JP2006003062A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator for improving return performance of refrigerating machine oil to a compressor. <P>SOLUTION: This refrigerator has a control means having a displacement control means 133 for changing displacement of the compressor 132. The compressor 132 is arranged in a top surface part or a back face upper part of a refrigerator body 100. Since the displacement per unit time of the compressor 132 increases and a volume flow rate per unit time of a refrigerant increases by having a refrigerating cycle using mineral oil as the refrigerating machine oil with a hydrocarbon as the refrigerant, a sufficient flow rate in a pipe can be secured for returning the refrigerating machine oil delivered from the compressor 132 to the compressor 132. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigerator that improves the return of refrigeration oil in a refrigeration cycle to a compressor.

  In recent years, refrigerators are required to be further energy-saving from the viewpoint of protecting the global environment and to be improved in usability and storage.

  In the conventional refrigerator of this type, a compressor or the like forming a machine room is installed on the top surface of the refrigerator body, which is inconvenient in view of the storage capacity of the refrigerator, or on the upper back of the refrigerator body. (For example, see Patent Document 1).

  FIG. 12 shows a configuration of a conventional refrigerator described in Patent Document 1. As shown in FIG.

  The refrigerator main body 1 is composed of a refrigerator compartment 2, a vegetable compartment 3, and a freezer compartment 4 from above. The refrigerator compartment 2 has a rotary door 5, the vegetable compartment 3 is a vegetable compartment drawer door 6, and the freezer compartment 4 is a freezer compartment. A drawer door 7 is provided. In this configuration, the cooling unit 10 including the internal fan 8, the evaporator 9, and the like is set to a height that is substantially the same as the height of the opening of the freezing chamber 4 that forms a storage unit as the lowermost storage chamber. The compressor 12 and the like forming the machine room 11 are installed on the top surface of the refrigerator room 2 which is not convenient in view of the storage capacity of the refrigerator, or on the upper rear part of the refrigerator body 1. Yes.

With this configuration, the volume of the machine room 11 has moved from the lower side to the upper side of the partition wall that partitions the refrigerator room 2 and the vegetable room 3, so that the internal volume of each storage room is inevitably constant. And the position of the partition wall of the vegetable compartment 3 can be lowered | hung below, and the taking-out of the storage thing in the vegetable compartment 3 becomes easy.
JP-A-11-183014

  However, in the above-described conventional configuration, the rising height of the joint pipe connecting the evaporator outlet and the compressor is increased by disposing the compressor on the top surface of the refrigerator body and the evaporator near the bottom surface of the refrigerator body. For example, the heat insulation performance of the refrigerator body is improved by reducing the thermal conductivity of the urethane that makes up the refrigerator body, and the application of vacuum insulation, etc., and the compressor capacity can be reduced accordingly, so the refrigerant circulation rate is greatly reduced To do. In connection with this, the flow rate of the refrigerant | coolant in piping fell, and there existed a subject that the return amount to the compressor of refrigeration oil decreased.

  In addition, the refrigeration oil staying in the evaporator is returned to the compressor together with the refrigerant by the thermosiphon effect of the refrigerant during the defrosting of the evaporator in addition to the operation of the compressor, but the solubility of the refrigerant in the refrigeration oil is reduced. If it is small, there is a problem that it is difficult to be carried to the compressor together with the refrigerant, and the amount of return to the compressor is reduced.

  The present invention solves the above-described conventional problems, improves the return of refrigeration oil in the refrigeration cycle to the compressor, and improves the reliability of the refrigeration cycle in which the compressor is disposed above the evaporator. The object is to provide a refrigerator.

  In order to solve the above-described conventional problems, a refrigerator according to the present invention includes a compressor, a condenser, a decompressor, and an evaporator in order to form a series of refrigerant flow paths, and an exhaust capacity of the compressor. Control means provided with an exhaust capacity control means for changing the compressor, the compressor is disposed above the evaporator, the refrigeration cycle is filled with hydrocarbons as refrigerant and mineral oil as refrigeration oil, The exhaust capacity of the compressor is variable by the exhaust capacity control means.

  By using hydrocarbons as the refrigerant, for example, the refrigeration capacity per unit volume of the hydrocarbon is reduced to about ½ compared with the conventional case, compared with the case where the conventional refrigerant is R134a which is an alternative chlorofluorocarbon refrigerant. Therefore, the cylinder volume of the compressor can be increased to about twice in order to ensure the same refrigeration capacity, thereby increasing the volume flow rate of the refrigerant, and the flow rate in the piping during the compressor operation is increased. To increase.

  Moreover, the use of mineral oil as the refrigerating machine oil increases the solubility of the refrigerant in the refrigerating machine oil as compared with the conventional combination of R134a and ester oil.

  Also, by making the displacement of the compressor variable by the displacement control means that changes the displacement of the compressor, the amount of refrigerating machine oil brought out due to refrigerant discharge from the compressor can be reduced and the amount of refrigeration can be reduced. For some refrigerating machine oil taken out during the cycle, the return to the compressor can be improved by using a mineral oil that is compatible with the refrigerant flow rate enhancement by the hydrocarbon conversion of the refrigerant.

  The refrigerator of the present invention can secure a sufficient flow rate for the refrigeration oil to rise and rise through the piping by increasing the flow rate in the piping during compressor operation, and the return amount of the refrigeration oil from the evaporator to the compressor The reliability of the refrigerator can be improved by increasing the size.

  In addition, by using refrigeration oil that increases the solubility of the refrigerant in the refrigeration oil, it is possible to increase the return amount of the refrigeration oil from the evaporator to the compressor together with the refrigerant using the thermosiphon effect even during defrosting. Reliability can be improved.

  The invention according to claim 1 is a refrigeration cycle comprising a compressor, a condenser, a decompressor and an evaporator in order to form a series of refrigerant flow paths, and an exhaust capacity control means for changing the exhaust capacity of the compressor. The compressor is disposed above the evaporator, and the refrigeration cycle is filled with hydrocarbon as refrigerant and mineral oil as refrigeration oil, and the exhaust capacity control means Since the displacement of the compressor is variable, the displacement of the compressor per unit time increases as compared with R134a and the like, and the volume flow rate of the refrigerant per unit time increases, so that the refrigeration discharged from the compressor Enough flow rate in the piping to allow the machine oil to return to the compressor, and increasing the solubility of the refrigerant in the refrigeration oil reduces the viscosity of the refrigeration oil by melting the refrigerant into the refrigeration oil. Rukoto can be more increased return amount of the refrigerating machine oil to the compressor from the evaporator.

