Air conditioner freezing device and control method and readable storage medium

Abstract

The present application relates to air conditioner refrigeration cycle technical field, specifically, it relates to a kind of air conditioner refrigeration device and control method and readable storage medium, the problem solved by the present application: how to adjust high-pressure target value in real time according to the problem of the variation of cycle state to improve the refrigeration performance coefficient of air conditioner, to solve the above problems, the present application provides a kind of air conditioner refrigeration device, refrigeration device includes: intermediate cooler, saturated liquid refrigerant and gaseous refrigerant are stored in intermediate cooler;High side cycle system, intermediate cooler exports gaseous refrigerant to high side cycle system, and gas temperature sensor is arranged at the outlet of high side cycle system;Low side cycle system, intermediate cooler exports saturated liquid refrigerant to low side cycle system, and intermediate temperature sensor is arranged in low side cycle system;Liquid level sensor, liquid level sensor is arranged in intermediate cooler, and liquid level sensor can obtain the liquid level height of saturated liquid refrigerant in intermediate cooler.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioner refrigeration cycle, in particular to an air conditioner freezing device, a control method and a readable storage medium. BACKGROUND

[0002] At present, when the air conditioner performs refrigeration operation, the high pressure target value corresponding to the refrigerant is a fixed value. The high pressure target value is set mainly on the premise that the air conditioner is in stable operation. Regardless of how the cycle state changes, the high pressure target value remains unchanged. However, the air conditioner runs in the same high pressure target value in different use environments, which reduces the refrigeration performance coefficient of the air conditioner. Therefore, how to adjust the high pressure target value in real time according to the cycle state change is one of the problems to be solved by the person skilled in the art. SUMMARY

[0003] The problem solved by the present application is how to adjust the high pressure target value in real time according to the cycle state change to improve the refrigeration performance coefficient of the air conditioner.

[0004] To solve the above problems, the present application provides an operation control method of an air conditioner. The present application provides an air conditioner freezing device. The freezing device comprises: an intermediate cooler, which stores saturated liquid refrigerant and gaseous refrigerant; a high-level side cycle system, which outputs the gaseous refrigerant from the intermediate cooler; a gas temperature sensor arranged at the outlet of the high-level side cycle system; a low-level side cycle system, which outputs the saturated liquid refrigerant from the intermediate cooler; an intermediate temperature sensor arranged in the low-level side cycle system; and a liquid level sensor arranged in the intermediate cooler, which can obtain the liquid level of the saturated liquid refrigerant in the intermediate cooler. The intermediate cooler is connected to the high-level side cycle system and the low-level side cycle system. The high pressure target value of the gaseous refrigerant is determined according to the temperature of the gas temperature sensor and the temperature of the intermediate temperature sensor, and the liquid level corresponding to the high pressure target value.

[0005] Compared with the prior art, the technical effects achieved by adopting the technical scheme are as follows: the arrangement of the high-level side cycle system can pressurize the output gaseous refrigerant; the arrangement of the low-level side cycle system can depressurize the saturated liquid refrigerant; the arrangement of the intermediate temperature sensor can obtain the refrigerant temperature when the saturated liquid refrigerant is output; the arrangement of the gas temperature sensor can obtain the refrigerant temperature of the gaseous refrigerant after passing through the high-level side cycle system; the combination of the values of the intermediate temperature sensor and the gas temperature sensor makes the calculation of the high pressure target value under the current operating state more accurate; and the arrangement of the liquid level sensor can quickly adjust the operating state of the high-level side cycle system and the low-level side cycle system according to the high pressure target value.

[0006] In one embodiment of the present application, the advanced side cycle system specifically comprises: an advanced side compressor, the advanced side compressor being connected with the intermediate cooler; a high-pressure sensor, the high-pressure sensor being arranged at the gas outlet of the advanced side compressor; a gas cooler, the gas cooler being connected with the advanced side compressor, the gaseous refrigerant entering the gas cooler after being pressurized by the advanced side compressor, and a gas temperature sensor being arranged at the gas outlet of the gas cooler.

[0007] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: the arrangement of the advanced side compressor can pressurize the gaseous refrigerant output by the intermediate cooler, the high-pressure value under the current cycle state is obtained by detection, and the high-pressure value becomes more accurate; the arrangement of the gas cooler can exchange heat inside the cycle system with the outside, and ensures stable operation of the refrigeration device; the arrangement of the advanced side expansion valve can convert the gaseous refrigerant into liquid refrigerant and send the liquid refrigerant into the intermediate cooler, and ensures that the intermediate cooler can continuously input liquid refrigerant to the low-level side cycle system.

