BACKGROUND OF THE INVENTION
Field of the Invention
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The present disclosure relates to an air conditioning apparatus, a control method for the air conditioning apparatus, and a control program of the air conditioning apparatus.
Description of the Related Art
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Japanese Patent Laid-Open No. 2019-15435 discloses an air conditioning apparatus including an outdoor unit and an indoor unit. The outdoor unit includes a gas engine that uses gas as a driving source, a first compressor that compresses refrigerant by obtaining a driving force from the gas engine, and a second compressor that uses an electric motor as a driving source.
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The present disclosure provides an air conditioning apparatus, a control method for the air conditioning apparatus, and a control program of the air conditioning apparatus that appropriately switch between independent operation of a second compressor and combined operation of a first compressor and the second compressor.
SUMMARY OF THE INVENTION
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An air conditioning apparatus in the present disclosure is an air conditioning apparatus in which a first compressor driven by a gas engine and a second compressor driven by a motor are connected in parallel, and air conditioning is performed by circulating refrigerant, the air conditioning apparatus including a control section configured to control driving of the first compressor and the second compressor, wherein the control section includes: a first drive control unit configured to, in a first period, drive only the first compressor and calculate a first air conditioning load indicative of an air conditioning load of the first period, when activating the air conditioning apparatus; and a second drive control unit configured to determine whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load, and the second drive control unit: determines to drive only the second compressor, when an intake differential temperature becomes equal to or less than a predetermined threshold value in the first period; in a second period, drives only the second compressor and calculates a second air conditioning load indicative of an air conditioning load of the second period, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period; and determines whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the second air conditioning load.
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A control method for an air conditioning apparatus in the present disclosure is a control method for an air conditioning apparatus in which a first compressor driven by a gas engine and a second compressor driven by a motor are connected in parallel, and air conditioning is performed by circulating refrigerant, the air conditioning apparatus including a control section configured to control driving of the first compressor and the second compressor, wherein the control section executes: a first control step of, in a first period, driving only the first compressor and calculating a first air conditioning load indicative of an air conditioning load of the first period, when activating the air conditioning apparatus; and a second control step of determining whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load, and the second control step includes: determining to drive only the second compressor, when an intake differential temperature becomes equal to or less than a predetermined threshold value in the first period; in a second period, driving only the second compressor and calculating a second air conditioning load indicative of an air conditioning load of the second period, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period; and determining whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the second air conditioning load.
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A control program of an air conditioning apparatus in the present disclosure is a control program of an air conditioning apparatus in which a first compressor driven by a gas engine and a second compressor driven by a motor are connected in parallel, and air conditioning is performed by circulating refrigerant, the control program causing a processor of a control section configured to control driving of the first compressor and the second compressor to function as: a first drive control unit configured to, in a first period, drive only the first compressor and calculate a first air conditioning load indicative of an air conditioning load of the first period, when activating the air conditioning apparatus; and a second drive control unit configured to determine whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load, wherein the second drive control unit: determines to drive only the second compressor, when an intake differential temperature becomes equal to or less than a predetermined threshold value in the first period; in a second period, drives only the second compressor and calculates a second air conditioning load indicative of an air conditioning load of the second period, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period; and determines whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the second air conditioning load.
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An air conditioning apparatus, a control method for the air conditioning apparatus, and a control program of the air conditioning apparatus according to the present disclosure can appropriately switch between independent operation of a second compressor and combined operation of a first compressor and the second compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
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- FIG. 1 is a refrigerant circuit diagram showing an air conditioning apparatus in Embodiment 1;
- FIG. 2 is a block diagram showing a configuration of control sections in Embodiment 1;
- FIG. 3 is a graph showing a relationship between an air conditioning load and efficiency in Embodiment 1;
- FIG. 4 is a timing chart showing an example of state transition of compressors in Embodiment 1;
- FIG. 5 is a timing chart showing another example of state transition of the compressors in Embodiment 1; and
- Fig. 6 is a flowchart showing an example of processing of an outdoor unit control section in Embodiment 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(Underlying Knowledge Forming Basis of Present Disclosure)
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When the inventors arrived at the idea of the present disclosure, there was an air conditioning apparatus including a gas engine that uses gas as a driving source, a first compressor that compresses refrigerant by obtaining a driving force from the gas engine, and a second compressor that uses an electric motor as a driving source.
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For example, it has been proposed, when activating the air conditioning apparatus, to drive only the first compressor during a first period and calculate a first air conditioning load indicative of an air conditioning load of the first period, and to appropriately switch between independent operation of the second compressor and combined operation of the first compressor and the second compressor, based on the first air conditioning load.
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However, with the above air conditioning apparatus, there was a case in which a thermostat turned off in the first period (for example, 5 minutes), since the first compressor has a higher capacity than the second compressor. In this way, the inventors have discovered it is possible that an entire target space has not reached a target temperature and that this hinders user comfort when the thermostat turns off after a short period of time. In order to solve the above problems, the inventors have arrived at the subject matter of the present disclosure.
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The present disclosure provides an air conditioning apparatus, a control method for the air conditioning apparatus, and a control program of the air conditioning apparatus that can appropriately switch between independent operation of a second compressor and combined operation of a first compressor and the second compressor.
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Hereinafter, embodiments will be described in detail with reference to the drawings. Note that excessively detailed description may be omitted. For example, details of matters already well known or overlapping description of substantially identical configurations may be omitted. This is to avoid unnecessary verbosity of the following description and to facilitate understanding by those skilled in the art.
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It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter set forth in the claims.
(Embodiment 1)
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Hereinafter, Embodiment 1 will be described using the drawings.
[1-1. Configuration, etc.]
