A waste heat recovery cascade refrigeration system
By designing a waste heat recovery cascade refrigeration system, and utilizing the alternating operation of refrigerants with different boiling points and pipeline connections, the problems of complex structure, high energy consumption, and low refrigeration efficiency of cascade refrigeration systems are solved, achieving a highly efficient and stable refrigeration effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU SUSHI TESTING INSTR CO LTD
- Filing Date
- 2025-06-10
- Publication Date
- 2026-06-30
AI Technical Summary
Existing cascade refrigeration systems are complex in structure, have high energy consumption and low refrigeration efficiency. In particular, the flash gas caused by insufficient subcooling of the refrigerant affects the evaporation heat exchange effect.
The waste heat recovery cascade refrigeration system adopts the alternating operation of the first and second refrigeration modules and the connection of pipelines to use refrigerants with different boiling points for heat exchange, so as to achieve sufficient subcooling of the refrigerant. The pressure is balanced by the bypass branch, which reduces the structural complexity and energy consumption.
It improves refrigeration efficiency, reduces system energy consumption, simplifies the structure, reduces maintenance difficulty, and ensures evaporative heat exchange effect and stable system operation.
Smart Images
Figure CN224434725U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of refrigeration technology, specifically to a waste heat recovery cascade refrigeration system. Background Technology
[0002] In the field of environmental test chambers, cascade refrigeration systems have become a commonly used refrigeration method due to their ability to achieve lower temperatures. This system uses two compressors to charge refrigerants with different boiling points to achieve cooling, meeting the temperature control requirements of the test chamber over a wide range.
[0003] Currently, to ensure temperature control accuracy, some cascade refrigeration systems employ bypass branches for auxiliary temperature control, such as by setting up a refrigerant mixing branch to adjust the load temperature and compressor return gas temperature. However, this system also has the following problems:
[0004] 1. The system contains multiple compressors, condensers and other components, which are complex in structure. The bypass branch further increases the structural complexity and the difficulty of maintenance.
[0005] 2. The presence of multiple compressors, condensers, and other components leads to high system energy consumption, resulting in higher operating costs.
[0006] 3. The refrigerant may not be sufficiently subcooled after passing through the condenser or heat exchanger. This can cause flash gas to be generated when the refrigerant is depressurized and cooled at the throttling element, which affects the evaporation heat exchange effect and ultimately reduces the refrigeration efficiency.
[0007] Therefore, how to overcome the shortcomings of the existing technology mentioned above has become the subject of this utility model. Utility Model Content
[0008] The purpose of this invention is to provide a waste heat recovery cascade refrigeration system.
[0009] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0010] A waste heat recovery cascade refrigeration system includes a first refrigeration module and a second refrigeration module;
[0011] The first refrigeration module includes:
[0012] First compressor;
[0013] The first heat exchanger has its first feed end connected to the discharge end of the first compressor via a first pipe.
[0014] The second heat exchanger has its first feed end connected to the first discharge end of the first heat exchanger via a second pipe.
[0015] The evaporator is connected to the first discharge end of the second heat exchanger via a third pipe and to the feed end of the first compressor via a fourth pipe.
[0016] The fifth pipe is connected at both ends to the third pipe and the second feed end of the second heat exchanger, respectively.
[0017] The sixth pipe is connected at both ends to the second discharge end of the second heat exchanger and the feed end of the first compressor, respectively.
[0018] The first pressure-reducing component is provided at least in the third pipeline;
[0019] The second refrigeration module includes:
[0020] Second compressor;
[0021] A condenser, wherein the feed end of the condenser is connected to the discharge end of the second compressor via a first flow channel;
[0022] The third heat exchanger has its first feed end connected to the discharge end of the condenser via a second flow channel;
[0023] The third flow channel is connected at both ends to the first discharge end of the third heat exchanger and the second inlet end of the first heat exchanger, respectively.
[0024] The fourth flow channel is connected at both ends to the second discharge end of the first heat exchanger and the feed end of the second compressor, respectively.
[0025] The fifth flow channel is connected at both ends to the third flow channel and the second feed end of the third heat exchanger, respectively.
[0026] The sixth flow channel is connected at both ends to the second discharge end of the third heat exchanger and the inlet end of the second compressor, respectively.
[0027] The second pressure-reducing component is provided at least in the third flow channel.
[0028] The first refrigeration module can cool the internal structure of the environmental test chamber, and the second refrigeration module exchanges heat with the first refrigeration module.
[0029] The heat exchanger itself is an existing setup, and the specific settings of its discharge and feed ends will not be described in detail here. There are also no restrictions on the type of heat exchanger.
[0030] The first compressor is the same type as the second compressor, but it is charged with refrigerants with different boiling points to meet the larger cooling load.
[0031] The working process of the refrigeration system is as follows:
[0032] First, the second refrigeration module is started, and the high-temperature and high-pressure refrigeration vapor discharged from the second compressor enters the condenser for cooling and then enters the third heat exchanger.
