Evaporator and refrigerating system
By designing a gas-liquid separator and distributor, the problem of diminishing heat exchange efficiency in falling film evaporators was solved, resulting in a reduction in refrigerant charge and cost, and improved heat exchange efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SICHUAN LENGFENG INTELLIGENT TECHNOLOGY CO LTD
- Filing Date
- 2025-05-21
- Publication Date
- 2026-04-21
AI Technical Summary
In existing falling film evaporators, the lower tube bundle cannot directly contact the sprayed liquid droplets, resulting in a gradual decrease in heat exchange efficiency at each layer, and a relatively large amount of refrigerant is required.
A gas-liquid separator is used to separate the gas and liquid refrigerants. The liquid refrigerant is evenly distributed onto the heat exchange tubes through the first distributor, while the gaseous refrigerant mixes with the liquid at the bottom, reducing the amount of refrigerant used. The stability of the gas-liquid flow is controlled by the second distributor.
To improve heat exchange efficiency with the same refrigerant volume, reduce refrigerant charge, simplify structure, and reduce cost.
Smart Images
Figure CN224151202U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heat exchanger technology, and in particular to an evaporator and refrigeration system. Background Technology
[0002] Both flooded and falling film evaporators are shell-and-tube evaporator types widely used in chiller units. For the same dimensions, falling film evaporators generally require less refrigerant than flooded evaporators. However, due to the tube bundle arrangement, the tube bundles at the bottom of the falling film evaporator cannot directly contact the sprayed liquid droplets; they can only contact the residual liquid remaining after evaporation from the upper tube bundles. Therefore, the heat exchange efficiency of the tube bundle decreases progressively downwards. To improve the heat exchange efficiency of the lower tube bundles, the refrigerant flow rate in the shell side is generally increased to create liquid accumulation at the bottom of the shell, immersing the lower tube bundles in the liquid. However, this approach still suffers from the problem of requiring a relatively large refrigerant charge.
[0003] Therefore, there is an urgent need to propose an evaporator and refrigeration system to solve the above-mentioned technical problems. Utility Model Content
[0004] According to one aspect of the present invention, an evaporator is provided that, while ensuring heat exchange effect, requires less refrigerant and has a simple structure and low cost.
[0005] To achieve this objective, the present invention adopts the following technical solution:
[0006] Evaporator, including:
[0007] The housing has a liquid inlet and an exhaust port at the top, and a gas inlet at the bottom.
[0008] A gas-liquid separator is provided, in which two-phase refrigerant enters the gas-liquid separator through its inlet, and the liquid outlet of the gas-liquid separator is connected to the liquid inlet to deliver the liquid refrigerant into the housing. The gas outlet of the gas-liquid separator is connected to the gas inlet to deliver the gaseous refrigerant into the housing.
[0009] Multiple heat exchange tubes are spaced apart inside the housing;
[0010] A first distributor is disposed within the housing and above the plurality of heat exchange tubes, the first distributor being configured to distribute liquid refrigerant onto the plurality of heat exchange tubes.
[0011] Optionally, a second distributor is provided below the plurality of heat exchange tubes within the housing, the second distributor being used to distribute gaseous refrigerant.
[0012] Optionally, the inlet of the gas-liquid separator is connected to a first pipeline, the first pipeline is equipped with a first electronic expansion valve, and the housing is equipped with a liquid level detection element.
[0013] Optionally, the liquid outlet and the liquid inlet are connected by a second pipeline, the second pipeline being equipped with a second electronic expansion valve, and the gas outlet and the gas inlet are directly connected by a third pipeline.
[0014] Optionally, the interior of the shell is divided into a falling film heat exchange zone and a full liquid heat exchange zone, with the falling film heat exchange zone located in the upper part of the shell and the full liquid heat exchange zone located in the lower part of the shell;
[0015] The multiple heat exchange tubes are divided into falling film heat exchange tube bundles and full liquid heat exchange tube bundles. The falling film heat exchange tube bundles are arranged in the falling film heat exchange zone and located below the first distributor, while the full liquid heat exchange tube bundles are arranged in the full liquid heat exchange zone.
[0016] Optionally, baffles are provided on opposite sides of the first distributor, the baffles are inclined outward, and the falling film heat exchange tube bundle is located between the two baffles.
[0017] Optionally, the first distributor includes at least one first distribution plate, and the first distribution plate is provided with a plurality of first through holes.
