US20230126980A1

US20230126980A1 - Refrigeration Cycle Apparatus

Info

Publication number: US20230126980A1
Application number: US17/918,189
Authority: US
Inventors: Kenta MURATA
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2020-04-20
Filing date: 2020-04-20
Publication date: 2023-04-27
Also published as: EP4141348A1; WO2021214832A1; EP4141348A4; JPWO2021214832A1

Abstract

A refrigeration cycle apparatus includes a refrigerant circuit and refrigerant. The refrigerant is a zeotropic mixed refrigerant. At least one of the condenser and the evaporator has a first heat exchange unit located windward and a second heat exchange unit located leeward in a first direction in which air flows. Each of the first heat exchange unit and the second heat exchange unit has an inflow passage and an outflow passage for the refrigerant that are located in a plurality of stages arranged in the second direction crossing the first direction. The refrigerant flows out from the outflow passage of the second heat exchange unit into the inflow passage of the first heat exchange unit. The outflow passage of the second heat exchange unit is located in the same stage as the outflow passage of the first heat exchange unit in the second direction.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of International Patent Application No. PCT/JP2020/017058 filed on Apr. 20, 2020, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a refrigeration cycle apparatus.

BACKGROUND

Mixed refrigerants have been taken into consideration as refrigerants each having a low global warming potential (GWP). Among the mixed refrigerants, a zeotropic mixed refrigerant has been used in which refrigerants having different boiling points are mixed. In the case of the zeotropic mixed refrigerant, the temperature of the refrigerant is changed in accordance with a degree of dryness of the refrigerant in a gas-liquid two-phase region. That is, a temperature gradient is generated. In this temperature gradient, the temperature of the refrigerant is decreased as the degree of dryness of the refrigerant is smaller.
For example, Japanese Patent Laying-Open No. 7-269985 (PTL 1) discloses a heat exchanger of an air conditioner using a zeotropic mixed refrigerant. In this heat exchanger, flow passages of heat exchange pipes are located in a plurality of rows arranged on the upstream side and downstream side of air. A refrigerant outlet in the upstream side row and a refrigerant inlet in the downstream side row are located side by side in a direction in which air flows.

PATENT LITERATURE

PTL 1: Japanese Patent Laying-Open No. 7-269985

In the heat exchanger of the air conditioner described in the above publication, at a portion at which the refrigerant outlet in the upstream side row and the refrigerant inlet in the downstream side row are located side by side, a temperature difference between the refrigerant and the air is small, thus resulting in a decreased heat exchange amount.

SUMMARY

The present disclosure has been made to solve the above-described problem and has an object to provide a refrigeration cycle apparatus so as to suppress a decrease in heat exchange amount while using a zeotropic mixed refrigerant having a low global warming potential.
A refrigeration cycle apparatus of the present disclosure comprises a refrigerant circuit and a refrigerant. The refrigerant circuit comprises a compressor, a condenser, a pressure reducing valve, and an evaporator. The refrigerant circulates through the refrigerant circuit in order of a compressor, a condenser, a pressure reducing valve, and an evaporator. The refrigerant is a zeotropic mixed refrigerant. At least one of the condenser and the evaporator comprises a first heat exchange unit located windward and a second heat exchange unit located leeward in a first direction in which air flows. Each of the first heat exchange unit and the second heat exchange unit comprises an inflow passage and an outflow passage for the refrigerant that are located in a plurality of stages arranged in a second direction crossing the first direction. The refrigerant flows out from the outflow passage of the second heat exchange unit into the inflow passage of the first heat exchange unit. The outflow passage of the second heat exchange unit is located in the same stage as the outflow passage of the first heat exchange unit in the second direction.
According to the refrigeration cycle apparatus of the present disclosure, the refrigerant is a zeotropic mixed refrigerant. The outflow passage of the second heat exchanger is located in the same stage as the outflow passage of the first heat exchange unit in the second direction. Therefore, a heat exchange amount can be suppressed from being decreased while using the zeotropic mixed refrigerant having a low global warming potential.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a refrigerant circuit diagram showing a refrigeration cycle apparatus according to a first embodiment.

FIG. 2 is a perspective view schematically showing a configuration of a heat exchanger of the refrigeration cycle apparatus according to the first embodiment.

FIG. 3 is a cross sectional view schematically showing the configuration of the heat exchanger of the refrigeration cycle apparatus according to the first embodiment.

FIG. 4 is a graph showing respective temperatures of refrigerant and air in the heat exchanger of the refrigeration cycle apparatus according to the first embodiment.

FIG. 5 is a cross sectional view schematically showing a configuration of a heat exchanger according to a comparative example for the first embodiment.

FIG. 6 is a graph showing respective temperatures of refrigerant and air in the heat exchanger according to the comparative example for the first embodiment.

FIG. 7 is a perspective view schematically showing a configuration of a heat exchanger of a refrigeration cycle apparatus according to a second embodiment.

FIG. 8 is a cross sectional view schematically showing the configuration of the heat exchanger of the refrigeration cycle apparatus according to the second embodiment.

FIG. 9 is a cross sectional view schematically showing a configuration of a heat exchanger according to a comparative example for the second embodiment.

FIG. 10 is a cross sectional view schematically showing a configuration of a heat exchanger in a modification of the refrigeration cycle apparatus according to the second embodiment.

FIG. 11 is a cross sectional view schematically showing a configuration of a heat exchanger of a refrigeration cycle apparatus according to a third embodiment.

FIG. 12 is a diagram showing positions of a heat exchanger and a fan of a refrigeration cycle apparatus according to a fourth embodiment.

FIG. 13 is a cross sectional view schematically showing a configuration of a heat exchanger of a refrigeration cycle apparatus according to a fifth embodiment.

