JP2010060183A - Air conditioner - Google Patents

Abstract

An air conditioner capable of further improving the efficiency of a defrost operation while suppressing frost formation on a heat exchange surface by a coating film having water slidability and water repellency.
An outdoor heat exchanger of an air conditioner has a heat exchanger upper part 2a and a heat exchanger lower part 2b connected in parallel with the heat exchanger upper part 2a. An upper expansion valve 31 and a first lower expansion valve 32 are provided between the indoor heat exchanger 4 and the heat exchanger upper portion 2a and the heat exchanger lower portion 2b, respectively. With this configuration, the defrosting operation is performed independently for the heat exchanger upper part 2a and the heat exchanger lower part 2b.
[Selection] Figure 1

Description

  The present invention relates to an outdoor heat exchanger in which a refrigerant is circulated by a heat exchange tube penetrating a plate fin and a coating film having slidability and water repellency is provided on a heat exchange surface of the plate fin. About.

  The air conditioner adjusts the temperature of the room by pumping up indoor heat during the cooling operation and pumping up outdoor heat during the heating operation. In addition, an air conditioner is known that includes an indoor unit installed indoors and an outdoor unit installed outdoor.

  Moreover, an air conditioner operates a heat exchanger as an evaporator at the time of heating operation. Here, when the temperature of the air that exchanges heat with the heat exchanger is low or when the evaporation temperature is low, frost is formed on the heat exchange surface of the heat exchanger. When the heat exchange surface is frosted, the capacity of the heat exchanger is reduced, so that the refrigeration capacity of the air conditioner is also reduced.

  In particular, the outdoor unit of the air conditioner is directly affected by the outdoor air, so when the temperature of the outdoor air decreases during heating operation, the evaporation capacity of the outdoor heat exchanger operating as an evaporator decreases, It causes a decrease in the heating capacity of the air conditioner. Therefore, it is known that in an air conditioner, a defrosting operation (hereinafter referred to as “defrost operation”) for removing frost adhering to the outdoor heat exchanger is appropriately performed.

  However, when the defrosting operation is performed, the heating operation is stopped or the heating capacity is lowered, and thus there is a problem that the heating comfort sensitivity is lowered. Therefore, it has been a challenge to reduce the frequency of suspension of heating operation by suppressing frost formation in the heat exchanger and to shorten the defrosting operation time.

  As a method for solving this problem, as compared with a heat exchange surface that has not been subjected to surface treatment (hereinafter referred to as an “untreated heat exchange surface”), the slippage and water repellency are increased to prevent frost formation. There has been proposed a method for reducing the amount of frost formation on a heat exchanger operating as an evaporator by providing a frost suppression layer on a heat exchange surface (see, for example, Patent Document 1).

Here, with reference to FIG. 10, the structure of the conventional outdoor unit which provided the said frost formation suppression layer in the heat exchange surface is demonstrated.
The heat exchanger 100 is a so-called cross fin and tube heat exchanger. In addition, a large number of plate fins 101 are arranged on the heat exchange surface with a certain interval, and a heat exchange pipe 102 through which a refrigerant flows is passed through these plate fins 101. The plate fins 101 are arranged so that the longitudinal direction is parallel to the vertical direction, and the fin rows in which the plate fins 101 are arranged along the direction perpendicular to the air circulation direction 103 are arranged along the air circulation direction 103. It is arranged in a column. The heat exchange pipes 102 are arranged at equal intervals along the vertical direction of the plate fins 101. The surface of the plate fin 101 which is a heat exchange surface is provided with, for example, the frosting suppression layer described above, and the water slidability and water repellency are increased. A drain pan 106 for receiving and discharging water droplets 105 flowing downward from the heat exchanger 100 is disposed below the heat exchanger 100. The upper surface 106 a of the drain pan 106 contacts the entire lower end portion of the heat exchanger 100, that is, the entire lower end portion 101 a of the plate fin 101.

When the frosting suppression layer is provided on the heat exchanger in this way to increase the water slidability and water repellency of the heat exchange surface, the heat exchanger 100 condenses on the heat exchange surface when operated as an evaporator. Water droplets quickly flow downward from above the heat exchanger 100. Thereby, the quantity of the water droplet adhering to a heat exchange surface is reduced, and the amount of frost formation on a heat exchange surface can be reduced.
JP 2002-323298 A

  By the way, in the heat exchanger 100, since the frosting suppression layer is provided in the heat exchanger to increase the water slidability and water repellency of the heat exchange surface, the amount of water droplets 105 attached to the lower part of the plate fin 101 is More than the amount of water droplets 105 adhering to the top of the fin 101. Therefore, the frosting amount at the lower part of the plate fin 101 is larger than the frosting amount at the upper part of the plate fin 101.

  However, under the operating conditions of the conventional defrost operation, the defrost operation is performed by detecting by a sensor or the like when the heat exchange capacity of the heat exchanger is significantly reduced due to an increase in the amount of frost formation on the heat exchange surface. That is, since the defrosting operation is performed on the entire plate fin 101 regardless of the upper and lower portions of the plate fin 101 even though the amount of frost formation on the upper portion of the plate fin 101 is small, the defrosting operation is performed. This leaves room for improvement in terms of efficiency.

  Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to further suppress defrosting while suppressing frost formation on the heat exchange surface by a coating film having water slidability and water repellency. An object is to provide an air conditioner that can increase efficiency.

  The invention according to claim 1 is an outdoor heat exchanger in which a refrigerant is circulated by a heat exchange tube penetrating a plate fin and a coating film having water slidability and water repellency is provided on a heat exchange surface of the plate fin; An air conditioner comprising a defrost device that performs a defrost operation on the outdoor heat exchanger, wherein the outdoor heat exchanger is a fin upper portion that is positioned above the plate fin, and the fin upper portion. A heat exchanger upper part including the first tube as the heat exchange tube penetrating through the heat exchanger, and a fin lower part located below the heat exchanger and located below the plate fin as a part of the plate fin And a heat exchanger lower part including a second tube as the heat exchange tube penetrating the fin lower part, and these heat exchanger upper parts The first tube and the second tube are configured as independent systems, and the defrost device includes the heat exchanger. The refrigerant control of the upper part and the refrigerant control of the lower part of the heat exchanger are individually performed, and the defrosting ability of the defrosting operation for the upper part of the heat exchanger is made smaller than the defrosting ability of the defrosting operation for the lower part of the heat exchanger. This is the gist.

  According to the present invention, defrosting can be performed on the upper and lower portions of the outdoor heat exchanger, that is, the fin upper portion and the fin lower portion of the plate fin. The degree of freedom of control can be improved. Moreover, since the defrosting capability of the defrost operation is high for the fin lower portion where the amount of frost formation is larger than the fin upper portion, the fin lower portion is actively defrosted (hereinafter referred to as “defrost”) compared to the fin upper portion. can do. Therefore, since it is possible to make a difference in the defrosting capacity of the defrosting operation with respect to the upper part of the fin and the lower part of the fin, the defrosting operation is performed uniformly with respect to the entire plate fin, that is, without making a difference in the defrosting capacity of the defrosting operation. Compared with the case where it performs, the efficiency of a defrost driving | operation can be improved. The defrost ability can be evaluated as, for example, the amount of frost that can be defrosted per unit time.

  According to a second aspect of the present invention, in the air conditioner according to the first aspect, the defrost device is configured such that the number of executions of the defrost operation for the upper part of the heat exchanger is greater than the number of executions of the defrost operation for the lower part of the heat exchanger. The gist is to reduce it.

  According to this invention, compared with the heat exchanger lower part, by reducing the number of executions of the defrost operation on the upper part of the heat exchanger with a small amount of frost formation, It is possible to suppress defrosting operation on the heat exchanger in a state where the amount of frost formation is small.

  According to a third aspect of the present invention, in the air conditioner according to the first or second aspect, the defrost device sets an execution time per defrost operation for the upper part of the heat exchanger to the lower part of the heat exchanger. The gist is to make it shorter than the execution time per defrost operation.

  According to this invention, compared with the lower part of the heat exchanger, the frosting amount on the upper part of the heat exchanger is not frosted by shortening the execution time per defrost operation of the upper part of the heat exchanger with a small amount of frost formation. Even in a state or a state where the amount of frost formation is very small, it is possible to suppress the defrosting operation from being continued on the upper part of the heat exchanger.

  According to a fourth aspect of the present invention, in the air conditioner according to any one of the first to third aspects, the defrost device is provided at the upper portion of the heat exchanger during defrost operation with respect to the upper portion of the heat exchanger. The gist is to make the refrigerant flow rate smaller than the refrigerant flow rate in the lower part of the heat exchanger during the defrost operation with respect to the lower part of the heat exchanger.

  According to this invention, the difference in the amount of frost formation between the upper part of the heat exchanger and the lower part of the heat exchanger can be reduced by making the refrigerant flow rate at the upper part of the heat exchanger smaller than the refrigerant flow rate at the lower part of the heat exchanger. Therefore, in order to suppress the heat exchanger capacity of the heat exchanger from significantly decreasing, the frequency of performing the defrost operation can be reduced even under the operating conditions of the conventional defrost operation.

  Invention of Claim 5 is the air conditioner of any one of Claims 1-4. WHEREIN: The said defrost apparatus is on condition that the heating operation of the said air conditioner is made | formed. The gist is that the defrosting capability of the defrosting operation for the upper part of the heat exchanger is necessarily made smaller than the defrosting capability of the defrosting operation for the lower part of the heat exchanger.

The gist of the invention according to claim 6 is that, in the air conditioner according to claim 1, the defrost device performs the defrost operation only on the lower part of the heat exchanger.
According to this invention, since the defrost operation is performed only on the lower part of the heat exchanger with a large amount of frost formation, frost growth and frost formation at the lower part of the heat exchanger can be easily suppressed.

