JPH11182994A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a continuous heating operation during a defrosting operation in a heat pump operation without lowering the heating capacity. SOLUTION: An air conditioner is provided with a heat pump type refrigerating cycle wherein a compressor 1, a four-way valve 2, an indoor heat exchanger 10, a motor-driven expansion valve 5, and an outdoor heat exchanger 3 are connected by a refrigerant circuit. A refrigerant heating circuit having a refrigerant heater 4 is provided by connecting a space between the motor-driven expansion valve 5 and the outdoor heat exchanger 3 and the suction side of the compressor 1, and a defrosting circuit 9 is provided by connecting the discharge side of the compressor 1 and a space between the indoor heat exchanger 3 and the four-way valve 2. In a defrosting operation of a heat pump operation, a refrigerant heated by the refrigerant heater 4 passes the compressor 1, and branched into a flow flowing through the indoor heat exchanger 10 and a flow flowing from the defrosting circuit 9 to the outdoor heat exchanger 3, the inside of a room is heated by the refrigerant flowing through the indoor heat exchanger 10, and defrosting of the outdoor heat exchanger 3 is carried out simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an air conditioner capable of switching between a refrigerant heating operation and a heat pump operation during a heating operation.

[0002]

2. Description of the Related Art Conventionally, as an air conditioner mainly for cold regions, a type capable of switching between a refrigerant heating operation and a heat pump operation during a heating operation has been proposed. As such an air conditioner, for example, as described in Japanese Patent Application No. 2-93238, a refrigerant heating operation is performed based on a difference between a set temperature and an indoor temperature and a difference between a set temperature and an outside air temperature. And switching between heat pump operation and heat pump operation are known.

However, in this air conditioner, no consideration is given to defrosting of the outdoor heat exchanger during operation of the heat pump. Therefore, it is conceivable to prevent frost formation itself by setting the reference temperature for switching between the heat pump operation and the refrigerant heating operation to a level that does not cause frost during the heat pump operation. However, in this case, even if the feeling of high heating can be maintained, the temperature range in which the heat pump operation with higher energy efficiency is performed is narrower than in the refrigerant heating operation, and there is a problem in running cost.

In addition, in the system in which the operation is switched to the refrigerant heating operation at the time of frosting regardless of the outside air temperature, the switching between the refrigerant heating operation and the heat pump operation is frequently performed. Is reduced.

[0005] Therefore, an air conditioner that performs defrosting by hot gas from a compressor during a heat pump operation as shown in FIG. 5 has also been proposed. In FIG. 5, this air conditioner includes a heat pump type refrigeration cycle in which a compressor 1, a four-way valve 2, an indoor heat exchanger 10, an expansion valve 5, and an outdoor heat exchanger 3 are connected by a refrigerant circuit. Further, in this refrigeration cycle, the refrigerant heater 4 is connected between the expansion valve 5 and the outdoor heat exchanger 3 and the suction side of the compressor 1.
Is provided. Further, in this refrigeration cycle, a connection between the discharge side of the compressor 1 and the expansion valve 5 side of the outdoor heat exchanger 3 is provided with a defrosting circuit 19 having a two-way valve 19a. In the drawings, reference numerals 7 and 8 indicate two-way valves, and reference numeral 11 indicates a check valve.

In this air conditioner, the two-way valves 17 and 19a are closed and the two-way valve 8 is opened in FIG. 5 to perform a refrigerant heating operation in a refrigerant circulation path as shown by a dashed arrow. By closing the two-way valves 8 and 19a and opening the two-way valve 7, the heat pump operation is performed in the refrigerant circulation path as shown by the solid arrow.

This air conditioner is shown in FIG.
By closing the two-way valve 8 and opening the two-way valves 7, 19a,
In the refrigerant circulation path as shown by solid and dashed line arrows,
It is configured to perform defrosting with hot gas (high-temperature and high-pressure gas refrigerant) during heat pump operation. That is, the outdoor heat exchanger 3 is connected to the indoor heat exchanger 10 by the expansion valve 5.
In addition to the liquid refrigerant (see the solid line arrow) sent through the compressor, the hot gas is sent from the compressor 1 through the defrost circuit 19 (see the dashed line arrow) to raise the temperature of the outdoor heat exchanger 3. , Defrosting is performed.

