WO2022215242A1

WO2022215242A1 - Outdoor unit and air-conditioning device

Info

Publication number: WO2022215242A1
Application number: PCT/JP2021/014989
Authority: WO
Inventors: 哲二七種; 洋次尾中
Original assignee: 三菱電機株式会社
Priority date: 2021-04-09
Filing date: 2021-04-09
Publication date: 2022-10-13

Abstract

This outdoor unit, which connects to a load-side heat exchanger and a throttle device with piping to configure a refrigerant circuit, is provided with a compressor, a refrigerant flow path switching device which switches the flow path, an outdoor-side heat exchanger which exchanges heat between an external fluid and the internally circulating refrigerant, and an auxiliary heat exchanger which, in cooling operation, supercools refrigerant flowing out of the outdoor-side heat exchanger, wherein the outdoor-side heat exchanger comprises a pair of headers which are arranged separated from each other in the vertical direction and through which the refrigerant passes, multiple flat heat transfer tubes which are arranged between the pair of headers and apart from each other, with the flat surfaces on the long side of the flat shapes facing each other, and multiple corrugated fins which are arranged between the mutually adjacent flat heat transfer tubes; the flat heat transfer tubes are arranged in multiple rows along the direction of flow of the external fluid, one of the pair of headers is a fold-back header which bridges the refrigerant from one row of the flat heat transfer tubes back to the other row of flat heat transfer tubes, and the refrigerant is bridged back by means of the return header one time.

Description

Outdoor unit and air conditioner

This technology relates to outdoor units and air conditioners. In particular, it relates to heat exchangers with headers and the like.

In recent years, in order to reduce the amount of refrigerant and improve the performance of heat exchangers, heat exchanger tubes for air conditioners have been made thinner. As heat transfer tubes become narrower, the number of branches in heat exchangers increases in order to suppress an increase in refrigerant pressure loss. In order to cope with such multi-branch distribution, a heat exchanger using a header-type refrigerant distributor having headers on top and bottom in the height direction has been developed (see, for example, Patent Document 1).

JP 2014-194339 A

Here, in the air conditioner, the refrigerant flow in the refrigerant circuit differs depending on the operation mode. Therefore, a heat exchanger used in an air conditioner has both functions of a condenser and an evaporator. Here, in a heat exchanger in which a partition plate or the like is provided in the header and the refrigerant is folded back multiple times between the headers to pass through the inside of the heat exchanger, the flow path of the refrigerant becomes long in the heat exchanger. As the flow path of the refrigerant becomes longer, the pressure loss of the refrigerant increases in the heat exchanger functioning as an evaporator. When the pressure loss of the refrigerant increases, the suction pressure on the suction side of the compressor decreases, so the efficiency of the entire refrigeration cycle apparatus deteriorates.

On the other hand, if the heat exchanger has a passage length that allows for the pressure loss of the refrigerant flowing inside the heat exchanger without providing a partition plate or the like in the header, the refrigerant flowing through the heat transfer tube when functioning as a condenser flow velocity decreases, and the differential pressure of the refrigerant between the inlet and outlet of the heat transfer tubes becomes smaller. When the differential pressure of the refrigerant between the inlet and outlet of the heat transfer tubes becomes smaller than the liquid head of the condensed liquid refrigerant (liquid refrigerant) in the heat transfer tubes, the liquid refrigerant may accumulate in a part of the heat exchanger. . Therefore, when the heat exchanger functions as a condenser, the heat exchange performance is lowered, and the efficiency of the refrigeration cycle device is deteriorated.

Therefore, it is desirable to solve the above problems and provide an outdoor unit and an air conditioner having an outdoor heat exchanger capable of maintaining high heat exchange performance even when both evaporating and condensing refrigerant. aim.

The outdoor unit according to this disclosure is an outdoor unit that is connected to a load-side heat exchanger and an expansion device to form a refrigerant circuit, and includes a compressor that compresses and discharges the sucked refrigerant, a cooling operation and a heating operation. and an outdoor heat exchanger that exchanges heat between the refrigerant passing through the inside and the external fluid, and the refrigerant flowing out from the outdoor heat exchanger in cooling operation. and an auxiliary heat exchanger for supercooling the refrigerant flowing through the main refrigerant circuit, the outdoor heat exchanger being arranged vertically apart from each other, a pair of headers through which the refrigerant passes through the pipes, and a flat cross section. and a plurality of flat heat transfer tubes arranged between a pair of headers with the flat surfaces on the longitudinal sides of the flat shapes opposed to each other with a gap therebetween, and having a flow path in which a refrigerant flows, and two adjacent heat transfer tubes It has a plurality of corrugated fins arranged between the flat heat transfer tubes and joined to the flat heat transfer tubes on the flat surface, the flat heat transfer tubes are arranged in a plurality of rows along the flow direction of the external fluid, and the pair of headers One of them is a folded header that bridges the refrigerant from one row of flat heat transfer tubes to another row of flat heat transfer tubes, and the number of times that the refrigerant is bridged by the folded header is one.

In addition, an air conditioner according to this disclosure includes the outdoor unit described above, and an indoor unit that has a load-side heat exchanger and an expansion device and conditions air in an air-conditioned space.

According to this disclosure, the outdoor unit includes an outdoor heat exchanger in which a pair of headers, one of which is a folded header, is arranged in the vertical direction, and an auxiliary heat exchanger that supercools the refrigerant flowing out of the outdoor heat exchanger. have a vessel By setting the number of turns in the turn-back header to one, the flow path of the refrigerant in the outdoor heat exchanger is shortened, and the pressure loss of the refrigerant can be suppressed. The auxiliary heat exchanger eliminates the need to supercool the refrigerant in the outdoor heat exchanger, thereby preventing the refrigerant from stagnation in the outdoor heat exchanger. Therefore, high heat exchange performance can be maintained in both cases where the outdoor heat exchanger functions as an evaporator and a condenser.

1 is a diagram showing the configuration of an air conditioner according to Embodiment 1. FIG. 1 is a diagram illustrating a configuration of a heat exchanger 10 according to Embodiment 1; FIG. FIG. 4 is a diagram for explaining the relationship between the refrigerant pressure loss and COP in the heat exchanger according to Embodiment 1, and the number of turns; FIG. 4 is a diagram for explaining a staying state of liquid refrigerant in a heat exchanger; FIG. 4 is a diagram showing the relationship between the differential pressure between the refrigerant inlet/outlet pipe 12 on the refrigerant inflow side and the refrigerant inlet/outlet pipe 12 on the refrigerant outflow side and the rate at which the liquid refrigerant stays. FIG. 4 is a diagram showing the relationship between the degree of subcooling of liquid refrigerant and the condensation performance of a heat exchanger; 2 is a Ph diagram in the air conditioner according to Embodiment 1. FIG. It is a figure which shows the relationship between a supercooling degree and COP. FIG. 4 is a diagram showing the configuration of an air conditioner according to Embodiment 2; 2 is a Ph diagram of the air conditioner in Embodiment 2. FIG. FIG. 10 is a diagram showing the configuration of an air conditioner according to Embodiment 3; FIG. 11 is a diagram illustrating the flow of opening/closing control of a two-way valve 290 performed by a control device 400 according to Embodiment 3; FIG. 13 is a diagram illustrating the flow of opening degree control of a diaphragm device 120 performed by a control device 400 according to Embodiment 4; FIG. 12 is a diagram illustrating the flow of opening degree control of a refrigerant amount adjustment valve 250 performed by a control device 400 according to Embodiment 5; FIG. 12 is a diagram illustrating the flow of control of the degree of opening of a refrigerant amount adjustment valve 250 performed by a control device 400 according to Embodiment 6; FIG. 21 is a diagram for explaining the flow of control of the degree of opening of a refrigerant amount adjustment valve 250 performed by a control device 400 according to Embodiment 7; FIG. 21 is a diagram for explaining the flow of opening degree control of a refrigerant amount adjustment valve 250 performed by a control device 400 according to Embodiment 8;

