U.S. patent application number 11/249321 was filed with the patent office on 2006-06-08 for cooling/heating system and method for controlling the same.
This patent application is currently assigned to LG Electronics Inc.. Invention is credited to Se Dong Chang, Baik Young Chung, Ju Won Kim, Sai Kee Oh, Bong Soo Park, Chi Woo Song.
Application Number | 20060117778 11/249321 |
Document ID | / |
Family ID | 36036137 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060117778 |
Kind Code |
A1 |
Oh; Sai Kee ; et
al. |
June 8, 2006 |
Cooling/heating system and method for controlling the same
Abstract
A cooling/heating system is disclosed which includes a
compressor, an indoor heat exchanger, an expansion device, and an
outdoor heat exchanger which are connected in series via a
refrigerant line, wherein a refrigerant, which flows through the
refrigerant line, heat-exchanges with supply water. A method for
controlling the cooling/heating system is also disclosed.
Inventors: |
Oh; Sai Kee; (Anyang-si,
KR) ; Park; Bong Soo; (Seoul, KR) ; Song; Chi
Woo; (Incheon-si, KR) ; Kim; Ju Won;
(Changwon-si, KR) ; Chang; Se Dong;
(Gwangmyeong-si, KR) ; Chung; Baik Young;
(Incheon-si, KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
LG Electronics Inc.
|
Family ID: |
36036137 |
Appl. No.: |
11/249321 |
Filed: |
October 14, 2005 |
Current U.S.
Class: |
62/238.7 ;
62/160; 62/324.1 |
Current CPC
Class: |
F25B 29/003 20130101;
F25B 2400/04 20130101; F25B 2339/047 20130101; F25B 27/00
20130101 |
Class at
Publication: |
062/238.7 ;
062/324.1; 062/160 |
International
Class: |
F25B 13/00 20060101
F25B013/00; F25B 27/00 20060101 F25B027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 2, 2004 |
KR |
P2004-100506 |
Claims
1. A cooling/heating system comprising: a compressor, an indoor
heat exchanger, an expansion device, and an outdoor heat exchanger
which are connected in series via a refrigerant line, wherein a
refrigerant, which flows through the refrigerant line,
heat-exchanges with supply water.
2. The cooling/heating system according to claim 1, wherein: the
refrigerant line comprises a first parallel line and a second
parallel line which are arranged between the expansion device and
the compressor; and the outdoor heat exchanger is arranged in the
first parallel line.
3. The cooling/heating system according to claim 2, further
comprising: a first heat exchanger, through which the supply water
passes, and which is arranged in the second parallel line, the
first heat exchanger heat-exchanging with the refrigerant passing
through the second parallel line, using the supply water.
4. The cooling/heating system according to claim 3, further
comprising: a connecting line arranged between predetermined
portions of the first and second parallel lines; and a valve
arranged in the connecting line to open/close a refrigerant flow
path through the connecting line.
5. The cooling/heating system according to claim 2, further
comprising: a second heat exchanger, through which the supply water
passes, and which is arranged in the first parallel line between
the outdoor heat exchanger and the compressor, the second heat
exchanger heat-exchanging with the refrigerant passing through the
first parallel line, using the supply water.
6. The cooling/heating system according to claim 2, further
comprising: a third heat exchanger, through which the supply water
passes, and which is arranged in the refrigerant line between the
compressor and the indoor heat exchanger, the third heat exchanger
heat-exchanging with the refrigerant passing through the
refrigerant line between the compressor and the indoor heat
exchanger, using the supply water.
7. The cooling/heating system according to claim 2, further
comprising: a bypass line connected between a portion of the
refrigerant line arranged between the expansion device and the
indoor heat exchanger and a portion of the refrigerant line
arranged between the compressor and the outdoor heat exchanger.
8. The cooling/heating system according to claim 7, further
comprising: a fourth heat exchanger, through which the supply water
passes, and which is arranged in the bypass line, the fourth heat
exchanger heat-exchanging with the refrigerant passing through the
bypass line, using the supply water.
9. The cooling/heating system according to claim 8, further
comprising: a check valve arranged at a refrigerant inlet side of
the fourth heat exchanger.
10. The cooling/heating system according to claim 3, further
comprising: a second heat exchanger, through which the supply water
passes, and which is arranged in the first parallel line between
the outdoor heat exchanger and the compressor, the second heat
exchanger heat-exchanging with the refrigerant passing through the
first parallel line, using the supply water.
11. The cooling/heating system according to claim 10, further
comprising: a third heat exchanger, through which the supply water
passes, and which is arranged in the refrigerant line between the
compressor and the indoor heat exchanger, the third heat exchanger
heat-exchanging with the refrigerant passing through the
refrigerant line between the compressor and the indoor heat
exchanger, using the supply water.
12. The cooling/heating system according to claim 11, further
comprising: a bypass line connected between a portion of the
refrigerant line arranged between the expansion device and the
indoor heat exchanger and a portion of the refrigerant line
arranged between the compressor and the outdoor heat exchanger.
13. The cooling/heating system according to claim 12, further
comprising: a fourth heat exchanger, through which the supply water
passes, and which is arranged in the bypass line, the fourth heat
exchanger heat-exchanging with the refrigerant passing through the
bypass line, using the supply water.
14. The cooling/heating system according to claim 13, wherein the
first through fourth heat exchangers have independent supply water
flow paths, respectively.
15. The cooling/heating system according to claim 13, wherein at
least two of the first through fourth heat exchangers have a common
supply water flow path.
16. The cooling/heating system according to claim 1, wherein the
refrigerant line comprises a first parallel line and a second
parallel line which are arranged between the expansion device and
the outdoor heat exchanger, further comprising: a first heat
exchanger, through which the supply water passes, and which is
arranged in the second parallel line, the first heat exchanger
heat-exchanging with the refrigerant passing through the second
parallel line, using the supply water.
17. The cooling/heating system according to claim 16, further
comprising: a valve arranged in the second parallel line to
open/close a refrigerant flow path through the connecting line.
18. The cooling/heating system according to claim 17, wherein the
valve is arranged at a refrigerant inlet side of the first heat
exchanger.
19. The cooling/heating system according to claim 16, further
comprising: a second heat exchanger, through which the supply water
passes, and which is arranged in the refrigerant line between the
outdoor heat exchanger and the compressor, the second heat
exchanger heat-exchanging with the refrigerant passing through the
refrigerant line, using the supply water.
20. The cooling/heating system according to claim 16, further
comprising: a third heat exchanger, through which the supply water
passes, and which is arranged in the refrigerant line between the
compressor and the indoor heat exchanger, the third heat exchanger
heat-exchanging with the refrigerant passing through the
refrigerant line between the compressor and the indoor heat
exchanger, using the supply water.
