Patent ID: 12188699

DETAILED DESCRIPTION

Referring toFIGS.1to4, a refrigerator10may include a cabinet11which forms a storage compartment. The storage compartment may include a refrigerator compartment20and a freezer compartment30. For example, the refrigerator compartment20may be disposed at an upper side of the freezer compartment30. However, positions of the refrigerator compartment20and the freezer compartment30are not limited to these configurations. The refrigerator compartment20and the freezer compartment30may be divided by a partition wall28.

The refrigerator10may include a refrigerator compartment door25which is configured to open and close the refrigerator compartment20, and a freezer compartment door35which is configured to open and close the freezer compartment30. The refrigerator compartment door25may be hinge-coupled to a front of the cabinet11and may be formed to be rotatable, and the freezer compartment door35may be formed in a drawer type to be withdrawn forward.

Based on the cabinet11ofFIG.1, a direction at which the refrigerator compartment door25is located is defined as a “front side”, and an opposite direction thereof is defined as a “rear side”, and a direction toward a side surface of the cabinet11is defined as a “lateral side”.

The cabinet11may include an outer case12which forms an exterior of the refrigerator10, and an inner case13which is disposed inside the outer case12and forms at least a part of an inner surface of the refrigerator compartment20or the freezer compartment30. The inner case13includes a refrigerator compartment side inner case which forms the inner surface of the refrigerator compartment20, and a freezer compartment side inner case which forms the inner surface of the freezer compartment30.

A panel15is provided at a rear surface of the refrigerator compartment20. The panel15may be installed at a position which is spaced forward from a rear of the refrigerator compartment side inner case. A refrigerator compartment cooling air discharge part22for discharging cooling air to the refrigerator compartment20is provided at the panel15. For example, the refrigerator compartment cooling air discharge part22may be formed of a duct, and may be disposed to be coupled to an approximately central portion of the panel15.

A freezer compartment side panel may be installed at a rear wall of the freezer compartment30, and a freezer compartment cooling air discharge part for discharging the cooling air to the freezer compartment30may be formed at the freezer compartment side panel.

An installation space in which a first evaporator130is installed is formed at a space between the panel15and a rear of the inner case13. An installation space in which a second evaporator150is installed may be formed at a space between the panel and a rear of the freezer compartment side inner case.

The refrigerator10may include a plurality of evaporators130and150which cool the refrigerator compartment20and the freezer compartment30, respectively. The plurality of evaporators130and150include the first evaporator130which is configured to cool the refrigerator compartment20, and the second evaporator150which is configured to cool the freezer compartment30. The first evaporator130may be referred to as a “refrigerator compartment evaporator”, and the second evaporator150may be referred to as a “freezer compartment evaporator”.

The refrigerator compartment20is disposed at an upper side of the freezer compartment30, and as illustrated inFIG.2, the first evaporator130may be disposed at an upper side of the second evaporator150.

The first evaporator130may be disposed at a rear wall of the refrigerator compartment20, i.e., a rear side of the panel15, and the second evaporator150may be disposed at a rear wall of the freezer compartment30, i.e., a rear side of the freezer compartment side panel. The cooling air generated at the first evaporator130may be supplied to the refrigerator compartment20through the refrigerator compartment cooling air discharge part22, and the cooling air generated at the second evaporator150may be supplied to the freezer compartment30through the freezer compartment cooling air discharge part.

The first evaporator130and the second evaporator150may be hooked to the inner case13. For example, the second evaporator150includes hooks162and167(referring toFIG.7) which are hooked to the inner case13.

The refrigerator10may include a plurality of devices for driving a refrigeration cycle. The refrigeration cycle includes a first refrigeration cycle (hereinafter, referred to as first cycle) and a second refrigeration cycle (hereinafter, referred to as second cycle). The first cycle is understood as a cycle which has an evaporation pressure relatively high for cooling a refrigerator compartment. On the other hand, the second cycle is understood as a cycle which has an evaporation pressure relatively low for cooling a freezer compartment.

Specifically, the first cycle of the refrigerator10includes a first compressor101which compresses a refrigerant, a first condenser111which condenses the refrigerant compressed in the first compressor101, a first expansion device131which depressurizes the refrigerant condensed in the first condenser111, and a first evaporator130which evaporates the refrigerant depressurized in the first expansion device131. The refrigerant which circulates in the first cycle may be referred to as “a first refrigerant”. The first evaporator130includes a refrigerator compartment evaporator which cools the refrigerator compartment20, and the first expansion device131may include a capillary tube.

The first cycle of the refrigerator10further includes a fan which is provided at one side of a heat exchanger to blow air. The fan includes a first condenser fan112which is provided at one side of the first condenser111, and a first evaporator fan130awhich is provided at one side of the first evaporator130

The first cycle of the refrigerator10further includes a first refrigerant pipe101awhich connects the first compressor101, the first condenser111, the first expansion device131, and the first evaporator130and guides a flow of the refrigerant.

