Refrigerator and method for controlling the same

Abstract

The present invention relates to a refrigerator and a method for controlling a refrigerator, and more particularly to a refrigerator and a method for controlling a refrigerator in which unnecessary operation of a compressor is prevented for saving power consumption of the refrigerator. The refrigerator includes a compressor, a refrigerating chamber evaporator and a freezing chamber evaporator connected to the compressor, a refrigerant valve for guiding refrigerant to the refrigerating chamber evaporator or the freezing chamber evaporator, and a control unit for controlling the refrigerant valve such that the refrigerant valve blocks or introduces the refrigerant to cause an inside pressure of the freezing chamber evaporator to be elevated higher than an inside pressure of the refrigerating chamber evaporator during evaporation at the refrigerating chamber evaporator for the compressor to draw in the refrigerant remained in the freezing chamber evaporator which did not evaporate.

Claims

1. A method for controlling a refrigerator having a compressor, a refrigerant valve connected to the compressor for guiding refrigerant from the compressor, and a refrigerating chamber evaporator and a freezing chamber evaporator provided to branch pipes connected to an outlet side of the refrigerant valve, comprising: (A) a step of turning off the compressor and closing the refrigerant valve for blocking the refrigerant to the freezing chamber evaporator and the refrigerating chamber evaporator; (B) a step of controlling the refrigerant valve for introducing the refrigerant to the freezing chamber evaporator during a turn off state of the compressor; and (C) a step of putting the compressor into operation, and controlling the refrigerant valve for introducing the refrigerant into the refrigerating chamber evaporator and for blocking the refrigerant to the freezing chamber evaporator for maintaining an inside pressure of the freezing chamber evaporator higher than an inside pressure of the refrigerating chamber evaporator, such that the refrigerant from the freezing chamber evaporator is collected, wherein the step (B) includes the steps of: (B-1) determining whether or not a present time is within a predetermined time range from a compressor operation starting time, and (B-2) when the present time is within the predetermined time range, opening the refrigerant valve to introduce the refrigerant, the refrigerant remained at an inlet side of the refrigerant valve due to turning off of the compressor and closure of the refrigerant valve, only to the freezing chamber evaporator.

2. The method as claimed in claim 1, wherein the predetermined time range in which the refrigerant valve is kept opened in the step (B-2) is a time period required for elevating the inside pressure of the freezing chamber evaporator to be higher than the inside pressure of the refrigerating chamber evaporator in the step (C).

3. The method as claimed in claim 2, wherein the predetermined time range is one minute to one minute thirty seconds.

4. The method as claimed in claim 1, further comprising: (D) a step of controlling the refrigerant valve to block the introduction of the refrigerant to the refrigerating chamber evaporator and to open introduction of the refrigerant to the freezing chamber evaporator if stopping introduction of the refrigerant to the refrigerating chamber evaporator is required during operation of the compressor.

5. The method as claimed in claim 1, wherein a time period in which the refrigerant is kept introduced to the refrigerating chamber evaporator in the step (C) is provided longer than a time period in which the refrigerant remained in the freezing chamber evaporator is drawn into the compressor, entirely.

6. A method for controlling a refrigerator having a first storage chamber, a second storage chamber having a temperature kept lower than the first storage chamber, a compressor, a refrigerant valve connected to the compressor, and first and second evaporators provided to branch pipes connected to an outlet side of the refrigerant valve for forming cold air to be supplied to the first and second storage chambers respectively, wherein the refrigerant valve is for guiding the refrigerant to the first and second evaporators, the method comprising: (1) a step of turning off the compressor and closing the refrigerant valve for blocking the refrigerant to the second evaporator and the first evaporator; (2) a step of controlling the refrigerant valve to supply the refrigerant to the second evaporator to elevate an inside pressure of the second evaporator in a state the compressor is turned off; (3) a step of controlling the refrigerant valve to supply the refrigerant to the first evaporator if supply of the refrigerant to the first storage chamber is required with putting the compressor into operation; and (4) a step of controlling the refrigerant valve to block introduction of the refrigerant to the second evaporator for elevating the inside pressure of the second evaporator higher than the inside pressure of the first evaporator in order to recover the refrigerant from the second evaporator during the step (3), wherein the step (2) includes the step of controlling the refrigerant valve to supply the refrigerant, remained at an inlet side of the refrigerant valve due to turning off of the compressor and closure of the refrigerant valve, only to the second evaporator for a predetermined time period before starting of the compressor.