[1-1-1. Configuration of Refrigerant Circuit]
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First, a refrigerant circuit constituting an air conditioning apparatus 1 will be described with reference to FIG. 1. FIG. 1 is a refrigerant circuit diagram showing the air conditioning apparatus 1 according to Embodiment 1.
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As shown in FIG. 1, the air conditioning apparatus 1 according to the present embodiment includes an outdoor unit 10 and an indoor unit 30. Note that in FIG. 1, only one indoor unit 30 is installed, whereas a plurality of indoor units 30 may be installed in parallel with respect to the outdoor unit 10.
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The outdoor unit 10 includes a gas engine 11, a first compressor 12, a motor 13, and a second compressor 14.
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The gas engine 11 drives the first compressor 12. The first compressor 12 is driven by the gas engine 11 and compresses refrigerant.
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The motor 13 drives the second compressor 14. The second compressor 14 is driven by the motor 13 and compresses the refrigerant.
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The first compressor 12 and the second compressor 14 are connected in parallel.
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In the present embodiment, the first compressor 12 has a higher capacity than the second compressor 14.
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Note that in the following description, "to drive the first compressor" means to cause the gas engine 11 to drive the first compressor 12. "To drive the second compressor" means to cause the motor 13 to drive the second compressor 14.
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Refrigerant discharge sides of the first compressor 12 and the second compressor 14 converge where an oil separator 15 is provided. The oil separator 15 separates oil included in discharge refrigerant gas from the first compressor 12 and the second compressor 14.
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An outdoor heat exchanger 17 is connected downstream of the oil separator 15 via a four-way valve 16. The four-way valve 16 switches a refrigeration cycle between a cooling operation and a heating operation. That is, in FIG. 1, the refrigerant flows in a direction indicated by solid arrows during the heating operation and the refrigerant flows in a direction indicated by dashed arrows during the cooling operation.
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A radiator 18 that cools cooling water of the gas engine 11 is disposed downwind of the outdoor heat exchanger 17. The outdoor heat exchanger 17 and an outdoor fan 19 that allows outside air to pass through the radiator 18 are disposed near the radiator 18.
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An outdoor expansion valve 20 is provided at one side of the outdoor heat exchanger 17. The outdoor expansion valve 20 is connected to the indoor unit 30 via refrigerant piping.
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The indoor unit 30 includes an indoor heat exchanger 31, an indoor fan 32, and an indoor expansion valve 33. Refrigerant piping 35 is connected to one end of the indoor heat exchanger 31 via the indoor expansion valve 33.
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The other end of the indoor heat exchanger 31 is connected to an intake pipe 36 of the first compressor 12 and the second compressor 14 via the four-way valve 16 and an accumulator 21.
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The indoor unit 30 corresponds to an example of an "indoor unit."
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A bypass pipe 22 that is connected to an intake side of the first compressor 12 and the second compressor 14 is connected midway of the refrigerant piping 35 that connects the outdoor heat exchanger 17 and the indoor heat exchanger 31. A waste heat recovery decompression apparatus 23 and a waste heat recovery heat exchanger 24 are provided along the bypass pipe 22.
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One end of an oil return pipe 25 is connected below the oil separator 15, and the other end of the oil return pipe 25 is connected to the intake pipe 36 of the first compressor 12 and the second compressor 14.
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Refrigerant temperature sensors 26 that detect a temperature of discharged refrigerant are provided at the discharge sides of the first compressor 12 and the second compressor 14.
[1-1-2. Control Configuration]
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A control configuration of the present embodiment will be described next with reference to FIG. 2. FIG. 2 is a block diagram showing the control configuration of the air conditioning apparatus 1 of the present embodiment.
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As shown in FIG. 2, the air conditioning apparatus 1 includes an outdoor unit control section 40 and an indoor unit control section 50. The outdoor unit control section 40 controls each unit of the outdoor unit 10. The indoor unit control section 50 controls each unit of the indoor unit 30.
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The outdoor unit control section 40 corresponds to an example of a "control section."
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A configuration of the outdoor unit control section 40 will be described first.
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The outdoor unit control section 40 includes an outdoor unit communication circuit 41, an outdoor unit processor 42, and an outdoor unit memory 43.
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The outdoor unit communication circuit 41 communicates with an indoor unit communication circuit 51 in accordance with an instruction from the outdoor unit processor 42. The outdoor unit communication circuit 41 receives a differential temperature signal SG from the indoor unit communication circuit 51. The differential temperature signal SG indicates an intake differential temperature ΔTP of the indoor unit 30.
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The outdoor unit processor 42 is a processor such as a central processing unit (CPU) or a microprocessing unit (MPU).
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The outdoor unit processor 42 may be a single processor or may be a plurality of processors.
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The outdoor unit processor 42 corresponds to an example of a "processor."
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The outdoor unit memory 43 is a memory for storing a program, data, or the like. The outdoor unit memory 43 stores an outdoor unit control program 431. The outdoor unit memory 43 includes a non-volatile storage area. The outdoor unit memory 43 may include a volatile storage area and may be implemented as a work area of the outdoor unit processor 42. The outdoor unit memory 43 is implemented as, for example, a read-only memory (ROM) or a random-access memory (RAM).
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The outdoor unit control program 431 corresponds to an example of a "control program."
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The outdoor unit control section 40 controls the first compressor 12, the second compressor 14, the outdoor fan 19, the outdoor expansion valve 20, and the like of the outdoor unit 10 of the air conditioning apparatus 1.
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The refrigerant temperature sensors 26 are connected to the outdoor unit control section 40.
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The outdoor unit processor 42 functions as a first drive control unit 421 and a second drive control unit 422. To be specific, the outdoor unit processor 42 functions as the first drive control unit 421 and the second drive control unit 422 by loading and executing the outdoor unit control program 431 from the outdoor unit memory 43.
