CN113983712B

CN113983712B - Unit operation control method and device, two-stage unit and refrigeration equipment

Info

Publication number: CN113983712B
Application number: CN202111234426.XA
Authority: CN
Inventors: 周巍; 龙忠铿; 罗炽亮; 练浩民; 李莹; 孟俣
Original assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai
Current assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai
Priority date: 2021-10-22
Filing date: 2021-10-22
Publication date: 2023-05-02
Anticipated expiration: 2041-10-22
Also published as: CN113983712A

Abstract

The invention discloses a unit operation control method and device, a two-stage unit and refrigeration equipment. Wherein, doublestage unit is including condenser, expansion valve and the cooling air unit of intercommunication in proper order, still includes: the system comprises a first-stage compressor unit and a second-stage compressor unit which are arranged in series, wherein the air suction end of the first-stage compressor unit is communicated with the outlet end of the cold air unit, the air discharge end of the first-stage compressor unit is communicated with the air suction end of the second-stage compressor unit, and the air suction end of the second-stage compressor unit is also communicated with the outlet end of the cold air unit, and the method comprises the following steps: acquiring the evaporation temperature of the two-stage unit; and controlling the operation states and the operation capacities of the primary compressor unit and the secondary compressor unit according to the evaporation temperature and the freezing point temperature of the storage in the refrigeration equipment. The invention can realize quick phase transition and keep the highest energy efficiency of the two-stage unit all the time.

Description

Unit operation control method and device, two-stage unit and refrigeration equipment

Technical Field

The invention relates to the technical field of units, in particular to a unit operation control method and device, a two-stage unit and refrigeration equipment.

Background

With the improvement of living standard, the demand for quick-frozen foods is increasing. A food product stored in a refrigeration appliance, the freezing process of which comprises a phase change phase, a cooling phase and a freezing phase. The phase change stage is the main occurrence stage of ice crystal formation of food, namely the maximum ice crystal formation stage, and the long duration of the phase change stage can affect the food freezing quality, so in order to shorten the duration of the phase change stage, quick freezing (short for quick freezing) at low temperature is needed to realize quick passing through the phase change stage, so that the food quality is better kept. The unit adopted by general quick freezing adopts a two-stage unit, the capacity adjustment and the internal volume ratio adjustment range of the prior two-stage compressor are limited, and the capacity of the two-stage unit can not be adjusted according to the freezing characteristic of stored food, so that the duration time of the food phase change stage is longer, and the energy efficiency is lower.

Aiming at the problems that the two-stage unit in the prior art cannot adjust the capacity of the two-stage compressor according to the freezing characteristic of stored food, so that the duration time of the food phase change stage is longer and the energy efficiency is lower, no effective solution is proposed at present.

Disclosure of Invention

The embodiment of the invention provides a unit operation control method, a unit operation control device, a two-stage unit and refrigerating equipment, which are used for solving the problems that in the prior art, the two-stage unit does not adjust the capacity of a two-stage compressor according to the freezing characteristic of stored food, so that the duration time of a food phase change stage is longer and the energy efficiency is lower.

In order to solve the technical problems, the invention provides a unit operation control method, which is applied to refrigeration equipment with a two-stage unit, wherein the two-stage unit comprises a condenser, an expansion valve and a cold air unit which are sequentially communicated, and the two-stage unit further comprises: the system comprises a first-stage compressor unit and a second-stage compressor unit which are arranged in series, wherein the air suction end of the first-stage compressor unit is communicated with the outlet end of the cold air unit, the air discharge end of the first-stage compressor unit is communicated with the air suction end of the second-stage compressor unit, and the air suction end of the second-stage compressor unit is also communicated with the outlet end of the cold air unit.

Acquiring the evaporation temperature of the two-stage unit;

and controlling the operation states and the operation capacities of the primary compressor unit and the secondary compressor unit according to the evaporation temperature and the freezing point temperature of the storage in the refrigeration equipment.

Further, obtaining an evaporation temperature of the two-stage unit includes:

acquiring the evaporation pressure of the two-stage unit;

determining a corresponding evaporation temperature according to the evaporation pressure; wherein the evaporation temperature and the evaporation pressure satisfy a preset corresponding relationship.

