阅读说明：本技术 一种制冷系统制冷剂状态的判定方法 (Method for judging state of refrigerant of refrigerating system ) 是由 李越峰 赵静 于 2021-01-21 设计创作，主要内容包括：本发明涉及制冷控制领域,公开了一种制冷系统制冷剂状态的判定方法,通过系统状态自动检测方式实现对制冷系统状态进行准确判断。包括：S1.获取制冷系统在正常制冷剂充注状态下压缩机的名义状态参数与室外温度、压缩机运行频率的关系表；S2.在制冷系统运行过程中实时获取其实际状态参数,所述实际状态参数包括室外温度tor、压缩机运行频率f、压缩机的运行功率pw、压缩机绕组温度tcr和排气温度tp,并计算出tcr和tp的实际差值△t；S3.根据步骤S2获取的室外温度和压缩机运行频率,从步骤S1获取的关系表中找到对应的名义状态参数pw0、△t0；通过分析△t与△t0的数值关系,pw与pw0的数值关系,得出制冷剂状态。本发明适用于空调。(The invention relates to the field of refrigeration control, and discloses a method for judging the state of a refrigerant of a refrigeration system. The method comprises the following steps: s1, obtaining a relation table of nominal state parameters of a compressor of a refrigeration system under a normal refrigerant charging state, outdoor temperature and compressor operation frequency; s2, acquiring actual state parameters of the refrigerating system in real time in the operation process of the refrigerating system, wherein the actual state parameters comprise an outdoor temperature tor, a compressor operation frequency f, an operation power pw of the compressor, a compressor winding temperature tcr and an exhaust temperature tp, and calculating an actual difference value delta t of the tcr and the tp; s3, according to the outdoor temperature and the compressor running frequency obtained in the step S2, finding corresponding nominal state parameters pw0 and delta t0 from the relation table obtained in the step S1; the refrigerant state is obtained by analyzing the numerical relationship between Δ t and Δ t0, and the numerical relationship between pw and pw 0. The invention is suitable for air conditioners.)

1. A method of determining a refrigerant state of a refrigeration system, comprising the steps of:

s1, obtaining a relation table of nominal state parameters of a compressor of a refrigeration system in a normal refrigerant charging state, outdoor temperature and compressor operation frequency, wherein the nominal state parameters of the compressor comprise nominal operation power pw0 of the compressor and nominal temperature difference delta t0 of the temperature of a compressor winding and exhaust temperature;

s2, acquiring actual state parameters of the refrigerating system in real time in the operation process of the refrigerating system, wherein the actual state parameters comprise an outdoor temperature tor, a compressor operation frequency f, an operation power pw of the compressor, a compressor winding temperature tcr and an exhaust temperature tp, and calculating an actual difference value delta t of the tcr and the tp;

s3, according to the outdoor temperature and the compressor running frequency obtained in the step S2, finding corresponding nominal state parameters pw0 and delta t0 from the relation table obtained in the step S1;

s4, analyzing the numerical relation between delta t and delta t0 and the numerical relation between pw and pw0 to obtain the state of the refrigerant.

2. A method for determining a refrigerant status of a refrigeration system as set forth in claim 1, wherein the step S1 obtains the relationship table by downloading from a network or reading from a local memory.

3. A method for determining a refrigerant condition of a refrigeration system as set forth in claim 1, wherein the actual condition parameter obtained in step S2 is an average value over a period of time.

4. A method for determining a refrigerant state of a refrigeration system as set forth in claim 1 or 2, wherein step S4 specifically includes:

s41, calculating a ratio kt of delta t and delta t0 and a ratio kp of pw and pw 0;

s42, judging whether kt is larger than or equal to a judgment constant kt0, if so, entering a step S43, and otherwise, entering a step S44;

s43, comparing the relation between kp and kpl and kpu, wherein kpu and kpl are preset upper and lower limits, kpu is more than 1, and kpl is less than 1; when kp is larger than or equal to kpu, judging that air is mixed in the refrigerant; when kp is less than or equal to kpl, judging that the refrigerant is insufficient;

and S44, judging whether kt is less than or equal to kt0-wc, wherein wc is a refrigerant filling error under the condition that the refrigeration system works normally, if yes, judging that the refrigerant is excessive when kp is more than or equal to kpu, and otherwise, returning to the step S2.

5. A method for determining a refrigerant condition of a refrigeration system as set forth in claim 4, wherein after step S43, the method further includes the steps of;

the compressor is operated to a predetermined frequency, the refrigerant state is again judged in accordance with steps S2-S4, and the result of the previous judgment is verified based on the result of the judgment again.

