U.S. patent application number 13/256480 was filed with the patent office on 2012-01-12 for air conditioning apparatus.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. Invention is credited to Hidehiko Kinoshita, Tsuyoshi Yamada.
Application Number | 20120006040 13/256480 |
Document ID | / |
Family ID | 42739473 |
Filed Date | 2012-01-12 |
United States Patent
Application |
20120006040 |
Kind Code |
A1 |
Kinoshita; Hidehiko ; et
al. |
January 12, 2012 |
AIR CONDITIONING APPARATUS
Abstract
An air conditioning apparatus includes a refrigeration cycle, a
magnetic field generator, a detector and a control part. The
refrigeration cycle has a compression element, a refrigerant tube
in thermal contact with a refrigerant flowing through the
refrigerant tube and/or a heat-generating member in thermal contact
with a refrigerant flowing through the refrigerant tube. The
magnetic field generator generates a magnetic field to inductively
heat a heating target portion. The detector detects a state
quantity in a state quantity detection portion of the refrigeration
cycle. The control part performs startup magnetic field generation
control during startup of an air-warming operation in which maximum
magnetic field output is initiated until the state quantity
detected reaches a first target state quantity, and post-startup
magnetic field generation control in which the magnetic field
output is restricted after the startup magnetic field generation
control has ended.
Inventors: |
Kinoshita; Hidehiko; (
Osaka, JP) ; Yamada; Tsuyoshi; ( Osaka, JP) |
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
42739473 |
Appl. No.: |
13/256480 |
Filed: |
March 18, 2010 |
PCT Filed: |
March 18, 2010 |
PCT NO: |
PCT/JP2010/001942 |
371 Date: |
September 14, 2011 |
Current U.S.
Class: |
62/151 ;
62/228.1 |
Current CPC
Class: |
F25B 47/022 20130101;
F25B 2400/01 20130101; F25B 2313/02741 20130101; F25B 2313/008
20130101; F25B 2313/0315 20130101; F25B 2500/26 20130101; F25B
13/00 20130101; F25B 2313/0314 20130101; F25B 2313/0312
20130101 |
Class at
Publication: |
62/151 ;
62/228.1 |
International
Class: |
F25B 49/02 20060101
F25B049/02; F25D 21/06 20060101 F25D021/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2009 |
JP |
2009-069132 |
Claims
1. An air conditioning apparatus comprising: a refrigeration cycle
having a compression element configured to circulate refrigerant, a
refrigeration tube arranged to make thermal contact with a
refrigerant flowing through the refrigerant tube and/or a
heat-generating member arranged to make thermal contact with a
refrigerant flowing through the refrigerant tube; a magnetic field
generator arranged to generate a magnetic field in order to
inductively heat a heating target portion; a refrigerant state
quantity detector arranged and configured to detect a state
quantity relating to refrigerant flowing through a predetermined
state quantity detection portion which is at least part of the
refrigeration cycle; and a control part configured to perform
startup magnetic field generation control during startup involving
performing an air-warming operation in the refrigeration cycle, a
state in which output of the magnetic field generator is a
predetermined maximum output being initiated from a time the
compression element has assumed a drive state and is ended when the
state quantity detected by the refrigerant state quantity detector
reaches a first predetermined target state quantity, and
post-startup magnetic field generation control in which a state
involving applying of a restriction that a first magnetic field
limit reference value lower than the predetermined maximum output
is an upper limit of the output of the magnetic field generator is
performed after the startup magnetic field generation control has
ended.
2. The air conditioning apparatus according to claim 1, wherein the
heating target portion contains a magnetic material.
3. The air conditioning apparatus according to claim 1, wherein the
predetermined state quantity detection portion is a portion in
which a magnetic field is generated by the magnetic field
generator.
4. The air conditioning apparatus according to claim 1, wherein the
state quantity detected by the refrigerant state quantity detector
includes at least one temperature and pressure relating to the
refrigerant flowing through the predetermined state quantity
detection portion.
5. The air conditioning apparatus according to claim 1, wherein the
refrigerant state quantity detector is a temperature detector
arranged and configured to detect a temperature relating to the
refrigerant flowing through the predetermined state quantity
detection portion; and in the post-startup magnetic field
generation control, the control part is further configured to
perform post-startup magnetic field generation PI control in order
to PI control a size of the magnetic field generated by the
magnetic field generator and/or a frequency with which the magnetic
field generator generates a magnetic field so that the temperature
detected by the temperature detector is maintained at a target
maintenance temperature.
6. The air conditioning apparatus according to claim 1, wherein the
refrigerant state quantity detector is a temperature detector
arranged and configured to detect a temperature relating to the
refrigerant flowing through the predetermined state quantity
detection portion; and the control part is further configured to
execute the startup magnetic field generation control after
fulfilling of a magnetic field level increase condition that there
be a change in the detected temperature of the temperature
detector, or that the temperature detector detect a temperature
change, due to a magnetic field level change process being
performed in order to raise or lower a level of the magnetic field
generated by the magnetic field generator within a range below the
predetermined maximum output.
7. The air conditioning apparatus according to claim 6; wherein a
maximum magnetic field level outputted in the magnetic field level
change process is a value less than the first magnetic field limit
reference value.
8. The air conditioning apparatus according to claim 1; wherein the
refrigerant state quantity detector is a temperature detector
arranged and configured to detect a temperature relating to the
refrigerant flowing through the predetermined state quantity
detection portion; and the control part is further configured to
execute a determination of a magnetic field level increase
condition after the fulfilling of a flow condition that there be a
change in the detected temperature of the temperature detector
between a first compression element state and a second compression
element state, when the compression element is caused to realize
two compression element states of different compression element
outputs, one being the first compression mechanism state and the
other being the second compression element state having a higher
output level than the first compression element state.
9. The air conditioning apparatus according to claim 1; wherein the
refrigerant state quantity detector is a temperature detector
arranged and configured to detect a temperature relating to the
refrigerant flowing through the predetermined state quantity
detection portion; and the control part is further configured to
perform a defrosting operation output control in order to control
the output of the magnetic field generator based on the detected
temperature of the temperature detector, the upper limit of the
output of the magnetic field generator being the predetermined
maximum output, when the refrigeration cycle executes a defrosting
operation different from the air-warming operation after the
post-startup magnetic field generation control has been
initiated.
10. The air conditioning apparatus according to claim 9; wherein
during the defrosting operation output control, the control part is
further configured to perform defrosting PI control in which PI
control is performed so that the temperature detected by the
temperature detector is maintained at a second predetermined target
temperature that is lower than the first predetermined target
temperature.
11. The air conditioning apparatus according to claim 1; wherein
the refrigerant state quantity detector is a temperature detector
arranged and configured to detect a temperature relating to the
refrigerant flowing through the predetermined state quantity
detection portion; and the air conditioning apparatus further
comprises an elastic member arranged to apply an elastic force to
the temperature detector, the temperature detector being pressed
against the predetermined state quantity detection portion by the
elastic force of the elastic member when applied.
12. The air conditioning apparatus according to claim 2, wherein
the predetermined state quantity detection portion is a portion in
which a magnetic field is generated by the magnetic field
generator.
13. The air conditioning apparatus according claim 12, wherein the
state quantity detected by the refrigerant state quantity detector
includes at least one temperature and pressure relating to the
refrigerant flowing through the predetermined state quantity
detection portion.
14. The air conditioning apparatus according claim 2, wherein the
state quantity detected by the refrigerant state quantity detector
includes at least one temperature and pressure relating to the
refrigerant flowing through the predetermined state quantity
detection portion.
15. The air conditioning apparatus according claim 3, wherein the
state quantity detected by the refrigerant state quantity detector
includes at least one temperature and pressure relating to the
refrigerant flowing through the predetermined state quantity
detection portion.
Description
TECHNICAL FIELD
[0001] The present invention relates to an air conditioning
apparatus.
BACKGROUND ART
[0002] Among air conditioning apparatuses capable of an air-warming
operation, there have been those proposed which include a
refrigerant heating function intended to increase air-warming
capability.
[0003] For example, in the air conditioning apparatus disclosed in
Patent Literature 1 shown below (Japanese Laid-open Patent
Application Publication No. 2000-97510), the air-warming capability
is increased due to the refrigerant flowing into a refrigerant
heating device and being heated by a gas burner.
[0004] In the air conditioning apparatus disclosed in Patent
Literature 1 (Japanese Laid-open Patent Application Publication No.
2000-97510), a technique is proposed in which the combustion rate
of the gas burner is adjusted based on the detection value of a
thermistor, in order to prevent the refrigerant temperature from
rising too high and protective action from being taken too
frequently during the air-warming operation.
SUMMARY OF THE INVENTION
Technical Problem
[0005] In the technique disclosed in the aforementioned Patent
Literature 1, only the frequency of the protective action is
suppressed, and no control is proposed to address the difference in
loads between during startup and after startup.
[0006] For example, in some cases, there is a large difference
between the surrounding temperature and the set temperature at the
startup of the air conditioning apparatus and the set temperature
is desired to be quickly reached, while there is also a difference
in loads between during startup and after startup, in which case
there is a risk of overshooting in which the target value is far
exceeded.
[0007] When the system for heating the refrigerant is an
electromagnetic induction heating system, the aforementioned
overshooting in particular is likely to be a problem because of the
high heating rate.
[0008] The present invention was devised in view of the
circumstances described above, and an object thereof is to provide
an air conditioning apparatus capable of quickly ensuring
performance at startup and keeping post-startup overshooting to a
minimum.
Solution to Problem
[0009] An air conditioning apparatus according to a first aspect is
an air conditioning apparatus which uses a refrigeration cycle
having a compression mechanism for circulating refrigerant, a
refrigeration tube that makes thermal contact with the refrigerant
flowing through the refrigerant tube and/or a heat-generating
member that makes thermal contact with the refrigerant flowing
through the refrigerant tube; the air conditioning apparatus
comprising a magnetic field generator, a refrigerant state quantity
detector, and a control part. The magnetic field generator
generates a magnetic field for induction-heating a portion to be
heated by induction heating. The refrigerant state quantity
detector detects a state quantity relating to refrigerant flowing
through a predetermined state quantity detected portion which is at
least part of the refrigeration cycle. The state quantity in this
instance includes at least one of, e.g., the temperature and the
pressure. The control part performs startup magnetic field
generation control and post-startup magnetic field generation
control. In startup magnetic field generation control, during
startup involving performing an air-warming operation in the
refrigeration cycle, the control part initiates a state in which
the output of the magnetic field generator is a predetermined
maximum output from the time the compression mechanism has assumed
a drive state, and ends this state when the state quantity detected
by the refrigerant state quantity detector reaches a first
predetermined target state quantity. In post-startup magnetic field
generation control, after the startup magnetic field generation
control has ended, the control part performs a state of applying a
restriction that a first magnetic field limit reference value lower
than the predetermined maximum output be an upper limit of the
output of the magnetic field generator. The phrase "when the
refrigeration cycle is performing the air-warming operation" herein
does not include operations such as a defrosting operation. The
heating by the electromagnetic induction heating unit herein
includes at least, e.g., electromagnetic induction heating of a
heat-generating member in thermal contact with the refrigerant
tube, electromagnetic induction heating of a heat-generating member
in thermal contact with the refrigerant flowing through the
refrigerant tube, and electromagnetic induction heating of a
heat-generating member constituting at least part of the
refrigerant tube.
