U.S. patent application number 13/128377 was filed with the patent office on 2011-09-15 for non-freezing storage unit and refrigerator including the same.
This patent application is currently assigned to LG Electronics, Inc.. Invention is credited to Hoon-Bong Lee, Sang-Ho Oh, Deok-Hyun Youn.
Application Number | 20110219805 13/128377 |
Document ID | / |
Family ID | 42310312 |
Filed Date | 2011-09-15 |
United States Patent
Application |
20110219805 |
Kind Code |
A1 |
Youn; Deok-Hyun ; et
al. |
September 15, 2011 |
NON-FREEZING STORAGE UNIT AND REFRIGERATOR INCLUDING THE SAME
Abstract
The present invention relates to a non-freezing storage unit
which can store food at a temperature below 0.degree. C. without
freezing the food, and a refrigerator including the same. The
non-freezing storage unit includes an outer casing with one open
surface, a drawer which can be pulled out and detached through the
open surface of the outer casing, a sensor located on one surface
of the outer casing and sensing a temperature of food located in
the drawer, a thermal conductive member installed on one surface of
the drawer facing the sensor and transferring the temperature of
the food in the drawer to the sensor, and a heater installed in the
outer casing. The non-freezing storage unit is located in a cooling
space to store food in a non-frozen state at a temperature below
0.degree. C.
Inventors: |
Youn; Deok-Hyun;
(Gyeongsangnam-do, KR) ; Oh; Sang-Ho; (Daegu,
KR) ; Lee; Hoon-Bong; (Gyeongsangnam-do, KR) |
Assignee: |
LG Electronics, Inc.
Seoul
KR
|
Family ID: |
42310312 |
Appl. No.: |
13/128377 |
Filed: |
December 10, 2009 |
PCT Filed: |
December 10, 2009 |
PCT NO: |
PCT/KR09/07393 |
371 Date: |
May 9, 2011 |
Current U.S.
Class: |
62/331 ;
219/439 |
Current CPC
Class: |
F25D 11/02 20130101;
F25D 2600/06 20130101; F25D 2400/02 20130101; F25D 2700/16
20130101 |
Class at
Publication: |
62/331 ;
219/439 |
International
Class: |
F25D 23/12 20060101
F25D023/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 30, 2008 |
KR |
10-2008-0137367 |
Dec 30, 2008 |
KR |
10-2008-0137369 |
Claims
1. A non-freezing storage unit, comprising: an outer casing with
one open surface; a drawer which can be pulled out and detached
through the open surface of the outer casing; a sensor located on
one surface of the outer casing and sensing a temperature of food
located in the drawer; a thermal conductive member installed on one
surface of the drawer facing the sensor and transferring the
temperature of the food in the drawer to the sensor; and a heater
installed in the outer casing, wherein the non-freezing storage
unit is located in a cooling space to store food in a non-frozen
state at a temperature below 0.degree. C.
2. The non-freezing storage unit of claim 1, wherein an insulation
material is filled in the outer casing.
3. The non-freezing storage unit of claim 1, wherein the thermal
conductive member comprises a metal plate located on a bottom
surface of the drawer and receiving a temperature change of the
food, and a contact point portion transferring the temperature
change between the metal plate and the sensor.
4. The non-freezing storage unit of claim 3, wherein the contact
point portion is downwardly protruded from the bottom surface of
the drawer.
5. The non-freezing storage unit of claim 1, wherein a handle for
use in pulling the drawer out is provided on one surface of the
drawer corresponding to the open surface of the outer casing.
6. The non-freezing storage unit of claim 5, wherein the handle
comprises a grip portion and a hook portion moved in cooperation
with the grip portion, and the outer casing comprises a hooked
portion on which the hook portion is hooked.
7. The non-freezing storage unit of claim 1, wherein a gasket for
use in sealing up the inner space is provided on one surface of the
drawer corresponding to the open surface of the outer casing.
8. The non-freezing storage unit of claim 1, wherein the outer
casing and the drawer comprise guide portions for guiding the
movement of the drawer, respectively, and the guide portions guide
the drawer so that the drawer can be located lower in the outer
casing than during the movement, when the drawer is completely
inserted into the outer casing.
9. The non-freezing storage unit of claim 8, wherein, when the
drawer is inserted into the outer casing and downwardly moved by
the guide portions, the sensor and the thermal conductive member
are brought into contact with each other.
10. The non-freezing storage unit of claim 1, further comprising a
fan installed in the outer casing and producing the flow of the air
in the unit.
11. The non-freezing storage unit of claim 1, wherein the heater
comprises an upper heater installed on an inside top surface of the
outer casing and a lower heater installed on an inside bottom
surface of the outer casing.
12. The non-freezing storage unit of claim 11, further comprising a
sensor for sensing a temperature in the unit which is installed at
an upper portion of the outer casing and senses a temperature of
the air in the drawer.
13. The non-freezing storage unit of claim 12, wherein a heating
value of the upper heater is adjusted according to the temperature
measured by the sensor for sensing the temperature in the unit, and
a heating value of the lower heater is adjusted according to the
temperature measured by the sensor.
14. The non-freezing storage unit of claim 12, wherein the heating
values of the upper heater and the lower heater are controlled so
that the temperature in the inside upper portion of the unit can be
higher than the temperature in the inside lower portion of the unit
by about 1 to 2.degree. C.
15. The non-freezing storage unit of claim 12, wherein at least one
of the upper heater and the lower heater comprises a plurality of
individual heaters, at least one of the plurality of individual
heaters is constantly operated, and the other individual heaters
are turned on/off according to the temperature in the unit.
16. The non-freezing storage unit of claim 1, further comprising a
side casing located on a side surface of the outer casing and
having a display portion and a button portion at the front.
17. The non-freezing storage unit of claim 16, further comprising a
control panel installed in the side casing, cooperating with the
display portion, the button portion and the sensor, and controlling
electric components in the unit.
18. The non-freezing storage unit of claim 1, wherein the heater is
a thermoelectric element having the flowing current and voltage
controlled to adjust the temperature in the non-freezing storage
unit.
19. A refrigerator comprising: a non-freezing storage unit as
recited claim 1; and a cooling space cooled by a freezing cycle and
having the non-freezing storage unit therein.
20. The refrigerator of claim 19, wherein a temperature in the
non-freezing storage unit is maintained at about -2.degree. C. to
-4.degree. C., raised to normal temperature when it is determined
that the food has been frozen on the basis of a food temperature
change sensed by a sensor, and lowered again to -2.degree. C. to
-4.degree. C. to store the food.
Description
TECHNICAL FIELD
[0001] The present invention relates to a non-freezing storage unit
which can store food at a temperature below 0.degree. C. without
freezing the food, and a refrigerator including the same.
BACKGROUND ART
[0002] Supercooling means the phenomenon that a molten object or a
solid is not changed although it is cooled to a temperature below a
phase transition temperature in an equilibrium state. A material
has a stable state at every temperature. If the temperature is
slowly changed, the constituent elements of the material can follow
the temperature changes, maintaining the stable state at each
temperature. However, if the temperature is suddenly changed, since
the constituent elements cannot be changed into the stable state at
each temperature, the constituent elements maintain a stable state
at an initial temperature, or some of the constituent elements fail
to be changed into a state at a final temperature.
[0003] For example, when water is slowly cooled, it is not
temporarily frozen at a temperature below 0.degree. C. However,
when water enters a supercooled state, it has a kind of
quasi-stable state. As this unstable equilibrium state is easily
broken even by slight stimulation, water tends to move into a more
stable state. That is, if a small piece of the material is put into
the supercooled liquid, or if the liquid is suddenly shaken, the
liquid starts to be frozen at once such that the temperature of the
liquid reaches the freezing point, and maintains a stable
equilibrium state at the temperature. In general, an electrostatic
atmosphere is made in a refrigerator, and meat and fish are thawed
in the refrigerator at a minus temperature. In addition to the meat
and fish, fruit is kept fresh in the refrigerator.
[0004] This technology uses a supercooling phenomenon. The
supercooling phenomenon indicates the phenomenon that a molten
object or a solid is not changed although it is cooled to a
temperature below a phase transition temperature in an equilibrium
state.
[0005] This technology includes Korean Patent Publication No.
