Air and water double-cold-source water chilling unit system control method

Abstract

The invention belongs to the technical field of water chilling unit systems and control methods thereof, and particularly relates to an air and water double-cold-source water chilling unit system control method which comprises the following specific steps: step 1, data acquisition and calculation: user side basic data, equipment parameters and operation parameters are acquired respectively, and data are acquired and calculated; according to the water chilling unit system, the water pipe bundle heat exchange unit is added on the basis of a traditional evaporative water chilling unit system, a natural cold source can be fully utilized according to the cold load requirement of a user, and the water chilling unit system is more environmentally friendly; on the basis of collecting user basic data and equipment parameters, calculation models of user load, equipment heat exchange characteristics, system energy efficiency and the like are constructed, and parameters such as equipment energy efficiency, system energy efficiency, real-time refrigerating capacity, accumulated refrigerating capacity, sensible heat exchange capacity, latent heat exchange capacity, total heat exchange capacity, operation time and the like are adopted to jointly formulate a control strategy. Precise control over the water chilling unit system is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of chiller systems and control methods thereof, and in particular to a control method for a chiller system with dual cooling sources of air and water. Background Art

[0002] With the rapid development of my country's economy, industries such as metallurgy, semiconductors, biopharmaceuticals, and data centers are developing rapidly, and their demand for chiller systems is also increasing. However, the electric-driven chiller systems currently used in the form of air cooling, water cooling, or evaporative cooling consume a lot of energy. Especially for industries with a large number of year-round cooling needs, the operating energy consumption of electric-driven chiller systems is a challenge faced by many industries. Therefore, on the basis of meeting the cooling needs of the industry, it is of great significance to reduce the operating energy consumption of electric-driven chiller systems as much as possible.

[0003] At present, there are many methods or technologies to reduce the operating energy consumption of electric-driven chiller systems: some reduce system energy consumption by improving the refrigeration efficiency of the compressor itself; some reduce system energy consumption by reducing the operating time of the electric refrigeration system by coordinating the use of natural cooling sources such as outdoor air and outdoor water; and some reduce the energy consumption of the electric refrigeration system by optimizing the system control strategy. These methods and technologies can reduce the operating energy consumption of the electric refrigeration system to a certain extent, but considering the initial investment and land occupation of the newly added equipment, there is still uncertainty as to whether they are economical or reliable. In addition, the methods or technologies currently proposed often need to be optimized in matching with the operating logic of the electric-driven chiller system, and even the operating control logic of the electric-driven chiller system itself needs to be optimized. The operating energy consumption of the electric-driven chiller system is also affected by the differences in the cooling load characteristics of different industries, the climate differences in the regions where the buildings are located, the differences in the air cooling / water cooling / evaporative cooling heat exchange equipment used, and the differences in the types and grades of natural cooling sources. The control strategy formulation of the electric-driven chiller system should also consider these factors.

[0004] Therefore, it is urgent to fully consider the differences in the industry's cooling load characteristics, the climate differences in the areas where the industry's buildings are located, the differences in the condenser and evaporator equipment used, the sources and grades of the supplementary cold sources, and on this basis, reasonably design efficient and reliable heat transfer or energy form conversion equipment, accurately design control systems and formulate control strategies to achieve precise control of the electric-driven chiller system and optimal operating energy efficiency.

[0005] Therefore, a control method for a chiller system with air and water dual cooling sources is proposed to solve the above-mentioned problems. Summary of the invention

