refrigerator

Abstract

To provide a refrigerator capable of maintaining a heating heat quantity required to defrost even if outside air temperatures are different throughout the year, when utilizing the waste heat of the refrigerator for defrosting.SOLUTION: A refrigerator for utilizing the waste heat of a compressor for defrosting includes a vaporizer, heating means for heating the vaporizer to defrost, and heating control means for controlling a heating amount by the heating means according to outside air temperatures. Thus, the heating amount by the heating means can be controlled according to the outside air temperatures to make up for a heat quantity change in the condensation latent heat of cooling medium, therefore achieving a shorter defrosting time and energy saving regardless of a change of the outside air temperatures and the frosting state of the vaporizer.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to refrigerators. [Background technology]

[0002] Patent Document 1 discloses a refrigerator with defrosting capabilities. This refrigerator has a path connecting a compressor discharge port to a defrosting pipe disposed in an evaporator, and supplies high-temperature, high-pressure refrigerant discharged from the compressor to the defrosting pipe via a refrigerant flow path switching valve, and performs defrosting using the heat generated by a change in the state of the refrigerant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 58-024774 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a refrigerator that compensates for changes in the heat quantity of the latent heat of condensation of a refrigerant, and is capable of shortening defrosting time and saving energy regardless of changes in outside air temperature or the state of frost on the evaporator. [Means for solving the problem]

[0005] The refrigerator disclosed herein is a refrigerator that uses waste heat from a compressor for defrosting, and includes an evaporator, a heating means for heating the evaporator to defrost, and a heating control means for controlling the amount of heating by the heating means depending on the outside air temperature. [Effects of the Invention]

[0006] The refrigerator according to the present disclosure utilizes waste heat to defrost the first storage compartment, and can efficiently cool the second storage compartment by the heating-side evaporator. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a longitudinal sectional view of a refrigerator according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing the configuration of a first and second machine compartment of a refrigerator according to a first embodiment. [Figure 3] FIG. 1 is a perspective view of an evaporator of a refrigerator according to a first embodiment; [Figure 4] FIG. 1 is a diagram showing a configuration of a refrigeration cycle of a refrigerator according to a first embodiment. [Figure 5A] Mollier diagram of the refrigerator during cooling operation in the first embodiment [Figure 5B] Mollier diagram during defrosting operation of refrigerator in embodiment 1 [Figure 6] FIG. 10 is a diagram showing control during defrosting of a refrigerator according to the first embodiment. [Figure 7] Characteristics graph of outside temperature and heating capacity of refrigerator in embodiment 1 [Figure 8] FIG. 10 is a diagram showing control during defrosting of a refrigerator in a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Findings that formed the basis of this disclosure) Refrigerators are known that have a defrosting function that melts frost that has adhered to an evaporator. The defrosting function typically involves providing a defrost heater below the evaporator and energizing the defrost heater to melt the frost.

[0009] The refrigerator disclosed in Patent Document 1 is capable of utilizing the heat of the compressor for defrosting. The refrigerator has a passage that connects the outlet to a defrosting pipe disposed in the evaporator, and defrosts by supplying high-temperature refrigerant discharged from the compressor to the defrosting pipe.

[0010] However, in the conventional refrigerator configuration disclosed in Patent Document 1, high-temperature refrigerant just discharged from the compressor is directly used for defrosting in order to utilize waste heat from the refrigerator, but since the refrigerant temperature depends on the compressor rotation speed and the outside air temperature, when the outside air temperature drops, the amount of heat is insufficient and it takes a long time to melt the frost on the evaporator and raise the temperature. During this time, the cooling operation to the inside of the refrigerator is stopped, so the temperature inside the refrigerator rises significantly.

[0011] The inventors have discovered the above-mentioned problems and have come up with the subject matter of the present disclosure in order to solve these problems.

[0012] Therefore, the present disclosure provides a refrigerator that uses waste heat for defrosting, compensates for changes in the heat quantity of the latent heat of condensation of the refrigerant, and can shorten the defrosting time and save energy regardless of changes in the outside air temperature or the state of frost on the evaporator, while also reducing the amount of re-cooling after defrosting.

[0013] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted.

[0014] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0015] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS.

[0016] [1-1.Configuration] 1 to 4, refrigerator 100 in this embodiment has a refrigerator compartment 101, a freezer compartment 102 separated from refrigerator compartment 101 by a partition 100a and located below refrigerator compartment 101, a first machine compartment 103 located on the upper back surface of refrigerator 100, and a second machine compartment 104 located on the lower back surface of refrigerator 100.

[0017] The first machine room 103 has, as components that constitute the refrigeration cycle 150, a compressor 105, a capacity adjustment condenser 133, a first machine room fan 116, and a suction pipe 126.

