JPS5981453A - Refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration system in which the refrigerating capacity is improved by improving the condenser so that a suitably supercooled liquid refrigerant can be obtained at the inlet of the decompression device of the refrigeration system. For example, it is suitable for use in automobile air conditioning.

One conventionally known method for improving the refrigeration capacity of a refrigeration system is to provide a degree of supercooling to the refrigerant in the expansion valve, which is a pressure reducing device of the refrigeration system.
There is a method of increasing the enthalpy difference before and after evaporation of the refrigerant in the evaporator.

However, conventionally, in order to carry out this method, another condenser was provided downstream of the liquid receiver, and the liquid refrigerant coming out of the liquid receiver was cooled again to obtain supercooled refrigerant.

Therefore, according to this method, the number of condensers is increased and the condensers are therefore expensive, and the method also has the disadvantage that it is difficult to install the condensers in an automobile air conditioner or the like.

It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and to provide a refrigeration system in which supercooled refrigerant can be obtained at the inlet of the expansion valve by using only one condenser equivalent to the conventional one.

The origin of the present invention was the appearance of a condenser that divided the refrigerant passage +1P1 into two and connected the refrigerant in parallel in automobile air conditioners. To reduce the required power or improve cooling capacity.
In order to achieve this, the condenser has become larger and the pressure loss on the -C refrigerant side has also increased accordingly. In order to reduce this loss of pressure, the refrigerant passage can be divided into two and run in parallel)
It was granted. As will be described later, the present invention is directed to a refrigeration system equipped with such a condenser having two parallel refrigerant passage pipes. This means that having two parallel refrigerant passage pipes not only helps to obtain the supercooled refrigerant of the present invention, but also helps to reduce the above-mentioned pressure loss on the refrigerant side. This means that there are no drawbacks to the present invention.

The main point of the present invention is that two parallel refrigerant passage pipes are provided in the condenser of a cooling alt device, and the lengths of the respective passage pipes are set to be different from each other by an appropriate degree. The objective is to obtain a moderately supercooled drip refrigerant in the container at the receiving point. In a conventional combination of a condenser and a liquid receiver using one refrigerant passage pipe, refrigerant in both gas and liquid phases exists in the liquid receiver as saturated scum and saturated liquid. Therefore, the liquid refrigerant sent from the liquid receiver to the expansion valve is rarely in a supercooled state, and the degree of supercooling is usually 2.
℃~3℃ or less. On the other hand, if a liquid refrigerant with a degree of supercooling of several tens of degrees is injected into the liquid phase region in the liquid receiver in such a state, naturally there will be a gap between the gas and liquid phase refrigerant in the receiver. Heat exchange begins, but since heat exchange occurs only at the gas-liquid interface, it takes time to reach thermal equilibrium 1)i. Under normal usage conditions, the supercooled liquid refrigerant receives the liquid as it is. from the container to the expansion valve. As a method of obtaining the above-mentioned supercooled liquid medium, one additional layer is added in the condenser.
Add this refrigerant passage pipe, make its length longer than other passage pipes, and connect this long refrigerant passage pipe to the liquid phase section at the bottom of the receiver or to the outlet pipe of the receiver. This is the main point of the present invention.

The present invention will be described in detail below with reference to the drawings. In FIG. 1, the refrigerant vaporized in the evaporator 5 is transferred to the compressor 1.
The air is compressed into a high-temperature, high-pressure state, and is further sent to the condenser 2 through the pipe 6. The gas phase refrigerant sent is cooled and liquefied by the condenser 2, passes through pipes 9a and 9b, and is stored in the liquid receiver 3, and the liquid phase refrigerant in the liquid receiver 3 passes through the expansion block r4, which forms a pressure reducing device. Expanding, low-temperature, low-pressure gas-liquid 2
Condition! It becomes a refrigerant and is sent to the evaporator 5. Evaporator 5
The gas phase refrigerant that has been vaporized and has performed cooling action is sent to the compressor 1 again and this circulation process is repeated.

In the automobile air conditioner, cold air cooled by an evaporator 5 is blown into the vehicle interior to effect cooling, and the compressor 1 is driven by the automobile engine via an electromagnetic clutch 1a.

Next, the condenser 2, which forms the main part of the present invention, will be explained in detail.

In Fig. 2, the pipe 6 coming from the compressor 1 is connected to the branch 2c.
The small condenser section 2a is divided into a small condenser section 2a consisting of a refrigerant passage pipe with a shorter total length, and a large condenser section 2b consisting of a refrigerant passage tube with a longer total length. is piping 9
It is connected to the artificial pipe 3a at the upper part of the liquid receiver 3 by a. Further, the large condenser section 2b is connected to the lower liquid phase section of the liquid receiver 3. The refrigerant passage pipes of the two condenser sections 2a and 2b reciprocate in a meandering manner within the condenser, and in this embodiment, the straight section running in parallel is divided into five refrigerant passage pipes, and the small condenser section 2a has five pipes,
The large condenser section 2b has seven pieces.

The refrigerant passage pipe is made of aluminum material and has a flat cross-sectional shape. Further, a large number of corrugated fins 2d, also made of aluminum, are interposed between the refrigerant passage pipes running in parallel and are brazed to the refrigerant passage pipes. An output L1 pipe IO is connected to the liquid receiver 3, and only the liquid phase refrigerant in the liquid receiver 3 is sent to the 111 tension valve 4. In addition, 11 is a piping connection part.

The transition state of the gas-liquid phase of the refrigerant will be explained with reference to FIG. Part A indicated by a dot is the gas phase, and the part indicated by a broken line is the liquid phase.

