WO2025017823A1 - 熱源システム - Google Patents

熱源システム Download PDF

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Publication number
WO2025017823A1
WO2025017823A1 PCT/JP2023/026225 JP2023026225W WO2025017823A1 WO 2025017823 A1 WO2025017823 A1 WO 2025017823A1 JP 2023026225 W JP2023026225 W JP 2023026225W WO 2025017823 A1 WO2025017823 A1 WO 2025017823A1
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WO
WIPO (PCT)
Prior art keywords
heat source
heat
defrosting operation
source units
capacity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2023/026225
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English (en)
French (fr)
Japanese (ja)
Inventor
翔平 竹中
仁隆 門脇
善生 山野
武徳 松本
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP2025533760A priority Critical patent/JPWO2025017823A1/ja
Priority to PCT/JP2023/026225 priority patent/WO2025017823A1/ja
Priority to GB2518869.9A priority patent/GB2644528A/en
Publication of WO2025017823A1 publication Critical patent/WO2025017823A1/ja
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles

Definitions

  • This disclosure relates to a heat source system equipped with multiple heat source units.
  • a heat source system equipped with multiple heat source units if at least one heat source unit starts a defrosting operation during heating operation, the number of heat source units performing heating operation decreases, and the total heating capacity of the heat source system decreases.
  • the temperature of the heat medium, such as water, supplied to the load unit decreases.
  • the heat source system of Patent Document 1 proposes increasing the pump frequency and the flow rate of the heat medium when a drop in the temperature of the heat medium due to defrosting operation is detected.
  • the present disclosure aims to solve the above problems and provide a heat source system that can suppress the temperature drop of the heat medium during defrosting operation.
  • the heat source system comprises a plurality of heat source units and a control device that controls the plurality of heat source units, each of which comprises a refrigerant circuit to which a compressor, an outdoor heat exchanger, an expansion valve, and a heat medium heat exchanger are connected, and the heat medium heat exchanger exchanges heat between the refrigerant flowing through the refrigerant circuit and the heat medium supplied to the load unit, and the control device detects that at least one of the plurality of heat source units is scheduled to start a defrosting operation, and before the defrosting operation is started, performs a capacity increase operation that increases the total heating capacity of the heat source units other than the heat source unit scheduled to start the defrosting operation.
  • the heat source system disclosed herein detects that the heat source unit is scheduled to start a defrosting operation and performs a capacity increase operation before the defrosting operation starts, so that the heating capacity before advance detection can be maintained even during the defrosting operation. This makes it possible to suppress a drop in the temperature of the heat medium supplied to the load unit during the defrosting operation.
  • FIG. 1 is a schematic configuration diagram of a refrigeration cycle device according to a first embodiment.
  • 1 is a schematic configuration diagram of a heat source unit according to a first embodiment.
  • FIG. FIG. 2 is a control block diagram of the heat source system according to the first embodiment.
  • 4 is a flowchart showing the flow of operation of the heat source system according to the first embodiment.
  • 10 is a flowchart showing the flow of a capacity increasing process in the first embodiment.
  • 4 is a diagram illustrating an example of a state transition of the heat source system according to the first embodiment.
  • FIG. FIG. 11 is a diagram showing changes in heating capacity and outlet temperature during defrosting operation in a heat source system according to the conventional technology.
  • 5 is a diagram showing changes in heating capacity and outlet temperature during defrosting operation in the heat source system according to embodiment 1.
  • FIG. 1 is a schematic diagram of a refrigeration cycle apparatus 100 according to the first embodiment.
  • the refrigeration cycle apparatus 100 according to the first embodiment is a heat pump chiller that performs air conditioning using a heat medium flowing through a heat medium circuit 40.
  • the refrigeration cycle apparatus 100 includes a heat source system 1 and a plurality of load units 2. In the example of FIG. 1, two load units 2 are shown, but the number of the load units 2 may be one or three or more.
  • the heat source system 1 includes a plurality of heat source units 10A, 10B, 10C, and 10D, and a control device 5.
  • the plurality of heat source units 10A, 10B, 10C, and 10D are connected in parallel to each other with respect to the heat medium circuit 40.
  • FIG. 2 is a schematic diagram of the heat source unit 10A according to the first embodiment.
  • Heat source units 10B, 10C, and 10D have the same configuration as heat source unit 10A.
  • heat source unit 10A includes two refrigerant circuits 11, a heat medium heat exchanger 41 shared by the two refrigerant circuits 11, and a pump 42.
