JP2017026210A - refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a heating amount from dew condensation prevention piping, a high temperature refrigerant-inflow amount to an evaporator and evaporation pressure to provide a refrigerator with high-energy-saving performance.SOLUTION: In the refrigerator including a refrigerant flow passage for causing a refrigerant discharged from a discharge port of a compressor 24 to flow to heat radiation means 41, the dew condensation prevention piping 43, decompression means 44, the evaporator 7 and a suction port of the compressor 24 in this order, temperature of an opening edge of the refrigerator is controlled by changing a throttle amount of the decompression means 44.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a refrigerator.

As a background art in this technical field, there is, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2015-14373).
In the summary column of Patent Document 1, “the dew condensation prevention pipe 43 that heats the opening edge of the heat box 10 is provided, and the refrigerant discharged from the discharge port of the compressor 24 is replaced with the heat radiation means 41, 42, the dew condensation prevention pipe 43. , The first refrigerant flow path A flowing in the order of the decompression means 44, the evaporator 7, and the suction port of the compressor 24, and the refrigerant discharged from the discharge port of the compressor 24, the heat radiation means 41, 42, the decompression means 44, An evaporator 7 and a second refrigerant flow path B that flows in the order of the suction port of the compressor 24, between the heat radiation means 41, 42 and the dew condensation prevention pipe 43, and between the dew condensation prevention pipe 43 and the evaporator 7. The refrigerant flow path control means 110, 100, and the refrigerant flow path control means 110, 100 switch the first refrigerant flow path A and the second refrigerant flow path B, change the throttle of the decompression means 44, and The refrigerant flow between the dew condensation prevention pipe 43 and the evaporator 7 is switched between communication and blockage. . "And there is a description.

Japanese Patent Laying-Open No. 2015-14373

  Generally, since the temperature of the door opening of a household refrigerator tends to decrease, there is a case where condensation is prevented by burying a dew condensation prevention pipe and flowing a high-temperature refrigerant into the pipe. When the evaporation pressure is controlled, the refrigerant flow rate also changes. Therefore, when the evaporation pressure changes, the flow rate of the high-temperature refrigerant flowing in the dew condensation prevention pipe and the amount of heat given to the opening are also affected. Therefore, when this dew condensation prevention pipe is used, it is necessary to consider that the amount of heating is insufficient due to a change in the evaporation pressure and that dew condensation does not occur.

  Patent Document 1 describes the content of controlling the pressure reduction amount according to the operation mode, but does not take into account the evaporation pressure change related to frost formation.

  Therefore, an object of the present invention is to provide a refrigerator with high energy saving performance by performing control in consideration of the inflow amount of high-temperature refrigerant, the evaporation pressure, and the frost formation amount of the evaporator.

The present invention has been made to solve the above-described problems.
That is, a heat insulating box having an opening edge that forms an opening in the front, a door that opens and closes the opening, a storage chamber formed by the door and the heat insulating box, a compressor, and a discharge port of the compressor In the refrigerator provided with a refrigerant flow path for flowing the refrigerant discharged from the heat dissipation means, the dew condensation prevention pipe, the decompression means, the evaporator, and the suction port of the compressor in the order, the opening by changing the throttle amount of the decompression means Control edge temperature.

It is a front view of the refrigerator regarding the Example of this invention. It is AA sectional drawing of FIG. It is a figure explaining the structure of the refrigerating cycle (refrigerant flow path) regarding the Example of this invention. It is a schematic diagram at the time of seeing the inside of the machine room regarding the Example of this invention from the back. It is a figure which shows the arrangement | positioning position of the wall surface heat radiating piping and the dew condensation prevention piping regarding the Example of this invention. It is a cross-sectional enlarged view of the freezer compartment partition wall regarding the Example of this invention. It is a cross-sectional schematic diagram which shows the outline of the heat exchange part regarding the Example of this invention. It is the figure which showed the state of the refrigerant | coolant in each part of the refrigerating cycle regarding the Example of this invention on the Mollier diagram. It is the figure which showed the state of the refrigerant | coolant inside piping from the compressor regarding the Example of this invention to a capillary tube. It is the figure which showed the state of the refrigerant | coolant when the evaporation pressure regarding the Example of this invention fell on the Mollier diagram. It is the figure which showed the switching conditions of the refrigerant flow path in the Example of this invention.

  The present invention includes a heat insulating box having an opening edge that forms an opening in the front, a door that opens and closes the opening, a storage chamber formed by the door and the heat insulating box, a compressor, and a compressor, In the refrigerator provided with the refrigerant flow path for flowing the refrigerant discharged from the discharge port in the order of the heat radiating means, the dew condensation prevention pipe, the pressure reducing means, the evaporator, and the suction port of the compressor, by changing the throttle amount of the pressure reducing means The temperature of the opening edge is controlled.

