CN116134276A - Refrigerator with a door - Google Patents

Abstract

The refrigeration cycle of the refrigerator of the present invention branches into the following two paths on the downstream side of the 1 st condenser: a cooling passage for supplying a refrigerant to the evaporator to generate cool air; and a defrosting path for defrosting by heating the refrigerant and supplying the heated refrigerant to the evaporator, wherein the refrigerant flowing through the cooling path is supplied to the evaporator after passing through the 2 nd condenser, the refrigerant flowing through the defrosting path is heated by heat exchange with a path for supplying the refrigerant from the compressor to the 1 st condenser, the evaporator thermally coupled to the defrosting path is heated, and the refrigerant having dissipated heat in the defrosting path is evaporated in a heating side evaporator provided on a downstream side of the evaporator and returned to the compressor.

Description

Refrigerator with a door

Technical Field

The present invention relates to a refrigerator.

Background

Patent document 1 discloses a refrigerator that performs defrosting. The refrigerator is provided with a passage connecting an outlet of the compressor and a defrosting pipe disposed in the evaporator, and the refrigerator is defrosted by supplying a high-temperature refrigerant discharged from the compressor to the defrosting pipe.

Patent document 2 similarly discloses a refrigerator that performs defrosting. The refrigerator uses a four-way valve to replace the path between the evaporator and the external condenser, supplies high-temperature refrigerant discharged from the compressor to the evaporator to defrost the refrigerator, and evaporates the refrigerant in the external condenser and returns the refrigerant to the compressor.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 58-024774

Patent document 2: japanese patent laid-open publication No. 2018-004170

Disclosure of Invention

The invention provides a refrigerator, which can inhibit the generation of unpleasant sound for users and inhibit the temperature rise in the refrigerator during defrosting, thereby reducing the recooling amount after defrosting.

The refrigerator of the present invention has a refrigeration cycle including at least a compressor, a 1 st condenser, a 2 nd condenser, and an evaporator, and the refrigeration cycle is branched into two paths on the downstream side of the 1 st condenser: a cooling passage for supplying a refrigerant to the evaporator to generate cool air; and a defrosting path for defrosting by heating the refrigerant and supplying the heated refrigerant to the evaporator, wherein the refrigerant flowing through the cooling path is supplied to the evaporator after passing through the 2 nd condenser, the refrigerant flowing through the defrosting path is heated by heat exchange with a path for supplying the refrigerant from the compressor to the 1 st condenser, the evaporator thermally coupled to the defrosting path is heated, and the refrigerant having dissipated heat in the defrosting path is evaporated in a heating side evaporator provided on a downstream side of the evaporator and returned to the compressor.

The refrigerator of the present invention can use the condensation heat of the refrigerant for defrosting, and can reduce the sub-cooling amount after defrosting by suppressing the generation of unpleasant sound for the user and suppressing the temperature rise in the refrigerator during defrosting.

Drawings

Fig. 1 is a longitudinal sectional view of a refrigerator according to embodiment 1.

Fig. 2 is a diagram showing the structure of the 1 st and 2 nd machine rooms of the refrigerator according to embodiment 1.

Fig. 3 is a construction diagram of a refrigeration cycle of the refrigerator according to embodiment 1.

Fig. 4A is a Mollier chart (Mollier chart) of the refrigerator according to embodiment 1 during a cooling operation.

Fig. 4B is a mollier diagram of the refrigerator according to embodiment 1 in the defrosting operation.

Fig. 5 is a diagram of a structure in a cooling chamber of a refrigerator according to embodiment 1.

Fig. 6 is a perspective view of an evaporator of the refrigerator according to embodiment 1.

Fig. 7 is a diagram showing control during defrosting of the refrigerator according to embodiment 1.

Fig. 8 is a flowchart of defrosting of the refrigerator according to embodiment 1.

Fig. 9 is a construction diagram of a refrigeration cycle of a refrigerator according to embodiment 2.

Fig. 10 is a diagram showing control during defrosting of the refrigerator according to embodiment 2.

Detailed Description

(knowledge based on the present invention, etc.)

A refrigerator having a defrosting function of melting frost adhering to an evaporator is known. The defrosting function is generally to provide a defrosting heater below the evaporator, and to melt frost by energizing the defrosting heater to defrost the frost. On the other hand, patent document 1 discloses a refrigerator provided with a passage connecting an outlet of a compressor and a defrosting pipe provided in an evaporator, and configured to defrost by supplying a high-temperature refrigerant (cooling medium) discharged from the compressor to the defrosting pipe. The refrigerator of patent document 1 can use heat of a compressor for defrosting.

Patent document 2 discloses a refrigerator in which a path between an evaporator and an external condenser is replaced with a four-way valve, a high-temperature refrigerant discharged from a compressor is supplied to the evaporator to defrost the refrigerator, and the refrigerant is evaporated in the external condenser and then returned to the compressor. As with the refrigerator of patent document 1, the refrigerator of patent document 2 can use heat of the compressor for defrosting.

The conventional refrigerator disclosed in patent document 1 uses a three-way valve to switch the flow path of the refrigerant to a defrosting pipe during defrosting. Since the flow rate of the refrigerant flowing through the three-way valve is high, sound is generated in the three-way valve or the evaporator. The sound is unpleasant for a user in the vicinity of the refrigerator.

In the conventional refrigerator disclosed in patent document 2, condensation may occur around the refrigerator due to cool air generated in the external condenser during defrosting. In addition, since the refrigerator releases the condensation heat of the refrigerant recovered in the refrigerator as evaporation heat to the outside, the refrigerator does not operate as a refrigerator during defrosting.

In addition, in low outside air at 16 ℃ or lower, the fan of the machine room is not normally operated. This is to suppress a decrease in the efficiency of the cooling system due to supercooling of the refrigerant or an increase in the viscosity of the compressor oil. In the structure of the refrigerator disclosed in patent document 2, the temperature in the machine room is lowered due to cool air generated in the external condenser at the time of defrosting, and the cooling efficiency is lowered, resulting in an increase in the amount of electricity.

In general, the operation of the compressor is stopped during defrosting, and a defrosting heater provided below the evaporator is energized to defrost the evaporator. Since the cooling operation is stopped during defrosting, the temperature in the refrigerator increases due to the outside air temperature, and the temperature of the food stored in the refrigerator also increases. After defrosting is completed, the cooling operation is required, including a temperature rise portion that increases the temperature during defrosting.

The inventors found that the above problems exist, and have arrived at the subject of the present invention in order to solve the problems.

Accordingly, the present invention provides a refrigerator capable of suppressing the generation of unpleasant sounds for the user, suppressing the increase in the temperature in the refrigerator during defrosting, and reducing the amount of sub-cooling after defrosting.

The embodiments are described in detail below with reference to the drawings. However, unnecessary detailed description may be omitted. For example, a detailed description of known matters or a repeated description of practically the same structure may be omitted.

In addition, the drawings and the following description are provided to facilitate a full understanding of the invention by those skilled in the art, and are not intended to limit the scope of the invention.

(embodiment 1)

Next, embodiment 1 will be described with reference to fig. 1 to 8.

(1-1. Structure)

In fig. 1 and 2, a refrigerator 100 according to the present embodiment includes: a refrigerating chamber 101; a freezing chamber 102 separated from the refrigerating chamber 101 by a partition plate 100a and provided at a lower portion of the refrigerating chamber 101; a 1 st machine room 103 provided on the upper back surface of the refrigerator 100; and a 2 nd machine room 104 provided in a lower portion of the back surface of the refrigerator 100.

The 1 st machine room 103 houses a compressor 105, a capacity adjustment condenser 133, a 1 st machine room fan 116, and a suction pipe 126, which are components constituting a refrigeration cycle 150.

