U.S. patent application number 13/321866 was filed with the patent office on 2012-03-15 for heating dedicated air conditioner.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. Invention is credited to Hidehiko Kinoshita, Junichi Shimoda.
Application Number | 20120060532 13/321866 |
Document ID | / |
Family ID | 43222437 |
Filed Date | 2012-03-15 |
United States Patent
Application |
20120060532 |
Kind Code |
A1 |
Shimoda; Junichi ; et
al. |
March 15, 2012 |
HEATING DEDICATED AIR CONDITIONER
Abstract
A heating dedicated air conditioner includes a compression
mechanism, an indoor heat exchanger, an outdoor heat exchanger, an
expansion mechanism provided between one end of the indoor heat
exchanger and one end of the outdoor heat exchanger, a four-way
switching valve switchable between first and second states of
connection between the compressor and the heat exchangers, a fan
ventilating the indoor heat exchanger, and a control unit
controlling at least the compressor, the expansion mechanism, the
four-way switching valve, and the fan. The control unit switches
the four-way switching valve to the second state in a test
operation mode, which includes a drain water inhibited interval
during which drain water inhibition control is performed. The
control unit operates the compressor and stops the fan when the
drain water inhibition control is performed.
Inventors: |
Shimoda; Junichi; ( Osaka,
JP) ; Kinoshita; Hidehiko; ( Osaka, JP) |
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
43222437 |
Appl. No.: |
13/321866 |
Filed: |
May 26, 2010 |
PCT Filed: |
May 26, 2010 |
PCT NO: |
PCT/JP2010/003531 |
371 Date: |
November 22, 2011 |
Current U.S.
Class: |
62/150 |
Current CPC
Class: |
F24F 11/30 20180101;
F24F 11/62 20180101; F25B 49/02 20130101; F25B 2309/06 20130101;
F25B 2600/025 20130101; F25B 13/00 20130101; F25B 2600/2513
20130101; F25B 2700/1931 20130101; F24F 11/65 20180101; F24F 1/0003
20130101; F25B 2313/0293 20130101; F25B 9/008 20130101; F25B
2313/02741 20130101; F25B 2600/2507 20130101 |
Class at
Publication: |
62/150 |
International
Class: |
F25D 21/00 20060101
F25D021/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 29, 2009 |
JP |
2009-130529 |
Claims
1. A heating dedicated air conditioner, comprising: a compression
mechanism; an indoor heat exchanger; an outdoor heat exchanger; an
expansion mechanism disposed between one end of the indoor heat
exchanger and one end of the outdoor heat exchanger; a four-way
switching valve switchable between a first state in which a
discharge side of the compression mechanism and an other end of the
indoor heat exchanger are connected and a suction side of the
compression mechanism and an other end of the outdoor heat
exchanger are connected, and a second state in which the discharge
side of the compression mechanism and the other end of the outdoor
heat exchanger are connected and the suction side of the
compression mechanism and the other end of the indoor heat
exchanger are connected; a fan arranged to ventilate the indoor
heat exchanger; and a control unit configured to control at least
the compression mechanism, the expansion mechanism, the four-way
switching valve, and the fan, the control unit being configured to
switch the four-way switching valve to the second state in a test
operation mode, the test operation mode including a drain water
inhibited interval during which drain water inhibition control is
performed, the control unit being configured to operate the
compression mechanism and stop the fan when the drain water
inhibition control is performed.
2. The heating dedicated air conditioner according to claim 1,
further comprising: a gas side shutoff valve disposed between the
other end of the indoor heat exchanger and the four-way switching
valve; and a pressure detector mounted to a gas refrigerant pipe,
the gas refrigerant pipe connecting the other end of the indoor
heat exchanger and the suction side of the compression
mechanism.
3. The heating dedicated air conditioner according to claim 2,
further comprising: an indoor casing; and an outdoor casing;
wherein, the indoor heat exchanger and the fan being housed in the
indoor casing, and the compression mechanism, the outdoor heat
exchanger, the expansion mechanism, the four-way switching valve,
the gas side shutoff valve, and the pressure detector being housed
in the outdoor casing.
4. The heating dedicated air conditioner according to claim 1,
further comprising: a gas-liquid separator disposed between the
suction side of the compression mechanism and the four-way
switching valve.
5. The heating dedicated air conditioner according to claim 1
wherein the drain water inhibited interval occupies 80% or more of
the entire interval of the test operation mode.
6. The heating dedicated air conditioner according to claim 5,
wherein a first interval other than the drain water inhibited
interval is a beginning interval of the entire interval of the test
operation mode.
7. The heating dedicated air conditioner according to claim 4,
wherein the drain water inhibited interval occupies 80% or more of
the entire interval of the test operation mode.
8. The heating dedicated air conditioner according to claim 7,
wherein a first interval other than the drain water inhibited
interval is a beginning interval of the entire interval of the test
operation mode.
9. The heating dedicated air conditioner according to claim 2,
further comprising: a gas-liquid separator disposed between the
suction side of the compression mechanism and the four-way
switching valve.
10. The heating dedicated air conditioner according to claim 2,
wherein the drain water inhibited interval occupies 80% or more of
the entire interval of the test operation mode.
11. The heating dedicated air conditioner according to claim 10,
wherein a first interval other than the drain water inhibited
interval is a beginning interval of the entire interval of the test
operation mode.
12. The heating dedicated air conditioner according to claim 3,
further comprising: a gas-liquid separator disposed between the
suction side of the compression mechanism and the four-way
switching valve.
