JPH10259972A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a base for placing an outdoor heat exchanger from being frozen in case of heating operation at low fresh air temperature. SOLUTION: An air conditioner is adapted such that there are coupled in order a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a pressure reducing device 4, and an indoor heat exchanger 5 to form a refrigerant circuit, and heat transfer pipes of the outdoor heat exchangers 3 are disposed longitudinally in two lines. In the air conditioner, upper and lower two coupling parts which couple upper ends and lower ends of the front row and the back row of the heat transfer pipes are taken as middle parts 3a, 3b of the outdoor heat exchanger 3, and parallel bypass circuits including opening/closing valves 6a, 6b are provided between the two middle parts 3a, 3b and a discharge side of the compressor 1. upon cooling and heating operations both opening/closing valves 6a, 6b are closed, and upon defrosting operation both opening/closing valves are opened whereby part of refrigerant gas discharged from the compressor 1 is supplied to the two middle parts 3a, (3b. Further, upon heating operation where fresh air temperature is lower than predetermined temperature the opening/closing valve 6a is closed while the opening/closing valve 6b is opened to supply the part of the refrigerant gas discharged from the compressor 1 to the middle part 3b.

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 preventing icing of a base on which an outdoor heat exchanger is mounted during a heating operation at a low outdoor temperature.

[0002]

2. Description of the Related Art As shown in FIG. 4, for example, a conventional air conditioner includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3,
There is a refrigerant circuit in which a pressure reducing device 4 and an indoor heat exchanger 5 are sequentially connected by piping, and a high-temperature and high-pressure refrigerant gas discharged from the compressor 1 during a heating operation passes through the four-way valve 2 as shown by a solid line arrow. After being sent to the exchanger 5 and heat exchange with the indoor air, it is decompressed and liquefied by the decompression device 4, gasified by the heat exchange with the outdoor air in the outdoor heat exchanger 3, and passed again through the four-way valve 2 to the compressor 1. It returns to the suction side. In addition, during the cooling operation and the defrosting operation for removing frost from the outdoor heat exchanger 3, the four-way valve 2 is switched, so that the flow of the refrigerant changes as indicated by the dashed arrow, and the outdoor heat exchanger 3 and the indoor heat exchanger 3 The operation of the exchanger 5 is reversed.

[0003] In the defrosting operation, high-temperature and high-pressure refrigerant gas flows into the outdoor heat exchanger 3, and the refrigerant flowing into the outdoor heat exchanger 3 is deprived of heat by heat exchange with outdoor air. Since the temperature decreases, it takes time to defrost the outlet side where the flow of the refrigerant is downstream. Therefore, as means for shortening the defrosting time, a bypass circuit having an on-off valve 6 'is provided between the discharge side of the compressor 1 and the intermediate portions 3a and 3b of the outdoor heat exchanger 3, and a white arrow is provided. As shown in FIG. 2, a part of the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is supplied to the intermediate portions 3a and 3b of the outdoor heat exchanger 3.

FIG. 5 shows an example of pipe connection of the outdoor heat exchanger 3. The outdoor heat exchanger 3 is arranged in two rows in front and rear with respect to an air flow generated by the operation of the blower fan 7 shown in FIG. The upper and lower connecting portions for connecting the upper ends and the lower ends of the heat transfer tubes in the front and rear rows, respectively, are defined as intermediate portions 3a and 3b of the outdoor heat exchanger 3, and the intermediate portions 3a and 3b and the compressor 1 A bypass circuit having the above-described on-off valve 6 ′ is provided between the discharge side and the on-off valve 6 ′ during the defrosting operation, and a part of the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is subjected to outdoor heat exchange. By being bypassed to the intermediate portions 3a and 3b of the heat transfer tubes of the heat exchanger 3, the outlet side (the pressure reducing device 4)
A high-temperature refrigerant gas is caused to flow on the downstream side of the outdoor heat exchanger 3, whereby delay of defrosting on the downstream side is eliminated, and the defrosting time of the entire outdoor heat exchanger 3 is shortened.

