Refrigeration cycle apparatus

Abstract

This refrigeration cycle apparatus includes a refrigerant circuit in which a compressor, a condenser, a throttle device, and an evaporator are connected by a refrigerant pipe and in which a refrigerant circulates. The condenser includes: a heat exchange body which is formed by a flat tube group including a plurality of flat tubes disposed upright in a vertical direction and arranged side by side at intervals in a direction orthogonal to an air circulation direction and a corrugated fin disposed between the flat tubes adjacent to each other; a first header disposed at an upper end or a lower end of the flat tube group and provided with a refrigerant inflow port; a second header disposed at the upper end or the lower end of the flat tube group and provided with a refrigerant outflow port; a first temperature sensor which detects the temperature of the refrigerant in a refrigerant flow path between the first header and the second header and is provided at a position separated from the first header and the second header; and a second temperature sensor which is provided in the second header or a refrigerant outflow pipe connected to the refrigerant outflow port.

Description

Refrigeration cycle device

[0001] The present disclosure relates to a refrigeration cycle device including a condenser and an evaporator.

[0002] Conventionally, there is a refrigeration cycle device including a refrigerant circuit in which a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger are connected by refrigerant pipes and refrigerant circulates (see, for example, Patent Document 1).

[0003] In such a refrigeration cycle device, when performing a cooling operation, by accurately obtaining the degree of subcooling (subcool) at the outlet of the outdoor heat exchanger that functions as a condenser, the operation can be controlled so that the performance of the heat exchanger is improved.

[0004] International Publication No. 2013 / 080914

[0005] The outdoor heat exchanger of Patent Document 1 is composed of a plurality of flat tubes arranged vertically and side by side at intervals in a direction orthogonal to the air flow direction, and includes a plurality of flat tube groups arranged at intervals in the air flow direction, and a pair of headers arranged above and below each of the plurality of flat tube groups. In order to obtain the degree of subcooling (subcool), it is necessary to provide a temperature sensor in the outdoor heat exchanger that functions as a condenser. However, in an outdoor heat exchanger such as that of Patent Document 1, the temperature change is likely to be large in the single-phase region depending on the position where the temperature sensor is provided. Therefore, there is a problem that the degree of subcooling (subcool) cannot be accurately obtained, the controllability is reduced, and the performance of the heat exchanger is reduced.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to provide a refrigeration cycle device capable of accurately obtaining the degree of subcooling (subcool).

[0007] The refrigeration cycle apparatus according to this disclosure comprises a compressor, a condenser, a throttle device, and an evaporator connected by refrigerant piping, and a refrigerant circuit through which the refrigerant circulates. The condenser consists of a plurality of flat tubes arranged vertically in the vertical direction and spaced apart in a direction perpendicular to the airflow direction. The heat exchanger comprises a group of flat tubes spaced apart in the airflow direction and corrugated fins arranged between each adjacent flat tube. The apparatus also includes a first header located at the upper or lower end of the group of flat tubes and having a refrigerant inlet, a second header located at the upper or lower end of the group of flat tubes and having a refrigerant outlet, a first temperature sensor located away from the first and second headers for detecting the refrigerant temperature in the refrigerant flow path between the first and second headers, and a second temperature sensor located in a refrigerant outlet pipe connected to the second header or the refrigerant outlet.

[0008] According to the refrigeration cycle device described herein, the first temperature sensor is located away from the first and second headers in the condenser, where temperature changes tend to be large in the single-phase region, making it possible to accurately determine the degree of subcooling.

[0009] This is a refrigerant circuit diagram showing a refrigeration cycle device according to Embodiment 1. This is a schematic front view showing a condenser according to Embodiment 1. This is a schematic side view showing a condenser according to Embodiment 1. This is a schematic diagram illustrating the installation position of the first temperature sensor of the condenser according to Embodiment 1. This is a diagram showing the temperature relative to the position of the refrigerant path of the heat exchanger of the condenser according to Embodiment 1. This is a diagram showing the temperature relative to the position of the refrigerant path of the condenser according to Embodiment 1. This is a schematic front view showing a condenser according to Embodiment 2. This is a schematic front view showing a modified version of the condenser according to Embodiment 2. This is a schematic front view showing a condenser according to Embodiment 3. This is a schematic front view showing a modified version of the condenser according to Embodiment 3. This is a schematic side view showing a condenser according to Embodiment 4. This is an enlarged cross-sectional side perspective view of the upper part of the condenser according to Embodiment 4. This is a schematic diagram illustrating the installation position of the third temperature sensor of the condenser according to Embodiment 5. This is a refrigerant circuit diagram showing a refrigeration cycle device according to Embodiment 6.

[0010] The embodiments of this disclosure will be described below with reference to the drawings. However, the embodiments described below do not limit this disclosure. Also, the size relationships of the components in the following drawings may differ from those of the actual components. In addition, in the following description, terms indicating direction, such as "up," "down," "right," "left," "front," and "back," will be used as appropriate to facilitate understanding, but these are for illustrative purposes only and do not limit the embodiments. In the embodiments, "up," "down," "right," "left," "front," and "back" will be used when viewing the heat exchanger from the front.

[0011] Embodiment 1. <Configuration of Refrigeration Cycle Device 100> Figure 1 is a refrigerant circuit diagram showing a refrigeration cycle device 100 according to Embodiment 1.

[0012] First, the refrigeration cycle device 100 will be described using Figure 1. The refrigeration cycle device 100 is used for refrigeration or air conditioning applications, such as refrigerators or freezers, vending machines, air conditioning systems, refrigeration systems, and water heaters. Note that the refrigerant circuit 101 shown is just one example, and the configuration of the circuit elements is not limited to what has been described in the embodiment, and can be modified as appropriate within the scope of the technology relating to the embodiment.

[0013] As shown in Figure 1, the refrigeration cycle device 100 according to Embodiment 1 includes a compressor 11, a condenser 30, a first fan 12, a throttle device 13, an evaporator 14, a second fan 15, and a control device 50.

[0014] Furthermore, the refrigeration cycle device 100 includes a refrigerant circuit 101 through which the refrigerant circulates, with the compressor 11, condenser 30, throttle device 13, and evaporator 14 connected by refrigerant piping. The refrigeration cycle device 100 may also be equipped with a flow path switching device, such as a four-way valve, and configured to allow both cooling and heating operations by switching the flow path switching device.

[0015] The refrigerant circulating in the refrigerant circuit 101 is a single refrigerant from among R1234yf, R1234ze, and R290, or a mixture of two or more of these, or a mixture of one of these with another refrigerant, or a mixture containing R1132(E), or a mixture containing R1123. By using the above refrigerants, the low boiling point refrigerants have a low vapor density and a high flow velocity, which increases the effect of inertial force, thus greatly improving the refrigerant distribution performance. In addition, with mixed refrigerants, concentration variations occur as the distribution deteriorates, so the effect of performance improvement through improved refrigerant distribution performance can be greatly increased.

