JP3054560B2 - Air conditioner heating operation method - Google Patents

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 cooling and heating operation, and more particularly to a technology for safely performing a heating operation in an air conditioner having a refrigerant heating means used in a heating operation. .

[0002]

2. Description of the Related Art As this kind of technology, an air conditioner having a control unit for adjusting a heat input to a refrigerant heating means in accordance with a high-pressure side pressure, a low-pressure side pressure, or a temperature of a discharged gas refrigerant is disclosed in Japanese Patent Laid-Open No. Sho 54-1979. No. 15,550.

According to this air conditioner, the discharge pressure of the compressor 1 is guided from the pressure extracting section 23 to the pressure detector 24,
The control unit 25 compares and amplifies the pressure with the set pressure value, and adjusts the heat input to the refrigerant heater 10a according to the difference.
It is disclosed that abnormal pressure / temperature rise during heating operation can be prevented.

In the drawings, reference numeral 2 denotes a four-way switching valve, 3 denotes an outdoor heat exchanger, 4a denotes a pressure reducing mechanism, 6 denotes an indoor heat exchanger, 13 denotes an accumulator, 21 and 22 denote check valves, and 26 and 27 denote blowers. In addition, a broken line arrow indicates a refrigerant circuit during the cooling operation, and a solid line arrow indicates a refrigerant circuit during the heating operation.

[0005]

However, when the pressure of the refrigerant is high, the temperature of the refrigerant also tends to increase. However, in the air conditioner having the above structure, even if the pressure is measured, it is possible to know the refrigerant temperature at that time. On the contrary, even if the temperature is measured, the refrigerant pressure at that time cannot be known.

Therefore, in order to prevent both the pressure and the temperature from exceeding a predetermined temperature, it is necessary to measure each of them. In addition, since the pressure sensor is expensive, it is necessary to ensure the safety of the device by using an inexpensive temperature sensor.

[0007]

According to the present invention, there are provided a compressor, a flow passage , and the like as specific means for solving the above-mentioned problems of the prior art.
Switching valve mechanism, outdoor heat exchanger, decompressor, and indoor heat exchanger
A refrigerant circuit connected by refrigerant piping, and the indoor heat exchanger
Piping from the communication part with the pressure reducer to the suction port of the compressor
A refrigerant heating means connected and mounted for use during a heating operation, a refrigerant circuit for cooling to supply refrigerant discharged from the compressor by the flow path switching valve mechanism to an outdoor heat exchanger first, In an air conditioner configured to be able to selectively form a refrigerant circuit for heating to be supplied to the exchanger first,

[0008] A pipe whose upper end is closed is erected on a refrigerant pipe which is on the high pressure side during the heating operation, and a temperature sensor is connected to this pipe.
By providing a heating operation method of the air conditioner , wherein the heating operation by the heating means is stopped when the temperature in the pipe of the erected pipe reaches a predetermined temperature, An object of the present invention is to solve the above-described problem of the related art.

[0009]

[Action] The upper end of the high-pressure pipe during heating operation is closed and closed.
Inside the installed pipe, the high-pressure refrigerant discharged from the compressor is cooled by the outside air through the pipe wall and partially condensed, and is in a gas-liquid equilibrium state. The pressure in this part is estimated.

Therefore, the maximum withstand pressure specified for each device based on the wall thickness of the pipe, for example, 2.7 MPa (this is a pressure in consideration of a safety factor, and does not immediately burst at this pressure. If the temperature in the pipe reaches 65 ° C. corresponding to the same pressure), the heating operation by the refrigerant heating means is stopped, so that the pressure of the refrigerant circuit may rise abnormally beyond the specified maximum withstand pressure. As a result, there is no inconvenience that the refrigerant leaks due to cracks in the piping.

