JPH10103743A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent deposition of dew on the surface of an air duct without enlarging the shape of the air duct. SOLUTION: In an air conditioner wherein indoor heat exchangers 16a and 16b in a refrigerating cycle equipped with a capacity-variable compressor are made evaporators and cool air subjected to heat exchange in the indoor heat exchangers 16a and 16b is supplied into an air conditioned room, by operating indoor fans 17a and 17b, through air ducts 6a and 6b provided in the ceiling, a temperature sensor 20 and a humidity sensor 21 detecting the temperature and humidity of air in the ceiling respectively are provided in an air passage 13b on one side and further a temperature sensor 24 detecting the temperature of the indoor heat exchanger 16b is provided in this heat exchanger, while a control part so constructed as to control the capacity of the compressor on the basis of the detected data of these sensors so as to change the temperature of the indoor heat exchanger 16b is provided. Thereby formation of dew on the outer surfaces of the air ducts 6a and 6b in the atmosphere in the ceiling is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner in which cool air is supplied to an air-conditioned room through a ventilation duct disposed behind a ceiling.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner in which cold air that has been heat-exchanged and sent by an evaporator built in an indoor unit is supplied to an air-conditioned room through a ventilation duct disposed above the ceiling, a ventilation system is provided. A heat insulating material is provided on the wall surface to prevent dew from adhering to the surface of the duct. Then, in order to further improve the prevention of dew adhesion on the duct surface, it is necessary to increase the thickness of the heat insulating material or use a high heat insulating material to increase the heat insulating property. However, as the thickness of the heat insulating material increases, the outside diameter of the ventilation duct becomes large, which increases the cost and makes it difficult to arrange it behind the ceiling, and when the humidity behind the ceiling is high, However, there is a risk that dew may adhere to the surface of the ventilation duct even if heat insulation is performed using a high heat insulating material.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a ventilation duct without making the shape of the ventilation duct large, so that it is inexpensive and costly. Another object of the present invention is to provide an air conditioner capable of detecting the state of air behind a ceiling with high accuracy and reliably preventing the adhesion of dew on the surface of a ventilation duct.

[0004]

An air conditioner according to the present invention comprises:
Detects the temperature of the air above the ceiling in an air conditioner that supplies cold air that has undergone heat exchange with an evaporator in a refrigeration cycle equipped with a variable capacity compressor to a room through a ventilation duct arranged above the ceiling Temperature sensor, humidity sensor that detects the humidity of the air behind the ceiling, evaporator temperature sensor that detects the temperature of the evaporator, and compression function force control that controls the capacity of the compressor based on the data detected by these sensors A means is provided.

In an air conditioner for supplying cold air, which has undergone heat exchange with an evaporator in a refrigeration cycle equipped with a variable capacity compressor, to a room through a ventilation duct disposed above and below the ceiling, the surface of the ventilation duct is A dew condensation sensor provided to detect dew condensation, and a compression function force control means for controlling the capacity of the compressor based on the detection result of the dew condensation sensor are provided.

In addition, an air conditioner is provided which has a variable air volume blower for ventilating an evaporator in a refrigeration cycle and supplies cold air exchanged with the evaporator to a room through a ventilation duct disposed above and below a ceiling. In, a temperature sensor that detects the temperature of the air behind the ceiling, a humidity sensor that detects the humidity of the air behind the ceiling, and an evaporator temperature sensor that detects the temperature of the evaporator,
A blower amount control means for controlling the blower amount of the blower based on the detection data of these sensors is provided.

In addition, an air conditioner is provided that has a variable air volume blower that ventilates an evaporator in a refrigeration cycle and supplies cold air exchanged with the evaporator to a room through a ventilation duct disposed above the ceiling. Wherein a dew condensation sensor provided to detect dew condensation on the surface of the ventilation duct, and a blowing amount control means for controlling a blowing amount of a blower based on a detection result of the dew condensation sensor are provided.

[0008] Further, the blower is characterized in that the air behind the ceiling is sucked in and blown to the evaporator.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment will be described with reference to FIGS. FIG. 1 is a view for explaining a state of air conditioning according to the present embodiment, FIG. 2 is a schematic longitudinal sectional view of an indoor unit in the present embodiment, and FIG. FIG. 4 is a schematic cross-sectional view, FIG. 4 is a flowchart relating to dew adhesion prevention control, and FIG.
Is a dew point temperature table, and FIG. 6 is a diagram for explaining release control according to the present embodiment.

In FIG. 1, reference numeral 1 denotes an air conditioner, which is constructed such that an outdoor unit 2 installed outdoors and an indoor unit 3 installed indoors are connected by a refrigerant pipe 4, and the refrigerant circulates. A compressor and an outdoor heat exchange unit (not shown) housed in the outdoor unit 2 and an expansion valve, and an indoor heat exchange unit 5 housed in the indoor unit 3 are sequentially connected in the flow direction of the refrigerant to form a refrigeration cycle. ing. From the indoor unit 3, for example, two ventilation ducts 6 having a predetermined heat insulating property so that the first room A and the second room B are air-conditioned by one unit.
The ventilation ducts 6a and 6b are connected to outlets 8a and 8b that open to the ceilings 7a and 7b of the rooms A and B, respectively. The indoor unit 3 is attached to the back side of the ceiling 7c of the corridor C between the first room A and the second room B, and the return air to the indoor unit 3 is sucked into the underside D and the inside of the corridor C. To do it. The first room A and the second room B have doors 9a and 9 provided on respective side walls.
b allows entry and exit from corridor C,
The air in each of the rooms A and B and the corridor C can be appropriately circulated.

