An absorption heat pump system and a control method thereof

Abstract

The present application belongs to the technical field of absorption heat pump, and discloses an absorption heat pump system and a control method thereof.The heat pump system comprises a generator, a compressor, a condenser and a refrigeration subsystem.The gas outlet of the generator is connected with the compressor, the compressor is connected with the inlet of the condenser, the refrigeration subsystem comprises a refrigerant throttling valve, a first evaporator and a first absorber connected in sequence, the outlet of the condenser is connected with the inlet of the refrigerant throttling valve, the outlet of the first absorber is connected with the inlet of the generator, the liquid outlet of the generator is connected with the inlet of the first absorber, and the first evaporator is used for providing cold quantity.The present application adds the compressor between the generator and the condenser, when the temperature of the driving heat source is low, the pressure difference between the generator side and the condenser side can be increased by improving the compression degree, which is beneficial to the stable operation of the generation process, maintains or improves the operation performance of the system, and can be used for the efficient recovery of low-grade heat energy in the production and life fields.

Description

Technical Field

[0001] This invention belongs to the technical field of absorption heat pumps, and more specifically, relates to an absorption heat pump system and its control method. Background Technology

[0002] Absorption heat pump technology uses medium-to-high temperature heat energy as the driving heat source. It establishes pressure and temperature differences through changes in the concentration of the working fluid in the solution and phase changes in the refrigerant, outputting high-quality cold or heat energy. Compared to vapor compression heat pumps, absorption heat pumps have advantages such as low power consumption and good environmental performance, and are widely used in heat recovery and other fields.

[0003] Current absorption heat pump technology commonly uses lithium bromide aqueous solution and ammonia aqueous solution as the working fluid. Current absorption heat pump technology generally provides the driving heat energy for system operation using a heat source of at least 80°C. For driving heat energy exceeding 100°C, dual-effect or triple-effect configurations can achieve efficient energy utilization. However, when the driving heat source is below 80°C, absorption heat pump systems suffer from poor operating performance and other technical problems, making them unsuitable for the efficient recovery of lower-grade heat energy in production and daily life. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides an absorption heat pump system and its control method, which solves the technical problem that the existing absorption heat pump system has poor operating performance when the driving heat source temperature is low, and cannot be used for efficient recovery of low-grade heat energy in production and life. By adding a compressor to adjust the pressure ratio between the generator side and the condenser side, the heat energy demand of the generation process in the generator can be reduced, which is conducive to the stable operation of the generation process.

[0005] To achieve the above objectives, according to one aspect of the present invention, an absorption heat pump system is provided, comprising a generator, a compressor, a condenser, and a refrigeration subsystem. The generator is used to neutralize the evaporation of refrigerant with a working fluid to form a gaseous refrigerant and a concentrated solution. The gas outlet of the generator is connected to the inlet of the compressor, and the outlet of the compressor is connected to the inlet of the condenser. The refrigeration subsystem comprises a refrigerant throttling valve, a first evaporator, and a first absorber connected in sequence. The outlet of the condenser is connected to the inlet of the refrigerant throttling valve, the outlet of the first absorber is connected to the inlet of the generator, and the liquid outlet of the generator is connected to the inlet of the first absorber. The first evaporator is used to provide cooling capacity.

[0006] According to the absorption heat pump system provided by the present invention, the liquid outlet of the generator is connected to the first absorber through a concentrated solution throttling valve, and the outlet of the first absorber is connected to the generator through a first solution pump.

[0007] According to the absorption heat pump system provided by the present invention, the refrigeration subsystem further includes a first solution heat exchanger, wherein the liquid outlet of the generator flows through a first process of the first solution heat exchanger and then into the first absorber, and the outlet of the first absorber flows through a second process of the first solution heat exchanger and then into the generator.

[0008] The absorption heat pump system provided by the present invention further includes a heating subsystem, which includes a refrigerant pump, a second evaporator, and a second absorber connected in sequence. The outlet of the condenser is connected to a refrigerant flow regulating valve, which is connected to the refrigerant throttling valve and the refrigerant pump, respectively. The liquid outlet of the generator is connected to a concentrated solution flow regulating valve, which is connected to the first absorber and the second absorber, respectively. The outlet of the second absorber is connected to the inlet of the generator, and the second absorber is used to provide heat.

[0009] According to the absorption heat pump system provided by the present invention, the liquid outlet of the generator is connected to the second absorber via a second solution pump, and the outlet of the second absorber is connected to the inlet of the generator via a dilute solution throttling valve.

[0010] According to the absorption heat pump system provided by the present invention, the heating subsystem further includes a second solution heat exchanger, wherein the liquid outlet of the generator flows through a first process of the second solution heat exchanger and then into the second absorber, and the outlet of the second absorber flows through a second process of the second solution heat exchanger and then into the generator.

[0011] According to the absorption heat pump system provided by the present invention, the first evaporator and the second evaporator respectively include a shell and a heat exchange tube disposed inside the shell. The shell is provided with a refrigerant inlet and an outlet, and one end of a spray pipe is connected to the bottom of the shell, and the other end of the spray pipe extends from the top of the shell into the interior of the shell.

[0012] According to another aspect of the present invention, a control method for an absorption heat pump system is provided, based on the absorption heat pump system described in any of the preceding claims, the control method comprising:

[0013] The compression degree of the compressor is adjusted according to the temperature of the driving heat source. As the temperature of the driving heat source decreases, the compression degree of the compressor is gradually increased.

[0014] According to the absorption heat pump system control method provided by the present invention, the absorption heat pump system further includes a heating subsystem, which includes a refrigerant pump, a second evaporator, and a second absorber connected in sequence. The outlet of the condenser is connected to a refrigerant flow regulating valve, which is connected to the refrigerant throttling valve and the refrigerant pump respectively. The liquid outlet of the generator is connected to a concentrated solution flow regulating valve, which is connected to the first absorber and the second absorber respectively. The outlet of the second absorber is connected to the inlet of the generator. The second absorber is used to provide heat.

[0015] The control method further includes:

[0016] Design the rated operating conditions of the system;

[0017] Based on the rated operating conditions of the system, determine the adjustment ratio between the refrigerant flow regulating valve and the concentrated solution flow regulating valve;

[0018] The refrigerant flow regulating valve and the concentrated solution flow regulating valve are adjusted and controlled according to the aforementioned adjustment ratio.

