Refrigerating apparatus of an air conditioner, operation control method, and readable storage medium

Abstract

The present application relates to the field of air conditioner refrigeration, and more particularly to a refrigeration device of an air conditioner, a running control method and a readable storage medium, and solves the problem of how to calculate the liquid level height according to the circulation state without setting a liquid level sensor. To solve the above problem, the present application provides a refrigeration device of an air conditioner, which comprises: an intermediate cooler, the intermediate cooler storing saturated liquid refrigerant and gaseous refrigerant; a high-level side circulation system, the intermediate cooler outputting the gaseous refrigerant to the high-level side circulation system, the high-level side circulation system being provided with a gas temperature sensor; a low-level side circulation system, the intermediate cooler outputting the saturated liquid refrigerant to the low-level side circulation system, the low-level side circulation system being provided with an intermediate temperature sensor; wherein the intermediate cooler is connected to the high-level side circulation system and the low-level side circulation system, and the saturated liquid refrigerant liquid level height is determined according to the temperature of the gas temperature sensor and the temperature of the intermediate temperature sensor.

Description

TECHNICAL FIELD

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

[0002] In the process of adjusting the high-pressure target value in real time according to the cycle state variation, the liquid level height of the saturated liquid refrigerant in the intercooler needs to be obtained in real time, and it is determined whether the air conditioner reaches the optimal cycle state according to the liquid level height. However, the cost of setting a liquid level sensor in the intercooler is too high. Therefore, how to calculate the liquid level height according to the cycle state without setting a liquid level sensor is one of the problems that the person skilled in the art urgently needs to solve. SUMMARY

[0003] The problem solved by the present application is how to calculate the liquid level height according to the cycle state without setting a liquid level sensor.

[0004] To solve the above problems, the embodiment of the present application provides a refrigeration device of an air conditioner, which comprises: an intercooler, the intercooler storing saturated liquid refrigerant and gaseous refrigerant; a high-level cycle system, the intercooler outputting the gaseous refrigerant to the high-level cycle system, and the high-level cycle system being provided with a gas temperature sensor; and a low-level cycle system, the intercooler outputting the saturated liquid refrigerant to the low-level cycle system, and the low-level cycle system being provided with an intermediate temperature sensor; wherein the intercooler is connected to the high-level cycle system and the low-level cycle system, and the liquid level height of the saturated liquid refrigerant is determined according to the temperature of the gas temperature sensor and the temperature of the intermediate temperature sensor.

[0005] Compared with the prior art, the technical effects achieved by adopting the technical scheme are as follows: the setting of the high-level cycle system can increase the pressure of the output gaseous refrigerant, the setting of the low-level cycle system can reduce the pressure of the saturated liquid refrigerant, the setting of the intermediate temperature sensor can obtain the refrigerant temperature when the saturated liquid refrigerant is output, the setting of the gas temperature sensor can obtain the refrigerant temperature of the gaseous refrigerant after passing through the high-level cycle system, and the combination of the values of the intermediate temperature sensor and the gas temperature sensor can directly calculate the liquid level height of the saturated liquid refrigerant in the intercooler, so that the liquid level height of the saturated liquid refrigerant can be accurately obtained without setting a liquid level sensor, thereby reducing the use cost of the refrigeration device.

[0006] In one embodiment of the present application, the high-level side circulation system specifically comprises: a high-level side compressor, which is connected with an intermediate cooler; a high-pressure sensor, which is arranged at the gas outlet of the high-level side compressor; a gas cooler, which is connected with the high-level side compressor, and into which the gaseous refrigerant is fed after being pressurized by the high-level side compressor; and a high-level side expansion valve, which is arranged between the gas cooler and the intermediate cooler.

[0007] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: the arrangement of the high-level side compressor can pressurize the gaseous refrigerant output by the intermediate cooler; the arrangement of the gas cooler can exchange heat between the inside of the circulation system and the outside; the arrangement of the high-level side expansion valve can convert the gaseous refrigerant into liquid refrigerant and feed the liquid refrigerant into the intermediate cooler, so that the intermediate cooler can continuously input liquid refrigerant to the low-level side circulation system.

[0008] In one embodiment of the present application, the low-level side circulation system specifically comprises: a low-level side expansion valve, which is connected with the liquid outlet of the saturated liquid refrigerant, and an intermediate temperature sensor is arranged between the low-level side expansion valve and the intermediate cooler; an evaporator, which is connected with the low-level side expansion valve, and receives the saturated liquid refrigerant to exchange heat with liquid water and convert the saturated liquid refrigerant into gaseous refrigerant; and a low-level side compressor, which is connected with the evaporator, pressurizes the gaseous refrigerant and feeds the gaseous 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 low-level side expansion valve can further depressurize the refrigerant in the intermediate cooler, so that the evaporator can heat the refrigerant; the arrangement of the low-level side compressor can pressurize the refrigerant depressurized by the low-level side expansion valve and feed the refrigerant back to the intermediate cooler, so as to provide the high-level side circulation system with the required gaseous refrigerant and ensure the stable operation of the refrigeration device.

