JP6611905B2 - refrigerator - Google Patents

Description

  The present invention relates to a refrigerator.

  Some conventional refrigerators include a refrigerant circulation circuit in which a storage chamber, a compressor, a plurality of condensers, a decompression device, and an evaporator are connected by piping. A refrigeration cycle is constructed with the above configuration, and the storage chamber is cooled by driving the compressor.

  In a conventional refrigerator, food is stored in a storage room by cooling air with an evaporator. The temperature in the refrigerator is 2-5 ° C. for refrigeration and -20 ° C. to −15 ° C. for refrigeration, so the evaporator temperature needs to be 0 ° C. or lower. As a result, water vapor in the air in the refrigerator adheres to the evaporator as a condensate, and is then cooled to freeze (frost). When the refrigerator is operated for a long time, frost formation proceeds and frost accumulates on the evaporator surface. As a result, it becomes difficult for air to pass through and the cooling performance decreases. In order to solve this problem, a defrosting operation in which frost attached to the evaporator is melted with a heater or the like is periodically performed.

  Drain water generated by the defrosting operation passes through a pipe provided at the lower part of the evaporator and is discharged into a machine room provided at the lower part of the refrigerator. In the machine room, a compressor, a blower, a drain water tray for receiving drain water, a first condenser immersed in a drain water solution and dissipating heat by the drain water, and the outside air sucked by the blower are radiated by heat. A second condenser is installed (see Patent Document 1).

JP 58-221369 A

  After the defrosting operation, drain water accumulates in the drain water tray. Since drain water is low temperature, the heat dissipation of the first condenser increases. If the number of revolutions per unit time of the blower does not change, the heat dissipation amount of the second condenser also does not change. Therefore, when the two condensers are viewed as a whole, the heat dissipation amount increases by the increase in the heat dissipation amount of the first condenser. When the amount of heat release increases, the condensation temperature decreases, so the power of the compressor can be reduced, thus saving energy.

  However, if the amount of heat release becomes excessive, the liquid refrigerant stagnates on the condenser side. When liquid refrigerant accumulates on the high pressure side, the difference between high pressure and low pressure widens, and there is a problem that performance such as COP (Coefficient of Performance) of the refrigeration cycle deteriorates.

  This invention was made in order to solve the above problems, and provides a refrigerator capable of cooling operation that realizes energy saving without deteriorating the performance of the refrigeration cycle after completion of the defrosting operation. With the goal.

  In the refrigerator of the present invention, during the cooling operation period, the refrigerant is configured to circulate in the order of the compressor, the first condenser, the second condenser, the decompression device, and the evaporator, and the evaporation And a drain pan for storing drain water generated in the vessel. The first condenser is accommodated in the drain pan. The refrigerator further includes a fan for sending air to the second condenser. The cooling operation period includes a first cooling operation period following the evaporator defrosting operation period and a second cooling operation period following the first cooling operation period. The rotational speed of the fan in at least a part of the first cooling operation period is smaller than the rotational speed of the fan in the second cooling operation period.

  According to the present invention, since the number of rotations of the fan is reduced during the first cooling operation period in which there is drain water after the defrosting operation, the heat radiation amount can be adjusted appropriately. As a result, high-performance operation is possible and energy saving can be realized.

3 is a structural diagram of a cross section of the refrigerator according to Embodiment 1. FIG. It is a figure showing the machine room installed in the back lower part of a refrigerator. It is the figure which looked at the whole refrigerator from the back side. 3 is a timing chart illustrating a control procedure according to the first embodiment. 3 is a flowchart illustrating a control procedure according to the first embodiment. FIG. 4 is a structural diagram of a cross section of a refrigerator according to a second embodiment. 6 is a flowchart showing a procedure for obtaining a low rotational speed time of a machine room fan in a second embodiment. It is a flowchart showing the procedure of the process of step S204 of FIG. FIG. 6 is a structural diagram of a cross-sectional view of a refrigerator according to a third embodiment. 10 is a flowchart showing a procedure for obtaining a low rotational speed time of a machine room fan in a third embodiment. FIG. 6 is a structural diagram of a cross-sectional view of a refrigerator according to a fourth embodiment. 10 is a flowchart showing a procedure for obtaining a low rotational speed time of a machine room fan in a fourth embodiment. FIG. 10 is a structural diagram of a cross-sectional view of a refrigerator according to a fifth embodiment. It is a figure showing the relationship between the amount of frost formation and the speed of the temperature rise of the evaporator 4 during a defrost operation. 10 is a flowchart showing a procedure for obtaining a low rotational speed time of a machine room fan in a fifth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
FIG. 1 is a structural diagram of a cross section of the refrigerator 51 of the first embodiment.

