EP2085724A2

EP2085724A2 - Refrigerator and method of controlling the same

Info

Publication number: EP2085724A2
Application number: EP09152409A
Authority: EP
Inventors: Su Nam Chae; Chang Joon Kim; Sung Jhee; Jun Ho Bae
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2008-01-31
Filing date: 2009-02-09
Publication date: 2009-08-05
Anticipated expiration: 2029-02-09
Also published as: EP2085724B1; ES2610192T3; EP2085724A3; KR20090084047A

Abstract

Provided are a refrigerator and a method of controlling the same. The refrigerator includes a main body (100), a rotatable refrigerator door (12), and a home bar (100). The main body (100) includes a cool air storage compartment. The rotatable refrigerator door is coupled to the main body. The home bar is provided to the refrigerator door and includes at least an opening (101) adapted to access the storage compartment. The home bar also includes a home bar door (103) configured open and close the opening, and a home bar heater (120) on at least one side of the home bar door, the home bar heater including a positive temperature coefficient (PTC) device configured to control, according to a temperature around the home bar (100), an amount of heat generated by the home bar heater (120).

Description

The present disclosure relates to a refrigerator and a method of controlling the refrigerator.
In the related art, a refrigerator includes a plurality of compartments for storing foods or other goods at low temperatures close to or below zero degrees Celsius. Predetermined sides of the storing compartments are opened for allowing access to the foods stored in the storing compartment.
Some of recent refrigerators include a home bar installed in a door for preventing unnecessary leakage of cold air caused by frequent opening and closing of the door. Drinks or foods and the like can be accessed through the home bar without having to open the refrigerator door.
The refrigerator door includes an opening having a predetermined size to access foods through the home bar. The opening may be coupled with a rotatable home bar door to selectively cover the opening.
There is a great temperature difference between the inside and the outside of the refrigerator. That is, a refrigerator compartment inside the refrigerator has a temperature ranging from about 2°C to 3°C, and the outside of the refrigerator has an ambient temperature (about 15 to 25°C) of the room where the refrigerator is installed.
Thus, an insulation material may be inserted into the home bar door to prevent heat transfer caused by the temperature difference between the outside and the inside of the refrigerator.
The home bar may include a home bar heater to prevent the condensation of moisture in air around the home bar caused by a temperature difference between the outside and the inside of the home bar.
Since the home bar door of the refrigerator door has an installing structure where a lower end of the opening has less insulating effect, the lower end of the opening generally has a lower temperature than that of other portions of the opening.
Particularly, to obtain a rotating space of the home bar door, less insulations are inserted into the lower end of the opening than to other portions. Thus, a large amount of cool air inside the refrigerator tends to be emitted through the lower end of the opening to the outside.
However, the related art home bar heater is adjacent to the home bar door along a predetermined portion of the refrigerator door to supply a constant amount of heat. Thus, a low temperature phenomenon occurs especially in the lower end of the opening among peripheral regions of the opening where the home bar door is installed.
Also, moisture in air in the lower end of the opening is condensed on the refrigerator by a temperature difference between the lower end of the opening and the peripheral regions of the refrigerator.
To increase the temperature in the lower end of the opening, the amount of heat provided by the home bar heater is increased. In this case, there is a need for additional power, thereby increasing power consumption costs, and temperatures of other portions of the opening, i.e., an upper end and both side ends are also increased, thereby reducing cooling efficiency inside the refrigerator.
Embodiments of the invention provide a refrigerator configured to improve the structure of a home bar heater provided to a home bar, thereby controlling the amount of heat produced from the heater according to temperature conditions inside and outside the home bar.
Embodiments of the invention also provide a home bar heater optimized to adjust heat produced by the home bar heater using a semiconductor device having various resistances according to temperature, thereby decreasing power consumption for operating the home bar heater.
In one embodiment, a refrigerator includes: a main body including a cool air storage compartment; at least one rotatable refrigerator door coupled to the main body; a home bar provided on the refrigerator door and including at least an opening adapted to provide access inside the storage compartment; a home bar door configured to open and close the opening; and a home bar heater located on at least one side of the home bar door and receiving power from a power supplier (122). This refrigerator is characterized by a positive temperature coefficient (PTC) device connected between the home bar heater and the power supplier and configured to allow a variable amount of power to be supplied to the heater according to a temperature around the home bar; and the home bar heater is adapted to emit a variable amount of heat according to the power supplied.
In another embodiment, a method of controlling a home bar heater of a refrigerator includes: supplying a voltage to a home bar heater through a power supplier when a refrigerator power is applied; providing a positive temperature coefficient (PTC) device (121) between the power supplier and the home bar heater; controlling, by the positive temperate coefficient device, the amount of power supplied to the home bar heater according to a temperature around a home bar; and emitting an amount of heat by the home bar heater according to the supplied power.
According to the above configuration of the present disclosure, in the process where the home bar door is opened and closed, the amount of heat from the heater using the PTC device is controlled according to varied temperature around the home bar, and thus the amount of heat produced by the heater is decreased under a high temperature condition that does not require heat produced by the heater, and the amount of heat produced by the heater is increased under a low temperature condition requiring heat produced by the heater.
Also, the heater produces just a required amount of heat according to the temperature around the home bar, thereby reducing power consumption for the heat produced by the heat.
