Compressor control method and device for water chilling unit and water chilling unit

Abstract

The invention relates to the technical field of water chilling units, and discloses a compressor control method for a water chilling unit, which comprises the following steps: acquiring chilled water inlet temperature, actual chilled water outlet temperature and an evaporation temperature lower limit threshold value of each compressor unit under the condition that the water chilling unit operates in a refrigeration mode; under the condition that the chilled water inlet temperature meets the compressor starting condition, according to the chilled water inlet temperature, the evaporation temperature lower limit threshold value of the target compressor unit and the compressor refrigerating capacity of the target compressor unit, the compressor operation number of the target compressor unit is determined; and controlling the target compressor unit to start and operate according to the compressor operation quantity. According to the method, the chilled water outlet temperature with a large temperature range can be obtained. The invention 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 technical field of chillers, for example, to a compressor control method and device for a chiller, and a chiller. Background Art

[0002] Currently, chillers have a wide influence in the commercial field. In some special application scenarios, chillers need to provide chilled water outlet temperatures within a large temperature range to meet the temperature requirements in special application scenarios.

[0003] To solve the above technical problems, related technologies disclose a control method for a chiller. The chiller includes an evaporator, a condenser, and multiple compressors. The evaporator, the condenser, and the multiple compressors form a closed-loop main circulation circuit, where the multiple compressors are connected in parallel; the control method includes: during the operation of the chiller, obtaining the chilled water outlet temperature of the chiller; calculating the refrigerating capacity of any one of the compressors in the operating state; judging whether to make the chiller enter an energy-saving strategy mode according to the chilled water outlet temperature and the refrigerating capacity; in the case of determining that the chiller enters the energy-saving strategy mode, determining an adjustment strategy for the number of operating compressors according to the refrigerating capacity; and adjusting the number of operating compressors according to the adjustment strategy.

[0004] In the process of implementing the embodiments of the present disclosure, it is found that there are at least the following problems in the related technologies:

[0005] Although the related technologies can achieve gradient cooling, since multiple compressors are connected in parallel, after different combinations of compressors are turned on, the range of the refrigerating capacity interval corresponding to the unit is not large, and the range of the chilled water outlet temperature interval corresponding to the chilled water outlet temperature is relatively limited, making it difficult to meet the temperature requirements in special application scenarios.

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

[0007] To provide a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary is not a comprehensive review, nor is it intended to identify key / important constituent elements or delineate the scope of protection of these embodiments. Instead, it serves as a preamble to the detailed description that follows.

[0008] Embodiments of the present disclosure provide a compressor control method and device for a chiller, and a chiller, to obtain a chilled water outlet temperature with a large temperature range.

[0009] In some embodiments, the chiller includes an evaporator group, a compressor system, and a condenser. The evaporator group includes a plurality of evaporators connected in series along the flow direction of the chilled water. The compressor system includes a plurality of compressor units, and the condenser is connected to each evaporator through different compressor units respectively. The control method includes: when the chiller operates in the refrigeration mode, obtaining the chilled water inlet temperature, the actual chilled water outlet temperature, and the lower limit threshold of the evaporation temperature of each compressor unit; when the chilled water inlet temperature meets the compressor startup condition, determining the number of compressors in operation of the target compressor unit according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigerating capacity of the compressor of the target compressor unit, where the target compressor unit is determined by the compressor startup condition; controlling the startup and operation of the target compressor unit according to the number of compressors in operation.

[0010] In some embodiments, the evaporator group includes a first evaporator, a second evaporator,..., an Nth evaporator connected in series in sequence along the flow direction of the chilled water. The mth compressor unit is respectively connected to the mth evaporator. The method for determining whether the chilled water inlet temperature meets the compressor startup condition and determining the target compressor is as follows: when 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 is determined that the chilled water inlet meets the compressor startup condition, and the first compressor unit is determined as the target compressor unit; when the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the mth 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 startup condition, and the mth compressor unit is determined as the target compressor unit; where the lower limit threshold of the mth evaporator temperature represents the lower limit value of the evaporation temperature of the mth compressor unit, 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 a plurality of compressors of the same model connected in parallel. The refrigerating capacity of the compressor represents the refrigerating capacity of a single compressor of the compressor unit. Determining the number of compressors in operation of the target compressor unit according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigerating capacity of the compressor of the target compressor unit includes: According to Determine the number of compressors in operation of the target compressor unit; where, when the target compressor unit is the first compressor, ΔT = T i - T1, and Q j = Q1; when the target compressor unit is the zth 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 、T respectively represent the lower limit threshold of the evaporation temperature of the z-th compressor unit and the target outlet water temperature of the chilled water. T1 represents the lower limit threshold of the evaporation temperature of the first compressor unit, and T i represents the inlet water temperature of the chilled water, and 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.

