U.S. patent application number 12/812756 was filed with the patent office on 2011-08-25 for heat exchanger including multiple tube distributor.
Invention is credited to Robert Hong-Leung Chiang, PingLi Hou.
Application Number | 20110203308 12/812756 |
Document ID | / |
Family ID | 39765247 |
Filed Date | 2011-08-25 |
United States Patent
Application |
20110203308 |
Kind Code |
A1 |
Chiang; Robert Hong-Leung ;
et al. |
August 25, 2011 |
HEAT EXCHANGER INCLUDING MULTIPLE TUBE DISTRIBUTOR
Abstract
A heat exchanger includes tubes and an inlet manifold to direct
a first fluid into the tubes at a third direction. Heat is
exchanged between the first fluid and a second fluid in the tubes.
The heat exchanger also includes a distributor tube located within
the inlet manifold. The distributor tube includes a short tube
including a plurality of first orifices that direct the first fluid
into the inlet manifold at a first direction, and a long tube
including a plurality of second orifices that direct the first
fluid into the inlet manifold at a second direction.
Inventors: |
Chiang; Robert Hong-Leung;
(Manlius, NY) ; Hou; PingLi; (Bengbu, CN) |
Family ID: |
39765247 |
Appl. No.: |
12/812756 |
Filed: |
March 20, 2008 |
PCT Filed: |
March 20, 2008 |
PCT NO: |
PCT/US08/57567 |
371 Date: |
April 19, 2011 |
Current U.S.
Class: |
62/498 ;
165/174 |
Current CPC
Class: |
F28F 9/0273 20130101;
F25B 39/028 20130101; F28F 1/022 20130101; F25B 39/022
20130101 |
Class at
Publication: |
62/498 ;
165/174 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F28F 9/02 20060101 F28F009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 17, 2008 |
CN |
200810008427.0 |
Claims
1. A heat exchanger comprising: a plurality of tubes, wherein heat
is exchanged between a first fluid and a second fluid in the
plurality of tubes; an inlet manifold to direct the first fluid
into the plurality of tubes at a third direction; and a distributor
tube located within the inlet manifold, wherein the distributor
tube includes a short tube including a plurality of first orifices
that direct the first fluid into the inlet manifold at a first
direction and a long tube including a plurality of second orifices
that direct the first fluid into the inlet manifold at a second
direction.
2. The heat exchanger as recited in claim 1 wherein the heat
exchanger is a microchannel evaporator.
3. The heat exchanger as recited in claim 1 wherein the plurality
of tubes each include a flattened portion.
4. The heat exchanger as recited in claim 1 wherein the distributor
tube includes a flow splitter that directs half of the first fluid
into the short tube and the other half of the first fluid into the
long tube.
5. The heat exchanger as recited in claim 1 further including an
outlet manifold, wherein the plurality of tubes fluidly connect the
inlet manifold and the outlet manifold.
6. The heat exchanger as recited in claim 1 wherein the short tube
and the long tube are substantially parallel.
7. The heat exchanger as recited in claim 1 wherein the first fluid
enters the short tube and the long tube at a first end, and an
opposing second end of each of the short tube and the long tube are
blocked with a stop.
8. The heat exchanger as recited in claim 1 wherein the first fluid
is refrigerant and the second fluid is air, and the refrigerant
flows through the plurality of tubes and the air passes over the
plurality of tubes.
9. The heat exchanger as recited in claim 1 wherein the plurality
of first orifices and the plurality of second orifices are arranged
in a linear configuration.
10. The heat exchanger as recited in claim 1 wherein an angle
between the first direction and the third direction is
substantially equal to another angle between the second direction
and the third direction, wherein the first direction is different
from the second direction.
11. The heat exchanger as recited in claim 10 wherein the angle and
the another angle are each approximately 45.degree. to 315.degree.
clockwise from the third direction.
12. The heat exchanger as recited in claim 1 wherein the plurality
of first orifices are located in one section of the distributor
tube and the plurality of second orifices are located in another
section of the distributor tube.
13. (canceled)
14. The heat exchanger as recited in claim 12 wherein the first
fluid flows through the one section and then through the another
section, and there are none of the plurality of second orifices in
the one section of the distributor tube.
15. The heat exchanger as recited in claim 12 wherein the short
tube is located in the one section of the distributor tube and the
long tube is located in both the one section and the another
section of the distributor tube.
