JP2022149719A - air conditioner - Google Patents

Abstract

To provide an air conditioner which prevents excessive room temperature rise by changing the temperature to increase the room temperature before a defrosting operation according to a frosting condition of an outdoor heat exchanger, and which can suppress wasteful power consumption.SOLUTION: An air conditioner 1 includes: a refrigerant circuit 5 which includes a compressor 10, an indoor heat exchanger 15, and an outdoor heat exchanger 12, and in which a refrigerant circulates; a four-way valve 11 which switches the direction of the circulating refrigerant; and an outdoor unit control part 21 which switches, by the switching of the four-way valve 11, between a heating operation for performing a heating operation so that an indoor temperature reaches a set temperature and a defrosting operation for performing defrosting of the heat exchanger 12 which is frosted by the heating operation. When switching the heating operation to the defrosting operation, the outdoor unit control part 21 sets a target temperature in which the temperature according to the frosted state of the outdoor heat exchanger 12 is added to the set temperature, and after the heating operation is performed so that the indoor temperature reaches the target temperature, it performs the defrosting operation.SELECTED DRAWING: Figure 3

Description

The present invention relates to an air conditioner, and relates to defrosting control in heating operation.

Patent Document 1 includes a compressor, an indoor heat exchanger, an outdoor heat exchanger, a refrigeration cycle having an expansion device, and a control unit that controls the compressor so that the room temperature of the room to be conditioned reaches the set temperature, There is disclosed an air conditioner that shifts a set temperature in a positive direction to a predetermined temperature when a defrosting operation start condition is satisfied during heating operation, and starts defrosting operation after a predetermined time has elapsed.
Normally, in defrosting operation, the four-way valve is switched to switch the refrigerant circuit to a cooling cycle, and hot gas is sent to the outdoor heat exchanger to melt frost adhered to the outdoor heat exchanger. Therefore, an indoor unit having an indoor heat exchanger is operated with zero heating capacity, which poses a problem that the user feels cold during the defrosting operation.
In order to solve the problem, in Patent Document 1, immediately before switching from the heating operation to the defrosting operation, the set temperature is shifted in the positive direction to warm the room in advance so that the user feels cold. It prevents the room temperature from dropping.

JP 2009-109099 A

However, in Patent Document 1, the set temperature is shifted in the positive direction of the predetermined temperature immediately before the defrosting operation to warm the room in advance, and then the defrosting operation is started. Since a constant temperature is added to the set temperature regardless of the state, if the defrosting time is short and the heating capacity does not decrease much, or if the outside temperature is high and the room temperature does not decrease much, the set temperature will not be raised excessively. There is a problem that power consumption increases and the room temperature becomes higher than the room temperature desired by the user, which makes the user feel uncomfortable.
In view of the above problems, an object of the present invention is to prevent an excessive rise in room temperature by determining a set temperature for raising room temperature before defrosting operation according to the frosting state of the outdoor heat exchanger, and to prevent wasteful To provide an air conditioner capable of suppressing unnecessary power consumption.

One aspect of the present invention includes a refrigerant circuit having a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger and in which refrigerant circulates; Heating operation for heating so that the air temperature in the room where the path switching valve and the indoor heat exchanger are installed reaches the set temperature, and defrosting operation for defrosting the outdoor heat exchanger frosted by the heating operation In an air conditioner having a control unit that switches by switching a flow path switching valve, the control unit adjusts the temperature according to the frosting state of the outdoor heat exchanger to the set temperature when switching the heating operation to the defrosting operation. The air conditioner performs defrosting operation after setting the added target temperature and performing heating operation so that the room temperature reaches the target temperature.

According to the present invention, by raising the room temperature before the defrosting operation according to the frosting state of the outdoor heat exchanger, an excessive rise in the room temperature can be prevented and wasteful power consumption can be suppressed. provide the machine.

1 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention; FIG. 1 is a configuration diagram of a control block of an air conditioner according to an embodiment of the present invention; FIG. It is a control flow chart of the air conditioner concerning the embodiment of the present invention.

EMBODIMENT OF THE INVENTION Below, embodiment of the air conditioner which concerns on this invention is described in detail based on drawing. In addition, this invention is not limited by this embodiment.

FIG. 1 is a refrigerant circuit diagram of an air conditioner 1 of this embodiment. FIG. 2 is a configuration diagram of the control block of the air conditioner 1 of this embodiment. FIG. 3 is a control flow chart of the air conditioner of this embodiment.

An air conditioner 1 will be described with reference to FIG. FIG. 1 shows a refrigerant circuit diagram of an air conditioner 1 according to an embodiment of the present invention. An air conditioner 1 is capable of cooling operation and heating operation, and includes an outdoor unit 2 arranged outdoors and an indoor unit 3 arranged indoors. The outdoor unit 2 includes a compressor 10, a four-way valve 11, an outdoor heat exchanger 12, and an outdoor unit side expansion valve 13 connected by refrigerant pipes 4. Compressor 10 , four-way valve 11 , outdoor heat exchanger 12 , outdoor unit side expansion valve 13 , indoor unit side expansion valve 15 , indoor heat exchanger 16 , refrigerant circuit 5 constitutes The outdoor unit 2 also includes an air blower (not shown) for taking in outside air, sending it to the outdoor heat exchanger 12, exchanging heat with the refrigerant in the outdoor heat exchanger 12, and sending the air out. The indoor unit 3 also includes an indoor fan (not shown) for taking indoor air, sending it to the indoor heat exchanger 16, exchanging heat with the refrigerant in the indoor heat exchanger 13, and sending the air. The four-way valve 11 is a channel switching valve that changes the direction of flow of the refrigerant circulating in the refrigerant circuit 5 during cooling operation and during heating operation. During cooling operation, the refrigerant discharged from the compressor 10 passes through the four-way valve 11 to the outdoor heat exchanger 12, the outdoor unit side expansion valve 13, the indoor unit side expansion valve 15, the indoor heat exchanger 16, the four-way valve 11, the compression During heating operation, the refrigerant discharged from the compressor 10 passes through the four-way valve 11 to the indoor heat exchanger 16, the indoor unit side expansion valve 15, the outdoor unit side expansion valve 13, and the outdoor heat exchanger 12. , the four-way valve 11 and the compressor 10 .

The flow of refrigerant in the refrigerant circuit 5 during heating operation will be described. In FIG. 1, solid arrows indicate the flow of the refrigerant during the heating operation. The heating operation is an air conditioning operation in which heating is performed based on the set temperature (the initially set temperature, eg, 24° C.) transmitted from the indoor unit 3 so as to reach the set temperature. During heating operation, the high-temperature and high-pressure refrigerant compressed by the compressor 10 flows through the indoor heat exchanger 16 via the four-way valve 11 . The high-temperature, high-pressure refrigerant flowing through the indoor heat exchanger 16 exchanges heat with indoor air blown by an indoor fan to radiate heat, and the indoor air that has exchanged heat with the high-temperature, high-pressure refrigerant is warmed. After passing through the indoor heat exchanger 16 and radiating heat, the refrigerant passes through the indoor unit side expansion valve 15 and is decompressed by the outdoor unit side expansion valve 13 to become low temperature and low pressure. The low-temperature and low-pressure refrigerant flows through the outdoor heat exchanger 12, and when passing through the outdoor heat exchanger 12, it exchanges heat with the outside air blown by the blower and absorbs heat. The refrigerant that has absorbed heat returns to the compressor 10 via the four-way valve 11 and is again compressed to a high temperature and high pressure. It should be noted that the flow of the refrigerant during the cooling operation is the opposite of that during the heating operation, and there is no difference from the conventional technology, so the description is omitted in this specification.

Next, the flow of refrigerant in the refrigerant circuit 5 during defrosting operation will be described. In FIG. 1, the dashed arrow indicates the flow of the refrigerant during the defrosting operation. The refrigerant flow in the refrigerant circuit 5 during the defrosting operation is the same as that during the cooling operation. Note that the control when switching from the heating operation to the defrosting operation will be described later. Switching from the heating operation to the defrosting operation is performed by switching the direction of the flow of the refrigerant circulating in the refrigerant circuit 5 by the four-way valve 11 to the opposite direction. In the heating operation, a high-temperature, high-pressure refrigerant flows through the indoor heat exchanger 16 , and a low-temperature, low-pressure refrigerant flows through the outdoor heat exchanger 12 . Therefore, when the outside air temperature is relatively low (for example, 2°C to 5°C or below), the temperature of the outdoor heat exchanger 12 becomes 0°C or below, and the moisture contained in the outside air turns into frost and adheres to the outdoor heat exchanger 12 ( frost formation). If the heating operation continues after that, the frost will grow gradually, and eventually the heat exchange capacity of the outdoor heat exchanger 12 will decrease due to the frost, and the heating capacity will drop. Perform defrosting operation.

