Low-temperature cold accumulation unit capable of preventing plate heat exchanger from freezing

Abstract

The utility model relates to a low-temperature cold storage unit for preventing a plate heat exchanger from freezing, which comprises a low-temperature refrigerating unit, the plate heat exchanger and an energy storage water tank which are mutually connected through pipelines, the energy storage water tank is divided into a low-temperature end and a high-temperature end by a partition plate with a communication hole, and energy storage media are filled in the energy storage water tank. The pipelines are respectively provided with a sensor group, the sensor groups provide pipeline data for the intelligent frequency conversion control cabinet, and the intelligent frequency conversion control cabinet controls the control valves and the circulating water pumps installed on the pipelines according to the pipeline data so as to adjust the flow in the pipelines. In order to solve the problem of blockage caused by freezing of chilled water on a user side in the heat exchange process of 60% ethylene glycol secondary refrigerant of-30 DEG C, a temperature sensor is arranged on a pipeline on the user side and is connected with a controller, and meanwhile, the controller adjusts the temperature and flow of chilled water on a cold source side according to the temperature fed back by the temperature sensor; the problem of icing and blocking is avoided, and normal operation of the system is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of cold storage units, in particular to a low-temperature cold storage unit for preventing a plate heat exchanger from freezing. Background Art

[0002] The low-temperature cold storage plate heat exchanger is a system that uses off-peak electricity to store refrigerant and provides low-temperature chilled water through a heat exchanger during the day. This system can achieve peak shaving and valley filling, use cheap electricity for refrigeration, and improve energy efficiency. In similar systems, refrigerants such as ethylene glycol are often used for low-temperature energy storage, and heat is exchanged with the user-side water system through a brazed plate heat exchanger to provide low-temperature chilled water. This system can effectively maintain a stable temperature of the user-side water system during daytime operation, while realizing the use of peak and valley electricity prices.

[0003] However, in actual use, it was found that during the heat exchange process of 60% ethylene glycol refrigerant at -30℃, there was a problem of freezing and clogging of the user-side chilled water. This is because the freezing point of ethylene glycol is low. When the low-temperature refrigerant exchanges heat with the user-side chilled water, the water in the water system may condense and freeze, causing pipe blockage and affecting the normal operation of the system. This problem may cause equipment damage, energy waste, and reduced operating efficiency.

[0004] Therefore, it is necessary to design a reasonable control system to control the operation of the low-temperature cold storage unit to solve this problem. The control system should be able to effectively monitor and control the temperature of the chilled water on the user side to prevent ice blockage. At the same time, the control system should also have stable and reliable performance, be able to adapt to the heat exchange requirements under different working conditions, and improve the operating efficiency and safety of the system. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a low-temperature cold storage unit for preventing the plate heat exchanger from freezing, effectively detecting the temperature of the chilled water on the user side, controlling the chilled water flow rate when the chilled water temperature on the user side is too low, preventing the plate heat exchanger from freezing, and ensuring the safe operation of the system.

[0006] The technical solution adopted by the utility model to solve its technical problems is: to provide a low-temperature cold storage unit for preventing a plate heat exchanger from freezing, comprising a low-temperature refrigeration unit, a plate heat exchanger and an energy storage water tank interconnected by pipelines, the energy storage water tank being divided into a low-temperature end and a high-temperature end by a partition provided with a connecting hole, the energy storage water tank being filled with an energy storage medium, the low-temperature refrigeration unit forming a loop through a fourth water outlet pipe and a fourth water return pipe and being connected to a cooling tower, the low-temperature refrigeration unit being connected to the low-temperature end through a first water outlet pipe, the high-temperature end being connected to the low-temperature refrigeration unit through a first water return pipe provided with a circulation pump of the refrigeration unit, the first water outlet pipe and the first water return pipe forming a loop; the low-temperature end being connected to the plate heat exchanger through a second water outlet pipe provided with a circulation pump on the cold source side The plate heat exchanger is connected to the high-temperature end through a second return pipe, the second water outlet pipe and the second return pipe form a loop, the plate heat exchanger forms a loop through a third water outlet pipe and a third return pipe and is connected to the user side, the first water outlet pipe, the first return pipe, the second water outlet pipe, the second return pipe, the third water outlet pipe, the third return pipe, the fourth water outlet pipe and the fourth return pipe are respectively provided with a sensor group, the sensor group provides pipeline data for the intelligent frequency conversion control cabinet, and the intelligent frequency conversion control cabinet controls the control valves and circulating water pumps installed on the first water outlet pipe, the first return pipe, the second water outlet pipe, the second return pipe, the third water outlet pipe, the third return pipe, the fourth water outlet pipe and the fourth return pipe according to the pipeline data to adjust the flow in the pipeline.

