JP2007292422A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption in defrosting an evaporator in a refrigerator. <P>SOLUTION: The refrigerator comprises a refrigerating cycle constituting an annular refrigerant passage by piping with a compressor 105, a condenser 106, a pressure reducer 107 and an evaporator 110 sequentially provided in a heat insulating box body 101; a defrosting heater 111 defrosting the evaporator 110; an evaporator temperature detecting means 112 detecting the temperature of the evaporator 110; and a control means 113 for controlling defrosting. The control means 113 terminates defrosting when the evaporator temperature detecting means 112 detects a first set temperature or higher, and reduces output to the defrosting heater 111 when the evaporator temperature detecting means 112 detects at least a second set temperature not higher than the first set temperature, thereby reducing power consumption in defrosting. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a refrigerator with reduced power consumption during defrosting of an evaporator.

  In recent years, refrigerators have become more energy efficient from the viewpoint of protecting the global environment, and have attempted to reduce power consumption by increasing the efficiency of the refrigeration cycle using an inverter compressor and reducing the amount of heat entering the refrigerator body using vacuum insulation. Refrigerators are provided, and further energy savings are required.

  Conventionally, this type of refrigerator reduces the power consumption during defrosting by improving the energization method to the defrosting heater in order to further save energy (for example, refer to Patent Document 1).

  FIG. 5 shows a configuration of a conventional refrigerator described in Patent Document 1. As shown in FIG.

  As shown in FIG. 5, the refrigerator main body 100 is provided with a plurality of storage rooms (for example, a refrigeration room 10 in the upper stage, a vegetable room 11 in the middle stage, and a freezing room 12 in the lower stage). A compressor 1 and a cooler chamber 3 are provided on the back surface of the freezer compartment 12, and an evaporator 4, an internal fan 7, and a defrost heater 15 are provided in the cooler chamber 3. Further, ducts (for example, a refrigerator compartment duct 8 and a freezer compartment duct 9) for supplying cold air from the cooler compartment 3 to each storage compartment (the refrigerator compartment 10, the vegetable compartment 11, the freezer compartment 12, etc.) are provided. . In addition, a control board 16 is provided on the back of the refrigerator compartment 10, and performs compressor on / off control, damper open / close control, defrost heater 15 on / off control, and storage chamber temperature control.

  FIG. 6 is a control flowchart showing the operation during defrosting of the conventional refrigerator described in Patent Document 1.

  As shown in FIG. 6, the defrosting start determination is performed in the defrosting determination step ST101 depending on whether or not the time of the microcomputer timer has reached a predetermined time. The compressor is stopped in the machine stop step ST102, and energization to the defrost heater 9 is started in the defrost heater energization step ST103. Thereafter, when the temperature Te of the evaporator 7 is equal to or higher than the predetermined first set temperature T1 in the evaporator temperature determination step ST104, the energization to the defrost heater 9 is stopped in the defrost heater energization stop step ST105.

  Then, in the evaporator temperature determination second step ST106, the temperature of the evaporator 7 is determined, and it is determined whether or not the temperature Te of the evaporator 7 is equal to or higher than a predetermined second set temperature T2. When the temperature Te of the evaporator 7 is equal to or higher than the predetermined second set temperature T2, energization to the defrost heater 9 is started in the defrost heater energization step ST107.

  Further, the temperature of the evaporator 7 is determined in the third evaporator temperature determination step ST108, and it is determined whether or not the temperature Te of the evaporator 7 is equal to or higher than a predetermined third set temperature T3. When the temperature Te of the evaporator 7 is equal to or higher than the predetermined third set temperature T3, the defrosting heater 9 is deenergized in the defrosting heater energization stop step ST109, the defrosting control is completed, and the normal operation control step ST110 is performed. Shifts to normal operation control at.

Accordingly, the defrosting heater 9 is energized only at the beginning and the end at the time of defrosting, and the other (the time between the first energization and the last energization) is off cycle defrosting without energizing the defrosting heater. The total power consumption is reduced by reducing the total defrosting heater energization time.
JP 2005-37010 A

  However, in the above-described conventional configuration, the defrost heater is energized only at the beginning and the end at the time of defrosting, and the other (time between the first energization and the last energization) is off cycle defrost without energizing the defrost heater. Since the defrosting heater input at the beginning and end of the defrosting is constant, the temperature rise of each part of the evaporator is caused by the amount of heat more than necessary when the evaporator temperature rises at the end of the defrosting. When the temperature rises, the overshoot width increases after defrosting heaters are energized, and not only increases power consumption during defrosting, but also damages to foods due to temperature rise in each storage room, and cooling operation after defrosting ends. The time becomes longer and the power consumption during cooling operation also increases. In addition, the temperature of the peripheral parts of the cooling chamber is also rising at the end of the defrosting, and since the temperature rises more than necessary, deformation due to heat occurs, and a deformation preventing member such as an aluminum foil is required, leading to an increase in cost.

