JP2002277073A - Refrigerating equipment and refrigerating equipment for overland transportation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide inexpensive refrigerating equipment and refrigerating equipment for overland transportation. SOLUTION: The refrigerating equipment has an evaporator 7 for evaporating a liquid-phase refrigerant supplied thereto and for cooling a substance to be cooled, a compressor 15, compressing the refrigerant gasified by the evaporator 7, a condenser 10 condensing and liquefying the refrigerant compressed by the compressor 15, an expansion means 9 for expanding the liquefied refrigerant, and a gas-liquid heat exchange means for making the gas refrigerant and the liquid refrigerant exchange heat between them. The gas-liquid heat exchange means is equipped with low-pressure refrigerant piping 5 connecting the evaporator 7 and the compressor 15 and making the gas refrigerant flow through, and high-pressure refrigerant piping 6 connecting the condenser 10 and the expansion means 9 and making the liquid refrigerant flow through. One of the above refrigerant piping is wound helically on the outer peripheral surface of the other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a refrigeration apparatus,
In particular, the present invention relates to a refrigeration apparatus suitable for being mounted on a land transportation vehicle.

[0002]

2. Description of the Related Art A general refrigeration system includes devices such as an evaporator, a compressor, and a condenser, and a refrigeration cycle is formed by circulating a refrigerant between the devices. A land transportation refrigeration apparatus, which is an example of the refrigeration apparatus, is mounted on a land transportation vehicle such as a truck, and cools the inside of a container (cooler) provided in the land transportation vehicle (hereinafter, referred to as a “refrigerated vehicle”). It is a device for performing. With the refrigeration unit for land transportation (hereinafter referred to as a "refrigeration unit"), the luggage loaded in the refrigerator compartment of the refrigerator car is transported while being kept at a low temperature.

FIG. 4 shows an example of a conventional refrigeration system. The present apparatus is mounted on a refrigerator car 1 having a cool box 2, and includes an evaporator unit 3 installed at an upper end inside the cool box 2 and a condensing unit 4 installed at a lower outside of the cool box 2. Is the main component. In addition, the evaporator unit 3 and the condensing unit 4
They are connected by a low-pressure refrigerant pipe 105 and a high-pressure refrigerant pipe 106.

[0004] As shown in FIG. 5, the evaporator unit 3
Includes an evaporator 7, an evaporator fan 8, a gas-liquid heat exchanger 107, and an expansion valve 9. On the other hand, the condensing unit 4 includes a condenser 10, a condenser fan 11, a receiver 12, a dryer 13,
An accumulator 14 and a compressor 15 are provided.

In FIG. 5, when the compressor 15 of the condensing unit 4 is driven by the power of an engine or the like (not shown), the high-pressure / high-temperature gas refrigerant compressed by the compressor 15 is sent to the condenser 10, where Outside air 50 introduced by the condenser fan 11 at
And is condensed and liquefied. The liquid refrigerant passes through a receiver 12 and a dryer 13 and is sent to a gas-liquid heat exchanger 107 provided in the evaporator unit 3 by a high-pressure refrigerant pipe 106 connecting the condensing unit 4 and the evaporator unit 3, where The liquid refrigerant is a low-pressure / low-temperature gas refrigerant sent from the evaporator 7,
The liquid refrigerants exchange heat, and the liquid refrigerant is further subcooled. The supercooled liquid refrigerant that has exited the gas-liquid heat exchanger 107 expands at the expansion valve 9, enters the evaporator 7, and flows through the pipes inside the evaporator 7, and is sent by the evaporator 7 to the cold storage 2. It exchanges heat with the circulating air inside, and this air is cooled and is blown into the cool box 2 as cooling air 60 by the evaporator fan 8. The refrigerant that has exchanged heat with the circulating air in the cool box 2 in the evaporator 7 evaporates and is sent to the gas-liquid heat exchanger 107, where it is heated by exchanging heat with the liquid refrigerant as described above, and the degree of superheat is reduced. The increased superheated gas refrigerant is sent to the accumulator 14 through the low-pressure refrigerant pipe 105 connecting the evaporator unit 3 and the condensing unit 4, and returns to the compressor 15 from here.

