Carbon dioxide water-cooling cascade system

Abstract

The utility model discloses a carbon dioxide water-cooling cascade system which comprises a carbon dioxide circulation loop and a water-cooling cascade circulation loop, the carbon dioxide circulation loop carries out compression refrigeration circulation and comprises a condenser, and a carbon dioxide heat exchange pipeline and a water-cooling heat exchange pipeline are arranged in the condenser. The carbon dioxide heat exchange pipeline is connected with a carbon dioxide circulation loop, and the water-cooling heat exchange pipeline is connected with a water-cooling cascade circulation loop; the water-cooling cascade circulation loop comprises a water chilling unit, a refrigeration air cooler, a cooling tower, ice storage equipment and a water pump. The utility model has the advantages of energy conservation, carbon reduction, greenness, environmental protection, insensitivity to system pressure, small system pressure fluctuation during temperature reduction, and stability.

Description

TECHNICAL FIELD

[0001] The utility model relates to refrigeration and heating technical field, concretely is a kind of carbon dioxide water cooling cascade system. BACKGROUND

[0002] Carbon dioxide is a kind of natural refrigerant, green environmental protection, leakage or not recycling cannot pollute environment;With good thermodynamic characteristics, high thermal conductivity coefficient;Unit volume refrigerating capacity is high, equipment size can be significantly reduced, save material;Carbon dioxide high temperature cooling and cold water temperature matching degree are high, greatly improve the heat exchange efficiency of condensing evaporator;Using water chiller can replace carbon dioxide and freon cascade system, reduce the filling amount of freon.

[0003] Therefore, it is necessary to design a kind of carbon dioxide water cooling cascade system, replace the freon cascade system with greater influence on environment. UTILITY MODEL CONTENT

[0004] The utility model aims at solving the environmental protection problem of carbon dioxide freon cascade system, provides a kind of energy-saving, carbon reduction, more green environmental protection, not sensitive to system pressure, system pressure fluctuation is small when cooling, more stable carbon dioxide water cooling cascade system.

[0005] To achieve the above object, the utility model provides the following technical scheme:

[0006] The application discloses a carbon dioxide water cooling cascade system, which comprises a carbon dioxide circulation loop and a water cooling cascade circulation loop.

[0007] Compared with the traditional fluorine system, the carbon dioxide cascade system can reduce the fluorine usage by more than 90%; the fluorine refrigeration pipeline of the carbon dioxide water cooling cascade system is shorter, the evaporative condenser is cancelled, compared with the carbon dioxide and fluorine cascade system, the carbon dioxide water cooling cascade system can further reduce the charging amount by more than 50%, and is more green and environmentally friendly; the specific heat of the chilled water is large, the system pressure is not sensitive, the system pressure fluctuation is small during cooling, compared with the carbon dioxide refrigeration mode for the fresh-keeping warehouse and the through hall, the water cooling system is more stable; the design pressure of the high-pressure side of the carbon dioxide water cooling cascade system is 52 bar, and the design pressure of the low-pressure side is 39 bar.

[0008] As a preferred scheme of the application, the carbon dioxide circulation loop comprises a carbon dioxide compressor set, an oil separator, a condenser and a carbon dioxide heat exchange pipeline, a carbon dioxide liquid storage device, a carbon dioxide refrigeration pump and a heat regenerator which are sequentially connected in pipeline communication.

[0009] As the preferred scheme of the utility model, the carbon dioxide circulation loop, the carbon dioxide refrigeration pump output end is connected through the first straight through stop valve pipeline with the regenerator first inlet, and is connected with the low temperature cold air blower inlet through the second straight through stop valve pipeline, the regenerator first outlet is connected with the connecting pipeline between the second straight through stop valve and the low temperature cold air blower inlet, the connecting pipeline is equipped with electronic expansion valve, the low temperature cold air blower outlet is connected with the regenerator second inlet through the first electromagnetic valve, third straight through stop valve pipeline, the regenerator second outlet pipeline is connected with the carbon dioxide compressor unit, when the compression refrigeration cycle is started, the carbon dioxide circulation loop, carbon dioxide compressor unit, condenser, carbon dioxide refrigeration pump, low temperature cold air blower run, first straight through stop valve, second straight through stop valve, electronic expansion valve, first electromagnetic valve, third straight through stop valve open.