2000-0011081 which discloses an electrostatic field processing
method, an electrostatic field processing apparatus, and electrodes
therefor.
[0006] FIG. 1 is a view of an example of a conventional thawing and
freshness-keeping apparatus. A keeping-cool room 1 is composed of
an insulation material 2 and an outer wall 5. A mechanism (not
shown) controlling a temperature inside the room 1 is installed
therein. A metal shelf 7 installed in the room 1 has a two-layer
structure.
[0007] Target objects to be thawed or freshness-kept and ripened
such as vegetables, meat and marine products are loaded on the
respective layers. The metal shelf 7 is insulated from the bottom
of the room 1 by an insulator 9. In addition, since a high voltage
generator 3 can generate 0 to 5000 V of DC and AC voltages, an
insulation plate 2a such as vinyl chloride, etc. is covered on the
inside of the insulation material 2. A high-voltage cable 4
outputting the voltage of the high voltage generator 3 is connected
to the metal shelf 7 after passing through the outer wall 5 and the
insulation material 2.
[0008] When a user opens a door installed at the front of the
keeping-cool room 1, a safety switch 13 (see FIG. 2) is turned off
to intercept the output of the high voltage generator 3.
[0009] FIG. 2 is a circuit view of the circuit configuration of the
high voltage generator 3. 100 V of AC is supplied to a primary side
of a voltage regulation transformer 15. Reference numeral 11
represents a power lamp and 19 a working state lamp. When the door
6 is closed and the safety switch 13 is on, a relay 14 is operated.
This state is displayed by a relay operation lamp 12. Relay contact
points 14a, 14b and 14c are closed by the operation of the relay
14, and 100 V of AC is applied to the primary side of the voltage
regulation transformer 15.
[0010] The applied voltage is regulated by a regulation knob 15a on
a secondary side of the voltage regulation transformer 15, and the
regulated voltage value is displayed on a voltmeter. The regulation
knob 15a is connected to a primary side of a boosting transformer
17 at the secondary side of the voltage regulation transformer 15.
The boosting transformer 17 boosts the voltage at a ratio of 1:50.
For example, when 60 V of voltage is applied, it is boosted to 3000
V.
[0011] One end O.sub.1 of the output of the secondary side of the
boosting transformer 17 is connected to the metal shelf 7 insulated
from the keeping-cool room 1 through the high-voltage cable 4, and
the other end O.sub.2 of the output is grounded. Moreover, since
the outer wall 5 is grounded, if the user touches the outer wall 5
of the keeping-cool room 1, he/she does not get an electric shock.
Further, in FIG. 1, when the metal shelf 7 is exposed in the room
1, it should be maintained in an insulated state in the room 1.
Thus, the metal shelf 7 needs to be separated from the wall of the
room 1 (the air performs an insulation function). Furthermore, if a
target object 8 is protruded from the metal shelf 7 and brought
into contact with the wall of the room 1, the current flows to the
ground through the wall of the room 1. Therefore, the insulation
plate 2a is attached to the inner wall to prevent drop of the
applied voltage. Still furthermore, when the metal shelf 7 is
covered with vinyl chloride without being exposed in the room 1, an
electric field atmosphere is produced in the entire room 1.
[0012] In the prior art, an electric field or magnetic field is
applied to the received object to be cooled such that the received
object reaches a supercooled state. Accordingly, a complicated
apparatus for producing the electric field or magnetic field should
be provided to keep the received object in the supercooled state,
and the power consumption is increased during the production of the
electric field or magnetic field. Additionally, the apparatus for
producing the electric field or magnetic field should further
include a safety device (e.g., an electric field or magnetic field
shielding structure, an interception device, etc.) for protecting
the user from high power, when producing or intercepting the
electric field or magnetic field.
DISCLOSURE
Technical Problem
[0013] An object of the present invention is to provide a
non-freezing storage unit in which a drawer can be completely
pulled out of an outer casing.
[0014] Another object of the present invention is to provide a
non-freezing storage unit which can maintain a received object in a
supercooled state via power supply in a space where only the
cooling is performed.
[0015] A further object of the present invention is to provide a
non-freezing storage unit which can selectively perform the
supercooled state control and the frozen state control on a
received object.
[0016] A still further object of the present invention is to
provide a non-freezing storage unit which can accomplish the
convenience of the reception of a received object and the accurate
sensing of a temperature of the received object.
[0017] A still further object of the present invention is to
provide a non-freezing storage unit in which a control unit
performing the supercooled state control and the frozen state
control is separated from a receiving space of a received object
and mounted on a side surface of the unit.
[0018] A still further object of the present invention is to
provide a temperature change room in which the cooling/heating can
be switched using a thermoelectric element, although an evaporator
is not additionally included in a refrigerator.
[0019] A still further object of the present invention is to
provide a temperature change room which can serve as a non-freezing
room which can store food in a non-frozen supercooled state by
adjusting a temperature of a thermoelectric element.
Technical Solution
[0020] According to an aspect of the present invention, there is
provided a non-freezing storage unit, including: an outer casing
with one open surface; a drawer which can be pulled out and
detached through the open surface of the outer casing; a sensor
located on one surface of the outer casing and sensing a
temperature of food located in the drawer; a thermal conductive
member installed on one surface of the drawer facing the sensor and
transferring the temperature of the food in the drawer to the
sensor; and a heater installed in the outer casing, wherein the
non-freezing storage unit is located in a cooling space to store
food in a non-frozen state at a temperature below 0.degree. C. In
addition, an insulation material is filled in the outer casing.
[0021] Moreover, the thermal conductive member includes a metal
plate located on a bottom surface of the drawer and receiving a
temperature change of the food, and a contact point portion
transferring the temperature change between the metal plate and the
sensor.
[0022] Further, the contact point portion is downwardly protruded
from the bottom surface of the drawer.
[0023] Furthermore, a handle for use in pulling the drawer out is
provided on one surface of the drawer corresponding to the open
surface of the outer casing. Still furthermore, the handle includes
a grip portion and a hook portion moved in cooperation with the
grip portion, and the outer casing includes a hooked portion on
which the hook portion is hooked.
[0024] Still furthermore, a gasket for use in sealing up the inner
space is provided on one surface of the drawer corresponding to the
open surface of the outer casing.
[0025] Still furthermore, the outer casing and the drawer include
guide portions for guiding the movement of the drawer,
respectively, and the guide portions guide the drawer so that the
drawer can be located lower in the outer casing than during the
movement, when the drawer is completely inserted into the outer
casing.
[0026] Still furthermore, when the drawer is inserted into the
outer casing and downwardly moved by the guide portions, the sensor
and the thermal conductive member are brought into contact with
each other.
[0027] Still furthermore, the non-freezing storage unit further
includes a fan installed in the outer casing and producing the flow
of the air in the unit.
[0028] Still furthermore, the heater includes an upper heater
installed on an inside top surface of the outer casing and a lower
heater installed on an inside bottom surface of the outer
casing.
[0029] Still furthermore, the non-freezing storage unit further
includes a sensor for sensing a temperature in the unit which is
installed at an upper portion of the outer casing and senses a
temperature of the air in the drawer.
[0030] Still furthermore, a heating value of the upper heater is
adjusted according to the temperature measured by the sensor for
sensing the temperature in the unit, and a heating value of the
lower heater is adjusted according to the temperature measured by
the sensor.
[0031] Still furthermore, the heating values of the upper heater
and the lower heater are controlled so that the temperature in the
inside upper portion of the unit can be higher than the temperature
in the inside lower portion of the unit by about 1 to 2.degree.
C.
[0032] Still furthermore, at least one of the upper heater and the
lower heater includes a plurality of individual heaters, at least
one of the plurality of individual heaters is constantly operated,
and the other individual heaters are turned on/off according to the
temperature in the unit.
[0033] Still furthermore, the non-freezing storage unit further
includes a side casing located on a side surface of the outer
casing and having a display portion and a button portion at the
front.
[0034] Still furthermore, the non-freezing storage unit further
includes a control panel installed in the side casing, cooperating
with the display portion, the button portion and the sensor, and
controlling electric components in the unit.
[0035] Still furthermore, the heater is a thermoelectric element
having the flowing current and voltage controlled to adjust the
temperature in the non-freezing storage unit.