13. The heating dedicated air conditioner according to claim 3,
wherein the drain water inhibited interval occupies 80% or more of
the entire interval of the test operation mode.
14. The heating dedicated air conditioner according to claim 13,
wherein a first interval other than the drain water inhibited
interval is a beginning interval of the entire interval of the test
operation mode.
Description
TECHNICAL FIELD
[0001] The present invention relates to a heating dedicated air
conditioner.
BACKGROUND ART
[0002] In the conventional art, when an air conditioner is
installed, a test operation is often performed in order to verify
whether, for example, the various equipment of the air conditioner
operates normally, the air conditioner has been constructed
correctly, and the like. For example, in an air conditioner
according to Patent Document 1 (i.e., Japanese Unexamined Patent
Application Publication No. 2001-99459), a test operation is
performed in a cooling cycle or a heating cycle; furthermore, in
this test operation, a verification is simultaneously performed to
determine whether the indoor fan is operating normally.
SUMMARY OF THE INVENTION
Technical Problem
[0003] Among the air conditioners discussed above, there are
heating dedicated air conditioners that principally perform heating
operation. In such a heating dedicated air conditioner, only
heating operation is performed, and this principally in the winter
season when the temperature is low; therefore, a drainage pipe that
serves as drain water processing equipment is often not provided
and only a drain pan is provided. Consequently, for example, in the
summertime when the temperature and humidity are high, if a test
operation of the heating dedicated air conditioner is performed in
a reverse cycle to that of the heating cycle discussed above, then
drain water from the indoor heat exchanger may overflow the drain
pan and flow into the indoor space, which would be a problem.
[0004] Accordingly, an object of the present invention is to
prevent drain water from an indoor heat exchanger from overflowing
a drain pan in a case wherein a test operation of a heating
dedicated air conditioner is performed in a reverse cycle to that
of the heating cycle, for example, in summertime when the
temperature and humidity are high.
Solution to Problem
[0005] A heating dedicated air conditioner according to a first
aspect of the present invention comprises a compression mechanism,
an indoor heat exchanger, an outdoor heat exchanger, an expansion
mechanism, a four-way switching valve, a fan, and a control unit.
The expansion mechanism is provided between one end of the indoor
heat exchanger and one end of the outdoor heat exchanger. The
four-way switching valve switches between a first state, wherein a
discharge side of the compression mechanism and an other end of the
indoor heat exchanger are connected and a suction side of the
compression mechanism and an other end of the outdoor heat
exchanger are connected, and a second state, wherein the discharge
side of the compression mechanism and the other end of the outdoor
heat exchanger are connected and the suction side of the
compression mechanism and the other end of the indoor heat
exchanger are connected. The fan ventilates the indoor heat
exchanger. The control unit controls at least the compression
mechanism, the expansion mechanism, the four-way switching valve,
and the fan. In addition, the control unit, in the test operation
mode, switches the four-way switching valve to the second state.
Furthermore, the drain water inhibited interval during which drain
water inhibition control is performed, wherein the control unit
operates the compression mechanism and stops the fan, is provided
to the test operation mode.
[0006] Here, in the heating dedicated air conditioner, if a drain
pan is disposed, for example, below the indoor heat exchanger, then
it is possible to accumulate drain water generated in the indoor
heat exchanger. In addition, for example, the expansion mechanism
is an expansion valve whose degree of opening may be fixed.
[0007] In the heating dedicated air conditioner according to the
first aspect of the invention, the control unit, in the test
operation mode, switches the four-way switching valve from the
first state to the second state and stops the fan. Thereby, for
example, in the heating dedicated air conditioner, it is possible
to prevent drain water from overflowing the drain pan even if the
drain pan alone is provided without drainage pipe that externally
discharges the drain water accumulated in the drain pan, for
example, even if test operation is performed in the summertime in a
reverse cycle to that of a heating cycle.
[0008] A heating dedicated air conditioner according to a second
aspect of the present invention is the heating dedicated air
conditioner according to the first aspect of the invention, and
further comprises a gas side shutoff valve and a pressure detector.
The gas side shutoff valve is provided between the other end of the
indoor heat exchanger and the four-way switching valve. The
pressure detector is mounted to a gas refrigerant pipe that
connects the other end of the indoor heat exchanger and the suction
side of the compression mechanism.
[0009] In the heating dedicated air conditioner according to the
second aspect of the invention, test operation in, for example, the
test operation mode is performed in the state wherein the four-way
switching valve is in the second state, namely, in the reverse
cycle to that of the heating cycle. This is because, should test
operation be performed in the heating cycle, the high pressure
between the gas side shutoff valve and the discharge side of the
compression mechanism will tend not to rise, and it might not be
possible to promptly detect whether the gas side shutoff valve is
in the open state, which is a problem. Thereby, the open/close
state of the gas side shutoff valve in the test operation mode can
be promptly detected by performing, for example, test operation in
the test operation mode in the reverse cycle to that of the heating
cycle and providing the pressure detector to the gas refrigerant
pipe that connects the other end of the indoor heat exchanger and
the suction side of the compression mechanism.
[0010] A heating dedicated air conditioner according to a third
aspect of the present invention is the heating dedicated air
conditioner according to the second aspect of the invention, and
further comprises an indoor casing and an outdoor casing. The
indoor heat exchanger and the fan are housed in the indoor casing.
The compression mechanism, the outdoor heat exchanger, the
expansion mechanism, the four-way switching valve, the gas side
shutoff valve, and the pressure detector are housed in the outdoor
casing.
