BACKGROUND
[0001] The present disclosure relates to an air conditioner and a method for controlling
the air conditioner. In general, an air conditioner refers to an appliance, for example
a home appliance, to maintain the optimum condition of indoor air according to use
and purpose. For instance, the air conditioner may cool the air in summer while heating
the air in winter. Also, the air conditioner may control the indoor humidity to thereby
maintain freshness of the indoor air.
[0002] As convenience products, such as the air conditioner, are getting more prevalent,
consumers' demands have been growing for more energy-efficient, high-functional and
user-friendly products.
[0003] The air conditioner may be classified into a split air conditioner in which an indoor
unit and an outdoor unit are separated from each other, and an integral air conditioner
in which an indoor unit and an outdoor unit are combined as one module. According
to an installation type, on the other hand, the air conditioner may be classified
into a wall mount air conditioner and a picture frame air conditioner to be hung on
the wall, and a slim air conditioner to be stood on a floor.
[0004] More specifically, the split air conditioner includes an indoor unit that is installed
indoors to supply warm air or cold air into a space being air-conditioned, and an
outdoor unit that compresses and expands refrigerant to facilitate the heat exchange
in the indoor unit.
[0005] During a heating mode of a heating and cooling air conditioner of the related art,
if it is determined using a temperature sensor that frost is formed on a surface of
an outdoor heat exchanger, the frost is removed by lowering the frequency of an inverter
compressor and switching a 4-way valve to temporarily drive a refrigeration cycle.
[0006] In such a method, however, an indoor heat exchanger has to operate as an evaporator
for defrosting in a cooling mode, which decreases the indoor temperature.
[0007] Furthermore, when the air conditioner is converted to the cooling mode, defrost may
be retarded since it takes a predetermined time for high-temperature refrigerant to
reach the outdoor heat exchanger.
SUMMARY
[0008] Embodiments provide an air conditioner improved in the structure and a control method
for efficient defrosting and heating, and a method for controlling the air conditioner.
[0009] Embodiments also provide an air conditioner capable of sensing quantity of frost
formed at a heat exchanger and accordingly varying heat quantity of an induction heater,
a method for controlling the same.
[0010] In one embodiment, an air conditioner includes: a compressor that compresses refrigerant
an indoor heat exchanger in which heat exchange between the refrigerant passed through
the compressor and indoor air is performed, an expansion device that decompresses
the refrigerant passed through the indoor heat exchanger, an outdoor heat exchanger
in which heat exchange between the refrigerant supplied from the expansion device
and outdoor air is performed, a plurality of sensors that sense temperature of the
outdoor heat exchanger, indoor temperature, and outdoor temperature, respectively,
a heater that generates heat variably according to the outdoor temperature and the
outdoor heat exchanger temperature detected by the sensors, and a controller that
determines quantity of frost formed on the outdoor heat exchanger by comparing a preset
reference temperature (or reference value) with a temperature difference between the
outdoor temperature and the outdoor heat exchanger temperature, and controls output
of the heater according to the determined frost quantity.
[0011] In another embodiment, a method for controlling an air conditioner comprising a compressor,
an indoor heat exchanger, an expansion device and an outdoor heat exchanger for a
refrigeration cycle, includes: comparing indoor temperature with a first preset temperature,
comparing outdoor temperature with a second preset temperature according to a result
of the comparison between the indoor temperature and the first preset temperature,
determining a temperature difference between the outdoor temperature and temperature
of an outdoor heat exchanger, comparing the temperature difference with a preset reference
temperature (or reference value) and controlling heat quantity of a heater that defrosts
the outdoor heat exchanger, according to a result of the comparison between the temperature
difference and the reference temperature.
[0012] In further another embodiment, a control method for an air conditioner comprising
a compressor, a condenser, an expansion device and an evaporator that are used for
driving a refrigeration cycle, and a heater to defrost the evaporator, includes: comparing
indoor and outdoor temperatures with preset temperatures, detecting a pipe temperature
of an outdoor heat exchanger, obtaining a temperature difference between the outdoor
temperature and temperature of the outdoor heat exchanger, determining frost quantity
on the evaporator by the temperature difference, and controlling heat quantity of
the heater in proportion to the frost quantity.
[0013] The details of one or more embodiments are set forth in the accompanying drawings
and the description below. Other features will be apparent from the description and
drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
Fig. 1 is a view showing the structure of a heating cycle of an air conditioner according
to an embodiment.
