JP5889745B2 - Refrigeration cycle apparatus, and refrigeration apparatus and air conditioner equipped with the refrigeration cycle apparatus - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus, and a refrigeration apparatus and an air conditioner including the refrigeration cycle apparatus.

  Generally, in a chiller unit, a plurality of heat source side heat exchangers are arranged so as to surround a side surface. A machine room is disposed below the heat source side heat exchanger, and a fan for the heat source side heat exchanger is disposed above the heat source side heat exchanger. Therefore, the wind speed distribution of the heat source side heat exchanger becomes non-uniform in the vertical direction. As a result, the ratio of the flow rate of air passing through the heat source side heat exchanger and the flow rate of refrigerant becomes uneven, and the heat transfer area of the heat source side heat exchanger may not be used effectively.

  On the other hand, in Patent Document 1, a core is formed by arranging a plurality of heat transfer tubes connected in series in multiple stages so as to be orthogonal to a plurality of plate-like fins provided in parallel. Disclosed is a heat exchange unit arranged in a letter shape. In this heat exchange unit, the core is divided into three regions in the vertical direction, and each region is provided with a refrigerant distribution channel provided with a flow rate adjusting means by an orifice, and according to the air flow rate passing through each region. The refrigerant flow is distributed and the refrigerant is supplied to the heat transfer tubes.

  However, in recent years, APF (Annual Performance Factor), IPLV (Integrated Part Load Value), etc., which are period performance coefficients, are substituted for rated performance coefficient COP (COP when the heat source unit produces rated capacity) that has represented device performance. A method for calculating device performance in line with actual usage conditions has been introduced, which improves performance not only in specified load conditions such as rated operation, but also in operating conditions where load factor is low or load factor fluctuates, such as partial load operation. It is requested.

  Here, as a result of the examination by the inventors, in a heat exchanger where the wind speed distribution is non-uniform in the vertical direction, when the operating conditions change (in the case of partial load operation where the required capacity changes), in each region In consideration of the flow rate of the refrigerant, it was confirmed that the ratio of the optimum refrigerant flow rate to be supplied to each region changes according to the load factor. On the other hand, in Patent Document 1, the ratio of the refrigerant flow rate to the air flow rate can be optimized under a predetermined operating condition in which the opening diameter of each orifice is set, but the distribution ratio of the refrigerant amount to each region is as follows. It is fixed by the orifice, and changing the refrigerant flow rate ratio by changing operating conditions is not considered.

JP 2006-336936 A

  In the present invention, when the wind speed distribution of the heat source side heat exchanger is non-uniform in the vertical direction, the refrigerant can be more appropriately distributed to the heat source side heat exchanger even in partial load operation where the required capacity changes. And improving the period coefficient of performance as a refrigeration cycle apparatus.

  The refrigeration cycle apparatus of the present invention is a compressor, a blower fan for a heat source side heat exchanger, and a plurality of heat source side heat exchangers that exchange heat with air, each divided in the height direction and close to the blower fan Heat source side heat exchangers that are grouped by position to form a heat exchanger group, an expansion valve, a use side heat exchanger that exchanges heat with a heat transfer medium on the use side, a compressor, a heat source side heat exchanger, an expansion A valve and a refrigerant pipe that sequentially connects the use side heat exchanger to circulate the refrigerant, and a control device that controls the amount of refrigerant flowing into each of the heat exchanger groups according to the load factor.

  According to the present invention, the amount of refrigerant flowing into each of the heat exchanger groups grouped in the height direction is controlled according to the load factor, so even in partial load operation where the required capacity changes, in each region In consideration of the flow rate of the refrigerant, the refrigerant can be more appropriately distributed to the heat source side heat exchanger. Therefore, the period coefficient of performance as a refrigeration cycle apparatus can be improved.

