Shell tube evaporator and refrigerating unit
By adding heat exchange tubes and baffles inside the shell-and-tube evaporator, combined with a spiral groove tube design, the problems of insufficient subcooling and liquid carry-in during compressor suction in flooded evaporators are solved, achieving a more efficient refrigeration cycle and optimized energy consumption.
Patent Information
- Application Number
- CN202520626001.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2035-04-03
AI Technical Summary
In existing flooded evaporators, the liquid discharged from the condenser directly enters the expansion valve, resulting in reduced system energy efficiency, insufficient subcooling, and a risk of liquid being carried into the compressor suction.
Heat exchange tubes are added inside the shell and tube evaporator. The liquid from the pre-condenser is first cooled through the heat exchange tubes. A baffle plate is installed inside the evaporator to prevent water vapor from entering. Combined with the spiral groove tube design to promote turbulent heat transfer, secondary cooling is then carried out in the economizer.
It improves the subcooling of the liquid outlet, reduces the risk of liquid carryover in the compressor suction, optimizes the refrigeration cycle process, and reduces energy consumption and costs.
Smart Images
Figure CN223954425U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of refrigeration equipment, in particular to a shell-and-tube evaporator and a refrigeration unit using the same. BACKGROUND
[0002] Evaporators are commonly used heat exchange devices in refrigeration equipment, and full-liquid evaporators are one of them. Full-liquid evaporators have advantages of high energy efficiency, large cooling capacity, and excellent low-temperature adaptability, and thus play an important role in industrial refrigeration and large air conditioning systems.
[0003] In the prior art, full-liquid evaporators have many problems, for example, the liquid outlet of the condenser directly enters the expansion valve, which reduces the system energy efficiency and causes insufficient supercooling. CONTENT OF THE UTILITY MODEL
[0004] Therefore, the present application provides a shell-and-tube evaporator which can avoid the problem of insufficient supercooling. The specific structure includes a shell, the surface of which is provided with an evaporator inlet and an evaporator outlet; a heat exchange tube, which is arranged in the shell and includes a heat exchange tube inlet and a heat exchange tube outlet arranged on the surface of the shell; and a coil pipe, which is arranged in the shell and below the heat exchange tube.
[0005] With the above specific structure, the heat exchange tube is added above the coil pipe in the shell-and-tube evaporator, and the liquid outlet of the front condenser is first cooled in the shell-and-tube evaporator through the heat exchange tube, which can increase the supercooling degree of the liquid outlet. In addition, when the gaseous refrigerant flows through the heat exchange tube in the shell-and-tube evaporator, it performs convective heat exchange with the high-temperature liquid refrigerant in the heat exchange tube. After heat exchange, the temperature of the gaseous refrigerant flowing to the evaporator outlet is increased, and the high-temperature gaseous refrigerant flowing to the rear compressor increases the temperature of the compressor, thereby reducing the risk of liquid entrainment in the suction of the compressor.
[0006] As a possible implementation manner, a liquid blocking plate is arranged between the heat exchange tube and the coil pipe.
[0007] With the above possible implementation manner, the liquid blocking plate is used to prevent water vapor on the coil pipe side from entering the heat exchange tube side, thereby reducing the risk of liquid entrainment in the suction of the compressor.
[0008] As a possible implementation manner, the heat exchange tube is bent and arranged horizontally in two layers.
[0009] As a possible implementation manner, the coil pipe includes a water outlet and a water inlet, the water outlet and the water inlet are arranged on the surface of the shell, and the water outlet and the water inlet are connected with a cold water system.
[0010] As a possible implementation, the coil pipe includes three groups of double-row coil pipes arranged in vertical direction, each group of coil pipes arranged horizontally and having a gap between them.
[0011] As a possible implementation, the shell is in the shape of a cylinder, and the shell is horizontally placed with a semi-circular cover arranged at each of the two top ends for sealing.
[0012] As a possible implementation, the evaporator inlet is arranged at the lower end of the shell, and the evaporator outlet is arranged at the upper end of the shell.
[0013] As a possible implementation, the heat exchange pipe is a spiral groove pipe.
[0014] With the above possible implementation, the spiral groove in the spiral groove pipe can destroy the fluid boundary layer, so that the fluid refrigerant generates turbulent flow, thereby increasing the convective heat transfer coefficient and strengthening the heat exchange effect.
