JPH10176865A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle device having a superior safety characteristic as well as a superior retention of environment in which refrigerant having a high pressure, for example, HFC refrigerant can be used without requiring any high anti-pressure of a refrigeration cycle equipment while a safety characteristic of the refrigeration cycle equipment is assured. SOLUTION: In a freezing cycle in which a compressor 1, an outdoor heat exchanger 2, a capillary tube 3 and an indoor heat exchanger 4 are connected in sequence by piping to cause refrigerant to be circulated, a bypass pipe 5 is connected between a high pressure pipe and a low pressure pipe. This bypass pipe 5 is provided with a high pressure release valve 6 acting as a pressure relief device. The high pressure release valve 6 is opened when a high pressure side pressure Pd is abnormally increased to become a value more than a designed pressure value set in view of safety (defined by the Freezer Safety Regulation Related Rules) on the basis of a capacity of the refrigeration cycle and an applied refrigerant and then the bypass pipe 5 is made to be communicated. With such a communication as above, the abnormal increasing in the high pressure side pressure Pd is restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle device used for an air conditioner or the like.

[0002]

2. Description of the Related Art R-12 refrigerant, R-22 refrigerant and the like are generally used in an air conditioner. These refrigerants contain chlorine and have a problem of depletion of the ozone layer.
The ozone depletion coefficient is “1.0” for R-12 refrigerant and R-22 for R-22 refrigerant.
The refrigerant is “0.055”. As a refrigerant having an ozone depletion potential of zero, there is an HFC (fluorocarbon containing hydrogen element) refrigerant.

[0003]

An HFC refrigerant having an ozone depletion potential of zero has a considerably higher pressure than refrigerants conventionally used. For this reason, in actual use, it is necessary to increase the pressure resistance of the refrigeration cycle equipment.

[0004] However, there is a problem that increasing the pressure resistance of the refrigeration cycle equipment leads to an increase in cost. The present invention has been made in consideration of the above circumstances, and has as its object the purpose of eliminating the need for increasing the pressure resistance of refrigeration cycle equipment and ensuring the safety of refrigeration cycle equipment, while using a high-pressure refrigerant such as HFC refrigerant. An object of the present invention is to provide a refrigeration cycle apparatus which is usable and has excellent safety and environmental preservation properties.

[0005]

A refrigeration cycle apparatus according to the present invention comprises a refrigeration cycle in which a refrigerant is circulated by connecting a compressor, a condenser, a decompressor, and an evaporator, and a high-pressure side of the refrigeration cycle. A bypass connected between the low-pressure side, and a pressure relief device provided at the bypass, operating at a pressure higher than a design pressure value set for safety based on the capacity of the refrigeration cycle and the refrigerant used, It has.

The refrigeration cycle apparatus according to the second aspect of the present invention uses an HFC refrigerant as the refrigerant in the first aspect. The refrigeration cycle apparatus according to a third aspect of the present invention uses a high-pressure release valve that opens when the pressure becomes higher than a design pressure value as the pressure relief device according to the first aspect.

According to a fourth aspect of the present invention, there is provided a refrigeration cycle apparatus according to the first aspect, wherein an on-off valve is used as a pressure relief device, and pressure detecting means for detecting a high pressure side of the refrigeration cycle is provided. Control means for opening the on-off valve when the pressure is equal to or higher than a predetermined value is provided. A refrigeration cycle apparatus according to a fifth aspect of the present invention is the refrigeration cycle apparatus according to any one of the first to fourth aspects, further comprising an alarm unit for issuing an alarm when the pressure relief device operates.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, an outdoor heat exchanger (condenser) 2 is connected to a discharge port of a compressor 1 by piping, and an indoor heat exchanger (evaporator) is connected to the outdoor heat exchanger 2 via a decompressor, for example, a capillary tube 3. ) 4 is connected by piping. Further, the suction port of the compressor 1 is connected to the indoor heat exchanger 4 by piping. Thereby, a refrigeration cycle is configured.

A design pressure value (high-pressure-side rated pressure) set from the viewpoint of safety (defined by the standards related to refrigeration security regulations) based on the capacity of the refrigeration cycle and the refrigerant used.
For example, 2.94 MPa is selected.

