JP7313867B2 - Cooling structure, electrical unit having the same, and outdoor unit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cooling structure, an electrical unit having the same, and an outdoor unit.

2. Description of the Related Art An outdoor unit of an air conditioner having a refrigeration cycle filled with a refrigerant is equipped with an electric circuit such as an inverter circuit for controlling a motor of a compressor and the like. This inverter circuit is generally provided with a power element that generates operating heat. In order to operate this power element in an appropriate temperature environment, means for cooling the power element may be provided.

As a means for cooling, for example, a refrigerant pipe through which a refrigerant flows is brought into thermal contact with the power element via a cooling block or the like, and the power element is cooled by the cold heat of the refrigerant flowing through the refrigerant pipe.

However, if the coolant excessively cools the cooling block, condensation may form on the surface of the cooling block. If water droplets generated by condensation come into contact with power elements and other electrical components, they may cause malfunctions.

For this reason, it is necessary to suppress dew condensation caused by refrigerant cooling. For example, Patent Literature 1 discloses a device that eliminates dew condensation by intentionally causing a boost converter included in a power converter to generate heat.

WO2017/138130

The device disclosed in Patent Document 1 generates heat in the boost converter (more specifically, the reactor of the boost converter), but the boost converter is originally an electrical component that boosts the voltage according to the operating state of the electric motor of the compressor, and is not a component whose main function is heat generation.

For this reason, problems may occur, such as (1) it takes time to raise the temperature because the amount of heat generated is small, (2) heat generation cannot be controlled with good responsiveness, and (3) heat generation control is limited in relation to operating conditions.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cooling structure capable of efficiently heating a heat transfer member to avoid condensation, an electrical unit having the same, and an outdoor unit.

In order to solve the above problems, the cooling structure of the present invention, an electrical unit provided with the same, and an outdoor unit employ the following means.
That is, a cooling structure according to an aspect of the present invention includes: a heat transfer member that constitutes an electric circuit that controls an air conditioner and is in thermal contact with a cooled portion that generates heat during operation; a cooling portion that is in thermal contact with the heat transfer member to cool the heat transfer member; and a heater portion that is functionally independent of the electric circuit and is in thermal contact with the heat transfer member to heat the heat transfer member.

According to the cooling structure according to this aspect, the heat transfer member forms an electric circuit for controlling the air conditioner and is in thermal contact with the cooled portion that generates heat during operation, and the cooling portion is provided in thermal contact with the heat transfer member to cool the heat transfer member. According to this, the cooled portion that generates heat during operation can be cooled by the cooling portion via the heat transfer member. The cooled portion is, for example, a power element provided in an inverter circuit for a compressor that compresses a refrigerant. The heat transfer member is a block made of a material with high thermal conductivity such as aluminum alloy. The cooling unit is, for example, a pipe through which a low-temperature refrigerant that circulates in a refrigeration cycle of an air conditioner flows.
Further, the cooling structure includes a heater portion that heats the heat transfer member by thermally contacting the heat transfer member. According to this, it is possible to avoid the occurrence of dew condensation by raising the temperature of the heat transfer member by the heater part before dew condensation occurs on the heat transfer member due to excessive cooling by the cooling part.
At this time, the heater section is a component whose main function is to generate heat. Therefore, the temperature can be raised immediately. In addition, since the heater section is a component that is functionally independent of the electric circuit that controls the air conditioner, it can be independently controlled without being affected by the control of the compressor or the like. Therefore, control can be performed with good responsiveness, and control can be performed without being affected by the operating conditions of the air conditioner.

Further, in the cooling structure according to an aspect of the present invention, the heater portion is arranged on a surface of the heating region of the heat transfer member, and the portion to be cooled and the cooling portion are arranged on respective surfaces facing each other across the cooling region of the heat transfer member, which is different from the heating region.

