Chilled water control system and control method

Abstract

The application discloses a chilled water control system and a control method, and relates to the field of chilled water control systems, and aims to improve the overall operation energy efficiency of the chilled water system.

Description

Technical Field

[0001] This invention relates to the field of automatic monitoring and energy efficiency improvement of water-cooled centralized air conditioning systems, specifically to a chilled water control system and control method. Background Technology

[0002] In a conventional single-stage pump variable flow water-cooled centralized air conditioning chilled water system (hereinafter referred to as "the system"), there are two connection methods between the chiller unit and the chilled water pump: "series first, then parallel" and "parallel first, then series." The air conditioning system operates under partial load for most of its operating time. With the "series first, then parallel" connection, the pumps often operate outside their high-efficiency range, resulting in low operating efficiency and hindering energy conservation. With the "parallel first, then series" connection, the pump set can adjust the number of pumps in operation and the pump operating frequency according to the terminal load demand, reducing the overall energy consumption of the chilled water pump set and promoting energy conservation.

[0003] In conventional systems, chiller units are available in three configurations: fully fixed-frequency, fixed-frequency + variable-frequency, and fully variable-frequency. Since air conditioning systems operate under partial load most of the time, the energy efficiency of fully fixed-frequency chiller units is significantly lower than that of variable-frequency units due to their internal working principle, which is detrimental to energy conservation.

[0004] In conventional systems, chilled water pumps can be configured using either variable frequency or fixed frequency pumps. Since air conditioning systems operate under partial load most of the time, fixed frequency pumps can only control the number of pumps based on changes in terminal flow demand, but cannot adjust the pump frequency, which is not conducive to energy saving during pump operation.

[0005] In conventional systems, static balancing valves or self-regulating differential pressure balancing valves are installed on the fan coil unit loop branches and combined air conditioning terminals. Water pumps typically employ differential pressure control between the supply and return main pipes, differential pressure control in the most unfavorable loop, and constant temperature difference control between main pipes (with constant temperature difference control valves installed on different zone loops). These two types of balancing valves not only increase the resistance of the chilled water piping system, but their matching control logic also fails to maximize the chilled water outlet temperature of the chiller unit and reduce the operating frequency of the chilled water pumps while ensuring indoor comfort, thus failing to maximize the overall energy efficiency of the chilled water system.

[0006] Therefore, it is very important to develop a monitoring system and control method that is reasonable, structurally complete, effectively controlled, and can maximize the efficient operation of the entire chilled water system. Summary of the Invention

[0007] The technical problem to be solved by the present invention is that the existing single-stage pump variable flow water-cooled centralized air conditioning chilled water system has high energy consumption.

[0008] The first objective of this invention is to provide a chilled water control system, comprising an automatic control system and a chilled water pump module, a chiller unit module, and a fan module connected in sequence; the fan module includes at least two air conditioning terminal loops arranged in parallel, and the air conditioning terminal loops include a fan coil unit module and a combined air conditioning unit module;

[0009] The automatic control system includes a valve position temperature difference monitor, a chiller unit booster / subtractor monitor, a chiller unit flow monitor, an energy consumption monitor, a chilled water pump monitor, and a chilled water system logic controller.

[0010] Among them, the valve position temperature difference monitor is used to monitor in real time the valve position and supply and return water temperature difference of the local electric regulating valves on all fan coil loops with the most unfavorable hydraulic or thermal conditions, as well as on all combined air conditioning units, and to re-set the temperature difference of the remote electric regulating valves on the fan coil loops.

[0011] The chiller unit booster / minimum controller is used to acquire real-time operating parameters of the chiller unit module. It transmits the chilled water supply and return pressure difference and temperature, cooling water inlet and outlet temperatures, chiller power consumption, and outdoor wet-bulb temperature of the chiller unit module to the chilled water system logic controller. The result of the chilled water system logic controller is then used as the input of the chiller unit booster / minimum controller to perform booster / minimum controller control on the chiller units in the chiller unit module.

[0012] The chiller unit flow monitor is used to obtain the valve position of the remote electric regulating valve on the outlet pipe of the chiller unit module and the inlet and outlet temperatures of the chilled water. The result of the calculation by the chilled water system logic controller is used as the input of the chiller unit flow monitor to adjust the valve position of the electric regulating valve on the outlet pipe of the chiller unit module.