[0018] Optionally, the second distributor includes at least one second distribution plate, which has a plurality of second through holes.
[0019] Optionally, a gas-liquid filter screen is provided at the exhaust port.
[0020] According to another aspect of the present invention, the present invention also provides a refrigeration system, including a compressor, a condenser, a throttling valve, and an evaporator as described in any of the above technical solutions, wherein the outlet of the compressor is connected to the inlet of the condenser, the outlet of the condenser is connected to the inlet of the throttling valve, the outlet of the throttling valve is connected to the inlet of the gas-liquid separator, and the exhaust port of the housing is connected to the inlet of the compressor.
[0021] The beneficial effects of this utility model are:
[0022] This invention provides an evaporator, comprising a shell, a gas-liquid separator, multiple heat exchange tubes, and a first distributor. The evaporator uses the gas-liquid separator to separate the gas and liquid phases of the refrigerant. The liquid refrigerant is then transported to the top of the evaporator and distributed to the multiple heat exchange tubes via the first distributor for heat exchange. The gaseous refrigerant is introduced to the bottom of the shell. Liquid refrigerant dripping from the top of the shell mixes with the gaseous refrigerant at the bottom, increasing the cavitation rate of the refrigerant at the bottom. This significantly reduces the overall refrigerant charge for the same refrigerant volume, saving refrigerant. Furthermore, the structure is simple and the cost is low.
[0023] By incorporating a gas-liquid separator, liquid refrigerant can be sprayed onto the heat exchange tubes, resulting in higher heat exchange efficiency compared to the existing technology that uses a two-phase gas-liquid refrigerant. Furthermore, since the sprayed refrigerant is liquid, a liquid distributor can be used as the first distributor, offering higher distribution uniformity, simpler control, and lower maintenance costs compared to the existing technology that requires a two-phase distributor.
[0024] This invention also provides a refrigeration system, including a compressor, a condenser, a throttling valve, and the aforementioned evaporator. Because this refrigeration system uses the aforementioned evaporator, it requires less refrigerant, reducing refrigerant costs, and also offers higher refrigeration efficiency. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.
[0026] Figure 1 This is a cross-sectional view of the evaporator provided in an embodiment of the present invention;
[0027] Figure 2 This is a front view of the evaporator provided in an embodiment of the present invention (showing the interior of the casing);
[0028] Figure 3 This is a schematic diagram of the refrigeration system provided in an embodiment of the present invention.
[0029] In the picture:
[0030] 100. Evaporator; 110. Shell; 101. Falling film heat exchange zone; 102. Flooded heat exchange zone; 111. Liquid inlet; 112. Exhaust port; 113. Gas inlet; 120. Gas-liquid separator; 121. Liquid outlet; 122. Gas outlet; 130. Heat exchange tube; 140. First distributor; 141. Baffle plate; 150. Second distributor; 160. First pipeline; 170. First electronic expansion valve; 180. Second pipeline; 190. Second electronic expansion valve; 1000. Third pipeline;
[0031] 200, compressor; 300, condenser; 400, throttle valve. Detailed Implementation
[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not the entire structure.
[0033] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0035] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.
[0036] This embodiment provides an evaporator that, while ensuring heat exchange efficiency, requires a small amount of refrigerant and has a simple structure and low cost.
[0037] Specifically, such as Figure 1 and Figure 2 As shown, the evaporator 100 includes a shell 110, a gas-liquid separator 120, multiple heat exchange tubes 130, and a first distributor 140.
[0038] The housing 110 has a liquid inlet 111 and an exhaust port 112 at its top, and a gas inlet 113 at its bottom. The liquid outlet 121 of the gas-liquid separator 120 is connected to the liquid inlet 111, and the gas outlet 122 of the gas-liquid separator 120 is connected to the gas inlet 113. Multiple heat exchange tubes 130 are spaced apart within the housing 110. A first distributor 140 is disposed within the housing 110 and above the multiple heat exchange tubes 130, and is configured to distribute liquid refrigerant onto the multiple heat exchange tubes 130.
[0039] The working principle of the evaporator 100 is as follows:
[0040] See also Figure 1 The gas-liquid two-phase refrigerant enters the gas-liquid separator 120 through the inlet. Under the action of the gas-liquid separator 120, the gaseous refrigerant and the liquid refrigerant are separated. The separated gaseous refrigerant and liquid refrigerant are discharged from the gas outlet 122 and the liquid outlet 121 of the gas-liquid separator 120, respectively.
