JP4240715B2 - Refrigeration equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigerator-freezer equipped with two compression elements and two evaporators.
[0002]
[Prior art]
In recent years, refrigerator-freezers equipped with a refrigerator compartment and a freezer compartment have been required to save energy and improve the accuracy of temperature control in each cabinet. Among them, a refrigerator-freezer system that includes two compression elements, two evaporators, a gas-liquid separator, and the like and forms a two-stage compression refrigeration cycle to save energy has been proposed.
[0003]
An example of such a refrigerator-freezer system is shown in US Pat. No. 4,910,972.
[0004]
Hereinafter, the conventional refrigerator-freezer system will be described with reference to the drawings.
[0005]
FIG. 5 is a refrigerant circuit diagram of a conventional two-stage compression refrigeration cycle. FIG. 6 is a sectional view of a gas-liquid separator used in a conventional two-stage compression refrigeration cycle.
[0006]
5 and 6, 1 is a first expansion valve, 2 is a freezer evaporator, 3 is a low stage compressor, 4 is a high stage compressor, 5 is a condenser, 6 is a second expansion valve, and 7 is refrigerated. These are room evaporators, which are connected by a pipe 8 in sequence. Reference numeral 9 denotes a gas-liquid separator 9 provided between the cold room evaporator 7 and the first expansion valve 1 and performing intermediate cooling between the low-stage compressor 3 and the high-stage compressor 4. A refrigerator system having a freezer compartment and a refrigerator compartment is formed. The gas-liquid separator 9 includes a main body container 10 and an inlet 11 provided at the upper part thereof, an outlet 12 provided at an intermediate part, an outlet 13 provided at the lower part, and a net 14. A refrigerant is stored as a liquid refrigerant 15 in the lower part of the gas-liquid separator 9, and a refrigerant is stored as a saturated gas in the upper part.
[0007]
The operation of the refrigerator-freezer system configured as described above will be described below.
[0008]
When the low stage compressor 3 is operated, the low stage compressor 3 sucks and compresses the refrigerant gas and discharges it to the pipe 8. The refrigerant gas discharged from the low stage compressor 3 to the pipe 8 is mixed with the refrigerant gas from the outlet 12 of the gas-liquid separator 9 and is sucked from the suction side of the high stage compressor 4 and compressed again. The refrigerant gas compressed by the high stage compressor 4 is sent to the condenser 5 through the pipe 8. In the condenser 5, the refrigerant gas dissipates heat and is condensed to form a liquid refrigerant, and then the pressure is reduced by the second expansion valve 6. And it flows into the evaporator 7 for refrigerator compartments, and a part is evaporated there. At this time, by taking heat away from the surroundings, the refrigerator for a refrigerator compartment 7 exhibits a cooling action and cools the refrigerator compartment. The gas-liquid two-phase refrigerant exiting the refrigerator compartment evaporator 7 flows into the gas-liquid separator 9 from the inlet 11, and solid impurities are removed by the net 14. And the liquid refrigerant 15 is stored in the bottom part in the gas-liquid separator 9, the saturated gas refrigerant is stored in the upper part in the gas-liquid separator 9, and a gaseous phase and a liquid phase are isolate | separated. Then, only the liquid refrigerant flows out from the outlet 13 of the gas-liquid separator 9 in the direction of the first expansion valve 1, where it is decompressed and flows into the freezer compartment evaporator 2 to evaporate. At this time, by taking heat away from the surroundings, the freezer compartment evaporator 2 exhibits a cooling action and cools the freezer compartment. Then, the low-temperature gas refrigerant that has left the freezer compartment evaporator 2 is again sucked into the low-stage compressor 3.
[0009]
On the other hand, the saturated gas refrigerant in the upper part of the gas-liquid separator 9 flows out from the outlet 12, mixes with the refrigerant gas discharged from the low-stage compressor 3, and lowers the temperature of the refrigerant gas sucked by the high-stage compressor 4, Efficiency can be improved. Moreover, since the temperature of the discharge gas of the high stage compressor 4 is also reduced, overheating of the compressor can be prevented, and poor lubrication and deterioration of the lubricating oil due to a decrease in the viscosity of the lubricating oil can be prevented.
[0010]
Thus, the two-stage compression refrigeration cycle has a theoretical efficiency higher than that of the one-stage compression refrigeration cycle, and the reliability of the compressor is improved.