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In a first period P1, when activating the air conditioning apparatus 1, the first drive control unit 421 drives only the first compressor 12 and calculates a first air conditioning load L1 indicative of an air conditioning load LD of the first period P1. The first period P1 is, for example, five minutes.
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In this way, when activating the air conditioning apparatus 1, damage to the compressors can be suppressed even when, for example, liquid-state refrigerant is lodged inside the compressor, since only the first compressor 12 is driven. This is because the second compressor 14 is more likely to be damaged than the first compressor 12 when compressing the liquid-state refrigerant.
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For example, the first drive control unit 421 calculates the first air conditioning load L1 based on a rated output of the first compressor 12, a rated output of the second compressor 14, an output of the first compressor 12, an output of the second compressor 14, the intake differential temperature ΔTP of the indoor unit 30, and the like.
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The intake differential temperature ΔTP indicates a difference between a target temperature and an intake temperature. The target temperature is set, for example, by a remote control 90. The intake temperature is a temperature of air that the indoor unit 30 takes in. The intake temperature is detected by an intake temperature sensor 34.
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The outdoor unit communication circuit 41 receives the differential temperature signal SG indicating the intake differential temperature ΔTP from the indoor unit communication circuit 51. The first drive control unit 421 acquires the intake differential temperature ΔTP from the outdoor unit communication circuit 41.
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The second drive control unit 422 determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the first air conditioning load L1.
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For example, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14, when the first air conditioning load L1 is equal to or greater than a first threshold value TH1. For example, the second drive control unit 422 determines to drive only the second compressor 14, when the first air conditioning load L1 is less than the first threshold value TH1.
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The first threshold value TH1 is, for example, "30%" of a maximum load. The maximum load is, for example, a sum of a rated capacity of the first compressor 12 and a rated capacity of the second compressor 14.
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The second drive control unit 422 determines to drive only the second compressor 14, when the intake differential temperature ΔTP in the indoor unit 30 becomes equal to or less than a predetermined threshold value ΔTHA in the first period P1.
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The intake differential temperature ΔTP indicates the difference between the target temperature and the intake temperature. The target temperature is set, for example, by the remote control 90. The intake temperature is the temperature of the air that the indoor unit 30 takes in. The intake temperature is detected by the intake temperature sensor 34.
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In the first period P1, the second drive control unit 422 determines whether the intake differential temperature ΔTP in the indoor unit 30 is equal to or less than the predetermined threshold value ΔTHA, when the outdoor unit communication circuit 41 receives the differential temperature signal SG from the indoor unit communication circuit 51. The differential temperature signal SG indicates the intake differential temperature ΔTP. The predetermined threshold value ΔTHA is, for example, "2°C."
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The predetermined threshold value ΔTHA is set to a value greater than a transition threshold value ΔTHB to be described below.
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In a second period P2 after the first period P1, the second drive control unit 422 drives only the second compressor 14 and calculates a second air conditioning load L2 indicative of an air conditioning load of the second period P2, when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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The second period P2 is, for example, a period of the same duration as the first period P1. In other words, the second period P2 is, for example, five minutes.
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For example, the second drive control unit 422 calculates the second air conditioning load L2 based on the rated output of the first compressor 12, the rated output of the second compressor 14, the output of the first compressor 12, the output of the second compressor 14, the intake differential temperature ΔTP of the indoor unit 30, and the like.
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The outdoor unit communication circuit 41 receives the differential temperature signal SG indicating the intake differential temperature ΔTP from the indoor unit communication circuit 51. The second drive control unit 422 acquires the intake differential temperature ΔTP from the outdoor unit communication circuit 41.
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The second drive control unit 422 determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the second air conditioning load L2.
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For example, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14, when the second air conditioning load L2 is equal to or greater than a second threshold value TH2. For example, the second drive control unit 422 determines to drive only the second compressor 14, when the second air conditioning load L2 is less than the second threshold value TH2.
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The second threshold value TH2 is, for example, equal to the first threshold value TH1. In other words, the second threshold value TH2 is, for example, 30% of the maximum load. The maximum load is, for example, the sum of the rated capacity of the first compressor 12 and the rated capacity of the second compressor 14.
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A configuration of the indoor unit control section 50 will be described next.
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The indoor unit control section 50 includes the indoor unit communication circuit 51, an indoor unit processor 52, and an indoor unit memory 53.
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The indoor unit communication circuit 51 communicates with the outdoor unit communication circuit 41 in accordance with an instruction from the indoor unit processor 52. The indoor unit communication circuit 51 transmits the differential temperature signal SG and the like to the outdoor unit communication circuit 41. The differential temperature signal SG indicates the intake differential temperature ΔTP.
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The indoor unit processor 52 is a processor such as a CPU or an MPU.
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The indoor unit processor 52 may be a single processor or may be a plurality of processors.
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The indoor unit memory 53 is a memory for storing a program, data, or the like. The indoor unit memory 53 stores an indoor unit control program 531. The indoor unit memory 53 includes a non-volatile storage area. The indoor unit memory 53 may include a volatile storage area and may be implemented as a work area of the indoor unit processor 52. The indoor unit memory 53 is implemented as, for example, a ROM or a RAM.
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The indoor unit control section 50 controls the indoor fan 32, the indoor expansion valve 33, and the like of the indoor unit 30 of the air conditioning apparatus 1.
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The indoor unit processor 52 functions as a drive control unit 521 and a transmission unit 522. To be specific, the indoor unit processor 52 functions as the drive control unit 521 and the transmission unit 522 by loading and executing the indoor unit control program 531 from the indoor unit memory 53.
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The drive control unit 521 controls each unit of the indoor unit 30 in accordance with settings information from the remote control 90.
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For example, the drive control unit 521 accepts instruction information from the remote control 90 to switch between an on/off state of the indoor unit 30.
