JP7315492B2 - refrigeration cycle equipment - Google Patents

Description

It relates to a refrigeration cycle device.

Conventionally, there is known a refrigeration cycle apparatus that sets an upper limit of current to be supplied to a compressor and controls the current used by the compressor to be equal to or lower than the upper limit, as disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-243814). In addition, Patent Document 1 (Japanese Patent Laid-Open No. 2009-243814) discloses that the upper limit of current is manually set from a plurality of candidates, or the upper limit of current is set based on the temperature difference between the suction temperature and the target temperature, and the current used in the compressor is controlled below the set upper limit.

However, when the upper limit value of current is manually set in advance, if the upper limit value is too small, the rise time (the time required for the temperature of the object to be temperature-adjusted to reach the target temperature from the start of operation) at the start of operation of the refrigeration cycle apparatus may become too long. Conversely, if the upper limit is set too large, the start-up time of the refrigeration cycle apparatus will be shortened, but the compressor may operate in a state of poor energy efficiency, and the energy consumption at the start of operation of the refrigeration cycle apparatus may increase.

A refrigeration cycle apparatus according to a first aspect includes a compressor and a controller. The controller controls the current of the compressor to be equal to or less than the current threshold. The controller changes the current threshold based on the amount of time the compressor is operated at the current threshold.

In the refrigeration cycle apparatus of the first aspect, the current threshold is changed according to the time during which the compressor is operated at the current threshold. Therefore, the refrigeration cycle apparatus of the first aspect optimizes the current threshold, suppresses the increase in the rise time of the refrigeration cycle apparatus, and suppresses the occurrence of a situation in which the rise time is excessively shortened and the power consumption at the start of operation increases.

A refrigeration cycle apparatus according to a second aspect is the refrigeration cycle apparatus according to the first aspect, wherein the controller raises the current threshold when the time during which the compressor is operated at the current threshold is longer than the first time.

In the refrigerating cycle device of the second aspect, control is performed to increase the current threshold when the time during which the compressor is operated at the current threshold is longer than the first time.

A refrigerating cycle apparatus according to a third aspect is the refrigerating cycle apparatus according to the second aspect, wherein the controller raises the current threshold when the time during which the compressor is continuously operated at the current threshold is longer than the first time.

In the refrigeration cycle apparatus of the third aspect, control is performed to raise the current threshold when the time during which the compressor is continuously operated at the current threshold is longer than a predetermined time. Therefore, when the current threshold is too small, it is easy to quickly improve this.

A refrigeration cycle apparatus according to a fourth aspect is the refrigeration cycle apparatus according to the first aspect, wherein the controller raises the current threshold when the time during which the compressor is operated at the current threshold is longer than the first time, and lowers the current threshold when the time during which the compressor is operated at the current threshold is shorter than the second time.

In the refrigeration cycle device of the fourth aspect, it is easy to quickly improve the startup time of the refrigeration cycle device too long or the current threshold too small.

The refrigeration cycle apparatus according to the fifth aspect is the refrigeration cycle apparatus according to the fourth aspect, wherein the controller raises the current threshold when the time during which the compressor is continuously operated at the current threshold is longer than the first time, and lowers the current threshold when the cumulative time during which the compressor is operated at the current threshold is shorter than the second time during the predetermined period.

In the refrigeration cycle device of the fifth aspect, it is easy to quickly improve the startup time of the refrigeration cycle device too long or the current threshold too small.

A refrigeration cycle apparatus according to a sixth aspect is the refrigeration cycle apparatus according to the second to fifth aspects, wherein the control unit controls the compressor so as to start operation of the refrigeration cycle apparatus one hour earlier than the set schedule.

In the refrigeration cycle apparatus of the sixth aspect, it is possible to suppress power consumption while operating so as to complete startup of the refrigeration cycle apparatus within the time of precooling operation and preheating operation when performing scheduled operation.

A refrigeration cycle apparatus according to a seventh aspect is the refrigeration cycle apparatus according to any one of the first aspect to the third aspect, wherein the controller lowers the current threshold when the accumulated time during which the compressor is operated at the current threshold during the predetermined period is shorter than the second time.

In the refrigeration cycle device of the seventh aspect, when the accumulated time during which the compressor is operated at the current threshold in the predetermined period is shorter than the second time, control is performed to lower the current threshold. Therefore, it is possible to suppress the occurrence of a situation in which the start-up time of the refrigeration cycle device becomes too short and the power consumption increases.

A refrigeration cycle apparatus according to an eighth aspect is the refrigeration cycle apparatus according to any one of the first aspect to the seventh aspect, wherein the control unit changes the current threshold by 1 to 4% of the design maximum value of the current of the compressor when changing the current threshold.

In the refrigeration cycle apparatus of the eighth aspect, it is possible to suppress the occurrence of a state in which the change in the current threshold is insufficient, or a state in which the change in the current threshold is too large and the current threshold needs to be changed in the opposite direction (hunting).

A refrigeration cycle apparatus according to a ninth aspect is the refrigeration cycle apparatus according to any one of the first to eighth aspects, wherein the control unit controls the current of the compressor to be equal to or less than the current threshold, using a predetermined initial value as a current threshold when the refrigeration cycle apparatus is powered on.

An appropriate value for the current threshold changes, for example, between heavy-load seasons and light-load seasons. Therefore, when the refrigerating cycle device is not used for a long period of time and the use is resumed after some time has passed since the previous use, the value that was appropriate as the current threshold during the previous use may deviate greatly from the current appropriate current threshold value. Then, for example, if the current threshold is excessively small relative to the appropriate value at the time of restarting use, there is a risk that the temperature of the object to be temperature-adjusted does not reach the target temperature for a long period of time at the start of operation or the like.

In contrast, in the refrigeration cycle apparatus of the ninth aspect, a predetermined initial value is used as the current threshold when the power is turned on. Therefore, if a relatively large value is adopted as the initial value, it is possible to suppress the occurrence of a situation in which the temperature of the object to be temperature-adjusted does not reach the target temperature for a long period of time at the start of operation.

A refrigeration cycle apparatus according to a tenth aspect is the refrigeration cycle apparatus according to any one of the first to ninth aspects, wherein when the refrigeration cycle apparatus is first used, a predetermined initial value is set as a current threshold, and the current of the compressor is controlled to be equal to or less than the current threshold. The control unit changes the current threshold to the initial value when the time during which the compressor is operated at the current threshold is longer than the third time.

In the refrigeration cycle apparatus of the tenth aspect, the current threshold can be returned to the initial value when the compressor is operated at the current threshold for a long period of time, in other words, when the current threshold is too small. Therefore, if a relatively large value is adopted as the initial value, it is possible to suppress the occurrence of a situation in which the temperature of the object to be temperature-adjusted does not reach the target temperature for a long period of time.

1 is a schematic configuration diagram of an air conditioner according to an embodiment; FIG. FIG. 2 is a control block diagram of the air conditioner in FIG. 1; FIG. 2 is an example of a flowchart of a first change process for the current threshold of the air conditioner of FIG. 1; FIG. FIG. 3 is an example of a flowchart of second change processing of the current threshold value of the air conditioner in FIG. 1 ; FIG. FIG. 4 is an example of a flowchart of third change processing of the current threshold value of the air conditioner in FIG. 1 ; FIG. FIG. 11 is an example of a flowchart of fourth change processing of the current threshold value of the air conditioner in FIG. 1 ; FIG. 2 is a diagram conceptually showing the relationship between the capacity and the coefficient of performance in the air conditioner of FIG. 1; FIG. FIG. 10 is a diagram conceptually showing an example of a current and a time change of the current threshold when the set current threshold value is too low. FIG. 7 is a diagram conceptually showing an example of a current and a time change of the current threshold when the value of the current threshold that has been set is too large.

Hereinafter, embodiments of a refrigeration cycle apparatus will be described with reference to the drawings.

(1) Overall Outline An air conditioner 100, which is an example of a refrigeration cycle apparatus, will be outlined with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic configuration diagram of an air conditioner 100. As shown in FIG. FIG. 2 is a control block diagram of the air conditioner 100. As shown in FIG.

The air conditioner 100 is a device that performs a vapor compression refrigeration cycle to cool or heat a space to be air-conditioned. Although not limited, the air-conditioned space is, for example, an office or a commercial facility. In this embodiment, the air conditioner 100 is a device capable of both cooling and heating an air-conditioned space. However, the air conditioner of the present disclosure is not limited to an air conditioner capable of both cooling and heating, and may be, for example, a device capable of only cooling. Also, the air conditioner 100 is merely an example of a refrigeration cycle device, and the refrigeration cycle device may be another type of device such as a water heater or a floor heating device that performs a vapor compression refrigeration cycle.