7. The method as claimed in claim 6, wherein the time period in which the refrigerant valve is kept opened in the step (4) is a time period in which the inside pressure of the second evaporator is elevated higher than the inside pressure of the first evaporator formed in the step (3).

8. The method as claimed in claim 6, further comprising: (5) a step of controlling the refrigerant valve to guide introduction of the refrigerant to the second evaporator and to block the introduction of the refrigerant to the first evaporator, if stopping introduction of the refrigerant to the first evaporator is required during operation of the compressor.

9. The method as claimed in claim 6, wherein a time period in which the refrigerant is kept introduced to the first evaporator in the step (3) is provided longer than a time period in which the refrigerant remained in the second evaporator is drawn into the compressor entirely.

10. A refrigerator comprising: a compressor; a refrigerating chamber evaporator and a freezing chamber evaporator; refrigerant valve for guiding refrigerant to the refrigerating chamber evaporator or the freezing chamber evaporator; and a control unit controlling the refrigerant valve and the compressor, wherein the control unit controls: the compressor being turned off and the refrigerant valve to block the refrigerant to the freezing chamber evaporator and the refrigerating chamber evaporator; the refrigerant valve to introduce the refrigerant to the freezing chamber evaporator in a state the compressor is turned off; and the compressor to be turned on and the refrigerant valve to block the refrigerant to the freezing chamber evaporator and to introduce the refrigerant to the refrigerating chamber evaporator to cause an inside pressure of the freezing chamber evaporator to be elevated higher than an inside pressure of the refrigerating chamber evaporator during evaporation at the refrigerating chamber evaporator for the compressor to draw in the refrigerant remained in the freezing chamber evaporator, and wherein the control unit controls the refrigerant valve such that the refrigerant is introduced only to the freezing chamber evaporator at the time the compressor is turned off.

11. The refrigerator as claimed in claim 10, wherein at the time the compressor is started to operate, the refrigerant valve is opened to the refrigerating chamber evaporator and closed to the freezing chamber evaporator, and wherein the refrigerant valve is kept closed to the freezing chamber evaporator until the inside pressure of the freezing chamber evaporator is kept higher than the inside pressure of the refrigerating chamber evaporator for drawing refrigerant remained in the freezing chamber evaporator is drawn to the compressor, entirely.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the principle of the disclosure. In the drawings:

(2) FIG. 1 illustrates a schematic view of a refrigerator in accordance with a preferred embodiment of the present invention.

(3) FIG. 2 illustrates a block diagram for controlling a refrigerator in accordance with a preferred embodiment of the present invention.

(4) FIG. 3 illustrates a schematic view showing a state in which a compressor is turned off and a refrigerant valve is closed in a refrigerator in accordance with a preferred embodiment of the present invention.

(5) FIG. 4 illustrates a schematic view showing a state in which a compressor is turned off and a refrigerant valve is opened in a refrigerator in accordance with a preferred embodiment of the present invention.

(6) FIG. 5 illustrates a schematic view showing a refrigerating chamber evaporator (or a first evaporator) forms cold air in a refrigerator in accordance with a preferred embodiment of the present invention.

(7) FIG. 6 illustrates a schematic view showing a freezing chamber evaporator (or a second evaporator) forms cold air in a refrigerator in accordance with a preferred embodiment of the present invention.

(8) FIG. 7 illustrates a graph showing changes of pressures at an inlet and an outlet of a compressor according to operation of the compressor and a refrigerant valve in a refrigerator in accordance with a preferred embodiment of the present invention.

