Refrigeration cycle apparatus

Abstract

This refrigeration cycle apparatus comprises a refrigerant circuit in which a compressor, a condenser, a throttle device, and an evaporator are connected by refrigerant piping, and in which a refrigerant circulates. The condenser comprises: a heat exchange body which is composed of flat tube groups that comprise a plurality of flat tubes each disposed upright in a vertical orientation and arranged side by side at intervals in a direction orthogonal to the air flow direction and that are disposed at an interval in the air flow direction, and corrugated fins each disposed between two of the plurality of flat tubes; a pair of headers disposed above and below the flat tube groups; and a first temperature sensor provided to the heat exchange body. The pair of headers have formed therein a refrigerant inflow port and a refrigerant outflow port. When the position closest to the refrigerant inflow port in the horizontal direction of the heat exchange body is defined as 0% and the position farthest from the refrigerant inflow port is defined as 100%, the first temperature sensor is provided at a position of 50-100% in the horizontal direction of the heat exchange body.

Description

Refrigeration cycle device 【0001】 The present disclosure relates to a refrigeration cycle device. 【0002】 Conventionally, there has been a refrigeration cycle device including a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger connected by refrigerant pipes, and having a refrigerant circuit in which refrigerant circulates (see, for example, Patent Document 1). 【0003】 In such a refrigeration cycle device, when performing a cooling operation, by accurately detecting 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 includes a plurality of flat tubes arranged vertically and parallel to each other with a space in a direction orthogonal to the air flow direction, and a pair of headers arranged above and below the plurality of flat tubes. In such an outdoor heat exchanger, liquid retention occurs under specific conditions, and when liquid retention occurs, the performance of the heat exchanger deteriorates. Therefore, detecting the presence or absence of liquid retention is important for suppressing a decrease in the performance of the heat exchanger. 【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 detecting the presence or absence of a retention region in a condenser. 【0007】The refrigeration cycle device according to this disclosure is 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 the 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 air flow direction, and a heat exchange body composed of a group of flat tubes spaced apart in the air flow direction and corrugated fins arranged between the plurality of flat tubes, a pair of headers arranged above and below the group of flat tubes, and the first temperature sensor provided on the heat exchange body, wherein the pair of headers have a refrigerant inlet and a refrigerant outlet, and the first temperature sensor is provided at a position between 50% and 100% in the horizontal direction of the heat exchange body, with the position closest to the refrigerant inlet being 0% and the position furthest from the refrigerant inlet being 100%. 【0008】 Furthermore, the refrigeration cycle device according to the present disclosure is 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 the 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 air flow direction, and a heat exchange body composed of a group of flat tubes spaced apart in the air flow direction and corrugated fins arranged between the plurality of flat tubes, a pair of headers arranged above and below the group of flat tubes, and the first temperature sensor provided on the heat exchange body, wherein at least one of the pair of headers is partitioned internally by a partition for reversing the flow path, the pair of headers has a refrigerant inlet and a refrigerant outlet, the heat exchange body has at least one upward flow region, and the first temperature sensor is provided in each of the at least one upward flow region. 【0009】 According to the refrigeration cycle device described herein, it is possible to detect whether or not a condensation area is occurring in the condenser. 【0010】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 schematic front view showing a condenser according to Embodiment 2. This is a schematic front view showing a condenser according to Embodiment 3. This is a schematic side view showing a condenser according to Embodiment 4. This is a schematic cross-sectional side perspective view of the upper part of the condenser according to Embodiment 4. 【0011】 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 terms 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 condenser from the front. 【0012】 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. 【0013】 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. 【0014】 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. 【0015】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. 【0016】 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. 【0017】 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. 【0018】 The condenser 30 performs heat exchange between the air and the refrigerant. The condenser 30 functions as a condenser that releases heat from the refrigerant into the air, thereby condensing the refrigerant. 【0019】 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. 【0020】 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. 【0021】 The evaporator 14 performs heat exchange between the air and the refrigerant. The evaporator 14 functions as an evaporator that evaporates the refrigerant and cools the air with the heat of vaporization that occurs during the process. 