[0011] In the heating dedicated air conditioner according to the
third aspect of the invention, it is possible to prevent the drain
water from overflowing the drain pan even if test operation is
performed in the summertime.
[0012] A heating dedicated air conditioner according to a fourth
aspect of the present invention is the heating dedicated air
conditioner according to any one aspect of the first through third
aspects of the invention, and further comprises a gas-liquid
separator. The gas-liquid separator is provided between the suction
side of the compression mechanism and the four-way switching
valve.
[0013] In the heating dedicated air conditioner according to the
fourth aspect of the invention, the amount of evaporation of the
refrigerant in the indoor heat exchanger decreases because the fan
is stopped. Consequently, the amount of the liquid refrigerant
increases more than when the fan is operating. Accordingly,
providing the gas-liquid separator makes it possible to prevent the
liquid from being sucked into the compressor.
[0014] A heating dedicated air conditioner according to a fifth
aspect of the present invention is the heating dedicated air
conditioner according to any one aspect of the first through fourth
aspects of the invention, wherein the drain water inhibited
interval occupies 80% or more of the entire interval of the test
operation mode.
[0015] In the heating dedicated air conditioner according to the
fifth aspect of the invention, it is possible to reduce the amount
of indoor air delivered from the fan to the indoor heat exchanger
by stopping the fan for an interval that is 80% or more of the
entire interval. Thereby, even if the fan is driven, it is possible
to prevent the drain water from overflowing the drain pan.
[0016] A heating dedicated air conditioner according to a sixth
aspect of the present invention is the heating dedicated air
conditioner according to the fifth aspect of the invention, wherein
in the test operation mode, a first interval other than the drain
water inhibited interval is a beginning interval of the entire
interval of the test operation mode.
[0017] In the heating dedicated air conditioner according to the
sixth aspect of the invention, the fan is driven during the
beginning interval in the test operation mode when the evaporation
temperature does not fall all that much. Thereby, it is possible to
prevent the drain water from overflowing the drain pan even if the
fan is driven.
Advantageous Effects of Invention
[0018] In the heating dedicated air conditioner according to the
first aspect of the invention, the control unit, in the test
operation mode, switches the four-way switching valve from the
first state to the second state and stops the fan. Thereby, for
example, in the heating dedicated air conditioner, it is possible
to prevent drain water from overflowing the drain pan even if the
drain pan alone is provided without drainage pipe that externally
discharges the drain water accumulated in the drain pan, for
example, even if test operation is performed in the summertime in a
reverse cycle to that of a heating cycle.
[0019] In the heating dedicated air conditioner according to the
second aspect of the invention, the open/close state of the gas
side shutoff valve in the test operation mode can be promptly
detected by performing, for example, test operation in the test
operation mode in the reverse cycle to that of the heating cycle
and providing the pressure detector to the gas refrigerant pipe
that connects the other end of the indoor heat exchanger and the
suction side of the compression mechanism.
[0020] In the heating dedicated air conditioner according to the
third aspect of the invention, it is possible to prevent the drain
water from overflowing the drain pan even if test operation is
performed in the summertime.
[0021] In the heating dedicated air conditioner according to the
fourth aspect of the invention, the amount of evaporation of the
refrigerant in the indoor heat exchanger decreases because the fan
is stopped. Consequently, the amount of the liquid refrigerant
increases more than when the fan is operating. Accordingly,
providing the gas-liquid separator makes it possible to prevent the
liquid from being sucked into the compressor.
[0022] In the heating dedicated air conditioner according to the
fifth and sixth aspects of the invention, even if the fan is
driven, it is possible to prevent the drain water from overflowing
the drain pan.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a system diagram of a refrigerant circuit of a
heating dedicated air conditioner.
[0024] FIG. 2 is a control block diagram of a control unit.
[0025] FIG. 3 is a flow chart that illustrates operation during a
test operation of the heating dedicated air conditioner according
to a second embodiment.
DESCRIPTION OF EMBODIMENTS
[0026] The embodiments of the present invention will now be
explained, referencing the drawings.
First Embodiment
<Configuration of Heating Dedicated Air Conditioner 1>
[0027] The heating dedicated air conditioner 1 is used to heat an
indoor space of a building by performing a vapor compression type
refrigeration cycle operation. As shown in FIG. 1, the heating
dedicated air conditioner 1 comprises a single outdoor unit 2 that
serves as a heat source unit, a single indoor unit 4 that serves as
a utilization unit and is connected to the outdoor unit 2, and a
liquid side refrigerant connection pipe 6 and a gas side
refrigerant connection pipe 7 that serve as refrigerant connection
pipes and connect the outdoor unit 2 and the indoor unit 4. Namely,
a refrigerant circuit 10 of the heating dedicated air conditioner 1
is configured by the connection of the outdoor unit 2, the indoor
unit 4, the liquid side refrigerant connection pipe 6, and the gas
side refrigerant connection pipe 7.
<Configuration of Indoor Unit 4>
[0028] First, the configuration of the indoor unit 4 will be
explained.
[0029] The indoor unit 4 is installed either by embedding it in or
suspending it from the ceiling of the indoor space of a building or
by mounting it to a wall surface of the indoor space. The indoor
unit 4 is connected to the outdoor unit 2 via the liquid side
refrigerant connection pipe 6 and the gas side refrigerant
connection pipe 7.
[0030] The indoor unit 4 principally comprises an indoor side
refrigerant circuit 10a, which constitutes part of the refrigerant
circuit 10. The indoor side refrigerant circuit 10a principally
comprises an indoor heat exchanger 42.
