GB2557523A

GB2557523A - Air conditioner and outdoor unit for air conditioner

Info

Publication number: GB2557523A
Application number: GB1804425.5A
Authority: GB
Inventors: Tamura Naomichi; Aoyama Yutaka
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2015-10-27
Filing date: 2015-10-27
Publication date: 2018-06-20
Anticipated expiration: 2035-10-27
Also published as: JP6608946B2; GB201804425D0; WO2017072866A1; GB2557523B; JPWO2017072866A1

Abstract

An outdoor unit is configured so that: the side surfaces on the outer contours are formed using a plurality of panels provided with an air-suction port through which air from outside the outdoor unit is drawn in, at least one of the plurality of panels being a service panel; and a heat-source-side heat exchanger is divided, in plurality, into a first heat-source-side heat exchanger that is provided along a side surface including the service panel and a second heat-source-side heat exchanger that is provided along a side surface different from the side surface including the service panel. In the first heat-source-side heat exchanger, the channel of the coolant lies parallel to the air flow during air-warming operation. According to the present invention, it is possible to suppress splashing of drain water on the service panel provided in the casing of the outdoor unit, and to prevent the drain water from freezing.

Description

(56) Documents Cited:

WO 2006/003860 A1 JP 2001021284 A

JP 2013007558 A US 20090084131 A1 (86) International Application Data:

PCT/JP2015/080301 Ja 27.10.2015 (87) International Publication Data:

WO2017/072866 Ja 04.05.2017 (58) Field of Search:

INT CL F24F

Other: Jitsuyo Shinan Koho 1922-1996; Jitsuyo Shinan Toroku Koho 1996-2016; Kokai Jitsuyo Shinan Koho 1971-2016; Toroku Jitsuyo Shinan Koho 1994-2016 (71) Applicant(s):

Mitsubishi Electric Corporation (Incorporated in Japan)

7-3, Marunouchi 2-chome, Chiyoda-ku, Tokyo 100-8310, Japan (72) Inventor(s):

Naomichi Tamura Yutaka Aoyama (74) Agent and/or Address for Service:

Mewburn Ellis LLP

City Tower, 40 Basinghall Street, LONDON, Greater London, EC2V 5DE, United Kingdom (54) Title of the Invention: Air conditioner and outdoor unit for air conditioner Abstract Title: Air conditioner and outdoor unit for air conditioner (57) An outdoor unit is configured so that: the side surfaces on the outer contours are formed using a plurality of panels provided with an air-suction port through which air from outside the outdoor unit is drawn in, at least one of the plurality of panels being a service panel; and a heatsource-side heat exchanger is divided, in plurality, into a first heat-source-side heat exchanger that is provided along a side surface including the service panel and a second heat-source-side heat exchanger that is provided along a side surface different from the side surface including the service panel. In the first heat-source-side heat exchanger, the channel of the coolant lies parallel to the air flow during air-warming operation. According to the present invention, it is possible to suppress splashing of drain water on the service panel provided in the casing of the outdoor unit, and to prevent the drain water from freezing.

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DESCRIPTION

Title of Invention

AIR-CONDITIONING APPARATUS AND OUTDOOR UNIT FOR AIR-CONDITIONING

APPARATUS

Technical Field [0001]

The present invention relates to an air-conditioning apparatus, and an outdoor unit for an air-conditioning apparatus, and more particularly, to the structure of a heat source-side heat exchanger.

Background Art [0002]

In an outdoor unit for an air-conditioning apparatus, during a heating operation in which an outdoor heat exchanger serves as an evaporator, frost may be formed on the outdoor heat exchanger, with the result that heat exchange may be hindered. To solve this problem, in general, such an air-conditioning apparatus performs a defrosting operation of removing the frost when the frost is formed.

[0003]

When the defrosting operation is performed, the frost adhering to the outdoor heat exchanger melts into drain water, and the drain water is discharged to an outside of the outdoor unit. At the time of discharge, the drain water may spatter and adhere to an inside of a casing of the outdoor unit.

In this case, when an outside air temperature is low, for example, at zero degrees Celsius or less, the drain water adhering to the inside of the casing may freeze before the drain water is discharged to the outside of the outdoor unit.

[0004]

To solve the above-mentioned problem, there has been proposed an airconditioning apparatus having a drainage structure capable of promptly discharging the drain water accumulated inside the outdoor unit to prevent freezing of the drain water (for example, see Patent Literature 1).

[0005]

Meanwhile, to improve performance, there has been proposed an outdoor unit in which two outdoor heat exchangers each having a substantially L shape are arranged symmetrically along an entire periphery of a casing of the outdoor unit (for example, see Patent Literature 2).

Citation List

Patent Literature [0006]

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2015-61997

Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2001-21284

Summary of Invention

Technical Problem [0007]

However, the outdoor unit described in Patent Literature 2 has a problem in that, when the drain water flowing out of the outdoor heat exchanger spatters and freezes on a panel on a service surface side (hereinafter referred to as service panel as appropriate), serviceability, that is, a capability of enabling maintenance work such as repair and maintenance to be performed easily is impaired.