The air conditioner 100 mainly includes a heat source unit 10 , a utilization unit 30 , and a gas refrigerant communication pipe GP and a liquid refrigerant communication pipe LP that connect the heat source unit 10 and the utilization unit 30 .

In this embodiment, the air conditioner 100 includes three usage units 30 . However, the number of usage units 30 is not limited to three, and may be one, two, or four or more.

The gas refrigerant communication pipe GP and the liquid refrigerant communication pipe LP are laid at the installation site of the air conditioner 100 . The pipe diameters and pipe lengths of the gas refrigerant communication pipe GP and the liquid refrigerant communication pipe LP are selected according to design specifications and installation environment.

In the air conditioner 100, the heat source unit 10 and the utilization unit 30 are connected by a gas refrigerant communication pipe GP and a liquid refrigerant communication pipe LP to form a refrigerant circuit C. As shown in FIG. The refrigerant circuit C is filled with various refrigerants. The refrigerant circuit C includes the compressor 12 , the heat source heat exchanger 16 and the first expansion valve 18 of the heat source unit 10 and the utilization heat exchanger 32 and the second expansion valve 34 of each utilization unit 30 .

The heat source unit 10, the utilization unit 30, and the controller 90 including the first control section 22 of the heat source unit 10 and the second control section 38 of the utilization unit 30 and controlling the operation of various devices of the air conditioner 100 will be described below in detail.

(2) Detailed Configuration (2-1) Heat Source Unit The heat source unit 10 will be described.

The heat source unit 10 is installed, for example, on the roof of the building where the air conditioner 100 is installed, in a machine room, around the building, or the like.

The heat source unit 10 mainly includes a compressor 12, a flow direction switching mechanism 14, a heat source heat exchanger 16, a first expansion valve 18, a first fan 20, a discharge pressure sensor 24, a first controller 22, a first closing valve 13a, and a second closing valve 13b (see FIG. 1).

The heat source unit 10 also has, as refrigerant pipes, a suction pipe 11a, a discharge pipe 11b, a first gas refrigerant pipe 11c, a liquid refrigerant pipe 11d, and a second gas refrigerant pipe 11e (see FIG. 1). The suction pipe 11 a connects the flow direction switching mechanism 14 and the suction side of the compressor 12 . The discharge pipe 11 b connects the discharge side of the compressor 12 and the flow direction switching mechanism 14 . The first gas refrigerant pipe 11 c connects the flow direction switching mechanism 14 and the gas side end of the heat source heat exchanger 16 . The liquid refrigerant pipe 11d connects the liquid side end of the heat source heat exchanger 16 and the liquid refrigerant communication pipe LP. A connecting portion between the liquid refrigerant pipe 11d and the liquid refrigerant communication pipe LP is provided with a first closing valve 13a. The first expansion valve 18 is provided in the liquid refrigerant pipe 11d. The second gas refrigerant pipe 11e connects the flow direction switching mechanism 14 and the gas refrigerant communication pipe GP. A second stop valve 13b is provided at the connecting portion between the second gas refrigerant pipe 11e and the gas refrigerant communication pipe GP.

(2-1-1) Compressor The compressor 12 is a device that draws in low-pressure gas refrigerant in the refrigeration cycle, compresses it in a compression mechanism (not shown), and discharges high-pressure gas refrigerant in the refrigeration cycle.

The compressor 12 is an inverter-controlled compressor.

A later-described controller 90 that controls the operation of the compressor 12 basically rotates the motor (not shown) of the compressor 12 at high speed when the air conditioning load is large, and rotates the motor of the compressor 12 at low speed when the air conditioning load is small. In other words, the controller 90 basically controls the current i (current value) supplied to the motor of the compressor 12 to be large when the air conditioning load is large, and controls the current i supplied to the motor of the compressor 12 to be small when the air conditioning load is small.

Further, the controller 90 controls the current i supplied to the motor of the compressor 12 to be equal to or less than the current threshold It. More specifically, the controller 90 controls the current i supplied to the motor of the compressor 12 to the current threshold It even when the current i larger than the current threshold It may be supplied to the motor of the compressor 12 in terms of the capacity required of the air conditioner 100 (in other words, the air conditioning load processed by the air conditioner 100).

Here, the current threshold It is a value equal to or less than the design maximum value Imax of the current of the compressor 12 . Also, the current threshold It is a value equal to or greater than the design minimum value Imin of the current of the compressor 12 . Preferably, the current threshold It is a value smaller than the design maximum value Imax of the current of the compressor 12 and a value larger than the design minimum value Imin of the current of the compressor 12 .

Here, the design maximum value Imax of the current is a value of current that is allowed to be supplied to the compressor 12, which is determined by the manufacturer of the air conditioner 100 or the like. For example, although not limited, the design maximum value Imax of the current is the rated current value of the compressor 12 or a value obtained by multiplying the rated current value of the compressor 12 by a predetermined safety factor. The design minimum current value Imin is the minimum current value supplied to the compressor 12 determined by the manufacturer of the air conditioner 100 or the like.

The reason why the controller 90 controls the current i of the compressor 12 to be equal to or less than the current threshold value It will be described with reference to FIG. FIG. 7 is a conceptual graph showing the relationship between the capacity of the air conditioner 100 and the COP (coefficient of performance) of the air conditioner 100. As shown in FIG. As can be seen from FIG. 7, the COP of the air conditioner 100 is maximized when the capacity is at a predetermined value, and gradually deteriorates as the capacity increases beyond the predetermined value.

The capacity of the air conditioner 100 basically increases as the current i supplied to the motor of the compressor 12 increases. Therefore, when the air-conditioning load is large, increasing the current i supplied to the motor of the compressor 12 makes it easier to quickly achieve the target state (in this embodiment, the state in which the temperature of the air-conditioned space of the air conditioner 100 reaches the target temperature). However, when the current i supplied to the motor of the compressor 12 is increased to increase the capacity of the air conditioner 100, the COP (coefficient of performance) of the air conditioner 100 deteriorates as shown in the graph of FIG. Therefore, in the air conditioner 100, the controller 90 controls the current i supplied to the motor of the compressor 12 to be equal to or less than the current threshold value It in order to suppress deterioration of the energy consumption rate.

Note that the controller 90 , which will be described later, appropriately changes the current threshold value It used for controlling the compressor 12 . A change in the current threshold value It will be described later.

(2-1-2) Flow Direction Switching Mechanism The flow direction switching mechanism 14 is a mechanism that switches the flow direction of the refrigerant in the refrigerant circuit C according to the operation mode (cooling operation mode/heating operation mode) of the air conditioner 100 . The flow direction switching mechanism 14 is a four-way switching valve.

In the cooling operation mode, the flow direction switching mechanism 14 switches the flow direction of the refrigerant in the refrigerant circuit C so that the refrigerant discharged from the compressor 12 is sent to the heat source heat exchanger 16 . Specifically, in the cooling operation mode, the flow direction switching mechanism 14 communicates the suction pipe 11a with the second gas refrigerant pipe 11e and the discharge pipe 11b with the first gas refrigerant pipe 11c (see the solid line in FIG. 1). In the cooling operation mode, the heat source heat exchanger 16 functions as a condenser and the utilization heat exchanger 32 functions as an evaporator.

In the heating operation mode, the flow direction switching mechanism 14 switches the flow direction of the refrigerant in the refrigerant circuit C so that the refrigerant discharged from the compressor 12 is sent to the heat utilization heat exchanger 32 . Specifically, in the heating operation mode, the flow direction switching mechanism 14 communicates the suction pipe 11a with the first gas refrigerant pipe 11c and the discharge pipe 11b with the second gas refrigerant pipe 11e (see the broken line in FIG. 1). In the heating operation mode, the heat source heat exchanger 16 functions as an evaporator, and the utilization heat exchanger 32 functions as a condenser.

Note that the flow direction switching mechanism 14 may be realized without using the four-way switching valve. For example, the flow direction switching mechanism 14 may be configured by combining a plurality of electromagnetic valves and pipes so as to switch the flow direction of the refrigerant as described above.

(2-1-3) Heat Source Heat Exchanger The heat source heat exchanger 16 functions as a refrigerant condenser during cooling operation, and functions as a refrigerant evaporator during heating operation. Although not limited, the heat source heat exchanger 16 is, for example, a fin-and-tube heat exchanger having a plurality of heat transfer tubes and a plurality of heat transfer fins.

(2-1-4) First Expansion Valve The first expansion valve 18 is a mechanism for decompressing the refrigerant and adjusting the flow rate of the refrigerant. In this embodiment, the first expansion valve 18 is an electronic expansion valve whose opening is adjustable. The degree of opening of the first expansion valve 18 is appropriately adjusted according to the operating conditions. The first expansion valve 18 is not limited to an electronic expansion valve, and may be another type of expansion valve such as a thermostatic expansion valve.