[0008] In one embodiment of the present application, the refrigeration device further comprises: an advanced side expansion valve, the advanced side expansion valve being arranged between the gas cooler and the intermediate cooler; wherein the advanced side expansion valve is used to depressurize the gaseous refrigerant and deliver the depressurized refrigerant to the intermediate cooler.

[0009] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: the arrangement of the advanced side expansion valve can depressurize the high-pressure gaseous refrigerant, and can cooperate with the liquid level sensor to adjust the volume of the saturated liquid refrigerant entering the intermediate cooler according to the current liquid level height, and improve the stability of the refrigeration device.

[0010] In one embodiment of the present application, the low-level side cycle system specifically comprises: a low-level side expansion valve, the low-level side expansion valve being connected with the liquid outlet of the saturated liquid refrigerant, an intermediate temperature sensor being arranged between the low-level side expansion valve and the intermediate cooler, and the low-level side expansion valve being used to depressurize the saturated liquid refrigerant; an evaporator, the evaporator being connected with the low-level side expansion valve, the evaporator receiving the saturated liquid refrigerant and completing heat exchange with liquid water to convert the saturated liquid refrigerant into gaseous refrigerant; and a low-level side compressor, the low-level side compressor being connected with the evaporator, the low-level side compressor delivering the gaseous refrigerant pressurized to the intermediate cooler.

[0011] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: the arrangement of the low-level side expansion valve can further depressurize the refrigerant in the intermediate cooler, and facilitates heating of the refrigerant by the evaporator; the arrangement of the low-level side compressor can pressurize the refrigerant depressurized by the low-level side expansion valve and send the refrigerant back to the intermediate cooler, and provide the advanced side cycle system with the required gaseous refrigerant, and ensure stable operation of the refrigeration device.

[0012] In one embodiment of the present application, a control method is also provided, which comprises: obtaining the temperature of the gas temperature sensor to obtain a first temperature; obtaining the temperature of the intermediate temperature sensor to obtain an intermediate temperature; determining the high-pressure target value of the refrigeration device according to the intermediate temperature and the first temperature; adjusting the liquid level height of the saturated liquid refrigerant according to the high-pressure target value, and adjusting the operating state of the low-level side circulation system according to the high-pressure target value.

[0013] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: the high-level side circulation system and the low-level side circulation system cooperate with each other to realize the secondary compression of the refrigerant, improve the operation stability of the refrigeration device, the detection of the first temperature and the intermediate temperature can determine the high-pressure target value to which the circulation system needs to be adjusted during operation, improve the coefficient of performance of the air conditioner, and the setting of the saturated liquid refrigerant liquid level height adjustment can ensure that the air conditioner can work stably at the high-pressure target value, thereby improving the stability of the circulation system.

[0014] In one embodiment of the present application, the high-pressure target value of the refrigeration device is determined according to the intermediate temperature and the first temperature, specifically comprising: substituting the intermediate temperature and the first temperature into a high-pressure fitting formula to obtain the high-pressure target value under the current first temperature; the high-pressure fitting formula is: PHop=(0.001367-0.00002968Tm)Tg^2+(0.1852+0.0005230Tm)Tg+0.6628; wherein Tm is the intermediate temperature, Tg is the first temperature, and PHop is the high-pressure target value.

[0015] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: the intermediate temperature and the first temperature are substituted into the high-pressure fitting formula to directly obtain the high-pressure target value, which enables the high-pressure target value under the current circulation state to be quickly determined, and facilitates the low-level side circulation system and the high-level side circulation system to quickly adjust the operating state according to the current high-pressure target value, thereby reducing the time for the total circulation system to enter the optimal operating state.

[0016] In one embodiment of the present application, the liquid level height of the saturated liquid refrigerant is adjusted according to the high-pressure target value, and the operating state of the low-level side circulation system is adjusted, specifically comprising: detecting the liquid level height of the saturated liquid refrigerant inside the intermediate cooler to obtain a current liquid level; when the current liquid level is different from a liquid level target value, adjusting the current liquid level by controlling the opening degree of the high-level side expansion valve, so that the current liquid level reaches the liquid level target value; and when the current liquid level is the same as the liquid level target value, the high-level side expansion valve is controlled to maintain the current opening degree.

[0017] Compared with the prior art, the technical effects reached by adopting the technical scheme are: by comparing the current liquid level with the liquid level target value, the difference between the current cycle state and the optimal cycle state can be intuitively obtained, and the total cycle system can be quickly adjusted.

