JP2001349628A - Freezer machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a less-expensive freezer machine realizing a double-stage economizer cycle and showing a high freezing efficiency. SOLUTION: This freezer machine is integrally constituted by a condenser 16 for condensing and liquefying refrigerant; an intermediate cooler 18 temporarily storing the refrigerant liquefied at the condenser 16 and cooling it; a throttle valve 17 for reducing pressure of refrigerant liquefied at the condenser 16; an evaporator 14 for evaporating and gasifying the refrigerant of which pressure is reduced at the throttle valve 17; a compressor 15 for compressing refrigerant gasified at the evaporator 14 and gaseous component of the refrigerant cooled at the intermediate cooler 18; and a motor 20 for driving the compressor 15. The motor 20 is integrally formed with the intermediate cooler 18.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator provided in, for example, a large-scale air conditioning system. 2. Description of the Related Art In a large-scale structure such as a building, for example, chilled water cooled by a refrigerator is circulated through a pipe provided in the structure to exchange heat with air in a living room. To perform cooling. FIG. 3 shows an example of a refrigerator. The refrigerator shown in the figure includes an evaporator 1 that exchanges heat between a refrigerant and cold water to cool the cold water and evaporates and vaporizes the refrigerant, and a compressor 2 that compresses the refrigerant vaporized in the evaporator 1. A condenser 3 for exchanging heat between the refrigerant and the cooling water compressed in the compressor 2 to condense and liquefy the refrigerant;
A throttle valve 4 for reducing the pressure of the liquefied refrigerant, an intercooler 5 for temporarily storing and cooling the liquefied refrigerant in the condenser 3, and a part of the refrigerant cooled in the condenser 3 Cooler 6 that cools the lubricating oil of compressor 2
And A motor 7 for driving the compressor 2 is connected to the compressor 2. [0004] The evaporator 1, the compressor 2, the condenser 3, the throttle valve 4, and the intercooler 5 are connected by a main pipe 8 to constitute a closed system for circulating a refrigerant. The compressor 2 employs a two-stage centrifugal compressor, a so-called turbo compressor, and has a first-stage impeller 2a.
And compresses the refrigerant into the second stage impeller 2 b, compresses the refrigerant, and sends out the refrigerant to the condenser 3. The condenser 3 comprises a main condenser 3a and an auxiliary condenser 3b called a subcooler. The refrigerant is introduced in the order of the main condenser 3a and the subcooler 3b.
A part of the refrigerant cooled in the above is introduced into the oil cooler 6 through the branch pipe 8a without passing through the subcooler 3b, and cools the lubricating oil. Apart from that, a part of the refrigerant cooled in the main condenser 3a is introduced into the casing of the motor 7 through the branch pipe 8b without passing through the subcooler 3b, and cools the stator and the coil (see FIG. 4 for details). I do. The throttle valve 4 is disposed between the condenser 3 and the intercooler 5 and between the intercooler 5 and the evaporator 1, respectively. Reduce pressure. [0008] The structure of the intercooler 5 is equal to that of a hollow container, and is cooled in the main condenser 3a and the subcooler 3b.
The refrigerant depressurized by the throttle valve 4 is temporarily stored and further cooled. The gas phase component in the intercooler 5 is introduced into the second stage impeller 2b of the compressor 2 through the bypass pipe 13 without passing through the evaporator 1. FIG. 4 shows the internal structure of the motor 7. In the figure, reference numeral 7a denotes a casing, 9a denotes a stator, 9b denotes a coil, 10 denotes a rotor, 11 denotes a drive shaft, and the drive shaft 1
A gear mechanism 12 for driving the compressor 2 is provided at an output end of the compressor 1. The stator 9a is formed with an introduction hole 9c for guiding the refrigerant introduced from the condenser 3 to the boundary with the rotor 10, and the refrigerant passing through the introduction hole 9c is scattered by the rotation of the rotor 10 and partially dispersed. Cools the coil 9b. Both the refrigerant that has been sprayed and the refrigerant that has not contributed to the cooling of the coil 9b accumulate at the bottom of the casing 7a and are introduced into the evaporator 1 through the branch pipe 8c. [0011] The refrigerator configured as described above has the following problems. 1. In the refrigerator described above, a two-stage refrigeration cycle including a condenser 3 and an intercooler 5, that is, a so-called two-stage economizer cycle is realized in order to improve the refrigeration efficiency. This has contributed to a rise in manufacturing costs. 2. In the refrigerator described above, a part of the refrigerant is guided to the motor 7 to cool the motor 7, but since the liquefied refrigerant is sprayed to cool the coil 9b, the coil 9b is cooled. A large amount of refrigerant stays at the bottom of the casing 7a without contacting the casing 9b, and most of the refrigerant introduced into the casing 7a flows into the evaporator 1 without contributing to cooling of the stator 9a and the coil 9b. For this reason, a refrigerant several times as much as the amount having the heat energy (cold heat) necessary to actually cool the stator 9a and the coil 9b is introduced into the casing 7a. Most of this refrigerant flows into the evaporator 1 without passing through the intercooler 5, and is operated in a substantially single-stage refrigeration cycle instead of a two-stage economizer cycle, thereby improving refrigeration efficiency. Is a problem. The present invention has been made in view of the above circumstances, and has as its object to provide an inexpensive refrigerator with high refrigeration efficiency while realizing a two-stage economizer cycle. As means for solving the above-mentioned problems, a refrigerator having the following configuration is employed.