  A door opening / closing sensor that detects the opening / closing state of the door; and a timer that measures an elapsed time from a certain time; a value obtained by multiplying the opening time of the door by a coefficient; and a rotational speed of the compressor. When the sum of the product of the corresponding coefficient and the elapsed time and the value obtained by integrating from the end of defrosting reaches the specified value, the amount of restriction by the decompression means is decreased.

  A temperature sensor that measures the temperature around the refrigerator; and a temperature sensor that measures the temperature at the opening edge, and the temperature at the opening edge is predicted from the temperature around the refrigerator. If lower, the amount of restriction by the pressure reducing means is decreased.

  In addition, a humidity sensor for measuring the humidity of the opening edge is provided, and when the humidity of the opening edge becomes a certain level or more, the amount of restriction by the pressure reducing means is reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front view of a refrigerator according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. The refrigerator 1 of an Example is equipped with the refrigerator compartment 2, the ice making room 3, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6 from the upper direction as a storage room. The ice making chamber 3 and the upper freezing chamber 4 are arranged on the left and right. Note that the ice making chamber 3, the upper freezing chamber 4, and the lower freezing chamber 5 are in the freezing temperature zone and may be collectively referred to as the freezing chamber 60. The refrigerating room 2 is provided with doors 2a and 2b that are separated from each other on the front side, and the ice making room 3, the upper freezing room 4, the lower freezing room 5, and the vegetable room 6 are each a drawer type ice making. The room door 3a, the upper freezer compartment door 4a, the lower freezer compartment door 5a, and the vegetable compartment door 6a are provided.

  The refrigerator 1 includes a door sensor (not shown) that detects the open / closed state, a temperature setting device (not shown) that sets the temperature of the refrigerator compartment 2 and the vegetable compartment 6, and the temperature of the freezer compartment 60, and the like. Yes. A door hinge (not shown) that is fixed to the refrigerator 1 is provided in the upper part of the main body of the refrigerator 1 so that the refrigerator compartment doors 2 a and 2 b can be rotated, and the door hinge is covered with a door hinge cover 39. . Inside the door hinge cover 39, an outside air temperature sensor 37 and an outside air humidity sensor 38 for detecting the temperature and humidity outside the storage room are provided.

  The storage room and the outside of the storage room of the refrigerator 1 are separated by a heat insulating box 10 formed by filling a foam heat insulating material of urethane foam, for example, between the outer box 1a and the inner box 1b. Note that the evaporator storage chamber 8 communicating with the storage chamber is also separated from the outside by a heat insulating box 10. A vacuum heat insulating material 26 is mounted inside the heat insulating box 10 of the refrigerator 1.

  In each storage room of the refrigerator 1, the refrigerator compartment 2 and the freezer compartment 60 are separated by the refrigerator compartment-freezer compartment partition wall 28, and the freezer compartment 60 and the vegetable compartment 6 are separated by the refrigerator compartment-vegetable compartment partition wall 29. It has been. There is no partition that separates the storage chambers of the ice making chamber 3, the upper freezing chamber 4, and the lower freezing chamber 5, but leakage of the air in the freezing chamber 60 from the gaps of the doors 3a, 4a, and 5a to the outside of the storage chamber. A freezer compartment partition wall 30 to prevent is provided. The opening edge of the freezer compartment 60 formed by these partition walls 28, 29 and 30 and the doors 3a, 4a and 5a separate the freezer compartment 60 from the outside of the storage compartment.

  The refrigerator compartment 2 includes a plurality of door pockets 32 provided on the storage compartment side of the doors 2a and 2b and a plurality of shelves 40 that divide the refrigerator compartment 2 into a plurality of storage spaces. In the lower part of the refrigerator compartment 2, there is provided a reduced-pressure storage chamber 20 that enhances the storability of food by reducing the pressure inside.

  The upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6 are provided with storage containers 4b, 5b, 6b that are pulled out integrally with the doors provided in front of the respective storage compartments. The storage containers 4b, 5b, and 6b can be pulled out by placing the hand on (not shown) and pulling it out to the front side. Similarly, the ice making chamber 3 is provided with a storage container 3b that is pulled out integrally with the ice making chamber door 3a so that the handle (not shown) of the ice making chamber door 3a can be pulled out to the front side.

  The temperatures of the evaporator 7 and each storage room, which will be described later, are as follows: an evaporator temperature sensor 36 provided at the top of the evaporator 7, a refrigerator temperature sensor 33 provided in the refrigerator room 2, and a vegetable room temperature sensor 34 provided in the vegetable room 6. The temperature is detected by a freezer temperature sensor 35 provided in the lower freezer room 5. Furthermore, as described above, the refrigerator 1 also includes the outside air temperature sensor 37 and the outside air humidity sensor 38 that detect the temperature and humidity outside the storage room.

