JP2007187353A - Freezer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent freezing of water refrigerant in a plate type heat exchanger to which a plurality of refrigeration circuits are connected. <P>SOLUTION: In the freezer comprising a plurality of refrigeration circuits for circulating refrigerant by successively connecting a compressor 1, a heat source-side heat exchanger 2, an expansion device 3, and a using-side heat exchanger 4, in which a cooled medium heat-exchanged by each using-side heat exchanger 4 is supplied to a load, each using-side heat exchanger 4 includes refrigerant passages for passing a refrigerant and cooled medium passages for passing the cooled medium alternately disposed between a plurality of plates opposed to each other, all the cooled medium passages of the using-side heat exchanger being connected at the inlet side and outlet side of the plates, respectively to form the plate type heat exchanger. This freezer comprises a temperature estimation means for inputting detection temperatures at the inlet side and outlet side of the cooled medium in the plate type heat exchanger and an operation capacity of each refrigeration circuit, and arithmetically estimating the cooled medium temperature on the outlet side of the cooled medium passages of each using-side heat exchanger. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus used in, for example, a refrigerator or an air conditioner in a living room, and more particularly to a refrigeration apparatus suitable for preventing freezing of a plate heat exchanger that exchanges heat between a refrigerant and a medium to be cooled.

  In general, a refrigeration system is composed of a refrigeration circuit that sequentially connects a compressor, a heat source side heat exchanger, a decompression device, and a usage side heat exchanger by refrigerant piping, a usage side heat exchanger, a circulation pump, and a heat load by refrigerant piping. A refrigeration operation is performed by supplying a cooling medium (hereinafter, appropriately referred to as a water refrigerant), which is configured to include a water circulation circuit to be connected and heat-exchanged with the refrigerant by the use side heat exchanger, to a heat load.

  In such a refrigeration apparatus, in order to prevent freezing of the water refrigerant in the use side heat exchanger, the temperatures of the inlet and outlet portions of the water refrigerant flowing into the use side heat exchanger are detected, There is known a refrigeration apparatus having a function of stopping the operation of a refrigeration circuit when a difference in temperature at an outlet becomes a predetermined value or more (see Patent Document 1).

  On the other hand, a refrigeration apparatus configured by connecting a plurality of refrigeration circuits via a common use side heat exchanger is known. In this type of refrigeration apparatus, for example, a plate heat exchanger is used as a use side heat exchanger.

  In this plate heat exchanger, for example, a plurality of plates are arranged in parallel, and refrigerant flow paths for refrigerant flowing from each refrigeration circuit and water refrigerant flow paths for water refrigerant flowing from the water circulation circuit are alternately arranged. The water refrigerant flow path is configured to communicate with each other by a pair of headers formed at both ends of each plate. According to this, the water refrigerant introduced into the plate heat exchanger is diverted in one header and led to a plurality of water refrigerant flow paths, and then merges again in the other header, to the heat load. Supplied.

  Thus, when a plate-type heat exchanger is used as the use-side heat exchanger, for example, the space of the water channel can be reduced, and a compact and high heat exchange efficiency can be obtained.

JP 2000-121175 A

  However, in the plate heat exchanger in which a plurality of refrigeration circuits are connected as described above, even if the temperature of the outlet portion after the joining of the water refrigerant heat-exchanged with each refrigeration circuit is detected, Since the refrigeration capacity may vary depending on the operating capacity, there is a problem that sufficient freezing prevention cannot be achieved. For example, when one unit stops while operating a plurality of refrigeration circuits, if the operating capacity of another refrigeration circuit is increased in order to keep the temperature at the outlet of the heat exchanger constant, The capacity is increased and local freezing due to supercooling of the water refrigerant may occur.

  An object of the present invention is to prevent freezing of water refrigerant in a plate heat exchanger to which a plurality of refrigeration circuits are connected.

