Second-class absorption heat pump system and control system and method thereof

Abstract

The invention provides a control system for a second-class absorption heat pump unit and a control method of the control system. The second-class absorption heat pump unit comprises an evaporator, an absorber, a condenser and a generator. A control system includes a fluid flow control assembly and a control device. And the fluid flow control assembly is connected with the second-class absorption heat pump unit. A control device is coupled to the fluid flow control assembly and is configured to control operation of the fluid flow control assembly. The fluid flow control assembly is configured to operate to control fluid flow in the second type absorption heat pump unit so as to adjust the liquid level of a refrigerant in the evaporator and the concentration of a solution in the generator. According to the control method, the corrosion damage of the solution in the generator to the unit and the reduction of the COP of the unit caused by the high hot water return temperature of the absorber can be prevented, and the temperature threshold value of the hot water return temperature of the absorber can be set to be high, so that the unit is prevented from being shut down frequently.

Description

Technical Field

[0001] The present application relates to a second type of absorption heat pump system, and particularly to a control system and method for a second type of absorption heat pump unit. Background Art

[0002] In a lithium bromide second type of absorption heat pump system, waste heat is supplied to an evaporator to evaporate the refrigerant in the evaporator, a driving heat source is supplied to a generator to concentrate the lithium bromide solution in the generator, hot water in a pipe network enters an absorber, and after being heated, directly provides a heat source to the outside without entering a condenser. Cooling water is only supplied to the condenser for the condenser to cool the refrigerant vapor coming from the generator. Summary of the Invention

[0003] The inventors found that when the temperature of the hot water entering from the hot water inlet of the absorber is relatively high during the operation of the current lithium bromide second type of heat pump unit, the temperature and concentration of the dilute solution flowing out from the solution outlet of the absorber will increase. After the dilute solution enters the generator and is heated and concentrated, the temperature and concentration of the concentrated solution flowing out from the solution outlet of the generator also increase. Since the temperature and concentration of the concentrated solution in the second type of heat pump unit are already relatively close to the strong corrosion concentration, the corrosion damage to the unit caused by the higher concentration of the concentrated solution generated in the generator will be greatly enhanced. For example, the pipes of the unit and the container shells of the absorber and the generator are made of iron. When the concentration of the lithium bromide solution is higher than, for example, 65%, it will show strong corrosiveness, thus corroding and damaging the unit.

[0004] The inventors also found that when the temperature of the hot water entering from the hot water inlet of the absorber is relatively high, the ability of the absorber to absorb the refrigerant vapor from the evaporator will decrease, resulting in an increase in the evaporator pressure, and further resulting in a decrease in the refrigerant evaporation amount in the evaporator. Eventually, the refrigerant water entering the evaporator from the condenser will accumulate in the evaporator, causing the liquid level height of the refrigerant water to increase. When the refrigerant water in the evaporator further accumulates and the liquid level reaches the height of the overflow port, the refrigerant water in the evaporator will enter the absorber through the overflow port and mix with the dilute solution in the absorber. Then, the mixed dilute solution in the absorber enters the generator and is heated and evaporated into refrigerant vapor in the generator. Then, the refrigerant vapor is condensed by the condenser and then enters the evaporator again. That is to say, in the above cycle of the unit, the refrigerant water in the evaporator does not exchange heat with the waste heat in the heat exchange tubes, so that the driving heat source used by the generator does not exert a heating effect, resulting in a decrease in the COP of the unit. The COP during partial load operation of the unit will be much lower than that during full load operation.

[0005] The prior art monitors the hot water return temperature of the absorber and sets a temperature warning value. When the hot water return temperature is higher than this temperature warning value, the unit shuts down and alarms. However, when the hot water temperature at the hot water inlet of the absorber is relatively high, it will cause the concentration of the strong solution in the generator to increase, resulting in a significant increase in the corrosion damage of the unit (such as the pipelines of the unit, the container shells of the absorber and the generator) and a decrease in the COP of the unit. Therefore, the prior art sets the temperature warning value of the hot water return temperature at the hot water inlet of the absorber relatively low, for example, close to the lowest hot water return temperature allowed for the operation of the unit. As a result, the unit is very likely to shut down frequently because the hot water return temperature is higher than this temperature warning value. Moreover, the hot water return temperature in the pipe network of the unit often fluctuates uncontrollably, so there is often a risk of frequent shutdowns of the unit.

[0006] To solve the above problems, the present application sets up a fluid flow control component to control the fluid flow in the second type of absorption heat pump unit, so as to adjust the liquid level of the refrigerant in the evaporator and the concentration of the solution in the generator. When the hot water return temperature of the absorber is relatively high, the present application adjusts the liquid level of the refrigerant in the evaporator to prevent excessive accumulation of refrigerant water in the evaporator and overflow into the absorber, resulting in a decrease in the COP of the unit, and adjusts the concentration of the solution in the generator to prevent the concentration of the strong solution in the generator from increasing, which enhances the corrosion damage to the unit and the decrease in the COP of the unit. Therefore, the present application can also prevent the corrosion damage of the solution in the generator to the unit and the decrease in the COP of the unit when the hot water return temperature of the absorber is relatively high. Thus, the temperature threshold of the hot water return temperature of the absorber can be set relatively high to prevent the unit from shutting down frequently, thereby enhancing the market competitiveness of the product.

