Compressor control method and device for water chiller and water chiller

Abstract

The application relates to the technical field of water chilling unit, and discloses a compressor control method for a water chilling unit, which comprises the following steps: in the case that the water chilling unit is operated in a refrigeration mode, the chilled water inlet temperature and the actual chilled water outlet temperature are acquired, and the evaporation temperature lower limit threshold of each compressor group is acquired; in the case that the chilled water inlet temperature meets the compressor starting condition, the number of the compressors of the target compressor group is determined according to the chilled water inlet temperature, the evaporation temperature lower limit threshold of the target compressor group and the compressor refrigerating capacity of the target compressor group; and the target compressor group is controlled to start operation according to the number of the compressors. The method can obtain the chilled water outlet temperature with a large temperature range. The application further discloses a compressor control device for the water chilling unit and the water chilling unit.

Description

Technical Field

[0001] This application relates to the field of chiller technology, for example to a compressor control method and device for a chiller, and a chiller. Background Technology

[0002] Currently, chillers have a wide influence in the commercial sector. In certain specialized applications, chillers need to provide a wide range of outlet water temperatures to meet the specific temperature requirements of those applications.

[0003] To address the aforementioned technical problems, a control method for a chiller unit is disclosed. The chiller unit includes an evaporator, a condenser, and multiple compressors, forming a closed-loop main circulation circuit, wherein the multiple compressors are connected in parallel. The control method includes: acquiring the outlet water temperature of the chiller unit during operation; calculating the cooling capacity of any compressor currently in operation; determining whether to put the chiller unit into an energy-saving strategy mode based on the outlet water temperature and cooling capacity; if it is determined that the chiller unit should enter the energy-saving strategy mode, determining an adjustment strategy for the number of compressors in operation based on the cooling capacity; and adjusting the number of compressors in operation according to the adjustment strategy.

[0004] In the process of implementing the embodiments of this disclosure, at least the following problems were found in the related art:

[0005] Although the relevant technologies can achieve gradient cooling, the range of cooling capacity corresponding to the unit is not large after different combinations of compressors are turned on due to the parallel connection of multiple compressors. The range of outlet water temperature is also relatively limited, making it difficult to meet the temperature requirements of special application scenarios.

[0006] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0008] This disclosure provides a compressor control method and apparatus for a chiller unit, and a chiller unit, to obtain chilled water outlet temperature with a wide temperature range.

[0009] In some embodiments, the chiller unit includes an evaporator group, a compressor system, and a condenser. The evaporator group includes multiple evaporators connected in series along the chilled water flow direction. The compressor system includes multiple compressor groups, and the condenser is connected to each evaporator through different compressor groups. The control method includes: when the chiller unit is operating in cooling mode, acquiring the chilled water inlet temperature, the actual chilled water outlet temperature, and the lower limit threshold of the evaporation temperature of each compressor group; when the chilled water inlet temperature meets the compressor start-up conditions, determining the number of compressors operating in the target compressor group based on the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor group, and the compressor cooling capacity of the target compressor group, wherein the target compressor group is determined by the compressor start-up conditions; and controlling the target compressor group to start operation according to the number of compressors operating.

[0010] In some embodiments, the evaporator group includes a first evaporator and a second evaporator, ..., an Nth evaporator connected in series along the chilled water flow direction. The mth compressor group is connected to the mth evaporator. The chilled water inlet temperature is determined to meet the compressor start-up conditions and the target compressor is determined as follows: if the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the first evaporator temperature and the first temperature deviation, the chilled water inlet temperature is determined to meet the compressor start-up conditions, and the first compressor group is determined to be the target compressor group; if the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the mth evaporator temperature and the first temperature deviation, and less than the sum of the lower limit threshold of the (m-1)th evaporator temperature and the first temperature deviation, the chilled water inlet temperature is determined to meet the compressor start-up conditions, and the mth compressor group is determined to be the target compressor group; wherein, the lower limit threshold of the mth evaporator temperature represents the lower limit value of the evaporator temperature of the mth compressor group, and m is negatively correlated with the lower limit threshold of the mth evaporator temperature, m = 2, ..., N.

