JPH10253171A - Air conditioner - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In an air conditioner using a refrigerant that does not destroy the ozone layer, the reliability of the device is reduced due to moisture mixed in a refrigeration cycle. Further, the improvement of the operation efficiency at the time of operation under the intermediate load condition and the improvement of the operation efficiency at the time of operation under the high load condition are not compatible. SOLUTION: In an air conditioner in which a compressor 1, a condenser 2, a main decompressor 3, and an evaporator 4 are pipe-connected, a bypass circuit branched at a branch point 28 and connected to a main circuit at a connection point 29,
A sub-pressure reducer 5, an auxiliary heat exchanger 6, and a dryer 7 are used, and a single refrigerant or a mixed refrigerant containing no chlorine in the molecule is used as a refrigerant.
And the refrigerant between the sub decompressor 5 and the connection point 29 is subjected to heat exchange. The bypass flow controller 8 controls the sub depressurizer 5 based on the operating load of the compressor. And at least one of the evaporator 4 and the condenser 2 has a structure in which the flow path of the refrigerant is increased by narrowing the flow path of the refrigerant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a compressor, a condenser,
The present invention relates to an air conditioner that forms a refrigeration cycle by connecting a main decompressor and an evaporator with piping.

[0002]

2. Description of the Related Art Conventionally, HCF has been used as a refrigerant for air conditioners.
C22 (R22) is widely used, and an air conditioner as shown in FIG. 3 has been proposed to increase the degree of supercooling at the inlet of the pressure reducer.

FIG. 3 is a schematic diagram showing a configuration of a conventional air conditioner. In FIG. 3, reference numeral 21 denotes a compressor, 22 denotes a condenser, 23 denotes a main decompressor, and 24 denotes an evaporator. A refrigeration cycle is constituted by a main circuit connected to these pipes.
A bypass circuit is provided which branches off from a branch point 30 between the condenser 22 and the main decompressor 23 and joins the main circuit again at a connection point 31 near the suction part of the compressor 21. An auxiliary pressure reducer 25 and an auxiliary heat exchanger 26 are provided on the bypass circuit. The auxiliary heat exchanger 26 includes a refrigerant between the branch point 30 and the main decompressor 23 and a sub-depressor 25
Since the heat exchange between the refrigerant and the connection point 31 is performed on the main circuit between the branch point 30 and the main pressure reducer 23, the refrigerant is disposed on the bypass circuit described above. I have. Furthermore, HCFC is generally used as a refrigerant.
22 (R22) is enclosed.

Next, the operation of such a conventional air conditioner will be described. The refrigerant is compressed by the compressor 21 to become high temperature and high pressure, radiates heat in the condenser 22 to be condensed and liquefied, passes through the auxiliary heat exchanger 26, is depressurized by the main decompressor 23, and becomes a two-phase state of low temperature and low pressure, and evaporates The heat is absorbed by the evaporator 24, evaporated and vaporized, and sucked into the compressor 21 again. A part of the refrigerant condensed and liquefied in the condenser 22 is decompressed by the sub-pressure reducer 25 to be in a low-temperature and low-pressure two-phase state, and the auxiliary heat exchanger 26 supercools the refrigerant at the inlet of the main pressure reducer 23. Is evaporated by the
At 1, the refrigerant merges with the refrigerant evaporated by the evaporator 24 and is sucked into the compressor 21. At this time, the refrigerant at the inlet of the main decompressor 23 is supercooled, so that the enthalpy at the inlet of the evaporator 24 decreases. That is, the enthalpy difference between the inlet and the outlet of the evaporator 4 increases, and even if the refrigerant flowing out of the condenser 22 is partially bypassed to the sub-pressure reducing device 25 and the flow rate of the refrigerant flowing through the evaporator 24 is reduced. The same evaporator capacity can be ensured, and the flow rate of the refrigerant flowing through the evaporator 24 is reduced, so that the pressure loss at the main decompressor 23 to the evaporator 24 to the compressor 21 suction section can be reduced, and the operating efficiency can be improved.