[0007] Specifically, the fluid flow control component is disposed between the evaporator and / or absorber and the condenser and / or generator. The fluid flow control component includes a pipeline and a valve disposed in the pipeline. The valve is used to control the flow of refrigerant vapor from the evaporator and / or absorber to the condenser and / or generator via the pipeline. More specifically, when the valve is opened upon detecting that the return water temperature of the hot water in the absorber is high, since the pressure in the evaporator and absorber is much greater than the pressure in the condenser and generator, the refrigerant vapor in the evaporator and / or absorber will bypass to the condenser and / or generator, thereby reducing the concentration of the strong solution in the generator. Moreover, when the valve is opened, the pressure in the generator will increase, thereby inhibiting the capacity of the generator and reducing the concentration of the strong solution flowing out from the solution outlet of the generator. Therefore, the present application can prevent the concentration of the strong solution in the generator from increasing and enhance the corrosion damage to the unit. And when the valve is opened and the pressure in the generator increases to inhibit the capacity of the generator, the heat utilized in the generator decreases. Since the COP of the unit is approximately equal to the heat generated in the absorber divided by the heat utilized in the generator, the decrease in the heat utilized in the generator will cause the COP of the unit to increase. Also, when the regulating valve is opened upon detecting that the return water temperature of the hot water in the absorber is high, the liquid level of the refrigerant water in the evaporator will decrease, preventing the refrigerant water in the evaporator from overflowing into the absorber and causing the COP of the unit to decrease.

[0008] Specifically, according to the first aspect of the present application, the present application provides a control system for a second-type absorption heat pump unit, which includes an evaporator, an absorber, a condenser, and a generator. The control system includes a fluid flow control component and a control device. The fluid flow control component is connected to the second-type absorption heat pump unit. The control device is connected to the fluid flow control component and is configured to control the operation of the fluid flow control component. The fluid flow control component is configured to operate to control the fluid flow in the second-type absorption heat pump unit to adjust the liquid level of the refrigerant in the evaporator and the concentration of the solution in the generator.

[0009] According to the first aspect of the present application, the control device is configured to control the operation of the fluid flow control component based on the temperature of the hot water entering the absorber and the liquid level of the refrigerant in the evaporator.

[0010] According to the first aspect of the present application, the fluid flow control component is disposed between the steam outlet of the first component and the steam inlet of the second component to control the flow of refrigerant vapor from the first component to the second component. The first component includes at least one of the evaporator and the absorber. The second component includes at least one of the condenser and the generator.

[0011] According to the first aspect of the present application, the fluid flow control assembly includes a pipeline and a valve. The pipeline is arranged between the first component and the second component. The valve is arranged in the pipeline and configured to control the flow of refrigerant vapor from the first component to the second component via the pipeline.

[0012] According to the first aspect of the present application, the control device is configured to control the operation of the fluid flow control assembly based on the temperature of the hot water entering the absorber and the liquid level of the refrigerant in the evaporator, including: when the temperature of the hot water entering the absorber meets the temperature condition, controlling the operation of the fluid flow control assembly based on the liquid level of the refrigerant in the evaporator; and when the temperature of the hot water entering the absorber does not meet the temperature condition, stopping the operation of the fluid flow control assembly.

[0013] According to the first aspect of the present application, when the temperature of the hot water entering the absorber meets the temperature condition, controlling the operation of the fluid flow control assembly based on the liquid level of the refrigerant in the evaporator includes: controlling the operation of the fluid flow control assembly based on the liquid level value, rise and rising rate of the refrigerant in the evaporator.

[0014] According to the first aspect of the present application, the control device includes a processor. The processor is configured to perform the following operations S1 - S5. In operation S1, it is determined whether the temperature of the hot water entering the absorber is higher than the temperature threshold. When the temperature of the hot water entering the absorber is not higher than the temperature threshold, the valve is controlled to close and the process proceeds to operation S5. When the temperature of the hot water entering the absorber is higher than the temperature threshold, the liquid level of the refrigerant in the evaporator is determined and the process proceeds to operation S2. In operation S2, when the liquid level of the refrigerant in the evaporator reaches the overflow liquid level threshold, the valve is controlled to open fully and the process proceeds to operation S5. When the liquid level of the refrigerant in the evaporator does not reach the overflow liquid level threshold, it is determined whether the liquid level of the refrigerant in the evaporator is higher than the first liquid level threshold and the process proceeds to operation S3. In operation S3, when the liquid level of the refrigerant in the evaporator is higher than the first liquid level threshold, the valve is controlled to open by a certain opening degree and the process proceeds to operation S5. When the liquid level of the refrigerant in the evaporator is not higher than the first liquid level threshold, it is determined whether the liquid level of the refrigerant in the evaporator reaches the second liquid level threshold and the process proceeds to operation S4. In operation S4, when the liquid level of the refrigerant in the evaporator reaches the second liquid level threshold, the valve is controlled to maintain the current state and the process proceeds to operation S5. When the liquid level of the refrigerant in the evaporator does not reach the second liquid level threshold, the valve is controlled to close and the process proceeds to operation S5. In operation S5, the second - type absorption heat pump unit is controlled to operate for a predetermined time, and then the process returns to operation S1 until the control of the valve ends. The overflow liquid level threshold is greater than the first liquid level threshold, and the first liquid level threshold is greater than the second liquid level threshold.

