Refrigerator comprising cold air supply device including compressor

Abstract

A refrigerator comprising a composition containing lubricating oil with a high energy-saving rate is provided and, specifically, a refrigerator comprising, for a refrigerating machine, a composition containing refrigerating machine oil capable of saving energy is provided. Provided is the refrigerator comprising: an inner case for forming storage compartments; a main body including an outer case on the outside of the inner case; doors for opening / closing the storage compartments; and a cold air supply device for supplying cold air to the storage compartments, wherein the cold air supply device includes a compressor, the compressor including a composition containing lubricating oil and microparticles present in a polydispersed state, and the difference between D90 and D10 of the microparticles present in the polydispersed state being 30 nm or more.

Description

A refrigerator including a cold air supply device including a compressor

[0001] The present invention relates to a refrigerator comprising a composition containing an energy-saving lubricating oil, a composition containing a refrigeration oil, and a refrigeration compressor.

[0002] Patent document 1 describes a refrigerant compressor comprising a sealed container, an electric element housed within the sealed container, and a compression element housed within the sealed container, driven by the electric element, and having a sliding part to compress the refrigerant, wherein a refrigerant oil that lubricates the sliding part is stored within the sealed container, and the refrigerant oil is in which fullerene having a diameter of 100 pm to 10 nm is added and dissolved in an amount less than the saturated dissolution amount for the refrigerant oil, and the fullerene in the refrigerant oil is maintained in a uniformly dispersed state even when the refrigerant compressor is in a stopped state.

[0003] Patent Document 2 describes D of 2.0μm to 10.0μm. 50 and D of 4.0–14.0 90 / D 10 A working fluid for a refrigeration unit is described, comprising a refrigeration oil containing fluorine-containing resin particles and a refrigerant composition.

[0004] [Prior Art Literature]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Publication No. 7012269

[0007] [Patent Literature 2] Patent Publication No. 7227501

[0008] Refrigeration and HVAC systems account for an increasing proportion of global energy consumption, and countries around the world are tightening energy regulations in the refrigeration sector. To meet these regulations, the development of low-cost technologies with high energy efficiency is underway.

[0009] From the perspective of materials in refrigeration cycles, technological development aimed at energy conservation has centered on the development of materials with high thermal insulation properties and the structure of heat exchangers with high thermal conductivity. Within energy conservation, improvements to compressor oils for refrigeration cycles have primarily consisted of the development of new refrigerants aimed at viscosity adjustment, additive development, and improved thermal conductivity, while the development of next-generation refrigeration oils leading to technological innovation has not been achieved.

[0010] The present invention aims to provide a home appliance comprising a composition containing a lubricating oil with a high energy saving rate, and in particular, a refrigerator comprising a composition containing a refrigeration oil capable of saving energy for use in a refrigerator.

[0011] The refrigerator of the present invention, completed under the above purpose, is as follows.

[0012] A refrigerator is provided, comprising: an inner body forming a storage room according to one embodiment; an outer body on the outside of the inner body; a door configured to open and close the storage room; and a cold air supply device for supplying cold air to the storage room, wherein the cold air supply device includes a compressor, and the compressor includes a composition including a lubricating oil and fine particles existing in a polydispersed state, and the difference between D90 and D10 of the fine particles existing in the polydispersed state is 30 nm or more.

[0013] According to another embodiment, a refrigerator is provided in which the D90 of the fine particles in the polydispersed state (the particle diameter at which the ratio of particles with a particle diameter of D90 or less is 90% of the total volume of the fine particles) is 80 nm or more.

[0014] According to another embodiment, a refrigerator is provided in which, in the polydispersed state, the D10 of the fine particles (the particle diameter at which the ratio of particles with a particle diameter of D10 or less is 10 volume% of the total fine particles) is 30 nm or more, and the D90 of the fine particles is 1000 nm or less.

[0015] According to another embodiment, a refrigerator is provided in which the microparticle comprises an inorganic compound, an organic compound, an organic-inorganic composite, or a combination thereof.

[0016] According to another embodiment, a refrigerator is provided in which the inorganic compound comprises a metal oxide, a metal nitride, a metal nitrate, a metal carbide, a carbonate, a sulfate, a hydroxide, a metal-based filler, a glass-based filler, a carbon-based filler, or a combination thereof, and the metal contained in the inorganic compound is selected from elements belonging to groups 2 to 16 of the periodic table.

[0017] According to another embodiment, a refrigerator is provided in which the inorganic compound comprises a crystalline metal oxide, an amorphous metal oxide, or a combination thereof.

[0018] According to another embodiment, a cold nitride is provided in which the inorganic compound comprises one or more selected from the group consisting of titanium oxide, silicon dioxide, aluminum oxide, iron oxide, copper oxide, and aluminum nitride.

[0019] According to another embodiment, the organic compound comprises a polymer, and the polymer comprises a fluorine-based polymer, a refrigerator is provided.

[0020] According to another embodiment, a refrigerator is provided in which the microparticle comprises a modified microparticle, the modified microparticle further comprises a hydrophobic substituent introduced on the surface of the microparticle, and the hydrophobic substituent comprises a hydrocarbon group having 4 or more carbon atoms. According to another embodiment, a refrigerator is provided in which the microparticle content is 2 wt.% or less with respect to the total weight of the lubricating oil and the microparticle.

[0021] According to another embodiment, the composition further comprises a dispersant, said dispersant having a hydrophobic portion and a hydrophilic portion, said hydrophilic portion having a polar functional group, said polar functional group having a carbonyl group, a carboxyl group, an amine group or a combination thereof, and a refrigerator is provided.

[0022] According to another embodiment, a refrigerator is provided in which the dispersant comprises a low molecular weight dispersant, a high molecular weight dispersant, or a combination thereof, and the high molecular weight dispersant comprises a modified polymer containing a polar functional group.

[0023] According to another embodiment, a refrigerator is provided in which the dispersant content is 2 wt.% or less with respect to the total weight of the lubricating oil, fine particles, and dispersant. According to another embodiment, a refrigerator is provided in which the lubricating oil is a refrigeration oil.

[0024] According to another embodiment, a refrigerator is provided in which the composition forms a phase distinct from the refrigerant.

[0025] According to one embodiment configured as described above, a refrigerator containing a composition capable of saving energy compared to a case containing fine particles existing in a monodispersed state can be provided.

[0026] According to one embodiment configured as described above, a refrigerator comprising a composition having a reduced friction coefficient when the composition is used as a lubricant compared to the case where the D90 of the fine particles present in the composition is small can be provided.

[0027] According to one embodiment configured in this way, a refrigerator comprising a composition with a reduced friction coefficient can be provided.

[0028] According to one embodiment configured as described above, a refrigerator comprising a composition capable of improving energy saving rate by reducing the friction coefficient can be provided.

[0029] According to one embodiment configured in this way, a refrigeration tank comprising a composition capable of saving energy can be provided.

[0030] According to the embodiment configured in this way, a refrigerator with improved energy saving rate can be provided.

[0031] FIG. 1 is a perspective view of a refrigerator according to one embodiment of the present disclosure.

[0032] FIG. 2 is a front view showing the interior of a refrigerator according to one embodiment of the present disclosure.