[0005]

However, HCF which has been conventionally used as a refrigerant for air conditioners has been used.
The use of C22 (R22) is regulated in order to destroy the stratospheric ozone layer, and refrigerants that do not contain chlorine in the molecule have attracted attention as alternative refrigerants. However, these refrigerants have poor compatibility with mineral oils conventionally used for lubricating oils in compressors, and ester-based or ether-based lubricating oils have been newly developed. However, ester-based lubricating oils are hydrolyzed by water mixed in the refrigeration cycle to generate acids, generate metal salts, and cause capillaries and the like. On the other hand, ether-based lubricating oils have a high hygroscopicity, and thus may introduce moisture into the refrigeration cycle, and this moisture has a problem that organic materials such as insulating films in the compressor are deteriorated.

[0006] Further, HFC-based refrigerants have been developed as refrigerants containing no chlorine in the molecule, and it has become possible to prevent ozone layer depletion. However, these refrigerants have the global warming potential of the conventional HCFC22 ( R22), it is necessary to improve the operation efficiency of the air conditioner and reduce the power consumption in order to prevent global warming. Of the actual annual power consumption of the air conditioner, the ratio of power consumption during operation under so-called intermediate load conditions below the rated capacity and during operation under high load conditions is large. A reduction in power consumption during operation under load conditions and a reduction in power consumption during operation under high load conditions must both be achieved. However, in the conventional air conditioner as shown in FIG. 3, the supercooling at the inlet of the main decompressor 23 can be increased at the time of operation near the rated capacity or under a high load condition, and a part of the refrigerant exiting the condenser 22 can be increased. Is introduced into the suction section of the compressor 21 through the sub-pressure reducer 25 and the auxiliary heat exchanger 26, whereby the evaporator 24 can be bypassed, and the main pressure reducer 23 to the evaporator 24 to the suction of the compressor 21 The pressure loss to the section can be reduced and the operation efficiency can be improved. However, during operation under the intermediate load condition, the effect of the pressure loss reduction is small because the flow rate of the refrigerant is small. Therefore, there is a problem that the heat transfer coefficient of the evaporator 24 is reduced due to a decrease in the flow rate of the refrigerant in the evaporator 24 and the operation efficiency is reduced. The problem at the time of the operation under the intermediate load condition described above is not only the air conditioner using the refrigerant containing no chlorine in the molecule but also the conventional one using HCFC22 (R22) as the refrigerant as shown in FIG. Air conditioners were also mentioned as issues.

[0007] The present invention considers the problem caused by moisture mixed in a refrigeration cycle of an air conditioner using a refrigerant containing no chlorine in its molecules, and removes the moisture mixed in the refrigeration cycle. It is an object of the present invention to provide an air conditioner that uses a refrigerant that does not destroy the ozone layer and that improves reliability.

Further, the present invention considers the problem when operating an air conditioner under an intermediate load condition, and improves the operation efficiency in an operation under an intermediate load condition and the operation efficiency in an operation under a high load condition. It is an object of the present invention to provide an air conditioner that achieves both.

[0009]

According to a first aspect of the present invention, there is provided an air conditioner in which a compressor, a condenser, a main decompressor, and an evaporator are connected by piping, between the condenser and the main decompressor. A bypass circuit branching from the disposed branch point and connected to a connection point disposed between the evaporator and the suction portion of the compressor, and a sub-pressure reducer disposed in the bypass circuit, An auxiliary heat exchanger disposed in the bypass circuit downstream of the sub-pressure reducer, and disposed between the branch point and the main pressure reducer; and disposed between the condenser and the evaporator. With a dryer for the purpose of capturing moisture, using a single refrigerant or a mixed refrigerant containing no chlorine in the molecule as a refrigerant, and a refrigerant between the branch point and the main decompressor by the auxiliary heat exchanger. From the sub-pressure reducer to the connection point The refrigerant between an air conditioner which comprises causing heat exchange.

