An air-conditioning apparatus having a refrigerant circuit, in which a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger are connected by a pipe and refrigerant circulates in the pipe, includes an indoor fan configured to supply an indoor air to the indoor heat exchanger, and a controller configured to control the compressor and the indoor fan. The controller is configured to run the compressor at a start of a cooling operation, start running the indoor fan at less than a set minimum wind velocity after a first set time has elapsed since the compressor started operating, run the indoor fan at the set minimum wind velocity after a second set time has elapsed since the indoor fan started operating at less than the set minimum wind velocity, and run the indoor fan at a set wind velocity after a third set time has elapsed since the indoor fan started operating at the set minimum wind velocity.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of International Patent Application No. PCT/JP2021/004865 filed on Feb. 10, 2021, which claims priority to International Patent Application No. PCT/JP2020/009379, filed on Mar. 5, 2020, the disclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an air-conditioning apparatus that performs air-conditioning in a room.

BACKGROUND

Hitherto, in an indoor unit of an air-conditioning apparatus, an unusual odor may be generated when an operation is started. Such an unusual odor is often caused by mold or dust attached to an indoor heat exchanger. It is known that such an unusual odor is generated especially when the indoor heat exchanger is getting wet and when the indoor heat exchanger is getting dry. Because an unusual odor generated in the indoor unit at the time of starting operation is caused when the indoor heat exchanger is getting wet, various techniques have been proposed recently for suppressing generation of an unusual odor when the indoor heat exchanger is getting wet.

For example, in Patent Literature 1, an air-conditioning apparatus is proposed that activates a compressor after a certain time period has elapsed after the start of a cooling operation, stops the rotation of an indoor fan during a time period when an indoor heat exchanger is getting wet, and drives the indoor fan continuously after driving the indoor fan intermittently after the indoor heat exchanger gets wet. In the air-conditioning apparatus described in Patent Literature 1, control is performed in which the indoor fan is stopped for a first time period after the start of a cooling operation and then an intermittent operation of the indoor fan is repeated. As a result, the air-conditioning apparatus drives the indoor fan after the indoor heat exchanger gets wet in some degree, and thus generation of an odor due to mold or dust attached to the indoor heat exchanger is suppressed.

PATENT LITERATURE

However, in the air-conditioning apparatus described in Patent Literature 1, because the rotation speed of a fan for an initial activation is not specified, the indoor fan is usually rotated at the wind velocity set by a user. For example, when the indoor fan is rotated while the wind velocity is set to be high, the indoor heat exchanger in a cold and wet state may be dried rapidly by a sucked warm indoor air. Consequently, when the indoor heat exchanger in the indoor unit of the air-conditioning apparatus is dried, an unusual odor may be generated.

SUMMARY

The present disclosure has been made to overcome the problem in the abovementioned related-art technique, and an object thereof is to provide an air-conditioning apparatus capable of suppressing generation of an unusual odor in an indoor unit at the start of a cooling operation.

An air-conditioning apparatus according to an embodiment of the present disclosure has a refrigerant circuit in which a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger are connected by a pipe and refrigerant circulates in the pipe, and includes an indoor fan configured to supply an indoor air to the indoor heat exchanger, and a controller configured to control the compressor and the indoor fan. The controller is configured to run the compressor at a start of a cooling operation, start running the indoor fan at less than a set minimum wind velocity after a first set time has elapsed since the compressor started operating, run the indoor fan at the set minimum wind velocity after a second set time has elapsed since the indoor fan started operating at less than the set minimum wind velocity, and run the indoor fan at a set wind velocity after a third set time has elapsed since the indoor fan started operating at the set minimum wind velocity.

According to an embodiment of the present disclosure, by gradually increasing the wind velocity of the indoor fan after the first set time has elapsed since the compressor started operating at the start of cooling operation, the indoor fan is driven while the temperature of the indoor heat exchanger is kept at a low temperature and dew is formed on the indoor heat exchanger. As a result, generation of an unusual odor can be suppressed in the indoor heat exchanger at the start of the cooling operation.

DETAILED DESCRIPTION

Embodiments according to the present disclosure will be described below with reference to the drawings. The present disclosure is not limited by the embodiments described below, and various modifications can be made without departing from the spirit of the present disclosure. Further, the present disclosure includes every possible combination of the components shown in the embodiments below. In the drawings, components denoted by the same reference signs are the same or corresponding components, and this applies to the entire description. Furthermore, although terms indicating directions (such as “top”, “bottom”, “right”, “left”, “front”, and “rear”) are used, as appropriate, to facilitate understanding, these terms are used only for the explanation purpose and do not limit the arrangement and direction of a device or a component. In addition, in terms of pressures and temperatures, the states of “high” and “low” are not determined by comparing with any specific absolute values, but are relatively determined based on a condition and an operation in a system or a device. Note that, in the drawings used in the following description, a relative size relationship among components may differ from the actual relationship and the shape of each component may differ from the actual shape.

An air-conditioning apparatus according to Embodiment 1 will be described. The air-conditioning apparatus according to Embodiment 1 is configured to perform air-conditioning by heating or cooling an air-conditioning target space by causing refrigerant to circulate in a refrigerant circuit and transferring heat between an outdoor air and an indoor air via the refrigerant.

FIG.1is a circuit diagram illustrating an example of the configuration of an air-conditioning apparatus according to Embodiment 1. As shown inFIG.1, an air-conditioning apparatus1includes an outdoor unit200, an indoor unit100, and a remote controller300. The outdoor unit200and the indoor unit100are connected to each other by a refrigerant pipe120and a refrigerant pipe130. By connecting the outdoor unit200and the indoor unit100in this way, a refrigerant circuit140through which refrigerant circulates is formed. In the refrigerant circuit140of the air-conditioning apparatus1, a compressor31, a flow switching device32, an outdoor heat exchanger33, an expansion valve34, and an indoor heat exchanger36are connected via refrigerant pipes.

