JPH09243185A - Refrigeration cycle operation method and refrigeration device using the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody a safe and economical refrigeration cycle by using a substitute refrigerant without any need to revalue from the view point of pressure resistance and safety strength. SOLUTION: Refrigeration devices 1, 2, 3, 4 and 5, which are set to economical pressure resistance and safety strength lower than required pressure resistance and safety strength against the pressure of refrigerants generated at a refrigerator cycle, are employed for this operation system. When a pressure sensor 11 detects that the pressure of refrigerants has reached economical pressure resistance and safety strength or before the pressure of refrigerants reaches the value, it is so arranged that a control means 12 may be changed over to low pressure operation mode at which the pressure of refrigerants is lowered at the refrigeration cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle operating method and a refrigerating apparatus using the same, and particularly to a refrigerating cycle operating method suitable for a refrigerating cycle using a non-azeotropic mixed refrigerant and a refrigerating apparatus using the same. It relates to the device.

[0002]

2. Description of the Related Art In recent years, following the regulation of CFC Freon which is a specific refrigerant, regulation of Freon HCFC which is a designated refrigerant is being accelerated. R22 which is the refrigerant of the air conditioner
Is no exception. Therefore, a substitute refrigerant for R22 has been desired, and various refrigerants have been developed. Various refrigerants that have the same capacity and COP as R22 and are excellent in safety have been proposed.

Among these alternative refrigerants, R407C, which is a mixed refrigerant of three kinds, was initially noted. However, it became clear that the performance and operability were slightly inferior to the initial estimate, which was said to have a pressure almost equal to that of R22, an equivalent capacity, and an equivalent COP, and instead, R410A emerged.

This refrigerant is a mixed refrigerant of R32 and R125, and the composition of R32 which is a low boiling point refrigerant is as large as about 50% as compared with R407C which has been noticed before, so that the pressure in the refrigeration cycle is R22. It turns out that it will be considerably higher than. JP-A-3-17058
No. 5 discloses that R32 is 60% by weight or less and R125 is 85% by weight.
Disclosed is a non-azeotropic mixed refrigerant containing R134a in an amount of 15% by weight or less and 15 to 80% by weight.

JP-A-3-158660 discloses that a compressor is connected to a condenser and further connected to an evaporator through one or a plurality of stages, a gas-liquid separator and a heat exchanger, in sequence. Disclosed is a multi-stage gas-liquid separation type refrigeration cycle in which a low temperature is generated by enclosing a boiling mixed refrigerant, which prevents an abnormal increase in the refrigerant pressure in the flow path related to the discharge side of the compressor.

[0006]

However, Japanese Patent Application Laid-Open No. Hei 3-1
In the one disclosed in Japanese Patent No. 58660, the non-azeotropic mixed refrigerant is
At the same time as the refrigerant that condenses at room temperature, a large amount of refrigerant that does not condense must be filled.Therefore, at the time of starting the cycle, the refrigeration cycle parts are not cooled, so the refrigerant exists in a gas state, especially at high pressure. It only prevents the abnormally high voltage rise.

Therefore, in view of the fact that the composition of the low boiling point refrigerant is large and the pressure in the refrigeration cycle becomes higher than that in the case of R22 even in normal operation, it is necessary to review all of the refrigeration cycle equipment from the viewpoint of pressure resistance and safety strength. However, it is also necessary to consider the legal relationship from the allowable pressure of the joint at the time of overload. Under these circumstances, specific development using such an alternative refrigerant has not been carried out so far so far, and a practical device has not been provided yet.

The present invention provides a refrigerating cycle operating method and a refrigerating apparatus using the same, which makes it possible to realize a refrigerating cycle safely and economically by using an alternative refrigerant without the need to review the pressure resistance and safety strength. The purpose is.

