JP4345178B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner, and more particularly to an outdoor heat exchanger and a configuration of a refrigerant circuit around the outdoor heat exchanger.
[0002]
[Prior art]
In the conventional air conditioner, as shown in the refrigerant circuit diagram of FIG. 4, 1 is a compressor that compresses refrigerant vapor, and 5 is a four-way valve that switches the flow of refrigerant discharged from the compressor 1 in accordance with the operation mode. , 6 is an indoor heat exchanger that is installed indoors and performs heat exchange of the refrigerant with the indoor air, 7 is an electronic expansion valve that expands through the passage of the refrigerant, and 8 is an outdoor installation that exchanges heat of the refrigerant with the outside air. It was the structure of the outdoor heat exchanger which performs.
[0003]
[Problems to be solved by the invention]
However, in the above configuration, when the outdoor temperature is low and 0 ° C. or lower in the heating operation mode, the temperature of the refrigerant liquid flowing into the outdoor heat exchanger functioning as an evaporator needs to be equal to or lower than the outdoor temperature. There is a problem that the surface of the outdoor heat exchanger that transmits the heat of evaporation to the outside becomes a temperature lower than the outside air of 0 ° C. or less, and the water vapor of the outside air forms frost on the surface of the outdoor heat exchanger.
In view of the above problems, an object of the present invention is to provide an air conditioner that hardly frosts on an outdoor heat exchanger at a low outside air temperature of about 0 ° C. or less and that can efficiently perform a heating operation. .
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention uses a four-way valve, an indoor heat exchanger, an electronic expansion valve, an outdoor heat exchanger, and the four-way valve to cool the refrigerant discharged from the discharge port of the compressor. In an air conditioner comprising a heat pump refrigeration cycle that circulates to the mouth,
The path of the outdoor heat exchanger is divided into a main path and a sub path and connected in parallel, a first auxiliary electronic expansion valve is provided on the electronic expansion valve side of the main path, and a second auxiliary is provided on the four-way valve side of the sub path While providing an electronic expansion valve, an outdoor temperature sensor is provided in the vicinity of the outdoor heat exchanger, and a refrigerant temperature sensor is provided at an inlet of the main path on the first auxiliary electronic expansion valve side and an inlet of the sub path on the electronic expansion valve side. Providing a control unit for controlling the electronic expansion valve, the first auxiliary electronic expansion valve, and the second auxiliary electronic expansion valve in accordance with the detected temperature of these temperature sensors,
In the heating operation mode, the control unit throttles the electronic expansion valve so that the refrigerant temperature at the sub-pass inlet is 0 ° C. or higher, and the first auxiliary electronic expansion valve is used for the refrigerant temperature at the main-pass inlet is lower than the outdoor temperature. The second auxiliary electronic expansion valve is throttled so that the refrigerant flows through both the main path and the sub path.
[0005]
In the cooling operation mode, the control unit opens the first auxiliary electronic expansion valve, and the second auxiliary electronic expansion valve is controlled to be throttled so that the refrigerant flows in both the main path and the sub path. It has become.
[0006]
In the cooling operation power save mode, the control unit throttles the second auxiliary electronic expansion valve in accordance with the amount of power saving, while the first auxiliary electronic expansion valve has refrigerant in both the main path and the sub path. The aperture is controlled to flow.
[0007]
Further, the sub path is arranged below the main path.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention will be described with reference to the embodiment of the present invention shown in FIGS.