Fig. 2 is a block diagram showing the structure of the air conditioner according to
the embodiment.
Figs. 3 and 4 are flowcharts illustrating a method of controlling the air conditioner
in a first range of the indoor temperature; and
Fig. 5 is a flowchart illustrating a method of controlling the air conditioner in
a second range of the indoor temperature.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0015] Fig. 1 is a view showing the structure of a heating cycle of an air conditioner 1
according to an embodiment.
[0016] Referring to Fig. 1, the air conditioner 1 of the current embodiment includes a compressor
10 that compresses refrigerant, an indoor heat exchanger 21 in which high-temperature
high-pressure refrigerant compressed in the compressor 10 is supplied for heat exchange
with indoor air, an indoor heat exchanger fan 22 supplying the air heated through
the heat exchange into an indoor space, an expansion device (for example, a capillary
tube 30) that expands the refrigerant to a low pressure after the heat exchange, an
outdoor heat exchanger 41 in which heat exchange between the expanded refrigerant
and outdoor air is performed, and an outdoor heat exchanger fan 42 supplying the air
cooled through the heat exchange to the outside.
[0017] More particularly, for the operation of the heating cycle of the air conditioner,
the indoor heat exchanger 21 operates as a condenser to condense at low temperature
the refrigerant compressed in the compressor 10 whereas the outdoor heat exchanger
41 operates as an evaporator to evaporate the refrigerant decompressed and condensed
through the capillary tube 30.
[0018] Here, the refrigerant circulating during the heating cycle has a high pressure before
passing through the capillary tube 30 and has a low pressure after passing through
the capillary tube 30. Hereinafter, the refrigerant before passage through the capillary
tube 30 will be referred to as 'high-pressure side refrigerant' while the refrigerant
after passage through the capillary tube 30 will be referred to as 'low-pressure side
refrigerant'.
[0019] An indoor heat exchanger heater 23 is provided at one side of the indoor heat exchanger
21. The indoor heat exchanger heater 23 may supplement the heating capability of the
indoor heat exchanger 21, which may be decreased when the outside temperature is too
low owing to the configuration of the heating cycle.
[0020] Also, the indoor heat exchanger heater 23 is capable of maintaining a predetermined
temperature of the conditioned air blown to the indoor space during a 'defrosting
with continuous heating' operation.
[0021] The 'defrosting with continuous heating' operation is herein defined as the operation
in which a defrosting operation for the outdoor heat exchanger 41 is performed simultaneously
with a heating operation of the air conditioner. The defrosting operation for the
outdoor heat exchanger 41 may be performed as high-temperature high-pressure refrigerant
passed through the compressor 10 is bypassed toward an inlet of the outdoor heat exchanger
41.
[0022] A gas liquid separator 50 is disposed at an outlet of the outdoor heat exchanger
41. The gas liquid separator 50 extracts liquid refrigerant from the entire refrigerant
evaporated through the outdoor heat exchanger 41, and guides only gaseous refrigerant
into the compressor 10.
[0023] Additionally, the air conditioner 1 further includes a bypass path 81 that bypasses
hot gas of the refrigerant passed through the compressor 10 toward at least one of
the inlet of the outdoor heat exchanger 41 and an inlet of the gas liquid separator
50. More specifically, the bypass path 81 may extend from an outlet of the compressor
10 to the inlet of the outdoor heat exchanger 41 and to the inlet of the compressor
10.
[0024] The bypass path 81 includes a first valve 80 that controls quantity of the bypassing
refrigerant. The first valve 80 may include a solenoid valve.
[0025] As the refrigerant passed through the compressor 10 is bypassed to the inlet of the
compressor 10, the evaporating temperature and pressure of the refrigerant at the
inlet of the compressor 10 may be increased, thereby reducing a work input (load)
of the compressor 10. Moreover, imbalance of capacities between the compressor 10
and the indoor heat exchanger 21 may be reduced, accordingly improving the heating
efficiency.
[0026] In addition, the outdoor heat exchanger 41 may be defrosted by bypassing the high-temperature
high-pressure refrigerant passed through the compressor 10 to the inlet of the outdoor
heat exchanger 41.
[0027] In other words, the defrosting with continuous heating operation is carried out as
the refrigerant is bypassed by the first valve 80.
