Air conditioning system and control method

Abstract

To provide an air conditioning system.SOLUTION: An air conditioning system 1 is configured by connecting an indoor unit 10, an outdoor unit 20, and an operation device 40 having a management function. The outdoor unit 20 includes a compressor 21 having a compressor-motor 21a, an inverter 30 for applying a current to the compressor-motor 21a, one or more temperature sensors 31, 33, and a controller 26 for controlling the normal preheat of the compressor 21. In response to an operation command via the operation device 40, the control device 26 applies a current for heat generation to the compressor-motor 21a via the inverters 30 on the basis of the detection values of the one or more temperature sensors 31, 33 so that the amount of heat generation is larger than that in the normal preheat, thereby executing the rapid preheat of the compressors 21 and executing control for shifting to an operation in which the compressors 21 operate.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an air conditioning system and a method for controlling the air conditioning system.

Background Art

[0002] In an air conditioning system, the time when the compressor is in a standby state tends to be longer than the time when the compressor is operating. When the outside air temperature is around 14 to 22 degrees, neither cooling nor heating is performed, and it often enters a complete operation stop state. For example, in an air conditioning system for a store, the standby time when the compressor is not operating accounts for more than 50% of the annual hours in Tokyo. There is a great demand for reducing the power consumption in the standby state of this air conditioning system, that is, the standby power.

[0003] When the operation of the air conditioning system stops and the compressor temperature drops, the liquid refrigerant dissolves in the refrigeration oil enclosed in the compressor, and the viscosity of the refrigeration oil decreases. If the compressor is started in this state, the sliding part of the compressor may wear and be damaged. Therefore, before starting the operation of the air conditioning system, it is necessary to heat the compressor to a predetermined temperature, that is, to perform preheating. Most of the above-mentioned standby power is the preheating input of this compressor.

[0004] From the viewpoint of compressor reliability, it is sufficient if a predetermined compressor temperature is maintained when the compressor is started. On the other hand, from the viewpoint of user convenience, it is desirable to enable the air conditioning system to be used at any time. Conventionally, control has been performed to always maintain a predetermined compressor temperature even during the period when the compressor is stopped. For this reason, the energization time becomes longer than necessary, and the standby power increases, which is not sufficient.

[0005] Regarding the reduction of power consumption due to preheating during the above standby time, Japanese Patent Application Laid-Open No. 2016-142496 (Patent Document 1) is known. Patent Document 1 discloses an air conditioner in the case where a plurality of compressors equipped with crankcase heaters are provided. In the prior art of Patent Document 1, an air conditioning management device sets an operation schedule of the air conditioner, and when it comes to the operation stop time, it transmits an operation stop command to an outdoor unit control unit to stop the operation of the air conditioner. Then, when the time until the next operation start is equal to or longer than a predetermined time, the air conditioning load is predicted based on the outside air temperature, and control is performed so as to increase or decrease the number of compressors to which power is supplied to the crankcase heater. When an operation command is made during that time, only the compressors whose compressor temperature is equal to or higher than a predetermined temperature, that is, the operation is controlled to start in a state where the capacity is limited by the number of compressors that cannot immediately start operation.

[0006] In the above prior art, when a plurality of compressors are provided, it is possible to reduce standby power while corresponding to an operation command. However, in an air conditioning system having one compressor, the number of energized units cannot be increased or decreased, and there is a limitation on the number of compressors in the applicable system. Therefore, when the limitation on the number of compressors cannot be satisfied, even with the prior art, in order to immediately start operation in response to an operation command outside the operation schedule, it is still necessary to always execute control to maintain a predetermined compressor temperature, which is not sufficient from the viewpoint of increasing standby power.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present disclosure has been made in view of the above prior art, and an object of the present disclosure is to provide an air conditioning system capable of achieving both rapid start of operation in response to an off-schedule operation command and reduction of standby power as compared with the case of executing control to always maintain a predetermined compressor temperature without any restriction on the number of compressors, and a control method for the air conditioning system.

Means for Solving the Problems

[0009] In the present disclosure, in order to solve the above problems, an air conditioning system having the following features is provided, in which an outdoor unit, an indoor unit, and an operating device having a management function are connected. In this air conditioning system, the outdoor unit includes a compressor having a compressor motor, an inverter that applies current to the compressor motor, one or more temperature sensors, and a control device that controls normal preheating of the compressor. The control device, in response to an operation command via the operating device, applies a current for heat generation to the compressor motor via the inverter so that the heating amount is larger than the normal preheating based on the detected value of one or more temperature sensors, thereby performing rapid preheating of the compressor and executing control to shift to an operation in which the compressor operates.

[0010] In the present disclosure, further, a control method for an air conditioning system in which an outdoor unit, an indoor unit, and an operating device having a management function are connected is provided. Here, the outdoor unit includes a compressor having a compressor motor, an inverter that applies current to the compressor motor, one or more temperature sensors, and a control device that controls normal preheating of the compressor. In the control method, the control device performs a step of detecting an operation command via the operating device, a step of performing rapid preheating of the compressor by applying a current for heat generation to the compressor motor via the inverter so that the heating amount is larger than the normal preheating based on the detected value of one or more temperature sensors in response to detecting the operation command, and a step of shifting to an operation in which the compressor operates.