[0006] The object of the present invention is to provide a control method for a chiller system with air and water dual cooling sources to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a control method for a chiller system with air and water dual cooling sources, wherein the specific steps of the control method for a chiller system with air and water dual cooling sources are as follows: Step 1: Data collection and calculation: Collect basic data, equipment parameters and operating parameters on the user side respectively, and calculate the collected data through the thermal calculation model of the heat exchange equipment, the user side cooling demand calculation model, the chiller system cooling capacity calculation model and the chiller system efficiency calculation model; Step 2: Operation mode selection and judgment: There are two judgment methods as follows; Judgment method 1: Select based on system energy efficiency: The control device obtains the real-time cooling capacity required by the user side throughout the year and the maximum cooling capacity within the mode switching cycle based on the user side basic data and the user side cooling demand calculation model. At the same time, based on the user side basic data, equipment parameters and operating parameters, the calculation model of the cooling capacity and efficiency calculation model of the chiller system are called to obtain the cooling capacity and system energy efficiency of the chiller system under different operating modes in the near future. On this basis, the selection criteria for the operating mode of the chiller system are formed as follows: (1) The chiller system stops running: If the real-time cooling capacity required by the user side and the maximum cooling capacity in the recent period during the mode switching cycle are both less than zero, it means that the user does not need cooling, and the chiller system stops running; (2) Chiller system startup: If the real-time cooling capacity required by the user side within the shortest period of mode switching is not less than zero, it means that the user has cooling demand, and the chiller system needs to be started; The specific operation mode selection method is: S1) comparing the real-time cooling capacity required by the user side during the mode switching cycle with the real-time cooling capacity that can be provided by different operation modes of the system, and comparing the maximum cooling capacity required by the user side during the shortest mode switching cycle with the maximum cooling capacity of different operation modes of the system; S2) based on the comparison result, selecting a system operation mode in which both the real-time cooling capacity and the maximum cooling capacity within the mode switching period meet the user's needs; S3) Based on the selected system operation mode and the real-time cooling capacity required by the user side within the shortest switching period, the operating condition parameters under the system operation mode are optimized and set with the help of the thermal calculation model of the heat exchange equipment, so that the system operation mode meets the real-time cooling capacity requirements of the user side. With the help of the system energy efficiency calculation model, the real-time energy efficiency and cumulative energy efficiency of the system operation mode under the optimized operation condition parameters are obtained. The selected system operation mode has the best real-time energy efficiency and cumulative energy efficiency. This operation mode is the operation mode within the shortest switching period. S4) During operation, the matching relationship between the cooling capacity under the system operation mode and the demand on the user side is compared in real time. If the maximum cooling load demand on the user side increases sharply, the Fengshui operation mode of the system is directly operated to make the chiller system operate at the maximum cooling capacity to meet the user's needs; if the cooling load demand on the user side decreases sharply or no cooling is required, the operation mode operating condition parameters can be adjusted in real time to meet the user's needs; Judgment method 2: Select according to the heat exchange characteristics of the system heat exchange equipment: The control device calls the thermal calculation model of the heat exchange equipment according to the basic data on the user side, calculates the heat exchange characteristics of the refrigerant tube bundle heat exchange unit, the water tube bundle heat exchange unit, and the filler heat exchange unit heat exchange equipment when the heat exchange medium is air, water, air and water, refrigerant, etc., obtains the real-time and accumulated sensible heat exchange, latent heat exchange, and total heat exchange of air, water, or air and water in the mode switching cycle during the heat and mass exchange process of the heat exchange equipment; the real-time and accumulated power consumption of the fan and water pump, calls the user-side refrigeration demand calculation model, obtains the real-time cooling capacity and maximum cooling capacity in the mode switching cycle on the user side, and on this basis, forms the following selection criteria for the operation mode of the chiller system: (1) During the mode switching cycle, compare the real-time cooling capacity required by the user side with the real-time cooling capacity that can be provided by the system in different operating modes, and compare the maximum cooling capacity required by the user side with the maximum cooling capacity of the system in different operating modes. If the real-time cooling capacity and the maximum cooling capacity required by the user side during the mode switching cycle are both less than zero, it means that the user does not need cooling, and the chiller system stops running; if the real-time cooling capacity required by the user side during the shortest mode switching cycle is not less than zero, it means that the user has cooling needs, and the chiller system needs to be started. The specific operating mode is determined according to the heat exchange characteristics; (2) The chiller system is started and in operation. During the mode switching cycle, if the real-time cooling capacity and maximum cooling capacity required by the user side are both less than the real-time and maximum cooling capacity in the water direct cooling mode, the water direct cooling mode is operated. If the real-time and maximum cooling capacity in the water direct cooling mode cannot meet the real-time cooling capacity and maximum cooling capacity required by the user side during the mode switching cycle, other modes are operated. (3) The chiller system is turned on and running. During the mode switching cycle, when the real-time latent heat exchange rate is positive, it means that the evaporation of water can take away part of the condensation heat, and the air and water cooling refrigeration mode is running; (4) The chiller system is started and running. During the mode switching cycle, when the real-time latent heat exchange is negative, it means that there is no water evaporation, but water condensation occurs. Further compare the sensible heat exchange between water and refrigerant and between air and refrigerant. If the sensible heat exchange between air and refrigerant is greater than that of water, the air cooling refrigeration mode is operated, otherwise the water cooling refrigeration mode is operated. (5) The chiller system is started and operated. During the mode switching cycle, when the real-time latent heat exchange rate is positive or negative, the accumulated latent heat exchange rate and the accumulated total heat exchange rate are examined. 1) When the accumulated latent heat exchange rate is negative, further compare the accumulated total heat exchange rates between water and refrigerant and between air and refrigerant. If the accumulated total heat exchange rate between air and refrigerant is greater than that between water, operate the air cooling refrigeration mode; otherwise, operate the water cooling refrigeration mode. 2) When the accumulated latent heat exchange rate is positive, further compare the accumulated total heat exchange rates between water and refrigerant, between air and refrigerant, and between air, water and refrigeration. When the accumulated total heat exchange rate between water and refrigerant is the largest, operate the water cooling refrigeration mode. When the accumulated total heat exchange rate between air and refrigerant is the largest, operate the air cooling refrigeration mode. When the accumulated total heat exchange rate between air, water and refrigeration is the largest, operate the air and water cooling refrigeration mode.

[0008] Preferably, the thermal calculation model of the heat exchange equipment includes evaporator equipment parameters; thermal calculation models of heat exchange equipment such as refrigerant tube bundle heat exchange unit, water tube bundle heat exchange unit, and filler heat exchange unit, to realize heat exchange calculation of heat exchange equipment or determination of equipment structure parameters, by inputting parameters such as pipe material, inner and outer diameters / spacing / number of rows / arrangement parameters of pipe, filler material / spacing / specific surface area / height / width / thickness, physical properties of fluid (water, air, refrigerant) and flow mode, collecting flow, temperature and humidity parameters of fluid side (water, air and refrigerant), and then compiling a thermal calculation program of heat exchange equipment in MATLAB or other languages ​​based on the existing high-precision calculation model of heat exchange equipment, and calculating and obtaining the heat exchange amount under different fluid parameters under a certain structure of heat exchange equipment, including sensible heat exchange amount, latent heat exchange amount and total heat exchange amount; or according to the total heat exchange amount and heat exchange fluid parameters that need to be realized by the known heat exchange equipment, the structural parameters of the heat exchange equipment are calculated and determined.