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For example, the drive control unit 521 accepts instruction information from the remote control 90 to control an operation mode of the indoor unit 30. The operation mode includes a heating operation mode, a cooling operation mode, and a fan operation mode. The heating operation mode is an operation mode in which the drive control unit 521 causes the indoor unit 30 to execute the heating operation.
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The cooling operation mode is an operation mode in which the drive control unit 521 causes the indoor unit 30 to execute the cooling operation. The fan operation mode is an operation mode in which the drive control unit 521 causes the indoor unit 30 to perform a fan operation.
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For example, the drive control unit 521 accepts target temperature information from the remote control 90 to control each unit of the indoor unit 30 based on the target temperature.
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For example, the drive control unit 521 transitions to the fan operation when the intake differential temperature ΔTP becomes equal to or less than the transition threshold value ΔTHB during the execution of the heating operation or the cooling operation. The intake differential temperature ΔTP indicates the difference between the target temperature and the intake temperature. The target temperature is set, for example, by the remote control 90. The intake temperature is the temperature of the air that the indoor unit 30 takes in. The intake temperature is detected by the intake temperature sensor 34. The transition threshold value ΔTHB is, for example, "1°C."
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The transmission unit 522 causes the indoor unit communication circuit 51 to transmit the differential temperature signal SG to the outdoor unit communication circuit 41 while the drive control unit 521 is controlling the operation mode of the indoor unit 30. The differential temperature signal SG indicates the intake differential temperature ΔTP.
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In the present embodiment, only one indoor unit 30 is installed in the air conditioning apparatus 1, whereas a plurality of the indoor units 30 may also be installed in the air conditioning apparatus 1. In this case, for example, the second drive control unit 422 determines to drive only the second compressor 14, when the intake differential temperature ΔTP of at least one indoor unit 30 among the plurality of indoor units 30 becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1.
[1-1-3. Relationship Between Air Conditioning Load and Efficiency]
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A relationship between the air conditioning load LD and efficiency EF will be described next with reference to FIG. 3. FIG. 3 is a graph showing the relationship between the air conditioning load LD and the efficiency EF.
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In FIG. 3, a horizontal axis represents the air conditioning load LD and a vertical axis represents the efficiency EF.
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A graph G1 is a graph showing the relationship between the air conditioning load LD and the efficiency EF when driving only the second compressor 14. A graph G2 is a graph showing the relationship between the air conditioning load LD and the efficiency EF when driving only the first compressor 12. A graph G3 is a graph showing the relationship between the air conditioning load LD and the efficiency EF when driving both the first compressor 12 and the second compressor 14.
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By comparing the graph G1, the graph G2, and the graph G3, the following can be understood.
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That is, when the air conditioning load LD is within a first range LA, driving only the second compressor 14 achieves the best efficiency EF. The first range LA is equal to or less than a first load LD1.
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When the air conditioning load LD is within a second range LB, driving only the first compressor 12 achieves the best efficiency EF. The second range LB is equal to or greater than the first load LD1 and equal to or less than a second load LD2.
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When the air conditioning load LD is within a third range LC, driving both the first compressor 12 and the second compressor 14 achieves the best efficiency EF. The third range LC is equal to or greater than the second load LD2.
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A load THL indicates the air conditioning load LD at an intersection of the graph G1 and the graph G3. For example, the first threshold value TH1 and the second threshold value TH2 are set based on the load THL.
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Therefore, from the perspective of the efficiency EF, it is preferable to drive only the second compressor 14 when the air conditioning load LD is within the first range LA, to drive only the first compressor 12 when the air conditioning load LD is within the second range LB, and to drive both the first compressor 12 and the second compressor 14 when the air conditioning load LD is within the third range LC.
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However, since the first compressor 12 is driven by the gas engine 11, efficiency is good when the gas engine 11 is driven at a medium to high output, whereas efficiency is relatively poor when the gas engine 11 is driven at a low output.
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Therefore, in the present embodiment, the second drive control unit 422 determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the first air conditioning load L1. The second drive control unit 422 determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the second air conditioning load L2.
[1-2. Operation, etc.]
[1-2-1. Operation of Refrigerant Circuit]
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An operation of the air conditioning apparatus in the present embodiment will be described next with reference to FIG. 1.
(Cooling Operation)
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During the cooling operation, at least one of the first compressor 12 or the second compressor 14 is driven in accordance with the air conditioning load LD. The four-way valve 16 is configured to allow the refrigerant to flow in the direction indicated by the dashed arrows.
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The high-temperature and high-pressure gas refrigerant compressed by at least one of the first compressor 12 or the second compressor 14 flows into the oil separator 15. The gas refrigerant from which oil has been separated in the oil separator 15 passes through the four-way valve 16 and enters the outdoor heat exchanger 17. After undergoing heat exchange with the outside air and releases heat in the outdoor heat exchanger 17, the gas refrigerant is condensed, becomes high-pressure liquid refrigerant, passes through the outdoor expansion valve 20, and is supplied to the indoor unit 30.
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The high-pressure liquid refrigerant that has entered the indoor unit 30 is decompressed in the indoor expansion valve 33, brought into a gas-liquid two-phase state, and flows into the indoor heat exchanger 31. After undergoing heat exchange in the indoor heat exchanger 31 with air in a space to be air-conditioned and absorbing heat, the gas-liquid two-phase-state refrigerant evaporates, becomes gas refrigerant, and flows out from the indoor unit 30.
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The gas refrigerant that has flowed out from the indoor unit 30 returns again to the outdoor unit 10. The gas refrigerant that has flowed into the outdoor unit 10 passes through the four-way valve 16 and the accumulator 21, and returns to at least one of the first compressor 12 or the second compressor 14, repeating the above process.
(Heating Operation)
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During the heating operation, both the first compressor 12 and the second compressor 14 or only the second compressor 14 is driven in accordance with the air conditioning load LD. The four-way valve 16 is configured to allow the refrigerant to flow in the direction indicated by the solid arrows.