FIG. 14 is a cross sectional view for illustrating thermal loss in a heat exchanger according to a comparative example for the fifth embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to figures. It should be noted that in the description below, the same or corresponding portions are denoted by the same reference characters, and will not be described repeatedly.

First Embodiment

A configuration of a refrigeration cycle apparatus 100 according to a first embodiment will be described with reference to FIG. 1 . Examples of refrigeration cycle apparatus 100 include an air conditioner, a refrigerator, and the like. In the first embodiment, the air conditioner will be described as an exemplary refrigeration cycle apparatus 100. Refrigeration cycle apparatus 100 includes a refrigerant circuit RC, a refrigerant, a controller CD, and blower apparatuses 6, 7.
Refrigerant circuit RC includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a pressure reducing valve 4, and an indoor heat exchanger 5. Compressor 1, four-way valve 2, outdoor heat exchanger 3, pressure reducing valve 4, and indoor heat exchanger 5 are connected to one another by tubes. Refrigerant circuit RC is configured to circulate the refrigerant. Refrigerant circuit RC is configured to perform a refrigeration cycle in which the refrigerant circulates with the phase of the refrigerant being changed.
Compressor 1, four-way valve 2, outdoor heat exchanger 3, pressure reducing valve 4, controller CD, and blower apparatus 6 are accommodated in outdoor unit 101. Indoor heat exchanger 5 and blower apparatus 7 are accommodated in indoor unit 102.
Refrigerant circuit RC is configured to circulate the refrigerant in the order of compressor 1, four-way valve 2, outdoor heat exchanger (condenser) 3, pressure reducing valve 4, indoor heat exchanger (evaporator) 5, and four-way valve 2 during a cooling operation. Further, refrigerant circuit RC is configured to circulate the refrigerant in the order of compressor 1, four-way valve 2, indoor heat exchanger (condenser) 5, pressure reducing valve 4, outdoor heat exchanger (evaporator) 3, and four-way valve 2 during a heating operation.
The refrigerant flows through refrigerant circuit RC in the order of compressor 1, the condenser, pressure reducing valve 4, and the evaporator. The refrigerant is a zeotropic mixed refrigerant. That is, among mixed refrigerants, the refrigerant is a zeotropic mixed refrigerant in which refrigerants having different boiling points are mixed. The refrigerant is a zeotropic mixed refrigerant having a temperature gradient in which the temperature of the refrigerant is changed in accordance with a degree of dryness of the refrigerant in a gas-liquid two-phase region. Specifically, the refrigerant is a zeotropic mixed refrigerant having a temperature gradient in which the temperature of the refrigerant is decreased as the degree of dryness of the refrigerant is smaller. Examples of the refrigerant include R407C, R454A, and the like.
Controller CD is configured to control each apparatus and the like of refrigeration cycle apparatus 100 by performing calculation, instruction and the like. Controller CD is electrically connected to compressor 1, four-way valve 2, pressure reducing valve 4, blower apparatuses 6, 7, and the like, and is configured to control operations of them.
Compressor 1 is configured to compress the refrigerant. Compressor 1 is configured to compress and discharge the suctioned refrigerant. Compressor 1 may be variable in capacity. Compressor 1 may be variable in capacity by adjusting the rotation speed of compressor 1 based on an instruction from controller CD.
Four-way valve 2 is configured to switch flow of the refrigerant so as to cause the refrigerant compressed by compressor 1 to flow to outdoor heat exchanger 3 or indoor heat exchanger 5. Four-way valve 2 is configured to cause the refrigerant discharged from compressor 1 to flow to outdoor heat exchanger (condenser) 3 during the cooling operation. Four-way valve 2 is configured to cause the refrigerant discharged from compressor 1 to flow to indoor heat exchanger (evaporator) 5 during the heating operation.
Outdoor heat exchanger 3 is configured to exchange heat between the refrigerant flowing inside outdoor heat exchanger 3 and the air flowing outside outdoor heat exchanger 3. Outdoor heat exchanger 3 is configured to function as a condenser to condense the refrigerant during the cooling operation, and function as an evaporator to evaporate the refrigerant during the heating operation. Outdoor heat exchanger 3 is a fin-and-tube type heat exchanger having a plurality of fins and a heat transfer tube extending through the plurality of fins.
Pressure reducing valve 4 is configured to expand the refrigerant condensed by the condenser so as to reduce the pressure of the refrigerant. Pressure reducing valve 4 is configured to reduce the pressure of the refrigerant condensed by outdoor heat exchanger (condenser) 3 during the cooling operation, and to reduce the pressure of the refrigerant condensed by indoor heat exchanger (evaporator) 5 during the heating operation. Pressure reducing valve 4 is, for example, an electromagnetic valve.
Indoor heat exchanger 5 is configured to exchange heat between the refrigerant flowing inside indoor heat exchanger 5 and the air flowing outside indoor heat exchanger 5. Indoor heat exchanger 5 is configured to function as an evaporator to evaporate the refrigerant during the cooling operation, and function as a condenser to condense the refrigerant during the heating operation. Indoor heat exchanger 5 is a fin-and-tube type heat exchanger having a plurality of fins and a heat transfer tube extending through the plurality of fins.
Blower apparatus 6 is configured to blow outdoor air to outdoor heat exchanger 3. That is, blower apparatus 6 is configured to supply air to outdoor heat exchanger 3. Blower apparatus 6 may be configured to adjust an amount of air flowing around outdoor heat exchanger 3 by adjusting the rotation speed of blower apparatus 6 based on an instruction from controller CD, thereby adjusting a heat exchange amount between the refrigerant and the air.
Blower apparatus 7 is configured to blow indoor air to indoor heat exchanger 5. That is, blower apparatus 7 is configured to supply air to indoor heat exchanger 5. Blower apparatus 7 may be configured to adjust an amount of air flowing around indoor heat exchanger 5 by adjusting the rotation speed of blower apparatus 7 based on an instruction from controller CD, thereby adjusting a heat exchange amount between the refrigerant and the air.
Next, an operation of refrigeration cycle apparatus 100 will be described with reference to FIG. 1 . Solid arrows in FIG. 1 indicate flow of the refrigerant during the cooling operation, and broken arrows in FIG. 1 indicate flow of the refrigerant during the heating operation.
Refrigeration cycle apparatus 100 can selectively perform the cooling operation and the heating operation. During the cooling operation, the refrigerant circulates in refrigerant circuit RC in the order of compressor 1, four-way valve 2, outdoor heat exchanger 3, pressure reducing valve 4, indoor heat exchanger 5, and four-way valve 2. During the cooling operation, outdoor heat exchanger 3 functions as a condenser. Heat exchange is performed between the refrigerant flowing through outdoor heat exchanger 3 and the air blown by blower apparatus 6. During the cooling operation, indoor heat exchanger 5 functions as an evaporator. Heat exchange is performed between the refrigerant flowing through indoor heat exchanger 5 and the air blown by blower apparatus 7.
During the heating operation, the refrigerant circulates in refrigerant circuit RC in the order of compressor 1, four-way valve 2, indoor heat exchanger 5, pressure reducing valve 4, outdoor heat exchanger 3, and four-way valve 2. During the heating operation, indoor heat exchanger 5 functions as a condenser. Heat exchange is performed between the refrigerant flowing through indoor heat exchanger 5 and the air blown by blower apparatus 7. During the heating operation, outdoor heat exchanger 3 functions as an evaporator. Heat exchange is performed between the refrigerant flowing through outdoor heat exchanger 3 and the air blown by blower apparatus 6.
Next, a configuration of outdoor heat exchanger 3 functioning as a condenser or an evaporator will be described in detail with reference to FIGS. 2 and 3 . It should be noted that indoor heat exchanger 5 functions as a condenser or an evaporator in the same manner as outdoor heat exchanger 3, and may have the same configuration as that of outdoor heat exchanger 3. In the present embodiment, at least one of outdoor heat exchanger 3 and indoor heat exchanger 5 functioning as a condenser or an evaporator may have the following configuration.
Outdoor heat exchanger 3 has a plurality of fins F and a heat transfer tube P extending through the plurality of fins F. Heat transfer tube P includes a plurality of heat transfer portions P1 and a plurality of connection portions P2. The plurality of heat transfer portions P1 are portions extending through the plurality of fins F. The plurality of heat transfer portions P1 are formed in the form of straight lines. The plurality of connection portions P2 are portions that connect heat transfer portions P1 to each other outside the plurality of fins F. Each of the plurality of connection portions P2 is formed to have a U-shape.
Outdoor heat exchanger 3 has a first heat exchange unit C1 and a second heat exchange unit C2. First heat exchange unit C1 is located windward in a first direction D1 in which air flows. First heat exchange unit C1 is located in a first row in first direction D1. Second heat exchange unit C2 is located leeward in first direction D1. Second heat exchange unit C2 is located in a second row in first direction D1.
Each of first heat exchange unit C1 and second heat exchange unit C2 has an inflow passage IF and an outflow passage OF for the refrigerant that are located in a plurality of stages arranged in a second direction D2 crossing first direction D1. Outflow passage OF of second heat exchange unit C2 is located in the same stage as outflow passage OF of first heat exchange unit C1 in second direction D2. Outflow passage OF of second heat exchange unit C2 is located to overlap with outflow passage OF of first heat exchange unit C1 in first direction D1. In other words, outflow passage OF of second heat exchange unit C2 is located to overlap with outflow passage OF of first heat exchange unit C1 when viewed in first direction D1. In the present embodiment, inflow passage IF of second heat exchange unit C2 is located in the same stage as inflow passage IF of first heat exchange unit C1 in second direction D2. Inflow passage IF of second heat exchange unit C2 is located to overlap with inflow passage IF of first heat exchange unit C1 in first direction D1.
First direction D1 may be orthogonal to second direction D2. First direction D1 may be a horizontal direction. Second direction D2 may be an upward/downward direction (vertical direction). Third direction D3 is a direction in which heat transfer portions P1 extend in the form of straight lines. Third direction D3 may be orthogonal to first direction D1 and second direction D2.
In each of first heat exchange unit C1 and second heat exchange unit C2, the plurality of heat transfer portions P1 are located in the plurality of stages arranged in second direction D2. In the present embodiment, the plurality of heat transfer portions P1 are located in four stages. That is, the plurality of heat transfer portions P1 are located in a first stage S1 to a fourth stage S4. In the present embodiment, inflow passage IF of each of first heat exchange unit C1 and second heat exchange unit C2 is heat transfer portion P1 located in first stage S1. Outflow passage OF of each of first heat exchange unit C1 and second heat exchange unit C2 is heat transfer portion P1 located in fourth stage S4.
In each of first heat exchange unit C1 and second heat exchange unit C2, the plurality of heat transfer portions P1 are connected by connection portions P2 as follows. Heat transfer portion P1 of first stage S1 is connected to heat transfer portion P1 of second stage S2 on the back side by connection portion P2. Heat transfer portion P1 of second stage S2 is connected to heat transfer portion P1 of third stage S3 on the front side by connection portion P2. Heat transfer portion P1 of third stage S3 is connected to heat transfer portion P1 of fourth stage S4 on the back side by connection portion P2. Heat transfer portion P1 of first stage S1 of first heat exchange unit C1 is connected to heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2 on the front side by connection portion P2.
Next, flows of the refrigerant and the air in outdoor heat exchanger 3 will be described with reference to FIGS. 2 and 3 .
The refrigerant flows into second heat exchange unit C2 via inflow passage IF, which is heat transfer portion P1 of first stage S1 of second heat exchange unit C2. The refrigerant flows from inflow passage IF, which is heat transfer portion P1 of first stage S1 of second heat exchange unit C2, to outflow passage OF, which is heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2. Thereafter, the refrigerant flows from outflow passage OF of second heat exchange unit C2 to inflow passage IF of first heat exchange unit C1. The refrigerant flows into first heat exchange unit C1 via inflow passage IF, which is heat transfer portion P1 of first stage S1 of first heat exchange unit C1. The refrigerant flows from inflow passage IF, which is heat transfer portion P1 of first stage S1 of first heat exchange unit C1, to outflow passage OF, which is heat transfer portion P1 of fourth stage S4 of first heat exchange unit C1. Thereafter, the refrigerant flows out from first heat exchange unit C1. The refrigerant flows through first heat exchange unit C1 and second heat exchange unit C2 in the form of an inversed N-shape.