As shown in a diagram in which the refrigerant circuit diagram of FIG. 1 and the block diagram of the control system are mixed, 1 is a compressor that compresses refrigerant vapor including a discharge port 2, a suction port 3, and an accumulator 4. A four-way valve that switches the flow of refrigerant discharged from the discharge port 2 of the compressor 1 according to the operation mode, 6 is an indoor heat exchanger that is installed indoors and exchanges heat with the indoor air, and 7 passes through the refrigerant An electronic expansion valve 8 that can adjust the opening degree of the expansion, is installed outside the room, and heat exchange of the refrigerant with the outside air is performed, and the path is divided into an upper main path 9 and a lower sub path 10. A heat exchanger 11 is a first auxiliary electronic expansion valve capable of adjusting a throttle opening degree through which a refrigerant provided on the electronic expansion valve 7 side of the main path 9 passes and expands, and 12 a four-way valve 5 of the sub path 10. The throttle opening to which the refrigerant provided on the side passes and expands is adjusted. A possible second auxiliary electronic expansion valve, 13 is an outdoor temperature sensor comprising a thermistor provided in the vicinity of the outdoor heat exchanger 8, and 14 and 15 are inlets of the main path 9 on the first auxiliary electronic expansion valve 11 side. And a refrigerant temperature sensor comprising a thermistor provided at the inlet of the sub-pass 10 on the electronic expansion valve 7 side.
[0009]
Furthermore, 16 is the compressor 1, the four-way valve 5, the electronic expansion valve 7, the outdoor heat exchanger 8, the first auxiliary electronic expansion valve 11, the second auxiliary electronic expansion valve 12, and the outdoor temperature sensor 13. And the refrigerant temperature sensors 14 and 15 are stored in outdoor units, 17 is an indoor unit in which the indoor heat exchanger 6 is stored and installed indoors, and 18 and 19 are operating surfaces of the indoor unit 17. The operation mode selector switch that switches the operation mode such as heating / cooling of the air conditioner and the cooling operation power save mode that is the power saving operation at the time of cooling is selected by the user's operation provided in the illustration (not shown). A power save switch 20 is an indoor unit control unit that receives a switching signal between the operation mode switch 18 and the power save switch 19 and transmits a control signal to the outdoor unit control unit 21 described later. The control signal from the internal unit control unit 20 and the detected temperature data from the outdoor temperature sensor 13 and the refrigerant temperature sensors 14 and 15 are received, and the compressor 1 and the It is an outdoor unit control unit that controls the four-way valve 5, the electronic expansion valve 7, the first auxiliary electronic expansion valve 11, and the second auxiliary electronic expansion valve 12.
[0010]
Next, the operation and effect of the above configuration will be described.
First, the heating operation mode indicated by item number 1 in the explanatory diagrams of FIGS. 1 and 2 will be described.
When the user operates the operation mode changeover switch 18 to enter the heating operation mode, the indoor unit control unit 20 detects this and transmits a heating operation mode signal to the outdoor unit control unit 21.
When receiving the heating operation mode signal from the indoor unit control unit 20, the outdoor unit control unit 21 connects the four-way valve 5 to the discharge port 2 side of the compressor 1 and the outdoor heat exchanger 8, and It switches so that the suction inlet 3 side of the compressor 1 and the said indoor heat exchanger 6 may be connected, and the said compressor 1 is operated.
[0011]
The high-temperature and high-pressure refrigerant vapor discharged from the discharge port 2 of the compressor 1 passes through the four-way valve 5, dissipates heat to the indoor air in the indoor heat exchanger 6, and is condensed by heating to be high-temperature and high-pressure refrigerant. The high-temperature and high-pressure refrigerant liquid is squeezed and expanded by the electronic expansion valve 7 so that the temperature detected by the refrigerant temperature sensor 15, that is, the refrigerant temperature at the inlet of the sub-pass 10 is 0 ° C. or higher. A part of the low-temperature and low-pressure refrigerant liquid flows into the sub-pass 10 as it is, and the remaining part of the low-temperature and low-pressure refrigerant liquid is the temperature detected by the refrigerant temperature sensor 14, that is, the refrigerant temperature at the inlet of the main path 9. Is further throttled and expanded by the first auxiliary electronic expansion valve 11 so as to be lower than the outdoor temperature detected by the outdoor temperature sensor 13 and flows into the main path 9. When the outdoor temperature is a low temperature of 0 ° C. or lower, cold refrigerant below freezing point flows into the main path 9, and there is a possibility that the outdoor heat exchanger 8 may be frozen and freeze.
By flowing a refrigerant of 0 ° C. or higher through the sub-pass 10, it is possible to reduce frost and freezing on the outdoor heat exchanger 8.
