JPH074794A - Air-conditioning equipment - Google Patents

Abstract

PURPOSE:To perform properly detection of frosting and a control of defrosting at the time of heating and thereby to improve a heating performance in a refrigerating cycle using a non-azeotropic mixture refrigerant. CONSTITUTION:An outdoor machine 1 is provided with a first outdoor heat exchanger 5 positioned on the windward of blowing of an outdoor blower 7 and with a second outdoor heat exchanger 6 positioned on the leeward thereof and these two outdoor heat exchangers 5 and 6 are connected in parallel, while a normally-closed bypass passage 13 for bypassing a discharge gas of a compressor is connected to the second outdoor heat exchanger 6. At the time of heating, the bypass passage 13 is opened on the basis of an inlet temperature of the second outdoor heat exchanger 6 or an outdoor temperature, so as to execute a control of defrosting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a heat pump type refrigerating cycle for exchanging heat between air and a refrigerant using a non-azeotropic mixed refrigerant and for cooling and heating the inside of a room.

[0002]

2. Description of the Related Art Many refrigeration cycles in air conditioners utilize the heat source of the atmosphere as the heat source for cooling and heating.
In general, an air conditioner equipped with this heat pump type refrigeration cycle draws heat from the atmosphere in the outdoor unit to release the heat from the indoor unit during heating, and conversely draws heat from the indoor unit into the outdoor unit to cool it during the cooling. Dissipating heat to the atmosphere. Therefore, when viewed as a refrigeration cycle, in the inverter model, the outdoor unit includes an inverter, a compressor, a throttle mechanism, a four-way valve, an outdoor heat exchanger,
The outdoor blower is installed in the indoor unit, and the indoor heat exchanger and the indoor blower are installed as main components. The performance of such an air conditioner largely depends on the heat exchanger performance of the indoor unit and the outdoor unit except for the compressor. Therefore,
Due to the recent housing situation, research and development of compact and high-performance heat exchangers with large space-savings for both indoor and outdoor units and low-noise and high-efficiency blowers are becoming mainstream in each company. In particular, in the indoor unit, the use of a small diameter pipe heat exchanger or the like has made it compact and highly efficient. On the other hand, the efficiency of the heat exchanger has been improved in the outdoor unit as well, but not so much as the indoor unit. This is because in the case of an outdoor unit, there is a problem of frosting during heating, and it is difficult to improve the heat exchange performance by making slits in the fins like in an indoor unit and making it multistage of three or more stages. There is also a cause.

Further, in recent years, from the viewpoint of global environmental protection of preventing ozone destruction and global warming,
There is a demand for a refrigerant that replaces R22 that has been conventionally used as a refrigerant for air conditioners. There are various candidates for alternative refrigerants whose cycle temperature and pressure are close to R22, but most of them are non-azeotropic mixed refrigerants, and this non-azeotropic mixed refrigerant has a temperature gradient at the time of refrigerant gas-liquid phase change. There is a drawback that heat transfer performance is inferior in terms of heat transfer. That is, in the heating heat pump operation that pumps up the heat of the atmosphere, when the outside air temperature is low, it freezes near the inlet of the outdoor heat exchanger and the effective temperature difference between the outside air temperature and the outdoor unit evaporation temperature becomes small. Inevitably, there is a problem that the heating capacity will be lower than when the value is high. Similarly, during cooling, the vicinity of the indoor heat exchanger is easily frozen when the cooling performance is low and the outside air temperature is low. Also,
It is necessary to optimize the flow rate control of the non-azeotropic mixed refrigerant during both heating and cooling to provide a stable refrigeration cycle.

[0004]

As described above, the conventional air conditioner having the refrigerating cycle using the non-azeotropic mixed refrigerant has the vicinity of the inlet of the outdoor heat exchanger when the outside air temperature is low during the heating operation. However, there is a problem that freezing easily occurs and the heating capacity decreases.

The present invention has been made in view of the above circumstances. An object of the present invention is to appropriately perform frost detection and defrost control during heating in a refrigeration cycle using a non-azeotropic mixed refrigerant. An object is to provide an air conditioner capable of improving the heating performance.

[0006]

In order to solve the above-mentioned problems, the present invention firstly provides an air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant, in which the outdoor unit blows air with an outdoor blower. A first outdoor heat exchanger located on the windward side and a second outdoor heat exchanger located on the leeward side, and the first and second outdoor heat exchangers are connected in parallel, A normally closed bypass path for bypassing the compressor discharge gas is connected to the second outdoor heat exchanger, and the bypass path is opened based on the inlet temperature or the outdoor temperature of the second outdoor heat exchanger during heating. The gist is that it is configured so as to perform defrosting control.

