JP2002081714A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner capable of performing defrosting operation efficiently according to the outside temperature and the environment of an installed place. SOLUTION: This air conditioner has a compressor 2, an outdoor heat exchanger 3 and a decompressing mechanism 4, and it is formed in such a manner that it is capable of defrosting the frost formed on the outdoor heat exchanger 3 functioning as an evaporator at the time of space heating operation. If the outside temperature doa is under the standard temperature DOALO, the operating frequency of the compressor 2 is set at the operating frequency that is higher than the standard operating frequency to perform defrosting operation. Moreover, it is formed in such a manner that whether the operating frequency of the compressor 2 at the time of the defrosting operation is performed by the first standard operating frequency or the second standard operating frequency that is set higher than the first standard operating frequency can be manually set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner capable of performing a heating operation, a defrosting operation, and the like.

[0002]

2. Description of the Related Art A conventional air conditioner is provided with a compressor, an outdoor heat exchanger, a pressure reducing mechanism, and an indoor heat exchanger in a refrigerant circuit thereof, and the outdoor heat exchanger functions as an evaporator. The heating operation can be performed by making the indoor heat exchanger function as a condenser. At this time, if the heating operation is continued, frost is formed on the outdoor heat exchanger that functions as an evaporator outdoors where the temperature is low. At this time, if the generated frost is left as it is, the heat exchange efficiency of the outdoor heat exchanger decreases, and in such a case, the air conditioner performs the defrosting operation.

[0003] Defrosting operation is to melt and remove frost generated in the outdoor heat exchanger by giving the amount of heat that should have been generally released from the indoor heat exchanger to the room to the outdoor heat exchanger. It is assumed that. Further, in such a defrosting operation, the outdoor heat exchanger temperature detected by a thermistor provided in the outdoor heat exchanger is compared with a predetermined defrost start heat exchanger temperature, and the outdoor heat exchanger temperature is defrosted. When the temperature becomes lower than the heat exchanger temperature, it is determined that there is a defrost request, and the process is started.

[0004]

Heretofore, conventionally, the defrosting operation has been performed at the same operating frequency under the above-mentioned defrosting operation under any environmental conditions. That is, a predetermined operating frequency is used so that there is no residual melting when the outside air temperature is, for example, −5 ° C. or more. However, in actual use, in an area of extremely low temperature (for example, -10 to -20 ° C), a resistance to melt frost more than the above assumed environmental conditions is required,
There is a problem that the defrosting time is longer than expected at the time of design. In addition, such an extension of the defrosting time indicates that the supply of heat to the room is not performed during that time as described above, and thus causes a decrease in room temperature.

In order to prevent the defrosting time from being extended, if the operating frequency of the compressor during the defrosting operation is set to a high value in advance, an excessive outdoor unit compressor noise is generated at a normal outside air temperature which is not extremely low. Also, there is a problem that the indoor unit refrigerant passing sound is generated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to provide an air conditioner capable of efficiently performing a defrosting operation according to the outside air temperature and the environment of an installation place. To provide.

[0007]

Therefore, an air conditioner according to the present invention has a compressor 2, an outdoor heat exchanger 3, and a pressure reducing mechanism 4, and functions as an evaporator during a heating operation.
When the outside air temperature doa is lower than the reference temperature DOALO, in the air conditioner configured to be capable of defrosting the frost on the compressor 2, the defrosting operation of the compressor 2 is performed at an operation frequency higher than the reference operation frequency. Features.

In the air conditioner of the first aspect, if the outside air temperature doa is lower than the reference temperature DOALO, the compressor 2 is operated to perform a defrosting operation at an operation frequency higher than the reference operation frequency. Thus, the outside air temperature doa
When the temperature is low, the operating frequency of the compressor 2 is increased to control the defrosting performance, so that the defrosting operation according to the outside air temperature doa at that time can be performed, and the defrosting time can be reduced. Can be achieved.

An air conditioner according to a second aspect of the present invention has a compressor 2, an outdoor heat exchanger 3, and a pressure reducing mechanism 4, and removes frost on the outdoor heat exchanger 3 functioning as an evaporator during a heating operation. In the air conditioner configured to allow frost, the operation frequency of the compressor 2 during the defrosting operation is performed at the first reference operation frequency or at the second reference operation frequency set higher than the first reference operation frequency. It is characterized in that it can be manually set.

In the air conditioner of the second aspect, the operation frequency of the compressor 2 during the defrosting operation is set to the first reference operation frequency or the second reference operation is set to be higher than the first reference operation frequency. It is configured to be able to manually set whether to perform with frequency. As a result, it becomes possible to select an operation frequency at the time of the defrosting operation according to the environmental condition of the place where the air conditioner is installed. Accordingly, for example, when the air conditioner is installed in a cold region or a heavy snowfall region, the defrosting time can be reduced by previously setting the second reference operation frequency having an operation frequency higher than usual. Can be planned.

