JP2008190758A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform dehumidifying operation suppressing lowering of indoor temperature without complicating the structure of an air conditioner. <P>SOLUTION: This air conditioner is provided with a dehumidifying operation setting switch (33) for setting a plurality of dehumidifying request signals having different abilities for regulating required temperature. A controller (40) makes control to increase the operational capacity of the compressor (11) higher than that in the cooling operation when the humidifying request signal is set, and also makes control to throttle the opening of an expansion mechanism (17) when the humidifying request signal having lower ability for regulating required temperature among the plurality of the humidifying request signals is set. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner, and more particularly to a control technology for a dehumidifying operation.

  2. Description of the Related Art Conventionally, an air conditioner described in Patent Document 1 can be given as a device that can obtain a sufficient dehumidifying capacity in an air conditioner. The air conditioner of Patent Document 1 can increase the dehumidifying capacity when the evaporator (indoor heat exchanger) is enlarged, but the efficiency decreases, so that the indoor heat exchanger is replaced with the first indoor heat exchanger. A plurality of indoor heat exchangers are used so that the first indoor heat exchanger is a reheat heat exchanger, and the number of heat exchangers that are evaporators among the other indoor heat exchangers is appropriately selected. Thus, a desired dehumidifying ability can be obtained without lowering the room temperature.

Patent Document 2 also provides an auxiliary heat exchanger having a small heat transfer area with respect to the main indoor heat exchanger, and lowers the evaporation temperature of the auxiliary heat exchanger without causing the main indoor heat exchanger to function during the dehumidifying operation. Thus, there is disclosed an air conditioner that suppresses a decrease in indoor temperature and obtains a necessary dehumidifying capacity.
JP 2003-148830 A Japanese Patent No. 3170556

  However, the air conditioners of Patent Document 1 and Patent Document 2 require a plurality of indoor heat exchangers and expansion mechanisms, which causes a problem that the device configuration becomes complicated.

  This invention is made | formed in view of this point, The objective is to enable the dehumidification which suppressed the fall of room temperature, without making the structure of an air conditioning apparatus complicated.

  1st invention was comprised by connecting a variable capacity compressor (11), an outdoor heat exchanger (13), an expansion mechanism (17) of variable opening degree, and an indoor heat exchanger (16) in order. An air conditioner including a refrigerant circuit (10) and configured to be capable of at least a cooling operation and a dehumidifying operation is assumed.

  The air conditioner is configured to dehumidify operation setting means (33) for setting a plurality of dehumidification request signals having different required temperature control capabilities, and to cool the operating capacity of the compressor (11) when the dehumidification request signal is input. And a control means (40) for performing control to reduce the opening degree of the expansion mechanism (17) when a dehumidification request signal having a lower required temperature control capability among a plurality of dehumidification request signals is set. It is characterized by having. In the above configuration, “when the dehumidification request signal is input, the operating capacity of the compressor (11) is increased as compared with that during the cooling operation” means that during the normal cooling operation performed under the constant evaporation temperature control. It means that the capacity is larger than the maximum capacity of the compressor (11) (the maximum capacity here is smaller than the actual maximum capacity of the compressor (11)). In the present invention, the opening degree of the expansion mechanism (17) is changed according to the required temperature control ability (sensible heat treatment ability). At this time, the opening degree of the expansion mechanism (17) is changed in multiple steps or continuously. It is possible to change it.

  In the first invention, during normal cooling operation, the capacity of the compressor (11) and the opening of the expansion mechanism (17) are controlled based on the room temperature and the set temperature so that the target evaporation temperature is obtained. The refrigerant circuit (10) can be controlled. At this time, the object to be controlled is a sensible heat load (room temperature), and the latent heat load (humidity) is processed in an eventual manner.

