JP2011252681A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator which is reduced in power consumption and improved in freshness-preservability by performing a defrosting operation according to an amount of frosting on a cooler.SOLUTION: The refrigerator includes a storage chamber installed in a refrigerator body, the cooler which exchanges heat with air to be sent to the storage chamber, a compressor which is connected to the cooler by a refrigerant pipe, air blowing unit of sending the air having exchanged heat by the cooler, a defrosting heater which melts frost sticking on the cooler, and a temperature detection unit which is arranged in the cooler chamber provided with the cooler. During a defrosting operation in which the compressor is stopped and the defrosting heater is placed in operation, the air blowing unit is placed in operation, a temperature gradient in a temperature zone lower than the melting temperature of frost is read from detected temperature of the temperature detecting unit, an amount of frosting on the cooler is estimated based upon the temperature gradient, and a time defrosting operation according to the estimated amount of frosting is performed.

Description

  The present invention relates to a refrigerator.

  In recent years, refrigerators are desired to improve energy saving. In particular, in the defrosting operation for melting the frost grown on the cooler, the cooler is heated by the defrost heater to melt the frost, so that efficiency is required.

  As conventional technology, Patent Document 1 includes a defrosting operation unit that energizes the defrosting heater and disconnects the defrosting heater when the defrosting end determination temperature is detected based on the defrosting temperature detection unit, Outside temperature detection means for detecting the temperature around the refrigerator, temperature change rate calculation means for calculating the rate of change of the detected temperature of the defrost temperature detection means after the start of energization of the defrost heater, and this temperature change rate calculation means The frost formation amount estimation means for estimating the frost formation amount based on the temperature change rate by the outside air temperature detection means and the estimated frost formation amount by the frost formation amount estimation means is determined based on the frost formation amount estimation means. A defrosting device for a refrigerator comprising a defrosting end determination temperature determining unit is disclosed.

JP-A-8-94234

  However, in the configuration described in Patent Document 1, since heat propagation is due to natural convection, it takes time to estimate the amount of frost formation, resulting in prolonged defrosting operation. Then, the warmed air flows into the storage room, which causes a decrease in humidity in the storage room, and may reduce the freshness of stored items. Furthermore, there is a problem that it takes time to recool after the defrosting operation.

  Then, in order to solve the said subject, this invention aims at providing the refrigerator which reduced the power consumption and improved the freshness by performing the defrost operation according to the amount of frost formation of a cooler. And

  In order to achieve the above object, the present invention provides a storage chamber installed in a refrigerator body, a cooler for exchanging heat to the air sent to the storage chamber, a compressor connected to the cooler by refrigerant piping, Blowing means for blowing air exchanged heat by a cooler to the storage chamber, a defrosting heater for melting frost attached to the cooler, and a temperature detection means arranged in the cooler chamber provided with the cooler. And during the defrosting operation in which the compressor is stopped and the defrosting heater is operated, the air blowing unit is operated, and a temperature gradient in a temperature range lower than the melting temperature of the frost is detected from the detected temperature of the temperature detecting unit. Reading, estimating a frost formation amount of the cooler based on the temperature gradient, and performing a defrosting operation for a time according to the estimated frost formation amount.

  The temperature gradient is based on a rate of temperature increase within a certain time or an elapsed time until the temperature rises.

  In addition, a storage chamber installed in the refrigerator main body, a cooler for exchanging heat to the air to be sent to the storage chamber, a compressor connected to the cooler by refrigerant piping, and the air for heat exchange by the cooler A compressor for supplying air to the chamber, a pipe heater installed along the fin of the cooler, and a temperature detector for detecting temperatures of at least two locations where the frosting amount of the cooler is different. After a definite period of time has elapsed since the start of the defrosting operation in which the pipe heater is turned off and the pipe heater is energized, the frost formation amount of the cooler is estimated on the basis of the temperature difference at the location where the frost formation amount is different, and the estimated The defrosting operation is performed for a time corresponding to the amount of frost formation.