[0033] FIG. 3 is a cross-sectional view of a refrigerator according to one embodiment of the present disclosure.

[0034] FIG. 4 is a cross-sectional view of a compressor included in a refrigerator according to one embodiment of the present disclosure.

[0035] Figure 5a is a particle size distribution of fine particles in a fine particle dispersion oil, and is a particle size distribution in Example 1.

[0036] Figure 5b is a particle size distribution of fine particles in a fine particle dispersion oil, and is the particle size distribution in Comparative Example 2.

[0037] FIG. 6a is a schematic diagram of the condition of the fine particles in the composition of the present embodiment, and is a schematic diagram of the condition of the particles with a relatively small particle size among the fine particles (1).

[0038] FIG. 6b is a schematic diagram of the condition of the fine particles in the composition of the present embodiment, and is a schematic diagram of the shape of a relatively large particle among the fine particles (1).

[0039] Figure 7 is a graph showing the relationship between the dispersion particle diameters D10, D50, and D90 and the energy saving rate in Examples 1 to 12 and Comparative Example 2.

[0040] Various embodiments of the present disclosure and the terms used therein are not intended to limit the technical features described in the present disclosure to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0041] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0042] The singular form of the noun corresponding to the item may include one or multiple items, unless the relevant context clearly indicates otherwise.

[0043] In the present disclosure, each of the phrases such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, and “at least one of A, B, or C” may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0044] The term "and / or" includes a combination of multiple related described components or any of the multiple related described components.

[0045] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another component and do not limit the components in other aspects (e.g., importance or order).

[0046] Additionally, terms such as 'front,' 'rear,' 'top,' 'bottom,' 'side,' 'left,' 'right,' 'top,' and 'bottom' used in this disclosure are defined based on the drawings, and the shape and location of each component are not limited by these terms.

[0047] Terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this disclosure, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0048] When it is said that a component is "connected," "combined," "supported," or "in contact" with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0049] When it is said that a component is located "on" another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0050] In this disclosure, "size" of a particle refers to the "diameter" of a particle unless otherwise defined.

[0051] In the present disclosure, the “particle diameter” of a particle refers to the average diameter when the particle is spherical and the average major axis length when the particle is non-spherical. The particle diameter of a particle can be measured using a particle size analyzer (PSA). The “particle diameter” of a particle is, for example, the “average particle diameter.” The “average particle diameter” is, unless otherwise explicitly stated, the median particle diameter (D50). The median particle diameter (D50) is the particle size corresponding to the 50% cumulative value calculated from the side of the particle with the smallest particle size in a cumulative distribution curve of particle sizes in order from the smallest particle to the largest particle. The cumulative value may be, for example, a cumulative volume. The median particle diameter (D50) may be measured, for example, by laser diffraction. Alternatively, the “average particle diameter” may be measured by software or manually from a scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image.

[0052] In the present disclosure, "refrigerator" is a home appliance that supplies cold air generated by a compressor of a cold air supply device to a storage chamber to preserve various foods fresh for a long period of time.

[0053] A refrigerator may include, for example, a main body, and the main body may include an inner body and an outer body disposed on the outside of the inner body. The refrigerator may include, for example, an insulating material provided between the inner body and the outer body.

[0054] In the present disclosure, "inner body" is a member forming a storage chamber. The inner body may include, for example, a case, a plate, a panel, or a liner. The inner body may be formed, for example, as a single body or may be formed by assembling a plurality of plates.

[0055] In the present disclosure, "external body" is a member that forms the exterior of the main body. The external body may be coupled to the outer side of the internal body so that an insulating material is disposed between the internal body and the external body.

[0056] In the present disclosure, "storage room" is a space for storing items within a refrigerator. The storage room may include a space defined, for example, by an internal frame. The storage room may further include an internal frame defining a space corresponding to the storage room. Various items, such as food, medicine, and cosmetics, may be stored in the storage room, and the storage room may be formed so that at least one side is open for the retrieval and retrieval of items.

[0057] A refrigerator may include, for example, one or more storage compartments. When two or more storage compartments are formed in a refrigerator, each compartment may have a different purpose and may be maintained at a different temperature. To this end, each compartment may be partitioned from one another by a partition containing insulation.

[0058] The storage room may be configured to be maintained within an appropriate temperature range according to its intended use, for example, and may include a "refrigerated room," a "freezer room," and / or a "variable temperature room" distinguished according to its intended use and / or temperature range. The refrigerator room may be maintained at a temperature suitable for refrigerated storage of goods, for example. The freezer room may be maintained at a temperature suitable for frozen storage of goods, for example.

[0059] In the present disclosure, "refrigeration" means cooling an article to a temperature such that it does not freeze. For example, the refrigerator compartment may be maintained in a range from 0 degrees Celsius to 7 degrees Celsius.

[0060] In the present disclosure, “freezing” means freezing an article or cooling it to be maintained in a frozen state. For example, a freezer may be maintained in a range of -20 degrees Celsius to -1 degree Celsius.

[0061] The variable temperature compartment can be used as either a refrigerator or a freezer, with or without the user's choice.

[0062] Storage rooms may be referred to by various names, such as "vegetable room," "fresh room," "cooling room," and "ice-making room," in addition to terms like "refrigeration room," "freezer room," and "variable temperature room." The terms "refrigeration room," "freezer room," and "variable temperature room" used below should be understood as encompassing storage rooms with corresponding uses and temperature ranges.

[0063] The refrigerator may include at least one door configured to open and close one side of the storage compartment.

[0064] In the present disclosure, a “door” is a member configured to open and close each of one or more storage chambers, or configured such that a single door opens and closes multiple storage chambers. The door may be installed to be rotatable or sliding on the front of the main body.

[0065] The door may be configured to seal the storage room when the door is closed, for example. The door may include insulation material, similar to the main body, to insulate the storage room when the door is closed, for example.

[0066] The door may include, for example, an outer door panel forming the front of the door, an inner door panel forming the rear of the door and facing the storage room, an upper cap, a lower cap, and door insulation provided inside them.

[0067] A gasket may be provided on the edge of the door inner panel to seal the storage compartment by adhering to the front of the main body when the door is closed, for example. The door inner panel may include a dyke that protrudes rearward to allow for the installation of a door basket capable of storing items, for example.

[0068] The door may include, for example, a door body and a front panel detachably coupled to the front side of the door body and forming the front of the door. The door body may include, for example, an outer door panel forming the front of the door body, an inner door panel forming the rear of the door body and facing the storage room, an upper cap, a lower cap, and door insulation provided inside them.

[0069] Refrigerators can be classified, for example, into French Door Type, Side-by-side Type, BMF (Bottom Mounted Freezer), TMF (Top Mounted Freezer), or 1-door refrigerators depending on the arrangement of the door and storage compartment.

[0070] The refrigerator may include a cold air supply device provided to supply cold air to the storage compartment.

[0071] In the present disclosure, "cold air supply device" means a machine, apparatus, electronic device, and / or a system combining these that can generate cold air and guide cold air to cool a storage room.

[0072] A cold air supply device can generate cold air through a refrigeration cycle that includes the processes of compression, condensation, expansion, and evaporation of a refrigerant. To this end, the cold air supply device may include a compressor, a condenser, an expansion device, and an evaporator capable of driving the refrigeration cycle.