  Next, when the dehumidification request signal is set, control is performed to increase the operating capacity of the compressor (11) as compared to the cooling operation. With this control, the evaporation temperature can be lowered. In addition, when a dehumidification request signal having a relatively low required temperature adjustment capability is set among a plurality of dehumidification request signals (when the room temperature does not have to be lowered), a dehumidification request having a relatively high required temperature adjustment capability is set. It is possible to increase the degree of superheat at the outlet of the indoor heat exchanger (16), which is an evaporator, by narrowing the opening of the expansion mechanism (17) than when the signal is set (when you want to lower the room temperature) it can. The opening of the expansion mechanism (17) may be narrowed stepwise or continuously. When the degree of superheat at the outlet of the evaporator increases, the liquid refrigerant area in the evaporator decreases and the gas refrigerant area increases. That is, the heat transfer area of the evaporator is reduced and the evaporator is apparently reduced. At this time, since the temperature of the liquid refrigerant is lowered, the amount of dehumidification can be ensured. However, since the heat transfer area is reduced, the room temperature is not excessively lowered. Therefore, by performing this control when the indoor heat load is small, dehumidification can be performed without cooling the room too much.

  On the other hand, when a dehumidification request signal having a relatively high required temperature adjustment capability among a plurality of dehumidification request signals is input, an expansion mechanism ( The degree of superheat at the outlet of the evaporator can be reduced by opening the opening of 17) in reverse. When the degree of superheat at the outlet of the evaporator decreases, the liquid refrigerant area in the evaporator increases and the gas refrigerant area decreases compared to when a dehumidification request signal having a relatively low required temperature control capability is input. . That is, it can be used without reducing the heat transfer area of the evaporator. Therefore, by performing this control when the heat load in the room is large, dehumidification can be performed while cooling the room.

  According to a second invention, in the first invention, an indoor temperature detecting means (31) for detecting an indoor temperature is provided, and the control means (40) has a capacity of the compressor (11) according to the indoor temperature. It is characterized by being configured to control stepwise or continuously.

  In the second aspect of the invention, when the dehumidification request signal is set and the operating capacity of the compressor (11) is increased as compared with that during the cooling operation, the capacity of the compressor (11) is increased stepwise or continuously. it can. Here, if the operating capacity of the compressor (11) is suddenly increased and the operation is continued, the room becomes too cold and the thermo-off state may occur, and the compressor (11) may stop. In the invention, since the evaporation temperature can be gradually lowered by changing the capacity of the compressor stepwise or continuously, it is possible to prevent the compressor (11) from stopping.

  The third invention is characterized in that, in the first or second invention, reheat means (19) for heating the air blown out from the indoor heat exchanger (16) is provided.

  As described above, in the first or second invention, when a dehumidification request signal having a relatively low required temperature control capability is set, the room is not cooled much by narrowing the opening of the expansion mechanism (17). However, if the room is still too cold, the air blown from the indoor heat exchanger (16) is heated by the reheating means (19) by adopting the configuration of the third invention. be able to.

  According to a fourth invention, in any one of the first to third inventions, when the setting of the dehumidification request signal is canceled, the control means (40) returns from the control of the dehumidifying operation to the control of the cooling operation. It is configured as described above.

  In the fourth aspect of the invention, when the setting of the dehumidification request signal is canceled, the dehumidifying operation by the superheat control is switched to the cooling operation by the constant evaporation temperature control.

  According to the present invention, the dehumidifying operation setting means (33) for setting a plurality of dehumidifying request signals having different required temperature control capabilities, and when the dehumidifying request signal is input, the operating capacity of the compressor (11) is reduced during the cooling operation. And a control means (40) for controlling the opening of the expansion mechanism (17) when a dehumidification request signal having a low required temperature control capability is set among a plurality of dehumidification request signals. Accordingly, the dehumidifying operation can be performed while cooling the room or without cooling the room too much. Moreover, in the present invention, the indoor heat exchanger (16), which is an evaporator, is apparently reduced by controlling the compressor (11) and the expansion mechanism (17) so that a desired dehumidifying operation can be performed. Since the heat exchanger (16) and the expansion mechanism (17) are not necessary, the apparatus configuration is not complicated.

  According to the second aspect of the invention, by controlling the capacity of the compressor (11) to be increased stepwise, it is possible to prevent the compressor (11) from being stopped due to the room being too cold, and the dehumidification request signal. Is set and the capacity of the compressor (11) is increased step by step, the opening degree of the expansion mechanism (17) can be adjusted accordingly. It becomes possible.

  According to the third aspect of the present invention, the reheat means (19) for heating the air blown from the indoor heat exchanger (16) is provided, so that the room can be maintained even when the opening degree of the expansion mechanism (17) is reduced. When the air is too cold, the air blown out from the indoor heat exchanger (16) is heated by the reheating means (19), thereby preventing the indoor air from being too cold.