According to a third aspect of the present invention, there is provided an air conditioner in which a compressor, a condenser, a main decompressor, and an evaporator are connected by piping, from a branch point disposed between the condenser and the main decompressor. A bypass circuit branching off and connected to a connection point disposed between the evaporator and the suction section of the compressor, a sub-pressure reducer disposed in the bypass circuit, and a downstream of the sub-pressure reducer. An auxiliary heat exchanger that is disposed in the bypass circuit on the side, and that is disposed between the branch point and the main pressure reducer, and a bypass that controls the sub-pressure reducer according to an operation load state of the compressor. A flow controller, wherein the auxiliary heat exchanger causes heat exchange between the refrigerant between the branch point and the main decompressor and the refrigerant between the sub-pressure reducer and the connection point. It is an air conditioner.

[0011]

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

FIG. 1 is a schematic diagram showing a configuration of an air conditioner according to a first embodiment of the present invention. In FIG.
1 is a compressor, 2 is a condenser, 3 is a main decompressor, 4 is an evaporator, and a refrigeration cycle is constituted by a main circuit connected to these by piping. A bypass circuit 20 is provided, which branches off from a branch point 28 between the condenser 2 and the main decompressor 3 and joins the main circuit again at a connection point 29 near the suction part of the compressor 1; The auxiliary pressure reducer 5 and the auxiliary heat exchanger 6 are provided on the bypass circuit 20. Since the auxiliary heat exchanger 6 exchanges heat between the refrigerant between the branch point 28 and the main pressure reducer 3 and the refrigerant between the sub-pressure reducer 5 and the connection point 29, the auxiliary heat exchanger 6 , And also on the main circuit between the branch point 28 and the main decompressor 3. The air conditioner in the present embodiment uses a single refrigerant or a mixed refrigerant that does not contain chlorine in the molecule as the refrigerant. Reference numeral 7 denotes a dryer in which a moisture capturing agent (not shown) for capturing moisture is sealed. The bypass flow controller 8 controls the sub-pressure reducer 5 according to the operating load state of the compressor 1.

Next, the operation of the embodiment will be described. The refrigerant is compressed by the compressor 1 to become high temperature and high pressure,
The heat is radiated by the condenser 2 and condensed and liquefied. The pressure is reduced by the main decompressor 3 through the auxiliary heat exchanger 6 and the dryer 7 to be in a low-temperature and low-pressure two-phase state. It is sucked into the compressor 1 again. A part of the refrigerant condensed and liquefied in the condenser 2 is decompressed by the sub-pressure reducer 5 to be in a low-temperature and low-pressure two-phase state, and the auxiliary heat exchanger 6 supercools the refrigerant at the inlet of the main pressure reducer 3. The refrigerant evaporates at the suction portion of the compressor 1 and merges with the refrigerant evaporated by the evaporator 4 to be sucked into the compressor 1.

At this time, the dryer 7 captures the moisture introduced into the refrigeration cycle. However, if the flow rate of the refrigerant in the dryer 7 is high, the moisture capturing agent (such as molecular sieve) in the dryer 7 deteriorates or wears. In addition, if the flow rate is low, a problem is expected that it takes a long time to capture the mixed water. However, in the present embodiment, since the dryer 7 is provided between the condenser 2 and the evaporator 4, the refrigerant here is in a two-phase state in a liquid state or a state in which a large amount of liquid having a small dryness is present. Therefore, the flow velocity is lower than that of the refrigerant between the evaporator 4 to the compressor 1 to the condenser 2 which is in a gaseous state, and the refrigerant flow velocity in the dryer 7 is kept at an appropriate level, and the refrigerant flow velocity in the dryer 7 is abnormally high. It is possible to capture moisture mixed in the refrigeration cycle while preventing deterioration and abrasion of a moisture capturing agent (not shown) that occurs as a result.