[0013] The energy consumption monitor is used to acquire the energy consumption of the chilled water pump module and the chiller module, and transmit the energy consumption to the chilled water system logic controller.

[0014] The chilled water pump monitor is used to acquire the real-time flow rate, real-time water pressure, real-time power consumption and real-time operating frequency of the chilled water pump module and transmit them to the chilled water system logic controller. It also receives instructions from the chilled water system logic controller to control the number of chilled water pumps in operation and their operating frequency in the chilled water pump module.

[0015] The chilled water system logic controller issues commands to start and stop the system, performs logical analysis on data from valve position temperature difference monitors, chiller unit booster / subtractor monitors, chiller unit flow monitors, energy consumption monitors, and chilled water pump monitors, and sends control commands to each monitor based on the analysis results.

[0016] As one possible design, the fan coil module includes at least two fan coil units connected in parallel. The control valve of the fan coil unit in each fan coil module that is hydraulically or thermally most unfavorable is a local electric regulating valve, and the control valves of the other fan coil units in the fan coil module are locally controlled electric two-position regulating valves. A remote electric regulating valve and a first temperature sensor are installed on the horizontal return water branch of the fan coil loop, and a manual shut-off valve and a second temperature sensor are installed on the horizontal supply water branch of the fan coil loop.

[0017] As one possible design, the combined air conditioning unit module includes at least two combined air conditioning units connected in parallel. The control valve on the water outlet pipe of the combined air conditioning unit is a local electric regulating valve and a third temperature sensor, and the water inlet pipe of the combined air conditioning unit is equipped with a manual shut-off valve and a fourth temperature sensor.

[0018] As one possible design, the chiller unit module includes at least two chiller units connected in parallel. Each chiller unit is equipped with a cooling water inlet pipe, a cooling water outlet pipe, a chilled water inlet pipe, and a chilled water outlet pipe. A fifth temperature sensor and a first pressure sensor are installed on the chilled water inlet pipe and the chilled water outlet pipe. A sixth temperature sensor is installed on the cooling water inlet pipe and the cooling water outlet pipe. A remote electric regulating valve is installed on the chilled water outlet pipe.

[0019] As one possible design, the chilled water pump module includes at least two chilled water pumps connected in parallel, each of which has a second pressure sensor installed on its inlet and outlet pipes, and each of which has a flow sensor installed on its inlet or outlet pipe.

[0020] As one possible design, a self-regulating differential pressure bypass valve assembly is installed between the manifolds.

[0021] As one possible design, the chilled water pumps in the chilled water pump module may have the same or different capacities, and the high-efficiency range of all chilled water pumps covers the entire flow range required for operation.

[0022] As one possible design, the chiller unit in the chiller unit module adopts a fully variable frequency mode, or a combination of variable frequency and fixed frequency mode.

[0023] A second objective of this invention is to provide a control method for the aforementioned chilled water control system, the control method comprising:

[0024] S1. Start the chilled water system logic controller. The chiller unit flow monitor issues a command to open the valve on the preset chiller unit inlet pipe and close the valve on the non-preset chiller unit inlet pipe.

[0025] S2. The valve position temperature difference monitor sets the return air temperature of the fan coil module, and the chilled water pump monitor commands to start the chilled water pump corresponding to the preset chiller unit, which operates at the industrial frequency.

[0026] S3. Start the preset chiller unit and set the outlet water temperature. Based on the goal of optimizing the energy efficiency of multiple chiller units, allocate the chilled water flow.

[0027] S4. Valve position temperature difference monitor detects valve position, return air temperature and indoor temperature status; chiller unit load / reduction monitor detects chiller unit load rate and inlet / outlet water temperature.

[0028] S5. The chilled water system logic controller determines whether it is necessary to add or remove chiller units. If it is necessary to reduce the number of chiller units, it closes the preset chiller units, delays the closure of the valves and chilled water pumps associated with those chiller units, and closes their associated valves.

[0029] S6. The valve position temperature difference monitor sets the return air temperature of the fan coil module, and the chilled water pump monitor commands to start the chilled water pump corresponding to the preset chiller unit, which operates at the industrial frequency.