Below, the outdoor unit and the air conditioner according to the embodiment will be described with reference to the drawings. In the following drawings, the same reference numerals denote the same or corresponding parts, and are common throughout the embodiments described below. Also, in the drawings, the size relationship of each component may differ from the actual size. The forms of the constituent elements shown in the entire specification are merely examples, and are not limited to the forms described in the specification. In particular, the combination of components is not limited to only the combinations in each embodiment, and components described in other embodiments can be applied to other embodiments. Also, the upper side in the drawing is referred to as "upper" and the lower side as "lower". Further, the levels of pressure and temperature are not determined in relation to absolute values, but relatively determined by the state, operation, etc. of the apparatus. In addition, when there is no need to distinguish or specify a plurality of devices of the same type that are distinguished by subscripts, the subscripts may be omitted.

Embodiment 1.
<Configuration of air conditioner>
FIG. 1 is a diagram showing the configuration of an air conditioner according to Embodiment 1. FIG. Here, an air conditioner will be described as an example of a refrigeration cycle device. As shown in FIG. 1 , the air conditioner of Embodiment 1 has an outdoor unit 200 , an indoor unit 100 and two refrigerant pipes 300 . The compressor 210, the four-way valve 220, and the outdoor heat exchanger 230 of the outdoor unit 200 and the indoor heat exchanger 110 and the expansion device 120 of the indoor unit 100 are connected by refrigerant pipes 300 to form a refrigerant circuit. Configure. Here, in the air conditioner of Embodiment 1, one outdoor unit 200 and one indoor unit 100 are connected by pipes. However, the number of connected devices is not limited to this.

The indoor unit 100 has an indoor fan 130 in addition to the indoor heat exchanger 110 and the expansion device 120 . The expansion device 120 is a device having an expansion valve or the like for decompressing and expanding the refrigerant. For example, when the throttle device 120 is configured by an electronic expansion valve or the like, the degree of opening is adjusted based on an instruction from a control device 400 or the like, which will be described later. The indoor-side heat exchanger 110 is a load-side heat exchanger that exchanges heat between the indoor air, which is the space to be air-conditioned, and the refrigerant. For example, during heating operation, indoor heat exchanger 110 functions as a condenser to condense and liquefy refrigerant. During cooling operation, indoor heat exchanger 110 functions as an evaporator to evaporate and vaporize the refrigerant. The indoor fan 130 passes the indoor air through the indoor heat exchanger 110 and supplies the air that has passed through the indoor heat exchanger 110 to the room. Here, the indoor-side heat exchanger 110 is described as one that directly exchanges heat between the refrigerant and the indoor air, but is not limited to this. Indoor heat exchanger 110 may, for example, exchange heat between the refrigerant and water through water, and the water may exchange heat with indoor air.

The outdoor unit 200 is equipment installed outside the air-conditioned space. Here, the outdoor unit 200 of Embodiment 1 will be described as being of the top-flow type. The outdoor unit 200 of Embodiment 1 includes a compressor 210, a four-way valve 220, an outdoor heat exchanger 230, an auxiliary heat exchanger 240, a refrigerant amount adjustment valve 250, a bypass pipe 260, and an accumulator as devices constituting a refrigerant circuit. 270. The outdoor unit 200 also has an outdoor fan 280 . Compressor 210 compresses and discharges the sucked refrigerant. Compressor 210 is, for example, a scroll compressor, a reciprocating compressor, or a vane compressor. Here, the air conditioner of Embodiment 1 has inverter device 215 or the like, for example, and can arbitrarily change the driving frequency of electric power supplied to compressor 210 . By changing the drive frequency, the motor (not shown) of compressor 210 can change the number of revolutions and the drive capacity of compressor 210 can be changed. However, it is not limited to this. Compressor 210 may also have inverter device 215 .

The four-way valve 220, which serves as a refrigerant flow switching device, is a valve that switches the refrigerant flow depending on, for example, cooling operation and heating operation. Four-way valve 220 connects the discharge side of compressor 210 and indoor heat exchanger 110 and also connects the suction side of compressor 210 and outdoor heat exchanger 230 when heating operation is performed. Further, the four-way valve 220 connects the discharge side of the compressor 210 to the outdoor heat exchanger 230 and connects the suction side of the compressor 210 to the indoor heat exchanger 110 during cooling operation. Here, the case of using the four-way valve 220 is illustrated, but the channel switching device is not limited to this. For example, a flow path switching device may be formed by combining a plurality of two-way valves.

The outdoor heat exchanger 230 exchanges heat between the refrigerant and the outdoor air. Here, outdoor heat exchanger 230 of Embodiment 1 functions as an evaporator during heating operation, and evaporates and vaporizes the refrigerant. On the other hand, during cooling operation, outdoor heat exchanger 230 functions as a condenser to condense and liquefy the refrigerant. Also, as shown in FIG. 1, the outdoor heat exchanger 230 here has two

heat exchangers

10A and 10B. In the refrigerant circuit, it is assumed that the heat exchanger 10A and the heat exchanger 10B are pipe-connected so as to be parallel to each other. Details of the heat exchanger 10 (heat exchanger 10A and heat exchanger 10B) will be described later. Here, the outdoor heat exchanger 230 is described as exchanging heat between the refrigerant and the outdoor air, but it may exchange heat between the refrigerant and another external fluid. In addition, the outdoor blower 280 is driven to pass air from the outside of the outdoor unit 200 through the outdoor heat exchanger 230 to form an air flow that flows out from the inside of the outdoor unit 200 .