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

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

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

[0015] In some embodiments, performing a unit loading and unloading operation on a target compressor unit includes: obtaining the operation duration of each compressor in the target compressor unit; determining the compressor with the longest operation duration as the first target compressor and the compressor with the shortest operation duration as the second target compressor; performing a unit unloading operation on the first target compressor, or performing a unit loading operation on the second target compressor.

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

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

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

[0019] The compressor control method, device, and chiller for a chiller provided by the embodiments of the present disclosure can achieve the following technical effects:

[0020] Based on the chilled water inlet temperature, the embodiments of the present disclosure select a target compressor unit and accurately determine the number of compressors in the target compressor unit to operate by comprehensively considering its lower limit threshold of the evaporator temperature of the target compressor unit and the refrigerating capacity of the compressor, so as to determine a target compressor unit that can reach the target chilled water outlet temperature and is adapted to the specific chilled water inlet temperature value from the compressor system. Based on this, the embodiments of the present disclosure can obtain a chilled water outlet temperature with a larger temperature range in the refrigeration mode and when the condenser is shared.

[0021] The above general description and the following description are only exemplary and explanatory, and are not used to limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily illustrated by corresponding drawings, and these exemplary illustrations and the drawings do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation, and among them:

[0023] Figure 1 is a schematic structural diagram of a chiller provided by an embodiment of the present disclosure;

[0024] Figure 2It is a schematic diagram of a compressor control method for a chiller provided by an embodiment of the present disclosure;

[0025] Figure 3 It is another schematic diagram of a compressor control method for a chiller provided by an embodiment of the present disclosure;

[0026] Figure 4 It is another schematic diagram of a compressor control method for a chiller provided by an embodiment of the present disclosure;

[0027] Figure 5 It is another schematic diagram of a compressor control method for a chiller provided by an embodiment of the present disclosure;

[0028] Figure 6 It is an application schematic diagram of an embodiment of the present disclosure;

[0029] Figure 7 It is a schematic diagram of a compressor control device for a chiller provided by an embodiment of the present disclosure.

[0030] Reference numerals:

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

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

[0033] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are only for reference and explanation purposes and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of explanation, numerous details are provided to give a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be practiced without these details. In other instances, well-known structures and devices may be shown in a simplified manner to simplify the drawings.

[0034] The terms "first", "second", etc. in the description and claims of the embodiments of the present disclosure and the above-mentioned drawings are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data may be interchanged under appropriate circumstances so as to implement the embodiments of the present disclosure described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0035] Unless otherwise specified, the term "plural" means two or more.

[0036] In the embodiments of the present disclosure, the character " / " indicates an "or" relationship between the preceding and following objects. For example, A / B means: A or B.

[0037] The term "and / or" is an associative relationship describing an object, indicating that there can be three relationships. For example, A and / or B means: A or B, or, A and B, these three relationships.

[0038] The term "corresponding" may refer to an associative relationship or a binding relationship. A corresponding to B means that there is an associative relationship or a binding relationship between A and B.

[0039] Combined with Figure 1 As shown, the embodiments of the present disclosure provide a chiller 10. The chiller 10 includes an evaporator group 101, a compressor system, and a condenser 103. The evaporator group 101 includes a plurality of evaporators connected in series along the flow direction of the chilled water. The compressor system includes a plurality of compressor units 1021, and the condenser 103 is respectively connected to each evaporator through different compressor units 1021.

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

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

[0042] Based on the above system structure of the chiller, combined with Figure 2 As shown, the embodiments of the present disclosure provide a compressor control method for a chiller, including:

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

[0044] S02, when the chilled water inlet temperature meets the compressor startup condition, the chiller determines the number of compressors operating in the target compressor unit according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigerating capacity of the compressor in the target compressor unit. Among them, the target compressor unit is determined by the compressor startup condition.

[0045] S03, the chiller controls the startup and operation of the target compressor unit according to the number of compressors operating.