Preferably, the dryer 7 is connected to the condensers 2 to
The refrigerant flow condensed and liquefied in the condenser 2 is introduced into the dryer 7 until the pressure is reduced by the main decompressor 3 to form a two-phase state. It is possible to capture moisture mixed in the refrigeration cycle while further preventing deterioration and wear of a moisture capturing agent (not shown) caused by an abnormally high flow rate of the refrigerant in the dryer 7.

Alternatively, preferably, the dryer 7 is connected to the condenser 2.
Between the evaporator 4 and the branch point 28 between the evaporator 4 and the main decompressor 3, a part of the refrigerant exiting the condenser 2 is
Since the flow rate of the refrigerant introduced into the dryer 7 is slightly reduced due to the flow through the bypass circuit 20 on the side, the flow velocity of the refrigerant in the dryer 7 is maintained at an appropriate level, and the moisture generated due to the abnormally high flow velocity of the refrigerant in the dryer 7 It is possible to capture moisture mixed in the refrigeration cycle while preventing deterioration and wear of the capturing agent (not shown).

More desirably, a dryer 7 is provided between a branch point 28 between the condenser 2 and the main decompressor 3 and the main decompressor 3, so that a part of the refrigerant exiting the condenser 2 is sub-depressurized. Until the refrigerant condensed and liquefied in the condenser 2 is reduced in pressure by the main decompressor 3 to be in a two-phase state because the flow rate of the refrigerant introduced into the dryer 7 is slightly reduced because the refrigerant flows into the bypass circuit 20 on the side of the vessel 5. In this case, the flow rate of the refrigerant in the dryer 7 is further appropriately maintained, and the flow rate of the refrigerant in the dryer 7 becomes abnormally high even when the compressor 1 operates at a high load. It is possible to capture moisture mixed in the refrigeration cycle while preventing deterioration and wear of the moisture capturing agent (not shown).

More desirably, a dryer 7 is provided between the auxiliary heat exchanger 6 and the main decompressor 3, and the refrigerant introduced into the dryer 7 is reliably cooled by the auxiliary heat exchanger 6 because it is supercooled. In the two-phase state, the gas refrigerant existing in the dryer 7 is eliminated, so that the flow rate of the refrigerant in the dryer 7 is maintained at a more appropriate level. The moisture trapped in the refrigeration cycle can be trapped while preventing the deterioration and wear of the water trapping agent (not shown) caused by the abnormally high flow velocity.

In any of the above cases, the dryer 7
Is provided not in the bypass circuit 20 but in the main circuit, so that the problem that it takes a long time to capture the mixed water due to the abnormally low flow velocity in the dryer 7 while avoiding the problem in the refrigeration cycle. The mixed water can be captured.

Next, the operation of the bypass flow controller 8 will be described.

The bypass flow rate controller 8 detects the operating load of the compressor 1 and adjusts the bypass flow rate flowing to the auxiliary pressure reducer 5 according to the detected operating load. As a method of detecting the operating load, the number of operating compressors is used when the compressor 1 is a plurality of compressors, the number of operating poles is used when the compressor 1 is an extreme variable compressor, and the operating frequency is used when the compressor 1 is an inverter compressor. Is determined based on each of these. Although not shown, in addition to the above, the operation of the compressor is performed based on the temperature and pressure of the refrigeration cycle and the ambient temperature of the condenser 2 and the evaporator 4 (in the case of an air-cooled type, the intake air temperature, etc.). The load may be determined.

First, when the air conditioner is operated at a high load and the operating load of the compressor 1 is high, the bypass flow controller 8 reduces the pressure reduction amount of the sub-pressure reducer 5. That is, the sub-pressure reducer 5
If is an expansion valve, the opening is increased. Then sub decompressor 5
The flow rate of the bypass circuit 20 on the side increases, and the flow rate of the main circuit on the side of the main pressure reducer 3 decreases. However, since the amount of heat exchange in the auxiliary heat exchanger 6 increases, the degree of supercooling of the refrigerant at the inlet of the main decompressor 3 increases, that is, the enthalpy difference between the inlet and the outlet of the evaporator 4 increases. While the capacity of the evaporator is maintained, the pressure loss at the suction part of the main decompressor 3, the evaporator 4, and the compressor 1 is reduced, and the operation efficiency can be improved. When the dryer 7 is provided between the branch point 28 and the evaporator 4, when the operating load of the compressor 1 is high, that is, when the refrigerant flow rate is high, the flow rate of the bypass circuit 20 is increased to suppress the increase in the flow rate of the main circuit. As a result, the flow rate of the refrigerant in the dryer 7 is maintained at an appropriate level, and the deterioration and wear of the moisture trapping agent in the dryer 7 can be prevented.