Advantages of the Invention

[0011] With the above configuration, it becomes possible to achieve both a quick start of operation in response to an operation command outside the schedule and a reduction in standby power compared to the case of performing control to always maintain a predetermined compressor temperature, without any restrictions on the number of compressors.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments of the present invention are not limited to the specific embodiments described below. In the drawings, the same reference numerals indicate the same or corresponding parts.

[0014] The present disclosure is directed to an air conditioning system and a method for controlling the air conditioning system. In the air conditioning system according to an embodiment of the present invention, an outdoor unit, an indoor unit, and an operating device having a management function are connected. The outdoor unit includes a compressor having a compressor motor, an inverter that applies current to the compressor motor, one or more temperature sensors, and a control device that controls normal preheating of the compressor. The control device responds to an operation command via the operating device, and based on the detection values of the one or more temperature sensors, applies a current for heat generation to the compressor motor via the inverter so that the heating amount is larger than the normal preheating, thereby performing rapid preheating of the compressor and executing control to shift to an operation in which the compressor operates.

[0015] With the above configuration, by heating the compressor with an output larger than the normal preheating and reaching a predetermined compressor temperature in a shorter time than the normal preheating, the operation can be started immediately in response to an operation command. Further, the frequency of compressor heating during the period when the compressor is stopped can be suppressed to once immediately before the start of operation, and standby power can be reduced. As a result, it is possible to achieve both the rapid start of operation in response to an operation command outside the schedule and the reduction of standby power compared with the case of executing control to always maintain a predetermined compressor temperature without any restrictions on the number of compressors.

[0016] In a preferred embodiment, the outdoor unit includes a crankcase heater. The control device adjusts the output by combining heating of the compressor by energizing the crankcase heater and heating of the compressor by applying current to the compressor motor via the inverter based on the detection values of the one or more temperature sensors, and performs rapid preheating. With this configuration, when the detection values of the one or more temperature sensors indicate that the compressor preheating requires a larger amount of heat, the control device can more surely and quickly reach a predetermined compressor temperature by using the heating of the compressor by energizing the crankcase heater in combination.

[0017] In a preferred embodiment, the outdoor unit is provided with a blower, and when performing rapid preheating with the compressor stopped, the control device controls to drive the blower to generate convection and cool the inverter. More preferably, the driving of the blower by the control device may be executed in response to the temperature of the inverter reaching a predetermined temperature or higher during the execution of rapid preheating. With this configuration, it is possible to prevent overheating of the inverter during rapid preheating and maintain the reliability of the air conditioner system.

[0018] In a preferred embodiment, when an operation schedule time is set, the control device calculates the required time for heating the compressor based on the detection values of one or more temperature sensors, and starts heating the compressor at a time corresponding to the operation schedule time and the required time for heating the compressor, and controls to execute normal preheating by the operation schedule time. With this configuration, when an operation schedule time is set, it is possible to complete preheating by the scheduled time and start operation.

[0019] In a specific embodiment, normal preheating utilizes heat generation by applying current to the compressor motor via an inverter, heat generation by energizing a crankcase heater, or both.

[0020] In a preferred embodiment, rapid preheating is executed so that the compressor temperature reaches a predetermined threshold temperature within a shorter time than normal preheating with the compressor stopped.

[0021] In a preferred embodiment, the one or more temperature sensors include an outdoor air temperature sensor that measures the outdoor air temperature and a compressor temperature sensor that measures the temperature of the compressor.

[0022] Also, in one or more embodiments, the control device may control to execute the above-described normal preheating at a frequency corresponding to the detection values of one or more temperature sensors, or periodically, or irregularly.

[0023] In one or more embodiments, the operation device may be a remote controller connected to an indoor unit or an operation device connected to an outdoor unit.

[0024] According to another embodiment, a control method for an air conditioning system in which an outdoor unit, an indoor unit, and an operation device having a management function are connected is provided. The outdoor unit includes a compressor having a compressor motor, an inverter that applies current to the compressor motor, one or more temperature sensors, and a control device that controls normal preheating of the compressor. In the control method, the control device detects an operation command via the operation device, and in response to detecting the operation command, applies a current for heat generation to the compressor motor via the inverter so that the heating amount is larger than the normal preheating based on the detection value of one or more temperature sensors, thereby performing rapid preheating of the compressor, and then shifts to an operation in which the compressor operates.

[0025] With the above configuration, by heating the compressor with an output larger than the normal preheating and reaching a predetermined compressor temperature in a shorter time than the normal preheating, the operation can be started immediately in response to the operation command. Further, the frequency of compressor heating during the period when the compressor is stopped can be suppressed to once immediately before the start of operation, and standby power can be reduced. As a result, it is possible to achieve both the rapid start of operation in response to an operation command outside the schedule and the reduction of standby power compared to the case of performing control to always maintain a predetermined compressor temperature without any restrictions on the number of compressors.

[0026] In a preferred embodiment, the outdoor unit includes a crankcase heater. In the control method, when the control device executes rapid preheating, based on the detected values of one or more temperature sensors, it further executes a step of adjusting the output by combining heating of the compressor by energizing the crankcase heater and heating of the compressor by applying current to the compressor motor via an inverter. With this configuration, when the detected values of one or more temperature sensors indicate that compressor preheating is required with a larger amount of heat, the control device can more reliably reach a predetermined compressor temperature by using heating of the compressor by energizing the crankcase heater in combination.