Further, by arranging the sub path 10 below the main path 9, the entire outdoor heat exchanger 8 is effectively warmed, frosted and frozen by utilizing the upward convection of the heat of the sub path 10. Can be effectively prevented.
[0012]
Note that, by controlling the throttle amount of the second auxiliary electronic expansion valve 12, the refrigerant is controlled to flow through both the main path 9 and the sub path 10.
Further, whether or not the refrigerant is flowing through the main path 9 and the sub path 10 is detected based on the detected temperatures of the refrigerant temperature sensors 14 and 15.
The low-temperature and low-pressure refrigerant liquid flows into the main path 9 and the sub-path 10 of the outdoor heat exchanger 8 and absorbs heat from the outside air to evaporate into low-temperature and low-pressure refrigerant vapor. It returns to the suction port 3 of the compressor 1 through the four-way valve 5.
[0013]
Next, the cooling operation mode indicated by item number 2 in the explanatory diagrams of FIGS. 3 and 2 will be described.
When the user operates the operation mode changeover switch 18 to enter the cooling operation mode, the indoor unit control unit 20 detects this and transmits a cooling operation mode signal to the outdoor unit control unit 21.
When the outdoor unit control unit 21 receives a cooling operation mode signal from the indoor unit control unit 20, the outdoor unit control unit 21 connects the four-way valve 5 to the discharge port 2 side of the compressor 1 and the indoor heat exchanger 6, and It switches so that the suction inlet 3 side of the compressor 1 and the said outdoor heat exchanger 8 may be connected, and the said compressor 1 is operated.
[0014]
The high-temperature and high-pressure refrigerant vapor discharged from the discharge port 2 of the compressor 1 passes through the four-way valve 5, opens the first auxiliary electronic expansion valve 11, and reduces the throttle amount of the second auxiliary electronic expansion valve 12. By controlling, the refrigerant is controlled to flow through both the main path 9 and the sub-path 10, and is condensed by effectively dissipating heat to the outside air by the outdoor heat exchanger 8 through both paths. The high-temperature and high-pressure refrigerant liquid expands at the electronic expansion valve 7 to become a low-temperature and low-pressure refrigerant liquid, and the low-temperature and low-pressure refrigerant liquid flows into the indoor heat exchanger 6 and absorbs heat from the room air. The refrigerant vapor is cooled and evaporated to become a low-temperature and low-pressure refrigerant vapor, which passes through the four-way valve 5 and returns to the suction port 3 of the compressor 1.
[0015]
Since the main path 9 has a larger flow path resistance than the sub path 10, the first auxiliary electronic expansion valve 12 is opened and the second auxiliary electronic expansion valve 12 is opened. By controlling the throttle amount, the refrigerant can be controlled to flow through both the main path 9 and the sub path 10.
[0016]
Next, the cooling operation power save mode indicated by item number 3 in the explanatory diagrams of FIGS. 3 and 2 will be described.
When the user operates the operation mode changeover switch 18 and the power save switch 19 to enter the cooling operation power save mode, the indoor unit control unit 20 detects this and performs cooling to the outdoor unit control unit 21. Sends driving power save mode signal.
When the outdoor unit control unit 21 receives a cooling operation power save mode signal from the indoor unit control unit 20, the outdoor unit control unit 21 connects the four-way valve 5 to the discharge port 2 side of the compressor 1 and the indoor heat exchanger 6. Then, the compressor 1 is switched so as to be connected to the inlet 3 side of the compressor 1 and the outdoor heat exchanger 8 to cause the compressor 1 to perform a power saving operation.
[0017]
The high-temperature and high-pressure refrigerant vapor discharged from the discharge port 2 of the compressor 1 passes through the four-way valve 5, controls the throttle amount of the second auxiliary electronic expansion valve 12 according to the power saving amount, and the first By controlling the throttle amount of the auxiliary electronic expansion valve 11, the refrigerant flows in both the main path 9 and the sub path 10, and the inflow of the refrigerant to the sub path 10 is suppressed, and the outdoor heat exchanger 8 saves power. By appropriately radiating heat in accordance with the amount, it is appropriately condensed so as not to be overcooled and becomes a high-temperature and high-pressure refrigerant liquid, and the high-temperature and high-pressure refrigerant liquid is expanded by the electronic expansion valve 7 to thereby produce a low-temperature and low-pressure refrigerant. The low-temperature and low-pressure refrigerant liquid flows into the indoor heat exchanger 6 and absorbs heat from the indoor air to cool and evaporate into low-temperature and low-pressure refrigerant vapor. As Back said to the suction port 3 of the compressor 1.