16. A refrigeration system comprising: a compressor for compressing
a refrigerant; a condenser for cooling the refrigerant; an
expansion device for expanding the refrigerant; and a microchannel
evaporator for heating the refrigerant, wherein the microchannel
evaporator includes a plurality of tubes, an inlet manifold to
direct a first fluid into the plurality of tubes at a third
direction, and a distributor tube located within the inlet
manifold, wherein the distributor tube includes a short tube
including a plurality of first orifices that direct the first fluid
into the inlet manifold at a first direction and a long tube
including a plurality of second orifices that direct the first
fluid into the inlet manifold at a second direction.
17. The refrigeration system as recited in claim 16 wherein the
short tube and the long tube are substantially parallel.
18. The refrigeration system as recited in claim 16 wherein the
first fluid enters the short tube and the long tube at a first end,
and an opposing second end of each of the short tube and the long
tube are blocked with a stop.
19. The refrigeration system as recited in claim 16 wherein the
plurality of first orifices and the plurality of second orifices
are arranged in a linear configuration.
20. The refrigeration system as recited in claim 16 wherein an
angle between the first direction and the third direction is
substantially equal to another angle between the second direction
and the third direction, wherein the first direction is different
from the second direction.
21. (canceled)
22. (canceled)
23. (canceled)
24. The refrigeration system as recited in claim 21 wherein the
short tube is located in the one section of the distributor tube
and the long tube is located in both the one section and the
another section of the distributor tube.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to a microchannel heat
exchanger including an inlet manifold and a distributor tube.
[0002] A microchannel heat exchanger (MCHX) includes flat tubes
that extend between an inlet manifold and an outlet manifold.
Refrigerant flows through the flat tubes and exchanges heat with
air that passes over the tubes.
[0003] Maldistribution of two-phase refrigerant in the flat tubes
can be a problem. A distributor tube can be used to decrease
maldistribution of the refrigerant in the inlet manifold. The
distributor tube includes an inlet, an outlet and orifices.
Refrigerant enters the tube through the inlet, and the outlet is
blocked to discharge the refrigerant through the orifices. The
build-up of pressure in the distributor tube causes the refrigerant
to equally distribute along the length of the distributor tube. The
orifices are appropriately sized to cause a pressure drop or
build-up in the distributor tube. The distributor tube and the
orifices are also sized appropriately to reduce the amount of
separation of vapor refrigerant and liquid refrigerant in the
two-phase refrigerant flow.
[0004] However, when the inlet manifold is long (such as greater
than 800 mm), the pressure drop along the length of the distributor
tube will be uneven, and the refrigerant will not equally
distribute along the length of the distributor tube.
SUMMARY OF THE INVENTION
[0005] Exemplary embodiments of the invention include a heat
exchanger including tubes and an inlet manifold to direct a first
fluid into the tubes at a third direction. Heat is exchanged
between the first fluid and a second fluid in the tubes. The heat
exchanger also includes a distributor tube located within the inlet
manifold. The distributor tube includes a short tube including a
plurality of first orifices that direct the first fluid into the
inlet manifold at a first direction, and a long tube including a
plurality of second orifices that direct the first fluid into the
inlet manifold at a second direction.
[0006] Further exemplary embodiments include a refrigerant system
including a compressor for compressing a refrigerant, a condenser
for cooling the refrigerant, an expansion device for expanding the
refrigerant, and a microchannel evaporator for heating the
refrigerant. The microchannel evaporator includes tubes, an inlet
manifold to direct the refrigerant into the tubes at a third
direction, and a distributor tube located within the inlet
manifold. The distributor tube includes a short tube including a
plurality of first orifices that direct the refrigerant into the
inlet manifold at a first direction and a long tube including a
plurality of second orifices that direct the refrigerant into the
inlet manifold at a second direction.
[0007] These and other features of the present invention will be
best understood from the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The various features and advantages of the invention will
become apparent to those skilled in the art from the following
detailed description of the currently preferred embodiment. The
drawings that accompany the detailed description can be briefly
described as follows:
[0009] FIG. 1 illustrates a prior art refrigeration system;
[0010] FIG. 2 illustrates a microchannel evaporator;
[0011] FIG. 3 illustrates a side view of a distributor tube;
[0012] FIG. 4 illustrates a perspective view of an inlet manifold
with the distributor tube shown in phantom; and
[0013] FIG. 5 illustrates a cross-sectional view of the inlet
manifold taken along line 5-5 of FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] FIG. 1 illustrates a refrigeration system 20 including a
compressor 22, a condenser 24, an expansion device 26, and an
evaporator 28. Both the condenser 24 and the evaporator 28 are heat
exchangers and may be microchannel heat exchangers. In the example
shown, the evaporator 28 is the microchannel heat exchanger.