The outdoor unit200includes the compressor31, the flow switching device32, the outdoor heat exchanger33, an outdoor fan35, and the expansion valve34. The outdoor unit200further includes an outdoor control device60that controls the compressor31, the flow switching device32, and the outdoor fan35.

The compressor31is configured to compress and discharge sucked refrigerant. The compressor31may include an inverter device, and may be configured so that the capacity of the compressor31can be changed by changing an operation frequency by the inverter device. Note that the capacity of the compressor31is the amount of refrigerant delivered per unit time.

The flow switching device32is, for example, a four-way valve and is configured to switch directions of a refrigerant passage. By switching refrigerant flows by the flow switching device32based on an instruction from the outdoor control device60, the air-conditioning apparatus1can achieve a heating operation or a cooling operation.

The outdoor heat exchanger33is configured to cause heat exchange to be performed between the refrigerant and an outdoor air. The outdoor heat exchanger33functions as an evaporator in heating operation to evaporate and gasify the refrigerant by causing heat exchange to be performed between the refrigerant in a low-pressure state flowing from the refrigerant pipe130and an outdoor air. The outdoor heat exchanger33functions as a condenser in a cooling operation to condense and liquefy the refrigerant by causing heat exchange to be performed between the refrigerant, which has been compressed by the compressor31and entered from the side of the flow switching device32, and an outdoor air.

The outdoor fan35is provided to improve the efficiency of heat exchange between the refrigerant and an outdoor air in the outdoor heat exchanger33. The outdoor fan35is controlled to be driven or stopped based on an instruction of the outdoor control device60. In the outdoor fan35, the rotation rate of a fan may be changed by changing the operation frequency of the fan motor based on an instruction of the outdoor control device60. In the outdoor fan35, when the rotation rate of the fan is controlled by the outdoor control device60, the velocity of wind to be supplied to the outdoor heat exchanger33is controlled.

The expansion valve34is an expansion device (flow control unit) that functions as an expansion valve by adjusting the flow rate of the refrigerant flowing through the expansion valve34. The pressure of the refrigerant is adjusted by changing the opening degree of the expansion valve34. For example, when the expansion valve34is an electronic expansion valve or a similar device, the opening degree thereof is adjusted based on an instruction of the outdoor control device60.

The outdoor control device60is housed in an electric component box, for example. The outdoor control device60is configured to control devices provided in the outdoor unit200. In the air-conditioning apparatus1according to Embodiment 1, the outdoor control device60is configured to control the compressor31, the flow switching device32, the outdoor fan35, and the expansion valve34based on instructions from an indoor control device50, which is connected to the outdoor control device60via a cable5. The indoor control device50will be described later. The outdoor control device60is an arithmetic unit, such as a microcomputer that executes software to achieve various functions, or hardware, such as circuit devices corresponding to respective functions.

The indoor unit100includes the indoor heat exchanger36and an indoor fan37. The indoor unit100also includes the indoor control device50that controls the indoor fan37.

The indoor heat exchanger36is configured to cause heat exchange to be performed between the refrigerant and an indoor air, which is air in an air-conditioning target space. The indoor heat exchanger36functions as a condenser in a heating operation to condense and liquefy the refrigerant by causing heat exchange to be performed between the refrigerant flowing from the refrigerant pipe120and the indoor air. The indoor heat exchanger36functions as an evaporator in cooling operation. The indoor heat exchanger36is configured to cause heat exchange to be performed between the refrigerant whose pressure is reduced by the expansion valve34and the indoor air to cause the refrigerant to draw heat away from the air, thereby evaporating and gasifying the refrigerant.

The indoor fan37is configured to control a flow of air to be used in heat exchange at the indoor heat exchanger36and supply the indoor air to the indoor heat exchanger36. The indoor fan37is controlled to be driven or stopped based on an instruction of the indoor control device50. In the indoor fan37, the rotation rate of a fan may be changed by changing the operation frequency of the fan motor based on an instruction of the indoor control device50. In the indoor fan37, when the rotation rate of the fan is controlled by the indoor control device50, the velocity of wind to be supplied to the indoor heat exchanger36is controlled.

Furthermore, the indoor unit100is provided with a suction temperature sensor41, a humidity sensor42, a two-phase pipe temperature sensor43, and a liquid pipe temperature sensor44. The suction temperature sensor41is configured to detect the temperature of air in the indoor space, which is the air-conditioning target space. The humidity sensor42is configured to detect the humidity in the indoor space, which is the air-conditioning target space. That is, the suction temperature sensor41and the humidity sensor42detect the temperature and the humidity of air passing through an air inlet14a(seeFIGS.5and6) of the indoor unit100. The temperature and the humidity of the air detected by the suction temperature sensor41and the humidity sensor42are output to the indoor control device50.

The two-phase pipe temperature sensor43is installed at the indoor heat exchanger36to detect the temperature of the indoor heat exchanger36. The temperature of the indoor heat exchanger36detected by the two-phase pipe temperature sensor43is output to the indoor control device50. The liquid pipe temperature sensor44is installed at the indoor heat exchanger36to detect the temperature of a heat transfer tube in which the refrigerant in a liquid state flowing into and out from the indoor heat exchanger36flows. For example, the indoor heat exchanger36may have such a configuration that the heat transfer tube has a plurality of paths, the refrigerant having flowed in the indoor heat exchanger36is divided to the plurality of paths, heat exchange is performed in in each path, flows of the divided refrigerant are merged together after heat exchange, and the merged refrigerant is discharged from the indoor heat exchanger36. In this case, the liquid pipe temperature sensor44detects the temperature of the refrigerant before being divided or after being merged. That is, because the refrigerant having passed the installation positon of the liquid pipe temperature sensor44is divided to each path through a branch pipe, the temperature of the heat transfer tube detected by the liquid pipe temperature sensor44can be used as an index of the temperature of the refrigerant immediately before the division. The temperature of the heat transfer tube detected by the liquid pipe temperature sensor44is output to the indoor control device50.