21. The cooling/heating system according to claim 16, further
comprising: a bypass line connected between a portion of the
refrigerant line arranged between the expansion device and the
indoor heat exchanger and a portion of the refrigerant line
arranged between the compressor and the outdoor heat exchanger.
22. The cooling/heating system according to claim 21, further
comprising: a fourth heat exchanger, through which the supply water
passes, and which is arranged in the bypass line, the fourth heat
exchanger heat-exchanging with the refrigerant passing through the
bypass line, using the supply water.
23. The cooling/heating system according to claim 22, further
comprising: a check valve arranged at a refrigerant inlet side of
the fourth heat exchanger.
24. The cooling/heating system according to claim 19, further
comprising: a third heat exchanger, through which the supply water
passes, and which is arranged in the refrigerant line between the
compressor and the indoor heat exchanger, the third heat exchanger
heat-exchanging with the refrigerant passing through the
refrigerant line between the compressor and the indoor heat
exchanger, using the supply water.
25. The cooling/heating system according to claim 24, further
comprising: a bypass line connected between a portion of the
refrigerant line arranged between the expansion device and the
indoor heat exchanger and a portion of the refrigerant line
arranged between the compressor and the outdoor heat exchanger.
26. The cooling/heating system according to claim 25, further
comprising: a fourth heat exchanger, through which the supply water
passes, and which is arranged in the bypass line, the fourth heat
exchanger heat-exchanging with the refrigerant passing through the
bypass line, using the supply water.
27. The cooling/heating system according to claim 26, further
comprising: a temperature sensor arranged at a refrigerant outlet
side of at least one of the first through fourth heat
exchangers.
28. The cooling/heating system according to claim 26, wherein the
first through fourth heat exchangers have independent supply water
flow paths, respectively.
29. The cooling/heating system according to claim 26, wherein at
least two of the first through fourth heat exchangers have a common
supply water flow path.
30. A cooling/heating system comprising: a compressor, an indoor
heat exchanger, an expansion device, and an outdoor heat exchanger
which are connected in series via a refrigerant line; a bypass line
connected between a portion of the refrigerant line arranged
between the expansion device and the indoor heat exchanger and a
portion of the refrigerant line arranged between the compressor and
the outdoor heat exchanger; and a supply water heat exchanger,
through which the supply water passes, and which is arranged in the
bypass line, the supply water heat exchanger heat-exchanging with
the refrigerant passing through the bypass line, using the supply
water.
31. The cooling/heating system according to claim 30, further
comprising: a check valve arranged at a refrigerant inlet side of
the supply water heat exchanger.
32. A method for controlling a cooling/heating system including a
compressor, an indoor heat exchanger, an expansion device, and an
outdoor heat exchanger which are connected in series via a
refrigerant line, a bypass line connected between a portion of the
refrigerant line arranged between the expansion device and the
indoor heat exchanger and a portion of the refrigerant line
arranged between the compressor and the outdoor heat exchanger, and
a supply water heat exchanger arranged in the bypass line, the
method comprising the steps of: determining whether or not a
refrigerant is introduced into the bypass line during a heating
operation of the cooling/heating system; and supplying supply water
to the supply water heat exchanger when it is determined that the
refrigerant is introduced into the bypass line, thereby causing the
supply water to heat-exchange with the refrigerant in the supply
water heat exchanger.
33. A method for controlling a cooling/heating system including a
compressor, an indoor heat exchanger, an expansion device, and an
outdoor heat exchanger which are connected in series via a
refrigerant line, and a supply water heat exchanger arranged in a
predetermined portion of the refrigerant line, the method
comprising the steps of: determining whether or not a refrigerant,
which is introduced into the supply water heat exchanger through
the refrigerant line, has a temperature not more than a
predetermined temperature during a heating operation of the
cooling/heating system; and supplying supply water to the supply
water heat exchanger when it is determined that the refrigerant
temperature is not more than the predetermined temperature, thereby
causing the supply water to heat-exchange with the refrigerant in
the supply water heat exchanger.
34. A method for controlling a cooling/heating system including a
compressor, an indoor heat exchanger, an expansion device, and an
outdoor heat exchanger which are connected in series via a
refrigerant line, first and second parallel lines included in the
refrigerant line and arranged between the expansion device and the
compressor, a connecting line arranged between predetermined
portions of the first and second parallel lines, a valve arranged
in the connecting line to open/close a refrigerant flow path
through the connecting line, and a supply water heat exchanger
arranged in the second parallel line, the outdoor heat exchanger
being arranged in the first parallel line, wherein the valve of the
connecting line is opened during a defrosting operation of the
cooling/heating system so that supply water is supplied to the
supply water heat exchanger via the connecting line and the second
parallel line, to heat-exchange with a refrigerant passing through
the supply water heat exchanger.
35. A method for controlling a cooling/heating system including a
compressor, an indoor heat exchanger, an expansion device, and an
outdoor heat exchanger which are connected in series via a
refrigerant line, first and second parallel lines included in the
refrigerant line and arranged between the expansion device and the
compressor, a valve arranged in the second parallel line to
open/close a refrigerant flow path through the connecting line, and
a supply water heat exchanger arranged in the second parallel line,
the outdoor heat exchanger being arranged in the first parallel
line, wherein the valve of the second parallel line is opened
during a defrosting operation of the cooling/heating system so that
supply water is supplied to the supply water heat exchanger via the
second parallel line, to heat-exchange with a refrigerant passing
through the supply water heat exchanger.
Description
[0001] This application claims the benefit of Korean Patent
Application No. P2004-100506, filed on Dec. 02, 2004, which is
hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a cooling/heating system,
and more particularly, to a cooling/heating system wherein heating
is carried out using hot water supplied from a district heating
net, and a method for controlling the cooling/heating system.
[0004] 2. Discussion of the Related Art
[0005] Generally, air conditioning systems perform procedures of
compressing, condensing, expanding and evaporating a refrigerant to
cool and/or heat a confined space.
[0006] Such air conditioning systems are classified into a general
type wherein one indoor unit is connected to one outdoor unit, and
a multi-unit type wherein a plurality of indoor units are connected
to one outdoor unit. Such air conditioning systems are also
classified into a cooling type wherein a refrigerant flows only in
one direction through a refrigerant cycle, to supply cold air to a
confined space, and a cooling and heating type wherein a
refrigerant flows bi-directionally in a selective manner through a
refrigerant cycle, to selectively supply cold air or hot air to a
confined space.
