A method, device and chiller unit for regulating water flow

Abstract

This invention discloses a water flow regulation method, device, and chiller unit. The method includes: when the chiller unit is under a preset ultra-low demand load, determining the current return water state of the chiller unit based on the evaporator inlet water temperature; if it is a constant temperature water source return water state, adjusting the water flow rate of the mixing circuit based on the evaporator outlet water temperature and evaporation pressure according to a first strategy; if it is a non-constant temperature water source return water state, adjusting the water flow rate of the mixing circuit based on the evaporator outlet water temperature according to a second strategy. Through this invention, when the chiller unit is under a preset ultra-low demand load, different return water schemes are distinguished based on the evaporator inlet water temperature, and the water flow rate of the mixing circuit is adjusted to ensure the normal operation of the unit under extremely low load conditions, avoiding the unit's standby problem under low demand load conditions. By using a low water flow rate combined with a mixing scheme, the stable operation of the unit under ultra-low load conditions is ensured.

Description

Technical Field

[0001] This invention relates to the field of chiller technology, and more specifically, to a water flow regulation method, device, and chiller. Background Technology

[0002] Currently, conventional chiller units typically use a constant water flow rate to produce chilled water. However, in actual engineering applications, when the actual load demand of the chiller unit is too low, the constant water flow rate can easily cause the unit to go into standby mode, affecting the operation of the project. When the actual load demand of the chiller unit is too high, it is difficult to meet the needs of customers.

[0003] There is currently no effective solution to the problem of generator units easily going into standby mode under low demand load conditions in existing technologies. Summary of the Invention

[0004] This invention provides a water flow regulation method, device, and chiller unit to solve the problem of unit standby easily caused under low demand load conditions in the prior art.

[0005] To address the aforementioned technical problems, this invention provides a water flow rate adjustment method, comprising: when the chiller unit is under a preset ultra-low demand load, determining the current return water state of the chiller unit based on the evaporator inlet water temperature; if it is a constant temperature water source return water state, adjusting the water flow rate of the mixing circuit based on the evaporator outlet water temperature and evaporation pressure according to a first strategy; if it is a non-constant temperature water source return water state, adjusting the water flow rate of the mixing circuit based on the evaporator outlet water temperature according to a second strategy; wherein the mixing circuit is a bypass pipe from the evaporator inlet to the outlet.

[0006] Furthermore, the chiller unit is considered to be under a preset ultra-low demand load when the water flow rate of the chiller unit drops to 50% of the rated water flow rate L.

[0007] Furthermore, the current return water status of the chiller unit is determined based on the evaporator inlet water temperature, including:

[0008] The rate of change ΔT0 per minute of the inlet water temperature T0 is measured within a preset time period before the water flow rate of the chiller unit drops to 50% of the rated water flow rate L.

[0009] Determine whether all ΔT0 ≥ -k1; where k1 is a preset value;

[0010] If so, then the current return water status of the chiller unit is determined to be constant temperature water source return water status;

[0011] If not, then the current return water status of the chiller unit is determined to be a non-constant temperature water source return water status.

[0012] Furthermore, if it is a constant temperature water source return state, then based on the first strategy, the water flow rate of the mixing circuit is adjusted according to the evaporator outlet water temperature and evaporation pressure, including:

[0013] The rate of change ΔT1 per minute of the outlet water temperature T1 is measured within a preset time period before the water flow rate of the chiller unit drops to 50% of the rated water flow rate L.

[0014] Determine whether all ΔT1 ≤ -k2;

[0015] If so, the mixing solenoid valve is opened, and the mixing auxiliary water pump is opened to increase the water flow of the chiller unit by a%*L / min until T1<T-k3, at which point the increase in the water flow of the chiller unit is stopped.

[0016] If not, control the mixing solenoid valve to open, control the mixing auxiliary water pump to open, and adjust the water flow rate of the mixing circuit to b%*rated water flow rate L; where a and b are preset values, and k1, k2, and k3 are preset values; then, increase or stop increasing the water flow rate of the mixing circuit according to the outlet water temperature T1 and the evaporation pressure P.

[0017] The mixing circuit is equipped with the mixing solenoid valve and the mixing auxiliary water pump.

[0018] Further, increasing or stopping the increase of the water flow rate in the mixing channel based on the outlet water temperature T1 and the evaporation pressure P includes:

[0019] Determine whether the outlet water temperature T1 satisfies: T1≤T-k4; where T is the preset required temperature and k4 is the preset value;

[0020] If so, the opening of the throttling device is increased, and the water flow rate in the mixing circuit continues to increase by c%*L; where c is a preset value; at the same time, the water flow rate in the mixing circuit is controlled according to the evaporation pressure to avoid the chiller unit from shutting down due to low pressure protection.

[0021] If not, then stop increasing the water flow in the mixing channel.

[0022] Furthermore, the water flow rate in the mixing circuit is controlled based on the evaporation pressure to prevent the chiller unit from shutting down due to low pressure protection, including:

[0023] Detect the evaporation pressure P of the evaporator;

[0024] Determine if the following condition is met: P ≥ evaporation pressure protection value P 保 ;

[0025] If so, return to determine whether the outlet water temperature T1 satisfies: T1≤T-k4;

[0026] If not, the throttling device will remain open until P ≥ P. 保 During this period, stop increasing the water flow in the mixing channel;

[0027] The throttling device is installed on the pipeline between the condenser and the evaporator.

[0028] Furthermore, the method also includes:

[0029] During the process of adjusting the water flow rate of the mixing circuit based on the outlet water temperature and evaporation pressure of the evaporator according to the first strategy, if the actual demand load of the chiller unit increases, the mixing auxiliary water pump will be shut down.