  In order to solve the above problems, the present invention includes a plurality of refrigeration circuits that sequentially connect a compressor, a heat source side heat exchanger, an expansion device, and a use side heat exchanger to circulate the refrigerant, and each use side heat exchanger In the refrigeration apparatus that supplies the heat-exchanged medium to be cooled to the load, each user-side heat exchanger has a plurality of plates arranged to face each other and a refrigerant flow path through which the refrigerant flows and a medium through which the medium to be cooled flows. The cooling medium flow paths are arranged alternately, and the cooling medium flow paths of all the use side heat exchangers are communicated with each other on the inlet side and the outlet side of the plate to form a plate heat exchanger. Input the detected temperatures on the inlet and outlet sides of the cooling medium of the exchanger and the operating capacity of each refrigeration circuit, and calculate the temperature of the cooling medium on the outlet side of the cooling medium flow path of each use side heat exchanger by calculation A temperature estimation means for estimation is provided.

  That is, the cooling medium temperature on the outlet side of the cooling medium flow path of each use side heat exchanger is the detected temperature on the inlet side and outlet side of the cooling medium of the plate heat exchanger, and the operating capacity of each refrigeration circuit Therefore, the temperature of each cooling medium can be detected as an estimated value by inputting these arithmetic expressions into the temperature estimating means in advance. . Then, based on the estimated value of the cooling medium temperature, for example, by appropriately adjusting the operating capacity of each refrigeration circuit, a decrease in the water temperature of the cooling medium can be suppressed, so that freezing can be prevented.

  In addition, by using the operation capacity of each refrigeration circuit as input information, for example, the operation stop state of the refrigeration circuit can also be determined, and if the same processing is performed based on this, an estimated value of the cooling medium temperature is detected. can do.

  In this case, the temperature estimation means includes control means for changing the operating capacity of the refrigeration circuit based on the estimated value when the estimated value of the temperature of the cooling medium is equal to or lower than the set temperature. According to this, since the operation capacity of each refrigeration circuit can be automatically set optimally based on the estimated value, it is possible to more reliably prevent the use side heat exchanger from freezing. Further, the temperature estimation means may include a control means for stopping the operation of the refrigeration circuit when the estimated value of the temperature of the cooling medium is equal to or lower than the set temperature.

  In addition, the plate heat exchanger may be configured, for example, by arranging a pair of common headers that allow the cooling medium flow paths at both ends of the plates of each use-side heat exchanger to communicate with each other. The cooling medium passages at both ends of the plates of each use side heat exchanger are communicated with each other by a pair of headers, and the headers of all the use side heat exchangers are communicated with each other. May be.

  According to the refrigeration apparatus of the present invention, water refrigerant can be prevented from freezing in a plate heat exchanger to which a plurality of refrigeration circuits are connected.

(First embodiment)
Hereinafter, a first embodiment of a refrigeration apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a refrigeration cycle system diagram showing an embodiment of a refrigeration apparatus to which the present invention is applied.

  The refrigeration apparatus of the present embodiment includes two refrigeration circuits (No. 1 machine 21 and No. 2 machine 22) and a control device 12. Each refrigeration circuit is configured by sequentially connecting a compressor 1, a heat source side heat exchanger 2, an expansion device 3, and a usage side heat exchanger 4 by refrigerant piping, and is connected via a common usage side heat exchanger 4. ing. A blower 5 is disposed in the vicinity of the heat source side heat exchanger 2.

  The use side heat exchanger 2 is used as a heat exchanger of a water circulation circuit (not shown), and the water refrigerant flowing through the water circulation circuit exchanges heat with the refrigerant of each refrigeration circuit via the use side heat exchanger 2. It has become. The water circulation circuit is configured, for example, by connecting the use-side heat exchanger 4, the circulation pump, and the heat load sequentially by refrigerant piping.

  The thermistors 6 and 7 are respectively installed at the inlet portion of the water refrigerant flowing into the utilization side heat exchanger 4 from the water circulation circuit and the outlet portion where the water refrigerant flows out of the utilization side heat exchanger 4, and the utilization side heat exchanger. The water temperature of the water refrigerant flowing into the water 4 and the water temperature of the water refrigerant flowing out of the use side heat exchanger 4 are detected. The compressors 1 and the thermistors 6 and 7 of the first machine 21 and the second machine 22 are electrically connected to the control device 12, respectively.

