JPH0218461Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a refrigerant circuit that processes surplus refrigerant during heating and cooling operations.

[Prior art]

As an expansion mechanism of an air conditioner capable of cooling/heating operation, a capillary tube is generally used in small household room air conditioners. However,
Use a compressor with capacity control,
In cases where the range of operating conditions is wide, capillary control is not sufficient, and an automatic temperature expansion valve or an electric expansion valve operated by an electric signal is used to control the superheat of the refrigerant sucked into the compressor. It is widely adopted.

When superheating the refrigerant sucked into the compressor, if there is excess refrigerant in the refrigerant system than is necessary for proper system operation, this excess will accumulate in the condenser and condense. This causes pressure to rise, resulting in inefficient operation. Also,
If there is a large amount of surplus refrigerant, the pressure will be abnormally high, leading to a situation where operation becomes impossible. To prevent this, it is necessary to provide a liquid receiver at the condenser outlet.

An example of a conventional refrigerant circuit is shown and explained in FIGS. 1 and 2. First, in FIG. 1, 1 is a compressor, 2 is a four-way valve connected to this compressor 1, and 3 is this four-way valve 2. 4 is a reversible expansion valve, 5 is an indoor heat exchanger connected to the four-way valve 2, and 6 is an accumulator, which are connected in sequence to form a refrigerant circuit. There is.

Since the operation of the refrigerant circuit configured in this way is generally well known, a detailed explanation thereof will be omitted.During cooling operation, the outdoor heat exchanger 3 acts as a condenser, and during heating operation, the indoor heat exchanger 3 acts as a condenser. 5 acts as a condenser, liquid receivers 7a and 7b are installed at these outlets, that is, before and after the reversible expansion valve 4. This has the advantage of being able to store excess refrigerant during both cooling and heating, but
There is a disadvantage that two liquid receivers are required, making the configuration complicated and uneconomical.

Next, in FIG. 2, the same symbols as in FIG. 1 indicate corresponding parts, 7 is a liquid receiver, 8a, 8b,
8c and 8d are check valves, and each of these check valves 8a to 8
d constitutes a bridge circuit.

In the circuit shown in Fig. 2, the number of liquid receivers can be reduced to one, but four check valves are required, and the reliability of the refrigerant circuit is impaired due to clogging of the check valves 8a to 8d. It has the disadvantage of being exposed.

[Summary of the idea]

In view of the above points, the present invention was devised to solve these problems and eliminate such drawbacks.The purpose of this invention is to create a simple circuit configuration with only one liquid receiver without using a check valve. The purpose of the present invention is to provide a refrigerant circuit that stores surplus refrigerant in both heating and cooling cycles and can operate efficiently.

In order to achieve this object, the present invention connects a refrigerant container with a capillary tube to its inlet and outlet so as to be parallel to the reversible expansion valve.

[Example of idea]

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 3 is a block diagram showing one embodiment of the refrigerant circuit according to the present invention.

In FIG. 3, the same parts as in FIGS. 1 and 2 are designated by the same reference numerals, and their explanation will be omitted.

9a and 9b are capillary tubes connected to the liquid receiver 7;
The liquid receiver 7 equipped with the capillary tubes 9a and 9b is connected to the inlet and outlet in parallel with the reversible expansion valve 4. 10
is a refrigerant pipe that connects the indoor unit and the outdoor unit, and this refrigerant pipe 10 may be configured, for example, depending on the installation conditions of the air conditioner.
In some cases 5m is sufficient, in others 30m is necessary.

FIG. 4 is a detailed diagram showing a portion related to the liquid receiving part in the embodiment shown in FIG. 3.

An inlet/outlet tube 11 is connected in series to the capillary tubes 9a and 9b.
a, 11b are connected, and inside the liquid receiver 7, the openings of the inlet/outlet pipes 11a, 11b are arranged close to each other and facing each other.

Figure 5 shows the characteristics showing changes in the amount of refrigerant required for the system due to changes in refrigerant piping length, with the horizontal axis representing the refrigerant piping length L (m) and the vertical axis representing the refrigerant amount LQ (Kg) required for the system. In the figure, H indicates heating characteristics, and C indicates cooling characteristics.

As is clear from Fig. 5, whether surplus refrigerant is generated during cooling operation or heating operation depends on the installation conditions of the air conditioner; A receiver that can absorb excess refrigerant is required.

Next, the operation of the embodiment shown in FIG. 3 will be explained.

First, the pressure in the liquid receiver 7 corresponds to an intermediate pressure that is reduced from high pressure to low pressure by the expansion valve 4, and the amount of refrigerant stored in the liquid receiver 7 changes depending on the dryness of the refrigerant in this state. In other words, if the amount of refrigerant is too large, the degree of supercooling at the condenser outlet will increase,
The pressure is reduced in the inlet capillary tubes 9a and 9b, and no flash gas is generated in the refrigerant entering the liquid receiver 7, which acts to store a large amount of liquid refrigerant in the liquid receiver 7.

Next, when the amount of refrigerant is appropriate and the degree of supercooling is reduced, the pressure is reduced in the inlet capillary tubes 9a and 9b, and flash gas is generated in the refrigerant entering the liquid receiver 7, the refrigerant gas accumulates in the upper part of the liquid receiver 7, and the Maintain a liquid level.
(See Figure 4) Furthermore, since the inlet and outlet pipes 11a and 11b of the liquid receiver 7 are arranged close to each other and facing each other inside the liquid receiver 7, surplus refrigerant can be stored regardless of the direction in which the refrigerant flows. Can be done. According to the inventor's experiments, good results were obtained when the distance between the openings of the inlet and outlet tubes 11a and 11b was set to about 0.5 to 1.0 times the inner diameter of the inlet and outlet tubes 11a and 11b.

In this way, it is possible to use only one liquid receiver without using a check valve, and to store surplus refrigerant in both the cooling and heating cycles, thereby achieving efficient operation.

[Efficiency of ideas]

As is clear from the above explanation, according to the present invention, a single liquid receiver is used, and the liquid receiver is installed at the entrance and exit in parallel with the reversible expansion valve, without using complicated means such as a check valve. With a simple circuit configuration that connects refrigerant containers equipped with capillary tubes, it is possible to create a refrigerant circuit that stores excess refrigerant during both heating and cooling cycles and can operate efficiently, so the practical effects are extremely large. It is. Further, it is extremely effective in that the cost can be reduced by simplifying the configuration.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing an example of a conventional refrigerant circuit, FIG. 3 is a block diagram showing an embodiment of the refrigerant circuit according to the present invention, and FIG. 4 is a liquid receiver in the embodiment of FIG. 3. FIG. 5 is a detailed diagram showing extracted parts related to the device, and FIG. 5 is a characteristic diagram showing changes in the amount of refrigerant required for the system due to changes in the refrigerant piping length, which is used to explain the operation of FIG. 3. 1...Compressor, 2...Four-way valve, 3...Outdoor heat exchanger, 4...Reversible expansion valve, 5...Indoor heat exchanger, 7...Liquid receiver, 9a, 9b...Capillary tube, 11
a, 11b... Inlet/outlet pipe.

Claims (1)

[Claims for Utility Model Registration] A compressor, a four-way valve, an outdoor heat exchanger, a reversible expansion valve, and an indoor heat exchanger are connected in sequence, and a capillary tube is provided at the entrance and exit so as to be parallel to the reversible expansion valve. A refrigerant circuit configured by connecting refrigerant containers, wherein openings of inlet and outlet pipes connected in series to a capillary tube inside the refrigerant container are arranged close to each other and facing each other. circuit.