However, in this air conditioner, a part of the hot gas from the compressor 1 is sent to the outdoor heat exchanger 3 through the defrosting circuit 19 at the time of defrosting. Absent.

[0009]

As described above, in the conventional air conditioner, the defrosting operation is performed at the time of frost formation during the heat pump operation, and the continuous heating operation is performed without lowering the heating capacity. Is difficult to do.

The present invention has been made in view of the above points, and in an air conditioner capable of switching between a refrigerant heating operation and a heat pump operation during a heating operation, the present invention relates to a defrosting operation during a heat pump operation. It is another object of the present invention to provide an air conditioner capable of performing a continuous heating operation without lowering the heating capacity.

[0011]

The first means is a compressor,
A heat pump type refrigeration cycle in which a four-way valve, an indoor heat exchanger, an expansion mechanism, and an outdoor heat exchanger are connected by a refrigerant circuit, and between the expansion mechanism and the outdoor heat exchanger in the refrigeration cycle, Connect between the suction side,
A refrigerant heating circuit having a refrigerant heater; a discharge side of a compressor in the refrigeration cycle; and a defrosting circuit connecting the outdoor heat exchanger and the four-way valve. When performing the defrosting of the outdoor heat exchanger at the time, the refrigerant heated by the refrigerant heater passes through the compressor, and then flows through the indoor heat exchanger and the outdoor and the defrosting circuit. And a flow passing through a heat exchanger, wherein the flows of these branched refrigerants are joined at an inlet of the refrigerant heating circuit and are heated again by the refrigerant heater. It is an air conditioner.

According to the first means, when defrosting the outdoor heat exchanger during the heat pump operation of the refrigeration cycle, the defrost of the outdoor heat exchanger is performed by using the refrigerant heated by the refrigerant heater. At the same time, heating by the indoor heat exchanger can be performed.

The second means is the first means, further comprising a room temperature detector for detecting an indoor temperature and an outdoor temperature detector for detecting an outside air temperature, wherein the set temperature and the room detected by the room temperature detector are detected. Switching between the refrigerant heating operation and the heat pump operation during the heating operation is performed based on the difference from the temperature and the outside air temperature detected by the outside air temperature detector.

A third means is the second means, further comprising an indoor unit including the indoor heat exchanger, and an outdoor unit including the outdoor heat exchanger, wherein the indoor unit includes the room temperature detector, An indoor control unit that determines an operation code based on the room temperature detected by the room temperature detector and the input set temperature, and the outdoor unit includes the outdoor air temperature detector and an outdoor control unit. The outdoor control unit, based on the operation code transmitted from the indoor control unit of the indoor unit and the outside air temperature detected by the outside air temperature detector, the refrigerant heating operation and the heat pump operation during the heating operation The switching is determined.

[0015] According to the third means, in the second means, the indoor control unit of the indoor unit communicates with the outdoor control unit of the outdoor unit.
Since it is sufficient to transmit only the operation code as compared with the case where it is necessary to transmit the signal of the set temperature and the signal of the room temperature, it is possible to reduce the communication load between the two control units.

A fourth means is the second or third means, wherein the threshold value of the outside air temperature as a reference for switching between the refrigerant heating operation and the heat pump operation is a threshold value when switching from the refrigerant heating operation to the heat pump operation. The value is set higher than the threshold value when switching from the heat pump operation to the refrigerant heating operation.

According to the fourth means, in the second or third means, the frequency of switching between the refrigerant heating operation and the heat pump operation with respect to the change in the outside air temperature is reduced, so that the heating capacity accompanying the switching is reduced. It is possible to suppress the decrease and prevent the decrease in the room temperature.

A fifth means is the fourth means, wherein the setting of the threshold value of the outside air temperature can be changed.