[0041] Liquid refrigerant discharged from the liquid outlet 121 of the gas-liquid separator 120 enters the housing 110 through the liquid inlet 111. It is then evenly distributed to multiple heat exchange tubes 130 by the first distributor 140. Under gravity, the liquid refrigerant flows downwards along the tube walls of the heat exchange tubes 130, forming a uniform liquid film. After exchanging heat with the heat exchange tubes 130, the liquid film rapidly evaporates, forming gaseous refrigerant which is discharged from the exhaust port 112 at the top of the housing 110. Unevaporated refrigerant continues to drip downwards, contacting the lower heat exchange tubes 130. Finally, some of the liquid refrigerant accumulates at the bottom of the housing 110, forming a liquid pool. The heat exchange tubes 130 at the bottom of the housing 110 are immersed in this liquid pool, creating a flooded heat exchange system. This ensures the heat exchange efficiency of all heat exchange tubes 130. Furthermore, the evaporator 100 can spray the heat exchange tube bundle 130 with liquid refrigerant, which results in higher heat exchange efficiency compared to the use of two-phase refrigerant in the prior art. Simultaneously, since the sprayed refrigerant is liquid, the first distributor 140 can be a liquid distributor, which offers higher uniformity of distribution, simpler control, and lower maintenance costs compared to the two-phase distributor required in the prior art.
[0042] The gaseous refrigerant discharged from the gas outlet 122 of the gas-liquid separator 120 enters the housing 110 through the gas inlet 113 at the bottom of the housing 110. The gaseous refrigerant mixes with the accumulated liquid at the bottom of the housing 110. Since the gaseous refrigerant occupies a part of the volume, the amount of refrigerant used is reduced and the refrigerant cost is lowered under the same refrigerant volume.
[0043] Further, see also Figure 1 Inside the housing 110, a second distributor 150 is provided below multiple heat exchange tubes 130. The second distributor 150 is used to distribute gaseous refrigerant. By setting the second distributor 150, the liquid static pressure and gas flow rate at the bottom of the housing 110 can be controlled, preventing the liquid accumulated at the bottom of the housing 110 from being sprayed upward in a columnar shape under the action of the gaseous refrigerant.
[0044] It is understandable that the uniformity of liquid refrigerant spray can be controlled by controlling the pressure drop of the first distributor 140, and the stability and heat exchange efficiency of the gas-liquid two-phase flow at the bottom of the casing 110 can be controlled by controlling the pressure drop of the second distributor 150.
[0045] It is worth noting that in this embodiment, the gas-liquid separator 120 is arranged outside the housing 110. In other embodiments, the device with gas-liquid separation function can also be integrated into the first distributor 140 to improve the structural compactness of the evaporator 100.
[0046] Optionally, the voltage drop of the first distributor 140 is 5 kPa-20 kPa. For example, it can be 5 kPa, 10 kPa, 15 kPa, 20 kPa, etc., which can be set according to actual needs. This application does not make a specific limitation.
[0047] Optionally, the voltage drop of the second distributor 150 is 5 kPa-20 kPa. For example, it can be 5 kPa, 10 kPa, 15 kPa, 20 kPa, etc., which can be set according to actual needs. This application does not make a specific limitation. In order to improve the distribution effect, the voltage drop of the second distributor 150 should be less than or equal to the voltage drop of the first distributor 140.
[0048] Optionally, the first distributor 140 includes at least one first distribution plate and a plurality of first through holes disposed on the first distribution plate, through which liquid refrigerant is distributed. This first distributor 140 has a simple structure, is easy to control, and has low cost.
[0049] For example, the number of first distribution boards can be one, two, three, etc., depending on actual needs, and this application does not impose a specific limitation. When multiple first distribution boards are set, the multiple first distribution boards are stacked.
[0050] Preferably, the diameter of the first through hole is 6mm-12mm. For example, it can be 6mm, 7mm, 8mm, 9mm, 10mm, 11mm or 12mm, etc., which can be set according to actual needs. This application does not make specific limitations.
[0051] Optionally, the second distributor 150 includes at least one second distribution plate and a plurality of second through holes disposed on the second distribution plate, through which gaseous refrigerant is distributed. This second distributor 150 has a simple structure, is easy to control, and has a low cost.
[0052] For example, the number of second distribution boards can be one, two, three, etc., depending on actual needs, and this application does not impose a specific limitation. When multiple second distribution boards are set, the multiple second distribution boards are stacked.
[0053] Optionally, see [link to relevant documentation] Figure 1 The inlet of the gas-liquid separator 120 is connected to the first pipeline 160, which is equipped with a first electronic expansion valve 170. A liquid level detection element (not shown in the figure) is located inside the housing 110 to detect the liquid level within the housing 160. By controlling the opening of the first electronic expansion valve 170, the flow rate of the gas-liquid mixed refrigerant in the first pipeline 160 can be controlled. Combined with the liquid level detection element, this allows for control of the liquid level at the bottom of the housing 160 to meet operational requirements.
[0054] Of course, the first electronic expansion valve 170 can also be controlled according to other parameters, such as the superheat at the evaporator exhaust port 112. Alternatively, in a refrigeration system including the evaporator, it can be controlled according to parameters such as the condenser liquid level and the condenser subcooling.
[0055] It is understandable that the liquid level detection device can be, but is not limited to, a liquid level sensor.
[0056] Further, see also Figure 1 The liquid outlet 121 and the liquid inlet 111 are connected by a second pipeline 180, and a second electronic expansion valve 190 is provided on the second pipeline 180. The gas outlet 122 and the gas inlet 113 are directly connected by a third pipeline 1000.
[0057] With this configuration, when the second electronic expansion valve 190 is 100% open, the gas-liquid separator 120 operates close to an ideal state, meaning all liquid refrigerant enters the first distributor 140 through the second pipe 180, and all gaseous refrigerant enters the liquid accumulation area at the bottom of the housing 110 through the third pipe 1000. However, in this case, there is a large amount of liquid refrigerant in the first distributor 140, which can easily lead to some liquid refrigerant being discharged directly from the exhaust port without participating in heat exchange. This results in unevaporated refrigerant entering the compressor, causing liquid carryover during suction, and potentially damaging the compressor. Therefore, based on actual usage requirements, the opening of the second electronic expansion valve 190 can be reduced, allowing some liquid refrigerant to enter the first distributor 140, while the remaining liquid refrigerant mixes with the gaseous refrigerant and is transported to the liquid accumulation area at the bottom of the housing 110 through the third pipe 1000. This reduces liquid carryover during compressor suction and increases system reliability.
[0058] Understandably, the opening degree of the second electronic expansion valve 190 can be designed based on the performance of the first distributor 140 and the operating conditions of the evaporator.
[0059] Further, see also Figure 1 The interior of the shell 110 is divided into a falling film heat exchange zone 101 and a full liquid heat exchange zone 102. The falling film heat exchange zone 101 is located in the upper part of the shell 110, and the full liquid heat exchange zone 102 is located in the lower part of the shell 110. Multiple heat exchange tubes 130 are divided into falling film heat exchange tube bundles and full liquid heat exchange tube bundles. The falling film heat exchange tube bundles are arranged in the falling film heat exchange zone 101 and located below the first distributor 140, while the full liquid heat exchange tube bundles are arranged in the full liquid heat exchange zone 102.
[0060] This configuration allows the falling film heat exchange tube bundle to perform rapid and reliable heat exchange within the falling film heat exchange zone 101, and the flooded liquid heat exchange tube bundle to perform rapid and reliable heat exchange within the flooded liquid heat exchange zone 102. Compared to traditional falling film evaporators, this configuration ensures the heat exchange efficiency of the falling film evaporator tube bundle. Furthermore, it requires less refrigerant than traditional flooded liquid evaporators.
[0061] Further, see also Figure 1 The first distributor 140 has baffle plates 141 on opposite sides, which are inclined outwards, forming a trapezoidal structure. The falling film heat exchange tube bundle is located between the two baffle plates 141. The refrigerant that evaporates after heat exchange with the heat exchange tubes 130 rises to contact the baffle plates 141. A portion of the gaseous refrigerant condenses upon contact with the baffle plates 141 and flows down along them, dripping into the liquid-filled heat exchange zone 102 to participate in heat exchange. The remaining portion is discharged through the exhaust port 112. Therefore, by setting the baffle plates 141, the refrigerant utilization rate is improved, which to some extent helps reduce the refrigerant charge.
[0062] Optionally, a gas-liquid filter can be installed at the exhaust port 112. By installing a gas-liquid filter, the liquid ratio at the exhaust port 112 can be controlled, reducing liquid carryover during compressor intake and improving compressor reliability.
[0063] like Figure 3 As shown, this embodiment also provides a refrigeration system, including a compressor 200, a condenser 300, a throttle valve 400 and the aforementioned evaporator 100.
[0064] The compressor 200 outlet is connected to the condenser 300 inlet, the condenser 300 outlet is connected to the throttle valve 400 inlet, the throttle valve 400 outlet is connected to the gas-liquid separator 120 inlet, and the housing 110 exhaust port 112 is connected to the compressor 200 inlet.
[0065] It is worth noting that in the scheme where the inlet of the gas-liquid separator 120 is connected to the first pipeline 160 and a first electronic expansion valve 170 is installed on the first pipeline 160, the refrigeration system can be without a throttle valve 400. That is, in this case, the first electronic expansion valve 170 is equivalent to the throttle valve 400. Therefore, eliminating the throttle valve 400 simplifies the system structure while ensuring that the function of the refrigeration system remains unchanged.
[0066] Because this refrigeration system uses the aforementioned evaporator 100, the refrigerant charge is relatively small, reducing refrigerant costs and increasing refrigeration efficiency.
[0067] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.
Claims
1. An evaporator, characterized by include: The housing (110) has a liquid inlet (111) and an exhaust port (112) at its top and a gas inlet (113) at its bottom. A gas-liquid separator (120) is provided, through which a two-phase refrigerant enters the gas-liquid separator (120) via its inlet. The liquid outlet (121) of the gas-liquid separator (120) is connected to the liquid inlet (111) to deliver the liquid refrigerant into the housing (110). The gas outlet (122) of the gas-liquid separator (120) is connected to the gas inlet (113) to deliver the gaseous refrigerant into the housing (110). Multiple heat exchange tubes (130) are spaced apart inside the housing (110); A first distributor (140) is disposed within the housing (110) and above the plurality of heat exchange tubes (130), the first distributor (140) being configured to distribute liquid refrigerant onto the plurality of heat exchange tubes (130).
2. The evaporator of claim 1, wherein, Inside the housing (110), a second distributor (150) is provided below the plurality of heat exchange tubes (130), the second distributor (150) being used to distribute gaseous refrigerant.
3. The evaporator of claim 1, wherein, The inlet of the gas-liquid separator (120) is connected to the first pipeline (160), and the first pipeline (160) is provided with a first electronic expansion valve (170). The housing (110) is provided with a liquid level detection element.
4. The evaporator of claim 3, wherein, The liquid outlet (121) and the liquid inlet (111) are connected by a second pipeline (180), and a second electronic expansion valve (190) is provided on the second pipeline (180). The gas outlet (122) and the gas inlet (113) are directly connected by a third pipeline (1000).
5. The evaporator of claim 1, wherein, The interior of the shell (110) is divided into a falling film heat exchange zone (101) and a full liquid heat exchange zone (102). The falling film heat exchange zone (101) is located in the upper part of the shell (110), and the full liquid heat exchange zone (102) is located in the lower part of the shell (110). The multiple heat exchange tubes (130) are divided into falling film heat exchange tube bundles and full liquid heat exchange tube bundles. The falling film heat exchange tube bundles are arranged in the falling film heat exchange zone (101) and located below the first distributor (140). The full liquid heat exchange tube bundles are arranged in the full liquid heat exchange zone (102).
6. The evaporator of claim 5, wherein, The first distributor (140) has baffles (141) on its opposite sides, the baffles (141) are inclined outwards, and the falling film heat exchange tube bundle is located between the two baffles (141).
7. The evaporator according to any one of claims 1-6, characterized in that, The first distributor (140) includes at least one first distribution plate, which has a plurality of first through holes.
8. The evaporator of claim 2, wherein, The second distributor (150) includes at least one second distribution plate, which has a plurality of second through holes.
9. The evaporator of any one of claims 1-6, wherein, A gas-liquid filter screen is provided at the exhaust port (112).
10. A refrigeration system characterized by, The device includes a compressor (200), a condenser (300), a throttle valve (400), and an evaporator (100) according to any one of claims 1-9. The outlet of the compressor (200) is connected to the inlet of the condenser (300), the outlet of the condenser (300) is connected to the inlet of the throttle valve (400), the outlet of the throttle valve (400) is connected to the inlet of the gas-liquid separator (120), and the exhaust port (112) of the housing (110) is connected to the inlet of the compressor (200).