[0031] The indoor heat exchanger 42 is a cross fin type fin and
tube heat exchanger, which comprises a heat transfer tube and
numerous fins; during heating operation, the indoor heat exchanger
42 functions as a condenser that condenses a refrigerant (e.g., a
fluorocarbon based refrigerant) and heats indoor air. Furthermore,
during defrosting operation and during test operation, discussed
below, (i.e., in the state wherein the refrigerant circuit 10 is in
a reverse cycle to that of the heating cycle), it functions as an
evaporator that evaporates the refrigerant.
[0032] In addition, the indoor unit 4 comprises an indoor fan 43
(refer to FIG. 2). The indoor fan 43 functions as a ventilation
fan, which is for sucking the indoor air into the indoor unit 4,
causing heat to be exchanged between that air and the refrigerant
in the indoor heat exchanger 42, and then supplying that air to the
indoor space as supply air. In addition, the indoor fan 43 is
driven by a fan motor (not shown) and is capable of varying the
airflow of the air supplied to the indoor heat exchanger 42. The
fan motor is configured such that it is driven by receiving the
supply of electric power via an inverter apparatus (not shown);
furthermore, by varying the inverter frequency, which varies the
fan rotational speed, the airflow of the indoor fan 43 can be
varied.
[0033] Furthermore, below the indoor heat exchanger 42, the indoor
unit 4 is provided with a drain pan 45. The drain pan 45 serves to
receive any drain water generated in the indoor heat exchanger 42
in the state wherein the refrigerant circuit 10 is in the reverse
cycle to that of the heating cycle. Furthermore, a drainage pipe
for discharging the drain water is not provided.
<Configuration of Outdoor Unit 2>
[0034] Next, the configuration of the outdoor unit 2 will be
explained.
[0035] The outdoor unit 2 is installed in the outdoor space outside
of a building and is connected to the indoor unit 4 via the liquid
side refrigerant connection pipe 6 and the gas side refrigerant
connection pipe 7. Furthermore, the outdoor unit 2 principally
comprises an outdoor side refrigerant circuit 10b, which
constitutes part of the refrigerant circuit 10. The outdoor side
refrigerant circuit 10b principally comprises: a compressor 21; a
four-way switching valve 22; an outdoor heat exchanger 23, which
serves as a heat source heat exchanger; an outdoor expansion valve
24, which serves as an expansion mechanism; an accumulator 25; a
liquid side shutoff valve 26; and a gas side shutoff valve 27.
[0036] The compressor 21 is capable of varying the operating
capacity and is a displacement type compressor that is driven by a
compressor motor (not shown).
[0037] The four-way switching valve 22 is for the purpose of
switching the flow direction of the refrigerant and can assume a
first state (refer to the broken lines of the four-way switching
valve 22 in FIG. 1) and a second state (refer to the solid lines of
the four-way switching valve 22 in FIG. 1). In the first state, the
discharge side of the compressor 21 and the gas side of the indoor
heat exchanger 42 (specifically, the gas side refrigerant
connection pipe 7) are connected, and the suction side of the
compressor 21 (specifically, the accumulator 25) and the gas side
of the outdoor heat exchanger 23 are connected. Namely, when the
four-way switching valve 22 is in the first state, the refrigerant
circuit 10 is in the heating cycle. In the second state, the
discharge side of the compressor 21 and the gas side of the outdoor
heat exchanger 23 are connected, and the suction side of the
compressor 21 and the gas side of the indoor heat exchanger 42 are
connected. Namely, when the four-way switching valve 22 is in the
second state, the refrigerant circuit 10 is in the state wherein it
is in the reverse cycle to that of the heating cycle, that is, in
the cooling cycle state.
[0038] The outdoor heat exchanger 23 is a cross fin type fin and
tube heat exchanger, which comprises heat transfer tubes and
numerous fins. The outdoor heat exchanger 23 functions as an
evaporator that evaporates the refrigerant during the heating
operation. The gas side of the outdoor heat exchanger 23 is
connected to the four-way switching valve 22, and the liquid side
is connected to the liquid side refrigerant connection pipe 6.
Furthermore, when the four-way switching valve 22 is in the second
state, the outdoor heat exchanger 23 functions as a condenser that
condenses the refrigerant.
[0039] The outdoor expansion valve 24 is a motor operated expansion
valve that is provided between one end of the indoor heat exchanger
42 and one end of the outdoor heat exchanger 23 and is connected to
the liquid side of the outdoor heat exchanger 23. The outdoor
expansion valve 24 regulates the pressure, the flow volume, and the
like of the refrigerant that flows through the interior of the
outdoor side refrigerant circuit 10b.
[0040] The outdoor unit 2 comprises an outdoor fan 28 (refer to
FIG. 2). The outdoor fan 28 functions as a ventilation fan, which
is for sucking outdoor air into the outdoor unit 2, causing heat to
be exchanged between that air and the refrigerant in the outdoor
heat exchanger 23, and then discharging that air to the outdoor
space. In addition, the outdoor fan 28 is capable of varying the
amount of the outdoor air supplied to the outdoor heat exchanger
23, and is a propeller fan that is driven by a fan motor (not
shown).
[0041] The accumulator 25 is a vessel that is provided between the
four-way switching valve 22 and the suction side of the compressor
21 and is capable of accumulating surplus refrigerant generated
inside the refrigerant circuit 10 in accordance with fluctuations
in the operating loads of the indoor unit 4.