  • each refrigerant circuit 11 of the heat source unit 10A includes a compressor 12, a flow path switching valve 13, an outdoor heat exchanger 14, an expansion valve 15, a heat medium heat exchanger 41, and an accumulator 16.
  • the compressor 12, the flow path switching valve 13, the outdoor heat exchanger 14, the expansion valve 15, the heat medium heat exchanger 41, and the accumulator 16 are connected by piping to form the refrigerant circuit 11.
  • the refrigerant flowing through the refrigerant circuit 11 is, for example, a single refrigerant such as R-22 or R- 134a , a pseudo-azeotropic mixed refrigerant such as R-410A or R-404A, or a non-azeotropic mixed refrigerant such as R- 407C .
  • the compressor 12 compresses the sucked refrigerant and discharges it.
  • the compressor 12 is driven via an inverter drive device (not shown) or the like.
  • the operating frequency of the compressor 12 is controlled by the control device 5. By controlling the operating frequency of the compressor 12, it is possible to change the capacity of the compressor 12, which is the amount of refrigerant pumped out per unit time.
  • the flow path switching valve 13 switches between cooling operation and defrosting operation in which the outdoor heat exchanger 14 functions as a condenser, and heating operation in which the outdoor heat exchanger 14 functions as an evaporator.
  • the flow path switching valve 13 is, for example, a four-way valve, and switching is controlled by the control device 5.
  • the flow path switching valve 13 is switched so that the refrigerant discharged from the compressor 12 flows into the outdoor heat exchanger 14, as shown by the solid line in Figure 1.
  • the flow path switching valve 13 is switched so that the refrigerant discharged from the compressor 12 flows into the heat medium heat exchanger 41, as shown by the dashed line in Figure 1.
  • the outdoor heat exchanger 14 is, for example, a fin-tube type heat exchanger, and exchanges heat between the refrigerant flowing inside the heat transfer tubes and the air supplied by the outdoor fan 17.
  • heating operation heating operation
  • the outdoor heat exchanger 14 functions as an evaporator, and exchanges heat between the low-pressure refrigerant flowing in from the expansion valve 15 side and the air, evaporating the refrigerant and vaporizing it.
  • the outdoor heat exchanger 14 functions as a condenser, and exchanges heat between the high-pressure refrigerant flowing in from the compressor 12 side and the air, condensing the refrigerant and liquefying it.
  • the expansion valve 15 expands the refrigerant to reduce the pressure.
  • the expansion valve 15 is an electronic expansion valve with an adjustable opening.
  • the opening of the expansion valve 15 is controlled by the control device 5.
  • the expansion valve 15 may be a temperature-sensing expansion valve whose opening changes based on the temperature of the refrigerant.
  • the accumulator 16 is provided on the suction side of the compressor 12 and stores excess refrigerant in the refrigerant circuit 11.
  • the accumulator 16 is not an essential component of the refrigerant circuit 11 and may be omitted.
  • the outdoor fan 17 sends air to the outdoor heat exchanger 14, promoting heat exchange between the refrigerant and the air.
  • the outdoor fan 17 is driven via an inverter drive device (not shown) or the like.
  • the rotation speed of the outdoor fan 17 is controlled by the control device 5.
  • the air volume can be changed by controlling the rotation speed of the outdoor fan 17.
  • the outdoor heat exchanger 14 and the outdoor fan 17 are in one-to-one correspondence, but this is not limited to the above, and multiple outdoor fans 17 may be provided for one outdoor heat exchanger 14.
  • the heat medium heat exchanger 41 exchanges heat between the heat medium flowing through the heat medium circuit 40 and the refrigerant flowing through the refrigerant circuit 11.
  • the heat medium is water, brine (antifreeze), or a mixture of water and brine, and in this disclosure, it particularly refers to a heat medium other than a refrigerant.
  • the heat medium is water will be described, but all places where water is described will be replaced with a heat medium.
  • the heat medium heat exchanger 41 becomes a flow path of the two refrigerant circuits 11 and a flow path of the heat medium circuit 40. Therefore, the heat medium heat exchanger 41 becomes a device that constitutes the refrigerant circuit 11 and a device that constitutes the heat medium circuit 40.
  • the heat medium heat exchanger 41 functions as a condenser, exchanging heat between the refrigerant flowing from the compressor 12 and water, condensing the refrigerant to liquefy it or to two-phase gas-liquid, and heating the water.
