JP2010127531A - Refrigeration air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigeration air conditioner preventing the excessive rise of high pressure and the lowering of low pressure during overload operation, and preventing the shortage of a refrigerant during normal operation. <P>SOLUTION: The refrigeration air conditioner 100 has a compressor 1, a condenser 2, a plurality of capillary tubes 3, an evaporator 4 equipped with heat transfer tubes of the same number as that of the capillary tubes 3, and a main circuit 101 forming a refrigerating cycle connecting them to circulate the refrigerant. The air conditioner also has a bypass circuit 6 making branch points 12 communicate with each other provided between the condenser 2 and the capillary tubes 3 with a junction 13 provided between the evaporator 4 and the compressor 1. A bypass electromagnetically operated valve 7, a bypass receiver 8, a bypass decompressing means 9 are sequentially installed in the bypass circuit 6. In a controller 10, when the pressure of a delivered refrigerant of the compressor 1 measured by a pressure sensor 11 reaches control upper limit pressure P1, the bypass electromagnetically operated valve 7 is opened, the refrigerants are sent into the capillary tubes 3 and the bypass circuit 6, and the high pressure is lowered. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration air conditioner, and more particularly, to a refrigeration air conditioner provided with a plurality of capillaries used both for decompression and distribution.

  Conventionally, as a refrigeration air conditioner, there are a compressor, an outdoor heat exchanger, a plurality of capillaries that combine decompression and distribution, an indoor heat exchanger that includes a heat transfer tube that communicates with each of the capillaries, and an accumulator. An invention is disclosed that includes a refrigerant circuit connected in order, reduces the number of capillaries used by opening and closing the solenoid valve, tightens the throttle, and adjusts the low pressure to avoid liquid return to the compressor (for example, , See Patent Document 1).

  In addition, a main circuit constituting the refrigeration cycle and a sub circuit including a refrigerant regulator are provided. When the refrigerant amount in the main circuit becomes excessive, surplus refrigerant is caused to flow into the sub circuit by opening and closing the solenoid valve, and the refrigerant regulator is An invention for reducing heat loss by storing is disclosed (for example, see Patent Document 2).

JP-A-4-372421 (page 2, FIG. 1) JP 2008-185295 A (page 6-7, FIG. 1)

However, the invention disclosed in Patent Document 1 has the following problems.
(A) Since a capillary tube is used for the pressure reducing means, the amount of restriction cannot be adjusted. That is, reliability is ensured by setting the throttle amount so that the liquid does not return to the compressor during low-load operation. The low load operation is a state in which the cooling operation is performed, for example, at an outside air temperature of 20 ° C., an indoor dry bulb temperature of 20 ° C., and a wet bulb temperature of 14 ° C., and is an environmental condition in which liquid is easily returned to the compressor. Therefore, on the contrary, during overload operation, the throttle becomes tight and the high pressure rises excessively.

  (Ii) On the other hand, in order to avoid an excessive increase in high pressure during overload operation, if the initial refrigerant charging amount is made small, the refrigerant becomes insufficient during normal operation, which also deteriorates performance (operation efficiency).

  (U) In addition, in order to carry out highly efficient operation during normal operation, all the capillaries are used to make the entire evaporator function. During overload operation such as when the outside air temperature rises, it is necessary to loosen the throttle to avoid a high pressure rise, but the number of capillaries used cannot be increased. Therefore, it is conceivable to perform a normal operation with additional capillaries on the upstream side of a plurality of conventional capillaries, and to bypass the additional capillaries with an electromagnetic valve during overload operation. However, during normal operation, distribution is performed in a gas-liquid two-phase state, resulting in performance deterioration due to poor distribution.

Furthermore, the invention disclosed in Patent Document 2 has the following problems.
(E) When applied to a refrigeration air conditioner equipped with a plurality of capillaries that combine decompression and distribution, and when the high pressure is excessive, the refrigerant is stored in the sub-circuit to suppress the high pressure. When stored, the low pressure also decreases and the suction superheat increases, so the discharge temperature rises excessively.

