JPH0539969A - Condenser for refrigerant - Google Patents

Abstract

PURPOSE:To obtain the title condenser whereby against a load, the degree of subcooling most suitable for the efficiency of a refrigeration cycle can be realized. CONSTITUTION:On the upper side of core parts, at which a plurality of flat tubes 2 forming pathways for a refrigerant and corrugated fins 3 are alternately stacked in vertical direction, a receiving tube 4 with a large content volume is placed between the core parts. Headers 5, 6 are respectively joined to both end parts of each of the flat tubes 2 and the receiving tube 4, and the flat tubes 2 and the receiving tube 4 communicate with each other through the headers 5, 6. The receiving tube 4 acts as a receiver and the flat tubes 2 on the downstream side of the receiving tube 4 act as a cooler for subcooling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant condenser used in a refrigeration cycle of a vehicle air conditioner.

[0002]

2. Description of the Related Art In a refrigeration cycle used in an air conditioner for passenger cars, a receiver is installed downstream of a refrigerant condenser to maintain a subcool (supercooling degree) at 0 ° C. However, since the efficiency (COP) of the refrigeration cycle is better to be subcooled, in a bus air conditioner, a supercooler (heat exchanger for subcooling) is installed downstream of the receiver. Have a degree.

[0003]

In contrast to the receiver cycle described above, in a cycle without a receiver, when the same load is applied, the cycle balance on the Mollier diagram becomes larger as the refrigerant charge amount increases. 4 changes from the position indicated by the solid line to the position indicated by the broken line and the position indicated by the alternate long and short dash line,
Supercooling also increases.

At that time, as shown in FIG. 5, it can be seen that the cycle efficiency shows a maximum value (called optimum degree of supercooling) at a certain degree of supercooling. When this is changed and the experiment is carried out,
It was found that the higher the load (the higher the flow rate), the greater the optimum degree of subcooling. That is, the higher the load, the larger the amount of refrigerant to be charged. However, in the conventional refrigeration cycle used for the air conditioner for a bath, since the size of the supercooler is constant, the change in the supercooling degree with respect to the load change is small, and it cannot be said to be very efficient.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a refrigerant condenser capable of realizing a degree of supercooling having the highest cycle efficiency with respect to a load. ..

[0006]

In order to achieve the above object, the present invention provides a refrigerant condenser for condensing and liquefying a high-temperature, high-pressure gas-phase refrigerant flowing in the refrigerant passage by heat exchange with air. The technical means is to insert a tube with a large internal volume in the middle of the process.

[0007]

In the refrigerant condenser of the present invention having the above-described structure, the gas-liquid two-phase refrigerant liquefied to a certain degree of dryness by heat exchange with air flows into the tube having a large internal volume in the middle of the refrigerant passage. The refrigerant passing through the tube has a large internal volume of the tube and therefore hardly condenses, and flows out of the tube in a state of almost the same dryness as the tube inlet. Then, the refrigerant flowing out of the tube is completely liquefied when passing through the refrigerant passage downstream of the tube, is further supercooled and flows out of the refrigerant condenser.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the refrigerant condenser of the present invention is shown in FIG.
Also, description will be made with reference to FIG. FIG. 1 is an overall view of a refrigerant condenser. The refrigerant condenser 1 of the present embodiment is applied to a refrigeration cycle having no receiver, and includes a core portion formed by vertically stacking a plurality of flat tubes 2 and corrugated fins 3, and an upper stage of the core portion. It is composed of a receiver tube 4 (tube of the present invention) interposed on the side, and headers 5 and 6 connected to both ends of each flat tube 2 and the receiver tube 4. The flat tube 2 has a refrigerant passage formed therein and communicates with the headers 5 and 6 at both ends.

Inside the headers 5 and 6, partition walls 7, 8 and 9 for making a U-turn of the refrigerant flowing through the core portion are provided. A partition wall 7 provided on one header 5 (on the left side in FIG. 1) is arranged so as to partition between the receiver tube 4 and the flat tube 2 located below the receiver tube 4.
The partition walls 8 and 9 provided on the other header 6 are arranged between the receiver tube 4 and the flat tube 2 located above the receiver tube 4, and at a substantially middle portion of the header 6. Further, the other header 6 is provided with a coolant inlet 10 and a coolant outlet 11 at its lower and upper portions.

Therefore, the refrigerant flowing from the inlet 10 is
As shown by the solid line arrow in FIG. 1, after flowing through the core portion while making a U-turn in each header, it flows out from the outlet 11.

The receiver tube 4 is provided in the same length as the flat tube 2, and its cross-sectional area is equal to that of the flat tube 2.
It is set much larger than the cross-sectional area of the passage. The receiver tube 4 has a rectangular cross section in consideration of the assembling property to the core part, the brazing property, and the like.