An air conditioner according to a third aspect of the present invention includes a compressor 2, an outdoor heat exchanger 3, and a pressure reducing mechanism 4, and removes frost on the outdoor heat exchanger 3 functioning as an evaporator during a heating operation. In the air conditioner configured to allow frost, the operation frequency of the compressor 2 during the defrosting operation is performed at the first reference operation frequency or at the second reference operation frequency set higher than the first reference operation frequency. In addition to the above configuration, if the outside air temperature doa is lower than the reference temperature DOALO, the operation frequency of the compressor 2 is defrosted at an operation frequency higher than each of the reference operation frequencies. .

In the air conditioner according to the third aspect, the operating frequency of the compressor 2 can be manually set in accordance with the environmental conditions of the installation location, and the operating frequency can be set in accordance with the outside air temperature doa at that time. Because it is configured to be variable,
The defrosting operation can be performed at a more appropriate operation frequency, and the defrosting time can be shortened.

Further, in the air conditioner according to the fourth aspect, when the operating frequency of the compressor 2 is increased, the pressure reducing mechanism 4
The feature is to increase the opening degree.

In the air conditioner according to the fourth aspect, the opening of the pressure reducing mechanism 4 is increased with an increase in the operating frequency. Thereby, since the circulation amount can be increased, the defrosting performance can be further improved, and the defrosting time can be further reduced.

[0015]

Next, specific embodiments of the air conditioner of the present invention will be described in detail with reference to the drawings. FIG. 1 is a refrigerant circuit diagram illustrating a configuration of an air conditioner 1 according to an embodiment of the present invention.

As shown in FIG. 1, the air conditioner 1 includes:
It is a heat pump type air conditioner including a compressor 2, an outdoor heat exchanger 3, an electric expansion valve 4 (decompression mechanism), and an indoor heat exchanger 5, and a refrigerant circuit is provided so that refrigerant from the compressor 2 is circulated. It is configured. That is, the discharge side 2a and the suction side 2b of the compressor 2 are connected to the primary ports of the four-way switching valve 6, respectively. Then, one of the secondary ports of the four-way switching valve 6 passes through the outdoor heat exchanger 3 provided with the outdoor fan 8, the electric expansion valve 4, and the indoor heat exchanger 5 provided with the indoor fan 9, respectively. Of the four-way switching valve 6
The refrigerant circuit leading to the next port is constituted by a refrigerant pipe. Then, from the four-way switching valve 6, the accumulator 7
To return to the suction side 2b of the compressor 2 via the. The outdoor heat exchanger 3 is provided with an outdoor heat exchange temperature thermistor 10 for detecting the temperature of the outdoor heat exchanger.
Further, an outdoor temperature thermistor (not shown) for detecting the outdoor temperature doa is provided outdoors.

A case in which a cooling operation and a heating operation are performed in the refrigerant circuit of the air conditioner 1 will be described. That is, during the cooling / heating operation, the electric expansion valve 4 is adjusted to a predetermined opening degree, and the outdoor fan 8 and the indoor fan 9 are driven at a predetermined rotation speed. When performing the cooling operation, the refrigerant discharged from the compressor 2 is circulated as indicated by a solid arrow, and the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchanger 5 functions as an evaporator. This cools the indoor air. In the case of performing the heating operation, the refrigerant discharged from the compressor 2 is circulated as indicated by a dashed arrow, and the indoor heat exchanger 5 functions as a condenser and the outdoor heat exchanger 3 functions as an evaporator. Thereby, it is configured to heat the indoor air.

By the way, if the above-described heating operation is continuously performed, frost is formed on the outdoor heat exchanger 3 which functions as an evaporator outdoors at low temperatures. If the frost is left untreated, the heat exchange capacity of the outdoor heat exchanger 3 is reduced. In such a case, the control is performed so that the defrosting operation is automatically performed. Here, the defrosting operation in the present embodiment will be described. During the heating operation, the outdoor heat exchanger temperature detected by the outdoor heat exchange temperature thermistor 10 attached to the outdoor heat exchanger 3 is set in advance. A comparison with the defrost start heat exchanger temperature (for example, -12 ° C) is performed, and when the outdoor heat exchanger temperature becomes equal to or lower than the defrost start heat exchanger temperature,
The defrosting operation is performed when it is determined that a defrost request has been made. In the defrosting operation, the outdoor fan 8 and the indoor fan 9 in the refrigerant circuit of FIG. 1 are stopped, and the four-way switching valve 6 is switched in the solid line direction to supply the outdoor heat exchanger 3 with the discharged gas from the compressor 2. It is performed in a reverse cycle defrosting operation by supplying a refrigerant. At this time, the operating frequency of the compressor 2 during the defrosting operation is configured to be switchable and set based on the outside air temperature doa and the environmental conditions of the installation location, as described in detail below.