  • the heat medium heat exchanger 41 functions as a condenser, exchanging heat between the refrigerant flowing from the compressor 12 and water, condensing the refrigerant to liquefy it or to two-phase gas-liquid, and heating the water.
  • it functions as an evaporator, exchanging heat between the refrigerant flowing in through the expansion valve 15 and water, evaporating the refrigerant and cooling the water.
  • the pump 42 draws in water flowing through the heat medium circuit 40, applies pressure to send it out, and circulates the heat medium circuit 40.
  • the pump 42 is driven via an inverter drive device (not shown) or the like.
  • the operating frequency of the pump 42 is controlled by the control device 5. By controlling the operating frequency of the pump 42, the capacity of the pump 42 can be changed.
  • the heat source unit 10A also includes an inlet temperature sensor 31, an outlet temperature sensor 32, a heat exchanger temperature sensor 33, and an outdoor air temperature sensor 34.
  • the inlet temperature sensor 31 is provided upstream of the heat medium heat exchanger 41 in the water flow direction, and measures an inlet temperature Tin, which is the temperature of the water flowing into the heat medium heat exchanger 41.
  • the outlet temperature sensor 32 is provided downstream of the heat medium heat exchanger 41 in the water flow direction, and measures an outlet temperature Tout, which is the temperature of the water flowing out of the heat medium heat exchanger 41.
  • the heat exchanger temperature sensor 33 measures a refrigerant temperature Tr, which is the temperature of the refrigerant flowing through the outdoor heat exchanger 14 of each refrigerant circuit 11.
  • the outdoor air temperature sensor 34 measures an outdoor air temperature Te, which is the temperature of the outdoor space in which the heat source unit 10A is installed.
  • Each temperature sensor is, for example, a thermistor, and outputs the measured temperature to the control device 5.
  • each heat source unit 10A to 10D is configured to have an outside air temperature sensor 34, but this is not limited to the configuration, and it is sufficient that the heat source system 1 is configured to have at least one outside air temperature sensor 34.
  • the load unit 2 is a unit that sends conditioned air to the indoor space that is the target of air conditioning.
  • each load unit 2 in this embodiment has an indoor heat exchanger 21, a flow rate adjustment valve 22, and an indoor fan 23.
  • the indoor heat exchanger 21 and the flow rate adjustment valve 22 are devices that make up the heat medium circuit 40.
  • the heat medium circuit 40 is configured by connecting the indoor heat exchanger 21 and the flow rate adjustment valve 22 of the load unit 2, the heat medium heat exchangers 41 of the heat source units 10A to 10D, and the pump 42 with piping.
  • the indoor heat exchanger 21 is, for example, a fin-tube type heat exchanger, and exchanges heat between the refrigerant flowing inside the heat transfer tube and the air supplied by the outdoor fan 17.
  • the indoor heat exchanger 21 exchanges heat between the refrigerant flowing inside the heat transfer tube and the air supplied by the outdoor fan 17.
  • water that is colder than the air passes through the heat transfer tube of the indoor heat exchanger 21, cooling the indoor space.
  • water that is warmer than the air passes through the heat transfer tube of the indoor heat exchanger 21, heating the indoor space.
  • the flow rate control valve 22 is, for example, a two-way valve that can control the opening degree (opening area) of the valve.
  • the flow rate control valve 22 controls the flow rate of water flowing into or out of the indoor heat exchanger 21 depending on the opening degree.
  • the flow rate control valve 22 adjusts the amount of water passing through the indoor heat exchanger 21 based on the temperature of the water flowing into the load unit 2 and the temperature of the water flowing out, so that the indoor heat exchanger 21 can exchange heat with an amount of heat according to the thermal load in the room.
  • the flow rate control valve 22 when the indoor heat exchanger 21 does not need to exchange heat with the thermal load, such as when it is stopped or thermo is OFF, the flow rate control valve 22 is in a fully closed state, and the supply of water can be stopped so that water does not flow into or out of the indoor heat exchanger 21.
  • the flow rate control valve 22 is installed in the piping on the water inflow side of the indoor heat exchanger 21, but the flow rate control valve 22 may be installed on the water outflow side of the indoor heat exchanger 21.
  • the indoor fan 23 generates an air flow that passes the air in the indoor space through the indoor heat exchanger 21 and returns it to the indoor space.
  • the indoor fan 23 is driven via an inverter drive device (not shown) or the like.