The auxiliary heat exchanger 240 has, for example, a double tube or plate heat exchanger. Auxiliary heat exchanger 240 subcools the refrigerant flowing out of outdoor heat exchanger 230 during cooling operation. Auxiliary heat exchanger 240 exchanges heat between the refrigerant that flows out of outdoor heat exchanger 230 and flows through the main refrigerant circuit toward indoor heat exchanger 110 and the refrigerant that has passed through bypass pipe 260 and refrigerant amount adjustment valve 250. It is a heat exchanger between refrigerants. A bypass pipe 260 is a pipe that forms a bypass flow path. In the bypass flow path, part of the refrigerant that has passed through the main refrigerant circuit side of the auxiliary heat exchanger 240 branches during cooling operation, passes through the refrigerant amount adjustment valve 250 and the bypass flow path side of the auxiliary heat exchanger 240, This is the flow path through which the coolant flows into the accumulator 270 . Refrigerant amount adjustment valve 250 is a refrigerant amount adjustment device that is arranged in bypass pipe 260 and adjusts the amount of refrigerant that passes through bypass pipe 260 . At this time, the refrigerant amount adjustment valve 250 reduces the pressure of a part of the refrigerant that has passed through the auxiliary heat exchanger 240 and branches, and allows the refrigerant to pass through the bypass flow path side of the auxiliary heat exchanger 240 .

The accumulator 270 is installed on the suction side of the compressor 210 . The accumulator 270 passes gaseous refrigerant (hereinafter referred to as gas refrigerant) and accumulates liquid refrigerant (hereinafter referred to as liquid refrigerant).

The control device 400 controls the equipment of the air conditioner. Control device 400 controls, for example, expansion device 120, compressor 210, refrigerant amount adjustment valve 250, and the like. The control device 400 can be configured with hardware such as a circuit device that implements its functions. Moreover, it can be composed of an arithmetic unit having a microcomputer, a CPU, and the like, and software. Control is realized by the arithmetic unit executing software.

The air conditioner also has a detection unit 500. The detection unit 500 of Embodiment 1 has a discharge side pressure sensor 510 , a suction side pressure sensor 511 , an inter-heat exchanger temperature sensor 520 , an auxiliary heat exchanger temperature sensor 521 and a bypass pipe temperature sensor 522 . Discharge-side pressure sensor 510 is a detection device that detects the pressure of the refrigerant on the discharge side of compressor 210 . Also, the suction side pressure sensor 511 is a detection device that detects the pressure of the refrigerant on the suction side of the compressor 210 . Inter-heat exchanger temperature sensor 520 is a detection device that detects the temperature of the refrigerant between outdoor heat exchanger 230 and auxiliary heat exchanger 240 . Therefore, inter-heat-exchanger temperature sensor 520 detects the temperature of the refrigerant flowing out of outdoor heat exchanger 230 during cooling operation. Auxiliary heat exchanger temperature sensor 521 detects the temperature of the refrigerant that has passed through auxiliary heat exchanger 240 . Here, the auxiliary heat exchanger temperature sensor 521 detects the temperature of supercooled refrigerant flowing out of the auxiliary heat exchanger 240 during cooling operation. Bypass pipe temperature sensor 522 is a detection device that detects the temperature of the refrigerant passing through bypass pipe 260 . Here, the bypass pipe temperature sensor 522 detects the temperature of the refrigerant after passing through the refrigerant amount adjustment valve 250 and the bypass passage side of the auxiliary heat exchanger 240 .

<Configuration of heat exchanger 10>
FIG. 2 is a diagram illustrating the configuration of the heat exchanger 10 according to Embodiment 1. FIG. The outdoor heat exchanger 230 has a corrugated fin tube type heat exchanger 10 of parallel pipe type. As described above, the outdoor heat exchanger 230 of the outdoor unit 200 has two heat exchangers 10 (heat exchanger 10A and heat exchanger 10B). The heat exchanger 10A and the heat exchanger 10B are pipe-connected in parallel in the refrigerant circuit. However, the number and form of connections in the refrigerant circuit of Embodiment 1 are not limited to this.

Each heat exchanger 10 has two distribution headers 11 (distribution header 11A and distribution header 11B), a folded header 13, a plurality of flat heat transfer tubes 14 and a plurality of corrugated fins 15.

In the heat exchanger 10 of the outdoor heat exchanger 230 according to Embodiment 1, a pair of headers consisting of two distribution headers 11 and a folded header 13 are arranged separately vertically in the height direction. Here, the distance between the pair of headers is 800 mm or more. In the outdoor unit 200, since devices such as the compressor 210 are installed below the outdoor unit 200, the return header 13 is positioned above due to piping connections and the like, and the two distribution headers 11 It is arranged below the folded header 13 .

Between the two distribution headers 11 and the return headers 13, a plurality of flat heat transfer tubes 14 are arranged so that their flat surfaces face each other so as to be perpendicular to the distribution headers 11 and the return headers 13 and parallel to each other. are arranged in two rows. A group of flat heat transfer tubes 14 in one row is connected to one distribution header 11 . As described above, since the distance between the pair of headers is 800 mm or more, the length of the flat heat transfer tubes 14 in the heat exchanger 10 of the outdoor heat exchanger 230 in Embodiment 1 is 800 mm or more.

The distribution headers 11 are pipes that are pipe-connected to other devices that constitute the refrigeration cycle device, flow in and out of the refrigerant, which is a fluid that serves as a heat exchange medium, and branch or join the refrigerant. The distribution headers 11 each have refrigerant inlet/outlet pipes 12 (refrigerant inlet/outlet pipe 12A and refrigerant inlet/outlet pipe 12B) through which refrigerant flows in and out from the outside. Moreover, the turn-back header 13 is a header that serves as a bridge that turns back a group of flat heat transfer tubes 14 in one row to a group of flat heat transfer tubes 14 in the other row.

The flat heat transfer tube 14 has a flat shape in cross section, and has a planar outer surface on the longitudinal side of the flat shape along the depth direction, which is the direction of air flow. The heat transfer tube has curved side surfaces. The flat heat transfer tube 14 of Embodiment 1 is a multi-hole flat heat transfer tube having a plurality of holes serving as refrigerant flow paths inside the tube. In Embodiment 1, the holes of the flat heat transfer tubes 14 are formed to face the height direction so as to form flow paths between the distribution headers 11 and the folded headers 13 . As described above, the flat heat transfer tubes 14 are arranged at equal intervals in the horizontal direction so that the outer surfaces on the longitudinal sides face each other. When manufacturing the heat exchanger 10 of the outdoor heat exchanger 230 in Embodiment 1, each flat heat transfer tube 14 is inserted into an insertion hole (not shown) of the distribution header 11 and the folded header 13, Brazed and joined. As a brazing material for brazing, for example, a brazing material containing aluminum is used. Thereby, the distribution header 11, the folded header 13, and the inside of each flat heat transfer tube 14 communicate with each other.

Corrugated fins 15 are arranged between the flat surfaces of the arranged flat heat transfer tubes 14 facing each other. The corrugated fins 15 are arranged to expand the heat transfer area between the refrigerant and the outside air. The corrugated fins 15 are corrugated on a plate material, and are bent into a wavy bellows shape by repeating mountain folds and valley folds. Here, the bent portion due to the unevenness formed in the wavy shape becomes the apex of the wavy shape. In Embodiment 1, the tops of the corrugated fins 15 are aligned in the height direction. The corrugated fins 15 are in surface contact with the flat surfaces of the flat heat transfer tubes 14 and the corrugated tops. Then, the contact portion is brazed and joined with a brazing material. The plate material of the corrugated fins 15 is made of, for example, an aluminum alloy. Then, the surface of the plate material is clad with a brazing material layer. The clad braze layer is based on, for example, an aluminum-containing braze material of the aluminum-silicon system.