[0007] Recent tendency of building construction is to densely
construct large buildings in a wide area, as in apartment
complexes. Also, such apartment complexes have been densely
constructed in neighboring areas. In such a dense building area,
hot water is supplied through a central supply system, in order to
conserve energy and for the convenience of living. In such a dense
building area, a district heating system using hot water is also
mainly used to heat buildings.
[0008] In an area using the district heating system, each building
therein must be equipped with both a heating system and a cooling
system. For example, a system for cooling purposes alone, which
uses refrigerant pipes, is installed in each building. Also, an
indoor unit for heating purposes alone, which uses hot water pipes,
is installed in each room of each building. In this arrangement,
hot water from a district heating system is circulated through each
indoor unit in heating mode. On the other hand, in cooling mode,
each cooling system is operated.
[0009] However, the above-mentioned conventional cooling/heating
system has the following problems.
[0010] First, since the conventional district cooling/heating
system must be equipped with indoor units for heating purposes
alone, in addition to the systems for cooling purposes alone, there
are problems of double installation costs and an increase in
maintenance and repair costs caused by the installation of both the
cooling and heating systems.
[0011] Second, since compression of a refrigerant using compressors
and circulation of the refrigerant are required in the
above-mentioned general cooling/heating system, there is a problem
of an increase in power consumption caused by an increase in the
compression work of the compressors.
[0012] Third, in the above-mentioned general cooling/heating
system, frost is formed on outdoor heat exchangers in heating mode.
In order to remove the frost, a defrosting operation is carried out
in which a refrigerant is circulated in cooling mode. For this
reason, there is a problem in that the heating operation cannot be
continuously carried out.
SUMMARY OF THE INVENTION
[0013] Accordingly, the present invention is directed to a
cooling/heating system and a method for controlling the same that
substantially obviate one or more problems due to limitations and
disadvantages of the related art.
[0014] An object of the present invention is to provide a
cooling/heating system and a method for controlling the same, which
are capable of reducing the installation costs, the maintenance and
repair costs, and the consumption of power, while achieving a
continuous heating operation.
[0015] 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 objectives and other
advantages of the invention may be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0016] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, a cooling/heating system comprises: a
compressor, an indoor heat exchanger, an expansion device, and an
outdoor heat exchanger which are connected in series via a
refrigerant line, wherein a refrigerant, which flows through the
refrigerant line, heat-exchanges with supply water.
[0017] The refrigerant line may comprise a first parallel line and
a second parallel line which are arranged between the expansion
device and the compressor. The outdoor heat exchanger may be
arranged in the first parallel line.
[0018] The cooling/heating system may further comprise a first heat
exchanger, through which the supply water passes, and which is
arranged in the second parallel line. The first heat exchanger
heat-exchanges with the refrigerant passing through the second
parallel line, using the supply water.
[0019] The cooling/heating system may further comprise a second
heat exchanger, through which the supply water passes, and which is
arranged in the first parallel line between the outdoor heat
exchanger and the compressor. The second heat exchanger
heat-exchanges with the refrigerant passing through the first
parallel line, using the supply water.
[0020] The cooling/heating system may further comprise a third heat
exchanger, through which the supply water passes, and which is
arranged in the refrigerant line between the compressor and the
indoor heat exchanger. The third heat exchanger heat-exchanges with
the refrigerant passing through the refrigerant line between the
compressor and the indoor heat exchanger, using the supply
water.
[0021] The cooling/heating system may further comprise a bypass
line connected between a portion of the refrigerant line arranged
between the expansion device and the indoor heat exchanger and a
portion of the refrigerant line arranged between the compressor and
the outdoor heat exchanger.
[0022] The cooling/heating system may further comprise a fourth
heat exchanger, through which the supply water passes, and which is
arranged in the bypass line. The fourth heat exchanger
heat-exchanges with the refrigerant passing through the bypass
line, using the supply water.
[0023] The first through fourth heat exchangers may have
independent supply water flow paths, respectively. Alternatively,
at least two of the first through fourth heat exchangers may have a
common supply water flow path.
[0024] The refrigerant line may comprise a first parallel line and
a second parallel line which are arranged between the expansion
device and the outdoor heat exchanger. The cooling/heating system
may further comprise a first heat exchanger, through which the
supply water passes, and which is arranged in the second parallel
line. The first heat exchanger heat-exchanges with the refrigerant
passing through the second parallel line, using the supply
water.
[0025] The cooling/heating system may further comprise a valve
arranged in the second parallel line to open/close a refrigerant
flow path through the connecting line.
[0026] The cooling/heating system may further comprise a second
heat exchanger, through which the supply water passes, and which is
arranged in the refrigerant line between the outdoor heat exchanger
and the compressor. The second heat exchanger heat-exchanges with
the refrigerant passing through the refrigerant line, using the
supply water.
[0027] The cooling/heating system may further comprise a third heat
exchanger, through which the supply water passes, and which is
arranged in the refrigerant line between the compressor and the
indoor heat exchanger. The third heat exchanger heat-exchanges with
the refrigerant passing through the refrigerant line between the
compressor and the indoor heat exchanger, using the supply
water.
[0028] The cooling/heating system may further comprise a bypass
line connected between a portion of the refrigerant line arranged
between the expansion device and the indoor heat exchanger and a
portion of the refrigerant line arranged between the compressor and
the outdoor heat exchanger.
[0029] The cooling/heating system may further comprise a fourth
heat exchanger, through which the supply water passes, and which is
arranged in the bypass line. The fourth heat exchanger
heat-exchanges with the refrigerant passing through the bypass
line, using the supply water.
[0030] The cooling/heating system may further comprise a
temperature sensor arranged at a refrigerant outlet side of at
least one of the first through fourth heat exchangers.
[0031] The first through fourth heat exchangers may have
independent supply water flow paths, respectively. Alternatively,
at least two of the first through fourth heat exchangers may have a
common supply water flow path.
[0032] In another aspect of the present invention, a
cooling/heating system comprises: a compressor, an indoor heat
exchanger, an expansion device, and an outdoor heat exchanger which
are connected in series via a refrigerant line; a bypass line
connected between a portion of the refrigerant line arranged
between the expansion device and the indoor heat exchanger and a
portion of the refrigerant line arranged between the compressor and
the outdoor heat exchanger; and a supply water heat exchanger,
through which the supply water passes, and which is arranged in the
bypass line, the supply water heat exchanger heat-exchanging with
the refrigerant passing through the bypass line, using the supply
water.
[0033] In another aspect of the present invention, a method for
controlling a cooling/heating system including a compressor, an
indoor heat exchanger, an expansion device, and an outdoor heat
exchanger which are connected in series via a refrigerant line, a
bypass line connected between a portion of the refrigerant line
arranged between the expansion device and the indoor heat exchanger
and a portion of the refrigerant line arranged between the
compressor and the outdoor heat exchanger, and a supply water heat
exchanger arranged in the bypass line, comprises the steps of:
determining whether or not a refrigerant is introduced into the
bypass line during a heating operation of the cooling/heating
system; and supplying supply water to the supply water heat
exchanger when it is determined that the refrigerant is introduced
into the bypass line, thereby causing the supply water to
heat-exchange with the refrigerant in the supply water heat
exchanger.