FIG. 7 shows a refrigerating cycle of the refrigerating apparatus on a refrigerant Mollier chart. In the figure, the horizontal axis represents enthalpy, and the vertical axis represents pressure. The cycle of ABCD shown by a solid line in the figure shows the cycle A'-B'-C'- shown by a dotted line when the gas-liquid heat exchanger 107 is not provided.
The cycle of D 'is a case where the gas-liquid heat exchanger 107 is provided. In FIG. 7, C and C ′ are refrigerant states at the inlet of the expansion valve 9, and the degree of supercooling of the liquid refrigerant is increased by the gas-liquid heat exchanger 107 (shown in the range of C to C ′). Indicates that
This indicates that the evaporator 8 can increase the refrigerating capacity corresponding to the increase in the enthalpy indicated by the range from D to D '. On the other hand, A and A '
Shows the refrigerant state at the inlet of the gas-liquid heat exchanger 107,
The gas refrigerant at the inlet of the compressor 15 is heated,
There is an increase in the degree of superheat of the suction gas of the compressor 15 shown in the range of A ', and as a result, the temperature of the discharge gas of the compressor 15 is accompanied by a rise in the temperature shown in the range of B to B'.

As described above, the gas-liquid heat exchanger 107 is generally used as a means for improving the refrigerating capacity of the refrigerating apparatus, and is usually disposed in the evaporator unit 3 as shown in FIG. I have.

Here, the detailed structure of the gas-liquid heat exchanger 107 is shown in FIG. The gas-liquid heat exchanger 107 includes a shell 108 through which a gas refrigerant flows, and a fin tube 109 disposed inside the shell 108 and through which a liquid refrigerant flows. The shell 108 has a substantially capsule shape, and at one end thereof, a gas refrigerant inflow portion 110 into which gas refrigerant from the evaporator 7 flows, and at the other end, a gas refrigerant outflow portion 111 through which gas refrigerant flows out to the accumulator 14.
And The fin tube 109 extends from the vicinity of the gas refrigerant inlet 110 inside the shell 108 to the gas refrigerant outlet 11.
1 and spirally disposed around the gas refrigerant outlet 11
A liquid refrigerant inflow portion 112 into which the liquid refrigerant from the dryer 13 flows in at one end, and a liquid refrigerant outflow portion through which the liquid refrigerant flows out to the expansion valve 9 at the gas refrigerant inflow portion 110 side end. 11
3 Further, the fin tube 109 has a large number of substantially donut-shaped thin plates (fins) 114 attached to the outer peripheral surface thereof. Although not shown in FIG. 6, the fin 114 is also attached to the entire spiral portion.

According to the gas-liquid heat exchanger 107 having the above structure, the gas refrigerant flows inside the shell 108, while the liquid refrigerant flows inside the fin tube 109 in the opposite direction to the flow of the gas refrigerant. Heat exchange is performed between the refrigerant and the gas refrigerant. As a result, the liquid refrigerant is supercooled, and the gas refrigerant has an increased degree of superheat.

By the way, in order to sufficiently exchange heat between the liquid refrigerant and the gas refrigerant, it is necessary to provide a long time and a long distance between them. Here, since the fin tube 109 is formed in a spiral shape, it is possible to make the contact time and distance between them both longer than in the case of being formed linearly. The fin 1 is provided on the outer peripheral surface of the fin tube 109.
Since the fins 14 are attached, the heat transfer area can be greatly increased as compared with the case where the fins 114 are not attached. With these, the gas-liquid heat exchanger 10
7 can efficiently perform heat exchange despite its small size, and as a result, the gas-liquid heat exchanger 107 can be disposed inside the evaporator unit 3. I have.

[0011]

However, the refrigeration system provided with the gas-liquid heat exchanger 107 has had to be expensive. The main cause is that it takes time and effort to manufacture the gas-liquid heat exchanger 107. That is, the gas-liquid heat exchanger 107 has a structure in which the fin tube 109 is provided inside the hollow shell 108. For this reason,
A fin tube 109 is provided inside the divided shell 108.
After arranging, the end plates at both ends of the shell 108 need to be joined by welding. Here, the gas refrigerant is the shell 1
08, the shell 108 is required to have high airtightness. Further, the fin tube 109 has a complicated structure in which a large number of fins 114 are attached to the outer peripheral surface of the tube, and further, such a tube needs to be spirally wound at a short pitch in a substantially spring-like manner. In particular, the processing is troublesome. For the reasons described above, the refrigeration system including the gas-liquid heat exchanger 107 has to be expensive.

An object of the present invention is to provide an inexpensive refrigeration system in view of the above problems.