The 2 nd machine room 104 is divided into two areas by a partition wall 108. A 2 nd mechanical room fan 109 for cooling the 1 st condenser 107 by air is provided in the partition wall 108. The 2 nd machine room 104 houses the 1 st condenser 107 on the upstream side of the 2 nd machine room fan 109, and houses the evaporation pan 110 on the downstream side of the 2 nd machine room fan 109. The 2 nd machine chamber 104 also houses a flow path switching valve 122.

A cooling chamber 117 is disposed on the back surface of the freezing chamber 102. The cooling chamber 117 houses the evaporator 106, the cooling fan 111 located above the evaporator 106, and the defrost heater 120 located below the evaporator 106. The evaporator 106 generates cool air. The cooling fan 111 supplies cool air generated in the evaporator 106 to the refrigerating compartment 101 and the freezing compartment 102. The defrosting heater 120 is a defrosting device for defrosting by melting frost attached to the evaporator 106.

In the present embodiment, the defrosting heater 120 is a glass tube heater. Various defrosting apparatuses are used, and for example, a tube heater, a surface heater, and the like are also generally used. The cooling chamber 117 accommodates a freezing chamber damper 112 for blocking cool air supplied to the freezing chamber 102 and adjusting the air volume.

The evaporator 106 is a fin-tube evaporator. The evaporator 106 is provided with a temperature sensor 115 for detecting the temperature of the evaporator 106 at an inlet pipe portion (not shown) of the evaporator 106. In the present embodiment, the temperature sensor 115 is provided at the inlet pipe portion, but is not limited thereto. The temperature sensor 115 may be provided at a portion where the temperature increases most slowly during defrosting, so that frost remaining during defrosting can be prevented.

The refrigerating room 101 accommodates a refrigerating room duct 113 for supplying cool air to the refrigerating room 101, and a refrigerating room damper 114 for adjusting the amount of cool air supplied to the refrigerating room 101 by angle adjustment, partition, or the like. The opening and closing operation of the refrigerating compartment damper 114 is controlled based on the detected temperature of a refrigerating compartment temperature sensor (not shown) that detects the temperature in the refrigerating compartment 101. The refrigerating compartment duct 113 accommodates the heating side evaporator 131 and a heating side evaporator fan 134 above the heating side evaporator 131.

Next, a refrigeration cycle 150 of the refrigerator 100 will be described with reference to fig. 3, 4A, and 4B. Fig. 4A, 4B are mollier diagrams with the vertical axis represented by absolute pressure (kPa) and the horizontal axis represented by enthalpy (kJ/kg). The state at any moment is schematically shown, and minute parts such as the influence of pressure loss in the piping are ignored.

The refrigerant discharged from the compressor 105 is subjected to heat exchange with the outside air through the capacity-adjusting condenser 133 and the 1 st condenser 107, and is condensed while leaving a part of the gas. The refrigerant having passed through the 1 st condenser 107 is dehumidified by the dryer 121 and flows into the flow path switching valve 122.

The refrigerant flowing into the flow path switching valve 122 is in a two-phase state in which the liquid-phase refrigerant and the gas-phase refrigerant are mixed. The flow path of the refrigerant is branched into a cooling passage 151 and a defrost passage 152 by a flow path switching valve 122. The cooling passage 151 is a path for supplying the refrigerant to the evaporator 106 to generate cool air. On the other hand, the defrost path 152 is a path for defrosting by heating the refrigerant and supplying the heated refrigerant to the evaporator 106.

First, the cooling passage 151 will be described. The refrigerant in the cooling passage 151 exhibits the condition shown in the mollier diagram of fig. 4A at the time of the cooling operation. The cooling passage 151 is a path for the refrigerant discharged from the compressor 105 at the point a in fig. 4A to flow from the flow path switching valve 122 to the 2 nd condenser 123. The 2 nd condenser 123 climbs inside the main body side of the portion of the door of the refrigerator 100 (either one or both of the door 101a of the refrigerator compartment 101 and the door 102a of the freezer compartment 102) that is in contact with the refrigerator main body.

The refrigerant passing through the 2 nd condenser 123 radiates heat to the outside, thereby heating the doors 101a and 102a of the refrigerator 100 and the partition plate 100a in the refrigerator, and preventing dew condensation from occurring in the doors 101a and 102a of the refrigerator 100 or gaskets (not shown) attached to these doors.

The refrigerant liquefied by passing through the 2 nd condenser 123 at the point b is decompressed by the 1 st throttle part 124, and evaporated from the evaporator 106 at the point c. Then, the refrigerant evaporates in the evaporator 106 to generate cool air. The cold air is used for cooling the refrigerating compartment 101 and the freezing compartment 102. The refrigerant passing through the evaporator 106 returns to the compressor 105 at point d via the suction pipe 126.

Next, the defrosting passage 152 will be described.

The refrigerant in the defrost path 152 exhibits a condition shown in the mollier chart (mollier chart) of fig. 4B during the defrosting operation. The defrost path 152 is a path for causing the refrigerant discharged from the compressor 105 at the point e in fig. 4B to flow from the flow path switching valve 122 to the 2 nd throttle portion 127. At point f, the refrigerant is depressurized by the 2 nd throttle portion 127. At point g, the refrigerant having passed through the 2 nd expansion portion 127 is heated and gasified by heat exchange with the refrigerant supplied from the compressor 105 to the 1 st condenser 107 in the 1 st heat exchange portion 128 (point h).

The vaporized refrigerant is then supplied to the evaporator 106. The vaporized refrigerant condenses and liquefies between the point i and the point j due to the phase change, thereby generating latent heat of condensation, and the evaporator 106 is heated by the latent heat of condensation. Defrosting of the evaporator 106 is achieved by this heating. Thereafter, the refrigerant condensed in the evaporator 106 evaporates in the heating-side evaporator 131 disposed in the refrigerating chamber 101 from the point k to the point l, and turns into a gas phase state. The refrigerant returns to the compressor 105 at point l. Accordingly, the refrigerant flowing into the compressor 105 is in a gas phase, and thus can be prevented from flowing in a high-density liquid phase or a gas-liquid two-phase state, and therefore components in the compressor 105 are not put at risk of failure.

Next, the 1 st heat exchanging portion 128 will be described.

The 1 st heat exchange portion 128 gasifies the refrigerant condensed in the capacity-adjusting condenser 133 and the 1 st condenser 107 from point g to point h in fig. 4B.

In the present embodiment, the 1 st heat exchange portion 128 is formed by partially welding, for example, about 1m to 2m, a pipe through which the refrigerant discharged from the 2 nd throttle portion 127 flows and a pipe through which the refrigerant is supplied from the compressor 105 to the 1 st condenser 107.

Further, the 1 st heat exchanging portion 128 is formed on the outer wall surface 100c of the casing 100b of the refrigerator 100, so that sensible heat of the casing 100b made of an iron plate can be used for heating the refrigerant in the defrost path 152. In the present embodiment, the 1 st heat exchanging portion 128 is adhered to the outer wall surface 100c with an aluminum tape (not shown).

Specifically, in the present embodiment, in the 1 st heat exchange portion 128, the pipe for supplying the refrigerant from the compressor 105 to the 1 st condenser 107 has a diameter Φ3.6mm. The pipe through which the refrigerant discharged from the 2 nd throttle portion 127 flows has a diameter Φ3.2mm. The length of the weld for heat exchange was 1.2m.

