JP2002333235A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bring indoor environment into a comfortable state during heating cycle dehumidification operation, in an air conditioner. SOLUTION: An indoor heat exchanger 5 is thermally divided into two sections 5a and 5b. A control device 50 switches to a heating cycle dehumidification operation where and outdoor heat exchanger 3 functions as an evaporator one section 5b of the indoor heat exchanger 5 functions as a condenser, the other section as 5b functions as an evaporator. The capacity of an outdoor supply fan 8 is controlled based on a difference between an indoor temperature Ti and a set indoor temperature Tis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner capable of performing a dehumidifying operation in which room air is heated by condensation heat of a refrigeration cycle.

[0002]

2. Description of the Related Art A conventional air conditioner is disclosed in
-47353, cooling, heating,
For the purpose of enabling the cooling dehumidification operation and the heating dehumidification operation, preventing the indoor temperature rise or temperature decrease during the dehumidification operation, and performing dehumidification while maintaining an arbitrary temperature,
A compressor, an outdoor heat exchanger, a thermally split indoor heat exchanger, and a decompression device for cooling and heating that is disposed between the outdoor heat exchanger and the indoor heat exchanger and performs a depressurizing action during cooling operation and heating operation. A dehumidifying depressurizing device that is disposed between the two divided indoor heat exchangers and performs a depressurizing operation during the dehumidifying operation; and a compressor that is disposed between the compressor and the outdoor heat exchanger and the indoor heat exchanger. It is equipped with an operation switching valve that switches between a cooling cycle that guides the released refrigerant to the outdoor heat exchanger and a heating cycle that guides the refrigerant to the indoor heat exchanger, and performs a cooling operation in which the indoor heat exchanger is an evaporator and the outdoor heat exchanger is a condenser. In the heating operation in which the indoor heat exchanger is a condenser and the outdoor heat exchanger is an evaporator, during the cooling cycle, one of the indoor heat exchangers is an evaporator, the other is a condenser, and the outdoor heat exchanger is a condenser. During the cooling dehumidifying operation and the heating cycle, the indoor heat exchanger One condenser, while the evaporator is that so as to allow switching between the outdoor heat exchanger in the heating Gimi dehumidifying operation of the evaporator.

[0003] As a control method of this air conditioner, four operations of a cooling operation, a heating operation, a cooling dehumidifying operation and a heating dehumidifying operation can be arbitrarily selected, or the indoor temperature is controlled. It is shown that when the temperature is higher than the setting value of the thermostat or the like, the operation is automatically switched to the cooling dehumidification operation, and when the temperature is lower than the setting value, the operation is automatically switched to the heating dehumidification operation.

[0004]

However, in such a conventional air conditioner, it is not disclosed to control the amount of heat absorption or heat release of the outdoor heat exchanger during the heating dehumidifying operation. There has been a problem that sometimes a comfortable indoor environment cannot be achieved or a quick and comfortable indoor environment cannot be achieved. In particular, during the heating dehumidifying operation, if the outdoor air temperature is extremely low, the indoor air cannot be heated to the indoor temperature desired by the user and the indoor temperature decreases, or the un-evaporated refrigerant flows into the compressor and is compressed. There is a problem that the reliability of the machine is reduced. In addition, during the heating dehumidifying operation, when the indoor temperature or the outdoor air temperature is relatively high, the degree of superheat is too large, the refrigerant circulation amount is reduced, and the dehumidifying capacity and the heating capacity are reduced.

An object of the present invention is to provide an air conditioner that can provide a comfortable indoor environment during a heating cycle dehumidifying operation.

Another object of the present invention is to provide an air conditioner capable of maintaining a comfortable indoor environment while maintaining the reliability of a compressor during a heating cycle dehumidifying operation.

Another object of the present invention is to provide an air conditioner capable of maintaining a dehumidifying ability and a heating ability during a heating cycle dehumidifying operation and providing a comfortable indoor environment.

[0008]

Means for Solving the Problems In an air conditioner according to one of the representative inventions of the present invention for achieving the above object,
A compressor, an outdoor heat exchanger, a thermally split indoor heat exchanger, and a cooling / heating device that is disposed between the outdoor heat exchanger and the indoor heat exchanger to perform a depressurizing operation during a cooling operation and a heating operation. A decompression device, a dehumidification decompression device that is disposed between the two divided indoor heat exchangers and performs a decompression operation during a dehumidification operation, and that is disposed between the compressor, the outdoor heat exchanger, and the indoor heat exchanger. A four-way valve that switches between a cooling cycle that guides the refrigerant that has flown out of the compressor to the outdoor heat exchanger and a heating cycle that guides the indoor heat exchanger, a means for detecting the indoor temperature, a means for setting a set indoor temperature, And a control device for controlling the cooling / heating decompression device, the dehumidification decompression device, the four-way valve, and an outdoor blower fan that ventilates the outdoor heat exchanger, wherein the control device performs the indoor heat exchange in the cooling cycle. vessel An evaporator, a cooling operation using the outdoor heat exchanger as a condenser, a heating operation using the indoor heat exchanger in the heating cycle as a condenser, and the outdoor heat exchanger as an evaporator, and the indoor operation in the heating cycle. One of the heat exchangers is a condenser, the other is an evaporator, and has a function of switching to a heating cycle dehumidifying operation in which the outdoor heat exchanger is an evaporator, and has a function of setting a room temperature and an indoor temperature during the heating cycle dehumidifying operation. It has a function of controlling the blowing amount of the outdoor blowing fan based on the difference.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In the embodiments after the second embodiment, illustration and duplication of parts common to the first embodiment will be omitted, and the same reference numerals as those in the first embodiment will be used for the same or equivalent parts. Will be described.

