Multistage air-supplementing jet high-temperature heat pump system, control method and heat exchange system thereof

Abstract

The application relates to the technical field of heat pump energy-saving, in particular to a multistage air supplementing jet type high-temperature heat pump system, a control method thereof and a heat exchange system, wherein the heat pump system comprises a multistage air supplementing compressor, a first liquid distribution condenser, a first throttling valve, a flash tank, a first ejector, a second throttling valve and a gas distribution evaporator; the outlet of the multistage air supplementing compressor is communicated with the inlet of the first liquid distribution condenser; one outlet of the first liquid distribution condenser is communicated with the inlet of the flash tank through the first throttling valve, and the other outlet is communicated with the inlet of the gas distribution evaporator through the second throttling valve; one outlet of the flash tank, the outlet of the first ejector and one outlet of the gas distribution evaporator are respectively communicated with different inlets of the multistage air supplementing compressor; the other outlet of the flash tank is communicated with one inlet of the first ejector; and the other outlet of the gas distribution evaporator is communicated with the other inlet of the first ejector. The application can greatly reduce the irreversible loss of the heat exchange process and significantly improve the energy utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of heat pump energy-saving technology, and more specifically, to a multi-stage injection high-temperature heat pump system and its control method and heat exchange system. Background Technology

[0002] Heat pump systems, as a highly efficient and environmentally friendly technology, are widely used in waste heat recovery, space heating, and hot water production. To further expand the applicability of heat pump systems, the application scenarios and temperature rise requirements will become more complex. High-temperature heat pump systems with large temperature rises not only conform to the trend of heat pump technology developing towards higher temperature ranges, but also utilize lower-grade heat energy, making them a low-carbon and energy-saving technology that aligns with the current era.

[0003] Applying non-azeotropic working fluids to heat pump systems can leverage their temperature glide during phase change to reduce the average heat transfer temperature difference and improve energy efficiency. However, for complex heat usage scenarios, the fixed composition and constant temperature glide of non-azeotropic working fluids cannot be adjusted according to heat demand, leading to deteriorated heat transfer performance. During condensation, the working fluid transforms from a gaseous phase to a liquid phase; as dryness decreases, the liquid film thickness continuously increases, resulting in reduced heat transfer efficiency. During evaporation, the heat transfer coefficient of the working fluid initially increases and then decreases with increasing dryness, exhibiting significant fluctuations. Therefore, expanding the applicable temperature range of heat pump systems, reducing irreversible losses in the heat transfer process, and improving the performance of heat pump systems are the main research directions for those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-stage air-injection high-temperature heat pump system that adopts a segmented heat exchange matching method, which can significantly reduce irreversible losses in the heat exchange process and significantly improve energy utilization efficiency.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A multi-stage gas-injection high-temperature heat pump system is provided, including a multi-stage gas-injection compressor, a first liquid-liquid separator, a first throttling valve, a flash tank, a first ejector, a second throttling valve, and a gas-injection evaporator;

[0007] The outlet of the multi-stage gas-injection compressor is connected to the inlet of the first liquid-liquid separator; one outlet of the first liquid-liquid separator is connected to the inlet of the flash tank through a first throttle valve, and the other outlet of the first liquid-liquid separator is connected to the inlet of the gas-distribution evaporator through a second throttle valve; one outlet of the flash tank, the outlet of the first ejector, and one outlet of the gas-distribution evaporator are respectively connected to different inlets of the multi-stage gas-injection compressor; the other outlet of the flash tank is connected to one inlet of the first ejector; and the other outlet of the gas-distribution evaporator is connected to the other inlet of the first ejector.

[0008] The multi-stage injection-type high-temperature heat pump system of this invention utilizes the temperature glide characteristics of a non-azeotropic working fluid to reduce irreversible heat exchange losses. It achieves component control within the heat exchanger through a liquid-liquid condenser and a gas-distribution evaporator, and global control of the working fluid composition of the thermodynamic system through ejectors and a flash tank. By changing the working fluid composition and adjusting its temperature glide, better heat exchange matching is achieved, improving system efficiency. Furthermore, the ejector saves power consumption during the compression process, and the intermediate injection during multi-stage compression enables intermediate cooling, effectively reducing the compressor exhaust temperature and improving system performance. For the heat exchange process, since gas-liquid separation exists within both the liquid-liquid condenser and the gas-distribution evaporator, the dryness of the heat exchange process can be controlled, maintaining a high heat transfer coefficient and thus increasing the heat exchanger's capacity. The terms "first," "second," and "third" in this document are only used to distinguish components in different locations; for example, "first throttle valve" and "second throttle valve" both represent throttle valves, differing only in location, while their structure and function can be the same.

[0009] Preferably, the inlet of the multi-stage gas-injection compressor includes at least a multi-stage gas-injection compressor inlet, a first gas-injection port, and a second gas-injection port, the outlet of the first injector is connected to the first gas-injection port, and one of the outlets of the flash tank is connected to the second gas-injection port.

[0010] Preferably, it further includes a high-pressure evaporator, and the outlet of the first injector is connected to the first air supply port through the high-pressure evaporator.

