air conditioner

Abstract

To provide an air conditioner capable of lowering a humidity while keeping an indoor temperature at a set temperature even when the indoor temperature reaches the set temperature in a cooling operation.SOLUTION: An air conditioner includes: a refrigeration cycle device including an indoor unit main body having an air passage for communicating a suction port and a blowout port, an indoor fan for blowing out the air sucked from the suction port through the air passage from the blowout port, a compressor, and an indoor heat exchanger positioned on the air passage; and a control portion performing a cooling operation by controlling the indoor fan and the refrigeration cycle device. The control portion decreases a rotational frequency of the indoor fan without increasing a rotational frequency of the compressor in a case when the indoor temperature is lower than the set temperature and the indoor humidity is higher than a target humidity in the cooling operation.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an air conditioner.

Background Art

[0002] For example, in Patent Document 1, when the cooling load is equal to or greater than a predetermined set value, a cooling operation is performed. When the cooling load is smaller than the predetermined set value and the humidity of the indoor air detected by a humidity sensor is smaller than a predetermined threshold value, a cooling operation is performed. On the other hand, when the cooling load is smaller than the predetermined set value and the humidity of the indoor air detected by the humidity sensor is equal to or greater than the predetermined threshold value, a dehumidifying operation is performed. An air conditioner is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the air conditioner as described above, when the indoor temperature reaches the set temperature and the humidity is high, the humidity is reduced by switching to the dehumidifying operation. However, in the dehumidifying operation, since the operating frequency of the compressor is changed according to the dehumidifying load, the indoor temperature may deviate from the set temperature.

[0005] Therefore, an aspect of the present invention aims to provide an air conditioner that can reduce humidity while maintaining the indoor temperature at the set temperature during a cooling operation, for example.

Means for Solving the Problems

[0006] An air conditioner according to an aspect of the present invention includes an indoor unit main body having an air passage communicating a suction port and a blowout port, an indoor fan that blows out the air sucked from the suction port through the air passage from the blowout port, a compressor, and an indoor heat exchanger located in the air passage, and includes a refrigeration cycle device, and a control unit that controls the indoor fan and the refrigeration cycle device to perform a cooling operation. In the cooling operation, when the indoor temperature is lower than the set temperature and the indoor humidity is higher than the target humidity, the control unit decreases the rotation speed of the indoor fan without increasing the rotation speed of the compressor.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0008] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted. In addition, elements not directly related to the present invention may be omitted from the illustration. Furthermore, the forms of the constituent elements shown in such embodiments are merely examples, and the present invention is not limited to these forms.

[0009] Hereinafter, with reference to FIG. 1, an air conditioner 100 according to one aspect of the present invention will be described. The air conditioner 100 is a device for conditioning the air in a room such as a building. FIG. 1 is a schematic configuration diagram showing the air conditioner 100.

[0010] The air conditioner 100 includes an outdoor unit 110 and an indoor unit 120. The outdoor unit 110 has a compressor 111, a four-way valve 112, an expansion valve 113, an outdoor heat exchanger 114, and an outdoor fan 115. The indoor unit 120 has an indoor heat exchanger 121 and an indoor fan 122.

[0011] The air conditioner 100 includes a refrigeration cycle device. The refrigeration cycle device is configured by sequentially connecting a compressor 111, a four-way valve 112, an outdoor heat exchanger 114, an expansion valve 113, and an indoor heat exchanger 121 with pipes.

[0012] The compressor 111 is a mechanism that compresses low-pressure refrigerant to high pressure in the refrigeration cycle device. The compressor 111 is, for example, a compressor that is rotationally driven by a motor. The motor of the compressor 111 can be controlled in terms of the rotation speed (frequency) by an inverter or the like.

[0013] The four-way valve 112 is a valve that switches the direction of refrigerant circulation according to cooling operation or heating operation in the refrigeration cycle device. During cooling operation, the four-way valve 112 connects the discharge side of the compressor 111 to the outdoor heat exchanger 114 and connects the suction side of the compressor 111 to the indoor heat exchanger 121. During heating operation, the four-way valve 112 connects the discharge side of the compressor 111 to the indoor heat exchanger 121 and connects the suction side of the compressor 111 to the outdoor heat exchanger 114.

[0014] The expansion valve 113 expands and depressurizes the refrigerant flowing between the outdoor heat exchanger 114 and the indoor heat exchanger 121. The expansion valve 113 is, for example, an electric expansion valve capable of opening degree control. During the cooling operation, the expansion valve 113 depressurizes the high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 114 before sending it to the indoor heat exchanger 121. Also, during the heating operation, the expansion valve 113 depressurizes the high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 121 before sending it to the outdoor heat exchanger 114.

[0015] The outdoor heat exchanger 114 performs heat exchange between the air sucked into the outdoor unit 110 by the outdoor fan 115 and the refrigerant. The outdoor heat exchanger 114 functions as an evaporator during the cooling operation and as a condenser during the heating operation.

