JP3601122B2 - Refrigeration equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigerating apparatus having an accumulator type refrigerating cycle using a non-azeotropic mixed refrigerant.
[0002]
[Prior art]
In recent years, a refrigeration cycle using two or three types of non-azeotropic mixed refrigerants containing no chlorine atom has been proposed in order to comply with the restriction on the use of CFCs (see Japanese Patent Application Laid-Open No. 62-94768).
[0003]
[Problems to be solved by the invention]
However, when a non-azeotropic mixed refrigerant is used, there is a problem that the refrigerant composition circulating in the refrigeration cycle and the sealing composition are different due to the characteristic that the liquid phase composition and the gas phase composition are different in the two-phase region. For example, when a non-azeotropic mixed refrigerant is used in an accumulator-type refrigeration cycle that accumulates excess refrigerant in an accumulator, a high-boiling refrigerant component is included in the composition of the liquid refrigerant that accumulates in the accumulator because the dryness of the refrigerant flowing into the accumulator is large. As a result, the operating pressure increases and the coefficient of performance (COP) decreases. Thus, in a refrigeration cycle using a non-azeotropic mixed refrigerant, it is difficult to ensure stable performance and reliability because the circulating composition greatly changes with respect to the enclosed composition of the mixed refrigerant.
The present invention has been made based on the above circumstances, and an object thereof is to improve the performance and reliability of a cycle by suppressing the fluctuation of the circulation composition with respect to the composition of the non-azeotropic refrigerant mixture. Is to provide.
[0004]
[Means for Solving the Problems]
The present invention has the following features to attain the object mentioned above.
(Claim 1)
An accumulator-type refrigeration cycle using a non-azeotropic mixed refrigerant, a vibrator attached to the accumulator and configured to atomize liquid refrigerant that has accumulated inside the accumulator, and according to an operation state of the refrigeration cycle. A control device for controlling the operation of the shaker, wherein the control device performs a cycle operation in a state where the operation of the shaker is stopped during a necessary cool down of the refrigerating capacity, During steady operation in which efficiency is emphasized, the vibrator is operated to atomize the liquid refrigerant (liquid refrigerant having a high boiling point refrigerant component) accumulated in the accumulator .
[0006]
【The invention's effect】
(Claim 1)
In the accumulator type refrigeration cycle, since the composition of the liquid refrigerant accumulated in the accumulator has a high boiling point refrigerant component, the liquid refrigerant retained in the accumulator is atomized by a vibrator to facilitate evaporation, thereby refrigeration. Fluctuation in the composition of the refrigerant circulating in the cycle can be suppressed. As a result, the performance and reliability of the refrigeration cycle can be improved.
Further, by controlling the operation of the vibrator by the control device, the composition of the refrigerant circulating in the refrigeration cycle can be changed according to the operation state of the refrigeration cycle. For example, when the vibrator is not operated, more high-boiling refrigerant stays in the accumulator than low-boiling refrigerant. As a result, since most of the refrigerant composition circulating in the refrigeration cycle is a low-boiling-point refrigerant, a cycle operation that emphasizes capacity can be performed. In addition, when the high-boiling refrigerant accumulated in the accumulator is atomized by operating the exciter, the composition of the refrigerant circulating in the refrigeration cycle becomes close to the composition at the time of the filling (the high-boiling refrigerant is higher than when the exciter is not operated). Since the number of components increases), it is possible to perform a cycle operation that emphasizes efficiency.
[0008]
【Example】
Next, an embodiment of the refrigeration apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is an overall schematic diagram of an accumulator type refrigeration cycle.
The refrigerating apparatus of the present embodiment is applied to, for example, an air conditioner for an automobile, and includes an accumulator type refrigerating cycle 1 using two types of mixed refrigerants (for example, HFC32 and HFC134a) having no azeotropic point, and the refrigerating cycle. Atomizing means (to be described later) for atomizing the liquid refrigerant accumulated in the accumulator 2 according to the operating state of the accumulator 2.
The refrigeration cycle 1 is composed of the functional components of a compressor 3, an oil separator 4, a condenser 5, an expansion valve 6, an evaporator 7, and the accumulator 2, and is connected in a ring by a refrigerant pipe 8 as shown in FIG. ing.
[0009]
The atomizing means includes, as shown in FIG. 2, a vibrator 9 attached to the bottom surface of the accumulator 2 (or may be inside the accumulator 2) and a control device 10 for controlling the operation of the vibrator 9. .
The vibrator 9 has, for example, a built-in ultrasonic vibrator, and when energized via the control device 10, the ultrasonic vibrator vibrates to atomize the liquid refrigerant accumulated in the accumulator 2. it can.
The control device 10 controls the energization of the vibrator 9 according to the operation state of the refrigeration cycle 1 (for example, the temperature of the air cooled by the evaporator 7).
[0010]
Next, the operation of the present embodiment will be described.
The gas refrigerant discharged from the compressor 3 is supplied to the condenser 5 via the oil separator 4, and is condensed and liquefied by heat exchange with the air blown to the condenser 5 when flowing through the refrigerant passage of the condenser 5. On the other hand, the oil discharged from the compressor 3 together with the gas refrigerant is separated from the gas refrigerant by the oil separator 4, accumulated in the oil separator 4, and returned to the compressor 3 through the oil return pipe 11.
