JP3213433B2 - Refrigeration cycle equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle apparatus such as an air conditioner using a non-azeotropic mixed refrigerant, and more particularly to a refrigeration cycle apparatus provided with a detecting means for surely detecting a leak of the mixed refrigerant. .

[0002]

2. Description of the Related Art In a conventional refrigeration cycle device such as an air conditioner, Freon R22 is frequently used as a refrigerant. In recent years, it has been said that Freon R22 has a problem with respect to the environment. Various alternative refrigerants that are harmless even if they leak into the external environment have been proposed.
One is a non-azeotropic mixed refrigerant obtained by mixing a plurality of refrigerants having different boiling points.

[0003]

However, if such a non-azeotropic mixed refrigerant is used as it is in a conventional refrigeration cycle device such as an air conditioner, if this mixed refrigerant leaks to the outside, Since the composition of the refrigerant mixture changes, the evaporator freezes due to a decrease in the refrigerating capacity and a decrease in the evaporation temperature.

Therefore, if it is suspected that a part of the mixed refrigerant has leaked, all of the mixed refrigerant enclosed in the refrigeration cycle is discharged once, and the mixed refrigerant is newly discharged again. There is a problem that it is necessary to re-encapsulate, which increases the cost and is very complicated.

[0005] Further, even when the refrigerating capacity is reduced due to a cause other than the leakage of the refrigerant or the like, a case where the mixed refrigerant is re-entered as a refrigerant leak is also assumed.

Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to provide a refrigeration cycle apparatus capable of reliably detecting a leak of a mixed refrigerant.

[0007]

The present invention is configured as follows to solve the above-mentioned problems.

That is, the present invention provides a closed refrigeration system in which at least a compressor, a condenser, a decompression device, and an evaporator are connected by a refrigerant pipe to circulate a non-azeotropic mixed refrigerant obtained by mixing a plurality of refrigerants having different boiling points. A cycle, a discharge temperature sensor provided in a refrigerant pipe connecting the compressor and the condenser for detecting a refrigerant temperature, and a low boiling point of the non-azeotropic mixed refrigerant provided in the refrigerant pipe connecting the compressor and the condenser. A refrigerant concentration sensor for detecting the composition ratio of the refrigerant, and the refrigerant mixture when the composition ratio of the low-boiling refrigerant detected by the refrigerant concentration sensor corresponding to the predetermined refrigerant temperature detected by the discharge temperature sensor falls below a predetermined value. And a control means for displaying the leak or stopping the operation of the refrigeration cycle.

[0009]

If a part of the mixed refrigerant leaks from the refrigeration cycle, for example, the low-boiling refrigerant in the mixed refrigerant leaks more than the other refrigerants, so that the composition ratio of the low-boiling refrigerant in the mixed refrigerant fluctuates. . The change in the composition ratio of the low boiling point refrigerant is detected by a refrigerant concentration sensor, and a detection signal is provided to the control unit. At this time, the control means is also provided with a discharge temperature detection signal of the mixed refrigerant in the gas phase from the discharge temperature sensor. For this reason, the control means determines whether or not the composition ratio of the low-boiling refrigerant at the predetermined value of the discharge temperature has dropped below the predetermined value. The leak is displayed to notify the user that the leak of the mixed refrigerant has occurred, and the operation of the refrigeration cycle is stopped.

Therefore, according to the present invention, when a change in the composition ratio of the low-boiling-point refrigerant in the non-azeotropic mixed refrigerant is detected, the leak of the refrigerant is not immediately indicated, but the gas-phase state on the refrigerant discharge side is detected. At a predetermined temperature of the discharged refrigerant at
Since the leak of the non-azeotropic mixed refrigerant is detected when it is detected that the composition ratio has dropped below the predetermined value, it is possible to improve the leak detection accuracy of the non-azeotropic mixed refrigerant.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a refrigeration cycle diagram of an embodiment in which the present invention is applied to an air conditioner. In the drawing, an air conditioner 1 is a compressor driven by an inverter (not shown) so as to be able to control the rotation speed. 2, a four-way valve 3, an indoor heat exchanger 5 having an indoor fan 4, an expansion valve 6 which is a decompression device, and an outdoor heat exchanger 8 having an outdoor fan 7 are sequentially and annularly arranged in this order by a refrigerant pipe 9. The refrigeration cycle is connected to reversibly circulate the non-azeotropic mixed refrigerant.

