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Title:
CONDENSATION AND FALLING FILM EVAPORATION HYBRID HEAT EXCHANGER
Document Type and Number:
WIPO Patent Application WO/2017/160369
Kind Code:
A1
Abstract:
A condensation and falling film evaporation hybrid heat exchanger is provided, including a shell, a condenser entrance pipe connected to a compressor discharge port, and an evaporator exit pipe connected to a compressor suction port being disposed respectively on the shell. A baffle plate is disposed at a position inside the shell corresponding to the condenser entrance pipe. A refrigerant distributor is disposed in the shell, a condensing tube bundle being disposed above the refrigerant distributor, and a falling film evaporating tube bundle being disposed below the refrigerant distributor. The condensation and falling film evaporation hybrid heat exchanger according to this invention can be used in concert with low-pressure refrigerant, thus efficiently solving the problem of refrigerant distribution with the falling film evaporator using low-pressure refrigerant.

Inventors:
SU XIUPING (CN)
WANG LI (CN)
SCHREIBER JEB W (US)
GALLUS BRIAN THOMAS (US)
FORD SCOTT ALLEN (US)
Application Number:
US2016/068420
Publication Date:
September 21, 2017
Filing Date:
December 22, 2016
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
JOHNSON CONTROLS TECH CO (US)
YORK (WUXI) AIR CONDITIONING AND REFRIGERATION CO LTD (CN)
International Classes:
F25B39/02; F28D3/02; F28D3/04; F28D21/00
Domestic Patent References:
WO2013074749A12013-05-23
Foreign References:
US20130277018A12013-10-24
JPS61125588A1986-06-13
JP2007198700A2007-08-09
GB1206643A1970-09-23
JPS60228894A1985-11-14
Other References:
None
Attorney, Agent or Firm:
KANTOR, Andrew L. et al. (Houston, Texas, US)
Download PDF:
Claims:
CLAIMS

1. A condensation and falling film evaporation hybrid heat exchanger for a refrigeration and air-conditioning unit, including a shell, wherein a condenser entrance pipe connected to a compressor discharge port, and an evaporator exit pipe connected to a compressor suction port are disposed respectively on the shell, a refrigerant distributor is disposed in the shell, a condensing tube bundle being disposed above the refrigerant distributor, and a falling film evaporating tube bundle being disposed below the refrigerant distributor.

2. The condensation and falling film evaporation hybrid heat exchanger for a refrigeration and air-conditioning unit of Claim 1, further comprising a baffle plate being disposed at a position inside the shell corresponding to the condenser entrance pipe.

3. The condensation and falling film evaporation hybrid heat exchanger of Claim 1, wherein the refrigerant distributor is a perforated plate with multiple through-holes disposed thereon.

4. The condensation and falling film evaporation hybrid heat exchanger of Claim 3, wherein:

hollow short tubes along the direction of the condensing tube bundle extending out of the perforated plate are disposed on the perforated plate;

the hollow short tubes being configured to be equally spaced apart from each other.

5. The condensation and falling film evaporation hybrid heat exchanger of Claim 4, wherein:

the hollow short tubes have at least two different heights;

the hollow short tubes with a same height being configured to be equally spaced apart from each other.

6. The condensation and falling film evaporation hybrid heat exchanger of Claim 3, wherein floaters are disposed in the through-holes.

7. The condensation and falling film evaporation hybrid heat exchanger of Claim 6, wherein:

the through-hole IS configured as a taper hole with a downward conical tip; and

a lower portion of the floater is configured as a cone cooperating with the through-hole.

8. The condensation and falling film evaporation hybrid heat exchanger of Claim 6, wherein:

the floater comprises a floater rod and a floater body being disposed at the top end of the floater rod;

a cavity being disposed inside the floater rod; and

multiple groove-shaped through-holes connected to the cavity of the floater rod being disposed on the floater rod.

9. The condensation and falling film evaporation hybrid heat exchanger of Claim 7, wherein top portions of the multiple floaters are connected by a connector.

10. The condensation and falling film evaporation hybrid heat exchanger of Claim 8, wherein floater bodies of the floaters are connected by a connector.

11. The condensation and falling film evaporation hybrid heat exchanger of Claim 9, wherein the floaters are connected to a controller, the controller controlling the rising and falling of the floaters.