[0011]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, the low-stage compressor 3 has a small compression ratio, so the theoretical compression power is small. However, the actually required shaft power is a sliding loss that is fixedly generated by the low-stage compressor 3 and the like. Will be quite big for. That is, since the total adiabatic efficiency, which is the ratio of the theoretical compression power to the shaft power, is deteriorated, there is a drawback that the efficiency of the actual refrigeration cycle may be considerably worse than the efficiency of the theoretical refrigeration cycle.
[0012]
An object of the present invention is to solve the conventional problems, and to improve the overall heat insulation efficiency of a compressor, improve the efficiency of an actual refrigeration cycle, and provide a highly efficient refrigeration apparatus with low power consumption. And
[0013]
In the above conventional configuration, since the refrigerant circulating in the cycle is in the order of cooling the freezer compartment after cooling the refrigerator compartment, particularly when the balance of the cooling load between the freezer compartment and the refrigerator compartment is changed, When the cooling load increases, the freezer compartment has a disadvantage that the refrigerating capacity becomes insufficient and the efficiency of the refrigerating cycle may deteriorate.
[0014]
Another object of the present invention is to ensure that either one of the refrigerators in the different temperature zones such as the freezer compartment and the refrigerator compartment of the freezer / refrigerator is not refrigerating capacity is insufficient or the refrigerating capacity is not excessive. It is an object of the present invention to provide a refrigeration and refrigeration apparatus that can be cooled rapidly and that has high efficiency and low power consumption.
In addition, since the above conventional configuration cannot cool only one of the freezer compartment evaporator 2 or the refrigerator compartment evaporator 7, when performing defrosting to prevent the performance of the evaporator from deteriorating, the freezer compartment and the refrigerator compartment are provided. Both cooling of these had to be stopped, and there existed a fault that the temperature in each store | warehouse | chamber might rise during performing the defrosting.
Another object of the present invention is to prevent the rise of the internal temperature by stopping the cooling of only one side when defrosting the evaporator for high temperature (for refrigerator compartment) or the evaporator for low temperature (for freezer compartment). It is providing the freezing and refrigeration apparatus which can do.
Further, in the above conventional configuration, since the low-stage compressor 3 and the high-stage compressor 4 are connected in series, the maximum capacity of the compressor is reduced compared to the compressor of the same size that is connected in parallel, and the door is opened and closed. It is not possible to cope with a significant increase in the cooling load in the freezer or refrigerated room due to the difference in the food to be stored in the storage, and the temperature in each part of the storage may become uneven or the internal temperature may rise. There was a fault that there was a nature.
[0015]
Another object of the present invention is to respond to changes in the cooling load in the freezer and refrigerator compartments, to achieve uniform temperature in each part of the refrigerator, and to cope with a significant increase in cooling loads in the freezer and refrigerator compartments. Another object of the present invention is to provide an efficient refrigeration apparatus capable of rapid cooling.
[0016]
[Means for Solving the Problems]
To achieve this object, the present invention includes a first compression element, a second compression element, a condenser connected together with a discharge side of the first compression element and a discharge side of the second compression element, and the condensation A first expansion device piped to the outlet side of the vessel, a high temperature evaporator piped to the outlet side of the first expansion device, and between the high temperature evaporator and the suction side of the first compression element A gas-liquid separator connected by piping, a second expansion device connected by piping to the gas-liquid separator, and a low-temperature evaporator connected by piping between the second expansion device and the suction side of the second compression element; The liquid refrigerant outlet side of the gas-liquid separator and the second expansion device communicate with each other, and the gas refrigerant outlet side of the gas-liquid separator and the first compression element communicate with each other.
[0017]
Thereby, the overall heat insulation efficiency of the compressor can be improved, the efficiency of the actual refrigeration cycle can be improved, and a highly efficient refrigeration apparatus with low power consumption can be provided.
[0018]
In addition, the present invention is configured to include a first bypass passage communicating the inlet side and the outlet side of the high-temperature evaporator, and a first on-off valve provided in the first bypass passage.
[0019]
As a result, one of the refrigerators in different temperature zones such as the freezer compartment and the refrigerator compartment of the freezer / refrigerator can be properly cooled without refrigeration capacity becoming insufficient or refrigeration capacity being excessive, and A refrigeration apparatus with high efficiency and low power consumption can be provided.
