutes per hour, the compressor motor temperature to be monitored once at 5, 15, 25, 35, 45, and 55 minutes per hour, and the control pressure to be monitored once every 10 minutes. The controller determines the operating status of the refrigeration system and executes the following commands:

[0029] 1) When the monitoring temperature of the compression chamber of the compressor exceeds the set range, when the monitoring temperature is 90-95℃, the flow control valve opening is set to 60%; when the monitoring temperature is 95-100℃, the flow control valve opening is set to 70%; when the monitoring temperature is 100-105℃, the flow control valve opening is set to 80%; when the monitoring temperature is 105-110℃, the flow control valve opening is set to 90%; after the monitoring temperature exceeds 110℃, the compressor will stop for 10 minutes;

[0030] 2) When the monitored temperature of the compressor motor exceeds the set range, the flow control valve opening is set to the current value - 5%; when the monitored temperature is 95-100℃, the flow control valve opening is set to the current value - 10%; when the monitored temperature is 100-105℃, the flow control valve opening is set to the current value - 15%; when the monitored temperature is 105-110℃, the flow control valve opening is set to the current value - 20%; after the monitored temperature exceeds 110℃, the compressor will stop for 10 minutes;

[0031] 3) When the pressure drop value inside the condenser exceeds the set range, open the inlet of the three-way connector I, otherwise close it;

[0032] 4) When the pressure drop inside the evaporative refrigeration pipe exceeds the set range, open the inlet of the three-way connector II, otherwise close it.

[0033] Compared with the prior art, the present invention has the following technical advances:

[0034] The present invention can make the refrigeration components adapt to the environment of drastic fluctuations in the plateau climate through the plateau environmental performance improvement component, avoid the "gas leakage" of the condenser and the "liquid leakage" of the evaporative refrigeration tube caused by insufficient refrigerant phase change rate, ensure the operating efficiency of the refrigeration system and avoid the "liquid hammer" failure of the compressor, and improve the weather resistance of the operating function of the refrigeration system. The refrigeration system adopts an assembled structure, which is convenient for split transportation, easy on-site installation, good scene adaptability, reliable operation, and high degree of automation; the permafrost protection method has an adaptive intelligent adjustment function for the plateau climate and permafrost geological environment. The present invention can reasonably design the number of refrigeration systems, on-site layout plans and component selection according to the actual protection needs of permafrost, to ensure the balance of cooling capacity supply and demand and the permafrost protection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0036] In the attached picture:

[0037] Figure 1 A schematic diagram of an application state of a weather-resistant refrigeration system applied to the Qinghai-Tibet Plateau provided by an embodiment of the present invention;

[0038] Figure 2 is an appearance diagram of a cabinet in an embodiment of the present invention;

[0039] Figure 3 Schematic diagram of the internal structure of a cabinet in an embodiment of the present invention;

[0040] Figure 4Schematic diagram of the structural arrangement on the upper support plate inside the cabinet in an embodiment of the present invention;

[0041] Figure 5 Schematic diagram of the structural arrangement on the middle support plate inside the cabinet in an embodiment of the present invention;

[0042] Figure 6 Schematic diagram of the structural arrangement on the lower support plate inside the cabinet in an embodiment of the present invention;

[0043] Figure 7 This is a schematic diagram of the structure of a refrigeration assembly in an embodiment of the present invention;

[0044] Figure 8 This is a schematic diagram of the structure of a permafrost cooling device in an embodiment of the present invention;

[0045] Fig. 9 Schematic diagram of the connection between the refrigeration unit and the permafrost cooling device in the embodiment of the present invention

[0046] Fig.10 for Fig. 9 The backward schematic diagram in ;

[0047] In the figure:

[0048] 1-refrigeration unit; 2-permafrost cooling device; 3-cabinet; 401-upper pallet, 402-middle pallet, 403-lower pallet; 5-cabinet door; 6-side panel; 7-cold output window; 8-air distributor; 9-compressor; 10-oil separator; 11-condenser; 12-fan; 13-high-pressure liquid storage tank; 14-flow control valve; 15-drying filter; 16-throttle; 17-evaporative cooling pipe; 18-low-pressure outflow valve ; 19-high-pressure inflow valve; 20-high-pressure gas-liquid separator; 21-high-pressure gas storage tank; 22-gas return pipe; 2301-three-way connector I, 2302-three-way connector II; 24-regenerator; 25-low-pressure gas-liquid separator; 26-low-pressure liquid storage tank; 27-liquid return pipe; 28-casing; 29-flange base; 30-flange buckle cover; 31-controller; 32-actuator; 33-roadbed; 34-permafrost foundation. DETAILED DESCRIPTION

[0049] The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. The embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0050] like Figure 1 , Figure 3 and Figure 7As shown, an embodiment of the present invention provides a weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau, the refrigeration system comprising a plurality of refrigeration units 1 and a plurality of permafrost cooling devices 2, the refrigeration unit 1 being arranged on the ground, the permafrost cooling device 2 being arranged in the permafrost underground; the permafrost cooling device 2 being connected to the refrigeration unit 1 via a medium conveying component, the refrigeration unit 1 cooling the refrigerant and then conveying the refrigerant to the permafrost cooling device 2 via the medium conveying component, the refrigerant in the permafrost cooling device 2 exchanges heat with the permafrost to reduce the temperature of the permafrost; the refrigeration unit 1 comprises a cabinet 3 and a refrigeration component and a control component therein, the system The cold assembly includes a high-pressure conversion unit, a low-pressure refrigeration unit and a plateau environmental performance improvement assembly, wherein the plateau environmental performance improvement assembly includes a high-pressure regulating module and a low-pressure regulating module, wherein the high-pressure regulating module is connected to the high-pressure conversion unit, and the low-pressure regulating module is connected to the low-pressure refrigeration unit; the high-pressure conversion unit and the high-pressure regulating module, the low-pressure refrigeration unit and the low-pressure regulating module are respectively arranged at the upper part and the lower part of the cabinet 3, wherein the high-pressure conversion unit and the low-pressure refrigeration unit are respectively connected to the permafrost refrigeration device 2 through the medium conveying assembly; the control assembly is used to control the operation of the refrigeration assembly, and monitor the temperature and pressure of the refrigeration assembly and the inlet and outlet pressures of the permafrost refrigeration device 2. The plateau environmental performance improvement assembly can make the refrigeration assembly adapt to the environment of drastic fluctuations in the plateau climate, avoid the occurrence of "gas leakage" of the condenser and "liquid leakage" of the evaporative refrigeration pipe caused by insufficient refrigerant phase change rate, ensure the operating efficiency of the refrigeration system and avoid the "liquid hammer" failure of the compressor, and improve the weather resistance of the operating function of the refrigeration system.

