Water chilling unit capable of achieving multi-stage cold storage

Abstract

The utility model discloses a water chilling unit capable of achieving multi-stage cold accumulation. The water chilling unit comprises a cold accumulation box, a controller, a cold accumulation pipeline part, a first refrigeration unit and a second refrigeration unit. The other side of the cold storage box is used for conveying a cold source to the tail end; one side of the cold storage box, the first refrigeration unit and the second refrigeration unit are sequentially connected end to end through a cold storage pipeline part; the cold storage pipeline part comprises a third temperature sensor, and the third temperature sensor is arranged on a connecting pipeline between the output end of one side of the cold storage box and the second input end of the first refrigeration unit; the first refrigeration unit comprises a first compressor, and the second refrigeration unit comprises a second compressor; according to the water chilling unit capable of achieving multi-stage cold accumulation, a large amount of refrigerating capacity is circularly stored in the cold accumulation box, and when the water chilling unit needs the large amount of refrigerating capacity within a short time or intermittently needs the large amount of refrigerating capacity, the large amount of refrigerating capacity can be released through the cold accumulation box so as to meet the use requirements of the water chilling unit in special occasions.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of cold storage, especially to a cold water unit with multiple levels of cold storage. BACKGROUND

[0002] The general cold water unit widely existing in the market at present can effectively realize the refrigeration function, and provide continuous and uniform cold water supply for the environment with comfort or process requirements. This kind of traditional cold water unit is generally applicable to the occasions with continuous and uniform refrigeration capacity demand. However, when facing the situation of uneven refrigeration capacity demand, such as the need for a large amount of refrigeration capacity in a short time or the need for a large amount of refrigeration capacity in an intermittent manner, this kind of traditional cold water unit is not satisfactory. Since the traditional cold water unit cannot quickly provide the required large amount of refrigeration capacity in a short time, it cannot meet the needs of the occasions with a large amount of refrigeration capacity in a short time or in an intermittent manner.

[0003] This limitation leads to the fact that the traditional cold water unit cannot provide sufficient cooling effect for the process equipment with rapid large heat dissipation capacity, thereby greatly reducing the reliability of equipment operation. In order to solve this problem, there is an urgent need for a new type of cold water unit in the market, which can flexibly cope with various refrigeration demands, especially sudden and intermittent high-load cooling demands, to ensure the stable operation of the process equipment and the maximization of production efficiency.

[0004] It can be seen that the prior art needs to be improved and enhanced. INVENTION CONTENTS

[0005] In view of the above shortcomings of the prior art, the purpose of the utility model is to provide a cold water unit with multiple levels of cold storage, which can provide a large amount of refrigeration capacity for the end when a large amount of refrigeration capacity is required in a short time or in an intermittent manner.

[0006] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0007] A cold water unit with multiple levels of cold storage comprises a cold storage tank, a controller, a cold storage pipeline part, a first refrigeration unit and a second refrigeration unit. The other side of the cold storage tank is used to deliver cold source to the end. The side of the cold storage tank, the first refrigeration unit and the second refrigeration unit are sequentially connected in a head-to-tail manner through the cold storage pipeline part. The cold storage pipeline part comprises a third temperature sensor electrically connected with the controller, which is arranged on the connecting pipeline between the output end of the side of the cold storage tank and the second input end of the first refrigeration unit. The first refrigeration unit comprises a first compressor electrically connected with the controller, and the second refrigeration unit comprises a second compressor electrically connected with the controller.

[0008] The cold water unit with multi-stage cold accumulation, wherein the cold accumulation pipeline part further comprises a water pump, a fourth temperature sensor and a fifth temperature sensor electrically connected with the controller respectively; the second output end of the second refrigeration unit is connected with one side input end of the cold accumulation tank through the water pump, and the fifth temperature sensor is arranged on the connecting pipeline between the second output end of the second refrigeration unit and the water pump; and the fourth temperature sensor is arranged on the connecting pipeline between the second output end of the first refrigeration unit and the second input end of the second refrigeration unit.