[0016] The compressor 11 draws in a low-temperature, low-pressure refrigerant, compresses the drawn-in refrigerant, and discharges a high-temperature, high-pressure refrigerant. The compressor 11 is, for example, an inverter compressor whose capacity, which is the amount of refrigerant delivered per unit time, is controlled by changing the operating frequency.

[0017] The condenser 30 performs heat exchange between the air and the refrigerant. The condenser 30 releases heat from the refrigerant into the air, causing the refrigerant to condense.

[0018] The first fan 12 supplies air to the condenser 30, and the amount of air supplied to the condenser 30 is adjusted by controlling its rotation speed.

[0019] The throttling device 13 is, for example, an electronic expansion valve that can adjust the throttling opening, and by adjusting the opening, it controls the pressure of the refrigerant flowing into the evaporator 14.

[0020] The evaporator 14 performs heat exchange between the air and the refrigerant. The evaporator 14 evaporates the refrigerant, and the heat of vaporization used in the process cools the air.

[0021] The second fan 15 supplies air to the evaporator 14, and the amount of air supplied to the evaporator 14 is adjusted by controlling its rotation speed.

[0022] The control device 50 consists of, for example, a CPU (also known as a Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, or processor) that executes a program stored in dedicated hardware or a memory unit (not shown).

[0023] If the control device 50 is dedicated hardware, it may be, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Each of the functional units realized by the control device 50 may be realized by individual hardware, or each functional unit may be realized by a single piece of hardware.

[0024] When the control device 50 is a CPU, each function performed by the control device 50 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory unit. The CPU realizes each function of the control device 50 by reading and executing the programs stored in the memory unit. Here, the memory unit stores various types of information and includes, for example, non-volatile semiconductor memory with rewritable data, such as flash memory, EPROM, and EEPROM.

[0025] Furthermore, some of the functions of the control device 50 may be implemented using dedicated hardware, while other functions may be implemented using software or firmware.

[0026] The control device 50 controls the compressor 11 and the throttle device 13, etc., based on detection signals from various sensors (not shown) provided in the refrigeration cycle device 100, and operation signals from an operation unit (not shown), thereby controlling the operation of the entire refrigeration cycle device 100.

[0027] Figure 2 is a schematic front view showing the condenser 30 according to Embodiment 1. Figure 3 is a schematic side view showing the condenser 30 according to Embodiment 1. Figure 4 is a schematic diagram illustrating the installation position of the first temperature sensor 61 of the condenser 30 according to Embodiment 1. The black arrows in Figures 2 to 4 indicate the refrigerant flow, and the white arrows in Figure 3 indicate the air flow direction.

[0028] As shown in Figures 2 and 3, the condenser 30 according to Embodiment 1 includes a heat exchanger 37 composed of a group of flat tubes 31, which consists of a plurality of flat tubes 38 arranged vertically in the vertical direction and spaced apart in the horizontal direction perpendicular to the air flow direction, and corrugated fins 39 arranged between each adjacent flat tube 38.

[0029] Furthermore, the condenser 30 is equipped with a pair of headers positioned above and below the flattened tube group 31. The pair of headers consists of a first header 34 and a second header 35, with the upper end of the flattened tube group 31 inserted into the first header 34 and the lower end of the flattened tube group 31 inserted into the second header 35. A first opening 34a, which is a refrigerant inlet, is formed at one end of the first header 34, and a refrigerant inlet pipe 41 is connected to the first opening 34a. A second opening 35a, which is a refrigerant outlet, is formed at one end of the second header 35, and a refrigerant outlet pipe 42 is connected to the second opening 35a. Gaseous refrigerant flows in from the first opening 34a of the first header 34, flows through the first header 34, the flattened tube group 31, and the second header 35 in that order, and liquid refrigerant flows out from the second opening 35a of the second header 35.

[0030] As shown in Figures 2 and 4, the condenser 30 is equipped with a first temperature sensor 61 and a second temperature sensor 62 for detecting the refrigerant temperature. The first temperature sensor 61 and the second temperature sensor 62 are, for example, thermistors. The second temperature sensor 62 is also provided in the refrigerant outlet pipe 42. The second temperature sensor 62 may be provided in the second header 35 or in the refrigerant piping connected to the refrigerant outlet pipe 42. The first temperature sensor 61 detects the refrigerant temperature in the refrigerant flow path between the first header 34 and the second header 35, and detects the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. The second temperature sensor 62 detects the refrigerant temperature in the refrigerant flow path inside the second header 35, the refrigerant outlet pipe 42, or the refrigerant piping connected to the refrigerant outlet pipe 42, and detects the temperature of the liquid refrigerant. Therefore, the degree of subcooling can be determined from the difference between the temperature detected by the second temperature sensor 62 and the temperature detected by the first temperature sensor 61.

[0031] Figure 5 is a diagram showing the temperature of the heat exchanger 37 of the condenser 30 with respect to its position in the refrigerant path according to Embodiment 1. Here, Figure 5 is an example of experimental results showing the relationship between the vertical position of the heat exchanger 37 of the condenser 30 and the refrigerant temperature under conditions where the degree of subcooling is 1.6, 3.4, 5.3, 8.8, and 11.8. The upper end position of the heat exchanger 37 in the vertical direction is set to 0%, and the lower end position is set to 100% (see Figure 4). According to this, in order to improve the performance of the refrigeration cycle device 100, it is necessary to find an appropriate degree of subcooling. As shown in Figure 5, even when the degree of subcooling changes from a small condition (1.6) to a large condition (11.8), it can be confirmed that there is no temperature change at the 30-70% position in the vertical direction of the heat exchanger 37, and it is in the gas-liquid two-phase region.

[0032] In the condenser 30 according to Embodiment 1, gaseous refrigerant flows in from the first opening 34a of the first header 34 and flows through the first header 34, the flat tube group 31, and the second header 35 in that order. As the refrigerant exchanges heat with air and condenses, liquid refrigerant flows out from the second opening 35a of the second header 35. Therefore, near the first header 34, the refrigerant remains in gaseous form, and it may not be possible to detect the temperature of the gas-liquid two-phase refrigerant. Also, near the second header 35, the refrigerant becomes liquid, and it may not be possible to detect the temperature of the gas-liquid two-phase refrigerant. Furthermore, if a region close to the pair of headers, where it is prone to becoming single-phase and temperature changes are likely to occur, is detected, the difference with the temperature detected by the second temperature sensor 62 becomes unstable, and it becomes impossible to accurately determine the degree of subcooling. Therefore, as shown in Figure 4, if the upper end of the heat exchanger 37 is defined as 0% and the lower end as 100%, at least a portion of the first temperature sensor 61 is placed at a position 30-70% in the vertical direction of the heat exchanger 37, away from the first header 34 and the second header 35. By doing so, the temperature of the gas-liquid two-phase refrigerant can be detected more reliably, and the degree of subcooling can be accurately determined.