  According to the fourth aspect of the invention, it is possible to reliably perform the cooling operation by the constant evaporation temperature control when the cooling is necessary, and the dehumidification operation by the superheat degree control when the dehumidification is necessary.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
FIG. 1 is a circuit configuration diagram showing a refrigerant circuit (10) of an air-conditioning apparatus (1) according to Embodiment 1 of the present invention. This air conditioner (1) is a so-called outdoor multi-type air conditioner (1) in which two outdoor units (3a, 3b) are connected in parallel to one indoor unit (2). The indoor unit (2) and each outdoor unit (3a, 3b) are connected by a gas side connecting pipe (4) and a liquid side connecting pipe (5). The gas side connecting pipe (4) is branched into the gas side first branch pipe (4a) and the gas side second branch pipe (4b) on the outdoor unit (3a, 3b) side, and the liquid side connecting pipe (5) On the outdoor unit (3a, 3b) side, the liquid side first branch pipe (5a) and the liquid side second branch pipe (5b) are branched.

  Each outdoor unit (3a, 3b) is installed outside the air-conditioned room (6). Each outdoor unit (3a, 3b) includes a compressor (11), a four-way switching valve (12), an outdoor heat exchanger (13), and a variable opening that are configured to have a variable operating capacity by controlling the frequency of the inverter. The outdoor expansion valve (14) comprised by the electronic expansion valve of the degree, and the accumulator (15) are provided. Although an outdoor fan is provided in the vicinity of the outdoor heat exchanger (13), the illustration is omitted.

  In each outdoor unit (3a, 3b), the compressor (11) is connected to the first port (P1) of the four-way switching valve (12) via the discharge pipe (21). The second port (P2) of the four-way selector valve (12) is connected to the gas side end of the outdoor heat exchanger (13). The compressor (11) is connected to the third port (P3) of the four-way switching valve (12) through a suction pipe (22) provided with an accumulator (15) in the middle. The fourth port (P4) of the four-way selector valve (12) is connected to the branch pipe (4a, 4b) of the gas side communication pipe (4) via the outdoor gas pipe (23).

  The four-way selector valve (12) has a first position (solid line in the figure) where the first port (P1) and the second port (P2) communicate and the third port (P3) and the fourth port (P4) communicate. Switchable to the second position (refer to the broken line in the figure) where the first port (P1) and the fourth port (P4) communicate with each other and the second port (P2) and the third port (P3) communicate with each other It is configured. The four-way selector valve (12) is set to the first position during the cooling operation and the dehumidifying operation, and is set to the second position during the heating operation.

  The liquid side end of the outdoor heat exchanger (13) is connected to the branch pipe (5a, 5b) of the liquid side communication pipe (5) via an outdoor liquid pipe (24) provided with an outdoor expansion valve (14) in the middle. )It is connected to the.

  The indoor unit (2) is installed in the air conditioning target room (6) and includes an indoor heat exchanger (16) and an indoor expansion valve (expansion mechanism) (17). The indoor expansion valve (17) is composed of a variable opening electronic expansion valve. The liquid side communication pipe (5) is connected to the liquid side end of the indoor heat exchanger (16) through an indoor liquid pipe (25) having an indoor expansion valve (17) in the middle. The gas side end of the indoor heat exchanger (16) is connected to the gas side communication pipe (4) via the indoor gas pipe (26). An indoor fan (18) is installed in the vicinity of the indoor heat exchanger (16).

  In the room of the air-conditioning target room (6), an indoor temperature sensor (31) as indoor temperature detection means and an indoor humidity sensor (32) as indoor humidity detection means are provided. Further, in this room, when the user determines that the dehumidifying operation is necessary based on the temperature and humidity in the room, the dehumidifying operation for the user to set two types of dehumidifying request signals having different required temperature control capabilities. As a setting switch (dehumidifying operation setting means) (33), an operation unit of a remote controller is provided. The dehumidifying operation setting switch (33) can set a dehumidifying request signal 1 for performing dehumidification while lowering the room temperature to some extent, and a dehumidifying request signal 2 for performing dehumidification without substantially lowering the room temperature. . That is, the dehumidifying operation of the dehumidification request signal 1 is a dehumidifying operation having a relatively high required temperature control capability, and the sensible heat load is also processed to some extent, but the dehumidifying operation of the dehumidification request signal 2 has a relative required temperature control capability. In this case, the sensible heat load is hardly processed.