[0046] Using the compressor control method for a chiller provided by the embodiments of the present disclosure, when the chiller operates in the refrigeration mode, the embodiments of the present disclosure first obtain the chilled water inlet temperature, the actual chilled water outlet temperature, and the lower limit threshold of the evaporation temperature of each compressor unit. If the chilled water inlet temperature meets the compressor startup condition, the number of operating compressors of the target compressor is calculated according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigeration capacity of the target compressor unit, and the target compressor unit is controlled to start and operate according to the operating data. The embodiments of the present disclosure select the target compressor unit based on the chilled water inlet temperature and accurately determine the number of operating compressors of the target compressor unit by comprehensively considering the lower limit threshold of the evaporator temperature of the target compressor unit and the refrigeration capacity of the compressor, so as to determine the target compressor unit that can reach the target chilled water outlet temperature and is adapted to the specific chilled water inlet temperature value from the compressor system. Based on this, the embodiments of the present disclosure can obtain a chilled water outlet temperature with a larger temperature range under the condition of sharing the condenser in the refrigeration mode.

[0047] In addition, in the embodiments of the present disclosure, the structure form of sharing the condenser is adopted. Compared with the structure of a single condenser in the related art, the system structure is simpler and the adjustment effect of the chilled water outlet temperature is better.

[0048] Optionally, the chiller determines whether the chilled water inlet temperature meets the compressor startup condition and determines the target compressor in the following manner:

[0049] When 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, the chiller determines that the chilled water inlet meets the compressor startup condition and determines the first compressor unit as the target compressor unit.

[0050] When 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 startup condition 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] In this way, 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 refrigeration scenario of the chiller. The embodiments of the present disclosure do not specifically limit this.

[0060] Optionally, the refrigerating capacity of the compressor represents the refrigerating capacity of a single compressor of the compressor unit. The chiller determines the number of compressors in operation of the target compressor unit according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigerating capacity of the compressor of the target compressor unit, including:

[0061] The chiller determines the number of compressors in operation of the target compressor unit.

[0062] Wherein, when 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 N-th compressor, ΔT = T N-1 - T, and Q j = Q N .

[0065] 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 a proportionality coefficient, and z is 2,..., N - 1. α is determined according to the compressor configuration of the chiller compressor unit.

[0066] In this way, when the compressor units are all configured with multiple parallel-connected and same-type compressors, the greater the difference between the chilled water inlet temperature and the lower limit threshold of the evaporation temperature of a certain first compressor unit, the greater the number of compressors in operation required for the target compressor unit. At the same time, the greater the difference between T z-1 and T z , the greater the number of compressors in operation required for the target compressor. In addition, the lower the refrigerating capacity of a single compressor, the greater the number of compressors in operation required for the target compressor. That is, the number of compressors in operation is approximately in a proportional relationship with the difference between T i and T1, and the number of compressors in operation is also approximately in a proportional relationship with the difference between T z-1 and T zThe difference is in a direct proportional relationship, and the number of compressors in operation is also in an inverse proportional relationship with the refrigerating capacity of a single compressor in the compressor unit. Considering the above-mentioned multiple factors, after determining the target compressor unit in the chiller of the present disclosure, the chiller calculates the number of compressors in operation of the compressor unit according to the value of the chilled water inlet temperature, the lower limit threshold of the evaporator temperature of the target compressor unit, and the refrigerating capacity of a single compressor of the target compressor unit, so as to accurately obtain the number of compressors in operation of the target compressor unit that reaches the target chilled water outlet temperature and is adapted to the chilled water inlet temperature, thereby obtaining a chilled water outlet temperature with a larger temperature range in the refrigeration mode and when the condenser is shared.

[0067] Optionally, the chiller determines the number of compressors in operation of the target compressor unit according to including: the chiller determines the number of compressors in operation of the target compressor unit according to to determine the number of compressors in operation of the target compressor unit. Wherein, [·] is the rounding symbol, which is used to indicate that the calculation result is rounded to the nearest integer.

[0068] Based on the above system structure of the chiller, combined with Figure 3 as shown, the present disclosure also provides a compressor control method for a chiller, including:

[0069] S11. When the chiller operates in the refrigeration mode, the chiller obtains the chilled water inlet temperature, the actual chilled water outlet temperature, and 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 condition, the chiller determines the number of compressors in operation of the target compressor unit according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigerating capacity of the compressor of the target compressor unit. Wherein, the target compressor unit is determined by the compressor start-up condition.