Further, controlling the operating states and the operating capacities of the primary compressor unit and the secondary compressor unit according to the evaporation temperature and the freezing point temperature of the storage in the refrigeration equipment, including:

if the evaporation temperature is greater than or equal to the freezing point temperature of the storage, controlling all compressors in the primary compressor unit to stop running, and simultaneously controlling all compressors in the secondary compressor unit to start running and loading to the maximum capacity;

if the evaporation temperature is smaller than the freezing point temperature of the storage object and is larger than or equal to a preset temperature value, only one compressor in the secondary compressor unit is controlled to operate according to a first preset capacity, and meanwhile the operation capacity of the primary compressor unit is adjusted according to the evaporation temperature and a target evaporation temperature;

if the evaporation temperature is smaller than the preset temperature value, adjusting the operation capacity of the primary compressor unit and the operation capacity of the secondary compressor unit according to the evaporation temperature and the target evaporation temperature;

wherein the preset temperature value is less than the freezing point temperature of the storage object.

Further, adjusting the operating capacity of the primary compressor unit according to the evaporating temperature and a target evaporating temperature, comprising:

acquiring a difference value between the evaporation temperature and a target evaporation temperature;

adjusting the operation capacity of the primary compressor unit according to the difference value between the evaporation temperature and the target evaporation temperature; wherein the operating capacity of the primary compressor unit is positively correlated to the difference.

Further, adjusting the operating capacity of the primary compressor unit and the operating capacity of the secondary compressor unit according to the evaporating temperature and the target evaporating temperature, comprising:

adjusting the operation capacity of the primary compressor unit according to the evaporation temperature and the target evaporation temperature;

and determining the operation capacity of the two-stage compressor unit according to the pressure ratio of the two-stage compressor unit and the operation capacity of the one-stage compressor unit.

Further, determining the operating capacity of the secondary compressor unit based on the operating capacity of the primary compressor unit and the pressure ratio of the dual-stage unit includes:

determining the optimal capacity ratio of the two-stage compressor unit to the one-stage compressor unit according to the pressure ratio of the two-stage compressor unit;

and determining the operation capacity of the secondary compressor unit according to the operation capacity of the primary compressor unit and the optimal capacity ratio.

The invention also provides a unit operation control device which is applied to refrigeration equipment with a two-stage unit, wherein the two-stage unit comprises a condenser, an expansion valve and a cold air unit which are sequentially communicated, and the two-stage unit further comprises: the one-stage compressor unit and the second grade compressor unit that establish ties set up, one-stage compressor unit, its inhale end with the exit end intercommunication of cooling air unit, its exhaust end with the inhale end intercommunication of second grade compressor unit, the inhale end of second grade compressor unit still with the exit end intercommunication of cooling air unit, unit operation controlling means includes:

the acquisition module is used for acquiring the evaporation temperature of the two-stage unit;

and the control module is used for controlling the operation states and the operation capacities of the primary compressor unit and the secondary compressor unit according to the evaporation temperature.

The invention also provides a two-stage unit, which comprises a condenser, an expansion valve and a cold air unit which are sequentially communicated, and further comprises:

a first-stage compressor unit and a second-stage compressor unit which are arranged in series;

the air suction end of the primary compressor unit is communicated with the outlet end of the cold air unit, the air discharge end of the primary compressor unit is communicated with the air suction end of the secondary compressor unit, the air suction end of the secondary compressor unit is also communicated with the outlet end of the cold air unit, and the air discharge end of the secondary compressor unit is communicated with the condenser.

Further, the two-stage unit further comprises the unit operation control device.

Further, the dual stage unit further includes: and the economizer is arranged between the condenser of the two-stage unit and the cold air unit and is also communicated with the air suction end of the two-stage compressor unit.

Further, the primary compressor unit comprises at least one compressor, the secondary compressor unit comprises at least one compressor, and when the number of the compressors of the primary compressor unit is more than two, different compressors are arranged in parallel; when the number of compressors in the two-stage compressor unit is more than two, different compressors are connected in parallel.

Further, the dual stage unit further includes: the high-pressure electromagnetic valve is arranged between the outlet end of the cold air unit and the air suction end of the secondary compressor unit.

The invention also provides refrigeration equipment comprising the two-stage unit.