12. The condensation and falling film evaporation hybrid heat exchanger of Claim 10, wherein the floaters are connected to a controller, the controller controlling the rising and falling of the floaters.

13. The condensation and falling film evaporation hybrid heat exchanger of Claim 1, further comprising an additional perforated plate being disposed in the shell above the refrigerant distributor, and dividing the condensing tube bundle into upper and lower groups.

14. The condensation and falling film evaporation hybrid heat exchanger of Claim 1, wherein the cross-section of the shell vertical to the extension direction of the condensing tube bundle is a circle or a rectangle.

15. The condensation and falling film evaporation hybrid heat exchanger of Claim 1, wherein a bypass pipe disposed at one side of the shell is connected to a bottom of the condensing tube bundle and a bottom of the falling film evaporating tube bundle.

16. The condensation and falling film evaporation hybrid heat exchanger of Claim 15, wherein a regulating valve is disposed on the bypass pipe.

17. A condensation and falling film evaporation hybrid heat exchanger for a refrigeration and air-conditioning unit, including a shell, wherein a condenser entrance pipe connected to a compressor discharge port, and an evaporator exit pipe connected to a compressor suction port are disposed respectively on the shell, a refrigerant distributor is disposed in the shell, a condensing tube bundle being disposed above the refrigerant distributor, and a falling film evaporating tube bundle being disposed below the refrigerant distributor; wherein the refrigerant distributor comprises a perforated plate with multiple through-holes disposed thereon, and wherein a protrusion extends from a bottom surface of the perforated plate toward the falling film evaporating tube bundle at an outlet of one of the multiple through-holes.

18. The condensing and falling film evaporation hybrid heat exchanger of

Claim 17, wherein the multiple through-holes and the protrusion are formed by a stamping process.

Description:
CONDENSATION AND FALLING FILM EVAPORATION

HYBRID HEAT EXCHANGER

FIELD OF THE INVENTION

[0001] This invention is directed to the field of refrigerant and air-conditioning apparatus, in particular, a condensation and falling film evaporation hybrid heat exchanger.

BACKGROUND OF THE INVENTION

[0002] Typically, conventional refrigerant and air-conditioning units include four major components, namely, compressor, condenser, throttling device and evaporator.

[0003] A prior art condenser 10 generally adopts the structure as illustrated in FIG. 1, which has a refrigerant entrance 11, a refrigerant exit 15, a baffle plate 12 and a condensing tube bundle 13 being disposed or positioned inside the condenser 10, a subcooler 14 generally being further disposed or positioned at a bottom of the condenser 10.

[0004] A prior art falling film evaporator 20 with the characteristics such as higher heat transfer efficiency and lower refrigerant charge has been more and more frequently applied to the vapor compression systems in refrigeration, air conditioning and chilled liquid systems. The prior art falling film evaporator 20 generally adopts the structure as illustrated in FIG. 2, including an evaporator exit pipe 21, a feeding pipe 22, a refrigerant distributor 23 and an evaporating tube bundle 24. The refrigerant distributor 23 in FIG. 2 is a key component of the falling film evaporator 20, and in order to achieve uniform distribution of the refrigerant to the evaporating tube bundle 24, it is necessary that sufficient pressure difference exists between an interior and an exterior of the refrigerant distributor 23. In a system with middle and high-pressure refrigerant (e.g. R134a, etc.), the pressure difference between the interior and the exterior of the refrigerant distributor 23 generally reaches 150-300kPa. [0005] The low-pressure refrigerant R1233zd(E) has received increased aiienuon in me HVAC&R industry due to its advantages such as environmental friendliness and high efficiency, etc. Under a typical working condition (evaporation temperature SOC, condensation temperature 36.7°(), in a comparison between R1233zd(E) and R134a in terms of evaporation pressure and condensation pressure, the difference between the evaporation pressure and the condensation pressure of R1233zd(E) is only 23.1% of that of R134a. With respect to low-pressure refrigerants like R1233zd(E), the refrigerant distributor 23 in the conventional or prior art falling film evaporator 20 may not be able to satisfy operating load requirements.

[0006] Accordingly, there is a need for a condensation and falling film evaporation hybrid heat exchanger that can be used with low-pressure refrigerant, thus efficiently solving the problem of refrigerant distribution with the falling film evaporator using low-pressure refrigerant.

