JPH0222602Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to an improvement of a heat pump type air conditioner configured by providing an expansion valve and a branch circuit for the expansion valve.

[Technical background of the invention and its problems]

In a heat pump type air conditioner, a unidirectional expansion valve is arranged between the indoor heat exchanger and the outdoor heat exchanger, and the flow direction of the refrigerant at the expansion valve is set indoors. A refrigeration cycle that is equipped with a branch circuit to keep the refrigerant discharged from both the inner heat exchanger side and the outdoor heat exchanger side constant, and can perform cooling or heating operation using the same expansion valve. There is.

Conventionally, as shown in Fig. 1, a branch circuit of such an air conditioner has four check valves b arranged around a one-way expansion valve a, and these check valves b...
A circuit is used in which the refrigerant flowing from the outdoor heat exchanger c is connected to the bridge in the flow direction of the expansion valve a, using the flow characteristics of each check valve b... The refrigerant flows through the expansion valve a to the indoor heat exchanger d, and the refrigerant flowing from the indoor heat exchanger d is divided so as to flow through the expansion valve a to the outdoor heat exchanger c, as shown by the dashed arrow. A refrigeration cycle capable of cooling and heating is constructed using the flow of these different refrigerants.

By the way, it is known that in a heat pump type air conditioner capable of cooling and heating, the amount of refrigerant circulated in the refrigeration cycle is different between cooling operation and heating operation. This has traditionally been adopted as a measure to suppress the decline in heating capacity, and usually involves a large amount of refrigerant being circulated during cooling, and a smaller amount during heating.

However, in the branch circuit using the above-mentioned check valves b..., the pressure reduction resistance is constant for both cooling and heating. For this reason, the branch circuit alone cannot reduce the pressure in accordance with the amount of refrigerant circulated, and has the disadvantage that it is difficult to construct a refrigeration cycle.

[Purpose of invention]

This invention was made with attention to the above-mentioned circumstances, and its purpose is to provide a heat pump type air conditioner that can easily configure a refrigeration cycle for cooling and heating using a shunt circuit. It is in.

(Structure of the invention) This invention replaces some of the check valves that make up the shunt circuit with capillary tubes, and configures the shunt circuit to have a difference in pressure reduction resistance between heating and cooling. The objective is to make it possible to easily configure a refrigeration cycle according to the different refrigerant circulation amounts using the refrigerant.

[Example of idea]

This invention will be explained below based on an embodiment shown in FIGS. 2 and 3. Figure 2 shows a heat pump type air conditioner, in which 1 is a compressor, 2
is a four-way valve for switching between cooling and heating, 3 is an outdoor heat exchanger, and 4 is an indoor heat exchanger. Each of these devices is sequentially connected through a refrigerant path 5. Further, an expansion valve 6 having a unidirectional flow characteristic is provided between the outdoor heat exchanger 3 and the indoor heat exchanger 4. A branch circuit 7 that guides refrigerant in a fixed direction is provided, and constitutes a refrigeration cycle 8 capable of cooling and heating operations.

On the other hand, the structure of the branch circuit 7, which is the main part of this invention, is such that a first flow path 9a is provided across the inlet and outlet sides of the expansion valve 6, and the first
At each end of the flow path 9a, a pair of second
A flow path system is formed by disposing flow paths 9b, 9b and third flow paths 9c, 9c, respectively. And each second
flow paths 9b, 9b and third flow paths 9c, 9c
During cooling, the refrigerant flowing from the outdoor heat exchanger 3 flows through the expansion valve 6 to the indoor heat exchanger 4, and during heating, the refrigerant flowing from the indoor heat exchanger 4 flows through the expansion valve 6 to the outdoor heat exchanger 4. Four check valves 10...and one of the check valves 10 is inserted into the bridge instead of the capillary tube 11 so that the flow can flow to the capillary tube 11. Here, to explain the area around the capillary tube 11, this refers to a line through which the refrigerant flows only during heating, for example, a line in which the refrigerant flows, for example, the third flow path 9c which is upstream of the expansion valve 6, and the capillary tube 11 is It is inserted in place of a check valve, and by installing it in this specified location, a resistance circuit with a high resistance in which the capillary tube 11 and the expansion valve 6 are connected in series is installed during heating, and a resistance circuit with a high resistance is connected in series between the capillary tube 11 and the expansion valve 6 during cooling. The tube 11 and the expansion valve 6 each form a low resistance resistance circuit connected in parallel. However, by replacing the capillary tube 11, the shunt circuit 7 is configured to create a difference in pressure reduction resistance between heating and cooling.

Therefore, when performing heating using the heat pump type air conditioner configured in this way, by switching the four-way valve 2 to the heating side and operating the compressor 1, the compressor 1, the four-way valve 2, and the room A heating cycle is configured in which the refrigerant flows through the inner heat exchanger 4, the branch circuit 7, the expansion valve 6, and the outdoor heat exchanger 3 in this order. Here, the refrigerant flowing through the branch circuit 7 is as follows:
Capillary tube 11, expansion valve 6 second flow path 9
The air flows through the check valve 10 located on the upper side of the air, and is greatly reduced in pressure due to the formation of a series circuit as shown in FIG. In this way, a throttling capacity corresponding to the amount of refrigerant circulation can be obtained.