[0009]

A refrigeration cycle operating method according to the invention of claim 1 is a refrigeration apparatus set to an economic pressure-resistant safety strength lower than a pressure-resistant safety strength required for a pressure of a refrigerant generated in a refrigeration cycle. Is used to switch to a low-pressure operation mode in which the refrigerant pressure drops in the refrigeration cycle when or before the refrigerant pressure reaches the economic pressure resistance / safety strength.

The refrigerating apparatus according to the invention of claim 8 is provided with a refrigerating cycle device having an economic pressure resistance and safety strength lower than a pressure resistance and safety strength necessary for the pressure of the refrigerant generated in the refrigeration cycle, Detecting means for detecting predetermined data, and control means for switching to a low pressure operation mode in which the refrigerant pressure in the refrigeration cycle decreases before the detected value by the detecting means reaches a pressure state corresponding to the economic pressure resistance safety strength, or before reaching Is provided.

In the structure of the first or eighth aspect of the invention, the refrigeration cycle equipment of the refrigeration system is set to have an economical pressure-resistant safety strength lower than the pressure-resistant safety strength required for the pressure of the refrigerant generated in the refrigeration cycle. Therefore, the device becomes cheaper, and the refrigerant pressure reaches the pressure corresponding to the economic pressure resistance safety strength, or the refrigeration cycle switches to the low pressure operation mode in which the pressure of the refrigerant decreases before reaching the economical pressure. Since the refrigerant is not operated at a pressure higher than the safety strength against pressure, it is possible to ensure the safety of use.

Therefore, even if an alternative refrigerant having a large refrigerant pressure is used as in the invention of claim 7 or 15, it is possible to safely use the conventional inexpensive refrigerating equipment for R22 having a low refrigerant pressure as it is, It can be put to practical use immediately without the need to review refrigeration cycle equipment and laws and regulations from the pressure resistance and safety strength.

According to a second or ninth aspect of the invention, in addition to the first or eighth aspect of the invention, the drive of the compressor is set to a low rotation speed in the low pressure operation mode.

In the configuration of the invention of claim 2 or 9, in addition to the invention of claim 1 or 8, the compressor for pressurizing the refrigerant in the low pressure operation mode is made to have a low rotation speed, which is the pressure of the refrigerant. It is safe to reduce the pressure of the increased refrigerant quickly and accurately by directly affecting the low pressure operation mode.It is safe to set the low pressure operation mode near the time when the allowable pressure is full. The function deterioration of can be minimized. Moreover, since only the rotation speed of the existing compressor is controlled, no special equipment or cost is required. Further, since the compressor only rotates at a low speed, there is an advantage that it is difficult to notice the operation of the non-azeotropic mixed refrigerant countermeasure.

According to a third or tenth aspect of the present invention, in the first or eighth aspect of the invention, the opening degree of the expansion device provided between the condenser and the evaporator is set to be large in the low pressure operation mode.

In the structure of the third or tenth aspect of the present invention, the opening degree of the expansion device for decompressing and expanding the refrigerant discharged from the condenser is increased, and this directly affects the pressure of the refrigerant to increase the refrigerant. Since the pressure is quickly and accurately lowered, it is safe and the low pressure operation mode may be set at the time when the allowable pressure is full, and the deterioration of the function of the refrigeration cycle due to the low pressure operation mode can be minimized. Further, the refrigeration cycle in which the electric expansion device is adopted can be used as it is, and the device is not particularly complicated and the cost is not increased. Further, since only the opening of the expansion device is increased, there is an advantage that it is difficult to notice the operation mode as a countermeasure against the non-azeotropic mixed refrigerant.

According to the invention of claim 4 or 11, in addition to the invention of claim 1 or 8, the driving of the compressor is stopped in the low pressure operation mode.

In the structure of the invention of claim 4 or 11, the compressor for pressurizing the refrigerant in the low pressure operation mode is stopped, the pressurization of the refrigerant is immediately stopped, and the pressure of the increased refrigerant is immediately decreased. Therefore, it is safer, and the low-pressure operation mode may be set at the time when the allowable pressure is full, and the deterioration of the function of the refrigeration cycle due to the low-pressure operation mode can be suppressed to the minimum. Is better than

According to the invention of claim 5 or 12, in the invention of claim 1 or 8, the fan of the condenser is set to a high rotation speed in the low pressure operation mode.