(2-1-5) First fan The first fan 20 is a blower that generates an air flow that flows into the heat source unit 10 from the outside of the heat source unit 10, passes through the heat source heat exchanger 16, and then flows out of the heat source unit 10. The first fan 20 is, for example, an inverter-controlled fan.

(2-1-6) First Closing Valve and Second Closing Valve The first closing valve 13a is a valve provided at the connecting portion between the liquid refrigerant pipe 11d and the liquid refrigerant communication pipe LP. The second shut-off valve 13b is a valve provided at the connecting portion between the second gas refrigerant pipe 11e and the gas refrigerant communication pipe GP. The first shut-off valve 13a and the second shut-off valve 13b are manual valves. The first shut-off valve 13a and the second shut-off valve 13b are opened when the air conditioner 100 is in use.

(2-1-7) Discharge Pressure Sensor The discharge pressure sensor 24 is a sensor for measuring the discharge pressure Pd of the compressor 12 . In this embodiment, the discharge pressure sensor 24 is a pressure sensor provided in the discharge pipe 11b.

A sensor for measuring the discharge pressure Pd of the compressor 12 is not limited to a pressure sensor. For example, the sensor for measuring the discharge pressure Pd of the compressor 12 may be a temperature sensor that measures the condensation temperature in the refrigeration cycle. For example, during heating operation, a temperature sensor provided in the utilization heat exchanger 32 functioning as a condenser may be used as a sensor for measuring the discharge pressure Pd of the compressor 12 . The controller 90, which will be described later, can calculate the discharge pressure Pd of the compressor 12 from the condensation temperature by storing the relational expression between the condensation temperature and the pressure in the storage section of the controller 90. FIG.

(2-1-8) First Control Section The first control section 22 controls operations of various devices of the heat source unit 10 . The first control unit 22 mainly includes a microcontroller unit (MCU) and various electric circuits and electronic circuits (not shown). The MCU includes a CPU, memory, I/O interfaces, and the like. Various programs for the CPU of the MCU to execute are stored in the memory of the MCU. Various functions of the first control unit 22 do not need to be realized by software, and may be realized by hardware or by cooperation between hardware and software.

The first controller 22 is electrically connected to various devices of the heat source unit 10 including the compressor 12, the flow direction switching mechanism 14, the first expansion valve 18 and the first fan 20 (see FIG. 1). The first controller 22 is also electrically connected to various sensors provided in the heat source unit 10 including the discharge pressure sensor 24 . Although not limited, the sensors provided in the heat source unit 10 may include a temperature sensor provided in the discharge pipe 11b, a temperature sensor and pressure sensor provided in the suction pipe 11a, a temperature sensor provided in the heat source heat exchanger 16 and the liquid refrigerant pipe 11d, a temperature sensor for measuring the temperature of the heat source air, and the like. However, the heat source unit 10 need not have all of these sensors.

The first control unit 22 is communicably connected to the centralized operation device 50 via a communication line. The centralized operating device 50 is a device capable of centrally operating and stopping the heat source unit 10 and the plurality of utilization units 30 . Also, the centralized operation device 50 is a device capable of setting the scheduled operation of the air conditioner 100 .

The first controller 22 is connected to the second controllers 38 of the plurality of usage units 30 via communication lines. The first control unit 22 and the second control unit 38 exchange various signals via a communication line. The first control unit 22 and the second control unit 38 cooperate to function as a controller 90 that controls the operation of the air conditioner 100 . Functions of the controller 90 will be described later.

(2-2) Usage Unit The usage unit 30 will be described.

The utilization unit 30 blows out the air heat-exchanged with the refrigerant flowing through the utilization heat exchanger 32 to the air-conditioned space. The usage unit 30 is, for example, a ceiling installation type that is installed on the ceiling of the space to be air-conditioned. The usage unit 30 of the present embodiment is a ceiling-mounted air conditioning indoor unit. The ceiling-embedded air conditioning indoor unit includes a ceiling cassette type air conditioning indoor unit in which at least part of the air conditioning indoor unit is arranged in the ceiling space, and a duct connection type air conditioning indoor unit in which the entire air conditioning indoor unit is arranged in the ceiling space and a duct is connected. The type of the usage unit 30 is not limited to the ceiling-embedded type, and may be a ceiling-suspended type. Also, the type of the usage unit 30 may be a wall-mounted type, a floor-mounted type, or other type other than the ceiling-mounted type.

The utilization unit 30 mainly includes a utilization heat exchanger 32, a second expansion valve 34, a second fan 36, a suction temperature sensor 35, and a second controller 38, as shown in FIG.

The utilization unit 30 also has a liquid refrigerant pipe 37a and a gas refrigerant pipe 37b connected to the utilization heat exchanger 32 as refrigerant pipes (see FIG. 1). The liquid refrigerant pipe 37 a connects the liquid refrigerant communication pipe LP and the liquid side of the heat utilization heat exchanger 32 . A second expansion valve 34 is provided in the liquid refrigerant pipe 37a. The gas refrigerant pipe 37 b connects the gas refrigerant communication pipe GP and the gas side of the heat utilization heat exchanger 32 .

(2-2-1) Indoor Heat Exchanger In the utilization heat exchanger 32, heat is exchanged between the refrigerant flowing through the utilization heat exchanger 32 and the air. The utilization heat exchanger 32 is, for example, but not limited to, a fin-and-tube heat exchanger having a plurality of heat transfer tubes and a plurality of heat transfer fins.

One end of the utilization heat exchanger 32 is connected to a liquid refrigerant pipe 37a as shown in FIG. A gas refrigerant pipe 37b is connected to the other end of the utilization heat exchanger 32 as shown in FIG. During cooling operation, the refrigerant flows into the utilization heat exchanger 32 from the liquid refrigerant pipe 37a, and the refrigerant heat-exchanged with the air in the utilization heat exchanger 32 flows out from the gas refrigerant pipe 37b. During heating operation, the refrigerant flows into the utilization heat exchanger 32 from the gas refrigerant pipe 37b, and the refrigerant that has exchanged heat with the air in the utilization heat exchanger 32 flows out from the liquid refrigerant pipe 37a.

The utilization heat exchanger 32 functions as a refrigerant evaporator during cooling operation, and functions as a refrigerant condenser during heating operation.

(2-2-2) Second Expansion Valve The second expansion valve 34 is a mechanism for decompressing the refrigerant and adjusting the flow rate of the refrigerant. In this embodiment, the second expansion valve 34 is an electronic expansion valve whose opening is adjustable. The degree of opening of the second expansion valve 34 is appropriately adjusted according to the operating conditions. The second expansion valve 34 is not limited to an electronic expansion valve, and may be another type of expansion valve such as a thermostatic expansion valve.

(2-2-3) Second Fan The second fan 36 is a blower that generates an air flow that flows from the air-conditioned space into the utilization unit 30, passes through the utilization heat exchanger 32, and then blows out into the air-conditioned space. The first fan 20 is, for example, an inverter-controlled fan.

(2-2-4) Suction Temperature Sensor The suction temperature sensor 35 is a sensor that measures the temperature of the air (suction temperature Ti) taken into the usage unit 30 from the air-conditioned space. In other words, the intake temperature sensor 35 is a sensor that measures the temperature of the air-conditioned space.

(2-2-5) Second Control Unit The second control unit 38 controls operations of various devices of the usage unit 30 . The second control unit 38 has a microcontroller unit (MCU) and various electric circuits and electronic circuits (not shown). The MCU includes a CPU, memory, I/O interfaces, and the like. Various programs for the CPU of the MCU to execute are stored in the memory of the MCU. Various functions of the second control unit 38 do not need to be realized by software, and may be realized by hardware or by cooperation between hardware and software.

The second controller 38 is electrically connected to various devices of the utilization unit 30 including the second expansion valve 34 and the second fan 36 (see FIG. 1). Also, the second control unit 38 is electrically connected to the intake temperature sensor 35 . Furthermore, the second control section 38 is electrically connected to a sensor (not shown) provided in the usage unit 30 . The sensors (not shown) include, but are not limited to, temperature sensors provided in the utilization heat exchanger 32 and the liquid refrigerant pipes 37a.

The second control unit 38 is communicably connected to the centralized operation device 50 via a communication line. In addition, the second control unit 38 of each usage unit 30 is communicably connected to a remote controller for operating the air conditioner 100 (not shown), which is capable of operating and stopping the usage unit 30, setting a target temperature, etc., via a communication line.

