JPH06281201A - Air conditioner - Google Patents

Abstract

PURPOSE:To perform a sure prevention of freezing of drain water and to effect an efficient and sure defrosting in an outdoor heat exchanger by a method wherein there is provided a heater having a positive characteristic for preventing the freezing of drain water generated at the outdoor heat exchanger. CONSTITUTION:In performing a heating operation, drain water generated at an outdoor heat exchanger 16 is accumulate at a drain pan 21, the accumulated drain water is discharged from a water discharging port 22 out to an outdoor device 20. At this time, the drain water accumulated at the drain pan 21 is cooled and frozen with surrounding air in winter season. However, freezing of the drain water can be surely prevented by heating it with a semiconductor heater 12 of positive characteristic in which its heating calorie can be increased or decreased in response to a degree of temperature of surrounding atmosphere. In addition, frost adhered at a lower part of the outdoor heat exchanger 16 is defrosted with the semiconductor heater 12 of positive characteristic in concurrent with a defrosting operation, thereby a defrosting time can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for preventing freezing of drain water generated in an outdoor heat exchanger during heating operation.

[0002]

2. Description of the Related Art Conventionally, an air conditioner of this type, for example, the one disclosed in Japanese Utility Model Publication No. 4-72139 is known, and this air conditioner includes a compressor (compressor), a four-way valve, An outdoor heat exchanger, a parallel circuit consisting of an on-off valve that is opened only during cooling operation, and a heating decompression device, a cooling / heating decompression device, and an indoor heat exchanger are connected in a ring, and heating is provided below the outdoor heat exchanger. An outdoor drain pan for receiving drain water generated by the outdoor heat exchanger during operation is arranged, and the outdoor drain pan is provided with a heater through which the refrigerant that has passed through the cooling / heating decompression device flows during heating operation. .

In the air conditioner configured as described above, during heating operation, a medium-temperature / intermediate-pressure refrigerant that has been decompressed by the cooling / heating decompression device is caused to flow through the heating heater, and this heat causes drain water collected in the outdoor drain pan. Since it heats the drain water, the amount of heat required to prevent the freezing of this drain water is reduced to reduce heat loss, and the decrease in the condensation action of the refrigerant in the indoor heat exchanger is suppressed to a low level, preventing a large decrease in heating capacity. It was

[0004]

However, in the air conditioner configured as described above, the refrigerant used for the heating operation and the refrigerant used for the freeze prevention of the drain water are separated, and the heating / cooling decompression device is also used. By flowing a medium-temperature and medium-pressure refrigerant that has been decompressed by, heat the drain water accumulated in the outdoor drain pan with this heat to prevent freezing of this drain water, so when the outside air temperature is below freezing, There is a problem that the freezing of the drain water cannot be prevented only by the heating value of the heater.

In order to solve the above-mentioned problems, there is also an outdoor drain pan provided with a nichrome wire heater in the lower part. In this case, the drain water collected in the outdoor drain pan by the nichrome wire heater is provided. Although it is possible to prevent the freezing of the drainage water, since the heating value of the nichrome wire heater hardly changes with the change of the outside air temperature, if the outside air temperature is lowered by simply providing the above nichrome wire heater, the drain water freezes. There is a problem that it is not possible to obtain a sufficient amount of heat generation (amount of heat) to prevent the above.

The air conditioner of the present invention solves the above problems and provides an air conditioner capable of reliably preventing freezing of drain water and efficiently defrosting. It is intended to be provided.

[0007]

In order to achieve the above object, the air conditioner of the present invention is provided with a refrigeration cycle having a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger and the like. The air conditioner is provided with a positive temperature characteristic heater for preventing freezing of the drain water generated in the outdoor heat exchanger.

[0008]

With the above structure, when the outside air temperature decreases during the heating operation, the heat generation amount of the positive characteristic heater increases in accordance with the decrease of the outside air temperature, and the heat generation amount of the positive characteristic heater increases. It is possible to reliably prevent the drain water from freezing by heating the drain water that is frozen by the heater. Moreover, when the above-mentioned positive characteristic heater is used at the same time as the defrosting operation, the positive characteristic is reduced according to the decrease in the outside air temperature. Since the amount of heat generated by the heater increases, it is possible to efficiently and reliably defrost the frost that forms on the outdoor heat exchanger.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the air conditioner of the present invention is shown in FIG.
It will be described in detail with reference to FIG.