[0027] In a preferred embodiment, the outdoor unit includes a blower. In the control method, when performing rapid preheating with the compressor stopped, in order to cool the inverter, the control device further executes a step of generating convection by driving the blower. In a more preferred embodiment, the step of driving the blower may be executed in response to the temperature of the inverter reaching a predetermined temperature or higher during the execution of rapid preheating. With this configuration, it is possible to prevent overheating of the inverter during rapid preheating and maintain the reliability of the air conditioner system.

[0028] In a preferred embodiment, when an operation schedule time is set, the control device executes a step of calculating the required time for compressor heating based on the detected values of one or more temperature sensors, and a step of starting heating of the compressor so as to execute normal preheating until the operation schedule time in response to the arrival of the time corresponding to the operation schedule time and the calculated required time for compressor heating. With this configuration, when the operation schedule time is set, it is possible to complete preheating by the scheduled time and start operation.

[0029] Hereinafter, with reference to FIGS. 1 to 4, the air conditioner system 1 according to the embodiment of the present invention will be described more specifically.

[0030] FIG. 1 is a schematic diagram showing an air conditioning system 1 including one or more indoor units 10 and an outdoor unit 20 according to an embodiment of the present invention. The air conditioning system 1 is a device that performs air conditioning by circulating a refrigerant in a refrigeration cycle (heat pump cycle). As shown in FIG. 1, the air conditioning system 1 includes one or more indoor units 10 (10a, 10b...) installed in each indoor (air-conditioned space) and an outdoor unit 20 installed outdoors.

[0031] In FIG. 1, two indoor units 10a and 10b are shown as a plurality of indoor units 10. However, the number of indoor units 10 is not particularly limited, and it may be one or three or more. Also, the number of outdoor units 20 can be preferably applied when there is one, but it is not necessarily limited to one.

[0032] One or more indoor units 10 and the outdoor unit 20 are connected via a refrigerant pipe 2. The air conditioning system 1 may include an operating device such as a remote controller for communicating with the indoor unit 10 wirelessly or wiredly and operating the indoor unit 10 in the room where the indoor unit 10 is installed.

[0033] In the example shown in FIG. 1, the air conditioning system 1 shows an embodiment of a multi-split air conditioner for buildings including an outdoor unit 20 of an upward-blowing type as an example. However, in the embodiments of the present invention, the form of the air conditioning system 1 is not particularly limited.

[0034] FIG. 2 is a diagram showing a configuration example of the air conditioning system 1 according to an embodiment of the present invention. Each indoor unit 10 and the outdoor unit 20 are connected by two pipes 2a and 2b through which a refrigerant as a heat medium circulates. As the refrigerant, for example, hydrofluorocarbons such as R410a and R32 are used. Also, the indoor unit 10 and the outdoor unit 20 are connected by a communication line to communicate with each other. Note that the indoor unit 10 and the outdoor unit 20 are not limited to being wired-connected by a communication line, and may be wirelessly connected.

[0035] During operation, the indoor unit 10 takes in indoor air, exchanges heat between the taken-in air and the refrigerant supplied from the outdoor unit 20, blows out the cooled air or the warmed air, and cools or warms the interior to the set temperature. For this purpose, the indoor unit 10 includes an indoor heat exchanger 11 that exchanges heat between the indoor air and the refrigerant, and an indoor fan 12 that takes in the indoor air into the indoor heat exchanger 11 and blows out the air heat-exchanged by the indoor heat exchanger 11.

[0036] The indoor unit 10 includes a room temperature sensor 13 that detects the indoor temperature in order to notify the outdoor unit 20 of the indoor temperature. Further, the indoor unit 10 includes an indoor expansion valve 14 that expands the refrigerant and adjusts the flow rate of the refrigerant flowing through the indoor heat exchanger 11.

[0037] When the indoor unit 10 is used for cooling, the indoor heat exchanger 11 functions as an evaporator, and the refrigerant flows into the indoor heat exchanger 11 in a two-phase flow state (liquid refrigerant) in which liquid and gas are mixed. The refrigerant exchanges heat with the air taken in by the indoor fan 12 in the indoor heat exchanger 11, causing the liquid component to evaporate, and is discharged from the indoor heat exchanger 11 as gaseous refrigerant and sent to the outdoor unit 20.

[0038] The outdoor unit 20 is activated upon receiving a designation from the control device and starts operating in an operation mode set by an operation device such as a remote controller or other operating equipment. The operation modes include a cooling mode, a heating mode, a ventilation mode, etc. The outdoor unit 20 controls the temperature, pressure, flow rate, etc. of the refrigerant according to the set temperature, indoor temperature, pipe temperature, etc. Further, the outdoor unit 20 stops operating upon receiving a command from the control device.

[0039] The outdoor unit 20 is connected to one or more indoor units 10 (10a to 10c in FIG. 2) via pipes 2a and 2b, and circulates refrigerant. For this purpose, a compressor 21 for circulating the refrigerant is provided. The refrigerant gas compressed by the compressor 21 exchanges heat with the air taken in by the outdoor fan 23 in the outdoor heat exchanger 22, and becomes high-pressure liquid refrigerant. Further, the outdoor unit 20 is provided with a four-way valve 25 for reversing the direction in which the refrigerant flows in order to enable heating operation. The outdoor expansion valve 24 is provided to convert the refrigerant, which has become high-pressure during heating, into low-temperature and low-pressure refrigerant, and to adjust the refrigerant flow rate.