Here, the flow rate is also slower as the diameter of the pipe through which the refrigerant discharged from the 2 nd expansion portion 127 flows is larger, and the heat exchange amount is increased. The diameter of the pipe through which the refrigerant discharged from the 2 nd throttle portion 127 flows is the same as or smaller than the diameter of the pipe through which the refrigerant is supplied to the 1 st condenser 107. Thus, the refrigerant circulation amount is adjusted according to the resistance of the 2 nd throttle portion 127, so that the temperature difference between the inlet portion 128a and the outlet portion 128b of the 1 st heat exchange portion 128 in the defrost path 152 becomes about 7K or more. Thus, at the outlet of the 1 st heat exchange portion 128, the refrigerant can be brought into a gas phase state beyond the saturated vapor line.

Further, since the refrigerant passes through the capacity-adjusting condenser 133 and the 1 st condenser 107, a part of the refrigerant is liquefied, the volume of the refrigerant is reduced, and the flow rate of the refrigerant flowing through the flow path switching valve 122 is reduced. In the condensation piping in the refrigeration cycle 150, the state of the refrigerant near the outlet of the 1 st condenser 107 is a state that is also close to the liquid phase in the two-phase region.

For example, at condensing pressure: 464kPa (35 ℃), evaporation pressure: in the case of 72kPa (-20 ℃ C.), if the cylinder volume of the compressor 105 is 9.1cc and the rotation speed is 25rps, the refrigerant circulation amount is approximately 0.32g/s. The flow rate of the refrigerant passing through the condenser was 4.29m/s on the gas phase side and 0.10m/s on the liquid phase side in the two-phase region. The larger the flow rate, the larger the sound generated from the flow path switching valve 122 and the evaporator 106, and thus the user is made uncomfortable.

In the present embodiment, the gas-phase refrigerant having a high flow rate discharged from the compressor 105 does not directly flow through the flow path switching valve 122. Therefore, the flow path switching valve 122 can suppress the generation of a sound unpleasant to the user. In addition, the high flow rate vapor phase refrigerant does not also enter the evaporator 106. Therefore, noise generated when the refrigerant having a high flow rate enters the evaporator 106 and is rapidly condensed can be suppressed.

Next, the defroster passage 152 will be described with reference to fig. 5 and 6.

Fig. 5 is a diagram showing a structure of the cooling chamber 117 of the refrigerator 100. Fig. 6 is a diagram of the evaporator 106. In the cooling chamber 117, there is a refrigerating chamber return duct 119 to the right of the evaporator 106, through which cold air circulated in the refrigerating chamber 101 flows into the evaporator 106. The cool air flows into the lower portion of the evaporator 106 from the right lower portion of the evaporator 106. The cold air heat-exchanged with the evaporator 106 is circulated again to the refrigerating compartment 101 and the freezing compartment 102. A cooling fan 111 for supplying cool air to the refrigerating compartment 101 and the freezing compartment 102 is disposed above the evaporator 106, and a defrosting heater 120 is disposed below the evaporator.

The evaporator 106 is a representative fin-tube evaporator. The evaporator 106 is formed by stacking an evaporator cooling tube 137 in the up-down direction, and the evaporator cooling tube 137 is a refrigerant tube having fins 139.

The evaporator 106 includes the evaporator cooling pipes 137 arranged in 7 layers substantially in the up-down direction and in 3 rows in the front-rear direction. By employing 6 layers with the lowest layer removed on the back side, the evaporator cooling inlet 143 and the evaporator cooling outlet 144 of the evaporator 106 are formed in a piping pattern at the same position on the upper right of the evaporator 106 when viewed from the front.

In this way, the welding position is made closer at the time of mounting the evaporator 106 in the manufacturing process, the work is easier, the number of man-hours can be reduced, and the frost resistance is expected to be improved by eliminating the evaporator cooling tube 137 at the lowest layer.

In general, frost adhering to the evaporator 106 adheres to a large amount of inflow ports for return cool air from inside the bank flowing into the evaporator 106. In particular, frost tends to adhere to an inflow portion of the refrigerator return cool air, which flows in from the refrigerator 101 having high humidity through the refrigerator return duct 119.

In the present embodiment, the evaporator cooling tube 137 is pulled out by 1 layer and shortened, whereby the adhesion of frost and the obstruction of the air passage due to growth can be suppressed. In this way, even under overload conditions due to moisture entering the warehouse by opening and closing the doors 101a and 102a under high temperature and humidity conditions such as summer, deterioration of cooling due to obstruction of the air passage by frost growth is less likely to occur, and the effect of improving product quality is obtained. Further, in the fins 139, too, the space between the fins is increased in the lower portion into which a large amount of water flows from the upper portion of the evaporator 106, and thus, the frost is less likely to be connected and blocked.

The fins 139 of the evaporator 106 in the present embodiment are divided into fins 139 with respect to the evaporator cooling tubes 137 stacked in the vertical direction. An evaporator heating pipe 138 is mounted between the stacked evaporator cooling pipe 137 and the fins 139 so as to cover the outer periphery of the evaporator 106. The evaporator heating pipes 138 are attached to end plates 140 disposed at both ends of the evaporator 106. The end plates 140 are usually fixed from both sides of the evaporator 106 with a plate thickness thicker than the fins 139 so as to keep the tubes of the evaporator 106 in order.

In this case, as shown in fig. 6, a fixing recess (not shown) for the evaporator heating pipe 138 is provided in a portion between the fins 139 of the end plate 140, and the evaporator heating pipe 138 is fitted into the portion so as to be in close contact with the fins 139 and the evaporator 106. Further, since the end portions of the fins 139 that contact the evaporator heating pipes 138 are folded back, the evaporator heating pipes 138 are in surface contact with the fins 139, not in point or line contact, and therefore, the adhesion can be improved and the heat transfer efficiency can be improved.

The evaporator heating pipe 138 of the refrigerator 100 according to the present embodiment is formed to be attached from the upper portion to the lower portion of the evaporator 106 centering on the upper portion where the heat of the defrosting heater 120 is hard to reach, and a Φ6.35mm pipe is used. The total number of the evaporator heating pipes 138 is 12 in the front-rear direction of the evaporator 106, and the evaporator heating pipes 138 are closely attached to each other as a pipe heater so as to be sandwiched from the outside of the evaporator 106, but may be integrally formed with the evaporator cooling pipe 137 of the evaporator 106. In this case, the evaporator heating pipe 138 is passed between the pipes of the evaporator cooling pipe 137, so that the evaporator 106 can be heated from the vicinity of the evaporator cooling pipe 137 having the lowest temperature, and therefore, the defrosting effect is expected to be improved.

This time, the temperature is increased from the outer periphery to the inner side of the evaporator 106, and thus the temperature of the entire evaporator 106 can be equalized. Further, since the evaporator heating inlet 145 of the evaporator heating pipe 138 is set as the upper portion of the evaporator 106, and heating is started from a portion near the evaporator accumulator 141 where the refrigerant stays and the temperature rises slowly, the temperature rise can be promoted.

Here, as the refrigerant of the refrigeration cycle 150 in recent years, isobutane, which is a flammable refrigerant having a small global warming potential, is used from the viewpoint of protecting the global environment. The specific gravity of the hydrocarbon, i.e., isobutane, was about 2 times (at 2.04 and 300K) that of air at normal temperature and atmospheric pressure. This reduces the refrigerant charge amount, reduces the cost, and reduces the leakage amount of the flammable refrigerant in the event of leakage, thereby further improving the safety.

In the present embodiment, isobutane is used as the refrigerant, and as a countermeasure against explosion, the maximum temperature of the outer contour of the defrosting heater 120, that is, the glass tube surface, formed by the glass tube heater at the time of defrosting is restricted. Therefore, in order to reduce the temperature of the surface of the glass tube, a double glass tube heater is used in which the glass tube is formed into a double layer. In addition, as a method for reducing the temperature of the surface of the glass tube, a member (for example, an aluminum fin) having high heat radiation property may be wound around the surface of the glass tube. In this case, the glass tube is formed of a single layer, and the external dimension of the defrosting heater 120 can be reduced.