The refrigerant flows from second heat exchange unit C2 toward first heat exchange unit C1. The air flows from first heat exchange unit C1 toward second heat exchange unit C2. Therefore, the flow of the refrigerant flowing through second heat exchange unit C2 and first heat exchange unit C1 is a counter flow with respect to the flow of the air flowing through first heat exchange unit C1 and second heat exchange unit C2.
Temperatures of the refrigerant and the air in outdoor heat exchanger 3 will be described with reference to FIGS. 3 and 4 . Each of solid arrows in FIG. 4 indicates a temperature of the refrigerant, and each of broken arrows in FIG. 4 indicates a temperature of the air. In FIG. 4 , each of two-headed arrows indicate a temperature difference between the refrigerant and the air.
FIG. 4 (a) shows the temperatures of the refrigerant and the air at heat transfer portion P1 of first stage S1 of each of the first heat exchange unit and the second heat exchange unit. FIG. 4 (b) shows the temperatures of the refrigerant and the air at heat transfer portion P1 of fourth stage S4 of each of the first heat exchange unit and the second heat exchange unit.
As shown in FIG. 4 (a), a temperature difference ΔT1 between the refrigerant and the air at heat transfer portion P1 of first stage S1 of first heat exchange unit C1 and a temperature difference ΔT2 between the refrigerant and the air at heat transfer portion P1 of first stage S1 of second heat exchange unit C2 are secured. As shown in FIG. 4 (b), a temperature difference ΔT3 between the refrigerant and the air at heat transfer portion P1 of first stage S1 in first heat exchange unit C1 and a temperature difference ΔT4 between the refrigerant and the air at heat transfer portion P1 of fourth stage S4 in second heat exchange unit C2 are secured. It should be noted that a temperature Ta of suction air is constant.
Next, functions and effects of refrigeration cycle apparatus 100 according to the first embodiment will be described in comparison with a comparative example.
Referring to FIGS. 5 and 6 , the flow of the refrigerant flowing through first heat exchange unit C1 and second heat exchange unit C2 in outdoor heat exchanger 3 of the comparative example for the first embodiment is different from the flow of the refrigerant flowing through first heat exchange unit C1 and second heat exchange unit C2 in outdoor heat exchanger 3 of refrigeration cycle apparatus 100 according to the first embodiment. FIG. 6 (a) shows temperatures of the refrigerant and the air at heat transfer portion P1 of first stage S1 of each of first heat exchange unit C1 and second heat exchange unit C2. FIG. 6 (b) shows temperatures of the refrigerant and the air at heat transfer portion P1 of fourth stage S4 of each of first heat exchange unit C1 and second heat exchange unit C2.
In outdoor heat exchanger 3 of the comparative example for the first embodiment, inflow passage IF of second heat exchange unit C2 is heat transfer portion P1 located in first stage S1. Outflow passage OF of second heat exchange unit C2 is heat transfer portion P1 located in fourth stage S4. Inflow passage IF of first heat exchange unit C1 is heat transfer portion P1 located in fourth stage S4. Outflow passage OF of first heat exchange unit C1 is heat transfer portion P1 located in first stage S1.
In outdoor heat exchanger 3 of the comparative example for the first embodiment, the refrigerant flows into second heat exchange unit C2 via inflow passage IF, which is heat transfer portion P1 of first stage S1 of second heat exchange unit C2. The refrigerant flows from inflow passage IF, which is heat transfer portion P1 of first stage S1 of second heat exchange unit C2, to outflow passage OF, which is heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2. Thereafter, the refrigerant flows into first heat exchange unit C1 via inflow passage IF, which is heat transfer portion P1 of the fourth stage of first heat exchange unit C1. In first heat exchange unit C1, the refrigerant flows from inflow passage IF, which is heat transfer portion P1 of fourth stage S4, to outflow passage OF, which is heat transfer portion P1 of first stage S1. The refrigerant flows through first heat exchange unit C1 and second heat exchange unit C2 in the form of a U-shape.
In outdoor heat exchanger 3 of the comparative example for the first embodiment, a temperature difference ΔT4 between the refrigerant and the air is small at heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2. This is due to the following factor. At heat transfer portion P1 of fourth stage S4 of first heat exchange unit C1, a temperature difference ΔT3 between the refrigerant and the air is large, so that a heat exchange amount is large. Accordingly, the temperature of the blown air from first heat exchange unit C1 is increased. Since the temperature of the blown air from first heat exchange unit C1 is the temperature of the suctioned air in second heat exchange unit C2, a temperature difference is small between the temperature of the suctioned air in second heat exchange unit C2 and the refrigerant. As a result, the heat exchange amount is decreased in outflow passage OF, which is heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2.
On the other hand, according to refrigeration cycle apparatus 100 of the first embodiment, referring to FIGS. 2 and 3 , outflow passage OF of second heat exchange unit C2 is located in the same stage as outflow passage OF of first heat exchange unit C1 in second direction D2. Therefore, temperature difference ΔT4 between the refrigerant and the air is small in outflow passage OF of second heat exchange unit C2. This is due to the following factor. At heat transfer portion P1 of fourth stage S4 of first heat exchange unit C1, temperature difference ΔT3 between the refrigerant and the air is small, so that a heat exchange amount is small. Therefore, the temperature of the blown air from first heat exchange unit C1 is suppressed from being increased. Since the temperature of the blown air from first heat exchange unit C1 is the temperature of the suctioned air in second heat exchange unit C2, the temperature difference is large between the temperature of the suctioned air in second heat exchange unit C2 and the refrigerant. Therefore, temperature difference ΔT between the refrigerant and the air is secured. As a result, the heat exchange amount in outflow passage OF of second heat exchange unit C2 is suppressed from being decreased. This leads to improved heat exchanger performance in outflow passage OF of second heat exchange unit C2.
In refrigeration cycle apparatus 100 according to the first embodiment, the refrigerant is a zeotropic mixed refrigerant. Therefore, according to refrigeration cycle apparatus 100 of the first embodiment, the heat exchange amount can be suppressed from being decreased while using the zeotropic mixed refrigerant having a low global warming potential.