That is, the refrigerator according to claim 1 is a condenser that condenses and liquefies a refrigerant, an intermediate cooler that temporarily stores and cools the refrigerant liquefied in the condenser, and is liquefied in the condenser. A throttle valve that decompresses the refrigerant, an evaporator that evaporates and evaporates the refrigerant that has been depressurized by the throttle valve, and a gas phase component of the refrigerant that is cooled in the intercooler and vaporized in the evaporator. A refrigerator comprising a compressor for compressing the refrigerant and a motor for driving the compressor, wherein the motor is integrated with the intercooler. In this refrigerator, the manufacturing cost can be reduced and the refrigeration efficiency can be improved by integrating the intercooler with the motor. Specifically, since the intercooler has the same structure as a hollow container as described above, it is configured as a part of a motor, and by reducing the number of parts, the supply cost of parts and assembling by integrating both are reduced. The cost can be reduced. In addition, by using the refrigerant temporarily stored in the intercooler to cool the motor drive unit (coils, stators, etc.), the motor cooling refrigerant passes through the intercooler as in the conventional case. Therefore, there is no need to introduce the single-stage refrigeration cycle into the evaporator, and all the realized single-stage refrigeration cycles are switched to two-stage economizer cycles, thereby improving refrigeration efficiency. According to a second aspect of the present invention, in the refrigerator of the first aspect, the motor includes a casing integrated with the intercooler, a stator fixed to the casing, and a center of the stator. A rotating shaft rotatably supported on the rotating shaft, and a rotor fixed to the rotating shaft, wherein the casing has a bypass pipe for introducing a gas phase component of the refrigerant present in the casing to the compressor. Is provided. In this refrigerator, the gas phase component of the refrigerant present in the casing integrated with the intercooler is
It is introduced into the compressor through the bypass pipe without passing through the evaporator. As a result, the vapor phase component of the refrigerant is not introduced into the evaporator, and the refrigerant in the evaporator becomes almost a liquid phase component, and the effects of evaporation and vaporization are promoted, so that the refrigeration efficiency can be improved. According to a third aspect of the present invention, in the refrigerator according to the first or second aspect, the condenser is liquefied between the condenser and the motor in which the intercooler is integrated. An oil cooler that cools lubricating oil of the compressor by using a part of the refrigerant is provided. In this refrigerator, when an oil cooler is employed, the refrigerant that has contributed to the cooling of the lubricating oil is also introduced into the intermediate cooler without using a single-stage refrigeration cycle. Is realized, so that the refrigeration efficiency can be improved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a refrigerator according to the present invention will be described with reference to FIGS. FIG. 1 shows the configuration of the refrigerator in the present embodiment. The refrigerator shown in the figure includes an evaporator 14 that exchanges heat between a refrigerant and cold water to cool the cold water and evaporates and vaporizes the refrigerant, and a compressor 15 that compresses the refrigerant vaporized in the evaporator 14. And the compressor 15
A condenser 16 for exchanging heat between the refrigerant and the cooling water to condense and liquefy the refrigerant, a throttle valve 17 for reducing the pressure of the refrigerant liquefied in the condenser 16, and a liquefaction in the condenser 16 An intermediate cooler 18 for temporarily storing and cooling the cooled refrigerant, and an oil cooler 19 for cooling the lubricating oil of the compressor 15 by utilizing a part of the refrigerant cooled in the condenser 16. I have. A motor 20 for driving the compressor 15 is connected to the compressor 15. In this embodiment, the motor 20 is integrated with the intercooler 18, and the evaporator 14, the compressor 15, the condenser 16, the throttle valve 17, and the intercooler 18
The motor 20 integrated with the main pipe 21 is connected by a main pipe 21 to form a closed system for circulating the refrigerant. The evaporator 14 is connected to a chilled water pipe 22 for introducing chilled water as a chilled heat source used for air conditioning. The chilled water flows through the chilled water pipe 22 and the refrigerant introduced to the evaporator 14. The heat is exchanged in the refrigerant, and the refrigerant is evaporated and vaporized, and the cold water is cooled by giving heat energy to the refrigerant. The compressor 15 employs a two-stage centrifugal compressor, a so-called turbo compressor.