[0051] Among them, the refrigerant selected is R410A, which is an environmentally friendly refrigerant. The beneficial effect is that it can maintain excellent refrigeration effect in low-pressure and low-oxygen environments, and adapt to the low-pressure and low-oxygen environmental conditions of the plateau; at the same time, the composition does not contain chlorine, has no destructive effect on the ozone layer, and is beneficial to plateau environmental protection.

[0052] Figure 1 As a specific application example of the present invention, the refrigeration units 1 are arranged in two rows on both sides of the roadbed 33, and the permafrost coolers 2 are arranged in two rows in the permafrost foundation 34 below the roadbed 33. In the specific design, the output performance of the refrigeration assembly is a refrigeration temperature range of 0 to -30°C and a refrigeration power range of 100 to 500W.

[0053] In a specific embodiment of the present invention, Figure 3 , 4As shown in , 7, the high-pressure conversion unit includes a compressor 9, an oil separator 10, a condenser 11, a fan 12 and a high-pressure liquid storage tank 13, the high-pressure regulating module includes a high-pressure gas-liquid separator 20, a high-pressure gas storage tank 21, a three-way connector I 2301 and a regenerator 24, the outlet of the compressor 9 is connected to the oil separator 10, the outlet of the oil separator 10 is connected to the inlet of the condenser 11 through the three-way connector I 2301, the outlet of the condenser 11 is connected to the inlet of the high-pressure gas-liquid separator 20, the liquid outlet of the high-pressure gas-liquid separator 20 is connected to the inlet of the high-pressure liquid storage tank 13, and the outlet of the high-pressure liquid storage tank 13 is connected to the flow rate of the low-pressure refrigeration unit. The inlet of the control valve 14 is connected; the gas outlet of the high-pressure gas-liquid separator 20 is connected to the inlet of the high-pressure gas storage tank 21, and the outlet of the high-pressure gas storage tank 21 is connected to a joint of the three-way connector Ⅰ2301 through the gas reflux pipe 22, and the other two joints of the three-way connector Ⅰ2301 are respectively connected to the pipeline between the oil separator 10 and the condenser 11; the gas outlet of the low-pressure gas-liquid separator 25 of the low-pressure regulating module is connected to the inlet of the regenerator 24, and the outlet of the regenerator 24 is connected to the inlet of the compressor 9; the regenerator 24 and the fan 12 are respectively arranged on both sides of the condenser 11, and the regenerator 24 is used to absorb the heat released by the condenser 11. The above-mentioned high-pressure regulating module can separate a small amount of gaseous refrigerant that has not been completely liquefied from the refrigerant at the outlet of the condenser 11 before entering the drying filter 15 of the low-pressure refrigeration unit, and store the separated gaseous refrigerant in the high-pressure gas storage tank 21. The opening state of the inlet of the three-way connector I2301 is controlled according to the preset adaptive dynamic adjustment scheme, so that the gaseous refrigerant can dynamically flow back to the condenser 11 through the gas return pipe 22, so that the gaseous refrigerant can continue to dissipate heat and liquefy, thereby preventing the "gas leakage" failure of the condenser 11 and improving the refrigerant circulation ratio and the effective utilization rate of the input power of the compressor 9.

[0054] The specific selection of each component in the above-mentioned high-voltage conversion unit and high-voltage regulation module is as follows:

[0055] The compressor 9 adopts a reciprocating medium back pressure compressor, which plays the role of sucking, compressing and conveying refrigerant vapor. Its function is to elevate low-pressure refrigerant gas to high-pressure gas. Its inlet has a low-pressure suction effect and its outlet has a high-pressure ejection effect. The compressor 9 includes a compression chamber and a motor. The motor is driven by 220V AC, and the input power is between 100 and 500W, with a specification of 50W.

[0056] The oil separator 10 is a filter-type oil separator, and its function is to separate the lubricating oil in the high-pressure refrigerant vapor discharged from the compressor 9 to ensure the safe and efficient operation of the refrigeration component.

[0057] The condenser 11 adopts a forced convection air cooling condenser, and its structural form is a coil sleeve type. Its selection scheme is: the condensing power is 1.5 times the input power of the compressor 9. Its function is to quickly dissipate the heat of the high-temperature and high-pressure gaseous refrigerant output by the compressor 9 and then liquefy it. Its beneficial effects are: first, the structure is compact, and the internal installation space requirements of the cabinet are low, which is conducive to reducing the size of the cabinet; second, the dustproof performance is good, and it can adapt to the strong wind and dust weather common in the plateau; third, with the auxiliary action of the axial flow fan 12, the low temperature air conditions of the Qinghai-Tibet Plateau can be effectively utilized, and the heat dissipation efficiency is fast; fourth, the heat dissipation airflow temperature is high, which can cooperate with the plateau environment performance improvement components to effectively improve the output performance of the refrigeration components.

[0058] The fan 12 is an external rotor axial flow fan, and its selection scheme is: the input power is 1 / 5 of the input power of the compressor 9, and the geometric structure and size are consistent with the cross-sectional shape of the condenser 11. Its function is to induce the cold air outside the cabinet to flow into the cabinet 3, so that the condenser 11 can efficiently dissipate heat by convection.

[0059] The high-pressure liquid storage tank 13 is used to store the liquid refrigerant after liquefaction by the condenser 11. It adopts a pressure-resistant sealed container with a thermal insulation layer on the outer surface. The selection scheme is: the volume is 1.5 times the liquid refrigerant charge.

[0060] The high-pressure gas-liquid separator 20 adopts a baffle separation type gas-liquid separator, and the outlet is divided into an upper gas outlet and a lower liquid outlet. It is mainly suitable for high-pressure containers and has a good separation effect on media with a large liquid ratio and a small gas ratio. The beneficial effect of the high-pressure gas-liquid separator 20 is to separate a small amount of gaseous refrigerant that has not been completely liquefied from the refrigerant at the outlet of the condenser 11 of the high-pressure module of the refrigeration component before entering the drying filter 15 of the low-pressure module, thereby preventing the condenser 11 from "gas leakage" failure and improving the effective utilization rate of the input power of the compressor 9.

[0061] The high-pressure gas storage tank 21 is a pressure-resistant sealed container with a heat-insulating layer on the outer surface, and its volume is 1 / 3 of the inner volume of the condenser 11. The gas return pipe 22 is a copper tube with an outer diameter of 8 mm and a wall thickness of 1 mm, in order to reduce the gas flow resistance. The high-pressure gas storage tank 21, the condenser 11 and the oil separator 10 are connected by a three-way connector 12301. The three-way connector 12301 is also used to prevent the reverse flow of gaseous refrigerant, in order to prevent gas pressure loss and ensure the regulation effect of the high-pressure regulation module.