【0022】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. 【0023】 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). 【0024】 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. 【0025】 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. 【0026】 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. 【0027】 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. 【0028】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. 【0029】 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 the plurality of flat tubes 38. 【0030】 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 outlet, is formed at one end of the first header 34, and a refrigerant outflow pipe 42 is connected to the first opening 34a. A second opening 35a, which is a refrigerant inlet, is formed at one end of the second header 35, and a refrigerant inflow pipe 41 is connected to the second opening 35a. Gaseous refrigerant flows in from the second opening 35a of the second header 35, flows through the second header 35, the flattened tube group 31, and the first header 34 in that order, and liquid refrigerant flows out from the first opening 34a of the first header 34. 【0031】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 first header 34 or in the refrigerant piping connected to the refrigerant outlet pipe 42. The first temperature sensor 61 detects the temperature (saturation temperature) of the gas-liquid two-phase 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. 【0032】Here, gaseous refrigerant flows from the refrigerant inlet pipe 41 to the second opening 35a of the second header 35, and as it flows through the second header 35, the flattened tube group 31, and the first header 34, the refrigerant exchanges heat with the air and condenses, and liquid refrigerant flows out from the first opening 34a of the first header 34 to the refrigerant outlet pipe 42. The shortest refrigerant flow path of the condenser 30 is in the order of P0, P1, P2, P3 as shown in Figure 4, and the longest refrigerant flow path of the condenser 30 is in the order of P0, P1, P4, P5, P2, P3 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 second opening 35a of the second header 35 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 second opening 35a, which is the refrigerant inlet. As a result, the refrigerant flow velocity is lower on the side farther from the second opening 35a. When the refrigerant flow velocity is low in the region where the refrigerant is flowing upward, a stagnation area occurs where the liquid refrigerant cannot rise due to the effect of gravity. Therefore, the refrigerant flow is more likely to stagnate on the side farther from the second opening 35a, making it easier to detect liquid stagnation. Thus, as shown in Figure 4, if the position closest to the second opening 35a in the horizontal direction of the heat exchanger 37 is set to 0%, and the position furthest from the second opening 35a is set to 100%, then by placing at least a part of the first temperature sensor 61 at a position between 50% and 100% in the horizontal direction of the heat exchanger 37, it is possible to detect whether or not liquid stagnation is occurring. Note that the first temperature sensor 61 may be placed at any position in the vertical direction of the heat exchanger 37. In this case, if liquid stagnation occurs, the refrigerant temperature will be higher than when liquid stagnation does not occur, and the temperature of the refrigerant flowing through the refrigerant channel will fall outside the predetermined temperature range. Therefore, the presence or absence of liquid stagnation can be detected by whether or not the temperature detected by the first temperature sensor 61 is within the predetermined temperature range. The first temperature sensor 61 may be installed on the flat pipe 38 or on the corrugated fin 39, but by installing the first temperature sensor 61 so as to be supported by the corrugated fin 39, it is possible to install the first temperature sensor 61 more easily. 【0033】Furthermore, the refrigerant flow velocity is lowest in the longest refrigerant flow path of the condenser 30 (in the order of P0, P1, P4, P5, P2, and P3 shown in Figure 4), making liquid stagnation most likely to occur. The flat tube 38 located furthest from the second opening 35a among the flat tube group 31 constitutes the longest refrigerant flow path of the condenser 30. Therefore, by installing the first temperature sensor 61 on the flat tube 38 located furthest from the second opening 35a among the flat tube group 31, the presence or absence of liquid stagnation can be detected more accurately. 【0034】 As described above, the refrigeration cycle device 100 according to Embodiment 1 is a refrigeration cycle device 100 that includes 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. 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 exchange body 37 composed of a group of flat tubes 31 spaced apart in the air flow direction and corrugated fins 39 arranged between the plurality of flat tubes 38. The condenser 30 also includes a pair of headers arranged above and below the group of flat tubes 31, and a first temperature sensor 61 provided on the heat exchange body 37. The pair of headers have a refrigerant inlet and a refrigerant outlet. When the position closest to the refrigerant inlet in the horizontal direction of the heat exchange body 37 is defined as 0%, and the position furthest from the refrigerant inlet is defined as 100%, the first temperature sensor 61 is provided at a position between 50% and 100% in the horizontal direction of the heat exchange body 37. 【0035】 In the refrigeration cycle device 100 according to Embodiment 1, the first temperature sensor 61 is provided at a position 50-100% horizontally of the heat exchanger 37, which is far from the refrigerant inlet where liquid stagnation is likely to occur, so it is possible to detect whether or not liquid stagnation is occurring. 