[0018] In an embodiment of the present application, the adjustment of the liquid level height of the saturated liquid refrigerant according to the high-pressure target value and the adjustment of the operating state of the low-stage cycle system further comprise: the low-stage cycle system is provided with an evaporator, the saturated liquid refrigerant is converted into gaseous refrigerant after passing through the evaporator, a second temperature when the saturated liquid refrigerant enters the evaporator and a third temperature when the gaseous refrigerant is output from the evaporator are obtained; the refrigerant superheat degree is calculated according to the second temperature and the third temperature, and the refrigerant superheat degree is compared with a superheat degree target value to determine whether the opening size of the low-stage expansion valve needs to be adjusted.

[0019] Compared with the prior art, the technical effects reached by adopting the technical scheme are: the second temperature and the third temperature are obtained, so that the temperature difference is more in line with the current working state of the low-stage cycle system, and the calculation of the refrigerant superheat degree is more accurate; the superheat degree target value is set, so that the cycle system can adjust the low-stage expansion valve in time according to the refrigerant superheat degree, and the coefficient of performance can be quickly improved.

[0020] In an embodiment of the present application, the adjustment of the liquid level height of the saturated liquid refrigerant according to the high-pressure target value and the adjustment of the operating state of the low-stage cycle system further comprise: the low-stage cycle system is provided with an evaporator, the saturated liquid refrigerant is converted into gaseous refrigerant after passing through the evaporator, a second temperature when the saturated liquid refrigerant enters the evaporator and a third temperature when the gaseous refrigerant is output from the evaporator are obtained; the refrigerant superheat degree is calculated according to the second temperature and the third temperature, and the refrigerant superheat degree is compared with a superheat degree target value to determine whether the opening size of the low-stage expansion valve needs to be adjusted.

[0021] Compared with the prior art, the technical effects reached by adopting the technical scheme are: the second temperature and the third temperature are obtained, so that the temperature difference is more in line with the current working state of the low-stage cycle system, and the calculation of the refrigerant superheat degree is more accurate; the superheat degree target value is set, so that the cycle system can adjust the low-stage expansion valve in time according to the refrigerant superheat degree, and the coefficient of performance can be quickly improved.

[0022] The present application also provides a readable storage medium, the readable storage medium stores programs or instructions, and the programs or instructions are executed by a processor to realize the steps of the control method in the above embodiment. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of the refrigeration device of the present application is shown in the figure;

[0024] Figure 2 A flow chart of the control method of the refrigeration device of the present application is shown in the figure;

[0025] Figure 3Fig. 1 is a schematic diagram of the relationship between the optimal high pressure line and the first temperature;

[0026] Figure 4 Fig. 2 is a schematic diagram of the optimal coefficient of performance corresponding to different intermediate temperatures and the first temperature;

[0027] Figure 5 Fig. 3 is a schematic diagram of a system of a readable storage medium.

[0028] Legend of reference signs:

[0029] 1, gas cooler; 2, high-stage side expansion valve; 3, intermediate cooler; 4, liquid level sensor; 5, high-stage side compressor; 6, low-stage side expansion valve; 7, inlet temperature sensor; 8, outlet water temperature sensor; 9, outlet temperature sensor; 10, evaporator; 11, low-stage side compressor; 12, intermediate temperature sensor; 13, gas temperature sensor; 120, readable storage medium; 121, processor. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0031] [First embodiment]

[0032] Reference is made to Figure 1 In one specific embodiment, the present application provides a refrigeration device of an air conditioner, the refrigeration device comprising: an intermediate cooler 3, the intermediate cooler 3 storing saturated liquid refrigerant and gaseous refrigerant; a high-stage side circulation system, the intermediate cooler 3 outputting the gaseous refrigerant to the high-stage side circulation system, the high-stage side circulation system being provided with a gas temperature sensor 13 at an outlet thereof; a low-stage side circulation system, the intermediate cooler 3 outputting the saturated liquid refrigerant to the low-stage side circulation system, the low-stage side circulation system being provided with an intermediate temperature sensor 12; and a liquid level sensor 4, the liquid level sensor 4 being arranged at the intermediate cooler 3 and being capable of acquiring the liquid level height of the saturated liquid refrigerant in the intermediate cooler 3; wherein the intermediate cooler 3 is connected to the high-stage side circulation system and the low-stage side circulation system, a high-pressure target value of the gaseous refrigerant is determined according to the temperature of the gas temperature sensor 13 and the temperature of the intermediate temperature sensor 12, and a liquid level height corresponding to the high-pressure target value.

