Method for judging cold loss of refrigerant on line and air conditioning system

Abstract

The invention provides a method for online judging the cold loss of a refrigerant. The method is characterized by comprising the following steps: S01, acquiring data; s02, the refrigerant flow of a condenser, the refrigerant flow of an evaporator and the refrigerant flow from the condenser to the evaporator are determined according to the data; s03, the size relation of the determined refrigerant flow of the condenser, the determined refrigerant flow of the evaporator and the determined refrigerant flow from the condenser to the evaporator is judged; s04, if the refrigerant flow of the condenser is larger than the refrigerant flow from the condenser to the evaporator, it is judged that refrigerant cold loss happens to the condenser; and if the refrigerant flow from the condenser to the evaporator is larger than the refrigerant flow of the evaporator, it is judged that refrigerant cold loss happens to the evaporator. Whether the refrigerant cold loss occurs in the air conditioning system or not can be judged online through real-time monitoring and calculation, and whether the part where the cold loss occurs is the evaporator or the condenser can be accurately judged.

Description

Technical Field

[0001] The present application relates to a method for online determination of refrigerant cold loss and an air conditioning system, and in particular to a method for online determination of the cause and location of refrigerant cold loss in an air conditioning system and an air conditioning system using the method.

[0002] Background

[0003] When the lithium bromide absorption unit is operating normally, when the unit is running at high load or the evaporator refrigerant circulation volume is too large, the refrigerant (for example, pure water or water mixed with a small amount of lithium bromide solution) may enter the absorber from the evaporator in liquid form, or may enter the generator from the condenser. Summary of the invention

[0004] After careful observation by the inventors, it was found that the refrigerant directly enters the absorber and generator without evaporating through the evaporator and is mixed into the lithium bromide solution, which will consume additional heat source of the generator; when the heat source is constant, the concentration and temperature of the solution at the generator outlet decrease, thereby reducing the absorption effect of the concentrated solution entering the absorber and the evaporation efficiency of the evaporator, which will lead to a decrease in the cooling capacity and performance of the unit.

[0005] It is necessary to find a method that can determine the cause and location of refrigerant cold loss without stopping the machine, and there is no need to sample the inlet and outlet solutions of the generator to avoid unit leakage. Therefore, according to the first aspect of the present application, a method for online determination of refrigerant cold loss is provided, which is characterized by comprising the following steps:

[0006] S01, obtain data;

[0007] S02, determining the refrigerant flow rate of the condenser, the refrigerant flow rate of the evaporator, and the refrigerant flow rate from the condenser to the evaporator according to the data;

[0008] S03, determining the relationship between the determined refrigerant flow rate of the condenser, the refrigerant flow rate of the evaporator, and the refrigerant flow rate from the condenser to the evaporator;

[0009] S04: If the refrigerant flow rate of the condenser is greater than the refrigerant flow rate from the condenser to the evaporator, it is determined that the condenser has a refrigerant loss; if the refrigerant flow rate from the condenser to the evaporator is greater than the refrigerant flow rate of the evaporator, it is determined that the evaporator has a refrigerant loss.

[0010] According to a first aspect of the present application, it is characterized in that: in step S04, if the refrigerant flow from the condenser to the evaporator is greater than the refrigerant flow of the evaporator, step S04 further includes:

[0011] Step S04-1, if the evaporator refrigerant level is higher than the evaporator overflow level and the condenser refrigerant level is not higher than the condenser overflow level, open the overflow valve;

[0012] Step S04-2, if the overflow valve is opened so that the refrigerant level in the evaporator is not higher than the overflow level of the evaporator, and the refrigerant flow from the condenser to the evaporator is not greater than the refrigerant flow of the evaporator, it is determined that the cause of the refrigerant loss in the evaporator is due to refrigerant overflow.

[0013] According to the first aspect of the present application, it is characterized in that: step S04-2 further includes, if opening the overflow valve cannot lower the evaporator refrigerant level to the evaporator overflow level, and makes the condenser refrigerant level higher than the condenser overflow level, and at this time the refrigerant flow from the condenser to the evaporator is greater than the refrigerant flow of the evaporator, it is judged that the refrigerant is overfilled.

[0014] According to the first aspect of the present application, it is characterized in that: in step S04-2, the overflow valve is closed before determining the cause of refrigerant loss in the evaporator or determining that the refrigerant is overfilled.

[0015] According to the first aspect of the present application, it is characterized in that: step S04-2 further includes, if the overflow valve is opened so that the evaporator refrigerant level is not higher than the evaporator overflow level, and at this time the refrigerant flow from the condenser to the evaporator is greater than the refrigerant flow of the evaporator, reducing the opening of the evaporator self-circulation valve.

[0016] According to the first aspect of the present application, it is characterized in that: step S04 further includes:

[0017] Step S04-3, determine whether the refrigerant flow from the condenser to the evaporator is greater than the refrigerant flow of the evaporator. If the refrigerant flow from the condenser to the evaporator is not greater than the refrigerant flow of the evaporator, determine that the cause of the refrigerant loss in the evaporator is that the refrigerant vapor carries the refrigerant liquid into the absorber.

[0018] According to the first aspect of the present application, it is characterized in that: step S04-3 further includes: if the refrigerant flow from the condenser to the evaporator is greater than the refrigerant flow of the evaporator, it is prompted that the cause of the refrigerant loss in the evaporator needs to be further confirmed.

[0019] According to the first aspect of the present application, it is characterized in that: the acquired data includes unit detection data and unit setting data, wherein the unit detection data includes cold water inlet temperature, cold water outlet temperature, condenser cooling water inlet temperature, condenser cooling water outlet temperature, evaporator refrigerant temperature, condenser refrigerant temperature and generator solution outlet temperature; wherein the unit setting data includes cold water inlet water temperature design value, cold water outlet water temperature design value, unit cooling capacity design value, cooling water inlet water temperature design value, cooling water outlet water temperature design value, unit heat dissipation design value.

