Water-cooled air conditioning system and control method thereof

Abstract

The invention relates to a water-cooled air conditioning system and a control method thereof. The water-cooled air conditioning system comprises an air conditioning terminal device, a water chilling unit and a pipeline connected between the air conditioning terminal device and the water chilling unit. The pipeline comprises a water return pipeline and a water supply pipeline; one end of the water return pipeline is connected with the water outlet end of the air-conditioning terminal device, and the other end is connected with the input end of an evaporator of the water chilling unit; one end of the water supply pipeline is connected with the output end of the evaporator, and the other end is connected with the water inlet end of the air-conditioning terminal device; the water-cooled air conditioning system further comprises a heating assembly used for heating chilled water introduced into the evaporator, and the heating assembly is installed on the water return pipeline. According to the water-cooled air conditioning system, the cooling load of the water chilling unit is increased in a cooling water heating mode through the external heating assembly, so that the water chilling unit can get rid of the low-load operation condition, and the water chilling unit can be guaranteed to operate stably.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and in particular to a water-cooled air-conditioning system and a control method thereof. Background Art

[0002] Centrifugal chillers are the main refrigeration equipment for large-scale water-cooled central air-conditioning systems. Their core component, the centrifugal compressor, is a speed-type compressor. Due to its compression characteristics, surge may occur under low-load conditions (the low-load condition of a conventional single-stage compression chiller is generally less than 30% to 40% of the rated cooling capacity of the unit), causing serious damage to the compressor.

[0003] Although relevant technologies have been developed to cope with low-load conditions at the equipment level, such as variable frequency control, multi-stage compression, hot gas bypass and other technologies, for old central air conditioners that have been put on the market and have not adopted new technologies, the method of coping with low-load conditions is generally through multiple starts and stops of the chiller. However, the frequent start and stop of the chiller will lead to accelerated equipment life and increased energy consumption on the one hand, and on the other hand, it cannot guarantee the stability of the cooling supply of the air-conditioning terminal device, affecting the comfort of the air-conditioning. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a water-cooled air-conditioning system and a control method thereof.

[0005] The technical solution adopted by the present invention to solve the technical problem is: constructing a water-cooled air-conditioning system, including an air-conditioning terminal device, a chiller, and a pipeline connected between the air-conditioning terminal device and the chiller;

[0006] The pipeline includes a return pipe and a water supply pipe; one end of the return pipe is connected to the water outlet of the air conditioner terminal device, and the other end is connected to the input end of the evaporator of the chiller; one end of the water supply pipe is connected to the output end of the evaporator, and the other end is connected to the water inlet end of the air conditioner terminal device;

[0007] The water-cooled air conditioning system further comprises a heating component for heating the chilled water flowing into the evaporator, and the heating component is installed on the water return pipeline.

[0008] In some embodiments, the water-cooled air conditioning system further includes a monitoring component and a controller connected to the monitoring component; the controller is connected to the heating component to switch the working state of the heating component according to the data collected by the monitoring component;

[0009] The monitoring component includes a flow meter connected to the pipeline, a first temperature sensor connected to an upstream position of the heating component, and a third temperature sensor connected to a downstream position of the evaporator.

[0010] In some embodiments, the monitoring assembly further comprises a second temperature sensor connected at a downstream position of the heating assembly.

[0011] In some embodiments, the heating assembly includes an electric heating wire, and the electric heating wire is wound around the return pipe;

[0012] The water-cooled air conditioning system further includes at least one power supply component connected to the heating component.

[0013] In some embodiments, the single power supply component is one of a photovoltaic power supply component, an energy storage power supply component, and a grid power supply component;

[0014] The photovoltaic power supply assembly includes a photovoltaic panel and a photovoltaic power switch, the photovoltaic panel and the heating assembly are provided with a connecting circuit, and the photovoltaic power switch is arranged at the connecting circuit between the photovoltaic panel and the heating assembly;

[0015] The energy storage power supply assembly includes an energy storage battery pack and an energy storage power supply switch, the energy storage battery pack and the heating assembly are provided with a connection circuit, and the energy storage power supply switch is arranged at the connection circuit between the energy storage battery pack and the heating assembly;

[0016] The grid power supply component includes a power access terminal for accessing the mains, a rectifier connected to the power access terminal, and a grid power supply switch; a connecting circuit is provided between the rectifier and the heating component, and the grid power supply switch is arranged at the connecting circuit between the rectifier and the heating component.