According to the invention of claim 6 or 13, in the invention of claim 1 or 8, the fan of the evaporator is set to a low rotation speed in the low pressure operation mode.

In the structure of the present invention as defined in claim 5, 12, 6 or 13, the condenser fan is set to a high rotation speed or the evaporator fan is set to a low rotation speed in the low pressure operation mode. By promoting the condensation of the refrigerant in the cooler or suppressing the evaporation of the refrigerant in the evaporator, the pressure of the refrigerant is efficiently reduced, so it is safe and only controls the rotation speed of the existing fan. The conventional control function can be used as it is, and the device is not complicated and the cost is not increased. Moreover, since it is only necessary to increase or decrease the rotation speed of the fan, there is an advantage that it is difficult to notice the operation mode for coping with the non-azeotropic mixed refrigerant.

The invention of claim 14 is the invention of claims 8, 9, and 11.
In any one of the inventions 1 to 13, the control means further switches the drive frequency of the controlled device to switch to the low-pressure operation mode.

In such a structure, the eighth, ninth and eleventh aspects are provided.
In addition to the invention according to any one of 1 to 13, the control target device for the low voltage operation mode is further controlled by an inverter that switches the drive frequency by the control means, and the low voltage operation mode is executed. The low-pressure operation mode has the advantage that fine control is possible, and it is effective in common with the control means for normal operation of the refrigeration cycle.

[0024]

DETAILED DESCRIPTION OF THE INVENTION Several embodiments of the present invention will be described below with reference to FIGS.

(First Embodiment) FIG. 1 shows a refrigerating cycle of a refrigerating apparatus using a non-azeotropic mixed refrigerant, in which a compressor 1, a condenser 2, a throttle device 3 and an evaporator 4 are connected in an annular shape. And constitutes the main circuit of the refrigeration cycle. In reality, it may be a heat pump type having a four-way valve.

The non-azeotropic mixed refrigerant used for this is, for example, R
32 is a non-azeotropic mixed refrigerant composed of R125. The composition ratio of this non-azeotropic mixed refrigerant is such that R32 is 50% and R1 is
25 is 50%. However, the content of R32, which is a low-boiling-point refrigerant, needs to be equal to or more than a predetermined amount in order to secure a sufficient refrigeration cycle function, although not limited thereto. Therefore, when the refrigeration cycle is repeated, the pressure of the refrigerant becomes considerably higher than that of the conventional R22.

Now, when the conventional R22 is used, the pressure is P
1, the pressure P2 when using the non-azeotropic mixed refrigerant is
It is assumed that P2 = α · P1 (where α> 1). When the pressure resistance safety strength σ1 required for the conventional refrigeration cycle equipment is σ1 = S · P1 (where S is a safety coefficient), the refrigeration apparatus of the first embodiment using the non-azeotropic mixture refrigerant Pressure resistance and safety strength σ2 required for refrigeration cycle equipment is σ2
= S · P2 = S · α · P1. Therefore, the withstand pressure safety strength required in the first embodiment is α times or more that in the case of using the conventional R22. In the experiments conducted by the present inventors, the condensation temperature was 6
At 0 ° C., it is 26 Kg / cm ² when the conventional R22 is used, whereas it is 42 Kg / cm ² when the non-azeotropic mixed refrigerant of the first embodiment is used. Therefore, in this case α
≈1.62.

In order to satisfy this, in the first embodiment, the refrigeration cycle including the compressor 1, the condenser 2, the expansion device 3, the evaporator 4, the pipe 5 connecting them, and the joints of each part (not shown) and the like. It is necessary to review the equipment and the laws.