The non-azeotropic refrigerant mixture is formed by mixing a plurality of refrigerants having different boiling points, for example, R1 as a high-boiling refrigerant A1
25 and R32 as the low-boiling-point refrigerant A2.

The refrigeration cycle is operated by switching the four-way valve 3 to circulate the mixed refrigerant in the direction indicated by the solid line arrow in the drawing, and is operated by heating, and is circulated in the direction indicated by the broken line in the drawing to perform cooling operation.

A room temperature sensor 10 for detecting a room temperature and an indoor heat exchange temperature sensor 11 for detecting the temperature of the indoor heat exchanger 5 are provided in an indoor cabinet (not shown) containing the indoor heat exchanger 5 and the like. And these two sensors 10,
11 is electrically connected to an indoor controller 12 composed of a microprocessor or the like by a signal line shown by a broken line in the figure.

As shown in FIG. 2, the indoor controller 12 controls the room temperature detected by the room temperature sensor 10 and the room heat exchange temperature sensor 1.
1 and a set temperature set by a remote controller or the like are read, and an operation command frequency signal or the like necessary for controlling the room temperature to the set temperature is supplied to the outdoor controller 13. .

On the other hand, the discharge pipe 9a of the compressor 2 has a discharge temperature sensor 14 for detecting the discharge temperature of the mixed refrigerant, and the concentration of one of the low-boiling refrigerants A2 in the mixed refrigerant, that is, the refrigerant concentration for detecting the composition ratio. A sensor 15 is provided.

These sensors 14 and 15 are electrically connected to an outdoor controller 13 composed of a microprocessor or the like by signal lines shown by broken lines in the figure.

FIG. 3 is a curve showing the relative relationship between the temperature and the composition of the non-azeotropic mixed refrigerant at a constant pressure. The vertical axis represents the refrigerant temperature T. The horizontal axis indicates the composition ratio X2 of the low-boiling-point refrigerant A2. Therefore, for example, when the mixing ratio of the high-boiling refrigerant A1 and the low-boiling refrigerant A2 is 1: 1, the composition ratio X2 of the low-boiling refrigerant A2 is 0.5, so when the pressure is Pi and the temperature T is Ti, The composition ratio of the low-boiling refrigerant A2 in the gas phase is, for example, Xi. Here, the pressure Pi is a normal pressure with no leakage of the mixed refrigerant, and the pressure Pi0 indicates a pressure when a leakage of the mixed refrigerant occurs.

Therefore, in a normal state with no refrigerant leakage, the refrigerant concentration sensor 15 detects the composition ratio Xi. Further, the outdoor controller 13 stores in advance the range of the refrigerant concentration in the case where the refrigerant is normally charged at each refrigerant temperature T.

However, if the mixed refrigerant leaks now, particularly the low-boiling refrigerant A2 leaks in large quantities, so that the composition ratio of the low-boiling refrigerant A2 in the mixed refrigerant becomes small. For example, assume that the composition ratio X2 of the low-boiling-point refrigerant A2 has decreased from 0.5 to 0.3. In this case, the pressure also drops from Pi to Pi0, and the composition curve becomes as shown by the broken line in the figure.

When the refrigerant temperature T is Ti, the composition of the gaseous low-boiling-point refrigerant A2 decreases from Xi to Xi0, which is smaller than Xi. That is, the range of the normal state where there is no refrigerant leak is, for example, (Xi−α) <Xi <(Xi +
α), Xi0 <(Xi−α), and the state is abnormal. When this state is detected by the outdoor controller 13 via the refrigerant concentration sensor 15, the outdoor refrigerant leak indicator lamp 16 is turned on as shown in FIG. 2, and a refrigerant leak signal is output as a kind of operation stop state information signal. The control signal is supplied to the controller 12 to turn on the indoor refrigerant leak display lamp 17 to display the leak of the mixed refrigerant. When the outdoor controller 13 detects a refrigerant leak, the outdoor controller 13 gives an operation stop signal to the compressor 2 to stop the operation.