The second cycle of the refrigerator10includes a second compressor102which compresses a refrigerant, a second condenser115which condenses the refrigerant compressed in the second compressor102, a second expansion device135which depressurizes the refrigerant condensed in the second condenser115, and a second evaporator150which evaporates the refrigerant depressurized in the second expansion device135. The refrigerant which circulates in the second cycle may be referred to as “a second refrigerant”, the second refrigerant is not mixed with the first refrigerant. The second evaporator150includes a freezer compartment evaporator which cools the freezer compartment30. The second expansion device135may include a capillary tube.

The second cycle of the refrigerator10further includes a fan which is provided at one side of a heat exchanger to blow air. The fan includes a second condenser fan116which is provided at one side of the second condenser115, and a second evaporator fan150awhich is provided at one side of the second evaporator150.

The second cycle of the refrigerator10further includes a second refrigerant pipe102awhich connects the second compressor102, the second condenser115, the second expansion device135and the second evaporator150and guides a flow of the refrigerant.

The refrigerator10further includes a first hot gas path145extended from an outlet side pipe of the first compressor101toward the second evaporator150side and coupled to the second evaporator150. The first hot gas path145supplies a high temperature refrigerant compressed in the first compressor101to the second evaporator150to defrost the second evaporator150.

A valve unit140may be installed at the outlet side pipe of the first compressor101. The first hot gas path145, which is connected to the valve unit140, extends to the second evaporator150, and may be configured to be connected to the first refrigerant pipe101avia the second evaporator150.

The first refrigerant pipe101aincludes a combination part105to which the first hot gas path145is connected. That is, one side edge of the first hot gas path145is connected to a second outlet part143of the valve unit140, and the other side edge of the first hot gas path145may be connected to the combination part105of the first refrigerant pipe101a.

The valve unit140includes a three-way valve having an inlet part141in which the refrigerant is introduced, and two outlet parts142and143from which the refrigerant is discharged. The inlet part141is connected to a valve inlet pipe103provided at an outlet side of the first compressor101. The refrigerant compressed in the first compressor101may be introduced into the valve unit140via the valve inlet pipe103and the inlet part141.

The two outlet parts142and143includes a first outlet part142which is configured to guide the refrigerant introduced into the valve unit140through the inlet part141to be discharged to a valve outlet pipe104. That is, the first outlet part142may be connected to the valve outlet pipe104. The valve outlet pipe104is extended from the first outlet part142to the first condenser111.

The two outlet parts142and143further includes the second outlet part143which is configured to guide the refrigerant introduced into the valve unit140to be discharged to the first hot gas path145. That is, the second outlet part143may be connected to the first hot gas path145. In accordance with the operation mode of the refrigerator, a refrigerant introduced into the inlet part141of the valve unit140may be discharged to any one of the first outlet part142and the second outlet part143.

Referring toFIG.5, when the refrigerator10is operated in a normal mode, first operating mode, the valve unit140may be controlled in a predetermined operation mode. The normal mode may be understood as an operation mode which is performed without a defrosting operation of the first evaporator130or the second evaporator150, and thus the refrigerator compartment20or the freezer compartment30is cooled.

For example,FIG.5illustrates a state in which a simultaneous cooling of the refrigerator compartment20and the freezer compartment30is performed by driving all of the first and second cycle of the refrigerator10. When only a cooling of the refrigerator compartment20is required only a driving of the first compressor101may be performed. On the other hand, when only a cooling of the freezer compartment30is required only a driving of the second compressor102may be performed.

Hereinafter, a case in which the simultaneous cooling of the refrigerator compartment and the freezer compartment is performed is described as an example. In the normal mode operation of the refrigerator, the first cycle may be operated. Specifically, the first refrigerant compressed in the first compressor101is introduced into the inlet part141of the valve unit140. The valve unit140may be controlled in the first operation mode. Specifically, the first outlet part142of the valve unit140is opened and the second outlet part143of the valve unit140is closed. Therefore, the first refrigerant introduced into the valve unit140through the inlet part141may be discharged to the first outlet part142, and the flow of the first refrigerant through the first hot gas path145is restricted.

The first refrigerant discharged from the valve unit140is introduced into the first condenser111via the valve outlet pipe104, depressurized in the first expansion device131, and introduced into the first evaporator130. The first refrigerant is evaporated in the first evaporator130and cool air generated in this process may be supplied to the refrigerator compartment20. The first refrigerant passing through the first evaporator130may be suctioned into the first compressor101and compressed.

In the normal mode operation of the refrigerator10, the second cycle may be operated. Specifically, the second refrigerant compressed in the second compressor102is condensed in the second condenser115, depressurized in the second expansion device135, and introduced into the second evaporator150. The second refrigerant is evaporated in the second evaporator150and cool air generated in this process may be supplied to the freezer compartment30. The second refrigerant passing through the first evaporator130may be suctioned into the second compressor102and compressed.

Referring toFIG.6, when the refrigerator10is operated in a freezer compartment defrosting mode, that is a second operation mode, the valve unit140may be controlled in the second operation mode. Specifically, in the freezer compartment defrosting mode of the refrigerator10, the first refrigerant compressed in the compressor101is introduced into the inlet part141of the valve unit140. The first outlet part142of the valve unit140is closed, and the second outlet part143of the valve unit140is opened. Accordingly, the first refrigerant introduced into the valve unit140through the inlet part141and may be discharged through the second outlet part143. The first refrigerant discharged from the valve unit140flows in the first hot gas path145and passes through the second evaporator150.