  • the rotation speed of the indoor fan 23 is controlled by the control device 5.
  • the air volume can be changed by controlling the rotation speed of the indoor fan 23.
  • the control device 5 controls the operation of the heat source system 1.
  • the control device 5 is composed of a computer equipped with a memory for storing data and programs required for control and a processor such as a CPU for executing programs, a dedicated processing circuit such as an ASIC or FPGA, or both.
  • the control device 5 may also control the load units 2.
  • each load unit 2 may have its own control device that controls the load unit 2.
  • FIG. 3 is a control block diagram of the heat source system 1 according to the first embodiment.
  • the control device 5 of the heat source system 1 controls each of the heat source units 10A to 10D based on the measurement results of each temperature sensor provided in each of the heat source units 10A to 10D and instructions from a remote control (not shown).
  • the control device 5 has an operation control unit 51, a pre-detection unit 52, a capacity increase unit 53, and a storage unit 54.
  • the operation control unit 51, the pre-detection unit 52, and the capacity increase unit 53 are functional units that are realized by a processor provided in the control device 5 executing a program.
  • at least one of the operation control unit 51, the pre-detection unit 52, and the capacity increase unit 53 may be realized by a processing circuit such as an ASIC or an FPGA.
  • the operation control unit 51 controls each device of the heat source units 10A-10D, and performs cooling operation, heating operation, and defrosting operation in the refrigeration cycle device 100. Specifically, the operation control unit 51 controls the operating frequency of the compressor 12, the switching of the flow path switching valve 13, the opening degree of the expansion valve 15, the rotation speed of the outdoor fan 17, and the operating frequency of the pump 42 based on the operating mode setting and set temperature input by the user, and the measurement results of each temperature sensor.
  • the operation control unit 51 performs cooling or heating operation according to the operation mode setting and set temperature input by the user.
  • the operation control unit 51 controls the compressor 12, expansion valve 15, outdoor fan 17, and pump 42 so that the outlet temperature Tout measured by the outlet temperature sensor 32 becomes the target temperature Tm according to the set temperature.
  • the operation control unit 51 starts the defrosting operation of the heat source unit for which the defrosting conditions are satisfied.
  • the defrosting condition is not limited to the above, and may be, for example, that the refrigerant temperature Tr measured by the heat exchanger temperature sensor 33 becomes lower than the threshold temperature, or that the elapsed time since the end of the previous defrosting operation exceeds the threshold time, etc.
  • the operation control unit 51 performs defrosting by switching the flow path switching valve 13 of the heat source unit 10A-10D for which the defrosting conditions are satisfied in the same manner as during cooling operation and making the outdoor heat exchanger 14 function as a condenser. Note that the operation control unit 51 may start the defrosting operation of the heat source unit when both of the refrigerant temperatures Tr measured by the heat exchanger temperature sensors 33 of the two refrigerant circuits 11 provided in each of the heat source units 10A-10D satisfy the defrosting conditions, or may start the defrosting operation of the heat source unit when either one of the refrigerant temperatures satisfies the defrosting conditions.
  • the advance detection unit 52 advances detection of defrosting operation in the heat source units 10A-10D.
  • “Advance detection of defrosting operation” means detecting that a defrosting operation is scheduled to start in any of the heat source units 10A-10D before the defrosting operation actually starts.
  • “a defrosting operation is scheduled to start” includes not only cases where the start time of the defrosting operation has been set in advance, but also cases where it is expected that the defrosting operation will start.
  • the advance detection unit 52 advances detection of a defrosting operation, for example, when a state in which the difference ⁇ Tf between the refrigerant temperature Tr and the outside air temperature Te of any of the heat source units 10A-10D is equal to or greater than the threshold value Tth continues for a second time (e.g., 5 minutes) that is shorter than the first time, which is the defrosting condition.
  • the second time is preset so that the difference between the second time and the first time when defrosting starts is the time it takes for a stopped heat source unit to be started and for the outlet temperature Tout to follow the target temperature Tm, and is stored in the memory unit 54.
  • the capacity increase unit 53 increases the heating capacity of the heat source units 10A-10D that are not scheduled to start a defrosting operation.
  • the total heating capacity of the heat source system 1 decreases, and the temperature of the water supplied to the load unit 2, i.e., the outlet temperature Tout, decreases.
  • the capacity increase unit 53 increases the heating capacity of the heat source units that are not scheduled to start a defrosting operation to compensate for the decrease in heating capacity due to the defrosting operation of any of the heat source units 10A-10D.