According to the fifth means, in the fourth means, the switching between the refrigerant heating operation based on the outside air temperature and the heat pump operation is optimally performed in accordance with the installation conditions and use conditions of the air conditioner. It can be adjusted.

A sixth means is that, in any one of the first to fifth means, if the fuel for heating the refrigerant heater runs out of fuel during the refrigerant heating operation, the operation is stopped, It is configured to perform a fuel shortage display.

[0021] According to the sixth means, compared to any of the first to fifth means, when the fuel is exhausted, the operation is automatically switched to the heat pump operation and the operation is continued. It is not necessary to give a user who is expecting a discomfort due to a decrease in the heating capacity due to the switching to the heat pump operation.

[0022]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 4 are views showing an embodiment of an air conditioner according to the present invention. FIG.
In the embodiments of the present invention shown in FIG. 4 to FIG. 4, the same components as those in the conventional example shown in FIG.

In FIG. 1, the air conditioner of the present embodiment has a compressor 1, a four-way valve 2, an indoor heat exchanger 10, an electric expansion valve (expansion mechanism) 5, and an outdoor heat exchanger 3 connected by a refrigerant circuit. Equipped with a heat pump refrigeration cycle.
In this refrigeration cycle, a refrigerant having a two-way valve 8 and a combustion-type refrigerant heater 4 is connected between the electric expansion valve 5 and the outdoor heat exchanger 3 and the suction side of the compressor 1. A heating circuit is provided.

Further, in this refrigerating cycle, the discharge side of the compressor 1 is connected to the outdoor heat exchanger 3 and the four-way valve 2 to form a defrosting circuit having a two-way valve 9a and a capillary tube 9b. 9 are provided. Note that reference numeral 6 in FIG.
Shown at and 7 are two-way valves.

Next, FIG. 2 shows an outline of a control system in the air conditioner of the present embodiment. In FIG. 2, the air conditioner includes an indoor unit A including the indoor heat exchanger 10 and an outdoor unit B including the outdoor heat exchanger 3 and others. Then, the indoor unit A includes an indoor control unit a1.
And a room temperature detector a2 for detecting the room temperature Ta and inputting it to the room controller a1. The indoor controller a1 has a set temperature T by means of a remote controller or the like.
s is entered.

On the other hand, the outdoor unit B has an outdoor control section b1 and an outside air temperature detector b2 for detecting the outside air temperature T0 and inputting it to the outdoor control section b1. Also, the indoor unit B is
It has a fuel sensor b3 to be described later and an out-of-fuel indicator b4.

In this air conditioner, in FIG. 4, the two-way valves 8 and 9a are closed and the two-way valves 6 and 7 are opened to perform a heat pump operation in a refrigerant circulation path as indicated by solid arrows. At the same time, the two-way valves 6, 7, 9a are closed and the two-way valve 8 is opened, so that the refrigerant heating operation is performed in the refrigerant circulation path as shown by the dashed arrow.

That is, during the operation of the heat pump indicated by the solid arrow in FIG. 4, the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the indoor heat exchanger 10 and exchanges heat with the indoor air to change the indoor air. Heat up. Thereafter, the refrigerant passes through the electric expansion valve 5 and becomes low-temperature and low-pressure, enters the outdoor heat exchanger 3 through the two-way valve 7, where it exchanges heat with outside air and absorbs heat.
It is sucked into the compressor 1 again.

During the refrigerant heating operation, the compressor 1 is operated by opening the two-way valve 6 and closing the two-way valves 7 and 8 before starting the operation, and the refrigerant accumulated in the outdoor heat exchanger 3 is cooled by the indoor heat. It is pumped to the exchanger 10 side. Next, the two-way valve 6 is closed, the two-way valve 8 is opened, the refrigerant heater 4 is ignited, and the refrigerant heating operation indicated by the dashed arrow in FIG. 4 is started. In this case, the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the indoor heat exchanger 10 to heat the room, passes through the electric expansion valve 5, and becomes low-temperature and low-pressure as in the heat pump operation. Thereafter, the refrigerant enters the refrigerant heater 4 through the two-way valve 8 and is heated, and is sucked into the compressor 1 again.