The second controller 38 of each usage unit 30 is connected to the first controller 22 of the heat source unit 10 via a communication line. The first control unit 22 and the second control unit 38 cooperate to function as a controller 90 that controls the operation of the air conditioner 100 .

(2-3) Controller The controller 90 will be explained. Some or all of the various functions of the controller 90 described below may be executed by a control device provided separately from the first control section 22 and the second control section 38 .

The controller 90 has a storage unit (not shown) that stores programs to be executed by the CPU of the controller 90 and various types of information used to control the operation of the air conditioner 100 .

The CPU of the controller 90 executes a program stored in the storage unit, so that the controller 90 controls the operation of each unit of the air conditioner 100 during cooling operation and heating operation.

For example, the controller 90 controls the operation of the flow direction switching mechanism 14 so that the heat source heat exchanger 16 functions as a refrigerant condenser and the utilization heat exchanger 32 functions as a refrigerant evaporator during cooling operation. Further, the controller 90 controls the operation of the flow direction switching mechanism 14 so that the heat source heat exchanger 16 functions as a refrigerant evaporator and the utilization heat exchanger 32 functions as a refrigerant condenser during heating operation.

Further, the controller 90 controls the rotation speed of the motor of the compressor 12 according to the air conditioning load during cooling operation and heating operation. In other words, the controller 90 controls the current i supplied to the motor of the compressor 12 during cooling operation and heating operation. The controller 90 increases the current i supplied to the motor of the compressor 12 when the air conditioning load is large. On the other hand, the controller 90 controls the electric current i supplied to the motor of the compressor 12 to be small when the air conditioning load is small. When the air-conditioning load is large, for example, when there are many operating user units 30 and the difference between the actual temperature of the air-conditioned space and the target temperature (set temperature) is large. When the air conditioning load is small, for example, when the number of operating usage units 30 is small and the difference between the actual temperature of the air-conditioned space and the target temperature is small. The controller 90 controls the current i supplied to the motor of the compressor 12 as described above so that it is equal to or less than the current threshold value It stored in the storage unit. by the controller 90; A change in the current threshold value It will be described later.

In addition, the controller 90 adjusts the rotation speed of the motors of the first fan 20 and the second fan 36 and the opening degrees of the first expansion valve 18 and the second expansion valve 34 based on the measured values of various sensors (temperature sensor and pressure sensor), the target temperature of the air-conditioned space, and the like during the cooling operation and the heating operation. Various control modes are generally known for controlling the number of rotations of the motors of the first fan 20 and the second fan 36 during the cooling operation and the heating operation, and the opening degrees of the first expansion valve 18 and the second expansion valve 34. Therefore, the description is omitted here to avoid complication.

(3) Current Threshold Change Processing The current threshold It change processing by the controller 90 will be described.

Before describing the changing process, the reason for performing the changing process of the current threshold value It will be described with a specific example.

Here, an example will be described in which the controller 90 performs the cooling operation and the heating operation of the air conditioner 100 based on the schedule operation setting input to the centralized operation device 50 . In the air conditioner 100 that performs scheduled operation, the controller 90 starts the operation of the heat source unit 10 and the plurality of usage units 30 at the operation start time of the scheduled operation set using the centralized operation device 50 . Also, the controller 90 terminates the operation of the heat source unit 10 and the plurality of utilization units 30 at the operation end time of the scheduled operation set using the centralized operation device 50 .

The operation start time of the scheduled operation is set, for example, as follows. For example, assume that the air conditioner 100 is installed in an office building. In this case, the scheduled operation start time is set to a time that is earlier than the time when the person working in the office building starts working by a predetermined time (eg, 15 minutes, although this is not a limitation).

For example, when the user sets a time (schedule) to start using the air-conditioned space for the centralized operation device 50, the controller 90 starts operating the air conditioner 100 a predetermined time earlier than the set schedule. In other words, when the user sets the time to start using the air-conditioned space for the centralized operation device 50, the controller 90 sets the operation start time of the scheduled operation to be earlier than the set time by a predetermined time.

Alternatively, the user may directly input to the centralized operation device 50 a schedule operation start time that is a predetermined time earlier than the time at which the air-conditioned space is to be used.

In scheduled operation, the reason why the air conditioner 100 starts operating earlier than the time when people start using the air-conditioned space (in the above example, the work start time) is for precooling and preheating. Here, pre-cooling means a cooling operation for lowering the temperature of the air-conditioned space, which rises while the air conditioner 100 is stopped, so that the temperature of the air-conditioned space is adjusted to the target temperature at the time when people actually use the air-conditioned space. Preheating means a heating operation for raising the temperature of the air-conditioned space, which has decreased while the air conditioner 100 is stopped, so that the temperature of the air-conditioned space is adjusted to the target temperature at the time when people actually use the air-conditioned space.

Note that in the air conditioner 100 that performs scheduled operation, the air conditioning load during precooling and preheating is particularly large compared to after precooling and preheating. This is because the air conditioner 100 is normally stopped from the operation end time of the scheduled operation to the operation start time of the next scheduled operation, so that the temperature of the air-conditioned space and the target temperature tend to deviate relatively greatly at the operation start time of the scheduled operation.

In precooling and preheating, it is desired that the temperature of the air-conditioned space reaches the target temperature by the time a person starts using the air-conditioned space. From this point of view, it is preferable that the motor of the compressor 12 is supplied with a current i that is as large as possible. In other words, the current threshold It is preferably set to a value as large as possible. However, if a large value is adopted for the current threshold It and the capacity of the air conditioner 100 is made too large, the air conditioner 100 may be operated under poor COP conditions as shown in FIG.

On the other hand, from the viewpoint of energy saving, the value of the current i supplied to the motor of the compressor 12 is preferably limited to a range in which a relatively high COP can be maintained. In other words, the current threshold It is preferably set to a relatively small value. However, in this case, since the capacity of the air conditioner 100 is kept low, the temperature of the air-conditioned space may not reach the target temperature even when the person starts using the air-conditioned space. In this case, the user's comfort using the air-conditioned space may be reduced. Note that if precooling or preheating is started sufficiently early with respect to the time when a person starts using the air-conditioned space, such a situation may be avoided even if the current threshold It is set to a relatively small value. However, in this case, the cooling operation and heating operation of the air-conditioned space where there is no person will be performed for a long time, which is not preferable from the viewpoint of energy saving.

Therefore, in the air conditioner 100, it is desired that the temperature of the air-conditioned space can be adjusted to the target temperature at the time when a person starts using the air-conditioned space without taking an excessively long precooling time, and the compressor 12 is operated under conditions that can suppress the energy consumption. In order to achieve this, in the air conditioner 100, the controller 90 performs processing to change the current threshold value It to adjust the current threshold value It to an appropriate value.

The process of changing the current threshold value It by the controller 90 will be described below.

Note that the controller 90 controls the current i of the compressor 12 to be equal to or less than the current threshold value It stored in the storage section of the controller 90 . Therefore, the controller 90 changes the current threshold It to be used by rewriting the value of the current threshold It stored in the storage unit.

<Setting of current threshold at power-on for air conditioner 100>
First, the setting of the current threshold value It when the air conditioner 100 is powered on will be described.

When the air conditioner 100 is powered on, the controller 90 sets the current threshold It stored in the storage unit to a predetermined initial value _I0 . In other words, when the air conditioner ₁₀₀ is powered on, the controller 90 controls the current i of the compressor 12 to be equal to or less than the current threshold It (initial value I0 ₎ , with a predetermined initial value I0 as the current threshold It. It should be noted that the time when the air conditioner 100 is powered on includes the time when the power is first turned on after the air conditioner 100 is installed in the building. Further, when the air conditioner 100 is powered on, for example, it includes the time when the breaker of the distribution board that supplies power to the air conditioner 100 is turned off once and then turned on again.

It should be noted that the initial value _I0 is preferably a relatively large value. Although not limited, the initial value _I0 is, for example, 80 to 100% of the design maximum value Imax. By using such a relatively large initial value _I0 , for example, when the air conditioner 100 is operated for the first time after installation or when a long period of time has passed since the air conditioner 100 was operated last time, the occurrence of a state in which the temperature of the air-conditioned space never reaches the target temperature tends to be suppressed.

Note that the current threshold value It stored in the storage unit at the start of operation of the air conditioner 100 may be used as it is, except when the air conditioner 100 is powered on.

<Current threshold change processing>
The controller 90 executes, in parallel, the following four types of current threshold It changing processes (referred to as first to fourth changing processes).