[0005] However, in the above-described conventional configuration, the temperature of the outdoor heat exchanger drops during the heating operation at a low outdoor temperature even if the outdoor heat exchanger 3 is not frosted. There is a problem that the base that forms the lower part of the outdoor unit on which the camera is mounted freezes.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is an air conditioner capable of preventing icing of a base on which an outdoor heat exchanger or the like is mounted during a heating operation at a low outside temperature. The purpose is to provide a machine.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and comprises a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger. In the air conditioner, the heat transfer tubes of the outdoor heat exchanger are formed in two rows before and after the air flow generated by the rotation of the outdoor fan. The upper and lower two connecting portions that respectively connect the upper end and the lower end of each other are defined as intermediate portions of the outdoor heat exchanger, and between these two intermediate portions and the discharge side of the compressor, a parallel connection including an on-off valve is provided. A bypass circuit is provided, both the on-off valves are closed during cooling and heating operations, and both on-off valves are opened during defrosting operation, and a part of the refrigerant gas discharged from the compressor is supplied to the two intermediate portions, Open during heating operation when the outside air temperature is lower than the predetermined temperature. Closing one of the valves, opens the second on-off valve, which is configured and supplies part of the discharge refrigerant gas in the compressor in an intermediate portion of the other.

[0008] Further, one of the on-off valves is provided in the middle of the upper end of the outdoor heat exchanger, and the other on-off valve is provided in the middle of the lower end of the outdoor heat exchanger.

Further, the other on-off valve is configured to be repeatedly opened and closed at a predetermined cycle for a predetermined time during a heating operation in which the outside air temperature is equal to or lower than a predetermined temperature.

[0010] In addition, the refrigerant flowing vertically above and below the middle stage of the heat exchanger tubes in the front or rear row of the outdoor heat exchanger is made to flow out of the middle stage of the rear or front heat exchanger tubes.

[0011] Further, a solenoid valve is used as the on-off valve. Further, an electronic expansion valve is used as the on-off valve.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS With the above configuration, an air conditioner capable of preventing icing of a base on which an outdoor heat exchanger or the like is mounted during a heating operation at a low outside air temperature.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a refrigerant circuit of an air conditioner, in which 1 is a compressor, 2 is a four-way valve for switching the flow of refrigerant discharged from the compressor 1 in accordance with a heating operation, a cooling operation, and the like.
Are the outdoor heat exchangers arranged in two rows before and after the airflow,
Is a decompression device using a capillary tube or the like, 5 is an indoor heat exchanger, and these are sequentially connected by piping, and the compressor 1
Opening / closing valve composed of a solenoid valve or an electronic expansion valve between the discharge side of the heat exchanger and the intermediate portions 3a and 3b of the heat transfer tubes of the outdoor heat exchanger 3.
A parallel bypass circuit comprising 6a, 6b is provided.
Reference numeral 7 denotes an outdoor fan controlled by an outdoor control unit (not shown), and reference numeral 8 denotes an indoor fan controlled by an indoor control unit (not shown).

In the above configuration, the refrigerant during the heating operation circulates as indicated by the solid line arrow, and the refrigerant gas compressed to a high temperature and a high pressure by the compressor 1 passes through the four-way valve 2 and flows through the indoor heat exchanger 5. The heat is exchanged with the indoor air by the indoor fan 8, the liquid is decompressed and liquefied by the decompressor 4, and while flowing through the outdoor heat exchanger 3, the heat is exchanged with the outdoor air by the outdoor fan 7 to be gasified and compressed again through the four-way valve 2. Return to the suction side of machine 1. During the heating operation, when the temperature of the outdoor heat exchanger 3 detected by the temperature detecting means (not shown) becomes equal to or lower than a predetermined value, the four-way valve 2 is switched to the defrosting operation. Note that the dashed arrows shown in FIG. 1 indicate the flow of the refrigerant during the cooling operation and the defrosting operation.

As shown in FIG. 2, in this embodiment,
The two on-off valves 6a and 6b are closed during the cooling and heating operations, and the two on-off valves 6a and 6b are opened during the defrosting operation. As shown by the white arrows in FIG. A part is supplied to the two intermediate portions 3a and 3b, and is provided between an upper end intermediate portion 3a of the outdoor heat exchanger 3 and a discharge side of the compressor 1 during a heating operation in which the outside air temperature is equal to or lower than a predetermined temperature. The on / off valve 6a provided is closed, and the on / off valve 6b provided between the lower end intermediate portion 3b of the outdoor heat exchanger 3 and the discharge side of the compressor 1 is opened, and one of the refrigerant gas discharged from the compressor is opened. The part is the intermediate part 3b
It is configured to be supplied to.