The indoor control device50is housed, as an indoor control board, in an electric component box40(seeFIGS.6and7), which will be described later. The indoor control device50is configured to control the devices provided in the indoor unit100and also control the devices provided in the outdoor unit200via the outdoor control device60, which is connected thereto by the cable5. That is, the indoor control device50is configured to control the entire air-conditioning apparatus1. In Embodiment 1, the indoor control device50performs odor suppression processing, which will be described later, while controlling the rotation rate of the indoor fan37based on detection results of the suction temperature sensor41, the humidity sensor42, and the two-phase pipe temperature sensor43. Note that details of the indoor control device50will be described later.

FIG.2is a functional block diagram illustrating an example of the configuration of the indoor control device ofFIG.1. As shown inFIG.2, the indoor control device50includes an arithmetic unit51, a comparison determination unit52, a device control unit53, a timer54, and a storage unit55. The indoor control device50is an arithmetic unit, such as a microcomputer that executes software to achieve various functions, or hardware, such as circuit devices corresponding to respective functions.

The arithmetic unit51is configured to derive a dew-point temperature based on an indoor temperature detected by the suction temperature sensor41and an indoor humidity detected by the humidity sensor42. The storage unit55stores various types of information to be used in the units of the indoor control device50. In Embodiment 1, the storage unit55stores in advance a first set time T1to a fifth set time T5to be used in the comparison determination unit52.

The first set time T1is a time period from the start of operation of the compressor31to the start of operation of the indoor fan37. The first set time T1is set to 30 seconds, for example. The second set time T2is a time period during which the indoor fan37runs at less than a set minimum wind velocity (very quiet wind). The second set time T2is set to 60 seconds, for example. The third set time T3is a time period during which the indoor fan37runs at the set minimum wind velocity (quiet wind). The third set time T3may be set to the same time period as that of the second set time T2, or may be set to a different time period, such as a longer or shorter time period than that of the second set time T2.

The fourth set time T4is a time period during which the temperature of the indoor heat exchanger36is continuously below the dew-point temperature and the indoor fan37runs at less than the set minimum wind velocity (very quiet wind). The fourth set time T4is set to a time period shorter than that of the second set time T2and shorter than that of the third set time T3. The fourth set time T4is set to 30 seconds, for example. The fifth set time T5is a time period during which the temperature of the indoor heat exchanger36is continuously below the dew-point temperature and the indoor fan37runs at the set minimum wind velocity (quiet wind). The fifth set time T5may be set to the same time period as that of the fourth set time T4, or may be set to a different time period, such as a longer or shorter time period than that of the fourth set time T4. Note that the set minimum wind velocity represents the lowest wind velocity that a user can set within an operable range of the indoor fan37.

The comparison determination unit52is configured to compare various information and make determinations based on the comparison results when performing the odor suppression processing, which will be described later. More specifically, the comparison determination unit52compares the indoor set temperature supplied from the remote controller300and a suction temperature, which is the indoor temperature, detected by the suction temperature sensor41to determine which temperature is higher. In addition, the comparison determination unit52compares the temperature of the indoor heat exchanger36detected by the two-phase pipe temperature sensor43and a dew-point temperature calculated by the arithmetic unit51to determine which temperature is higher.

The device control unit53is configured to control the rotation rate of the indoor fan37to change the wind velocity of air to be supplied to the indoor heat exchanger36from the indoor fan37based on a determination result of the comparison determination unit52. The timer54is configured to measure time from a predetermined time. Specifically, the timer54measures an operation time of the compressor31, and an operation time of the indoor fan37since the rotation rate was controlled.

FIG.3is a hardware configuration diagram illustrating an example of the configuration of the indoor control device ofFIG.2. When various functions of the indoor control device50are executed by hardware, the indoor control device50ofFIG.2is formed as a processing circuit71, as shown inFIG.3. In the indoor control device50ofFIG.2, functions of the arithmetic unit51, the comparison determination unit52, the device control unit53, the timer54, and the storage unit55are achieved by the processing circuit71.

When the functions are implemented by hardware, the processing circuit71corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination of these circuits. The indoor control device50may achieve the functions of the arithmetic unit51, comparison determination unit52, the device control unit53, the timer54and the storage unit55by respective processing circuits71or by a single processing circuit71.

FIG.4is a hardware configuration diagram illustrating another example of the configuration of the indoor control device ofFIG.2. When various functions of the indoor control device50are executed by software, the indoor control device50ofFIG.2is formed as a processor72and a memory73, as shown inFIG.4. In the indoor control device50, functions of the arithmetic unit51, the comparison determination unit52, the device control unit53, the timer54, and the storage unit55are achieved by the processor72and the memory73.

When the functions are implemented by software, the functions of the arithmetic unit51, the comparison determination unit52, the device control unit53, the timer54, and the storage unit55are achieved by software, firmware, or a combination of software and firmware in the indoor control device50. The software and the firmware are described as programs and stored in the memory73. The processor72is configured to read out and execute the programs stored in the memory73to thereby implement the functions.

The memory73is, for example, a random access memory (RAM), a read only memory (ROM), a flash memory, an erasable and programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), or other types of non-volatile or volatile semiconductor memory. In addition, the memory73may be, for example, a magnetic disk, a flexible disk, an optical disc, a compact disc (CD), a mini disc (MD), a digital versatile disc (DVD), or other types of detachable recording medium.

The air-conditioning apparatus1includes a remote controller (hereinafter referred to as “remote”)300. The remote300is used by a user to remotely control the air-conditioning apparatus1.