By performing the first to fourth changing processes of the current threshold It and optimizing the current threshold It, for example, it is possible to suppress the occurrence of a situation in which the rise time of the air conditioner 100 exceeds the target time, and suppress the occurrence of a situation in which the rise time becomes excessively short relative to the target time and the power consumption of the compressor increases. As a specific example, it is possible to optimize the pre-cooling and pre-heating times in the scheduled operation, and avoid the situation where the temperature of the air-conditioned space does not reach the target temperature even when the time to start using the air-conditioned space, and the situation where the pre-cooling and pre-heating time is excessively shortened and the air conditioner 100 is operated under poor conditions of COP where the capacity is higher than necessary.

As a premise of the process of changing the current threshold It, the controller 90 continuously monitors the value of the current i supplied to the motor of the compressor 12 .

(a) First change process for current threshold The first change process for the current threshold It is, roughly speaking, a process for increasing the value of the current threshold It when the time during which the compressor 12 is operated with the current i at the current threshold It is longer than the first time T1. The first change processing of the current threshold It will be described with reference to the flowchart of FIG.

As a premise of the first change processing of the current threshold It, the controller 90 measures the time during which the compressor 12 is continuously operated at the current threshold It.

Note that the time during which the compressor 12 is operated at the current threshold It means a state in which the current i supplied to the motor of the compressor 12 can be controlled to be greater than the current threshold It from the viewpoint of the air conditioning load, but the current i is suppressed to the current threshold It.

Further, in this specification, the time during which the compressor 12 is continuously operated at the current threshold It substantially means the time during which the compressor 12 is continuously operated at the current threshold It. For example, even if the current i supplied to the compressor 12 deviates from the current threshold It for a short period of time (for example, several seconds), if the current is generally constant at the current threshold It as a whole, it is defined that the compressor 12 is continuously operated at the current threshold It.

The first change process of the current threshold value It of the controller 90 is started when the operation of the air conditioner 100 is started (step S1).

In the first change process, the controller 90 performs a process of determining whether or not the time during which the compressor 12 is continuously operated at the current threshold It is longer than or equal to the first time T1 (step S2). Although not limited, the first time T1 is, for example, 15 minutes.

Note that if the controller 90 is configured to start operating the air conditioner 100 a predetermined time earlier than the set schedule when a schedule (for example, the start time of use of the air-conditioned space) is set for the centralized operation device 50, it is preferable to set the first time T1 to the predetermined time for the following reasons.

As described above, the air conditioning load during precooling and preheating that is performed when scheduled operation is started tends to be larger than at other timings. Therefore, the state in which the compressor 12 is continuously operated at the current threshold It is particularly likely to occur during precooling or preheating. Therefore, by changing the value of the current threshold It so that the time during which the compressor 12 is continuously operated at the current threshold It does not exceed the first time T1 by the first change processing, the start-up of the refrigeration cycle apparatus is likely to be completed within the time of the precooling operation or the preheating operation, in other words, by the time when the air-conditioned space starts to be used.

For the same reason, even when the user directly inputs the operation start time of the scheduled operation into the centralized operation device 50, it is preferable to match the first time T1 with the time difference between the operation start time of the scheduled operation and the time at which the space to be air-conditioned is started to be used.

When it is determined that the time during which the compressor 12 is operated at the current threshold value It is equal to or longer than the first time period T1, the process proceeds to step S3. On the other hand, when it is determined that the time during which the compressor 12 is operated at the current threshold It is shorter than the first time T1, or when the compressor 12 is not operated at the current threshold It, the process proceeds to step S6.

In step S3, the controller 90 determines whether or not the current threshold It is the design maximum value Imax. When the current threshold value It is the design maximum value Imax, the process proceeds to step S4. On the other hand, if the current threshold It is not the design maximum value Imax, the process proceeds to step S4.

In step S4, the controller 90 changes the current threshold It. Specifically, the controller 90 increases the current threshold It by a predetermined value α.

The value of α is preferably 1-4% of the design maximum value Imax of the compressor 12 current. In this embodiment, the value of α is 2% of the design maximum value Imax. By using such a value α, it is possible to suppress the occurrence of a state in which the change in the current threshold It is insufficient, or a state in which the change in the current threshold It is too large and the current threshold It needs to be changed in the opposite direction (hunting).

The changed current threshold It is stored in the storage unit. As a result, the controller 90 controls the current i of the compressor 12 to be equal to or less than the changed current threshold It.

Next, in step S5, the controller 90 resets the clock for the first change process. In short, the controller 90 newly starts timing the time during which the compressor 12 is continuously operated at the current threshold It. After that, the process proceeds to step S6.

In step S6, it is determined whether or not a condition for terminating the operation of the air conditioner 100 is satisfied. The condition for terminating the operation of the air conditioner 100 is, for example, that the centralized operation device 50 is operated to stop the operation of the air conditioner 100 . Further, the condition for ending the operation of the air conditioner 100 is, for example, that the operation end time of the scheduled operation comes. If the operation end condition is not satisfied, the process returns to step S2. If the operation end condition is satisfied, the first change process ends.

(b) Second change process for current threshold The second change process for the current threshold It is, roughly speaking, a process for changing the value of the current threshold It to the initial value _I0 when the current i of the compressor 12 is operated at the current threshold It longer than the third time T3. Note that the third time T3 is longer than the first time T1. For example and without limitation, the first time T1 is 15 minutes while the third time T3 is 45 minutes.

The main purpose of the second change processing of the current threshold It is to quickly resolve the situation when the current threshold It is set to a value significantly smaller than the optimum current threshold It for some reason, and to ensure the performance of the air conditioner 100.

Here, the second change process of the current threshold It has priority over the first change process of the current threshold It. In other words, here, when the condition for changing the current threshold It by the second changing process and the condition for changing the current threshold It by the first changing process are satisfied at the same time, only the current threshold It is changed by the second changing process.

The second change processing of the current threshold It will be described with reference to the flowchart of FIG.

As a prerequisite for the second change process of the current threshold It, the controller 90 measures the time during which the compressor 12 is continuously operated at the current threshold It, separately from the time for the first change process of the current threshold It. Therefore, even when the clocking is reset in step S5 of the first changing process of the current threshold It, the clocking for the second changing process of the current threshold It may be continued. Specifically, when the current i supplied to the motor of the compressor 12 is the changed current threshold It after the current threshold It is increased in step S4 of the first change process of the current threshold It, the timing for the second change process of the current threshold It is continued.

Immediately after the current threshold It is raised, the current i supplied to the motor of the compressor 12 may fall below the current threshold It for a short period of time (for example, several seconds). However, even in such a case, the controller 90 determines that the current i of the compressor 12 is continuously operated at the current threshold It, and continues the timing for the second changing process of the current threshold It.

The second change process of the current threshold value It of the controller 90 is started when the operation of the air conditioner 100 is started (step S11).

In the second change process, the controller 90 performs a process of determining whether or not the time during which the compressor 12 is continuously operated at the current threshold It is longer than or equal to the third time T3 (step S12). When it is determined that the compressor 12 is operated at the current threshold value It is equal to or longer than the third time period T3, the process proceeds to step S13. On the other hand, if it is determined that the time during which the compressor 12 is operated at the current threshold It is shorter than the third time T3, or if the compressor 12 is not operated at the current threshold It, the process proceeds to step S15.

In step S13, the controller 90 changes the current threshold It. Specifically, the controller 90 changes the current threshold It to the initial value _I0 . The changed current threshold It is stored in the storage unit. As a result, the controller 90 performs control so that the current i of the compressor 12 is equal to or less than the changed current threshold It (initial value I ₀ ).

The effect of changing the current threshold value It to the initial value Io in step S13 will be described.

Determining in step S12 that the compressor 12 has been continuously operated at the current threshold It for the third time T3 or longer means that the temperature of the air-conditioned space has not reached the target temperature even though the compressor 12 has been operated at the current threshold It for a long time. In this case, it is assumed that the current threshold It is too low. Therefore, in step S13, the controller 90 does not raise the current threshold It step by step (for example, 1 to 4% of the design maximum value Imax of the current of the compressor 12), but raises it all at once to the initial value _I0 . As a result, even when the air conditioner 100 has not been used for a long time and the season has changed since the previous operation, or even in an irregular environment (for example, when the temperature has changed significantly from the previous day), the temperature of the air-conditioned space can be quickly reached to the target temperature.

Next, in step S14, the controller 90 resets the clock for the second change process. In short, the controller 90 newly starts timing the time during which the compressor 12 is continuously operated at the current threshold It. After that, the process proceeds to step S15.

In step S15, it is determined whether or not a condition for terminating the operation of the air conditioner 100 is satisfied. Examples of conditions for ending operation of the air conditioner 100 are as described above. If the operation end condition is not satisfied, the process returns to step S12. If the operation termination condition is satisfied, the second change processing is terminated.