[0019] According to the absorption heat pump system control method provided by the present invention, the refrigerant flow regulating valve and the concentrated solution flow regulating valve are regulated and controlled according to the following proportional relationship:

[0020]

[0021]

[0022]

[0023] Among them, R r R represents the proportion of the refrigerant mass flow rate from the outlet of the refrigerant flow regulating valve to the refrigeration subsystem. n X represents the proportion of the concentrated solution flowing from the outlet of the concentrated solution flow regulating valve to the refrigeration subsystem by mass flow rate. s X is the solvent concentration of the concentrated solution at the liquid outlet of the generator; w1 X is the solvent concentration of the dilute solution at the outlet of the first absorber; w2 X is the solvent concentration of the dilute solution at the outlet of the second absorber; s X w1 and X w2 The design parameters are determined based on the rated operating conditions of the system.

[0024] In summary, compared with the prior art, the absorption heat pump system and its control method provided by this invention offer the following advantages:

[0025] 1. By adding a compressor between the generator and the condenser, the pressure ratio between the generator side and the condenser side can be adjusted by changing the degree of refrigerant compression, thereby controlling the concentration difference between the concentrated and dilute solutions in the system. When the temperature of the driving heat source is low, the pressure difference between the generator side and the condenser side can be increased by increasing the degree of compression, reducing the heat energy demand of the generation process in the generator, which is conducive to the stable operation of the generation process, maintaining or improving the operating performance of the system. Thus, the heat pump system can still achieve good operating performance when the driving heat source is below 80°C, and can be used for the efficient recovery of low-grade heat energy in production and daily life.

[0026] 2. It combines absorption cooling and heating technologies, enabling cooling and heating to operate independently or in parallel, and is not limited to a single cooling or heating mode;

[0027] 3. By using a flow regulating valve, the flow ratio of refrigerant and concentrated solution in the refrigeration and heating subsystems can be changed, thereby controlling the ratio of system refrigeration and heating to meet different levels of cold and heat energy supply needs. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of an absorption heat pump system provided by the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of an absorption heat pump system that operates in parallel for cooling and heating, provided by the present invention.

[0030] Figure 3 This is a schematic diagram of the cooling operation of an absorption heat pump system provided by the present invention;

[0031] Figure 4 This is a schematic diagram of the heating operation of an absorption heat pump system provided by the present invention;

[0032] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0033] 101-Refrigerant throttling valve; 102-First evaporator; 103-First solution pump; 104-First absorber; 105-Concentrated solution throttling valve; 106-First solution heat exchanger; 201-Refrigerant pump; 202-Second evaporator; 203-Second absorber; 204-Second solution heat exchanger; 205-Second solution pump; 206-Dilute solution throttling valve; 301-Concentrated solution flow regulating valve; 302-Generator; 303-Compressor; 304-Condenser; 305-Refrigerant flow regulating valve. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Please see Figure 1 This invention provides an absorption heat pump system, which includes a generator 302, a compressor 303, a condenser 304, and a refrigeration subsystem. The generator 302 is used to evaporate the refrigerant with a working fluid to form a gaseous refrigerant and a concentrated solution. The gas outlet of the generator 302 is connected to the inlet of the compressor 303, and the outlet of the compressor 303 is connected to the inlet of the condenser 304. The refrigeration subsystem includes a refrigerant throttling valve 101, a first evaporator 102, and a first absorber 104 connected in sequence. The outlet of the condenser 304 is connected to the inlet of the refrigerant throttling valve 101, the outlet of the first absorber 104 is connected to the inlet of the generator 302, and the liquid outlet of the generator 302 is connected to the inlet of the first absorber 104. The first evaporator 102 is used to provide cooling capacity.

[0036] Specifically, the outlet of the refrigerant throttling valve 101 is connected to the inlet of the first evaporator 102, and the outlet of the first evaporator 102 is connected to the inlet of the first absorber 104. The generator 302 is driven by the heat energy of the externally input heat source. It absorbs heat energy to make the working fluid evaporate while the refrigerant evaporates to form a concentrated solution. The generated refrigerant vapor flows through the compressor 303, where its pressure and temperature are increased. It then flows into the condenser 304, which relies on the cooling water input from outside the system to provide cooling capacity for cooling and condensing the refrigerant vapor.

[0037] The refrigerant throttling valve 101 throttles and reduces the pressure of the refrigerant, which then flows into the first evaporator 102. The first evaporator 102 provides cooling to the outside of the system through the evaporation of the low-temperature refrigerant. The refrigerant vapor formed by evaporation flows into the first absorber 104 and is absorbed by the concentrated solution. The first absorber 104 can absorb the heat released during the absorption process by the cooling water input from outside the system. The dilute solution 1 formed during the absorption process eventually flows into the generator 302 to form a cycle.

[0038] In this system, generator 302 is the medium-pressure side, and condenser 304 is the high-pressure side. Compressor 303 can adjust the pressure ratio between generator 302 on the medium-pressure side and condenser 304 on the high-pressure side by changing the degree of compression of the refrigerant. For example, if the degree of compression is increased under the condition that the pressure of condenser 304 is constant, the pressure of generator 302 will decrease accordingly, the concentration of the concentrated solution generated by generator 302 will increase, the concentration difference of the solution will increase, and the performance of the heat pump system will be improved. When the temperature of the driving heat source decreases, the generation temperature will decrease accordingly. At this time, the pressure of generator 302 can be reduced by increasing the degree of compression of compressor 303, thereby maintaining the generation process of generator 302 and maintaining the operating performance of the system.

[0039] The absorption heat pump system provided by this invention adds a compressor 303 between the generator 302 and the condenser 304. By changing the degree of compression of the refrigerant, the pressure ratio between the generator 302 side and the condenser 304 side can be adjusted, thereby controlling the concentration difference between the concentrated and dilute solutions in the system. When the temperature of the driving heat source is low, the pressure difference between the generator 302 side and the condenser 304 side can be increased by increasing the degree of compression, reducing the heat energy demand of the generation process in the generator 302, which is beneficial to the stable operation of the generation process and maintaining or improving the operating performance of the system. Thus, the heat pump system can still achieve good operating performance when the driving heat source is below 80°C, and can be used for the efficient recovery of low-grade heat energy in production and daily life.

[0040] Furthermore, the first evaporator 102 is equipped with a heat exchange pipe, into which working fluid water can be introduced. The working fluid water absorbs the cooling energy provided by the refrigerant inside the first evaporator 102 to form chilled water. After the chilled water is cooled, it is output to the outside and can be delivered to any place that needs cooling.

