JP2009236392A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner can prevent freezing of water in a chiller device and perform smooth air conditioning, in the air conditioner in which direct expansion indoor units and the chiller device are connected to an outdoor unit in parallel. <P>SOLUTION: The direct expansion indoor units 11a, 11b and the chiller device 12 are connected to the outdoor unit 10 in parallel via refrigerant piping 9. The direct expansion indoor units 11a, 11b have a first function to order stop of their operation when the temperature of a refrigerant reaches a freezing temperature of drain. The chiller device 12 has the first function and a second function to order stop of its operation when the temperature of cold water or the temperature of a plate heat exchanger 32 reaches a water freezing estimated temperature. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an air conditioner in which a direct expansion indoor unit and a chiller device are connected in parallel to an outdoor unit via a refrigerant pipe.

Generally, what connected the chiller apparatus to the outdoor unit via refrigerant | coolant piping is known (for example, refer patent document 1). For example, a plate heat exchanger is mounted on the chiller device, and a water pipe is connected to the plate heat exchanger, and water supplied to the water pipe is cooled or heated by a refrigerant to generate cold water or hot water. Has been.
Although this heat exchanger has good heat exchange efficiency, when water circulating inside freezes, it is necessary to thermo-off itself in order to eliminate this freezing. Conventionally, in the chiller device, the chiller device is thermo-off when the refrigerant temperature reaches, for example, minus 10 ° C.
JP 2004-251486 A

By the way, when the chiller device is connected to the outdoor unit as described above, and when one or a plurality of directly expanded indoor units are connected in parallel with the chiller device, the directly expanded indoor unit is an individual air conditioner, and there is a space to be conditioned. Since it is not uniform and the thermostat of the direct expansion indoor unit is repeatedly turned on and off in the relationship between the room temperature and the set temperature, a sudden load fluctuation may occur.
In the above configuration, when the load of the directly expanded indoor unit fluctuates rapidly, excessive refrigerant flows into the chiller device, the refrigerant temperature temporarily reaches, for example, minus 10 ° C., and the chiller device may be immediately thermo-off. . This phenomenon is a frequent transient phenomenon, and there is a problem that smooth cold / hot water cannot be generated if the chiller device is thermo-off each time.

  Further, in the above configuration, if the load requirement of the chiller device is large, the circulation amount of the refrigerant increases even if the load of the direct expansion indoor unit is small. In this case, when a large amount of refrigerant flows into the directly expanded indoor unit, the drain freezes between the heat exchanger fins of the directly expanded indoor unit, and the air volume is reduced, thereby causing a problem that smooth air conditioning cannot be performed.

  Therefore, an object of the present invention is to provide an air conditioner that can prevent freezing of water in a chiller device and can perform smooth air conditioning in an air conditioner in which a direct expansion indoor unit and a chiller device are connected in parallel to an outdoor unit. There is.

The present invention relates to an air conditioner, wherein a direct expansion indoor unit and a chiller device are connected in parallel to an outdoor unit via a refrigerant pipe, and the direct expansion indoor unit has a temperature of the refrigerant reaching a freezing temperature of the drain. The chiller device has a first function for instructing its own operation stop, and the chiller device is configured to perform its own function when the temperature of the chilled water or the temperature of the heat exchanger reaches the estimated freezing temperature of the water. And a second function for instructing operation stop.
In the present invention, the direct expansion indoor unit and the chiller device have a refrigerant temperature that causes drain icing between the fins of the heat exchanger of the direct expansion indoor unit (for example, the refrigerant) If the temperature is kept at 10 [deg.] C. for 2 minutes or less), the operation is stopped. Here, the temperature of the refrigerant that causes the freezing of the drain of the heat exchanger of the direct expansion indoor unit can be effectively used as the temperature of the refrigerant that causes the freezing of the cold water in the chiller device. Therefore, according to the above configuration, drainage can be prevented from freezing in the directly expanded indoor unit, and cold water can be prevented from freezing in the chiller device.
Further, in addition to the above function, the chiller device instructs the stop when the temperature of the cold water flowing through itself or the temperature of its own heat exchanger reaches the estimated freezing temperature of the water. Freezing can be prevented.

