U.S. patent application number 10/929466 was filed with the patent office on 2005-03-10 for air conditioner comprising heat exchanger and means for switching cooling cycle.
This patent application is currently assigned to LG ELECTRONICS INC.. Invention is credited to Chin, Sim Won, Hong, Ki Soo, Jung, In Hwa, Lee, Jung Woo, Moon, Dong Soo.
Application Number | 20050050910 10/929466 |
Document ID | / |
Family ID | 34139415 |
Filed Date | 2005-03-10 |
United States Patent
Application |
20050050910 |
Kind Code |
A1 |
Moon, Dong Soo ; et
al. |
March 10, 2005 |
Air conditioner comprising heat exchanger and means for switching
cooling cycle
Abstract
The present invention relates to an air conditioner capable of
performing heat exchange of refrigerant and cooling and heating
operations. According to the invention, a dual-tube heat exchanger
is disposed at the entrance of a compressor and a means for
switching a cooling cycle is installed between an outdoor heat
exchanger including a condenser and an indoor heat exchanger
including an evaporator so that in an air conditioning mode, heat
change between mid-temperature, high-pressure liquid refrigerant at
the exit of the condenser and low-temperature, low-pressure
superheated refrigerant at the exit of the evaporator is performed
more effectively and as a result of this, super heating of the
liquid refrigerant at the exit of the condenser is increased,
refrigerant flow characteristics of an expansion unit are improved,
and enthalpy at the entrance side of the evaporator is reduced,
causing a greater enthalpy difference at the entrance and exit of
the evaporator and improving air conditioning capacity overall.
Moreover, the heat exchanger of the present invention has a dual
tube structure and uses a counter flow or parallel flow for
performing heat exchange. In the dual tube structure, a tube and a
core of the heat exchanger form a line or surface contact and
heating capacity is therefore enhanced.
Inventors: |
Moon, Dong Soo; (Seoul,
KR) ; Chin, Sim Won; (Gwangmyeong-si, KR) ;
Hong, Ki Soo; (Anyang-si, KR) ; Lee, Jung Woo;
(Seoul, KR) ; Jung, In Hwa; (Seoul, KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
34139415 |
Appl. No.: |
10/929466 |
Filed: |
August 31, 2004 |
Current U.S.
Class: |
62/324.1 ;
62/513 |
Current CPC
Class: |
F25B 13/00 20130101;
F28D 7/106 20130101; F25B 40/00 20130101; F28F 1/40 20130101; F28F
13/06 20130101 |
Class at
Publication: |
062/324.1 ;
062/513 |
International
Class: |
F25B 027/00; F25B
013/00; F25B 041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2003 |
KR |
62111/2003 |
Sep 15, 2003 |
KR |
63664/2003 |
Nov 5, 2003 |
KR |
77857/2003 |
Claims
1. An air conditioner comprising: a condenser; an evaporator; a
compressor; a device that switches a flow line of refrigerant
discharged from the compressor; and a heat exchanger for performing
heat exchange disposed before the compressor.
2. The air conditioner according to claim 1, wherein the heat
exchanger is a dual-tube heat exchanger.
3. An air conditioner comprising: a condenser; an evaporator; a
compressor; a device that switches a refrigerant line; a heat
exchanger for performing heat exchange disposed before the
compressor; and a device that changes a flow line of refrigerant
discharge from the condenser or evaporator and makes the flow line
pass through the heat exchanger.
4. The air conditioner according to claim 3, wherein the device
that changes the flow line of the refrigerant is a check valve.
5. The air conditioner according to claim 4, wherein the check
valve is comprised of four combined valves.
6. The air conditioner according to claim 3, wherein the device
that switches the flow line of the refrigerant is four sides.
7. An air conditioner comprising: a condenser; an evaporator; a
compressor; and a heat exchanger for performing heat exchange
disposed before the compressor, wherein at least two refrigerant
flow lines are formed in the heat exchanger and a structure for
heat transfer between refrigerants flowing in the refrigerant flow
lines forms a certain area of surface contact.
8. The air conditioner according to claim 7, wherein at least two
refrigerant flow lines comprises: a first tube where a first
refrigerant flows in; a second tube where a second refrigerant
flows in; and a structure connected to the first tube or the second
tube and forming a certain area of surface contact with the first
tube or the second tube.
9. The air conditioner according to claim 8, wherein the structure
forming the certain area of surface contact with the first tube or
the second tube is connected to the first tube or the second tube
in the longitudinal direction and comprises a sector-shaped core
forming a surface contact with an internal circumferential surface
of the first tube or the second tube.
10. The air conditioner according to claim 8, wherein the
sector-shaped core is formed by connecting vertical side and
horizontal side of the core in an equilateral triangle
structure.
11. The air conditioner according to claim 10, wherein to connect
neighboring vertical sides, an upper horizontal long side and a
lower short horizontal side of the core are successively connected
to the vertical side in zigzags, and by applying the short
horizontal side at the center as an origin, the long horizontal
side at the end is spread out in a sector shape.
12. The air conditioner according to claim 9, wherein the first
tube or the second tube is split into at least one area and the
sector-shaped core is installed therein, respectively.