[0033] Figure 6 shows the temperature as a function of the refrigerant path in the condenser 30 according to Embodiment 1. Here, gaseous refrigerant flows from the refrigerant inlet pipe 41 to the first opening 34a of the first header 34, and as it flows through the first header 34, the flattened tube group 31, and the second header 35, the refrigerant exchanges heat with air and condenses, and liquid refrigerant flows out from the second opening 35a of the second header 35 to the refrigerant outlet pipe 42. The shortest flow path of the refrigerant path in the condenser 30 is in the order of P3, P2, PA, P1, PC, P0 as shown in Figure 4, and the longest flow path of the refrigerant path in the condenser 30 is in the order of P3, P2, P5, PB, P4, P1, PC, P0 as shown in Figure 4. The flow of refrigerant in the flattened tube 38 depends on the magnitude of the pressure difference between the upper and lower ends. Also, because the gaseous refrigerant flowing from the refrigerant inlet pipe 41 to the first opening 34a of the first header 34 has a large volume, the loss in the header tends to be larger than that of liquid refrigerant. Furthermore, in the flattened pipes 38 distributed from the same header space, the pressure difference between the upper and lower ends tends to be smaller on the side farther from the first opening 34a, which is the refrigerant inlet. As a result, the refrigerant flow velocity is lower on the side farther from the first opening 34a and higher on the side closer to the first opening 34a. Consequently, more refrigerant flows on the side closer to the first opening 34a where the refrigerant flow velocity is higher, and less refrigerant flows on the side farther from the first opening 34a where the refrigerant flow velocity is lower. Therefore, the side farther from the first opening 34a where the refrigerant flow velocity is lower is prone to becoming single-phase. As shown in Figure 6, when the first temperature sensor 61 is installed at position PB, which is the position furthest from the first opening 34a in the horizontal direction of the heat exchanger 37, it is prone to becoming single-phase and temperature changes are likely to occur. As a result, the difference between the detected temperature at PC, where the second temperature sensor 62 is installed, and the first temperature sensor 61 is installed becomes unstable, and the degree of subcooling cannot be accurately determined. On the other hand, if the first temperature sensor 61 is placed at PA, which is the position closest to the first opening 34a in the horizontal direction of the heat exchanger 37, it will be in a gas-liquid two-phase region and no temperature change will occur. Therefore, as shown in Figure 4, if the position closest to the first opening 34a in the horizontal direction of the heat exchanger 37 is defined as 0%, and the position furthest from the first opening 34a is defined as 100%, then at least a part of the first temperature sensor 61 is placed at a position between 0% and 50% in the horizontal direction of the heat exchanger 37. By doing so, the temperature of the gas-liquid two-phase refrigerant can be detected more reliably, and the degree of subcooling can be determined more accurately.

[0034] Furthermore, the refrigerant flow velocity is highest in the shortest path of the refrigerant flow path in the condenser 30 (in the order of P3, P2, PA, P1, PC, P0 shown in Figure 4), and it is most likely to be in the gas-liquid two-phase region. Among the group of flattened tubes 31, the flattened tube 38 located closest to the first opening 34a constitutes the shortest path of the refrigerant flow path in the condenser 30. Therefore, by installing the first temperature sensor 61 on the flattened tube 38 located closest to the first opening 34a among the group of flattened tubes 31, the degree of subcooling can be determined more accurately.

[0035] The refrigeration cycle device 100 according to Embodiment 1 is a refrigeration cycle device 100 comprising a compressor 11, a condenser 30, a throttle device 13, and an evaporator 14 connected by refrigerant piping, and a refrigerant circuit 101 through which the refrigerant circulates, wherein the condenser 30 consists of a plurality of flat tubes 38 arranged vertically in the vertical direction and spaced apart in a direction perpendicular to the air flow direction, and a heat exchanger composed of a group of flat tubes 31 spaced apart in the air flow direction and corrugated fins 39 arranged between each adjacent flat tube 38 The device comprises 37, a first header 34 positioned at the upper or lower end of the flattened pipe group 31 and having a refrigerant inlet, a second header 35 positioned at the upper or lower end of the flattened pipe group 31 and having a refrigerant outlet, a first temperature sensor 61 positioned away from the first header 34 and the second header 35 for detecting the refrigerant temperature in the refrigerant flow path between the first header 34 and the second header 35, and a second temperature sensor 62 provided on the refrigerant outlet pipe 42 connected to the second header 35 or the refrigerant outlet.

[0036] According to the refrigeration cycle device 100 of Embodiment 1, the first temperature sensor 61 is provided in the condenser 30 at a position away from the first header 34 and the second header 35, where temperature changes tend to be large in the single-phase region, so the degree of subcooling can be accurately determined.

[0037] Furthermore, in the refrigeration cycle device 100 according to Embodiment 1, if the upper end position of the heat exchanger 37 is defined as 0% and the lower end position as 100%, the first temperature sensor 61 is provided at a position between 30% and 70% in the vertical direction of the heat exchanger 37.

[0038] According to the refrigeration cycle device 100 of Embodiment 1, the first temperature sensor 61 is installed at a position 30-70% in the vertical direction of the heat exchanger 37. This allows for more reliable detection of the temperature of the gas-liquid two-phase refrigerant, and enables more accurate determination of the degree of subcooling.

[0039] Furthermore, in the refrigeration cycle device 100 according to Embodiment 1, if the position closest to the refrigerant inlet in the horizontal direction of the heat exchanger 37 is defined as 0%, and the position furthest from the refrigerant inlet is defined as 100%, then the first temperature sensor 61 is provided at a position between 0% and 50% in the horizontal direction of the heat exchanger 37.

[0040] According to the refrigeration cycle device 100 of Embodiment 1, the first temperature sensor 61 is installed at a position between 0% and 50% in the horizontal direction of the heat exchanger 37. This allows for more reliable detection of the temperature of the gas-liquid two-phase refrigerant, and enables more accurate determination of the degree of subcooling.

[0041] Furthermore, in the refrigeration cycle device 100 according to Embodiment 1, the first temperature sensor 61 is provided on the flat tube 38 located in the position closest to the refrigerant inlet among the group of flat tubes 31.

[0042] According to the refrigeration cycle device 100 of Embodiment 1, the first temperature sensor 61 is installed on a flat tube 38 located in the flat tube group 31, which is the position closest to the refrigerant inlet, and is the position where the gas-liquid two-phase region is most likely to occur. Therefore, the degree of subcooling can be determined more accurately.

[0043] Furthermore, in the refrigeration cycle device 100 according to Embodiment 1, the first temperature sensor 61 is supported by the corrugated fin 39.

[0044] According to the refrigeration cycle device 100 according to Embodiment 1, by providing the first temperature sensor 61 so as to be supported by the corrugated fin 39, the first temperature sensor 61 can be easily installed.