6. The method for determining a refrigerant state of a refrigeration system according to claim 4, wherein if the tcr obtained in step S2 is greater than the winding temperature limit high temperature tcrh, it is determined that air is seriously mixed in the refrigerant.

Technical Field

The invention relates to the field of refrigeration control, in particular to a method for judging the state of a refrigerant of a refrigeration system.

Background

The refrigerant is also called as a refrigeration working medium and is a working medium of refrigeration cycle, and the cycle corresponds to a specific refrigerant working medium under specific pressure. The vapor compression type refrigeration system compresses a low-pressure refrigerant through a compressor to form high-temperature high-pressure gas, discharges the high-temperature high-pressure gas into a condenser, dissipates heat through heat exchange with the surrounding environment in the condenser to form high-temperature high-pressure refrigerant liquid, expands the high-temperature high-pressure refrigerant liquid through a throttling device to form low-pressure refrigerant, enters an evaporator in a two-phase state, exchanges heat with the surrounding environment through the evaporator to form low-temperature low-pressure refrigerant gas, and then enters the compressor. The whole refrigeration cycle is repeated in this way, and a refrigeration function is formed.

The change of the refrigerant charge of the air conditioning system has great influence on the air conditioning performance, and each air conditioner needs to have an optimal refrigerant charge when being designed. However, the problems of refrigerant shortage, excessive charging and air mixing in the refrigeration system can be caused by various reasons in the production and installation processes of the air conditioner.

The refrigeration cycle is generally a totally-enclosed system, and needs to be vacuumized before injecting the refrigerant, so that the higher the purity of the refrigerant in the whole refrigeration system is, the better the effect is. The ambient air at present mainly comprises nitrogen, oxygen and the like, the temperature of the liquefaction points of the nitrogen and the oxygen exceeds minus 180 ℃, and a common refrigerant can be liquefied at normal temperature, so that if air is mixed in a conventional refrigeration system, the air always exists in a gas state in the refrigeration cycle process, the capacity of liquefaction, expansion and temperature reduction cannot be formed, and the gas forms a large obstruction to a throttling device, so that the refrigeration cycle is difficult to flow.

In production, installation and after-sales service of the refrigeration system, air mixing possibility exists, and the influence of a small amount of mixed air on a refrigeration cycle is small and generally cannot be perceived. If more air is mixed into the air conditioning system, the circulation flow of the refrigeration system is not smooth, the refrigeration effect is poor, the heat dissipation of a motor of the compressor is poor, and the final high-temperature failure of the lubricating oil of the compressor can be caused in severe cases.

The refrigerant is mixed into a small amount of air to deteriorate the capacity of the refrigerating system, and the more the refrigerant is mixed, the worse the refrigerating effect is. In the production process of the air conditioner, the quick connectors are adopted for connection, the tools are worn, the wearing condition of each tool is different, and air is mixed due to poor sealing. Similarly, in the installation process, if the evacuation is forgotten, or the evacuation effect of the vacuum pump is poor, or even the pipeline connection does not form a closed loop, air is mixed.

Air mixed in a refrigeration system is a pain point in the refrigeration industry, and how to identify the pain point is an industrial technical difficulty.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method for judging the state of the refrigerant of the refrigeration system is provided, and the state of the refrigeration system is accurately judged in an automatic detection mode of the state of the system.

In order to solve the above problems, the present invention provides a method for determining a refrigerant state of a refrigeration system, comprising the steps of:

s1, obtaining a relation table of nominal state parameters of a compressor of a refrigeration system in a normal refrigerant charging state, outdoor temperature and compressor operation frequency, wherein the nominal state parameters of the compressor comprise nominal operation power pw0 of the compressor and nominal temperature difference delta t0 of the temperature of a compressor winding and exhaust temperature;

s2, acquiring actual state parameters of the refrigerating system in real time in the operation process of the refrigerating system, wherein the actual state parameters comprise an outdoor temperature tor, a compressor operation frequency f, an operation power pw of the compressor, a compressor winding temperature tcr and an exhaust temperature tp, and calculating an actual difference value delta t of the tcr and the tp;

s3, according to the outdoor temperature and the compressor running frequency obtained in the step S2, finding corresponding nominal state parameters pw0 and delta t0 from the relation table obtained in the step S1;

s4, analyzing the numerical relation between delta t and delta t0 and the numerical relation between pw and pw0 to obtain the state of the refrigerant.