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The high-temperature and high-pressure gas refrigerant compressed by both the first compressor 12 and the second compressor 14 or only the second compressor 14 flows into the oil separator 15. The gas refrigerant from which oil has been separated in the oil separator 15 passes through the four-way valve 16 and is provided to the indoor unit 30.
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After flowing into the indoor heat exchanger 31, undergoing heat exchange with the air in the space to be air-conditioned, and releasing heat, the high-temperature and high-pressure gas refrigerant that has entered the indoor unit 30 is condensed, becomes liquid refrigerant, passes through the indoor expansion valve 33, and flows out from the indoor unit 30.
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The liquid refrigerant that has flowed out from the indoor unit 30 returns again to the outdoor unit 10. The liquid refrigerant that has flowed into the outdoor unit 10 is decompressed in the outdoor expansion valve 20, brought into the gas-liquid two-phase state, and flows into the outdoor heat exchanger 17. After undergoing heat exchange in the outdoor heat exchanger 17 with the outside air and absorbing heat, the gas-liquid two-phase-state refrigerant evaporates, becomes gas refrigerant, passes through the four-way valve 16 and the accumulator 21, and returns to both the first compressor 12 and the second compressor 14 or only the second compressor 14, repeating the above process.
[1-2-2. State Transition of Compressors]
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State transition of the compressors will be described next with reference to FIGS. 4 and 5.
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FIG. 4 is a timing chart showing an example of the state transition of the compressors in Embodiment 1. FIG. 4 is a timing chart of when the intake differential temperature ΔTP does not become equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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Upper portions of FIGS. 4 and 5 show a change in an on/off state of the first compressor 12, and lower portions of FIGS. 4 and 5 show a change in an on/off state of the second compressor 14. In the upper and lower portions of FIGS. 4 and 5, a horizontal axis represents a time T and a vertical axis represents the on/off state.
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As shown in FIG. 4, the air conditioning apparatus 1 is activated at a time T0, and the first drive control unit 421 drives only the first compressor 12 in the first period P1 from the time T0 to a time T1. The first drive control unit 421 calculates the first air conditioning load L1 indicative of the air conditioning load LD of the first period P1.
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The second drive control unit 422 determines to drive only the second compressor 14, when the first air conditioning load L1 is less than the first threshold value TH1.
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At the time T1, the first compressor 12 stops being driven and the second compressor 14 starts being driven.
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On the other hand, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14, when the first air conditioning load L1 is equal to or greater than the first threshold value TH1.
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As indicated by a dashed line in FIG. 4, the first compressor 12 continues being driven at the time T1. The second compressor 14 starts being driven at the time T1. That is, both the first compressor 12 and the second compressor 14 are driven at the time T1.
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FIG. 5 is a timing chart showing another example of the state transition of the compressors in Embodiment 1. FIG. 5 is a timing chart of when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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As shown in FIG. 5, the air conditioning apparatus 1 is activated at the time T0, and the first drive control unit 421 drives only the first compressor 12 in the first period P1 from the time T0 to the time T1. The first drive control unit 421 calculates the first air conditioning load L1 indicative of the air conditioning load LD of the first period P1.
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The second drive control unit 422 determines to drive only the second compressor 14 at the time T1, since the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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At the time T1, the first compressor 12 stops being driven and the second compressor 14 starts being driven. Only the second compressor 14 is driven in the second period P2 from the time T1 to a time T2. In the second period P2, the second drive control unit 422 calculates the second air conditioning load L2 indicative of the air conditioning load LD of the second period P2.
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The second drive control unit 422 determines to drive only the second compressor 14, when the second air conditioning load L2 is less than the second threshold value TH2.
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At the time T2, the first compressor 12 continues not being driven and the second compressor 14 continues being driven. That is, only the second compressor 14 is driven at the time T2.
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On the other hand, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14, when the second air conditioning load L2 is equal to or greater than the second threshold value TH2.
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As indicated by a dashed line in FIG. 5, the first compressor 12 starts being driven at the time T2. The second compressor 14 continues being driven at the time T2. That is, both the first compressor 12 and the second compressor 14 are driven at the time T2.
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As described with reference to FIGS. 4 and 5, the second drive control unit 422 determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the air conditioning load LD. Therefore, it is possible to appropriately switch between independent operation of the second compressor 14 and combined operation of the first compressor 12 and the second compressor 14, in accordance with the air conditioning load LD.
[1-2-3. Processing of Outdoor Unit Control Section]
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Processing of the outdoor unit control section 40 will be described next with reference to FIG. 6. Fig. 6 is a flowchart showing an example of processing of the outdoor unit control section 40 in Embodiment 1.
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As shown in FIG. 6, the first drive control unit 421 first drives the first compressor 12 when activating the air conditioning apparatus 1 in step S101.
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In this way, when activating the air conditioning apparatus 1, damage to the compressors can be suppressed even when, for example, the liquid-state refrigerant is lodged inside the compressor, since only the first compressor 12 is driven. This is because the second compressor 14 is more likely to be damaged than the first compressor 12 when compressing the liquid-state refrigerant.
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In step S103, the first drive control unit 421 next calculates the first air conditioning load L1. The first air conditioning load L1 is the air conditioning load LD of the first period P1.
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In step S105, the outdoor unit control section 40 next determines whether the first period P1 has elapsed since activating the air conditioning apparatus 1 in step S101.
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When the outdoor unit control section 40 determines that the first period P1 has not elapsed (NO in step S105), the processing returns to step S103. When the outdoor unit control section 40 determines that the first period P1 has elapsed (YES in step S105), the processing proceeds to step S107.