[0033] The third heat exchanger discharges medium-temperature, high-pressure refrigerant. Then, this portion of refrigerant is processed by the second pressure-reducing component and converted into low-temperature, low-pressure liquid refrigerant. Part of the liquid refrigerant flows back into the third heat exchanger through the fifth flow channel and is converted into gaseous refrigerant by exchanging heat with the medium-temperature, high-pressure refrigerant output from the condenser. Then it flows back to the feed end of the second compressor.
[0034] Another portion of the low-temperature, low-pressure liquid refrigerant enters the second feed end of the first heat exchanger along the main path (third flow channel). This portion of liquid refrigerant is also converted into gaseous refrigerant after heat exchange, and then flows back to the feed end of the second compressor, thus creating a cycle.
[0035] After the second refrigeration module is started, the first refrigeration module is started. The high-temperature and high-pressure refrigeration vapor discharged from the first compressor enters the first heat exchanger and exchanges heat with the low-temperature and low-pressure liquid refrigerant discharged from the second refrigeration module into the first heat exchanger, and then enters the second heat exchanger.
[0036] The second heat exchanger discharges medium-temperature, high-pressure refrigerant. Then, this portion of refrigerant is processed by the first pressure-reducing component and converted into low-temperature, low-pressure liquid refrigerant. Part of the liquid refrigerant flows back into the second heat exchanger through the fifth pipe and is converted into gaseous refrigerant by exchanging heat with the medium-temperature, high-pressure refrigerant output from the first heat exchanger. Then, it flows back to the feed end of the first compressor.
[0037] Another portion of the low-temperature, low-pressure liquid refrigerant enters the evaporator along the main path (third pipe). This portion of liquid refrigerant is also converted into gaseous refrigerant and then flows back to the feed end of the first compressor, thus creating a cycle.
[0038] It should be noted that the descriptions of high temperature and high pressure are only to indicate the differences in refrigerants at different stages. Taking temperature as an example, the above mentions high temperature, medium temperature and low temperature. The specific temperature range is not the innovation of this application. For further understanding, please refer to the prior art. For example, the specific temperature range of high temperature and high pressure refrigeration vapor can be referred to the existing cascade refrigeration system.
[0039] The explanation will be based on the first compressor as an example; the explanation for the second compressor will follow the same pattern.
[0040] First, due to the setting of the fifth pipe, a portion of the refrigerant output from the first heat exchanger exchanges heat with another portion of the refrigerant output from the first heat exchanger through the second heat exchanger, which promotes the refrigerant that finally flows to the evaporator to achieve sufficient subcooling, and avoids the generation of flash gas in this portion of refrigerant during subsequent pressure and temperature reduction, thereby ensuring the evaporation heat exchange effect and refrigeration efficiency.
[0041] Second, by using a portion of the refrigerant output from the first heat exchanger to exchange heat with another portion of the refrigerant output from the first heat exchanger, the energy consumption of the refrigeration system can be reduced and the operating cost of the refrigeration system can be reduced by increasing the utilization rate of the refrigerant in the refrigeration system.
[0042] Third, the fifth and sixth pipes can form a bypass branch to balance the pressure at the intake end of the first compressor, avoiding the need to set up a separate bypass branch and reducing structural costs.
[0043] A further technical solution is that the first pressure-reducing component includes:
[0044] A first thermal expansion valve is located in the third pipeline;
[0045] A second thermal expansion valve is located in the fifth pipeline;
[0046] The second step-down component includes:
[0047] A third thermal expansion valve is located in the third flow channel;
[0048] The fourth thermal expansion valve is located in the fifth flow channel.
[0049] Let's take the first voltage-reducing component as an example:
[0050] On the one hand, thermal expansion valves are installed on both the third and fifth pipes, which can independently control the flow rate of the third and fifth pipes;
[0051] On the other hand, the connection points between the third and fifth pipes are not subject to many restrictions, allowing for flexible wiring layouts within the refrigeration system.
[0052] Without the second thermal expansion valve, the connection point between the third and fifth pipes would be significantly restricted, requiring the fluid to pass through the first thermal expansion valve before entering this connection point.
[0053] In a further technical solution, the first refrigeration module also includes:
[0054] A first control valve is located in the third pipeline;
[0055] The second control valve is located in the fifth pipeline;
[0056] The second refrigeration module also includes:
[0057] A third control valve is located in the third flow channel;
[0058] The fourth control valve is located in the fifth flow channel.
[0059] Taking the first control valve as an example, the second, third, and fourth control valves are explained in the same way: The first control valve is used in conjunction with the first pressure-reducing component. When the refrigeration system stops running, the first control valve can quickly cut off the flow of refrigerant before the first pressure-reducing component takes effect, so as to protect equipment such as the evaporator and achieve long-term stable operation of the refrigeration system.