An air conditioner according to a first embodiment of the present invention will be described with reference to FIGS.

First, the configuration of the air conditioner of the present embodiment is shown in FIG.
This will be described with reference to FIG. FIG. 1 is a configuration diagram of an air conditioner according to a first embodiment of the present invention.

In FIG. 1, a refrigeration cycle is arranged between a compressor 1, an outdoor heat exchanger 6, a thermally split indoor heat exchanger 3, and between the outdoor heat exchanger 6 and the indoor heat exchanger 3. The cooling / heating expansion valve 5, which constitutes a cooling / heating decompression device that performs a pressure reducing operation during the cooling operation and the heating operation, between the first indoor heat exchanger 3a and the second indoor heat exchanger 3b. The dehumidifying expansion valve 4, which constitutes a dehumidifying decompression device that performs a depressurizing action during the dehumidifying operation, is disposed between the compressor 1, the outdoor heat exchanger 6, and the indoor heat exchanger 3, and the compressor is disposed. A four-way valve 2 that constitutes an operation switching valve that switches between a cooling cycle that guides the refrigerant discharged from 1 to the outdoor heat exchanger 6 and a heating cycle that guides the refrigerant to the indoor heat exchanger 3 is connected by refrigerant piping. Have been.

The compressor 1 is a variable displacement compressor, and is controlled by a controller 11 by an inverter. The first indoor heat exchanger 3a is formed to have a larger ventilation area and heat exchange area than the second indoor heat exchanger 3b. The outdoor blower fan 8 is installed so that outdoor air is forced to flow through the outdoor heat exchanger 6. The indoor blower fan 7 is installed so as to forcibly ventilate indoor air into the indoor heat exchanger 3. By the operation of the indoor blower fan 7, the indoor air is sucked in parallel into the first indoor heat exchanger 3 a and the second indoor heat exchanger 3 b, and the air discharged therefrom is mixed and blown into the room from the indoor blower fan 7. It has become so. The indoor unit 12 is configured by the indoor heat exchanger 3, the outdoor blower fan 7, the dehumidifying expansion valve 4, and the like.

The remote controller 10 has a setting button for arbitrarily setting a desired operation mode and setting the operation mode to automatic switching, a setting button for setting a desired room temperature, a setting button for setting a desired room humidity, and various other types. And a setting button for setting the operation state of the vehicle.

The indoor air temperature sensor 9 is installed to detect the temperature of the intake air from the indoor heat exchanger 3. The outdoor air temperature sensor 13 is installed to detect the temperature of the intake air from the outdoor heat exchanger 6. The outdoor heat exchanger temperature sensor 14 is installed in contact with the outdoor heat exchanger 6 so as to detect the temperature of the outdoor heat exchanger 6. The indoor heat exchanger temperature first sensor 17 is installed so as to detect the inlet side temperature of the second indoor heat exchanger 3b during the heating cycle dehumidifying operation. The indoor heat exchanger temperature second sensor 18 is installed to detect the outlet side temperature of the second indoor heat exchanger 3b during the heating cycle dehumidification operation. The indoor humidity sensor is installed to detect the intake air humidity of the indoor heat exchanger 3.

The controller 11 includes a remote controller 10, an indoor air temperature sensor 9, an outdoor air temperature sensor 13, an outdoor heat exchanger temperature sensor 14, an indoor heat exchanger temperature first sensor 17,
On the basis of signals from various sensors such as the indoor heat exchanger temperature second sensor 18 and the indoor humidity sensor, the compressor 1, the four-way valve 2, the cooling / heating expansion valve 5, the dehumidification expansion valve 4, the outdoor blower fan 8, and the like are controlled. To control. The control device 11 switches the four-way valve 2 according to the operation mode signal selected by the remote controller 10 and controls the pressure reduction of the cooling / heating expansion valve 5 and the dehumidification expansion valve 4.

Here, the operation when the four operation modes of the air conditioner are arbitrarily selected by the remote controller 10 will be described.