In the process of the first refrigerant of the first hot gas path145passing through the second evaporator150, the ice formed at the second evaporator150may be removed. The refrigerant passing through the second evaporator150is introduced into the first refrigerant pipe101athrough the first combination part105, and depressurized in the first expansion device131and may flow into the first evaporator130. At this time, by the closed first outlet part142, the refrigerant may be restricted from flowing into the valve unit140from the first combination part105.

The refrigerant is evaporated in the first evaporator130and cool air generated in this process may be supplied to the refrigerator compartment20. The refrigerant passing through the first evaporator130is suctioned into the first compressor101and may be compressed. Meanwhile, in the process of defrosting the second evaporator150, a circulation of the second refrigerant through the second cycle is stopped, that is, the second compressor102is not driven. According to such an action, in the process of defrosting the second evaporator150, a cooling of the refrigerator compartment20may be performed through an operation of the first evaporator130, and thus cooling performance of the refrigerator may be improved.

The defrosting of the first evaporator130may be performed through an operation of the first evaporator fan130a. When the two cycles are performed, an evaporation temperature of the first evaporator130disposed at a high pressure side is formed relatively higher. For example, the evaporation temperature of the first evaporator130may be formed within a range of −5° C. to 0° C. Therefore, an ice forming amount of the first evaporator130may be small, and a frosting degree may not be serious.

Instead of using a separate high temperature refrigerant (hot gas), the cooling air in the refrigerator compartment20may be supplied to the first evaporator130, and may perform the defrosting operation of the first evaporator130(natural defrosting). At this time, a driving of the first compressor101may be stopped. For an operation of the second cycle, the second compressor102is driven, a supplying of a cool air to the freezer compartment30may be performed.

According to such an action, the cooling operation of the freezer compartment30may be performed through the operation of the second cycle forming a separate cycle even when the defrosting operation of the first evaporator130is performed, and thus the cooling performance of the refrigerator may be prevented from being degraded. In comparison with the defrosting operation using the hot gas, the temperature of the first evaporator130may be kept relatively low through the natural defrosting operation, and thus when the first evaporator130is operated after the defrosting operation is terminated, evaporation performance may be improved.

Referring toFIG.11, the second evaporator150may include a plurality of refrigerant pipes151and170through which refrigerant having different phases from each other flows. The second evaporator may include a fin155which is coupled to the plurality of refrigerant pipes151and170and that is configured to increase a heat exchange area between the refrigerant and a fluid.

Specifically, the plurality of refrigerant pipes151and170includes a first pipe151through which the refrigerant depressurized in the second expander104aflows, and a second pipe170through which the refrigerant condensed in the condenser102is supplied. The second pipe170forms at least a part of the first hot gas path105, and may be referred to as a “hot gas pipe”.

The second refrigerant flowing through the second pipe170may have a temperature higher than that of the refrigerant flowing through the first pipe151.

The second evaporator150further includes coupling plates160and165which fix the first pipe151and the second pipe170.

Specifically, a plurality of coupling plates160and165may be provided at both sides of the second evaporator150. The coupling plates160and165include a first plate160which supports one side of each of the first pipe151and the second pipe170, and a second plate165which supports the other side of each of the first pipe151and the second pipe170. The first and second plates160and165may be disposed to be spaced apart from each other.

The first pipe151and the second pipe170may be formed to be bent in one direction from the first plate160toward the second plate165and the other direction from the second plate165toward the first plate160.

The first and second plates160and165serve to fix both sides of the first pipe151and the second pipe170, and are configured to prevent shaking of the first pipe151and the second pipe170. For example, the first pipe151and the second pipe170may be disposed to pass through the first and second plates160and165.

Each of the first and second plates160and165has a plate shape which extends longitudinally, and may have through-holes166aand166bthrough which at least parts of the first pipe151and170pass. Specifically, the through-holes166aand166binclude a first through-hole166athrough which the first pipe151passes, and the second through-hole166bthrough which the second pipe170passes.

The first pipe151may be disposed to pass through the first through-hole166aof the first plate160, to extend toward the second plate165, and to pass through the first through-hole166aof the second plate165, and then a direction thereof may be changed so as to extend again toward the first plate160.

The second pipe170may be disposed to pass through the second through-hole166bof the first plate160, to extend toward the second plate165, and to pass through the second through-hole166bof the second plate165, and then a direction thereof may be changed so as to extend again toward the first plate160.

The second evaporator150includes a first inlet part151awhich guides the introduction of the refrigerant into the first pipe151, and a first outlet part151bwhich guides the discharge of the refrigerant flowed through the first pipe151. The first inlet part151aand the first outlet part151bform at least a part of the first pipe151. For example, a two-phase refrigerant which is depressurized in the second expansion device135is introduced into the second evaporator150through the first inlet part151a, evaporated during a heat exchange process, and then discharged from the second evaporator150through the first outlet part151b.