[0041] Furthermore, the novel working fluid pair used in this invention is composed of a refrigerant and a solvent; wherein the refrigerant can be a novel refrigerant, such as hydrofluorocarbons (HFCs) or hydrofluoroolefins (HFOs), and the solvent can be a novel absorbent, such as an ionic liquid. The novel working fluid pair possesses advantages such as non-toxicity, chemical stability, low corrosivity, and non-crystallization, and requires no investment in distillation equipment.

[0042] This embodiment considers the corrosiveness and tendency to crystallize in commonly used working fluid pairs, particularly the crystallization of lithium bromide aqueous solution in absorption heat pump systems when the driving heat source is below 80°C. Ammonia is toxic and requires additional distillation equipment for ammonia-water separation. The application of existing working fluid pairs limits the development and application of absorption heat pump systems. Therefore, a novel working fluid pair for absorption heat pumps is proposed. For example, novel refrigerants such as hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs) are used, along with novel absorbents such as ionic liquids and organic oils. These novel approaches avoid crystallization and corrosion, demonstrating good performance in the refrigeration process of a simulated single-effect absorption heat pump system.

[0043] Furthermore, the liquid outlet of the generator 302 is connected to the first absorber 104 via a concentrated solution throttling valve 105, and the outlet of the first absorber 104 is connected to the generator 302 via a first solution pump 103. Because the refrigerant pressure decreases after flowing through the refrigerant throttling valve 101, for the refrigeration subsystem, the first evaporator 102 and the first absorber 104 are on the low-pressure side, the generator 302 is on the medium-pressure side, and the condenser 304 is on the high-pressure side. To maintain pressure balance inside the first absorber 104 and ensure the stability of the absorption process, the medium-pressure concentrated solution flowing out of the generator 302 can first pass through the concentrated solution throttling valve 105 to reduce its pressure before flowing into the first absorber 104. Similarly, the low-pressure dilute solution 1 flowing out of the first absorber 104 can be pressurized by the first solution pump 103 before flowing into the medium-pressure generator 302, thereby stabilizing the pressure in the generator 302, which is beneficial for the stable operation of the generation process in the generator 302 and for the system circulation.

[0044] Furthermore, in this embodiment, for the refrigeration subsystem, the first evaporator 102 and the first absorber 104 are low-pressure sides, the generator 302 is a medium-pressure side, and the condenser 304 is a high-pressure side. The pressure is relative; that is, the pressure of the working fluid on the condenser 304 side is higher than that on the generator 302 and the first evaporator 102, so it is a high-pressure side. The pressure of the working fluid in the first evaporator 102 and the first absorber 104 is lower than that on the condenser 304 and the generator 302, so it is a low-pressure side. The pressure of the generator 302 is in the middle, so it is a medium-pressure side. The pressure is only used for comparison and is not used to limit specific pressure values.

[0045] Furthermore, the refrigeration subsystem also includes a first solution heat exchanger 106. The liquid outlet of the generator 302 flows through the first solution heat exchanger 106 in a first pass and then into the first absorber 104. The outlet of the first absorber 104 flows through the first solution heat exchanger 106 in a second pass and then into the generator 302. The first solution heat exchanger 106 is provided to recover and utilize the heat from the concentrated solution flowing into the refrigeration subsystem, which helps improve the system's energy utilization rate and thus improve system efficiency.

[0046] Furthermore, the liquid outlet of generator 302 can first flow through the first solution heat exchanger 106 in a first pass, then through the concentrated solution throttle valve 105, and finally into the first absorber 104. The outlet of the first absorber 104 can first flow through the first solution pump 103, then through the second pass of the first solution heat exchanger 106, and finally into the generator 302. This helps maintain the pressure balance and stability in the first solution heat exchanger 106, thereby improving heat exchange stability. The first solution heat exchanger 106 is a medium-pressure side.

[0047] Furthermore, in this embodiment, the absorption heat pump system also includes a heating subsystem, which comprises a refrigerant pump 201, a second evaporator 202, and a second absorber 203 connected in sequence. The outlet of the condenser 304 is connected to a refrigerant flow regulating valve 305, which is connected to the refrigerant throttling valve 101 and the refrigerant pump 201 respectively. The liquid outlet of the generator 302 is connected to a concentrated solution flow regulating valve 301, which is connected to the first absorber 104 and the second absorber 203 respectively. The outlet of the second absorber 203 is connected to the inlet of the generator 302, and the second absorber 203 is used to provide heat. This absorption heat pump system combines absorption refrigeration and heating technologies. By adjusting the refrigerant flow regulating valve 305 and the concentrated solution flow regulating valve 301, it can achieve independent or simultaneous parallel operation of refrigeration and heating, and is not limited to a single refrigeration or heating mode.

[0048] Specifically, the concentrated solution flow regulating valve 301 can adjust the flow distribution ratio of the concentrated solution flowing out of the generator 302, wherein the proportion of the concentrated solution flowing into the refrigeration subsystem is R. n (0≤R n ≤1), correspondingly, the remaining concentrated solution flows into the heating subsystem, accounting for a proportion of 1-R. n The refrigerant flow regulating valve 305 can adjust the flow distribution ratio of the refrigerant flowing out of the condenser 304, wherein the proportion of refrigerant flowing into the refrigeration subsystem is R. r (0≤R r ≤1), the corresponding proportion of refrigerant flowing into the heating subsystem is 1-Rr It should be noted that if R r The larger the value of R, the higher the proportion of refrigerant flowing into the refrigeration subsystem. n The larger the value, the higher the proportion of concentrated solution flowing into the refrigeration subsystem. When 0 < R r When <1, then 0 < R. n <1, the heating subsystem and the cooling subsystem are operating simultaneously and in parallel; when R r When = 0, R n =0, the refrigerant and solution circulate only between the heating subsystems; when R r When = 1, R n =1, the refrigerant and solution circulate only between the refrigeration subsystems.

[0049] Furthermore, the liquid outlet of the generator 302 is connected to the second absorber 203 via the second solution pump 205, and the outlet of the second absorber 203 is connected to the inlet of the generator 302 via the dilute solution throttling valve 206. Because the refrigerant pressure increases after flowing through the refrigerant pump 201, for the heating subsystem, the second evaporator 202 and the second absorber 203 are the highest pressure sides, with pressures higher than those of the high-pressure side condenser 304. To maintain pressure balance inside the second absorber 203 and ensure the stability of the absorption process, the medium-pressure concentrated solution flowing out of the generator 302 can be pressurized by the second solution pump 205 before flowing into the second absorber 203. Similarly, the low-pressure dilute solution 2 flowing out of the second absorber 203 can be depressurized by the dilute solution throttling valve 206 before flowing into the medium-pressure generator 302, thereby stabilizing the pressure in the generator 302, which is beneficial for the stable operation of the generation process in the generator 302 and for the system circulation.