The figure which shows the refrigerant circuit of refrigeration equipment Side view of heat source side heat exchanger The figure which shows the relationship between the height position of a heat exchanger with respect to a load factor, and a refrigerant | coolant flow rate ratio Cross section of the unit The figure which shows the refrigerant circuit of refrigeration equipment

  First, the inventor's examination content will be described. When a fan for the heat source side heat exchanger is arranged above the heat source side heat exchanger, the air velocity distribution of the heat source side heat exchanger is not uniform in the vertical direction, so the air passing through the heat source side heat exchanger In some cases, the ratio between the flow rate and the refrigerant flow rate is not uniform, and the heat transfer area of the heat source side heat exchanger cannot be used effectively. In such a case, the heat source side heat exchanger having a larger air flow rate than the lower side of the heat source side heat exchanger having a small air flow rate so that the ratio of the air flow rate passing through the heat source side heat exchanger and the refrigerant flow rate becomes equal. By distributing the refrigerant flow rate so as to increase the refrigerant flow rate on the upper side, the ratio of the air flow rate passing through the heat source side heat exchanger and the refrigerant flow rate can be made comparable, and the heat exchange efficiency can be improved.

  However, as a result of examination by the inventor, when the operating conditions change (in the case of partial load operation in which the required capacity changes), the ratio of the optimum refrigerant flow rate to be supplied to each region varies depending on the load factor. Was confirmed. FIG. 3 is a diagram showing a relationship between the height position of the heat exchanger and the refrigerant flow rate ratio with respect to the load factor, and is a result of simulation by the inventor. Specifically, on the premise that the wind speed is higher at the upper side of the heat exchanger and the wind speed is lower at the lower side of the heat exchanger, the height is different at load rates of 100%, 75%, 50%, and 25%. This is the ratio of the flow rate of the refrigerant flowing in each path when the refrigerant flows through the plurality of paths (number of paths: 34). 34 passes, the average is about 0.0294), the higher the average, the more refrigerant flows per unit time (that is, the higher the refrigerant flow rate), and the lower the average, the less refrigerant flows in that pass (The flow rate of the refrigerant is small). The horizontal axis in FIGS. 3 (1) to 3 (4) indicates the height position of the path in the heat exchanger, where path 1 is the uppermost path and path 34 is the lowermost path. It is. The vertical axis represents the refrigerant flow ratio. In any of FIGS. 3 (1) to (4), the flow rate / flow velocity of the refrigerant flowing in the upper region where the wind speed is higher is larger. Further, as the load factor decreases, the flow rate / flow velocity of the refrigerant increases in the upper region where the wind speed is high, and the flow rate / flow velocity of the flowing refrigerant decreases in the lower region where the wind speed distribution is small.

  According to this result, the heat source side heat exchange is increased by increasing the refrigerant flow rate ratio to the upper region where the refrigerant flow rate / flow velocity is larger than the lower region where the refrigerant flow rate / flow velocity is smaller as the load factor is reduced. The flow rate of the refrigerant in the entire vessel can be increased. Since the flow rate of the refrigerant in the entire heat source side heat exchanger increases, as a result, the heat transfer rate of the entire heat source side heat exchanger is improved, so that the heat exchange efficiency of the heat source side heat exchanger can be further improved.

  Therefore, for example, when the wind speed distribution of the heat source side heat exchanger is larger on the upper side than on the lower side, the upper side of the heat source side heat exchanger having a larger air flow rate than the lower side of the heat source side heat exchanger having a smaller air flow rate. Thus, by distributing the refrigerant flow rate to the refrigerant flow rate, the ratio of the air flow rate passing through the heat source side heat exchanger and the refrigerant flow rate can be made comparable, and the heat exchange efficiency can be improved. Further, as the load factor decreases, the entire heat source side heat exchanger is increased by increasing the refrigerant flow rate ratio to the upper region where the refrigerant flow rate / flow velocity becomes larger than the lower region where the refrigerant flow rate / flow velocity becomes smaller. Therefore, the heat exchange efficiency of the heat source side heat exchanger can be further improved.