[0036] Meanwhile, there is provided a refrigerator, including: a
non-freezing storage unit described above; and a cooling space
cooled by a freezing cycle and having the non-freezing storage unit
therein.
[0037] In addition, a temperature in the non-freezing storage unit
is maintained at about -2.degree. C. to -4.degree. C., raised to
normal temperature when it is determined that the food has been
frozen on the basis of a food temperature change sensed by a
sensor, and lowered again to -2.degree. C. to -4.degree. C. to
store the food.
Advantageous Effects
[0038] According to the temperature change room of the refrigerator
of the present invention, the temperature change room is
implemented using the thermoelectric element. Therefore, when it is
intended to store the food at a temperature lower than a
temperature in a refrigerating chamber, it is not necessary to
introduce the cool air of a freezing chamber into the temperature
change room. A damper or the like is not necessary, which
simplifies the structure of the refrigerator.
[0039] In addition, according to the temperature change room of the
refrigerator of the present invention, the heating can be performed
in the temperature change room using the thermoelectric element. It
is thus not necessary to install two or more evaporators to utilize
a heating function.
[0040] Moreover, according to the temperature change room of the
refrigerator of the present invention, the temperature in the
temperature change room can be adjusted regardless of the operation
conditions of the refrigerating chamber and the freezing
chamber.
[0041] Further, according to the non-freezing storage unit provided
by the present invention, the drawer can be completely detached
from the outer casing, which improves the convenience of the
use.
[0042] Furthermore, according to the non-freezing storage unit
provided by the present invention, the sensor is installed in the
outer casing and more sensitively senses the temperature of the
food. This improves the non-freezing stability and enables easy
determination on the release of the non-frozen state.
[0043] Still furthermore, according to the non-freezing storage
unit provided by the present invention, the operation panel and the
control panel irrelevant to the refrigerator are installed at one
side of the non-freezing storage unit to thereby easily control the
functions of the non-freezing storage unit.
[0044] Still furthermore, according to the non-freezing storage
unit provided by the present invention, the plurality of heaters
are provided to perform the non-freezing function. In a state where
one or more heaters are always in operation, the other heaters are
used to adjust the heating value. It is thus possible to reduce the
temperature fluctuation range in the non-freezing storage unit
influenced by the adjustment of the heating value of the heater. It
is also possible to reduce the influence on the sensor exerted by
the change in the heating value of the heater. This improves the
sensitivity of the sensor to the release of the non-frozen
state.
DESCRIPTION OF DRAWINGS
[0045] FIG. 1 is a view of an example of a conventional thawing and
freshness-keeping apparatus.
[0046] FIG. 2 is a circuit view of the circuit configuration of a
high voltage generator.
[0047] FIG. 3 is a view showing a process in which ice crystal
nucleuses are formed in a liquid during the cooling.
[0048] FIG. 4 is a view showing a process of preventing the ice
crystal nucleus formation, which is applied to an apparatus for
supercooling according to the present invention.
[0049] FIG. 5 is a schematic configuration view of the apparatus
for supercooling according to the present invention.
[0050] FIG. 6 is a graph showing a supercooled state of water in
the apparatus for supercooling of FIG. 5.
[0051] FIG. 7 is an exploded perspective view of a non-freezing
storage unit according to a first embodiment of the present
invention.
[0052] FIG. 8 is a perspective view of the non-freezing storage
unit according to the first embodiment of the present
invention.
[0053] FIG. 9 is a sectional view of the non-freezing storage unit
according to the first embodiment of the present invention.
[0054] FIG. 10 is a view of a metal plate installed in a drawer of
the non-freezing storage unit according to the first embodiment of
the present invention.
[0055] FIG. 11 is a view showing a state where the metal plate is
installed in the drawer of the non-freezing storage unit according
to the first embodiment of the present invention.
[0056] FIG. 12 is a view showing a process in which the drawer of
the non-freezing storage unit of the present invention is inserted
into an outer casing.
[0057] FIG. 13 is a view showing a state where a contact point
portion and a sensor installation portion of the non-freezing
storage unit of the present invention are in contact with each
other.
[0058] FIG. 14 is an exploded perspective view of a front portion
of the drawer included in the non-freezing storage unit according
to the first embodiment of the present invention.
[0059] FIG. 15 is an exploded perspecrive view of a side casing
provided in the non-freezing storage unit according to the first
embodiment of the present invention.
[0060] FIG. 16 is a graph showing food temperature changes sensed
by sensors, when a box fan is not installed.
[0061] FIG. 17 is a graph showing food temperature changes sensed
by the sensors, when the box fan is installed.
[0062] FIGS. 18 to 20 are views of a non-freezing storage unit of a
refrigerator according to a second embodiment of the present
invention.
[0063] FIG. 21 is a view of a refrigerator including the
non-freezing storage unit according to the first or second
embodiment of the present invention.
[0064] FIG. 22 is a side-sectional view of the refrigerator
including the non-freezing storage unit according to the first or
second embodiment of the present invention.
[0065] FIGS. 23 and 24 are views of a non-freezing storage unit
according to a third embodiment of the present invention and a
refrigerator including the same.
MODE FOR INVENTION
[0066] Hereinafter, the present invention will be described in
detail with reference to the exemplary embodiments and the
accompanying drawings.
[0067] FIG. 3 is a view showing a process in which ice crystal
nucleuses are formed in a liquid during the cooling. As illustrated
in FIG. 3, a container C containing a liquid L (or a received
object) is cooled in a storing unit S with a cooling space
therein.
[0068] For example, it is assumed that a cooling temperature in the
cooling space is lowered from a normal temperature to a temperature
below 0.degree. C. (a phase transition temperature of water) or a
temperature below a phase transition temperature of the liquid L.
While the cooling is carried out, it is intended to maintain a
supercooled state of the water or the liquid L (or the received
object) at a temperature below the maximum ice crystal formation
zone (-1.degree. C. to -7.degree. C.) of the water in which the
formation of ice crystals is maximized, or at a cooling temperature
below the maximum ice crystal formation zone of the liquid L.
[0069] The liquid L is evaporated during the cooling such that
vapor W1 is introduced into a gas Lg (or a space) in the container
C. In a case where the container C is closed, the gas Lg may be
supersaturated due to the evaporated vapor W1.
[0070] When the cooling temperature reaches or exceeds a
temperature of the maximum ice crystal formation zone of the liquid
L, the vapor W1 forms ice crystal nucleuses F1 in the gas Lg or ice
crystal nucleuses F2 on an inner wall of the container C.
Alternatively, the condensation occurs in a contact portion of the
surface Ls of the liquid L and the inner wall of the container C
(almost the same as the cooling temperature in the cooling space)
such that the condensed liquid L may form ice crystal nucleuses F3
which are ice crystals.
[0071] For example, when the ice crystal nucleuses F1 in the gas Lg
are lowered and infiltrated into the liquid L through the surface
Ls of the liquid L, the liquid L is released from the supercooled
state and caused to be frozen. That is, the supercooling of the
liquid L is released.
[0072] Alternatively, as the ice crystal nucleuses F3 are brought
into contact with the surface Ls of the liquid L, the liquid L is
released from the supercooled state and caused to be frozen.
[0073] As described above, according to the process of forming the
ice crystal nucleuses F1 to F3, when the liquid L is stored at a
temperature below its maximum ice crystal formation zone, the
liquid L is released from the supercooled state due to the freezing
of the vapor evaporated from the liquid L and existing on the
surface Ls of the liquid L and the freezing of the vapor on the
inner wall of the container C adjacent to the surface Ls of the
liquid L.
[0074] FIG. 4 is a view showing a process of preventing the ice
crystal nucleus formation, which is applied to an apparatus for
supercooling according to the present invention.
[0075] In FIG. 4, to prevent the freezing of the vapor W1 in the
gas Lg, i.e., to continuously maintain the vapor W1 state, the
energy is applied to at least the gas Lg or the surface Ls of the
liquid L so that the temperature of the gas Lg or the surface Ls of
the liquid L can be higher than a temperature of the maximum ice
crystal formation zone of the liquid L, more preferably, the phase
transition temperature of the liquid L. In addition, to prevent the
freezing although the surface Ls of the liquid L is brought into
contact with the inner wall of the container C, the temperature of
the surface Ls of the liquid L is maintained higher than a
temperature of the maximum ice crystal formation zone of the liquid
L, more preferably, the phase transition temperature of the liquid
L.