  In addition, a storage chamber installed in the refrigerator main body, a cooler for exchanging heat to the air to be sent to the storage chamber, a compressor connected to the cooler by refrigerant piping, and the air for heat exchange by the cooler Blower means for blowing air to the chamber, a defrost heater for melting frost attached to the cooler, a light emitter for irradiation between the fins of the cooler, and an illuminance detection means for detecting the illuminance between the fins of the cooler The amount of frost formation between the fins of the cooler is estimated based on the detection value of the illuminance detection means, and the compressor is stopped for a time corresponding to the estimated amount of frost formation. A defrosting operation for operating the heater is performed.

  In addition, a plurality of the light emitters are arranged so as to irradiate between different fins of the cooler, and the distribution of frost formation between the different fins of the cooler is estimated based on a detection value of the illuminance detection means. Features.

  In addition, a storage chamber installed in the refrigerator main body, a cooler for exchanging heat to the air to be sent to the storage chamber, a compressor connected to the cooler by refrigerant piping, and the air for heat exchange by the cooler A blower that blows air to the chamber, a defrost heater that melts frost attached to the cooler, and a wind speed sensor that detects the wind speed on the upstream side and the downstream side of the cooler, and is detected by the wind speed sensor. The frost formation amount of the cooler is estimated from the difference in wind speed between the upstream side and the downstream side of the cooler, and the compressor is stopped for a time corresponding to the estimated frost formation amount, and the defrost heater is operated. A defrosting operation is performed.

  In addition, a storage chamber installed in the refrigerator main body, a cooler for exchanging heat to the air to be sent to the storage chamber, a compressor connected to the cooler by refrigerant piping, and the air for heat exchange by the cooler An air blowing means for blowing air to the chamber, a defrost heater for melting frost attached to the cooler, and a sound wave sensor for detecting a distance by receiving a sound wave transmitted toward the fin of the cooler, Defrosting by estimating the frost formation amount of the cooler based on the distance to the fin detected by the sonic sensor, and stopping the compressor and operating the defrost heater for a time corresponding to the estimated frost formation amount It is characterized by performing driving.

  In addition, a storage chamber installed in the refrigerator main body, a cooler for exchanging heat to the air to be sent to the storage chamber, a compressor connected to the cooler by refrigerant piping, and the air for heat exchange by the cooler A blower for blowing air to the chamber, a defrost heater for melting frost attached to the cooler, and a wind pressure sensor for detecting the wind pressure on the upstream side and the downstream side of the cooler, and detected by the wind pressure sensor. The frost formation amount of the cooler is estimated from the pressure difference between the upstream side and the downstream side of the cooler, and the compressor is stopped for a time corresponding to the estimated frost formation amount, and the defrost heater is operated. A defrosting operation is performed.

  ADVANTAGE OF THE INVENTION According to this invention, the power consumption can be reduced by performing the defrost operation according to the amount of frost formation of a cooler, and the refrigerator which improved freshness can be provided.

The schematic longitudinal cross-sectional view of the refrigerator which concerns on Example 1 of this invention. The figure which shows the relationship between the defrost time in Example 1, and the change of sensor detection temperature. The enlarged view of the defrosting time initial stage in FIG. 2a. The schematic perspective view of the cooler concerning Example 2 of the present invention. The figure which shows the relationship between the defrost time in Example 2, and the change of sensor detection temperature. The schematic front view of the cooler concerning Example 3 of the present invention. The figure which shows the state which frosted to the cooler in Example 3. FIG. FIG. 10 is a diagram illustrating a relationship between an example of sensor arrangement and sensitivity in Example 3. The schematic perspective view of the cooler concerning Example 4 of the present invention. Schematic explaining the frost formation detection of the cooler which concerns on Example 5 of this invention. Schematic explaining the frost formation detection of the cooler which concerns on Example 5 of this invention. The schematic perspective view of the cooler concerning Example 6 of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the configuration of the entire refrigerator will be described. As shown in FIG. 1, the refrigerator of a present Example has the storage chamber divided and installed in the refrigerator main body 1 in plurality. These storage rooms are arranged from the top in order of frequency of use, and are configured to improve the convenience of the refrigerator. For example, the refrigerator compartment 14, the freezing temperature zone 15 and the vegetable compartment 16 are provided in order from the top, and the storage compartments in different temperature zones are partitioned by heat insulating partition walls 19 and 20. That is, the refrigerator compartment 14 and the refrigeration temperature zone chamber 15 are partitioned adiabatically by the heat insulating partition wall 19, and the refrigeration temperature zone chamber 15 and the vegetable compartment 16 are adiabatically partitioned by the heat insulating partition wall 20. .