[0045] Further, the refrigeration cycle device 100 according to Embodiment 1 uses a single refrigerant of any one of R1234yf, R1234ze, and R290, or a mixed refrigerant of any two or more of these, or a mixed refrigerant of any of these and another refrigerant, a mixed refrigerant containing R1132(E), or a mixed refrigerant containing R1123.

[0046] According to the refrigeration cycle device 100 according to Embodiment 1, by using the above refrigerant, since the low-boiling refrigerant has a small vapor density and a high flow velocity, the influence of the inertial force becomes large, so the effect of improving the distribution performance of the refrigerant can be increased. In addition, in the mixed refrigerant, as the distribution deteriorates, a concentration variation occurs, so the effect of improving the performance due to the improvement of the distribution performance of the refrigerant can be increased.

[0047] Embodiment 2. Hereinafter, Embodiment 2 will be described. However, the description of the parts overlapping with Embodiment 1 will be omitted, and the same reference numerals will be given to the same parts or corresponding parts as those in Embodiment 1.

[0048] FIG. 7 is a front view schematically showing the condenser 30 according to Embodiment 2. The black arrows in FIG. 7 indicate the refrigerant flow.

[0049] As shown in FIG. 7, the condenser 30 according to Embodiment 2 includes a flat tube group 31 composed of a plurality of flat tubes 38 arranged vertically and spaced apart in the horizontal direction orthogonal to the air flow direction, and a heat exchanger 37 composed of corrugated fins 39 arranged between adjacent flat tubes 38.

[0050] Furthermore, the condenser 30 is equipped with a pair of headers positioned above and below the group of flat tubes 31. The pair of headers consists of a first header 34 and a second header 35, and an intermediate header 36. The first header 34 and the second header 35 are formed by dividing one header with a partition 43, and the upper end of the group of flat tubes 31 is inserted into the first header 34 and the second header 35. The lower end of the group of flat tubes 31 is inserted into the intermediate header 36. A first opening 34a, which is a refrigerant inlet, is formed at one end of the first header 34, and a refrigerant inlet pipe 41 is connected to the first opening 34a. A second opening 35a, which is a refrigerant outlet, is formed at one end of the second header 35, and a refrigerant outlet pipe 42 is connected to the second opening 35a. In the following, the group of flat tubes 31 inserted into the first header 34 will be referred to as the first group of flat tubes, and the group of flat tubes 31 inserted into the second header 35 will be referred to as the second group of flat tubes. Furthermore, the first group of flat tubes and the corrugated fins 39 arranged between each adjacent flat tube 38 will be referred to as the first heat exchanger 37A, and the second group of flat tubes and the corrugated fins 39 arranged between each adjacent flat tube 38 will be referred to as the second heat exchanger 37B.

[0051] Gaseous refrigerant flows in from the first opening 34a of the first header 34, and flows in the order of the first header 34, the first flattened tube group, the intermediate header 36, the second flattened tube group, and the second header 35, and liquid refrigerant flows out from the second opening 35a of the second header 35.

[0052] As shown in Figure 7, the condenser 30 is equipped with a first temperature sensor 61 and a second temperature sensor 62 for detecting the refrigerant temperature. The first temperature sensor 61 and the second temperature sensor 62 are, for example, thermistors. The second temperature sensor 62 is also provided in the refrigerant outlet pipe 42. The second temperature sensor 62 may be provided in the second header 35 or in the refrigerant piping connected to the refrigerant outlet pipe 42. The first temperature sensor 61 detects the refrigerant temperature in the refrigerant flow path between the first header 34 and the second header 35, and detects the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. The second temperature sensor 62 detects the refrigerant temperature in the refrigerant flow path inside the second header 35, the refrigerant outlet pipe 42, or the refrigerant piping connected to the refrigerant outlet pipe 42, and detects the temperature of the liquid refrigerant. Therefore, the degree of subcooling can be determined from the difference between the temperature detected by the second temperature sensor 62 and the temperature detected by the first temperature sensor 61.

[0053] Here, gaseous refrigerant flows from the refrigerant inlet pipe 41 to the first opening 34a of the first header 34, and as it flows in the order of the first header 34, the first flattened pipe group, the intermediate header 36, the second flattened pipe group, and the second header 35, the refrigerant exchanges heat with the air and condenses, and liquid refrigerant flows out from the second opening 35a of the second header 35 to the refrigerant outlet pipe 42. In a configuration where at least one of the pair of headers is separated by a partition 43 and the refrigerant is reversed at the intermediate header 36, the refrigerant tends to become liquid in the region downstream of the intermediate header 36, which is the turning point of the refrigerant flow path. On the other hand, in the region upstream of the intermediate header 36, the refrigerant tends to become a gas-liquid two-phase refrigerant, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. Therefore, by placing the first temperature sensor 61 in a part of the first heat exchanger 37A, which is the upstream region, the gas-liquid two-phase region is widened, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. As a result, the degree of subcooling can be determined more accurately under a wide range of refrigerant flow rate conditions. In configurations where multiple partitions 43 are provided in a pair of headers, it is preferable to place the first temperature sensor 61 in the most upstream region.

[0054] Figure 8 is a schematic front view showing a modified example of the condenser 30 according to Embodiment 2. Although the first temperature sensor 61 was described above as being provided in a part of the first heat exchanger 37A, which is the upstream region, it is not limited to this. Since the gas-liquid two-phase refrigerant is more likely to form in the region within the intermediate header 36, and the temperature (saturation temperature) of the gas-liquid two-phase refrigerant is easier to detect, it may also be provided in the intermediate header 36 as shown in Figure 8. By providing the first temperature sensor 61 in the intermediate header 36 in this way, it is possible to suppress the deterioration of heat exchanger performance due to airflow blockage and heat transfer inhibition caused by the sensor.

[0055] In the refrigeration cycle device 100 according to Embodiment 2, a first header 34 and a second header 35 are arranged at one of the upper and lower ends of the flattened tube group 31, an intermediate header 36 is arranged at the other of the upper and lower ends of the flattened tube group 31, and a partition 43 for reversing the flow path is provided between the first header 34 and the second header 35.

[0056] Furthermore, in the refrigeration cycle device 100 according to Embodiment 2, the first temperature sensor 61 is provided in the group of flattened tubes 31 connected to the first header 34.

[0057] According to the refrigeration cycle device 100 of Embodiment 2, by providing the first temperature sensor 61 in a part of the first heat exchanger 37A, which is the upstream region, the gas-liquid two-phase region is widened, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. As a result, the degree of subcooling can be determined more accurately under a wide range of refrigerant flow rate conditions.

[0058] Furthermore, in the refrigeration cycle device 100 according to Embodiment 2, the first temperature sensor 61 is provided in the intermediate header 36.