【0036】 Furthermore, in the refrigeration cycle device 100 according to Embodiment 1, the first temperature sensor 61 is provided on the flat tube 38 located at the position furthest from the refrigerant inlet among the group of flat tubes 31. 【0037】According to the refrigeration cycle device 100 according to Embodiment 1, since the first temperature sensor 61 is provided in the flat tube 38 which is located at the position farthest from the refrigerant inlet among the flat tube groups 31 where liquid retention is most likely to occur, the presence or absence of liquid retention can be detected more accurately. 【0038】 Moreover, in the refrigeration cycle device 100 according to Embodiment 1, the first temperature sensor 61 is supported by the corrugated fin 39. 【0039】 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. 【0040】 Moreover, in the refrigeration cycle device 100 according to Embodiment 1, a second temperature sensor 62 is provided in the header in which the refrigerant outlet is formed or in the refrigerant outflow pipe 42 connected to the refrigerant outlet. 【0041】 According to the refrigeration cycle device 100 according to Embodiment 1, the degree of subcooling can be obtained from the difference between the detected temperature of the second temperature sensor 62 and the detected temperature of the first temperature sensor 61. 【0042】 Embodiment 2. Hereinafter, Embodiment 2 will be described. For the parts that overlap with Embodiment 1, the description will be omitted, and the same reference numerals will be given to the same parts or corresponding parts as in Embodiment 1. 【0043】 FIG. 5 is a front view schematically showing the condenser 30 according to Embodiment 2. The black arrows in FIG. 5 indicate the refrigerant flow. 【0044】 As shown in FIG. 5, the condenser 30 according to Embodiment 2 includes a heat exchanger 37 composed of a flat tube group 31 formed by a plurality of flat tubes 38 arranged vertically and side by side at intervals in a horizontal direction perpendicular to the air flow direction, and corrugated fins 39 arranged between the plurality of flat tubes 38. 【0045】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 the multiple flat tubes 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 the multiple flat tubes 38 will be referred to as the second heat exchanger 37B. 【0046】 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. 【0047】 As shown in Figure 5, 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 temperature (saturation temperature) of the gas-liquid two-phase 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. 【0048】 Here, gaseous refrigerant flows into the first opening 34a of the first header 34 from the refrigerant inlet pipe 41, and the refrigerant exchanges heat with air and condenses in the process of flowing in the order of the first header 34, the first flat tube group, the intermediate header 36, the second flat tube group, and the second header 35, 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 partitioned by a partition 43 and the refrigerant is turned back by the intermediate header 36, in the upward flow region, when the flow velocity of the refrigerant becomes low, the liquid refrigerant cannot rise due to the influence of gravity and liquid retention occurs. Therefore, it becomes easier to detect liquid retention in the upward flow region where the flow of the refrigerant is likely to stagnate. Thus, by providing the first temperature sensor 61 in a part of the second heat exchanger 37B that is the upward flow region, it is possible to detect the presence or absence of liquid retention. Here, when liquid retention occurs, the refrigerant temperature becomes higher than when liquid retention does not occur, and since the refrigerant temperature flowing through the refrigerant flow path deviates from a predetermined temperature range, it is possible to detect the presence or absence of liquid retention based on whether the detected temperature of the first temperature sensor 61 is within the predetermined temperature range. In a configuration where a plurality of partitions 43 are provided in the pair of headers and a plurality of upward flow regions are formed in one heat exchanger 37, by providing the first temperature sensor 61 in a part of each of the plurality of upward flow regions, it is possible to detect liquid retention wherever it occurs in the plurality of upward flow regions. 【0049】The refrigeration cycle device 100 according to Embodiment 2 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. 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 37 composed of a group of flat tubes 31 spaced apart in the air flow direction and corrugated fins 39 arranged between the plurality of flat tubes 38. The condenser 30 comprises a pair of headers arranged above and below the group of flat tubes 31, and a first temperature sensor 61 provided on the heat exchanger 37. At least one of the pair of headers is partitioned internally by a partition 43 for reversing the flow path, and the pair of headers have a refrigerant inlet and a refrigerant outlet. The heat exchanger 37 has at least one upward flow region, and the first temperature sensor 61 is provided in each of the at least one upward flow region. 【0050】 According to the refrigeration cycle device 100 of Embodiment 2, since the first temperature sensor 61 is provided in the upward flow region where liquid stagnation is likely to occur, it is possible to detect whether or not liquid stagnation is occurring. 【0051】 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. 【0052】 Figure 6 is a schematic front view showing the condenser 30 according to Embodiment 3. The black arrows in Figure 6 indicate the refrigerant flow. 