[0073] The refrigerator may include a machine room arranged to accommodate at least some parts belonging to the cold air supply unit.

[0074] In the present disclosure, "machine room" refers to a space in which at least some of the components belonging to a cold air supply device, etc. are placed. To prevent heat generated from the components placed in the machine room from being transferred to the storage room, it may be provided to be partitioned and insulated from the storage room. The interior of the machine room may be configured to communicate with the exterior of the main body to dissipate heat from the components placed inside the machine room.

[0075] The refrigerator may further include a dispenser provided on the door to provide water and / or ice. The dispenser may be provided on the door so that it is accessible to the user without opening the door.

[0076] The refrigerator may include an ice-making device configured to produce ice. The ice-making device may include an ice-making tray that stores water, an ice-removing device that separates ice from the ice-making tray, and an ice bucket that stores the ice produced in the ice-making tray.

[0077] It may include a processor for controlling the refrigerator.

[0078] In the present disclosure, the "processor" controls the overall operation of the refrigerator. The processor refers to a hardware device (chip) comprising an integrated circuit in which electrical circuits are integrated. The processor can control the components of the refrigerator by executing a program stored in memory. The processor may include a separate NPU that performs the operation of an artificial intelligence model. Additionally, the processor may include a central processing unit, a graphics-only processor (GPU), etc. The processor may generate a control signal to control the operation of a cold air supply device, for example. For example, the processor may receive temperature information of the storage compartment from a temperature sensor and generate a cooling control signal to control the operation of the cold air supply device based on the temperature information of the storage compartment.

[0079] The processor can process user input of the user interface and control the operation of the user interface according to programs and / or data stored in memory. The user interface may be provided using an input interface and an output interface. The processor can receive user input from the user interface. In response to the user input, the processor can transmit display control signals and image data to the user interface to display an image on the user interface.

[0080] In the present disclosure, "memory" stores or records various information, data, instructions, programs, etc., necessary for the operation of a refrigerator. Memory refers to a hardware device (chip) comprising an integrated circuit in which electrical circuits are integrated. Memory may store temporary data generated while generating control signals for controlling components included in the refrigerator. Memory may include at least one of volatile memory or non-volatile memory, or a combination thereof. The processor and memory may be provided integrally or separately. The processor may include one or more processors. For example, the processor may include a main processor and at least one sub-processor. Memory may include one or more memories.

[0081] For example, the refrigerator may include a processor and memory that control all the components included therein, and may include multiple processors and multiple memories that control these components individually. For example, the refrigerator may include a processor and memory that control the operation of a cold air supply device according to the output of a temperature sensor. The refrigerator may separately be equipped with a processor and memory that control the operation of a user interface according to user input.

[0082] In the present disclosure, "control unit" means a part comprising a memory that stores or remembers a program and / or data for controlling a refrigerator, and a processor that outputs a control signal for controlling a cold air supply device according to the program and / or data stored in the memory.

[0083] The communication module can communicate with external devices, such as servers, mobile devices, and other home appliances, through nearby Access Points (APs). The Access Point (AP) can connect the Local Area Network (LAN) to which the refrigerator or user device is connected to the Wide Area Network (WAN) to which the server is connected. The refrigerator or user device can be connected to the server through the Wide Area Network (WAN).

[0084] The input interface may include keys, touchscreens, microphones, etc. The input interface may receive user input and transmit it to the processor.

[0085] The output interface may include a display, a speaker, etc. The output interface can output various notifications, messages, information, etc. generated by the processor.

[0086] A refrigerator according to one embodiment of the present invention will be described below with reference to the drawings.

[0087] FIG. 1 is a perspective view of a refrigerator according to one embodiment of the present disclosure. FIG. 2 is a front view showing the interior of a refrigerator according to one embodiment of the present disclosure. FIG. 3 is a cross-sectional view of a refrigerator according to one embodiment of the present disclosure. FIG. 4 is a cross-sectional view of a compressor included in a refrigerator according to one embodiment of the present disclosure.

[0088] Referring to FIGS. 1 and 2, a refrigerator (1000) according to one embodiment of the present disclosure comprises a main body (1) having a storage compartment (2, 2a, 2b) and a door (3, 3a, 3b, 3c, 3d) coupled to the main body (1) to open and close the storage compartment. The main body (1) of the refrigerator (100) comprises an inner body; and an outer body disposed on the outside of the inner body. The refrigerator (1000) comprises a door (3, 3a, 3b, 3c, 3d) configured to open and close one side of the storage compartment (2). Although the refrigerator (1000) is depicted with four doors (3), the number of doors (3) is not limited thereto. The upper door (3a) and lower door (3b) on the right side of the refrigerator (1000) may be combined into a single door, and the upper door (3c) and lower door (3d) on the left side of the refrigerator (1000) may be combined into a single door. Additionally, the number of doors of the refrigerator (1000) may be more or fewer than four. Furthermore, the position of the doors (3) may be varied. Between the multiple doors (3a, 3b, 3c, 3d), there may be a handle area (4), which is a spaced-out area where a user can insert their hand to open and close the doors (3). The doors (3) may be configured to seal the storage compartment when the doors (3) are closed.

[0089] Referring to FIG. 3, a refrigerator (1000) according to one embodiment of the present disclosure comprises a main body (1) having a storage room (2) and a door (3) coupled to the main body (1) to open and close the storage room. The refrigerator (1000) comprises a cold air supply device (15) comprising a compressor (11), a condenser (not shown), an evaporator (12), and an expansion valve (not shown). Cold air generated from the evaporator (12) is supplied to the storage room (2) through a blower (13) so that the storage room (2) is maintained at a low temperature. The cold air supply device (15) comprises a compressor (11) that compresses a low-temperature, low-pressure gaseous refrigerant to a high-temperature, high-pressure temperature, a condenser (not shown) that releases heat from the refrigerant supplied from the compressor (11) to condense it into a liquid refrigerant, an expansion valve (not shown) that adiabatically expands the liquid refrigerant supplied from the condenser (not shown) to a low-temperature, low-pressure temperature, and an evaporator (12) that cools the surrounding air by absorbing the latent heat of vaporization of the refrigerant supplied from the expansion valve (not shown), thereby forming a refrigeration cycle connected sequentially by a cold air pipe to form a single cycle.

[0090] Referring to FIG. 4, a compressor (11) included in a refrigerator according to one embodiment of the present disclosure forms an exterior through a sealed container (30), and inside the sealed container (30) a driving unit (40) that provides a driving force for refrigerant compression and a compression unit (50) that receives the driving force from the driving unit (40) and performs the compression of the refrigerant are arranged. The driving unit (40) is provided as a conventional motor having a stator (43) fixed to the outer edge of a frame (41) and a rotor (44) rotatably installed inside the stator (43) to rotate through electromagnetic interaction with the stator (43). A terminal (31) is installed on one side of the sealed container (30) to apply power to the coil of the stator (43). The compression unit (50) includes a cylinder block (52) having a compression chamber (51) and a piston (53) installed inside the compression chamber (51) to enable linear reciprocating motion. The compression chamber (51) is sealed through a cylinder head (54) in which a refrigerant suction chamber (55) and a refrigerant discharge chamber (56) are partitioned inside, and the compression unit (50) may further be provided with a valve device (57) interposed between the cylinder head (54) and the cylinder block (52) to control the flow of refrigerant that is sucked into the compression chamber (51) through the refrigerant suction chamber (55) or discharged from the compression chamber (51) to the refrigerant discharge chamber (56).