[0009] The cold water unit with multi-stage cold accumulation, wherein the cold accumulation pipeline part further comprises a flow protector electrically connected with the controller, and the flow protector is arranged on the connecting pipeline between one side output end of the cold accumulation tank and the second input end of the first refrigeration unit.

[0010] The cold water unit with multi-stage cold accumulation, wherein the first refrigeration unit further comprises a first evaporator, a first condenser, a first filter, a first expansion valve, a first condensing fan, a first pressure sensor, a first temperature sensor, a second pressure sensor and a second temperature sensor electrically connected with the controller; the first evaporator, the first compressor, the first condenser, the first filter and the first expansion valve are sequentially and circularly connected to form a first refrigeration cycle; the first temperature sensor and the first pressure sensor are arranged on the connecting pipeline between the first compressor and the first condenser; and the second temperature sensor and the second pressure sensor are arranged on the connecting pipeline between the first evaporator and the first compressor.

[0011] The cold water unit with multi-stage cold accumulation, wherein the second refrigeration unit further comprises a second evaporator, a second condenser, a second filter, a second expansion valve, a second condensing fan, a third pressure sensor, a sixth temperature sensor, a fourth pressure sensor and a seventh temperature sensor electrically connected with the controller; the second evaporator, the second compressor, the second condenser, the second filter and the second expansion valve are sequentially and circularly connected to form a second refrigeration cycle; the sixth temperature sensor and the third pressure sensor are arranged on the connecting pipeline between the second compressor and the second condenser; and the seventh temperature sensor and the fourth pressure sensor are arranged on the connecting pipeline between the second evaporator and the second compressor.

[0012] The cold water unit with multi-stage cold accumulation, wherein the first refrigeration unit further comprises a first bypass pipeline part electrically connected with the controller, one end of the first bypass pipeline part is connected with the connecting pipeline between the first compressor and the first condenser, and the other end of the bypass pipeline part is connected with the first output end of the first evaporator.

[0013] The second refrigeration unit further comprises a second bypass pipeline part electrically connected with the controller, one end of the second bypass pipeline part is connected with the connecting pipeline of the second compressor and the second condenser, and the other end of the bypass pipeline part is connected with the second output end of the second evaporator.

[0014] The first bypass pipeline part comprises a first bypass on-off valve, a first bypass regulating valve and a first throttling device, one end of the first bypass on-off valve is connected with the connecting pipeline of the first compressor and the first condenser, the other end of the first bypass on-off valve is connected with the first output end of the first evaporator through the first bypass regulating valve and the first throttling device connected in sequence.

[0015] The second bypass pipeline part comprises a second bypass on-off valve, a second bypass regulating valve and a second throttling device, one end of the second bypass on-off valve is connected with the connecting pipeline of the second compressor and the second condenser, and the other end of the second bypass on-off valve is connected with the second output end of the second evaporator through the second bypass regulating valve and the second throttling device connected in sequence.

[0016] The second output end of the second evaporator is connected with the flow distributor through the one side input end of the cold storage tank, and the output end of the flow equalizer is connected with the second input end of the first evaporator through the one side output end of the cold storage tank.

[0017] Beneficial effects:

[0018] The utility model provides a kind of multi-stage cold storage water chilling unit, when water chilling unit needs cold storage, a large amount of refrigeration capacity is stored in cold storage tank by first refrigeration unit and second refrigeration unit circulation, when water chilling unit needs a large amount of refrigeration capacity in short time or intermittently needs a large amount of refrigeration capacity, a large amount of refrigeration capacity is released by cold storage tank, to meet the use demand of water chilling unit in special occasion;Further, according to the real-time third temperature information fed back by third temperature sensor, the working state of first compressor and second compressor is adjusted, to ensure that the cold capacity in cold storage tank can meet the demand of cold storage temperature, so as to ensure the sufficient supply of cold capacity, meet the large refrigeration capacity use demand when water chilling unit executes refrigeration mode;Further, first refrigeration unit is used to store cold in cold storage tank with second refrigeration unit, multi-stage circulating water cooling technology is used, low-grade cold source can be efficiently utilized, the overall energy efficiency ratio of multi-stage cold storage water chilling unit is significantly improved, not only the energy use efficiency is optimized, but also energy consumption is greatly reduced, realizes the dual goal of energy saving and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1The structure schematic diagram of the water chiller with multi-stage cold storage provided by the utility model is provided.