[0030] S7. Start the preset chiller unit and set the outlet water temperature. Based on the goal of optimizing the energy efficiency of multiple chiller units, allocate the chilled water flow.

[0031] S8. Valve position temperature difference monitor detects valve position, return air temperature and indoor temperature status; chiller unit load / reduction monitor detects chiller unit load rate and inlet / outlet water temperature.

[0032] If there is no need to reduce the number of chiller units, the valve position temperature difference monitor detects the valve position, return air temperature and indoor temperature status, and the chiller unit load / reduction monitor detects the chiller unit load rate and inlet / outlet water temperature.

[0033] If it is necessary to increase the number of chiller units, execute S1;

[0034] S9. The chilled water system logic controller determines whether it is necessary to increase the outlet water temperature of the chilled water pump. If so, the chiller unit booster / minimum controller issues a command to increase the temperature of the chiller unit's water supply, and then executes: whether it is necessary to increase the outlet water temperature of the chilled water pump until it is no longer necessary to increase the outlet water temperature of the chilled water pump.

[0035] S10. Then lower the cooling water supply temperature of the cooling water unit;

[0036] S11. Valve position temperature difference monitor detects valve position, return air temperature and indoor temperature status; chiller unit load / reduction monitor detects chiller unit load rate and inlet / outlet water temperature.

[0037] S12. Check if the water supply temperature of the chiller unit meets the standard. If it does not meet the standard, return to step S10 until it meets the standard. Then calculate the return air temperature value of the fan coil module and set the return air temperature of the fan coil module.

[0038] S13. Calculate whether the chilled water pump can be unloaded. If so, reduce the frequency of the chilled water pump synchronously until unloading is no longer required.

[0039] S14. Control valve position temperature difference monitor, chiller unit booster / subtractor monitor, and chilled water pump monitor;

[0040] S15. The chilled water system logic controller determines whether it is necessary to add or remove chilled water units. If not, it returns to step S14. If it is necessary to reduce, it returns to step S5. If it is necessary to add, it returns to step S1.

[0041] As one possible design, the return air temperature setting of the fan coil module is 5-10℃, the outlet water temperature setting of the chiller unit is 7-12℃, the temperature increase range of the chiller unit in a single operation is 0.5-1.5℃, the temperature decrease range of the chiller unit in a single operation is 0.2-1.0℃, and the frequency of the chilled water pump in a single operation is 1-3Hz.

[0042] The beneficial effects of this invention are as follows:

[0043] This invention proposes a complete hardware and software architecture for a chilled water system, which maximizes the heat exchange capacity of the air conditioning terminal, increases the outlet temperature of the chilled water as much as possible, and reduces the operating frequency of the chilled water pump, thereby further improving the overall operating energy efficiency of the entire chilled water system. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0045] Figure 1 This is a process flow diagram of the chilled water control system in an embodiment of the present invention;

[0046] Figure 2 This is a control flowchart of the chilled water control method in an embodiment of the present invention.

[0047] The attached diagram shows the markings and corresponding component names:

[0048] 01-Fan coil unit, 02-Fan coil unit control panel, 03-Combined air conditioning unit, 04-Combined air conditioning unit control cabinet, 05-Water distributor, 06-Water collector, 07-Large capacity chiller unit, 08-Small capacity chiller unit, 09-Chiller water pump corresponding to large capacity chiller unit, 10-Chiller water pump corresponding to small capacity chiller unit, 11-High-level expansion tank, 12-Valve position temperature difference monitor, 13-Chiller unit load / reduction monitor, 14-Chiller unit flow monitor, 15-Energy consumption monitor, 16-Chiller water pump monitor, 17-Chiller water system logic controller. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0050] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0052] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] Because existing chilled water control systems still need further improvement in energy efficiency, therefore... Figure 1 As shown, an embodiment of the present invention discloses a chilled water control system, including an automatic control system and a chilled water pump module, a chiller unit module, and a fan module connected in sequence; the fan module includes at least two air conditioning terminal loops arranged in parallel, the air conditioning terminal loops include a fan coil module and a combined air conditioning unit module, the fan coil module includes a plurality of fan coil units 01, and the combined air conditioning unit module includes a plurality of fan coil units 03.

