JP2008223621A - Compressor and refrigeration cycle apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compressor unit and refrigeration cycle apparatus that reduces costs associated with insulation, and possesses high reliability. <P>SOLUTION: A electric motor 10 includes windings 3 wound on a split laminated iron core 1 via an insulation member 2, a stator formed by connecting a specified number of the laminated iron cores 1 annularly, a connection portion insulating member 6 for insulating connection portions when terminals 3a, 3b of the windings 3 wound around the laminated iron cores 1 are all connected to a three-phase power supply to form a delta-connection of a parallel circuit, a rotor 8 rotated by a rotating magnetic field generated by supplying power from the three-phase power supply. The motor 10 and a compression mechanism portion 12 for compressing the object to be compressed by a drive resulting from a rotation of the rotor 8 are accommodated in a sealed container 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric motor used for various industrial machines. In particular, it is suitable for a compressor used in a refrigeration cycle apparatus such as an air conditioner or a refrigeration apparatus.

  In recent years, various types of electric motors for the purpose of energy saving and environmental conservation have been required to be highly efficient and resource-saving (smaller and lighter). As a realization method, high density aligned winding is required. For this reason, concentrated winding (direct winding), in which windings are wound directly around an iron core, is progressing mainly in small electric motors. In some cases, the iron core may be divided for better alignment. (For example, refer to Patent Document 1).

Japanese Unexamined Patent Publication No. 9-23600 (page 3, FIG. 4)

  The electric motor described in Patent Document 1 is formed in a cylindrical shape by applying a predetermined number of laminated iron cores after arranging aligned windings on the laminated iron cores of the stator. After that, by connecting the ends of the windings, neutral points and input lines (U, V, W phase) are formed to form a stator of the motor. Here, in the configuration as described above, there are portions (hereinafter referred to as connection portions) where the windings are connected (connected) at four locations including at least the neutral point and the input line. Since all the connecting portions need to be insulated, if the number of connecting portions is increased, the processing cost for the insulating treatment and the cost of the insulating member are required. In particular, when applied to an electric motor inside a compressor such as a refrigerant, the motor may be immersed in the refrigerant (liquid) or lubricating oil. Therefore, problems such as leakage of electricity through the refrigerant and lubricating oil unless insulation treatment is strengthened. A point is considered.

  The present invention has been made to solve the above-described problems, and is intended to reduce the cost of insulation and obtain a highly reliable compressor and refrigeration cycle apparatus.

  In the compressor according to the present invention, a winding is wound around a divided laminated core via an insulating member, a stator formed by connecting a predetermined number of laminated cores in a ring shape, and each of the windings wound around each laminated core. An electric motor having a rotor that rotates by a rotating magnetic field generated by energization from an input power source, an insulating member for insulating a connection portion when a terminal is connected to an input power source, and a delta connection of a parallel circuit. A compression mechanism that is driven by the rotation of the child and compresses the object to be compressed is accommodated in an airtight container.

  In the compressor according to the present invention, in the electric motor, the windings wound around each laminated core are connected by the delta connection of the parallel circuit, and at this time, the connection portions corresponding to the U phase, the V phase, and the W phase are formed by the insulating member. Since only the insulation is required, the member cost and the processing cost for performing the attachment work can be reduced. Further, since the number of connected portions is reduced, the possibility of causing an insulation failure can be reduced. In particular, since the interior of the compressor is exposed to an atmosphere of lubricating oil, refrigerant, and the like, the number of connection portions can be reduced, so that the occurrence of failure and the like can be reduced, and a highly reliable compressor can be obtained at low cost.

Embodiment 1 FIG.
FIG. 1 is a schematic view of a longitudinal section of a compressor 20 according to Embodiment 1 of the present invention. As shown in FIG. 1, the sealed container 11 of the compressor 20 in the present embodiment accommodates at least the electric motor 10 and the compressor mechanism 12.