  In addition, as shown in FIG. 3 (4), when the load is low (in the case of 25% load in FIG. 3), the refrigerant flow rate stays small near the lowermost part of the heat source side heat exchanger, and the refrigerant that has flowed in Does not contribute to heat exchange. Therefore, in the case of a low load, the refrigerant flow rate ratio is increased in the upper region where the flow rate / flow velocity of the refrigerant increases, and the heat exchanger in the lower region where the refrigerant stays is not used. Using a heat exchanger with a large refrigerant flow rate, heat exchange efficiency can be improved by improving the heat transfer coefficient, and the lower heat exchanger that does not contribute to heat exchange because the refrigerant flow rate stays small. Use can be avoided.

  In this way, by controlling the amount of refrigerant flowing into each region of the heat exchanger according to the load factor, even in partial load operation where the required capacity changes, the refrigerant is more appropriately supplied to the heat source side heat exchanger. Distribution becomes possible.

  Here, for example, when the refrigerant distribution ratio to each region is fixed using an orifice or the like so as to be optimal at 100% load, the air flow rate and the refrigerant flow rate passing through the heat source side heat exchanger at 100% load. However, even if the load is shifted to 50% load, the refrigerant distribution ratio to each region cannot be changed to further improve the heat exchange efficiency. In addition, when the load is shifted from 100% to 25%, the refrigerant flows into the lower heat exchanger that does not contribute to heat exchange due to the retention of the refrigerant, and the heat exchange efficiency deteriorates. On the other hand, for example, when the refrigerant distribution ratio to each region is fixed by using an orifice or the like so as to be optimal at 50% load, the flow rate of the upper heat exchanger decreases when shifting to 100% load. In the case where the side heat exchanger functions as a condenser), in the refrigerant path distributed so that the refrigerant flow rate becomes high, the refrigerant may not completely condense and reach the heat source side heat exchanger outlet.

  Thus, in the refrigeration cycle apparatus of the present invention, the compressor, the blower fan for the heat source side heat exchanger, and the plurality of heat source side heat exchangers for exchanging heat with air, each divided in the height direction. The heat source side heat exchangers that are grouped from the position close to the blower fan to form the heat exchanger group, the expansion valve, the use side heat exchanger that exchanges heat with the heat transfer medium on the use side, the compressor, the heat source side A refrigerant pipe that sequentially connects the heat exchanger, the expansion valve, and the use side heat exchanger to circulate the refrigerant; and a control device that controls the amount of refrigerant flowing into each of the heat exchanger groups according to the load factor; . According to the present invention, the amount of refrigerant flowing into each of the heat exchanger groups grouped in the height direction is controlled according to the load factor, so even in partial load operation where the required capacity changes, in each region The refrigerant can be more appropriately distributed to the heat source side heat exchanger in consideration of the flow rate of the refrigerant. Therefore, the period coefficient of performance as a refrigeration cycle apparatus can be improved.

  The first embodiment according to the present invention will be described below. FIG. 1 is a configuration diagram showing a refrigerant circuit configuration of a refrigeration apparatus. As shown in FIG. 1, the refrigeration apparatus 1 includes a compressor 2, a four-way valve 3 (refrigerant flow switching device), a heat source side heat exchanger 4, an expansion valve 5 (decompression device), and a use side. A heat exchanger 6 is provided, and these devices are sequentially connected by a refrigerant circuit 8 to constitute a refrigeration cycle apparatus.

  A refrigerant is sealed in the refrigerant circuit 8. As the refrigerant, HFC single refrigerant, HFC mixed refrigerant, HFO-1234yf, HFO-1234ze, natural refrigerant (for example, CO2 refrigerant), or the like can be used.

  As the refrigerant circulates through the refrigeration cycle channel by the compressor 2, cooling operation / heating operation is performed. As the compressor 2, a variable capacity compressor capable of capacity control is used. As the compressor, a piston type, a rotary type, a scroll type, a screw type, a centrifugal type, or the like can be used. The rotational speed is variable from low speed to high speed by capacity control by inverter control.