[0055] The automatic control system includes a valve position temperature difference monitor 12, a chiller unit booster / subtractor monitor 13, a chiller unit flow monitor 14, an energy consumption monitor 15, a chilled water pump monitor 16, and a chilled water system logic controller 17.

[0056] Among them, the valve position temperature difference monitor 12 is used to monitor in real time the valve position and supply and return water temperature difference of the local electric regulating valves on all fan coil loops with the most unfavorable hydraulic or thermal conditions and all combined air conditioning units, as well as to reset the temperature difference of the remote electric regulating valves on the fan coil loops.

[0057] The chiller unit booster / minimum controller 13 is used to acquire the real-time operating parameters of the chiller unit module, and transmits the chilled water supply and return water pressure difference and temperature, cooling water inlet and outlet water temperatures and outdoor wet bulb temperature of the chiller unit module to the chilled water system logic controller 17. The result of the calculation by the chilled water system logic controller 17 is then used as the input of the chiller unit booster / minimum controller 13 to perform booster / minimum controller control on the chiller unit in the chiller unit module.

[0058] The chiller unit flow monitor 14 is used to obtain the valve position of the remote electric regulating valve on the outlet pipe of the chiller unit module and the inlet and outlet temperatures of the chilled water. The result of the calculation by the chilled water system logic controller 17 is used as the input of the chiller unit flow monitor 14 to adjust the valve position of the electric regulating valve on the outlet pipe of the chiller unit module.

[0059] The energy consumption monitor 15 is used to acquire the energy consumption of the chilled water pump module and the chiller module, and transmits the energy consumption to the chilled water system logic controller 17.

[0060] The chilled water pump monitor 16 is used to acquire the real-time flow rate, real-time water pressure, real-time power consumption and real-time operating frequency of the chilled water pump module and transmit them to the chilled water system logic controller 17, and receive the instructions issued by the chilled water system logic controller 17 to control the number of chilled water pumps in operation and the operating frequency in the chilled water pump module.

[0061] The chilled water system logic controller 17 issues commands to start and stop the system, performs logical analysis on the data from the valve position temperature difference monitor 12, the chiller unit booster / subtractor monitor 13, the chiller unit flow monitor 14, the energy consumption monitor 15, and the chilled water pump monitor 16, and issues control commands to each monitor based on the analysis results.

[0062] The fan coil unit 01 module includes at least two fan coil units 01 connected in parallel. The control valve of the outlet pipe at the end of the fan coil unit 01 through which the chilled water flows is a local electric regulating valve, and the outlet pipes of the other fan coil units 01 are equipped with remote electric regulating valves and a first temperature sensor. The inlet pipe of the fan coil unit 01 is equipped with a manual shut-off valve and a second temperature sensor.

[0063] The local electric regulating valve, the remote electric regulating valve, the first temperature sensor, and the second temperature sensor are all connected to the valve position temperature difference monitor 12.

[0064] The modular air conditioning unit 03 module includes at least two modular air conditioning units 03 connected in parallel. The control valve on the water outlet pipe of the modular air conditioning unit 03 is a local electric regulating valve and a third temperature sensor. The water inlet pipe of the modular air conditioning unit 03 is equipped with a manual shut-off valve and a fourth temperature sensor.

[0065] The local electric regulating valve, the third temperature sensor, and the fourth temperature sensor are all connected to the valve position temperature difference monitor 12.

[0066] The chiller unit module includes at least two chiller units connected in parallel. Each chiller unit is equipped with a cooling water inlet pipe, a cooling water outlet pipe, a chilled water inlet pipe, and a chilled water outlet pipe. A fifth temperature sensor and a first pressure sensor are installed on the chilled water inlet pipe and the chilled water outlet pipe. A sixth temperature sensor is installed on the cooling water inlet pipe and the cooling water outlet pipe. A remote electric regulating valve is installed on the chilled water outlet pipe.

[0067] The fifth temperature sensor, the first pressure sensor, and the sixth temperature sensor are all connected to the chiller unit booster / minimum regulator 13, and the remote electric regulating valve is connected to the chiller unit flow monitor 14.

