U.S. patent application number 17/181541 was filed with the patent office on 2021-06-17 for air conditioner.
The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Yusuke ADACHI, Yasuhide HAYAMARU, Komei NAKAJIMA, Masakazu SATO, Yusuke TASHIRO.
Application Number | 20210180842 17/181541 |
Document ID | / |
Family ID | 1000005421470 |
Filed Date | 2021-06-17 |
United States Patent
Application |
20210180842 |
Kind Code |
A1 |
TASHIRO; Yusuke ; et
al. |
June 17, 2021 |
AIR CONDITIONER
Abstract
An air conditioner (10) includes a refrigerant circuit (13) and
refrigerant. The refrigerant circuit (13) has a compressor (1), a
condenser (2), a pressure-regulating valve (3), and an evaporator
(4). The refrigerant is R32. The pressure-regulating valve (3)
includes a flow path (33) causing the refrigerant flowing from the
condenser (2) to flow to the evaporator (4), a pressure reference
chamber (S2) partitioned from the flow path (33) and filled with
inert gas, and a valve portion (34) disposed in the flow path (33).
The pressure-regulating valve (3) is configured to adjust a degree
of opening of the valve portion (34) to adjust a flow rate of the
refrigerant flowing through the flow path (33). The valve portion
(34) is configured to increase the degree of opening when a
pressure in the flow path (33) is higher than a pressure in the
pressure reference chamber (S2), and reduce the degree of opening
when the pressure in the flow path (33) is lower than the pressure
in the pressure reference chamber (S2).
Inventors: |
TASHIRO; Yusuke; (Tokyo,
JP) ; NAKAJIMA; Komei; (Tokyo, JP) ; SATO;
Masakazu; (Tokyo, JP) ; ADACHI; Yusuke;
(Tokyo, JP) ; HAYAMARU; Yasuhide; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
1000005421470 |
Appl. No.: |
17/181541 |
Filed: |
February 22, 2021 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
16313671 |
Dec 27, 2018 |
|
|
|
PCT/JP2016/082119 |
Oct 28, 2016 |
|
|
|
17181541 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 13/00 20130101;
F25B 2700/191 20130101; F25B 41/31 20210101; F25B 2600/2513
20130101; F25B 2341/06 20130101 |
International
Class: |
F25B 41/31 20060101
F25B041/31; F25B 13/00 20060101 F25B013/00 |
Claims
1-5. (canceled)
6. An air conditioner comprising: a refrigerant circuit comprising
a compressor, a condenser, a pressure-regulating valve, and an
evaporator; and refrigerant flowing through the refrigerant circuit
in an order of the compressor, the condenser, the
pressure-regulating valve, and the evaporator, wherein the
refrigerant is R32, the pressure-regulating valve comprises a case,
a diaphragm attached to an inner side of the case to partition an
interior of the case, a flow path provided by partitioning the
interior of the case by the diaphragm, the flow path causing the
refrigerant flowing from the condenser to flow to the evaporator, a
pressure reference chamber partitioned from the flow path by the
diaphragm and filled with inert gas, a valve portion disposed in
the flow path, and a partition member disposed in the flow path,
the pressure-regulating valve is configured to adjust a degree of
opening of the valve portion to adjust a flow rate of the
refrigerant flowing through the flow path, and the valve portion is
configured to increase the degree of opening when a pressure in the
flow path is higher than a pressure in the pressure reference
chamber, and reduce the degree of opening when the pressure in the
flow path is lower than the pressure in the pressure reference
chamber, the valve portion comprises a valve body connected to the
diaphragm, and a valve seat provided in the partition member, and
the pressure-regulating valve is configured to cause the
refrigerant to flow into the pressure-regulating valve also when
the valve body is in contact with the valve seat, wherein the
pressure-regulating valve comprises a capillary, and the capillary
is disposed in parallel with the valve portion in the refrigerant
circuit.
7. The air conditioner according to claim 6, wherein an amount of
the refrigerant flowing through the refrigerant circuit is 300 g or
more and 500 g or less.
8. The air conditioner according to claim 6, wherein the compressor
is configured to variably control a number of rotations.
Description
TECHNICAL FIELD
[0001] The present invention relates to air conditioners.