【0053】 As shown in Figure 6, 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 the plurality of flat tubes 38. 【0054】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 the multiple flat tubes 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 the multiple flat tubes 38 will be referred to as the second heat exchanger 37B. 【0055】 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. 【0056】As shown in Figure 6, 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 temperature (saturation temperature) of the gas-liquid two-phase 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. 【0057】 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 folded back at the intermediate header 36, if the flow velocity of the refrigerant decreases in the upward flow region, the liquid refrigerant cannot rise due to the effect of gravity, causing liquid stagnation. Therefore, it is easier to detect liquid stagnation in the upward flow region where the refrigerant flow tends to stagnate. To this end, by providing the first temperature sensor 61 on a part of the first heat exchanger 37A before it is folded back at the intermediate header 36, which is the upward flow region, it is possible to detect whether or not liquid stagnation is occurring. In this case, if liquid stagnation occurs, the refrigerant temperature becomes higher than when liquid stagnation does not occur, and the temperature of the refrigerant flowing through the refrigerant channel falls outside the predetermined temperature range. Therefore, the presence or absence of liquid stagnation can be detected by whether or not the temperature detected by the first temperature sensor 61 is within the predetermined temperature range. In a configuration in which multiple partitions 43 are provided in a pair of headers and multiple upward flow regions are formed in a single heat exchanger 37, by providing the first temperature sensor 61 in a part of each of the multiple upward flow regions, liquid stagnation can be detected no matter where it occurs in the multiple upward flow regions. 【0058】The refrigeration cycle device 100 according to Embodiment 3 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. 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 37 composed of a group of flat tubes 31 spaced apart in the air flow direction and corrugated fins 39 arranged between the plurality of flat tubes 38. The condenser 30 comprises a pair of headers arranged above and below the group of flat tubes 31, and a first temperature sensor 61 provided on the heat exchanger 37. At least one of the pair of headers is partitioned internally by a partition 43 for reversing the flow path, and the pair of headers have a refrigerant inlet and a refrigerant outlet. The heat exchanger 37 has at least one upward flow region, and the first temperature sensor 61 is provided in each of the at least one upward flow region. 【0059】 According to the refrigeration cycle device 100 of Embodiment 3, since the first temperature sensor 61 is provided in the upward flow region where liquid stagnation is likely to occur, it is possible to detect whether or not liquid stagnation is occurring. 【0060】 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. 【0061】 Figure 7 is a schematic side view showing the condenser 30 according to Embodiment 4. Figure 8 is an enlarged cross-sectional side perspective view of the upper part of the condenser 30 according to Embodiment 4. In Figures 7 and 8, the black arrows indicate the refrigerant flow, and the white arrows in Figure 7 indicate the air flow direction. 【0062】As shown in Figures 7 and 8, the condenser 30 according to Embodiment 4 consists of a plurality of flat tubes 38 (38A, 38B) arranged vertically in the upright 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) arranged between the plurality of flat tubes 38 (38A, 38B) of each of the groups of flat tubes 31 (31A, 31B), and a pair of headers arranged above and below each of the groups of flat tubes 31 (31A, 31B). The pair of headers consists of a first header 34 (34A, 34B) and a row-pass header 70. The upper end of the upwind group of flat tubes 31A and the upper end of the downwind group of flat tubes 31B are inserted into the row-pass header 70. Furthermore, the lower end of the flattened pipe group 31A on the upwind side is inserted into the first header 34A on the upwind side, and the lower end of the flattened pipe group 31B on the leeward side is inserted into the first header 34B on the leeward side. A first opening 34Aa, which is a refrigerant inlet, is formed at one end of the first header 34A on the upwind side, 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 first header 34B on the leeward side, and a refrigerant outlet pipe 42 is connected to the second opening 34Ba. 【0063】 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. 【0064】As shown in Figures 7 and 8, 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 downwind side, or in the refrigerant piping connected to the refrigerant outlet pipe 42. The first temperature sensor 61 detects the temperature (saturation temperature) of the gas-liquid two-phase 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. 