Herein, the service surface refers to, among side surfaces forming the casing, a surface to be used by a worker when maintenance work (service) such as repair and maintenance is performed.

[0008]

The present invention has been made in view of the above-mentioned problems of the related art, and has an object to provide an air-conditioning apparatus and an outdoor unit for an air-conditioning apparatus that are capable of preventing spattering of drain water on a service panel provided in a casing of the outdoor unit, and capable of preventing freezing of the drain water.

Solution to Problem [0009]

An air-conditioning apparatus according to an embodiment of the present invention, includes an outdoor unit including a compressor, a refrigerant flow switching device, and a heat source-side heat exchanger, and an indoor unit including an expansion device and a use-side heat exchanger, in which the outdoor unit and the indoor unit are connected to each other by pipes, the outdoor unit, the indoor unit, and the pipes allow refrigerant to flow inside, the outdoor unit includes side surfaces of an outer shell formed of a plurality of panels each having an inlet through which air outside the outdoor unit is sucked, at least one of the plurality of panels serves as a service panel, the heat source-side heat exchanger includes a plurality of separate heat exchangers including a first heat source-side heat exchanger provided along one of the side surfaces that includes the service panel, and a second heat source-side heat exchanger provided along the other one of the side surfaces different from the one of the side surfaces that includes the service panel, and the first heat source-side heat exchanger has a flow passage of the refrigerant parallel to a flow of the air during a heating operation.

Advantageous Effects of Invention [0010]

As described above, according to an embodiment of the present invention, it is possible to prevent spattering of drain water on the service panel provided in the casing of the outdoor unit, and prevent freezing of the drain water.

Brief Description of Drawings [0011] [Fig. 1 ] Fig. 1 is a schematic view for illustrating an example of a circuit configuration of an air-conditioning apparatus according to Embodiment 1 of the present invention.

[Fig. 2] Fig. 2 is a perspective view for illustrating an example of an external appearance of an outdoor unit for the air-conditioning apparatus according to Embodiment 1 of the present invention.

[Fig. 3] Fig. 3 is a view for schematically illustrating a cross section of the example of the outdoor unit for the air-conditioning apparatus according to Embodiment 1 of the present invention as seen from the top.

[Fig. 4] Fig. 4 is a perspective view for illustrating an example of a first heat source-side heat exchanger 13a of Fig. 3.

[Fig. 5] Fig. 5 is a schematic view for illustrating an example of a circuit configuration of an air-conditioning apparatus according to Embodiment 2 of the present invention.

Description of Embodiments [0012]

Embodiment 1 (Air-conditioning Apparatus)

An air-conditioning apparatus according to Embodiment 1 of the present invention is described below.

Fig. 1 is a schematic view for illustrating an example of a circuit configuration of an air-conditioning apparatus 1 according to Embodiment 1 of the present invention. As illustrated in Fig. 1, the air-conditioning apparatus 1 includes an outdoor unit 10 and a plurality of indoor units 20 such as the indoor units 20A and 20B. The outdoor unit 10 and the plurality of indoor units 20 such as the indoor units 20A and 20B are connected to each other by refrigerant pipes 30. This example is an illustration of a case in which three indoor units 20A, 20B, and 20C are connected to one outdoor unit

10.

[0013]

The number of the indoor units 20 connected to the outdoor unit 10 is not limited to the number specified in this example. For example, one indoor unit 20 may be connected to one outdoor unit 10, or two indoor units 20 or four or more indoor units 20 may be connected to one outdoor unit 10. Further, for example, one or a plurality of indoor units 20 may be connected to a plurality of outdoor units 10. [0014] (Configuration of Outdoor Unit)

The outdoor unit 10 mainly includes a compressor 11, a refrigerant flow switching device 12 such as a four-way valve, a heat source-side heat exchanger (outdoor heat exchanger) 13, and an accumulator 14.

[0015]

The compressor 11 sucks in low-temperature and low-pressure refrigerant, compresses the refrigerant into a high-temperature and high-pressure state, and discharges the compressed refrigerant. As the compressor 11, for example, an inverter compressor capable of controlling a capacity can be used.

[0016]

The refrigerant flow switching device 12 performs switching between a cooling operation and a heating operation by switching a flow direction of the refrigerant. [0017]

The heat source-side heat exchanger 13 exchanges heat between the refrigerant and air supplied by a heat source-side air-sending device such as a fan (not shown). Specifically, during the cooling operation, the heat source-side heat exchanger 13 acts as a condenser configured to heat, for example, the air with use of heat of the refrigerant. Further, during the heating operation, the heat source-side heat exchanger 13 acts as an evaporator configured to evaporate the refrigerant to cool, for example, the air with use of evaporation heat of the refrigerant.

[0018]

The accumulator 14 is provided on a suction side of the compressor. The accumulator 14 accumulates, for example, an excess of the refrigerant generated due to a difference in operation conditions between the cooling operation and the heating operation, and an excess of the refrigerant generated due to a transitional change in operation.

[0019] (Configuration of Indoor Unit)

The indoor unit 20A includes a use-side heat exchanger (indoor heat exchanger) 21A and an expansion device 22A. The indoor unit 20B includes a useside heat exchanger (indoor heat exchanger) 21B and an expansion device 22B.