[0033] The gaseous refrigerant is stored at the upper end of the intermediate cooler 3, the saturated liquid refrigerant is stored at the lower end of the intermediate cooler 3, the high-stage side circulation system is connected to the upper end of the intermediate cooler 3, the low-stage side circulation system is connected to the lower end of the intermediate cooler 3, the liquid level is controlled by the liquid level sensor 4, and the gaseous refrigerant is ensured to enter the high-stage side circulation system and the saturated liquid refrigerant is ensured to enter the low-stage side circulation system.

[0034] The gaseous refrigerant enters the high-level side circulation system, and is first lifted from the intermediate pressure to the high pressure, and then exchanges heat with the outside, and then returns to the intermediate cooler 3 after pressure reduction, and then is detected by the high pressure sensor after pressure increase, and exchanges heat with the outside, and then the temperature of the refrigerant after pressure increase is obtained by the gas temperature sensor 13, and the refrigerant after pressure increase is reduced again, and is converted into corresponding saturated liquid refrigerant and gaseous refrigerant according to the working state, and the saturated liquid refrigerant and gaseous refrigerant are transported to the intermediate cooler 3.

[0035] Before the saturated liquid refrigerant enters the low-level side circulation system, the refrigerant temperature of the saturated liquid refrigerant is obtained by the intermediate temperature sensor 12, the saturated liquid refrigerant is converted into gaseous refrigerant by the low-level side circulation system, and is transported to the intermediate cooler 3, the low-level side circulation system and the high-level side circulation system cooperate with each other to form a refrigerant circulation, and realize the continuous working of the refrigeration device.

[0036] According to the refrigerant temperature obtained by the gas temperature sensor 13 and the refrigerant temperature of the saturated liquid refrigerant obtained by the intermediate temperature sensor 12, the target high pressure value at which the refrigeration device can exert the best coefficient of performance is calculated under the current circulation state, and after the corresponding high pressure value is obtained, the running state of the high-level side circulation system and the low-level side circulation system is adjusted according to the target high pressure value.

[0037] The setting of the high-level side circulation system can increase the pressure of the output gaseous refrigerant, the setting of the low-level side circulation system can reduce the pressure of the saturated liquid refrigerant, the setting of the intermediate temperature sensor 12 can obtain the refrigerant temperature when the saturated liquid refrigerant is output, the setting of the gas temperature sensor 13 can obtain the refrigerant temperature of the gaseous refrigerant after passing through the high-level side circulation system, the combination of the values of the intermediate temperature sensor 12 and the gas temperature sensor 13 makes the calculation of the target high pressure value under the current running state more accurate, and the setting of the liquid level sensor 4 can quickly adjust the running state of the high-level side circulation system and the low-level side circulation system according to the target high pressure value.

[0038] Further, the high-level side circulation system specifically comprises: a high-level side compressor 5, the high-level side compressor 5 is connected with the intermediate cooler 3; a high pressure sensor, the high pressure sensor is arranged at the gas outlet of the high-level side compressor 5; a gas cooler 1, the gas cooler 1 is connected with the high-level side compressor 5, the gaseous refrigerant enters the gas cooler 1 after being increased in pressure by the high-level side compressor 5, and the gas temperature sensor 13 is arranged at the gas outlet of the gas cooler 1.

[0039] The high-stage compressor 5 pressurizes the gaseous refrigerant, and outputs the pressurized gaseous refrigerant to the gas cooler 1. The high-stage compressor 5 receives heat delivered to the intermediate cooler 3 by the low-stage cycle system at the same time of receiving the gaseous refrigerant. The gaseous refrigerant is subjected to temperature exchange with the outside in the gas cooler 1, and releases the heat delivered to the intermediate cooler 3 by the low-stage cycle system and the heat generated by the operation of the high-stage compressor 5 to the outside, and reduces the temperature of the refrigerant.

[0040] The operation frequency of the high-stage compressor 5 is adjusted by the high-stage cycle system. When the high-pressure value is not equal to the high-pressure target value, the operation frequency of the high-stage compressor 5 is controlled to make them equal.

[0041] The high-stage compressor 5 pressurizes the gaseous refrigerant output from the intermediate cooler 3. The high-pressure value is made more accurate by detecting the high-pressure value in the current cycle state. The gas cooler 1 exchanges the heat in the cycle system with the outside, and ensures the stable operation of the refrigeration device. The high-stage expansion valve 2 converts the gaseous refrigerant into liquid refrigerant and sends the liquid refrigerant to the intermediate cooler 3, and ensures that the intermediate cooler 3 continuously inputs the liquid refrigerant to the low-stage cycle system.