BACKGROUND ART
[0002] Air conditioners that reduce refrigerant consumption with
the use of low global warming potential (GWP) refrigerant are
desired in consideration of global environment. Used as the
refrigerant enabling such air conditioners that reduce refrigerant
consumption with the use of low GWP refrigerant is R32. R32 is
refrigerant which has a small politropic exponent and whose
temperature easily increases when discharged from a compressor. The
use of R32 as refrigerant thus easily increases the temperature of
the refrigerant discharged from the compressor at high outside
temperature and at high condensation temperature. Since an increase
in the temperature of the refrigerant discharged from the
compressor may lead to a failure of the compressor, the temperature
of the refrigerant discharged from the compressor is desired not to
exceed a set temperature in order to prevent a failure of the
compressor.
[0003] In a conventional air conditioner using R32 as refrigerant,
thus, a linear expansion valve (LEV) is used to adjust the
temperature of the refrigerant discharged from a compressor.
Specifically, a microcomputer controls the degree of opening of the
LEV based on a signal from a thermistor that has detected the
temperature of the refrigerant discharged from the compressor to
adjust the temperature of the refrigerant discharged from the
compressor not to exceed the set temperature.
[0004] For example, Japanese Patent Laying-Open No. 2016-109356
(PTL 1) discloses an air conditioner that uses R32 as refrigerant
and includes an LEV.
CITATION LIST
Patent Literature
[0005] PTL 1: Japanese Patent Laying-Open No. 2016-109356
SUMMARY OF INVENTION
Technical Problem
[0006] The air conditioner disclosed in the above literature has a
long response time of the temperature of the refrigerant discharged
from the compressor with respect to the adjustment of the degree of
opening of the LEV. Consequently, the adjustment of the degree of
opening of the LEV may not keep up with an increase in the
temperature of the refrigerant discharged from the compressor,
allowing the temperature of the refrigerant discharged from the
compressor to exceed the set temperature. A reduced amount of
refrigerant may lead to a shorter response time of the temperature
of the refrigerant discharged from the compressor with respect to
the adjustment of the degree of opening of the LEV. As a result,
even when the degree of opening of the LEV is adjusted to allow the
temperature of the refrigerant discharged from the compressor to be
equal to the set temperature, a phenomenon (hunting) occurs in
which the temperature of the refrigerant discharged from the
compressor exceeds or falls below the set temperature.
[0007] The present invention has been made in view of the above
problem and has an object to provide an air conditioner that can
suppress an increase in the temperature of refrigerant discharged
from a compressor and reduce refrigerant consumption with the use
of low GWP refrigerant.
[0008] Solution to Problem
[0009] An air conditioner of the present invention includes a
refrigerant circuit and refrigerant. The refrigerant circuit has a
compressor, a condenser, a pressure-regulating valve, and an
evaporator. The refrigerant flows through the refrigerant circuit
in the order of the compressor, the condenser, the
pressure-regulating valve, and the evaporator. The refrigerant is
R32. The pressure-regulating valve includes a flow path causing the
refrigerant flowing from the condenser to flow to the evaporator, a
pressure reference chamber partitioned from the flow path and
tilled with inert gas, and a valve portion disposed in the flow
path. The pressure-regulating valve is configured to adjust a
degree of opening of the valve portion to adjust a flow rate of the
refrigerant flowing through the flow path. The valve portion is
configured to increase the degree of opening when a pressure in the
flow path is higher than a pressure in the pressure reference
chamber and reduce the degree of opening when the pressure in the
flow path is lower than the pressure in the pressure reference
chamber.
Advantageous Effects of Invention
[0010] The air conditioner of the present invention sets the
pressure in the pressure reference chamber to the pressure in the
flow path where the temperature of the refrigerant discharged from
the compressor is a set temperature, and accordingly can increase
the degree of opening of the valve portion when the pressure in the
flow path is higher than the pressure in the pressure reference
chamber, thus suppressing the temperature of the refrigerant
discharged from the compressor exceeding the set temperature. Also,
the degree of opening of the valve portion is adjusted before the
temperature of the refrigerant discharged from the compressor
exceeds the set temperature, thus suppressing the generation of
hunting. R32 is low GWP refrigerant. Therefore, an air conditioner
that reduces refrigerant consumption with the use of low GWP
refrigerant can be achieved.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 schematically shows the structure of a refrigerant
circuit of an air conditioner in Embodiment 1 of the present
invention.