  The freezing temperature zone chamber 15 is maintained in a freezing temperature zone of, for example, about −6 to −40 ° C., and is divided into an ice making chamber 18 for generating ice and a freezing chamber 17 for freezing and storing stored items. The refrigerator compartment 14 and the vegetable compartment 16 are configured by controlling the temperature in a refrigeration temperature range of about 0 ° C. to 10 ° C., for example.

  The cooler chamber 2 is disposed behind the freezing temperature zone chamber 15. The cooler chamber 2 is provided with a cooler 13 for exchanging heat of air sent to each storage chamber. In addition, an internal fan 21 (air blowing means) that blows and circulates cold air exchanged by the cooler 13 is installed in the cooler chamber 2 and above the cooler 13. Specifically, cold air is sent to the freezing temperature zone chamber 15, the refrigerator compartment 14, and the vegetable compartment 16, and cold air circulation is performed.

  The compressor 12 that constitutes the refrigeration cycle together with the cooler 13 is located in the machine room 30 on the back side of the refrigerator body 1 and is connected to a condenser or capillary tube (not shown) by a refrigerant pipe. The rotation speed of the compressor 12 is controlled by the detection values of the refrigeration temperature zone chamber temperature detection means 25 and the refrigeration temperature zone chamber temperature detection means 26. The refrigeration temperature zone chamber temperature detection means 25 is provided in the refrigeration temperature zone chamber 15 and detects the temperature in the refrigeration temperature zone chamber 15. The refrigeration temperature zone temperature detecting means 26 is provided in the refrigeration chamber 14 (refrigeration temperature zone) and detects the temperature of the refrigeration chamber 14. The operation control of the refrigeration cycle including the compressor 12 is performed by the control device 11 provided at the upper rear of the refrigerator body 1.

  The cool air generated by the cooler 13 is sent from the cooler chamber 2 to each storage chamber by the internal fan 21. Here, the 1st electric damper 22 and the 2nd electric damper 23 are each attached to the cold air | gas channel | path connected to each store room. A second electric damper 23 is installed in the refrigerator compartment cold air passage 3 to control the amount of air blown to the refrigerator compartment 14. A first electric damper 22 is installed in the freezing temperature zone cold air passage 4 to control the amount of air blown to the freezing temperature zone 15.

  When the temperature in each storage chamber is detected by the freezing temperature zone temperature detecting means 25 and the refrigeration temperature zone temperature detecting means 26, the detected value is input to the control device 11. The control device 11 controls the opening and closing of the first electric damper 22 and the second electric damper 23, the operation of the internal fan 21, the energization of each heater, and the operation of the refrigeration cycle.

  Moreover, the frost adhering to the cooler 13 is periodically melted by a defrost heater 32 provided at the lower part of the cooler 13. The defrost water generated by energizing the defrost heater 32 and melting the frost in the cooler 13 is dropped from the drain pipe 33 to the machine room 30 where the compressor 12 is installed. Above the compressor 12 installed in the machine room 30, an evaporating dish 31 is installed and receives defrost water from the drain pipe 33 to evaporate.