The present invention also provides a computer-readable storage medium having stored thereon a computer program which when executed by a processor implements the above-described unit operation control method.

By adopting the technical scheme of the invention, the running states and the running capacities of the primary compressor unit and the secondary compressor unit are controlled according to the evaporating temperature of the two-stage unit and the freezing point temperature of the storage, so that the capacities of the primary compressor unit and the secondary compressor unit in the two-stage unit can be adjusted according to the freezing characteristics of stored foods, the quick passing phase transition stage is realized, and the two-stage unit always maintains the highest energy efficiency.

Drawings

FIG. 1 is a block diagram of a dual stage unit according to an embodiment of the present invention;

FIG. 2 is a flow chart of a unit operation control method according to an embodiment of the invention;

FIG. 3 is a block diagram of a unit operation control device according to an embodiment of the present invention;

fig. 4 is a block diagram of a control module according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plurality" generally includes at least two.

It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or device comprising such element.

Alternative embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

The embodiment provides a unit operation control method, which is applied to refrigeration equipment with a two-stage unit, fig. 1 is a structural diagram of the two-stage unit according to an embodiment of the invention, as shown in fig. 1, the two-stage unit comprises a first-stage compressor unit 1 and a second-stage compressor unit 2 which are arranged in series, in this embodiment, the first-stage compressor unit 1 is a low-pressure stage compressor unit, wherein the first-stage compressor unit comprises n low-pressure compressors 11-1 n, the second-stage compressor unit 2 is a high-pressure stage compressor unit, the first-stage compressor unit comprises m high-pressure compressors 21-2 m, the two-stage unit further comprises a condenser 3, an expansion valve V1 and a cold air unit 4 which are sequentially communicated, the expansion valve V1 can be further connected with a main electromagnetic valve V2 in series, an air suction end of the first-stage compressor unit 1 is communicated with an outlet end of the cold air unit 4, an air suction end of the second-stage compressor unit 2 is further communicated with an outlet end of the cold air unit 4, and a high-pressure stage electromagnetic valve V6 is further arranged on a communicated pipeline. An air suction pressure sensor PT1 and a first temperature sensor TT1 are arranged at the outlet end of the cold air unit 4; an exhaust end of the first-stage compressor unit 1 is provided with an intermediate pressure sensor PT2 and a second temperature sensor TT2; an exhaust end of the secondary compressor unit 2 is provided with an exhaust pressure sensor PT3 and a third temperature sensor TT3.

When the number of compressors of the first-stage compressor unit is more than two, different compressors are connected in parallel; when the number of compressors in the two-stage compressor unit is more than two, different compressors are connected in parallel.

The unit further comprises an economizer 5, the economizer 5 is arranged between the condenser 3 of the two-stage unit and the cold air unit 4, the economizer 5 is further communicated with the air suction end of the two-stage compressor unit 2, a branch where the economizer 5 is arranged is connected with a bypass branch in parallel between the condenser 3 of the two-stage unit and the cold air unit 4, an economizer throttle valve V3 and an economizer electromagnetic valve V4 are arranged on the branch where the economizer 5 is arranged, and a bypass electromagnetic valve V5 is arranged on the bypass branch.

Fig. 2 is a flowchart of a unit operation control method according to an embodiment of the present invention, as shown in fig. 2, the method includes:

s101, acquiring the evaporation temperature of the two-stage unit.

Because the evaporating temperature and the evaporating pressure of the same refrigerant have a corresponding relation, the corresponding relation can be recorded in a form of a table, and when the method is implemented, the evaporating pressure P can be detected through the air suction pressure sensor PT1 arranged at the outlet end of the cold air unit 4, and the corresponding evaporating temperature T can be found in the table according to the evaporating pressure P after the evaporating pressure P of the two-stage unit is obtained.

S102, controlling the operation states and the operation capacities of the primary compressor unit and the secondary compressor unit according to the evaporation temperature and the freezing point temperature of the storage in the refrigeration equipment.

According to the unit operation control method, the operation states and the operation capacities of the first-stage compressor unit and the second-stage compressor unit are controlled according to the evaporation temperature of the two-stage unit and the freezing point temperature of the storage object, the capacities of the first-stage compressor unit and the second-stage compressor unit in the two-stage unit can be adjusted according to the freezing characteristics of the storage food, the quick passing phase-change stage is realized, and the two-stage unit always keeps the highest energy efficiency.