  (O) When the refrigerant is stored in the sub-circuit until the high pressure can be suppressed, the degree of supercooling may not be ensured at the condenser outlet. At this time, it flows into a plurality of capillaries that use both decompression and distribution in a gas-liquid two-phase state, resulting in performance deterioration due to poor distribution.

  The present invention has been made to solve the above-described problems, and prevents an excessive increase in high pressure and a decrease in low pressure during overload operation, and also prevents a refrigerant shortage during normal operation, And a refrigerating and air-conditioning apparatus that prevents a refrigerant from flowing into a plurality of capillaries that also serve as distribution in a gas-liquid two-phase state.

A refrigerating and air-conditioning apparatus according to the present invention includes a compressor that compresses and discharges a refrigerant, a condenser that condenses the refrigerant discharged from the compressor, and a decompression unit that depressurizes the refrigerant flowing out of the condenser, An evaporator for evaporating the refrigerant depressurized by the depressurizing means, and a main circuit for sequentially circulating the refrigerant by connecting them,
A bypass circuit that communicates a branch point provided between the condenser of the main circuit and the decompression means and a junction point provided between the evaporator and the compressor of the main circuit; Have
The decompression means comprises a plurality of capillaries,
The evaporator includes a heat transfer tube communicating with each of the capillaries,
In the bypass circuit, a bypass solenoid valve and a bypass pressure reducing means for decompressing the refrigerant are sequentially installed from the branch point toward the junction.
The main circuit is provided with a pressure sensor for measuring the pressure of the refrigerant discharged from the compressor,
And a control device that inputs a pressure value measured by the pressure sensor and controls opening and closing of the bypass solenoid valve according to the pressure value.

  Since the refrigerating and air-conditioning apparatus of the present invention has a bypass circuit, even when the refrigerant amount is filled up so that the operation efficiency during normal operation is maximized, the refrigerant circuit enters the bypass circuit during overload operation such as when the outside air temperature rises. It becomes possible to store the refrigerant and avoid an excessive increase in high pressure. As a result, high-efficiency operation is possible during normal operation, and reliability during overload operation can also be ensured.

[Embodiment 1]
1 to 3 illustrate a refrigeration air-conditioning apparatus according to Embodiment 1 of the present invention. FIG. 1 is a refrigerant circuit diagram showing a configuration, FIG. 2 is a refrigerant circuit diagram showing a refrigerant flow, and FIG. It is a figure which shows the effect | action of a control apparatus. In the following description and drawings, the same or corresponding parts are denoted by the same reference numerals, and a part of the description is omitted.

(Main circuit)
In FIG. 1, the refrigerating and air-conditioning apparatus 100 includes an outdoor unit 18 and an indoor unit 19. The outdoor unit 18 includes a compressor 1 that compresses and discharges the refrigerant, and a condenser 2 that condenses the refrigerant discharged from the compressor 1, while the indoor unit 19 includes a condenser 2 from the condenser 2. There are disposed decompression means 3 (formed by a plurality of capillaries, hereinafter referred to as “capillaries 3”) and an evaporator 4 for evaporating the refrigerant decompressed by the capillaries 3 for decompressing the refrigerant flowing out. . And these are connected sequentially and the main circuit 101 which performs the refrigerating cycle which a refrigerant | coolant circulates is formed.
The capillary tube 3 serves both as a pressure reducing action of the refrigerant and a distributing action to each heat transfer pipe of the evaporator. For this reason, in order to perform reliable pressure reduction and distribution in the capillary 3, it is necessary to allow the refrigerant to flow in a liquid state. The inflow in the gas-liquid two-phase state decreases the flow rate of the capillary 3 or causes a distribution failure, so that the operation efficiency decreases. The number of capillaries 3 is the same as the number of heat transfer tubes forming the evaporator 4.