  Furthermore, by making the displacement of the compressor variable by means of the exhaust capacity control means, the amount of refrigeration oil taken out due to refrigerant discharge from the compressor is reduced during low displacement control, and part of the refrigeration cycle is taken out For the refrigerating machine oil, the return to the compressor can be improved by using a mineral oil that is compatible with the refrigerant flow rate enhancement by the hydrocarbonation of the refrigerant.

  According to a second aspect of the present invention, in the first aspect of the present invention, a control unit including an exhaust capacity control unit and an internal temperature detection unit are provided, and a predetermined timing based on detection information of the internal temperature detection unit. Thus, by controlling the exhaust capacity of the compressor and increasing the refrigerant circulation flow rate of the refrigeration cycle, it is possible to ensure the circulation of the refrigeration oil at the same time as necessary.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the exhaust capacity control means is forcibly operated for a predetermined time at the time of starting the compressor at a larger exhaust capacity than during normal control. Since the compressor starts up at a high speed, the amount of discharged oil is maximized due to the refrigerating machine oil blending into the stopped refrigerant, and a reliable refrigerant flow rate in the pipe is ensured at the start of sliding when the lubrication conditions are worst. By doing so, it is possible to ensure the circulation of the refrigerating machine oil.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the compressor is disposed on a part of the top surface of the refrigerator body, and the evaporator to the compressor. Even when the rising distance of the return path of the refrigerant to the refrigerant becomes large, it is possible to ensure a sufficient flow rate in the pipe so that the refrigeration oil discharged from the compressor returns to the compressor, and the solubility of the refrigerant in the refrigeration oil It is possible to improve the returnability of the refrigerating machine oil from the evaporator to the compressor to ensure the reliability of the refrigerator.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the heat of the compressor that becomes high temperature is provided by disposing the condenser in a region away from the compressor. Since it is not affected, it is possible to reduce the size by shortening the pipe length. As a result, the condenser piping length can be shortened and the amount of liquid refrigerant in the high-pressure piping can be reduced, reducing the amount of refrigerating machine oil mixed with the liquid refrigerant in the high-pressure piping and improving the refrigerating machine oil circulation. Can be made.

  According to a sixth aspect of the invention, in the invention of the fifth aspect, by arranging the condenser at the lower part of the refrigerator body, a room whose temperature is relatively lower than the upper part of the room in view of a general indoor temperature distribution. Heat can be exchanged with the lower temperature air in the lower part, and further downsizing is possible. Thereby, since the amount of liquid refrigerant staying in the high-pressure pipe can be further reduced, the amount of refrigerating machine oil mixed with the liquid refrigerant in the high-pressure pipe can be reduced, and the circulation performance of the refrigerating machine oil can be improved.

  According to a seventh aspect of the present invention, in addition to the invention according to any one of the first to sixth aspects, the compressor includes a sealed container, an electric element provided in the sealed container, and a compression element. The internal space of the refrigeration cycle is on the low-pressure side of the refrigeration cycle. In addition to the invention described in claim 1, the internal space of the closed vessel is compared with the case of the high-pressure side of the refrigeration cycle. The amount of refrigerating machine oil discharged to the compressor can be reduced, the absolute amount of refrigerating machine oil remaining in the refrigerant piping related to the returnability of refrigerating machine oil can be reduced, and the risk of damage to the compressor due to a shortage of refrigerating machine oil in the compressor Can be further reduced.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals are given to the same configurations as those of the conventional examples of the background art or the embodiments described above, and detailed descriptions thereof are omitted. To do. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a schematic diagram of the refrigerator in Embodiment 1 of the present invention, and FIG. 2 is a solubility curve diagram of refrigerant and refrigerating machine oil in the same embodiment.

  The refrigerator main body 1 is provided with a refrigerator compartment 2 which is a relatively high temperature compartment in the upper part and a freezer compartment 4 which is a relatively low temperature compartment in the lower part, and has a so-called bottom freezer configuration. Yes. The refrigerator compartment 2 and the freezer compartment 4 are configured to be insulated from the surroundings with a heat insulating material such as urethane. Moreover, taking in and out of stored items such as food is performed through a heat insulating door (not shown).

  The refrigerator compartment 2 is usually set at 1 to 5 ° C. for refrigerated storage, but may be set at a slightly lower temperature, for example, −3 to 0 ° C. for improving the freshness, and may be used depending on the stored items. In some cases, a person can freely switch the temperature setting as described above. In addition, in order to preserve wine, root vegetables, etc., the temperature may be set slightly higher, for example, around 10 ° C.

  The freezer compartment 4 is usually set at −22 to −18 ° C. for frozen storage, but may be set at a lower temperature, for example −30 to −25 ° C., for improving freshness.

  A machine room 11 is formed on the upper surface of the refrigerator body 1, and the bottom surface of the machine room 11 is provided at a position lower than the first top surface part 13 and the first top surface part 13 on the back surface 14 side of the refrigerator outer box. The second top surface portion 15 is formed in a step shape. The condenser 16 is disposed in the upper space portion of the first top surface portion 13, and the compressor 12 is disposed in the upper space portion of the second top surface portion 15, and is made of a resin that covers the condenser 16 and the compressor 12. A machine room cover 17 as a cover is fixed to the refrigerator main body 1 with screws or the like.

  Here, since the evaporator 9 is disposed behind the freezer compartment 4, the height relationship between the compressor 12 and the evaporator 9 is such that the compressor 12 is disposed on a part of the top surface of the refrigerator body 1. The evaporator 9 is disposed in a part of the vicinity of the lower portion, and the refrigerant return path in the refrigeration cycle from the evaporator 9 to the compressor 12 has a relationship of having a considerable rising distance in the height direction. .

  The refrigeration cycle 18 is formed of a series of refrigerant flow paths that include a compressor 12, a condenser 16, a capillary 19 that is a decompressor, and an evaporator 9 in order.