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

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

[0073] Using the compressor control method for a chiller provided by the embodiments of the present disclosure, the embodiments of the present disclosure select a target compressor unit based on the chilled water inlet temperature and accurately determine the number of compressors in operation of the target compressor unit by comprehensively considering its lower limit threshold of the evaporator temperature of the target compressor unit and the refrigerating capacity of the compressor, so as to determine a target compressor unit adapted to a specific chilled water inlet temperature value from the compressor system. After controlling the start and operation of the target compressor according to the number of compressors in operation, there may still be a situation where the number of compressors in operation is too large or too small. To avoid an unreasonable number of compressors in operation, the embodiments of the present disclosure continue to determine whether the chilled water outlet temperature meets the loading and unloading conditions, and perform the unit loading and unloading operation on the target compressor when it meets the conditions, so as to obtain a chilled water outlet temperature with a larger temperature range while sharing the refrigeration mode and the condenser, and ensure that the chilled water outlet temperature accurately reaches the target chilled water outlet temperature. At the same time, the operating energy consumption of the chiller is reduced.

[0074] Combined with Figure 4 As shown, when the actual chilled water outlet temperature meets the compressor loading and unloading conditions, the chiller performs the unit loading and unloading operation on the target compressor unit, including:

[0075] S21. When the target compressor unit is the s-th compressor unit, 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, the chiller performs the unit unloading operation on the s-th compressor unit.

[0076] S22. When the target compressor is the s-th compressor unit, 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 and less than the sum value of the lower limit threshold of the s-th evaporation temperature and the second temperature deviation, the chiller performs the unit loading operation on the s-th compressor unit.

[0077] S23. When the target compressor is the N-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, the chiller performs the unit unloading operation on the N-th compressor unit.

[0078] S24. When the target compressor is 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 value of the target chilled water outlet temperature and the second temperature deviation, the chiller performs the unit loading operation on the N-th compressor unit.

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

[0080] Thus, when the target compressor unit is the s-th compressor unit, 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 running in the s-th compressor unit is relatively high. At this time, a unit unloading operation is performed on it. When the target compressor is the s-th compressor unit, 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 and 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 running in the s-th compressor unit is relatively low. At this time, a unit loading operation is performed on it. When the target compressor is the N-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, it indicates that the actual chilled water outlet temperature is relatively low and the number of compressors running in the N-th compressor unit is relatively high. At this time, a unit unloading operation is performed on it. When the target compressor is 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, it indicates that the actual chilled water outlet temperature is relatively high and the number of compressors running in the N-th compressor unit is relatively low. At this time, 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 refrigeration scenario of the chiller. The embodiments of the present disclosure do not make specific limitations on this.

[0082] Optionally, when the actual chilled water outlet temperature meets the conditions for compressor loading and unloading, the chiller performs a unit loading and unloading operation on the target compressor unit, and further includes:

[0083] When the target compressor is the s-th compressor unit, if 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, the chiller keeps the s-th compressor unit running continuously.

[0084] When the target compressor is 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, the chiller keeps the N-th compressor unit running continuously.

[0085] In this way, when the target compressor is the s-th compressor unit, if 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, it indicates that the actual chilled water temperature is within the appropriate temperature range. At this time, no loading or unloading operation is required. When the target compressor is 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, it indicates that the actual chilled water temperature is within the appropriate temperature range. At this time, no loading or unloading operation is required.

[0086] Optionally, as shown in Figure 5 the chiller performs a unit loading and unloading operation on the target compressor unit, including:

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

[0088] S32, the chiller 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 performs a unit unloading operation on the first target compressor, or performs a unit loading operation on the second target compressor.

[0090] In this way, the embodiment of the present disclosure confirms the target compressor according to the running time of each compressor in the target compressor unit, specifically unloads the one with the longest running time and loads the one with the shortest running time. Through the above loading and unloading method, a stable and reliable transition of loading and unloading can be achieved.

[0091] In practical applications, as shown in Figure 1 and Figure 6 N is 3, and the evaporator group includes a first evaporator, a second evaporator, and a third evaporator connected in series in sequence along the chilled water flow direction. 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.