The evaporator150includes a second inlet part171which guides the introduction of the refrigerant into the second pipe170, and a second outlet part172which guides the discharge of the refrigerant flowed through the second pipe170. The second inlet part171and the second outlet part172form at least a part of the second pipe170.

For example, in the defrosting mode of the second evaporator150, i.e., in the second operating mode, the high temperature first refrigerant compressed in the first compressor101flows in the first hot gas path145and is introduced into the second evaporator150through the first inlet part171. The first refrigerant removes the ice generated at the second evaporator150during the heat exchange process at the second evaporator150, and then discharged from the second evaporator150through the second outlet part172.

A plurality of fins155are provided to be spaced apart from each other, and the first pipe151and the second pipe170are disposed to pass through the plurality of fins155. Specifically, the fins155may be disposed to vertically and horizontally form a plurality of rows.

The coupling plates160and165include the hooks162and167which are coupled to the inner case13. The hooks162and167are disposed at upper portions of the coupling plates160and165, respectively. Specifically, the hooks162and167include a first hook162which is provided at the first plate160, and a second hook167which is provided at the second plate165.

The first and second support parts163and168through which the second pipe170passes are formed at the coupling plates160and165, respectively. The first and second support parts163and168are disposed at lower portions of the coupling plates160and165, respectively. Specifically, the first and second support parts163and168include a first support part163which is provided at the first plate160, and a second support part168which is provided at the second plate165.

The second pipe170includes an extension part175which forms a lower end of the evaporator150. Specifically, the extension part175is formed to extend downward further than a lowermost fin155of the plurality of fins155. The extension part175is located inside a water collection part180(referring toFIG.11) which will be described later, and may supply heat to remaining frost in the water collection part180. Defrosted water may be drained to a machinery compartment50.

Due to the extension part175, the second pipe170may have a shape which is inserted into the first and second support parts163and168and extends to a central portion of the evaporator150. That is, due to a configuration in which the second pipe170passes and extends through the first and second support parts163and168, the extension part175may be stably supported by the evaporator150.

The first pipe151and the second pipe170may be installed to pass through the plurality of fins155. The plurality of the fins155may be disposed to be spaced apart from each other at a predetermined distance. Specifically, each of the fins155includes a fin body156having an approximately quadrangular plate shape, and a plurality of through-holes157and158which are formed at the fin body156and through which the first pipe151and the second pipe170pass. The plurality of through-holes157and158includes a first through-hole157through which the first pipe151passes, and a second through-hole158through which the second pipe170passes. The plurality of through-holes157and158may be disposed in one row.

An inner diameter of the first through-hole157may have a size different from that of an inner diameter of the second through-hole158. For example, the inner diameter of the first through-hole157may be formed larger than that of the second through-hole158. In other words, an outer diameter of the first pipe151may be formed larger than that of the second pipe170. This is because the first pipe151guides the flow of the refrigerant which performs an innate function of the evaporator150, and thus a relatively large flow rate of the refrigerant is required. However, since the second pipe170guides the flow of the high temperature refrigerant for a predetermined time only when the defrosting operation of the evaporator150is required, a relatively small flow rate of the refrigerant is required.

Referring toFIG.9, a refrigerator10amay include a valve unit140ainstalled on an outlet side pipe of the first condenser111and a first hot gas path145aextended to the second evaporator150from the valve unit140a. The first hot gas path145amay be connected to a combination part105avia the second evaporator150. The combination part105amay be located at a valve outlet pipe of the valve unit140a. The valve outlet pipe may be extended to the first expansion device131from the valve unit140a.

When a freezer compartment defrosting mode operation of the refrigerator10a, the first refrigerant having passed through the first condenser111is introduced to the valve unit140aand flows in the first hot gas path145a. And the first refrigerant of the first hot gas path145aflows to the second evaporator150, removes the ice formed at the second evaporator150and may flow to the combination part105a. The first refrigerant is introduced to the first evaporator130and evaporates, and cool air generated in this process may be supplied to the to the refrigerator compartment20.

Referring toFIGS.10and11a refrigerator10bmay include a plurality of devices for driving a refrigerating cycle. The refrigerating cycle includes a first cycle and a second cycle.

Specifically, the first cycle of the refrigerator10bincludes a first compressor201for compressing a refrigerant, a first condenser211condensing the refrigerant compressed in the first compressor201, a first expansion device231for depressurizing the refrigerant condensed in the first condenser211and a first evaporator230for evaporating the refrigerant depressurized in the first expansion device231. A refrigerant circulating in the first cycle may be named as a first refrigerant. The first evaporator230includes a refrigerator compartment evaporator for refrigerating the refrigerator compartment20. The first expansion device231may include a capillary tube.

The first cycle of the refrigerator10bfurther includes an air blowing fan provided on one side of the heat exchanger and blowing the air. The air blowing fan includes a first condensation fan212provided on one side of the first condenser211and a first evaporation fan230aprovided on one side of the first evaporator230.

The first cycle of the refrigerator10bfurther includes a first refrigerant pipe201aconnecting the first compressor201, the first condenser211, the first expansion device231and the first evaporator230and guiding the flow of the refrigerant.

The second cycle of the refrigerator10bincludes a second compressor202for compressing a refrigerant, a second condenser215condensing the refrigerant compressed in the second compressor202, a plurality of expansion devices235and236for depressurizing the refrigerant condensed in the second condenser215and a plurality of evaporators250and260for evaporating the refrigerant depressurized in the plurality of expansion devices235and236. A refrigerant circulating in the second cycle may be named as a second refrigerant and the second refrigerant is understood as a refrigerant immiscible with the first refrigerant.

The plurality of evaporators250and260includes a second evaporator250and a third evaporator260connected in series. The second evaporator250includes a freezer compartment evaporator for refrigerating the freezer compartment30. The third evaporator260includes an evaporator for supplying the cool air to a switching chamber. The switching chamber may act as freezer compartment or fresh compartment. The fresh compartment may be maintained at a slightly lower temperature than the temperature of the refrigerator compartment, and may be used to store meat or fish. For example, the temperature of the refrigerator compartment is formed in a range of 0 to 5° C., and the temperature of the fresh compartment may be formed in a range of −1 to 2° C.

The plurality of expansion devices235and236includes a second expansion device235installed on an inlet side of the third evaporator260and a third expansion device236installed in a bypass path290. The second expansion device235may be installed between a third valve unit280and the third evaporator260. For example, the second and third expansion devices235and236may include a capillary tube.

The second cycle of the refrigerator10bfurther includes an air blowing fan provided on one side of the heat exchanger and blowing the air. The air blowing fan includes a second condensation fan216provided on one side of the second condenser215, a second evaporation fan250aprovided on one side of the second evaporator250and a third evaporation fan260aprovided on one side of the third evaporator260.

The second cycle of the refrigerator10bfurther includes a second refrigerant pipe202aconnecting the second compressor202, the second condenser215, the second and third expansion devices235and236and the second and third evaporators250and260, and guiding the flow of the refrigerant.

The refrigerator10bfurther includes a first hot gas path245extended from an outlet side pipe of the first compressor201toward the second evaporator250. The hot gas path245supplies a high temperature refrigerant compressed in the first compressor201to the second evaporator250, so that defrosting of the second evaporator250is made.

A first valve unit240is installed at the outlet side pipe of the first compressor201. The first hot gas path245may be configured to be connected to the first valve unit240, extended to the second evaporator250, and connected to the first refrigerant pipe201avia the second evaporator250.

The first refrigerant pipe201aincludes a first combination part205to which the first hot gas path245is connected. That is, one end of the first hot gas path245is connected to a second outlet part of the first valve unit240, and the other end may be connected to the first combination part205of the first refrigerant pipe201a.

The first valve unit240includes a three-way valve having an inlet part in which the refrigerant is introduced and two outlet parts from which the refrigerant is discharged.

For defrosting of the third evaporator260, the refrigerator10bfurther includes a second hot gas path246supplying the refrigerant having passed through the second condenser215to the third evaporator260.

The refrigerator10bfurther includes a second valve unit270installed on an outlet side pipe of the second condenser215. The second valve unit270includes a four-way valve. Specifically, the second valve unit270includes two inlet parts271and274and two outlet parts272and273.

The two inlet parts271and274include a first inlet part271connected to a valve inlet pipe203. The valve inlet pipe203is connected to an outlet side of the second condenser215. Therefore, the refrigerant condensed in the second condenser215may be introduced into the second valve unit270through the first inlet part271via the valve inlet pipe203.

The two inlet parts271and274include a second inlet part274connected to the second hot gas path246. Specifically, the second hot gas path246includes an evaporator introduction pipe246aextended from the second valve unit270to the third evaporator260and guiding introduction of the refrigerant toward the third evaporator260, and an evaporator discharge pipe246bextended from the third evaporator260to the second valve unit270and guiding the discharge of the refrigerant from the third evaporator260.

The evaporator discharge pipe246bis connected to the second inlet part274. Therefore, the refrigerant supplied to the third evaporator260and performed a defrosting may be introduced into the second valve unit270through the second inlet part274via the evaporator discharge pipe246b.

The two outlet parts272and273includes a first outlet part272connected to a valve outlet pipe204. The valve outlet pipe204extends toward the third valve unit280from the first outlet part272. Therefore, the refrigerant discharged from the second valve unit270through the first outlet part272may be introduced into the third valve unit280via the valve outlet pipe204.

The two outlet parts272and273further include a second outlet part273connected to the evaporator introduction pipe246a. Therefore, the refrigerant discharged from the second valve unit270through the second outlet part273may be introduced to the third evaporator260via the evaporator introduction pipe246a.

The third valve unit280is installed at an outlet side of the second valve unit270. The third valve unit280includes an inlet part281connected to the valve outlet pipe204and guiding the introduction of the refrigerant. Therefore, the refrigerant discharged through the first outlet part272of the second valve unit270may be introduced to the third valve unit280through the inlet part281.