Secondly, in an air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant, the outdoor unit has a first outdoor heat exchanger located on the upwind side with respect to the air blown by the outdoor blower. And a second outdoor heat exchanger that is positioned, and the first and second outdoor heat exchangers are connected in series so that the first outdoor heat exchanger is on the upstream side with respect to the refrigerant flow during heating. And a normally closed bypass path for bypassing the compressor discharge gas is connected to the first outdoor heat exchanger,
The gist is that the defrosting control is performed by opening the bypass passage based on the inlet temperature or the outdoor temperature of the first outdoor heat exchanger during heating.

Thirdly, in an air conditioner having a refrigerating cycle using a non-azeotropic mixed refrigerant and having a four-way valve for setting a refrigerant route during cooling and heating, the outdoor unit is provided with a blower by an outdoor blower. A first outdoor heat exchanger located on the windward side and a second outdoor heat exchanger located on the leeward side are provided, and the first and second outdoor heat exchangers are connected in parallel to each other during heating. The four-way valve is reversed based on the inlet temperature or the outdoor temperature of the second outdoor heat exchanger, and the compressor discharge gas is guided to the second outdoor heat exchanger to perform defrost control. That is the summary.

Fourthly, in an air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant and having a throttle device for restricting the refrigerant flow between the indoor heat exchanger and the outdoor heat exchanger side, the outdoor unit Is provided with a first outdoor heat exchanger located on the windward side and a second outdoor heat exchanger located on the leeward side with respect to the air blown by the outdoor blower, and the first and second outdoor heat exchangers are provided. The gist is that the defrosting control is performed by connecting in parallel and loosening the throttle of the expansion device based on the inlet temperature or the outdoor temperature of the second outdoor heat exchanger during heating.

Fifth, in an air conditioner having a refrigerating cycle using a non-azeotropic mixed refrigerant and having a four-way valve for setting a refrigerant route during cooling and heating, the outdoor unit is provided with a blower by an outdoor blower. A first outdoor heat exchanger located on the windward side and a second outdoor heat exchanger located on the leeward side are provided, and the first outdoor heat exchanger is upstream with respect to the refrigerant flow during heating. As described above, the first and second outdoor heat exchangers are connected in series, and the four-way valve is reversed to the refrigerant flow side during cooling based on the inlet temperature or the outdoor temperature of the first outdoor heat exchanger during heating. The gist is that it is configured to perform defrost control.

Sixth, in the air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant and having a throttle device for restricting the refrigerant flow between the indoor heat exchanger and the outdoor heat exchanger side, the outdoor unit Is provided with a first outdoor heat exchanger located on the windward side and a second outdoor heat exchanger located on the leeward side with respect to the air blown by the outdoor blower, and the first outdoor heat exchanger is provided for the refrigerant flow during heating. The first and second outdoor heat exchangers are connected in series so that the heat exchanger is located on the upstream side, and during heating, based on the inlet temperature or the outdoor temperature of the first outdoor heat exchanger, The gist is that the defrosting control is performed by loosening the diaphragm.

[0012]

In the above structure, first, freezing of the outdoor heat exchanger during heating occurs near the inlet of the second outdoor heat exchanger on the leeward side of the two heat exchangers connected in parallel. easy. Frost is detected at the inlet temperature or the outdoor temperature of the second outdoor heat exchanger, the bypass passage is opened based on the detection result, and high-temperature compressor discharge gas is guided to the second outdoor heat exchanger. , Defrosting is performed properly. Frost detection and defrost control can be sufficiently handled only by the second outdoor heat exchanger on the leeward side. The first outdoor heat exchanger on the windward side has a higher outside air temperature for heat exchange than the second outdoor heat exchanger, and therefore has a high evaporation temperature and is unlikely to freeze. As a result, heating performance can be improved.

Secondly, of the two heat exchangers connected in series, frost formation is detected at the inlet temperature or the outdoor temperature of the first outdoor heat exchanger located upstream of the refrigerant flow during heating.
Based on this detection result, the bypass passage is opened, the high-temperature compressor discharge gas is guided to the first outdoor heat exchanger side, and defrosting is appropriately performed. Since the outdoor heat exchanger is configured to be thermally divided into two parts, frost detection and defrost control are performed on the upstream first side.
Only the outdoor heat exchanger can be used. Also, the first
Since the outdoor heat exchanger is located on the windward side with respect to the air blown by the outdoor blower, the outside air temperature for heat exchange is high and the evaporation temperature is high, so that it is difficult to form frost. As a result, heating performance can be improved.

Thirdly, of the two outdoor heat exchangers connected in parallel, frost formation is detected at the inlet temperature or outdoor temperature of the second outdoor heat exchanger on the leeward side during heating. On the basis of this, the four-way valve is reversed and the high-temperature compressor discharge gas is guided to the second outdoor heat exchanger, so that defrosting is appropriately performed. Frost detection and defrost control can be sufficiently handled only by the second outdoor heat exchanger on the leeward side. The first outdoor heat exchanger on the windward side is the second
Since the outside air temperature for heat exchange is higher than that of the outdoor heat exchanger, the evaporation temperature is high and it is hard to freeze. As a result, heating performance can be improved.