[0012] FIG. 2 is a sectional view schematically showing the
structure of a pressure-regulating valve of the air conditioner in
Embodiment 1 of the present invention.
[0013] FIG. 3 is a sectional view for illustrating an operation of
a valve portion of the air conditioner in Embodiment 1 of the
present invention.
[0014] FIG. 4 schematically shows the structure of a refrigerant
circuit of an air conditioner in a comparative example.
[0015] FIG. 5 schematically shows the structure of a refrigerant
circuit of an air conditioner in Embodiment 2 of the present
invention,
[0016] FIG. 6 schematically shows the structure of a refrigerant
circuit of an air conditioner in Embodiment 3 of the present
invention.
[0017] FIG. 7 is a sectional view schematically showing the
structure of a pressure-regulating valve of a modification of the
air conditioner in Embodiment 3 of the present invention.
DESCRIPTION OF EMBODIMENTS
[0018] Embodiments of the present invention will be described below
with reference to the drawings.
Embodiment 1
[0019] A configuration of an air conditioner 10 in Embodiment 1 of
the present invention will be described with reference to FIG. 1.
Air conditioner 10 of the present embodiment is a device dedicated
to cooling. That is to say, air conditioner 10 of the present
embodiment has a cooling function and does not have a heating
function.
[0020] Air conditioner 10 of the present embodiment mainly includes
a compressor 1, a condenser 2, a pressure-regulating valve 3, an
evaporator 4, a blower for condenser 5, a blower for evaporator 6,
pipes PI1 to PI4, and refrigerant. Compressor 1, condenser 2,
pressure-regulating valve 3, and blower for condenser 5 are
accommodated in an outdoor unit 11. Evaporator 4 and blower for
evaporator 6 are accommodated in an indoor unit 12.
[0021] Refrigerant circuit 13 has compressor 1, condenser 2,
pressure-regulating valve 3, and evaporator 4. Compressor 1,
condenser 2, pressure-regulating valve 3, and evaporator 4
communicated with each other through pipes PI1 to PI4 constitute
refrigerant circuit 13. Specifically, compressor 1 and condenser 2
are connected to each other by pipe PI1. Condenser 2 and
pressure-regulating valve 3 are connected to each other by pipe
PI2. Pressure-regulating valve 3 and evaporator 4 are connected to
each other by pipe PI3. Evaporator 4 and compressor 1 are connected
to each other by pipe PI4.
[0022] Refrigerant circuit 13 is configured to allow refrigerant to
circulate therethrough in the order of compressor 1, pipe PI1,
condenser 2, pipe PI2, pressure-regulating valve 3, pipe PI3,
evaporator 4, and pipe PI4. That is to say, refrigerant flows
through refrigerant circuit 13 in the order of compressor 1,
condenser 2, pressure-regulating valve 3, and evaporator 4.
Refrigerant is R32. The amount of the refrigerant flowing through
refrigerant circuit 13 is preferably 300 g or more and 500 g or
less.
[0023] Compressor 1 is configured to compress refrigerant.
Compressor 1 is also configured to compress the sucked refrigerant
and discharge the compressed refrigerant. Compressor 1 is
configured to have a variable capacity. Compressor 1 of the present
embodiment is configured to variably control the number of
rotations. Specifically, the drive frequency of compressor 1 is
changed based on an instruction from a controller (not shown), so
that the number of rotations of compressor 1 is adjusted. This
changes the capacity of compressor 1. The capacity of compressor 1
is an amount by which refrigerant is fed per unit time. That is to
say, compressor 1 can perform a high-capacity operation and a
low-capacity operation. In the high-capacity operation, an
operation is performed by setting the drive frequency of compressor
1 high to increase the flow rate of refrigerant circulating through
refrigerant circuit 13. In the low-capacity operation, an operation
is performed by setting the drive frequency of compressor 1 low to
reduce the flow rate of refrigerant circulating through refrigerant
circuit 13.
[0024] Condenser 2 is configured to condense the refrigerant
compressed by compressor 1. Condenser 2 is an air-heat exchanger
formed of a pipe and a fin. Pressure-regulating valve 3 is
configured to decompress the refrigerant condensed by condenser 2.
Pressure-regulating valve 3 has the function as an expansion valve.
Pressure-regulating valve 3 is also a mechanical pressure control
valve. Pressure-regulating valve 3 is also configured to adjust the
flow rate of the refrigerant flowing through pressure-regulating
valve 3. The flow rate of the refrigerant flowing through
pressure-regulating valve 3 is a flow rate per unit time.