[0010] As the preferred scheme of the utility model, when the water-cooled cascade circulation loop carries out high-temperature stage compression cycle, the first regulating control valve is closed with the connecting port of the ice storage equipment, the second regulating control valve connecting port is opened, the water-cooled electromagnetic valve is opened, the first water pump circulates the chilled water circulating unit and exports the chilled water to the refrigeration cold air blower, and the chilled water is transported to the condenser water-cooled heat exchange pipeline through the pipeline after absorbing heat and returns to the chilled water circulating unit cooling, and the second water pump circulates the cooling water circulating unit and exports the cooling water to the cooling tower and cools after cooling and returns to the cooling water circulating unit to absorb heat.

[0011] As the preferred scheme of the utility model, when the water-cooled cascade circulation loop carries out refrigeration cold air blower alone cooling, the first regulating control valve is closed with the connecting port of the ice storage equipment, the second regulating control valve is closed with the connecting port of the condenser water-cooled heat exchange pipeline, the water-cooled electromagnetic valve is opened, and the first water pump circulates the chilled water circulating unit and exports the chilled water to the refrigeration cold air blower and absorbs heat after being transported to the refrigeration cold air blower and returns to the chilled water circulating unit cooling.

[0012] As the preferred scheme of the utility model, when the water-cooled cascade circulation loop carries out condenser water-cooled heat exchange pipeline alone condensation, the first regulating control valve is closed with the connecting port of the ice storage equipment, the second regulating control valve is closed with the connecting port of the refrigeration cold air blower, the first water pump circulates the chilled water circulating unit and exports the chilled water to the condenser water-cooled heat exchange pipeline and absorbs heat after being transported to the condenser water-cooled heat exchange pipeline and returns to the chilled water circulating unit cooling.

[0013] As the preferred scheme of the utility model, the first regulating control valve is closed with the connecting port of the ice storage equipment, and the second regulating control valve connecting port is opened according to requirements, the refrigerated water circulating unit is opened, and the first water pump circulates the cold water in the refrigerated water circulating unit to the refrigerated air cooler for cooling, the condenser water cooling heat exchange pipeline for condensing and then returns to the refrigerated water circulating unit.

[0014] As the preferred scheme of the utility model, the first regulating control valve is closed with the connecting port of the ice storage equipment, and the second regulating control valve connecting port is opened according to requirements, the refrigerated water circulating unit is opened, and the first water pump circulates the cold water in the refrigerated water circulating unit to the refrigerated air cooler for cooling, the condenser water cooling heat exchange pipeline for condensing and then returns to the refrigerated water circulating unit.

[0015] As the preferred scheme of the utility model, the first regulating control valve is closed with the connecting port of the ice storage equipment, and the second regulating control valve connecting port is opened according to requirements, the refrigerated water circulating unit is opened, and the first water pump circulates the cold water in the refrigerated water circulating unit to the refrigerated air cooler for cooling, the condenser water cooling heat exchange pipeline for condensing and then returns to the refrigerated water circulating unit.

[0016] As the preferred scheme of the utility model, the first regulating control valve is closed with the connecting port of the ice storage equipment, and the second regulating control valve connecting port is opened according to requirements, the refrigerated water circulating unit is opened, and the first water pump circulates the cold water in the refrigerated water circulating unit to the refrigerated air cooler for cooling, the condenser water cooling heat exchange pipeline for condensing and then returns to the refrigerated water circulating unit.

[0017] In the scheme, the carbon dioxide water cooling cascade system greatly reduces the charge amount of freon compared with the carbon dioxide and freon cascade system, and the charge amount of freon is further reduced by adopting the fluorine micro-charge technology in the internal circulation of the water chilling unit, and the charge amount of freon is reduced again. The carbon dioxide water cooling cascade system has the advantages of small noise, high stability, energy saving and environmental protection, safety and reliability, low maintenance cost and the like without affecting the refrigeration effect. The traditional carbon dioxide cascade system (carbon dioxide and freon cascade or ammonia cascade) is often affected by the load, load reduction and overheating degree adjustment of the fluorine or ammonia system. Compared with the traditional carbon dioxide cascade system, the system runs more stably and is easier to cooperate.