[0017] In some embodiments, the water-cooled air conditioning system includes a photovoltaic power component, an energy storage power component, and a grid power component;

[0018] A connection circuit is provided between the photovoltaic panel and the energy storage battery pack, and the photovoltaic power supply assembly further includes a photovoltaic power storage switch, which is provided at the connection circuit between the photovoltaic panel and the energy storage battery pack;

[0019] A connection circuit is provided between the rectifier and the energy storage battery pack, and the grid power supply component further includes a grid power storage switch, which is provided between the rectifier and the energy storage battery pack.

[0020] The present application also constructs a control method applied to the above-mentioned water-cooled air-conditioning system, the control method comprising:

[0021] S1: After the chiller is started, the circulation flow data and temperature data of the chilled water are continuously obtained, wherein the temperature data includes the temperature data of the chilled water when it is output from the air-conditioning terminal device and the temperature data of the chilled water after being cooled by the evaporator;

[0022] S2: obtaining the cooling load of the air-conditioning terminal device according to the circulation flow data, the temperature data of the chilled water when it is output from the air-conditioning terminal device, and the temperature data of the chilled water after being cooled by the evaporator;

[0023] S3: Determine the difference between the cooling load of the air-conditioning terminal device and a preset low-load critical value, and when it is determined that the cooling load of the air-conditioning terminal device is less than the low-load critical value, control the heating component to operate.

[0024] In some embodiments, in step S1, the temperature data also includes temperature data of chilled water when it enters the chiller;

[0025] After step S1, the method further includes the following steps:

[0026] S25: obtaining a cooling load of the chiller according to the circulation flow data, the temperature data of the chilled water when entering the chiller, and the temperature data of the chilled water after being cooled by the evaporator;

[0027] The step S3 comprises the following sub-steps:

[0028] S31: Acquire the working state of the heating component, where the working state includes a running state and a shutdown state;

[0029] S32: when the heating component is in the shutdown state, determining the difference between the cooling load of the air-conditioning terminal device and the low load critical value, and when determining that the cooling load of the air-conditioning terminal device is less than the low load critical value, controlling the heating component to enter the operating state;

[0030] S33: When the heating component is in operation, determine the difference between the cooling load of the chiller and the low load critical value, and when it is determined that the cooling load of the chiller is at least not less than the low load critical value, control the heating component to enter a shutdown state.

[0031] In some embodiments, in step S3, the cooling load is calculated according to the following formula:

[0032] Q=3600·c·F·ΔT

[0033] Among them, Q is used to represent the cooling load; c is used to represent the specific heat capacity; △T is used to represent the change in cooling water temperature; 3600 is the conversion factor for converting hours to seconds.

[0034] In some embodiments, in step S33, the judgment condition for controlling the heating component to enter a shutdown state also includes: the cooling load of the chiller is greater than or equal to the value of the low load critical value multiplied by the margin coefficient, and the margin coefficient is greater than 1.

[0035] The implementation of the present invention has the following beneficial effects: the water-cooled air conditioning system increases the cooling load of the chiller by heating the cooling water through an external heating component, so that the chiller can get rid of the low-load operation condition, thereby ensuring that the chiller can operate stably. At the same time, the installation of the heating component does not require disassembly of the existing system, which can overcome the limitation that the existing system is difficult to add. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0037] Figure 1 is a simplified structural schematic diagram of a water-cooled air conditioning system of the present invention in some embodiments;

[0038] Figure 2 is a program flow chart of a control method applied to a water-cooled air conditioning system in some embodiments of the present invention;

[0039] Figure 3 It is a program flow chart of the control method of the present invention applied to a water-cooled air-conditioning system in other embodiments.

[0040] Reference numerals:

[0041] Air conditioning terminal device 1; chiller 2; evaporator 21; pipeline 3; return water pipeline 31; water supply pipeline 32; heating component 4; flow meter 51; first temperature sensor 52; second temperature sensor 53; third temperature sensor 54; controller 6; circuit switch 7; power supply component 8; photovoltaic power supply component 81; photovoltaic panel 811; photovoltaic power supply switch 812; photovoltaic power storage switch 813; energy storage power supply component 82; energy storage battery pack 821; energy storage power supply switch 822; grid power supply component 83; power access terminal 831; rectifier 832; grid power supply switch 833; grid power storage switch 834. DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0043] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0044] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0045] See also Figure 1 The present application constructs a water-cooled air-conditioning system, which may include an air-conditioning terminal device 1, a chiller 2, and a pipe 3 connected between the air-conditioning terminal device 1 and the chiller 2.

[0046] like Figure 1As shown, the pipeline 3 may include a return pipe 31 and a water supply pipe 32; one end of the return pipe 31 is connected to the water outlet of the air-conditioning terminal device 1, and the other end thereof is connected to the input end of the evaporator 21 of the chiller 2; one end of the supply pipe 32 is connected to the output end of the evaporator 21 of the chiller 2, and the other end thereof is connected to the water inlet end of the air-conditioning terminal device 1.