[0010] In one embodiment of the present application, a control method for operating an air conditioner is also provided, and the control method comprises: connecting a low-level side circulation system and a high-level side circulation system through an intermediate cooler to form a total circulation system; determining the liquid level of the saturated liquid refrigerant according to the circulation state of the saturated liquid refrigerant and the gaseous refrigerant in the total circulation system; and determining whether the total circulation system reaches an optimal circulation state according to the liquid level of the saturated liquid refrigerant.

[0011] Compared with the prior art, the technical effects achieved by the technical scheme are that the total circulation system is connected through the intermediate cooler, secondary compression of the refrigerant is realized, the operation stability of the air conditioner is improved, the saturated liquid refrigerant and the gaseous refrigerant are detected separately, and the calculation of the liquid level height in the intermediate cooler is more accurate.

[0012] In an embodiment of the present application, the liquid level height of the saturated liquid refrigerant is determined according to the circulation state of the saturated liquid refrigerant and the gaseous refrigerant in the circulation system, and specifically includes: calculating the outflow gas flow and the outflow liquid flow of the intermediate cooler, denoted as the outflow total amount; calculating the inflow gas flow and the inflow liquid flow of the intermediate cooler, denoted as the inflow total amount; and calculating the liquid level height according to the outflow total amount and the inflow total amount.

[0013] Compared with the prior art, the technical effects achieved by the technical scheme are that the calculation of the outflow total amount and the inflow total amount can intuitively reflect the conversion relationship between the gaseous refrigerant and the saturated liquid refrigerant, and the calculated liquid level height is more accurate.

[0014] In an embodiment of the present application, the outflow gas flow and the outflow liquid flow of the intermediate cooler are calculated, denoted as the outflow total amount, and specifically include: obtaining the saturated gas specific volume and the saturated liquid specific volume corresponding to the intermediate temperature based on a p-h diagram, denoting the saturated gas specific volume as a first specific volume and the saturated liquid specific volume as a second specific volume; obtaining the suction specific volume corresponding to the low-side compressor of the evaporator operating at the evaporation temperature based on the p-h diagram, denoted as a third specific volume; calculating the high-side mass flow according to the first specific volume and a frequency signal corresponding to the high-side compressor, and calculating the low-side mass flow according to the third specific volume and a frequency signal corresponding to the low-side compressor; calculating the outflow liquid flow according to the first specific volume and the low-side mass flow; and calculating the outflow gas flow according to the second specific volume and the high-side mass flow.

[0015] Compared with the prior art, the technical effects achieved by the technical scheme are that the saturated gas specific volume and the saturated liquid specific volume of the refrigerant at different intermediate temperatures can be obtained through the p-h diagram, the data of the first specific volume and the second specific volume are more accurate, the third specific volume is obtained, the refrigerant change amount of the low-side circulation system and the high-side circulation system can be calculated synchronously, the accuracy of calculating the outflow total amount is improved, the high-side mass flow and the low-side mass flow are calculated, the compressor characteristic values of the low-side compressor and the high-side compressor are fully considered, and detection errors caused by different types of compressors are avoided.

[0016] In one embodiment of the present application, the high-level side mass flow is calculated according to the first specific volume and the frequency signal corresponding to the high-level side compressor, and the low-level side mass flow is calculated according to the third specific volume and the frequency signal corresponding to the low-level side compressor, specifically comprising: calculating the low-level side mass flow according to the third specific volume, the theoretical displacement of the low-level side compressor, the characteristic value of the low-level side compressor and the frequency signal of the low-level side compressor; the calculation formula of the low-level side mass flow is: M1= (N1 x η v1 x d v1 ) ÷ V s1 ; wherein M1 is the low-level side mass flow, N1 is the frequency signal of the low-level side compressor, η v1 is the theoretical displacement of the low-level side compressor, d v1 is the characteristic value of the low-level side compressor, and V s1 is the third specific volume; calculating the high-level side mass flow according to the first specific volume, the theoretical displacement of the high-level side compressor, the characteristic value of the high-level side compressor and the frequency signal of the high-level side compressor; the calculation formula of the high-level side mass flow is: M2= (N2 x η v2 x d v2 ) ÷ V gm ; wherein M2 is the high-level side mass flow, N2 is the frequency signal of the high-level side compressor, η v2 is the theoretical displacement of the high-level side compressor, and d v2 is the characteristic value of the high-level side compressor.

[0017] Compared with the prior art, the technical effects achieved by adopting the technical scheme are: the setting of the frequency signal considers the working state of the compressor under the current cycle state, the acquisition of the theoretical displacement and the characteristic value of the compressor, the calculation formula of the low-level side mass flow and the high-level side mass flow corresponds to the equipment in the cycle system, and the accuracy of the low-level side mass flow and the high-level side mass flow values is improved.