The remote300is connected to the indoor control device50by a remote line6. The remote300is configured to communicate with the indoor control device50via the remote line6by transmitting and receiving signals. For example, the remote300transmits a stop signal for stopping the operation of the air-conditioning apparatus1to the indoor control device50. The operations of the indoor unit100and the outdoor unit200are thus stopped. In addition, the remote300transmits a start signal for starting the operation of the air-conditioning apparatus1to the indoor control device50. The operations of the indoor unit100and the outdoor unit200are thus started.

Furthermore, the remote300can set an indoor set temperature, which is a desired indoor temperature, based on an operation of a user. The remote300transmits a signal indicating the indoor set temperature being set to the indoor control device50. Note that, the connection between the remote300and the indoor control device50is not limited to the connection using the remote line6. The remote300and the indoor control device50may be wirelessly connected, for example.

Next, the configuration of the indoor unit100will be described.FIG.5is a bottom view illustrating an example of the appearance of the indoor unit ofFIG.1.FIG.6is a schematic sectional view of the indoor unit taken along the line A-A ofFIG.5. An X-axis shown inFIG.5and the following drawings represents the right and left width direction of the indoor unit100. A Y-axis represents the front and back direction of the indoor unit100. A Z-axis represents the vertical direction of the indoor unit100. More specifically, the indoor unit100will be described with an X1 side of the X-axis as the left side and an X2 side thereof as the right side, a Y1 side of the Y-axis as the front side and a Y2 side thereof as the back side, and a Z1 side of the Z-axis as the upper side and a Z2 side thereof as the lower side. Furthermore, the description basically represents a positional relationship (for example, a relationship in the vertical direction) among the components based on the assumption that the indoor unit100is placed in an actual use state.

The indoor unit100according to Embodiment 1 is, for example, an indoor unit of a ceiling embedded type that can be embedded in a ceiling, and of a four-way cassette type in which air outlets13care formed in four directions. As shown inFIG.6, the indoor unit100has a casing10that houses the indoor fan37and the indoor heat exchanger36. The casing10has a top panel11forming a ceiling face and four side plates12forming front, back, right, and left side-faces. The casing10has an opening on a lower side (Z2 side) facing the inside of a room. On the opening of the casing10, a decorative panel13having a substantially rectangular shape in a plane view is attached, as shown inFIG.5.

The decorative panel13is a plate-like component. One face of the decorative panel13faces an attached face, such as a ceiling or a wall, and the other face faces the inside of a room, which is an air-conditioning target space. As shown inFIGS.5and6, an opening part13aas a through hole is formed near the center of the decorative panel13. A suction grill14is attached on the opening part13a. On the suction grill14, an air inlet14ais formed through which air enters the casing10from the inside of the room corresponding to an air-conditioning target space. On the casing10side of the suction grill14, a filter (not shown) for removing dust in the air having passed through the suction grill14is arranged. An air outlet13cfrom which air flows out is formed on the decorative panel13between an outer edge part13bof the decorative panel13and an inner edge part forming the opening part13a. One air outlets13cis formed along each of the four sides of the decorative panel13. That is, in the casing10, the indoor heat exchanger36and the indoor fan37are housed, and a plurality of air outlets13care formed from which air having passed through the indoor heat exchanger36is blown out by driving of the indoor fan37. In the casing10, an air passage is formed between the air inlet14aand the air outlet13c.

Each air outlet13cis provided with a vane15that changes the direction of wind flow. The indoor unit100is capable of changing the direction of wind blown out from the air outlet13cby changing the angle of the vane15. The vane15is a wind direction plate that is connected to a motor (not shown) and whose angle can be changed by the indoor control device50. By changing the angle of the vane15, the indoor control device50can open and close the air outlet13c.

FIG.7is a bottom view illustrating the indoor unit ofFIG.5without the suction grill. The indoor fan37and the indoor heat exchanger36are provided inside the casing10. The indoor fan37is configured to cause air in the room to enter the air inlet14aof the indoor unit100and cause air to flow into the room from the air outlet13cof the indoor unit100. The indoor fan37is arranged to face the suction grill14in the casing10. In addition, the indoor fan37is arranged in the casing10in such a manner that the rotation shaft is extended in the vertical direction (Z-axis direction).

In the casing10, the indoor heat exchanger36is arranged in an air passage between the indoor fan37and the air outlet13c. The indoor heat exchanger36is configured to cause heat exchange to be performed between the refrigerant flowing therein and air flowing in the air passage. By causing heat exchange to be performed between the refrigerant flowing therein and the indoor air, the indoor heat exchanger36produces air for air-conditioning. The indoor heat exchanger36is, for example, a fin-tube type heat exchanger, and is arranged to surround the indoor fan37on a downstream side of the indoor fan37in the air flow.

In the casing10, the indoor fan37and the indoor heat exchanger36are arranged on a downstream side of the air inlet14ain the air flow but on an upstream side of the air outlet13cin the air flow. In addition, in the indoor unit100, the indoor fan37is arranged above the suction grill14and the indoor heat exchanger36is arranged in a radial direction of the indoor fan37. Furthermore, in the indoor unit100, the suction grill14is arranged below the indoor heat exchanger36.

The indoor unit100also has a bell mouth16. As shown inFIGS.6and7, the bell mouth16is installed on an upstream side of the indoor fan37on the air inflow side of the indoor unit100. The bell mouth16is configured to straighten the flow of air entering from the air inlet14aof the suction grill14and then supply the air to the indoor fan37.

The indoor unit100is provided with the electric component box40between the bell mouth16and the suction grill14in the casing10. The electric component box40houses a device such as the indoor control device50. The device in the electric component box40supplies power to devices of the indoor unit100and performs transmission/reception (communication) of signals with various devices included in the air-conditioning apparatus1. The electric component box40is formed in a substantially cuboid shape. The electric component box40is arranged in the opening part13aformed on the decorative panel13, in a plane view looking up at the ceiling from the inside of the room. The longitudinal direction of the electric component box40is arranged along an edge part of the decorative panel13, the edge part forming one side of the opening part13a. The electric component box40is fixed in the casing10by a fixing component, such as a screw, for example.