  The heat source side heat exchanger constituting the heat source side heat exchanger unit 90 </ b> A exchanges heat between the air on the heat source side and the primary side fluid flow path 61. The heat source side heat exchanger 4 uses a fin-type heat exchanger in which a plurality of laminated plate-like fins 41 and a plurality of heat transfer tubes 42 penetrating the fins are provided in multiple stages. Many refrigerant paths are configured by connecting ends with bend pipes or the like. The refrigerant flows in the refrigerant path (primary side fluid flow path 61), and the air flows between the plate-like fins 41 that are blown by the blower fan (blower device) and stacked. In the heat source side heat exchanger 4, air and the refrigerant exchange heat through the fins 41 and the heat transfer tubes 42, and function as a condenser during the cooling operation and function as an evaporator during the heating operation.

  The heat source side heat exchanger 4 includes a plurality of fans 95a, 95b, 95c, and 95d corresponding to the plurality of heat source side heat exchangers.

  The use side heat exchanger 6 exchanges heat between the refrigerant flowing in the primary side fluid passage 61 and the heat transfer medium flowing in the secondary side fluid passage 62. The usage-side heat exchanger 6 includes a plate-type heat exchanger that performs heat exchange by flowing through a plurality of flow paths in which refrigerant and a heat medium are alternately partitioned by plates, a shell-tube heat exchanger, and the like. Can be used. Although not shown, the heat transfer medium circulates between the load-side heat exchanger (for example, an air conditioner) and the use-side heat exchanger by a circulating means such as a pump, and transfers heat. The use side heat exchanger functions as an evaporator during cooling operation and as a condenser during heating operation.

  The refrigeration apparatus 1 includes a temperature sensor that detects the outdoor air temperature, the refrigerant temperature, and the temperature of the heat medium. A temperature detection signal detected by the temperature sensor is input to the control device. Moreover, the refrigeration apparatus 1 includes a pressure sensor that detects the refrigerant pressure of the refrigeration cycle. A pressure detection signal detected by the pressure sensor is input to the control device 10.

  The control device 10 determines the operation mode of the refrigeration apparatus 1 according to the required load, and according to the determined operation mode, various valves (four-way valve 3, expansion valve 5, refrigerant flow rate control valves 101 to 102 and 104 to 106). The state (opening degree), the rotational speed of the compressor 2, and the rotational speeds of the fans 95a, 95b, 95c, and 95d of the heat source side heat exchanger are controlled. In addition, detection amounts detected by the temperature sensor and the pressure sensor are input to the control device 10 to control various operations of the refrigeration apparatus 1. The refrigeration apparatus 1 controls the operation state of the refrigeration apparatus in accordance with the required load, and controls the rotational speed and the number of operating units of the fans 95a, 95b, 95c, and 95d according to instructions from the control apparatus.

  A case where the cooling operation is performed by the refrigeration apparatus 1 will be described as an example. The high-temperature and high-pressure gas refrigerant discharged from the compressor 2 passes through the four-way valve 3 and the header 71 and flows into the heat source side heat exchanger 4 that functions as a condenser. The refrigerant flowing into the heat source side heat exchanger is condensed and liquefied by releasing heat to the outside air. The liquefied refrigerant is decompressed by the expansion valve 5 adjusted to a predetermined opening degree, enters a low-temperature and low-pressure gas-liquid two-phase state, and flows into the primary side flow path 61 of the use side heat exchanger 6. The refrigerant flowing through the use side heat exchanger 4 evaporates and vaporizes by absorbing heat from the heat transfer medium flowing through the secondary side flow path 62. The vaporized refrigerant is sucked into the compressor 2 through the four-way valve 3 and is compressed again by the compressor 2 to become a high-temperature and high-pressure gas refrigerant. In this way, the refrigeration cycle apparatus of the refrigeration apparatus 1 is formed. Note that the refrigeration cycle apparatus can function as a heating operation by switching the four-way valve 3 and circulating the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 in the direction opposite to that during the cooling operation.