13. The air conditioner according to claim 8, wherein the structure
for forming the surface contact with the first tube or the second
tube is connected to the first tube or the second tube in the
longitudinal direction, and comprises a wave-shaped core forming a
partial surface contact with the internal circumferential surface
of the first tube or the second tube.
14. The air conditioner according to claim 13, wherein resistance
and fluid vortex are generated by the wave-shaped core and thus,
heat conductivity is improved.
15. The air conditioner according to claim 9, wherein an expansion
tube is connected in the longitudinal direction to the center of
the core in order to expand the surface contact between the first
tube or the second tube and the sector-shaped tube.
16. The air conditioner according to claim 15, wherein jaws are
formed at both ends of the expansion tube so that both ends of the
core are suspended thereby.
17. The air conditioner according to claim 9, wherein at least two
cores are inside the first tube or the second tube.
18. The air conditioner according to claim 17, wherein the cores
inside the first tube or the second tube are connected in
zigzags.
19. The air conditioner according to claim 8, wherein the structure
for forming the surface contact with the first tube or the second
tube is connected to the first tube or the second tube in the
longitudinal direction, and comprises a spiral-shaped core forming
a line or surface contact with the internal circumferential surface
of the first tube or the second tube.
20. The air conditioner according to claim 19, wherein the internal
core is formed of a plurality of folded surfaces.
21. The air conditioner according to claim 20, wherein the
plurality of folded surfaces is formed by bending or folding.
22. The air conditioner according to claim 20, wherein resistance
and fluid vortex are generated by the folded core into the plural
surfaces and thus, heat conductivity is improved.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates in general to an air
conditioner capable of performing heat exchange of refrigerant and
cooling and heating operations. More particularly, the present
invention relates to an air conditioner in which a dual-tube heat
exchanger is disposed at the entrance of a compressor and a means
for switching a cooling cycle is installed between an outdoor heat
exchanger including a condenser and an indoor heat exchanger
including an evaporator so that in an air conditioning mode, heat
change between mid-temperature, high-pressure liquid refrigerant at
the exit of the condenser and low-temperature, low-pressure
superheated refrigerant at the exit of the evaporator is performed
more effectively and as a result of this, super heating of the
liquid refrigerant at the exit of the condenser is increased,
refrigerant flow characteristics of an expansion unit are improved,
and enthalpy at the entrance side of the evaporator is reduced,
causing a greater enthalpy difference at the entrance and exit of
the evaporator and improving air conditioning capacity overall.
[0003] In addition, the heat exchanger of the present invention has
a dual tube structure and uses a counter flow or parallel flow for
performing heat exchange. In the dual tube structure, a tube and a
core of the heat exchanger form a line or surface contact and
heating capacity is therefore enhanced.
[0004] 2. Discussion of the Background Art
[0005] In general, the main function of an indoor air
conditioning/heating machine, for example an air conditioner or a
heat pump, is to maintain a desired indoor temperature regardless
of the outside temperature.
[0006] Since the indoor temperature is set up as desired, a
comfortable dwelling environment is created.
[0007] FIG. 1 illustrates a refrigeration cycle according to a
related art.
[0008] As shown in FIG. 1, a refrigeration unit includes a
compressor 1 for changing low-temperature, low-pressure vapor
refrigerant to high-temperature, high-pressure vapor refrigerant; a
condenser 2 for changing the high-temperature, high-pressure vapor
refrigerant from the compressor 1 to mid-temperature, high-pressure
liquid refrigerant; and an expansion valve 13 for changing the
mid-temperature, high-pressure liquid refrigerant from the
condenser 12 to low-temperature, low-pressure liquid refrigerant;
and an evaporator 4 for changing the phase of the low-temperature,
low-pressure liquid refrigerant to vapor and absorbing heat of the
outside. Here, each component is connected to each other through a
refrigerant tube.
[0009] The refrigeration unit absorbs heat of the outside through
the evaporator and extracts heat outdoors through the condenser.
Because of this, the refrigeration unit is often applied to a
refrigerator or an air conditioner for purpose of keeping food
fresh or providing cool (warm) comfort by air conditioning/heating
indoor.
[0010] FIG. 2 illustrates a cooling cycle of an air conditioner
according to a related art.
[0011] As shown in FIG. 2, low-temperature, low-pressure vapor
refrigerant flown in a compressor 1 from an indoor heat exchanger 4
is compressed to high-temperature, high-pressure vapor refrigerant
through the operation of the compressor 1, and at the same time, is
discharged to an outdoor heat exchanger 2 through a four-way valve
5 that is switched for activating the cooling cycle. The
refrigerant discharged to the outdoor heat exchanger 2 circulates
inside the outdoor heat exchanger 2 and experiences heat exchange
with outdoor air sucked in the outdoor heat exchanger through an
outdoor fan 7. As a result of this, the refrigerant undergoes a
phase change and becomes mid-temperature, high-pressure liquid
refrigerant.