  FIG. 3 is a schematic diagram of the internal structure of the use side heat exchanger 4 of FIG. The use side heat exchanger 4 of the present embodiment is configured as a plate heat exchanger in which a plurality of plates (8a, 8b, 8c...) Face each other with a predetermined interval and are stacked. Between each plate 8, there are refrigerant flow paths (9b, 9d, 9f...) Through which the refrigerant in the refrigeration circuit flows and water refrigerant flow paths (9a, 9c, 9e...) Through which the water refrigerant in the water circulation circuit flows. Alternatingly arranged. Refrigerant introduction pipes 23 and refrigerant discharge pipes 24 for supplying and discharging refrigerant are respectively inserted into the plates 8 from the stacking direction of the plates, and the refrigerant flow paths between the plates are connected to the refrigerant introduction pipes. 23 and the refrigerant discharge pipe 24. Between the plates 8 serving as the refrigerant flow path, the end portions are sealed to prevent the water refrigerant from entering.

  A partition plate 8 i is provided in the center in the stacking direction of the plates 8 in parallel with the plates 8. Thereby, the refrigerant | coolant flow path of the utilization side heat exchanger 4 is divided | segmented into the 1st machine side and the 2nd machine side, and it is comprised so that it may become a mutually independent refrigerant | coolant flow path.

  On the other hand, a common header 25 and a common header 26 are provided at one end on the opening side between the plates 8 and the other end opposite to each other. The common headers 25 and 26 connect all the plates 8 including the partition plate 8i. Covered and formed. That is, the common headers 25 and 26 are communicated with each other through all the water refrigerant channels, and no partition on the first and second machine sides is provided as in the refrigerant channel.

  Here, since the flow resistance of the water refrigerant on the No. 1 unit 21 side and the flow resistance of the water refrigerant on the No. 2 unit 22 side are configured to be the same, the use-side heat exchanger 4 is configured on the No. 1 side and the No. 2 side. The amount of water refrigerant flowing through the water refrigerant channel (flow rate per unit time) is the same. In addition, the No. 1 machine 21 and the No. 2 machine 22 are configured so that the refrigerant amounts (flow rates per unit time) flowing through the refrigerant flow paths become equal if the operating capacities of the compressors are set to be the same.

  In such a configuration of the use-side heat exchanger 4, the water refrigerant that has flowed into the header 25 through the inlet of the first unit is divided and flows into all the water refrigerant channels (solid arrows). After being merged, it is discharged from the Unit 1 side through the outlet. On the other hand, the refrigerant that has flowed in from the refrigerant introduction pipes 23 of the first machine 21 and the second machine 22 flows through the refrigerant flow path in the direction opposite to the water refrigerant (dotted arrow) and is discharged from the refrigerant discharge pipe 24, respectively. .

  By the way, the temperature of the water refrigerant flowing through the use side heat exchanger 4 varies depending on the operating capacity of each unit, the temperature of the water refrigerant flowing in, and the like. For this reason, in order to prevent freezing of the water refrigerant in the use side heat exchanger 4, the outlet temperature of the water refrigerant exchanged with the refrigerant of each unit, for example, the cold water outlet temperature 10 at the outlet of the water refrigerant flow path, A method of detecting each of 11 is conceivable. However, these positions are, for example, extremely narrow areas in terms of structure, so that a sufficient space for installing the thermistor cannot be secured. Even if it can be installed, the cold water that has flowed through the water refrigerant flow path on each unit side joins in the header 26, making it difficult to accurately detect the water temperature.

  Therefore, in this embodiment, the thermistors 6 and 7 are installed on the inlet side of the header 25 and the outlet side of the header 26, respectively. Thereby, the temperature of the water refrigerant at the time of flowing into the use-side heat exchanger 4 and the temperature of the water refrigerant after passing through the water refrigerant flow path on each unit side are detected.