[0040] The flow rate of the refrigerant can be changed by varying the operating frequency of the compressor 21. When the operating frequency of the compressor 21 is increased, the refrigerant supply amount increases and the air conditioning capacity increases. Conversely, when the operating frequency of the compressor 21 is decreased, the refrigerant supply amount decreases and the air conditioning capacity decreases.

[0041] The outdoor unit 20 is provided with a control device 26 (hereinafter also referred to as the outdoor unit control device 26). The outdoor unit control device 26 is connected to an inverter for driving the motor of the compressor 21 and the motor of the outdoor fan 23. The outdoor unit control device 26 also controls the operating frequency of the compressor 21, the rotational speed of the outdoor fan 23, and the opening degree of the outdoor expansion valve 24 based on the indoor temperatures detected by the room temperature sensors 13a to 13c of the plurality of indoor units 10a to 10c, the set temperature, the pipe temperature detected by a sensor in the outdoor unit 20, and the operating mode. Further, the four-way valve 25 is switched according to the set operating mode. Detection values of temperatures detected by various sensors such as an outside air temperature sensor and a compressor temperature sensor are further input to the outdoor unit control device 26.

[0042] In the air conditioning system 1, when the operation stops and the temperature of the compressor 21 decreases, the liquid refrigerant dissolves in the refrigerating machine oil encapsulated in the compressor 21, and the viscosity of the refrigerating machine oil decreases. When the compressor 21 is started in this state, the sliding part of the compressor 21 may be worn and damaged. For this reason, before operating the air conditioning system 1, it is desirable to heat the compressor 21 to a predetermined temperature, that is, to perform preheating. This preheating input of the compressor 21 may account for a large amount in the power consumption during standby. From the viewpoint of the reliability of the compressor 21, it is sufficient if a predetermined compressor temperature is maintained when the compressor 21 is started. On the other hand, from the viewpoint of user convenience, it is desirable to enable the air conditioning system 1 to be used at any time.

[0043] Hereinafter, with reference to FIGS. 3 and 4, the preheating control executed by the air conditioning system 1 according to the embodiment of the present disclosure will be described.

[0044] FIG. 3 is a block diagram showing a functional configuration related to the preheating control of the air conditioning system 1 according to the embodiment of the present invention. FIG. 3 shows, in addition to the detailed configuration inside the outdoor unit 20 related to the preheating control, the indoor unit 10 connected to the outdoor unit 20, the operating device 40 connected to the outdoor unit 20, and the remote controller 50 connected to each indoor unit 10. Here, either one or both of the remote controller 50 and the operating device 40 constitute an operating device having a management function that receives an operation command from the user in the present embodiment.

[0045] The outdoor unit 20 includes a compressor 21, an outdoor fan (outdoor blower) 23, the above-described outdoor unit control device 26, an inverter 30, and one or more temperature sensors. The indoor unit 10, the outdoor unit 20, the operating device 40, and the remote controller 50 may each have an individual control circuit (control device). In the following description, the above-described outdoor unit control device 26 will be described as performing the preheating control of the present invention. In other embodiments, the preheating control according to the embodiment of the present invention may be performed by a control device other than the outdoor unit 20, or may be shared among the control devices of a plurality of devices.

[0046] FIG. 3 shows a compressor temperature sensor 31 and an outdoor air temperature sensor 33 as one or more temperature sensors included in the outdoor unit 20. The compressor temperature sensor 31 detects the temperature (compressor temperature) at a predetermined location of the compressor 21 and outputs the detected value of the compressor temperature to the outdoor unit control device 26. The outdoor air temperature sensor 33 detects the temperature of the outdoor air and outputs the detected value of the outdoor air temperature to the outdoor unit control device 26.

[0047] The compressor 21 has a compressor motor 21a, and the inverter 30 applies current to the compressor motor 21a included in the compressor 21 under the control of the outdoor unit control device 26. The outdoor unit control device 26 controls the normal preheating of the compressor 21 and controls the execution of rapid preheating according to the embodiment of the present disclosure.

[0048] In the described embodiment, the outdoor unit control device 26 executes a heating method in which the compressor 21 itself generates heat by applying current to the compressor motor 21a inside the compressor 21 (specifically, the motor coil constituting the compressor motor 21a) via the inverter 30. The outdoor unit control device 26 heats the compressor 21 while the air conditioning system 1 is stopped, that is, without rotating the compressor 21. In this heating method in which the compressor 21 itself generates heat, the applied current may be an alternating current (for example, a high-frequency current) or a direct current. For example, heat can be generated by utilizing eddy current (induced current) generated when an alternating current is applied, electric resistance, or Joule heat generated by a direct current.

[0049] For example, in the method of applying a high-frequency current, a PWM (Pulse Width Modulation) signal is generated at a frequency sufficiently higher than the operating range of the compressor 21. The PWM signal is converted into a voltage and applied to the compressor motor 21a of the compressor 21. A high-frequency current flows through the stator coil of the compressor motor 21a. Since this high-frequency current does not contain low-frequency components, it is possible to heat the compressor without generating vibrations or the like. The liquid refrigerant in the compressor 21 is heated by the heating of the compressor motor 21a. Note that when heating, the current may be applied to one phase, two phases, or all three phases.