[0018] In one embodiment of the present application, the inflow gas flow and the inflow liquid flow of the intermediate cooler are calculated, and are recorded as the total inflow, specifically comprising: acquiring the temperature of the saturated liquid refrigerant output by the low-level side cycle system, recorded as the intermediate temperature, acquiring the refrigerant temperature at the outlet of the gas cooler, obtaining the first temperature, determining the high-level side dryness corresponding to the high-level side cycle system according to the intermediate temperature and the first temperature; calculating the inflow liquid flow according to the high-level side mass flow, the high-level side dryness and the second specific volume; calculating the high-level side gas flow according to the high-level side mass flow, the high-level side dryness and the first specific volume; calculating the low-level side gas flow according to the fourth specific volume of the low-level side compressor based on the p-h diagram, recorded as the fourth specific volume, and the low-level side mass flow and the fourth specific volume; calculating the total inflow according to the low-level side gas flow and the high-level side gas flow.

[0019] Compared with the prior art, the technical effects reached by adopting the technical scheme are: the fourth specific volume is obtained through the working state of the low-stage compressor, the calculation of the total inflow is more in line with the current cycle state, and the accuracy of the liquid level calculation is improved.

[0020] In one embodiment of the present application, the liquid level height is calculated according to the total outflow and the total inflow, specifically comprising: recording the liquid level height as L, and the calculation formula of the liquid level height is: L = [M2 x (1-X h ) - M1] ÷ [M1 x (V d1 -V lm ) + M2 x (1-X h )(V lm -V gm )]; wherein X h is the high-stage dryness, V d1 is the fourth specific volume, and V lm is the second specific volume.

[0021] Compared with the prior art, the technical effects reached by adopting the technical scheme are: the total inflow and the total outflow in the current state are determined through the cycle system, the liquid level change amount is calculated according to the total inflow and the total outflow, the calculated liquid level is more accurate, the liquid level of the intercooler is calculated based on the calculation of the measurement values of multiple low-cost temperature sensors, and the cycle system does not need to be installed with a high-cost liquid level sensor.

[0022] The present application also provides a readable storage medium, and 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 embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a specific structural schematic diagram of the cycle system of the present application;

[0024] Figure 2 is a flowchart of the operation control method of the present application;

[0025] Figure 3 is a system schematic diagram of the readable storage medium.

[0026] MARKED FOR EXPLANATION:

[0027] 1, gas cooler; 2, high-stage compressor; 3, intercooler; 4, high-stage expansion valve; 5, low-stage expansion valve; 6, evaporator; 7, low-stage compressor; 12, intermediate temperature sensor; 13, gas temperature sensor; 120, readable storage medium; 121, processor. DETAILED DESCRIPTION

[0028] In order to make the above objectives, characteristics and advantages of the present application more apparent, concrete embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0029] [First Embodiment]

[0030] Referring to Figure 1 In one specific embodiment, the present application provides a refrigeration device of an air conditioner, which comprises: an intermediate cooler 3, in which saturated liquid refrigerant and gaseous refrigerant are stored; a high-level side circulation system, to which the gaseous refrigerant is outputted from the intermediate cooler 3, and in which a gaseous temperature sensor 13 is arranged; and a low-level side circulation system, to which the saturated liquid refrigerant is outputted from the intermediate cooler 3, and in which an intermediate temperature sensor 12 is arranged; wherein the intermediate cooler 3 is connected to the high-level side circulation system and the low-level side circulation system, and the liquid level of the saturated liquid refrigerant is determined according to the temperature of the gaseous temperature sensor 13 and the temperature of the intermediate temperature sensor 12.

[0031] 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-level side circulation system is connected to the upper end of the intermediate cooler 3, and the low-level side circulation system is connected to the lower end of the intermediate cooler 3, so that the liquid level is controlled by a liquid level sensor to ensure that the gaseous refrigerant enters the high-level side circulation system and the saturated liquid refrigerant enters the low-level side circulation system.

[0032] After the gaseous refrigerant enters the high-level side circulation system, the gaseous refrigerant is first raised to high pressure, then exchanges heat with the outside world, and then returns to the intermediate cooler 3 after being reduced in pressure. After being raised in pressure, the pressure value of the gaseous refrigerant after being raised in pressure is detected by a high-pressure sensor. After exchanging heat with the outside world, the temperature of the refrigerant after being raised in pressure is obtained by the gaseous temperature sensor 13. The refrigerant after being raised in pressure is reduced in pressure 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.

[0033] 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 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, so as to realize the continuous working of the refrigeration device.

[0034] The liquid level of the saturated liquid refrigerant in the intermediate cooler 3 is calculated according to the refrigerant temperature obtained by the gaseous temperature sensor 13 and the refrigerant temperature of the saturated liquid refrigerant obtained by the intermediate temperature sensor 12, and the working state of the high-level side circulation system and the low-level side circulation system is determined according to the liquid level.