[0011] Preferably, the system further includes a second liquid-liquid condenser, a second ejector, a third throttling valve, and a high-pressure compressor. The outlet of the multi-stage gas-fuel compressor is divided into two paths: one path connects to the inlet of the first liquid-liquid condenser via the high-pressure compressor, and the other path connects to the inlet of the second liquid-liquid condenser via the second ejector. One outlet of the second liquid-liquid condenser connects to the inlet of the flash tank via the first throttling valve, and the other outlet connects to the inlet of the gas-distributing evaporator via the third throttling valve. For high-temperature-rise heating demands, segmented heat exchange matching using the first and second liquid-liquid condensers can significantly reduce irreversible losses in the heat exchange process and substantially improve energy utilization efficiency.

[0012] Preferably, the first liquid-distributing condenser includes a condensing manifold, multiple condensing heat exchange tubes, a condensing liquid-distributing pipe, and a liquid-distributing baffle. The liquid-distributing baffle is provided with multiple liquid-distributing holes. The liquid-distributing baffle is installed in the condensing manifold. The multiple condensing heat exchange tubes are arranged sequentially and interconnected with each other and are all connected to the condensing manifold. The condensing liquid-distributing pipe is also connected to the condensing manifold. The inlet of the condensing manifold is connected to the outlet of the multi-stage gas injection compressor. The outlet of the condensing manifold is connected to the inlet of the second throttling valve. The condensing liquid-distributing pipe is connected to the inlet of the flash tank through the first throttling valve.

[0013] Preferably, the gas-distributing evaporator includes an evaporation header, multiple evaporation heat exchange tubes, an evaporation gas distribution pipe, and an evaporation baffle. The evaporation baffle is located in the evaporation header. The multiple evaporation heat exchange tubes are arranged sequentially and interconnected with each other and are all connected to the evaporation header. The evaporation gas distribution pipe is also connected to the evaporation header. The inlet of the evaporation header is connected to the outlet of the second throttle valve. The outlet of the evaporation header is connected to the inlet of the multi-stage gas supply compressor. The evaporation gas distribution pipe is connected to one of the inlets of the first injector.

[0014] Preferably, the inlet of the first injector is divided into an ejector inlet and an ejected inlet. The ejector inlet is connected to the liquid phase outlet of the flash tank, and the ejected inlet is connected to the gas distribution outlet of the gas separator evaporator.

[0015] Preferably, the working pressure of the ejector inlet is greater than the working pressure of the ejected inlet.

[0016] The present invention also provides a heat exchange system, including the multi-stage injection high-temperature heat pump system, the heat sink side heat exchange module, and the heat source side heat exchange module as described above. The heat sink side heat exchange module is connected in sequence to the second liquid separator and the first liquid separator, and the heat source side heat exchange module is connected in sequence to the high-pressure evaporator and the gas separator evaporator.

[0017] This invention also provides a control method for a multi-stage injection high-temperature heat pump system, applied to the multi-stage injection high-temperature heat pump system described above, and operates as follows:

[0018] The working pressures of the first liquid separator condenser, the second liquid separator condenser, the second ejector, the multi-stage gas supply compressor, the flash tank, the first ejector, the high-pressure evaporator, and the gas-distributing evaporator are controlled and classified into pressure levels. The working pressure of the first liquid separator condenser is defined as level six, the working pressures of the second liquid separator condenser and the second ejector are level five, the outlet pressure of the multi-stage gas supply compressor is level four, the working pressure of the flash tank is level three, the working pressures of the first ejector and the high-pressure evaporator are level two, and the working pressure of the gas-distributing evaporator is level one. The working pressures of each part meet the following condition: level six pressure > level five pressure > level four pressure > level three pressure > level two pressure > level one pressure.

[0019] Control the liquid flow rate of the first liquid separator and the second liquid separator, the gas flow rate of the gas separator evaporator, and the branch flow rate from the multi-stage gas compressor to the second injector, and ensure that the liquid flow rate of the first liquid separator is less than the main flow rate of the first liquid separator, the liquid flow rate of the second liquid separator is less than the main flow rate of the second liquid separator, the gas flow rate of the gas separator evaporator is less than the main flow rate of the gas separator evaporator, and the branch flow rate from the multi-stage gas compressor to the second injector is less than the branch flow rate from the multi-stage gas compressor to the first liquid separator.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention utilizes the temperature glide characteristics of non-azeotropic working fluids to reduce irreversible heat exchange losses. It achieves component control within the heat exchanger through a liquid-liquid condenser and a gas-distribution evaporator, and global control of the working fluid composition using ejectors and flash tanks. By changing the working fluid composition and adjusting its temperature glide, better heat exchange matching is achieved, improving system efficiency. Furthermore, the ejector saves power consumption during compression, and intermediate gas injection during multi-stage compression enables intermediate cooling, effectively reducing compressor exhaust temperature and improving system performance. For the heat exchange process, the gas-liquid separation within the liquid-liquid condenser and gas-distribution evaporator allows for control of the dryness of the heat exchanger, maintaining a high heat transfer coefficient and thus increasing the heat exchange capacity. For high-temperature-rise heat demands, the segmented heat exchange matching method significantly reduces irreversible heat exchange losses and substantially improves energy efficiency. This system is an energy-saving, economical, environmentally friendly, and highly efficient improvement solution that effectively enhances the performance of heat pump cycle systems, promotes low-carbon and energy-saving technologies in heat pump systems, and drives the development of heat pump technology towards higher temperature ranges. Attached Figure Description

[0022] Figure 1This is a schematic diagram of the structure of a multi-stage air-injection high-temperature heat pump system according to Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of a multi-stage air-injection high-temperature heat pump system according to Embodiment 3 of the present invention;

[0024] Figure 3 This is a schematic diagram of the working fluid composition of Embodiment 3 of the multi-stage gas injection high-temperature heat pump system of the present invention;

[0025] Figure 4 This is a schematic diagram of the liquid separator condenser of a multi-stage gas injection high-temperature heat pump system according to the present invention.