  FIG. 2 is a schematic view of the stator of the electric motor 10 according to Embodiment 1 as viewed from above. FIG. 2 also schematically shows a connection portion between the windings. In FIG. 2, a winding 3 is wound around a pole tooth via an insulating member 2 around a divided laminated core 1. Since the winding 3 can be wound directly on the pole teeth for each of the divided laminated iron cores 1, it is possible to relatively easily arrange high-density aligned windings without being disturbed by the adjacent pole teeth. This winding method is called so-called concentrated winding, and the winding 3 is directly wound around the pole teeth, so that the entire length of the winding 3 can be shortened and the amount of use of the winding 3 can be reduced. Further, the electrical resistance can be reduced by increasing the diameter of the winding, and the efficiency can be improved. Furthermore, it is possible to reduce the size and weight. Here, the winding 3 is actually wound around the laminated core 1 a plurality of times. However, in FIG. Terminals 3a and 3b of the winding 3 are terminals at the beginning and end of winding of the winding 3, respectively. In the present embodiment, the number of terminals is 18 (= 2 × 9).

  A predetermined number of the laminated cores 1 in this state are joined in a ring shape by a method such as welding to form an entire core of the stator. In the stator of the electric motor 10 of the present embodiment, nine laminated iron cores 1 are annularly joined and configured. However, it is not limited to this number. And in the connection part 4, the terminal 3a, 3b of the coil | winding 3 of each laminated iron core 1 is connected (connection). Each terminal 3a, 3b is divided into a U phase, a V phase, and a W phase and connected. One end portion of the lead wire 5 is also connected to the connection portion 4 that is a connection portion of each phase. A connector terminal 7 is connected to the other end of the lead portion 5. The connector terminal 7 is connected to a power input unit 13 outside the compressor 20 as will be described later. Thereby, each winding 3 connected in the connection part 4 and the three-phase alternating current power supply (input power supply, not shown) which is an external device are electrically connected via the power supply input part 13 and the connector terminal 7, Electrical input can be obtained (can be energized).

  FIG. 3 is an electric circuit diagram of the electric motor. The connection (connection) of the winding 3 is a delta connection in a parallel circuit as shown in FIG. 3, and there is no neutral point as in the star connection. For this reason, in the electric motor according to the present embodiment, only three connection portions 4 are required. In this embodiment, since the concentrated windings 3 are connected by delta connection, six terminals (three terminals 3a and 3b, respectively) are connected in each phase connection section 4.

  A connecting portion insulating member 6 is attached to each connecting portion 4 in order to obtain electrical insulation (hereinafter simply referred to as insulation). The connection part insulating member 6 is made of, for example, a cylindrical polyester film or the like, and insulates the connection part 4 by, for example, fusing the tube opening part. A voltage is applied to the winding 3 of the stator by supplying power from a three-phase power source, and current flows. However, insulation is necessary to prevent current leakage from the laminated iron core 1 and members around the motor and atmosphere. is there. In the electric motor 10 of the present embodiment, there are three connection portions 4, all of which are insulated by the connection portion insulating member 6. The rotor 8 rotates by receiving a force due to a rotating magnetic field generated in the stator by supplying power from a three-phase power source. As the rotor 8 rotates, the main shaft 9 also rotates. Here, as a form of the rotor 8, there is one corresponding to an induction motor, a brushless DC motor, or the like, but there is no particular limitation, and any form may be used.

A driving force is transmitted to the compressor mechanism 12 by the rotation of the main shaft 9 (rotor 8) of the electric motor 10. Thereby, it has a mechanism that can compress the captured compression object by changing (reducing) the volume. Examples of the mechanism type include a reciprocal type, a scroll type, and a rotary type, but the type is not particularly limited. Although not particularly limited, in the present embodiment, a refrigerant (particularly gas) used for refrigeration, an air conditioner, or the like is a compression target. As the refrigerant, for example, H410 refrigerants R410A, R404A, CO ₂ , ammonia, and the like are used.

  The power input unit 13 serves as an interface between the connector terminal 7 of the electric motor 10 in the sealed container 11 and a three-phase power source that is a device outside the compressor 20. The suction pipe 14 has a suction port and is provided for introducing the refrigerant compressed by the compressor mechanism 12 into the sealed container 11. On the other hand, the discharge pipe 15 has a discharge port, and is provided to send out the refrigerant compressed by the compressor mechanism 12 to the outside of the sealed container 11. The lubricating oil 16 is stored in the inside of the closed container 11 (particularly in the lower part) and is circulated by a pump or the like so as to maintain the lubrication and airtightness of the bearing of the compressor mechanism 12. The refrigerant compressor 20 is configured as described above, and the rotation of the main shaft 9 of the electric motor 10 can be used as power to perform refrigerant compression by the compressor mechanism unit 12.