(Bypass circuit)
In addition, a bypass circuit 6 (more precisely, a bypass) that connects a branch point 12 provided downstream of the condenser 2 of the main circuit 101 and a junction 13 provided downstream of the evaporator 4 of the main circuit 101. A circuit 6 is formed by the circuit 6 and a part of the main circuit 101).
The bypass circuit 6 includes a bypass solenoid valve 7 that switches between passage and shutoff of the refrigerant sequentially from the branch point 12 to the junction point 13, a bypass receiver 8 that stores the refrigerant, and a bypass pressure reducing unit that adjusts the flow rate of the refrigerant. 9 are installed.
Further, a pressure sensor 11 for measuring the pressure of the refrigerant discharged from the compressor 1 is installed on the outlet side of the compressor 1 of the main circuit 101, and the pressure value measured by the pressure sensor 11 is input. A control device 10 that controls opening and closing of the bypass electromagnetic valve 7 according to the value is installed.

(Refrigerant flow during normal operation)
Next, the flow of the refrigerant during normal operation of the refrigeration air conditioner 100 will be described. The normal operation is, for example, a state in which the cooling operation is performed at an outside air temperature of 33 ° C., an indoor dry bulb temperature of 28 ° C., and a wet bulb temperature of 23 ° C., and is the most common environmental condition.
In FIG. 2A, the bypass solenoid valve 7 is shut off during normal operation, and the refrigerant is not passed through the bypass circuit 6. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed and liquefied by the condenser 2, then distributed by the capillary 3, and further reduced in pressure to become a two-phase refrigerant. Then, after being evaporated and gasified by the evaporator 4, a refrigeration cycle is formed which is sucked into the compressor 1 and circulated, and the refrigerant circulates.
At this time, since the inside of the bypass circuit 6 is connected to the main circuit 101 at the junction 13 (same as the suction side of the compressor 1), it is maintained at a low pressure.

(Refrigerant flow during overload operation)
Next, the refrigerant flow during overload operation of the refrigeration air conditioner 100 will be described. The normal operation is a state in which the cooling operation is performed, for example, at an outdoor air temperature of 45 ° C., an indoor dry bulb temperature of 35 ° C., and a wet bulb temperature of 28 ° C., and is an environmental condition in which the outdoor air temperature is high and high pressure is likely to increase.
In (b) of FIG. 2, during overload operation, the bypass solenoid valve 7 is opened, and the refrigerant flows through the bypass circuit 6. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed and liquefied by the condenser 2, and then branched into a refrigerant flowing to the bypass circuit 6 and a refrigerant flowing to the capillary 3 at the branch point 12.

The refrigerant flowing into the capillary tube 3 is distributed by the capillary tube 3 as in the normal operation, further reduced in pressure to become a two-phase refrigerant, and evaporated by the evaporator 4.
On the other hand, since the bypass circuit 6 is maintained at a low pressure, the refrigerant can be bypassed promptly at the branch point 12. Since the flow rate of the refrigerant flowing into the bypass circuit 6 is limited by the bypass pressure reducing means 9, the refrigerant can be stored in the bypass circuit 6 (mainly, the bypass receiver 8).

When the refrigerant is stored in a separate circuit such as the bypass circuit 6, the amount of refrigerant in the high-pressure side circuit decreases and the pressure decreases. With this effect, it is possible to avoid an excessive increase in high pressure during overload operation, and to ensure reliability.
At the same time, the amount of refrigerant on the low pressure side decreases, and the low pressure decreases.
Furthermore, since the amount of refrigerant in the evaporator 4 is also reduced, heat exchange in the gas refrigerant state occupies most of the evaporator 4 and the suction superheat degree of the compressor 1 increases. For this reason, although the discharge temperature of the compressor 1 is excessively increased and reliability is lost, in the refrigeration air conditioner 100, the refrigerant branched to the bypass circuit 6 and flowing through the bypass pressure reducing means 9 is evaporated in the evaporator 4. Merges with gasified refrigerant. Since the refrigerant flowing through the bypass decompression means 9 is a two-phase refrigerant having a low dryness, when it is combined with the refrigerant gasified by the evaporator 4, the suction superheat degree of the compressor 1 is lowered and the discharge temperature is excessively increased. The rise can be prevented.

  The bypass pressure reducing means 9 adjusts the flow rate of the refrigerant flowing into the suction portion of the compressor 1 when the refrigerant is stored in the bypass circuit 6 and the high pressure is suppressed during the overload operation. The flow resistance of the bypass pressure reducing means 9 is such that the refrigerant sucked into the compressor 1 can maintain a gas state when the refrigerant is stored in the bypass circuit 6 and the high pressure is suppressed during overload operation. The refrigerant flow rate is set so that the suction superheat degree of 1 is 5 ° C. or higher or the discharge superheat degree is 20 ° C. or higher.