The refrigerant liquefied by the condenser 5 is decompressed and expanded by the expansion valve 6 and supplied to the evaporator 7. The low-temperature and low-pressure refrigerant supplied to the evaporator 7 evaporates by heat exchange with the air blown into the vehicle compartment when flowing through the refrigerant passage of the evaporator 7.
The refrigerant (gas-liquid two-phase state) evaporated by the evaporator 7 is separated into gas and liquid by the accumulator 2, the liquid refrigerant is accumulated in the accumulator 2, and the gas refrigerant is sucked by the compressor 3.
[0011]
Here, when a non-azeotropic mixed refrigerant is used as the refrigerant of the refrigeration cycle 1, if the low-boiling refrigerant component increases in the refrigerant composition circulating in the refrigeration cycle 1, the cycle efficiency (coefficient of performance COP) decreases, Ability improves. On the other hand, when the high-boiling-point refrigerant component increases in the refrigerant composition circulating in the refrigeration cycle 1, the refrigeration capacity slightly decreases, but the cycle efficiency improves (see FIG. 3).
Therefore, when a large refrigeration capacity is required at the time of cool down (rapid cooling) or the like, the low-boiling-point refrigerant component in the refrigerant composition circulating in the refrigeration cycle 1 is increased, and the cycle efficiency is emphasized during the steady operation. In this case, it is desirable to increase the number of high-boiling refrigerant components in the refrigerant composition circulating in the refrigeration cycle 1.
[0012]
On the other hand, in the refrigeration cycle 1 of the present embodiment, the liquid refrigerant accumulated in the accumulator 2 during the normal cycle operation has a composition having a large amount of high-boiling-point refrigerant components. In other words, it can be said that the ratio of the low-boiling-point refrigerant component increases (the state shown by composition (1) in FIG. 3). Therefore, at the time of cooling down which requires the refrigerating capacity, by performing the cycle operation with the vibrator 9 turned off, the liquid refrigerant having a high boiling point refrigerant component is accumulated in the accumulator 2 and the refrigerant circulating through the refrigeration cycle 1 is reduced. A composition having a high boiling point refrigerant component can be obtained. On the other hand, at the time of steady operation in which the cycle efficiency is emphasized, the vibrator 9 is turned off by atomizing the liquid refrigerant (liquid refrigerant having a high boiling point refrigerant component) accumulated in the accumulator 2 by turning on the vibrator 9. A refrigerant composition having a higher boiling point refrigerant component than in the case of (a state shown by composition (2) in FIG. 3) can be obtained. In addition, when the cycle is stopped, the exciter 9 is turned off, so that the refrigerant in the cycle mainly lays on the low-pressure side mainly around the high-boiling-point refrigerant (accumulates), so that the refrigerant composition in the cycle returns to the initial state. Return.
[0013]
(Effects of the present embodiment)
In the present embodiment, the refrigeration cycle 1 is circulated by turning on the vibrator 9 by the control device 10 and atomizing the liquid refrigerant having a high boiling point refrigerant component accumulated in the accumulator 2 to facilitate evaporation. Fluctuation in refrigerant composition can be suppressed. Thereby, the circulating composition of the refrigerant can be made closer to the refrigerant composition at the time of charging, so that the performance and reliability of the refrigeration cycle 1 can be improved.
In addition, by simply controlling the operation of the vibrator 9 in accordance with the operation state of the refrigeration cycle 1, it is possible to perform the cycle operation focusing on the capacity at the time of cooling down when the refrigeration capacity is required, and the cycle operation focusing on the efficiency at the time of the steady operation. Can be performed.
[0014]
In the initial stage of the cool down, if the high pressure of the refrigeration cycle 1 rises excessively because the refrigerant circulating in the refrigeration cycle 1 has a composition with a lot of low boiling point refrigerant components, the vibrator 9 is turned on and the refrigeration cycle 1 is turned on. By setting the refrigerant circulating through the refrigerant to have a composition having a high boiling point refrigerant component, the high pressure of the refrigeration cycle 1 can be reduced.
Further, in the case of performing the cycle operation in which the performance is emphasized by turning off the vibrator 9, a low-pressure pipe (from the discharge side of the expansion valve 6 to the suction side of the compressor 3) is used to accumulate more high-boiling-point refrigerant in the accumulator 2. It is also effective to make the refrigerant pipe 8) connecting between them into contact with the bottom of the accumulator 2.
[Brief description of the drawings]
FIG. 1 is an overall schematic diagram of a refrigeration cycle.
FIG. 2 is a cross-sectional view of an accumulator showing an attached state of an ultrasonic transducer.
FIG. 3 is a graph showing a relationship between a refrigerant composition ratio, a coefficient of performance ratio, and a cooling capacity ratio.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Accumulator 9 Exciter (atomization means)
10 control device (atomization means)

Claims (1)

An accumulator-type refrigeration cycle using a non-azeotropic mixed refrigerant,
A vibrator attached to the accumulator, for atomizing the liquid refrigerant retained inside the accumulator ,
A control device for controlling the operation of the vibrator according to the operating state of the refrigeration cycle,
The control device performs a cycle operation in a state where the operation of the vibrator is stopped at the time of a cool-down required for the refrigeration capacity, and operates the vibrator during the steady operation in which cycle efficiency is emphasized, thereby operating the accumulator to perform the cycle operation. A refrigeration apparatus for atomizing liquid refrigerant (liquid refrigerant having a high boiling point refrigerant component) accumulated in a tank .

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