Second Embodiment

A refrigeration cycle apparatus 100 according to a second embodiment has the same configuration, functions, and effects as those of refrigeration cycle apparatus 100 according to the first embodiment unless otherwise stated particularly.
The configuration of outdoor heat exchanger 3 in refrigeration cycle apparatus 100 according to the second embodiment will be described with reference to FIGS. 7 and 8 .
In the second embodiment, outdoor heat exchanger 3 has two paths through which the refrigerant flows. That is, outdoor heat exchanger 3 has a first path PA and a second path PB. It should be noted that outdoor heat exchanger 3 may have two or more paths.
Outdoor heat exchanger 3 has a first heat exchange region HF1 and a second heat exchange region HF2 located in second direction D2. First heat exchange region HF1 and second heat exchange region HF2 are located adjacent to each other in second direction D2. First heat exchange region HF1 has a first path PA. Second heat exchange region HF2 has a second path PB. First path PA and second path PB are configured such that the refrigerant flowing through first path PA and the refrigerant flowing through second path PB flow in parallel with each other. First path PA and second path PB are located line-symmetrically with respect to each other in second direction D2.
Each of first heat exchange region HF1 and second heat exchange region HF2 has an inflow passage IF and an outflow passage OF of each of first heat exchange unit C1 and second heat exchange unit C2. In each of first heat exchange region HF1 and second heat exchange region HF2, outflow passage OF of second heat exchange unit C2 is located in the same stage as outflow passage OF of first heat exchange unit C1 in second direction D2.
Each of first heat exchange region HF1 and second heat exchange region HF2 has first heat exchange unit C1 and second heat exchange unit C2. In the present embodiment, in each of first heat exchange region HF1 and second heat exchange region HF2, the plurality of heat transfer portions P1 are located in first stage S1 to fourth stage S4.
In the present embodiment, in first heat exchange region HF1, inflow passage IF of each of first heat exchange unit C1 and second heat exchange unit C2 is heat transfer portion P1 located in first stage S1. Outflow passage OF of each of first heat exchange unit C1 and second heat exchange unit C2 is heat transfer portion P1 located in fourth stage S4.
In the present embodiment, in second heat exchange region HF2, inflow passage IF of each of first heat exchange unit C1 and second heat exchange unit C2 is heat transfer portion P1 located in fourth stage S4. Outflow passage OF of each of first heat exchange unit C1 and second heat exchange unit C2 is heat transfer portion P1 located in first stage S1.
In first heat exchange region HF1, in each of first heat exchange unit C1 and second heat exchange unit C2, the plurality of heat transfer portions P1 are connected by connection portions P2 as follows. Heat transfer portion P1 of first stage S1 is connected to heat transfer portion P1 of second stage S2 on the back side by connection portion P2. Heat transfer portion P1 of second stage S2 is connected to heat transfer portion P1 of third stage S3 on the front side by connection portion P2. Heat transfer portion P1 of third stage S3 is connected to heat transfer portion P1 of fourth stage S4 on the back side by connection portion P2. Heat transfer portion P1 of first stage S1 of first heat exchange unit C1 is connected to heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2 on the front side by connection portion P2.
In second heat exchange region HF2, in each of first heat exchange unit C1 and second heat exchange unit C2, the plurality of heat transfer portions P1 are connected by connection portions P2 as follows. Heat transfer portion P1 of fourth stage S4 is connected to heat transfer portion P1 of third stage S3 on the back side by connection portion P2. Heat transfer portion P1 of third stage S3 is connected to heat transfer portion P1 of second stage S2 on the front side by connection portion P2. Heat transfer portion P1 of second stage S2 is connected to heat transfer portion P1 of first stage S1 on the back side by connection portion P2. Heat transfer portion P1 of fourth stage S4 of first heat exchange unit C1 is connected to heat transfer portion P1 of first stage S1 of second heat exchange unit C2 on the front side by connection portion P2.
As indicated by a region A1 in FIG. 8 , inflow passages IF of first heat exchange unit C1 in first heat exchange region HF1 and second heat exchange region HF2 are located adjacent to each other in second direction D2. In the present embodiment, inflow passages IF of first heat exchange unit C1 in first heat exchange region HF1 and second heat exchange region HF2 are located in stages adjacent to each other.
Next, flows of the refrigerant and the air in outdoor heat exchanger 3 will be described with reference to FIGS. 7 and 8 .
In first heat exchange region HF1, the refrigerant flows into second heat exchange unit C2 via inflow passage IF, which is heat transfer portion P1 of first stage S1 of second heat exchange unit C2. The refrigerant flows from inflow passage IF, which is heat transfer portion P1 of first stage S1 of second heat exchange unit C2, to outflow passage OF, which is heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2. Thereafter, the refrigerant flows from outflow passage OF of second heat exchange unit C2 to inflow passage IF of first heat exchange unit C1. The refrigerant flows into first heat exchange unit C1 via inflow passage IF, which is heat transfer portion P1 of first stage S1 of first heat exchange unit C1. The refrigerant flows from inflow passage IF, which is heat transfer portion P1 of first stage S1 of first heat exchange unit C1, to outflow passage OF, which is heat transfer portion P1 of fourth stage S4 of first heat exchange unit C1. Thereafter, the refrigerant flows out from first heat exchange unit C1. The refrigerant flows through first heat exchange unit C1 and second heat exchange unit C2 in the form of an inversed N-shape.