One end of a bypass pipe 5 is connected to a high pressure side pipe between the discharge port of the compressor 1 and the outdoor heat exchanger 2, and the other end of the bypass pipe 5 is connected to the indoor heat exchanger 4 and the suction of the compressor 1. Connect to the low pressure side piping between the port. Then, a high-pressure release valve 6 is provided in the bypass pipe 5 as a pressure relief device.

The high-pressure release valve 6 is, as shown in FIG.
It has an inflow side pipe 11 connected to the high pressure side pipe, and an outflow side pipe 12 connected to the low pressure side pipe. A valve seat 13 is provided in a flow path between the two pipes. A movable valve element 14 is provided, a spring 16 is connected to the valve element 14 via a rod 15, and a housing space for the spring 16 is partitioned by a bellows 17.

The biasing force of the spring 16 acts in a direction to press the valve body 14 against the valve seat 13, and the high pressure side pressure Pd
Is smaller than the predetermined value Pda, the valve body 14 is brought into contact with the valve seat 13 against it, and when the high-pressure side pressure Pd becomes higher than the predetermined value Pda, the valve body 14 is separated from the valve seat 13 without being able to resist it. Let it.

The predetermined value Pda is a pressure slightly higher than the above-mentioned design pressure value of 2.94 MPa for safety of the refrigeration cycle.
3.0MPa is selected. An outdoor fan 7 is provided for the outdoor heat exchanger 2, and an indoor fan 8 is provided for the indoor heat exchanger 4.

The operation will be described. In normal stable operation, the high-pressure side pressure Pd of the refrigeration cycle is 2.94M
On the lower side than Pa, the high-pressure release valve 6 is closed and the bypass pipe 5 is shut off.

The high-pressure side pressure Pd abnormally rises for some reason, such as overload operation or unnecessary operation continuation of the compressor 1 due to welding of a switch contact, and the high-pressure side pressure Pd increases to a design pressure value of 2.94 MPa. When the pressure exceeds the predetermined value Pda, the high-pressure release valve 6 is opened and the bypass pipe 5 is turned on. Due to this conduction, part of the refrigerant flowing through the high-pressure side pipe flows to the low-pressure side through the bypass pipe 5, and an abnormal rise in the high-pressure side pressure Pd is suppressed.

The design pressure value is 2.94MPa and the high pressure release valve 6
FIG. 3 shows the relationship of the predetermined value Pda (= 3.0 MPa), which is the operating point of. Therefore, HFC-32 (difluoroethane), HFC-125 (pentafluoroethane), HFC
-134a (tetrafluoroethane) or other single refrigerant, or R-410A refrigerant (HF
50% by weight of C-32 and 50% by weight of HFC-125), R-4
07C refrigerant (HFC-32, HFC-125 and HFC-134a
Even if an HFC refrigerant having an ozone depletion coefficient of zero and a high pressure is used, the safety of the refrigeration cycle equipment can be ensured without having to increase the pressure resistance of the refrigeration cycle equipment.

Since it is not necessary to increase the pressure resistance of the refrigeration cycle equipment, there is no increase in cost. In addition, since an HFC refrigerant having an ozone depletion potential of zero can be used, it is excellent in environmental conservation.

(2) A second embodiment will be described. FIG.
As shown in (1), one end of the bypass pipe 5 is connected to the liquid side pipe between the outdoor heat exchanger 2 and the capillary tube 3.

The other structure is the same as that of the first embodiment. The liquid-side pipe between the outdoor heat exchanger 2 and the capillary tube 3 is also on the high-pressure side. When the high-pressure side pressure Pd rises abnormally, the high-pressure release valve 6 opens, the bypass pipe 6 conducts, and the high-pressure side pressure Pd becomes abnormal. The rise is suppressed.

(3) A third embodiment will be described. FIG.
As shown in (1), one end of the bypass pipe 5 is connected to the liquid-side pipe between the outdoor heat exchanger 2 and the capillary tube 3, and the capillary tube 9 is connected to the low-pressure side (downstream side) of the bypass pipe 6 as a throttle device. Insert.