[0042] Further, the refrigeration device further comprises a high-stage expansion valve 2, which is arranged between the gas cooler 1 and the intermediate cooler 3. The high-stage expansion valve 2 is used to depressurize the gaseous refrigerant and deliver the depressurized refrigerant to the intermediate cooler 3.

[0043] The high-stage expansion valve 2 depressurizes the gaseous refrigerant output from the gas cooler 1, i.e. reduces the refrigerant from high pressure to intermediate pressure. In the depressurization operation, the proportion of the gaseous refrigerant and the saturated liquid refrigerant entering the intermediate cooler 3 can be controlled according to the opening size of the high-stage expansion valve 2, so as to control the liquid level in the intermediate cooler 3.

[0044] The high-stage expansion valve 2 depressurizes the gaseous refrigerant at high pressure, and cooperates with the liquid level sensor 4 to adjust the volume of the saturated liquid refrigerant entering the intermediate cooler 3 according to the current liquid level, so as to improve the stability of the operation of the refrigeration device.

[0045] Further, the low-level side circulation system specifically comprises: a low-level side expansion valve 6, which is connected with the saturated liquid refrigerant outlet, an intermediate temperature sensor 12 is arranged between the low-level side expansion valve 6 and the intermediate cooler 3, and the low-level side expansion valve 6 is used for decompressing the saturated liquid refrigerant; an evaporator 10, which is connected with the low-level side expansion valve 6, receives the saturated liquid refrigerant, exchanges heat with the liquid water, and converts the saturated liquid refrigerant into gaseous refrigerant; and a low-level side compressor 11, which is connected with the evaporator 10, pressurizes the gaseous refrigerant, and delivers the gaseous refrigerant to the intermediate cooler 3.

[0046] After the intermediate cooler 3 outputs the saturated liquid refrigerant, the saturated liquid refrigerant is further decompressed by the low-level side expansion valve 6 and provided to the evaporator 10, and the intermediate temperature sensor 12 is arranged between the liquid outlet of the intermediate cooler 3 and the low-level side expansion valve 6.

[0047] The evaporator 10 absorbs heat from the water, outputs the heated refrigerant to the low-level side compressor 11, the low-level side compressor 11 pressurizes the refrigerant, releases the heat absorbed by the evaporator 10 and the heat generated by the compression work to the intermediate cooler 3, and the intermediate cooler 3 delivers the heat to the gas cooler 1 through the high-level side circulation and exchanges with the outside.

[0048] An inlet temperature sensor 7 is arranged at the refrigerant inlet of the evaporator 10, used for detecting the temperature of the refrigerant entering the evaporator 10, an outlet temperature sensor 9 is arranged at the refrigerant outlet of the evaporator 10, used for detecting the temperature of the refrigerant output, and the opening size of the low-level side expansion valve 6 is set according to the temperature difference between the inlet temperature sensor 7 and the outlet temperature sensor 9.

[0049] An outlet water temperature sensor 8 is arranged at the water outlet of the evaporator 10, used for detecting the outlet water temperature of the evaporator 10, and whether the running state of the evaporator 10 is stable is judged according to the outlet water temperature.

[0050] The arrangement of the low-level side expansion valve 6 can further decompress the refrigerant in the intermediate cooler 3, and the evaporator 10 is convenient for heating the refrigerant, the arrangement of the low-level side compressor 11 can pressurize the refrigerant decompressed by the low-level side expansion valve 6 and send the refrigerant back to the intermediate cooler 3, provide the required gaseous refrigerant for the high-level side circulation system, and ensure the stable running of the refrigeration device.

[0051] Referring to Figures 2 to 4 The application further provides a control method of the refrigeration device of the air conditioner, the refrigeration device described in the above embodiment is applied to the control method, and the control method comprises the following steps.

[0052] S100, acquiring the temperature of the gas temperature sensor to obtain a first temperature, and acquiring the temperature of the intermediate temperature sensor to obtain an intermediate temperature;

[0053] S200, determining the high-pressure target value of the refrigeration device according to the intermediate temperature and the first temperature;

[0054] S300, adjusting the liquid level height of the saturated liquid refrigerant according to the high-pressure target value;

[0055] S400, adjusting the liquid level height of the saturated liquid refrigerant and the operating state of the low-stage side circulation system according to the high-pressure target value.

[0056] In steps S100 to S300, the circuit of the gaseous refrigerant returning to the intermediate cooler after passing through the high-stage side compressor, the gas cooler and the high-stage side expansion valve is referred to as the high-stage side circulation system, the circuit of the saturated liquid refrigerant returning to the intermediate cooler after passing through the low-stage side expansion valve, the evaporator and the low-stage side compressor is referred to as the low-stage side circulation system, the intermediate cooler connects the low-stage side circulation system and the high-stage side circulation system, and the low-stage side circulation system and the high-stage side circulation system constitute the total circulation system of the refrigeration device.