[0060] In a further technical solution, the first refrigeration module also includes:
[0061] The seventh pipe is connected at both ends to the first pipe and the feed end of the first compressor, respectively.
[0062] The fifth control valve includes at least one control sub-valve located on the seventh pipeline;
[0063] The second refrigeration module also includes:
[0064] The seventh flow channel is connected at both ends to the first flow channel and the feed end of the second compressor, respectively.
[0065] The sixth control valve includes at least one control sub-valve disposed on the seventh flow channel.
[0066] The explanation uses the seventh pipe and the fifth control valve as an example; the seventh flow channel and the sixth control valve are explained in the same way.
[0067] First, the seventh pipe can be directly connected to the feed end of the first compressor, or it can be indirectly connected to the feed end of the first compressor (such as through the fourth pipe). This embodiment does not impose any restrictions.
[0068] Second, the fifth control valve may include two control sub-valves, one of which is a solenoid valve and the other is a bypass valve. The solenoid valve can quickly cut off or connect the seventh pipeline, avoiding pressure fluctuations or other problems caused by the slow response speed of the bypass valve.
[0069] Third, the seventh pipe forms a bypass branch, which is initially in a closed state. When the pressure at the feed end of the first compressor is too low, this bypass branch opens. This bypass branch can directly guide a portion of the high-temperature and high-pressure refrigeration vapor discharged from the discharge end of the first compressor back to the feed end of the first compressor to balance the feed end pressure of the first compressor.
[0070] In a further technical solution, the sixth pipe is connected to the feed end of the first compressor via the fourth pipe;
[0071] The seventh pipe is connected to the feed end of the first compressor via the fourth pipe or the sixth pipe;
[0072] The sixth flow channel is connected to the feed end of the second compressor through the fourth flow channel;
[0073] The seventh flow channel is connected to the feed end of the second compressor via the fourth flow channel or the sixth flow channel.
[0074] Taking the example of the sixth pipe being connected to the feed end of the first compressor via the fourth pipe, similar descriptions in this embodiment refer to this explanation: The sixth pipe is not directly connected to the feed end of the first compressor. On the one hand, the length of the sixth pipe can be shortened to reduce structural costs; on the other hand, it can avoid the messy layout of multiple pipes at the feed end of the first compressor, which would affect the difficulty of subsequent maintenance.
[0075] In a further technical solution, the fifth control valve and the sixth control valve each include two control sub-valves connected in series.
[0076] For a description of the control sub-valve, please refer to the above implementation method. This implementation method further clarifies the specific settings of the fifth control valve and the sixth control valve.
[0077] In a further technical solution, the first refrigeration module also includes:
[0078] The eighth pipe is connected at both ends to the fifth pipe and the sixth pipe, respectively;
[0079] The seventh control valve is located in the eighth pipeline;
[0080] The second refrigeration module also includes:
[0081] The eighth flow channel is connected at both ends to the fifth flow channel and the sixth flow channel, respectively.
[0082] The eighth control valve is located in the eighth flow channel.
[0083] Taking the eighth pipe as an example, the eighth flow channel is explained in the same way: the eighth pipe is actually a bypass branch. The eighth pipe is initially in a closed state. When the pressure at the feed end of the first compressor is too high, the eighth pipe opens, and part of the liquid refrigerant that has entered the fifth pipe flows directly through the eighth pipe to the feed end of the first compressor to balance the pressure at the feed end of the first compressor.
[0084] The feed end of the first compressor may also experience excessively high temperatures. In this case, low-temperature, low-pressure liquid refrigerant can be supplied to the feed end of the first compressor through the sixth pipe to cool it down and protect the first compressor from damage. This replaces the method of continuously starting and stopping the first compressor to achieve the cooling effect, thus saving energy.
[0085] Before the eighth pipe was installed, the sixth pipe only transported the gaseous refrigerant output from the second heat exchanger; after the eighth pipe was installed, the liquid refrigerant and the gaseous refrigerant merged in the sixth pipe and were transported to the feed end of the first compressor.
[0086] In a further technical solution, the first refrigeration module also includes:
[0087] Storage containers;
[0088] The ninth pipe is connected at both ends to the first pipe and the inlet of the storage container, respectively.
[0089] The ninth control valve is located in the ninth pipeline;
[0090] The tenth pipe is connected at both ends to the discharge end of the storage container and the inlet end of the first compressor, respectively.
[0091] The tenth control valve is located in the tenth pipeline.
[0092] It should be noted that the first refrigeration module cools the internal parts of the equipment, while the second refrigeration module exchanges heat with the first refrigeration module. Because the refrigerant pressure inside the first compressor poses a high risk, the first compressor is used in conjunction with a storage container.
[0093] When the pressure in the main circuit of the first refrigeration module is higher than the set pressure, the refrigerant can flow into the storage container to protect the safety of the refrigeration system; when the pressure is lower than the set pressure, the refrigerant can flow from the storage container to the first compressor.