[0020] Figure 2 The electric control structure diagram of the water chiller with multi-stage cold storage provided by the utility model is provided.

[0021] Main element symbol explanation: 1-cold storage tank, 11-diffuser, 12-flow distributor, 21-water pump, 22-flow protector, 23-third temperature sensor, 24-fourth temperature sensor, 25-fifth temperature sensor, 301-first compressor, 302-first condenser, 303-first filter, 304-first expansion valve, 305-first evaporator, 306-first condensing fan, 307-first temperature sensor, 308-first pressure sensor, 309-second temperature sensor, 310-second pressure sensor, 311-first bypass regulating valve, 312-first bypass on-off valve, 313-first throttling device, 401-second compressor, 402-second condenser, 403-second filter, 404-second expansion valve, 405-second evaporator, 406-second condensing fan, 407-sixth temperature sensor, 408-third pressure sensor, 409-seventh temperature sensor, 410-fourth pressure sensor, 411-second bypass regulating valve, 412-second bypass on-off valve, 413-second throttling device, 5-controller. DETAILED DESCRIPTION

[0022] The utility model provides a kind of water chiller with multi-stage cold storage, to make the purpose, technical scheme and effect of the utility model more clear, definite, the following referring to attached drawing and taking example to the utility model is further detailed.

[0023] In the description of the utility model, it is understood that the terms "mounting", "connection" and the like should be broadly understood, and those skilled in the art can understand the specific meaning of the above terms in the utility model according to specific circumstances.

[0024] Please refer to Figure 1 And Figure 2The utility model provides a kind of multistage cold accumulation water chilling unit, including cold storage tank 1, controller 5, cold storage pipeline part, first refrigeration unit and second refrigeration unit;The other side of the cold storage tank 1 is used to deliver cold source to end;The side of the cold storage tank 1, the first refrigeration unit and the second refrigeration unit are sequentially connected by the cold storage pipeline part;The cold storage pipeline part includes the third temperature sensor 23 electrically connected with the controller 5, the third temperature sensor 23 is arranged on the connecting pipeline of the side output end of the cold storage tank 1 and the second input end of the first refrigeration unit;The first refrigeration unit includes the first compressor 301 electrically connected with the controller 5, and the second refrigeration unit includes the second compressor 401 electrically connected with the controller 5.

[0025] The application discloses a kind of multistage cold accumulation water chilling unit, when water chilling unit needs cold accumulation, i.e. when controller 5 detects that water chilling unit executes cold accumulation mode, a large amount of refrigeration capacity is stored in cold storage tank 1 by first refrigeration unit and second refrigeration unit circulation, when water chilling unit needs a large amount of refrigeration capacity in short time or intermittently needs a large amount of refrigeration capacity, a large amount of refrigeration capacity is released by cold storage tank 1, to meet the use demand of water chilling unit in special occasion;Further, according to the real-time third temperature information fed back by third temperature sensor 23 Adjustment the working state of first compressor 301 and second compressor 401, ensure that the cold capacity in cold storage tank 1 can meet the demand of cold accumulation temperature, to guarantee the sufficient supply of cold capacity, meet the large refrigeration capacity use demand when water chilling unit executes refrigeration mode;Further, first refrigeration unit is used to store cold in cold storage tank 1 with second refrigeration unit, using multistage circulating water cooling technology, can efficiently utilize low-grade cold source, significantly improve the overall energy efficiency ratio of multistage cold accumulation water chilling unit, not only optimize the energy use efficiency, but also greatly reduce energy consumption, realize the dual goal of energy saving and environmental protection.