Accordingly, when the change in the composition ratio of the mixed refrigerant is detected by the refrigerant concentration sensor 15 during the operation of the air conditioner 1, it can be reliably detected as a leakage of the mixed refrigerant.

When a leak of the mixed refrigerant is detected,
The indoor / outdoor controllers 12 and 13 light the refrigerant leak display lamps 16 and 17 both inside and outside to display the refrigerant leakage and stop the operation of the compressor 2, the indoor and outside fans 4 and 7, and the like. Then, the occurrence of the refrigerant leak is notified.

In the above embodiment, the case where the present invention is applied to an air conditioner has been described. However, the present invention is not limited to this, but is generally applied to a refrigeration cycle apparatus.

In the above embodiment, high and low boiling point refrigerants (A1: R125, A2: R32) are used as non-azeotropic refrigerant mixtures.
Has been described, but the present invention is not limited to this, and can be widely applied to a mixture of a plurality of refrigerants having different boiling points.

[0027]

As described above, according to the present invention, when the non-azeotropic refrigerant mixture leaks, the change in the composition ratio of the low-boiling refrigerant which leaks more than other refrigerants can be reduced by connecting the compressor and the condenser. The leak of the non-azeotropic mixed refrigerant can be detected with high accuracy and reliability by detecting the refrigerant in accordance with the predetermined refrigerant temperature in the gas phase state in the refrigerant pipe. In addition, by displaying the leak of the non-azeotropic mixed refrigerant or stopping the operation of the refrigeration cycle, the leak of the non-azeotropic mixed refrigerant can be notified to a user or the like.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of an embodiment of a refrigeration cycle apparatus according to the present invention.

FIG. 2 is a block diagram of a control system shown in FIG.

FIG. 3 is a view showing a composition curve of a non-azeotropic mixed refrigerant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Compressor 3 Four-way valve 4 Indoor fan 5 Indoor heat exchanger 6 Expansion valve 7 Outdoor fan 8 Outdoor heat exchanger 9 Refrigerant piping 9a Discharge piping 10 Room temperature sensor 11 Indoor heat exchange temperature sensor 12 Indoor controller 13 outdoor controller 14 discharge temperature sensor 15 refrigerant concentration sensor 16 outdoor refrigerant leak indicator lamp 17 indoor refrigerant leak indicator lamp

Continuation of front page (56) References JP-A-59-129366 (JP, A) JP-A-3-160277 (JP, A) JP-A-6-101911 (JP, A) JP-A-6-101912 (JP, A) , A) JP-A-6-117737 (JP, A) JP-A-6-265245 (JP, A) JP-A-54-81793 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB Name) F25B 49/02 520 F25B 1/00 395 F25B 13/00

Claims (1)

(57) [Claims] At least a compressor, a condenser, a decompression device,
A closed refrigeration cycle in which an evaporator is connected by a refrigerant pipe to circulate a non-azeotropic mixed refrigerant obtained by mixing a plurality of refrigerants having different boiling points, and a refrigerant provided in a refrigerant pipe connecting the compressor and a condenser. A discharge temperature sensor for detecting a temperature, a refrigerant concentration sensor provided in a refrigerant pipe connecting the compressor and the condenser for detecting a composition ratio of a low-boiling refrigerant of the non-azeotropic mixed refrigerant, and the discharge temperature sensor for detecting When the composition ratio of the low-boiling-point refrigerant detected by the refrigerant concentration sensor corresponding to the predetermined refrigerant temperature falls to a predetermined value or less, a leak of the mixed refrigerant is displayed, or control means for stopping the operation of the refrigeration cycle, A refrigeration cycle device comprising: