Refrigerator and method for controlling the same

A refrigerator which includes a refrigerating compartment and a freezing compartment, a first evaporator and a second evaporator corresponding to the refrigerating compartment and the freezing compartment, respectively, a compressor compressing refrigerant to be supplied to the first and second evaporators, a first fan and a second fan supplying cool air to the compartments, respectively, an external temperature sensor detecting an external temperature of the refrigerator, a multi-directional valve supplying the refrigerant to at least one of the evaporators, and a control unit operating the compressor and the multi-directional valve, and driving the first fan and the second fan until temperatures of the compartments reach a predetermined reference temperature. When the detected external temperature meets a low temperature condition, the control unit controls the multi-directional valve to supply the refrigerant to the first evaporator such that the compressor is operated and an operation of the first fan is halted.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2005-0090694, filed on Sep. 28, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigerator and a method for controlling the same. More particularly, a refrigerator having improved refrigerating cycle for preventing a dew condensation from occurring in a refrigerating compartment of the refrigerator, and a method for controlling the same.

2. Description of the Related Art

In general, a conventional refrigerator includes a main body having a refrigerating compartment and a freezing compartment for storing the goods such as foods, doors for opening and closing opening sections formed on the refrigerating compartment and the freezing compartment and a refrigerating cycle provided in the main body and supplying cool air to the refrigerating compartment and the freezing compartment for cooling the respective compartments.

In recent, in the refrigerating cycle, when two evaporators are provided for supplying independently cool air to the refrigerating compartment and the freezing compartment. For example, Korean Patent Laid Open publication No. 10-2004-0064787 discloses a refrigerator provided with the refrigerating cycle having two evaporators corresponding to the refrigerating compartment and the freezing compartment, respectively.

Further, Korean Patent Laid Open publication No. 10-1999-0034689 discloses a refrigerator which can prevent a dew condensation from occurring on the main body. This conventional refrigerator adopts the on/off cycle changing method for preventing the dew condensation from occurring on a front surface and side surfaces of the main body in a case that an external temperature is high in summer.

However, in this conventional refrigerator, when the external temperature meets the low temperature condition, the refrigeration operation for cooling the refrigerating compartment is relatively reduced so that moisture contained in cool air entered to an inside of the refrigerating compartment is not discharged to the evaporator, thereby forming dew on a wall surface of the refrigerating compartment.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a refrigerator which can prevent a dew condensation from occurring in a refrigerating compartment and a method for controlling the same.

The foregoing and/or other aspects of the present invention can be achieved by providing a refrigerator including a main body having a refrigerating compartment and a freezing compartment, a first evaporator and a second evaporator provided corresponding to the refrigerating compartment and the freezing compartment, respectively, a compressor to compress refrigerant to be supplied to the first and second evaporators, a first fan and a second fan to supply cool air to the refrigerating compartment and the freezing compartment, respectively, an external temperature sensor to detect an external temperature, a multi-directional valve to supply the refrigerant to at least one of the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, and a control unit operating the compressor and the multi-directional valve, and driving the first fan and the second fan until temperatures of the refrigerating compartment and the freezing compartment reached a predetermined reference temperature, wherein, when the detected external temperature meets a low temperature condition, the control unit controls the multi-directional valve to supply refrigerant to the first evaporator for the refrigerating compartment such that the compressor is operated and an operation of the first fan for the refrigerating compartment is halted.

According to an aspect of the present invention, the refrigerator further includes a refrigerant supplying tube to supply the refrigerant from the compressor to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, a first branch refrigerant tube and a second branch refrigerant tube diverged from the refrigerant supplying tube and opened and closed by the multi-directional valve, the first branch refrigerant tube and the second branch refrigerant tube being connected to the first evaporator and the second evaporator, respectively, and a connecting refrigerant tube connecting an outlet of the first branch refrigerant tube to an inlet of the second branch refrigerant tube.