[0057] In step S400, the saturated liquid refrigerant in the intermediate cooler is depressurized by the low-stage side expansion valve to obtain low-pressure refrigerant, and the low-pressure refrigerant is delivered to the evaporator. The evaporator outputs the low-pressure refrigerant into the low-stage side compressor. The low-stage side compressor performs pressure boosting operation on the low-pressure refrigerant, and delivers the refrigerant after the pressure boosting to the intermediate cooler. During the process of the saturated liquid refrigerant passing through the evaporator, temperature sensors are designed at the refrigerant inlet and outlet of the evaporator. The temperature difference value is obtained according to the indication of the temperature sensor, and the opening size of the low-stage side expansion valve is controlled according to the temperature difference value.

[0058] After each intermediate temperature is combined with the corresponding first temperature, the high-pressure target value under the current circulation state can be obtained, the operating state of the high-stage side compressor is adjusted, the refrigerant pressure entering the gas cooler reaches the high-pressure target value, and the opening size of the high-stage side expansion valve is adjusted to change the liquid level height of the saturated liquid refrigerant.

[0059] The high-stage side circulation system and the low-stage side circulation system cooperate with each other to realize the secondary compression of the refrigerant and improve the operation stability of the refrigeration device. The detection of the first temperature and the intermediate temperature can determine the high-pressure target value required by the circulation system during the operation process, improve the coefficient of performance of the air conditioner, and the setting of the saturated liquid refrigerant liquid level height adjustment can ensure that the air conditioner can work stably at the high-pressure target value and improve the stability of the total circulation system.

[0060] Further, the high-pressure target value of the refrigeration device is determined according to the intermediate temperature and the first temperature, specifically including:

[0061] S210, substituting the intermediate temperature and the first temperature into the high-pressure fitting formula to obtain the high-pressure target value under the current first temperature;

[0062] The high pressure fitting formula is:

[0063] PHop= (0.001367-0.00002968Tm)Tg^2+ (0.1852+0.0005230Tm)Tg+0.6628;

[0064] Wherein, Tm is the intermediate temperature, Tg is the first temperature, and PHop is the high pressure target value.

[0065] In step S210, during the process performed by the total circulation system, the control software substitutes the current intermediate temperature and the first temperature into the high pressure fitting formula to determine the high pressure target value that needs to be adjusted, so as to control the working frequency of the high-stage side compressor and the opening size of the high-stage side expansion valve.

[0066] It should be noted that after the high pressure target value under the current intermediate and first temperatures is obtained according to the fitting formula, the optimal high pressure line of the first temperature corresponding to each intermediate temperature can be calculated according to the fitting formula.

[0067] The way of substituting the intermediate temperature and the first temperature into the high pressure fitting formula to directly obtain the high pressure target value enables the high pressure target value under the current circulation state to be quickly determined, which facilitates the low-stage side circulation system and the high-stage side circulation system to quickly adjust the working state according to the current high pressure target value, and reduces the time for the total circulation system to enter the optimal working state.

[0068] Further, adjusting the liquid level height of the saturated liquid refrigerant and adjusting the running state of the low-stage side circulation system according to the high pressure target value, specifically includes:

[0069] S310, detecting the liquid level height of the saturated liquid refrigerant inside the intermediate cooler to obtain a current liquid level;

[0070] S320, when the current liquid level is different from the liquid level target value, adjusting the current liquid level by controlling the opening of the high-stage side expansion valve, so that the current liquid level reaches the liquid level target value;

[0071] S330, when the current liquid level is the same as the liquid level target value, the high-stage side expansion valve is controlled to keep the current opening size.

[0072] In steps S310 to S330, a liquid level sensor is arranged at the intermediate cooler, and the remaining amount of saturated liquid refrigerant in the intermediate cooler can be detected in real time. When the high pressure target value is determined, the cycle requirement corresponding to the high pressure target value is also determined. During the operation of the total circulation system, the current liquid level needs to be kept the same as the liquid level target value. When the current liquid level is lower than the liquid level target value, the opening degree of the high-level side expansion valve needs to be increased to increase the refrigerant flow. When the current liquid level is higher than the liquid level target value, the opening degree of the high-level side expansion valve needs to be reduced to reduce the refrigerant flow.

[0073] By comparing the current liquid level with the liquid level target value, the difference between the current cycle state and the optimal cycle state can be intuitively obtained, so that the total circulation system can be quickly adjusted.