[0050] The outdoor unit control device 26 applies a current to the compressor motor 21a according to the detected values of various temperature sensors, and heats the compressor 21 while the air conditioning system 1 is stopped. Further, the outdoor unit control device 26 can adjust the current value to be applied according to the detected values of various temperature sensors.

[0051] Here, normal preheating will be described. When the operation schedule time is set, the outdoor unit control device 26 calculates the required compressor heating time based on the detected values of the above one or more temperature sensors, more specifically, the compressor temperature sensor 31 and the outside air temperature sensor 33. The required compressor heating time is the time expected to be required until the compressor temperature (correlated with the temperature of the refrigerant oil) reaches a predetermined threshold temperature according to the temperature conditions at that time.

[0052] The outdoor unit control device 26 calculates the time to start preheating the compressor 21, the normal preheating start scheduled time, based on the set operation schedule time and the calculated required compressor heating time. The normal preheating start scheduled time is, simply, the time obtained by subtracting the required compressor heating time from the operation schedule time. When the normal preheating start scheduled time arrives, the outdoor unit control device 26 starts preheating the compressor 21 and controls it to execute normal preheating by the operation schedule time.

[0053] Here, rapid preheating in response to a user command outside the schedule will be described. The outdoor unit control device 26 responds to an operation command via the operation device 40 or the remote controller 50, and executes rapid preheating of the compressor 21 based on the detected values of one or more temperature sensors, more specifically, the compressor temperature sensor 31 and the outside air temperature sensor 33. The rapid preheating is realized by applying a current for heat generation to the compressor motor 21a via the inverter 30 so that the heating amount is larger than that of normal preheating. Then, after the rapid preheating is completed or after a predetermined upper limit time of the rapid preheating is reached, the outdoor unit control device 26 executes control to shift to a normal operation in which the compressor 21 operates. The rapid preheating is executed in a stopped state of the compressor 21 so that the compressor temperature reaches a predetermined threshold temperature within a shorter time than normal preheating.

[0054] When the above-described heating method is adopted, the inverter 30 itself may overheat due to the application of current. Therefore, in the embodiment to be described, the outdoor unit control device 26 further controls the outdoor fan 23 connected via the inverter 30, and can control to drive the outdoor fan 23 during normal preheating and rapid preheating in a state where the compressor 21 is stopped. By driving the outdoor fan 23, forced convection can be generated to cool the inverter 30. Preferably, a temperature sensor for detecting the temperature of the inverter 30 is provided, and forced convection by driving the outdoor fan 23 is executed in response to the detected value of the temperature of the inverter 30 by the temperature sensor becoming equal to or higher than a predetermined threshold during the execution of normal preheating or rapid preheating.

[0055] FIG. 4 is a flowchart showing a compressor preheating control method executed by the outdoor unit control device 26 of the air conditioning system 1 according to the embodiment of the present invention. Note that the preheating control is executed during the cooling operation and the heating operation. Therefore, hereinafter, it will be described assuming that either the cooling operation or the heating operation is performed. The control method shown in FIG. 4 starts from step S100. In step S101, the outdoor unit control device 26 determines whether there is an operation command. The operation command here includes an operation command outside the schedule from the user and an operation command according to the schedule.

[0056] In step S101, if it is determined that there is no operation command (NO), the control proceeds to step S102. In step S102, the outdoor unit control device 26 determines whether it is in normal preheating. In step S102, if it is determined that it is not in normal preheating (NO), the control proceeds to step S104.

[0057] In step S104, the outdoor unit control device 26 calculates the required time for compressor heating by normal preheating to raise the current temperature of the compressor 21 to a desired temperature based on the detected value from the compressor temperature sensor 31 and the detected value from the outside air temperature sensor 33. In step S105, the outdoor unit control device 26 calculates the scheduled start time of normal preheating to start normal preheating based on the pre-set schedule time and the calculated required time for compressor heating.

[0058] In step S106, it is determined whether the current time has reached the scheduled start time of normal preheating. In step S106, if it is determined that the current time is equal to or greater than the scheduled start time of normal preheating and has reached the scheduled start time of normal preheating (YES), the control proceeds to step S107. In step S107, the outdoor unit control device 26 starts normal preheating and the control returns to step S101. On the other hand, in step S106, if it is determined that the current time is less than the scheduled start time of normal preheating and has not reached the start time of normal preheating (NO), the control directly returns to step S101.

[0059] Referring again to step S102, if it is determined in step S102 that normal preheating is in progress (YES), the control proceeds to step S103. In step S103, the outdoor unit control device 26 determines whether the compressor temperature is equal to or higher than the threshold temperature. If it is determined in step S103 that the compressor temperature is lower than the threshold temperature (NO), the control returns to step S101. On the other hand, if it is determined in step S103 that the compressor temperature is equal to or higher than the threshold temperature (YES), the control proceeds to step S108. In step S108, the outdoor unit control device 26 stops the normal preheating and returns the control to step S101. Here, the threshold temperature is not particularly limited, but a value obtained by adding a predetermined temperature (for example, a value in the range of 10 degrees to 15 degrees) to the outside air temperature can be used.