  Next, the operation of the compressor 20 in the present embodiment will be described. In the electric motor 10 configured as described above, connections as shown in FIGS. 2 and 3 are made. A rotating magnetic field is generated inside the stator of the motor 10 that is supplied (energized) with the power from the three-phase power source connected to the connector terminal 7. A force due to a rotating magnetic field acts on the rotor 8 disposed on the inner diameter side of the stator, whereby the rotor 8 and the main shaft 9 rotate. When the main shaft 9 is rotated, for example, when the compressor 20 is of a scroll type, the swing scroll provided in the compressor mechanism unit 12 swings, and the volume of the refrigerant is changed between the fixed scroll and the compression. To do.

  As described above, in the electric motor 10 of the compressor 20 according to the first embodiment, the windings 3 wound around the laminated cores 1 are connected by delta connection, and the in-phase terminals 3a and 3b of the windings 3 are connected to each other. 4, the connection portion insulating members 6 are provided only at the three minimum connection portions 4 corresponding to the U-phase, V-phase, and W-phase, and insulation treatment is performed. The cost of the member required for the insulating member 6 and the processing cost for performing the attachment work can be reduced. Further, since the number of connection portions 4 to be insulated is reduced, the possibility of causing an insulation failure can be reduced. In particular, since the number of connection parts can be reduced inside the sealed container 11 exposed to the atmosphere of the lubricating oil 16 and the refrigerant, it is possible to reduce the occurrence of failure and the like and to obtain the highly reliable compressor 20 at a low cost. it can.

Embodiment 2. FIG.
FIG. 4 is a schematic view of the stator of the electric motor 10 according to Embodiment 2 as viewed from above. A connection portion of windings related to one phase is also schematically shown. In FIG. 4, those denoted by the same reference numerals as those in FIG. 1 play the same role as described in the first embodiment, and thus description thereof is omitted.

  In the above-described embodiment, six terminals having the same phase are connected at the connection portion 4 and connected to the connector terminal 7 via the lead wire 5. In the present embodiment, the terminal 3a, 3b of the winding 3 is directly connected to the connector terminal 7 using the connector terminal 7 of each phase as the connection portion 4. Here, also in the present embodiment, the connection method of the winding 3 is a delta connection in a parallel circuit as shown in FIG. 2, and there is no neutral point. Just do it.

  In the electric motor 10 configured as described above, connections as shown in FIGS. 2 and 3 are made. In the same manner as in the first embodiment, a rotating magnetic field is generated inside the stator in the motor 10 that is supplied with power from the three-phase power source connected to the connector terminal 7 (energized), and the rotor 8 And the main shaft 9 rotates. As the main shaft 9 rotates, the compressor mechanism 12 performs a refrigerant compression operation.

  As described above, according to the second embodiment, since each terminal 3a, 3b is directly connected to the connector terminal 7, there is no need to provide a connection portion other than the connector terminal 7, and no insulation failure occurs. It is not necessary to perform insulation treatment at that portion.

Embodiment 3 FIG.
In the above-described embodiment, the winding 3 is wound around the laminated core 1 by concentrated winding. Therefore, it is necessary to provide a connection part for connecting the terminals 3a and 3b as in the connection part 4 described in the first embodiment. In the present embodiment, the position where the connection portion in the sealed container 11 is provided will be examined.

  For example, when the compressor 20 is not performing a compression operation, liquid lubricating oil 16 is accumulated in the lower portion of the sealed container 11. Then, during the compression operation, the lubricating oil 16 is pumped up or wound up, and the rotating portion and the sliding portion are lubricated, and the excess lubricating oil 16 is also accumulated in the lower part. Further, not only the lubricating oil 16 but also a liquefied refrigerant or the like collects in the lower part. For example, a liquefied refrigerant or the like is more likely to conduct electricity than a vaporized state. Therefore, for example, when the connection part insulating member 6 has poor insulation, there is a risk of electric leakage to the sealed container 11 through the refrigerant or the lubricating oil. Further, it is desirable to provide a connection portion at a position where the influence of these liquids is not affected as much as possible even if the connection portion insulating member 6 is insulated.