First, looking at the small condenser section 2a, only the liquid phase refrigerant is sent from the liquid receiver 3 to the expansion valve 4, so it is impossible for vapor phase refrigerant to continuously flow into the liquid receiver 3. It is possible. Therefore, the refrigerant is almost completely condensed at the outlet of the small condenser section 2a. Regarding the large condenser section 2b, it is the same as the case of the small condenser section 2a that at least the refrigerant must have almost completely condensed in its output. However, the recondenser sections 2a, 2b
Considering the refrigerant flow rate that can pass through each of the large condenser section 21
), it can be seen that the position of completion of condensation is further limited. Naturally, the proportion of the refrigerant flow rate flowing through each condenser section 2a12b depends on the ratio of the magnitude of refrigerant pressure loss passing through each condenser section 2a and 2b, and the refrigerant pressure loss is mainly large in the gas phase region. As it condenses, it becomes smaller, and its value becomes almost negligible in the liquid phase region. Now, if we assume that the large condenser section 2b completes condensation at the same point as the small condenser section 2a, then the large condenser section 2b
In this case, the longer the pipe length, the longer the gas phase region, and the greater the refrigerant pressure loss.Therefore, the refrigerant flowing through the large condenser section 2b is smaller than the refrigerant flowing through the small condenser section 2a. On the other hand, the point at which condensation is completed is related to the flow rate of the gas phase refrigerant and the cross-sectional length of the heat transfer surface.

Therefore, the flow rate flowing through C1 large condenser section 2b is smaller than that of small condenser section 2.
If the flow rate is smaller than that flowing through a, the length of the gas phase region until condensation is completed becomes shorter, which contradicts the double assumption. It will be understood that the flow of the refrigerant is thus balanced with equal flow rates through the recondenser sections 2a and 2b and equal lengths of the gas phase regions in both condenser sections. . FIG. 3 shows this state. In the figure, heat is also radiated in the section <y-x> of the large condenser section 2b, so that supercooled refrigerant can be obtained. Moreover, since the liquid refrigerant supercooled in the large condenser section 2b is directly mixed into the liquid phase section at the lower part of the liquid receiver 3 through the pipe 9b, the supercooled liquid refrigerant is separated from the gas phase refrigerant. It can be supplied to the expansion valve 4 side without heat exchange.

The effects of the present invention have been confirmed through experiments, and the results are shown quantitatively in FIG. In the experiment, the total length δ1 (X+y) of the refrigerant passage pipes of the recondenser sections 2a and 2b was kept constant, that is, the heat dissipation area of the condenser section was kept constant, and only the ratio y/x was changed. It shows the ratio between the corresponding refrigerating capacity Q and the capacity Q1 when x=y. It can be seen from the figure that J-・) has a smell of about y/x-1,5 °ζ
The refrigeration capacity ratio Q/Q+ reaches its maximum, and when it exceeds about 1.7, it is lower than the standard value. This is because if y/x is too large, the total length of the refrigerant passage II & bamboo in the small condenser section 2a becomes short, and compared to the case where x=y, a sufficient heat transfer area cannot be obtained and the condensation pressure This seems to be due to the increase in In FIG. 4, SC indicates the degree of subcooling of the refrigerant flowing into the expansion valve inlet.

In addition, in the embodiment described above, the outlet of the large condenser section 2b is connected to the liquid phase section at the lower part of the liquid receiver 3 by the pipe 9b.
Of course, it is also possible to connect to the outlet pipe 10 of the liquid receiver 3 through the pipe 9b.

As described above, the present invention provides two parallel refrigerant passage pipes with different total lengths in the condenser, and the refrigerant passage pipes with a short total length (18 pipes as in the conventional case) are installed in the condenser. At the same time, the long refrigerant passage pipe is connected to the receiver 11 to the liquid phase section at the bottom of the container or to the outlet piping of the receiver, reducing refrigerant pressure loss to the condenser. There is no glue that can be done,
It is possible to have an appropriate degree of subcooling in the refrigerant supplied to a pressure reducing device such as an expansion valve, thereby improving the refrigerating capacity.

Moreover, according to the configuration of the present invention, only one condenser of the same size as the conventional one can be used, which is advantageous in that it is inexpensive and has advantages in terms of installation space and the like.

[Brief explanation of drawings]

Fig. 1 is a refrigeration system cycle diagram showing one embodiment of the present invention, Fig. 2 is a partial sectional view showing the condenser and liquid receiver portions of Fig. 1, and Fig. 3 is a gas-liquid refrigerant of Fig. 2. Fig. 4 is a characteristic diagram showing the rate of improvement in refrigerating capacity that changes depending on the ratio of the lengths of the two refrigerant passage pipes. In the figure, 1... Compressor, 2... Condenser, 3... Receiver 1 (l container, 4... Expansion valve, 5... Evaporator, 2a... Small condenser section, 2b...large condenser section, X...total length of the refrigerant passage pipe of the small condenser section, y...total length of the refrigerant passage pipe of the large condenser section. Fig. 1 Fig. 3 Go to figure 4

Claims (1)

[Claims] (1) A condenser that has two refrigerant passage pipes that are functionally parallel to each other, each of which reciprocates repeatedly, and a receiver provided downstream of the condenser. In a refrigeration system having a liquid container, if the two refrigerant passage 11fS pipes have different total lengths, the total length of the refrigerant passage pipe with the larger total length is the total length of the other refrigerant passage 11fS pipe. 1.7 times or less, and furthermore, the outlet of the refrigerant passage pipe with the smaller total length is set to fl.
iJ is connected to the inlet of the liquid receiver, and the refrigerant passage pipe having the larger total length is connected to the liquid phase section at the lower part of the liquid receiver or the outlet 1'' pipe of the liquid receiver. refrigeration equipment