KR100493692B1 - The defrost heater of using refrigerator - Google Patents

Abstract

The present invention relates to a defrost heater for a refrigerator, which smoothly removes frost formed on an evaporator through an induction heating method of directly heating the evaporator by applying a high frequency current to a heated object surrounded by a heating coil, that is, an evaporator. Etc., there is an excellent effect of improving the defrosting efficiency and heat transfer performance of the entire evaporator according to the uniform heat supply to each of the evaporator.

In addition, when the temperature detector for detecting the surface temperature of the evaporator and the frequency controller for controlling the frequency of the applied power supply is installed on the evaporator, the defrost heater according to the amount of frost formed on the evaporator through the temperature detector and the frequency controller There is also an excellent effect of improving the defrosting speed to remove the frost formed on the evaporator by varying the heating capacity of the.

Description

Defrost heater of using refrigerator

The present invention relates to a refrigerator, and more particularly, to smoothly remove frost formed on an evaporator through an induction heating method of directly heating the evaporator by applying a high frequency current to a heated object surrounded by a heating coil, that is, an evaporator. It relates to a defrost heater for a refrigerator.

In general, the refrigerator discharges cold air generated by a refrigeration cycle composed of a compressor, a condenser, an expansion valve, an evaporator, and lowers the temperature in the refrigerator to freeze or refrigerate food and the like. As shown in FIG. 1, the main body 100, a freezing chamber 110 and a refrigerating chamber 120 for freezing and refrigerating loads (food) by dividing up and down inside the main body 100, and the main body 100. The refrigerator compartment door 130 and the refrigerator compartment door 140, which are mounted at one side of the refrigerator, to open and close the freezer compartment 110 and the refrigerating compartment 120, and cold air necessary for cooling the freezer compartment 110 and the refrigerating compartment 120 may be generated. It consists of a refrigeration cycle equipment consisting of a compressor 150 and a condenser (not shown), an expansion valve (not shown), and an evaporator 160 forming a refrigeration cycle.

In addition, the cold air generated through the evaporator 160 to take the ambient heat of the elements of the refrigeration cycle equipment to evaporate the refrigerant in the gas phase state to each shelf 170 of the freezer compartment 110 and the refrigerating compartment 120. Cold air discharge ports 190 and 190a are formed in the inner wall 180 of the rear surface of the freezing chamber 110 and the refrigerating chamber 120 to be discharged.

In the refrigerator configured as described above, the refrigerant, which is phase-changed in a low temperature low pressure gas phase by the evaporator 160, flows to the compressor 150 and is compressed from the low temperature low pressure to the high temperature high pressure through the compressor 150, and the compressed high temperature high pressure The gas phase refrigerant is cooled and condensed in the course of passing through the condenser, and is phase-changed to a high-pressure liquid state. The refrigerant, which has been phase-changed into a high-pressure liquid state, is easily evaporated by heat exchange in the evaporator 160 while passing through an expansion valve. After decompression (heat expansion), the refrigerant flows to the evaporator 160 where the evaporation process is performed. As described above, the refrigerant introduced into the evaporator 160 absorbs heat inside the refrigerator and absorbs heat inside the refrigerator. After the phase change to the state to cool the air around it, it forms a refrigeration cycle flowing back into the compressor 150.

At this time, the air (chill) cooled while the heat is lost to the refrigerant through heat exchange with the evaporator 160 is driven by the blower fan 200 installed on the evaporator 160, the freezing chamber 110 and the refrigerating chamber 120. The temperature of the freezing compartment 110 and the refrigerating compartment 120 is lowered as the discharge air is circulated through the cold air discharge ports 190 and 190a formed in the rear inner wall 180.

On the other hand, in the case of the evaporator 160 to take the heat of the ambient air to evaporate the refrigerant in a gaseous state, as shown in Figure 2, the plurality of tubes 161 and the tube 161 through which the refrigerant flows A plurality of pins 162 fixed to a surface of the at a predetermined interval, a tube bracket 163 fixed to both ends of the tube 161 to prevent flow of the tube 161, and the tube bracket 163 It is installed on the front / rear side and consists of a defrost heater 164 for defrosting the frost formed on the tube 161 and the fin 162 by the temperature difference between the cold and the refrigerant circulated in the re-flow. In particular, in the case of the defrost heater 164, the siege heater (see Fig. 2a) is installed on the bottom of the evaporator 160, or the surface of the refrigerator of the Republic of Korea Utility Model Publication No. 1999-36171 published on September 15, 1999 Like a heater, a tube bracket 3 that is a component of the evaporator 360 A planar heater 365 (see FIG. 2B) is installed on the front and rear surfaces of the evaporator 360 at predetermined intervals through fixing means 364 formed by bending both edges of the 63. Reference numeral 367 denotes a heat generating surface 367 of the planar heater 365, and 368 is a heat insulating surface 368 of the planar heater 365.