[0016] The indoor heat exchanger 121 performs heat exchange between the air sucked into the indoor unit 120 by the indoor fan 122 and the refrigerant. The indoor heat exchanger 121 functions as a condenser during the cooling operation and as an evaporator during the heating operation.

[0017] The indoor unit 120 will be specifically described with reference to FIGS. 2 and 3. FIG. 2 is a front view showing the indoor unit 120. FIG. 3 is a side cross-sectional view showing the indoor unit 120. FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2. In the following description, in the indoor unit 120, the side of the indoor wall surface to which the indoor unit 120 is attached is defined as the rear side, the opposite side is defined as the front side, the side where the suction port 123 of the indoor unit 120 is provided is defined as the upper side, and the opposite side is defined as the lower side for explanation. However, these directions are directions defined for convenience in the explanation and are not intended to define the directions during use.

[0018] The indoor unit 120 includes an indoor unit main body 120a that houses various structures. The upper surface of the indoor unit main body 120a is formed with a suction port 123. The lower surface of the indoor unit main body 120a is formed with a blowout port 124. The blowout port 124 is provided with a louver 124a for changing the direction of the blown air. The louver 124a is configured to be tiltable with respect to the blowout port 124. An air passage 120b that communicates the suction port 123 and the blowout port 124 is formed in the indoor unit main body 120a. An indoor heat exchanger 121 and an indoor fan 122 are arranged in the air passage 120b. The indoor heat exchanger 121 is arranged so as to surround the upper part of the indoor fan 122.

[0019] In the above configuration, the indoor unit 120 rotates the indoor fan 122, so that the air sucked from the suction port 123 exchanges heat with the refrigerant flowing through the indoor heat exchanger 121. Then, the heat-exchanged air is blown out from the blowout port 124, whereby the air in the space where the indoor unit 120 is arranged can be conditioned.

[0020] With reference to FIG. 4, the hardware configuration of the air conditioner 100 will be described. FIG. 4 is a block diagram showing the hardware configuration of the air conditioner 100.

[0021] The air conditioner 100 includes a control unit 200, a storage unit 210, a communication unit 220, a remote control 230, a compressor 111, a four-way valve 112, an expansion valve 113, an indoor fan 122, an outdoor fan 115, a first temperature sensor 130, a second temperature sensor 131, a third temperature sensor 132, a fourth temperature sensor 133, a fifth temperature sensor 134, a sixth temperature sensor 135, a seventh temperature sensor 136, a humidity sensor 137, and the like.

[0022] The control unit 200 is composed of, for example, a CPU (Central Processing Unit). The control unit 200 controls the air conditioner 100 by reading and executing the programs and data recorded in the storage unit 210.

[0023] The memory unit 210 is, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and records programs executed by the control unit 200, various parameters used by the control unit 200, and the like.

[0024] The communication unit 220 controls, for example, wireless communication of various data with a remote control. The communication unit 220 is not limited to wireless communication with a remote control, and may control wireless communication with an external terminal such as a server device or a smartphone, for example.

[0025] The remote control 230 is an operating device for starting and stopping operations in various operation modes, switching operation modes, and the like. Further, the remote control 230 can set the set temperature of the indoor temperature, the air volume, and the air direction. Instructions input to the remote control 230 are sent to the control unit 200, and various operation modes and the like are executed.

[0026] The first temperature sensor 130 detects the discharge temperature of the compressor 111. The second temperature sensor 131 detects the suction temperature of the compressor 111. The third temperature sensor 132 detects the refrigerant temperature in the outdoor heat exchanger 114. The fourth temperature sensor 133 detects the intake temperature of the outdoor heat exchanger 114 as the outside air temperature. The fifth temperature sensor 134 detects the refrigerant temperature between the expansion valve 113 and the indoor heat exchanger 121 in the outdoor unit 110. The sixth temperature sensor 135 detects the intake temperature of the indoor heat exchanger 121 as the indoor temperature. The seventh temperature sensor 136 detects the refrigerant temperature in the indoor heat exchanger 121. The humidity sensor 137 detects the intake humidity of the indoor heat exchanger 121 as the indoor humidity.

[0027] Hereinafter, various operations by the control unit 200 will be described.

[0028] During the heating operation, the control unit 200 controls the four-way valve 112 so that the indoor heat exchanger 121 functions as an evaporator and the outdoor heat exchanger 114 functions as a condenser. As a result, the refrigerant is sucked into the compressor 111, compressed to a high pressure, and then discharged. The high-pressure refrigerant discharged from the compressor 111 is sent to the indoor heat exchanger 121 via the four-way valve 112. The high-pressure refrigerant sent to the indoor heat exchanger 121 exchanges heat with the air supplied by the indoor fan 122 in the indoor heat exchanger 121 and dissipates heat. Thereby, the indoor air is heated and blown into the room from the air outlet 124. The high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 121 is sent to the expansion valve 113 and decompressed to a low pressure. The low-pressure refrigerant decompressed in the expansion valve 113 is sent to the outdoor heat exchanger 114. The low-pressure refrigerant sent to the outdoor heat exchanger 114 exchanges heat with the air supplied by the outdoor fan 115 in the outdoor heat exchanger 114 and evaporates. The low-pressure refrigerant that has evaporated in the outdoor heat exchanger 114 is sucked into the compressor 111 again through the four-way valve 112.