As shown in FIG. 1, the refrigerator 51 includes a refrigeration cycle device 81.
The refrigeration cycle apparatus 81 includes a compressor 1, a condenser 2, and a decompressor (capillary ) that are communicated with each other.
3 and the evaporator 4. During the cooling operation, the refrigerant circulates in the order of the compressor 1, the condenser 2, the decompressor 3, and the evaporator 4.

  The evaporator 4 is disposed in the cooling chamber 10. The compressor 1, the condenser 2, and the decompressor 3 are disposed in the machine room 11. Although the machine room 11 may be arranged in addition to these, the description is omitted in FIG. 1 and described in FIG.

The movement of the refrigerant flowing in the refrigeration cycle apparatus 81 will be described.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is a drain water evaporation condenser (water-cooled condenser: first condenser), machine room condenser (air-cooled condenser: second condenser), side face The high-pressure liquid refrigerant is obtained by passing through the condenser 2 composed of pipes in this order and exchanging heat with the outside air. In FIG. 1, the condenser 2 is simplified, and only the air-cooled condenser is shown.

  The condensed high-pressure liquid refrigerant is decompressed by a decompressor 3 configured by a decompression valve, and becomes a low-pressure and low-temperature two-phase refrigerant.

  Thereafter, the refrigerant flows into the evaporator 4 installed in the refrigerator 51. In the evaporator 4, the air in the refrigerator 51 and the refrigerant exchange heat. The air in the refrigerator 51 is cooled by the refrigerant, and the refrigerant becomes a low-pressure gas refrigerant. Thereafter, the refrigerant that has become low-pressure gas flows into the compressor 1 and is pressurized again and discharged.

  Next, the flow of the cooling air in the refrigerator 51 in Embodiment 1 will be described. In FIG. 1, the solid line arrows represent the flow of air cooled in the cooling chamber 10 from the storage chambers 7a, 7b, and 7c. A dotted arrow represents a flow in which the air that has cooled the storage chambers 7a, 7b, and 7c returns to the cooling chamber.

  The air cooled by heat exchange with the refrigerant in the cooling chamber 10 is transported by the refrigerator fan 5a and flows into the storage chambers 7a, 7b, 7c through the air passage connected to the storage chambers 7a, 7b, 7c. Then, the storage chambers 7a, 7b, and 7c are cooled.

  The storage chambers 7a, 7b, and 7c are adjusted by adjusting the air volume of the cooling air by changing the number of rotations (that is, the rotation speed) of the fan 5a for the refrigerator or operating the air volume regulator 6 (damper). Adjust the temperature. The cooling air that has cooled the storage chambers 7a, 7b, and 7c passes through the return air passage, flows into the cooling chamber again, and is cooled again by the evaporator 4.

  The refrigerator 51 further includes a controller 30. The controller 30 controls each component in the refrigerator 51.

Next, the structure arrange | positioned in a machine room is demonstrated.
FIG. 2 is a diagram illustrating the machine room 11 installed at the lower back of the refrigerator 51.

  The machine room 11 is provided with a compressor 1, a drain water evaporating dish (drain pan) 8, a drain water evaporating condenser 2a, a machine room condenser 2b, and a machine room fan 5b.

  The radiant heater 38 is disposed between the evaporator 4 and the drain water evaporation tray 8. The radiant heater 38 includes a heating wire for warming air. The knuckle heater 37 is installed in direct contact with the evaporator 4. During the defrosting operation of the evaporator 4, the radiant heater 38 and the click heater 37 are operated.