  The invention according to claim 7 includes an outdoor heat exchanger in which a refrigerant is circulated by a heat exchange tube penetrating the plate fin and a coating film having slidability and water repellency is provided on a heat exchange surface of the plate fin. In the air conditioner, the outdoor heat exchanger includes a fin upper portion located above the plate fin as a part of the plate fin, and a first tube serving as the heat exchange tube penetrating the fin upper portion. An upper portion, a lower portion of the plate fin that is positioned below the upper portion of the heat exchanger, and a second tube serving as the heat exchange tube that penetrates the lower portion of the fin; The heat exchanger is divided into a heat exchanger lower part including the upper part of the heat exchanger and a lower part of the heat exchanger to form a single heat exchanger. It said second tube and is intended to be configured as a system independent of each other, and summarized in that the heat exchange performance of the lower the heat exchanger is set smaller than the heat exchanging performance of the heat exchanger top.

  According to the present invention, the amount of water droplets adhering to the lower part of the heat exchanger can be reduced by setting the heat exchange performance of the lower part of the heat exchanger to be smaller than the heat exchange performance of the upper part of the heat exchanger. Therefore, since the amount of frost formation at the lower part of the heat exchanger can be reduced, it is possible to suppress the growth of frost from the lower part of the heat exchanger toward the upper part of the heat exchanger. As a result, by reducing the amount of frost formation at the lower part of the heat exchanger, it is possible to suppress the operation of the defrost operation even in the operation conditions of the defrost operation of the conventional defrost operation, thereby improving the efficiency of the defrost operation. it can.

The invention according to claim 8 is the air conditioner according to claim 6 or 7, wherein the outdoor heat exchanger has a total area of a heat exchange surface at a lower part of the heat exchanger. The gist is that it is smaller than the total area of the upper heat exchange surface.
According to the present invention, the amount of water droplets adhering to the lower part of the heat exchanger is reduced by making the total area of the heat exchange surfaces at the lower part of the heat exchanger smaller than the total area of the heat exchange surfaces at the upper part of the heat exchanger. Can do. Therefore, the amount of frost formation at the lower part of the heat exchanger can be reduced. As a result, it is possible to suppress frost growth from the lower part of the heat exchanger toward the upper part of the heat exchanger.

  The invention according to claim 9 includes an outdoor heat exchanger in which a refrigerant is circulated by a heat exchange tube penetrating the plate fin and a coating film having water slidability and water repellency is provided on a heat exchange surface of the plate fin. In the air conditioner, the outdoor heat exchanger includes a fin upper portion located above the plate fin as a part of the plate fin, and a first tube serving as the heat exchange tube penetrating the fin upper portion. An upper portion, a lower portion of the plate fin that is positioned below the upper portion of the heat exchanger, and a second tube serving as the heat exchange tube that penetrates the lower portion of the fin; The heat exchanger is divided into a heat exchanger lower part including the upper part of the heat exchanger and a lower part of the heat exchanger to form a single heat exchanger. And the second tube are configured as an independent system, and the interval between the second tubes in the vertical direction of the lower part of the heat exchanger is the first tubes in the vertical direction of the upper part of the heat exchanger. The gist is that it is set to be larger than the interval.

  According to this invention, compared with the space | interval of the 1st tubes of a heat exchanger upper part, in being formed so that the space | interval of the 2nd tubes of a heat exchanger lower part may become large, in a heat exchanger lower part, Moreover, since it can suppress that frost is formed between 2nd tubes, it can suppress that frost grows toward a heat exchanger upper part from a heat exchanger lower part. Therefore, by reducing the amount of frost formation at the lower part of the heat exchanger, it is possible to suppress the operation of the defrost operation even under the operation conditions of the defrost operation of the conventional defrost operation, so that the efficiency of the defrost operation can be increased. .

  A tenth aspect of the present invention is the air conditioner according to any one of the seventh to ninth aspects, wherein the air conditioner performs a defrost operation on the outdoor heat exchanger. The defrost device is characterized in that the refrigerant control at the upper part of the heat exchanger and the refrigerant control at the lower part of the heat exchanger are individually performed.

  According to this invention, the outdoor heat exchanger can be efficiently defrosted by separately performing the refrigerant control at the upper part of the heat exchanger and the refrigerant control at the lower part of the heat exchanger. Therefore, the efficiency of the defrost operation can be increased.

  The invention according to claim 11 is an outdoor heat exchanger in which a refrigerant is circulated by a heat exchange tube penetrating the plate fin and a coating film having water slidability and water repellency is provided on a heat exchange surface of the plate fin; In the air conditioner including a defrost device that performs a defrost operation on the outdoor heat exchanger, the outdoor heat exchanger includes a first fin provided as a part of the plate fin, and the first fin A first heat exchanger configured to include a first tube as the heat exchange tube penetrating the fin, and provided below the first heat exchanger, as a part of the plate fin A second heat exchanger configured to include a second fin provided below and a second tube as the heat exchange tube penetrating the second fin. In addition, the first tube and the second tube are configured as independent systems, and the defrost device includes refrigerant control for the first heat exchanger and refrigerant control for the second heat exchanger. And the defrosting capability of the defrosting operation for the first heat exchanger is made smaller than the defrosting capability of the defrosting operation for the second heat exchanger.

  According to this invention, since it becomes possible to defrost to the upper part and lower part of an outdoor heat exchanger, ie, each of the 1st fin and 2nd fin of a plate fin, it carries out with respect to an outdoor heat exchanger. The degree of freedom in controlling the defrost operation can be improved. Moreover, since the defrost capability of defrost operation is high about the 2nd fin with much frost formation compared with a 1st fin, a 2nd fin can be defrosted actively compared with a 1st fin. Therefore, since it is possible to make a difference in the defrosting performance of the defrosting operation with respect to the first fin and the second fin, it is uniform over the whole plate fin, that is, without making a difference in the defrosting operation of the defrosting operation. Compared with the case where defrost operation is performed, the efficiency of defrost operation can be improved.

  According to a twelfth aspect of the present invention, in the air conditioner according to the eleventh aspect, the defrost device sets the number of executions of the defrost operation for the first heat exchanger to the number of executions of the defrost operation for the second heat exchanger. The main point is to make it less.

  According to this invention, compared with the second heat exchanger, the first heat exchanger is not frosted by reducing the number of times of defrost operation of the first heat exchanger with a small amount of frost formation. Or, in a state where the amount of frost formation is very small, it is possible to suppress the defrost operation from being performed on the first heat exchanger.

Invention of Claim 13 in the air conditioner of Claim 11 or Claim 12,
The gist of the defrosting apparatus is to make an execution time per defrost operation for the first heat exchanger shorter than an execution time per defrost operation for the second heat exchanger.

  According to this invention, compared with the second heat exchanger, the first heat exchanger is frosted by reducing the execution time per defrost operation of the first heat exchanger with a small amount of frost formation. Even in a state where the defrosting operation is not performed, or in a state where the amount of frost formation is very small, it is possible to prevent the first heat exchanger from continuing the defrost operation.

  In a fourteenth aspect of the present invention, in the air conditioner according to any one of the eleventh to thirteenth aspects, the defrost device is configured to perform the first heat exchange during a defrost operation with respect to the first heat exchanger. The gist of the invention is to make the refrigerant flow rate of the cooler smaller than the refrigerant flow rate of the second heat exchanger during the defrost operation for the second heat exchanger.

  According to this invention, the difference in the amount of frost formation between the first heat exchanger and the second heat exchanger is reduced by making the refrigerant flow rate of the first heat exchanger smaller than the refrigerant flow rate of the second heat exchanger. be able to. Therefore, in order to suppress the heat exchanger capacity of the heat exchanger from significantly decreasing, the frequency of performing the defrost operation can be reduced even under the operating conditions of the conventional defrost operation.

  The invention according to claim 15 is the air conditioner according to any one of claims 11 to 14, wherein the defrost device is on the condition that a heating operation of the air conditioner is performed. The gist is to make the defrost capability of the defrost operation for the first heat exchanger smaller than the defrost capability for the second heat exchanger.

The gist of a sixteenth aspect of the present invention is that, in the air conditioner according to the eleventh aspect, the defrost device performs a defrost operation only on the second heat exchanger.
According to this invention, according to this invention, since the defrost operation is performed only for the second heat exchanger with a large amount of frost formation, frost growth and frost formation of the second heat exchanger are easily suppressed. can do.

  The invention according to claim 17 is an outdoor heat exchanger in which a refrigerant is circulated by a heat exchange tube penetrating a plate fin and a coating film having water slidability and water repellency is provided on a heat exchange surface of the plate fin; In the air conditioner including a defrost device that performs a defrost operation on the outdoor heat exchanger, the outdoor heat exchanger includes a first fin provided as a part of the plate fin, and the first fin The first heat exchanger configured to include the first tube as the heat exchange tube penetrating the fin, and provided below the first heat exchanger, as a part of the plate fin A second heat exchanger configured to include a second fin provided below and a second tube as the heat exchange tube penetrating the second fin. In addition, the first tube and the second tube are configured as independent systems, and the heat exchange performance of the second heat exchanger is set smaller than the heat exchange performance of the first heat exchanger. The gist is that

  According to this invention, the amount of water droplets adhering to the second heat exchanger can be reduced by setting the heat exchange performance of the second heat exchanger to be smaller than the heat exchange performance of the first heat exchanger. it can. Therefore, by reducing the frost formation amount of the second heat exchanger, it is possible to suppress the operation of the defrost operation even under the operation conditions of the conventional defrost operation, so that the efficiency of the defrost operation can be improved. it can.

  The invention according to claim 18 is the air conditioner according to claim 17, wherein the outdoor heat exchanger has a total area of heat exchange surfaces of the second heat exchanger of the first heat exchanger. The gist is that it is smaller than the total area of the heat exchange surfaces.