[0068] The chilled water pump module includes at least two chilled water pumps connected in parallel. Each chilled water pump has a second pressure sensor installed on its inlet and outlet pipes, and each chilled water pump has a flow sensor installed on its inlet and / or outlet pipes.

[0069] The second pressure sensor and flow sensor are simultaneously connected to the chiller unit booster / reducer monitor 13, the energy consumption monitor 15, and the chilled water pump monitor 16.

[0070] To prevent the chilled water pump from clogging, a filter is installed at the inlet of the chilled water pump. Specifically, the filter can be a Y-type filter. In order to monitor whether the filter is working properly, a third pressure sensor is installed at one end of the filter. The third pressure sensor is also connected to the chiller unit booster / reducer monitor 13, the energy consumption monitor 15, and the chilled water pump monitor 16.

[0071] To further save energy, the maximum flow rates of the chilled water pumps connected in parallel do not need to be exactly the same, but the high-efficiency zone of the combined pumps formed by these chilled water pumps needs to cover the entire flow range of the chilled water system. During operation, the pumps can operate in their high-efficiency zone in real time according to the load demand of the air conditioning terminals, providing chilled water flow on demand to achieve energy savings in chilled water pump operation.

[0072] To further save energy, chiller units connected in parallel can adopt a full variable frequency mode or a combination of variable frequency and fixed frequency modes. The specific choice depends on the actual load requirements of the chilled water system and outdoor weather conditions.

[0073] The chilled water pump 09 corresponding to the large-capacity chiller supplies water to the large-capacity chiller 07, and the chilled water pump 10 corresponding to the small-capacity chiller supplies water to the small-capacity chiller 08.

[0074] In order to disconnect a faulty chilled water pump without affecting the system's water supply, a self-operated differential pressure bypass valve is installed next to each chilled water pump. The inlet and outlet pipes of the self-operated differential pressure bypass valve are connected to the inlet and outlet pipes of the chilled water pump, respectively.

[0075] To prevent chilled water from flowing back into the chilled water pump, a check valve is installed on the outlet pipe of the chilled water pump.

[0076] In order to ensure that water can stably enter the chilled water pump and recover water from the fan coil unit 01 and the combined air conditioning unit 03, the chilled water control system also includes a water collector 06. The water collector 06 is provided with two inlet ends, one of which is connected to the water outlet pipe of the combined air conditioning unit 03 and the fan coil unit 01, and the other inlet end is connected to the high-level expansion tank 11. The water collector 06 is provided with a water outlet end, which is connected to the water inlet end of the chilled water pump.

[0077] The water outlet pipe of the chiller unit is connected to a water distributor 05, which has multiple water outlet pipes. The number of water outlet pipes is the same as the number of fan modules.

[0078] When the fan module malfunctions or stops operating, the water distributor 05 and the water collector 06 are connected, and multiple valves can be installed on the connected pipeline.

[0079] Each fan coil unit 01 is equipped with a fan coil unit control panel 02. The fan coil unit control panel 02 is communicatively connected to the remote electric valve and the local control valve. The information output terminal of the fan coil unit control panel 02 is communicatively connected to the valve position temperature difference monitor 12. Each combined air conditioning unit 03 is equipped with a combined air conditioning unit control cabinet 04. The combined air conditioning unit control cabinet 04 is communicatively connected to the local control valve of the combined air conditioning unit 03. The information output terminal of the combined air conditioning unit control cabinet 04 is communicatively connected to the valve position temperature difference monitor 12.

[0080] like Figure 2 As shown, the control logic of the chilled water control system is as follows:

[0081] When the chilled water control system needs to be turned on, the chilled water control system is started with one button. The chilled water system logic controller 17 sends commands to the chiller flow monitor, valve position temperature difference monitor 12, chilled water pump monitor 16, chiller load / reduction monitor, and chiller flow monitor.

[0082] The specific control logic of the control system is as follows: Open the electric valve at the inlet of the preset chiller unit, and close the electric valve at the inlet of the non-preset chiller unit → Set the return air temperature of the temperature difference control valve of the fan coil unit 01 branch water loop to 5℃ → Start the chilled water pump corresponding to the preset chiller unit and run it at industrial frequency → Confirm that the cooling water pump and cooling tower corresponding to the preset chiller unit are operating normally → Start the preset chiller unit and set the outlet water temperature to 7℃ → Distribute the chilled water flow based on the goal of optimizing the energy efficiency of multiple chillers.