The indoor unit 20C includes a use-side heat exchanger (indoor heat exchanger) 21C and an expansion device 22C.

In the following description, when there is no particular need to distinguish the indoor units 20A, 20B, and 20C from one another, each of the indoor units 20A, 20B, and 20C is simply referred to as the indoor unit 20 as appropriate. Further, similarly, each of the use-side heat exchangers 21A to 21C is simply referred to as the use-side heat exchanger 21 as appropriate, and each of the expansion devices 22A to 22C is simply referred to as the expansion device 22 as appropriate.

[0020]

The use-side heat exchanger 21 exchanges heat between the refrigerant and the air supplied by a use-side air-sending device such as a fan (not shown). Thus, heating air or cooling air to be supplied into an indoor space is generated.

The use-side heat exchanger 21 acts as an evaporator during the cooling operation. Further, the use-side heat exchanger 21 acts as a condenser during the heating operation.

[0021]

The expansion device 22 is, for example, a valve, and reduces pressure of the refrigerant to expand the refrigerant. The expansion device 22 is constructed by, for example, a valve such as an electronic expansion valve capable of controlling an opening degree.

[0022] (Action of Air-conditioning Apparatus)

Next, description is made of movement of the refrigerant in a cooling operation mode or a defrosting operation mode and in a heating operation mode in the airconditioning apparatus 1 having the above-mentioned configuration.

In the example illustrated in Fig. 1, a state of the refrigerant flow switching device 12 indicated by the solid lines is a state in the cooling operation mode or the defrosting operation mode, and the flow direction of the refrigerant is indicated by the solid line. Further, a state of the refrigerant flow switching device 12 indicated by the dotted lines is a state in the heating operation mode, and the flow direction of the refrigerant is indicated by the dotted line.

[0023] (Cooling Operation Mode, Defrosting Operation Mode)

First, the movement of the refrigerant in the cooling operation mode or the defrosting operation mode is described.

In the cooling operation mode or the defrosting operation mode, the refrigerant flow switching device 12 is switched to the state indicated by the solid lines of Fig. 1. The low-temperature and low-pressure refrigerant is compressed by the compressor 11, and then is discharged as high-temperature and high-pressure gas refrigerant. [0024]

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the heat source-side heat exchanger 13 through the refrigerant flow switching device 12. The high-temperature and high-pressure gas refrigerant having flowed into the heat source-side heat exchanger 13 is condensed while transferring heat through heat exchange with outdoor air, and then flows out of the heat source-side heat exchanger 13 as high-pressure liquid refrigerant in a subcooled state.

[0025]

The high-pressure liquid refrigerant having flowed out of the heat source-side heat exchanger 13 is reduced in pressure by the expansion device 22 to become lowtemperature and low-pressure two-phase gas-liquid refrigerant, and then flows into the use-side heat exchanger 21. The low-temperature and low-pressure two-phase gas-liquid refrigerant having flowed into the use-side heat exchanger 21 cools indoor air by receiving heat and evaporating through heat exchange with the indoor air, and then flows out of the use-side heat exchanger 21 as low-temperature and lowpressure gas refrigerant.

[0026]

The low-temperature and low-pressure gas refrigerant having flowed out of the use-side heat exchanger 21 passes through the refrigerant flow switching device 12 and the accumulator 14, and is sucked into the compressor 11.

[0027] (Heating Operation Mode)

Next, the movement of the refrigerant in the heating operation mode is described.

In the heating operation mode, the refrigerant flow switching device 12 is switched to the state indicated by the dotted lines of Fig. 1. The low-temperature and low-pressure refrigerant is compressed by the compressor 11, and then is discharged as high-temperature and high-pressure gas refrigerant.

[0028]

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the use-side heat exchanger 21 through the refrigerant flow switching device 12. The high-temperature and high-pressure gas refrigerant having flowed into the use-side heat exchanger 21 is condensed while transferring heat through heat exchange with outdoor air, and then flows out of the use-side heat exchanger 21 as high-pressure liquid refrigerant in a subcooled state.

[0029]

The high-pressure liquid refrigerant having flowed out of the use-side heat exchanger 21 is reduced in pressure by the expansion device 22 to become lowtemperature and low-pressure two-phase gas-liquid refrigerant, and then flows into the heat source-side heat exchanger 13. The low-temperature and low-pressure two-phase gas-liquid refrigerant having flowed into the heat source-side exchanger 13 receives heat and evaporates through heat exchange with the outdoor air, and then flows out of the heat source-side heat exchanger 13 as low-temperature and lowpressure gas refrigerant.

[0030]

The low-temperature and low-pressure gas refrigerant having flowed out of the heat source-side heat exchanger 13 passes through the refrigerant flow switching device 12 and the accumulator 14, and is sucked into the compressor.

[0031] (Structure of Outdoor Unit)

Next, description is made of the structure of the outdoor unit 10 for the airconditioning apparatus 1 according to Embodiment 1.