The operation frequency control of the compressor 2 during the defrosting operation will be described. FIG. 2 is an explanatory diagram for explaining the operation frequency control. The figure shows the assumed number of operating frequencies that are switched and set according to the outside air temperature doa and the environmental conditions of the installation location, where indicates the operating frequency when the outside air temperature doa is considered, and indicates the operating frequency when the installation location is considered. The operating frequency or the operating frequency when both the outside air temperature doa and the installation location are considered are shown.

First, the operation frequency control based on the outside air temperature doa will be described. When a defrosting operation start command is issued during the heating operation, the outside air temperature doa detected by the outside air temperature thermistor is changed to a preset reference temperature DOA.
A determination is made whether the temperature is below LO (eg, 0 ° C.). Here, the outside air temperature doa is equal to the reference temperature DOALO.
If the above is the case, the first operation frequency, which is the operation frequency during normal defrosting,
When the defrosting operation is performed at the reference operation frequency (for example, 70 Hz) and the outside air temperature doa is lower, the second reference operation frequency (for example, 74 Hz) having an operation frequency higher than the first reference operation frequency is used. ) Is controlled so that the defrosting operation is performed.

Next, operation frequency control based on environmental conditions of a place where the air conditioner 1 is installed will be described.
In the present embodiment, the air conditioner 1 is operated at an extremely low temperature (for example, -1).
(0 ° C to -20 ° C) in a cold region or a very heavy snow region where the temperature is not extremely low, and when it is installed in a normal region where the temperature is not extremely low, the standard operation frequency for defrosting is set. It is configured so that it can be performed manually. That is, the first reference operation frequency (for example, 70 Hz) is set in a normal area, and the second reference operation frequency set higher than the first reference operation frequency is set in a cold area or a heavy snowfall area. The frequency (for example, 78 Hz) is configured to be selectable. As a specific switching method, for example, a jumper wire or the like that can be electrically turned on / off is provided on a control printed circuit board (not shown), and the above operation is performed depending on whether the jumper wire is cut or not. The frequency can be switched.
That is, when the jumper wire is electrically connected (ON state), the defrosting operation is performed at the first reference operating frequency, and when the jumper wire is cut (OFF state), the second reference operation frequency is used. It is set so that the defrosting operation is performed at the frequency.

It is also possible to control the operating frequency in consideration of both the outside air temperature doa and the environmental conditions of the installation place. In this case, the operating frequency of the compressor 2 is higher than any of the operating frequencies set in the above-described operating frequency control (for example,
(82 Hz). Note that such a defrosting operation is terminated when the outdoor heat exchanger temperature reaches a preset defrosting operation end heat exchanger temperature or when a preset defrosting time has elapsed, and thereafter, again. It is controlled to return to the heating operation.

FIG. 3 shows the compressor 2 during the defrosting operation.
4 is a control flowchart for performing the switching control of the operating frequency of FIG. First, when a defrosting operation start command is issued in step S1, the process proceeds to step S2, where 0 is substituted for the values of a and b that are correction amounts of the operating frequency of the compressor 2.
Next, in step S3, the outside air temperature doa detected by the outside air temperature thermistor is changed to a predetermined reference temperature DOAL.
It is determined whether it is less than O (for example, 0 ° C.). Here, if the outside air temperature doa is lower, step S4
Then, the correction amount a is set to a = 4 (Hz), and then the process proceeds to step S5. On the other hand, if the outside air temperature doa is equal to or higher than the reference temperature DOALO in step S3, the process also proceeds to step S5. In step S5, a determination is made as to whether the manual setting of the operating frequency has been performed. If the manual setting has been performed, the process proceeds to step S6, and the correction amount b is set to b = 8 (Hz).
Then, the process proceeds to step S7. On the other hand, if the manual setting has not been performed in step S5, the process also proceeds to step S7. In step S7, a first reference operation frequency (for example,
(70 Hz), the values of a and b, which are the above-mentioned correction amounts, are added, and this is set as a new operating frequency of the compressor 2 so that the defrosting operation is started.

As described above, according to the embodiment of the air conditioner 1, the outside air temperature d detected by the outside air temperature thermistor is obtained.
If oa is lower than the reference temperature DOALO, the operation frequency of the compressor 2 is defrosted at an operation frequency higher than the normal reference operation frequency. Thus, the outside air temperature d
When oa is low, by controlling the operating frequency of the compressor 2 to increase the defrosting performance, the defrosting operation can be performed according to the outside air temperature doa at that time, and the defrosting time can be reduced. Can be shortened. In addition, the configuration is such that the operation frequency at the time of the defrosting operation is set to be the first reference operation frequency or the second reference operation frequency set higher than the first reference operation frequency, so that it can be manually switched and set. When installed in a heavy snowfall area, it becomes possible to perform a defrosting operation by selecting a second reference operation frequency higher than usual, so that it is possible to perform a defrosting operation according to the environmental conditions of the installation location. In addition, the defrosting time can be reduced. Further, by enabling such a switching setting, it is not necessary to set a higher operating frequency during the defrosting operation of all the air conditioners 1 in consideration of installation in a cold region or the like. Therefore, the outdoor unit compressor sound and the indoor unit refrigerant passage sound caused by this can be suppressed.