[0091] The driving force of the driving unit (40) is transmitted to the compression unit (50) through the rotating shaft (60). One end of the rotating shaft (60) is pressed into the center of the rotor (44) so ​​as to rotate together with the rotor (44), and an eccentric shaft (61) is formed at the other end of the rotating shaft (60), and the eccentric shaft (61) and the piston (53) are connected through a connecting rod (62). When the rotating shaft (60) rotates together with the rotor (44) due to electromagnetic interaction between the stator (43) and the rotor (44), the eccentric rotational motion of the eccentric shaft (61) is converted into linear reciprocating motion of the piston (53) through the connecting rod (62), thereby performing the compression action of the refrigerant. A suction pipe (32) is connected to one side of the sealed container (30) to guide the refrigerant into the sealed container (30), and a discharge pipe (33) is connected to the other side of the sealed container (30) to guide the refrigerant that is compressed by the compression unit (50) and discharged outside the sealed container (30). The refrigerant guided by the suction pipe (32) and introduced into the sealed container (30) passes through the refrigerant suction chamber (55) of the cylinder head (54) and is sucked into the compression chamber (51) to be compressed. The refrigerant compressed in the compression chamber (51) is discharged to the refrigerant discharge chamber (56) of the cylinder head (54) and guided along the discharge pipe (33) toward the condenser (not shown) of the refrigeration cycle. A process pipe (34) used to fill oil or nitrogen gas into the sealed container (30) is installed on the other side of the sealed container (30).

[0092] A composition storage space (35) in which a predetermined amount of composition is stored is formed at the bottom of the sealed container (30), and a composition flow path (63) is formed in the rotating shaft (60) to guide the composition in the composition storage space (35) to be sprayed onto the upper part of the eccentric shaft (61) via the space between the rotating shaft (60) and the frame (41) by the centrifugal force of the rotating shaft (60). The composition includes lubricating oil and fine particles existing in a multi-dispersed state. The difference between D90 and D10 of the fine particles existing in a multi-dispersed state is 30 nm or more. The composition channel (63) includes a lower composition hole (64) formed on the lower inner side of the rotation shaft (60), a composition groove (65) formed spirally on the outer surface of the rotation shaft (60) corresponding to the hollow portion (42) of the frame (41) and formed so that the lower end communicates with the lower composition hole (64), and an upper composition hole (66) formed to extend from the upper end of the composition groove (65) through the interior of the rotation shaft (60) to the upper end of the eccentric shaft (61). A composition pickup member (67) is pressed into the lower end of the rotation shaft (60) to pick up the composition of the composition storage space (35) into the composition channel (63) using the centrifugal force resulting from the rotation of the rotation shaft (60), and a composition pickup wing (68) is installed inside the composition pickup member (67). Accordingly, when the rotating shaft (60) rotates due to the compression action of the refrigerant, the composition in the composition storage space (35) is transferred to the lower composition hole (64) via the composition pickup member (67) by the centrifugal force of the rotating shaft (60), and then supplied again to the composition groove (65) to lubricate the space between the rotating shaft (60) and the penetration part (42) of the frame (41), and the composition passing through the composition groove (65) is continuously guided to the upper part of the eccentric shaft (61) through the upper composition hole (66). A certain amount of the above composition is contained in the sealed container (30) for the lubrication and cooling of each part, and this composition is pumped to the upper part of the eccentric shaft (61) using the upward force generated when the rotating shaft (60) rotates, then scattered and sprayed toward the compression unit (50).

[0093] The composition sprayed onto the compression unit (50) is supplied to a cylinder block (52) having, for example, a compression chamber (51), and to a piston (53) installed to be capable of linear reciprocating motion inside the compression chamber (51). The composition supplied to the piston (53) inside the compression chamber (51) can reduce frictional resistance on the sliding surface between the linearly reciprocating piston (53) and the cylinder block (52). For example, a composition containing lubricating oil and fine particles existing in a multi-dispersed state can reduce the coefficient of friction between the linearly reciprocating piston (53) and the cylinder block (52), for example, static friction coefficient and dynamic friction coefficient.

[0094] As described above, the refrigerant passes through the compressor (11) via the suction pipe (32), the refrigerant suction chamber (55), the compression chamber (51), the refrigerant discharge chamber (56), and the discharge pipe (33). The composition supplied to the piston (53) is not supplied separately to the path through which the refrigerant travels. The composition may exist while forming a phase distinct from the refrigerant, and also forming a phase distinct from the wall surface of the cylinder block (52) constituting the compression chamber (51). Therefore, during the compression process of the compressor (11), the refrigerant may not be substantially mixed with the composition.

[0095] A relatively small number of particles among the fine particles included in the composition can flatten the sliding surface between the piston (53) and the cylinder block (52) by filling the fine grooves present on the surface of the piston (53). As a result, the friction coefficient between the piston (53) and the cylinder block (52) can be reduced. By reducing the friction coefficient between the piston (53) and the cylinder block (52), the compression efficiency of the compressor (11) can be improved.

[0096] Among the fine particles included in the composition, relatively large particles can be lodged between the piston (53) and the cylinder block (52), and the surface area can be reduced by the particles, thereby producing the same effect as a bearing. As a result, friction between the piston (53) and the cylinder block (52) can be reduced. The coefficient of friction between the piston (53) and the cylinder block (52) can be reduced. By reducing the coefficient of friction between the piston (53) and the cylinder block (52), the compression efficiency of the compressor (11) can be improved.

[0097] As the energy efficiency of the compressor (11) is improved, the cooling efficiency of the cold air supply device (15) can be improved. The power consumption of the refrigerator (1000) including the cold air supply device (15) can be reduced. Consequently, the energy efficiency of the refrigerator (1000) can be reduced.

[0098] <Composition of the composition according to the present embodiment>

[0099] Hereinafter, a composition applied to a refrigerator compressor according to an embodiment of the present invention will be described in detail. The embodiments described below are examples and do not limit the technical scope of the present invention to the following forms.

[0100] In the present invention, the description of "00 or more and 00 or less" or "00 to 00" indicating a numerical range means a numerical range including the upper and lower limits described, unless specifically mentioned otherwise.

[0101] The composition according to the present embodiment is a composition comprising a lubricating oil and fine particles existing in a polydispersed state.

[0102] There are no specific restrictions on the lubricant, and any commonly used lubricant may be used. Lubricants are broadly classified into industrial lubricants and automotive lubricants, and either of these can be used in the refrigerator of the present invention. Since industrial lubricants are suitable for applications utilizing a refrigeration cycle and are particularly suitable for refrigeration base oils, the refrigeration base oil will be described below in this embodiment.

[0103] Refrigeration oil is a lubricant for compressors used in refrigeration and air conditioning systems. Unlike other lubricants, it is characterized by direct contact with the refrigerant, which is responsible for the transfer of thermal energy within refrigeration and air conditioning equipment.