Since the first embodiment does not require this, the economic pressure resistance safety strength σ3 = S · S lower than the pressure resistance safety strength σ2 = S · P · 2 required for the pressure P2 of the refrigerant generated in the refrigeration cycle. The one equipped with the refrigeration cycle equipment set to P2 · D (however, D <1) is adopted. In addition to this, predetermined data regarding the pressure of the refrigerant, the first embodiment
Then, the pressure sensor 11 as a detection means for detecting the discharge pressure of the compressor 1 and the detection value by the pressure sensor 11 reach the pressure state P3 = P · D corresponding to the economic pressure resistance safety strength σ3 = S · P2 · D. Alternatively, the frequency commanding means 12 is provided as a control means for switching to the low pressure operation mode in which the refrigerant pressure in the refrigeration cycle decreases before reaching.

The frequency commanding means 12 works with the input value from the pressure sensor 11 or before the discharge pressure of the compressor 1 reaches P · D, and outputs a frequency command signal for switching the compressor 1 to a low rotation speed. Output to the compressor 1 so that the compressor 1 switches to a low rotation speed.

As described above, in the first embodiment, the compressor 1, the condenser 2, the expansion device 3, the evaporator 4 of the refrigeration system,
A pressure resistance and safety strength σ2 = S · P2 necessary for the pressure P2 of the refrigerant generated in the refrigerating cycle by various refrigerating cycle devices such as the pipe 5 connecting these and joints of not shown parts.
Economical pressure resistance and safety strength σ3 = S · P2 · D, which is lower than that, so the device becomes cheaper,
Low pressure in which the pressure of the refrigerant reaches the pressure P3 = P · D corresponding to the economic pressure resistance safety strength σ3 = S · P2 · D, or before the refrigerant pressure decreases due to the low rotation speed of the compressor 1 in the refrigeration cycle. Since the mode is switched to the operation mode, it is possible to ensure the safety of use without operating at a refrigerant pressure exceeding economic pressure resistance safety strength σ3 = S · P2 · D. Therefore,
Even if the above-mentioned alternative refrigerant, which increases the refrigerant pressure, is used, it is possible to safely use the conventional low-cost refrigeration equipment for R22, which has a low refrigerant pressure, as it is, and it is troublesome to review refrigeration cycle equipment and laws and regulations from the pressure resistance safety strength. It can be used immediately without the need. In the first embodiment, since α≈1.62, the economic pressure resistance and safety strength σ3 = S · P2 · D and the corresponding upper limit pressure P3 of the refrigerant P3 = P · D, the value of D is the reciprocal of α. It is possible to guarantee the safe use by setting 1 / 1.62≈0.62.

The economic design and the ensuring of safety as in the first embodiment are also effective when applied to a conventional refrigeration cycle using R22.

In particular, when the compressor 1 for pressurizing the refrigerant in the low pressure operation mode is set to a low rotational speed, this directly affects the pressure of the refrigerant, and the increased pressure of the refrigerant is quickly and accurately lowered, which is safer. The low-pressure operation mode may be set near the time when the allowable pressure is full, and the deterioration of the function of the refrigeration cycle due to the low-pressure operation mode can be minimized. Further, since only the rotation speed of the existing compressor 1 is controlled, no special equipment or cost is required. Further, since the compressor 1 only rotates at a low speed, there is an advantage that it is difficult to notice the operation of the non-azeotropic mixed refrigerant countermeasure.

Further, the frequency command means as in the first embodiment can share the control function of the control means for controlling the inverters of the fans of the compressor 1, the condenser 2 and the evaporator 4, and the refrigeration system. The main body control means such as a microcomputer provided for controlling the operation of the inverter can be used as it is, and the characteristic of the inverter control for finely controlling according to various modes and states is that the low-voltage operation in the first embodiment is performed. The same can be applied to the mode control.

The state in which the condenser 2 exchanges heat with the outdoor air to radiate heat and the evaporator 4 exchanges heat with the indoor air to absorb heat is the cooling operation, and the condenser 2 exchanges heat with the indoor air. The heating operation is a state in which heat is radiated and the evaporator 4 exchanges heat with the outdoor air to absorb heat. The first embodiment is effective in either case. Therefore, although not shown, a well-known four-way valve may be provided in the circuit of the refrigeration cycle to perform a heat pump type refrigeration cycle.