[0018] The second machine room 104 houses an evaporation tray 110 for receiving and evaporating defrost water generated when frost adhering to the evaporator 106 is melted, and a second machine room fan 109 for air cooling to promote evaporation is provided on the windward side. Also, a flow path switching valve 122 is provided in the second machine room 104.

[0019] A cooling chamber 117 is arranged at the back of the freezer chamber 102, and in the cooling chamber 117 there are provided an evaporator 106 that generates cold air, a cooling fan 111 that is located above the evaporator 106 and supplies the cold air generated by the evaporator 106 to the refrigerator chamber 101 and the freezer chamber 102, and a heating means 160 that melts and defrosts frost that has adhered to the evaporator 106.

[0020] The heating means 160 of the refrigerator 100 in this embodiment is a defrost heater 120 that is located below the evaporator 106 and heats the evaporator 106 by an indirect heating method using radiation, and an evaporator heating pipe 138 that is made up of a pipe that is in close contact with the portion between the divided fins 139 of the evaporator 106 and heats the evaporator 106 by a direct heating method using the latent heat of condensation of the refrigerant.

[0021] In this embodiment, the defrost heater 120 is a glass tube heater. The refrigerator 100 is equipped with a heating control means 153 that controls these heating means 160. The heating control means 153 is incorporated into a main body control board (not shown) of the refrigerator 100 and is composed of a defrost heater control means 153a that controls the amount of heating by the defrost heater 120 and a heating pipe control means 153b that controls the amount of heating by the evaporator heating pipe 138. Next, the evaporator 106 will be described with reference to FIG.

[0022] The evaporator 106 is of the fin-and-tube type, and a temperature sensor 115 for detecting the temperature of the evaporator 106 is installed in an inlet pipe portion (not shown) of the evaporator 106. The evaporator 106 is of a typical fin-and-tube type, and is formed by stacking evaporator cooling pipes 137, which are refrigerant pipes having fins 139, in the vertical direction, with the evaporator cooling pipes 137 arranged in roughly seven rows in the vertical direction and three rows in the front-to-back direction, and the rear side has the lowest row removed, leaving six rows, resulting in a piping pattern where the evaporator cooling inlet 143 and evaporator cooling outlet 144 of the evaporator 106 are at the same position on the upper right of the evaporator 106 when viewed from the front.

[0023] In this case, a recess (not shown) for fixing the evaporator heating pipe 138 is provided between the fins 139 of the end plate 140 located at one end of the evaporator 106, and the evaporator heating pipe 138 is fitted into this recess so that the fins 139 and the evaporator 106 are in close contact with each other.

[0024] Furthermore, by folding back the end of fin 139 that contacts evaporator heating pipe 138, evaporator heating pipe 138 and fin 139 contact each other as a surface rather than a point or line, thereby improving adhesion and increasing heat transfer efficiency. Evaporator heating pipe 138 has evaporator heating inlet 145 on the front side relative to the front of refrigerator 100 and evaporator heating outlet 146 on the back side.

[0025] The refrigerator compartment 101 also houses a refrigerator compartment duct 113 that supplies cold air to the refrigerator compartment 101, and a refrigerator compartment damper 114 that adjusts the amount of cold air supplied to the refrigerator compartment 101 by adjusting the angle or blocking the air. The opening and closing operation of the refrigerator compartment damper 114 is controlled by the temperature detected by a refrigerator compartment temperature sensor (not shown). A heating side evaporator 131 and a heating side evaporator fan 134 are disposed above the heating side evaporator 131 within the refrigerator compartment duct 113.

[0026] Next, the refrigeration cycle 150 of the refrigerator 100 will be explained using Figures 4, 5A, and 5B. Figures 5A and 5B are all Mollier diagrams with the vertical axis representing absolute pressure (kPa) and the horizontal axis representing specific enthalpy (kg / kg). Each diagram shows a schematic representation of the state at an arbitrary moment, and ignores details such as the influence of pressure loss in the piping.

[0027] The refrigerant discharged from compressor 105 exchanges heat with outside air in condenser 107, which is composed of capacity adjustment condenser 133 and a heat radiation pipe (not shown) arranged inside housing 100b, outer wall surface 100c, and top surface 100d, and condenses, leaving some gas behind. The refrigerant that has passed through condenser 107 has moisture removed by dryer 121 and flows into flow path switching valve 122.

[0028] The refrigerant flowing into the flow path switching valve 122 is in a two-phase state where liquid-phase refrigerant and gas-phase refrigerant are mixed. The flow path of the refrigerant is branched by the flow path switching valve 122 into a cooling path 151 and a defrosting path 152. The cooling path 151 is a path that supplies the refrigerant to the evaporator 106 to generate cold air. On the other hand, the defrosting path 152 is a path that heats the refrigerant and supplies the heated refrigerant to the evaporator 106 to perform defrosting.

[0029] First, the cooling path 151 will be described. The cooling path 151 is in cooling operation and is represented by the Mollier diagram of FIG. 5A. The cooling path 151 is connected to the compressor 105 at point a in FIG. 5A. This is the path through which the discharged refrigerant flows from the flow path switching valve 122 to the capillary tube which is the first throttle 124.

[0030] The refrigerant that has liquefied after passing through the condenser 107 at point b is decompressed by the first throttle 124 and evaporates in the evaporator 106 at point c. The refrigerant then evaporates in the evaporator 106 to generate cold air, which is used to cool the refrigerator compartment 101 and the freezer compartment 102. The refrigerant that has passed through the evaporator 106 returns to the compressor 105 at point d via a second heat exchange section (not shown), which is a heat exchange between the suction pipe 126 and the first throttle 124, as it passes through the suction pipe 126.

[0031] Next, the defrosting path 152 will be described.

[0032] Defrosting path 152 is shown during defrosting operation by the Mollier diagram in Fig. 5B. Defrosting path 152 is a path through which refrigerant discharged from compressor 105 at point e in Fig. 5B flows from flow path switching valve 122 to second throttle 127. At point f, the refrigerant is decompressed by second throttle 127, and at point g, the refrigerant that has passed through second throttle 127 is heated in first heat exchanger 128 by heat exchange with the path through which refrigerant is supplied from compressor 105 to condenser 107, and is vaporized (point h).

[0033] Thereafter, at point i, the vaporized refrigerant is sent to the evaporator heating inlet 145 of the evaporator 106. At point j, which is located from point i to the evaporator heating outlet 146, the vaporized refrigerant supplied to the evaporator 106 condenses and liquefies due to a phase change, generating latent heat of condensation, which heats the evaporator 106 and defrosts the evaporator 106. Thereafter, the refrigerant decompressed by the third throttle 129 located between point j and point k is returned to the compressor 105 at point L by evaporating the refrigerant condensed in the evaporator 106 from point k in the heating side evaporator 131 located in the refrigerator compartment 101, thereby changing the state of the refrigerant to a gas phase. As a result, the refrigerant flowing into the compressor 105 is in a gas phase, which prevents the refrigerant from flowing in as a dense liquid phase or a two-phase gas-liquid state, and therefore the parts inside the compressor 105 are not at risk of failure.

[0034] Furthermore, since the flow path switching valve 122 is positioned after the dryer 121, which has the slowest flow rate in the two-phase region of the refrigerant condensation process, the flow rate is about 1 / 40 of that of the gas phase discharged from the compressor 105, and flow noise generated from the flow path switching valve 122 and the evaporator 106 can be suppressed.

[0035] [1-2. Operation] The operation and function of the refrigerator 100 of the first embodiment configured as above will be described below.

[0036] The operation of the refrigerator 100 in the defrosting operation for defrosting the evaporator 106 will be described with reference to Fig. 6. Fig. 6 shows the passage of time from left to right.

[0037] "ON" of the compressor 105 indicates that the compressor 105 is operating. "OFF" of the compressor 105 indicates that the compressor 105 is stopped.

[0038] "ON" of the first machine room fan 116 indicates that the first machine room fan 116 is operating. Also, "OFF" of the first machine room fan 116 indicates that the first machine room fan 116 is stopped.

[0039] The "cooling" of the flow path switching valve 122 is performed by opening the flow path from the flow path switching valve 122 to the cooling path 151 and closing the flow path from the flow path switching valve 122 to the defrosting path 152. Furthermore, the "defrosting" state of the flow path switching valve 122 indicates that the flow path from the flow path switching valve 122 to the defrosting path 152 is open, and the flow path from the flow path switching valve 122 to the cooling path 151 is closed.

[0040] "ON" of the cooling fan 111 indicates that the cooling fan 111 is operating. "OFF" of the cooling fan 111 indicates that the cooling fan 111 is stopped.

[0041] The "open" state of the refrigerator damper 114 indicates that the refrigerator damper 114 is open. The "closed" state of the refrigerator damper 114 indicates that the refrigerator damper 114 is closed.

[0042] "ON" for the heating side evaporator fan 134 indicates that the heating side evaporator fan 134 is operating. "OFF" for the heating side evaporator fan 134 indicates that the heating side evaporator fan 134 is stopped.

[0043] The "ON" state of the defrost heater 120 indicates that the defrost heater 120 is energized and defrosting is being performed by the defrost heater 120. On the other hand, the "OFF" state of the defrost heater 120 indicates that the energization to the defrost heater 120 has stopped and defrosting is not being performed by the defrost heater 120.

[0044] Next, the operation at each timing will be described.

