A chilled water closed loop system

Abstract

The application provides a chilled water closed circulation system, comprising a water pump, a refrigerator, an evaporator and an exchanger; the water pump, the refrigerator, the evaporator and the exchanger are connected through pipelines and form a circulation loop; the pipeline between the evaporator and the exchanger passes through a production line cooling device; the exchanger is connected with a first valve in series to form an exchanger group, and multiple exchanger groups are connected with a second valve in parallel; the pipeline is provided with a pressure sensor; wherein, the system controls the opening and closing degree of the second valve according to the pressure value fed back by the pressure sensor; when the chilled water amount of the production line is reduced, the working load of the refrigerator is correspondingly reduced, and the water temperature is still stable, the water pressure and flow are constant in the zero load shutdown state, and the maximum energy saving value is achieved.

Description

Technical Field

[0001] This application relates to the field of water supply systems, and more particularly to a closed-loop chilled water circulation system. Background Technology

[0002] For traditional closed-loop chilled water systems, when the system is in operation and the load is in a cooling state, the E / P valves of the heat exchanger are all open to varying degrees or fully open. At this time, the pressure detected by the pressure sensors in the pipeline is between 0.2 MPa and 0.25 MPa, the flow switch flowing through the evaporator of the chiller is closed, and the temperature difference between the inlet and outlet water of the evaporator is <10℃, or even within 4℃ in the most ideal condition. Under these conditions, the system is normal. When the load is in a constant temperature or ultra-low temperature state, the E / P valves of the heat exchanger are all closed to varying degrees or even completely shut off. At this time, the pressure detected by the pressure sensors in the pipeline increases, and a feedback signal is sent to the water pump inverter. The water flow through the evaporator of the chiller decreases, which may cause the flow switch to trip, or the temperature difference between the inlet and outlet water of the evaporator may reach ≥10℃, causing the chiller to alarm and shut down, thus leading to unstable water temperature. Utility Model Content

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0004] The purpose of this application is to at least partially solve one of the technical problems existing in the related technologies. The embodiments of this application provide a closed-loop chilled water system that can achieve constant water temperature and water pressure.

[0005] An embodiment of this application discloses a closed-loop chilled water system, comprising: a water pump, a chiller, an evaporator, and an exchanger; the water pump, the chiller, the evaporator, and the exchanger are connected by pipes to form a circulation loop; the pipe between the evaporator and the exchanger passes through a production line cooling device; the exchanger is connected in series with a first valve to form an exchanger group, and multiple exchanger groups are connected in parallel with a second valve; the pipes are equipped with pressure sensors; wherein, the system controls the opening and closing degree of the second valve based on the pressure value fed back by the pressure sensor.

[0006] According to an embodiment of this application, when the first valve is partially closed, the system controls the second valve to open more based on the pressure value fed back by the pressure sensor; when the first valve is fully open, the system controls the second valve to close less based on the pressure value fed back by the pressure sensor.

[0007] According to an embodiment of this application, the refrigerator and the evaporator constitute a refrigeration evaporation module.

[0008] According to an embodiment of this application, the pressure sensor is disposed on the pipe between the water pump and the refrigeration evaporation module.

[0009] According to an embodiment of this application, both the input and output ends of the refrigeration evaporation module are provided with flanges.

[0010] According to an embodiment of this application, the input end of the refrigeration evaporation module is connected to a first shut-off valve, and the output end of the refrigeration evaporation module is connected to a second shut-off valve.

[0011] According to an embodiment of this application, a flow switch is connected to the input terminal of the refrigeration evaporation module.

[0012] According to an embodiment of this application, the circulation loop is connected to an expansion tank.

[0013] According to an embodiment of this application, the water pump is driven by a frequency converter.

[0014] According to an embodiment of this application, the reference frequency of the water pump is set when all first valves are open and the second valves are closed.

[0015] The above scheme has at least the following beneficial effects: The water pump operates, pumping water to the chiller and evaporator. The chiller and evaporator absorb heat from the water through the refrigerant, thus cooling the water. The chilled water absorbs heat through the production line cooling equipment, cooling the equipment. The heat exchanger transfers heat to the water, further cooling it. The water flowing through the heat exchanger returns to the water pump. When the system is in operation and the load is in a cooling state, the first valves of multiple heat exchanger groups are opened to varying degrees or fully opened. When the first valve is partially closed, the system controls the second valve to open more based on the pressure value fed back by the pressure sensor; when the first valve is fully open, the system controls the second valve to close less based on the pressure value fed back by the pressure sensor. This ensures that the pressure and flow rate in the pipeline remain constant. When the amount of chilled water used by the production line decreases, the workload of the chiller decreases accordingly. Even in a zero-load shutdown state, stable water temperature and constant water pressure and flow rate can still be achieved, reaching the maximum energy saving value. Attached Figure Description