  • the storage unit 54 is, for example, a non-volatile semiconductor memory such as a ROM or a flash memory, a volatile semiconductor memory such as a RAM, a HDD, or an SSD.
  • the storage unit 54 stores the programs executed by the control device 5 and various data such as thresholds used in executing the programs.
  • Fig. 4 is a flowchart showing the flow of the operation of the heat source system 1 according to the first embodiment. Each process in the flowchart of Fig. 4 is performed by the control device 5 when the refrigeration cycle device 100 is performing a heating operation.
  • the pre-detection unit 52 determines whether or not a defrosting operation of any of the heat source units 10A-10D has been pre-detected (S1). If a defrosting operation of any of the heat source units 10A-10D has not been pre-detected (S1: NO), the heating operation continues. On the other hand, if a defrosting operation of any of the heat source units 10A-10D has been pre-detected (S1: YES), the capacity increase unit 53 performs a capacity increase process (S2).
  • FIG. 5 is a flowchart showing the flow of the capacity increase process in embodiment 1.
  • the capacity increase unit 53 calculates the total heating capacity Qa of the heat source system 1 during the current heating operation and stores it in the memory unit 54 (S21).
  • the total heating capacity Qa of the heat source system 1 is the sum of the heating capacities of each heat source unit performing heating operation.
  • the heating capacity of each heat source unit performing heating operation is calculated by a known method based on the operating frequency of the compressor 12 of each heat source unit.
  • FIG. 6 is a diagram illustrating an example of state transitions of the heat source system 1 according to the first embodiment.
  • FIG. 6(a) shows an example of the operating states of the heat source units 10A to 10D during heating operation.
  • state (a) the heat source units 10A, 10B, and 10D are performing heating operation, and the heat source unit 10C is stopped.
  • the heating capacity of each of the heat source units 10A, 10B, and 10D is A
  • the total heating capacity Qa of the heat source system 1 is 3A.
  • the heating capacity Qa is balanced with the load of the load unit 2, and the temperature of the water supplied to the load unit 2 follows the target temperature Tm.
  • the temperature difference ⁇ Ta is the difference between the outlet temperature Tout and the inlet temperature Tin of any of the heat source units 10A, 10B, and 10D performing heating operation, or the average value of the differences between the outlet temperature Tout and the inlet temperature Tin of each of the heat source units 10A, 10B, and 10D performing heating operation.
  • the capacity increasing unit 53 calculates the target heating capacity Qb of the heat source system 1 (S23).
  • the target heating capacity Qb is a heating capacity required to suppress a decrease in the temperature of the water supplied to the load unit 2 even when any of the heat source units 10A to 10D starts a defrosting operation.
  • Qa is the total heating capacity of the heat source system 1 at the time of advance detection stored in step S21, and in the example of Figure 6, it is 3A.
  • B is the estimated amount of heat collected by the heat source unit scheduled to perform defrosting operation. The estimated amount of heat collected B is determined by the operating state of the compressor 12 of the heat source unit performing defrosting operation. If the operating frequency of the compressor 12 is constant, the amount of heat collected B can be calculated from the operating frequency of the compressor 12 and conditions such as the outside air temperature Te. If the operating frequency of the compressor 12 fluctuates, the amount of heat collected B during past defrosting operations is stored in the memory unit 54 and estimated from conditions such as the outside air temperature Te.
  • the capacity increasing unit 53 calculates the target temperature difference ⁇ Tb (S24).
  • the capacity increasing unit 53 increases the capacity of the heat source units 10A to 10D that are not scheduled to start a defrosting operation.
  • the capacity increasing unit 53 determines whether or not there is a heat source unit that is currently stopped (S25). If there is a heat source unit that is currently stopped, the capacity increasing unit 53 starts the stopped heat source unit (S26).
  • the capacity increasing unit 53 determines the number of heat source units to be started so that the number of heat source units performing a heating operation after the start of the defrosting operation is the same as the number of heat source units currently performing a heating operation. In other words, the capacity increasing unit 53 starts the same number of stopped heat source units as the number of heat source units scheduled to perform a defrosting operation.
  • step S26 If the number of stopped heat source units is less than the number of heat source units scheduled to perform a defrosting operation, all stopped heat source units are started. If there is no heat source unit that is currently stopped (S25: NO), that is, if all heat source units of the heat source system 1 are performing a heating operation, the processing of step S26 is skipped.