[0047] It can be understood that the high-temperature chilled water produced by the air-conditioning terminal device 1 can enter the evaporator 21 of the chiller 2 through the return pipe 31 to be cooled into low-temperature chilled water; then the low-temperature chilled water is supplied to the air-conditioning terminal device 1 through the water supply pipe 32, and the air-conditioning terminal device 1 absorbs heat and performs refrigeration; the low-temperature chilled water after absorbing heat is heated up to become high-temperature chilled water, and then enters the evaporator 21 through the return pipe 31 to be cooled; this cycle is repeated, which is the refrigeration process of the water-cooled air-conditioning system.

[0048] The water-cooled air conditioning system further comprises a heating assembly 4 installed on the water return pipe 31 , which is used to heat the chilled water in the water return pipe 31 to avoid low-load operation of the water chiller 2 .

[0049] It is understandable that the chiller 2 has a low load critical value Qx. When the water-cooled air-conditioning system is operating under low load conditions, and the cooling load of the chiller 2 is less than the low load critical value Qx, the chiller 2 will easily surge. However, the present application increases the real-time temperature of the high-temperature chilled water entering the chiller 2 by externally placing a heating component 4 on the return water pipeline 31, thereby increasing the cooling load of the chiller 2, ensuring that even if the water-cooled air-conditioning system is under low load conditions, the cooling load of the chiller 2 can be greater than the low load critical value Qx, thereby avoiding low load operation of the chiller 2.

[0050] It can be seen that the water-cooled air-conditioning system of the present application can effectively avoid the wear problem caused by the frequent start and stop of the traditional chiller 2, ensure the stable operation of the chiller 2 and the comfort of the air-conditioning terminal device 1, and also extend the service life of the chiller 2 in disguise. At the same time, for the chiller 2 which has built-in technology to cope with low-load conditions, the heating component 4 can serve as a second guarantee to prevent surge.

[0051] Secondly, the present application overcomes the problem of low-load operation of the chiller 2 by external means, so it can be adapted to various water-cooled air-conditioning systems without the need to dismantle and modify the old air-conditioning system, and it can also be added without affecting the operation of the air-conditioning system.

[0052] The heating component 4 can adopt a resistance heating method, which has the advantage of fast heating. Optionally, the heating component 4 can include a resistive structure with a certain resistance, and the resistive structure can be an electric heating wire, which is wound around the return pipe 31; the resistive structure can also be an electric heating rod, and one or more electric heating rods are arranged around the return pipe 31. The water-cooled air conditioning system also includes at least one power supply component 8 connected to the heating component 4, and the power supply component 8 can provide direct current to the resistive structure, so that the resistive structure is powered on and heated.

[0053] In this embodiment, if Figure 1 As shown, the heating assembly 4 includes an electric heating wire, which can be arranged on the side of the return pipe 31 close to the chiller 2, that is, with the midpoint of the return pipe 31 in the length direction as the boundary, the electric heating wire is arranged between the midpoint of the return pipe 31 and its end for connecting to the chiller 2, so as to heat the chilled water entering the chiller 2. The length of the electric heating wire can be adjusted according to factors such as the heating temperature, the heating speed, the flow rate, etc., which are not limited here. It can be supplemented here that the electric heating wire is easy to lay and can be directly installed on the return pipe 31 by winding. At the same time, the electric heating wire itself occupies very little space, and the installer only needs very little space during installation, which greatly reduces the demand for space.

[0054] In addition, in addition to the heating method of resistance power supply, the heating component 4 can also be heated by water heating, electromagnetic induction heating, photothermal heating, etc. For example, in an embodiment in which the heating component 4 is heated by water heating (this embodiment is not shown in the attached drawings), the heating component 4 may include a heat exchange pipeline arranged on one side of the return water pipeline 31, and hot water with a temperature higher than that of the high-temperature chilled water flows through the heat exchange pipeline to heat the high-temperature chilled water by the principle of heat exchange. For another example, in an embodiment in which the heating component 4 is heated by microwaves (this embodiment is not shown in the attached drawings), the return water pipeline 31 is a metal pipe, and the heating component 4 may include a coil sleeved on the outer periphery of the return water pipeline 31; by passing alternating current to the coil, the return water pipeline 31 will generate heat according to the principle of electromagnetic induction, thereby achieving the heating of the high-temperature chilled water.

[0055] In some embodiments, the heating component 4 can be configured to generate heat continuously during the operation of the chiller 2, that is, the heating component 4 is connected to a power source at the chiller 2, and the chiller 2 and the heating component 4 are started and stopped synchronously.