[0042] The liquid side shutoff valve 26 and the gas side shutoff
valve 27 are provided to a connection port that connects to
external equipment and pipe (specifically, the liquid side
refrigerant connection pipe 6 and the gas side refrigerant
connection pipe 7). The liquid side shutoff valve 26 is connected
to the outdoor heat exchanger 23. The gas side shutoff valve 27 is
connected to the four-way switching valve 22. The liquid side
shutoff valve 26 and the gas side shutoff valve 27 have a function
that seals the refrigerant with which the outdoor unit 2 is
initially filled. Generally, when a builder mounts the heating
dedicated air conditioner 1, he or she completes the refrigerant
circuit 10 by connecting onsite the indoor unit 4 and the outdoor
unit 2 using the liquid side refrigerant connection pipe 6 and the
gas side refrigerant connection pipe 7 and, afterward, manually
sets the liquid side shutoff valve 26 and the gas side shutoff
valve 27 to an open state. Thereby, the refrigerant that is sealed
inside the outdoor unit 2 (specifically, the outdoor heat exchanger
23) is made to spread to the refrigerant circuit 10.
[0043] In addition, the outdoor unit 2 is provided with a
refrigerant pressure sensor 33, which detects the pressure of the
refrigerant between the four-way switching valve 22 and the gas
side shutoff valve 27.
<Configuration of Liquid Side Refrigerant Connection Pipe 6 and
Gas Side Refrigerant Connection Pipe 7>
[0044] The liquid side refrigerant connection pipe 6 and the gas
side refrigerant connection pipe 7 are refrigerant pipes that are
laid onsite when the heating dedicated air conditioner 1 is
installed at an installation location inside a building;
refrigerant pipes of various lengths and diameters are used for the
pipes 6, 7 in accordance with the installation conditions such as
the installation location and the particular combination of the
outdoor unit 2 and indoor unit 4 to be configured.
<Configuration of Control Unit 9>
[0045] A control unit 9 comprises a microcomputer, memory, and the
like and, as shown in FIG. 2, comprises an indoor control unit 9a
and an outdoor control unit 9b. The indoor control unit 9a controls
the operation of the various equipment (specifically, the indoor
fan 43 and the like) that constitutes the indoor unit 4. The
outdoor control unit 9b controls the operation of the various
equipment (specifically, the compressor 21, the outdoor fan 28, and
the like) that constitutes the outdoor unit 2.
[0046] The indoor control unit 9a is capable of transmitting
control signals to and receiving control signals from a remote
controller (not shown), which is for separately operating the
indoor unit 4. In addition, the indoor control unit 9a and the
outdoor control unit 9b are configured such that they can transmit
control signals between and receive control signals from one
another via a transmission line. Furthermore, the control unit 9,
which comprises the indoor control unit 9a and the outdoor control
unit 9b, is connected to the refrigerant pressure sensor 33 such
that the control unit 9 can receive a detection signal therefrom
and is configured such that it can control the rotational speed of
the indoor fan 43 and the outdoor fan 28, the rotational speed of
the compressor 21, and the like based on the detection signal, a
control signal from the remote controller, and the like.
[0047] Furthermore, prescribed threshold values are set in the
control unit 9 for the low pressure side pressure and the high
pressure side pressure detected by the refrigerant pressure sensor
33, and fluctuations, either upward or downward, in the low
pressure side pressure and the high pressure side pressure are
detected on the basis of these threshold values. Furthermore, this
detection makes it possible to know whether there is an abnormal
condition in any of the various equipment of the heating dedicated
air conditioner 1. For example, during a test operation in a test
operation mode, discussed below, when the gas side shutoff valve 27
is in not the open but the closed state, the pressure detected by
the refrigerant pressure sensor 33 falls below the threshold value
of the low pressure side pressure.
<Operation of Heating Dedicated Air Conditioner 1>
[0048] The principal operation Modes of the heating dedicated air
conditioner 1 are a normal operation mode, wherein the various
equipment of the outdoor unit 2 and the indoor unit 4 is controlled
in accordance with the operating load of the indoor unit 4, and the
test operation mode, which is for verifying, for example, whether
the various equipment of the outdoor unit 2 and the indoor unit 4
is operating normally, and whether the construction is correct
(e.g., whether the liquid side shutoff valve 26 and the gas side
shutoff valve 27 are in the open state). In the normal operation
mode, heating operation is principally performed. In the test
operation mode, test operation is performed. Furthermore, test
operation is performed after the installation of the various
equipment of the heating dedicated air conditioner 1 (specifically,
test operation is not limited to being performed after the initial
installation of the equipment, and may be performed, for example,
after making modifications such as adding or removing various
equipment of the outdoor unit 2 and the indoor unit 4, after
repairing an equipment failure, and the like).
[0049] The following text explains the operation of the heating
dedicated air conditioner 1 in each of the operation modes,
referencing FIG. 1. Furthermore, the operation of the heating
dedicated air conditioner 1 is performed by the control unit 9.
(1) Normal Operation Mode
(a) Heating Operation
[0050] First, heating operation in the normal operation mode will
be explained.
[0051] During heating operation, control is performed such that the
four-way switching valve 22 is in the first state. Namely, the
four-way switching valve 22 is controlled such that the state
obtains wherein the discharge side of the compressor 21 is
connected to the gas side of the indoor heat exchanger 42 via the
gas side shutoff valve 27 and the gas side refrigerant connection
pipe 7, and the suction side of the compressor 21 is connected to
the gas side of the outdoor heat exchanger 23.