[0015] A refrigeration unit includes the shell-and-coil evaporator as described above; a condenser including a condenser liquid outlet and a condenser air inlet, the condenser liquid outlet being connected to the heat exchange pipe inlet through a pipeline; a main expansion valve including a main expansion valve inlet and a main expansion valve outlet, the main expansion valve inlet being connected to the heat exchange pipe outlet through a first pipeline, and the main expansion valve outlet being connected to the evaporator inlet through a pipeline; and a compressor including a first air inlet, a second air inlet and a compressor air outlet, the first air inlet being connected to the evaporator outlet through a pipeline, and the compressor air outlet being connected to the condenser air inlet through an exhaust pipe.
[0016] As a possible implementation, an economizer is arranged on the first pipeline, and the economizer includes: a main circuit including a main circuit liquid inlet and a main circuit liquid outlet, the main circuit liquid inlet being connected to the heat exchange pipe outlet through a pipeline, and the main circuit liquid outlet being connected to the main expansion valve inlet through a pipeline; and a flash circuit including a flash circuit inlet and a flash circuit outlet, the flash circuit inlet being connected to the main circuit liquid outlet through a second pipeline, and the flash circuit outlet being connected to the second air inlet through a pipeline, and an economizer expansion valve being arranged on the second pipeline.
[0017] With the above possible implementation, the refrigerant flowing out of the heat exchange pipe flows into the main circuit of the economizer and exchanges heat with the refrigerant expanded into a gaseous state by the economizer expansion valve in the flash circuit, thereby completing the second cooling, and the condenser liquid is first cooled in the heat exchange pipe and then cooled in the economizer, which can increase the supercooling degree of the liquid outlet, reduce the heat exchange area of the economizer, and thereby reduce the cost. BRIEF DESCRIPTION OF DRAWINGS
[0018] The various technical features of the present application and the relationships between them will be further illustrated below with reference to the accompanying drawings. The drawings are exemplary, some technical features are not shown in actual proportion, and some technical features in the drawings can be omitted, which are conventional in the technical field to which the present application belongs and are not essential for understanding and implementing the present application, or additional technical features are shown, which are not essential for understanding and implementing the present application. That is, the combination of various technical features shown in the drawings is not used to limit the present application. In addition, the same reference signs refer to the same contents throughout the present application. The specific drawings are as follows:
[0019] Figure 1 A schematic diagram of the refrigeration unit according to an embodiment of the present application;
[0020] Figure 2 A schematic diagram of the refrigeration unit according to an embodiment of the present application after installing an economizer;
[0021] Figure 3 A front view of the shell-and-tube evaporator in the refrigeration unit according to an embodiment of the present application;
[0022] Figure 4 A sectional view of the shell-and-tube evaporator in the refrigeration unit according to an embodiment of the present application;
[0023] Figure 5 A sectional view of the economizer in the refrigeration unit according to an embodiment of the present application.
[0024] Legend of reference signs: 10 - condenser; 20 - shell-and-tube evaporator; 21 - heat exchange tube; 211 - heat exchange tube inlet; 212 - heat exchange tube outlet; 22 - coil pipe; 221 - water inlet; 222 - water outlet; 23 - liquid blocking plate; 24 - evaporator inlet; 25 - evaporator outlet; 30 - main expansion valve; 40 - compressor; 41 - first gas inlet; 42 - second gas inlet; 50 - fan; 60 - first pipeline; 70 - economizer; 71 - main circuit; 72 - flash circuit; 80 - second pipeline; 90 - economizer expansion valve. DETAILED DESCRIPTION
[0025] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.
[0026] The present application provides a shell-and-tube evaporator, such as Figure 3As shown, the shell-and-tube evaporator 20 comprises a shell. The shell surface is provided with an evaporator inlet 24 and an evaporator outlet 25. A liquid baffle 23 is arranged in the shell, which divides the shell into an upper layer and a lower layer. The liquid baffle 23 can play a role in isolating water vapor, and is used to isolate the upper layer and the lower layer area to prevent water vapor from entering the upper layer area. The upper layer is provided with heat exchange tubes 21. The heat exchange tubes 21 comprise a heat exchange tube inlet 211 and a heat exchange tube outlet 212, which are arranged on the surface of the shell. The lower layer is provided with a coil 22. The coil 22 comprises a water outlet 222 and a water inlet 221, which are arranged on the surface of the shell and connected with the cold water system.