[0026] Figure 5 This is a schematic diagram of the condensate separator outlet of a multi-stage air-injection high-temperature heat pump system according to the present invention.

[0027] Figure 6 This is a schematic diagram of the structure of the gas separator evaporator of a multi-stage gas injection high-temperature heat pump system according to the present invention;

[0028] Figure 7 This is a schematic diagram of the evaporator gas outlet of a multi-stage injection high-temperature heat pump system according to the present invention.

[0029] Figure 8 This is a schematic diagram of the structure of a multi-stage gas-injection compressor in a multi-stage gas-injection high-temperature heat pump system according to the present invention;

[0030] Figure 9 This is a schematic diagram of the segmented heat exchange matching of a multi-stage air-injection high-temperature heat pump system according to the present invention.

[0031] The markings in the diagram are explained below:

[0032] 101. Multistage gas-injection compressor; 1011. Inlet of multistage gas-injection compressor; 1012. Outlet of multistage gas-injection compressor; 1013. First gas-injection port; 1014. Second gas-injection port; 102. High-pressure compressor; 103. First liquid-liquid separator; 1031. Condensation heat exchange tube; 1032. Condensation header; 1033. Condensation liquid-liquid separator; 1034. Liquid-liquid separator baffle; 1035. Liquid-liquid separator orifice; 104. Second throttle valve; 105. Three-stage throttle valve; 106. Gas-distributing evaporator; 1061. Evaporation heat exchange tube; 1062. Evaporation header; 1063. Evaporation gas distribution pipe; 1064. Evaporation baffle; 107. Second ejector; 108. Second liquid-distributing condenser; 109. First throttle valve; 110. Flash tank; 111. First ejector; 112. High-pressure evaporator; 113. Heat exchange module on the heat sink side; 114. Heat exchange module on the heat source side; a~r represent different positions; x 1~ x13 These represent different working fluid components. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0039] Example 1

[0040] like Figure 1 The diagram shows a first embodiment of a multi-stage injector high-temperature heat pump system according to the present invention, comprising a multi-stage injector compressor 101, a first liquid-liquid separator 103, a first throttle valve 109, a flash tank 110, a first ejector 111, a second throttle valve 104, and a gas-distribution evaporator 106; the outlet of the multi-stage injector compressor 101 is connected to the inlet of the first liquid-liquid separator 103; one outlet of the first liquid-liquid separator 103 is connected to the inlet of the flash tank 110 through the first throttle valve 109, and the other outlet of the first liquid-liquid separator 103 is connected to the inlet of the flash tank 110 through the second throttle valve 104. Valve 104 is connected to the inlet of the gas separator evaporator 106; one outlet of flash tank 110 is connected to one inlet of the first injector 111, and one outlet of gas separator 106 is connected to the other inlet of the first injector 111; the other outlet of flash tank 110 is connected to one inlet of the multi-stage gas compressor 101, and the outlet of the first injector 111 is connected to the other inlet of the multi-stage gas compressor 101; the other outlet of gas separator evaporator 106 is connected to another inlet of the multi-stage gas compressor 101 that is different from the above two inlets.

[0041] The first liquid-liquid separator condenser 103 has two heat exchange fluids, namely the working fluid side and the heat sink side. The working fluid refers to the medium through which thermal energy and mechanical energy are converted into each other. Figure 1The diagram shows the connection relationship on the working fluid side of this invention; the heat sink side refers to the heat exchange system that exchanges heat with the working fluid side, and is used for heat exchange with the separatory condenser itself. Figure 1 The diagram is not shown. The outlet of the first liquid-liquid condenser 103 on the working fluid side is divided into two paths. One path, the liquid outlet of the first liquid-liquid condenser 103, flows through the first throttle valve 109 and connects to the inlet of the flash tank 110. The other path, the outlet of the first liquid-liquid condenser 103, flows through the second throttle valve 104 and connects to the inlet of the gas-distributing evaporator 106. The gas-distributing evaporator 106 has two heat exchange fluids, one on the working fluid side and one on the heat source side. The heat source side here is similar to the heat sink side mentioned earlier, also serving as a heat exchange system. The outlet of the working fluid side of the gas-distributing evaporator 106 is divided into two paths. One path, the gas outlet of the gas-distributing evaporator 106, connects to the ejected inlet of the first ejector 111. The other path, the outlet of the gas-distributing evaporator 106, connects to the inlet 1011 of the multi-stage make-up gas compressor. The outlet 1012 of the multi-stage make-up gas compressor is connected to the inlet of the first liquid-liquid condenser 103. The gas phase outlet of the flash tank 110 is connected to the second gas supply port 1014 of the multi-stage gas supply compressor 101, the liquid phase outlet of the flash tank 110 is connected to the ejector inlet of the first ejector 111, and the outlet of the first ejector 111 is connected to the first gas supply port 1013 of the multi-stage gas supply compressor 101.