[0074] Further, according to the high pressure target value, the liquid level of the saturated liquid refrigerant is adjusted and the operation state of the low-level side circulation system is adjusted, which further comprises:

[0075] S410, an evaporator is arranged in the low-level side circulation system, and the saturated liquid refrigerant is converted into gaseous refrigerant after passing through the evaporator, and a second temperature when the saturated liquid refrigerant enters the evaporator and a third temperature when the gaseous refrigerant is output from the evaporator are obtained.

[0076] S420, calculating the refrigerant superheat degree according to the second temperature and the third temperature, and comparing the refrigerant superheat degree with a superheat target value to determine whether the opening degree of the low-level side expansion valve needs to be adjusted.

[0077] In steps S410 to S420, the temperature difference is obtained by subtracting the second temperature from the third temperature. According to the temperature difference, the refrigerant superheat degree of the low-level side expansion valve at the current opening degree is calculated. When the refrigerant superheat degree is less than the superheat target value, the opening degree of the low-level side expansion valve needs to be reduced. When the refrigerant superheat degree is greater than the superheat target value, the opening degree of the low-level side expansion valve needs to be increased.

[0078] The second temperature and the third temperature are obtained, so that the temperature difference is more consistent with the current working state of the low-level side circulation system, and the calculation of the refrigerant superheat degree is more accurate. The setting of the superheat target value enables the circulation system to adjust the low-level side expansion valve in time according to the refrigerant superheat degree, so that the coefficient of performance can be quickly improved.

[0079] Further, according to the second temperature and the third temperature, the refrigerant superheat degree is calculated, and the refrigerant superheat degree is compared with the superheat target value to determine whether the opening degree of the low-level side expansion valve needs to be adjusted, which specifically comprises:

[0080] S421, comparing the outlet water temperature with an outlet water target value.

[0081] S422、When the outlet water temperature is not equal to the outlet water target value, the working frequency of the low-stage side compressor is controlled to make the outlet water temperature reach the outlet water target value.

[0082] S423、When the outlet water temperature is equal to the outlet water target value, the working frequency of the low-stage side compressor does not need to be adjusted.

[0083] In steps S421 to S423, the outlet water temperature of the evaporator is used to control the low-stage side expansion valve, so that the operating state of the evaporator is more stable.

[0084] The outlet water temperature of the evaporator is used to control the low-stage side expansion valve, so that the operating state of the evaporator is more stable.

[0085] Further, the existing control method is compared with the control method of the present application, and the existing control method and the control method of the present application are used in the same specification device, and only the high-pressure control method is different.

[0086] The existing control method: the high-pressure target value is a fixed value of 9.0 MPa, which meets the requirement that the value is as low as possible and can realize stable operation under the use condition considered in advance, and the calculation result shows that the refrigeration performance coefficient is 2.70.

[0087] The control method of the present application: the intermediate temperature is 20.2℃, the gas cooler outlet temperature is 37.7℃, the best high pressure is 9.13 MPa, and the value is taken as the high-pressure target value, and the calculation result shows that the refrigeration performance coefficient is 2.82, which is improved by 4% compared with the existing device.

[0088] The control device using the existing control method is referred to as the existing device, and the control device using the control method of the present application is referred to as the device of the present application, and the parameters of the two control devices are shown in the following table:

[0089]

[0090] Referring to Figure 5 The present application also provides a readable storage medium 120, and the readable storage medium 120 stores programs or instructions, and the programs or instructions are executed by the processor 121 to realize the steps of the control method in the above-mentioned embodiments.

[0091] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be subject to the range defined by the claims.

Claims

1. A refrigeration unit for an air conditioner, characterized in that, The refrigeration device includes: Intercooler (3), which stores saturated liquid refrigerant and gaseous refrigerant; Advanced side circulation system, the intercooler (3) outputs the gaseous refrigerant to the advanced side circulation system, the advanced side circulation system is equipped with a gas temperature sensor (13). The low-level side circulation system, wherein the intermediate cooler (3) outputs the saturated liquid coolant to the low-level side circulation system, and the low-level side circulation system is provided with an intermediate temperature sensor (12). A liquid level sensor (4) is provided in the intercooler (3) and the liquid level sensor (4) is able to obtain the liquid level height of the saturated liquid coolant in the intercooler (3); The intermediate cooler (3) is connected to the high-level side circulation system and the low-level side circulation system. The high pressure target value of the gaseous refrigerant and the liquid level height corresponding to the high pressure target value are determined based on the temperature of the gas temperature sensor (13) and the temperature of the intermediate temperature sensor (12).