According to an aspect of the present invention, the control unit controls the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube to supply the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, when the external temperature meets the low temperature condition and while the compressor is operated.

According to an aspect of the present invention, the control unit controls the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube, to supply the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment for a predetermined time, and to close the first branch refrigerant tube and open the second branch refrigerant tube, to supply the refrigerant to the second evaporator for the freezing compartment after a lapse of the predetermined time, when the external temperature meets the low temperature condition and while the compressor is operated.

According to an aspect of the present invention, the refrigerator further includes a condenser provided between the compressor and the multi-directional valve, a first capillary tube provided between the first evaporator for the refrigerating compartment and the multi-directional valve, a second capillary tube provided between the second evaporator for the freezing compartment and the multi-directional valve, and a subsidiary capillary tube provided on the connecting refrigerant tube.

According to an aspect of the present invention, the low temperature condition is approximately below 18°.

The foregoing and/or other aspects of the present invention can be achieved by providing a refrigerator including a main body having a refrigerating compartment and a freezing compartment, a first evaporator and a second evaporator provided corresponding to the refrigerating compartment and the freezing compartment, respectively, a compressor to compress refrigerant to be supplied to the first and second evaporators, a first fan and a second fan to supply cool air to the refrigerating compartment and the freezing compartment, respectively, an external temperature sensor to detect an external temperature, a refrigerant supplying tube to supply the refrigerant from the compressor to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, a first branch refrigerant tube and a second branch refrigerant tube diverged from the refrigerant supplying tube, the first branch refrigerant tube and the second branch refrigerant tube being connected to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, respectively, a connecting refrigerant tube to connect an outlet of the first branch refrigerant tube to an inlet of the second branch refrigerant tube so as to connect the first evaporator to the second evaporator in series, and a control unit to operate the compressor and the multi-directional valve, and to drive the first fan for the refrigerating compartment and the second fan for freezing compartment until temperatures of the refrigerating compartment and the freezing compartment reached a predetermined reference temperature, wherein, when the detected external temperature meets a low temperature condition, the control unit controls the multi-directional valve to supply the refrigerant to the first evaporator for the refrigerating compartment such that the compressor is operated and an operation of the first fan for the refrigerating compartment is halted.

According to an aspect of the present invention, the control unit controls the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube, to supply the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment when the external temperature meets the low temperature condition and while the compressor is operated.

According to an aspect of the present invention, the control unit controls the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube, to supply the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment for a predetermined time, and to close the first branch refrigerant tube and open the second branch refrigerant tube, to supply the refrigerant to the second evaporator for the freezing compartment after a lapse of the predetermined time, when the external temperature meets the low temperature condition and while the compressor is operated.

According to an aspect of the present invention, the refrigerator further includes a condenser provided between the compressor and the multi-directional valve, a first capillary tube provided between the first evaporator for the refrigerating compartment and the multi-directional valve, a second capillary tube provided between the second evaporator for the freezing compartment and the multi-directional valve, and a subsidiary capillary tube provided on the connecting refrigerant tube.

The foregoing and/or other aspects of the present invention can be achieved by providing a refrigerator including a main body having a refrigerating compartment and a freezing compartment, a first evaporator and a second evaporator provided corresponding to the refrigerating compartment and the freezing compartment, respectively, a compressor to compress refrigerant to be supplied to the first and second evaporators, a first fan and a second fan to supply cool air to the refrigerating compartment and the freezing compartment, respectively, an external temperature sensor to detect an external temperature, a refrigerant supplying tube to supply the refrigerant from the compressor to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, a first branch refrigerant tube and a second branch refrigerant tube diverged from the refrigerant supplying tube, the first branch refrigerant tube and the second branch refrigerant tube being connected to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, respectively, a connecting refrigerant tube to connect an outlet of the first branch refrigerant tube to an inlet of the second branch refrigerant tube so as to connect the first evaporator to the second evaporator in series, and a control unit to operate the compressor and the multi-directional valve, and to drive the first fan for the refrigerating compartment and the second fan for freezing compartment until temperatures of the refrigerating compartment and the freezing compartment are reached a predetermined reference temperature, wherein, when the detected external temperature meets a low temperature condition, the control unit controls the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube, to supply the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment such that the compressor is operated and an operation of the first fan for the refrigerating compartment is halted.