[0076] Accordingly, the liquid L in the container C maintains the
supercooled state at a temperature below its phase transition
temperature or a temperature below its maximum ice crystal
formation zone.
[0077] Moreover, when the cooling temperature in the storing unit S
is a considerably low temperature, e.g., -20.degree. C., although
the energy is applied to an upper portion of the container C, the
liquid L which is the received object may not be able to maintain
the supercooled state. There is a need that the energy should be
applied to a lower portion of the container C to some extent. When
the energy applied to the upper portion of the container C is
relatively larger than the energy applied to the lower portion of
the container C, the temperature in the upper portion of the
container C can be maintained higher than the phase transition
temperature or a temperature of the maximum ice crystal formation
zone. Further, the temperature of the liquid L in the supercooled
state can be adjusted by the energy applied to the lower portion of
the container C and the energy applied to the upper portion of the
container C.
[0078] The liquid L has been described as an example with reference
to FIGS. 3 and 4. In the case of a received object containing a
liquid, when the liquid in the received object is continuously
supercooled, the received object can be kept fresh for an extended
period of time. The received object can be maintained in a
supercooled state at a temperature below the phase transition
temperature via the above process. Here, the received object may
include meat, vegetable, fruit and other food as well as the
liquid.
[0079] Furthermore, the energy adopted in the present invention may
be thermal energy, electric or magnetic energy, ultrasonic energy,
light energy, and so on.
[0080] FIG. 5 is a schematic configuration view of the apparatus
for supercooling according to the present invention.
[0081] The apparatus for supercooling of FIG. 5 includes a case Sr
mounted in the storing unit S in which the cooling is performed and
having a receiving space therein, a heating coil H1 mounted on the
inside of a top surface of the case Sr and generating heat, a
temperature sensor C1 sensing a temperature in an upper portion of
the receiving space, a heating coil H2 mounted on the inside of a
bottom surface of the case Sr and generating heat, and a
temperature sensor C2 sensing a temperature in the lower portion of
the receiving space or a temperature of a received object P.
[0082] The apparatus for supercooling is installed in the storing
unit S such that the cooling is performed therein. The temperature
sensors C1 and C2 sense the temperature and the heating coils H1
and H2 are turned on to supply heat from the upper and lower
portions of the receiving space to the receiving space. The heat
supply quantity is adjusted to control the temperature in the upper
portion of the receiving space (or the air on the received object
P) to be higher than a temperature of the maximum ice crystal
formation zone, more preferably, the phase transition
temperature.
[0083] The positions of the heating coils H1 and H2 in FIG. 5 are
appropriately determined to supply the heat (or energy) to the
received object P and the receiving space. The heating coils H1 and
H2 may be inserted into side surfaces of the case Sr.
[0084] FIG. 6 is a graph showing the supercooled state of water in
the apparatus for supercooling of FIG. 5. The graph of FIG. 6 is a
temperature graph when the liquid L is water and the principle of
FIGS. 4 and 5 is applied thereto.
[0085] As illustrated in FIG. 6, line I represents a curve of the
cooling temperature in the cooling space, line II represents a
curve of the temperature of the gas Lg (air) on the surface of the
water in the container C or the case Sr (or the temperature in the
upper portion of the container C or the case Sr), and line III
represents a curve of the temperature in the lower portion of the
container C or the case Sr. A temperature of an outer surface of
the container C or the case Sr is substantially identical to the
temperature of the water in the container C or the case Sr.
[0086] As shown, in a case where the cooling temperature is
maintained at about -19.degree. C. to -20.degree. C. (see line I),
when the temperature of the gas Lg on the surface of the water in
the container C is maintained at about 4.degree. C., to 6.degree.
C. which is higher than a temperature of the maximum ice crystal
formation zone of the water, the temperature of the water in the
container C is maintained at about -11.degree. C. which is lower
than a temperature of the maximum ice crystal formation zone of the
water, but the water is stably maintained in a supercooled state
which is a liquid state for an extended period of time. Here, the
heating coils H1 and H2 supply heat.
[0087] Additionally, in FIG. 6, the energy is applied to the
surface of the water or the gas Lg on the surface of the water
before the temperature of the water reaches a temperature of the
maximum ice crystal formation zone, more preferably, the phase
transition temperature due to the cooling. Thus, the water stably
enters and maintains the supercooled state.
[0088] FIG. 7 is an exploded perspective view of a non-freezing
storage unit according to a first embodiment of the present
invention, FIG. 8 is a perspective view of the non-freezing storage
unit according to the first embodiment of the present invention,
and FIG. 9 is a sectional view of the non-freezing storage unit
according to the first embodiment of the present invention.
[0089] The non-freezing storage unit according to the first
embodiment of the present invention roughly includes an outer
casing 100, a drawer 200 and a side casing 300. The drawer 200 can
be inserted into and pulled out of the outer casing 100. As any
separate electronic device is not attached to the drawer 200, the
drawer 200 can be completely separated and detached from the outer
casing 100. The outer casing 100 includes an insulation material
110 to insulate the non-freezing storage unit from the other region
of a refrigerator in which the non-freezing storage unit is
located. The drawer 200 and the side casing 300 also include
insulation materials 210 and 310, respectively. It is thus possible
to insulate the portions which are not sufficiently insulated by
the insulation material 110 of the outer casing 100. Heaters 140
are installed on the inside of the outer casing 100. A control unit
(not shown) adjusts heating values of the heaters 140 to control a
temperature in the non-freezing storage unit. The heaters 140
include an upper heater 142 and a lower heater 144, and the control
unit (not shown) control the heating values of the upper heater 142
and the lower heater 144, respectively. In addition, a sensor 132
for sensing a temperature in the unit which measures the
temperature in the non-freezing storage unit is installed on the
upper side of the outer casing 100. In order to minimize the
influence on the sensor 132 for sensing the temperature in the unit
exerted by the heat of the heaters 140, the heaters 140 may not be
located adjacent to the sensor 132 for sensing the temperature in
the unit, and a separate insulation member (not shown) may be
further installed between the heaters 140 and the sensor 132 for
sensing the temperature in the unit. Moreover, sensors 134 and 136
sensing a temperature of food are provided on the lower side of the
outer casing 100. The sensors 134 and 136 measure the temperature
of the food located in the drawer 200. Preferably, a plurality of
sensors 134 and 136 are installed at given intervals to reflect the
temperature of the food to the operation of the non-freezing
storage unit, when the food is widely distributed in the drawer
200. In this embodiment, although two sensors 134 and 136 are
installed, three or more sensors may be installed. As the sensors
134 and 136 are not installed in the drawer 200 brought into
contact with the food but in the outer casing 100, a cable for use
in transferring power to the sensors 134 and 136 and receiving
temperature sensing information therefrom can be removed from the
drawer 200. There is an advantage in that the drawer 200 can be
completely pulled out of the outer casing 100. If the drawer 200 is
not completely pulled out of the outer casing 100, it is
inconvenient to put the food into the drawer 200 or take the food
out of the drawer 200 and very difficult to clean the drawer 200.
The sensors 134 and 136 are attached to bottom surfaces of sensor
installation portions 134a and 136a of a thin metal plate attached
to the bottom surface of the outer casing 100, and thus are not
exposed to the outside of the outer casing 100.
[0090] FIG. 10 is a view of a metal plate installed in the drawer
of the non-freezing storage unit according to the first embodiment
of the present invention, and FIG. 11 is a view showing a state
where the metal plate is installed in the drawer of the
non-freezing storage unit according to the first embodiment of the
present invention. As described above, in the non-freezing storage
unit according to the first embodiment of the present invention,
since the drawer 200 can be completely pulled out of the outer
casing 100 and separated therefrom, the sensors 134 and 136 are not
located in the drawer 200 but in the outer casing 200. There is a
disadvantage in that the sensitivity of the sensors 134 and 136
sensing the temperature of the food stored in the drawer 200 may be
reduced. To compensate for this, a metal plate 232 receiving a
temperature change of the food distributed in the drawer 200, and
contact point portions 234 and 236 transferring the temperature
change of the metal plate 232 to the sensors 134 and 136 are
provided in a basket 230 of the drawer 200. The contact point
portions 234 and 236 are downwardly protruded from a bottom surface
of the basket 230. When the drawer 200 is completely inserted into
the outer casing 100, the sensor installation portions 134a and
136a and the contact point portions 234 and 236 are brought into
contact without a gap, to thereby effectively transfer the
temperature of the food to the sensors 134 and 136.