The other structure is the same as that of the first embodiment. According to this configuration, when the high-pressure side pressure Pd rises abnormally and the high-pressure release valve 6 is opened, the capillary tube 9 becomes a flow path resistance, and the difference between the high-pressure side pressure Pd and the low-pressure side pressure Ps decreases at once. prevent. As a result, it is possible to prevent a situation in which the liquid refrigerant flows into the low-pressure side at once, and it is possible to avoid liquid compression of the compressor 1.

It is of course possible to insert and connect the capillary tube 9 to the bypass pipe 5 of the first embodiment shown in FIG. (4) A fourth embodiment will be described.

As shown in FIG. 6, as a pressure relief device,
An electromagnetic on-off valve 20 is provided instead of the high-pressure release valve 6. Further, a high-pressure sensor 21 is attached to the high-pressure side pipe between the discharge port of the compressor 1 and the outdoor heat exchanger 2 as pressure detecting means,
The heat exchanger temperature sensor 22 is attached to the outdoor heat exchanger 2.
The high pressure sensor 21 detects the high pressure side pressure Pd. The heat exchanger temperature sensor 22 detects the temperature (condenser temperature) Tc of the outdoor heat exchanger 2.

The discharge port of the compressor 1 and the outdoor heat exchanger 2
The high-pressure switch 10 is attached to the high-pressure side pipe between them.
The high pressure switch 10 has a high pressure side pressure Pd of a design pressure value of 2.94.
When it reaches MPa, it opens.

FIG. 7 shows the control circuit. Commercial AC power supply 30
To the controller 40 via the high-voltage switch 10. The controller 40 is connected with a remote control type operating device (referred to as a remote controller) 41, the high-pressure sensor 21, the heat exchanger temperature sensor 22, and the relays 42, 43, 44, and 45. The remote controller 41 is for setting various operating conditions, and includes an alarm lamp 50 attached thereto.

An electromagnetic switch 46 is connected to the power supply 30 via the high voltage switch 10 and the relay contact 42a. The indoor fan motor 8M is connected to the power supply 30 via the high voltage switch 10 and the relay contact 43a.

The outdoor fan motor 7M is connected to the power supply 30 via the high voltage switch 10 and the relay contact 44a. The power supply 30 includes a high voltage switch 10 and a relay contact 4
The solenoid on-off valve 20 is connected via 5a.

The compressor motor 1M is connected to the power supply 30 via a switch contact 46a. A current sensor 47 is attached to a current path between the compressor motor 1M and the switch contact 46a,
The output terminal of the current sensor 47 is connected to the control unit 40.

The control section 40 has a main function means that the pressure Pd detected by the pressure sensor 21 during operation is a predetermined value Pda (= 3.
When the pressure reaches 0 MPa), control means is provided for turning on (energizing) the relay 45 to open the on-off valve 20.

Next, the operation of the above configuration will be described with reference to the flowchart of FIG. When the operation is turned on by the remote controller 41 (YES in step 101), the relay 4
2, 43 and 44 are turned on (step 102). With this relay on, the electromagnetic switch 46, the indoor fan motor 8M,
The outdoor fan motor 7M operates, and the compressor motor 1
M operates.

The pressure Pd detected by the pressure sensor 21 and a predetermined value P
da (= 3.0MPa) (Step 103), and the detected pressure P
If d is less than the predetermined value Pda (NO in step 103), the operation is continued.

During operation, for example, if the outdoor fan motor 7M fails and does not operate, the ventilation to the outdoor heat exchanger 2 is stopped, and the high-pressure side pressure Pd may rise abnormally.
In this case, when the high-pressure side pressure Pd reaches the design pressure value of 2.94 MPa, the high-pressure switch 10 is operated and opened, and all operations are stopped. Thus, the abnormal increase of the high pressure Pd is suppressed, and the refrigeration cycle equipment is protected.

However, if the high-pressure switch 10 fails and does not open, the abnormal increase in the high-pressure side pressure Pd cannot be suppressed, and the high-pressure side pressure Pd increases beyond the design pressure value of 2.94 MPa.

The pressure detected by the pressure sensor 21 (high pressure side pressure)
When Pd reaches a predetermined value Pda (YES in step 103),
The relay 45 is turned on (step 104). Further, the alarm lamp 50 of the remote controller 41 is turned on (step 105).
).