According to an aspect of the present invention, the refrigerator further includes a condenser provided between the compressor and the multi-directional valve, a first capillary tube provided between the first evaporator for the refrigerating compartment and the multi-directional valve, a second capillary tube provided between the second evaporator for the freezing compartment and the multi-directional valve, and a subsidiary capillary tube provided on the connecting refrigerant tube.

The foregoing and/or other aspects of the present invention can be achieved by providing a refrigerator including a main body having a refrigerating compartment and a freezing compartment, a first evaporator and a second evaporator provided corresponding to the refrigerating compartment and the freezing compartment, respectively, a compressor to compress refrigerant to be supplied to the first and second evaporators, a first fan and a second fan to supply cool air to the refrigerating compartment and the freezing compartment, respectively, an external temperature sensor to detect an external temperature, a refrigerant supplying tube to supply the refrigerant from the compressor to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, a first branch refrigerant tube and a second branch refrigerant tube diverged from the refrigerant supplying tube, the first branch refrigerant tube and the second branch refrigerant tube being connected to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment, respectively, a connecting refrigerant tube to connect an outlet of the first branch refrigerant tube to an inlet of the second branch refrigerant tube so as to connect the first evaporator to the second evaporator in series, and a control unit to operate the compressor and the multi-directional valve, and to drive the first fan for the refrigerating compartment and the second fan for freezing compartment until temperatures of the refrigerating compartment and the freezing compartment reached a predetermined reference temperature, wherein when the detected external temperature meets a low temperature condition such that the compressor is operated and an operation of the first fan for the refrigerating compartment is halted, the control unit controls the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube, to supply the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment for a predetermined time, and to close the first branch refrigerant tube and open the second branch refrigerant tube, to supply the refrigerant to the second evaporator for the freezing compartment after a lapse of the predetermined time.

According to an aspect of the present invention, the refrigerator further includes a condenser provided between the compressor and the multi-directional valve, a first capillary tube provided between the first evaporator for the refrigerating compartment and the multi-directional valve, a second capillary tube provided between the second evaporator for the freezing compartment and the multi-directional valve, and a subsidiary capillary tube provided on the connecting refrigerant tube.

The foregoing and/or other aspects of the present invention can be achieved by providing a method for controlling a refrigerator including a main body having a refrigerating compartment and a freezing compartment, the method including operating the compressor to compress the refrigerant, controlling a multi-directional valve to supply the refrigerant compressed by the compressor to a first evaporator for the refrigerating compartment and a second evaporator for the freezing compartment, and operating a first fan for the refrigerating compartment and a second fan for the freezing compartment until a temperature of the refrigerating compartment and the freezing compartment reaches a predetermined reference temperature, detecting an external temperature of the refrigerator, and supplying the refrigerant to the first evaporator for the refrigerating compartment such that the compressor is operated and an operation of the first fan for the refrigerating compartment is halted, when the detected external temperature meets a low temperature condition.

According to an aspect of the present invention, wherein the method further includes providing a first branch refrigerant tube and a second branch refrigerant tube to supply refrigerant to the first evaporator and the second evaporator, respectively, connecting outlets of the first evaporator for the refrigerating compartment and the first branch refrigerant tube to an inlet of the second branch refrigerant tube so as to connect the first evaporator for the refrigerating compartment to the second evaporator for the freezing compartment in series, and controlling the multi-directional valve to open and close the first and second branch refrigerant tubes.

According to an aspect of the present invention, the method for controlling the refrigerator further includes controlling the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube, and supplying the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment when the external temperature meets the low temperature condition and while the compressor is operated.