[0020]
Further, the present invention is provided between the second on-off valve provided between the branch point of the first bypass passage and the high-temperature evaporator, and between the gas-liquid separator and the suction side of the second compression element. The third open / close valve is provided.
[0021]
Thereby, when performing defrosting of the high-temperature evaporator or the low-temperature evaporator, it is possible to provide a freezing and refrigeration apparatus capable of stopping the cooling of only one side and preventing the internal temperature from rising.
[0022]
The present invention also provides a second bypass passage communicating the suction side of the first compression element and the suction side of the second compression element, a fourth on-off valve provided in the second bypass passage, and the first compression The fifth open / close valve is provided between the element and the gas-liquid separator.
[0023]
As a result, the temperature of each part in the refrigerator can be made uniform in response to changes in the cooling load in the freezer and refrigerator compartments, and the cooling load in the freezer compartment and refrigerator compartment can be significantly increased and rapid cooling can be performed. It is possible to provide an efficient freezing and refrigeration apparatus that can handle the above.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention includes a first compression element, a second compression element, a condenser connected together with a discharge side of the first compression element and a discharge side of the second compression element, and the A first expansion device piped to the outlet side of the condenser, a high temperature evaporator piped to the outlet side of the first expansion device, and between the high temperature evaporator and the suction side of the first compression element A gas-liquid separator connected to the pipe, a second expansion device connected to the gas-liquid separator, and a low-temperature evaporator connected between the second expansion device and the suction side of the second compression element The liquid refrigerant outlet side of the gas-liquid separator communicates with the second expansion device, and the gas refrigerant outlet side of the gas-liquid separator communicates with the first compression element. The circuit for high temperature and the circuit for low temperature are formed as separate single-stage compression cycles, respectively. By operating at the proper pressure conditions as not to shrink ratio, it is possible to prevent the overall adiabatic efficiency. Therefore, it has the effect of improving the efficiency of the actual refrigeration cycle and reducing power consumption.
[0025]
Furthermore, is obtained by a first bypass passage communicating the inlet side and the outlet side of the high temperature evaporator, a configuration in which a first shut-off valve provided in the first bypass passage, refrigerating and freezing compartment When the cooling load on the low-temperature side in the chamber in different temperature zones becomes relatively large, the refrigerant flows mainly through the first bypass passage rather than the high-temperature evaporator by opening the first on-off valve. The cooling capacity is mainly exhibited in the freezer compartment (low temperature side) low temperature evaporator. Therefore, because it can cope with the imbalance between the cooling loads of the freezing room and the refrigerating room, one of them can be properly cooled without high cooling capacity or excessive freezing capacity, and high efficiency. This has the effect of reducing power consumption.
[0026]
Furthermore , a second on-off valve provided between the branch point of the first bypass passage and the high-temperature evaporator, and a third on-off valve provided between the gas-liquid separator and the suction side of the second compression element is obtained by the structure having the door, first on-off valve, opened third on-off valve, by closing the second shut-off valve, the refrigerant flows into the first bypass passage without flowing into the hot evaporator side The cooling capacity is exerted only on the low temperature evaporator on the freezer compartment side (low temperature side). Accordingly, it is possible to cope with a large imbalance between the cooling loads of the freezing room and the refrigerating room, and further, it is possible to defrost the high-temperature evaporator in which the cooling action is stopped while performing the cooling action with the low-temperature evaporator. Further, by opening the second on-off valve and closing the first on-off valve and the third on-off valve, the refrigerant passes through the high-temperature evaporator and flows into the gas-liquid separator, and then does not flow to the low-temperature evaporator side. Since the air is sucked into one compression element, the cooling capacity is exerted only on the high temperature evaporator on the refrigerator compartment side (high temperature side). Therefore, it is possible to cope with a large imbalance between the cooling loads of the freezing room and the refrigerating room, and further, it is possible to defrost the low-temperature evaporator in which the cooling action is stopped while performing the cooling action with the high-temperature evaporator. Has an effect.