Evaporator 4 is configured to evaporate the refrigerant
decompressed by pressure-regulating valve 3. Evaporator 4 is an
air-heat exchanger formed of a pipe and a fin.
[0025] Blower for condenser 5 is configured to adjust a heat
exchange amount between the outdoor air and refrigerant in
condenser 2. Blower for condenser 5 is formed of a fan 5a and a
motor 5b. Motor Sb may be configured to rotate fan 5a such that the
number of rotations of fan 5a is variable. Motor 5b may also be
configured to rotate fan 5a such that the number of rotations of
fan 5a is constant. Blower for evaporator 6 is configured to adjust
a heat exchange amount between the indoor air and refrigerant in
evaporator 4. Blower for evaporator 6 is formed of a fan 6a and a
motor 6b. Motor 6b may be configured to rotate fan 6a such that the
number of rotations of fan 6a is variable. Motor 6b may be
configured to rotate fan 6a such that the number of rotations of
fan 6a is constant.
[0026] With reference to FIGS. 1 and 2, the configuration of
pressure-regulating valve 3 in the present embodiment will be
described in detail.
[0027] Pressure-regulating valve 3 includes a case 31, a diaphragm
32, a flow path 33, a valve portion 34, a spring 35, and a
partition member 36. Pressure-regulating valve 3 is configured to
adjust the degree of opening of valve portion 34 to adjust the flow
rate of the refrigerant flowing through flow path 33.
[0028] Diaphragm 32 is attached to the inner side of case 31 to
partition the interior of case 31. Case 31 has a first chamber S1
and a second chamber S2 partitioned by diaphragm 32.
[0029] First chamber S1 has flow path 33 which causes the
refrigerant flowing from condenser 2 to flow to evaporator 4.
Specifically, first chamber S1 has a flow inlet portion 31a and a
flow outlet portion 31b. Flow inlet portion 31a is connected to
pipe PI2. Flow outlet portion 31b is connected to pipe PI3. First
chamber S1 is configured to allow the refrigerant flowing through
the refrigerant circuit to flow from pipe PI2 through flow inlet
portion 31a into first chamber S1 and then flow through outlet
portion 31b to pipe PI3. That is to say, the refrigerant flowing
through the refrigerant circuit flows into first chamber S1 from
flow inlet portion 31a and flows out of flow outlet portion 31b, as
indicated by arrows A1 in FIG. 2. In the present embodiment, the
path from flow inlet portion 31a to flow outlet portion 31b forms
flow path 33 for refrigerant.
[0030] The pressure of first chamber S1 is a pressure of the
refrigerant in flow path 33. Since the pressure of first chamber S1
is a pressure of the refrigerant flowing thereinto from condenser
2, it is a pressure of high-pressure-side refrigerant flowing
through refrigerant circuit 13. Pressure-regulating valve 3 is
accordingly a high-pressure pressure-regulating valve.
[0031] Second chamber S2 forms a pressure reference chamber S2.
Pressure reference chamber S2 is partitioned from flow path 33.
Pressure reference chamber S2 is filled with inert gas. Pressure
reference chamber S2 is hermetically sealed while being filled with
inert gas. The pressure in pressure reference chamber S2 is a
pressure of the inert gas. The inert gas is, for example, nitrogen
or helium. Nitrogen is advantageous in low cost. Helium is
advantageous in high level of safety. The pressure in pressure
reference chamber S2 is, for example, 3 MPa or more and 4 MPa or
less.
[0032] Diaphragm 32 is configured to deform in the direction
indicated by a double-pointed arrow A2 in FIG. 2 due to a pressure
difference between the pressure of first chamber S1 and the
pressure of second chamber S2, that is, a pressure difference
between the pressure of the refrigerant in flow path 33 and the
pressure of the inert gas in pressure reference chamber S2.
Specifically, diaphragm 32 is configured to curve in a projecting
manner toward pressure reference chamber S2 when the pressure of
the refrigerant in flow path 33 is higher than the pressure of the
inert gas in pressure reference chamber S2. In contrast, diaphragm
32 is configured to be planar when the pressure of the refrigerant
in flow path 33 is equal to or lower than the pressure of the inert
gas in pressure reference chamber S2. That is to say, in this case,
diaphragm 32 does not curve in a projecting manner toward pressure
reference chamber S2.