[0035] The high-level side circulation system is configured to increase the pressure of the gaseous refrigerant, the low-level side circulation system is configured to decrease the pressure of the saturated liquid refrigerant, the intermediate temperature sensor 12 is configured to obtain the refrigerant temperature when the saturated liquid refrigerant is output, the gaseous temperature sensor 13 is configured to obtain the refrigerant temperature after the gaseous refrigerant passes through the high-level side circulation system, and the value of the intermediate temperature sensor 12 and the value of the gaseous temperature sensor 13 are combined to directly calculate the liquid level of the saturated liquid refrigerant in the intermediate cooler 3, so that the liquid level of the saturated liquid refrigerant can be accurately obtained without a liquid level sensor, and the use cost of the refrigeration device is reduced.

[0036] Further, the high-level side circulation system specifically comprises: a high-level side compressor 2, which is connected with the intermediate cooler 3; a high-pressure sensor, which is arranged at the gaseous outlet of the high-level side compressor 2; a gaseous cooler 1, which is connected with the high-level side compressor 2, and through which the gaseous refrigerant after being increased in pressure by the high-level side compressor 2 enters; and a gaseous temperature sensor 13, which is arranged at the gaseous outlet of the gaseous cooler 1.

[0037] The high-level side compressor 2 increases the pressure of the gaseous refrigerant, and outputs the gaseous refrigerant to the gaseous cooler 1 after the pressure is increased. The high-level side compressor 2 receives the heat delivered to the intermediate cooler 3 by the low-level side circulation system at the same time, and the gaseous refrigerant passes through the high-pressure sensor during the delivery to the gaseous cooler 1 to obtain the temperature of the refrigerant after the pressure is increased. The refrigerant exchanges the temperature with the outside in the gaseous cooler 1, releases the heat absorbed by the low-level side circulation system and the heat generated by the operation of the high-level side compressor 2 to the outside, and reduces the temperature of the refrigerant.

[0038] The working frequency of the high-level side compressor 2 is adjusted by the high-level side circulation system. When the high-pressure value is not equal to the high-pressure target value, the working frequency of the high-level side compressor 2 needs to be controlled to make the two equal.

[0039] The high-level side compressor 2 is configured to increase the pressure of the gaseous refrigerant output by the intermediate cooler 3, the gaseous cooler 1 is configured to exchange the heat in the circulation system with the outside to ensure the stable operation of the refrigeration device, and the high-level side expansion valve 4 is configured to convert the gaseous refrigerant into liquid refrigerant to be sent to the intermediate cooler 3, so that the intermediate cooler 3 can continuously input the liquid refrigerant to the low-level side circulation system.

[0040] Further, the low-level side circulation system specifically comprises: a low-level side expansion valve 5, connected with the saturated liquid refrigerant outlet, an intermediate temperature sensor 12 arranged between the low-level side expansion valve 5 and the intermediate cooler 3, and the low-level side expansion valve 5 used for decompressing the saturated liquid refrigerant; an evaporator 6, connected with the low-level side expansion valve 5, and used for exchanging heat with the liquid water to convert the saturated liquid refrigerant into gaseous refrigerant after receiving the saturated liquid refrigerant; and a low-level side compressor 7, connected with the evaporator 6, and used for delivering the gaseous refrigerant to the intermediate cooler 3 after increasing the pressure of the gaseous refrigerant.

[0041] The intermediate cooler 3 outputs the saturated liquid refrigerant, which is further decompressed by the low-level side expansion valve 5 and provided to the evaporator 6, and the intermediate temperature sensor 12 is arranged between the liquid outlet of the intermediate cooler 3 and the low-level side expansion valve 5.

[0042] The evaporator 6 absorbs heat from the water, and the low-level side compressor 7 releases the heat absorbed by the evaporator 6 and generated by the compression work to the intermediate cooler 3 after increasing the pressure of the refrigerant, and the intermediate cooler 3 delivers the heat to the gas cooler 1 through the high-level side circulation system and exchanges with the outside.

[0043] An inlet temperature sensor is arranged at the refrigerant inlet of the evaporator 6, used for detecting the temperature of the refrigerant entering the evaporator 6, and an outlet temperature sensor is arranged at the refrigerant outlet of the evaporator 6, used for detecting the temperature of the refrigerant output, and the opening size of the low-level side expansion valve 5 is set according to the temperature difference between the inlet temperature sensor and the outlet temperature sensor.

[0044] An outlet water temperature sensor is arranged at the water outlet of the evaporator 6, used for detecting the outlet water temperature of the evaporator 6, and the running state of the evaporator 6 is judged according to the outlet water temperature.

[0045] The low-level side expansion valve 5 can further decompress the refrigerant in the intermediate cooler 3, and the low-level side compressor 7 can increase the pressure of the refrigerant decompressed by the low-level side expansion valve 5 and send it back to the intermediate cooler 3, so as to provide the required gaseous refrigerant for the high-level side circulation system and ensure the stable operation of the refrigeration device.

