Central air conditioning system

Abstract

The utility model discloses a central air conditioning system which comprises a central air conditioner, an upper computer, a first master station module, a second slave station module, a third slave station module, a fourth slave station module, a fifth slave station module and a plurality of sixth slave station modules. The central air conditioner comprises a water chilling unit, a cooling water pump, a chilled water pump, an air conditioner tail end and a cooling tower. The utility model provides a central air-conditioning system. Load change and system control are tracked in real time through a PLC (Programmable Logic Controller), an upper computer, various sensors and a tail end controller.

Description

Technical Field

[0001] This utility model relates to the field of central air conditioning, and in particular to a central air conditioning system. Background Technology

[0002] In existing technologies, central air conditioning achieves cooling through the cooperation of chiller units, cooling water pumps, chilled water pumps, air conditioning terminals, and cooling towers, but it lacks load tracking and system control for central air conditioning. Utility Model Content

[0003] The purpose of this utility model is to provide a central air conditioning system that aims to solve the system control problem of central air conditioning systems.

[0004] Central air conditioning, host computer, master station module 1, slave station module 2, slave station module 3, slave station module 4, slave station module 5 and multiple slave station modules 6;

[0005] The central air conditioning system includes: a chiller unit, a cooling water pump, a chilled water pump, air conditioning terminals, and a cooling tower;

[0006] The chiller unit is equipped with a controller for collecting operating parameters of the chiller unit. The cooling water pump is equipped with a first collector, the chilled water pump is equipped with a second collector, the cooling tower is equipped with a third collector, and the air conditioning terminal is equipped with a fourth collector.

[0007] The cooling tower is equipped with a first frequency converter, the cooling water pump is equipped with a second frequency converter, the chilled water pump is equipped with a third frequency converter, and the air conditioning terminal is equipped with an electric control valve.

[0008] The cooling tower is equipped with a fan, and the first frequency converter is used to control the fan speed;

[0009] The second frequency converter is used to change the speed of the cooling water pump;

[0010] The third frequency converter is used to change the speed of the chilled water pump;

[0011] Electric control valves are used to control the flow rate at the air conditioning terminal.

[0012] Slave module 2 is connected to the third data collector and master module 1, respectively;

[0013] Slave module three is connected to the first data collector and master module one, respectively;

[0014] Slave module four is connected to the controller and master module one in the chiller unit, respectively;

[0015] Slave module five is connected to the second data collector and master module one, respectively;

[0016] Multiple slave modules (6) are connected to the fourth data collector and the master module (1), respectively.

[0017] The main station module 1 is connected to the host computer, the controller in the chiller unit, the first frequency converter, the second frequency converter, the third frequency converter, and the electric control valve.

[0018] This invention provides a central air conditioning system that uses a PLC, host computer, various sensors, and terminal controllers to track load changes and control the system in real time.

[0019] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, the following are specific embodiments of this utility model. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the frame structure of a central air conditioning system according to an embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram of the specific structure of a central air conditioning system according to an embodiment of the present invention.

[0023] The attached diagram is explained as follows: F: Flow sensor; T: Insertion temperature sensor; TH: Atmospheric temperature and humidity sensor; VFD: Frequency converter; M: Motor; A: Master module 1; B: Slave module 2; G: Slave module 3; K: Slave module 4; O: Slave module 5; N: Slave module 6-1-1; N1: Slave module 6-1-i; N2: Slave module 6-1-L; DW: Water distributor; CW: Water collector. Detailed Implementation

[0024] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0025] Example 1

[0026] According to an embodiment of the present invention, a central air conditioning system is provided. Figure 1 This is a schematic diagram of a central air conditioning system according to an embodiment of the present invention, as shown below. Figure 1 As shown, it specifically includes:

[0027] Central air conditioning, host computer, master station module 1, slave station module 2, slave station module 3, slave station module 4, slave station module 5 and multiple slave station modules 6;

[0028] The central air conditioning system includes: a chiller unit, a cooling water pump, a chilled water pump, air conditioning terminals, and a cooling tower;

[0029] The air conditioning terminal is equipped with an electric control valve to control the airflow.