  Also, if the refrigerator doors are opened and closed many times in summer and high temperature and humidity, the evaporator may not be uniformly frosted, and uneven frost may occur, which may further increase the temperature rise variation and generate frost residue. was there.

  In addition, when using a flammable refrigerant as the refrigerant, the surface temperature of the defrost heater, which is a heating element, is important from the viewpoint of safety, and the capacity of the defrost heater is reduced in order to reduce the surface temperature due to an excessive temperature increase due to overshoot. Must be reduced, which increases the defrosting time.

  The present invention solves the above-described conventional problems, and reduces a power consumption during defrosting, can suppress food damage due to a temperature rise in each storage room, and is equipped with an inexpensive defrosting control. The purpose is to provide.

  In order to solve the above-described conventional problems, a refrigerator according to the present invention includes a heat insulating box, a refrigeration cycle provided at least in the heat insulating box, and a defrost heater that performs defrosting of the evaporator, When the evaporator temperature detecting means for detecting the temperature of the evaporator and the control means for controlling the defrosting are provided, the control means is configured such that the evaporator temperature detecting means is equal to or higher than a first set temperature. The defrosting is finished, and the output of the defrosting heater is reduced when the evaporator temperature detecting means becomes equal to or higher than the second set temperature not higher than the first set temperature.

  Moreover, the refrigerator of the present invention detects a temperature of the heat insulating box, a refrigeration cycle provided in the heat insulating box and provided with at least an evaporator, a defrost heater for defrosting the evaporator, and the temperature of the evaporator. It has an evaporator temperature detection means and a control means for controlling defrosting, and the control means ends the defrosting when the evaporator temperature detection means becomes a first set temperature or higher, The evaporator temperature detecting means has a second set temperature that is not more than the first set temperature, and the control means is from the start of defrosting until the evaporator temperature detecting means becomes not less than the second set temperature. The output of the defrosting heater is adjusted according to time.

  Thus, the temperature of the evaporator reaches 0 ° C. after the defrosting heater is energized at the time of defrosting, becomes constant for a while near 0 ° C., and then rises to 0 ° C. or more. By reducing the output to the defrosting heater until the end of the defrosting when the temperature starts to rise above 0 ° C, the overshoot of the temperature rise of the evaporator after the completion of the defrosting can be suppressed. Therefore, it is possible to prevent the temperature rise of the cooling chamber surrounding parts more than necessary, reduce the power consumption during defrosting, and prevent the temperature rise in the storage chamber.

  The refrigerator of the present invention can reduce power consumption at the time of defrosting without reducing the defrosting capacity of the evaporator, can suppress damage to foods and the like due to temperature rise in each storage room, and can perform defrost control at low cost. An on-board refrigerator can be provided.

  The invention according to claim 1 detects the temperature of the heat insulating box, the refrigeration cycle provided at least in the heat insulating box, the defrost heater for defrosting the evaporator, and the temperature of the evaporator. It has an evaporator temperature detection means and a control means for controlling defrosting, and the control means ends the defrosting when the evaporator temperature detection means becomes a first set temperature or higher, Since the output of the defrosting heater is reduced when the evaporator temperature detecting means becomes equal to or higher than the second set temperature that is lower than the first set temperature, the overshoot of the temperature rise of the evaporator is suppressed, and more than necessary. By preventing the temperature rise, the defrosting efficiency can be improved and the power consumption during defrosting can be reduced.