BRIEF DESCRIPTION OF THE INVENTION

[0007] In order to solve the aforesaid problems, this invention provides a condensation and falling film evaporation hybrid heat exchanger for a refrigerant and air- conditioning unit, including a shell, wherein a condenser entrance pipe connected to the compressor discharge port, and an evaporator exit pipe connected to the compressor suction port are disposed respectively on the shell. A refrigerant distributor is disposed in the shell, a condensing tube bundle being disposed above the refrigerant distributor, and a falling film evaporating tube bundle being disposed the refrigerant distributor.

[0008] In one embodiment, a baffle plate is included, the baffle plate being disposed at a position inside the shell corresponding to the condenser entrance tube.

[0009] In one embodiment, the refrigerant distributor is a perforated plate with multiple through-holes disposed thereon.

[0010] In one embodiment, hollow short tubes along the direction of the condensing tube bundle extending out of the perforated plate are disposed on the perforated plate, the hollow short tubes being configured to be equally spaced apart from each other. [0011] In one embodiment, the hollow short tubes have at least two airrereni heights, the hollow short tubes with the same height being configured to be equally spaced apart from each other.

[0012] In one embodiment, floaters are disposed in the through-holes.

[0013] In one embodiment, the through-hole is configured as a taper hole with a downward conical tip, and a lower portion of the floater is configured as a cone cooperating with the through-hole.

[0014] In one embodiment, the floater comprises a floater rod and a floater body disposed at the top end of the floater rod, a cavity being disposed inside the floater rod, multiple groove-shaped through-holes connected to the cavity of the floater rod being disposed on the floater rod.

[0015] In one embodiment, top portions of the multiple floaters are connected by a connector.

[0016] In one embodiment, floater bodies of the floaters are connected by a connector.

[0017] In one embodiment, the floaters are connected to a controller, the controller controlling the rising and falling of the floaters.

[0018] In one embodiment, an additional perforated plate is disposed in the shell above the refrigerant distributor, and divides multiple condensing tube bundles into upper and lower groups.

[0019] In one embodiment, the cross-section of the shell vertical to the extension direction of the condensing tube bundle is a circle or a rectangle.

[0020] In one embodiment, a bypass pipe is disposed at one side of the shell connected to a bottom of the condensing tube bundle and a bottom of the falling film evaporating tube bundle.

[0021] In one embodiment, a regulating valve is disposed on the bypass pipe. [0022] In one embodiment, the condensation and falling film evaporation nyona neai exchanger includes a shell, a condenser entrance pipe connected to the compressor discharge port, and an evaporator exit pipe connected to the compressor suction port being disposed respectively on the shell. A baffle plate is disposed at a position inside the shell corresponding to the condenser entrance tube. A refrigerant distributor is disposed in the shell, a condensing tube bundle being disposed above the refrigerant distributor, and a falling film evaporating tube bundle being disposed below the refrigerant distributor. The condensation and falling film evaporation hybrid heat exchanger can be used with low-pressure refrigerant, thus efficiently solving the problem of refrigerant distribution with the falling film evaporator using low-pressure refrigerant.

[0023] Other features and advantages of the present invention will be apparent from the following more detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following drawings of the embodiments in this invention constitute a part of this invention for understanding this invention. The drawings illustrate the embodiments of this invention and the descriptions thereof for explaining the principles of this invention. The drawings are provided as follows:

[0025] FIG. 1 is a section view of a prior art condenser.

[0026] FIG. 2 is a section view of a prior art falling film evaporator.

[0027] FIG. 3 is a section view of a condensation and falling film evaporation hybrid heat exchanger according to an embodiment of this invention.

[0028] FIG. 4 is a stereoscopic view of a refrigerant distributor according to the first embodiment of this invention.

[0029] FIG. 5 is a stereoscopic view of a refrigerant distributor according to the second embodiment of this invention. [0030] FIG. 6 is a section view of a refrigerant distributor according ιο ine inira embodiment of this invention.

[0031] FIG. 7 is a section view of a refrigerant distributor according to the fourth embodiment of this invention.

[0032] FIG. 8a is a stereoscopic view of a refrigerant distributor according to the fifth embodiment of this invention.

[0033] FIG. 8b is a stereoscopic view of a refrigerant distributor according to the fifth embodiment of this invention, wherein a single floater is illustrated.