  Next, the defrosting operation will be described. In the defrosting operation, the compressor 12 is stopped and the defrosting heater 32 is operated. FIG. 2 a shows the relationship between the temperature change detected by the thermistor 35 (temperature detection means) that detects the temperature of the cooler 13 and the defrosting time. As shown in FIG. 2a, the defrosting operation takes a longer time as the amount of frost on the cooler 13 increases. The change in the detected temperature increases with time until the frost melting temperature. When the melting temperature is reached, frost begins to melt and time passes at a constant temperature. Thereafter, the temperature rises again when the frost is melted, but the temperature is lowered by stopping the defrost heater 32 and operating the compressor 12.

  Here, paying attention to the initial temperature change of the defrosting operation, as shown in FIG. 2b, the temperature rises in the cooler 13 and the cooler chamber 2 become smaller as the amount of frost formation increases. Therefore, the temperature gradient is also reduced. The relationship between this temperature gradient and the amount of frost formation can be grasped by preliminary experiments. A thermistor 35 installed in the cooler chamber 2 and provided in the vicinity of the cooler 13 compares the detected temperature at the start of energization of the defrost heater 32 with the detected temperature of the thermistor 35 after a predetermined time has elapsed. And the temperature gradient during a defrost operation is calculated | required and the amount of frost formation is estimated by the magnitude | size of the inclination. The detected temperature after the elapse of a certain time is set to a temperature equal to or lower than the melting temperature of frost. Moreover, even if the temperature gradient is based on the rate of temperature increase within a certain time, the same effect can be obtained. In this case, the operation time of the internal fan 21 is not prolonged, and it is possible to suppress the air warmed by the defrost heater 32 from flowing into each storage room more than necessary. Furthermore, if the internal fan 21 is operated only during the initial stage of the defrosting operation, the cooling energy of the frost attached to the cooler 13 can be converted into the cooling energy of each storage chamber, so that energy efficiency is good.

  At this time, the internal fan 21 is also rotated at the same time for a certain time from the start of energization to the defrost heater 32. At this time, the temperature around the thermistor 35 largely changes due to the difference in the amount of frost formation due to forced convection, so that it becomes easy to determine the amount of frost formation.

  Moreover, when it is judged that the amount of frost formation is small, an extra defrost operation can be excluded by postponing without starting a defrost operation.

  In addition, when it is determined that the amount of frost formation is small at the start of the defrosting operation, it is possible to eliminate the extra defrosting operation by setting the defrosting end determination temperature by the temperature detection means to be shifted lower than the normal time. it can.

  According to the present embodiment, by estimating the amount of frost formation from the temperature change in the initial stage after the start of the defrosting operation, it becomes possible to control the energization time of the subsequent defrosting heater 32, change the defrosting termination condition, and the like. Efficiency of defrosting operation becomes possible.

  Next, a second embodiment will be described with reference to FIGS. Note that the description of the same configuration as that of the first embodiment is omitted.

  First, as shown in FIG. 3, the cooler 13 a includes a pipe heater 41. The pipe heater 41 is arranged in a plurality of stages along the fins of each stage of the cooler 13a, and has a meandering shape in which the plurality of stages of pipes are connected by a U-shaped tube.

  In the present embodiment, in addition to the radiant heat from the defrost heater 32 described in the first embodiment, the heat transfer fins of the cooler 13a can be directly heated by the pipe heater 41. Moreover, the 1st thermistor 35a and the 2nd thermistor 35b are each provided in the position which has a difference in the amount of frost formation. The first thermistor 35a is provided at the upper part of the cooler 13a, and the second thermistor 35b is provided at the lower part of the cooler 13a. Here, the cold air circulated through each storage chamber flows from the lower part to the upper part of the cooler 13a. That is, since high humidity air contacts the lower part of the cooler 13a, a lot of frost grows in the lower part of the cooler 13a. On the other hand, the upper part of the cooler 13a comes in contact with air that has flowed from the lower part and has a low humidity, so that the growth of frost is relatively small.