At this time, in the case of the sheath heater 164 or the planar heater 365 which is used as a heat source for the defrosting function of the conventional evaporator 160, 360, the fin 162 of the evaporator 160, 360 frost is implanted. Space between the heaters 164 and 365 and the tubes 161 and 361 and the heaters 164 and 365 which are heat sources. The method performs a defrost function to remove frost formed on the evaporators 160 and 360 through a heat transfer method such as convection.

However, the defrosting method is very different from the heat transfer efficiency and the effect by the type of heater 164, 365 or the installation method, and the like, in particular with a portion adjacent to the heater 164, 365 as a heat supply source There is a limit to uniformly apply the heater heat in the distant part, there was a big problem that the temperature of the heater 164, 365 must be raised above a certain level in order to sufficiently heat the heater to the portion where the heat transfer is weak. .

In addition, as described above, there is a limit that the heater heat is uniformly applied to the entire evaporator 160, 360, and thus the defrost function of the entire evaporator 160, 360 is significantly reduced, and the defrost function is lowered. Defrosting efficiency and heat transfer performance of the evaporator (160,360) due to the large problem was also greatly reduced.

In addition, as described above, the defrost heaters 164 and 365 are spaced apart from the lower end of the evaporators 160 and 360 or the front / rear side, so that the heat generated from the defrost heaters 164 and 365 is increased. Along with the disadvantage that the defrosting time takes a very long time to act to the center of the evaporator 160, 360, there is a big problem that the power consumption of the refrigerator also increases as the defrosting time becomes longer.

The present invention devised to solve the above problems, the frost formed on the evaporator smoothly through the induction heating method of directly heating the evaporator by applying a high frequency current on the heated object, that is, the evaporator surrounded by the heating coil. The purpose of the present invention is to improve the defrosting efficiency and heat transfer performance of the entire evaporator according to the uniform heat supply to each part of the evaporator.

In addition, since the induction heating method is used to remove the frost formed on the evaporator while supplying a uniform amount of heat to each part of the evaporator, the efficient defrosting operation is performed compared to the defrost heater installed on the bottom or front / rear of the conventional evaporator. Accordingly, there is another purpose to greatly reduce the power consumption of the refrigerator.

And, when the temperature detector for detecting the surface temperature of the evaporator and the frequency controller for controlling the frequency of the applied power supply on the evaporator, the defrost heater according to the amount of frost formed on the evaporator through the temperature detector and the frequency controller Another object is to improve the defrosting speed of removing frost formed on the evaporator by varying the heating capacity of the.

The object of the present invention is a heating coil wrapping the circumference of the evaporator, a high frequency generator for converting the frequency of the power supplied (applied) to the heating coil to be supplied as a high frequency current, and supplied to the heating coil through the high frequency generator Can be solved by the defrost heater of the present invention consisting of a metal member installed in a predetermined position of the evaporator so that the induction heating method for heating the evaporator directly using the high frequency current, see the accompanying drawings This will be described in detail.

Figure 3 shows a schematic perspective view of the evaporator to which the present invention is applied, Figure 4 shows a perspective view and a detailed view of the defrost heater according to the present invention.

The defrost heater for a refrigerator of the present invention includes a defrost heater for removing frost formed on the evaporator 460;

A plurality of winding coils wound around the evaporator 460;

A high frequency generator 480 for converting a frequency of a power supply (applied) to the heating coil 470 into a high frequency current to supply the heating coil 470;

The evaporator 460 such that an induction heating method for directly heating the evaporator 460 using the heat energy is performed by converting electrical energy into thermal energy by the eddy current generated while the high frequency current supplied to the heating coil 470 is applied. And a metal member 490 provided at a predetermined position.

Hereinafter, the defrost heater for a refrigerator of the present invention will be described in detail.