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In step S107, the second drive control unit 422 determines whether the intake differential temperature ΔTP is equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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When the second drive control unit 422 determines that the intake differential temperature ΔTP is equal to or less than the predetermined threshold value ΔTHA (YES in step S107), the processing proceeds to step S117. When the second drive control unit 422 determines that the intake differential temperature ΔTP is not equal to or less than the predetermined threshold value ΔTHA (NO in step S107), the processing proceeds to step S109.
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In step S109, the second drive control unit 422 determines whether the first air conditioning load L1 is equal to or greater than the first threshold value TH1.
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When the second drive control unit 422 determines that the first air conditioning load L1 is not equal to or greater than the first threshold value TH1 (NO in step S109), the processing proceeds to step S111.
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In step S111, the second drive control unit 422 drives the second compressor 14.
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In step S113, the second drive control unit 422 next stops driving the first compressor 12. The processing ends thereafter.
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When the second drive control unit 422 determines that the first air conditioning load L1 is equal to or greater than the first threshold value TH1 (YES in step S109), the processing proceeds to step S115.
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In step S115, the second drive control unit 422 drives the second compressor 14. The processing ends thereafter.
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In the case of YES in step S107, the second drive control unit 422 drives the second compressor 14 in step S117.
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In step S119, the second drive control unit 422 next stops driving the first compressor 12.
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In step S121, the second drive control unit 422 next calculates the second air conditioning load L2. The second air conditioning load L2 is the air conditioning load LD of the second period P2.
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The air conditioning apparatus 1 achieves the following effects through the processing in step S107, step S117, step S119, and step S121. That is, it is possible to suppress a decrease in user comfort, since the indoor unit 30 can suppress the thermostat repeatedly turning on and off especially when the air conditioning load LD is low.
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In step S123, the outdoor unit control section 40 next determines whether the second period P2 has elapsed since the first compressor 12 stops being driven in step S119.
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When the outdoor unit control section 40 determines that the second period P2 has not elapsed (NO in step S123), the processing returns to step S121. When the outdoor unit control section 40 determines that the second period P2 has elapsed (YES in step S123), the processing proceeds to step S125.
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In step S125, the second drive control unit 422 determines whether the second air conditioning load L2 is equal to or greater than the second threshold value TH2.
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When the second drive control unit 422 determines that the second air conditioning load L2 is not equal to or greater than the second threshold value TH2 (NO in step S125), the processing ends thereafter. When the second drive control unit 422 determines that the second air conditioning load L2 is equal to or greater than the second threshold value TH2 (YES in step S125), the processing proceeds to step S127.
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In step S127, the second drive control unit 422 drives the first compressor 12. The processing ends thereafter.
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Steps S101 to S103 correspond to an example of a "first control step."
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Steps S107 to S119 correspond to an example of a "second control step."
[1-3. Effects, etc.]
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As described above, the air conditioning apparatus 1 of the present embodiment is the air conditioning apparatus 1 in which the first compressor 12 driven by the gas engine 11 and the second compressor 14 driven by the motor 13 are connected in parallel, and air conditioning is performed by circulating the refrigerant, the air conditioning apparatus 1 including: the outdoor unit control section 40 that controls the driving of the first compressor 12 and the second compressor 14, wherein the outdoor unit control section 40 includes: the first drive control unit 421 that, in the first period P1, drive only the first compressor 12 and calculates the first air conditioning load L1 indicative of the air conditioning load LD of the first period P1, when activating the air conditioning apparatus 1; and the second drive control unit 422 that determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the first air conditioning load L1, and the second drive control unit 422 determines to drive only the second compressor 14, when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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With this, the second drive control unit 422 determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the first air conditioning load L1 indicative of the air conditioning load LD of the first period P1. Therefore, it is possible to appropriately switch between the independent operation of the second compressor 14 and the combined operation of the first compressor 12 and the second compressor 14.
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The second drive control unit 422 determines to drive only the second compressor 14, when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1. Therefore, it is possible to appropriately switch between the independent operation of the second compressor 14 and the combined operation of the first compressor 12 and the second compressor 14.
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In the present embodiment, the second drive control unit 422, in the second period P2, drives only the second compressor 14 and calculates the second air conditioning load L2 indicative of the air conditioning load LD of the second period P2, when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1. The second drive control unit 422 further determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the second air conditioning load L2.
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With this, the second drive control unit 422 determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the second air conditioning load L2 indicative of the air conditioning load LD of the second period P2, when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1. Therefore, it is possible to appropriately switch between the independent operation of the second compressor 14 and the combined operation of the first compressor 12 and the second compressor 14.
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In the present embodiment, the air conditioning apparatus 1 includes the plurality of indoor units 30, wherein the second drive control unit 422 determines to drive only the second compressor 14, when the intake differential temperature ΔTP of at least one indoor unit 30 among the plurality of indoor units 30 becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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With this, the second drive control unit 422 determines to drive only the second compressor 14, when the intake differential temperature ΔTP of at least one indoor unit 30 among the plurality of indoor units 30 becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1. Therefore, it is possible to appropriately switch between the independent operation of the second compressor 14 and the combined operation of the first compressor 12 and the second compressor 14, also when the air conditioning apparatus 1 includes the plurality of indoor units 30.
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In the present embodiment, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14 when the first air conditioning load L1 is equal to or greater than the first threshold value TH1, and determines to drive only the second compressor 14 when the first air conditioning load L1 is less than the first threshold value TH1.
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With this, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14 when the first air conditioning load L1 is equal to or greater than the first threshold value TH1, and determines to drive only the second compressor 14 when the first air conditioning load L1 is less than the first threshold value TH1. Therefore, it is possible to appropriately switch between the independent operation of the second compressor 14 and the combined operation of the first compressor 12 and the second compressor 14, by setting the first threshold value TH1 to an appropriate value.