Fig. 2 is a perspective view for illustrating an example of an external appearance of the outdoor unit 10 for the air-conditioning apparatus 1 according to Embodiment 1 of the present invention. Fig. 3 is a view for schematically illustrating a cross section of the example of the outdoor unit 10 for the air-conditioning apparatus 1 according to Embodiment 1 of the present invention as seen from the top. In Fig. 3, a portion indicated by the dotted lines is an illustration of a fan 51 provided on a top panel 50e to be described later. The fan 51 is not visible in the actual cross section.

[0032]

The outdoor unit 10 has, for example, a rectangular parallelepiped shape, and an outer shell of the outdoor unit 10 is formed of a casing 50.

The casing 50 includes a front panel 50a, a back panel 50b, two side panels 50c and 50d, the top panel 50e, and a bottom panel 50f. At least one of the panels 50a to 50d serves as a service panel, which is a panel on a service surface side. [0033]

The example illustrated in Fig. 2 is an illustration of a case in which the front panel 50a serves as the service panel. The panel serves as the service panel is not limited to the panel specified in this example. For example, another panel such as the side panel 50c and the side panel 50d may serve as the service panel.

[0034]

The front panel 50a, the back panel 50b, and the side panels 50c and 50d each have an inlet through which the outdoor air is sucked. Further, the fan 51 is provided on the top panel 50e. The fan 51 serves as a releasing mechanism configured to release the air in the outdoor unit 10 to an outdoor space.

[0035]

As illustrated in Fig. 3, the heat source-side heat exchanger 13 is provided inside the outdoor unit 10 along the panels 50a to 50d. In Embodiment 1, the heat source-side heat exchanger 13 includes a first heat source-side heat exchanger 13a and a second heat source-side heat exchanger 13b each having, for example, an L shape in plan view.

[0036]

The first heat source-side heat exchanger 13a is provided along the front panel 50a and the side panel 50d. The second heat source-side heat exchanger 13b is provided along the back panel 50b and the side panel 50c.

[0037]

A refrigerant inflow port 15a and a refrigerant outflow port 15b are formed in one end surface of each of the first heat source-side heat exchanger 13a and the second heat source-side heat exchanger 13b.

In the first heat source-side heat exchanger 13a, the refrigerant inflow port 15a is formed on a windward side of a flow of the outdoor air that is sucked through the front panel 50a, and the refrigerant outflow port 15b is formed on a leeward side of the flow of the outdoor air.

Meanwhile, in the second heat source-side heat exchanger 13b, the refrigerant inflow port 15a is formed on a leeward side of a flow of the outdoor air that is sucked through the back panel 50b, and the refrigerant outflow port 15b is formed on a windward side of the flow of the outdoor air.

[0038]

Fig. 4 is a perspective view for illustrating an example of the first heat sourceside heat exchanger 13a of Fig. 3.

The first heat source-side heat exchanger 13a includes a plurality of heat transfer tubes 16 and a plurality of fins 17 arranged in a plurality of columns along the flow direction of the air. Further, in the first heat source-side heat exchanger 13a, the heat transfer tubes 16 in the plurality of columns are provided in a plurality of rows along a direction perpendicular to the flow direction of the air.

The heat transfer tubes 16 are provided to pass through through-holes formed in the plurality of fins 17 arrayed at predetermined intervals, and the refrigerant flows in the heat transfer tubes 16.

[0039]

The first heat source-side heat exchanger 13a exchanges heat between the air passing through the plurality of fins 17, and the refrigerant flowing in the plurality of heat transfer tubes 16.

Through the fins 17, the first heat source-side heat exchanger 13a transfers heat of the refrigerant flowing in the heat transfer tubes 16 and heat of the air flowing outside the first heat source-side heat exchanger 13a. Thus, a surface area of a contact surface with the air is increased, and thereby heat can be efficiently exchanged between the refrigerant and the air.

[0040]

Fig. 4 is an illustration of the example in which the plurality of heat transfer tubes 16 arranged in the plurality of columns are provided in the plurality of rows, but the present invention is not limited to the example. For example, the number of the rows may be one.

[0041]

Next, description is made of a relationship between a refrigerant flow passage and a refrigerant temperature as well as a frost formation amount and an amount of melted frost water during the defrosting operation in the heat source-side heat exchanger 13 when the heat source-side heat exchanger 13 is used as an evaporator during the heating operation.

[0042] (Regarding Refrigerant Flow Passage and Change in Refrigerant Temperature)

When the refrigerant inflow port 15a of the heat source-side heat exchanger 13 is formed on the windward side of the flow of the air, and the refrigerant outflow port 15b is formed on the leeward side of the flow of the air, the refrigerant flows into the heat source-side heat exchanger 13 through the refrigerant inflow port 15a, and flows in the heat transfer tubes 16 in a windward-side column. Then, the refrigerant flows in the heat transfer tubes 16 in a leeward-side column, and flows out through the refrigerant outflow port 15b. Consequently, the heat source-side heat exchanger 13 serves as a parallel flow heat exchanger in which a flow direction of the refrigerant and the flow direction of the air conform to each other.