[0009] Preferably, the user-side cooling demand calculation model monitors the basic data on the user side, uses load calculation software or MATLAB or other languages ​​to compile a calculation program for real-time and cumulative calculations to obtain the real-time cooling demand or cooling load on the user side.

[0010] Preferably, the cooling capacity calculation model of the chiller system is to collect the inlet and outlet temperatures, outlet flow rate and system operation time of the water entering the user side through real-time monitoring, and use MATLAB or other languages ​​to compile a calculation program for real-time and cumulative calculations to obtain the real-time cooling capacity or cooling power of the chiller system when the chiller system is running or when the natural cold source is cooling.

[0011] Preferably, the chiller system efficiency calculation model is a cooling capacity calculated based on the calculation model of the user-side cooling demand and the cooling capacity of the chiller system, combined with the energy consumption of fans, water pumps, compressors and other transportation equipment consumed by the chiller system during operation obtained by monitoring, and a calculation program is compiled using MATLAB or other languages ​​to perform real-time and cumulative calculations to obtain the system energy efficiency of the chiller system under various operating modes.

[0012] Preferably, in the operation mode selection and judgment step, the basic data on the user side includes meteorological data of the user's location, user indoor air calculation parameters, outdoor air calculation parameters, and user's cooling load data; and the chiller system sets the shortest period for switching the operation mode. Different shortest switching periods need to be set according to system characteristics, user load data, and indoor and outdoor air parameters to obtain the best system cumulative energy efficiency, generally 2-3 days is appropriate.

[0013] Preferably, in step one, the user-side basic data includes meteorological data of the user's location, user indoor air calculation parameters, outdoor air calculation parameters, and user's cooling load data; the equipment parameters include evaporator equipment parameters, refrigerant tube bundle heat exchange unit equipment parameters, water tube bundle heat exchange unit equipment parameters, packing heat exchange unit equipment parameters, compressor and expansion valve equipment parameters; the operating parameters include air, water, refrigerant temperature, humidity, flow, wind speed, water speed, power consumption, and operating time parameters collected by the control equipment.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1) The chiller system proposed in the present invention adds a water tube bundle heat exchange unit on the basis of the traditional evaporative chiller system, which can make full use of the natural cold source according to the user's cooling load demand, and the chiller system is more environmentally friendly; 2) The chiller system control method proposed in the present invention does not simply use temperature, temperature difference or operating time for control, but builds calculation models such as user load, equipment heat exchange characteristics and system energy efficiency based on the collection of user basic data (including external meteorological parameters, system operation data and user load data, etc.) and equipment parameters. The control strategy is jointly formulated using parameters such as equipment energy efficiency, system energy efficiency, real-time cooling capacity, cumulative cooling capacity, sensible heat exchange, latent heat exchange, total heat exchange and operating time, thereby achieving precise control of the chiller system and optimal operating energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of an air-water dual-cooling source chiller system; Figure 2 This is a schematic diagram of a single air-cooling cooling mode; Figure 3 It is a schematic diagram of a single water-cooling refrigeration mode; Figure 4 It is a schematic diagram of the refrigeration mode of air and water cooling; Figure 5 It is a schematic diagram of the open water direct cooling mode; Figure 6 It is a schematic diagram of closed water direct cooling mode; Figure 7 is the operation control logic diagram of the air-water dual-cooling source chiller system ( Figure 7a It is controlled according to the system energy consumption; Figure 7b is controlled according to the heat transfer characteristics of the system).

