JPWO2018066089A1 - Refrigerator and air conditioning system - Google Patents

Abstract

The refrigerator (2) includes a first heat exchanger (21) that performs heat exchange between the refrigerant circuit and the first circulating water circulating between the cooling tower and the refrigerant circulating in the refrigerant circuit, and the air conditioner (3). A second heat exchanger (23) for exchanging heat between the second circulating water circulating between the refrigerant and the refrigerant. In the refrigerator (2), in the first flow path, all of the first circulating water passes through the first heat exchanger (21), and in the second flow path, all of the first circulating water is in the air conditioner (3). In the third flow path, a part of the first circulating water passes through the first heat exchanger (21), and the remainder of the first circulating water is mixed with the second circulating water. The three-way valve (24, 25) switches the flow path of the first circulating water to any one of the first flow path, the second flow path, and the third flow path.

Description

  The present invention relates to a refrigerator and an air conditioning system.

  Cooling water is cooled by cooling water from a cooling tower, and air conditioning is performed by exchanging heat between the cooling water and air. Under certain conditions, the cooling water is supplied to a load device such as an air conditioner without operating a refrigerator. There is known a technique called free cooling that is supplied to the vehicle.

  Since free cooling is a condition that the outside air temperature is low, its use period is limited. Therefore, a technique for extending the use period of free cooling has been proposed.

  For example, Patent Document 1 includes a pre-cooling heat exchanger that exchanges heat with cooling water that is circulated between a cooling tower and a load-side heat medium that is sent to the refrigerator, and performs cooling in parallel with the operation of the refrigerator. A configuration in which the load-side heat medium is cooled by a pre-cooling heat exchanger is disclosed.

JP 2004-132651 A

  However, in the above technique, the pre-cooling heat exchanger is provided outside the refrigerator, so that the water circuit becomes complicated and heat exchange loss occurs.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a refrigerator or the like capable of extending an air conditioning period using free cooling without depending on a complicated configuration.

In order to achieve the above object, a refrigerator according to the present invention includes:
A refrigerant circuit;
A first heat exchanger for exchanging heat between the first circulating water circulating between the cooling tower and the refrigerant circulating in the refrigerant circuit;
A second heat exchanger that exchanges heat between the second circulating water circulating between the load device and the refrigerant;
A first flow path through which all of the first circulating water passes through the first heat exchanger;
A second flow path through which all of the first circulating water passes through the load device;
A third flow path in which a portion of the first circulating water passes through the first heat exchanger and the remainder of the first circulating water mixes with the second circulating water;
A refrigerator comprising: switching means for switching the flow path of the first circulating water to any one of the first flow path, the second flow path, and the third flow path.

  According to the present invention, a part of the first circulating water that circulates between the refrigerator and the cooling tower passes through the first heat exchanger, and the remainder of the first circulating water circulates with the load device. Since the third flow path to be mixed with the second circulating water is provided, the air conditioning period using free cooling can be extended without depending on a complicated configuration.

The figure which shows the structure of the air conditioning system which concerns on embodiment of this invention. Block diagram showing the configuration of the refrigerator Diagram for explaining the flow path of the cooling water in the normal mode The figure for demonstrating the flow path of the cooling water at the time of the 1st free cooling mode The figure for demonstrating the flow path of the cooling water at the time of 2nd free cooling mode Block diagram showing the configuration of the air conditioner Block diagram showing the hardware configuration of the control device Diagram showing the functional configuration of the control device Flow chart showing the procedure of air conditioning control processing The block diagram which shows the structure of the refrigerator in other embodiment. The block diagram which shows the structure of the refrigerator in other embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of an air conditioning system according to an embodiment of the present invention. This air conditioning system is a system that performs air conditioning of factories, office buildings, apartment houses, and the like, and includes a cooling tower 1, a refrigerator 2, an air conditioner 3, and a control device 4.

  The cooling tower 1 is connected to the refrigerator 2 via the pipe 7 and cools the cooling water (first circulating water) that circulates between the refrigerator 2 via the pipe 7. The cooling tower 1 includes a fan (not shown) that supplies outside air to the inside, and employs a cooling system (sealed type) that exchanges heat by indirectly contacting the cooling water returned from the refrigerator 2 with the outside air. . The operation of the fan is controlled according to a command from the control device 4.

  The cooling water cooled by the cooling tower 1 is conveyed to the refrigerator 2 by the pump 5. The pump 5 includes an inverter circuit, and the drive rotational speed is changed in accordance with a command from the control device 4. Thereby, the flow volume of the cooling water conveyed to the refrigerator 2 can be changed.