<Operation of air conditioner>
Next, the operation of each device of the air conditioner will be described based on the flow of refrigerant. First, the operation of each device in the refrigerant circuit in heating operation will be described based on the flow of the refrigerant. During heating operation, control device 400 closes refrigerant amount adjustment valve 250 . Solid line arrows in FIG. 1 indicate the flow of the refrigerant in the heating operation. The high-temperature and high-pressure gas refrigerant compressed by compressor 210 and discharged passes through four-way valve 220 and flows into indoor heat exchanger 110 . The gas refrigerant condenses and liquefies by exchanging heat with the air in the air-conditioned space while passing through the indoor heat exchanger 110 . The condensed and liquefied refrigerant passes through the throttle device 120 . The refrigerant is depressurized as it passes through the expansion device 120 . The refrigerant depressurized by the expansion device 120 and brought into a gas-liquid two-phase state passes through the auxiliary heat exchanger 240 and the outdoor heat exchanger 230 . Here, since the refrigerant amount adjustment valve 250 is closed, heat exchange between refrigerants is not performed in the auxiliary heat exchanger 240 . In the outdoor heat exchanger 230, the refrigerant evaporated and gasified by exchanging heat with the outdoor air sent from the outdoor blower 280 passes through the four-way valve 220 and the accumulator 270, and is returned to the compressor 210. inhaled. As described above, the refrigerant in the air conditioner circulates to perform air conditioning for heating.

Next, I will explain the cooling operation. During cooling operation, control device 400 adjusts refrigerant amount adjustment valve 250 to allow a portion of the refrigerant passing through the main refrigerant circuit to pass through bypass pipe 260 . Dotted arrows in FIG. 1 indicate the flow of the refrigerant in the cooling operation. The high-temperature and high-pressure gas refrigerant compressed by compressor 210 and discharged passes through four-way valve 220 and flows into outdoor heat exchanger 230 . Then, the refrigerant passes through the outdoor heat exchanger 230 and exchanges heat with the outdoor air supplied by the outdoor fan 280 to be condensed and liquefied. A part of the refrigerant that has passed through the main refrigerant circuit side of the auxiliary heat exchanger 240 passes through the bypass pipe 260, is decompressed in the refrigerant amount adjustment valve 250, becomes a low-temperature and low-pressure refrigerant, and bypasses the auxiliary heat exchanger 240. Pass through the piping side. Therefore, heat is exchanged between the refrigerants, and the refrigerant passing through the main refrigerant circuit side of the auxiliary heat exchanger 240 is subcooled. The liquefied refrigerant passes through the throttle device 120 . Here, when the refrigerant passes through the expansion device 120, it is decompressed and becomes a gas-liquid two-phase state. The refrigerant depressurized by the expansion device 120 and in a gas-liquid two-phase state passes through the indoor heat exchanger 110 . Then, in the indoor heat exchanger 110, for example, the refrigerant evaporated and gasified by exchanging heat with the air in the air-conditioned space passes through the four-way valve 220 and is sucked into the compressor 210 again. As described above, the refrigerant in the air conditioner circulates to perform air conditioning for cooling.

FIG. 3 is a diagram for explaining the relationship between the refrigerant pressure loss and COP in the heat exchanger according to Embodiment 1 and the number of turns. Here, the number of turns is the number of times the refrigerant passing through the heat exchanger 1 of the outdoor heat exchanger 230 is turned back at the distribution header 11 . For example, if the inside of the distribution header 11 and the return header 13 are partitioned by a partition plate or the like to divide the inside of the heat exchanger 1 into a plurality of blocks, the refrigerant can be bridged between the blocks inside the header. For this reason, the heat exchanger 1 has a turn configuration in which the refrigerant is folded back several times and flows back and forth in the vertical direction.

The outdoor heat exchanger 230 functions as an evaporator when the air conditioner performs heating operation. As shown in FIG. 3, when the number of turns increases, the refrigerant pressure loss increases and the COP in heating operation (hereinafter referred to as heating COP) decreases. When the inside of the distribution header 11 is not partitioned and the number of turns is 0, the heating COP is the highest. Therefore, in the heat exchanger 1, the outdoor heat exchanger 230 of Embodiment 1 has a configuration in which the inside of the header is not partitioned.

FIG. 4 is a diagram for explaining the stagnation state of the liquid refrigerant in the heat exchanger. When the air conditioner performs cooling operation, the outdoor heat exchanger 230 serves as a condenser. When the inside of the distribution header 11 of the outdoor heat exchanger 230 is not partitioned and the number of turns is set to 0, the surface temperature is measured by thermography. Stagnation occurs.

FIG. 5 is a diagram showing the relationship between the differential pressure between the refrigerant inlet/outlet pipe 12 on the refrigerant inflow side and the refrigerant inlet/outlet pipe 12 on the refrigerant outflow side and the rate at which the liquid refrigerant stays. When the inside of the distribution header 11 of the outdoor heat exchanger 230 is not partitioned and the number of turns is set to 0, the flow velocity of the refrigerant flowing through the flat heat transfer tubes 14 slows down, and the differential pressure of the refrigerant inlet/outlet pipes 12 decreases. Therefore, as shown in FIG. 5, the differential pressure between the refrigerant inlet/outlet pipes 12 is smaller than the liquid head of the liquid refrigerant condensed in the flat heat transfer tubes 14, and the liquid refrigerant stays at a higher rate. .

FIG. 6 is a diagram showing the relationship between the degree of supercooling of the liquid refrigerant and the condensation performance of the heat exchanger. As shown in FIG. 6, when the degree of subcooling of the liquid refrigerant is increased, the rate at which the liquid refrigerant stays increases. Therefore, if the degree of supercooling of the refrigerant passing through the heat exchanger is increased, the condensation performance becomes worse than the condensation performance predicted under the condition where no liquid refrigerant is retained. Therefore, as shown in FIG. 6, if the degree of subcooling of the refrigerant passing through the heat exchanger is reduced, the effect of the liquid refrigerant stagnation is reduced, and condensing performance close to prediction can be ensured. .

FIG. 7 is a Ph diagram in the air conditioner according to Embodiment 1. FIG. As shown in FIG. 7, when the degree of supercooling (SC) of the refrigerant is small, the refrigerating effect becomes small. For this reason, the cooling capacity that can be calculated by multiplying the cooling effect by the refrigerant circulation amount is reduced, and the air conditioner becomes insufficient in capacity.

FIG. 8 is a diagram showing the relationship between the degree of supercooling and the COP. If the degree of subcooling of the refrigerant is reduced so that the liquid refrigerant does not stagnate, the COP in the cooling operation (hereinafter referred to as cooling COP) deviates from the peak point at which it reaches its maximum. Therefore, in the air conditioner of Embodiment 1, when the cooling operation is performed, the degree of supercooling of the liquid refrigerant passing through the outdoor heat exchanger 230 is reduced, and the auxiliary heat exchanger 240 supercools the refrigerant. Ensure degree.