  Invention of Claim 2 detects the temperature of the heat insulation box body, the refrigerating cycle with which the heat insulation box body was equipped with at least the evaporator, the defrost heater which defrosts the evaporator, and the evaporator An evaporator temperature detecting means for controlling the defrosting, and a control means for controlling the defrosting, wherein the control means ends the defrosting when the evaporator temperature detecting means becomes a first set temperature or higher. The evaporator temperature detecting means has a second set temperature that is not more than the first set temperature, and the control means is from the start of defrosting until the evaporator temperature detecting means becomes not less than the second set temperature. Since the output of the defrosting heater is adjusted according to the time required, the temperature can be raised according to the amount of frost formation, overshooting of appropriate defrosting and evaporator temperature rise is suppressed, and an unnecessary temperature rise is prevented. To improve defrosting efficiency It is possible to reduce the power consumption during the defrosting.

  In addition to the invention described in claim 1 or 2, the control device according to claim 3 adjusts the output to the defrosting heater by increasing or decreasing the applied voltage, so fine control is possible. Thus, the amount of heat generated by the defrosting heater can be increased or decreased in accordance with the use environment conditions or the amount of frost formation, and the power consumption during defrosting can be reduced.

  In addition to the invention described in claim 1 or 2, the invention described in claim 4 intermittently applies a voltage to the defroster heater, so that the defroster is heated until the defrosting is finished after the second set temperature. Transformer is not required as a means to reduce the output of the battery, and it is possible to suppress the overshoot of the inexpensive and appropriate defrosting and the temperature rise of the evaporator, and the defrosting efficiency is improved by removing the temperature rise more than necessary. Power consumption during frost can be reduced.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein a flammable refrigerant is enclosed in the refrigeration cycle, and when the flammable refrigerant is used as the refrigerant, From the viewpoint of safety, the surface temperature of the defrosting heater, which is a heating element, is important. In order to reduce the surface temperature due to an excessive temperature increase due to overshoot, the capacity of the defrosting heater must be reduced. Even in the case where the time is long, by preventing the temperature from rising more than necessary, the defrosting efficiency can be improved and the power consumption during defrosting can be reduced.

(Embodiment 1)
FIG. 1 is a cross-sectional view of the refrigerator according to Embodiment 1 of the present invention. FIG. 2 is a temperature rise curve diagram of the evaporator according to Embodiment 1 of the present invention. FIG. 3 is a control flowchart during defrosting of the refrigerator in the first embodiment of the present invention.

  1, 2, and 3, the heat insulating box 101 is divided into a plurality of heat insulating sections, and has a configuration in which the upper part is a revolving door type and the lower part is a drawer type. From the top, there are a refrigerator compartment 102, a drawer-type vegetable compartment 104 and a drawer-type freezer compartment 103.

  The refrigeration cycle includes a compressor 105 at the lower back of the heat insulating box 101, a condenser 106 provided at the lower part of the heat insulating box 101, a capillary 107 as a decompressor, and a dryer (not shown) for removing water. And an evaporator 110 provided in the vicinity of a cooling fan 109 installed in the cooling chamber 108 on the back of the vegetable compartment 104 and the freezing compartment 103 is connected in a ring shape.

  In addition, a defrosting heater 111 that performs defrosting is provided below the evaporator 110, and a defrosting sensor 112, which is an evaporator temperature detecting means, is attached to the evaporator 110.

  Further, on the back surface of the heat insulating box 101, a control board 113 is provided for controlling the temperature of each storage room, the operation of the compressor 105, and the start and end of defrosting by the defrost sensor 112.

  Next, the control operation during defrosting and the temperature rise of the evaporator will be described. When the defrosting start determination is performed in the defrosting control start determination step ST121 depending on whether the time of the timer of the microcomputer mounted on the control board 113 has reached a predetermined time, etc. Stops the compressor 105 in the compressor stop step ST122 and starts energizing the defrost heater 111 in the defrost heater energization start step ST123. Thereafter, the temperature of the evaporator 110 is detected by the defrosting sensor 112 attached to the evaporator 110 and the control board 113 in the evaporator temperature determination step ST126, and the temperature Te of the evaporator 110 is set in advance. When the temperature is equal to or higher than T101 temperature, defrosting is terminated in defrosting heater energization stop step ST127, and cooling operation is started in normal control step ST128.

  Regarding the temperature behavior of the evaporator 110 during defrosting, the temperature Te of the evaporator 110 is about −30 ° C. before the start of defrosting, and gradually approaches 0 ° C. when the defrosting is started, and then about 0 Stable for a certain time around ℃ After maintaining about 0 ° C., the temperature starts to rise, and when the temperature reaches a preset temperature, for example, 10 ° C. or higher, the defrosting is finished. After completion of defrosting, the cooling operation is resumed through, for example, start-up control of the compressor 105, and the temperature Te of the evaporator 110 gradually reaches about −30 ° C. before the start of defrosting.