The refrigerator 2 is connected to the cooling tower 1 via the pipe 7 as described above, connected to the air conditioner 3 via the pipe 8, and chilled water (circulated via the pipe 8 between the air conditioner 3 ( The second circulating water) is cooled. As shown in FIG. 2, the refrigerator 2 includes a compressor 20, a first heat exchanger 21, an expansion valve 22, a second heat exchanger 23, three-way valves 24 and 25, and a control board 26. Prepare. The compressor 20, the first heat exchanger 21, the expansion valve 22, and the second heat exchanger 23 are connected in a ring shape, and thereby a refrigerant circuit for circulating a refrigerant such as CO ₂ or HFC (hydrofluorocarbon) ( It is also called a refrigeration cycle circuit).

  The compressor 20 compresses the refrigerant to increase the temperature and pressure. The compressor 20 includes an inverter circuit that can change the capacity (the amount of delivery per unit) according to the drive frequency. The drive frequency of the compressor 20 is changed according to a command from the control board 26.

  The first heat exchanger 21 functions as a condenser, and performs heat exchange between the cooling water (first circulating water) supplied from the cooling tower 1 and the refrigerant discharged from the compressor 20, for example, plate type or two It is a heat exchanger such as a heavy pipe type.

  The expansion valve 22 expands the refrigerant sent from the first heat exchanger 21 to lower the temperature and pressure. The expansion valve 22 is, for example, an electronic expansion valve whose throttle opening can be adjusted by a stepping motor (not shown). In addition, as the expansion valve 22, a mechanical expansion valve, a capillary tube, or the like that employs a diaphragm for the pressure receiving portion may be used. The opening degree of the expansion valve 22 is changed according to a command from the control board 26.

  The second heat exchanger 23 is a plate-type or double-tube type heat exchanger, and performs heat exchange between the refrigerant sent from the expansion valve 22 and the cold water returned from the air conditioner 3. By this heat exchange, the refrigerant absorbs heat, evaporates, and phase transitions to refrigerant gas. On the other hand, cold water dissipates heat and the temperature drops. The cold water heat-exchanged by the second heat exchanger 23 is conveyed to the air conditioner 3 by the pump 6. The pump 6 includes an inverter circuit, and the driving rotational speed is changed according to a command from the control device 4.

  The three-way valves 24 and 25 (switching means) are well-known electric three-way valves for switching the flow path of the cooling water from the cooling tower 1, and each direction is in accordance with a command from the control board 26 (switching control means). The valve opening is adjusted. The refrigerator 2 is configured so that the first to third flow paths can be switched as the flow paths of the cooling water.

  As shown in FIG. 3, the first channel is a channel through which all the cooling water from the cooling tower 1 passes through the first heat exchanger 21, and in this case, the valves 24a and 24b in the three-way valve 24 are used. Is opened, and the valve 24c is closed. Further, the valve 25a in the three-way valve 25 is closed, and the valve 25b and the valve 25c are opened.

  As shown in FIG. 4, the second flow path is a flow path through which all the cooling water from the cooling tower 1 passes through the air conditioner 3. In this case, the valves 24a and 24c in the three-way valve 24 are opened. The valve 24b is closed. Further, the valves 25a and 25c in the three-way valve 25 are opened, and the valve 25b is closed.

  As shown in FIG. 5, the third flow path is a flow path through which cooling water from the cooling tower 1 passes through the first heat exchanger 21 and the air conditioner 3, and in this case, the valves 24 a to 24 in the three-way valve 24. 24c is opened, and the valves 25a to 25c in the three-way valve 25 are opened.

  The control board 26 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication interface, a readable / writable nonvolatile semiconductor memory, and the like (none of which are shown). The The control board 26 is communicably connected to the compressor 20, the expansion valve 22, and the three-way valves 24 and 25 via communication lines (not shown). Further, the control board 26 is connected to the control device 4 so as to be communicable by wire or wirelessly.

  The control board 26 controls each of the compressor 20, the expansion valve 22, and the three-way valves 24 and 25 in accordance with instructions from the control device 4.

  The air conditioner 3 (load device) is an air conditioner called a so-called fan coil unit, and adjusts the indoor air condition (temperature and humidity) by exchanging heat between the cold water from the refrigerator 2 and the indoor air. Do. As shown in FIG. 6, the air conditioner 3 includes a heat exchanger 30, a fan 31, and a control board 32.

  The heat exchanger 30 performs heat exchange between the cold water flowing from the refrigerator 2 and the indoor air. The fan 31 takes in (inhales) indoor air and sends the air after heat exchange into the room.