  A control board 31, which is an example of a control device on which a CPU, a memory such as a ROM and a RAM, an interface circuit, and the like are mounted, is disposed on the ceiling wall surface of the refrigerator 1. The control board 31 detects the open / closed state of each door, as described above, for the outside air temperature sensor 37, the outside air humidity sensor 38, the evaporator temperature sensor 35, the refrigerating room temperature sensor 33, the vegetable room temperature sensor 34, the freezer room temperature sensor 35, respectively. It is connected to a door sensor (not shown). The aforementioned CPU controls the ON / OFF of the compressor 24 and the storage chamber fan 9, which will be described later, the rotational speed (the number of revolutions per hour), etc., based on these output values and the programs recorded in the ROM. Control of the three-way valve (refrigerant flow path control means) 112, control of each stepping motor (not shown) for individually opening and closing the refrigerator compartment damper 50, the vegetable compartment damper (not shown), and the freezer compartment damper 52, etc. Is going.

  The evaporator 7 that cools the air in the refrigerator 1 is provided in an evaporator storage chamber 8 that is formed between the freezer compartment 60 and the back wall of the heat insulating box 10. The air cooled by exchanging heat with the evaporator 7 is sent to the refrigerating room 2 through the refrigerating room duct 11 by the storage room fan 9 provided above the evaporator 7, and the vegetable room duct (not shown). ) To the vegetable compartment 6. Similarly, the air cooled by the evaporator 7 is sent to the storage rooms of the ice making room 3, the upper freezing room 4, and the lower freezing room 5 through the freezing room duct 13. The air blowing to each storage room is controlled by opening and closing the refrigerator compartment damper 50, the vegetable compartment damper (not shown), and the freezer compartment damper 52 in conjunction with the temperature sensors 33, 34, 35 provided in each storage compartment. Yes. The air that has cooled the refrigerator compartment 2, the freezer compartment 60, and the vegetable compartment 6 returns to the evaporator storage compartment 8 via the refrigerator compartment return duct (not shown), the freezer compartment return duct 17, and the vegetable compartment return duct 18, respectively. It is cooled again by the evaporator 7.

  In addition, a defrost heater 22 that heats frost attached to the evaporator 7 during the defrosting operation is installed below the evaporator 7. The defrosted water generated by the defrosting flows into the eaves 23 provided in the lower part of the evaporator storage chamber 8 and then is discharged to the evaporating dish 21 disposed in the machine chamber 19 described later via the drain pipe 27. .

  FIG. 3 is a diagram for explaining a configuration of a refrigeration cycle (refrigerant flow dew) relating to the embodiment. In the refrigerator 1 of the present embodiment, the compressor 24, the heat radiation means 41 that is a heat radiation means for radiating the refrigerant, the wall surface heat radiation pipe 42, and the condensation on the front surfaces of the partition walls 28, 29, and 30, that is, the opening edge. Condensation prevention piping 43 for suppressing, first capillary tube 44d and second capillary tube 44e which are decompression means for decompressing the refrigerant, and an evaporator for absorbing heat in the storage chamber by exchanging heat between the refrigerant and the air in the storage chamber 7 to cool the storage chamber. In addition, a dryer 45 that removes moisture in the refrigeration cycle, a gas-liquid separator 46 that prevents liquid refrigerant from flowing into the compressor 24, a refrigerant junction 200, and a three-way valve 112 are also provided. These are connected by connecting pipes 72, 73, 74, 86, 87, 88, 89, 80, 81, 82, 83, 84, respectively, thereby constituting a refrigeration cycle. In addition, the refrigerator 1 of a present Example uses isobutane as a refrigerant | coolant. In addition, the compressor 24 of this embodiment includes an inverter and can change the rotation speed. However, if the compressor 24 is driven at an excessively low speed, the lubricating oil in the compressor 24 becomes difficult to flow. Has a lower limit.

  In the refrigerator 1 of the present embodiment, the first capillary tube 44d and the second capillary tube 44d and the second capillary tube depressurize the refrigerant by friction generated between the refrigerant and the inner wall of the pipe by passing through the refrigerant flow path having a small cross-sectional area as the pressure reducing means. The capillary tube 44e is provided with two capillary tubes. The first capillary tube 44d and the second capillary tube 44e are collectively referred to as a capillary tube 44. The first capillary tube is adjusted so as to have an appropriate throttle strength with a small heat load. Here, the strength of the throttling indicates the ease of pressure reduction. In the capillary tube 44, the narrower the inner diameter of the tube, the stronger the throttling, and the longer the length, the stronger the throttling. The second capillary tube 44e is adjusted so as to have an appropriate throttle strength in a state where the heat load is large, and has a narrower throttle strength than the first capillary tube 44d.

  The refrigerant junction part 200 is a member that connects three connection pipes, and always connects the three connection pipes connected to the refrigerant junction part. The refrigerant junction 200 is in communication with the connection pipes 80, 81, 82.