[0007] Preferably, the energy storage medium is ethylene glycol solution.

[0008] Preferably, the plate heat exchanger is of brazed type.

[0009] Preferably, the sensor group includes a temperature sensor, a pressure sensor and a flow sensor.

[0010] Preferably, the first water outlet pipe, the first water return pipe, the second water outlet pipe, the second water return pipe, the third water outlet pipe and the third water return pipe are all provided with temperature sensors.

[0011] Preferably, a user-side flow sensor is provided on the third water return pipe or the third water outlet pipe, and a cold source-side flow sensor is provided on the second water outlet pipe or the second water return pipe.

[0012] Preferably, the third water outlet pipe and the third water return pipe are both provided with pressure sensors.

[0013] Beneficial Effects

[0014] The present application provides a low-temperature cold storage unit for preventing a plate heat exchanger from freezing. In order to solve the problem of freezing and blockage of chilled water on the user side during heat exchange with a 60% ethylene glycol refrigerant at -30°C, the present application arranges a temperature sensor on the user side pipeline and connects it to a controller. At the same time, the controller adjusts the temperature and flow of the chilled water on the cold source side according to the temperature feedback from the temperature sensor, thereby avoiding the occurrence of freezing and blockage problems and ensuring the normal operation of the system.

[0015] In addition, compared with the prior art, this technical solution also has the following beneficial effects:

[0016] 1. Nighttime off-peak electricity cooling: By utilizing off-peak electricity for cooling operations, peak load shifting and valley filling can be achieved, effectively reducing the load on the power grid during the day and improving the stability and power supply capacity of the power grid.

[0017] 2. Cold storage and energy storage: Using energy storage tanks to store low-temperature coolants can be used for cooling during the night when electricity is off-peak, and supply the user-side water system during the daytime peak period to achieve a stable supply of chilled water. This method can reduce the load on the power grid during the day, reduce energy consumption and costs.

[0018] 3. Brazed plate heat exchanger: Using brazed plate heat exchanger for heat exchange operation can effectively improve heat exchange efficiency and performance and reduce energy loss.

[0019] In summary, this technical solution can effectively achieve peak load reduction and valley filling, prevent plate heat exchangers from freezing and cracking, and improve system stability, energy saving and operating efficiency through nighttime low-peak electric refrigeration, cold storage, brazed plate heat exchangers and reasonable control systems. Compared with the existing technology, this technical solution has higher energy utilization efficiency and lower operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The diagram is a circuit diagram of a low-temperature cold storage unit for preventing the plate heat exchanger from freezing.

[0021] Figure 2 for Figure 1 A schematic diagram of a circuit connecting a low-temperature cold storage unit for preventing a plate heat exchanger from freezing and an intelligent frequency conversion control cabinet.

[0022] Among them, 1-user side water supply pipe electric valve; 2-user side water supply pipe temperature sensor; 3-user side water supply pipe pressure sensor; 4-user side return pipe pressure sensor; 5-user side return pipe temperature sensor; 6-user side flow sensor; 7-user side return pipe electric valve; 8-user side circulation pump; 9-plate heat exchanger; 10-cold source side water supply electric regulating valve; 11-cold source side circulation pump; 12-cold source side water supply temperature sensor; 13-cold source side water supply electric valve; 14-cold source side return water electric valve; 15-cold source side return water temperature sensor; 16-cold source side flow sensor 1-refrigeration unit flow sensor; 17-refrigeration unit flow switch; 18-refrigeration unit water supply butterfly valve; 19-refrigeration unit water supply temperature sensor; 20-refrigeration unit water supply electric valve; 21-refrigeration unit return water butterfly valve; 22-refrigeration unit circulation pump; 23-refrigeration unit return water temperature sensor; 24-refrigeration unit return water electric valve; 25-refrigeration unit bypass butterfly valve; 26-cooling water supply butterfly valve; 27-cooling water supply electric valve; 28-cooling water return water butterfly valve; 29-cooling water circulation pump; 30-cooling tower; 31-low-temperature refrigeration unit; 32-energy storage tank; 33-partition.