[0027]
Furthermore, a second bypass passage communicating the suction side of the first compression element and the suction side of the second compression element, a fourth on-off valve provided in the second bypass passage, the first compression element and the gas-liquid is obtained by a structure in which a fifth on-off valve provided between the separator and the fourth on-off valve, by opening the fifth on-off valve, the suction side of the first compression element and the second compression element Since it is in communication and becomes a two-cylinder parallel one-stage compression operation, the refrigerant exhibits a cooling action in the high-temperature evaporator, and then is sucked into the first compression element and the second compression element without flowing to the low-temperature evaporator side. Rapid cooling operation on the refrigerator compartment side (high temperature side). In addition, by opening the first on-off valve and the fourth on-off valve and closing the fifth on-off valve, the suction side of the first compression element and the second compression element communicate with each other to perform a two-cylinder parallel one-stage compression operation, and the refrigerant is hot Since it flows to the first bypass passage without flowing to the evaporator side and exhibits its cooling capacity only to the low temperature evaporator on the freezer side (low temperature side), the rapid cooling operation on the freezer side is performed. That is, it is possible to equalize the temperature of each part in the freezer compartment and the refrigerator compartment, and to cope with a significant increase in the cooling load of the freezer compartment and the refrigerator compartment, and to perform rapid cooling. Has the effect of being able to
[0028]
【Example】
Embodiments of the freezing and refrigeration apparatus according to the present invention will be described below with reference to the drawings. In addition, about the same structure as the past, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
[0029]
( Reference Example 1 )
FIG. 1 is a refrigerant circuit diagram of a refrigerating and refrigerating apparatus according to Reference Example 1 . FIG. 2 is a pressure-enthalpy diagram of the refrigeration cycle in the refrigeration apparatus of the reference example .
[0030]
In FIGS. 1 and 2, 16 is a first compression element, 17 is a second compression element, and the first compression element 16 and the second compression element 17 are housed in a sealed container 18. Reference numeral 19 denotes a condenser connected together with the discharge side of the first compression element 16 and the discharge side of the second compression element 17. Reference numeral 20 denotes a first expansion device connected to the outlet side of the condenser 19 by piping, and reference numeral 21 denotes a high-temperature evaporator connected to the outlet side of the first expansion device 20 by piping. 22 is a gas-liquid separator connected by piping between the high-temperature evaporator 21 and the suction side of the first compression element 16, 23 is a second expansion device connected by piping to the gas-liquid separator 22, and 24 is This is a low-temperature evaporator connected by piping between the second expansion device 23 and the suction side of the second compression element 17. The liquid refrigerant outlet 25 side of the gas-liquid separator 22 communicates with the second expansion device 23, and the gas refrigerant outlet 26 side of the gas-liquid separator 22 communicates with the first compression element 16.
[0031]
The operation of the refrigeration apparatus configured as described above will be described below.
[0032]
When the first compression element 16 and the second compression element 17 are operated, they suck and compress the refrigerant gas, and are sent to the condenser 19 via the pipe. The refrigerant gas is radiated and condensed by the condenser 19 to become a liquid refrigerant, and then the pressure is reduced by the first expansion valve 20. Then, it flows into the high-temperature evaporator 21 and part thereof evaporates there. At this time, by removing heat from the surroundings, the high-temperature evaporator 21 exhibits a cooling action, and cools the inside of the high-temperature side storage such as the refrigerator compartment. The gas-liquid two-phase refrigerant that has exited the high-temperature evaporator 21 flows into the gas-liquid separator 22, and liquid refrigerant is stored at the bottom of the gas-liquid separator 22. Saturated gas refrigerant accumulates and the gas phase and liquid phase are separated. Then, only the liquid refrigerant flows out from the liquid refrigerant outlet 25 of the gas-liquid separator 22 in the direction of the second expansion device 23, where the pressure is reduced and flows into the low-temperature evaporator 24 to evaporate. At this time, by taking heat away from the surroundings, the low-temperature evaporator 24 exhibits a cooling action and cools the inside of the low-temperature side compartment such as the freezer compartment. Then, the low-temperature gas refrigerant that has exited the low-temperature evaporator 24 is sucked into the second compression element 17 again. On the other hand, the saturated gas refrigerant in the upper part of the gas-liquid separator 22 flows out from the gas refrigerant outlet 26 and is sucked into the second compression element 16 again.
[0033]
In this way, the high-temperature circuit and the low-temperature circuit are formed as separate single-stage compression cycles, and the operation is performed under an appropriate pressure condition that does not result in an extremely low compression ratio such as two-stage compression. Can be prevented. Therefore, the efficiency of the actual refrigeration cycle can be improved and the power consumption can be reduced.