[0042] In this embodiment, the working fluid is a non-azeotropic mixture, which is composed of a high-boiling-point working fluid and a low-boiling-point working fluid mixed in a certain proportion. The heat pump system uses a non-azeotropic working fluid for circulation, and by matching the temperature glide of the non-azeotropic working fluid with the heat exchange process, irreversible losses during circulation can be reduced. This invention utilizes the first ejector 111 and the flash tank 110 to achieve global control of the working fluid composition of the thermodynamic system, saving power consumed during compression, achieving intermediate cooling during compression, effectively reducing the compressor exhaust temperature, and improving system operating performance.

[0043] In one embodiment of the present invention, the first liquid-distributing condenser 103 includes a condensing manifold 1032, multiple condensing heat exchange tubes 1031, a condensing liquid-distributing pipe 1033, and a liquid-distributing baffle 1034. The liquid-distributing baffle 1034 is provided with multiple liquid-distributing holes 1035. The liquid-distributing baffle 1034 is installed in the condensing manifold 1032. The multiple condensing heat exchange tubes 1031 are arranged sequentially and interconnected with each other and are all connected to the condensing manifold 1032. The condensing liquid-distributing pipe 1033 is also connected to the condensing manifold 1032. The inlet of the condensing manifold 1032 is connected to the outlet 1012 of the multi-stage gas injection compressor. The outlet of the condensing manifold 1032 is connected to the inlet of the second throttle valve 104. The condensing liquid-distributing pipe 1033 is connected to the inlet of the flash tank 110 through the first throttle valve 109.

[0044] By reasonably adjusting the size and number of the liquid distribution holes 1035 on the liquid distribution baffle 1034 and the diameter of the condenser liquid distribution pipe 1033, the composition and flow rate of the working fluid at the liquid distribution outlet can be controlled, thereby changing the composition of the remaining working fluid in the liquid distribution condenser, altering its thermophysical parameters, controlling its temperature glide, reducing the irreversible heat exchange loss of the liquid distribution condenser, and increasing the dryness of the remaining working fluid, thus enhancing the heat exchange capacity of the liquid distribution condenser.

[0045] In one embodiment of the present invention, the gas-distributing evaporator 106 includes an evaporation manifold 1062, multiple evaporation heat exchange tubes 1061, an evaporation gas distribution pipe 1063, and an evaporation baffle 1064. The evaporation baffle 1064 is disposed in the evaporation manifold 1062. The multiple evaporation heat exchange tubes 1061 are arranged sequentially and interconnected with each other and are all connected to the evaporation manifold 1062. The evaporation gas distribution pipe 1063 is also connected to the evaporation manifold 1062. The inlet of the evaporation manifold 1062 is connected to the outlet of the second throttle valve 104. The outlet of the evaporation manifold 1062 is connected to the inlet 1011 of the multi-stage gas supply compressor. The evaporation gas distribution pipe 1063 is connected to one of the inlets of the first injector 111.

[0046] By rationally designing the diameter of the evaporation gas distribution pipe 1063, the composition and flow rate of the working fluid at the evaporation gas distribution outlet can be adjusted, thereby changing the composition of the remaining working fluid in the gas distribution evaporator 106, altering its thermophysical parameters, regulating its temperature glide, reducing the irreversible heat exchange loss of the gas distribution evaporator 106, and simultaneously enabling the working fluid to evaporate at a higher heat transfer coefficient, thus improving the heat exchange efficiency of the gas distribution evaporator 106.

[0047] Example 2

[0048] The following is a second embodiment of a multi-stage gas-injection high-temperature heat pump system according to the present invention. This embodiment is similar to embodiment 1, except that it also includes a high-pressure evaporator 112. The outlet of the first injector 111 is connected to the first gas injection port 1013 of the multi-stage gas-injection compressor 101 through the high-pressure evaporator 112. The high-pressure evaporator 112 is located between the first injector 111 and the multi-stage gas-injection compressor 101. The high-pressure evaporator 112 has two heat exchange fluids, namely the working fluid side and the heat source side. The outlet of the working fluid side is connected to the first gas injection port 1013 of the multi-stage gas-injection compressor 101. The high-pressure evaporator 112 has the following functions: First, it can make the gas-liquid two-phase working fluid at the outlet of the first injector 111 absorb heat and transform into a gas phase, which then enters the multi-stage gas-injection compressor 101 through the first gas injection port 1013. The advantage is that it avoids liquid compression during the compression process and reduces the superheat of the compressor exhaust. Secondly, it can form a dual-temperature (pressure) evaporation system with the gas separator evaporator 106, further matching the temperature changes of the working fluid and the heat source through stepped heat exchange, achieving a larger temperature range. The evaporation process absorbs heat, causing the temperature of the heat source to decrease in steps, achieving a greater degree of temperature drop.