[0034] FIG. 9 is a section view of a condensation and falling film evaporation hybrid heat exchanger according to another embodiment of this invention.

[0035] FIG. 10 is a refrigeration cycle diagram of a condensation and falling film evaporation hybrid heat exchanger with an additional perforated plate.

[0036] FIG. 1 1 is a section view of a condensation and falling film evaporation hybrid heat exchanger according to a further embodiment of this invention.

[0037] FIG. 12 is a section view of a condensation and falling file evaporation hybrid heat exchanger according to an additional embodiment of this invention.

[0038] FIG. 13 is a detailed cross-sectional view of an embodiment of a perforated plate that may be used as a refrigerant distributor within the falling film evaporation hybrid heat exchanger of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0039] In the following descriptions, many details are given for more thorough understanding of this invention. However, it is obvious for those skilled in the art that the embodiments of this invention can be implemented without one or more details of such. In other examples, to avoid confusion with the embodiments of this invention, some common technical features in the art are not described. [0040] For thorough understanding of the embodiments of this invention, me aeianea structures are brought forward in the following descriptions. Obviously, the implementation of the embodiments of this invention is not limited to such special details that those skilled in the art are familiar with. The more preferable embodiments of this invention are described in details as follows, while apart from such detailed descriptions, this invention may have other embodiments.

[0041] Referring to FIG. 3, the condensation and falling film evaporation hybrid heat exchanger 30 includes a shell37.

[0042] The cross-section of the shell 37 in the embodiment as illustrated is a circle, a condenser entrance pipe 31 and an evaporator exit pipe 33 being disposed on the shell 37. The condenser entrance pipe 31 is to be connected to the compressor discharge port (not illustrated). The evaporator exit pipe 33 is to be connected to the compressor suction port (not illustrated).

[0043] A baffle plate 32 is disposed at a position inside the shell corresponding to the condenser entrance tube 31 for slowing down and reducing the impact of refrigerant gas entering into the shell 37 from the condenser entrance tube 31 on the condensing tube bundle 34.

[0044] A refrigerant distributor 36 is disposed at a roughly central position of the shell 37, the refrigerant distributor 36 being disposed roughly horizontally as illustrated, above which the condensing tube bundle 34 (condensing tubes) are disposed and form the condenser (region). The falling film evaporating tube bundle 35 (evaporation tubes) is disposed below the refrigerant distributor 36 and form the evaporator (region).

[0045] The condensation and falling film evaporation hybrid heat exchanger 30 of this invention operates in such a way: while the system is operating, the refrigerant gas from the compressor discharge port (not illustrated) enters into the shell 37 of the condensation and falling film evaporation hybrid heat exchanger 30 via the condenser entrance pipe 31, and after passing the condensing tube bundle 34, is condensed as high-pressure liquid, with liquid droplets being equally or uniformly provided or distributed to the refrigerant distributor 36. The refrigerant distributor 36 may produce a pressure difference required by refrigeration cycle, and the high-pressure refrigerant liquid via the refrigerani aisiriouior J O may be changed into low-pressure two-phase fluid, with liquid droplets of the two-phase fluid being equally or uniformly provided or distributed to the falling film evaporating tube bundle 35 for evaporation, and then be changed into low-temperature low-pressure refrigerant vapor, and finally via the evaporator exit pipe 33 returns the compressor suction port (not illustrated).

[0046] Therefore, the condensation and falling film evaporation hybrid heat exchanger of this invention makes use of the characteristic of equal distribution of the refrigerant liquid dripped from the condensing tube bundle so that equal distribution of the refrigerant required by the falling film evaporator can be achieved requiring no complicated refrigerant distributor. The refrigerant distributor functions as a throttling device at the same time.

[0047] FIG. 4 illustrates the first embodiment of the refrigerant distributor 36 of this invention. Specifically, the refrigerant distributor 36 in the embodiment as illustrated is a perforated plate 361, multiple through-holes 362 being disposed on the perforated plate 361. For equal distribution, the through-holes 362 are equally disposed on the perforated plate 361. Those skilled in the art should know that pressure difference above and below the perforated plate 361 may satisfy the pressure difference required by refrigeration cycle.