[0060] Referring again to step S101, if it is determined in step S101 that there is an operation command (YES), the control proceeds to step S109. In step S109, the outdoor unit control device 26 determines whether the above operation command is in accordance with the schedule. If it is determined in step S109 that it is in accordance with the schedule (YES), the control proceeds to step S114 and shifts to normal operation (cooling operation if it is a cooling operation command, heating operation if it is a heating operation command).

[0061] On the other hand, if it is determined in step S109 that it is not in accordance with the schedule (NO), the control proceeds to step S110. When an operation command via the operation device by the user is detected, it is determined that it is not in accordance with the schedule. In step S110, the outdoor unit control device 26 determines whether the compressor temperature is equal to or higher than the threshold temperature. If it is determined in step S110 that the compressor temperature is equal to or higher than the threshold temperature (YES), the control proceeds to step S114 and shifts to normal operation.

[0062] On the other hand, in step S110, if it is determined that the compressor temperature is less than the threshold temperature (NO), the control proceeds to step S111. In step S111, the outdoor unit control device 26 starts rapid preheating and proceeds to step S112. The rapid preheating of the compressor 21 is executed by applying a current for heat generation to the compressor motor 21a via the inverter 30 so as to have a heating amount larger than that of normal preheating based on the detected values of one or more temperature sensors, more specifically, the detected values of the compressor temperature sensor 31 and the outside air temperature sensor 33. For example, when the detected value of the compressor temperature sensor 31 or the outside air temperature sensor 33 is low, the current can be applied so that the heating amount becomes large.

[0063] In step S112, the outdoor unit control device 26 determines whether the compressor temperature is equal to or higher than the threshold temperature or whether the threshold time has elapsed since the start of rapid preheating. This threshold time is set as the upper limit time of rapid preheating and is for cutting off the rapid preheating when it takes too much time for the compressor temperature to reach the threshold temperature even if the rapid preheating is continued.

[0064] In step S112, if the compressor temperature is less than the threshold temperature and the threshold time has not elapsed since the start of rapid preheating (NO), step S112 is looped and waiting for the condition to be satisfied. On the other hand, in step S112, if the compressor temperature is equal to or higher than the threshold temperature (YES), the control proceeds to step S113. Alternatively, in step S112, if the threshold time has elapsed since the start of rapid preheating (YES), the control proceeds to step S113.

[0065] In step S113, the outdoor unit control device 26 stops rapid preheating, proceeds to step S114, and shifts to the normal operation in which the compressor 21 operates.

[0066] According to the embodiments of the present disclosure described above, by heating the compressor 21 with an output greater than normal preheating and reaching a predetermined compressor temperature in a shorter time than normal preheating, the operation can be started immediately in response to an operation command via the operating device. Further, the frequency of heating the compressor 21 during the period when the compressor 21 is stopped can be suppressed to once immediately before the start of operation, and standby power can be reduced. As a result, it is possible to achieve both the rapid start of operation in response to an off-schedule operation command and the reduction of standby power as compared with the case of executing control to always maintain a predetermined compressor temperature without any restrictions on the number of compressors 21.

[0067] In the above-described embodiment, the heating method adopted both in normal preheating and rapid preheating is a heating method (hereinafter referred to as the motor heating method) in which a current is passed through the compressor 21 itself via the inverter 30 to generate heat. However, the embodiment is not necessarily limited to the above-described embodiment. In other embodiments, in normal preheating, instead of the motor heating method, another heating method may be adopted, or the motor heating method and another heating method may be used in combination. Similarly, in other embodiments, in rapid preheating, the motor heating method and another heating method may be used in combination.

[0068] Hereinafter, with reference to FIGS. 5 and 6, another embodiment in which the motor heating method and another heating method are used in combination in rapid preheating will be described. In the following, the differences from the embodiment described with reference to FIGS. 1 to 4 will be mainly described for another embodiment, and unless otherwise specified, the embodiment shown in FIGS. 5 and 6 has the same configuration as the embodiment described with reference to FIGS. 1 to 4.

[0069] The compressor 21 shown in FIG. 5 includes a crankcase heater 32 in addition to the compressor motor 21a and the compressor temperature sensor 31 as one or more temperature sensors provided in the outdoor unit 20. The crankcase heater 32 is an electric heater provided around the crankcase of the compressor 21 and is used to facilitate the separation of the refrigerant and the refrigerant oil in order to maintain the lubricity of the sliding portion in the compressor 21.

[0070] In other embodiments to be described, the crankcase heater 32 is used as a heating means that replaces the motor heating during normal preheating, or as a heating means used in combination with the motor heating. In other embodiments to be described, the crankcase heater 32 is also used as a heating means used in combination with the motor heating during rapid preheating.

[0071] The outdoor unit control device 26 adjusts the output by a combination of heating the compressor 21 by energizing the crankcase heater 32 (crank heater heating) and heating the compressor 21 by applying a current to the compressor motor 21a via the inverter 30 (motor heating) based on the detected values of one or more temperature sensors, more specifically, the detected values of the compressor temperature sensor 31 and the outside air temperature sensor 33, to perform rapid preheating. Also, for normal preheating, motor heating, crankcase heater heating, or both can be utilized.

[0072] FIG. 6 is a flowchart showing a compressor preheating control method executed by the outdoor unit control device 26 of the air conditioning system 1 according to another embodiment of the present invention. The control method shown in FIG. 6 starts from step S200. Steps S201 to S208 shown in FIG. 6 are generally common to steps S101 to S108 in the compressor preheating control method described with reference to FIG. 4.