[0011] In some embodiments, each compressor unit includes multiple compressors of the same model connected in parallel. The compressor cooling capacity represents the cooling capacity of a single compressor in the compressor unit. The number of compressors operating in the target compressor unit is determined based on the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the compressor cooling capacity of the target compressor unit. This includes: based on... Determine the number of compressors operating in the target compressor unit; where, if the target compressor unit is the first compressor, ΔT = T. i -T1, and Q j =Q1; When the target compressor unit is the z-th compressor, ΔT = T z-1 -T z And Q j =Q z When the target compressor unit is the Nth compressor, ΔT = T N-1 -T, and Q j =QN ;T z T1 and T2 represent the lower limit threshold of the evaporation temperature of the z-th compressor unit and the target outlet temperature of the chilled water, respectively. T1 represents the lower limit threshold of the evaporation temperature of the first compressor unit. i Q represents the chilled water inlet temperature. n Let α represent the cooling capacity of a single compressor in the nth compressor group, α represent the proportionality coefficient, and z be 2, ..., N-1.

[0012] In some embodiments, the method further includes: after controlling the target compressor unit to start operation according to the number of compressors in operation, obtaining the target chilled water outlet temperature; and performing unit loading / unloading operations on the target compressor unit when the actual chilled water outlet temperature meets the compressor loading / unloading conditions.

[0013] In some embodiments, when the actual chilled water outlet temperature meets the compressor loading / unloading conditions, the target compressor unit is subjected to unit loading / unloading operations, including: if the target compressor unit is the s-th compressor unit, and the actual chilled water outlet temperature is less than or equal to the difference between the s-th evaporation lower limit threshold and the second temperature deviation, then the s-th compressor unit is subjected to unit unloading operations; if the target compressor is the s-th compressor unit, and the actual chilled water outlet temperature is greater than the difference between the s-th evaporation lower limit threshold and the second temperature deviation but less than the s-th evaporation lower limit threshold and the second temperature deviation... If the sum of the values ​​is 1, 2, ..., N-1, then the unit loading operation is performed on the s-th compressor unit; if the actual chilled water outlet temperature is less than or equal to the difference between the target chilled water outlet temperature and the second temperature deviation, then the unit unloading operation is performed on the N-th compressor unit; if the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation and less than the sum of the target chilled water outlet temperature and the second temperature deviation, then the unit loading operation is performed on the N-th compressor unit; where s is 1, 2, ..., N-1.

[0014] In some embodiments, the method further includes: if the target compressor is the s-th compressor group, and the actual chilled water outlet temperature is greater than the sum of the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, then the s-th compressor group is kept running continuously; if the target compressor is the N-th compressor group, and the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation and less than the sum of the target chilled water outlet temperature and the second temperature deviation, then the N-th compressor group is kept running continuously.

[0015] In some embodiments, performing load reduction / unload operations on the target compressor unit includes: obtaining the running time of each compressor in the target compressor unit; determining the compressor with the longest running time as the first target compressor and the compressor with the shortest running time as the second target compressor; performing a load reduction operation on the first target compressor, or performing a load loading operation on the second target compressor.

[0016] In some embodiments, the control device includes a processor and a memory storing program instructions, the processor being configured to execute, when running the program instructions, the compressor control method for a chiller unit as described above.

[0017] In some embodiments, the chiller unit includes: a unit body, including: an evaporator assembly and a condenser, a compressor system, the evaporator assembly including a plurality of evaporators connected in series along the chilled water flow direction, the compressor system including a plurality of compressor units and the condenser being connected to each evaporator through different compressor units; and a compressor control device for the chiller unit as described above, installed on the unit body.

[0018] In some embodiments, each compressor unit of the chiller unit includes multiple compressors of the same model connected in parallel.

[0019] The compressor control method and apparatus for chiller units, and the chiller units provided in this disclosure can achieve the following technical effects:

[0020] This embodiment selects the target compressor unit based on the chilled water inlet temperature and accurately determines the number of compressors operating in the target compressor unit by combining the target compressor unit's evaporator temperature lower limit threshold and compressor cooling capacity. This allows for the identification of the target compressor unit from the compressor system that achieves the target chilled water outlet temperature and is compatible with the specific chilled water inlet temperature. Based on this, this embodiment can obtain a chilled water outlet temperature with a wide temperature range even when using a shared condenser and refrigeration mode.

[0021] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0022] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0023] Figure 1 This is a schematic diagram of the system structure of the chiller unit provided in the embodiments of this disclosure;

[0024] Figure 2This is a schematic diagram of a compressor control method for a chiller unit provided in an embodiment of this disclosure;

[0025] Figure 3 This is a schematic diagram of another compressor control method for a chiller unit provided in an embodiment of this disclosure;

[0026] Figure 4 This is a schematic diagram of another compressor control method for a chiller unit provided in an embodiment of this disclosure;

[0027] Figure 5 This is a schematic diagram of another compressor control method for a chiller unit provided in an embodiment of this disclosure;

[0028] Figure 6 This is an application illustration of an embodiment of the present disclosure;

[0029] Figure 7 This is a schematic diagram of a compressor control device for a chiller unit provided in an embodiment of this disclosure.