The indoor unit100also has the cable5. The cable5is a communication line that is used in communication of signals including data between the indoor unit100and the outdoor unit200. However, note that the connection between the indoor unit100and the outdoor unit200is not limited to a wired connection such as the one using the cable5. The indoor unit100and the outdoor unit200may be connected via a wireless connection.

The suction temperature sensor41and the humidity sensor42are arranged between the air inlet14aand the indoor fan37. However, note that the installation positions of the suction temperature sensor41and the humidity sensor42are not limited to the position described above. The suction temperature sensor41and the humidity sensor42may be arranged at positions appropriate for detection of the indoor temperature and the indoor humidity, based on the structure of the indoor unit100.

FIG.8is a schematic view illustrating an example of a connection relationship among units in the air-conditioning apparatus according to Embodiment 1. As shown inFIG.8, the indoor unit100is connected to the outdoor unit200via the refrigerant pipe120and the refrigerant pipe130. The indoor unit100is also connected to the remote300via the remote line6.

The remote300is provided with an operation unit301and a display unit302. The operation unit301is an input device for inputting an instruction of a user into the indoor control device50of the air-conditioning apparatus1. An input method for the operation unit301is not limited to any particular method. For example, the operation unit301may be a button, a contact-type sensor or a microphone for voice input.

The display unit302displays operation conditions of the air-conditioning apparatus1based on the indoor control device50, such as an operation mode (cooling, heating, dehumidification, etc.), a set temperature, a detected room temperature, a set humidity, a detected humidity, and the current time. The display unit302is, for example, a liquid crystal display (LCD) or an organic electro luminescence (EL) display.

Next, with reference toFIG.1, operation of the air-conditioning apparatus1having the abovementioned configuration will be described together with refrigerant flows. Here, the refrigerant flow for a case where the air-conditioning apparatus1performs a cooling operation and that for a case of a heating operation will be described. InFIG.1, the solid line arrows represent the flow of the refrigerant in a cooling operation and the broken line arrows represent the flow of the refrigerant in a heating operation. Note that, the air-conditioning apparatus1is capable of performing an operation other than the cooling operation and the heating operation, such as, for example, a dehumidification operation or a ventilation operation.

When the air-conditioning apparatus1performs a cooling operation, the flow switching device32is first switched to the state indicated by the solid lines inFIG.1. That is, the flow switching device32is switched so that the discharge side of the compressor31and the outdoor heat exchanger33are connected to each other and the suction side of the compressor31and the indoor heat exchanger36are connected to each other.

When the compressor31is driven, the compressor31discharges the refrigerant in a high-temperature and high-pressure gas state. The refrigerant in a high-temperature and high-pressure gas state discharged from the compressor31flows into the outdoor heat exchanger33functioning as a condenser, via the flow switching device32. The outdoor heat exchanger33exchanges heat between the refrigerant in a high-temperature and high-pressure gas state flowing therein and an outdoor air supplied by an indoor fan35. The refrigerant in a high-temperature and high-pressure gas state is thus condensed and enters a high-pressure liquid state.

The refrigerant in a high-pressure liquid state that has flowed out from the outdoor heat exchanger33is expanded in the expansion valve34and thus enters a two-phase state in which the refrigerant in a low-pressure gas state and the refrigerant in a low-pressure liquid state are mixed. The refrigerant in a two-phase state flows into the indoor heat exchanger36functioning as an evaporator. The indoor heat exchanger36exchanges heat between the refrigerant in a two-phase state flowing therein and an indoor air supplied by the indoor fan37. The refrigerant in a liquid state of the refrigerant in a two-phase state is thus evaporated and enters a low-pressure gas state.

The refrigerant in a low-pressure gas state that has flowed out from the indoor heat exchanger36flows into the compressor31via the flow switching device32, is compressed therein, and thus enters a high-temperature and high-pressure gas state. Then, the refrigerant is discharged again from the compressor31. By repeating this cycle, the refrigerant circulates through the refrigerant circuit140as shown by the solid line arrows inFIG.1.

When the air-conditioning apparatus1performs a heating operation, the flow switching device32is first switched to the state indicated by the broken lines inFIG.1. That is, the flow switching device32is switched so that the discharge side of the compressor31and the indoor heat exchanger36are connected to each other and the suction side of the compressor31and the outdoor heat exchanger33are connected to each other.

When the compressor31is driven, the compressor31discharges the refrigerant in a high-temperature and high-pressure gas state. The refrigerant in a high-temperature and high-pressure gas state discharged from the compressor31flows into the indoor heat exchanger36functioning as a condenser, via the flow switching device32. The indoor heat exchanger36exchanges heat between the refrigerant in a high-temperature and high-pressure gas state flowing therein and the indoor air supplied by the indoor fan37. The refrigerant in a high-temperature and high-pressure gas state is thus condensed and enters a high-pressure liquid state.

The refrigerant in a high-pressure liquid state that has flowed out from the indoor heat exchanger36is expanded in the expansion valve34and thus enters a two-phase state in which the refrigerant in a low-pressure gas state and the refrigerant in a low-pressure liquid state are mixed. The refrigerant in a two-phase state flows into the outdoor heat exchanger33functioning as an evaporator. The outdoor heat exchanger33causes heat exchange to be performed between the refrigerant in a two-phase state flowing therein and outdoor air supplied by the outdoor fan35. The refrigerant in a liquid state of the refrigerant in a two-phase state is thus evaporated and enters a low-pressure gas state. The refrigerant in a low-pressure gas state that has flowed out from the outdoor heat exchanger33flows into the compressor31via the flow switching device32, is compressed therein, and thus enters a high-temperature and high-pressure gas state. Then, the refrigerant is discharged again from the compressor31. By repeating this cycle, the refrigerant circulates through the refrigerant circuit140as shown by the broken line arrows inFIG.1.