In the present invention, the relationship table required to be obtained in step S1 is generally established by an experiment when the air conditioner manufacturer designs the air conditioner, and after the relationship table is established, the manufacturer may select to place the relationship table in the network server, so that the refrigeration system is downloaded from the network when operating in a networked manner, or the relationship table may be directly written into the body memory of the refrigeration system, so that the refrigeration system can read from the local memory.

Further, in order to improve the accuracy, the actual state parameter acquired in step S2 is preferably an average value over a period of time.

Further, step S4 may specifically include:

s41, calculating a ratio kt of delta t and delta t0 and a ratio kp of pw and pw 0;

s42, judging whether kt is larger than or equal to a judgment constant kt0, if so, entering a step S43, and otherwise, entering a step S44;

s43, comparing the relation between kp and kpl and Kpu, wherein Kpu and kpl are preset upper and lower limits, Kpu is more than 1, and kpl is less than 1; when kp is larger than or equal to kpu, judging that air is mixed in the refrigerant; when kp is less than or equal to kpl, judging that the refrigerant is insufficient;

and S44, judging whether kt is less than or equal to kt0-wc, wherein wc is a refrigerant filling error under the condition that the refrigeration system works normally, if yes, judging that the refrigerant is excessive when kp is more than or equal to kpu, and otherwise, returning to the step S2.

Further, after step S43, the following steps are also included;

the compressor is operated to a predetermined frequency, the refrigerant state is again judged in accordance with steps S2-S4, and the result of the previous judgment is verified based on the result of the judgment again.

Further, if tcr acquired in step S2 is greater than the winding temperature limit high temperature tcrh, it is determined that air is seriously mixed into the refrigerant.

The invention has the beneficial effects that: according to the method for judging the state of the refrigerant of the refrigeration system, disclosed by the invention, self-checking judgment of various states such as air mixing of the refrigerant, insufficient refrigerant, excessive refrigerant and the like can be realized through an automatic detection mode of the state of the system. When the refrigeration system is subjected to factory inspection, the refrigerant state can be automatically detected through the invention, and abnormal machines can be found in time; the invention can also automatically detect when the user uses the air conditioner, for example, the conditions of refrigerant air mixing, refrigerant insufficiency, refrigerant excess and the like are found, and the prompt is carried out through the user interaction interface, so that the working of the air conditioner in the abnormal state of the refrigerant is reduced; in the air conditioner maintenance process, can get into refrigerant state detection procedure through remote controller, cell-phone APP, maintenance frock, automated inspection improves maintenance efficiency.

Drawings

FIG. 1 is a flow chart of the present invention.

Fig. 2 is a flow chart of self-checking of the state of the refrigerant during the operation of the air conditioner.

Detailed Description

Aiming at the situation that the state of the refrigerant cannot be automatically detected through system state parameters in the refrigeration field at present, the invention provides a method for judging the state of the refrigerant of a refrigeration system, which specifically comprises the following steps as shown in figure 1:

s1, obtaining a relation table of nominal state parameters of a compressor of a refrigeration system in a normal refrigerant charging state, outdoor temperature and compressor operation frequency, wherein the nominal state parameters of the compressor comprise nominal operation power pw0 of the compressor and nominal temperature difference delta t0 of the temperature of a compressor winding and exhaust temperature, and the form of the relation table can be shown in table 1;

TABLE 1 relationship of nominal state parameters of compressor with outdoor temperature and compressor operating frequency

frequency/Hz	Outdoor ambient temperature/. degree.C	Nominal operating power/W	Nominal winding temperature-exhaust/° c
				f1	tor1	pw01	△t01
f2	tor2	pw02	△t02
				f3	tor3	pw03	△t03

In the present invention, the relationship table required to be obtained in step S1 is generally established by an experiment when the air conditioner manufacturer designs the air conditioner, and after the relationship table is established, the manufacturer may select to place the relationship table in the network server, so that the refrigeration system is downloaded from the network when operating in a networked manner, or the relationship table may be directly written into the body memory of the refrigeration system, so that the refrigeration system can read from the local memory.