[0026] In the embodiment, the controller 5 is the controller 5 of the existing water chilling unit, which is not described herein.

[0027] In the embodiment, please refer to Figure 1 The other side of the cold storage tank 1 is provided with a cold water supply pipe and a cold water return pipe, and the cold water supply pipe and the cold water return pipe are respectively used to connect the end to deliver the cold source to the end.

[0028] Further, please refer to Figure 1 And Figure 2, the cold storage pipeline part further comprises a water pump 21, a fourth temperature sensor 24 and a fifth temperature sensor 25 which are electrically connected with the controller 5 respectively; the second output end of the second refrigeration unit is connected with one side of the input end of the cold storage tank 1 through the water pump 21, and the fifth temperature sensor 25 is arranged on the connecting pipeline between the second output end of the second refrigeration unit and the water pump 21; and the fourth temperature sensor 24 is arranged on the connecting pipeline between the second output end of the first refrigeration unit and the second input end of the second refrigeration unit.

[0029] In the embodiment, the water pump 21 is used to realize heat exchange circulation between the cold storage tank 1 and the first refrigeration unit and the second refrigeration unit.

[0030] Further, the fourth temperature sensor 24 is arranged at the second output end of the first evaporator 305, and the temperature of the cold source output by the second output end is relatively low after being cooled; when the outlet water temperature is lower than the preset protection action temperature, the second evaporator 405 is extremely easy to freeze, and after freezing, the volume is expanded to crack the second evaporator 405, resulting in damage of the second evaporator 405; therefore, a protection mechanism is arranged for the second evaporator 405 according to the fourth temperature information, and when the fourth temperature information is lower than the preset protection action temperature, the first compressor 301 needs to be controlled to stop and stop refrigeration, so as to prevent the cold water unit from being frozen.

[0031] Further, the fifth temperature sensor 25 is arranged at the second output end of the second evaporator 405, and the temperature of the cold source output by the second output end is relatively low after being cooled; when the outlet water temperature is lower than the preset protection action temperature, the second evaporator 405 is extremely easy to freeze, and after freezing, the volume is expanded to crack the second evaporator 405, resulting in damage of the second evaporator 405; therefore, a protection mechanism is arranged for the second evaporator 405 according to the fifth temperature information, and when the fifth temperature information is lower than the preset protection action temperature, the second compressor 401 needs to be controlled to stop and stop refrigeration, so as to prevent the cold water unit from being frozen.

[0032] Further, referring to Figure 1 and Figure 2 , the cold storage pipeline part further comprises a flow protector 22 which is electrically connected with the controller 5, and the flow protector 22 is arranged on the connecting pipeline between one side of the output end of the cold storage tank 1 and the second input end of the first refrigeration unit.

[0033] In the embodiment, when the flow protector 22 detects an abnormal situation and disconnects, the controller 5 will quickly respond, automatically control the first compressor 301 and the second compressor 401 to stop, and simultaneously output a flow interruption alarm signal, so as to avoid damage of the equipment caused by flow abnormality, and also remind the operator to take corresponding measures in time, so as to greatly improve the safety performance of the cold water unit during operation.

[0034] Further, referring to Figure 1 and Figure 2 , the first refrigeration unit further comprises a first evaporator 305, a first condenser 302, a first filter 303, a first expansion valve 304, and a first condensing fan 306, a first pressure sensor 308, a first temperature sensor 307, a second pressure sensor 310 and a second temperature sensor 309 electrically connected with the controller 5; the first evaporator 305, the first compressor 301, the first condenser 302, the first filter 303 and the first expansion valve 304 are sequentially connected end to end to form a first refrigeration cycle; the first temperature sensor 307 and the first pressure sensor 308 are arranged on the connecting pipeline between the first compressor 301 and the first condenser 302; the second temperature sensor 309 and the second pressure sensor 310 are arranged on the connecting pipeline between the first evaporator 305 and the first compressor 301.