[0034] In another aspect of the present invention, a method for
controlling a cooling/heating system including a compressor, an
indoor heat exchanger, an expansion device, and an outdoor heat
exchanger which are connected in series via a refrigerant line, and
a supply water heat exchanger arranged in a predetermined portion
of the refrigerant line, comprises the steps of: determining
whether or not a refrigerant, which is introduced into the supply
water heat exchanger through the refrigerant line, has a
temperature not more than a predetermined temperature during a
heating operation of the cooling/heating system; and supplying
supply water to the supply water heat exchanger when it is
determined that the refrigerant temperature is not more than the
predetermined temperature, thereby causing the supply water to
heat-exchange with the refrigerant in the supply water heat
exchanger.
[0035] In another aspect of the present invention, a method for
controlling a cooling/heating system including a compressor, an
indoor heat exchanger, an expansion device, and an outdoor heat
exchanger which are connected in series via a refrigerant line,
first and second parallel lines included in the refrigerant line
and arranged between the expansion device and the compressor, a
connecting line arranged between predetermined portions of the
first and second parallel lines, a valve arranged in the connecting
line to open/close a refrigerant flow path through the connecting
line, and a supply water heat exchanger arranged in the second
parallel line, the outdoor heat exchanger being arranged in the
first parallel line, is characterized in that the valve of the
connecting line is opened during a defrosting operation of the
cooling/heating system so that supply water is supplied to the
supply water heat exchanger via the connecting line and the second
parallel line, to heat-exchange with a refrigerant passing through
the supply water heat exchanger.
[0036] In another aspect of the present invention, a method for
controlling a cooling/heating system including a compressor, an
indoor heat exchanger, an expansion device, and an outdoor heat
exchanger which are connected in series via a refrigerant line,
first and second parallel lines included in the refrigerant line
and arranged between the expansion device and the compressor, a
valve arranged in the second parallel line to open/close a
refrigerant flow path through the connecting line, and a supply
water heat exchanger arranged in the second parallel line, the
outdoor heat exchanger being arranged in the first parallel line,
is characterized in that the valve of the second parallel line is
opened during a defrosting operation of the cooling/heating system
so that supply water is supplied to the supply water heat exchanger
via the second parallel line, to heat-exchange with a refrigerant
passing through the supply water heat exchanger.
[0037] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0039] FIG. 1A is a block diagram illustrating a cooling/heating
system according to a first embodiment of the present
invention;
[0040] FIG. 1B is a block diagram illustrating a modified example
of the cooling/heating system shown in FIG. 1A;
[0041] FIG. 2A is a block diagram illustrating a cooling/heating
system according to a second embodiment of the present
invention;
[0042] FIG. 2B is a block diagram illustrating a modified example
of the cooling/heating system shown in FIG. 2A;
[0043] FIG. 2C is a block diagram illustrating operation of the
cooling/heating system shown in FIG. 2A;
[0044] FIG. 3A is a block diagram illustrating a cooling/heating
system according to a third embodiment of the present
invention;
[0045] FIG. 3B is a block diagram illustrating a modified example
of the cooling/heating system shown in FIG. 3A;
[0046] FIG. 4A is a block diagram illustrating a cooling/heating
system according to a fourth embodiment of the present
invention;
[0047] FIG. 4B is a block diagram illustrating a modified example
of the cooling/heating system shown in FIG. 4A; and
[0048] FIG. 4C is a block diagram illustrating operation of the
cooling/heating system shown in FIG. 4A.
DETAILED DESCRIPTION OF THE INVENTION
[0049] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0050] Hereinafter, a cooling/heating system according to a first
embodiment of the present invention will be described with
reference to FIG. 1A.
[0051] This cooling/heating system includes a compressor 111, an
indoor heat exchanger 112, an expansion device 113, and an outdoor
heat exchanger 114 which are connected in series via refrigerant
lines, in this order, to heat exchange a refrigerant flowing
through the refrigerant lines with supply water. The supply water
means supply water for district heating purposes supplied from an
external source such as a cogeneration system or cogeneration power
plant. Since such supply water is typically supplied in a hot
state, it will be referred to as "hot water" hereinafter.
[0052] The hot water is maintained at a temperature of about 70 to
90.degree. C. when reaching a building to which the hot water is to
be supplied. Thus, such hot water can be effectively applied to a
refrigerant cycle.
[0053] The refrigerant line arranged between the expansion device
113 and the compressor 111 includes a pair of parallel lines,
namely, first and second parallel lines 121 and 122. The outdoor
heat exchanger 114 is arranged in the first parallel line 121.
[0054] Preferably, a first heat exchanger 131 is arranged in the
second parallel line 122, to heat-exchange with the refrigerant.
Since the first heat exchanger 131 heat-exchanges with the
refrigerant using hot water in this case, the first heat exchanger
131 practically functions as a heater. In heating mode, the first
heat exchanger 131 heats the refrigerant, which has been expanded
by the expansion device 113, to a gas state, so that the gas
refrigerant is introduced into the compressor 111 via the second
parallel line 122.
[0055] Preferably, a connecting line 123 is arranged between
predetermined portions of the first and second parallel lines 121
and 122. Preferably, a valve 135 is also arranged in the connecting
line 123, to open/close a refrigerant flow path through the
connecting line 123. For the connecting line valve 135, an ON/OFF
valve may be used which can simply open/close the refrigerant flow
path. Of course, a solenoid valve may be used which can adjust the
opening degree of the refrigerant flow path. Also, the connecting
line valve 135 may be arranged at a region where the connecting
line 123 and the second parallel line 122 are connected. In this
case, for the connecting line valve 135, a three-way valve may be
used which selectively switches the refrigerant emerging from the
first heat exchanger 131 between the connecting line 123 and the
second parallel line 122.
[0056] Also, it is preferred that a second heat exchanger 132 be
arranged in the first parallel line 121 between the outdoor heat
exchanger 114 and the compressor 111, to heat-exchange with the
refrigerant. Since the second heat exchanger 132 heat-exchanges
with the refrigerant using hot water in this case, the third heat
exchanger 133 practically functions as a heater. It is also
preferred that a third heat exchanger 133 be arranged in a
refrigerant line 124 arranged between the compressor 111 and the
indoor heat exchanger 112, to heat-exchange with the refrigerant.