Next, a method for controlling the electric expansion valve 4 in the embodiment of the air conditioner 1 will be described. That is, in the present embodiment, during the defrosting operation, the opening degree control of the electric expansion valve 4 is also performed in addition to the operation frequency control described above. That is, when the control for increasing the operating frequency of the compressor 2 is performed, the opening of the electric expansion valve 4 is controlled to be increased accordingly. As a result, the circulation amount of the refrigerant flowing through the refrigerant circuit can be increased, whereby the defrosting performance can be further improved, and the defrosting time can be further reduced.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be implemented with various modifications within the scope of the present invention. That is, in the present embodiment, the defrosting time is shortened by controlling the operating frequency of the compressor 2 and the opening degree of the electric expansion valve 4, but in addition, the control for avoiding unmelted frost remains. In other words, it is also possible to implement control such as setting the defrost time slightly longer than usual or setting the defrost operation end heat exchanger temperature higher than usual. . Further, in the above embodiment, the case where the reverse cycle defrosting operation is performed has been described as an example. However, a defrosting operation by another method, for example, a bypass passage leading from the compressor 2 to the outdoor heat exchanger 3 is provided,
The above control can be applied to a defrosting operation or the like by supplying hot gas through the bypass passage.

[0027]

As described above, according to the air conditioner of the first aspect, when the outside air temperature is low, the operating frequency of the compressor is controlled to increase the defrosting performance. In addition to performing the defrosting operation according to the above, the defrosting time can be shortened.

According to the air conditioner of the second aspect, the operating frequency during the defrosting operation can be manually selected according to the environmental conditions of the place where the air conditioner is installed.
The defrosting time can be reduced.

Further, according to the air conditioner of the third aspect, it is possible to manually set the operating frequency of the compressor in accordance with the environmental conditions of the installation place, and to set the operating frequency in accordance with the outside air temperature at that time. Since it is configured to be variable, the defrosting operation can be performed at a more appropriate operation frequency, and the defrosting time can be shortened.

According to the air conditioner of the fourth aspect, the amount of circulation can be increased by increasing the opening of the pressure reducing mechanism as the operating frequency increases, so that the defrosting performance can be further improved. It is possible to further shorten the defrosting time.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram for explaining operating frequency control of a compressor in the air conditioner according to the first embodiment.

FIG. 3 is a control flowchart for controlling switching of an operating frequency of a compressor in the air conditioner according to the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Compressor 3 Outdoor heat exchanger 4 Electric expansion valve (pressure reduction mechanism) 5 Indoor heat exchanger 6 Four-way switching valve 10 Outdoor heat exchange temperature thermistor doa Outside air temperature DOALO Reference temperature

Claims (4)

[Claims] 1. A frost on an outdoor heat exchanger (3) having a compressor (2), an outdoor heat exchanger (3), and a pressure reducing mechanism (4) and functioning as an evaporator during a heating operation is removed. If the outside air temperature (doa) is lower than the reference temperature (DOALO) in the air conditioner configured to allow frost, the operation frequency of the compressor (2) may be defrosted at an operation frequency higher than the reference operation frequency. A characteristic air conditioner. 2. A frost on an outdoor heat exchanger (3) having a compressor (2), an outdoor heat exchanger (3), and a pressure reducing mechanism (4) and functioning as an evaporator during a heating operation is removed. Compressor (2) for defrosting operation in an air conditioner configured to allow frost
An air conditioner characterized in that it is configured to be able to manually set whether to perform the operation frequency at a first reference operation frequency or at a second reference operation frequency set higher than the first reference operation frequency. 3. A frost on an outdoor heat exchanger (3) having a compressor (2), an outdoor heat exchanger (3), and a pressure reducing mechanism (4) and functioning as an evaporator during a heating operation is removed. Compressor (2) for defrosting operation in an air conditioner configured to allow frost
It is possible to manually set whether the operation frequency is performed at the first reference operation frequency or at the second reference operation frequency set higher than the first reference operation frequency, and the outside air temperature (doa) is set to the reference temperature. An air conditioner characterized by performing a defrosting operation at an operating frequency higher than each of the reference operating frequencies when the operating frequency of the compressor (2) is lower than (DOALO). 4. The air according to claim 1, wherein when the operating frequency of the compressor (2) is increased, the opening of the pressure reducing mechanism (4) is increased. Harmony machine.