[0046] Referring to Figure 2 In one specific embodiment, the present application provides a running control method of an air conditioner, and the control method comprises:

[0047] S100, the low-level side circulation system and the high-level side circulation system are connected through the intermediate cooler and form a total circulation system;

[0048] S200, determining the liquid level height of the saturated liquid refrigerant according to the circulation state of the saturated liquid refrigerant and the gaseous refrigerant in the total circulation system;

[0049] S300, judging whether the total circulation system reaches the optimal circulation state according to the liquid level height of the saturated liquid refrigerant.

[0050] In step S100, the intermediate cooler is used to connect the low-level side circulation system and the high-level side circulation system, when the refrigerant enters the high-level side circulation system, the pressure is first increased and then decreased and returned to the intermediate cooler, when the refrigerant enters the low-level side circulation system, the pressure is first decreased and then increased and returned to the intermediate cooler, the low-level side circulation system releases heat to the intermediate cooler, the heat absorption of the intermediate cooler and the working heat of the high-level side compressor are sent to the gaseous cooler together, and the high-level side circulation system and the low-level side circulation system cooperate with each other, so that the air conditioner can stably operate.

[0051] In step S200, the output of the saturated liquid refrigerant and the input of the gaseous refrigerant are calculated from the low-level side circulation system, the output of the gaseous refrigerant, the input of the gaseous refrigerant and the input of the liquid refrigerant are calculated from the high-level side circulation system, and the liquid level height under the current circulation state is calculated.

[0052] In step S300, there is a corresponding liquid level target value in each circulation state, when the current liquid level is different from the liquid level target value, the circulation system does not reach the optimal circulation state, and when the current liquid level is the same as the liquid level target value, the total circulation system reaches the optimal circulation state.

[0053] The total circulation system is connected through the intermediate cooler, realizes the secondary compression of the refrigerant, improves the operation stability of the air conditioner, and detects the saturated liquid refrigerant and the gaseous refrigerant separately, so that the calculation of the liquid level height in the intermediate cooler is more accurate.

[0054] Further, the liquid level height of the saturated liquid refrigerant is determined according to the circulation state of the saturated liquid refrigerant and the gaseous refrigerant in the total circulation system, and specifically includes:

[0055] S210, calculating the outflow gas flow and the outflow liquid flow of the intermediate cooler, and recording as the outflow total amount;

[0056] S220, calculating the inflow gas flow and the inflow liquid flow of the intermediate cooler, and recording as the inflow total amount;

[0057] S230, calculating the liquid level height according to the outflow total amount and the inflow total amount.

[0058] In step S210, the outflow total amount can be divided into the outflow of the gaseous refrigerant in the intermediate cooler to the high-level side circulation system and the outflow of the saturated liquid refrigerant in the intermediate cooler to the low-level side circulation system.

[0059] In step S220, the total inflow amount can be divided into gaseous refrigerant flowing into the intermediate cooler through the high-stage side expansion valve and saturated liquid refrigerant flowing into the intermediate cooler, and gaseous refrigerant flowing into the intermediate cooler through the low-stage side compressor.

[0060] In step S230, the initial liquid level height in the intermediate cooler can be directly obtained, and the current liquid level height can be calculated according to the total outflow amount and the total inflow amount in the circulation process.

[0061] The calculation of the total outflow amount and the total inflow amount can directly reflect the conversion relationship between the gaseous refrigerant and the saturated liquid refrigerant, so that the calculated liquid level height is more accurate.

[0062] Further, the outflow gas flow and the outflow liquid flow of the intermediate cooler are calculated, which are recorded as the total outflow amount, and specifically include:

[0063] S211, obtaining the saturated gas specific volume and the saturated liquid specific volume corresponding to the intermediate temperature based on the p-h diagram, recording the saturated gas specific volume as the first specific volume and the saturated liquid specific volume as the second specific volume;

[0064] S212, obtaining the suction gas specific volume corresponding to the low-stage side compressor when the evaporator operates at the evaporation temperature based on the p-h diagram, recording the suction gas specific volume as the third specific volume;

[0065] S213, calculating the high-stage side mass flow according to the first specific volume and the frequency signal corresponding to the high-stage side compressor, and calculating the low-stage side mass flow according to the third specific volume and the frequency signal corresponding to the low-stage side compressor;

[0066] S214, calculating the outflow liquid flow according to the first specific volume and the low-stage side mass flow, and calculating the outflow gas flow according to the second specific volume and the high-stage side mass flow.

[0067] In step S211, the part of the gas cooler connected with the high-stage side circulation system stores gaseous refrigerant, and the part of the gas cooler connected with the low-stage side circulation system stores saturated liquid refrigerant. The gaseous refrigerant enters the high-stage side circulation system, is pressurized, and then enters the gas cooler. The saturated liquid refrigerant enters the low-stage side circulation system. A temperature sensor is arranged at the outlet of the saturated liquid refrigerant for detecting the intermediate temperature.