[0030] Furthermore, if the water source is not at a constant temperature, the water flow rate in the mixing circuit is adjusted based on the evaporator's outlet water temperature according to the second strategy, including:

[0031] Control the opening of the mixing solenoid valve;

[0032] Turn on the mixing auxiliary water pump;

[0033] Increase the water flow rate of the chiller unit by a%*L / min until T1 < T-k3, then stop increasing the water flow rate of the chiller unit.

[0034] Where a is a preset value, k3 is a preset value, and the mixing water circuit is equipped with the mixing solenoid valve and the mixing water auxiliary pump.

[0035] Furthermore, the method also includes:

[0036] In the process of adjusting the water flow rate of the mixing circuit based on the outlet water temperature of the evaporator according to the second strategy, if the actual demand load of the chiller unit increases, the water flow rate of the chiller unit will be reduced by a%*L / min.

[0037] Furthermore, before the chiller unit reaches a preset ultra-low demand load, the method further includes:

[0038] When the chiller unit is under preset low demand load, the water flow rate of the chiller unit is adjusted according to the inlet and outlet water temperatures of the evaporator.

[0039] Furthermore, the chiller unit is operating at a preset low demand load, including:

[0040] After the chiller unit starts cooling operation, if the load decreases until it is unloaded to the preset minimum operating load, then the chiller unit is determined to be at the preset low demand load.

[0041] Furthermore, the water flow rate of the chiller unit is adjusted according to the inlet and outlet water temperatures of the evaporator, including:

[0042] Determine whether the following condition is met continuously within time t: outlet water temperature T1 ≤ T - k2; where T is the preset required temperature and k2 is the preset value;

[0043] If so, adjust the water flow rate of the chiller unit according to the inlet water temperature T0 of the evaporator;

[0044] If not, maintain the current state and do not adjust the water flow rate of the chiller unit.

[0045] Furthermore, the water flow rate of the chiller unit is adjusted according to the inlet water temperature T0 of the evaporator, including:

[0046] Calculate (T-T1) / (T0-T1)=m%;

[0047] Reduce the water flow rate of the chiller unit by m% * rated water flow rate (L);

[0048] Then return to the execution steps: determine whether the following condition is met continuously within time t: outlet water temperature T1≤T-k2; until the water flow rate of the chiller unit drops to 50% of L, then it is determined that the chiller unit is under the preset ultra-low demand load.

[0049] Furthermore, the method also includes:

[0050] When the chiller unit is at a preset low demand load, during the process of adjusting the chiller unit's water flow rate according to the evaporator's inlet and outlet water temperatures, if the actual demand load of the chiller unit increases, the chiller unit's water flow rate is increased to the rated water flow rate L by an increment of c%*L / min, and then the chiller unit loading operation is executed; where c is a preset value.

[0051] Furthermore, the method also includes:

[0052] When the chiller unit is under preset high demand load, the water flow rate of the chiller unit is adjusted according to the changes in operating load and the outlet water temperature of the evaporator.

[0053] Furthermore, the chiller unit is operating at a preset high demand load, including:

[0054] When the chiller unit is running stably at its rated water flow rate L, the operating load Q of the chiller unit is detected.

[0055] Determine whether Q≥X%. If so, determine that the chiller unit is under the preset high demand load; where X is the preset value.

[0056] Furthermore, the water flow rate of the chiller unit is adjusted according to changes in operating load and the outlet water temperature of the evaporator, including:

[0057] Detect the change in operating load within a preset time period t: ΔQ = Q tmin -Q0; where Q tminQ0 is the operating load at the end of time t, and Q0 is the initial operating load.

[0058] Determine whether the following condition is met: ΔQ≥A; where A is the load change limit.

[0059] If so, the water flow rate of the chiller unit is increased by c%*rated water flow rate L, where c is a preset value; at the same time, the operating load of the chiller unit is checked to see if it is already fully loaded. If the chiller unit has not been loaded to full load, the load is continued; if it is already fully loaded, the water flow rate of the chiller unit is adjusted according to the outlet water temperature.

[0060] If not, there is no need to adjust the water flow rate of the chiller unit; it can continue to operate stably at the rated water flow rate L.

[0061] Furthermore, if the unit is already fully loaded, the water flow rate of the chiller unit will be adjusted according to the outlet water temperature, including:

[0062] Determine whether the outlet water temperature T1 satisfies: T1≥T+k2; where T is the preset required temperature and k2 is the preset value;

[0063] If so, increase the water flow rate of the chiller unit by a%*L / min until T1<T+k2, then stop increasing the water flow rate of the chiller unit.

[0064] If not, then do not adjust the water flow rate of the chiller unit.

[0065] The present invention also provides a water flow regulating device, wherein the device comprises:

[0066] The judgment module is used to determine the current return water status of the chiller unit based on the inlet water temperature of the evaporator when the chiller unit is under a preset ultra-low demand load.

[0067] The first processing module is used to adjust the water flow rate of the mixing circuit based on the outlet water temperature and evaporation pressure of the evaporator under the constant temperature water source return state.

[0068] The second processing module is used to adjust the water flow rate of the mixing circuit based on the outlet water temperature of the evaporator in the case of non-constant temperature water source return water.

[0069] The mixing water path is a bypass pipe from the inlet of the evaporator to the outlet.

[0070] The present invention also provides a water chiller unit, wherein the water chiller unit includes a compressor, a condenser, a throttling device, and an evaporator connected in sequence, a mixing water circuit from the inlet of the evaporator to the outlet, and the aforementioned water flow regulating device.