[0030] Figure label:

[0031] 10: Chiller unit; 101: Evaporator unit; 103: Condenser; 1021: Compressor unit;

[0032] 1011: First evaporator; 1012: Second evaporator; 1013: Nth evaporator. Detailed Implementation

[0033] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0034] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0035] Unless otherwise stated, the term "multiple" means two or more.

[0036] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0037] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0038] The term "correspondence" can refer to an association or binding relationship. The correspondence between A and B means that there is an association or binding relationship between A and B.

[0039] Combination Figure 1 As shown, this embodiment of the present disclosure provides a chiller unit 10. The chiller unit 10 includes an evaporator group 101, a compressor system, and a condenser 103. The evaporator group 101 includes multiple evaporators connected in series along the chilled water flow direction. The compressor system includes multiple compressor groups 1021, and the condenser 103 is connected to each evaporator through different compressor groups 1021.

[0040] As an example, evaporator group 101 includes a first evaporator 1011 and a second evaporator 1012, ... an Nth evaporator 1013 connected in series along the chilled water flow direction, and an mth compressor unit is connected to the mth evaporator. That is, N represents the total number of evaporators in evaporator group 101, and N is an integer greater than or equal to 3.

[0041] Optionally, each compressor unit includes multiple compressors of the same model connected in parallel.

[0042] Based on the above-mentioned system structure of the chiller unit, combined with Figure 2 As shown, this disclosure provides a compressor control method for a chiller unit, including:

[0043] S01, when the chiller unit is operating in cooling mode, the chiller unit obtains the chilled water inlet temperature and the actual chilled water outlet temperature, as well as the lower limit threshold of the evaporation temperature of each compressor unit.

[0044] S02, when the chilled water inlet temperature meets the compressor start-up conditions, the chiller unit determines the number of compressors operating in the target compressor unit based on the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the compressor cooling capacity of the target compressor unit. The target compressor unit is determined by the compressor start-up conditions.

[0045] S03, the chiller unit controls the start-up and operation of the target compressor unit according to the number of compressors in operation.

[0046] The compressor control method for chiller units provided in this disclosure, when the chiller unit is operating in cooling mode, first obtains the chilled water inlet temperature, the actual chilled water outlet temperature, and the lower limit threshold of the evaporator temperature for each compressor unit. If the chilled water inlet temperature meets the compressor start-up conditions, the number of operating compressors for the target compressor unit is calculated based on the chilled water inlet temperature, the lower limit threshold of the evaporator temperature of the target compressor unit, and the compressor cooling capacity of the target compressor unit. The target compressor unit is then started and operated according to this operating data. This disclosure selects the target compressor unit based on the chilled water inlet temperature and accurately determines the number of operating compressors for the target compressor unit by combining its evaporator temperature lower limit threshold and compressor cooling capacity. This allows for the identification of target compressor units that achieve the target chilled water outlet temperature and are compatible with the specific chilled water inlet temperature value from the compressor system. Based on this, this disclosure can obtain chilled water outlet temperatures with a large temperature range when operating in cooling mode and with a shared condenser.

[0047] Furthermore, the embodiments disclosed herein employ a shared condenser structure, which, compared to the structure of a single condenser in related technologies, results in a simpler system structure and a better effect on regulating the chilled water outlet temperature.

[0048] Optionally, the chiller unit determines whether the chilled water inlet temperature meets the compressor start-up conditions and identifies the target compressor in the following manner:

[0049] When the chilled water inlet temperature is greater than or equal to the sum of the first evaporation temperature lower limit threshold and the first temperature deviation, the chiller unit determines that the chilled water inlet meets the compressor start-up conditions and identifies the first compressor unit as the target compressor unit.

[0050] If the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the m-th evaporation temperature and the first temperature deviation, and less than the sum of the lower limit threshold of the m-1-th evaporation temperature and the first temperature deviation, it is determined that the chilled water inlet meets the compressor start-up conditions, and the m-th compressor unit is determined as the target compressor unit.