[0030] The chiller unit is equipped with a controller for collecting operating parameters of the chiller unit. The cooling water pump is equipped with a first collector, the chilled water pump is equipped with a second collector, the cooling tower is equipped with a third collector, and the air conditioning terminal is equipped with a fourth collector.

[0031] The cooling tower is equipped with a first frequency converter, the cooling water pump is equipped with a second frequency converter, and the chilled water pump is equipped with a third frequency converter. It is the core equipment of the air conditioning system. The air conditioning terminal system is equipped with an electric control valve for water system force balance, a regulating valve for tracking load change control commonly used in traditional central air conditioning, and a balancing valve for hydraulic balance regulation.

[0032] The cooling tower is equipped with a fan. The first frequency converter is used to control the fan speed; the second frequency converter is used to change the speed of the cooling water pump; the third frequency converter is used to change the speed of the chilled water pump; the electric control valve of the terminal device group is used to control the hydraulic balance of the air conditioning terminal flow; the slave module 2 is connected to the third collector and the master module 1 respectively; the slave module 3 is connected to the first collector and the master module 1 respectively; the slave module 4 is connected to the controller in the chiller unit and the master module 1 respectively; the slave module 5 is connected to the second collector and the master module 1 respectively; and multiple slave modules 6 are connected to the fourth collector and the master module 1 respectively.

[0033] The main station module 1 is connected to the host computer, the controller in the chiller unit, the first frequency converter, the second frequency converter, and the third frequency converter.

[0034] The cooling water pump is equipped with a first collector, the chilled water pump is equipped with a second collector, the cooling tower is equipped with a third collector, and the air conditioning terminal group is equipped with a fourth collector.

[0035] In this embodiment of the utility model, the type and location of the data collector are designed as follows:

[0036] The third data acquisition device includes: an ambient temperature and humidity sensor installed outside the cooling tower, a cooling tower inlet water insertion temperature sensor, and a cooling tower outlet water insertion temperature sensor.

[0037] The first data acquisition device includes: a cooling water pump insertion temperature sensor, a first flow sensor, and a first differential pressure sensor.

[0038] The chiller unit is equipped with a dedicated DDC controller.

[0039] The second data acquisition device includes: a chilled water pump return water insertion temperature sensor, a chilled water pump supply water insertion temperature sensor, a second flow sensor, and a second inlet / outlet differential pressure sensor.

[0040] The fourth data acquisition device includes: a second flow sensor, a second differential pressure sensor, and an air conditioning terminal insertion temperature sensor.

[0041] The connection between slave module four and master module one is made using an RS485 / Profibus communication interface converter, and the connection between master module one and the host computer is made using a TCP / IP network.

[0042] The connection between slave module 2, slave module 3, slave module 5, multiple slave modules 6 and the master module 1 adopts Profibus fieldbus;

[0043] The main station module one adopts an S7400 PLC;

[0044] In this embodiment of the utility model, a Siemens S7400 PLC, SIMATIC S7-400 PLC model, is used.

[0045] The slave module 2, slave module 3, slave module 4, slave module 5 and multiple slave modules 6 adopt S7200 PLC;

[0046] In this embodiment of the utility model, a Siemens S7200 PLC, model SIMATIC S7-200 PLC, is used.

[0047] The chiller unit is equipped with a DDC controller, which interacts with the host computer through slave module four and master module one.

[0048] In this embodiment of the utility model, the air conditioning terminal equipment is installed in multiple rooms on multiple floors, and the air conditioning terminal is one of the air conditioning terminal equipment.

[0049] like Figure 2As shown: The multiple slave modules include: slave module 6-1-1, slave module 6-1-i and slave module 6-1-L, i = 2 to L-1. DW is a water distributor, used to distribute cooling water to the air conditioning terminal; CW is a water collector, used to collect the return water from the air conditioning terminal, and is a device in the central air conditioning system.

[0050] In this embodiment of the invention, the system operates as follows:

[0051] Regulating valve EV 6.1.1 Open to maximum to minimize water resistance, and collect the pressure difference Δp of the 1-1 floor operating parameters from station module 6-1-1. 6.1.1 and flow f 6.1.1 To reflect the load change information of the entire air conditioning system, the temperature t of the water outlet at the furthest terminal 1-1-a is collected. 6.1.1 And it is sent to the master station module one via the Profibus fieldbus, and the master station module one then sends the temperature sensor t via the Profibus fieldbus. 6.1.1 The signal is sent to slave module five, which then controls the system's chilled water pump to track changes in the total load of the air conditioning system in real time.