  The three-way valve 112 switches between a D mode for communicating the inlet 112i and the outlet 112o_D and an E mode for communicating the inlet 112i and the outlet 112o_E. In addition, there are three modes of the X mode in which both the outlet 112o_D and the outlet 112o_E of the three-way valve 112 are closed.

  The refrigerant that has become high-temperature and high-pressure by the compressor 24 flows into the outside-storage-room radiator 41 and the wall surface radiation pipe 42 via the connection pipes 72 and 73 and radiates heat. Thereafter, the refrigerant also radiates heat in the dew condensation prevention pipe 43 via the connection pipe 74. Due to the heat radiation from the dew condensation prevention pipe 43, the opening edge (see FIG. 2) of the storage quality, which is the front surface portion of the partition walls 28, 29, and 30, is heated.

  The refrigerant that has flowed out of the dew condensation prevention pipe 43 flows into the dryer 45 via the pipe 86, and then when the three-way valve 201 flowing into the three-way valve 112 via the connection pipe 87 is in the D mode, The refrigerant flows into the refrigerant confluence 200 through the one capillary tube 44d, and flows into the refrigerant confluence 200 through the connection pipes 89 and 81 and the second capillary tube 44e when the three-way valve 201 is in the E mode. Further, when the three-way valve 201 is in the X mode, the refrigerant does not flow into the connection pipes 88 and 89.

  The refrigerant is depressurized by the capillary tube 44 to become a low pressure, and because the refrigerant becomes a low pressure, a part of the refrigerant evaporates and the heat of vaporization is taken away, resulting in a low temperature. The low-temperature and low-pressure refrigerant absorbs heat from the air in the storage chamber in the evaporator 7 that has flowed in through the refrigerant junction 200 and the connection pipe 82. Due to the heat absorption of the refrigerant, the air in the storage chamber is cooled and the refrigerant further evaporates. The refrigerant that has flowed out of the evaporator 7 returns to the compressor 24 via the connection pipe 83, the gas-liquid separator 46, and the connection pipe 84.

Next, the installation location of each member constituting the refrigeration cycle shown in FIG. 3 will be described.
FIG. 4 is a schematic diagram when the inside of the machine room is viewed from the back. As shown in FIG. 2, the refrigerator 1 includes a machine room 19 on the outside of the heat insulating box 10, below the back of the vegetable room 6 of the refrigerator 1 and below the evaporator storage room 8. Machine room openings 19 a and 19 b are formed on the wall surface of the refrigerator 1 constituting both sides of the machine room 19, and outside air is transferred from the machine room opening 19 a to the machine room by a fan 41 outside the storage room provided in the machine room 19. It has a structure that can flow into 19 and flow out from the machine room opening 19b. In the machine room 19, a machine room opening 19a, a storage room radiator 41, a storage room fan 41a, a compressor 24, a three-way valve 112, and a machine room opening 19b are arranged in order from the right in the drawing. . The dryer 45 is disposed at the upper position of the three-way valve 112, and the evaporating dish 21 is disposed at the upper portion of the compressor 24 and at the lower portion of the drain pipe 27.

  During the cooling operation, the compressor 24 and the outdoor storage room radiator 41 that are at a high temperature drive the external storage room fan 41a to exchange heat with the outside air taken in from the machine room opening 19a to radiate heat. Therefore, the heat radiation amount of the compressor 24 and the outdoor storage room radiator 41 can be adjusted by changing the rotational speed of the external storage room fan 41a and the ON / OFF of the external storage room fan 41a. Since the air heated by the heat radiation from the compressor 24 and the heat radiator 41 outside the storage room is pressurized by the fan 41a outside the storage room, it is discharged from the machine room opening 19b to the outside of the machine room 19 having a relatively low pressure. The Further, drain water generated at the time of defrosting is discharged from the drain pipe 27 to the evaporating dish 21 and evaporated by heat from the compressor 24 and the outdoor radiator 41.

  FIG. 5 is a diagram showing the arrangement positions of the wall surface heat radiation pipe 42 and the dew condensation prevention pipe 43. As shown in FIG. 3, the wall surface heat radiation pipe 42 and the dew condensation prevention pipe 43 are members through which a high-temperature and high-pressure refrigerant flows.

  The wall surface heat radiation pipe 42 is disposed between the outer box 1a and the inner box 1b of the refrigerator 1 (see FIG. 2) so as to be in contact with the outer surface of the outer box 1a. The outer box 1a is made of a steel plate, and the high-temperature refrigerant in the wall surface heat radiation pipe 42 radiates heat to the air outside the storage chamber via the outer surface of the outer box 1a. In addition, the dew condensation prevention pipe 43 is disposed in front of the refrigerator compartment / freezer compartment partition wall 28, the freezer compartment / vegetable compartment partition wall 29, and the compartment compartment wall 30 of the freezer compartment (part indicated by a one-dot chain line in FIG. 5). As shown in FIGS. 1 and 2, the front portions of the partition walls 28, 29, and 30 form the opening edges of the ice making chamber 3, the upper freezing chamber 4, and the lower freezing chamber 5.