  Therefore, in the electric motor 10 of the compressor 20, the connection portions (the connection portions 4 and the connector terminals 7) of the terminals 3 a and 3 b are above the main body of the electric motor 10 (on the main body or on the main body 10 or higher) when the sealed container 11 is accommodated in the compressor 20. The frequency at which the connecting portion is immersed in the lubricating oil 16 is lowered.

  Further, during the compression operation of the compressor 20, the refrigerant is sucked from the suction port of the suction pipe 14. At this time, for example, in addition to the refrigerant, foreign matter adhering to the device through which the refrigerant passes, refrigerant piping that circulates the refrigerant between these devices and the compressor 20, scales generated in the pipe connection are circulated in the refrigerant. Along with this, there is a possibility of entering the sealed container 11 together with the refrigerant. For example, if there is a gap between the pole teeth as in the case of concentrated winding, the foreign matter may enter between the pole teeth. Moreover, if it adheres or accumulates on a connection part, it will have a bad influence.

  Therefore, as shown in FIG. 1 and the like, a connecting portion is provided at a position where foreign matter or the like enters from the suction port of the suction pipe 14 and does not adhere. Here, for example, the terminals 3a and 3b are connected to the position of the suction port of the suction pipe 14 with the main shaft 9 as the center and at a substantially line-symmetrical position to provide a connection portion.

  As described above, in the compressor 20 of the present embodiment, the connecting portions (connecting portions 4 and connector terminals 7) for connecting the terminals 3a and 3b of the winding 3 are positioned at the upper side of the main body of the motor 10 or higher. Since it is provided, it is not immersed in a liquid such as the lubricating oil 16 accumulated in the lower part of the compressor 20. For this reason, it is possible to prevent a leakage of electric current to the sealed container 11 and to obtain a highly reliable compressor 20. In addition, maintenance management and the like can be performed efficiently.

Embodiment 4 FIG.
FIG. 5 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 4 of the present invention. In the present embodiment, an air conditioner will be described as an example of a refrigeration cycle apparatus. The air conditioner of FIG. 5 includes a heat source side unit (outdoor unit) 100 and a load side unit (indoor unit) 200, which are connected by a refrigerant pipe, and are a main refrigerant circuit (hereinafter referred to as a main refrigerant circuit). And the refrigerant is circulated. Among the refrigerant pipes, a pipe through which a gaseous refrigerant (gas refrigerant) flows is referred to as a gas pipe 300, and a pipe through which a liquid refrigerant (liquid refrigerant, which may be a gas-liquid two-phase refrigerant) flows is referred to as a liquid pipe 400.

  In the present embodiment, the heat source side unit 100 includes a compressor 101, an oil separator 102, a four-way valve 103, a heat source side heat exchanger 104, a heat source side fan 105, an accumulator (gas-liquid separator) 106, and a heat source side expansion device. (Expansion valve) 107, the inter-refrigerant heat exchanger 108, the bypass expansion device 109, and the heat source side control device 111.

  The compressor 101 uses the compressor 20 described in the first to third embodiments for the structure. On the other hand, for operation control, for example, an inverter circuit (not shown) is provided, and the operation frequency relating to the power supply of the three-phase power supply via the power input unit 13 is arbitrarily changed, whereby the rotor 8 and the spindle 9 are It is assumed that the rotation can be controlled and the capacity of the compressor 101 (amount of refrigerant sent out per unit time) can be finely changed accordingly.

  The oil separator 102 separates the lubricating oil 16 discharged from the compressor 101 mixed with the refrigerant. The separated lubricating oil 16 is returned to the compressor 101. The four-way valve 103 switches the refrigerant flow between the cooling operation and the heating operation based on an instruction from the heat source side control device 111. The heat source side heat exchanger 104 performs heat exchange between the refrigerant and air (outdoor air). For example, during the heating operation, it functions as an evaporator, performs heat exchange between the low-pressure refrigerant that has flowed in through the heat source side expansion device 107 and air, and evaporates and vaporizes the refrigerant. Further, during the cooling operation, it functions as a condenser and performs heat exchange between the refrigerant compressed in the compressor 101 flowing in from the four-way valve 103 side and air, thereby condensing and liquefying the refrigerant. The heat source side heat exchanger 104 is provided with a heat source side fan 105 in order to efficiently exchange heat between the refrigerant and the air. The heat source side fan 105 may also have an inverter circuit so that the operation frequency of the fan motor is arbitrarily changed to finely change the rotation speed of the fan.