Meanwhile, when the refrigerant inflow port 15a of the heat source-side heat exchanger 13 is formed on the leeward side of the flow of the air, and the refrigerant outflow port 15b is formed on the windward side, the refrigerant flows into the heat source-side heat exchanger 13 through the refrigerant inflow port 15a, and flows in the heat transfer tubes 16 in the leeward-side column. Then, the refrigerant flows in the heat transfer tubes 16 in the windward side column, and flows out through the refrigerant outflow port 15b. Consequently, the heat source-side heat exchanger 13 serves as a counter-flow heat exchanger in which the flow direction of the refrigerant and the flow direction of the air are different from each other, or opposed to each other.

That is, in Embodiment 1, during the heating operation, the first heat sourceside heat exchanger 13a serves as the parallel flow heat exchanger, and the second heat source-side heat exchanger 13b serves as the counter-flow heat exchanger. [0043]

In general, two-phase refrigerant having flowed from the refrigerant inflow port into the heat exchanger used as an evaporator, flows in pipes in the heat exchanger while exchanging heat with the air having been sucked. However, in this process, pressure of the refrigerant is reduced due to pressure loss (friction loss) in the pipes, and a temperature of the refrigerant is reduced along with the reduction in pressure.

Consequently, in the heat exchanger, the temperature of the refrigerant is high at the refrigerant inflow port, and the temperature of the refrigerant is low at the refrigerant outflow port.

[0044]

In Embodiment 1, during the heating operation, the first heat source-side heat exchanger 13a serves as the parallel flow heat exchanger, the refrigerant inflow port 15a is formed on the windward side of the flow of the air, and the refrigerant outflow port 15b is formed on the leeward side. Consequently, the temperature of the refrigerant on the leeward side is low.

Further, during the heating operation, the second heat source-side heat exchanger 13b serves as the counter-flow heat exchanger, the refrigerant inflow port 15a is formed on the leeward side of the flow of the air, and the refrigerant outflow port 15b is formed on the windward side. Consequently, the temperature of the refrigerant on the windward side is low.

[0045] (Regarding Frost Formation Amount and Amount of Melted Frost Water during Defrosting Operation)

Meanwhile, during the heating operation, an amount of frost adhering to the heat exchanger, in other words, a frost formation amount, is increased as the temperature of the refrigerant is lower, and is reduced as the temperature of the refrigerant is higher.

Consequently, in Embodiment 1, in the first heat source-side heat exchanger 13a serving as the parallel flow heat exchanger, the frost formation amount is large on the leeward side having the refrigerant outflow port 15b, whereas the frost formation amount is small on the windward side having the refrigerant inflow port 15a.

Further, in the second heat source-side heat exchanger 13b serving as the counter-flow heat exchanger, the frost formation amount is large on the windward side having the refrigerant outflow port 15b, whereas the frost formation amount is small on the leeward side having the refrigerant inflow port 15a.

[0046]

During the defrosting operation, frost adhering to the heat source-side heat exchanger 13 during the heating operation melts and drips.

Consequently, the amount of melted frost water is large on the leeward side in the first heat source-side heat exchanger 13a serving as the parallel flow heat exchanger, whereas the amount of melted frost water is large on the windward side in the second heat source-side heat exchanger 13b serving as the counter-flow heat exchanger.

[0047]

As described above, in Embodiment 1, in the first heat source-side heat exchanger 13a provided along the service panel, the amount of melted frost water is large on the leeward side of the air that is sucked, and the amount of melted frost water can be reduced on the windward side. Consequently, drain water generated by melting of the frost adhering to the first heat source-side heat exchanger 13a can be prevented from adhering to and freezing on the front panel 50a, which serves as the service panel.

[0048]

Embodiment 2

Next, an air-conditioning apparatus according to Embodiment 2 of the present invention is described.

In the air-conditioning apparatus according to Embodiment 2, during the heating operation, a temperature of refrigerant flowing out of a heat source-side heat exchanger provided along a service panel is increased at a refrigerant outflow port.

In this manner, formation of frost on the heat source-side heat exchanger is prevented, and thereby an amount of drain water generated during the defrosting operation is reduced.

[0049] (Configuration of Air-conditioning Apparatus)

Fig. 5 is a schematic view for illustrating an example of a circuit configuration of an air-conditioning apparatus according to Embodiment 2 of the present invention.

In the following description, parts that are the same as those in Embodiment 1 are denoted by the same reference signs, and detailed description of the parts is omitted.

As illustrated in Fig. 5, the air-conditioning apparatus 2 includes an outdoor unit 100 and the plurality of indoor units 20 such as the indoor units 20A and 20B. The outdoor unit and the plurality of indoor units are connected to each other by the refrigerant pipes 30.

[0050] (Configuration of Outdoor Unit)

The outdoor unit 100 mainly includes the compressor 11, the refrigerant flow switching device 12, the heat source-side heat exchanger 13, the accumulator 14, and a refrigerant flow rate regulating mechanism 110.

[0051]

Similarly to Embodiment 1, for example, the heat source-side heat exchanger 13 includes the first heat source-side heat exchanger 13a and the second heat source-side heat exchanger 13b, and the first heat source-side heat exchanger 13a is provided along the service panel (front panel 50a).