[0094] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.
[0095] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.
[0096] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.
[0097] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing this case.
[0098] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.
[0099] The working principle and advantages of this utility model are as follows:
[0100] Working principle: When the refrigeration system is running, the second refrigeration module is started first. The high-temperature and high-pressure refrigeration vapor discharged from the second compressor enters the condenser for cooling and then enters the third heat exchanger.
[0101] The third heat exchanger discharges medium-temperature, high-pressure refrigerant. Then, this portion of refrigerant is processed by the second pressure-reducing component and converted into low-temperature, low-pressure liquid refrigerant. Part of the liquid refrigerant flows back into the third heat exchanger through the fifth flow channel and is converted into gaseous refrigerant by exchanging heat with the medium-temperature, high-pressure refrigerant output from the condenser. Then it flows back to the feed end of the second compressor.
[0102] Another portion of the low-temperature, low-pressure liquid refrigerant enters the second feed end of the first heat exchanger along the main path (third flow channel). This portion of liquid refrigerant is also converted into gaseous refrigerant after heat exchange, and then flows back to the feed end of the second compressor, thus creating a cycle.
[0103] After the second refrigeration module is started, the first refrigeration module is started. The high-temperature and high-pressure refrigeration vapor discharged from the first compressor enters the first heat exchanger and exchanges heat with the low-temperature and low-pressure liquid refrigerant discharged from the second refrigeration module into the first heat exchanger, and then enters the second heat exchanger.
[0104] The second heat exchanger discharges medium-temperature, high-pressure refrigerant. Then, this portion of refrigerant is processed by the first pressure-reducing component and converted into low-temperature, low-pressure liquid refrigerant. Part of the liquid refrigerant flows back into the second heat exchanger through the fifth pipe and is converted into gaseous refrigerant by exchanging heat with the medium-temperature, high-pressure refrigerant output from the first heat exchanger. Then, it flows back to the feed end of the first compressor.
[0105] Another portion of the low-temperature, low-pressure liquid refrigerant enters the evaporator along the main path (third pipe). This portion of liquid refrigerant is also converted into gaseous refrigerant and then flows back to the feed end of the first compressor, thus creating a cycle.
[0106] The first refrigeration module will be used as an example for explanation; the second refrigeration module will follow the same explanation:
[0107] First, due to the setting of the fifth pipe, a portion of the refrigerant output from the first heat exchanger exchanges heat with another portion of the refrigerant output from the first heat exchanger through the second heat exchanger, which promotes the refrigerant that finally flows to the evaporator to achieve sufficient subcooling, and avoids the generation of flash gas in this portion of refrigerant during subsequent pressure and temperature reduction, thereby ensuring the evaporation heat exchange effect and refrigeration efficiency.
[0108] Second, by using a portion of the refrigerant output from the first heat exchanger to exchange heat with another portion of the refrigerant output from the first heat exchanger, the energy consumption of the refrigeration system can be reduced and the operating cost of the refrigeration system can be reduced by increasing the utilization rate of the refrigerant in the refrigeration system.
[0109] Third, the fifth and sixth pipes can form a bypass branch, thereby balancing the pressure at the intake end of the first compressor, avoiding the need to set up a separate bypass branch, reducing structural costs and maintenance difficulty. Attached Figure Description
[0110] Figure 1 This is a schematic diagram of a waste heat recovery cascade refrigeration system according to an embodiment of the present invention.
[0111] In the attached diagrams: 1. First refrigeration module; 11. First compressor; 12. First heat exchanger; 13. First pipe; 14. Second heat exchanger; 15. Second pipe; 16. Evaporator; 17. Third pipe; 18. Fourth pipe; 19. Fifth pipe; 101. Sixth pipe; 102. First pressure reducing component; 1021. First thermal expansion valve; 1022. Second thermal expansion valve; 103. First control valve; 104. Second control valve; 105. Seventh pipe; 106. Fifth control valve; 107. Eighth pipe; 108. Seventh control valve; 109. Storage container; 1001. Ninth pipe. 1. Flow channel; 1002. Ninth control valve; 1003. Tenth pipe; 1004. Tenth control valve; 2. Second refrigeration module; 21. Second compressor; 22. Condenser; 23. First flow channel; 24. Third heat exchanger; 25. Second flow channel; 26. Third flow channel; 27. Fourth flow channel; 28. Fifth flow channel; 29. Sixth flow channel; 201. Second pressure reducing component; 2011. Third thermostatic expansion valve; 2012. Fourth thermostatic expansion valve; 202. Third control valve; 203. Fourth control valve; 204. Seventh flow channel; 205. Sixth control valve; 206. Eighth flow channel; 207. Eighth control valve. Detailed Implementation
[0112] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0113] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.
[0114] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.