Further, in the first embodiment, it is essential to detect the use upper limit pressure P3 = P · D of the refrigerant. However, it is not necessary to detect this directly. In other words, it can be detected by monitoring the change in the rotation speed of the compressor 1 reflected by the pressure of the refrigerant and the change in the current driving the compressor 1.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention. In the second embodiment, as shown in FIG. 2, the pressure sensor 11 uses the refrigerant upper limit pressure P3 = P ·
When D is detected, the frequency 0 command means 21 operates, the drive frequency 0 is input to the compressor 1, the drive is stopped, and the mode is switched to the low pressure operation mode.
Is different from the case. The same members are designated by the same reference numerals, and overlapping description will be omitted.

In the second embodiment, the compressor 1 for pressurizing the refrigerant in the low pressure operation mode is stopped, the pressurization of the refrigerant is immediately stopped, and the pressure of the increased refrigerant is immediately decreased. It is safer than in the case of the first embodiment, and the low-pressure operation mode may be set at the time when the allowable pressure is full, and it is excellent in that the function deterioration of the refrigeration cycle due to the low-pressure operation mode can be suppressed to the minimum. .

(Third Embodiment) FIG. 3 shows the third embodiment. The third embodiment is different from the first and second embodiments in that the refrigeration cycle equipment is different in that the expansion device 3 is an electric one having an electric actuator 31 such as a solenoid as shown in FIG. When the sensor 11 detects the use upper limit pressure P3 = P · D of the refrigerant, the expansion valve opening adjustment command means 32 as a control means operates to increase the opening degree of the expansion device 3, so that the low-pressure operation is performed. The mode control is different from that of the first and second embodiments. Other configurations are the same as those of the first and second embodiments. The same members are denoted by the same reference numerals, and redundant description will be omitted.

In the third embodiment, when the pressure sensor 11 detects the use upper limit pressure P3 = P · D of the refrigerant, the opening degree of the expansion device 3 for decompressing and expanding the refrigerant discharged from the condenser 2 is increased. This directly affects the pressure of the refrigerant so that the pressure of the increased refrigerant can be quickly and accurately lowered, so it is safe and the low pressure operation mode can be set when the allowable pressure is full, and the low pressure operation mode can be set. It is possible to minimize the deterioration of the function of the refrigeration cycle. Further, the refrigeration cycle in which the electric expansion device 3 is adopted can be used as it is, and the device is not particularly complicated and the cost is not increased. Further, since the opening degree of the expansion device 3 is simply increased, there is an advantage that it is difficult to notice the operation mode of the non-azeotropic mixed refrigerant countermeasure.

(Fourth Embodiment) FIG. 4 shows a fourth embodiment of the present invention. In the fourth embodiment, as shown in FIG. 4, the indoor unit 45 and the outdoor unit 46 include a four-way valve 41.
In the case of a heat pump type refrigerating apparatus which is operated by switching the functions of the condenser and the evaporator by switching the above, the internal fan rotation speed increase command means 42 and the outer fan rotation speed increase command means 43 which are control means. In the inner fan rotation speed increase command means 42 and the outer fan rotation speed increase command means 43, the pressure sensor 11 uses the refrigerant upper limit pressure P3 = P.
-It works when D is detected and controls to increase the rotation speed of the condenser fan. In conjunction with the switching between the cooling state shown by the solid line of the four-way valve 41 and the heating state shown by the broken line, the external fan rotation speed increasing command means 43 operates during cooling, and the fan 46a of the outdoor unit 46 serving as a condenser. , The inner fan rotation speed increase command means 42 operates during heating,
The number of rotations of the fan 45a of the indoor unit 45 serving as a condenser is increased. For this switching control, the output of the pressure sensor 11 is interlocked with the switching of cooling and heating by the four-way valve 41, and a detection signal is input to the external fan rotation speed increasing command means 43 during cooling, and heating is performed. At this time, the detection signal is input to the inner fan rotation speed increasing command means 42. However, when the inner fan rotation speed increasing instruction means 42 and the outer fan rotation speed increasing instruction means 43 constitute one control means such as an internal function of the microcomputer, the switch 47 is for changing the mode of this control means. It can be replaced with the control function of the control means, which is called an internal function.