  As described above, the refrigerating and air-conditioning apparatus 100 is provided with the capillary 3 that can avoid liquid return to the compressor 1 during low-load operation, and encloses the amount of refrigerant that maximizes operating efficiency during normal operation. A bypass circuit 6 that prevents an excessive increase in high pressure during overload operation is installed to enable high-efficiency operation while ensuring reliability.

(Control of bypass solenoid valve)
In the refrigerating and air-conditioning apparatus 100, a pressure sensor 11 that measures the pressure of refrigerant discharged from the compressor 1 is installed, and the opening and closing of the bypass electromagnetic valve 7 is controlled by the pressure measured by the pressure sensor 11.
In FIG. 3, the vertical axis represents pressure, and the horizontal axis represents time. When the pressure measured by the pressure sensor 11 reaches a control upper limit pressure P1 lower than the high pressure upper limit Pmax, the control device 10 opens the bypass solenoid valve 7 to cause the bypass circuit 6 to function (refrigerant is also supplied to the bypass circuit 6). Inflow) to reduce high pressure.
Further, when the bypass solenoid valve 7 is open, when the pressure measured by the pressure sensor 11 reaches the control lower limit pressure P2 lower than the predetermined control upper limit pressure P1, the control device 10 shuts off the bypass solenoid valve 7. Then, the refrigerant flow into the bypass circuit 6 is stopped.

By measuring the high pressure with the pressure sensor 11 and controlling the opening and closing of the bypass solenoid valve 7 according to the pressure value, it is possible to reliably avoid an excessive increase in the high pressure during overload operation. In addition, since the bypass solenoid valve 7 is not opened excessively, the optimum amount of enclosed refrigerant can be maintained for a long time, and high-efficiency operation can be performed for a long time.
In the above description, the bypass solenoid valve 7 is described as switching between refrigerant flow and blockage. However, the present invention is not limited to this, and the refrigerant flow rate is adjusted (the flow rate is zero). It may be a flow control valve.

(Bypass receiver)
In the refrigerating and air-conditioning apparatus 100, since the bypass receiver 8 for storing the refrigerant branched from the branch point 12 is installed in the bypass circuit 6, it becomes possible to store a large amount of refrigerant and suppress high pressure during overload operation. It is possible to further increase the effect of avoiding the excessive increase in high pressure. Even if the bypass receiver 8 is removed, the refrigerant is stored in the bypass circuit 6 (precisely, in the piping forming the bypass circuit), so the bypass receiver 8 may be removed.

  Furthermore, although the connection position to the bypass receiver 8 of the refrigerant | coolant inflow pipe 6a which flows in a refrigerant | coolant into the bypass receiver 8, and the refrigerant | coolant discharge pipe 6b which discharges | emits a refrigerant | coolant from the bypass receiver 8 is not limited, For example, a refrigerant | coolant discharge pipe 6b may be connected to the bottom surface of the container forming the bypass receiver 8 or near the bottom surface (corresponding to the lower portion). At this time, when the refrigerant stored in the bypass receiver 8 is returned to the main circuit 101, the refrigerating machine oil flowing into the bypass receiver 8 can be discharged together with the refrigerant. For this reason, an appropriate amount of refrigerating machine oil can always be supplied to the compressor 1, and machine damage of the compressor 1 due to oil depletion can be avoided. By keeping the amount of oil in the compressor 1 at an appropriate amount, a more reliable refrigeration air conditioner 100 can be obtained.

[Embodiment 2]
FIG. 4 is a refrigerant circuit diagram showing a configuration for explaining a refrigerating and air-conditioning apparatus according to Embodiment 2 of the present invention. In FIG. 4, the refrigeration air conditioner 200 is provided with a gas vent pipe 14 in addition to the refrigerant discharge pipe 6b. One end of the gas vent pipe 14 is connected to the ceiling surface of the container forming the bypass receiver 8, and the other end is connected between the evaporator 4 of the main circuit 101 and the compressor 1 (in FIG. (It is connected between the bypass pressure reducing means 9 of the discharge pipe 6b and the junction 13).
That is, by installing the gas vent pipe 14, when the bypass solenoid valve 7 is opened during an overload operation, the refrigerant storage in the bypass receiver 8 is more effectively promoted than when the bypass receiver 8 is simply kept at a low pressure. Is obtained. This quickly suppresses high pressure during overload operation and improves reliability.

Further, as shown in FIG. 4, a degassing decompression means 15 is installed in the degassing pipe 14. For this reason, even if the bypass receiver 8 becomes full of liquid refrigerant and the liquid refrigerant is discharged from the degassing pipe 14, the flow rate is adjusted by the degassing decompression means 15, and the liquid is supplied to the suction portion of the compressor 1. There will be no return.
In addition, if the bypass receiver 8 is in a full liquid state, it is possible to secure a degree of supercooling in the refrigerant flowing into the capillary tube 3 installed in the main circuit 101, so that the capillary tube 3 flows in a gas-liquid two-phase state. It is possible to avoid a decrease in the flow rate due to the operation and a decrease in operation efficiency due to poor distribution.

And the bypass receiver 8 can be filled up and it becomes possible to prevent the fall of operating efficiency.
In addition, the capacity | capacitance of the bypass receiver 8 is set so that a high voltage | pressure can be suppressed reliably even if it fills up at the time of an overload driving | operation. As a result, high pressure can be suppressed by the operation that fills the bypass receiver 8 and it is possible to prevent a decrease in operating efficiency.

Further, the flow resistance of the degassing decompression means 15 is made smaller than that of the bypass decompression means 9. That is, the degassing decompression means 15 is made shorter than the bypass decompression means 9, or the pipe diameter is increased.
When the flow resistance of the degassing decompression means 15 is small, the gas flow rate flowing through the gas vent pipe 14 increases. When the flow resistance of the bypass decompression means 9 is large, the liquid flow rate flowing through the bypass circuit 6 decreases. Therefore, when the refrigerant is stored in the bypass receiver 8, the gas can be quickly extracted and the liquid can be stored. This quickly suppresses high pressure during overload operation and improves reliability.
In the above, the degassing pipe 14 is connected to the ceiling surface of the container forming the bypass receiver 8, but the same effect can be obtained even if it is connected near the ceiling surface (corresponding to the upper part of the bypass receiver 8). An effect is obtained.

[Embodiment 3]
FIG. 5 is a refrigerant circuit diagram showing a configuration for explaining a refrigerating and air-conditioning apparatus according to Embodiment 3 of the present invention. In FIG. 5, the refrigerant | coolant exhaust pipe 6b is connected to the refrigeration air conditioner 300 at the ceiling surface of the container which forms the bypass receiver 8 installed in the bypass circuit 6. In FIG. Therefore, if the bypass receiver 8 becomes full, the degree of supercooling can be ensured for the refrigerant flowing into the capillary tube 3 of the main circuit 101. For this reason, in the capillary 3, it is possible to avoid a decrease in passage flow rate due to inflow in a gas-liquid two-phase state and a decrease in operation efficiency due to poor distribution.
For this reason, since the connection becomes easier than connecting the refrigerant discharge pipe 6b to the bottom surface of the container forming the bypass receiver 8, the cost can be reduced.

[Embodiment 4]
6 and 7 illustrate a refrigerating and air-conditioning apparatus according to Embodiment 4 of the present invention. FIG. 6 is a refrigerant circuit diagram showing the configuration, and FIG. 7 is a cross-sectional view schematically showing an enlarged part. FIG.
6 and 7, in the refrigerating and air-conditioning apparatus 400, the refrigerant discharge port 8b is formed on the ceiling surface of the container that forms the bypass receiver 8 installed in the bypass circuit 6, and the refrigerant discharge port 8b passes through the refrigerant discharge port 8b. The pipe 6b has entered the bypass receiver 8.
In the refrigerant discharge pipe 6b, a range 6c that has entered the bypass receiver 8 is formed in a substantially J-shape, and the tip (located at the top) is the gas discharge port 6d. Further, an oil return hole 6e for discharging the refrigerating machine oil staying in the bypass receiver 8 is provided in a curved lowermost portion.
Thereby, when the refrigerant stored in the bypass receiver 8 is returned to the main circuit 101 (returned to the suction portion of the compressor 1 via the junction 13), the refrigerating machine oil staying in the bypass receiver 8 becomes the oil return hole 6e. And can be discharged together with the refrigerant. That is, since an appropriate amount of refrigeration oil can always be supplied to the compressor 1, damage to the compressor 1 due to oil depletion can be avoided. Therefore, a more reliable refrigeration air conditioner 400 can be obtained by maintaining an appropriate amount of oil in the compressor 1.