(c) Current Threshold Third Change Processing The third change processing of the current threshold It is, roughly speaking, a process of lowering the value of the current threshold It when the time during which the current i of the compressor 12 is operated at the current threshold It is longer than the second time T2. The third change processing of the current threshold It will be described with reference to the flowchart of FIG.

As a prerequisite for the third change processing of the current threshold value It, the controller 90 measures the elapse of a predetermined period with a timer. As a premise of the third change processing of the current threshold value It, the controller 90 counts the integrated time during which the compressor 12 is operated at the current threshold value It.

In the third change process, the controller 90 repeatedly performs the process of determining whether a predetermined period of time has elapsed after starting the third change process at a predetermined timing (step S21). Although not limited, the predetermined period is, for example, 24 hours. Further, for example, when the controller 90 has grasped the operation start time of the scheduled operation (in other words, when the controller 90 has grasped the start time of precooling or preheating), the controller 90 may determine in step S21 whether a predetermined time (for example, one hour) has elapsed from the scheduled operation start time. Further, for example, when the controller 90 knows the operation start time and the operation end time of the scheduled operation, the controller 90 may determine that the predetermined period is from the operation start time to the operation end time. If it is determined in step S21 that the predetermined period has passed, the process proceeds to step S22.

In step S22, the controller 90 determines whether the accumulated time during which the compressor 12 is operated at the current threshold It during the predetermined period is shorter than the second time T2. Although not limited, the second time T2 is, for example, 15 minutes. When it is determined that the accumulated time during which the compressor 12 has been operated at the current threshold It during the predetermined period is less than the second time T2, the process proceeds to step S23. On the other hand, if it is determined that the accumulated time during which the compressor 12 has been operated at the current threshold It during the predetermined period is equal to or longer than the second time T2, the process proceeds to step S25.

In step S23, the controller 90 determines whether or not the current threshold It is the design minimum value Imin. If the current threshold It is the design minimum value Imin, the process proceeds to step S25. On the other hand, if the current threshold It is not the design minimum value Imin, the process proceeds to step S24.

In step S24, the controller 90 changes the current threshold It. Specifically, the controller 90 lowers the current threshold It by a predetermined value β. The value of β is preferably 1-4% of the design maximum value Imax of the compressor 12 current. In this embodiment, the value of β is 2% of the design maximum value Imax. Note that the value of β and the value of α in the first change process of the current threshold value It may be the same value or different values. The changed current threshold It is stored in the storage unit. As a result, the controller 90 controls the current i of the compressor 12 to be equal to or less than the changed current threshold It.

Next, in step S25, the controller 90 resets the counting of the integrated time for the third change process, and ends the third change process. Note that when the predetermined period is 24 hours, the controller 90 immediately starts the next third change process after the end of the third change process, and newly starts counting the integrated time during which the compressor 12 is operated at the current threshold It.

Here, it is assumed that the air conditioner 100 is operated every day. If there is a day on which the air conditioner 100 has not been operated during the predetermined period in step S21, the third change process of the current threshold value It may be prevented from being performed on that day.

(d) Fourth Change Processing of Current Threshold The fourth change processing of the current threshold It is, roughly speaking, a process of increasing the value of the current threshold It when the temperature of the object to be temperature-controlled deviates from the target temperature even when the compressor 12 is operated at the current i of the current threshold It.

Although not limited, here, the fourth change process of the current threshold It has priority over the first change process of the current threshold It. In other words, here, when the condition for changing the current threshold It by the fourth changing process and the condition for changing the current threshold It by the first changing process are satisfied at the same time, only the current threshold It is changed by the fourth changing process. However, the present invention is not limited to this, and if a condition for changing the current threshold It by the fourth change process and a condition for changing the current threshold It by the first change process are satisfied at the same time, the change of the current threshold It by the first change process and the change of the current threshold It by the fourth change process may be performed at the same time.

Specifically, the controller 90 increases the current threshold by a first value γ1 when the temperature condition of the air-conditioned space to be temperature-controlled deviates from the target condition by a first reference or more while the compressor 12 is being operated at the current threshold It continues for the first reference time Ts1. Further, when the compressor 12 is operated at the current threshold It, the current threshold is increased by a second value γ2 smaller than the first value γ1 when the temperature condition of the air-conditioned space deviates from the target condition by a second reference smaller than the first reference or more for a second reference time Ts2.

More specifically, when the compressor 12 is operated at the current threshold value It, the controller 90 increases the current threshold value It by a first value γ1 when the difference between the intake temperature Ti in the utilization unit 30 as the temperature condition of the air-conditioned space and the target temperature as the target condition is greater than the first temperature difference A as the first reference and continues for the first reference time Ts1. Further, when the compressor 12 is operated at the current threshold value It, the controller 90 increases the current threshold value It by a second value γ2 when the difference between the suction temperature Ti in the utilization unit 30 and the target temperature is greater than or equal to a second temperature difference B serving as a second reference, which is smaller than the first temperature difference A, and continues for the second reference time Ts2. The difference between the intake temperature Ti in the utilization unit 30 and the target temperature as the target condition is expressed by (Ti-Tit) during cooling operation and by (Tit-Ti) during heating operation.

Preferably, the controller 90 increases the current threshold value It by the first value γ1 when even one of the plurality of utilization units 30 in operation continues to be in a state where the difference between the suction temperature Ti and the target temperature as the target condition is greater than or equal to the first temperature difference A for the first reference time Ts1. Further, preferably, the controller 90 increases the current threshold value It by a second value γ2 when even one utilization unit 30 in which the difference between the suction temperature Ti and the target temperature as the target condition deviates from the suction temperature Ti and the target temperature serving as the target condition by the second temperature difference B or more continues for the second reference time Ts2 among the plurality of utilization units 30 in operation.

The fourth change processing of the current threshold It will be described with reference to the flowchart of FIG.

In the following description of the fourth change processing of the current threshold It, which is performed with reference to FIG. 6, the difference between the intake temperature Ti and the target temperature means the largest value among the differences between the intake temperature Ti and the target temperature in the plurality of operating utilization units 30.

As a premise of the fourth change processing of the current threshold It, the controller 90 continuously monitors the time change of the difference between the suction temperature Ti and the target temperature.

The fourth change process of the current threshold value It of the controller 90 is started when the operation of the air conditioner 100 is started (step S41).

In the fourth change process for the current threshold It, the controller 90 determines whether the compressor 12 is being operated at the current threshold It (step S42). If the compressor 12 is being operated at the current threshold value It, the process proceeds to step S43. If the compressor 12 is not operated at the current threshold It, the process proceeds to step S55.

In step S43, the controller 90 determines whether or not the state in which the difference between the intake temperature Ti and the target temperature is greater than or equal to the first temperature difference A continues for the first reference time Ts1. For example, without limitation, the first temperature difference A is 5° C. and the first reference time Ts1 is 5 minutes. If the difference between the intake temperature Ti and the target temperature continues for the first temperature difference A or more for the first reference time Ts1, the process proceeds to step S44.

In step S44, the controller 90 determines whether or not the current threshold value It is the design maximum value Imax. If the current threshold It is the design maximum value Imax, the process proceeds to step S55. On the other hand, if the current threshold It is not the design maximum value Imax, the process proceeds to step S45.

In step S45, the controller 90 determines whether the air conditioner 100 is in heating operation (whether the refrigeration cycle device is in heating operation). If the heating operation is being performed, the process proceeds to step S46, and if the heating operation is not being performed, the process proceeds to step S47.

In step S46, the controller 90 determines whether or not the discharge pressure Pd of the compressor 12 acquired by the discharge pressure sensor 24 is lower than the target discharge pressure Pdt during heating operation stored in the storage unit. When the discharge pressure Pd is lower than the target discharge pressure Pdt, the process proceeds to step S47, and when the discharge pressure Pd is the target discharge pressure Pdt, the process proceeds to step S55. In short, here, the process of increasing the current threshold value It is performed only when the capacity of the air conditioner 100 can be increased.

In step S47, the controller 90 changes the current threshold It. Specifically, the controller 90 increases the current threshold It by a predetermined value γ1. The value of γ1 is preferably 1-4% of the design maximum value Imax of the compressor 12 current. In this embodiment, the value of γ1 is 4% of the design maximum value Imax. The changed current threshold It is stored in the storage unit. As a result, the controller 90 controls the current i of the compressor 12 to be equal to or less than the changed current threshold It.

Next, in step S48, the controller 90 resets the timing for the fourth change process. In short, the controller 90 newly starts timing for the fourth change process of the current threshold It. After that, the process proceeds to step S55.

In step S49, the controller 90 determines whether or not the state in which the difference between the intake temperature Ti and the target temperature is greater than or equal to the second temperature difference B continues for the second reference time Ts2. For example, without limitation, the second temperature difference B is 3° C. and the second reference time Ts2 is 10 minutes.