[0068] After the intermediate temperature is obtained, the first specific volume and the second specific volume corresponding to the high-stage side circulation system can be obtained based on the p-h diagram.

[0069] In step S212, the third specific volume is obtained by taking the evaporation temperature and the suction gas temperature of the low-stage side compressor as reference indexes in the low-stage side circulation system and combining the p-h diagram.

[0070] In step S213, different working frequencies of the high-level side compressor correspond to different refrigerant flow rates, so the compressor corresponding compressor characteristic values need to be considered in the calculation of the high-level side mass flow rate, and similarly, different working frequencies of the low-level side compressor correspond to different refrigerant flow rates, so the compressor corresponding compressor characteristic values need to be considered in the calculation of the low-level side mass flow rate.

[0071] The flow rate of the volume of the gas refrigerant flowing out of the intermediate cooler to the high-level side circulation system is set as F gho [m 3 / s], the flow rate of the volume of the saturated liquid refrigerant flowing out of the intermediate cooler to the low-level side circulation system is set as F llo [m 3 / s], V gm is the first specific volume, V lm is the second specific volume, F gho and F llo are specific calculation formulas as follows:

[0072] F gho = M2 x V gm ;

[0073] F llo = M1 x V lm .

[0074] The saturated gas specific volume and the saturated liquid specific volume of the refrigerant at different intermediate temperatures can be obtained through the p-h diagram, the data of the first specific volume and the second specific volume are more accurate, the third specific volume is obtained, the refrigerant change amount of the low-level side circulation system and the high-level side circulation system can be calculated synchronously, the accuracy of the calculation of the total outflow is improved, the calculation of the high-level side mass flow rate and the low-level side mass flow rate fully considers the compressor characteristic values of the low-level side compressor and the high-level side compressor, and detection errors caused by different types of compressors are avoided.

[0075] Further, the high-level side mass flow rate is calculated according to the first specific volume and the frequency signal corresponding to the high-level side compressor, and the low-level side mass flow rate is calculated according to the third specific volume and the frequency signal corresponding to the low-level side compressor, and specifically includes:

[0076] The low-level side mass flow rate is calculated according to the third specific volume, the theoretical displacement of the low-level side compressor, the characteristic value of the low-level side compressor and the frequency signal of the low-level side compressor;

[0077] The calculation formula of the low-level side mass flow rate is:

[0078] M1= (N1 x η v1 x d v1 ) ÷ V s1 ;

[0079] Wherein, M1 is the low side mass flow, N1 is the frequency signal of the low side compressor, η v1 is the theoretical displacement of the low side compressor, d v1 is the characteristic value of the low side compressor, V s1 is the third specific volume;

[0080] The high side mass flow is calculated according to the first specific volume, the theoretical displacement of the high side compressor, the characteristic value of the high side compressor and the frequency signal of the high side compressor;

[0081] The calculation formula of the high side mass flow is:

[0082] M2= (N2 x η v2 x d v2 ) ÷ V gm ;

[0083] Wherein, M2 is the high side mass flow, N2 is the frequency signal of the high side compressor, η v2 is the theoretical displacement of the high side compressor, d v2 is the characteristic value of the high side compressor.

[0084] In steps S213a to S213b, the characteristic parameters of the low side compressor are combined with the third specific volume to obtain a calculation formula that meets the equipment parameters in the low side circulation system, and the characteristic parameters of the high side compressor are combined with the first specific volume to obtain a calculation formula that meets the equipment parameters in the high side circulation system.

[0085] The setting of the frequency signal takes into account the working state of the compressor under the current circulation state, and the theoretical displacement and the compressor characteristic value are obtained, so that the calculation formula of the low side mass flow and the high side mass flow corresponds to the equipment in the circulation system, and the accuracy of the low side mass flow and the high side mass flow value is improved.

[0086] Further, the inflow gas flow and the inflow liquid flow of the intermediate cooler are calculated, which are recorded as the total inflow, which specifically includes:

[0087] S221, obtaining the temperature of the saturated liquid refrigerant output by the low side circulation system, recorded as the intermediate temperature, obtaining the refrigerant temperature at the outlet of the gas cooler 1, obtaining the first temperature, determining the high side dryness corresponding to the high side circulation system according to the intermediate temperature and the first temperature;

[0088] S222, calculating the inflow liquid flow according to the high side mass flow, the high side dryness and the second specific volume, and calculating the high side gas flow according to the high side mass flow, the high side dryness and the first specific volume;

[0089] S223, the fourth specific volume is obtained based on the p-h diagram, the low-stage gas flow rate is calculated based on the low-stage mass flow rate and the fourth specific volume, and the inflow total is calculated based on the low-stage gas flow rate and the high-stage gas flow rate.