  • the capacity increasing unit 53 controls the heat source unit that is not scheduled to perform the defrosting operation so that the temperature difference (Tout-Tin) between the outlet temperature Tout and the inlet temperature Tin of the heat source unit that is not scheduled to perform the defrosting operation satisfies the target temperature difference ⁇ Tb (S27).
  • the processing of steps S25 to S27 is called "capacity increasing operation”.
  • FIG. 6B shows a state in which the heat source system 1 is in a capacity increasing operation.
  • the operation control unit 51 judges whether or not to start a defrosting operation in the heat source unit scheduled to perform the defrosting operation (S3). If the defrosting operation is not to be started (S3: NO), the increased capacity operation continues until the defrosting operation is started. On the other hand, if the defrosting operation is to be started (S3: YES), the operation control unit 51 switches the flow path switching valve 13 of the heat source unit performing the defrosting operation to make the outdoor heat exchanger 14 function as a condenser, and performs the defrosting operation (S4).
  • FIG. (c) in Figure 6 shows the state when the defrosting operation of heat source unit 10B is started.
  • state (c) shows the state when the defrosting operation of heat source unit 10B is started.
  • state (c) even after the defrosting operation of heat source unit 10B is started, the increased capacity operation continues in heat source units 10A, 10C, and 10D during heating operation.
  • the decrease in the temperature of the water supplied to load unit 2 can be suppressed.
  • the operation control unit 51 judges whether or not to terminate the defrosting operation (S5). If the defrosting operation is not to be terminated (S5: NO), the defrosting operation is continued. On the other hand, if the defrosting operation is to be terminated (S5: YES), the operation control unit 51 judges whether or not the number of heat source units currently performing the heating operation is the same as the number of units performing the heating operation before the advance detection (S6). Then, if the number of heat source units currently performing the heating operation is the same as the number of units performing the heating operation before the advance detection (S6: YES), the operation control unit 51 stops the heat source unit performing the defrosting operation (S7).
  • the operation control unit 51 switches the flow path switching valve 13 of the heat source unit performing the defrosting operation to the heating operation. (S8).
  • the capacity increase operation if the same number of stopped heat source units as the heat source units scheduled for defrost operation are started, the number of heat source units currently performing heating operation is the same as the number of heat source units performing heating operation before advance detection, so the heat source units performing defrost operation are stopped.
  • the capacity increase operation if there are no stopped heat source units or the number of stopped heat source units is fewer than the number of heat source units scheduled for defrost operation, the number of heat source units currently performing heating operation is fewer than the number of heat source units performing heating operation before advance detection, so the heat source units performing defrost operation are switched to heating operation. In this way, by keeping the number of heat source units performing heating operation as the same as much as possible in all of the heating operation, capacity increase operation, and defrost operation, the heat source system 1 can be operated efficiently.
  • FIG. 6 shows the state after the defrosting operation of the heat source unit 10B is completed.
  • the heat source unit 10B in state (b), when the defrosting operation of the heat source unit 10B is completed, the heat source unit 10B is stopped.
  • the outlet temperature Tout is controlled to satisfy the target temperature Tm, and the heating capacity of each heat source unit is reduced from A1 to A.
  • the total heating capacity Qa of the heat source system 1 becomes 3A.
  • FIG. 7 is a diagram showing the changes in heating capacity and outlet temperature Tout during defrosting operation in a heat source system according to the conventional technology.
  • the total heating capacity of the heat source system decreases.
  • the total heating capacity Qa of the heat source system before starting the defrosting operation is 3A
  • the total heating capacity of the heat source system becomes "2A - heat collection amount B by defrosting operation”.
  • the defrost operation reduces the heating capacity to 2A-B, causing the temperature of the water supplied to the load unit 2 to drop.
  • Conventional heat source systems increase the capacity of the heat source unit during heating operation when they detect a drop in the temperature of the water supplied to the load unit.
  • the supply water temperature continues to drop until the total heating capacity of the heat source system reaches the required heating capacity (3A). During this time, the temperature of the air supplied to the load unit 2 drops, reducing user comfort.
  • FIG. 8 is a diagram showing changes in heating capacity and outlet temperature Tout during defrosting operation in heat source system 1 according to embodiment 1.
  • a defrosting operation is detected in advance, and a capacity increase operation is performed.
  • a decrease in heat medium temperature during defrosting operation can be suppressed, and user comfort can be maintained.