[0045] Timing T1 is the timing at which refrigerator 100 shifts from normal cooling operation to defrosting operation. The timing to shift to defrosting operation occurs, for example, when the cumulative operating time of compressor 105 since the previous defrosting time reaches a predetermined time, or when a certain time has passed. At timing T1, it is expected that the temperature of freezer compartment 102 will rise due to defrosting, so refrigerator 100 closes refrigerator compartment damper 114 to lower the temperature of freezer compartment 102 before starting defrosting.

[0046] Next, at timing T2, the state of the flow path switching valve 122 switches from "cooling" to "defrosting." At timing T2, the refrigerant flow path switches from the cooling path 151 to the defrosting path 152, and the refrigerant that has passed through the first heat exchanger 128 and evaporated beyond the saturated vapor line is supplied to the evaporator heating inlet 145 of the evaporator 106, where it is heated by the latent heat generated by condensation in the evaporator heating pipe 138, and defrosting begins.

[0047] At timing T2, the state of the refrigerator compartment damper 114 is switched from "closed" to "open." This is because the evaporator 106 is heated from the air side as well while circulating the air inside the refrigerator compartment 101, thereby evaporating the refrigerant remaining in the piping of the evaporator cooling pipe 137 of the evaporator 106 and returning it to the compressor 105.

[0048] Also, at timing T2, the state of heating-side evaporator fan 134 changes from "OFF" to "ON." This not only circulates the cold air generated by the evaporation of the refrigerant inside evaporator 106 into refrigerator compartment 101, but also increases the airflow rate compared to cooling fan 111 alone, allowing the refrigerant remaining in evaporator cooling pipe 137 of evaporator 106 to evaporate more quickly and return it to compressor 105. Furthermore, from timing T2, the refrigerant begins to evaporate in heating-side evaporator 131, generating cold air, and circulating this cold air inside refrigerator compartment 101 suppresses the temperature rise in refrigerator compartment 101 during defrosting.

[0049] Next, at timing T3, the state of the cooling fan 111 is switched from "ON" to "OFF", and the state of the refrigerator compartment damper 114 is switched from "open" to "closed". The reason why the refrigerator compartment damper 114 is closed and the cooling fan 111 is stopped is because the evaporator 106 is This is because the refrigerant remaining in the evaporator cooling pipe 137 evaporates, causing the temperature of the evaporator 106 to approach the air temperature in the refrigerator compartment 101, making heat exchange difficult.

[0050] Then, the state of the defrost heater 120 switches from "OFF" to "ON." When power is started to be supplied to the defrost heater 120, defrosting also starts from the lower side of the evaporator 106. At this time, the compressor 105 is "ON" and the defrost heater 120 is also "ON."

[0051] Due to the latent heat of condensation of the refrigerant flowing through the evaporator heating pipe 138, the capacity of the defrost heater 120 can be small, and in this embodiment, the applied voltage is reduced from 100V (180W) to 50V (45W).

[0052] In this embodiment, for example, when the outside air temperature is 32°C, the compressor 105 uses about 45 W of power to heat the refrigerant using the latent heat of condensation, and the capacity of the defrost heater 120 is about 45 W, so the total power used during defrosting is about 90 W. This is half the 180 W required when using only the defrost heater 120. This makes it possible to reduce the amount of power consumed during defrosting and to reduce power peaks.

[0053] At this time, as shown in Figure 7, the heating capacity using the latent heat of condensation of the refrigerant is affected by the outside air temperature. This is because the condensation temperature increases when the outside air temperature is high, such as in summer, and decreases when the outside air temperature is low, such as in winter. This is also related to the operating speed of the compressor 105.

[0054] For this reason, the capacity of the defrost heater 120 can be changed depending on the outside air temperature, the operating state, and the degree of frost buildup. In particular, as the outside air temperature drops, the refrigeration capacity of the compressor 105 becomes excessive, so the rotation speed of the compressor 105 is controlled by decreasing it, but this also reduces the amount of refrigerant circulating and the heating capacity. On the other hand, the minimum amount of heat required for defrosting to raise the temperature of the evaporator 106 to a threshold value or higher (10°C or higher in this embodiment) in order to refresh the evaporator 106 does not change. This is because the heat capacity of the evaporator 106 and surrounding components, and the ambient temperature inside the cooling chamber 117 remain the same even when the outside air temperature changes. The part that changes is the increase or decrease in the amount of latent heat of melting depending on the amount of frost that has built up.

[0055] Therefore, the lower the outside air temperature, the longer the defrosting time should be to ensure the required amount of heat, but the temperature in the freezer compartment 102 will rise. For this reason, in this embodiment, a second temperature sensor (not shown) is provided to detect the outside air temperature, and the defrost heater control means 153a changes the amount of heat (heating amount) of the defrost heater 120 according to the outside air temperature detected by the second temperature sensor, thereby suppressing power peaks and achieving energy savings without extending the defrosting time. Specifically, the applied voltage to the defrost heater 120 is increased by the amount of heat that is reduced as the outside air temperature drops. The voltage is set so as not to exceed 100V.