  In this embodiment, only the pipe heater 41 is energized without operating the defrost heater 32 at the start of the defrost operation, and the first thermistor 35a and the second thermistor 35a after a certain time has elapsed since the start of the defrost operation. The detected temperature of the thermistor 35b is compared. At this time, more energy is consumed at the temperature of the portion where the frosting amount of the cooler 13a is larger to melt the frost. Therefore, as shown in FIG. 4, the temperature lower than the site | part with few amounts of frost formation is maintained. Therefore, the amount of frost formation is estimated based on the difference between the detected temperatures of the first thermistor 35a and the second thermistor 35b after the elapse of a certain time from the start of the defrosting operation, and the time control of the defrosting operation is performed as in the first embodiment. To use.

  Next, Example 3 will be described with reference to FIGS. 5a and 5b. Note that the description of the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 5a, the refrigerator of the present embodiment includes a light emitter 45 that emits light between the fins of the cooler 13b, and an illuminance sensor 46 that is an illuminance detection unit that detects the illuminance between the fins of the cooler 13b. . The light emitter 45 and the illuminance sensor 46 are arranged so as to face each other across the cooler 13b so as not to be blocked by the fins of the cooler 13. The light emitter 45 is controlled by the control device 11 (see FIG. 1), and detection information of the illuminance sensor 46 is input to the control device 11.

  In the present embodiment, the amount of frost formation between the fins of the cooler 13b is estimated based on the detection value of the illuminance sensor 46, and the defrosting operation is performed for a time corresponding to the estimated amount of frost formation. As more detailed control, the light emitter 45 is caused to emit light at regular intervals, and the illuminance sensor 46 measures the illuminance. Between the light emitter 45 and the illuminance sensor 46, the cooler 13b is located. When the cooler 13b is in a frosting state, a frosting portion 47 appears as shown in FIG. 5b. When the frosting part 47 is provided, the number of obstacles between the light emitter 45 and the illuminance sensor 46 increases as compared with the case where frosting is not performed (in the case of FIG. 5a). As a result, the detected illuminance decreases. For this reason, the amount of frost formation between the light emitter 45 and the illuminance sensor 46, that is, between the fins of the cooler 13b, can be estimated based on the detection value of the illuminance sensor 46. Therefore, by investigating the relationship between the measurement site and the total amount of frost formation in advance, it can be used for time control of the defrosting operation or the defrosting start determination.

  Further, a plurality of light emitters are arranged so as to irradiate light between different fins of the cooler 13b, and the distribution of frost formation between the different fins of the cooler 13b is estimated based on the detection value of the illuminance sensor 46. As shown in FIG. 6, the light emitters 45a, 45b, 45c, 45d, and 45e are arranged so as to irradiate between different fins. And the optical sensors 46a, 46b, 46c, 46d, and 46e are arrange | positioned through the cooler 13b so that each light-emitting body may be opposed. Thereby, it becomes possible to estimate the distribution of the frost amount of the entire cooler 13b based on the illuminance distribution, and the defrosting operation can be performed after grasping the more accurate frost amount.

  Next, Example 4 will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 7, the refrigerator of the present embodiment includes a wind speed sensor that detects the upstream and downstream wind speeds of the cooler 13c, and the upstream and downstream sides of the cooler 13c detected by the wind speed sensor. The frost formation amount of the cooler 13c is estimated based on the wind speed difference, and the defrosting operation is performed for a time corresponding to the estimated frost formation amount.

  The wind speed sensor 51 detects the wind speed on the leeward side of the cool air flow generated by the operation of the internal fan 21. The wind speed sensor 52 detects the wind speed on the windward side of the cool air flow generated by the operation of the internal fan 21. Detection information of the wind speed sensors 51 and 52 is input to the control device 11 (see FIG. 1). In the present embodiment, the wind speeds detected by the wind speed sensors 51 and 52 during the operation of the internal fan 21 are compared. When the cooler 13 is in a frosting state, the windage loss increases as the distance between the fins, that is, the air passage gradually narrows according to the amount of frost formation. For this reason, the difference between the detection amounts of the wind speed sensors 51 and 52 increases. Therefore, it is possible to estimate the amount of frost formation based on the difference between the detection amounts of the wind speed sensors 51 and 52 and use it for controlling the defrosting operation time or determining the start of defrosting.