Here, in the air conditioner of the present invention, a water circulation pump to the chiller device is provided, and when the temperature of the outside air reaches the assumed freezing temperature of water during the operation stop of the chiller device, A third function for instructing the start of operation may be provided.
According to this configuration, it is possible to prevent cold water from being frozen by outside air.

  According to the present invention, in an air conditioner in which a direct expansion indoor unit and a chiller device are connected in parallel to an outdoor unit, freezing of the drain of the heat exchanger of the direct expansion indoor unit is prevented and smooth air conditioning is achieved. In addition, it is possible to prevent freezing of the chiller water.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram schematically illustrating a configuration of an air conditioner 1 according to the present embodiment. As shown in this figure, the air conditioner 1 includes an outdoor unit 10, and two directly-expanded indoor units 11 a and 11 b and a chiller device 12 are arranged in parallel to the outdoor unit 10 through a refrigerant pipe 9. It is connected to the. In FIG. 1, the direct expansion indoor units 11 a and 11 b are in a cooling operation and the chiller device 12 is generating a cold water, and the following explanation is also given for the air conditioner 1 in this state. Will be described.

As shown in FIG. 1, the outdoor unit 10 includes an accumulator 15 that separates the refrigerant into a gas and a liquid and derives only the gas, a compressor 16 that derives the refrigerant sucked from the accumulator 15 at a high temperature and a high pressure, A four-way valve 17 that is connected to the compressor 16 and changes the refrigerant circuit by cooling operation and heating operation, and outdoor heat that exchanges heat between the refrigerant and air derived from the compressor 16 and liquefies and derives the refrigerant. And an exchanger 18. The outdoor heat exchanger 18 includes fins 19, and the fins 19 improve the efficiency of heat exchange between the refrigerant and air.
The outdoor unit 10 includes an outdoor control unit 20 that controls each device included in the outdoor unit 10. The outdoor control unit 20 is communicably connected to indoor control units 21a and 21b and a chiller control unit 22 which will be described later. These control units cooperate with each other, for example, to adjust the drive level of the compressor 16 or the like. It is the structure which controls the harmonic machine 1 whole.

The direct expansion indoor unit 11a includes an on-off valve 232a that controls the introduction or shut-off of the refrigerant to itself by opening and closing the valve, an expansion valve 24a that decompresses the refrigerant led out by the outdoor heat exchanger 18 into a low-temperature and low-pressure liquid, An indoor heat exchanger 25a that cools the air by evaporating the refrigerant derived from the expansion valve 24a at a predetermined temperature is provided. As shown in FIG. 1, the indoor heat exchanger 25a includes fins 26a, and the fins 26a improve the efficiency of heat exchange between the refrigerant and the air. In addition, although the direct expansion indoor unit 11a is provided with the on-off valve 232a, the on-off valve 232a is operated at the time of heating operation to block introduction of the refrigerant to itself, for example.
Indoor refrigerant temperature sensors 27a and 28a for detecting the temperature of the refrigerant are provided in the vicinity of the indoor heat exchanger 25a, and the refrigerant introduced into the indoor heat exchanger 25a by the indoor refrigerant temperature sensors 27a and 28a is provided. The temperature can be detected.

The direct expansion indoor unit 11a includes an indoor control unit 21a that controls each device included in the direct expansion indoor unit 11a. The indoor control unit 21a and the indoor refrigerant temperature sensors 27a and 28a described above are communicably connected to each other, and the indoor control unit 21a performs the indoor heat exchanger 25a based on the output values of the indoor refrigerant temperature sensors 27a and 28a. The temperature of the refrigerant introduced into is detected. Further, as described above, the indoor control unit 21a and the outdoor control unit 20 are communicably connected, and the indoor control unit 21a outputs, for example, a signal indicating the detected refrigerant temperature to the outdoor control unit 20. Or a signal indicating its own state such as the open / close state of the on-off valve 232a can be output to the outdoor control unit 20.
The indoor control unit 21a includes a time measuring unit 29a that performs various time measuring operations based on a reference clock generated by an oscillator (not shown).