In addition, when performing air conditioning, by switching the four-way valve 2 to the cooling side and operating the compressor 1, the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the branch circuit 7, the expansion valve 6, and the indoor A cooling cycle is configured in which the refrigerant flows through the inner heat exchanger 4 in sequence. Here, the refrigerant flowing through the branch circuit 7 flows through the capillary tube 11 and the expansion valve, respectively, and a parallel circuit is formed by connecting the capillary tube 11 and the expansion valve 6 in parallel as shown in FIG. Based on this, the pressure will be reduced slightly. In this way, a throttling capacity corresponding to the amount of refrigerant circulation can be obtained.

In FIG. 2, solid line arrows indicate the flow of refrigerant during cooling, and broken line arrows indicate the flow of refrigerant during heating.

Therefore, by replacing some of the check valves 10 of the shunt circuit 7 with capillary tubes 11 to create a difference in pressure reduction resistance between cooling and heating, it is possible to use only the shunt circuit 7. It becomes possible to perform throttling according to the amount of refrigerant circulation, and it becomes possible to easily and easily construct a heat pump type refrigeration cycle, which was conventionally considered difficult to construct. Moreover, the capillary tube 11 not only makes a difference in pressure reduction resistance, but also serves the high pressure side of the refrigeration cycle (the discharge side of the compressor 1) bordering on the expansion valve 6.
Since it has a function to bypass the low pressure side (the suction side of the compressor 1), it is possible to obtain a gas balance with no pressure difference through the capillary tube 11 when the air conditioner is stopped, resulting in a good gas balance. It is possible to obtain gas balance in the refrigeration cycle. The gas balance characteristics at this time are shown in FIG. However, the dashed-dotted line indicates gas balance A in an air conditioner that does not use a conventional capillary tube, and the solid line indicates gas balance B in an air conditioner that uses the capillary tube of this invention. It will be recognized from the comparison of gas balance B that good gas balance characteristics can be obtained. However, it also has the advantage of making it easier to restart the air conditioner (both cooling and heating), which is considered to be a problem. In addition, capillary tube 11
By using this, it is possible to eliminate a part of the expensive check valves 10, which has the advantage of reducing costs.

In the above-mentioned embodiment, the check valve in the third flow path through which the refrigerant flows during heating is replaced with a capillary tube among the check valves constituting the shunt circuit. The same effect can be obtained even if the check valve of the second flow path through which the refrigerant flows is replaced with a capillary tube.

[Effect of idea]

As explained above, according to this invention, some of the check valves connected by bridges constituting the shunt circuit are replaced with capillary tubes to create a difference in pressure reduction resistance between heating and cooling. With this configuration, it is now possible to perform throttling control corresponding to the different refrigerant circulation amounts during heating and cooling using only the shunt circuit. A refrigeration cycle can be constructed. Moreover, the capillary tube not only forms pressure reduction resistance, but also uses the bypass function of the capillary tube to maintain a good gas balance in the refrigeration cycle when the air conditioner is stopped, making restarting easier. There are also benefits that can be achieved. Furthermore, by using a capillary tube, some expensive check valves can be eliminated, resulting in cost advantages.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional heat pump type air conditioner, Figs. 2 to 5 show an embodiment of this invention, Fig. 2 is a block diagram showing a heat pump type air conditioner, and Fig. 3 is a block diagram showing a conventional heat pump type air conditioner. 4 is a circuit diagram extracting and showing the flow of refrigerant to the capillary tube and expansion valve during heating, FIG. 4 is a circuit diagram extracting and showing the flow of refrigerant to the capillary tube and expansion valve during cooling, and FIG. The figure is a diagram showing the gas balance of the refrigeration cycle when the air conditioner is stopped in comparison with the conventional gas balance. 3...Outdoor heat exchanger, 4...Indoor heat exchanger, 6...Expansion valve, 7...Diversion circuit, 9b, 9c
...Flow path, 10...Check valve, 11, 20...Capillary tube.

Claims (1)

[Scope of utility model registration request] A pair of flow channels connected in parallel to the indoor heat exchanger and the outdoor heat exchanger are provided on the inlet side and the outlet side of the unidirectional expansion valve, respectively, and a check valve is provided in each of these flow channels, The heat pump type air is configured to form a bridge-like branch circuit, and allows refrigerant to flow from both the indoor heat exchanger and the outdoor heat exchanger to the expansion valve in accordance with the flow direction of the expansion valve. In the harmonizing device, among the check valves constituting the branch circuit, the check valve in the flow path through which the refrigerant flows only during heating is replaced with a capillary tube, and the expansion valve and the capillary tube are connected in series during heating. 1. A heat pump type air conditioner, wherein a resistance circuit is formed by connecting the expansion valve and the capillary tube in parallel during cooling.