  The inter-refrigerant heat exchanger 108 exchanges heat between the refrigerant flowing in the main flow path of the refrigerant circuit and the refrigerant branched from the flow path and adjusted in flow rate by the bypass expansion device 109 (expansion valve). . In particular, when it is necessary to supercool the refrigerant during the cooling operation, the refrigerant is supercooled and supplied to the load side unit 200. The liquid flowing through the bypass throttle device 109 is returned to the accumulator 106 via the bypass pipe 107. The accumulator 106 is means for storing, for example, liquid excess refrigerant. The heat source side control device 111 is composed of, for example, a microcomputer. It can be wired or wirelessly communicated with the load-side control device 204, for example, based on data relating to detection by various detection means (sensors) in the air conditioner, operation frequency control of the compressor 101 by inverter circuit control, etc. The respective units related to the air conditioner are controlled to control the operation of the entire air conditioner.

  On the other hand, the load side unit 200 includes a load side heat exchanger 201, a load side expansion device (expansion valve) 202, a load side fan 203, and a load side control device 204. The load side heat exchanger 201 performs heat exchange between the refrigerant and air. For example, it functions as a condenser during heating operation, performs heat exchange between the refrigerant flowing in from the gas pipe 300 and air, condenses and liquefies the refrigerant (or gas-liquid two-phase), and moves to the liquid pipe 400 side. Spill. On the other hand, during the cooling operation, it functions as an evaporator, performs heat exchange between the refrigerant and the air whose pressure is reduced by the load-side throttle device 202, causes the refrigerant to take heat of the air, evaporates it, and vaporizes it. It flows out to the piping 300 side. In addition, the load side unit 200 is provided with a load side fan 203 for adjusting the flow of air for heat exchange. The operating speed of the load-side fan 203 is determined by, for example, user settings. The load side expansion device 202 is provided to adjust the pressure of the refrigerant in the load side heat exchanger 201 by changing the opening degree.

  Further, the load side control device 204 is also composed of a microcomputer or the like, and can communicate with the heat source side control device 111 by wire or wireless, for example. Based on an instruction from the heat source side control device 111 and an instruction from a resident or the like, for example, each device (means) of the load side unit 200 is controlled so that the room has a predetermined temperature. Further, a signal including data related to detection by the detection means provided in the load side unit 200 is transmitted.

  Next, the operation of the air conditioner will be described. First, basic refrigerant circulation in the main refrigerant circuit during cooling operation will be described. The rotor 8 and the main shaft 9 of the electric motor 10 of the compressor 101 are rotated by the power supply from the three-phase power source. Thereby, the compressor mechanism part 12 compresses the refrigerant. The high-temperature, high-pressure gas (gas) refrigerant discharged from the discharge pipe 16 is condensed by passing through the heat source side heat exchanger 104 from the four-way valve 103 and flows out of the heat source side unit 100 as a liquid refrigerant. The refrigerant flowing into the load side unit 200 through the liquid pipe 400 evaporates as the low temperature and low pressure liquid refrigerant whose pressure is adjusted by adjusting the opening degree of the load side expansion device 202 passes through the load side heat exchanger 201. leak. Then, the gas flows into the heat source side unit 100 through the gas pipe 300, is sucked from the suction pipe 15 of the compressor 101 through the four-way valve 103 and the accumulator 106, and is circulated by being pressurized again and discharged.

  Further, basic refrigerant circulation in the main refrigerant circuit during heating operation will be described. The rotor 8 and the main shaft 9 of the electric motor 10 of the compressor 101 are rotated by the power supply from the three-phase power source. Thereby, the compressor mechanism part 12 compresses the refrigerant. The high-temperature, high-pressure gas (gas) refrigerant discharged from the discharge pipe 16 flows from the four-way valve 103 through the gas pipe 300 into the load side unit 200. In the load-side unit 200, the pressure is adjusted by adjusting the opening degree of the load-side expansion device 202, and condensed by passing through the load-side heat exchanger 201 to become an intermediate pressure liquid or a gas-liquid two-phase refrigerant. And flows out of the load side unit 200. The refrigerant flowing into the heat source side unit 100 through the liquid pipe 400 is pressure-adjusted by adjusting the opening degree of the heat source side expansion device 107, evaporates by passing through the heat source side heat exchanger 104, and becomes a gas refrigerant. Then, the refrigerant is sucked from the suction pipe 15 of the compressor 101 through the four-way valve 103 and the accumulator 106, and circulated by being pressurized and discharged as described above.

  As described above, in the fifth embodiment, the air conditioner that is a refrigeration cycle apparatus is configured using the compressor 101 having a small number of connecting portions of the winding 3 according to the above-described embodiment. Among them, the compressor 101, which is particularly important, has high reliability and can reduce the processing cost. Therefore, the air conditioner as a whole has high reliability and can reduce the cost.

Embodiment 5. FIG.
In the above-described fourth embodiment, the air conditioner has been described as the refrigeration cycle apparatus, but is not limited thereto. For example, the present invention can also be used for a cooling device, a heat pump device, and the like used for freezing and refrigerated warehouses.

It is a longitudinal cross-sectional view which shows the compressor 20 which concerns on Embodiment 1 of this invention. It is the schematic when the stator which concerns on Embodiment 1 is seen from the upper surface. It is an electric circuit diagram of the electric motor 10 of this invention. It is the schematic when the stator which concerns on Embodiment 1 is seen from the upper surface. 6 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 4. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Laminated iron core, 2 Insulation member, 3 Winding, 3a terminal (winding start), 3b terminal (winding end), 4 Connection part, 5 Lead wire, 6 Connection part insulation member, 7 Connector terminal, 8 Stator, 9 Spindle DESCRIPTION OF SYMBOLS 10 Electric motor, 11 Airtight container, 12 Compressor mechanism part, 13 Power supply input part, 14 Intake pipe, 15 Discharge pipe, 16 Lubricating oil, 100 Heat source side unit, 20, 101 Compressor, 102 Oil separator, 103 Four way valve 104 heat source side heat exchanger, 105 heat source side fan, 106 accumulator, 107 heat source side expansion device, 108 heat exchanger between refrigerants, 109 bypass expansion device, 110 heat source side control device, 200 load side unit, 201 load side heat exchanger 202 load side throttle device, 203 load side fan, 204 load side control device, 300 gas piping, 400 liquid piping.

Claims (5)

A winding is wound around the divided laminated core through an insulating member, a stator formed by annularly connecting a predetermined number of the laminated cores, and each terminal of the winding wound around each laminated core is used as an input power source. An insulating member for insulating a connecting portion when connected to form a delta connection of a parallel circuit, and an electric motor having a main shaft that rotates with a rotor by a rotating magnetic field generated by energization from the input power source,
A compressor characterized in that a compression mechanism that is driven by the rotation of the main shaft to compress the object to be compressed is housed in a sealed container. A winding is wound around the divided laminated core through an insulating member, a stator formed by annularly connecting a predetermined number of the laminated cores, and each terminal of the winding wound around each laminated core is used as an input power source. When connected to form a delta connection in a parallel circuit, each terminal is directly connected, a connector terminal for connecting each terminal to the input power supply, and a rotor by a rotating magnetic field generated by energization from the input power supply An electric motor having a spindle that rotates with
A compressor characterized in that a compression mechanism that is driven by the rotation of the main shaft to compress the object to be compressed is housed in a sealed container.   3. The compressor according to claim 1, wherein each end of the winding is connected at a position above the position where the electric motor is housed in a container.   Each of the windings is positioned above the position where the electric motor is housed and is substantially line symmetric about the main axis with respect to the position of the suction port provided in the container for taking in the object to be compressed. 3. The compressor according to claim 1, wherein a terminal is connected. A compressor according to any one of claims 1 to 4, which compresses a refrigerant;
A condenser that condenses the refrigerant by heat exchange;
A throttle device for reducing the pressure of the condensed refrigerant;
A refrigeration cycle device comprising a refrigerant circuit configured by pipe-connecting an evaporator for evaporating the refrigerant by exchanging heat between the decompressed refrigerant and air.

Images