  The compressor 12 is a reciprocating compressor that compresses refrigerant by reciprocating a piston in a cylinder.

  The compartment of the machine room 11 includes a first top surface part 13, a second top surface part 15, and a machine room cover 17.

  In the case of the refrigeration cycle 18 using a three-way valve or a switching valve, the functional parts may be disposed in the machine room 11 in the refrigerator body 1.

  In the present embodiment, the pressure reducing device constituting the refrigeration cycle 18 is the capillary 19, but there may be an electronic expansion valve that can freely control the flow rate of the refrigerant driven by the pulse motor.

  The operation and action of the refrigerator configured as described above will be described below.

  The high-temperature and high-pressure refrigerant discharged by the operation of the compressor 12 exchanges heat with the air above the refrigerator main body 1 in the condenser 16 to dissipate heat, condense and liquefy, and reach the capillary 19. Thereafter, the pressure is reduced by the capillary 19 while exchanging heat with the suction line 20, and the vapor reaches the evaporator 9.

  Due to the action of a cooling fan (not shown), the cool air having a relatively low temperature due to the evaporating action of the refrigerant in the evaporator 9 flows into the refrigerating room 2 and the freezing room 4 to cool the respective rooms. In the evaporator 9, the refrigerant that has exchanged heat with the air in the cabinet passes through the suction line 20 and is sucked into the compressor 12 together with the refrigerator oil.

  Thus, when the refrigeration cycle 18 is configured such that the compressor 12 is disposed above the evaporator 9, the compressor 12 is disposed on a part of the top surface of the refrigerator main body 1 as in the present embodiment. When the evaporator is arranged near the lower part of the refrigerator main body 1 and the rising distance of the return path of the refrigerant from the evaporator 9 to the compressor 12 becomes large, the refrigerant enters the refrigeration cycle 18 together with the refrigerant from the compressor 12. An important point related to the reliability of the compressor 12 is how to return the refrigeration oil discharged in the evaporator 9 and staying in an accumulator (not shown) in the evaporator 9 to the compressor 12 through the suction line 20.

  Further, regarding the return characteristics of the refrigeration oil in the start-up pipe, it is widely known that the flow rate of the refrigerant in the pipe depends more greatly, although the influence of the viscosity of the refrigeration oil can be considered.

  However, when the refrigerant flow rate is increased by increasing the cylinder capacity of the compressor 12 or increasing the rotation speed of the compressor 12 in order to ensure the refrigerant flow rate, and increasing the refrigeration capacity, the evaporator 9 causes a decrease in the evaporation temperature, and the compression ratio of the compressor 12 increases and the amount of power consumption increases. Therefore, it has been difficult to solve by these means.

  Therefore, in the present embodiment, for example, isobutane which is a hydrocarbon refrigerant is used as the refrigerant of the refrigeration cycle 18.

  (Table 1) shows physical properties in a saturated liquid of −30 ° C. of isobutane and a conventional alternative chlorofluorocarbon refrigerant such as R134a.

  As shown in Table 1, the refrigeration capacity per unit volume of isobutane is 520.8 kJ, whereas the refrigeration capacity per unit volume of R134a, which is a conventional alternative chlorofluorocarbon refrigerant, is 971.6 kJ. Compared with R134a, the refrigerating capacity per unit volume is about ½. Therefore, in order to make the refrigeration capacity of the compressor 12 equivalent to that of the conventional R134a, the cylinder volume of the compressor 12 is increased to about twice, and the displacement of the piston per unit time of the compressor 12 is also about the same. It increases to about 2 times. That is, since the volume flow rate of the refrigerant per unit time increases, the flow velocity in the pipe during the operation of the compressor 12 increases to about twice.

  Moreover, the refrigerating capacity per unit volume of CO2, which is a natural refrigerant, is 11258.5 kJ, and isobutane has a refrigerating capacity per unit volume of about 1/20 compared with CO2. Therefore, in order to make the refrigerating capacity of the compressor 12 equivalent to CO2, the cylinder volume of the compressor 12 is increased to about 20 times, and the displacement of the piston per unit time of the compressor 12 is also about 20 times as well. Increases to a degree. That is, since the volume flow rate of the refrigerant per unit time increases, the flow velocity in the pipe during the operation of the compressor 12 increases to about 20 times.

  As a result, even when the compressor 12 is disposed above the evaporator 9, the refrigeration oil staying in the evaporator 9 can be quickly returned to the compressor 12, and the refrigeration oil in the compressor 12 is insufficient. Therefore, the risk of damage to the compressor 12 can be reduced.

  In addition, the refrigerant staying in the evaporator 9 is returned to the compressor 12 together with the refrigerant by the thermosiphon effect of the refrigerant even when the evaporator 9 is defrosted by the action of a defrosting heater (not shown). It is. However, especially when the compressor 12 is arranged above the evaporator 9 and the suction line 20 as the start-up pipe is long, the refrigerant 12 is brought into the compressor 12 together with the refrigerant when the solubility of the refrigerant in the refrigerating machine oil is small. There was also a problem that the return amount of the refrigerating machine oil to be transported decreased.

  Therefore, mineral oil having good compatibility with isobutane is used as the refrigerating machine oil of the refrigeration cycle 18.

  FIG. 2 compares the solubility curves of the conventional case of combining R134a and ester oil with the case of combining the isobutane and mineral oil of the present embodiment. The horizontal axis represents the temperature of the refrigerant in the evaporator 9 (evaporation temperature), and the vertical axis represents the solubility (mass%) of the refrigerant dissolved in the refrigerating machine oil. According to this, the solubility increases in any case as the evaporation temperature in the evaporator 9 increases, but the difference increases as the evaporation temperature increases. Usually, the defrosting of the evaporator 9 is performed until the evaporator 9 reaches about 10 ° C. in anticipation of safety after the frost adhering to the evaporator 9 is melted. Therefore, when compared at a point where the temperature of the evaporator 9 is 10 ° C., the solubility when isobutane and mineral oil are combined is increased to about 50% as compared with the conventional case where R134a and ester oil are combined.

  Thus, even when the compressor 12 is disposed above the evaporator 9 and the entire length of the suction line 20 as a start-up pipe becomes long, the thermosiphon effect of the refrigerant is used together with the refrigerant during the defrosting. The amount of refrigerating machine oil returning from the compressor to the compressor 12 can be increased.