The defrost heater for a refrigerator of the present invention is an evaporator 460 through an induction heating method for directly heating the evaporator 460 by applying a high frequency current to the heated object surrounded by the heating coil 470, that is, the evaporator 460. In order to improve the defrosting efficiency and heat transfer performance of the entire evaporator 460 according to the uniform heat supply to each part of the evaporator 460, such as to remove frost formed on the phase smoothly, the circumference of the evaporator 460 A heating coil 470 wound around a large number, a high frequency generator 480 for converting a frequency of a power source into a high frequency to be supplied to the heating coil 470, and a heating coil 470 through the high frequency generator 480. As the defrost heater is configured by the metal member 490 which directly heats the evaporator 460 using the supplied high frequency current, the present invention will be described in detail. The same reference numerals will be applied to the same configurations as those of the present invention and the conventional art described above.

In the case of the evaporator 460 according to the present invention, a fin-tube type evaporator 160 or 360 having the same configuration as the conventional evaporator shown in FIGS. 2A and 2B, or the applicant filed March 19, 2003 The evaporator of the type (Application No. 2003-17167) and the like can be selectively applied and used, in particular, in the present invention, instead of the applicant's pre- filed evaporator structure, the conventional fin-tube type evaporator was applied.

The defrost heater of the present invention installed in the fin-tube evaporator 460 and configured to remove frost formed on the evaporator 460 through induction heating, as shown in FIGS. 3 and 4. A heating coil wound around the circumference of the evaporator 460 and 470; A high frequency generator 480 for converting a frequency of a power supply (applied) to the heating coil 470 into a high frequency current to supply the heating coil 470; The evaporator 460 such that an induction heating method for directly heating the evaporator 460 using the heat energy is performed by converting electrical energy into thermal energy by the eddy current generated while the high frequency current supplied to the heating coil 470 is applied. And a metal member 490 provided at a predetermined position.

At this time, the metal member 490 is made of an iron material so that the induction heating can be performed smoothly, and in particular, the fin surface of the evaporator 460, or the outer peripheral surface of the tube 461 like the fins are provided at predetermined intervals. .

Further, the metal member 490 may be provided on the surface of the fin 462 of the evaporator 460 described above or on the outer circumferential surface of the tube 461 like the fin 462. Note that it may be installed in the tube bracket 463 fixed to both ends of the tube 461 to secure the 461.

Referring to the induction heating method of the present invention in more detail as follows.

Figure 5 shows the principle of induction heating according to the present invention, Figure 6 shows a hysteresis loop according to the induction heating of the present invention.

In the flow heating method according to the present invention, as shown in FIG. 5, conductors such as metals located in a coil in which an alternating current (high frequency) current flows include eddy current loss (EDDY CURRENT LOSS) and hysteresis loss (HYSTERESIS LOSS). Heat is generated, and heating the material to be heated using this heat is called induction heating, and in particular, using high frequency current is called high frequency induction heating.

At this time, the eddy current loss (EDDY CURRENT LOSS) is the alternating magnetic flux according to the alternating current is generated in the coil through which the alternating current (high frequency) current (i1) flows, as shown in Figure 5, the induced current (induction electromotive force) : This occurs. In particular, a current generated by the electromotive force is called an eddy current, and when the eddy current flows in a conductor having an arbitrary resistance, that is, a heated member, JOUL heat is generated in the conductor. This is called eddy current loss, or eddy current loss, and becomes the main heating source during induction heating. The eddy current described above is "heat is generated when current flows through a conductor with resistance, and the amount of heat is proportional to the square of the current flowing and the resistance of the conductor and the time the current flows." In terms of Joule's Law,

We = ne f ² Bm ²

ne: constant

f: frequency

Bm: magnetic flux density

As shown in the implantation, the eddy current loss is proportional to the square of the frequency, so it is affected by the frequency more than the hysteresis loss. As described above, the hysteresis loss is effective when the frequency is low, and the eddy current loss mainly when the frequency is higher than 100 khz. Will be heated.

In addition, the hysteresis loss (HYSTERESIS LOSS) is a magnetic material, when the heating coil is wound around the magnetic material and applying an alternating current, the magnetic material is magnetized, when the magnetic field strength is gradually increased, the magnetic flux density (B) The curve representing the change of and the curve representing the strength of the magnetic field (H) do not coincide and form an annular curve as shown in FIG. 6, which is called a hysteresis phenomenon. The curve is called a hysteresis loop.

In particular, the larger the area enclosed by the hysterical loop, the greater the hysteresis loss. However, the higher the induction heating, the higher the heating efficiency.