[0015] According to the first aspect of the present application, in operation S3, when the liquid level of the refrigerant in the evaporator is higher than the first liquid level threshold, controlling the valve to open by a certain opening degree includes the following operations S3.1 - S3.2. In operation S3.1, it is determined whether the current liquid level of the refrigerant in the evaporator has increased relative to the previous liquid level. When the current liquid level of the refrigerant in the evaporator has increased relative to the previous liquid level, the rising rate of the liquid level of the refrigerant in the evaporator is determined and the process proceeds to operation S3.2. When the current liquid level of the refrigerant in the evaporator has not increased relative to the previous liquid level, the valve is controlled to open to a predetermined opening degree and the process proceeds to operation S5. In operation S3.2, when the rising rate of the liquid level of the refrigerant in the evaporator does not exceed the rising rate threshold, the valve is controlled to increase the opening degree at a first rate and the process proceeds to operation S5. When the rising rate of the liquid level of the refrigerant in the evaporator exceeds the rising rate threshold, the valve is controlled to increase the opening degree at a second rate and the process proceeds to operation S5. The first rate is less than the second rate, and the opening degree increased by the valve at the first rate after the predetermined time is greater than the predetermined opening degree.

[0016] According to the first aspect of the present application, the second liquid level threshold is greater than the full-load liquid level value, and the full-load liquid level value is the liquid level value of the refrigerant in the evaporator when the second type of absorption heat pump unit operates normally at full load.

[0017] According to the first aspect of the present application, the control system further includes a temperature detection device and a liquid level detection device. The temperature detection device is configured to detect the temperature of the hot water entering the absorber. The liquid level detection device is configured to detect the liquid level of the refrigerant in the evaporator.

[0018] According to the second aspect of the present application, the present application provides a second type of absorption heat pump system. The second type of absorption heat pump system includes a second type of absorption heat pump unit and the above-mentioned control system.

[0019] According to the third aspect of the present application, the present application provides a control method for a second type of absorption heat pump unit. The control method includes controlling the operation of the second type of absorption heat pump unit through the above-mentioned control system. Description of the Drawings

[0020] The drawings are not drawn to scale. In the drawings, each identical or almost identical component shown in different figures is denoted by the same reference numeral. For the sake of clarity, not every component may be labeled in each drawing. In the drawings:

[0021] Figure 1 A structural block diagram of a second type of absorption heat pump system according to an embodiment of the present application is shown;

[0022] Figure 2A Shows Figure 1 A schematic structural diagram of a first embodiment of the second type of absorption heat pump unit and the control system shown;

[0023] Figure 2B Shows Figure 1 A schematic structural diagram of a second embodiment of the second type of absorption heat pump unit and the control system shown;

[0024] Figure 2C Shows Figure 1 A schematic structural diagram of a third embodiment of the second type of absorption heat pump unit and the control system shown;

[0025] Figure 2D Shows Figure 1 A schematic structural diagram of a fourth embodiment of the second type of absorption heat pump unit and the control system shown;

[0026] Figure 3 A flowchart of the control method for a second type of absorption heat pump unit according to the present application is shown;

[0027] Figure 4 shows Figure 3 a detailed flowchart of step 306 shown; and

[0028] Figure 5 shows Figure 1 a structural block diagram of the control device shown. Detailed implementation manners

[0029] Various specific implementation manners of the present application will be described below with reference to the drawings forming a part of this specification. It should be understood that, where possible, the same or similar reference numerals used in the present application refer to the same components.

[0030] Figure 1 shows a structural block diagram of a second type of absorption heat pump system 100 according to an embodiment of the present application.

[0031] As Figure 1 shown, the second type of absorption heat pump system 100 includes a second type of absorption heat pump unit 101 and a control system 102. The control system 102 is connected to the second type of absorption heat pump unit 101 and is configured to control the operation of the second type of absorption heat pump unit 101. The second type of absorption heat pump unit 101 includes an evaporator, an absorber, a condenser, and a generator (see details in Figures 2A - 2D ).