  Here, the direct expansion indoor unit 11a includes the fins 26a, but when the drain adhering to the fins 26a is frozen during cooling operation, the frozen drain inhibits the air flowing through the fins 26a. Efficient heat exchange is hindered. In order to prevent this, the indoor control unit 21a according to the present embodiment performs the following control. That is, when the temperature of the refrigerant detected by the indoor refrigerant temperature sensor 28a continues below the temperature that may cause drain icing (“2 ° C.” in the present embodiment) for 10 minutes, If this state continues any further, it is considered that drain icing may occur. Therefore, the expansion valve 24a is closed and the introduction of the refrigerant is shut off (hereinafter, the expansion valve is closed and the introduction of the refrigerant is cut off). (Referred to as “thermo-off”), the drain adhering to the fins 26a is prevented from further cooling, and the freezing of the drain is prevented. In the following description, the function of the direct expansion indoor unit 11a to be thermo-off when the temperature of the refrigerant reaches a temperature at which the freezing temperature of the drain is generated is referred to as “first function”.

As described above, in the first function, when the direct expansion indoor unit 11a determines whether to thermo-off in order to prevent drain icing in the first function, not only the temperature of the refrigerant but also the temperature of the refrigerant continues for a predetermined time. This is for the following reason. When the thermo-off is determined only by the temperature of the refrigerant (for example, when the thermo-off is performed when the temperature of the refrigerant becomes 2 ° C. or lower), although drain icing can be surely prevented, there is a problem that the thermo-off frequently occurs. This is because the size of the conditioned room in which the directly expanded indoor unit 11a is installed is not uniform, and the set temperature of the conditioned room is changed by the user each time. The air conditioning load often increases rapidly. Further, when the air conditioning load increases, the amount of refrigerant introduced into the directly expanded indoor unit 11a is increased by increasing the drive level of the compressor 16 of the outdoor unit 10, but at this time, temporarily This is because the temperature of the refrigerant introduced into the indoor heat exchanger 25a may be 2 ° C. or lower. In addition, if the demand for the load of the chiller device 12 connected in parallel to the outdoor unit 10 is large, the circulation amount of the refrigerant increases even if the load of the direct expansion indoor unit 11a is small. In this case, a large amount of refrigerant flows into the directly expanded indoor unit, and the temperature of the refrigerant temporarily introduced into the indoor heat exchanger 25a may be 2 ° C. or lower.
In view of this, in this embodiment, even if the temperature of the refrigerant is 2 ° C. or lower, if this state does not continue for 10 minutes or more, the possibility that the drain has reached freezing is extremely low. The thermo-off is performed only when the temperature lasts for 10 minutes at a temperature of 2 ° C. or lower, thereby preventing the freezing of the drain and preventing frequent occurrence of the thermo-off, thereby realizing smooth air conditioning.

  The direct expansion indoor unit 11b has substantially the same configuration as the direct expansion indoor unit 11a, and includes an indoor control unit 21b, an on-off valve 232b, an expansion valve 24b, an indoor heat exchanger 25b, fins 26b, and an indoor refrigerant temperature sensor 28b. Etc.

  On the other hand, the chiller device 12 includes an on-off valve 302 that controls introduction or shut-off of the refrigerant to itself by opening and closing of the valve, an expansion valve 31 that depressurizes the refrigerant led out by the outdoor heat exchanger 18 and turns it into a low-temperature low-pressure liquid, The plate heat exchanger 32 that exchanges heat between the refrigerant derived from the expansion valve 31 and water to generate cold water (hot water when the direct expansion indoor unit is in a heating operation), and the plate heat exchange The water pipe 35 includes an outward pipe 33 through which the aqueous medium flowing into the vessel 32 flows and a return pipe 34 through which the aqueous medium flowing out from the plate heat exchanger 32 flows. A circulation pump 36 for causing the aqueous medium to flow in the water pipe 35 is provided in the forward pipe 33 of the water pipe 35. The circulation pump 36 is communicably connected to a chiller control unit 22 (described later), and is controlled by the chiller control unit 22 or under the control of the outdoor control unit 20 connected to the chiller control unit 22. The start and stop of the drive are executed. In addition, although the chiller apparatus 12 is provided with the on-off valve 302, the on-off valve 302 act | operates at the time of heating operation, for example, has become the structure which interrupts | blocks introduction of the refrigerant | coolant to self.