Example 2

The embodiment provides another unit operation control method, in order to adjust the capacity of the two-stage unit according to the freezing characteristic of the stored food, the step S102 specifically includes: if the evaporating temperature is greater than or equal to the freezing point temperature of the storage object, the phase change stage is about to be started, the current refrigeration requirement is large, the capacity of the required compressor is large and the efficiency is high, so that all compressors in the primary compressor unit are controlled to stop running, and all compressors in the secondary compressor unit are controlled to start running and are loaded to the maximum capacity; if the evaporation temperature is less than the freezing point temperature of the storage object and is greater than or equal to a preset temperature value, the phase change stage is indicated to be entered at present, but the refrigeration requirement is smaller, at the moment, only one compressor in the two-stage compressor unit is controlled to operate according to a first preset capacity (the first preset capacity can be the maximum capacity of the compressor or 50% equivalent), and meanwhile, the operation capacity of the one-stage compressor unit can be adjusted according to the evaporation temperature and the target evaporation temperature; if the evaporation temperature is smaller than the preset temperature value, the phase change stage is finished, the current refrigeration requirement is particularly small, and the operation capacity of the primary compressor unit and the operation capacity of the secondary compressor unit are adjusted according to the evaporation temperature and the target evaporation temperature, so that the refrigeration requirement can be met, and the operation can avoid the unnecessary increase of the capacity of the compressor so as to realize the highest energy efficiency; the predetermined temperature value is less than the freezing point temperature of the storage object.

In order to achieve accurate control of the capacity of the primary compressor unit according to the current refrigeration capacity demand, adjusting the operating capacity of the primary compressor unit according to the evaporating temperature and the target evaporating temperature, comprising: obtaining a difference value between the evaporation temperature and a target evaporation temperature; adjusting the operation capacity of the first-stage compressor unit according to the difference value between the evaporation temperature and the target evaporation temperature; wherein the operating capacity of the primary compressor unit is positively correlated to the difference. For example, in implementation, one compressor in the first-stage compressor unit may be controlled to start and operate according to the second preset capacity, where the evaporating temperature is higher than the target evaporating temperature, and since both the evaporating temperature and the target evaporating temperature are negative values, the difference between the evaporating temperature and the target evaporating temperature is a positive value, and the larger the value is, which indicates that the larger the difference between the current evaporating temperature and the target evaporating temperature is, the larger the operating capacity of the first-stage compressor unit needs to be increased, and if the capacity of the currently operating compressor has reached the maximum capacity, more compressors need to be controlled to start to operate, so as to further improve the operating capacity of the entire first-stage compressor unit.

If the evaporation temperature is smaller than the preset temperature value, the phase change stage is completed, the current refrigeration requirement is extremely small, and in order to realize the highest energy efficiency, the operation capacity of the primary compressor unit and the operation capacity of the secondary compressor unit need to be further controlled according to the actual refrigeration requirement, specifically, the operation capacity of the primary compressor unit and the operation capacity of the secondary compressor unit are adjusted according to the evaporation temperature and the target evaporation temperature, including: the operation capacity of the first-stage compressor unit is regulated according to the evaporation temperature and the target evaporation temperature, wherein the specific regulation method is the same as the regulation method of the operation capacity of the first-stage compressor unit when the evaporation temperature is smaller than the freezing point temperature of the storage object and is larger than or equal to a preset temperature value, namely the operation capacity of the first-stage compressor unit is positively correlated with the difference value, and the larger the difference value is, the larger the operation capacity of the first-stage compressor unit is; and then determining the operation capacity of the two-stage compressor unit according to the pressure ratio of the two-stage compressor unit and the operation capacity of the one-stage compressor unit. The method specifically comprises the following steps: determining an optimal capacity ratio of the two-stage compressor unit to the one-stage compressor unit according to a pressure ratio of the two-stage unit (namely, a ratio of exhaust pressure to suction pressure of the two-stage unit); and determining the operation capacity of the secondary compressor unit according to the operation capacity of the primary compressor unit and the optimal capacity ratio. The optimal capacity ratio and the pressure ratio of the two-stage unit have a corresponding relation, and a specific corresponding relation can be obtained in advance through experiments, so that the optimal capacity ratio of the two-stage compressor unit and the one-stage compressor unit under different pressure ratios can be measured to form a corresponding relation table.