[0020] According to the first aspect of the present application, it is characterized in that: the evaporator refrigerant vapor enthalpy value can be determined according to the evaporator refrigerant temperature; the condenser refrigerant enthalpy value can be determined according to the condenser refrigerant temperature; the condenser refrigerant vapor enthalpy value can be determined according to the generator solution outlet temperature and the condenser refrigerant temperature; the unit cooling capacity can be determined according to the cold water inlet temperature, the cold water outlet temperature, the cold water inlet water temperature design value, the cold water outlet water temperature design value and the unit cooling capacity design value; and the condenser heat exchange capacity can be determined according to the condenser cooling water inlet temperature, the condenser cooling water outlet temperature, the cooling water inlet water temperature design value, the cooling water outlet water temperature design value and the unit heat dissipation design value.

[0021] According to the first aspect of the present application, it is characterized in that: the refrigerant flow rate of the evaporator can be determined according to the refrigeration capacity of the unit, the evaporator refrigerant vapor enthalpy value and the condenser refrigerant enthalpy value; and the refrigerant flow rate of the condenser can be determined according to the condenser heat exchange capacity, the condenser refrigerant enthalpy value and the condenser refrigerant vapor enthalpy value.

[0022] According to the first aspect of the present application, it is characterized in that: the unit detection data also includes the refrigerant flow from the condenser to the evaporator; or the refrigerant flow from the condenser to the evaporator can be determined by the evaporator refrigerant temperature and the condenser refrigerant temperature.

[0023] According to the first aspect of the present application, it is characterized in that: the unit detection data also includes measuring the evaporator internal pressure and the condenser internal pressure, the evaporator refrigerant temperature can be determined according to the evaporator internal pressure, and the condenser refrigerant temperature can be determined according to the condenser internal pressure.

[0024] According to the second aspect of the present application, an air-conditioning system is provided, including an evaporator, an absorber, a generator, a condenser and a control device, wherein the evaporator is connected to the condenser through a pipeline, and the absorber is connected to the generator through a pipeline, and is characterized in that: the cause and location of the refrigerant cold loss are determined according to the method for online determination of the refrigerant cold loss described in the first aspect of the present application.

[0025] According to a second aspect of the present application, it is characterized in that an overflow pipeline is provided between the evaporator and the condenser. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] These and other features and advantages of the present application may be better understood by reading the following detailed description with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout, wherein:

[0027] Figure 1 A schematic block diagram of components of an air conditioning system having an absorption lithium bromide unit;

[0028] Figure 2A A component block diagram of a first embodiment of an air conditioning system of the present application;

[0029] Figure 2B It is the enthalpy curve of the refrigerant vapor in the evaporator;

[0030] Figure 2C It is the enthalpy curve of the refrigerant vapor in the condenser;

[0031] Figure 2D is a graph of the temperature and pressure of the refrigerant water;

[0032] Figure 3 It is a schematic diagram of the refrigerant vapor entering the absorber from the evaporator;

[0033] Figure 4A The first part of the control flow chart for online judgment of refrigerant cooling loss;

[0034] Figure 4B The second part of the control flow chart for online judgment of refrigerant cooling loss;

[0035] Figure 5 A component block diagram of a second embodiment of an air conditioning system of the present application;

[0036] Figure 6 A block diagram showing the specific details of the control device. DETAILED DESCRIPTION

[0037] The purpose of the present invention is to provide a method and system for detecting and diagnosing faults of an air-conditioning unit, so as to timely capture and accurately locate the faults and causes of the air-conditioning unit, thereby solving a series of problems caused by conventional troubleshooting, such as untimely response, long time span, high maintenance cost, and wide impact range.

[0038] Figure 1 The figure is a schematic block diagram of the components of an air conditioning system having an absorption lithium bromide unit.

[0039] like Figure 1As shown, the air conditioning system 100 with an absorption lithium bromide unit includes an evaporator 110, an absorber 120, a generator 130 and a condenser 140, wherein the generator 130 is provided with a heat source fluid inlet 182 (the fluid here is a heat source, such as high-temperature steam or hot water), a heat source fluid outlet 184 (the fluid here can be condensed water of high-temperature steam or a fluid with a lower temperature than the fluid inlet), a generator solution inlet 186, a generator solution outlet 187 and a generator refrigerant vapor outlet 188; the evaporator 110 is provided with a refrigerant water inlet 176, an evaporator refrigerant vapor outlet 178, a cold water inlet 172 and a cold water outlet 174; the absorber 120 is provided with a cooling water inlet 162, an absorber solution inlet 164, an absorber solution outlet 166; the condenser 140 is provided with a refrigerant water outlet 152 and a cooling water outlet 156. A first pipeline 171 is provided between the generator solution outlet 187 and the absorber solution inlet 164, and a first solution pump 170 is provided on the first pipeline 171 for transporting the concentrated solution in the generator 130 to the absorber 120. A second pipeline 173 is provided between the absorber solution outlet 166 and the generator solution inlet 186, and a second solution pump 160 is provided on the second pipeline 173 for transporting the dilute solution in the absorber 120 to the generator 130. A heat exchanger 163 is provided between the first pipeline 171 and the second pipeline 173 for promoting heat exchange between the concentrated solution in the first pipeline 171 and the dilute solution in the second pipeline 173. A third pipeline 175 is provided between the refrigerant water outlet 152 and the refrigerant water inlet 176, and a throttling device 153 is provided on the third pipeline 175 for throttling and reducing the pressure of the refrigerant water flowing out of the condenser 140. The evaporator 110 is also provided with a self-circulating pipeline 177, which can transfer the refrigerant at the lower part of the evaporator 110 to the refrigerant liquid distribution device 304 above the evaporator 110 (see Figure 3 ) is used to keep the evaporator tube group always covered with refrigerant. A refrigerant pump 161 is provided on the self-circulating pipeline 177 to promote the circulation of refrigerant water inside the evaporator 110.