[0013]

According to the present invention, there is provided a refrigerating apparatus comprising: an evaporator for supplying a liquid-phase refrigerant to evaporate the refrigerant and cooling an object to be cooled; and the refrigerant gasified by the evaporator. Compressor, a condenser for condensing and liquefying the refrigerant compressed by the compressor, expansion means for expanding the liquefied refrigerant, and gas-liquid heat exchange for heat exchange between the gas refrigerant and the liquid refrigerant. Means, the gas-liquid heat exchange means comprises a low-pressure refrigerant pipe connecting the evaporator and the compressor and flowing a gas refrigerant, and a high-pressure refrigerant pipe connecting the condenser and the expansion means and a liquid refrigerant flowing therethrough. And the other pipe is spirally wound around the outer peripheral surface of one of the refrigerant pipes.

According to the refrigerating apparatus, since the other pipe is spirally wound around the outer peripheral surface of the one pipe, the gas flowing through one of the one pipe and the other pipe can be used. The heat exchange between the refrigerant and the liquid refrigerant is performed through one pipe and another pipe. Here, since the other pipes are spirally formed with respect to the outer peripheral surface of one pipe, the heat transfer area of both pipes is increased as compared with the case where the pipes are formed linearly, and the gas refrigerant and the liquid refrigerant are separated. The time and distance for heat exchange also increase. As a result, heat exchange between the liquid refrigerant and the gas refrigerant is sufficiently performed, the liquid refrigerant is supercooled, and the degree of superheat of the gas refrigerant is increased. Further, in the present refrigeration apparatus, the other pipe is formed into a spiral shape by bending, and is disposed on the outer peripheral surface of one pipe, whereby the gas-liquid heat exchange means is formed. For this reason, compared to a conventional gas-liquid heat exchanger having a complicated structure in which the fin tubes are disposed inside the shell and then the end plate portions are joined by welding, the production is facilitated, and the air-fuel ratio is increased. The liquid heat exchange means will be provided at low cost.

Further, the periphery of the other pipe is covered with a heat insulating material.

According to the refrigerating apparatus, the outer peripheral surface of one pipe is covered with another pipe, and the periphery of the other pipe is covered with a heat insulating material. Movement is suppressed. For this reason, the heat exchange between the gas refrigerant and the liquid refrigerant is performed more efficiently than in the case where the heat insulating material is not attached. As a result, the liquid refrigerant is further subcooled, and the degree of superheat of the gas refrigerant is further increased.

Further, the one pipe is the low-pressure refrigerant pipe, and the other pipe is the high-pressure refrigerant pipe.

According to the refrigeration apparatus described above, the high-pressure refrigerant pipe through which the liquid refrigerant flows is spirally wound around the low-pressure refrigerant pipe through which the gas refrigerant flows. The size of the pipe is determined by the state of the refrigerant, and is usually formed thicker in a low-pressure pipe that is gaseous and has a high flow rate, and thin in a high-pressure pipe that is liquid and has a low flow rate. When the high-pressure refrigerant pipe is processed into a spiral shape, the processing is easily performed.

Further, the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are made of copper pipe.

According to the refrigerating apparatus, the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are made of copper pipes, and the copper pipes have a higher thermal conductivity than steel pipes or the like. It will be performed efficiently. Further, since the copper pipe is excellent in extensibility, drawability, and the like, processing of the low-pressure refrigerant pipe and the high-pressure refrigerant pipe can be easily performed. Further, since the copper pipe is cheaper than the aluminum pipe or the like, the gas-liquid heat exchange means is provided at low cost.

Further, in the refrigerating apparatus according to any one of the above, the refrigerating apparatus for land transportation to be attached to a land transportation vehicle provided with a cold storage box for keeping a cooled product, wherein the evaporator and the expansion The means is provided inside the cool box, the compressor and the condenser are provided outside the cool box, and the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are outside the cool box and the evaporator and the expansion means. And the compressor and the condenser.