[Embodiment 5]
FIG. 8 is a refrigerant circuit diagram showing a configuration for explaining a refrigerating and air-conditioning apparatus according to Embodiment 5 of the present invention. In FIG. 8, when the liquid refrigerant is directly returned from the bypass receiver 8, the refrigerating and air-conditioning apparatus 500 has a bypass decompression unit 9 and a vent pipe in the bypass circuit 6 for the purpose of avoiding the occurrence of liquid return to the compressor 1. A heat exchanger 17 that supplies warm heat to the refrigerant downstream of 14 is installed. That is, the heat held by the refrigerant (high pressure / intermediate temperature) flowing out of the condenser 2 is transferred to the refrigerant after passing through the bypass pressure reducing means 9.

  Note that if the junction 13 can be upstream of the evaporator 4, evaporation can be promoted by the evaporator 4 even if the liquid refrigerant merges. However, in the configuration of the capillary 3 that serves both for decompression and distribution, upstream of the evaporator 4. The junction 13 cannot be installed on the side.

(Heat exchanger)
The heat exchanger 17 communicates between the high pressure piping part communicating between the condenser 2 of the main circuit 101 and the branch point 12, and between the bypass pressure reducing means 9 and the gas vent pipe 14 of the bypass circuit 6 and the junction 13. And a part of the refrigerant discharge pipe 6b to be thermally connected to each other. The configuration of the heat exchanger 17 is not limited. For example, the heat exchanger 17 is formed from a copper tube having a double-pipe structure, and the inner tube is a high-pressure pipe portion, and is an outer portion that houses the inner tube. The pipe may be a part of the refrigerant discharge pipe 6b. At this time, heat exchange is promoted if the direction of the refrigerant flowing inside each is made to be a counter flow.

Therefore, the refrigerant flowing through the former (high pressure and intermediate temperature) is cooled to promote liquefaction, and the refrigerant flowing through the latter (low pressure and low temperature) is heated to promote gasification.
As a result, the high pressure suppression effect is increased, and the liquid refrigerant can be efficiently stored in the bypass receiver 8. Since the liquid refrigerant is stored in the bypass receiver 8 and can be surely filled with liquid, the degree of supercooling of the refrigerant flowing into the capillary 3 can be ensured. Therefore, in the main circuit 101, it is possible to avoid a decrease in passage flow rate due to the inflow in the gas-liquid two-phase state in the capillary 3 and a decrease in operation efficiency due to poor distribution.
Further, in the bypass circuit 6, the refrigerant flowing out of the bypass receiver 8 evaporates, so that liquid return to the compressor 1 can be avoided.

[Embodiment 6]
FIG. 9 is a refrigerant circuit diagram showing a configuration for explaining a refrigerating and air-conditioning apparatus according to Embodiment 6 of the present invention. In FIG. 9, the refrigeration air conditioner 600 is obtained by moving the heat exchanger 17 in the refrigeration air conditioner 500 from the upstream of the branch point 12 to the downstream of the branch point 12.
At this time, since the heat exchanger 17 is downstream from the branch point 12, the degree of supercooling can be ensured downstream of the heat exchanger 17 even if the bypass receiver 8 is not full. Thereby, in the capillary 3, it is possible to avoid a decrease in the passage flow rate due to the inflow in the gas-liquid two-phase state and a decrease in the operation efficiency due to poor distribution.