When the relay 45 is turned on, the on-off valve 20 opens, and the bypass pipe 5 is turned on. Due to this conduction, part of the refrigerant flowing through the high-pressure side pipe flows to the low-pressure side through the bypass pipe 5, and an abnormal rise in the high-pressure side pressure Pd is suppressed.

The design pressure value 2.94 MPa, which is the operating point of the high pressure switch 10, and the predetermined value Pda (= the operating point of the on-off valve 20)
3.0MPa) is shown in FIG. Further, an alarm lamp 50 is lit, and by this lighting, the high pressure side pressure Pd
Is abnormally raised and the control for the suppression has been notified.

Thereafter, the detected pressure Pd of the pressure sensor 21 is compared with 2.5 MPa lower than the predetermined value Pda (step 106).
If the detected pressure Pd falls below 2.5 MPa (YES in step 106), the relay 45 is turned off (step 107).
). Thereby, the bypass pipe 5 is shut off. However, the alarm lamp 50 remains lit.

When the operation of turning off the remote controller 41 is performed (YES in step 108), all the relays are turned off (step 109). As a result, the operation stops. In this way, even when the high-pressure switch 10 fails, the bypass pipe 5 is turned on when the detected pressure Pd of the pressure sensor 21 reaches the predetermined value Pda, and the high-pressure side pressure Pd is reduced, so that the refrigeration cycle equipment can be reliably operated. Can be protected.

In particular, even if the refrigeration cycle is filled with an HFC refrigerant having an ozone depletion potential of zero and a high pressure, the safety of the refrigeration cycle equipment can be ensured without having to increase the pressure resistance of the refrigeration cycle equipment.

Since it is not necessary to increase the pressure resistance of the refrigeration cycle equipment, the cost does not increase. In addition, since an HFC refrigerant having an ozone depletion potential of zero can be used, it is excellent in environmental conservation.

(5) A fifth embodiment will be described. The control unit 40 turns on (energizes) the relay 45 when the detected temperature (condenser temperature) Tc of the heat exchanger temperature sensor 22 rises and reaches a set value of 73 ° C. during operation, and opens and closes the relay. Control means for opening the valve 20.

The other structure is the same as that of the fourth embodiment. That is, as shown in parentheses in FIG.
When the detected temperature (condenser temperature) Tc reaches the set value 73 ° C. (YES in step 103), the relay 45 is turned on (step 104). When the relay 45 is turned on, the on-off valve 2
0 opens to make the bypass pipe 5 conductive, thereby suppressing an abnormal rise in the high-pressure side pressure Pd.

The set value 73 ° C., as shown in FIG. 3, corresponds to the evaporator temperature when the high-pressure side pressure Pd reaches a predetermined value Pda. Thereafter, the detected temperature Tc of the heat exchanger temperature sensor 22
Is lower than 52 ° C., the relay 45 is turned off (step 107), and the bypass pipe 5 is shut off.

The effect is the same as in the fourth embodiment. (6) A sixth embodiment will be described. The control unit 40 turns on (energizes) the relay 45 when the detection current (compressor operation current) I of the current sensor 47 increases to reach 105% of the normal value during operation, and opens and closes the on-off valve. And control means for opening 20.

The other structure is the same as that of the fourth embodiment. That is, as shown in parentheses in FIG. 8, when the detection current I of the current sensor 47 reaches 105% of the normal value (YES in step 103).
), The relay 45 is turned on (step 104). When the relay 45 is turned on, the on-off valve 20 is opened to make the bypass pipe 5 conductive, thereby suppressing an abnormal increase in the high-pressure side pressure Pd.

As shown in FIG. 3, 105% of the normal value corresponds to the operating current I when the high-pressure side pressure Pd reaches a value higher than the design pressure value 2.94 MPa (for example, 3.1 MPa). Thereafter, when the detection current I of the current sensor 47 falls below 75% of the normal value, the relay 45 is turned off (step 107) and the bypass pipe 5 is cut off.