According to the cooling structure according to this aspect, the heater portion is arranged on the surface of the heating region of the heat transfer member, and the portion to be cooled and the cooling portion are arranged on respective surfaces facing each other across the cooling region of the heat transfer member, which is different from the heating region. According to this, it is possible to separate the area of the heat transfer member with which the heater section is in thermal contact and the area of the heat transfer member with which the cooled section and the cooling section are in thermal contact.

Further, in the cooling structure according to an aspect of the present invention, the heat transfer member is provided with a heat insulating material that covers the heating area.

According to the cooling structure according to this aspect, the heat transfer member is provided with the heat insulating material so as to cover the heating region. According to this, it is possible to prevent heat transferred from the heater section to the heating area from being radiated from the heat transfer member in the heating area. Therefore, the heat from the heater portion can be efficiently stored in the heat transfer member.

Moreover, in the cooling structure according to an aspect of the present invention, the cross-sectional area of the heat transfer member in the heating region is larger than the cross-sectional area of the heat transfer member in the cooling region.

According to the cooling structure according to this aspect, the cross-sectional area of the heat transfer member in the heating region is made larger than the cross-sectional area of the heat transfer member in the cooling region. According to this, the heat from the heater section is likely to be stored in the heat transfer member in the heating region where the heater section is arranged. In addition, since the heat stored in the heating region moves intensively to the cooling region having a smaller cross-sectional area than the heating region, the heat from the heater can be efficiently transferred to the cooling region.

An electrical unit according to an aspect of the present invention includes the cooling structure described above, the cooled portion that is an electrical component, and an electrical box that accommodates the cooled portion.

The electrical unit according to this aspect includes the cooling structure described above, the cooled portion that is an electrical component, and the electrical box that accommodates the cooled portion.

An electrical unit according to an aspect of the present invention includes a first temperature sensor that measures the temperature inside the electrical box, a second temperature sensor that measures the temperature of the heat transfer member, and a controller that calculates the dew point temperature in the electrical box based on information from the first temperature sensor and controls the heating state of the heater section based on the calculated dew point temperature and information from the second temperature sensor.

The electrical unit according to this aspect includes a first temperature sensor that measures the temperature inside the electrical box, a second temperature sensor that measures the temperature of the heat transfer member, and a controller that calculates the dew point temperature in the electrical box based on information from the first temperature sensor and controls the heating state of the heater section based on the calculated dew point temperature and information from the second temperature sensor. According to this, the heater section can be operated before dew condensation occurs on the heat transfer member.

Further, an outdoor unit according to one aspect of the present invention includes the electrical unit described above.

ADVANTAGE OF THE INVENTION According to the cooling structure of this invention, an electrical equipment unit provided with the same, and an outdoor unit, a heat-transfer member can be efficiently heated and the generation|occurrence|production of dew condensation can be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed an example of the refrigerating cycle by which the cooling structure which concerns on one Embodiment of this invention is employ|adopted. 1 is a front view of a cooling structure according to an embodiment of the invention; FIG. FIG. 3 is a cross-sectional view along the II cutting line shown in FIG. 2;

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cooling structure, an electrical unit including the cooling structure, and an outdoor unit according to an embodiment of the present invention will be described below with reference to the drawings.

The cooling structure 40 is a structure for cooling electrical components that control equipment such as the compressor 12 included in the refrigeration cycle 10 of the air conditioner.

As shown in FIG. 1, the refrigerating cycle 10 is configured by connecting devices such as a compressor 12, a condenser 14, an expansion valve 16, and an evaporator 18 by refrigerant piping. Also, the refrigerating cycle 10 is filled with refrigerant.

The compressor 12 compresses the low-pressure gas refrigerant led from the evaporator 18 and discharges high-temperature, high-pressure gas refrigerant.

The condenser 14 condenses the gas refrigerant discharged from the compressor 12 by heat exchange to form a high-pressure liquid refrigerant. The condenser 14 has a fan 15 and a heat exchanger (not shown), and heat is exchanged by the fan 15 and the heat exchanger.

The expansion valve 16 expands and evaporates the high-pressure liquid refrigerant led from the condenser 14 into a low-temperature, low-pressure gas-liquid mixed refrigerant.