Refrigerant circulates through the closed circuit refrigeration
system 20.
[0015] A heat pump 35 can be employed to reverse the flow of the
refrigerant through the refrigeration system 20. When the heat pump
35 operates, the evaporator 28 functions as a condenser, and the
condenser 24 functions as an evaporator.
[0016] The refrigerant exits the compressor 22 at a high pressure
and a high enthalpy and flows through the condenser 24. In the
condenser 24, the refrigerant rejects heat to air and exits the
condenser 24 at a low enthalpy and a high pressure. A fan 30
directs the air through the condenser 24. The cooled refrigerant
then passes through the expansion device 26, expanding the
refrigerant to a low pressure. After expansion, the refrigerant
flows through the evaporator 28. In the evaporator 28, the
refrigerant accepts heat from air, exiting the evaporator 28 at a
high enthalpy and a low pressure. A fan 32 blows air through the
evaporator 28. The refrigerant then flows to the compressor 22,
completing the cycle.
[0017] FIG. 2 shows the evaporator 28. The evaporator 28 includes
an inlet manifold 40 and an outlet manifold 42 that extend along an
axis X. The inlet manifold 40 includes a body portion 43 and
openings 41 and has a length d. A plurality of flat tubes 44 having
a length c extend between the manifolds 40 and 42 along an axis Y.
The axis X is substantially perpendicular to the axis Y. Each of
the openings 41 of the inlet manifold 40 aligns with one of the
flat tubes 44.
[0018] Refrigerant from the expansion device 26 flows into the
inlet manifold 40. The refrigerant from the inlet manifold 40 flows
through the openings 41, into the plurality of flat tubes 44 and
accepts heat from air 46 flowing over the flat tubes 44. The
evaporator 28 can also include a plurality of fins 48 having
louvers positioned between the flat tubes 44 to aid in heat
transfer between the refrigerant and the air. The refrigerant then
flows into the outlet manifold 42 through openings 45 and is
directed to the compressor 22 through an outlet opening 70.
[0019] As shown in FIGS. 3 and 4, a distributor tube 34 including a
short tube 34a and a long tube 34b is located in the body portion
43 of the inlet manifold 40. A y-shaped flow splitter 52 is
attached to the distributor tube 34. The flow splitter 52 includes
an inlet portion 56 and two parallel outlet portions 54a and 54b.
An inlet tube 50 is in fluid communication with the inlet portion
52, and the short tube 34a and the long tube 34b are in fluid
communication with the outlet portions 54a and 54b, respectively.
In one example, the tubes 34a and 34b are parallel to each other
and to the inlet tube 50.
[0020] The tube 34a includes a first end 62a connected to the
outlet portion 54a of the flow splitter 52 and an opposing second
end 64a that is blocked by a stop 60a. The tube 34b includes a
first end 62b connected to the outlet portion 54b of the flow
splitter 52 and an opposing second end 64b that is blocked by a
stop 60b. The short tube 34a has a first length a, and the long
tube 34b has a second length b. That is, the first length a is less
than the second length b. The first length a of the short tube 34a
is approximately 30-70% of the second length b of the long tube
34b, considering the pressure balance within the tubes 34a and
34b.
[0021] In one example, the second length b of the long tube 34b is
approximately equal to the length d of the inlet manifold 40.
However, the second length b of the long tube 34b can be slightly
less than the length d of the inlet manifold 40, such as
approximately 94 to 100% of the length d of the inlet manifold
40.
[0022] The second end 64a of the short tube 34a aligned with a
location 71 of the long tube 34b. That is, the location 71 on the
long tube 34b is substantially between the ends 62b and 64b of the
long tube 34b. In one example, the location 71 is substantially in
the middle of the ends 62b and 64b.