During the defrosting operation, the high-temperature and high-pressure refrigerant compressed by the compressor 10 flows through the outdoor heat exchanger 12 via the four-way valve 11 . The frosted outdoor heat exchanger 12 , that is, the frosted outdoor heat exchanger 12 is defrosted by passing the high-temperature, high-pressure refrigerant through the outdoor heat exchanger 12 to melt the frost. After passing through the outdoor heat exchanger 12 , the refrigerant flows through the outdoor unit side expansion valve 13 , the indoor unit side expansion valve 15 and the indoor heat exchanger 16 . The refrigerant that has passed through the indoor heat exchanger 16 returns to the compressor 10 via the four-way valve 11 and is again compressed to a high temperature and high pressure. Therefore, in the defrosting operation, the high-temperature and high-pressure refrigerant compressed by the compressor 10 flows through the outdoor heat exchanger 12 instead of the indoor heat exchanger 16, and the low-temperature and low-pressure refrigerant flows through the indoor heat exchanger 16. Become.

Next, a configuration diagram of a control block of the air conditioner 1 according to the embodiment will be described with reference to FIG. The outdoor unit 2 of the air conditioner 1 includes an outdoor unit control unit 21 as a control unit that controls cooling operation, heating operation, and defrosting operation. The outdoor unit 2 includes an outdoor unit control unit 21, a drive circuit 22 for controlling the compressor 10, a communication unit 23 for communicating with the indoor unit 3, a timer 24 for measuring the operating time of the compressor 10, and an outdoor unit control unit 21. An outdoor heat exchanger temperature sensor 25 for detecting the temperature of the heat exchanger 12 and an outdoor air temperature sensor 26 for detecting the outside air temperature are provided. The outdoor unit control unit 21 operates the compressor 10, the four-way valve 11, and the outdoor unit side expansion valve 13 according to the operation mode such as cooling operation and heating operation transmitted from the indoor unit 3, and the set temperature set in the indoor unit 3. , controls the indoor unit side expansion valve 15, and also detects the temperature of the outdoor heat exchanger 12 sent from the outdoor heat exchanger temperature sensor 25, the outside air temperature sent from the outside air temperature sensor 26, and the temperature sent from the timer 24. Defrosting operation is controlled when it is determined whether or not the frost formation condition is satisfied according to the operating time of the compressor 10 .

Next, determination of the frost formation state will be described. The outdoor unit control unit 21 determines whether frost formation is normal frost formation or integrated frost formation. Normal frost formation is a state in which frost forms in a short period of time, and is a state in which the amount of frost formed is determined to be large. A state in which the amount of frost is determined to be less than normal frost.

Normal frost formation is judged to be normal frost formation when the following conditions are satisfied.
A: When the continuous operation time of the compressor 10 is 10 minutes or more and either the following condition 1 or condition 2 is satisfied Condition 1:
(1) The cumulative operating time of the compressor 10 is 17 minutes or longer.
(2) The temperature of the outdoor heat exchanger 12 is -9°C or lower.
(3) The temperature difference between the outdoor air temperature and the outdoor heat exchanger 12 is 5°C or more, and the temperature difference between the outdoor air temperature and the outdoor heat exchanger 12 is still 5 minutes after detecting the temperature difference of 5°C or more. 5°C or higher.
Condition 2:
(1) The cumulative operating time of the compressor 10 is 17 minutes or longer.
(2) The temperature of the outdoor heat exchanger 12 is -5°C or lower, and the temperature of the outdoor heat exchanger 12 is -5°C even after 5 minutes from detecting the temperature of -5°C or lower. °C or less.

