REFRIGERATOR HAVING A EXPANSION UNIT TO EXECUTE CONDENSING FUNCTION Technical Field The present invention relates to a refrigerator, and more particularly, the present invention relates to a refrigerator having an expansion unit to execute a condensing function, in which gaseous refrigerant generated in an evaporator is adiabatically expanded and thereby condensed in the expansion unit, so that a condenser can be remarkably decreased in its size or even eliminated.

Background Art As shown in FIG. 4, a conventional refrigerator comprises a motor 100, a compressor 200 driven by the motor 100, a condenser 300, an expansion valve 400, and an evaporator 500. The conventional refrigerator further comprises first through fourth connection lines 250, 350, 450 and 550 for operationally connecting the compressor 200, condenser 300, expansion valve 400 and evaporator 500 one with another.

Hereafter, operation of the conventional refrigerator constructed as mentioned above will be described.

First, gaseous refrigerant is compressed to a high pressure by the compressor 200 driven by the motor 100, and

then delivered to the condenser 300 through the first connection line 250. The high pressure refrigerant compressed in the compressor 200 is cooled in the condenser 300 by air or water to be converted into a liquid phase.

The refrigerant condensed in the condenser 300 is delivered to the expansion valve 400 through the second connection line 350. The expansion valve 400 reduces a pressure of the refrigerant to allow the liquid refrigerant to be evaporated in the evaporator 500.

The low pressure refrigerant passed through the expansion valve 400 is delivered to the evaporator 500 through the third connection line 450. In the evaporator 500, the refrigerant absorbs heat and is vaporized while cooling air which flows through the evaporator 500. The vaporized refrigerant is delivered to the compressor 200 through the fourth connection line 550 to complete a refrigerating cycle.

However, the conventional refrigerator suffers from defects in that, while the condenser 300 is used to condense and liquefy the refrigerant compressed in the compressor 200, since the condenser 300 is installed on a rear surface or a bottom surface of the refrigerator such as a fridge, an air conditioner, and the like, or is separately installed outdoors, inconvenience is caused upon moving or installing the refrigerator.

Also, while it is the norm that the condenser 300

comprises a heat exchanger which is formed by bending an elongate tube a multitude of times to obtain a wide heat transfer area and thereby improve a heat transfer efficiency, a pressure loss occurs while the refrigerant flows through the tube which defines a flow path of a substantial length.

Hence, in order to compensate for this pressure loss, an increased amount of electrical energy should be applied to the compressor 200.

Further, in the case that a separate cooling fan or cooling water circulation device is employed to improve a heat transfer efficiency of the condenser 300, energy consumption is increased due to the operation of the cooling fan or cooling water circulation device.

Moreover, under hot summer weather conditions, discomfort can be caused by heat emitted from the condenser 300 separately installed outdoors.

Disclosure of the Invention Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a refrigerator in which gaseous refrigerant generated in an evaporator is adiabatically expanded and thereby condensed in an expansion unit, so that a condenser can be remarkably decreased in its size or even eliminated, whereby it is

possible to save a manufacturing cost due to installation of the condenser, and avoid inconvenience caused upon installing the condenser and moving the refrigerator.

Another object of the present invention is to provide a refrigerator which can decrease a pressure loss occurring while the refrigerant flows through a condenser comprising a heat exchanger defining a flow path of a substantial length.

Another object of the present invention is to provide a refrigerator which is constructed to allow a cooling fan or a cooling water circulation device employed for improving a heat transfer efficiency to be decreased in its size or even eliminated, thereby decreasing a manufacturing cost and power consumption of the refrigerator.

Still another object of the present invention is to provide a refrigerator which can significantly reduce an amount of heat emitted from a condenser, whereby discomfort caused under hot summer weather conditions by heat emitted from the condenser separately installed outdoors can be avoided.

Yet still another object of the present invention is to provide a refrigerator wherein, since it is possible to drive a compressor using power produced while refrigerant is adiabatically expanded in an expansion unit, an amount of electrical energy supplied to the refrigerator can be markedly decreased, and surplus energy can be used for other purposes

such as illumination of a chilling chamber, driving of a cooling air circulation fan, etc.