Next, the operation of this embodiment will be described. The high-temperature, high-pressure gas refrigerant compressed by the refrigerant compressor (not shown) is
It flows into the other header 6 from the inflow port 10 and flows to the one header 5 side through each flat tube 2 below the partition wall 9. Then, after making a U-turn at one of the headers 5, it flows into each of the other headers 6 again through each flat tube 2 between the partition wall 7 and the partition wall 9.

At this point in time, when passing through each flat tube 2, the refrigerant that has exchanged heat with the outside air due to the blowing of a cooling fan (not shown) is condensed and liquefied to a certain degree of dryness to form a gas-liquid two-phase state. Has become. The gas-liquid two-phase refrigerant flows through the receiver tube 4 and flows into the one header 5, but is hardly condensed in the receiver tube 4 having a large internal volume, and the dryness is almost the same as when flowing into the receiver tube 4. In this state, the receiver tube 4 flows out.

Thereafter, one header 5 makes a U-turn, passes through each flat tube 2 above the partition wall 8, flows into the other header 6, and then flows out from the outlet 11. Here, the refrigerant passing through each flat tube 2 is completely liquefied, further subcooled, and flows out of the refrigerant condenser 1 in a state having a degree of subcooling.

In the above operation, the receiver tube 4
When the flow rate of the refrigerant is small, the gas-liquid two-phase refrigerant flowing into the flow path completely separates vertically from the inlet of the receiver tube 4 by the action of gravity and flows in the receiver tube 4. At this time, since the gas-phase refrigerant flows faster than the liquid-phase refrigerant, the liquid refrigerant is likely to accumulate in the receiver tube 4.

Further, when the flow rate of the refrigerant is large, the gas and liquid are not immediately separated from the inlet of the receiver tube 4 but flow in a two-phase state in which the gas phase and the liquid phase are mixed for a while. Therefore, since the gas-phase refrigerant and the liquid-phase refrigerant flow at a constant speed,
The liquid refrigerant does not collect much in the receiver tube 4.

Due to the action of the receiver tube 4, the amount of refrigerant in the other cycle parts is large at high flow rates and small at low flow rates. In other words, when the load is high,
As shown in FIG. 3, the refrigerant flowing in the condensation zone (shown by A in FIG. 2) and the subcooling zone (shown by B in FIG. 2) upstream from the receiver tube 4 by the amount of the liquid refrigerant in the receiver tube 4. The amount increases and the degree of supercooling increases. On the other hand, when the load is low, the supercooling degree is decreased by the amount of the liquid refrigerant in the receiver tube 4. In FIG. 2, a high load state is shown by a solid line, and a low load state is shown by a broken line.

As described above, in the refrigerant condenser 1 of this embodiment, the amount of the refrigerant flowing in the supercooling region downstream of the receiver tube 4 changes in accordance with the fluctuation of the load, so that the cycle efficiency of the load is maximized. It becomes possible to realize a higher degree of supercooling.

Next, a second embodiment of the present invention will be described. FIG. 3 is an overall view of the refrigerant condenser 1 in which the receiver tube 4 is separate. In this embodiment, the receiver tube 4 is provided separately from the condenser body 1a. Therefore, in order to connect the condenser main body 1a and the receiver tube 4 with a pipe (not shown), both ends of the receiver tube 4, a position above the partition wall 7 of the header 5 and a partition wall 8 of the other header 6 are connected. Pipe connection ports 12, 13, 14, and 15 are provided between the partition wall 9 and the partition wall 9, respectively. In addition,
The flow of the refrigerant is shown by solid arrows in FIG. In the case of this embodiment, since the receiver tube 4 is a separate body,
It is not necessary to consider the assembling property and the brazing property as in the embodiment, and therefore, the shape is not restricted.

[0020]

According to the present invention, by installing a tube having a large internal volume in the middle of the refrigerant passage, it is possible to change the area of the refrigerant condenser which is spent for supercooling depending on the fluctuation of the load. it can. As a result, it is possible to realize the degree of supercooling that maximizes the cycle efficiency with respect to the load.

[Brief description of drawings]

FIG. 1 is an overall view of a refrigerant condenser.

FIG. 2 is a diagram showing changes in the amount of refrigerant in a refrigerant condenser.

FIG. 3 is an overall view of a refrigerant condenser showing a second embodiment of the present invention.

FIG. 4 is a diagram showing the cycle balance on the Mollier diagram when the amount of refrigerant enclosed changes.

FIG. 5 is a graph showing the relationship between supercooling degree and cycle efficiency.

FIG. 6 is a graph showing the relationship between the refrigerant flow rate and the optimum degree of subcooling.

[Explanation of symbols]

 1 Refrigerant condenser 2 Flat tube (refrigerant passage) 4 Receiver tube (tube)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Ohara 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihondenso Co., Ltd.

Claims (1)

[Claims] 1. A refrigerant condenser for condensing and liquefying a high-temperature, high-pressure gas-phase refrigerant flowing through a refrigerant passage by heat exchange with air, characterized in that a tube having a large internal volume is interposed in the middle of the refrigerant passage. Refrigerant condenser.