[0059] According to the refrigeration cycle device 100 of Embodiment 2, by providing the first temperature sensor 61 in the intermediate header 36, the gas-liquid two-phase region is widened, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant, thus enabling more accurate determination of the degree of subcooling under a wide range of refrigerant flow rate conditions. Furthermore, by providing the first temperature sensor 61 in the intermediate header 36, it is possible to suppress the deterioration of heat exchanger performance due to airflow blockage and heat transfer inhibition caused by the sensor.

[0060] Embodiment 3. Embodiment 3 will be described below, but the description of parts that overlap with Embodiments 1 and 2 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 and 2.

[0061] Figure 9 is a schematic front view showing the condenser 30 according to Embodiment 3. The black arrows in Figure 9 indicate the refrigerant flow.

[0062] As shown in Figure 9, the condenser 30 according to Embodiment 3 includes a heat exchanger 37 composed of a group of flat tubes 31, which consists of a plurality of flat tubes 38 arranged vertically in the vertical direction and spaced apart in the horizontal direction perpendicular to the air flow direction, and corrugated fins 39 arranged between each adjacent flat tube 38.

[0063] Furthermore, the condenser 30 is equipped with a pair of headers positioned above and below the group of flat tubes 31. The pair of headers consists of a first header 34 and a second header 35, and an intermediate header 36. The first header 34 and the second header 35 are formed by dividing one header with a partition 43, and the lower end of the group of flat tubes 31 is inserted into the first header 34 and the second header 35. The upper end of the group of flat tubes 31 is inserted into the intermediate header 36. In other words, in the condenser 30 according to Embodiment 3, the positions of the first header 34 and the second header 35 and the intermediate header 36 are reversed vertically compared to the condenser 30 according to Embodiment 2. A first opening 34a, which is a refrigerant inlet, is formed at one end of the first header 34, and a refrigerant inlet pipe 41 is connected to the first opening 34a. A second opening 35a, which is a refrigerant outlet, is formed at one end of the second header 35, and a refrigerant outlet pipe 42 is connected to the second opening 35a. In the following, the group of flat tubes 31 inserted into the first header 34 will be referred to as the first group of flat tubes, and the group of flat tubes 31 inserted into the second header 35 will be referred to as the second group of flat tubes. Furthermore, the first group of flat tubes and the corrugated fins 39 arranged between each adjacent flat tube 38 will be referred to as the first heat exchanger 37A, and the second group of flat tubes and the corrugated fins 39 arranged between each adjacent flat tube 38 will be referred to as the second heat exchanger 37B.

[0064] Gaseous refrigerant flows in from the first opening 34a of the first header 34, and flows in the order of the first header 34, the first flattened tube group, the intermediate header 36, the second flattened tube group, and the second header 35, and liquid refrigerant flows out from the second opening 35a of the second header 35.

[0065] As shown in Figure 9, the condenser 30 is equipped with a first temperature sensor 61 and a second temperature sensor 62 for detecting the refrigerant temperature. The first temperature sensor 61 and the second temperature sensor 62 are, for example, thermistors. The second temperature sensor 62 is also provided in the refrigerant outlet pipe 42. The second temperature sensor 62 may also be provided in the second header 35 or in the refrigerant piping connected to the refrigerant outlet pipe 42. The first temperature sensor 61 detects the refrigerant temperature in the refrigerant flow path between the first header 34 and the second header 35, and detects the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. The second temperature sensor 62 detects the refrigerant temperature in the refrigerant flow path inside the second header 35, the refrigerant outlet pipe 42, or the refrigerant piping connected to the refrigerant outlet pipe 42, and detects the temperature of the liquid refrigerant. Therefore, the degree of subcooling can be determined from the difference between the temperature detected by the second temperature sensor 62 and the temperature detected by the first temperature sensor 61.

[0066] Here, gaseous refrigerant flows from the refrigerant inlet pipe 41 to the first opening 34a of the first header 34, and as it flows in the order of the first header 34, the first flattened pipe group, the intermediate header 36, the second flattened pipe group, and the second header 35, the refrigerant exchanges heat with the air and condenses, and liquid refrigerant flows out from the second opening 35a of the second header 35 to the refrigerant outlet pipe 42. In a configuration where at least one of the pair of headers is separated by a partition 43 and the refrigerant is reversed at the intermediate header 36, the refrigerant tends to become liquid in the region downstream of the intermediate header 36, which is the turning point of the refrigerant flow path. On the other hand, in the region upstream of the intermediate header 36, the refrigerant tends to become a gas-liquid two-phase refrigerant, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. Therefore, by placing the first temperature sensor 61 in a part of the first heat exchanger 37A, which is the upstream region, the gas-liquid two-phase region is widened, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. As a result, the degree of subcooling can be determined more accurately under a wide range of refrigerant flow rate conditions. In configurations where multiple partitions 43 are provided in a pair of headers, it is preferable to place the first temperature sensor 61 in the most upstream region.

[0067] Figure 10 is a schematic front view showing a modified example of the condenser 30 according to Embodiment 3. While the first temperature sensor 61 is described above as being located in a part of the first heat exchanger 37A, which is the upstream region, it is not limited to this configuration. The region within the intermediate header 36 also becomes more susceptible to becoming a gas-liquid two-phase refrigerant, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. Therefore, as shown in Figure 10, the sensor may also be located in the intermediate header 36. By providing the first temperature sensor 61 in the intermediate header 36 in this way, it is possible to suppress the deterioration of heat exchanger performance due to airflow obstruction and heat transfer inhibition caused by the sensor.

[0068] In the refrigeration cycle device 100 according to Embodiment 3, a first header 34 and a second header 35 are arranged at one of the upper and lower ends of the flattened tube group 31, an intermediate header 36 is arranged at the other of the upper and lower ends of the flattened tube group 31, and a partition 43 for reversing the flow path is provided between the first header 34 and the second header 35.

[0069] Furthermore, in the refrigeration cycle device 100 according to Embodiment 3, the first temperature sensor 61 is provided in the group of flattened tubes 31 connected to the first header 34.

[0070] According to the refrigeration cycle device 100 of Embodiment 3, by providing the first temperature sensor 61 in a part of the first heat exchanger 37A, which is the upstream region, the gas-liquid two-phase region is widened, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. As a result, the degree of subcooling can be determined more accurately under a wide range of refrigerant flow rate conditions.

[0071] Furthermore, in the refrigeration cycle device 100 according to Embodiment 3, the first temperature sensor 61 is provided in the intermediate header 36.

[0072] According to the refrigeration cycle device 100 of Embodiment 3, by providing the first temperature sensor 61 in the intermediate header 36, the gas-liquid two-phase region is widened, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant, thus enabling more accurate determination of the degree of subcooling under a wide range of refrigerant flow rate conditions. Furthermore, by providing the first temperature sensor 61 in the intermediate header 36, it is possible to suppress the deterioration of heat exchanger performance due to airflow blockage and heat transfer inhibition caused by the sensor.

[0073] Embodiment 4. Embodiment 4 will be described below, but the description of parts that overlap with Embodiments 1 to 3 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 to 3.