Further, since the pressure on the high pressure side can be estimated from the temperature of the refrigerant condensing by radiating heat to the low-temperature indoor air in the indoor heat exchanger, the heating operation by the refrigerant heating means is stopped based on this temperature. Even if it does so, the safety of the device is similarly ensured.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. In the air conditioner illustrated in FIG. 1, the refrigerant such as Freon, which is compressed and discharged by the compressor 1, switches the four-way switching valve 2 so that the outdoor heat exchanger 3, the capillary tube 4 serving as a pressure reducing means, and the reverse A refrigerant circuit for cooling operation, which is returned to the compressor 1 through the stop valve 5, the indoor heat exchanger 6, and the check valve 7, and is indicated by a broken line arrow, or the indoor heat exchanger 6, the first on-off valve 8, Any one of the refrigerant circuits for the heating operation, which is returned to the compressor 1 through the refrigerant heating heat exchanger 10 provided in the heating means 9 and is indicated by a solid arrow, is formed to be selectable, and the four-way switching valve 2 A pipe connecting the air conditioner and the indoor heat exchanger 6 is connected to a refrigerant inlet side of the compressor 1 by a second on-off valve 1.
1 and the orifice 12 are communicably connected.

The orifice 12 is provided with a gaseous refrigerant that has taken heat from room air having a relatively high temperature in the indoor heat exchanger 6 during the cooling operation to evaporate.
2 so that the flow rate of the refrigerant directly flowing back to the compressor 1 through the compressor 2 and the flow rate of the refrigerant flowing back to the compressor 1 through the four-way switching valve 2 and the check valve 7 are almost equal to each other. , Internal resistance is selected.

Reference numeral 14 denotes a flow control valve provided on a fuel supply pipe connected to the heating means 9 to control the flow rate of fuel, for example, gas, supplied to the heating means 9; It is an on-off valve connected in series.

Further, a part of the high-pressure refrigerant discharged from the compressor 1 is supplied to a piping section which becomes a high pressure side pipe during the heating operation, for example, a pipe connecting the four-way switching valve 2 and the indoor heat exchanger 6, to the heating operation. A pipe 16 having a length of, for example, 10 cm, whose upper end is closed, which can be cooled and condensed into the outside air at the time, that is, the outside air in winter through the pipe wall, and measures the temperature T1 in the pipe. And a temperature sensor 18 for measuring the temperature T2 of the refrigerant radiated and condensed by exchanging heat with indoor air having a low temperature in the indoor heat exchanger 6, and the temperature sensor 17 measures the temperature T2. Output temperature T
When 1 exceeds the first predetermined temperature or when the temperature T2 measured and output by the temperature sensor 18 exceeds the second predetermined temperature, the flow rate control valve 14 is fully closed and the refrigerant heating operation by the heating means 9 is performed. A controller 19 having a function of stopping is provided.

Since the temperature sensor 17 measures the temperature in the pipe where a part of the refrigerant is condensed as described above, the temperature sensor 17 has a complicated mechanism and does not require an expensive pressure sensor or the like.
From the temperature T1, the pressure on the high pressure side in the gas-liquid equilibrium state can be estimated.

Further, since the temperature sensor 18 also measures the temperature T2 of the refrigerant condensed by radiating heat to the room air as described above, the signal measured and output by the temperature sensor 18 also indicates the high-pressure side. The pressure can be estimated.

The heating operation by the air conditioner having the above configuration is as follows.
The control is performed by the controller 19 having required functions such as timekeeping, storage, calculation, and comparison, for example, as shown in the flowchart of FIG.

That is, the temperature of each part is measured by the temperature sensors 17 and 18, and the temperature T inside the pipe 16 is measured.
1 is the maximum withstand pressure of the equipment specified by the wall thickness of the pipe, etc.
For example, it is determined whether the temperature is equal to or lower than 65 ° C. corresponding to 2.7 MPa, or whether the temperature T2 in the indoor heat exchanger 6 is equal to or lower than 68 ° C. corresponding to the maximum withstand pressure of the device of 2.8 MPa. When both inequalities of ≦ 65 ° C. and T2 ≦ 68 ° C. are satisfied at the same time and the determination is YES, the process returns to the main control. When both or one of the inequalities is not satisfied, and when the determination is NO, the flow control valve 14 is fully closed to stop the heating operation by the heating means 9, warn that the pressure of the refrigerant circuit is abnormally rising by a buzzer (not shown), an electric sign or the like, and return to the main control.