[0049] Example 3

[0050] like Figures 2 to 9 The following is a third embodiment of a multi-stage gas-injection high-temperature heat pump system according to the present invention. This embodiment is similar to embodiment 2, except that it also includes a second liquid-distributing condenser 108, a second ejector 107, a third throttle valve 105, and a high-pressure compressor 102. The outlet of the multi-stage gas-injection compressor 101 is divided into two paths. One path is connected to the inlet of the first liquid-distributing condenser 103 through the high-pressure compressor 102. The other path of the outlet of the multi-stage gas-injection compressor 101 is connected to the inlet of the second liquid-distributing condenser 108 through the second ejector 107. One outlet of the second liquid-distributing condenser 108 is connected to the inlet of the flash tank 110 through the first throttle valve 109, and the other outlet of the second liquid-distributing condenser 108 is connected to the inlet of the gas-distributing evaporator 106 through the third throttle valve 105.

[0051] The multi-stage gas-injection high-temperature heat pump system in this embodiment can also be applied to scenarios with large temperature rises. The second ejector 107 is located between and connected to the first liquid-liquid condenser 103 and the second liquid-liquid condenser 108. The second ejector 107 is also connected to the outlet 1012 of the multi-stage gas-injection compressor. The second liquid-liquid condenser 108 has two heat exchange fluids, one on the working fluid side and one on the heat sink side. The outlet on the working fluid side of the second liquid-liquid condenser 108 is divided into two paths: one path connects the liquid-liquid outlet of the second liquid-liquid condenser 108 to the inlet of the flash tank 110 via the first throttle valve 109, and the other path connects the outlet of the second liquid-liquid condenser 108 to the inlet of the third throttle valve 105.

[0052] The high-pressure compressor 102 has the following functions: First, it is designed to achieve a difference in operating pressure between the first liquid separator 103 and the second liquid separator 108, thus enabling dual-temperature (pressure) condensation. Through stepped heat exchange, it further matches the temperature changes of the working fluid and the heat sink, achieving a wider temperature range. The condensation process releases heat, causing the heat sink temperature to rise in stages, achieving a greater temperature increase. Second, the high-pressure compressor 102, together with the first liquid separator 103 and the second ejector 107, allows for flexible adjustment of the composition of the circulating working fluid.

[0053] In this embodiment, the first liquid-distributing condenser 103 has two outlets: the liquid-distributing outlet of the first liquid-distributing condenser 103 and the outlet of the first liquid-distributing condenser 103. A saturated liquid working medium can be obtained from the liquid-distributing outlet of the first liquid-distributing condenser 103. The outlet of the first liquid-distributing condenser 103 is on the opposite side to the inlet of the first liquid-distributing condenser 103, and the liquid-distributing working medium exiting from the outlet of the first liquid-distributing condenser 103 is subcooled. The first liquid-distributing condenser 103 can have multiple liquid-distributing outlets, which are additional liquid-distributing ports added between the inlet and outlet of the first liquid-distributing condenser 103. The second liquid-distributing condenser 108 has two outlets: the liquid-distributing outlet of the second liquid-distributing condenser 108 and the outlet of the second liquid-distributing condenser 108. The liquid-distributing outlet of the second liquid-distributing condenser 108 is configured similarly to the liquid-distributing outlet of the first liquid-distributing condenser 103, and the outlet of the second liquid-distributing condenser 108 is also configured similarly to the outlet of the first liquid-distributing condenser 103. By rationally adjusting the composition and flow rate of the working fluid and increasing the dryness of the remaining working fluid, it has better heat exchange capacity compared with ordinary condensers.

[0054] like Figure 3 The diagram shown illustrates the working fluid composition of a multi-stage injection-type high-temperature heat pump system provided in an embodiment of the present invention. The working fluid composition at the outlet of the gas separator evaporator 106 is... x 1. The working fluid composition after mixing at the inlet 1011 of the multi-stage gas compressor and the first gas inlet 1013 is as follows: x 2. The working fluid composition at the outlet 1012 of the multi-stage gas compressor is as follows: x 3. The working fluid composition at the outlet of the first separatory condenser 103 is: x 4. The working fluid composition at the outlet of the third throttle valve 105 is as follows: x 5. The working fluid composition at the liquid outlet of the first liquid separator 103 is: x 6. The working fluid composition at the outlet of the second injector 107 is: x 7. The working fluid composition at the outlet of the second separatory condenser 108 is: x 8. The working fluid composition at the outlet of the second separator / condenser 108 is: x 9. The working fluid composition at the gas phase outlet of flash tank 110 is as follows: x 10 The working fluid composition at the liquid phase outlet of flash tank 110 is: x 11 The working fluid composition at the outlet of the gas separator 106 is as follows: x 12 The working fluid composition at the outlet of the first injector 111 is: x 13 .in x 1~ x 13 They represent different working fluid components.

[0055] like Figure 9 As shown, if it's a single heat exchange and the working fluid composition doesn't change, then the working fluid temperature change is equivalent to the outer dashed line. However, through gradient heat exchange and changes in composition during the heat exchange process, the working fluid temperature change curve will change. The area enclosed by the working fluid temperature line and the heat sink / source temperature line represents the irreversible loss in the heat exchange process; the larger the area, the greater the irreversible loss, and the lower the system operating efficiency. The line between the working fluid temperature line and the heat sink / source temperature line, parallel to the heat sink / source temperature line, represents the ideal temperature change curve of the working fluid under the minimum heat exchange temperature difference. The area enclosed by this line and the heat sink / source temperature line represents the unavoidable heat loss, which is the most ideal heat exchange situation. D,pinch This refers to the unavoidable heat exchange process losses described earlier, E D,fluid These are the avoidable heat exchange process losses; the sum of these two is the total heat exchange process loss. For different heat exchange processes, E... D,fluid The smaller the value, the better the temperature matching in the heat exchange process, and the less energy loss. In summary, by using gradient heat transfer and component control, energy loss in the heat exchange process can be reduced, and the energy utilization efficiency of the system can be improved.