[0062] The function of the regenerator 24 is to absorb the heat released by the condenser 11 after the refrigerant in the evaporating refrigeration pipe 17 passes through the low-pressure regulating module and before entering the compressor 9. On the one hand, it prevents the refrigerant from remaining in the liquid medium and eliminates the hidden danger of liquid hammer in the compressor 9; on the other hand, it increases the temperature of the gaseous refrigerant at the inlet of the compressor 9, increases the compression ratio of the compressor 9, and increases the exhaust temperature of the compressor 9, thereby improving the condensation and liquefaction effect of the condenser 11 and improving the overall operating efficiency of the refrigeration component. The selection scheme is: a serpentine tube row formed by bending a copper tube with an outer diameter of 6mm, a wall thickness of 1mm, and a length of 2m, and the structural shape and size are equivalent to the cross-section of the condenser 11.

[0063] In a specific embodiment of the present invention, Figure 3 , 6 , 7, the low-pressure refrigeration unit includes a flow control valve 14, a drying filter 15 and a throttle 16, the low-pressure regulating module includes a low-pressure gas-liquid separator 25, a low-pressure liquid storage tank 26, a liquid return pipe 27 and a three-way connector II 2302, the inlet of the low-pressure gas-liquid separator 25 is connected to the refrigerant outlet of the permafrost cooling device 2 through the high-pressure inflow valve 19 of the control component, the inlet of the flow control valve 14 is connected to the outlet of the high-pressure liquid storage tank 13, and the outlet of the flow control valve 14 is connected to the drying filter 15 through the three-way connector II 2302. The inlet of the low-pressure gas-liquid separator 25 is connected, the outlet of the dry filter 15 is connected to the inlet of the throttle 16, and the outlet of the throttle 16 is connected to the inlet of the low-pressure outflow valve 18; the gas outlet of the low-pressure gas-liquid separator 25 is connected to the inlet of the regenerator 24, and the liquid outlet of the low-pressure gas-liquid separator 25 is connected to the inlet of the low-pressure liquid storage tank 26, and the outlet of the low-pressure liquid storage tank 26 is connected to one joint of the three-way connector II 2302 through the liquid reflux pipe 27, and the other two joints of the three-way connector II 2302 are respectively connected to the pipeline between the dry filter 15 and the flow control valve 14. The above-mentioned low-pressure regulating module can separate a small amount of liquid refrigerant that has not been completely vaporized from the refrigerant at the outlet of the evaporative refrigeration pipe 17 before it enters the compressor 9 through the high-pressure inlet valve 19 of the control component, and store the separated liquid refrigerant in the low-pressure liquid storage tank 26. The opening state of the inlet of the three-way connector II2302 is controlled according to the preset adaptive dynamic adjustment scheme, so that the liquid refrigerant is dynamically returned to the drying filter 15 through the liquid return pipe 27, so that the liquid refrigerant continues to absorb heat and refrigerate, thereby preventing the evaporative refrigeration pipe 17 from "liquid leakage" and the compressor 9 from "liquid hammer" failures, and also improving the refrigerant circulation ratio and the effective utilization rate of the input power of the compressor 9.

[0064] The specific selection of each component in the above-mentioned low-pressure refrigeration unit and low-pressure regulation module is as follows:

[0065] The function of the drying filter 15 is to filter impurities generated during the refrigeration cycle and ensure the purity of the refrigerant. The selection scheme is: to use a zeolite molecular sieve drying filter, which has the beneficial effects of strong adsorption and high adsorption ratio, and can effectively prevent the deterioration of the refrigeration component material in the plateau environment from causing "dirty blockage" in the internal pipeline.

[0066] The function of the throttle 16 is to throttle and reduce the pressure of the refrigerant, and at the same time control and adjust the refrigerant flow rate. Its selection scheme is: use an external balanced thermal expansion valve and connect it to the outlet of the evaporative refrigeration pipe 17. Its beneficial effect is that it can not only dynamically adjust the refrigerant flow rate, but also reduce the flow rate regulation sensitivity. This adapts to the special scenario where the evaporative refrigeration pipe 17 is buried in the permafrost layer and its internal pressure loss along the way is large and the refrigeration temperature changes greatly, which is beneficial to ensure the volume utilization rate of the evaporative refrigeration pipe 17.

[0067] The function of the flow control valve 14 is to control the circulation flow of the refrigerant. An electromagnetic flow control valve is used, and its selection scheme is: the inner diameter of the flow is 5.6 mm. The flow control valve 14 cooperates with the throttle 16 to control the refrigerant flow and pressure. The beneficial effect is that compared with a single control component, the robustness of the refrigerant circulation control performance is effectively improved.

[0068] The low-pressure gas separator 25 adopts a filling separation type gas-liquid separator, and the outlet is divided into an upper gas outlet and a lower liquid outlet. It is suitable for low-pressure containers and has a good separation effect on media with a small proportion of liquid and a large proportion of gas. The beneficial effect of the low-pressure gas-liquid separator 25 is to separate a small amount of liquid refrigerant that has not been completely vaporized from the refrigerant at the outlet of the evaporative refrigeration pipe 17 of the low-pressure module of the refrigeration component before it enters the compressor 9 through the high-pressure inflow valve 19 of the high-pressure module, thereby preventing the evaporative refrigeration pipe 17 from "liquid leakage" and the compressor 9 from "liquid hammer" failures, thereby improving the refrigeration efficiency, reliability and service life of the refrigeration system.

[0069] The low-pressure liquid storage tank 26 is a pressure-resistant sealed container with a heat-insulating layer on the outer surface, and its volume is 1 / 5 of the refrigerant charge. The liquid return pipe 27 is a copper pipe with an outer diameter of 4mm and a wall thickness of 1mm, the purpose of which is to increase the liquid flow speed, maintain the liquid flow inertia, and make it return smoothly.

[0070] The low-pressure liquid storage tank 26, the flow control valve 14 and the filter drier 15 are connected by a three-way connector II2302. The three-way connector II2302 is used to prevent the liquid refrigerant from flowing in reverse, so as to prevent the thermal expansion valve from frosting due to excessive liquid supply and ensure the regulating effect of the low-pressure regulating module.