(9) FIGS. 8 and 9 illustrate a flow chart showing the steps of a method for controlling a refrigerator in accordance with a preferred embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

(10) Reference will now be made in detail to the specific embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

(11) Referring to FIG. 1, the refrigerator in accordance with a preferred embodiment of the present invention includes a compressor 10 for compressing refrigerant, a condenser 20 connected to an outlet side of the compressor 10, a condenser fan 21 for dissipating heat from the condenser 20, a refrigerant valve 30 for blocking a refrigerant flow or shifting a refrigerant flow passage, first and second expansion devices 41 and 42 provided to branch pipes connected to an outlet side of the refrigerant valve 30, a refrigerating chamber evaporator 61, and a freezing chamber evaporator 51 connected to the first and second expansion devices 41 and 42, respectively.

(12) It is preferable that the refrigerant valve 30 is a three-way valve for enabling to be in communication with the freezing chamber evaporator 51 and the refrigerating chamber evaporator 61.

(13) The freezing chamber evaporator 51 is provided in the freezing chamber F and the refrigerating chamber evaporator is provided in the refrigerating chamber R. And, provided to the freezing chamber F and the refrigerating chamber R, there are a freezing chamber cooling air fan 52 and a refrigerating chamber cooling air fan 62 for moving cold air, respectively.

(14) However, it is not necessary to sort the evaporators into the freezing chamber or the refrigerating chamber evaporators clearly, and the sorting of the evaporators can be applied if any one of a plurality of storage chambers has a temperature lower than the other storage chambers.

(15) Moreover, this principle can be applicable to a plurality of refrigerating chambers.

(16) Therefore, if there are a first storage chamber and a second storage chamber having a temperature lower than the first storage chamber, the evaporators can be sorted as a first evaporator for supplying cold air to the first storage chamber and a second evaporator for supplying the cold air to the second storage chamber.

(17) Therefore, the refrigerating chamber evaporator (or the first evaporator) 61 can be replaced with the first evaporator, and the freezing chamber evaporator (or the second evaporator) 51 can be replaced with the second evaporator.

(18) Moreover, the refrigerating chamber R can be a first storage chamber, the freezing chamber F can be a second storage chamber, the refrigerating chamber cooling air fan 62 can be a first cooling air fan, and the freezing chamber cooling air fan 52 can be a second cooling air fan.

(19) It is apparent that the present invention having such elements replaced thus can also be within a scope of the present invention.

(20) Referring to FIG. 2, there is a display unit 70 connected to an output terminal of a control unit 1, for displaying operation states of the compressor 10, the condenser fan 21, the refrigerant valve 30, the refrigerating chamber cooling air fan (or the first cooling air fan) 62, the freezing chamber cooling air fan (or the second cooling air fan) 52, and the refrigerator.

(21) And, there are a power source unit 2 and an input unit 3 having a predetermined input buttons both provided to an input terminal of the control unit 1.

(22) In this instance, the control unit 1 serves to control above elements for forming the cold air in the freezing chamber (or the second storage chamber) (See FIG. 1) and the refrigerating chamber (or the first storage chamber).

(23) And, as described later, at the time an inside pressure of the freezing chamber evaporator (or the second evaporator) 51 is elevated higher than an inside pressure of the refrigerating chamber evaporator (the first evaporator) 61 (See FIG. 1) temporarily, for making the compressor 10 to draw in the remained refrigerant from the freezing chamber evaporator (or the second evaporator) 51, the control unit 1 controls an operation staring time and opening direction and time of the refrigerant valve 30.

(24) FIG. 3 illustrates a schematic view of a state in which one cycle of operation of the compressor 10 is finished and the compressor 10 is turned off.

(25) In this instance, the refrigerant valve 30 is closed not to introduce the refrigerant to the evaporators 51 and 61.

(26) Accordingly, the refrigerant at a relatively high pressure is positioned at a region marked with an A from the compressor 10 to the refrigerant valve 30 through the condenser 20 mostly, and a portion of the refrigerant at a low pressure is positioned at regions except the A region.