The operation mode selected by the remote controller 10 is as follows:
During the cooling operation, the four-way valve 2 is switched so as to form a cooling cycle in which the refrigerant flowing out of the compressor 1 flows to the outdoor heat exchanger 6, and the cooling / heating expansion valve 5 is throttled, and the dehumidification expansion valve 4 is switched to the other position. Fully open. When the operation mode selected by the remote controller 10 is the heating operation, the four-way valve 2 is switched so as to form a heating cycle in which the refrigerant flowing out of the compressor 1 flows to the indoor heat exchanger 3, and the heating / cooling expansion is performed. The valve 5 is throttled, and the dehumidifying expansion valve 4 is fully opened. When the operation mode selected by the remote controller 10 is the cooling cycle dehumidifying operation, the four-way valve 2 is switched so as to constitute a cooling cycle in which the refrigerant flowing out of the compressor 1 flows to the outdoor heat exchanger 6, and the cooling and heating is performed. The expansion valve for dehumidification 5 is fully opened and the expansion valve for dehumidification 4 is throttled.
When the operation mode selected by the remote controller 10 is the heating cycle dehumidifying operation, the four-way valve 2 is switched so as to constitute a heating cycle in which the refrigerant flowing out of the compressor 1 flows to the indoor heat exchanger 3b. The expansion valve for dehumidification 5 is fully opened and the expansion valve for dehumidification 4 is throttled.

The control operation will be described more specifically.
When the user selects the cooling operation mode, the control device 1
1 receives the signal of the cooling operation mode from the remote controller 10, fully opens the expansion valve 4 for dehumidification, transmits the signal to throttle the expansion valve 5 for cooling and heating, and sets the outdoor heat exchanger 6 to the condenser and the indoor heat exchanger. 3 acts as an evaporator. Thereby, the air cooled by the indoor heat exchanger 3 is blown into the room, and the cooling operation is performed.

When the user selects the heating operation mode, the control device 11 receives the signal of the heating operation mode from the remote controller 10, opens the dehumidification expansion valve 4 fully, and throttles the cooling / heating expansion valve 5. To make the outdoor heat exchanger 6 function as an evaporator and the indoor heat exchanger 3 as a condenser. Thereby, the air heated by the indoor heat exchanger 3 is blown into the room, and the heating operation is performed.

When the user selects the cooling cycle dehumidifying operation mode, the control device 11 receives a signal of the cooling cycle dehumidifying operation mode from the remote controller 10 and the refrigerant having exited the compressor 1 is supplied to the outdoor heat exchanger 6. The four-way valve 2 is switched so as to flow through the air-conditioner, the cooling / heating expansion valve 5 is fully opened, and the dehumidifying expansion valve 4 is controlled to be throttled. Thereby, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 passes from the four-way valve 2 through the outdoor heat exchanger 6 and the fully-opened cooling / heating expansion valve 5, and passes through the indoor blower fan 7 in the second indoor heat exchanger 3b. The heat is condensed by dissipating heat to the air blown by the air, decompressed by the dehumidifying expansion valve 4, expanded to a temperature equal to or lower than the dew point temperature of the indoor air, and
At a, it absorbs heat from the air blown by the indoor blower fan 7 and evaporates, passes through the four-way valve 2 and returns to the compressor 1 again. At this time, the air heated by the second indoor heat exchanger 3b and the air cooled and dehumidified by the first indoor heat exchanger 3a are mixed and sent to the room, and the cooling cycle dehumidifying operation is performed.

When the user selects the heating cycle dehumidifying operation mode, the control device 11 receives a signal of the heating cycle dehumidifying operation mode from the remote controller 10 and the refrigerant having exited from the compressor 1 is supplied to the indoor heat exchanger 3. The four-way valve 2 is switched so that the air flows through the expansion valve 4 for dehumidification and the expansion valve 5 for cooling and heating.
Is fully opened. As a result, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 passes through the four-way valve 2 and
The indoor heat exchanger 3a radiates heat to the air blown by the indoor blower fan 7, condenses, decompresses the air by the expansion valve 4 for dehumidification, and absorbs heat from the air blown by the indoor blower fan 7 in the second indoor heat exchanger 3b. And passes through the four-way valve 2 through the fully-opened cooling / heating expansion valve 5 and the outdoor heat exchanger 6, and the compressor 1 again.
Return to At this time, the air heated by the first indoor heat exchanger 3a and the air dehumidified by cooling and dehumidification by the second indoor heat exchanger 3b are mixed and blown into the room, and the heating cycle dehumidifying operation is performed.

As described above, the operation modes of cooling, heating, cooling cycle dehumidification, and heating cycle dehumidification can be arbitrarily selected according to the operation mode set by the user. Can be

Next, the operation when the four operation modes of the air conditioner are automatically selected by the remote controller 10 will be described.