In order to achieve the above objects, according to the present invention, there is provided a refrigerator using an expansion unit for executing a condensing function, comprising : a compressor having connected to a shaft thereof the expansion unit and a combined motor and generator ; a first connection pipe connected between the compressor and a humidity adjuster to deliver compressed gaseous refrigerant to the humidity adjuster ; a second connection pipe connected between the humidity adjuster and the expansion unit to deliver humidity-adjusted humidified gaseous refrigerant to the expansion unit ; a third connection pipe connected between the expansion unit and a condenser to deliver refrigerant having an uncondensed gaseous refrigerant part and a condensed liquid refrigerant part to the condenser and then to condense the uncondensed gaseous refrigerant part ; a fourth connection pipe connected between the condenser and a circulation pump to deliver liquefied refrigerant to the circulation pump ; a fifth connection pipe connected between the circulation pump and a refrigerant amount adjuster to deliver pumped liquid refrigerant to the refrigerant amount adjuster ; a sixth connection pipe connected between one outlet of the refrigerant amount adjuster and the humidity adjuster to deliver a portion of the pumped liquid refrigerant to the

humidity adjuster ; a seventh connection pipe connected between the other outlet of the refrigerant amount adjuster and an evaporator ; and an eighth connection pipe connected between the evaporator and the compressor to deliver vaporized refrigerant to the compressor.

Brief Description of the Drawings The above objects, and other features and advantages of the present invention will become more apparent after a reading of the following detailed description when taken in conjunction with the drawings, in which : FIG. 1 is a systematic view illustrating a refrigerator in accordance with a first embodiment of the present invention ; FIG. 2 is a systematic view illustrating a refrigerator in accordance with a second embodiment of the present invention ; FIG. 3 is a systematic view illustrating a refrigerator in accordance with a third embodiment of the present invention ; and FIG. 4 is a systematic view illustrating a conventional refrigerator.

Best Mode for Carrying Out the Invention Reference will now be made in greater detail to a

preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts.

FIG. 1 is a systematic view illustrating a refrigerator using an expansion unit for executing a condensing function in accordance with a first embodiment of the present invention.

A construction of the refrigerator according to the first embodiment of the present invention will be described below.

The refrigerator includes a compressor 1. An expansion unit 2 and a combined motor and generator 5 are connected to the compressor 1 via connection shafts. A first connection pipe 11 is connected between the compressor 1 and a humidity adjuster 10 to deliver gaseous refrigerant compressed in the compressor 1 to the humidity adjuster 10. The humidity adjuster 10 has nozzles 33 for injecting liquid refrigerant.

A second connection pipe 12 is connected between the humidity adjuster 10 and the expansion unit 2 to deliver humidified gaseous refrigerant humidity-adjusted in the humidity adjuster 10 to the expansion unit 2. A third connection pipe 13 is connected between the expansion unit 2 and a condenser 3 to deliver refrigerant having a gaseous refrigerant part uncondensed in the expansion unit 2 and a liquid refrigerant part condensed in the expansion unit 2 to the condenser 3 and

then to condense the uncondensed gaseous refrigerant part. A fourth connection pipe 14 is connected between the condenser 3 and a circulation pump 20 to deliver refrigerant liquefied in the condenser 3 to the circulation pump 20. A fifth connection pipe 15 is connected between the circulation pump 20 and a refrigerant amount adjuster 30 to deliver liquid refrigerant pumped by the circulation pump 20 to the refrigerant amount adjuster 30. A sixth connection pipe 16 is connected between one outlet of the refrigerant amount adjuster 30 and the humidity adjuster 10 to deliver a portion of the pumped liquid refrigerant to the humidity adjuster 10.

A seventh connection pipe 17 is connected between the other outlet of the refrigerant amount adjuster 30 and an evaporator 4. An eighth connection pipe 18 is connected between the evaporator 4 and the compressor 1 to deliver refrigerant vaporized in the evaporator 4 to the compressor 1.