(27) FIG. 7 illustrates a graph showing changes of pressures at an inlet and an outlet of the compressor according to turn on/off states of the compressor and open states of the refrigerant valve in the refrigerator in accordance with a preferred embodiment of the present invention.

(28) Referring to FIG. 7, in a state the compressor 10 is turned off and the refrigerant valve 30 is closed both to the freezing chamber evaporator (or the second evaporator) 51 and the refrigerating chamber evaporator (the first evaporator) 61 (Both close) as shown in FIG. 3, an outlet side pressure Pd of the compressor 10 is higher than an inlet side pressure Ps of the compressor 10, significantly (Step I).

(29) The inlet side pressure Ps of the compressor 10 is similar to an inside pressure of the freezing chamber evaporator (or the second evaporator) 51 or the refrigerating chamber evaporator (the first evaporator) 61 both having the refrigerant to be introduced to the inlet side of the compressor 10 contained therein.

(30) This is because the freezing chamber evaporator (or the second evaporator) 51 or the refrigerating chamber evaporator (the first evaporator) 61 is in communication with the inlet side of the compressor 10.

(31) And, this is also because the refrigerant evaporated in the freezing chamber evaporator (or the second evaporator) 51 or the refrigerating chamber evaporator (the first evaporator) 61 is introduced to the inlet side of the compressor 10 without significant change of temperature or pressure in this state.

(32) Therefore, an inside pressure change of the evaporators 51 and 61 will be described with reference to the inlet side pressure Ps of the compressor 10.

(33) In the meantime, referring to FIG. 4, in a state shown in FIG. 3 (the compressor is in a turned off state), the refrigerant valve 30 is operated to introduce the refrigerant to the freezing chamber evaporator (or the second evaporator) 51.

(34) In this instance, it is also made to introduce the refrigerant to the refrigerating chamber evaporator (the first evaporator) 61. However, since what is important is the introduction of the refrigerant to the freezing chamber evaporator (or the second evaporator) 51, the introduction of the refrigerant to the freezing chamber evaporator (or the second evaporator) 51 is required to be a core matter.

(35) This is for elevating the inside pressure of the freezing chamber evaporator (or the second evaporator) 51 higher than the inside pressure of the refrigerating chamber evaporator (the first evaporator) 61. For this, a high pressure refrigerant is forwarded to the freezing chamber evaporator (or the second evaporator) 51 to mix with the refrigerant remained therein.

(36) In this instance, since the refrigerant valve 30 is opened to at least one of the evaporators for introduction of the refrigerant while keeping the compressor 10 to be turned off, an entire refrigerating cycle is made to be in communication, causing the outlet side pressure and the inlet side pressure of the compressor 10 to become the same, substantially (Step II in FIG. 7).

(37) In this instance, in order to introduce the refrigerant both to the freezing chamber evaporator (or the second evaporator) 51 and the refrigerating chamber evaporator (the first evaporator) 61, the refrigerant valve 30 is opened in both evaporator 51 and 61 directions (Refrigerant valve Both open in the step II, See FIG. 7).

(38) However, it is preferable that opening of the refrigerant valve 30 in middle of a closed state is made a predetermined time period before starting of operation of the compressor 10.

(39) If high temperature and high pressure refrigerant relative to the refrigerant remained in the freezing chamber evaporator (or the second evaporator) 51 and the refrigerating chamber evaporator (the first evaporator) 61 is introduced to the evaporators excessively, temperatures and inside pressures of the evaporators 51 and 61 can be elevated, significantly.

(40) Therefore, it is preferable that a time period the refrigerant valve 30 is kept opened from opening of the refrigerant valve 30 to starting of the compressor 10 is matched to a time period required for the inside pressure of the freezing chamber evaporator (or the second evaporator) 51 to be elevated higher than the inside pressure of the refrigerating chamber evaporator (the first evaporator) 61 at the time the compressor in operation.

(41) In detail, it is preferable that the required time period is 1 minute˜1 minute and thirty seconds.