  A hole 12 for discharging drain water generated in the evaporator 4 by the defrosting operation is provided in the upper part of the drain water evaporating dish 8. Drain water falls through the hole 12 to the drain water evaporating dish 8 by gravity.

  The drain water evaporation condenser 2a, which is a water-cooled condenser, is accommodated in the drain water evaporation dish 8, and can be cooled by the drain water when there is drain water in the drain water evaporation dish 8.

  When the machine room fan 5b rotates, outside air is taken in from the side surface of the refrigerator 51, and the outside air is sent to the machine room condenser 2b, which is an air-cooled condenser, to cool the machine room condenser 2b. Further, by rotation of the machine room fan 5b, it is possible to send outside air to the compressor 1 and the drain water evaporation condenser 2a to cool them.

FIG. 3 is a view of the entire refrigerator 51 as seen from the back side.
In the sheet metal on the side surface of the refrigerator 51, a side pipe 2c through which high-pressure refrigerant flows is provided. Through this side surface, the refrigerant flowing through the side pipe 2c and the outside air exchange heat. Note that the pipe through which such a high-pressure refrigerant flows is not only installed on the side surface, but may be installed so as to pass through the ceiling of the refrigerator 51. Thereby, the heat radiation area can be increased.

  Next, a method for controlling the number of rotations (rotational speed) per unit time of the machine room fan 5b in the first embodiment will be described. FIG. 4 is a timing chart showing the control procedure of the first embodiment. FIG. 5 is a flowchart showing the control procedure of the first embodiment.

  Referring to FIGS. 4 and 5, when the temperature of evaporator 4 detected by a temperature sensor (not shown) or the like is lower than a predetermined threshold value TH1 in step S101, the process proceeds to step S102. In FIG. 4, it is assumed that the temperature of the evaporator 4 becomes lower than a predetermined threshold value TH1 at time t1. The threshold TH1 is set to a temperature at which a predetermined amount of frost is stacked on the surface of the evaporator 4 and the cooling performance is expected to decrease by a certain amount. This threshold value TH1 can be obtained from experiments or simulations.

  In step S102, the controller 30 stops the cooling operation and starts the defrosting operation. That is, the controller 30 stops the cooling operation by stopping the compressor 1, energizes the knuckle heater 37, radians, and the heater 38 to defrost the evaporator 4. Furthermore, the controller 30 stops the machine room fan 5b.

  In step S103, when the temperature of the evaporator 4 becomes higher than the predetermined threshold value TH2, the process proceeds to step S104. In FIG. 4, it is assumed that the temperature of the evaporator 4 becomes higher than a predetermined threshold value TH2 at time t2. The threshold TH2 is set to a temperature at which defrosting of the evaporator 4 is expected to be completed. This threshold value TH2 can be obtained from experiments or simulations.

In step S104, the controller 30 stops the defrosting operation and starts the cooling operation. That is, the controller 30 starts the cooling operation by operating the compressor 1, stops the cavitation heater 37 and the radiant heater 38, and ends the defrosting of the evaporator 4. Thus, the cooling of the refrigerator 5 1 is resumed.

Controller 30, the defrosting in the first cooling operation period of time Δt from the start of the cooling run following the end of the operating period, the machine compartment fan 5 rotates per usual unit time the number of revolutions per unit time of the b number X2 Is set to a smaller rotation speed X1. The reason why the number of revolutions per unit time is reduced will be described. At time t2, the drain water generated by the defrosting is collected in the drain water evaporation dish 8, so that the heat radiation amount of the drain water evaporation condenser 2a is increased. For this reason, in time (DELTA) t after a defrost operation stop, the rotation speed per unit time of the machine room fan 5b is made lower than the time of normal operation. As a result, it is possible to realize an energy-saving operation that suppresses the power of the machine room fan 5b while securing a heat radiation amount equivalent to that in the normal state.

  In step S105, when a predetermined length of time Δt has elapsed from time t2, the process proceeds to step S106. The time Δt is a time expected to decrease until the drain water generated by the defrosting disappears or to a certain amount. As the time Δt, in the first embodiment, a predetermined fixed length can be set by examination through experiments or simulations.