[0016] In the figure: 1-first variable frequency circulating water pump, 2-evaporator, 3-compressor, 4-oil separator, 5-fan, 6-water baffle, 7-spraying device, 8-refrigerant coil heat exchange unit, 9-filler heat exchange unit, 10-water coil bundle heat exchange unit, 11-water receiving tray, 12-second variable frequency circulating water pump, 13-control equipment. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0019] Embodiment 1: See also Figure 1 -7. The present invention provides a technical solution: A control method for a chiller system with dual cooling sources of air and water, the specific steps of the control method for a chiller system with dual cooling sources of air and water are as follows: Step 1: Data collection and calculation: Collect basic data, equipment parameters and operating parameters on the user side respectively, and calculate the collected data through the thermal calculation model of the heat exchange equipment, the user side cooling demand calculation model, the chiller system cooling capacity calculation model and the chiller system efficiency calculation model; Step 2: Operation mode selection and judgment: There are two judgment methods as follows; Judgment method 1: Select based on system energy efficiency: The control device obtains the real-time cooling capacity required by the user side throughout the year and the maximum cooling capacity within the mode switching cycle based on the user side basic data and the user side cooling demand calculation model. At the same time, based on the user side basic data, equipment parameters and operating parameters, the calculation model of the cooling capacity and efficiency calculation model of the chiller system are called to obtain the cooling capacity and system energy efficiency of the chiller system under different operating modes in the near future. On this basis, the selection criteria for the operating mode of the chiller system are formed as follows: (1) The chiller system stops running: If the real-time cooling capacity required by the user side and the maximum cooling capacity in the recent period during the mode switching cycle are both less than zero, it means that the user does not need cooling, and the chiller system stops running; (2) Chiller system startup: If the real-time cooling capacity required by the user side within the shortest period of mode switching is not less than zero, it means that the user has cooling demand, and the chiller system needs to be started; The specific operation mode selection method is: S1) comparing the real-time cooling capacity required by the user side during the mode switching cycle with the real-time cooling capacity that can be provided by different operation modes of the system, and comparing the maximum cooling capacity required by the user side during the shortest mode switching cycle with the maximum cooling capacity of different operation modes of the system; S2) based on the comparison result, selecting a system operation mode in which both the real-time cooling capacity and the maximum cooling capacity within the mode switching period meet the user's needs; S3) Based on the selected system operation mode and the real-time cooling capacity required by the user side within the shortest switching period, the operating condition parameters under the system operation mode are optimized and set with the help of the thermal calculation model of the heat exchange equipment, so that the system operation mode meets the real-time cooling capacity requirements of the user side. With the help of the system energy efficiency calculation model, the real-time energy efficiency and cumulative energy efficiency of the system operation mode under the optimized operation condition parameters are obtained. The selected system operation mode has the best real-time energy efficiency and cumulative energy efficiency. This operation mode is the operation mode within the shortest switching period. S4) During operation, the matching relationship between the cooling capacity under the system operation mode and the demand on the user side is compared in real time. If the maximum cooling load demand on the user side increases sharply, the Fengshui operation mode of the system is directly operated to make the chiller system operate at the maximum cooling capacity to meet the user's needs; if the cooling load demand on the user side decreases sharply or no cooling is required, the operation mode operating condition parameters can be adjusted in real time to meet the user's needs; Judgment method 2: Select according to the heat exchange characteristics of the system heat exchange equipment: The control device calls the thermal calculation model of the heat exchange equipment according to the basic data on the user side, calculates the heat exchange characteristics of the refrigerant tube bundle heat exchange unit, the water tube bundle heat exchange unit, and the filler heat exchange unit heat exchange equipment when the heat exchange medium is air, water, air and water, refrigerant, etc., obtains the real-time and accumulated sensible heat exchange, latent heat exchange, and total heat exchange of air, water, or air and water in the mode switching cycle during the heat and mass exchange process of the heat exchange equipment; the real-time and accumulated power consumption of the fan and water pump, calls the user-side refrigeration demand calculation model, obtains the real-time cooling capacity and maximum cooling capacity in the mode switching cycle on the user side, and on this basis, forms the following selection criteria for the operation mode of the chiller system: (1) During the mode switching cycle, compare the real-time cooling capacity required by the user side with the real-time cooling capacity that can be provided by the system in different operating modes, and compare the maximum cooling capacity required by the user side with the maximum cooling capacity of the system in different operating modes. If the real-time cooling capacity and the maximum cooling capacity required by the user side during the mode switching cycle are both less than zero, it means that the user does not need cooling, and the chiller system stops running; if the real-time cooling capacity required by the user side during the shortest mode switching cycle is not less than zero, it means that the user has cooling needs, and the chiller system needs to be started. The specific operating mode is determined according to the heat exchange characteristics; (2) The chiller system is started and in operation. During the mode switching cycle, if the real-time cooling capacity and maximum cooling capacity required by the user side are both less than the real-time and maximum cooling capacity in the water direct cooling mode, the water direct cooling mode is operated. If the real-time and maximum cooling capacity in the water direct cooling mode cannot meet the real-time cooling capacity and maximum cooling capacity required by the user side during the mode switching cycle, other modes are operated. (3) The chiller system is turned on and running. During the mode switching cycle, when the real-time latent heat exchange rate is positive, it means that the evaporation of water can take away part of the condensation heat, and the air and water cooling refrigeration mode is running; (4) The chiller system is started and running. During the mode switching cycle, when the real-time latent heat exchange is negative, it means that there is no water evaporation, but water condensation occurs. Further compare the sensible heat exchange between water and refrigerant and between air and refrigerant. If the sensible heat exchange between air and refrigerant is greater than that of water, the air cooling refrigeration mode is operated, otherwise the water cooling refrigeration mode is operated. (5) The chiller system is started and operated. During the mode switching cycle, when the real-time latent heat exchange rate is positive or negative, the accumulated latent heat exchange rate and the accumulated total heat exchange rate are examined. 1) When the accumulated latent heat exchange rate is negative, further compare the accumulated total heat exchange rates between water and refrigerant and between air and refrigerant. If the accumulated total heat exchange rate between air and refrigerant is greater than that between water, operate the air cooling refrigeration mode; otherwise, operate the water cooling refrigeration mode. 2) When the accumulated latent heat exchange rate is positive, further compare the accumulated total heat exchange rates between water and refrigerant, between air and refrigerant, and between air, water and refrigeration. When the accumulated total heat exchange rate between water and refrigerant is the largest, operate the water cooling refrigeration mode. When the accumulated total heat exchange rate between air and refrigerant is the largest, operate the air cooling refrigeration mode. When the accumulated total heat exchange rate between air, water and refrigeration is the largest, operate the air and water cooling refrigeration mode.