This air conditioner is shown in FIG.
As in the heat pump operation, the two-way valves 8 and 9a are closed and the two-way valves 6 and 7 are opened, and the four-way valve 2 is switched to perform the cooling operation in the refrigerant circulation path as indicated by the one-dot chain line arrow. It is configured to perform the processing, but details thereof are omitted.

Next, when the outdoor heat exchanger 3 is frosted during the operation of the heat pump, the air conditioner performs the defrosting operation during the operation of the heat pump through the refrigerant circulation path shown by the thick line and the arrow in FIG. It is configured to perform. Specifically, when the outdoor heat exchanger 3 begins to frost, the two-way valve 7 is closed from the heat pump operation state indicated by the solid arrow in FIG. 4 → the two-way valve 6 is closed simultaneously with the ignition of the refrigerant heater 4. By opening the two-way valve 8 → opening the two-way valves 7, 9a, the refrigerant heated by the refrigerant heater 4 passes through the compressor 1 and then passes through the indoor heat exchanger 10, The flow is branched from the defrosting circuit 9 to the flow passing through the outdoor heat exchanger 3.

In this case, since the defrosting circuit 9 has the capillary tube 9b as the throttle, the refrigerant does not extremely flow through the outdoor heat exchanger 3 on the low temperature side.
At the same time as the indoor heating is performed by the refrigerant passing through the indoor heat exchanger 10, the outdoor heat exchanger 3 is defrosted. The refrigerant that has passed through the electric expansion valve 5 through the indoor heat exchanger 10 and the refrigerant that has passed through the two-way valve 7 through the outdoor heat exchanger 3 are connected to the inlet side of the refrigerant heating circuit (the two-way valve 8). Side) and heated again by the refrigerant heater 4.

After the defrosting is completed, the two-way valve 9a is closed, the refrigerant heater 4 is extinguished, the two-way valve 8 is closed, the two-way valve 6 is opened, and the opening of the electric expansion valve 5 is reduced (to a slight degree). The heat pump operation is resumed while regulating the rotation speed of the compressor 1 at a certain frequency or higher. The reason for returning to the heat pump operation in such a procedure is to prevent the liquid from returning to the compressor 1.

Next, control of switching between the refrigerant heating operation and the heat pump operation will be described with reference to FIGS. In FIG. 2, first, the indoor control unit a1 of the indoor unit A
Based on the input signal of the room temperature Ta from the room temperature detector a2 and the input signal of the set temperature Ts from the remote controller or the like, a difference ΔT = Ts−Ta between the two is determined, and the difference ΔT between the two is determined. Is transmitted to the outdoor control unit b1 of the outdoor unit B.

The outdoor controller b1 having received the operation code c uses the operation code c and the input signal of the outside air temperature Ts from the outside air temperature detector b2 based on the operation mode determination table as shown in FIG. Thus, switching between the refrigerant heating operation and the heat pump operation is performed.

Here, the basic concept of the operation mode switching is as follows. Regarding the outside air temperature T0, when the outside air temperature T0 is not so low, an energy-efficient heat pump operation is performed, and when the outside air temperature T0 is low, In the heat pump operation, the heating capacity is significantly reduced in spite of the large power consumption, so that the refrigerant heating operation is performed.

Specifically, as shown in FIG. 3, with respect to ΔT = set temperature Ts−indoor temperature Ta, and outside air temperature T0, threshold values ΔT1 and T01 serving as references for switching between the refrigerant heating operation and the heat pump operation. , T02 are respectively set. Then, threshold values T01, T0 relating to the outside air temperature T0
2 is that the threshold value T02 when switching from the refrigerant heating operation side (left side in FIG. 3) to the heat pump operation side (right side in FIG. 3) is larger than the threshold value T01 when switching from the heat pump operation side to the refrigerant heating operation side. Is also set high.