In step S106, the controller 30 will continue to the first cooling operation period, in the second cooling operation period cooling operation is the period until the end of the per machine compartment fan 5 b unit time rotational speed normal The rotational speed is changed to X2.

  In the above control method, the rotation speed per unit time of the machine room fan 5b is controlled based on whether or not a predetermined fixed time Δt has elapsed from the start of the cooling operation. Since an energy-saving operation can be performed without providing a sensor for controlling the number of revolutions per hour, the cost can be reduced.

  As described above, in the present embodiment, when drain water is present, the number of revolutions per unit time of the machine room fan 5b can be lowered, so that energy saving is realized without deteriorating the performance of the refrigeration cycle. can do. Furthermore, since the rotational speed per unit time of the machine room fan 5b is lowered when drain water is present, the noise of the machine room fan 5b can be reduced.

[Embodiment 2]
The configuration of the refrigerator according to the second embodiment is substantially the same as the configuration of the refrigerator according to the first embodiment, but the control method for the machine room fan 5b is different.

  The amount of drain water generated by the defrosting operation changes depending on the operation state of the refrigerator and the surrounding environment before the defrosting operation. By changing the operation time in which the rotational speed per unit time of the machine room fan 5b after the defrosting operation is lowered according to the amount of the drain water, the drain water cold heat source can be effectively utilized.

  In addition to the functions of the refrigerator of the first embodiment, the refrigerators of the second to fifth embodiments detect or estimate the amount of drain water, and rotate the machine room fan 5b per unit time according to the amount of drain water. A function of setting a time for lowering the number (hereinafter referred to as low rotation speed time) Δt is provided.

  As the drain water increases, the heat radiation amount of the drain water evaporation condenser 2a increases. This is because the drain water promotes heat radiation in the drain water evaporation condenser 2a. Therefore, the more drain water, the longer the time during which the entire heat radiation amount of the refrigerator 51 can be maintained even if the rotational speed per unit time of the machine room fan 5b is lowered. Therefore, when there is a lot of drain water, the low rotation speed time Δt is set long, and when there is little drain water, the low rotation speed time Δt is set short. At this time, Δt may be proportional to the amount of drain water.

FIG. 6 is a structural diagram of a cross-sectional view of the refrigerator 52 according to the second embodiment.
The refrigerator 52 according to the present embodiment includes door opening / closing sensors 34a, 34b, and 34c as sensors for detecting or estimating the amount of drain water stored in the drain water evaporation tray after completion of the defrosting operation.

  Moist air that forms frost on the evaporator 4 is generated when outside air enters the cabinet by opening and closing the door. For this reason, in the operation section before the defrosting operation is started, the number of frosting increases as the number of times the door is opened and closed is longer and the door is opened longer. If the amount of frost formation is large, the amount of drain water generated by the defrosting operation increases.

  The door opening / closing sensor 34a outputs a signal indicating that the storage chamber 7a is opened when the door of the storage chamber 7a is opened, and outputs a signal indicating that the door is closed when the door of the storage chamber 7a is closed. The door opening / closing sensor 34b outputs a signal indicating that the storage chamber 7b is opened when the door of the storage chamber 7b is opened, and outputs a signal indicating that the door is closed when the door of the storage chamber 7b is closed. The door opening / closing sensor 34c outputs a signal indicating that the storage chamber 7c is opened when the door of the storage chamber 7c is opened, and outputs a signal indicating that the door is closed when the door of the storage chamber 7c is closed.

  The controller 30 obtains the low rotation speed time Δt in the current cooling operation period of the machine room fan 5b according to the output signals of the door opening / closing sensors 34a, 34b, 34c in the previous cooling operation period.

  FIG. 7 is a flowchart showing a procedure for obtaining the low rotational speed time Δt of machine room fan 5b in the second embodiment.

  Referring to FIG. 7, in step S201, the controller 30 sets the number of times Na of opening the door of the storage chamber 7a, the number of times Nb of opening the door of the storage chamber 7b, and the number of times Nc of opening the door of the storage chamber 7c to 0. Set.