[0027] In this embodiment, as shown in Figure 3 The shell is in the shape of a cylinder and is placed horizontally, and semi-circular covers are arranged at the two top ends to seal them. In other embodiments, other shapes of the shell can also be used, such as a cylinder placed vertically or a cuboid.
[0028] In this embodiment, as shown in Figure 3 The evaporator inlet 24 is arranged at the lower end of the shell, and the evaporator outlet 25 is arranged at the upper end of the shell. The liquid refrigerant enters the shell-and-tube evaporator 20 from the evaporator inlet 24 at the lower end and evaporates into gaseous refrigerant at the coil 22. According to the principle of thermal convection of hot air rising, the gaseous refrigerant can rise smoothly and flow out from the evaporator outlet 25 at the upper end. In other embodiments, the evaporator inlet 24 and the evaporator outlet 25 can also be installed at other positions of the shell. For example, the evaporator inlet 24 and the evaporator outlet 25 can be installed at both ends of the shell.
[0029] In this embodiment, as shown in Figure 4 The heat exchange tubes 21 are bent and arranged horizontally in two layers. In other embodiments, the heat exchange tubes 21 can also be arranged in other ways, such as bent into two, three, four, or more layers.
[0030] In this embodiment, as shown in Figure 4 The coil 22 comprises three groups of double-row coils 22 arranged in a vertical direction, and each group of coils 22 is arranged horizontally with a gap between them. In other embodiments, the coil 22 can also be arranged in other ways, such as four groups, five groups of double-row or triple-row coils 22, etc.
[0031] In this embodiment, the heat exchange tubes 21 are spiral grooved tubes. The spiral grooves in the spiral grooved tubes can destroy the fluid boundary layer, causing the fluid refrigerant to produce turbulent flow, thereby increasing the convective heat transfer coefficient and enhancing the heat exchange effect. In other embodiments, other types of heat exchange tubes 21 can also be used, such as corrugated tubes, finned tubes, micro-channel tubes, etc.
[0032] In summary, the heat exchange tube 21 is added above the coil 22 in the shell and tube evaporator 20, the liquid from the pre-condenser is cooled in the shell and tube evaporator 20 by the heat exchange tube 21, and the supercooling degree of the liquid is increased. Meanwhile, the gaseous refrigerant flows through the heat exchange tube 21 in the shell and tube evaporator 20, and the gaseous refrigerant is in counterflow heat exchange with the high-temperature liquid refrigerant in the heat exchange tube 21. After the heat exchange, the temperature of the gaseous refrigerant flowing to the evaporator outlet 25 is increased, the temperature of the post-compressor is increased, and the risk of liquid entrainment of the post-compressor suction is reduced.
[0033] The application also provides a refrigeration unit, as shown in the figure, which comprises a shell and tube evaporator 20, a condenser 10, a main expansion valve 30 and a compressor 40. As shown in the figure, the refrigeration unit can also be provided with an economizer 70 for secondary cooling of the refrigerant. Figure 1 Figure 2 The application also provides a refrigeration unit, as shown in the figure, which comprises a shell and tube evaporator 20, a condenser 10, a main expansion valve 30 and a compressor 40. As shown in the figure, the refrigeration unit can also be provided with an economizer 70 for secondary cooling of the refrigerant.
[0034] The condenser 10, as shown in the figure, comprises a condenser liquid outlet and a condenser air inlet. The condenser liquid outlet is connected to the heat exchange tube inlet 211 through a pipeline. The liquid from the condenser 10 is cooled in the shell and tube evaporator 20 by the heat exchange tube 21, and the supercooling degree of the liquid is increased. The condenser 10 is provided with a fan 50. Figure 1 2 The main expansion valve 30, as shown in the figure, comprises a main expansion valve inlet and a main expansion valve outlet. The main expansion valve inlet is connected to the heat exchange tube outlet 212 through a first pipeline 60, and the main expansion valve outlet is connected to the evaporator inlet 24 through a pipeline.
[0035] The main expansion valve 30, as shown in the figure, comprises a main expansion valve inlet and a main expansion valve outlet. The main expansion valve inlet is connected to the heat exchange tube outlet 212 through a first pipeline 60, and the main expansion valve outlet is connected to the evaporator inlet 24 through a pipeline. Figure 1 In this embodiment, the main expansion valve 30 is an electronic expansion valve. In other embodiments, other types of expansion valves can also be used, such as thermal expansion valves, capillary tubes, float expansion valves, etc.