As described above, according to the air conditioner of Embodiment 1, the outdoor heat exchanger 230 has the distribution header 11 and the folded header 13 in the vertical direction, and the refrigerant is folded back to form a plurality of columns. It allows the flat heat transfer tubes 14 to pass through. It also has an auxiliary heat exchanger 240 that supercools the refrigerant flowing out of the outdoor heat exchanger 230 when the outdoor heat exchanger 230 functions as a condenser. Therefore, the degree of supercooling of the refrigerant with a small degree of supercooling flows out from the outdoor heat exchanger 230 , and the degree of supercooling can be added to the refrigerant in the auxiliary heat exchanger 240 . Therefore, it is possible to prevent the liquid refrigerant from staying in the outdoor heat exchanger 230 . On the other hand, during heating operation in which outdoor heat exchanger 230 functions as an evaporator, the number of turns in outdoor heat exchanger 230 is zero. Therefore, it is possible to suppress an increase in the pressure loss of the refrigerant.

Embodiment 2.
9 is a diagram showing a configuration of an air conditioner according to Embodiment 2. FIG. In FIG. 9, devices and the like denoted by the same reference numerals as in FIG. 1 perform the same functions and operations as those described in the first embodiment. As shown in FIG. 9 , the air conditioner of Embodiment 2 has a liquid receiver 285 . The liquid receiver 285 stores liquid refrigerant. The liquid receiver 285 is installed between the outdoor heat exchanger 230 and the auxiliary heat exchanger 240 in the main refrigerant circuit.

FIG. 10 is a Ph diagram of the air conditioner according to the second embodiment. As shown in FIG. 10, by having the liquid receiver 285 that stores the liquid refrigerant, the refrigerant flowing out from the outdoor heat exchanger 230 is saturated without being supercooled when the air conditioner performs cooling operation. becomes liquid. Therefore, the refrigerant flows out of the outdoor heat exchanger 230 without being supercooled even if the control device 400 does not perform control related to supercooling.

As described above, the air conditioner of Embodiment 2 is configured to include the liquid receiver 285 between the outdoor heat exchanger 230 and the auxiliary heat exchanger 240 . Therefore, the degree of supercooling of the refrigerant passing through the outdoor heat exchanger 230 can be suppressed without the control device 400 performing control related to supercooling by a device such as an actuator of the refrigerant circuit. Therefore, the liquid refrigerant does not stay in the outdoor heat exchanger 230, and deterioration of the condensation performance can be prevented. By ensuring the degree of subcooling of the refrigerant in the auxiliary heat exchanger 240, the cooling COP can be increased.

Embodiment 3.
11 is a diagram showing a configuration of an air conditioner according to Embodiment 3. FIG. In FIG. 11, devices and the like denoted by the same reference numerals as in FIG. 1 perform the same functions and operations as those described in the first embodiment. As shown in FIG. 11, the air conditioner of Embodiment 3 has a two-way valve 290. In FIG. The two-way valve 290 is a valve serving as an opening/closing device that controls whether the passage of the refrigerant to the heat exchanger 10A is allowed or restricted. Here, the air conditioner is described as having an opening/closing device in order to suppress pressure loss, but the present invention is not limited to this. A flow regulating device capable of regulating the flow rate of the refrigerant may be used instead of the opening/closing device.

The outdoor heat exchanger 230 functions as a condenser when the air conditioner performs cooling operation. Control device 400 performs control to reduce drive capacity by driving compressor 210 at a low rotational speed when the air conditioning load is small. At this time, the refrigerant circulation amount in the refrigerant circuit is reduced. In such a case, if the refrigerant flows into and out of both the heat exchanger 10A and the heat exchanger 10B, the pressure loss of the refrigerant increases and the flow velocity of the refrigerant slows down. Therefore, the air conditioner of Embodiment 3 has two-way valve 290 .

FIG. 12 is a diagram explaining the flow of opening/closing control of the two-way valve 290 performed by the control device 400 according to the third embodiment. When the air conditioner starts to operate, the control device 400 determines whether to perform the cooling operation or the heating operation (step S1). When the control device 400 determines that the air conditioner will perform the heating operation, the control device 400 opens the two-way valve 290 (step S5).

When the control device 400 determines that the air conditioner will perform the cooling operation, it detects the rotation speed of the motor of the compressor 210 (step S2). Here, control device 400 detects the number of revolutions of the motor, for example, based on the drive frequency related to the control of inverter device 215 . The control device 400 determines whether or not the detected rotation speed of the motor is equal to or higher than a preset rotation speed (step S3). When the control device 400 determines that the detected rotation speed of the motor is equal to or higher than the set rotation speed, the control device 400 opens the two-way valve 290 (step S5).

On the other hand, when the controller 400 determines that the detected number of rotations of the motor is less than the set number of rotations, it closes the two-way valve 290 (step S4). During the cooling operation, the control device 400 returns to step S2 and continues opening/closing control of the two-way valve 290 until it determines that the operation has ended (step S6).

As described above, the air conditioner of Embodiment 3 has the two-way valve 290 that restricts passage of refrigerant in a part of the outdoor heat exchanger 230 . Then, when the control device 400 determines that the rotational speed of the compressor 210 is low and the drive capacity is low when the air conditioner performs the cooling operation, the control device 400 closes the two-way valve 290 . Therefore, when the air conditioner performs cooling operation and the outdoor heat exchanger 230 functions as a condenser, the pressure loss of the refrigerant can be suppressed and the flow velocity can be prevented from decreasing. Therefore, the air conditioner can suppress a decrease in the cooling COP. Further, when the air conditioner performs heating operation and the outdoor heat exchanger 230 functions as an evaporator, the control device 400 opens the two-way valve 290 . Therefore, the air conditioner can have the heating COP in a state suitable for operation.

Embodiment 4.
13A and 13B are diagrams for explaining the flow of opening degree control of the expansion device 120 performed by the control device 400 according to the fourth embodiment. The equipment configuration of the air conditioner of Embodiment 4 is the same as that of the air conditioners described in Embodiments 1 to 3. FIG. In the air conditioner of Embodiment 4, when the outdoor heat exchanger 230 functions as a condenser, the control device 400 controls the opening degree of the expansion device 120, and the liquid refrigerant flowing out from the outdoor heat exchanger 230 is controlled so that the degree of supercooling is within the set range.

The control device 400 acquires the discharge pressure Pd detected by the discharge-side pressure sensor 510 (step S10). Then, the control device 400 calculates the condensation temperature CT of the refrigerant from the discharge pressure Pd (step S11).

Also, the control device 400 acquires the condensation outlet refrigerant temperature TCO detected by the inter-heat-exchanger temperature sensor 520 (step S12). Then, the controller 400 calculates the degree of subcooling SC (=condensing temperature CT-condensing outlet refrigerant temperature TCO), which is the difference between the condensation temperature CT and the condensation outlet refrigerant temperature TCO (step S13).