[0018]
Whether or not the refrigerant is excessively cooled in the outdoor heat exchanger 8 can be determined based on the detected temperature of the refrigerant by the refrigerant temperature sensors 14 and 15.
[0019]
By using the outdoor temperature sensor 13 and the refrigerant temperature sensors 14 and 15 as thermistors, it is possible to provide an inexpensive configuration in which the types of components are unified.
[0020]
【The invention's effect】
As described above, according to the present invention, the outdoor heat exchanger is less likely to be frosted at a low outside air temperature of about 0 ° C. or less, and the air conditioner can efficiently perform a heating operation.
[Brief description of the drawings]
FIG. 1 is a diagram showing a refrigerant circuit diagram and a control block diagram of an embodiment of an air conditioner according to the present invention in a mixed state, and shows a heating operation state.
FIG. 2 is an explanatory diagram showing the contents of control of an embodiment of an air conditioner according to the present invention.
FIG. 3 is a diagram in which a refrigerant circuit diagram and a control block diagram of an embodiment of an air conditioner according to the present invention are mixedly shown, showing a cooling operation state.
FIG. 4 is a refrigerant circuit diagram of a conventional air conditioner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor 2 Discharge port 3 Suction port 5 Four-way valve 6 Indoor heat exchanger 7 Electronic expansion valve 8 Outdoor heat exchanger 9 Main path 10 Subpass 11 1st auxiliary electronic expansion valve 12 2nd auxiliary electronic expansion valve 13 Outdoor temperature sensor 14 15 Refrigerant temperature sensor 20 Indoor unit control unit 21 Outdoor unit control unit

Claims (4)

It has a heat pump refrigeration cycle that circulates refrigerant discharged from the discharge port of the compressor to the suction port of the compressor via the four-way valve, indoor heat exchanger, electronic expansion valve, outdoor heat exchanger, and the four-way valve. In the air conditioner
The path of the outdoor heat exchanger is divided into a main path and a sub path and connected in parallel, a first auxiliary electronic expansion valve is provided on the electronic expansion valve side of the main path, and a second auxiliary is provided on the four-way valve side of the sub path While providing an electronic expansion valve, an outdoor temperature sensor is provided in the vicinity of the outdoor heat exchanger, and a refrigerant temperature sensor is provided at an inlet of the main path on the first auxiliary electronic expansion valve side and an inlet of the sub path on the electronic expansion valve side. Providing a control unit for controlling the electronic expansion valve, the first auxiliary electronic expansion valve, and the second auxiliary electronic expansion valve in accordance with the detected temperature of these temperature sensors,
In the heating operation mode, the control unit throttles the electronic expansion valve so that the refrigerant temperature at the sub-pass inlet is 0 ° C. or higher, and the first auxiliary electronic expansion valve is used for the refrigerant temperature at the main-pass inlet is lower than the outdoor temperature. The air conditioner is characterized in that the second auxiliary electronic expansion valve is controlled so that the refrigerant flows in both the main path and the sub path. In the cooling operation mode, the control unit opens the first auxiliary electronic expansion valve, and controls the second auxiliary electronic expansion valve so that the refrigerant flows through both the main path and the sub path. The air conditioner according to claim 1. In the cooling operation power save mode, the control unit throttles the second auxiliary electronic expansion valve in accordance with the amount of power saving, while the first auxiliary electronic expansion valve flows through both the main path and the sub path. 2. The air conditioner according to claim 1, wherein the air conditioner is controlled to be throttled. The air conditioner according to claim 1, wherein the sub path is disposed below the main path.

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