[0056] However, preferably, since the chiller 2 is not always operating under low-load conditions, continuous operation of the heating component 4 will result in greater energy consumption, and continuously heating the chilled water entering the chiller 2 will impose a greater burden on the chiller. Therefore, the water-cooled air-conditioning system may also include a monitoring component and a controller 6. The controller 6 is respectively connected to the monitoring component and the heating component 4. The monitoring component performs real-time detection of the circulation flow and temperature of the chilled water. The controller 6 determines whether the cooling load of the air-conditioning terminal device 1 is less than the low-load critical value Qx based on the data fed back by the monitoring component, and controls the working state of the heating component 4 based on the judgment result.

[0057] The working state of the heating component 4 includes an operating state indicating heating, and a shutdown state indicating standby or shutdown. The controller 6 can control the working state of the heating component 4 by controlling the on-off connection between the heating component 4 and the power supply component 8. The controller 6 can also control the working state of the heating component 4 by controlling whether the power supply component 8 is working or not. In this embodiment, a circuit switch 7 for controlling the on-off of the circuit is provided between the heating component 4 and the power supply component 8, and the circuit switch 7 is connected to the controller 6 to be controlled by the controller 6.

[0058] The monitoring component may include a flow meter 51, a first temperature sensor 52, a second temperature sensor 53 and a third temperature sensor 54. The flow meter 51 is used to monitor the circulation flow of the chilled water; it can be connected to the return water pipeline 31, such as a position on the return water pipeline 31 close to the air conditioning terminal device 1. The first temperature sensor 52 is used to monitor the temperature of the high-temperature chilled water output from the air conditioning terminal device 1; the first temperature sensor 52 can be connected to the upstream position of the heating component 4, such as a position on the return water pipeline 31 close to the air conditioning terminal device 1; the first temperature sensor 52 can be arranged adjacent to the flow meter 51. The second temperature sensor 53 is used to monitor the temperature of the high-temperature chilled water entering the chiller 2, and it can be connected to the downstream position of the heating component 4, such as connected to one end of the return water pipeline 31 for connecting to the chiller 2. The third temperature sensor 54 is used to monitor the temperature of the low-temperature chilled water after being cooled by the evaporator 21, and it can be connected to the downstream position of the evaporator 21, such as connected to one end of the water supply pipeline 32 for connecting to the chiller 2.

[0059] According to the data monitored in real time by the temperature measuring component, the controller 6 can obtain the cooling load of the air-conditioning terminal device 1 and the cooling load of the chiller 2 according to the following formula A. Formula A is expressed as:

[0060] Q=3600·c·F·ΔT

[0061] Wherein, Q is used to indicate cooling load, in kw; c is used to indicate specific heat capacity. This system uses water as the coolant, and the specific heat capacity of water is usually 4.186, in J / kg·℃; △T is used to indicate the change in cooling water temperature, in ℃; 3600 is the conversion factor for converting hours to seconds.

[0062] For the sake of convenience, the flow rate measured by the flow meter 51 is represented as F0, the temperature measured by the first temperature sensor 52 is represented as T1, the temperature measured by the second temperature sensor 53 is represented as T2, and the temperature measured by the third temperature sensor 54 is represented as T3; the cooling load of the air-conditioning terminal device 1 is defined as Q1, and the cooling load of the chiller 2 is defined as Q2.

[0063] Substituting parameters F0, T1 and T3 into formula A, the cooling load Q1 of the air-conditioning terminal device 1 can be obtained. Specifically:

[0064] Q1=1.163·F0·(T1―T3)

[0065] Substituting the parameters F0, T1 and T2 into formula A, the cooling load Q2 of chiller 2 can be obtained. Specifically:

[0066] Q2=1.163·F0·(T2―T3)

[0067] The control logic of the controller 6 can be: when the controller 6 detects that Q1 is less than Qx (low load critical value) and the heating component 4 is in the shutdown state, the circuit switch 7 can be closed to connect the heating component 4 and the power supply component 8. At this time, the heating component 4 heats the return pipe 31, so that T2 increases, thereby increasing Q2 to make it greater than Qx, thereby achieving the purpose of avoiding low-load operation of the chiller 2. When Q1 is greater than or equal to Qx, there is no need to heat to supplement the cold load. At this time, T1=T2, Q1=Q2. Secondly, when the controller 6 detects that Q2 is greater than or equal to Qx and the heating component 4 is in the heating state, the circuit switch 7 can be opened to disconnect the heating component 4 and the power supply component 8, so that the heating component 4 enters the shutdown state, thereby achieving the purpose of energy saving.