The refrigerant passes through the 1 st heat exchange portion 128, is vaporized beyond the saturated vapor line, flows into the evaporator heating inlet 145, and passes through the evaporator heating outlet 146. In this portion, since the refrigerant vaporized at the point h is condensed again from the point i to the point j in fig. 4B to heat the evaporator heating pipe 138 by the latent heat of condensation of the refrigerant, the temperature of the evaporator 106 increases, and the frost adhering to the evaporator 106 melts.

The reason why the evaporator 106 is heated by the latent heat of condensation after vaporizing the refrigerant from the two-phase region near the liquid phase such as the g point is that a larger amount of heat can be obtained than when the refrigerant flows into the evaporator 106 from the state of the refrigerant at the f point and is heated.

For example, the case where the refrigerant temperature is 32 ℃ will be described as an example. The liquid refrigerant is on the left side of the saturated liquid line in fig. 4A, and changes sensible heat. The sensible heat amount at this time was 2.48kJ/kg. Even at the same refrigerant temperature of 32 ℃, the change in latent heat becomes in the two-phase region between the saturated liquid line and the saturated vapor line, and the heat amount thereof is 321kJ/kg, so that the difference thereof is very large, about 130 times.

The value obtained by multiplying the difference by the refrigerant circulation amount is the amount of heat heated by the evaporator 106. As described in this embodiment, when the heat of the primary vaporization of the sensible heat is used, particularly large heat can be obtained, compared to the case where the sensible heat amount near the second half of the liquid phase in the condensation process or after condensation is used for defrosting the evaporator.

Thus, the temperature of the evaporator 106 can be raised at the time of defrosting and the temperature detected by the temperature sensor 115 can be guided to a predetermined temperature by heating using the latent heat of condensation, depending on conditions such as the case where the adhered frost is small. Therefore, the power consumption and the peak power can be reduced during defrosting without using a heater.

Then, the refrigerant condensed while heating the evaporator 106 flows out from the evaporator heating outlet 146, is depressurized again by the 3 rd throttle part 129, and is supplied to the heating-side evaporator 131 at the point k via the multistage expansion circuit 130.

The evaporation temperature of the refrigerant in the heating-side evaporator 131 is adjusted according to the amount of decompression of the 3 rd throttle part 129 and the rotation speed of the compressor 105, and is usually maintained at-25 to-10 ℃. A heating side evaporator fan 134 is disposed above the heating side evaporator 131, and is housed in the refrigerating compartment duct 113.

In general, when the evaporator 106 is heated by using the defrosting passage 152, it is necessary to extract cooling heat corresponding to the heating amount of the evaporator 106 from the heating side evaporator 131. On the other hand, the heating amount of the evaporator 106 is 2 to 3 times that of the waste heat of the compressor 105 and the like, and therefore, defrosting of the evaporator 106 can be performed efficiently.

In this case, the heating side evaporator 131 can extract heat from the inside of the refrigerating chamber 101, and the refrigerating chamber 101 can be cooled by the heating side evaporator fan 134 using the refrigerating chamber duct 113 at the time of cooling. Normally, the compressor 105 is stopped and defrosting is performed by the defrosting heater 120. However, in the present embodiment, defrosting can be performed without stopping the cooling when the operation of the compressor 105 is stopped.

The refrigerant having passed through the heating side evaporator 131 returns to the compressor 105 at point l via the heating side suction pipe 132 and the suction pipe 126.

The 3 rd throttle portion 129 is formed of a capillary tube having an inner diameter Φ0.5 to 1 mm. The multistage expansion circuit 130 as a secondary capillary is constituted by a small diameter tube having a diameter of 1.5 to 3 mm. The capillary tube and the small-diameter tube gradually become thicker toward the refrigerant pipe (not shown) having an inner diameter of Φ6 to 9mm of the heating-side evaporator 131. Accordingly, problems such as dew condensation water outflow are reduced by suppressing the occurrence of abnormal noise due to severe expansion of the refrigerant or a change in speed, and reducing the amount of frost formed on the tube surface by suppressing the outer surface area of the tube.

Therefore, it is preferable that most of the 3 rd throttle portion 129 is embedded in a heat insulating material (not shown) constituting the casing 100b of the refrigerator 100, and only a portion of the multistage expansion circuit 130 and a connection portion between the heating side evaporator 131 are exposed from the periphery of the refrigerating chamber duct in the refrigerating chamber 101.

(1-2. Operation)

Next, the operation and operation of the refrigerator 100 according to embodiment 1 configured as described above will be described.

The operation of the refrigerator 100 in the defrosting operation for defrosting the evaporator 106 will be described with reference to fig. 7. Fig. 7 shows the passage of time from left to right.

The "ON" of the compressor 105 indicates that the compressor 105 is operating. In addition, "OFF" of the compressor 105 indicates that the compressor 105 is stopped.

The "ON" of the 1 st mechanical room fan 116 indicates that the 1 st mechanical room fan 116 is operating. The "OFF (OFF)" of the 1 st mechanical room fan 116 indicates that the 1 st mechanical room fan 116 is stopped.

The "cooling" of the flow path switching valve 122 indicates that the flow path from the flow path switching valve 122 to the cooling passage 151 is open, and the flow path from the flow path switching valve 122 to the defrost passage 152 is closed. The "defrost" of the flow path switching valve 122 indicates that the flow path from the flow path switching valve 122 to the defrost path 152 is open, and that the flow path from the flow path switching valve 122 to the cooling path 151 is closed. The "full-closed" of the flow path switching valve 122 indicates that both the flow path from the flow path switching valve 122 to the cooling passage 151 and the flow path from the flow path switching valve 122 to the defrost passage 152 are closed.

The "ON" of the cooling fan 111 indicates that the cooling fan 111 is operating. The "OFF (OFF)" of the cooling fan 111 indicates that the cooling fan 111 is stopped.

The "open" of the freezing compartment damper 112 means that the freezing compartment damper 112 is open. In addition, "closing" of the freezing compartment damper 112 means that the freezing compartment damper 112 is closed.

The "open" of the refrigerating compartment damper 114 means that the refrigerating compartment damper 114 is open. In addition, "closing" of the refrigerating compartment damper 114 means that the refrigerating compartment damper 114 is closed.

The "ON" of the heating side evaporator fan 134 indicates that the heating side evaporator fan 134 is operating. In addition, "OFF" of the heating-side evaporator fan 134 indicates that the heating-side evaporator fan 134 is stopped.

The "ON" of the defrost heater 120 indicates that the defrost heater 120 is energized and the defrost heater 120 is defrosting. On the other hand, "OFF" of the defrosting heater 120 indicates that energization of the defrosting heater 120 is stopped, and the defrosting heater 120 does not defrost.

The time T1 is a time when the refrigerator 100 shifts from the normal cooling operation to the defrosting operation. The timing of transition to the defrosting operation is, for example, a timing when the running time of the compressor 105 has reached a predetermined time since the last defrosting time, a timing when a predetermined time has elapsed, or the like. At time T1, since it is assumed that the temperature of the freezing compartment 102 increases due to defrosting, the refrigerator 100 temporarily opens the freezing compartment damper 112, and reduces the temperature of the freezing compartment 102 before defrosting starts.

Next, at time T2, the state of the flow path switching valve 122 is switched from "cooling" to "defrosting". At time T2, the flow path of the refrigerant is switched from the cooling passage 151 to the defrosting passage 152, whereby the refrigerant vaporized by passing through the 1 st heat exchange portion 128 beyond the saturated vapor line is supplied to the evaporator 106, and the evaporator 106 is heated by latent heat generated by condensation in the evaporator 106, and defrosting is started.