[0023] The same reference numerals in the various drawings represent the same components. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

[0025] like Figure 1 As shown, a low-temperature cold storage unit for preventing a plate heat exchanger from freezing comprises a low-temperature refrigeration unit 31, a plate heat exchanger 9 and an energy storage water tank 32 which are interconnected by pipelines. The energy storage water tank 32 is divided into a low-temperature end and a high-temperature end by a partition 33 provided with a connecting hole. The energy storage water tank 32 is filled with an energy storage medium. The low-temperature refrigeration unit 31 forms a loop through a fourth water outlet pipe and a fourth water return pipe provided with a cooling water circulation pump 29 and is connected to a cooling tower 30. The low-temperature refrigeration unit 31 is connected to the low-temperature end through a first water outlet pipe. The high-temperature end is connected to the low-temperature refrigeration unit 31 through a first return pipe provided with a refrigeration unit circulation pump 22, and the first outlet pipe and the first return pipe form a loop; the low-temperature end is connected to the plate heat exchanger 9 through a second outlet pipe provided with a cold source side circulation pump 11, and the plate heat exchanger 9 is connected to the high-temperature end through a second return pipe, and the second outlet pipe and the second return pipe form a loop, and the plate heat exchanger 9 forms a loop and is connected to the user side through a third outlet pipe and a third return pipe provided with a user side circulation pump 8. Figure 2 As shown, the first water outlet pipe, the first water return pipe, the second water outlet pipe, the second water return pipe, the third water outlet pipe, the third water return pipe, the fourth water outlet pipe and the fourth water return pipe are respectively provided with sensor groups, and the sensor groups provide pipeline data for the intelligent frequency conversion control cabinet. The intelligent frequency conversion control cabinet controls the control valves and circulating water pumps installed on the first water outlet pipe, the first water return pipe, the second water outlet pipe, the second water return pipe, the third water outlet pipe, the third water return pipe, the fourth water outlet pipe and the fourth water return pipe according to the pipeline data to adjust the flow in the pipeline.

[0026] In a specific embodiment, the energy storage medium is an ethylene glycol solution.

[0027] In a specific embodiment, the plate heat exchanger 9 is of brazed type.

[0028] The sensor group includes a temperature sensor, a pressure sensor and a flow sensor.

[0029] The first water outlet pipe, the first water return pipe, the second water outlet pipe, the second water return pipe, the third water outlet pipe, and the third water return pipe are all provided with temperature sensors. In a specific embodiment, they include a user-side water supply pipe temperature sensor 2, a user-side water return pipe temperature sensor 5, a cold source-side water supply temperature sensor 12, a cold source-side water return temperature sensor 15, a refrigeration unit water supply temperature sensor 19, and a refrigeration unit water return temperature sensor 23.

[0030] In a specific embodiment, a user-side flow sensor 6 is provided on the third water return pipe or the third water outlet pipe, and a cold source-side flow sensor 16 is provided on the second water outlet pipe or the second water return pipe.

[0031] In a specific embodiment, the third water outlet pipe and the third water return pipe are both provided with pressure sensors, including a user-side water supply pipe pressure sensor 3 and a user-side water return pipe pressure sensor 4 .

[0032] The control valve includes a flow switch, a butterfly valve, an electric regulating valve and an electric valve.

[0033] In a specific embodiment, it includes a user-side water supply pipe electric valve 1 arranged on the third water outlet pipe, and a user-side return pipe electric valve 7 on the third return pipe; a cold source side water supply electric regulating valve 10 arranged on the second water outlet pipe, and a cold source side return water electric valve 14 on the second return water pipe; a refrigeration unit flow switch 17, a refrigeration unit water supply butterfly valve 18 and a refrigeration unit water supply electric valve 20 arranged on the first water outlet pipe, a refrigeration unit return water butterfly valve 21 and a refrigeration unit return water electric valve 24 arranged on the first return water pipe; a refrigeration unit bypass butterfly valve 25 arranged on the connecting pipeline between the first return water pipe and the first water outlet pipe; a cooling water supply butterfly valve 26 and a cooling water supply electric valve 27 arranged on the fourth water outlet pipe, and a cooling water return water butterfly valve 28 arranged on the fourth return water pipe.