[0020] The thermal calculation model of the heat exchange equipment includes evaporator equipment parameters; thermal calculation models of heat exchange equipment such as refrigerant tube bundle heat exchange unit, water tube bundle heat exchange unit, and filler heat exchange unit, so as to realize heat exchange calculation of the heat exchange equipment or determine the equipment structure parameters. By inputting parameters such as pipe material, inner and outer diameters / spacing / number of rows / arrangement parameters of the pipe, filler material / spacing / specific surface area / height / width / thickness, physical properties of fluid (water, air, refrigerant) and flow mode, the flow rate, temperature and humidity parameters of the fluid side (water, air and refrigerant) are collected, and then according to the existing high-precision heat exchange equipment calculation model, the heat exchange equipment thermal calculation program is compiled using MATLAB or other languages ​​to calculate and obtain the heat exchange under different fluid parameters under a certain heat exchange equipment structure, including sensible heat exchange, latent heat exchange and total heat exchange; or according to the total heat exchange required to be realized by the known heat exchange equipment and the heat exchange fluid parameters, the structural parameters of the heat exchange equipment are calculated and determined.

[0021] The user side cooling demand calculation model monitors the basic data of the above user side, uses load calculation software or MATLAB or other languages ​​to compile calculation programs for real-time and cumulative calculations to obtain the real-time cooling demand or cooling load of the user side.

[0022] The cooling capacity calculation model of the chiller system is to obtain the real-time cooling capacity or cooling power of the chiller system when the chiller system is running or when the natural cold source is cooling by real-time monitoring and collecting the inlet and outlet temperatures, outlet flow rate and system operation time of the water entering the user side, and using MATLAB or other languages ​​to compile a calculation program for real-time and cumulative calculation.

[0023] The chiller system efficiency calculation model is a cooling capacity calculated based on the calculation model of the user-side cooling demand and the cooling capacity of the chiller system, combined with the energy consumption of fans, water pumps, compressors and other transportation equipment consumed by the chiller system during operation obtained by monitoring, and a calculation program compiled using MATLAB or other languages ​​for real-time and cumulative calculations to calculate the system energy efficiency of the chiller system under various operating modes.

[0024] In the operation mode selection and judgment step, the basic data on the user side includes the meteorological data of the user's location, the user's indoor air calculation parameters, the outdoor air calculation parameters, and the user's cooling load data; and the chiller system sets the shortest period for switching the operation mode. Different shortest switching periods need to be set according to system characteristics, user load data, and indoor and outdoor air parameters to obtain the best system cumulative energy efficiency, generally 2-3 days is appropriate.

[0025] In the step one, the user-side basic data includes meteorological data of the user's location, user indoor air calculation parameters, outdoor air calculation parameters, and user's cooling load data; the equipment parameters include evaporator equipment parameters, refrigerant tube bundle heat exchange unit equipment parameters, water tube bundle heat exchange unit equipment parameters, packing heat exchange unit equipment parameters, compressor and expansion valve equipment parameters; the operating parameters include air, water, refrigerant temperature, humidity, flow, wind speed, water speed, power consumption, and operating time parameters collected by the control equipment.

[0026] Embodiment 2: The air-water dual-cooling source chiller system includes a compressor, an evaporator, a packing-coil evaporative condenser, a throttle valve and control equipment, as well as auxiliary equipment such as a water supply constant pressure device and an oil separator. In addition to the control equipment, the equipment is connected through pipelines, and various valves, filters, flexible connections, measuring equipment and other accessories are installed on the pipelines (see Figure 1 The signal lines and control lines of the equipment and accessories (partial valve accessories containing control signals, measuring equipment, etc.) are connected to the control equipment; The evaporator, compressor, throttle valve, oil separator, fan, water baffle, water supply constant pressure device, spray device, water tray, various types of valves, filters, flexible connections and other equipment are no different from the equipment in the traditional chiller system and will not be elaborated. The first variable frequency circulating water pump is the user-side circulating water pump, which delivers the chilled water in the water tray, water coil bundle heat exchange unit or evaporator to the user end; the second variable frequency circulating water pump is a spray water pump (cooling water pump), which sucks the cooling water from the water tray and sprays it evenly onto the outer surface of the coil and filler through the nozzle of the spray device; The structure of the packing-coil evaporative condenser is basically similar to that of the traditional packing-coil evaporative condenser, except that the packing-coil evaporative condenser in the present invention has a water coil tube bundle heat exchange unit in addition to the refrigerant coil heat exchange unit and the packing heat exchange unit. When the packing-coil evaporative condenser is working, the refrigerant flows in the refrigerant coil heat exchange unit, and the air or water flows outside the tube bundle; the water flows in the water coil tube bundle heat exchange unit, and the air or water flows outside the tube bundle; the air and water flow in the packing heat exchange unit; the air and water can pass through the outside of the coil and the packing alone or simultaneously, and the medium in the tube bundle and the medium outside the tube bundle exchange sensible heat, and the direction of heat transfer depends on the dry bulb temperature difference between the air and the water, and the air after the heat exchange is discharged into the atmosphere. For the packed heat exchange unit, water and air are in direct contact to carry out heat and mass transfer process, and water and air exchange sensible heat and latent heat. The direction of sensible heat transfer depends on the dry bulb temperature of air and water, and the latent heat transfer depends on the moisture content of air and the moisture content of air near the water film surface. The total heat transfer direction depends on the algebraic sum of sensible heat and latent heat.