[0033] Valve portion 34, spring 35, and partition member 36 are
disposed in first chamber S1. Partition member 36 is configured to
partition first chamber S1 into a first region on the flow inlet
portion 31a side arid a second region on the flow outlet portion
31b side. That is to say, partition member 36 is disposed between
flow inlet portion 31a and flow outlet portion 31b in flow path 33
extending from flow inlet portion 31a to flow outlet portion
31b.
[0034] Valve portion 34 has a valve body 34a and a valve seat 34b.
Valve portion 34 is configured to adjust the degree of opening by
the gap between valve body 34a and valve seat 34b. Valve body 34a
is formed in a shaft shape. One end (first end) of valve body 34a
is connected to diaphragm 32. The other end (second end) of valve
body 34a is connected to spring 35. Valve body 34a is configured to
move in the direction indicated by a double-pointed arrow A3 in
FIG. 2 due to the deformation of diaphragm 32. That is to say,
valve body 34a is configured to move in the axial direction of
valve body 34a due to the deformation of diaphragm 32. Valve body
34a has a tapered shape with a cross-section continuously
decreasing from the one end to the other end. Valve body 34a is
formed in a truncated cone shape and is formed with a diameter
continuously decreasing in the axial direction toward valve seat
34b.
[0035] Valve seat 34b is provided in partition member 36. Valve
seat 34b is disposed between flow inlet portion 31a and flow outlet
portion 31b in flow path 33 extending from flow inlet portion 31a
to flow outlet portion 31b. Valve seat 34b is provided around a
valve hole 37 passing through valve seat 34b. Valve body 34a moves
in the axial direction of valve body 34a clue to the deformation of
diaphragm 32 and accordingly leaves valve seat 34b, thereby opening
valve hole 37. Specifically, when the pressure of the refrigerant
in flow path 33 exceeds the pressure of the inert gas in pressure
reference chamber S2, diaphragm 32 curves in a projecting manner
toward pressure reference chamber S2. This causes valve body 34a
connected to diaphragm 32 to move toward pressure reference chamber
S2 in the axial direction of valve body 34a. The other end of valve
body 34a accordingly leaves valve seat 34b to expose valve hole 37
from valve body 34a, thereby opening valve hole 37.
[0036] Valve seat 34b is configured such that each of the surface
(upper surface) on the first region side of first chamber S1 and
the surface (lower surface) on the second region side of first
chamber S1 becomes dented. That is to say, valve seat 34b has a
dent on each of the first region side and the second region side of
first chamber S1. In valve seat 34b, the bottom of the dent on the
first region side of first chamber S1 and the bottom of the dent on
the second region side of first chamber S1 are communicated with
each other. The bottom of the dent on the first region side of
first chamber S1 and the bottom of the dent on the second region
side of first chamber S1 which are communicated with each other
define valve hole 37.
[0037] Specifically, valve seat 34b is formed such that each of the
surface on the first region side of first chamber S1 and the
surface on the second region side of first chamber S1 is formed in
a cone shape. Valve seat 34b is formed in a cone shape such that
the surface on the first region side of first chamber S1 has a
diameter continuously decreasing toward the second region of first
chamber S1. The surface of valve seat 34b on the first region side
of first chamber S1 is formed in a cone shape to have a diameter
continuously decreasing toward second region of first chamber
S1.
[0038] Valve portion 34 is configured to increase the degree of
opening when the pressure in flow path 33 is higher than the
pressure in pressure reference chamber S1. That is to say, valve
portion 34 is configured as follows. When the pressure in flow path
33 is higher than the pressure in pressure reference chamber S2,
valve body 34a moves toward diaphragm 32 in the axial direction of
valve body 34a to increase the gap between valve body 34a arid
valve seat 34b, thereby increasing the degree of opening. Valve
portion 34 is also configured to reduce the degree of opening when
the pressure in flow path 35 is lower than the pressure in pressure
reference chamber S2. That is to say, valve portion 34 is
configured as follows. When the pressure in flow path 35 is lower
than the pressure in pressure reference chamber S2, valve body 34a
moves toward spring 35 in the axial direction of valve body 34a to
reduce the gap between valve body 34a and valve seat 34b, thereby
reducing the degree of opening.