The electric circuit of the air conditioner of the present invention is constructed as shown in FIG. 1. In FIG. 1, an AC power source 1, a main switch 2, a temperature sensor 3, and a compressor 4 are provided.
Are connected in series, and a series circuit of the outdoor fan motor 5 and the relay switch 6 is connected in parallel to a series circuit of the temperature sensor 3 and the compressor 4, and a series circuit of the outdoor fan motor 5 and the relay switch 6 is connected. Further, a series circuit of the cooling / heating operation changeover switch 7, the pressure reducing device (capillary tube) 8 and the relay switch 9 is connected in parallel.

The decompression device 8 and the relay switch 9
The temperature sensor 10 and the relay 11 are connected in parallel to the series circuit of the temperature sensor 10 and the relay 11, the positive temperature characteristic semiconductor heater 12 is connected in parallel to the series circuit of the temperature sensor 10 and the relay 11, and the cooling / heating operation changeover switch 7 is connected. The series circuit of the indoor fan motor 13 and the relay switch 14 is connected in parallel to the series circuit of the pressure reducing device 8 and the relay switch 9.

FIG. 2 is an explanatory view of a refrigeration cycle of an embodiment of the air conditioner of the present invention. In FIG. 2, the compressor 4, the four-way valve 15, the outdoor heat exchanger 16, the pressure reducing device 8, the indoor heat exchanger are shown. 17 are sequentially connected in an annular shape by a refrigerant pipe, and the positive characteristic semiconductor heater 12 is provided near the outdoor heat exchanger 16 or the like.
An outdoor fan 18 for blowing outside air to the outdoor heat exchanger 16 in the vicinity of the outdoor heat exchanger 16, and the indoor heat exchanger 1
An indoor fan 19 that blows the air, which has been heat-exchanged by the indoor heat exchanger 17, into the room is provided in the vicinity of 7.

FIG. 3 is a sectional view of the main part of the outdoor unit of FIG.
In FIG. 3, the outdoor unit 20 includes an outdoor heat exchanger 16, a drain pan 21 below the outdoor heat exchanger 16 for receiving drain water produced by the outdoor heat exchanger 16, and a drain pan 21 for drain water. A drain port 22 for draining the outside of the outdoor unit 20 and a positive temperature characteristic semiconductor heater 12 for preventing the drain water generated in the outdoor heat exchanger 16 from being frozen by the outside air in the lower part of the drain pan 21. ing.

The characteristics of the resistance value of the positive temperature characteristic semiconductor heater used in the air conditioner of the present invention and the conventional nichrome wire heater depending on the outside air temperature are as shown in FIG.
In the positive characteristic semiconductor heater A, the resistance value of the positive characteristic semiconductor heater A decreases as the outside air temperature decreases, and the amount of heat generation increases in accordance with the decrease. The resistance value of the nichrome wire heater B is hardly changed even when the outside air temperature is lowered, and therefore, the heat generation amount is also hardly changed.

The defrosting state of the air conditioner provided with the positive temperature coefficient semiconductor heater of the present invention and the conventional air conditioner provided with the nichrome wire heater is as shown in FIG. That is, in the case of using the positive characteristic semiconductor heater A, the heat generation amount of the positive characteristic semiconductor heater A increases in accordance with the decrease in the outside air temperature, so that the heating amount necessary for defrosting can be sufficiently obtained. In the case of using the nichrome wire heater B, the calorific value is hardly changed even when the outside air temperature is lowered, a sufficient heating amount required for defrosting cannot be obtained, and a large difference occurs in defrosting completion time.

Next, the operation of the air conditioner of the present invention having the above structure will be described.