When performing automatic driving, the user:
An automatic operation mode button on the remote controller 10 is selected. As a result, the compressor 1 is driven to circulate the refrigerant in the refrigeration cycle, the outdoor blower fan 7 is driven to drive the outdoor air to the outdoor heat exchanger 3, and the indoor blower fan 8 is driven to drive the indoor air. Is passed through the indoor heat exchanger 5, and the air conditioner is operated. Then, a desired room temperature is set by pressing the room temperature setting button of the remote controller 10. In this state,
The indoor air temperature sensor 9 detects the indoor temperature. The cooling operation, the heating operation, the cooling cycle dehumidifying operation, and the heating cycle dehumidifying operation are automatically switched based on the difference between the set room temperature and the room temperature. Thereby, the indoor temperature can be reached in a short time to the set indoor temperature desired by the user, and a comfortable indoor environment can be achieved.

The specific operation of the heating cycle dehumidifying operation in the above-described air conditioner will be described with reference to FIGS. FIG. 2 is an operation flowchart of a heating cycle dehumidifying operation of the air conditioner of the first embodiment of the present invention, FIG. 3 is a temperature characteristic diagram of an outdoor fan change amount in the air conditioner,
FIG. 4 is a temperature characteristic diagram of an outdoor fan change amount in a modification of the air conditioner.

The user selects the heating cycle dehumidifying operation mode button on the remote controller 10 to start the heating cycle dehumidifying operation (step 101). Thereby, the compressor 1 is driven, the four-way valve 2 moves to the heating cycle side, the refrigerant circulates through the refrigeration cycle, and the outdoor blower fan 7 is driven to ventilate the outdoor air to the outdoor heat exchanger 3. At the same time, the indoor blower fan 8 is driven to ventilate the indoor air into the indoor heat exchanger 5, and the above-described heating cycle dehumidifying operation is performed. Then, the user presses the room temperature setting button of the remote controller 10 to set a desired set room temperature Tis (step 102). When the user selects the automatic operation mode, the heating cycle dehumidifying operation starts when the condition for performing the heating cycle dehumidifying operation is satisfied, and the set room temperature Tis is set in advance.

The room temperature Ti is detected by the room temperature sensor 9 and the detected value is sent to the controller 11 (step 10).
3). Next, the room temperature Ti is set to the set room temperature Tis.
It is determined whether it is lower (Ti <Tis) (step 104). In this determination, when the room temperature Ti is lower than the set room temperature Tis, the rotation speed of the outdoor blower fan 8 is increased as shown in FIG. 3 (step 105), and the process returns to step 102. This operation of increasing the rotation speed of the outdoor blower fan 8 is continued until the room temperature Ti becomes equal to or higher than the set room temperature Tis.

More specifically, this operation will be described. For example, when the heating cycle dehumidifying operation is started at a user-set room temperature Tis of 25 ° C. and a room temperature Ti of 20 ° C., the room temperature Ti is smaller than the set room temperature Tis. Therefore, the control device 11 increases the rotation speed of the outdoor blower fan 8 based on FIG. That is, the set room temperature Tis and the room temperature T
The rotational speed of the outdoor blower fan 8 is increased in proportion to the difference Ti-Ti from i. Due to the increase in the rotation speed of the outdoor blower fan 8, the amount of air passing through the outdoor heat exchanger 6 increases, and the amount of heat absorbed by the outdoor heat exchanger 6 increases. This increased heat absorption adds to the heat radiation from the first indoor heat exchanger 3a. That is, since the amount of heat radiation in the first indoor heat exchanger 3a increases, the temperature of the air blown out from the indoor unit 12 increases, and the indoor temperature increases.

If it is determined in step 104 that the indoor temperature Ti is equal to or higher than the set indoor temperature Tis, the rotational speed of the outdoor blower fan 8 is reduced (step 106).
Return to step 102. This operation of reducing the rotation speed of the outdoor blower fan 8 is continued until the room temperature Ti becomes lower than the set room temperature Tis.

This operation will be described in more detail. For example, when the heating cycle dehumidifying operation is started at a room temperature Ti set by the user of 25 ° C. and room temperature Ti of 30 ° C. (or a state where the room temperature Ti is 30 ° C.) If the setting of the set indoor temperature Tis is changed to 25 ° C. during the heating cycle dehumidifying operation of the air conditioner, the indoor temperature Ti <the set indoor temperature Tis
Therefore, the control device 11 reduces the rotation speed of the outdoor blower fan 8 based on FIG. That is, the set room temperature Ti
The number of rotations of the outdoor blower fan 8 is reduced in proportion to the magnitude of the difference Tis-Ti between s and the indoor temperature Ti. Due to the deceleration of the rotation speed of the outdoor blower fan 8, the amount of air passing through the outdoor heat exchanger 6 decreases, and the amount of heat absorbed decreases, and the amount of heat released from the first indoor heat exchanger 3a by the reduced amount of heat absorbed. Decrease. Then, since the amount of heat radiation in the first indoor heat exchanger 3a decreases, the temperature of the air blown out from the indoor unit 12 decreases, and the indoor temperature decreases.