[0039] Valve portion 34 is configured to continuously change the
size of the gap between valve body 34a and valve seat 34b by valve
body 34a moving in the axial direction of valve body 34a due to the
deformation of diaphragm 32. That is to say, valve portion 34 is
configured to increase or reduce the degree of opening of valve
portion 34 in proportional to the amount of movement in the axial
direction of valve body 34a.
[0040] Spring 35 is connected to the other end of valve body 34a
and the bottom of case 31. Spring 35 is configured to bias valve
body 34a toward the bottom of case 31 by elastic force.
[0041] A small hole 38 is provided in partition member 36. Small
hole 38 is provided to pass through partition member 36. Small hole
38 defines a part of flow path 33. Since small hole 38 is not
closed by valve body 34a and is open constantly, refrigerant can
constantly flow through small hole 38 front the first region to the
second region in first chamber S1. In the present embodiment, small
hole 38 has the function as a capillary. That is to say, the
refrigerant is decompressed by flowing through small hole 38.
[0042] A flow of refrigerant in the refrigerant circuit of air
conditioner 10 of the present embodiment will now he described.
[0043] With reference to FIG. 1, the refrigerant that has flowed
into compressor 1 is compressed by compressor 1 to turn into
high-temperature, high-pressure gas refrigerant. The
high-temperature, high-pressure gas refrigerant discharged from
compressor 1 flows through pipe PI1 into condenser 2. The
refrigerant that has flowed into condenser 2 is subjected to heat
exchange with the air in condenser 2. Specifically, in condenser 2,
the refrigerant is condensed by heat dissipation to the air, and
the air is heated by the refrigerant. High-pressure liquid
refrigerant condensed by condenser 2 flows through pipe PI2 into
pressure-regulating valve 3.
[0044] The refrigerant that has flowed into pressure-regulating
valve 3 is decompressed by pressure-regulating valve 3 to turn into
low-pressure gas-liquid two-phase refrigerant. The refrigerant
decompressed by pressure-regulating valve 3 flows through pipe PI3
into evaporator 4. The refrigerant that has flowed into evaporator
4 is subjected to heat exchange with the air in evaporator 4.
Specifically, in evaporator 4, the air is cooled by the
refrigerant, and the refrigerant turns into low-pressure gas
refrigerant. The refrigerant decompressed by evaporator 4 to turn
into low-pressure gas flows through pipe PI4 into compressor 1. The
refrigerant flowing into compressor 1 is compressed and pressurized
again and subsequently discharged from compressor 1.
[0045] With reference to FIGS. 2 and 3, the operation of
pressure-regulating valve 3 in the present embodiment will now be
described in detail.
[0046] When the pressure of the refrigerant in flow path 33 is
equal to or lower than the pressure of the inert gas in pressure
reference chamber S2, diaphragm 32 is maintained in a planar
manner, so that valve body 34a is in contact with valve seat 34b.
This maintains the state in which valve hole 37 is closed by valve
body 34a. Valve portion 34 is closed in this state.
[0047] When the pressure of the refrigerant in flow path 33 is
higher than the pressure of the inert gas in pressure reference
chamber S2, diaphragm 32 deforms in a projecting manner toward
pressure reference chamber S2. The deformation of diaphragm 32
causes valve body 34a to move toward pressure reference chamber S2
in the axial direction of valve body 34a. Consequently, valve body
34a leaves valve seat 34b. In this state, valve portion 34 is
opened. Further, when valve body 34a moves toward pressure
reference chamber S2 in the axial direction of valve body 34a due
to the deformation of diaphragm 32, the gap between valve body 34a
and valve seat 34b increases. That is to say, the degree of opening
of valve portion 34 increases. This increases the amount of
refrigerant flowing through pressure-regulating valve 3, thus
increasing the amount of refrigerant flowing into evaporator 4. The
degree of superheat (SH) accordingly decreases. As a result, an
increase in the temperature of the refrigerant discharged from
compressor 1 can he suppressed.
[0048] The amount of movement in the axial direction of valve body
34a can be adjusted by the pressure of the refrigerant in flow path
33, the pressure of the inert gas in pressure reference chamber S2,
and the biasing force of spring 35 connected to valve body 34a. The
degree of opening of valve portion 34 can be adjusted by the gap
between valve body 34a and valve seat 34b. The amount of the
refrigerant flowing through pressure-regulating valve 3 can thus be
adjusted by adjusting the amount of movement in the axial direction
of valve body 34a and the degree of opening of valve portion
34.