[0018] The carbon dioxide water cooling cascade system has the advantages of comfortable air supply, green environmental protection, stable execution, less investment, easy maintenance, small temperature difference between supply air and return air compared with the freon direct expansion system, and high safety factor and good reliability compared with the carbon dioxide cooling system.

[0019] The carbon dioxide water cooling cascade system is provided with an ice storage system, and can realize peak shaving, reduces the power supply pressure of a power station, and reduces the electricity cost of a user. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A pipeline connecting structure of the utility model.

[0021] In the drawing: 1, carbon dioxide compressor unit 2, oil separator 3, condenser

[0022] 4, carbon dioxide storage liquid tank 5, electronic expansion valve 6, low-temperature cold air machine

[0023] 7, heat regenerator 8, cold water unit 9, refrigeration cold air machine 10, cooling tower

[0024] 11, carbon dioxide refrigeration pump 13, second straight-through stop valve 14, first electromagnetic valve

[0025] 15, third straight-through stop valve 16, first straight-through stop valve 20, water-cooled electromagnetic valve

[0026] 21, second water pump 22, first water pump 23, first regulating control valve

[0027] 24, ice storage equipment 25, temperature sensor 26, second regulating control valve

[0028] 27, first bifurcated pipeline 28, second bifurcated pipeline 31, carbon dioxide heat exchange pipeline

[0029] 32, water-cooled heat exchange pipeline 81, refrigerated water circulating unit 82, cooling water circulating unit. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments.

[0031] Reference Figure 1 ,

[0032] The application discloses a carbon dioxide water cooling cascade system, which comprises a carbon dioxide circulation loop and a water cooling cascade circulation loop, wherein the carbon dioxide circulation loop performs a compression refrigeration cycle and comprises a condenser 3, the condenser 3 is provided with a carbon dioxide heat exchange pipeline 31 and a water cooling heat exchange pipeline 32, the carbon dioxide heat exchange pipeline 31 is connected with the carbon dioxide circulation loop, and the water cooling heat exchange pipeline 32 is connected with the water cooling cascade circulation loop; the water cooling cascade circulation loop comprises a water cooling unit 8, a refrigeration air cooler 9, a cooling tower 10, an ice storage device 24 and a water pump, the water cooling unit 8 comprises a chilled water circulation unit 81 and a cooling water circulation unit 82, the water inlet and the water outlet of the cooling water circulation unit 82 are respectively communicated with the pipeline of the cooling tower 10 to form a cooling water circulation pipeline, and the cooling water circulation pipeline is provided with a second water pump 21; the chilled water circulation unit 81, the ice storage device 24, the refrigeration air cooler 9 and the water cooling heat exchange pipeline 32 are communicated to form a chilled water circulation pipeline, the water outlet of the chilled water circulation unit 81 is communicated with a first regulating control valve 23 through a pipeline, the first regulating control valve 23 is communicated with the water inlet of the ice storage device 24 through a pipeline, the first regulating control valve 23 and the water outlet of the ice storage device 24 are communicated with a same valve port of a second regulating control valve 26 through a first bifurcated pipeline 27, the first bifurcated pipeline 27 is provided with a temperature sensor 25, the temperature sensor 25 is signal-connected with the first regulating control valve 23, the second regulating control valve 26 is communicated with the water inlet of the water cooling heat exchange pipeline 32 of the condenser 3 through a pipeline, the second regulating control valve 26 is also communicated with the water outlet of the refrigeration air cooler 9 through a water cooling electromagnetic valve 20, the water inlet of the refrigeration air cooler 9 and the water inlet of the chilled water circulation unit 81 are communicated with the water outlet of the water cooling heat exchange pipeline 32 of the condenser 3 through a second bifurcated pipeline 28, and the chilled water circulation pipeline is provided with a first water pump 22; the first regulating control valve 23 is provided with three valve ports A, B and C, and the second regulating control valve 26 is provided with three valve ports E, F and G.

[0033] The carbon dioxide circulation loop comprises a carbon dioxide compressor unit 1, an oil separator 2, the condenser 3 and the carbon dioxide heat exchange pipeline 31, a carbon dioxide liquid storage device 4, a carbon dioxide refrigeration pump 11 and a regenerator 7 which are communicated in sequence, and the regenerator 7 is connected with a low-temperature air cooler 6 and the carbon dioxide compressor unit 1.