  In this embodiment, as shown in FIG. 1, the heat source side heat exchanger 4 divides a plurality of heat source side heat exchangers in the height direction, and a plurality of heat source side heat exchanges divided in the height direction. The heat exchanger group is configured by grouping the heat exchangers from above. That is, the heat source side heat exchanger 4 includes heat exchanger groups 401, 402, and 403 in which heat exchangers having the same approximate height are grouped. In addition, each heat exchanger group includes refrigerant distribution channels 81, 82, and 83 and refrigerant merge channels 84, 85, and 86, and flow control valves 101 to 106 are provided at both ends of the heat exchanger group, respectively. . The uppermost heat exchanger group 401 will be described as an example. The heat exchanger group 401 is composed of four heat source side heat exchangers (HA1, HB1, HC1, and HD1), and a refrigerant distribution channel 81 on the upstream side. And a flow rate control valve 101, and a refrigerant confluence channel 84 and a flow rate control valve 104 are provided on the downstream side.

  In addition, in the present Example, although the heat source side heat exchanger was divided | segmented into plurality in the height direction, the structure which changed the heat-transfer area after a division | segmentation for every height of a heat exchanger may be sufficient. For example, if the front area of the heat exchangers (HA1, HB1, HC1, HD1) constituting the uppermost heat exchanger group 401 is at least 50% or more of the front area of the entire heat exchanger, the required cooling is performed. When the capacity is low (when the load is low), the refrigerant is supplied only to the upper heat exchanger group (for example, 401 and 402), and flows into the heat transfer tubes of the heat exchangers constituting the heat exchanger group 401 and 402. Since the amount of refrigerant increases, the flow rate in the pipe increases, the heat transfer coefficient on the refrigerant side improves, and good heat exchange is performed, and the required capacity can be obtained.

  The opening degree of the flow control valves 101 to 106 is controlled by the control device 10 according to the operating state of the refrigeration apparatus, and the optimum refrigerant amount is distributed. Further, the heat exchangers constituting the heat exchanger group (for example, HA1, HB1, HC1, HD1 in the heat exchanger group 401) are distributed from the refrigerant distribution flow path 81 through 81a, 81b, 81c, 81d, respectively. Is done. The heat exchangers of the same heat exchanger group have the same approximate height, and the installation location of the branching portion 171 is also at the same height, so that the refrigerant is distributed to the heat exchangers without being affected by the head difference. Is possible. Moreover, the effective heat-transfer area of a heat exchanger is ensured by adjusting the opening degree of the flow control valves 101-106 so that suitable refrigerant | coolant amount may be distributed with respect to the heat-transfer surface of each heat exchanger. , Driving efficiency can be improved.

  FIG. 2 shows a schematic diagram of the heat source side heat exchanger unit 90A of the refrigeration apparatus. The plurality of refrigerant paths of the heat source side heat exchanger 4 are branched from the branch portions 171a, 172a, 173a via the branch pipes 81a, 82a, 83a on the refrigerant inlet side of the heat exchanger, and flow into the heat source side heat exchanger 4 To do. On the refrigerant outlet side of the heat source side heat exchanger 4, a plurality of refrigerant paths merge at the junctions 181a, 182a, and 183a, and are connected to the junction pipes 84a, 85a, and 86a.

  FIG. 4 is a cross-sectional view of the unit 94 in which the fan 95 is installed at the upper position of the heat source side heat exchanger 4. Air flows into the heat exchanger groups 401, 402, and 403 of the heat source side heat exchanger 4 installed vertically with respect to the unit housing from the outside of the housing, via the fins and the heat transfer tubes of the heat source side heat exchanger. After exchanging heat with the refrigerant, the air is blown by the fan 95 installed at the upper part of the housing and flows out of the unit. The flow rate of the air passing through the heat exchanger is distributed from the upper position to the lower position. That is, in the upper air passages 91 and 92 close to the fan, the flow velocity is faster than the average air flow velocity and heat exchange is promoted. However, in the lower position 93, the air flow velocity is lower than the average flow velocity and heat exchange is reduced. .

  Here, the air passing through the heat source side heat exchanger is distributed by distributing the refrigerant flow rate to the refrigerant flow rate by the upper side of the heat source side heat exchanger having the larger air flow rate than the lower side of the heat source side heat exchanger having the smaller air flow rate. Heat exchange efficiency can be improved by making the ratio of the flow rate and the refrigerant flow rate comparable. Further, as the load factor decreases, the entire heat source side heat exchanger is increased by increasing the refrigerant flow rate ratio to the upper region where the refrigerant flow rate / flow velocity becomes larger than the lower region where the refrigerant flow rate / flow velocity becomes smaller. Therefore, the heat exchange efficiency of the heat source side heat exchanger can be further improved.