[0071] In a specific embodiment of the present invention, Figure 2 , 35, the control component includes a low-pressure outflow valve 18, a high-pressure inflow valve 19, a temperature sensor, a pressure sensor, a controller 31 and an actuator 32, the low-pressure outflow valve 18 and the high-pressure inflow valve 19 are arranged in parallel on the middle support plate 402 in the middle of the cabinet 3, the inlet of the low-pressure outflow valve 18 is connected to the refrigerant outlet of the low-pressure refrigeration unit, the outlet of the low-pressure outflow valve 18 is connected to the refrigerant inlet of the permafrost cooling device 2, the inlet of the high-pressure inflow valve 19 is connected to the refrigerant outlet of the permafrost cooling device 2, the The outlet of the high-pressure inflow valve 19 is connected to the inlet of the low-pressure gas-liquid separator 25 of the low-pressure refrigeration unit; the temperature sensor and the pressure sensor are both arranged in the refrigeration assembly, and the controller 31 and the actuator 32 are correspondingly arranged between the upper support plate 401 and the middle support plate 402 on the inner side of the cabinet door 5 of the cabinet 3; the low-pressure outflow valve 18, the high-pressure inflow valve 19, the temperature sensor, the pressure sensor, the refrigeration assembly and the actuator 32 are all connected to the controller 31, and the actuator 32 can execute the control instructions of the controller 31 to realize human-computer interaction. The selection of each component is as follows:

[0072] The low-pressure outflow valve 18 and the high-pressure inflow valve 19 are both low-temperature stop valves, which are opened and closed manually. Their functions are: they are used for refrigerant management during the installation and maintenance of the refrigeration unit, and are suitable for temperatures below -50°C. The joints are threaded and sealed.

[0073] The temperature sensor and the pressure sensor are connected in parallel with the controller 31 through a signal line. The function of the temperature sensor is to monitor the compression chamber temperature of the compressor 9 and the temperature of the motor. A temperature-resistant PT1000 sensor with a range of -50 to 150°C is used. The pressure sensors are arranged at the inlet and outlet of the condenser 11 to monitor the absolute value of the pressure and the pressure drop at the inlet and outlet of the condenser 11; at the same time, pressure sensors are arranged at the inlet of the high-pressure inflow valve 19 and the low-pressure outflow valve 18 to monitor the absolute value of the pressure and the pressure drop at the inlet and outlet of the evaporative refrigeration pipe 17.

[0074] The controller 31 collects the monitoring values ​​of the temperature sensor and the pressure sensor, determines the operating status of the refrigeration component, and gives control instructions, using a programmable logic PLC module. The actuator 32 executes the control instructions of the controller 31 and provides a human-computer interaction function, using an HMI configuration screen.

[0075] The actuator 32 is connected to the flow control valve 14, the three-way connector I2301, and the three-way connector II2302 through the signal line; the flow controller 14, the three-way connector I2301, and the three-way connector II2302 can provide the communication signal and the power required for the actuation through the signal line. In terms of power, the external power supply (220V) is connected to the actuator 32 through the power line, and the actuator 32 is connected to the compressor 9 and the axial flow fan 12.

[0076] When designing specifically, Figure 8 As shown, the permafrost cooling device 2 includes a cold storage and heat transfer enhancement component and an end protection component. The cold storage and heat transfer enhancement component includes a sleeve 28 and an evaporative cooling tube 17 inside the sleeve 28. The sleeve 28 is arranged in the permafrost foundation 34. The sleeve 28 is a hollow tube body with a sealed end. The evaporative cooling tube 17 is spirally arranged inside the sleeve 28. A heat transfer liquid is filled between the evaporative cooling tube 17 and the sleeve 28. The refrigerant in the evaporative cooling tube 17 exchanges heat with the permafrost through the heat transfer liquid; the open end of the sleeve 28 is connected to the end protection component, and the medium conveying pipe of the medium conveying component passes through the end protection component and is connected to the evaporative cooling tube 17. The end protection assembly includes a flange base 29 and a flange cover 30. The flange base 29 is fixedly mounted on the upper end of the sleeve 28. The flange cover 30 is a hollow shell. The flange cover 30 is connected to the flange base 29 by bolts. The inner cavity formed by the flange cover 30 and the flange base 29 is filled with polyurethane foam. Figure 1 , 9 , as shown in 10. The specific selection of each component is as follows:

[0077] The evaporative cooling tube 17 is made of a copper tube with an outer diameter of 6mm, a wall thickness of 1mm, and an inner diameter of 4mm. Since the copper tube is a flexible tube and can be bent freely, according to the needs of the permafrost foundation 34 protection scenario, it is suitable to be designed as a columnar structure that is convenient for mechanized drilling and long-distance deployment, so as to go deep underground to protect the permafrost at a designated location. The evaporative cooling tube adopts a spiral structure so that the spiral diameter and pitch can be adjusted autonomously to form column sizes of different diameters and heights. The length of the evaporative cooling tube is matched according to the power of the compressor 9. When the input power of the compressor 9 is 100W, the matching length is 30m. After that, the ratio of the length increase of the evaporative cooling tube 17 to the input power increase of the compressor 9 is 1m / 10W. Its function is to make the refrigerant evaporate and gasify quickly, absorb heat efficiently, and produce a refrigeration effect.

[0078] The casing 28 is made of stainless steel. The function of the stainless steel casing 28 is to protect the evaporative cooling tube 17 to prevent deformation or damage caused by external loads such as external forces during the installation process and permafrost stress during construction and use. Beneficial effects also include that the stainless steel casing can resist the influence of various erosion effects such as underground frozen soil temperature, moisture, acid, alkali, salt, etc., has a long service life, and has good heat transfer performance. The selection scheme is to use 210 stainless steel pipe with a wall thickness of 2.0mm, the bottom end of the stainless steel pipe is sealed, and a 5cm long external threaded pipe with the same diameter as the stainless steel pipe and a threaded thread cover are welded on the top.

[0079] The function of the heat transfer fluid is to transfer and store the cold output by the evaporative cooling tube 17, forming a cascade utilization process of cold energy and increasing the uniformity of the cold flow density along the stainless steel casing of the permafrost cooling device. The selection scheme of the heat transfer fluid is to use an alcohol heat transfer fluid with a freezing point temperature of -25°C.

[0080] The flange base 29 is a set of stainless steel pipes with an inner diameter of 116 mm, one end is open, and the other end is welded with a stainless steel sheet with a side length of 240 mm. The flange buckle cover 30 is a rectangular buckle cover with a side length of 200 mm, a height of 100 mm, and a 20 mm edge around. The flange base 29 is sleeved on the top of the stainless steel sleeve 28, and the flange buckle cover 30 and the flange base 29 are bolted. The function is to protect the top of the stainless steel sleeve 28, mark the position of the underground permafrost cold transporter 2 during use, prevent external human damage, and prevent precipitation, dust and other foreign objects from intruding. The flange buckle cover 30 is filled with polyurethane foam glue, and its function is to prevent the cold from overflowing into the atmospheric environment, increase the input ratio of cold to permafrost, and improve the effective utilization rate of cold.