According to the above refrigeration system for land transportation, the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are connected to the evaporator and the expansion valve provided inside the cool box and the compressor and condenser provided outside the cool box. Since both pipes are provided between the two pipes, the pipes have a sufficient length for heat exchange between the gas refrigerant and the liquid refrigerant flowing inside the respective pipes.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a refrigeration apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, the present apparatus is mounted on a refrigerator car 1 provided with a refrigerator 2 and includes an evaporator unit 3, a condensing unit 4, a low-pressure refrigerant pipe 5, a high-pressure refrigerant The pipe 6 is a main component, and the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6 constitute a gas-liquid heat exchange unit. Low pressure refrigerant pipe 5 and high pressure refrigerant pipe 6
Extends from the evaporator unit 3 provided inside the cool box 2 and at the upper end on the operator's cab side to the condensing unit 4 provided at the lower outside of the cool box 2 and connects both units. More specifically, the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6 are connected from the evaporator unit 3 to the cold storage 2
After extending through the wall surface of the cool box 2 and being bent at a substantially right angle in the vertical direction. Further, both the pipes extend downward along the outer front portion of the cool box 2, and are bent at a substantially right angle again toward the rear of the cool box 2 at a lower portion (bottom) of the cool box 2. Then, it extends rearward along the bottom of the cool box 2 and reaches the condensing unit 4.

As shown in FIG. 2, the evaporator unit 3
Is provided with an evaporator 7, an evaporator fan 8, and an expansion valve (expansion means) 9. The condensing unit 4 includes a condenser 10 and a condenser fan 11
, A receiver 12, a dryer 13, an accumulator 14, and a compressor 15. The low-pressure refrigerant pipe 5 connects the evaporator 7 provided in the evaporator unit 3 and the compressor 15 via an accumulator 14 provided in the condensing unit 4. The high-pressure refrigerant pipe 6 connects the condenser 10 and the expansion valve 9 provided in the evaporator unit 3 via a dryer 13 provided in the condensing unit 4. The high-pressure refrigerant pipe 6
Is spirally wound around the low-pressure refrigerant pipe 5 at an outer portion of the evaporator unit 3 and the condensing unit 4.

Here, the detailed structure of the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6 is shown in FIG. As described above, the high-pressure refrigerant pipe 6 is spirally wound around the low-pressure refrigerant pipe 5 at least partially in contact therewith, and the periphery of the high-pressure refrigerant pipe 6 is covered with the heat insulating material 16. The low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6 are copper pipes.

According to the refrigerating apparatus having the above-described configuration, the operation is as follows. Compressor 1 of condensing unit 4 by the power of engine etc.
When the compressor 5 is driven, the high-pressure / low-temperature gas refrigerant compressed by the compressor 15 is sent to the condenser 10, where it is cooled by the outside air 50 introduced by the condenser fan 11 and condensed and liquefied. This liquid refrigerant is
2. After passing through the dryer 13, it is sent to the high-pressure refrigerant pipe 6 that connects the condensing unit 4 and the evaporator unit 3. On the other hand, the low-pressure / low-temperature gas refrigerant that has exchanged heat with the circulating air in the cold storage 2 in the evaporator 7 of the evaporator unit 3 is sent to the low-pressure refrigerant pipe 5 that connects the evaporator unit 3 and the condensing unit 4.
Here, the liquid refrigerant and the gas refrigerant flow inside the high-pressure refrigerant pipe 6 and the low-pressure refrigerant pipe 5, respectively, in opposite directions.
Heat exchange between the liquid refrigerant and the gas refrigerant is performed via both the pipes. For this reason, the liquid refrigerant is supercooled, and the gas refrigerant has an increased degree of superheat. The supercooled liquid refrigerant expands at the expansion valve 9 and then enters the evaporator 7, and in the process of flowing through the piping in the evaporator 7, circulates air and heat in the cool box 2 sent by the evaporator 7. Exchange. Thereby, the air is cooled and becomes the cooling air 60 by the evaporator fan 8 and is blown out into the cool box 2. On the other hand, the gas refrigerant having an increased degree of superheat is sent to the accumulator 16 and returns to the compressor 17 therefrom.

According to the above-described embodiment, the heat exchange between the gas refrigerant and the liquid refrigerant is performed while both refrigerants pass through the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6, respectively. This produces the following effects.

That is, by combining the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6 for circulating the refrigerant,
Since a gas-liquid heat exchange function is also provided, there is no need to separately install a gas-liquid heat exchanger as conventionally used. For this reason, the cost of the refrigeration apparatus can be significantly reduced. In addition, the present gas-liquid heat exchange means can perform sufficient and efficient heat exchange between the gas refrigerant and the liquid refrigerant, and does not adversely affect the refrigeration capacity of the refrigeration apparatus.

