A cascade heat pump system

Abstract

This invention provides a cascade heat pump system, relating to the field of heat pump systems. In a first loop, a first compressor, a first heat exchanger, a second heat exchanger, and an evaporator are sequentially arranged. The first loop heats the second loop via the first heat exchanger. Further, a second heat exchanger is added between the first and evaporators, and an auxiliary branch is provided between the second heat exchanger and the evaporator. This auxiliary branch passes through the second heat exchanger and connects to the first compressor. Thus, when the evaporator's processing efficiency cannot match the working fluid flow rate, causing a decrease in the heating capacity of the first loop, the remaining working fluid at the evaporator inlet can pass through the auxiliary branch, exchange heat with the second heat exchanger, and then enter the first compressor, and finally enter the first heat exchanger to achieve the heating effect. This ensures the efficiency of the entire heat pump system, enabling the cascade heat pump system to operate stably and reliably.

Description

Technical Field

[0001] This application relates to the field of heat pump systems, and more particularly to a cascade heat pump system. Background Technology

[0002] Cascade heat pump systems are suitable for low-temperature environments. Existing cascade heat pump systems typically consist of two single loops (a low-temperature loop and a high-temperature loop). These two loops complete the heat transfer between the two stages of the heat pump through a heat exchanger. That is, at the heat exchanger, the low-temperature loop can provide heat to supply the high-temperature loop. In existing systems, the working fluid in the low-temperature loop releases heat at the heat exchanger and then directly enters the evaporator to absorb heat and evaporate before entering the compressor. During the process of the working fluid entering the evaporator from the heat exchanger, if the evaporator's processing efficiency cannot match the working fluid flow rate, it will cause a decrease in the heat supply of the low-temperature loop (which is the high-temperature loop), affecting the efficiency of the entire heat pump system. In other words, existing cascade heat pump systems cannot guarantee the reliability and stability of operation. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a cascade heat pump system to solve the problem that existing cascade heat pump systems cannot guarantee operational stability.

[0004] In accordance with the above objectives, this utility model provides a cascade heat pump system, including a first loop and a second loop, wherein the first loop and the second loop are connected through a first heat exchanger;

[0005] The first circuit includes a first compressor, a first heat exchanger, a second heat exchanger, and an evaporator arranged in sequence; an auxiliary branch is formed between the second heat exchanger and the evaporator, and the auxiliary branch passes through the second heat exchanger and communicates with the first compressor.

[0006] Preferably, the first circuit includes a first main circuit, on which the first compressor, the first oil separator, the first heat exchanger, the second heat exchanger, the evaporator, and the first gas-liquid separator are sequentially arranged.

[0007] Preferably, the first main circuit is connected to the first inlet and the first outlet of the first heat exchanger; the first main circuit is also connected to the first inlet and the first outlet of the second heat exchanger.

[0008] Preferably, the auxiliary branch forms a first auxiliary branch, the first end of the first auxiliary branch is connected to the first main circuit, and the first end of the first auxiliary branch is located between the second heat exchanger and the evaporator; the second end of the first auxiliary branch is connected to the second inlet of the second heat exchanger.

[0009] Preferably, the auxiliary branch forms a second auxiliary branch, the first end of the second auxiliary branch is connected to the second outlet of the second heat exchanger, and the second end of the second auxiliary branch is connected to the first compressor.

[0010] Preferably, a first throttling device and a second throttling device are also provided on the first main circuit, and the first throttling device and the second throttling device are located between the second heat exchanger and the evaporator;

[0011] The first end of the first auxiliary branch is located between the first throttle and the second throttle.

[0012] Preferably, the second circuit includes a second main circuit, on which a second compressor, a second oil separator, a condenser, a first heat exchanger, and a second gas-liquid separator are sequentially arranged;

[0013] The second main circuit is connected to the second inlet and the second outlet of the first heat exchanger.

[0014] Preferably, a third throttle is also provided on the second main circuit, and the third throttle is located between the condenser and the first heat exchanger.

[0015] Preferably, both the first compressor and the second compressor are equipped with high-temperature resistant motors.

[0016] Preferably, both the first compressor and the second compressor are equipped with high-temperature refrigeration oil.

[0017] According to the cascade heat pump system of this utility model, a first compressor, a first heat exchanger, a second heat exchanger, and an evaporator are sequentially arranged in the first loop (i.e., the low-temperature loop mentioned above). The first loop heats the second loop (i.e., the high-temperature loop mentioned above) through the first heat exchanger. Furthermore, a second heat exchanger is added between the first heat exchanger and the evaporator, and an auxiliary branch is provided between the second heat exchanger and the evaporator. This auxiliary branch can pass through the second heat exchanger and connect to the first compressor. Therefore, when the evaporator's processing efficiency cannot match the working fluid flow rate, causing a decrease in the heating supply of the first loop, the remaining working fluid at the evaporator inlet can enter the first compressor through the second heat exchanger via the auxiliary branch, and then enter the first heat exchanger to achieve the heating effect. In this way, the efficiency of the entire heat pump system can be guaranteed, enabling the cascade heat pump system to operate stably and reliably.

