BACKGROUND
[0001] The present disclosure relates to a refrigerator.
[0002] Refrigerators are home appliances for storing foods at a low temperature. For example,
a refrigerator includes a refrigerating compartment to store food in a refrigerated
state and a freezing compartment to store food in a frozen state.
[0003] Recently, demand for a refrigerator including a separate storage chamber for cooling
foods within a short time period to an ultralow temperature has increased. To achieve
the above-described objects, a separate deep-freezing storage chamber is provided
within a freezing compartment. Also, a structure is provided in which cool air within
a vaporizing chamber is independently supplied into the deep-freezing storage chamber
through a cool air passage connecting the deep-freezing storage chamber to the vaporizing
chamber. In the related art, since the cool air within the vaporizing chamber is separately
supplied into only the deep-freezing storage chamber, the deep-freezing storage chamber
may have a temperature lower than that of the freezing compartment without having
an influence on the temperatures of the freezing compartment and the refrigerating
compartment.
[0004] Generally, refrigerators use an R-600a isobutene refrigerant to lower a temperature
of an evaporator to a temperature of about -40°C to about -42°C. However, the deep-freezing
storage chamber may require a temperature lower than that of the evaporator, i.e.,
a temperature of about -50°C. To accomplish this, it may be insufficient to use only
the separate deep-freezing storage chamber.
[0005] To meet the demand of the deep-freezing cooling as described above, a suction pipe
connecting the evaporator to a compressor may exchange heat with an expansion valve.
Specifically, in the case where the suction pipe and the expansion valve exchange
heat to reduce an evaporation temperature, the refrigerant passing through the expansion
valve may further decrease in temperature to increase a heat absorption capacity,
thereby increasing a cooling ability. However, since an evaporation pressure itself
is not decreased, it may be difficult to decrease the evaporation temperature.
[0006] To solve the above-described limitation, an expansion valve having a smaller diameter
may be used. However, in this case, although the evaporation pressure is decreased,
a saturation achievement rate of the refrigerant may be further reduced when the evaporator
absorbs heat to lower the temperature of the deep-freezing storage chamber to a set
temperature. That is, the reduction in the saturation achievement rate of the refrigerant
represents the reduction in an amount of refrigerant which is saturated to generate
a gas by passing through the evaporator. Thus, an amount of liquid refrigerant introduced
into a gas/liquid separator is greater than that of gas refrigerant. As a result,
the possibility to introduce more liquid refrigerant into the compressor may be further
increased. Thus, a condensation pressure and an evaporation pressure in the whole
refrigeration cycle may be further increased. Furthermore, the introduction of liquid
refrigerant into the compressor may deteriorate performance of the compressor or damage
the compressor.
SUMMARY
[0007] One or more embodiments provide a refrigerator in which a temperature of a deep-freezing
storage chamber is further lowered than that of a deep-freezing storage chamber according
to the related art to minimize damage of a compressor, and provide a method for controlling
the same.
[0008] In one embodiment, a refrigerator including: a main body including a refrigerating
compartment maintained at a temperature higher than a freezing temperature and a freezing
compartment maintained at a temperature lower than the freezing temperature; a deep-freezing
storage chamber disposed within the main body, the deep-freezing storage chamber being
maintained at a temperature lower than that of the freezing compartment; a compressor
compressing a refrigerant at a high temperature and a high pressure; a condenser connected
to an outlet-side of the compressor to condense the high-temperature high-pressure
refrigerant; a first expansion valve connected to an outlet-side of the condenser
to expand the refrigerant so that the refrigerant has a low-temperature low-pressure
two-phase state; a first evaporator connected to an outlet-side of the first expansion
valve to change the refrigerant into a low-temperature low-pressure gas refrigerant;
and a heater disposed outside the first expansion valve, the heater supplying heat
into the first expansion valve to lower an evaporation temperature of the refrigerant
to a temperature lower than that of the freezing compartment.
[0009] 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 appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010]
Fig. 1 is a view illustrating a refrigeration cycle of a refrigerator according to
one embodiment.
Fig. 2 is a p-h diagram for comparing the refrigeration cycle according to one embodiment
to a general refrigeration cycle according to the related art.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0011] In the following detailed description of the preferred embodiments, reference is
made to the accompanying drawings which show by way of illustration specific preferred
embodiments in which the invention may be practiced. These embodiments are described
in sufficient detail to enable those skilled in the art to practice the invention,
and it is understood that other embodiments may be utilized. Logical, structural,
mechanical, electrical, and chemical changes may be made without departing from the
scope of the invention. To avoid detail not necessary to enable those skilled in the
art to practice the invention, the description may omit certain information known
to those skilled in the art. The following detailed description is, therefore, not
to be taken in a limiting sense, and the scope of the present disclosure is defined
only by the appended claims.