The invention is described in detail below in connection with a specific example:

in specific implementation, firstly, the evaporating pressure P of the two-stage unit is detected, the corresponding evaporating temperature T is determined in a table look-up mode, and when T is more than or equal to the solidifying point temperature T1 of the storage, all high-pressure compressors are started and sequentially loaded to the maximum capacity. The low-pressure steam from the outlet end of the cold air unit 4 is compressed by a high-pressure stage compressor, enters a condenser 3 for condensation, the condensed liquid enters the cold air unit 4 after passing through a branch circuit where an economizer is located and being throttled by a main thermal expansion valve V2, the cold air unit 4 is arranged in a storage space of refrigeration equipment, and a refrigerant in a pipeline absorbs heat of a storage object and evaporates into low-pressure steam to enter the next refrigeration cycle. The following table 1 is a statistical table of the opening and closing conditions of each electromagnetic valve when T is more than or equal to T1.

Table 1T is greater than or equal to T1, statistics of opening and closing conditions of each valve

When the evaporating temperature T is less than the solidifying point temperature T1 of the storage, the capacity of the high-grade compressor is unloaded, the high-pressure-grade electromagnetic valve V6 is closed, but 1 high-pressure-grade compressor is ensured to be started, one low-pressure-grade compressor is started at the same time, and the loading and the opening increasing control of the low-pressure-grade compressor are carried out according to the difference value of the evaporating temperature T and the target evaporating temperature Te. The refrigeration cycle process is as follows: the low-pressure steam from the air cooler unit 4 is compressed by the low-pressure stage compressor, enters the high-pressure stage compressor together with flash gas discharged by the economizer 5 for compression, and the compressed high-pressure gas is condensed by the condenser 3, enters the economizer through the economizer throttle valve V3, and enters the high-pressure stage compressor together with low-pressure stage exhaust for compression. The liquid enters a condenser 3 to be condensed. Table 2 below shows statistics of the opening and closing conditions of the electromagnetic valves when T < T1.

Table 2 statistics of opening and closing conditions of each valve when T < t1

Valve name	Opening device	Switch for closing
			High-pressure electromagnetic valve V6		√
Bypass solenoid valve V5		√
			Economizer solenoid valve V4	√
Main electromagnetic valve V2	√

When the evaporating temperature T (evaporating temperature) is less than-30 ℃, determining the optimal capacity ratio of the primary compressor unit and the secondary compressor unit according to the pressure ratio (exhaust pressure/suction pressure) of the two-stage unit, and loading and opening increasing the low-pressure stage compressor in the primary compressor unit according to the evaporating temperature T and the target evaporating temperature Te by the primary compressor unit. And determining the operation capacity of the secondary compressor unit according to the optimal capacity ratio of the primary compressor unit to the secondary compressor unit and the operation capacity of the primary compressor unit, and performing capacity adjustment on a single high-pressure stage compressor in the secondary compressor unit according to the operation capacity of the secondary compressor unit, wherein the refrigeration cycle process and the valve opening are consistent with those when the evaporation temperature T is less than the freezing point temperature of the stored matters.

The number of the low-pressure stage compressors started in the first-stage compressor unit is n, and the running capacities are a%, b% and 100% respectively. Wherein, the number of compressors with the running capacity of a% is na, the number of compressors with the running capacity of b% is nb, and the number of compressors with the running capacity of 100% is nc. The operating capacity of the primary compressor group = (na x a% + nb x b% + nc)/n.

The number of the high-pressure compressors started in the two-stage compressor unit is m, and the running capacities are c%, d% and 100% respectively. Wherein, the number of compressors with the running capacity of c% is mc, the number of compressors with the running capacity of d% is md, and the number of compressors with the running capacity of 100% is me. The operating capacity of the secondary compressor group= (mc c% + md% + me)/m.

In the specific control, the total operation capacity of the whole primary compressor unit or the total operation capacity of the secondary compressor unit is controlled to meet a preset value, and the capacity adjustment of the whole compressor unit can be realized by adjusting the capacity of any running compressor.