  In addition, when the compressor is an internal high pressure type, since the refrigeration oil sprayed in the internal space of the sealed container is discharged out of the compressor together with the discharge refrigerant, the compressor 12 of the present embodiment is an internal low pressure type, As a result, the amount of refrigerating machine oil discharged from the compressor 12 into the refrigerating cycle 18 can be suppressed, so that the absolute amount of refrigerating machine oil remaining in the refrigerant pipe related to the returnability of the refrigerating machine oil can be reduced. It is possible to further reduce the risk of damage to the compressor 12 due to the shortage of refrigeration oil inside, and also to suppress the efficiency reduction of the heat exchanger such as the evaporator 9 and the condenser 16 due to the staying refrigeration oil in the refrigerant pipe. it can.

  Moreover, even if the heat insulation performance of the refrigerator main body 1 is improved by, for example, reducing the thermal conductivity of urethane constituting the refrigerator main body 1 or applying a vacuum heat insulating material, and the need to reduce the capacity of the compressor 12 arises, As described above, the combination of isobutane, mineral oil, and internal low-pressure compressor 12 makes it easy to secure the necessary refrigerating machine oil in the compressor 12.

  In this embodiment, since the reciprocating compressor that compresses the refrigerant by reciprocating the piston in the cylinder is used as the compressor, the piston and the cylinder are separated from each other in comparison with the rotary compressor. Can be managed with relatively high accuracy. Therefore, sufficient sealing performance can be secured without using a large amount of refrigerating machine oil to seal between the piston and the cylinder, and the amount of refrigerating machine oil discharged together with the refrigerant discharged through the cylinder is also reduced. Therefore, the amount of refrigerating machine oil discharged from the compressor can be reduced, and the risk of damage to the compressor 12 due to the shortage of refrigerating machine oil in the compressor 12 can be further reduced.

  Even if the distance between the compressor 12 and the evaporator 9 when the compressor 12 is disposed above the evaporator 9 due to the above-described effect by the combination of isobutane, mineral oil, and the internal low-pressure compressor, for example, As in the present embodiment, the compressor 12 is arranged on a part of the top surface of the refrigerator main body 1, the evaporator is arranged near the lower part of the refrigerator main body 1, and the refrigerant returns from the evaporator 9 to the compressor 12. Even when the rising distance of the path becomes large, the reliability of the refrigerator can be sufficiently ensured.

  As a result, when a plurality of storage chambers having different temperature bodies are provided in the refrigerator main body 1, the evaporator 9 can be provided in a storage chamber other than the uppermost storage chamber, and the temperature becomes high during operation of the compressor 12. By moving the evaporator 9 away from the compressor 12, the condenser 16, etc., the cooling loss of the evaporator 9 due to the effect of exhaust heat from the high temperature part can be reduced, and the refrigeration capacity of the evaporator 9 can be utilized to the maximum, so that power consumption The amount can be reduced.

(Embodiment 2)
3, 4 and 5 show schematic views of the refrigerator in the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the same structure as Embodiment 1. FIG.

  As in the above-described embodiment, as the refrigerant, for example, isobutane is used as the hydrocarbon-based refrigerant, and the refrigerating machine oil is filled with mineral oil that is compatible with isobutane.

  In FIG. 3, a bending portion 21 is provided in a suction line 20 that connects the compressor 12 and the evaporator 9. When the bending angle of the bending portion 21 is θ degrees with respect to the vertically upward direction, the influence of the gravity component of the refrigerating machine oil facing the refrigerant flow direction returning from the evaporator 9 in the suction line 20 to the compressor 12 is COSθ. Since it is reduced by the multiplied amount, the refrigeration oil can be returned from the evaporator 9 to the compressor 12 more quickly.

  Further, in order to increase the enthalpy of the refrigerant in the evaporator 9 in the refrigeration cycle 18, the suction line 20 and the capillary 19 are in contact with each other at a predetermined distance by, for example, solder or the like, and the heat exchange is performed. Since it is possible to increase the distance of the suction line 20, it is easy to increase the heat exchange distance with the capillary 19, the refrigeration capacity of the evaporator 9 is increased, and the power consumption can be reduced.

  As shown in FIG. 4, if the suction line 20 is provided with a plurality of bent portions 21 and the suction line 20 meanders toward the compressor 12, the bending angle θ can be further reduced, so that it can be made more quickly. Refrigerating machine oil can be returned from the evaporator 9 to the compressor 12.

  Further, since the distance of the suction line 20 can be further increased, the heat exchange distance with the capillary 19 can be further increased, the refrigeration capacity of the evaporator 9 can be increased, and the power consumption can be reduced.

  In addition, as shown in FIG. 5, if the trap part 22 which bent a part of pipe | tube into the U shape, S shape, etc. was provided in the suction line 20 vertically downward, the refrigerating machine oil which flowed in the suction line 20 will be a bending part. Since it falls vertically downward at 21, the flow velocity of the refrigerating machine oil increases due to the influence of the gravitational acceleration. After that, since the inside of the suction line 20 is started up again to the compressor 12 through the trap portion 22 in a state where the flow rate is increased, the refrigerating machine oil can be more reliably returned from the evaporator 9 to the compressor 12.

(Embodiment 3)
FIG. 6 shows a schematic diagram of the refrigerator in the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the same structure as Embodiment 1. FIG.

  As in the above-described embodiment, as the refrigerant, for example, isobutane is used as the hydrocarbon-based refrigerant, and the refrigerating machine oil is filled with mineral oil that is compatible with isobutane.

  The refrigerator body 1 is provided with a refrigerating chamber 2 that is a relatively high temperature compartment in the upper portion and a freezer compartment 4 that is a relatively low temperature compartment in the lower portion. A refrigerating room cooling evaporator 23 that cools the refrigerating room 2 is provided, and a freezing room cooling evaporator 24 that cools the freezing room 4 is disposed, for example, on the back side in the freezing room 4. In the refrigeration cycle 18, the refrigerator for cooling the refrigerator compartment 23 is disposed upstream of the evaporator 24 for cooling the refrigerator compartment, and the outlet of the evaporator 23 for refrigerator cooling and the evaporator for cooling the refrigerator compartment are disposed. 24 inlet portions are connected by a joint pipe 25.