  The outdoor unit (3a, 3b) includes a suction temperature sensor (34) for measuring a low-pressure refrigerant temperature in the suction pipe (22) of the compressor (11), and a high-pressure refrigerant in the discharge pipe (21) of the compressor (11). Discharge temperature sensor (35) for measuring temperature, outdoor temperature sensor (36) for measuring outdoor temperature, outdoor heat exchanger temperature sensor (37) for measuring refrigerant temperature in the outdoor heat exchanger (13), and compressor (11 ) Is provided with a high pressure switch (38) for stopping the operation of the compressor (11) when the discharge pressure rises above a predetermined value. The indoor unit (2) is provided with an indoor heat exchange temperature sensor (39) for measuring the refrigerant temperature in the indoor heat exchanger (16). In addition, illustration is abbreviate | omitted about other sensors.

  This air conditioner (1) includes a controller (40) as control means. Each controller is connected to the controller (40), and the detected value is inputted (in the figure, the connection state between the controller (40) and each sensor is omitted). The controller (40) is configured to control the operation of the refrigerant circuit (10) based on the detected temperature of the air and the refrigerant and the saturation pressure corresponding to the temperature of the refrigerant.

  The controller (40) adjusts the operating capacity of the compressor (11) and the opening of the indoor expansion valve (17) so as to obtain a target evaporation temperature during cooling operation, and performs constant evaporation temperature control. The controller (40) is connected to the dehumidifying operation setting switch (33), the compressor (11), and the indoor expansion valve (17). When the dehumidification request signal is input to the controller (40), the controller (40) stops the constant control of the evaporation temperature during the cooling operation, and the compressor (11) and the indoor expansion valve (17) Perform dehumidifying operation with different controls.

  Specifically, when a dehumidification request signal is input to the controller (40), the operating capacity of the compressor (11) is increased from the maximum capacity during cooling operation, and when the required temperature control capacity becomes low, indoor expansion occurs. Control to reduce the opening of the valve (17). In other words, among the multiple dehumidification request signals, the indoor expansion valve (17) is throttled during dehumidification operation where the required temperature adjustment capability is relatively low compared to during dehumidification operation where the required temperature adjustment capability is relatively high, and conversely the necessary temperature control When the capacity increases, control is performed to open the indoor expansion valve (17).

  When the setting of the dehumidification request signal is canceled, the controller (40) stops the dehumidifying priority operation control, and switches to normal cooling operation control by the constant evaporation temperature control.

-Driving action-
Next, the operation | movement operation | movement of this air conditioning apparatus (1) is demonstrated based on the flowchart of FIG. FIG. 2 is a flowchart showing the operation of the cooling operation and the dehumidifying operation.

  When the cooling operation is performed in step ST1 of this flow, the four-way switching valve (12) is set to the first position and the outdoor expansion valve (14) is set to fully open. Further, the operating capacity of the compressor (11) and the opening of the indoor expansion valve (17) are controlled based on the room temperature and the set temperature. During cooling operation, the gas refrigerant discharged from the compressor (11) condenses in the outdoor heat exchanger (13) to become liquid refrigerant, and is decompressed by the indoor expansion valve (17) before the indoor heat exchanger (16) Is then cycled back to the compressor (11) via the accumulator (15). During this cooling operation, the refrigerant circuit (10) is controlled by constant evaporation temperature control so that the target evaporation temperature is obtained as described above. At this time, the object to be controlled is a sensible heat load (room temperature), and the latent heat load (humidity) is processed in an eventual manner.

  In step ST2, it is determined whether or not the user has set a dehumidification request signal using the dehumidifying operation setting switch (33). When the dehumidification request signal is not input, the normal cooling operation is continued. However, when the dehumidification request signal is input, control is performed to increase the operation capacity of the compressor (11) in step ST3 as compared with the cooling operation. This control makes it possible to lower the evaporation temperature of the refrigerant than during the cooling operation.