[0083] Once the system is running stably, the chilled water system logic controller 17 uses the valve position, temperature difference, and indoor temperature status of the electric regulating valve monitored by the valve position temperature difference monitor 12, as well as the load rate of the chillers and the inlet and outlet water temperatures monitored by the chiller addition / reduction monitor, to determine whether the number of chillers needs to be increased or decreased. When it is necessary to add chillers, the previously executed process is repeated. When it is necessary to reduce the number of chillers, the relevant commands are executed in sequence: shut down the preset chiller → delay the shutdown of the chiller inlet electric valve and the corresponding cooling tower, cooling water pump, and cooling water system valves → set the return air temperature of the fan coil unit 01 branch pipe water loop temperature difference control valve to 5℃ → set the outlet water temperature of the running chiller to 7℃ → allocate the chilled water flow based on the goal of optimal energy efficiency of multiple chillers. After the system stabilizes, the chilled water system logic controller 17 determines whether the chilled water temperature can be increased based on the valve position, temperature difference, and indoor temperature status of the electric regulating valve monitored by the valve position temperature difference monitor 12. If it can be increased, the temperature is increased by 1°C; if not, it is decreased by 0.5°C, until the chilled water outlet temperature meets the requirements. After the chilled water temperature increase process is completed, the chilled water system logic controller 17 calculates and the valve position temperature difference monitor 12 re-sets the temperature difference of the remote electric regulating valve on the fan coil unit 01 branch pipe. Finally, the chilled water system logic controller 17 calculates and the chilled water pump controller reduces the frequency of the chilled water pump to achieve the energy-saving operating point of the pump. When the energy consumption of the chilled water system changes, the chilled water system logic controller 17 performs logical calculations: when it is necessary to add or remove chiller units, the previously executed process is repeated; when it is not necessary to add or remove chiller units, the chilled water system logic controller 17 controls the valve position temperature difference monitor 12, the chilled water pump monitor 16, and the chiller addition / reduction monitor to maintain efficient system operation.

[0084] The return air temperature refers to the temperature difference between the inlet water temperature and the outlet water temperature.