[0029] For example, during the heating operation, the control unit 200 controls the rotational speed of the motor of the compressor 111 (hereinafter also referred to as the rotational speed of the compressor 111) based on the air conditioning load. Specifically, the rotational speed of the compressor 111 is changed based on the difference between the detected value (indoor temperature) of the sixth temperature sensor 135 and the set temperature. When the difference between the indoor temperature and the set temperature is large, the control unit 200 controls the rotational speed of the compressor 111 to increase because the air conditioning load is large. On the other hand, when the difference between the indoor temperature and the set temperature is small, the control unit 200 controls the rotational speed of the compressor 111 to decrease because the air conditioning load is small.

[0030] In the heating operation, when the indoor temperature becomes equal to or higher than the set temperature, the control unit 200 executes a constant-speed operation of the compressor 111, or a so-called intermittent operation in which when the indoor temperature exceeds the determination temperature, the control unit repeats a thermo-off operation to stop the operation of the compressor 111 and a thermo-on operation to start the operation of the compressor 111, thereby stabilizing the indoor temperature in a temperature range near the set temperature. Regarding which operation, the constant-speed operation of the compressor 111 or the intermittent operation of the compressor 111, to execute, the power consumption in each operation may be calculated, and the operation with less power consumption may be executed. Further, when the rotational speed of the compressor 111 for stabilizing the temperature in the temperature range near the set temperature is lower than the minimum rotational speed of the compressor 111, the intermittent operation of the compressor 111 may be performed.

[0031] In the cooling operation, the control unit 200 controls the four-way valve 112 so that the indoor heat exchanger 121 functions as a condenser and the outdoor heat exchanger 114 functions as an evaporator. As a result, the refrigerant is sucked into the compressor 111, compressed to a high pressure, and then discharged. The high-pressure refrigerant discharged from the compressor 111 is sent to the outdoor heat exchanger 114 via the four-way valve 112. The high-pressure refrigerant sent to the outdoor heat exchanger 114 exchanges heat with the air supplied by the outdoor fan 115 in the outdoor heat exchanger 114 and dissipates heat. The high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 114 is sent to the expansion valve 113 and depressurized to a low pressure. The low-pressure refrigerant depressurized in the expansion valve 113 is sent to the indoor heat exchanger 121. The low-pressure refrigerant sent to the indoor heat exchanger 121 exchanges heat with the air supplied by the indoor fan 122 in the indoor heat exchanger 121 and evaporates. As a result, the indoor air is cooled and blown into the room from the air outlet 124. The low-pressure refrigerant that has evaporated in the indoor heat exchanger 121 is sucked into the compressor 111 again through the four-way valve 112.

[0032] For example, in the cooling operation, the control unit 200 controls the rotational speed of the motor of the compressor 111 based on the air conditioning load. Specifically, it changes the rotational speed of the compressor 111 based on the difference between the detected value (indoor temperature) of the sixth temperature sensor 135 and the set temperature. When the difference between the indoor temperature and the set temperature is large, since the air conditioning load is large, the control unit 200 controls the rotational speed of the compressor 111 to increase. On the other hand, when the difference between the indoor temperature and the set temperature is small, since the air conditioning load is small, the control unit 200 controls the rotational speed of the compressor 111 to decrease.

[0033] In the cooling operation, when the indoor temperature becomes equal to or lower than the set temperature, the control unit 200 performs an operation to keep the rotational speed of the compressor 111 constant, or when the indoor temperature becomes equal to or lower than the determination temperature, the control unit 200 repeats a so-called intermittent operation that stops the operation of the compressor 111 (thermo-off) and starts the operation of the compressor 111 (thermo-on) to stabilize the indoor temperature in a temperature range near the set temperature. Regarding which operation to perform, the operation of keeping the rotational speed of the compressor 111 constant or the intermittent operation of the compressor 111, the power consumption in each operation may be calculated and the operation with less power consumption may be performed. Also, when the rotational speed of the compressor 111 for stabilizing the temperature in the range near the set temperature is lower than the minimum rotational speed of the compressor 111, the intermittent operation of the compressor 111 may be performed.

[0034] In the dehumidifying operation, similar to the cooling operation, the control unit 200 controls the four-way valve 112 so that the indoor heat exchanger 121 functions as a condenser and the outdoor heat exchanger 114 functions as an evaporator. The low-pressure refrigerant sent to the indoor heat exchanger 121 evaporates by exchanging heat with the air supplied by the indoor fan 122 in the indoor heat exchanger 121. As a result, the indoor air is dehumidified and blown into the room.