[0056] The principle of this invention: The high-temperature and high-pressure gaseous working fluid (point e in the figure) enters the first liquid separator condenser 103 from the outlet of the high-pressure compressor 102 and is partially condensed. The liquid working fluid that has been condensed is separated from the liquid outlet of the first liquid separator condenser 103 and enters the injection inlet of the first ejector 111 (point i in the figure). Part of the gaseous working fluid at the outlet 1012 of the multi-stage gas-supply compressor enters the injection inlet of the second ejector 107 (point h in the figure). After mixing in the second ejector 107, it becomes a two-phase gas-liquid working fluid at the outlet of the second ejector 107 (point j in the figure). The remaining working fluid in the first liquid separator condenser 103 continues to condense into a liquid working fluid (point f in the figure). After being throttled by the second throttling valve 104 and the third throttling valve 105 in sequence (point g in the figure), it enters the gas separator evaporator 106. The two-phase working fluid at the outlet of the second injector 107 (point j in the figure) undergoes partial condensation in the second liquid separator condenser 108. The condensed liquid working fluid (point l in the figure) is separated from the liquid outlet of the second liquid separator condenser 108 and enters the flash tank 110 (point m in the figure) through the first throttle valve 109. The remaining working fluid in the second liquid separator condenser 108 continues to condense into a liquid working fluid (point k in the figure), mixes with the gas-liquid two-phase working fluid at the outlet of the second throttle valve 104, and then enters the inlet of the third throttle valve 105. Inside the flash evaporator 110, gas and liquid are separated. The saturated gaseous working medium at the gas phase outlet of the flash evaporator 110 (point n in the figure) enters the second gas supply port 1014 of the multi-stage gas supply compressor 101, and the saturated liquid working medium at the liquid phase outlet of the flash evaporator 110 enters the ejector inlet of the first ejector 111 (point o in the figure). The vaporized working medium separated from the gas distribution outlet of the gas separator evaporator 106 enters the ejector inlet of the first ejector 111 (point p in the figure). After mixing in the first ejector 111, it becomes a two-phase gas-liquid working medium at the outlet of the first ejector 111 (point q in the figure), and then passes through the high-pressure evaporator 112 for evaporation. The vaporized working medium at the outlet of the high-pressure evaporator 112 (point r in the figure) enters the first gas supply port 1013 of the multi-stage gas supply compressor 101. The remaining working medium in the gas separator evaporator 106 continues to evaporate into a vaporized working medium (point a in the figure) and enters the inlet 1011 of the multi-stage gas supply compressor. During the pressurization process, the gaseous working medium at the inlet 1011 of the multi-stage gas-supply compressor is sequentially mixed with the gaseous working medium at the first gas supply port 1013 and the second gas supply port 1014 of the multi-stage gas-supply compressor 101 (points b and c in the figure), and then exits from the outlet 1012 of the multi-stage gas-supply compressor. A portion of the gaseous working medium at the outlet 1012 of the multi-stage gas-supply compressor (point d in the figure) enters the high-pressure compressor 102, thus completing the entire cycle.

[0057] Example 4

[0058] The following is an embodiment of a heat exchange system of the present invention, including a multi-stage injection high-temperature heat pump system as described above, a heat sink side heat exchange module 113, and a heat source side heat exchange module 114. The heat sink side heat exchange module 113 is connected in sequence to the second liquid separator condenser 108 and the first liquid separator condenser 103, and the heat source side heat exchange module 114 is connected in sequence to the high-pressure evaporator 112 and the gas separator evaporator 106.

[0059] The heat exchange module 113 on the heat sink side is used to exchange heat with the second liquid separator condenser 108 and the first liquid separator condenser 103, and the heat exchange module 114 on the heat source side is used to exchange heat with the high-pressure evaporator 112 and the gas separator evaporator 106, so that the second liquid separator condenser 108, the first liquid separator condenser 103, the high-pressure evaporator 112 and the gas separator evaporator 106 can all realize the function of adjusting the working fluid composition and flow rate through their internal structure.

[0060] In this embodiment, the heat sink side fluid first passes through the heat sink side of the second liquid separator condenser 108, and then through the heat sink side of the first liquid separator condenser 103. The flow direction of the heat sink side fluid is opposite to that of the working fluid, which is a countercurrent heat exchange form. The heat source side fluid first passes through the heat source side of the high-pressure evaporator 112, and then through the heat source side of the gas separator evaporator 106. The flow direction of the heat source side fluid is opposite to that of the working fluid, which is a countercurrent heat exchange form.