The control device 400 determines whether or not the calculated supercooling degree SC is smaller than the preset supercooling degree lower limit SC1 (step S14). When the control device 400 determines that the supercooling degree SC is smaller than the set supercooling degree lower limit SC1, the control device 400 performs control to reduce the opening degree of the expansion device 120 (step S16).

On the other hand, when the control device 400 determines that the degree of supercooling SC is not less than the set supercooling degree lower limit SC1 (is greater than or equal to the set supercooling degree lower limit SC1), the degree of supercooling SC reaches the preset set supercooling degree upper limit. It is determined whether it is greater than SC2 (step S15). When the controller 400 determines that the supercooling degree SC is not greater than the set supercooling degree upper limit SC2 (is equal to or less than the set supercooling degree upper limit SC2), it maintains the opening of the expansion device 120 (step S17). When the control device 400 determines that the supercooling degree SC is larger than the set supercooling degree upper limit SC2, it performs control to increase the opening of the expansion device 120 (step S18). When the preset time has elapsed (step S19), the control device 400 returns to step S10 and repeats the process.

As described above, according to the air conditioner of Embodiment 4, control device 400 controls the degree of supercooling of the liquid refrigerant flowing out of outdoor heat exchanger 230 to be within the set temperature range during cooling operation. to control. Therefore, it is possible to prevent the deterioration of the condensation performance due to the liquid refrigerant remaining in the outdoor heat exchanger 230, and suppress the deterioration of the cooling COP.

Embodiment 5.
FIG. 14 is a diagram illustrating the flow of control of the degree of opening of the refrigerant amount adjustment valve 250 performed by the control device 400 according to the fifth embodiment. The equipment configuration of the air conditioner of Embodiment 5 is the same as that of the air conditioners described in Embodiments 1 to 3. FIG. In the air conditioner of Embodiment 5, control device 400 controls the degree of opening of refrigerant amount adjustment valve 250 when outdoor heat exchanger 230 functions as a condenser. At this time, the controller 400 controls the temperature difference between the temperature of the liquid refrigerant passing between the outdoor heat exchanger 230 and the auxiliary heat exchanger 240 and the temperature of the refrigerant flowing out from the auxiliary heat exchanger 240 to the main refrigerant circuit. is within the set range.

The control device 400 acquires the condensation outlet refrigerant temperature TCO detected by the inter-heat-exchanger temperature sensor 520 (step S21). The control device 400 also acquires the supercooled refrigerant temperature ThO detected by the auxiliary heat exchanger temperature sensor 521 (step S22). Then, the control device 400 calculates the temperature difference Δth between the condensation outlet refrigerant temperature TCO and the supercooled refrigerant temperature ThO (=condensation outlet refrigerant temperature TCO−supercooled refrigerant temperature ThO) (step S23).

The control device 400 determines whether the calculated temperature difference Δth is smaller than the preset temperature difference lower limit ΔT1 (step S24). When determining that the temperature difference Δth is smaller than the temperature difference lower limit ΔT1, the control device 400 performs control to increase the opening degree of the refrigerant amount adjustment valve 250 (step S26).

On the other hand, when control device 400 determines that temperature difference Δth is not smaller than temperature difference lower limit ΔT1 (temperature difference Δth is equal to or greater than temperature difference lower limit ΔT1), temperature difference Δth is larger than preset temperature difference upper limit ΔT2. It is determined whether or not (step S25). When controller 400 determines that temperature difference Δth is not greater than temperature difference upper limit ΔT2 (is equal to or less than temperature difference upper limit ΔT2), control device 400 maintains the opening degree of refrigerant amount adjustment valve 250 (step S27). When the control device 400 determines that the temperature difference Δth is larger than the temperature difference upper limit ΔT2, it performs control to reduce the opening degree of the refrigerant amount adjustment valve 250 (step S28). When the preset time has elapsed (step S29), the control device 400 returns to step S21 and repeats the process.

As described above, according to the air conditioner of Embodiment 5, control device 400 controls the temperature of the liquid refrigerant passing between outdoor heat exchanger 230 and auxiliary heat exchanger 240 and the temperature of auxiliary heat exchanger 240 control is performed so that the temperature difference from the temperature of the refrigerant flowing out from to the main refrigerant circuit is within a set range. Therefore, even if the degree of supercooling of the liquid refrigerant flowing out of the outdoor heat exchanger 230 is small, the degree of supercooling can be ensured in the auxiliary heat exchanger 240, so that a decrease in the cooling COP can be suppressed. can.

Embodiment 6.
FIG. 15 is a diagram illustrating the flow of control of the degree of opening of the refrigerant amount adjusting valve 250 performed by the control device 400 according to the sixth embodiment. The equipment configuration of the air conditioner of Embodiment 6 is the same as that of the air conditioners described in Embodiments 1 to 3. FIG. In the air conditioner of Embodiment 6, control device 400 controls the degree of opening of refrigerant amount adjustment valve 250 when outdoor heat exchanger 230 functions as a condenser. At this time, control device 400 controls so that the degree of superheat of the refrigerant flowing out from auxiliary heat exchanger 240 to bypass pipe 260 is within a set range.

The control device 400 acquires the suction pressure Ps detected by the suction side pressure sensor 511 (step S30). Then, the control device 400 calculates the evaporation temperature ET of the refrigerant from the suction pressure Ps (step S31).

The control device 400 also acquires the bypass pipe temperature Thbo detected by the bypass pipe temperature sensor 522 (step S32). Then, the controller 400 calculates an auxiliary degree of superheat SHho (=bypass pipe temperature Thbo−evaporation temperature ET), which is the difference between the bypass pipe temperature Thbo and the evaporation temperature ET (step S33).

The control device 400 determines whether or not the calculated auxiliary superheat SHho is smaller than the preset superheat lower limit SHho1 (step S34). When the control device 400 determines that the auxiliary superheat SHho is smaller than the set superheat lower limit SHho1, the control device 400 performs control to reduce the opening degree of the refrigerant amount adjusting valve 250 (step S36).

When the control device 400 determines that the auxiliary superheat SHho is not less than the set superheat lower limit SHho1 (is greater than or equal to the set superheat lower limit SHho1), it further determines whether it is greater than a preset superheat upper limit SHho2. (step S35). When the control device 400 determines that the auxiliary degree of superheat SHho is not greater than the set superheat degree upper limit SHho2 (is equal to or less than the set superheat degree upper limit SHho2), it maintains the opening degree of the refrigerant amount control valve 250 (step S37). When the control device 400 determines that the auxiliary degree of superheat SHho is greater than the set superheat degree upper limit SHho2, the control device 400 performs control to increase the degree of opening of the refrigerant amount adjustment valve 250 (step S38). When the preset time has elapsed (step S39), the control device 400 returns to step S30 and repeats the process.

As described above, according to the air conditioner of Embodiment 6, the control device 400 controls the degree of superheat of the refrigerant flowing out from the auxiliary heat exchanger 240 to the bypass pipe 260 to be within the set range. Therefore, even if the degree of supercooling of the liquid refrigerant flowing out of the outdoor heat exchanger 230 is small, the degree of supercooling can be ensured in the auxiliary heat exchanger 240, so that a decrease in the cooling COP can be suppressed. can.