Fourth, among the two outdoor heat exchangers connected in parallel, frost is detected at the inlet temperature or outdoor temperature of the second outdoor heat exchanger on the leeward side during heating, and the detection result is Based on this, the throttle of the expansion device is loosened and the high-temperature high-pressure gas or liquid is directly sent to the second outdoor heat exchanger, and defrosting is appropriately performed. Frost detection and defrost control can be sufficiently handled only by the second outdoor heat exchanger on the leeward side. The first outdoor heat exchanger on the windward side has a higher outside air temperature for heat exchange than the second outdoor heat exchanger, and therefore has a high evaporation temperature and is unlikely to freeze. As a result,
It is possible to improve the heating performance.

Fifth, of the two outdoor heat exchangers connected in series, frost formation is detected at the inlet temperature or outdoor temperature of the first outdoor heat exchanger located upstream of the refrigerant flow during heating. Based on the detection result, the four-way valve is reversed to the refrigerant flow side during cooling, the hot compressor discharge gas is guided to the first and second outdoor heat exchangers, and defrosting is appropriately performed. Frost detection and defrost control can be sufficiently handled only by the first outdoor heat exchanger on the upstream side. Since the first outdoor heat exchanger is located on the windward side of the air blown by the outdoor blower, the temperature of the outside air for heat exchange is high and the evaporation temperature is high, so that frost formation is difficult. As a result,
It is possible to improve the heating performance.

Sixth, of the two outdoor heat exchangers connected in series, frost is detected at the inlet temperature or outdoor temperature of the first outdoor heat exchanger located upstream of the refrigerant flow during heating. The throttle of the throttle device is loosened based on the detection result, and the high-temperature high-pressure gas or liquid is directly sent to the first outdoor heat exchanger, and the defrosting is appropriately performed. Frost detection and defrost control can be sufficiently handled only by the first outdoor heat exchanger on the upstream side. Since the first outdoor heat exchanger is located on the windward side of the air blown by the outdoor blower, the temperature of the outside air for heat exchange is high and the evaporation temperature is high, so that frost formation is difficult. As a result, heating performance can be improved.

[0018]

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

FIG. 1 is a diagram showing a first embodiment of the present invention. In the refrigeration cycle of FIG. 1, the outdoor unit 1 includes a compressor 2, a four-way valve 3, a throttle mechanism 4, a first outdoor heat exchanger 5, a second outdoor heat exchanger 6, an outdoor blower 7, and a first outdoor unit. Heat exchanger inlet two-way valve 8, second outdoor heat exchanger inlet temperature sensor 9, second outdoor heat exchanger outlet temperature sensor 11, outdoor temperature sensor 12, compressor discharge gas to the second outdoor heat exchanger 6, a bypass passage 13 to be bypassed, a defrosting two-way valve 14 connected in the bypass passage 13, a controller for controlling the defrosting two-way valve 14 and the first outdoor heat exchanger inlet two-way valve 8. 15
It is composed of main parts such as. First outdoor heat exchanger 5
Is located on the windward side with respect to the air blown by the outdoor blower 7,
The outdoor heat exchanger 6 is located on the leeward side, and the outdoor heat exchangers 5 and 6 are connected in parallel. In addition, the indoor unit 10
Is composed of an indoor heat exchanger 16, an indoor blower 17, and the like. The refrigerant used in the present refrigeration cycle is close to the single refrigerant of R22 in cycle temperature and pressure, for example, R32 / R.
It is a non-azeotropic mixed refrigerant of 134a = 30: 70. In FIG. 1, the flow of this refrigerant is shown by a solid line during heating and a broken line during cooling.

Next, the operation of the refrigeration cycle configured as described above will be described. First, the heating operation will be described. During normal operation, the first outdoor heat exchanger inlet two-way valve 8 is opened and the defrosting two-way valve 14 is closed. The high-temperature, high-pressure vaporized refrigerant discharged from the compressor 2 in the outdoor unit 1 is
After passing through the four-way valve 3, it is guided to the indoor unit 10 and exchanges heat with the indoor air by the indoor blower 17 while flowing through the indoor heat exchanger 16, thereby releasing heat and condensing it indoors. The condensed and liquefied refrigerant returns to the outdoor unit 1, is throttled by the throttling mechanism 4, is depressurized, and is then ventilated by the outdoor blower 7 by the first and second outdoor heat exchangers 5 and 6 connected in parallel. Heat exchange with and complete the evaporation process. The heated low-pressure vaporized refrigerant again enters the compressor 2 and is discharged as high-temperature, high-pressure vaporized refrigerant, and one cycle of heating is completed. During the heating operation, frost formation is detected by the inlet temperature or the outdoor temperature of the second outdoor heat exchanger 6. If these temperatures are equal to or lower than a predetermined set temperature, it is determined that frost is formed. Defrost
It is performed by closing the first outdoor heat exchanger inlet two-way valve 8 and opening the defrosting two-way valve 14 to bypass the high-temperature compressor discharge gas to the second outdoor heat exchanger 6. The completion of defrosting is judged by looking at the inlet temperature or the outlet temperature of the second outdoor heat exchanger 6. If these temperatures exceed the set temperature, it is determined that the defrosting operation has ended.