[0081] As a preferred structure, the medium conveying assembly includes an outer sleeve, an insulation pipe and a medium conveying pipe from the outside to the inside. The insulation pipe is fixed to the outside of the medium conveying pipe by wrapping with a rubber-plastic tie, and the outer sleeve is sleeved on the outside of the insulation pipe; the medium conveying pipe is used to connect the refrigeration assembly and the permafrost cooling device; the medium conveying pipe is a copper pipe, the insulation pipe is a high-density rubber-plastic insulation pipe, and the outer sleeve is a PVC pipe. The function of the insulation pipe is to prevent the loss of cold along the copper pipe between the surface refrigeration unit and the underground permafrost cooling device. A high-density rubber-plastic insulation pipe with an inner diameter of 6mm and an outer diameter of 36mm is used, and the outside is wrapped and shaped by a rubber-plastic tie; the function of the PVC outer sleeve is to protect the insulation pipe and its internal copper pipe to prevent damage from external loads and weathering from the natural environment. A 75mm outer diameter PVC pipe for building drainage is used, which is corrosion-resistant and weathering-resistant and can adapt to the plateau environment.

[0082] In the present invention, the method for calculating and determining the refrigerant charge amount in the refrigeration assembly and the permafrost cooling device is as follows:

[0083] It is taken as 1 / 3 of the sum of the compression chamber volume of the compressor 9, the internal volume of the condenser 11, and the internal volume of the evaporative cooling tube 17. The compression chamber volume of the compressor 9 and the internal volume of the condenser 11 are determined by consulting the general technical manual of refrigeration equipment and selecting according to the input power. The internal volume of the evaporative cooling tube 17 can be calculated and determined by the inner diameter and length of the copper tube.

[0084] The basic process of preparing cold energy by the refrigeration component in the present invention is as follows:

[0085] ‌1) Compression process‌: After absorbing heat in the evaporation refrigeration tube, the refrigerant vaporizes into low-temperature and low-pressure steam, and then is sucked into the compressor 9 and compressed into high-pressure and high-temperature steam. This process will increase the pressure of the refrigerant and the temperature will also increase. ‌2) Condensation process‌: The high-pressure and high-temperature refrigerant vapor enters the condenser 11, releases heat and condenses into a high-pressure liquid through heat exchange with the cooling medium (air). In this process, the temperature of the refrigerant gradually decreases. ‌3) Throttling expansion process‌: The high-pressure liquid refrigerant passes through the throttle 16, the pressure decreases, and the temperature also decreases. This process will turn the refrigerant into a low-pressure and low-temperature liquid and gas mixture. ‌4) Evaporation process‌: The throttled low-pressure and low-temperature refrigerant exchanges heat with the cooled object (permafrost) in the evaporation refrigeration tube, absorbs heat and vaporizes into a low-temperature and low-pressure steam. This process will reduce the temperature of the permafrost and achieve the purpose of permafrost protection, and the refrigerant will enter the compressor 9 again for the next cycle.

[0086] As a preferred structure, Figure 2 , 3 As shown, a cabinet door 5 capable of being opened and closed is provided on one side of the cabinet 3, an upper support plate 401 and a middle support plate 402 are provided at intervals in the middle position of the cabinet 3, and a lower support plate 403 is provided at the bottom, and the two sides of the upper support plate 401 and the middle support plate 402 are respectively connected to the two side panels 6 adjacent to the cabinet door 5; a cooling output window 7 for the medium conveying assembly to pass through is provided on the side panel 6 opposite to the cabinet door 5; an air distributor 8 for heat dissipation is provided on the upper part of the side panel 6 on both sides of the cabinet door 5; the control assembly is arranged on the middle support plate 402, the high-pressure conversion unit and the high-pressure regulating module are arranged on the upper support plate 401, and the low-pressure refrigeration unit and the low-pressure regulating module are arranged on the lower support plate 403. Wherein, guide rails are provided on the inner walls of the side panels 6 on both sides of the cabinet door 5 to slide with the upper support plate 401, the middle support plate 402 and the two sides of the lower support plate 403. Among them, the cabinet 3 is made of stainless steel plate, and the corrosion resistance of stainless steel is used to resist salt spray erosion and ultraviolet radiation on the plateau, and its high strength is used to cope with extreme weather conditions on the plateau; the cold output window 7 adopts an open-and-close structure to facilitate the connection between the refrigeration unit and the permafrost cold transporter; the air distributor 8 is a shutter with rain and dustproof functions. The refrigeration components and control components are arranged on the upper support plate 401, the middle support plate 402 and the lower support plate 403 respectively. After the sub-units are installed, they are correspondingly inserted into the guide rails on the inner wall of the cabinet, and then the units are connected. Each unit and the cabinet are split structures, with high integration and disassembly efficiency, and easy to assemble, overhaul, and upgrade. At the same time, the high-pressure conversion unit and the low-pressure refrigeration unit are arranged separately, and the cold and heat interference between them is avoided through spatial isolation, which is conducive to maintaining the overall operation effect and energy efficiency level of the refrigeration unit.

[0087] The high-pressure conversion unit and the low-pressure refrigeration unit are connected to form a closed circulation loop, and the connection relationship between the various components is as follows: the outlet of the high-pressure inflow valve 19 is connected to the inlet of the low-pressure gas-liquid separator 25, the gas outlet of the low-pressure gas-liquid separator 25 is connected to the inlet of the regenerator 24, the outlet of the regenerator 24 is connected to the inlet of the compressor 9, the outlet of the compressor 9 is connected to the inlet of the oil separator 10, the outlet of the oil separator 10 is connected to the inlet of the condenser 11, the outlet of the condenser 11 is connected to the inlet of the high-pressure gas-liquid separator 20 of the high-pressure regulating module, the liquid outlet of the high-pressure gas-liquid separator 20 is connected to the inlet of the high-pressure liquid storage tank 13, the outlet of the high-pressure liquid storage tank 13 is connected to the inlet of the flow control valve 14 of the low-pressure module, the outlet of the flow control valve 14 is connected to the inlet of the drying filter 15, the outlet of the drying filter 15 is connected to the inlet of the throttle 16, and the outlet of the throttle 16 is connected to the inlet of the low-pressure outflow valve 18. The pipes used in the above-described connections are all copper pipes with an outer diameter of 6 mm, a wall thickness of 1 mm, and an inner diameter of 4 mm.

[0088] The liquid outlet of the low-pressure gas-liquid separator 25 is connected to the inlet of the low-pressure liquid storage tank 26, and the outlet of the low-pressure liquid storage tank 26 is connected to a joint of the three-way connector II2302 through the liquid reflux pipe 27, and the other two joints of the three-way connector II2302 are respectively connected to the pipeline between the drying filter 15 and the flow control valve 14.