Embodiment 7.
FIG. 16 is a diagram illustrating the flow of control of the degree of opening of the refrigerant amount adjustment valve 250 performed by the control device 400 according to the seventh embodiment. The equipment configuration of the air conditioner of Embodiment 7 is the same as that of the air conditioners described in Embodiments 1 to 3. FIG. In the air conditioner of Embodiment 7, control device 400 controls the degree of opening of refrigerant amount adjustment valve 250 when outdoor heat exchanger 230 functions as a condenser. At this time, the control device 400 controls so that the degree of subcooling of the liquid refrigerant flowing out from the auxiliary heat exchanger 240 to the main refrigerant circuit is within a set range.

The control device 400 acquires the discharge pressure Pd detected by the discharge side pressure sensor 510 (step S40). Then, the control device 400 calculates the condensation temperature CT of the refrigerant from the discharge pressure Pd (step S41).

The control device 400 also acquires the supercooled refrigerant temperature ThO detected by the auxiliary heat exchanger temperature sensor 521 (step S42). Then, the control device 400 calculates an auxiliary supercooling degree SChO (=condensing temperature CT-supercooled refrigerant temperature ThO), which is the difference between the condensation temperature CT and the supercooled refrigerant temperature ThO (step S43).

The control device 400 determines whether or not the calculated auxiliary supercooling degree SChO is smaller than the preset auxiliary-side supercooling degree lower limit SChO1 (step S44). When the control device 400 determines that the auxiliary supercooling degree SChO is smaller than the set auxiliary-side supercooling degree lower limit SChO1, the control device 400 performs control to reduce the opening degree of the refrigerant amount adjusting valve 250 (step S46).

In step S44, the control device 400 determines that the auxiliary supercooling degree SChO is not smaller than the set auxiliary-side supercooling degree lower limit SChO1 (is greater than or equal to the auxiliary-side supercooling degree lower limit SChO1). At this time, the control device 400 further determines whether or not the auxiliary degree of supercooling SChO is greater than a preset auxiliary-side supercooling degree upper limit SChO2 (step S45).

When the control device 400 determines that the auxiliary supercooling degree SChO is not greater than the set auxiliary supercooling degree upper limit SChO2 (below the set auxiliary supercooling degree upper limit SChO2), the control device 400 maintains the opening degree of the refrigerant amount adjustment valve 250. (step S47). When the control device 400 determines that the auxiliary supercooling degree SChO is larger than the set auxiliary supercooling degree upper limit SChO2, the control device 400 performs control to increase the opening degree of the refrigerant amount adjusting valve 250 (step S48). When the preset time has elapsed (step S49), the control device 400 returns to step S40 and repeats the process.

As described above, according to the air conditioner of Embodiment 7, the control device 400 controls the degree of subcooling of the liquid refrigerant flowing out from the auxiliary heat exchanger 240 to the main refrigerant circuit to be within the set range. . Therefore, even if the degree of supercooling of the liquid refrigerant flowing out of the outdoor heat exchanger 230 is small, the degree of supercooling can be ensured in the auxiliary heat exchanger 240, so that a decrease in the cooling COP can be suppressed. can.

Embodiment 8.
FIG. 17 is a diagram illustrating the flow of control of the degree of opening of the refrigerant amount adjusting valve 250 performed by the control device 400 according to the eighth embodiment. The equipment configuration of the air conditioner of the eighth embodiment is the same as that of the air conditioners described in the first to third embodiments. In the air conditioner of Embodiment 8, control device 400 controls the degree of opening of refrigerant amount adjustment valve 250 when outdoor heat exchanger 230 functions as a condenser. At this time, the control device 400 controls so that the degree of subcooling of the liquid refrigerant flowing out of the outdoor heat exchanger 230 is within a set range.

The control device 400 acquires the discharge pressure Pd detected by the discharge side pressure sensor 510 (step S50). Then, the control device 400 calculates the condensation temperature CT of the refrigerant from the discharge pressure Pd (step S51).

Also, the control device 400 acquires the condensation outlet refrigerant temperature TCO detected by the inter-heat-exchanger temperature sensor 520 (step S52). Then, the controller 400 calculates the degree of supercooling SC (=condensing temperature CT-condensing outlet refrigerant temperature TCO), which is the difference between the condensation temperature CT and the condensation outlet refrigerant temperature TCO (step S53).

The control device 400 determines whether or not the calculated supercooling degree SC is smaller than a preset supercooling degree lower limit SC1 (step S54). When the control device 400 determines that the subcooling degree SC is smaller than the set supercooling degree lower limit SC1, the controller 400 performs control to reduce the opening degree of the refrigerant amount adjusting valve 250 (step S56).

On the other hand, when the control device 400 determines that the degree of supercooling SC is not less than the set supercooling degree lower limit SC1 (is greater than or equal to the set supercooling degree lower limit SC1), the degree of supercooling SC reaches the preset set supercooling degree upper limit. It is determined whether or not it is greater than SC2 (step S55). When the control device 400 determines that the degree of subcooling SC is not greater than the set supercooling degree upper limit SC2 (is equal to or less than the set supercooling degree upper limit SC2), the control device 400 maintains the opening degree of the refrigerant amount adjustment valve 250 (step S57). . When the control device 400 determines that the subcooling degree SC is larger than the set supercooling degree upper limit SC2, the control device 400 performs control to increase the opening degree of the refrigerant amount adjustment valve 250 (step S58). When the preset time has elapsed (step S59), the control device 400 returns to step S50 and repeats the process.

As described above, according to the air conditioner of Embodiment 8, the control device 400 controls the degree of subcooling of the liquid refrigerant flowing out of the outdoor heat exchanger 230 to be within the set range. Therefore, even if the degree of supercooling of the liquid refrigerant flowing out of the outdoor heat exchanger 230 is small, the degree of supercooling can be ensured in the auxiliary heat exchanger 240, so that a decrease in the cooling COP can be suppressed. can.

Embodiment 9.
Auxiliary heat exchanger 240 in Embodiments 1 to 8 described above has been described as a heat exchanger between refrigerants that exchanges heat between refrigerants circulating in the refrigerant circuit, but is not limited to this. For example, the heat exchanger may exchange heat with an external fluid, such as external air, to supercool the refrigerant.

10, 10A, 10B heat exchangers, 11, 11A, 11B distribution headers, 12, 12A, 12B refrigerant inlet/outlet pipes, 13 return headers, 14 flat heat transfer tubes, 15 corrugated fins, 100 indoor units, 110 indoor heat exchangers, 120 expansion device, 130 indoor fan, 200 outdoor unit, 210 compressor, 215 inverter device, 220 four-way valve, 230 outdoor heat exchanger, 240 auxiliary heat exchanger, 250 refrigerant amount adjustment valve, 260 bypass pipe, 270 accumulator, 280 outdoor fan, 285 liquid receiver, 290 two-way valve, 300 refrigerant piping, 400 control device, 500 detector, 510 discharge side pressure sensor, 511 suction side pressure sensor, 520 temperature sensor between heat exchangers, 521 auxiliary heat exchange vessel temperature sensor, 522 bypass piping temperature sensor.