[0056] In addition, the defrost heater control means 153a, which controls the amount of heat generated by the defrost heater 120, changes the amount of heat generated, i.e., the applied voltage, depending on the duration and number of times the doors 101a and 102a are opened and closed, and the outside air humidity, thereby taking into consideration the increase in latent heat due to the amount of frost that has adhered.

[0057] Specifically, the amount of moisture that has entered refrigerator compartment 101 and freezer compartment 102 is estimated from the cumulative time that the door switches (not shown) installed in refrigerator compartment 101 and freezer compartment 102 have been open during the time that has elapsed since the end of the previous defrost, the internal volumes of refrigerator compartment 101 and freezer compartment 102, and the absolute humidity of the outside air, and a ratio is added to the applied voltage of defrost heater 120, which is calculated based on the outside air temperature, according to the estimated amount. This determination is made between timings T1 and T2 before defrosting begins.

[0058] As a result, when waste heat is utilized for defrosting as in this embodiment, the discharge temperature of the compressor 105 Since the temperature and condensation temperature are affected by the outside air temperature, the amount of heat added to the refrigerant changes. However, by controlling the amount of power supplied to the defrost heater 120 in accordance with the outside air temperature relative to the amount of heat required during defrosting, the change in the amount of heat of the condensation latent heat of the refrigerant can be compensated for, thereby shortening the defrosting time and saving energy regardless of changes in the outside air temperature or the state of frost on the evaporator 106.

[0059] In addition, the heating pipe control means 153b, which controls the amount of heating by the evaporator heating pipe 138, controls the rotation speed of the compressor 105 and the rotation speed of the first machine room fan 116 according to the outside air temperature, while also controlling the heating side evaporator fan 134.

[0060] Specifically, the temperature of the evaporator heating pipe 138 is controlled to be high while vaporizing at point h, and the temperature of the heating side evaporator 131 is controlled according to the temperature detected by a refrigerator compartment temperature sensor (not shown) so that the temperature of the intake pipe 126 of the compressor 105 and the refrigerator compartment 101 does not drop too much.

[0061] Timing T4 is the timing when the temperature detected by temperature sensor 115 reaches a predetermined temperature, and is the timing when refrigerator 100 determines that defrosting of evaporator 106 is completed. At timing T4, the state of compressor 105 switches from "ON" to "OFF", and the state of first machine room fan 116 also switches from "ON" to "OFF". In addition, the state of defrost heater 120 switches from "ON" to "OFF".

[0062] This stops the operation of the defrosting path 152, and maintains this state for a predetermined time from timing T4 to timing T6 until the pressure in the defrosting path 152 is approximately equalized. Meanwhile, the heating side evaporator fan 134 maintains the "ON" state for a predetermined time from timing T4 to timing T5.

[0063] At this time, refrigerator compartment 101 is in a cooling state, so by adjusting the time from timing T4 to timing T5, it is possible to prevent overcooling of refrigerator compartment 101. In this case, timing T5 occurs when the temperature detected by a refrigerator compartment temperature sensor arranged in refrigerator compartment 101 reaches a predetermined temperature. The refrigerator compartment temperature sensor is the same sensor as the one that controls the opening and closing of refrigerator compartment damper 114 during cooling operation.

[0064] Next, at timing T5, the state of the heating side evaporator fan 134 switches from "ON" to "OFF."

[0065] Next, at timing T6, the state of the flow path switching valve 122 switches from "defrost" to "cooling," and after maintaining this state for a predetermined time until the pressures in the defrosting path 152 and the cooling path 151 are substantially equalized, at timing T7 the state of the compressor 105 is switched from "OFF" to "ON" to start operation of the cooling path 151. The reason for maintaining this state for the predetermined time is to prevent unpleasant noise from being generated by a sudden flow of refrigerant when the flow path switching valve 122 is switched.

[0066] In addition, the heating side evaporator fan 134 is kept in the "ON" state from timing T4 to timing T5 and from timing T7 to timing T8 in order to quickly increase the temperature of the heating side evaporator 131, which is connected to the evaporator 106 via the suction pipe 126.

[0067] Compressor 105 starts operating cooling path 151 at timing T7, and waits a predetermined time until timing T8 when the temperature of evaporator 106 has dropped sufficiently, after which the state of heating side evaporator fan 134 changes from "ON" to "OFF" and the state of cooling fan 111 changes from "OFF" to "ON".

[0068] At timing T8, the refrigerator 100 shifts from the defrosting operation to the cooling operation.