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, the claims and from the drawings in which:
FIG. 1 is a perspective view illustrating a refrigerator home bar according to an embodiment.
FIG. 2 is a cross-sectional view taken along line I-I' of FIG. 1.
FIG. 3 is a graph illustrating the variation in resistance depending on temperature of a PTC device applied to a home bar heater according to an embodiment.
FIG. 4 is a graph illustrating the variation in current versus voltage, depending on an ambient temperature of a home bar of a refrigerator according to an embodiment.
Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. The present disclosure may, however, be embodied in different forms and should not be constructed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.
FIG. 1 is a perspective view illustrating a refrigerator home bar 100 according to an embodiment.
Referring to FIG. 1, a refrigerator 1 includes a main body 10, a freezer compartment door 11, and a refrigerator compartment door 12. The main body 10 has an open front and includes a freezer compartment (not shown) and a refrigerator compartment (not shown). The freezer compartment door 11 and the refrigerator compartment door 12 are configured to respectively cover portions of the open front of the main body 10.
The refrigerator compartment door 12 includes the home bar 100 in an approximately center thereof to improve storing and accessing of frequently used foods.
A side-by-side-type refrigerator, including a freezer compartment and a refrigerator compartment at left and right sides, will be exemplified in FIG. 1. However, positions of the freezer compartment and the refrigerator compartment are not limited thereto, and a top-mount-type refrigerator in which a freezer compartment and a refrigerator compartment are vertically arranged, or a bottom freezer-type refrigerator in which a refrigerator compartment is disposed on a top side, and the freezer compartment is disposed on a bottom side may be provided according to other embodiments.
Also, the home bar 100 may be provided on the freezer compartment door 11, or to both the refrigerator compartment door 12 and the freezer compartment door 11.
Particularly, the main body 10 includes the refrigerator compartment storing a food required to be at a temperature ranging from about 2 °C to 5 °C, and the freezer compartment storing a food required to be frozen.
More particularly, the home bar 100 includes an opening 101, a home bar frame 102, and a home bar door 103. The opening 101 allows access to a good inside the refrigerator. The home bar frame 102 is disposed on a periphery around the opening 101 to form an appearance of the home bar 100. The home bar door 103 is configured to open and close the opening 101.
Although the opening 101 and the home bar frame 102, which are separately referred in function, are included in the home bar 100, the opening 101 and the home bar frame 102 may be considered as portions of the refrigerator compartment door 12.
An inner surface of the home bar door 103 is provided with a home bar door liner 104. The home bar door liner 104 contacts the home bar frame 102 to close an inner space of the refrigerator 1 in the state where the home bar door 103 covers the opening 101.
The home bar door 103 is rotatably mounted at a lower end of the home bar 100, i.e., a hinge portion 107. The hinge portion 107 may be provided to the refrigerator compartment door 12 on both sides of a lower end of the opening 101.
The home bar door 103 includes a latch member 106 in an inner upper portion thereof. The latch member 106 fixes the home bar door 103 covering the opening 101 to the home bar frame 102.
The home bar frame 102 includes a latch assembly 105 that is, when the home bar door 103 is closed, interlocked with the latch member 106.
When the home bar door 103 is closed, the latch member 106 is inserted into the latch assembly 105 and interlocked with the latch assembly 105, to maintain the closing state of the home bar door 103. The home bar door 103 includes a push part (not shown) in a front surface thereof. The push part is configured to perform a push operation for a user to open the home bar door 103. Thus, the latch member 106 with the push part may be one element of an "opening/closing device" for opening/closing the home bar door 103.
The home bar frame 102 includes a gasket 108 in a front surface thereof. The gasket 108, in the state where the home bar door 103 is closed, contacts the inner surface of the home bar door 103 to close the inner space of the refrigerator 1, thereby preventing the leakage of cool air in the refrigerator 1.
The home bar frame 102 includes a home bar heater 120 therein. The home bar heater 120 heats the periphery of the opening 101 to prevent wet air, i.e., moisture in air from being condensed by a temperature difference between the inside and the outside of the refrigerator 1.
Hereinafter, configuration of the home bar heater 120 and a method of controlling the home bar heater 120 will be described with reference to the accompanying drawings.
FIG. 2 is a cross-sectional view taken along line I-I' of FIG. 1.
Referring to FIG. 2, the home bar heater 120 according to the embodiment of FIG. 1 may be disposed inside the home bar frame 102. The home bar frame 102 may include an insulation material inserted into the home bar frame 102 to thermally insulate the inside and the outside of the refrigerator 1 from each other.
The home bar heater 120 may include a positive temperature coefficient (PTC) device 121.
The PTC device 121, also referred to as a positive temperature coefficient thermistor, is formed of a barium titanate-based ceramic material and has a characteristic where resistance quickly increases with increasing temperature.
Recently, such a PTC device has been used as a safe heating element replacing a nichrome wire. Particularly, the PTC device 121 employs the so-called switch principle where when current flows in a short time, current flow is stopped by the increase of resistance, which may be used for demagnetizing a television shadow mask and starting a motor of an air conditioner.
Such PTC devices are formed in a honeycomb structure and directly heat air passing through the honeycomb structure, which may be adapted for hair driers and clothes driers.
Meanwhile, the home bar heater 120 is disposed around the opening 101. A power supplier 122 is disposed on both sides of the home bar heater 120 to supply a refrigerator power to the home bar heater 120.
When a constant voltage (220 V) is supplied to the main body 10, the home bar heater 120 receives a constant voltage to produce heat.
FIG. 3 is a graph illustrating the variation in resistance depending on temperature of the PTC device 121 applied to the home bar heater 120 according to an embodiment.