At time T2, the state of the freezing compartment damper 112 is switched from "open" to "closed", and the state of the refrigerating compartment damper 114 is switched from "closed" to "open". This is to circulate air in the refrigerating chamber 101 and to heat the evaporator 106 from the air side, so that the refrigerant remaining in the piping of the evaporator 106 is evaporated and returned to the compressor 105.

In addition, at time T2, the state of the heating-side evaporator fan 134 changes from "OFF" to "ON". This not only circulates cool air generated by evaporation of the internal refrigerant in the evaporator 106 in the refrigerating compartment 101, but also increases the air volume of the cooling fan 111 alone, so that the refrigerant remaining in the evaporator cooling pipe 137 of the evaporator 106 can be evaporated and returned to the compressor 105 more quickly. Then, since the start of the evaporation of the refrigerant in the heating side evaporator 131 at time T2, cool air is generated from the refrigerant. By circulating the cool air in the refrigerator compartment 101, the temperature of the refrigerator compartment 101 is suppressed from rising during defrosting.

Next, at time T3, the state of the cooling fan 111 is switched from "ON (ON)" to "OFF (OFF)", and the state of the refrigerating compartment damper 114 is switched from "open" to "closed". The refrigerating compartment damper 114 is closed and the cooling fan 111 is stopped because the refrigerant remaining in the evaporator cooling duct 137 of the evaporator 106 evaporates, the temperature of the evaporator 106 approaches the air temperature of the refrigerating compartment 101, and heat exchange becomes difficult.

The state of the defrost heater 120 is switched from "OFF" to "ON". Energization of the defrost heater 120 is started, thereby defrosting also from the lower side of the evaporator 106. At this time, the compressor 105 is "ON", and the defrost heater 120 is also "ON".

By utilizing the latent heat of condensation of the refrigerant flowing through the evaporator heating pipe 138, the applied voltage is reduced from 100V (180W) to 50V (45W) in the present embodiment even if the capacity of the defrosting heater 120 is small. The capacity of the defrosting heater 120 varies according to the outside air temperature, the operation state, and the adhesion state of frost.

In the present embodiment, for example, when the outside air temperature is 32 ℃, the electric power of the compressor 105 is about 45W by heating using the latent heat of condensation of the refrigerant, and the capacity of the defrosting heater 120 is about 45W, so that the electric power used in defrosting is about 90W in total. This power is half of 180W when only the defrost heater 120 is used. This reduces the power consumption during defrosting and reduces the peak value of the electric power.

Next, at time T4, the state of the freezing compartment damper 112 is switched from "closed" to "open". The air in the cooling chamber 117 during defrosting is heated, but if there is no convection heat, it stagnates, and a temperature difference is generated above and below the evaporator 106. Therefore, by switching the state of the freezing compartment damper 112 to "open", a plurality of convection currents are generated from the inside of the freezing compartment 102 having a low temperature to the inside of the cooling compartment 117 having a high temperature during defrosting, thereby improving defrosting efficiency. In the present embodiment, the flow is "open", but the flow may be slightly open as long as a small amount of convection occurs.

The time T5 is a time when the temperature detected by the temperature sensor 115 reaches a predetermined temperature, and is a time when the refrigerator 100 determines that defrosting of the evaporator 106 has ended. At time T5, the state of the compressor 105 is switched from "ON" to "OFF", and the state of the 1 st mechanical room fan 116 is also switched from "ON" to "OFF". In addition, the state of the defrost heater 120 is switched from "ON" to "OFF".

Thereby, the operation of the defroster passage 152 is stopped, and the state is maintained from the time T5 to the time T7 until the pressure in the defroster passage 152 is substantially uniform. ON the other hand, the state of "ON" of the heating-side evaporator fan 134 is maintained from time T5 to time T6.

At this time, since the refrigerating chamber 101 is in a cooled state, by adjusting the time from the time T5 to the time T6, supercooling in the refrigerating chamber 101 can be suppressed. At this time, the time T6 is entered at the time when the temperature detected by the refrigerating chamber temperature sensor disposed in the refrigerating chamber 101 reaches the predetermined temperature. The same sensor as that for controlling the opening and closing of the refrigerating compartment damper 114 during the cooling operation is used for the refrigerating compartment temperature sensor.

Next, at time T6, the state of the heating-side evaporator fan 134 is switched from "ON (ON)" to "OFF (OFF)".

Next, at time T7, the state of the flow path switching valve 122 is switched from "defrost" to "cool" and maintained for a predetermined time until the pressure in the defrost path 152 and the cooling path 151 are substantially uniform, and then at time T8, the state of the compressor 105 is switched from "OFF" to "ON", and the operation of the cooling path 151 is started. Here, the reason for keeping the predetermined time is to prevent unpleasant noise from being generated due to rapid flow of the refrigerant when the flow path switching valve 122 is switched.

The state of the heating-side evaporator fan 134 is set to "ON" from time T5 to time T6 and from time T8 to time T9 in order to quickly raise the temperature of the heating-side evaporator 131 connected to the evaporator 106 via the suction pipe 126.

At time T8, the compressor 105 starts the operation of the cooling passage 151. After waiting for the predetermined time to the time T9 when the temperature of the evaporator 106 sufficiently drops, the state of the heating-side evaporator fan 134 is switched from "ON" to "OFF", and the state of the cooling fan 111 is switched from "OFF" to "ON".

At time T9, the refrigerator 100 shifts from the defrosting operation to the cooling operation.

Next, the flowchart of fig. 8 shows the processing performed by the refrigerator 100. Each step shown in the flowchart of fig. 8 is realized by a CPU (not shown) of the refrigerator 100 executing a control program stored in a memory (not shown) such as a ROM of the refrigerator 100. Although not shown in fig. 1, a control board including a CPU and a ROM is housed in the top surface 100d of the refrigerator 100.

In step 401, the CPU determines whether or not defrosting is performed. In the present embodiment, when the accumulation of the operation time of the compressor 105 reaches the predetermined time, after the lapse of the predetermined time since the completion of the previous defrosting, or when the external air temperature and the amount of frost adhering to the evaporator 106 due to the opening and closing of the doors 101a and 102a are large, the CPU determines that defrosting is performed, and the process proceeds to step 402. This operation corresponds to time T2 of fig. 7.

Next, in step 402, the CPU switches the flow path of the refrigerant to the defrost path 152. The CPU controls the flow path switching valve 122 to switch the flow path of the refrigerant from the cooling passage 151 to the defrosting passage 152. By switching the flow path of the refrigerant to the defrost path 152, the refrigerant heated by the 1 st heat exchanging portion 128 is supplied to the evaporator 106, and defrosting of the evaporator 106 is performed. In addition, defrosting by the defrosting path 152 is performed from the upper side of the evaporator 106. This operation corresponds to time T2 to T5 of fig. 7.

Next, in step 403, the CPU starts the operation of the defrosting heater 120. The CPU starts energization to the defrosting heater 120, thereby defrosting the evaporator 106. In addition, defrosting of the defrosting heater 120 is performed from the lower side of the evaporator 106. This operation corresponds to time T3 to time T5 in fig. 7.

Next, in step 404, the CPU determines whether or not defrosting is ended. In the present embodiment, when the temperature detected by the temperature sensor 115 reaches a predetermined temperature, the CPU determines that defrosting is completed, and stops the operation of the compressor 105 and the energization of the defrosting heater 120. The process proceeds to step 405. This operation corresponds to time T5 in fig. 7.

Next, in step 405, the CPU stops the operation of the compressor 105 and stops the energization of the defroster 120. After waiting for a predetermined time, the process proceeds to step 406 for the cooling operation.

Next, in step 406, the CPU controls the flow path switching valve 122 to switch the flow path of the refrigerant from the defrost path 152 to the cooling path 151 so as to perform the cooling operation after defrosting. After waiting for a predetermined time, the compressor 105 and the heating-side evaporator fan 134 are driven in advance.