[0115] See Figure 1 A waste heat recovery cascade refrigeration system includes a first refrigeration module 1 and a second refrigeration module 2.
[0116] The first refrigeration module 1 includes:
[0117] First compressor 11;
[0118] The first heat exchanger 12, the first feed end of the first heat exchanger 12 is connected to the discharge end of the first compressor 11 through the first pipe 13;
[0119] The second heat exchanger 14 has its first feed end connected to the first discharge end of the first heat exchanger 12 via a second pipe 15.
[0120] Evaporator 16 is connected to the first discharge end of the second heat exchanger 14 via a third pipe 17, and to the feed end of the first compressor 11 via a fourth pipe 18;
[0121] The fifth pipe 19 is connected at both ends to the third pipe 17 and the second feed end of the second heat exchanger 14, respectively;
[0122] The sixth pipe 101 is connected at both ends to the second discharge end of the second heat exchanger 14 and the feed end of the first compressor 11, respectively.
[0123] The first pressure-reducing component 102 is provided at least in the third pipeline 17;
[0124] The second refrigeration module 2 includes:
[0125] Second compressor 21;
[0126] Condenser 22, the feed end of which is connected to the discharge end of the second compressor 21 through a first flow channel 23;
[0127] The third heat exchanger 24, the first feed end of the third heat exchanger 24 is connected to the discharge end of the condenser 22 through the second flow channel 25;
[0128] The third flow channel 26 is connected at both ends to the first discharge end of the third heat exchanger 24 and the second inlet end of the first heat exchanger 12, respectively.
[0129] The fourth flow channel 27 is connected at both ends to the second discharge end of the first heat exchanger 12 and the feed end of the second compressor 21, respectively.
[0130] The fifth flow channel 28 is connected at both ends to the third flow channel 26 and the second feed end of the third heat exchanger 24, respectively;
[0131] The sixth flow channel 29 is connected at both ends to the second discharge end of the third heat exchanger 24 and the feed end of the second compressor 21, respectively.
[0132] The second pressure-reducing component 201 is provided at least in the third flow channel 26.
[0133] The first refrigeration module 1 can cool the internal structure of the environmental test chamber, and the second refrigeration module 2 exchanges heat with the first refrigeration module 1.
[0134] The heat exchanger itself is an existing setup, and the specific settings of its discharge and feed ends will not be described in detail here. There are also no restrictions on the type of heat exchanger.
[0135] The first compressor 11 and the second compressor 21 are of the same type, but are charged with refrigerants with different boiling points to meet larger cooling loads.
[0136] The working process of the refrigeration system is as follows:
[0137] First, the second refrigeration module 2 is started. The high-temperature and high-pressure refrigeration vapor discharged from the second compressor 21 enters the condenser 22 for cooling and then enters the third heat exchanger 24.
[0138] The third heat exchanger 24 discharges medium-temperature and high-pressure refrigerant. Then, this part of the refrigerant is processed by the second pressure reducing component 201 and converted into low-temperature and low-pressure liquid refrigerant. Among them, part of the liquid refrigerant flows back into the third heat exchanger 24 through the fifth flow channel 28 and is converted into gaseous refrigerant by exchanging heat with the medium-temperature and high-pressure refrigerant output from the condenser 22. Then it flows back to the feed end of the second compressor 21.
[0139] Another portion of the low-temperature, low-pressure liquid refrigerant enters the second feed end of the first heat exchanger 12 along the main path (third flow channel 26). This portion of liquid refrigerant is also converted into gaseous refrigerant after heat exchange, and then flows back to the feed end of the second compressor 21, thus cycling.
[0140] After the second refrigeration module 2 is started, the first refrigeration module 1 is started. The high-temperature and high-pressure refrigeration vapor discharged from the first compressor 11 enters the first heat exchanger 12 and exchanges heat with the low-temperature and low-pressure liquid refrigerant discharged into the first heat exchanger 12 in the second refrigeration module 2, and then enters the second heat exchanger 14.
[0141] The second heat exchanger 14 discharges medium-temperature and high-pressure refrigerant. Then, this portion of refrigerant is processed by the first pressure reducing component 102 and converted into low-temperature and low-pressure liquid refrigerant. Among them, a portion of the liquid refrigerant flows back into the second heat exchanger 14 through the fifth pipe 19 and is converted into gaseous refrigerant by exchanging heat with the medium-temperature and high-pressure refrigerant output from the first heat exchanger 12. Then it flows back to the feed end of the first compressor 11.
[0142] Another portion of the low-temperature, low-pressure liquid refrigerant enters the evaporator 16 along the main path (third pipe 17). This portion of liquid refrigerant is also converted into gaseous refrigerant and then flows back to the feed end of the first compressor 11, thus creating a cycle.