Further, as shown in FIGS. 2 and 3, the indoor unit 3 has an indoor heat exchange section 5 provided inside a substantially rectangular parallelepiped main body case 10, and suction ports are provided on opposing side walls of the main body case 10, respectively. 11a and 11b are open and outlets 12a and 12b are formed.
The other ends of the ventilation ducts 6a, 6b are connected to 2a, 12b. The suction port 1 is provided inside the main body case 10.
Two ventilation path ducts 14a and 14b are formed so as to form two ventilation paths 13a and 13b from 1a and 11b to outlets 12a and 12b, and a partition plate 15 for partitioning the inside into two spaces. Further, the indoor heat exchanging section 5 is provided at an intermediate portion between the ventilation paths 13a and 13b so as to cross each other.
Are provided, and the ventilation paths 13a, 1 downstream of the indoor heat exchangers 16a, 16b are provided.
Indoor fans 17a and 17b are arranged in 3b.

An electric component box 18 is mounted on the upper and outer surface of the ventilation duct 14b on one side of the outlet 12b having the same heat insulation as the ventilation duct 6b. A temperature sensor 20 and a humidity sensor 21 are provided in the ventilation path 13b near 11b. The temperature sensor 20 and the humidity sensor 21 detect the suction air in the vicinity of the suction port 11b, that is, the temperature Tu and the humidity Hu of the space above the ceiling D, respectively. The temperature sensor 20 and the humidity sensor 21 are connected so that detection signals detected by the respective sensors are input to a control unit (not shown) built in the electric component box 18.

On the other hand, the control of the air conditioning operation is performed by controlling the compressor, the outdoor heat exchange section, the expansion valve, the indoor heat exchange section 5 and the like by a control signal from a control section built in the electric component box 18. Will be The control unit includes a microcomputer (not shown), in which predetermined operation control contents are programmed in advance, and the control unit includes
The operating conditions are set by the user operating the remote controllers 22a and 22b provided in the first room A and the second room B, and
The room temperature of the first room A and the second room B is detected from room temperature sensors 23a and 23b built in the remote controllers 22a and 22b, and a detection signal corresponding to the room temperature is input. The indoor heat exchanger 16b is provided with a temperature sensor 24.
A detection signal corresponding to the detected temperature Tc is input to the control unit.

Then, the remote controllers 22a, 22
When the cooling operation is started through 2b, the refrigerant discharged from the discharge port of the compressor housed in the outdoor unit 2 flows through the outdoor heat exchange unit. The refrigerant, which has become a high-temperature and high-pressure gas while flowing through the outdoor heat exchange section, is condensed and liquefied through a gas-liquid mixed state, and then is liquefied by decreasing the pressure while passing through the expansion valve. Thereafter, the refrigerant flows through the refrigerant pipe 4 and flows into the indoor heat exchanger 5 of the indoor unit 3, and evaporates by removing heat from the surroundings while flowing through the indoor heat exchangers 16a and 16b operating as evaporators. When evaporating in the indoor heat exchangers 16a and 16b, the indoor fan 1 in the ventilation paths 13a and 13b
7a and 17b are driven to form suction ports 11a and 11b.
The air inside the ceiling D and the corridor C taken from the room is deprived of heat, and the cooled air flows through the ventilation ducts 6a, 6b from the outlets 12a, 12b, and from the outlets 8a, 8b to the first room. A is blown into the second room B. Thereafter, the evaporated refrigerant returns to the suction port of the compressor.

FIG. 4 is a flowchart showing the control performed by the control unit in the course of the cooling operation to prevent the adhesion of dew to the surface of the ventilation duct. That is, the remote controller 22a, 22b
Therefore, when a cooling operation command is input, the air conditioning load is determined according to the difference between the set room temperature and the room temperature of the first room A and the second room B detected by the room temperature sensors 23a and 23b. The operating frequency Fn for driving the compressor is set at the command frequency F based on the air conditioning load at that time, and the refrigerant flows to the compressor, the outdoor heat exchange section, the expansion valve, the indoor heat exchange section 5 of the indoor unit 3, and further to the compressor. It flows in a circulating manner. Further, the indoor fans 17a and 17b of the indoor heat exchange unit 5 of the indoor unit 3 are operated at the commanded rotation speed R, and the first room A
Then, cool air is blown out to the second room B from the outlets 8a and 8b.

At the same time as the cooling operation is performed, the air behind the ceiling D is taken in from the suction ports 11a and 11b, and the temperature sensor 20 and the humidity sensor 2 are
1 detects the temperature Tu and humidity Hu of the space above the ceiling D near the suction port 11b and reads them into the control unit. Further, in step S102, the temperature Tu and the humidity Hu read from the dew point corresponding temperature table shown in FIG.
Is extracted as the temperature α corresponding to the dew point. The dew point corresponding temperature α described in the dew point corresponding temperature table is set to a temperature lower than the dew point corresponding temperature α.
When the temperature Tc of b decreases, the temperature Tu and the humidity Hu at that time have a value that may cause dew condensation on the outer surfaces of the ventilation ducts 6a and 6b.

In the next step S103, the evaporator temperature Tc is read by the temperature sensor 24 provided in the indoor heat exchanger 16b. In step S104, the dew condensation prevention flag is flag = 1 indicating that the control unit is performing dew condensation prevention control because the evaporator temperature Tc is lower than the dew point corresponding temperature α. Is determined.

During the dew condensation prevention control in step S104, f
If lag = 1, the next step S105
Then, the time t measured when the condensation prevention control is being performed by the timer built in the control unit is a predetermined time t _s ,
For example, two minutes, the state exceeding the predetermined time t _s (t
> T _s ). It should be noted that the predetermined time t _s is set in advance in minutes in the range of response times capable of operation control of the compressor. The time t is equal to the predetermined time t _s
Is exceeded, it is determined in step S106 whether or not the evaporator temperature Tc is higher (Tc> (α + 1)) than the state (α + 1) higher than the dew point corresponding temperature α by one degree. You.