[0104] Cold air oils include, but are not limited to, mineral oil, hydrocarbon oil, ester oil, ether oil, or combinations thereof.

[0105] Specific refrigeration oils include, among general lubricating oils, paraffin-based or naphthenic-based mineral oil, alkylbenzene, polyalkyl glycol, polyol ester, polyvinyl alcohol, polyalphaolefin, etc. One or more selected from these are used.

[0106] Examples of refrigerant systems used with refrigeration oil include CFC, HCFC, HC, HFC, HFO, NH3, CO2, HF, etc.

[0107] Appropriate refrigeration oils and refrigerant systems should be selected and used. The combinations of general refrigeration oils and corresponding refrigerant systems are as follows, but there may be cases where refrigeration oils are unsuitable for specific refrigerants.

[0108] Refrigeration Oil: Suitable Refrigerant Systems

[0109] Mineral oil: CFC, HCFC, HC, NH3

[0110] Alkylbenzene: HCFC

[0111] Polyalkyl glycol: HCFC, HFC, HFO, CO2, NH3

[0112] Polyol esters: HFC, HFO

[0113] Polyvinyl alcohol: HFC, HFO

[0114] Polyalphaolefin: HFC, HFO, HF

[0115] For example, in the embodiments of the present application, a paraffinic mineral oil is used as the refrigeration oil, and HC is used in combination as the refrigerant.

[0116] In addition, the refrigerants specifically used are typically selected from those with a refrigerant number (Ashley number) starting with R. Particularly suitable refrigerants are listed below by refrigerant system.

[0117] HFC series: R134a, R23, R32, R404A, R407C, R407H, R410A, R448A, R449A

[0118] HFO series: R1234yf

[0119] HCFCs: R22

[0120] Others: R600a, R744, R290

[0121] The composition according to the present embodiment includes fine particles existing in a polydispersed state together with lubricating oil.

[0122] Particles are a general term for relatively small objects, and they vary in shape, density, etc. Fine particles specifically refer to those that are fine among particles, and objects of various sizes exist in nature. In this embodiment, "fine particles" refers to particles whose primary particle diameter in a solution is less than 1 μm, as measured by dynamic light scattering. Fine particles may be, for example, nanoparticles.

[0123] The present embodiment is characterized by the fact that fine particles exist in a polydispersed state in a liquid such as lubricating oil. By having the fine particles exist in a polydispersed state, the static coefficient of friction and the dynamic coefficient of friction of the entire composition are reduced, and it is possible to provide a composition capable of saving energy, particularly when used in a refrigeration unit. As a result, it is possible to provide a highly reliable refrigerant compressor and a refrigeration unit using the same using a conventional refrigeration cycle, and thus it can be widely applied to equipment and products such as refrigerators using a refrigeration cycle.

[0124] A polydisperse state is a state that contrasts with a monodisperse state, in which the particle diameters of the entire fine particles are not distributed and are nearly uniform. Even in a monodisperse state, theoretically, it is not a completely identical state. In this embodiment, a polydisperse state is defined as a state in which the difference between D10 and D90 is 30 nm or more, serving as an indicator for measuring the degree of dispersion of fine particles in a liquid.

[0125] The difference between D10 and D90 is determined by measurement using dynamic light scattering. First, the cumulative distribution function of the dispersion particle diameter distribution is obtained for the fine particles dispersed in the liquid, and D10, D50, and D90 are obtained from this cumulative distribution function. D10 is the particle diameter at which the proportion of particles with a diameter of D10 or less is 10 volume% of the total fine particles. D50 is the particle diameter at which the proportion of particles with a diameter of D50 or less is 50 volume% of the total fine particles, and is also called the median diameter. D90 is the particle diameter at which the proportion of particles with a diameter of D90 or less is 90 volume% of the total fine particles. The measured particle diameter is the diameter of the dispersion particles present in the composition. Therefore, the measured dispersion particle diameter cannot be viewed solely as the diameter of the primary particles, but may also be secondary or tertiary particles formed by the aggregation of primary particles. In some cases, particles with a smaller particle size distribution are measured as primary particles, and particles with larger sizes are measured as secondary and tertiary particles. When aggregated particles form a desirable particle size distribution, the diameter of the primary particles can be anything.

[0126] Figures 5a and 5b illustrate examples of particle size distributions when fine particles exist in a polydispersed state. The horizontal axis represents the diameter of the dispersed particles, and the vertical axis represents the frequency. Figure 5a is a particle size distribution of fine particles in the fine particle dispersion oil of Example 1, where the difference between D10 and D90 is 407 nm, which is a large example. Figure 5b is a particle size distribution of fine particles in the fine particle dispersion oil of Comparative Example 2, where the difference between D10 and D90 is 27 nm, which is a small example of a monodispersed state.

[0127] By having fine particles in a polydispersed state, the friction coefficient of the composition is reduced as described above, thereby improving the energy saving rate of the refrigeration equipment using the composition and achieving an energy saving effect. The mechanism thereof will be explained below.

[0128] In the case of the composition of the present embodiment, for example, refrigeration oil, friction between the cylinder and piston in the compressor of the refrigeration unit significantly affects the efficiency of the device. Meanwhile, since the fine particles exist in a highly dispersed state, the particle diameters of the fine particles are widely distributed. Fig. 6a illustrates a schematic diagram of the condition of the particles with relatively small particle diameters among the fine particles (100). As shown in Fig. 6a, the particles with relatively small particle diameters among the fine particles (100) are attached to the irregularities of the grooves (200) of the wall surface (200) of the cylinder or piston, and it is presumed that this smooths the surface and reduces the friction coefficient of the entire composition. Fig. 6b illustrates a schematic diagram of the shape of the particles with relatively large particle diameters among the fine particles (100). As shown in Fig. 6b, the particles with relatively large particle diameters among the fine particles (100) are stuck between the walls of the cylinder or piston, and it is presumed that the surface area is reduced by the particles and exerts the same effect as a bearing, thereby reducing friction. In this embodiment, as the cylinder or piston slides, the aggregated particles deagglomerate into primary particles and become smaller, resulting in a particle diameter suitable for smoothing the roughness of the sliding portion between the cylinder and the piston. In the case of relatively large particles in the shear layer being smoothed, the same effect as a bearing is achieved as described above. Consequently, the friction coefficient of the entire composition is reduced, and an energy saving effect is achieved.

[0129] In order to reduce the friction coefficient of the entire composition and enable energy saving when used as a refrigeration oil, the D90 of the composition, for example, the refrigeration oil, may be, for example, 80 nm or more, 100 nm or more, or 200 nm or more. The D10 of the refrigeration oil may be, for example, 30 nm or more, 40 nm or more, 50 nm or more, or 100 nm or more.

[0130] The combination of D10 and D90 as a range in which desirable fine particles are mainly distributed to reduce the friction coefficient of the entire composition and enable energy saving when used as a refrigeration oil may be, for example, D10 at 30 nm or more and D90 at 1000 nm or less, D10 at 40 nm or more and D90 at 590 nm or less, or D10 at 145 nm or more and D90 at 410 nm or less.