Note that the first reference time Ts1 and the second reference time Ts2 may be the same time. However, by setting the first reference time Ts1 to be shorter than the second reference time Ts2, it is easy to quickly eliminate the difference between the intake temperature Ti and the target temperature when the difference is large.

If the state in which the difference between the intake temperature Ti and the target temperature continues for the second temperature difference B or more for the second reference time Ts2, the process proceeds to step S50.

In step S50, the controller 90 determines whether or not the current threshold value It is the design maximum value Imax. If the current threshold It is the design maximum value Imax, the process proceeds to step S55. On the other hand, if the current threshold It is not the design maximum value Imax, the process proceeds to step S51.

At step S51, the controller 90 determines whether the air conditioner 100 is in heating operation. If the heating operation is being performed, the process proceeds to step S52, and if the heating operation is not being performed, the process proceeds to step S53.

In step S52, the controller 90 determines whether or not the discharge pressure Pd of the compressor 12 acquired by the discharge pressure sensor 24 is lower than the target discharge pressure Pdt during heating operation stored in the storage unit. When the discharge pressure Pd is lower than the target discharge pressure Pdt, the process proceeds to step S53, and when the discharge pressure Pd is the target discharge pressure Pdt, the process proceeds to step S55.

In step S53, the controller 90 changes the current threshold It. Specifically, the controller 90 increases the current threshold It by a predetermined value γ2. The value of γ2 is preferably 1-4% of the design maximum value Imax of the compressor 12 current. Also, the value of γ2 is a value smaller than γ1 in step S46. Preferably, the value of γ1 is 1.5-3 times the value of γ2. In this embodiment, the value of γ2 is 2% of the design maximum value Imax.

Next, in step S54, the controller 90 resets the timing for the fourth change process. In short, the controller 90 newly starts timing for the fourth change process of the current threshold It. After that, the process proceeds to step S55.

In step S55, it is determined whether or not a condition for terminating the operation of the air conditioner 100 is satisfied. Examples of conditions for ending operation of the air conditioner 100 are as described above. If the operation end condition is not satisfied, the process returns to step S42. If the operation end condition is satisfied, the fourth change process ends.

It should be noted that the flowcharts of the first to fourth change processes of the current threshold value It described here are merely examples and can be changed as appropriate. For example, the order of processing steps in each flow chart may be changed as appropriate within a consistent range. Also, for example, the processing steps in each flowchart may be executed simultaneously within a consistent range.

Further, for example, processing steps in each flowchart may be omitted as appropriate within a consistent range. For example, the determinations of steps S45, S46, S51, and S52 in the fourth change process of the current threshold value It may be omitted.

(4) Specific Examples of Current and Current Threshold Time Changes Specific examples of time change of the current i of the compressor 12 and the current threshold It in the air conditioner 100 will be described with reference to FIGS. 8 and 9 . FIG. 8 is a diagram conceptually showing an example of temporal changes in the current i and the current threshold It when the set current threshold It is too low. FIG. 9 is a diagram conceptually showing an example of temporal changes in the current i and the current threshold It when the set current threshold It is too large.

(4-1) When the current threshold value is too low Referring to FIG. 8, a specific example of changes over time in the current i and the current threshold It of the compressor 12 when the current threshold It initially stored in the storage unit is too low.

Here, it is assumed that the current threshold It stored in the storage unit when the air conditioner 100 starts operating is 64% of the design maximum value Imax of the current of the compressor 12 (position (1) in FIG. 8). Also, the initial value _I0 of the current threshold It is assumed to be 80% of the design maximum value Imax of the current of the compressor 12 . Further, here, it is assumed that the air conditioner 100 is stopped for a long time before the operation of the air conditioner 100 is started, and the difference between the intake temperature Ti at the start of the operation of the air conditioner 100 and the target temperature is greater than 5°C.

On this premise, when the operation of the air conditioner 100 is started, the controller 90 executes a first change process, a second change process, and a fourth change process of the current threshold It. The controller 90 also executes a third change process for the current threshold It (here, since it is assumed that the value of the current threshold It is too low, the third change process for the current threshold It will not be particularly described).

Here, since the air conditioning load is large, it is assumed that the current i of the compressor 12 reaches the current threshold value It after the start of operation.

Here, it is assumed that the difference between the suction temperature Ti and the target temperature is 5° C. (first temperature difference A) or more when the operation at the current threshold It continues for 5 minutes (first reference time Ts1). Therefore, the process of step S<b>47 of the fourth change process is performed, and the controller 90 increases the current threshold It by 4% of the design maximum value Imax of the current of the compressor 12 . As a result, the current threshold It becomes 68% of the design maximum value Imax of the current of the compressor 12 (position (2) in FIG. 8).

Here, even after setting the current threshold It to 68% of the design maximum value Imax of the current of the compressor 12, the air conditioning load is still large, and the current i of the compressor 12 is assumed to be the changed current threshold It. However, in this state, it is assumed that the difference between the suction temperature Ti and the target temperature is less than 5° C. when the operation at the current threshold It continues for 5 minutes after the current threshold It is changed. On the other hand, it is assumed that the difference between the intake temperature Ti and the target temperature is 3° C. (second temperature difference B) or more when the operation at the current threshold It continues for 10 minutes (second reference time Ts2) after changing the current threshold It. Therefore, the process of step S53 of the fourth change process of the current threshold It is performed, and the controller 90 increases the current threshold It by 2% of the design maximum value Imax of the current of the compressor 12 . As a result, the current threshold It becomes 70% of the design maximum value Imax of the current of the compressor 12 (position (3) in FIG. 8).

Here, even after setting the current threshold It to 70% of the design maximum value Imax of the current of the compressor 12, the air conditioning load is still large, and the current i of the compressor 12 is assumed to be the changed current threshold It. However, in this state, it is assumed that the difference between the suction temperature Ti and the target temperature is less than 3° C. when the operation at the current threshold It continues for 10 minutes after the current threshold It is changed. On the other hand, assume that the operation at the current threshold It continues for 15 minutes (first time T1) after the change in the current threshold It. Therefore, the process of step S<b>4 of the first change process of the current threshold It is performed, and the controller 90 increases the current threshold It by 2% of the design maximum value Imax of the current of the compressor 12 . As a result, the current threshold It becomes 72% of the design maximum value Imax of the current of the compressor 12 (position (4) in FIG. 8).

Here, even after setting the current threshold It to 72% of the design maximum value Imax of the current of the compressor 12, the air conditioning load is still large, and the current i of the compressor 12 becomes the current threshold It after the change. Then, it is assumed that the operation of the compressor 12 at the current threshold It continues for 45 minutes (third time T3) after the current i first reaches the current threshold It (64% of the design maximum value Imax) at that time. Therefore, the process of step S13 of the second change process of the current threshold It is performed, and the controller 90 sets the current threshold It to the initial value I ₀ (80% of the design maximum value Imax, position (5) in FIG. 8).

Here, even after setting the current threshold It to 80% of the design maximum value Imax of the current of the compressor 12, the air conditioning load is still large, and the current i of the compressor 12 is assumed to be the changed current threshold It. However, the current i becomes equal to or less than the current threshold It in less than 15 minutes (first time T1) after the current threshold It is changed. Therefore, the current threshold It is not changed here.

(4-2) When the current threshold value is too low Referring to FIG. 9, a specific example of changes over time in the current i and the current threshold It of the compressor 12 when the current threshold It initially stored in the storage unit is too large.

Here, it is assumed that the current threshold It stored in the storage unit when the air conditioner 100 starts operating is 64% of the design maximum value Imax of the current of the compressor 12 (position (1) in FIG. 9). Also, the initial value _I0 of the current threshold It is assumed to be 80% of the design maximum value Imax of the current of the compressor 12 . Also, here, it is assumed that the air conditioning load of the air conditioner 100 is relatively low.

On this premise, when the operation of the air conditioner 100 is started, the controller 90 executes a first change process, a second change process, and a fourth change process of the current threshold It. The controller 90 also executes a third change process for the current threshold It.

Here, it is assumed that the air conditioning load is small and the current i of the compressor 12 once reaches the current threshold value It after the start of operation, but becomes smaller than the current threshold value It in less than 5 minutes. Then, it is assumed that the current i of the compressor 12 does not reach the current threshold value It for a predetermined period of time (for example, 24 hours) even in the subsequent operation.