[0040] The air conditioning system 100 includes a solution circulation route and a refrigerant circulation route.

[0041] The solution circulation route is as follows: the concentrated solution entering the absorber 120 absorbs the refrigerant vapor from the evaporator 110 to become a dilute solution, and the dilute solution flows into the generator 130 after passing through the second solution pump 160. The dilute solution flowing into the generator 130 is heated by the high-temperature steam and concentrated into a concentrated solution, and the concentrated solution is transported to the absorber 120 by the first solution pump 170 to absorb the refrigerant vapor from the evaporator 110, completing the solution circulation.

[0042] The refrigerant circulation route is as follows: the refrigerant vapor generated by the generator 130 enters the condenser 140 and is condensed in the condenser 140. The refrigerant water from the condenser 140 enters the evaporator 110 through the throttling device 153, absorbs heat on the outer wall of the heat exchange tube of the evaporator 110 and evaporates into refrigerant vapor. The refrigerant vapor enters the absorber 120 and is absorbed by the concentrated solution. The solution after absorbing the refrigerant vapor enters the generator 130 through the second solution pump 160 and is heated to generate refrigerant vapor, completing the refrigerant circulation.

[0043] The air conditioning system 100 further includes an evaporator self-circulation route.

[0044] The refrigerant water is pumped from the bottom of the evaporator 110 to the top of the evaporator 110 by the refrigerant pump 161 , thereby accelerating the heat cycle of the refrigerant inside the evaporator 110 .

[0045] The connection between the air conditioning system 100 and the outside includes a heat source route, a cooling water route, and a cold water route.

[0046] The heat source route is: the heat source entering the generator 130 from the heat source fluid inlet 182 heats and concentrates the dilute solution inside the generator, and the heat source releases heat and flows out of the generator 130 from the heat source fluid outlet 184 .

[0047] The cooling water route is as follows: the cooling water entering the absorber 120 from the cooling water inlet 162 cools the solution in the absorber 120 , and the cooling water continues to flow to the condenser 140 , and after cooling the refrigerant vapor in the condenser 140 , flows out from the cooling water outlet 156 of the condenser 140 .

[0048] The cold water route is as follows: the cold water entering the evaporator 110 from the cold water inlet 172 is evaporated by the refrigerant water in the evaporator 110 and absorbs heat, and then the cold water is cooled and flows out of the evaporator 110 from the cold water outlet 174 .

[0049] Figure 2A A component block diagram of a first embodiment of an air conditioning system of the present application; Figure 2B-2D A function curve graph involved in the first embodiment is shown.

[0050] like Figure 2A As shown, the air conditioning system 200 of the present application is Figure 1An overflow pipe 201 is added to the absorption lithium bromide unit shown in the figure. The overflow pipe 201 is connected between the outlet of the evaporator refrigerant pump 161 and the bottom of the condenser 140 to overflow the refrigerant in the evaporator 110 into the condenser 140. On this basis, a water inlet temperature sensor 202 is set near the cold water inlet 172 to measure the cold water inlet temperature; a water outlet temperature sensor 204 is set near the cold water outlet 174 to measure the cold water outlet temperature; a cooling water inlet sensor 208 is set near the condenser inlet of the cooling water to measure the condenser cooling water inlet temperature; a cooling water outlet sensor 209 is set near the condenser outlet of the cooling water to measure the condenser cooling water outlet temperature; an evaporator refrigerant temperature sensor 212 is set near the outlet of the refrigerant pump 161 or the evaporator 110 to measure the evaporator refrigerant temperature; a condenser refrigerant temperature sensor 214 is set near the condenser 140 to measure the condenser refrigerant temperature; a refrigerant flow sensor 216 is set on the connecting pipeline between the condenser 140 and the evaporator 110 (i.e., the third pipeline 175) to measure the condenser refrigerant temperature. The invention relates to a method for measuring the refrigerant flow from the condenser 140 to the evaporator 110; a solution temperature sensor 218 is provided on the outlet solution pipeline of the generator 130 (i.e., the first pipeline 171) to measure the solution temperature near the generator solution outlet 187; a self-circulation valve 232 is provided on the pipeline between the refrigerant pump 161 and the top of the evaporator (i.e., the self-circulation pipeline 177) (when the unit is working, the self-circulation valve 232 is usually kept in an open state); an overflow valve 234 is provided on the overflow pipeline 201; an evaporator liquid level monitoring device 222 (liquid level sensor or liquid level switch) is added at the overflow height of the evaporator 110 to determine whether the refrigerant liquid level of the evaporator is higher than the overflow liquid level; a condenser liquid level monitoring device 224 (liquid level sensor or liquid level switch) is added at the overflow height of the condenser 140 to determine whether the refrigerant liquid level of the condenser is higher than the overflow liquid level.

[0051] In addition, the air conditioning system 200 of the present application is Figure 1 A control device 206 is added to the absorption lithium bromide unit shown in the figure. The control device 206 can be communicatively connected with all the sensors and all the valves mentioned above, and is used to receive the feedback signals of each sensor, and can control the opening and closing or the opening degree of each valve according to the feedback signals. The control device 206 also has a user interaction interface (not shown in the figure), which can receive information input by the user and can also feedback messages to the user, such as alarm messages, leakage messages, etc.

[0052] During the stable operation of the air conditioning system 200, the evaporator load (i.e., the unit cooling capacity Q) can be calculated by measuring the cold water inlet temperature and the cold water outlet temperature respectively by the water inlet temperature sensor 202 and the water outlet temperature sensor 204. e ), the calculation formula is as follows:

[0053]

[0054] Wherein, TCHWi represents the measured value of the cold water inlet temperature, TCHWo represents the measured value of the cold water outlet temperature, TCHWid represents the design value of the cold water inlet temperature (set in the program according to the unit design, for example, set to 12.0°C), TCHWod represents the design value of the cold water outlet temperature (set in the program according to the unit design, for example, set to 7.0°C), Q ed Indicates the design value of the unit's cooling capacity, which is related to different unit operating conditions (for example, set to 500USRT).