[0052] Furthermore, in this state, if the compressor 21, the
outdoor fan 28, and the indoor fan 43 are driven, then the low
pressure gas refrigerant is suctioned into the compressor 21 and
therefore is compressed and transitions to high pressure gas
refrigerant. This high pressure gas refrigerant is delivered to the
indoor unit 4 via the four-way switching valve 22, the gas side
shutoff valve 27, and the gas side refrigerant connection pipe 7.
In the indoor heat exchanger 42, the heat of the high pressure gas
refrigerant delivered to the indoor unit 4 is exchanged with the
indoor air supplied by the indoor fan 43, and thereby that
refrigerant is condensed and transitions to high pressure liquid
refrigerant. The high pressure liquid refrigerant is delivered to
the outdoor unit 2 via the liquid side refrigerant connection pipe
6 and the liquid side shutoff valve 26. Furthermore, the pressure
of the high pressure liquid refrigerant delivered to the outdoor
unit 2 is reduced by the outdoor expansion valve 24, and that
refrigerant transitions to refrigerant in a low pressure gas-liquid
two-phase state and is delivered to the outdoor heat exchanger 23.
In the outdoor heat exchanger 23, the heat of the liquid
refrigerant in the low pressure gas-liquid two-phase state is
exchanged with the outdoor air supplied by the outdoor fan 28, and
thereby that refrigerant evaporates and transitions to low pressure
gas refrigerant. This low pressure gas refrigerant flows into the
accumulator 25 via the four-way switching valve 22 and then once
again is suctioned into the compressor 21.
[0053] Accordingly, the outdoor heat exchanger 23 functions as an
evaporator that evaporates the refrigerant. However, if the heating
operation of the heating dedicated air conditioner 1 is performed
under the condition wherein the temperature of the outdoor air,
which is the heat source of the outdoor heat exchanger 23, is low,
then one can assume that frost will adhere to the surface of the
outdoor heat exchanger. Furthermore, if frost does adhere to the
surface of the outdoor heat exchanger, then there is a risk that
the heat exchange performance of the outdoor heat exchanger will
decrease. Accordingly, in the heating dedicated air conditioner 1,
when frost adheres to the outdoor heat exchanger 23 during heating
operation, the four-way switching valve 22 is temporarily switched
from the first state to the second state and defrosting operation
is performed as below.
(b) Defrosting Operation
[0054] During defrosting operation, control is performed such that
the four-way switching valve 22 is in the second state. Namely, the
four-way switching valve 22 is controlled such that a state obtains
wherein the discharge side of the compressor 21 is connected to the
gas side of the outdoor heat exchanger 23, and the suction side of
the compressor 21 is connected to the gas side of the indoor heat
exchanger 42 via the gas side shutoff valve 27 and the gas side
refrigerant connection pipe 7.
[0055] In this state, if the compressor 21 is driven, first, the
low pressure gas refrigerant is suctioned into the compressor 21
where it is compressed and transitions to high pressure gas
refrigerant. Furthermore, the high pressure gas refrigerant is
delivered to the outdoor heat exchanger 23 via the four-way
switching valve 22, its heat is exchanged with the outdoor air in
the outdoor heat exchanger 23, and thereby condenses and
transitions to high pressure liquid refrigerant. At this time, the
frost or the ice that adheres to the surface of the outdoor heat
exchanger 23 melts owing to the heat emitted from the high pressure
gas refrigerant, which is undergoing the heat exchange process.
Furthermore, during defrosting operation, control is performed such
that the outdoor fan 28 is in the stopped state.
[0056] Furthermore, the outdoor expansion valve 24 reduces the
pressure of the high pressure liquid refrigerant, which transitions
to refrigerant in the low pressure gas-liquid two-phase state and
is delivered to the indoor unit 4 via the liquid side shutoff valve
26 and the liquid side refrigerant connection pipe 6. The
refrigerant in the low pressure gas-liquid two-phase state
delivered to the indoor unit 4 is then delivered to the indoor heat
exchanger 42; the heat of that refrigerant is exchanged with the
indoor air at the indoor heat exchanger 42, and thereby that
refrigerant evaporates and transitions to low pressure gas
refrigerant. At this time, the indoor fan 43 is controlled such
that it is in the stopped state. This is done in order to prevent
cold air from potentially being blown out into the indoor space
when the indoor fan 43 is operating, thereby reducing the comfort
of users of the indoor space.
[0057] Furthermore, the low pressure gas refrigerant is delivered
to the outdoor unit 2 via the gas side refrigerant connection pipe
7 and the gas side shutoff valve 27, and then flows into the
accumulator 25 via the four-way switching valve 22. Furthermore,
the low pressure liquid refrigerant that does not evaporate at the
indoor heat exchanger 42 because the indoor fan 43 is stopped
accumulates in the accumulator 25.
[0058] Furthermore, the low pressure gas refrigerant that flows
into the accumulator 25 is once again sucked into the compressor
21.
(2) Test Operation Mode
[0059] Test operation in the test operation mode will be explained
next. Note that test operation is performed by a worker operating
an operation button, which is provided to a remote controller (not
shown) and is for setting the operation mode to the test operation
mode. In addition, the test operation interval, which is the entire
interval during which test operation is performed in the test
operation mode, is set in advance (e.g., to three minutes);
[0060] furthermore, when the set test operation interval ends, the
mode switches to the operation mode set by the user via the remote
controller (i.e., to heating operation in the normal operation
mode).