[0085] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method based on a chilled water control system, characterized in that, The chilled water control system includes an automatic control system and a chilled water pump module, a chiller unit module, and a fan module connected in sequence; the fan module includes at least two air conditioning terminal loops arranged in parallel, and the air conditioning terminal loops include a fan coil module and a combined air conditioning unit module; The automatic control system includes a valve position temperature difference monitor, a chiller unit booster / subtractor monitor, a chiller unit flow monitor, an energy consumption monitor, a chilled water pump monitor, and a chilled water system logic controller. Among them, the valve position temperature difference monitor is used to monitor in real time the valve position and supply and return water temperature difference of the local electric regulating valves on all fan coil loops with the most unfavorable hydraulic or thermal conditions, as well as on all combined air conditioning units, and to re-set the temperature difference of the remote electric regulating valves on the fan coil loops. The chiller unit booster / minimum controller is used to acquire real-time operating parameters of the chiller unit module. It transmits the chilled water supply and return pressure difference and temperature, cooling water inlet and outlet temperatures, chiller power consumption, and outdoor wet-bulb temperature of the chiller unit module to the chilled water system logic controller. The result of the chilled water system logic controller is then used as the input of the chiller unit booster / minimum controller to perform booster / minimum controller control on the chiller units in the chiller unit module. The chiller unit flow monitor is used to obtain the valve position of the remote electric regulating valve on the outlet pipe of the chiller unit module and the inlet and outlet temperatures of the chilled water. The result of the calculation by the chilled water system logic controller is used as the input of the chiller unit flow monitor to adjust the valve position of the electric regulating valve on the outlet pipe of the chiller unit module. The energy consumption monitor is used to acquire the energy consumption of the chilled water pump module and the chiller module, and transmits the energy consumption to the chilled water system logic controller. The chilled water pump monitor is used to acquire the real-time flow rate, real-time water pressure, real-time power consumption and real-time operating frequency of the chilled water pump module and transmit them to the chilled water system logic controller. It also receives instructions from the chilled water system logic controller to control the number of chilled water pumps in operation and their operating frequency in the chilled water pump module. Control methods include: S1. Start the chilled water system logic controller, and the chiller unit flow monitor sends a command to open the valve on the preset chiller unit inlet pipe and close the valve on the non-preset chiller unit inlet pipe; S2. The valve position temperature difference monitor sets the return air temperature of the fan coil module, and the chilled water pump monitor commands to start the chilled water pump corresponding to the preset chiller unit, which operates at the industrial frequency. S3. Start the preset chiller unit and set the outlet water temperature. Based on the goal of optimizing the energy efficiency of multiple chiller units, allocate the chilled water flow. S4. Valve position temperature difference monitor detects valve position, return air temperature and indoor temperature status; chiller unit load / reduction monitor detects chiller unit load rate and inlet / outlet water temperature. S5. The chilled water system logic controller determines whether it is necessary to add or remove chiller units. If it is necessary to reduce the number of chiller units, it closes the preset chiller units, delays the closure of the valves and chilled water pumps associated with those chiller units, and closes their associated valves. S6. The valve position temperature difference monitor sets the return air temperature of the fan coil module, and the chilled water pump monitor commands to start the chilled water pump corresponding to the preset chiller unit, which operates at the industrial frequency. S7. Start the preset chiller unit and set the outlet water temperature. Based on the goal of optimizing the energy efficiency of multiple chiller units, allocate the chilled water flow. S8. Valve position temperature difference monitor detects valve position, return air temperature and indoor temperature status; chiller unit load / reduction monitor detects chiller unit load rate and inlet / outlet water temperature. If there is no need to reduce the number of chiller units, the valve position temperature difference monitor detects the valve position, return air temperature and indoor temperature status, and the chiller unit load / reduction monitor detects the chiller unit load rate and inlet / outlet water temperature. If it is necessary to increase the number of chiller units, execute S1; S9. The chilled water system logic controller determines whether it is necessary to increase the outlet water temperature of the chilled water pump. If so, the chiller unit booster / minimum controller issues a command to increase the temperature of the chiller unit's water supply, and then executes: whether it is necessary to increase the outlet water temperature of the chilled water pump until it is no longer necessary to increase the outlet water temperature of the chilled water pump. S10. Then lower the cooling water supply temperature of the cooling water unit; S11. Valve position temperature difference monitor detects valve position, return air temperature and indoor temperature status; chiller unit load / reduction monitor detects chiller unit load rate and inlet / outlet water temperature. S12. Check if the water supply temperature of the chiller unit meets the standard. If it does not meet the standard, return to step S10 until it meets the standard. Then calculate the return air temperature value of the fan coil module and set the return air temperature of the fan coil module. S13. Calculate whether the chilled water pump can be unloaded. If so, reduce the frequency of the chilled water pump synchronously until unloading is no longer required. S14. Control valve position temperature difference monitor, chiller unit booster / subtractor monitor, and chilled water pump monitor; S15. The chilled water system logic controller determines whether it is necessary to add or remove chilled water units. If not, it returns to step S14. If it is necessary to reduce, it returns to step S5. If it is necessary to add, it returns to step S1.

2. The control method based on a chilled water control system according to claim 1, characterized in that, The return air temperature setting of the fan coil module is 5~10℃, the outlet water temperature setting of the chiller unit is 7~12℃, the temperature increase range of the chiller unit in a single operation is 0.5~1.5℃, the temperature decrease range of the chiller unit in a single operation is 0.2~1.0℃, and the frequency of the chilled water pump in a single operation is 1~3HZ.