[0051] Wherein, the lower limit threshold of the m-th evaporator temperature represents the lower limit value of the evaporator temperature of the m-th compressor unit, and m is negatively correlated with the lower limit threshold of the m-th evaporator temperature, m = 2, ..., N.

[0052] Thus, since m is negatively correlated with the lower limit threshold of the temperature of the m-th evaporator, and the first evaporator, the second evaporator, ..., the N-th evaporator are connected in series in sequence along the flow direction of the chilled water, the lower limit threshold of the evaporator temperature of the evaporator closer to the chilled water inlet of the evaporator group is higher, while the lower limit threshold of the evaporator temperature of the evaporator farther from the chilled water inlet of the evaporator group is lower. Based on this, if the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the first evaporation temperature and the first temperature deviation, it indicates that the compressor system needs to be started for refrigeration, and the first compressor unit with a relatively high lower limit threshold of the evaporator temperature is preferentially selected for refrigeration. If the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the m-th evaporation temperature and the first temperature deviation and less than the sum of the lower limit threshold of the (m - 1)-th evaporation temperature and the first temperature deviation, it indicates that the compressor system needs to be started for refrigeration. At the same time, since the lower limit threshold of the evaporator temperature of the first compressor unit is relatively high, it is difficult to reach the target chilled water outlet temperature by using the first compressor unit as the target compressor unit. Therefore, other compressors with a lower limit threshold of the evaporator temperature slightly lower than that of the first compressor are selected as the target compressors to achieve refrigeration. It can be seen from this that the embodiments of the present disclosure can determine the target compressor unit adapted to the chilled water inlet temperature from the compressor system based on the magnitude of the chilled water inlet temperature, so as to obtain a chilled water outlet temperature with a larger temperature range under the condition of sharing the refrigeration mode and the condenser.

[0053] As an example, N is 3, that is, the first evaporator, the second evaporator, and the third evaporator are connected in series in sequence along the flow direction of the chilled water. The condenser is connected to the first evaporator through the first compressor unit, the condenser is also connected to the second evaporator through the second compressor unit, and the condenser is also connected to the third evaporator through the third compressor unit.

[0054] The chiller determines the target compressor in the following manner:

[0055] When T i ≥ T1 + t0, the first compressor is determined as the target compressor unit.

[0056] When T2 + t0 ≤ T i < T1 + t0, the second compressor is determined as the target compressor unit.

[0057] When T3 + t0 ≤ T i < T2 + t0, the third compressor is determined as the target compressor unit.

[0058] Among them, T i represents the chilled water inlet temperature, T1 > T2 > T3, and T1, T2, and T3 respectively represent the lower limit threshold of the first evaporator temperature, the lower limit threshold of the second evaporator temperature, and the lower limit threshold of the third evaporator temperature. t0 represents the first temperature deviation.

[0059] It should be noted that the first temperature deviation is greater than zero, and the specific value of the first temperature deviation can be set according to the actual annual cooling scenario of the chiller unit. This disclosed embodiment does not impose specific limitations on this.

[0060] Optionally, the compressor cooling capacity refers to the cooling capacity of a single compressor in the compressor unit. The chiller unit determines the number of compressors operating in the target compressor unit based on the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the compressor cooling capacity of the target compressor unit, including:

[0061] Chiller unit according to Determine the number of compressors operating in the target compressor unit.

[0062] In the case where the target compressor unit is the first compressor, ΔT = T i -T1, and Q j =Q1.

[0063] When the target compressor unit is the z-th compressor, ΔT = T z-1 -T z And Q j =Q z .

[0064] When the target compressor unit is the Nth compressor, ΔT = T N-1 -T, and Q j =Q N .

[0065] T z T1 and T2 represent the lower limit threshold of the evaporation temperature of the z-th compressor unit and the target outlet temperature of the chilled water, respectively. T1 represents the lower limit threshold of the evaporation temperature of the first compressor unit. i Q represents the chilled water inlet temperature. n This represents the cooling capacity of a single compressor in the nth compressor unit, α represents the proportionality coefficient, and z is 2, ..., N-1. α is determined based on the compressor configuration of the chiller unit's compressor group.