In this embodiment, in the heating cycle dehumidifying operation, even if the room temperature Ti is different from the set room temperature Tis, the blown air temperature can be controlled by increasing or decreasing the amount of air blown by the outdoor blower fan 8, so that the room temperature Ti can be controlled. Can be reached in a short time to the set indoor temperature Tis desired by the user, and a comfortable indoor environment can be achieved. If the control of the decompression amount of the dehumidifying expansion valve 4 is not performed by increasing or decreasing the amount of air blown by the outdoor blower fan 8, the dehumidifying expansion valve 4 does not need to be of a variable decompression amount type, and is inexpensive. A dehumidifying expansion valve 4 can be used.

Further, in this embodiment, as shown in FIG. 3, the relationship between the increase and decrease of the number of revolutions of the outdoor blower fan 8 based on the difference between the indoor set temperature Tis and the indoor temperature Ti is a proportional relationship.
As shown in FIG. 4, the number of revolutions of the outdoor blower fan 8 may be determined stepwise. In this case, the capacity of the control memory for controlling the rotation speed of the outdoor blower fan 8 can be reduced.

In this embodiment, the case where the outdoor blower fan 8 is operated has been described. However, in the case where the indoor temperature is high where the dryness is high, it is preferable that the outdoor fan be stopped or operated at an extremely low speed. By stopping or operating the outdoor fan at an extremely low speed, the dryness of the refrigerant in the outdoor heat exchanger 6 is reduced, so that a large amount of the refrigerant is present in the outdoor heat exchanger 6 and the excess in the refrigeration cycle. The refrigerant is stored, and the pressure on the high pressure side (compressor discharge to the first indoor heat exchanger 3a) of the refrigeration cycle can be reduced, and the electric input to the air conditioner can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 5 is an operation flowchart of a heating cycle dehumidifying operation of the air conditioner according to the second embodiment of the present invention,
FIG. 6 is a temperature characteristic diagram of the pressure reduction amount of the cooling / heating expansion valve during the heating cycle dehumidifying operation of the air conditioner. This embodiment is different from the first embodiment as described below, and the other points are the same as the first embodiment, and the illustration corresponding to FIG. 1 and the description thereof are omitted.

In the present embodiment, the controller 11 determines the outdoor air temperature To detected by the outdoor air temperature sensor 13 and the outdoor heat exchanger temperature Toh detected by the outdoor heat exchanger temperature sensor 14 during the heating cycle dehumidifying operation. Then, as described below, the variable pressure reducing air-conditioning expansion valve 5 is controlled.

The user selects the heating cycle dehumidifying operation mode button on the remote controller 10 to start the heating cycle dehumidifying operation (step 201). Thereby, the compressor 1 is driven, the four-way valve 2 moves to the heating cycle side, the refrigerant circulates through the refrigeration cycle, and the outdoor blower fan 7 is driven to ventilate the outdoor air to the outdoor heat exchanger 3. At the same time, the indoor blower fan 8 is driven to ventilate the indoor air into the indoor heat exchanger 5, and the above-described heating cycle dehumidifying operation is performed.

Then, the outdoor air temperature To is detected by the outdoor air temperature sensor 13 and the detected value is sent to the control device 11 (step 202), and the outdoor heat exchanger temperature sensor 1 is detected.
4, the outdoor heat exchanger temperature Toh is detected, and the detected value is sent to the control device 11 (step 203). Next, it is determined whether or not the outdoor air temperature To is higher than the outdoor heat exchanger temperature Toh (whether To> Toh) (step 20).
4). In this determination, when the outdoor air temperature To is higher than the outdoor heat exchanger temperature Toh, as shown in FIG. 6, the pressure reduction amount (ie, the throttle amount) of the cooling / heating expansion valve 5 is increased (step 205). Return to 202. The operation of increasing the decompression amount of the cooling / heating expansion valve 5 is continued until the outdoor air temperature To falls below the outdoor heat exchanger temperature Toh.

This operation will be described more specifically. For example, the outdoor air temperature To is 0 ° C., and the outdoor heat exchanger temperature Toh
When the heating cycle dehumidifying operation is started at 5 ° C., since the outdoor air temperature To> the outdoor heat exchanger temperature Toh, the control device 11 reduces the amount of pressure reduction of the cooling / heating expansion valve 5 based on FIG. In other words, the difference between the outdoor air temperature To and the outdoor heat exchanger temperature Toh is increased in proportion to the outdoor air temperature To minus the outdoor heat exchanger temperature Toh, and the amount of pressure reduction of the cooling / heating expansion valve 5 is increased. Since the refrigerant temperature (ie, outdoor heat exchanger temperature) Toh of the outdoor heat exchanger 6 becomes lower than the outdoor air temperature To due to the increase in the amount of pressure reduction of the cooling / heating expansion valve 5, the refrigerant flowing into the outdoor heat exchanger 6 Absorbs heat from the air blown by the outdoor blower fan 8 and evaporates.