Since the third heat exchanger 133 heat-exchanges with the
refrigerant using hot water in this case, the third heat exchanger
133 practically functions as a heater.
[0057] Also, preferably, temperature sensors 131a, 132a, and 133a
are arranged at respective refrigerant outlet sides of the first,
second, and third heat exchangers 131, 132, and 133. Alternatively,
such a temperature sensor may be arranged at any one or two of the
first, second, and third heat exchangers 131, 132, and 133. For
example, one temperature sensor may be arranged at the first heat
exchanger 131, the second heat exchanger 132, or the third heat
exchanger 133. Alternatively, two temperature sensors may be
arranged at the first and second heat exchangers 131 and 132, the
second and third heat exchangers 132 and 133, or the first and
third heat exchangers 131 and 133, respectively.
[0058] Each of the first, second, and third heat exchangers 131,
132, and 133 may include heat transfer fins formed around the
refrigerant line passing through the associated heat exchanger, and
a hot water line arranged to heat-exchange with the refrigerant
line formed with the heat transfer fins. The hot water line may
form a double pipe structure, together with the associated
refrigerant line. In this structure, the flow directions of the
refrigerant and hot water may be identical or opposite to each
other. In terms of heat exchange efficiency, it is preferred that
the flow directions of the refrigerant and hot water be opposite to
each other. The heat exchangers may have various structures other
than the above-described structure, so long as the refrigerant can
come into thermal contact with the hot water.
[0059] The hot water lines of the first, second, and third heat
exchangers 131, 132, and 133 are independent to provide independent
hot water flow paths for the heat exchangers, respectively, as
shown in FIG. 1A. Valves 131b, 132b, and 133b are arranged in the
hot water lines, respectively. Accordingly, when the temperature of
the refrigerant, which passes through any one of the heat
exchangers 131, 132, and 133, is lower than the temperature of the
hot water by a predetermined value or more, the hot water may be
supplied to the associated heat exchanger. If not, the supply of
the hot water may be cut off.
[0060] It will also be appreciated that the hot water lines of at
least two of the first, second, and third heat exchangers 131, 132,
and 133 may be connected together in the form of a common hot water
line to provide a common hot water flow path, as shown in FIG. 1B.
In this case, it is preferred that the common hot water line first
pass through the heat exchanger which is preferentially required to
heat the refrigerant in the heating mode. For example, the common
hot water line first passes through the third heat exchanger
133.
[0061] Operation of the above-described cooling/heating system will
now be described with reference to FIG. 1A.
[0062] When the heating operation of the system is initiated, the
refrigerant flows in a dotted-line direction shown in FIG. 1A.
[0063] That is, the refrigerant is introduced into the third heat
exchanger 133 after being compressed by the compressor 111. At this
time, introduction of the hot water is carried out only when it is
determined that the temperature of the refrigerant is outside a
predetermined temperature range set in a controller (not shown).
The introduced hot water increases the temperature of the
refrigerant when the temperature of the refrigerant is low, and
decreases the temperature of the refrigerant when the temperature
of the refrigerant is high. Thus, the refrigerant discharged from
the compressor 111 can be maintained in the predetermined
temperature range.
[0064] The refrigerant emerging from the third heat exchanger 133
is introduced into the indoor heat exchanger 112 which, in turn,
condenses the introduced refrigerant. At this time, the indoor heat
exchanger 112 heat-exchanges with air present in a confined space,
for example, a room, to be air-conditioned, thereby heating the
room.
[0065] The refrigerant emerging from the indoor heat exchanger 112
is then introduced into the second parallel line 122 after being
expanded by the expansion device 113. The refrigerant introduced
into the second parallel line 122 is heated while passing through
the first heat exchanger 131, so that the refrigerant is changed
from a two-phase state to a gas phase. The refrigerant emerging
from the second parallel line 122 is introduced again into the
compressor 111. Since the refrigerant introduced into the
compressor 111 is a gas refrigerant maintained at a temperature
higher than that of the expanded refrigerant, the compression work
of the compressor 111 is reduced.
[0066] While the above-described heating operation is continued for
a predetermined time, the outdoor heat exchanger 114 is exposed to
ambient air. For this reason, frost may be formed on the surface of
the outdoor heat exchanger 114 when ambient temperature is very low
(about -15.degree. C. or below). In this case, accordingly, a
defrosting operation must be carried out to remove the frost.
[0067] When the defrosting operation is initiated, the refrigerant
flows in a solid-line direction shown in FIG. 1A.
[0068] That is, the controller controls the connecting line valve
135 to be opened. As a result, the expanded refrigerant introduced
into the second parallel line 122 is branched into the connecting
line 123 and the second parallel line 122 after heat-exchanging
with the hot water in the first heat exchanger 131. The fraction of
the expanded refrigerant introduced into the connecting line 123
melts the frost formed on the outdoor heat exchanger 114 while
passing through the outdoor heat exchanger 114, and then enters the
compressor 111 after being heated in the second heat exchanger 132.
Also, the remaining fraction of the expanded refrigerant is
introduced into the compressor 111 via the second parallel line
122. Thus, the temperature of the refrigerant supplied to the
compressor 111 is relatively high, so that the compression work of
the compressor 111 can be reduced. Also, since the defrosting
operation is carried out during the heating operation, the heating
operation can be continuously carried out.
[0069] On the other hand, although not shown, the refrigerant
compressed in the compressor 111 is introduced into the first
parallel line 121 in cooling mode. In this case, the refrigerant
from the first parallel line 121 is then introduced into the
expansion device 113 after sequentially passing through the second
heat exchanger 132 and outdoor heat exchanger 114. The refrigerant
expanded by the expansion device 113 is introduced into the
compressor 111 after sequentially passing through the indoor heat
exchanger 112 and third heat exchanger 133.
[0070] Hereinafter, a cooling/heating system according to a second
embodiment of the present invention will be described with
reference to FIG. 2A.
[0071] The second embodiment is different from the first embodiment
in that the cooling/heating system further includes a bypass
line.
[0072] This cooling/heating system includes a compressor 111, an
indoor heat exchanger 112, an expansion device 113, and an outdoor
heat exchanger 114 which are connected in series via refrigerant
lines, in this order. The refrigerant line arranged between the
expansion device 113 and the compressor 111 includes a first
parallel line 121 and a second parallel line 122. The outdoor heat
exchanger 114 is arranged in the first parallel line 121. A first
heat exchanger 131 is arranged in the second parallel line 122. A
connecting line 123 is also arranged to connect the first and
second parallel lines 121 and 122. A valve 135 is also arranged in
the connecting line 123. A second heat exchanger 132 is arranged in
the first parallel line 121 between the outdoor heat exchanger 114
and the compressor 111. Also, a third heat exchanger 133 is
arranged in a refrigerant line 124 arranged between the compressor
111 and the indoor heat exchanger 112. Temperature sensors 131a,
132a, and 133a are arranged at respective refrigerant outlet sides
of the first, second, and third heat exchangers 131, 132, and 133.