Next, odor suppression processing will be described. In the air-conditioning apparatus1according to Embodiment 1, odor suppression processing is performed to suppress generation of an unusual odor in the indoor unit100. The odor suppression processing suppresses an unusual odor generated at the start of operation of the air-conditioning apparatus1by controlling the wind velocity of the indoor fan37.

(Regarding Generation of Unusual Odor)

Before odor suppression processing is explained, a mechanism that generates an unusual odor in the indoor unit100will be described. In recent years, to achieve energy saving and improve efficiency, the capacities of indoor heat exchangers to be installed in indoor units are increased by making fin pitches smaller. Consequently, the surface area of such an indoor heat exchanger having a larger capacity is increased, and thus the amount of an oil of human skin or other oil that enters the indoor unit via the air inlet thereof and adheres to the surface area is increased. When the oil of human skin or other oil attached to the indoor heat exchanger is decomposed by microorganisms, a malodorous substance is generated in the indoor heat exchanger.

Furthermore, from a macro perspective, dust attached to an indoor heat exchanger or propagation of mold in the indoor heat exchanger causes generation of an unusual odor in the indoor heat exchanger. When a fan of an indoor unit is driven under such a condition, an unusual odor is blown out into an air-conditioning target space together with air blown out from the indoor unit. Consequently, a user can smell the unusual odor in the air supplied by the indoor unit. It is known that this unusual odor occurs when the indoor heat exchanger is getting wet and when the indoor heat exchanger is getting dry.

The odor suppression processing according to Embodiment 1 is performed to suppress generation of an unusual odor when the indoor heat exchanger36is getting wet after the air-conditioning apparatus1starts cooling operation. More specifically, in the odor suppression processing, to suppress generation of an unusual odor in the indoor unit100at the start of a cooling operation, the rotation rate of the indoor fan37is controlled in such a manner that the wind velocity is gradually increased.

(Control of Wind Velocity of Indoor Fan37)

FIG.9is a schematic view illustrating a first operation example of the indoor fan in the odor suppression processing. InFIG.9, the horizontal axis represents time. The vertical axis represents an operation state of the air-conditioning apparatus1input from the remote300, an operation state of the compressor31, and a state of wind velocity of the indoor fan37.

As shown inFIG.9, when the remote300transmits a signal (ON signal) for starting operation of the air-conditioning apparatus1at tA, operation of the compressor31is started at tB. At this moment, the indoor fan37is in a stop state. That is, no air flow is coming from the indoor unit100.

At tC, which is a time when the first set time T1has elapsed after the compressor31starts operating, operation of the indoor fan37is started. At this time, the indoor control device50controls the rotation rate of the indoor fan37so that the indoor fan37runs at less than a set minimum wind velocity (for example, “very low wind”).

Next, at tD, which is a time when the second set time T2has elapsed from tC, the indoor control device50controls the rotation rate of the indoor fan37so that the indoor fan37runs at the set minimum wind velocity (for example, “low wind”). Then, at tE, which is a time when the third set time T3has elapsed from to, the indoor control device50controls the rotation rate of the indoor fan37so that the indoor fan37runs at a set wind velocity (for example, “strong wind”). Note that, although the example ofFIG.9shows a case where the third set time T3is longer than the second set time T2, the set times are not limited thereto. The third set time T3may be shorter than or equal to the second set time T2.

FIG.10is a schematic view illustrating a second operation example of the indoor fan in the odor suppression processing. InFIG.10, the horizontal axis represents time. The vertical axis represents an operation state of the air-conditioning apparatus1input from the remote300, an operation state of the compressor31, and a state of wind velocity of the indoor fan37.

The second operation example shows a case where the wind velocity of the indoor fan37is increased to the set wind velocity in a shorter time than that of the first operation example, when it can be determined that the indoor heat exchanger36is wet. Whether or not the indoor heat exchanger36is wet can be determined by whether or not the temperature of the indoor heat exchanger36is below the dew-point temperature. Therefore, when a condition in which the temperature of the indoor heat exchanger36is kept below the dew-point temperature is known, the rotation rate of the indoor fan37is controlled according to the second operation example, and thus a time required for increasing the wind velocity of air blown from the indoor unit100to the set wind velocity can be shorten.

As shown inFIG.10, when the remote300transmits a signal (ON signal) for starting operation of the air-conditioning apparatus1at tA, the compressor31starts operating at tB. At this moment, the indoor fan37is in a stop state. That is, no air flow is coming from the indoor unit100.

At tC, which is a time when the first set time T1has elapsed after the compressor31starts operating, operation of the indoor fan37is started. At this time, the indoor control device50controls the rotation rate of the indoor fan37so that the indoor fan37runs at less than the set minimum wind velocity (for example, “very low wind”).

Next, when the temperature of the indoor heat exchanger36is kept below the dew-point temperature from tCto tF, which is a time when the fourth set time T4has elapsed from tC, the indoor control device50controls, at tF, the rotation rate of the indoor fan37so that the indoor fan37runs at the set minimum wind velocity (for example, “low wind”). Then, when the temperature of the indoor heat exchanger36is kept below the dew-point temperature from tFto tG, which a time when the fifth set time T5has elapsed from tF, the indoor control device50controls, at tG, the rotation rate of the indoor fan37so that the indoor fan37runs at the set wind velocity (for example, “high wind”). Note that, although the example ofFIG.10shows a case where the fifth set time T5is longer than the fourth set time T4, the set times are not limited thereto. The fifth set time T5may be shorter than or equal to the fourth set time T4.

FIG.11is a flowchart illustrating an example of the flow of the odor suppression processing in the air-conditioning apparatus according to Embodiment 1. Note that, the following description is made of a case where the wind velocity of the air-conditioning apparatus1is set to “high” in advance by a user.