According to an aspect of the present invention, the method for controlling the refrigerator further includes controlling the multi-directional valve to open the first branch refrigerant tube and close the second branch refrigerant tube, to supply the refrigerant to the first evaporator for the refrigerating compartment and the second evaporator for the freezing compartment for a predetermined time, and to close the first branch refrigerant tube and open the second branch refrigerant tube, to supply the refrigerant to the second evaporator for the freezing compartment after a lapse of the predetermined time, when the external temperature meets the low temperature condition and while the compressor is operated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

InFIGS. 1-4, a refrigerator according to the present invention comprises a main body (not shown) having a refrigerating compartment5and a freezing compartment6; a pair of doors (not shown) for opening and closing the refrigerating compartment5and the freezing compartment6, respectively, and refrigerating cycle10having a first evaporator31provided corresponding to the refrigerating compartment5and a second evaporator32provided corresponding to for the freezing compartment6.

In this embodiment of the present invention, the refrigerator has the two-door type main body with the refrigerating compartment5and the freezing compartment6disposed at both sides thereof. However, the present invention is not limited hereto, and the arrangement of the refrigerating compartment5and the freezing compartment6may vary, as necessary.

The refrigerating cycle10comprises the first evaporator31for the refrigerating compartment and the second evaporator32for the freezing compartment, a first fan33and a second fan34to supply cool air generated in the first evaporator31and the second evaporator32to the refrigerating compartment5and the freezing compartment6, respectively, a compressor11to compress refrigerant, an external temperature sensor43to detect an external temperature of the refrigerator, and a control unit51to operate the compressor11according to temperatures of the refrigerating department5and the freezing department6, to supply the refrigerant to the first evaporator31and the second evaporator32and to drive the first fan33and the second fan34until temperatures of the refrigerating department5and the freezing department6are reached a predetermined reference temperature.

The refrigerating cycle10comprises a refrigerant supplying tube21to supply the compressed refrigerant to the first evaporator31and the second evaporator32, a first branch refrigerant tube25and a second branch refrigerant tube26diverged from the refrigerant supplying tube21to be connected to the first evaporator31and the second evaporator32, respectively, a connecting refrigerant tube28for connecting an outlet of the first branch refrigerant tube25to an inlet of the second branch refrigerant tube26, and a multi-directional valve23provided among the refrigerant supplying tube21, the first and second branch refrigerant tubes25and26so as to close and open the first and second branch refrigerant tubes25and26.

The refrigerating cycle10comprises a condenser13for condensing the refrigerant compressed in the compressor11and supplying the condensed refrigerant to the refrigerant supplying tube21, and first and second capillary tubes17and18mounted to the first and second branch refrigerant tubes25and26provided at outlet sides of the multi-directional valve23, respectively. The refrigerating cycle10further comprises a hot pipe15connected between the condenser13and the refrigerant supplying tube21to prevent a dew condensation from occurring at a front region of the main body (not shown) where cool air within the refrigerator and hot air outside the refrigerator meet when the door is opened.

The refrigerating cycle10further comprises defrosting heaters41provided adjacent to the first evaporator31and the second evaporator32, respectively, and defrosting temperature sensors42for detecting temperatures of the first evaporator31and the second evaporator32, respectively. The refrigerating cycle10further comprise a refrigerating compartment temperature sensor45for detecting a temperature of the refrigerating compartment5and a freezing compartment temperature sensor46for detecting a temperature of the freezing compartment6.

In an embodiment of the present invention, the external temperature sensor43is mounted to the main body (not shown) for measuring an external temperature outside the refrigerator. However, the present invention is not limited hereto and may vary, as necessary.