[0010] In the air conditioning apparatus according to the aspect
described above, by performing startup magnetic field generation
control so that the output of the magnetic field generator during
startup reaches a maximum, the time needed for warm air to be
provided to the user after initiating the air-warming operation
startup can be shortened. It is also possible to minimize control
overshooting caused by the output of the magnetic field generator
being raised too high during post-startup magnetic field generation
control. It is thereby possible for control overshooting to be
minimized, while the supply of warm air to the user is quickly
started.
[0011] An air conditioning apparatus according to a second aspect
is the air conditioning apparatus of the first aspect, wherein the
portion to be heated by induction heating includes a magnetic
material.
[0012] In the air conditioning apparatus according to the aspect
described above, since the magnetic field generator generates a
magnetic field using the portion containing the magnetic material
as a target, heat generation by electromagnetic induction can be
performed efficiently.
[0013] An air conditioning apparatus according to a third aspect is
the air conditioning apparatus according to the first or second
aspect, wherein the predetermined state quantity detection portion
is a portion in which a magnetic field is generated by the magnetic
field generator.
[0014] In the air conditioning apparatus according to the aspect
described above, since rapid temperature changes caused by
electromagnetic induction heating can be perceived, control
responsiveness can be improved.
[0015] An air conditioning apparatus according to a fourth aspect
is the air conditioning apparatus according to any of the first
through third aspects, wherein the state quantity detected by the
refrigerant state quantity detector includes at least one of either
the temperature or pressure relating to the refrigerant flowing
through the predetermined state quantity detection portion.
[0016] In the air conditioning apparatus according to the aspect
described above, various sensors used in order to control the state
of the refrigeration cycle can be used to perform the detections
herein.
[0017] An air conditioning apparatus according to a fifth aspect is
the air conditioning apparatus according to any of the first
through fourth aspects, wherein the refrigerant state quantity
detector is a temperature detector for detecting a temperature
relating to the refrigerant flowing through the predetermined state
quantity detection portion. In the post-startup magnetic field
generation control, the control part performs post-startup magnetic
field generation PI control for performing PI control of the value
or frequency relating to the output of the magnetic field generator
so that the temperature detected by the temperature detector is
maintained at a target maintenance temperature. The target
maintenance temperature herein may be the same temperature as the
first predetermined target temperature.
[0018] In the air conditioning apparatus according to the aspect
described above, temperature changes caused by electromagnetic
induction heating are commonly more sudden than temperature changes
resulting from changes in the state of the refrigerant passing
through the predetermined state quantity detection portion. Even
when the temperature suddenly changes due to electromagnetic
induction heating in this manner, the temperature detected by the
temperature detector can be stabilized at the second predetermined
target temperature by PI-controlling the size of the magnetic field
generated by the magnetic field generator and/or the frequency with
which the magnetic field generator generates a magnetic field.
[0019] An air conditioning apparatus according to a sixth aspect is
the air conditioning apparatus according to any of the first
through fifth aspects, wherein the refrigerant state quantity
detector is a temperature detector for detecting a temperature
relating to the refrigerant flowing through the predetermined state
quantity detection portion. The control part executes the startup
magnetic field generation control after a magnetic field level
increase condition has been fulfilled. This magnetic field level
increase condition is that there be a change in the detected
temperature of the temperature detector or that the temperature
detector detect a temperature change, due to a magnetic field level
change process being performed for raising or lowering the level of
the magnetic field generated by the magnetic field generator within
a range below the predetermined maximum output.
[0020] When the temperature detector is unable to detect a
temperature change even though electromagnetic induction heating
has been performed, there is a risk of the state of attachment of
the temperature detector becoming unstable or coming apart.
[0021] As a countermeasure to this, in the air conditioning
apparatus according to the aspect described above, when the state
of attachment of the temperature detector becomes unstable or comes
apart in this manner, the temperature change is insufficient and
the magnetic field level increase condition is not fulfilled.
Therefore, the control part limits magnetic field generation to a
level lower than the predetermined maximum output and does not
perform magnetic field generation at a high level, and the
reliability of the device can therefore be improved. When the
magnetic field level increase condition has been fulfilled, it is
possible to perceive that the portion to be heated by induction
heating is generating heat due to the generation of a magnetic
field by the magnetic field generator, the installed state of the
temperature detector is satisfactory, and the temperature of the
heating target portion of induction heating is successfully and
accurately confirmed. It is thereby possible to suppress damage to
the devices caused by abnormal temperature increases from
electromagnetic induction heating, and to improve the reliability
of the devices.
[0022] An air conditioning apparatus according to a seventh aspect
is the air conditioning apparatus of the sixth aspect, wherein a
maximum magnetic field level outputted in the magnetic field level
change process is a value less than the first magnetic field limit
reference value.
[0023] In the air conditioning apparatus according to the aspect
described above, it is possible to prevent electromagnetic
induction heating caused by a magnetic field of a size
approximately equivalent to the first magnetic field limit
reference value in stages in which the state of attachment of the
temperature detector has not yet been confirmed to be
satisfactory.
[0024] An air conditioning apparatus according to an eighth aspect
is the air conditioning apparatus according to any of the first
through seventh aspects, wherein the refrigerant state quantity
detector is a temperature detector for detecting a temperature
relating to the refrigerant flowing through the predetermined state
quantity detection portion. The control part executes determining
of the magnetic field level increase condition after a flow
condition has been fulfilled. The flow condition is that there be a
change in the detected temperature of the temperature detector
between a first compression mechanism state and a second
compression mechanism state, when the compression mechanism is
caused to realize two compression mechanism states of different
compression mechanism outputs, one being the first compression
mechanism state and the other being the second compression
mechanism state having a higher output level than the first
compression mechanism state. A state in which the compression
mechanism is stopped is included in the first compression mechanism
state.
[0025] In the air conditioning apparatus according to the aspect
described above, there is a risk of the flow of refrigerant being
insufficient when the flow condition is not fulfilled, and there is
a risk of causing an abnormal temperature increase even with a
magnetic field generator output at the level for determining the
magnetic field level increase condition. As a countermeasure to
this, In the air conditioning apparatus according to the aspect
described above, since the magnetic field level increase condition
can be determined while ensuring a flow of refrigerant passing
through the predetermined state quantity detection portion, a
determination of the magnetic field level increase condition can be
performed while maintaining the reliability of the devices.
[0026] An air conditioning apparatus according to a ninth aspect is
the air conditioning apparatus according to any of the first
through eighth aspects, wherein the refrigerant state quantity
detector is a temperature detector for detecting a temperature
relating to the refrigerant flowing through the predetermined state
quantity detection portion. The control part performs a defrosting
operation output control for controlling the output of the magnetic
field generator on the basis of the detected temperature of the
temperature detector, the upper limit of the output of the magnetic
field generator being the predetermined maximum output, when the
refrigeration cycle executes a defrosting operation different from
the air-warming operation after the post-startup magnetic field
generation control has been initiated.
[0027] In the air conditioning apparatus according to the aspect
described above, since the output of the magnetic field generator
can be increased similarly with respect to the startup magnetic
field generation control, the defrosting process can be
quickened.
[0028] An air conditioning apparatus according to a tenth aspect is
the air conditioning apparatus of the ninth aspect, wherein during
the defrosting operation output control, the control part performs
defrosting PI control in which PI control is performed so that the
temperature detected by the temperature detector is maintained at a
second predetermined target temperature that is lower than the
first predetermined target temperature.
[0029] In the air conditioning apparatus according to the aspect
described above, since abnormal increases in temperature do not
occur readily during the defrosting operation compared to when
startup magnetic field generation control is performed,
overshooting during the defrosting operation can be reduced by
using the detected temperature of the temperature detector as the
second predetermined target temperature below the first
predetermined target temperature of the startup magnetic field
generation control.
[0030] An air conditioning apparatus according to an eleventh
aspect is the air conditioning apparatus of any of the first
through tenth aspects, wherein the refrigerant state quantity
detector is a temperature detector for detecting a temperature
relating to the refrigerant flowing through the predetermined state
quantity detection portion. The air conditioning apparatus further
comprises an elastic member for applying elastic force to the
temperature detector. The temperature detector is pressed against
the predetermined state quantity detection portion by the elastic
force of the elastic member.
[0031] In the air conditioning apparatus according to the aspect
described above, it is common for sudden temperature increases to
occur more readily when electromagnetic induction heating is
performed than temperature increases caused by changes in the
refrigerant circulating condition in the refrigeration cycle.
[0032] As a countermeasure to this, in the air conditioning
apparatus according to the aspect described above, since the
temperature detector is kept pressed against the predetermined
state quantity detecting portion by the elastic member, the
responsiveness of the temperature detector can be improved.
Thereby, control with improved responsiveness can be performed.
Advantageous Effects of Invention
[0033] In the air conditioning apparatus according to the first
aspect, control overshooting can be kept to a minimum while the
supply of warm air to the user is quickly initiated.
[0034] In the air conditioning apparatus according to the second
aspect, heat generation by electromagnetic induction can be
performed efficiently.
[0035] In the air conditioning apparatus according to the third
aspect, control responsiveness can be improved.
[0036] In the air conditioning apparatus according to the fourth
aspect, various sensors used in order to control the state of the
refrigeration cycle can be used to perform the detections
herein.
[0037] In the air conditioning apparatus according to the fifth
aspect, the temperature detected by the temperature detector can be
stabilized at the second predetermined target temperature.
[0038] In the air conditioning apparatus according to the sixth
aspect, it is possible to suppress damage to the devices caused by
abnormal temperature increases from electromagnetic induction
heating, and the reliability of the devices can be improved.
[0039] In the air conditioning apparatus according to the seventh
aspect, it is possible to prevent electromagnetic induction heating
caused by a magnetic field at approximately the size of the first
magnetic field limit reference value in stages in which the state
of attachment of the temperature detector has not yet been
confirmed to be satisfactory.
[0040] In the air conditioning apparatus according to the eighth
aspect, a determination of the magnetic field level increase
condition can be performed while the reliability of the devices is
preserved.