[0068] Preferably, a margin coefficient a can be added to the judgment condition for judging whether the heating component 4 is shut down, so as to further ensure that the chiller 2 can avoid low-load operation, that is, the controller 6 disconnects the circuit switch 7 only when it detects that Q2 is greater than aQx and the heating component 4 is in the heating state. a is used to represent the margin coefficient, and its value range can be (1.0, 1.1].

[0069] Looking at the power supply component 8 again, a single power supply component 8 can be one of the photovoltaic power supply component 81, the energy storage power supply component 82 and the grid power supply component 83.

[0070] For reference Figure 1 The photovoltaic power source assembly 81 may include a photovoltaic panel 811 and a photovoltaic power switch 812. The photovoltaic panel 811 may convert light energy into direct current; the photovoltaic power switch 812 is disposed at the connection circuit between the photovoltaic panel 811 and the heating assembly 4, and the photovoltaic power switch 812 is connected to the controller 6, and the controller 6 controls the on-off of the connection between the photovoltaic panel 811 and the heating assembly 4, thereby controlling whether the photovoltaic panel 811 supplies power to the heating assembly 4.

[0071] The energy storage power supply assembly 82 may include an energy storage battery pack 821 and an energy storage power switch 822. The energy storage battery pack 821 stores electrical energy and can output direct current; the energy storage power switch 822 is disposed at the connection circuit between the energy storage battery pack 821 and the heating assembly 4, and the energy storage power switch 822 is connected to the controller 6, and the controller 6 controls the on-off of the connection between the energy storage battery pack 821 and the heating assembly 4, thereby controlling whether the energy storage battery pack 821 supplies power to the heating assembly 4.

[0072] The grid power supply component 83 may include a power access terminal 831 for connecting to the mains, a rectifier 832 for rectifying AC power into DC power, and a grid power supply switch 833 arranged at the connection circuit between the rectifier 832 and the heating component 4; the grid power supply switch 833 is connected to the controller 6, and the controller 6 controls the on and off of the connection between the rectifier 832 and the heating component 4, thereby controlling whether the mains power supplies power to the heating component 4.

[0073] Optionally, the water-cooled air-conditioning system can simultaneously include a photovoltaic power supply component 81, an energy storage power supply component 82 and a grid power supply component 83; when the circuit switch 7 is closed, at least one of the photovoltaic power supply switch 812, the energy storage power supply switch 822 and the grid power supply switch 833 is closed synchronously to power the heating component 4.

[0074] It is understandable that when a single power supply component 8 meets the power of the heating component 4, only one of the photovoltaic power supply switch 812, the energy storage power supply switch 822 and the grid power supply switch 833 can be closed. If a single power supply component 8 cannot meet the power of the heating component 4, two or three of the photovoltaic power supply switch 812, the energy storage power supply switch 822 and the grid power supply switch 833 can be closed.

[0075] Further optionally, if Figure 1 As shown, the photovoltaic power component 81 is connected to the energy storage power component 82, and the photovoltaic power component 81 also includes a photovoltaic power storage switch 813, which is connected between the photovoltaic panel 811 and the energy storage battery group 821. By controlling the photovoltaic power storage switch 813 to be turned on or off by the controller 6, it is possible to control whether the photovoltaic panel 811 charges the energy storage battery group 821.

[0076] Similarly, the grid power component 83 is connected to the energy storage power component 82, and the grid power component 83 also includes a grid storage switch 834 connected between the rectifier 832 and the energy storage battery group 821. By controlling the on or off of the grid storage switch 834 by the controller 6, it is possible to control whether the mains charges the energy storage battery group 821.

[0077] The controller 6 can also access the network (not shown) to obtain the world time, and in the non-valley period of electricity price, the priority of photovoltaic power component 81> energy storage power component 82> grid power component 83 is used to power the heating component 4. Secondly, the controller 6 can also be set to control the grid power component 83 to charge the energy storage battery group 821 when the electricity price is valley at night and the cooling load of the air-conditioning terminal device 1 is not less than the low load critical value, until the energy storage battery group 821 is fully charged or needs to supply power to the heating component 4.

[0078] The controller 6 can also be connected to a light sensor (not shown). When there is sufficient sunlight and the cooling load of the air-conditioning terminal device 1 is not less than the low-load critical value, the photovoltaic power supply component 81 is controlled to charge the energy storage battery group 821 until the energy storage battery group 821 is fully charged or needs to supply power to the heating component 4.

[0079] It can be supplemented here that the photovoltaic power supply switch 812, the energy storage power supply switch 822, the grid power supply switch 833, the photovoltaic power storage switch 813, and the grid power storage switch 834 are not necessarily controlled by the controller 6. The water-cooled air conditioning system can also be provided with another controller, and these switches can also be connected to and controlled by another controller, which is not limited here.