The refrigerant supplying tube21is provided between the condenser13and the multi-directional valve23, and thus the refrigerant condensed in the condenser13is supplied to the multi-directional valve23through the refrigerant supplying tube21. The multi-directional valve23can open or close each of the first and second branch refrigerant tubes25and26for supplying the refrigerant supplied from the refrigerant supplying tube21to at least one of the first and second branch refrigerant tubes25and26. In an embodiment of the present invention, a three-way valve is provided as the multi-directional valve23for connecting the refrigerant supplying tube21to the first and second branch refrigerant tubes25and26. However, the present invention is not limited hereto and may vary.

The first capillary tube17and the first evaporator13are mounted to the first branch refrigerant tube25. The first capillary tube17is provided for converting a state of the refrigerant supplied from the multi-directional valve23into a state of a low pressure and a low temperature. The first evaporator31is provided such that the refrigerant passed through the first capillary tube17absorbs ambient heat and is then evaporated.

The second capillary tube18and the second evaporator32are mounted to the second branch refrigerant tube26. The second capillary tube18is provided for converting a state of the refrigerant supplied from the multi-directional valve23into a state of a low temperature and a low pressure. The second evaporator32is provided such that the refrigerant passed through the second capillary tube18absorbs ambient heat and is then evaporated.

The connecting refrigerant tube28connects the outlet of the first branch refrigerant tube25to the inlet of the second branch refrigerant tube26, to supply the refrigerant passed through the first branch refrigerant tube25to the second branch refrigerant tube26. The connecting refrigerant tube28can be connected to the second branch refrigerant tube26between the second capillary tube18and the second evaporator32. A subsidiary capillary tube29can be installed on the connecting refrigerant tube28for converting a state of the refrigerant passed through the first branch refrigerant tube25into a state of lower temperature and a low pressure.

The defrosting heater41removes frost formed on the first evaporator31and the second evaporator32in the state in which an operation of the compressor11is halted. On the basis of the signal regarding the temperature outputted from the defrosting temperature sensors42, the control unit51determines whether to operate the defrosting heater41. When an inside of the refrigerating compartment5is excessively cooled, the defrosting heater41can be operated by the control unit51. Thus, the control unit51controls the first fan33for the refrigerating compartment for enabling air heated by the defrosting heater41to be supplied to the refrigerating compartment5.

In an embodiment of the present invention, once a temperature of one or both of the refrigerating compartment5and the freezing compartment6is reached an upper limit of the preset refrigerating compartment temperature or an upper limit of the preset freezing compartment temperature, the control unit51drives the compressor11, controls the multi-directional valve23to open the first branch refrigerant tube25and operates the first fan33for the refrigerating compartment and the second fan34for the freezing compartment. When a temperature of the refrigerating compartment5is reaches a lower limit of the preset refrigerating compartment temperature which is the reference temperature first, the control unit51halts an operation of the first fan33for the refrigerating compartment and operates continuously the second fan34for the freezing compartment. At this time, since an operation of the first fan33for the refrigerating compartment is halted, in order to enhance an efficiency of the second evaporator32for the freezing compartment, the control unit51controls the multi-directional valve23to open the second branch refrigerant tube26and close the first branch refrigerant tube25. Once temperatures of the refrigerating compartment5and the freezing compartment6both reach a lower limit of the preset refrigerating compartment temperature and a lower limit of the preset freezing compartment temperature which are the reference temperatures, the control unit51halts operations of the compressor11, the first fan33and the second fan34.

The control unit51determines whether the refrigerating compartment5is excessively cooled in a state that an operation of the compressor11is halted and whether to operate the defrosting heater41on the basis of a signal regarding the temperature outputted from the defrosting temperature sensor42. The control unit51receives the signal regarding the temperatures of the refrigerating compartment5and the freezing compartment6outputted from the refrigerating compartment temperature sensor45and the freezing compartment temperature sensor46.

The control unit51compares an external temperature detected by the external temperature sensor43with a preset low temperature condition. When it is determined that the detected external temperature meets the low temperature condition such that the compressor11is operated and the second fan34for the freezing compartment is halted, the control unit51supplies the refrigerant to the first evaporator31so as to form a natural convection by which cool air generated in the first evaporator31and cool air in the refrigerating compartment5are mutually circulated. During the natural convection, the control unit51controls the multi-directional valve23to open the first branch refrigerant tube25and close the second branch refrigerant tube26which supplies the refrigerant to the first evaporator31and the second evaporator32.