[0041] In the air conditioning apparatus according to the ninth
aspect, the defrosting process can be quickened.
[0042] In the air conditioning apparatus according to the tenth
aspect, overshooting during the defrosting operation can be
reduced.
[0043] In the air conditioning apparatus according to the eleventh
aspect, control with improved responsiveness can be performed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a refrigerant circuit diagram of an air
conditioning apparatus according to an embodiment of the present
invention.
[0045] FIG. 2 is an external perspective view including the front
side of an outdoor unit.
[0046] FIG. 3 is a perspective view of the internal arrangement and
configuration of the outdoor unit.
[0047] FIG. 4 is an external perspective view including the rear
side of the internal arrangement and configuration of the outdoor
unit.
[0048] FIG. 5 is an overall front perspective view showing the
internal structure of a machine chamber of the outdoor unit.
[0049] FIG. 6 is a perspective view showing the internal structure
of the machine chamber of the outdoor unit.
[0050] FIG. 7 is a perspective view of a bottom plate and an
outdoor heat exchanger of the outdoor unit.
[0051] FIG. 8 is a plan view in which an air-blowing mechanism of
the outdoor unit has been removed.
[0052] FIG. 9 is a plan view showing the arrangement relationship
between the bottom plate of the outdoor unit and the hot gas bypass
circuit.
[0053] FIG. 10 is an external perspective view of an
electromagnetic induction heating unit.
[0054] FIG. 11 is an external perspective view showing a state in
which a shielding cover has been removed from the electromagnetic
induction heating unit.
[0055] FIG. 12 is an external perspective view of an
electromagnetic induction thermistor.
[0056] FIG. 13 is an external perspective view of a fuse.
[0057] FIG. 14 is a schematic cross-sectional view showing the
state of attachment of the electromagnetic induction thermistor and
the fuse.
[0058] FIG. 15 is a cross-sectional structural view of the
electromagnetic induction heating unit.
[0059] FIG. 16 is a view showing a time chart of electromagnetic
induction heating control.
[0060] FIG. 17 is a view showing a flowchart of a flow condition
judgment process.
[0061] FIG. 18 is a view showing a flowchart of a sensor-separation
detection process.
[0062] FIG. 19 is a view showing a flowchart of a rapid
pressure-increasing process.
[0063] FIG. 20 is a view showing a flowchart of a steady output
process.
[0064] FIG. 21 is a view showing a flowchart of a defrosting
process.
[0065] FIG. 22 is a view showing the attached position of an
electromagnetic induction thermistor according to another
embodiment (A).
[0066] FIG. 23 is an illustrative view of a refrigerant tube of
another embodiment (F).
[0067] FIG. 24 is an illustrative view of a refrigerant tube of
another embodiment (G).
[0068] FIG. 25 is a view showing an example of arranging coils and
a refrigerant tube of another embodiment (H).
[0069] FIG. 26 is a view showing an example of arranging bobbin
covers of another embodiment (H).
[0070] FIG. 27 is a view showing an example of arranging ferrite
cases of another embodiment (H).
DESCRIPTION OF EMBODIMENTS
[0071] An air conditioning apparatus 1 comprising an
electromagnetic induction heating unit 6 in one embodiment of the
present invention is described in an example hereinbelow with
reference to the drawings.
[0072] <1-1> Air Conditioning Apparatus 1
[0073] FIG. 1 shows a refrigerant circuit diagram showing a
refrigerant circuit 10 of the air conditioning apparatus 1.
[0074] In the air conditioning apparatus 1, an outdoor unit 2 as a
heat source-side apparatus and an indoor unit 4 as a usage-side
apparatus are connected by refrigerant tubes, and air conditioning
is performed in the space where the usage-side apparatus is
located; the air conditioning apparatus 1 comprising a compressor
21, a four-way switching valve 22, an outdoor heat exchanger 23, an
outdoor electric expansion valve 24, an accumulator 25, outdoor
fans 26, an indoor heat exchanger 41, an indoor fan 42, a hot gas
bypass valve 27, a capillary tube 28, an electromagnetic induction
heating unit 6, and other components.
[0075] The compressor 21, the four-way switching valve 22, the
outdoor heat exchanger 23, the outdoor electric expansion valve 24,
the accumulator 25, the outdoor fans 26, the hot gas bypass valve
27, the capillary tube 28, and the electromagnetic induction
heating unit 6 are housed within the outdoor unit 2. The indoor
heat exchanger 41 and the indoor fan 42 are housed within the
indoor unit 4.
[0076] The refrigerant circuit 10 has a discharge tube A, an
indoor-side gas tube B, an indoor-side liquid tube C, an
outdoor-side liquid tube D, an outdoor-side gas tube E, an
accumulation tube F, an intake tube G, a hot gas bypass circuit H,
a branched tube K, and a converging tube J. Large quantities of
gas-state refrigerant pass through the indoor-side gas tube B and
the outdoor-side gas tube E, but the refrigerant passing through is
not limited to a gas refrigerant. Large quantities of liquid-state
refrigerant pass through the indoor-side liquid tube C and the
outdoor-side liquid tube D, but the refrigerant passing through is
not limited to a liquid refrigerant.
[0077] The discharge tube A is connected with the compressor 21 and
the four-way switching valve 22.
[0078] The indoor-side gas tube B connects the four-way switching
valve 22 and the indoor heat exchanger 41. A pressure sensor 29a
for sensing the pressure of the refrigerant passing through is
provided at some point along the indoor-side gas tube B.
[0079] The indoor-side liquid tube C connects the indoor heat
exchanger 41 and the outdoor electric expansion valve 24.
[0080] The outdoor-side liquid tube D connects the outdoor electric
expansion valve 24 and the outdoor heat exchanger 23.
[0081] The outdoor-side gas tube E connects the outdoor heat
exchanger 23 and the four-way switching valve 22.
[0082] The accumulation tube F connects the four-way switching
valve 22 and the accumulator 25, and extends in a vertical
direction when the outdoor unit 2 has been installed. The
electromagnetic induction heating unit 6 is attached to a part of
the accumulation tube F. A heat-generating portion of the
accumulation tube F, whose periphery is covered at least by a coil
68 described hereinafter, is composed of a copper tube F1 through
which refrigerant flows and a magnetic tube F2 provided so as to
cover the periphery of the copper tube F1 (see FIG. 15). This
magnetic tube F2 is composed of SUS (stainless used steel) 430.
This SUS 430 is a ferromagnetic material, which creates eddy
currents when placed in a magnetic field and which generates heat
by Joule heat created by its own electrical resistance. Aside from
the magnetic tube F2, the tubes constituting the refrigerant
circuit 10 are composed of copper tubes, the same material as the
copper tube F1. The material of the tubes covering the peripheries
of these copper tubes is not limited to SUS 430; it can be, for
example, iron, copper, aluminum, chrome, nickel, other conductors,
and alloys containing at least two or more metals selected from
these listed. Possible examples of the magnetic material include
ferrite, martensite, or a combination thereof, but it is preferable
to use a ferromagnetic substance which has a comparatively high
electrical resistance and which has a higher Curie temperature than
its service temperature range. The accumulation tube F here
requires more electricity, but may not comprise a magnetic
substance and a material containing a magnetic substance, or may
include a material that will be the target of induction heating.
The magnetic material may constitute the entire accumulation tube
F, it may be formed only in the inside surface of the accumulation
tube F, or it may be present due to being included in the material
constituting the accumulation tube F, for example. By performing
electromagnetic induction heating in this manner, the accumulation
tube F can be heated by electromagnetic induction, and the
refrigerant drawn into the compressor 21 via the accumulator 25 can
be warmed. The warming capability of the air conditioning apparatus
1 can thereby be improved. Even in cases in which the compressor 21
is not sufficiently warmed at the startup of the air-warming
operation, for example, the lack of capability at startup can be
compensated for by the quick heating by the electromagnetic
induction heating unit 6. Furthermore, when the four-way switching
valve 22 is switched to the air-cooling operation state and a
defrosting operation is performed for removing frost deposited on
the outdoor heat exchanger 23 or other components, the compressor
21 can quickly compress the warmed refrigerant due to the
electromagnetic induction heating unit 6 quickly heating the
accumulation tube F. Therefore, the temperature of the hot gas
discharged from the compressor 21 can be quickly increased. The
time required to thaw the frost through the defrosting operation
can thereby be shortened. Thereby, even when the defrosting
operation must be performed at the right time during the
air-warming operation, a return to the air-warming operation can be
made as quickly as possible, and user comfort can be improved.
[0083] The intake tube G connects the accumulator 25 and the intake
side of the compressor 21.
[0084] The hot gas bypass circuit H connects a branching point A1
provided at some point along the discharge tube A and a branching
point D1 provided at some point along the outdoor-side liquid tube
D. Disposed at some point in the hot gas bypass circuit H is the
hot gas bypass valve 27, which can switch between a state of
permitting the passage of refrigerant and a state of not permitting
the passage of refrigerant. Between the hot gas bypass valve 27 and
the branching point D1, the hot gas bypass circuit H is provided
with a capillary tube 28 for lowering the pressure of refrigerant
passing through. This capillary tube 28 makes it possible to
approach the pressure that follows the refrigerant pressure
decrease by the outdoor electric expansion valve 24 during the
air-warming operation, and therefore makes it possible to suppress
the rise in refrigerant pressure in the outdoor-side liquid tube D
caused by the supply of hot gas through the hot gas bypass circuit
H to the outdoor-side liquid tube D.
[0085] The branched tube K, which constitutes part of the outdoor
heat exchanger 23, consists of a refrigerant tube extending from a
gas-side inlet/outlet 23e of the outdoor heat exchanger 23 and
branching into a plurality of tubes at a branching/converging point
23k described hereinafter, in order to increase the effective
surface area for heat exchange. The branched tube K has a first
branched tube K1, a second branched tube K2, and a third branched
tube K3 which extend independently from the branching/converging
point 23k to a converging/branching point 23j, and these branching
tubes K1, K2, K3 converge at the converging/branching point 23j.
Seen from the side with the converging tube J, the branched tube K
branches at and extends from the converging/branching point
23j.
[0086] The converging tube J, which constitutes a part of the
outdoor heat exchanger 23, is a tube extending from the
converging/branching point 23j to a liquid-side inlet/outlet 23d of
the outdoor heat exchanger 23. The converging tube J is capable of
equalizing the subcooling degree of the refrigerant flowing out
from the outdoor heat exchanger 23 during the air-cooling
operation, and is also capable of thawing ice deposited in the
vicinity of the lower end of the outdoor heat exchanger 23 during
the air-warming operation. The converging tube J has a
cross-sectional area approximately three times each of those of the
branching tubes K1, K2, K3, and the amount of refrigerant passing
through is approximately three times greater than in each of the
branching tubes K1, K2, K3.