  In the above defrosting, when the temperature of the evaporator 110 becomes 0 ° C. or higher, the frost adhering to the evaporator 110 becomes water and is drained. In the conventional case, even after the temperature of the evaporator 110 reaches 0 ° C., the temperature of each part of the evaporator 110 is non-uniform due to the heat generated by the defrost heater 111 with a constant output. Since the degree of temperature rise is large compared to the upper part, the average temperature of the evaporator 110 at the end of defrosting is much larger than the T101 temperature at which defrosting ends. Further, even after the defrosting heater energization is stopped and the defrosting is finished, overshoot occurs due to residual heat, and the temperature of the evaporator 110 further increases.

  Here, a T102 temperature which is a second set temperature set below T101 which is a defrosting end temperature is provided, and the T102 temperature is set, for example, from 1 ° C to 5 ° C. In the defrosting heater energization start step ST123, the defrosting heater is set. When the temperature Te of the evaporator 110 is detected as T102 or higher in the evaporator temperature determination step ST124, the output from the control board 113 to the defrost heater 111 is reduced in the output reduction step ST125 to the defrost heater. Thereafter, when the temperature Te of the evaporator 110 becomes equal to or higher than the T101 temperature in the evaporator temperature determination step ST126, the defrosting is terminated in the defrosting heater energization stop step ST127, and the cooling operation is started in the normal control step ST128.

  As described above, after detecting the temperature equal to or higher than the set temperature T102 that is equal to or lower than the defrosting end temperature and equal to or higher than 0 ° C., the output to the defrosting heater 111 is reduced, and the evaporator 110 that is in a state in which frost is generally removed By suppressing the heat generation amount of the defrosting heater 111 in the process of increasing the temperature, the average temperature of the evaporator 110 can be made uniform, and overshoot due to residual heat after the defrosting heater energization is stopped and the defrosting is completed can be suppressed. Therefore, although the amount of heat necessary for defrosting can be suppressed and the defrosting time due to the reduction in output is extended, the power consumption required for defrosting can be reduced. Furthermore, since the amount of generated heat can be reduced, the cooling operation time after the completion of the defrosting can also be reduced, and the power consumption reduction effect can be exhibited during both the defrosting and the cooling operation.

  In addition, by reducing overshoot due to residual heat, not only the food in each storage room is damaged, but also the surrounding parts in the cooling chamber 108 rise in temperature at the end of the defrosting, and deformation is usually prevented by aluminum foil etc. However, since such deformation preventing members can be reduced, the cooling chamber can be configured at low cost.

  Moreover, when using a combustible refrigerant | coolant as a refrigerant | coolant, the surface temperature of the defrost heater which is important from a safety | security side can be reduced.

  In addition, a relatively large output is given to the heater at the initial stage of defrosting, and the output of the heater 111 is lowered by the detection of the evaporator temperature detecting means set so that the temperature of the heater 111 is equal to or lower than a predetermined temperature. The safety of the functional refrigerant can be improved, and the heating rate at the initial stage of defrosting can be increased to shorten the defrosting time, thereby realizing higher efficiency.

  In addition, if a heater with a glass tube covered in order to improve the safety of the heater 111 is used, the surface temperature of the heater can be reduced and the amount of heat capacity increased around the glass tube can be reduced during defrosting. It is possible to improve the temperature rise.

  In addition, as a means for improving the safety of the heater, a similar effect can be expected with a glass tube wrapped with an aluminum fin or a tube abutted against the pipe.

  In addition, since the output to the defrost heater 111 can be reduced as well as the output to the defrosting heater 111 can be increased when the transformer is used as the output lowering means, for example, when the ambient temperature decreases, the defrosting time becomes longer and each storage Although there is concern about damage to the food in the room, when the ambient temperature decreases, the output can be increased to shorten the defrosting time, and damage to the food in each storage room can be suppressed.

  Moreover, since the output voltage can be changed linearly when the transformer is used, it is possible to energize a stable defrost heater.

  When a relay such as a mechanical relay is used as the output reduction means, the output to the defrosting heater 111 can be reduced by turning it on / off by time control. A device can be configured.