The effect is the same as that of the fourth embodiment. (7) A seventh embodiment will be described. As shown in FIG. 9, the control unit 40 is connected to the power supply 3 without using the high-voltage switch 10.
Connect directly to 0. Further, a series circuit of the relay contact 45a and the on-off valve 20 is not connected through the high-voltage switch 10,
Connect directly to power supply 30.

The other structure is the same as in the fourth, fifth and sixth embodiments. According to such a configuration, even when the high-pressure switch 10 is opened when the high-pressure side pressure Pd rises abnormally, the control operation of the control unit 40 and the operation of the on-off valve 20 can be executed.

Therefore, even if the switch contact 46a is welded due to aging and the operation of the compressor 1 continues unnecessarily, the on-off valve 20 is reliably operated when the high-pressure side pressure Pd rises abnormally. By opening, the bypass pipe 5 can be made conductive.

(8) In the above embodiments, the refrigeration cycle dedicated to cooling is described as an example. However, the present invention can be similarly applied to a heat pump refrigeration cycle capable of cooling and heating.

In the fourth to seventh embodiments, the operation of the compressor 1 may be interrupted simultaneously with the opening operation of the on-off valve 20 when the high pressure Pd abnormally rises. In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

[0052]

As described above, according to the present invention, a bypass is connected between the high-pressure side and the low-pressure side of the refrigeration cycle, and the bypass is connected to the bypass at a pressure higher than the safety design pressure value of the refrigeration cycle. Since a working pressure relief device is provided,
To provide a refrigeration cycle device that is excellent in safety and environmental preservation that enables the use of a high-pressure refrigerant, for example, HFC refrigerant, without having to increase the pressure resistance of the refrigeration cycle device and ensuring the safety of the refrigeration cycle device. it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a refrigeration cycle of a first embodiment.

FIG. 2 is a cross-sectional view illustrating a configuration of a high-pressure release valve according to the first embodiment.

FIG. 3 is a diagram showing a relationship between a high pressure side pressure Pd, an operating point of a high pressure release valve, a condenser temperature, and a compressor operating current in each embodiment.

FIG. 4 is a diagram illustrating a configuration of a refrigeration cycle according to a second embodiment.

FIG. 5 is a diagram showing a configuration of a refrigeration cycle according to a third embodiment.

FIG. 6 is a diagram showing a configuration of a refrigeration cycle according to fourth, fifth, sixth, and seventh embodiments.

FIG. 7 is a diagram illustrating a configuration of a control circuit according to fourth, fifth, and sixth embodiments.

FIG. 8 is a flowchart for explaining the operation of the fourth, fifth, sixth, and seventh embodiments.

FIG. 9 is a diagram illustrating a configuration of a control circuit according to a seventh embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Outdoor heat exchanger (condenser), 3 ... Capillary tube (decompressor), 4 ... Indoor heat exchanger (evaporator), 5 ... Bypass pipe, 6 ... High pressure release valve (pressure relief device) ), 10: high pressure switch, 20: solenoid on-off valve, 21
... pressure sensor, 22 ... heat exchanger temperature sensor, 30 ... commercial AC power supply, 40 ... control unit, 41 ... remote control, 42, 4
3, 44, 45: relay, 46: electromagnetic switch, 47: current sensor, 50: alarm lamp.

Claims (5)

[Claims] 1. A refrigeration cycle that connects a compressor, a condenser, a decompressor, and an evaporator to circulate a refrigerant, a bypass connected between a high-pressure side and a low-pressure side of the refrigeration cycle, And a pressure relief device that operates at a pressure higher than a design pressure value set for safety based on the capacity of the refrigeration cycle and the refrigerant used. 2. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant is an HFC refrigerant. 3. The refrigeration cycle apparatus according to claim 1, wherein the pressure relief device is a high-pressure release valve that opens when the pressure becomes higher than a design pressure value. 4. The refrigeration cycle apparatus according to claim 1, wherein the pressure relief device is an on-off valve, and a pressure detection unit for detecting a high pressure side pressure of the refrigeration cycle, and a pressure detected by the pressure detection unit is a predetermined value. Control means for opening the on-off valve when the value is equal to or greater than a value. 5. The refrigeration cycle apparatus according to claim 1, further comprising alarm means for issuing an alarm when the pressure relief device operates.