A refrigerating method by the refrigerator according to the first embodiment of the present invention, constructed as mentioned above, will be described below.

In a gaseous refrigerant compressing step, gaseous refrigerant generated in the evaporator 4 is sucked into the compressor 1 and compressed to a high pressure, while the compressor 1 is driven by the combined motor and generator 5.

In a humidified gaseous refrigerant generating step, liquid refrigerant delivered from the refrigerant amount adjuster 30

is injected, through the nozzles 33 in the humidity adjuster 10, to high pressure gaseous refrigerant supplied from the compressor 1, and thereby, humidified gaseous refrigerant is generated. In an expanding and condensing step, the humidified gaseous refrigerant generated in the humidity adjuster 10 is adiabatically expanded in the expansion unit 2 to produce shaft power, and thereby a portion of the humidified gaseous refrigerant is condensed. In a refrigerant condensing step, refrigerant, which is supplied from the expansion unit 2 and has an uncondensed gaseous refrigerant part and a condensed liquid refrigerant part, is condensed in the condenser 3. In a liquid refrigerant supply adjusting step, the portion of liquid refrigerant condensed by the condenser 3 and delivered to the refrigerant amount adjuster 30 through the circulation pump 20 is supplied to the humidity adjuster 10, and a remaining portion of the liquid refrigerant is supplied to the evaporator 4. In a liquid refrigerant evaporating step, the liquid refrigerant is vaporized in the evaporator 4 by absorbing external heat, and vaporized refrigerant is supplied to the compressor 1.

Hereafter, operation of the refrigerator according to the first embodiment of the present invention will be described in detail with reference to FIG. 1.

Initially, if power is applied to the combined motor and generator 5 to drive the compressor 1, the compressor 1 sucks

gaseous refrigerant supplied from the evaporator 4 through the eighth connection pipe 18 and then compresses the gaseous refrigerant to a high pressure. The refrigerant compressed to the high pressure in this way is delivered to the humidity adjuster 10 through the first connection pipe 11.

The humidity adjuster 10 injects through the nozzles 33 liquid refrigerant generated in the condenser 3 and supplied thereto through the circulation pump 20 and the refrigerant amount adjuster 30 to the high pressure gaseous refrigerant supplied from the compressor 1. Thus, humidified gaseous refrigerant having a desired humidity is generated in a manner such that the gaseous refrigerant can be easily condensed while being adiabatically expanded in the expansion unit 2.

The expansion unit 2 adiabatically expands the humidified gaseous refrigerant supplied thereto through the second connection pipe 12 to produce shaft power capable of rotating the compressor 1, etc. At this time, as the humidified gaseous refrigerant flowing into the expansion unit 2 is diminished in its internal energy, it is decreased in its temperature and pressure, and thereby, a portion of the humidified gaseous refrigerant is condensed.

The condenser 3 condenses and liquefies the mixed refrigerant which is supplied from the expansion unit 2 through the third connection pipe 13 and has the uncondensed gaseous refrigerant part and the condensed liquid refrigerant

part. Thereafter, the condenser 3 delivers liquefied refrigerant to the refrigerant amount adjuster 30 through the fourth connection pipe 14, the circulation pump 20 and the fifth connection pipe 15.

The refrigerant amount adjuster 30 supplies the portion of the liquid refrigerant through the sixth connection pipe 16 to the humidity adjuster 10, and at the same time, the remaining portion of the liquid refrigerant through the seventh connection pipe 17 to the evaporator 4. The liquid refrigerant which is supplied to the evaporator 4 is vaporized by absorbing external heat, and the vaporized refrigerant is supplied to the compressor 1 through the eighth connection pipe 18.