[0089] The gas outlet of the high-pressure gas-liquid separator 20 is connected to the inlet of the high-pressure gas storage tank 21, and the outlet of the high-pressure gas storage tank 21 is connected to a joint of the three-way connector I2301 through the gas reflux pipe 22, and the other two joints of the three-way connector I2301 are respectively connected to the pipeline between the oil separator 10 and the condenser 11.

[0090] The inlet of the evaporative cooling pipe 17 is connected to the outlet of the low-pressure outflow valve 18 , and the outlet of the evaporative cooling pipe 17 is connected to the inlet of the high-pressure inflow valve 19 .

[0091] The joint connection method of each component is as follows: the pipes between the internal components of each unit are connected by welding joints. The pipes between different units are connected by threaded butt sealing joints. The threaded butt sealing joints include positive joints and negative joints, which are easy to install and disassemble.

[0092] With the refrigeration system using the above structure, cabinets, refrigeration units and permafrost coolers can be transported separately and connected and installed on site. The buried and surface components have special heat transfer enhancement, insulation and protection solutions, which improves the transportation convenience of the refrigeration system and its adaptability to application scenarios.

[0093] The present invention also provides a permafrost protection method, which uses the above-mentioned weather-resistant refrigeration system applied to the Qinghai-Tibet Plateau to cool the permafrost, comprising the following steps:

[0094] S1: Permafrost scenario survey. Based on the deformation and damage scenarios of railway and highway embankments 33 caused by the degradation and thawing of permafrost foundations 34, the permafrost range that needs to be cooled and protected is delineated. Based on the permafrost temperature and warming trend, combined with the heat storage theory, the cooling capacity required per unit area of ​​permafrost within the protection range is calculated. This is a prior art and will not be elaborated here.

[0095] S2: Design and prepare the refrigeration system. The cold diffusion coverage radius of the permafrost cooling device 2 of each refrigeration system is 3.0 meters. Combined with the permafrost protection area, the required number of refrigeration systems is calculated, and the on-site layout plan of the permafrost cooling device 2 is designed. Combined with the required cooling capacity per unit area of ​​permafrost determined in step S1, multiplied by the circular area with a cold diffusion coverage radius of 3.0m, the refrigeration capacity of a single refrigeration system is calculated, and the refrigeration unit is selected, mainly including key functional components such as compressor 9, condenser 11, high-pressure liquid storage tank 13, evaporative refrigeration pipe 17, and key performance improvement components such as high-pressure gas storage tank 21 and low-pressure liquid storage tank 26. In addition, the overall height of the evaporative refrigeration pipe 17 should be equal to the permafrost protection depth. According to the selection results, the unitized production and assembly integration of the refrigeration unit 1 are carried out.

[0096] The permafrost cooling device 2 is designed and produced, and the height of the stainless steel sleeve 28 is designed to be equal to the overall height of the evaporative cooling tube 17 in step S2. The stainless steel sleeve 28 and the end protection assembly are produced and manufactured. According to the on-site layout plan of the permafrost cooling device 2, drilling or grooving operations are performed to place the stainless steel sleeve 28.

[0097] S3: Install and commission the refrigeration system.

[0098] When there is no other work at the work site and the site is cleaned, first insert the evaporative cooling tube 17 into the stainless steel casing 28. Then, install and fix the cabinet 3 with the refrigeration unit 1 near the stainless steel casing 28. After that, connect and debug the evaporative cooling tube 17 and the refrigeration unit 1.

[0099] The connection and debugging steps between the evaporative cooling pipe 17 and the refrigeration unit 1 are as follows: 1) Connect the low-pressure outflow valve 18 to the inlet of the evaporative cooling pipe 17, and then slightly unscrew the low-pressure outflow valve 18 until there is a slight airflow at the outlet of the evaporative cooling pipe 17. The purpose of this step is to exhaust the air inside the evaporative cooling pipe 17; 2) Under the premise of maintaining a slight airflow, connect the high-pressure inflow valve 19 to the outlet of the evaporative cooling pipe 17; 3) After the connection is completed, slightly unscrew the high-pressure inflow valve 19 to check the sealing of all threaded butt sealing joints; 4) Completely unscrew the low-pressure outflow valve 18 and the high-pressure inflow valve 19, start the refrigeration system for trial operation, and until the operating status is normal.

[0100] Finally, the permafrost cooler 2 is filled with heat transfer fluid and insulated. After the refrigeration unit 1 is debugged normally, the finishing work is carried out. First, the heat transfer fluid is poured into the stainless steel casing 28 to complete the installation of the heat transfer increase component. Secondly, the flange base 29 and the flange buckle cover 30 are installed on the top of the stainless steel casing 28, and polyurethane foam glue is injected into the flange buckle cover 30 to complete the installation of the end protection component. Then, the copper pipe connecting pipeline between the cabinet 3 of the refrigeration unit 1 and the evaporative cooling pipe 17 is wrapped with an insulation pipe, and the outer wall of the insulation pipe is wrapped with a rubber-plastic tie, and then embedded in the PVC casing to complete the installation of the insulation connection component.

[0101] S4: Dynamically control the refrigeration system.

[0102] The setting requirements for the normal operation state of the refrigeration system are as follows: the normal temperature range of the compression chamber and the motor of the compressor 9 is 60-90°C, and the upper limit is 110°C. The normal pressure range of the condenser 11 is 2.2-2.6MPa, and the allowable pressure drop range is 0.10-0.25MPa. The normal pressure range of the evaporative refrigeration pipe 17 is 0.6-0.8MPa, and the allowable pressure drop range is generally between 0.05-0.15MPa.

[0103] If the compressor 9 is unloaded (the refrigerant circulation flow rate is too small), the compression chamber will be overheated. If the compressor 9 is overloaded (the refrigerant circulation flow rate is too large), the motor will be overheated.

[0104] If the refrigerant circulation flow rate is too large, the absolute value of the pressure inside the condenser 11 will be too low. If the refrigerant liquefaction rate inside the condenser 11 is too low, the pressure drop will be too small.

[0105] If the refrigerant circulation flow rate is too large, the absolute value of the pressure inside the evaporative refrigeration tube 17 will be too large. If the refrigerant gasification rate inside the evaporative refrigeration tube 17 is too low, the pressure drop will be too large.

[0106] The operation control method of the refrigeration system is as follows:

[0107] (1) Refrigeration system start-up: A first refrigeration temperature is set on the actuator 32, and the first refrigeration temperature is set to be -20°C lower than the average temperature of permafrost, and the refrigeration system is started.

[0108] (2) Setting of the normal operation mode of the refrigeration system. The normal state execution scheme of the actuator 32 is that the opening degree of the flow control valve 14 is 50%, and the inlets of the three-way connector I 2301 and the three-way connector II 2302 are closed;

[0109] (3) Adaptive dynamic adjustment of refrigeration system.