[0023] The tubes 34a and 34b each include orifices 58a and 58b,
respectively. The orifices 58a and 58b are appropriately sized to
cause a pressure drop or a pressure build-up in the distributor
tube 34 and to reduce the separation of vapor refrigerant and
liquid refrigerant in the two-phase refrigerant flow. The orifices
58a of the short tube 34a are linearly aligned and are located in a
section 75 defined between the ends 62a and 64a of the short tube
34a. The orifices 58b of the long tube 34b are linearly aligned and
are located in a section 73 defined between the location 71 and the
end 64b of the long tube 34b. Therefore, the orifices 58a and 58b
are located in different sections 73 and 75 of the distributor tube
34. The orifices 58a and 58b are aligned such that they extend
along a straight line substantially parallel to the lengths a and b
of the tubes 34a and 34b, respectively.
[0024] As shown in FIG. 5, the orifices 58a direct refrigerant
flowing through the short tube 34a into the inlet manifold 40 at a
first direction E, and the orifices 58b direct refrigerant flowing
through the long tube 34b into the inlet manifold 40 at a second
direction F. The refrigerant directed into the inlet manifold 40 is
then directed through the openings 41 and into one of the flat
tubes 44 for heat exchange with the air at a third direction G.
[0025] In one example, the first direction E and the second
direction F are oriented at an angle relative to the third
direction G. In one example, the first direction E and the second
direction F can be oriented at an angle that is approximately
45.degree. to 315.degree. clockwise from the third direction G.
However, the orifices 58a and 58b can be located at any number of
locations and are located in a way that helps to induce and cause
additional mixing when the refrigerant is discharged from the tubes
34a and 34b.
[0026] In one example shown in FIG. 5, the second direction F is
approximately 135.degree. clockwise relative to the third direction
G, and the first direction E is approximately 225.degree. clockwise
(or 135.degree. counter-clockwise) relative to the third direction
G.
[0027] The refrigerant exiting the expansion device 26 is in two
phases and includes approximately 80% vapor and approximately 20%
liquid by mass. The density of the liquid refrigerant is
approximately 10-100 times greater than the density of the vapor
refrigerant. Therefore, the vapor refrigerant flows faster than the
liquid refrigerant.
[0028] Refrigerant from the expansion device 26 enters the
distributor tube 34 through the inlet tube 50 and flows into the
tubes 34a and 34b. The flow splitter 52 divides the refrigerant
entering the inlet manifold 40 such that approximately 50% enters
the short tube 34a and approximately 50% enters the long tube 34b.
As the second ends 64a and 64b of the tubes 34a and 34b,
respectively, are blocked by the stops 60a and 60b, respectively,
the refrigerant is forced through the orifices 58a and 58b and into
the inlet manifold 40. The increase in pressure causes the
refrigerant to distribute equally along the length d of the inlet
manifold 40.
[0029] The refrigerant entering the short tube 34a is equally
distributed to the section 75 through the orifices 58a, and the
refrigerant entering the long tube 34b is equally distributed to
the section 73 through the orifices 58b. The refrigerant is equally
distributed to each section 73 and 75 as half of the refrigerant is
provided to each tube 34a and 34b. An equal distribution of
refrigerant is possible as half of the refrigerant is provided to
each half of the length d of the inlet manifold 40 for distribution
to the flat tubes 44. As a portion of the refrigerant is
specifically designated for distribution to a specific section 73
and 75 of the inlet manifold 40, a better distribution of
refrigerant is possible in each section 73 and 75 of the inlet
manifold 40.
[0030] By employing a short tube 34a and a long tube 34b,
maldistribution of the refrigerant can be prevented, especially if
the length d of the inlet manifold 40 is very long, such as greater
than 800 mm. For example, if the length d of the inlet manifold 40
is 800 mm, half of the refrigerant would be designated to each 400
mm section of the inlet manifold 40, providing a more even
distribution of refrigerant in each 400 mm section, as each 400 mm
section is designated to receive half of the refrigerant.
[0031] The foregoing description is only exemplary of the
principles of the invention. Many modifications and variations of
the present invention are possible in light of the above teachings.
The preferred embodiments of this invention have been disclosed,
however, so that one of ordinary skill in the art would recognize
that certain modifications would come within the scope of this
invention. It is, therefore, to be understood that within the scope
of the appended claims, the invention may be practiced otherwise
than as specifically described. For that reason the following
claims should be studied to determine the true scope and content of
this invention.
* * * * *