  In step S202, the controller 30 sets the total time Ta when the door of the storage chamber 7a is opened, the total time Tb when the door of the storage chamber 7b is opened, and the total time Tc when the door of the storage chamber 7c is opened to 0. To do.

  In step S203, when the defrosting operation is started, the process proceeds to step S207, and when the defrosting operation is not started, the process proceeds to step S204.

  In step S204, the controller 30 obtains the number Na of opening times of the door of the storage chamber 7a and the total opening time Ta based on the output signal of the door opening / closing sensor 34a.

  In step S205, the controller 30 obtains the door opening / closing sensor 34b output signal Nb, and the total opening time Tb of the storage chamber 7b.

  In step S206, the controller 30 obtains the number Nc of times when the door of the storage chamber 7c is opened and the total time Tc of the opening based on the output signal of the door opening / closing sensor 34c.

  In step S207, when the defrosting operation is completed, the process proceeds to step S208.

  In step S208, the controller 30 obtains an added value N of Na, Nb, and Nc.

  In step S209, the controller 30 calculates an added value T of Ta, Tb, and Tc.

  In step S210, the controller 30 calculates a weighted addition value Y (= w1 × N + w2 × T) of N and T.

  In step S211, the controller 30 obtains the low rotation speed time Δt according to the magnitude of Y. For example, the low rotation speed time Δt may be set in proportion to Y.

  In step S212, when the power of the refrigerator 52 is turned off, the process ends, and when the power of the refrigerator 52 is kept on, the process returns to step S201.

  FIG. 8 is a flowchart showing the procedure of the process in step S204 of FIG. The procedure of steps S205 and S206 in FIG. 7 is the same as this.

  In step S301, when the controller 30 receives a signal indicating that the door of the storage chamber 7a is opened from the door opening / closing sensor 34a, the controller 30 advances the process to step S302.

In step S302, the controller 30 starts a timer.
In step S303, when the controller 30 receives a signal indicating that the door of the storage chamber 7a is closed from the door opening / closing sensor 34a, the controller 30 advances the process to step S304.

  In step S304, the controller 30 adds a timer value to the total time Ta when the door of the storage chamber 7a is opened.

  In step S305, the controller 30 increases the number Na of times that the door of the storage chamber 7a is opened by one.

  As described above, according to the present embodiment, it is possible to estimate the amount of drain water generated by the defrosting operation based on the output of the door opening / closing sensor and set the low rotation speed time of the machine room fan. it can.

[Embodiment 3]
The configuration of the refrigerator according to the third embodiment is the same as the configuration of the refrigerator according to the first embodiment, but the control method for the machine room fan 5b is different.

FIG. 9 is a structural diagram of a cross-sectional view of the refrigerator 53 of the third embodiment.
The refrigerator 53 of the present embodiment includes an outside air humidity sensor 33 as a sensor for detecting or estimating the amount of drain water.

The controller 30 obtains the low rotation speed time Δt in the current cooling operation period of the machine room fan 5b according to the output signal of the humidity sensor 33 in the previous cooling operation period.

  If the humidity of the outside air is high, more water vapor enters when the door is opened and closed, etc., so that the frost formation of the evaporator 4 changes depending on the humidity of the outside air. Therefore, the controller 30 lengthens the low rotational speed time Δt for decreasing the rotational speed per unit time of the machine room fan 5b if the average humidity of the outside air during the previous cooling operation period is high, and decreases if the average humidity is low. The rotation time Δt is shortened.

  FIG. 10 is a flowchart showing a procedure for obtaining the low rotational speed time Δt of machine room fan 5b in the third embodiment.

  Referring to FIG. 10, in step S <b> 401, controller 30 sets an average humidity M of outside air to 0.

  In step S402, when the defrosting operation is started, the process proceeds to step S406, and when the defrosting operation is not started, the process proceeds to step S403.

  In step S403, the controller 30 advances the process to step S404 when a predetermined time has elapsed since the previous external humidity measurement.