[0034]
As described above, the refrigerating and refrigerating apparatus according to the present reference example includes the first compression element 16, the second compression element 17, the condenser connected together with the discharge side of the first compression element 16 and the discharge side of the second compression element 17. 19, a first expansion device 20 piped to the outlet side of the condenser 19, a high temperature evaporator 21 piped to the outlet side of the first expansion device 20, a high temperature evaporator 21, and the first compression element 16. A gas-liquid separator 22 connected to the suction side of the gas, a second expansion device 23 connected to the gas-liquid separator 22, and a space between the second expansion device 23 and the suction side of the second compression element 17. A low-temperature evaporator 24 connected to a pipe, the liquid refrigerant outlet 25 side of the gas-liquid separator 22 and the second expansion device 23 communicate with each other, and the gas refrigerant outlet 26 side of the gas-liquid separator 22 and the first compression Since the element 16 is in communication with each other, the high temperature circuit and the low temperature circuit are connected to each other. Each formed as separate stage compression cycle, by operating at an appropriate pressure conditions as not to extremely low compression ratio such as a two-stage compression, it is possible to prevent the overall adiabatic efficiency. Therefore, the efficiency of the actual refrigeration cycle can be improved and the power consumption can be reduced.
[0035]
( Reference Example 2 )
FIG. 3 is a refrigerant circuit diagram of the refrigerating / refrigeration apparatus according to Reference Example 2 .
[0036]
The following description will be made with reference to the drawings. The same components as those in Reference Example 1 will be assigned the same reference numerals and detailed description thereof will be omitted. In FIG. 3, reference numeral 27 denotes a first bypass passage that communicates the inlet side and the outlet side of the high-temperature evaporator 19, and 28 denotes a first on-off valve provided in the first bypass passage 27. 29 is a second on-off valve provided between the branch point of the first bypass passage 27 and the high-temperature evaporator 21, and 30 is between the gas-liquid separator 22 and the suction side of the second compression element 16. It is the 3rd on-off valve provided.
[0037]
The operation of the refrigeration apparatus configured as described above will be described below.
[0038]
When the first on-off valve 28 is closed, the second on-off valve 29 and the third on-off valve 30 are opened and the first compression element 16 and the second compression element 17 are operated, the same refrigeration cycle as in Reference Example 1 is formed and the same effect is obtained. Is obtained.
[0039]
From this state, when the cooling load on the low temperature side in the refrigerators in different temperature zones such as the freezer compartment and the refrigerator compartment becomes relatively large, the first on-off valve 28 is opened so that the refrigerant is from the high temperature evaporator 21. However, the cooling capacity mainly flows through the first bypass passage 28, and the cooling capacity thereof is mainly exhibited by the low temperature evaporator 24 on the freezer compartment side (low temperature side). Therefore, it is possible to cope with the imbalance between the cooling loads of the freezer compartment and the refrigerator compartment, so that either of them can be properly cooled without causing the freezing capacity to be insufficient or the freezing capacity to be excessive. Power consumption can be reduced.
[0040]
Further, by opening the first on-off valve 28 and the third on-off valve 30 and closing the second on-off valve 29, the refrigerant does not flow to the high temperature evaporator 21 side but flows to the first bypass passage 27, and its cooling capacity Is exerted only on the low-temperature evaporator 24 on the freezer compartment side (low-temperature side). Therefore, it is possible to cope with a large imbalance between the cooling loads of the freezing room and the refrigerating room, and furthermore, while the cooling operation is performed by the low temperature evaporator 24, the high temperature evaporator 21 in which the cooling operation is stopped can be defrosted. it can.
[0041]
Further, by opening the second on-off valve 29 and closing the first on-off valve 28 and the third on-off valve 30, the refrigerant flows into the gas-liquid separator 22 through the high temperature evaporator 21, and then the low temperature evaporator 24. Since it does not flow to the side and is sucked into the first compression element 16, the cooling capacity is exerted only on the high-temperature evaporator 21 on the refrigerator compartment side (high temperature side). Therefore, it is possible to cope with a large imbalance between the cooling loads of the freezing room and the refrigerating room, and it is possible to defrost the low-temperature evaporator 24 whose cooling action is stopped while performing the cooling action with the high-temperature evaporator 21. it can.