[0131] To achieve energy saving, the distribution of fine particles can be wide, and the difference between D10 and D90 can be 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, 90 nm or more, or 100 nm or more. When the difference between D10 and D90 is 100 nm or more, an energy saving rate of 2.5% or more can be easily achieved. Since D90 is unsuitable if it is too large, the difference between D10 and D90 can be 900 nm or less, 800 nm or less, 700 nm or less, 600 nm or less, or 500 nm or less.

[0132] The polydispersed distribution of particle diameters can be composed of, for example, fine particles of two or more types of materials. It can be prepared in a polydispersed state overall by using multiple particles in a monodispersed state.

[0133] The material of the fine particles in this embodiment is not particularly limited as long as it can maintain a desirable dispersed particle diameter in a polydispersed state in the refrigeration oil. For example, fine particles made of inorganic compounds, organic compounds, organic-inorganic composites, etc., can be appropriately selected and used as the material of the fine particles.

[0134] Examples of fine particles using inorganic compounds include fine particles made of metal oxides, metal nitrides, metal nitrates, metal carbides, carbonates, sulfates, hydroxides, metal-based fillers, glass-based fillers, carbon-based fillers, or combinations thereof. The metal contained in the above-described inorganic compound may be selected, for example, from elements belonging to groups 2 to 16 of the periodic table. The metal contained in the above-described inorganic compound may be, for example, titanium, silicon, aluminum, copper, iron, magnesium, etc. The metal contained in the above-described inorganic compound may be, for example, a transition metal.

[0135] Examples of fine particles using metal oxides include fine particles made of crystalline metal oxides, amorphous metal oxides, or combinations thereof. Crystalline metal oxides may include, for example, single-crystal metal oxides, polycrystalline metal oxides, or combinations thereof.

[0136] Examples of microparticles using inorganic compounds include microparticles made of materials such as metal oxides, carbonates, sulfates, hydroxides, metals, metal nanotubes, smectite, glass beads, talc, and carbon-based fillers.

[0137] Examples of microparticles using organic compounds include microparticles of polymer resins and microparticles of organic pigments. Microparticles using other inorganic-organic composite compounds are also possible. The polymer resin may be, for example, a fluorinated polymer resin. The polymer resin may be, for example, polytetrafluoroethylene (PTFE).

[0138] Examples of inorganic compounds used in specific fine particles may include metal oxides, and examples of specific inorganic compounds containing metal oxides include titanium oxide (TiO2), silicon dioxide (SiO2), aluminum oxide (Al2O3), iron oxide (Fe2O3), copper oxide (CuO), and aluminum nitride (AlN). The metal oxide may be, for example, titanium oxide.

[0139] In the case of titanium oxide, the crystal system may be either anatase or rutile, or it may be a mixed crystal system containing multiple different crystal phases. When using a metal oxide containing titanium oxide, the surface of the fine particles may be surface modified with hydrophobic substituents to improve the dispersibility of the fine particles. The hydrophobic substituents introduced to the surface of the fine particles may be, for example, hydrocarbon groups having 4 or more carbon atoms, 6 or more, or 8 or more carbon atoms. The hydrophobic substituents introduced to the surface of the fine particles may be, for example, hydrophobic alkyl groups such as isobutyl groups or octyl groups.

[0140] If there are too many fine particles in the composition, for example, refrigeration oil, the dispersibility may be poor. For example, the content of fine particles in the composition may be 5 mass% or less, 4 mass% or less, or 2 mass% or less. The content of fine particles in the composition is, for example, 0.1 mass% or more and 5 mass% or less, 0.5 mass% or more and 4 mass% or less, or 0.5 mass% or more and 2 mass% or less.

[0141] The composition according to the present embodiment preferably includes a dispersant to further improve the dispersibility of the fine particles. The dispersant may be a substance generally referred to as a surfactant or dispersant, having a substituent or molecular structure that has an affinity for both the refrigeration oil and the fine particles. That is, as in the present embodiment, when the fine particles have hydrophilicity such as metal oxides represented by titanium oxide, the dispersant may have a hydrophilic portion that has an affinity for the fine particles and a hydrophobic portion that has an affinity for the refrigeration oil.

[0142] The composition may include a dispersant, and the dispersant may include, for example, a low molecular weight dispersant, a high molecular weight dispersant, or a combination thereof. The low molecular weight dispersant may be a dispersant with a molecular weight of 1,000 daltons or less. The high molecular weight dispersant may be a dispersant with a molecular weight of 2,000 daltons or more.

[0143] When metal oxides such as titanium oxide are used as fine particles, examples of dispersants include low-molecular-weight compounds equivalent to monomers, such as compounds having polar groups such as carboxyl groups or amino groups on an alkyl group. Specific examples of compounds are given below.

[0144] Carvonoidal compounds such as oleic acid, stearic acid, and linoleic acid

[0145] Amino compounds such as oleylamine

[0146] Phosphoric acid compounds such as octadecylphosphonic acid

[0147] Phosphine oxide compounds such as trioctylphosphine oxide

[0148] Also, as a compound having polyethylene oxide in an aromatic alkyl group, for example, polyoxyethylene (10) octylphenyl ether.

[0149] Examples of dispersants when using metal oxides such as titanium oxide include polymers having polar groups such as carbonyl groups, carboxyl groups, and amino groups in the case of polymers.

[0150] As a dispersant, polymers with polar groups can be used rather than low-molecular-weight compounds.

[0151] The above polymer dispersant may include a modified polymer containing polar functional groups.

[0152] If the amount of dispersant in the composition, for example, refrigeration oil is excessive, the dispersibility may be poor. The content of the dispersant in the composition may be, for example, 5 mass% or less, 4 mass% or less, or 2 mass% or less. The content of the dispersant in the composition is, for example, 0.1 mass% or more, 0.5 mass% or more, or 2 mass% or less, or 0.5 mass% or more, or 1.0 mass% or less.

[0153] In the composition according to the present embodiment, at least one selected from the group consisting of load-bearing additives, chlorine capture agents, clean dispersants, viscosity index improvers, heat resistance improvers, stabilizers, chlorine capture agents, clean dispersants, corrosion inhibitors, flow viscosity enhancers, and the like may be added to the refrigeration oil as needed. In addition to or in addition to the other aforementioned additiveable substances, at least one selected from the group consisting of compatibilizers, ultraviolet fluorescent dyes, polymerization inhibitors, antioxidants, extreme pressure agents, acid capture agents, oxygen capture agents, copper inactivators, rust inhibitors, oily agents, and defoaming agents may be added.

[0154] The composition according to the present embodiment may form a phase distinct from the refrigerant. The composition forms a phase distinct from the refrigerant, and the composition may not mix with the refrigerant.

[0155] In the present embodiment, the method of adjusting the composition to form a phase distinct from the refrigerant is not particularly limited.

[0156] As a method for dispersing additives, such as fine particles and other dispersants, into the refrigeration oil as needed, conventional dispersion techniques such as mixing and stirring with a stirrer or agitator, disaggregation techniques using ultrasound, and bead mills using micro beads can be appropriately used.

[0157] An example of a method for adjusting a composition according to the present embodiment is described below in the order of (1), (2), etc.

[0158] (1) Preparation and weighing of raw materials: Prepare refrigeration oil, fine particles, and additives such as other dispersants as needed, and weigh the required amount.