[0034] In the carbon dioxide circulation loop, the output end of the carbon dioxide refrigeration pump 11 is connected to the first inlet of the regenerator 7 through the first straight-through stop valve 16, and to the inlet of the low-temperature cold air fan 6 through the second straight-through stop valve 13. The first outlet of the regenerator 7 is connected to the connecting pipeline between the second straight-through stop valve 13 and the inlet of the low-temperature cold air fan 6, and an electronic expansion valve 5 is arranged on the connecting pipeline. The outlet of the low-temperature cold air fan 6 is connected to the second inlet of the regenerator 7 through the first electromagnetic valve 14 and the third straight-through stop valve 15, and the second outlet of the regenerator 7 is connected to the carbon dioxide compressor set 1. When the compression refrigeration cycle is started, the carbon dioxide compressor set 1, the condenser 3, the carbon dioxide refrigeration pump 11, and the low-temperature cold air fan 6 operate in the carbon dioxide circulation loop, and the first straight-through stop valve 16, the second straight-through stop valve 13, the electronic expansion valve 5, the first electromagnetic valve 14, and the third straight-through stop valve 15 are opened.

[0035] When the high-temperature stage compression cycle is performed in the water-cooled cascade circulation loop, the first adjusting control valve 23 is closed to the connecting port of the ice storage device 24, the connecting ports of the second adjusting control valve 26 are all opened, and the water-cooled electromagnetic valve 20 is opened. The first water pump 22 circulates the chilled water discharged from the chilled water circulation unit 81 to the refrigeration cold air fan 9 and the condenser 3 water-cooled heat exchange pipeline 32 to absorb heat and then returns to the chilled water circulation unit 81 for cooling. The second water pump 21 circulates the cooling water in the cooling water circulation unit 82 to the cooling tower 10 for cooling and then returns to the cooling water circulation unit 82 to absorb heat.

[0036] When the refrigeration cold air fan 9 is cooled alone in the water-cooled cascade circulation loop, the first adjusting control valve 23 is closed to the connecting port of the ice storage device 24, the second adjusting control valve 26 is closed to the connecting port of the condenser 3 water-cooled heat exchange pipeline 32, and the water-cooled electromagnetic valve 20 is opened. The first water pump 22 circulates the chilled water discharged from the chilled water circulation unit 81 to the refrigeration cold air fan 9 to absorb heat and then returns to the chilled water circulation unit 81 for cooling.

[0037] When the condenser 3 water-cooled heat exchange pipeline 32 is condensed alone in the water-cooled cascade circulation loop, the first adjusting control valve 23 is closed to the connecting port of the ice storage device 24, the second adjusting control valve 26 is closed to the connecting port of the refrigeration cold air fan 9, and the first water pump 22 circulates the chilled water discharged from the chilled water circulation unit 81 to the condenser 3 water-cooled heat exchange pipeline 32 to absorb heat and then returns to the chilled water circulation unit 81 for cooling.

[0038] When the ice storage and the refrigeration cold air fan 9 cooling and the condenser 3 water-cooled heat exchange pipeline 32 condensing are performed simultaneously in the water-cooled cascade circulation loop, the first adjusting control valve 23 is closed to the connecting port of the second adjusting control valve 26, the connecting ports of the second adjusting control valve are opened according to requirements, the water-cooled electromagnetic valve is opened, and the first water pump circulates the chilled water discharged from the chilled water circulation unit to the ice storage device, the refrigeration cold air fan, and the condenser water-cooled heat exchange pipeline to absorb heat and then returns to the chilled water circulation unit for cooling.

[0039] When the water-cooled cascade circulation loop is used for ice-melting cooling alone, the first regulating control valve 23 and the second regulating control valve 26 are opened according to the requirement, the chilled water circulation unit 81 is not started, and the first water pump 22 sends the chilled water in the chilled water circulation unit 81 to the ice storage device 24 through a pipeline for ice-melting and cooling, and then to the refrigeration air cooler 9 for cooling, to the water-cooled heat exchange pipeline 32 of the condenser 3 for condensing, and back to the chilled water circulation unit 81.