  First, when the compressor 1 of the No. 1 machine 21 and the No. 2 machine 22 is operating with the same capacity, the cold water outlet temperatures 10 and 11 on each machine side are the same temperature, and the detected temperature of the thermistor 7 after merging is cold water. It becomes the same as outlet temperature 10 and 11. Therefore, if the temperature of the thermistor 7 is detected, the cold water outlet temperatures 10 and 11 on each unit side can be detected.

  On the other hand, when the compressor 1 of the No. 2 machine 22 stops, the cold water outlet temperature 10 on the No. 1 side is lower than the temperature detected by the thermistor 6 because the water refrigerant exchanges heat with the refrigerant. The cold water outlet temperature 11 on the side is the same as the detected temperature of the thermistor 6 because the water refrigerant does not exchange heat. That is, the detected temperature of the thermistor 7 detects the average temperature of the chilled water outlet temperatures 10 and 11 because the water refrigerant flow rate on each unit side is the same. Therefore, the cold water outlet temperature 10 on the first unit side cannot be detected.

  Next, an example of the control operation of the control device 12 will be described with reference to the drawings.

  FIG. 5 is a flowchart showing a control operation when a plurality of refrigeration circuits equipped with the compressor 1 having no capacity control function are combined. The operation of the refrigeration circuit and the water circulation circuit is started when an operation start command is input from the control device 12. When these operations are started, the thermistors 6 and 7 detect the water refrigerant temperature of each part (hereinafter abbreviated as T6 and T7 as appropriate) (step S1). Next, the control device 12 detects the number m of compressors connected thereto and the number n of compressors currently in operation (step S2). Then, the cold water outlet temperature 10, 11 (hereinafter, abbreviated as T10, T11 as appropriate) of the unit in operation is obtained by the following equation 1 based on the detected temperature and the state of the compressor.

例えば、圧縮機１の接続台数２台、運転台数２台であれば、Ｔ１０はＴ７となる。また、圧縮機１の接続台数２台、運転台数１台であれば、Ｔ１０はＴ６−２×（Ｔ６−Ｔ７）となり、Ｔ６，Ｔ７を検知することにより、Ｔ１０の温度を演算により求める（ステップＳ３）。

For example, if the number of connected compressors 1 is two and the number of operating units is two, T10 is T7. Further, if the number of connected compressors 1 is two and the number of operating units is 1, T10 becomes T6-2 × (T6-T7), and the temperature of T10 is calculated by detecting T6 and T7 (step) S3).

  Then, it is determined whether or not T10 calculated in step S3 is equal to or lower than a predetermined temperature Ta (step S4). If it is equal to or lower than Ta, it is determined that the medium to be cooled is supercooled, and the compressor 1 Is stopped (step S5). On the other hand, if T10 is higher than the predetermined temperature Ta in the determination in step S4, the determination is made again from step S1.

  For example, if the number of connected compressors 1 is two and the number of operating units is two, T10 is T7. If the number of connected compressors 1 is two and the number of operating units is one, T10 becomes T6-2 × (T6-T7), and the temperature of T10 is calculated by detecting T6 and T7 (step S3). ).

  Next, a case where a capacity control function is installed in the compressor 1 will be described. When the compressors 1 of the No. 1 machine 21 and the No. 2 machine 22 are operated with the same capacity, the cold water outlet temperatures 10 and 11 on the side of each machine are the same temperature, and the detected temperature of the thermistor 7 after the merging is the cold water outlet temperature. 10 and 11 are the same. However, for example, when the compressor 1 is operated with the operating capacity of the first unit 21 being 100% and the second unit being 50%, the chilled water outlet temperatures 10 and 11 on each unit side are different and the chilled water outlet temperature 10 is the chilled water outlet. The temperature of the chilled water outlet temperatures 10 and 11 cannot be detected only by the detected temperature of the thermistor 7 after merging.