If it is determined in step S106 that the evaporator temperature Tc is higher than (α + 1),
In step S107, the timer is reset to stop counting, and in the next step S108, the dew condensation prevention flag is set to flag = 0 so as to correspond to the state in which the dew condensation prevention control is stopped.

Subsequently, in step S109, the operating frequency Fn for driving the compressor is set to the command frequency F.
Proceeding to 110, it is determined whether the operating frequency Fn for driving the compressor is lower than the lowest operable frequency Fmin under the set conditions, and the operating frequency Fn is lower than the lowest frequency Fmin. The minimum frequency is restricted so as not to be the frequency, and the operation frequency Fn is made to coincide with the minimum frequency Fmin in step S111. Then, the process shifts to step S112 to drive the compressor at the operating frequency Fn of the lowest frequency Fmin matched in step S111. If it is determined in step S110 that the operating frequency Fn is equal to or higher than the minimum frequency Fmin (Fn ≧ Fmin), the process proceeds to step S112, and the compressor is driven at the operating frequency Fn.

On the other hand, when it is determined in step S104 that the flag is not in the state corresponding to flag = 1 during the dew condensation prevention control, the flow shifts to step S113 in which the evaporator temperature Tc is lower than the dew point corresponding temperature α ( It is determined whether or not Tc <α). In this step S113, the evaporator temperature Tc
Is determined to be lower than the dew point corresponding temperature α (Tc <α), the dew condensation prevention flag is set to f in step S114 to correspond to the state in which the dew condensation prevention control is performed.
lag = 1 is set.

Further, in the following step S115, a frequency corresponding to 0.9 times the operating frequency Fn for driving the compressor at that time is set to be the next highest operating frequency Fs, and the operating frequency of the compressor is set as the next operating frequency. Add frequency limits.
Then, in the next step S116, the timer is reset, and the measurement of the time t is set as a re-start. Further, the process proceeds to step S117, where the operation frequency Fn is set to the maximum operation frequency Fs, and the steps after step S110 are executed.

If it is determined in step S113 that the evaporator temperature Tc is equal to or higher than the dew point corresponding temperature α (Tc ≧ α), the dew condensation prevention control is not required, so that step S113 is performed.
Proceed to 108 to perform the subsequent steps. Furthermore, the measured time t in step S105 if it is less state for a predetermined time t _s (t ≦ t _s), the process proceeds to step S118, the whether the command frequency F is higher than the maximum operating frequency Fs Judgment is made, and the command frequency F becomes the maximum operating frequency F
If it is higher than s (F> Fs), the flow shifts to step S117, and the operation frequency Fn is set to the maximum operation frequency Fs, and the steps after step S110 are executed. Step S11
8 when the command frequency F is lower than the maximum operating frequency Fs (F
If .ltoreq.Fs), the flow shifts to step S109 to execute the subsequent steps.

If it is determined in step S106 that the evaporator temperature Tc is equal to or lower than (α + 1) (Tc ≦ (α + 1)), the flow advances to step S115 to execute the subsequent steps. = a is during condensation preventing control 1 whether to cancel the anti-condensation control every predetermined time t _s, whether the evaporator temperature Tc is returned to the dew point corresponding temperature one degree higher than the alpha (alpha + 1) state The dew condensation prevention control is released when Tc> (α + 1).

By performing the control according to the above-described flowchart, the evaporator temperature Tc and the space above the ceiling D detected by the temperature sensor 20 and the humidity sensor 21 as shown in FIG.
Is determined based on a comparison with the dew point corresponding temperature α based on the temperature Tu and the humidity Hu, the dew condensation may occur on the outer surfaces of the ventilation ducts 6a and 6b during operation. While performing release control for limiting the frequency to 0.9 times the frequency of the next maximum operation frequency Fs, the lowest operable frequency F
While the frequency limit having a lower limit of min is added, the operating frequency of the compressor is sequentially reduced to a frequency of 0.9 times the operating frequency Fn at regular intervals until the risk of dew condensation is removed, and the ventilation duct Prevent condensation on the outer surfaces of 6a and 6b. Thereafter, when there is no risk of dew condensation, the operating frequency Fn is returned to the command frequency F to operate the compressor, and desired air conditioning for each of the rooms A and B can be performed.

As described above, the air in the space above the ceiling D where the ventilation ducts 6a and 6b are disposed is taken in from the inlet 11b, the temperature Tu and the humidity Hu of the space above the ceiling D are detected, and the detected temperature Tu and humidity Hu are detected. And the compressor is operated by changing the operating frequency Fn of the compressor so that the evaporator temperature Tc becomes higher than the dew point corresponding temperature α. In particular, a thick heat insulating member layer is provided on the outer surfaces of the ventilation ducts 6a and 6b to make the shape large and a high heat insulating material is not used. Of the ventilation ducts 6a and 6b
Dew condensation on the surface can be prevented.

Next, a second embodiment will be described with reference to FIGS. FIG. 7 is a flowchart relating to dew adhesion prevention control in the present embodiment, and FIG. 8 is a diagram for explaining release control according to the present embodiment. Note that the present embodiment is different from the first embodiment only in the content of the dew / adhesion prevention control in the control unit, and the other configuration is the same. Hereinafter, control contents different from those of the first embodiment will be mainly described, and the same parts will be described with the same reference numerals with reference to the drawings according to the first embodiment.

Also in this embodiment, the control of the air conditioning operation is performed by controlling the compressor, the outdoor heat exchange section, the expansion valve, the indoor heat exchange section 5 and the like by the control signal from the control section built in the electric component box 18. This is done by: The setting of operating conditions is also performed by the user operating the remote controllers 22a and 22b provided in the first room A and the second room B, and inputting a control signal to the control unit.
The room temperature of the room A and the second room B is also detected by the room temperature sensors 23a and 23b, and a detection signal is input to the control unit.