[0035] For example, during the dehumidification operation, the control unit 200 controls the rotational speed of the compressor 111 based on the load related to humidity. Specifically, it changes the rotational speed of the compressor 111 based on the difference between the detected value of the humidity sensor 137 (the humidity in the room) and the target humidity. When the difference between the humidity in the room and the target humidity is large, the control unit 200 controls the rotational speed of the compressor 111 to increase because the load related to humidity is large. On the other hand, when the difference between the humidity in the room and the target humidity is small, the control unit 200 controls the rotational speed of the compressor 111 to decrease because the load related to humidity is small.

[0036] Using FIG. 4, the dehumidification process during the cooling operation by the control unit 200 will be described. During normal cooling operation, the control unit 200 controls the rotational speed of the compressor 111, the opening degree of the expansion valve 113, etc. so that the temperature in the room becomes the set temperature.

[0037] The control unit 200 includes, for example, a temperature acquisition unit 201 that acquires the temperature in the room at any time, a humidity acquisition unit 202 that acquires the humidity in the room, a first determination unit 203 that determines whether the temperature in the room is lower than the set temperature, a second determination unit 204 that determines whether the humidity in the room is higher than the target humidity, a third determination unit 205 that determines whether the rotational speed of the indoor fan 122 has reached a predetermined rotational speed, a drive control unit 206 that controls the compressor 111 and the indoor fan 122, and a dew point temperature calculation unit 207 that calculates the dew point temperature.

[0038] The temperature acquisition unit 201 acquires the temperature in the room at any time. The temperature acquisition unit 201 acquires the detected value of the sixth temperature sensor 135 as the temperature in the room. Although the temperature acquisition unit 201 acquires the detected value of the sixth temperature sensor 135, it is not limited to this. For example, it may acquire the temperature in the room from a temperature sensor arranged outside the air conditioner 100 via the communication unit 220.

[0039] The humidity acquisition unit 202 continuously acquires the indoor humidity. The humidity acquisition unit 202 acquires the detected value of the humidity sensor 137 as the indoor humidity. Although the humidity acquisition unit 202 acquires the detected value of the humidity sensor 137, it is not limited to this. For example, the indoor humidity may be acquired from a humidity sensor disposed outside the air conditioner 100 via the communication unit 220.

[0040] The first determination unit 203 compares the indoor temperature with the set temperature to determine whether the indoor temperature is lower than the set temperature. The set temperature refers to, for example, the temperature set by the user using the remote controller 230.

[0041] Also, the second determination unit 204 compares the indoor humidity with the target humidity to determine whether the indoor humidity is higher than the target humidity. The target humidity is a predetermined value. The target humidity is, for example, 55%.

[0042] Also, the third determination unit 205 determines whether the rotation speed of the indoor fan 122 has reached a predetermined rotation speed. The predetermined rotation speed is the rotation speed set with the upper limit being the rotation speed before starting to lower the indoor fan 122 described later.

[0043] When it is determined in the first determination unit 203 that the indoor temperature is lower than the set temperature and in the second determination unit 204 that the indoor humidity is higher than the target humidity, the control unit 200 starts the dehumidification process by the control unit 200.

[0044] When it is determined in the first determination unit 203 that the indoor temperature is lower than the set temperature, the drive control unit 206 controls the rotation speed of the compressor 111 to a constant rotation speed for the purpose of maintaining the indoor temperature in the temperature range near the set temperature. Here, it is maintained at a temperature lower than the set temperature.

[0045] When the first determination unit 203 determines that the indoor temperature is lower than the set temperature and the second determination unit 204 determines that the indoor humidity is higher than the target humidity, the drive control unit 206 reduces the rotation speed of the indoor fan 122. The absolute value of the change in the rotation speed per unit time when reducing the rotation speed of the indoor fan 122 is, for example, 10 rpm / 10 s.

[0046] As described above, without increasing the rotation speed of the compressor 111, by reducing the rotation speed of the indoor fan 122, the amount of air passing through the indoor heat exchanger 121 per unit time is reduced, thereby suppressing the heat exchange between the refrigerant and the indoor air and lowering the temperature of the indoor heat exchanger 121. Therefore, since the air passing through the indoor heat exchanger 121 can be cooled, the humidity can be reduced while maintaining the indoor temperature at the set temperature.

[0047] The drive control unit 206 continues to reduce the rotation speed of the indoor fan 122 until, for example, the second determination unit 204 determines that the indoor humidity has reached the target humidity.

[0048] Next, after the second determination unit 204 determines that the indoor humidity has reached the target humidity, the drive control unit 206 increases the rotation speed of the indoor fan 122.

[0049] In the present embodiment, when the second determination unit 204 determines that the indoor humidity has reached the target humidity, the drive control unit 206 maintains the rotation speed of the indoor fan 122 for a predetermined time and then increases the rotation speed of the indoor fan 122. The predetermined time is set, for example, in consideration of both stabilizing the indoor humidity distribution and suppressing the downward flow of cold air caused by reducing the rotation speed of the indoor fan 122. Thereby, it is possible to stabilize the indoor humidity distribution while suppressing the downward flow of cold air.