[0032] The control system 102 includes a fluid flow control component 103, a temperature detection device 104, a liquid level detection device 105, and a control device 106. The fluid flow control component 103 is connected to the second type of absorption heat pump unit 101 through a connection line 111 and is configured to operate to control the flow of fluid in the second type of absorption heat pump unit 101. The temperature detection device 104 is connected to the second type of absorption heat pump unit 101 through a connection line 112 and is configured to detect and obtain, for example, the temperature of the hot water entering the absorber from the hot water inlet of the absorber. The liquid level detection device 105 is connected to the second type of absorption heat pump unit 101 through a connection line 113 and is configured to detect and obtain the liquid level of the refrigerant in the evaporator. The temperature detection device 104 is connected to the control device 106 through a connection line 114 to output the obtained temperature of the hot water entering the absorber to the control device 106. The liquid level detection device 105 is connected to the control device 106 through a connection line 115 to output the obtained liquid level of the refrigerant in the evaporator to the control device 106. The control device 106 processes based on the received temperature of the hot water entering the absorber and the liquid level of the refrigerant in the evaporator to generate a control signal. The control device 106 is connected to the fluid flow control component 103 through a connection line 116 and is configured to output the control signal to the fluid flow control component 103 to control the operation of the fluid flow control component 103. For example, the fluid flow control component 103 is configured to operate to control the fluid flow in the second type of absorption heat pump unit 101 to adjust the liquid level of the refrigerant in the evaporator and the concentration of the solution in the generator. The control device 106 is also connected to the second type of absorption heat pump unit 101 through a connection line 117 and is configured to control the operation of the second type of absorption heat pump unit 101. The above connection lines represent data connection lines, signal connection lines, connection pipelines, physical position connections, etc. In other embodiments, the second type of absorption heat pump system includes other suitable structures.

[0033] Figure 2A shows Figure 1 a schematic structural diagram of the first embodiment of the second type of absorption heat pump unit 101 and the control system 102 shown, Figure 2B shows Figure 1 a schematic structural diagram of the second embodiment of the second type of absorption heat pump unit 101 and the control system 102 shown, Figure 2C shows Figure 1 a schematic structural diagram of the third embodiment of the second type of absorption heat pump unit 101 and the control system 102 shown, Figure 2D shows Figure 1 a schematic structural diagram of the fourth embodiment of the second type of absorption heat pump unit 101 and the control system 102 shown, in which the control device 106 in the control system 102 is not shown.

[0034] AsFigures 2A - 2D As shown, the second type of absorption heat pump unit 101 includes an evaporator 201, an absorber 202, a condenser 203, and a generator 204. Waste heat enters the evaporator 201 from the waste heat inlet 210 and flows out from the waste heat outlet 211. The waste heat flowing through the evaporator 201 evaporates the refrigerant, such as water, in the evaporator 201 into refrigerant vapor. The refrigerant vapor flows from the evaporator 201 to the absorber 202. The strong lithium bromide solution in the absorber 202 absorbs the refrigerant vapor and then becomes a weak lithium bromide solution, while releasing the absorption heat to heat the hot water flowing through the absorber 202. The hot water enters the absorber 202 from the hot water inlet 212, is heated up, and outputs the heated hot water from the hot water outlet 213. The weak solution in the absorber 202 is pumped to the heat exchanger 209 via the first pump 205. After the weak solution is cooled by the heat exchanger 209, it flows to the generator 204. The driving heat source is supplied to the generator 204 from the driving heat source inlet 216 and flows out from the driving heat source outlet 217. The driving heat source heats the lithium bromide solution in the generator 204 to generate refrigerant vapor and strong lithium bromide solution. The refrigerant vapor flows from the generator 204 to the condenser 203. The cooling water enters the condenser 203 from the cooling water inlet 214 and flows out from the cooling water outlet 215. The cooling water flowing through the condenser 203 condenses the refrigerant vapor into refrigerant liquid, which is pumped to the evaporator 201 via the second pump 206. Also, the strong lithium bromide solution in the generator 204 is pumped to the heat exchanger 209 via the third pump 207, and then flows to the absorber 202. In the evaporator 201, the refrigerant is pumped to the top of the evaporator 201 by the fourth pump 208. When the liquid level of the refrigerant in the evaporator 201 is too low, for example, lower than the cavitation liquid level height, the fourth pump 208 stops working.

[0035] The hot water entering the absorber 202 from the hot water inlet 212 has a relatively high temperature, which will cause the generator 204 to produce a strong solution with a higher concentration, thus greatly enhancing the corrosion damage to the second type of absorption heat pump unit 101, and will also cause excessive accumulation of the refrigerant in the evaporator 201 to overflow from the overflow port 225 of the evaporator 201 into the absorber 202, thereby reducing the COP of the second type of absorption heat pump unit 101. In this application, a fluid flow control component 103 is provided to control the fluid flow in the second type of absorption heat pump unit 101 to adjust the liquid level of the refrigerant in the evaporator 201 and the concentration of the solution in the generator 204.

[0036] ​Specifically, the fluid flow control component 103 of the present application is arranged between the steam outlet of the first component and the steam inlet of the second component to control the flow of refrigerant steam from the first component to the second component. The first component includes at least one of an evaporator 201 and an absorber 202, and the second component includes at least one of a condenser 203 and a generator 204. The present application controls the flow of refrigerant steam from the above-mentioned first component to the above-mentioned second component to simultaneously adjust the liquid level of the refrigerant in the evaporator 201 and the concentration of the solution in the generator 204. This control is simple and reliable, and the required improvement cost is relatively low. In one embodiment, the fluid flow control component 103 includes a pipeline and a valve arranged in the pipeline. The pipeline is arranged between the first component and the second component. The valve is configured to control the flow of refrigerant steam from the first component via the pipeline to the second component.