The above-described constituent elements are substantially
identical to those of the first embodiment, and, accordingly, no
detailed description thereof will be given.
[0073] A bypass line 141 is connected to the refrigerant line 125
between the expansion device 113 and the indoor heat exchanger 112,
and to the refrigerant line between the compressor 111 and the
outdoor heat exchanger 114. Preferably, a fourth heat exchanger 134
is arranged in the bypass line 141, to heat-exchange with the
refrigerant. In this case, the fourth heat exchanger 134 heats the
refrigerant bypassed through the bypass line 141 using hot water,
so as to enable a gas-phase refrigerant to be introduced into the
compressor 111.
[0074] Preferably, a check valve 142 is arranged in the bypass line
141. The check valve 142 is opened when the pressure of the
refrigerant is not lower than a predetermined pressure. Where the
compressor 111 compresses the refrigerant through two stages, the
check valve 142 is opened in response to the pressure of the
primarily compressed refrigerant. In this state, accordingly, a
fraction of the primarily compressed refrigerant is introduced into
the compressor 111 via the bypass line 141. The refrigerant
introduced into the compressor 111 is then secondarily compressed
by the compressor 111. When the refrigerant is double-compressed in
such a manner, a remarkable increase in compression efficiency is
achieved.
[0075] It is more preferred that the check valve 142 be arranged at
the refrigerant inlet side of the fourth heat exchanger 134. Of
course, the check valve 142 may be arranged at the refrigerant
outlet side of the fourth heat exchanger 134. However, where the
check valve 142 is arranged at the refrigerant outlet side of the
fourth heat exchanger 134, the refrigerant may be unnecessarily
accumulated in the fourth heat exchanger 134, thereby causing a
refrigerant shortage. In order to fundamentally eliminate such
refrigerant shortage phenomenon, it is preferred that the check
valve 142 be arranged at the refrigerant inlet side of the check
valve 142.
[0076] Also, it is preferred that a temperature sensor 134a be
arranged at the refrigerant outlet side of the fourth heat
exchanger 134. The temperature sensor 134a determines the
temperature of the refrigerant discharged from the fourth heat
exchanger 134, and controls the amount of hot water supplied to the
fourth heat exchanger 134, based on the determined discharge
temperature of the refrigerant. For example, when the temperature
of the refrigerant is low, the temperature sensor 134a performs a
control operation to supply a relatively large amount of hot water
to the fourth heat exchanger 134.
[0077] The first, second, third, and fourth heat exchangers 131,
132, 133, and 141 include independent hot water lines to provide
independent hot water flow paths for the heat exchangers,
respectively, as shown in FIG. 2A. Valves 131b, 132b, 133b, and
134b are arranged in the hot water lines, respectively.
Accordingly, when the temperature of the refrigerant, which passes
through any one of the heat exchangers 131, 132, 133, and 134, is
lower than the temperature of the hot water by a predetermined
value or more, the hot water is supplied to the associated heat
exchanger. If not, the supply of the hot water is cut off.
[0078] It will also be appreciated that the hot water lines of at
least two of the first, second, third, and fourth heat exchangers
131, 132, 133, and 134 may be connected together in the form of a
common hot water line to provide a common hot water flow path, as
shown in FIG. 2B. In this case, it is preferred that the common hot
water line first pass through the heat exchanger which is
preferentially required to heat the refrigerant in the heating
mode.
[0079] Operation of the above-described cooling/heating system
according to the second embodiment will now be described. The
operation of the second embodiment is substantially identical to
the operation described in conjunction with the first embodiment.
That is, the refrigerant flows in a dotted-line direction shown in
FIG. 2A in the heating mode of the cooling/heating system, and
flows in a solid-line direction shown in FIG. 2A in the defrosting
mode of the cooling/heating system. Provided, where the compressor
111 compresses the refrigerant through two stages in the heating
mode, a fraction of the refrigerant primarily compressed by the
compressor 111 is introduced into the bypass line 141, so that the
introduced refrigerant applies a certain pressure to the check
valve 142, as shown in FIG. 2C. As the check valve 142 is opened by
the refrigerant pressure, a fraction of the refrigerant primarily
compressed by the compressor 111 is introduced into the fourth heat
exchanger 134 via the bypass line 141. In the fourth heat exchanger
134, the introduced refrigerant heat-exchanges with hot water, so
that the refrigerant is changed to a gas state. The gas refrigerant
is introduced again into the compressor 111 which, in turn,
secondarily compresses the refrigerant. Thus, the refrigerant
compressed through two stages flows throughout the system.
[0080] Hereinafter, a method for controlling the above-described
cooling/heating system will be described.
[0081] When it is determined in the heating mode that hot water is
to be introduced into the fourth heat exchanger 134, the controller
(not shown) performs a control operation to supply hot water to the
fourth heat exchanger 134.
[0082] Also, when it is determined in the heating mode that the
temperature of any one of the first through fourth heat exchangers
is not more than a predetermined temperature set in the controller,
the controller performs a control operation to supply hot water to
the associated heat exchanger. The predetermined temperature of
each heat exchanger must be appropriately set, taking into
consideration the heating capacity and cooling capacity of the
system.
[0083] Now, a cooling/heating system according to a third
embodiment of the present invention will be described with
reference to FIG. 3A.
[0084] This cooling/heating system includes a compressor 161, an
indoor heat exchanger 162, an expansion device 163, and an outdoor
heat exchanger 164 which are connected in series via refrigerant
lines, in this order, to heat exchange a refrigerant flowing
through the refrigerant lines with supply water in heating
mode.
[0085] The refrigerant line arranged between the expansion device
163 and the outdoor heat exchanger 164 includes a first parallel
line 171 and a second parallel line 172. A first heat exchanger 181
is arranged in the second parallel line 172, to heat-exchange with
the refrigerant. Since the first heat exchanger 181 heat-exchanges
with the refrigerant using hot water in this case, the first heat
exchanger 181 practically functions as a heater. A valve 185 is
arranged in the second parallel line 172, to control a refrigerant
flow path through the second parallel line 172. For the valve 185,
an ON/OFF valve may be used which can simply open/close the
refrigerant flow path. Of course, a solenoid valve may be used
which can adjust the opening degree of the refrigerant flow path.
Also, the valve 185 may be arranged at a region where the first and
second parallel lines 171 and 172 are connected. In this case, for
the valve 185, a three-way valve may be used which selectively
switches the refrigerant emerging from the expansion device 163
between the first parallel line 171 and the second parallel line
172.