[0052]

The refrigerant flow rate regulating mechanism 110 regulates a flow rate of the refrigerant to cause the refrigerant to flow into the first heat source-side heat exchanger 13a at a preset flow rate during the heating operation.

As the refrigerant flow rate regulating mechanism 110, for example, there can be used a mechanism in which at least one of a diameter and a length of a pipe connected to the first heat source-side heat exchanger 13a is adjusted so that the refrigerant flows at the preset flow rate during the heating operation.

The refrigerant flow rate regulating mechanism 110 is not limited to the configuration described above. For example, as the refrigerant flow rate regulating mechanism 110, an electronic expansion valve may be used, and an opening degree of the electronic expansion valve may be set to a preset predetermined opening degree. When the electronic expansion valve is used as the refrigerant flow rate regulating mechanism 110, the opening degree of the electronic expansion valve during the cooling operation may be set to, for example, an opening degree that is set as described above, or may be set to a fully-open opening degree.

[0053] (Configuration of Indoor Unit)

The indoor unit 20A includes the use-side heat exchanger (indoor heat exchanger) 21A and the expansion device 22A. The indoor unit 20B includes the use-side heat exchanger (indoor heat exchanger) 21B and the expansion device 22B. The indoor unit 20C includes the use-side heat exchanger (indoor heat exchanger)

21C and the expansion device 22C. Each of the indoor units 20A, 20B, and 20C has the same configuration as that in Embodiment 1, and hence description of the indoor units 20 is omitted.

[0054] (Action of Air-conditioning Apparatus)

Next, description is made of movement of the refrigerant in the heating operation mode in the air-conditioning apparatus 2 having the above-mentioned configuration. The refrigerant flow rate regulating mechanism 110 does not operate in the cooling operation mode or the defrosting operation mode, and hence the movement of the refrigerant in the cooling operation mode or the defrosting operation mode is the same as that in Embodiment 1. Thus, description of the movement is omitted.

In the example illustrated in Fig. 5, a state and a flow direction of the refrigerant during the heating operation are illustrated.

[0055] (Heating Operation Mode)

In the heating operation mode, the refrigerant flow switching device 12 is switched to the state illustrated in Fig. 5. The low-temperature and low-pressure refrigerant is compressed by the compressor 11, and then is discharged as hightemperature and high-pressure gas refrigerant.

[0056]

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the use-side heat exchanger 21 through the refrigerant flow switching device 12. The high-temperature and high-pressure gas refrigerant having flowed into the use-side heat exchanger 21 is condensed while transferring heat through heat exchange with indoor air, and then flows out of the use-side heat exchanger 21 as high-pressure liquid refrigerant in a subcooled state.

[0057]

The high-pressure liquid refrigerant having flowed out of the use-side heat exchanger 21 is reduced in pressure by the expansion device 22 to become lowtemperature and low-pressure two-phase gas-liquid refrigerant. The lowtemperature and low-pressure two-phase gas-liquid refrigerant is divided by branching flow passages and flows into the refrigerant flow rate regulating mechanism 110 and the second heat source-side heat exchanger 13b.

[0058]

After the flow rate of the low-temperature and low-pressure two-phase gasliquid refrigerant having flowed into the refrigerant flow rate regulating mechanism 110 is regulated to the preset flow rate, the low-temperature and low-pressure twophase gas-liquid refrigerant flows out of the refrigerant flow rate regulating mechanism 110, and then flows into the first heat source-side heat exchanger 13a.

The low-temperature and low-pressure two-phase gas-liquid refrigerant having flowed into the first heat source-side heat exchanger 13a receives heat and evaporates through heat exchange with the outdoor air to become low-temperature and low-pressure gas refrigerant, and the low-temperature and low-pressure gas refrigerant flows out of the first heat source-side heat exchanger 13a.

[0059]

Meanwhile, the low-temperature and low-pressure two-phase gas-liquid refrigerant having flowed into the second heat source-side heat exchanger 13b receives heat and evaporates through heat exchange with the outdoor air to become low-temperature and low-pressure gas refrigerant, and the low-temperature and low17 pressure gas refrigerant flows out of the second heat source-side heat exchanger 13b.

[0060]

The low-temperature and low-pressure gas refrigerant having flowed out of the first heat source-side heat exchanger 13a and the low-temperature and low-pressure gas refrigerant having flowed out of the second heat source-side heat exchanger 13b are joined by a joining flow passage, and are sucked into the compressor through the refrigerant flow switching device 12 and the accumulator 14.

[0061]

Next, description is made of the relationship between the refrigerant flow passage and the refrigerant temperature as well as the frost formation amount and the amount of melted frost water during the defrosting operation in the heat sourceside heat exchanger 13 when the heat source-side heat exchanger 13 is used as an evaporator during the heating operation.

[0062] (Regarding Relationship between Surface Area of Heat Source-Side Heat Exchanger and Refrigerant Temperature)

In general, when a surface area of a heat exchanger to be used as an evaporator is reduced, a temperature of refrigerant flowing out through a refrigerant outflow port of the heat exchanger is lower as compared to a case in which the surface area of the heat exchanger is large.