[0012] The phase-changed refrigerant is discharged to an expansion
valve 3 and simultaneously circulates inside of the expansion valve
3 where the refrigerant is compressed to slow-temperature,
low-pressure liquid refrigerant to be more easily evaporated, and
is discharged to the indoor heat exchanger 4. The refrigerant
discharged to the indoor exchanger 4 experiences heat exchange with
ambient air of the indoor heat exchanger and undergoes again a
phase change to become low-temperature, low-pressure vapor state
and then flows back into the compressor 1 through the four-way
valve 5.
[0013] Therefore, the ambient air that underwent heat exchange in
the indoor heat exchanger 4 with the compressed refrigerant through
the expansion valve 3 loses its heat to the refrigerant and becomes
noticeably chilly. This cold air is sucked in to the inside through
the indoor fan 6 and thus, the cooling cycle of the air conditioner
ends.
[0014] FIG. 3 illustrates a heating cycle of an air conditioner
according to a related art.
[0015] As shown in FIG. 3, the heating cycle is opposite to the
cooling cycle described before. That is, low-temperature,
low-pressure vapor refrigerant flown in a compressor 1 from an
outdoor heat exchanger 2 is compressed to high-temperature,
high-pressure vapor refrigerant through the operation of the
compressor 1 and at the same time, is discharged to an indoor heat
exchanger 4 through a switched four-way valve 5. In the indoor heat
exchanger 4, the vapor refrigerant experiences heat exchange with
ambient air of the indoor heat exchanger 4 and undergoes a phase
change and becomes mid-temperature, high-pressure liquid state and
is charged to an expansion valve 3. At this time, the ambient air
that experienced heat exchange with the high-temperature,
high-pressure refrigerant changes to hot air by taking heat from
the refrigerant and is sucked into the inside through an indoor fan
6, resultantly raising the indoor temperature.
[0016] Further, the refrigerant discharged to the expansion valve
14 is compressed to low-temperature, low-pressure liquid state to
be evaporated better in the outdoor heat exchanger 2 and then is
discharged to the outdoor heat exchanger 2. In the outdoor heat
exchanger 2 the refrigerant experiences heat exchange with outdoor
air flown in the outdoor heat exchanger and undergoes a phase
change and becomes low-temperature, low-pressure vapor state. At
the end, this phase changed refrigerant flows back into the
compressor 1 through the four-way valve.
[0017] FIG. 4 is a schematic diagram illustrating an air
conditioning/heating device according to a related art.
[0018] As illustrated in FIG. 4, in operation of the air
conditioning device, a refrigerant gas discharged from a compressor
1 is separated from oil through an oil separator 8, and this
oil-free refrigerant gas flows in an outdoor heat exchanger 2 via a
four-way valve 5 and becomes low-temperature, low-pressure
refrigerant while passing through an expansion valve and then flows
in an indoor heat exchanger 4.
[0019] The refrigerant gas evaporated in the indoor heat exchanger
4 experiences heat exchange with indoor air and flows in an
accumulator 9 through the four-way valve 5. This refrigerant gas in
the accumulator 9 is sucked in the compressor 1 and circulates
therein continuously.
[0020] On the other hand, in operation of the heating device, a
refrigerant gas discharged from the compressor 1 is separated from
oil through the oil separator 8. This oil-free refrigerant gas
flows in the indoor heat exchanger 4 via the four-way valve 5 and
is condensed, experiencing heat exchange with indoor air. Later,
the refrigerant travels in the expansion valve and changes to
low-temperature, low-pressure state and is evaporated while passing
through the outdoor heat exchanger 2.
[0021] The evaporated refrigerant gas flows in the accumulator 9
via the four-way valve 5. Then the refrigerant is sucked in the
compressor 1 and circulates therein.
[0022] FIG. 5 illustrates a dual-tube heat exchanger of an air
conditioner according to a related art.
[0023] The air conditioner of FIG. 5 is characterized of having a
dual-tube heat exchanger 10 between a condenser 1 (outdoor heat
exchanger) and an expansion unit 3.
[0024] A compressed refrigerant through a compressor 1 is
transferred to the outdoor heat exchanger 2 and experiences heat
exchange with outdoor air in the outdoor heat exchanger 2 and also
in the dual-tube heat exchanger 10. Then the refrigerant flows in
an evaporator 4 (indoor heat exchanger) via an expansion unit
3.
[0025] Through heat exchange with indoor air, the indoor
temperature maintains a pre-set low temperature and later, the
refrigerant experiences heat exchange while traveling in the
dual-tube heat exchanger 10. Then, the refrigerant flows back into
the compressor 1 and recirculates therein.
[0026] In the dual-tube heat exchanger, the refrigerant flow of the
expansion unit changes depending on how to increase sub cooling of
the outdoor heat exchanger and characteristics of the refrigerant
flow are also subject to enthalpy difference at the entrance and
exit of the evaporator, which in turn affects the entire system
efficiency, e.g., the coefficient of performance (COP) of the air
conditioner. Also, for this type of heat exchanger, preventing
liquid from entering the compressor is influenced by a method for
increasing super heating at the entrance of the compressor, and the
temperature increase at the entrance of the compressor has a great
impact on the performance of the heat exchanger at high speed.
[0027] The following will now explain relevant techniques for the
heat exchanger.