  According to this invention, since the total area of the heat exchange surfaces of the second heat exchanger is smaller than the total area of the heat exchange surfaces of the first heat exchanger, the amount of water droplets adhering to the second heat exchanger is reduced. Can be reduced. Therefore, the amount of frost formation on the second heat exchanger can be reduced.

  The invention according to claim 19 is an outdoor heat exchanger in which a coolant is circulated by a heat exchange tube penetrating the plate fin and a coating film having water slidability and water repellency is provided on a heat exchange surface of the plate fin; In the air conditioner including a defrost device that performs a defrost operation on the outdoor heat exchanger, the outdoor heat exchanger includes a first fin provided as a part of the plate fin, and the first fin A first heat exchanger configured to include a first tube as the heat exchange tube penetrating the fin, and provided below the first heat exchanger, as a part of the plate fin A second heat exchanger configured to include a second fin provided below and a second tube as the heat exchange tube penetrating the second fin. And the 1st tube and the 2nd tube are constituted as a mutually independent system, and the interval of the 2nd tubes in the up-and-down direction of the 2nd heat exchanger is the 1st heat exchanger. The gist is that it is set larger than the interval between the first tubes in the vertical direction.

  According to this invention, compared with the space | interval of the 1st tubes of a 1st heat exchanger, it is formed so that the space | interval of the 2nd tubes of a 2nd heat exchanger may become large, 2nd heat In the exchanger, the formation of frost between the second tubes can be suppressed. Therefore, by reducing the frost formation amount of the second heat exchanger, it is possible to suppress the operation of the defrost operation even under the operation conditions of the conventional defrost operation, so that the efficiency of the defrost operation can be improved. it can.

  According to the twentieth aspect of the present invention, in the air conditioner according to any one of the seventeenth to nineteenth aspects, the air conditioner performs a defrost operation on the outdoor heat exchanger. A defrosting device is further provided, and the defrosting device performs the refrigerant control of the first heat exchanger and the refrigerant control of the second heat exchanger individually.

  According to this invention, the outdoor heat exchanger can be efficiently defrosted by separately performing the refrigerant control of the first heat exchanger and the refrigerant control of the second heat exchanger. Therefore, the efficiency of the defrost operation can be increased.

  ADVANTAGE OF THE INVENTION According to this invention, the air conditioner which can raise the efficiency of a defrost driving | operation further can be provided, suppressing the frost formation to a heat exchange surface with the coating film which has water slidability and water repellency.

(First embodiment)
With reference to FIGS. 1-3, 1st Embodiment which actualized the air conditioner of this invention is described.

  As shown in FIG. 1, in the air conditioner 1, the outdoor heat exchanger 2, the expansion valve 3, the indoor heat exchanger 4, the four-way switching valve 5, and the compressor 6 are connected by a refrigerant pipe, A refrigerant circuit is configured. In addition, the air conditioner 1 includes a control device 12 that controls the expansion valve 3, the four-way switching valve 5, and the compressor 6. More specifically, the air conditioner 1 includes two outdoor heat exchangers 2 connected in parallel to each other, and expansion valves 3 arranged at a plurality of positions in the refrigerant pipe are controlled by the control device 12. By being controlled, each outdoor heat exchanger 2 is controlled. That is, each outdoor heat exchanger 2 is operated independently.

  The outdoor heat exchanger 2 includes a heat exchanger upper part 2a and a heat exchanger lower part 2b. The refrigerant pipes of the heat exchanger upper part 2a and the heat exchanger lower part 2b are connected in parallel by being connected to each other at connection points GP1 and GP2.

  The expansion valve 3 includes an upper expansion valve 31, a first lower expansion valve 32, and a second lower expansion valve 33, and is disposed at a plurality of positions in the refrigerant circuit of the air conditioner 1, respectively. That is, the upper expansion valve 31 is provided between the connection point GP1 and the heat exchanger upper part 2a, and the first lower expansion valve 32 is provided between the connection point GP1 and the heat exchanger lower part 2b. The lower expansion valve 33 is provided between the heat exchanger lower part 2b and the connection point GP2.

  The four-way selector valve 5 is connected to the indoor heat exchanger 4 and the outdoor heat exchanger 2, that is, the indoor heat exchanger 4 and the connection point GP2, respectively. Further, the compressor 6 is connected to the four-way switching valve 5 so that the refrigerant is discharged and sucked from the compressor 6. The heat exchanger upper part 2a and the heat exchanger lower part 2b are connected in parallel, and the heat exchanger upper part 2a is provided with an upper expansion valve 31 and the heat exchanger lower part 2b is provided with a first lower expansion valve 32, respectively. Thereby, the heat exchanger upper part 2a and the heat exchanger lower part 2b are each independently operated. That is, the upper expansion valve 31 and the first lower expansion valve 32 are respectively controlled by the control device 12, whereby the heat exchanger upper part 2a and the heat exchanger lower part 2b are independently operated. The control device 12 controls the following operation of the air conditioner 1 by controlling the expansion valve 3, the four-way switching valve 5, and the compressor 6.

Next, the operation of the air conditioner 1 will be described. The air conditioner 1 performs heating operation, cooling operation, forward cycle defrost operation, and reverse cycle defrost operation.
In the heating operation, the four-way switching valve 5 is set on the broken line side in FIG. In the state of this four-way switching valve 5, the refrigerant discharged from the compressor 6 is the broken line side of the four-way switching valve 5, the indoor heat exchanger 4, the upper expansion valve 31, the first lower expansion valve 32, the outdoor heat. It circulates in the order of the broken line side of the exchanger 2, the second lower expansion valve 33, and the four-way switching valve 5 and is sucked into the compressor 6. By such circulation of the refrigerant, the indoor heat exchanger 4 operates as a condenser, and the outdoor heat exchanger 2 operates as an evaporator. Here, in the indoor side heat exchanger 4 that operates as a condenser, the refrigerant exchanges heat with the indoor air and condenses, whereby the refrigerant radiates heat to the indoor air. In the outdoor heat exchanger 2 that operates as an evaporator, the refrigerant exchanges heat with outdoor air and evaporates, whereby the refrigerant absorbs heat from the outdoor air.

  In the cooling operation, the four-way switching valve 5 is set on the solid line side in FIG. In the state of the four-way switching valve 5, the refrigerant that is the heat medium discharged from the compressor 6 is the solid line side of the four-way switching valve 5, the second lower expansion valve 33, the outdoor heat exchanger 2, and the upper expansion valve 31. And it circulates in order of the continuous line side of the 1st lower expansion valve 32, the indoor side heat exchanger 4, and the four-way selector valve 5, and is suck | inhaled by the compressor 6. FIG. By such circulation of the refrigerant, the outdoor heat exchanger 2 operates as a condenser, and the indoor heat exchanger 4 operates as an evaporator. Here, in the outdoor heat exchanger 2, the refrigerant exchanges heat with the outdoor air and condenses, whereby the refrigerant radiates heat to the outdoor air. In the indoor heat exchanger 4, the refrigerant exchanges heat with the indoor air and evaporates, whereby the indoor air is absorbed by the refrigerant and cooled.

  In the normal cycle defrost operation, the four-way switching valve 5 is set on the broken line side in FIG. In the state of the four-way switching valve 5, the output of the compressor 6 is reduced and the upper expansion valve 31 and the first lower expansion valve 32, which are the expansion valves 3, are fully opened. The indoor fan is controlled to rotate at a low speed. On the other hand, the outdoor fan is operated similarly to the heating operation. Here, the control device 12 controls the four-way switching valve 5, the compressor 6, the upper expansion valve 31, and the first lower expansion valve 32, thereby defrosting the outdoor heat exchanger 2 to the air conditioner 1. The device is configured.

  In this forward cycle defrost operation, defrost is performed while continuing the heating function. That is, the refrigerant discharged from the compressor 6 in a low pressure state as compared with the heating operation heats the indoor air by exchanging heat with the indoor air in the indoor heat exchanger 4 and Condense. The refrigerant that has passed through the indoor heat exchanger 4 flows to the heat exchanger upper part 2a and the heat exchanger lower part 2b of the outdoor heat exchanger 2 through the upper expansion valve 31 and the first lower expansion valve, respectively. . At this time, due to the refrigerant flowing respectively in the heat exchanger upper part 2a and the heat exchanger lower part 2b, water droplets adhering to the surface of the plate fin which is the heat exchange surface of the outdoor heat exchanger 2 are frozen to form ice and frost. In addition to being suppressed, the ice and frost already formed on the surface of the plate fins are melted.

  In the reverse cycle defrost operation, the four-way selector valve 5 is set to the solid line side in FIG. In the state of the four-way switching valve 5, the output of the compressor 6 is improved and the second lower expansion valve 33 which is the expansion valve 3 is fully opened. And an outdoor fan and an indoor fan each stop. Here, when the control device 12 controls the four-way switching valve 5, the compressor 6, and the second lower expansion valve 33, a defrost device that defrosts the outdoor heat exchanger 2 in the air conditioner 1 is configured.

  In the reverse cycle defrost operation, the refrigerant circulation direction is reversed as compared with the refrigerant circulation direction during the heating operation. That is, the refrigerant discharged from the compressor 6 is the solid line side of the four-way switching valve 5, the outdoor heat exchanger 2, the expansion valve 3 (second lower thermal expansion valve 33), the indoor heat exchanger 4, and the four-way switching. It circulates in the order of the solid line side of the valve 5 and is sucked into the compressor 6.

  More specifically, the high-temperature refrigerant discharged from the compressor 6 flows to the outdoor heat exchanger 2. And the ice and frost adhering to the surface of the plate fin which is a heat exchange surface of the outdoor heat exchanger 2 are melted by the high-temperature refrigerant. The refrigerant that has passed through the outdoor heat exchanger 2 flows into the indoor heat exchanger 4 and is then sucked into the compressor 6 through the solid line side of the four-way switching valve 5. Further, during the reverse cycle defrost operation, the heating operation is stopped.

Next, the structure of the outdoor heat exchanger of the air conditioner of this embodiment will be described.
As shown in FIG. 2, the outdoor heat exchanger 2 of the air conditioner is configured as a so-called cross fin tube heat exchanger. Specifically, the outdoor heat exchanger 2 has a plurality of plate fins 22 in which the heat exchange surfaces 21 that exchange heat with the outside air are arranged to face each other, that is, a constant interval between the heat exchange surfaces 21. A plurality of plate fins 22 arranged in parallel in a formed state and a heat exchange tube 24 penetrating the plurality of plate fins 22 in the arrangement direction of the plate fins 22 are configured. The space formed between the plate fins 22 forms a passage through which air flows, and heat exchange is performed between the air and the refrigerant on the heat exchange surface 21 by the air passing through the passage. Hereinafter, the air flow direction between the plate fins 22 is referred to as an air flow direction V. The heat exchange tube 24 includes a first tube 241 provided on the fin upper portion 221 of the plate fin 22 and a second tube 242 provided on the fin lower portion 222 of the plate fin 22. Here, the heat exchanger upper part 2 a is configured by the fin upper part 221 and the first tube 241. The fin lower part 222 and the second tube 242 constitute a heat exchanger lower part 2b. In the present embodiment, the heat exchange surface 21 is a surface of each plate fin 22 on which a hole for inserting the heat exchange tube 24 is formed.

  In the outdoor heat exchanger 2, the plate fins 22 are arranged such that the longitudinal direction is parallel to the vertical direction. In the plate fins 22, one row of fin rows arranged along the arrangement direction of the plate fins 22 is arranged along the air circulation direction V. Moreover, since the coating film which has water slidability and water repellency is formed in the surface of the plate fin 22, water slidability and water repellency are large compared with the heat exchange surface which has not surface-treated. Further, the coating film having water slidability and water repellency formed on the surface of the plate fin 22 has a specific organopolysiloxane which is a silicone oil having a silanol group with respect to 100 parts by weight of the specific organopolysiloxane which is a silicone resin. It is comprised with the composition which contains polysiloxane in the ratio of 3-70 weight part. The plate fins 22 may be any type of fins as long as they are plate-like fins such as flat fins, slit fins, and waffle fins.

  Next, with reference to FIG.1 and FIG.3, control of the defrost driving | operation in the outdoor side heat exchanger 2 of the air conditioner 1 is demonstrated. The following control of the defrost operation is executed during the heating operation of the air conditioner 1.

  As shown in FIG. 3, in step S1, the temperature TH1 (° C.) of the heat exchanger upper portion 2a (hereinafter simply referred to as “temperature TH1”) and the temperature TH2 (° C.) of the heat exchanger lower portion 2b (hereinafter simply referred to as “ Temperature TH2 ") is measured, and it is determined whether or not the temperature is equal to or lower than a predetermined frost start temperature Z (° C). Here, the frost start temperature Z (° C.) is a temperature at which frosting starts on the surface of the plate fin 22 which is the heat exchange surface 21. Further, the temperature TH1 and the temperature TH2 are measured by attaching temperature sensors to the heat exchanger upper part 2a and the heat exchanger lower part 2b, respectively. The air conditioner 1 is provided with a counter that counts the number of forward cycle defrost operations.

  In step S1, when at least one of temperature TH1 and temperature TH2 is equal to or lower than frost start temperature Z (Yes in step S1 in FIG. 3), a counter is initialized (step S2 in FIG. 3). After that, the forward cycle defrost operation is performed only for the heat exchanger lower part 2b (step S3 in FIG. 3). When only the heat exchanger lower part 2b performs the positive cycle defrost operation, the refrigerant supplied from the indoor heat exchanger 4 to the outdoor heat exchanger 2 by fully closing the upper expansion valve 31 shown in FIG. It is supplied only to the heat exchanger lower part 2b. As a result, ice and frost adhering to the heat exchanger lower part 2b, that is, the fin lower part 222 (see FIG. 2) are melted. The refrigerant that has passed through the heat exchanger lower part 2 b becomes a gas refrigerant by the second lower expansion valve 33 and is sucked into the compressor 6.

  On the other hand, if at least one of the temperature TH1 and the temperature TH2 is higher than the frost start temperature Z in step S1 (No in step S1 in FIG. 3), the outdoor heat exchanger 2 is not frosted, or It is determined that the frost formation on the outdoor heat exchanger 2 has no significant effect on the decrease in heat exchange capacity, and the defrost operation is not performed.

  In step S3, after the forward cycle defrost operation is performed on the heat exchanger lower part 2b, the temperature TH2 is measured again to determine whether the temperature TH2 is equal to or lower than the frost start temperature Z (step S4 in FIG. 3).

  In step S4, when the temperature TH2 is higher than the frost start temperature Z (No in step S4 in FIG. 3), the outdoor heat exchanger 2 is not frosted or the frost formation of the outdoor heat exchanger 2 is hot. It is determined that there is no significant effect on the reduction of the exchange capacity, and the defrost operation is not performed again.

  On the other hand, if the temperature TH2 is equal to or lower than the frost start temperature Z in step S4 (Yes in step S4 in FIG. 3), the counter counts (step S5 in FIG. 3). Then, it is determined whether the count number of the counter is a predetermined count number (hereinafter referred to as “predetermined value”) (step S6 in FIG. 3). That is, it is determined whether or not the normal cycle defrost operation has been performed a predetermined number of times. In this embodiment, the count number is 3.

  In step S6, when the count number of the counter is smaller than the predetermined value (No in step S6 in FIG. 3), the process returns to step S3, and the forward cycle defrost operation is performed again on the heat exchanger lower part 2b.

  On the other hand, if the count value of the counter is a predetermined value in step S6 (Yes in step S6 in FIG. 3), the reverse heat defrost operation is performed on the outdoor heat exchanger 2 (step S7 in FIG. 3). That is, when the count number of the counter reaches a predetermined value, it is determined that the outdoor heat exchanger 2 cannot be efficiently defrosted only by performing the positive cycle defrost operation only on the heat exchanger lower part 2b, and the heat exchanger upper part 2a And a reverse cycle defrost driving | operation is performed with respect to the heat exchanger lower part 2b. Compared with the normal cycle defrost operation, the reverse cycle defrost operation can reduce the amount of frost formation on the surface of the plate fins 22 because the temperature of the refrigerant supplied to the outdoor heat exchanger 2 is high. Note that the control of the defrost operation is repeatedly executed at a constant cycle. Further, with the above-described control configuration, the reverse cycle defrost operation is performed in both the heat exchanger upper part 2a and the heat exchanger lower part 2b, but the heat exchanger upper part 2a is not subjected to the normal cycle defrost operation and is not in the heat exchanger lower part. Since the positive cycle defrost operation is performed only on 2b, the defrost capability of the defrost operation on the heat exchanger upper portion 2a is higher than the defrost capability of the defrost operation on the heat exchanger lower portion 2b.

According to the air conditioner 1 of the present embodiment, the following effects can be achieved.
(1) In the air conditioner 1 of this embodiment, the heat exchanger upper part 2a and the heat exchanger lower part 2b are systems independent of each other, and refrigerant control for the first tube and refrigerant control for the second tube are performed separately. In addition, the defrost capability of the defrost operation for the heat exchanger upper portion 2a is set to be smaller than the defrost capability of the defrost operation for the heat exchanger lower portion 2b. According to this configuration, the defrost operation can be performed on the upper and lower portions of the outdoor heat exchanger 2, that is, the fin upper portion 221 and the fin lower portion 222 of the plate fin 22, respectively. It is possible to improve the degree of freedom of control of the defrost operation performed on. Therefore, as compared with the heat exchanger upper part 2a, only the heat exchanger lower part 2b having a large amount of frost formation can be defrosted, and the formation of ice and frost can be suppressed in the fin lower part 222. Accordingly, since the defrosting operation can be performed only for the fin lower part 222, the time for the defrosting operation per time is reduced as compared with the case where the defrosting operation is performed for both the fin upper part 221 and the fin lower part 222. Can do. As a result, it is possible to suppress a decrease in the capacity of the air conditioner associated with the defrost operation.

  (2) Further, in the air conditioner 1 of the present embodiment, the outdoor heat exchanger 2, that is, the heat exchanger upper part 2a and the heat exchanger, until the positive cycle defrost operation of the heat exchanger lower part 2b reaches a predetermined number of times. The lower 2b has a control configuration in which the reverse cycle defrost operation is not performed. According to this structure, since the frequency | count of execution of the defrost operation of the heat exchanger upper part 2a decreases compared with the execution frequency of the defrost operation of the heat exchanger lower part 2b, that is, compared with the heat exchanger lower part 2b, Since the frequency | count of execution of the defrost operation of the heat exchanger upper part 2a with little frost formation amount can be reduced, the efficiency of a defrost operation can be improved. In other words, since it is located at the fin lower part 222 and the defrost operation is performed more on the heat exchanger lower part 2b where frost is more easily formed than the heat exchanger upper part 2a, The formation of frost can be suppressed. In particular, it is possible to suppress the reverse cycle defrost operation in the entire outdoor heat exchanger 2 by repeating the forward cycle defrost operation in the heat exchanger lower part 2b. As a result, since it is possible to suppress the reverse cycle defrost operation in which the degree of decrease in the capacity of the air conditioner 1 is significantly lower than that in the normal cycle defrost operation, the degree of decrease in the capacity of the air conditioner 1 associated with the defrost operation is suppressed. be able to.