[0040] When the water-cooled cascade circulation loop is used for ice-melting cooling, the first regulating control valve 23 and the second regulating control valve 26 are opened according to the requirement, the chilled water circulation unit 81 is started, and the first water pump 22 sends the chilled water in the chilled water circulation unit 81 to the ice storage device 24 through a pipeline for ice-melting and cooling, and then to the refrigeration air cooler 9 for cooling, to the water-cooled heat exchange pipeline 32 of the condenser 3 for condensing, and back to the chilled water circulation unit 81.

[0041] When the water-cooled cascade circulation loop is used for regular refrigeration cycle, the first regulating control valve 23 is closed, the second regulating control valve 26 is opened according to the requirement, the chilled water circulation unit 81 is started, and the first water pump 22 sends the chilled water in the chilled water circulation unit 81 to the refrigeration air cooler 9 for cooling, to the water-cooled heat exchange pipeline 32 of the condenser 3 for condensing, and back to the chilled water circulation unit 81.

[0042] Specific use process:

[0043] In the carbon dioxide water-cooled cascade system, the design pressure of the high-pressure side of the carbon dioxide is 52 bar, and the design pressure of the low-pressure side is 39 bar.

[0044] The low-temperature stage compression cycle of the carbon dioxide water-cooled cascade system is as follows: high-temperature and high-pressure carbon dioxide gas is discharged from the carbon dioxide compressor unit 1 to the oil separator 2 for gas-oil separation, and then is condensed at the condenser 3 through a pipeline to exchange heat with water to obtain supercooled high-pressure liquid; the low-temperature and high-pressure carbon dioxide liquid is pumped out from the carbon dioxide storage tank 4 by the carbon dioxide refrigeration pump 11; the low-temperature and low-pressure two-phase carbon dioxide is obtained by throttling and expansion through the straight-through stop valve 13 and the pipeline through the electronic expansion valve 5; the low-temperature and low-pressure carbon dioxide gas is obtained by heat exchange with the environment in the low-temperature air cooler 6; the low-temperature and low-pressure carbon dioxide gas is exchanged with the environment in the heat regenerator 7 through the electromagnetic valve 14 and the straight-through stop valve 15; and finally, the low-temperature and low-pressure carbon dioxide gas is returned to the carbon dioxide compressor unit 1 through a pipeline to complete a single compression and refrigeration cycle.

[0045] The high-temperature stage compression cycle of the water-cooled CO2 cascade system is as follows: the chilled water of -5-5°C discharged by the chilled water circulation unit 81 is delivered by the first water pump 22 to the refrigerated air cooler 9 through a pipeline to exchange heat with the environment to reduce the temperature of the refrigerated storage to 0-4°C; the chilled water is delivered to the condenser 3 through a pipeline to exchange heat with the high-temperature and high-pressure CO2 gas of the low-temperature stage compression cycle to obtain chilled water of about 5°C; and the chilled water is returned to the chilled water circulation unit 81 through a pipeline to be cooled.

[0046] When the water-cooled cascade cycle loop is used to cool the refrigerated storage alone, the chilled water circulation unit 81 is operated, the chilled water of -5-5°C discharged by the chilled water circulation unit 81 is delivered by the first water pump 22 to the refrigerated air cooler 9 through the AC interface of the first regulating control valve 23 and the EG interface of the second regulating control valve 26, the water-cooled electromagnetic valve 20, the refrigerated air cooler 9 and a pipeline, and finally returned to the chilled water circulation unit 81.

[0047] When the water-cooled cascade cycle loop is used to condense the condenser water-cooled heat exchange pipeline alone, the chilled water circulation unit 81 is opened, the flow direction of the first regulating control valve 23 is A-C, the chilled water of -5-5°C discharged by the chilled water circulation unit 81 is delivered by the first water pump 22 to the condenser 3 through the AC interface of the first regulating control valve 23 and the EF interface of the second regulating control valve 26, and finally returned to the chilled water circulation unit 81.