【0065】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 group of flat pipes 31A on the upwind side, the row header 70, the group of flat pipes 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 folded back at the row header 70, if the flow velocity of the refrigerant decreases in the upward flow region, the liquid refrigerant cannot rise due to the effect of gravity, causing liquid stagnation. Therefore, it is easier to detect liquid stagnation in the upward flow region where the flow of refrigerant tends to stagnate. To this end, by installing the first temperature sensor 61 in a part of the first heat exchanger 37A on the upwind side, which is in the upward flow region, it is possible to detect whether or not liquid stagnation is occurring. In this case, if liquid stagnation occurs, the refrigerant temperature becomes higher than when liquid stagnation does not occur, and the temperature of the refrigerant flowing through the refrigerant path falls outside the predetermined temperature range. Therefore, the presence or absence of liquid stagnation can be detected by whether or not the temperature detected by the first temperature sensor 61 is within the predetermined temperature range. The column header 70 has multiple paths formed inside, each separated so that the refrigerant flowing through each path does not mix. Therefore, even if the first temperature sensor 61 is installed in the column header 70 instead of a part of the first heat exchanger 37A on the upwind side, which is the rising flow region, the presence or absence of liquid stagnation can be detected. In a configuration in which three or more groups of flattened tubes 31 are arranged at intervals in the air flow direction, and an upward flow region is formed in multiple heat exchangers 37, by installing the first temperature sensor 61 in a part of each of these multiple heat exchangers 37, liquid stagnation can be detected wherever it occurs in the multiple upward flow regions. 【0066】In the refrigeration cycle device 100 according to Embodiment 4, the condenser 30 has a plurality of flat tube groups 31 arranged at intervals in the air flow direction, a pair of headers are arranged above and below each of the plurality of flat tube groups 31, one of the pair of headers is composed of a common row-pass header 70 with the other pair of headers adjacent in the air flow direction, at least one of the plurality of heat exchangers 37 forms an upward flow region, and the first temperature sensor 61 is provided on each of the plurality of heat exchangers 37 in which the upward flow region is formed, or on each of the row-pass headers 70 connected to the plurality of heat exchangers 37 in which the upward flow region is formed. 【0067】 According to the refrigeration cycle device 100 of Embodiment 4, since the first temperature sensor 61 is provided in the upward flow region where liquid stagnation is likely to occur, it is possible to detect whether or not liquid stagnation is occurring. 【0068】 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. 【0069】 In Embodiment 5, the control device 50 is equipped with an AI learning function. The control device 50 estimates the amount of heat exchange based on the rotation frequency of the compressor 11 or the rotation speed of the first fan 12 that supplies air to the condenser 30, estimates the heat exchanger performance based on the change in the detected value of the first temperature sensor 61, and learns the relationship between them using AI. Based on what the AI ​​has learned, the control device 50 performs control that suppresses the occurrence of liquid stagnation and suppresses the reduction of the amount of heat exchange. For example, if the amount of heat exchange or the heat exchanger performance decreases, the frequency of the compressor 11 is increased, the rotation speed of the first fan 12 is increased, or the opening degree of the throttling device 13 is increased (opened). In other words, the control device 50 performs control that suppresses the occurrence of liquid stagnation and suppresses the reduction of the amount of heat exchange based on the rotation frequency of the compressor 11 or the rotation speed of the first fan 12 that supplies air to the condenser 30 and the detected value of the first temperature sensor 61. By performing such control, the occurrence of liquid stagnation can be suppressed and the reduction of the amount of heat exchange can be suppressed. 【0070】 As described above, the refrigeration cycle device 100 according to Embodiment 5 includes a fan that supplies air to the condenser 30, and a control device 50 that calculates an estimated value of the heat exchange amount based on the rotation frequency of the compressor 11 or the rotation speed of the fan, and performs control that suppresses the occurrence of liquid stagnation and control that suppresses the reduction of the heat exchange amount based on the value detected by the first temperature sensor 61 and the estimated value of the heat exchange amount. 【0071】 According to the refrigeration cycle device 100 of Embodiment 5, by performing the control described above, it is possible to suppress the occurrence of liquid stagnation and suppress the reduction in the amount of heat exchange. 【0072】 11 Compressor, 12 First fan, 13 Throttle device, 14 Evaporator, 15 Second fan, 30 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, 41 Refrigerant inlet pipe, 42 Refrigerant outlet pipe, 43 Partition, 50 Control device, 61 First temperature sensor, 62 Second temperature sensor, 70 Row-to-row 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 comprises a heat exchanger composed of a group of flat tubes arranged vertically and spaced apart in a direction perpendicular to the airflow direction, a group of flat tubes spaced apart in the airflow direction, and corrugated fins arranged between the group of flat tubes, a pair of headers arranged above and below the group of flat tubes, and a first temperature sensor provided on the heat exchanger, wherein the pair of headers have a refrigerant inlet and a refrigerant outlet, and the first temperature sensor is provided at a position between 50% and 100% in the horizontal direction of the heat exchanger, with the position closest to the refrigerant inlet being 0% and the position furthest from the refrigerant inlet being 100%.