[0080] In summary, the water-cooled air conditioning system uses an external heating component 4 and monitors the water temperature and flow rate between the air conditioning terminal device 1 and the chiller 2 to continuously determine whether the chiller 2 is in a low-load operating condition. When the chiller 2 is in a low-load operating condition, it timely intervenes to increase the cooling load of the chiller 2 by heating the cooling water, so that the chiller 2 can get rid of the low-load operating condition, thereby ensuring that the chiller 2 can operate safely and stably. At the same time, the installation of the heating component 4 does not require the disassembly of the existing system, which can overcome the limitation that the existing system is difficult to add.

[0081] Secondly, the water-cooled air-conditioning system can achieve energy saving and improve economic benefits by directly generating electricity and storing energy during the daytime using solar energy, and storing energy during the off-peak hours at night.

[0082] In addition, for the water-cooled air-conditioning system including the monitoring component and the controller 6, the present application also constructs a control method applied to the water-cooled air-conditioning system. Figure 2 , the control method may include the following steps:

[0083] S1: After the chiller 2 is started, the circulation flow data and temperature data of the chilled water are continuously obtained, wherein the temperature data includes the temperature data of the chilled water when it is output from the air-conditioning terminal device 1 and the temperature data of the chilled water after being cooled by the evaporator 21;

[0084] S2: deriving the cooling load Q1 of the air conditioning terminal device 1 according to the circulation flow data, the temperature data of the chilled water when it is output from the air conditioning terminal device 1, and the temperature data of the chilled water after being cooled by the evaporator 21;

[0085] S3: Determine the size between the cooling load Q1 of the air-conditioning terminal device 1 and the preset low load critical value Qx, and when it is determined that the cooling load Q1 of the air-conditioning terminal device 1 is less than the low load critical value Qx, control the heating component 4 to operate.

[0086] It can be understood that the circulation flow data of the chilled water can be collected by the flow meter 51. The installation position of the flow meter 51 can be referred to above and will not be described in detail here. Similarly, the temperature data of the chilled water when it is output from the air-conditioning terminal device 1 can be collected by the first temperature sensor 52, and the temperature data of the chilled water after being cooled by the evaporator 21 can be collected by the third temperature sensor 54. The installation positions of the first temperature sensor 52 and the third temperature sensor 54 can be referred to above and will not be described in detail here.

[0087] After the flow meter 51, the first temperature sensor 52 and the third temperature sensor 54 collect data, the controller 6 calculates the collected data according to the above formula A to obtain the cooling load Q1 of the air-conditioning terminal device 1. At the same time, the controller 6 compares the cooling load Q1 of the air-conditioning terminal device 1 with the preset low load critical value Qx, and controls the heating component 4 to work when it is determined that the cooling load Q1 of the air-conditioning terminal device 1 is less than the low load critical value Qx. Of course, if the heating component 4 is already working when it is determined that the cooling load Q1 of the air-conditioning terminal device 1 is less than the low load critical value Qx, the heating component 4 is kept working. If it is determined that the cooling load Q1 of the air-conditioning terminal device 1 is greater than the low load critical value Qx, the heating component 4 can continue to be kept on standby or the heating component 4 can be controlled to stop working.

[0088] Then, after executing step S3, step S1 may be re-executed, and the cycle is repeated until the chiller 2 stops working. Optionally, after the chiller 2 stops working, the controller 6 and the monitoring component may stop working synchronously to achieve energy saving.

[0089] It can be supplemented here that the low load critical value Qx of the chiller 2 can be set in advance in the controller 6 before the chiller 2 is started. For example, the relevant personnel determine the low load critical value Qx based on the historical data of the chiller 2 and input it into the controller 6.

[0090] Alternatively, reference may be made to Figure 3 In step S1, the temperature data may also include the temperature data of the chilled water when it enters the chiller 2; at the same time, after step S1, it also includes:

[0091] S25: The cooling load Q2 of the chiller 2 is obtained according to the circulation flow data, the temperature data of the chilled water when entering the chiller 2, and the temperature data of the chilled water after being cooled by the evaporator 21.

[0092] It can be explained that the temperature data of the chilled water when entering the chiller 2 can be collected by the second temperature sensor 53. The installation position of the second temperature sensor 53 can be referred to above and will not be described here. Subsequently, after the flow meter 51, the second temperature sensor 53 and the third temperature sensor 54 collect data, the controller 6 calculates the collected data according to the above formula A to obtain the cooling load Q2 of the chiller 2.