The third valve unit280further includes a first outlet part282guiding the refrigerant to the second expansion device235. The first outlet part282is connected to a connection pipe207. The connection pipe207is extended to the second expansion device235from the first outlet part282of the third valve unit280. The second expansion device235is installed on the inlet side of the third evaporator260and may depressurize the refrigerant which will be introduced to the third evaporator260.

The third valve unit280further includes a second outlet part283guiding the refrigerant to the bypass path290. The bypass path290is connected to the second outlet part283and extended toward an inlet side of the second evaporator250and understood as a pipe which is bypassing the third evaporator260.

In a preset operation mode of the refrigerator10b, the refrigerant introduced into the third valve unit280may be introduced into the second evaporator250via the bypass path290.

The second refrigerant pipe202aincludes a second combination part295with which the bypass path290is combined. The second combination part295may be located in a pipe connecting the second evaporator250and third evaporator260. That is, one side part of the bypass path290may be connected to the third valve unit280and the other side part may be connected to the second combination part295.

First referring toFIG.12, during a normal mode operation as a first operation mode of the refrigerator10b, the first valve unit240may be controlled in a predetermined operating mode. The “normal mode” may be understood as an operation mode which makes the cooling of the refrigerator compartment20, the freezer compartment30or the switching chamber without a defrosting operation of the first, second and third evaporators230,250and260.

During the normal mode operation of the refrigerator10b, the first cycle may be operated. Specifically, the first refrigerant compressed in the first compressor201is introduced to the inlet part of the first valve unit240. The first valve unit240may be controlled in a first operating mode.

Specifically, the first outlet part of the first valve unit240is opened and the second outlet part is closed. Therefore, the first refrigerant introduced to the first valve unit240through the inlet part may be discharged to the first outlet part. Then, the flow of the first refrigerant through the first hot gas path245is limited.

The first refrigerant discharged from the first valve unit240is introduced to the first condenser211, depressurized in the first expansion device231, and introduced into the first evaporator230. The first refrigerant is evaporated in the first evaporator230and the cool air generated in this process may be supplied to the refrigerator compartment20. The first refrigerant passed through the first evaporator230may be suctioned into the first compressor201and compressed.

During the normal mode operation of the refrigerator10b, the second cycle may be operated. Specifically, the second refrigerant compressed in the second compressor202is condensed in the second condenser215and passing through the second valve unit270and the third valve unit280in order. That is, the second refrigerant introduced to the second valve unit270through the first inlet part271is discharged through the first outlet part272and introduced to the inlet part281of the third valve unit280.

The second refrigerant introduced to the third valve unit280is depressurized while passing through the second expansion device235through the first outlet part282. The refrigerant passing through the second expansion device235is introduced to the third evaporator260and evaporated, and then may be introduced to the second evaporator250and evaporated. The cool air generated in the third evaporator260is supplied to the switching chamber and the cool air generated in the second evaporator250may be supplied to the freezer compartment30. The refrigerant passing through the second evaporator250may be suctioned to the second compressor202and compressed.

When the cooling operation is not required in the third evaporator260, the refrigerant introduced to the third valve unit280is introduced to the bypass path290and may pass through the second evaporator250via the second combination part295. Therefore, the cooling operation of the switching chamber is not performed and the cooing operation of the freezer compartment30may be performed.

Second, referring toFIG.13, when the freezer compartment defrosting mode operation as the second operation mode of the refrigerator, the first valve unit240may be operated in a second operating mode. Specifically, during the freezer compartment defrosting mode operation of the refrigerator, the first refrigerant compressed in the first compressor201is introduced to the inlet part of the first valve unit240.

The first outlet part of the first valve unit240is closed and the second outlet part is opened. Therefore, the first refrigerant introduced to the first valve unit240through the inlet part may be discharged through the second outlet part. The refrigerant discharged from the first valve unit240flows in the hot gas path245and passes through the second evaporator250.

In the process of the first refrigerant of the first hot gas path245passing through the second evaporator250, the ice formed at the second evaporator250may be removed. The refrigerant passing through the second evaporator250is introduced into the first refrigerant pipe201athrough the first combination part205, and depressurized in the first expansion device231and may flow into the first evaporator230. At this time, by the closed first outlet part, the refrigerant may be restricted from flowing into the first valve unit240from the first combination part205.

The refrigerant is evaporated in the first evaporator230and cool air generated in this process may be supplied to the refrigerator compartment20. The refrigerant passing through the first evaporator230may be suctioned into the first compressor201and compressed.

Meanwhile, in the process of defrosting the second evaporator250, a circulation of the second refrigerant through the second cycle is stopped, that is, the second compressor202is not driven. The defrosting of the first evaporator230may be accomplished by using the cool air stored in the refrigerator compartment20by driving the first evaporation fan230a(natural defrosting).

Next referring toFIG.14, in a switching chamber defrosting mode operation as a third operation mode of the refrigerator, the operation of the first cycle and the second cycle of the refrigerator10bmay be made. The operation of the first cycle is the same asFIG.12, and thus detailed description will be omitted.