[0035] In the embodiment, the first temperature sensor 307 and the first pressure sensor 308 are arranged on the connecting pipeline between the first compressor 301 and the first condenser 302, for monitoring the state of the high-temperature and high-pressure refrigerant discharged from the first compressor 301 in real time, to ensure that it reaches the ideal temperature and pressure before entering the first condenser 302; while the second temperature sensor 309 and the second pressure sensor 310 are arranged on the connecting pipeline between the first evaporator 305 and the first compressor 301, responsible for monitoring the state of the low-temperature and low-pressure refrigerant returned from the first evaporator 305 to the first compressor 301, to ensure that the refrigerant reaches the appropriate conditions before re-entering the first compressor 301.

[0036] Further, referring to Figure 1 and Figure 2 , the second refrigeration unit further comprises a second evaporator 405, a second condenser 402, a second filter 403, a second expansion valve 404, and a second condensing fan 406, a third pressure sensor 408, a sixth temperature sensor 407, a fourth pressure sensor 410 and a seventh temperature sensor 409 electrically connected with the controller 5; the second evaporator 405, the second compressor 401, the second condenser 402, the second filter 403 and the second expansion valve 404 are sequentially connected end to end to form a second refrigeration cycle; the sixth temperature sensor 407 and the third pressure sensor 408 are arranged on the connecting pipeline between the second compressor 401 and the second condenser 402; the seventh temperature sensor 409 and the fourth pressure sensor 410 are arranged on the connecting pipeline between the second evaporator 405 and the second compressor 401.

[0037] In this embodiment, the sixth temperature sensor 407 and the third pressure sensor 408 are arranged on the connecting pipeline between the second compressor 401 and the second condenser 402, for monitoring the state of the high-temperature and high-pressure refrigerant discharged from the second compressor 401 in real time, to ensure that it reaches the desired temperature and pressure before entering the second condenser 402; while the seventh temperature sensor 409 and the fourth pressure sensor 410 are located on the connecting pipeline between the second evaporator 405 and the second compressor 401, responsible for monitoring the state of the low-temperature and low-pressure refrigerant returning from the second evaporator 405 to the second compressor 401, to ensure that the refrigerant reaches the appropriate conditions before re-entering the second compressor 401.

[0038] In this embodiment, for the structure of the first refrigeration unit and the second refrigeration unit, the evaporator is responsible for absorbing heat from the environment as the starting point of the refrigeration cycle, while the compressor compresses the refrigerant to increase its temperature and pressure, so as to release heat in the condenser; the condenser is the key part of the system, which effectively reduces the temperature of the refrigerant with the assistance of the condenser fan, ensuring efficient heat dissipation; the filter and the expansion valve are responsible for removing impurities in the refrigerant and adjusting the flow of the refrigerant, respectively, to ensure smooth operation of the entire system.

[0039] Further, referring to Figure 1 and Figure 2 , the first refrigeration unit further comprises a first bypass pipeline portion electrically connected with the controller 5, one end of the first bypass pipeline portion being connected with the connecting pipeline of the first compressor 301 and the first condenser 302, and the other end of the bypass pipeline portion being connected with the first output end of the first evaporator 305.

[0040] Further, referring to Figure 1 and Figure 2 , the second refrigeration unit further comprises a second bypass pipeline portion electrically connected with the controller 5, one end of the second bypass pipeline portion being connected with the connecting pipeline of the second compressor 401 and the second condenser 402, and the other end of the bypass pipeline portion being connected with the second output end of the second evaporator 405.

[0041] In the embodiment, by setting the first bypass pipeline part and the second bypass pipeline part, when the exhaust pressure of the first compressor 301 or the second compressor 401 greatly rises and is higher than the preset bypass working pressure range, the first bypass pipeline part and the second bypass pipeline part start to work, and a part of the refrigerant of the high-pressure exhaust of the first compressor 301 or the second compressor 401 is bypassed in time to enter the suction port of the first compressor 301 or the second compressor 401, so that even when the ambient temperature is very high and the first condensing fan 306 or the second condensing fan 406 is insufficiently cooled, pressure relief can be performed through the first bypass pipeline part or the second bypass pipeline part, thereby ensuring that the first compressor 301 and the second compressor 401 can still be stably and reliably operated at a very high ambient temperature.