The evaporator 18 evaporates the gas-liquid refrigerant introduced from the expansion valve 16 by heat exchange to obtain a low-pressure gas refrigerant. The evaporator 18 has a fan 19 and a heat exchanger (not shown), and heat is exchanged by the fan 19 and the heat exchanger.

Each of the devices described above and other devices constituting the air conditioner are controlled by electrical components housed in the electrical equipment box 30, and these electrical components are configured as an electric circuit for controlling the air conditioner.

The electrical components include, for example, a power element (part to be cooled) 32 (IPM: Intelligent Power Module) that controls the compressor 12 .

The power element 32 generates heat during operation (when energized). Therefore, it is necessary to cool the power element 32 in order to operate the power element 32 in an appropriate temperature environment, and the cooling structure 40 constitutes an electric circuit for controlling the air conditioner like the power element 32, and is a structure for cooling electrical components that generate heat during operation.

As shown in FIGS. 2 and 3 , the cooling structure 40 includes a heat transfer member 50 , a heater section 52 and refrigerant pipes (cooling section) 54 .

The heat transfer member 50 is a member for transferring cold heat from the refrigerant pipe 54 to the power element 32, and is a block-shaped member in which the heating region 50A and the cooling region 50B are integrally connected.
The heat transfer member 50 is made of a metal having excellent heat transfer properties, such as an aluminum alloy.

As shown in FIG. 3, the heating region 50A is one region (upper half region in the figure) of the heat transfer member 50 having a surface with which the heater portion 52 contacts, and is configured to have a predetermined plate thickness t1. On the other hand, the cooling region 50B is one region (lower half region in the figure) of the heat transfer member 50 having a surface in contact with the power element 32 and a surface in contact with the refrigerant pipe 54, and has a predetermined plate thickness t2. The term “thickness” as used herein refers to the dimension of the heat transfer member 50 in the left-right direction in FIG.

The plate thickness t1 is preferably set larger than the plate thickness t2. This makes the cross-sectional area of the heating region 50A larger than the cross-sectional area of the cooling region 50B. That is, the cross-sectional area is reduced in the vicinity of the boundary between the two areas from the heating area 50A to the cooling area 50B.

The back surface of the heating area 50A and the cooling area 50B that are integrally connected is a flat surface, and this flat back surface is arranged against the front surface of the electrical equipment box 30. As shown in FIG.

A heater section 52 is attached to the front surface of the heating area 50A (the surface opposite to the electrical equipment box 30).

A refrigerant pipe 54 is arranged in front of the cooling area 50B. Among electrical components, power elements 32 having heat-generating properties are mounted inside the electrical equipment box 30 adjacent to the cooling area 50B so as to be in thermal contact with the heat transfer member 50 . That is, the refrigerant pipe 54 and the power element 32 are arranged on respective surfaces of the heat transfer member 50 that face each other with the cooling region 50B interposed therebetween.

The heater unit 52 is a device whose main function is to generate heat, and the heat generation state is controlled by a heater control unit (control unit), which will be described later. When the heater portion 52 generates heat, the heat transfer member 50 (heating region 50A) is heated to raise the temperature.

It should be noted that the heater unit 52 is a component separate from the electrical component that constitutes the electric circuit that controls the air conditioner, and is configured so as not to affect the control function of the air conditioner.

The refrigerant pipe 54 is a refrigerant pipe through which a low-temperature refrigerant among refrigerants filled in the refrigerating cycle 10 flows. For example, as shown in FIG. Heat transfer member 50 (cooling area 50B) is cooled by refrigerant pipe 54 (low-temperature refrigerant), and power element 32 is further cooled by cooled heat transfer member 50 (cooling area 50B).

It should be noted that the extraction position and routing of the refrigerant pipe 54 are not limited to the form shown in FIG.
Further, not only the refrigerant pipe 54 (low-temperature refrigerant) but also a device or mechanism capable of cooling the power element 32 such as a water cooling device can be used as the cooling portion 54 .