Then, the CPU stops the heating-side evaporator fan 134, drives the cooling fan 111, and starts the air blowing, thereby starting the cooling operation of the refrigerator 100. This operation corresponds to time T7 to time T9 in fig. 7.

In the present embodiment, the steps shown in the flowchart of fig. 8 are described as being implemented by one CPU, but a configuration in which a plurality of CPUs cooperate may be employed.

(1-3. Effect, etc.)

As described above, in the present embodiment, the refrigerator 100 includes the refrigeration cycle 150 including at least the compressor 105, the 1 st condenser 107, the 2 nd condenser 123, and the evaporator 106. The refrigeration cycle 150 is branched into a cooling passage 151 that supplies the refrigerant to the evaporator 106 to generate cool air, and a defrosting passage 152 that heats the refrigerant and supplies the heated refrigerant to the evaporator 106 to defrost, on the downstream side of the 1 st condenser 107.

The refrigerant flowing through the cooling passage 151 is supplied to the evaporator 106 after passing through the 2 nd condenser 123, the refrigerant flowing through the defrost passage 152 is heated by heat exchange with a path through which the refrigerant is supplied from the compressor 105 to the 1 st condenser 107, the evaporator 106 thermally coupled to the defrost passage 152 is heated, and the refrigerant having dissipated heat in the defrost passage 152 is evaporated in the heating side evaporator 131 provided on the downstream side of the evaporator 106 and then returned to the compressor 105.

As described above, the refrigerator 100 includes the cooling passage 151 and the defrost passage 152 for defrosting the evaporator 106 by heating the evaporator by the condensation heat of the refrigerant in one refrigeration cycle 150. The refrigerant also branches into a cooling passage 151 and a defrost passage 152 on the downstream side of the 1 st condenser 107 near the liquid phase in the two-phase region of the refrigerant state. When defrosting, the refrigerator 100 is switched to the defrosting passage 152 side, and thus can suppress flow noise generated from the flow path switching valve 122 or the evaporator 106.

In the refrigeration cycle 150, a part of the high-temperature and high-pressure refrigerant discharged from the compressor 105 is liquefied in a state where the refrigerant in the condensation piping is close to the saturated liquid line, and the volume of the refrigerant is reduced. Therefore, in the two-phase region, the flow rate of the liquid-phase refrigerant is about 1/40 of the flow rate of the gas-phase refrigerant, and the flow rate of the refrigerant flowing through the flow path switching valve 122 is slow. Since the refrigerant discharged from the compressor 105 does not directly flow through the flow path switching valve 122, it is possible to suppress the generation of unpleasant sounds for the user.

In addition, since the refrigerant flowing through the defrost path 152 is heated by the high-temperature refrigerant discharged from the compressor 105 in the 1 st heat exchange portion 128 after flowing through the flow path switching valve 122, the state of the refrigerant is gasified from the two-phase region close to the liquid phase. In this state, the evaporator 106 is heated by the latent heat of condensation. In the refrigeration cycle 150, heat of the compressor 105 or the condenser after heat radiation can be used for defrosting.

Accordingly, not only the sensible heat of the refrigerant but also the latent heat of the two-phase region having a larger heat than the sensible heat can be utilized, and therefore, a large amount of heat can be used for heating as compared with the case where the sensible heat amount near the latter half of the liquid phase in the condensation process or after condensation is used for defrosting of the evaporator 106. An efficiency of about 3 times the waste heat of the compressor 105 can be obtained.

In the present embodiment, since the evaporator heating pipe 138 is directly and closely attached to the periphery of the evaporator 106, the temperature can be uniformly increased, and defrosting can be performed more efficiently than an indirect defrosting heater. That is, since the defrosting efficiency is also improved, 3 times the efficiency of the defrosting heater 120 can be obtained.

Therefore, if the defrosting heater 120 is 180W as an input to the refrigerator 100, the same capacity can be obtained at 60W in defrosting using the defrosting path 152 of the present embodiment, and thus power saving can be achieved. In addition, the peak electric power of the refrigerator 100 is an electric power peak value at the time of defrosting using the defrosting heater 120, and the present embodiment can also suppress the peak electric power at the time of defrosting.

That is, since the fluctuation of the power used can be suppressed, the power load can be adjusted by controlling the defrosting time or the like, for example, according to the fluctuation of the power demand in summer and the power consumption of other devices in the home, and the power supply can contribute to environmental protection.

In the conventional refrigerator, the defrosting heater 120 heats not only the evaporator 106 but also the cooling chamber 117 substantially at the time of defrosting. This is due to radiant heat from the defrost heater 120. In the present embodiment, when defrosting is performed using the defrosting passage 152, the low-power defrosting heater 120 is simultaneously energized in a mixed manner, whereby the defrosting time of the evaporator 106 can be shortened and defrosting in the cooling chamber 117 can also be performed.

Thus, even if the additional power of the defrosting heater 120 is subtracted, the effect of shortening the time is large, and thus a larger energy saving effect can be obtained. Further, since the defrosting time is shortened and the temperature rise time in the bank is also shortened, the amount of electricity consumption involved in sub-cooling after defrosting can also be reduced. Further, since the temperature rise of the refrigerating chamber 101 and the freezing chamber 102 is also suppressed, the temperature rise of the stored food is also suppressed, and the deterioration of freshness is also effectively suppressed.

The heating side evaporator 131 is disposed in the refrigerating temperature zone. The refrigerant circulation amount is controlled according to the rotation speed of the compressor 105, etc. in such a manner that the temperature of the heating side evaporator 131 located in the refrigerating chamber duct 113 is maintained at-25 to-10 c during defrosting. This temperature is equal to the cold air sent from the evaporator 106 during the cooling operation. Therefore, the refrigerating compartment 101 can be cooled by the heating side evaporator fan 134 located above by using the refrigerating compartment duct 113 at the time of cooling.

As a result, if the defrosting of the general refrigerator is performed, the compressor 105 is stopped at the time of defrosting, and therefore, if the amount of frost is large, the cooling may be stopped for about 60 minutes due to the defrosting. In this case, the temperature of the refrigerator compartment 101 also changes depending on the outside air temperature, and is usually about 4 ℃, but eventually rises to a temperature exceeding 10 ℃. Many fresh foods that are susceptible to temperature fluctuations, and foods that require refrigeration (below 10 ℃) that are also labeled in the food label, are stored in the refrigerator compartment 101. In the present embodiment, since defrosting can be performed while cooling the refrigerator compartment 101 without stopping the compressor 105, the temperature in the refrigerator is not increased even during defrosting, and a constant temperature state can be maintained.

That is, even when the temperature in the refrigerator compartment 101 fluctuates due to the refrigerator compartment temperature sensor and the refrigerator compartment damper 114 during the cooling operation, the temperature is kept at a constant temperature of approximately 4 ℃. Also, cooling is possible during defrosting, and the temperature can be kept constant, and approximately 4 ℃ which is the temperature in the refrigerator compartment 101 is kept, so that deterioration in food freshness can be suppressed.

In addition, the operation of the heating side evaporator fan 134 is controlled during defrosting. Thus, not only the periphery of the heating side evaporator 131 but also the whole interior of the container can be cooled, and therefore the temperature distribution in the container can be improved, and the quality can be improved.

In addition, the operation of the heating side evaporator fan 134 is controlled in accordance with the temperature detected by the refrigerator temperature sensor during defrosting. Specifically, the heating-side evaporator fan 134 can be stopped and the rotational speed can be increased or decreased.

In the present embodiment, the operation of the heating-side evaporator fan 134 is stopped at or below the threshold temperature during the period from time T2 to time T6 in fig. 7. The threshold temperature is 0 ℃. Thereby, supercooling of the temperature inside the refrigerator compartment 101 is avoided.