[0028] A second valve 90 is disposed on the bypass path 81 to prevent the refrigerant from
flowing from the inlet of the outdoor heat exchanger 41 to the inlet of the gas liquid
separator 50. In a general heating mode, the second valve 90 may prevent backflow
of the refrigerant from the inlet of the outdoor heat exchanger 41 to the inlet of
the gas liquid separator 50 through the bypass path 81. Here, the second valve 90
may include a check valve.
[0029] A 4-way valve 70 is disposed near the outlet of the compressor 10 in order to change
a flow direction of the refrigerant according to whether the air conditioner is in
a heating mode or a cooling mode.
[0030] In the heating mode, the refrigerant passed through the outdoor heat exchanger 41
is guided into the compressor 10 through the 4-way valve 70 and then compressed. The
compressed refrigerant is passed through the 4-way valve 70 and guided into the indoor
heat exchanger 21. On the other hand, in the cooling mode, the refrigerant passed
through the indoor heat exchanger 21 is guided into the compressor 10 through the
4-way valve 70 and then compressed. The compressed refrigerant may be guided into
the outdoor heat exchanger 41 through the outdoor heat exchanger 41.
[0031] A heater, such as an induction heater 60, is provided at the outside of the gas liquid
separator 50 to heat the refrigerant in the gas liquid separator 50. The induction
heater 60 may be configured to enclose an outer circumference of the gas liquid separator
50.
[0032] Specifically, the induction heater 60 is a heater that uses an induced current generated
by a magnetic field as a heat source. The induction heater 60 includes an electromagnet
that conducts a high-frequency alternating current. The electromagnet includes coils
conducting alternating currents.
[0033] The induction heater 60 supplies heat to the low-pressure side refrigerant, that
is, the refrigerant at the outdoor heat exchanger 41 during the defrosting with continuous
heating operation, consequently increasing the evaporating temperature of the refrigerant.
In addition, defrost for the outdoor heat exchanger 41 may be promoted.
[0034] Also, the induction heater 60 heats the refrigerant at the inlet of the compressor
10. Therefore, the induction heater 60 supplies heat to the high-pressure side refrigerant,
that is, the refrigerant at the indoor heat exchanger 21, and thereby increases a
condensing temperature. Thus, the evaporating temperature and the condensing temperature
of the refrigerant are increased, and therefore the heating efficiency and the defrosting
efficiency may both be improved.
[0035] Furthermore, the induction heater 60 supplies heat to the indoor heat exchanger 21
in the general heating mode, thereby increasing a pipe temperature of the indoor heat
exchanger 21. As a result, the air to be blown into the indoor space may be rapidly
heated.
[0036] An inverter system may be applied to the induction heater 60 to control the heat
quantity of the induction heater 60. In this case, the supplied heat quantity is adjustable
according to the outdoor temperature and the temperature of a heat exchanger requiring
defrosting. A method of controlling the heat quantity of the induction heater 60 according
to frost quantity on the outdoor heat exchanger 41 will be described hereinafter with
reference to the accompanying drawings.
[0037] Fig. 2 is a block diagram showing the structure of the air conditioner according
to the embodiment.
[0038] Referring to Fig. 2, the air conditioner 1 includes an outdoor temperature sensor
110 detecting the outdoor temperature, an indoor temperature sensor 120 detecting
temperature of an indoor space, and an outdoor heat exchanger sensor 130 detecting
a refrigerant pipe temperature of the outdoor heat exchanger 41.
[0039] The air conditioner 1 further includes a controller 100 that receives signals from
the sensors 110, 120 and 130 and controls the induction heater 60 which generates
heat by variable degrees according to values detected by the sensors 110, 120 and
130.
[0040] For a convenient explanation, the outdoor temperature sensor 110, the indoor temperature
sensor 120, and the outdoor heat exchanger sensor 130 will be referred to as a first
temperature sensor, a second temperature sensor, and a third temperature sensor, respectively.
[0041] More particularly, values detected by the sensors 110, 120 and 130 are transmitted
to the controller 100. The controller 100 may analyze data transmitted from the sensors
110, 120 and 130 and control the induction heater 60 to generate a preset quantity
of heat.
[0042] Hereinafter, an "outdoor temperature - outdoor heat exchanger pipe temperature" value
(a temperature difference) may be referred to as "GAP." In addition, quantities of
heat generated from the induction heater 60 may be classified into P1, P2 and P3.