As shown in FIG. 2, the shape of the refrigerant pipe 54 is changed in order to increase the contact area with the cooling region 50B.
Although not shown, a groove corresponding to the shape of the refrigerant pipe 54 may be formed in the heat transfer member 50 of the cooling region 50B. This can further increase the contact area.

As shown in FIGS. 2 and 3, a heat insulating material 56 covering the heating area 50A may be provided to prevent the heat of the heater section 52 from radiating to the outside (into the air) of the heating area 50A.

Although the heat insulating material 56 is not provided in the portion of the heating area 50A to which the heater section 52 is attached in the same drawing, the heat insulating material 56 may cover the heater section 52. FIG. That is, the heat insulating material 56 may cover the front, back, top, bottom, and both side surfaces of the heating area 50A.

As shown in FIG. 3 , a first temperature sensor 61 capable of measuring the internal temperature of the electrical box 30 is provided inside the electrical box 30 .

A second temperature sensor 62 capable of measuring the temperature of the heat transfer member 50 is also provided. At this time, the second temperature sensor 62 is preferably attached so as to measure the surface temperature of the cooling region 50B (for example, the heat transfer member 50 near the power element 32). This makes it possible to efficiently measure the temperature of the heat transfer member 50 in the vicinity of the power element 32 where the influence of dew condensation should be avoided.

The electrical components housed in the electrical box 30 include a heater control section that can acquire information from the first temperature sensor 61 and the second temperature sensor 62, and that performs necessary calculations and processing based on the acquired information.

The heater control section controls the heater section 52 as follows.
That is, the heater control unit acquires the temperature Tb inside the electrical box 30 from the first temperature sensor 61 .
Also, the heater control unit acquires the temperature Th of the heat transfer member 50 from the second temperature sensor 62 .

At the same time as obtaining information (temperature Tb) from the first temperature sensor 61, the heater control unit calculates the dew point temperature Td at the temperature Tb inside the electrical equipment box 30 at that time based on the information.
Further, the heater control unit compares the temperature Th of the heat transfer member 50 acquired from the second temperature sensor 62 with the calculated dew point temperature Td, and causes the heater unit 52 to generate heat when it determines that dew condensation occurs on the heat transfer member 50 .

Details of the comparison between the temperature Th of the heat transfer member 50 and the calculated dew point temperature Td are as follows, for example.
That is, it is determined that condensation occurs in the heat transfer member 50 when the temperature Th of the heat transfer member 50 drops to a temperature higher than the dew point temperature Td by a1°C with a margin of a1°C relative to the dew point temperature Td at which condensation occurs. That is, the heater control unit sets the threshold to Td+a1, and causes the heater unit 52 to generate heat when Th≦Td+a1. Note that a1° C. can be arbitrarily set according to the specifications of the air conditioner, and is set to a1=5° C., for example.

Heat generation of the heater portion 52 heats the heating region 50A of the heat transfer member 50 . Then, the heat of the heated heating region 50A is transmitted to the cooling region 50B. As a result, the temperature of the cooling region 50B rises and the occurrence of dew condensation is suppressed.

After that, when the temperature of the heat transfer member 50 rises to a predetermined temperature, the heater control section terminates the heat generation of the heater section 52 . The predetermined temperature referred to here is, for example, Td+a2 (a2>a1). At this time, by setting a2 to be larger than a1 (for example, a2=10° C.), it is possible to prevent a phenomenon in which the heater section 52 is frequently turned on and off in a short period of time (so-called Schmidt trigger).

The electrical box 30 (including electrical components, the first temperature sensor 61, the second temperature sensor 62, etc.) and the cooling structure 40 are housed in the outdoor unit of the air conditioner as an electrical unit.

According to this embodiment, the following effects are obtained.
The cooling structure 40 includes a heat transfer member 50 that constitutes an electric circuit that controls the air conditioner and is in thermal contact with the power element 32 that generates heat during operation, and a refrigerant pipe 54 that is in thermal contact with the heat transfer member 50 and cools the heat transfer member 50. According to this, the power element 32 can be cooled by the refrigerant pipe 54 (low-temperature refrigerant) via the heat transfer member 50 .