[0091] FIG. 12 is a view showing a process in which the drawer of
the non-freezing storage unit of the present invention is inserted
into the outer casing, and FIG. 13 is a view showing a state where
the contact point portion and the sensor installation portion of
the non-freezing storage unit of the present invention are in
contact with each other. The drawer 200 included in the
non-freezing storage unit according to the first embodiment of the
present invention includes the contact point portions 234 and 236
downwardly protruded from the bottom surface of the basket 230.
When the contact point portions 234 and 236 are in contact with the
sensor installation portions 134a and 136a without a gap, the
sensors 134 and 136 can sense the temperature of the food better.
However, while the drawer 200 is moved in the outer casing 100, if
the contact point portions 234 and 236 continuously cause the
friction in contact with the outer casing 100, problems occur such
as the abrasion of the contact point portions 234 and 236 and the
outer casing 100, the noise caused by the friction, and an
excessive force to push and pull the drawer 200. Accordingly, it is
preferable that the contact point portions 234 and 236 should
maintain a given interval from the bottom surface of the outer
casing 100 when the drawer 200 is moved in the outer casing 100,
and should be brought into contact with the sensor installation
portions 134a and 136a when the drawer 200 is completely inserted
into the outer casing 100. For this purpose, guide portions 120 and
220 (see FIG. 12) guiding the movement position of the drawer 200
in the outer casing 100 are provided in the corresponding positions
of the outer casing 100 and the drawer 200, respectively.
[0092] The guide portions 120 and 220 include rails 122 and 222 and
rollers 124 and 224, respectively. When the drawer 200 is inserted
into the outer casing 100, the rollers 124 and 224 of the outer
casing 100 and the drawer 200 are brought into contact with each
other. Next, the rollers 224 of the drawer 200 roll over the rails
122 of the outer casing 100 and the rails 222 of the drawer 200
roll over the rollers 124 of the outer casing 100 at the same time
such that the drawer 200 is inserted into the outer casing 100. The
rails 122 of the outer casing 100 are inclined to the lower portion
so that the drawer 200 can be downwardly moved at the back of the
outer casing 100. In order to prevent the rollers 224 of the drawer
200 from being separated from the rails 122 of the outer casing 100
due to the inclined portions, preferably, the rear portions of the
rails 122 are blocked in a width to accommodate the rollers 224.
Additionally, to prevent the interference between the drawer 200
and the rollers 124 of the outer casing 100 when the drawer 200 is
downwardly moved at the back of the outer casing 100, stepped
portions are formed at the front of the rails 222 of the drawer 200
to accommodate the rollers 124 of the outer casing 100. Therefore,
referring to the drawings, while the drawer 200 is inserted into
the outer casing 100 and moved therein, the contact point portions
234 and 236 can be moved without any interference and friction,
maintaining a given interval from the bottom surface of the outer
casing 100. Moreover, after the drawer 200 is completely inserted
into the outer casing 100, the drawer 200 is downwardly moved by
the guide portions 120 and 220 and the contact point portions 234
and 236 are completely in contact with the sensor installation
portions 134a and 136a.
[0093] FIG. 14 is an exploded perspective view of a front portion
of the drawer included in the non-freezing storage unit according
to the first embodiment of the present invention. Referring to
FIGS. 7 and 14, the front portion of the drawer 200 includes a
front frame 240 defining the frame of the front portion of the
drawer 200 and connected to the basket 230, a cover 250 covering
the front of the front frame 240, a gasket 260 attached to the back
of the front frame 240 and sealing up between the outer casing 100
and the drawer 200 when the drawer 200 is closed, a hook portion
272 fixing the outer casing 100 and the drawer 200 to be closely
attached to each other when the drawer 200 is closed, an elastic
member 274 applying an elastic force to the hook portion 272, and a
grip portion 276 which can release a locked state of the hook
portion 272. In addition, the insulation material 210 of the drawer
200 mentioned above is filled in the front frame 240.
[0094] When taking the drawer 200 out of the outer casing 100 or
inserting the drawer 200 into the outer casing 100, a user can
insert or take out the drawer 200 by holding the cover 250 portion.
For the user's convenience, a handle 252 is formed at the cover 250
portion. Any shape of handle 252 may be used as far as it helps the
user to easily take the drawer 200 out of the casing 100. However,
for the convenience of the use, the handle 252 is formed in the
shape of a groove on the lower side of the front surface of the
cover 250 so that the user can release the locked state of the hook
portion 272 and pull the drawer 200 out at the same time by
gripping the grip portion 276. If the position of the grip portion
276 is changed, the position of the handle 252 may also be changed
so that the user can grip the grip portion 276 and pull the drawer
200 out at the same time.
[0095] As set forth herein, the non-freezing storage unit should be
certainly insulated from the other region of the refrigerator to
stably maintain the non-frozen state of the food. Here, a portion
in which heat exchange with the other region of the refrigerator or
heat leakage probably occurs is a gap between the drawer 200 and
the outer casing 100 located at the front.
[0096] Accordingly, in order to ensure the insulation of the drawer
200 and the outer casing 100, the gasket 260 is attached to a rear
portion of the front frame 240 brought into contact with a front
portion of the outer casing 100. The gasket 260 is made of an
elastic material such as natural rubber or synthetic rubber and
transformed between the drawer 200 and the outer casing 100 by a
force applied from the drawer 200 and the outer casing 100, thereby
sealing up the gap between the drawer 200 and the outer casing
100.
[0097] As described above, when the drawer 200 is completely
inserted into the outer casing 100, the drawer 200 is downwardly
guided by the guide portions 120 and 220 (see FIG. 11). Since the
guide portions 120 and 220 (see FIG. 11) are inclined at the back,
the drawer 200 receives a force in the rearward and downward
directions due to the self weight. Therefore, when the drawer 200
is completely inserted, the gasket 260 is transformed between the
drawer 200 and the outer casing 100 due to the weight of the drawer
200 to seal up the gap. Moreover, the non-freezing storage unit
according to the first embodiment of the present invention includes
a hooked portion 172 and the hook portion 272 locking the outer
casing 100 and the drawer 200 to enhance the sealing. To manipulate
the hook portion 272, the grip portion 276 is located inside the
handle 252 of the cover 250 and rotatably coupled to the front
frame 240. When the user grips the grip portion 276 and holds the
handle 252 with the grip portion 276, the grip portion 276 is
rotated around coupling portions 276a located at both sides of the
grip portion 276 and coupled to the cover 250 such that an upper
part of the grip portion 276 pushes a lower part of the hook
portion 272. The hook portion 272 is also rotated around coupling
portions 272a coupled to the cover 250 such that an upper part of
the hook portion 272 is lifted from the hooked portion 172 of the
outer casing 100 and the coupling of the hook portion 272 and the
hooked portion 172 is released. Thus, the user can pull the drawer
200 out of the outer casing 100. Here, the elastic member 274 with
both ends fixed by the hook portion 272 and the cover 250 is
provided so that the upper part of the hook portion 272 can be
firmly fixed to the hooked portion 172 of the outer casing 100 in a
normal situation, pressing the same. When the user grips the grip
portion 276, the upper part of the hook portion 272 is lifted and
the elastic member 274 is transformed, and when the user releases
the grip portion 276, the upper part of the hook portion 272 is
downwardly moved due to a restoring force of the elastic member
274. The outer casing 100 and the drawer 200 are fixed by the hook
portion 272 and the hooked portion 172. This ensures the sealing
between the outer casing 100 and the drawer 200. FIG. 15 is an
exploded perspective view of the side casing provided in the
non-freezing storage unit according to the first embodiment of the
present invention.