[0074] Figure 11 is a schematic side view showing the condenser 30 according to Embodiment 4. Figure 12 is an enlarged cross-sectional side perspective view of the upper part of the condenser 30 according to Embodiment 4. In Figures 11 and 12, the black arrows indicate the refrigerant flow, and the white arrows in Figure 11 indicate the air flow direction.

[0075] As shown in Figures 11 and 12, the condenser 30 according to Embodiment 4 consists of a plurality of flat tubes 38 (38A, 38B) arranged vertically in the vertical direction and spaced apart in a direction perpendicular to the airflow direction, a plurality (two in Embodiment 4) of groups of flat tubes 31 (31A, 31B) spaced apart in the airflow direction, corrugated fins 39 (39A, 39B) placed between each adjacent flat tube 38 (38A, 38B) in each of the groups of flat tubes 31 (31A, 31B), and a pair of headers placed above and below each of the groups of flat tubes 31 (31A, 31B). The corrugated fins 39A and 39B are not shown. The pair of headers consists of a first header 34 (34A, 34B) and a row-pass header 70. The upper ends of the upwind flattened pipe group 31A and the downwind flattened pipe group 31B are inserted into the row-pass header 70. The lower end of the upwind flattened pipe group 31A is inserted into the upwind first header 34A, and the lower end of the downwind flattened pipe group 31B is inserted into the downwind first header 34B. A first opening 34Aa, which is a refrigerant inlet, is formed at one end of the upwind first header 34A, and a refrigerant inlet pipe 41 is connected to the first opening 34Aa. A second opening 34Ba, which is a refrigerant outlet, is formed at one end of the downwind first header 34B, and a refrigerant outlet pipe 42 is connected to the second opening 34Ba.

[0076] Gaseous refrigerant flows in from the first opening 34Aa of the first header 34A on the upwind side, and flows in the order of the first header 34A on the upwind side, the group of flattened tubes 31A on the upwind side, the row header 70, the group of flattened tubes 31B on the downwind side, and the first header 34B on the downwind side, and liquid refrigerant flows out from the second opening 34Ba of the first header 34B on the downwind side.

[0077] As shown in Figures 11 and 12, the condenser 30 is equipped with a first temperature sensor 61 and a second temperature sensor 62 for detecting the refrigerant temperature. The first temperature sensor 61 and the second temperature sensor 62 are, for example, thermistors. The second temperature sensor 62 is also provided in the refrigerant outlet pipe 42. The second temperature sensor 62 may be provided in the first header 34B on the leeward side, or in the refrigerant piping connected to the refrigerant outlet pipe 42. The first temperature sensor 61 detects the refrigerant temperature in the refrigerant flow path between the first header 34 and the second header 35, and detects the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. The second temperature sensor 62 detects the refrigerant temperature in the refrigerant flow path inside the first header 34B on the leeward side, the refrigerant outlet pipe 42, or the refrigerant piping connected to the refrigerant outlet pipe 42, and detects the temperature of the liquid refrigerant. Therefore, the degree of subcooling can be determined from the difference between the temperature detected by the second temperature sensor 62 and the temperature detected by the first temperature sensor 61.

[0078] Here, gaseous refrigerant flows from the refrigerant inlet pipe 41 to the first opening 34a of the first header 34A on the upwind side, and as it flows in the order of the first header 34A on the upwind side, the flattened pipe group 31A on the upwind side, the column header 70, the flattened pipe group 31B on the downwind side, and the first header 34B on the downwind side, the refrigerant exchanges heat with the air and condenses, and liquid refrigerant flows out of the second opening 34Ba of the first header 34B on the downwind side to the refrigerant outlet pipe 42. In a configuration in which the refrigerant is reversed at the column header 70, the refrigerant tends to become a gas-liquid two-phase refrigerant at the column header 70, which is the turning point of the refrigerant flow path, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. Therefore, by providing the first temperature sensor 61 at the column header 70, the gas-liquid two-phase region is wide, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant, and thus the degree of subcooling can be determined more accurately under a wide range of refrigerant flow rate conditions. Furthermore, by providing the first temperature sensor 61 in the column header 70, it is possible to suppress the deterioration of heat exchanger performance due to airflow blockage and heat transfer inhibition caused by the sensor. In a configuration in which three or more groups of flattened tubes 31 are arranged at intervals in the airflow direction and multiple column headers 70 are provided, it is preferable to provide the first temperature sensor 61 in the upstreammost column header 70.

[0079] In the refrigeration cycle device 100 according to Embodiment 4, the condenser 30 has a plurality of flattened tube groups 31 arranged at intervals in the air flow direction, a first header 34 and a second header 35 are arranged at one of the upper and lower ends of the plurality of flattened tube groups 31, and a column-passing header 70 is arranged at the other of the upper and lower ends of the plurality of flattened tube groups 31, and the first temperature sensor 61 is provided on the column-passing header 70.

[0080] According to the refrigeration cycle device 100 of Embodiment 4, by providing the first temperature sensor 61 in the column header 70, the gas-liquid two-phase region is widened, making it easier to detect the temperature (saturation temperature) of the gas-liquid two-phase refrigerant, thus enabling more accurate determination of the degree of subcooling under a wide range of refrigerant flow rate conditions. Furthermore, by providing the first temperature sensor 61 in the column header 70, it is possible to suppress the deterioration of heat exchanger performance due to airflow blockage and heat transfer inhibition caused by the sensor.

[0081] Embodiment 5. Embodiment 5 will be described below, but the description of parts that overlap with Embodiments 1 to 4 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 to 4.

[0082] Figure 13 is a schematic diagram illustrating the installation position of the third temperature sensor 63 of the condenser 30 according to Embodiment 5. The black arrows in Figure 13 indicate the refrigerant flow.

[0083] The condenser 30 according to Embodiment 5 has the same configuration as the condenser 30 according to Embodiment 1 shown in Figure 4, except that it is equipped with a third temperature sensor 63. As shown in Figure 13, the condenser 30 is provided with a first temperature sensor 61, a second temperature sensor 62, and a third temperature sensor 63 for detecting the refrigerant temperature. The first temperature sensor 61, the second temperature sensor 62, and the third temperature sensor 63 are, for example, thermistors. Furthermore, if the position closest to the first opening 34a, which is the refrigerant inlet, in the horizontal direction of the heat exchanger 37 is defined as 0%, and the position furthest from the first opening 34a is defined as 100%, the first temperature sensor 61 is provided at a position between 0% and 50% in the horizontal direction of the heat exchanger 37. The second temperature sensor 62 is provided in the refrigerant outlet pipe 42. The second temperature sensor 62 may be provided in the second header 35, or in the refrigerant piping connected to the refrigerant outlet pipe 42. The first temperature sensor 61 detects the refrigerant temperature in the refrigerant flow path between the first header 34 and the second header 35, and detects the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. The second temperature sensor 62 detects the refrigerant temperature in the refrigerant flow path inside the second header 35, the refrigerant outlet pipe 42, or the refrigerant piping connected to the refrigerant outlet pipe 42, and detects the temperature of the liquid refrigerant. Therefore, the degree of subcooling can be determined from the difference between the temperature detected by the second temperature sensor 62 and the temperature detected by the first temperature sensor 61.