  By cooling each storage room with a dedicated evaporator, the odor transfer between the storage rooms is prevented, and the efficiency of the compressor 12 is improved due to the higher evaporation temperature of the evaporator 23 for cooling room cooling. Although it is possible to reduce and further increase the humidity in the refrigerator compartment 2, the piping volume of the evaporator increases, so that the amount of refrigerating machine oil that accumulates in the evaporator also increases. In the case where it is disposed above the refrigerator, there is a risk that the refrigerating machine oil in the compressor 12 is insufficient.

  Refrigerator oil is provided in the refrigerator main body 1 by disposing the evaporator 23 for cooling the refrigerator in the refrigeration cycle 18 upstream from the evaporator 24 for the refrigerator in the downstream of the refrigeration cycle 18. Can be sent from the refrigerating room cooling evaporator 23 to the freezing room cooling evaporator 24 without reversing in the direction of gravity, so that the refrigerating machine oil can be quickly returned to the compressor 12.

  In addition to the above configuration, the joint pipe 25 is not provided with a trap portion, and the straight pipe and the bending angle θ2 are set to 90 degrees or more and 180 degrees or less, so that the refrigerant is discharged from the compressor 12 into the refrigeration cycle 18 and cooled in the refrigerator. The refrigerating machine oil staying at the outlet portion of the evaporator 23 can be quickly sent to the freezer compartment cooling evaporator 24.

  As a result, the amount of refrigerating machine oil staying in the evaporator 23 for refrigerating room cooling can be minimized, further reducing the risk of damage to the compressor 12 due to a shortage of refrigerating machine oil in the compressor 12. it can.

  In this embodiment, the uppermost storage chamber is the refrigeration chamber 2, but the freezer cooling evaporator 24 is refrigerated in the refrigeration cycle 18 even in a top freezer type refrigerator having the freezer compartment 4 as the uppermost stage. A similar effect can be obtained by providing the upstream side of the room cooling evaporator 23 and not providing a trap portion in the connecting pipe between the freezer cooling evaporator 24 and the refrigerator cooling air evaporator 23.

  Further, if the refrigerator for cooling refrigerator 23 and the evaporator for cooling freezer 24 are configured to have a piping structure in which the refrigerant flows from the upper side to the lower side without a rising part in the path from the inlet part to the outlet part, Since the effect of the gravity of the refrigerating machine oil facing the refrigerant flow is eliminated, the flow speed of the refrigerating machine oil increases, and the refrigerating machine oil staying in each evaporator can be returned to the compressor 12 more quickly.

(Embodiment 4)
FIG. 7 shows a schematic diagram of the refrigerator in the fourth embodiment of the present invention, and FIG. 8 is a schematic diagram of a piping configuration in the same embodiment. In addition, the same code | symbol is attached | subjected about the same structure as background art.

  7 and 8, the refrigerator main body 100 injects a foam insulator 103 into a space formed by an inner box 101 obtained by vacuum molding a resin body such as ABS and an outer box 102 using a metal material such as a pre-coated steel plate. It has a heat insulation wall. As the heat insulator 103, for example, a hard urethane foam, a phenol foam, a styrene foam, or the like is used. Use of hydrocarbon-based cyclopentane as the foaming material is better from the viewpoint of preventing global warming.

  The refrigerator main body 100 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 104, a drawer-type vegetable compartment 105, and a drawer-type freezer compartment 106. Each heat insulation section is provided with a heat insulation door via a gasket 109. From the top, the refrigerator door 110, the vegetable compartment drawer door 111, and the freezer compartment drawer door 112 are shown. The refrigerating compartment revolving door 110 is provided with a door pocket 111 as a storage space, and a plurality of storage shelves 113 are provided in the cabinet. A storage case 114 is provided at the bottom of the refrigerator compartment 104.

  Further, the refrigerator main body 100 is provided with a first top surface portion 115 and a second top surface portion 116 having a recessed lower portion, and constitutes a machine room 117.

  The refrigeration cycle includes a compressor 118 elastically supported on the second top surface portion 116, a machine room fan 119 provided in the vicinity of the compressor 118, a condenser 120 provided at the lower portion of the refrigerator main body 100, and a condenser. 120, a condenser fan 121 provided near 120, a capillary 122 serving as a pressure reducer, a dryer (not shown) for removing moisture, and a cooling fan 123 arranged near the back of the vegetable compartment 105 and the freezing compartment 106. The provided evaporator 124 and the suction pipe 125 are connected in a ring shape.

  Further, a hydrocarbon-based refrigerant such as isobutane is used as the refrigerant, and a mineral oil compatible with isobutane is enclosed in the compressor 118.

  The machine room 117 is provided with a machine room cover 126 fixed with screws or the like at a position higher than the first top surface part 116, and houses the compressor 118, the machine room fan 119, and the like. An opening (not shown) that communicates with the upper portion of the first top surface portion 116 is provided in the machine room cover 126 using the difference in height between the top surface and the cover portion to constitute a heat radiation air passage.

  After discharging from the compressor 118, the piping configuration is arranged on the side panel so that heat exchange is possible with aluminum tape or the like, and is connected to the condenser 120 at the bottom. Further, after leaving the condenser 120, it passes around the front face of the opening of the refrigerator main body 100, is disposed on the opposite side surface, returns to the machine room 117, and is connected to the capillary 122 via a dryer (not shown).

  The capillary 122 and the suction pipe 125 are copper pipes having substantially the same length, and are soldered so that heat exchange is possible at the center part with the end part remaining. The capillary 122 uses a thin copper tube having a large internal flow resistance for pressure reduction, and the inner diameter is about 0.6 mm to 1.0 mm in combination with the length to adjust the pressure reduction amount. The suction pipe 125 uses a large-diameter copper pipe to reduce pressure loss, and its outer diameter is designed at a low cost with a standard pipe size of 6.35 mm to 7.94 mm. .