[0027] The measuring equipment includes temperature and pressure probes installed at the inlet and outlet of the compressor; temperature and pressure probes installed at the inlet and outlet of the refrigerant side and the chilled water side of the shell and tube evaporator, and a flow probe installed at the water side; temperature and pressure probes installed at the inlet and outlet of the refrigerant coil of the packing-coil evaporative condenser, temperature and flow probes installed at the inlet and outlet of the water coil, temperature probes installed at the air outlet outside the coil and packing, wind speed probes, temperature probes and humidity probes installed at the air inlet; temperature and pressure probes installed at the inlet and outlet of the throttle valve; electric energy meters installed at the compressor, fan, water pump and other conveying equipment. The temperature probe, humidity probe, flow probe, wind speed probe and electric energy meter are all connected to the control equipment.

[0028] The control device includes a calculation model module, a data acquisition and storage module, a data processing module, a judgment forming module, an execution module, etc.

[0029] (1) Calculation model module: including the thermal calculation model of the heat exchange equipment in the chiller system, the energy efficiency calculation model of the chiller system, and the cooling load calculation model on the user side; (2) Data acquisition and storage module: collects and stores data such as the start and stop status of the equipment, the test data of the aforementioned probes, the structural parameters of the heat exchange equipment, the start and shutdown conditions of the chiller, etc.; (3) Data processing module: Based on the collected and stored data, the calculation model of the calculation model module is called to calculate the real-time and cumulative sensible heat transfer, latent heat transfer, and total heat transfer in the heat and mass exchange process of the heat exchange equipment; the real-time and cumulative power consumption of the compressor, fan, and water pump; the real-time and cumulative cooling capacity on the cooling side or user side; the real-time and cumulative equipment energy efficiency value and system energy efficiency value under various operating modes; (4) Criteria formation module: The data obtained by the calculation model module, the data acquisition and storage module, and the data processing module are compared with the pre-set values ​​to form the criteria for the system execution operation mode; (5) Execution module: Completes the operation control and switching of the system's operation mode according to the criteria formed by the criteria forming module.

[0030] The air-water dual-cooling source chiller system can realize the following operating modes and operating characteristics through control: (1) Air-cooled cooling mode: In this operation mode, the compressor and the refrigerant coil heat exchange unit operate jointly, the water coil tube bundle heat exchange unit and the packing heat exchange unit do not operate, and the outside of the tube bundle of the refrigerant coil heat exchange unit exchanges heat with the air. At this time, the refrigerant on the refrigerant circulation side flows through the compressor, oil separator, refrigerant coil heat exchange unit, expansion valve, evaporator and returns to the compressor to complete the refrigeration cycle. The cold water produced by the evaporator is used for cooling users, and the condensation heat of the refrigerant coil heat exchange unit is taken away by the air outside the tube. The chiller system is equivalent to a traditional air-cooled chiller that operates to cool users; (2) Single water cooling refrigeration mode: In this operation mode, the compressor and the refrigerant coil heat exchange unit operate jointly, the water coil tube bundle heat exchange unit and the packing heat exchange unit do not operate, and the outer side of the tube bundle of the refrigerant coil heat exchange unit exchanges heat with the spray water. At this time, the refrigerant on the refrigerant circulation side flows through the compressor, oil separator, refrigerant coil heat exchange unit, expansion valve, evaporator and returns to the compressor to complete the refrigeration cycle. The cold water produced by the evaporator is used for cooling the user, and the condensation heat of the refrigerant coil heat exchange unit is taken away by the water outside the tube. The chiller system is equivalent to a traditional water-cooled chiller that operates to cool the user; (3) Air and water cooling refrigeration mode: In this operation mode, the compressor operates in conjunction with the refrigerant coil heat exchange unit and the packing heat exchange unit, while the water coil bundle heat exchange unit does not operate. The outside of the bundle of the refrigerant coil heat exchange unit exchanges heat with the spray water, and the spray water after heat exchange exchanges heat with the air in the packing heat exchange unit, and then is pumped to the outside of the bundle of the refrigerant coil heat exchange unit for heat exchange through a water pump. At this time, the refrigerant on the refrigerant circulation side flows through the compressor, oil separator, refrigerant coil heat exchange unit, expansion valve, evaporator and returns to the compressor, completing the refrigeration cycle. The cold water produced by the evaporator is used for user cooling, and the condensation heat of the refrigerant coil heat exchange unit is taken away by the water outside the tube, while the heat of the water is taken away by the air and water evaporation. The chiller system is equivalent to a traditional evaporative chiller that operates to provide cooling to users. (4) Water direct cooling mode: The water direct cooling mode is divided into open water direct cooling mode and closed water direct cooling mode. When the user side does not have high requirements on water quality, the open water direct cooling mode is operated. In this mode, the compressor does not run, and the return water on the user side is directly sprayed to the packing heat exchange unit, and is cooled by heat exchange with the outdoor air. The cooled water is directly sent to the user for cooling; when the user side has high requirements on water quality, the closed water direct cooling mode is operated. In this mode, the return water on the user side is sent to the water coil bundle heat exchange unit, and the outside of the water coil bundle heat exchange unit exchanges heat with the outdoor air, and the cooled water is directly sent to the user for cooling. The chiller system is equivalent to directly using ambient air to produce cold water or using natural cold water to cool the user.