Next, details of the vicinity of the dew condensation prevention pipe 43 will be described using the freezer compartment partition wall 30 as a representative.
FIG. 6 is an enlarged cross-sectional view of the freezer compartment partition wall 30. Inside the freezer compartment partition wall 30, a dew condensation prevention pipe 43 through which the refrigerant that has become high temperature and high pressure in the compressor 24 flows is provided. The dew condensation prevention pipe 43 is provided in the vicinity of the partition cover 30 a provided on the front surface portion of the freezer compartment partition wall 30. In addition, although the partition cover 30a of the refrigerator 1 in connection with a present Example is a product made from a steel plate, it is not limited to this, What is necessary is just to comprise with materials, such as a metal with high heat conductivity. Since the freezer compartment partition wall 30 is adjacent to the freezer compartment 60 that keeps the room in a freezing temperature zone (for example, about −18 ° C.), when the heating means is not provided, the freezer compartment partition wall 30 is a freezer compartment. It is cooled by 60 low-temperature air and becomes cooler than the outside air around the refrigerator 1. Therefore, if the outside air around the refrigerator 1 is highly humid, the surface temperature of the partition cover 30a is likely to be lower than the dew point temperature, and condensation may occur on the surface of the partition cover 30a due to moisture in the air near the partition cover 30a. is there. On the other hand, as shown in FIG. 3, by providing a condensation prevention piping 43 in the vicinity of the partition cover 30a through which the high-temperature refrigerant before being depressurized by the capillary tube 44 flows, the heat flow 91 in FIG. The partition cover 30a is heated with a refrigerant to suppress condensation generated on the partition cover 30a.

  The front portions of the freezer compartment-freezer compartment partition wall 28 and the freezer compartment-vegetable compartment partition wall 29 are members that form the opening edge of the freezer compartment 60 in the same manner as the freezer compartment partition wall 30 and are shown in FIG. A dew condensation prevention pipe 43 is provided in the vicinity of a partition cover (not shown) provided on the front surface of each partition wall 28, 29 with the same configuration as the freezer compartment partition wall 30. Heating.

  FIG. 7 is a schematic cross-sectional view showing an outline of the heat exchanging portion 47 of the refrigerator. The refrigerator 1 of the present embodiment is provided with a heat exchanging portion 47 in which a first capillary tube 44d and a second capillary tube 44e are disposed in the vicinity of the refrigerant pipe 84. The first capillary tube 44d and the second capillary tube 44e are provided on opposite sides of the refrigerant pipe 84, respectively. The heat exchanging portion 47 is formed inside the heat insulating box 10. Low temperature refrigerant flows into the refrigerant pipe 84 connected to the outlet side of the evaporator 7, while high temperature refrigerant from the heat radiating side flows into the capillary tube 44. Therefore, when the refrigerant flows through the first capillary tube 44d, a heat flow 93a is generated from the first capillary tube 44d toward the refrigerant pipe 84, and heat exchange is performed. Similarly, when the refrigerant flows through the second capillary tube 44e, a heat flow 93b is generated from the second capillary tube 44e toward the refrigerant pipe 84.

  Next, the action of the heat exchanging portion 47 and the state change of the refrigerant on the heat radiation side from the compressor 24 to the capillary tube 44 will be described with reference to FIGS.

  FIG. 8 is a diagram showing the state of the refrigerant in each part of the refrigeration cycle on the Mollier diagram. FIG. 9 is a view showing the state of the refrigerant in the piping from the compressor 24 to the capillary tube 44. 8 and 9 show the case where the refrigerant circulates on the first refrigerant flow path A side.

  In FIG. 8, the vertical axis represents the refrigerant pressure, and the horizontal axis represents the specific enthalpy of the refrigerant. The refrigerant states B to E, H, and I shown in FIGS. 8 and 9 represent the same state in FIGS. 8 and 9.