2. The refrigeration apparatus according to claim 1, characterized in that, The advanced side-circulation system specifically includes: Advanced side compressor (5), which is connected to the intercooler (3); A high-pressure sensor is located at the gas outlet of the advanced side compressor (5); Gas cooler (1), the gas cooler (1) is connected to the advanced side compressor (5), the gaseous refrigerant enters the gas cooler (1) after being pressurized by the advanced side compressor (5), and the gas temperature sensor (13) is located at the gas outlet of the gas cooler (1).

3. The refrigeration apparatus according to claim 2, characterized in that, The refrigeration device further includes: Advanced side expansion valve (2), the advanced side expansion valve (2) is located between the gas cooler (1) and the intercooler (3); The advanced side expansion valve (2) is used to reduce the pressure of the gaseous refrigerant and deliver the reduced refrigerant to the intercooler (3).

4. The refrigeration apparatus according to claim 3, characterized in that, The low-level side circulation system specifically includes: The low-level expansion valve (6) is connected to the outlet of the saturated liquid coolant. The intermediate temperature sensor (12) is located between the low-level expansion valve (6) and the intermediate cooler (3). The low-level expansion valve (6) is used to reduce the pressure of the saturated liquid coolant. Evaporator (10), the evaporator (10) is connected to the low-level expansion valve (6), the evaporator (10) receives the saturated liquid refrigerant and completes heat exchange with liquid water, converting the saturated liquid refrigerant into gaseous refrigerant; The low-level compressor (11) is connected to the evaporator (10) and pressurizes the gaseous refrigerant before delivering it to the intercooler (3).

5. A control method for the refrigeration unit of an air conditioner, characterized in that, The refrigeration apparatus as described in claim 4 is applied to the control method, the control method comprising: The temperature of the gas temperature sensor is obtained to obtain a first temperature; The temperature of the intermediate temperature sensor is obtained to obtain the intermediate temperature; The high-pressure target value of the refrigeration unit is determined based on the intermediate temperature and the first temperature. The liquid level of the saturated liquid coolant and the operating status of the low-level side circulation system are adjusted according to the high-pressure target value.

6. The control method according to claim 5, characterized in that, The step of determining the high-pressure target value of the circulation system based on the intermediate temperature and the first temperature specifically includes: Substituting the intermediate temperature and the first temperature into the high-pressure fitting formula, the high-pressure target value at the current first temperature is obtained; The high-pressure fitting formula is as follows: PHop=(0.001367-0.00002968Tm)Tg^2+(0.1852+0.0005230Tm)Tg+0.6628; Wherein, Tm is the intermediate temperature, Tg is the first temperature, and PHop is the high-pressure target value.

7. The control method according to claim 5, characterized in that, The adjustment of the liquid level of the saturated liquid coolant and the adjustment of the operating status of the low-level side circulation system based on the high-pressure target value specifically include: The current liquid level is obtained by detecting the liquid level of the saturated liquid refrigerant inside the intercooler; When the current liquid level is different from the target liquid level value, the opening of the advanced side expansion valve is controlled to adjust the current liquid level so that the current liquid level reaches the target liquid level value. When the current liquid level is the same as the target liquid level, the advanced side expansion valve is controlled to maintain the current opening size.

8. The control method according to claim 7, characterized in that, The adjustment of the liquid level of the saturated liquid coolant and the adjustment of the operating status of the low-level side circulation system based on the high-pressure target value also includes: The low-level side circulation system is equipped with an evaporator. The saturated liquid refrigerant is converted into the gaseous refrigerant after passing through the evaporator. The second temperature when the saturated liquid refrigerant enters the evaporator and the third temperature when the evaporator outputs the gaseous refrigerant are obtained. The refrigerant superheat is calculated based on the second temperature and the third temperature. The refrigerant superheat is compared with the target superheat value to determine whether the opening of the low-level expansion valve needs to be adjusted.

9. The control method according to claim 8, characterized in that, The step of calculating the refrigerant superheat based on the second temperature and the third temperature, comparing the refrigerant superheat with the target superheat value, and determining whether the opening of the low-stage expansion valve needs adjustment specifically includes: Obtain the outlet water temperature of the evaporator and compare the outlet water temperature with the target outlet water value; Compare the outlet water temperature with the target outlet water value; When the outlet water temperature is not equal to the outlet water target value, the operating frequency of the low-level compressor is controlled to make the outlet water temperature reach the outlet water target value. When the outlet water temperature is equal to the target outlet water value, the operating frequency of the low-level compressor does not need to be adjusted.

10. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions that, when executed by a processor, implement the steps of the control method as described in any one of claims 5 to 9.

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