First, when the main switch 2 is turned on,
The temperature sensor 3 and the compressor 4 are energized to operate the air conditioner, and the temperature sensor 3 adjusts the indoor temperature to control the operation of the compressor 4. Further, when the cooling / heating operation changeover switch 7 is turned on, the positive characteristic semiconductor heater 12 is energized, and at the same time, the relay 11 is energized via the temperature sensor 10 which detects the outside air temperature and turns it off when the temperature falls below a predetermined temperature. When 11 is energized, the relay switches 6, 9 and 14 are turned on to energize the outdoor fan motor 5, the pressure reducing device 8 and the indoor fan motor 13, and when the relay switch 9 is turned on, the four-way valve 15 is energized. Then, when the four-way valve 15 is energized, the flow of the refrigerant changes, and the heating operation for the room is performed.

When the heating operation is performed in the above case, the drain water generated in the outdoor heat exchanger 16 is collected in the drain pan 17, and the collected drain water is drained to the outside of the outdoor unit 20 through the drain port 22. At this time, the drain water collected in the drain pan 17 is cooled by the outside air and freezes in the winter, but the amount of heat generated by the positive temperature characteristic semiconductor heater 12 decreases due to the temperature of the outside air. It is reliably prevented by heating with the semiconductor heater 12.

For example, when the outside air temperature is about 10 ° C. in early winter, the small amount of heat generated by the positive temperature characteristic semiconductor heater 12 prevents the drain water from freezing and is drained to the drain port 22. Further, when the temperature is extremely cold in the midwinter (below freezing point), the large amount of heat generated by the positive temperature characteristic semiconductor heater 12 reliably prevents freezing of the drain water, and the drain water is discharged to the drain port 22.

Moreover, when the heating operation is performed, frost forms on the lower part of the outdoor heat exchanger 16, the heating operation is temporarily stopped, and the four-way valve 19 reverses the flow of the refrigerant to cause the outdoor heat exchanger 16 to operate. Defrosting operation for removing the frost that forms on the lower part of the frost, and defrosting the frost that forms on the lower part of the outdoor heat exchanger 16 by the positive characteristic semiconductor heater 12 at the same time as this defrosting operation,
The defrosting time can be shortened.

Instead of the above-mentioned positive-characteristic semiconductor heater 12, a positive-characteristic thermistor or the like having the same effect may be used.

[0022]

As described above, the air conditioner of the present invention is provided with the positive temperature characteristic heater for preventing the freezing of the drain water generated in the outdoor heat exchanger, so that the positive temperature characteristic heater responds to the decrease in the outside air temperature. The amount of heat generated by the positive characteristic heater increases, and the amount of heat generated by the positive characteristic heater increases. Therefore, the drain water that is frozen by the positive characteristic heater can be heated to reliably prevent the freezing of the drain water. If the positive characteristic heater is used at the same time as the frost operation, the amount of heat generated by the positive characteristic heater increases in accordance with the decrease in the outside air temperature. Therefore, the defrosting of the frost that forms on the outdoor heat exchanger can be performed efficiently and reliably. You can

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of an air conditioner of the present invention.

FIG. 2 is an explanatory diagram of a refrigeration cycle showing an embodiment of the air conditioner of the present invention.

FIG. 3 is a cross-sectional view of main parts of an outdoor unit showing an embodiment of the air conditioner of the present invention.

FIG. 4 is a characteristic diagram of resistance values of a positive temperature characteristic semiconductor heater and a conventional heater according to an outside air temperature showing an embodiment of an air conditioner of the present invention.

FIG. 5 is an explanatory diagram of a defrosting state of a positive temperature characteristic semiconductor heater and a conventional heater showing an embodiment of the air conditioner of the present invention.

[Explanation of symbols]

 4 Compressor 8 Pressure reducing device 12 Positive characteristic semiconductor heater 15 Four-way valve 16 Outdoor heat exchanger 17 Indoor heat exchanger

Claims (1)

[Claims] 1. An air conditioner provided with a refrigeration cycle including a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, etc., wherein freezing of drain water generated by the outdoor heat exchanger is performed. An air conditioner characterized by being provided with a positive characteristic heater for preventing it.