In particular, if operation of the refrigerator is performed in a steady state, it is possible to drive the compressor 1 or augment electrical driving force for the compressor 1, using shaft power produced while the humidified gaseous refrigerant is adiabatically expanded in the expansion unit 2. Also, by driving the combined motor and generator 5 using surplus energy which remains after driving the compressor 1, it is possible to produce electric power which can be used for other purposes such as illumination of a chilling chamber, driving of a cooling air circulation fan, etc, whereby an amount of electrical energy required for operation of the refrigerator can be significantly reduced.

FIG. 2 is a systematic view illustrating a refrigerator using an expansion unit for executing a condensing function in accordance with a second embodiment of the present invention.

A construction of the refrigerator according to the second embodiment of the present invention will be described below.

The refrigerator includes a compressor 1. An expansion unit 2 and a combined motor and generator 5 are connected to the compressor 1. A first connection pipe 11 is connected between the compressor 1 and a humidity adjuster 10 to deliver gaseous refrigerant compressed in the compressor 1 to the humidity adjuster 10. The humidity adjuster 10 has nozzles 33 for injecting liquid refrigerant. A second connection pipe 12 is connected between the humidity adjuster 10 and the expansion unit 2 to deliver humidified gaseous refrigerant humidity-adjusted in the humidity adjuster 10 to the expansion unit 2. An outlet of the expansion unit 2 is connected through a third connection pipe 13 to a vapor-liquid separator 6. A fourth connection pipe 14 is connected between a lower end of the vapor-liquid separator 6 and a circulation pump 20 to deliver liquid refrigerant separated in the vapor-liquid separator 6 to the circulation pump 20. A fifth connection pipe 15 is connected between the circulation pump 20 and a refrigerant amount adjuster 30 to deliver liquid refrigerant pumped by the circulation pump 20 to the refrigerant amount adjuster 30. A sixth connection pipe 16 is connected between

one outlet of the refrigerant amount adjuster 30 and the humidity adjuster 10 to deliver a portion of the pumped liquid refrigerant to the humidity adjuster 10. A seventh connection pipe 17 is connected between the other outlet of the refrigerant amount adjuster 30 and an evaporator 4. An eighth connection pipe 18 is connected between the evaporator 4 and the compressor 1 to deliver refrigerant vaporized in the evaporator 4 to the compressor 1. A ninth connection pipe 19 is connected between an upper end of the vapor-liquid separator 6 and the compressor 1 to deliver gaseous refrigerant separated in the vapor-liquid separator 6 to the compressor 1.

A refrigerating method by the refrigerator according to the second embodiment of the present invention, constructed as mentioned above, will be described below.

In a gaseous refrigerant compressing step, gaseous refrigerant generated in the evaporator 4 and gaseous refrigerant separated in the vapor-liquid separator 6 are sucked into the compressor 1 and compressed to a high pressure, while the compressor 1 is driven by the combined motor and generator 5. In a humidified gaseous refrigerant generating step, liquid refrigerant delivered from the refrigerant amount adjuster 30 is injected, through the nozzles 33 in the humidity adjuster 10, to high pressure gaseous refrigerant supplied from the compressor 1, and

thereby, humidified gaseous refrigerant is generated. In an expanding and condensing step, the humidified gaseous refrigerant generated in the humidity adjuster 10 is adiabatically expanded in the expansion unit 2 to produce shaft power, and thereby a portion of the humidified gaseous refrigerant is condensed. In a vapor-liquid separating step, mixed refrigerant supplied from the expansion unit 2 is separated, in the vapor-liquid separator 6, into gaseous refrigerant and liquid refrigerant. In a liquid refrigerant supply adjusting step, the portion of liquid refrigerant separated in the vapor-liquid separator 6 and delivered to the refrigerant amount adjuster 30 through the circulation pump 20 is supplied to the humidity adjuster 10, and a remaining portion of the liquid refrigerant is supplied to the evaporator 4. In a liquid refrigerant evaporating step, the liquid refrigerant is vaporized in the evaporator 4 by absorbing external heat, and vaporized refrigerant is supplied to the compressor 1.

Hereafter, operation of the refrigerator according to the second embodiment of the present invention will be described in detail with reference to FIG. 2.