[Embodiment 7]
FIG. 10 is a refrigerant circuit diagram showing a configuration for explaining a refrigerating and air-conditioning apparatus according to Embodiment 7 of the present invention. In FIG. 10, the refrigerating and air-conditioning apparatus 700 has a bypass evaporator 20 installed downstream of the bypass decompression means 9 of the bypass circuit 6. The bypass evaporator 20 receives the heat held by indoor air or outdoor air. Therefore, in the bypass circuit 6, the refrigerant flowing out of the bypass receiver 8 is heated and evaporates, so that liquid return to the compressor 1 can be avoided.
The bypass evaporator 20 is disposed at a position exposed to an air flow formed by an evaporator fan (not shown) that sends room air to the evaporator 4 or a condenser fan (not shown) that sends outdoor air to the condenser 2. Then, heat exchange by forced convection can be performed. Thereby, heat exchange with a larger amount of heat is possible.

[Others]
As described above, in the first to seventh embodiments, the types of the bypass pressure reducing means 9 and the degassing pressure reducing means 15 are not limited, but one or a plurality of capillaries (capillary tubes) or variable expansion valves (for example, temperature type) Expansion valve or electronic expansion valve). Moreover, the heat exchanger 17 and the bypass evaporator 20 can be installed in Embodiments 1-4, and do not limit the model.

  According to the present invention, an excessive increase in high pressure during overload operation can be avoided, and reliability during overload operation can be ensured. Therefore, it can be widely used as various refrigeration and air conditioners for home use and business use. it can.

The refrigerant circuit figure which shows the structure of the refrigerating air conditioner which concerns on Embodiment 1 of this invention. The refrigerant circuit diagram which shows the refrigerant | coolant flow in the refrigerant circuit diagram shown in FIG. The figure which shows the effect | action of the control apparatus in the refrigerant circuit diagram shown in FIG. The refrigerant circuit figure which shows the structure of the refrigerating air conditioning apparatus which concerns on Embodiment 2 of this invention. The refrigerant circuit figure which shows the structure of the refrigerating air conditioning apparatus which concerns on Embodiment 3 of this invention. The refrigerant circuit figure which shows the structure of the refrigerating air conditioning apparatus which concerns on Embodiment 4 of this invention. Sectional drawing which expands and shows a part of refrigeration air conditioning apparatus which concerns on Embodiment 4 of this invention. The refrigerant circuit figure which shows the structure of the refrigerating air conditioning apparatus which concerns on Embodiment 5 of this invention. The refrigerant circuit figure which shows the structure of the refrigerating air conditioning apparatus which concerns on Embodiment 6 of this invention. The refrigerant circuit figure which shows the structure of the refrigerating air conditioning apparatus which concerns on Embodiment 7 of this invention.

Explanation of symbols

  1: compressor, 2: condenser, 3: capillary tube (pressure reduction means), 4: evaporator, 6: bypass circuit, 6a: refrigerant inlet pipe, 6b: refrigerant outlet pipe, 6c: substantially J-shaped range, 6d : Gas discharge port, 6e: Oil return hole, 7: Bypass solenoid valve, 8: Bypass receiver, 8b: Refrigerant discharge port, 9: Bypass pressure reducing means, 10: Control device, 11: Pressure sensor, 12: Branch point, 13 : Confluence, 14: Degassing pipe, 15: Degassing decompression means, 17: Heat exchanger, 18: Outdoor unit, 19: Indoor unit, 100: Refrigerating air conditioner (Embodiment 1), 101: Main circuit, 200: Refrigeration air conditioner (Embodiment 2), 300: Refrigeration air conditioner (Embodiment 3), 400: Refrigeration air conditioner (Embodiment 4), 500: Refrigeration air conditioner (Embodiment 5), 600: Refrigeration air conditioner (Embodiment 6), 700: Refrigeration air conditioner ( Form of facilities 7).