Next, when the air conditioner is operated under the intermediate load condition and the operation load of the compressor 1 is low, the bypass flow controller 8 increases the pressure reduction amount of the sub-pressure reducer 5. That is, when the sub-pressure reducing device 5 is an expansion valve, the opening degree is reduced. Then, the flow rate of the bypass circuit 20 on the sub-pressure reducer 5 side decreases or becomes zero, and the flow rate of the main circuit on the main pressure reducer 3 side increases. That is, it is possible to avoid the problem that the heat transfer coefficient of evaporation is reduced due to the decrease in the flow velocity of the refrigerant in the evaporator 4 and to improve the operation efficiency. Also, the dryer 7 is connected to
When the compressor 1 is provided between the evaporators 4, when the operating load of the compressor 1 is low, that is, when the refrigerant flow rate is low, the flow rate of the bypass circuit 20 is reduced, or the flow rate of the main circuit is reduced to zero, and as a result, the flow rate is reduced. It is also possible to keep the flow rate of the refrigerant in the dryer 7 at an appropriate level, and to avoid the problem that it takes a long time to capture the mixed water.

Further, by forming the evaporator 4 with a narrow refrigerant passage such as a reduction in the diameter of the heat transfer tube or a decrease in the number of passes, the flow rate of the refrigerant can be increased and the heat transfer coefficient of the evaporator can be increased. Sometimes the operating efficiency can be further improved. When operating at a high load, the bypass flow rate controller 8 reduces the pressure reduction amount of the sub-pressure reducer 5 so that the bypass circuit 2
In order to increase the flow rate of zero and decrease the flow rate of the main circuit, it is possible to suppress an increase in pressure loss caused by configuring the evaporator 4 by narrowing the refrigerant flow path such as reducing the diameter of the heat transfer tube or reducing the number of passes. it can. That is, the operating efficiency under the intermediate load condition can be further improved, and the operating efficiency during the high load operation can be maintained or improved.

Alternatively, when the condenser 2 is configured such that the refrigerant flow path is narrowed, for example, by reducing the diameter of the heat transfer tube or reducing the number of passes, the flow rate of the refrigerant can be increased and the heat transfer rate of condensation can be increased. Sometimes the operating efficiency can be further improved. When operating at a high load, the pressure loss in the condenser 2 is not as large as the pressure loss in the evaporator 4, so that the refrigerant flow rate is increased and the condensing heat transfer coefficient is increased, so that the operating efficiency during the high load operation can be improved. Things.

Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic diagram showing a configuration of an air conditioner according to a second embodiment of the present invention. 2, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and the solid arrows in FIG. 2 indicate the flow of the refrigerant during the cooling operation, and the dashed arrows indicate the flow of the refrigerant during the heating operation. Show. In the air conditioner shown in FIG. 2, a single refrigerant or a mixed refrigerant containing no chlorine in molecules is sealed as a refrigerant, and 9
Is a four-way valve for switching between the cooling operation and the heating operation, and 10 is an outdoor heat exchanger, which functions as a condenser during the cooling operation and as an evaporator during the heating operation. An indoor heat exchanger 11 functions as an evaporator during a cooling operation and as a condenser during a heating operation. 12 is a first check valve, 13 is a second check valve, 14
Is a third check valve, and 15 is a fourth check valve, whereby the refrigerant condensed and liquefied in the outdoor heat exchanger 10 or the indoor heat exchanger 11 during the cooling operation and the heating operation is used as the auxiliary heat exchanger 6, After passing through the dryer 7 and the main decompressor 3, it is evaporated and vaporized in the indoor heat exchanger 11 or the outdoor heat exchanger 10. That is, in the case of the cooling operation, the compressor 1, the four-way valve 9, the outdoor heat exchanger 10, the third check valve 14, the auxiliary heat exchanger 6, the dryer 7,
A refrigeration cycle is configured by a main circuit connected in order of the main pressure reducer 3, the fourth check valve 15, the indoor heat exchanger 11, and the four-way valve 9, and in a heating operation, the compressor 1, the four-way valve 9, Indoor heat exchanger 11, first check valve 12, auxiliary heat exchanger 6, dryer 7, main pressure reducer 3, second check valve 13, outdoor heat exchanger 1
A refrigeration cycle is constituted by a main circuit connected in the order of 0 and the four-way valve 9. The pipe is branched from a branch point 28 between the first check valve 12 or the third check valve 14 and the main decompressor 3, and the four-way valve 9 is connected again at a connection point 29 near the suction part of the compressor 1. Bypass circuit 20 that merges with the passed main circuit
The auxiliary pressure reducer 5 and the auxiliary heat exchanger 6 are provided on the bypass circuit 20. Auxiliary heat exchanger 6
Is for exchanging heat between the refrigerant between the branch point 28 and the main pressure reducer 3 and the refrigerant between the sub-pressure reducer 5 and the connection point 29. Are also arranged on the main circuit between the branch point 28 and the main pressure reducer 3.

Next, the operation of the embodiment will be described. When the condenser and the evaporator are switched between cooling and heating by switching the four-way valve 9, the outdoor heat exchanger 10 or the indoor heat exchanger 11 is used in both the cooling operation and the heating operation.
Is introduced into the dryer 7. Therefore, as described in the first embodiment, regardless of whether the operating load of the compressor 1 is high or low, the flow rate of the refrigerant in the dryer 7 is maintained at an appropriate level, and the moisture trapping agent (shown in FIG. (2) can be avoided.

Further, the operation efficiency can be improved by the bypass flow rate controller 8 both in the operation under the intermediate load condition and in the high load operation as in the first embodiment.

The switching of the four-way valve 9 causes the outdoor heat exchanger 10 and the indoor heat exchanger 11 to function as both an evaporator and a condenser. Therefore, for example, in the case where the refrigerant flow path of the outdoor heat exchanger 10 acting as a condenser during the cooling operation is configured to be narrow, the cooling flow rate is increased during the cooling operation, and the cooling operation efficiency is further improved by improving the condensation heat transfer coefficient. Pressure loss increases during heating operation,
In particular, the heating operation efficiency during high-load operation is reduced. However, in the present embodiment, during the heating operation under the intermediate load condition, the bypass flow controller 8 operates the sub-reducer 5 according to the operating load of the compressor 1 to adjust the flow rate of the bypass circuit 20. By narrowing the refrigerant flow path of the outdoor heat exchanger 10, it is possible to prevent a decrease in the evaporation heat transfer rate due to a decrease in the flow rate of the refrigerant in the outdoor heat exchanger 10, or to improve the heat transfer rate due to the increase in the flow rate of the refrigerant. During the load heating operation, the bypass flow controller 8 operates the sub-reducer 5 according to the operating load of the compressor 1 to adjust the flow rate of the bypass circuit 20, thereby preventing an increase in pressure loss and heating under an intermediate load condition. Both the operation efficiency during the operation and the operation efficiency during the high-capacity heating operation can be improved. That is, the operation efficiency can be further improved both in the cooling operation and the heating operation.

In this embodiment, the structure using four check valves has been described. However, the present invention is not limited to this. For example, even if a four-way valve is added instead of four check valves, the same applies. It is clear that the effect is obtained.

Further, in the first embodiment or the second embodiment, the auxiliary pressure reducer is described as, for example, an electronic expansion valve capable of adjusting the amount of pressure reduction. However, the present invention is not limited to this. A similar effect can be obtained by a combination of a capillary and a solenoid valve.