[0071] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the method as described above.

[0072] By applying the technical solution of this invention, when the chiller unit is under a preset ultra-low demand load, different return water schemes are distinguished according to the inlet water temperature of the evaporator, and the water flow rate of the mixing circuit is adjusted to ensure the normal operation of the unit under extremely low load and avoid the unit standby problem under low demand load conditions. The low water flow rate combined with the mixing scheme ensures stable operation of the unit under ultra-low load conditions. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of the structure of a chiller unit according to an embodiment of the present invention;

[0074] Figure 2 This is a flowchart of a water flow rate adjustment method according to an embodiment of the present invention;

[0075] Figure 3 This is a flowchart of an ultra-low demand load mixing control method according to an embodiment of the present invention;

[0076] Figure 4 This is a flowchart of a low-demand load mixing control method according to an embodiment of the present invention;

[0077] Figure 5 This is a flowchart of a high-demand load mixing control method according to an embodiment of the present invention;

[0078] Figure 6 This is a structural block diagram of a water flow regulating device according to an embodiment of the present invention. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0080] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0081] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0082] It should be understood that although the terms first, second, third, etc., may be used to describe strategies in the embodiments of the present invention, these strategies should not be limited to these terms. These terms are only used to distinguish strategies. For example, without departing from the scope of the embodiments of the present invention, a first strategy may also be referred to as a second strategy, and similarly, a second strategy may also be referred to as a first strategy.

[0083] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0084] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0085] The optional embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0086] Example 1

[0087] According to an embodiment of the present invention, a method for regulating water flow is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0088] Figure 1 This is a structural schematic diagram of a chiller unit according to an embodiment of the present invention, as shown below. Figure 1As shown, the chiller unit includes a compressor 1, a condenser 2, a throttling device 3, and an evaporator 4 connected in sequence. The mixing circuit runs from the inlet of the evaporator 4 through a bypass pipe to the outlet. The mixing circuit is equipped with a mixing auxiliary water pump 6 and a mixing solenoid valve 7.

[0089] The water flow regulation scheme of the present invention is based on the above-mentioned chiller unit. Figure 2 This is a flowchart of a water flow rate adjustment method according to an embodiment of the present invention, such as... Figure 2 As shown, the method includes the following steps:

[0090] Step S201: When the chiller unit is under a preset ultra-low demand load, determine the current return water status of the chiller unit based on the inlet water temperature of the evaporator.

[0091] Specifically, the rate of change ΔT0 of the inlet water temperature T0 per minute is detected within a preset time period before the water flow rate of the chiller unit drops to 50% of the rated water flow rate L; it is then determined whether all ΔT0 values ​​are ≥ -k1, where k1 is a preset value; if yes, the current return water state of the chiller unit is determined to be a non-constant temperature water source return water state; if no, the current return water state of the chiller unit is determined to be a constant temperature water source return water state.

[0092] Step S202: If it is a constant temperature water source return state, then adjust the water flow of the mixing circuit according to the outlet water temperature and evaporation pressure of the evaporator based on the first strategy.

[0093] In step S203, if the water source is not in a constant temperature return state, the water flow rate of the mixing circuit is adjusted according to the outlet water temperature of the evaporator based on the second strategy.

[0094] Based on the control scheme of this embodiment, when the chiller unit is under a preset ultra-low demand load, different return water schemes are distinguished according to the evaporator inlet water temperature, and the water flow rate of the mixing circuit is adjusted to ensure the normal operation of the unit under extremely low load and avoid the unit standby problem under low demand load conditions. The low water flow rate combined with the mixing scheme ensures stable operation of the unit under ultra-low load conditions.

[0095] It should be noted that if the water flow rate of the chiller unit drops to 50% of the rated water flow rate L, the chiller unit is considered to be under preset ultra-low demand load. The water flow rate of the chiller unit is detected at the inlet of the evaporator.

[0096] The following is a detailed description of step S202:

[0097] If it is a constant-temperature water source return state, meaning the actual water output of the unit is consumed and not circulated back to the unit, and the actual water intake of the unit is constant-temperature groundwater, then based on the first strategy, the water flow rate of the mixing circuit is adjusted according to the evaporator outlet water temperature and evaporation pressure, including:

[0098] 1) Detect the rate of change ΔT1 of the outlet water temperature T1 per minute within a preset time period before the water flow rate of the chiller unit drops to 50% of the rated water flow rate L;

[0099] 2) Determine whether all ΔT1 ≤ -k2 (k2 can take the value 0.5);

[0100] 3) If so, it means that the actual demand load is close to the unit output. Control the mixing solenoid valve to open and control the mixing auxiliary water pump to open, increasing the water flow of the chiller unit by a%*L / min until T1<T-k3, then stop increasing the water flow of the chiller unit.

[0101] 4) If not, control the mixing solenoid valve to open, control the mixing auxiliary water pump to open, and adjust the water flow rate of the mixing circuit to b% * rated water flow rate L; where a and b are preset values, and k1, k2, and k3 are preset values; then, increase or stop increasing the water flow rate of the mixing circuit according to the outlet water temperature T1 and the evaporation pressure P:

[0102] 41) Determine whether the outlet water temperature T1 satisfies: T1≤T-k4 (k4 can take the value 0.3); where T is the preset required temperature and k4 is the preset value;

[0103] 42) If so, increase the opening of the throttling device by n% (the opening of the throttling device is increased to ensure the evaporation pressure P, so n can be adjusted to a larger value; the value of n can be set to 5%~10%), and continue to increase the water flow rate in the mixing circuit by c%*L; where c is a preset value; at the same time, control the water flow rate in the mixing circuit according to the evaporation pressure to avoid low-pressure protection shutdown of the chiller unit, specifically including:

[0104] Detect the evaporation pressure P of the evaporator; determine if the following condition is met: P ≥ evaporation pressure protection value P 保 If yes, then return to determine if the outlet water temperature T1 satisfies: T1≤T-k4; if no, then control the throttling device to remain open until P≥P is satisfied. 保 During this period, the water flow rate in the mixing circuit is stopped; the throttling device is installed on the pipeline between the condenser and the evaporator.