As in the fourth embodiment, the pressure sensor 11
In the low-pressure operation mode in which the refrigerant use upper limit pressure P3 = P · D is detected, when the fan of the condenser is set to a high rotation speed, the condensation of the refrigerant in the condenser is promoted, and the refrigerant pressure is efficiently increased. Since it is reduced, it is safe and only controls the rotation speed of the existing fan, so that the conventional control function can be used as it is in the same manner as in the first embodiment, the device becomes complicated, and the cost increases. There is nothing to do. Moreover, since the number of rotations of the fan is only increased, there is an advantage that it is difficult to notice the operation mode for the non-azeotropic mixed refrigerant.

Even in a refrigerating apparatus having a refrigerating cycle that is not a heat pump type, it is possible to control the number of rotations of the condenser fan in the same manner to exhibit the same function and effect, which also belongs to the category of the present invention.

(Fifth Embodiment) FIG. 5 shows a fifth embodiment of the present invention. In the fifth embodiment, as shown in FIG. 5, the indoor unit 45 and the outdoor unit 46 include a four-way valve 41.
In the case of a heat pump type refrigerating device which is operated by switching the functions of the condenser and the evaporator by switching the above, the inner fan rotation speed reduction command means 52 and the outer fan rotation speed reduction command means 53 which are control means. In the inner fan rotation speed reduction command means 52 and the outer fan rotation speed reduction command means 53, the pressure sensor 11 uses the refrigerant upper limit pressure P3 = P.
-It works when D is detected and controls to lower the rotation speed of the evaporator fan. In conjunction with switching between the cooling state shown by the solid line of the four-way valve 41 and the heating state shown by the broken line, the internal fan rotation speed reduction command means 52 operates during cooling, and the fan 45a of the indoor unit 45 serving as an evaporator. Lowering the number of rotations of the fan, and the external fan number-of-rotations lowering command means 53 operates during heating,
The rotation speed of the fan 46a of the outdoor unit 46 serving as an evaporator is reduced. For this switching control, the output of the pressure sensor 11 is interlocked with the switching of heating and cooling by the four-way valve 41, and a detection signal is input to the internal fan rotation speed reduction command means 52 during cooling, and heating is performed. At this time, the detection signal is input to the external fan rotation speed reduction command means 53.

As in the fifth embodiment, the pressure sensor 11
If the fan speed of the evaporator is set to a low rotation speed in the low-pressure operation mode in which the refrigerant has used the upper limit pressure P3 = P · D, the evaporation of the refrigerant in the evaporator is suppressed, and the pressure of the refrigerant is efficiently reduced. Since it is safe and only controls the rotation speed of the existing fan, the conventional control function can be used as it is in the same manner as in the first embodiment, and the device becomes complicated and the cost increases. There is no such thing. Moreover, since it is only necessary to increase or decrease the rotation speed of the fan, there is an advantage that it is difficult to notice the operation mode for coping with the non-azeotropic mixed refrigerant.

Even in a refrigerating apparatus having a refrigerating cycle that is not a heat pump type, the rotational speed of the fan of the evaporator can be controlled in the same manner, and the same operational effect can be exhibited, which also belongs to the category of the present invention.

Further, various controls in the low pressure operation modes of the first to fifth embodiments can be used by being combined in various ways as needed, and the speed and effect of reducing the pressure of the refrigerant can be enhanced.