  The control board 32 includes a CPU, a ROM, a RAM, a communication interface, a readable / writable nonvolatile semiconductor memory, and the like (all not shown). The control board 32 is communicably connected to the control device 4 in a wired or wireless manner, and starts or stops driving the fan 31 according to a command from the control device 4.

  The control device 4 is a so-called air-conditioning remote controller installed in the vicinity of the entrance / exit of the room to be air-conditioned. As shown in FIG. 7, the CPU 40, the ROM 41, the RAM 42, the input device 43, the display 44, and the communication An interface 45 and a secondary storage device 46 are provided. These components are connected to each other via a bus 47. The CPU 40 comprehensively controls the control device 4. Details of the functions realized by the CPU 40 will be described later.

  The ROM 41 stores a plurality of firmware, data used when executing these firmware, and the like. The RAM 42 is used as a work area for the CPU 40. The input device 43 includes a push button, a touch panel, a touch pad, and the like, receives an operation by the user, and sends a signal related to the received operation to the CPU 40.

  The display 44 is a display device such as a liquid crystal display or an organic EL display, for example, and displays an operation screen related to indoor air conditioning, information about the indoor air condition (temperature, humidity), and the like under the control of the CPU 40. The communication interface 45 includes a network card for wireless communication or wired communication with the cooling tower fan, the control board 26 of the refrigerator 2, the control board 32 of the air conditioner 3, and the pumps 5 and 6.

  The secondary storage device 46 includes an EEPROM (Electrically Erasable Programmable Read-Only Memory), a readable / writable nonvolatile semiconductor memory such as a flash memory, and the like. The secondary storage device 46 stores one or more programs related to air conditioning control, data used when these programs are executed, and the like.

  Next, functions of the control device 4 will be described. Functionally, the control device 4 includes a user interface processing unit 400, a mode determination unit 401, and an air conditioning control unit 402, as shown in FIG. Each of these functional units is realized by the CPU 40 executing a program related to air conditioning control stored in the secondary storage device 46.

  The user interface processing unit 400 performs user interface processing via the input device 43 and the display 44. That is, the user interface processing unit 400 receives an operation from the user via the input device 43. In addition, the user interface processing unit 400 outputs information for presentation to the user on the display 44.

  The mode determination unit 401 determines the type of mode (cooling water use mode) when cooling water is used during the air conditioning operation. There are three types of cooling water use modes: a normal mode, a first free cooling mode, and a second free cooling mode. Among these modes, the mode determination unit 401 passes the outside air temperature, the target temperature, and the air conditioner 3. One mode is selected and determined based on the temperature or the like of the second circulating water returning to the refrigerator 2.

  The air conditioning control unit 402 controls each of the cooling tower 1, the refrigerator 2, the air conditioner 3, and the pumps 5 and 6 so that the indoor air temperature becomes a target temperature set by the user. In addition, the air conditioning control unit 402 instructs the control board 26 of the refrigerator 2 to switch to the flow path according to the type of the coolant usage mode determined by the mode determination unit 401.

  More specifically, when the type of the coolant usage mode determined by the mode determination unit 401 is the normal mode, the air conditioning control unit 402 instructs the control board 26 of the refrigerator 2 to switch to the first flow path. Further, when the type of the cooling water use mode determined by the mode determination unit 401 is the first free cooling mode, the air conditioning control unit 402 instructs the control board 26 of the refrigerator 2 to switch to the second flow path. When the type of the coolant usage mode determined by the mode determination unit 401 is the second free cooling mode, the air conditioning control unit 402 instructs the control board 26 of the refrigerator 2 to switch to the third flow path.

  Hereinafter, the state of the air conditioning system in each of the normal mode, the first free cooling mode, and the second free cooling mode will be described.

<Normal mode>
When the mode when using the cooling water is the normal mode, the refrigerator 2 has a first flow path through which all the cooling water from the cooling tower 1 passes through the first heat exchanger 21, as shown in FIG. Selected. In this case, the load Q generated in the heat exchanger 30 of the air conditioner 3, the heat amount Qe generated in the second heat exchanger 23, the heat amount Q_CT that the cooling water indirectly radiates to the atmosphere in the cooling tower 1, The relationship with the amount of heat Qc generated in one heat exchanger 21 is as follows.

  Q = Qe (Formula 1)

  Q_CT = Qc (Formula 2)

<First free cooling mode>
When the mode for using the cooling water is the first free cooling mode, the refrigerator 2 has a second flow path through which all the cooling water from the cooling tower 1 passes through the air conditioner 3 as shown in FIG. Selected. At this time, the control board 26 stops the operation of the compressor 20. In this case, the relationship among the load Q, the amount of heat Qe, the amount of heat Q_CT, and the amount of heat Qc is as follows.