Example 3

The present embodiment provides a unit operation control device applied to a refrigeration apparatus having a two-stage unit including, as shown in fig. 1 mentioned hereinabove, a condenser 3, an expansion valve V1, and a cooling air unit 4 which are sequentially communicated, the two-stage unit further including: the first-stage compressor unit 1 and the second-stage compressor unit 2 that the series arrangement, the air-suction end of the first-stage compressor unit 1 communicates with the exit end of the cold air unit 4, the air-discharge end of the first-stage compressor unit 1 communicates with the air-suction end of the second-stage compressor unit 2, the air-suction end of the second-stage compressor unit 2 also communicates with the exit end of the cold air unit 4, fig. 3 is a block diagram of a unit operation control device according to an embodiment of the present invention, as shown in fig. 3, the control device includes: an acquisition module 10, configured to acquire an evaporation temperature of the two-stage unit; the control module 20 is used for controlling the operation states and the operation capacities of the primary compressor unit and the secondary compressor unit according to the evaporation temperature.

According to the unit operation control device, through the control module 20, the operation states and the operation capacities of the primary compressor unit and the secondary compressor unit are controlled according to the evaporation temperature of the two-stage unit and the freezing point temperature of a storage object, the capacities of the primary compressor unit and the secondary compressor unit in the two-stage unit can be adjusted according to the freezing characteristics of stored foods, the quick passing phase change stage is realized, and the two-stage unit always keeps the highest energy efficiency.

Example 4

In this embodiment, another unit operation control device is provided, fig. 4 is a block diagram of a control module according to an embodiment of the present invention, and in order to implement adjustment of capacity of a two-stage unit for freezing characteristics of stored food, as shown in fig. 4, the control module 20 includes:

the first control unit 201 is configured to control all compressors in the first-stage compressor unit to stop operating when the evaporation temperature is greater than or equal to the freezing point temperature of the storage object, and simultaneously control all compressors in the second-stage compressor unit to start operating and load to a maximum capacity. The evaporating temperature is greater than or equal to the freezing point temperature of the storage object, which indicates that the phase change stage is about to be entered, the current refrigeration requirement is large, the capacity of the required compressor is large and the efficiency is high, so that all compressors in the primary compressor unit are controlled to stop running, and all compressors in the secondary compressor unit are controlled to start running and loading to the maximum capacity.

And the second control unit 202 is configured to control only one compressor in the secondary compressor unit to operate according to the first preset capacity when the evaporation temperature is less than the freezing point temperature of the storage object and greater than or equal to the preset temperature value, and to adjust the operation capacity of the primary compressor unit according to the evaporation temperature and the target evaporation temperature. The evaporating temperature is smaller than the freezing point temperature of the storage object and is larger than or equal to the preset temperature value, which indicates that the phase change stage is entered at present, but the refrigerating demand is smaller, at the moment, only one compressor in the two-stage compressor unit is controlled to operate according to the first preset capacity (the first preset capacity can be the maximum capacity of the compressor or 50% equivalent), and meanwhile, the operating capacity of the one-stage compressor unit can be adjusted according to the evaporating temperature and the target evaporating temperature.

And a third control unit 203, configured to adjust the operation capacity of the primary compressor unit and the operation capacity of the secondary compressor unit according to the evaporation temperature and the target evaporation temperature when the evaporation temperature is less than the preset temperature value. The evaporation temperature is smaller than a preset temperature value, the phase change stage is finished, the current refrigeration requirement is particularly small, the operation capacity of the primary compressor unit and the operation capacity of the secondary compressor unit are adjusted according to the evaporation temperature and the target evaporation temperature, so that the refrigeration requirement can be met, and the operation can avoid the unnecessary increase of the capacity of the compressor so as to realize the highest energy efficiency; the predetermined temperature value is less than the freezing point temperature of the storage object.