[0086] It is preferred that a second heat exchanger 182 be arranged
in the refrigerant line 171 between the outdoor heat exchanger 164
and the compressor 161, to heat-exchange with the refrigerant.
Since the second heat exchanger 182 heat-exchanges with the
refrigerant using hot water in this case, the second heat exchanger
182 practically functions as a heater. It is also preferred that a
third heat exchanger 183 be arranged in a refrigerant line 174
arranged between the compressor 161 and the indoor heat exchanger
162, to heat-exchange with the refrigerant. Since the third heat
exchanger 183 heat-exchanges with the refrigerant using hot water
in this case, the third heat exchanger 183 practically functions as
a heater.
[0087] Also, preferably, temperature sensors 181a, 182a, and 183a
are arranged at respective refrigerant outlet sides of the first,
second, and third heat exchangers 181, 182, and 183. Alternatively,
such a temperature sensor may be arranged at any one or two of the
first, second, and third heat exchangers 181, 182, and 183. For
example, one temperature sensor may be arranged at the first heat
exchanger 181, the second heat exchanger 182, or the third heat
exchanger 183. Alternatively, two temperature sensors may be
arranged at the first and second heat exchangers 181 and 182, the
second and third heat exchangers 182 and 183, or the first and
third heat exchangers 181 and 183, respectively.
[0088] Each of the first, second, and third heat exchangers 181,
182, and 183 may include heat transfer fins formed around the
refrigerant line passing through the associated heat exchanger, and
a hot water line arranged to heat-exchange with the refrigerant
line formed with the heat transfer fins. The hot water line may
form a double pipe structure, together with the associated
refrigerant line. In this structure, the flow directions of the
refrigerant and hot water may be identical or opposite to each
other. In terms of heat exchange efficiency, it is preferred that
the flow directions of the refrigerant and hot water be opposite to
each other. The heat exchangers may have various structures other
than the above-described structure, so long as the refrigerant can
come into thermal contact with the hot water.
[0089] As shown in FIG. 3A, the hot water lines of the first,
second, and third heat exchangers 181, 182, and 183 are independent
to provide independent hot water flow paths for the heat
exchangers, respectively. Valves 181b, 182b, and 183b are arranged
in the hot water lines, respectively. Accordingly, when the
temperature of the refrigerant, which passes through any one of the
heat exchangers 181, 182, and 183, is lower than the temperature of
the hot water by a predetermined value or more, the hot water may
be supplied to the associated heat exchanger. If not, the supply of
the hot water may be cut off.
[0090] It will also be appreciated that the hot water lines of at
least two of the first, second, and third heat exchangers 181, 182,
and 183 may be connected together in the form of a common hot water
line to provide a common hot water flow path, as shown in FIG. 3B.
In this case, it is preferred that the common hot water line first
pass through the heat exchanger which is preferentially required to
heat the refrigerant in the heating mode.
[0091] Operation of the above-described cooling/heating system will
now be described.
[0092] When the heating operation of the system is initiated, the
refrigerant flows in a dotted-line direction shown in FIG. 3A.
[0093] That is, the refrigerant is introduced into the third heat
exchanger 183 after being compressed by the compressor 161. At this
time, introduction of the hot water is carried out only when it is
determined that the temperature of the refrigerant is outside a
predetermined temperature range set in a controller (not shown).
The introduced hot water increases the temperature of the
refrigerant when the temperature of the refrigerant is low, and
decreases the temperature of the refrigerant when the temperature
of the refrigerant is high. Thus, the refrigerant discharged from
the compressor 161 can be maintained in the predetermined
temperature range.
[0094] The refrigerant emerging from the third heat exchanger 183
is introduced into the indoor heat exchanger 162 which, in turn,
condenses the introduced refrigerant. At this time, the indoor heat
exchanger 162 heat-exchanges with air present in a room to be
air-conditioned, thereby heating the room.
[0095] The refrigerant emerging from the indoor heat exchanger 162
is then introduced into the first parallel line 171 after being
expanded by the expansion device 163. The refrigerant introduced
into the first parallel line 171 heat-exchanges with ambient air
while passing through the outdoor heat exchanger 164. Subsequently,
the refrigerant is heated while passing through the second heat
exchanger 182, so that the refrigerant is changed from a two-phase
state to a gas phase. The refrigerant is introduced again into the
compressor 161. Since the refrigerant introduced into the
compressor 161 is a gas refrigerant maintained at a temperature
higher than that of the expanded refrigerant, the compression work
of the compressor 161 is reduced.
[0096] While the above-described heating operation is continued for
a predetermined time, the outdoor heat exchanger 164 is exposed to
ambient air. For this reason, when ambient temperature is very low
(about -15.degree. C. or below), frost may be formed on the surface
of the outdoor heat exchanger 164 because the low-temperature
refrigerant is continuously introduced into the outdoor heat
exchanger 164. In this case, accordingly, a defrosting operation
must be carried out to remove the frost.
[0097] When the defrosting operation is initiated, the refrigerant
flows in a solid-line direction shown in FIG. 3A.
[0098] That is, the controller controls the valve 185 of the second
parallel line 172 to be opened. As a result, the expanded
refrigerant is introduced into the second parallel line 172.
Subsequently, the expanded refrigerant enters the outdoor heat
exchanger 164 after heat-exchanging with hot water in the first
heat exchanger 181. The expanded refrigerant melts the frost formed
on the outdoor heat exchanger 164 while passing through the outdoor
heat exchanger 164, and then enters the second heat exchanger 182.
Simultaneously, the expanded refrigerant passing through the first
parallel line 171 is introduced into the second heat exchanger 182
via the outdoor heat exchanger 164. The expanded refrigerant then
enters the compressor 161 after being heated in the second heat
exchanger 182. Thus, the temperature of the refrigerant supplied to
the compressor 161 is relatively high, so that the compression work
of the compressor 161 can be reduced.
[0099] On the other hand, in cooling mode, the refrigerant
compressed in the compressor 161 sequentially passes through the
second heat exchanger 182, outdoor heat exchanger 164, expansion
device 163, indoor heat exchanger 162, and third heat exchanger
183, in this order, and then re-enters the compressor 161.
[0100] Hereinafter, a cooling/heating system according to a fourth
embodiment of the present invention will be described with
reference to FIG. 4A.
[0101] The fourth embodiment is different from the third embodiment
in that the cooling/heating system further includes a bypass
line.