In second heat exchange region HF2, the refrigerant flows into second heat exchange unit C2 via inflow passage IF, which is heat transfer portion P1 of fourth stage S4 of second heat exchange unit C2. In second heat exchange unit C2, the refrigerant flows from inflow passage IF, which is heat transfer portion P1 of fourth stage S4, to outflow passage OF, which is heat transfer portion P1 of first stage S1. Thereafter, the refrigerant flows from outflow passage OF of second heat exchange unit C2 to inflow passage IF of first heat exchange unit C1. The refrigerant flows into first heat exchange unit C1 via inflow passage IF, which is heat transfer portion P1 of fourth stage S4 of first heat exchange unit C1. In first heat exchange unit C1, the refrigerant flows from inflow passage IF, which is heat transfer portion P1 of fourth stage S4, to outflow passage OF, which is heat transfer portion P1 of first stage S1. Thereafter, the refrigerant flows out from first heat exchange unit C1. The refrigerant flows through first heat exchange unit C1 and second heat exchange unit C2 in the form of an N-shape.
In each of first heat exchange region HF1 and second heat exchange region HF2, the refrigerant flows from second heat exchange unit C2 toward first heat exchange unit C1. The air flows from first heat exchange unit C1 toward second heat exchange unit C2. Therefore, the flow of the refrigerant flowing through second heat exchange unit C2 and first heat exchange unit C1 is a counter flow with respect to the flow of the air flowing through first heat exchange unit C1 and second heat exchange unit C2.
Next, functions and effects of refrigeration cycle apparatus 100 according to the second embodiment will be described in comparison with a comparative example.
Referring to FIG. 9 , the flow of the refrigerant flowing through first heat exchange unit C1 and second heat exchange unit C2 in outdoor heat exchanger 3 of the comparative example for the second embodiment is different from the flow of the refrigerant flowing through first heat exchange unit C1 and second heat exchange unit C2 in outdoor heat exchanger 3 of refrigeration cycle apparatus 100 according to the second embodiment.
Referring to FIG. 9 , in outdoor heat exchanger 3 of the comparative example for the second embodiment, each of first path PA and second path PB is located in the form of an inverted N-shape. In other words, first path PA and second path PB are not located line-symmetrically with respect to each other in second direction D2. As indicated by a region A1 in FIG. 9 , inflow passage IF of first heat exchange unit C1 in first heat exchange region HF1 is located adjacent to outflow passage OF of first heat exchange unit C1 in second heat exchange region HF2 in second direction D2. Due to heat conduction by the plurality of fins F, heat exchange is performed between the refrigerant flowing through inflow passage IF of first heat exchange unit C1 in first heat exchange region HF1 and the refrigerant flowing through outflow passage OF of first heat exchange unit C1 in second heat exchange region HF2. This leads to occurrence of thermal loss between first path PA and second path PB.
On the other hand, according to the refrigeration cycle apparatus of the second embodiment, referring to FIGS. 7 and 8 , inflow passages IF of first heat exchange unit C1 in first heat exchange region HF1 and second heat exchange region HF2 are located adjacent to each other in second direction D2. Therefore, a temperature difference can be small between the refrigerant flowing through inflow passage IF of first heat exchange unit C1 in first heat exchange region HF1 and the refrigerant flowing through inflow passage IF of first heat exchange unit C1 in second heat exchange region HF2. Therefore, thermal loss between first path PA and second path PB can be small.
Next, a modification of refrigeration cycle apparatus 100 according to the second embodiment will be described with reference to FIG. 10 .
In the modification of refrigeration cycle apparatus 100 according to the second embodiment, the number of stages in first heat exchange region HF1 is different from the number of stages in second heat exchange region HF2. Further, in each of first heat exchange region HF1 and second heat exchange region HF2, the number of stages of first heat exchange unit C1 is different from the number of stages of second heat exchange unit C2. First path PA and second path PB are not located line-symmetrically with respect to each other in second direction D2.
In each of first heat exchange region HF1 and second heat exchange region HF2, inflow passage IF of second heat exchange unit C2 is located in a stage different from inflow passage IF of first heat exchange unit C1 in second direction D2. Inflow passage IF of second heat exchange unit C2 is preferably located at a stage displaced by two stages from inflow passage IF of first heat exchange unit C1.
In first heat exchange region HF1, the plurality of heat transfer portions P1 are located in first stage S1 to seventh stage S7. In first heat exchange region HF1, inflow passage IF of second heat exchange unit C2 is heat transfer portion P1 located in first stage S1. Outflow passage OF of second heat exchange unit C2 is heat transfer portion P1 located in seventh stage S7. Inflow passage IF of first heat exchange unit C1 is heat transfer portion P1 located in third stage S3. Outflow passage OF of first heat exchange unit C1 is heat transfer portion P1 located in seventh stage S7.
In second heat exchange region HF2, the plurality of heat transfer portions P1 are located in first stage S1 to fifth stage S5. In second heat exchange region HF2, inflow passage IF of second heat exchange unit C2 is heat transfer portion P1 located in third stage S3. Outflow passage OF of second heat exchange unit C2 is heat transfer portion P1 located in first stage S1. Inflow passage IF of first heat exchange unit C1 is heat transfer portion P1 located in fifth stage S5. Outflow passage OF of first heat exchange unit C1 is heat transfer portion P1 located in first stage S1.
According to the modification of refrigeration cycle apparatus 100 of the second embodiment, in each of first heat exchange region HF1 and second heat exchange region HF2, inflow passage IF of second heat exchange unit C2 is located in a stage different from inflow passage IF of first heat exchange unit C1 in second direction D2. Therefore, a degree of freedom of design can be improved.