[0049] The function and effect of the present embodiment will now
be described in comparison with those of a comparative example. The
same components as those of Embodiment 1 will he denoted by the
same reference signs, and description thereof will not be repeated,
unless otherwise noted.
[0050] With reference to FIG. 4, air conditioner 10 of the
comparative example differs from air conditioner 10 of the present
embodiment in that it includes a linear expansion valve (LEV) 30, a
thermistor 7, and a microcomputer 8. In air conditioner 10 of the
comparative example, microcomputer 8 controls the degree of opening
of LEV 30 based on a signal from thermistor 7 that has detected the
temperature of the refrigerant discharged from compressor 1, so
that the temperature of the refrigerant discharged from compressor
1 is adjusted not to exceed a set temperature (a temperature set to
prevent a failure of compressor 1).
[0051] In air conditioner 10 of the present embodiment, refrigerant
is R32. R32 is refrigerant which has a small politropic exponent
and whose temperature easily increases when discharged from
compressor 1. Thus, when R32 is used as refrigerant, the
temperature of the refrigerant discharged from compressor 1
increases easily at high outside air (high outside air temperature)
and at high condensation temperature.
[0052] Air conditioner 10 of the present embodiment sets the
pressure in pressure reference chamber S2 to the pressure in flow
path 33 where the temperature of the refrigerant discharged from
compressor 1 is the set temperature (the temperature set to prevent
a failure of compressor 1), thereby increasing the degree of
opening of valve portion 34 when the pressure in flow path 33 is
higher than the pressure in pressure reference chamber S2. This can
suppress the temperature of the refrigerant discharged from
compressor 1 exceeding the set temperature. The amount of the
refrigerant flowing into evaporator 4 can also be increased by
increasing the amount of the refrigerant flowing through
pressure-regulating valve 3, thus reducing the degree of superheat.
An increase in the temperature of the refrigerant discharged from
compressor 1 can thus be suppressed. Also, the generation of
hunting can be suppressed by adjusting the degree of opening of
valve portion 34 before the temperature of the refrigerant
discharged from compressor 1 exceeds the set temperature. R32 is
low GWP refrigerant. Consequently, air conditioner 10 that reduces
refrigerant consumption with the use of low GWP refrigerant can be
achieved.
[0053] Air conditioner 10 of the comparative example needs LEV 30,
thermistor 7, and microcomputer 8 to adjust the temperature of the
refrigerant discharged from compressor 1, leading to a complex
configuration of air conditioner 10. Also, the cost of
manufacturing air conditioner 10 is increased. Contrastingly, in
air conditioner 10 of the present embodiment, pressure-regulating
valve 3 can adjust the temperature of the refrigerant discharged
from compressor 1, leading to a simple configuration of air
conditioner 10. Also, the cost of manufacturing air conditioner 10
is reduced.
[0054] In air conditioner 10 of the present embodiment,
pressure-regulating valve 3 can adjust the flow rate of the
refrigerant flowing: through flow path 33 by adjusting the degree
of opening of valve portion 34. Thus, the generation of hunting can
be suppressed more than in the case where valve portion .34 is
merely opened/closed (ON/OFF). Also, the controllability of the
flow rate of refrigerant can be improved.
[0055] In air conditioner 10 of the present embodiment, the amount
of refrigerant flowing through refrigerant circuit 13 is 300 g or
more and 500 g or less. According to the documents provided by the
Ministry of Economy, Trade and Industry (documents related to a
method of estimating emissions outside notification, 2003), the
average refrigerant chlorofluorocarbon (CFC) charge amount of a
room air conditioner is 800 g. Air conditioner 10 of the present
embodiment can thus reduce the amount of refrigerant to about a
half of 800 g that is the average refrigerant CFC charge amount of
a room air conditioner. If the amount of refrigerant is 400
g.+-.100 g, where 400 g is a half of the average refrigerant CFC
charge amount of a room air conditioner, the refrigerant
consumption can be reduced while maintaining the cooling
capacity.
[0056] In air conditioner 10 of the comparative example, a reduced
amount of refrigerant results in a shorter response time of the
temperature of the refrigerant discharged from compressor 1 with
respect to the adjustment of the degree of opening of LEV 30, so
hunting may occur at the set temperature. Contrastingly, air
conditioner 10 of the present embodiment increases the degree of
opening of valve portion 34 with reference to the pressure in
pressure reference chamber S2, thereby suppressing the generation
of hunting with respect to the set temperature even when the amount
of refrigerant decreases. Controllability can thus be improved.