[0084] Furthermore, if the position closest to the first opening 34a, which is the refrigerant inlet, in the horizontal direction of the heat exchanger 37 is defined as 0%, and the position furthest from the first opening 34a is defined as 100%, then the third temperature sensor 63 is positioned at the 50-100% horizontal position of the heat exchanger 37. The third temperature sensor 63 detects the refrigerant temperature in the refrigerant flow path between the first header 34 and the second header 35, and detects the temperature (saturation temperature) of the gas-liquid two-phase refrigerant. In this way, the first temperature sensor 61 is provided on the shortest flow path side, where the refrigerant flow path of the condenser 30 is shortest, and the third temperature sensor 63 is provided on the longest flow path side, where the refrigerant flow path of the condenser 30 is longest. By comparing the detected temperatures, it is possible to determine whether the refrigerant flow balance is disrupted depending on the position of the refrigerant flow path.

[0085] As described above, the refrigeration cycle device 100 according to Embodiment 5 is equipped with a third temperature sensor 63 located at a position between 50% and 100% in the horizontal direction of the heat exchanger 37.

[0086] According to the refrigeration cycle device 100 of Embodiment 5, a first temperature sensor 61 is provided on the shortest path side, where the refrigerant flow path of the condenser 30 is shortest, and a third temperature sensor 63 is provided on the longest path side, where the refrigerant flow path of the condenser 30 is longest. By comparing the detected temperatures of these sensors, it is possible to determine whether the refrigerant flow balance is disrupted depending on the position of the refrigerant flow path.

[0087] Embodiment 6. Embodiment 6 will be described below, but the description of parts that overlap with Embodiments 1 to 5 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 to 5.

[0088] Figure 14 is a refrigerant circuit diagram showing a refrigeration cycle device 100 according to Embodiment 6. The black arrows in Figure 14 indicate the flow of refrigerant.

[0089] As shown in Figure 14, the refrigeration cycle device 100 according to Embodiment 6 includes a compressor 11, a plurality of condensers 30 (30A, 30B), a first fan 12, a throttle device 13, an evaporator 14, a second fan 15, a flow control valve 16, and a control device 50.

[0090] Furthermore, the refrigeration cycle device 100 includes a compressor 11, a plurality of condensers 30, a flow control valve 16, a throttle device 13, and an evaporator 14, all connected by refrigerant piping, and comprises a refrigerant circuit 101 through which the refrigerant circulates. It is also possible to provide a flow path switching device, such as a four-way valve, in the refrigeration cycle device 100, and configure it so that both cooling and heating operations can be performed by switching the flow path switching device.

[0091] The refrigerant circulating in the refrigerant circuit 101 is a single refrigerant from among R1234yf, R1234ze, and R290, or a mixture of two or more of these, or a mixture of one of these with another refrigerant, or a mixture containing R1132(E), or a mixture containing R1123. By using the above refrigerants, the low boiling point refrigerants have a low vapor density and a high flow velocity, which increases the effect of inertial force, thus greatly improving the refrigerant distribution performance. In addition, with mixed refrigerants, concentration variations occur as the distribution deteriorates, so the effect of performance improvement through improved refrigerant distribution performance can be greatly increased.

[0092] The compressor 11 draws in a low-temperature, low-pressure refrigerant, compresses the drawn-in refrigerant, and discharges a high-temperature, high-pressure refrigerant. The compressor 11 is, for example, an inverter compressor whose capacity, which is the amount of refrigerant delivered per unit time, is controlled by changing the operating frequency.

[0093] The multiple condensers 30 perform heat exchange between the air and the refrigerant. The multiple condensers 30 release the heat from the refrigerant into the air, causing it to condense. The multiple condensers 30 are connected in parallel to each other. In Embodiment 6, two sets of multiple condensers 30 are provided.

[0094] The first fan 12 supplies air to the multiple condensers 30, and the amount of air supplied to the multiple condensers 30 is adjusted by controlling its rotation speed.

[0095] The throttling device 13 is, for example, an electronic expansion valve that can adjust the throttling opening, and by adjusting the opening, it controls the pressure of the refrigerant flowing into the evaporator 14.

[0096] The evaporator 14 performs heat exchange between the air and the refrigerant. The evaporator 14 evaporates the refrigerant, and the heat of vaporization used in the process cools the air.

[0097] The second fan 15 supplies air to the evaporator 14, and the amount of air supplied to the evaporator 14 is adjusted by controlling its rotation speed.

[0098] The flow control valve 16 is, for example, an electronic expansion valve that can adjust the opening of a throttle, and controls the amount of refrigerant flowing into each condenser 30 by adjusting the opening. There are one flow control valve 16, which is the number of condensers 30 minus one. Therefore, in embodiment 6, since there are two condensers 30, there is one flow control valve 16.

[0099] The control device 50 consists of, for example, a CPU (also known as a Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, or processor) that executes a program stored in dedicated hardware or a memory unit (not shown).

[0100] If the control device 50 is dedicated hardware, it may be, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Each of the functional units realized by the control device 50 may be realized by individual hardware, or each functional unit may be realized by a single piece of hardware.

[0101] When the control device 50 is a CPU, each function performed by the control device 50 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory unit. The CPU realizes each function of the control device 50 by reading and executing the programs stored in the memory unit. Here, the memory unit stores various types of information and includes, for example, non-volatile semiconductor memory with rewritable data, such as flash memory, EPROM, and EEPROM.

[0102] Furthermore, some of the functions of the control device 50 may be implemented using dedicated hardware, while other functions may be implemented using software or firmware.

[0103] The control device 50 controls the compressor 11 and the throttle device 13, etc., based on detection signals from various sensors (not shown) provided in the refrigeration cycle device 100, and operation signals from an operation unit (not shown), thereby controlling the operation of the entire refrigeration cycle device 100.

[0104] One of the multiple condensers 30 is equipped with a first temperature sensor 61 for detecting the refrigerant temperature. Each of the multiple condensers 30 is also equipped with a second temperature sensor 62. The first temperature sensor 61 and the second temperature sensor 62 are, for example, thermistors. The first temperature sensor 61 detects the temperature (saturation temperature) of the two-phase gaseous refrigerant. The second temperature sensor 62 detects the temperature of the liquid refrigerant. Therefore, the degree of subcooling can be determined from the difference between the temperature detected by the second temperature sensor 62 and the temperature detected by the first temperature sensor 61.