More specifically, a high-pressure refrigerant pipe 6 is spirally wound around the outer peripheral surface of the low-pressure refrigerant pipe 5. Thereby, the heat transfer area of both pipes can be effectively increased, and it is possible to form a time and a distance enough for the gas refrigerant and the liquid refrigerant to sufficiently exchange heat. In particular, in the refrigerator car 1 equipped with the cool box 2, the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 5 connecting the evaporator unit 3 provided on the upper inside of the cool box 2 and the condensing unit 4 provided on the lower outside of the cool box 2. The length of the refrigerant pipe 6 is about 4 m for a large truck and 2 m or more for a small truck. Therefore, it is possible to secure a heat transfer area, time, and distance sufficient for heat exchange between the gas refrigerant and the liquid refrigerant. Therefore, heat exchange between the liquid refrigerant and the gas refrigerant is sufficiently performed, the liquid refrigerant is supercooled, and the degree of superheat of the gas refrigerant is increased. Further, since the high-pressure refrigerant pipe 6 may be formed into a spiral shape by bending, a conventional fin tube having a complicated structure in which a fin tube is disposed inside the shell and the end plate portions are joined by welding. It can be easily manufactured as compared with a liquid heat exchanger. Therefore, it is possible to provide the refrigeration apparatus at low cost.

The outer peripheral surface of the low-pressure refrigerant pipe 5 is covered with a high-pressure refrigerant pipe 6, and the periphery of the high-pressure refrigerant pipe 6 is further covered with a heat insulating material 16. For this reason, heat transfer to the outside of both pipes can be suppressed. Thereby, the heat exchange between the gas refrigerant and the liquid refrigerant is performed more efficiently as compared with the case where the heat insulating material is not attached.

Further, the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6 are formed by copper pipes. Since the copper pipe has a higher thermal conductivity than a steel pipe or the like, heat exchange between the gas refrigerant and the liquid refrigerant is performed efficiently. Further, copper pipes are easy to process because they have excellent ductility and drawability, and are cheaper than aluminum pipes and the like, so that costs can be reduced.

In this embodiment, a high-pressure refrigerant pipe 6 through which a liquid refrigerant flows is spirally wound around a low-pressure refrigerant pipe 5 through which a gas refrigerant flows. The size of the pipe is determined by the state of the refrigerant, and is generally thick in a gaseous low-pressure pipe with a high flow rate, and thin in a liquid high-pressure pipe with a low flow rate. Accordingly, the processing of the high-pressure refrigerant pipe 6 in a spiral shape can be performed more easily than the processing of the low-pressure refrigerant pipe 5 in a spiral shape. In addition, this is advantageous because both pipes can be arranged compactly.

As described above, according to the present embodiment, the heat exchange between the gas refrigerant and the liquid refrigerant can be sufficiently and efficiently performed, so that the liquid refrigerant is supercooled and the gas refrigerant has an increased degree of superheat. Will be done. Therefore, a cycle consisting of A'-B'-C'-D 'similar to the case where the gas-liquid heat exchanger of the refrigerant Mollier chart (FIG. 7) is provided can be constituted, and the refrigerating capacity of the refrigerating apparatus can be formed. Will be improved.

The high-pressure refrigerant pipe 6 is fixed to the low-pressure refrigerant pipe 5 by, for example, partially brazing. The shape (number of turns, pitch, etc.) of the high-pressure refrigerant pipe 6 can be appropriately adjusted according to various conditions such as required refrigeration capacity and pipe length. For example, by forming the winding diameter (inner diameter) of the high-pressure refrigerant pipe 6 equal to the outer diameter of the low-pressure refrigerant pipe 5 and arranging both pipes so that the low-pressure refrigerant pipe 5 and the high-pressure refrigerant pipe 6 are in direct contact with each other, Heat exchange between the refrigerant and the gas refrigerant can be further promoted.

[0036]

According to the refrigerating apparatus of the present invention, since the other pipe is formed spirally with respect to the outer peripheral surface of one pipe, the heat transfer between the two pipes is made rather than being formed linearly. The area can be increased, and the time and distance for heat exchange between the gas refrigerant and the liquid refrigerant can be increased. Therefore, heat exchange between the liquid refrigerant and the gas refrigerant is sufficiently performed, the liquid refrigerant is supercooled, and the degree of superheat of the gas refrigerant is increased. In addition, since the other pipe is formed in a spiral shape by bending, a conventional structure having a complicated structure in which a fin tube is disposed inside the shell and the end plate portions are joined by welding. Can be easily manufactured as compared with the gas-liquid heat exchanger. Therefore, it is possible to provide the refrigeration apparatus at low cost.