[0093] Correspondingly, step S3 may include the following sub-steps:

[0094] S31: Acquire the working state of the heating component 4, where the working state includes a running state and a shutdown state;

[0095] S32: when the heating component 4 is in the shutdown state, the magnitude between the cooling load Q1 of the air-conditioning terminal device 1 and the low load critical value Qx is determined, and when it is determined that the cooling load Q1 of the air-conditioning terminal device 1 is less than the low load critical value Qx, the heating component 4 is controlled to enter the running state;

[0096] S33: When the heating component 4 is in operation, the size between the cooling load Q2 of the chiller 2 and the low load critical value Qx is determined, and when it is determined that the cooling load Q2 of the chiller 2 is at least not less than the low load critical value Qx, the heating component 4 is controlled to enter the shutdown state.

[0097] It can be understood that in step S31, the controller 6 can determine the working state of the heating component 4 by receiving the level of the circuit feedback between the heating component 4 and the power supply component 8. For example, when the heating component 4 is connected to the power supply component 8, the controller 6 can receive a high level signal; when the heating component 4 is disconnected from the power supply component 8, the controller 6 can receive a low level signal.

[0098] In steps S32 and S33, according to the working state of the heating component 4, when the heating component 4 is in the standby state, Q1 and Qx are compared. When Q1 < Qx, the heating component 4 is heated, otherwise the heating component 4 is kept in the standby state; and when the heating component 4 is in the heating state, Q2 and Qx are compared. When Q2 is at least ≥ Qx, the heating component 4 stops heating, otherwise the heating component 4 stops working. It can be supplemented here that since the temperature adjustment of the air-conditioning terminal device 1 is uncontrollable, Q1 is prone to fluctuate. If the start and stop of the heating component 4 is controlled entirely by the size of Q1, the heating component 4 may switch between the running state and the shutdown state. At the same time, during actual operation, the values ​​of Q1 and Q2 will have certain delays and deviations (the deviations may be caused by the loss of cooling capacity due to insulation problems during the circulation of chilled water, measurement errors of sensors, etc.), and it takes a certain amount of time for the chiller 2 to start. Therefore, using Q1 as the judgment condition for the initial start of the heating component 4 can respond more promptly; if Q2 is used as the judgment condition for the initial start of the heating component 4, the chiller 2 may be in a state of frequent start and stop before the heating component 4 starts. Therefore, the method of selecting Q1 or Q2 as the judgment condition for the start / stop of the heating component 4 according to the working state of the heating component 4 can be more conducive to ensuring the stable operation of the chiller 2.

[0099] Preferably, in step S33, the judgment condition for stopping the heating component 4 also includes: if the cooling load Q2 of the chiller 2 is greater than or equal to the value of the low load critical value Qx multiplied by the margin coefficient a, that is, Q2 is at least ≥ aQx, then the heating component 4 is controlled to stop heating. It can be understood that adding the margin coefficient can further ensure that the chiller 2 can avoid low load operation; the margin coefficient is greater than 1, and the value range can be selected as (1.0, 1.1].

[0100] In summary, the control method applied to the water-cooled air-conditioning system determines whether the chiller 2 is in a low-load operating condition by real-time and continuous monitoring of the circulation flow data and temperature data of the chilled water, and when the chiller 2 is in a low-load operating condition, controls the heating component 4 to work, and intervenes in time to increase the cooling load Q2 of the chiller 2, so that the chiller 2 can get rid of the low-load operating condition, thereby ensuring that the chiller 2 can operate safely and stably.

[0101] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A water-cooled air conditioning system, It is characterized in that It comprises an air-conditioning terminal device (1), a water chiller (2), and a pipeline (3) connected between the air-conditioning terminal device (1) and the water chiller (2); The pipeline (3) comprises a water return pipeline (31) and a water supply pipeline (32); one end of the water return pipeline (31) is connected to the water outlet of the air conditioner terminal device (1), and the other end thereof is connected to the input end of the evaporator (21) of the chiller (2); one end of the water supply pipeline (32) is connected to the output end of the evaporator (21), and the other end thereof is connected to the water inlet of the air conditioner terminal device (1); The water-cooled air conditioning system further comprises a heating component (4) for heating the chilled water entering the evaporator (21); the heating component (4) is installed on the water return pipeline (31).

2. The water-cooled air conditioning system according to claim 1, It is characterized in that The water-cooled air conditioning system further comprises a monitoring component and a controller (6) connected to the monitoring component; the controller (6) is connected to the heating component (4) to switch the working state of the heating component (4) according to data collected by the monitoring component; The monitoring component comprises a flow meter (51) connected to the pipeline (3), a first temperature sensor (52) connected to the upstream position of the heating component (4), and a third temperature sensor (54) connected to the downstream position of the evaporator (21).

3. The water-cooled air conditioning system according to claim 2, It is characterized in that The monitoring component also includes a second temperature sensor (53) connected to a downstream position of the heating component (4).