That is, a temperature of the refrigerant flowing in the heat exchanger having a large surface area is high at the refrigerant outflow port.

[0063] (Regarding Regulation of Flow Rate of Refrigerant)

Further, when the flow rate of the refrigerant flowing into the heat exchanger is sufficiently low in relation to a heat exchange capacity of the heat exchanger, pressure loss of the refrigerant flowing in the heat exchanger is reduced. Consequently, a degree of reduction in temperature of the refrigerant due to pressure loss is smaller as compared to a case in which the flow rate of the refrigerant is sufficient in relation to the heat exchange capacity of the heat exchanger.

As described above, when the flow rate of the refrigerant flowing into the heat exchanger is sufficiently low in relation to the heat exchange capacity of the heat exchanger, the refrigerant having flowed out through the refrigerant outflow port flows out in a state of having a large degree of superheat. As a result, the temperature of the refrigerant is higher as compared to a case in which the flow rate of the refrigerant is sufficient.

[0064]

In Embodiment 2, the flow rate of the refrigerant flowing into the first heat source-side heat exchanger 13a is regulated by the refrigerant flow rate regulating mechanism 110 to be sufficiently low in relation to a heat exchange capacity of the first heat source-side heat exchanger 13a. Thus, the refrigerant having flowed out of the first heat source-side heat exchanger 13a flows out in a state of having a large degree of superheat. As a result, the temperature of the refrigerant is higher as compared to the case in which the flow rate of the refrigerant is sufficient in relation to the heat exchange capacity of the first heat source-side heat exchanger 13a.

[0065]

The flow rate of the refrigerant to be regulated by the refrigerant flow rate regulating mechanism 110, in other words, the flow rate of the refrigerant flowing into the first heat source-side heat exchanger 13a, can be regulated so that the flow rate of the refrigerant is equal to or lower than a flow rate of the refrigerant that is obtained by, for example, multiplying a capacity ratio that is obtained by dividing the heat exchange capacity of the first heat source-side heat exchanger 13a by a heat exchange capacity of an entirety of the heat source-side heat exchanger 13, by a flow rate of the refrigerant flowing in the entirety of the heat source-side heat exchanger 13 together.

[0066]

As described above, when the surface area of the heat exchanger is increased or the flow rate of the refrigerant flowing into the heat exchanger is reduced, the refrigerant can be caused to flow out of the heat exchanger, in a high temperature state.

Thus, during the heating operation, the frost formation amount on the heat source-side heat exchanger is reduced, and thus an amount of drain water generated during the defrosting operation can be reduced.

[0067]

In Embodiment 2, the surface area of the first heat source-side heat exchanger 13a is reduced, and the flow rate of the refrigerant flowing into the first heat sourceside heat exchanger 13a is regulated by the refrigerant flow rate regulating mechanism 110 so that the flow rate of the refrigerant is sufficiently low in relation to the heat exchange capacity of the first heat source-side heat exchanger 13a.

In this manner, as high-temperature superheated gas, the refrigerant can be caused to flow out through the refrigerant outflow port 15b of the first heat source-side heat exchanger 13a, and the amount of drain water generated during the defrosting operation can be reduced.

[0068]

As described above, according to Embodiment 2, the surface area of the first heat source-side heat exchanger 13a is reduced, and the flow rate of the refrigerant flowing into the first heat source-side heat exchanger 13a is regulated by the refrigerant flow rate regulating mechanism 110 so that the flow rate of the refrigerant is sufficiently low in relation to the heat exchange capacity of the first heat source-side heat exchanger 13a. Thus, the amount of drain water generated during the defrosting operation can be reduced, and freezing of drain water on the service panel can be prevented.

[0069]

In the above, Embodiment 1 and Embodiment 2 ofthe present invention are described. However, the present invention is not limited to Embodiment 1 and Embodiment 2 of the present invention described above. Various modifications and applications can be made without departing from the gist of the present invention. [0070]

For example, in the above-mentioned examples, description is made of the case in which the first heat source-side heat exchanger 13a and the second heat source-side heat exchanger 13b each having an L shape are used as the heat source-side heat exchanger 13, but the present invention is not limited to the examples. For example, four heat source-side heat exchangers each having a flatplate-like shape may be each arranged along a corresponding one of the panels 50a to 50d.

In this case, in a flat-plate-like heat source-side heat exchanger arranged along the front panel 50a serving as the service panel, the refrigerant inflow port 15a is formed on the windward side of the air that is sucked, and the refrigerant outflow port 15b is formed on the leeward side. With this configuration, the flat-plate-like heat source-side heat exchanger serves as a parallel flow heat exchanger, and hence the same actions and effects as those of Embodiment 1 described above can be obtained.

Further, for example, a flat-plate-like heat source-side heat exchanger may be arranged along the service panel, for example, the front panel 50a, and a heat source-side heat exchanger having a shape formed by three adjacent sides may be arranged along panels other than the service panel, for example, the panels 50b to 50d.