[0050] Note that when the second determination unit 204 determines that the indoor humidity has reached the target humidity, the drive control unit 206 maintains the rotation speed of the indoor fan 122 for a predetermined time and then increases the rotation speed of the indoor fan 122. However, it is not limited to this. For example, when it is determined that the indoor humidity has reached the target humidity, the rotation speed of the indoor fan 122 may be increased.

[0051] When the drive control unit 206 increases the rotation speed of the indoor fan 122, it increases the rotation speed until it reaches a predetermined rotation speed. The predetermined rotation speed is, for example, the rotation speed set with the rotation speed before the indoor fan 122 starts to decrease as the upper limit. The absolute value of the change in the rotation speed per unit time when increasing the rotation speed of the indoor fan 122 is, for example, 10 rpm / 60 s.

[0052] When the drive control unit 206 increases the rotation speed of the indoor fan 122, it controls the rotation speed of the indoor fan 122 so that the absolute value of the change in the rotation speed per unit time of the indoor fan 122 is smaller when the rotation speed of the indoor fan 122 is increased than when the rotation speed of the indoor fan 122 is decreased. As a result, compared with when the rotation speed of the indoor fan 122 is decreased, the rotation speed of the indoor fan 122 can be increased slowly, so that it is possible to suppress the evaporation of the moisture adhering to the indoor heat exchanger 121 due to the rapid increase in the temperature of the indoor heat exchanger 121. Therefore, it is possible to suppress the increase in the indoor humidity.

[0053] When the third determination unit 205 determines that the rotation speed of the indoor fan 122 has reached the predetermined rotation speed, the drive control unit 206 ends the dehumidification process by the control unit 200. Then, when it is determined again in the first determination unit 203 that the indoor temperature is lower than the set temperature and in the second determination unit 204 that the indoor humidity is higher than the target humidity, the control unit 200 starts the dehumidification process.

[0054] Note that when the third determination unit 205 determines that the rotation speed of the indoor fan 122 has reached a predetermined rotation speed, the drive control unit 206 ends the dehumidification process. However, it is not limited to this. For example, when the third determination unit 205 determines that a predetermined time has elapsed while continuously increasing the rotation speed of the indoor fan 122, the dehumidification process may be ended.

[0055] Also, during the dehumidification process, more specifically, when the rotation speed of the indoor fan 122 is being decreased or when the rotation speed of the indoor fan 122 is being maintained, if the first determination unit 203 determines that the indoor temperature is equal to or higher than the set temperature, the drive control unit 206 increases the rotation speed of the indoor fan 122 until it reaches the rotation speed before starting to decrease the rotation speed of the indoor fan 122 (the original rotation speed). Thereby, during the dehumidification process, when it is determined that the indoor temperature is equal to or higher than the set temperature, by returning the rotation speed of the indoor fan 122 to the original rotation speed and ending the dehumidification process, temperature control can be prioritized. Note that when the drive control unit 206 increases the rotation speed of the indoor fan 122, it may control the rotation speed of the indoor fan 122 such that the absolute value of the change amount of the rotation speed per unit time of the indoor fan 122 is smaller when increasing the rotation speed of the indoor fan 122 than when decreasing the rotation speed of the indoor fan 122.

[0056] Note that the change amount of the rotation speed per unit time when the drive control unit 206 increases or decreases the rotation speed of the indoor fan 122 is a predetermined value. However, it is not limited to this. For example, it may be changed based on the airtightness and heat insulation of the indoor space. For example, when the airtightness and heat insulation of the indoor space are high, the change amount of the rotation speed may be made smaller, and when the airtightness and heat insulation of the indoor space are low, the change amount of the rotation speed may be made larger. The change amount of the rotation speed per unit time may be changed.

[0057] The dew point temperature calculation unit 207 calculates the dew point temperature. The dew point temperature calculation unit 207 calculates the dew point temperature from the indoor temperature and the indoor humidity.

[0058] Using FIG. 5, an example of the dehumidification process during the cooling operation of the air conditioner 100 will be described. FIG. 5 is a flowchart showing an example of the dehumidification process during the cooling operation of the air conditioner 100. At the timing when the flowchart shown in FIG. 5 is started, it is assumed that the air conditioner 100 is in the cooling operation and is controlling the rotation speed of the compressor 111 so that the indoor temperature becomes the set temperature.

[0059] In S101, the first determination unit 203 determines whether the indoor temperature is lower than the set temperature. If it is determined in the first determination unit 203 that the indoor temperature is lower than the set temperature, that is, if Yes in S101, the process proceeds to S102. If it is determined in the first determination unit 203 that the indoor temperature is equal to or higher than the set temperature, that is, if No in S101, S101 is repeated.

[0060] In S102, the drive control unit 206 controls the rotation speed of the compressor 111 to a constant rotation speed and proceeds to S103.

[0061] In S103, the second determination unit 204 determines whether the indoor humidity is higher than the target humidity. If it is determined in the second determination unit 204 that the indoor humidity is higher than the target humidity, that is, if Yes in S103, the process proceeds to S104. If it is determined in the second determination unit 204 that the indoor humidity is equal to or lower than the target humidity, that is, if No in S103, S103 is repeated.