[0073] The start of normal preheating in step S207 may be the same as step S107 in the embodiment described with reference to FIGS. 1 to 4, or may be performed only by crankcase heater heating, or the output may be adjusted by using both motor heating and crankcase heater heating according to the detected values of the compressor temperature sensor 31 and the outside air temperature sensor 33. In step S208, the outdoor unit control device 26 stops the normal preheating according to the mode of normal preheating. For example, when motor heating is being performed, the outdoor unit control device 26 stops applying current to the compressor motor 21a. When crankcase heater heating is being performed, the outdoor unit control device 26 stops energizing the crankcase heater 32.

[0074] In step S209, the outdoor unit control device 26 determines whether the above operation command is in accordance with the schedule. If it is determined in step S209 that it is in accordance with the schedule (YES), the control proceeds to step S216 and shifts to normal operation.

[0075] On the other hand, if it is determined in step S209 that it is not in accordance with the schedule (NO), the control proceeds to step S210. In step S210, the outdoor unit control device 26 determines whether the compressor temperature is equal to or higher than the threshold temperature. If it is determined in step S210 that the compressor temperature is equal to or higher than the threshold temperature (YES), since the temperature is already high enough, the control proceeds to step S216 and shifts to normal operation.

[0076] On the other hand, if it is determined in step S210 that the compressor temperature is lower than the threshold temperature (NO), the control proceeds to step S211. In step S211, the outdoor unit control device 26 determines the preheating conditions. The preheating conditions are conditions for determining whether to perform only motor heating or to use crankcase heater heating in combination during rapid preheating. The preheating conditions may be conditions with respect to the outside air temperature. Also, although the conditions for performing only motor heating or using crankcase heater heating in combination are set, the output may be adjusted by changing the ratio of motor heating and crankcase heater heating more finely.

[0077] In step S211, if the condition for using both motor heating and crankcase heater heating is satisfied (combined use), the control proceeds to step S212. In step S212, the outdoor unit control device 26 uses both the heat generation by applying current to the compressor motor 21a and the heat generation by energizing the crankcase heater 32 to start rapid preheating and proceeds with the control to step S214.

[0078] On the one hand, in step S211, when the condition for using motor heating alone (alone) is satisfied, the control proceeds to step S213. In step S213, the outdoor unit control device 26 starts rapid preheating solely by generating heat by applying current to the compressor motor 21a, and the control proceeds to step S214.

[0079] In step S214, the outdoor unit control device 26 determines whether the compressor temperature is equal to or higher than the threshold temperature, or whether the threshold time has elapsed since the start of rapid preheating. If in step S214, the compressor temperature is lower than the threshold temperature and the threshold time has not elapsed since the start of rapid preheating (NO), step S214 is looped and waiting for the condition to be satisfied. On the other hand, if in step S214, the compressor temperature is equal to or higher than the threshold temperature (YES) or the threshold time has elapsed since the start of rapid preheating (YES), the control proceeds to step S215.

[0080] In step S215, the outdoor unit control device 26 stops rapid preheating, proceeds to step S216, and shifts to the normal operation in which the compressor 21 operates. In step S215, the outdoor unit control device 26 stops normal preheating according to the mode of rapid preheating. For example, when heating is performed by the heat generation of the compressor 21, the outdoor unit control device 26 stops applying current to the compressor motor 21a. When heating is performed by the crankcase heater 32, the outdoor unit control device 26 stops energizing the crankcase heater 32.

[0081] According to the above configuration, in addition to the advantages of the embodiments described with reference to FIGS. 1 to 4 above, by designating or simultaneously executing either crankcase heater heating or motor heating according to the detected value of the temperature sensor, there is an advantage that rapid preheating is possible by adjusting the output.

[0082] Hereinafter, with reference to FIG. 7, the effect of achieving both power consumption reduction and user convenience in the air conditioning system 1 according to an embodiment of the present invention will be described. FIG. 7(A) shows a preheating operation in which operation is performed as scheduled when an operation schedule time is set. FIG. 7(B) shows a preheating operation when there is an operation command outside the schedule when the operation schedule time is set.

[0083] As shown in FIG. 7(A), when operation is performed as scheduled, normal preheating is started from the normal preheating start scheduled time obtained by subtracting the required time for compressor heating from the operation schedule time so as to be in time for the operation schedule time. Thereby, compared with the case of executing control to always maintain a predetermined compressor temperature, power consumption reduction due to preheating during most of the standby time is expected. On the other hand, as shown in FIG. 7(B), when there is an operation command from the user outside the schedule, in response to the operation command from the user, the compressor 21 is heated with an output larger than that of normal preheating, and a predetermined compressor temperature is reached in a shorter time compared with normal preheating. Thereby, operation can be started promptly in response to the operation command. And, whether the operation is performed as scheduled or outside the schedule, the frequency of compressor heating during the period when the compressor 21 is stopped can be suppressed to only once immediately before the start of operation. Thereby, without restrictions on the number of compressors, it is possible to achieve both prompt start of operation in response to an operation command outside the schedule and reduction of standby power compared with the case of executing control to always maintain a predetermined compressor temperature.