[0110] The controller 31 controls the compression chamber temperature sensor of the compressor 9 to monitor once at the 0th, 10th, 20th, 30th, 40th, and 50th minute of each hour, controls the motor temperature sensor of the compressor 9 to monitor once at the 5th, 15th, 25th, 35th, 45th, and 55th minute of each hour, and controls the pressure sensor to monitor once every 10 minutes. The controller 31 determines the operating status of the refrigeration system and executes the following commands:

[0111] 1) When the monitored temperature of the compression chamber of the compressor 9 exceeds the set range, when the monitored temperature is 90-95°C, the opening of the flow control valve 14 is set to 60%; when the monitored temperature is 95-100°C, the opening of the flow control valve 14 is set to 70%; when the monitored temperature is 100-105°C, the opening of the flow control valve 14 is set to 80%; when the monitored temperature is 105-110°C, the opening of the flow control valve 14 is set to 90%; after the monitored temperature exceeds 110°C, the compressor stops for 10 minutes;

[0112] 2) When the monitored temperature of the motor of the compressor 9 exceeds the set range, the opening of the flow control valve 14 is set to the current value - 5%; when the monitored temperature is 95-100°C, the opening of the flow control valve 14 is set to the current value - 10%; when the monitored temperature is 100-105°C, the opening of the flow control valve 14 is set to the current value - 15%; when the monitored temperature is 105-110°C, the opening of the flow control valve 14 is set to the current value - 20%; after the monitored temperature exceeds 110°C, the compressor stops for 10 minutes;

[0113] 3) When the pressure drop value inside the condenser 11 exceeds the set range, the inlet of the three-way connector I2301 is opened, otherwise it is closed;

[0114] 4) When the pressure drop value inside the evaporative cooling tube 17 exceeds the set range, the inlet of the three-way connector II 2302 is opened, otherwise it is closed.

[0115] (4) Output temperature adjustment of the refrigeration system: When the permafrost temperature monitoring shows that the cold diffusion and cooling range between adjacent permafrost coolers 2 have overlapped (i.e., the cold diffusion range overlaps), the second refrigeration temperature is reset to be -10°C lower than the average permafrost temperature.

[0116] The reason for setting the first refrigeration temperature and the second refrigeration temperature is that the cooling effect of the permafrost refrigeration device 2 is affected by two factors: the cooling temperature and the cooling capacity. These two factors are controlled by the refrigeration unit 1, and the two are negatively correlated. This is the prior art. The cooling temperature determines the diffusion rate of the cold inside the permafrost, that is, the thermal influence range of the permafrost refrigeration device 2; the permafrost cooling capacity determines the cooling range of the permafrost within the thermal influence range. In actual application, it is advisable to first set a lower output temperature (larger output temperature absolute value) to rapidly expand the thermal influence range of the permafrost refrigeration device; then increase the output temperature (smaller output temperature absolute value), increase the cooling capacity, so that the permafrost within the thermal influence range has a sufficient cooling range, and improve the permafrost protection effect.

[0117] (5) The refrigeration system continues to perform adaptive dynamic adjustment until the permafrost cools to the target temperature.

[0118] In summary, the refrigeration system provided by the present invention has the technical effects of convenient transportation and installation, good scene adaptability, reliable operation and intelligence. The present invention provides an operation control method of a refrigeration system, with an embedded device dynamic operation control logic, and has an adaptive intelligent adjustment function for plateau climate and permafrost geological environment. The present invention can reasonably design the number of refrigeration systems, on-site layout plans and component selection according to the actual protection needs of permafrost, to ensure the balance of refrigeration supply and demand and the protection effect of permafrost.

[0119] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau, characterized in that: The refrigeration system includes a plurality of refrigeration units and a plurality of permafrost cooling devices, wherein the refrigeration unit is arranged on the ground, and the permafrost cooling device is arranged in the permafrost underground; the permafrost cooling device is connected to the refrigeration unit through a medium conveying component, and after the refrigeration unit cools the refrigerant, the refrigerant is conveyed to the permafrost cooling device through the medium conveying component, and the refrigerant in the permafrost cooling device exchanges heat with the permafrost to reduce the temperature of the permafrost; The refrigeration unit includes a cabinet and a refrigeration component and a control component inside the cabinet. The refrigeration component includes a high-pressure conversion unit, a low-pressure refrigeration unit and a plateau environment performance improvement component. The plateau environment performance improvement component includes a high-pressure regulation module and a low-pressure regulation module. The high-pressure regulation module is connected to the high-pressure conversion unit, and the low-pressure regulation module is connected to the low-pressure refrigeration unit; the high-pressure conversion unit and the low-pressure refrigeration unit are respectively connected to the permafrost cooling device through a medium conveying component; the control component is used to control the operation of the refrigeration component and monitor the temperature and pressure of the refrigeration component and the inlet and outlet pressures of the permafrost cooling device; The high-pressure conversion unit includes a compressor, an oil separator, a condenser, a fan and a high-pressure liquid storage tank. The high-pressure regulating module includes a high-pressure gas-liquid separator, a high-pressure gas storage tank, a three-way connector I and a regenerator. The outlet of the compressor is connected to the oil separator, and the outlet of the oil separator is connected to the inlet of the condenser through the three-way connector I. The outlet of the condenser is connected to the inlet of the high-pressure gas-liquid separator, and the liquid outlet of the high-pressure gas-liquid separator is connected to the inlet of the high-pressure liquid storage tank. The outlet of the high-pressure liquid storage tank is connected to the inlet of the flow control valve of the low-pressure refrigeration unit; the gas outlet of the high-pressure gas-liquid separator is connected to the inlet of the high-pressure gas storage tank, and the outlet of the high-pressure gas storage tank is connected to a joint of the three-way connector I through a gas return pipe, and the other two joints of the three-way connector I are respectively connected to the pipeline between the oil separator and the condenser; the gas outlet of the low-pressure gas-liquid separator of the low-pressure regulating module is connected to the inlet of the regenerator, and the outlet of the regenerator is connected to the inlet of the compressor; the regenerator and the fan are respectively arranged on both sides of the condenser, and the regenerator is used to absorb the heat released by the condenser; The low-pressure refrigeration unit includes a flow control valve, a filter drier and a throttle, the low-pressure regulating module includes a low-pressure gas-liquid separator, a low-pressure liquid storage tank, a liquid return pipe and a three-way connector II, the outlet of the flow control valve is connected to the inlet of the filter drier through the three-way connector II, the outlet of the filter drier is connected to the inlet of the throttle, and the outlet of the throttle is connected to the inlet of the low-pressure outflow valve; the inlet of the low-pressure gas-liquid separator is connected to the refrigerant outlet of the permafrost cooling device through the high-pressure inflow valve of the control component, the liquid outlet of the low-pressure gas-liquid separator is connected to the inlet of the low-pressure liquid storage tank, the outlet of the low-pressure liquid storage tank is connected to a joint of the three-way connector II through the liquid return pipe, and the other two joints of the three-way connector II are respectively connected to the pipeline between the filter drier and the flow control valve; The permafrost cooling device includes a cold storage and heat transfer enhancement component and an end protection component. The cold storage and heat transfer enhancement component includes a sleeve and an evaporative cooling tube inside the sleeve. The sleeve is arranged in the permafrost. The sleeve is a hollow tube body with a sealed end. The evaporative cooling tube is spirally arranged inside the sleeve. A heat transfer fluid is filled between the evaporative cooling tube and the sleeve. The refrigerant in the evaporative cooling tube exchanges heat with the permafrost through the heat transfer fluid. The open end of the sleeve is connected to the end protection component, and the medium conveying pipe of the medium conveying component passes through the end protection component and is connected to the evaporative cooling tube.