[0016] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0017] Figure 1 This is a schematic diagram of a closed-loop chilled water system provided in an embodiment of this application;

[0018] Figure 2 This is a control circuit diagram of a closed-loop chilled water circulation system provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, or the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0021] For traditional closed-loop chilled water systems, when the system is in operation and the load is in a cooling state, the E / P valves of the heat exchanger are all open to varying degrees or fully open. At this time, the pressure detected by the pressure sensors in the pipeline is between 0.2 MPa and 0.25 MPa, the flow switch flowing through the evaporator of the chiller is closed, and the temperature difference between the inlet and outlet water of the evaporator is <10℃, or even within 4℃ in the most ideal condition. Under these conditions, the system is normal. When the load is in a constant temperature or ultra-low temperature state, the E / P valves of the heat exchanger are all closed to varying degrees or even completely shut off. At this time, the pressure detected by the pressure sensors in the pipeline increases, and a feedback signal is sent to the water pump inverter. The water flow through the evaporator of the chiller decreases, which may cause the flow switch to trip, or the temperature difference between the inlet and outlet water of the evaporator may reach ≥10℃, causing the chiller to alarm and shut down, thus leading to unstable water temperature.

[0022] To address the above problems, embodiments of this application provide a closed-loop chilled water circulation system.

[0023] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0024] Reference Figure 1 and Figure 2 The chilled water closed-loop circulation system includes: a water pump 100, a chiller 200, an evaporator 300, and an exchanger 400; the water pump 100, chiller 200, evaporator 300, and exchanger 400 are connected by pipes to form a circulation loop; the pipe between the evaporator 300 and the exchanger 400 passes through the production line cooling equipment; the exchanger 400 is connected in series with the first valve 510 to form an exchanger group, and multiple exchanger groups are connected in parallel with the second valve 520; the pipes are equipped with pressure sensors 600; wherein, the system controls the opening and closing degree of the second valve 520 according to the pressure value fed back by the pressure sensor 600.

[0025] In this embodiment, the water pump 100 operates, pumping water to the chiller 200 and evaporator 300. The chiller 200 and evaporator 300 absorb heat from the water through the refrigerant, thus cooling the water. The chilled water absorbs heat through the production line cooling equipment, thus cooling the production line cooling equipment. The heat exchanger 400 transfers heat to the water, thus cooling the water. The water that has passed through the heat exchanger 400 flows back to the water pump 100.

[0026] When the system is in operation and the load is in a cooling state, the first valves 510 of multiple heat exchanger groups are opened to varying degrees or fully opened. When the first valve 510 is partially closed, the system controls the second valve 520 to open more based on the pressure value fed back by the pressure sensor 600; conversely, when the first valve 510 is fully open, the system controls the second valve 520 to close less based on the pressure value fed back by the pressure sensor 600. This ensures that the pressure and flow rate in the pipeline remain constant. When the amount of chilled water used by the production line decreases, the workload of the chiller 200 decreases accordingly. Even in a zero-load shutdown state, it can still achieve stable water temperature and constant water pressure and flow rate, reaching the maximum energy saving value.

[0027] Understandably, when the first valve 510 is partially closed, the system controls the second valve 520 to open more based on the pressure value fed back by the pressure sensor 600. This opening of the second valve 520 can indicate a change from a closed to an open state, or it can indicate a gradual increase in the degree of opening. Conversely, when the first valve 510 is fully open, the system controls the second valve 520 to close less based on the pressure value fed back by the pressure sensor 600. This closing of the second valve 520 can indicate a change from an open to a closed state, or it can indicate a gradual decrease in the degree of opening.

[0028] Specifically, both the first valve 510 and the second valve 520 are E / P valves.

[0029] There are four exchangers 400; similarly, there are four first valves 510. Of course, in other implementations, the number of exchangers 400 and first valves 510 can be set according to actual production needs.

[0030] The first exchanger 400 is a nine-line water tank exchanger 400, the second exchanger 400 is a nine-line quench roller exchanger 400, the third exchanger 400 is a ten-line water tank exchanger 400, and the fourth exchanger 400 is a ten-line quench roller exchanger 400. All four exchangers (nine-line water tank exchanger 400, nine-line quench roller exchanger 400, ten-line water tank exchanger 400, and ten-line quench roller exchanger 400) control the opening of the E / P valve according to the set temperature and the output of the temperature controller PLC (4mA to 20mA) to achieve constant temperature cooling.

[0031] The E / P valve corresponding to the nine-line quench roll exchanger 400 is marked as 1#E / P valve, the E / P valve corresponding to the nine-line quench roll exchanger 400 is marked as 2#E / P valve, the E / P valve corresponding to the ten-line water tank exchanger 400 is marked as 3#E / P valve, the E / P valve corresponding to the ten-line quench roll exchanger 400 is marked as 4#E / P valve, and the E / P valves connected in parallel are marked as 5#E / P valve.