Next, the cooling operation will be described. The high-temperature and high-pressure vaporized refrigerant discharged from the compressor 2 in the outdoor unit 1 is
After passing through the four-way valve 3, it is guided to the first and second outdoor heat exchangers 5 and 6 connected in parallel, and is cooled by the outdoor air by the outdoor blower 7 to complete the condensation process. The high-pressure liquid refrigerant is throttled by the throttling mechanism 4 and depressurized. Then, by being guided to the indoor unit 10 and exchanging heat with the indoor air by the indoor blower 17 in the indoor heat exchanger 16, the heat of the indoor air is taken in the evaporation process and cooling is performed. The low-pressure vaporized refrigerant enters the compressor 2 of the outdoor unit 1 and is again discharged as high-temperature, high-pressure vaporized refrigerant, and one cycle during cooling is completed.

The above refrigeration cycle has many advantages as described below. As shown in the Mollier diagram of FIG. 6, when a single refrigerant such as R22 is used (see FIG.
Compared to (a)), when a non-azeotropic mixed refrigerant in the vicinity of R32 / R134a = 30: 70 is used (FIG. 6 (b)), the temperature gradient during the gas-liquid phase change of the refrigerant is large (the isotherm is Leaning). Therefore, in defrosting control during heating, it is easy to freeze near the inlet of the second outdoor heat exchanger 6 on the leeward side, and proper frost detection can be performed by looking at the temperature near the inlet or the outside air temperature. Become. And the judgment of defrosting completion is the second
This can be done by looking at the inlet temperature and the outlet temperature of the outdoor heat exchanger 6. Further, since the outdoor heat exchanger is thermally divided into two parts, only the second outdoor heat exchanger 6 on the leeward side can sufficiently cope with frost detection and defrost control. Compared with the second outdoor heat exchanger 6 on the leeward side, the first outdoor heat exchanger 5 on the leeward side has a higher outside air temperature for heat exchange, and thus has a higher evaporation temperature and is less likely to freeze. As a result, heating performance can be improved.

FIG. 2 shows a second embodiment of the present invention. In the present embodiment, as shown in the refrigeration cycle of FIG. 2, the first outdoor heat exchanger 5 located on the upwind side and the second outdoor heat exchanger located on the downwind side with respect to the air blown by the outdoor blower 7. 6
Are connected in series so that the first outdoor heat exchanger 5 is on the upstream side with respect to the refrigerant flow during heating. 18 is the first
The outdoor heat exchanger inlet temperature sensor, and 19 is a first outdoor heat exchanger outlet temperature sensor. Other configurations are the same as those of the first
It is almost the same as that of the embodiment.

The operation of the refrigeration cycle configured as described above will be described from the heating operation. Compressor 2 in outdoor unit 1
The discharged high-temperature, high-pressure vaporized refrigerant is guided to the indoor unit 10 after passing through the four-way valve 3, and while exchanging heat with the indoor air by the indoor blower 17 while flowing through the indoor heat exchanger 16, It releases heat to and condenses. The condensed and liquefied refrigerant returns to the outdoor unit 1, is throttled by the throttling mechanism 4, is depressurized, and is then connected in series to the first and second outdoor heat exchangers 5, 5.
At 6 the heat is exchanged with the outdoor air by the outdoor blower 7 to complete the evaporation process. The heated low-pressure vaporized refrigerant again enters the compressor 2 and is discharged as high-temperature, high-pressure vaporized refrigerant, and one cycle of heating is completed. During this heating operation,
The detection of frost formation is determined by the inlet temperature or the outdoor temperature of the first outdoor heat exchanger 5. If these temperatures are equal to or lower than a predetermined set temperature, it is determined that frost is formed. Defrosting is a two-way valve for defrosting 1.
4 is opened to bypass the high-temperature compressor discharge gas to the first outdoor heat exchanger 5 side. The completion of defrosting is judged by looking at the inlet temperature or the outlet temperature of the first outdoor heat exchanger 5. If these temperatures exceed the set temperature, it is determined that the defrosting operation has ended.

Next, the cooling operation will be described. The high-temperature and high-pressure vaporized refrigerant discharged from the compressor 2 in the outdoor unit 1 is
After passing through the four-way valve 3, it is guided to the first and second outdoor heat exchangers 5 and 6 connected in series, and is cooled by the outdoor air by the outdoor blower 7 to complete the condensation process. The high-pressure liquid refrigerant is throttled by the throttling mechanism 4 and depressurized. Then, by being guided to the indoor unit 10 and exchanging heat with the indoor air by the indoor blower 17 in the indoor heat exchanger 16, the heat of the indoor air is taken in the evaporation process and cooling is performed. The low-pressure vaporized refrigerant enters the compressor 2 of the outdoor unit 1 and is again discharged as high-temperature, high-pressure vaporized refrigerant, and one cycle during cooling is completed.