2. A weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau according to claim 1, characterized in that: The control component includes a low-pressure outflow valve, a high-pressure inflow valve, a temperature sensor, a pressure sensor, a controller and an actuator. The low-pressure outflow valve and the high-pressure inflow valve are arranged in parallel in the middle of the cabinet. The inlet of the low-pressure outflow valve is connected to the refrigerant outlet of the low-pressure refrigeration unit, the outlet of the low-pressure outflow valve is connected to the refrigerant inlet of the permafrost cooling device, the inlet of the high-pressure inflow valve is connected to the refrigerant outlet of the permafrost cooling device, and the outlet of the high-pressure inflow valve is connected to the inlet of the low-pressure gas-liquid separator of the low-pressure refrigeration unit; the temperature sensor and the pressure sensor are both arranged in the refrigeration component, and the controller and the actuator are correspondingly arranged in the middle of the inner side of the cabinet; the low-pressure outflow valve, the high-pressure inflow valve, the temperature sensor, the pressure sensor, the refrigeration component and the actuator are all connected to the controller, and the actuator is used to execute the control instructions of the controller to realize human-computer interaction.

3. The weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau according to claim 1, characterized in that: The end protection assembly includes a flange base and a flange buckle cover. The flange base is fixedly mounted on the upper end of the sleeve. The flange buckle cover is a hollow shell. The flange buckle cover is connected to the flange base on all sides by bolts. The inner cavity formed by the flange buckle cover and the flange base is filled with polyurethane foam glue.

4. The weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau according to claim 2, characterized in that: A cabinet door that can be opened and closed is provided on one side of the cabinet, an upper support plate and a middle support plate are provided at intervals in the middle position of the interior of the cabinet, and a lower support plate is provided at the bottom, and the two sides of the upper support plate and the middle support plate are respectively connected to the two side panels adjacent to the cabinet door; a cooling output window for the medium conveying component to pass through is provided on the side panel opposite to the cabinet door; and air distributors for heat dissipation are provided on the upper parts of the side panels on both sides of the cabinet door; The control assembly is arranged on the middle support plate, the high-pressure conversion unit and the high-pressure regulating module are arranged on the upper support plate, and the low-pressure refrigeration unit and the low-pressure regulating module are arranged on the lower support plate.

5. The weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau according to claim 4, characterized in that: Guide rails which are slidably matched with the upper support plate, the middle support plate and the lower support plate are respectively arranged on the inner walls of the side plates on both sides of the cabinet door.

6. A method for protecting permafrost, characterized in that: The permafrost is cooled by using the weather-resistant refrigeration system for use in the Qinghai-Tibet Plateau as claimed in any one of claims 2 to 5, comprising the following steps: S1: Permafrost scenario investigation; S2: Design and prepare refrigeration system; S3: Install and debug the refrigeration system; S4: Dynamically control the refrigeration system. The operation control method of the refrigeration system is as follows: (1) Setting the first refrigeration temperature on the actuator, which is set to -20°C lower than the average temperature of permafrost, and starting the refrigeration system; (2) Normal operation mode setting of the refrigeration system: the flow control valve in the low-pressure refrigeration unit is opened to 50%, and the inlets of the three-way connector I and the three-way connector II are closed; (3) Adaptive dynamic adjustment of the refrigeration system: The controller controls the monitoring frequency of the compression chamber temperature of the compressor and the motor temperature, and controls the monitoring frequency of the inlet and outlet pressures of the condenser, the inlet and outlet pressures of the high-pressure inlet valve, and the low-pressure outflow valve. The controller determines the operating status of the refrigeration system. (4) Adjusting the output temperature of the refrigeration system: When the permafrost temperature monitoring shows that the cooling diffusion and the cooling range between adjacent permafrost coolers have been circled, reset the second refrigeration temperature to -10°C lower than the average permafrost temperature; (5) The refrigeration system continues to perform adaptive dynamic adjustment until the permafrost is cooled to the target temperature.

7. The permafrost protection method according to claim 6, characterized in that: In step (3), the adaptive dynamic adjustment method of the refrigeration system is as follows: The controller controls the compressor compression chamber temperature to be monitored once at 0, 10, 20, 30, 40, and 50 minutes per hour, the compressor motor temperature to be monitored once at 5, 15, 25, 35, 45, and 55 minutes per hour, and the control pressure to be monitored once every 10 minutes. The controller determines the operating status of the refrigeration system and executes the following commands: 1) When the monitoring temperature of the compression chamber of the compressor exceeds the set range, when the monitoring temperature is 90-95℃, the flow control valve opening is set to 60%; when the monitoring temperature is 95-100℃, the flow control valve opening is set to 70%; when the monitoring temperature is 100-105℃, the flow control valve opening is set to 80%; when the monitoring temperature is 105-110℃, the flow control valve opening is set to 90%; after the monitoring temperature exceeds 110℃, the compressor will stop for 10 minutes; 2) When the monitored temperature of the compressor motor exceeds the set range, the flow control valve opening is set to the current value - 5%; when the monitored temperature is 95-100℃, the flow control valve opening is set to the current value - 10%; when the monitored temperature is 100-105℃, the flow control valve opening is set to the current value - 15%; when the monitored temperature is 105-110℃, the flow control valve opening is set to the current value - 20%; after the monitored temperature exceeds 110℃, the compressor will stop for 10 minutes; 3) When the pressure drop value inside the condenser exceeds the set range, open the inlet of the three-way connector I, otherwise close it; 4) When the pressure drop inside the evaporative refrigeration pipe exceeds the set range, open the inlet of the three-way connector II, otherwise close it.

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