  Furthermore, in the case of a low load, the refrigerant flow rate remains small in the vicinity of the lowermost part of the heat source side heat exchanger, and the refrigerant flowing in does not contribute to heat exchange. Accordingly, the refrigerant flow rate ratio is increased in the upper region where the flow rate / flow velocity of the refrigerant increases, and the heat exchanger in the lower region where the refrigerant stays may be unused. Use of a heat exchanger with a large refrigerant flow rate can improve the heat exchange efficiency by improving the heat transfer coefficient, and use of a lower heat exchanger that does not contribute to heat exchange because the refrigerant flow rate remains small Can be avoided.

  As described above, in the refrigeration cycle apparatus (refrigeration apparatus) of the present embodiment, the plurality of heat source side heat exchangers are divided in the height direction, and the plurality of heat source side heat exchangers divided in the height direction are divided. Are grouped from above to constitute a heat exchanger group, and the amount of refrigerant flowing into each of the heat exchanger groups is controlled according to the load of the use side heat exchanger. Thereby, since the amount of refrigerant flowing into each of the heat exchanger groups grouped in the height direction is controlled according to the load of the use side heat exchanger, even in the partial load operation where the required capacity changes, In consideration of the flow rate of the refrigerant in the region, the refrigerant can be more appropriately distributed to the heat source side heat exchanger. Therefore, the period coefficient of performance as a refrigeration cycle apparatus can be improved.

  Next, a second embodiment according to the present invention will be described. In the present embodiment, in the first embodiment, further, from the heat exchanger group 401 located on the uppermost side among the heat exchanger groups grouped in the height direction according to the load factor of the refrigeration cycle apparatus. Use in order. In the heat exchanger group 403 that is not used, the refrigeration cycle apparatus is operated using the other heat exchanger groups 401 and 402 in a state where the refrigerant is discharged from the heat exchanger group 403.

  As shown in FIG. 3, when the wind speed distribution of the heat source side heat exchanger is larger on the upper side than on the lower side, the flow rate of the refrigerant is larger on the upper heat source side heat exchanger. In the case of a 25% load, the flow rate of the refrigerant stays small in the vicinity of the lowermost part of the heat source side heat exchanger, and the refrigerant flowing in does not contribute to heat exchange.

  Therefore, in the refrigeration cycle apparatus of the present embodiment, the heat exchanger group 401 located in the uppermost position among the heat exchanger groups grouped in the height direction is selectively selected in order according to the load factor of the refrigeration cycle apparatus. Used for. In an operating situation where the load factor of the refrigeration cycle apparatus is small, heat exchangers with a large refrigerant flow rate are used in order from the heat exchanger group located at the uppermost position among the heat exchanger groups grouped in the height direction. As a result, the heat exchange efficiency can be improved by improving the heat transfer coefficient, and the use of a heat exchanger group that does not contribute to heat exchange because the flow rate of the refrigerant stays small can be avoided.

  Furthermore, in the refrigeration cycle apparatus of the present embodiment, in the heat exchanger group that is not used, the refrigeration cycle apparatus is operated using another heat exchanger group in a state where the refrigerant is discharged from the heat exchanger group. . If the flow rate of the refrigerant stays small and the refrigerant remains in the heat exchanger group that does not contribute to heat exchange, the amount of refrigerant circulating in the other heat exchanger group that contributes to operation decreases, and the heat Exchange efficiency decreases. In order to avoid this, if the amount of refrigerant charged is increased in advance, it becomes necessary to enclose unnecessary refrigerant in excess of the refrigerant that is originally required in the refrigeration cycle apparatus. As described above, by operating the refrigeration cycle apparatus using another heat exchanger group in a state in which the refrigerant is discharged from the heat exchanger group that is not used, the amount of refrigerant enclosed in the refrigeration cycle apparatus can be optimized. , A decrease in heat exchange efficiency can be avoided.