[0028] FIG. 6 illustrates a related art liquid-vapor heat
exchanger.
[0029] Referring to FIG. 6, the liquid/vapor heat exchanger 2
includes a first tube 11 inside and a second tube 12 outside, two
being connected as a dual-tube type. One end of the first tube 11
is connected to an entrance P1 of an evaporator 13 and the other
end is connected to an entrance P2 of a compressor 14. Thus
low-temperature, low-pressure vapor is sucked in the heat exchanger
2 and experiences heat exchange with liquid flowing into the second
tube 12 and then is transferred to the compressor 14.
[0030] That is, the first tube 11 is connected to the entrance P1
of the evaporator and the entrance P2 of the compressor and
low-temperature, low-pressure vapor runs therein. The second tube
12, on the other hand, is connected to an entrance P3 of a
condenser 15 and an entrance P4 of an expansion valve 16 and the
refrigerant flowing inside the first tube 12 and mid-temperature,
high-pressure liquid as counter flow (or parallel flow) runs
therein, consequently changing the low-temperature vapor in the
first tube to mid-temperature liquid.
[0031] FIG. 7 and FIG. 8 illustrate a related art liquid-vapor heat
exchanger 2.
[0032] As shown in FIGS. 7 and 8, a radial shaped core 17 is
inserted in an inner space 11a of a first tube 11 to perform heat
exchange on a refrigerant flowing inside the first tube 11.
[0033] As the name implies, the core 17 inserted into the first
tube 11 has a radial shape, that is, a plurality of pins is
separated by a constant angle from the center and each pin is
protruded perpendicularly.
[0034] However, each of the pins of the core 17 is in line contact
with the internal circumferential surface of the first tube 11, so
heating efficiency thereof is pretty low and it is difficult to
manufacture the core itself
[0035] Meanwhile, inside surface 12a of the second tube 12 runs
mid-temperature, high-pressure liquid.
[0036] FIG. 9 illustrates another embodiment of a related art
liquid-vapor heat exchanger 2.
[0037] As shown in FIG. 9, there is a wave-shaped (".about." shape)
tube 18 between a first tube 11 and a second tube 12, to improve
heat exchange between liquid flowing into the second tube and a
refrigerant flowing into the first tube 11. Other reference
numerals shown in FIG. 9 correspond to those in FIG. 6.
[0038] Unfortunately this type of heat exchanger also poses a
problem like low heating performance.
SUMMARY OF THE INVENTION
[0039] An object of the invention is to solve at least the above
problems and/or disadvantages and to provide at least the
advantages described hereinafter.
[0040] Accordingly, one object of the present invention is to solve
the foregoing problems by providing a structure, in which a
dual-tube heat exchanger is disposed at an entrance of a compressor
and a refrigerant flow switching unit is disposed between an indoor
heat exchanger and an outdoor heat exchanger, thereby improving
refrigerant flow of an expansion unit by increasing super heating
of the outdoor heat exchanger and by increasing enthalpy increase
at an entrance of an evaporator.
[0041] Another object of the present invention is to prevent liquid
from entering a compressor by increasing super heating at the
entrance of the compressor and prevent temperature increase at the
entrance of the compressor.
[0042] Another object of the invention is to provide a liquid-vapor
heat exchanger including a core that is in surface contact with the
internal circumferential surface of an inner or outer tube of the
liquid-vapor heat exchanger.
[0043] Another object of the invention is to provide a dual-tube
liquid-vapor heat exchanger, in which a vapor refrigerant flows in
an inside or outside tube and liquid flows in an outside or inside
tube as counter flow or parallel flow for heat conversion between
the vapor refrigerant and the liquid and heating performance is
greatly improved by a radial shaped or sector-shaped core inserted
into the inside or outside tube.
[0044] Another object of the invention is to provide to a
liquid-vapor heat exchanger capable of enhancing heating
performance by employing a sector-shaped to be expanded by
expansion tube to the center of a sector-shaped core, thereby
causing the core to be in surface contact with a tube.
[0045] Another object of the invention is to provide to a
liquid-vapor heat exchanger, in which an inside or outside tube is
split in a longitudinal direction into at least one area and a
section-shaped core is connected to each area in zigzags.
[0046] Another object of the invention is to provide a liquid-vapor
heat exchanger with an improved heating capacity, in which a
spiral-shaped internal core with folded surfaces is installed in
the tube and fluid vortex generated by the folded surfaces of the
internal core inside the first tube activates heat exchange between
the outside surface of the internal core and the internal
circumferential surface of the first tube.
[0047] The foregoing and other objects and advantages are realized
by providing an air conditioner including a condenser; an
evaporator; a compressor; a means for switching a flow line of
refrigerant discharged from the compressor; and a heat exchange
means for performing heat exchange disposed before the
compressor.
[0048] According to another aspect of the invention, an air
conditioner includes: a condenser; an evaporator; a compressor; a
means for switching a refrigerant line; a heat exchange means for
performing heat exchange disposed before the compressor; and check
valve or four-side as a separate means for switching a flow line of
refrigerant discharge from the condenser or evaporator and making
the flow line pass through the heat exchanger.