[0055] The condenser load (i.e., the condenser heat exchange capacity Q) can be calculated by measuring the condenser cooling water inlet temperature and the condenser cooling water outlet temperature respectively by the cooling water inlet sensor 208 and the cooling water outlet sensor 209. c ), the calculation formula is as follows:

[0056]

[0057] Wherein, TCWci represents the measured value of the condenser cooling water inlet temperature, TCWco represents the measured value of the condenser cooling water outlet temperature, TCWid represents the design value of the cooling water inlet temperature (set in the program according to the unit design, for example, set to 32.0°C), TCCod represents the design value of the cooling water outlet temperature (set in the program according to the unit design, for example, set to 38.0°C), Q acd It indicates the design value of the unit heat dissipation, which is related to different unit operating conditions (for example, it is set to 1166.7USRT).

[0058] The evaporator refrigerant temperature sensor 212 and the condenser refrigerant temperature sensor 214 can measure the evaporator refrigerant temperature and the condenser refrigerant temperature respectively, and then Figure 2B The function curve shown in (evaporator refrigerant vapor enthalpy curve) calculates the evaporator refrigerant vapor enthalpy H1' and the refrigerant enthalpy H3 returned from the condenser to the evaporator. Figure 2B The horizontal axis represents the refrigerant temperature in the evaporator, and the vertical axis represents the refrigerant enthalpy value of the evaporator.

[0059] The refrigerant flow rate (G Re ), the calculation formula is as follows:

[0060]

[0061] Among them, Q e Indicates the cooling capacity of the unit calculated above.

[0062] The condenser refrigerant temperature can be measured by the condenser refrigerant temperature sensor 214 and the solution temperature near the generator solution outlet 187 can be measured by the sensor 218. Figure 2C The function curve shown in (Condenser refrigerant vapor enthalpy curve) calculates the condenser refrigerant vapor enthalpy H3', and further calculates the condenser refrigerant flow rate (G Rc ), the calculation formula is as follows:

[0063]

[0064] Among them, Q c represents the condenser heat exchange calculated above, and H3 represents the condenser refrigerant enthalpy value (i.e. the refrigerant enthalpy value H3 of the condenser returning to the evaporator mentioned above). Figure 2C The horizontal axis represents the solution temperature near the generator solution outlet, the vertical axis represents the refrigerant vapor enthalpy of the condenser, and the three curves represent different condenser refrigerant temperatures (for example, the condenser refrigerant temperatures from top to bottom are 36°C, 34°C and 32°C respectively).

[0065] The refrigerant flow rate (G Rce ).

[0066] In some other embodiments, the refrigerant flow rate (G) from the condenser to the evaporator may not be measured by the refrigerant flow sensor 216. Rce ), firstly measure the evaporator refrigerant temperature and the condenser refrigerant temperature respectively through the evaporator refrigerant temperature sensor 212 and the condenser refrigerant temperature sensor 214, and then calculate the evaporator internal pressure P1 (kPa) and the condenser internal pressure P3 (kPa) respectively through the evaporator refrigerant temperature and the condenser refrigerant temperature according to the physical properties of the refrigerant. Taking water as an example, the relationship between its temperature and pressure is as follows Figure 2D Then calculate the refrigerant flow rate (G from the condenser to the evaporator) by the following formula Rce ):

[0067]

[0068] Among them, C vc-e represents the comprehensive flow coefficient of the third pipeline 175, which is determined by the structure of the unit and is related to the design of the pipeline (i.e., the refrigerant pipeline from the condenser to the evaporator) and the throttling device. It is usually a test value or an empirical value and can be set according to the actual value in the program. For example, in the embodiment of the present application, C vc-e Set to 11.0.

[0069] Compare the refrigerant flow rate of the evaporator (G Re), refrigerant flow rate of condenser (G Rc ) and the refrigerant flow from the condenser to the evaporator (G Rce ) and the evaporator liquid level and condenser liquid level monitored by the evaporator liquid level monitoring device 222 and the condenser liquid level monitoring device 224, the cause of the refrigerant cold loss can be comprehensively determined. Usually, the causes of the refrigerant cold loss may include the following: refrigerant overflow of the evaporator or condenser, refrigerant vapor in the evaporator carrying refrigerant liquid into the absorber, and the refrigerant pump power is too large to cause the refrigerant liquid to be flushed into the absorber, etc.

[0070] Specifically, if the refrigerant flow rate (G Rce ) is less than the refrigerant flow rate of the condenser (G Rc ), it is determined that the condenser 140 of the air-conditioning system 100 has a refrigerant loss, and an alarm is sent to the user through the user interaction interface of the control device 206 to prompt the user that "the condenser has a refrigerant loss".

[0071] If the refrigerant flow from condenser to evaporator (G Rce ) is greater than the refrigerant flow rate of the evaporator (G Re ), it is determined that the evaporator 110 of the air-conditioning system 100 has a refrigerant cold loss, and it is necessary to further determine the specific cause of the refrigerant cold loss of the evaporator 110.

[0072] Furthermore, the evaporator liquid level monitoring device 222 can be used to determine whether the evaporator refrigerant liquid level is higher than the overflow liquid level (target value). If the evaporator refrigerant liquid level is not higher than the overflow liquid level, the overflow valve 234 is kept in a closed state; if the evaporator refrigerant liquid level is higher than the overflow liquid level, the overflow valve 234 is opened, so that a part of the refrigerant in the evaporator 110 is passed into the condenser 140 to reduce the refrigerant liquid level of the evaporator 110; at the same time, the condenser refrigerant liquid level is monitored by the condenser liquid level monitoring device 224 to determine whether it is higher than the target liquid level (the position of the bottom row of heat exchange tubes of the condenser). If the condenser refrigerant liquid level is higher than the target liquid level, the overflow valve 234 is closed. If the condenser refrigerant liquid level has reached the target liquid level and the overflow valve 234 has been closed, but the evaporator refrigerant liquid level is still higher than the overflow liquid level (target value), an alarm is given to the user through the user interaction interface of the control device 206 to prompt that "the refrigerant is too much and some refrigerant needs to be extracted".