In order to achieve accurate control of the capacity of the primary compressor unit according to the current refrigeration capacity demand, the second control unit 202 is specifically configured to: obtaining a difference value between the evaporation temperature and a target evaporation temperature; adjusting the operation capacity of the first-stage compressor unit according to the difference value between the evaporation temperature and the target evaporation temperature; wherein the operating capacity of the primary compressor unit is positively correlated to the difference. For example, in implementation, one compressor in the first-stage compressor unit may be controlled to start and operate according to the second preset capacity, where the evaporating temperature is higher than the target evaporating temperature, and since both the evaporating temperature and the target evaporating temperature are negative values, the difference between the evaporating temperature and the target evaporating temperature is a positive value, and the larger the value is, which indicates that the larger the difference between the current evaporating temperature and the target evaporating temperature is, the larger the operating capacity of the first-stage compressor unit needs to be increased, and if the capacity of the currently operating compressor has reached the maximum capacity, more compressors need to be controlled to start to operate, so as to further improve the operating capacity of the entire first-stage compressor unit.

If the evaporation temperature is smaller than the preset temperature value, it indicates that the phase change stage is completed, the current refrigeration requirement is particularly small, and in order to achieve the highest energy efficiency, the operation capacity of the primary compressor unit and the operation capacity of the secondary compressor unit need to be further controlled according to the actual refrigeration requirement, and the third control unit 203 is specifically configured to: the operation capacity of the first-stage compressor unit is adjusted according to the evaporation temperature and the target evaporation temperature, wherein a specific adjustment method is the same as that of the first-stage compressor unit when the evaporation temperature is smaller than the freezing point temperature of the storage object and is larger than or equal to a preset temperature value, that is, the operation capacity of the first-stage compressor unit is positively correlated with the difference value, and the larger the difference value is, the larger the operation capacity of the first-stage compressor unit is; and then determining the operation capacity of the two-stage compressor unit according to the pressure ratio of the two-stage compressor unit and the operation capacity of the one-stage compressor unit. The method specifically comprises the following steps: determining an optimal capacity ratio of the two-stage compressor unit to the one-stage compressor unit according to a pressure ratio of the two-stage unit (namely, a ratio of exhaust pressure to suction pressure of the two-stage unit); and determining the operation capacity of the secondary compressor unit according to the operation capacity of the primary compressor unit and the optimal capacity ratio.

Example 5

The present embodiment provides a two-stage unit, as shown in fig. 1 mentioned above, which includes a condenser 3, an expansion valve V1, and a cooling air unit 4, which are sequentially communicated, further including: a primary compressor unit 1 and a secondary compressor unit 2 arranged in series; the air suction end of the primary compressor unit 1 is communicated with the outlet end of the cold air unit 4, the air discharge end of the primary compressor unit 1 is communicated with the air suction end of the secondary compressor unit 2, the air suction end of the secondary compressor unit 2 is also communicated with the outlet end of the cold air unit 4, and the air discharge end of the secondary compressor unit 2 is communicated with the condenser 3.

In this embodiment, the first-stage compressor unit 1 is a low-pressure stage compressor unit, which includes n low-pressure compressors 11-1 n, the second-stage compressor unit 2 is a high-pressure stage compressor unit, which includes m high-pressure compressors 21-2 m, the two-stage unit further includes a condenser 3, an expansion valve V1 and a cooling air unit 4 that are sequentially communicated, the expansion valve V1 may be further connected in series with a main electromagnetic valve V2, an air suction end of the first-stage compressor unit 1 is communicated with an outlet end of the cooling air unit 4, an air discharge end of the first-stage compressor unit 1 is communicated with an air suction end of the second-stage compressor unit 2, an air suction end of the second-stage compressor unit 2 is also communicated with an outlet end of the cooling air unit 4, and a high-pressure stage electromagnetic valve V6 is further disposed on a communicated pipeline. An air suction pressure sensor PT1 and a first temperature sensor TT1 are arranged at the outlet end of the cold air unit 4; an exhaust end of the first-stage compressor unit 1 is provided with an intermediate pressure sensor PT2 and a second temperature sensor TT2; an exhaust end of the secondary compressor unit 2 is provided with an exhaust pressure sensor PT3 and a third temperature sensor TT3.

The unit further comprises an economizer 5, the economizer 5 is arranged between the condenser 3 of the two-stage unit and the cold air unit 4, the economizer 5 is further communicated with the air suction end of the two-stage compressor unit 2, a branch where the economizer 5 is arranged is connected with the bypass branch in parallel between the condenser 3 of the two-stage unit and the cold air unit 4, an economizer throttle valve V3 and an economizer electromagnetic valve V4 are arranged on the branch where the economizer 5 is arranged, and a bypass electromagnetic valve V5 is arranged on the bypass branch.