[0042] Further, referring to Figure 1 and Figure 2 , the first bypass pipeline part comprises a first bypass on-off valve 312, a first bypass regulating valve 311, and a first throttling device 313, one end of the first bypass on-off valve 312 is connected with the connecting pipeline of the first compressor 301 and the first condenser 302, the other end of the first bypass on-off valve 312 is connected with the first output end of the first evaporator 305 through the first bypass regulating valve 311 and the first throttling device 313 connected in sequence.

[0043] Further, referring to Figure 1 and Figure 2 , the second bypass pipeline part comprises a second bypass on-off valve 412, a second bypass regulating valve 411, and a second throttling device 413, one end of the second bypass on-off valve 412 is connected with the connecting pipeline of the second compressor 401 and the second condenser 402, the other end of the second bypass on-off valve 412 is connected with the second output end of the second evaporator 405 through the second bypass regulating valve 411 and the second throttling device 413 connected in sequence.

[0044] In the embodiment, for the two bypass pipeline parts, when the bypass pipeline part starts to work, the controller 5 controls the corresponding bypass on-off valve to open to turn on the bypass pipeline, and the corresponding bypass regulating valve is opened according to the preset opening degree; when the bypass pipeline part stops working, the controller 5 controls the bypass on-off valve and the bypass regulating valve to close to close the bypass pipeline.

[0045] Further, referring to Figure 1 and Figure 2 , the cold storage tank 1 is provided with a flow distributor 11 and a flow equalizer 12, the second output end of the second evaporator 405 is connected with the flow distributor 11 through one side of the input end of the cold storage tank 1, and the output end of the flow equalizer 12 is connected with the second input end of the first evaporator 305 through one side of the output end of the cold storage tank 1.

[0046] In the present embodiment, by setting the flow distributor 11 and the flow equalizer 12 in the cold storage tank 1, the cooling efficiency and performance of the cold storage mechanism are significantly improved. First, the introduction of the flow distributor 11 enables the coolant to be evenly distributed throughout the cold storage tank 1, avoiding the problem of uneven cooling effect caused by the accumulation of coolant in certain areas. This uniform distribution feature ensures that every corner is fully cooled, thereby improving the overall cold storage efficiency. Second, the introduction of the flow distributor 11 optimizes the flow path of the coolant, reduces the flow resistance, and further improves the flow efficiency of the coolant. In addition, the flow equalizer 12 connected between the output end of one side of the cold storage tank 1 and the second input end of the first evaporator 305 ensures that the coolant can be uniformly mixed and distributed before returning to the first evaporator 305. This uniform flow feature not only improves the utilization efficiency of the coolant, but also ensures that the first evaporator 305 can operate in the best state, thereby improving the cold storage effect of the cold storage mechanism.

[0047] It can be understood that for those skilled in the art, equivalent replacements or changes can be made according to the technical scheme and the utility model concept of the present utility model, and all these changes or replacements shall belong to the protection scope of the present utility model.

Claims

1. A multi-stage cold storage water chiller, characterized in that, The application relates to a cold storage device, which comprises a cold storage tank, a controller, a cold storage pipeline part, a first refrigeration unit and a second refrigeration unit; the other side of the cold storage tank is used for delivering cold sources to the end; one side of the cold storage tank, the first refrigeration unit and the second refrigeration unit are sequentially and circularly connected through the cold storage pipeline part; the cold storage pipeline part comprises a third temperature sensor which is electrically connected with the controller, and the third temperature sensor is arranged on a connecting pipeline between a one-side output end of the cold storage tank and a second input end of the first refrigeration unit; the first refrigeration unit comprises a first compressor which is electrically connected with the controller, and the second refrigeration unit comprises a second compressor which is electrically connected with the controller.