Third Embodiment

A refrigeration cycle apparatus 100 according to a third embodiment has the same configuration, functions, and effects as those of refrigeration cycle apparatus 100 according to the first embodiment unless otherwise stated particularly.
The configuration of outdoor heat exchanger 3 in refrigeration cycle apparatus 100 according to the third embodiment will be described with reference to FIG. 11 .
In the third embodiment, in each of first heat exchange unit C1 and second heat exchange unit C2, the inner diameters of the plurality of heat transfer portions P1 are different for each stage. In each of first heat exchange unit C1 and second heat exchange unit C2, the inner diameters of heat transfer portions P1 are smaller in the order of first stage S1 to fourth stage S4. In each of first heat exchange unit C1 and second heat exchange unit C2, inflow passage IF has an inner diameter larger than an inner diameter of outflow passage OF.
Next, functions and effects of refrigeration cycle apparatus 100 according to the third embodiment will be described.
According to refrigeration cycle apparatus 100 of the third embodiment, in each of first heat exchange unit C1 and second heat exchange unit C2, inflow passage IF has an inner diameter larger than that of outflow passage OF. In each of first heat exchange unit C1 and second heat exchange unit C2, the temperature of the refrigerant in inflow passage IF is higher than the temperature of the refrigerant in outflow passage OF. Therefore, a temperature difference between the refrigerant and the air is large in inflow passage IF, thus resulting in a large heat exchange amount. On the other hand, a temperature difference between the refrigerant and the air is small in outflow passage OF, thus resulting in a small heat exchange amount. Since inflow passage IF has an inner diameter larger than that of outflow passage OF, heat exchange performance can be improved.

Fourth Embodiment

A refrigeration cycle apparatus 100 according to a fourth embodiment has the same configuration, functions, and effects as those of refrigeration cycle apparatus 100 according to the second embodiment unless otherwise stated particularly.
The configuration of outdoor heat exchanger 3 in refrigeration cycle apparatus 100 according to the fourth embodiment will be described with reference to FIG. 12 .
In the fourth embodiment, blower apparatus 6 includes: a fan 6 a having a tip and a root; a boss 6 b to which the root of fan 6 a is fixed; and a motor 6 c to which boss 6 b is rotatably connected. Blower apparatus 6 is, for example, a propeller fan.
Outflow passage OF of each of first heat exchange unit C1 and second heat exchange unit C2 in first heat exchange region HF1 are located to overlap with the tip of fan 6 a in first direction D1. In other words, outflow passages OF of first heat exchange unit C1 and second heat exchange unit C2 in first heat exchange region HF1 are located to overlap with the tip of fan 6 a when viewed in first direction D1. Outflow passages OF of first heat exchange unit C1 and second heat exchange unit C2 in second heat exchange region HF2 are located to overlap with boss 6 b and motor 6 c in first direction D1.
Inflow passages IF of first heat exchange unit C1 and second heat exchange unit C2 in each of first heat exchange region HF1 and second heat exchange region HF2 are located to overlap with the center between the tip and the root of fan 6 a in first direction D1. For example, the center of fan 6 a is a portion that sandwiches a middle between the tip and root of fan 6 a and that falls within a range of 40% or more and 60% or less of a distance between the tip and root of fan 6 a in second direction D2.
Next, a wind speed distribution of wind generated by blower apparatus 6 will be described. The wind speed distribution is an average wind speed in a direction (stacking direction) of the stack of the fins. Since each of fan 6 a and boss 6 b has a substantially circular shape, when wind speeds are integrated in the direction of the stack of the fins, a wind speed at tip (outer edge portion) L1 of fan 6 a is smaller than a wind speed at center (central portion) L2 of fan 6 a. A wind speed in a central portion L3 of blower apparatus 6 in which boss 6 b and motor 6 c are located is lower than a wind speed at center (central portion) L2 of fan 6 a. That is, the wind speed at center (central portion) L2 of fan 6 a is larger than each of the wind speeds at tip (outer edge portion) L1 of fan 6 a and central portion L3 of blower apparatus 6.
Next, functions and effects of refrigeration cycle apparatus 100 according to the fourth embodiment will be described.
According to refrigeration cycle apparatus 100 of the fourth embodiment, inflow passages IF of first heat exchange unit C1 and second heat exchange unit C2 in each of first heat exchange region HF1 and second heat exchange region HF2 are located to overlap with the center between the tip and the root of fan 6 a in first direction D1. Therefore, inflow passages IF of first heat exchange unit C1 and second heat exchange unit C2 can be located to overlap with the center of fan 6 a having a large wind speed (air volume). Therefore, a temperature of blown air can be made low.