[0062] In S104, the drive control unit 206 reduces the rotation speed of the indoor fan 122 and proceeds to S105.

[0063] In S105, the second determination unit 204 determines whether the indoor humidity is equal to or lower than the target humidity. In S105, if the second determination unit 204 determines that the indoor humidity is equal to or lower than the target humidity, that is, if Yes in S105, the process proceeds to S106. In S105, if the second determination unit 204 determines that the indoor humidity is higher than the target humidity, that is, if No in S105, the process returns to S104.

[0064] In S106, the drive control unit 206 maintains the rotation speed of the indoor fan 122 for a predetermined time and proceeds to S107. Note that in S106, although the rotation speed of the indoor fan 122 is maintained for a predetermined time, it is not limited thereto, and S106 may be skipped and the process may proceed to S107 where the rotation speed of the indoor fan 122 is increased.

[0065] In S107, the drive control unit 206 increases the rotation speed of the indoor fan 122 and proceeds to S108. In S107, the drive control unit 206 controls the rotation speed of the indoor fan 122 such that the absolute value of the change amount of the rotation speed of the indoor fan 122 per unit time is smaller when the rotation speed of the indoor fan 122 is increased than when the rotation speed of the indoor fan 122 is decreased.

[0066] In S108, the third determination unit 205 determines whether or not the rotation speed of the indoor fan 122 has reached a predetermined rotation speed. In S108, when the third determination unit 205 determines that the rotation speed of the indoor fan 122 has reached the predetermined rotation speed, that is, when Yes in S108, the process returns to S101. In S108, when the third determination unit 205 determines that the rotation speed of the indoor fan 122 has not reached the predetermined rotation speed, that is, when No in S109, the process returns to S107.

[0067] FIG. 6 is an operation explanatory diagram showing an example of a dehumidification process during the cooling operation of the air conditioner 100. FIG. 6 is a time chart showing the relationship among the indoor temperature, the indoor humidity, and the rotation speed of the indoor fan 122.

[0068] First, at time t0, the control unit 200 is executing a cooling operation, and the first determination unit 203 determines that the indoor temperature is equal to or higher than the set temperature T1. From time t0 to t1, the control unit 200 controls the rotation speed of the compressor 111, the opening degree of the expansion valve 113, etc. so that the indoor temperature becomes the set temperature T1.

[0069] At time t1, the first determination unit 203 determines that the room temperature has become lower than the set temperature T1. Also, at time t1, the second determination unit 204 determines that the humidity is higher than the target humidity H1. At time t1, the drive control unit 206 sets the rotation speed of the compressor 111 to a constant rotation speed and starts to decrease the rotation speed of the indoor fan 122. From time t1 to t2, the drive control unit 206 continues to decrease the rotation speed of the indoor fan 122.

[0070] At time t2, the second determination unit 204 determines that the humidity has reached the target humidity H1. The drive control unit 206 maintains the rotation speed of the indoor fan 122 at the rotation speed when the humidity reaches the target humidity H1 for a predetermined time a from time t2 to t3. That is, the period from time t2 to t3 is the predetermined time a.

[0071] At time t3, the drive control unit 206 starts to increase the rotation speed of the indoor fan 122. From time t3 to t4, the control unit 200 continues to increase the rotation speed of the indoor fan 122.

[0072] At time t4, the third determination unit 205 determines that the rotation speed of the indoor fan 122 has reached the predetermined rotation speed R1. Since it is determined at time t4 in the second determination unit 204 that the humidity is higher than the target humidity H1, the drive control unit 206 starts the dehumidification process again and starts to decrease the rotation speed of the indoor fan 122.

[0073] In the embodiment shown in FIG. 6, the drive control unit 206 continues to decrease the rotation speed of the indoor fan 122 until the second determination unit 204 determines that the indoor humidity has reached the target humidity H1. However, the present invention is not limited to this. For example, after starting to decrease the rotation speed of the indoor fan 122, the rotation speed of the indoor fan 122 may be maintained when a predetermined condition is satisfied.

[0074] FIG. 7 is an operation explanatory diagram showing a first modification of the dehumidification process during the cooling operation of the air conditioner 100. FIG. 7 is a time chart showing the relationships among the indoor temperature, the indoor humidity, the rotation speed of the indoor fan 122, and the temperature of the indoor heat exchanger 121. In the first modification shown in FIG. 7, the description of the same configuration as in FIG. 6 is omitted.

[0075] The control unit 200 further includes a fourth determination unit that compares the temperature of the indoor heat exchanger 121 with the target temperature T2 and determines whether the temperature of the indoor heat exchanger 121 has reached the target temperature T2. When the fourth determination unit determines that the temperature of the indoor heat exchanger 121 has reached the target temperature T2 after the drive control unit 206 starts to decrease the rotation speed of the indoor fan 122, the drive control unit 206 maintains the rotation speed of the indoor fan 122. The target temperature T2 is a temperature at which the air passing through the indoor heat exchanger 121 can be sufficiently cooled. In the present embodiment, the target temperature T2 is, for example, the dew point temperature.