[0092] The compressor control method for the chiller specifically performs the following steps:

[0093] S41, when the chiller operates in the refrigeration mode, the chiller obtains the chilled water inlet temperature T i and the actual chilled water outlet temperature T o , and the lower limit threshold of the evaporation temperature of each compressor unit.

[0094] S42, when T i ≥ T1 + t0, the chiller 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 operating 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 load addition or subtraction operation on the first compressor unit.

[0100] S48, the chiller loads the compressor with the shortest operating 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 operating 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 load addition or subtraction operation on the second compressor unit.

[0104] S52, The chiller performs a loading operation on the compressor with the shortest running time in the second compressor unit.

[0105] S53 , The chiller determines whether T o ≤ T - t1 holds. If it holds, S54 is executed; otherwise, S55 is executed.

[0106] S54, The chiller performs an unloading operation on the compressor with the longest running time in the third compressor unit.

[0107] S55, The chiller determines whether T - t1 < T o ≤ T + t1 holds. If it holds, S56 is executed; otherwise, no loading or unloading operation is performed on the third compressor unit.

[0108] S56, The chiller performs a loading operation on the compressor with the shortest running time in the third compressor unit.

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

[0110] In addition, when the logical instructions in the above-mentioned memory 701 are implemented in the form of a software functional unit and sold or used as an independent product, they 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 the program instructions / modules corresponding to the method in the embodiment of the present disclosure. The processor 700 executes functional applications and data processing by running the program instructions / modules stored in the memory 701, that is, implements the compressor control method for the chiller in the above embodiment.

[0112] The memory 701 may include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the terminal device, etc. In addition, the memory 701 may include a high-speed random access memory and may also include a non-volatile memory.

[0113] Combined Figure 1 As shown, an embodiment of the present disclosure provides a chiller 10, including: a product body and the above-mentioned compressor control device 70 for the chiller. The compressor control device 70 for the chiller is installed on the unit body. The installation relationship described here is not limited to being placed inside the unit body, but also includes installation connections with other components of the chiller 10, including but not limited to physical connections, electrical connections, or signal transmission connections, etc. Those skilled in the art can understand that the compressor control device 70 for the chiller can be adapted to a feasible unit body, thereby implementing other feasible embodiments.

[0114] An embodiment of the present disclosure provides a computer-readable storage medium storing computer-executable instructions, and the computer-executable instructions are set to execute the above-mentioned compressor control method for the chiller.

[0115] The technical solution of the embodiment of the present 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 for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiment of the present disclosure. The foregoing storage medium may be a non-transitory storage medium, such as: a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk, or an optical disc, etc., which are various media that can store program codes.

[0116] The above description and the accompanying drawings fully illustrate the embodiments of the present disclosure, enabling those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process, and other changes. The embodiments merely represent possible variations. Unless explicitly required, individual components and functions are optional, and the order of operations may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terms used in this application are only for describing the embodiments and do not limit the claims. As used in the description of the embodiments and the claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to also include the plural forms. Similarly, as used in this application, the term "and / or" refers to any and all possible combinations including one or more of the associated listed items. Additionally, when used in this application, the term "comprise" and its variants "comprises" and / or "comprising" etc. mean the presence of the stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups of these. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, or apparatus including the element. Herein, each embodiment may focus on the differences from other embodiments, and the same or similar parts among the embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method parts disclosed in the embodiments, the relevant parts may refer to the description of the method parts.

[0117] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner may depend on the specific application and design constraints of the technical solution. The technical personnel can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the embodiments of the present disclosure. The technical personnel can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0118] In the embodiments disclosed herein, the disclosed methods, products (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units can be merely a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the shown or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of devices or units can be in electrical, mechanical, or other forms. The units described as separate components can be or can not be physically separated. The components shown as units can be or can not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to implement this embodiment. Additionally, in the embodiments of the present disclosure, the various functional units can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit.

[0119] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions marked in the blocks can occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, which can depend 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 can also occur in a different order than that disclosed in the description. Sometimes, there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, which can depend on the functions involved. Each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A compressor control method for a chiller, characterized in that, The chiller includes an evaporator group, a compressor system, and a condenser. The evaporator group includes a plurality of evaporators connected in series along the flow direction of the chilled water. The compressor system includes a plurality of compressor units, and the condenser is connected to each evaporator through different compressor units respectively. The control method includes: When the chiller operates in the refrigeration mode, obtain the chilled water inlet temperature, the actual chilled water outlet temperature, and the lower limit threshold of the evaporation temperature of each compressor unit. When the chilled water inlet temperature meets the compressor startup condition, determine the number of compressors running in the target compressor unit according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigerating capacity of the compressor in the target compressor unit, where the target compressor unit is determined by the compressor startup condition. Control the startup and operation of the target compressor unit according to the number of compressors running.