[0073] If the refrigerant level in the condenser has reached the target level, the overflow valve 234 has been closed, and the refrigerant level in the evaporator is not higher than the overflow level (target value), the opening of the self-circulation valve 232 is adjusted to the minimum opening (the minimum opening of the self-circulation valve 232 is the opening corresponding to the minimum flow rate of the evaporator liquid distribution) and maintained for a period of time, for example, 30 minutes. After the minimum opening of the circulation valve 232 is maintained for the target time, it is re-determined whether the evaporator 110 has a refrigerant loss (that is, the refrigerant flow rate (Q from the condenser to the evaporator) is determined. Rce ) is greater than the refrigerant flow rate of the evaporator (G Re )).

[0074] If the evaporator 110 still suffers from refrigerant loss, an alarm will be given to the user through the user interaction interface of the control device 206 to prompt "the evaporator suffers from refrigerant loss"; if the evaporator 110 does not suffer from refrigerant loss, the unit will return to normal operation.

[0075] Figure 3 It is a schematic diagram of the refrigerant vapor entering the absorber from the evaporator, and is used to illustrate the working principle of solving the evaporator refrigerant cold loss by reducing the opening of the self-circulation valve 232.

[0076] like Figure 3 As shown, the evaporator refrigerant vapor outlet 178 is actually formed by the structure of the liquid baffle 302. The liquid baffle 302 is arranged between the evaporator 110 and the absorber 120, and has a plurality of baffles 303, and a gap is provided between two adjacent baffles, for allowing the refrigerant vapor to enter the absorber 120 from the evaporator 110. The plurality of baffles 303 are inclined downward toward the evaporator 110, for blocking the refrigerant droplets from entering the absorber 120 from the evaporator 110. A refrigerant liquid distributor 304 is arranged at the top of the evaporator 110, which is in fluid communication with the self-circulation pipeline 177, that is, under the action of the refrigerant pump 161, the self-circulation pipeline 177 transfers the refrigerant at the lower part of the evaporator 110 to the refrigerant liquid distributor 304. After the refrigerant passes through the refrigerant liquid distribution device 304, it is distributed to the surface of the first layer of heat exchange tubes 311. After part of the refrigerant on the surface of the first layer of heat exchange tubes 311 is evaporated, the remaining part becomes droplets gathered at the bottom of the first heat exchange tube 311, and the droplets then drip onto the surface of the second layer of heat exchange tubes 312. After part of the refrigerant on the surface of the second layer of heat exchange tubes 312 is evaporated, the remaining part becomes droplets gathered at the bottom of the second heat exchange tubes 312, and the droplets then drip onto the surface of the third layer of heat exchange tubes 313, and so on. When the droplets of the upper layer fall onto the surface of the heat exchange tubes of the lower layer, due to the influence of the gravity of the droplets themselves, small droplets will be splashed around the heat exchange tubes. The small droplets may be carried by the refrigerant vapor through the liquid baffle 302 and enter the absorber 120, causing refrigerant cold loss. The more small droplets there are, the easier it is to be brought into the absorber 120, and the easier it is to cause refrigerant cold loss.

[0077] After the self-circulation valve 232 is adjusted down, the refrigerant flow rate entering the refrigerant distribution device 304 is reduced, thereby reducing the amount of refrigerant distributed per unit length of the heat exchange tube, and reducing the splashing of solution between the refrigerant distribution device 304 and the first layer of heat exchange tubes 311 and between the upper and lower layers of heat exchange tubes, as well as the number of small droplets, thereby reducing the possibility of refrigerant droplets being brought into the absorber 120, thereby reducing or eliminating refrigerant cold losses.

[0078] In actual applications, when there are gaps between the refrigerant liquid distribution device 304 and the shell of the evaporator, and between the liquid baffle 302 and the evaporator tube sheet and shell due to assembly deviation or welding quality, the refrigerant can also enter the absorber through the gaps, causing refrigerant cold loss, or because the pumping power of the refrigerant pump 161 is too large, droplets splash and cause refrigerant to enter the absorber; by reducing the refrigerant flow entering the refrigerant liquid distribution device 304, or reducing the pumping power of the refrigerant pump 161, such cold loss can also be reduced or eliminated. The above principles for reducing or eliminating cold loss are the same, which is to reduce the possibility of refrigerant entering the absorber 120 by reducing refrigerant splashing.

[0079] Figures 4A-4B This is a control flow chart for online judgment of refrigerant cooling loss, where: Figure 4A This is the first part of the control flow chart for online judgment of refrigerant cooling loss. Figure 4B This is the second part of the control flow chart for online judgment of refrigerant cooling loss.

[0080] like Figure 4A As shown, in step 402 , the control process of online determining the cooling loss of the refrigerant is started, and the process proceeds to step 404 .

[0081] In step 404, the air conditioning system is kept running normally, and the data detected by the above sensors in the air conditioning system are obtained and fed back to the control device 206. At this time, the self-circulation valve 232 is in a fully open state, and the overflow valve 234 is in a closed state. After completing the operation of step 404, the operation goes to step 406.

[0082] In step 406, the refrigerant flow rate (G Rc ) and the refrigerant flow rate of the evaporator (G Re ), determine the refrigerant flow rate of the condenser (G Rc ) is greater than the refrigerant flow rate of the evaporator (G Re If the refrigerant flow rate of the condenser (G Rc ) is greater than the refrigerant flow rate of the evaporator (G Re ), the operation goes to step 410; if the refrigerant flow rate of the condenser (G Rc ) is not greater than the refrigerant flow rate of the evaporator (G Re), it may be a load change or failure of the unit, which will not occur when the unit is in stable operation. At this time, the operation returns to step 404 or shuts down for inspection.