[0069] [1-3. Effects, etc.] As described above, in this embodiment, refrigerator 100 utilizes waste heat from compressor 105 for defrosting, and includes evaporator 106, heating means 160, and heating control means 153. Heating means 160 heats evaporator 106 to perform defrosting. Heating control means 153 controls the amount of heating by heating means 160 depending on the outside air temperature.

[0070] For example, if the heating means 160 includes an evaporator heating pipe 138 that directly heats the evaporator 106 by utilizing the latent heat of condensation of the refrigerant, and a defrost heater 120 that indirectly heats the evaporator 106, the amount of heat generated by the evaporator heating pipe 138 decreases as the outside air temperature drops. However, by controlling the amount of power supplied to the defrost heater 120 with the heating control means 153, the change in the amount of heat generated by the latent heat of condensation of the refrigerant relative to the amount of heat required during defrosting can be compensated for, and efficient defrosting can be performed even if the outside air temperature drops. This allows energy savings to be achieved while suppressing power peaks without extending the defrosting time.

[0071] Furthermore, the heating control means 153 includes a defrost heater control means 153a and a heating pipe control means 153b. The defrost heater control means 153a may estimate the amount of moisture that has entered the refrigerator from the outside air humidity depending on not only the outside air temperature but also the number of times and duration of opening and closing of the doors 101a and 102a, and may control the applied voltage of the defrost heater 120 in accordance with the estimated amount in conjunction with the change in the outside air temperature.

[0072] As a result, the amount of heat required for the latent heat energy of water depending on the amount of frost on the evaporator 106 is taken into consideration. Normally, when frost forms, the defrosting time is extended, but with this embodiment, the defrosting time can be shortened and energy can be saved.

[0073] Furthermore, the heating pipe control means 153b controls the rotation speed of the compressor 105 and the rotation speed of the first machine room fan 116 in conjunction with the heating side evaporator fan 134 according to the outside air temperature. This allows for efficient defrosting while maintaining a high temperature of evaporator heating pipe 138 by utilizing the latent heat of condensation of the refrigerant even when the outside air temperature changes, and while the configuration of this embodiment has the advantage of being able to cool refrigerator compartment 101 even during defrosting, it also makes it possible to maintain the freshness of food stored in refrigerator compartment 101 while controlling the temperature of refrigerator compartment 101 so that it does not drop too much.

[0074] Furthermore, this embodiment is designed based on a high outdoor temperature, and the total heat amount from the defrost heater 120 and the evaporator heating pipe 138 does not exceed 100% even when the outdoor temperature is low. When the evaporator heating pipe 138 heats the evaporator 106, the refrigerant is first vaporized from a two-phase region close to the liquid phase, and then the condensation latent heat is used to heat the evaporator 106. Since not only the sensible heat of the refrigerant but also the latent heat of the two-phase region, which has a greater heat amount than the sensible heat, can be used, a larger amount of heat can be used for heating than when the latter half of the condensation process close to the liquid phase or the sensible heat after condensation is used for defrosting the evaporator 106. An efficiency approximately three times or more higher than the waste heat of the compressor 105 can be obtained. Furthermore, an efficiency three times or more higher than the efficiency of the defrost heater 120 can be obtained.

[0075] As a result, the amount of heat generated by the defrost heater 120 is small particularly when the outdoor air temperature is high, and the amount of heat generated by the defrost heater 120 is large when the outdoor air temperature is low because the amount of heat generated by the refrigerant decreases. However, the amount of power consumed can be reduced compared to when only the defrost heater 120 is used. Furthermore, the peak power consumption of the refrigerator 100 occurs during defrosting using the defrost heater 120 throughout the year, and this peak power consumption during defrosting can also be reduced by this embodiment. It is possible to suppress it.

[0076] (Embodiment 2) Hereinafter, the second embodiment will be described with reference to FIG.

[0077] [2-1.Configuration] Refrigerator 100 according to the present embodiment has the same configuration as refrigerator 100 according to the first embodiment, and a flow path of the refrigerant is branched into cooling path 151 and defrosting path 152 by flow path switching valve 122. During defrosting, the flow path becomes defrosting path 152, heats the refrigerant, and supplies the heated refrigerant to evaporator heating pipe 138 arranged around evaporator 106, thereby performing defrosting.

[0078] [2-2. Operation] The operation and function of the defrosting operation for defrosting the evaporator 106 of the refrigerator 100 in this embodiment configured as above will be described below with reference to FIG.

[0079] FIG. 8 shows the progression of time from left to right.

[0080] Timing T1 is the timing at which refrigerator 100 shifts from normal cooling operation to defrosting operation. The shift to defrosting operation occurs, for example, when the cumulative operating time of compressor 105 since the previous defrosting operation reaches a predetermined time, or when a certain amount of time has passed. At timing T1, it is expected that the temperature of freezer compartment 102 will rise due to defrosting, so refrigerator 100 closes refrigerator compartment damper 114 to lower the temperature of freezer compartment 102 before starting defrosting.