[0066] Thus, when each compressor unit is equipped with multiple compressors of the same model connected in parallel, the greater the difference between the chilled water inlet temperature and the lower limit threshold of the evaporator temperature of a certain first compressor unit, the greater the number of compressors required to operate in the target compressor unit. Meanwhile, T z-1 and T z The larger the difference, the greater the number of compressors required to operate for the target compressor. Furthermore, the lower the cooling capacity of a single compressor, the greater the number of compressors required to operate for the target compressor. That is, the number of compressors operating is approximately equal to T. i The difference between T1 and T2 is directly proportional, and the number of compressors operating is roughly the same as T2. z-1 and T zThe difference is directly proportional to the number of compressors operating, and the number of compressors operating is inversely proportional to the cooling capacity of a single compressor in the compressor unit. Considering the above factors, after determining the target compressor unit in the chiller unit of this disclosure embodiment, the number of compressors operating in the compressor unit is calculated based on the chilled water inlet temperature, the lower limit threshold of the evaporator temperature of the target compressor unit, and the cooling capacity of a single compressor in the target compressor unit. This accurately obtains the number of compressors operating in the target compressor unit that achieves the target chilled water outlet temperature and is compatible with the chilled water inlet temperature, thereby obtaining a chilled water outlet temperature with a large temperature range under the condition of shared cooling mode and condenser.

[0067] Optionally, the chiller unit is based on Determine the number of compressors operating in the target compressor unit, including: chiller units based on... Determine the number of compressors operating in the target compressor unit. Here, [·] is the rounding symbol, used to round the calculation result to the nearest integer.

[0068] Based on the above-mentioned system structure of the chiller unit, combined with Figure 3 As shown in the embodiments of this disclosure, a compressor control method for a chiller unit is also provided, including:

[0069] S11, when the chiller unit is operating in cooling mode, the chiller unit obtains the chilled water inlet temperature and the actual chilled water outlet temperature, as well as the lower limit threshold of the evaporation temperature of each compressor unit.

[0070] S12, when the chilled water inlet temperature meets the compressor start-up conditions, the chiller unit determines the number of compressors operating in the target compressor unit based on the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the compressor cooling capacity of the target compressor unit. The target compressor unit is determined by the compressor start-up conditions.

[0071] S13, the chiller unit controls the start-up and operation of the target compressor unit according to the number of compressors in operation.

[0072] S14: After controlling the target compressor unit to start operation according to the number of compressors in operation, and if the actual chilled water outlet temperature meets the compressor loading / unloading conditions, the chiller unit performs unit loading / unloading operations on the target compressor unit.

[0073] The compressor control method for chiller units provided in this disclosure selects a target compressor unit based on the chilled water inlet temperature and accurately determines the number of compressors operating in the target compressor unit by combining the target compressor unit's evaporator temperature lower limit threshold and compressor cooling capacity. This allows for the identification of a target compressor unit that matches the specific chilled water inlet temperature from the compressor system. However, after controlling the target compressors to start operation according to the specified number of compressors, there may still be situations where the number of operating compressors is too high or too low. To avoid an unreasonable number of operating compressors, this disclosure further determines whether the chilled water outlet temperature meets the load adjustment conditions. If it does, it performs unit load adjustment operations on the target compressors to obtain a chilled water outlet temperature with a wide temperature range while ensuring that the chilled water outlet temperature accurately reaches the target chilled water outlet temperature under refrigeration mode and condenser sharing conditions. Simultaneously, this reduces the operating energy consumption of the chiller unit.

[0074] Combination Figure 4 As shown, when the actual chilled water outlet temperature meets the compressor loading / unloading conditions, the chiller unit performs unit loading / unloading operations on the target compressor unit, including:

[0075] S21, if the target compressor unit is the s-th compressor unit, and the actual chilled water outlet temperature is less than or equal to the difference between the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, then the chiller unit will perform a unit load reduction operation on the s-th compressor unit.

[0076] S22, if the target compressor is the s-th compressor unit, and the actual chilled water outlet temperature is greater than the difference between the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, but less than the sum of the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, then the chiller unit performs a unit loading operation on the s-th compressor unit.

[0077] S23, if the target compressor is the Nth compressor unit, and the actual chilled water outlet temperature is less than or equal to the difference between the target chilled water outlet temperature and the second temperature deviation, then the chiller unit will perform a unit load reduction operation on the Nth compressor unit.

[0078] S24, if the target compressor is the Nth compressor group, and the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation, but less than the sum of the target chilled water outlet temperature and the second temperature deviation, then the chiller unit performs a unit loading operation on the Nth compressor group.

[0079] Where s is 1, 2, ..., N-1.