[0012] Hereinafter, a refrigerator and a method for controlling the refrigerator according
to one embodiment will be described in detail with reference to the accompanying drawings.
[0013] A refrigerator includes: a main body including a refrigerating compartment maintained
at a temperature higher than a freezing temperature and a freezing compartment maintained
at a temperature lower than the freezing temperature; a deep-freezing storage chamber
disposed within the main body, the deep-freezing storage chamber being maintained
at a temperature lower than that of the freezing compartment; a compressor compressing
a refrigerant at a high temperature and a high pressure; a condenser connected to
an outlet-side of the compressor to condense the high-temperature high-pressure refrigerant;
a first expansion valve connected to an outlet-side of the condenser to expand the
refrigerant so that the refrigerant has a low-temperature low-pressure two-phase state;
a first evaporator connected to an outlet-side of the first expansion valve to change
the refrigerant into a low-temperature low-pressure gas refrigerant; and a heater
disposed outside the first expansion valve, the heater supplying heat into the first
expansion valve to lower an evaporation temperature of the refrigerant to a temperature
lower than that of the freezing compartment.
[0014] The heater may contact an outer circumferential surface of the first expansion valve.
[0015] The compressor may include a linear compressor.
[0016] The first evaporator may be an evaporator used for cooling cool air supplied into
the deep-freezing storage chamber.
[0017] The refrigerator may further include at least one additional evaporator for cooling
one or all of the refrigerating compartment and the freezing compartment and at least
one additional expansion valve connected to an inlet-side of the at least one additional
evaporator.
[0018] The first expansion valve and the at least one additional expansion valve may be
connected in parallel to each other, and the refrigerator may further include a switching
valve disposed on a position at which the first and additional expansion valves are
branched to switch a flow direction of the refrigerant.
[0019] Fig. 1 is a view illustrating a refrigeration cycle of a refrigerator according to
one embodiment.
[0020] Referring to Fig. 1, a refrigeration cycle 10 of a refrigerator according to one
embodiment includes a compressor 11 compressing a refrigerant into a high-temperature
high-pressure gas state; a condenser 12 disposed on an outlet-side of compressor 11
to phase-change the high-temperature high-pressure gas refrigerant into a high-temperature
high-pressure liquid refrigerant; expansion valves 14 and 15 disposed on an outlet-side
of condenser 12 to expand the high-temperature high-pressure liquid refrigerant cooled
by passing through condenser 12, thereby changing the high-temperature high-pressure
liquid refrigerant into a low-temperature low-pressure two-phase refrigerant; and
evaporators 16 and 17 respectively disposed on outlet-sides of expansion valves 14
and 15 to phase-change the low-temperature low-pressure two-phase refrigerant which
is changed in phase by passing through expansion valves 14 and 15 into a low-temperature
low-pressure liquid refrigerant.
[0021] Specifically, compressor 11 may include a linear compressor. Alternatively, compressor
11 may include a fixed speed or inverter compressor. When compressor 11 includes a
linear compressor, compressor 11 is controlled so that a top dead center operation
is performed in a deep-freezing cooling process.
[0022] Generally, the condenser 12 may be accommodated in a machine room disposed in a rear
side of the refrigerator to release heat to the ambient air (e.g., indoor air). Also,
a switching valve 13 including a three-way valve may be disposed between condenser
12 and the expansion valves 14 and 15. Switching valve 13 is used for switching a
flow direction of the refrigerant in a structure in which main evaporator 16 is used
for cooling the refrigerating compartment, and the freezing compartment and deep-freezing
evaporator 17 is used for cooling the deep-freezing storage chamber and are connected
to parallel to each other. Here, the three-way valve or a four-way valve may be used
according to the number of evaporators. For example, when one main evaporator is used,
and thus a cool air passage connecting the refrigerating compartment to the freezing
compartment is switched to independently control a temperature of each of the storage
compartments, the three-way valve may be used. On the other hand, in a structure in
which an evaporator for the refrigerating compartment, an evaporator for the freezing
compartment, and an evaporator for the deep-freezing evaporator are separately provided
and connected parallel to each other, the four-way valve may be applied to switch
the flow direction of the refrigerant.