[0036] The compressor 40, as shown in the figure, comprises a first air inlet 41, a second air inlet 42 and a compressor air outlet. The first air inlet 41 is connected to the evaporator outlet 25 through a pipeline, and the compressor air outlet is connected to the condenser air inlet through an exhaust pipe.
[0037] Figure 2 In some embodiments, as shown in the figure, the first pipeline 60 is provided with an economizer 70. The economizer 70 comprises a main circuit 71 and a flash circuit 72.
[0038] The main circuit 71, as shown in the figure, comprises a main circuit inlet 711, a main circuit outlet 712 and a main circuit bypass 713. The main circuit inlet 711 is connected to the main expansion valve outlet through a pipeline, the main circuit outlet 712 is connected to the evaporator inlet 24 through a pipeline, and the main circuit bypass 713 is connected to the main circuit outlet 712 through a pipeline. Figure 2 The flash circuit 72, as shown in the figure, comprises a flash circuit inlet 721 and a flash circuit outlet 722. The flash circuit inlet 721 is connected to the main circuit bypass 713 through a pipeline, and the flash circuit outlet 722 is connected to the evaporator inlet 24 through a pipeline.
[0039] Figure 5 As shown, the main circuit 71 includes a main circuit inlet and a main circuit outlet. The main circuit inlet is connected to the heat exchange tube outlet 212 via a pipeline, and the main circuit outlet is connected to the main expansion valve 30 inlet via a pipeline.
[0040] Among them, such as Figure 5 As shown, the flash circuit 72 includes a flash circuit inlet and a flash circuit outlet. The flash circuit inlet is connected to the main circuit liquid outlet via a second pipeline 80, and the flash circuit outlet is connected to the second air inlet 42 via a pipeline. An economizer expansion valve 90 is installed on the second pipeline 80. A portion of the liquid refrigerant is diverted through the second pipeline 80 and throttled and depressurized by the economizer expansion valve 90 to form a low-temperature gaseous refrigerant. The low-temperature gaseous refrigerant enters the flash circuit 72 to exchange heat with the high-temperature liquid refrigerant in the main circuit 71. The low-temperature gaseous refrigerant flowing out of the flash circuit outlet flows through the pipeline to the second air inlet 42 and into the compressor 40, which can replenish the compressor with gas, thereby optimizing the compression process and reducing power consumption.
[0041] In this embodiment, the economizer expansion valve 90 is an electronic expansion valve. Alternatively, in other embodiments, other types of expansion valves may be used, such as thermostatic expansion valves, capillary expansion valves, float expansion valves, etc.
[0042] The following describes the pathway of the refrigerant in the refrigeration cycle of the refrigeration unit involved in the embodiments of this application.
[0043] First, the high-temperature liquid refrigerant flowing from the condenser 10 enters the heat exchange tube 21 in the shell-and-tube evaporator 20 through a pipeline. The high-temperature liquid refrigerant inside the heat exchange tube 21 and the low-temperature gaseous refrigerant outside the heat exchange tube 21 undergo convective heat exchange, thus completing the first cooling. After the first cooling, the high-temperature liquid refrigerant flows out of the heat exchange tube 21 and enters the economizer 70 for a second cooling to increase the subcooling. The liquid refrigerant, cooled twice, enters the shell-and-tube evaporator 20 through the main expansion valve 30. Heat exchange occurs at the lower coil 22 of the shell-and-tube evaporator 20, transforming it into a low-temperature gaseous refrigerant. Then, the low-temperature gaseous refrigerant passes through the baffle plate 23 and exchanges heat with the high-temperature liquid refrigerant in the heat exchange tube 21. The heated low-temperature gaseous refrigerant enters the compressor 40 through the evaporator outlet 25. The compressed low-temperature gaseous refrigerant enters the condenser 10 through the exhaust pipe, thus completing a refrigeration cycle and achieving liquid cooling (increasing the liquid subcooling of the condenser 10) and gas heating (increasing the suction superheat of the compressor 40).