With respect to the operation of the second cycle, when the second compressor202is driven, the second refrigerant compressed in the second compressor202is condensed in the second condenser215and introduced into the second valve unit270. The second valve unit270may be controlled so that the first inlet part271and the second outlet part273communicate and the second inlet part274and the first outlet part272communicate.

Therefore, the second refrigerant introduced to the second valve unit270through the first inlet part271is discharged through the second outlet part273and introduced to the second hot gas path246. The second refrigerant is supplied to the third evaporator260via the second hot gas path246and performs defrosting of the third evaporator260.

The second refrigerant passing through the third evaporator260is introduced to the second valve unit270through the second inlet part274and discharged from the second valve unit270through the first outlet part272. The second refrigerant discharged from the second valve unit270is introduced to the inlet part281of the third valve unit280. The third valve unit280may be controlled so that the first outlet part282is closed and the second outlet part283is opened.

The second refrigerant introduced to the third valve unit280flows to the bypass path290through the second outlet part283. The second refrigerant flowing in the bypass path290is introduced to the second evaporator250via the second combination part295. The second refrigerant evaporated in the second evaporator250may be suctioned into the second compressor202and compressed.

According to this action, by using the high temperature refrigerant condensed in the second condenser215, the third evaporator260may be defrosted, and since the refrigerant expanded after defrosting may be evaporated in the second evaporator250, the cooling of the freezer compartment30may be made.

Referring toFIG.15a refrigerator10cmay include a first cycle including a first compressor201, a first condenser211, a first expansion device231and a first evaporator230. The refrigerator10cis provided with a second cycle including a second compressor202, a second condenser215, second and third expansion devices235and236, and second and third evaporators250and260. The second cycle of the refrigerator10cfurther includes a second valve unit370installed on an outlet side pipe of the second condenser215. For example, the second valve unit370includes a four-way valve.

The second cycle further includes a second hot gas path346extended to the third evaporator260from the second valve unit370for defrosting the third evaporator260. The second hot gas path346is connected to a bypass path390via the third evaporator260.

The bypass path390includes a third combination part397to which the second hot gas path346is connected. That is, the second hot gas path346is extended to the bypass path390from the third evaporator260and connected to the third combination part397.

The second valve unit370includes one inlet part and three outlet parts. The one inlet part includes a first inlet part connected to the outlet side pipe of the second condenser215. The three outlet parts include a first outlet part connected to an inlet side pipe of the second expansion device235, a second outlet part to which the hot gas path346is connected and a third outlet part to which the bypass path390is connected.

The refrigerant introduced into the second hot gas path346through the second outlet part is supplied to the third evaporator260and may defrost the third evaporator260. The refrigerant having passed through the third evaporator260is introduced to the bypass path390through the third combination part397and may flow to into the second evaporator250.

One side of the bypass path390is connected to the third outlet part of the second valve unit370, and the other side may be connected to a pipe connecting the second evaporator250and the third evaporator260. That is, the other side of the bypass path390may be connected to a second combination part395provided in the second refrigerant pipe202a.

First referring toFIG.16, during a normal mode operation as a first operation mode of the refrigerator10c, a first refrigerant of the first cycle circulates the first compressor201, the first condenser211, the first expansion device231and the first evaporator230and performs the cooling operation of the refrigerator compartment20.

In case of the second cycle, a second refrigerant circulates the second compressor202, the second condenser215, the second valve unit370, the third evaporator260and the second evaporator250, and performs the cooling operation of the freezer compartment30and the switching chamber. The second refrigerant introduced to the second valve unit370may be introduced to the second evaporator250via the bypass path390if the cooling operation of the switching chamber is not required. Accordingly, through the operation of the second cycle, the cooling operation of the freezer compartment30may be performed

Referring toFIG.17, when the freezer compartment defrosting mode operation as the second operation mode of the refrigerator10cis performed, the operation of the second cycle is stopped. That is, the driving of the second compressor202may be stopped.

In case of the first cycle, when the first compressor201is driven, the first refrigerant compressed in the first compressor201is introduced into the first hot gas path245through the first valve unit240. The first refrigerant is supplied to the second evaporator250and performs the defrosting operation of the second evaporator250and flows into the first expansion device231through the first combination part205. The first refrigerant depressurized in the first expansion device231is evaporated at the first evaporator230and cool air generated in the first evaporator230may be supplied to the refrigerator compartment20. According to this action, the defrosting operation of the second evaporator250and the cooling operation of the first evaporator230may be made together.

The defrosting operation of the first evaporator230may be performed in a natural defrosting method for supplying cool air stored in the refrigerator compartment20to the first evaporator230.

Referring toFIG.18, when a switching chamber defrosting mode operation as a third operation mode of the refrigerator10cis performed, the refrigerant of the first cycle circulates the first compressor201, the first condenser211, the first expansion device231and the first evaporator230and performs the cooling operation of the refrigerator compartment20.

With respect to the operation of the second cycle, the second refrigerant compressed in the second compressor202is condensed while passing the second condenser215and introduced to the second valve unit370. The second refrigerant introduced to the second valve unit370flows toward the second hot gas path346and is supplied to the third evaporator260. The second refrigerant defrosts the third evaporator260while passing through the third evaporator260and introduced to the bypass path390via the third combination part397.