(42) For an example, if the present time is thirty minutes past one o'clock, and the starting time of the compressor 10 is thirty-two minutes past one o'clock, since there are two minutes until starting of the compressor 10, the refrigerant valve 30 is not opened.

(43) However, if the present time is thirty minutes and thirty seconds past one o'clock, or thirty-one minutes past one o'clock, since the time is one minute or one minute and thirty seconds before the starting time of the compressor 10, the refrigerant valve 30 is opened to introduce the refrigerant to the freezing chamber evaporator (or the second evaporator) 51.

(44) This is for introducing the refrigerant from the freezing chamber evaporator (or the second evaporator) 51 of which pressure is higher than the refrigerating chamber evaporator (or the first evaporator) 61 to the compressor entirely in a case the compressor 10 is in operation and evaporation takes place only at the refrigerating chamber evaporator (or the first evaporator) 61 for forming cold air.

(45) According to this, the refrigerant is introduced from the freezing chamber evaporator (or the second evaporator) 51 which does not make any cold air forming action presently to the compressor 10 again and utilized in the refrigeration cycle.

(46) Referring to FIG. 4, if formation of the cold air is required at the refrigerating chamber (or the first storage chamber) R, if the compressor 10 is put into operation, the refrigerant valve 30 is opened for introducing the refrigerant in a refrigerating chamber evaporator (or the first evaporator) direction (Step III in FIG. 7, the refrigerant valve is in a R open state).

(47) Then, the refrigerating chamber cooling air fan (or the first cooling air fan) 62 is come into operation for supplying the cold air to the refrigerating chamber (or the first storage chamber) R.

(48) In this instance, since the refrigerant valve 30 is closed in a freezing chamber evaporator (or the second evaporator) direction, no refrigerant is introduced in the freezing chamber evaporator (or the second evaporator) direction (Step III in FIG. 7, the refrigerant valve is in an F close state).

(49) Formation of the cold air takes place at the refrigerating chamber evaporator (or the first evaporator) 61 owing to evaporation of the refrigerant and heat exchange of the air, but not at the freezing chamber evaporator (or the second evaporator) 51.

(50) Therefore, since the temperature of the refrigerating chamber evaporator (or the first evaporator) 61 is lower than the temperature of the freezing chamber evaporator (or the second evaporator) 51, the inside pressure of the refrigerating chamber evaporator (or the first evaporator) 61 is lower than the inside pressure of the freezing chamber evaporator (or the second evaporator) 51.

(51) This is because the inside pressure of the refrigerating chamber evaporator (or the first evaporator) 61 is dropped by the evaporation even though the inside of the freezing chamber evaporator (or the second evaporator) 51 is influenced by the high pressure refrigerant introduced thereto during the compressor is turned off.

(52) Under this reason, the refrigerant is introduced to the compressor 10 from the freezing chamber evaporator (or the second evaporator) 51 prior to the refrigerating chamber evaporator (or the first evaporator) 61.

(53) If the refrigerant moves from the freezing chamber evaporator (or the second evaporator) 51 to the compressor 10, causing the pressure of the freezing chamber evaporator (or the second evaporator) 51 to drop lower than the pressure of the refrigerating chamber evaporator (or the first evaporator) 61, starting from this time, the refrigerant is drawn into the compressor from an inside of the refrigerating chamber evaporator (or the first evaporator) 61.

(54) Referring to the step III in a graph illustrating the Ps changes in FIG. 7, there are a dashed line marked with F and a solid line marked with R, wherein the F is higher than R.

(55) This indicates that the inside pressure (marked with R) of the refrigerating chamber evaporator (or the first evaporator) under formation of the cold air is lower than the inside pressure of the freezing chamber evaporator (or the second evaporator) (marked with F) not under formation of the cold air.

(56) By forming a pressure difference thus artificially, different from the related art in which additional operation of the compressor is required only for drawing in the refrigerant, by drawing in the refrigerant remained in the freezing chamber evaporator (or the second evaporator) 51 to the compressor 10 without any additional operation of the compressor, shortage of the refrigerant can be prevented.