[0048] Referring to FIG. 5, in the second embodiment of the refrigerant distributor 36 of this invention, hollow short tubes 363 extending upward and out of the perforated plate 361 are disposed at a portion of the through-holes 362. In other words, hollow short tubes 363 extend out with certain heights from the perforated plate 361 facing to the condensing tube bundle 34. An axially penetrating through- hole may be disposed inside the hollow short tubes 363 so that the short tubes 363 are connected to the through-holes 362, and equally spaced apart from each other on the perforated plate 361.

[0049] It can be understood that the hollow short tubes 363 may not be disposed at the through-holes 362 already on the perforated plate 361, but may be disposed penetrating the perforated plate 361 independent from the through-holes 362. [0050] Further, the hollow short tubes 363 may have different heights, ana me nonow short tubes with same height are equally spaced apart from each other. In FIG. 5, the hollow short tubes 363 with two heights are illustrated as an example, wherein the height of first hollow short tubes 3631 is HI, and the height of second hollow short tubes 3632 is H2. The height H2 of the second hollow short tubes 3632 is larger than the height HI of the first hollow short tubes 3631.

[0051] In this way, in the process of operation of the unit, the refrigerant flows from the condenser (the part above the refrigerant distributor 36) into the evaporator (the part below the refrigerant distributor 36) via the through-holes 362. If the flow via the through-holes 362 is insufficient, the liquid level in the condenser (the part above the refrigerant distributor 36) will rise.

[0052] When the liquid level exceeds the height HI of the first hollow short tubes 3631, a part of the refrigerant will run from the condenser (the part above the refrigerant distributor 36) into the evaporator (the part below the refrigerant distributor 36) via the through-holes inside the first hollow short tubes 3631, so as to increase the flow of the refrigerant. If the flow is still insufficient, the liquid level in the condenser (the part above the refrigerant distributor 36) will further rise.

[0053] When the liquid level exceeds the height H2 of the second hollow short tubes 3632, a part of the refrigerant will flow from the condenser (the part above the refrigerant distributor 36) into the evaporator (the part below the refrigerant distributor 36) via the through-holes inside the second hollow short tubes 3632 so as to further increase the flow of the refrigerant.

[0054] To the contrary, if the flow is too large, the liquid level in the condenser (the part above the refrigerant distributor 36) will fall. When the liquid level is lower than the height H2 of the second hollow short tubes 3632, the refrigerant will no longer run towards the evaporator via the second hollow short tubes 3632, so as to decrease the flow of the refrigerant. The principle and function of the first hollow short tubes 3631 are similar to the above. [0055] FIG. 6 illustrates the third embodiment of a refrigerant disinouior J O or inis invention. In this embodiment, a floater 364 is disposed in the through-tube 362. Specifically, the through-tube 362 may be configured as a taper hole with a downward conical tip, while the floater 364 may be configured as a cone cooperating with the through-hole 362.

[0056] The refrigerant distributor 36 is composed of the perforated plate 361 and the floater 364, and the floater may be made of the material with density less than the refrigerant liquid so that the floater stressed by the buoyant force from the refrigerant liquid may at least partially move upward from the through-hole 362 when it is in touch with the refrigerant liquid.

[0057] The through-hole 362 on the perforated plate 361 in the embodiment as illustrated in FIG. 6 is a taper hole. The floater 364 is provided with a segment of cone cooperating with the through-hole 362 in the form of taper hole. In operation, when the liquid level in the condenser rises, the refrigerant liquid is in touch with the cone part of the floater 364, and the buoyant force that the floater 364 receives is greater than the gravity force itself, and thus the floater 364 moves upward. In this way, the refrigerant liquid may run towards the evaporator via the hole space between the through-tube 362 on the perforated plate 361 and the cone of the floater 364.

[0058] When the liquid level in the condenser rises, the buoyant force that the floater 364 receives increases and the floater 364 goes up so that the hole space is enlarged and the flow of the refrigerant passing the refrigerant distributor 36 increases. Subsequently, regulation of the refrigerant flow is achieved.

[0059] When the liquid level in the condenser falls, the buoyant force that the floater 364 receives decreases and the floater 364 goes down so that the hole space is diminished and the flow of the refrigerant passing the refrigerant distributor 36 decreases. Subsequently, regulation of the refrigerant flow is achieved.