Claims (17)

A compressor that compresses and discharges the refrigerant; a condenser that condenses the refrigerant discharged from the compressor; a decompression unit that decompresses the refrigerant that flows out of the condenser; and a refrigerant that is decompressed by the decompression unit. An evaporator for evaporating, and a main circuit for sequentially circulating the refrigerant by connecting them,
A bypass circuit that communicates a branch point provided between the condenser of the main circuit and the decompression means and a junction point provided between the evaporator and the compressor of the main circuit; Have
The decompression means comprises a plurality of capillaries,
The evaporator includes a heat transfer tube communicating with each of the capillaries,
In the bypass circuit, in order from the branch point toward the junction, a bypass solenoid valve and a bypass pressure reducing means for decompressing the refrigerant are installed,
The main circuit is provided with a pressure sensor for measuring the pressure of the refrigerant discharged from the compressor,
A refrigerating and air-conditioning apparatus comprising: a control device that inputs a pressure value measured by the pressure sensor and controls opening and closing of the bypass electromagnetic valve according to the pressure value. An outdoor unit comprising the compressor, the condenser, the bypass circuit, and the control device;
An indoor unit comprising the decompression means and the evaporator;
The refrigerating and air-conditioning apparatus according to claim 1, further comprising:   The refrigerating and air-conditioning apparatus according to claim 1 or 2, wherein a bypass receiver for storing refrigerant is installed between the bypass solenoid valve and the bypass pressure reducing means in the bypass circuit.   The refrigerating and air-conditioning apparatus according to claim 3, wherein one end of a refrigerant discharge pipe constituting the bypass circuit is connected to a lower portion of the bypass receiver.   The refrigerating and air-conditioning apparatus according to claim 3 or 4, further comprising a gas vent pipe having one end connected to an upper portion of the bypass receiver and the other end connected to the main circuit.   The refrigerating and air-conditioning apparatus according to claim 5, wherein a degassing / reducing unit that depressurizes the refrigerant is installed in the degassing pipe.   The refrigerating and air-conditioning apparatus according to claim 6, wherein a flow resistance of the degassing decompression unit is smaller than a flow resistance of the bypass decompression unit.   The refrigerating and air-conditioning apparatus according to claim 3, wherein one end of a refrigerant discharge pipe constituting the bypass circuit is connected to an upper portion of the bypass receiver. One end of the refrigerant discharge pipe constituting the bypass circuit penetrates into the inside from the upper part of the bypass receiver, and the entered area is bent into a substantially J shape,
The refrigerating and air-conditioning apparatus according to claim 3, wherein an oil outlet is formed at a position near the lower portion of the bypass receiver in the J-shaped portion.   There is provided a heat exchanger in which the refrigerant flowing between the bypass depressurization means of the bypass circuit and the junction receives heat from the refrigerant flowing between the condenser and the branch point of the main circuit. The refrigerating and air-conditioning apparatus according to any one of claims 1 to 9.   There is provided a heat exchanger in which the refrigerant flowing between the bypass pressure reducing means and the junction of the bypass circuit receives warm heat from the refrigerant flowing between the branch point of the main circuit and the pressure reducing means. The refrigerating and air-conditioning apparatus according to any one of claims 1 to 9.   The refrigerating and air-conditioning apparatus according to any one of claims 1 to 9, wherein the refrigerant that has flowed out of the bypass pressure-reducing means of the bypass circuit includes a heat exchanger that receives warm heat held by the atmosphere.   A heat exchanger is provided in which the refrigerant flowing between the degassing decompression unit of the degassing pipe and the main circuit receives warm heat from the refrigerant flowing between the condenser and the branch point of the main circuit. The refrigeration air conditioner according to any one of claims 6 to 9.   A heat exchanger is provided in which the refrigerant flowing between the degassing decompression unit of the degassing pipe and the main circuit receives warm heat from the refrigerant flowing between the branch point of the main circuit and the decompression unit. The refrigeration air conditioner according to any one of claims 6 to 9.   The refrigerating and air-conditioning apparatus according to any one of claims 6 to 9, further comprising a heat exchanger in which the refrigerant that has flowed out of the degassing decompression unit of the degassing pipe receives warm heat held by the atmosphere.   The refrigerating and air-conditioning apparatus according to any one of claims 1 to 3, wherein the bypass pressure reducing means is a capillary tube or a variable expansion valve.   The refrigerating and air-conditioning apparatus according to claim 6, wherein the degassing decompression means is a capillary tube or a variable expansion valve.

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