[0080] Thus, when the target compressor unit is compressor unit s, if the actual chilled water outlet temperature is less than or equal to the difference between the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, it indicates that the actual chilled water outlet temperature is relatively low, and the number of compressors operating in compressor unit s is too high. In this case, a unit load reduction operation is performed. Conversely, if the actual chilled water outlet temperature is greater than the difference between the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, but less than the sum of the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, it indicates that the actual chilled water outlet temperature is relatively high, and the number of compressors operating in compressor unit s is too low. In this case, a unit load operation is performed. When the target compressor unit is compressor unit N, if the actual chilled water outlet temperature is less than or equal to the difference between the target chilled water outlet temperature and the second temperature deviation, it indicates that the actual chilled water outlet temperature is relatively low, and the number of compressors operating in compressor unit N is too high. In this case, a unit load reduction operation is performed. If the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation, but less than the sum of the target chilled water outlet temperature and the second temperature deviation, it indicates that the actual chilled water outlet temperature is relatively high and the number of compressors operating in the Nth compressor group is low. In this case, a unit loading operation is performed on it.

[0081] It should be noted that the second temperature deviation is greater than zero, and the specific value of the second temperature deviation can be set according to the actual annual cooling scenario of the chiller unit. This disclosed embodiment does not impose specific limitations on this.

[0082] Optionally, when the actual chilled water outlet temperature meets the compressor loading / unloading conditions, the chiller unit performs unit loading / unloading operations on the target compressor unit, which also includes:

[0083] If the target compressor is compressor unit s, and the actual chilled water outlet temperature is greater than the sum of the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, then the chiller unit will continue to operate compressor unit s.

[0084] If the target compressor is compressor group N, and the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation, but less than the sum of the target chilled water outlet temperature and the second temperature deviation, then the chiller unit will continue to operate compressor group N.

[0085] Thus, when the target compressor is compressor group s, if the actual chilled water outlet temperature is greater than the sum of the lower limit threshold of the s-th evaporator and the second temperature deviation, it indicates that the actual chilled water temperature is within a suitable temperature range, and no load adjustment operation is required. When the target compressor is compressor group N, if the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation, but less than the sum of the target chilled water outlet temperature and the second temperature deviation, it indicates that the actual chilled water temperature is within a suitable temperature range, and no load adjustment operation is required.

[0086] Optionally, combined Figure 5 As shown, the chiller unit performs load increase / decrease operations on the target compressor unit, including:

[0087] S31, the chiller unit obtains the operating time of each compressor in the target compressor unit.

[0088] S32, the chiller unit determines the compressor with the longest running time as the first target compressor and the compressor with the shortest running time as the second target compressor.

[0089] S33, the chiller unit performs a load reduction operation on the first target compressor, or a load operation on the second target compressor.

[0090] Thus, in this embodiment of the disclosure, the target compressor is identified based on the runtime of each compressor in the target compressor unit, specifically the one with the longest unloading runtime and the shortest loading runtime. Through the above-described load reduction and unloading methods, a stable and reliable transition between load reduction and unloading can be achieved.

[0091] In practical applications, such as Figure 1 and Figure 6 As shown, N is 3. The evaporator group includes a first evaporator, a second evaporator, and a third evaporator connected in series along the chilled water flow direction. The condenser is connected to the first evaporator through a first compressor unit, the condenser is also connected to the second evaporator through a second compressor unit, and the condenser is also connected to the third evaporator through a third compressor unit.

[0092] The compressor control method for chiller units specifically follows these steps:

[0093] S41, When the chiller unit is operating in cooling mode, the chiller unit obtains the chilled water inlet temperature T. i and the actual chilled water outlet temperature T o The lower limit threshold of the evaporation temperature for each compressor unit.

[0094] S42, when T i When ≥T1+t0, the chiller unit determines the first compressor as the target compressor unit, and according to... Determine the number of operating compressors of the first compressor, and execute S45. Among them, T z , T respectively represent the lower limit threshold of the evaporation temperature of the z-th compressor unit and the target chilled water outlet temperature, T1 represents the lower limit threshold of the evaporation temperature of the first compressor unit, T i represents the chilled water inlet temperature, Q n represents the refrigerating capacity of a single compressor of the n-th compressor unit, α represents the proportionality coefficient, and z is 2,..., N - 1.

[0095] S43, when T2 + t0 ≤ T i < T1 + t0, the chiller determines the second compressor as the target compressor unit, and according to determine the number of operating compressors of the second compressor, and execute S49.

[0096] S44, when T3 + t0 ≤ T i < T2 + t0, the chiller determines the third compressor as the target compressor unit, and according to determine the number of operating compressors of the third compressor, and execute S53.

[0097] S45, the chiller judges whether T o ≤ T1 - t1 holds. If it holds, execute S46; otherwise, execute S47.

[0098] S46, the chiller unloads the compressor with the longest running time in the first compressor unit.

[0099] S47, the chiller judges whether T1 - t1 < T o ≤ T1 + t1 holds. If it holds, execute S48; otherwise, do not perform loading or unloading operations on the first compressor unit.

[0100] S48, the chiller loads the compressor with the shortest running time in the first compressor unit.

[0101] S49 , the chiller judges whether T o ≤ T2 - t1 holds. If it holds, execute S50; otherwise, execute S51. Among them, t1 represents the second temperature deviation.

[0102] S50, the chiller unloads the compressor with the longest running time in the second compressor unit.

[0103] S51, the chiller judges whether T2 - t1 < T o ≤ T2 + t1 holds. If it holds, execute S52; otherwise, do not perform loading or unloading operations on the second compressor unit.

[0104] S52, the chiller unit loads the compressor with the shortest operating time in the second compressor unit.

[0105] S53 Chiller unit determines T o Check if ≤T-t1 is true. If true, execute S54; otherwise, execute S55.

[0106] S54, the chiller unit performs a load reduction operation on the compressor with the longest operating time in the third compressor unit.

[0107] S55, Chiller unit T-t1 judgment <T o If ≤T+t1 is true, execute S56; otherwise, do not perform load increase / decrease operations on the third compressor unit.

[0108] S56, the chiller unit loads the compressor with the shortest operating time in the third compressor unit.

[0109] Combination Figure 7 As shown, this disclosure provides a compressor control device 70 for a chiller unit, including a processor 700 and a memory 701. Optionally, the device 70 may further include a communication interface 702 and a bus 703. The processor 700, communication interface 702, and memory 701 can communicate with each other via the bus 703. The communication interface 702 can be used for information transmission. The processor 700 can call logical instructions in the memory 701 to execute the compressor control method for a chiller unit described in the above embodiment.

[0110] Furthermore, the logic instructions in the aforementioned memory 701 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0111] The memory 701, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 700 executes functional applications and data processing by running the program instructions / modules stored in the memory 701, thereby implementing the compressor control method for the chiller unit in the above embodiments.

[0112] The memory 701 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 701 may include high-speed random access memory and may also include non-volatile memory.

[0113] Combination Figure 1 As shown, this disclosure provides a chiller unit 10, including: a product body, and the aforementioned compressor control device 70 for the chiller unit. The compressor control device 70 for the chiller unit is installed on the unit body. The installation relationship described herein is not limited to placement inside the unit body, but also includes installation connections with other components of the chiller unit 10, including but not limited to physical connections, electrical connections, or signal transmission connections. Those skilled in the art will understand that the compressor control device 70 for the chiller unit can be adapted to feasible unit bodies to achieve other feasible embodiments.

[0114] This disclosure provides a computer-readable storage medium storing computer-executable instructions configured to execute the above-described compressor control method for a chiller unit.

[0115] The technical solutions of this disclosure can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes one or more 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 method described in this disclosure. The aforementioned storage medium can be a non-transitory storage medium, such as a USB flash drive, external hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk, etc., and other media capable of storing program code.

[0116] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0117] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0118] The methods and products (including but not limited to devices and equipment) disclosed in the embodiments herein can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed units may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms. 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 units may be selected to implement this embodiment according to actual needs. Furthermore, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0119] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A compressor control method for a chiller unit, characterized in that, The chiller unit includes an evaporator assembly, a compressor system, and a condenser. The evaporator assembly includes multiple evaporators connected in series along the chilled water flow direction. The compressor system includes multiple compressor units, and the condenser is connected to each evaporator through different compressor units. The evaporator assembly includes a first evaporator, a second evaporator, ..., an Nth evaporator connected in series along the chilled water flow direction. The mth compressor unit is connected to the mth evaporator. The control method includes: When the chiller unit is operating in cooling mode, obtain the chilled water inlet temperature, the actual chilled water outlet temperature, and the lower limit threshold of the evaporation temperature for each compressor unit. When the chilled water inlet temperature meets the compressor start-up conditions, the number of compressors operating in the target compressor unit is determined based on the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the compressor cooling capacity of the target compressor unit. The target compressor unit is determined by the compressor start-up conditions. Control the startup and operation of the target compressor unit according to the number of compressors in operation; Determine whether the chilled water inlet temperature meets the compressor start-up conditions and identify the target compressor unit using the following methods: If the chilled water inlet temperature is greater than or equal to the sum of the first evaporation temperature lower limit threshold and the first temperature deviation, it is determined that the chilled water inlet meets the compressor start-up conditions, and the first compressor unit is determined as the target compressor unit. If the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the m-th evaporation temperature and the first temperature deviation, and less than the sum of the lower limit threshold of the (m-1)-th evaporation temperature and the first temperature deviation, it is determined that the chilled water inlet meets the compressor start-up conditions, and the m-th compressor unit is determined as the target compressor unit. Wherein, the lower limit threshold of the m-th evaporator temperature represents the lower limit value of the evaporator temperature of the m-th compressor unit, and m is negatively correlated with the lower limit threshold of the m-th evaporator temperature, m=2,...,N.

2. The control method according to claim 1, characterized in that, Each compressor unit includes multiple compressors of the same model connected in parallel. The compressor cooling capacity represents the cooling capacity of a single compressor in the compressor unit. Based on the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the compressor cooling capacity of the target compressor unit, the number of compressors operating in the target compressor unit is determined, including: according to Determine the number of compressors operating in the target compressor unit; In the case where the target compressor unit is the first compressor, ; When the target compressor unit is the z-th compressor. ; When the target compressor unit is the Nth compressor. ,and ; This represents the lower limit threshold of the evaporation temperature of the z-th compressor unit. Indicates the target outlet temperature of the chilled water. This indicates the lower limit threshold of the evaporator temperature of the first compressor unit. Indicates the chilled water inlet temperature. This represents the cooling capacity of a single compressor in the nth compressor group. This represents the proportionality constant, where z is 2,...,N-1.

3. The control method according to claim 1, characterized in that, Also includes: After controlling the target compressor unit to start operation according to the number of compressors in operation, the target outlet temperature of chilled water is obtained; When the actual chilled water outlet temperature meets the compressor loading / unloading conditions, load loading / unloading operations are performed on the target compressor unit.

4. The control method according to claim 3, characterized in that, When the actual chilled water outlet temperature meets the compressor loading / unloading conditions, perform load loading / unloading operations on the target compressor unit, including: If the target compressor unit is the s-th compressor unit, and the actual chilled water outlet temperature is less than or equal to the difference between the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, then the s-th compressor unit will be subjected to a load reduction operation. If the target compressor unit is the s-th compressor unit, and the actual chilled water outlet temperature is greater than the difference between the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, but less than the sum of the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, then the s-th compressor unit will be loaded. If the target compressor unit is the Nth compressor unit, and the actual chilled water outlet temperature is less than or equal to the difference between the target chilled water outlet temperature and the second temperature deviation, then the Nth compressor unit will be subjected to a load reduction operation. If the target compressor unit is the Nth compressor unit, and the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation but less than the sum of the target chilled water outlet temperature and the second temperature deviation, then the Nth compressor unit will be loaded. Where s is 1, 2, ..., N-1.

5. The control method according to claim 4, characterized in that, Also includes: If the target compressor unit is the s-th compressor unit, and the actual chilled water outlet temperature is greater than the sum of the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, then the s-th compressor unit will continue to operate. If the target compressor unit is the Nth compressor unit, and the actual chilled water outlet temperature is greater than the difference between the target chilled water outlet temperature and the second temperature deviation, but less than the sum of the target chilled water outlet temperature and the second temperature deviation, then the Nth compressor unit will continue to operate.

6. The control method according to claim 3, characterized in that, Perform load increase / decrease operations on the target compressor unit, including: Obtain the runtime of each compressor in the target compressor group; The compressor with the longest runtime is designated as the first target compressor, and the compressor with the shortest runtime is designated as the second target compressor. Perform a load reduction operation on the first target compressor, or perform a load increase operation on the second target compressor.

7. A compressor control device for a chiller unit, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to execute, when running the program instructions, the compressor control method for a chiller unit as described in any one of claims 1 to 6.

8. A water chiller unit, characterized in that, include: The unit body includes: an evaporator assembly and a condenser, a compressor system, wherein the evaporator assembly includes multiple evaporators connected in series along the chilled water flow direction, and the compressor system includes multiple compressor units, with the condenser connected to each evaporator via different compressor units; and The compressor control device for a chiller unit as described in claim 7 is installed on the unit body.

9. The chiller unit according to claim 8, characterized in that, Each compressor unit consists of multiple compressors of the same model connected in parallel.

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