[0048] When the water-cooled cascade cycle loop is used to store ice and cool the refrigerated air cooler 9 and condense the condenser 3 water-cooled heat exchange pipeline 32, the chilled water circulation unit 81 is operated, the flow direction of the first regulating control valve 23 is A-B, the second regulating control valve 26 is adjusted according to the demand to supply cold to the condenser 3 or the refrigerated storage, and ice is stored, the chilled water of -5-5°C discharged by the chilled water circulation unit 81 is delivered by the first water pump 22 to the ice storage device 24 through the AB interface of the first regulating control valve 23 to exchange heat and store ice, and finally returned to the chilled water circulation unit 81 through the second regulating control valve 26, the condenser 3 or the refrigerated air cooler 9 and a pipeline.

[0049] When the water-cooled cascade cycle loop is used to melt ice alone, the chilled water circulation unit 81 is not operated after ice storage, the ice storage cold is used to cool the refrigerated storage or condense CO2, the first regulating control valve 23 and the second regulating control valve 26 are adjusted according to the demand and opened, the chilled water of 5-9°C discharged by the chilled water unit 8 is delivered by the first water pump 22 to the ice storage device 24 through the AB interface of the first regulating control valve 23 to melt ice, and finally returned to the chilled water unit 8 through the second regulating control valve 26, the condenser 3 or the refrigerated air cooler 9 and a pipeline.

[0050] When the water-cooling cascade circulation loop carries out ice-melting cooling, the water chiller 8 also operates, the first regulating control valve 23 and the second regulating control valve 26 are switched to be adjusted according to the demand and opened, the 5-9℃ cold water is discharged by the water chiller 8 through the first water pump 22, the flow direction of the first regulating control valve 23 is A-B to enter the ice storage device 24, and the cold water is heated in the condenser 3 or the refrigeration air cooler 9 through the second regulating control valve 26, is finally returned to the water chiller 8 through the pipeline.

[0051] When the water-cooling cascade circulation loop carries out normal refrigeration cycle, the water chiller 8 operates, the first regulating control valve 23 and the second regulating control valve 26 are switched to be adjusted according to the demand and opened, the -5-5℃ cold water is discharged by the water chiller 8 through the first water pump 22, the flow direction of the first regulating control valve 23 is A-C, and the cold water is heated in the condenser 3 or the refrigeration air cooler 9 through the second regulating control valve 26, is finally returned to the water chiller 8 through the pipeline.

[0052] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A carbon dioxide water-cooled cascade system, characterized by: The carbon dioxide circulation loop comprises a compression refrigeration cycle and a condenser, the condenser is provided with a carbon dioxide heat exchange pipeline and a water cooling heat exchange pipeline, the carbon dioxide heat exchange pipeline is connected with the carbon dioxide circulation loop, and the water cooling heat exchange pipeline is connected with the water cooling cascade circulation loop. The water cooling cascade circulation loop comprises a cold water unit, a cold air cooler, a cooling tower, an ice storage device and a water pump, the cold water unit comprises a chilled water circulation unit and a cooling water circulation unit, the water inlet and the water outlet of the cooling water circulation unit are communicated with the pipeline of the cooling tower to form a cooling water circulation pipeline, and the cooling water circulation pipeline is provided with a second water pump. The chilled water circulation pipeline is formed by the chilled water circulation unit, the ice storage device, the cold air cooler and the water cooling heat exchange pipeline, the water outlet pipeline of the chilled water circulation unit is communicated with a first regulating control valve, the first regulating control valve is communicated with the water inlet pipeline of the ice storage device, the first regulating control valve and the water outlet of the ice storage device are communicated with a second regulating control valve through a first branch pipeline, the first branch pipeline is provided with a temperature sensor, the temperature sensor is signal-connected with the first regulating control valve, the second regulating control valve is communicated with the water inlet of the condenser water cooling heat exchange pipeline through a pipeline, and the second regulating control valve is also communicated with the water outlet pipeline of the cold air cooler through a water cooling electromagnetic valve.

2. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: The carbon dioxide circulation loop comprises a carbon dioxide compressor unit, an oil separator, a condenser, a carbon dioxide heat exchange pipeline, a carbon dioxide liquid storage device, a carbon dioxide refrigeration pump and a heat regenerator which are sequentially communicated with each other.