(Embodiment 2)
FIG. 4 is a control flowchart at the time of defrosting the refrigerator in the second embodiment of the present invention. In addition, about the same structure as Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In FIG. 4, when the defrosting start determination is performed in the defrosting control start determination step ST <b> 221 depending on whether or not the timer of the microcomputer mounted on the control board 113 has reached a predetermined time, the defrosting is started. If it is determined, the compressor 105 is stopped in the compressor stop step ST222, and energization of the defrost heater 111 is started in the defrost heater energization start step ST223. Here, a T202 temperature which is a second set temperature set below T201 which is a defrosting end temperature is provided, and the T202 temperature is set to, for example, 1 ° C. to 5 ° C., and the defrost heater is set in the defrost heater energization start step ST223. When the temperature Te of the evaporator 110 is detected to be T2 or more in the evaporator temperature determination step ST224, the power supply to the defrost heater 111 in the defrost heater energization start step ST223 is detected in the T202 temperature required time t1 detection step ST225. Is detected in the evaporator temperature determination step ST224 until the temperature Te of the evaporator 110 is detected as T202 or more, and the output to the defrost heater is increased or decreased in step ST226. Increase or decrease the output. Thereafter, in evaporator temperature determination step ST227, the temperature of evaporator 110 is detected by defrost sensor 112 attached to evaporator 110 and control board 113, and temperature Te of evaporator 110 is set in advance. When the temperature is equal to or higher than T201 temperature, defrosting is terminated in defrosting heater energization stop step ST228, and cooling operation is started in normal control step ST229.

  As described above, after detecting the set temperature T202 that is equal to or lower than the defrosting end temperature and equal to or higher than 0 ° C., the frosting amount of the evaporator 110 is determined by the energization time t1 to the defrosting heater 111 from the start of the defrosting. By predicting, for example, when it becomes longer than a preset time due to the combination of the ambient temperature and t1 time, the microcomputer of the control board 113 determines that the amount of frost formation is large, and by increasing or decreasing the output to the defrost heater 111 Appropriate defrosting can be performed, and at the same time, the overshoot of the temperature rise of the evaporator 110 can be suppressed and the power consumption during defrosting can be reduced.

  As mentioned above, the refrigerator concerning this invention can provide the refrigerator which reduced the power consumption at the time of defrosting of an evaporator, and can be applied also to cooling devices other than a refrigerator.

Sectional drawing of the refrigerator in Embodiment 1 of this invention Temperature rise curve diagram of the evaporator in Embodiment 1 of the present invention Control flowchart at the time of defrosting of the refrigerator in Embodiment 1 of the present invention Control flowchart at the time of defrosting of the refrigerator in Embodiment 2 of the present invention Cross-sectional view of a conventional refrigerator Control flowchart during defrosting of conventional refrigerator

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Heat insulation box 105 Compressor 106 Condenser 107 Decompressor 110 Evaporator 111 Defrost heater 112 Defrost sensor (Evaporator temperature detection means)
113 Control board (control means)

Claims (5)

  A heat insulation box, a refrigeration cycle provided in the heat insulation box and provided with at least an evaporator, a defrost heater for defrosting the evaporator, an evaporator temperature detecting means for detecting the temperature of the evaporator, and a defrost The control means terminates the defrosting when the evaporator temperature detecting means reaches a first set temperature or higher, and the evaporator temperature detecting means The refrigerator which reduces the output of the said defrost heater when it becomes more than 2nd preset temperature below 1 preset temperature.   A heat insulation box, a refrigeration cycle provided in the heat insulation box and provided with at least an evaporator, a defrosting heater for defrosting the evaporator, an evaporator temperature detecting means for detecting the temperature of the evaporator, Control means for controlling frost, wherein the control means terminates defrosting when the evaporator temperature detection means reaches or exceeds a first set temperature, and the evaporator temperature detection means The control means has a second set temperature that is equal to or lower than the first set temperature, and the control means outputs the output of the defrost heater according to the time from the start of defrosting until the evaporator temperature detection means becomes equal to or higher than the second set temperature. Refrigerator to adjust.   The refrigerator according to claim 1 or 2, wherein the control means adjusts the output of the defrosting heater by increasing or decreasing the applied voltage.   The refrigerator according to claim 1 or 2, wherein the control means intermittently applies a voltage to the defrost heater.   The refrigerator according to any one of claims 1 to 4, wherein a flammable refrigerant is enclosed in the refrigeration cycle.

Images