[0076] At time t1, the first determination unit 203 determines that the room temperature has become lower than the set temperature T1. Also, at time t1, the second determination unit 204 determines that the humidity is higher than the target humidity H1. At time t1, the drive control unit 206 sets the rotation speed of the compressor 111 to a constant rotation speed and starts to decrease the rotation speed of the indoor fan 122. At time t2, before the indoor humidity reaches the target humidity H1, the fourth determination unit determines that the temperature of the indoor heat exchanger 121 has reached the target temperature T2. From time t2 to time t3, the drive control unit 206 maintains the rotation speed of the indoor fan 122. Then, at time t3, the second determination unit 204 determines that the indoor humidity has reached the target humidity H1, and from time t3 to time t4, the drive control unit 206 maintains the rotation speed of the indoor fan 122 at the time when the indoor humidity reaches the target humidity H1 for a predetermined time a.

[0077] As described above, after starting to decrease the rotational speed of the indoor fan 122, when the temperature of the indoor heat exchanger 121 reaches the target temperature T2, the rotational speed of the indoor fan 122 is maintained. Thereby, for example, it is possible to suppress the rotational speed of the indoor fan 122 from decreasing too much, so that dehumidification can be performed while suppressing the dripping of cold air.

[0078] FIG. 8 is an operation explanatory diagram showing a second modification of the dehumidification process during the cooling operation in the air conditioner 100. FIG. 8 is a time chart showing the relationship among the indoor temperature, the indoor humidity, and the rotational speed of the indoor fan 122. In the second modification shown in FIG. 8, the description of the same configuration as in FIG. 6 is omitted.

[0079] The control unit 200 further includes a fifth determination unit that determines whether or not the rotational speed of the indoor fan 122 has reached the minimum rotational speed L1. When it is determined in the fifth determination unit that the rotational speed of the indoor fan 122 has reached the minimum rotational speed L1 after starting to decrease the rotational speed of the indoor fan 122, the drive control unit 206 maintains the rotational speed of the indoor fan 122.

[0080] At time t1, the first determination unit 203 determines that the room temperature has become lower than the set temperature T1. Also at time t1, the second determination unit 204 determines that the humidity is higher than the target humidity H1. At time t1, the drive control unit 206 sets the rotational speed of the compressor 111 to a constant rotational speed and starts to decrease the rotational speed of the indoor fan 122. Before the indoor humidity reaches the target humidity H1 at time t2, the fifth determination unit determines that the rotational speed of the indoor fan 122 has reached the minimum rotational speed L1. From time t2 to time t3, the drive control unit 206 maintains the rotational speed of the indoor fan 122 at the minimum rotational speed L1. Then, at time t3, it is determined in the second determination unit 204 that the indoor humidity has reached the target humidity H1, and from time t3 to t4, the drive control unit 206 maintains the rotational speed of the indoor fan 122 when the indoor humidity reaches the target humidity H1 for a predetermined time a.

[0081] In the above configuration, the humidity inside the room is compared with a target humidity (target humidity H1), and the rotational speed of the indoor fan 122 is increased or decreased. However, it is not limited to this. Based on whether the humidity inside the room belongs to the threshold range set by the upper limit threshold and the lower limit threshold, the rotational speed of the indoor fan 122 may be increased or decreased.

[0082] In the above configuration, the air conditioner 100 includes an indoor unit main body 120a having an air passage 120b that communicates the suction port 123 and the blowout port 124, an indoor fan 122 that blows out the air sucked from the suction port 123 through the air passage 120b from the blowout port 124, a compressor 111, and an indoor heat exchanger 121 located in the air passage 120b, and a refrigeration cycle device including these components, and a control unit 200 that controls the indoor fan 122 and the refrigeration cycle device to perform a cooling operation. In the cooling operation, when the temperature inside the room is lower than the set temperature T1 and the humidity inside the room is higher than the target humidity H1, the control unit 200 decreases the rotational speed of the indoor fan 122 without increasing the rotational speed of the compressor 111. Thereby, by reducing the amount of air passing through the indoor heat exchanger 121 per unit time, the heat exchange between the refrigerant and the indoor air can be suppressed, and the temperature of the indoor heat exchanger 121 can be lowered. Therefore, since the air passing through the indoor heat exchanger 121 can be cooled, the humidity can be lowered while maintaining the temperature inside the room at the set temperature.

[0083] In addition, when the control unit 200 satisfies a predetermined condition after starting to decrease the rotational speed of the indoor fan 122, the control unit 200 maintains the rotational speed of the indoor fan 122. The predetermined condition is that the temperature of the indoor heat exchanger 121 reaches the target temperature T2. Thereby, since it is possible to prevent the rotational speed of the indoor fan 122 from decreasing too much, the humidity can be lowered while suppressing the dripping of cold air.