  Further, in order to ensure the length of the heat exchange unit, the meandering unit is compacted and compactly arranged so that the meandering unit comes to the back of the refrigerator compartment 104 so as not to contact between the inner box 101 and the outer box 102. Arranged and embedded in the thermal insulator 103. One end of the capillary 122 and the suction pipe 125 protrudes from the rear position of the vegetable chamber 105 of the inner box 101 and is connected to the evaporator 124, and the other end protrudes into the machine chamber 117 and the compressor 118, etc. Connected with.

  In addition, the cool air is distributed by an air passage 128 provided with a damper 127 that distributes the cool air cooled by the evaporator 124 to adjust the temperature.

  Further, a defrost heater 129 is provided below the evaporator 124, and a drain 130 for receiving defrost water and discharging it to the outside is provided below the defrost heater 129. An evaporating dish 131 is provided outside the refrigerator main body 100 and below the drain 130 to collect drainage during defrosting.

  The evaporating dish 131 is disposed behind the condenser 120, and the high-temperature air that has passed through the condenser 120 by the condenser fan 121 passes through the surface of the evaporating dish 131, so that the defrosted water can be dried.

  The temperature setting of each room is normally set at 1 to 5 ° C. with the lower limit of the temperature at which the refrigerator compartment 104 is not frozen for refrigerated storage, and the storage case 114 is relatively low for improving the freshness of meat fish and the like. The temperature is set at, for example, -3 to 0 ° C. Since the storage case is disposed below the refrigerator compartment 104, it is easy to make the temperature lower than that of the refrigerator compartment 104 by adjusting the amount of cooling with the opening area of the cooling air passage, and no dedicated damper is used. Sometimes.

  The vegetable room 105 is often set to a temperature setting of 2 ° C. to 7 ° C. that is the same as or slightly higher than that of the refrigerator room 104. It is possible to maintain the freshness of leafy vegetables for a long period of time as the temperature is lowered so as not to freeze. Moreover, the vegetable compartment 105 adjusts the amount of cooling with the opening area of a cooling air path, and may not provide a dedicated damper.

  The freezer compartment 106 is normally set at −22 to −18 ° C. for frozen storage, but may be set at a low temperature of −30 or −25 ° C., for example, to improve the frozen storage state.

  The operation | movement and effect | action are demonstrated in the refrigerator comprised as mentioned above.

  Cooling operation is performed according to the set predetermined temperature.

  First, the high-temperature and high-pressure refrigerant discharged by the operation of the compressor 118 is disposed around the refrigerator main body 100 and the condenser 120 that is air-cooled by the condenser fan 121 with relatively low-temperature air below the refrigerator main body 100. The heat is dissipated by the piping and is condensed and liquefied to reach the capillary 122. Thereafter, the pressure is reduced by the capillary 122 while exchanging heat with the suction pipe 125, and the low-temperature and low-pressure refrigerant reaches the evaporator 124.

  Due to the operation of the cooling fan 123, the low-temperature cold air exchanged heat with the evaporator 124 having a low temperature is distributed from the discharge port (not shown) to each chamber by the cooling duct 128 and the damper 127 insulated from the inside of the refrigerator. Temperature adjustment is performed. The cool air discharged into the refrigerator is again guided to the evaporator 124 through a return air passage (not shown) and circulated.

  The refrigerant that has exchanged heat with the air in the cabinet by the evaporator 124 is then sucked into the compressor 118 through the suction pipe 125. At this time, the refrigerating machine oil for ensuring the lubricity of the sliding portion of the compressor enclosed in the compressor 118 is compatible with the refrigerant and circulates in the piping. In order to improve the circulation of the refrigerating machine oil, it is important to ensure the circulation of the refrigerating machine oil. However, by using isobutane as the refrigerant, the gas flow rate in the pipe during operation is increased to circulate the refrigerating machine oil. Can be improved. Further, by using a compatible mineral oil, the circulation of the refrigerating machine oil is improved even in a liquid refrigerant or a two-phase refrigerant due to a phase change.

  Furthermore, by disposing the condenser 120 at a location away from the compressor 118, it is not affected by the heat of the compressor 118 that becomes high temperature, so that the pipe length can be reduced and the size can be reduced. Further, by disposing the condenser 120 on the bottom surface away from the compressor 118, heat exchange with relatively low-temperature air can be achieved, and further miniaturization becomes possible. This is because there is usually temperature variation in the refrigerator installation space, and the closer to the ceiling, the higher the temperature. Moreover, this temperature difference is more prominent in recent highly airtight houses. Further, in a kitchen environment where a refrigerator is usually installed, a more remarkable temperature difference is generated due to the influence of cooking equipment.

  Further, in the so-called bottom freezer type refrigerator in which the freezer compartment 106 is arranged at the lower part of the refrigerator main body 100 as in the present embodiment, the bottom surface temperature due to heat conduction is used in order to make the freezer compartment 106 and the condenser 120 adjacent to each other. The condenser 120 can be downsized even from the drop.

  By reducing the pipe length of the condenser 120, the amount of liquid refrigerant in the high-pressure pipe can be reduced, so the amount of refrigeration oil mixed with the liquid refrigerant in the high-pressure pipe can be reduced, and the circulation of the refrigeration oil can be improved. Can do.

  In addition, although the above-mentioned content was described in the viewpoint of the improvement of the circulation property of refrigerating machine oil by reducing the absolute amount of stagnant refrigerating machine oil by downsizing the condenser 120, the main condenser 120 is installed especially on the bottom surface of the refrigerator main body 100. If it is placed lower than the evaporator 124 and the length of other condensing pipes (for example, pipes for preventing dew condensation on the outer wall of the refrigerator body) is long and a lot of rising pipes are used, Under some conditions, the amount of liquid refrigerant increases and the viscosity of mixed refrigeration oil increases, which may lead to a decrease in circulation. Even when such conditions overlap, hydrocarbon-based isobutane is used as the refrigerant. Therefore, it is possible to greatly increase the flow velocity in the pipe during operation, and to ensure the circulation of the refrigeration oil, which is a mineral oil that mixes with the refrigerant in accordance with the increase in the flow velocity. It is what it is.

  Although the three-door layout has been described this time, the same effect can be obtained even with a multi-door type such as a 4-door or 5-door.

  In addition, the condenser 120 may be a fin coil, a spiral fin coil, a plate coil, or the like.