Wh = nh f Bm ^1.6 (wb / ㎡)

nh: hysteresis constant according to the type of iron core

f: frequency used

Bm: Primary magnetic flux density (wb / m2)

However, when the use frequency is relatively high above 50 KHz, the eddy current loss proportional to the square of the frequency is much larger, so this loss is relatively small and is neglected when the frequency is considerably high. Of course, in the case of a nonmagnetic material or a magnetic material such as copper or aluminum, if the temperature is raised above the magnetic transformation point, the hysteresis loss is eliminated, and from then on, only the eddy current is heated.

Referring to the defrost process to remove the frost formed on the evaporator through the defrost heater of the present invention configured as described above are as follows.

Figure 7 is a state diagram showing the heat conduction characteristics that the frost formed on the evaporator by the defrost heater of the present invention is removed.

The tube 461 of the evaporator 460 by the temperature difference between the coolant flowing through the freezer compartment 110 and the refrigerating chamber 120 to the evaporator and the refrigerant flowing inside the tube 461 of the evaporator 460 and When frost is formed on the fin 462, the refrigeration cycle operation during the operation is stopped, and power is supplied to the heating coil 470 wound around the evaporator 460, where the power is the evaporator. 460, before being supplied to the heating coil 470 surrounding the periphery, the frequency of the power source is converted into a high frequency current through the high frequency generator 480 connected to the heating coil 470, and then the heating coil ( 470 is supplied to the high-frequency current flows through the heating coil 470.

When a high frequency current flows through the heating coil 470 as described above, the plurality of fins 462, which are elements of the evaporator 460, that is, the evaporator may be formed in a conductor state in which induced electromotive force may be generated while the high frequency current flows. The metal member 490 is attached to the surface of the fin 462 of the 460, or a high frequency current is applied to the plurality of fins 462 having the fin 462 as the metal member 490 through the heating coil 470. As it flows, eddy currents are generated by induced electromotive force, and electrical energy is converted into thermal energy while the generated eddy currents flow through a plurality of fins 462, which are conductors having an arbitrary resistance, that is, to be heated. The defrost function of removing frost formed on the evaporator 460 is performed through an induction heating method (see FIG. 5) in which JOUL heat is generated on the plurality of fins 462.

In particular, since the metal member 490 formed on the surface of the fin 462 of the evaporator 460 or the fin 462 itself serves as a heat source for the defrosting function, the evaporator 460 is provided through the metal member 490. The characteristic that can supply a uniform amount of heat to the whole is generated.

In particular, in the case of the defrosting operation as described above, the defrosting heater is installed in the evaporator 460 so that the defrosting operation is safely performed without giving an explosion risk to the refrigerant flowing in the tube 461 of the evaporator 460. do.

FIG. 8 shows another embodiment of the defrost heater according to the present invention, which includes a plurality of winding coils 470 wound around the evaporator 460 as shown in FIG. 8; A temperature sensor 475 installed at a predetermined position of the evaporator 460 to sense a surface temperature of the evaporator 460; A temperature detector 476 for detecting a surface temperature of the evaporator 460 sensed by the temperature sensor 475; A frequency controller 477 for controlling the frequency of the applied power according to the surface temperature of the evaporator 460 detected by the temperature detector 476; A high frequency generator 480 for converting the frequency of the power controlled by the frequency controller 477 into a high frequency current and supplying the heating coil 470; The evaporator 460 such that an induction heating method for directly heating the evaporator 460 using the heat energy is performed by converting electrical energy into thermal energy by the eddy current generated while the high frequency current supplied to the heating coil 470 is applied. And a metal member 490 provided at a predetermined position.

In addition, in the case of the metal member 490, as in the defrost heater of the present invention shown in Figs. 3 and 4, the surface of the fin 462 of the evaporator 460, or the tube 461 as the fin 462. Note that it may be installed on the outer peripheral surface, or on the tube bracket 463 fixed to both ends of the tube 461 to fix the tube 461, which is an evaporator 460 element.

In addition, in the case of the frequency controller 477, the frequency of the power supply is calculated according to the amount of frost by calculating the amount of frost formed on the evaporator 460 according to the surface temperature of the evaporator 460 detected by the temperature detector 476. To control.

As such, when the temperature detector 476 for detecting the surface temperature of the evaporator 460 and the frequency controller 477 for controlling the frequency of the applied power are installed on the evaporator 460, the temperature detector 476 and the frequency are provided. According to the amount of frost implanted on the evaporator 460 through the controller 477, the heating capacity of the defrost heater may be changed to improve the defrosting rate of removing frost formed on the evaporator 460.