  Next, in step ST4, it is determined whether the dehumidification request signal 1 or the dehumidification request signal 2 is input. When the dehumidification request signal 2 having a relatively low required temperature control capability is set, the process proceeds to step ST5, and the indoor expansion valve (17) is compared to when the dehumidification request signal 1 having a relatively high required temperature control capability is set. Control to reduce the opening of. In this case, in the case of this embodiment, when the degree of superheat at the outlet of the indoor heat exchanger (16) is dehumidification request signal 1, SH = 5 ° C., whereas in the case of dehumidification request signal 2, SH = 10 ° C. Become. Thus, when the degree of superheat at the outlet of the indoor heat exchanger (16), which is an evaporator, increases, the liquid refrigerant region in the indoor heat exchanger (16) decreases and the gas refrigerant region increases. For this reason, the heat transfer area of the indoor heat exchanger (16) is reduced, and the indoor heat exchanger (16) is apparently reduced. At this time, since the temperature of the liquid refrigerant is lowered, the amount of dehumidification can be ensured. However, since the heat transfer area is reduced, the room temperature is not excessively lowered. Therefore, by performing this control when the indoor heat load is small, dehumidification can be performed without cooling the room too much.

  On the other hand, when the dehumidification request signal 1 having a relatively high required temperature control capability is input, the process proceeds to step ST6, and control is performed to open the opening of the indoor expansion valve (17) compared to when the dehumidification request signal 2 is input. Do. If it carries out like this, the superheat degree of the exit of an indoor heat exchanger (16) can be reduced to SH = 5 degreeC. When the degree of superheat at the outlet of the indoor heat exchanger (16) decreases, the liquid refrigerant area in the indoor heat exchanger (16) increases and the gas refrigerant area decreases compared to when the dehumidification request signal 2 is input. become. That is, it can be used without reducing the heat transfer area of the indoor heat exchanger (16). Therefore, by performing this control when the heat load in the room is large, dehumidification can be performed while cooling the room.

  After the opening degree of the indoor expansion valve (17) is set in step ST5 or step ST6, the process returns to step ST2 to determine whether or not there is a dehumidification request signal. By doing this, as long as the dehumidification request signal is set, the dehumidifying operation of the superheat degree control is performed without returning to the normal cooling operation control, and when it is determined that the setting of the dehumidifying request signal is released, step ST1 Returning to, normal cooling operation with constant evaporation temperature control is performed.

  During the heating operation, the four-way switching valve (12) is set to the second position, the indoor expansion valve (17) is fully opened, and the opening degree of the outdoor expansion valve (14) is adjusted. During the heating operation, the gas refrigerant discharged from the compressor (11) condenses into a liquid refrigerant in the indoor heat exchanger (16), is decompressed by the outdoor expansion valve (14), and then is discharged from the outdoor heat exchanger (13). A cycle is performed that evaporates and returns to the compressor (11) via the accumulator (15).

-Effect of Embodiment 1-
According to the first embodiment, the dehumidifying operation setting switch (33) for setting a plurality of dehumidifying request signals having different required temperature control capabilities, and when the dehumidifying request signal is input, the operation capacity of the compressor (11) is set to the cooling operation. Dehumidifying operation with a controller (40) that controls the expansion mechanism to reduce the opening of the expansion mechanism when the required temperature control capacity is increased and the required temperature control capacity is reduced. It can be performed. Moreover, in the first embodiment, the dehumidifying operation that hardly controls the temperature is realized by controlling the compressor (11) and the indoor expansion valve (17), and a plurality of indoor heat exchangers (16) and indoor expansion valves ( 17) is not necessary, so the equipment configuration is not complicated.

  In Embodiment 1, the ratio of increasing the operating capacity of the compressor (11) when switching from the cooling operation with constant evaporation temperature control to the dehumidifying operation with superheat degree control is not mentioned, but the ratio is Different values may be set in advance according to temperature and humidity, and the operating capacity may be increased at an appropriate rate according to the temperature and humidity.

<< Embodiment 2 of the Invention >>
The second embodiment of the present invention is an example in which the controller (40) controls the capacity of the compressor (11) stepwise or continuously in accordance with the indoor temperature. Since the configuration of the refrigerant circuit (10) is the same as that of the first embodiment, only the operation shown in the flowcharts of FIGS. 3 and 4 will be described in the second embodiment. 3 is a flowchart showing the operation of the compressor (11) during the cooling operation and the dehumidifying operation, and FIG. 4 is a flowchart showing the operation of the indoor expansion valve (17) during the cooling operation and the dehumidifying operation. . Although the flow of operation of the compressor (11) and the flow of operation of the indoor expansion valve (17) are shown separately, control is performed simultaneously.