S2, acquiring actual state parameters of the refrigerating system in real time in the operation process of the refrigerating system, wherein the actual state parameters comprise an outdoor temperature tor, a compressor operation frequency f, an operation power pw of the compressor, a compressor winding temperature tcr and an exhaust temperature tp, and calculating an actual difference value delta t of the tcr and the tp; at the moment, if the tcr is greater than the winding temperature limit high-temperature tcrh, the compressor should be immediately closed, and the phenomenon is defined as information output display of the refrigeration system seriously mixed with air;

in the step, the method for accurately acquiring the temperature of the compressor winding can refer to Chinese patent with the patent publication number of CN109883566A and the name of the method is a motor winding temperature detection method based on magnetic flux; for improved accuracy, the obtained outdoor temperature tor, the operating power pw of the compressor, the compressor winding temperature tcr and the discharge temperature tp are preferably averaged over a period of time.

S3, according to the outdoor temperature and the compressor running frequency obtained in the step S2, corresponding nominal state parameters pw0 and Δ t0 are found from the relation table obtained in the step S1.

And S4, analyzing the numerical relationship between delta t and delta t0 and the numerical relationship between pw and pw0 to obtain whether the refrigerant is mixed with air, insufficient refrigerant or excessive refrigerant, and performing pushing display through an air conditioner display panel, a mobile phone app and a maintenance detection device. The specific steps of obtaining the refrigerant state in this step may include:

s41, calculating a ratio kt of delta t and delta t0 and a ratio kp of pw and pw 0;

s42, judging whether kt is larger than or equal to a judgment constant kt0, if so, entering a step S43, and otherwise, entering a step S44;

s43, comparing the relation between kp and kpl and Kpu, wherein Kpu and kpl are preset upper and lower limits, Kpu is more than 1, and kpl is less than 1; when kp is more than or equal to kpu; when kp is less than or equal to kpl, judging that the refrigerant is insufficient, such as lack of fluorine;

in order to verify the result of the determination, after the step S43 is finished, the compressor may be continuously operated to the designated frequency, the operating power pw ' of the compressor and the nominal operating power pw0 ' of the compressor at the designated frequency are obtained again according to the steps S2 and S3, the ratio kp ' of pw ' and pw0 ' is calculated, the refrigerant state determination is performed again according to the refrigerant state determination method of the step S43, and the verification of the result of the previous determination is completed according to the result of the re-determination.

S44, judging whether kt is less than or equal to kt0-wc, wherein wc is a refrigerant filling error under the condition that the refrigeration system works normally, if yes, judging that the refrigerant is excessive when kp is more than or equal to kpu, and otherwise, returning to the step S2.

The invention is further illustrated by the following examples.

Example 1

Embodiment 1 provides a refrigerant state self-checking method of an air conditioner during operation, as shown in fig. 2, including the following steps:

s1, obtaining a relation table of nominal state parameters of a compressor of an air conditioner in a normal refrigerant charging state, outdoor temperature and compressor operation frequency, wherein the relation table is obtained by downloading from a network or reading from a local memory, and the nominal state parameters of the compressor comprise nominal operation power pw0 of the compressor and nominal temperature difference delta t0 of the temperature of a compressor winding and exhaust temperature;

s2, acquiring actual state parameters of the air conditioner in real time in the running process of the air conditioner, wherein the actual state parameters comprise an outdoor temperature tor, a compressor running frequency f, running power pw of the compressor, a compressor winding temperature tcr and an exhaust temperature tp, and calculating an actual difference delta t of the tcr and the tp, namely delta t is tcr-tp; at the moment, if the tcr is greater than the winding temperature limit high-temperature tcrh, the compressor is immediately closed, and the phenomenon is defined as the information output display of the air which is seriously mixed into the air of the air conditioner;

s3, according to the outdoor temperature and the compressor running frequency obtained in the step S2, corresponding nominal state parameters pw0 and Δ t0 are found from the relation table obtained in the step S1.

And S4, obtaining the state of the refrigerant by analyzing the numerical relationship between delta t and delta t0 and the numerical relationship between pw and pw0, and performing push display through an air conditioner display panel and a mobile phone app. In this step, the specific step of obtaining the state of the refrigerant includes:

s41, calculating a ratio kt of delta t and delta t0 and a ratio kp of pw and pw0, namely kt ═ delta t/. DELTA.t 0 and kp ═ pw/pw 0;

s42, judging whether kt is larger than or equal to a judgment constant kt0, if so, entering a step S43, and otherwise, entering a step S44;

s43, comparing the relation between kp and kpl and Kpu, wherein Kpu and kpl are preset upper and lower limits, Kpu is more than 1, and kpl is less than 1; when kp is larger than or equal to kpu, judging that air is mixed in the refrigerant; when kp is less than or equal to kpl, judging that the refrigerant is insufficient; then, in order to verify the result of the previous judgment, the compressor is continuously operated to the designated frequency, the refrigerant state judgment is performed again according to the steps S2-S4, and the result of the previous judgment is verified according to the result of the judgment again;

and S44, judging whether kt is less than or equal to kt0-wc, wherein wc is the refrigerant filling error in normal operation of the air conditioner, if yes, judging that the refrigerant is excessive when kp is more than or equal to kpu, and otherwise, returning to the step S2.