[0143] It should be noted that the descriptions of high temperature and high pressure are only to indicate the differences in refrigerants at different stages. Taking temperature as an example, the above mentions high temperature, medium temperature and low temperature. The specific temperature range is not the innovation of this application. For further understanding, please refer to the prior art. For example, the specific temperature range of high temperature and high pressure refrigeration vapor can be referred to the existing cascade refrigeration system.
[0144] The explanation will be based on the first compressor 11 as an example, and the explanation will refer to the second compressor 21 as well:
[0145] First, due to the setting of the fifth pipe 19, a portion of the refrigerant output from the first heat exchanger 12 and another portion of the refrigerant output from the first heat exchanger 12 exchange heat through the second heat exchanger 14, which promotes the refrigerant that finally flows to the evaporator 16 to achieve sufficient subcooling, and avoids the generation of flash gas in this portion of refrigerant during subsequent pressure and temperature reduction, thereby ensuring the evaporation heat exchange effect and refrigeration efficiency.
[0146] Second, by using a portion of the refrigerant output from the first heat exchanger 12 to exchange heat with another portion of the refrigerant output from the first heat exchanger 12, the energy consumption of the refrigeration system is reduced and the operating cost of the refrigeration system is reduced by increasing the utilization of the refrigerant in the refrigeration system.
[0147] Third, the fifth pipe 19 and the sixth pipe 101 can form a bypass branch to balance the pressure at the intake end of the first compressor 11, avoiding the need to set up a separate bypass branch and reducing structural costs.
[0148] In this embodiment, the first voltage-reducing component 102 includes:
[0149] The first thermal expansion valve 1021 is located in the third pipeline 17;
[0150] The second thermal expansion valve 1022 is located in the fifth pipe 19;
[0151] The second step-down component 201 includes:
[0152] The third thermal expansion valve 2011 is located in the third flow channel 26;
[0153] The fourth thermal expansion valve 2012 is located in the fifth flow channel 28.
[0154] The following explanation uses the first voltage-reducing component 102 as an example:
[0155] On the one hand, thermal expansion valves are installed on both the third pipe 17 and the fifth pipe 19, which can independently control the flow rate of the third pipe 17 and the fifth pipe 19;
[0156] On the other hand, the connection point between the third pipe 17 and the fifth pipe 19 is not subject to many restrictions, allowing for flexible wiring layout in the refrigeration system.
[0157] Without the second thermal expansion valve 1022, the connection point between the third pipe 17 and the fifth pipe 19 would be significantly restricted, and the fluid would have to pass through the first thermal expansion valve 1021 before entering this connection point.
[0158] In this embodiment, the first cooling module 1 further includes:
[0159] The first control valve 103 is located in the third pipeline 17;
[0160] The second control valve 104 is located in the fifth pipeline 19;
[0161] The second refrigeration module 2 also includes:
[0162] The third control valve 202 is located in the third flow channel 26;
[0163] The fourth control valve 203 is located in the fifth flow channel 28.
[0164] The control valve in this application may be a solenoid valve.
[0165] Taking the first control valve 103 as an example, the second control valve 104, the third control valve 202 and the fourth control valve 203 are described in the same way: The first control valve 103 is used in conjunction with the first pressure reducing component 102. When the refrigeration system stops running, the first control valve 103 can quickly cut off the flow of refrigerant before the first pressure reducing component 102 acts, so as to protect the evaporator 16 and other equipment and achieve long-term stable operation of the refrigeration system.
[0166] In some embodiments, for similar control valves and pressure-reducing structures (such as the first control valve 103 and the first thermostatic expansion valve 1021), the fluid first passes through the control valve and then through the pressure-reducing structure along the fluid flow direction in the pipe or channel.
[0167] In this embodiment, the first cooling module 1 further includes:
[0168] The seventh pipe 105 is connected at both ends to the first pipe 13 and the feed end of the first compressor 11, respectively;
[0169] The fifth control valve 106 includes at least one control sub-valve disposed on the seventh pipeline 105;
[0170] The second refrigeration module 2 also includes:
[0171] The seventh flow channel 204 is connected at both ends to the first flow channel 23 and the feed end of the second compressor 21, respectively;
[0172] The sixth control valve 205 includes at least one control sub-valve disposed on the seventh flow channel 204.
[0173] The seventh pipe 105 and the fifth control valve 106 will be used as examples for explanation. The seventh flow channel 204 and the sixth control valve 205 will be explained in the same way.
[0174] First, the seventh pipe 105 can be directly connected to the feed end of the first compressor 11, or it can be indirectly connected to the feed end of the first compressor 11 (e.g., through the fourth pipe 18). This embodiment does not impose any restrictions.
[0175] Second, the fifth control valve 106 may include two control sub-valves, one of which is a solenoid valve and the other is a bypass valve. The solenoid valve can quickly cut off or connect the seventh pipeline 105, avoiding pressure fluctuations or other problems caused by the slow response speed of the bypass valve.