  In step ST11 of FIG. 3, the cooling operation by the constant evaporation temperature control is performed as in step ST1 of FIG. Also in this flow, whether or not the dehumidification request signal is set during the cooling operation is determined in step ST12, and normal cooling operation control is performed unless the dehumidification request signal is set.

  When the dehumidification request signal is input, in step ST13, control is performed to increase the operating capacity of the compressor (11) as compared to the cooling operation. In this flowchart, when there is a dehumidification request signal, an operation of increasing the operating capacity of the compressor (11) to the maximum stepwise is performed. However, the operation of the compressor (11) is restricted so that the room temperature does not drop too much with respect to the set temperature. The operation for this is shown in step ST14 to step ST19.

  In step ST13, the control level of the inverter frequency is increased by, for example, one step from the maximum value during the cooling operation. By doing so, it is possible to lower the evaporation temperature of the refrigerant than during the cooling operation.

  Next, the controller (40) confirms the presence / absence of the dehumidification request signal in step ST15 after the timer is set in step ST14 until the timer set time expires in step ST16. The user may cancel the setting of the dehumidification request signal while operating with the operation capacity of the compressor (11) being increased. In this case, the determination result in step ST15 is “NO”, so the process returns to step ST11. Then, the normal cooling operation is restored by the constant evaporation temperature control.

  On the other hand, if the set time of the timer expires while the dehumidification request signal is received after increasing the operating capacity of the compressor (11), the suction temperature of the indoor unit (2) is set to the set temperature -4 of the remote controller in step ST17. Determine if it is below ℃. If the determination result is “YES”, the room is too cold, and in step ST18, the operation capacity of the compressor (11) is reduced by one step, and then the operations in steps ST14 to ST17 are repeated. If the dehumidification request signal continues even if the timer set time expires again during this time, the determination in step ST17 is performed again. In this way, the operation can be continued while the operating capacity of the compressor (11) is gradually reduced until the suction temperature of the indoor unit (2) reaches the set temperature of the remote controller of -4 ° C or higher.

  If the determination result in step ST17 is “NO”, the process proceeds to step ST19, where it is determined whether or not the suction temperature of the indoor unit (2) is lower than the set temperature −2 ° C. of the remote controller. If the determination result is “YES”, the room is cold but not too cold, so the operations of step ST14 to step ST19 are repeated while maintaining the operating capacity of the compressor (11).

  When the determination result in step ST19 is “NO”, it is determined that dehumidification should be prioritized even if the room is still cooled, and after returning to step ST13, the operating capacity of the compressor (11) is further increased by one stage. The operations after step ST14 are repeated. By performing the operation according to the above flow, the operation capacity of the compressor (11) increases stepwise so that the room does not become too cold.

  FIG. 4 shows the control of the indoor expansion valve (17) performed simultaneously with the control of the compressor (11). The control in FIG. 4 is basically the same as the control related to the indoor expansion valve (17) in the flowchart in FIG. 2 described in the first embodiment.

  Briefly describing this flow, step ST21 is the same as step ST11 in FIG. 3, and step ST22 is the same as step ST12 in FIG. If it is determined in step ST22 that the dehumidification request signal is not input, the process returns to step ST21. If it is determined that the dehumidification request signal is input, the type of the dehumidification request signal is determined in step ST23. When the dehumidification request signal 2 is set, the process proceeds to step ST24, where the opening of the indoor expansion valve (17) is adjusted so that the refrigerant superheat degree at the outlet of the indoor heat exchanger (16) as an evaporator becomes SH = 10 ° C. To control. By doing so, dehumidification can be performed with almost no cooling in the room. If the dehumidification request signal 1 is set, the process proceeds to step ST25, and the opening degree of the indoor expansion valve (17) is controlled so that the refrigerant superheat degree becomes SH = 5 ° C. By doing so, dehumidification can be performed while the room is cooled to some extent.