3. A chilled water control system, implemented using the control method described in claim 1 or 2, characterized in that, It includes an automatic control system and a chilled water pump module, a chiller unit module, and a fan module connected in sequence; the fan module includes at least two air conditioning terminal loops arranged in parallel, and the air conditioning terminal loops include a fan coil unit module and a combined air conditioning unit module; The automatic control system includes a valve position temperature difference monitor, a chiller unit booster / subtractor monitor, a chiller unit flow monitor, an energy consumption monitor, a chilled water pump monitor, and a chilled water system logic controller. Among them, the valve position temperature difference monitor is used to monitor in real time the valve position and supply and return water temperature difference of the local electric regulating valves on all fan coil loops with the most unfavorable hydraulic or thermal conditions, as well as on all combined air conditioning units, and to re-set the temperature difference of the remote electric regulating valves on the fan coil loops. The chiller unit booster / minimum controller is used to acquire real-time operating parameters of the chiller unit module. It transmits the chilled water supply and return pressure difference and temperature, cooling water inlet and outlet temperatures, chiller power consumption, and outdoor wet-bulb temperature of the chiller unit module to the chilled water system logic controller. The result of the chilled water system logic controller is then used as the input of the chiller unit booster / minimum controller to perform booster / minimum controller control on the chiller units in the chiller unit module. The chiller unit flow monitor is used to obtain the valve position of the remote electric regulating valve on the outlet pipe of the chiller unit module and the inlet and outlet temperatures of the chilled water. The result of the calculation by the chilled water system logic controller is used as the input of the chiller unit flow monitor to adjust the valve position of the electric regulating valve on the outlet pipe of the chiller unit module. The energy consumption monitor is used to acquire the energy consumption of the chilled water pump module and the chiller module, and transmits the energy consumption to the chilled water system logic controller. The chilled water pump monitor is used to acquire the real-time flow rate, real-time water pressure, real-time power consumption and real-time operating frequency of the chilled water pump module and transmit them to the chilled water system logic controller. It also receives instructions from the chilled water system logic controller to control the number of chilled water pumps in operation and their operating frequency in the chilled water pump module. The chilled water system logic controller issues commands to start and stop the system, performs logical analysis on data from valve position temperature difference monitors, chiller unit booster / subtractor monitors, chiller unit flow monitors, energy consumption monitors, and chilled water pump monitors, and sends control commands to each monitor based on the analysis results.

4. The chilled water control system according to claim 3, characterized in that, The fan coil unit module includes at least two fan coil units connected in parallel. The control valve of the fan coil unit with the most unfavorable hydraulic or thermal conditions in each fan coil unit module is a local electric regulating valve. The control valves of the other fan coil units in the fan coil unit module are locally controlled electric two-position regulating valves. A remote electric regulating valve and a first temperature sensor are installed on the horizontal return water branch pipe of the fan coil unit loop. A manual shut-off valve and a second temperature sensor are installed on the horizontal supply water branch pipe of the fan coil unit loop.

5. The chilled water control system according to claim 3, characterized in that, The modular air conditioning unit module includes at least two modular air conditioning units connected in parallel. The control valve on the water outlet pipe of the modular air conditioning unit is a local electric regulating valve and a third temperature sensor, and the water inlet pipe of the modular air conditioning unit is equipped with a manual shut-off valve and a fourth temperature sensor.

6. The chilled water control system according to claim 3, characterized in that, The chiller unit module includes at least two chiller units connected in parallel. Each chiller unit is equipped with a cooling water inlet pipe, a cooling water outlet pipe, a chilled water inlet pipe, and a chilled water outlet pipe. A fifth temperature sensor and a first pressure sensor are installed on the chilled water inlet pipe and the chilled water outlet pipe. A sixth temperature sensor is installed on the cooling water inlet pipe and the cooling water outlet pipe. A remote electric regulating valve is installed on the chilled water outlet pipe.

7. The chilled water control system according to claim 3, characterized in that, The chilled water pump module includes at least two chilled water pumps connected in parallel. Each chilled water pump is equipped with a second pressure sensor on its inlet and outlet pipes, and a flow sensor is equipped on its inlet and / or outlet pipes.

8. The chilled water control system according to claim 7, characterized in that, A self-regulating differential pressure bypass valve group is installed between the manifolds.

9. The chilled water control system according to claim 7, characterized in that, The chilled water pumps in the chilled water pump module have different capacities, and the high-efficiency range of all chilled water pumps covers the entire flow range required for operation.

10. The chilled water control system according to claim 6, characterized in that, The chiller unit module adopts a fully variable frequency or a combination of variable frequency and fixed frequency modes.

Images