At this time, although there is concern about the backflow of the liquid to the compressor 105, it can be avoided by using an evaporator reservoir (not shown) after the heating side evaporator 131.

In addition, in the present embodiment, since the inside of the refrigerating chamber 101 can be cooled during defrosting, the required cooling capacity is reduced during sub-cooling after defrosting as compared with defrosting in which the compressor 105 is stopped and heating is performed using the defrosting heater 120. Since the temperature of the refrigerating chamber 101 is kept at a constant temperature during defrosting, power saving can be achieved by reducing the operation speed of the compressor 105, shortening the cooling time, and the like, by only sub-cooling the freezing chamber 102 after defrosting.

In addition, in the present embodiment, since low-temperature air is not discharged from the mechanical portion of the refrigerator, there is no concern that condensation may occur around the refrigerator. Further, since the cooling operation in the refrigerating chamber can be performed without stopping the compressor even during defrosting, the temperature fluctuation in the storage can be suppressed, and deterioration of quality of fresh food and the like can be suppressed.

(embodiment 2)

Next, embodiment 2 will be described with reference to fig. 9 and 10.

(2-1. Structure)

In fig. 9, the refrigerator 100 according to the present embodiment has a structure of the refrigerator 100 according to embodiment 1, and a two-way valve 125 is provided between the 2 nd condenser 123 and the 1 st throttle part 124.

(2-2. Operation)

Next, the operation and action of the defrosting operation of defrosting the evaporator 106 of the refrigerator 100 according to the present embodiment configured as described above will be described with reference to fig. 10.

Fig. 10 shows the passage of time from left to right.

The "open" of the two-way valve 125 means that the two-way valve 125 is open. In addition, "closed" of the two-way valve 125 means that the two-way valve 125 is closed.

The time T1 is a time when the refrigerator 100 shifts from the normal cooling operation to the defrosting operation. The timing of transition to the defrosting operation is, for example, a timing when the cumulative operation time of the compressor 105 has reached a predetermined time from the last defrosting time, a timing when a predetermined time has elapsed, or the like. At time T1, since it is assumed that the temperature of the freezing compartment 102 increases due to defrosting, the refrigerator 100 temporarily opens the freezing compartment damper 112, and the temperature of the freezing compartment 102 is reduced before defrosting starts.

At time T2, the state of the flow path switching valve 122 is switched from "cooling" to "defrosting". At time T2, the state of the freezing compartment damper 112 is switched from "open" to "closed", and the state of the refrigerating compartment damper 114 is switched from "closed" to "open".

Further, at time T2, the state of the heating-side evaporator fan 134 is changed from "OFF" to "ON". As a result, the refrigerant is heated by latent heat generated by condensation in the evaporator 106, and defrosting is started. Further, the refrigerant remaining in the evaporator cooling pipe 137 of the evaporator 106 is evaporated while cooling the refrigerating chamber 101, thereby suppressing the temperature rise of the refrigerating chamber 101 at the time of defrosting and preventing liquid backflow to the compressor 105.

At this time T2, the state of the two-way valve 125 is switched from "open" to "closed". By closing the two-way valve 125 at time T2, the inlet 123a and the outlet 123b of the 2 nd condenser 123 are closed, and the refrigerant is stored.

Accordingly, the amount of refrigerant suitable for the defrosting operation can be adjusted, and the dryness of the 1 st condenser 107 is set to 0 to 50%, so that the flow rate of the refrigerant in the flow path switching valve 122 can be suppressed, and occurrence of abnormal noise in the refrigerant flow can be prevented. This is because if the dryness of the 1 st condenser 107 exceeds 50%, the abnormal sound of the refrigerant flow in the flow path switching valve 122 becomes large as the refrigerant flow rate increases.

If the temperature is lower than 0% of the dryness of the 1 st condenser 107, i.e., if the temperature is supercooled, the enthalpy of the refrigerant is lost, and vaporization of the refrigerant in the 1 st heat exchange portion 128 becomes insufficient, resulting in a problem of a reduction in the amount of heat for defrosting the evaporator 106.

From time T5 to time T6, the state of the compressor 105 is switched from "ON" to "OFF", and the state of the 1 st mechanical room fan 116 is also switched from "ON" to "OFF". The state of the heating-side evaporator fan 134 is switched from "ON" to "OFF", and the state of the defrosting heater 120 is also switched from "ON" to "OFF". Thereby, the operation of the defroster passage 152 is stopped.

Thereafter, at time T7, the state of the flow path switching valve 122 is switched from "defrost" to "cool", and the two-way valve 125 is switched from "close" to "open". Further, the pressure in the defroster passage 152 is kept substantially uniform from the time T5 to the time T7 to prevent unpleasant noise from being generated by the rapid flow of the refrigerant when the flow path switching valve 122 or the two-way valve 125 is switched.

The state of the heating-side evaporator fan 134 is set to "ON" from time T5 to time T6 and from time T8 to time T9 in order to quickly raise the temperature of the heating-side evaporator 131 connected to the evaporator 106 via the suction pipe 126.

(2-2. Effect, etc.)

As described above, in the present embodiment, when the refrigerator 100 performs the defrosting operation, the two-way valve 125 provided between the 2 nd condenser 123 and the 1 st throttle portion 124 is closed, so that the refrigerant is stored in the 2 nd condenser 123, and the dryness of the 1 st condenser 107 is set to 0 to 50%.

Thus, the flow rate of the refrigerant is controlled, and the flow noise generated from the flow path switching valve 122 or the evaporator 106 can be further suppressed. Further, since the refrigerant is stored in the 2 nd condenser 123, there is no need to worry about the liquid back flow to the compressor 105.

In the present embodiment, the flow path switching valve 122 and the two-way valve 125 are simultaneously switched at time T2, but the present invention is not limited to this. For example, the two-way valve 125 may be switched from "open" to "closed" after a predetermined time period for switching the flow path switching valve 122 from "cooling" to "defrosting". In this way, the refrigerant storage amount of the 2 nd condenser 123 can be reduced. Conversely, the flow path switching valve 122 may be switched from "cooling" to "defrosting" after a predetermined time period for switching the two-way valve 125 from "open" to "closed". In this way, the refrigerant storage amount of the 2 nd condenser 123 can be increased. In this way, the optimum amount of the refrigerant can be adjusted according to various conditions such as the outside air temperature.

(other embodiments)

As described above, embodiments 1 and 2 are described as examples of the technology disclosed in the present application. However, the technique in the present invention is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, and the like are made. Further, the components described in embodiments 1 and 2 may be combined to form a new embodiment.

Accordingly, other embodiments are exemplified below.

In embodiments 1 and 2, the heat exchange method of the 1 st heat exchange portion 128 is performed by welding, but is not limited thereto, from the viewpoint of cost and simplicity. For example, in the laser processing method or the like, a pipe having a 8-shaped cross section in which the pipes are mechanically abutted against each other may be used. A double pipe may be used in which a pipe through which the refrigerant discharged from the 2 nd throttle portion 127 flows is disposed inside a pipe through which the refrigerant is supplied from the compressor 105 to the 1 st condenser 107.

The heat exchange method is not limited to welding, and there is a method in which the pipe is communicated with the inside of the compressor 105 to evaporate the refrigerant in order to use the latent heat of condensation of the refrigerant. It is possible to obtain much heat higher than the condensing temperature and to improve the heating efficiency of the evaporator heating pipe 138.

The compressor 105 is substantially an iron block, and has a weight of about 6 to 7 kg. Since the sensible heat of the weight portion can be utilized by heat exchange with the compressor 105, the same heating efficiency can be obtained with a short heat exchange length, and a compact structure can be realized.