[0087] The four-way switching valve 22 is capable of switching
between an air-cooling operation cycle and an air-warming operation
cycle. In FIG. 1, the connection state during the air-warming
operation is shown by solid lines, and the connection state during
the air-cooling operation is shown by dotted lines. During the
air-warming operation, the indoor heat exchanger 41 functions as a
cooler of refrigerant and the outdoor heat exchanger 23 functions
as a heater of refrigerant. During the air-cooling operation, the
outdoor heat exchanger 23 functions as a cooler of refrigerant and
the indoor heat exchanger 41 functions as a heater of
refrigerant.
[0088] The outdoor heat exchanger 23 has the gas-side inlet/outlet
23e, the liquid-side inlet/outlet 23d, the branching/converging
point 23k, the converging/branching point 23j, the branched tube K,
the converging tube J, and heat exchange fins 23z. The gas-side
inlet/outlet 23e is positioned in the end of the outdoor heat
exchanger 23 next to the outdoor-side gas tube E, and is connected
to the outdoor-side gas tube E. The liquid-side inlet/outlet 23d is
positioned in the end of the outdoor heat exchanger 23 next to the
outdoor-side liquid tube D, and is connected to the outdoor-side
liquid tube D. The branching/converging point 23k is where the tube
extending from the gas-side inlet/outlet 23e branches, and the
refrigerant can branch or converge depending on the direction in
which the refrigerant is flowing. The branched tube K extends as a
plurality of tubes from each of the branched portions in the
branching/converging point 23k. The converging/branching point 23j
is where the branched tube K converges, and the refrigerant can
converge or branch depending on the direction in which the
refrigerant is flowing. The converging tube J extends from the
converging/branching point 23j to the liquid-side inlet/outlet 23d.
The heat exchange fins 23z are composed of a plurality of
plate-shaped aluminum fins aligned in their plate-thickness
direction and arranged at predetermined intervals. The branched
tube K and the converging tube J both pass through the heat
exchange fins 23z. Specifically, the branched tube K and the
converging tube J are arranged so as to penetrate in the
plate-thickness direction through different parts of the same heat
exchange fins 23z. Upwind side of the outdoor fans 26 in the
direction of air flow, the outdoor heat exchanger 23 is provided
with an outdoor air temperature sensor 29b for sensing the
temperature of the outdoor air. The outdoor heat exchanger 23 is
also provided with an outdoor heat exchange temperature sensor 29c
for sensing the temperature of the refrigerant flowing through the
branched tube air conditioning apparatus.
[0089] An indoor temperature sensor 43 for sensing the indoor
temperature is provided inside the indoor unit 4. The indoor heat
exchanger 41 is also provided with an indoor heat exchange
temperature sensor 44 for sensing the refrigerant temperature of
the side next to the indoor-side liquid tube C where the outdoor
electric expansion valve 24 is connected.
[0090] An outdoor control part 12 for controlling the devices
disposed in the outdoor unit 2 and an indoor control part 13 for
controlling the devices disposed in the indoor unit 4 are connected
by a communication line 11 a, thereby constituting a control part
11. This control part 11 performs various controls on the air
conditioning apparatus 1.
[0091] The outdoor control part 12 is also provided with a timer 95
for counting the elapsed time when the various controls are
performed.
[0092] A controller 90 for receiving a setting input from the user
is connected to the control part 11.
[0093] <1-2> Outdoor Unit 2
[0094] FIG. 2 shows an external perspective view of the front side
of the outdoor unit 2. FIG. 3 shows a perspective view depicting
the positional relationship between the outdoor heat exchanger 23
and the outdoor fans 26. FIG. 4 shows a perspective view of the
rear side of the outdoor heat exchanger 23.
[0095] The outside surfaces of the outdoor unit 2 are configured
from a substantially rectangular parallelepiped outdoor unit
casing, which is configured from a ceiling plate 2a, a bottom plate
2b, a front panel 2c, a left side panel 2d, a right side panel 2f,
and a rear side panel 2e.
[0096] The outdoor unit 2 is sectioned via a partitioning plate 2H
into an air-blower chamber next to the left side panel 2d, in which
the outdoor heat exchanger 23, the outdoor fans 26, and other
components are placed; and a machine chamber next to the right side
panel 2f, where the compressor 21 and/or the electromagnetic
induction heating unit 6 are placed. The outdoor unit 2 is fixed in
place by being screwed onto the bottom plate 2b, and the outdoor
unit 2 has an outdoor unit support stand 2G constituting the left
and right sides of the lowest end of the outdoor unit 2. The
electromagnetic induction heating unit 6 is disposed in the machine
chamber, in an upper position in proximity to the right side panel
2f and the ceiling plate 2a. The heat exchange fins 23z of the
outdoor heat exchanger 23 described above are arranged so as to be
aligned in the plate-thickness direction while the plate-thickness
direction runs generally horizontally. The converging tube J is
placed in the lowest parts of the heat exchange fins 23z of the
outdoor heat exchanger 23, by passing through the heat exchange
fins 23z in the thickness direction. The hot gas bypass circuit H
is disposed so as to extend below the outdoor fans 26 and the
outdoor heat exchanger 23.
[0097] <1-3> Internal Configuration of Outdoor Unit 2
[0098] FIG. 5 shows an overall front perspective view showing the
internal structure of the machine chamber of the outdoor unit 2.
FIG. 6 shows a perspective view showing the internal structure of
the machine chamber of the outdoor unit 2. FIG. 7 shows a
perspective view depicting the arrangement relationship between the
outdoor heat exchanger 23 and the bottom plate 2b.
[0099] The partitioning plate 2H partitions the outdoor unit 2
frontward to rearward from the top end to the bottom end, so as to
section the outdoor unit 2 into an air-blower chamber in which the
outdoor heat exchanger 23, the outdoor fans 26, and other
components are placed, and a machine chamber in which the
electromagnetic induction heating unit 6, the compressor 21, the
accumulator 25, and other components are placed. The compressor 21
and the accumulator 25 are placed in a space below the machine
chamber of the outdoor unit 2. The electromagnetic induction
heating unit 6, the four-way switching valve 22, and the outdoor
control part 12 are placed in an upper space of the machine chamber
of the outdoor unit 2, which is also a space at the top of the
compressor 21, the accumulator 25, and other components. The
functional elements constituting the outdoor unit 2 and placed in
the machine chamber, which are the compressor 21, the four-way
switching valve 22, the outdoor heat exchanger 23, the outdoor
electric expansion valve 24, the accumulator 25, the hot gas bypass
valve 27, the capillary tube 28, and the electromagnetic induction
heating unit 6, are connected via the discharge tube A, the
indoor-side gas tube B, the outdoor-side liquid tube D, the
outdoor-side gas tube E, the accumulation tube F, the hot gas
bypass circuit H, and other components so that the refrigeration
cycle is performed by the refrigerant circuit 10 shown in FIG. 1.
The hot gas bypass circuit H is configured from nine portions
linked, which are a first bypass portion H1 through to a ninth
bypass portion H9 as described hereinafter, and when refrigerant
flows through the hot gas bypass circuit H, the refrigerant flows
sequentially from the first bypass portion H1 to the ninth bypass
portion H9.
[0100] <1-4> Converging Tube J and Branched Tube K
[0101] The converging tube J shown in FIG. 7 has a cross-sectional
area equivalent to the cross-sectional areas of the first branched
tube K1, the second branched tube K2, and the third branched tube
K3 as described above, and within the outdoor heat exchanger 23,
the portion containing the first branched tube K1, the second
branched tube K2, and the third branched tube K3 can be increased
in terms of its heat exchange effective surface area relative to
that of the converging tube J. In the portion of the converging
tube J, a large amount of refrigerant collects and flows more
intensively than in the portion of the first branched tube K1, the
second branched tube K2, and the third branched tube K3; and the
growth of ice below the outdoor heat exchanger 23 can therefore be
suppressed more effectively. The converging tube J herein is
composed of a first converging tube portion J1, a second converging
tube portion J2, a third converging tube portion J3, and a fourth
converging tube portion J4 connected to each other, as shown in
FIG. 7. Refrigerant that has flowed into the outdoor heat exchanger
23 through the branched tube K converges at the
converging/branching point 23j, in which state the refrigerant in
the refrigerant circuit 10 can make a pass through the lowest end
portion of the outdoor heat exchanger 23 after having collected
into one flow. The first converging tube portion J1 extends from
the converging/branching point 23j to the heat exchange fins 23z
disposed in the outermost edge of the outdoor heat exchanger 23.
The second converging tube portion J2 extends from the end of the
first converging tube portion J1 so as to pass through the
plurality of heat exchange fins 23z. As with the second converging
tube portion J2, the fourth converging tube portion J4 also extends
so as to pass through the plurality of heat exchange fins 23z. The
third converging tube portion J3 is a U-shaped tube which connects
the second converging tube portion J2 and the fourth converging
tube portion J4 in the end of the outdoor heat exchanger 23. During
the air-cooling operation, since the flow of refrigerant in the
refrigerant circuit 10 collects from a multiple-split flow in the
branched tube K into a single flow in the converging tube J, the
refrigerant can collect into a single flow in the converging tube J
even if the degree of subcooling of the refrigerant flowing through
the branched tube K in the portion immediately before the
converging/branching point 23j differs with each set of refrigerant
flowing through the individual tubes constituting the branched tube
K, and the degree of subcooling of the outlet of the outdoor heat
exchanger 23 can therefore be adjusted. When the defrosting
operation is performed during the air-warming operation, the hot
gas bypass valve 27 is opened and high-temperature refrigerant
discharged from the compressor 21 can be supplied to the converging
tube J provided at the bottom end of the outdoor heat exchanger 23
before being supplied to the other portions of the outdoor heat
exchanger 23. Therefore, ice deposited in the lower vicinity of the
outdoor heat exchanger 23 can be effectively thawed.
[0102] <1-5> Hot Gas Bypass Circuit H
[0103] FIG. 8 shows a plan view in which the air-blowing mechanism
of the outdoor unit 2 has been removed. FIG. 9 shows a plan view of
the placement relationship between the bottom plate of the outdoor
unit 2 and the hot gas bypass circuit H.
[0104] The hot gas bypass circuit H has a first bypass portion H1
through to an eighth bypass portion H8 as shown in FIGS. 8 and 9,
and also a ninth bypass portion H9 which is not shown. In the hot
gas bypass circuit H, the portion that branches at the branching
point A1 from the discharge tube A, extends to the hot gas bypass
valve 27, and further extends from this hot gas bypass valve 27 is
the first bypass portion H1. The second bypass portion H2 extends
from the end of the first bypass portion H1 toward the air-blower
chamber near the rear side. The third bypass portion H3 extends
toward the front side from the end of the second bypass portion H2.