Example 2

Embodiment 2 provides a refrigerant state self-checking method when an air conditioner is started, which includes the following steps:

s1, when a system is started, obtaining a relation table of nominal state parameters of a compressor, outdoor temperature and compressor operation frequency of the air conditioner in a normal refrigerant charging state, wherein the nominal state parameters of the compressor comprise nominal operation power pw0 of the compressor and nominal temperature difference delta t0 of the temperature of a compressor winding and exhaust temperature;

in order to avoid that the air conditioner cannot be networked in time after the air conditioner is moved (for example, the air conditioner is moved from the address a of the user to the address B of the user), and further cannot download the relationship table, the embodiment preferably reads the relationship table from the local memory.

S2, starting refrigeration of the system, detecting actual state parameters of the system in real time, wherein the actual state parameters comprise an outdoor temperature tor, a compressor running frequency f, running power pw of the compressor, a compressor winding temperature tcr and an exhaust temperature tp, and calculating an actual difference delta t of the tcr and the tp;

if the winding temperature of the compressor rapidly rises to exceed tcrh in a short time, immediately closing the compressor, and defining the phenomenon as information output display of air which is seriously mixed into the air conditioner; if the tcr is less than or equal to the winding temperature limit high temperature tcrh, then the step S3 is executed;

s3, according to the outdoor temperature and the compressor running frequency obtained in the step S2, finding corresponding nominal state parameters pw0 and Δ t0 from the relation table obtained in the step S1, and calculating a ratio kt of the Δ t and the Δ t0 and a ratio kp of the pw and the pw0, namely kt ═ Δ t/. DELTA.t 0, and kp ═ pw/pw 0;

s4, judging whether kt is larger than or equal to a judgment constant kt0 of kt, if so, entering a step S6, and otherwise, entering a step S5;

s5, judging whether kt is less than or equal to kt0-wc, wherein wc is the refrigerant filling error in normal operation of the air conditioner, if yes, judging that the refrigerant is excessive when kp is more than or equal to kpu, and if not, returning to the step S2

S6, comparing the relation between kp and kpl and kpu, wherein kpu and kpl are preset upper and lower limits, kpu is more than 1, and kpl is less than 1; when kp is larger than or equal to kpu, primarily judging that air is mixed in the refrigerant; when kp is less than or equal to kpl, preliminarily judging that the refrigerant is insufficient;

s7, the result of the preliminary determination in step S6 is a result after the air conditioner is started, and the result may not be accurate enough due to the fact that the air conditioner is just started, so this embodiment may further continue to reduce the compressor operation to the specified frequency f ', and after the compressor operation to the specified frequency for a period of time t, obtain an average actual state parameter value within the time t, including an outdoor temperature tor ', an operation power pw ' of the compressor, a compressor winding temperature tcr ' and an exhaust temperature tp ', and calculate an actual difference Δ t ' between tor ' and tp ', that is, Δ t ' ═ tcr ' -tp '; then, according to the outdoor temperature tor 'and the compressor running frequency f', finding out corresponding nominal state parameters pw0 and Δ t0 from the relation table acquired in the step S1;

s8, analyzing the numerical relation between delta t 'and delta t0, and the numerical relation between pw' and pw0 to obtain the refrigerant state: calculating the ratio kt of the Δ t 'and the Δ t0 and the ratio kp of the pw' and the pw0, i.e. kt ═ Δ t '/. DELTA t0, kp ═ pw'/pw 0; comparing the relationship of kp with kpl and kpu, wherein kpu and kpl are preset upper and lower limits, kpu > 1 and kpl < 1; when kp is larger than or equal to kpu, judging that air is mixed in the refrigerant for the second time; when kp is less than or equal to kpl, judging that the refrigerant is insufficient for the second time;

s9, when the second judgment result of the step S8 is consistent with the primary judgment result of the step S6, the state of the refrigerant can be finally determined; if the second determination result of step S8 does not match the preliminary determination result of step S6, the second determination result of step S8 is usually the final result.