In addition, the effect of heat exchange with the condenser is also great. The capacity-adjusting condenser 133 uses a fin tube type similar to the evaporator 106, and uses a part of the internal piping as the defrost path 152, so that heat exchange can be performed by the fins. By disposing the piping of the cooling passage 151 and the piping of the defrost passage 152 in one condenser, heat exchange can be effectively performed.

By making the flow direction of the refrigerant in each pipe opposite to each other, the temperature difference increases, and heat exchange can be performed efficiently. Since the inlet of the capacity-adjusting condenser 133 is a gas phase region before receiving the pipe pressure loss during condensation, the enthalpy at the h point in fig. 4B increases, and the heating capacity increases, and the defrosting efficiency increases.

In embodiments 1 and 2, small diameter pipes are used for the 2 nd and 3 rd throttle portions 127 and 129. The inner diameter is about 0.5-1.0 mm, and the length is about 2000 mm. Of course, an expansion valve capable of linearly controlling the flow rate or a fixed orifice valve capable of stepwise controlling the flow rate may be used. In this case, the structure using the small diameter pipe is inexpensive and simple, and the commodity cost can be controlled by reducing the manufacturing cost and the process man-hour.

Further, if the pipe at the inlet portion of the 1 st heat exchange portion 128 is formed in a contracted pipe shape instead of the small diameter pipe of the 2 nd throttle portion 127, the number of connection portions and components can be reduced, and a greater cost advantage can be obtained.

In embodiments 1 and 2, the fins 139 constituting the evaporator 106 are divided fins. In the divided fins, the number of fins increases, and therefore the number of steps for attaching the fins 139 needs to be increased in the manufacturing process of the evaporator 106.

Therefore, the fin 139 integrated in the up-down direction may be used. Accordingly, the number of fins 139 attached to the evaporator 106 can be reduced, and therefore, productivity can be improved and cost can be reduced by reducing the number of steps.

In this case, if the mounting portion of the evaporator heating pipe 138 is notched in advance on the fin 139, the adhesion with the evaporator heating pipe 138 improves, and the heat exchange efficiency improves.

The evaporator cooling pipe 137 of the evaporator 106 in the above embodiments 1 and 2 is a pipe whose inside is called a bare pipe and is not processed. Therefore, for example, a grooved pipe may be used to increase the heat transfer rate in the pipe. The grooved tube has a tube composed of straight grooves or spiral grooves, and the performance of the evaporator 106 can be improved by using the grooved tube, thereby further achieving energy saving.

The evaporator cooling tube 137 of the evaporator 106 in embodiments 1 and 2 is made of aluminum. In view of cost reduction due to an increase in material cost in recent years, aluminum is often used, but copper may be used. In this case, the heat transfer rate is improved, and therefore, the heat exchange efficiency between the inside and outside of the tube is improved, and energy saving is further achieved.

In embodiments 1 and 2, the heating side evaporator 131 is of the fin tube type similar to the evaporator 106, but a structure may be adopted in which a cold storage material is combined with the heating side evaporator 131. For example, resin Insert molded constructions and external unit, microchannel evaporators may also be employed.

By filling the cold storage material in the portion or the microchannel in contact with the heating-side evaporator 131, the cold and heat generated by the heating-side evaporator 131 can be stored in the cold storage material. Accordingly, after defrosting is completed, the refrigerating chamber 101 can be cooled by the cold storage material, and thus energy saving is further achieved. In addition, when the outside air temperature of the refrigerator compartment 101 is low and the influence of heat from the outside is small, the temperature of the refrigerator compartment 101 is rapidly cooled in the defrosting described in the above embodiment.

For example, when the temperature of the refrigerating chamber 101 falls below the threshold value, the rotational speed of the heating-side evaporator fan 134 is reduced or stopped, the rotational speed of the compressor 105 is reduced, or the like, to prevent backflow of the liquid sucked into the compressor 105, but the cold and heat can be stored by the cold storage material. Can be used for cooling of the refrigerating chamber 101 after defrosting.

In embodiments 1 and 2, heat exchange is also possible between the small diameter pipe of the 3 rd throttle part 129 and the heating side suction pipe 132 as a suction path to the compressor 105. Accordingly, not only the liquid refrigerant that has not evaporated in the heating-side evaporator 131 but also the liquid refrigerant is prevented from entering the suction pipe 126 due to evaporation, and in fig. 4B, the change from the point j to the point k is changed from isenthalpic to the obliquely left. Since this amount of change corresponds to the enthalpy difference from the outlet of the heating side evaporator 131 to the L point, the enthalpy difference from the k point to the L point increases, and the cooling effect in the defroster passage 152 increases. Therefore, the cooling capacity of the refrigerating chamber 101 is improved.

Industrial applicability

The present invention can suppress the generation of unpleasant sounds for users and can reduce the amount of sub-cooling after defrosting, and therefore can be applied to household refrigerators, freezers, commercial refrigerators, freezers.

Description of the reference numerals

100 refrigerator

100a separator

100b frame

100c outer wall surface

100d top surface

101. Refrigerating chamber

101a, 102a door

102 freezing chamber

103 1 st mechanical room

104 nd mechanical chamber

105 compressor

106 evaporator

107 st condenser 1

108 partition wall

109 nd mechanical room fan

110 evaporating dish

111 cooling fan

112 freezing chamber windshield

113 refrigerating chamber pipeline

114 refrigerator compartment windshield

115 temperature sensor

116 st mechanical room fan

117 cooling chamber

119 refrigerating chamber return pipeline

120 defrosting heater

121 dryer

122 flow path switching valve

123 2 nd condenser

123a inlet

123b outlet

124 st throttle part 1

125 two-way valve

126 suction pipe

127 nd throttle part

128 1 st heat exchange portion

128a inlet portion

128b outlet

129 3 rd throttle part

130 multistage expansion circuit

131 heating side evaporator

132 heating side suction pipe

Condenser for 133 capacity adjustment

134 heating side evaporator fan

137 evaporator cooling tube

138 evaporator heating pipe

139 fin

140 end plate

141 evaporator liquid storage device

143 evaporator cooling inlet

144 evaporator cooling outlet

145 evaporator heating inlet

146 evaporator heating outlet

150 refrigeration cycle

151 cooling passage

152 defrost path.

Claims (5)

1. A refrigerator is characterized in that,

in a refrigerator having a refrigeration cycle including at least a compressor, a 1 st condenser, a 2 nd condenser, and an evaporator,

the refrigeration cycle branches into two paths on the downstream side of the 1 st condenser:

a cooling passage for supplying a refrigerant to the evaporator to generate cool air; and

a defrosting path for defrosting by heating the refrigerant and supplying the heated refrigerant to the evaporator,

the refrigerant flowing through the cooling passage is supplied to the evaporator after passing through the 2 nd condenser,

the refrigerant flowing through the defrost path is heated by heat exchange with a path for supplying the refrigerant from the compressor to the 1 st condenser, and the evaporator thermally coupled to the defrost path is heated,

the refrigerant having dissipated heat in the defrost path is evaporated in a heating side evaporator provided downstream of the evaporator and returned to the compressor.

2. The refrigerator of claim 1, wherein,

The heating side evaporator is disposed in a refrigerating temperature zone.

3. A refrigerator according to claim 1 or 2, wherein,

a heating side evaporator fan is disposed above the heating side evaporator, and the heating side evaporator fan is operated during defrosting.

4. The refrigerator of claim 3, wherein,

and a refrigerating chamber temperature sensor for detecting the temperature of the refrigerating chamber, wherein the operation of the heating side evaporator fan is stopped when the refrigerating chamber temperature sensor of the refrigerating temperature zone in defrosting is below a threshold temperature.

5. The refrigerator according to any one of claims 1 to 4, wherein,

a cold storage material is combined in the heating side evaporator.

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