In the air conditioner of the present invention, in the first embodiment or the second embodiment, a single refrigerant or a mixed refrigerant containing no chlorine in a molecule is used as a refrigerant. It has been described as having a dryer to remove unwanted moisture entering the cycle. That is, an air conditioner corresponding to claim 1 (or a dependent claim 2 or 4) has been described. However, in the above-described embodiment, an air conditioner that does not include a dryer is used as the HCFC22 (R22), that is, an air conditioner that does not include undesirable moisture in the refrigeration cycle, such as HCFC22 (R22). In the air conditioner corresponding to claim 4), all the effects described in the above-described embodiment except for the effect related to the removal of water generated in the refrigeration cycle can be obtained.

[0034]

As is apparent from the above description, the first aspect of the present invention uses a refrigerant which does not destroy the ozone layer and has improved reliability by removing water mixed in the refrigeration cycle. An air conditioner can be provided.

Further, the present invention provides a refrigerant that does not destroy the ozone layer and achieves both improvement in operating efficiency during operation under intermediate load conditions and improvement in operation efficiency during operation under high load conditions. Can be provided.

Further, the present invention provides an HCFC that achieves both improvement in operation efficiency in operation under intermediate load conditions and improvement in operation efficiency in operation under high load conditions.
An air conditioner using a refrigerant as a refrigerant can be provided.

Further, according to the present invention, the heat transfer coefficient of evaporation or the heat transfer of condensation can be improved, and the increase in pressure loss in the evaporator can be suppressed. It is possible to provide an air conditioner that achieves both improvement of the operation efficiency and further improvement of the operation efficiency in the operation under a high load condition.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a configuration of an air conditioner according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Main pressure reducer 4 Evaporator 5 Secondary pressure reducer 6 Auxiliary heat exchanger 7 Dryer 8 Bypass flow controller 9 Four way valve 10 Outdoor heat exchanger 11 Indoor heat exchanger 12 First check valve 13 First Two check valve 14 Third check valve 15 Fourth check valve 20 Bypass circuit 28 Branch point 29 Connection point

Claims (4)

[Claims] In an air conditioner in which a compressor, a condenser, a main decompressor, and an evaporator are connected by piping, the air conditioner branches from a branch point disposed between the condenser and the main decompressor to form the evaporator. A bypass circuit connected to a connection point disposed between the compressor and the suction section of the compressor, a sub-pressure reducer disposed in the bypass circuit, and a bypass circuit downstream of the sub-pressure reducer. An auxiliary heat exchanger arranged and arranged between the branch point and the main decompressor, and a dryer arranged between the condenser and the evaporator for the purpose of capturing moisture, Using a single refrigerant or a mixed refrigerant containing no chlorine in the molecule as the refrigerant, between the branch point and the main decompressor by the auxiliary heat exchanger, and between the sub decompressor and the connection point Characterized by exchanging heat with the refrigerant And air conditioner. 2. The air conditioner according to claim 1, further comprising a bypass flow controller that controls the auxiliary pressure reducer according to an operation load state of the compressor. 3. An air conditioner in which a compressor, a condenser, a main decompressor, and an evaporator are connected by piping, wherein the evaporator branches off from a branch point disposed between the condenser and the main decompressor. A bypass circuit connected to a connection point disposed between the compressor and the suction section of the compressor, a sub-pressure reducer disposed in the bypass circuit, and a bypass circuit downstream of the sub-pressure reducer. An auxiliary heat exchanger disposed between the branch point and the main decompressor, and a bypass flow controller that controls the sub-depressurizer according to the operating load state of the compressor. An air conditioner, wherein the auxiliary heat exchanger exchanges heat between a refrigerant between the branch point and the main decompressor and a refrigerant between the sub decompressor and the connection point. 4. The air conditioner according to claim 1, wherein at least one of the evaporator and the condenser has a structure in which a refrigerant flow path is narrowed to increase a refrigerant flow rate. .