[0037] As Figure 2A shown, the fluid flow control component 103 is arranged between the steam outlet 221 of the evaporator 201 and the steam inlet 223 of the condenser 203. The fluid flow control component 103 includes a pipeline 231 arranged between the steam outlet 221 of the evaporator 201 and the steam inlet 223 of the condenser 203 and a valve 220 arranged in the pipeline 231. The valve 220 controls the flow of refrigerant steam from the evaporator 201 via the pipeline 231 to the condenser 203.

[0038] Figure 2B The structure shown is basically similar to Figure 2A the structure shown, except that in Figure 2B , the fluid flow control component 103 is arranged between the steam outlet 221 of the evaporator 201 and the steam inlet 224 of the generator 204. The fluid flow control component 103 includes a pipeline 232 arranged between the steam outlet 221 of the evaporator 201 and the steam inlet 224 of the generator 204 and a valve 220 arranged in the pipeline 232. The valve 220 controls the flow of refrigerant steam from the evaporator 201 via the pipeline 232 to the generator 204.

[0039] Figure 2C The structure shown is basically similar to Figure 2A the structure shown, except that in Figure 2C , the fluid flow control component 103 is arranged between the steam outlet 222 of the absorber 202 and the steam inlet 223 of the condenser 203. The fluid flow control component 103 includes a pipeline 233 arranged between the steam outlet 222 of the absorber 202 and the steam inlet 223 of the condenser 203 and a valve 220 arranged in the pipeline 233. The valve 220 controls the flow of refrigerant steam from the absorber 202 via the pipeline 233 to the condenser 203.

[0040] Figure 2D the structure shown is basically similar toFigure 2A The structures shown are basically similar. However, in Figure 2D , the fluid flow control component 103 is arranged between the steam outlet 222 of the absorber 202 and the steam inlet 224 of the generator 204. The fluid flow control component 103 includes a pipeline 234 arranged between the steam outlet 222 of the absorber 202 and the steam inlet 224 of the generator 204 and a valve 220 arranged in the pipeline 234. The valve 220 controls the flow of refrigerant steam from the absorber 202 to the generator 204 via the pipeline 234.

[0041] When the temperature of the hot water entering the absorber 202 from the hot water inlet 212 is relatively high and the valve 220 is opened, since the pressure in the evaporator 201 and the absorber 202 is much greater than the pressure in the condenser 203 and the generator 204, the refrigerant steam in the evaporator 201 and / or the absorber 202 will bypass to the condenser 203 and / or the generator 204, thereby reducing the concentration of the strong solution in the generator 204. Moreover, when the valve 220 is opened, the pressure in the generator 204 will increase, thereby inhibiting the capacity of the generator 204 and reducing the concentration of the strong solution flowing out from the solution outlet of the generator 204. Therefore, the present application can prevent the concentration of the strong solution in the generator 204 from increasing and enhance the corrosion damage to the second type of absorption heat pump unit 101. And when the valve 220 is opened and the pressure in the generator 204 increases to inhibit the capacity of the generator 204, the heat utilized in the generator 204 decreases. And the COP of the unit is approximately equal to the heat generated in the absorber 202 divided by the heat utilized in the generator 204. Therefore, the decrease in the heat utilized in the generator 204 will cause the COP of the unit to increase. And when the valve 220 is opened, the liquid level of the refrigerant water in the evaporator 201 will decrease, preventing the refrigerant water in the evaporator 201 from overflowing to the absorber 202 through the overflow port 225 and causing the COP of the unit to decrease. Based on this, the present application can set the temperature threshold of the hot water entering the absorber 202 to be relatively high, thereby preventing the second type of absorption heat pump unit 101 from frequently stopping.

[0042] Figure 3 The flowchart of the control method 300 for the second type of absorption heat pump unit according to the present application is shown. The control method 300 for the second type of absorption heat pump unit is controlled and executed by the control device 106. The control device 106 is configured to control the operation of the fluid flow control component 103 based on the temperature of the hot water entering the absorber 202 and the liquid level in the evaporator 201 to adjust the liquid level of the refrigerant in the evaporator 201 and the concentration of the solution in the generator 204.

[0043] As Figure 3As shown, at step 302, the control method 300 for the second type of absorption heat pump unit starts to execute, and then proceeds from step 302 to step 304.

[0044] At step 304, it is determined whether the temperature of the hot water entering the absorber 202 meets the condition. If the temperature of the hot water entering the absorber 202 meets the condition, then it proceeds from step 304 to step 306. For example, the condition includes that the temperature of the hot water entering the absorber 202 is higher than the temperature threshold. If the temperature of the hot water entering the absorber 202 is higher than the temperature threshold, it indicates that the temperature of the hot water entering the absorber 202 is too high, and the operation of the fluid flow control component 103 needs to be controlled. If the temperature of the hot water entering the absorber 202 does not meet the condition, then it proceeds from step 304 to step 308. At step 308, the fluid flow control component 103 is stopped from operating, for example, controlling the valve 220 in the fluid flow control component 103 to close.

