Cooling-water machine system

Abstract

The invention discloses a water chiller system which aims at achieving the purposes that tripping of a water chiller unit system in the starting process can be monitored in real time, and the water inlet temperature of a condenser can be controlled. A water chiller system comprises an MGMCOTAI water chiller unit, a heat pump system, a refrigerator and a water chiller unit control system. A dynamic water pump rotating speed control method is adopted in the starting process of the water chilling unit, and tripping of a water chilling unit system in the starting process is prevented. The developed system adopts remote monitoring and EMS (Energy Management System) design. Performance evaluation is conducted on the water chilling unit regularly, and data are collected for preventive maintenance. The multiple water chilling units are lifted in a segmented mode, the water inlet temperature of the condenser is controlled, and the energy-saving effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of chiller system control, and in particular to a chiller system. Background Art

[0002] In recent years, with the continuous innovation and development of the HVAC industry, evaporative cooling chiller systems using evaporative cooling technology have been used in many projects. The existing chiller systems have the following problems:

[0003] Since the chiller system usually has multiple chillers, when the chillers are running at the same time, the power consumption is often high, which seriously affects the performance of the whole machine. Currently, there are few fully automatic control systems on the market, and there are many technical obstacles in the system design, such as no water pump bypass and no chilled water header bypass.

[0004] The control method of the existing chiller's refrigeration throttling component is mainly to control the return air superheat to achieve the normal operation of the unit. The return air superheat consists of two parts, namely the return air pressure and the return air temperature. The refrigeration throttling component adjusts the return air superheat by opening or closing. However, the return air pressure and return air temperature may change at the same time due to the opening and closing of the refrigeration throttling component, and the return air superheat becomes uncontrollable. How to make the chiller system stable and controllable, reduce system fluctuations, and ensure capacity, energy efficiency and reliability has become an urgent problem to be solved. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a chiller system, improve the system performance of the chiller system and solve the problem of monitoring the tripping of the chiller system during startup and controlling the condenser inlet water temperature.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A chiller system comprises an MGMCOTAI chiller, a heat pump system, a refrigerator and a chiller control system.

[0008] Furthermore, the MGM COTAI chiller consists of three 4000RT chillers and two 7.5MW heat pump units.

[0009] Furthermore, the heat pump system provides 60°C heat pump hot water supply to the use site and produces 5.6°C chilled water at the same time.

[0010] Furthermore, the refrigerator is composed of 2000RT×2 units in series in a countercurrent structure.

[0011] Furthermore, the chiller control system consists of two parts: hardware design and software design. The PLC control system of the hardware design is designed for signal I / O and independent operation. The PLC control system is connected to the MGM company network, and all data in the PLC control system can be monitored in the network through a PC. The software design is a special control software developed for MGM. The MGM control system has 2 control software: monitoring software and optimal control software.

[0012] Furthermore, the software design includes a data flow unit in the control system, and the control system sends the shared memory to any PC in the MGM company network through Modbus communication. Each PC in the MGM company network can access the shared memory data of the control PC and display the operating data in real time. The shared memory stores all the operating data of the chiller system, the optimization control calculation results and the chiller performance evaluation results.

[0013] Furthermore, the performance monitoring unit in the software design monitors the performance of the chiller and the heat pump.

[0014] Furthermore, the common main system unit in the software design is installed with a flow control valve and a flow meter, and the control system is used to determine whether the differential pressure and water pump speed of the chiller are abnormal and control them when the chiller is started. The control system is used to check the header pressure and control the pump speed to keep the header pressure constant to achieve the control effect when the pump is started. The control system is used to check the header pressure and control the pump speed to keep the header pressure constant to achieve the effect of controlling the pump to stop.

[0015] Furthermore, the energy management system unit in the software design records the loads of chilled water and hot water for the functions of operating effect analysis and power consumption breakdown.

[0016] Furthermore, the operating unit in the PLC in the software design enables the chiller system to operate in PLC mode when a PC fails.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The design of the present invention puts the MGM chiller system in full automatic control / operation state. The dynamic water pump speed control method is used during the chiller startup process to prevent the chiller system from tripping during startup. The developed system adopts remote monitoring and EMS (energy management system) design. The performance of the chiller is evaluated regularly and data is collected for preventive maintenance. Multiple chillers are raised and lowered in sections, and the condenser inlet water temperature is controlled to achieve energy saving effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the block diagram of the MGM COTAI chiller system. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore they cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; of course, it can also be a mechanical connection or an electrical connection; in addition, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Example 1

[0024] like Figure 1 Shown

[0025] A chiller system includes an MGMCOTAI chiller, a heat pump system, a freezer, and a chiller control system, wherein the chiller system is configured with 3 4000RT chillers (2000RTX2 series countercurrent) and 2 7.5MW heat pumps.

[0026] Example 2

[0027] The heat pump system provides 60°C heat pump hot water supply to the use site and produces 5.6°C chilled water at the same time.