(57) Since a time period for forming the cold air at the refrigerating chamber evaporator (or the first evaporator) 61 is a ten and a few minutes to a few ten minutes, the drawing in of the refrigerant remained in the freezing chamber evaporator (or the second evaporator) 51 to the compressor 10 can be made within the time period, adequately.

(58) In the meantime, referring to FIG. 6, a requirement for cutting off the refrigerant introduction to the refrigerating chamber evaporator (or the first evaporator) 61 takes place due to formation of an environment, such as the inside temperature of the refrigerating chamber (or the first storage chamber) R reaches to a lower limit, or the like.

(59) And, if introduction of the refrigerant to the freezing chamber evaporator (or the second evaporator) 51 is required for supplying the cold air to the freezing chamber (or the second storage chamber) F, the refrigerant valve 30 blocks a flow passage to the refrigerating chamber evaporator (or the first evaporator) 61 (Step IV in FIG. 7, the refrigerant valve is in a R close state), and opens a flow passage to the freezing chamber evaporator (or the second evaporator) 51 (The refrigerant valve is in an F open state).

(60) And, if a condition something like the inside temperature of the freezing chamber F reaches to a lower limit is met, the compressor 10 is turned off, requiring no more formation of the cold air at the freezing chamber evaporator (or the second evaporator) 51.

(61) Accordingly, the compressor 10 stops operation, and the refrigerant valve 30 blocks the introduction of the refrigerant to the refrigerating chamber evaporator (or the first evaporator) 61 and the freezing chamber evaporator (or the second evaporator) 51 (Step I in FIG. 7, the refrigerant valve 30 is in a Both close state).

(62) Referring to FIG. 7, in the step I, the compressor is in a turned off state, and the refrigerant valve 30 is also in closed states to all of the evaporators. According to this, a difference of inside pressures takes place between the inlet side and the outlet side of the refrigerant valve 30.

(63) In detailed numerical values, the outlet side pressure of the compressor in the step I is about 3.7˜4.0 bar. And, the inlet side pressure of the compressor (substantially the same with the pressure of the evaporators) is about 0.9˜0.95 bar.

(64) Then, if the refrigerant valve 30 is opened in all evaporator directions while the compressor maintains a turned off state in the step II, making all pressures in the cycle the same, the outlet side pressure of the compressor and the inlet side pressure of the compressor (evaporator pressure) becomes in a range of about 1.5˜2.0 bar.

(65) And, in the step III, the compressor is turned on, and the refrigerant valve is opened in a refrigerating chamber evaporator (or the first evaporator) direction (R open), and blocked in a freezing chamber evaporator (or the second evaporator) direction (F close).

(66) Owing to this, even though the inside pressure of the freezing chamber evaporator (or the second evaporator) is maintained the same with 1.5˜2.0 bar in the step II, the inside pressure of the refrigerating chamber evaporator (or the first evaporator) becomes in a range of about 0.95˜1.0 bar as the inside pressure of the refrigerating chamber evaporator (or the first evaporator) is dropped by evaporation for forming the cold air.

(67) Such a pressure difference causes the refrigerant drawn into the compressor from the inside of the freezing chamber evaporator (or the second evaporator) prior to the refrigerant in the refrigerating chamber evaporator (or the first evaporator). In this instance, check valves on pipes connected to the outlets of the evaporators block introduction of the refrigerant from the evaporator which is at higher pressure to the evaporator which is at lower pressure.

(68) In the meantime, after formation of the cold air is finished at the refrigerating chamber, in order to start formation of the cold air at the freezing chamber, an open direction of the refrigerant valve is changed in middle of operation of the compressor like the step IV.

(69) According to this, the refrigerant valve is blocked in the refrigerating chamber evaporator (or the first evaporator) direction (R close) and opened in the freezing chamber evaporator (or the second evaporator) direction (F close). And, the freezing chamber cooling air fan comes into operation, to introduce the cold air into the freezing chamber. And, upon finishing the step IV, the step I state comes again.

(70) Above operation will be summarized by using a flow chart.