The above refrigeration cycle has many advantages as described below. As mentioned above, R32 / R1
When a non-azeotropic mixed refrigerant of 34a = 30: 70 is used, the temperature gradient during the gas-liquid phase change of the refrigerant is large. Therefore, in defrosting control during heating, it is easy to freeze near the inlet of the outdoor heat exchanger, and proper frost detection can be performed by looking at the temperature near the inlet or the outside air temperature. The completion of defrosting can be determined by checking the inlet temperature and the outlet temperature of the first outdoor heat exchanger 5 on the upstream side. Further, since the outdoor heat exchanger is thermally divided into two parts, frost detection and defrosting control can be sufficiently performed only by the first outdoor heat exchanger 5 on the upstream side. Moreover, since the first outdoor heat exchanger 5 on the upstream side is located on the windward side of the air blown by the outdoor blower 7, the outside air temperature for heat exchange is high and the evaporation temperature is high, so that frost formation is difficult. ing. As a result, heating performance can be improved.

FIG. 3 shows a third embodiment of the present invention. The refrigeration cycle of the present embodiment differs from the refrigeration cycle of the first embodiment (FIG. 1) in that the first outdoor heat exchanger inlet two-way valve 8 and the bypass passage 13 are removed, and the first outdoor heat exchange is performed. It has a configuration in which a device outlet two-way valve 20 is added. The other components are almost the same as those in FIG.

In the heating operation of such a refrigeration cycle, the detection of frost formation is judged by the inlet temperature or the outdoor temperature of the second outdoor heat exchanger 6. If these temperatures are equal to or lower than a predetermined set temperature, it is determined that frost is formed. Defrosting is performed by closing the first outdoor heat exchanger outlet two-way valve 20, reversing the four-way valve 3 and bypassing the high-temperature compressor discharge gas to the second outdoor heat exchanger 6. The completion of defrosting is judged by looking at the inlet temperature or the outlet temperature of the second outdoor heat exchanger 6. If these temperatures exceed the set temperature, it is determined that the defrosting operation has ended.

The above-mentioned refrigeration cycle has many advantages as described below. As shown in the Mollier diagram of FIG. 6, when a single refrigerant such as R22 is used (see FIG.
Compared to (a)), when a non-azeotropic mixed refrigerant in the vicinity of R32 / R134a = 30: 70 is used (FIG. 6 (b)), the temperature gradient during the gas-liquid phase change of the refrigerant is large (the isotherm is Leaning). Therefore, in defrosting control during heating, it is easy to freeze near the inlet of the second outdoor heat exchanger 6 on the leeward side, and proper frost detection can be performed by looking at the temperature near the inlet or the outside air temperature. Become. And the judgment of defrosting completion is the second
This can be done by looking at the inlet temperature and the outlet temperature of the outdoor heat exchanger 6. Further, since the outdoor heat exchanger is thermally divided into two parts, only the second outdoor heat exchanger 6 on the leeward side can sufficiently cope with frost detection and defrost control. Compared with the second outdoor heat exchanger 6 on the leeward side, the first outdoor heat exchanger 5 on the leeward side has a higher outside air temperature for heat exchange, and thus has a higher evaporation temperature and is less likely to freeze. As a result, heating performance can be improved.

FIG. 4 shows a fourth embodiment of the present invention. The refrigeration cycle of the present embodiment has a configuration in which the bypass passage 13 is removed from the refrigeration cycle of the first embodiment (FIG. 1).

In the heating operation of such a refrigeration cycle, the detection of frost formation is determined by the inlet temperature or the outdoor temperature of the second outdoor heat exchanger 6. If these temperatures are equal to or lower than a predetermined set temperature, it is determined that frost is formed. Defrosting is performed by closing the first outdoor heat exchanger inlet two-way valve 8, loosening the throttle of the expansion device 4, and sending the hot compressor discharge gas or refrigerant liquid to the second outdoor heat exchanger 6. Be seen. The completion of defrosting is judged by looking at the inlet temperature or the outlet temperature of the second outdoor heat exchanger 6. If these temperatures exceed the set temperature, it is determined that the defrosting operation has ended.