Initially, if power is applied to the combined motor and generator 5 to drive the compressor 1, the compressor 1 sucks gaseous refrigerant supplied from the evaporator 4 through the eighth connection pipe 18 and gaseous refrigerant separated in

the vapor-liquid separator 6 and supplied through the ninth connection pipe 19, and then compresses the gaseous refrigerant to a high pressure.

The humidity adjuster 10 injects through the nozzles 33 liquid refrigerant supplied from the refrigerant amount adjuster 30 to the high pressure gaseous refrigerant supplied from the compressor 1. Thus, humidified gaseous refrigerant having a desired humidity is generated in a manner such that the gaseous refrigerant can be easily condensed while being adiabatically expanded in the expansion unit 2.

The expansion unit 2 adiabatically expands the humidified gaseous refrigerant supplied thereto through the second connection pipe 12 to produce shaft power capable of rotating the compressor 1, etc. At this time, as the humidified gaseous refrigerant flowing into the expansion unit 2 is diminished in its internal energy, it is decreased in its temperature and pressure, and thereby, a portion of the humidified gaseous refrigerant is condensed.

The vapor-liquid separator 6 separates the mixed refrigerant supplied from the expansion unit 2 through the third connection pipe 13, into gaseous refrigerant and liquid refrigerant. Thereafter, the vapor-liquid separator 6 delivers gaseous refrigerant to the compressor 1 through the ninth connection pipe 19, and at the same time, liquid refrigerant to the refrigerant amount adjuster 30 through the

fourth connection pipe 14, the circulation pump 20 and the fifth connection pipe 15.

The refrigerant amount adjuster 30 delivers the portion of the liquid refrigerant through the sixth connection pipe 16 to the humidity adjuster 10, and at the same time, supplies the remaining portion of the liquid refrigerant through the seventh connection pipe 17 to the evaporator 4. The liquid refrigerant which is supplied to the evaporator 4 is vaporized by absorbing external heat, and the vaporized refrigerant is supplied to the compressor 1 through the eighth connection pipe 18.

If operation of the refrigerator is performed in a steady state, since it is possible to use shaft power produced upon adiabatically expanding the humidified gaseous refrigerant in the expansion unit 2 as power for driving the refrigerator, an amount of electrical energy required for operation of the refrigerator can be significantly reduced.

In particular, in this second embodiment of the present invention, because a condenser is not used, it is impossible to condense all of the refrigerant discharged from the expansion unit 2. Since the gaseous refrigerant, which is not condensed in the expansion unit 2, is recirculated from the vapor-liquid separator 6 through the ninth connection pipe 19 to the compressor 1, an amount of liquid refrigerant supplied to the evaporator 4 and the humidity adjuster 10 is reduced.

However, various inconvenience caused upon installation and utilization of a condenser can be removed, and all of a condenser installation cost can be saved.

FIG. 3 is a systematic view illustrating a refrigerator using an expansion unit for executing a condensing function in accordance with a third embodiment of the present invention.

A construction of the refrigerator according to the third embodiment of the present invention will be described below.

The refrigerator includes a compressor 1. An expansion unit 2 and a combined motor and generator 5 are connected to the compressor 1. A first connection pipe 11 is connected between the compressor 1 and a humidity adjuster 10 to deliver gaseous refrigerant compressed in the compressor 1 to the humidity adjuster 10. The humidity adjuster 10 has nozzles 33 for injecting liquid refrigerant. A second connection pipe 12 is connected between the humidity adjuster 10 and the expansion unit 2 to deliver humidified gaseous refrigerant humidity-adjusted in the humidity adjuster 10 to the expansion unit 2. A third connection pipe 13 is connected between the expansion unit 2 and a vapor-liquid separator 6 to deliver mixed refrigerant having a gaseous refrigerant part uncondensed in the expansion unit 2 and a liquid refrigerant part condensed in the expansion unit 2, to the vapor-liquid separator 6. A fourth connection pipe 14 is connected to the vapor-liquid separator 6 to deliver liquid refrigerant to a