In the operation mode determination table shown in FIG. 3, (1) T0 ≦ (T01 or T02) and ΔT
> ΔT1, the refrigerant heating operation is performed, and (2) T0 ≦ (T
01 or T02) and ΔT ≦ ΔT1, the high-capacity refrigerant heating operation or the heat pump operation is performed, and (3) T0
> (T01 or T02) and ΔT ≦ ΔT1, the heat pump operation is started, and (4) T0> (T01 or T0
2) and when ΔT> ΔT1, the refrigerant heating operation or the low capacity heat pump operation is specified.

Further, once the operation mode (refrigerant heating operation or heat pump operation) is determined on the basis of the operation mode determination table shown in FIG. Regardless, it is configured to operate in the same operation mode.

Further, in this air conditioner, the setting of the threshold values T01 and T02 of the outside air temperature can be changed by operating a switch on an electric component of the indoor unit A or the outdoor unit B or a remote control device. Is configured.

Also, in FIG. 2, this air conditioner
If the fuel sensor b3 detects that the fuel for heating the refrigerant heater 4 (see FIG. 1) is running out during the refrigerant heating operation, the outdoor control unit b1 immediately stops the operation of the air conditioner and displays the running out of fuel. The unit b4 is configured to display an out-of-fuel condition (for example, lighting a lamp). As the heating fuel, it is preferable to use kerosene, which is a relatively inexpensive fuel, from the viewpoint of reducing the running cost during the refrigerant heating operation.

Next, the operation and effect of this embodiment having the above configuration will be described. According to the present embodiment, when performing defrosting of the outdoor heat exchanger during the heat pump operation of the refrigeration cycle, using the refrigerant heated by the refrigerant heater, simultaneously performing the defrosting of the outdoor heat exchanger, Heating by a heat exchanger can be performed. Therefore, during the defrosting operation during the heat pump operation, a continuous heating operation can be performed without reducing the heating capacity. In addition, by setting the reference temperature for switching between the conventional heat pump operation and the refrigerant heating operation to a level that does not cause frost during the heat pump operation, energy efficiency is higher than that of an air conditioner that prevents frost itself. The ratio of the heat pump operation can be increased, and the running cost can be greatly reduced.

The indoor control unit a1 of the indoor unit A sends the operation code c determined by the difference ΔT = Ts−Ta between the set temperature Ts and the indoor temperature Ta to the outdoor control unit b1 of the outdoor unit B.
The outdoor control unit b1 switches between the refrigerant heating operation and the heat pump operation based on the received operation code c and the outside air temperature Ts, so that the indoor control unit a1 of the indoor unit A
As compared with the case where the signal of the set temperature Ts and the signal of the room temperature Ta need to be transmitted to the outdoor controller b1 of the outdoor unit B from the outside, only the operation code c needs to be transmitted. It is possible to reduce the communication load between the devices.

Also, threshold values T01, T02 of the outside air temperature T0, which is a reference for switching between the refrigerant heating operation and the heat pump operation.
Is that the threshold value T02 when switching from the refrigerant heating operation side to the heat pump operation side is set higher than the threshold value T01 when switching from the heat pump operation side to the refrigerant heating operation side. After the determination is made, the operation is performed in the same operation mode within a predetermined set time irrespective of the change in the temperature condition. Therefore, the refrigerant heating operation and the heat pump operation with respect to the change in the outside air temperature T0 are performed. Can be reduced. Therefore, a decrease in the heating capacity due to the switching can be suppressed, and a decrease in the room temperature Ta can be prevented.

Further, the configuration is such that the setting of the threshold values T01 and T02 of the outside air temperature can be changed by operating the switches on the electric parts of the indoor unit A or the outdoor unit B or the remote controller. In accordance with the installation conditions and use conditions of the air conditioner, it is possible to adjust so that the switching between the refrigerant heating operation and the heat pump operation based on the outside air temperature T0 is performed optimally. Further, when the fuel sensor b3 detects a fuel shortage during the refrigerant heating operation, the outdoor control unit b1 immediately stops the operation of the air conditioner and causes the fuel shortage display unit b4 to display a fuel shortage display. Therefore, compared to the case where the operation is automatically switched to the heat pump operation when the fuel runs out and the operation is continued, the user who expects a feeling of high heating by the refrigerant heating operation is heated by the switching to the heat pump operation. Avoids discomfort caused by reduced ability.