[0031] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A control method for a chiller system with dual cooling sources of air and water, characterized in that: The specific steps of the air and water dual-cooling source chiller system control method are as follows: Step 1: Data collection and calculation: Collect basic data, equipment parameters and operating parameters on the user side respectively, and calculate the collected data through the thermal calculation model of the heat exchange equipment, the user side cooling demand calculation model, the chiller system cooling capacity calculation model and the chiller system efficiency calculation model; Step 2: Operation mode selection and judgment: There are two judgment methods as follows; Judgment method 1: Select based on system energy efficiency: The control device obtains the real-time cooling capacity required by the user side throughout the year and the maximum cooling capacity within the mode switching cycle based on the user side basic data and the user side cooling demand calculation model. At the same time, based on the user side basic data, equipment parameters and operating parameters, the calculation model of the cooling capacity and efficiency calculation model of the chiller system are called to obtain the cooling capacity and system energy efficiency of the chiller system under different operating modes in the near future. On this basis, the selection criteria for the operating mode of the chiller system are formed as follows: (1) The chiller system stops running: If the real-time cooling capacity required by the user side and the maximum cooling capacity in the recent period during the mode switching cycle are both less than zero, it means that the user does not need cooling, and the chiller system stops running; (2) Chiller system startup: If the real-time cooling capacity required by the user side within the shortest period of mode switching is not less than zero, it means that the user has cooling demand, and the chiller system needs to be started; The specific operation mode selection method is: S1) comparing the real-time cooling capacity required by the user side during the mode switching cycle with the real-time cooling capacity that can be provided by different operation modes of the system, and comparing the maximum cooling capacity required by the user side during the shortest mode switching cycle with the maximum cooling capacity of different operation modes of the system; S2) based on the comparison result, selecting a system operation mode in which both the real-time cooling capacity and the maximum cooling capacity within the mode switching period meet the user's needs; S3) Based on the selected system operation mode and the real-time cooling capacity required by the user side within the shortest switching period, the operating condition parameters under the system operation mode are optimized and set with the help of the thermal calculation model of the heat exchange equipment, so that the system operation mode meets the real-time cooling capacity requirements of the user side. With the help of the system energy efficiency calculation model, the real-time energy efficiency and cumulative energy efficiency of the system operation mode under the optimized operation condition parameters are obtained. The selected system operation mode has the best real-time energy efficiency and cumulative energy efficiency. This operation mode is the operation mode within the shortest switching period. S4) During operation, the matching relationship between the cooling capacity under the system operation mode and the demand on the user side is compared in real time. If the maximum cooling load demand on the user side increases sharply, the Fengshui operation mode of the system is directly operated to make the chiller system operate at the maximum cooling capacity to meet the user's needs; if the cooling load demand on the user side decreases sharply or no cooling is required, the operation mode operating condition parameters can be adjusted in real time to meet the user's needs; Judgment method 2: Select according to the heat exchange characteristics of the system heat exchange equipment: The control device calls the thermal calculation model of the heat exchange equipment according to the basic data on the user side, calculates the heat exchange characteristics of the refrigerant tube bundle heat exchange unit, the water tube bundle heat exchange unit, and the filler heat exchange unit heat exchange equipment when the heat exchange medium is air, water, air and water, refrigerant, etc., obtains the real-time and accumulated sensible heat exchange, latent heat exchange, and total heat exchange of air, water, or air and water in the mode switching cycle during the heat and mass exchange process of the heat exchange equipment; the real-time and accumulated power consumption of the fan and water pump, calls the user-side refrigeration demand calculation model, obtains the real-time cooling capacity and maximum cooling capacity in the mode switching cycle on the user side, and on this basis, forms the following selection criteria for the operation mode of the chiller system: (1) During the mode switching cycle, compare the real-time cooling capacity required by the user side with the real-time cooling capacity that can be provided by the system in different operating modes, and compare the maximum cooling capacity required by the user side with the maximum cooling capacity of the system in different operating modes. If the real-time cooling capacity and the maximum cooling capacity required by the user side during the mode switching cycle are both less than zero, it means that the user does not need cooling, and the chiller system stops running; if the real-time cooling capacity required by the user side during the shortest mode switching cycle is not less than zero, it means that the user has cooling needs, and the chiller system needs to be started. The specific operating mode is determined according to the heat exchange characteristics; (2) The chiller system is started and in operation. During the mode switching cycle, if the real-time cooling capacity and maximum cooling capacity required by the user side are both less than the real-time and maximum cooling capacity in the water direct cooling mode, the water direct cooling mode is operated. If the real-time and maximum cooling capacity in the water direct cooling mode cannot meet the real-time cooling capacity and maximum cooling capacity required by the user side during the mode switching cycle, other modes are operated. (3) The chiller system is turned on and running. During the mode switching cycle, when the real-time latent heat exchange rate is positive, it means that the evaporation of water can take away part of the condensation heat, and the air and water cooling refrigeration mode is running; (4) The chiller system is started and running. During the mode switching cycle, when the real-time latent heat exchange is negative, it means that there is no water evaporation, but water condensation occurs. Further compare the sensible heat exchange between water and refrigerant and between air and refrigerant. If the sensible heat exchange between air and refrigerant is greater than that of water, the air cooling refrigeration mode is operated, otherwise the water cooling refrigeration mode is operated. (5) The chiller system is started and operated. During the mode switching cycle, when the real-time latent heat exchange rate is positive or negative, the accumulated latent heat exchange rate and the accumulated total heat exchange rate are examined. 1) When the accumulated latent heat exchange rate is negative, further compare the accumulated total heat exchange rates between water and refrigerant and between air and refrigerant. If the accumulated total heat exchange rate between air and refrigerant is greater than that between water, operate the air cooling refrigeration mode; otherwise, operate the water cooling refrigeration mode. 2) When the accumulated latent heat exchange rate is positive, further compare the accumulated total heat exchange rates between water and refrigerant, between air and refrigerant, and between air, water and refrigeration. When the accumulated total heat exchange rate between water and refrigerant is the largest, operate the water cooling refrigeration mode. When the accumulated total heat exchange rate between air and refrigerant is the largest, operate the air cooling refrigeration mode. When the accumulated total heat exchange rate between air, water and refrigeration is the largest, operate the air and water cooling refrigeration mode.