If the outdoor air temperature To is equal to or lower than the outdoor heat exchanger temperature Toh in the determination in step 204 described above,
As shown in FIG. 6, the pressure reduction amount of the cooling / heating expansion valve 5 is reduced (step 206), and the process returns to step 202. The operation for reducing the pressure reduction amount of the cooling / heating expansion valve 5 is referred to as an outdoor air temperature T.
It continues until o falls below the outdoor heat exchanger temperature Toh.

As described above, according to the present embodiment, the heat is absorbed in the outdoor heat exchanger 6 even at a low outdoor temperature, so that the heat absorption is secured, and the heat of condensation in the first indoor heat exchanger 3a (that is, the indoor heat exchange). (The amount of heating to air) is ensured, and a decrease in the temperature of the air blown indoors can be prevented. In addition, since the refrigerant is evaporated also in the outdoor heat exchanger 6, the amount of the refrigerant returning to the compressor 1 can be reduced, and the reliability of the compressor 1 can be improved.

Next, a third embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 7 is an operation flowchart of a heating cycle dehumidifying operation of the air conditioner according to the third embodiment of the present invention,
FIG. 8 is a Mollier chart during a heating cycle dehumidifying operation of the air conditioner. This embodiment is different from the first embodiment as described below, and the other points are the same as the first embodiment, and the illustration corresponding to FIG. 1 and the description thereof are omitted.

In this embodiment, during the heating cycle dehumidifying operation, the controller 11 controls the outdoor air temperature To detected by the outdoor air temperature sensor 13 and the second indoor heat exchanger detected by the first indoor heat exchanger temperature sensor 17. Based on the inlet temperature Tei and the second indoor heat exchanger outlet temperature Teo detected by the indoor heat exchanger temperature second sensor 18, the variable pressure reducing air-conditioning expansion valve 5 is controlled as described below. Expansion valve for dehumidification 4
Has an on-off valve structure that opens and closes a passage with a valve element. When the valve element is closed, a minute flow path is formed between the first indoor heat exchanger 3a and the second indoor heat exchanger 3b. It is configured to perform a pressure reducing action. Here, since the second indoor heat exchanger 3b is an evaporator during the heating / dehumidification cycle operation, the second indoor heat exchanger outlet temperature Teo detected by the second indoor heat exchanger temperature sensor 18 and the indoor heat exchanger temperature Difference Teo from second indoor heat exchanger inlet temperature Tei detected by first sensor 17
Since −Tei is the degree of superheat SH in the second indoor heat exchanger 3b, both sensors 17 and 18 constitute the degree of superheat detection of the second indoor heat exchanger 3b.

The user selects the heating cycle dehumidifying operation mode button on the remote controller 10 to start the heating cycle dehumidifying operation (step 301). Thereby, the compressor 1 is driven, the four-way valve 2 moves to the heating cycle side, the refrigerant circulates through the refrigeration cycle, and the outdoor blower fan 7 is driven to ventilate the outdoor air to the outdoor heat exchanger 3. At the same time, the indoor blower fan 8 is driven to ventilate the indoor air into the indoor heat exchanger 5, and the above-described heating cycle dehumidifying operation is performed.

Then, the outdoor air temperature To is detected by the outdoor air temperature sensor 13 and the detected value is sent to the controller 11 (step 302), and the second indoor heat exchanger inlet is detected by the first indoor heat exchanger temperature sensor 17. The temperature Tei is detected and the detected value is sent to the control device 11 (step 303). Further, the second indoor heat exchanger outlet temperature Teo is detected by the second indoor heat exchanger temperature sensor 18, and the detected value is controlled.
(Step 304). The superheat degree SH is calculated by calculating the difference between the second indoor heat exchanger outlet temperature Teo and the second indoor heat exchanger inlet temperature Tei (step 305). Next, the superheat degree SH is set to a predetermined set superheat degree SH.
s is determined (SH> SHs or not)
(Step 306). In this determination, if the superheat degree SH is larger than the set superheat degree SHs, the process proceeds to step 307. ), And return to step 302.

In step 307, it is determined whether or not the second indoor heat exchanger outlet temperature Teo is higher than the outdoor air temperature To (Te).
o> To) (step 307). If it is determined that the outlet temperature Teo of the second indoor heat exchanger is lower than the outdoor air temperature To, the process proceeds to step 309. If the temperature Teo is higher than the outdoor air temperature To, the amount of pressure reduction (ie, the amount of throttle) of the cooling / heating expansion valve 5 is reduced. (Step 308), and the process returns to Step 302. The operation of minimizing the pressure reduction amount of the cooling / heating expansion valve 5 (fully opening the valve) is continued until the second indoor heat exchanger outlet temperature Teo falls to or below the outdoor air temperature To.