The two-stage unit of the present embodiment may further include the unit operation control device in the foregoing embodiment.

Example 6

The embodiment provides refrigeration equipment, which comprises the two-stage unit in the embodiment, can realize quick passing phase change and always keeps the highest energy efficiency. In a specific implementation, the refrigerating device can be a refrigerator or a quick-freezing refrigeration house.

Example 7

The present embodiment provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the above-described unit operation control method.

The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on this understanding, the foregoing technical solution may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method described in the respective embodiments or some parts of the embodiments.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The utility model provides a unit operation control method is applied to the refrigeration plant who has the doublestage unit, doublestage unit includes condenser, expansion valve and cooling air unit that communicates in proper order, its characterized in that, doublestage unit still includes: the system comprises a first-stage compressor unit and a second-stage compressor unit which are arranged in series, wherein the air suction end of the first-stage compressor unit is communicated with the outlet end of the cold air unit, the air discharge end of the first-stage compressor unit is communicated with the air suction end of the second-stage compressor unit, and the air suction end of the second-stage compressor unit is also communicated with the outlet end of the cold air unit.

Acquiring the evaporation temperature of the two-stage unit;

controlling the operation states and the operation capacities of the primary compressor unit and the secondary compressor unit according to the evaporation temperature and the freezing point temperature of the storage in the refrigeration equipment;

controlling the operating states and the operating capacities of the primary compressor unit and the secondary compressor unit according to the evaporating temperature and the freezing point temperature of the storage in the refrigeration equipment, comprising:

if the evaporation temperature is smaller than the freezing point temperature of the storage object and is larger than or equal to a preset temperature value, controlling one compressor in the secondary compressor unit to operate according to a first preset capacity, and adjusting the operation capacity of the primary compressor unit according to the evaporation temperature and a target evaporation temperature;

2. The method of claim 1, wherein obtaining an evaporation temperature of the dual-stage unit comprises:

acquiring the evaporation pressure of the two-stage unit;

3. The method of claim 1, wherein adjusting the operating capacity of the primary compressor group based on the evaporating temperature and a target evaporating temperature comprises:

4. The method of claim 1, wherein adjusting the operating capacity of the primary compressor package and the operating capacity of the secondary compressor package based on the evaporating temperature and a target evaporating temperature comprises:

5. The method of claim 4, wherein determining the operating capacity of the secondary compressor unit based on the pressure ratio of the dual-stage unit and the operating capacity of the primary compressor unit comprises:

6. A unit operation control device for a refrigeration apparatus having a two-stage unit comprising a condenser, an expansion valve and a chiller unit in sequential communication, wherein the control device is configured to perform the method of any of claims 1-5, the two-stage unit further comprising: the one-stage compressor unit and the second grade compressor unit that establish ties set up, one-stage compressor unit, its inhale end with the exit end intercommunication of cooling air unit, its exhaust end with the inhale end intercommunication of second grade compressor unit, the inhale end of second grade compressor unit still with the exit end intercommunication of cooling air unit, unit operation controlling means includes:

7. A two-stage unit comprising a condenser, an expansion valve, and a chiller unit in sequential communication, wherein the unit is configured to perform the method of any of claims 1-5, the unit further comprising:

8. The dual stage unit of claim 7, further comprising the unit operation control device of claim 7.

9. The two-stage unit according to claim 7, wherein the one-stage compressor unit comprises at least one compressor, and wherein the two-stage compressor unit comprises at least one compressor, and wherein when the number of compressors of the one-stage compressor unit is more than two, different compressors are arranged in parallel; when the number of compressors in the two-stage compressor unit is more than two, different compressors are connected in parallel.

10. The dual-stage unit of claim 7, further comprising:

and the economizer is arranged between the condenser of the two-stage unit and the cold air unit and is also communicated with the air suction end of the two-stage compressor unit.

11. The dual-stage unit of claim 7, further comprising: the high-pressure electromagnetic valve is arranged between the outlet end of the cold air unit and the air suction end of the secondary compressor unit.

12. A refrigeration device comprising the two-stage unit of any one of claims 7 to 11.

13. A computer readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the method according to any one of claims 1 to 5.