[0061] Example 5

[0062] The following is an embodiment of a control method for a multi-stage injection high-temperature heat pump system according to the present invention, applied to the multi-stage injection high-temperature heat pump system as described above, and the operation is as follows:

[0063] The working pressures of the first liquid separator condenser 103, the second liquid separator condenser 108, the second ejector 107, the multi-stage gas compressor 101, the flash tank 110, the first ejector 111, the high-pressure evaporator 112, and the gas-distributing evaporator 106 are controlled and classified into pressure levels. The working pressure of the first liquid separator condenser 103 is defined as level six, the working pressures of the second liquid separator condenser 108 and the second ejector 107 are level five, the pressure at the outlet 1012 of the multi-stage gas compressor 101 is level four, the working pressure of the flash tank 110 is level three, the working pressures of the first ejector 111 and the high-pressure evaporator 112 are level two, and the working pressure of the gas-distributing evaporator 106 is level one. The working pressures of each part meet the following conditions: level six pressure > level five pressure > level four pressure > level three pressure > level two pressure > level one pressure.

[0064] Control the liquid flow rate of the first liquid condenser 103 and the second liquid condenser 108, the gas flow rate of the gas evaporator 106, and the branch flow rate from the multi-stage gas compressor 101 to the second ejector 107, and ensure that the liquid flow rate of the first liquid condenser 103 is less than the main flow rate of the first liquid condenser 103, the liquid flow rate of the second liquid condenser 108 is less than the main flow rate of the second liquid condenser 108, the gas flow rate of the gas evaporator 106 is less than the main flow rate of the gas evaporator 106, and the branch flow rate from the multi-stage gas compressor 101 to the second ejector 107 is less than the branch flow rate from the multi-stage gas compressor 101 to the first liquid condenser 103.

[0065] In this embodiment, the pressure of the liquid working fluid from the liquid outlet of the first liquid separator condenser 103 in the second ejector 107 is greater than the pressure of the gas working fluid at the outlet of the multi-stage gas compressor 1012. The liquid working fluid at the sixth-stage pressure enters the second ejector 107 as the working fluid, converts pressure into velocity, and then ejects a portion of the gas working fluid at the fourth-stage pressure at the outlet of the multi-stage gas compressor 1012, forming a gas-liquid two-phase working fluid at the fifth-stage pressure at the outlet of the second ejector 107. In practical applications, the liquid working fluid at the fifth-stage pressure at the liquid outlet of the second liquid separator condenser 108 is throttled and depressurized by the first throttling valve 109, forming a gas-liquid two-phase working fluid at the third-stage pressure at the inlet of the flash tank 110. The liquid working fluid pressure from the liquid outlet of the flash tank 110 in the first ejector 111 is greater than the gas working fluid pressure at the gas distribution outlet of the gas separator 106. The liquid working fluid at the third-stage pressure enters the first ejector 111 as the working fluid, converting pressure into velocity, and then ejects the gas working fluid at the first-stage pressure at the gas distribution outlet of the gas separator 106, forming a two-phase gas-liquid working fluid at the second-stage pressure at the outlet of the first ejector 111. Furthermore, the system operates at six different pressures during its cycle, from highest to lowest: sixth-stage pressure, fifth-stage pressure, fourth-stage pressure, third-stage pressure, second-stage pressure, and first-stage pressure. The sixth-stage pressure and the first-stage pressure are determined by the operating conditions of the cycle system (i.e., a condensing temperature and an evaporating temperature), which in turn depend on the heating temperature requirements and the ambient air temperature.

[0066] In this embodiment, a multi-stage compression intermediate cooling method is adopted. After the gaseous working fluid at the inlet 1011 of the multi-stage gas-supply compressor is pressurized, it is mixed with the gaseous working fluid at the first gas-supply port 1013 of the multi-stage gas-supply compressor 101. The mixed gaseous working fluid is pressurized again and mixed with the gaseous working fluid at the second gas-supply port 1014 of the multi-stage gas-supply compressor 101. The mixed gaseous working fluid is pressurized again and leaves the outlet 1012 of the multi-stage gas-supply compressor.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. 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 claims of the present invention.

Claims

1. A multi-stage injection-type high-temperature heat pump system, characterized in that, It includes a multi-stage gas-fuel compressor (101), a first liquid-liquid separator (103), a first throttle valve (109), a flash tank (110), a first ejector (111), a second throttle valve (104), and a gas-fuel evaporator (106). The outlet (1012) of the multi-stage gas compressor is connected to the inlet of the first liquid separator (103); one outlet of the first liquid separator (103) is connected to the inlet of the flash tank (110) through the first throttle valve (109), and the other outlet of the first liquid separator (103) is connected to the inlet of the gas separator (106) through the second throttle valve (104); one outlet of the flash tank (110), the outlet of the first ejector (111), and one outlet of the gas separator (106) are respectively connected to different inlets of the multi-stage gas compressor (101); the other outlet of the flash tank (110) is connected to one inlet of the first ejector (111); and the other outlet of the gas separator (106) is connected to the other inlet of the first ejector (111).

2. The multi-stage injection high-temperature heat pump system according to claim 1, characterized in that, The inlet of the multi-stage gas compressor (101) includes at least a multi-stage gas compressor inlet (1011), a first gas inlet (1013) and a second gas inlet (1014), the outlet of the first injector (111) is connected to the first gas inlet (1013), and one of the outlets of the flash tank (110) is connected to the second gas inlet (1014).

3. The multi-stage injection high-temperature heat pump system according to claim 2, characterized in that, It also includes a high-pressure evaporator (112), and the outlet of the first injector (111) is connected to the first air supply port (1013) through the high-pressure evaporator (112).