Further, according to the present invention, the outer peripheral surface of one pipe is covered with another pipe, and the periphery of the other pipe is covered with a heat insulating material. Can be suppressed. Therefore, heat exchange between the gas refrigerant and the liquid refrigerant can be performed more efficiently as compared with the case where the heat insulating material is not attached. Thereby, the liquid refrigerant is further subcooled, and the degree of superheat of the gas refrigerant further increases.

Further, according to the present invention, the high-pressure refrigerant pipe through which the liquid refrigerant flows is spirally wound around the low-pressure refrigerant pipe through which the gas refrigerant flows. The size of the pipe is determined by the state of the refrigerant, and is usually formed thicker in a low-pressure pipe that is gaseous and has a high flow rate, and thin in a high-pressure pipe that is liquid and has a low flow rate. If the high-pressure refrigerant pipe is processed into a spiral shape, the processing can be easily performed. Further, both pipes can be arranged compactly.

Further, according to the present invention, the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are made of copper pipes, and the copper pipes have a higher thermal conductivity than steel pipes or the like. It is possible to perform the processing efficiently. Further, since the copper pipe is excellent in extensibility, drawability, etc., it is possible to easily process the low-pressure refrigerant pipe and the high-pressure refrigerant pipe. Furthermore, since copper piping is also cheaper than aluminum piping and the like, gas-liquid heat exchange means can be provided at low cost.

Further, according to the land transportation refrigeration apparatus of the present invention, the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are provided with an evaporator and an expansion valve provided inside the cool box, and a compressor and a condenser provided outside the cool box. Therefore, both pipes can be formed to have a sufficient length for the gas refrigerant and the liquid refrigerant flowing inside the respective pipes to perform heat exchange.

[Brief description of the drawings]

FIG. 1 is a side view of a land transportation vehicle equipped with a refrigeration apparatus according to an embodiment of the present invention.

FIG. 2 is a refrigerant piping system diagram illustrating an entire configuration of a refrigeration apparatus according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a detailed structure of a gas-liquid heat exchange unit according to the embodiment of the present invention.

FIG. 4 is an explanatory view of a land transportation vehicle equipped with a conventional refrigeration system.

FIG. 5 is a refrigerant piping system diagram showing the entire configuration of a conventional refrigeration apparatus.

FIG. 6 is an explanatory view showing a detailed structure of a conventional gas-liquid heat exchanger.

FIG. 7 is a refrigeration cycle diagram on a refrigerant Mollier chart.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Land transportation vehicle (freezer) 2 Cooler 3 Evaporator unit 4 Condensing unit 5 Low-pressure refrigerant pipe 6 High-pressure refrigerant pipe 7 Evaporator 8 Evaporator fan 9 Expansion valve 10 Capacitor 11 Condenser fan 12 Receiver 13 Dryer 14 Accumulator 15 Compressor 16 Heat insulation Lumber

Claims (5)

[Claims] An evaporator for supplying a refrigerant in a liquid phase to evaporate the refrigerant and cool an object to be cooled, a compressor for compressing the refrigerant gasified by the evaporator, and a compressor for compressing the refrigerant. A condenser for condensing and liquefying the liquefied refrigerant, expansion means for expanding the liquefied refrigerant, and gas-liquid heat exchange means for exchanging heat between the gas refrigerant and the liquid refrigerant. The liquid heat exchanging means includes a low-pressure refrigerant pipe connecting the evaporator and the compressor and flowing a gas refrigerant, and a high-pressure refrigerant pipe connecting the condenser and the expansion means and flowing a liquid refrigerant. A refrigeration apparatus, wherein another pipe is spirally wound around the outer peripheral surface of the pipe. 2. The refrigeration apparatus according to claim 1, wherein the periphery of said another pipe is further covered with a heat insulating material. 3. The refrigeration apparatus according to claim 1, wherein the one pipe is the low-pressure refrigerant pipe, and the other pipe is the high-pressure refrigerant pipe. 4. The refrigeration apparatus according to claim 1, wherein the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are made of copper pipes. 5. A land transportation refrigeration apparatus according to claim 1, wherein said refrigeration apparatus is mounted on a land transportation vehicle provided with a cold storage box for keeping a cooling object cool. The evaporator and the expansion unit are provided inside the cool box, the compressor and the condenser are provided outside the cool box, and the low-pressure refrigerant pipe and the high-pressure refrigerant pipe are outside the cool box. A refrigeration unit for land transportation provided between the evaporator and the expansion means and the compressor and the condenser.