[0023] One exemplary embodiment in which one main evaporator 16 is used to cool the refrigerating
compartment and the freezing compartment, and a separate deep-freezing evaporator
17 is used for cooling the deep-freezing storage chamber and is parallely connected
to main evaporator 16 will be described. Thus, main expansion valve 15 and deep-freezing
expansion valve 14 may be respectively disposed on inlet-sides of the main evaporator
16 and the deep-freezing evaporator 17, and the expansion valves 14, 15 are connected
in parallel with each other at the outlet-side of the switching valve 13.
[0024] A separate heater 18 may be mounted on an outer circumferential surface of deep-freezing
expansion valve 14 to reduce a temperature of the refrigerant passing through deep-freezing
expansion valve 14 to a temperature lower than that of the freezing compartment. Heater
18 is operated in an operation mode for cooling the deep-freezing storage chamber.
When the deep-freezing storage chamber is cooled to a set temperature, the heater
18 may be stopped in operation.
[0025] Also, a condensation fan (not shown) and an evaporation fan (not shown) may be respectively
mounted outside condenser 12 and evaporators 16 and 17 to heat-exchange the indoor
air with the refrigerant or air within the storage chamber with the refrigerant.
[0026] Fig. 2 is a p-h diagram for comparing the refrigeration cycle according to an embodiment
to a general refrigeration cycle according to a related art.
[0027] Referring to Fig. 2, in the general refrigeration cycle according to the related
art, and compression, condensation, expansion, and evaporation are performed in an
order of points a, b, c, and d.
[0028] On the other hand, in the refrigeration cycle according to an embodiment of the present
disclosure, i.e., the refrigeration cycle including heater 18 on the outer circumferential
surface of deep-freezing expansion valve 14, compression, condensation, expansion,
and evaporation are performed in an order of points e, f, c, and g.
[0029] As shown in the p-h diagram, when heater 18 mounted on deep-freezing expansion valve
14 is driven, the refrigerant passing through deep-freezing expansion valve 14 may
be dropped to an evaporation pressure lower than that in the refrigerant cycle according
to the related art. Specifically, since the evaporation pressure is lowered, the evaporation
temperature is lowered. Thus, since the evaporation temperature is lowered, cool air
within the deep-freezing storage chamber may be lowered in temperature to less than
that of cool air according to the related art.
[0030] The general refrigeration cycle according to the related art in the p-h diagram of
Fig. 2 represents a cycle diagram when any heat-exchange member is not provided to
the expansion valve. In a case of a structure in which a suction pipe is heat-exchanged
with the expansion valve, heat may be transferred from the refrigerant passing through
the expansion valve to the refrigerant passing through the suction pipe, an amount
of gas refrigerant of the refrigerant introduced into the compressor may be increased.
Then, the refrigerant passing through the expansion valve may be decreased in temperature.
Thus, an enthalpy line (a c-d line) of the refrigerant may be further shifted to the
left in the p-h diagram. As a result, an enthalpy valve of the refrigerant at an inlet
of the evaporator may be decreased. That is, an amount of heat absorbed into the evaporator
may be increased to increase cooling capacity. However, although the heat exchange
may be performed through the suction pipe, since the evaporation pressure is not changed,
it may be difficult to further reduce the temperature of the cool air within the deep-freezing
storage chamber even though the cooling capacity is increased.
[0031] Also, in a case where the deep-freezing expansion valve has a diameter less than
that of the main expansion valve, a refrigerant state point (e.g., point d) when the
expansion is completed, i.e., an evaporation pressure at the inlet of the deep-freezing
evaporator may be further decreased, and also, an enthalpy valve at the deep-freezing
evaporator may be increased. That is, in the p-h diagram, the point d may be shifted
down and to the right. As a result, the refrigerant may be further decreased in temperature
to decrease the temperature of the deep-freezing storage chamber. However, due to
the decrease in the temperature of the deep-freezing storage chamber, an amount of
refrigerant which is changed in phase from the liquid refrigerant to the gas refrigerant
in the refrigerant passing through the evaporator may be reduced. That is, if it is
assumed that the refrigerant passing through the evaporator absorbs energy having
the same heat from the indoor air, an amount of refrigerant which is changed in phase
from the liquid refrigerant to the gas refrigerant may be reduced. This may represent
the reduction in a saturation achievement rate of the refrigerant. As a result, possibility
of the introduction of the liquid refrigerant into the compressor may be further increased.