The above-mentioned refrigeration cycle has many advantages as described below. As shown in the Mollier diagram of FIG. 6, when a single refrigerant such as R22 is used (see FIG.
Compared to (a)), when a non-azeotropic mixed refrigerant in the vicinity of R32 / R134a = 30: 70 is used (FIG. 6 (b)), the temperature gradient during the gas-liquid phase change of the refrigerant is large (the isotherm is Leaning). Therefore, in defrosting control during heating, it is easy to freeze near the inlet of the second outdoor heat exchanger 6 on the leeward side, and proper frost detection can be performed by looking at the temperature near the inlet or the outside air temperature. Become. And the judgment of defrosting completion is the second
This can be done by looking at the inlet temperature and the outlet temperature of the outdoor heat exchanger 6. Further, since the outdoor heat exchanger is thermally divided into two parts, only the second outdoor heat exchanger 6 on the leeward side can sufficiently cope with frost detection and defrost control. Compared with the second outdoor heat exchanger 6 on the leeward side, the first outdoor heat exchanger 5 on the leeward side has a higher outside air temperature for heat exchange, and thus has a higher evaporation temperature and is less likely to freeze. As a result, heating performance can be improved.

FIG. 5 shows a fifth embodiment of the present invention. The refrigeration cycle of the present embodiment has a configuration in which the bypass passage 13 is removed from the refrigeration cycle of the second embodiment (FIG. 2).

During the heating operation of such a refrigeration cycle, the detection of frost formation is judged by the inlet temperature or the outdoor temperature of the first outdoor heat exchanger 5. If these temperatures are equal to or lower than a predetermined set temperature, it is determined that frost has formed. Defrosting is performed by reversing the four-way valve 3 and bypassing the high-temperature compressor discharge gas to the first and second outdoor heat exchangers 5 and 6. The completion of defrosting is judged by looking at the inlet temperature or the outlet temperature of the first outdoor heat exchanger 5. If these temperatures exceed the set temperature, it is determined that the defrosting operation has ended.

The above refrigeration cycle has many advantages as described below. As mentioned above, R32 / R1
When a non-azeotropic mixed refrigerant of 34a = 30: 70 is used, the temperature gradient during the gas-liquid phase change of the refrigerant is large. Therefore, in defrosting control during heating, it is easy to freeze near the inlet of the outdoor heat exchanger, and proper frost detection can be performed by looking at the temperature near the inlet or the outside air temperature. The completion of defrosting can be determined by checking the inlet temperature and the outlet temperature of the first outdoor heat exchanger 5 on the upstream side. Further, since the outdoor heat exchanger is thermally divided into two parts, frost detection and defrosting control can be sufficiently performed only by the first outdoor heat exchanger 5 on the upstream side. Moreover, since the first outdoor heat exchanger 5 on the upstream side is located on the windward side of the air blown by the outdoor blower 7, the outside air temperature for heat exchange is high and the evaporation temperature is high, so that frost formation is difficult. ing. As a result, heating performance can be improved.

Next, a sixth embodiment of the present invention will be described.
The structure of the refrigeration cycle is the same as that of the fifth embodiment (FIG. 5).

During the heating operation of such a refrigeration cycle, the detection of frost formation is judged by the inlet temperature or the outdoor temperature of the first outdoor heat exchanger 5. If these temperatures are equal to or lower than a predetermined set temperature, it is determined that frost is formed. The defrosting is performed by loosening the throttle of the expansion device 4 and sending the high-temperature compressor discharge gas or refrigerant liquid to the first outdoor heat exchanger 5 side. The completion of defrosting is judged by looking at the inlet temperature or the outlet temperature of the first outdoor heat exchanger 5. If these temperatures exceed the set temperature, it is determined that the defrosting operation has ended.

The above refrigeration cycle has many advantages as follows. As mentioned above, R32 / R1
When a non-azeotropic mixed refrigerant of 34a = 30: 70 is used, the temperature gradient during the gas-liquid phase change of the refrigerant is large. Therefore, in defrosting control during heating, it is easy to freeze near the inlet of the outdoor heat exchanger, and proper frost detection can be performed by looking at the temperature near the inlet or the outside air temperature. The completion of defrosting can be determined by checking the inlet temperature and the outlet temperature of the first outdoor heat exchanger 5 on the upstream side. Further, since the outdoor heat exchanger is thermally divided into two parts, frost detection and defrosting control can be sufficiently performed only by the first outdoor heat exchanger 5 on the upstream side. Moreover, since the first outdoor heat exchanger 5 on the upstream side is located on the windward side of the air blown by the outdoor blower 7, the outside air temperature for heat exchange is high and the evaporation temperature is high, so that frost formation is difficult. ing. As a result, heating performance can be improved.

The present invention is not limited to the above embodiments, and the refrigerating cycle may have a slightly different structure without departing from the spirit of the claims.