5a compresses the gas refrigerant and transfers the refrigerant to the second stage impeller 15
and then sent to the condenser 16 after being further compressed. The condenser 16 comprises a main condenser 16a and a subcooler 16b.
a, the refrigerant is introduced in the order of the subcooler 16b. A cooling water pipe 23 for introducing cooling water from a supply source (not shown) is connected to the main condenser 16a and the subcooler 16b, and heat exchange between the refrigerant introduced into the main condenser 16a and the subcooler 16b and the cooling water. The refrigerant is condensed and liquefied,
The cooling water is heated by the heat energy of the refrigerant. A part of the refrigerant cooled in the main condenser 16a is introduced into the oil cooler 19 without passing through the subcooler 16b. The oil cooler 19 includes a main condenser 16a.
And a branch pipe 24 for extracting a part of the refrigerant from between the oil cooler 16b and the subcooler 16b and introducing the refrigerant to the intercooler 18 or the motor 20 via the oil cooler 19; The pipe 25 is connected, heat exchange is performed between the refrigerant introduced into the oil cooler 19 and the lubricating oil, the lubricating oil is cooled, and the refrigerant is given the heat energy of the lubricating oil and heats up. I do. The throttle valve 17 is disposed between the subcooler 16b and the motor 20, and between the motor 20 and the evaporator 14, and decompresses the refrigerant liquefied in the condenser 3 in a stepwise manner. The motor 2 integrated with the intercooler 18
0 is shown in FIG. In the figure, reference numeral 20a is a casing, 26a is a stator, 26b is a coil, 27 is a rotor, 28 is a drive shaft, and a gear mechanism 29 for driving the compressor 15 is provided at an output end of the drive shaft 28. As described above, the structure of the intercooler 18 is equivalent to a hollow container, and its function is substituted by the casing 20a. Therefore, the main pipe 21 for introducing the refrigerant into the motor 20 is connected to the upper part of the casing 20a, and the main pipe 2 for introducing the refrigerant from the casing 20a to the evaporator 14.
1 is connected to the bottom of the casing 20a. A bypass pipe 30 is provided between the casing 20a and the compressor 15 for introducing the gas phase component of the refrigerant present in the casing 20a into the compressor 15. The gas phase component of the refrigerant introduced into the compressor 15 through the bypass pipe 30 is introduced into the second stage impeller 15b. The flow of the refrigerant in the refrigerator configured as described above will be described step by step. First, a low-temperature and low-pressure refrigerant (hereinafter, referred to as a gas refrigerant) evaporated and vaporized in the evaporator 14 is introduced into a first stage impeller 15a of a compressor 15 and compressed, and then is compressed into a second stage impeller 15b. And further compressed. The gas refrigerant which has been compressed in the compressor 15 and has become high temperature and high pressure is introduced into the main condenser 16a, where it is condensed and liquefied by exchanging heat with cooling water.
When introduced into b, condensation and liquefaction are further promoted to become a high-temperature and high-pressure liquid refrigerant. Note that part of the liquid refrigerant that has passed through the main condenser 16a is not introduced into the subcooler 16a, and
The lubricating oil is cooled and then introduced into the motor 20. The high-temperature and high-pressure liquid refrigerant condensed and liquefied in the condenser 16 is reduced in pressure by the throttle valve 17a to become a low-temperature and low-pressure liquid refrigerant. The decompression of the refrigerant is stepwisely advanced by the throttle valve 17a and another throttle valve 17b provided downstream of the motor 20. The low-temperature and low-pressure liquid refrigerant depressurized by the throttle valve 17a is introduced into the casing 20a of the motor 20, and is temporarily stored and cooled together with the refrigerant contributing to the cooling of the lubricating oil through the branch pipe 24. After that, it is introduced into the evaporator 14. Further, the gas phase component of the refrigerant present in the casing 20a contributes to the cooling of the coil 26b, and thereafter, is introduced into the second impeller 15b of the compressor 15 through the bypass pipe 30, and is compressed in the first impeller 15a. It is compressed together with the refrigerant. The low-temperature and low-pressure liquid refrigerant introduced into the evaporator 14 exchanges heat with the cold water to cool the cold water, evaporates and vaporizes itself, and thereafter repeats the above-described refrigeration cycle. In the refrigerator configured as described above, by integrating the intercooler 18 with the motor 20, the production cost can be reduced and the refrigeration efficiency can be improved as compared with the case where both are manufactured separately. realizable. Since the intercooler 18 has the same structure as a hollow container as described above, the intercooler 18 is integrally formed with the casing 20a of the motor 20 to reduce the number of parts, thereby reducing the supply cost of parts and the assembly cost due to the integration of both. The reduction is possible. Also,
In the conventional motor, a hole is provided in the stator to spray the refrigerant introduced into the casing, but in this embodiment, the stator 26a, the coil 26b, and the rotor 27 are cooled by the refrigerant vaporized in the casing 20a. No processing is required for the stator 26a itself, and processing time and cost are not required. Further, by utilizing the refrigerant temporarily stored in the casing 20a, the stator 26a and the coil 26 are used.