4. The multi-stage injection high-temperature heat pump system according to claim 3, characterized in that, It also includes a second liquid separator condenser (108), a second ejector (107), a third throttle valve (105), and a high-pressure compressor (102). The outlet of the multi-stage gas-supply compressor (101) is divided into two paths. One path is connected to the inlet of the first liquid separator condenser (103) through the high-pressure compressor (102), and the other path of the outlet of the multi-stage gas-supply compressor (101) is connected to the inlet of the second liquid separator condenser (108) through the second ejector (107). The second ejector (107) is located in the first liquid separator condenser (108). 3) It is connected to and between the second liquid separator (108) and both of them. One outlet of the second liquid separator (108) is connected to the inlet of the flash tank (110) through the first throttle valve (109). The other outlet of the second liquid separator (108) is connected to the inlet of the gas separator (106) through the third throttle valve (105). One outlet of the first liquid separator (103) is connected to the inlet of the gas separator (106) in sequence through the second throttle valve (104) and the third throttle valve (105).

5. The multi-stage injection high-temperature heat pump system according to any one of claims 1 to 4, characterized in that, The first liquid separator condenser (103) includes a condenser manifold (1032), multiple condenser heat exchange tubes (1031), a liquid separator pipe (1033), and a liquid separator plate (1034). The liquid separator plate (1034) is provided with multiple liquid separator holes (1035). The liquid separator plate (1034) is installed in the condenser manifold (1032). The multiple condenser heat exchange tubes (1031) are arranged in sequence and interconnected with each other and are all connected to the condenser manifold (1032). The liquid separator pipe (1033) is also connected to the condenser manifold (1032). The inlet of the condenser manifold (1032) is connected to the outlet (1012) of the multi-stage gas compressor. The outlet of the condenser manifold (1032) is connected to the inlet of the second throttle valve (104). The liquid separator pipe (1033) is connected to the inlet of the flash tank (110) through the first throttle valve (109).

6. The multi-stage injection high-temperature heat pump system according to any one of claims 1 to 4, characterized in that, The gas-distributing evaporator (106) includes an evaporation header (1062), multiple evaporation heat exchange tubes (1061), an evaporation gas distribution pipe (1063), and an evaporation baffle (1064). The evaporation baffle (1064) is located in the evaporation header (1062). The multiple evaporation heat exchange tubes (1061) are arranged sequentially and interconnected with each other and are all connected to the evaporation header (1062). The evaporation gas distribution pipe (1063) is also connected to the evaporation header (1062). The inlet of the evaporation header (1062) is connected to the outlet of the second throttle valve (104). The outlet of the evaporation header (1062) is connected to the inlet (1011) of the multi-stage gas compressor. The evaporation gas distribution pipe (1063) is connected to one of the inlets of the first injector (111).

7. The multi-stage injection high-temperature heat pump system according to claim 1, characterized in that, The inlet of the first injector (111) is divided into an ejector inlet and an ejected inlet. The ejector inlet is connected to the liquid phase outlet of the flash tank (110), and the ejected inlet is connected to the gas distribution outlet of the gas separator (106).

8. The multi-stage injection high-temperature heat pump system according to claim 7, characterized in that, The working pressure of the ejector inlet is greater than the working pressure of the ejected inlet.

9. A heat exchange system, characterized in that, The system includes the multi-stage gas injection high-temperature heat pump system as described in claim 4, a heat sink side heat exchange module (113), and a heat source side heat exchange module (114). The heat sink side heat exchange module (113) is connected in series with the second liquid separator (108) and the first liquid separator (103). The heat source side heat exchange module (114) is connected in series with the high-pressure evaporator (112) and the gas separator (106).

10. A control method for a multi-stage injection-type high-temperature heat pump system, characterized in that, When applied to the multi-stage injection-type high-temperature heat pump system as described in claim 4, the operation is as follows: The working pressures of the first liquid separator (103), the second liquid separator (108), the second ejector (107), the multi-stage gas compressor (101), the flash tank (110), the first ejector (111), the high-pressure evaporator (112), and the gas separator (106) are controlled and classified into pressure levels. The working pressure of the first liquid separator (103) is defined as level 6, the working pressures of the second liquid separator (108) and the second ejector (107) are level 5, the pressure at the outlet (1012) of the multi-stage gas compressor (101) is level 4, the working pressure of the flash tank (110) is level 3, the working pressures of the first ejector (111) and the high-pressure evaporator (112) are level 2, and the working pressure of the gas separator (106) is level 1. The working pressures of each part meet the following conditions: level 6 pressure > level 5 pressure > level 4 pressure > level 3 pressure > level 2 pressure > level 1 pressure. Control the liquid flow rate of the first liquid condenser (103) and the second liquid condenser (108), the gas flow rate of the gas evaporator (106), and the branch flow rate from the multi-stage gas compressor (101) to the second injector (107), and make the liquid flow rate of the first liquid condenser (103) < the main flow rate of the first liquid condenser (103), the liquid flow rate of the second liquid condenser (108) < the main flow rate of the second liquid condenser (108), the gas flow rate of the gas evaporator (106) < the main flow rate of the gas evaporator (106), and the branch flow rate from the multi-stage gas compressor (101) to the second injector (107) < the branch flow rate from the multi-stage gas compressor (101) to the first liquid condenser (103).

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