[0083] In step 410, the refrigerant flow rate (G Rc ), refrigerant flow rate of evaporator (G Re ), and determine the refrigerant flow rate from the condenser to the evaporator (G Rce ), two conditions are judged at the same time, namely, the refrigerant flow from the condenser to the evaporator (G Rce ) and the refrigerant flow rate of the condenser (G Rc ) and determine the refrigerant flow rate (G Rce ) and the refrigerant flow rate of the evaporator (G Re )’s size relationship.

[0084] If we judge the refrigerant flow rate from condenser to evaporator (G Rce ) and the refrigerant flow rate of the condenser (G Rc ), the operation goes to step 412 to determine the refrigerant flow rate (G Rce ) is less than the refrigerant flow rate of the condenser (G Rc If the refrigerant flow from the condenser to the evaporator (G Ece ) is less than the refrigerant flow rate of the condenser (G Rc ), indicating that the condenser has a refrigerant loss, the operation goes to step 416; if the refrigerant flow rate from the condenser to the evaporator (G Rce ) is not less than the refrigerant flow rate of the condenser (G Rc ), indicating that there is no refrigerant loss in the condenser, and the operation returns to step 404.

[0085] In step 416, the user interface of the control device 206 warns the user that "the condenser has experienced a cold loss of refrigerant." After completing step 416, the operation proceeds to step 442 (see Figure 4B ).

[0086] If we judge the refrigerant flow rate from condenser to evaporator (G Rce ) and the refrigerant flow rate of the evaporator (G Re ), the operation goes to step 414 to determine the refrigerant flow rate (G Rce ) is greater than the refrigerant flow rate of the evaporator (G Re If the refrigerant flow from the condenser to the evaporator (G Rce ) is greater than the refrigerant flow rate of the evaporator (G Re ), the operation goes to step 418; if the refrigerant flow from the condenser to the evaporator (GRce ) is not greater than the refrigerant flow rate of the evaporator (G Re ), the operation returns to step 404.

[0087] In step 418, it is determined whether the evaporator refrigerant liquid level is higher than the overflow liquid level (liquid level target value). If the evaporator refrigerant liquid level is higher than the overflow liquid level, the operation proceeds to step 420; if the evaporator refrigerant liquid level is not higher than the overflow liquid level, the operation proceeds to step 424, and the overflow valve 234 is kept in a closed state.

[0088] In step 420, it is determined whether the refrigerant liquid level of the condenser is higher than the overflow liquid level (liquid level target value). If the refrigerant liquid level of the condenser 140 is not higher than the overflow liquid level, it means that the overflow operation can be performed on the condenser 140, and the operation goes to step 422, and the overflow valve 234 is opened, so that a part of the refrigerant in the evaporator 110 is passed into the condenser 140 to reduce the refrigerant liquid level of the evaporator 110. If the refrigerant liquid level of the condenser 140 is higher than the overflow liquid level, it means that the overflow operation cannot be performed on the condenser 140, and the operation goes to step 424, and the overflow valve 234 is kept in a closed state.

[0089] In step 424, after the overflow valve 234 is closed, the operation proceeds to step 426 (see Figure 4B ).

[0090] like Figure 4B As shown, in step 426, the refrigerant flow rate (G Rce ) is greater than the refrigerant flow rate of the evaporator (G Re If the refrigerant flow from the condenser to the evaporator (G Rce ) is not greater than the refrigerant flow rate of the evaporator (G Re ), it means that passing a portion of the refrigerant in the evaporator 110 into the condenser 140 to reduce the refrigerant liquid level in the evaporator 110 is helpful to improve the refrigerant cold loss of the evaporator, and the operation goes to step 428; if the refrigerant flow rate from the condenser to the evaporator (G Rce ) is greater than the refrigerant flow rate of the evaporator (G Re ), indicating that refrigerant cold loss is still occurring, the operation proceeds to step 430.

[0091] In step 428 , an alarm is given to the user through the user interface of the control device 206 to remind the user that “the evaporator has a refrigerant cold loss, which is caused by refrigerant overflow.” After the operation of step 428 is completed, the operation proceeds to step 442 .

[0092] In step 430, it is determined whether the evaporator refrigerant level is higher than the overflow level. If the evaporator refrigerant level is still higher than the overflow level, it means that passing a portion of the refrigerant in the evaporator 110 into the condenser 140 cannot reduce the refrigerant level in the evaporator 110 to below the overflow level, and the operation proceeds to step 432; if the evaporator refrigerant level is not higher than the overflow level, the operation proceeds to step 434.

[0093] In step 432 , an alarm is given to the user through the user interface of the control device 206 to remind the user that “the refrigerant is too much and some refrigerant needs to be extracted.” After the operation of step 432 is completed, the operation proceeds to step 442 .

[0094] In step 434, the opening of the self-circulation valve 232 is adjusted to the minimum opening (the minimum opening of the self-circulation valve 232 is the opening corresponding to the minimum flow rate of the evaporator liquid distribution) and maintained for a period of time, for example, 30 minutes. After the minimum opening of the circulation valve 232 is maintained for the target operation time, the operation goes to step 436.

[0095] In step 436, the refrigerant flow rate (G Rce ) is greater than the refrigerant flow rate of the evaporator (G Re If the refrigerant flow from the condenser to the evaporator (G Rce ) is not greater than the refrigerant flow rate of the evaporator (G Re ), it means that reducing the opening of the self-circulation valve 232 to the minimum opening is helpful to improve the refrigerant cold loss of the evaporator, and the possibility of refrigerant droplets being brought into the absorber 120 is reduced, and the operation goes to step 438; if the refrigerant flow rate from the condenser to the evaporator (G Rce ) is greater than the refrigerant flow rate of the evaporator (G Re ), the operation goes to step 440.

[0096] In step 438 , the user interface of the control device 206 warns the user that “the evaporator has a refrigerant cold loss, and the refrigerant vapor carries the refrigerant liquid into the absorber.” After completing step 428 , the operation proceeds to step 442 .