[0159] (2) Preparation of refrigeration oil: When using a dispersant, add the dispersant to the refrigeration oil and dissolve it sufficiently.

[0160] (3) Fine particle filling: Fine particles are added to the refrigeration oil obtained in (2) and dispersed in the refrigeration oil to some extent, and then transferred to a reaction vessel equipped with a magnetic stirrer.

[0161] (4) Adding beads: For example, add stirring beads with a diameter of 50 micrometers to the reaction vessel of (3) at a volume of about 20% relative to the liquid amount of refrigeration oil.

[0162] (5) De-aggregation: The refrigeration oil with added beads is stirred at room temperature at a speed of, for example, 1000 revolutions / minute for a time suitable for the amount and materials used to de-aggregate the fine particles.

[0163] (6) Settling: Let the stirring beads settle completely, for example, for a few minutes.

[0164] (7) Separation and recovery: The refrigeration oil containing fine particles in a highly dispersed state is recovered from the reaction vessel by decanting to separate the stirring beads.

[0165] The present invention is not limited to the above embodiments, and other embodiments are possible within the spirit of the present invention.

[0166] For example, although the lubricant has been described mainly as refrigeration oil, it can also be used as other industrial lubricants such as bearing oil, turbine oil, and hydraulic operating oil, and as automotive lubricants such as engine oil, gear oil, and automatic transmission oil.

[0167] Embodiments of the invention are described in detail below by way of examples, but the embodiments of the invention are not limited to these examples in any way. Unless otherwise specifically stated in the following description, "%" is based on mass.

[0168] (Examples 1–12, Comparative Examples 1–2)

[0169] Preparation of Fine Particle Dispersion Oil

[0170] Using compressor base oil (FREOL S5P) for a refrigeration cycle as the refrigeration base oil, fine particles and a dispersant were blended into this compressor base oil for a refrigeration cycle in the following order to prepare a fine particle dispersion oil.

[0171] For the compressor base oil for the refrigeration cycle, an amount of fine particles and a dispersant equaling 1 mass% was measured and prepared. The particle type, crystal form, and primary particle diameter of the fine particles are listed in Table 1 or Table 2. The fine particles of Comparative Example 2 and Example 6 had surfaces modified with isobutyl groups, while other fine particles were used without modification. Additionally, the crystal forms of aluminum oxide, copper oxide, and aluminum nitride were unclear and were indicated as "-" in the table.

[0172] The dispersants used were the polymeric or low molecular weight dispersants described below. As indicated in Tables 1 and 2, the comparative example and example in Table 1 used a polymeric dispersant and were labeled "polymeric," while the example in Table 2 used a low molecular weight dispersant and were labeled "low molecular weight."

[0173] *Dispersant

[0174] · Polymer dispersant: Organically modified polymer having amino groups. Amine value of approximately 30 mgKOH / g.

[0175] · Low molecular weight dispersant: Trioctylphosphine oxide

[0176] A dispersant was added to the compressor base oil for the refrigeration cycle and sufficiently dissolved. Next, fine particles were added to the compressor base oil in which the dispersant was dissolved to disperse the particles to some extent, and then transferred to a glass container equipped with a magnetic stirrer. Zirconium oxide (ZrO2) beads with a diameter of 50 μm were added in an amount that accounted for approximately 20% of the volume of the compressor base oil, and the mixture was stirred at a speed of 1,000 revolutions per minute at room temperature for 360 minutes to disperse the fine particles within the compressor base oil.

[0177] After stirring, the oil was left to stand for a few minutes to allow the zirconium oxide beads to settle completely, and the supernatant was separated by decanting to obtain the fine particle dispersed oils of Examples 1 to 12 and Comparative Example 2. In addition, Comparative Example 1 did not use fine particles or a dispersant, and only compressor base oil for a refrigeration cycle (hereinafter abbreviated as "Base oil") was used as a control.

[0178] To determine the dispersion state of the particulates present in each particulate dispersion, D10, D50, and D90 were measured using a dynamic light scattering photometer (DLS-8000) manufactured by Otsuka Electronics Co., Ltd., and the measured values ​​are listed in Tables 1 and 2. The measurement conditions were a measurement angle of 90 degrees and a measurement temperature of 25 ℃, and D10, D50, and D90 were calculated using values ​​of refractive index 1.467, permittivity 2.2, and viscosity 6.3.

[0179] <Refrigerator Power Consumption Evaluation>

[0180] The evaluation method for the refrigerator's power consumption was conducted in accordance with the IEC 62552 standard. A built-in freezer (a refrigerator built into a built-in cabinet or shelf) manufactured by Samsung Electronics Co., Ltd., with product number RZ38B98C5AP, which is an R600a refrigeration unit, was used as the evaluation refrigerator.

[0181] For the first evaluation, the refrigerator was modified to be equipped with a temperature sensor and a refrigerant pressure gauge, and vacuum suction and refrigerant filling were continuously performed. Afterward, the power consumption was evaluated using the Base oil of Comparative Example 1. The timing of the first evaluation was set to 72 hours after the start of operation of the refrigerator.

[0182] After the first evaluation, refrigeration cycle cleaning was performed. This refrigeration cycle cleaning was carried out by first disconnecting the compressor, flowing a dedicated refrigeration cycle cleaning solution (manufactured by Asahi Kasei Co., Ltd., Product name: AMOLEA AS-300) through the connection of the freezer-side refrigeration cycle discharge pipe, and then discharging it through the connection of the freezer-side refrigeration cycle suction pipe. After refrigeration cycle cleaning, the cycle cleaning solution remaining in the refrigeration circuit was evaporated by vacuum suction using a vacuum pump.

[0183] Next, the oil accumulated inside the compressor was discharged at the process pipe connection. At this time, to sufficiently discharge the accumulated oil, fresh base oil was introduced from the process pipe several times to dilute and discharge the base oil accumulated inside the compressor.

[0184] After the cleaning process, the particulate dispersion oils of Examples 1 to 12 and Comparative Example 2 were replaced, and an evaluation was conducted under the same conditions as when measuring the base oil. For the evaluation of the particulate dispersion oils, stable data for 10 cycles was obtained for each particulate dispersion oil to calculate the annual power consumption, and the results were compared with the annual power consumption when using the base oil of Comparative Example 1.

[0185] The energy saving rate of annual power consumption was calculated using the following formula and is listed in Tables 1 and 2. In the tables, ▲ attached to the numbers of the energy saving rates indicates a minus sign.

[0186] [Formula 1]

[0187] Φ = (P n - P BASE ) / P BASE ×100

[0188] Here, the meaning of each character is as follows.