The fourth bypass portion H4 extends in the opposite direction of
the machine chamber, toward the left, from the end of the third
bypass portion H3. The fifth bypass portion H5 extends toward the
rear side from the end of the fourth bypass portion H4, up to a
portion where a gap can be ensured from the rear side panel 2e of
the outdoor unit casing. The sixth bypass portion H6 extends from
the end of the fifth bypass portion H5 toward the machine chamber
at the right and toward the rear side. The seventh bypass portion
H7 extends from the end of the sixth bypass portion H6 toward the
machine chamber at the right and through the inside of the
air-blower chamber. The eighth bypass portion H8 extends through
the inside of the machine chamber from the end of the seventh
bypass portion H7. The ninth bypass portion H9 extends from the end
of the eighth bypass portion H8 until it reaches the capillary tube
28. When the hot gas bypass valve 27 has been opened, refrigerant
flows through the hot gas bypass circuit H in sequence from the
first bypass portion H1 to the ninth bypass portion H9 as described
above. Therefore, the refrigerant that braches at the branching
point A1 of the discharge tube A extending from the compressor 21
flows to the first bypass portion H1 before the refrigerant flowing
through the ninth bypass portion H9. Therefore, viewing the
refrigerant flowing through the hot gas bypass circuit H as a
whole, the refrigerant that has flowed through the fourth bypass
portion H4 then continues to flow to the fifth through eighth
bypass portions H8, the temperature of the refrigerant flowing
through the fourth bypass portion H4 readily becomes higher than
the temperature of the refrigerant flowing through the fifth
through eighth bypass portions H8.
[0105] Thus, the hot gas bypass circuit H is placed in the bottom
plate 2b of the outdoor unit casing so as to pass near the portion
below the outdoor fans 26 and below the outdoor heat exchanger 23.
Therefore, the vicinity of the portion where the hot gas bypass
circuit H passes can be warmed by the high-temperature refrigerant
branched and supplied from the discharge tube A of the compressor
21 without the use of a heater or another separate heat source.
Consequently, even if the top side of the bottom plate 2b is wetted
by rainwater or by drain water produced in the outdoor heat
exchanger 23, the formation of ice can be suppressed in the bottom
plate 2b below the outdoor fans 26 and below the outdoor heat
exchanger 23. It is thereby possible to avoid situations in which
the driving of the outdoor fans 26 is hindered by ice and
situations in which the surface of the outdoor heat exchanger 23 is
covered by ice, reducing heat exchange efficiency. The hot gas
bypass circuit H is arranged so as to pass below the outdoor fans
26 after branching at the branching point A1 of the discharge tube
A and before passing below the outdoor heat exchanger 23.
Therefore, the formation of ice below the outdoor fans 26 can be
prevented with greater priority.
[0106] <1-6> Electromagnetic Induction Heating Unit 6
[0107] FIG. 10 shows a schematic perspective view of the
electromagnetic induction heating unit 6 attached to the
accumulation tube F. FIG. 11 shows an external perspective view in
which a shielding cover 75 has been removed from the
electromagnetic induction heating unit 6. FIG. 12 shows a
cross-sectional view of the electromagnetic induction heating unit
6 attached to the accumulation tube F.
[0108] The electromagnetic induction heating unit 6 is placed so as
to cover the magnetic tube F2 from the radially outer side, the
magnetic tube F2 being the heat-generating portion of the
accumulation tube F, and the magnetic tube F2 is made to generate
heat by electromagnetic induction heating. This heat-generating
portion of the accumulation tube F has a double-layered tube
structure having the copper tube F1 on the inner side and the
magnetic tube F2 on the outer side.
[0109] The electromagnetic induction heating unit 6 comprises a
first hexagonal nut 61, a second hexagonal nut 66, a first bobbin
cover 63, a second bobbin cover 64, a bobbin main body 65, a first
ferrite case 71, a second ferrite case 72, a third ferrite case 73,
a fourth ferrite case 74, a first ferrite 98, a second ferrite 99,
a coil 68, the shielding cover 75, an electromagnetic induction
thermistor 14, a fuse 15, and other components.
[0110] The first hexagonal nut 61 and the second hexagonal nut 66
are made of a resin, and are used to stabilize the fixed state
between the electromagnetic induction heating unit 6 and the
accumulation tube F with the aid of a C ring (not shown). The first
bobbin cover 63 and the second bobbin cover 64 are made of a resin
and are used to cover the accumulation tube F from the radially
outer side in the top end position and bottom end position,
respectively. The first bobbin cover 63 and the second bobbin cover
64 have four screw holes for screws 69, whereby the first through
fourth first ferrite cases 71 to 74 described hereinafter are
screwed in via the screws 69. Furthermore, the second bobbin cover
64 has an electromagnetic induction thermistor insertion opening
64f for inserting the electromagnetic induction thermistor 14 shown
in FIG. 12 and attaching it to the outer surface of the magnetic
tube F2. The second bobbin cover 64 has a fuse insertion opening
64e (see FIG. 14) for inserting the fuse 15 shown in FIG. 13 and
attaching it to the outer surface of the magnetic tube F2. The
electromagnetic induction thermistor 14 has an electromagnetic
induction thermistor detector 14a, an outer projection 14b, a side
projection 14c, and electromagnetic induction thermistor wires 14d
for converting the detection result of the electromagnetic
induction thermistor detector 14a to a signal and sending it to the
control part 11, as shown in FIG. 12. The electromagnetic induction
thermistor detector 14a has a shape that conforms to the curved
shape of the outer surface of the accumulation tube F, and has a
substantial contact surface area. The fuse 15 has a fuse detector
15a, an asymmetrical shape 15b, and fuse wires 15d for converting
the detection result of the fuse detector 15a to a signal and
sending it to the control part 11, as shown in FIG. 13. Having
received from the fuse 15 a notification that a temperature
exceeding a predetermined limit temperature has been detected, the
control part 11 performs a control for stopping the supply of
electricity to the coil 68, avoiding heat damage to the equipment.
The bobbin main body 65 is made of a resin and the coil 68 is wound
over the bobbin main body 65. The coil 68 is wound in a helical
shape over the outer side of the bobbin main body 65, the axial
direction being the direction in which the accumulation tube F
extends. The coil 68 is connected to a control print board (not
shown), and the coil receives a supply of high-frequency electric
current. The output of the control print board is controlled by the
control part 11. The electromagnetic induction thermistor 14 and
the fuse 15 are attached in a state in which the bobbin main body
65 and the second bobbin cover 64 have been joined together, as
shown in FIG. 14. When the electromagnetic induction thermistor 14
has been attached, a satisfactory state of pressurized contact with
the outer surface of the magnetic tube F2 is maintained by a plate
spring 16 pushing radially inward on the magnetic tube F2.
Similarly, in the attachment of the fuse 15, a satisfactory state
of pressurized contact with the outer surface of the magnetic tube
F2 is maintained by a plate spring 17 pushing radially inward on
the magnetic tube F2. Thus, since the electromagnetic induction
thermistor 14 and the fuse 15 stay satisfactorily in firm contact
with the outer surface of the accumulation tube F, responsiveness
is improved and sudden temperature changes caused by
electromagnetic induction heating can be quickly detected. The
first bobbin cover 63 and the second bobbin cover 64 are held in by
the first ferrite case 71 from the direction in which the
accumulation tube F extends and are screwed in place by the screws
69. The first ferrite case 71 through the fourth ferrite case 74
house the first ferrite 98 and the second ferrite 99, which are
configured from the highly magnetically permeable material ferrite.
The first ferrite 98 and the second ferrite 99 absorb the magnetic
field created by the coil 68 and form a magnetic flux pathway,
thereby impeding the magnetic field from leaking out to the
exterior, as shown in the cross-sectional view of the accumulation
tube F and electromagnetic induction heating unit 6 of FIG. 15. The
shielding cover 75 is placed around the outermost periphery of the
electromagnetic induction heating unit 6, and collects a magnetic
flux that cannot be contained with the first ferrite 98 and the
second ferrite 99 alone. The magnetic flux mostly does not leak out
past the shielding cover 75, and the location where the magnetic
flux is created can be determined arbitrarily.
[0111] <1-7> Electromagnetic Induction Heating Control
[0112] The electromagnetic induction heating unit 6 described above
performs a control for causing the magnetic tube F2 of the
accumulation tube F to generate heat, during startup in which the
air-warming operation is initiated when the refrigeration cycle is
caused to perform the air-warming operation, during air-warming
capability assistance, and during performing of the defrosting
operation.
[0113] The description hereinbelow pertains to the time of
startup.
[0114] When an air-warming operation command is inputted to the
controller 90 from the user, the control part 11 initiates the
air-warming operation. When the air-warming operation is initiated,
the control part 11 waits until the compressor 21 has started up
and the pressure detected by the pressure sensor 29a has risen to
39 kg/cm.sup.2, and then causes the indoor fan 42 to be driven.
This prevents discomfort for the user due to unwarmed air flowing
into the room in the stage at which the refrigerant passing through
the indoor heat exchanger 41 has not yet been warmed.
Electromagnetic induction heating using the electromagnetic
induction heating unit 6 is performed here in order to shorten the
time for the compressor 21 to start up and the pressure detected by
the pressure sensor 29a to reach 39 kg/cm.sup.2. During this
electromagnetic induction heating, since the temperature of the
accumulation tube F rises rapidly, prior to initiating
electromagnetic induction heating, the control part 11 performs a
control for determining whether or not conditions are suitable for
initiating electromagnetic induction heating. Examples of such a
determination include a flow condition judgment process, a
sensor-separation detection process, a rapid pressure-increasing
process, and the like, as shown in the time chart of FIG. 16.
[0115] <1-8> Flow Condition Judgment Process
[0116] When electromagnetic induction heating is performed, the
heating load is only the refrigerant accumulated in the portion of
the accumulation tube F where the electromagnetic induction heating
unit 6 is attached while refrigerant is not flowing to the
accumulation tube F. Thus, when electromagnetic induction heating
by the electromagnetic induction heating unit 6 is performed while
refrigerant is not flowing to the accumulation tube F, the
temperature of the accumulation tube F rises abnormally to an
extent such that the refrigerator oil deteriorates. The temperature
of the electromagnetic induction heating unit 6 itself also rises,
and the reliability of the equipment is reduced. Therefore, a flow
condition judgment process is performed herein which ensures that
refrigerant flows to the accumulation tube F during a stage prior
to initiating electromagnetic induction heating, so that
electromagnetic induction heating by the electromagnetic induction
heating unit 6 is not performed while refrigerant is not flowing to
the accumulation tube F.