(71) Referring to FIG. 8, in a state the compressor is turned off and the refrigerant valve is closed, i.e., in a state introduction of the refrigerant to the refrigerating chamber evaporator (or the first evaporator) and the freezing chamber evaporator (or the second evaporator) are blocked (S801), the present time is compared to a compressor operation starting time, to determine whether the present time is within a predetermined time range or not (S802).

(72) This is for determining a time for introducing the high pressure and high temperature refrigerant remained in an inlet side of the refrigerant valve to the freezing chamber evaporator (or the second evaporator) {and the refrigerating chamber evaporator (or the first evaporator)} during the compressor is turned off.

(73) As a result of the determination, if it is determined that the present time is before a predetermined time range of starting operation of the compressor, the refrigerant valve is opened (S803). Accordingly, the refrigerant is introduced to the freezing chamber evaporator (or the second evaporator) {and the refrigerating chamber evaporator (or the first evaporator)} (S804).

(74) Accordingly, the inside pressure of the freezing chamber evaporator (or the second evaporator) {and the refrigerating chamber evaporator (or the first evaporator)} is elevated.

(75) In this state, it is determined whether the present time is the compressor operation starting time or not (S805), if it is determined that the present time is the compressor operation starting time, the refrigerant valve is operated to block introduction of the refrigerant to the freezing chamber evaporator (or the second evaporator) {That is, the flow passage to the freezing chamber evaporator (or the second evaporator) is blocked} (S806).

(76) Then, a refrigerant introducing state to the refrigerating chamber evaporator (or the first evaporator) is maintained or started {That is, the flow passage to the refrigerating chamber evaporator (or the first evaporator) is opened (S807)}. And, the refrigerating chamber cooling air fan is come into operation for introducing the cold air formed by the refrigerating chamber evaporator (or the first evaporator) to the inside of the refrigerating chamber.

(77) In this state, alike the step III in FIG. 7, since the inside pressure F of the freezing chamber evaporator (or the second evaporator) is higher than the inside pressure R of the refrigerating chamber evaporator (or the first evaporator), the refrigerant can be drawn from the inside of the freezing chamber evaporator (or the second evaporator) to the compressor, causing most of, or entire refrigerant is drawn from the inside of the freezing chamber evaporator (or the second evaporator) to the compressor.

(78) Under this state, it is determined whether formation of the cold air at the refrigerating chamber is required no more or not, and formation of the cold air at the freezing chamber is required or not (S808).

(79) As a result of the determination, if determined required, the refrigerant valve is put into operated again, to block the introduction of the refrigerant to the refrigerating chamber evaporator (or the first evaporator) {That is, the flow passage to the refrigerating chamber evaporator (or the first evaporator) is closed} (S901).

(80) And, the refrigerant valve is opened to the freezing chamber evaporator (or the second evaporator) for introduction of the refrigerant to the freezing chamber evaporator (or the second evaporator). {That is, the flow passage to the freezing chamber evaporator (or the second evaporator) is opened} (S902).

(81) And, the freezing chamber cooling air fan (or the second cooling air fan) is put into operation, for introducing the cold air formed by the freezing chamber evaporator (or the second evaporator) to the inside of the freezing chamber (or the second storage chamber).

(82) After a certain time period is passed after the formation of the cold air takes place for cooling the freezing chamber (or the second storage chamber), whether a compressor turn off condition is met or not is determined owing to completion of a compressor operation time period or meeting a temperature condition of the freezing chamber (or the second storage chamber) or the refrigerating chamber (or the first storage chamber) (S903).

(83) Accordingly, if it is determined that the compressor operation time period is completed, or the inside temperature of the freezing chamber (or the second storage chamber) or the refrigerating chamber (or the first storage chamber) meets a predetermined temperature condition, the compressor is turned off (S904).

(84) Then, the refrigerant valve is closed, preventing the refrigerant from introducing to the freezing chamber evaporator (or the second evaporator) and the refrigerating chamber evaporator (or the first evaporator) (S905).

(85) It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.