[0098] The insulation material 310, a control panel (not shown), a
control panel mounting portion 320, an operation panel (not shown)
and an operation panel mounting portion 330 are installed in the
side casing 300. The operation panel (not shown), which includes a
button portion 315a, 315b, 315c and 315d enabling the input of
functions of the non-freezing storage unit and a display portion
316 displaying the selected function, displays the function input
through the button portion 315a, 315b, 315c and 315d on the display
portion 316 and transmits information on the inputted function to
the control panel (not shown). Preferably, a window (hole) is
provided in a corresponding position of the side casing 300 to
expose the button portion 315a, 315b, 315c and 315d and the display
portion 316 of the PCB operation substrate to the outside. The
button portion 315a, 315b, 315c and 315d and the display portion
316 are not located on the drawing 200 but on the side casing 300
such that the drawing 200 is completely detachable from the outer
casing 100. The button portion 315a, 315b, 315c and 315d includes a
button 315a selecting a thin ice function, a button 315b selecting
a freezing function, a button 315c selecting a supercooling
function, and a button 315d turning on and off power of the
non-freezing storage unit. The display portion 316 displays the
power-on/off state of the non-freezing storage unit and the
function currently performed in the non-freezing storage unit. When
the user turns on power of the non-freezing storage unit through
the button 315d and selects the thin ice function through the
button 315a, the control panel (not shown) receives an input signal
from the button 315a and displays that the refrigerating function
has been selected through the display portion 316. In addition, the
control panel (not shown) adjusts the heating values of the heaters
140 installed in the outer casing 100 (see FIG. 8) such that the
temperature in the non-freezing storage unit ranges from about
-5.degree. C. to -8.degree. C. The control panel (not shown)
adjusts the heating values of the heaters 140 through the sensor
132 for sensing the temperature in the unit and the sensors 134 and
136 such that the temperature in the non-freezing storage unit
exists in a desirable temperature range. For example, when the meat
is stored in the non-freezing storage unit using the thin ice mode,
it can be easily cut due to thin ices. Moreover, when the user
selects the freezing function through the button 315b, the control
panel (not shown) turns off all the heaters 140 and stores the food
at the same temperature as that of the other region of the
refrigerator without separate temperature control. Meanwhile, when
the user selects the non-freezing function through the button 315c,
the control panel (not shown) continuously senses the temperature
in the non-freezing storage unit and the temperature of the food
through the sensors 132, 134 and 136 and adjusts the heating values
of the heaters 140 so that the temperature in the non-freezing
storage unit can be maintained at about -2.degree. C. to -4.degree.
C. When the meat or the like is stored at a temperature below
0.degree. C. without being frozen by the non-freezing function, it
is possible to prevent the taste from being reduced by the ice
crystal formation in the meat and the destruction of fibers of the
meat.
[0099] In addition, while the meat is stored in the non-freezing
storage unit by the non-freezing function, its non-frozen state may
be broken due to a shock or partial temperature unbalance. Even if
ice crystals are formed in some part, the freezing may be easily
spread to the entire meat. Once the freezing is started, the
temperature is suddenly raised to near 0.degree. C. which is the
phase transition temperature. Therefore, when a sudden temperature
change is sensed by the sensors 134 and 136, it is determined that
the stored food such as the meat, etc. has been frozen. The food in
the non-freezing storage unit is thawed, and then stored again in
the non-frozen state. To thaw the food in the non-freezing storage
unit, preferably, the temperature is raised to near normal
temperature, at least 2.degree. C. and maintained for a given time
such that the food is sufficiently thawed and stored again in the
non-frozen state. Moreover, when the user selects the non-freezing
function, the control panel (not shown) may adjust the heating
values of the heaters 140 via a given algorithm using the sensor
132 for sensing the temperature in the unit and the sensors 134 and
136 so that the temperature in the unit can be maintained at
-2.degree. C. to -4.degree. C. However, the control panel (not
shown) may adjust the heating value of the upper heater 142 merely
using the temperature sensed by the sensor 132 for sensing the
temperature in the unit such that the temperature in the upper
portion of the non-freezing storage unit is maintained at about
-2.degree. C., and may adjust the heating value of the lower heater
144 merely using the temperature sensed by the sensors 134 and 136
such that the temperature in the lower portion of the non-freezing
storage unit is maintained at about -3.degree. C. to -4.degree.
C.
[0100] Meanwhile, a box fan (not shown) may be installed in one
side of the inner space of the outer casing 100 (e.g., the rear
portion of the outer casing) where there is no interference between
the outer casing 100 and the drawer 200 or the inner space of the
side casing 300 so as to produce the forcible flow in the
non-freezing storage unit. If the box fan (not shown) is provided
in the inner space of the side casing 300, a flow vent (not shown)
should be further formed between the side casing 300 and the outer
casing 100 so that the forcible flow caused by the box fan can be
produced in the outer casing 100 in which the basket 230 is
located. In a case where the box fan (not shown) is installed to
produce the forcible flow, the temperature distribution in the
non-freezing storage unit becomes uniform, and thus the sensitivity
of the sensors 134 and 136 sensing the release of the non-frozen
state is improved. FIG. 16 is a graph showing food temperature
changes sensed by the sensors, when the box fan is not installed,
and FIG. 17 is a graph showing food temperature changes sensed by
the sensors, when the box fan is installed. Comparing the two
graphs, when the box fan is not installed, the temperature measured
by the sensors 134 and 136 is fluctuated in a small fluctuation
range, but when the box fan is installed, the entire section is
clearly divided into a section where the temperature fluctuation
range is very small and a section where the temperature fluctuation
range is very large. Accordingly, when the box fan (not shown) is
installed, although the same sensors 134 and 136 are used, it is
possible to control the heating values of the heaters 140 to
maintain the supercooled state with high reliability, and to easily
determine the release of the supercooling (i.e., the start of the
freezing).
[0101] Further, each of the heaters 140, i.e., the upper heater 142
and the lower heater 144 may include a plurality of heaters. When
the non-freezing storage unit performs the non-freezing function,
the plurality of upper heaters 142 and lower heaters 144 are
operated in a state where at least one heater is always on and the
other heaters are on/off according to the temperature measured by
the sensor 132 for sensing the temperature in the unit and the
sensors 134 and 136. When the upper heater 142 and the lower heater
144 are composed of the plurality of heaters, respectively, the
temperature fluctuation range in the unit influenced by the heating
value of the heater is small compared with the on/off of a single
heater. Thus, it is easy to distinguish the temperature fluctuation
caused by the on/off of the heater from the temperature fluctuation
caused by the release of the supercooling. Compared with a large
temperature fluctuation range, a small temperature fluctuation
range can improve the supercooling stability and the freshness of
the food.
[0102] FIGS. 18 to 20 are views of a non-freezing storage unit of a
refrigerator according to a second embodiment of the present
invention. The non-freezing storage unit 100 according to the
second embodiment, which is formed in the shape of a drawer,
includes an outer casing 110 formed in the shape of a
rectangular-parallelepiped and having one open surface (front
surface), and a drawer 120 which can be pulled out and detached
from the outer casing 110 through the open surface (the front
surface in FIGS. 18 to 20) of the outer casing 110. The outer
casing 110 is filled with an insulation material 113 to insulate
the non-freezing storage unit 100 from a cooling space of the
refrigerator such as a refrigerating chamber and a freezing
chamber. The non-freezing storage unit 100 may be used at the same
temperature as that of the refrigerating chamber and the freezing
chamber, but is normally used at a specific temperature different
from the operation conditions of the refrigerating chamber and the
freezing chamber. When the temperature transfer does not occur
between the non-freezing storage unit 100 and the refrigerating
chamber or the freezing chamber, a loss caused by heat exchange can
be minimized.