[0084] In the description of the above-described embodiment, the normal preheating has been described as being performed according to the operation schedule. However, the mode of normal preheating is not limited to the above-described one. In one or more other embodiments, the outdoor unit control device 26 may control to execute the above-described normal preheating at a frequency according to the detected values of one or more temperature sensors, more specifically, the detected values of the compressor temperature sensor 31 and the outside air temperature sensor 33, or periodically, or irregularly. Even in this case, by reducing the frequency of normal preheating as compared with the normal case and performing rapid heating in response to an operation command outside the schedule, it is possible to achieve both the start of rapid operation in response to an operation command outside the schedule without any restriction on the number of compressors and the reduction of standby power as compared with the case of executing control to always maintain a predetermined compressor temperature.

[0085] As described above, according to the embodiment of the present invention, it is possible to provide an air conditioning system and a control method for an air conditioning system that can achieve both the reduction of standby power as compared with the case of starting rapid operation in response to an operation command outside the schedule without any restriction on the number of compressors and executing control to always maintain a predetermined compressor temperature.

[0086] In the above description, the multi-air conditioning system for buildings has been described as an example. However, the air conditioning system to which the air conditioning system of the present disclosure is applicable is not particularly limited, and it is applicable to various air conditioning systems such as room air conditioners, package air conditioners, and multi-air conditioners for buildings.

[0087] The embodiment of the present invention is not limited to the above-described embodiment, and various modifications may be included. For example, the above-described embodiment has been described in detail for easy understanding, and is not necessarily limited to the one having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations is possible.

Description of Symbols

[0088] 1…Air conditioning system, 2…Pipe, 10…Indoor unit, 11…Indoor heat exchanger, 12…Indoor fan, 13…Room temperature sensor, 14…Indoor expansion valve, 20…Outdoor unit, 21…Compressor, 21a…Compressor motor, 22…Outdoor heat exchanger, 23…Outdoor fan, 24…Outdoor expansion valve, 25…Four-way valve, 26…Control device, 30…Inverter, 31…Compressor temperature sensor, 32…Crankcase heater, 33…Outside air temperature sensor, 40…Operating device, 50…Remote controller

Claims

1. In an air conditioning system in which an outdoor unit, an indoor unit, and an operating device having a management function are connected, the outdoor unit includes a compressor having a compressor motor, an inverter that applies current to the compressor motor, one or more temperature sensors, and a control device that controls normal preheating of the compressor, the control device responds to an operation command via the operating device, and based on the detected values of the one or more temperature sensors, applies a current for heat generation to the compressor motor via the inverter so as to obtain a heating amount greater than the normal preheating, thereby performing rapid preheating of the compressor and executing control to shift to an operation in which the compressor operates. An air conditioning system.

2. The outdoor unit includes a crankcase heater, and the control device adjusts the output by combining heating of the compressor by energizing the crankcase heater and heating of the compressor by applying the current to the compressor motor via the inverter based on the detected values of the one or more temperature sensors, and executes the rapid preheating. The air conditioning system according to claim 1, characterized in that.

3. The outdoor unit includes a blower, the control device controls to drive the blower to generate convection and cool the inverter during the rapid preheating in a state where the compressor is stopped. The air conditioning system according to claim 1.

4. When an operation schedule time is set, the control device calculates the required time for compressor heating based on the detected values of the one or more temperature sensors, starts heating of the compressor at a time corresponding to the operation schedule time and the required time for compressor heating, and controls to execute the normal preheating by the operation schedule time. The air conditioning system according to claim 1.

5. The normal preheating uses heat generation by applying current to the compressor motor, heat generation by energizing the crankcase heater, or both. The air conditioning system according to claim 4.

6. The rapid preheating is performed so that the compressor temperature reaches a predetermined threshold temperature within a shorter time than the normal preheating in a stopped state of the compressor. The air conditioning system according to claim 1.

7. The one or more temperature sensors are an outside air temperature sensor that measures the outside air temperature, and a compressor temperature sensor that measures the temperature of the compressor The air conditioning system according to claim 1, comprising

8. A control method for an air conditioning system in which an outdoor unit, an indoor unit, and an operating device having a management function are connected, wherein the outdoor unit includes a compressor having a compressor motor, an inverter that applies current to the compressor motor, one or more temperature sensors, and a control device that controls normal preheating of the compressor, and the control device detects an operation command via the operation device; in response to detecting the operation command, a step of performing rapid preheating of the compressor by applying a current for heat generation to the compressor motor via the inverter so as to obtain a heating amount greater than the normal preheating based on the detection values of the one or more temperature sensors; and a step of shifting to an operation in which the compressor operates The control method to execute.

9. The outdoor unit includes a crankcase heater, and the control device when performing the rapid preheating, based on the detection values of the one or more temperature sensors, a step of adjusting the output by combining heating of the compressor by energizing the crankcase heater and heating of the compressor by applying the current to the compressor motor via the inverter; The control method according to claim 8, further comprising.

10. The outdoor unit includes a blower, and the control device when performing the rapid preheating in a state where the compressor is stopped, a step of generating convection by driving the blower to cool the inverter The control method according to claim 8, further comprising.

11. The control device when an operation schedule time is set, calculates a required compressor heating time based on the detection values of the one or more temperature sensors; and a step of starting heating of the compressor so as to perform the normal preheating until the operation schedule time in response to the arrival of a time corresponding to the set operation schedule time and the calculated required compressor heating time. The control method according to claim 8, further comprising.

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