[0018] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a cascade heat pump system according to an embodiment of the present invention.

[0021] Icons: 11-First main circuit; 12-First compressor; 13-First oil separator; 14-First heat exchanger; 15-Second heat exchanger; 161-First throttle; 162-Second throttle; 17-Evaporator; 18-First gas-liquid separator; 191-First auxiliary branch; 192-Second auxiliary branch; 21-Second main circuit; 22-Second compressor; 23-Second oil separator; 24-Condenser; 25-Third throttle; 26-Second gas-liquid separator. Detailed Implementation

[0022] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0023] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0024] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0025] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0026] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0027] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0028] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0029] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0030] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0031] This utility model provides a cascade heat pump system, such as Figure 1 As shown, the cascade heat pump system in this embodiment includes a first loop and a second loop, which are connected by a first heat exchanger 14. The first heat exchanger 14 enables heat transfer between the two loops; that is, at the first heat exchanger 14, the first loop provides heat to supply the second loop. The specific structure and connection relationships of the above-mentioned parts of the cascade heat pump system according to this invention will be described in detail below.

[0032] In this embodiment, as Figure 1 As shown, the first circuit includes a first main circuit 11, on which a first compressor 12, a first oil separator 13, a first heat exchanger 14, a second heat exchanger 15, an evaporator 17, and a first gas-liquid separator 18 are sequentially arranged; furthermore, the first main circuit 11 is connected to the first inlet and the first outlet of the first heat exchanger 14; the first main circuit 11 is also connected to the first inlet and the first outlet of the second heat exchanger 15.

[0033] Furthermore, the first circuit also includes an auxiliary branch, specifically a first auxiliary branch 191. The first end of the first auxiliary branch 191 is connected to the aforementioned first main circuit 11, and the first end of the first auxiliary branch 191 is located between the second heat exchanger 15 and the evaporator 17. The second end of the first auxiliary branch 191 is connected to the second inlet of the second heat exchanger 15. Further, the auxiliary branch also forms a second auxiliary branch 192. The first end of the second auxiliary branch 192 is connected to the second outlet of the second heat exchanger 15, and the second end of the second auxiliary branch 192 is connected to the first compressor 12. Even further, the first main circuit 11 is also equipped with a first throttling device 161 and a second throttling device 162, located between the second heat exchanger 15 and the evaporator 17. The first end of the first auxiliary branch 191 is located between the first throttling device 161 and the second throttling device 162.

[0034] In the first loop, a low-temperature, low-pressure gaseous working fluid enters the first compressor 12 and is compressed into a high-temperature, high-pressure gaseous working fluid. The high-temperature, high-pressure gaseous working fluid then enters the first heat exchanger 14 to release heat and form a high-pressure, medium-temperature liquid working fluid. The high-pressure, medium-temperature liquid working fluid (in the first main loop 11) is throttled by the first throttle 161 and the second throttle 162 into a low-temperature, low-pressure two-phase working fluid. Part of the two-phase working fluid passes through the evaporator 17 to form a low-temperature, low-pressure gaseous working fluid, and the other part passes through the second heat exchanger 15 to exchange heat with the high-pressure, medium-temperature liquid working fluid to form a low-temperature, low-pressure gaseous working fluid. Finally, the low-temperature, low-pressure gaseous working fluid enters the first compressor 12 and is compressed again to complete the working fluid cycle of the first loop.

[0035] In this embodiment, as Figure 1 As shown, the second circuit includes a second main circuit 21, on which a second compressor 22, a second oil separator 23, a condenser 24, the aforementioned first heat exchanger 14, and a second gas-liquid separator 26 are sequentially arranged. Furthermore, the second main circuit 21 is connected to the second inlet and the second outlet of the first heat exchanger 14. In addition, a third throttle valve 25 is also provided on the second main circuit 21, located between the condenser 24 and the first heat exchanger 14.