  In step S <b> 404, the controller 30 receives a signal representing the outside air humidity output from the outside air humidity sensor 33 and acquires the outside air humidity S.

  In step S405, the controller 30 calculates the average M of the outside air humidity up to now based on the acquired outside air humidity S.

  In step S406, when the defrosting operation is completed, the process proceeds to step S407.

  In step S407, the controller 30 obtains the low rotation speed time Δt according to the average M of the outside air humidity. For example, the low rotation speed time Δt may be set in proportion to M.

  In step S408, when the power of the refrigerator 53 is turned off, the process ends, and when the power of the refrigerator 53 is kept on, the process returns to step S401.

  As described above, according to the present embodiment, the amount of drain water generated by the defrosting operation is estimated based on the output of the outside air humidity sensor, and the low rotation time of the machine room fan can be set. it can.

[Embodiment 4]
The configuration of the refrigerator of the fourth embodiment is the same as the configuration of the refrigerator of the first embodiment, but the control method of the machine room fan 5b is different, so that point will be described.

FIG. 11 is a structural diagram of a cross-sectional view of the refrigerator 54 according to the fourth embodiment.
The refrigerator 54 of the present embodiment includes the rotation speed sensor 31 of the compressor 1 as a sensor that detects or estimates the amount of drain water. The rotation speed sensor 31 detects the rotation speed (rotational speed) of the compressor 1 per unit time.

  The controller 30 obtains the current low rotational speed time Δt of the machine room fan 5b in accordance with the output signal of the rotational speed sensor 31 of the compressor 1 in the immediately preceding cooling operation period.

  When the number of rotations per unit time of the compressor 1 is high, the compressor 1 is operated with a large refrigerating capacity proportional thereto, so that more cooling is performed. The higher the number of revolutions per unit time of the compressor 1 during the cooling operation period before the defrosting operation, the larger the cooling operation is performed, so the amount of frost formation on the evaporator 4 also increases. Therefore, if the total number of revolutions per unit time of the compressor 1 during the previous cooling operation period is high, the controller 30 increases the low revolution time Δt that lowers the revolutions per unit time of the machine room fan 5b. If the total number of revolutions per unit time of the compressor 1 during the previous cooling operation period is low, the low revolution number time Δt for lowering the revolution number per unit time of the machine room fan 5b is shortened.

  FIG. 12 is a flowchart showing a procedure for obtaining the low rotational speed time Δt of machine room fan 5b in the fourth embodiment.

  Referring to FIG. 12, in step S <b> 501, controller 30 sets a total number R of rotations of compressor 1 to zero.

  In step S502, when the defrosting operation is started, the process proceeds to step S506, and when the defrosting operation is not started, the process proceeds to step S503.

  In step S503, the controller 30 advances the process to step S504 when the unit time has elapsed since the previous acquisition of the rotational speed P of the compressor 1 per unit time.

  In step S <b> 504, the controller 30 receives a signal representing the rotational speed per unit time of the compressor 1 output from the rotational speed sensor 31, and obtains the rotational speed P of the compressor 1 per unit time.

  In step S505, the controller 30 adds the acquired rotation speed P per unit time to the total rotation speed R of the compressor 1.

  In step S506, when the defrosting operation is completed, the process proceeds to step S507.

  In step S507, the controller 30 obtains the low revolution time Δt in accordance with the magnitude of the total revolution R of the compressor 1. For example, the low rotation speed time Δt may be set in proportion to R.

  In step S508, when the power of the refrigerator 54 is turned off, the process ends, and when the power of the refrigerator 54 is kept on, the process returns to step S501.

As described above, according to the present embodiment, the amount of drain water generated by the defrosting operation is estimated based on the output of the rotation speed sensor of the compressor, and the low rotation speed time of the machine room fan is set. can do.

  Note that, instead of the total number of revolutions per unit time of the compressor, the low revolution number time Δt may be obtained based on the average number of revolutions per unit time of the compressor.

[Embodiment 5]
The configuration of the refrigerator according to the fifth embodiment is the same as the configuration of the refrigerator according to the first embodiment, but the control method of the machine room fan 5b is different, so that point will be described.