[0052] Slave module 5 receives the output temperature sensor data forwarded by master module 1 via the Profibus fieldbus. 6.1.1 The outlet water temperature, representing the overall load change of the air conditioning system, is measured. This outlet water temperature is compared with the setpoint, and a variable frequency increment, which is related to the deviation, is calculated and output. This variable frequency increment can be implemented using existing PID control. The operating frequency of the variable frequency chilled water pump is controlled via a Modbus fieldbus. Immediately afterward, the outlet of the synchronous variable frequency pump sends a pressure wave at a speed of 1500 m / s to each air conditioning terminal, changing the flow rate. This ensures that the real-time flow rate of each air conditioning terminal corresponds to its real-time load, and that the real-time flow rate of the chilled water pump corresponds to the real-time total load of the air conditioning system. Finally, the outlet water temperature of each air conditioning terminal, including the outlet temperature t, is adjusted accordingly. 6.1.1 It has returned to the fluctuation range allowed by the set value.

[0053] The process by which the slave module 5 controls the chilled water pump frequency converter via the underlying Modbus fieldbus is as follows:

[0054] The outlet water temperature of a certain air conditioning terminal returned to the set value's allowable fluctuation range, completing the control task of the chilled water pump to achieve the most energy-efficient real-time tracking of load changes. Simultaneously, slave module five acquired and recorded the operating parameters of the chilled water pump inverter and motor via the underlying Modbus fieldbus, and acquired the pressure difference Δp of each chilled water pump through the slave module five's interface. 5.1 Flow f 5.1 Return water temperature t 5.2 and water supply temperature t5.1 The system transmits the operating parameters and status of the chilled water pump, as well as the operating electrical parameters of the pump motor and frequency converter, to the master station module 1 via the Profibus fieldbus. The master station module 1 then transmits these collected physical and electrical operating parameters of the chilled water pump to the host computer via the TCP / IP computer network. At the same time, the slave station module 5 receives the control commands sent by the host computer from the master station module 1.

[0055] Slave module four is an RS485 / Profibus communication interface converter for the chiller unit. It uploads the chiller unit's operating parameters and status from the powerful DDC control of the chiller unit to master module one, and then uploads them to the host computer via TCP / IP. At the same time, it receives optimized control commands from master module one, such as the control of the number of chiller units operating to match the chiller unit's outlet water temperature setpoint and load. The real-time tracking and control of the chiller unit's load is completed by the chiller unit's DDC controller.

[0056] Slave module three collects water pump operating parameters: temperature sensor t 3.1 Collect the cooling water outlet temperature of the chiller unit; Δp 3.1 Differential pressure sensor collects water pump head; flow sensor f 3.1 The system collects the flow rate of the water pump. Slave module 3 collects the operating parameters and status of the water pump inverter and water pump motor through the underlying Modbus fieldbus, and uploads the operating parameters of the cooling water pump, its motor, and inverter to master module 1 through the fieldbus. Master module 1 then uploads the data to the host computer via TCP / IP network, and simultaneously receives control commands from the host computer issued by master module 1.

[0057] The process of controlling the chiller unit condenser in real time by the slave module 3 and the system control is as follows: Because it is a quantity-based system, when the load on the chiller unit condenser changes, it causes a change in the chiller unit's cooling water outlet temperature. This change is detected by the temperature sensor t. 3.1 The measured value sent to slave module three is related to its set value t. 3.1.0 The deviation is compared and calculated to determine the inverter deviation control variable, which has a certain functional relationship with the deviation. The control quantity can be implemented using existing PID control. Through the underlying Modbus fieldbus, the operating frequency of the synchronous variable frequency cooling water pump is changed. The pump outlet sends a command to each chiller unit to change the flow rate in the form of a 1500m / s velocity pressure wave. This makes the real-time flow rate of each chiller unit's condenser correspond to its real-time load, and the real-time flow rate of the cooling water pump corresponds to the real-time total load of each chiller unit's condenser, thus adjusting the chiller unit condenser outlet temperature t. 3.1 It has returned to the fluctuation range allowed by the set value.