  Since the refrigerant in the state A flowing into the compressor 24 is compressed by the compressor 24, the specific enthalpy of the refrigerant increases from h1 to h2, and the pressure increases from P1 to P2 (states A to B). The refrigerant (state B) that has been compressed to high temperature and high pressure is in the order of the outdoor radiator 41 (state B to C), the wall surface radiator 42 (state C to D), and the dew condensation prevention pipe 43 (state D to E). As a result of heat dissipation, the specific enthalpy of the refrigerant decreases from h2 to h3. The refrigerant that has reached the state E exchanges heat with the refrigerant in the connection pipe 84 in the heat exchange section 47 while being depressurized when passing through the first capillary tube 44d, so the specific enthalpy decreases from h3 to h4, The refrigerant pressure decreases from P2 to P1 (states E to F). Thereafter, the refrigerant (state F) at the inlet of the evaporator 7 absorbs heat by exchanging heat with the air in the storage chamber, and the specific enthalpy of the refrigerant increases from h4 to h5 (states F to G). The refrigerant (state G) at the outlet of the evaporator 7 returns to the compressor 24 again after the specific enthalpy of the refrigerant increases from h5 to h1 due to the heat moving from the first capillary tube 44d in the heat exchange unit 47 ( State G to A). During the circulation of the state A-B-C-D-E-F-G shown on the Mollier diagram, the refrigerant is roughly divided into three states: a gas phase region, a gas-liquid two-phase region, and a liquid phase region. Change.

  Here, the state of the refrigerant from the outlet (B) of the compressor 24 on the heat radiation side of the refrigeration cycle to the inlet (E) of the first capillary tube 44d will be considered using FIG. The point where the gas phase changes from the gas-liquid two-phase region is H, the point where the gas-liquid two-phase region changes from the liquid-phase region is I, the gas refrigerant is 94, the liquid refrigerant is 95, and the gas refrigerant 94 only. The gas phase region is represented by the section BH, the gas-liquid two-phase region where the gas refrigerant 94 and the liquid refrigerant 95 are mixed is represented by the section HI, and the liquid phase region of the liquid refrigerant 95 alone is represented by the section IE.

  In FIG. 9, the refrigerant flows from symbol B to E, and the gas refrigerant 94 compressed to the high temperature and high pressure by the compressor 24 is stored in the order of the outdoor heat radiator 41, the wall surface heat radiation pipe 42, and the dew condensation prevention pipe 43. Heat is radiated to the outside, and the state of the refrigerant changes in the order of the gas phase region (section BH), the gas-liquid two-phase region (section HI), and the liquid phase region (section IE). In the refrigerator 1 of the present embodiment, the gas-phase region reaches the gas-liquid two-phase region in the middle of the outdoor storage radiator 41, and reaches the liquid-phase region in the middle of the dew condensation prevention pipe 43. Therefore, the proportion of the gas refrigerant 94 is large in the outdoor radiator 41 and the proportion of the liquid refrigerant 95 is large in the dew condensation prevention pipe 43. The liquid refrigerant 95 has a higher density than the gas refrigerant 94. For example, in isobutane, the density ratio of the gas refrigerant 94 and the liquid refrigerant 95 is about 1:50 at a condensation temperature of 30 ° C. Therefore, since the ratio of the liquid refrigerant 95 is large in the dew condensation prevention pipe 43, the amount of refrigerant contained in the dew condensation prevention pipe 43 is larger than the pipe internal volume.

  Next, the operation of the heat exchange unit 47 shown in FIGS. 3 and 7 will be described with reference to FIG. The specific enthalpy of the refrigerant (state F) at the inlet of the evaporator 7 is reduced from h3 to h4 by the heat exchanging unit 47, and the heat absorption amount (h5-h4) in the evaporator 7 is increased. Since the cooling efficiency (= endothermic amount (h5-h4) / consumed energy (h2-h1)) is improved by increasing the endothermic amount in the evaporator 7, the refrigerator 1 of the present embodiment is provided with a heat exchanging portion 47. Energy saving performance.

Next, the relationship between the evaporation pressure and the energy saving performance will be described.
In FIG. 10, the state when the evaporation pressure is lower than the refrigeration cycle (dotted line) shown in FIG. 8 is indicated by a solid line on the Mollier diagram. When the evaporation pressure P1 decreases to P1 ′, the difference between the condensation pressure P2 and the evaporation pressure P1 ′ becomes larger than the difference between P2 and P1 before the evaporation pressure decreases. Therefore, the energy consumed by the compressor 24 increases from (h2−h1) to (h2′−h1). Therefore, when the heat load is large (see FIG. 11b), the difference between P2 and P1 is reduced by weakening the throttle of the refrigeration cycle, and the operation with high energy saving performance is performed.

  On the other hand, a cooling operation in which the evaporation temperature is lowered (evaporation pressure is lowered) may be necessary. For example, when the food load is small and the heat load is small and the storage chamber is sufficiently cold, it is necessary to lower the evaporation temperature in response to a decrease in the storage chamber temperature. As means for lowering the evaporation temperature (evaporation pressure), it is conceivable to increase the decompression amount of the refrigerant by increasing the throttle and to increase the rotational speed of the compressor 24. If the value is lowered, the compressor 24 can be driven at a low speed and the energy consumption of the compressor 24 can be reduced, so that the operation with high energy saving performance can be performed.

  From the above, it can be seen that controlling the evaporation pressure by changing the squeezing strength of the refrigeration cycle in accordance with the heat load leads to an improvement in energy saving performance.