[0057] In air conditioner 10 of the present embodiment, compressor
1 can variably control the number of rotations. Power consumption
can thus be reduced by variably controlling the number of rotations
of compressor 1. Also, even when the temperature of the refrigerant
discharged from compressor 1 increases due to an increase in the
number of rotations of compressor 1, an increase in the temperature
of the refrigerant discharged from compressor 1 can be suppressed
by increasing the degree of opening of valve portion 34 with
reference to the pressure in pressure reference chamber S2.
Embodiment 2
[0058] The same components as those of Embodiment 1 will be denoted
by the same reference signs in Embodiment 2, and description
thereof will not be repeated, unless otherwise noted.
[0059] With reference to FIG. 5, air conditioner 10 of Embodiment 2
of the present invention differs from air conditioner 10 of
Embodiment 1 in the configuration of pressure-regulating valve
3.
[0060] In air conditioner 10 of the present embodiment,
pressure-regulating valve 3 includes a capillary 39. Capillary 39
is connected to case 31 of pressure-regulating valve 3 and
evaporator 4. The configuration in case 31 of pressure-regulating
valve 3 is identical to the configuration of Embodiment 1.
Capillary 39 is disposed between valve portion 34 and evaporator 4
in refrigerant circuit 13. Capillary 39 can thus decompress the
refrigerant.
[0061] The present embodiment can adjust the decompression of
refrigerant by capillary 39. This leads to easier adjustment of the
decompression of the refrigerant.
Embodiment 3
[0062] The same components as those of Embodiment 1 will be denoted
by the same reference signs in Embodiment 3, and description
thereof will not be repeated, unless otherwise noted.
[0063] With reference to FIG. 6, air conditioner 10 of Embodiment 3
of the present invention differs from air conditioner 10 of
Embodiment 1 in the configuration of pressure-regulating valve
3.
[0064] In air conditioner 10 of the present embodiment,
pressure-regulating valve 3 includes capillary 39. Capillary 39 is
connected in parallel with case 31 of pressure-regulating valve 3
in refrigerant circuit 13. The configuration in case 31 of
pressure-regulating valve 3 is identical to the configuration of
Embodiment 1. Capillary 39 is disposed in parallel with valve
portion 34 in refrigerant circuit 13. Capillary 39 can thus
decompress the refrigerant.
[0065] The present embodiment can accordingly adjust the
decompression of refrigerant by capillary 39. The adjustment of the
decompression of refrigerant can thus be simplified.
[0066] With reference to FIG. 7, a modification of air conditioner
10 of Embodiment 3 will now be described. This modification differs
from Embodiment 1 in that small hole 38 is not provided. In this
modification, capillary 39 is disposed in parallel with valve
portion 34 in refrigerant circuit 13, and accordingly, capillary 39
can cause refrigerant to constantly flow through refrigerant
circuit 13 even when small hole 38 of Embodiment 1 is not
provided.
[0067] Capillary 39 can adjust the decompression of refrigerant
more easily than small hole 38 of Embodiment 1. In the modification
of air conditioner 10 of the present embodiment, thus, capillary 39
can adjust the decompression of refrigerant easily.
[0068] It is to be understood that the embodiments disclosed herein
have been presented for the purpose of illustration and
non-restrictive in every respect. It is therefore intended that the
scope of the present invention is defined by claims, not only by
the embodiments described above, and encompasses all modifications
and variations equivalent in meaning and scope to the claims.
REFERENCE S1GNS LIST
[0069] 1 compressor, 2 condenser, 3 pressure-regulating valve, 4
evaporator, 5 blower for condenser, 6 blower for evaporator, 7
thermistor, 8 microcomputer, 9 capillary, 10 air conditioner, 11
outdoor unit, 12 indoor unit, 13 refrigerant circuit, 31 case, 31a
flow inlet portion, 31b flow outlet portion, 32 diaphragm, 33 flow
path, 34a valve body, 34b valve seat, 35 spring, 36 partition
member, 37 valve hole, 38 small hole, 39 capillary, S1 first
chamber, S2 second chamber (pressure reference chamber).
* * * * *