[0097] In step 440, reducing the opening of the self-circulation valve 232 to the minimum opening does not help improve the refrigerant loss of the evaporator, and the cause of the refrigerant loss needs to be further confirmed, so an alarm is given to the user through the user interaction interface of the control device 206 to prompt "the evaporator has refrigerant loss, and the cause needs to be further confirmed". After completing the operation of step 440, the operation goes to step 442.

[0098] In step 442, determine whether to shut down. If not, the operation goes to step 404 and repeats the above process. If it is determined to shut down, the operation goes to step 444 to complete and end the control process of online judgment of refrigerant loss.

[0099] Figure 5 This is a component block diagram of the second embodiment of the air conditioning system of the present application. The second embodiment is substantially the same as the first embodiment in terms of unit components, except that the evaporator refrigerant temperature sensor 212 and the condenser refrigerant temperature sensor 214 are replaced by the evaporator pressure sensor 512 and the condenser pressure sensor 514, and the same parts are not repeated here.

[0100] exist Figure 5 In the second embodiment of the air conditioning system shown in the figure, the evaporator pressure sensor 512 and the condenser pressure sensor 514 respectively measure the evaporator internal pressure P1 (kPa) and the condenser internal pressure P3 (kPa), and then according to Figure 2D The evaporator refrigerant temperature and the condenser refrigerant temperature are calculated by using the evaporator internal pressure P1 and the condenser internal pressure P3, and then the evaporator refrigerant temperature and the condenser refrigerant temperature are used to perform the relevant calculations and controls in the first embodiment.

[0101] Compared with measuring the temperature in the evaporator and condenser, measuring the pressure in the evaporator and condenser can reduce the cost of the entire air conditioning system unit.

[0102] Figure 6 FIG. 2 is a block diagram of the control device in detail, showing the main components of the control device 206. The control device 206 can store and execute the following Figures 4A-4B Procedure, storage and call shown in the flow chart Figures 4A-4B Parameters required for the process.

[0103] like Figure 6 As shown, the control device 206 includes a bus 602, a processor 604, a memory 606, an input interface 608, and an output interface 610. The processor 604, the memory 606, the input interface 608, and the output interface 610 are connected to the bus 602. The processor 604 can read a program (or instruction) from the memory 606 and execute the program (or instruction) to process data; the processor 604 can also write data or a program (or instruction) into the memory 606. The memory 606 can store programs (instructions) or data. By executing the instructions in the memory 606, the processor 604 can control the memory 606, the input interface 608, and the output interface 610.

[0104] In the present application, the memory 606 can store the Figures 4A-4B The program of the process shown in and the operating parameters required to execute the program.

[0105] The input interface 608 is configured to receive data from the sensors or devices described above (such as Figure 2A and Figure 5 The processor 604 can detect feedback signals and user input signals, and the data of these parameters are converted into signals recognizable by the processor 604 and stored in the memory 606.

[0106] The processor 604 is configured to input the signal parameters stored in the memory 606 into the program, so as to obtain the state that each valve should be adjusted and analyze the cause of the refrigerant cold loss.

[0107] The output interface 610 is configured to receive the state that each valve should be adjusted from the processor 604, thereby generating a control signal for the opening or opening degree of each valve, and receive the analyzed cause of the refrigerant cold loss from the processor 604, and control the opening and closing and opening degree of each valve (self-circulation valve 232 and overflow valve 234) through the control line 612, and output to the user interaction interface through the control line 614 to feedback information on the cause of the refrigerant cold loss to the user.

[0108] The method for online determination of refrigerant cold loss of the present application and the air conditioning system using the method can at least achieve the following beneficial technical effects:

[0109] First, the present application can determine online whether refrigerant cold loss occurs in the air-conditioning system through real-time monitoring and calculation, and can accurately determine whether the location of the cold loss is the evaporator or the condenser.

[0110] Second, the present application can avoid cold loss caused by excessive evaporator circulation (excessive refrigerant pump flow or power) by adjusting the opening of the refrigerant pump valve outlet valve (self-circulation valve 232).

[0111] Third, the present application can pass part of the evaporator refrigerant into the condenser through a bypass valve to avoid cold loss caused by overflow of the evaporator.

[0112] Fourthly, the present application can provide an alarm for cold loss occurring in the condenser.

[0113] Fifth, the present application can determine whether the refrigerant loss is caused by excessive refrigerant charging and issue an alarm.

[0114] Sixth, the present application can provide an alarm for cold loss caused by unknown reasons in the evaporator.

[0115] Although the present application has been described in conjunction with the examples of the embodiments summarized above, various alternatives, modifications, changes, improvements and / or substantially equivalent solutions, whether known or currently or foreseeable in the near future, may be apparent to those skilled in the art. In addition, the technical effects and / or technical problems described in this specification are exemplary rather than restrictive; so the disclosure in this specification may be used to solve other technical problems and have other technical effects and / or may solve other technical problems. Therefore, the examples of the embodiments of the present application as stated above are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit or scope of the present application. Therefore, the present application is intended to include all known or earlier developed alternatives, modifications, changes, improvements and / or substantially equivalent solutions.

Claims

1. A method for online judgment of refrigerant cooling loss, characterized in that The following steps are involved: S01, obtain data; S02, determine the refrigerant flow rate (G of the condenser) according to the data Rc ), refrigerant flow rate of evaporator (G Re ) and the refrigerant flow from the condenser to the evaporator (G Rce ); S03, determining the refrigerant flow rate (G Rc ), the refrigerant flow rate of the evaporator (G Re ) and the refrigerant flow rate from the condenser to the evaporator (G Rce )’s size relationship; S04, if the refrigerant flow rate (G Rc ) is greater than the refrigerant flow rate from the condenser to the evaporator (G Rce ), it is determined that the condenser has a refrigerant loss; if the refrigerant flow from the condenser to the evaporator (G Rce ) is greater than the refrigerant flow rate (G Re ) to determine whether the evaporator has refrigerant loss.

2. The method for online determination of refrigerant cold loss according to claim 1, characterized in that: In step S04, if the refrigerant flow rate (G Rce ) is greater than the refrigerant flow rate (G Re ), step S04 further comprises: Step S04-1, if the evaporator refrigerant level is higher than the evaporator overflow level and the condenser refrigerant level is not higher than the condenser overflow level, open the overflow valve; Step S04-2: If the overflow valve is opened so that the refrigerant level in the evaporator is not higher than the overflow level in the evaporator, and the refrigerant flow rate from the condenser to the evaporator (G Rce ) is not greater than the refrigerant flow rate of the evaporator (G Re ), it is determined that the cause of refrigerant loss in the evaporator is refrigerant overflow.

3. The method for online determination of refrigerant cold loss according to claim 2, characterized in that: Step S04-2 further includes: if opening the overflow valve cannot reduce the refrigerant level of the evaporator to the evaporator overflow level, and the refrigerant level of the condenser is higher than the condenser overflow level, and at this time the refrigerant flow rate (G Rce ) is greater than the refrigerant flow rate (G Re ), judging that the refrigerant is overcharged.

4. The method for online determination of refrigerant cooling loss according to claim 2 or 3, characterized in that: In step S04-2, the overflow valve is closed before determining the cause of refrigerant loss in the evaporator or determining that the refrigerant is overfilled.

5. The method for online determination of refrigerant cooling loss according to claim 2, characterized in that: Step S04-2 further includes: if the overflow valve is opened so that the evaporator refrigerant level is not higher than the evaporator overflow level, and at this time the refrigerant flow rate (G Rce ) is greater than the refrigerant flow rate (G Re ), reduce the opening of the evaporator self-circulation valve.

6. The method for online determination of refrigerant cooling loss according to claim 5, characterized in that: Step S04 further includes: Step S04-3, determining the refrigerant flow rate (G Rce ) is greater than the refrigerant flow rate (G Re ), If the refrigerant flow rate from the condenser to the evaporator (G Rce ) is not greater than the refrigerant flow rate of the evaporator (G Re ), it is judged that the reason for the refrigerant loss in the evaporator is that the refrigerant vapor carries the refrigerant liquid into the absorber.

7. The method for online determination of refrigerant cooling loss according to claim 6, characterized in that: Step S04-3 further includes: If the refrigerant flow rate from the condenser to the evaporator (G Rce ) is greater than the refrigerant flow rate (G Re ), indicating that the cause of the refrigerant loss in the evaporator needs further confirmation.

8. The method for online determination of refrigerant cooling loss according to claim 1, characterized in that: The acquired data includes unit detection data and unit setting data, The unit detection data includes cold water inlet temperature (TCHWi), cold water outlet temperature (TCHWo), condenser cooling water inlet temperature (TCWci), condenser cooling water outlet temperature (TCWco), evaporator refrigerant temperature, condenser refrigerant temperature and generator solution outlet temperature; The unit setting data includes the design value of the cold water inlet temperature (TCHWid), the design value of the cold water outlet temperature (TCHWod), the design value of the unit cooling capacity (Q ed ), design value of cooling water inlet temperature (TCWid), design value of cooling water outlet temperature (TCWod), design value of unit heat dissipation (Q acd ).

9. The method for online determination of refrigerant cooling loss according to claim 8, characterized in that: The evaporator refrigerant vapor enthalpy (H1') can be determined according to the evaporator refrigerant temperature; The condenser refrigerant enthalpy (H3) can be determined according to the condenser refrigerant temperature; The condenser refrigerant vapor enthalpy (H3') can be determined according to the generator solution outlet temperature and the condenser refrigerant temperature; According to the cold water inlet temperature (TCHWi), the cold water outlet temperature (TCHWo), the cold water inlet water temperature design value (TCHWid), the cold water outlet water temperature design value (TCHWod) and the unit cooling capacity design value (Q ed ) can determine the cooling capacity of the unit (Q e );as well as According to the condenser cooling water inlet temperature (TCWci), the condenser cooling water outlet temperature (TCWco), the cooling water inlet water temperature design value (TCWid), the cooling water outlet water temperature design value (TCWod) and the unit heat dissipation design value (Q acd ) can determine the condenser heat transfer (Q c ).

10. The method for online determination of refrigerant cooling loss according to claim 9, characterized in that: According to the cooling capacity of the unit (Q e ), the evaporator refrigerant vapor enthalpy value (H1') and the condenser refrigerant enthalpy value (H3) can determine the evaporator refrigerant flow rate (G Re );as well as According to the condenser heat exchange (Q c ), the condenser refrigerant enthalpy value (H3) and the condenser refrigerant vapor enthalpy value (H3') can determine the refrigerant flow rate (G Rc ).

11. The method for online determination of refrigerant cooling loss according to claim 8, characterized in that: The unit detection data also includes the refrigerant flow rate (G Rce );or The refrigerant flow rate from the condenser to the evaporator (G Rce ) can be determined by the evaporator refrigerant temperature and the condenser refrigerant temperature.

12. The method for online determination of refrigerant cold loss according to claim 8, characterized in that: The unit detection data also includes measuring the evaporator internal pressure and the condenser internal pressure. The evaporator refrigerant temperature can be determined according to the evaporator internal pressure, and the condenser refrigerant temperature can be determined according to the condenser internal pressure.

13. An air conditioning system, comprising an evaporator, an absorber, a generator, a condenser and a control device, wherein the evaporator is connected to the condenser through a pipeline, and the absorber is connected to the generator through a pipeline, characterized in that: The cause and location of the refrigerant loss are determined by the method for online determination of the refrigerant loss as described in any one of claims 1 to 12.

14. The air conditioning system according to claim 13, characterized in that: An overflow pipeline is arranged between the evaporator and the condenser.

Images