However, more various quantities of heat output may be applied according to the control
method of the induction heater 60.
[0043] Fig. 3 and Fig. 4 are flowcharts illustrating a method of controlling the air conditioner
in a first indoor temperature range. Fig. 5 is a flowchart illustrating a method of
controlling the air conditioner in a second indoor temperature range.
[0044] The control method of the air conditioner according to the embodiment will now be
explained with reference to Fig. 3 to Fig. 5. The flowcharts of Fig. 3 to Fig. 5 show
the control method during the defrosting with continuous heating operation.
[0045] More specifically, Figs. 3 and 4 show a method of controlling the induction heater
according to the outdoor temperature and the outdoor heat exchanger pipe temperature
in a case where the indoor temperature is not less than a preset temperature T1 (preset
indoor reference temperature). Fig. 5 shows the control method in a case where the
indoor temperature is less than T1.
[0046] T1 may be preset to about 15°C, but is not limited thereto. That is, T1 may be varied
according to the control method of the air conditioner.
[0047] First, the indoor temperature is detected by the indoor temperature sensor 120 (S11).
When the indoor temperature is not less than T1, the outdoor temperature is detected
by the outdoor temperature sensor 110, and it is determined whether the outdoor temperature
is greater than a preset temperature T2 (S12, S13, and S14). The preset temperature
T
2 may also be referred to as a preset outdoor reference temperature.
[0048] Here, T2 may be set to about 0°C, but not limited thereto. That is, T2 may be varied
according to the control method of the air conditioner.
[0049] The quantity of frost (or a parameter indicative of the amount of frost) formed on
the outdoor heat exchanger 41 is determined when the outdoor temperature is not less
than T2 (S15). The frost quantity on the outdoor heat exchanger 41 may be determined
based on whether the "GAP" (outdoor temperature-outdoor heat exchanger pipe temperature)
is greater than a preset temperature difference H1. As the GAP becomes greater, condensed
air quantity at the pipe of the outdoor heat exchanger 41 may increase. Consequently,
frost is more likely to form on the pipe.
[0050] More particularly, temperature of the refrigerant pipe of the outdoor heat exchanger
41 is detected by the outdoor heat exchanger sensor 130. Next, the controller 100
determines the GAP, that is, a difference between the outdoor temperature and the
refrigerant pipe temperature. The difference is compared to H1.
[0051] Here, H1 may be preset to about 8°C, but not limited thereto. That is, H1 may be
varied according to the control method of the air conditioner (S16).
[0052] When the GAP is greater than H1, the controller 100 determines that the frost quantity
on the outdoor heat exchanger 41 is large. According to this, the controller 100 controls
the output of the induction heater 60 to a first output P1 so that the heat quantity
of the induction heater 60 is increased. P1 may be preset to about 1200W (S20).
[0053] When the GAP is greater than a preset temperature difference H2 and not greater than
H1, the controller 100 determines that the frost quantity on the outdoor heat exchanger
41 is medium and, accordingly, controls the output of the induction heater 60 to a
second output P2.
[0054] Here, H2 may be preset to 4°C different from H1. P2 may be preset to 900W less than
P1. However, not limited to those values, H2 and P2 values may be varied according
to the control method of the air conditioner (S17 and S19).
[0055] On the other hand, when the GAP is determined to be less than H2, the controller
100 determines that the frost quantity on the outdoor heat exchanger 41 is small.
According to this, the controller 100 may control the output of the induction heater
60 to a third output P3 so that the heat quantity of the induction heater 60 is reduced.
[0056] Here, P3 may be preset to about 600W. However, P3 may be set to any other value as
long as less than P2, according to the control method of the air conditioner (S18).
[0057] When the outdoor temperature is not greater than T2 in operation S14, it is determined
whether the outdoor temperature is greater than a preset temperature T3 and not greater
than T2 as shown in Fig. 4 (S21). Here, T3 may be set to about -5°C, but not limited
to this, may be varied according to the control method.
[0058] When the outdoor temperature is greater than T3 and not greater than T2, the frost
quantity on the outdoor heat exchanger 41 is determined (S22). The frost quantity
may be determined by whether the GAP is greater than a preset temperature difference
H3.
[0059] More specifically, the refrigerant pipe temperature of the outdoor heat exchanger
41 is detected by the outdoor heat exchanger sensor 130. The controller 100 determines
the GAP through the outdoor temperature and the refrigerant pipe temperature of the
outdoor heat exchanger 41. The GAP is compared to the H3 (S23).