  Next, Example 5 will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 8, the refrigerator of this embodiment includes a sound wave sensor 55 that detects a distance by receiving sound waves transmitted toward the fins 56 of the cooler, and the distance to the fins 56 detected by the sound wave sensor 55. The frost formation amount of the cooler is estimated based on the above, and the defrosting operation is performed for a time corresponding to the estimated frost formation amount.

  The sonic sensor 55 is disposed to face the flat portion of the fin 56 of the cooler. The sound wave sensor 55 includes a transmitter 55a that transmits a sound wave and a receiver 55b that receives a sound wave transmitted and reflected from the transmitter 55a. Detection information of the sonic sensor 55 is input to the control device 11. The sound wave sensor 55 transmits and receives sound waves and measures the distance to the target. Thereby, the distance to the fin 56 is measured. When the cooler is in a frosting state as shown in FIG. 8b, the distance to the fin 56 surface is shortened by the thickness of the frost. Therefore, the total amount of frost formation can be estimated by measuring the frost thickness from the measured distance and specifying the relationship between the detection site and the total amount of frost formation in advance. Thereby, it becomes possible to utilize for control of defrost operation time, or defrost start determination.

  Next, Example 6 will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 9, the refrigerator of the present embodiment includes pressure sensors that respectively detect the wind pressure on the upstream side and the downstream side of the cooler, and the pressure difference between the upstream side and the downstream side of the cooler detected by this pressure sensor. The amount of frost formation of the cooler is estimated by the above, and the defrosting operation is performed for a time corresponding to the estimated amount of frost formation.

  The pressure sensor 61 detects the wind pressure on the leeward side of the cold air flow generated by the operation of the internal fan 21. The pressure sensor 62 detects the wind pressure on the windward side of the cold air flow generated by the operation of the internal fan 21. Detection information of the pressure sensors 61 and 62 is input to the control device 11 (see FIG. 1). In the present embodiment, the wind pressures detected by the pressure sensors 61 and 62 during the operation of the internal fan 21 are compared. When the cooler 13 is in a frosting state, the windage loss increases as the distance between the fins, that is, the air passage gradually narrows according to the amount of frost formation. Therefore, the difference between the detection amounts of the pressure sensors 61 and 62 increases. Therefore, it is possible to estimate the amount of frost formation based on the difference between the detection amounts of the pressure sensors 61 and 62 and use it for controlling the defrosting operation time or determining the start of defrosting.

  As described above, each embodiment suppresses wasteful defrosting operation and prevents the rise in the internal temperature, thereby improving the freshness and at the same time preventing wasteful energization of the defrosting heater. Reduction can be achieved.

DESCRIPTION OF SYMBOLS 1 Refrigerator body 2 Cooler room 3 Refrigeration room cold air passage 4 Freezing temperature zone room cold air passage 11 Control device 12 Compressor 13, 13a, 13b, 13c, 13d Cooler 14 Refrigerating room (refrigeration temperature zone room)
15 Freezing temperature zone 16 Vegetable room 17 Freezing room 18 Ice making room 19, 20 Insulation partition wall 21 Fan in the chamber (air blowing means)
22 1st electric damper 23 2nd electric damper 25 Freezing temperature zone room temperature detection means 26 Refrigeration temperature zone room temperature detection means 30 Machine room 31 Evaporating dish 32 Defrost heater 33 Drain pipe 35 Thermistor (temperature detection means)
35a First thermistor 35b Second thermistor 41 Pipe heater 45 Light emitter 46 Illuminance sensor 47 Frosting part 51, 52 Wind speed sensor 55 Sound wave sensor 56 Fin 61, 62 Pressure sensor

Claims (8)