  • Embodiment 2 A refrigeration cycle apparatus 100 according to the second embodiment is different from that according to the first embodiment in the timing of the execution of the capacity increase operation.
  • the configuration of the refrigeration cycle apparatus 100 according to the second embodiment is the same as that according to the first embodiment.
  • FIG. 9 is a flowchart showing the flow of the capacity increase process in embodiment 2.
  • the process of steps S201 to S204 in this embodiment is the same as the process of steps S21 to S24 in embodiment 1.
  • the capacity increase unit 53 calculates the target temperature difference ⁇ Tb, it calculates the start time ta of the capacity increase operation (S205).
  • the capacity increase unit 53 first calculates the required time ⁇ t until the total heating capacity of the heat source system 1 reaches the target heating capacity Qb. If there is a stopped heat source unit, the required time ⁇ t is the time until the stopped heat source unit starts and the target temperature difference ⁇ Tb is satisfied. Also, if there is no stopped heat source unit, the required time ⁇ t is the time until the heat source unit other than the heat source unit scheduled for defrost operation satisfies the target temperature difference ⁇ Tb.
  • the required time ⁇ t may be calculated in advance for each target temperature difference ⁇ Tb and operating state, and may be stored in the storage unit 54, or may be calculated using a function or the like with the target temperature difference ⁇ Tb and the operating state as variables. Then, the capacity increase unit 53 sets the time obtained by subtracting the required time ⁇ t from the defrost operation start time t1 as the start time ta of the capacity increase operation.
  • the capacity increase unit 53 judges whether the current time is the start time ta of the capacity increase operation (S206). If the current time is not the start time ta of the capacity increase operation (S206: NO), the capacity increase unit 53 waits until the current time becomes the start time ta of the capacity increase operation.
  • the capacity increase unit 53 performs the capacity increase operation similar to that of the first embodiment.
  • the processing of steps S207 to S209 is the same as the processing of steps S25 to S27 of the first embodiment. That is, in the first embodiment, the capacity increase operation is started at the timing when the defrosting operation is pre-detected, but in the present embodiment, the timing of the capacity increase operation is determined separately from the timing of the pre-detection.
  • FIG 10 is a diagram showing the changes in heating capacity and outlet temperature Tout during defrosting operation in the heat source system 1 of embodiment 2.
  • a defrosting operation is detected in advance at time t0, which is prior to time t1 at which any of the multiple heat source units performing heating operation starts a defrosting operation.
  • time ta which is after the time t0 at which the advance detection was made and prior to the start time t2 of the defrosting operation, a capacity increase operation is started.
  • the refrigeration cycle device 100 is a heat pump chiller, but the refrigeration cycle device 100 may be a dedicated heating device that does not have a device that can switch between heating and cooling, or a hot water supply device.
  • the refrigeration cycle device 100 is a dedicated heating device, the flow path switching valve 13 is omitted.
  • the heat source system 1 is configured to include four heat source units 10A-10D, but the number of heat source units may be two or more.
  • each heat source unit 10A-10D is configured to include two refrigerant circuits 11, but each heat source unit 10A-10D may include one refrigerant circuit 11, or three or more refrigerant circuits 11.
  • the heat source system 1 is controlled by a control device 5 provided separately from each of the heat source units 10A to 10D, but this is not limited to the above.
  • each of the heat source units 10A to 10D may have a control device, and the functional parts of the control device 5 of the heat source system 1 may be shared by the control devices of the heat source units 10A to 10D.
  • the control devices of the heat source units 10A to 10D may have an operation control unit 51 and a pre-detection unit 52, and one of the heat source units 10A to 10D may be a parent unit, and the control device of the parent unit may have a capacity increase unit 53.
  • each of the heat source units 10A to 10D detects in advance that it is planning to start a defrosting operation and notifies the parent unit.
  • the parent unit calculates the target temperature difference ⁇ Tb and notifies each of the heat source units 10A to 10D, thereby enabling the capacity increase operation before the start of the defrosting operation to be performed.
  • the defrosting operation is pre-detected when the state in which the difference ⁇ Tf between the refrigerant temperature Tr of any of the heat source units 10A to 10D and the outside air temperature Te is equal to or greater than the threshold value Tth continues for a second time, but the method of pre-detection is not limited to this.
  • the pre-detection unit 52 may estimate the defrosting start time when the defrosting condition is satisfied, and pre-detect the defrosting operation a second time (e.g., 5 minutes) before the defrosting start time that is set in advance.