  Q = Q_CT (Formula 3)

  Qe = Qc = 0 (Formula 4)

<Second free cooling mode>
When the mode for using the cooling water is the second free cooling mode, as shown in FIG. 5, the third flow path through which the cooling water from the cooling tower 1 passes through the first heat exchanger 21 and the air conditioner 3 is provided. Selected. In this case, the relationship among the load Q, the amount of heat Qe, the amount of heat Q_CT, and the amount of heat Qc is as follows.

  Q = Qe + Q_CT1 (Formula 5)

  Qc = Q_CT2 (Formula 6)

  Q_CT = Q_CT1 + Q_CT2 (Formula 7)

  Q_CT1 and Q_CT2 change by adjusting the valve opening degree of the three-way valves 24 and 25. That is, Q_CT2 decreases and Q_CT1 increases as the flow rate of the cooling water flowing into the first heat exchanger 21 decreases.

  FIG. 9 is a flowchart showing a procedure of air conditioning control processing executed by the control device 4. The air conditioning control process is started when the user performs an operation for starting the cooling operation via the input device 43, and is ended when the operation for stopping the operation is performed by the user.

  The mode determination unit 401 determines the type of the coolant usage mode (step S101). The air-conditioning control unit 402 instructs the refrigerator 2 to start operation and instructs switching to the flow path according to the type of the coolant usage mode determined by the mode determination unit 401 (step S102).

  In addition, the air conditioning control unit 402 instructs the cooling tower to start operation (step S103). Thereby, the fan of the cooling tower 1 starts driving.

  In addition, the air conditioning control unit 402 instructs the air conditioner 3 to start operation (step S104). Thereby, the fan 31 starts driving. The air conditioning control unit 402 operates the pumps 5 and 6.

  When a certain time (for example, 1 minute) elapses (step S105; YES), the mode determination unit 401 determines the type of the coolant usage mode (step S106). The air conditioning control unit 402 instructs the refrigerator 2 to switch to the flow path according to the type of the coolant usage mode determined by the mode determination unit 401 (step S107). The air-conditioning control unit 402 determines the type of the cooling water usage mode determined only when the type of the cooling water usage mode previously determined by the mode determination unit 401 is different from the type of the cooling water usage mode determined this time. Switching to the flow path according to the above may be instructed to the refrigerator 2.

  Although not described in FIG. 9, in the air conditioning control process, in addition to the switching of the flow path, the air conditioning control unit 402 includes the cooling tower 1 and the refrigerator so that the indoor air temperature approaches the target temperature. 2. Control the operation of the air conditioner 3 and the pumps 5 and 6.

  As described above, in the air conditioning system according to the embodiment of the present invention, the refrigerator 2 includes a part of the cooling water that circulates between the cooling tower 1 and the cooling water. The remainder is provided with the 3rd flow path mixed with the cold water circulated between the air conditioners 3. For this reason, it becomes possible to extend the air-conditioning period using free cooling irrespective of a complicated structure.

  In addition, this invention is not limited to the said embodiment, Of course, the various change in the range which does not deviate from the summary of this invention is possible.

  For example, the cooling tower 1 may employ a cooling system (open type) in which the cooling water returned from the refrigerator 2 is brought into direct contact with the outside air to perform heat exchange. In this case, there is a merit that the cooling efficiency is increased, but there is also a demerit that the quality of the cooling water is lowered. For this reason, when an open type is adopted, a dirt filter may be provided between the cooling tower 1 and the pump 5.

  Moreover, you may make it the structure which can respond the refrigerator 2 to heating operation. In this case, as shown in FIG. 10, a four-way valve 27 is provided in the refrigerant circuit of the refrigerator 2 and is switched as shown by the solid line in FIG. 10 during the cooling operation. Accordingly, the refrigerant circulates in the order of the compressor 20, the four-way valve 27, the first heat exchanger 21, the expansion valve 22, and the second heat exchanger 23. On the other hand, during the heating operation, the four-way valve 27 is switched as indicated by a broken line. Accordingly, the refrigerant circulates in the order of the compressor 20, the four-way valve 27, the second heat exchanger 23, the expansion valve 22, and the first heat exchanger 21.

  If it carries out as mentioned above, in a heating operation, since a high temperature and a high voltage | pressure refrigerant | coolant can be flowed into the 2nd heat exchanger 23, it becomes possible to supply warm water to the air conditioner 3. FIG.

  Further, in place of the three-way valves 24 and 25, electromagnetic valves 28 and 29 may be provided as shown in FIG.