As shown inFIG. 3, the control unit51opens the first branch refrigerant tube25for the time ‘A’ from a point of time on which an operation of the first fan33is halted to a point of time on which an operation of the second fan34is halted. Here, although the low temperature condition is approximately below 18° in an embodiment of the present invention, the present invention is not limited hereto. That is, the low temperature condition can be set variously at a temperature approximately below 20° or 12° and the like. When the external temperature meets the low temperature condition, since the temperature of the refrigerating compartment5does not rise considerably, an operation time of the first fan33for the refrigerating compartment becomes short relatively, and thus moisture contained in the cool air supplied to the refrigerating compartment5is not discharged to the first evaporator31and it can cause the dew condensation on a wall surface of the refrigerating compartment5. Due to the above structure, the cool air generated in the first evaporator31for the refrigerating compartment is flown downward and entered to a lower region of the refrigerating compartment5and the cool air existed at an upper region of the refrigerating compartment5is entered to the first evaporator31for the refrigerating compartment, and thus the circulation is generated by the natural convection and it is possible to prevent a dew condensation from occurring on a wall surface of the refrigerating compartment5.

To supply the refrigerant to the first evaporator31and the second evaporator32in a process of natural convection, the control unit51opens the first branch refrigerant tube25and closes the second branch refrigerant tube26for a predetermined time. After a lapse of the predetermined time, the control unit can control the multi-directional valve23such that the first branch refrigerant tube25is closed and the second branch refrigerant tube26is opened to supply the refrigerant to the second evaporator32.

As shown inFIG. 4, the predetermined time ‘B’ for which the natural convection is generated can be less than the time from a point of time on which an operation of the first fan33is halted to a point of time on which an operation of the second fan34is halted, and time ‘B’ can be predetermined variously such as10minutes according to the external temperature and a temperature of the refrigerating compartment5and the like.

To supply the refrigerant to the first evaporator31and the second evaporator32in a process of natural convection, the control unit51controls the multi-directional valve23to open both the first and second branch refrigerant tubes25and26. The control unit51also controls the time to supply the refrigerant to the first evaporator31.

A flow path of the refrigerant in the refrigerating cycle of the refrigerator according to the present invention having the above structure is described as follow.

First, the refrigerant compressed in the compressor11is passed through the condenser13and the hot pipe15and then entered to the refrigerant supplying tube21. The refrigerant entered to the refrigerant supplying tube21can be supplied to at least one of the first branch refrigerant tube25and the second branch refrigerant tube26through the multi-directional valve23.

When the multi-directional valve23opens only the first branch refrigerant tube25according to a control operation of the control unit51, the refrigerant passed through the multi-directional valve23is passed sequentially through the first capillary tube17, the first evaporator31for the refrigerating compartment, the connecting refrigerant tube28, the subsidiary capillary tube29and the second evaporator32for the freezing compartment, and then entered to the compressor11. Thus, the refrigerant passed through the multi-directional valve23is passed successively through the first evaporator31and the second evaporator32.

Also, when the multi-directional valve23opens only the second branch refrigerant tube26according to a control operation of the control unit51, the refrigerant passed through the multi-directional valve23is passed sequentially through the second capillary tube18and the second evaporator32for the freezing compartment, and then entered to the compressor11.

Further, when the multi-directional valve23opens all the first and second branch refrigerant tubes25and26according to a control operation of the control unit51, the refrigerant passed through the multi-directional valve23is supplied to the first and second capillary tubes17and18to enter to the first evaporator31and the second evaporator32. The refrigerant passed through the first evaporator31is supplied to the second evaporator32through the connecting refrigerant tube28and the subsidiary capillary tube18, and then entered to the compressor11.