The second refrigerant of the bypass path390may be introduced to the second evaporator250via the second combination part395. The refrigerant evaporated in the second evaporator250may be suctioned into the second compressor202and compressed.

Referring toFIG.19a refrigerator10dmay include a first cycle in which a first refrigerant is circulating and a second cycle in which a second refrigerant is circulating. The first cycle includes a first compressor201, a first condenser211, a first expansion device231and a first evaporator230. The second cycle includes a second compressor202, a second condenser215, second and third expansion devices235and236, and second and third evaporators250and260.

The refrigerator10dfurther includes a first valve unit240installed on an outlet side pipe of the first compressor201and a first hot gas path445connected to the first valve unit240and extended toward the second evaporator250and the third evaporator260.

One side part of the first hot gas path445is connected to the first valve unit240and the other side part is connected to a first combination part405. The first combination part405is formed at one point of a first refrigerant pipe201alocated at an outlet side of the first condenser211. Specifically, the first hot gas path445may extend from the first valve unit240to the third evaporator260to be coupled thereto, may extend from the third evaporator260to the second evaporator250, and may extend from the second evaporator250to the first combination part405.

The first hot gas path445is coupled to the second and third evaporators250and260. The second cycle further includes a second valve unit470installed on an outlet side pipe of the second condenser215and a bypass path490extended from the second valve unit470and connected to an outlet side pipe of the third evaporator260. A second combination part495to which the bypass path490is connected is provided at the outlet side pipe of the third evaporator260. The second expansion device235is located between the second valve unit470and the third evaporator260, and the third expansion device236is installed in the bypass path490.

Referring toFIG.20, during a normal mode operation as a first operation mode of the refrigerator10d, the first refrigerant of the first cycle circulates the first compressor201, the first condenser211, the first expansion device231and the first evaporator230and performs the cooling operation of the refrigerator compartment20.

In case of the second cycle, the second refrigerant circulates the second compressor202, the second condenser215, the second valve unit470, the third evaporator260and the second evaporator250, and performs the cooling operation of the freezer compartment30and the switching chamber The second refrigerant introduced into the second valve unit470may be introduced to the second evaporator250via the bypass path490if the cooling operation of the switching chamber is not required. Therefore, the cooling operation of the freezer compartment30may be performed through the operation of the second cycle.

Referring toFIG.21, when the defrosting mode operation of the freezer compartment and the switching chamber as a second operation mode of the refrigerator10dis performed, the operation of the second cycle is stopped. That is, the driving of the second compressor202may be stopped.

In case of the first cycle, when the first compressor201is driven, the first refrigerant compressed in the first compressor201is introduced to the first hot gas path445through the first valve unit240. The first refrigerant is first supplied to the third evaporator260and then performs defrosting of the third evaporator260while flowing in the first hot gas path445.

The first refrigerant having passed through the third evaporator260is supplied to the second evaporator250and performs defrosting of the second evaporator250. The first refrigerant having passed through the second evaporator250passes through the first expansion device231via the first combination part405.

The first refrigerant depressurized in the first expansion device231is evaporated in the first evaporator230and the cool air generated in the first evaporator230is supplied to the refrigerator compartment20. The refrigerant evaporated in the first evaporator230may be suctioned to the first compressor201and compressed. According to this action, in the process in which the cooling operation of the refrigerator compartment20is performed, since the defrosting operation of the second and third evaporators250and260may be performed together, the cooling performance and the defrosting performance may be improved.

Meanwhile, since the evaporation temperature of the first evaporator230is relatively high, the cool air of the refrigerator compartment20may be supplied to the first evaporator230by driving the first evaporation fan230a. In this process, the defrosting of the first evaporator230may be performed (natural defrosting operation).

The defrosting of the evaporator can be performed using the high temperature refrigerant (or the hot gas), and may not require the installation of a conventional defrosting heater thereby reducing operation costs.

The refrigerant of the first cycle passed through the compressor or the condenser may flow to the evaporator of the second cycle, perform the defrosting operation, be condensed while the defrosting operation is performed, and then can be evaporated in the evaporator of the first cycle, and thus the storage compartment in which the evaporator of the first cycle is installed can be cooled.

The condensation temperature of the refrigerant may be lowered during the flowing of the refrigerant in the evaporator of the second cycle, and also cooling efficiency in the evaporator of the first cycle can be improved by evaporating in the evaporator of the first cycle after condensation.

The evaporator may include the first pipe through which the refrigerant to be evaporated flows, the second pipe through which the high temperature refrigerant flows, and the fin which is coupled to the first and second pipes, and thus in the defrosting operation, the ice formed on the evaporator can be removed using the high temperature refrigerant, and thus defrosting efficiency can be improved.

The heat of the high temperature refrigerant may be transferred to the evaporator in a heat conduction method, and the defrosting efficiency may be improved, the defrosting time may be shortened, and a temperature of the storage compartment may be prevented from being excessively increased during the defrosting operation.