2. The air and water dual-cooling source chiller system control method according to claim 1, characterized in that: The thermal calculation model of the heat exchange equipment includes evaporator equipment parameters; thermal calculation models of heat exchange equipment such as refrigerant tube bundle heat exchange unit, water tube bundle heat exchange unit, and filler heat exchange unit, so as to realize heat exchange calculation of the heat exchange equipment or determine the equipment structure parameters. By inputting parameters such as pipe material, inner and outer diameters / spacing / number of rows / arrangement parameters of the pipe, filler material / spacing / specific surface area / height / width / thickness, physical properties of fluid (water, air, refrigerant) and flow mode, the flow rate, temperature and humidity parameters of the fluid side (water, air and refrigerant) are collected, and then according to the existing high-precision heat exchange equipment calculation model, the heat exchange equipment thermal calculation program is compiled using MATLAB or other languages ​​to calculate and obtain the heat exchange under different fluid parameters under a certain heat exchange equipment structure, including sensible heat exchange, latent heat exchange and total heat exchange; or according to the total heat exchange required to be realized by the known heat exchange equipment and the heat exchange fluid parameters, the structural parameters of the heat exchange equipment are calculated and determined.

3. The air and water dual-cooling source chiller system control method according to claim 1, characterized in that: The user side cooling demand calculation model monitors the basic data of the above user side, uses load calculation software or MATLAB or other languages ​​to compile calculation programs for real-time and cumulative calculations to obtain the real-time cooling demand or cooling load of the user side.

4. The air and water dual-cooling source chiller system control method according to claim 1, characterized in that: The cooling capacity calculation model of the chiller system is to obtain the real-time cooling capacity or cooling power of the chiller system when the chiller system is running or when the natural cold source is cooling by real-time monitoring and collecting the inlet and outlet temperatures, outlet flow rate and system operation time of the water entering the user side, and using MATLAB or other languages ​​to compile a calculation program for real-time and cumulative calculation.

5. The air and water dual-cooling source chiller system control method according to claim 1, characterized in that: The chiller system efficiency calculation model is a cooling capacity calculated based on the calculation model of the user-side cooling demand and the cooling capacity of the chiller system, combined with the energy consumption of fans, water pumps, compressors and other transportation equipment consumed by the chiller system during operation obtained by monitoring, and a calculation program compiled using MATLAB or other languages ​​for real-time and cumulative calculations to calculate the system energy efficiency of the chiller system under various operating modes.

6. The air and water dual-cooling source chiller system control method according to claim 1, characterized in that: In the operation mode selection and judgment step, the basic data on the user side includes the meteorological data of the user's location, the user's indoor air calculation parameters, the outdoor air calculation parameters, and the user's cooling load data; and the chiller system sets the shortest period for switching the operation mode. Different shortest switching periods need to be set according to system characteristics, user load data, and indoor and outdoor air parameters to obtain the best system cumulative energy efficiency, generally 2-3 days is appropriate.

7. The air and water dual-cooling source chiller system control method according to claim 1, characterized in that: In the step one, the user-side basic data includes meteorological data of the user's location, user indoor air calculation parameters, outdoor air calculation parameters, and user's cooling load data; the equipment parameters include evaporator equipment parameters, refrigerant tube bundle heat exchange unit equipment parameters, water tube bundle heat exchange unit equipment parameters, packing heat exchange unit equipment parameters, compressor and expansion valve equipment parameters; the operating parameters include air, water, refrigerant temperature, humidity, flow, wind speed, water speed, power consumption, and operating time parameters collected by the control equipment.

Images