The cooling structure 40 also includes a heater portion 52 that heats the heat transfer member 50 by thermally contacting the heat transfer member 50 . According to this, the heater section 52 raises the temperature of the heat transfer member 50 before condensation occurs on the heat transfer member 50 due to excessive cooling by the refrigerant pipe 54 , thereby avoiding the occurrence of condensation.

At this time, the heater portion 52 is a component whose main function is to generate heat. Therefore, the temperature can be raised immediately. In addition, since the heater section 52 is a component that is functionally independent of the electric circuit that controls the air conditioner, it can be independently controlled without being affected by the control of the compressor 12 or the like. Therefore, control can be performed with good responsiveness, and control can be performed without being affected by the operating conditions of the air conditioner.

A heat insulating material 56 is provided so as to cover the heating area 50A. According to this, it is possible to prevent heat transferred from the heater section 52 to the heating region 50A from being radiated from the heating region 50A. Therefore, heat from the heater portion 52 can be efficiently stored in the heat transfer member 50 .

Moreover, the cross-sectional area of the heat transfer member 50 in the heating region 50A is made larger than the cross-sectional area of the heat transfer member 50 in the cooling region 50B. According to this, the heat from the heater section 52 is likely to be stored in the heat transfer member 50 in the heating region 50A where the heater section 52 is arranged. Moreover, since the heat accumulated in the heating region 50A moves intensively to the cooling region 50B having a smaller cross-sectional area than the heating region 50A, the heat from the heater section 52 can be efficiently transferred to the cooling region 50B.

A first temperature sensor 61 that measures the temperature Tb inside the electrical box 30, a second temperature sensor 62 that measures the temperature Th of the heat transfer member 50, and a heater control unit that calculates the dew point temperature Td based on information from the first temperature sensor 61 and controls the heating state of the heater unit 52 based on the calculated dew point temperature Td and the temperature Th of the heat transfer member 50. According to this, the heater section 52 can be operated before dew condensation occurs on the heat transfer member 50 .

10 Refrigeration cycle 12 Compressor 14 Condenser 15 Fan 16 Expansion valve 18 Evaporator 19 Fan 30 Electrical box 32 Power element (member to be cooled)
40 cooling structure 50 heat transfer member 50A heating region 50B cooling region 52 heater section 54 refrigerant pipe (cooling section)
56 heat insulating material 61 first temperature sensor 62 second temperature sensor

Claims (5)

a heat transfer member that constitutes an electric circuit that controls an air conditioner and is in thermal contact with a cooled portion that generates heat during operation;
a cooling unit that is in thermal contact with the heat transfer member to cool the heat transfer member;
a heater unit that is functionally independent of the electric circuit and is in thermal contact with the heat transfer member to heat the heat transfer member;
with
The heater section is arranged on the surface of the heating region of the heat transfer member,
The cooled portion and the cooled portion are arranged on respective surfaces facing each other across a cooling region of the heat transfer member different from the heating region ,
A cooling structure in which a cross-sectional area of the heat transfer member in the heating region when cut along a plane including a thickness direction of the heat transfer member is larger than the cross-sectional area of the heat transfer member in the cooling region. 2. The cooling structure according to claim 1, wherein the heat transfer member is provided with a heat insulating material covering the heating area. A cooling structure according to claim 1 or 2 ;
the cooled portion that is an electrical component;
an electrical box in which the cooled portion is accommodated;
Electrical unit with a first temperature sensor that measures the temperature inside the electrical box;
a second temperature sensor that measures the temperature of the heat transfer member;
a control unit that calculates the dew point temperature in the electrical box based on information from the first temperature sensor and controls the heating state of the heater unit based on the calculated dew point temperature and information from the second temperature sensor;
The electrical unit according to claim 3 , comprising: An outdoor unit comprising the electrical unit according to claim 3 or 4 .

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