[0117] In the flow condition judgment process, the following
processes are performed as shown in the flowchart of FIG. 17.
[0118] In step S11, the control part 11 determines whether or not
the controller 90 has received a command from the user for the
air-warming operation and not for the air-cooling operation. Such a
determination is made because the refrigerant must be heated by the
electromagnetic induction heating unit 6 under the conditions in
which the air-warming operation is performed.
[0119] In step S12, the control part 11 initiates startup of the
compressor 21, and the frequency of the compressor 21 gradually
increases.
[0120] In step S13, the control part 11 determines whether or not
the frequency of the compressor 21 has reached a predetermined
minimum frequency Qmin, and proceeds to step S14 when it has
determined that the minimum frequency has been reached.
[0121] In step S14, the control part 11 initiates the flow
condition judgment process, stores detected temperature data of the
electromagnetic induction thermistor 14 and detected temperature
data of the outdoor heat exchange temperature sensor 29c at the
time the frequency of the compressor 21 reached the predetermined
minimum frequency Qmin (see point a in FIG. 16), and initiates a
count of the flow detection time by the timer 95. If the frequency
of the compressor 21 has not yet reached the predetermined minimum
frequency Qmin, the refrigerant flowing through the accumulation
tube F and the outdoor heat exchanger 23 is in a gas-liquid double
phase and maintains a constant temperature at the saturation
temperature, and the temperatures detected by the electromagnetic
induction thermistor 14 and the outdoor heat exchange temperature
sensor 29c are therefore constant and unchanging at the saturation
temperature. However, the frequency of the compressor 21 continues
to increase after some time, the refrigerant pressures in the
outdoor heat exchanger 23 and in the accumulation tube F continue
to decrease further, and the saturation temperature begins to
decrease, whereby the temperatures detected by the electromagnetic
induction thermistor 14 and the outdoor heat exchange temperature
sensor 29c begin to decrease. Since the outdoor heat exchanger 23
herein is positioned farther downstream than the accumulation tube
F in relation to the intake side of the compressor 21, the timing
at which the temperature of refrigerant passing through the outdoor
heat exchanger 23 begins to decrease is earlier than the timing at
which the temperature of refrigerant passing through the
accumulation tube F begins to decrease (see points b and c in FIG.
16).
[0122] In step S15, the control part 11 determines whether or not
the flow detection time of 10 seconds has elapsed since the timer
95 began counting, and the process transitions to step S16 when the
flow detection time has elapsed. When the flow detection time has
not yet elapsed, step S15 is repeated.
[0123] In step S16, the control part 11 acquires detected
temperature data of the electromagnetic induction thermistor 14 and
detected temperature data of the outdoor heat exchange temperature
sensor 29c at the time that the flow detection time has elapsed and
the refrigerant temperatures in the outdoor heat exchanger 23 and
in the accumulation tube F have decreased, and the process then
transitions to step S17.
[0124] In step S17, the control part 11 determines whether or not
the detected temperature of the electromagnetic induction
thermistor 14 acquired in step S16 has fallen 3.degree. C. or more
below the detected temperature data of the electromagnetic
induction thermistor 14 stored in step S14, and also determines
whether or not the detected temperature of the outdoor heat
exchange temperature sensor 29c acquired in step S16 has fallen
3.degree. C. or more below the detected temperature data of the
outdoor heat exchange temperature sensor 29c stored in step S14.
Specifically, it is determined whether or not a decrease in the
refrigerant temperature was successfully detected during the flow
detection time. When either the detected temperature of the
electromagnetic induction thermistor 14 or the detected temperature
of the outdoor heat exchange temperature sensor 29c has fallen by
3.degree. C. or more, it is determined that refrigerant is flowing
through the accumulation tube F and a refrigerant flow has been
ensured, the flow condition judgment process is ended, and a
transition is made either to the rapid pressure-increasing process
during startup in which the output of the electromagnetic induction
heating unit 6 is used at its maximum limit, to the
sensor-separation detection process, or to another process.
[0125] On the other hand, when neither the detected temperature of
the electromagnetic induction thermistor 14 nor the detected
temperature of the outdoor heat exchange temperature sensor 29c has
fallen by 3.degree. C. or more, the process transitions to step
S18.
[0126] In step S18, the control part 11 assumes that the quantity
of refrigerant flowing through the accumulation tube F is
insufficient for induction heating by the electromagnetic induction
heating unit 6, and the control part 11 outputs a flow abnormality
display on the display screen of the controller 90.
[0127] <1-9> Sensor-Separation Detection Process
[0128] The sensor-separation detection process is a process for
confirming the state of attachment of the electromagnetic induction
thermistor 14, and is performed after the electromagnetic induction
thermistor 14 is attached to the accumulation tube F and the air
conditioning apparatus 1 is finished being installed (after
installation is finished, including after the breaker supplying
electricity to the electromagnetic induction heating unit 6 has
tripped), when the air-warming operation is first initiated.
Specifically, the control part 11 performs the sensor-separation
detection process after it has been determined in the
above-described flow condition judgment process that the flow
quantity of refrigerant in the accumulation tube F has been
ensured, and prior to the performing of the rapid
pressure-increasing process during startup in which the output of
the electromagnetic induction heating unit 6 is used at its maximum
limit.
[0129] When the air conditioning apparatus 1 is being transported,
unanticipated vibrations or other factors can cause the
electromagnetic induction thermistor 14 to be in an unstably
attached state or a detached state, and when a newly transported
electromagnetic induction heating unit 6 is operated for the first
time, its reliability in particular is required, and when a newly
transported electromagnetic induction heating unit 6 operates for
the first time in the proper manner, it can be forecast, to a
certain extent, that subsequent operations will be stable.
Therefore, the sensor-separation detection process is performed
with the timing described above.
[0130] In the sensor-separation detection process, the following
processes are performed as shown in the flowchart of FIG. 18.
[0131] In step S21, the control part 11 initiates the supply of
electricity to the coil 68 of the electromagnetic induction heating
unit 6, while ensuring the refrigerant flow quantity in the
accumulation tube F that was confirmed by the flow condition
judgment process, or a greater refrigerant flow quantity, and while
storing detected temperature data of the electromagnetic induction
thermistor 14 (see point d in FIG. 16) at the time the flow
detection time has ended (i.e., the starting time point of the
sensor-separation detection time). Electricity is supplied to the
coil 68 of the electromagnetic induction heating unit 6 here for
the sensor-separation detection time of 20 seconds, at a separation
detection supply of electricity M1 (1 kW) of an output 50% less
than a predetermined maximum supplied electricity Mmax (2 kW). In
this stage, since the state of attachment of the electromagnetic
induction thermistor 14 is not yet confirmed to be satisfactory,
the output is reduced to 50%, so that the fuse 15 will not be
damaged and the resin members of the electromagnetic induction
heating unit 6 will not melt due to the electromagnetic induction
thermistor 14 being unable to detect this abnormal rise in
temperature regardless of any abnormal rise in temperature in the
accumulation tube F. At the same time, the continuous heating time
duration of the electromagnetic induction heating unit 6 is set in
advance so as not to exceed the maximum continuous output time of
10 minutes, and the control part 11 therefore causes the timer 95
to begin counting the elapsed time in which the electromagnetic
induction heating unit 6 continues to output. The supply of
electricity to the coil 68 of the electromagnetic induction heating
unit 6 and the size of the magnetic field generated by the coil 68
around itself are correlated values.
[0132] In step S22, the control part 11 determines whether or not
the sensor-separation detection time has ended. If the
sensor-separation detection time has ended, the process transitions
to step S23. If the sensor-separation detection time has not yet
ended, step S22 is repeated.
[0133] In step S23, the control part 11 acquires the detected
temperature of the electromagnetic induction thermistor 14 at the
point in time when the sensor-separation detection time ended
(point e of FIG. 16), and the process transitions to step S24.
[0134] In step S24, the control part 11 determines whether or not
the detected temperature of the electromagnetic induction
thermistor 14 at the end of the sensor-separation detection time
acquired in step S23 has risen 10.degree. C. or more above the
detected temperature data of the electromagnetic induction
thermistor 14 at the start of the sensor-separation detection time
stored in step S21. Specifically, a determination is made as to
whether or not the refrigerant temperature has risen by 10.degree.
C. or more due to the induction heating by the electromagnetic
induction heating unit 6 during the sensor-separation detection
time. When the detected temperature of the electromagnetic
induction thermistor 14 has risen by 10.degree. C. or more, it is
determined that confirmation could be made that the state of
attachment of the electromagnetic induction thermistor 14 to the
accumulation tube F is satisfactory and that the accumulation tube
F has been appropriately warmed by the induction heating of the
electromagnetic induction heating unit 6, the sensor-separation
detection process is ended, and the process transitions to the
rapid pressure-increasing process at startup in which the output of
the electromagnetic induction heating unit 6 is used to its maximum
limit. On the other hand, if the detected temperature of the
electromagnetic induction thermistor 14 has not risen by 10.degree.
C. or more, the process transitions to step S25.
[0135] In step S25, the control part 11 counts the number of times
a sensor-separation retry process was performed. When the number of
retries is less than ten, the process transitions to step S26, and
when the number of retries exceeds ten, the process transitions to
step S27 without transitioning to step S26.
[0136] In step S26, the control part 11 executes the
sensor-separation retry process. Herein the detected temperature
data of the electromagnetic induction thermistor 14 at the elapse
of 30 more seconds (not shown in FIG. 16) is stored, electricity is
supplied at a separation detection supply of electricity M1 to the
coil 68 of the electromagnetic induction heating unit 6 for 20
seconds, the same processes of steps S22 and S23 are performed, the
sensor-separation detection process is ended when the detected
temperature of the electromagnetic induction thermistor 14 has
risen by 10.degree. C. or more, and the process transitions to the
rapid pressure-increasing process at startup in which the output of
the electromagnetic induction heating unit 6 is used to its maximum
limit. On the other hand, if the detected temperature of the
electromagnetic induction thermistor 14 has not risen by 10.degree.
C. or more, the process returns to step S25.
[0137] In step S27, the control part 11 determines that the state
of attachment of the electromagnetic induction thermistor 14 to the
accumulation tube F is unstable or unsatisfactory, and outputs a
sensor-separated abnormality display on the display screen of the
controller 90.
[0138] <1-10> Rapid Pressure-Increasing Process
[0139] The control part 11 initiates the rapid pressure-increasing
process in a state in which the flow condition judgment process and
the sensor-separation detection process have ended, confirmation
has been made that sufficient refrigerant flow in the accumulation
tube F has been ensured, the state of attachment of the
electromagnetic induction thermistor 14 to the accumulation tube F
is satisfactory, and the accumulation tube F has been appropriately
warmed by induction heating by the electromagnetic induction
heating unit 6.