Claims

An outdoor unit configured to form a main refrigerant circuit by pipe connection with a load-side heat exchanger and an expansion device,
a compressor that compresses and discharges the sucked refrigerant;
a refrigerant flow switching device for switching the flow path of the refrigerant between cooling operation and heating operation;
an outdoor heat exchanger that exchanges heat between the refrigerant passing through the interior and an external fluid;
an auxiliary heat exchanger that supercools the refrigerant flowing out of the outdoor heat exchanger and flowing through the main refrigerant circuit in the cooling operation;
The outdoor heat exchanger is
a pair of headers spaced apart from each other in the vertical direction and through which the refrigerant passes;
A plurality of flat transmission conductors each having a flat shape in cross section, arranged between a pair of the headers so that the flat surfaces on the longitudinal sides of the flat shape are opposed to each other and spaced apart from each other, and having flow passages in which the refrigerant flows. a heat tube;
a plurality of corrugated fins disposed between two adjacent flat heat transfer tubes and joined to the flat heat transfer tubes at the flat surface;
The flat heat transfer tubes are arranged in a plurality of rows along the direction of flow of the external fluid, and one of the pair of headers transfers the refrigerant from the flat heat transfer tubes of one row to the flat heat transfer tubes of another row. An outdoor unit comprising a bridging turn-back header, wherein the number of times the refrigerant is bridged by the turn-back header is one.
The outdoor unit according to claim 1, comprising a liquid receiver that is installed between the outdoor heat exchanger and the auxiliary heat exchanger and stores the liquid refrigerant.
The outdoor heat exchanger has a plurality of heat exchangers connected in parallel to the main refrigerant circuit,
3. The outdoor unit according to claim 1, further comprising an opening/closing device that restricts or restricts passage of the refrigerant to some of the plurality of heat exchangers.
A control device for controlling opening and closing of the opening and closing device,
4. The outdoor unit according to claim 3, wherein, when the controller determines that the rotation speed of the compressor is lower than a preset rotation speed, the opening/closing device restricts passage of the refrigerant.
an inter-heat-exchanger temperature sensor that detects the temperature of the refrigerant between the outdoor heat exchanger and the auxiliary heat exchanger as a condensation outlet refrigerant temperature;
a discharge side pressure sensor that detects the pressure of the refrigerant discharged from the compressor as a discharge pressure;
The outdoor unit according to any one of claims 1 to 4, further comprising a control device that controls the degree of opening of the expansion device based on the condensation outlet refrigerant temperature and the discharge pressure.
The auxiliary heat exchanger is a heat exchanger between refrigerants that heat-exchanges the refrigerant flowing through two flow paths,
One end is connected to the piping between the auxiliary heat exchanger and the expansion device, the other end is connected to the piping connected to the suction side of the compressor, and the a bypass pipe serving as a bypass flow path for passing the refrigerant;
a refrigerant amount adjusting device that reduces the pressure of the refrigerant passing through the bypass pipe and adjusts the amount of refrigerant;
an inter-heat-exchanger temperature sensor that detects the temperature of the refrigerant between the outdoor heat exchanger and the auxiliary heat exchanger as a condensation outlet refrigerant temperature;
An auxiliary heat exchanger temperature sensor that detects the temperature of the refrigerant supercooled by the auxiliary heat exchanger as a supercooled refrigerant temperature,
A control device for controlling the refrigerant amount adjustment of the refrigerant flowing through the bypass pipe by the refrigerant amount adjusting device based on the condensation outlet refrigerant temperature and the subcooled refrigerant temperature. or the outdoor unit according to item 1.
The auxiliary heat exchanger is a heat exchanger between refrigerants that heat-exchanges the refrigerant flowing through two flow paths,
One end is connected to the piping between the auxiliary heat exchanger and the expansion device, the other end is connected to the piping connected to the suction side of the compressor, and the a bypass pipe serving as a bypass flow path for passing the refrigerant;
a refrigerant amount adjusting device that reduces the pressure of the refrigerant passing through the bypass pipe and adjusts the amount of refrigerant;
a bypass pipe temperature sensor that detects the temperature of the refrigerant passing through the bypass pipe as a bypass pipe temperature;
a suction side pressure sensor that detects the pressure of the refrigerant sucked by the compressor as a suction pressure;
and a control device for controlling the refrigerant amount adjustment of the refrigerant flowing through the bypass pipe by the refrigerant amount adjusting device based on the bypass pipe temperature and the suction pressure. The outdoor unit described in .
The auxiliary heat exchanger is a heat exchanger between refrigerants that heat-exchanges the refrigerant flowing through two flow paths,
One end is connected to the piping between the auxiliary heat exchanger and the expansion device, the other end is connected to the piping connected to the suction side of the compressor, and the a bypass pipe serving as a bypass flow path for passing the refrigerant;
a refrigerant amount adjusting device that reduces the pressure of the refrigerant passing through the bypass pipe and adjusts the amount of refrigerant;
an auxiliary heat exchanger temperature sensor that detects the temperature of the refrigerant supercooled by the auxiliary heat exchanger as a supercooled refrigerant temperature;
a discharge side pressure sensor that detects the pressure of the refrigerant discharged from the compressor as a discharge pressure;
A control device for controlling the refrigerant amount adjustment of the refrigerant flowing through the bypass pipe by the refrigerant amount adjusting device based on the supercooled refrigerant temperature and the discharge pressure. The outdoor unit described in the paragraph.
The auxiliary heat exchanger is a heat exchanger between refrigerants that heat-exchanges the refrigerant flowing through two flow paths,
One end is connected to the piping between the auxiliary heat exchanger and the expansion device, the other end is connected to the piping connected to the suction side of the compressor, and the a bypass pipe serving as a bypass flow path for passing the refrigerant;
a refrigerant amount adjusting device that reduces the pressure of the refrigerant passing through the bypass pipe and adjusts the amount of refrigerant;
an inter-heat-exchanger temperature sensor that detects the temperature of the refrigerant between the outdoor heat exchanger and the auxiliary heat exchanger as a condensation outlet refrigerant temperature;
a discharge side pressure sensor that detects the pressure of the refrigerant discharged from the compressor as a discharge pressure;
A control device for controlling the refrigerant amount adjustment of the refrigerant flowing through the bypass pipe by the refrigerant amount adjusting device based on the condensation outlet refrigerant temperature and the discharge pressure. The outdoor unit described in the paragraph.
The outdoor unit according to any one of claims 1 to 9, wherein the distance between the pair of headers in the outdoor heat exchanger is 800 mm or more.
The outdoor unit according to any one of claims 1 to 10,
An air conditioner comprising an indoor unit that has a load-side heat exchanger and an expansion device and that conditions air in a space to be air-conditioned.