[0050] Furthermore, in this embodiment, for the heating subsystem, the second evaporator 202 and the second absorber 203 are the highest pressure sides, with pressures higher than those of the high-pressure side condenser 304. The pressure levels are relative; that is, the pressure of the working fluid in the second evaporator 202 and the second absorber 203 is higher than that in the condenser 304, hence they are the highest pressure sides. The terms "concentrated solution" and "dilute solution" mentioned in the embodiments are also relative; that is, the concentration of the solvent in a concentrated solution is greater than that in a dilute solution. The terms "concentrated" and "dilute" are only used for comparison and do not define specific concentration values.

[0051] Furthermore, the heating subsystem also includes a second solution heat exchanger 204. The liquid outlet of the generator 302 flows through the second solution heat exchanger 204 in a first pass and then into the second absorber 203. The outlet of the second absorber 203 flows through the second solution heat exchanger 204 in a second pass and then into the generator 302. The second solution heat exchanger 204 is provided to recover and utilize the heat from the dilute solution 2 flowing out of the second absorber 203, which helps to improve the system's energy utilization rate and thus improve system efficiency.

[0052] Furthermore, the liquid outlet of generator 302 can first flow through the second solution pump 205, then through the first stage of the second solution heat exchanger 204, and finally into the second absorber 203. The outlet of the second absorber 203 can first flow through the second stage of the second solution heat exchanger 204, then through the dilute solution throttling valve 206, and finally into generator 302. This helps maintain the pressure balance and stability in the second solution heat exchanger 204, thereby improving heat exchange stability. The second solution heat exchanger 204 is the highest pressure side.

[0053] Furthermore, the refrigeration subsystem includes a refrigerant throttling valve 101, a first evaporator 102, a first solution pump 103, a first absorber 104, a concentrated solution throttling valve 105, and a first solution heat exchanger 106. The inlet of the refrigerant throttling valve 101 is connected to the refrigerant flow regulating valve 305, and the outlet is connected to the refrigerant inlet of the first evaporator 102. The refrigerant outlet of the first evaporator 102 is connected to the first absorber 104. The dilute solution outlet of the first absorber 104 is connected to the dilute solution inlet of the first solution heat exchanger 106 via the first solution pump 103. The dilute solution outlet of the first solution heat exchanger 106 is connected to the generator 302, its concentrated solution inlet is connected to the concentrated solution flow regulating valve 301, and its concentrated solution outlet is connected to the concentrated solution inlet of the first absorber 104 via the concentrated solution throttling valve 105.

[0054] Within the refrigeration subsystem, the first evaporator 102 and the first absorber 104 are on the low-pressure side, the first solution heat exchanger 106 and the generator 302 are on the medium-pressure side, and the condenser 304 is on the high-pressure side, which relies on the cooling water input from outside the system to cool and condense the refrigerant vapor.

[0055] The refrigerant throttling valve 101 throttles and reduces the pressure of the refrigerant from the refrigerant flow regulating valve 305. The refrigerant then flows into the first evaporator 102. The first evaporator 102 cools the chilled water input from outside the system through the evaporation of the low-temperature refrigerant and outputs it to the outside. The refrigerant vapor formed by evaporation flows into the first absorber 104 and is absorbed by the concentrated solution. The first absorber 104 absorbs the heat released during the absorption process by the cooling water input from outside the system. The dilute solution 1 formed during the absorption process is pumped to the first solution heat exchanger 106 by the first solution pump 103. In the first solution heat exchanger 106, the low-temperature dilute solution 1 and the high-temperature concentrated solution undergo countercurrent heat exchange. Finally, the dilute solution 1 flows into the generator 302, while the high-temperature concentrated solution, after heat exchange, is depressurized by the concentrated solution throttling valve 105 and flows into the first absorber 104.

[0056] The heating subsystem includes a refrigerant pump 201, a second evaporator 202, a second absorber 203, a second solution heat exchanger 204, a second solution pump 205, and a dilute solution throttling valve 206. The inlet of refrigerant pump 201 is connected to the refrigerant flow regulating valve 305, and the outlet of refrigerant pump 201 is connected to the refrigerant inlet of the second evaporator 202. The refrigerant outlet of the second evaporator 202 is connected to the refrigerant inlet of the second absorber 203, and the dilute solution outlet of the second absorber 203 is connected to the dilute solution inlet of the second solution heat exchanger 204. The dilute solution outlet of the second solution heat exchanger 204 is connected to the generator 302 via the dilute solution throttling valve 206, and its concentrated solution inlet is connected to the outlet of the second solution pump 205. Its concentrated solution outlet is connected to the concentrated solution inlet of the second absorber 203. The inlet of the second solution pump 205 is connected to the concentrated solution flow regulating valve 301, which can pump the concentrated solution flowing out of the generator 302 into the second solution heat exchanger 204.

[0057] The second evaporator 202, the second absorber 203, and the second solution heat exchanger 204 of the heating subsystem are on the highest pressure side, with pressures higher than those of the condenser 304 on the high pressure side.

[0058] The refrigerant flowing into the heating subsystem from the refrigerant flow regulating valve 305 is pressurized by the refrigerant pump 201 and then flows into the second evaporator 202. The refrigerant in the second evaporator 202 absorbs the heat energy from the external heat source of the system, which can be used as the driving heat source. The high-temperature vapor formed by evaporation flows into the second absorber 203 and is absorbed by the concentrated solution. The high-temperature heat energy released during the absorption process in the second absorber 203 can heat the water supplied from the external system and output high-quality high-temperature hot water. The dilute solution 2 formed during the absorption process flows into the second solution heat exchanger 204. In the second solution heat exchanger 204, the high-temperature dilute solution 2 and the low-temperature concentrated solution flowing out from the concentrated solution flow regulating valve 301 and pressurized by the second solution pump 205 exchange heat. The cooled dilute solution 2 flows into the generator 302 after throttling and depressurization, while the concentrated solution after heat exchange flows into the second absorber 203.