[0105] The control device 50 determines the degree of subcooling of each condenser 30 based on the difference between the temperature detected by each second temperature sensor 62 and the temperature detected by one first temperature sensor 61, and controls the opening degree of each flow control valve 16 according to that value.

[0106] By configuring the refrigeration cycle device 100 in this way, it is not necessary to provide a first temperature sensor 61 in each of the multiple condensers 30, thus reducing the number of first temperature sensors 61. Furthermore, by controlling the opening degree of each flow control valve 16 as described above, the refrigerant flow rate ratio to each condenser 30 can be controlled in accordance with the heat load distribution, thereby improving the heat exchanger performance.

[0107] As described above, the refrigeration cycle device 100 according to Embodiment 6 includes a fan that supplies air to the condenser 30, and a control device 50 that controls at least one of the following: the rotation frequency of the compressor 11, the opening degree of the throttle device 13, and the rotation speed of the fan, based on the degree of subcooling determined based on the difference between the temperature detected by the second temperature sensor 62 and the temperature detected by the first temperature sensor 61.

[0108] Furthermore, the refrigeration cycle device 100 according to Embodiment 6 comprises a plurality of condensers 30 connected in parallel to each other, and a flow control valve 16 that controls the amount of refrigerant flowing into each condenser 30. A first temperature sensor 61 is provided in at least one of the plurality of condensers 30, and a second temperature sensor 62 is provided in each of the plurality of condensers 30. The control device 50 determines the degree of subcooling of each condenser 30 based on the difference between the temperature detected by each second temperature sensor 62 and the temperature detected by the first temperature sensor 61, and controls the opening degree of the flow control valve 16 based on the degree of subcooling of each condenser 30.

[0109] According to the refrigeration cycle device 100 of Embodiment 6, it is not necessary to provide a first temperature sensor 61 in each of the multiple condensers 30, thus reducing the number of first temperature sensors 61. Furthermore, by controlling the opening degree of each flow control valve 16 as described above, the refrigerant flow rate ratio to each condenser 30 can be controlled in accordance with the heat load distribution, thereby improving the heat exchanger performance.

[0110] 11 Compressor, 12 First fan, 13 Throttle device, 14 Evaporator, 15 Second fan, 16 Flow control valve, 30 Condenser, 30A Condenser, 30B Condenser, 31 Flat tube group, 31A Flat tube group, 31B Flat tube group, 34 First header, 34A First header, 34Aa First opening, 34B First header, 34Ba Second opening, 34a First opening, 35 Second header, 35a Second opening, 36 Intermediate header, 37 Heat exchanger, 37A First heat exchanger, 37B Second heat exchanger, 38 Flat tube, 38A Flat tube, 38B Flat tube, 39 Corrugated fin, 39A Corrugated fin, 39B Corrugated fin, 41 Refrigerant inlet pipe, 42 Refrigerant outlet pipe, 43 Partition, 50 Control device, 61 1st temperature sensor, 62; 2nd temperature sensor, 63; 3rd temperature sensor, 70; column header, 100; refrigeration cycle device, 101; refrigerant circuit.

Claims

1. A refrigeration cycle device comprising a compressor, a condenser, a throttle device, and an evaporator connected by refrigerant piping, and a refrigerant circuit through which a refrigerant circulates, wherein the condenser consists of a plurality of flat tubes arranged vertically in the vertical direction and spaced apart in a direction perpendicular to the airflow direction, and a heat exchanger composed of a group of flat tubes spaced apart in the airflow direction and corrugated fins arranged between each adjacent flat tube, a first header located at the upper or lower end of the group of flat tubes and having a refrigerant inlet formed thereon, a second header located at the upper or lower end of the group of flat tubes and having a refrigerant outlet formed thereon, a first temperature sensor located at a position away from the first and second headers for detecting the refrigerant temperature in the refrigerant flow path between the first and second headers, and a second temperature sensor located in a refrigerant outlet pipe connected to the second header or the refrigerant outlet.

2. The refrigeration cycle apparatus according to claim 1, wherein, when the upper end of the heat exchanger is defined as 0% and the lower end as 100%, the first temperature sensor is provided at a position between 30% and 70% in the vertical direction of the heat exchanger.

3. The refrigeration cycle apparatus according to claim 1 or 2, wherein, when the position closest to the refrigerant inlet in the horizontal direction of the heat exchanger is defined as 0%, and the position furthest from the refrigerant inlet is defined as 100%, the first temperature sensor is provided at a position between 0% and 50% in the horizontal direction of the heat exchanger.

4. The refrigeration cycle apparatus according to claim 3, wherein the first temperature sensor is provided on the flat tube located in the group of flat tubes that is closest to the refrigerant inlet.

5. The refrigeration cycle apparatus according to claim 3 or 4, further comprising a third temperature sensor provided at a position between 50% and 100% in the horizontal direction of the heat exchanger.

6. The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the first temperature sensor is supported by the corrugated fin.

7. The refrigeration cycle apparatus according to claim 1, wherein the first header and the second header are arranged at one of the upper and lower ends of the flattened tube group, an intermediate header is arranged at the other of the upper and lower ends of the flattened tube group, and a partition for reversing the flow path is provided between the first header and the second header.

8. The refrigeration cycle apparatus according to claim 7, wherein the first temperature sensor is provided in the intermediate header.

9. The refrigeration cycle apparatus according to claim 7, wherein the first temperature sensor is provided in the group of flat tubes connected to the first header.

10. The refrigeration cycle apparatus according to claim 1, wherein the condenser has a plurality of groups of flattened tubes arranged at intervals in the direction of air flow, the first header and the second header are located at one of the upper and lower ends of the plurality of groups of flattened tubes, a column header is located at the other of the upper and lower ends of the plurality of groups of flattened tubes, and the first temperature sensor is provided on the column header.

11. A refrigeration cycle apparatus according to any one of claims 1 to 10, comprising: a fan that supplies air to the condenser; and a control device that controls at least one of the following: the rotational frequency of the compressor, the opening of the throttle device, and the rotational speed of the fan, based on the degree of subcooling determined based on the difference between the temperature detected by the second temperature sensor and the temperature detected by the first temperature sensor.

12. The refrigeration cycle apparatus according to claim 11, comprising: a plurality of condensers connected in parallel to each other; and a flow control valve for controlling the amount of refrigerant flowing into each of the condensers, wherein at least one of the plurality of condensers is provided with the first temperature sensor, and each of the plurality of condensers is provided with the second temperature sensor, and the control device determines the degree of subcooling of each condenser based on the difference between the temperature detected by each of the second temperature sensors and the temperature detected by the first temperature sensor, and controls the opening degree of the flow control valve based on the degree of subcooling of each condenser.

13. A refrigeration cycle apparatus according to any one of claims 1 to 12, in which a single refrigerant of any one of R1234yf, R1234ze, and R290, or a mixture of two or more of these, or a mixture of any one of these and another refrigerant, a mixture containing R1132(E), or a mixture containing R1123 is used.

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