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In the present embodiment, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14 when the second air conditioning load L2 is equal to or greater than the second threshold value TH2, and determines to drive only the second compressor 14 when the second air conditioning load L2 is less than the second threshold value TH2.
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With this, the second drive control unit 422 determines to drive both the first compressor 12 and the second compressor 14 when the second air conditioning load L2 is equal to or greater than the second threshold value TH2, and determines to drive only the second compressor 14 when the second air conditioning load L2 is less than the second threshold value TH2. Therefore, it is possible to appropriately switch between the independent operation of the second compressor 14 and the combined operation of the first compressor 12 and the second compressor 14, by setting the second threshold value TH2 to an appropriate value.
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A control method for the air conditioning apparatus 1 in the present embodiment is a control method for an air conditioning apparatus in which a first compressor driven by a gas engine and a second compressor driven by a motor are connected in parallel, and air conditioning is performed by circulating refrigerant, the air conditioning apparatus including a control section configured to control driving of the first compressor and the second compressor, wherein the control section executes: a first control step of, in a first period, driving only the first compressor and calculating a first air conditioning load indicative of an air conditioning load of the first period, when activating the air conditioning apparatus; and a second control step of determining whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load, and the second control step includes determining to drive only the second compressor, when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period.
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The control method for the air conditioning apparatus 1 in the present embodiment exhibits similar effects to the air conditioning apparatus in the present embodiment.
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The outdoor unit control program 431 of the air conditioning apparatus 1 in the present embodiment is the outdoor unit control program 431 of the air conditioning apparatus 1 in which the first compressor 12 driven by the gas engine 11 and the second compressor 14 driven by the motor 13 are connected in parallel, and air conditioning is performed by circulating the refrigerant, the control program 431 causing the outdoor unit processor 42 of the outdoor unit control section 40 that controls the driving of the first compressor 12 and the second compressor 14 to function as: the first drive control unit 421 that, in the first period P1, drives only the first compressor 12 and calculates the first air conditioning load L1 indicative of the air conditioning load LD of the first period P1, when activating the air conditioning apparatus 1; and the second drive control unit 422 that determines whether to drive both the first compressor 12 and the second compressor 14 or to drive only the second compressor 14, based on the first air conditioning load L1, wherein the second drive control unit 422 determines to drive only the second compressor 14, when the intake differential temperature ΔTP becomes equal to or less than the predetermined threshold value ΔTHA in the first period P1.
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The outdoor unit control program 431 of the air conditioning apparatus 1 in the present embodiment exhibits similar effects to the air conditioning apparatus 1 in the present embodiment.
(Other Embodiments)
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Note that Embodiment 1 has been described as an example of the technique disclosed in the present application. However, the technique in the present disclosure is not limited thereto and is also applicable to embodiments in which modifications, substitutions, additions, omissions, or the like have been made. Other embodiments will be exemplified below.
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In the present embodiment, a case has been described in which the "control section" is the outdoor unit control section 40, whereas the present embodiment is not limited thereto. The "control section" may control the driving of the first compressor 12 and the second compressor 14. The "control section" may, for example, have the functions of the outdoor unit control section 40 and the indoor unit control section 50. That is, the "control section" may control, for example, each unit of the outdoor unit 10 and the indoor unit 30.
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In the present embodiment, a case has been described in which the second period P2 is, for example, a period of the same duration as the first period P1, whereas the present embodiment is not limited thereto. The second period P2 may be longer than the first period P1 or the second period P2 may be shorter than the first period P1.
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In the present embodiment, a case has been described in which the predetermined threshold value ΔTHA is "2°C" and the transition threshold value ΔTHB is "1°C," whereas the present embodiment is not limited thereto. For example, the predetermined threshold value ΔTHA may be greater than the transition threshold value ΔTHB.
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In the present embodiment, a case has been described in which the second threshold value TH2 is, for example, equal to the first threshold value TH1, whereas the present embodiment is not limited thereto. The second threshold value TH2 may be greater than the first threshold value TH1 or the second threshold value TH2 may be less than the first threshold value TH1.
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Each of the outdoor unit processor 42 and the indoor unit processor 52 may also be hardware programmed to realize corresponding functional units. That is, these processors may be implemented using, for example, an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA).
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Each of the outdoor unit communication circuit 41 and the indoor unit communication circuit 51 may perform wireless communication. For example, a standard such as Wi-Fi (R) or WiMax (R) is used as wireless connection.
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In the flowchart shown in Fig. 6, the processing steps of the outdoor unit control section 40 are divided in accordance with the main processing contents to facilitate understanding of the operation, whereas the operation is not limited by the manner in which the processing steps are divided or named. The processing steps may be further divided into additional steps in accordance with the processing contents. A single step may be further divided to include more processing. The order of these steps may be changed as appropriate provided that such changes do not depart from the spirit of the present disclosure.
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Note that since the above embodiments are provided to exemplify the technique in the present disclosure, various modifications, substitutions, additions, omissions, or the like can be made within the scope of the claims or equivalents thereof.
(Supplement)
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The above description of the embodiments discloses the following techniques.
(Technique 1)
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An air conditioning apparatus in which a first compressor driven by a gas engine and a second compressor driven by a motor are connected in parallel, and air conditioning is performed by circulating refrigerant, the air conditioning apparatus including a control section configured to control driving of the first compressor and the second compressor, wherein the control section includes: a first drive control unit configured to, in a first period, drive only the first compressor and calculate a first air conditioning load indicative of an air conditioning load of the first period, when activating the air conditioning apparatus; and a second drive control unit configured to determine whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load, and the second drive control unit: determines to drive only the second compressor, when an intake differential temperature becomes equal to or less than a predetermined threshold value in the first period; in a second period, drives only the second compressor and calculates a second air conditioning load indicative of an air conditioning load of the second period, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period; and determines whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the second air conditioning load.