[0105] If P < P 保 If the pressure is already below the set protection value, the unit is very likely to experience other malfunctions due to the excessively low evaporation pressure, leading to standby. In this case, stop adjusting the water flow rate and continuously increase the opening of the throttling device (the evaporation pressure P will increase) until P ≥ P 保 The unit then maintained its current operating status.

[0106] P 保This is the set evaporation pressure protection value. This value is settable, and the protection value setting varies depending on the type of chiller unit. For conventional screw chiller models, the setting value is generally between 200 kPa and 300 kPa.

[0107] 43) If not, it means that the actual outlet water temperature is close to the set temperature and no adjustment is needed. Maintain the current state of operation and stop increasing the water flow of the mixing circuit.

[0108] It should be noted that, in the process of adjusting the water flow rate of the mixing circuit based on the outlet water temperature and evaporation pressure of the evaporator according to the first strategy, if the actual demand load of the chiller unit increases, the mixing auxiliary water pump will be shut down first.

[0109] The following is a detailed description of step S203:

[0110] If the water source is not at a constant temperature, the second strategy is used to adjust the water flow rate in the mixing circuit based on the evaporator's outlet water temperature, including:

[0111] 1) Control the opening of the mixing solenoid valve; control the opening of the mixing auxiliary water pump;

[0112] 2) Increase the water flow rate of the chiller unit by a%*L / min until T1<T-k3, then stop increasing the water flow rate of the chiller unit; where a is a preset value, k3 is a preset value, and a mixing solenoid valve and a mixing auxiliary water pump are installed on the mixing circuit.

[0113] The water flow rate in the mixing circuit should not exceed 25% of the rated water flow rate L to ensure sufficient water flow in the evaporator and to ensure that the unit does not stop.

[0114] It should be noted that, in the process of adjusting the water flow rate of the mixing circuit based on the outlet water temperature of the evaporator according to the second strategy, if the actual demand load of the chiller unit increases, the water flow rate of the chiller unit will be reduced by a%*L / min.

[0115] In this embodiment, when the chiller unit is under ultra-low demand load, different return water schemes are distinguished, the water flow is adjusted, and mixing control is added to ensure that the unit operates under extremely low load.

[0116] In addition, when the chiller unit is under a preset low demand load, this embodiment can adjust the water flow rate of the chiller unit according to the inlet and outlet water temperatures of the evaporator. The condition for determining the preset low demand load is: after the chiller unit starts cooling operation, the load decreases until it is unloaded to the preset minimum operating load, then the chiller unit is determined to be under a preset low demand load.

[0117] The following is a detailed introduction.

[0118] 1) Determine if the following condition is met continuously within time t: outlet water temperature T1 ≤ T - k2 (k2 can be 0.3); where T is the preset required temperature and k2 is the preset value; when considering the magnitude of t, 3min ≤ t ≤ 10min is used to avoid inaccuracies due to too short a time and to avoid unit standby due to too long a time. 0.3 is set to account for deviations in water temperature detection, so T1 ≤ T - 0.3 is used to avoid the impact of small fluctuations in water temperature or detection deviations on unit control.

[0119] 2) If so, adjust the water flow rate of the chiller unit according to the inlet water temperature T0 of the evaporator;

[0120] Specifically, calculate (T-T1) / (T0-T1)=m%; control the water flow rate of the chiller unit to decrease by m%*rated water flow rate L; then return to step 1: determine whether the following condition is met within consecutive time t: outlet water temperature T1≤T-k2; until the water flow rate of the chiller unit drops to 50% of L, then determine that the chiller unit is under the preset ultra-low demand load.

[0121] 3) If not, maintain the current state and do not adjust the water flow rate of the chiller unit.

[0122] It should be noted that when the chiller unit is at the preset low demand load, during the process of adjusting the water flow rate of the chiller unit according to the inlet and outlet water temperatures of the evaporator, if the actual demand load of the chiller unit increases, the water flow rate of the chiller unit will be increased to the rated water flow rate L by an increment of c%*L / min, and then the chiller unit loading operation will be executed; where c is the preset value.

[0123] In this embodiment, when the chiller unit is under ultra-low demand load, different return water schemes are distinguished, the water flow is adjusted, and mixing control is added to ensure that the unit operates under extremely low load.

[0124] When the chiller unit is under a preset high demand load, the embodiment can adjust the water flow rate of the chiller unit according to changes in the operating load and the outlet water temperature of the evaporator. The condition for determining the preset high demand load is: when the chiller unit is running stably at the rated water flow rate L, the operating load Q of the chiller unit is detected; it is determined whether Q ≥ X%. If it does, the chiller unit is determined to be under the preset high demand load; where X is a preset value.

[0125] The following is a detailed introduction.

[0126] 1) Detect the change in operating load within a preset time period t: ΔQ = Q tmin -Q0; where Q tmin Q0 is the operating load at the end of time t, and Q0 is the initial operating load.

[0127] When considering the value of t, 5min≤t≤10min, the load change is not obvious for too long a time, but for too long a time, it will be affected by other factors such as ambient temperature and frequently enter this control state.