This operation will be described more specifically. For example, the indoor heat exchanger temperature Te is 10 ° C., the second indoor heat exchanger outlet temperature Teo is 20 ° C., the set superheat degree SHs is 3 ° C., and the outdoor air temperature To is When the heating cycle dehumidifying operation is started at 0 ° C., since SH> SHs and To <Teo, the controller 11 minimizes the pressure reduction amount of the cooling / heating expansion valve 5. Thereby, the refrigerant superheated in the second indoor heat exchanger 3b flows into the outdoor heat exchanger 6 without being decompressed by the cooling / heating expansion valve 5, and radiates heat to the outdoor air blown by the outdoor blower fan 8 to overheat. The temperature decreases and returns to the compressor 1 again through the four-way valve 2. FIG. 8 shows the above process in a Mollier diagram.

As described above, even if the refrigerant is significantly overheated in the second indoor heat exchanger 3b, the degree of superheat of the refrigerant returning to the compressor 1 is reduced by operating the outdoor heat exchanger 6 as a refrigerant cooler. Since the size of the refrigerant can be reduced, it is possible to prevent the refrigerant flowing into the compressor from having an excessive degree of superheat, thereby reducing the amount of circulating refrigerant, and preventing the dehumidifying ability and the superheating ability from decreasing. Further, the temperature rise of the compressor 1 due to the excessive degree of superheat can be suppressed, so that the reliability of the compressor can be improved.

In each of the embodiments described above, it is described that they operate independently. However, by operating these embodiments in combination, more appropriate control can be performed.

[0050]

According to the present invention, an air conditioner which can provide a comfortable indoor environment during a heating cycle dehumidifying operation can be obtained.

Further, according to the present invention, it is possible to obtain an air conditioner capable of maintaining a comfortable indoor environment while maintaining the reliability of the compressor during the heating cycle dehumidifying operation.

Further, according to the present invention, it is possible to obtain an air conditioner capable of maintaining a comfortable indoor environment while maintaining the dehumidifying ability and the heating ability during the heating cycle dehumidifying operation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is an operation flowchart of a heating cycle dehumidifying operation of the air conditioner.

FIG. 3 is a temperature characteristic diagram of an outdoor fan change amount in the air conditioner.

FIG. 4 is a temperature characteristic diagram of an outdoor fan change amount in a modified example of the air conditioner.

FIG. 5 is an operation flowchart of a heating cycle dehumidifying operation of the air conditioner according to the second embodiment of the present invention.

FIG. 6 is a temperature characteristic diagram of a pressure reduction amount of a cooling / heating expansion valve during a heating cycle dehumidifying operation of the air conditioner.

FIG. 7 is an operation flowchart of a heating cycle dehumidifying operation of the air conditioner according to the third embodiment of the present invention.

FIG. 8 is a Mollier chart during a heating cycle dehumidifying operation of the air conditioner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four-way valve, 3 ... Indoor heat exchanger, 3a ... 1st indoor heat exchanger, 3a ... 2nd indoor heat exchanger, 4 ... Dehumidification expansion valve (dehumidification decompression device), 5 ... Expansion valve for cooling and heating (pressure reducing device for cooling and heating), 6 outdoor heat exchanger, 7 indoor fan, 8 outdoor fan, 9 indoor air temperature sensor, 1
0: remote control, 11: control device, 12: indoor unit, 13
... outdoor air temperature sensor, 14 ... outdoor heat exchanger temperature sensor, 17 ... indoor heat exchanger temperature first sensor, 18 ... indoor heat exchanger temperature second sensor.

Continued on the front page (72) Inventor Ryoichi Takato 502 Kandachicho, Tsuchiura-city, Ibaraki Pref. F-term in Machine Research Laboratory, Hitachi, Ltd. (Reference) 3L060 AA06 AA07 CC02 CC07 DD07 EE04 EE05 EE06 EE09

Claims (7)