  (3) In the air conditioner 1 of this embodiment, it is set as the control structure which performs a defrost operation, ie, a normal cycle defrost operation, only with respect to the heat exchanger lower part 2b. According to this configuration, the defrosting operation, that is, the positive cycle defrosting operation is performed only on the heat exchanger lower part 2b having a large amount of frost compared to the heat exchanger upper part 2a. Frost growth and frost formation can be easily suppressed. Therefore, the efficiency of the defrost operation can be increased as compared with the case where the forward cycle defrost operation is performed on both the heat exchanger upper part 2a and the heat exchanger lower part 2b. Moreover, since the defrost of the outdoor heat exchanger 2 may be surely performed only by the forward cycle defrost operation of only the heat exchanger lower part 2b, the reverse cycle defrost operation is performed in the entire outdoor heat exchanger 2. Can be suppressed. That is, the number of executions of the reverse cycle defrost operation can be reduced in the entire outdoor heat exchanger 2. As a result, since it is possible to suppress the reverse cycle defrost operation in which the degree of decrease in the capacity of the air conditioner 1 is significantly lower than that in the normal cycle defrost operation, the degree of decrease in the capacity of the air conditioner 1 associated with the defrost operation is suppressed. be able to. Further, when the heat exchanger upper part 2a is not frosted or when the heat exchanger upper part 2a has a very small amount of frost formation, the heat exchanger upper part 2a is operated in the normal cycle defrost operation or the reverse cycle defrost operation. Therefore, the efficiency of defrosting operation can be increased.

(Second Embodiment)
With reference to FIG. 4, 2nd Embodiment which actualized the air conditioner of this invention is described. In addition, since the air conditioner of this embodiment and the air conditioner of 1st Embodiment differ only in control of a defrost operation, the description is abbreviate | omitted using the same code | symbol for the same component. .

  As shown in FIG. 4, in step S10, first, the temperature TH2 (t) (° C.) of the heat exchanger lower part 2b of the outdoor heat exchanger 2 is measured, and the heat exchanger lower part 2b is measured at regular intervals. The difference between the calculated temperature TH2 (t-1) (° C.) and the temperature TH2 (t) is calculated. Then, it is determined whether or not the difference between the temperature TH2 (t−1) and the temperature TH2 (t) is equal to or greater than a threshold value X (° C.). Here, the temperature TH2 (t-1) is a temperature measured immediately before the temperature TH2 (t) is measured in a certain period.

  At this time, if the value of the difference between the temperature TH2 (t-1) and the temperature TH2 (t) is smaller than the threshold value X (No in step S10 in FIG. 4), frost is not formed in the heat exchanger lower part 2b. judge. In this embodiment, the threshold value X is about 2 ° C. On the other hand, when the value of the difference between the temperature TH2 (t-1) and the temperature TH2 (t) is equal to or greater than the threshold value X (Yes in step S10 in FIG. 4), frost is formed in the heat exchanger lower part 2b. judge. Then, the process proceeds to step S11.

  In step S11, the temperature TH1 (t) (° C.) of the heat exchanger upper part a of the outdoor heat exchanger 2 is measured, and the temperature TH1 (t−1) measured for the heat exchanger upper part 2a at regular intervals. The difference between (° C.) and the temperature TH1 (t) is calculated. Then, it is determined whether or not the difference between the temperature TH1 (t-1) and the temperature TH1 (t) is equal to or greater than a threshold Y (° C.). Here, the temperature TH1 (t-1) is a temperature measured immediately before the temperature TH1 (t) is measured in a certain period.

  At this time, if the value of the difference between the temperature TH1 (t-1) and the temperature TH1 (t) is smaller than the threshold Y (No in step S11 in FIG. 4), frost is not formed on the heat exchanger upper part 2a. judge. In the present embodiment, the threshold Y is about 5 ° C. In this case, since it is determined from steps S10 and S11 that frost is formed only in the heat exchanger lower part 2b, the forward cycle defrost operation is performed only in the heat exchanger lower part 2b (step S12 in FIG. 4).

  After the forward cycle defrost operation is performed on the heat exchanger lower part 2b, the temperature TH2 of the heat exchanger lower part 2b is measured. And it is determined whether temperature TH2 is more than frost start temperature Z (degreeC) (step S13 of FIG. 4).

  In step S13, when the temperature TH2 is equal to or higher than the frost start temperature Z (° C.) (Yes in step S13 in FIG. 4), the defrost operation is not performed. On the other hand, when the temperature TH2 is lower than the frost start temperature Z (No in step S13 in FIG. 4), the forward cycle defrost operation is performed again on the heat exchanger lower part 2b.

  In step S11, when the value of the difference between the temperature TH1 (t-1) and the temperature TH1 (t) is equal to or greater than the threshold Y (Yes in step S11 in FIG. 4), the upper part of the heat exchanger is obtained from steps S10 and S11. Since it is determined that frost is formed on both 2a and the lower heat exchanger 2b, the reverse cycle defrosting operation is performed on the upper heat exchanger 2a and the lower heat exchanger 2b (step S14 in FIG. 4). Note that the control of the defrost operation is repeatedly executed at a constant cycle. Further, with the above-described control configuration, the reverse cycle defrost operation is performed in both the heat exchanger upper part 2a and the heat exchanger lower part 2b, but the heat exchanger upper part 2a is not subjected to the normal cycle defrost operation and is not in the heat exchanger lower part. Since the positive cycle defrost operation is performed only on 2b, the defrost capability of the defrost operation on the heat exchanger upper portion 2a is higher than the defrost capability of the defrost operation on the heat exchanger lower portion 2b.

In addition, according to the air conditioner 1 of the 2nd Embodiment of this invention, in addition to the effect (1) of 1st Embodiment, there can exist the following effects.
(4) In the outdoor heat exchanger 2 in which a coating having water slidability and water repellency is provided on the heat exchange surface 21, the amount of frost on the heat exchanger lower portion 2b is larger than that of the heat exchanger upper portion 2a. The heat exchanger upper part 2a is not frosted, but only the heat exchanger lower part 2b is frosted. When only such a heat exchanger lower part 2b is frosted, in the air conditioner 1 of this embodiment, regardless of the temperature difference of the heat exchanger upper part 2a, the temperature difference of the heat exchanger lower part 2b is a predetermined condition ( In the case of the threshold value X or more), only the heat exchanger lower part 2b is defrosted because only the heat exchanger lower part 2b is subjected to the positive cycle defrosting operation. Therefore, there are cases where the defrost of the outdoor heat exchanger 2 can be surely performed only by the forward cycle defrost operation of only the heat exchanger lower part 2b. Therefore, the reverse cycle defrost operation is performed in the entire outdoor heat exchanger 2. Can be suppressed. That is, the number of executions of the reverse cycle defrost operation can be reduced in the entire outdoor heat exchanger 2. As a result, it is possible to suppress the degree of decrease in the capacity of the air conditioner 1 associated with the positive cycle defrost operation. Further, when the heat exchanger upper part 2a is not frosted or when the heat exchanger upper part 2a has a very small amount of frost formation, the heat exchanger upper part 2a is operated in the normal cycle defrost operation or the reverse cycle defrost operation. Therefore, the efficiency of defrosting operation can be increased.

(Third embodiment)
With reference to FIG. 5, 3rd Embodiment which actualized the air conditioner of this invention is described. In addition, since the air conditioner of this embodiment and the air conditioner of 1st Embodiment differ only in the structure of the outdoor heat exchanger 2, it uses the same code | symbol for the same component, Description is omitted.

  As shown in FIG. 5, a part of the plate fin 22 of the heat exchanger lower part 2b of the outdoor heat exchanger 2 is cut. That is, the fin pitch P2 of the plate fins 22 of the fin lower portion 222 of the plate fins 22 is formed larger than the fin pitch P1 of the plate fins 22 of the upper fin portion 221 of the plate fins 22. Here, the fin pitch of the plate fins 22 refers to the distance between adjacent plate fins 22 in the arrangement direction of the plate fins 22. In other words, the plate fin 22 has a total area of the fin lower portion 222 which is a heat exchange surface of the heat exchanger lower portion 2b, more than a total area of the fin upper portion 221 which is a heat exchange surface of the heat exchanger upper portion 2a. It is formed to be smaller.

According to the air conditioner 1 of the 3rd Embodiment of this invention, there can exist the following effects.
(1) In the air conditioner 1 of the present embodiment, the plate fins of the fin lower portion 222 of the plate fin 22 are compared with the fin pitch P1 of the plate fin 22 of the fin upper portion 221 of the plate fin 22 of the outdoor heat exchanger 2. The fin pitch P2 of 22 is formed to be large. According to this configuration, in the arrangement direction of the plate fins 22, the distance between the adjacent fin upper portions 221 is larger than the distance between the adjacent fin lower portions 222. Heat exchange capacity is reduced. Accordingly, since the amount of water droplets adhering to the fin lower portion 222 is reduced as compared with the amount of water droplets adhering to the fin upper portion 221, the frosting amount of the fin lower portion 222 can be reduced.

  (2) In particular, in the arrangement direction of the plate fins 22, the distance between the adjacent fin upper parts 221 is larger than the distance between the adjacent fin lower parts 222. , It is possible to suppress frost from being connected between adjacent fin lower portions 222. Therefore, the amount of frost that grows from the fin lower portion 222 to the fin upper portion 221 can be suppressed.

  (3) In addition, the plate fin 22 is formed so that the total area of the fin lower part 222 is smaller than the total area of the fin upper part 221, so that it is compared with the amount of water droplets adhering to the fin upper part 221. The amount of water droplets adhering to the fin lower portion 222 can be reduced. Therefore, compared with the fin upper part 221, the amount of frost formation of the fin lower part 222 can be reduced.

(Fourth embodiment)
With reference to FIG. 6, 4th Embodiment which actualized the air conditioner of this invention is described. In addition, since the air conditioner of this embodiment and the air conditioner of 1st Embodiment differ only in the structure of the outdoor heat exchanger 2, the description is abbreviate | omitted using the same code | symbol for the same component. .