[0046]

According to the present invention, when the outdoor heat exchanger is defrosted during the heat pump operation of the refrigeration cycle, the outdoor heat exchanger is defrosted using the refrigerant heated by the refrigerant heater. At the same time, heating by the indoor heat exchanger can be performed. For this reason, during the defrosting operation during the heat pump operation, a continuous heating operation can be performed without reducing the heating capacity.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a refrigeration cycle (defrosting operation state during a heat pump operation) in an embodiment of an air conditioner according to the present invention.

FIG. 2 is a block diagram showing an outline of a control system in the air conditioner shown in FIG.

FIG. 3 is a view showing an operation mode determination table of the air conditioner shown in FIG. 1;

FIG. 4 is a block diagram showing a refrigeration cycle of the air conditioner shown in FIG. 1 in another operation state.

FIG. 5 is a block diagram showing a refrigeration cycle in a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Refrigerant superheater 5 Electric expansion valve (expansion mechanism) 6, 7, 8, 9a Two-way valve 9 Defrosting circuit 9b Capillary tube 10 Indoor heat exchanger A Indoor unit a1 Indoor control unit a2 Room temperature detector B Outdoor unit b1 Outdoor control unit b2 Outside air temperature detector b3 Fuel sensor b4 Out-of-fuel display unit c Operation code Ta Indoor temperature Ts Set temperature T0 Outside air temperature T01, T02 Threshold value of outside air temperature

Claims (6)

[Claims] 1. A heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, an expansion mechanism, and an outdoor heat exchanger are connected by a refrigerant circuit, and the expansion mechanism and the outdoor heat exchanger in the refrigeration cycle. And a refrigerant heating circuit having a refrigerant heater connected between the suction side of the compressor and a discharge side of the compressor in the refrigeration cycle, and between the outdoor heat exchanger and the four-way valve. And a defrosting circuit for connecting the, when performing the defrosting of the outdoor heat exchanger during the heat pump operation of the refrigeration cycle, after the refrigerant heated by the refrigerant heater passes through the compressor, The flow through the indoor heat exchanger and the flow from the defrost circuit to the flow through the outdoor heat exchanger are branched, and the flows of these branched refrigerants join at the inlet of the refrigerant heating circuit, and again the refrigerant To the heater An air conditioner characterized in that it is configured to be heated me. 2. A room temperature detector for detecting an indoor temperature, and an outside air temperature detector for detecting an outside air temperature, wherein a difference between a set temperature and the room temperature detected by the room temperature detector is detected. The air conditioner according to claim 1, wherein switching between the refrigerant heating operation and the heat pump operation during the heating operation is performed based on the outside air temperature detected by the air conditioner. 3. An indoor unit including the indoor heat exchanger, and an outdoor unit including the outdoor heat exchanger, wherein the indoor unit inputs the room temperature detector and a room temperature detected by the room temperature detector. An indoor control unit that determines an operation code based on the set temperature and the outdoor unit, the outdoor unit includes the outdoor air temperature detector and an outdoor control unit, and the outdoor control unit includes The switching between the refrigerant heating operation and the heat pump operation during the heating operation is determined based on the operation code transmitted from the indoor control unit and the outside air temperature detected by the outside air temperature detector. 2. The air conditioner according to 2. 4. A threshold value of the outside air temperature, which is a reference for switching between the refrigerant heating operation and the heat pump operation, switches from the heat pump operation to the refrigerant heating operation when switching from the refrigerant heating operation to the heat pump operation. The threshold value is set higher than the threshold value in the case.
Or the air conditioner according to 3. 5. The air conditioner according to claim 4, wherein the setting of the threshold value of the outside air temperature can be changed. 6. If the fuel for heating the refrigerant heater runs out of fuel during the refrigerant heating operation, the operation is stopped and an out-of-fuel indication is displayed. The air conditioner according to claim 1.