Although the pressure sensor has been used as the detecting means for detecting the predetermined data relating to the pressure of the refrigerant, other pressure detecting means may be used, and in some cases, the number of revolutions of the compressor that reflects the pressure. Alternatively, the drive current of the compressor may be detected to replace the pressure detection.

[0049]

According to the invention of claim 1 or 8, the economical pressure resistance and safety strength is set lower than the pressure of the refrigerant generated by the refrigeration cycle equipment, and the apparatus becomes cheaper and the refrigerant is economical. Ensure the safety of use because it will not operate at a low pressure operation mode where the pressure of the refrigerant drops before reaching or reaches the pressure corresponding to the pressure resistance safety strength, and the refrigerant pressure will not exceed the economic pressure resistance safety strength. be able to. Therefore, even when an alternative refrigerant having a large refrigerant pressure is used as in the invention of claim 7 or 15, it can be safely used as it is as a conventional inexpensive refrigerating device for R22 having a low refrigerant pressure, and the pressure resistance safety strength is high. Therefore, it can be put to practical use immediately without the need to review refrigeration cycle equipment and laws.

According to the invention of claim 2 or 9, in addition to the invention of claim 1 or claim 8, further lowering the number of revolutions of the compressor directly affects the pressure of the refrigerant to increase the pressure. Since the pressure of the refrigerant drops quickly and accurately, it is safe, and the low-pressure operation mode may be set near the time when the allowable pressure is full, and the functional deterioration of the refrigeration cycle due to the low-pressure operation mode can be minimized. Moreover, since only the rotation speed of the existing compressor is controlled, no special equipment or cost is required. Further, since the compressor only rotates at a low speed, there is an advantage that it is difficult to notice the operation of the non-azeotropic mixed refrigerant countermeasure.

According to the invention of claim 3 or 10, increasing the opening degree of the expansion device directly affects the pressure of the refrigerant, and the increased pressure of the refrigerant is quickly and accurately reduced, which is safe. The low pressure operation mode may be set at the time when the allowable pressure is full, and the deterioration of the function of the refrigeration cycle due to the low pressure operation mode can be minimized. Further, the refrigeration cycle in which the electric expansion device is adopted can be used as it is, and the device is not particularly complicated and the cost is not increased. Further, since only the opening of the expansion device is increased, there is an advantage that it is difficult to notice the operation mode as a countermeasure against the non-azeotropic mixed refrigerant.

According to the invention of claim 4 or 11, by stopping the compressor for pressurizing the refrigerant, the pressurization of the refrigerant is immediately stopped and the increased pressure of the refrigerant is immediately decreased, so that the safety is further improved. Therefore, the low pressure operation mode may be set at the time when the allowable pressure is full, and the deterioration of the refrigeration cycle function due to the low pressure operation mode can be minimized.
It is superior to the invention of claim 2 or 9.

According to the invention of claim 5, 12, 6 or 13, in the low pressure operation mode, the fan of the condenser is set to a high rotation speed, or the fan of the evaporator is set to a low rotation speed, and the refrigerant in the condenser is changed. It is safe because the pressure of the refrigerant is efficiently reduced by promoting the condensation of the refrigerant or suppressing the evaporation of the refrigerant in the evaporator, and it is only necessary to control the rotation speed of the existing fan. Can be used as it is, and the device does not become complicated and the cost does not increase. Moreover, since it is only necessary to increase or decrease the rotation speed of the fan, there is an advantage that it is difficult to notice the operation mode for coping with the non-azeotropic mixed refrigerant.

According to the invention of claim 14, claim 8,
In addition to the invention of any one of 9, 11 to 13,
Since the low-voltage operation mode is executed by the inverter control in which the drive frequency of the control-target device for the low-voltage operation mode is switched by the control means, there is an advantage that the operation of the control-target device can be finely controlled for the low-voltage operation mode. , Is effective in common with the control means for normal operation of the refrigeration cycle.

[Brief description of drawings]

FIG. 1 is a main circuit configuration diagram showing a refrigerating apparatus according to a first embodiment of the present invention.