[0140] Even if induction heating by the electromagnetic induction
heating unit 6 is performed here at high output, the reliability of
the air conditioning apparatus 1 is successfully improved because
it is confirmed that there is no abnormal rise in temperature in
the accumulation tube F.
[0141] In the rapid pressure-increasing process, the following
processes are performed as shown in the flowchart of FIG. 19.
[0142] In step S31, the control part 11 sets the supply of
electricity to the coil 68 of the electromagnetic induction heating
unit 6 not to the separation detection supply of electricity M1
limited to 50% output as it was during the sensor-separation
detection process described above, but rather to the predetermined
maximum supplied electricity Mmax (2 kW). This output by the
electromagnetic induction heating unit 6 is continued until the
pressure sensor 29a reaches a predetermined target high pressure
Ph.
[0143] To prevent abnormal high-pressure increases in the
refrigeration cycle of the air conditioning apparatus 1, the
control part 11 forces the compressor 21 to stop when the pressure
sensor 29a detects an abnormally high pressure Pr. The target high
pressure Ph during this rapid pressure-increasing process is
provided as a separate threshold that is a pressure value smaller
than the abnormally high pressure Pr.
[0144] In step S32, the control part 11 determines whether or not
the maximum continuous output time of 10 minutes of the
electromagnetic induction heating unit 6 has elapsed since the
start of the count in step S21 of the sensor-separation detection
process. If the maximum continuous output time has not elapsed, the
process advances to step S33. If the maximum continuous output time
has elapsed, the process advances to step S34.
[0145] In step S33, the control part 11 determines whether or not
the detected pressure of the pressure sensor 29a has reached the
target high pressure Ph. If the target high pressure Ph has been
reached, the process transitions to step S34. If the target high
pressure Ph has not been reached, step S32 is repeated.
[0146] In step S34, the control part 11 initiates driving of the
indoor fan 42, ends the rapid pressure-increasing process, and
transitions to a steady output process.
[0147] When the process advances herein from step S33 to step S34,
the indoor fan 42 begins to operate under conditions in which
sufficiently warm conditioned air is successfully being provided to
the user. When the process advances from step S32 to step S34, a
state of successfully providing the user with sufficiently warm
conditioned air has not been reached, but conditioned air that is
somewhat warm can be supplied and the supply of warm air can be
initiated in a range wherein the elapsed time since the start of
the air-warming operation is not too long.
[0148] <1-11> Steady Output Process
[0149] In the steady output process, a steadily supplied
electricity M2 (1.4 kW), which is equal to or greater than the
separated-detection supply of electricity M1 (1 kW) and equal to or
less than the maximum supplied electricity Mmax (2 kW), is
designated as a fixed output value, and the frequency at which
electricity is supplied to the electromagnetic induction heating
unit 6 is PI controlled so that the detected temperature of the
electromagnetic induction thermistor 14 is maintained at the
startup target accumulation tube temperature of 80.degree. C.
[0150] In the steady output process, the following processes are
performed as shown in the flowchart of FIG. 20.
[0151] In step S41, the control part 11 stores the detected
temperature of the electromagnetic induction thermistor 14 and the
process transitions to step S42.
[0152] In step S42, the control part 11 compares the detected
temperature of the electromagnetic induction thermistor 14 stored
in step S41 with the startup target accumulation tube temperature
of 80.degree. C., and determines whether or not the detected
temperature of the electromagnetic induction thermistor 14 is equal
to or less than a predetermined maintained temperature that is
lower than the startup target accumulation tube temperature of
80.degree. C. by a predetermined temperature. If the detected
temperature is equal to or less than the predetermined maintained
temperature, the process transitions to step S43. If the detected
temperature is not equal to or less than the predetermined
maintained temperature, the process stands by until the detected
temperature is equal to or less than the predetermined maintained
temperature.
[0153] In step S43, the control part 11 perceives the time elapsed
since the end of the most recent supply of electricity to the
electromagnetic induction heating unit 6.
[0154] In step S44, the control part 11 designates, as one set, the
continuous supply of electricity to the electromagnetic induction
heating unit 6 fixed at the steadily supplied electricity M2 (1.4
kW) for 30 seconds, and performs PI control in which the frequency
of this set is increased in response to a longer elapsed time
ascertained in step S43.
[0155] <1-12> Defrosting Process
[0156] When the steady output process described above is continued
and the detected temperature of the outdoor heat exchange
temperature sensor 29c of the outdoor heat exchanger 23 is a
predetermined value or lower, the defrosting process, which is an
operation for melting frost adhering to the outdoor heat exchanger
23, is performed. Specifically, similar to setting the connection
state of the four-way switching valve 22 to the air-cooling
operation (the connection state shown by the dashed lines of FIG.
1), high-pressure, high-temperature gas refrigerant discharged from
the compressor 21 is supplied to the outdoor heat exchanger 23
before passing through the indoor heat exchanger 41, and the heat
of condensation of the refrigerant is used to melt the frost
adhering to the outdoor heat exchanger 23.
[0157] In the defrosting process, the following processes are
performed as shown in the flowchart of FIG. 21.
[0158] In step S51, the control part 11 confirms that the frequency
of the compressor 21 is equal to or greater than the predetermined
minimum frequency Qmin, which ensures a predetermined refrigerant
circulating quantity; that a refrigerant flow quantity is ensured
by the flow condition judgment process to an extent such that
electromagnetic induction heating can be performed; and that the
state of attachment of the electromagnetic induction thermistor 14
is proper according to the sensor-separation detection process; and
transitions to step S52.
[0159] In step S52, the control part 11 determines whether or not
the detected temperature of the outdoor heat exchange temperature
sensor 29c is less than 10.degree. C. If it is less than 10.degree.
C., the process transitions to step S53. If it is not less than
10.degree. C., step S52 is repeated.
[0160] In step S53, the control part 11 brings induction heating by
the electromagnetic induction heating unit 6 to a halt and
transmits a defrost signal.
[0161] In step S54, after transmitting a defrost signal, the
control part 11 sets the connection state of the four-way switching
valve 22 to the connection state of the air-cooling operation, and
also performs a count, using the timer 95, of the time elapsed
after defrosting is initiated, once the connection state of the
four-way switching valve 22 has become the connection state of the
air-cooling operation.
[0162] In step S55, the control part 11 determines whether or not
30 seconds has elapsed since defrosting was initiated. If 30
seconds has elapsed, the process transitions to step S56. If 30
seconds has not elapsed, step S55 is repeated.
[0163] In step S56, the control part 11 brings the electricity
supplied to the coil 68 of the electromagnetic induction heating
unit 6 to a predetermined maximum supplied electricity Mmax (2 kW),
and PI controls the frequency of induction heating by the
electromagnetic induction heating unit 6 so that the detected
temperature of the electromagnetic induction thermistor 14 reaches
the target defrosting temperature, which is 40.degree. C.
(different from the startup target accumulation tube temperature
during the steady output process). When the detected temperature of
the outdoor heat exchange temperature sensor 29c falls below
0.degree. C., the hot gas bypass valve 27 of the hot gas bypass
circuit H then opens, high-temperature, high-pressure gas
refrigerant is supplied to the area below the outdoor fans 26 and
below the outdoor heat exchanger 23 on the top surface of the
bottom plate 2b of the outdoor unit 2, and the ice formed on the
top surface of the bottom plate 2b is removed. Since the connection
state of the four-way switching valve 22 is switched to the state
of the air-cooling operation, the high-temperature, high-pressure
gas refrigerant discharged from the compressor 21 flows from the
branching/converging point 23k to the converging/branching point
23j of the outdoor heat exchanger 23 and converges into a single
flow in the converging/branching point 23j, whereby refrigerant
three times greater in quantity than that of the branched tube K
flows collectively through the converging tube J. Since the
converging tube J is positioned in the vicinity of the bottom end
of the outdoor heat exchanger 23, much heat of condensation can be
collectively supplied to the bottom end vicinity of the outdoor
heat exchanger 23. Defrosting can thereby be further quickened.
[0164] In step S57, the control part 11 determines whether or not
the defrost initiation elapsed time has exceeded 10 minutes. If it
has not exceeded 10 minutes, the process transitions to step S58.
If it has exceeded 10 minutes, the process transitions to step S59.
The connection state of the four-way switching valve 22 can thereby
be prevented from remaining for 10 minutes or more in the
air-cooling state, making it unlikely that the user will experience
discomfort from a decrease in the indoor temperature.
[0165] In step S58, the control part 11 determines whether or not
the detected temperature of the outdoor heat exchange temperature
sensor 29c exceeds 10.degree. C. If it exceeds 10.degree. C., the
process transitions to step S59. If it does not exceed 10.degree.
C., the process returns to and repeats step S56.
[0166] In step S59, the control part 11 stops the compressor 21 to
equalize the high and low pressures in the refrigeration cycle, and
ends induction heating by the electromagnetic induction heating
unit 6.
[0167] In step S60, the control part 11 switches the connection
state of the four-way switching valve 22 to the connection state of
the air-warming operation.
[0168] The control part 11 then transmits a signal which ends
defrosting. Furthermore, the control part 11 progressively raises
the frequency of the compressor 21 to the predetermined minimum
frequency Qmin or greater, and performs the steady output process
until a condition is reached in which the defrosting process will
be performed again. The hot gas bypass valve 27 of the hot gas
bypass circuit H closes after 5 seconds following the transmission
of the signal that ends defrosting.
Characteristics of Air Conditioning Apparatus 1 of Present
Embodiment
[0169] In the air conditioning apparatus 1, performing the rapid
pressure-increasing process causes a process to be performed in
which the output of the electromagnetic induction heating unit 6 is
brought to the maximum supplied electricity Mmax (2 kW), and the
refrigerant flowing toward the indoor heat exchanger 41 is quickly
brought to a high temperature and high pressure. It is thereby
possible to shorten the time needed for warm air to be supplied to
the user after startup of the air-warming operation is initiated.
Furthermore, by performing the steady output process in a state in
which the room interior has been warmed to some extent, the
steadily supplied electricity M2 (1.4 kW), which is the output of
the electromagnetic induction heating unit 6 limited below the
maximum supplied electricity Mmax (2 kW), is brought to a fixed
output value. It is thereby possible to minimize control
overshooting caused by excessively raising the output of the
electromagnetic induction heating unit 6.