[0049] According to another aspect of the invention, an air
conditioner includes: a condenser; an evaporator; a compressor; and
a heat exchange means for performing heat exchange disposed before
the compressor, wherein at least two refrigerant flow lines are
formed in the heat exchanger and a means for heat transfer between
refrigerants flowing in the refrigerant flow lines forms a certain
area of surface contact.
[0050] According to another aspect of the invention, a refrigerant
flow line includes: a first tube where a first refrigerant flows
in; a second tube where a second refrigerant flows in; and a means
connected to the first tube or the second tube and forming a
certain area of surface contact with the first tube or the second
tube.
[0051] According to another aspect of the invention, an expansion
tube is connected in the longitudinal direction to the center of
the core in order to expand the surface contact between the first
tube or the second tube and the sector-shaped tube.
[0052] According to another aspect of the invention, a
spiral-shaped core is connected to a first tube where a first
refrigerant flows in and to a second tube where a second
refrigerant flows in, and forms a line or surface contact with the
internal circumferential surface of the first tube or the second
tube.
[0053] According to the present invention, increasing sub cooling
of the outdoor heat exchanger increases refrigerant flow of the
expansion unit, improves refrigerant flow characteristics in
dependence of enthalpy difference at the entrance and exit of the
evaporator and thus, enhances the total efficiency of the system.
Increasing super heating at the entrance of the compressor prevents
liquid (or fluid) from entering into the compressor, prevents
temperature increase at the entrance of the compressor and thus,
ensures excellent performance even at high speed operation.
[0054] Also, by connecting the easy-to-manufacture, sector-shaped
core to the inside of the tube where vapor refrigerant flows,
surface contact is formed between the core and the tube surface and
this in turn improves heating performance of the refrigerant that
is changed to liquid-vapor phase through the surface contact with
the tube surface.
[0055] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objects and advantages
of the invention may be realized and attained as particularly
pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The invention will be described in detail with reference to
the following drawings in which like reference numerals refer to
like elements wherein:
[0057] FIG. 1 illustrates a refrigeration cycle according to a
related art;
[0058] FIG. 2 illustrates a cooling cycle of an air conditioner
according to a related art;
[0059] FIG. 3 illustrates a heating cycle of an air conditioner
according to a related art;
[0060] FIG. 4 is a schematic diagram illustrating an air
conditioning/heating device according to a related art;
[0061] FIG. 5 illustrates a dual-tube heat exchanger in an air
conditioner according to a related art;
[0062] FIG. 6 illustrates a related art liquid-vapor heat
exchanger;
[0063] FIG. 7 and FIG. 8 illustrate one embodiment of a related art
liquid-vapor heat exchanger;
[0064] FIG. 9 illustrates another embodiment of a related art
liquid-vapor heat exchanger;
[0065] FIG. 10 is a schematic diagram of a heat exchanger of the
present invention, in which a check valve is used as a cooling
cycle switch unit;
[0066] FIG. 11 is a schematic diagram of a heat exchanger of FIG.
10 of the present invention, in which a four-way valve is used as a
cooling cycle switch unit;
[0067] FIG. 12 is a schematic diagram of a heat exchanger of FIGS.
10 and 11, in which neither check valve nor four-way valve is
mounted;
[0068] FIG. 13 is a perspective view of a liquid-vapor heat
exchanger according to one embodiment of the present invention;
[0069] FIG. 14 is an exploded view of a liquid-vapor heat exchanger
according to one embodiment of the present invention;
[0070] FIG. 15 illustrates a complete form of a liquid-vapor heat
exchanger according to one embodiment of the present invention;
[0071] FIG. 16 is a cross-sectional view of a liquid-vapor heat
exchanger according to one embodiment of the present invention;
[0072] FIGS. 17, 18, 19, and 20 illustrate a liquid-vapor heat
exchanger, respectively, according to another embodiment of the
present invention;
[0073] FIG. 21 and FIG. 22 are perspective exploded views of a
liquid-vapor heat exchanger of FIG. 20; and
[0074] FIG. 23 illustrates a ph diagram.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0075] The following detailed description will present an air
conditioner comprising a heat exchanger and a means for switching a
cooling cycle according to a preferred embodiment of the invention
in reference to the accompanying drawings.
[0076] FIG. 10 is a schematic diagram of a heat exchanger of the
present invention, in which a check valve is used as a cooling
cycle switch unit; FIG. 11 is a schematic diagram of the heat
exchanger of FIG. 10 of the present invention, in which a four-way
valve instead of the check valve is used as a cooling cycle switch
unit; and FIG. 12 is a schematic diagram of the heat exchanger of
FIGS. 10 and 11, in which neither check valve nor four-way valve is
mounted.
[0077] Referring to the FIGS. 10, 11 and 12, the air
conditioning/heating device includes an indoor heat exchanger, an
outdoor heat exchanger, a four-way valve and a compressor for
compressing refrigerant. More specifically, a dual-tube heat
exchanger 103 is disposed at the entrance of the compressor 101 and
refrigerant flow switch units 105, 106 are connected between the
indoor heat exchanger 104 and the outdoor heat exchanger 102 to
perform more effective heat exchange during the air
conditioning/heating operation. Also, when the cooling and heating
cycles are switched, the refrigerant flows to a fixed direction at
the entrance and exit of the dual-tube heat exchanger 103.