FIG. 5is a flowchart illustrating a method for controlling a refrigerating cycle of the refrigerator according to an embodiment of the present invention.

InFIG. 5, in operation1, the compressor11is operated according to temperatures of the refrigerating compartment5and the freezing compartment6, the refrigerant compressed by the compressor11is supplied to the first evaporator31and the second evaporator32. Further, the first fan33and the second fan34are operated until the temperatures of the refrigerating compartment5and the freezing compartment6reached the predetermined reference temperature. In an embodiment of the present invention, the first branch refrigerant tube25is opened and the second refrigerant tube26is closed for supplying the refrigerant compressed by the compressor11to the first evaporator31and the second evaporator32. Alternatively, both the first and second branch refrigerant tubes25and26may be opened in order to supply the refrigerant compressed by the compressor11to the first evaporator31and the second evaporator32.

From operation1the process moves to operation3, where an external temperature of the refrigerator is detected by the external temperature sensor43. From operation3, the process moves to operation5, where the control unit determines whether the detected external temperature meets the low temperature condition. When it is determined the external temperature does not meet the low temperature condition in operation5, the process moves to operation7, where the control unit determines whether a temperature of the refrigerating compartment5reaches a lower limit of the preset refrigerating compartment temperature which is the reference temperature. Alternatively, when it is determined that the temperature of the refrigerating compartment5reaches a lower limit of the preset refrigerating compartment temperature in operation7, the process moves to operation9, where the control unit halts an operation of the first fan33for the refrigerating compartment, and closes the first branch refrigerant tube25and opens the second branch refrigerant tube26for increasing a cooling efficiency of the second evaporator32for the freezing compartment. From operation9, the process moves to operation11, where the control unit determines whether the temperature of the freezing compartment6reaches a lower limit of the preset freezing compartment temperature, which is the reference temperature. When it is determined that the temperature of the freezing compartment6reaches a lower limit of the preset freezing compartment temperature in operation11, the process moves to operation13where the operations of the compressor11and the second fan34for the freezing compartment are halted.

Alternatively, when it is determined that the external temperature meets the low temperature condition in operation5, the process moves to operation15, where the control unit decides whether the temperature of the refrigerating compartment5reaches a lower limit of the preset refrigerating compartment temperature, which is the reference temperature. When it is determined that the temperature of the refrigerating compartment5reaches a lower limit of the preset refrigerating compartment temperature in operation15, the process moves to operation17where the control unit halts an operation of the first fan33for the refrigerating compartment, and makes the first branch refrigerant tube25maintain its opened state and the second branch refrigerant tube26maintain its closed state for supplying continuously the refrigerant to the first evaporator31for the refrigerating compartment. Thus, cool air generated in the first evaporator31for the refrigerating compartment and cool air in the refrigerating compartment5are mutually circulated by natural convection, and thus it is possible to prevent a dew condensation from occurring in the refrigerating compartment5.

From operation17, the process moves to operation19, where the control unit determines whether the temperature of the freezing compartment6reaches a lower limit of the preset freezing compartment temperature, which is the reference temperature. When it is determined that the temperature of the freezing compartment6reaches a lower limit of the preset freezing compartment temperature in operation19, the process moves to operation13, where the operations of the compressor11and the second fan34for the freezing compartment are halted.

As described above, in the refrigerator according to an embodiment of the present invention, when the detected external temperature meets the low temperature condition, the refrigerant is supplied to the first evaporator for the refrigerating compartment in the state that the compressor is operated and an operation of the second fan for the freezing compartment is halted, and thus cool air generated in the first evaporator for the refrigerating compartment and cool air in the refrigerating compartment are mutually circulated by natural convection, whereby it is possible to prevent a dew condensation from occurring in the refrigerating compartment.

As described above, according to the present invention, the refrigerator which can prevent a dew condensation from occurring in the refrigerating compartment and a method for controlling the same can be provided.