FIG. 13 is a structural diagram of a cross-sectional view of refrigerator 55 according to the fifth embodiment.
The refrigerator 55 of the present embodiment includes a temperature sensor 32 that detects the temperature of the evaporator as a sensor that detects or estimates the amount of drain water.

  During the defrosting operation, the heaters 37 and 38 installed near the evaporator 4 are used for defrosting, so that the temperature gradually rises from when the heaters 37 and 38 are energized. At this time, if the amount of frost formation is large, the heat capacity of the frost formation increases, so the temperature rise of the evaporator 4 is delayed.

  FIG. 14 is a diagram showing the relationship between the amount of frost formation and the rate of temperature rise of the evaporator 4 during the defrosting operation.

As shown in FIG. 14, when the amount of frost formation is small, the speed of the evaporator temperature rise is fast during the defrosting operation, and when the amount of frost formation is large, the speed of the evaporator temperature rise is slow during the defrosting operation. .

  Therefore, the amount of frost formation can be detected by the rate of temperature rise of the evaporator 4. Since the amount of drain water increases as the frost amount increases during the defrosting operation, the amount of drain water can also be detected by detecting the rate of temperature rise of the evaporator 4.

  In the present embodiment, the controller 30 obtains the time td required for the temperature of the evaporator 4 detected by the temperature sensor 32 to increase by ΔTdef after the start of the defrosting operation as the temperature increase rate of the evaporator 4. . Based on td in the previous defrosting operation period, the controller 30 obtains the low rotation speed time Δt in the current cooling operation period. If td is long (that is, if the temperature increase rate is low), the amount of frost formation is large. Therefore, the controller 30 sets the low rotation time Δt to be long, and if td is short (that is, if the temperature increase rate is large) Since the amount of frost is small, the low revolution time Δt is set short.

  FIG. 15 is a flowchart showing the procedure for calculating the low rotation speed time Δt of machine room fan 5b in the fifth embodiment.

  Referring to FIG. 15, when the defrosting operation is started in step S601, the process proceeds to step S602.

In step S602, the controller 30 starts a timer.
In step S <b> 603, the controller 30 receives a signal representing the temperature of the evaporator 4 output from the temperature sensor 32 and acquires the temperature of the evaporator 4. When the temperature of the evaporator 4 increases by the predetermined value ΔTdef from the temperature at the start of the defrosting operation, the controller 30 advances the process to step S604.

  In step S604, the controller 30 sets the timer value to the temperature rise required time td.

  In step S605, the controller 30 obtains the low rotation speed time Δt according to the magnitude of the temperature rise required time td. For example, the low rotation speed time Δt may be set in proportion to td.

  In step S606, when the defrosting operation is finished, the process proceeds to step S607.

  In step S607, when the power of the refrigerator 55 is turned off, the process ends, and when the power of the refrigerator 55 is kept on, the process returns to step S501.

  As described above, according to the present embodiment, the amount of drain water generated by the defrosting operation is estimated based on the output of the temperature sensor that detects the temperature of the evaporator, and the low rotation speed of the machine room fan is estimated. You can set the time.

(Modification)
The present invention is not limited to the above embodiment, and includes, for example, the following modifications.
(1) Use of a plurality of sensors In the above-described embodiment, the low rotation time Δt of the machine room fan is obtained based on the output of one type of sensor, but based on the combination of the outputs of the plurality of types of sensors. The low rotation time Δt of the machine room fan may be obtained.
(2) In the machine room fan 5 b rotational speed of adjustment above embodiment of, in the whole of the first cooling operation period of time Δt from the end to the subsequent cooling operation start of the defrosting operation period, the machine compartment fan 5 Although the rotation speed per unit time of b is set to the rotation speed X1 smaller than the normal rotation speed X2 per unit time, it is not limited to this.