2. The control method according to claim 1, characterized in that The evaporator group includes a first evaporator, a second evaporator,..., an Nth evaporator connected in series in sequence along the flow direction of the chilled water. The mth compressor unit is respectively connected to the mth evaporator. Determine whether the chilled water inlet temperature meets the compressor startup condition and determine the target compressor in the following way: When 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, determine that the chilled water inlet meets the compressor startup condition, and determine the first compressor unit as the target compressor unit. When the chilled water inlet temperature is greater than or equal to the sum of the lower limit threshold of the mth 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, determine that the chilled water inlet meets the compressor startup condition, and determine the mth compressor unit as the target compressor unit. Among them, the lower limit threshold of the mth evaporator temperature represents the lower limit value of the evaporation temperature of the mth compressor unit, and m is negatively correlated with the lower limit threshold of the mth evaporator temperature, where m = 2,..., N.

3. The control method according to claim 2, characterized in that Each compressor unit includes a plurality of compressors connected in parallel and of the same model. The refrigerating capacity of the compressor represents the refrigerating capacity of a single compressor in the compressor unit. Determine the number of compressors running in the target compressor unit according to the chilled water inlet temperature, the lower limit threshold of the evaporation temperature of the target compressor unit, and the refrigerating capacity of the compressor in the target compressor unit, including: According to Determine the number of compressors in operation of the target compressor unit; Wherein, when 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 = Q N ; T z and T respectively represent the lower limit threshold of the evaporation temperature of the z-th compressor unit and the target outlet water temperature of the chilled water. T1 represents the lower limit threshold of the evaporation temperature of the first compressor unit, and T i represents the inlet water temperature of the chilled water, and 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.

4. The control method according to claim 2, wherein It also includes: After controlling the startup and operation of the target compressor unit according to the number of compressors running, obtain the target chilled water outlet temperature. When the actual chilled water outlet temperature meets the compressor loading / unloading condition, perform the unit loading / unloading operation on the target compressor unit.

5. The control method according to claim 4, characterized in that, When the actual chilled water outlet temperature meets the compressor loading / unloading condition, perform the unit loading / unloading operation on the target compressor unit, including: When the target compressor unit is the sth compressor unit, if the actual chilled water outlet temperature is less than or equal to the difference between the lower limit threshold of the sth evaporation temperature and the second temperature deviation, perform the unit unloading operation on the sth compressor unit. When the target compressor is the sth compressor unit, if the actual chilled water outlet temperature is greater than the difference between the lower limit threshold of the sth evaporation temperature and the second temperature deviation and less than the sum of the lower limit threshold of the sth evaporation temperature and the second temperature deviation, perform the unit loading operation on the sth compressor unit. When the target compressor is the Nth 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, perform a unit unloading operation on the Nth compressor unit; When the target compressor is the Nth 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, perform a unit loading operation on the Nth compressor unit; where s is 1, 2,..., N - 1.

6. The control method according to claim 5, wherein It further includes: When the target compressor is the s-th compressor unit, if 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, keep the s-th compressor unit running continuously; When the target compressor is the Nth 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, keep the Nth compressor unit running continuously.

7. The control method according to claim 4, wherein Performing a unit loading and unloading operation on the target compressor unit includes: Obtaining the running duration of each compressor in the target compressor unit; Determining the compressor with the longest running duration as the first target compressor and the compressor with the shortest running duration as the second target compressor; Performing a unit unloading operation on the first target compressor, or performing a unit loading operation on the second target compressor.

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

9. A chiller, characterized in that, It includes: A unit body, including: an evaporator group and a condenser, a compressor system. The evaporator group includes a plurality of evaporators connected in series along the chilled water flow direction. The compressor system includes a plurality of compressor units, and the condenser is connected to each evaporator through different compressor units respectively; and The compressor control device for a chiller as described in claim 8 is installed on the unit body.

10. The chiller according to claim 9, characterized in that, Each compressor unit includes a plurality of compressors of the same model connected in parallel.

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