The control by the control unit for preventing the adhesion of dew to the surface of the ventilation duct is as shown by a two-dot chain line in FIGS.
Outlet 12b having the same degree of heat insulation as ventilation duct 6b
The condensation sensor 1 is provided on the upper and outer surface of the ventilation duct 14b on one side of
9 and the detection signal is transmitted to the electrical parts box 18.
The humidity C on the outer surface of the ventilation duct 14b on the side of the outlet 12b to which the ventilation duct 6b is connected by the dew condensation sensor 19 is connected.
u% is detected, and the detected humidity Cu% is used instead of the detection signals of the temperature sensor 20 and the humidity sensor 21 in the first embodiment.

The control contents are as shown in the flowchart of FIG. That is, when a cooling operation command is input by the user from the remote controllers 22a and 22b, the set room temperature and the room temperature sensors 23a and 23a.
First room A and second room B detected by 3b
The operating frequency Fn for driving the compressor is set at the command frequency F based on the air-conditioning load at that time according to the air-conditioning load determined by the difference from the room temperature of the compressor. It flows so as to circulate to the indoor heat exchange section 5 of the unit 3 and further to the compressor. Indoor unit 3
The indoor fans 17a and 17b of the indoor heat exchange section 5 are operated at the command rotation speed R, and cool air is blown out from the outlets 8a and 8b to the first room A and the second room B.

At the same time as the cooling operation is performed, the air behind the ceiling D is taken in from the suction ports 11a and 11b.
The humidity Cu% on the outer surface of the b-side ventilation duct 14b is detected and read into the control unit. And step S202
Then, it is determined whether or not the dew condensation prevention flag is in the state of flag = 1 indicating that the dew condensation prevention control is being performed by the control unit.

During the dew condensation prevention control in step S202, f
If lag = 1, the next step S203
Then, the time t measured when the condensation prevention control is being performed by the timer built in the control unit is a predetermined time t _s ,
For example, two minutes, the state exceeding the predetermined time t _s (t
> T _s ). And time t
Exceeds the predetermined time t _s , the process proceeds to step S20.
In step 4, it is determined whether or not the humidity Cu% detected by the condensation sensor 19 is lower than 85% (Cu <85).

If the humidity Cu% is lower than 85% at the time of the determination in step S204, the timer is reset in step S205 to stop counting.
In the next step S206, the dew condensation prevention flag is set to flag = 0 so as to correspond to the state where the dew condensation prevention control is stopped.

Subsequently, in step S207, the operating frequency Fn for driving the compressor is set to the command frequency F, and further in step S207.
Proceeding to 208, it is determined whether or not the operating frequency Fn for driving the compressor is lower than the minimum operable frequency Fmin under the set conditions, and the operating frequency Fn is lower than the minimum frequency Fmin. The minimum frequency is restricted so as not to be the frequency, and the operation frequency Fn is made to coincide with the minimum frequency Fmin in step S209. Then, the process shifts to step S210 to drive the compressor at the operating frequency Fn of the lowest frequency Fmin matched in step S209. If it is determined in step S209 that the operating frequency Fn is equal to or higher than the minimum frequency Fmin (Fn ≧ Fmin), the process proceeds to step S210, and the compressor is driven at the operating frequency Fn.

On the other hand, if it is determined in step S202 that the flag is not in the state of flag = 1 during the dew condensation prevention control, the flow shifts to step S211 to reduce the humidity Cu% to 95%.
It is determined whether the state is higher (Cu> 95). If it is determined in step S211 that the humidity Cu% is higher than 95% (Cu> 95), then in step S212, the condensation prevention flag is set to flag = 1 so as to correspond to the state in which the condensation prevention control is performed. Set to the state of.

Further, in the following step S213, a frequency corresponding to 0.9 times the operating frequency Fn for driving the compressor at that time is set as the next maximum operating frequency Fs, and the operating frequency of the compressor is set as the next operating frequency. Add frequency limits.
Then, in the next step S214, the timer is reset and the measurement of the time t is set as a re-start, and the process proceeds to step S215 to set the operating frequency Fn to the maximum operating frequency Fs and execute the steps from step S208.

In step S211, the humidity Cu% is 95%.
% Or less (Cu ≦ 95), the dew condensation prevention control is unnecessary, and the process proceeds to step S206, and the subsequent steps are executed. Furthermore, the measured time t in step S203 is the case of the following conditions a predetermined time t _s (t ≦ t _s), the process proceeds to step S216, whether the command frequency F is higher than the maximum operating frequency Fs If it is determined that the command frequency F is higher than the maximum operation frequency Fs (F> Fs), the process proceeds to step S215, where the operation frequency Fn is set to the maximum operation frequency Fs, and step S215 is performed.
Perform steps 208 and beyond. In step S216, the command frequency F is lower than the maximum operating frequency Fs (F ≦ F
In the case of s), the process proceeds to step S207, and the subsequent steps are executed.

In step S204, the humidity Cu% is 85%.
When it is determined that the state is not less than% (Cu ≧ 85), the process proceeds to step S213 to execute the subsequent steps. Thus, flag = 1 dew condensation preventing control in a is whether to cancel the anti-condensation control every predetermined time t _s,
It is determined based on whether the humidity Cu% detected by the dew condensation sensor 19 has returned to a state lower than 85%, and Cu <
When it becomes 85, the dew condensation prevention control is released.