circulation pump 20. A fifth connection pipe 15 is connected between the circulation pump 20 and a refrigerant amount adjuster 30'to deliver liquid refrigerant pumped by the circulation pump 20 to the refrigerant amount adjuster 30. A sixth connection pipe 16 is connected between one outlet of the refrigerant amount adjuster 30 and the humidity adjuster 10 to deliver a portion of the pumped liquid refrigerant to the humidity adjuster 10. A seventh connection pipe 17 is connected between the other outlet of the refrigerant amount adjuster 30 and an evaporator 4. An eighth connection pipe 21 is connected between the evaporator 4 and the first connection pipe 11 to allow gaseous refrigerant vaporized in the evaporator 4 to be mixed with gaseous refrigerant of the compressor 1 and then pass through the humidity adjuster 10.

A ninth connection pipe 19 is connected to the vapor-liquid separator 6 to deliver gaseous refrigerant to the compressor 1.

A refrigerating method by the refrigerator according to the third embodiment of the present invention, constructed as mentioned above, will be described below.

In a gaseous refrigerant compressing step, gaseous refrigerant separated in the vapor-liquid separator 6 is sucked into the compressor 1 and compressed to a high pressure, while the compressor 1 is driven by the combined motor and generator 5. In a humidified gaseous refrigerant

generating step, liquid refrigerant separated in the vapor- liquid separator 6 is injected, through the nozzles 33 in the humidity adjuster 10, to gaseous refrigerant supplied from the compressor 1 and gaseous refrigerant generated in the evaporator 4, and thereby humidified gaseous refrigerant is generated. In an expanding and condensing step, the humidified gaseous refrigerant generated in the humidity adjuster 10 is adiabatically expanded in the expansion unit 2 to produce shaft power, and thereby a portion of the humidified gaseous refrigerant is condensed. In a vapor- liquid separating step, mixed refrigerant supplied from the expansion unit 2 is separated, in the vapor-liquid separator 6, into gaseous refrigerant and liquid refrigerant. In a liquid refrigerant supply adjusting step, the portion of liquid refrigerant separated in the vapor-liquid separator 6 and delivered to the refrigerant amount adjuster 30 through the circulation pump 20 is supplied to the humidity adjuster 10, and a remaining portion of the liquid refrigerant is supplied to the evaporator 4. In a liquid refrigerant evaporating step, the liquid refrigerant having a low boiling point is vaporized in the evaporator 4 by absorbing external heat.

Hereafter, operation of the refrigerator according to the third embodiment of the present invention will be described in detail with reference to FIG. 3.

Initially, if power is applied to the combined motor and generator 5 to drive the compressor 1, the compressor 1 sucks gaseous refrigerant separated in the vapor-liquid separator 6 and supplied through the ninth connection pipe 19, and then compresses the gaseous refrigerant to a high pressure.

The humidity adjuster 10 injects through the nozzles 33 liquid refrigerant delivered from the refrigerant amount adjuster 30 to the high pressure gaseous refrigerant supplied from the compressor 1 through the first connection pipe 11 and the high pressure gaseous refrigerant which is under an overheated status and is generated in the evaporator 4 and supplied through the eight connection pipe 21. Thus, humidified gaseous refrigerant having a desired humidity is generated in a manner such that the gaseous refrigerant can be easily condensed while being adiabatically expanded in the expansion unit 2.

The expansion unit 2 adiabatically expands the humidified gaseous refrigerant supplied thereto through the second connection pipe 12 to produce shaft power capable of rotating the compressor 1, etc. At this time, as the humidified gaseous refrigerant flowing into the expansion unit 2 is diminished in its internal energy, it is decreased in its temperature and pressure, and thereby, a portion of the humidified gaseous refrigerant is condensed.

The vapor-liquid separator 6 separates the mixed

refrigerant supplied from the expansion unit 2 through the third connection pipe 13, into gaseous refrigerant and liquid refrigerant. Thereafter, the vapor-liquid separator 6 delivers gaseous refrigerant to the compressor 1 through the ninth connection pipe 19, and at the same time, liquid refrigerant to the refrigerant amount adjuster 30 through the fourth connection pipe 14, the circulation pump 20 and the fifth connection pipe 15.