  Further, chiller refrigerant temperature sensors 37 and 38 for detecting the temperature of the refrigerant are provided in the vicinity of the plate heat exchanger 32, and are introduced into the plate heat exchanger 32 by the chiller refrigerant temperature sensors 37 and 38. The temperature of the refrigerant to be detected can be detected. Further, chiller water medium temperature sensors 39 and 40 for detecting the temperature of the aqueous medium are provided in the vicinity of the plate heat exchanger 32, and the plate type heat exchange is performed by the chiller aqueous medium temperature sensors 39 and 40. The temperature of the aqueous medium flowing out from the vessel 32 can be detected. A heat exchanger temperature sensor 41 is provided on the surface of the plate heat exchanger 32, and the temperature of the surface of the plate heat exchanger 32 can be detected by the heat exchanger temperature sensor 41. It has become.

In addition, the chiller device 12 includes a chiller control unit 22 that controls each device included in the chiller device 12. The chiller control unit 22 and the above-described chiller refrigerant temperature sensors 37 and 38, the chiller aqueous medium temperature sensors 39 and 40, and the heat exchanger temperature sensor 41 are connected so as to be capable of signal communication. 21a indicates the temperature of the refrigerant introduced into the plate heat exchanger 32, the temperature of the aqueous medium flowing out from the plate heat exchanger 32, and the surface of the plate heat exchanger 32 based on the output value of each sensor. Detect the temperature. In addition, as described above, the chiller control unit 22 and the outdoor control unit 20 are communicably connected, and the chiller control unit 22 includes a signal indicating the detected refrigerant temperature, an open / close state of the on-off valve 302, and the like. A signal indicating its own state can be transmitted to the outdoor control unit 20.
The chiller control unit 22 includes a time measuring unit 42 that performs various time measuring operations based on a reference clock generated by an oscillator (not shown).

Here, unlike the direct expansion indoor units 11a and 11b, the chiller device 12 includes a water pipe 35. When the cold medium is generated, if the aqueous medium flowing through the water pipe 35 is excessively cooled and frozen, the water pipe 35 and the circulation pump 36 may be damaged. . In order to prevent this, the chiller control unit 22 according to the present embodiment performs thermo-off when any of the three conditions of the first condition, the second condition, and the third condition described below is satisfied. This prevents the aqueous medium from freezing and prevents damage to the water pipe 35 and the pump.
That is, the chiller control unit 22 detects the temperature of the aqueous medium detected by the chiller aqueous medium temperature sensors 39 and 40 when the temperature is lower than the temperature (“2 ° C.” in the present embodiment) at which there is a possibility of freezing (first condition). ) If the aqueous medium is further cooled, the aqueous medium may freeze. Therefore, thermo-off is performed, and further cooling of the aqueous medium is stopped to prevent the aqueous medium from freezing. In the present embodiment, the chiller aqueous medium temperature sensor 40 is provided on the outlet side of the plate heat exchanger 32. Here, freezing of the aqueous medium excessively cooled by the plate heat exchanger 32 starts sequentially from the aqueous medium flowing out from the plate heat exchanger 32, but the chiller aqueous medium temperature sensor 40 Since it is provided on the outlet side of the heat exchanger 32, it is possible to quickly detect freezing of the aqueous medium.
In addition, the chiller control unit 22 has a temperature of the plate heat exchanger 32 detected by the heat exchanger temperature sensor 41 that is equal to or lower than a temperature at which the aqueous medium is frozen (“2 ° C.” in this embodiment) ( (Second condition) Since the aqueous medium cooled in the plate heat exchanger 32 may be frozen, the thermo-off is performed, and further cooling of the aqueous medium is stopped to prevent the aqueous medium from freezing. In the following description, based on the first condition and the second condition described above, the temperature of the aqueous medium or the temperature of the heat exchanger is set to a temperature at which the aqueous medium is frozen (assumed freezing temperature). The function to turn off the thermo when it arrives is called the second function.