By performing the control according to the above flow chart, there is a possibility that dew condensation may occur on the outer surfaces of the ventilation ducts 6a and 6b during operation due to the determination based on the humidity Cu% detected by the dew condensation sensor 19 as shown in FIG. When it comes out, while performing the release control for adding a frequency limit to the operating frequency Fn of the compressor by 0.9 times the frequency at that time to the next maximum operating frequency Fs, at this time, the lowest operable frequency Fmin The operating frequency of the compressor is successively reduced to a frequency 0.9 times the operating frequency Fn at that time at regular intervals until the risk of dew condensation is removed, while limiting the frequency with the lower limit of , 6b to prevent condensation. That is, when the humidity Cu% detected by the dew sensor 19 becomes higher than 95%, the dew condensation prevention control is started, and when the humidity Cu% becomes lower than 85%, the dew condensation prevention control is released. Thereafter, when there is no risk of dew condensation, the operating frequency Fn is returned to the command frequency F to operate the compressor, and desired air conditioning for each of the rooms A and B can be performed.

As described above, the dew condensation sensor 19 detects the humidity C on the outer surface of the ventilation duct 14b on the side of the outlet 12b.
u% is detected, and the compressor is driven by changing the operating frequency Fn of the compressor so that the detected humidity Cu% becomes lower than a predetermined humidity. A thick heat insulating member layer is provided on the outer surface to make the shape large and a high heat insulating material is not used. Therefore, it is easy to dispose, and the cost is not increased, and the dew condensation on the surfaces of the ventilation ducts 6a and 6b is easily and accurately performed. Can be prevented.

Next, a third embodiment will be described with reference to FIG. FIG. 9 is a flowchart relating to dew adhesion prevention control in the present embodiment. The present embodiment is different from the above embodiments only in the content of dew / adhesion prevention control in the control unit, and other configurations are the same. Hereinafter, control contents different from the above embodiments will be mainly described, and the same portions will be described with the same reference numerals with reference to the drawings according to the above embodiments.

Also in the present embodiment, the compressor, the outdoor heat exchange section, the expansion valve, the indoor heat exchange section 5 and the like are controlled by the control signal from the control section built in the electric component box 18 in the control of the air conditioning operation. This is done by: The setting of operating conditions is also performed by the user operating the remote controllers 22a and 22b provided in the first room A and the second room B, and inputting a control signal to the control unit.
The room temperature of the room A and the second room B is also detected by the room temperature sensors 23a and 23b, and a detection signal is input to the control unit.

The control by the control unit for preventing the adhesion of dew on the surface of the ventilation duct is performed by controlling the ventilation passage 13b near the suction port 11b.
Tu of the space above the ceiling D detected from the measurement of the intake air by the temperature sensor 20 and the humidity sensor 21 provided in the inside
And the humidity Hu are input to a control unit built in the electric component box 18. The control content is as shown in the flowchart of FIG. That is, the remote controller 22a, 22b
Therefore, when a cooling operation command is input, the air conditioning load is determined according to the difference between the set room temperature and the room temperature of the first room A and the second room B detected by the room temperature sensors 23a and 23b. The operating frequency Fn for driving the compressor is set at the command frequency F based on the air conditioning load at that time, and the refrigerant flows to the compressor, the outdoor heat exchange section, the expansion valve, the indoor heat exchange section 5 of the indoor unit 3, and further to the compressor. It flows in a circulating manner. Further, the indoor fans 17a and 17b of the indoor heat exchange unit 5 of the indoor unit 3 are operated at the commanded rotation speed R, and the first room A
Then, cool air is blown out to the second room B from the outlets 8a and 8b.

At the same time as the cooling operation is performed, the air behind the ceiling D is taken in from the suction ports 11a and 11b, and the temperature sensor 20 and the humidity sensor 2
1 detects the temperature Tu and humidity Hu of the space above the ceiling D near the suction port 11b and reads them into the control unit. Further, in step S302, the temperature Tu and the humidity Hu read from the dew point corresponding temperature table shown in FIG.
Is extracted as the temperature α corresponding to the dew point. Subsequently, in the next step S303, the evaporator temperature Tc is read by the temperature sensor 24 provided in the indoor heat exchanger 16b. Then, in step S304, it is determined whether or not the condensation prevention flag is in the state of flag = 1 indicating that the condensation prevention control is being performed.

During dew condensation prevention control in the previous step S304, f
If lag = 1, the next step S305
The time t _1, which measures the time during which the dew condensation prevention control is being performed by the timer built in the control unit, is equal to a predetermined time t.
_s1, for example, for 10 seconds, the decision whether or not the state has exceeded a predetermined time _{t s1 (t 1> t s1} ) is made. It should be noted that the predetermined time _ts1 is the time when the indoor fans 17a, 17
It is preset in units of ten seconds within a response time range in which the number of rotations b can be controlled. When the time t ₁ exceeds the predetermined time t _s1 , subsequently, in step S306, the state where the evaporator temperature Tc is higher than the state (α + 1) which is one degree higher than the dew point corresponding temperature α (Tc> (α + 1)). Is determined.

If the evaporator temperature Tc is higher than (α + 1) at the time of the determination in step S306, the timer is reset and the counting is stopped in step S307, and the dew condensation preventing control is performed in the next step S308. The flag for dew condensation prevention is set to flag = 0 so as to correspond to the state where is stopped. That is, during the dew condensation prevention control with flag = 1, it is determined whether or not the dew condensation prevention control should be canceled every predetermined time _ts1 by returning to the (α + 1) state where the evaporator temperature Tc is higher by one degree than the dew point corresponding temperature α. A determination is made based on whether or not the dew condensation prevention control is released when Tc> (α + 1). Then, in step S309, the indoor fan 1
The rotation speeds Rn of the rotation speeds 7a and 17b are set as the commanded rotation speed R, and the process proceeds to step S310 to set the rotation speed R equal to the commanded rotation speed R
n, the indoor fans 17a and 17b are rotationally driven.