[0170] When electromagnetic induction heating is performed, sudden
temperature increases typically occur more readily than temperature
increases caused by changes in the refrigerant circulation
conditions in the refrigeration cycle. As a countermeasure to this,
in the electromagnetic induction heating unit 6 of the air
conditioning apparatus 1, the electromagnetic induction thermistor
14, which is pressed against the magnetic tube F2 by the elastic
force of the plate spring 16, maintains satisfactory responsiveness
to rapid temperature changes caused by electromagnetic induction
heating during the above-described steady output process achieved
by electromagnetic induction heating. Therefore, the responsiveness
of the steady output process is satisfactory, and control
overshooting can be further minimized.
[0171] In the defrosting process, since induction heating by the
electromagnetic induction heating unit 6 is performed at the
maximum supplied electricity Mmax (2 kW), the defrosting process
can be quickened. Since the detected temperature of the
electromagnetic induction thermistor 14 is brought to the target
defrosting temperature of 40.degree. C. and suppressed lower than
the startup target accumulation tube temperature during the steady
output process, overshooting caused by control is kept to a
minimum.
Other Embodiments
[0172] Embodiments of the present invention were described above
based on the drawings, but the specific configuration is not
limited to these embodiments, and modifications can be made within
a range that does not deviate from the scope of the invention.
[0173] (A)
[0174] In the embodiment described above, an example was described
of a case in which the rapid pressure-increasing process of causing
the electromagnetic induction heating unit 6 to output at the
maximum supplied electricity Mmax (2 kW) is ended at the point in
time when the detected pressure of the pressure sensor 29a reaches
the target high pressure Ph.
[0175] However, the present invention is not limited to this
example.
[0176] The rapid pressure-increasing process of causing the
electromagnetic induction heating unit 6 to output at the maximum
supplied electricity Mmax (2 kW) may, for example, be ended at the
point in time when the electromagnetic induction thermistor 14
detects a temperature established based on the temperature
corresponding to the refrigerant of the target high pressure Ph
passing through the attached portion of the pressure sensor
29a.
[0177] In this case as well, since it is possible to confirm that
the refrigerant supplied to the indoor heat exchanger 41 is
sufficiently high in temperature, this confirmation can be used as
a determination indicator for initiating the supply of warm
conditioned air to the user at the start of the air-warming
operation.
[0178] With this type of electromagnetic induction thermistor 14,
detecting temperature changes when determining the time of ending
the rapid pressure-increasing process may be done by detecting the
temperature of an electromagnetic induction downstream-side
thermistor 214 which detects temperature changes in the vicinity
downstream in the refrigerant flow direction of the accumulation
tube F having the magnetic tube F2, as shown in FIG. 22, for
example; and detecting temperature changes is not limited to
detecting the temperature of the accumulation tube F.
[0179] (B)
[0180] In the embodiment described above, an example was described
of a case in which the state of attachment of the electromagnetic
induction thermistor 14 is confirmed to be satisfactory by
detecting a change in the detected temperature of the
electromagnetic induction thermistor 14 resulting from the
electromagnetic induction heating unit 6 being changed from a
stopped state to creating a magnetic field.
[0181] However, the present invention is not limited to this
example.
[0182] For example, the state of attachment of the electromagnetic
induction thermistor 14 may be confirmed by changing the
electromagnetic induction heating unit 6 from a state of creating a
magnetic field to a state of not creating a magnetic field. In this
case, the state of attachment of the electromagnetic induction
thermistor 14 can be confirmed to be satisfactory by detected
temperature changes in which the detected temperature of the
electromagnetic induction thermistor 14 decreases.
[0183] The state of attachment of the electromagnetic induction
thermistor 14 may also be confirmed merely by changing the
electricity supplied to the coil 68 of the electromagnetic
induction heating unit 6, thereby varying the strength of the
magnetic field being created, and by finding the resulting change
in the detected temperature of the electromagnetic induction
thermistor 14.
[0184] (C)
[0185] In the embodiment described above, an example was described
of a case in which a determination is made as to whether or not the
state of attachment of the electromagnetic induction thermistor 14
is satisfactory, focusing on changes in the detected temperature of
the electromagnetic induction thermistor 14 which detects the
temperature of the magnetic tube F2 constituting the outer side of
the accumulation tube F.
[0186] However, the present invention is not limited to this
example.
[0187] In another option, for example, temperature changes in the
accumulation tube F may be detected by using a detection device of
bimetal or the like for detecting if the temperature is greater
than a predetermined temperature or less than a predetermined
temperature, and setting the predetermined temperature of the
detection device to a value between the temperature prior to the
sensor-separation detection process and the subsequent temperature.
In this case, even if it is not possible to detect the specific
temperature when the sensor-separation detection process is
performed, the state of attachment of the sensor can be confirmed
by detecting the temperature changes.
[0188] (D)
[0189] In the embodiment described above, an example was described
of a case in which the output of the electromagnetic induction
heating unit 6 for electromagnetic induction heating is fixed at
70% in the steady output process while the output frequency thereof
is controlled.
[0190] However, the present invention is not limited to this
example.
[0191] For example, in the steady output process, the output of the
electromagnetic induction heating unit 6 may be controlled based on
the detected temperature of the electromagnetic induction
thermistor 14 while the frequency of performing electromagnetic
induction heating remains fixed.
[0192] Another option is for both the frequency of performing
electromagnetic induction heating and the output of the
electromagnetic induction heating unit 6 to be controlled based on
the detected temperature of the electromagnetic induction
thermistor 14 in the steady output process.
[0193] (E)
[0194] In the embodiment described above, an example was described
of a case in which the electromagnetic induction heating unit 6 is
attached to the accumulation tube F within the refrigerant circuit
10.
[0195] However, the present invention is not limited to this
example.
[0196] For example, the electromagnetic induction heating unit 6
may be provided to a refrigerant tube other than the accumulation
tube F. In this case, the magnetic tube F2 or another magnetic
component is provided to the refrigerant tube portion where the
electromagnetic induction heating unit 6 is provided.
[0197] (F)
[0198] In the embodiment described above, an example was described
of a case in which the accumulation tube F is configured as a
double-layer pipe comprising the copper tube F1 and the magnetic
tube F2.
[0199] However, the present invention is not limited to this
example.
[0200] For example, a magnetic member F2a and two stoppers F1a, F1b
may be disposed inside the accumulation tube F or a refrigerant
tube as a heated object, as shown in FIG. 23. The magnetic member
F2a is a member containing a magnetic material whereby heat is
generated by electromagnetic induction heating in the embodiment
described above. The stoppers F1a, F1b are placed in two locations
inside the copper tube F1, constantly allowing refrigerant to pass
through but not allowing the magnetic member F2a to pass through.
The magnetic member F2a thereby does not move despite the flow of
refrigerant. Therefore, the intended heating position in the
accumulation tube F or the like can be heated. Furthermore, since
the heat-generating magnetic member F2a and the refrigerant are in
direct contact, heat transfer efficiency can be improved.
[0201] (G)
[0202] The magnetic member F2a described in the other embodiment
(F) above may be positioned within the tube without the use of the
stoppers F1a, F1b.
[0203] For example, bent portions FW may be provided in two
locations in the copper tube F1, and the magnetic member F2a may be
disposed inside the copper tube F1 between these two bent portions
FW, as shown in FIG. 24. The movement of the magnetic member F2a
can be suppressed while refrigerant is allowed to pass through in
this manner as well.
[0204] (H)
[0205] In the embodiment described above, an example was described
of a case in which the coil 68 is wound around the accumulation
tube F in a helical formation.
[0206] However, the present invention is not limited to this
example.
[0207] For example, a coil 168 wound around a bobbin main body 165
may be disposed around the periphery of the accumulation tube F
without being wound over the accumulation tube F, as shown in FIG.
25. The bobbin main body 165 is disposed so that its axial
direction is substantially perpendicular to the axial direction of
the accumulation tube F. The bobbin main body 165 and the coil 168
are disposed in two separate parts so as to sandwich the
accumulation tube F.
[0208] In this case, for example, a first bobbin cover 163 and a
second bobbin cover 164 which pass through the accumulation tube F
may be arranged in a state of being fitted over the bobbin main
body 165, as shown in FIG. 26.
[0209] Furthermore, the first bobbin cover 163 and the second
bobbin cover 164 may be fixed in place by being sandwiched by a
first ferrite case 171 and a second ferrite case 172, as shown in
FIG. 27. In FIG. 27, an example is shown of a case in which two
ferrite cases are arranged so as to sandwich the accumulation tube
F, but they may be arranged in four directions similar to the
embodiment described above. The ferrite may also be accommodated
similar to the embodiment described above.
[0210] <Other>
[0211] Embodiments of the present invention were described above in
several examples, but the present invention is not limited to these
embodiments. For example, the present invention also includes
combined embodiments obtained by suitably combining different
portions of the above embodiments, within a range that can be
carried out based on the above descriptions by those skilled in the
art.
INDUSTRIAL APPLICABILITY
[0212] According to the present invention, performance during
startup can be quickly ensured while overshooting after startup can
be kept to a minimum; therefore, the present invention is
particularly useful in an electromagnetic induction heating unit
and an air conditioning apparatus in which refrigerant is heated
using electromagnetic induction.
REFERENCE SIGNS LIST
[0213] 1 Air conditioning apparatus [0214] 6 Electromagnetic
induction heating unit [0215] 10 Refrigerant circuit [0216] 11
Control part [0217] 14 Electromagnetic induction thermistor
(refrigerant state quantity detector, temperature detector) [0218]
15 Fuse [0219] 16 Plate spring (elastic member) [0220] 17 Plate
spring (elastic member) [0221] 21 Compressor [0222] 22 Four-way
switching valve [0223] 23 Outdoor heat exchanger [0224] 24 Electric
expansion valve [0225] 25 Accumulator [0226] 29a Pressure sensor
(refrigerant state quantity detector) [0227] 29b Outdoor air
temperature sensor [0228] 29c Outdoor heat exchange temperature
sensor [0229] 41 Indoor heat exchanger [0230] 43 Indoor temperature
sensor [0231] 44 Indoor heat exchange temperature sensor [0232] 65
Bobbin main body [0233] 68 Coil (magnetic field generator) [0234]
71-74 First ferrite case-fourth ferrite case [0235] 75 Shielding
cover [0236] 90 Controller [0237] 95 Timer [0238] 98, 99 First
ferrite, second ferrite [0239] F Accumulation tube, refrigerant
tube (predetermined state quantity detected portion) [0240] F2
Magnetic tube (heating target portion) [0241] M1
Separated-detection supply of electricity (magnetic field level)
[0242] M2 Steadily supplied electricity (first magnetic field limit
reference value) [0243] Mmax Maximum supplied electricity
(predetermined maximum output) [0244] Ph Target high pressure
(first predetermined target state quantity)
CITATION LIST
Patent Literature
[0244] [0245] <Patent Literature 1> Japanese Laid-open Patent
Application Publication No. 2000-97510
* * * * *