Therefore, according to the heating operation by the air conditioner having the above structure, the heating operation of the heating means 9 is stopped when at least one of the temperature T1 in the pipe 16 or the temperature T2 in the indoor heat exchanger 6 exceeds a predetermined temperature. Therefore, there is no concern that the pressure on the high pressure side abnormally increases beyond the maximum withstand pressure specified for each device.

In the cooling operation of the air conditioner having the above-described structure, the refrigerant compressed and discharged by the compressor 1 is a refrigerant circuit for the cooling operation indicated by a broken arrow, that is, the outdoor heat exchanger 3, the capillary tube 4, This is performed by switching the four-way switching valve 2 so as to return to the compressor 1 via the check valve 5, the indoor heat exchanger 6, and the check valve 7.

In this case, all of the refrigerant that has passed through the check valve 5 flows into the indoor heat exchanger 6, and the refrigerant heating heat exchanger 1
The on-off valve 8 is closed so that it does not flow into zero. Also,
The on-off valve 11 is opened and operated so that almost half of the refrigerant discharged from the indoor heat exchanger 6 returns to the compressor 1 via the on-off valve 11 and the orifice 12 indicated by the dashed line arrow.

For this reason, the refrigerant having increased pressure and temperature discharged from the compressor 1 enters the outdoor heat exchanger 3 via the four-way switching valve 2 and the relative temperature supplied by a fan (not shown) Exchanges heat with low ambient air to condense. The liquid refrigerant that has radiated heat to the outside air and condensed is decompressed by the capillary tube 4 and flows into the indoor heat exchanger 6, where it takes away heat from the relatively high-temperature indoor air supplied by a fan (not shown) to remove indoor heat. It cools the air, evaporates itself, and is sucked and circulated by the compressor 1.

Since the present invention is not limited to the above embodiment, various modifications can be made without departing from the spirit of the present invention.

For example, only one of the temperature sensors 17 and 18 may be provided, and the heating operation of the heating means 9 may be stopped at the temperature T1 or the temperature T2.

Instead of the four-way switching valve 2, a flow path switching valve mechanism combining a plurality of on-off valves and the like may be used so that the flowing direction of the refrigerant can be appropriately switched as described above.

The heating means 9 and the refrigerant heating heat exchanger 10
Instead, an air conditioner having a so-called heat pump type heating-operable refrigerant circuit that sends the refrigerant radiated by the indoor heat exchanger 6 to the outdoor heat exchanger 3 and draws heat from the outside air may be used.

[0028]

As described above, according to the present invention, it is possible to prevent the pressure of the refrigerant circuit from abnormally increasing during the heating operation, so that there is a problem that the refrigerant leaks due to cracks in the piping. There is no concern to cause.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an air conditioner.

FIG. 2 is an explanatory diagram of one control example.

FIG. 3 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way switching valve 3 Outdoor heat exchanger 4 Capillary tube 5 First check valve 6 Indoor heat exchanger 7 Second check valve 8 On-off valve 9 Heating means 10 Refrigerant heating heat exchanger 11 On-off valve 12 Orifice 13 Accumulator 14 Flow control valve 15 On-off valve 16 Piping 17/18 Temperature sensor 19 Controller

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuya Sugiyama 2-5-1-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-5-149643 (JP, A) 56-173971 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 13/00 F24F 11/02

Claims (1)

(57) [Claims] 1. A compressor, a flow path switching valve mechanism, an outdoor heat exchanger,
Refrigerant circuit with decompressor and indoor heat exchanger connected by refrigerant piping
Channel and a communication section between the indoor heat exchanger and the pressure reducer.
A refrigerant heating means which is attached by piping connection to a suction port of a compressor and is used at the time of a heating operation;
In an air conditioner configured to be able to selectively form a cooling refrigerant circuit that first supplies a refrigerant discharged from a compressor to an outdoor heat exchanger by a mechanism and a heating refrigerant circuit that first supplies a refrigerant to an indoor heat exchanger. , Refrigerant piping that is on the high pressure side during heating operation
Temperature of the pipe together with the upper end portion is erected piping occluded
A heating operation method for an air conditioner , comprising: providing a temperature sensor; and stopping a heating operation by the heating means when a temperature inside the pipe of the erected pipe reaches a predetermined temperature.