On the other hand, if it is determined in step S304 that the flag is not in the state corresponding to flag = 1 during the dew condensation prevention control, the flow shifts to step S311, where the evaporator temperature Tc is lower than the dew point corresponding temperature α ( It is determined whether or not Tc <α). In this step S311, the evaporator temperature Tc
Is determined to be lower than the dew point corresponding temperature α (Tc <α), in step S312, the dew condensation prevention flag is set to f so as to correspond to the state in which the dew condensation prevention control is performed.
lag = 1 is set.

Further, in the following step S313, the rotation speed Rn of the indoor fans 17a and 17b at that time is set to 1.1.
The rotation speed corresponding to the double is set as the rotation speed Rn in the next time. Then, in the next step S314, the timer is reset, and the measurement of the time t ₁ is set as a re-start.
In 315, the maximum rotation speed Rmax in the range where the rotation speed Rn is set, for example, in the case where the rotation speed is changed by tap switching, it is determined whether or not the rotation speed is higher than the rotation speed in the Hi tap corresponding to the maximum rotation speed. Is performed, and the maximum rotation speed Rmax is set so that the rotation speed Rn does not become larger than the maximum rotation speed Rmax.
A rotation speed limit with x as an upper limit is added. And step S
If it is determined at 315 that the rotation speed Rn is larger than the maximum rotation speed Rmax (Rn> Rmax), then at step S316, the rotation speed Rn is reduced to the maximum rotation speed Rmax.
x, and further proceeds to step S310, in which the number of rotations of the indoor fan 17 is adjusted to the maximum rotation speed Rmax.
a and 17b are rotationally driven. In step S315, the state where the rotational speed Rn is equal to or less than the maximum rotational speed Rmax (Rn ≦ Rma
x), the process proceeds to step S310, and the indoor fans 17a, 17b
Is driven to rotate.

If it is determined in step S311 that the evaporator temperature Tc is equal to or higher than the dew point corresponding temperature α (Tc ≧ α), the dew condensation prevention control is not required, so that step S311 is not necessary.
Proceed to 309 to execute the subsequent steps. Furthermore, the measured time t ₁ at step S305 the predetermined time t _s1
If the following condition (t ₁ ≦ t _s1 ) is satisfied, the process proceeds to step S317, and it is determined whether or not the command speed R is higher than the current speed Rn (R> Rn). If the command rotation speed R is higher than the rotation speed Rn at that time (R> Rn), the process shifts to step S309 to set the rotation speed to R
n is made equal to the commanded rotation speed R, and the process proceeds to step S310, where the indoor fans 17a,
17b is rotationally driven. Also, in step S317, the state where the commanded rotation speed R is less than or equal to the rotation speed Rn at that time (R ≦
If it is (Rn), the process proceeds to step S310, and the indoor fans 17a and 17b are driven to rotate at the rotation speed Rn at that time.

If it is determined in step S306 that the evaporator temperature Tc is equal to or less than (α + 1) (Tc ≦ (α + 1)), the process proceeds to step S313 to execute the subsequent steps. Although the target is different, as in the first embodiment, whether or not the condensation prevention control should be canceled every predetermined time _ts1 during the condensation prevention control where flag = 1 is determined by determining whether the evaporator temperature Tc is the dew point corresponding temperature α. One degree higher (α
+1) A decision is made based on whether or not the condition has been restored, and when Tc> (α + 1), the dew condensation prevention control is released.

By performing the control according to the above-described flowchart, the determination based on the comparison between the evaporator temperature Tc and the dew point corresponding temperature α due to the temperature Tu of the ceiling D and the humidity Hu detected by the temperature sensor 20 and the humidity sensor 21 is performed. If there is a possibility that dew condensation may occur on the outer surfaces of the ventilation ducts 6a and 6b during operation, the number of rotations Rn of the indoor fans 17a and 17b is set to 1.1 times the next number of rotations Rn, and the maximum number of rotations is set as the next number of rotations. The indoor fans 17a and 17b are controlled so that the rotation speed becomes 1.1 times the rotation speed at that time until the dew condensation is eliminated while performing release control for limiting the rotation speed with an upper limit of several Rmax. Increase the rotation speed of
The amount of heat exchange with the indoor heat exchangers 16a, 16b for a unit amount of air is reduced to increase the temperature of the cool air in the ventilation ducts 6a, 6b so that dew condensation does not occur on the outer surfaces of the ventilation ducts 6a, 6b. . Thereafter, when the risk of dew condensation disappears, the rotation speed Rn is returned to the command rotation speed R, and the indoor fan 1
The desired air conditioning for each of the rooms A and B can be performed by rotating the 7a and 17b.

As described above, the temperature Tu and the humidity Hu of the ceiling D are detected by taking in the air in the ceiling D where the ventilation ducts 6a and 6b are disposed from the suction port 11b, and the detected temperature Tu and humidity Hu are detected. To obtain the dew point corresponding temperature α at which dew condensation occurs in the atmosphere, and the indoor fans 17a and 17b so that the evaporator temperature Tc becomes higher than the dew point corresponding temperature α.
Of the indoor heat exchangers 16a, 16b
In order to reduce the amount of heat exchange in the air ducts 6a and 6b, a thick heat insulating member layer is provided on the outer surface to increase the size of the heat insulating member, without using a high heat insulating material. It does not become high, and it is possible to detect the state of the air behind the ceiling D easily and with high accuracy and to reliably prevent dew condensation on the surfaces of the ventilation ducts 6a and 6b.

Next, a fourth embodiment will be described with reference to FIG. FIG. 10 is a flowchart relating to dew adhesion prevention control in the present embodiment. The present embodiment is different from the above embodiments only in the content of dew / adhesion prevention control in the control unit, and other configurations are the same. Hereinafter, control contents different from the above embodiments will be mainly described, and the same portions will be described with the same reference numerals with reference to the drawings according to the above embodiments.