[0176] Third, the seventh pipe 105 forms a bypass branch, which is initially closed. When the pressure at the feed end of the first compressor 11 is too low, this bypass branch opens. This bypass branch can directly guide a portion of the high-temperature and high-pressure refrigeration vapor discharged from the discharge end of the first compressor 11 back to the feed end of the first compressor 11 to balance the pressure at the feed end of the first compressor 11.
[0177] In this embodiment, the sixth pipe 101 is connected to the feed end of the first compressor 11 through the fourth pipe 18;
[0178] The seventh pipe 105 is connected to the feed end of the first compressor 11 via the fourth pipe 18 or the sixth pipe 101;
[0179] The sixth flow channel 29 is connected to the feed end of the second compressor 21 through the fourth flow channel 27;
[0180] The seventh flow channel 204 is connected to the feed end of the second compressor 21 via the fourth flow channel 27 or the sixth flow channel 29.
[0181] The following example illustrates the connection of the sixth pipe 101 to the feed end of the first compressor 11 via the fourth pipe 18. Similar descriptions in this embodiment refer to this explanation: The sixth pipe 101 is not directly connected to the feed end of the first compressor 11. On the one hand, this shortens the length of the sixth pipe 101 to reduce structural costs; on the other hand, it avoids the messy layout of multiple pipes at the feed end of the first compressor 11, which would affect the difficulty of subsequent maintenance.
[0182] In some embodiments, the seventh pipe 105 is connected to the feed end of the first compressor 11 via the sixth pipe 101, and the seventh flow channel 204 is connected to the feed end of the second compressor 21 via the sixth flow channel 29.
[0183] In this embodiment, the fifth control valve 106 and the sixth control valve 205 each include two control sub-valves connected in series.
[0184] For a description of the control sub-valve, please refer to the above embodiment. This embodiment further clarifies the specific settings of the fifth control valve 106 and the sixth control valve 205.
[0185] In this embodiment, the first cooling module 1 further includes:
[0186] The eighth pipe 107 is connected at both ends to the fifth pipe 19 and the sixth pipe 101, respectively.
[0187] The seventh control valve 108 is located in the eighth pipeline 107;
[0188] The second refrigeration module 2 also includes:
[0189] The eighth flow channel 206 is connected at both ends to the fifth flow channel 28 and the sixth flow channel 29, respectively;
[0190] The eighth control valve 207 is located in the eighth flow channel 206.
[0191] For a description of the seventh control valve 108 and the eighth control valve 207, please refer to the description of similar control valves in the above embodiments. Taking the seventh control valve 108 as an example, the seventh control valve 108 is mainly set up to control the flow rate of the eighth pipeline 107.
[0192] Taking the eighth pipe 107 as an example, the eighth flow channel 206 is explained in the same way: the eighth pipe 107 is actually a bypass branch. The eighth pipe 107 is initially in a closed state. When the pressure at the feed end of the first compressor 11 is too high, the eighth pipe 107 is opened, and part of the liquid refrigerant that has entered the fifth pipe 19 flows directly through the eighth pipe 107 to the feed end of the first compressor 11 to balance the pressure at the feed end of the first compressor 11.
[0193] The feed end of the first compressor 11 may also experience excessively high temperature. In this case, low-temperature and low-pressure liquid refrigerant can be supplied to the feed end of the first compressor 11 through the sixth pipe 101 to cool it down and protect the first compressor 11 from damage. This replaces the method of continuously starting and stopping the first compressor 11 to achieve the cooling effect, thus saving energy.
[0194] Before the eighth pipe 107 is installed, the sixth pipe 101 only transports the gaseous refrigerant output from the second heat exchanger 14; after the eighth pipe 107 is installed, the liquid refrigerant and the gaseous refrigerant merge in the sixth pipe 101 and are transported to the feed end of the first compressor 11.
[0195] The location of the connection point between the eighth pipe 107 and the fifth pipe 19 in one case is shown in the attached figure, which will also be used as an example for illustration. The positions of each structure in this application can be adjusted according to the actual situation, and the settings in the attached figure can be regarded as the preferred solution.
[0196] In this embodiment, the first cooling module 1 further includes:
[0197] Storage container 109;
[0198] The ninth pipe 1001 is connected at both ends to the first pipe 13 and the inlet end of the storage container 109, respectively;
[0199] The ninth control valve 1002 is located in the ninth pipeline 1001;
[0200] The tenth pipe 1003 is connected at both ends to the discharge end of the storage container 109 and the inlet end of the first compressor 11, respectively.
[0201] The tenth control valve 1004 is located in the tenth pipeline 1003.
[0202] It should be noted that the first refrigeration module 1 is used for internal cooling of the equipment, and the second refrigeration module 2 exchanges heat with the first refrigeration module 1. Since the refrigerant pressure inside the first compressor 11 is at a high risk, the first compressor 11 is used in conjunction with the storage container 109.