[0061] Here, ordinarily, test operation is often performed in the
state wherein the four-way switching valve 22 is controlled such
that it is in the second state (i.e., when the refrigerant circuit
is in the so-called cooling cycle state). This is because if test
operation is performed during the heating cycle, then the pressure
detected by the refrigerant pressure sensor 33 will tend not to
rise, and consequently it could become difficult to promptly detect
whether the shutoff valve (e.g., the gas side shutoff valve 27) is
in the open state.
[0062] However, in a heating dedicated air conditioner, drainage
work, such as for discharging drain water accumulated in a drain
pan to the outdoor space, is often not undertaken. Consequently, if
the heating dedicated air conditioner is used and test operation is
performed during the cooling cycle in, for example, a high
temperature and high humidity location or during a high temperature
and high humidity season (e.g., summertime), then the refrigerant
that flows through the interior of an indoor heat exchanger will
take the heat of the indoor air delivered to the indoor heat
exchanger by an indoor fan, and thereby a large amount of drain
water is assumed to be generated in the indoor heat exchanger.
Therefore, even if the drain water generated in the indoor heat
exchanger could be accumulated in the drain pan, if the amount of
the drain water exceeds the capacity of the drain pan to store
water, then it is conceivable that the drain water will overflow
the drain pan and flow into the indoor space.
[0063] Accordingly, during test operation of the heating dedicated
air conditioner 1, drain water inhibition control, which operates
the compressor 21 and stops the indoor fan 43, is performed. A
drain water inhibited interval, during which drain water inhibition
control is performed, is the same as the test operation interval.
Namely, in the heating dedicated air conditioner 1, the indoor fan
43 is always stopped during test operation in the test operation
mode.
[0064] Thereby, the generation of drain water is inhibited because
the heat exchange efficiency between the refrigerant and the indoor
air in the indoor heat exchanger 42 is lower than when the indoor
fan 43 is being operated. Thereby, it is possible to prevent the
drain water from overflowing the drain pan 45.
[0065] Furthermore, the operation of the heating dedicated air
conditioner 1 during test operation is substantially the same as
the operation of the heating dedicated air conditioner 1 during
defrosting operation. However, during defrosting operation, the
outdoor fan 28 is stopped, whereas, during test operation, the
outdoor fan 28 is operated and the degree of opening of the outdoor
expansion valve 24 is fixed.
<Characteristics of Heating Dedicated Air Conditioner 1
According to the First Embodiment>
[0066] (1)
[0067] In the first embodiment, test operation is performed in the
state wherein the four-way switching valve 22 is in the second
state. Furthermore, during test operation, the indoor fan 43 is
stopped.
[0068] Thereby, the indoor fan 43 no longer delivers the indoor air
to the indoor heat exchanger 42, and therefore the amount of the
indoor air whose heat is exchanged with the refrigerant in the
indoor heat exchanger 42 decreases. Accordingly, because the drain
water generated in the indoor heat exchanger 42 also decreases, it
becomes possible to prevent the drain water from overflowing the
drain pan 45, even during the summer. In addition, because the
drain water does not overflow the drain pan 45, it is possible to
also prevent the drain water from flowing into the indoor space. In
addition, drain work also thereby becomes unnecessary.
(2)
[0069] In the first embodiment, the indoor fan 43 is stopped during
test operation and during defrosting operation. Consequently, the
amount of evaporation of the refrigerant flowing through the indoor
heat exchanger 42 is assumed to be less than when the indoor fan 43
is being operated. Furthermore, it is conceivable that the reduced
amount of evaporation of the refrigerant flowing through the indoor
heat exchanger 42 causes not only the gas refrigerant but also the
refrigerant in the gas-liquid two-phase state to flow out of the
indoor heat exchanger 42 and to the outdoor unit 2 side.
[0070] Accordingly, because the provision of the accumulator 25
between the suction side of the compressor 21 and the four-way
switching valve 22 makes it possible to accumulate the liquid
refrigerant in the accumulator 25 even if the refrigerant in the
gas-liquid two-phase state flows to the outdoor unit 2 side, it is
possible to cause the gas refrigerant alone to be suctioned to the
compressor 21. Thereby, it is possible to prevent damage to the
compressor 21.
<Modified Example of Heating Dedicated Air Conditioner 1
According to the First Embodiment>
[0071] The above text explained an embodiment of the present
invention based on the drawings, but the specific constitution is
not limited to that embodiment, and it is understood that
variations and modifications may be effected without departing from
the spirit and scope of the invention.
(A)
[0072] The abovementioned embodiment explained a case that is
limited to a separate type heating dedicated air conditioner 1,
wherein one indoor unit 4 is connected to one outdoor unit 2, but
the present invention is not limited thereto; for example, the
present invention may be adapted to an integrated type heating
dedicated air conditioner, wherein the outdoor unit 2 and the
indoor unit 4 are integrated.
[0073] In addition, the abovementioned embodiment explained a case
limited to a so-called paired heating dedicated air conditioner 1,
wherein one indoor unit 4 is connected to one outdoor unit 2, but
the present invention is not limited thereto. For example, the
present invention may be adapted to a so-called multi type heating
dedicated air conditioner, wherein a plurality of the indoor units
is connected to one outdoor unit 2.
(B)
[0074] In the abovementioned embodiment, the refrigerant is not
limited to fluorocarbon based refrigerant, and may be a natural
refrigerant such as CO.sub.2 refrigerant.
Second Embodiment
[0075] Continuing, a second embodiment of the heating dedicated air
conditioner 1 will now be explained. Note that components and the
like identical to those in the first embodiment are assigned the
same symbols, and explanations thereof are therefore omitted.