[0059] The absorption heat pump system for heat recovery provided by this invention utilizes an additional compressor 303 to assist the absorption heat pump, enabling efficient heat recovery even when the temperature of the driving heat source is below 80°C. It can recover heat energy below 80°C to drive system operation. Through solution circulation within the system, low-temperature chilled water and high-temperature hot water can be produced, supplying high-quality cold and heat energy respectively. This achieves heat recovery of low-temperature, low-grade heat energy, applying it to refrigeration and heating modules, thus broadening the application environment and scenarios of absorption heat pump technology and related systems. By adjusting the flow rates of refrigerant and concentrated solution, the parallel-operating refrigeration and heating subsystems are controlled, supplying a corresponding proportion of high-quality cold and heat energy to the external system.

[0060] Furthermore, the pipeline between compressor 303 and condenser 304 flows through generator 302. This allows the refrigerant to flow back into generator 302 for heat exchange and cooling, which helps to lower the refrigerant temperature and achieve heat recovery and utilization to improve system efficiency.

[0061] Furthermore, the first evaporator 102 and the second evaporator 202 each include a shell and heat exchange tubes disposed inside the shell. The shell has a refrigerant inlet and an outlet, and one end of a spray pipe is connected to the bottom of the shell. The other end of the spray pipe extends from the top of the shell into the interior of the shell. Taking the configuration of the first evaporator 102 as an example, the heat exchange tube is used to input working fluid water. The working fluid water exchanges heat with the refrigerant inside the heat exchange tube to form chilled water, which is used to provide cooling to the outside. A delivery pump can be installed on the spray pipe to transport liquid refrigerant from the bottom to the top of the shell, thereby spraying it onto the heat exchange tube from the top, which helps to improve heat exchange efficiency.

[0062] Furthermore, heat exchange pipes are provided inside the condenser 304, the first absorber 104, and the second absorber 203. Cooling water can be introduced into the heat exchange pipes inside the condenser 304 and the first absorber 104 for heat absorption and cooling. Hot water can be introduced into the heat exchange pipes inside the second absorber 203 for heat absorption and temperature increase to obtain high-temperature hot water, which can then provide heat to the outside. The generator 302 is also equipped with heat exchange pipes for introducing the driving heat source.

[0063] Furthermore, the present invention also provides a control method for an absorption heat pump system. Based on the absorption heat pump system described in any of the above embodiments, the control method includes: controlling and adjusting the compression degree of the compressor 303 according to the temperature of the driving heat source, wherein as the temperature of the driving heat source decreases, the compression degree of the compressor 303 is gradually increased.

[0064] The control method provided in this embodiment proposes to improve the system's adaptability range to the driving heat source temperature by adjusting the compression degree of the compressor 303. When the driving heat source temperature is slightly low, the compression degree of the compressor 303 can be increased, thereby reducing the pressure of the generator 302, thus maintaining the generation process of the generator 302 and maintaining the system's operating performance. This is beneficial for achieving efficient recovery of low-grade heat energy below 80°C.

[0065] Furthermore, the absorption heat pump system also includes a heating subsystem, which includes a refrigerant pump 201, a second evaporator 202, and a second absorber 203 connected in sequence. The outlet of the condenser 304 is connected to a refrigerant flow regulating valve 305, which is connected to the refrigerant throttling valve 101 and the refrigerant pump 201 respectively. The liquid outlet of the generator 302 is connected to a concentrated solution flow regulating valve 301, which is connected to the first absorber 104 and the second absorber 203 respectively. The outlet of the second absorber 203 is connected to the inlet of the generator 302. The second absorber 203 is used to provide heat.

[0066] The control method further includes:

[0067] Design the rated operating conditions of the system;

[0068] Based on the rated operating conditions of the system, determine the adjustment ratio between the refrigerant flow regulating valve 305 and the concentrated solution flow regulating valve 301;

[0069] The refrigerant flow regulating valve 305 and the concentrated solution flow regulating valve 301 are adjusted and controlled according to the adjustment ratio.

[0070] The system's rated operating conditions can be designed first based on the heat source requirements. These requirements include the temperature range of the driving heat source, cooling requirements (e.g., chilled water temperature), heating requirements (e.g., hot water supply temperature), and cooling conditions (e.g., the temperature of the cooling water flowing into the condenser and the first absorber). Rated operating condition design parameters include the outlet temperatures of the first evaporator 102, the first absorber 104, the second evaporator 202, the second absorber 203, the condenser 304, the generator 302, the efficiency of the first solution heat exchanger 106, the efficiency of the second solution heat exchanger 204, the driving heat source temperature range, and the working fluid flow rate. In other words, based on the driving heat source temperature range, a rated operating condition is designed that can provide chilled water at a lower temperature, hot water at a higher temperature, and with high system efficiency. In actual use, the heat pump system can operate according to the rated operating condition to provide chilled water and hot water at the corresponding temperatures.

[0071] Furthermore, the heat pump system involved in the control method provided in this embodiment is a multi-generation system in which the refrigeration subsystem and the heating subsystem are connected by a refrigerant flow regulating valve 305 and a concentrated solution flow regulating valve 301. When the heat pump system is in use, the specific control and adjustment of the two flow regulating valves are related to the specific cooling and heating output of the system. This embodiment proposes a control and adjustment method for the two flow regulating valves. By adjusting the two flow regulating valves through this control and adjustment method, it is beneficial to achieve the matching of refrigerant and concentrated solution flow rates in the refrigeration subsystem and the heating subsystem respectively, which is beneficial to the stable and efficient operation of the system and to better meet the external demand for cooling and heating.

[0072] Specifically, the refrigerant flow regulating valve 305 and the concentrated solution flow regulating valve 301 are adjusted and controlled according to the following proportional relationship:

[0073]

[0074]

[0075]

[0076] Among them, R r R represents the proportion of the refrigerant mass flow rate from the outlet of the refrigerant flow regulating valve 305 to the refrigeration subsystem. n X represents the mass flow rate ratio of the concentrated solution flowing from the outlet of the concentrated solution flow regulating valve 301 to the refrigeration subsystem. s X is the solvent concentration of the concentrated solution at the liquid outlet of the generator 302; w1 X is the solvent concentration of the dilute solution at the outlet of the first absorber 104; w2 X is the solvent concentration of the dilute solution at the outlet of the second absorber 203; s X w1 and X w2 The design parameters are determined based on the rated operating conditions of the system.