[0045] At step 306, the operation of the fluid flow control component 103 is controlled based on the liquid level of the refrigerant in the evaporator 201, and then it proceeds from step 306 to step 310. For example, at step 306, the operation of the fluid flow control component 103 is controlled based on the liquid level value, rise and rise rate of the refrigerant in the evaporator 201.

[0046] At step 310, wait for the second type of absorption heat pump unit 101 to operate for a period of time (predetermined time), and then it proceeds from step 310 to step 312.

[0047] At step 312, it is determined whether the control process needs to end. If the control process does not need to end, then it proceeds from step 312 to step 304 to repeat the execution of the above control method. If the control process needs to end, then it proceeds from step 312 to step 314. At step 314, the execution of the control method 300 for the second type of absorption heat pump unit ends. In other embodiments, the present application includes other suitable control methods to achieve the above functions.

[0048] Figure 4 Shows Figure 3 The detailed flowchart of step 306 shown above.

[0049] The present application controls the operation of the valve 220 in the fluid flow control assembly 103 based on the liquid level value, rise and fall, and rising rate of the refrigerant in the evaporator 201. The present application sets a first liquid level threshold and a second liquid level threshold for the liquid level of the refrigerant in the evaporator 201 to control the operation of the valve 220, thereby preventing the problem of frequent opening and closing of the valve caused by controlling the operation of the valve 220 only through one liquid level threshold. The first liquid level threshold and the second liquid level threshold are greater than the full load liquid level value. The full load liquid level value is the liquid level value of the refrigerant in the evaporator 201 when the second type of absorption heat pump unit 101 operates normally at full load. When the liquid level of the refrigerant in the evaporator 201 is higher than the higher first liquid level threshold, the possibility of overflow of the refrigerant in the evaporator 201 is judged by the rise and fall of the liquid level, and then the operation of the valve 220 is controlled accordingly to control the corresponding change of the liquid level. And, the corresponding opening rate of the valve 220 is determined by the rising rate of the liquid level, and the rise of the liquid level is controlled accordingly to prevent the refrigerant in the evaporator 201 from rising too fast and overflowing into the absorber 202. The above control operation makes the operation of the second type of absorption heat pump unit 101 stable without large fluctuations while avoiding or reducing the overflow of the refrigerant in the evaporator 201 into the absorber 202.

[0050] As Figure 4 shown, it transfers from step 304 in Figure 3 to step 402 in Figure 4 . At step 402, it is judged whether the liquid level h of the refrigerant in the evaporator 201 reaches the overflow liquid level threshold h 溢 . If the liquid level h of the refrigerant in the evaporator 201 reaches the overflow liquid level threshold h 溢 , it indicates that the accumulated liquid level h of the refrigerant in the evaporator 201 is too high, then it transfers from step 402 to step 404. At step 404, the valve 220 is fully opened, and then it transfers from step 404 to Figure 3 step 310 in 溢 . If the liquid level h of the refrigerant in the evaporator 201 does not reach the overflow liquid level threshold h

[0051] , then it transfers from step 402 to step 406.

[0051] At step 406, it is judged whether the liquid level h of the refrigerant in the evaporator 201 is higher than the first liquid level threshold h 1 . If the liquid level h of the refrigerant in the evaporator 201 is higher than the first liquid level threshold h 1 , it indicates that the liquid level h of the refrigerant in the evaporator 201 is relatively high and the valve 220 may need to be opened, then it transfers from step 406 to step 408. If the liquid level h of the refrigerant in the evaporator 201 is not higher than the first liquid level threshold h 1 , then it transfers from step 406 to step 410. The overflow liquid level threshold h 溢 is greater than the first liquid level threshold h 1。

[0052] At step 408, it is determined whether the current liquid level h of the refrigerant in the evaporator 201 has increased relative to the previous liquid level h', for example, whether the liquid level difference Δh (h - h') between the two is greater than zero. If the current liquid level h of the refrigerant in the evaporator 201 has increased relative to the previous liquid level h', then it transfers from step 408 to step 412. If the current liquid level h of the refrigerant in the evaporator 201 has not increased relative to the previous liquid level h', then it transfers from step 408 to step 414. At step 414, the control valve 220 is opened to a predetermined opening P1, and then it transfers from step 414 to Figure 3 step 310 in

[0053] At step 412, it is determined whether the rising speed rate Vh of the liquid level of the refrigerant in the evaporator 201 exceeds the rising speed rate threshold. For example, the rising speed rate threshold is 40%. In other embodiments, other suitable rising speed rate thresholds can be set. If the rising speed rate Vh of the liquid level of the refrigerant in the evaporator 201 does not exceed the rising speed rate threshold, then it transfers from step 412 to step 418. At step 418, the control valve 220 increases the opening at a first rate V1, and then it transfers from step 418 to Figure 3 step 310 in Figure 3 If the rising speed rate Vh of the liquid level of the refrigerant in the evaporator 201 exceeds the rising speed rate threshold, then it transfers from step 412 to step 416. At step 416, the control valve 220 increases the opening at a second rate V2, and then it transfers from step 416 to