[0090] In step S221, a temperature sensor is provided at the outlet of the saturated liquid refrigerant of the intercooler to detect the intermediate temperature, and after the first temperature and the intermediate temperature are obtained, the high-stage dryness is obtained based on the p-h diagram.

[0091] In step S223, temperature sensors are provided at the inlet and the outlet of the evaporator 6, the evaporation temperature is obtained based on the measurement value of the temperature sensor at the inlet, the suction temperature of the low-stage compressor is obtained based on the measurement value of the temperature sensor at the outlet, and the fourth specific volume is obtained based on the p-h diagram based on the suction temperature and the evaporation temperature.

[0092] The volume flow rate of the gas refrigerant of the high-stage cycle system flowing into the intercooler is set as F ghi [m 3 / s], the volume flow rate of the gas refrigerant of the low-stage cycle system flowing into the intercooler is set as F gli [m 3 / s], the volume flow rate of the saturated liquid refrigerant of the high-stage cycle system flowing into the intercooler is set as F lhi [m 3 / s], the high-stage dryness is denoted as X h , the second specific volume is denoted as V lm , the fourth specific volume is denoted as V d1 , F ghi , F gli , and F lhi are calculated as follows:

[0093] F ghi =M2×X h ×V gm ;

[0094] F gli =M1×V d1 ;

[0095] F lhi =M2×(1-X h )×V lm .

[0096] The fourth specific volume is obtained based on the working state of the low-stage compressor 7, the calculation of the inflow total is more in line with the current cycle state, and the accuracy of the liquid level calculation is improved.

[0097] Further, the liquid level height is calculated based on the outflow total and the inflow total, and specifically includes:

[0098] S231, record the liquid level height as L, the calculation formula of the liquid level height is:

[0099] L=[M2x(1-X h )-M1] / [M1x(V d1 -V lm )+M2x(1-X h )(V lm -V gm )].

[0100] Wherein, X h is the advanced side dryness, V d1 is the fourth specific volume, and V lm is the second specific volume.

[0101] In step S231, the liquid level height is calculated according to the total outflow and the total inflow.

[0102] L=(F lhi -F llo ) / (F ghi +F gli -F gho +F lhi -F llo ), the corresponding calculation formula of F gho , F llo , F ghi , F gli and F lhi is substituted to obtain L=[M2x(1-X h )-M1] / [M1x(V d1 -V lm )+M2x(1-X h )(V lm -V gm )].

[0103] The total inflow and the total outflow in the current state are determined through the circulation system, the liquid level change amount is calculated according to the total inflow and the total outflow, the calculated liquid level is more accurate, the intermediate cooler liquid level is calculated based on the measurement values of multiple low-cost temperature sensors, and the circulation system does not need to be installed with a high-cost liquid level sensor.

[0104] Referring to Figure 3 , the application further provides a readable storage medium 120, 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 embodiment.

[0105] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A freezing apparatus of an air conditioner, characterized by comprising: The refrigeration device comprises: An intermediate cooler (3) in which saturated liquid refrigerant and gaseous refrigerant are stored; A high-level side circulation system to which the gaseous refrigerant is output by the intermediate cooler (3), and in which a gas temperature sensor (13) is arranged; A low-level side circulation system to which the saturated liquid refrigerant is output by the intermediate cooler (3), and in which an intermediate temperature sensor (12) is arranged; The intermediate cooler (3) is connected to the high-level side circulation system and the low-level side circulation system, and the liquid level of the saturated liquid refrigerant is determined according to the temperature of the gas temperature sensor (13) and the temperature of the intermediate temperature sensor (12).

2. The freezing apparatus according to claim 1, wherein The high-level side circulation system specifically comprises: A high-level side compressor (2) connected to the intermediate cooler (3); A high-pressure sensor arranged at a gas outlet of the high-level side compressor (2); A gas cooler (1) connected to the high-level side compressor (2), the gaseous refrigerant enters the gas cooler (1) after being pressurized by the high-level side compressor (2), and the gas temperature sensor (13) is arranged at a gas outlet of the gas cooler (1); A high-level side expansion valve (4) arranged between the gas cooler (1) and the intermediate cooler (3).

3. The refrigeration device of claim 2, wherein The low-level side circulation system specifically comprises: A low-level side expansion valve (5) connected to a liquid outlet of the saturated liquid refrigerant, the intermediate temperature sensor (12) is arranged between the low-level side expansion valve (5) and the intermediate cooler (3), and the low-level side expansion valve (5) is used for depressurizing the saturated liquid refrigerant; An evaporator (6) connected to the low-level side expansion valve (5), which exchanges heat with liquid water after receiving the saturated liquid refrigerant, and converts the saturated liquid refrigerant into gaseous refrigerant; A low-level side compressor (7) connected to the evaporator (6), which pressurizes the gaseous refrigerant and delivers it to the intermediate cooler (3).