[0060] Here, H3 may be preset to about 6°C which is different from H1 and H2 values. H3
may be varied according to the control method of the air conditioner.
[0061] When the GAP is greater than H3, the controller 100 may determine that the frost
quantity on the outdoor heat exchanger 41 is large and accordingly control the output
of the induction heater 60 to the first output P1 so that the heat quantity of the
induction heater 60 is increased (S20).
[0062] When the GAP is greater than a preset temperature difference H4 and not greater than
H3 (S24), the controller 100 may determine the frost quantity on the outdoor heat
exchanger 41 is medium and accordingly control the output of the induction heater
60 to the second output P2 (S19).
[0063] Here, H4 may be preset to about 3°C, but not limited thereto. That is, H4 may be
varied according to the control method of the air conditioner.
[0064] On the other hand, when the GAP is determined to be less than H4 (S24), the controller
100 may determine that the frost quantity on the outdoor heat exchanger 41 is small
and, accordingly, control the output of the induction heater 60 to the third output
P3 so that the heat quantity of the induction heater 60 is reduced (S18).
[0065] The frost quantity may be determined when the outdoor temperature is not greater
than T3 in operation S21 (S25). The frost quantity may be determined based on whether
the GAP is greater than a preset temperature difference H5. Here, H5 may be preset
to about 7°C, but not limited thereto. That is, H5 may be varied according to the
control method of the air conditioner.
[0066] When the GAP is greater than H5 (S26), the controller 100 determines that the frost
quantity on the outdoor heat exchanger 41 is large and accordingly control the output
of the induction heater 60 to the first output P1 so that the heat quantity of the
induction heater 60 is increased (S20).
[0067] When the GAP is not greater than H5 (S24), the controller 100 may determine the frost
quantity on the outdoor heat exchanger 41 is medium and accordingly control the output
of the induction heater 60 to the second output P2 (S19).
[0068] When the GAP is in a predetermined range, as the outdoor temperature decreases, the
frost quantity generally increases, thereby requiring more heat quantity for defrosting.
Therefore, when the outdoor temperature is not greater than T3, the output heat quantity
of the induction heater 60 may be maintained not less than P2.
[0069] When the indoor temperature is less than T1 in operation S12, the outdoor temperature
value is determined as shown in Fig. 5 (S31). More particularly, the outdoor temperature
is detected by the outdoor temperature sensor 110. The controller 100 determines whether
the detected outdoor temperature is greater than T2 (S32). As described above, T2
may be preset to about 0°C.
[0070] When the outdoor temperature is greater than T2, the frost quantity on the outdoor
heat exchanger 41 is determined. Here, the frost quantity is determined by whether
the GAP is greater than a preset temperature difference H6 (S32 and S33).
[0071] H6 may be set to about 7°C, but not limited to this. That is, H6 may be varied according
to the control method.
[0072] When the GAP is greater than H6 (S34), the controller 100 may determine that the
frost quantity on the outdoor heat exchanger 41 is large and accordingly control the
output of the induction heater 60 to the first output P1 so that the heat quantity
of the induction heater 60 is increased (S20).
[0073] On the other hand, when the GAP is not greater than H6 (S34), the controller 100
may determine that the frost quantity on the outdoor heat exchanger 41 is medium and
accordingly control the output of the induction heater 60 to the second output P2
(S19).
[0074] When the outdoor temperature is not greater than T2 in operation S32, it is determined
whether the outdoor temperature is greater than T3 and not greater than T2 (S37).
When the outdoor temperature is greater than the T3 and not greater than T2, the controller
100 determines the frost quantity (S38).
[0075] More specifically, the controller 100 determines whether the GAP is greater than
a preset temperature difference H7 (S39). Here, H7 may be preset to about 6°C, but
not limited to this, may be varied according to the control method.
[0076] When it is determined that the GAP is greater than H7, the controller 100 may determine
that the frost quantity on the outdoor heat exchanger 41 is large and, accordingly,
control the output of the induction heater 60 to the first output P1 so that the heat
quantity of the induction heater 60 is increased (S20).
[0077] On the other hand, when it is determined that the GAP is not greater than H7, the
controller 100 may determine that the frost quantity on the outdoor heat exchanger
41 is medium and, accordingly, control the output of the induction heater 60 to the
second output P2 (S19).