The refrigerant amount adjuster 30 delivers the portion of the liquid refrigerant through the sixth connection pipe 16 to the humidity adjuster 10, and at the same time, supplies the remaining portion of the liquid refrigerant through the seventh connection pipe 17 to the evaporator 4. The liquid refrigerant which is supplied to the evaporator 4 is vaporized by absorbing external heat, and the vaporized refrigerant is supplied to the humidity adjuster 10 through the eighth connection pipe 21 connected to the first connection pipe 11.

In particular, in this third embodiment of the present invention, because refrigerant having a low boiling point is used, a degree of superheating of the refrigerant vaporized in the evaporator 4 is raised and therefore, a pressure is increased. As a consequence, since the gaseous refrigerant vaporized in the evaporator 4 is not compressed in the compressor 1 and instead is supplied to the vapor-liquid separator 6 to be directly delivered to the humidity adjuster

10 along with high pressure gaseous refrigerant compressed in the compressor 1, a compression load can be lessened.

If operation of the refrigerator is performed in a steady state, since it is possible to use shaft power produced upon adiabatically expanding the humidified gaseous refrigerant in the expansion unit 2 as power for driving the refrigerator, an amount of electrical energy required for operation of the refrigerator can be significantly reduced.

Also, in this second embodiment of the present invention, because a condenser is not used, it is impossible to condense all of the refrigerant discharged from the expansion unit 2. Since the gaseous refrigerant, which is not condensed in the expansion unit 2, is recirculated from the vapor-liquid separator 6 through the ninth connection pipe 19 to the compressor 1, an amount of liquid refrigerant supplied to the evaporator 4 and the humidity adjuster 10 is reduced.

However, various inconvenience caused upon installation and utilization of a condenser can be removed, and all of a condenser installation cost can be saved.

Industrial Applicability As apparent from the above description, the refrigerant according to the present invention provides advantages in that, since a humidity of gaseous refrigerant generated in an evaporator is adjusted and in this humidity-adjusted state,

the gaseous refrigerant is adiabatically expanded and thereby condensed in an expansion unit, a condenser can be remarkably decreased in its size or even eliminated, whereby it is possible to save a manufacturing cost due to installation of the condenser, and avoid inconvenience caused upon separately installing the condenser outdoors.

Also, in the present invention, because the condenser can be remarkably decreased in its size or even eliminated, a pressure loss occurring while the refrigerant flows through the condenser comprising a heat exchanger defining a flow path of a substantial length can be decreased, whereby energy required for driving the refrigerator can be reduced.

Further, in the present invention, because the condenser can be remarkably decreased in its size or even eliminated, a cooling fan or a cooling water circulation device employed for improving a heat transfer efficiency can also be decreased in its size or even eliminated, whereby a cost incurred upon manufacturing and installing the refrigerator and power needed for driving the refrigerator can be decreased.

Moreover, in the present invention, due to the fact that it is possible to significantly reduce cm amount of heat emitted from the condenser, unpleasantness caused under hot summer weather conditions by heat emitted from the condenser separately installed outdoors can be avoided.

Furthermore, in the present invention, as the

refrigerant having a low boiling point is used, a degree of superheating of the refrigerant vaporized in the evaporator is raised and therefore, its pressure is increased. As a consequence, since the gaseous refrigerant vaporized in the evaporator is not compressed in a compressor and instead is delivered to a vapor-liquid separator to be directly supplied to a humidity adjuster along with high pressure gaseous refrigerant compressed in the compressor, a compression load can be lessened.

In addition, in the present invention, by the fact that it is possible to drive the compressor using power produced while the refrigerant is adiabatically expanded in the expansion unit, an amount of electrical energy required for driving the refrigerator can be markedly decreased, and surplus energy can be used for other purposes such as illumination of a chilling chamber, driving of a cooling air circulation fan, etc.