[0036] In the second loop, the medium-temperature, low-pressure gaseous working fluid is compressed into a high-temperature, high-pressure gaseous working fluid by the second compressor 22. The high-temperature, high-pressure gaseous working fluid then enters the condenser 24 to release heat and form a high-pressure, medium-temperature liquid working fluid. This heat pump system is connected to the user end through the condenser 24, meaning that the high-temperature, high-pressure gaseous working fluid releases heat at the condenser 24, enabling the heat pump system to output hot air or hot water. Then, the high-pressure, medium-temperature liquid working fluid is throttled into a medium-temperature, low-pressure two-phase working fluid by the third throttling device 25. This working fluid then enters the first heat exchanger 14 to exchange heat with the high-temperature, high-pressure gaseous working fluid in the first loop. That is, the medium-temperature, low-pressure two-phase working fluid in the second loop absorbs heat to form a medium-temperature, low-pressure gaseous working fluid, and returns to the second compressor 22 to be compressed again, thus completing the working fluid cycle of the second loop.

[0037] Furthermore, in this heat pump system, the first oil separator 13 and the second oil separator 23 can separate the lubricating oil from the high-pressure steam discharged by the first compressor 12 and the second compressor 22, respectively, to ensure the safe and efficient operation of the system. Similarly, the first gas-liquid separator 18 and the second gas-liquid separator 26 can ensure that the first compressor 12 and the second compressor 22 only draw in gaseous working fluid, thereby ensuring the reliability of the compressors.

[0038] Preferably, both the first compressor 12 and the second compressor 22 are equipped with high-temperature resistant motors; both the first compressor 12 and the second compressor 22 are equipped with high-temperature resistant refrigeration oil, which can further improve the performance and reliability of the entire heat pump system.

[0039] According to the cascade heat pump system of this utility model, a first compressor 12, a first heat exchanger 14, a second heat exchanger 15, and an evaporator 17 are sequentially arranged in the first loop. The first loop heats the second loop through the first heat exchanger 14. Further, a second heat exchanger 15 is added between the first heat exchanger 14 and the evaporator 17, and an auxiliary branch is provided between the second heat exchanger 15 and the evaporator 17. This auxiliary branch can pass through the second heat exchanger 15 and connect to the first compressor 12. Therefore, when the processing efficiency of the evaporator 17 cannot match the working fluid flow rate, resulting in a decrease in the heating supply of the first loop, the remaining working fluid at the inlet of the evaporator 17 can enter the first compressor 12 through the second heat exchanger 15 via the auxiliary branch, and then enter the first heat exchanger 14 to achieve the heating effect. In this way, the efficiency of the entire heat pump system can be guaranteed, enabling the cascade heat pump system to operate stably and reliably.

[0040] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A cascade heat pump system comprising a first circuit and a second circuit, characterized in that, The first circuit and the second circuit are connected via a first heat exchanger; The first circuit includes a first compressor, a first heat exchanger, a second heat exchanger, and an evaporator arranged in sequence; an auxiliary branch is formed between the second heat exchanger and the evaporator, and the auxiliary branch passes through the second heat exchanger and communicates with the first compressor.

2. The cascade heat pump system of claim 1, wherein, The first circuit includes a first main circuit, on which the first compressor, the first oil separator, the first heat exchanger, the second heat exchanger, the evaporator, and the first gas-liquid separator are sequentially arranged.

3. The cascade heat pump system of claim 2, wherein, The first main circuit is connected to the first inlet and the first outlet of the first heat exchanger; the first main circuit is connected to the first inlet and the first outlet of the second heat exchanger.

4. The cascade heat pump system of claim 3, wherein, The auxiliary branch forms a first auxiliary branch, the first end of the first auxiliary branch is connected to the first main circuit, and the first end of the first auxiliary branch is located between the second heat exchanger and the evaporator; the second end of the first auxiliary branch is connected to the second inlet of the second heat exchanger.

5. The cascade heat pump system of claim 4, wherein, The auxiliary branch forms a second auxiliary branch, the first end of the second auxiliary branch is connected to the second outlet of the second heat exchanger, and the second end of the second auxiliary branch is connected to the first compressor.

6. The cascade heat pump system of claim 4, wherein, The first main circuit is also equipped with a first throttle and a second throttle, which are located between the second heat exchanger and the evaporator. The first end of the first auxiliary branch is located between the first throttle and the second throttle.

7. The cascade heat pump system of claim 1, wherein, The second circuit includes a second main circuit, on which a second compressor, a second oil separator, a condenser, a first heat exchanger, and a second gas-liquid separator are sequentially arranged. The second main circuit is connected to the second inlet and the second outlet of the first heat exchanger.

8. The cascade heat pump system of claim 7, wherein, A third throttle is also provided on the second main circuit, and the third throttle is located between the condenser and the first heat exchanger.

9. The cascade heat pump system of claim 7, wherein, Both the first compressor and the second compressor are equipped with high-temperature resistant motors.

10. The cascade heat pump system of claim 7, wherein, Both the first compressor and the second compressor are equipped with high-temperature refrigeration oil.

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