[0032] As proposed in one embodiment, when heater 18 is mounted on the surface of deep-freezing
expansion valve 14, outlet point d of the deep-freezing expansion valve (or the outlet
point of the deep-freezing evaporator) may be moved to point g in an ideal state.
In an actual refrigeration cycle, point g may be located at a point that is further
shifted to the right.
[0033] If it is assumed that the evaporator absorbs the energy having the same heat, quality
of the refrigerant at the inlet of the compressor, i.e., quality of the refrigerant
at an inlet of a gas/liquid separator may be further increased in the current embodiment
when compared to the case in which the expansion valve is changed in diameter. This
may represent that the saturation achievement rate of the refrigerant is not reduced.
Thus, the possibility of the introduction of the liquid refrigerant into the compressor
may be significantly decreased.
[0034] As described above, since heater 18 provided in one embodiment is attached to deep-freezing
expansion valve 17, the evaporation temperature and pressure of the refrigerant passing
through deep-freezing expansion valve 17 may be significantly reduced when compared
to those of a refrigerant in the related art. Thus, the deep-freezing storage chamber
may be cooled to a temperature significantly lower than that of the freezing compartment.
That is to say, although a refrigerant passing through the expansion valve to which
the heater is not mounted is lowered to a temperature of about -40°C, the refrigerant
passing through the expansion valve to which the heater is mounted may be lowered
to a temperature of a maximum -50°C.
[0035] According to the method for controlling the refrigerator including the above-described
constitutions, the separate heater may be provided to the expansion valve connected
to the inlet-side of the evaporator for the deep-freezing storage chamber to further
decrease the evaporator pressure when compared to that in the related art. Thus, the
evaporator may be lowered up to a temperature of a maximum -50°C. In addition, the
deterioration in the saturation achievement rate of the refrigerant which occurs when
the expansion valve is changed in diameter may not occur, preventing the compressor
from being degraded in performance or damaged.
[0036] Although embodiments have been described with reference to a number of illustrative
embodiments thereof, it should be understood that numerous other modifications and
embodiments can be devised by those skilled in the art that will fall within the scope
of the principles of this disclosure. More particularly, variations and modifications
are possible in the component parts and/or arrangements of the subject combination
arrangement within the scope of the disclosure, the drawings and the appended claims.
In addition to variations and modifications in the component parts and/or arrangements,
alternative uses will also be apparent to those skilled in the art.
1. A refrigerator comprising:
a main body comprising a refrigerating compartment configured to be maintained at
a temperature higher than a freezing temperature and a freezing compartment configured
to be maintained at a temperature lower than the freezing temperature;
a deep-freezing storage chamber disposed within the main body, the deep-freezing storage
chamber being configured to be maintained at a temperature lower than that of the
freezing compartment;
a compressor (11) for compressing a refrigerant at a high temperature and a high pressure;
a condenser (12) connected to an outlet-side of the compressor to condense the high-temperature
high-pressure refrigerant;
a first expansion valve (14) connected to an outlet-side of the condenser to expand
the refrigerant so that the refrigerant has a low-temperature low-pressure two-phase
state;
a first evaporator (17) connected to an outlet-side of the first expansion valve to
change the refrigerant into a low-temperature low-pressure gas refrigerant; and
a heater (18) disposed outside the first expansion valve, for supplying heat into
the first expansion valve (14) to lower an evaporation temperature of the refrigerant
to a temperature lower than that of the freezing compartment.
2. The refrigerator of claim 1, wherein the heater (18) is disposed in such a manner
that the heater contacts an outer circumferential surface of the first expansion valve
(14).
3. The refrigerator of claim 1 or 2, wherein the compressor (11) comprises a linear compressor.
4. The refrigerator of any of claims 1 to 3, wherein the first evaporator (17) is configured
for cooling cool air supplied into the deep-freezing storage chamber.
5. The refrigerator of any of preceding claims, further comprising:
at least one additional evaporator (16) for cooling one or all of the refrigerating
compartment and the freezing compartment; and
at least one additional expansion valve (15) connected to an inlet-side of the at
least one additional evaporator.
6. The refrigerator of claim 5, wherein the first expansion valve (14) and the at least
one additional expansion valve (15) are connected in parallel to each other, and
the refrigerator further comprises:
a switching valve (13) disposed on a position at which the first and the at least
one additional expansion valves (14, 15) are branched, so as to switch a flow direction
of the refrigerant.