  FIG. 6 is a flowchart showing the control operation when two refrigeration circuits equipped with a capacity control function are used in the compressor 1 (two cycles).

  The operation of the refrigeration circuit and the water circulation circuit is started when an operation start command is input from the control device 12. When these operations are started, T6 and T7 are detected by the thermistors 6 and 7 (step S21). Next, the control device 12 detects the number n of the currently operating compressors and determines whether or not both are operating (step S22). If only one unit is operated, for example, T10 of the first unit in operation is calculated in the same manner as step S3 in FIG. 5 (step S23). Then, it is determined whether or not T10 is equal to or lower than the predetermined temperature Ta (step S24). If T10 is equal to or lower than the predetermined temperature Ta, it is determined that the medium to be cooled is supercooled, and the compressor 1 is operated. Stop (step S25). When T10 is higher than the predetermined temperature Ta in the determination in step S24, the determination is made again from step S1.

  On the other hand, if both units are operating in the determination of step S22, the control device 13 detects the operating capacity of each compressor 1 (step S26). Here, the detected temperatures T6 and T7 of the thermistors 6 and 7, the capacity R1 of the No. 1 compressor, the capacity R2 of the No. 2 compressor, and the cold water outlet temperatures T10 and T11 on the side of each No. 1 hold the following relationship. Here, Equation 2 represents that the temperature difference between the inlet side and outlet side of the water refrigerant on each unit side is proportional to the operating capacity of the compressor 1, and Equation 3 represents the cold water of the water refrigerant on each unit side. It shows that the average of the outlet temperature is the cold water outlet temperature after merging. The cold water outlet temperatures T10 and T11 of each unit are obtained by calculation according to Equations 2 and 3 (step S27).

次に、例えば、Ｔ１０が所定温度Ｔａ以下であるか否かを判定する（ステップＳ２８）。ここで、演算温度Ｔ１０が所定温度Ｔａ以下と判定された場合、被冷却媒体が過冷却されていると判断し、１号機の圧縮機１の運転を停止し（ステップＳ２９）、次のステップＳ３０へと進む。

Next, for example, it is determined whether T10 is equal to or lower than a predetermined temperature Ta (step S28). Here, when it is determined that the calculated temperature T10 is equal to or lower than the predetermined temperature Ta, it is determined that the medium to be cooled is supercooled, the operation of the compressor 1 of the first unit is stopped (step S29), and the next step S30 is performed. Proceed to

  On the other hand, if the calculation temperature T10 is higher than the predetermined temperature Ta in the determination in step S28, it is determined whether T11 is equal to or lower than the predetermined temperature Ta (step S30). Here, when it is determined that the calculated temperature T11 is equal to or lower than the predetermined temperature Ta, it is determined that the medium to be cooled is supercooled, the operation of the compressor 1 of the second machine is stopped (step S31), and step S21 is performed again. Judge by Note that if the calculation temperature T11 is equal to or higher than the predetermined temperature Ta in the determination in step S30, the determination is made again from the same step S21.

  As described above, according to the present embodiment, for example, even in the use side heat exchanger 4 where it is difficult to detect the cold water outlet temperatures T10 and T11 on each unit side, the water refrigerant flowing into the use side heat exchanger 4 Without detecting T10 and T11 directly by detecting T6 at the inlet, T7 at the outlet from which the water refrigerant flows out of the use-side heat exchanger 4, and the operating capacity of the compressor of each refrigeration circuit These water temperatures can be easily estimated by calculation. Then, by adjusting the operation capacity of each compressor 1 and controlling the operation stop based on the estimated temperature, it is possible to prevent the medium to be cooled in the use side heat exchanger 4 from being frozen and the heat exchanger from being damaged thereby. can do.

  Moreover, according to this embodiment, since it is not necessary to install the thermistor for detecting the cold water exit temperature of each unit side, the manufacturing cost can be reduced correspondingly, which is economical.