[0103] A thermoelectric element 111 is installed on the inside of
the outer casing 110. According to the direction of the current
applied to the thermoelectric element 111, the temperature is
lowered at one side for cooling and raised at the other side for
heating. In the non-freezing storage unit 100 of the present
invention, the temperature in the non-freezing storage unit 100 is
adjusted using the thermoelectric element 111, instead of using the
general hotwire heater and the cool air of the refrigerating
chamber or the freezing chamber. When it is intended to lower the
temperature in the non-freezing storage unit 100, the direction of
the current of the thermoelectric element 111 is adjusted to
transfer the temperature change on the cooling side into the
non-freezing storage unit 100, and when it is intended to raise the
temperature in the non-freezing storage unit 100, the direction of
the current of the thermoelectric element 111 is adjusted to
transfer the temperature change on the heating side into the
non-freezing storage unit 100. As the temperature in the
non-freezing storage unit 100 is adjusted through the
thermoelectric element 111, although the non-freezing storage unit
100 is installed in the refrigerating chamber, the temperature in
the non-freezing storage unit 100 can be controlled to be lower
than that of the refrigerating chamber. The non-freezing storage
unit 100 further includes a conductor 112 which is in contact with
the thermoelectric element 111 so that the temperature change of
the thermoelectric element 111 can be evenly transferred into the
non-freezing storage unit 100. Preferably, the conductor 112 is
formed to cover the entire inner surface of the outer casing
110.
[0104] The relative installation positions of the outer casing 110,
the thermoelectric element 111 and the conductor 112 will be
described. The thermoelectric element 111 may be installed on the
inner surface of the outer casing 110, and then the conductor 112
may be installed to cover the thermoelectric element 111. The
temperature change on one side of the thermoelectric element 111
which is in contact with the conductor 112 is conducted through the
conductor 112 and evenly transferred into the non-freezing storage
unit 100, and the temperature change on the other side of the
thermoelectric element 111 is insulated by the insulation material
113 of the outer casing 110 and prevented from being transferred
into the refrigerating chamber or the freezing chamber in which the
non-freezing storage unit 100 is located. One or plural
thermoelectric elements 111 may be installed on the upper side of
the inner surface of the outer casing 110, and one or plural
thermoelectric elements 111 may be installed on the upper side and
the lower side thereof, respectively. The thermoelectric element
111 is connected to a control unit (not shown), and the control
unit (not shown) controls the direction and amplitude of the
current flowing through the thermoelectric element 111 to maintain
a set temperature input by a user or a temperature preset in the
control unit (not shown).
[0105] For another example, the conductor 112 may be installed on
the inner surface of the outer casing 110, and then the
thermoelectric element 111 may be installed in contact with the
conductor 112. Here, one side of the thermoelectric element 111 is
in contact with the conductor 112 and the other side thereof is
exposed in the non-freezing storage unit 100. As illustrated in
FIG. 19, the area of one side of the thermoelectric element 111
exposed in the non-freezing storage unit 100 is larger than the
area of the conductor 112 exposed in the non-freezing storage unit
100. Since the transfer of the temperature change is performed
between the thermoelectric element 111 and the conductor 112 via
conduction, it is performed at a very high speed. It is thus
recognized that the temperature is almost the same in one side of
the thermoelectric element 111 and the conductor 112. Since the
area of the conductor 112 exposed in the non-freezing storage unit
100 is larger than the area of the thermoelectric element 111
exposed therein, the temperature in the non-freezing storage unit
100 is more influenced by the temperature change of the conductor
112, i.e., the temperature of one side of the thermoelectric
element 111 which is in contact with the conductor 112 than the
other side thereof exposed in the non-freezing storage unit 100.
For example, when the non-freezing storage unit 100 is cooled, the
direction of the current applied to the thermoelectric element 111
is adjusted so that one side of the thermoelectric element 111
which is in contact with the conductor 112 can be operated as the
cooling side and the other side thereof exposed in the non-freezing
storage unit 100 can be operated as the heating side. When the
non-freezing storage unit 100 is used as a heating room, the
direction of the current applied to the thermoelectric element 111
is adjusted in the opposite way. As the other side of the
thermoelectric element 111 causing the temperature change in the
opposite direction to the target direction of the temperature
change of the non-freezing storage unit 100 is exposed, there is an
advantage in that the temperature change slowly occurs in the
non-freezing storage unit 100. When the other side of the
thermoelectric element 111 is exposed in the non-freezing storage
unit 100, if the non-freezing storage unit 100 is used to perform
the general cooling and heating functions, since the cooling and
heating switching time is long, a slight loss may be generated in
terms of the energy efficiency. However, when the non-freezing
storage unit 100 performs the non-freezing function of storing food
at a temperature below 0.degree. C. without freezing the food,
since the temperature change slowly occurs, the stability in a
given temperature region is excellent. This is a very good
operation condition for forming the non-frozen state.
[0106] To perform the non-freezing function, the non-freezing
storage unit 100 needs a sensor 114 which can measure the
temperature inside the non-freezing storage unit 100 or the
temperature of the stored food. Referring to FIGS. 18 and 19, the
sensor 114 is installed on the lower side of the inner surface of
the outer casing 110 to measure the temperature of the food.
Although the sensor 114 is installed on the lower side of the inner
surface of the outer casing 110 adjacent to the position of the
food, it cannot accurately sense the temperature of the food.
Therefore, it is preferable to provide a medium 124 transferring
the temperature of the food to the sensor 114. The medium 124 is
downwardly protruded from a bottom surface of the drawer 120 and
brought into contact with the sensor 114. Meanwhile, to effectively
transfer the temperature of the food located in the drawer 120 to
the sensor 114, a conductor (not shown) is installed on the bottom
surface of the drawer 120 which is in contact with the food.
Preferably, the medium 124 is brought into contact with the
conductor (not shown) and the sensor 114 to transfer the
temperature (temperature change) from the conductor (not shown) to
the sensor 114. In addition, preferably, the periphery of the
sensor 114 is insulated by a sensor insulation material 115 such
that the temperature sensing of the sensor 114 is less affected by
the conductor 112. The sensor 114 receives power through a cable
114a and transfers the sensed temperature information to the
control unit (not shown). The control unit (not shown) controls the
direction and intensity of the current applied to the
thermoelectric element 111 according to the temperature information
sensed by the sensor 114. With respect to the control unit (not
shown), a separate control unit (not shown) irrelevant to a
refrigerator main body may be provided in the outer casing 110 or
the refrigerator main body to control the functions of the
non-freezing storage unit 100, or a control unit (not shown) of the
refrigerator main body may serve to control the functions of the
non-freezing storage unit 100.
[0107] In the meantime, to control the functions of the
non-freezing storage unit 100, operation portions 115a, 115b, 115c
and 115d enabling the input of the functions and a display portion
116 displaying the working state of the non-freezing storage unit
100 are provided at the front of the non-freezing storage unit 100.
Preferably, the operation portions 115a, 115b, 115c and 115d and
the display portion 116 are not installed on the drawer 120 but on
one side of the front of the outer casing 110 so that the drawer
120 can be completely detached from the outer casing 110. If a
module is provided to wirelessly transmit and receive power and
information between the outer casing 110 and the drawer 120, the
operation portions 115a, 115b, 115c and 115d and the display
portion 116 may be installed on the drawer 120, which increases the
manufacturing costs.
[0108] The operation portions 115a, 115b, 115c and 115d include an
operation portion 115a selecting a refrigerating function, an
operation portion 115b selecting a heating function, an operation
portion 115c selecting a supercooling function, and an operation
portion 115d turning on and off power of the non-freezing storage
unit 100. The display portion 116 displays the power-on/off state
of the non-freezing storage unit 100 and the function currently
performed in the non-freezing storage unit 100. When the user turns
on power of the non-freezing storage unit 100 through the operation
portion 115d and selects the refrigerating function through the
operation portion 115a, the control unit (not shown) receives an
input signal from the operation portion 115a and displays that the
refrigerating function has been selected through the display
portion 116. In addition, the control unit (not shown) selects the
direction of the current flowing to the thermoelectric element 111
through the cable 111a so that the side of the thermoelectric
element 111 which is in contact with the conductor 112 can be the
cooling side. When the user selects the heating function through
the operation portion 115b, the control unit (not shown) selects
the direction of the current flowing to the thermoelectric element
111 so that the side of the thermoelectric element 111 which is in
contact with the conductor 112 can be the heating side. Moreover,
when the user selects the non-freezing function through the
operation portion 115c, the control unit (not shown) selects the
direction and amplitude of the current flowing to the
thermoelectric element 111 so that the temperature in the
non-freezing storage unit 100 can be maintained at about -2.degree.