First, after an operation of the air-conditioning apparatus1is started by operating the remote300by a user, the comparison determination unit52of the indoor control device50determines whether or not the operation mode of the air-conditioning apparatus1is a cooling operation (or a dehumidification operation) and whether or not the set temperature is lower than the suction temperature in step S1.

The comparison between the set temperature and the suction temperature is made to determine whether or not the air-conditioning apparatus1enters a thermo-on state. When the set temperature is lower than the suction temperature, a cooling operation is started and the air-conditioning apparatus1enters a thermo-on state in which the compressor31is operating. Thus, the indoor heat exchanger36is cooled and thus gets wet. Meanwhile, when the set temperature is equal to or higher than the suction temperature, a cooling operation is not started and the air-conditioning apparatus1enters a thermo-off state in which the compressor31is stopped. Thus, the indoor heat exchanger36is not cooled. Because the control in the odor suppression processing is effective when the indoor heat exchanger36is cooled and gets wet, the comparison between the set temperature and the suction temperature is made to perform the odor suppression processing when the air-conditioning apparatus1enters the thermo-on state.

When it is determined that the operation mode of the air-conditioning apparatus1is a cooling operation or a dehumidification operation and the set temperature is lower than the suction temperature (YES in step S1), the device control unit53drives the compressor31in step S2. At this time, the device control unit53causes the indoor fan37to stop its operation when the indoor fan37is operating, or the device control unit53keeps the stop state of the indoor fan37when the indoor fan37is stopped.

In step S3, the comparison determination unit52compares a time measured by the timer54with the first set time T1, which has been stored in the storage unit55in advance. Then, the comparison determination unit52determines whether or not the first set time T1has elapsed since the compressor31started operating.

When the first set time T1has elapsed (YES in step S3), the device control unit53controls the rotation rate of the indoor fan37in step S4so that the velocity of wind supplied to the indoor heat exchanger36becomes “very low”, which is less than the set minimum wind velocity. Meanwhile, when the first set time T1has not elapsed yet (NO in step S3), the processing returns to step S3to repeat the processing of step S3until the first set time T1has elapsed since the compressor31started operating.

In step S5, the comparison determination unit52compares a time measured by the timer54with the second set time T2or the fourth set time T4, which has been stored in the storage unit55in advance. Then, the comparison determination unit52determines whether or not the second set time T2has elapsed since the indoor fan37started operating at “very low” whether or not the fourth set time T4has elapsed since the indoor fan37started operating at “very low” in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature.

When it is determined that the second set time T2has elapsed since the indoor fan37started operating at “very low wind” or that the fourth set time T4has elapsed since the indoor fan37started operating at “very low,” in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature (YES in step S5), the device control unit53controls the rotation rate of the indoor fan37in step S6so that the velocity of wind supplied to the indoor heat exchanger36becomes “low”, which is the set minimum wind velocity. Meanwhile, when the second set time T2has not elapsed since the indoor fan37started operating at “very low” or the fourth set time T4has not elapsed since the indoor fan37started operating at “very low” in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature (NO in step S5), the processing returns to step S5.

Next, in step S7, the comparison determination unit52compares a time measured by the timer54with the third set time T3or the fifth set time T5, which has been stored in the storage unit55in advance. Then, the comparison determination unit52determines whether or not the third set time T3has elapsed since the indoor fan37started operating at “very low wind” or whether or not the fifth set time T5has elapsed since the indoor fan37started operating at “low” in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature.

When it is determined that the third set time T3has elapsed since the indoor fan37started operating at “low wind” or that the fifth set time T5has elapsed since the indoor fan37started operating at “low wind,” in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature (YES in step S7), the device control unit53controls the rotation rate of the indoor fan37in step S8so that the velocity of wind supplied to the indoor heat exchanger36becomes a wind velocity set by a user (for example, “high”). Meanwhile, when the third set time T3has not elapsed since the indoor fan37started operating at “low” or the fifth set time T5has not elapsed since the indoor fan37started operating at “low wind,” in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature (NO in step S5), the processing returns to step S7.

Furthermore, in step S1, when the operation mode of the air-conditioning apparatus1is not a cooling operation or a dehumidification operation or when the set temperature is equal to or above the suction temperature (NO in step S1), the indoor control device50controls the air-conditioning apparatus1to perform a normal operation in step S9.

As described above, in the odor suppression processing, when operation of the air-conditioning apparatus1starts, operation of the indoor fan37is started after the first set time T1has elapsed since the operation of the compressor31was started. Then, the rotation rate of the indoor fan37is gradually increased and thus the velocity of wind supplied to the indoor heat exchanger36is gradually increased. As a result, the indoor unit100is prevented from supplying air when the indoor heat exchanger36is getting wet immediately after the air-conditioning apparatus1starts operation. In addition, in the odor suppression processing, because, when the indoor fan37is driven, the rotation rate of the indoor fan37is controlled to be gradually increased, the wind velocity to the indoor heat exchanger36is not rapidly increased. Therefore, the indoor heat exchanger36in a wet state is not rapidly dried. Thus, the air-conditioning apparatus1according to Embodiment 1 can suppress generation of an unusual odor by performing the odor suppression processing at the start of operation.

Note that, in this example, determination is made whether or not the temperature of the indoor heat exchanger36is below the dew-point temperature based on the temperature detected by the two-phase pipe temperature sensor43, but the determination is not limited thereto. The determination may be performed based on the temperature detected by the liquid pipe temperature sensor44. Although the liquid pipe temperature sensor44detects the temperature of the refrigerant entering the indoor heat exchanger36in a cooling operation, the temperature of the liquid pipe on the inlet side of the indoor heat exchanger36is often lower than the temperature of the two-phase pipe in the indoor heat exchanger36in cooling operation. Therefore, in normal cases, it is only required to confirm that the temperature of the two-phase pipe is below the dew-point temperature. However, when the temperature of the indoor heat exchanger36is determined to be below the dew-point temperature by confirming that the temperature of the two-phase pipe or that of the liquid pipe, whichever is higher, is below the dew-point temperature for just in case, a condition where the temperature of the indoor heat exchanger36is below the dew-point temperature can be reliably detected.