  As shown in FIG. 6, in the outdoor heat exchanger 2, the pitch P4 of the second tubes 242 of the heat exchanger lower part 2b is larger than the pitch P3 of the first tubes 241 of the heat exchanger upper part 2a. Is formed. Here, the pitch of the heat exchange tubes refers to the distance between the portions passing through the plate fins 22 of the adjacent heat exchange tubes in the vertical direction of the outdoor heat exchanger 2 shown in FIG.

According to the air conditioner of the present embodiment, in addition to the same effects as the effect (1) of the air conditioner of the third embodiment, the following effects can be achieved.
(4) In the air conditioner 1 of the present embodiment, the pitch P4 of the second tubes 242 is larger than the pitch P3 of the first tubes 241. According to this configuration, when frost is formed in the fin lower part 222, the pitch of the second tube 242 is higher than the pitch P3 of the first tube 241 in the vertical direction of the outdoor heat exchanger 2 shown in FIG. It can suppress that frost connects between P4. Therefore, the amount of frost that grows from the fin lower portion 222 to the fin upper portion 221 can be suppressed.

(Fifth embodiment)
With reference to FIG. 7, 5th Embodiment which actualized the air conditioner of this invention is described. Note that the air conditioner of the present embodiment and the air conditioner of the first embodiment differ only in the configuration of the refrigerant circuit, and the structure of the outdoor heat exchanger is the same, so the same components are the same. The description will be omitted using reference numerals. In addition, the same reference numerals are used for the same components of the refrigerant circuit of the air conditioner, and the description thereof is omitted, and only differences from the refrigerant circuit of the first embodiment will be described.

  As shown in FIG. 7, in the air conditioner 1, the connection point GP <b> 3 between the four-way switching valve 5 and the indoor heat exchanger 4, and between the heat exchanger lower part 2 b and the first lower expansion valve 32. A bypass circuit 7 connecting the connection points GP4 is formed. The bypass circuit 7 is provided with an electromagnetic valve 71. In addition, a check valve 8 and a capillary tube 9 are provided between the heat exchanger lower part 2b and the connection point GP2 so as to be connected in parallel with a refrigerant pipe connecting the heat exchanger lower part 2b and the connection point GP2. By these check valve 8 and capillary tube 9, the refrigerant that has passed through the heat exchanger lower part 2b is decompressed. The control device 12 controls the following operation of the air conditioner 1 by controlling the upper expansion valve 31, the first lower expansion valve 32, the four-way switching valve 5, the compressor 6, and the electromagnetic valve 71. To do.

Next, each operation of the air conditioner 1 will be described.
In the heating operation, the air conditioner 1 fully closes the electromagnetic valve 71 and the check valve 8. As a result, the high-pressure refrigerant discharged from the compressor 6 does not pass through the bypass circuit 7 and is supplied to the indoor heat exchanger 4, and the refrigerant that has passed through the heat exchanger lower part 2 b does not pass through the capillary tube 9. , Supplied to the connection point GP2. Thereby, the heating operation similar to the refrigerant circuit of 1st Embodiment is performed.

  In the cooling operation, the air conditioner 1 fully closes the electromagnetic valve 71. Further, since the check valve 8 is provided, the refrigerant discharged from the compressor 6 is not supplied to the heat exchanger lower part 2b via the capillary tube 9, that is, discharged from the compressor 6. The refrigerant is directly supplied to the heat exchanger lower part 2b. Thereby, the cooling operation similar to the refrigerant circuit of 1st Embodiment is performed.

  In the normal cycle defrost operation, particularly in the positive cycle defrost operation with only the heat exchanger lower part 2b, the electromagnetic valve 71 is fully opened. As a result, the high-pressure refrigerant discharged from the compressor 6 is supplied to the indoor heat exchanger 4 and the bypass circuit 7. Here, the super expansion control is performed on the upper expansion valve 31 to decompress the refrigerant that has passed through the indoor heat exchanger 4.

  And the refrigerant | coolant which passed the indoor side heat exchanger 4 is supplied to the heat exchanger upper part 2a in the state decompressed by the upper expansion valve 31. FIG. The refrigerant supplied to the bypass circuit 7 passes through the electromagnetic valve 71 and is supplied to the heat exchanger lower part 2b. Therefore, the heat exchanger lower part 2b is supplied in the state of the high-pressure refrigerant discharged from the compressor 6. Thereby, the ice and frost adhering to the heat exchanger lower part 2b are melted. Thereby, since the refrigerant | coolant which passed the indoor side heat exchanger 4 is supplied to the heat exchanger upper part 2a, without decompressing, the ice and frost adhering to the heat exchanger upper part 2a are melt | dissolved. In addition, the control device 12 controls the four-way switching valve 5, the compressor 6, the upper expansion valve 31, the first lower expansion valve 32, and the electromagnetic valve 71, so that the outdoor heat exchanger 2 of the air conditioner 1 is controlled. A defrost device that performs a positive cycle defrost operation is configured.

  Here, the forward cycle defrost operation is performed by supplying a part of the high-pressure refrigerant supplied from the compressor 6 to the indoor heat exchanger 4 to the bypass circuit 7 during the heating operation. That is, the forward cycle defrost operation is performed simultaneously with the heating operation.

  In the reverse cycle defrost operation, the air conditioner 1 fully closes the electromagnetic valve 71. Further, since the check valve 8 is provided, the refrigerant discharged from the compressor 6 is not supplied to the heat exchanger lower part 2b via the capillary tube 9, that is, discharged from the compressor 6. The refrigerant is directly supplied to the heat exchanger lower part 2b. Thereby, the reverse cycle defrost operation similar to the refrigerant circuit of the first embodiment is performed. In addition, the control device 12 controls the four-way switching valve 5, the compressor 6, the upper expansion valve 31, the first lower expansion valve 32, and the electromagnetic valve 71, so that the outdoor heat exchanger 2 of the air conditioner 1 is controlled. A defrost device that performs reverse cycle defrost operation is configured.

According to the air conditioner 1 of this embodiment, in addition to the effects (1) to (3) of the first embodiment, the following effects can be achieved.
(4) In the air conditioner 1 of the present embodiment, the connection point GP3 between the four-way switching valve 5 and the indoor heat exchanger 4, and between the heat exchanger lower part 2b and the first lower expansion valve 32 are provided. A bypass circuit 7 that connects the connection points GP4 is formed. According to this configuration, the normal cycle defrosting operation can be performed on the heat exchanger lower part 2b by the bypass circuit 7 even while the air conditioner 1 is performing the heating operation. That is, the air conditioner 1 can simultaneously perform the heating operation and the normal cycle defrost operation. Accordingly, it is possible to suppress a decrease in indoor heating comfort sensitivity and to defrost the outdoor heat exchanger 2.

  (5) Particularly, since the control configuration of the defrost operation of the present embodiment is the same as the control configuration of the defrost operation of the first embodiment, the defrost capability of the defrost operation with respect to the heat exchanger upper part 2a is the lower part of the heat exchanger. It is set to be smaller than the defrost capability of the defrost operation for 2b. Therefore, since the frequency with which the reverse cycle defrost operation is performed is low, the defrost of the outdoor heat exchanger 2 can be performed while continuing the heating operation.

(Sixth embodiment)
With reference to FIG. 8, 6th Embodiment which actualized the air conditioner of this invention is described. Note that the air conditioner of the present embodiment and the air conditioner of the first embodiment differ only in the configuration of the refrigerant circuit, and the structure of the outdoor heat exchanger is the same, so the same components are the same. The description will be omitted using reference numerals. In addition, the same reference numerals are used for the same components of the refrigerant circuit of the air conditioner, and the description thereof is omitted, and only differences from the refrigerant circuit of the first embodiment will be described.

  As shown in FIG. 8, in the air conditioner 1, a connection point GP5 between the heat exchanger lower part 2b and the connection point GP2 and a connection point GP6 between the upper expansion valve 31 and the heat exchanger upper part 2a are connected. A bypass circuit 10 is provided. The bypass circuit 10 is provided with an intermediate expansion valve 11. Further, an electromagnetic valve 34 is provided between the connection point GP5 and the connection point GP2 instead of the second lower expansion valve 33 of the first embodiment. The control device 12 controls the intermediate expansion valve 11, the upper expansion valve 31, the first lower expansion valve 32, the four-way switching valve 5, the compressor 6, and the electromagnetic valve 34, so that Controls the operation of

Next, each operation of the air conditioner 1 will be described.
In the heating operation, the air conditioner 1 closes the intermediate expansion valve 11 and opens the electromagnetic valve 34 by a predetermined amount. Thereby, the refrigerant that has passed through the heat exchanger lower part 2b is not supplied to the heat exchanger upper part 2a via the bypass circuit 10, that is, the refrigerant that has passed through the heat exchanger lower part 2b is connected to the connection point GP2. , It merges with the refrigerant that has passed through the heat exchanger upper part 2a. Thereby, the heating operation similar to the refrigerant circuit of 1st Embodiment is performed.

  In the cooling operation, the air conditioner 1 closes the intermediate expansion valve 11. Thereby, the refrigerant discharged from the compressor 6 is not supplied to the upper expansion valve 31 via the bypass circuit 10. That is, the refrigerant that has passed through the electromagnetic valve 34 merges with the refrigerant that has passed through the heat exchanger upper portion 2a and the upper expansion valve 31 at the connection point GP1 via the heat exchanger lower portion 2b and the first lower expansion valve 32. Thereby, the cooling operation similar to the refrigerant circuit of 1st Embodiment is performed.