[0042]
As described above, the refrigerating and refrigerating apparatus of the present reference example includes the first bypass passage 27 that communicates the inlet side and the outlet side of the high-temperature evaporator 21, and the first on-off valve 28 provided in the first bypass passage 27. The second on-off valve 29 provided between the branch point of the first bypass passage 27 and the high-temperature evaporator 21, and provided between the gas-liquid separator 22 and the suction side of the second compression element 17. Since the third open / close valve 30 is provided, either one of the freezer compartment and the refrigerator compartment in different temperature zones such as the freezer is insufficient in refrigerating capacity or excessive in refrigerating capacity. Therefore, the interior of each cabinet can be properly cooled, and power consumption can be reduced with high efficiency. Further, when defrosting the high-temperature evaporator 21 or the low-temperature evaporator 24, the cooling of only one side can be stopped to prevent the internal temperature from rising.
[0043]
( Example 1 )
FIG. 4 is a refrigerant circuit diagram of the refrigeration apparatus according to Embodiment 1 of the present invention.
[0044]
The following description will be made with reference to the drawings. The same components as those in Reference Example 1 and Reference Example 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. In FIG. 4, 31 is a second bypass passage that communicates the suction side of the first compression element 16 and the suction side of the second compression element 17, and 32 is a fourth on-off valve provided in the second bypass passage 31. And 33 is a fifth on-off valve provided between the first compression element 16 and the gas-liquid separator 22.
[0045]
The operation of the refrigeration apparatus configured as described above will be described below.
[0046]
When the fourth on-off valve 32 is closed and the fifth on-off valve 33 is opened and the first compression element 16 and the second compression element 17 are operated, the same effect as in Reference Example 2 is obtained.
[0047]
Then, by closing the first on-off valve 28 and the third on-off valve 30 and opening the second on-off valve 29, the fourth on-off valve 32, and the fifth on-off valve 33, the first compression element 16 and the second compression element 17 After the suction side communicates and the two-cylinder parallel one-stage compression operation is performed and the refrigerant exhibits a cooling action in the high-temperature evaporator 21, the refrigerant does not flow to the low-temperature evaporator 24 side, and the first compression element 16 and the second compression element 17 Therefore, the refrigerating room side (high temperature side) is rapidly cooled. At this time, even if the third on-off valve 30 is opened, the refrigerant is hardly flown to the low-temperature evaporator 24 side due to the resistance by the second expansion device 23, and the same effect can be obtained.
[0048]
Further, by opening the first on-off valve 28, the third on-off valve 30, and the fourth on-off valve 32 and closing the second on-off valve 29 and the fifth on-off valve 33, the first compression element 16 and the second compression element 17 are closed. The suction side communicates and a two-cylinder parallel one-stage compression operation is performed, and the refrigerant does not flow to the high temperature evaporator 21 side but flows to the first bypass passage 27, and its cooling capacity is reduced to low temperature evaporation on the freezer compartment side (low temperature side). Since it will be exhibited only in the container 24, it will be a rapid cooling operation on the freezer compartment side. At this time, when the second on-off valve 29 is opened, the refrigerant also flows to the high-temperature evaporator 21 side and can also cool the refrigerator compartment side.
[0049]
As described above, the refrigeration apparatus of the present embodiment is provided in the second bypass passage 31 and the second bypass passage 31 that connect the suction side of the first compression element 16 and the suction side of the second compression element 17. Since the fourth on-off valve 32 and the fifth on-off valve 33 provided between the first compression element 16 and the gas-liquid separator 22 are provided, cooling in the freezer compartment and the refrigerator compartment is performed. The temperature of each part in the storage can be made uniform in response to the load change, and further, it is possible to cope with a significant increase in the cooling load of the freezing room and the refrigerating room and to perform rapid cooling.
[0050]
【The invention's effect】
As described above, the invention according to claim 1 includes the first compression element, the second compression element, the condenser connected by piping together with the discharge side of the first compression element and the discharge side of the second compression element. A first expansion device piped to the outlet side of the condenser, a high temperature evaporator piped to the outlet side of the first expansion device, the high temperature evaporator and the suction side of the first compression element, A gas-liquid separator piped between, a second expansion device piped to the gas-liquid separator, and a low-temperature pipe piped between the second expansion device and the suction side of the second compression element An evaporator, the liquid refrigerant outlet side of the gas-liquid separator communicates with the second expansion device, and the gas refrigerant outlet side of the gas-liquid separator communicates with the first compression element. Therefore, the high-temperature circuit and the low-temperature circuit are formed as separate single-stage compression cycles. By operating at the proper pressure conditions as not to extremely low compression ratio such as a two-stage compression, it is possible to prevent the overall adiabatic efficiency. Therefore, the efficiency of the actual refrigeration cycle can be improved and the power consumption can be reduced.