[0076] The second embodiment differs from the first embodiment as
follows: in the first embodiment, the indoor fan 43 is always
stopped during test operation in the test operation mode; however,
in the second embodiment, there is a case wherein the indoor fan 43
is operated, and is not always stopped, during test operation.
[0077] The text below explains the operation during test operation
of the heating dedicated air conditioner 1 in the second
embodiment, referencing FIG. 3.
[0078] FIG. 3 is a flow chart that illustrates operation during
test operation of the heating dedicated air conditioner 1 according
to the second embodiment.
[0079] First, in a step S101, the four-way switching valve 22 is
controlled such that it is in the second state, as in the first
embodiment. Furthermore, in a step S102, the compressor 21 and the
outdoor fan 28 are driven, as in the first embodiment. At this
time, in the first embodiment, the indoor fan 43 is always stopped
during test operation in the test operation mode, and consequently
the indoor fan 43 is not driven; however, in the second embodiment,
the indoor fan 43 is driven in addition to the compressor 21 and
the outdoor fan 28.
[0080] Next, in a step S103, it is determined whether the indoor
fan 43 is operating normally. If it is determined that it is
operating normally, then the process transitions to a step S104;
if, however, it is determined that it is not operating normally,
then the process transitions to a step S105.
[0081] In the step S104, drain water inhibition control is
performed, as in the first embodiment. Namely, the compressor 21
maintains its operation state as is, and the indoor fan 43
stops.
[0082] In the step S105, it has been determined that the indoor fan
43 is not operating normally, and therefore a warning is displayed
via a reporting unit (not shown; e.g., an LED or a character
display).
[0083] Accordingly, in the heating dedicated air conditioner 1
according to the second embodiment, the interval during which the
indoor fan 43 is driven (corresponding to a first interval) is
approximately 5-10 s. Thereby, the drain water inhibited interval,
which is the interval during which the drain water inhibition
control is performed, occupies 80% or more (specifically,
approximately 94%-97%) of the test operation interval (e.g., 3
minutes).
[0084] In addition, as discussed above, the interval during which
the indoor fan 43 is driven is the beginning interval in the test
operation interval. This is because drain water tends to be
generated if the indoor fan 43 is driven when the evaporation
temperature has fallen.
[0085] Furthermore, as in the indoor fan 43, a warning is displayed
even if the compressor 21, the outdoor fan 28, or the like is not
being driven normally.
<Characteristics of Heating Dedicated Air Conditioner 1
According to the Second Embodiment>
[0086] In the heating dedicated air conditioner 1 according to the
second embodiment, the indoor fan 43 can be driven during test
operation in the test operation mode, which is effective if, for
example, one wishes to verify whether the indoor fan 43 is
operating normally.
[0087] In addition, in the heating dedicated air conditioner 1
according to the second embodiment, the drain water inhibited
interval, which is the interval during which drain water inhibition
control is performed, occupies 80% or more of the test operation
interval.
[0088] During test operation in the test operation mode, it is
possible to reduce the amount of the indoor air delivered from the
indoor fan 43 to the indoor heat exchanger 42 by stopping the
indoor fan 43 for an interval that is 80% or more of the entire
interval. Thereby, the amount of drain water generated in the
indoor heat exchanger 42 decreases. Accordingly, even if the indoor
fan 43 is driven in order to verify whether the indoor fan 43 is
operating normally, it is still possible to prevent the drain water
from overflowing the drain pan 45.
[0089] In addition, in the heating dedicated air conditioner 1
according to the second embodiment, the interval during which the
indoor fan 43 is driven is the beginning interval in the test
operation interval. Namely, the indoor fan 43 is driven in the
beginning interval during test operation when the evaporation
temperature does not drop all that much. Thereby, it is possible to
prevent the drain water from overflowing the drain pan 45 even if
the indoor fan 43 is driven in order to verify whether the indoor
fan 43 is operating normally. In addition, drain work also thereby
becomes unnecessary.
<Modified Example of the Heating Dedicated Air Conditioner 1
According to the Second Embodiment>
[0090] In the abovementioned embodiments, the indoor fan 43 is
driven in order to verify whether it is operating normally, but the
present invention is not limited thereto; the indoor fan 43 may be
driven as discussed above for some other purpose. Even so, the same
effects as those discussed above are obtained.
INDUSTRIAL APPLICABILITY
[0091] In the present invention, if test operation of the heating
dedicated air conditioner is performed in the reverse cycle to that
of the heating cycle in, for example, summertime when the
temperature and humidity are high, then it is possible to prevent
drain water generated in the indoor heat exchanger from overflowing
the drain pan, thereby making drain work unnecessary, which is
useful.
REFERENCE SIGNS LIST
[0092] 1 Heating dedicated air conditioner [0093] 2 Outdoor casing
(outdoor unit) [0094] 4 Indoor casing (indoor unit) [0095] 7 Gas
side refrigerant connection pipe (gas refrigerant pipe) [0096] 9
Control unit [0097] 21 Compressor (compression mechanism) [0098] 22
Four-way switching valve [0099] 23 Outdoor heat exchanger [0100] 24
Outdoor expansion valve (expansion mechanism) [0101] 25 Accumulator
(gas-liquid separator) [0102] 27 Gas side shutoff valve [0103] 33
Refrigerant pressure sensor (pressure detector) [0104] 42 Indoor
heat exchanger [0105] 43 Indoor fan (fan)
CITATION LIST
Patent Literature
Patent Document 1
[0106] Japanese Unexamined Patent Application Publication No.
2001-99459
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