[0128] 2) Determine whether the following condition is met: ΔQ≥A; where A is the load change limit.

[0129] 3) If so, increase the water flow rate of the chiller unit by c% * rated water flow rate L, where c is a preset value; simultaneously, check if the chiller unit is already at full load. If the chiller unit is not yet at full load, continue loading; if it is already at full load, adjust the water flow rate of the chiller unit according to the outlet water temperature, specifically including:

[0130] Determine if the outlet water temperature T1 meets the following condition: T1≥T+k2 (k2 can be 0.3); where T is the preset required temperature and k2 is the preset value; if yes, it is considered that the actual demand is large at this time, and the water flow rate of the chiller unit is increased by a%*L / min until T1<T+k2, at which point the increase in the water flow rate of the chiller unit is stopped; if no, it is considered that the unit can meet the actual demand at this time, and the status quo is maintained without adjusting the water flow rate of the chiller unit.

[0131] The maximum water flow rate of the unit is increased to 130%L. Excessive water flow rate will reduce the temperature difference between the inlet and outlet water, affecting actual use.

[0132] 4) If not, it means that the unit is already operating close to the actual demand and there is no need to adjust the water flow of the chiller unit. Continue to operate stably at the rated water flow L.

[0133] In this embodiment, when the chiller unit is under high demand load, the unit load operation and changes in inlet and outlet water temperature are detected to pre-increase the unit water flow rate to meet the actual demand.

[0134] The variable water flow and mixing control scheme proposed in this embodiment gradually adjusts the water flow based on the deviation of the inlet water temperature from the preset value to control the unit load while ensuring uninterrupted unit operation. It controls the operation of the mixing circuit by detecting the rate of change of inlet and outlet water temperatures, further expanding the unit's operating range. It also proactively adjusts the water flow to meet high-demand loads by detecting water temperature changes. Under excessively high loads, the water flow is increased to meet customer needs, while under excessively low loads, the water flow is reduced and mixing is implemented to ensure unit operation. This solves the problem of unit standby under low-demand load conditions and the problem of the unit failing to meet usage requirements under high-demand load conditions.

[0135] Example 2

[0136] The following section introduces the unit control scheme for the preset ultra-low demand load. Figure 3This is a flowchart of the ultra-low demand load mixing control method according to an embodiment of the present invention, such as... Figure 3 As shown, it includes at least the following steps:

[0137] Step S301, detect the rate of change ΔT0 of T0 per minute within the 10 minutes before the water flow rate drops to 50%, ΔT0 = (T 0，1min -T0).

[0138] ΔT 0，1min T0 represents the temperature after 1 minute, and T0 represents the temperature at the beginning of that minute. The rate of change per minute (ΔT0) is calculated by subtracting the initial temperature from the final temperature of each minute. If all ΔT0 values ​​are ≥ -0.1, the unit's inlet water is determined to be constant-temperature groundwater return water (i.e., the actual water output from the unit is consumed and not circulated back into the unit; the actual inlet water is constant-temperature groundwater), and the process proceeds to step S302. If any ΔT0 < 0.1, the unit's inlet water is determined to be non-constant-temperature groundwater return water (non-constant-temperature groundwater includes engineering water), and the process proceeds to step S303.

[0139] Step S302, detect the rate of change of T1 per minute ΔT1 (ΔT1 = T) during the 10 minutes before the water flow rate drops to 50%. 1，1min If all ΔT1 are ≤ -0.5 (then it is determined that the actual demand load is close to the unit output), then proceed to step S303;

[0140] Otherwise, open the mixing solenoid valve 7, open the mixing auxiliary water pump 6, and control the water flow in the mixing circuit to 25% of the rated water flow L.

[0141] Next, ① check if the actual outlet water temperature T1≤T-0.3. If not, it means that the actual outlet water temperature is close to the set temperature and no adjustment is needed. Maintain the current state of operation.

[0142] ② If T1≤T-0.3, first control the throttling device (main valve) to open by n% (the throttling device is opened to ensure the evaporation pressure P, so n can be adjusted to be larger, and the value of n can be set to 5%~10%), then control the water flow rate of the mixing circuit to increase by 2%L, and simultaneously check whether the pressure P of the evaporator heat exchanger 4 is ≥P 保 (P 保 To set the evaporation pressure protection value, this value is settable. The protection value setting varies depending on the type of chiller unit. For conventional screw chiller models, the setting value is generally between 200 kPa and 300 kPa.

[0143] ③If P≥P 保 If the temperature is T1≤T-0.3, then return to step ② until the outlet water temperature T1≤T-0.3 or P<P. 保 ;

[0144] ④ If P < P 保 If the pressure is already below the set protection value, the unit is very likely to experience other malfunctions due to the excessively low evaporation pressure, leading to standby. In this case, stop adjusting the water flow rate and continuously increase the opening of the throttling device (pressure P will increase) until P ≥ P 保 The unit then maintained its current operating status.

[0145] If the actual demand load of the chiller unit increases during the above control process, the mixing auxiliary water pump 6 should be shut down first.

[0146] Step S303: Control the water flow rate of the mixing circuit to increase by 2% L / min (the water flow rate of the mixing circuit shall not exceed 25% of the rated water flow rate to ensure sufficient water flow in the evaporator and ensure that the unit does not stop). Simultaneously determine T1≤T-0.3. If not, stop increasing the water flow rate of the mixing circuit. If the actual demand load of the chiller unit increases during this process, reduce the water flow rate of the mixing circuit by 2% L / min.