[0078] Particularly, the air conditioning/heating device of FIG. 10
is characterized of having a check valve 106 with a plurality of
valves as the refrigerant flow switch unit, while the air
conditioning/heating device of FIG. 11 is characterized of having a
four-way valve 107 instead of the check valve as the refrigerant
flow switch unit.
[0079] The following will not discuss the operation of the air
conditioning/heating device mounted with the dual-tube heat
exchanger 103 and the refrigerant flow switch unit.
[0080] During the air conditioning operation, mid-temperature,
high-pressure liquid refrigerant at the exit of a condenser
experiences heat exchange with low-temperature, low-pressure super
heated refrigerant at the exit of an evaporator, and as a result of
this, sub cooling of the liquid refrigerant at the exit of the
condenser is increased and a refrigerant flow characteristic of an
expansion unit is improved.
[0081] In other words, the greater sub cooling is, the more
refrigerant flow increases, and the lower the enthalpy at the
entrance of the evaporator becomes, making a bigger difference with
the enthalpy at the entrance and exit of the evaporator, which
consequently enhances air conditioning performance.
[0082] During the heating operation, mid-temperature, high-pressure
liquid refrigerant at the exit of a condenser experiences heat
exchange with low-temperature, low-pressure super heated
refrigerant at the exit of an evaporator, and as a result of this,
super heating at the entrance of the compressor is increased and
there is less possibility for liquid to enter the compressor.
Therefore, driving reliability of the compressor is improved.
[0083] More specifically, refrigerant at the entrance of the
evaporator experiences heat exchange with super heated refrigerant
at the exit of the evaporator, and as a result of this, super
heating at the entrance of the compressor, namely the exit of the
evaporator, is reduced and compression characteristics of the
compressor are enhanced. Particularly, by reducing super heating at
the entrance of the compressor during high frequency (Hz)
operation, it becomes possible to prevent super heating of the exit
of the compressor.
[0084] FIG. 12 is a schematic diagram of the heat exchanger of
FIGS. 10 and 11, in which neither check valve nor four-way valve is
mounted.
[0085] As depicted in FIG. 12, a dual-tube heat exchanger 103 is
installed between a four-way valve and the entrance of a compressor
101 so that mid-temperature, high-pressure liquid refrigerant at
the exit of a condenser experiences heat exchange with
low-temperature, low-pressure super heated refrigerant at the exit
of an evaporator. In consequence, sub cooling of the liquid
refrigerant at the exit of the condenser is increased and thus, the
refrigerant flow characteristic of an expansion unit is
improved.
[0086] In other words, the greater sub cooling is, the more
refrigerant flow increases, and the lower the enthalpy at the
entrance of the evaporator becomes, making a bigger difference with
the enthalpy at the entrance and exit of the evaporator, which
consequently enhances air conditioning performance.
[0087] Although the structure of FIG. 12 is simple, heat exchange
effect in heating mode is extremely low, compared to the one in air
conditioning mode.
[0088] FIG. 13 is a perspective view of a liquid-vapor heat
exchanger according to one embodiment of the present invention;
FIG. 14 is an exploded view of the liquid-vapor heat exchanger of
the present invention; FIG. 15 illustrates a complete form of a
liquid-vapor heat exchanger of the present invention; FIG. 16 is a
cross-sectional view of the liquid-vapor heat exchanger of the
present invention; and FIGS. 17, 18, 19, and 20 illustrates a
liquid-vapor heat exchanger, respectively, according to another
embodiment of the present invention.
[0089] Referring to FIGS. 13 through 16, the liquid-vapor heat
exchanger includes a first tube 108 having an entrance and an exit
111, 110, wherein low-temperature, low-pressure vapor refrigerant
flows; a second tube 109 having an entrance and an exit 113, 112
and disposed outside of the first tube 108, wherein
mid-temperature, high-pressure liquid refrigerant flows as counter
flow to heat the vapor refrigerant flowing inside the first tube
108; a sector-shaped core 130 housed in the first tube 108; and an
expansion tube 114 inserted into the center of the core 130 to
ensure that outside of the end portion of the core 130 is tightly
fitted to outside surface of the first tube 108.
[0090] Here, the expansion tube 114 has jaws 119 on both ends,
respectively, each with an inward nose projection as shown in FIG.
16, and is connected to the core 130 as one body.
[0091] The operation of the liquid-vapor heat exchanger with the
above constitution will be now explained with reference to
drawings.
[0092] Referring to FIGS. 13, 14 and 15, the internal first tube
108 and the external second tube 109 form a dual tube in the
longitudinal direction. The first tube 108 is connected to the exit
P1 of the evaporator 110 and performs heat exchange on the
low-temperature, low-pressure vapor refrigerant from the evaporator
and sends it to the entrance P2 of the compressor 111.