A storage room installed in the refrigerator main body, a cooler for exchanging heat to the air sent to the storage room, a compressor connected to the cooler and a refrigerant pipe, and air exchanged for heat by the cooler to the storage room An air blowing means for blowing air, a defrost heater for melting frost attached to the cooler, and a temperature detection means arranged in a cooler chamber provided with the cooler,
During the defrosting operation in which the compressor is stopped and the defrosting heater is operated, the air blowing unit is operated, and a temperature gradient in a temperature zone lower than the melting temperature of frost is read from the detected temperature of the temperature detecting unit, A refrigerator characterized by estimating a frost formation amount of the cooler based on the temperature gradient and performing a defrosting operation for a time according to the estimated frost formation amount.   2. The refrigerator according to claim 1, wherein the temperature gradient is based on a temperature increase rate within a fixed time or an elapsed time until the temperature rises. A storage room installed in the refrigerator main body, a cooler for exchanging heat to the air sent to the storage room, a compressor connected to the cooler and a refrigerant pipe, and air exchanged for heat by the cooler to the storage room Blower means for blowing air, a pipe heater installed along the fins of the cooler, and temperature detection means for detecting temperatures of at least two locations where the frosting amount of the cooler is different, respectively.
After a certain period of time has elapsed since the start of the defrosting operation in which the compressor is stopped and the pipe heater is energized, the frost formation amount of the cooler is estimated based on the temperature difference between the portions where the frost formation amount is different, The refrigerator characterized by performing the time defrosting operation according to the estimated amount of frost formation. A storage room installed in the refrigerator main body, a cooler for exchanging heat to the air sent to the storage room, a compressor connected to the cooler and a refrigerant pipe, and air exchanged for heat by the cooler to the storage room A blowing means for blowing air, a defrosting heater for melting frost attached to the cooler, a light emitter for irradiation between the fins of the cooler, and an illuminance detection means for detecting the illuminance between the fins of the cooler. Prepared,
The amount of frost formation between the fins of the cooler is estimated based on the detection value of the illuminance detection means, the compressor is stopped for a time corresponding to the estimated amount of frost formation, and the defrost heater is operated. A refrigerator characterized by performing a defrosting operation.   5. The light emitting device according to claim 4, wherein a plurality of the light emitters are arranged so as to irradiate between different fins of the cooler, and a distribution of frost formation amount between the different fins of the cooler is estimated based on a detection value of the illuminance detection means. A refrigerator characterized by that. A storage room installed in the refrigerator main body, a cooler for exchanging heat to the air sent to the storage room, a compressor connected to the cooler and a refrigerant pipe, and air exchanged for heat by the cooler to the storage room An air blowing means for blowing air, a defrost heater for melting frost attached to the cooler, and a wind speed sensor for detecting the wind speed on the upstream side and the downstream side of the cooler,
The frost formation amount of the cooler is estimated based on the difference in wind speed between the upstream side and the downstream side of the cooler detected by the wind speed sensor, and the compressor is stopped for a time corresponding to the estimated frost formation amount. The refrigerator characterized by performing the defrost operation which drives a defrost heater. A storage room installed in the refrigerator main body, a cooler for exchanging heat to the air sent to the storage room, a compressor connected to the cooler and a refrigerant pipe, and air exchanged for heat by the cooler to the storage room An air blowing means for blowing air, a defrost heater for melting frost attached to the cooler, and a sound wave sensor for detecting a distance by receiving a sound wave transmitted toward the fin of the cooler,
The frosting amount of the cooler is estimated based on the distance to the fin detected by the acoustic wave sensor, and the compressor is stopped and the defrosting heater is operated for a time corresponding to the estimated frosting amount. A refrigerator characterized by performing frost operation. A storage room installed in the refrigerator main body, a cooler for exchanging heat to the air sent to the storage room, a compressor connected to the cooler and a refrigerant pipe, and air exchanged for heat by the cooler to the storage room An air blowing means for blowing air, a defrost heater for melting frost attached to the cooler, and a wind pressure sensor for detecting wind pressure on the upstream side and the downstream side of the cooler,
The frost formation amount of the cooler is estimated from the pressure difference between the upstream side and the downstream side of the cooler detected by the wind pressure sensor, and the compressor is stopped for a time corresponding to the estimated frost formation amount. The refrigerator characterized by performing the defrost operation which drives a defrost heater.

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