[0077] In other words, this embodiment proposes that after the design parameters for the rated operating conditions are determined, R can be calculated using the above formula. r and R n The proportional relationship between the refrigerant flow regulating valve 305 and the concentrated solution flow regulating valve 301 can guide the specific adjustment and control of these valves. Specifically, the mass flow rate R of the refrigerant flowing from the outlet of the refrigerant flow regulating valve 305 to the refrigeration subsystem can be determined first based on the external demand for the refrigeration capacity of the refrigeration subsystem. r Then according to R r and R n The proportional relationship between them is determined by R. nThis allows for the matched control and regulation of the two flow regulating valves.

[0078] Specifically, in this embodiment, R r and R n The proportional relationship between them is calculated based on the following conditions: the system is in a stable state (Note: the result measured when the solution system reaches the final equilibrium state); the solutions at the outlets of generator 302, first absorber 104 and second absorber 203 are all in the corresponding saturated state (i.e., the final equilibrium state); the flow pressure loss of the system pipeline and the heat loss to the external environment are ignored; the enthalpy values ​​of the solution and refrigerant before and after the throttling process are approximately considered unchanged; the refrigerant at the outlet of condenser 304 is in a saturated liquid state, and the refrigerant at the outlets of first evaporator 102 and second evaporator 202 is in a saturated gas state.

[0079] Based on these conditions, when the design temperature of the refrigerant outlet of the first evaporator 102 is determined, since the refrigerant is in a saturated gas state, the first pressure of the refrigerant at this location can be determined according to the refrigerant's temperature-pressure state diagram. Since the pressure on the first absorber 104 side is the same as the pressure on the evaporator side, the pressure in the first absorber 104 can be determined as the first pressure. Based on the first pressure of the first absorber 104 and the design temperature of the outlet, combined with the solution being in a corresponding saturated state and the temperature-pressure-concentration state diagram of the solution system, the solvent solubility X of the dilute solution 1 at the outlet of the first absorber 104 can be determined. w1 Similarly, based on the design temperature of the refrigerant at the outlet of the second evaporator 202, the design temperature of the dilute solution 2 at the outlet of the second absorber 203, and the corresponding saturation state diagrams of the refrigerant and dilute solution 2, the solvent concentration X of the dilute solution 2 at the outlet of the second absorber 203 can be determined. w2 The design temperature at the generator 302 outlet is the same as the design temperature of the refrigerant and the concentrated solution at the generator 302 outlet. Specifically, the pressure corresponding to the design condensation temperature of the refrigerant in the condenser (saturation pressure), combined with the compressor's compression ratio (e.g., 1.3), can be used to determine the pressure of generator 302. Based on the pressure of generator 302 and the design temperature of the concentrated solution at the generator 302 outlet, combined with the saturation state of the concentrated solution and the temperature-pressure-concentration state diagram of the solution system, the solvent solubility X of the concentrated solution at the generator 302 outlet can be determined. s .

[0080] That is, given the system's rated operating condition design parameters, X can be calculated and determined based on certain simplified setting conditions. s X w1 and X w2 The specific values ​​of the three, thus f(R) n ,R rSince R is a known constant, its value can be determined. r and R n The proportional relationship between the two flow control valves can serve as a guide for adjustment when the heat pump system regulates and controls the two flow control valves. Adjusting the two flow control valves according to this proportional relationship is beneficial for achieving the matching of refrigerant and concentrated solution, and for improving the stable and efficient operation performance of the system.

[0081] Specifically, R r and R n The specific derivation process of the formula for calculating the proportional relationship between them is as follows:

[0082] Let the total mass flow rate of the refrigerant at the outlet of the circulating condenser 304 be m. r The total mass flow rate of the concentrated solution at the outlet of generator 302 is m³ / s. s The temperature is T s The pressure is P s The solvent concentration is X s The mass flow rate of dilute solution 1 at the outlet of the first absorber 104 is m. w1 The temperature is T w1 The pressure is P w1 The solvent concentration is X w1 The mass flow rate of dilute solution 2 at the outlet of the second absorber 203 is m. w2 The temperature is T w2 The pressure is P w2 The solvent concentration is X w2 .

[0083] Now, let's assume two variables, a and b, where a represents the mass flow rate of dilute solution 1 required for a unit mass flow rate of refrigerant circulation within the refrigeration subsystem, and b represents the mass flow rate of dilute solution 2 required for a unit mass flow rate of refrigerant circulation within the heating subsystem. The expressions are as follows:

[0084]

[0085]

[0086] The mass conservation principle is satisfied within the first absorber 104:

[0087] m w1 =R r •m r +R n •m s (3)

[0088] Substituting a, we get:

[0089] a•m r •R r =Rr •m r +(a-1)•R r •m r (4)

[0090] Solvent conservation is satisfied within the first absorber 104:

[0091] a·m r •R r ·X w1 = (a-1)·R r ·m r ·X s (5)

[0092] According to the law of solvent conservation:

[0093]

[0094] Similarly, the mass conservation law is satisfied within the second absorber 203:

[0095] m w2 =(1-R) r )·m r +(1-R n )·m s (7)

[0096] Substituting b, we get:

[0097] b·m r ·(1-R r )=(1-R r )·m r +(b-1)·(1-R r )·m r (8)

[0098] Solvent conservation is satisfied within the second absorber 203:

[0099] b·m r ·(1-R r )·X w2 = (b-1)·(1-R) r )·m r ·X s (9)

[0100] According to the law of solvent conservation:

[0101]

[0102] As can be seen from formulas (6) and (10), both a and b have a certain functional relationship with the corresponding solution concentration. Through experimental data or fitting curves of the temperature-pressure-concentration equilibrium relationship in the solution system, the solution concentration at the set temperature and corresponding pressure can be obtained, thus calculating the values ​​of a and b, as shown in formulas (11) and (12).

[0103]

[0104]

[0105] Formula (3) can be transformed into:

[0106]

[0107] Similarly, formula (7) can be transformed into:

[0108]

[0109] From formulas (13) and (14), we can obtain:

[0110]

[0111] From formulas (6) and (10), it can be seen that the solution concentration X s X w1 and X w2 Given the given conditions, a and b can be calculated separately, and further, the description of R can be obtained. n and R r The function f(R) of the relation n ,R r The value of f(R) is given. Under the condition of maintaining a constant rated operating condition, with the set temperature and corresponding pressure remaining unchanged, and the solution concentration not changing significantly, the values ​​of a and b remain unchanged. At this time, the function f(R) is... n ,R r R is a certain value. n and R r The values ​​of satisfy the corresponding relationship. Therefore, under the premise of maintaining rated operating conditions, when the refrigerant flow regulating valve 305 is changed, that is, R is adjusted... r When taking a value, it is determined by the function f(R) n ,R r We can obtain R n The value of is used to adjust the concentrated solution flow regulating valve 301 accordingly.