  In the normal cycle defrost operation, particularly the positive cycle defrost operation with only the heat exchanger lower part 2b, the air conditioner 1 fully closes the electromagnetic valve 34 and performs superheat control on the intermediate expansion valve 11. The first lower expansion valve 32 and the intermediate expansion valve 11 are configured so that the pressure of the refrigerant that has passed through the first lower expansion valve 32 and the pressure of the refrigerant that has passed through the intermediate expansion valve 11 are substantially equal at the connection point GP6. Be controlled.

  And the refrigerant | coolant which passed the indoor side heat exchanger 4 is supplied to the heat exchanger upper part 2a and the heat exchanger lower part 2b via the upper expansion valve 31 and the 1st lower expansion valve 32, respectively. In addition, the refrigerant that has passed through the heat exchanger lower part 2b is supplied to the connection point GP6 via the intermediate expansion valve 11 of the bypass circuit 10, and merges with the refrigerant that has passed through the upper expansion valve 31 to form the upper part of the heat exchanger. 2a. Thereby, the ice and frost adhering to the heat exchanger lower part 2b are melted. In the case where the heat exchanger upper part 2a is simultaneously subjected to the positive cycle defrost operation, the air conditioner 1 fully closes the intermediate expansion valve 11 and fully opens the upper expansion valve 31 and the electromagnetic valve 34. Thereby, the ice and frost adhering to the heat exchanger upper part 2a are melted. Further, the control device 12 controls the four-way switching valve 5, the compressor 6, the intermediate expansion valve 11, the upper expansion valve 31, the first lower expansion valve 32, and the electromagnetic valve 34, so that the outdoor side of the air conditioner 1 is controlled. The heat exchanger 2 is configured with a defrost device that performs a positive cycle defrost operation.

  In the reverse cycle defrost operation, the air conditioner 1 fully opens the electromagnetic valve 34 and fully closes the intermediate expansion valve 11. As a result, the refrigerant that has passed through the electromagnetic valve 34 is not supplied to the upper expansion valve 31 via the bypass circuit 10, that is, the refrigerant that has passed through the electromagnetic valve 34 is the heat exchanger lower portion 2b and the first It is supplied to the connection point GP1 through the lower expansion valve 32. Thereby, the reverse cycle defrost operation similar to the refrigerant circuit of the first embodiment is performed. Further, the control device 12 controls the four-way switching valve 5, the compressor 6, the intermediate expansion valve 11, the upper expansion valve 31, the first lower expansion valve 32, and the electromagnetic valve 34, so that the outdoor side of the air conditioner 1 is controlled. The heat exchanger 2 is configured with a defrost device that performs a reverse cycle defrost operation. In addition, according to this embodiment, there can exist an effect similar to 1st Embodiment.

(Other variations)
In addition, the embodiment of the present invention is not limited to the embodiment exemplified in each of the above embodiments, and can be changed as follows, for example.

  In the air conditioner 1 of the present invention, the fin upper part 221 and the fin lower part 222 of the plate fin 22 are connected, that is, the fin upper part 221 and the fin lower part 222 are configured as a single unit, but the present invention is not limited to this. It will never be done. For example, the fin upper part 221 and the fin lower part 222 may be separated by an alternate long and short dash line in FIGS. 2B, 5 and 6, that is, the fin upper part 221 and the fin lower part 222 may be separate members. In this case, the heat exchanger upper part comprised by the fin upper part 221 and the 1st tube turns into a 1st heat exchanger. Moreover, the heat exchanger lower part comprised with the fin lower part 222 and the 2nd tube turns into a 2nd heat exchanger.

  In the air conditioner 1 of the present invention, the forward cycle defrost operation is performed only on the heat exchanger lower part 2b, but the present invention is not limited to this, and can be modified as follows. That is, instead of performing the forward cycle defrost operation only on the heat exchanger lower part 2b, the reverse cycle defrost operation may be performed only on the heat exchanger lower part 2b. Further, the forward cycle defrosting operation may be performed not only on the heat exchanger lower part 2b but also on the heat exchanger upper part 2a. In this case, the defrost operation may be set as follows. That is, the refrigerant flow rate when performing the defrost operation on the heat exchanger upper part 2a (that is, the amount of refrigerant flowing per unit time) is smaller than the refrigerant flow rate when performing the defrost operation on the heat exchanger lower part 2b. By doing so, the defrost capability of the heat exchanger upper part 2a may be set smaller than the defrost capability of the heat exchanger lower part 2b. Further, the number of executions of the defrost operation of the heat exchanger upper part 2a may be reduced as compared with the number of executions of the defrost operation of the heat exchanger lower part 2b. Moreover, you may make execution time per time of defrost operation with respect to the heat exchanger upper part 2a shorter than execution time per time of defrost operation with respect to the heat exchanger lower part 2b.

  In the air conditioner 1 of the present invention, a cross fin and tube type is used as the outdoor heat exchanger 2, but the present invention is not limited to this. Other embodiments may be used as long as the refrigerant is circulated by a heat exchange tube penetrating the plate fins 22.

  -In the air conditioner 1 of the 3rd Embodiment of this invention, as shown in 3rd Embodiment, as the means to reduce the heat exchange capability of the heat exchanger lower part 2b, the plate fin 22 of the heat exchanger upper part 2a is shown. The fin pitch P2 of the plate fins 22 of the heat exchanger lower part 2b is made larger than the fin pitch P1 of the heat exchanger, or the pitch P3 of the first tubes 241 of the heat exchanger upper part 2a as shown in the fourth embodiment. The pitch P4 of the second tubes 242 of the heat exchanger lower part 2b is increased as compared with the above, but may be modified as follows, for example. That is, as means for reducing the heat exchange capability of the heat exchanger lower part 2b, the fin pitch P1 and the fin pitch P2, and the pitch P3 and the pitch P4 are made equal to each other and compared with the flow rate of the refrigerant flowing through the first tube 241. Then, the flow rate of the refrigerant flowing through the second tube 242 may be reduced.

  -In the air conditioner 1 of the 3rd Embodiment of this invention, compared with the fin pitch P1 of the plate fin 22 of the heat exchanger upper part 2a, the fin pitch P2 of the plate fin 22 of the heat exchanger lower part 2b is enlarged. Therefore, although the fin lower portions 222 are alternately cut in the arrangement direction of the plate fins 22, the present invention is not limited to this and may be modified as follows. For example, the number of cuts of the fin lower portion 222 of the third embodiment may be cut more or less. In the third embodiment, the entire fin lower part 222 is cut, but the present invention is not limited to this, and only a part of the fin lower part 222 may be cut. Even in the modified configuration, the same effects as the effects (1) to (3) of the third embodiment can be obtained.

  In the air conditioner 1 of the fourth embodiment of the present invention, each pitch P4 of the second tube 242 is formed larger than the pitch P3 of the first tube 241, but the present invention is limited to this. However, the following changes may be possible. That is, a part of the pitch P4 of the second tube 242 may be formed large. Even in the modified structure, the same effect as the effect (6) of the fourth embodiment can be obtained. Further, in the air conditioner 1 of the fourth embodiment, in the vertical direction of the plate fins 22, the number of portions where the first tubes 241 penetrate the fin upper portions 221, that is, the first direction extending along the arrangement direction of the plate fins 22. The number of parts of one tube 241 is four, and the number of parts of the second tube 242 penetrating the fin lower part 222 is also four. Instead, the second tube 242 penetrates the fin lower part 222. You may set the number of the site | parts to perform less than the number of the site | parts where the 1st tube 241 penetrates the fin upper part 221. FIG. For example, the number of portions where the second tube 242 penetrates the fin lower portion 222 may be two. Even in the modified structure, the same effect as the effect (4) of the fourth embodiment can be obtained.

  In the air conditioner 1 according to the fifth embodiment of the present invention, the check valve 8 and the capillary tube 9 are provided between the heat exchanger lower part 2b and the connection point GP2. For example, the check valve 8 In addition, an expansion valve may be provided in place of the capillary tube 9.

  In the air conditioner 1 according to the fifth embodiment of the present invention, the bypass valve 7 is provided with the electromagnetic valve 71. For example, as shown in FIG. A capillary tube 73 may be provided. In the refrigerant circuit of FIG. 9, in the heating operation, the pressure reduction amount of the capillary tube 73 and the first lower portion are reduced so that the pressure of the refrigerant passed through the capillary tube 73 is smaller than the pressure of the refrigerant passed through the first lower expansion valve 32. The opening degree of the expansion valve 32 is adjusted. Thereby, the refrigerant discharged from the compressor 6 is prevented from being supplied to the heat exchanger lower part 2 b via the bypass circuit 7. The cooling operation, the forward cycle defrost operation, and the reverse cycle defrost operation are performed in the same manner as in the fifth embodiment of the air conditioner 1.

  In the air conditioner 1 according to the sixth embodiment of the present invention, the electromagnetic valve 34 is provided between the heat exchanger lower part 2b and the connection point GP2. However, for example, a three-way valve is provided instead of the electromagnetic valve 34. May be.