[0093] At this time, the mid-temperature, high-pressure liquid
flowing in the second tube 109 as counter flow or parallel flow
heats up the vapor refrigerant through the core formed inside the
first tube 108, thereby raising the vapor temperature inside of the
first tube 108 and increasing the pressure of the vapor.
[0094] Therefore, to improve heating performance of the first tube
108, there sits a heating means at the internal space of the first
tube 110 in a manner that the heating means makes a partial surface
contact in the longitudinal direction. The sector-shaped core 130
is a good example of the heating means.
[0095] As illustrated in FIGS. 14, 15 and 16, the core has a sector
shape, that is, a vertical side and a horizontal side 118, 119 are
connected to each other in an equilateral triangle shape, forming a
sector shape.
[0096] More specifically, to connect neighboring vertical sides
118, an upper horizontal long side 117 and a lower short horizontal
side 116 are successively connected to the vertical side 118 in
zigzags. Also, by applying the short horizontal side 116 at the
center as an origin, the long horizontal side 117 at the end is
spread out in a sector shape.
[0097] Here, the long horizontal side 117 at the end of the core
forms surface contact with the internal circumferential surface of
the first tube 108, thereby improving the heating performance of
the vapor refrigerant.
[0098] Also, to make the long horizontal side 117 at the end be
closely adhered to the internal circumferential surface of the
first tube 108, the expansion tube 114 passing through the inside
of the short horizontal side 116 at the center of the core is
connected in the longitudinal direction.
[0099] Referring to FIGS. 14 through 16, the expansion tube 114 is
longitudinally inserted into the center of the sector-shaped core
130 that is connected to the internal space 110 of the first tube
108.
[0100] Since the expansion tube 118 is inserted into the core, the
center of the core is expanded so that the entire core is pushed to
the outside of the first tube 108 and the long horizontal side 117
is closely adhered to the inner surface of the tube.
[0101] Inside of the expansion tube 114 is opened, and its radius
is preferably larger than the radius (or distance) from the center
of the core to the short horizontal side 116.
[0102] Therefore, the expansion tube 114, the sector-shaped core
130, and the first tube 108 are adhered in sequence to the inner
surface of the first tube 108.
[0103] In the above embodiment, the expansion tube 114 can be a
longitudinal tube or have another structure in which its inside is
opened and the core is expanded outward.
[0104] Both ends of the expansion tube 114, as shown in FIG. 16,
are the jaws 119, and each jaw is hooked on both ends of the short
horizontal side 116 of the core 130 to ensure that the core 130 and
the expansion tube 114 are tied up together.
[0105] The jaws 119 on the both ends of the expansion tube 114 are
protruded to connect the cores.
[0106] According to another embodiment, a plurality of expansion
tubes, each with a screw at the center, can be connected to the
jaws and they are hammered later, or the jaws are spaced apart for
the core to be inserted into grooves between the jaws and the short
horizontal side.
[0107] FIG. 17 illustrates a liquid-vapor heat exchanger 200
according to another embodiment of the present invention.
[0108] As shown in FIG. 17, a first tube 109 is divided into three
areas d1, d2, d3, and sector-shaped cores 130, 120, 121 are
inserted thereto, respectively, according to their sizes.
[0109] The above method is effective especially when it is
difficult to insert a single core in the longitudinal
direction.
[0110] In this embodiment, those three cores 130, 120, 121 are
connected in zigzags to the direction where refrigerant flows.
Hence, the contact area, namely resistance, between the vertical
side of the core and the refrigerant, is increased.
[0111] At the center of those three cores 130, 120, 121 is
connected to at least one expansion tube 114 based on the
above-described method, and the sector-shaped cores 130, 120, 121
are expanded to the outside to form surface contact with the
internal circumferential surface of the first tube 108.
[0112] As for one embodiment, the first core 121, the second core
120, and the third core 130 are connected in zigzags inside of the
first tube 108, and one single expansion tube 114 is inserted into
the inside.
[0113] Accordingly, vapor refrigerant passing through the first
tube 121 is heated up and compressed by liquid inside of the second
tube 120, the first core 130, the second core 120, the third core
121, and the expansion tube 114.
[0114] Another embodiment suggests that a variety of shapes and
structures are possible so that at least one sector-shaped core can
be connected to the inside of the first tube to have at least one
tube or no tube at all.
[0115] FIG. 18 illustrates a radial wave shaped core 122 as a
modification of the radial core of FIG. 14.
[0116] As shown in FIG. 18, low-temperature, low-pressure liquid
flowing in a first tube is faced with the wave shaped core and as a
result of this, resistance and fluid vortex are created, whereby
heat conductivity with high-temperature, high-pressure liquid in a
second tube can be increased.
[0117] FIG. 19 illustrates that a core 123 is housed in a second
tube, different from the structure shown in FIG. 14 where a core
130 is housed in a first tube for heat transfer. Whether the core
is in the first tube or second tube, its operational
characteristics are same.
[0118] FIG. 20 is a side cross-sectional view of a liquid-vapor
heat exchanger according to another embodiment of the present
invention, and FIGS. 21 and 22 are exploded perspective view of the
liquid-vapor heat exchanger shown in FIG. 20.