-Effect of Embodiment 2-
According to the second embodiment, in addition to obtaining the same effect as in the first embodiment, when the dehumidification request signal is set and the operating capacity of the compressor (11) is increased compared to the cooling operation, the compression is performed. Since the capacity of the machine (11) is increased step by step, the following effects can be obtained. In other words, if the operation capacity of the compressor (11) is rapidly increased and the operation is continued, the room becomes too cold and the thermo-off state may occur, and the compressor (11) may stop. Since the evaporation temperature can be gradually lowered, it is possible to prevent the compressor (11) from stopping.

  Note that the operating capacity of the compressor (11) is not limited to being changed stepwise, but may be changed continuously, so that the evaporation temperature can be adjusted more finely.

<< Embodiment 3 of the Invention >>
In the third embodiment of the present invention, an electric heater (reheating means) for heating the air blown from the indoor heat exchanger (16) is provided to the air conditioner of the first embodiment. Specifically, as shown in FIG. 5, the electric heater (19) is provided in the vicinity of an air outlet (not shown) through which air that has passed through the indoor heat exchanger (16) is blown into the room.

  Other apparatus configurations are the same as those of the first embodiment.

-Driving action-
The driving operation of the third embodiment will be described based on the flowchart of FIG. FIG. 6 is a flowchart showing the operation of the cooling operation and the dehumidifying operation.

  In this flow, there is a step of turning off the electric heater (19) when the determination result is “NO” in step ST2 of FIG. 2 described in the first embodiment, and the electric power is supplied between step ST3 and step ST4 of FIG. The operation including the step of turning on the heater (19) is performed.

  In step ST31, the refrigerant circuit (10) is controlled by the evaporation temperature constant control so that the target evaporation temperature is obtained, and the humidity is processed according to the course.

  In step ST32, it is determined whether or not the user has set a dehumidification request signal using the dehumidifying operation setting switch (33). If the dehumidification request signal is not input, the normal cooling operation is continued. If the electric heater (19) is switched on at this time, the switch is turned off in step ST33.

  When the dehumidification request signal is input, in step ST34, control is performed to increase the operating capacity of the compressor (11) as compared with that during the cooling operation, and the evaporation temperature of the refrigerant is decreased as compared with that during the cooling operation. Next, in step ST35, the electric heater (19) is turned on to prevent the room from getting too cold.

  Next, in step ST36, it is determined whether the dehumidification request signal 1 or the dehumidification request signal 2 is input. When the dehumidification request signal 2 is set, the process proceeds to step ST37 to control the opening of the indoor expansion valve (17) so that the degree of superheat at the outlet of the indoor heat exchanger (16) becomes SH = 10 ° C. To. By doing so, the heat transfer area of the indoor heat exchanger (16) is reduced and the indoor heat exchanger (16) is apparently reduced, so that dehumidification can be performed without cooling the room too much. The reason why the blown air is heated by the electric heater (19) is to reliably prevent the room from getting too cold.

  On the other hand, when the dehumidification request signal 1 is input, the process proceeds to step ST38, and the opening degree of the indoor expansion valve (17) is controlled to be larger than when the dehumidification request signal 2 is input, and the indoor heat exchanger (16 ) Is reduced to SH = 5 ° C. By doing so, the indoor heat exchanger (16) can be used without reducing the heat transfer area.

  After the opening degree of the indoor expansion valve (17) is set in step ST37 or step ST38, the process returns to step ST32 to determine whether or not there is a dehumidification request signal. As a result, as long as the dehumidification request signal is set, the dehumidification operation control is performed without returning to the normal cooling operation control, and when it is determined that the setting of the dehumidification request signal is released, the normal cooling operation of step ST31 is performed. Return to.

  In the third embodiment, the operating capacity of the compressor (11) may be changed stepwise or continuously as in the second embodiment.

-Effect of Embodiment 3-
According to the third embodiment, in addition to obtaining the same effect as in the first embodiment, the electric heater (19) is provided as a reheating means for heating the air blown out from the indoor heat exchanger (16). Therefore, if the room is too cold even when the opening of the indoor expansion valve (17) is reduced, the air blown from the indoor heat exchanger (16) is heated by the electric heater (19) to cool the room. It is possible to reliably prevent overshoot.