The evaporator structure configured as described above is not only a top-type refrigerator applied as an embodiment of the present invention but also a bottom-type refrigerator in which a refrigerating compartment is located at the top and a freezer compartment is at the bottom. Note that the freezer compartment and the refrigerating compartment can also be applied to side by side-type refrigerators located on the left and right sides of the main body.

The defrost heater for a refrigerator of the present invention smoothly removes frost formed on the evaporator through an induction heating method in which a high frequency current is applied to a heated object surrounded by a heating coil, that is, an evaporator to directly heat the evaporator. There is an excellent effect to improve the defrosting efficiency and heat transfer performance of the entire evaporator according to the uniform heat supply to each part of the evaporator.

In addition, since the induction heating method is used to remove the frost formed on the evaporator while supplying a uniform amount of heat to each part of the evaporator, the efficient defrosting operation is performed compared to the defrost heater installed on the bottom or front / rear of the conventional evaporator. Accordingly, there is also an excellent effect that can significantly reduce the power consumption of the refrigerator.

And, when the temperature detector for detecting the surface temperature of the evaporator and the frequency controller for controlling the frequency of the applied power supply on the evaporator, the defrost heater according to the amount of frost formed on the evaporator through the temperature detector and the frequency controller There is also an excellent effect of improving the defrosting speed to remove the frost formed on the evaporator by varying the heating capacity of the.

1 is a schematic cross-sectional view of a typical refrigerator.

Figure 2a is a schematic perspective view of the sheath heater is installed on the bottom of the conventional evaporator.

Figure 2b is a schematic perspective view of the surface heater is installed on the front and rear of the conventional evaporator.

3 is a schematic perspective view of an evaporator to which the present invention is applied.

4 is a perspective view and a detailed view of the defrost heater according to the invention.

5 is a state diagram showing the principle of induction heating according to the present invention.

Figure 6 is a state diagram showing a hysteresis loop according to the induction heating of the present invention.

Figure 7 is a state diagram showing the thermal conductivity of the frost formed on the evaporator by the defrost heater of the present invention is removed.

8 is another embodiment of a defrost heater according to the present invention.

Explanation of symbols on main parts of drawing

160, 360, 460. Evaporators 161, 361, 461. Tubes

162, 362, 462. Pins 163, 363, 463. Tube bracket

164, 365. Defrost heaters 364. Fixing means

470. Heating coil 475. Temperature sensor

476. Temperature detector 477. Frequency controller

480. High frequency generator 490. Metal member

Claims (5)

A defrost heater for removing frost formed on an evaporator; A plurality of winding coils wound around the evaporator; A high frequency generator for converting the frequency of the power supplied to the heating coil into a high frequency current and supplying the heating coil to the heating coil; A metal member installed at a predetermined position of the evaporator so that an induction heating method of converting electrical energy into thermal energy and directly heating the evaporator using the thermal energy may be performed by the eddy current generated by the high frequency current supplied to the heating coil. Defrost heater for refrigerator, characterized in that configured. A defrost heater for removing frost formed on an evaporator; A plurality of winding coils wound around the evaporator; A temperature sensor installed at a predetermined position of the evaporator and sensing a surface temperature of the evaporator; A temperature detector for detecting a surface temperature of the evaporator sensed by the temperature sensor; A frequency controller for controlling the frequency of the applied power according to the surface temperature of the evaporator detected through the temperature detector; A high frequency generator for converting a frequency of the power controlled by the frequency controller into a high frequency current and supplying the heating coil; A metal member installed at a predetermined position of the evaporator so that an induction heating method of converting electrical energy into thermal energy and directly heating the evaporator using the thermal energy may be performed by the eddy current generated by the high frequency current supplied to the heating coil. Defrost heater for refrigerator, characterized in that configured. The defrost heater according to claim 1 or 2, wherein the metal member is provided on a fin surface of the evaporator or on an outer circumferential surface of the tube like the fin. 3. The defrost heater according to claim 1 or 2, wherein the metal member is installed on a tube bracket fixed to both ends of the tube to fix the tube, which is an evaporator element. The method of claim 2, wherein the frequency controller calculates the amount of frost formed on the evaporator according to the surface temperature of the evaporator detected by the temperature detector to control the frequency of the power supply according to the amount of frost defrost for refrigerators heater.