[0054] step 310 in 2 The first rate V1 is less than the second rate V2. The opening increased by the control valve 220 at the first rate V1 after a period of time (predetermined time) passing through step 310 is greater than the predetermined opening P1. 2 At step 410, it is determined whether the liquid level h of the refrigerant in the evaporator 201 reaches the second liquid level threshold h 1 The second liquid level threshold h 2 is less than the first liquid level threshold h Figure 3 If the liquid level h of the refrigerant in the evaporator 201 reaches the second liquid level threshold h 2 , then it transfers from step 410 to step 420. At step 420, the control valve 220 maintains the current state, and then it transfers from step 420 to Figure 3 step 310 in 1 If the liquid level h of the refrigerant in the evaporator 201 does not reach the second liquid level threshold h 2。In other embodiments, the present application includes other suitable control methods to achieve the above functions.

[0055] Figure 5 shows Figure 1 a structural block diagram of the control device shown. As Figure 5 shown, the control device 106 includes a processor 502, a memory 503, an input interface 504, an output interface 505, and a bus 501. The processor 502, the memory 503, the input interface 504, and the output interface 505 are connected to the bus 501. The processor 502 can read a program (or instruction) from the memory 503 and execute the program (or instruction) to perform data processing. The processor 502 can also write data or a program (or instruction) into the memory 503. The memory 503 can store a program (or instruction) or data. By executing the instructions in the memory 503, the processor 502 can control the memory 503, the input interface 504, and the output interface 505.

[0056] The input interface 504 is configured to receive the hot water temperature from the temperature detection device 104 (i.e., the temperature of the hot water entering the absorber 202) through the connection line 114, and receive the liquid level (i.e., the liquid level of the refrigerant in the evaporator 201) from the liquid level detection device 105 through the connection line 115.

[0057] The input interface 504 is further configured to convert the received data (e.g., hot water temperature, liquid level, etc.) into data recognizable by the processor 502 and output the data to the processor 502. The processor 502 is configured to process (e.g., calculate) the received data to generate a control signal.

[0058] The output interface 505 is configured to receive a control signal from the processor 502, convert the control signal into a signal suitable for the fluid flow control component 103 and the second type of absorption heat pump unit 101, and send a drive control signal to the fluid flow control component 103 through the connection line 116, and send a drive control signal to the second type of absorption heat pump unit 101 through the connection line 117. In one embodiment, the processor 502 is configured to generate a control signal for the fluid flow control component 103 based on the hot water temperature from the temperature detection device 104 and the liquid level from the liquid level detection device 105. The control signal includes control signals for the valve 220 to be fully opened, closed, opened to a predetermined opening degree P1, increased at a first rate V1, increased at a second rate V2, and maintained in the current state.

[0059] Although the present application has been described in connection with examples of the embodiments outlined above, various alternatives, modifications, variations, improvements and / or substantially equivalent alternatives, whether known or now or soon foreseeable, may be apparent to those of at least ordinary skill in the art. Additionally, the technical effects and / or technical problems described in this specification are exemplary rather than restrictive; so the disclosures in this specification may be used to solve other technical problems and have other technical effects and / or may solve other technical problems. Accordingly, 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. Accordingly, the present application is intended to cover all known or earlier developed alternatives, modifications, variations, improvements and / or substantially equivalent alternatives.

Claims

1. A control system (102) for a second type absorption heat pump unit, wherein the second type absorption heat pump unit (101) comprises an evaporator (201), an absorber (202), a condenser (203) and a generator (204), characterized in that: The control system (102) comprises: a fluid flow control assembly (103), which is connected to the second type absorption heat pump unit (101); and a control device (106) connected to the fluid flow control assembly (103) and configured to control the operation of the fluid flow control assembly (103), Wherein, the fluid flow control component (103) is configured to operate to control the fluid flow in the second type absorption heat pump unit (101) to adjust the liquid level of the refrigerant in the evaporator (201) and the concentration of the solution in the generator (204).

2. The control system (102) for the second type absorption heat pump unit according to claim 1, wherein: The control device (106) is configured to control the operation of the fluid flow control assembly (103) based on the temperature of the hot water entering the absorber (202) and the liquid level of the refrigerant in the evaporator (201).

3. The control system (102) for the second type absorption heat pump unit according to claim 1, wherein: The fluid flow control assembly (103) is disposed between a steam outlet (221, 222) of the first component and a steam inlet (223, 224) of the second component to control the flow of refrigerant steam from the first component to the second component. The first component includes at least one of the evaporator (201) and the absorber (202), and the second component includes at least one of the condenser (203) and the generator (204).

4. The control system (102) for the second type absorption heat pump unit according to claim 3, wherein: The fluid flow control assembly (103) comprises: a pipeline (231, 232, 233, 234) disposed between the first component and the second component; and A valve (220) is disposed in the pipeline (231, 232, 233, 234) and is configured to control the flow of refrigerant vapor from the first component to the second component via the pipeline (231, 232, 233, 234).