[0034] In practical applications, an example of control logic of the intelligent frequency conversion control cabinet is as follows:

[0035] 1. When the user-side water supply pipe temperature sensor 2 detects that the temperature of the chilled water begins to drop to nearly 4°C, the controller will send instructions to the cold source side water supply electric regulating valve 10 and the cold source side circulating pump 11 based on the feedback signal of the temperature sensor. The cold source side water supply electric regulating valve 10 is closed and the cold source side circulating pump 11 stops running.

[0036] 2. When the user-side water supply pipe temperature sensor 2 detects that the temperature of the user-side chilled water returns to the normal range of 7-10°C, the controller stops sending instructions, the cold source side water supply electric regulating valve 10 opens, and the cold source side circulation pump 11 restarts.

[0037] Other control logics can be adjusted according to actual conditions. Through the design of the control system, it is possible to effectively prevent the user-side chilled water from freezing and clogging during the heat exchange process of the brazed plate heat exchanger 9 with the 60% ethylene glycol refrigerant at -30°C, thereby ensuring the normal operation of the system.

Claims

1. A low-temperature cold storage unit for preventing a plate heat exchanger from freezing, comprising a low-temperature refrigeration unit, a plate heat exchanger and an energy storage water tank interconnected by pipelines, the energy storage water tank being divided into a low-temperature end and a high-temperature end by a partition provided with a connecting hole, the energy storage water tank being filled with an energy storage medium, the low-temperature refrigeration unit forming a loop and being connected to a cooling tower through a fourth water outlet pipe and a fourth water return pipe, the low-temperature refrigeration unit being connected to the low-temperature end through a first water outlet pipe, the high-temperature end being connected to the low-temperature refrigeration unit through a first water return pipe provided with a refrigeration unit circulating pump, the first water outlet pipe and the first water return pipe forming a loop; the low-temperature end being connected to the plate heat exchanger through a second water outlet pipe provided with a cold source side circulating pump, the plate heat exchanger being connected to the high-temperature end through a second water return pipe, the second water outlet pipe and the second water return pipe forming a loop, the plate heat exchanger forming a loop through a third water outlet pipe and a third water return pipe and being connected to a user side, characterized in that The first water outlet pipe, the first water return pipe, the second water outlet pipe, the second water return pipe, the third water outlet pipe, the third water return pipe, the fourth water outlet pipe and the fourth water return pipe are respectively provided with sensor groups, and the sensor groups provide pipeline data for the intelligent frequency conversion control cabinet. The intelligent frequency conversion control cabinet controls the control valves and circulating water pumps installed on the first water outlet pipe, the first water return pipe, the second water outlet pipe, the second water return pipe, the third water outlet pipe, the third water return pipe, the fourth water outlet pipe and the fourth water return pipe according to the pipeline data to adjust the flow in the pipeline.

2. A low-temperature cold storage unit for preventing the plate heat exchanger from freezing according to claim 1, characterized in that: The energy storage medium is ethylene glycol solution.

3. A low-temperature cold storage unit for preventing the plate heat exchanger from freezing according to claim 1, characterized in that: The plate heat exchanger is of brazing type.

4. A low-temperature cold storage unit for preventing the plate heat exchanger from freezing according to claim 1, characterized in that: The sensor group includes a temperature sensor, a pressure sensor and a flow sensor.

5. A low-temperature cold storage unit for preventing the plate heat exchanger from freezing according to claim 4, characterized in that: The first water outlet pipe, the first water return pipe, the second water outlet pipe, the second water return pipe, the third water outlet pipe and the third water return pipe are all provided with temperature sensors.

6. A low-temperature cold storage unit for preventing the plate heat exchanger from freezing according to claim 4, characterized in that: The third water return pipe or the third water outlet pipe is provided with a user-side flow sensor, and the second water outlet pipe or the second water return pipe is provided with a cold source-side flow sensor.

7. A low-temperature cold storage unit for preventing the plate heat exchanger from freezing according to claim 4, characterized in that: The third water outlet pipe and the third water return pipe are both provided with pressure sensors.

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