FIG. 3 shows a piping connection configuration of the outdoor heat exchanger 3. The outdoor heat exchanger 3 is mounted on a base 9 below the outdoor unit, and is arranged in two rows before and after the air flow generated by the operation of the outdoor fan 7. The upper and lower connecting portions connecting the lower end and the lower end are intermediate portions 3a and 3b of the outdoor heat exchanger 3, and the opening and closing described above is performed between the intermediate portions 3a and 3b and the discharge side of the compressor 1. A parallel bypass circuit with valves 6a, 6b is provided. In addition, an inlet and an outlet through which the refrigerant enters and exits during a cooling operation, a heating operation, and the like are provided in the middle of the front row and the rear row.

In such a configuration, during a heating operation in which the outside air temperature is equal to or lower than a predetermined temperature (low temperature), the on-off valve 6b is opened, and the outdoor heat closest to the base 9 as shown by a white arrow in FIG. The compressor 1 is installed in the intermediate portion 3b of the heat transfer tube of the exchanger 3.
By bypassing a part of the warmer refrigerant gas discharged more, the temperature of the base 9 of the outdoor heat exchanger 3 can be increased to prevent the base 9 from freezing. Since the heating capacity is reduced by the bypass, the reduction of the heating capacity can be eliminated by repeatedly performing the bypass time for a predetermined time and a predetermined cycle.

[0018]

As described above, during the heating operation in which the outside air temperature is equal to or lower than the predetermined temperature (low temperature), the warm refrigerant gas discharged from the compressor to the middle portion of the heat transfer tube of the outdoor heat exchanger closest to the base. By bypassing a part of the air conditioner, it is possible to increase the temperature of the base of the outdoor heat exchanger and thereby prevent the base ice from forming.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of an air conditioner showing one embodiment of the present invention.

FIG. 2 is a diagram showing an operation relationship of an on-off valve according to an embodiment of the present invention.

FIG. 3 is a piping connection configuration diagram of an outdoor heat exchanger according to an embodiment of the present invention.

FIG. 4 is a refrigerant circuit diagram of an air conditioner showing a conventional example.

FIG. 5 is a piping connection configuration diagram of an outdoor heat exchanger showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 3a, 3b Intermediate part 4 Pressure reducing device (capillary tube) 5 Indoor heat exchanger 6a, 6b Open / close valve (solenoid valve or electronic expansion valve) 7 Outdoor fan 8 Indoor fan 9 Base

Claims (6)

[Claims] 1. A compressor, a four-way valve, an outdoor heat exchanger,
The decompression device and the indoor heat exchanger are sequentially connected to form a refrigerant circuit, and the heat transfer tubes of the outdoor heat exchanger are arranged in two rows in front and rear with respect to the air flow generated by the rotation of the outdoor fan. In the conditioner, the upper and lower two coupling portions that couple the upper end and the lower end of the front row and the rear row of the heat transfer tube respectively to an intermediate portion of the outdoor heat exchanger, and the two intermediate portions and the discharge side of the compressor. A parallel bypass circuit provided with a respective on-off valve is provided between the on-off valves during cooling and heating operations, and both on-off valves are opened during defrosting operation. Part is supplied to the two intermediate parts, and one of the on-off valves is closed during a heating operation in which the outside air temperature is equal to or lower than a predetermined temperature,
An air conditioner wherein the other on-off valve is opened and a part of the refrigerant gas discharged from the compressor is supplied to the other intermediate portion. 2. The open / close valve according to claim 1, wherein one of the open / close valves is provided at a middle portion of an upper end of the outdoor heat exchanger, and the other open / close valve is provided at a middle portion of a lower end of the outdoor heat exchanger.
The air conditioner as described. 3. The air conditioner according to claim 1, wherein the other on-off valve is repeatedly opened and closed at a predetermined cycle for a predetermined time during a heating operation in which the outside air temperature is equal to or lower than a predetermined temperature. 4. A refrigerant flowing vertically above and below a middle stage of a heat transfer tube in a front row or a rear row of the outdoor heat exchanger is discharged from a middle stage of a heat transfer tube in a rear row or a front row. 2. The air conditioner according to 1. 5. The air conditioner according to claim 1, wherein an electromagnetic valve is used as the on-off valve. 6. The air conditioner according to claim 1, wherein an electronic expansion valve is used as the on-off valve.