Further, in addition to the above conditions, the chiller control unit 22 causes the conditions similar to those of the direct expansion indoor units 11a and 11b, that is, the refrigerant temperature detected by the chiller refrigerant temperature sensors 37 and 38 to freeze the aqueous medium. The thermo-off is also executed when the temperature is kept below 10 minutes (third condition) in a state where the temperature is below a certain temperature (“2 ° C.” in the present embodiment). That is, the chiller device 12 also has the first function described above. As described above, the chiller control unit 22 includes the first condition that is a condition related to the temperature of the aqueous medium, the second condition that is a condition related to the temperature of the plate heat exchanger 32, and the first condition that is related to the temperature of the refrigerant. When any one of the three conditions is satisfied, the thermo-off is executed to ensure the prevention of freezing of the aqueous medium.
Here, in the present embodiment, the third condition, which is the same condition as that of the directly expanded indoor units 11a and 11b, is applied to the condition relating to the temperature of the refrigerant. By doing so, the following effects can be achieved. it can.

  That is, in the case of a refrigeration apparatus in which the directly expanded indoor units 11a and 11b do not exist and the outdoor unit 10 and the chiller unit 12 are connected one-on-one, the temperature of the refrigerant is changed to water instead of the third condition. It is possible to apply a condition (hereinafter referred to as “temporary condition”) in which the thermo-off is performed when a temperature (for example, minus 10 ° C.) at which the medium is surely frozen is reached. If this condition is applied, it is possible to prevent the aqueous medium from freezing due to the temperature of the refrigerant. However, in the air conditioner 1 in which the directly expanded indoor units 11a and 11b and the chiller device 12 are connected in parallel to the outdoor unit 10 as in the present embodiment, the air conditioning load state of the directly expanded indoor units 11a and 11b In addition, due to the thermo-on / thermo-off state, the temperature of the refrigerant of the chiller device 12 sometimes temporarily reaches minus 10 ° C. or less, and the above temporary condition is applied as a condition relating to the temperature of the refrigerant. In this case, a situation occurs in which the chiller device 12 is thermo-off each time.

  Specifically, when a set temperature that is far away from the current temperature of the conditioned room in which the direct expansion indoor unit 11a is installed is set for the direct expansion indoor unit 11a, the indoor control unit 21a and the outdoor control unit Under the control of 20, the drive level of the compressor 16 rises, and a large amount of refrigerant is introduced into the indoor heat exchanger 25a of the direct expansion indoor unit 11a. At this time, a large amount of refrigerant is also introduced into the chiller device 12 connected in parallel to the outdoor unit 10, and the temperature of the refrigerant in the chiller device 12 may temporarily reach −10 ° C. or less. In addition, when the temperature of the conditioned room in which the directly expanded indoor unit 11a is installed reaches a desired set temperature, or when the cooling operation is stopped by a user instruction or the like, the directly expanded indoor unit 11a is thermo-off. However, in this case, the refrigerant to be introduced into the direct expansion indoor unit 11a is introduced into the chiller device 12 connected in parallel to the outdoor unit 10, The temperature of the refrigerant in the chiller device 12 may temporarily reach minus 10 ° C. or lower.

  In view of this, in the present embodiment, due to the state of the directly expanded indoor units 11a and 11b, the temperature of the refrigerant of the chiller device 12 temporarily becomes minus 10 ° C. or less, and the directly expanded indoor units 11a and 11b are frequently thermo-off. In order to prevent such a situation, the third condition that is the same as the condition applied to the directly expanded indoor units 11a and 11b is applied to the condition relating to the temperature of the refrigerant instead of the provisional condition described above. As described above, in the directly expanded indoor units 11a and 11b, the third condition is applied to prevent the freezing of the drain. However, the drain and the aqueous medium are the same water, and the temperature differs from that to the freezing or freezing. Therefore, the third condition can be effectively used as a condition for preventing the freezing of the aqueous medium in place of the freezing of the drain. Furthermore, as described above, the direct expansion indoor units 11a and 11b determine whether or not the refrigerant temperature has continued for a predetermined time in the third condition, thereby preventing frequent thermo-off. However, by applying the third condition in the chiller device 12, it is possible to prevent the thermo-off from occurring frequently as well.