In this case, the cumulative operating time of the compressor 12 at the current threshold It during the predetermined period is shorter than 15 minutes ((second time T2), so the process of step S24 of the third change process of the current threshold It is performed, and the controller 90 lowers the current threshold It by 2% of the design maximum value Imax of the current of the compressor 12. As a result, the current threshold It is 62% of the design maximum value Imax of the current of the compressor 12 ((2 in FIG. 9) ) position).

(5) Features (5-1)
The air conditioner 100 of the above embodiment includes a compressor 12 and a controller 90 . The controller 90 controls the current i of the compressor 12 to be equal to or less than the current threshold It. The controller 90 changes the current threshold It based on the time during which the compressor 12 is operated at the current threshold It.

In the air conditioner 100 of the above embodiment, the current threshold value It is changed according to the time during which the compressor 12 is operated at the current threshold value It. Therefore, the air conditioner 100 optimizes the current threshold It, suppresses the rise time of the air conditioner 100 from becoming longer, and suppresses the occurrence of a situation in which the rise time becomes excessively short with respect to the target time and the power consumption at the start of operation increases.

(5-2)
In the air conditioner 100 of the above-described embodiment, the controller 90 raises the current threshold It when the time during which the compressor 12 is operated at the current threshold It is longer than the first time T1.

In the air conditioner 100 of the above-described embodiment, control is performed to raise the current threshold It when the time period during which the compressor 12 is operated at the current threshold It is longer than the first time T1, so that the startup time of the air conditioner 100 becomes too long.

(5-3)
In the air conditioner 100 of the above embodiment, the controller 90 raises the current threshold It when the time during which the compressor 12 is continuously operated at the current threshold It is longer than the first time T1.

In the air conditioner 100 of the above-described embodiment, the current threshold It is controlled to increase when the compressor 12 is continuously operated at the current threshold It for a period longer than the predetermined time. Therefore, when the current threshold It is too small, it is easy to quickly improve this.

(5-4)
In the air conditioner 100 of the above embodiment, the controller 90 lowers the current threshold It when the accumulated time during which the compressor 12 is operated at the current threshold It during the predetermined period is shorter than the second time T2.

In the air conditioner 100 of the above-described embodiment, when the accumulated time during which the compressor 12 is operated at the current threshold It in the predetermined period is shorter than the second time T2, control is performed to lower the current threshold It. Therefore, it is possible to suppress the occurrence of a situation in which the startup time of the air conditioner 100 becomes too short and the power consumption increases.

(5-5)
In the air conditioner 100 of the above embodiment, the controller 90 controls the compressor 12 to start operating the air conditioner 100 a first time T1 earlier than the set schedule.

In the air conditioner 100 of the above-described embodiment, power consumption can be suppressed while operating so that the start-up of the air conditioner 100 is completed within the pre-cooling operation or pre-heating operation time when the scheduled operation is performed.

(5-6)
In the air conditioner 100 of the above embodiment, the controller 90 changes the current threshold It by 1 to 4% of the design maximum value Imax of the current i of the compressor 12 when changing the current threshold It.

In the air conditioner 100 of the above-described embodiment, it is possible to suppress the occurrence of a state in which the change in the current threshold It is insufficient, or a state in which the change in the current threshold It is too large and the current threshold It needs to be changed in the opposite direction (hunting).

(5-7)
In the air conditioner 100 of the above-described embodiment, the controller 90 controls the current of the compressor 12 to be equal to or less than the current threshold It, using a predetermined initial value _I0 as the current threshold It when the air conditioner 100 is powered on.

An appropriate value for the current threshold It changes, for example, between a season with a large load and a season with a small load. Therefore, when the air conditioner 100 is not used for a long period of time and the use is resumed after some time has passed since the previous use, the value that was appropriate as the current threshold It during the previous use may deviate greatly from the current appropriate value of the current threshold It. For example, if the current threshold It is excessively small relative to an appropriate value at the time of resumption of use, there is a risk that the temperature of the object to be temperature-adjusted does not reach the target temperature for a long period of time at the start of operation.

On the other hand, in the air conditioner 100 of the above-described embodiment, a predetermined initial value _I0 is used as the current threshold It when the power is turned on. Therefore, if a relatively large value is adopted as the initial value _I0 , it is possible to suppress the occurrence of a situation in which the temperature of the object to be temperature-adjusted does not reach the target temperature for a long period of time at the start of operation.

(5-8)
In the air conditioner 100 of the above-described embodiment, the controller 90 changes the current threshold It to the initial value _I0 when the time during which the compressor 12 is operated at the current threshold It is longer than the third time T3.

In the air conditioner 100 of the above-described embodiment, the current threshold It can be returned to the initial value _I0 when the compressor 12 is operated at the current threshold It for a long period of time, in other words, when the value of the current threshold It is too small. Therefore, if a relatively large value is adopted as the initial value _I0 , it is possible to suppress the occurrence of a situation in which the temperature of the object to be temperature-adjusted does not reach the target temperature for a long period of time.

(6) Modifications The above embodiment can be appropriately modified as shown in the following modifications. Each modification may be applied in combination with other modifications as long as there is no contradiction.

(6-1) Modification A
In the above embodiment, it is preferable that all of the first to fourth change processes of the current threshold value It are executed. However, it is not limited to this, and part of it may not be executed.

For example, when the first change process of the current threshold It is performed, the fourth change process of the current threshold It may not be performed. And vice versa.

Further, for example, the second change processing of the current threshold value It may not be executed.

(6-2) Modification B
In the above-described embodiment, in the fourth change process of the current threshold It, the amount of increase in the current threshold It is set to a different value depending on whether the difference between the intake temperature Ti and the target temperature is greater than the first temperature difference A or greater than the second temperature difference B. However, the present invention is not limited to this. For example, the same value may be used for the first value γ1 and the second value γ2 while setting the first reference time Ts1 in the fourth change process of the current threshold It to be shorter than the second reference time Ts2.

(6-3) Modification C
In the above embodiment, in the fourth change process of the current threshold It, different processes are performed depending on whether the difference between the intake temperature Ti and the target temperature is greater than the first temperature difference A or the second temperature difference B or more. However, it is not limited to this.

For example, in the fourth change process of the current threshold It, when the compressor 12 is operated at the current threshold It, the difference between the suction temperature Ti and the target temperature is compared with a single threshold, and if the difference between the suction temperature Ti and the target temperature and the threshold continues for a predetermined time, the current threshold It is increased by a predetermined amount.

(6-4) Modification D
In the above-described embodiment, the controller 90 performs the process of increasing the current threshold It when the time during which the compressor 12 is continuously operated at the current threshold It is longer than the first time T1.

Alternatively, or in addition to this, the controller 90 may perform a process of increasing the current threshold It when the accumulated time during which the compressor 12 is operated at the current threshold It is longer than a predetermined time during a predetermined period (for example, within 24 hours).

(6-5) Modification E
In the above embodiment, the controller 90 sets the current threshold It to the initial value _I0 when the power of the air conditioner 100 is turned on, but it is not limited to this. For example, when the power of the air conditioner 100 is turned on other than the first time, the current threshold value It stored in the storage unit may be used as it is.

<Appendix>
Although embodiments of the present disclosure have been described above, it will be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the present disclosure as set forth in the appended claims.

INDUSTRIAL APPLICABILITY The present disclosure is widely applicable and useful to refrigeration cycle devices.

12 compressor 90 controller (control unit)
100 air conditioner (refrigeration cycle device)
Imax Design maximum value It Current threshold

JP 2009-243814 A

Claims (4)

a compressor (12);
a control unit (90) for controlling the current of the compressor to be equal to or less than the current threshold (It);
A refrigeration cycle device comprising:
The control unit changes the current threshold based on the time the compressor is operated at the current threshold,
The control unit increases the current threshold when the time during which the compressor is continuously operated at the current threshold is longer than a first time,
The control unit controls the compressor so as to start operation of the refrigeration cycle device earlier than the set schedule by the first time.
Refrigeration cycle equipment. a compressor (12);
a control unit (90) for controlling the current of the compressor to be equal to or less than the current threshold (It);
with
The control unit changes the current threshold based on the time the compressor is operated at the current threshold,
The control unit lowers the current threshold when the accumulated time during which the compressor is operated at the current threshold during a predetermined period is shorter than a second time.
Refrigeration cycle equipment. When the refrigeration cycle apparatus is first used, the control unit controls the current of the compressor to be equal to or less than the current threshold, with a predetermined initial value as the current threshold;
The control unit changes the current threshold to the initial value when the time during which the compressor is operated at the current threshold is longer than a third time that is longer than the first time.
The refrigeration cycle apparatus according to claim 1 . When the power of the refrigeration cycle device is turned on, the control unit controls the current of the compressor to be equal to or less than the current threshold, with a predetermined initial value as the current threshold.
The refrigeration cycle device according to claim 1 or 2 .

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