[0147] In this embodiment, when the chiller unit is under ultra-low demand load, different return water schemes are distinguished, the water flow is adjusted, and mixing control is added to ensure that the unit operates under extremely low load.

[0148] Example 3

[0149] The following section introduces the unit control scheme for the preset low demand load. Figure 4 This is a flowchart of a low-demand load mixing control method according to an embodiment of the present invention, such as... Figure 4 As shown, it includes at least the following steps:

[0150] Step S401: During the cooling operation of the unit, if the actual demand load decreases, that is, the outlet water temperature detection point T1 is lower than the preset outlet water temperature T-1, the unit will perform an unloading operation.

[0151] Step S402: When the unit is unloaded to the minimum operating load, if the continuous time t (3min≤t≤10min, to avoid inaccuracy due to too short a time and to avoid the unit being idle due to too long a time) T1 is less than or equal to (T-0.3) (0.3 is set to T1≤T-0.3 to avoid the unit control being affected by small fluctuations in water temperature or detection deviations), then calculate (T-T1) / (T0-T1)=m% (m>50, then calculate with 50). At this time, control the water flow rate of the chiller unit to decrease by m% of the rated water flow rate L.

[0152] In step S403, after reducing the water flow rate, the detection in step S402 is performed again until the water flow rate drops to 50% of the rated water flow rate L. If the water flow rate drops to 50% and the time interval T1 ≤ T-0.3 is continuous for t, then the ultra-low demand load mixing control is entered.

[0153] In this control scheme, if the actual demand load increases, the water flow rate is gradually increased to the rated water flow rate L in increments of 1% L / min before the unit is loaded.

[0154] In this embodiment, when the chiller unit is under low demand load, the water flow rate is gradually reduced by detecting the inlet and outlet water temperatures and the preset outlet water temperature, as well as the changes in the inlet water temperature, so as to meet the actual demand and ensure the operation of the chiller unit.

[0155] Example 4

[0156] The following section introduces the unit control scheme for pre-set high demand load conditions. Figure 5 This is a flowchart of a high-demand load mixing control method according to an embodiment of the present invention. The high-demand load mixing control method is a joint adjustment of water flow rate and unit operating load, such as... Figure 5 As shown, it includes at least the following steps:

[0157] In step S501, during stable operation of the unit, it is determined whether the unit's operating load Q is ≥75%. If not, the actual demand is relatively small, and the unit can meet the demand by operating normally at the rated water flow rate without adjustment.

[0158] Step S502: If the operating load Q ≥ 75%, then detect the load change of the unit within time t (5 min ≤ t ≤ 10 min; load changes are not obvious over long periods, and frequent entry into this control will be due to the influence of other factors such as ambient temperature) ΔQ = Q. tmin -Q0, and compare ΔQ with the load limit change value A. If ΔQ < A, it is determined that the unit is operating close to the actual demand at this time, and there is no need to adjust the water flow.

[0159] Step S503: If ΔQ≥A, increase the unit water flow rate by 5%L; simultaneously determine whether the unit operating load is already at full load, i.e., 100%. If the unit has not yet reached full load, the unit continues to load.

[0160] Step S504: When the unit has reached 100% load, the actual output water T1 and the preset output water T are detected and compared. If T1 < T + 0.3, it is determined that the unit can meet the actual demand and the status quo is maintained without adjustment. If T1 ≥ T + 0.3, it is determined that the actual demand is large and the water flow rate is increased by 2% L / min until T1 < T + 0.3 (the unit water flow rate can be increased to a maximum of 130% L. Excessive water flow rate will reduce the temperature difference between the inlet and outlet water and affect actual use).

[0161] In this embodiment, when the chiller unit is under high demand load, the unit load operation and changes in inlet and outlet water temperature are detected to pre-increase the unit water flow rate to meet the actual demand.

[0162] Example 5

[0163] Corresponding to Figure 2 The water flow regulation method described herein is illustrated in this embodiment, which provides a water flow regulation device, such as... Figure 6 The diagram shown illustrates the structure of a water flow regulating device, which includes:

[0164] The judgment module 10 is used to determine the current return water status of the chiller unit based on the inlet water temperature of the evaporator when the chiller unit is under a preset ultra-low demand load.

[0165] The first processing module 20 is connected to the judgment module 10 and is used to adjust the water flow of the mixing circuit according to the outlet water temperature and evaporation pressure of the evaporator under the constant temperature water source return state.

[0166] The second processing module 30 is connected to the judgment module 10 and is used to adjust the water flow rate of the mixing circuit according to the outlet water temperature of the evaporator based on the second strategy when the water source is not at constant temperature.

[0167] Among them, the mixing water circuit is the bypass pipe from the inlet of the evaporator to the outlet.

[0168] This embodiment changes the inlet water flow rate of the chiller unit to meet high load demands with high water flow rate and meet customer needs with low water flow rate while ensuring normal unit operation. It also uses a low water flow rate plus mixing scheme to ensure stable unit operation under ultra-low load conditions.

[0169] This embodiment also provides a water chiller unit, which includes a compressor, a condenser, a throttling device, and an evaporator connected in sequence, a mixing water circuit from the inlet of the evaporator to the outlet, and the aforementioned water flow regulating device.

[0170] Example 6

[0171] This invention provides software for executing the technical solutions described in the above embodiments and preferred embodiments.

[0172] This invention provides a non-volatile computer storage medium storing computer-executable instructions that can execute the water flow regulation method in any of the above-described method embodiments.

[0173] The aforementioned storage medium stores the aforementioned software, and the storage medium includes, but is not limited to, optical discs, floppy disks, hard disks, and rewritable memory.