(Second Embodiment)
Next, a second embodiment of the refrigeration apparatus of the present invention will be described with reference to the drawings. FIG. 2 is a refrigeration cycle system diagram showing an embodiment of a refrigeration apparatus to which the present invention is applied. FIG. 4 is a schematic view of the internal structure of the use side heat exchanger 4 of FIG. In the following description, the same reference numerals are used for the same components as those in the first embodiment, and duplicate descriptions are omitted.

  The refrigeration apparatus of this embodiment is different from the first embodiment in the configuration of the use side heat exchanger. In the use side heat exchanger 31 of the present embodiment, headers 32 and 33 are provided at one end on the opening side between the plates 8 and the other end opposite thereto. The header 32 includes independent headers 32a and 32b on the first machine 21 side and the second machine 22 side, and the header 33 includes independent headers 33a and 33b on the first machine 21 side and the second machine 22 side.

  The headers 32 a and 33 a and the headers 32 b and 33 b are communicated with each other via a water refrigerant channel between the plates 8. The headers 32a and 32b and the headers 33a and 33b are communicated in parallel via the water refrigerant channels 34 and 35, respectively. That is, in the use side heat exchanger 31 of the present embodiment, the refrigerant flow path and the water refrigerant flow path are both partitioned into the No. 1 machine 21 side and the No. 2 machine 22 side, and are in an independent relationship. Therefore, the flow of the refrigerant and the water refrigerant between the units is separated.

  Further, the thermistors 6 and 7 are respectively installed at the inlet portion before the water refrigerant flowing into the water refrigerant heat exchanger 31 is diverted to each unit side and at the outlet portion where the water refrigerant flows out from the use side heat exchanger 31. Has been.

  As in the first embodiment, the use-side heat exchanger 4 is configured so that the amount of water refrigerant (flow rate per unit time) flowing through the water refrigerant passages on the first and second units is the same. If the operating capacities of the compressors are the same, the refrigerant amounts (flow rates per unit time) flowing through the refrigerant flow paths are equal.

  In such a configuration of the use side heat exchanger 31, the water refrigerant that has flowed into the header 32 through the inlet is diverted through the water refrigerant flow path 34 to the water refrigerant flow paths on the first and second machines. After flowing in (solid arrow) and heat exchange, it flows into the header 33. In the header 33, the water refrigerant merged through the water refrigerant flow path 35 is discharged through the outlet. On the other hand, the refrigerant that has flowed in from the refrigerant introduction pipes 23 of the first machine 21 and the second machine 22 flows through the refrigerant flow path in the direction opposite to the water refrigerant (dotted arrow) and is discharged from the refrigerant discharge pipe 24, respectively. .

  Also in this embodiment, it is necessary to detect the chilled water outlet temperatures 10 and 11 at the outlet portions of the water refrigerant flow paths on each unit side, but each temperature is estimated on the assumption that a thermistor is not attached to these detection positions. To do. Here, when each compressor 1 operates and stops with the same capacity, T10 and 11 can be obtained by calculation using the control of FIG. 5 as in the first embodiment. When the capacity control function is installed in the compressor 1, T10 and 11 can be obtained by calculation using the control of FIG. In this way, in the usage-side heat exchanger 31 configured to distribute the water refrigerant in parallel with each unit and perform heat exchange, the water refrigerant can be prevented from freezing as in the first embodiment. .

  As described above, in the above-described embodiments, the refrigeration apparatus including two compressors (refrigeration circuits) is shown. However, the present invention is not limited to this, and more refrigeration circuits are mounted and their use. The same control can be performed in the configuration of the heat exchanger in which the side heat exchangers are connected in parallel.

  In the above embodiment, the flow rate of the water refrigerant flowing through the water refrigerant flow path on each unit side has been described as being the same. For example, even if the water refrigerant flow rate is different, the water refrigerant flow rate ratio on each unit side By detecting this, the same control can be performed.