-Modification of Embodiment 3-
In the flowchart of FIG. 6, the electric heater (19) is also turned on when the refrigerant superheat degree at the outlet of the indoor heat exchanger (16) is set to SH = 5 ° C., but at this time, the electric heater (19) is turned off. The heating ability may be weakened.

  Further, in the third embodiment, the example in which the electric heater (19) is used as the reheating means has been described. However, as long as the air can be heated, other heating devices such as a reheat heat exchanger are provided in the refrigerant circuit. May be used.

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

  For example, in each of the above embodiments, the degree of superheat at the outlet of the indoor heat exchanger (16) during the dehumidifying operation is set to two stages of opening so that SH = 5 ° C. and SH = 10 ° C. The number of dehumidification request signals may be increased. For example, in addition to SH = 5 ° C. and SH = 10 ° C., the indoor expansion valve (17) can be further throttled so that SH = 15 ° C. or SH = 20 ° C. It may be possible to adjust in more stages at narrower intervals, or to continuously adjust the degree of superheat. If it does in this way, it will become possible to perform indoor humidity adjustment more finely at the time of dehumidification operation.

  In each of the above embodiments, the remote controller operating unit operated by the user is provided indoors as the dehumidifying operation setting means (33). However, the dehumidifying operation setting means (33) is used for the temperature and humidity conditions in the room. Therefore, the controller (40) may automatically switch between the cooling operation with constant evaporation temperature control and the dehumidifying operation with superheat degree control.

  Furthermore, in each of the above embodiments, a so-called outdoor multi-type air conditioner has been described. However, the present invention is also applicable to a so-called bare machine type air conditioner in which one outdoor unit and one indoor unit are connected. In addition, even a so-called indoor multi-type air conditioner in which a plurality of indoor units are connected to one outdoor unit can be applied.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for an air conditioner that performs a dehumidifying operation with almost no decrease in temperature.

It is a circuit block diagram which shows the refrigerant circuit of the air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the operation | movement of the air_conditionaing | cooling operation and dehumidification operation in the air conditioning apparatus of Embodiment 1. FIG. It is a flowchart which shows operation | movement of the compressor at the time of the dehumidification driving | operation in the air conditioning apparatus which concerns on Embodiment 2 of this invention. 6 is a flowchart illustrating an operation of an expansion mechanism during a dehumidifying operation in the air-conditioning apparatus according to Embodiment 2. It is a circuit block diagram which shows the refrigerant circuit of the air conditioning apparatus which concerns on Embodiment 3 of this invention. It is a flowchart which shows the operation | movement of the air_conditionaing | cooling operation and dehumidification operation in the air conditioning apparatus of Embodiment 3.

Explanation of symbols

1 Air conditioner
10 Refrigerant circuit
11 Compressor
13 Outdoor heat exchanger
16 Indoor heat exchanger
17 Indoor expansion valve (expansion mechanism)
19 Heater (reheating means)
31 Indoor temperature sensor (Indoor temperature detection means)
33 Dehumidifying operation setting method
40 Controller (control means)

Claims (4)

A refrigerant circuit (10) configured by sequentially connecting a variable capacity compressor (11), an outdoor heat exchanger (13), a variable opening expansion mechanism (17), and an indoor heat exchanger (16) An air conditioner configured to be capable of at least a cooling operation and a dehumidifying operation,
Dehumidification operation setting means (33) for setting a plurality of dehumidification request signals having different required temperature control capabilities;
When the dehumidification request signal is input, the operating capacity of the compressor (11) is increased as compared with that during the cooling operation, and when a dehumidification request signal having a low required temperature control capability is set among the plurality of dehumidification request signals, the above operation is further performed. Control means (40) for controlling the opening of the expansion mechanism (17) to be reduced;
An air conditioner comprising: In claim 1,
Provided with an indoor temperature detection means (31) for detecting the indoor temperature,
The air conditioner characterized in that the control means (40) is configured to control the capacity of the compressor (11) stepwise or continuously in accordance with an indoor temperature. In claim 1 or 2,
An air conditioner comprising reheat means (19) for heating the air blown from the indoor heat exchanger (16). In any one of Claims 1-3,
The air conditioner is characterized in that the control means (40) is configured to return from the control of the dehumidifying operation to the control of the cooling operation when the setting of the dehumidification request signal is cancelled.

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