  In the refrigerator 1 according to the present embodiment, the capillary tube 44d has a throttle strength suitable for conditions with a small heat load, and the capillary tube 44e has a specification suitable for a large heat load. As a result, when the heat load is small, the refrigerant can be flowed through the capillary tube 44d and when the heat load is large, the refrigerant can be flowed through the capillary tube 44e to obtain an appropriate throttle strength, and a cooling operation with high energy saving performance can be performed. .

  The main configuration of the refrigerator 1 according to the present embodiment has been described above. Next, the effect | action to the refrigerating cycle by the frost formation to the evaporator 7 is demonstrated using FIG. Since frost hinders heat exchange between the evaporator and the air around the evaporator, it acts to lower the evaporator pressure P1. Further, since the evaporator 47 and the compressor 24 are connected by the pipe 84, when the evaporation pressure is reduced, the suction steam pressure of the compressor 24 is similarly reduced. As a result, the refrigerant circulation rate is reduced. Therefore, when the frost is increased in the evaporator 47, the refrigerating capacity and the energy saving performance are reduced.

  Further, as described above, at each partition wall 28, 29, 30, dew condensation is prevented by flowing a high-temperature refrigerant through the dew condensation prevention pipe 43. Therefore, when the refrigerant circulation amount is reduced due to frost formation on the evaporator 47, the flow rate of the high-temperature refrigerant flowing in the dew condensation prevention pipe 43 is similarly reduced, and the ability to overheat the partition wall is reduced.

  In this way, the frost formation on the evaporator may cause a decrease in cooling performance, a decrease in energy saving performance and a decrease in dew condensation prevention function, and therefore the refrigerator 1 periodically sets a maximum time for defrosting. Defrosting prevents excessive frost formation on the evaporator 47. In addition, the amount of frost formation on the evaporator is predicted by combining a plurality of conditions, and when it is determined that there is frost formation above a certain level, control is performed to perform defrosting even before the aforementioned maximum time has elapsed. .

  On the other hand, the defrosting operation in a household refrigerator often has a large amount of power consumption compared to a normal cooling operation. Therefore, the longer the defrosting section, the easier it is to save energy. Therefore, in the refrigerator 1, the following control is performed to achieve both prevention of performance degradation due to a decrease in evaporation pressure and energy saving.

  Next, control will be described with reference to FIG. In the control of this embodiment, the amount of frost formed on the evaporator is predicted using a door sensor (not shown) or a timer of the CPU of the refrigerator 1, and the three-way valve 112 is switched according to the predicted amount of frost formed. The evaporation pressure is controlled by Details will be described below.

  The frost formation amount determination value is obtained from the integrated value of the timer of the CPU of the refrigerator 1 and the door opening time detected by the open / closed state sensors attached to the refrigerator compartment door, the freezer compartment door, and the vegetable compartment door.

  As one of the routes through which moisture enters the refrigerator, inflow of outside air when the doors 2a, 2b, 3a, 4a, 5a, 6a of the respective storage rooms are opened is considered. At this time, the maximum amount of air exchanged depends on the internal volume of the chamber with the door opened. Since the storage chamber volume is a fixed value, the amount of water flowing in can be predicted. In addition, more accurate prediction is possible by measuring the door opening time with a timer in the CPU and predicting the amount of air exchange and estimating the state of the outside air with the outside air temperature sensor 37 and the outside air humidity sensor 38. It becomes. Moreover, although inflow of the water | moisture content by the evaporation from the foodstuff in a storage chamber is also considered, in the refrigerator 1, it estimates that the input amount of food depends on the opening time of a storage chamber.

  As another moisture ingress path, the inflow of outside air from the gap between the heat insulating box 10 and the doors 2 a, 2 b, 3 a, 4 a, 5 a, 6 a of each storage chamber or the drain pipe 27 can be considered. Since it is considered that a certain amount of air is exchanged in a state where the operation of the refrigerator is stable, the amount of frost formation can be predicted by measuring the elapsed time after defrosting with a timer.

From the above, in the refrigerator 1, the total value of the value obtained by multiplying the door opening time by a coefficient and the value obtained by multiplying the operation time after defrosting by another coefficient is used as the frost amount determination value. Also, the door opening factor is assigned a different value to each of the doors 2a, 2b, 3a, 4a, 5a, 6a, and a larger value is assigned to the door of the corresponding storage chamber having a larger internal volume. Yes. The frost amount determination value is integrated over time, but the integration is restarted from 0 when the defrosting is completed.
Next, switching conditions of the valve 112 using the frost amount determination value will be described. In addition to the frost amount determination value, prohibition determination values SjA and SjB, which are fixed values provided in advance, are used for switching. The prohibition determination values SjA and SjB are determined for the capillary tubes 44d and 44e of the refrigerator 1, respectively. When the frost formation amount determination value exceeds the prohibition determination value, switching to the assigned capillary tube is prohibited. However, the smaller the inner diameter of the capillary tube, the smaller the prohibition determination value, and at least one capillary tube can always be used regardless of the frost formation amount determination value.