[0081] At timing T2, the state of flow path switching valve 122 switches from "cooling" to "defrosting." Also at timing T2, the state of refrigerator compartment damper 114 switches from "closed" to "open," and the state of heating-side evaporator fan 134 changes from "off" to "on." As a result, the refrigerant is heated by the latent heat generated by condensation in evaporator 106, and defrosting begins. At the same time, the refrigerant remaining in evaporator cooling pipe 137 of evaporator 106 is evaporated while cooling refrigerator compartment 101, thereby suppressing a temperature rise in refrigerator compartment 101 during defrosting and preventing liquid backflow into compressor 105.

[0082] Next, at timing T3, the state of cooling fan 111 switches from "ON" to "OFF," and the state of refrigerator compartment damper 114 switches from "open" to "closed." The reason for closing refrigerator compartment damper 114 and stopping cooling fan 111 is that the refrigerant remaining in evaporator cooling pipe 137 of evaporator 106 evaporates, causing the temperature of evaporator 106 to approach the air temperature of refrigerator compartment 101, making heat exchange difficult.

[0083] Next, at timing T4, the heating of the evaporator 106 through the defrosting path 152 ends, and this is determined when the temperature detected by the temperature sensor 115 reaches a predetermined temperature or when a predetermined time has passed. At timing T4, the state of the compressor 105 switches from "ON" to "OFF", and the state of the first machine room fan 116 also switches from "ON" to "OFF". Then, the state of the flow path switching valve 122 switches from "defrost" to "cooling", and the state of the defrost heater 120 switches from "OFF" to "ON".

[0084] As a result, the refrigerant moves from the defrosting path 152 to the cooling path 151, and the defrosting is efficiently performed by the thermosiphon effect during defrosting. The cooling path 151 and the defrosting path 152 join at the suction side of the compressor 105 and the heating side suction pipe 132, and the pressure inside the pipe becomes uniform. The temperature of the heating-side evaporator 131 also rises simultaneously with the rise in temperature of the evaporator 106 due to the thermosiphon effect while maintaining a balance so that the refrigerant in the heating-side evaporator 131 also rises due to the operation of the heating-side evaporator fan 134. Furthermore, the refrigerant in the heating-side evaporator 131 evaporates, and there is no shortage of refrigerant on the evaporator 106 side during cooling operation after defrosting.

[0085] Furthermore, by directly heating the evaporator 106 using the latent heat of condensation of the refrigerant via the evaporator heating pipe 138 and then energizing the defrost heater 120 to perform defrosting by indirect heating using radiant heat, the energization time of the defrost heater 120 can be shortened and the minimum amount of heat required to heat the evaporator 106 and surrounding components can be supplied regardless of the state of frost. As a result, energy savings can be achieved and the temperature rise in the refrigerator compartment 101 and the freezer compartment 102 can be suppressed.

[0086] At timing T5, the temperature detected by temperature sensor 115 reaches a predetermined temperature, and the refrigerator 100 determines that defrosting of the evaporator 106 is complete. At this timing, the state of the defrost heater 120 switches from "ON" to "OFF." This ends the defrosting.

[0087] Thereafter, at timing T6, the state of the heating side evaporator fan 134 switches from "ON" to "OFF", and at timing T7, the compressor 105 starts operating the cooling path 151. After waiting for a predetermined time until timing T8 when the temperature of the evaporator 106 has sufficiently dropped, the state of the heating side evaporator fan 134 switches from "ON" to "OFF" and the state of the cooling fan 111 switches from "OFF" to "ON".

[0088] At timing T8, the refrigerator 100 shifts from the defrosting operation to the cooling operation. The above is a series of operations during defrosting.

[0089] [2-3. Effects, etc.] As described above, in this embodiment, heating means 160 of refrigerator 100 comprises evaporator heating pipe 138 that directly heats evaporator 106 by utilizing the latent heat of condensation of the refrigerant, and defrost heater 120 that indirectly heats evaporator 106. During defrosting, evaporator 106 is heated by evaporator heating pipe 138 and then by defrost heater 120. As a result, the temperature of evaporator 106, to which evaporator heating pipe 138, which is heated by the latent heat of condensation of the refrigerant, is in close contact, rises uniformly and evenly. Therefore, with a low input, the temperature of evaporator 106 can be raised and frost can be melted while suppressing a temperature rise in refrigerator compartment 101 and freezer compartment 102.

[0090] Then, since heating is performed by the defrost heater 120 after a certain temperature rise has occurred, it is sufficient to ensure temperature rise not only for the evaporator 106 but also for melting frost adhering to the components around the evaporator 106 in the cooling chamber 117 and to prevent remaining ice, and the heating time can be significantly reduced.