[0119] As shown in FIG. 20, a dual-tube liquid-vapor heat exchanger
102 is provided, a first tube 108 being inside and a second tube
109 being outside. One side of the first tube 108 in the second
tube 109 is connected to the exit 110 of an evaporator and the
other side thereof is connected to the entrance 111 of a
compressor, thereby sucking in low-temperature, low-pressure vapor
and changing heat with liquid flowing in the second tube 109 before
sending it to the compressor.
[0120] As described above, the first tube 108 is connected to the
exit of the evaporator and to the entrance of the compressor, and
the low-temperature, low-pressure vapor refrigerant flows therein.
On the other hand, the second tube 109 outside of the first tube
108 is connected to the exit of a condenser and to the entrance of
an expansion valve. Inside the second tube is mid-temperature,
high-pressure liquid as counter flow or parallel flow of the
refrigerant flowing in the first tube 108 so that the temperature
of the vapor inside the first tube 108 is raised. In this case,
more fluid vortex is created by a spiral inner core 124 with a
plurality of folded surfaces forming line or surface contact with a
certain surface of the internal circumferential surface of the
first tube 108. Thus, working fluid itself collides with the tube
wall and activates heat transfer for more heat exchange.
[0121] The above operation will be explained with reference to
FIGS. 21 and 22.
[0122] To form the spiral shaped core 124 with a plurality of
folded surfaces, a rectangular board is bent, and then installed in
a manner that the core 124 forms line or surface contact with the
internal circumferential surface of the first tube 108. When the
low-temperature refrigerant flows in the first tube 108, it flows
between the internal circumferential surface of the first tube 108
and the outside of the spiral core 124, and is heated up through
heat exchange with mid-temperature refrigerant inside the second
tube 109. This mid-temperature refrigerant collides with the plural
folded surfaces formed on the spiral core 124 and fluid vortex is
created. Through this vortex, the low-temperature refrigerant
inside the first tube 108 is easily mixed with the refrigerant
inside the second tube 109.
[0123] Therefore, the refrigerant inside the first tube 108 quickly
changes to mid-temperature refrigerant within a short period of
time.
[0124] FIG. 23 illustrates a ph diagram.
[0125] As shown in FIG. 23, in a compression cooling cycle,
enthalpy at a compressor {circle over (2)}increases but decreases
at an expansion valve {circle over (1)}and evaporator {circle over
(1)}. On the whole, heating performance is noticeably improved.
[0126] According to the present invention, for more effective heat
exchange and air conditioning/heating the dual-tube heat exchange
is installed at the entrance of the compressor and a means for
switching a cooling cycle is disposed between the outdoor heat
exchanger including the condenser and the indoor heat exchanger
including the evaporator. Therefore, during the air conditioning
operation, since mid-temperature, high-pressure liquid refrigerant
at the exit of the condenser and low-temperature, low-pressure
superheated refrigerant at the exit of the evaporator undergo heat
exchange more effectively. Accordingly, super heating of the liquid
refrigerant at the exit of the condenser is increased, refrigerant
flow characteristics of the expansion unit are improved, and
difference between the enthalpy at the entrance of the evaporator
and the enthalpy at the entrance/exit of the evaporator becomes
great, resulting in the enhanced air conditioning capacity.
[0127] The heat exchanger of the invention is characterized of dual
tubes and improved heating performance, which is realized by
forming line or surface contact between the tube and the core of
the heat exchanger for performing heat exchange by counter flow or
parallel flow.
[0128] Therefore, according to the present invention, increasing
sub cooling of the outdoor heat exchanger increases refrigerant
flow of the expansion unit, improves refrigerant flow
characteristics in dependence of enthalpy difference at the
entrance and exit of the evaporator and thus, enhances the total
efficiency of the system. Increasing super heating at the entrance
of the compressor prevents liquid (or fluid) from entering into the
compressor, prevents temperature increase at the entrance of the
compressor and thus, ensures excellent performance even at high
speed operation.
[0129] Also, by connecting the easy-to-manufacture, sector-shaped
core to the inside of the tube where vapor refrigerant flows,
surface contact is formed between the core and the tube surface and
this in turn improves heating performance of the refrigerant that
is changed to liquid-vapor phase through the surface contact with
the tube surface.
[0130] In addition, the expansion tube is inserted into the center
of the core to ensure that the core is closely adhered to the tube
surface. In so doing, the heating performance by the core expansion
and expansion tube is greatly improved.
[0131] Also, the internal core used to form folded surfaces
activates the generation of vortex. Thus, the working fluid itself
collides with the tube wall more often and heat transfer is
activated.
[0132] While the invention has been shown and described with
reference to certain preferred embodiments thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the invention as defined by the appended claims.
[0133] The foregoing embodiments and advantages are merely
exemplary and are not to be construed as limiting the present
invention. The present teaching can be readily applied to other
types of apparatuses. The description of the present invention is
intended to be illustrative, and not to limit the scope of the
claims. Many alternatives, modifications, and variations will be
apparent to those skilled in the art. In the claims,
means-plus-function clauses are intended to cover the structures
described herein as performing the recited function and not only
structural equivalents but also equivalent structures.
* * * * *