(Embodiment 5)
FIG. 9 shows a schematic diagram of the refrigerator in the fifth embodiment of the present invention, and FIG. 10 is a time chart in the same embodiment. In addition, the same code | symbol is attached | subjected about the same structure as background art.

  The compressor 132 uses a reciprocal inverter that is a variable exhaust capacity system whose interior is maintained at a low pressure. In addition to the reciprocating system that controls the number of revolutions with an inverter, the variable displacement system uses a compression system such as rotary and scroll, and a linear compression system that performs stroke control. The exhaust capacity control means 133 controls the exhaust capacity (cooling). Is controlled to change).

  As in the above-described embodiment, as the refrigerant, for example, isobutane is used as the hydrocarbon-based refrigerant, and the refrigerating machine oil is filled with mineral oil that is compatible with isobutane.

  In particular, in the low pressure vessel type inverter reciprocating system, the pressure inside the compressor 132 is low, so that the refrigerant is difficult to dissolve in the enclosed refrigeration oil, and the amount of refrigerant can be reduced, and the sliding part is not an oil seal depending on the rotational speed. It is efficient at low speed and has the most merit in terms of noise reduction and energy saving. Further, at the time of low rotation, since the discharge amount of the refrigerating machine oil can be reduced along with the reduction of the refrigerant circulation amount, the refrigerating machine oil in the compressor 132 can be prevented from decreasing.

  Each chamber is provided with internal temperature detection means 134 such as a thermistor, and the temperature is adjusted by the control means 135.

  In the time chart of FIG. 10, when the cooling operation is stable, the internal temperature detection means 134 such as a thermistor or an infrared sensor detects the internal temperature at a predetermined interval and transmits information to the control means 135.

  The control means 135 has an internal upper limit temperature setting (high) for starting the cooling operation and an internal lower limit temperature setting (low) for stopping the cooling, and the temperature rises exceeding the internal upper limit temperature setting with respect to the internal temperature. If you do. In addition, when the temperature falls below the lower limit temperature setting in the cabinet, the control unit 135 is controlled to stop the compressor 132.

  While the compressor 132 is stopped, the internal temperature rises, and the internal temperature detecting means 134 detects that the internal upper limit temperature setting is exceeded at (T1). Based on this signal, the control unit 135 operates the compressor 132. The exhaust capacity control means 133 is an exhaust volume control with variable frequency by an inverter, that is, a variable control of the refrigerating capacity, and operates the compressor 132 at the lowest possible rotational speed for energy saving.

  The exhaust capacity control means 133 first starts the operation of the compressor 132 at a low rotational speed, and changes the rotational speed at a predetermined timing. The change timing of the rotation speed has a predetermined temperature range in the range of the upper limit temperature setting and the lower limit temperature setting, for example, and it can be operated at the operation rotation speed according to each temperature range, or the operation rotation according to the temperature change amount There are methods such as setting the number. In either case, the number of revolutions is increased or decreased in order to estimate a state where the load is large and the refrigeration capacity is excessive or insufficient and to match the refrigeration capacity.

  At (T1), the count of the first timer 136a provided in the control means 135 is started. The first timer 136a counts during operation of the compressor 132, and stops counting when the compressor 132 stops. At (T2), the first timer 136a informs the control means 135 by a count-up signal that the predetermined time has elapsed. Based on this signal, the control means 135 forces the exhaust capacity control means 133 to increase the rotational speed. Further, counting of the second timer 136b is started, and a count-up signal is transmitted to the control means 135 when integration of a predetermined time determined separately has elapsed (T3). At (T3), the exhaust capacity control means 133 returns the rotational speed of the compressor 132 that has been forcibly increased to the original state, and returns to the normal control. With the operation of the compressor 132, the internal temperature decreases, the internal temperature detection means 134 detects that the internal temperature decreases beyond the internal lower limit temperature setting (T 4), and the control means 135 detects the compressor 132. Stop.

  With the compressor 132 stopped, the internal temperature gradually rises, and the internal temperature detection means 134 detects that the internal upper limit temperature setting is exceeded again (T5).

  By repeating the above operation, the internal temperature is adjusted to a predetermined temperature. Further, the temperature of each chamber may be adjusted by adjusting the amount of cold air by the operation of the damper 127 according to the temperature detection means.

  As described above, by using the variable displacement compressor 132, it is possible to achieve both low rotation of the compressor 132, energy saving by rank down, and securing of the compressor refrigerating oil circulation amount.

  Further, if the first timer 136a and the second timer 136b are combined, it can be rationalized.

  The above-mentioned viewpoint is intended to reduce the amount of refrigeration oil brought out from the compressor 132 by reducing the refrigerant discharge amount by the exhaust amount reduction control of the compressor 132. However, when the refrigerant pipe length of the refrigeration cycle is long or the pipe When the start of the compressor 132 is frequently used, under the conditions such as when the outside air temperature decreases and the liquid refrigerant increases or the viscosity of the refrigeration oil increases, such as in winter, the operation of the compressor 132 with the displacement reduction control is performed. If the refrigerant flow rate is not taken into consideration, there may be a case where the returnability of the refrigerating machine oil partially taken out from the compressor 132 is reduced as the refrigerant circulation amount is reduced.

  In contrast, in the present embodiment, as described above, isobutane, which is a hydrocarbon-based refrigerant, is used as the refrigerant, so that even under low displacement conditions, the compressor 132 discharges from the conventional case. It is possible to secure a sufficient flow velocity in the pipe for the refrigerating machine oil to return to the compressor 132 and increase the solubility of the refrigerant in the refrigerating machine oil, so that the refrigerant melts into the refrigerating machine oil, so that the viscosity of the refrigerating machine oil is increased. , And the amount of refrigerating machine oil returned from the evaporator 124 to the compressor 132 can be further increased.

  In other words, for cases where it is necessary to improve the return performance of refrigeration oil discharged together with the refrigerant during the refrigeration cycle with low displacement control depending on the conditions, mineral oil compatible with the refrigerant flow rate enhancement by refrigerant hydrocarbonation The use of is effective.

  As described above, when low displacement control of the compressor 132 is performed, the effect of reducing the take-out of refrigeration oil accompanying refrigerant discharge and the effect of a decrease in the returnability of the refrigeration oil after take-out coexist in some conditions. However, as a means to solve both of these problems at the same time, in addition to the combined use of mineral oil that is compatible with hydrocarbon hydrocarbons, the application of the low-pressure compressor 132 in a sealed container is an effective means. obtain.