1 is a refrigeration cycle system diagram illustrating a first embodiment of a refrigeration apparatus to which the present invention is applied. It is a refrigerating-cycle system | strain diagram which shows 2nd Embodiment of the freezing apparatus formed by applying this invention. It is the schematic of the internal structure of the utilization side heat exchanger of FIG. It is the schematic of the internal structure of the utilization side heat exchanger of FIG. It is a flowchart which shows the control operation at the time of combining several refrigeration circuits carrying the compressor which does not have a capacity | capacitance control function. It is a flowchart which shows the control operation at the time of using two refrigeration circuits which mount a capacity | capacitance control function in a compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Heat source side heat exchanger 3 Expansion apparatus 4 Use side heat exchanger 6,7 Thermistor 8 Plate 12 Control apparatus

Claims (5)

A compressor, a heat source side heat exchanger, an expansion device, and a plurality of refrigeration circuits that sequentially connect the use side heat exchanger to circulate the refrigerant are provided, and the medium to be cooled exchanged by each of the use side heat exchangers is used as a load. In the refrigeration equipment to be supplied,
Each of the use-side heat exchangers has a plurality of plates arranged opposite to each other, and alternately arranges a refrigerant flow path through which the refrigerant flows and a cooled medium flow path through which the cooled medium flows. A plate type heat exchanger is formed by communicating the cooling medium flow path of the utilization side heat exchanger on the entrance side and the exit side of the plate,
The detected temperature of the inlet side and outlet side of the medium to be cooled of the plate heat exchanger and the operating capacity of each refrigeration circuit are input to the outlet side of the cooling medium flow path of each user side heat exchanger. A refrigeration apparatus comprising temperature estimation means for estimating the temperature of the medium to be cooled by calculation. A compressor, a heat source side heat exchanger, an expansion device, a plurality of refrigeration circuits that sequentially connect the use side heat exchanger to circulate the refrigerant, and a medium to be cooled exchanged by each of the use side heat exchangers as a load In the refrigeration equipment to be supplied,
Each of the use-side heat exchangers is configured by alternately arranging a plurality of plates facing each other and a refrigerant flow path through which the refrigerant flows and a cooled medium flow path through which the cooled medium flows, A plate-type heat exchanger is formed by arranging a pair of common headers that allow the cooling medium flow paths at both ends of the plate of the use side heat exchanger to communicate with each other;
The detected temperature of the inlet side and outlet side of the medium to be cooled of the plate heat exchanger and the operating capacity of each refrigeration circuit are input to the outlet side of the cooling medium flow path of each user side heat exchanger. A refrigeration apparatus comprising temperature estimation means for estimating the temperature of the medium to be cooled by calculation. A compressor, a heat source side heat exchanger, an expansion device, a plurality of refrigeration circuits that sequentially connect the use side heat exchanger to circulate the refrigerant, and a medium to be cooled exchanged by each of the use side heat exchangers as a load In the refrigeration equipment to be supplied,
Each usage-side heat exchanger has a plurality of plates arranged opposite to each other, alternately arranged refrigerant flow paths through which the refrigerant flows and cooled medium flow paths through which the cooled medium flows, and The cooling medium flow path at both ends of the plate is communicated with each other by a pair of headers, and a plate heat exchanger is formed in which the headers of all the use side heat exchangers are communicated with each other.
The detected temperature of the inlet side and outlet side of the medium to be cooled of the plate heat exchanger and the operating capacity of each refrigeration circuit are input to the outlet side of the cooling medium flow path of each user side heat exchanger. A refrigeration apparatus comprising temperature estimation means for estimating the temperature of the medium to be cooled by calculation. The said temperature estimation means has a control means to change the operation capacity of the said refrigerating circuit based on the said estimated value, when the estimated value of the said to-be-cooled medium temperature is below setting temperature, The Claim 1 thru | or 3 characterized by the above-mentioned. The refrigeration apparatus according to any one of the above. The refrigeration according to any one of claims 1 to 3, wherein the temperature estimation means includes control means for stopping the operation of the refrigeration circuit when the estimated value of the temperature of the cooling medium is equal to or lower than a set temperature. apparatus.

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