4. An operation control method of an air conditioner, characterized by, The control method is applied to the refrigeration device of claim 3, and the control method comprises: The low-level side circulation system and the high-level side circulation system are connected by the intermediate cooler and form a total circulation system; The liquid level of the saturated liquid refrigerant is determined according to the circulation state of the saturated liquid refrigerant and the gaseous refrigerant in the total circulation system; Whether the total circulation system reaches an optimal circulation state is determined according to the liquid level of the saturated liquid refrigerant.

5. The control method according to claim 4, characterized by, The liquid level of the saturated liquid refrigerant is determined according to the circulation state of the saturated liquid refrigerant and the gaseous refrigerant in the total circulation system, specifically comprising: The outflow gas flow and the outflow liquid flow of the intermediate cooler are calculated, which are recorded as the total outflow; The inflow gas flow and the inflow liquid flow of the intermediate cooler are calculated, which are recorded as the total inflow; The liquid level height is calculated according to the outflow total amount and the inflow total amount.

6. The control method according to claim 5, characterized by The outflow gas flow and the outflow liquid flow of the intermediate cooler are calculated, and the outflow total amount is recorded. The saturated gas specific volume corresponding to the intermediate temperature and the saturated liquid specific volume are obtained based on the p-h diagram, the saturated gas specific volume is recorded as a first specific volume, and the saturated liquid specific volume is recorded as a second specific volume; The suction gas specific volume corresponding to the low-stage side compressor when the evaporator operates at the evaporation temperature is obtained based on the p-h diagram, and recorded as a third specific volume; The high-stage side mass flow is calculated according to the first specific volume and the frequency signal corresponding to the high-stage side compressor, and the low-stage side mass flow is calculated according to the third specific volume and the frequency signal corresponding to the low-stage side compressor; The outflow liquid flow is calculated according to the first specific volume and the low-stage side mass flow; The outflow gas flow is calculated according to the second specific volume and the high-stage side mass flow.

7. The control method according to claim 6, characterized by, The high-stage side mass flow is calculated according to the first specific volume and the frequency signal corresponding to the high-stage side compressor, and the low-stage side mass flow is calculated according to the third specific volume and the frequency signal corresponding to the low-stage side compressor, and specifically includes: The low-stage side mass flow is calculated according to the third specific volume, the theoretical displacement of the low-stage side compressor, the characteristic value of the low-stage side compressor, and the frequency signal of the low-stage side compressor; The calculation formula of the low-stage side mass flow is: M1 = (N1 x η v1 × d v1 ) ÷ V s1 ; wherein M1 is the low-stage mass flow, N1 is the frequency signal of the low-stage compressor, η v1 is the theoretical displacement of the low-stage compressor, d v1 is the characteristic value of the low-stage compressor, V s1 is the third specific volume; The high-stage side mass flow is calculated according to the first specific volume, the theoretical displacement of the high-stage side compressor, the characteristic value of the high-stage side compressor, and the frequency signal of the high-stage side compressor; The calculation formula of the high-stage side mass flow is: M2 = (N2 x η v2 × d v2 ) ÷ V gm ; where M2 is the high-stage side mass flow, N2 is the frequency signal of the high-stage side compressor, η v2 is the theoretical displacement of the high-stage side compressor, d v2 is the characteristic value of the high-stage side compressor, V gm is the first specific volume.

8. The control method according to claim 6, characterized by, The inflow gas flow and the inflow liquid flow of the intermediate cooler are calculated, and the inflow total amount is recorded. The temperature of the saturated liquid refrigerant output by the low-stage side circulation system is obtained, recorded as an intermediate temperature, the refrigerant temperature at the outlet of the gas cooler is obtained, recorded as a first temperature, and the high-stage side dryness corresponding to the high-stage side circulation system is determined according to the intermediate temperature and the first temperature; The inflow liquid flow is calculated according to the high-stage side mass flow, the high-stage side dryness, and the second specific volume; The high-stage side gas flow is calculated according to the high-stage side mass flow, the high-stage side dryness, and the first specific volume; The discharge gas specific volume of the low-stage side compressor is obtained based on the p-h diagram, recorded as a fourth specific volume, and the low-stage side gas flow is calculated according to the low-stage side mass flow and the fourth specific volume; The inflow total amount is calculated according to the low-stage side gas flow and the high-stage side gas flow.

9. The control method according to claim 8, characterized by, The liquid level height is calculated according to the outflow total amount and the inflow total amount, and specifically includes: The liquid level height is recorded as L, and the calculation formula of the liquid level height is: L = [M2 x (1 - X h ) - M1] ÷ [M1 x (V d1 - V lm ) + M2 x (1 - X h ) (V lm - V gm )] ; wherein X h is the high side dryness, V d1 is the fourth specific volume, V lm is the second specific volume.

10. A readable storage medium, characterized by, The program or instruction is stored on the readable storage medium, and the program or instruction is executed by the processor to realize the steps of the control method in any one of claims 4 to 9.

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