  In addition, the chiller device 12 of the air conditioner 1 according to the present embodiment includes an outside air temperature sensor 45 for measuring the temperature of the outside air. The outside air temperature sensor 45 is communicably connected to the chiller control unit 22, and the chiller control unit 22 can detect the temperature of the outside air based on the output value of the outside air temperature sensor 45. The temperature of the outside air detected by the outside air temperature sensor 45 is a temperature that causes the aqueous medium in the water pipe 35 to freeze (in this embodiment, “2 ° C.”), and the chiller device 12 is operated. When the circulating pump 36 is not driven, the chiller control unit 22 sends a driving signal to the circulating pump 36 and starts driving the circulating pump 36. Thereby, an aqueous medium flows in the water piping 35, and freezing of the aqueous medium in the water piping 35 by external air is prevented. In the following description, the function of starting the circulation pump 36 when the temperature of the outside air reaches a temperature causing freezing of the aqueous medium while the operation of the chiller device 12 is stopped is referred to as “third. Called "functions".

Next, the operation of the chiller device 12 when generating cold water will be described with reference to the flowchart of FIG.
First, in step SA1, the chiller controller 22 of the chiller device 12 determines whether or not the chiller device 12 is currently in operation, that is, whether or not the circulating pump 36 is driven to circulate the aqueous medium and generate cold water. Determine. When the chiller device 12 is not in operation (step SA1: NO), the chiller control unit 22 determines the temperature at which the temperature of the outside air causes the aqueous medium in the water pipe 35 to freeze based on the output value of the outside air temperature sensor 45. It is determined whether it is below (in this embodiment "2 degreeC") (step SA2). When the temperature of the outside air is not lower than 2 ° C. (step SA2: NO), the chiller control unit 22 returns the processing procedure to step SA1. When the temperature of the outside air is below 2 ° C. (step SA2: YES), the chiller control unit 22 transmits a drive signal to the circulation pump 36 in order to prevent the aqueous medium in the water pipe 35 from being frozen by the outside air, Driving of the circulation pump 36 is started (step SA3). Thereafter, the chiller control unit 22 monitors whether or not the outside air temperature is below 2 ° C. (step SA4), and when the outside air temperature exceeds 2 ° C. (step SA4: NO), the circulation pump 36 is driven. Is stopped (step SA10). After stopping the driving of the circulation pump 36, the chiller control unit 22 returns the processing procedure to Step SA1.

  On the other hand, when the chiller device 12 is operating in step SA1 (step SA1: YES), the chiller control unit 22 determines whether or not the first condition described above is satisfied, that is, the temperature of the aqueous medium may be frozen. It is determined whether or not a certain temperature (in this embodiment, “2 ° C.”) has been reached (step SA6). When the temperature of the aqueous medium is lower than 2 ° C. (step SA6: YES), the chiller control unit 22 shifts the processing procedure to step SA7 in order to prevent the aqueous medium from freezing. When the temperature of the aqueous medium is not lower than 2 ° C. (step SA6: NO), the chiller control unit 22 determines whether or not the second condition is satisfied, that is, the temperature of the plate heat exchanger 32 is frozen of the aqueous medium. It is determined whether or not the temperature is lower than the temperature (in this embodiment, “2 ° C.”) (step SA8). When the temperature of the plate heat exchanger 32 is lower than 2 ° C. (step SA8: YES), the chiller control unit 22 shifts the processing procedure to step SA7 in order to prevent the aqueous medium from freezing. When the temperature of the plate heat exchanger 32 is not lower than 2 ° C. (step SA8: NO), the chiller control unit 22 determines whether or not the third condition is satisfied, that is, freezes the aqueous medium with respect to the temperature of the refrigerant. It is determined whether or not the state of lowering the temperature (“2 ° C.” in the present embodiment) that occurs is continued for 10 minutes (step SA9). When the state where the temperature of the refrigerant is lower than 2 ° C. continues for 10 minutes (step SA9: YES), the chiller control unit 22 shifts the processing procedure to step SA7 in order to prevent the aqueous medium from freezing. If the temperature of the aqueous medium is less than 2 ° C. for 10 minutes (step SA9: NO), the chiller control unit 22 returns the processing procedure to step SA1, and again determines whether the aqueous medium is frozen. .