  Specifically, in the refrigeration apparatus 1, the flow control valve 103 of the refrigerant distribution flow path 83 is closed, and the heat exchanger group 403 is configured to operate for a certain period of time with the opening of the expansion valve 5 being reduced. The amount of refrigerant remaining in the heat exchanger is reduced by lowering the pressure inside the heat exchanger from the pressure state at the required capacity. Next, the supply of the refrigerant to the heat exchanger group 403 is stopped by closing the flow control valve 106 of the refrigerant confluence channel 86. Thereafter, a cooling operation corresponding to the required capacity is performed. The refrigerant flows into the heat exchanger groups 401 and 402 to exchange heat, and refrigerant distribution to the heat exchanger group 401 and the heat exchanger group 402 is to adjust the opening degree of the flow control valves 101 and 102. To do.

  Thus, by not using the lower heat exchangers (HA3, HB3, HC3, HD3), the amount of refrigerant flowing into the heat exchanger tubes of the heat exchangers constituting the heat exchanger groups 401, 402 increases. Therefore, the flow rate in the pipe increases, the heat transfer coefficient on the refrigerant side is improved, and good heat exchange is performed.

  Further, the fact that the lower heat exchangers (HA3, HB3, HC3, HD3) are not used prevents the refrigerant from staying in the lower heat exchanger and optimizes the amount of refrigerant charged in the refrigeration system. It becomes possible. Usually, the refrigerant filling amount of the refrigeration apparatus is determined so that the capacity required by the system during the refrigeration cycle, the cooling operation, and the heating operation can be satisfied. The air heat exchanger during the cooling operation acts as a condenser to liquefy the refrigerant from the superheated gas state. At the outlet of the heat exchanger, a plurality of refrigerant pipes that have flowed out from the respective paths join the joining portion 181. For example, when the junction 181 is at a position higher than the path outlet of the heat exchanger, the liquid refrigerant may stay in the pipe from the path outlet of the heat exchanger to the junction, and the refrigerant may not flow easily. . Such a state becomes conspicuous because the amount of refrigerant flowing in one path decreases under a low load condition, and the refrigerant stays in the lower path of the heat exchanger and the heat transfer area is not effectively used. Since this staying refrigerant stays inside the heat exchanger without circulating in the refrigeration cycle, it is necessary to increase the amount of refrigerant enclosed in order to achieve the cycle conditions according to the required capacity, the amount of refrigerant enclosed becomes excessive, This is a negative factor in terms of cost and environmental impact.

  As shown in the present embodiment, the fact that the lower heat exchangers (HA3, HB3, HC3, HD3) are not used prevents refrigerant stagnation inside the heat exchanger and reduces the operating conditions according to the load factor. In addition, since a suitable heat transfer area can be ensured, the efficiency of heat exchange at a low load can be improved, and the operation efficiency can be increased.

  Next, a third embodiment according to the present invention will be described. In the present embodiment, unlike the refrigerant distribution circuit of the first embodiment shown in FIG. 1, one refrigerant distribution flow path 81 is branched into two flow paths by the branching section A, and then further branched section D. And it is further branched into two by the branch part G. By providing a flow rate adjusting valve for each branched flow path, it is possible to further control the refrigerant flow rate to a specific heat exchanger among the refrigerant flow rates distributed to the heat exchanger group.

  In each of the above embodiments, the pipe diameter of the refrigerant distribution flow path 81, 82, 83 to the heat exchange groups 401, 402, 403 is the pipe of the refrigerant distribution flow path 81 to the heat exchanger group 401 at the upper position. The diameter is large, the pipe diameter of the refrigerant distribution flow path 81 to the heat exchanger group 402 at the middle position is medium, and the pipe diameter of the refrigerant distribution flow path 83 to the heat exchanger group 403 at the lower position is small. You can also. By adopting such a configuration, a difference occurs in the pressure loss during refrigerant flow depending on the pipe diameter. Therefore, the amount of refrigerant supplied to the heat exchanger group 401 at the upper position is increased and the heat exchanger group 403 at the lower position is moved to. It is possible to reduce the refrigerant supply amount. More refrigerant is supplied to the upper heat exchanger group having a larger pipe diameter than the lower heat exchanger group. For this reason, when the wind speed distribution of the heat source side heat exchanger is larger on the upper side than on the lower side, the refrigerant is supplied in accordance with the wind speed distribution, so the reduction in exchange heat due to non-uniform wind speed distribution is suppressed. Thus, it is possible to contribute to improvement of the coefficient of performance.