[0174] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0175] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0176] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0177] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0178] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0179] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0180] The above-described product can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.

[0181] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0182] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0183] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for regulating water flow, characterized in that, The method includes: When the chiller unit is under the preset ultra-low demand load, the current return water status of the chiller unit is determined based on the inlet water temperature of the evaporator. If the water source is in a constant temperature return state, the water flow rate of the mixing circuit is adjusted based on the evaporator's outlet water temperature and evaporation pressure according to the first strategy. This includes: detecting the rate of change ΔT1 per minute of the outlet water temperature T1 within a preset time period before the chiller's water flow rate drops to 50% of the rated water flow rate L; determining whether all ΔT1 values ​​are ≤ -k2; if so, controlling the mixing solenoid valve to open and the mixing auxiliary pump to open, increasing the chiller's water flow rate by a%*L / min until T1 < T-k3, at which point the increase stops; if not, controlling the mixing solenoid valve to open and the mixing auxiliary pump to open, adjusting the mixing circuit's water flow rate to b%*rated water flow rate L; where a and b are preset values, and k1, k2, and k3 are preset values; then, according to the... The system adjusts the flow rate of the mixing circuit based on the outlet water temperature T1 and the evaporation pressure P, either increasing or decreasing the flow rate. This includes: determining if the outlet water temperature T1 satisfies the condition T1 ≤ T - k4, where T is a preset required temperature and k4 is a preset value; if yes, increasing the opening of the throttling device to further increase the flow rate of the mixing circuit by c%*L, where c is a preset value; simultaneously, controlling the flow rate of the mixing circuit based on the evaporation pressure to prevent the chiller unit from shutting down due to low pressure protection; if no, stopping the increase in the flow rate of the mixing circuit. The mixing circuit is equipped with the mixing solenoid valve and the mixing auxiliary water pump. Controlling the flow rate of the mixing circuit based on the evaporation pressure to prevent the chiller unit from shutting down due to low pressure protection includes: detecting the evaporation pressure P of the evaporator; and determining if the condition P ≥ the evaporation pressure protection value P. 保 If yes, then return to determine whether the outlet water temperature T1 satisfies: T1≤T-k4; if no, then control the throttling device to remain open until P≥P is satisfied. 保 During this period, the water flow rate in the mixing circuit is stopped; wherein, the throttling device is installed on the pipeline between the condenser and the evaporator; If the water source is not at a constant temperature, the water flow rate of the mixing circuit is adjusted according to the outlet water temperature of the evaporator based on the second strategy. This includes: controlling the opening of the mixing solenoid valve; controlling the opening of the mixing auxiliary water pump; increasing the water flow rate of the chiller unit by increments of a%*L / min until T1 < T-k3, at which point the increase in the chiller unit's water flow rate stops; where a is a preset value, k3 is a preset value, and the mixing circuit is equipped with the mixing solenoid valve and the mixing auxiliary water pump. The mixing water path is a bypass pipe from the inlet of the evaporator to the outlet.

2. The method according to claim 1, characterized in that, The chiller unit is operating at a preset ultra-low demand load, including: If the water flow rate of the chiller unit drops to 50% of the rated water flow rate L, then the chiller unit is determined to be under preset ultra-low demand load.

3. The method according to claim 1, characterized in that, The current return water status of the chiller unit is determined based on the evaporator inlet water temperature, including: The rate of change ΔT0 per minute of the inlet water temperature T0 is measured within a preset time period before the water flow rate of the chiller unit drops to 50% of the rated water flow rate L. Determine whether all ΔT0 ≥ -k1; where k1 is a preset value; If so, then the current return water status of the chiller unit is determined to be constant temperature water source return water status; If not, then the current return water status of the chiller unit is determined to be a non-constant temperature water source return water status.

4. The method according to claim 1, characterized in that, The method further includes: During the process of adjusting the water flow rate of the mixing circuit based on the outlet water temperature and evaporation pressure of the evaporator according to the first strategy, if the actual demand load of the chiller unit increases, the mixing auxiliary water pump will be shut down.

5. The method according to claim 1, characterized in that, The method further includes: In the process of adjusting the water flow rate of the mixing circuit based on the outlet water temperature of the evaporator according to the second strategy, if the actual demand load of the chiller unit increases, the water flow rate of the chiller unit will be reduced by a%*L / min.

6. The method according to claim 1, characterized in that, Before the chiller unit reaches a preset ultra-low demand load, the method further includes: When the chiller unit is under preset low demand load, the water flow rate of the chiller unit is adjusted according to the inlet and outlet water temperatures of the evaporator.

7. The method according to claim 6, characterized in that, The chiller unit is operating at a preset low demand load, including: After the chiller unit starts cooling operation, if the load decreases until it is unloaded to the preset minimum operating load, then the chiller unit is determined to be at the preset low demand load.

8. The method according to claim 6, characterized in that, Adjusting the water flow rate of the chiller unit according to the inlet and outlet water temperatures of the evaporator includes: Determine whether the following condition is met continuously within time t: outlet water temperature T1 ≤ T - k2; where T is the preset required temperature and k2 is the preset value; If so, adjust the water flow rate of the chiller unit according to the inlet water temperature T0 of the evaporator; If not, maintain the current state and do not adjust the water flow rate of the chiller unit.

9. The method according to claim 8, characterized in that, Adjust the water flow rate of the chiller unit according to the evaporator inlet water temperature T0, including: Calculate (T - T1) / (T0 - T1) = m%. Reduce the water flow rate of the chiller unit by m% * rated water flow rate (L); Then return to the execution steps: determine whether the following condition is met continuously within time t: outlet water temperature T1≤T-k2; until the water flow rate of the chiller unit drops to 50% of L, then it is determined that the chiller unit is under the preset ultra-low demand load.