  • the pre-detection unit 52 may estimate the time when the defrosting condition is reached from the increase rate of the difference ⁇ Tf between the refrigerant temperature Tr of any of the heat source units 10A to 10D and the outside air temperature Te, and pre-detect the defrosting operation a second time before the time when the defrosting condition is reached.
  • the pre-detection unit 52 may estimate the time when the defrosting condition is reached from the decrease rate of the refrigerant temperature Tr measured by the heat exchanger temperature sensor 33, and pre-detect the defrosting operation a second time before the time when the defrosting condition is reached.
  • the pre-detection unit 52 may detect a defrosting operation in advance when the time elapsed since the end of the previous defrosting operation becomes (threshold time - second time).
  • the heat source system 1 may end the capacity increase operation and return to the heating operation.
  • the operation control unit 51 judges whether the number of heat source units currently performing the heating operation is the same as the number of units performing the heating operation before the advance detection. If the number of heat source units currently performing the heating operation is the same as the number of units performing the heating operation before the advance detection, the heat source units are controlled so that the outlet temperature Tout of the heat source unit performing the heating operation satisfies the target temperature Tm.
  • the operation control unit 51 stops the heat source unit scheduled to perform the defrosting operation and controls the heat source unit so that the outlet temperature Tout of the heat source unit performing the heating operation satisfies the target temperature Tm. This makes it possible to prevent the capacity increase operation from continuing for a long time unintentionally.
  • 1 heat source system 1 heat source system, 2 load unit, 5 control device, 10A, 10B, 10C, 10D heat source unit, 11 refrigerant circuit, 12 compressor, 13 flow path switching valve, 14 outdoor heat exchanger, 15 expansion valve, 16 accumulator, 17 outdoor fan, 21 indoor heat exchanger, 22 flow rate control valve, 23 indoor fan, 31 inlet temperature sensor, 32 outlet temperature sensor, 33 heat exchanger temperature sensor, 34 outdoor air temperature sensor, 40 heat medium circuit, 41 heat medium heat exchanger, 42 pump, 51 operation control unit, 52 advance detection unit, 53 capacity increase unit, 54 memory unit, 100 refrigeration cycle device.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)
PCT/JP2023/026225 2023-07-18 2023-07-18 熱源システム Pending WO2025017823A1 (ja)

Priority Applications (3)

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JP2025533760A JPWO2025017823A1 (https=) 2023-07-18 2023-07-18
PCT/JP2023/026225 WO2025017823A1 (ja) 2023-07-18 2023-07-18 熱源システム
GB2518869.9A GB2644528A (en) 2023-07-18 2023-07-18 Heat source system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2023/026225 WO2025017823A1 (ja) 2023-07-18 2023-07-18 熱源システム

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05322265A (ja) * 1992-05-28 1993-12-07 Toshiba Corp 空気調和機
JPH06265244A (ja) * 1993-03-15 1994-09-20 Toshiba Corp 空気調和機
JP2005090785A (ja) * 2003-09-12 2005-04-07 Matsushita Electric Ind Co Ltd ヒートポンプ式給湯装置の除霜調節装置と制御方法
JP2013108732A (ja) * 2011-11-24 2013-06-06 Mitsubishi Heavy Ind Ltd ヒートポンプシステムの除霜運転方法及びヒートポンプシステム
WO2018042611A1 (ja) * 2016-09-02 2018-03-08 三菱電機株式会社 冷凍空調システム
WO2021001969A1 (ja) * 2019-07-03 2021-01-07 三菱電機株式会社 冷凍サイクル装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05322265A (ja) * 1992-05-28 1993-12-07 Toshiba Corp 空気調和機
JPH06265244A (ja) * 1993-03-15 1994-09-20 Toshiba Corp 空気調和機
JP2005090785A (ja) * 2003-09-12 2005-04-07 Matsushita Electric Ind Co Ltd ヒートポンプ式給湯装置の除霜調節装置と制御方法
JP2013108732A (ja) * 2011-11-24 2013-06-06 Mitsubishi Heavy Ind Ltd ヒートポンプシステムの除霜運転方法及びヒートポンプシステム
WO2018042611A1 (ja) * 2016-09-02 2018-03-08 三菱電機株式会社 冷凍空調システム
WO2021001969A1 (ja) * 2019-07-03 2021-01-07 三菱電機株式会社 冷凍サイクル装置

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JPWO2025017823A1 (https=) 2025-01-23

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