[0189] Φ: Energy saving rate (%),

[0190] P n : Annual power consumption (kWh / year) when using particulate dispersion oil

[0191] P BASE : Annual electricity consumption (kWh / year) when using base oil

[0192] Examples, Comparative Preliminary Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Energy Saving Rate (%) ▲0.5 ▲5.3 ▲3.5 ▲2.9 ▲2.6 ▲1.5 ▲1.5 Particles Type Titanium Oxide Titanium Oxide Titanium Oxide Titanium Oxide Titanium Oxide Titanium Oxide Crystalline Form Rutile-anatase + Rutile-rutile-rutile-anatase + Rutile-rutile-rutile Surface Modification Isobutyl Untreated Untreated Untreated Untreated Isobutyl Primary Particle Diameter (nm) 15 100 35 180 100 35 15 Dispersed Particle Diameter (nm) D 10 25 13 4 100 18 2 100 56 41 D 50 34 21 3 140 26 11 40 77 59 D 90 52 5 41 23 0 42 23 0 12 3 95 Dispersant Polymer Polymer Polymer Polymer Polymer Polymer Polymer

[0193] Examples Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Energy Saving Rate (%) ▲2.7 ▲1.6 ▲2.0 ▲0.8 ▲1.0 ▲1.3 Particle Type Titanium Oxide Titanium Oxide Titanium Oxide Aluminum Oxide Copper Oxide Aluminum Oxide Crystalline Form Anatase + Rutile Anatase + Rutile Anatase + Rutile --- Surface Modification Untreated Untreated Untreated Untreated Untreated Untreated Primary Particle Diameter (nm) 100 100 100 50 50 50 Dispersed Particle Diameter (nm) D 10 26 25 21 10 57 6 25 6 D 50 35 37 51 25 8 28 47 5 D 90 58 21 18 150 17 21 31 11 8 Dispersant Low Molecular Weight Low Molecular Weight Low Molecular Weight Low Molecular Weight Low Molecular Weight

[0194] Figure 7 shows a graph of the relationship between the energy saving rate and the dispersion particle diameters D10, D50, and D90 in Examples 1 to 12 and Comparative Example 2. In Figure 3, the horizontal axis represents the energy saving rate (more precisely, negative), and the vertical axis represents the dispersion particle diameter. As can be seen from Figure 7, the dispersion particle diameter and the energy saving rate are largely in a directly proportional relationship, and the larger the dispersion particle diameter, the greater the energy saving rate. The higher the degree of dispersion of the fine particles and the larger the difference between D10 and D90, the more significantly the energy saving rate increases. In addition, it was found that the energy saving rate is not affected by the type of fine particles, the crystal system, or the primary particle diameter.

[0195] Friction Test

[0196] A friction test was conducted on the base oil of Comparative Example 1 and the fine particle dispersion oil of Example 1.

[0197] The test was conducted using a friction wear tester "Tribogear" (TYPE: 40, manufactured by Shinto Kagaku Co., Ltd.) with a stainless steel SUS304 plate thoroughly cleaned with anhydrous ethanol and a ball indenter made of SUS304 with a diameter of 10 mm.

[0198] The static friction coefficient was measured by applying 10 drops (approx. 60 μL) of the oil to the sliding part of the stainless steel plate and starting the test. In addition, the dynamic friction coefficient was measured by sliding 50 times under each condition with a load of 500 g, a sliding speed of 800 mm / s, and a sliding distance of 10 mm, and under environmental conditions of a temperature of 25.5 ℃ and a humidity of 61%.

[0199] The results are recorded in Table 3.

[0200] Measurement Target Static Friction Coefficient Passive Friction Coefficient Comparison Example 1 Base Oil 0.38 20.354 Example 1 Fine Particle Dispersion Oil 0.18 10.169

[0201] It was confirmed that the friction coefficient of the fine particle dispersion oil becomes very small compared to the base oil in both static and dynamic friction coefficients.

[0202] According to one embodiment, a refrigerator containing a composition capable of saving energy compared to a case containing fine particles existing in a monodispersed state can be provided.

[0203] According to one embodiment, a refrigerator comprising a composition having a reduced friction coefficient when the composition is used as a lubricant compared to when the D90 of the fine particles present in the composition is small can be provided.

[0204] According to one embodiment, a refrigerator comprising a composition with a reduced friction coefficient can be provided.

[0205] According to one embodiment, a refrigerator comprising a composition capable of improving energy saving rate by reducing the friction coefficient can be provided.

[0206] According to one embodiment, a refrigeration tank comprising a composition capable of saving energy can be provided.

[0207] According to one embodiment, a refrigerator with improved energy saving rate can be provided.

Claims

1. An internal structure forming a storage chamber; A main body including an external external injury to the internal injury mentioned above; A door configured to open and close the above storage room; and It includes a cold air supply device that supplies cold air to the above storage room, The above cold air supply device includes a compressor, and the compressor A composition comprising a lubricating oil and fine particles existing in a polydispersed state, A refrigerator in which the difference between D90 and D10 of the fine particles existing in the above polydispersed state is 30 nm or more.

2. In Paragraph 1, A refrigerator in which the D90 of the fine particles in the above polydispersed state is 80 nm or more.

3. In Paragraph 1, A refrigerator in which, in the above polydispersed state, the D10 of the fine particles is 30 nm or more and the D90 of the fine particles is 1000 nm or less.

4. In Paragraph 1, The above-mentioned microparticles comprise an inorganic compound, an organic compound, an organic-inorganic composite, or a combination thereof, in a refrigerator.

5. In Paragraph 4, The above inorganic compound includes metal oxides, metal nitrides, metal nitrates, metal carbides, carbonates, sulfates, hydroxides, metal-based fillers, glass-based fillers, carbon-based fillers, or combinations thereof, and A refrigerator in which the metal contained in the above-mentioned inorganic compound is selected from elements belonging to groups 2 through 16 of the periodic table.

6. In Paragraph 4, The above-mentioned inorganic compound comprises a crystalline metal oxide, an amorphous metal oxide, or a combination thereof, in a refrigerator.

7. In Paragraph 4, A refrigerator comprising one or more inorganic compounds selected from the group consisting of titanium oxide, silicon dioxide, aluminum oxide, iron oxide, copper oxide, aluminum nitride, and talc.

8. In Paragraph 4, The above organic compound includes a polymer, A refrigerator in which the above polymer comprises a fluorine-based polymer.

9. In Paragraph 1, The above-mentioned microparticles include modified microparticles, The above-mentioned modified microparticle further comprises hydrophobic substituents introduced on the surface of the microparticle, and A refrigerator in which the above hydrophobic substituent comprises a hydrocarbon group having 4 or more carbon atoms.

10. In Paragraph 1, A refrigerator having a particulate content of 2 wt.% or less relative to the total weight of the lubricating oil and particulates.

11. In Paragraph 1, The above composition further comprises a dispersant, said dispersant having a hydrophobic portion and a hydrophilic portion, and The above hydrophilic portion includes a polar functional group, and A refrigerator in which the above polar functional group comprises a carbonyl group, a carboxyl group, an amino group, or a combination thereof.

12. In Paragraph 11, The above-mentioned dispersant includes a low molecular weight dispersant, a high molecular weight dispersant, or a combination thereof, A refrigerator comprising a modified polymer containing polar functional groups, wherein the above-mentioned polymer dispersant comprises a modified polymer.

13. In Paragraph 11, A refrigerator in which the dispersant content is 2 wt.% or less with respect to the total weight of the lubricating oil, fine particles, and dispersant.

14. In Paragraph 1, The above lubricating oil is a refrigeration oil, and A refrigerator in which the refrigeration oil comprises mineral oil, hydrocarbon oil, ester oil, ether oil, or a combination thereof.

15. In Paragraph 1, A refrigerator in which the above composition forms a phase distinct from the refrigerant.

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