[0040]

As described above, according to the present invention,
First, the outdoor unit has a first outdoor heat exchanger located on the windward side and a second unit located on the leeward side with respect to the air blown by the outdoor blower.
Of the outdoor heat exchanger, the first and second outdoor heat exchangers are connected in parallel, and the second outdoor heat exchanger is connected to a normally closed bypass path for bypassing the compressor discharge gas. Since the defrosting control is performed by opening the bypass passage on the basis of the inlet temperature or the outdoor temperature of the second outdoor heat exchanger during heating, in the refrigeration cycle using the non-azeotropic mixed refrigerant, Frost detection and defrost control can be properly performed. Further, the first outdoor heat exchanger on the windward side is
Since the outside air temperature for heat exchange is higher than that of the second outdoor heat exchanger, the evaporation temperature is high and it is difficult to freeze, so that the heating performance can be improved.

Secondly, the outdoor unit is provided with a first outdoor heat exchanger located on the upwind side and a second outdoor heat exchanger located on the downwind side with respect to the air blown by the outdoor blower, and at the time of heating. The first and second outdoor heat exchangers are connected in series so that the first outdoor heat exchanger is on the upstream side with respect to the refrigerant flow, and the compressor discharge gas is bypassed to the first outdoor heat exchanger. A non-azeotropic mixed refrigerant is used because a normally closed bypass path is connected and the defrost control is performed by opening the bypass path based on the inlet temperature or outdoor temperature of the first outdoor heat exchanger during heating. In the above refrigeration cycle, frost formation detection and defrost control during heating can be properly performed. Further, since the first outdoor heat exchanger is located on the windward side with respect to the air blown by the outdoor blower, the temperature of the outside air to be heat-exchanged is high and the evaporation temperature is high, so that it is difficult to form frost and the heating performance is improved. Can be improved.

Thirdly, the outdoor unit is provided with a first outdoor heat exchanger located on the upwind side and a second outdoor heat exchanger located on the downwind side with respect to the air blown by the outdoor blower. 1 and 2 outdoor heat exchangers are connected in parallel, the four-way valve is reversed based on the inlet temperature or outdoor temperature of the second outdoor heat exchanger during heating, and the compressor is discharged to the second outdoor heat exchanger. Since the gas is guided to perform defrost control, it is possible to appropriately perform frost detection and defrost control during heating in a refrigeration cycle using a non-azeotropic mixed refrigerant. Further, the first outdoor heat exchanger on the windward side has a higher outside air temperature for heat exchange than the second outdoor heat exchanger, and therefore has a high evaporation temperature and is unlikely to freeze, so that the heating performance can be improved.

Fourth, the outdoor unit is provided with a first outdoor heat exchanger located on the upwind side and a second outdoor heat exchanger located on the downwind side with respect to the air blown by the outdoor blower. Since the first and second outdoor heat exchangers are connected in parallel and the defrosting control is performed by loosening the throttle of the expansion device based on the inlet temperature or the outdoor temperature of the second outdoor heat exchanger during heating, In a refrigeration cycle using a non-azeotropic mixed refrigerant,
It is possible to properly perform frost detection and defrost control during heating. Further, the first outdoor heat exchanger on the windward side has a higher outside air temperature for heat exchange than the second outdoor heat exchanger, and therefore has a high evaporation temperature and is unlikely to freeze, so that the heating performance can be improved.

Fifth, the outdoor unit is provided with a first outdoor heat exchanger located on the upwind side and a second outdoor heat exchanger located on the downwind side with respect to the air blown by the outdoor blower, and at the time of heating. The first and second outdoor heat exchangers are connected in series so that the first outdoor heat exchanger is on the upstream side with respect to the refrigerant flow, and the inlet temperature or the outdoor temperature of the first outdoor heat exchanger is changed during heating. Since the four-way valve is configured to reverse the refrigerant flow side during cooling to perform defrost control, the high-temperature compressor discharge gas is guided to the first and second outdoor heat exchangers for non-azeotropic mixing. In a refrigeration cycle that uses a refrigerant, frost formation detection and defrost control during heating can be appropriately performed. In addition, since the first outdoor heat exchanger is located on the windward side of the air blown by the outdoor blower, the outside air temperature for heat exchange is high, and the evaporation temperature is high, so that it is difficult to form frost, and therefore the heating performance is improved. You can

Sixth, the outdoor unit is provided with a first outdoor heat exchanger located on the upwind side and a second outdoor heat exchanger located on the downwind side with respect to the air blown by the outdoor blower, and at the time of heating. The first and second outdoor heat exchangers are connected in series so that the first outdoor heat exchanger is on the upstream side with respect to the refrigerant flow, and the inlet temperature or the outdoor temperature of the first outdoor heat exchanger is changed during heating. Since the defrosting control is performed by loosening the throttle of the expansion device, the frosting detection and the defrosting control during heating can be appropriately performed in the refrigeration cycle using the non-azeotropic mixed refrigerant. Further, since the first outdoor heat exchanger is located on the windward side of the air blown by the outdoor blower, the outside air temperature for heat exchange is high, and the evaporation temperature is high, so frost formation is difficult and the heating performance can be improved. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a refrigeration cycle in a first embodiment of an air conditioner according to the present invention.

FIG. 2 is a diagram showing a refrigeration cycle in a second embodiment of the present invention.