4. The water-cooled air conditioning system according to claim 2 or 3, It is characterized in that The heating component (4) comprises an electric heating wire, and the electric heating wire is wound around the return water pipeline (31); The water-cooled air conditioning system further comprises at least one power supply component (8) connected to the heating component (4).

5. The water-cooled air conditioning system according to claim 4, It is characterized in that The single power supply component (8) is one of a photovoltaic power supply component (81), an energy storage power supply component (82) and a grid power supply component (83); The photovoltaic power supply component (81) comprises a photovoltaic panel (811) and a photovoltaic power supply switch (812); the photovoltaic panel (811) and the heating component (4) are provided with a connection circuit; and the photovoltaic power supply switch (812) is arranged at the connection circuit between the photovoltaic panel (811) and the heating component (4); The energy storage power supply component (82) comprises an energy storage battery group (821) and an energy storage power supply switch (822); the energy storage battery group (821) and the heating component (4) are provided with a connection circuit; and the energy storage power supply switch (822) is arranged at the connection circuit between the energy storage battery group (821) and the heating component (4); The grid power supply component (83) comprises a power supply access terminal (831) for accessing the mains, a rectifier (832) connected to the power supply access terminal (831), and a grid power supply switch (833); a connection circuit is provided between the rectifier (832) and the heating component (4), and the grid power supply switch (833) is arranged at the connection circuit between the rectifier (832) and the heating component (4).

6. The water-cooled air conditioning system according to claim 5, It is characterized in that The water-cooled air conditioning system comprises a photovoltaic power supply component (81), an energy storage power supply component (82) and a power grid power supply component (83); A connection circuit is provided between the photovoltaic panel (811) and the energy storage battery group (821), and the photovoltaic power supply component (81) further comprises a photovoltaic power storage switch (813) which is provided at the connection circuit between the photovoltaic panel (811) and the energy storage battery group (821); A connection circuit is provided between the rectifier (832) and the energy storage battery pack (821), and the grid power supply component (83) further includes a grid power storage switch (834) which is provided between the rectifier (832) and the energy storage battery pack (821).

7. A control method for a water-cooled air conditioning system according to any one of claims 2 to 6, It is characterized in that The control method comprises: S1: After the chiller (2) is started, the circulation flow data and temperature data of the chilled water are continuously obtained, wherein the temperature data includes the temperature data of the chilled water when it is output from the air-conditioning terminal device (1) and the temperature data of the chilled water after being cooled by the evaporator (21); S2: obtaining the cooling load of the air-conditioning terminal device (1) according to the circulation flow data, the temperature data of the chilled water when it is output from the air-conditioning terminal device (1), and the temperature data of the chilled water after being cooled by the evaporator (21); S3: Determine the difference between the cooling load of the air-conditioning terminal device (1) and a preset low-load critical value, and when it is determined that the cooling load of the air-conditioning terminal device (1) is less than the low-load critical value, control the heating component (4) to operate.

8. The control method of the water-cooled air conditioning system according to claim 7, It is characterized in that In step S1, the temperature data also includes temperature data when the chilled water enters the chiller (2); After step S1, the method further includes the following steps: S25: obtaining the cooling load of the water chiller (2) based on the circulation flow data, the temperature data of the chilled water when entering the water chiller (2), and the temperature data of the chilled water after being cooled by the evaporator (21); The step S3 comprises the following sub-steps: S31: Acquire the working state of the heating component (4), wherein the working state includes a running state and a shutdown state; S32: when the heating component (4) is in the shutdown state, determining the difference between the cooling load of the air-conditioning terminal device (1) and the low load critical value, and when determining that the cooling load of the air-conditioning terminal device (1) is less than the low load critical value, controlling the heating component (4) to enter the operating state; S33: When the heating component (4) is in operation, the difference between the cooling load of the chiller (2) and the low load critical value is determined, and when it is determined that the cooling load of the chiller (2) is at least not less than the low load critical value, the heating component (4) is controlled to enter a shutdown state.

9. The control method of the water-cooled air conditioning system according to claim 7 or 8, It is characterized in that In step S3, the cooling load is calculated according to the following formula: Q=3600·c·F·ΔT Among them, Q is used to represent the cooling load; c is used to represent the specific heat capacity; △T is used to represent the change in cooling water temperature; 3600 is the conversion factor for converting hours to seconds.

10. The control method of the water-cooled air conditioning system according to claim 8, It is characterized in that In step S33, the judgment condition for controlling the heating component (4) to enter the shutdown state also includes: the cooling load of the chiller (2) is greater than or equal to the value of the low load critical value multiplied by the margin coefficient, and the margin coefficient is greater than 1.

Images