Referring to FIG. 3, the home bar heater 120 may employ the PTC device 121 having a characteristic where resistance varies according to temperature. The PTC device 121 may include a ceramic semiconductor device.
The PTC device 121 experiences a decrease in electrical resistance at a low temperature, but when the temperature is over a set value (critical temperature) of a specific temperature, the resistance increases hundreds or thousands of times. As such, the reason why the electrical resistance of the PTC device 121 is rapidly changed is because electrons carrying current do not penetrate through a small ceramic crystal at a high temperature.
In the graph of FIG. 3, the PTC device 121 has a value R_25°C at a room temperature of about 25°C, and a minimum resistance R_min at a temperature T_min greater than about 25°C. In a range of temperature greater than the temperature T_min, the resistance increases in proportion to the increase of temperature.
When the temperature of the PTC device 121 arrives at a critical value T_c, the resistance rapidly increases. Accordingly, the amount of current passing through the PTC device 121 rapidly decreases to decrease the amount of heat generated through the PTC device 121.
Although heat-generating performance of the PTC device 121 depends on an applied high-molecular material, the PTC device 121 may generate heat with a temperature ranging from about 110°C to 180°C. The PTC device 121 has the longer life span than nickel and chrome heaters.
FIG. 4 is a graph illustrating the variation in current versus voltage depending on an ambient temperature of a home bar of a refrigerator according to an embodiment.
Referring to FIG. 4, the PTC device 121 has various current values according to temperature, versus a constant input voltage V_in.
In the table of FIG. 4, a curve (a) expresses a flowing state of a current I_a corresponding to variation of the resistance according to a changed temperature T_a of the PTC device 121 when a temperature around the home bar is low.
A curve (b) expresses a flowing state of a current I_b corresponding to variation of the resistance according to a changed temperature T_b of the PTC device 121 when a temperature around the home bar is a room temperature.
A curve (c) expresses a flowing state of a current I_c corresponding to variation of the resistance according to a changed temperature T_c of the PTC device 121 when a temperature around the home bar is a high temperature over the room temperature.
Here, the relationships between the temperatures of the PTC device 121 are expressed by T_c > T_b > T_a, and the relationships between the currents are expressed by I_a > I_b > I_c.
That is, in the case of the curve (a), the PTC device 121 may emit a great amount of heat with high current. Relatively, in the case of the curve (c), the PTC device 121 may emit a less amount of heat with low current.
That is, the PTC device 121 has various resistances according to the variation of temperature, and current varies corresponding to the various resistances. Since power for the generating of heat is in inverse proportion to resistance with respect to the constant voltage V_in, the greatest power is consumed under condition of the curve (a). Relatively, the least power is consumed under condition of the curve (c).
In this case, the power (the amount of heat produced) is expressed as E = V² / R (where, V is voltage, and R is electrical resistance).
When a home bar door is opened, the temperature around the home bar is decreased by discharged cold air, thereby the temperature of the PTC device 121 is decreased to produce a large amount of heat, and then as time elapses, the temperature of the PTC device 121 increases again. Accordingly, the resistance of the PTC device 121 is increased, and thus the current flowing through the PTC device 121 is decreased to reduce the amount of heat produced.
To sum up, when the PTC device 121 arrives at a preset temperature, the current flowing through the PTC device 121 is decreased, so that stable equilibrium may be achieved between power supplied to the PTC device 121 and the amount of heat consumed.
Hereinafter, operation of the PTC device 121 applied to the home bar heater 120 will now be described.
First, during refrigerator operation, when the home bar door 103 is opened, cool air inside the home bar door 103 is discharged to the outside to decrease temperature around the home bar 100 including the home bar frame 102 and to also decrease the temperature of the PTC device 121.
Also, the electrical resistance of the PTC device 121 is decreased, and thus the current flowing through the PTC device 121 is increased. In addition, since the amount of heat produced is inversely proportional to the resistance, the amount of heat produced by the PTC device 121 is increased.
Then, a predetermined time elapses, and the heat produced by the PTC device 121 increases the temperature thereof, and thus the electrical resistance of the PTC device 121 is increased. As a result, when the temperature around the home bar 100 arrives at a desired temperature, the electrical resistance of the PTC device 121 is increased, and thus the amount of heat produced is increased.
Also, when a compressor is turned off in the state where the home bar 100 is closed, the temperature of the refrigerator 1 is increased as time elapses, and thus the temperature around the home bar 100 is also increased.
Then, as the temperature of the PTC device 121 is increased, the electrical resistance of the PTC device 121 is increased, and the current flowing through the PTC device 121 is decreased. Also, since the amount of heat produced is inversely proportional to the resistance, the amount of heat produced by the PTC device 121 is decreased.
Meanwhile, the PTC device 121 may emit heat in response to variation in the temperature around the refrigerator 1.
That is, in the case where the temperature around the refrigerator 1 is high, a surface temperature around the home bar 100 is also increased, and thus the temperature of the PTC device 121 is increased. Then, according to the above process, the amount of heat emitted from the PTC device 121 is decreased.
On the other hand, in the case where the temperature around the refrigerator 1 is low, the surface temperature around the home bar 100 is decreased, and thus the temperature of the PTC device 121 is decreased. Then, the amount of heat emitted from the PTC device 121 is increased.
According to the above operation of the PTC device of the embodiment, an additional switch device and the on/off control of a switch can be omitted. Since the amount of heat produced by the PTC device is variable according to temperature, it is not necessary to use a large-sized heater to emit the great amount of heat.
Therefore, installation costs of the heater are reduced, and power consumption is decreased.
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. More particularly, various 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.