3. A carbon dioxide water cooled cascade system according to claim 2, wherein: In the carbon dioxide circulation loop, the output end of the carbon dioxide refrigeration pump is communicated with the first inlet of the heat regenerator through a first straight-through stop valve pipeline and is communicated with the inlet of the low-temperature air cooler through a second straight-through stop valve pipeline, the first outlet of the heat regenerator is communicated with the connecting pipeline between the second straight-through stop valve and the inlet of the low-temperature air cooler, the connecting pipeline is provided with an electronic expansion valve, the outlet of the low-temperature air cooler is communicated with the second inlet of the heat regenerator through a first electromagnetic valve and a third straight-through stop valve pipeline, and the second outlet of the heat regenerator is communicated with the carbon dioxide compressor unit. When the compression refrigeration cycle is started, the carbon dioxide compressor unit, the condenser, the carbon dioxide refrigeration pump and the low-temperature air cooler in the carbon dioxide circulation loop are operated, and the first straight-through stop valve, the second straight-through stop valve, the electronic expansion valve, the first electromagnetic valve and the third straight-through stop valve are opened.

4. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: When the water-cooled cascade circulation loop carries out high-temperature stage compression cycle, the first regulating control valve is closed with the connection port of the ice storage device, the second regulating control valve is connected with the open port, the water-cooled electromagnetic valve is opened, and the first water pump circulates the chilled water discharged from the chilled water circulating unit to the refrigeration air cooler and the condenser water-cooled heat exchange pipeline to absorb heat and then returns to the chilled water circulating unit for cooling.

5. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: When the water-cooled cascade circulation loop carries out refrigeration air cooler cooling alone, the first regulating control valve is closed with the connection port of the ice storage device, the second regulating control valve is closed with the connection port of the condenser water-cooled heat exchange pipeline, the water-cooled electromagnetic valve is opened, and the first water pump circulates the chilled water discharged from the chilled water circulating unit to the refrigeration air cooler to absorb heat and then returns to the chilled water circulating unit for cooling.

6. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: When the water-cooled cascade circulation loop carries out condenser water-cooled heat exchange pipeline cooling alone, the first regulating control valve is closed with the connection port of the ice storage device, the second regulating control valve is closed with the connection port of the refrigeration air cooler, the first water pump circulates the chilled water discharged from the chilled water circulating unit to the condenser water-cooled heat exchange pipeline to absorb heat and then returns to the chilled water circulating unit for cooling.

7. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: When the water-cooled cascade circulation loop carries out ice storage and refrigeration air cooler cooling and condenser water-cooled heat exchange pipeline cooling, the first regulating control valve is closed with the connection port of the second regulating control valve, the second regulating control valve is connected with the open port, the water-cooled electromagnetic valve is opened, and the first water pump circulates the chilled water discharged from the chilled water circulating unit to the ice storage device, the refrigeration air cooler and the condenser water-cooled heat exchange pipeline to absorb heat and then returns to the chilled water circulating unit for cooling.

8. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: When the water-cooled cascade circulation loop carries out ice melting cooling alone, the first regulating control valve and the second regulating control valve are connected with the open port, the chilled water circulating unit is not started, and the first water pump circulates the chilled water in the chilled water circulating unit to the ice storage device to melt ice, then to the refrigeration air cooler for cooling and to the condenser water-cooled heat exchange pipeline for cooling and then returns to the chilled water circulating unit.

9. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: When the water-cooled cascade circulation loop carries out ice melting cooling, the first regulating control valve and the second regulating control valve are connected with the open port, the chilled water circulating unit is started, and the first water pump circulates the chilled water in the chilled water circulating unit to the ice storage device to melt ice, then to the refrigeration air cooler for cooling and to the condenser water-cooled heat exchange pipeline for cooling and then returns to the chilled water circulating unit.

10. A carbon dioxide water cooled cascade system as claimed in claim 1, wherein: When the water-cooled cascade circulation loop carries out conventional refrigeration cycle, the first regulating control valve is closed with the connection port of the ice storage device, the second regulating control valve is connected with the open port, the chilled water circulating unit is started, and the first water pump circulates the chilled water in the chilled water circulating unit to the refrigeration air cooler for cooling and to the condenser water-cooled heat exchange pipeline for cooling and then returns to the chilled water circulating unit.

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