  In each of the above embodiments, as an application device of the refrigeration cycle apparatus of the present embodiment, a refrigeration apparatus 1 that supplies a heat medium exchanged by the use-side heat exchanger 6 to load-side equipment (not shown). Although described as a chiller unit), it can also be applied to an air conditioner or the like.

Refrigeration device 1, compressor 2, four-way valve 3, heat source side heat exchanger 4 expansion valve 5, utilization side heat exchanger 6, refrigerant circuit 8, control device 10, control valve 11, control valve 12, check valve 13, Plate fin 4, heat transfer tube 42, primary side fluid flow path 61, secondary side fluid flow path 62, header 71, header 72, refrigerant distribution flow paths 81, 82, 83, 84, 85, 86, bypass circuit 87 , Heat exchanger units 90a, 90b, 90c, 90d, fans 95a, 95b, 95c, 95d, flow control valves 101, 102, 103, 104, 105, 106, heat exchanger groups 401, 402, 403, branching part A ~ T, heat source side heat exchangers HA1, HA2, HA3, heat source side heat exchangers HB1, HB2, HB3, heat source side heat exchangers HC1, HC2, HC3, heat source side heat exchangers HD1, HD2, HD,

Claims (8)

A compressor,
A blower fan for the heat source side heat exchanger;
A plurality of heat source side heat exchangers that exchange heat with air, each of which is divided in a height direction and grouped from a position close to the blower fan to constitute a heat exchanger group, and
An expansion valve;
A use side heat exchanger for exchanging heat with a heat transfer medium on the use side;
A refrigerant pipe for circulating the refrigerant by sequentially connecting the compressor, the heat source side heat exchanger, the expansion valve, and the use side heat exchanger;
A control device for controlling the amount of refrigerant flowing into each of the heat exchanger groups according to a load factor;
Equipped with a,
Each of the heat exchanger groups includes an inflow control device on the refrigerant inflow side and an outflow control device on the refrigerant outflow side,
As the load factor increases, the heat exchanger group located on the uppermost side is used and operated in order,
Operate with the refrigerant discharged from the heat exchanger group not used,
A refrigeration cycle apparatus that discharges refrigerant from the unused heat exchanger group by closing the inflow control device and then closing the outflow control device in a state where the compressor is driven . In claim 1,
The said control apparatus is a refrigerating-cycle apparatus which increases the inflow rate of the refrigerant | coolant to the said heat exchanger group located in an upper side, so that the said load factor is small. In claim 1,
The control device increases the ratio of refrigerant flowing into the heat exchanger group located on the upper side, and increases the ratio of refrigerant flowing into the heat exchanger group with higher wind speed as the load factor decreases. apparatus. In claim 1,
The blower fan is disposed above the heat source side heat exchanger,
The said control apparatus is a refrigerating-cycle apparatus which increases the inflow rate of the refrigerant | coolant to the said heat exchanger group located in an upper side, so that the said load factor is small. In claim 1,
The blower fan is disposed above the heat source side heat exchanger,
The control device increases the proportion of refrigerant flowing into the heat exchanger group located on the upper side, and increases the proportion of refrigerant flowing into the heat exchanger group located on the upper side as the load factor decreases. Cycle equipment. According to any one of claims 1 to 5,
The said control apparatus is a refrigerating-cycle apparatus which controls the refrigerant | coolant amount which flows in into each of the said heat exchanger group by controlling the said inflow control apparatus. A refrigeration apparatus comprising the refrigeration cycle apparatus according to any one of claims 1 to 6 . An air conditioner including the refrigeration cycle apparatus according to any one of claims 1 to 6.