Claims

A refrigerator comprising:
a main body (10) including a cool air storage compartment;

at least one rotatable refrigerator door (11, 12) coupled to the main body;

a home bar (100) provided on the refrigerator door and including at least an opening (101) adapted to access inside the storage compartment;

a home bar door (103) configured to open and close the opening; and

a home bar heater (120) located on at least one side of the home bar door and receiving power from a power supplier (122),
characterized in that
the home bar heater includes a positive temperature coefficient (PTC) device (121) connected between the home bar heater and the power supplier and configured to allow a variable amount of power to be supplied to the heater according to a temperature around the home bar; and
the home bar heater is adapted to emit a variable amount of heat according to the power supplied.
The refrigerator according to claim 1, wherein the home bar further comprises a home bar frame (102) defining the opening, and the home bar heater is disposed inside the home bar frame.
The refrigerator according to any one of claims 1 or 2, wherein the home bar heater is disposed around the opening.
The refrigerator according to claim 3, wherein the refrigerator comprises a power supplier (122) connected to on both sides of the home bar heater and supplying power to the home bar heater.
The refrigerator according to any one of claims 1 to 4, wherein the positive temperature coefficient device is adapted to allow supplying an increased amount of power to the home bar heater when the temperature around the home bar is decreased and to allow supplying a decreased amount of power to the home bar heater when the temperature around the home bar is increased.
A method of controlling a home bar heater of a refrigerator, the method comprising:
supplying a voltage to a home bar heater (120) through a power supplier (122) when a refrigerator power is applied;

providing a positive temperature coefficient (PTC) device (121) between the power supplier and the home bar heater;

controlling, by the positive temperate coefficient device, the amount of power supplied to the home bar heater according to a temperature around a home bar; and

emitting an amount of heat by the home bar heater according to the supplied power.
The method according to claim 6, wherein when a home bar door is opened during the operation of the home bar heater, the amount of power supplied to the home bar heater is increased and the amount of heat emitted by the home bar heater is increased.
The method according to any one of claims 6 and 7, wherein when a compressor is turned off during the operation of the home bar heater the amount of power supplied to the home bar heater is decreased and the amount of heat emitted by the home bar heater is decreased.
The method according to any one of claims 6 to 8, wherein, when a temperature around the refrigerator is increased, the amount of power supplied to the home bar heater is decreased and the amount of heat emitted by the home bar heater is decreased.
The method according to any one of claims 6 to 9, wherein, when a temperature around the refrigerator is decrease, the amount of power supplied to the home bar heater is increased and the amount of heat emitted by the home bar heater is increased.