[0028] Example 3

[0029] The refrigeration unit consists of a 2000RT×2 unit countercurrent structure in series. The refrigeration unit produces chilled water and hot water while recovering heat energy, and the highest cooling efficiency is achieved by using VSDS on the two chillers. The optimal control system simulates the performance characteristics of the chiller and determines the load settings of the two chillers to achieve the minimum energy consumption.

[0030] Example 4

[0031] The chiller control system consists of two parts: hardware design and software design. The PLC control system of the hardware design is designed for signal I / O and independent operation. The PLC control system is connected to the MGM company network, and all data in the PLC control system can be monitored in the network through a PC. The software design is a special control software developed for MGM to achieve full automatic control and optimal control. The MGM control system has 2 control software: monitoring software and optimal control software. The functions of the monitoring software include: PLC mode, PC mode, and monitoring; the functions of the optimal control software include: chiller system simulation, chiller optimal control settings, chillers, water pumps, cooling towers, and chiller performance.

[0032] Example 5

[0033] The control system of the data flow unit in the control system sends the shared memory to any PC in the MGM company network through Modbus communication. Every PC in the MGM company network can access the shared memory data of the control PC and display the operating data in real time. The shared memory saves all the operating data of the chiller system, the optimization control calculation results and the chiller performance evaluation results.

[0034] Example 6

[0035] The performance monitoring unit includes chiller performance monitoring and heat pump performance monitoring, wherein the chiller performance monitoring is used to evaluate the performance of the chiller and the heat pump in real time, and the heat pump performance monitoring can display the heat pump performance in real time.

[0036] Example 7

[0037] The common main system unit is equipped with a flow control valve and a flow meter, and performs control when the chiller is started: the control system checks whether the differential pressure and water pump speed of all chillers increase. If the differential pressure of the chiller is close to the tripping state, the following control is performed every 2 seconds until the chiller is started; control when the pump is started: the control system checks the header pressure every 2 seconds, controls the pump speed to keep the header pressure constant, and controls the pump to stop: the control system checks the header pressure every 2 seconds, and controls the pump speed to keep the header pressure unchanged.

[0038] Example 8

[0039] The energy management system records the loads of chilled water and hot water for operation effect analysis, wherein the energy management system has the function of providing power consumption breakdown.

[0040] Example 9

[0041] When the PC of the operating unit in the PLC fails, the chiller control system causes the chiller system to operate in the PLC mode.

[0042] Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention to illustrate the technical solutions of the present invention, rather than limiting them, and certainly not limiting the patent scope of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. In other words, any changes or modifications made to the main design concept and spirit of the present invention that have no substantive significance, and the technical problems they solve are still consistent with the present invention, should be included in the protection scope of the present invention. In addition, the direct or indirect application of the technical solutions of the present invention in other related technical fields is also included in the patent protection scope of the present invention.

Claims

1. A chiller system, comprising an MGM COTAI chiller, a heat pump system, a refrigerator, and a chiller control system.

2. A chiller system according to claim 1, characterized in that: The MGM COTAI chiller consists of three 4000RT chillers and two 7.5MW heat pump units.

3. A chiller system according to claim 1, characterized in that: The heat pump system provides 60°C heat pump hot water supply to the use site and produces 5.6°C chilled water at the same time.

4. A chiller system according to claim 1, characterized in that: The refrigerator is composed of 2000RT×2 units in series countercurrent structure.

5. A chiller system according to claim 1, characterized in that: The chiller control system consists of two parts: hardware design and software design. The PLC control system of the hardware design is designed for signal I / O and independent operation. The PLC control system is connected to the MGM company network, and all data in the PLC control system can be monitored in the network through a PC; the software design is a special control software developed for MGM. The MGM control system has 2 control software: monitoring software and optimal control software.

6. A chiller system according to claim 5, characterized in that: The software design includes a data flow unit in the control system. The control system sends the shared memory to any PC in the MGM company network through Modbus communication. Each PC in the MGM company network can access the shared memory data of the control PC and display the operating data in real time. The shared memory stores all the operating data of the chiller system, the optimization control calculation results and the chiller performance evaluation results.

7. A chiller system according to claim 5, characterized in that: The performance monitoring unit in the software design monitors the performance of the chiller and the heat pump.

8. A chiller system according to claim 5, characterized in that: The common main system unit in the software design is equipped with a flow control valve and a flow meter. The control system determines whether the differential pressure of the chiller and the speed of the water pump are abnormal and controls them when the chiller is started. The control system checks the header pressure and controls the pump speed to keep the header pressure constant to achieve the control effect when the pump is started. The control system checks the header pressure and controls the pump speed to keep the header pressure constant to achieve the effect of controlling the pump to stop.

9. A chiller system according to claim 5, characterized in that: The energy management system unit in the software design records the loads of chilled water and hot water for the functions of operating effect analysis and power consumption breakdown.

10. A chiller system according to claim 5, characterized in that: Operation unit in PLC in software design When the PC fails, the chiller control system makes the chiller system run in PLC mode.

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