2. The multi-stage cold accumulating water chiller according to claim 1, characterized in that, The cold storage pipeline part further comprises a water pump, a fourth temperature sensor and a fifth temperature sensor which are electrically connected with the controller respectively; a second output end of the second refrigeration unit is connected with a one-side input end of the cold storage tank through the water pump, and the fifth temperature sensor is arranged on a connecting pipeline between the second output end of the second refrigeration unit and the water pump; the fourth temperature sensor is arranged on a connecting pipeline between a second output end of the first refrigeration unit and a second input end of the second refrigeration unit.

3. The multi-stage cold accumulating water chiller according to claim 2, characterized in that, The cold storage pipeline part further comprises a flow protector which is electrically connected with the controller, and the flow protector is arranged on a connecting pipeline between a one-side output end of the cold storage tank and a second input end of the first refrigeration unit.

4. The multi-stage cold accumulating water chiller according to claim 1, characterized in that, The first refrigeration unit further comprises a first evaporator, a first condenser, a first filter, a first expansion valve, a first condensing fan, a first pressure sensor, a first temperature sensor, a second pressure sensor and a second temperature sensor which are electrically connected with the controller; the first evaporator, the first compressor, the first condenser, the first filter and the first expansion valve are sequentially and circularly connected to form a first refrigeration cycle; the first temperature sensor and the first pressure sensor are arranged on a connecting pipeline between the first compressor and the first condenser; The second temperature sensor and the second pressure sensor are arranged on a connecting pipeline between the first evaporator and the first compressor.

5. The multi-stage cold accumulating water chiller according to claim 4, characterized in that, The second refrigeration unit further comprises a second evaporator, a second condenser, a second filter, a second expansion valve, a second condensing fan, a third pressure sensor, a sixth temperature sensor, a fourth pressure sensor and a seventh temperature sensor which are electrically connected with the controller; the second evaporator, the second compressor, the second condenser, the second filter and the second expansion valve are sequentially and circularly connected to form a second refrigeration cycle; the sixth temperature sensor and the third pressure sensor are arranged on a connecting pipeline between the second compressor and the second condenser; The seventh temperature sensor and the fourth pressure sensor are arranged on a connecting pipeline between the second evaporator and the second compressor.

6. The multi-stage cold accumulating water chiller according to claim 5, characterized in that, The first refrigeration unit further comprises a first bypass pipeline part which is electrically connected with the controller, one end of the first bypass pipeline part is connected with a connecting pipeline between the first compressor and the first condenser, and the other end of the bypass pipeline part is connected with a first output end of the first evaporator.

7. The multi-stage cold accumulating water chiller according to claim 6, characterized in that, The second refrigeration unit further comprises a second bypass pipeline part electrically connected with the controller, one end of the second bypass pipeline part is connected with the connecting pipeline of the second compressor and the second condenser, and the other end of the bypass pipeline part is connected with the second output end of the second evaporator.

8. The multi-stage cold accumulating water chiller according to claim 7, characterized in that, The first bypass pipeline part comprises a first bypass on-off valve, a first bypass regulating valve and a first throttling device, one end of the first bypass on-off valve is connected with the connecting pipeline of the first compressor and the first condenser, and the other end of the first bypass on-off valve is connected with the first output end of the first evaporator through the first bypass regulating valve and the first throttling device connected in sequence.

9. The multi-stage cold accumulating water chiller according to claim 7, characterized in that, The second bypass pipeline part comprises a second bypass on-off valve, a second bypass regulating valve and a second throttling device, one end of the second bypass on-off valve is connected with the connecting pipeline of the second compressor and the second condenser, and the other end of the second bypass on-off valve is connected with the second output end of the second evaporator through the second bypass regulating valve and the second throttling device connected in sequence.

10. The multi-stage cold accumulating water chiller according to claim 5, characterized in that, The cold storage tank is provided with a flow distributor and a flow equalizer, the second output end of the second evaporator is connected with the flow distributor through a side input end of the cold storage tank, and the output end of the flow equalizer is connected with the second input end of the first evaporator through a side output end of the cold storage tank.

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