[0060] Referring to FIG. 7, in which the refrigerant flow is even and controllable, the top portions of the multiple floaters may be connected by a connector. [0061] Specifically, FIG. 7 illustrates the fourth embodiment of the rerngerani aisiriouior 36 of this invention. The refrigerant distributor 36 is composed of the perforated plate 361 and the floaters 364, and the multiple floaters 364 are connected together by a flat 365 (one example of the connector) so that the multiple floaters 364 connected together may go up or down simultaneously and consequently the hole space between the floaters 364 and the through-tubes 362 is enlarged or diminished synchronously.

[0062] Further, a controller (not illustrated) connected to the connector may also be disposed, i.e. upward and downward movement of the floaters 364 connected together may be controlled such as by a stepping motor (one example of the controller) so that control of the refrigerant flow is achieved.

[0063] Referring to FIG. 8a and FIG. 8b, the fifth embodiment of the refrigerant distributor 36 of this invention is illustrated. Alternatively, as illustrated in FIG. 8b, the floater 364 includes a floater rod 367 and a floater body 366 disposed on the top end of the floater rod 367. The floater body 366 may radially extend out of the floater 367. A cavity may be disposed inside the floater rod 367, and multiple through-holes connected to the cavity of the floater rod 367 are disposed on a peripheral surface of the floater rod 367. In this embodiment, the through-holes are groove-shaped through- holes 368, which extend radially on the peripheral surface of the floater rod 367 and are connected to the cavity of the floater rod 367 in the radial direction of the floater rod 367. Of course, the through- holes may be constituted in other shapes, such as circular through-holes or rectangular through-holes, etc. The refrigerant may, via the groove-shaped through-holes 368 on the floater rod 367, enter into the floater rod 367 and further flow towards the evaporator.

[0064] In operation, when the liquid level in the condenser rises up, the buoyant force that the floater rod 367 receives increases. The floater 364 moves upward so that the area of the groove-shaped through-holes 368 higher than the perforated plate 361 is enlarged. Subsequently, the flow of the refrigerant passing the groove-shaped through-holes 368 increases.

[0065] When the liquid level in the condenser falls down, the buoyant force that the floater rod 367 receives decreases. The floater 364 moves downward so that the area of the groove-shaped through-holes 368 higher than the perforated plate 361 is diminished. Subsequently, the flow of the refrigerant passing the groove-shaped mrougn-noies J OO decreases so that regulation of the refrigerant flow is achieved.

[0066] In addition, as illustrated in FIG. 8a, the floater bodies 366 of the multiple floaters 364 may also be connected together as an entirety by the connector as above, and the rising and falling of the floaters 364 connected together may be controlled by the controller such as a stepping motor as well so as to regulate the flow.

[0067] Now switching to FIG. 9, another embodiment of the condensation and falling film evaporation hybrid heat exchanger 30 of this invention is illustrated. Compared with the embodiment as illustrated in FIG. 3, a piece of additional perforated plate 38 is added in the condensing tube bundle 34. The additional perforated plate 38 is disposed above the refrigerant distributor 36 and divides the condensing tube bundle 34. The additional perforated plate 38 may be disposed roughly parallel to the condenser distributor 36, and function to throttle flow and reduce pressure, thereby increasing refrigerating output.

[0068] FIG. 10 illustrates a LogP-h diagram of a refrigeration cycle, wherein DP=Pc-Pl refers to a pressure drop produced by the additional perforated plate 38, and DH=hl'-hl refers to the added enthalpy after adopting the additional perforated plate 38. It can be seen from this figure that without the additional perforated plate 38, refrigeration cycle efficiency is: COPl=(h2-hl')/(h3-h2), while with the additional perforated plate 38, refrigeration cycle efficiency is: COP2=(h2-hl)/(h3-h2). After the additional perforated plate 38 is adopted, refrigeration cycle efficiency increases DH/(h3-h2).

[0069] In addition, as illustrated in FIG. 11, the cross-section shape of the shell 37 of the condensation and falling film evaporation hybrid heat exchanger 30 of this invention may be a circle or a rectangle. Since the low-pressure refrigerant is adopted and a side of the container shell 37 is not pressure-bearing, either a circular shell or a rectangular shell 37' as illustrated in FIG. 11 may be adopted, simplifying both pipe distribution and production.

[0070] As illustrated in FIG. 12, in another embodiment, a bypass pipe 39 is disposed between a bottom of the condenser (an upper part of the refrigerant distributor 36) and a bottom of the evaporator (a lower part of the refrigerant distributor 36), i.e. one side of the shell is provided with a bypass pipe connected to a Doiiom or ine condensing tube bundle and a bottom of the falling film evaporating tube bundle.