[0078] The frost quantity may be determined when the outdoor temperature is not greater
than T3 in operation S37 (S40). Here, the frost quantity may be determined by whether
the GAP is greater than a preset temperature difference H8. H8 may be preset to about
5°C, but not limited to this, may be varied according to the control method.
[0079] When the GAP is greater than H8 (S41), the controller 100 may determine that the
frost quantity on the outdoor heat exchanger 41 is large and, accordingly control
the output of the induction heater 60 to the first output P1 so that the heat quantity
of the induction heater 60 is increased (S20).
[0080] On the other hand, when the GAP is not greater than H8, the controller 100 may determine
that the frost quantity on the outdoor heat exchanger 41 is medium and, accordingly,
control the output of the induction heater 60 to the second output P2 (S19).
[0081] Under the condition of the same GAP value, the frost quantity increases as the indoor
temperature is low due to the structure of the refrigeration cycle. Accordingly, more
heat quantity is required to remove the frost. To this end, when the outdoor temperature
is not greater than T1, the output heat quantity of the induction heater 60 may be
maintained not less than P2.
[0082] In the above description, the H1 to H8 may be referred to as a "first reference temperature"
to "eighth reference temperature," respectively, as reference temperatures to determine
the GAP obtained through a calculation of "outdoor temperature-outdoor heat exchanger
pipe temperature." For example, H2 and H3 may be the second reference temperature
and the third reference temperature. As aforementioned, the first to the eighth reference
temperatures may be set to respectively different values in accordance with the indoor
temperature and the outdoor temperature.
[0083] For a convenient explanation, T1 serving as a reference to determine the indoor temperature
will be referred to as a "first preset temperature" while T2 and T3 serving as references
to determine the outdoor temperature will be referred to as "second preset temperatures."
Out of the second preset temperatures, T2 and T3 may be distinguished into a first
temperature and a second temperature.
[0084] According to the above-described embodiment, the GAP value to determine the frost
quantity on the outdoor heat exchanger may be differently set according to temperature
ranges including the indoor temperature and the outdoor temperature. Therefore, whether
the frost quantity is large or small may be determined by comparing the GAP value
to a temperature difference between the detected outdoor temperature and the outdoor
heat exchanger pipe temperature.
[0085] According to the above-described control method, the frost quantity may be accurately
determined under the condition of various indoor and outdoor temperatures and the
outdoor heat exchanger pipe temperature.
[0086] Furthermore, waste output of the induction heater may be prevented since the output
of the induction heater is varied based on whether the frost quantity on the outdoor
heat exchanger is large or small. As a result, the efficiency of power consumption
may be enhanced.
[0087] More specifically, the waste output of the induction heater can be prevented by increasing
the heat quantity of the induction heater when the frost quantity on the outdoor heat
exchanger is large and decreasing the heat quantity when the frost quantity is small.
[0088] As can be appreciated from the above description, the embodiment may improve the
indoor heating efficiency through the defrosting with continuous heating operation
during which heating and defrosting are simultaneously performed, also achieving defrost
of the outdoor heat exchanger.
[0089] Quantity of frost formed on the outdoor heat exchanger may be determined in accordance
with indoor and outdoor temperatures and the outdoor heat exchanger temperature. In
addition, heat quantity of the induction heater may be variably applied according
to the frost quantity determined. Therefore, waste of electricity can be reduced.
[0090] The induction heater provided to an accumulator reduces outward heat loss, also shortening
time for heat transfer from the induction heater to the refrigerant.
[0091] Furthermore, because heat of the induction heater is applied to the low-pressure
side refrigerant in the heating cycle during the heating operation, the heating efficiency
may be improved without the necessity of increasing output of the compressor.
[0092] Also, more heat may be transferred to the low-pressure side refrigerant by driving
the induction heater during the defrosting operation that removes frost from the evaporator.
As a result, the defrosting efficiency of the air conditioner may be improved.