[0102] This cooling/heating system includes a compressor 161, an
indoor heat exchanger 162, an expansion device 163, and an outdoor
heat exchanger 164 which are connected in series via refrigerant
lines, in this order. The refrigerant line arranged between the
expansion device 163 and the outdoor heat exchanger 164 includes a
first parallel line 171 and a second parallel line 172. A first
heat exchanger 181 is arranged in the second parallel line 172. A
valve 185 is arranged in the second parallel line 172. A second
heat exchanger 182 is arranged in the first parallel line 171
between the outdoor heat exchanger 164 and the compressor 161.
Also, a third heat exchanger 183 is arranged in a refrigerant line
174 arranged between the compressor 161 and the indoor heat
exchanger 162. Temperature sensors 181a, 182a, and 183a are
arranged at respective refrigerant outlet sides of the first,
second, and third heat exchangers 181, 182, and 183. Valves 181b,
182b, and 183b are also arranged in the first, second, and third
heat exchangers 181, 182, and 183, respectively. The
above-described constituent elements are substantially identical to
those of the third embodiment, and, accordingly, no detailed
description thereof will be given.
[0103] A bypass line 191 is connected to the refrigerant line 175
between the expansion device 163 and the indoor heat exchanger 162,
and to the refrigerant line between the compressor 161 and the
outdoor heat exchanger 164. Preferably, a fourth heat exchanger 184
is arranged in the bypass line 191, to heat-exchange with the
refrigerant. Since the fourth heat exchanger 184 heat-exchanges
with the refrigerant using hot water in this case, the fourth heat
exchanger 184 practically functions as a heater. In this case, the
fourth heat exchanger 184 heats the refrigerant bypassed through
the bypass line 191, so as to enable a gas-phase refrigerant to be
introduced into the compressor 161.
[0104] Preferably, a check valve 192 is arranged in the bypass line
191. The check valve 192 is opened when the pressure of the
refrigerant is not lower than a predetermined pressure. Where the
compressor 161 compresses the refrigerant through two stages, the
check valve 192 is opened in response to the pressure of the
primarily compressed refrigerant. In this state, accordingly, a
fraction of the primarily compressed refrigerant is introduced into
the compressor 161 via the bypass line 191. The refrigerant
introduced into the compressor 161 is then secondarily compressed
by the compressor 161. When the refrigerant is double-compressed in
such a manner, a remarkable increase in compression efficiency is
achieved.
[0105] It is more preferred that the check valve 192 be arranged at
the refrigerant inlet side of the fourth heat exchanger 184. Of
course, the check valve 192 may be arranged at the refrigerant
outlet side of the fourth heat exchanger 184. However, where the
check valve 192 is arranged at the refrigerant outlet side of the
fourth heat exchanger 184, the refrigerant may be unnecessarily
accumulated in the fourth heat exchanger 184, thereby causing a
refrigerant shortage. In order to fundamentally eliminate such
refrigerant shortage phenomenon, it is preferred that the check
valve 192 be arranged at the refrigerant inlet side of the check
valve 192.
[0106] Also, it is preferred that a temperature sensor 184a be
arranged at the refrigerant outlet side of the fourth heat
exchanger 184. The temperature sensor 184a determines the
temperature of the refrigerant discharged from the fourth heat
exchanger 184, and controls the amount of hot water supplied to the
fourth heat exchanger 184, based on the determined discharge
temperature of the refrigerant. For example, when the temperature
of the refrigerant is low, the temperature sensor 184a performs a
control operation to supply a relatively large amount of hot water
to the fourth heat exchanger 184.
[0107] The first, second, and third heat exchangers 181, 182, and
183 include independent hot water lines to provide independent hot
water flow paths, respectively, as shown in FIG. 4A. In this case,
the valves 181b, 182b, and 183b are arranged in the hot water
lines, respectively. Accordingly, when the temperature of the
refrigerant, which passes through any one of the heat exchangers
181, 182, and 183, is lower than the temperature of the hot water
by a predetermined value or more, the hot water is supplied to the
associated heat exchanger. If not, the supply of the hot water is
cut off.
[0108] It will also be appreciated that the hot water lines of at
least two of the first, second, and third heat exchangers 181, 182,
and 183 may be connected together in the form of a common hot water
line to provide a common hot water flow path, as shown in FIG. 4B.
In this case, it is preferred that the common hot water line first
pass through the heat exchanger which is preferentially required to
heat the refrigerant in the heating mode.
[0109] Operation of the above-described cooling/heating system
according to the fourth embodiment will now be described. The
operation of the fourth embodiment is substantially identical to
the operation described in conjunction with the third embodiment.
That is, the refrigerant flows in a dotted-line direction shown in
FIG. 4A in the heating mode of the cooling/heating system, and
flows in a solid-line direction shown in FIG. 4A in the defrosting
mode of the cooling/heating system. Provided, where the compressor
161 compresses the refrigerant through two stages in the heating
mode, a fraction of the refrigerant primarily compressed by the
compressor 161 is introduced into the bypass line 191, so that the
introduced refrigerant applies a certain pressure to the check
valve 192. As the check valve 192 is opened by the refrigerant
pressure, a fraction of the refrigerant primarily compressed by the
compressor 161 is introduced into the fourth heat exchanger 184 via
the bypass line 191, as shown in FIG. 4C. In the fourth heat
exchanger 184, the introduced refrigerant heat-exchanges with hot
water, so that the refrigerant is changed to a gas state. The gas
refrigerant is introduced again into the compressor 161 which, in
turn, secondarily compresses the refrigerant. Thus, the refrigerant
compressed through two stages flows throughout the system.
[0110] Hereinafter, a method for controlling the above-described
cooling/heating system will be described.
[0111] When it is determined in the heating mode that hot water is
to be introduced into the fourth heat exchanger 184, the controller
(not shown) performs a control operation to supply hot water to the
fourth heat exchanger 184.
[0112] Also, when it is determined in the heating mode that the
temperature of any one of the first through fourth heat exchangers
is not more than a predetermined temperature set in the controller,
the controller performs a control operation to supply hot water to
the associated heat exchanger. The predetermined temperature of
each heat exchanger must be appropriately set, taking into
consideration the heating capacity and cooling capacity of the
system.
[0113] The above-described cooling/heating system according to the
present invention provides the following effects.
[0114] First, in accordance with the present invention, it is
unnecessary to additionally use an indoor unit for heating purposes
using hot water. Accordingly, the maintenance and repair costs are
reduced.
[0115] Second, since the refrigerant is introduced into the
compressor after being heated by hot water in accordance with the
present invention, it is possible to reduce the compression work of
the compressor, and to reduce power consumption.
[0116] Third, since the defrosting operation is carried out
simultaneously with the heating operation in accordance with the
present invention, it is possible to implement a continuous heating
operation.
[0117] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the inventions. Thus,
it is intended that the present invention covers the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *