LU500695B1

LU500695B1 - Refrigeration system based on horizontal tube falling film-flooded evaporation

Info

Publication number: LU500695B1
Application number: LU500695A
Authority: LU
Inventors: Bing Hu
Original assignee: Univ Dongguan Technology
Priority date: 2021-09-28
Filing date: 2021-09-28
Publication date: 2022-04-11

Abstract

The present disclosure relates to the technical field of refrigeration systems, and more specifically relates to a refrigeration system based on horizontal tube falling film-flooded evaporation, including a refrigeration circulating system and a water path circulating system. The water path circulating system is connected with the refrigeration circulating system; the refrigeration circulating system includes a steam-liquid separator, a compressor, an oil separator, a condenser, a dry filter, a throttling valve, and an evaporator which are in closed-loop connection in sequence; a switching valve is arranged between the throttling valve and the evaporator; a falling film evaporation inlet and a flooded evaporation inlet which are respectively connected with different outlet ends of the switching valve are formed in the evaporator; and a refrigerant outlet end of the evaporator is connected with the steam-liquid separator.

Description

DESCRIPTION 500695

REFRIGERATION SYSTEM BASED ON HORIZONTAL TUBE FALLING FILM-FLOODED EVAPORATION TECHNICAL FIELD

[01] The present disclosure relates to the technical field of refrigeration systems, and more specifically relates to a refrigeration system based on horizontal tube falling film-flooded evaporation.

BACKGROUND

[02] Both a horizontal tube falling film evaporator and a flooded evaporator can be used as refrigeration evaporators. The horizontal tube falling film evaporator has a high heat transfer coefficient. Even when a heat transfer temperature difference is relatively small, a heat transfer process can be carried out successfully. Compared with the flooded evaporator, the falling film evaporator can save 30% of the amount of a refrigerant, which can not only reduce the initial input and maintenance cost of the refrigerant, but also reduce the probability of refrigerant leakage, so that the selection range of a substitutive refrigerant is expanded. The pressure of refrigerant fluid outside a tube of the horizontal tube falling film evaporator drops, and there is no static head generated by a liquid level, so that the temperature difference loss of the refrigerant outside the tube is small and the boiling point is stable, which is convenient for parameter control and experimental operation. In addition, the horizontal tube falling film evaporator also has good oil return performance. However, the application of the horizontal tube falling film evaporator used for refrigeration is restricted due to its complicated heat transfer mechanism, difficulty in refrigerant distribution, easy occurrence of "dry spots on evaporation tube", and other defects.

[03] The flooded evaporator has a high surface heat transfer coefficient because a surface of an evaporation tube is wetted by liquid. Water flows through the tube side, and the shell side is a liquid refrigerant in a phase change state. A heat exchange form is liquid and liquid heat exchange. The heat transfer temperature difference is small, but the refrigerant filling volume of the flooded evaporator is large, and the flooded 500695 evaporator has oil return difficulty.

[04] By integrating the advantages and disadvantages of the horizontal tube falling film evaporator and the flooded evaporator, a refrigeration system that can be switched between falling film evaporation and flooded evaporation is designed to be suitable for different application environments.

[05] For example, the Chinese patent No. CN209838606U discloses a multi-effect generator and an absorption type power-pumped jet refrigeration and power generation circulating system, including a shell, an inlet, a reflux inlet, a dilute solution outlet, a warm water pipe and a liquid distributor. The inlet, the reflux inlet, and the dilute solution outlet are all formed in the shell. The inlet includes a falling film evaporation inlet, a rising film evaporation inlet, and a flooded evaporation inlet. The falling film evaporation inlet, the rising film evaporation inlet, the reflux inlet, and the gas outlet are formed in a top surface of the shell. The flooded evaporation inlet and the dilute solution outlet are formed in a bottom surface of the shell. The warm water pipe and the liquid distributor are arranged in the shell. A plurality of layers of liquid distributors are arranged in the shell at intervals from top to bottom. The warm water pipe is arranged above each layer of liquid distributor, and at least one layer of warm water pipe is arranged below the last layer of liquid distributor. In this patent, ocean thermal energy which is widely spread low-grade heat energy is used to drive an absorption type working medium to conduct cold-electricity combined supply cycle, and solar energy is not needed. Waste heat and afterheat can independently realize the multi-level utilization of energy.

SUMMARY

[06] The present disclosure provides a refrigeration system based on horizontal tube falling film-flooded evaporation, which can realize switching between falling film evaporation and flooded evaporation and can be applicable to various different application environments, in order to solve the technical problem that the existing refrigeration system in the existing art adopts a single evaporator and cannot be suitable for different application environments. 7500695

[07] In order to solve the above-mentioned technical problem, the technical solution adopted by the present disclosure is a refrigeration system based on horizontal tube falling film-flooded evaporation, including a refrigeration circulating system and a water path circulating system; the water path circulating system is connected with the refrigeration circulating system; the refrigeration circulating system includes a steam-liquid separator, a compressor, an oil separator, a condenser, a dry filter, a throttling valve, and an evaporator which are in closed-loop connection in sequence; a switching valve is arranged between the throttling valve and the evaporator; a falling film evaporation inlet and a flooded evaporation inlet which are respectively connected with different outlet ends of the switching valve are formed in the evaporator; and a refrigerant outlet end of the evaporator is connected with the steam-liquid separator.

[08] In the present disclosure, low-pressure refrigerant steam becomes high-pressure superheated steam after being compressed by the compressor, then passes through the oil separator, and enters the condenser; after heat release in the condenser, the steam passes through the dry filter and then enters the throttling valve for throttling pressure reduction; a two-phase working medium that is throttled enters the evaporator for heat absorption and evaporation and then enters the steam-liquid separator for separation; and finally, the low-pressure refrigerant steam returns to the compressor, forming a complete cycle. The evaporator is provided with the falling film evaporation inlet and the flooded evaporation inlet which are respectively connected with the different outlet ends of the switching valve. By the arrangement of the switching valve, switching between the falling film evaporation and the flooded evaporation of the evaporator can be realized, so as to be applicable to various different application environments.

[09] Preferably, the evaporator includes an outer sleeve, a heat exchange pipe, and a liquid distributor; the heat exchange pipe and the liquid distributor are arranged in the outer sleeve; and the bottom of the outer sleeve is connected with a recirculating structure used for conveying unevaporated refrigerant liquid to the evaporator for continuous evaporation.

[10] Preferably, the liquid distributor includes a sprinkling pipe arranged in the outer sleeve and a height adjustment valve used for adjusting the height of the sprinkling pipe; 500695 the height adjustment valve is arranged on the outer sleeve; several sprinkling holes are uniformly formed in the sprinkling pipe at intervals; and the falling film evaporation inlet is arranged on the sprinkling pipe.

[11] Preferably, an aperture of the sprinkling hole is 1.5 to 2.5 mm, and a distance between adjacent sprinkling holes is 15 to 25 mm.

[12] Preferably, the recirculating structure includes a circulating pipe with one end connected to the bottom of the outer sleeve, and the other end of the circulating pipe communicates with the sprinkling pipe; and the circulating pipe is sequentially provided with a stop valve, a first flow meter, and a pump body.

[13] Preferably, a liquid return opening is formed in the middle position of the sprinkling pipe, and the circulating pipe is connected with the liquid return opening.

[14] Preferably, two falling film evaporation inlets are provided, which are located on two sides of the liquid return opening and have equal distances from the liquid return opening.

[15] Preferably, the height adjustment valve is located between the liquid return opening and the falling film evaporation inlet.

[16] The water path circulating system includes a chilling water system connected with the evaporator and a cooling water system used for cooling the high-temperature high-pressure refrigerant steam, and the cooling water system is connected with the condenser.

[17] Preferably, the chilling water system includes a water tank, a water pump, a flow meter, and a flow adjustment valve which communicate with each other in sequence; a water outlet of the water tank communicates with a water inlet end of the heat exchange pipe; and a water outlet end of the heat exchange pipe communicates with a water inlet of the water tank.

[18] Compared with the existing art, the present disclosure has the beneficial effects:

[19] 1) The whole refrigeration system of the present disclosure is reasonably set, and the evaporator can be applied to falling film evaporation or flooded evaporation, so as to be applicable to different application environments.

[20] 2) Compared with the single falling film evaporator or flooded evaporator, the 500695 present disclosure can select the falling film evaporation or flooded evaporation according to an actual need, so that the heat exchange efficiency can be improved, resources can be saved, and the energy consumption can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[21] FIG. 1 is a schematic structural diagram of a refrigeration system of the present disclosure;

[22] FIG. 2 is a schematic structural diagram of a liquid distributor of the present disclosure;

[23] FIG. 3 is a schematic structural diagram of a sprinkling pipe of the present disclosure;

[24] FIG. 4 is a schematic structural diagram of an evaporator of the present disclosure; and

[25] FIG. 5 is a schematic structural diagram of a chilling water system of the present disclosure.

[26] In the drawings: 10: steam-liquid separator; 11: compressor; 12: oil separator; 13: condenser; 14: dry filter; 15: throttling valve; 16: electromagnetic valve; 17: second flow meter; 2: evaporator; 21: outer sleeve; 22: heat exchange pipe; 221: water inlet end; 222: water outlet end; 23: falling film evaporation inlet; 24: flooded evaporation inlet; 25: refrigerant outlet end; 26: view window; 27: liquid discharging opening; 3: switching valve; 4: liquid distributor; 41: sprinkling pipe; 42: height adjustment valve; 43: sprinkling hole; 44: liquid return opening; 8: recirculating structure; 82: stop valve; 83: first flow meter; 84: pump body; 9: chilling water system; 91: water tank; 911: water outlet; 912: water inlet; 92: water pump; 93: third flow meter; 94: flow adjustment valve; 95: water supplementing pipeline.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[27] The accompanying drawings are only for illustrative purposes and cannot be understood as a limitation of this patent. In order to better illustrate the present embodiment, some parts of the accompanying drawings may be omitted, enlarged or 500695 reduced, and do not represent the size of the actual product. It is understandable for those skilled in the art that some known structures in the drawings and their descriptions may be omitted. The positional relationships described in the drawings are only for illustrative purpose and cannot be understood as a limitation to this patent.

[28] The same or similar reference signs in the drawings of the embodiments of the present disclosure correspond to the same or similar components. In the description of the present disclosure, it should be understood that if orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "long", "short", etc. are based on the orientations or positional relationships shown in the drawings, which are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying the device or element indicated must have the specific orientations and be constructed and operated in the specific orientations. Therefore, the wordings for describing the positional relationships in the drawings are for exemplary description only, and cannot be understood as a limitation to this patent. Those of ordinary skill in the art can understand the specific meanings of the above terms according to specific situations.

[29] The technical solutions of the present disclosure are further specifically described below by specific embodiments in conjunction with the accompanying drawings.

[30] Embodiment

[31] As shown in FIGS. 1-5, an embodiment of a refrigeration system based on horizontal tube falling film-flooded evaporation is illustrated, including a refrigeration circulating system and a water path circulating system. The refrigeration circulating system includes a steam-liquid separator 10, a compressor 11, an oil separator 12, a condenser 13, a dry filter 14, a throttling valve 15, and an evaporator 2. The compressor 11, the oil separator 12, the condenser 13, the dry filter 14, the throttling valve 15, and the evaporator 2 are in closed-loop connection through pipelines.

[32] Low-pressure refrigerant steam becomes high-pressure superheated steam after being compressed by the compressor 11, then passes through the oil separator 12, and enters the condenser 13. After heat release in the condenser 13, the steam passes through 500695 the dry filter 14 and then enters the throttling valve 15 for throttling pressure reduction. A two-phase working medium that is throttled enters the evaporator 2 for heat absorption and evaporation and then enters the steam-liquid separator 10 for separation. Finally, the low-pressure refrigerant steam returns to the compressor 11, forming a complete cycle.

[33] An electromagnetic valve 16 is further arranged between the condenser 13 and the dry filter 14. A second flow meter 17 is arranged between the dry filter 14 and the throttling valve 15. A switching valve 3 is arranged between the throttling valve 15 and the evaporator 2. The evaporator 2 is provided with a falling film evaporation inlet 23 and a flooded evaporation inlet 24. The falling film evaporation inlet 23 and the flooded evaporation inlet 24 are respectively connected with different outlet ends of the switching valve 3. The outlet end A of the switching valve 3 is connected with the falling film evaporation inlet 23, and the outlet end B of the switching valve 3 is connected with the flooded evaporation inlet 24. By the arrangement of the switching valve 3, switching between the falling film evaporation and the flooded evaporation of the evaporator 2 can be realized, so as to be applicable to different application environments.

[34] Specifically, the evaporator 2 includes an outer sleeve 21, a heat exchange pipe 22, a liquid distributor 4, and a recirculating structure 8. The outer sleeve 21 adopts a stainless steel pipe of ®57x2 mm, having a length of 3000 mm. The outer sleeve 21 is provided with two equally-spaced view windows 26. A view part is quartz glass and is connected to the pipe wall of the outer sleeve 21 through a flange. In order to facilitate observing the heat exchange inside the evaporator 2 from this view windows 26 more clearly and intuitively, a light source for illumination is further arranged in the outer sleeve 21. The heat exchange pipe 22 is a heat exchange pipe bundle mounted inside the outer sleeve 21. The heat exchange pipe 22 adopts an enhanced pipe.

[35] The flooded evaporation inlet 24 is arranged at the bottom of the outer sleeve 21. The top of the outer sleeve 21 is provided with a refrigerant outlet end 25. The refrigerant outlet end 25 is connected to the steam-liquid separator 10.

[36] The liquid distributor 4 is arranged at the inner top of the outer sleeve 21. 500695 Specifically, he liquid distributor 4 includes a sprinkling pipe 41 and a height adjustment valve 42. The sprinkling pipe 41 adopts a red copper pipe of ®20x2.5 mm, having a length of 1800 mm. Several sprinkling holes 43 are uniformly formed in the sprinkling pipe 41 at intervals. An aperture of each sprinkling hole 43 is 1.5 to 2.5 mm, and a distance between adjacent sprinkling holes 43 is 15 to 25 mm. In the present embodiment, the aperture of the sprinkling hole 43 is 2 mm, and the distance between the adjacent sprinkling holes 43 is 20 mm.

[37] A liquid return opening 44 is formed in the middle position of the sprinkling pipe 43. The recirculating structure 8 is connected with the liquid return opening 44. Specifically, the recirculating structure 8 includes a circulating pipe, a stop valve 82, a first flow meter 83, and a pump body 84. One end of the circulating pipe communicates with a liquid discharging opening 27 in the bottom of the outer sleeve 21, and the other end of the circulating pipe communicates with the liquid return opening 44. The stop valve 82, the first flow meter 83, and the pump body 84 are sequentially arranged on the circulating pipe. The pump body 84 adopts a working medium pump. During falling film evaporation, under the action of the pump body 84, unevaporated refrigerant liquid at the bottom of the outer sleeve 21 can enter the evaporator 2 again through the circulating pipe for continuous evaporation.

[38] The falling film evaporation inlet 23 is formed in the sprinkling pipe 41. In the present embodiment, two falling film evaporation inlets 23 are provided, which are located on both sides of the liquid return opening 44 and have equal distances from the liquid return opening 44, respectively.

[39] The height adjustment valve 42 is used for adjusting the height of the sprinkling pipe 41. The height adjustment valve 42 is arranged on the outer sleeve 21. Specifically, the height adjustment valve 42 is located between the liquid return opening 44 and the falling film evaporation inlet 23. In the present embodiment, two height adjustment valves 42 are provided. Each height adjustment valve 42 is located at a position that is 1/5 of the length of the outer sleeve 21 between the liquid return opening 44 and the falling film evaporation inlet 23 and is close to the falling film evaporation inlet 23.

[40] The water path circulating system includes a chilling water system and a 500695 cooling water system. The chilling water system is connected with the evaporator 2. Specifically, the chilling water system 9 includes a water tank 91, a water pump 92, a third flow meter 93, and a flow adjustment valve 94. The water tank 91, the water pump 92, the third flow meter 93, and the flow adjustment valve 94 are connected in sequence. The water pump 92 is arranged at a water outlet 911 of the water tank 91. The water outlet 911 of the water tank 91 is connected with a water inlet end 221 of the heat exchange pipe 22 in the evaporator 2 through a pipeline. A water outlet end 222 of the heat exchange pipe 22 communicates with a water inlet 912 of the water tank 91 through a pipeline. Under the driving of the water pump 92, chilling water enters the heat exchange pipe 22 of the evaporator 2 from the water outlet 911 of the water tank 91. A gas-liquid two-phase refrigerant is heated into saturated or superheated steam. The chilling water flows through the heat exchange pipe 22 and flows back into the water tank 91 from the water outlet end 222 of the heat exchange pipe 22. In addition, the chilling water system is further provided with an electric heater and some valve assemblies, which may be specifically set according to an actual need.

[41] The chilling water system is used for cooling the high-temperature high-pressure refrigerant steam. The cooling water system is connected with the condenser 13. The specific setting of the cooling water system is the same as the setting of the chilling water system. The water tank 91 in the cooling water system communicates with the condenser 13. In order to facilitate adjusting the temperatures in the chilling and cooling water tanks, each water tank 91 is connected with a water supplementing pipeline 95 for conveying tap water. A connection pipeline is further arranged between two water tanks 91 to realize temperature exchange.

[42] In order to prevent an extremely high temperature in the cooling water tank, the cooling water system is connected with an external cold source system. The external cold source system includes an outdoor unit, a plate type heat exchanger, a thermal expansion valve, and other structures. By means of cooperation with the electric heater and the outdoor cold source, continuous adjustment of the temperature in the water tank within a temperature range of 0 to 90 °C can be realized.

[43] In addition, a glass tube with scales is arranged in the water tank. The glass tube 500695 communicates with the water tank. A liquid level in the water tank can be observed through the glass tube. The bottom of the water tank is provided with a water drainage pipeline, and the side wall is connected with a water overflow pipeline. The water drainage pipeline can realize adjustment of the liquid level in the water tank. The maximum value of the liquid level is at an inlet of the water overflow pipeline, and the minimum value is at an inlet of the water pump.

[44] Obviously, the above-mentioned embodiments of the present disclosure are only for the purpose of clearly explaining the illustration made by the present disclosure, and are not intended to limit the implementation modes of the present disclosure. Those of ordinary skill in the art can further make other changes or modifications in different forms on the basis of the above-mentioned descriptions. It is unnecessary and may not enumerate all implementation modes here. Any modifications, equivalent replacements, improvements and the like that are made without departing from the spirit and the principle of the present disclosure shall fall within the scope of protection of claims of the present disclosure.

Claims

Claims LU500695

1. À refrigeration system based on horizontal tube falling film-flooded evaporation, comprising a refrigeration circulating system and a water path circulating system, the water path circulating system being connected with the refrigeration circulating system, characterized in that the refrigeration circulating system comprises a steam-liquid separator (10), a compressor (11), an oil separator (12), a condenser (13), a dry filter (14), a throttling valve (15), and an evaporator (2) which are in closed-loop connection in sequence; a switching valve (3) is arranged between the throttling valve (15) and the evaporator (2); a falling film evaporation inlet (23) and a flooded evaporation inlet (24) which are respectively connected with different outlet ends of the switching valve (3) are formed in the evaporator (2); and a refrigerant outlet end (25) of the evaporator (2) is connected with the steam-liquid separator (10).

2. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 1, wherein the evaporator (2) comprises an outer sleeve (21), a heat exchange pipe (22), and a liquid distributor (4); the heat exchange pipe (22) and the liquid distributor (4) are arranged in the outer sleeve (21); and the bottom of the outer sleeve (21) is connected with a recirculating structure (8) used for conveying unevaporated refrigerant liquid to the evaporator (2) for continuous evaporation.

3. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 2, wherein the liquid distributor (4) comprises a sprinkling pipe (41) arranged in the outer sleeve (21) and a height adjustment valve (42) used for adjusting the height of the sprinkling pipe (41); the height adjustment valve (42) is arranged on the outer sleeve (21); several sprinkling holes (43) are uniformly formed in the sprinkling pipe (41) at intervals; and the falling film evaporation inlet (23) is arranged on the sprinkling pipe (41).

4. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 3, wherein an aperture of the sprinkling hole (43) is 1.5 to 2.5 mm, and a distance between adjacent sprinkling holes (43) is 15 to 25 mm.

5. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 3, wherein the recirculating structure (8) comprises a circulating pipe with one end connected to the bottom of the outer sleeve (21), and the 500695 other end of the circulating pipe communicates with the sprinkling pipe (41); and the circulating pipe (81) is sequentially provided with a stop valve (82), a first flow meter (83), and a pump body (84).

6. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 5, wherein a liquid return opening (44) is formed in the middle position of the sprinkling pipe (41), and the circulating pipe (81) is connected with the liquid return opening (44).

7. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 6, wherein two falling film evaporation inlets (23) are provided; the two falling film evaporation inlets (23) are located on two sides of the liquid return opening (44) and have equal distances from the liquid return opening (44).

8. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 3, wherein the height adjustment valve (42) is located between the liquid return opening (44) and the falling film evaporation inlet (23).

9. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 2, wherein the water path circulating system comprises a chilling water system (9) connected with the evaporator (2) and a cooling water system used for cooling high-temperature high-pressure refrigerant steam, and the cooling water system is connected with the condenser (13).

10. The refrigeration system based on horizontal tube falling film-flooded evaporation according to claim 9, wherein the chilling water system (9) comprises a water tank (91), a water pump (92), a flow meter (93), and a flow adjustment valve (94) which communicate with each other in sequence; a water outlet (911) of the water tank (91) communicates with a water inlet end (221) of the heat exchange pipe (2); and a water outlet end (222) of the heat exchange pipe (22) communicates with a water inlet (912) of the water tank (91).