In step SA7, the chiller control unit 22 performs thermo-off to prevent freezing of the aqueous medium, stops further cooling of the aqueous medium, and prevents freezing of the aqueous medium. And the chiller control part 22 stops the drive of the pump in order to prevent that the circulation pump 36 operates in the state which the aqueous medium frozen, and the circulation pump 36 and the water piping 35 resulting from this are damaged ( Step SA10). Thereafter, the chiller control unit 22 outputs a signal indicating the temperature of the aqueous medium, the temperature of the plate heat exchanger, the temperature of the refrigerant, and the driving state of the circulation pump 36 to the outdoor control unit 20. Based on this signal, the outdoor control unit 20 can drive the compressor 16 and control the direct expansion indoor units 11a and 11b.
Next, the chiller control unit 22 determines whether or not any of the first, second, and third conditions is satisfied. Specifically, the temperature of the aqueous medium exceeds 2 ° C., and the plate type heat exchange is performed. It is monitored whether the thermo-on is possible by monitoring whether the temperature of the vessel 32 exceeds 2 ° C. and whether the temperature of the refrigerant exceeds 2 ° C. (step SA12). When the thermo-ON is possible (step SA12: YES), the chiller control unit 22 performs thermo-ON (step SA13), starts driving the circulation pump 36 (step SA14), and starts generating cold water again. The chiller control unit 22 outputs a signal indicating the temperature of the aqueous medium, the temperature of the plate heat exchanger, the temperature of the refrigerant, and the driving state of the circulation pump 36 to the outdoor control unit 20. Based on this signal, the outdoor control unit 20 can drive the compressor 16 and control the direct expansion indoor units 11a and 11b.

As described above, according to the present embodiment, the directly expanded indoor units 11a and 11b are turned off when the temperature of the refrigerant reaches a temperature at which the freezing temperature of the drain is generated. The first function, which is the function to be performed, is provided. The chiller device 12 has this first function, and a function for thermo-off when the temperature of the aqueous medium or the temperature of the heat exchanger reaches a temperature at which the aqueous medium is frozen (assumed freezing temperature). It has the second function.
Due to this configuration, drain freezing can be prevented in the direct expansion indoor units 11a and 11b, a reduction in air volume can be prevented, and smooth air conditioning can be performed. Furthermore, since the conditions for preventing the freezing of the drain can be effectively used as the conditions for preventing the freezing of the aqueous medium, the freezing of the aqueous medium can be prevented in the chiller device 12 by the first function. Furthermore, freezing of the aqueous medium in the chiller device 12 can be prevented by the second function.
In the present embodiment, the chiller device 12 has a function of starting to drive the circulation pump 36 when the temperature of the outside air reaches a temperature at which the aqueous medium is frozen while the operation of the chiller device 12 is stopped. It has a third function. For this reason, it can prevent that cold water freezes with external air.

The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention.
In the present embodiment, the chiller control unit 22 is configured to control the circulation pump 36, determine whether the chiller device 12 is thermo-off, and the like, but this is an outdoor connected to the chiller control unit 22 in a communicable manner. The structure which the control part 20 performs may be sufficient.

It is a figure which shows typically the structure of the air conditioner which concerns on this embodiment. It is a flowchart which shows operation | movement of the chiller apparatus at the time of cold water production | generation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioner 9 Refrigerant piping 10 Outdoor unit 11a Direct expansion indoor unit 11b Direct expansion indoor unit 12 Chiller device 32 Plate type heat exchanger 36 Circulation pump

Claims (2)

A direct expansion indoor unit and a chiller device are connected in parallel to the outdoor unit via a refrigerant pipe,
The direct expansion indoor unit has a first function of commanding its own operation stop when the temperature of the refrigerant reaches the freezing temperature of the drain,
The chiller device has the first function and a second function for instructing to stop the operation when the temperature of the cold water or the temperature of the heat exchanger reaches the estimated freezing temperature of the water. A featured air conditioner.   A water circulation pump to the chiller device is provided, and a third function is provided for instructing the start of operation of the circulation pump when the temperature of the outside air reaches the water freezing estimated temperature while the operation of the chiller device is stopped. The air conditioner according to claim 1.

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