[0044] In summary, the condenser 10, the economizer 70, the main expansion valve 30, the shell and tube evaporator 20 and the compressor 40 connected by pipelines meet the refrigeration cycle, and the refrigeration unit related to the embodiments of the present application increases the heat exchange pipe 21 in the upper layer of the shell and tube evaporator 20. The condenser 10 liquid first passes through the heat exchange pipe 21 in the shell and tube evaporator 20 for primary cooling, which can increase the supercooling degree of the condenser 10 liquid. In addition, under special working conditions or immature control strategy, the liquid baffle 23 at the top of the evaporator may fail, and the compressor 40 may carry liquid refrigerant in the return gas, causing liquid strike of the compressor 40. When the refrigerant gas flows through the heat exchange pipe 21 in the shell and tube evaporator 20, it exchanges heat with the high-temperature liquid refrigerant in the heat exchange pipe 21. After heat exchange, the refrigerant gas flowing to the evaporator outlet 25 has a higher temperature, which increases the suction temperature of the compressor 40, thereby reducing the risk of liquid suction of the compressor 40. The refrigerant flowing out of the heat exchange pipe 21 flows into the main circuit 71 of the economizer 70, and exchanges heat with the refrigerant in the flash circuit 72 which is expanded to gas state by the economizer expansion valve 90, thereby completing the second cooling. The condenser 10 liquid first undergoes primary cooling in the heat exchange pipe 21, and then undergoes secondary cooling in the economizer 70, which can increase the supercooling degree of the liquid and reduce the heat exchange area of the economizer 70, thereby reducing the cost.
[0045] The term "comprising" as used in the full text of the present application should not be interpreted as limiting to the listed items; it does not exclude other structural elements or steps.
[0046] It can be understood that those skilled in the art can combine the features mentioned in one or more embodiments mentioned throughout the present application with the features in other embodiments in any appropriate manner to implement the present application.
[0047] It should be noted that the above is only the preferred embodiment of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the technical concept of the present application, which all belong to the protection scope of the present application.
Claims
1. A shell and tube evaporator characterized by, The application relates to a shell-tube evaporator. The shell is provided with an evaporator inlet and an evaporator outlet on the surface. The heat exchange pipe is arranged in the shell and comprises a heat exchange pipe inlet and a heat exchange pipe outlet arranged on the surface of the shell. The disc pipe is arranged in the shell and below the heat exchange pipe.
2. The shell and tube evaporator of claim 1, wherein, A liquid blocking plate is arranged between the heat exchange pipe and the disc pipe.
3. The shell and tube evaporator of claim 1, wherein, The heat exchange pipe is bent and arranged in two layers horizontally.
4. The shell and tube evaporator of claim 1, wherein, The disc pipe comprises a water outlet and a water inlet arranged on the surface of the shell and connected with a cold water system.
5. The shell and tube evaporator of claim 1 or 4, wherein, The disc pipe comprises three groups of double-row disc pipes arranged in a vertical direction, each group of disc pipes being arranged horizontally and having a gap therebetween.
6. The shell and tube evaporator of claim 1, wherein, The shell is in the shape of a cylinder and horizontally placed, and two semicircular cover bodies are arranged on the top ends of the shell to seal the shell.
7. The shell and tube evaporator of claim 6, wherein, The evaporator inlet is arranged at the lower end of the shell, and the evaporator outlet is arranged at the upper end of the shell.
8. The shell and tube evaporator of claim 1 or 3, wherein, The heat exchange pipe is a spiral groove pipe.
9. A refrigeration unit characterized by, The application relates to a shell-tube evaporator. The condenser comprises a condenser liquid outlet and a condenser gas inlet, the condenser liquid outlet is connected with the heat exchange pipe inlet through a pipeline. The main expansion valve comprises a main expansion valve inlet and a main expansion valve outlet, the main expansion valve inlet is connected with the heat exchange pipe outlet through a first pipeline, and the main expansion valve outlet is connected with the evaporator inlet through a pipeline. The compressor comprises a first gas inlet, a second gas inlet and a compressor gas outlet, the first gas inlet is connected with the evaporator outlet through a pipeline, and the compressor gas outlet is connected with the condenser gas inlet through an exhaust pipe. The first pipeline is provided with an economizer, which comprises:
10. The refrigeration unit of claim 9, wherein, The main loop comprises a main loop liquid inlet and a main loop liquid outlet, the main loop liquid inlet is connected with the heat exchange pipe outlet through a pipeline, and the main loop liquid outlet is connected with the main expansion valve inlet through a pipeline. The flash loop comprises a flash loop inlet and a flash loop outlet, the flash loop inlet is connected with the main loop liquid outlet through a second pipeline, the flash loop outlet is connected with the second gas inlet through a pipeline, and the second pipeline is provided with an economizer expansion valve.