[0203] This application does not limit the second compressor 21 to also being equipped with a storage container 109, and the configuration method is the same as that in this embodiment.
[0204] When the pressure in the main circuit of the first refrigeration module 1 is higher than the set pressure, the refrigerant can flow into the storage container 109 to protect the safety of the refrigeration system; when the pressure is lower than the set pressure, the refrigerant can flow from the storage container 109 to the first compressor 11.
[0205] In some embodiments, the ninth control valve 1002 is configured as an energy regulating valve.
[0206] In some embodiments, the tenth control valve 1004 is configured as a one-way valve, which only allows fluid to flow from the storage container 109 to the first compressor 11, thereby preventing refrigerant that should flow into the feed end of the first compressor 11 from flowing into the storage container 109.
[0207] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.
Claims
1. A waste heat recovery cascade refrigeration system, characterized in that: Includes a first refrigeration module and a second refrigeration module; The first refrigeration module includes: First compressor; The first heat exchanger has its first feed end connected to the discharge end of the first compressor via a first pipe. The second heat exchanger has its first feed end connected to the first discharge end of the first heat exchanger via a second pipe. The evaporator is connected to the first discharge end of the second heat exchanger via a third pipe and to the feed end of the first compressor via a fourth pipe. The fifth pipe is connected at both ends to the third pipe and the second feed end of the second heat exchanger, respectively. The sixth pipe is connected at both ends to the second discharge end of the second heat exchanger and the feed end of the first compressor, respectively. The first pressure-reducing component shall be installed at least in the third pipeline; The second refrigeration module includes: Second compressor; The condenser has its inlet end connected to the outlet end of the second compressor via a first flow channel. The third heat exchanger has its first feed end connected to the condenser's discharge end via a second flow channel; The third flow channel is connected at both ends to the first discharge end of the third heat exchanger and the second inlet end of the first heat exchanger, respectively. The fourth flow channel is connected at both ends to the second discharge end of the first heat exchanger and the inlet end of the second compressor, respectively. The fifth flow channel is connected at both ends to the second feed end of the third flow channel and the third heat exchanger, respectively. The sixth flow channel is connected at both ends to the second discharge end of the third heat exchanger and the inlet end of the second compressor, respectively. The second pressure-reducing component is located at least in the third flow channel.
2. The waste heat recovery cascade refrigeration system according to claim 1, characterized in that: The first step-down component includes: A first thermal expansion valve is located in the third pipeline; A second thermal expansion valve is located in the fifth pipeline; The second step-down component includes: A third thermal expansion valve is located in the third flow channel; The fourth thermal expansion valve is located in the fifth flow channel.
3. The waste heat recovery cascade refrigeration system according to claim 1, characterized in that: The first refrigeration module also includes: A first control valve is located in the third pipeline; The second control valve is located in the fifth pipeline; The second refrigeration module also includes: A third control valve is located in the third flow channel; The fourth control valve is located in the fifth flow channel.
4. The waste heat recovery cascade refrigeration system according to claim 1, characterized in that: The first refrigeration module also includes: The seventh pipe is connected at both ends to the first pipe and the feed end of the first compressor, respectively. The fifth control valve includes at least one control sub-valve located on the seventh pipeline; The second refrigeration module also includes: The seventh flow channel is connected at both ends to the first flow channel and the feed end of the second compressor, respectively. The sixth control valve includes at least one control sub-valve disposed on the seventh flow channel.
5. The waste heat recovery cascade refrigeration system according to claim 4, characterized in that: The sixth pipe is connected to the feed end of the first compressor via the fourth pipe; The seventh pipe is connected to the feed end of the first compressor via the fourth pipe or the sixth pipe; The sixth flow channel is connected to the feed end of the second compressor through the fourth flow channel; The seventh flow channel is connected to the feed end of the second compressor via the fourth flow channel or the sixth flow channel.
6. The waste heat recovery cascade refrigeration system according to claim 4, characterized in that: The fifth control valve and the sixth control valve each include two control sub-valves connected in series.
7. The waste heat recovery cascade refrigeration system according to claim 1, characterized in that: The first refrigeration module also includes: The eighth pipe is connected at both ends to the fifth pipe and the sixth pipe, respectively; The seventh control valve is located in the eighth pipeline; The second refrigeration module also includes: The eighth flow channel is connected at both ends to the fifth flow channel and the sixth flow channel, respectively. The eighth control valve is located in the eighth flow channel.
8. The waste heat recovery cascade refrigeration system according to claim 1, characterized in that: The first refrigeration module also includes: Storage containers; The ninth pipe is connected at both ends to the first pipe and the inlet of the storage container, respectively. The ninth control valve is located in the ninth pipeline; The tenth pipe is connected at both ends to the discharge end of the storage container and the inlet end of the first compressor, respectively. The tenth control valve is located in the tenth pipeline.