C. to -4.degree. C. For this purpose, the control unit (not shown)
continuously senses the temperature of the food measured by the
sensor 114 and appropriately controls the direction and amplitude
of the current according to the sensed food temperature such that
the temperature in the non-freezing storage unit 100 is maintained
at about -2.degree. C. to -4.degree. C. When the meat or the like
is stored at a temperature below 0.degree. C. without being frozen
by the non-freezing function, it is possible to prevent the taste
from being reduced by the ice crystal formation in the meat and the
destruction of fibers of the meat.
[0109] In the meantime, while the meat is stored in the
non-freezing storage unit 100 by the non-freezing function, its
non-frozen state may be broken due to a shock or partial
temperature unbalance. Even if ice crystals are formed in some
part, the freezing may be easily spread to the entire meat. Once
the freezing is started, the temperature is suddenly raised to near
0.degree. C. which is the phase transition temperature. Therefore,
when a sudden temperature change is sensed by the sensor 114, it is
determined that the stored food such as the meat, etc. has been
frozen. The food in the non-freezing storage unit 100 is thawed,
and then stored again in the non-frozen state. To thaw the food in
the non-freezing storage unit 100, preferably, the temperature is
raised to near normal temperature, at least 2.degree. C. and
maintained for a given time such that the food is sufficiently
thawed and stored again in the non-frozen state.
[0110] FIG. 21 is a view showing an example in which the
non-freezing storage unit according to the first or second
embodiment of the present invention is applied to the conventional
refrigerator. The refrigerator 1000 is divided into a freezing
chamber 1100 and a refrigerating chamber 1200. The non-freezing
storage unit 2000 is installed in the freezing chamber 1100. When
the non-freezing storage unit 2000 is installed in the freezing
chamber 1100, the cool air cooling the freezing chamber 1100 cools
the periphery of the non-freezing storage unit 2000, and thus the
meat in the non-freezing storage unit 2000 is stored at a low
temperature. Generally, the temperature in the freezing chamber
1100 ranges from -8.degree. C. to -18.degree. C., which is lower
than a temperature for storing the meat in a non-frozen state.
However, the control panel (not shown) adjusts the heating values
of the heaters 140 (see FIG. 9) via a given algorithm using the
sensor 132 for sensing the temperature and the sensors 134 and 136
so that the temperature in the non-freezing storage unit 2000 can
be maintained at -2.degree. C. to -4.degree. C., thereby keeping
the meat in the non-frozen state. The user may store the meat in a
frozen state at the same temperature as that of the freezing
chamber 1100 without turning on the heaters 140 (see FIG. 9) or the
thermoelectric element 11 (see FIG. 18). FIG. 22 is a
side-sectional view showing a state where the non-freezing storage
unit according to the first or second embodiment of the present
invention is applied to the conventional refrigerator. The freezing
chamber 1100 and the refrigerating chamber 1200 are arranged on the
left and right sides in the longitudinal direction in the
refrigerator 1000, and the non-freezing storage unit 2000 may be
installed between shelves of the freezing chamber 1100, or the
topmost shelf or the bottommost shelf of the freezing chamber 1100.
An evaporator 1300 is located on a rear surface of the freezing
chamber 1100 to exchange heat with the ambient air to produce the
cool air. The cool air is introduced into the freezing chamber 1100
to maintain the refrigerator 1000 at a low temperature. The cool
air heat-exchanged by the evaporator 1300 is introduced into the
freezing chamber 1100 through a cool air vent 2420 via a duct 1600.
When the freezing chamber 1100 is cooled by the cool air, as far as
the heaters 140 (see FIG. 9) are not operated, the temperature in
the non-freezing storage unit 2000 located in the freezing chamber
1100 is maintained to be the same as that of the freezing chamber
1100. When the heaters 140 are operated by the control of the
control panel (not shown), the temperature in the non-freezing
storage unit 2000 is maintained at -2.degree. C. to -4.degree. C.
to store the meat in the non-frozen state. The non-freezing storage
unit 2000 may be fixed to the freezing chamber 1100 such that only
the drawer can be opened and closed in the forward direction, or
the non-freezing storage unit 2000 itself may be separated from the
freezing chamber 1100. When the non-freezing storage unit 2000 is
manufactured to be separable from the freezing chamber 1100,
preferably, terminals transmitting and receiving electricity are
formed in the freezing chamber 1100 and the non-freezing storage
unit 2000, respectively.
[0111] FIGS. 23 and 24 are views of a non-freezing storage unit
according to a third embodiment of the present invention and a
refrigerator including the same. The non-freezing storage unit
according to the third embodiment of the present invention is
installed in the refrigerator in the form of a so-called home bar.
The refrigerator 1000 includes a refrigerating chamber 1300 storing
food at a temperature range of about 2.degree. C. to 10.degree. C.
and a freezing chamber 1400 storing food at a temperature of about
-18.degree. C., which are separated by a bulkhead. In addition, the
refrigerator 1000 includes a refrigerating chamber door 1100
opening and closing the refrigerating chamber 1300, and a freezing
chamber door 1200 opening and closing the freezing chamber 1400.
The non-freezing storage unit 100 according to the third embodiment
of the present invention is formed in the refrigerating chamber
door 1100 or the freezing chamber door 1200. FIGS. 23 and 24
illustrate an example in which the non-freezing storage unit 100 is
formed in the refrigerating chamber door 1100. A non-freezing
storage unit door 130 is provided on the non-freezing storage unit
100 so that the non-freezing storage unit 100 can be opened and
closed on the outside of the refrigerator 1000, when the
refrigerating chamber door 1100 is closed. A casing 110 defining
the non-freezing storage unit 100 may be separately formed and
installed in the refrigerating chamber door 1100, or may be
integrally formed with the refrigerating chamber door 1100. In FIG.
23, the non-freezing storage unit 100 is integrally formed with the
refrigerating chamber door 1100. Hereinafter, for convenience's
sake, the portion bent to define the non-freezing storage unit 100
is referred to as the casing 110. An insulation material 113 is
filled in the casing 110 to insulate the non-freezing storage unit
100 from the refrigerating chamber 1300. Like the second embodiment
of the present invention, a thermoelectric element 111 is installed
on the inside of the casing 110. The thermoelectric element 111 may
be formed in any one of the upper, lower and side portions of the
casing 110. One or plural thermoelectric elements 111 may be
provided. Moreover, a conductor 112 is installed in contact with
the thermoelectric element 111 to effectively transfer a
temperature change occurring in the thermoelectric element 111 into
the non-freezing storage unit 100. With respect to the installation
relation of the thermoelectric element 111, the conductor 112 and
the casing 110, like the second embodiment, the thermoelectric
element 111 may be installed in the casing 110 and the conductor
112 may be installed to cover the thermoelectric element 111, or
the conductor 112 may be installed in the casing 110 and the
thermoelectric element 111 may be installed on the conductor 112.
Further, a display portion (not shown) and an operation portion
(not shown) may be formed on any one of the upper, lower, left and
right sides of the non-freezing storage unit 100, or may be formed
on the non-freezing storage unit door 130. When the display portion
(not shown) and the operation portion (not shown) are formed on the
non-freezing storage unit door 130, preferably, a cable (not shown)
applying power to the display portion (not shown) and the operation
portion (not shown) and receiving a signal therefrom is guided
through a hinge (not shown) of the non-freezing storage unit door
130.
[0112] Furthermore, preferably, a sensor 117 measuring a
temperature in the non-freezing storage unit 100 and/or a sensor
114 measuring a temperature of food stored in the non-freezing
storage unit 100 are installed in the non-freezing storage unit
100. The sensor 114 transfers the sensed temperature information to
a control unit (not shown), and the control unit (not shown)
controls the direction and intensity of the current applied to the
thermoelectric element 111 according to the temperature information
sensed by the sensor 114. With respect to the control unit (not
shown), a separate control unit (not shown) irrelevant to a
refrigerator main body may be provided in the casing 110 or the
refrigerator main body to control the functions of the non-freezing
storage unit 100, or a control unit (not shown) of the refrigerator
main body may serve to control the functions of the non-freezing
storage unit 100. The control unit (not shown) can control the
functions of the non-freezing storage unit 100 using the same
method as that of the first or second embodiment.
* * * * *