[0058] The slave module collects the cooling tower operating parameters and ambient temperature and humidity parameters and sends them to the master module for monitoring. It also receives control commands from the master module, which control the frequency converter. The cooling tower operating parameters include: cooling tower inlet water temperature, cooling tower return water temperature, and motor operating parameters.

[0059] Beneficial effects: This utility model provides a central air conditioning system that uses PLC, host computer, various sensors, and terminal control to track load changes and control the system in real time.

[0060] The control of the electric control valve and frequency converter ensures that the system does not consume a large amount of pump power when the water pump is operating under full similar conditions, resulting in low energy consumption.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions to the technical solutions of the embodiments of this utility model do not cause the essence of the corresponding technical solutions to deviate from the scope of this solution.

Claims

1. A central air conditioning system, characterized by, include: Central air conditioning, host computer, master station module 1, slave station module 2, slave station module 3, slave station module 4, slave station module 5 and multiple slave station modules 6; The central air conditioning system includes: a chiller unit, a cooling water pump, a chilled water pump, air conditioning terminals, and a cooling tower. The cooling water pump is connected to the chiller unit and the cooling tower, the chiller unit is connected to the air conditioning terminals, and the air conditioning terminals are connected to the chilled water pump. The chiller unit is equipped with a controller for collecting operating parameters of the chiller unit. The cooling water pump is equipped with a first collector, the chilled water pump is equipped with a second collector, the cooling tower is equipped with a third collector, and the air conditioning terminal is equipped with a fourth collector. The cooling tower is equipped with a first frequency converter, the cooling water pump is equipped with a second frequency converter, the chilled water pump is equipped with a third frequency converter, and the air conditioning terminal is equipped with an electric control valve. The cooling tower is equipped with a fan, and the first frequency converter is used to control the fan speed; The second frequency converter is used to change the speed of the cooling water pump; The third frequency converter is used to change the speed of the chilled water pump; Electric control valves are used to control the flow rate at the air conditioning terminal. Slave module 2 is connected to the third data collector and master module 1, respectively; Slave module three is connected to the first data collector and master module one, respectively; Slave module four is connected to the controller and master module one in the chiller unit, respectively; Slave module five is connected to the second data collector and master module one, respectively; Multiple slave modules (6) are connected to the fourth data collector and the master module (1), respectively. The main station module 1 is connected to the host computer, the controller in the chiller unit, the first frequency converter, the second frequency converter, the third frequency converter, and the electric control valve.

2. The system according to claim 1, characterized in that, The third data acquisition device includes: an ambient temperature and humidity sensor installed outside the cooling tower, a cooling tower inlet water insertion temperature sensor, and a cooling tower outlet water insertion temperature sensor.

3. The system of claim 1, wherein, The first data acquisition device includes: a cooling water pump insertion temperature sensor, a first flow sensor, and a first differential pressure sensor.

4. The system of claim 1, wherein, The chiller unit is equipped with a DDC controller.

5. The system of claim 1, wherein, The second data acquisition device includes: a chilled water pump return water insertion temperature sensor, a chilled water pump supply water insertion temperature sensor, a second flow sensor, and a second inlet / outlet differential pressure sensor.

6. The system of claim 1, wherein, The fourth data acquisition device includes: a second flow sensor, a second differential pressure sensor, and an air conditioning terminal insertion temperature sensor.

7. The system of claim 1, wherein, The connection between slave module four and master module one is achieved using an RS485 / Profibus communication interface converter.

8. The system of claim 1, wherein, The connection between the main station module and the host computer is via a TCP / IP network.

9. The system according to claim 1, characterized in that, The connection between slave module 2 and master module 1 uses a Profibus bus; the connection between slave module 3 and master module 1 uses a Profibus bus; the connection between slave module 5 and master module 1 uses a Profibus bus; and the connection between the multiple slave modules 6 and master module 1 uses a Profibus bus.

10. The system of claim 1, wherein, The master station module one uses an S7400 PLC, and the slave station modules two, three, four, five and multiple slave station modules six use an S7200 PLC.

Images