[0084] After the indoor humidity reaches the target humidity H1, the control unit 200 increases the rotation speed of the indoor fan 122, and controls the indoor fan 122 such that the absolute value of the change amount of the rotation speed of the indoor fan 122 per unit time is smaller when the rotation speed of the indoor fan 122 is increased than when the rotation speed of the indoor fan 122 is decreased. Thereby, compared with when the rotation speed of the indoor fan 122 is decreased, the rotation speed of the indoor fan 122 can be increased slowly, so that it is possible to suppress the evaporation of the moisture adhering to the indoor heat exchanger 121 due to the rapid increase in the temperature of the indoor heat exchanger 121. Therefore, it is possible to suppress an increase in the indoor humidity.

[0085] Further, before increasing the rotation speed of the indoor fan 122, the control unit 200 maintains the rotation speed of the indoor fan 122 for a predetermined time when the indoor humidity becomes lower than the target humidity H1. Thereby, it is possible to stabilize the indoor humidity distribution while suppressing the downward flow of cold air.

[0086] Also, when the indoor temperature becomes higher than the set temperature T1 while the rotation speed of the indoor fan 122 is being decreased, the control unit 200 increases the rotation speed of the indoor fan 122, and controls the indoor fan 122 such that the absolute value of the change amount of the rotation speed of the indoor fan 122 per unit time is smaller when the rotation speed of the indoor fan 122 is increased than when the rotation speed of the indoor fan 122 is decreased. Thereby, when it is determined that the indoor temperature is equal to or higher than the set temperature during the dehumidification process, the rotation speed of the indoor fan 122 can be returned to the original rotation speed and the dehumidification process can be terminated, so that temperature control can be prioritized.

[0087] Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, it can be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiment, a configuration that exhibits the same operation and effect, or a configuration that can achieve the same purpose.

Explanation of Reference Numerals

[0088] 100 Air conditioner, 111 Compressor, 120a Indoor unit main body, 120b Air passage, 121 Indoor heat exchanger, 122 Indoor fan, 123 Suction port, 124 Outlet, 200 Control unit, T1 Set temperature, T2 Target temperature, H1 Target humidity

Claims

1. An indoor unit main body having an air passage communicating a suction port and a blowout port, an indoor fan that blows out air sucked from the suction port through the air passage from the blowout port, a compressor, and an indoor heat exchanger located in the air passage, a refrigeration cycle device including the same, a control unit that controls the indoor fan and the refrigeration cycle device to perform a cooling operation, and is provided with: In the cooling operation, when the indoor temperature is lower than the set temperature and the indoor humidity is higher than the target humidity, the control unit decreases the rotation speed of the indoor fan without increasing the rotation speed of the compressor. The control unit maintains the rotation speed of the indoor fan when a predetermined condition is satisfied after starting to decrease the rotation speed of the indoor fan, an air conditioner.

2. The predetermined condition is that the temperature of the indoor heat exchanger reaches the target temperature, the air conditioner according to claim 1.

3. An indoor unit main body having an air passage communicating a suction port and a blowout port, an indoor fan that blows out air sucked from the suction port through the air passage from the blowout port, a compressor, and an indoor heat exchanger located in the air passage, a refrigeration cycle device including the same, a control unit that controls the indoor fan and the refrigeration cycle device to perform a cooling operation, and is provided with: In the cooling operation, when the indoor temperature is lower than the set temperature and the indoor humidity is higher than the target humidity, the control unit decreases the rotation speed of the indoor fan without increasing the rotation speed of the compressor. After the indoor humidity reaches the target humidity, the control unit increases the rotation speed of the indoor fan. The control unit controls the indoor fan so that the absolute value of the change amount of the rotation speed of the indoor fan per unit time is smaller when the rotation speed of the indoor fan is increased than when the rotation speed of the indoor fan is decreased, an air conditioner.

4. Before increasing the rotation speed of the indoor fan, the control unit maintains the rotation speed of the indoor fan for a predetermined time when the indoor humidity is lower than the target humidity, the air conditioner according to claim 3.

5. An indoor unit main body having an air passage communicating a suction port and a blowout port, an indoor fan that blows out air sucked from the suction port through the air passage from the blowout port, a compressor, and an indoor heat exchanger located in the air passage, a refrigeration cycle device including the same, a control unit that controls the indoor fan and the refrigeration cycle device to perform a cooling operation, and is provided with: In the cooling operation, when the indoor temperature is lower than the set temperature and the indoor humidity is higher than the target humidity, the control unit decreases the rotational speed of the indoor fan without increasing the rotational speed of the compressor. When the indoor temperature becomes higher than the set temperature while the control unit is in a state of decreasing the rotational speed of the indoor fan, the control unit increases the rotational speed of the indoor fan. An air conditioner that controls the indoor fan such that the absolute value of the change amount of the rotational speed of the indoor fan per unit time is smaller when the rotational speed of the indoor fan is increased than when the rotational speed of the indoor fan is decreased.

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