b. By cooling the rotor 27, it is no longer necessary to introduce the motor cooling refrigerant into the evaporator without passing through the intercooler as in the prior art, and the single-stage refrigeration cycle that has been substantially realized is completely eliminated. By switching to a two-stage economizer cycle, refrigeration efficiency can be improved. In this embodiment, the condenser 16
Although the main condenser 16a and the subcooler 16b are provided as an example, the subcooler 16b may be omitted if unnecessary. If the oil cooler 19 is not required, the branch piping 24
It may be abolished with. Further, regarding the cooling of the motor 20,
In addition to the method using the vaporized refrigerant as described above, the throttle valve 1
There is a method in which the liquid refrigerant decompressed by 7a is guided to the outer periphery of the stator 26a and cooled, and the coil 26b is cooled by the liquid refrigerant flowing out from both ends. As described above, according to the refrigerator of the first aspect of the present invention, the number of parts is reduced by integrating the intercooler with the motor. Supply cost as well as assembly costs due to the integration of the two. In addition, by using the refrigerant temporarily stored in the intercooler to cool the drive unit of the motor, refrigerant for cooling the motor is introduced into the evaporator without passing through the intercooler as in the past. Need to be performed, and a two-stage economizer cycle is realized for all refrigerants.
The refrigeration efficiency can be improved. According to the refrigerator of the second aspect, by providing the bypass pipe for introducing the gas phase component of the refrigerant present in the casing to the compressor, the gas phase component of the refrigerant is not introduced into the evaporator. Since the refrigerant in the evaporator almost becomes a liquid phase component and the action of evaporation and vaporization is promoted, the refrigeration efficiency can be improved. According to the third aspect of the present invention, even when an oil cooler is employed, the refrigerant contributing to the cooling of the lubricating oil is introduced into the intermediate cooler without forming a single-stage refrigeration cycle. Since a two-stage economizer cycle is realized, the refrigeration efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing an embodiment of a refrigerator according to the present invention. FIG. 2 is a cross-sectional view illustrating an internal structure of a motor that drives a compressor included in the refrigerator according to the present invention. FIG. 3 is a schematic configuration diagram illustrating an example of a conventional refrigerator. FIG. 4 is a cross-sectional view illustrating an internal structure of a motor that drives a compressor included in a conventional refrigerator. [Description of Signs] 14 Evaporator 15 Compressor 16 Condenser 17 Throttle valve 18 Intercooler 19 Oil cooler 20 Motor 20a Casing 30 Bypass piping

Claims (1)

Claims: 1. A condenser for condensing and liquefying a refrigerant, an intercooler for temporarily storing and cooling the refrigerant liquefied in the condenser, and a refrigerant liquefied in the condenser. A throttle valve that decompresses the refrigerant, an evaporator that evaporates and vaporizes the refrigerant that is depressurized by the throttle valve, and a vapor phase component of the refrigerant that is cooled in the intercooler and vaporized in the evaporator. A refrigerator comprising: a compressor for compressing the refrigerant; and a motor for driving the compressor, wherein the motor is integrated with the intercooler. 2. A motor comprising: a casing integrated with the intercooler; a stator fixed to the casing; a rotating shaft rotatably supported at the center of the stator; The refrigeration system according to claim 1, further comprising a fixed rotor, wherein the casing is provided with a bypass pipe that introduces a gas phase component of the refrigerant present in the casing into the compressor. Machine. 3. The lubricant of the compressor is cooled by using a part of the refrigerant liquefied in the condenser between the condenser and the motor integrated with the intercooler. 3. The refrigerator according to claim 1, further comprising an oil cooler.