In the second the number of revolutions per machine compartment fan 5 b unit time of the cooling operation period as the rotational speed X2 per ordinary unit of time, a portion of the period of the first cooling operation period, the machine compartment fan 5 b the number of revolutions per unit time is set to a small rotational speed X1 than the rotation number X2 per ordinary unit of time, in a period other than the part of the first cooling operation period, the machine compartment fan 5 b The rotational speed per unit time may be set to the same rotational speed as or larger than the normal rotational speed X2 per unit time. Preferably, the first cooling operation period and the second cooling operation period, the energy required in this way to operate the machine compartment fan 5 b is, the first cooling operation period and the second cooling operation period in total, it may be made smaller than the energy required to operate the number of revolutions per unit time of the machine compartment fan 5 b at a rotation number X2 per usual unit time.

Further, the rotational speed is a fixed value of at least a portion of the per machine compartment fan 5 b units of time of the first cooling operation period X1, number of revolutions per unit time of the machine compartment fan 5 b of the second cooling operation period It is not limited to the fixed value X2. These values are not necessary to be a fixed value, the rotational speed of at least per unit time of a portion of the machine compartment fan 5 b of the first cooling operation period, the machine compartment fan 5 of the second cooling operation period What is necessary is just to satisfy | fill the condition that it is smaller than the rotation speed per unit time of b.

Further, in at least a part of the first cooling operation period it may be one that stops the machine compartment fan 5 b.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 compressor, 2 condenser, 2a drain water evaporating condenser, 2b machine room condenser, 2c side pipe, 3 pressure reducer, 4 evaporator, 5 fans, 5a refrigerator fan, 5b machine room fan, 6 Air volume regulator, 7a, 7b, 7c Storage room, 8 Drain water evaporation tray, 9 Drain water, 31 Rotational speed sensor, 32 Temperature sensor, 33 Outside air humidity sensor, 34a, 34b, 34c Door open / close sensor, 37 Catic heater 38 Radiant heater, 51-55 Refrigerator, 81 Refrigeration cycle apparatus.

Claims (8)

A refrigerator,
A refrigeration cycle apparatus configured to circulate the refrigerant in the order of the compressor, the first condenser, the second condenser, the decompression device, and the evaporator during the cooling operation period;
A drain pan for storing drain water generated in the evaporator, wherein the first condenser is accommodated in the drain pan,
The refrigerator further includes
A fan for sending air to the second condenser;
The cooling operation period includes a first cooling operation period that follows the defrosting operation period, and a second cooling operation period that follows the first cooling operation period,
The rotational speed of the fan during the first cooling operation period is a first constant, and the rotational speed of the fan during the second cooling operation period is a second greater than the first constant. Ri certain number der,
The refrigerator, wherein the length of the first cooling operation period is determined before the start of the first cooling operation period .   The refrigerator according to claim 1, wherein the length of the first cooling operation period changes according to the amount of drain water stored in the drain pan after the end of the defrosting operation period. A sensor for detecting opening and closing of the refrigerator door;
Based on the output of the sensor, the number of times the door was opened and the time when the door was opened during the previous cooling operation period were obtained, and the number of times the door was opened and the time when the door was opened were The refrigerator according to claim 1, further comprising a control unit that determines a length of one cooling operation period. A sensor for detecting humidity of air outside the refrigerator;
Based on the output of the sensor, the average of the humidity of the external air in the previous cooling operation period is obtained, and the length of the first cooling operation period is determined based on the average of the humidity of the external air. The refrigerator according to claim 1, further comprising a control unit. A sensor for detecting the number of rotations per unit time of the compressor;
Based on the output of the sensor, find the average or total number of revolutions per unit time of the compressor during the previous cooling operation period, based on the average or total number of revolutions of the compressor per unit time, The refrigerator according to claim 1, further comprising a control unit that determines a length of the first cooling operation period. A sensor for detecting the temperature of the evaporator;
Control for obtaining a change rate of the temperature of the evaporator during the previous defrosting operation period based on the output of the sensor, and determining a length of the first cooling operation period based on the change rate of the temperature. The refrigerator according to claim 1, further comprising a unit. A heater,
The refrigerator according to claim 1, wherein the heater operates during the defrosting operation period, and the heater stops during the cooling operation period.   The refrigerator according to claim 1, wherein the compressor is stopped during the defrosting operation period.

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