2. The refrigeration cycle apparatus according to claim 1, wherein the first temperature sensor is provided on the flat tube located furthest from the refrigerant inlet among the group of flat tubes.

3. The refrigeration cycle apparatus according to claim 1, wherein the first temperature sensor is supported by the corrugated fin.

4. 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 comprises a heat exchanger composed of a group of flat tubes arranged vertically in the vertical direction and spaced apart in a direction perpendicular to the airflow direction, a group of flat tubes spaced apart in the airflow direction, and corrugated fins arranged between the group of flat tubes, a pair of headers arranged above and below the group of flat tubes, and a first temperature sensor provided on the heat exchanger, wherein at least one of the pair of headers is partitioned internally by a partition for reversing the flow path, the pair of headers has a refrigerant inlet and a refrigerant outlet, the heat exchanger has at least one upward flow region, and the first temperature sensor is provided in each of the at least one upward flow region.

5. The refrigeration cycle apparatus according to claim 1, wherein the condenser has a plurality of groups of flat tubes spaced apart in the airflow direction, the pair of headers are positioned above and below each of the plurality of groups of flat tubes, one of the pair of headers is a common row-pass header with the other of the pair of headers adjacent in the airflow direction, at least one of the plurality of heat exchangers forms an upward flow region, and the first temperature sensor is provided on each of the plurality of heat exchangers where the upward flow region is formed, or on each of the row-pass headers connected to the plurality of heat exchangers where the upward flow region is formed.

6. The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein a second temperature sensor is provided in the header on which the refrigerant outlet is formed or in the refrigerant outlet pipe connected to the refrigerant outlet.

7. A refrigeration cycle apparatus according to any one of claims 1 to 6, comprising: a fan that supplies air to the condenser; and a control device that determines an estimated value of the heat exchange amount based on the rotation frequency of the compressor or the rotation speed of the fan, and performs control that suppresses the occurrence of liquid stagnation and control that suppresses the reduction of the heat exchange amount based on the value detected by the first temperature sensor and the estimated value of the heat exchange amount.

8. A refrigeration cycle apparatus according to any one of claims 1 to 7, 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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