[0032] The refrigeration unit 200 and the evaporator 300 constitute a refrigeration evaporation module. In this embodiment, there are four refrigeration evaporation modules. Of course, in other embodiments, the number of refrigeration evaporation modules can be set according to actual production needs.

[0033] The refrigeration unit 200 operates under the condition that the condenser and evaporator 300 must meet the required water flow rate, and will alarm and shut down when the inlet and outlet water temperature difference is ≥10℃. A flow switch 910 is connected to the input terminal of the refrigeration evaporation module. The flow switch 910 controls the water flow rate input to the refrigeration evaporation module. The system is equipped with an electronic device, marked S, to detect the flow rate of the evaporator 300; the water flow rate and pressure will cause the normally open contact of device S to close, thus meeting the start-up conditions. In actual operation, the water pressure is generally between 0.2 MPa and 0.25 MPa, and the water flow rate is above 100 mL / min.

[0034] A pressure sensor 600 is installed on the pipeline between the water pump 100 and the refrigeration evaporation module. The pressure sensor 600 monitors the pressure value of the pipeline. When the system is in operation and the load is in a cooling state, the first valves 510 of multiple heat exchanger groups are opened to varying degrees or fully opened. When the first valve 510 is partially closed, the system controls the second valve 520 to open further based on the pressure value fed back by the pressure sensor 600; conversely, when the first valve 510 is fully open, the system controls the second valve 520 to close less further based on the pressure value fed back by the pressure sensor 600.

[0035] Both the input and output ends of the refrigeration evaporation module are equipped with flanges of 700.

[0036] The input end of the refrigeration evaporator module is connected to the first shut-off valve 810, and the output end is connected to the second shut-off valve 820. The shut-off valves control the refrigerant flow through the refrigeration evaporator module by adjusting their opening degree, thereby affecting the system's cooling effect. Adjusting the opening degree of the shut-off valves controls the refrigerant flow into the refrigeration evaporator module, thus regulating the system's operating state. During system startup or shutdown, the shut-off valves effectively cut off the refrigerant flow, preventing liquid refrigerant from entering the compressor, avoiding liquid slugging, and protecting the compressor and other system components from damage.

[0037] The circulation loop is connected to the expansion tank 920. The expansion tank 920 is installed at the highest point and serves to release air and replenish water.

[0038] Water pump 100 is driven by a frequency converter. The reference frequency of water pump 100 is set when all first valves 510 are open and second valves 520 are closed. That is, the reference frequency of water pump 100 is set when the E / P valves corresponding to the nine-line water tank exchanger 400, the nine-line quench roller exchanger 400, the ten-line water tank exchanger 400, and the ten-line quench roller exchanger 400 are open and the 5# E / P valve is closed. The water pressure is 0.25 MPa.

[0039] The above is a detailed description of the preferred embodiments of this application, but this application is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A closed-loop chilled water system, characterized in that, include: The system includes a water pump, a chiller, an evaporator, and an exchanger; the water pump, the chiller, the evaporator, and the exchanger are connected by pipes to form a circulation loop; the pipe between the evaporator and the exchanger passes through a production line cooling device; the exchanger is connected in series with a first valve to form an exchanger group, and multiple exchanger groups are connected in parallel with a second valve; the pipes are equipped with pressure sensors; wherein, the system controls the opening and closing degree of the second valve based on the pressure value fed back by the pressure sensor.

2. The chilled water closed-loop circulation system according to claim 1, characterized in that, When the first valve is closed slightly, the system controls the second valve to open wider based on the pressure value fed back by the pressure sensor; when the first valve is opened wider, the system controls the second valve to close slightly based on the pressure value fed back by the pressure sensor.

3. The chilled water closed-loop circulation system according to claim 1, characterized in that, The refrigerator and the evaporator together form a refrigeration evaporation module.

4. The chilled water closed-loop circulation system according to claim 3, characterized in that, The pressure sensor is installed on the pipe between the water pump and the refrigeration evaporation module.

5. The chilled water closed-loop circulation system according to claim 3, characterized in that, Flanges are provided at both the input and output ends of the refrigeration evaporation module.

6. The chilled water closed-loop circulation system according to claim 3, characterized in that, The input end of the refrigeration evaporation module is connected to the first shut-off valve, and the output end of the refrigeration evaporation module is connected to the second shut-off valve.

7. The chilled water closed-loop circulation system according to claim 3, characterized in that, A flow switch is connected to the input end of the refrigeration evaporation module.

8. The chilled water closed-loop circulation system according to claim 1, characterized in that, The circulation loop is connected to the expansion tank.

9. The chilled water closed-loop circulation system according to claim 1, characterized in that, The water pump is driven by a frequency converter.

10. The chilled water closed-loop circulation system according to claim 9, characterized in that, The reference frequency of the water pump is set when all the first valves are open and the second valves are closed.

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