Accumulated frost formation is determined to be accumulated frost formation when the following conditions are satisfied.
B: When the continuous operation time of the compressor 10 is 10 minutes or more and the following condition 3 is satisfied Condition 3:
(1) The cumulative operating time of the compressor 10 is 210 minutes or longer.
(2) The temperature of the outdoor heat exchanger 12 is -3°C or lower, and the temperature of the outdoor heat exchanger 12 is -3°C even 30 minutes after the temperature of the outdoor heat exchanger 12 is detected to be -3°C or lower. °C or less.

Next, the control of the defrosting operation will be described using the control flow diagram of FIG. 3 . It is determined whether or not the above-described frosting condition is satisfied during heating operation (S1). Next, it is determined whether or not the frost formation condition satisfies the normal frost formation condition (S2). If the condition is satisfied (YES in S2), it is determined whether or not the outside air temperature is equal to or higher than a predetermined temperature (eg, 10° C.) (S3). If the outside air temperature is 10°C or higher, the process proceeds to S6, and the target temperature in the heating operation ( 25.5°C). If the outside air temperature is less than 10°C, the process proceeds to S5, and the target temperature (26°C ). If the conditions for normal frost formation are not satisfied in S2 (NO in S2), it is determined whether the outside air temperature is equal to or higher than a predetermined temperature (eg, 10° C.) (S4). If the outside air temperature is 10°C or higher, the process proceeds to S7, and the initially set temperature (24°C) plus a low temperature (for example, 1°C) is set to the target temperature (25°C) in the heating operation. ) (S7). If the outside air temperature is less than 10°C, the process proceeds to S6, and the target temperature in the heating operation ( 25.5° C.) (S6).

Next, the heating operation is performed until the indoor temperature of the indoor unit 3 reaches the changed target temperature (for example, 25°C, 25.5°C, 26°C) from the initially set temperature (24°C) (S8 ), and when the indoor temperature reaches the target temperature due to the heating operation (YES in S8), the heating operation is switched to the defrosting operation (S9). In this embodiment, the defrosting operation is switched to after reaching the target temperature. It does not matter if the operation is switched to the defrosting operation. When the conditions for ending the defrosting operation are reached, the defrosting operation is ended (YES in S10). When the defrosting operation ends, the target temperature is returned to the initially set temperature (24° C.), and the heating operation is started (S11). The conditions for ending the defrosting operation are shown below.
Termination condition of defrost operation: When the following (1) or (2) is established.
(1) The temperature of the outdoor heat exchanger 12 is equal to or higher than a predetermined temperature (for example, 16°C).
(2) A predetermined time (for example, 15 minutes) has passed since the defrosting operation started.

A feature of the air conditioner 1 of the present embodiment is that the set temperature for the heating operation is changed according to the amount of frost formation (that is, the state of frost formation determined by the frost formation conditions) and the outside air temperature. That is, if the amount of frost formed is large, the defrosting operation time is long, and if the outside temperature is low, the outside temperature has a large effect on the decrease in the indoor temperature. Therefore, the heating operation is performed at a target temperature that is much higher than the initially set temperature to raise the indoor temperature (S5), and then the defrosting operation is performed. If the amount of frost formed is small, the defrosting operation time is short, and if the outside temperature is high and the outside temperature does not have a large effect on the decrease in the indoor temperature, the heating capacity will decrease due to the defrosting operation and the room temperature will increase due to the defrosting operation. Since the decrease is small, the heating operation is performed at the target temperature slightly higher than the initially set temperature to raise the indoor temperature (S7), and then the defrosting operation is performed. In the intermediate case, the heating operation is performed at a target temperature that is moderately higher than the initially set temperature to raise the indoor temperature (S6), and then the defrosting operation is performed. By determining a target temperature higher than the set temperature before the defrosting operation according to the frosting state of the outdoor heat exchanger 12 and the outside air temperature, an excessive rise in room temperature is prevented and wasteful power consumption is suppressed. can be done.

In the present embodiment, the set temperature for the heating operation is changed according to the frost amount (frost state) and the outside air temperature, but only one of them may be used. For example, only the amount of frost formation (state of frost formation) may be determined, and the set temperature for the heating operation may be changed according to the amount of frost formation (state of frost formation). Alternatively, only the outside air temperature may be determined, and the set temperature for the heating operation may be changed according to the outside air temperature.