Also in this embodiment, the control of the air conditioning operation is performed by controlling the compressor, the outdoor heat exchange unit, the expansion valve, the indoor heat exchange unit 5 and the like by the control signal from the control unit built in the electric component box 18. This is done by: The setting of operating conditions is also performed by the user operating the remote controllers 22a and 22b provided in the first room A and the second room B, and inputting a control signal to the control unit.
The room temperature of the room A and the second room B is also detected by the room temperature sensors 23a and 23b, and a detection signal is input to the control unit.

The control unit controls the prevention of dew adhesion on the surface of the ventilation duct by controlling the humidity detected by the dew condensation sensor 19 provided on the outer surface of the ventilation duct 14b on the side of the outlet 12b to which the ventilation duct 6b is connected. This is executed by inputting Cu% to a control unit built in the electric component box 18. The control content is as shown in the flowchart of FIG. That is, when a cooling operation command is input by the user from the remote controllers 22a and 22b, the set room temperature and the room temperature sensors 23a and 23a.
First room A and second room B detected by 3b
The operating frequency Fn for driving the compressor is set at the command frequency F based on the air-conditioning load at that time according to the air-conditioning load determined by the difference from the room temperature of the compressor. It flows so as to circulate to the indoor heat exchange section 5 of the unit 3 and further to the compressor. Indoor unit 3
The indoor fans 17a and 17b of the indoor heat exchange section 5 are operated at the command rotation speed R, and cool air is blown out from the outlets 8a and 8b to the first room A and the second room B.

At the same time as the cooling operation is performed, the air behind the ceiling D is taken in from the inlets 11a and 11b, and the outlet 12 is detected by the condensation sensor 19 in step S401.
The humidity Cu% on the outer surface of the b-side ventilation duct 14b is detected and read into the control unit. Then, in step S402, it is determined whether or not the dew condensation prevention flag is in the state of flag = 1 indicating that the dew condensation prevention control is being performed by the control unit.

During the dew condensation prevention control in this step S402, f
If the flag lag = 1, the next step S403
The time t _1, which measures the time during which the dew condensation prevention control is being performed by the timer built in the control unit, is equal to a predetermined time t.
_s1, for example, for 10 seconds, the decision whether or not the state has exceeded a predetermined time _{t s1 (t 1> t s1} ) is made. If the time t ₁ exceeds the predetermined time t _s1 , it is determined in step S404 whether or not the humidity Cu% detected by the dew sensor 19 is lower than 85% (Cu <85). Done.

If the humidity Cu% is lower than 85% at the time of the determination in step S404, the timer is reset in step S405 to stop counting.
In the next step S406, the dew condensation prevention flag is set to flag = 0 so as to correspond to the state in which the dew condensation prevention control is stopped.

Subsequently, in step S407, the indoor fan 17
The rotation speed Rn of the rotation speeds a and 17b is set as the command rotation speed R, and the process further proceeds to step S408, where the rotation speed Rn is equal to the command rotation speed R.
To rotate the indoor fans 17a and 17b.

On the other hand, if it is determined in step S402 that the flag is not in the state of flag = 1 during the dew condensation prevention control, the flow shifts to step S409 to reduce the humidity Cu% to 95%.
It is determined whether the state is higher (Cu> 95). If it is determined in step S409 that the humidity Cu% is higher than 95% (Cu> 95), then in step S410, the dew condensation prevention flag is set to flag = 1 so as to correspond to the state where dew condensation prevention control is performed. Set to the state of.

Further, in the following step S411, the rotation speed Rn of the indoor fans 17a and 17b at that time is set to 1.1.
The rotation speed corresponding to the double is set as the rotation speed Rn in the next time. Then, in the next step S412, the timer is reset, and the measurement of the time t ₁ is set as a re-start.
The program proceeds to 315, where it is determined whether or not the rotation speed Rn is greater than the maximum rotation speed Rmax in the set range. The maximum rotation speed Rmax is set as an upper limit so that the rotation speed Rn does not become larger than the maximum rotation speed Rmax. Add a speed limit.
Then, in step S413, the rotation speed Rn is changed to the maximum rotation speed Rma.
If it is determined that the state is larger than x (Rn> Rmax), the rotation speed Rn is made to coincide with the maximum rotation speed Rmax in the following step S414, and further, in step S408.
Then, the indoor fans 17a and 17b are driven to rotate at the rotation speed Rn that matches the maximum rotation speed Rmax. If it is determined in step S413 that the rotation speed Rn is equal to or less than the maximum rotation speed Rmax (Rn ≦ Rmax), the process proceeds to step S408, and the indoor fans 17a and 17b are rotationally driven at the same rotation speed Rn. .

In step S409, the humidity Cu% is 95%.
% Or less (Cu ≦ 95), the dew condensation prevention control is unnecessary, and the process proceeds to step S407, and the subsequent steps are executed. Furthermore, the measured time t ₁ at step S403 is when a predetermined time t _s1 the following state (t ₁ ≦ t _s1), the process proceeds to step S415, the command rotational speed R is higher than the rotational speed Rn at that time It is determined whether or not the state (R> Rn) has been reached, and if the commanded rotational speed R is higher than the current rotational speed Rn (R> R)
In n), the process proceeds to step S407 to make the rotational speed Rn equal to the commanded rotational speed R, and proceeds to step S408 to rotate the indoor fans 17a and 17b at a rotational speed Rn equal to the commanded rotational speed R. If it is determined in step S415 that the commanded rotation speed R is in a state of being less than or equal to the rotation speed Rn at that time (R ≦ Rn), the process proceeds to step S408 and the rotation speed R at that time is determined.
The indoor fans 17a and 17b are rotationally driven by n.