  Further, in order to ensure the stability of operation, a gas vent valve, a buffer tank, or the like may be provided as appropriate.

  The pumps 5 and 6 may be included in the configuration of the refrigerator 2.

  Further, the user instructs the type of the cooling water usage mode via the input device 43, and the air conditioning control unit 402 switches the flow path according to the type of the cooling water usage mode instructed by the user of the refrigerator 2. The control board 26 may be commanded.

  In the above embodiment, each function unit (see FIG. 8) of the control device 4 is realized by the CPU 40 executing a program related to air conditioning control. However, all or part of the functional units of the control device 4 may be realized by dedicated hardware. The dedicated hardware is, for example, a single circuit, a composite circuit, a programmed processor, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof.

  In the above embodiment, the program executed by the control device 4 is a CD-ROM (Compact Disc Read Only Memory), a DVD (Digital Versatile Disc), a magneto-optical disc (Magneto-Optical Disc), or a USB (Universal Serial). It is also possible to store and distribute in a computer-readable recording medium such as a Bus) memory, a memory card, and an HDD (Hard Disc Drive). It is also possible to cause the computer to function as the control device 4 in the above-described embodiment by installing such a program on a specific or general-purpose computer.

  Further, the program may be stored in a disk device or the like of a server on a network such as the Internet, and the program may be downloaded from the server to a computer.

  Various embodiments and modifications can be made to the present invention without departing from the broad spirit and scope. Further, the above-described embodiment is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications within the scope of the claims and within the scope of the equivalent invention are considered to be within the scope of the present invention.

  The present invention can be suitably employed in an air conditioning system that performs air conditioning in a building.

  DESCRIPTION OF SYMBOLS 1 Cooling tower, 2 Refrigerator, 3 Air conditioner, 4 Control apparatus, 5, 6 Pump, 7, 8 Piping, 20 Compressor, 21 1st heat exchanger, 22 Expansion valve, 23 2nd heat exchanger, 24, 25 Three-way valve, 26, 32 Control board, 27 Four-way valve, 28, 29 Solenoid valve, 30 Heat exchanger, 31 Fan, 40 CPU, 41 ROM, 42 RAM, 43 Input device, 44 Display, 45 Communication interface, 46 Two Next storage device, 47 bus, 400 user interface processing unit, 401 mode determination unit, 402 air conditioning control unit

Claims (6)

A refrigerant circuit;
A first heat exchanger for exchanging heat between the first circulating water circulating between the cooling tower and the refrigerant circulating in the refrigerant circuit;
A second heat exchanger that exchanges heat between the second circulating water circulating between the load device and the refrigerant;
A first flow path through which all of the first circulating water passes through the first heat exchanger;
A second flow path through which all of the first circulating water passes through the load device;
A third flow path in which a portion of the first circulating water passes through the first heat exchanger and the remainder of the first circulating water mixes with the second circulating water;
A refrigerator comprising: switching means for switching the flow path of the first circulating water to any one of the first flow path, the second flow path, and the third flow path.   The refrigerator according to claim 1, further comprising a switching control unit that receives a switching command from the outside and controls the switching unit to switch to a flow path specified by the switching command. A cooling tower, a refrigerator, and a load device;
The refrigerator is
A refrigerant circuit;
A first heat exchanger for exchanging heat between the first circulating water circulating between the cooling tower and the refrigerant circulating through the refrigerant circuit;
A second heat exchanger for exchanging heat between the second circulating water circulating between the load device and the refrigerant;
A first flow path through which all of the first circulating water passes through the first heat exchanger;
A second flow path through which all of the first circulating water passes through the load device;
A third flow path in which a portion of the first circulating water passes through the first heat exchanger and the remainder of the first circulating water mixes with the second circulating water;
An air conditioning system comprising: switching means for switching the flow path of the first circulating water to any one of the first flow path, the second flow path, and the third flow path.   The air conditioning system according to claim 3, wherein the refrigerator further includes a switching control unit that receives a switching command from the outside and controls the switching unit to switch to the flow path specified by the switching command.   5. The control device according to claim 4, further comprising a control device that transmits the switching command designating any one of the first flow channel, the second flow channel, and the third flow channel to the refrigerator. Air conditioning system.   The control device determines one of the normal mode, the first free cooling mode, and the second free cooling mode based on the temperature of the outside air, and when the determined mode is the normal mode, A switching command specifying the first flow path is transmitted to the refrigerator, and if the determined mode is the first free cooling mode, a switching command specifying the second flow path is transmitted to the refrigerator and determined. The air conditioning system according to claim 5, wherein when the mode is the second free cooling mode, a switching command specifying the third flow path is transmitted to the refrigerator.

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