As described above, in the air-conditioning apparatus1according to Embodiment 1, the indoor control device50runs the indoor fan37to gradually increase the wind velocity after the first set time T1has elapsed since the compressor31started operating at the start of a cooling operation.

In this case, the indoor control device50runs the indoor fan37at less than the set minimum wind velocity after the first set time T1has elapsed since the compressor31started operating. Furthermore, the indoor control device50runs the indoor fan37at the set minimum wind velocity after the second set time T2has elapsed since the indoor fan37started operating at less than the set minimum wind velocity or after the third set time T3has elapsed since the indoor fan37started operating at less than the set minimum wind velocity, in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature. Then, the indoor control device50runs the indoor fan37at the set wind velocity after the second set time T2has elapsed since the indoor fan37started operating at the set minimum wind velocity or after the third set time T3has elapsed since the indoor fan37started operating at the set minimum wind velocity, in a state where the temperature of the indoor heat exchanger36is kept below the dew-point temperature.

As described above, the indoor fan37is driven while the temperature of the indoor heat exchanger36is kept at a low temperature and dew is formed on the indoor heat exchanger36by gradually increasing the wind velocity of the indoor fan37. As a result, generation of an unusual odor from the indoor heat exchanger36at the start of a cooling operation can be suppressed.

Furthermore, in the air-conditioning apparatus1, because the wind velocity of the indoor fan37is gradually increased after the start of a cooling operation, the indoor heat exchanger36in a wet state is not rapidly dried. As a result, an unusual odor that may be generated when the indoor heat exchanger is getting dry can be prevented.

In the air-conditioning apparatus1, the dew-point temperature is derived based on the indoor temperature and the indoor humidity. By using these values, the indoor control device50can determine whether or not dew is formed on the indoor heat exchanger36, and thus can determine whether or not the indoor heat exchanger36is wet.

Next, Embodiment 2 will be described. Embodiment 2 differs from Embodiment 1 in that no humidity sensor42is provided in Embodiment 2. Note that, in Embodiment 2, components that are common to those in Embodiment 1 will be denoted by the same reference signs, and their detailed descriptions will be omitted.

As described in Embodiment 1, in the odor suppression processing, the dew-point temperature can be used when the wind velocity of the indoor fan37is gradually increased. In general, the dew-point temperature of the indoor air is calculated based on the temperature and the humidity of the air. For this reason, when the humidity of the indoor air cannot be detected, the dew-point temperature of the indoor air cannot be obtained. Therefore, in Embodiment 2, when the odor suppression processing is performed by using a dew-point temperature, a fictive dew-point temperature corresponding to the dew-point temperature of the indoor air is used.

Generally, a cooling operation of the air-conditioning apparatus1is performed under a usage environment expected by the manufacturer. Therefore, when a temperature equivalent to the dew-point temperature is set as a fictive dew-point temperature in the expected usage environment, processing similar to the odor suppression processing using the dew-point temperature can be performed.

Meanwhile, it is known that, under the same humidity environments, the higher the temperature of air is, the higher the dew-point temperature becomes. Furthermore, the dew-point temperature is lower than the temperature of air. Hence, when a calculated value obtained by subtracting a set temperature from the air temperature is used as a fictive dew-point temperature, dew formation on the indoor heat exchanger36can be reliably determined if the fictive dew-point temperature is lower than the actual dew-point temperature.

For instance, a case is considered where the expected usage environment of the air-conditioning apparatus1is an environment in which, for example “the indoor humidity is 40% relative humidity (RH) and the indoor temperature is from 19 to 30 degrees C.”.FIG.12is a schematic view illustrating a relationship between dew-point temperature and fictive dew-point temperature in Embodiment 2.

As shown inFIG.12, supposing that the humidity of air to be sucked into the indoor unit100is 40% RH and a usage temperature range of the air-conditioning apparatus1is from 19 to 30 degrees C., the dew point temperature is about 5.1 degrees C. when the temperature of the air is 19 degrees C., which is the lowest temperature in the usage temperature range. In addition, the dew point temperature is about 14.9 degrees C. when the temperature of the air is 30 degrees C., which is the highest temperature in the usage temperature range. Meanwhile, when a set value to be subtracted from the suction temperature, which is the indoor air temperature, is set to 16 degrees C., the fictive dew-point temperature for a case where the suction temperature is 19 degrees C. is 3 degrees C. The fictive dew-point temperature for a case where the suction temperature is 30 degrees C. is 14 degrees C.

Thus, in this example, by setting the set value to be subtracted from the air temperature to 16 degrees C., the fictive dew-point temperature becomes lower than the dew-point temperature in the usage temperature range. Therefore, when the fictive dew-point temperature obtained in this way is used in the odor suppression processing, dew formation on the indoor heat exchanger36can be reliably determined.

Note that, when the odor suppression processing is performed by using a fictive dew-point temperature, calculation for deriving the fictive dew-point temperature by subtracting the set value from the suction temperature, which is the air temperature, is performed by the arithmetic unit51in the indoor control device50. In addition, the set value to be subtracted from the suction temperature, used in the calculation in the arithmetic unit51is stored in the storage unit55in advance. As the set value for this case, a user selects an appropriate value in advance while taking the expected usage temperature range into consideration.

As described above, in the air-conditioning apparatus1according to Embodiment 2, the fictive dew-point temperature obtained by subtracting the set value from the indoor temperature is used in place of the actual dew-point temperature. As a result, as with the case of Embodiment 1, the indoor control device50can determine whether or not dew is formed on the indoor heat exchanger36, and thus can determine whether or not the indoor heat exchanger36is wet.