FIG. 3 is a diagram showing a refrigeration cycle in a third embodiment of the present invention.

FIG. 4 is a diagram showing a refrigeration cycle in a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a refrigeration cycle in a fifth embodiment of the present invention.

FIG. 6 is a Mollier diagram for explaining a temperature gradient at the time of gas-liquid phase change when a single refrigerant is used and when a non-azeotropic mixed refrigerant is used.

[Explanation of symbols]

 1 outdoor unit 2 compressor 3 four-way valve 4 throttle mechanism (throttle device) 5 first outdoor heat exchanger 6 second outdoor heat exchanger 7 outdoor blower 8 first outdoor heat exchanger inlet two-way valve 9 second Outdoor heat exchanger inlet temperature sensor 10 indoor unit 11 second outdoor heat exchanger outlet temperature sensor 12 outdoor temperature sensor 13 bypass path 14 defrosting two-way valve 15 controller 16 indoor heat exchanger 18 first outdoor heat Exchanger inlet temperature sensor 19 First outdoor heat exchanger outlet temperature sensor 20 First outdoor heat exchanger outlet two-way valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuji Yamashita 8 Shinsita-cho, Isogo-ku, Yokohama, Kanagawa Pref., Institute of Housing and Space Systems Technology, Toshiba Corporation (72) Koichi Goto, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 2-4, Toshiba Keihin Office

Claims (6)

[Claims] 1. In an air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant, the outdoor unit is located leeward with a first outdoor heat exchanger located upwind with respect to air blown by an outdoor blower. And a second outdoor heat exchanger, the first and second outdoor heat exchangers are connected in parallel, and the second outdoor heat exchanger bypasses the compressor discharge gas. An air conditioner configured to connect the paths and open the bypass path based on the inlet temperature or the outdoor temperature of the second outdoor heat exchanger to perform defrost control during heating. . 2. An air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant, wherein the outdoor unit is located leeward with a first outdoor heat exchanger located upwind with respect to air blown by an outdoor blower. And a second outdoor heat exchanger, and the first and second outdoor heat exchangers are connected in series so that the first outdoor heat exchanger is on the upstream side with respect to the refrigerant flow during heating. , A normally closed bypass passage for bypassing the compressor discharge gas is connected to the first outdoor heat exchanger, and the bypass passage is formed on the basis of the inlet temperature or the outdoor temperature of the first outdoor heat exchanger during heating. An air conditioner characterized by being configured to open and perform defrost control. 3. An air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant and having a four-way valve for setting a refrigerant path during cooling and heating, wherein the outdoor unit is upwind with respect to the air blown by an outdoor blower. And a second outdoor heat exchanger located leeward are provided, and the first and second outdoor heat exchangers are connected in parallel, and the second outdoor heat exchanger is connected during heating. The four-way valve is reversed based on the inlet temperature or the outdoor temperature of the outdoor heat exchanger, and the compressor discharge gas is guided to the second outdoor heat exchanger to perform defrost control. A characteristic air conditioner. 4. An air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant and having a throttle device for restricting the refrigerant flow between the indoor heat exchanger and the outdoor heat exchanger side. A first outdoor heat exchanger located on the windward side and a second outdoor heat exchanger located on the leeward side are provided for the air blown by the outdoor blower, and the first and second outdoor heat exchangers are arranged in parallel. An air conditioner that is connected and configured to loosen a throttle of the expansion device and perform defrosting control based on an inlet temperature or an outdoor temperature of the second outdoor heat exchanger during heating. 5. An air conditioner having a refrigeration cycle using a non-azeotropic mixed refrigerant and having a four-way valve for setting a refrigerant path during cooling and heating, wherein the outdoor unit is upwind with respect to air blown by an outdoor blower. And a second outdoor heat exchanger located leeward, so that the first outdoor heat exchanger is upstream with respect to the refrigerant flow during heating. The first and second outdoor heat exchangers are connected in series, and the four-way valve is inverted to the refrigerant flow side during cooling based on the inlet temperature or the outdoor temperature of the first outdoor heat exchanger during heating. An air conditioner characterized by being configured to perform defrost control. 6. An air conditioner having a refrigeration cycle, which uses a non-azeotropic mixed refrigerant and is provided with a throttle device for narrowing the flow of the refrigerant between the indoor heat exchanger and the outdoor heat exchanger side. The first outdoor heat exchanger located on the windward side and the second outdoor heat exchanger located on the leeward side are provided for the air blown by the outdoor blower, and the first outdoor heat exchanger is provided for the refrigerant flow during heating.
The first and second outdoor heat exchangers are connected in series so that the outdoor heat exchanger of FIG. 1 is on the upstream side, and the throttle is based on the inlet temperature or the outdoor temperature of the first outdoor heat exchanger during heating. An air conditioner characterized by being configured so that defrosting control is performed by loosening a diaphragm of the device.