10. The method according to claim 6, characterized in that, The method further includes: When the chiller unit is at a preset low demand load, during the process of adjusting the chiller unit's water flow rate according to the evaporator's inlet and outlet water temperatures, if the actual demand load of the chiller unit increases, the chiller unit's water flow rate is increased to the rated water flow rate L by an increment of c%*L / min, and then the chiller unit loading operation is executed; where c is a preset value.

11. The method according to claim 1, characterized in that, The method further includes: When the chiller unit is under preset high demand load, the water flow rate of the chiller unit is adjusted according to the changes in operating load and the outlet water temperature of the evaporator.

12. The method according to claim 11, characterized in that, The chiller unit is operating at a preset high demand load, including: When the chiller unit is running stably at its rated water flow rate L, the operating load Q of the chiller unit is detected. Determine whether Q≥X%. If so, determine that the chiller unit is under the preset high demand load; where X is the preset value.

13. The method according to claim 11, characterized in that, Adjusting the water flow rate of the chiller unit according to changes in operating load and evaporator outlet water temperature includes: Detect the change in operating load within a preset time period t: ΔQ = Q tmin -Q0; where Q tmin Q0 is the operating load at the end of time t, and Q0 is the initial operating load. Determine whether the following condition is met: ΔQ≥A; where A is the load change limit. If so, the water flow rate of the chiller unit is increased by c%*rated water flow rate L, where c is a preset value; at the same time, the operating load of the chiller unit is checked to see if it is already fully loaded. If the chiller unit has not been loaded to full load, the load is continued; if it is already fully loaded, the water flow rate of the chiller unit is adjusted according to the outlet water temperature. If not, there is no need to adjust the water flow rate of the chiller unit; it can continue to operate stably at the rated water flow rate L.

14. The method according to claim 13, characterized in that, If the unit is fully loaded, adjust the water flow rate of the chiller unit according to the outlet water temperature, including: Determine whether the outlet water temperature T1 satisfies: T1≥T+k2; where T is the preset required temperature and k2 is the preset value; If so, increase the water flow rate of the chiller unit by a%*L / min until T1<T+k2, then stop increasing the water flow rate of the chiller unit. If not, then do not adjust the water flow rate of the chiller unit.

15. A water flow regulating device, characterized in that, The device includes: The judgment module is used to determine the current return water status of the chiller unit based on the inlet water temperature of the evaporator when the chiller unit is under a preset ultra-low demand load. The first processing module is used to adjust the water flow rate of the mixing circuit based on the outlet water temperature and evaporation pressure of the evaporator under constant temperature water source return conditions, according to a first strategy. This adjustment includes: detecting the rate of change ΔT1 per minute of the outlet water temperature T1 within a preset time period before the water flow rate of the chiller unit drops to 50% of the rated water flow rate L; determining whether all ΔT1 values ​​are ≤ -k2; if so, controlling the mixing solenoid valve to open and the mixing auxiliary water pump to open, increasing the chiller unit's water flow rate by a%*L / min until T1 < T-k3, at which point the increase in chiller unit's water flow rate stops; if not, controlling the mixing solenoid valve to open and the mixing auxiliary water pump to open, adjusting the water flow rate of the mixing circuit to b%*rated water flow rate L; where a and b are preset values, and k1, k2, and k3 are preset values; then... The process involves increasing or stopping the water flow rate in the mixing circuit based on the outlet water temperature T1 and the evaporation pressure P. This includes: determining whether the outlet water temperature T1 satisfies the condition T1 ≤ T - k4, where T is a preset required temperature and k4 is a preset value; if yes, increasing the opening of the throttling device to further increase the water flow rate in the mixing circuit by c%*L, where c is a preset value; simultaneously, controlling the water flow rate in the mixing circuit based on the evaporation pressure to prevent the chiller unit from shutting down due to low pressure protection; if no, stopping the increase in the water flow rate in the mixing circuit. The mixing circuit is equipped with the mixing solenoid valve and the mixing auxiliary water pump. Controlling the water flow rate in the mixing circuit based on the evaporation pressure to prevent the chiller unit from shutting down due to low pressure protection includes: detecting the evaporation pressure P of the evaporator; and determining whether the condition P ≥ the evaporation pressure protection value P is satisfied. 保 If yes, then return to determine whether the outlet water temperature T1 satisfies: T1≤T-k4; if no, then control the throttling device to remain open until P≥P is satisfied. 保 During this period, the water flow rate in the mixing circuit is stopped; wherein, the throttling device is installed on the pipeline between the condenser and the evaporator; The second processing module is used to adjust the water flow rate of the mixing circuit based on the outlet water temperature of the evaporator according to a second strategy under the non-constant temperature water source return state. This adjustment includes: controlling the opening of the mixing solenoid valve; controlling the opening of the mixing auxiliary water pump; increasing the water flow rate of the chiller unit by an increment of a%*L / min until T1 < T-k3, at which point the increase in the chiller unit's water flow rate stops; where a is a preset value, k3 is a preset value, and the mixing circuit is equipped with the mixing solenoid valve and the mixing auxiliary water pump. The mixing water path is a bypass pipe from the inlet of the evaporator to the outlet.

16. A water chiller unit, characterized in that, The chiller unit includes a compressor, a condenser, a throttling device, and an evaporator connected in sequence, a mixing channel from the inlet of the evaporator to the outlet, and also includes the water flow regulating device as described in claim 15.

17. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 14.

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