FIG. 2 is a main circuit configuration diagram showing a refrigeration system according to a second embodiment of the present invention.

FIG. 3 is a main circuit configuration diagram showing a refrigerating apparatus according to a third embodiment of the present invention.

FIG. 4 is a main circuit configuration diagram showing a refrigerating apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a main circuit configuration diagram showing a refrigerating apparatus according to a fifth embodiment of the present invention.

[Explanation of symbols]

 1 Compressor 2 Condenser 3 Throttle device 4 Evaporator 11 Pressure sensor 12 Frequency command means 21 Frequency 0 command means 31 Electric actuator 32 Expansion valve opening adjustment command means 41 Four-way valve 42 Inner fan speed increase command means 43 Outer fan rotation Number increase command means 45 Indoor unit 45a Indoor fan 46 Outdoor unit 46a Outdoor fan 47 Changeover switch 52 Inner fan rotation speed reduction command means 53 Outer fan rotation speed reduction command means

Front Page Continuation (72) Inventor Akira Fujitaka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yukio Watanabe 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Invention Yoshinori Kobayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yuichi Yakumaru Kadoma City, Osaka Prefecture 1006 Kadoma Matsushita Electric Industrial Co., Ltd. (72) Inventor Yamaguchi Adult Kadoma City, Osaka Prefecture 1006 Kadoma Matsushita Electric Industrial Co., Ltd. (72) Inventor Toshio Wakabayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (15)

[Claims] 1. When a refrigerant pressure reaches economic economical pressure safety strength by using a refrigerating device which is set to economic pressure safety strength lower than necessary pressure safety strength against pressure of refrigerant generated in refrigeration cycle, A method for operating a refrigeration cycle, characterized by switching to a low-pressure operation mode in which the refrigerant pressure in the refrigeration cycle decreases before reaching the limit. 2. The refrigeration cycle operating method according to claim 1, wherein in the low-pressure operation mode, the drive of the compressor is set to a low rotation speed. 3. The refrigeration cycle operating method according to claim 1, wherein in the low-pressure operation mode, the opening degree of the expansion device provided between the condenser and the evaporator is set to be large. 4. The refrigeration cycle operating method according to claim 1, wherein in the low pressure operation mode, driving of the compressor is stopped. 5. The refrigeration cycle operating method according to claim 1, wherein in the low pressure operation mode, the fan of the condenser is set to a high rotation speed. 6. The refrigeration cycle operating method according to claim 1, wherein in the low pressure operation mode, the fan of the evaporator is set to a low rotation speed. 7. The non-azeotropic mixed refrigerant is used as the refrigerant.
7. The refrigerating cycle operating method according to any one of 6 to 6. 8. A detection means for detecting predetermined data relating to the pressure of the refrigerant, comprising a refrigeration cycle device set to an economical pressure-resistant safety strength lower than a pressure-resistant safety strength required for the pressure of the refrigerant generated in the refrigeration cycle. And a control means for switching to a low pressure operation mode in which the refrigerant pressure in the refrigeration cycle decreases before the value detected by the detection means reaches a pressure state corresponding to the economic pressure resistance safety strength, or before reaching. Refrigeration equipment. 9. The refrigerating apparatus according to claim 8, wherein the control means sets the drive of the compressor to a low rotation speed. 10. The refrigerating apparatus according to claim 8, wherein the control means sets a large opening degree of the expansion device provided between the condenser and the evaporator. 11. The refrigerating apparatus according to claim 8, wherein the control means stops driving of the compressor. 12. The refrigerating apparatus according to claim 8, wherein the control means sets the fan of the condenser to a high rotation speed. 13. The refrigerating apparatus according to claim 8, wherein the control means sets the fan of the evaporator to a low rotation speed. 14. The control means switches the drive frequency of the controlled device to switch to the low pressure operation mode.
The refrigeration apparatus according to any one of 9, 11 to 13. 15. The refrigerant is a non-azeotropic mixed refrigerant.
The refrigerating apparatus according to any one of to 14.