[0112] See Figure 1This invention provides an absorption heat pump system, comprising a compression-assisted enhancement subsystem, a refrigeration subsystem, and a heating subsystem. It employs a novel working fluid pair with superior performance. The system absorbs heat energy provided by a driving heat source and outputs high-quality low-temperature chilled water and high-temperature hot water respectively through refrigerant phase change and solution absorption processes. The specific structure is as follows:

[0113] The compression-assisted enhancement subsystem includes a generator 302, a compressor 303, a condenser 304, a concentrated solution flow regulating valve 301, and a refrigerant flow regulating valve 305. The system's operating performance can be improved by adjusting the operation of the compressor 303. The generator 302 has its concentrated solution outlet connected to the concentrated solution flow regulating valve 301 via a pipeline, and its refrigerant vapor outlet connected to the compressor 303 inlet. The compressor 303 outlet is connected to the refrigerant inlet of the condenser 304 via a pipeline, and the condenser 304's refrigerant outlet is connected to the refrigerant flow regulating valve 305. The refrigeration and heating subsystems can operate independently or in parallel through refrigerant and solution flow regulation. This invention enables heat recovery and the production of high-quality cold and heat energy through solution circulation.

[0114] This invention can efficiently recover low-grade heat energy below 80°C. Under the condition of parallel operation of the refrigeration subsystem and the heating subsystem, it can produce low-temperature chilled water (near 10°C) and high-temperature (near 70°C) hot water respectively. It can supply high-quality cold energy and high-quality heat energy with a temperature higher than the driving heat source temperature. At the same time, by means of a flow regulating valve, the flow ratio of refrigerant and concentrated solution in the refrigeration subsystem and the heating subsystem can be changed, thereby controlling the ratio of system refrigeration and heating to meet the supply needs of different levels of cold energy and heat energy.

[0115] This invention adds a compressor 303 between the generator 302 and the condenser 304. By changing the degree of refrigerant compression, the pressure ratio between the medium-pressure side generator 302 and the high-pressure side condenser 304 can be adjusted, controlling the concentration difference between the concentrated solution and the dilute solution of the refrigeration subsystem and the heating subsystem. When the temperature of the driving heat source is low, the pressure difference between the medium-pressure side generator 302 and the high-pressure side condenser 304 can be increased by increasing the degree of compression, thereby reducing the pressure requirement of the generation process in the generator 302, which is beneficial to the stable operation of the generation process and maintains or improves the operating performance of the system.

[0116] To more clearly illustrate the operation and adjustment method of the absorption heat pump system of the present invention, the working process of the absorption heat pump system will be further described in the following specific embodiments:

[0117] See Figure 2 The present invention provides an absorption heat pump system that can recover low-grade heat energy at temperatures below 80°C. One of its operating processes is as follows:

[0118] This invention can achieve simultaneous and parallel operation of cooling and heating. Taking a driving heat source temperature of 65°C as an example, the recovered heat source provides driving energy to the generator 302 through heat exchange, reducing the heat source temperature to 55°C. The temperature of the concentrated solution and refrigerant vapor formed during the generation process is 52°C. The concentrated solution passes through the concentrated solution flow regulating valve 301, and is distributed at a flow ratio R. n and 1-R n The refrigerant vapor generated flows into the compressor 303, which is connected to the refrigeration and heating subsystems. The pressure ratio between the condenser and generator is adjusted by setting the compression level; taking a pressure ratio of 1.5 as an example, the pressure of the refrigerant vapor exiting the compressor 303 increases, and the temperature can rise to 70°C. It then re-enters the generator 302, where it is cooled through heat exchange and flows to the condenser 304 at a temperature of 55°C. In the condenser 304, cooling water with an initial temperature of 23°C, supplied from outside the system, cools and condenses the refrigerant vapor. After heat exchange, the temperature of the cooling water rises to 28°C, and the refrigerant condenses into a liquid at 30°C before exiting the condenser 304. It then flows through the refrigerant flow regulating valve 305 at a flow rate ratio R... r and 1-R r The flow is directed to the refrigeration subsystem and the heating subsystem, where R is set. r The refrigerant ratio is 70%, and correspondingly, 30% of the refrigerant flows to the heating subsystem. Calculations show that when R... r When the concentration is 70%, the proportion R of the concentrated solution flowing to the refrigeration subsystem is... n Approximately 78%, meaning that after passing through the concentrated solution flow regulating valve 301, 78% of the concentrated solution flows to the first solution heat exchanger 106 of the refrigeration subsystem, and 22% of the concentrated solution flows to the second solution pump 205 of the heating subsystem.

[0119] The ratio is R r The refrigerant flows to the refrigeration subsystem, and after being depressurized by the refrigerant throttle valve 101, it flows into the first evaporator 102. It absorbs the heat energy from the chilled water with a temperature of 20°C input from outside the system and undergoes evaporation. After cooling, the temperature of the chilled water drops to 13°C, and it outputs high-quality cold energy. The refrigerant vapor formed by evaporation with a temperature of 10°C flows to the first absorber 104. The concentrated solution in the first absorber 104 absorbs the refrigerant vapor and releases heat. It absorbs heat energy through the cooling water with a temperature of 23°C input from outside the system. After heat exchange, the temperature of the cooling water rises to 28°C, and the temperature of the resulting dilute solution 1 is 30°C. It then flows to the first solution pump 103. In the first solution heat exchanger 106, the high-temperature concentrated solution and the low-temperature dilute solution 1 undergo countercurrent heat exchange, which can improve the energy utilization rate of the system. Then, the dilute solution 1 flows into the generator 302.

[0120] The ratio is 1-R rThe refrigerant flows to the heating subsystem and is pumped by the refrigerant pump 201 to the second evaporator 202. The heat energy input from outside the system at a temperature of 65°C can provide the driving heat source. The refrigerant evaporates and forms refrigerant vapor at a temperature of 55°C. The temperature of the driving heat source drops to 55°C, and the refrigerant vapor flows into the second absorber 203. The absorption process in the second absorber 203 releases a large amount of heat energy, which heats the hot water input from outside the system at a temperature of 50°C. The hot water is heated to 70°C and supplies high-quality heat energy to the outside. The dilute solution 2 formed during the absorption process has a temperature of 73°C. It undergoes countercurrent heat exchange with the low-temperature concentrated solution from the second solution pump 205 through the second solution heat exchanger 204, which improves the energy utilization efficiency of the heating subsystem. Finally, the dilute solution 2 flows into the generator 302 through the dilute solution throttle valve 206.