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According to this configuration, the second drive control unit determines whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load indicative of the air conditioning load of the first period. Therefore, it is possible to appropriately switch between the independent operation of the second compressor and the combined operation of the first compressor and the second compressor.
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The second drive control unit determines to drive only the second compressor, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period. Therefore, it is possible to appropriately switch between the independent operation of the second compressor and the combined operation of the first compressor and the second compressor.
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The second drive control unit determines whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the second air conditioning load indicative of the air conditioning load of the second period, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period. Therefore, it is possible to appropriately switch between the independent operation of the second compressor and the combined operation of the first compressor and the second compressor.
(Technique 2)
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The air conditioning apparatus according to technique 1, further including a plurality of indoor units, wherein the second drive control unit determines to drive only the second compressor, when the intake differential temperature of at least one indoor unit among the plurality of indoor units becomes equal to or less than the predetermined threshold value in the first period.
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According to this configuration, the second drive control unit determines to drive only the second compressor, when the intake differential temperature of at least one indoor unit among the plurality of indoor units becomes equal to or less than the predetermined threshold value in the first period. Therefore, it is possible to appropriately switch between the independent operation of the second compressor and the combined operation of the first compressor and the second compressor, also when the air conditioning apparatus includes the plurality of indoor units.
(Technique 3)
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The air conditioning apparatus according to technique 1 or 2, wherein the second drive control unit: determines to drive both the first compressor and the second compressor, when the first air conditioning load is equal to or greater than a first threshold value; and determines to drive only the second compressor, when the first air conditioning load is less than the first threshold value.
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According to this configuration, the second drive control unit determines to drive both the first compressor and the second compressor when the first air conditioning load is equal to or greater than the first threshold value, and determines to drive only the second compressor when the first air conditioning load is less than the first threshold value. Therefore, it is possible to appropriately switch between the independent operation of the second compressor and the combined operation of the first compressor and the second compressor, by setting the first threshold value to an appropriate value.
(Technique 4)
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The air conditioning apparatus according to technique 1, wherein the second drive control unit:
determines to drive both the first compressor and the second compressor, when the second air conditioning load is equal to or greater than a second threshold value; and determines to drive only the second compressor, when the second air conditioning load is less than the second threshold value.
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According to this configuration, the second drive control unit determines to drive both the first compressor and the second compressor when the second air conditioning load is equal to or greater than the second threshold value, and determines to drive only the second compressor when the second air conditioning load is less than the second threshold value. Therefore, it is possible to appropriately switch between the independent operation of the second compressor and the combined operation of the first compressor and the second compressor, by setting the second threshold value to an appropriate value.
(Technique 5)
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A control method for an air conditioning apparatus in which a first compressor driven by a gas engine and a second compressor driven by a motor are connected in parallel, and air conditioning is performed by circulating refrigerant, the air conditioning apparatus including a control section configured to control driving of the first compressor and the second compressor, wherein the control section executes: a first control step of, in a first period, driving only the first compressor and calculating a first air conditioning load indicative of an air conditioning load of the first period, when activating the air conditioning apparatus; and a second control step of determining whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load, and the second control step includes: determining to drive only the second compressor, when an intake differential temperature becomes equal to or less than a predetermined threshold value in the first period; in a second period, driving only the second compressor and calculating a second air conditioning load indicative of an air conditioning load of the second period, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period; and determining whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the second air conditioning load.
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The control method for this air conditioning apparatus exhibits similar effects to the air conditioning apparatus according to technique 1.
(Technique 6)
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A control program of an air conditioning apparatus in which a first compressor driven by a gas engine and a second compressor driven by a motor are connected in parallel, and air conditioning is performed by circulating refrigerant, the control program causing a processor of a control section configured to control driving of the first compressor and the second compressor to function as: a first drive control unit configured to, in a first period, drive only the first compressor and calculate a first air conditioning load indicative of an air conditioning load of the first period, when activating the air conditioning apparatus; and a second drive control unit configured to determine whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the first air conditioning load, wherein the second drive control unit: determines to drive only the second compressor, when an intake differential temperature becomes equal to or less than a predetermined threshold value in the first period; in a second period, drives only the second compressor and calculates a second air conditioning load indicative of an air conditioning load of the second period, when the intake differential temperature becomes equal to or less than the predetermined threshold value in the first period; and determines whether to drive both the first compressor and the second compressor or to drive only the second compressor, based on the second air conditioning load.
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The control program of this air conditioning apparatus exhibits similar effects to the air conditioning apparatus according to technique 1.
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As described above, it is possible to advantageously use the air conditioning apparatus, the control method for the air conditioning apparatus, and the control program of the air conditioning apparatus according to the present disclosure for an air conditioning apparatus that appropriately switches between the independent operation of the second compressor and the combined operation of the first compressor and the second compressor.
Reference Signs List
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- 1 air conditioning apparatus
- 10 outdoor unit
- 11 gas engine
- 12 first compressor
- 13 motor
- 14 second compressor
- 30 indoor unit
- 31 indoor heat exchanger
- 34 intake temperature sensor
- 40 outdoor unit control section (control section)
- 41 outdoor unit communication circuit
- 42 outdoor unit processor (processor)
- 421 first drive control unit
- 422 second drive control unit
- 43 outdoor unit memory
- 431 outdoor unit control program (control program)
- 50 indoor unit control section
- 51 indoor unit communication circuit
- 52 indoor unit processor
- 521 drive control unit
- 522 transmission unit
- 53 indoor unit memory
- 531 indoor unit control program
- LD air conditioning load
- L1 first air conditioning load
- L2 second air conditioning load
- P1 first period
- P2 second period
- TH1 first threshold value
- TH2 second threshold value
- SG differential temperature signal
- ΔTHA predetermined threshold value
- ΔTHB transition threshold value
- ΔTP intake differential temperature