The circuit diagram which shows the refrigerant circuit of an air conditioner about 1st Embodiment which actualized the air conditioner of this invention. (A) About the air conditioner of the embodiment, sectional drawing which shows the cross-section which cut the outdoor side heat exchanger in the plane along a heat exchange surface. (B) The front view which shows the front structure of an outdoor side heat exchanger about the embodiment. The flowchart which shows the process sequence about the defrost driving | operation of the air conditioner of the embodiment. The flowchart which shows the process sequence of the defrost driving | operation of an air conditioner about 2nd Embodiment which actualized the air conditioner of this invention. The front view which shows the front structure of an outdoor side heat exchanger about 3rd Embodiment which actualized the air conditioner of this invention. The front view which shows the front structure of an outdoor side heat exchanger about 4th Embodiment which actualized the air conditioner of this invention. The circuit diagram which shows the refrigerant circuit of an air conditioner about 5th Embodiment which actualized the air conditioner of this invention. The circuit diagram which shows the refrigerant circuit of an air conditioner about 6th Embodiment which actualized the air conditioner of this invention. The circuit diagram which shows the refrigerant circuit of an air conditioner about other embodiment concerning the air conditioner of this invention. Sectional drawing which shows the cross-section along the heat exchange surface of a plate fin about the conventional air conditioner.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Air conditioner, 2 ... Outdoor heat exchanger, 2a ... Heat exchanger upper part, 2b ... Heat exchanger lower part, 8 ... Check valve, 9 ... Capillary tube, 10 ... Bypass circuit, 11 ... Intermediate expansion valve, DESCRIPTION OF SYMBOLS 12 ... Control apparatus, 21 ... Heat exchange surface, 22 ... Plate fin, 24 ... Heat exchange tube, 3 ... Expansion valve, 31 ... Upper expansion valve, 32 ... 1st lower expansion valve, 33 ... 2nd lower expansion valve, 34 ... Solenoid valve, 4 ... Indoor heat exchanger, 5 ... Four-way switching valve, 6 ... Compressor, 7 ... Bypass circuit, 71 ... Solenoid valve, 72 ... Check valve, 73 ... Capillary tube, 221 ... Upper part, 222 ... Lower part, 241 ... first tube, 242 ... second tube.

Claims (20)

An outdoor heat exchanger in which a coolant is circulated by a heat exchange tube passing through the plate fin and a coating film having water slidability and water repellency is provided on the heat exchange surface of the plate fin, and the outdoor heat exchanger In an air conditioner including a defrost device that performs defrost operation,
The outdoor heat exchanger includes a fin upper portion located above the plate fin as a part of the plate fin, and a heat exchanger upper portion including the first tube as the heat exchange tube penetrating the fin upper portion. A heat exchanger that is located below the upper part of the exchanger, and includes a lower fin part positioned as a part of the plate fin and a second tube serving as the heat exchange tube passing through the lower fin part. The first tube and the second tube are configured as a system independent from each other, forming a single heat exchanger including the upper portion of the heat exchanger and the lower portion of the heat exchanger. Yes,
The defrost device separately performs refrigerant control at the upper part of the heat exchanger and refrigerant control at the lower part of the heat exchanger, and has the defrosting capability of the defrost operation for the upper part of the heat exchanger in the defrosting operation for the lower part of the heat exchanger. An air conditioner characterized by being made smaller than the defrost ability. In the air conditioner according to claim 1,
The air conditioner characterized in that the defrost device makes the number of executions of the defrost operation for the upper part of the heat exchanger smaller than the number of times of the defrost operation for the lower part of the heat exchanger. In the air conditioner according to claim 1 or 2,
The said defrost apparatus makes the execution time per time of the defrost operation with respect to the said heat exchanger upper part shorter than the execution time per time of the defrost operation with respect to the said heat exchanger lower part. The air conditioner characterized by the above-mentioned. In the air conditioner according to any one of claims 1 to 3,
The defrost device is characterized in that the refrigerant flow rate in the upper part of the heat exchanger during the defrost operation with respect to the upper part of the heat exchanger is made smaller than the refrigerant flow rate in the lower part of the heat exchanger during the defrost operation with respect to the lower part of the heat exchanger. Air conditioner to do. In the air conditioner according to any one of claims 1 to 4,
The defrost device must make the defrost capability of the defrost operation for the upper portion of the heat exchanger smaller than the defrost capability of the defrost operation for the lower portion of the heat exchanger on the condition that the air conditioner is heated. Air conditioner characterized by. In the air conditioner according to claim 1,
The defroster performs a defrost operation only on the lower part of the heat exchanger. In an air conditioner including an outdoor heat exchanger in which a coolant is circulated by a heat exchange tube penetrating a plate fin and a coating film having water slidability and water repellency is provided on a heat exchange surface of the plate fin.
The outdoor heat exchanger includes a fin upper portion located above the plate fin as a part of the plate fin, and a heat exchanger upper portion including the first tube as the heat exchange tube penetrating the fin upper portion. A heat exchanger that is located below the upper part of the exchanger, and includes a lower fin part positioned as a part of the plate fin and a second tube serving as the heat exchange tube passing through the lower fin part. The first tube and the second tube are configured as a system independent from each other, forming a single heat exchanger including the upper portion of the heat exchanger and the lower portion of the heat exchanger. Yes,
The air conditioner characterized in that the heat exchange performance at the lower part of the heat exchanger is set smaller than the heat exchange performance at the upper part of the heat exchanger. In the air conditioner according to claim 6 or 7,
In the outdoor heat exchanger, the total area of the heat exchange surfaces at the lower part of the heat exchanger is smaller than the total area of the heat exchange surfaces at the upper part of the heat exchanger. In an air conditioner including an outdoor heat exchanger in which a coolant is circulated by a heat exchange tube penetrating a plate fin and a coating film having water slidability and water repellency is provided on a heat exchange surface of the plate fin.
The outdoor heat exchanger includes a fin upper portion located above the plate fin as a part of the plate fin, and a heat exchanger upper portion including the first tube as the heat exchange tube penetrating the fin upper portion. A heat exchanger that is located below the upper part of the exchanger, and includes a lower fin part positioned as a part of the plate fin and a second tube serving as the heat exchange tube passing through the lower fin part. The first tube and the second tube are configured as a system independent from each other, forming a single heat exchanger including the upper portion of the heat exchanger and the lower portion of the heat exchanger. Yes,
The air conditioner characterized in that an interval between the second tubes in the vertical direction at the lower part of the heat exchanger is set larger than an interval between the first tubes in the vertical direction at the upper part of the heat exchanger. In the air conditioner according to any one of claims 7 to 9,
The air conditioner further includes a defrost device that performs a defrost operation on the outdoor heat exchanger,
The air conditioner, wherein the defrost device individually performs refrigerant control on the upper part of the heat exchanger and refrigerant control on the lower part of the heat exchanger. An outdoor heat exchanger in which a coolant is circulated by a heat exchange tube passing through the plate fin and a coating film having water slidability and water repellency is provided on the heat exchange surface of the plate fin, and the outdoor heat exchanger In an air conditioner including a defrost device that performs defrost operation,
The outdoor heat exchanger includes a first fin provided above as a part of the plate fin, and a first heat configured as a first tube as the heat exchange tube penetrating the first fin. An exchanger, a second fin provided below the first heat exchanger as a part of the plate fin, and a first heat exchange tube penetrating the second fin. A second heat exchanger configured to include two tubes, and the first tube and the second tube are configured as independent systems,
The defrost device separately performs refrigerant control of the first heat exchanger and refrigerant control of the second heat exchanger, and has the defrosting capability of the defrost operation for the first heat exchanger as the second heat exchanger. An air conditioner characterized in that the air conditioner is smaller than the defrost capability of defrost operation. The air conditioner according to claim 11,
The said defrost apparatus makes the frequency | count of execution of the defrost operation | movement with respect to a said 1st heat exchanger smaller than the frequency | count of execution of the defrost operation | movement with respect to a said 2nd heat exchanger. The air conditioner characterized by the above-mentioned. The air conditioner according to claim 11 or 12,
The air conditioner characterized in that the defrost device makes an execution time per defrost operation for the first heat exchanger shorter than an execution time per defrost operation for the second heat exchanger. . The air conditioner according to any one of claims 11 to 13,
The defrost device makes the refrigerant flow rate of the first heat exchanger during defrost operation for the first heat exchanger smaller than the refrigerant flow rate of the second heat exchanger during defrost operation for the second heat exchanger. An air conditioner characterized by that. The air conditioner according to any one of claims 11 to 14,
The defrost device must make the defrost capability of the defrost operation for the first heat exchanger smaller than the defrost capability for the second heat exchanger on the condition that the air conditioner is heated. A featured air conditioner. The air conditioner according to claim 11,
The defrost device performs a defrost operation only on the second heat exchanger. An air conditioner. An outdoor heat exchanger in which a coolant is circulated by a heat exchange tube passing through the plate fin and a coating film having water slidability and water repellency is provided on the heat exchange surface of the plate fin, and the outdoor heat exchanger In an air conditioner including a defrost device that performs defrost operation,
The outdoor heat exchanger includes a first fin that is provided above as a part of the plate fin, and a first heat that includes the first tube as the heat exchange tube that penetrates the first fin. An exchanger, a second fin provided below the first heat exchanger as a part of the plate fin, and a first heat exchange tube penetrating the second fin. A second heat exchanger configured to include two tubes, and the first tube and the second tube are configured as independent systems,
The air conditioner characterized in that the heat exchange performance of the second heat exchanger is set smaller than the heat exchange performance of the first heat exchanger. The air conditioner according to claim 17,
In the outdoor heat exchanger, the total area of the heat exchange surfaces of the second heat exchanger is smaller than the total area of the heat exchange surfaces of the first heat exchanger. An outdoor heat exchanger in which a coolant is circulated by a heat exchange tube passing through the plate fin and a coating film having water slidability and water repellency is provided on the heat exchange surface of the plate fin, and the outdoor heat exchanger In an air conditioner including a defrost device that performs defrost operation,
The outdoor heat exchanger includes a first fin provided above as a part of the plate fin, and a first heat configured as a first tube as the heat exchange tube penetrating the first fin. An exchanger, a second fin provided below the first heat exchanger as a part of the plate fin, and a first heat exchange tube penetrating the second fin. A second heat exchanger configured to include two tubes, and the first tube and the second tube are configured as independent systems,
The air conditioner characterized in that an interval between the second tubes in the vertical direction of the second heat exchanger is set larger than an interval between the first tubes in the vertical direction of the first heat exchanger. In the air conditioner according to any one of claims 17 to 19,
The air conditioner further includes a defrost device that performs a defrost operation on the outdoor heat exchanger,
The air conditioner characterized in that the defrost device individually performs refrigerant control of the first heat exchanger and refrigerant control of the second heat exchanger.

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