Fifth Embodiment

A refrigeration cycle apparatus 100 according to a fifth embodiment has the same configuration, functions, and effects as those of refrigeration cycle apparatus 100 according to the second embodiment unless otherwise stated particularly.
The configuration of outdoor heat exchanger 3 in refrigeration cycle apparatus 100 according to the fifth embodiment will be described with reference to FIG. 13 .
In the fifth embodiment, outdoor heat exchanger 3 further includes a sub-cool line SCL connected to outflow passage OF of first heat exchange unit C1 in each of first heat exchange region HF1 and second heat exchange region HF2. Sub-cool line SCL is configured to cool the refrigerant into a super-cooling state. Sub-cool line SCL is located adjacent to outflow passage OF of first heat exchange unit C1 in first heat exchange region HF1 in second direction D2.
In the fifth embodiment, outdoor heat exchanger 3 has two pairs of first heat exchange regions HF1 and second heat exchange regions HF2. A first set ST1 of first heat exchange region HF1 and second heat exchange region HF2 and a second set ST2 of first heat exchange region HF1 and second heat exchange region HF2 are located in second direction D2. In each of first set ST1 of first heat exchange region HF1 and second heat exchange region HF2 and second set ST2 of first heat exchange region HF1 and second heat exchange region HF2, sub-cool line SCL is located opposite to second heat exchange region HF2 with respect to first heat exchange region HF1 in second direction D2.
Each of first set ST1 of first heat exchange region HF1 and second heat exchange region HF2 and second set ST2 of first heat exchange region HF1 and second heat exchange region HF2 has a portion R1 at which the temperature of the refrigerant is high and a portion R2 at which the temperature of the refrigerant is low. Sub-cool line SCL of second set ST2 of first heat exchange region HF1 and second heat exchange region HF2 is located to be interposed between portions R2 at each of which the temperature of the refrigerant is low.
Next, functions and effects of refrigeration cycle apparatus 100 according to the fifth embodiment will be described in comparison with a comparative example.
Referring to FIG. 14 , in a comparative example for the fifth embodiment, each of first path PA in first heat exchange region HF1 and second path PB in second heat exchange region HF2 is formed to have a U-shape. Sub-cool line SCL is located adjacent to inflow passage IF of first heat exchange unit C1 in first heat exchange region HF1 in second direction D2. Therefore, a temperature difference in the refrigerant is large between first path PA and sub-cool line SCL. This leads to large thermal loss between first path PA and sub-cool line SCL.
On the other hand, in refrigeration cycle apparatus 100 according to the fifth embodiment, sub-cool line SCL is located adjacent to outflow passage OF of first heat exchange unit C1 in first heat exchange region HF1 in second direction D2.
Therefore, a temperature difference in the refrigerant is small between outflow passage OF of first heat exchange unit C1 in first heat exchange region HF1 and sub-cool line SCL. This leads to small thermal loss between first path PA and sub-cool line SCL. Therefore, a heat exchange amount in sub-cool line SCL can be suppressed from being decreased.
The above-described embodiments may be combined as appropriate.
The embodiments disclosed herein are illustrative and non-restrictive in any respect. The scope of the present disclosure is defined by the terms of the claims, rather than the embodiments described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Claims

1. A refrigeration cycle apparatus comprising:

a refrigerant circuit comprising a compressor, a condenser, a pressure reducing valve, and an evaporator; and

refrigerant circulating through the refrigerant circuit in order of the compressor, the condenser, the pressure reducing valve, and the evaporator, wherein

the refrigerant is a zeotropic mixed refrigerant,

at least one of the condenser and the evaporator comprises a first heat exchange unit located windward and a second heat exchange unit located leeward in a first direction in which air flows,

each of the first heat exchange unit and the second heat exchange unit comprises an inflow passage and an outflow passage for the refrigerant that are located in a plurality of stages arranged in a second direction crossing the first direction,

the refrigerant flows out from the outflow passage of the second heat exchange unit into the inflow passage of the first heat exchange unit, and

the outflow passage of the second heat exchange unit is located in the same stage as the outflow passage of the first heat exchange unit in the second direction,

wherein

at least one of the condenser and the evaporator has a first heat exchange region and a second heat exchange region located in the second direction,

each of the first heat exchange region and the second heat exchange region has the inflow passage and the outflow passage of each of the first heat exchange unit and the second heat exchange unit,

in each of the first heat exchange region and the second heat exchange region, the refrigerant flows out from the outflow passage of the second heat exchange unit into the inflow passage of the first heat exchange unit,

in each of the first heat exchange region and the second heat exchange region, the outflow passage of the second heat exchange unit is located in the same stage as the outflow passage of the first heat exchange unit in the second direction, and

the inflow passages of the first heat exchange unit in the first heat exchange region and the second heat exchange region are located adjacent to each other in the second direction.

2. The refrigeration cycle apparatus according to claim 1, wherein in each of the first heat exchange unit and the second heat exchange unit, the inflow passage has an inner diameter larger than an inner diameter of the outflow passage.

3. (canceled)

4. The refrigeration cycle apparatus according to claim 1, wherein in each of the first heat exchange region and the second heat exchange region, the inflow passage of the second heat exchange unit is located in a stage different from the inflow passage of the first heat exchange unit in the second direction.

5. The refrigeration cycle apparatus according to claim 1, further comprising a blower apparatus, wherein

the blower apparatus comprises a fan having a tip and a root, a boss to which the root of the fan is fixed, and a motor to which the boss is rotatably connected,

the outflow passage of each of the first heat exchange unit and the second heat exchange unit in the first heat exchange region is located to overlap with the tip of the fan in the first direction,

the outflow passage of each of the first heat exchange unit and the second heat exchange unit in the second heat exchange region is located to overlap with the boss and the motor in the first direction, and

the inflow passage of each of the first heat exchange unit and the second heat exchange unit in each of the first heat exchange region and the second heat exchange region are located to overlap with a center between the tip and the root of the fan in the first direction.

6. The refrigeration cycle apparatus according to claim 1, wherein

at least one of the condenser and the evaporator further comprises a sub-cool line connected to the outflow passage of the first heat exchange unit in each of the first heat exchange region and the second heat exchange region, and

the sub-cool line is located adjacent to the outflow passage of the first heat exchange unit in the first heat exchange region in the second direction.