  When the frosting amount determination value reaches the prohibition determination value (SjA, SjB), switching to the mode corresponding to the prohibition determination value at which the three-way valve 112 flows out the refrigerant to the capillary tube 44 is prohibited. The prohibition determination value is determined for each capillary tube 44 of the refrigerator 1. However, the smaller the inner diameter of the capillary tube, the smaller the prohibition determination value, and at least one capillary tube can always be used regardless of the frost formation amount determination value. The refrigerator 1 uses the same frost formation amount determination value for determining the defrost period. The prohibition determination value of the capillary tube 44d is 90% of the defrost period, and the capillary tube 44e that is thicker than the capillary tube 44d is not provided with a prohibition determination, and can always be used regardless of the frost formation amount determination value.

  The refrigerator 1 discusses a refrigerator configured using two capillary tubes 44d and 44e. Similarly, when a larger number of capillary tubes are used, the use of thin capillary tubes is prohibited. Set the prohibition judgment value to. In addition, it is necessary that at least one capillary tube can always be used regardless of the frost formation amount determination value.

  In the embodiment, the pressure reduction amount is adjusted by switching the plurality of capillary tubes 44. Similarly, when other pressure reducing means such as an expansion valve is used, a region where the throttle amount is large is used to increase the frost formation amount determination value. The same effect can be obtained by prohibiting it.

  In the refrigerator 1, the total value of the elapsed time after defrosting and the time when the refrigerator door is opened is used as the frosting amount determination value, but any calculation can be performed as long as the defrosting amount can be estimated. You may go. For example, if there is a means to detect the outside air temperature and humidity around the refrigerator, the amount of water vapor flowing into the storage room from the outside (frosting) can be calculated by using the outside air temperature, outside air humidity, storage room capacity, etc. along with the door opening time. It is also possible to perform a calculation that yields an approximation of the quantity. In addition, a frost amount sensor that acquires the amount of frost that has formed is also being developed. If the amount of frost formation can be detected more accurately, the energy saving property can be improved.

1 Refrigerator
2 Refrigerated room (storage room)
3 Ice making room (storage room)
4 Upper freezer room (storage room)
5 Lower freezer compartment (storage room)
6 Vegetable room (storage room)
7 Evaporator
9 Storage room fan
10 Insulated box
24 Compressor
28 Cold room-freezer compartment partition (partition)
29 Freezer compartment-vegetable compartment partition wall
30 Freezer compartment partition wall (partition)
33 Cold room temperature sensor
34 Vegetable room temperature sensor
35 Freezer temperature sensor
36 Evaporator temperature sensor
37 Outside temperature sensor
38 Outside air humidity sensor
41 Heatsink outside storage room (heat dissipation means)
41a Fan outside storage room
42 Wall heat radiation piping (heat radiation means)
43 Anti-condensation piping
44 Capillary tube (pressure reduction means)
44d first capillary tube
44e Second capillary tube
45 dryer
46 Gas-liquid separator
47 Heat exchanger
50 Cold room damper
52 Freezer compartment damper
60 Freezer
112 Three-way valve (refrigerant flow path control means)
200, 201 Refrigerant junction

Claims (4)

A heat insulating box having an opening edge that forms an opening in the front, a door that opens and closes the opening, a storage chamber formed by the door and the heat insulating box, a compressor, and a discharge from the discharge port of the compressor In the refrigerator provided with the refrigerant flow path for flowing the refrigerant to be radiated, the dew condensation prevention pipe, the pressure reducing means, the evaporator, the suction port of the compressor in this order,
The refrigerator characterized in that the temperature of the opening edge is controlled by changing the squeezing amount of the decompression means. A door opening / closing sensor for detecting the opening / closing state of the door, and a timer for measuring an elapsed time from a certain time,
When the sum of a value obtained by multiplying the opening time of the door by a coefficient, and a value obtained by integrating a product of the coefficient corresponding to the number of rotations of the compressor and the elapsed time from the end of defrosting reaches a specified value. The refrigerator according to claim 1, wherein the amount of squeezing by the decompression means is reduced.   A temperature sensor that measures the temperature around the refrigerator; and a temperature sensor that measures the temperature of the opening edge, and the temperature of the opening edge is higher than the dew point temperature around the refrigerator predicted from the temperature around the refrigerator. The refrigerator according to claim 1, wherein when it is low, the amount of squeezing by the decompression unit is reduced.   The refrigerator according to claim 3, further comprising a humidity sensor that measures the humidity of the opening edge, wherein when the humidity of the opening edge becomes equal to or higher than a certain level, the amount of squeezing by the decompression unit is reduced.

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