[Claims] 1. A compressor, an outdoor heat exchanger, a thermally split indoor heat exchanger, and a pressure reducer disposed between the outdoor heat exchanger and the indoor heat exchanger during a cooling operation and a heating operation. A decompression device for cooling and heating that performs an operation, a decompression device for dehumidification that is disposed between the two divided indoor heat exchangers and that performs a decompression operation during a dehumidification operation, the compressor, the outdoor heat exchanger, and the indoor heat exchanger A four-way valve that switches between a cooling cycle that guides the refrigerant discharged from the compressor to the outdoor heat exchanger and a heating cycle that guides the refrigerant to the indoor heat exchanger, means for detecting the indoor temperature, and a set indoor temperature. And a control device that controls the cooling / heating decompression device, the dehumidification decompression device, the four-way valve, and an outdoor blower fan that ventilates the outdoor heat exchanger. The control device includes the cooling cycle. Said in An indoor heat exchanger as an evaporator, a cooling operation using the outdoor heat exchanger as a condenser, and a heating operation using the indoor heat exchanger as a condenser and the outdoor heat exchanger as an evaporator in the heating cycle,
One of the indoor heat exchangers in the heating cycle has a function of switching to a heating cycle dehumidifying operation in which one of the indoor heat exchangers is a condenser, the other is an evaporator, and the outdoor heat exchanger is an evaporator. An air conditioner having a function of controlling a blowing amount of the outdoor blowing fan based on a difference between a temperature and a room temperature. 2. The air conditioning system according to claim 1, wherein, during the heating cycle dehumidifying operation, the amount of air blown by the outdoor blower fan is increased when the room temperature is lower than a set room temperature, and when the room temperature is higher than the set room temperature. An air conditioner characterized by reducing the amount of air blown by an outdoor blower fan. 3. The air conditioner according to claim 1, wherein, during the heating cycle dehumidifying operation, the outdoor blower fan is stopped or is rotated at an extremely low speed when the indoor temperature at which the dryness is high. 4. A compressor, an outdoor heat exchanger, a thermally split indoor heat exchanger, and a decompressor disposed between the outdoor heat exchanger and the indoor heat exchanger during a cooling operation and a heating operation. A decompression device for cooling and heating that performs an operation, a decompression device for dehumidification that is disposed between the two divided indoor heat exchangers and that performs a decompression operation during a dehumidification operation, the compressor, the outdoor heat exchanger, and the indoor heat exchanger A four-way valve that switches between a cooling cycle that guides refrigerant discharged from the compressor to the outdoor heat exchanger and a heating cycle that guides the refrigerant to the indoor heat exchanger, means for detecting outdoor air temperature, Means for detecting the temperature of the heat exchanger, and a control device for controlling the decompression device for cooling and heating, the decompression device for dehumidification, and the four-way valve, the control device, the indoor heat exchanger in the cooling cycle Evaporator, chamber A cooling operation using an outdoor heat exchanger as a condenser, a heating operation using the indoor heat exchanger in the heating cycle as a condenser, and the outdoor heat exchanger as an evaporator,
One of the indoor heat exchangers in the heating cycle has a function of switching to a heating cycle dehumidifying operation in which one of the indoor heat exchangers is a condenser, the other is an evaporator, and the outdoor heat exchanger is an evaporator. An air conditioner having a function of controlling a pressure reduction amount of the cooling / heating decompression device so that an outdoor air temperature is lower than an exchanger temperature. 5. The air conditioner according to claim 4, wherein during the heating cycle dehumidifying operation, when the outdoor air temperature is higher than the outdoor heat exchanger temperature, the pressure reduction amount of the cooling / heating decompression device is increased. 6. A compressor, an outdoor heat exchanger, a thermally split indoor heat exchanger, and a pressure reducer disposed between the outdoor heat exchanger and the indoor heat exchanger during a cooling operation and a heating operation. A decompression device for cooling and heating that performs an operation, a decompression device for dehumidification that is disposed between the two divided indoor heat exchangers and that performs a decompression operation during a dehumidification operation, the compressor, the outdoor heat exchanger, and the indoor heat exchanger A four-way valve that switches between a cooling cycle that guides the refrigerant discharged from the compressor to the outdoor heat exchanger and a heating cycle that guides the refrigerant to the indoor heat exchanger, and detects the degree of superheat of the indoor heat exchanger. Superheat degree detecting means, and a control device for controlling the decompression device for cooling and heating, the decompression device for dehumidification, and the four-way valve, wherein the control device evaporates the indoor heat exchanger in the cooling cycle, Condensing outdoor heat exchanger A cooling operation as a heat exchanger, a heating operation with the indoor heat exchanger in the heating cycle as a condenser, and the outdoor heat exchanger as an evaporator,
One of the indoor heat exchangers in the heating cycle is a condenser, the other is an evaporator, and has a function of switching to a heating cycle dehumidifying operation in which the outdoor heat exchanger is an evaporator. An air conditioner having a function of controlling the outdoor heat exchanger to cool a superheated refrigerant when the heat exchanger is in an overheated state. 7. A temperature sensor according to claim 6, wherein a temperature sensor is provided on each of the other inlet side and the outlet side of said indoor heat exchanger which becomes an evaporator during said heating cycle dehumidifying operation, and a temperature difference between said two temperature sensors causes an overheating state. An air conditioner characterized by detecting and controlling the pressure reduction amount of the cooling / heating decompression device to a minimum when the air conditioner is overheated.