Further, in the present embodiment, the set temperature for the heating operation is changed according to the frost amount (frost state) and the outside air temperature. You can change the temperature. The defrosting operation time can be predicted based on the above-described frosting conditions and outside air temperature. That is, it is predicted that the defrosting operation time will be long when the frosting condition satisfies the normal frosting condition in which the amount of frost is determined to be large and the outside air temperature is low. Further, when the frost formation condition satisfies the integrated frost formation condition under which the amount of frost formation is determined to be less than the normal frost formation, and the outside air temperature is high, it is predicted that the defrosting operation time will be shortened. When the frost formation condition satisfies the normal frost formation condition in which the amount of frost is judged to be large and the outside temperature is high, or the cumulative frost formation condition in which the amount of frost is judged to be smaller than the normal frost. is satisfied and the outside air temperature is low, it is predicted that the defrosting operation time is in the middle of the above time. For example, the relationship between frost formation conditions, outside air temperature, and defrosting operation time is stored in a memory (not shown), the defrosting operation time is predicted from the frost formation conditions and outside temperature, and during the predicted defrosting operation The corresponding temperature may be added to the set temperature during the heating operation and set as the target temperature.

Although the foregoing has been described with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of the embodiments based on the above disclosure will be obvious to those skilled in the art.

DESCRIPTION OF SYMBOLS 1... Air conditioner, 2... Outdoor unit, 3... Indoor unit, 4... Refrigerant piping, 5... Refrigerant circuit, 10... Compressor, 11... Four-way valve, 12... Outdoor heat exchanger, 13... Outdoor unit side expansion valve , 15... Indoor unit side expansion valve, 16... Indoor heat exchanger, 21... Outdoor unit control unit, 22... Drive circuit, 23... Communication unit, 24... Timer, 25... Outdoor heat exchanger temperature sensor, 26... Outdoor air temperature sensor

Claims (6)

a refrigerant circuit having a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger, in which the refrigerant circulates;
a flow path switching valve connected to the refrigerant circuit for switching the direction of the refrigerant circulating in the refrigerant circuit;
A heating operation in which heating is performed so that the air temperature in the room where the indoor heat exchanger is installed reaches a set temperature, and a defrosting operation in which the outdoor heat exchanger frosted by the heating operation is performed. In an air conditioner having a control unit that switches by switching a path switching valve,
When switching the heating operation to the defrosting operation, the control unit sets a target temperature obtained by adding a temperature corresponding to a frosted state of the outdoor heat exchanger to the set temperature,
An air conditioner, wherein the defrosting operation is performed after the heating operation is performed so that the air temperature in the room reaches the target temperature. Equipped with an outside temperature detection sensor that detects the outside temperature,
The control unit is characterized in that, when switching the heating operation to the defrosting operation, a target temperature is set by adding a temperature corresponding to the frost formation state of the outdoor heat exchanger and the outside air temperature to the set temperature. The air conditioner according to claim 1, wherein 3. The air conditioner according to claim 1, wherein after the defrosting operation ends, the target temperature is changed to the set temperature and the heating operation is started. a refrigerant circuit having a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger, in which the refrigerant circulates;
a flow path switching valve connected to the refrigerant circuit for switching the direction of the refrigerant circulating in the refrigerant circuit;
A heating operation in which heating is performed so that the air temperature in the room where the indoor heat exchanger is installed reaches a set temperature, and a defrosting operation in which the outdoor heat exchanger frosted by the heating operation is performed. In an air conditioner having a control unit that switches by switching a path switching valve,
When the heating operation is switched to the defrosting operation, the control unit predicts a defrosting operation time, which is an operation time of the defrosting operation, and sets a temperature corresponding to the predicted defrosting operation time to the set temperature. Set the target temperature added to
An air conditioner, wherein the defrosting operation is performed after the heating operation is performed so that the air temperature in the room reaches the target temperature. Equipped with an outside temperature detection sensor that detects the outside temperature,
5. The air conditioner according to claim 4, wherein the defrosting operation time is predicted based on the frost formation state of the outdoor heat exchanger and the outside air temperature. 6. The air conditioner according to claim 4, wherein after the defrosting operation ends, the target temperature is changed to the set temperature and the heating operation is started.

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