[0051]
Furthermore, since it has a configuration comprising a first bypass passage communicating the inlet side and the outlet side of the high-temperature evaporator, and a first on-off valve provided in the first bypass passage, the refrigerator is further refrigerated. Either one of the chambers in different temperature zones, such as the freezer compartment or the refrigerator compartment of the device, can be properly cooled without refrigeration capacity becoming insufficient or excessive refrigeration capacity, and highly efficient power consumption Can be reduced.
[0052]
Furthermore, a second on-off valve provided between the branch point of the first bypass passage and the high-temperature evaporator, and a third on-off valve provided between the gas-liquid separator and the suction side of the second compression element Therefore, when defrosting the high-temperature evaporator or the low-temperature evaporator, cooling on only one side can be stopped to prevent an increase in the internal temperature.
[0053]
Furthermore, a second bypass passage communicating the suction side of the first compression element and the suction side of the second compression element, a fourth on-off valve provided in the second bypass passage, the first compression element and the gas-liquid Since it has a configuration with a fifth on-off valve provided between the separator, the temperature of each part in the refrigerator can be made uniform in response to changes in the cooling load in the freezer compartment and refrigerator compartment. Furthermore, it is possible to cope with a significant increase in the cooling load of the freezer compartment and the refrigerator compartment and to perform rapid cooling.
[Brief description of the drawings]
[Fig. 1] Refrigerant circuit diagram of Reference Example 1 of a refrigeration unit [Fig. 2] Pressure-enthalpy diagram of a refrigeration cycle in the refrigeration unit of the same reference example [Fig. 3] Refrigerant circuit diagram of Reference Example 2 of a refrigeration unit FIG. 4 is a refrigerant circuit diagram of the first embodiment of the refrigeration apparatus according to the present invention. FIG. 5 is a refrigerant circuit diagram of a conventional two-stage compression refrigeration cycle. FIG. Cross section of separator 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 16 1st compression element 17 2nd compression element 19 Condenser 20 1st expansion apparatus 21 High temperature evaporator 22 Gas-liquid separator 23 2nd expansion apparatus 24 Low temperature evaporator 25 Liquid refrigerant outlet 26 Gas refrigerant outlet 27 First bypass Passage 28 first on-off valve 29 second on-off valve 30 third on-off valve 31 second bypass passage 32 fourth on-off valve 33 fifth on-off valve

Claims (1)

A first compression element, a second compression element, a condenser piped together with the discharge side of the first compression element and the discharge side of the second compression element, and a first expansion piped to the outlet side of the condenser A high temperature evaporator piped to the outlet side of the first expansion device, a gas-liquid separator piped between the high temperature evaporator and the suction side of the first compression element, and the gas A liquid refrigerant of the gas-liquid separator, comprising: a second expansion device piped to the liquid separator; and a low-temperature evaporator piped between the second expansion device and the suction side of the second compression element. The outlet side communicates with the second expansion device, the gas refrigerant outlet side of the gas-liquid separator communicates with the first compression element, and the inlet side and outlet side of the high-temperature evaporator communicate with each other. A first bypass passage, a first on-off valve provided in the first bypass passage, and the first bypass passage. A second on-off valve provided between the branch point of the gas passage and the high-temperature evaporator; a third on-off valve provided between the gas-liquid separator and the suction side of the second compression element; A second bypass passage communicating the suction side of the first compression element and the suction side of the second compression element, a fourth on-off valve provided in the second bypass passage, the first compression element, and the A fifth on-off valve provided between the gas-liquid separator, closing at least the first on-off valve, and opening the second on-off valve, the fourth on-off valve, and the fifth on-off valve, Rapid cooling operation is performed in the high-temperature evaporator, and at least the fifth on-off valve is closed, and the first on-off valve, the third on-off valve, and the fourth on-off valve are opened to perform the rapid cooling operation in the low-temperature evaporator. A freezing and refrigeration apparatus characterized by that .

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