  That is, first, the inside of the sealed container of the compressor 132 is made a low pressure type, and the low exhaust amount control is performed to reduce the amount of refrigeration oil taken out due to the refrigerant discharge from the compressor 132, and part of the refrigeration cycle taken out For the refrigerating machine oil, the return to the compressor 132 is improved by using a mineral oil that is compatible with the refrigerant flow rate enhancement by the hydrocarbonization of the refrigerant. Thereby, the quantity of the refrigerating machine oil discharged from the compressor 132 can be reduced, and dangers, such as damage of the compressor 132 by the refrigerating machine oil shortage in the compressor 132, can further be reduced.

(Embodiment 6)
FIG. 11 shows a time chart in the sixth embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the same structure as background art.

  As in the above-described embodiment, as the refrigerant, for example, isobutane is used as the hydrocarbon-based refrigerant, and the refrigerating machine oil is filled with mineral oil that is compatible with isobutane.

  When the internal temperature detection means 134 detects the internal temperature upper limit setting (T1), the count of the first timer 136a provided in the control means 135 is started. The exhaust capacity control means 133 starts operation with the operation speed of the inverter compressor 132 as the maximum speed. The first timer 136a counts for a predetermined time set in advance (T2), and the first timer 136a transmits the count-up signal to the control means 135. Based on this signal, the control means 135 causes the exhaust capacity control means 133 to reduce the rotational speed to normal operation control. The internal temperature detection means detects the preset temperature (T3, T4), and controls the rotational speed of the compressor 132 to achieve both energy saving and cooling capacity. When the internal temperature detection means 134 detects the internal temperature setting lower limit (T5), the compressor 132 is stopped by the control means 135. The internal temperature detection means 134 detects that the internal temperature rises and exceeds the internal upper limit temperature setting again (T6).

  The internal temperature is adjusted by repeating the above operation. As a result, since the compressor 132 is started at a high rotational speed, the amount of discharged oil is maximized due to the refrigerating machine oil blending into the stopped refrigerant, and the refrigerant flow rate in the pipe is assured at the start of sliding where the lubrication conditions are worst. By ensuring this, it is possible to ensure the circulation of the refrigerating machine oil. Furthermore, since the refrigerating machine oil stays in the evaporator 124 while being dissolved in the refrigerant during the stop, more refrigerating machine oil can be returned to the compressor 132 by securing the refrigerant flow rate in the pipe at the time of startup.

  In addition, although the refrigerating machine oil is reliably circulated by using the maximum exhaust capacity, the same effect can be obtained if the rotation speed is 50 rps or more which is the power supply frequency.

  As described above, the refrigerator according to the present invention can improve the returnability of the refrigerating machine oil to the compressor when it has a refrigerating cycle in which the compressor is disposed above the evaporator, so that the refrigerating machine oil in the compressor is insufficient. This is useful as a refrigeration cycle configuration of a storage unit equipped with a refrigerator for business use, a vending machine, and other cooling devices as well as a refrigerator for home use.

Sectional drawing of the refrigerator in Embodiment 1 of this invention Solubility curve diagram of refrigerant of refrigerator and refrigerating machine oil in Embodiment 1 of the present invention The front view seen from the back of the refrigerator in Embodiment 2 of this invention The front view seen from the back of the refrigerator in Embodiment 2 of this invention The front view seen from the back of the refrigerator in Embodiment 2 of this invention Sectional drawing seen from the back surface of the refrigerator in Embodiment 3 of this invention Sectional drawing of the refrigerator in Embodiment 4 of this invention Piping configuration diagram of refrigerator in embodiment 4 of the present invention Sectional drawing of the refrigerator in Embodiment 5 of this invention Time chart in Embodiment 5 of the present invention Time chart in Embodiment 6 of the present invention Cross-sectional view of a conventional refrigerator

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Refrigerator body 2,104 Refrigeration room 4,106 Freezer room 9,124 Evaporator 11,117 Machine room 12,118 Compressor 13,115 First top surface part 14 Back surface of refrigerator outer box 15,116 Second ceiling Face part 16,120 Condenser 17 Machine room cover 18 Refrigeration cycle 19,122 Capillary 20 Suction line 21 Bending part 22 Trap part 23 Refrigerating room cooling evaporator 24 Freezing room cooling evaporator 25 Joint piping 105 Vegetable room 119 Machine room fan 121 Condenser fan 123 Cooling fan 126 Machine room cover 132 Exhaust capacity variable type compressor (compressor)
133 Exhaust capacity control means 134 Internal temperature detection means 135 Control means 136a First timer 136b Second timer

Claims (7)

  A refrigeration cycle in which a compressor, a condenser, a decompressor, and an evaporator are provided in order to form a series of refrigerant flow paths; and a control means having an exhaust capacity control means for changing the exhaust capacity of the compressor. The compressor is disposed above the evaporator, and the refrigeration cycle is filled with hydrocarbons as refrigerant and mineral oil as refrigeration oil, and the displacement of the compressor is variable by the exhaust capacity control means. refrigerator.   A control means having an exhaust capacity control means and an internal temperature detection means are provided, and the exhaust capacity of the compressor is controlled at a predetermined timing based on the detection information of the internal temperature detection means to increase the refrigerant circulation flow rate of the refrigeration cycle. The refrigerator according to claim 1, wherein the refrigerator is made.   3. The refrigerator according to claim 1, wherein the exhaust capacity control unit is forced to operate with a larger exhaust capacity than that during normal control for a predetermined time when the compressor is started.   The said compressor is a refrigerator as described in any one of Claim 1 to 3 arrange | positioned at a part of top | upper surface of a refrigerator main body.   The refrigerator according to any one of claims 1 to 4, wherein the condenser is disposed in a region away from the compressor.   The refrigerator according to claim 5, wherein the condenser is disposed at a lower part of the refrigerator body.   7. The compressor according to claim 1, wherein the compressor includes an airtight container, an electric element and a compression element provided in the airtight container, and an internal space of the airtight container is a low pressure side in the refrigeration cycle. The refrigerator described.

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