[0121] In general, in the above specific embodiments, the generator 302 and the second evaporator 202 can recover the heat energy of a heat source at a temperature of 65°C to drive the system operation, and the heat recovery reduces the temperature of the heat source to 55°C. In addition, chilled water at a temperature of 13°C can be produced through the evaporation of the first evaporator 102, and hot water at a temperature of 70°C can be produced through the absorption process of the second absorber 203. Both supply high-quality cold energy and hot energy to the outside, thereby realizing the recovery of low-temperature, i.e., low-grade heat energy and applying the heat energy to the cooling and heating modules, thus broadening the application environment and scenarios of absorption heat pump technology and related systems.

[0122] The absorption heat pump system provided by this invention can also achieve two different working processes: cooling only and heating only, as follows:

[0123] See Figure 3 While retaining the original components and structure, this invention adjusts the opening degree of the refrigerant flow regulating valve 305 and the concentrated solution flow regulating valve 301, so that the proportion R of the refrigerant flow to the refrigeration subsystem is increased. r The value is 1, meaning that the refrigerant does not flow to the heating subsystem. Correspondingly, the proportion of concentrated solution flow to the refrigeration subsystem is R. n Adjusted to 1; the generator 302 recovers the heat energy of a heat source at a temperature of 65°C to drive the system operation, and the temperature of the heat source drops to 55°C. Through the evaporation of the first evaporator 102, chilled water at a temperature of 13°C can be produced to supply high-quality cold energy to the outside, and the recovered heat energy is fully applied to the refrigeration module.

[0124] See Figure 4 Retaining the original components and structure, this invention further adjusts the opening degrees of the refrigerant flow regulating valve 305 and the concentrated solution flow regulating valve 301, so that the proportion R of the refrigerant flow to the refrigeration subsystem is adjusted. r The value is 0, meaning the refrigerant flows entirely to the heating subsystem. Correspondingly, the proportion of concentrated solution flowing to the heating subsystem is adjusted to 1 (R).n =0); The generator 302 and the second evaporator 202 respectively recover the heat energy of the heat source at a temperature of 65°C to drive the system to run. The absorption process of the second absorber 203 can produce hot water at a temperature of 70°C. The recovered heat energy is fully applied to the heating module.

[0125] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method for an absorption heat pump system, characterized in that, The absorption heat pump system includes a generator, a compressor, a condenser, and a refrigeration subsystem. The generator is used to evaporate the refrigerant with a working fluid to form a gaseous refrigerant and a concentrated solution. The gas outlet of the generator is connected to the inlet of the compressor, and the outlet of the compressor is connected to the inlet of the condenser. The refrigeration subsystem includes a refrigerant throttling valve, a first evaporator, and a first absorber connected in sequence. The outlet of the condenser is connected to the inlet of the refrigerant throttling valve, the outlet of the first absorber is connected to the inlet of the generator, and the liquid outlet of the generator is connected to the inlet of the first absorber. The first evaporator is used to provide cooling capacity. The absorption heat pump system also includes a heating subsystem, which comprises a refrigerant pump, a second evaporator, and a second absorber connected in sequence. The condenser outlet is connected to a refrigerant flow regulating valve, which is connected to the refrigerant throttling valve and the refrigerant pump, respectively. The generator liquid outlet is connected to a concentrated solution flow regulating valve, which is connected to the first absorber and the second absorber, respectively. The outlet of the second absorber is connected to the inlet of the generator. The second absorber is used to provide heat. The control method includes: The compression degree of the compressor is adjusted according to the temperature of the driving heat source. As the temperature of the driving heat source decreases, the compression degree of the compressor is gradually increased. The control method further includes: Design the rated operating conditions of the system; Based on the rated operating conditions of the system, determine the adjustment ratio between the refrigerant flow regulating valve and the concentrated solution flow regulating valve; The refrigerant flow regulating valve and the concentrated solution flow regulating valve are adjusted and controlled according to the adjustment ratio. The refrigerant flow regulating valve and the concentrated solution flow regulating valve shall be adjusted and controlled according to the following proportional relationship: ； ； ； Among them, R r R represents the proportion of the refrigerant mass flow rate from the outlet of the refrigerant flow regulating valve to the refrigeration subsystem. n The proportion of the mass flow rate of the concentrated solution flowing from the outlet of the concentrated solution flow regulating valve to the refrigeration subsystem; X s The solvent concentration of the concentrated solution at the liquid outlet of the generator; X w1 The solvent concentration of the dilute solution at the outlet of the first absorber; X w2 The solvent concentration of the dilute solution at the outlet of the second absorber; X s , X w1 and X w2 The design parameters are determined based on the rated operating conditions of the system.

2. The control method for an absorption heat pump system as described in claim 1, characterized in that, The liquid outlet of the generator is connected to the first absorber via a concentrated solution throttling valve, and the outlet of the first absorber is connected to the generator via a first solution pump.

3. The control method for an absorption heat pump system as described in claim 1, characterized in that, The refrigeration subsystem further includes a first solution heat exchanger. The liquid outlet of the generator flows through a first process of the first solution heat exchanger and then into the first absorber. The outlet of the first absorber flows through a second process of the first solution heat exchanger and then into the generator.

4. The control method for an absorption heat pump system as described in claim 1, characterized in that, The liquid outlet of the generator is connected to the second absorber via a second solution pump, and the outlet of the second absorber is connected to the inlet of the generator via a dilute solution throttling valve.

5. The control method for an absorption heat pump system as described in claim 1, characterized in that, The heating subsystem further includes a second solution heat exchanger. The liquid outlet of the generator flows through the first process of the second solution heat exchanger and then into the second absorber. The outlet of the second absorber flows through the second process of the second solution heat exchanger and then into the generator.

6. The control method for an absorption heat pump system as described in claim 1, characterized in that, The first evaporator and the second evaporator each include a shell and a heat exchange tube disposed inside the shell. The shell is provided with a refrigerant inlet and an outlet, and one end of a spray pipe is connected to the bottom of the shell. The other end of the spray pipe extends from the top of the shell into the interior of the shell.

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