[0071] Further, a regulating valve 391 is disposed on the bypass pipe 39, and the refrigerant flow entering into the evaporator may be regulated by the regulating valve 391 on the bypass pipe 391. Under the circumstances, those skilled in the art should know that heat exchange tubes at the bottom of the evaporator are equivalent to full- liquid heat exchange, while at the top, it is still falling film heat exchange.

[0072] This invention has been explained by the aforesaid embodiments. However, it should be understood that the aforesaid embodiments are only for the purpose of giving examples and making explanations, rather than having this invention limited to the scope of the embodiments described. Furthermore, those skilled in the art are in a position to understand that this invention is not limited to the aforesaid embodiments, and according to the instructions of this invention, more modifications and revisions may be made, which all fall into the protection scope of this invention.

[0073] FIG. 13 is a detailed cross-sectional view of an embodiment of a perforated plate 400 that may be used as a refrigerant distributor within the falling film evaporation hybrid heat exchanger of FIG. 3. Similar to the perforated plate 361 described above with reference to FIG. 4, the perforated plate 400 includes multiple through-holes 402 that facilitate flow of refrigerant from the condenser region 404 to the evaporator region 406. In the illustrated embodiment, the perforated plate includes protrusions 408 extending from a bottom surface 410 of the perforated plate 400. As illustrated, each protrusion 408 is positioned at an outlet 412 of a respective through-hole 402. The protrusions 408 are configured to induce the refrigerant flowing through the through-holes 402 to form droplets, which then fall downwardly under the influence of gravity into the evaporator region 406.

[0074] A height 414 of each protrusion 402 may be particularly selected to establish a desired droplet size. In addition, a profile (e.g., shape) of each protrusion may be particularly configured to establish a desired droplet size. For example, in certain embodiments, the protrusion may extend about an entire periphery (e.g., circumference) of the through-hole outlet. However, in alternative embodiments, the protrusion may extend about a portion of the periphery (e.g., about 5 percent to about 95 percent, aooui ιυ percent to about 90 percent, about 20 percent to about 80 percent, about 30 percent to about 70 percent, or about 40 percent to about 60 percent, etc.), and/or multiple protrusions may be positioned at the outlet of at least one through-hole. In certain embodiments, at least one protrusion may be positioned at the outlet of each through-hole. However, in alternative embodiments, protrusion(s) may be positioned at a portion of the through-hole outlets. Furthermore, in certain embodiments, the heights and/or profiles of the protrusions may be substantially the same as one another, or at least a portion of the protrusions have different heights and/or profiles.

[0075] In certain embodiments, the through-holes and the protrusions may be formed by a stamping process. For example, during the stamping process, projections of a die may engage a solid plate, thereby displacing material of the solid plate to form the through- holes. The projections may be particularly configured such that the displaced material forms the protrusions on the bottom surface of the plate. For example, the shape and/or configuration of each projection may be particularly selected such that a respective protrusion having a desired height and/or profile is formed. In certain embodiments, the protrusions may be further shaped by post-stamping process(es), such as grinding and/or trimming, among others. In further embodiments, the protrusions may be formed separately and coupled to the bottom surface of the perforated plate (e.g., by welding, by adhesively bonding, etc.). It should be appreciated that the protrusions may be employed on any of the perforated plates described above with reference to FIGS. 4-9 and 11-12.

DESCRIPTION OF DRAWING SIGNS:

10. condenser

11. refrigerant entrance

12. baffle

13. condensing tube bundle

14. subcooler

15. refrigerant exit

20. falling film evaporator

21. evaporator exit pipe

22. feeding pipe

23. refrigerant distributor

24. evaporator tube bundle

30. condensation and falling film evaporation hybrid heat exchanger 31. condenser entrance pipe

32. baffle

33. evaporator exit pipe

34. condensing tube bundle

35. falling film evaporating tube bundle

36. refrigerant distributor

361. perforated plate

362. through-hole

363. hollow short tube

3631. first hollow short tube

3632. second hollow short tube

364. floater

365. flat

366. floater body

367. floater rod

368. groove -shaped through-hole

37. shell

37'. shell

38. additional perforated plate

39. by-pass pipe

391. regulating valve