[0071]

Still further, in the above-mentioned examples, description is made ofthe case in which the refrigerant inflow port 15a and the refrigerant outflow port 15b are formed in the same end surface of the heat source-side heat exchanger 13, but the present invention is not limited to the examples. In the heat source-side heat exchanger arranged along the front panel 50a serving as the service panel, the refrigerant outflow port 15b may be formed on the leeward side, and the refrigerant inflow port 15a and the refrigerant outflow port 15b may be formed in different end surfaces.

Reference Signs List [0072]

1,2 air-conditioning apparatus 10 outdoor unit 11 compressor 12 refrigerant flow switching device 13 heat source-side heat exchanger 13a first heat source-side heat exchanger 13b second heat source-side heat exchanger accumulator 15a refrigerant inflow port 15b refrigerant outflow 5 port 16 heat transfer tube 17 fin 20, 20A, 20B, 20C indoor unit 21,21 A,

21B, 21C use-side heat exchanger 22, 22A, 22B, 22C expansion device30 refrigerant pipe 50 casing 50a front panel 50b back panel 50c, 50d side panel 50e top panel 50f bottom panel 51 fan 100 outdoor unit 110 refrigerant flow rate regulating mechanism

Claims

CLAIMS [Claim 1]

An air-conditioning apparatus, comprising:

an outdoor unit including a compressor, a refrigerant flow switching device, and a heat source-side heat exchanger; and an indoor unit including an expansion device and a use-side heat exchanger, the outdoor unit and the indoor unit being connected to each other by pipes, the outdoor unit, the indoor unit, and the pipes allowing refrigerant to flow inside, the outdoor unit including side surfaces of an outer shell formed of a plurality of panels each having an inlet through which air outside the outdoor unit is sucked, at least one of the plurality of panels serving as a service panel, the heat source-side heat exchanger including a plurality of separate heat exchangers including a first heat source-side heat exchanger provided along one of the side surfaces that includes the service panel, and a second heat source-side heat exchanger provided along an other one of the side surfaces different from the one of the side surfaces that includes the service panel, the first heat source-side heat exchanger having a flow passage of the refrigerant parallel to a flow of the air during a heating operation.
[Claim 2]

The air-conditioning apparatus of claim 1, further comprising a refrigerant flow rate regulating mechanism configured to regulate a flow rate of the refrigerant flowing into the first heat source-side heat exchanger during the heating operation.
[Claim 3]

The air-conditioning apparatus of claim 2, wherein the refrigerant flow rate regulating mechanism is configured to regulate the flow rate of the refrigerant flowing into the first heat source-side heat exchanger so that the flow rate of the refrigerant is equal to or lower than a flow rate of the refrigerant that is obtained by multiplying a capacity ratio that is obtained by dividing a heat exchange capacity of the first heat source-side heat exchanger by a heat exchange capacity of an entirety of the heat source-side heat exchanger, by a flow rate of the refrigerant flowing in the entirety of the heat source-side heat exchanger together.
[Claim 4]

The air-conditioning apparatus of any one of claims 1 to 3, wherein the first heat source-side heat exchanger has an L shape, and is provided along the service panel and a panel adjacent to the service panel.
[Claim 5]

The air-conditioning apparatus of any one of claims 1 to 3, wherein the first heat source-side heat exchanger has a flat-plate-like shape, and is provided along the service panel.
[Claim 6]

The air-conditioning apparatus of any one of claims 1 to 5, wherein, in the first heat source-side heat exchanger, a refrigerant inflow port through which the refrigerant flows in is formed on a windward side of the flow of the air that is sucked, and a refrigerant outflow port through which the refrigerant flows out is formed on a leeward side of the flow of the air that is sucked.
[Claim 7]

The air-conditioning apparatus of claim 6, wherein the refrigerant inflow port and the refrigerant outflow port of the first heat source-side heat exchanger are formed in a single end surface of the first heat source-side heat exchanger.
[Claim 8]

The air-conditioning apparatus of claim 6, wherein the refrigerant inflow port and the refrigerant outflow port of the first heat source-side heat exchanger are formed in different end surfaces of the first heat source-side heat exchanger.
[Claim 9]

An outdoor unit for an air-conditioning apparatus, comprising: a compressor;

a refrigerant flow switching device; and a heat source-side heat exchanger, the compressor, the refrigerant flow switching device, and the heat source-side heat exchanger being connected to each other by pipes, the compressor, the refrigerant flow switching device, the heat source-side heat exchanger, and the pipes allowing refrigerant to flow inside, the outdoor unit including side surfaces of an outer shell formed of a plurality of panels each having an inlet through which air outside the outdoor unit is sucked, at least one of the plurality of panels serving as a service panel, the heat source-side heat exchanger including a plurality of separate heat exchangers including a first heat source-side heat exchanger provided along one of the side surfaces that includes the service panel, and a second heat source-side heat exchanger provided along an other one of the side surfaces different from the one of the side surfaces that includes the service panel, in the first heat source-side heat exchanger, a refrigerant inflow port through which the refrigerant flows in being formed on a windward side of a flow of the air that is sucked, and a refrigerant outflow port through which the refrigerant flows out being formed on a leeward side of the flow of the air that is sucked, the first heat source-side heat exchanger having a flow passage of the refrigerant parallel to the flow of the air during a heating operation.