[0091] The time and temperature gradient of the temperature rise inside refrigerator compartment 101 and freezer compartment 102 due to heating by defrost heater 120 is about three times the time and temperature gradient due to heat intrusion from the outside air, so shortening the heating time of defrost heater 120 not only saves energy during defrosting, but also saves energy by reducing the amount of heat supplied to the heater during defrosting and the input to compressor 105 required for re-cooling after defrosting.

[0092] Furthermore, this also suppresses the maximum temperature rise inside the refrigerator compartment 101 and the freezer compartment 102, thereby reducing temperature fluctuations in frozen foods and improving the freshness of the foods. Food and air that have risen in temperature during defrosting are rapidly cooled back to their original temperatures by recooling after defrosting, but during this recooling, the air, which has a lower specific heat, cools faster than the food, so the temperature difference between the food and the air becomes large, and the relationship of air temperature < food temperature continues.

[0093] During this period, moisture in the food evaporates, causing the quality of the stored food to deteriorate. Therefore, in this embodiment, the heating time for defrosting is shortened and the temperature rise in refrigerator compartment 101 and freezer compartment 102 is suppressed, so the time during which there is a temperature difference between the food and the air that occurs when re-cooling after defrosting is reduced, and deterioration of the freshness of the stored food can be suppressed, particularly for foods that may be stored for long periods, such as frozen foods. [Industrial Applicability]

[0094] When waste heat is used for defrosting, the present disclosure can compensate for the change in the heat quantity of the refrigerant, which is affected by the outside air temperature relative to the amount of heat required for defrosting, by controlling the amount of heating by the heating means.Therefore, regardless of annual temperature changes or the state of frost on the evaporator, it is possible to shorten the defrosting time and save energy, and the disclosure can be applied to domestic and commercial refrigerators. [Explanation of symbols]

[0095] 100 refrigerator 100a divider 100b housing 100c External wall surface 100d top 101 Refrigerator Doors 101a and 102a 102 Freezer 103 First Machine Room 104 Second Machine Room 105 Compressor 106 Evaporator 107 Condenser 109 Second machine room fan 110 Evaporating dish 111 Cooling fan 112 Freezer damper 113 Refrigerator duct 114 Refrigerator damper 115 Temperature Sensor 116 First machine room fan 117 Cooling room 120 Defrost heater 121 Dryer 122 Flow path switching valve 124 First Aperture 126 Suction pipe 127 Second Aperture 128 First heat exchange section 129 Third Aperture 131 Heating side evaporator 132 Heating side suction pipe 133 Capacity adjusting condenser 134 Heating side evaporator fan 137 Evaporator cooling pipe 138 Evaporator heating pipe 139 Finn 140 End Plate 143 Evaporator cooling inlet 144 Evaporator cooling outlet 145 Evaporator heating inlet 146 Evaporator heating outlet 150 Refrigeration Cycle 151 Cooling Path 152 Defrosting route 153 Heating control means 153a Defrost heater control means 153b Heating pipe control means 160 Heating means

Claims

1. A refrigerator having a cooling path in which a refrigerant is supplied from a compressor through a condenser to an evaporator, and having a refrigeration cycle in which a freezer compartment is cooled by the evaporator, The refrigeration cycle includes a flow path switching valve that can switch between the cooling path and a defrosting path, the defrosting path connects an evaporator heating pipe, which heats the refrigerant by heat exchange with the condenser and defrosts the evaporator with the heated refrigerant, to a heating-side evaporator; The refrigerating compartment is cooled by the heating side evaporator, When the flow path switching valve is switched to the cooling path side, the evaporator is not heated by the evaporator heating pipe, and the freezing compartment and the refrigerating compartment are cooled by the cold air generated by the evaporator, When the flow path switching valve is switched to the defrosting path side, the evaporator is defrosted by the evaporator heating pipe, and the refrigerating compartment is cooled by the cold air generated by the heating side evaporator.

2. A refrigerator as claimed in claim 1, characterized in that it is provided with a heating side evaporator fan near the heating side evaporator and a refrigerator compartment damper that adjusts the amount of cold air generated by the evaporator and supplied to the refrigerator compartment, and when the flow path switching valve is switched to the defrost path side, the heating side evaporator fan switches from OFF to ON and the refrigerator compartment damper switches from closed to open.

3. 2. The refrigerator according to claim 1, wherein the defrosting path includes a pressure reducing means between the evaporator heating pipe and the heating side evaporator.

4. A refrigerator as described in claim 1, wherein when the flow path switching valve is switched to the defrost path side, the evaporator is heated by the evaporator heating pipe and then heated by a defrost heater that indirectly heats the evaporator.

Images