In step S404, the humidity Cu% is 85%.
If it is determined that the state is not less than% (Cu ≧ 85), the process proceeds to step S411 to execute the subsequent steps. In this way, during the condensation prevention control with flag = 1, it is determined whether or not the condensation prevention control should be canceled every predetermined time _{ts1 by} determining whether or not the humidity Cu% detected by the condensation sensor 19 has returned to a state lower than 85%. Is determined based on
When u <85, the dew condensation prevention control is released.

By performing the control according to the above flow chart, if there is a possibility that dew condensation will occur on the outer surfaces of the ventilation ducts 6a and 6b during operation based on the determination based on the humidity Cu% detected by the dew sensor 19, the indoor Fan 17a,
While performing release control in which the rotation speed Rn of 17b is set to 1.1 times the rotation speed as the next rotation speed Rn and the rotation speed is limited to the maximum rotation speed Rmax as an upper limit, a certain period of time until the fear of dew condensation is released. Each time, the number of rotations of the indoor fans 17a, 17b is sequentially increased so that the number of rotations becomes 1.1 times the number of rotations at that time, and heat with the indoor heat exchangers 16a, 16b, which are evaporators, for a unit amount of air. The exchange amount is reduced to increase the temperature of the cold air in the ventilation ducts 6a and 6b,
In order to prevent dew condensation on the outer surfaces of a and 6b. That is, when the humidity Cu% detected by the dew sensor 19 becomes higher than 95%, the dew condensation prevention control is started, and when the humidity Cu% becomes lower than 85%, the dew condensation prevention control is released. Thereafter, when there is no risk of dew condensation, the rotation speed Rn is returned to the command rotation speed R, and the indoor fans 17a and 17b are driven to rotate, whereby desired air conditioning for the rooms A and B can be performed.

As described above, the dew condensation sensor 19 detects the humidity C on the outer surface of the ventilation duct 14b on the side of the outlet 12b.
u% is detected and the detected humidity Cu% is driven by changing the rotation speed of the indoor fans 17a and 17b so as to be lower than a predetermined humidity. In particular, the outer surfaces of the ventilation ducts 6a and 6b are formed. No thick insulation layer is used to make the shape large, and no high insulation material is used. Therefore, it is easy to dispose, the cost is not increased, and dew condensation on the surfaces of the ventilation ducts 6a and 6b is easily and accurately prevented. can do.

[0067]

As is clear from the above description, according to the present invention, the ventilation duct can be easily arranged without increasing the cost, without using a large-sized ventilation duct or using a high heat-insulating material. This has the effect of preventing dew condensation on the surface.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a state of air conditioning according to a first embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view of the indoor unit according to the first embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of the indoor unit according to the first embodiment of the present invention.

FIG. 4 is a flowchart relating to dew adhesion prevention control according to the first embodiment of the present invention.

FIG. 5 is a dew point temperature table according to the first embodiment of the present invention.

FIG. 6 is a diagram for explaining release control according to the first embodiment of the present invention.

FIG. 7 is a flowchart relating to dew adhesion prevention control according to a second embodiment of the present invention.

FIG. 8 is a diagram for explaining release control according to a second embodiment of the present invention.

FIG. 9 is a flowchart relating to dew adhesion prevention control in a third embodiment of the present invention.

FIG. 10 is a flowchart related to dew adhesion prevention control in a fourth embodiment of the present invention.

[Description of Signs] 3 Indoor unit 6a, 6b Vent duct 13a, 13b Vent path 14a, 14b Vent duct 16a, 16b Indoor heat exchanger 17a, 17b Indoor fan 18 Electrical box 19 Dew condensation Sensors 20, 24: Temperature sensor 21: Humidity sensor

Claims (5)

[Claims] 1. An air conditioner for supplying cold air, which has been heat-exchanged with an evaporator in a refrigeration cycle having a variable capacity compressor, to a room through a ventilation duct disposed above the ceiling, wherein: A temperature sensor for detecting the temperature of the air, a humidity sensor for detecting the humidity of the air behind the ceiling, an evaporator temperature sensor for detecting the temperature of the evaporator, and the compressor based on detection data of these sensors. An air conditioner comprising a compression function force control means for controlling the capacity of the air conditioner. 2. An air conditioner for supplying cold air heat exchanged with an evaporator in a refrigeration cycle equipped with a variable capacity compressor to a room through a ventilation duct disposed above a ceiling, wherein a surface of the ventilation duct is provided. An air conditioner comprising: a dew condensation sensor provided to detect the dew condensation; and a compression function force control means for controlling the capacity of the compressor based on a detection result of the dew condensation sensor. 3. An air conditioner provided with a variable air volume blower that ventilates an evaporator in a refrigeration cycle, and supplies cold air heat exchanged with the evaporator to a room through a ventilation duct disposed behind the ceiling. , A temperature sensor for detecting the temperature of the air above the ceiling, a humidity sensor for detecting the humidity of the air above the ceiling, an evaporator temperature sensor for detecting the temperature of the evaporator, and detection of each of these sensors An air conditioner comprising: a blower amount controller that controls a blower amount of the blower based on data. 4. An air conditioner provided with a blower having a variable air volume that passes through an evaporator in a refrigeration cycle, and supplies cold air heat exchanged with the evaporator to a room through a ventilation duct disposed behind a ceiling. The air conditioning system according to claim 1, further comprising: a dew condensation sensor provided to detect dew condensation on the surface of the ventilation duct; and a blowing amount control unit configured to control a blowing amount of the blower based on a detection result of the condensation sensor. Machine. 5. The air blower according to claim 3, wherein the blower sucks air behind the ceiling and ventilates the air to the evaporator.
Alternatively, the air conditioner according to claim 4.