1. An air conditioner (1) comprising:
a compressor (10) arranged to compress refrigerant;
an indoor heat exchanger (21) arranged to heat exchange between the refrigerant passed
through the compressor (10) and indoor air;
an expansion device (30) arranged to decompress the refrigerant passed through the
indoor heat exchanger (21);
an outdoor heat exchanger (41) arranged to heat exchange between the refrigerant supplied
from the expansion device (30) and outdoor air;
a plurality of sensors (110,130) arranged to sense temperature of the outdoor heat
exchanger and outdoor temperature, respectively;
a heater (60) arranged to generate heat variably according to the outdoor temperature
and the outdoor heat exchanger temperature detected by the sensors; and
a controller (100) arranged to determine a quantity indicative of the amount of frost
formed on the outdoor heat exchanger by comparing a reference temperature (H1) with
a temperature difference (GAP) between the outdoor temperature and the outdoor heat
exchanger temperature, and controls output of the heater (60) according to the determined
frost quantity.
2. The air conditioner according to claim 1, wherein the plurality of sensors comprise
an indoor temperature sensor (120) that detects indoor temperature, and the output
of the heater (60) is controlled according to whether the detected indoor temperature
is greater than a first preset temperature (T1).
3. The air conditioner according to any preceding claim, wherein the plurality of sensors
comprise an outdoor temperature sensor (110) that detects outdoor temperature, and
the output of the heater (60) is controlled according to whether the detected outdoor
temperature is greater than a second preset temperature (T2).
4. The air conditioner according to any preceding claim, wherein the output of the heater
(60) is increased in proportion to the difference (GAP) between the outdoor temperature
and the outdoor heat exchanger temperature.
5. The air conditioner according to any preceding claim, further comprising a gas liquid
separator (50) provided at an inlet of the compressor (10) to separate liquid refrigerant,
wherein the heater (60) comprises an induction heater provided for the gas liquid
separator.
6. The air conditioner according to any preceding claim, further comprising:
a bypass path (81) arranged to bypass the refrigerant from an outlet of the compressor
toward an inlet of the outdoor heat exchanger; and
a first valve (80) disposed on the bypass path (81) to control a flow of the refrigerant.
7. A method for controlling an air conditioner comprising a compressor (10), an indoor
heat exchanger (21), an expansion device (30), and an outdoor heat exchanger (41)
for a refrigeration cycle, the method comprising:
determining a temperature difference (GAP) between the outdoor temperature and a temperature
of an outdoor heat exchanger;
comparing the temperature difference (GAP) with a reference temperature (H1); and
controlling heat quantity of a heater (60) arranged to defrost the outdoor heat exchanger,
according to a result of the comparison between the temperature difference (GAP) and
the reference temperature (H1).
8. The method according to claim 7, further comprising:
comparing indoor temperature with a first preset temperature (T1); and
comparing outdoor temperature with a second preset temperature (T2) according to a
result of the comparison between the indoor temperature and the first preset temperature
(T1).
9. The method according to claim 8, wherein the reference temperature is set to different
values (H3,H7) according to whether the indoor temperature is not less than the first
preset temperature (T1).
10. The method according to claim 8 or 9, wherein the reference temperature is set to
different values (H1,H3) according to whether the outdoor temperature is not less
than the second preset temperature (T2).
11. The method according to any of claims 7 to 10, wherein the heat quantity of the heater
is increased when the temperature difference is greater than the reference temperature.
12. The method according to any of claims 7 to 11, wherein the heater (60) is adapted
to be controlled to provide a first output (P1), a second output (P2) less than the
first output, and a third output (P3) less than the second output, and
the heater is controlled to generate heat quantity of at least the second output (P2)
when the outdoor temperature is not greater than a second preset temperature (T2).
13. The method according to claim 12, wherein the heater is controlled to generate heat
quantity of at least the second output (P2) when the indoor temperature is less than
the first preset temperature.
14. The method according to claim 12, wherein the step of comparing against a reference
temperature includes comparing against a first reference temperature (H1) and a second
reference temperature (H2) which is less than the first reference temperature, and
under the condition where the outdoor temperature is greater than the second preset
temperature,
the heater outputs the first output (P1) when the temperature difference is greater
than the first reference temperature,
the heater outputs the second output (P2) when the temperature difference is greater
than the second reference temperature but not greater than the first reference temperature,
and
the heater outputs the third output (P3) when the temperature difference is not greater
than the second reference temperature.
15. The method according to any of claims 7 to 14, wherein, while an indoor space is heated
by the operation of the refrigeration cycle, defrosting of the outdoor heat exchanger
is simultaneously performed by bypassing refrigerant from an outlet of the compressor
(10) to an inlet of the outdoor heat exchanger (41).