5. The control system (102) for the second type absorption heat pump unit according to claim 2, wherein: The control device (106) is configured to control the operation of the fluid flow control assembly (103) based on the temperature of the hot water entering the absorber (202) and the liquid level of the refrigerant in the evaporator (201), including: When the temperature of the hot water entering the absorber (202) satisfies the temperature condition, the operation of the fluid flow control assembly (103) is controlled based on the liquid level of the refrigerant in the evaporator (201); and When the temperature of the hot water entering the absorber (202) does not meet the temperature condition, the fluid flow control assembly (103) stops operating.

6. The control system (102) for the second type absorption heat pump unit according to claim 5, wherein: When the temperature of the hot water entering the absorber (202) satisfies the temperature condition, the operation of controlling the fluid flow control assembly (103) based on the liquid level of the refrigerant in the evaporator (201) comprises: The operation of the fluid flow control assembly (103) is controlled based on the liquid level value, rise and fall, and rising rate of the refrigerant liquid level in the evaporator (201).

7. The control system (102) for the second type absorption heat pump unit according to claim 4, wherein: The control device (106) comprises a processor (502), wherein the processor (502) is configured to perform the following operations: S1: determining whether the temperature of the hot water entering the absorber (202) is higher than a temperature threshold; when the temperature of the hot water entering the absorber (202) is not higher than the temperature threshold, controlling the valve (220) to close and proceeding to operation S5; when the temperature of the hot water entering the absorber (202) is higher than the temperature threshold, determining the liquid level of the refrigerant in the evaporator (201) and proceeding to operation S2; S2: when the liquid level of the refrigerant in the evaporator (201) reaches the overflow liquid level threshold, controlling the valve (220) to be fully opened and switching to operation S5; when the liquid level of the refrigerant in the evaporator (201) does not reach the overflow liquid level threshold, determining whether the liquid level of the refrigerant in the evaporator (201) is higher than the first liquid level threshold and switching to operation S3; S3: when the liquid level of the refrigerant in the evaporator (201) is higher than the first liquid level threshold, the valve (220) is controlled to open to a certain degree and the process proceeds to operation S5; when the liquid level of the refrigerant in the evaporator (201) is not higher than the first liquid level threshold, it is determined whether the liquid level of the refrigerant in the evaporator (201) has reached a second liquid level threshold and the process proceeds to operation S4; S4: when the liquid level of the refrigerant in the evaporator (201) reaches the second liquid level threshold, the valve (220) is controlled to maintain the current state and the process proceeds to operation S5; when the liquid level of the refrigerant in the evaporator (201) does not reach the second liquid level threshold, the valve (220) is controlled to close and the process proceeds to operation S5; and S5: Control the second type absorption heat pump unit (101) to run for a predetermined time, and then switch to operation S1 until the control of the valve (220) is terminated. Among them, the overflow liquid level threshold is greater than the first liquid level threshold, and the first liquid level threshold is greater than the second liquid level threshold.

8. The control system (102) for the second type absorption heat pump unit according to claim 7, wherein: In the operation S3, when the liquid level of the refrigerant in the evaporator (201) is higher than the first liquid level threshold, controlling the valve (220) to open to a certain degree comprises: S3.1: determining whether the current liquid level of the refrigerant in the evaporator (201) has increased relative to the previous liquid level; when the current liquid level of the refrigerant in the evaporator (201) has increased relative to the previous liquid level, determining the rate of increase of the liquid level of the refrigerant in the evaporator (201) and proceeding to operation S3.2; when the current liquid level of the refrigerant in the evaporator (201) has not increased relative to the previous liquid level, controlling the valve (220) to open to a predetermined opening and proceeding to operation S5; and S3.2: When the rate of increase of the liquid level of the refrigerant in the evaporator (201) does not exceed the rate of increase threshold, the valve (220) is controlled to increase its opening at a first rate and the operation is turned to S5; when the rate of increase of the liquid level of the refrigerant in the evaporator (201) exceeds the rate of increase threshold, the valve (220) is controlled to increase its opening at a second rate and the operation is turned to S5; The first rate is smaller than the second rate, and the increased opening of the valve (220) after the predetermined time when the opening increases at the first rate is greater than the predetermined opening.

9. The control system (102) for the second type absorption heat pump unit according to claim 7, wherein: The second liquid level threshold is greater than a full load liquid level value, and the full load liquid level value is the liquid level value of the refrigerant in the evaporator (201) when the second type absorption heat pump unit (101) operates normally at full load.

10. The control system (102) for the second type absorption heat pump unit according to claim 2, wherein: The control system (102) further includes: a temperature detection device (104) configured to detect the temperature of the hot water entering the absorber (202); and A liquid level detection device (105) is configured to detect the liquid level of the refrigerant in the evaporator (201).

11. A second type absorption heat pump system (100), characterized in that: The second type absorption heat pump system (100) comprises: A second type absorption heat pump unit (101); and A control system (102) according to claims 1-10.

12. A control method (300) for a second type absorption heat pump unit, characterized in that: The control method (300) comprises: The operation of the second type absorption heat pump unit (101) is controlled by the control system (102) described in claims 1 to 10.

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