JPS61140762A - Evaporator for non-eutectic mixed medium - 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 [Technical Field of the Invention] The present invention relates to an evaporator for a non-azeotropic mixed medium used in a refrigeration device, a heat pump, or a geothermal binary power generation plant using a non-azeotropic mixed medium. .

[Technical background of the invention and its problems]

Here, in order to understand where the evaporator for non-azeotropic mixed refrigerants is used, let's consider the case of a refrigeration system as an example. It is a diagram showing a schematic configuration of the device, in which 14 is a compressor, 17 is a condenser, 13 is an expansion mechanism, and 18 is an evaporator, and a non-azeotropic mixed medium is sealed in the device.

The medium compressed by the compressor 14 undergoes heat exchange with cooling water H such as industrial water in the condenser 17, and is condensed in a high pressure state. The liquefied medium is depressurized by the expansion mechanism 13 and guided to the evaporator 18 .

Here, the medium is heated in a countercurrent manner by a low-temperature heat source fluid stream supplied externally as cold water, evaporated at low pressure, and supplied to the compressor 14. The non-azeotropic mixed medium enclosed in C2 in the refrigeration equipment shown in Figure 10 is a mixture of two or more types of media with different boiling points, and the gas phase and liquid phase have different compositions, and under constant pressure. It is a medium that causes temperature changes during the phase change process even when evaporated or condensed. If such a medium is used and heat is exchanged between cold water and a non-azeotropic mixed medium in the evaporator in a counter-flow manner as described above, irreversible losses due to temperature differences in the heat exchange process will be reduced, and the equipment will be more expensive. Recently, refrigeration equipment using this type of non-azeotropic mixed media has attracted particular attention because of its ability to improve efficiency.

In implementing this, a great effect can be produced by matching the temperature drop of the low-temperature heat source fluid L (cold water) and the temperature rise in the evaporation process of the non-azeotropic mixed medium as much as possible.

Conventionally, as an evaporator for a non-azeotropic mixed medium, a two-phase heat exchanger is used in which evaporation occurs while flowing in a tube in order to exchange heat between a heat source fluid and a medium in a completely counter-flow manner. However, this two-phase flow type evaporator has a major drawback in that a pressure loss occurs in the flow direction of the medium ≦2. This pressure loss causes a decrease in the suction flow rate of the compressor and a decrease in the temperature change of the medium in the evaporator, so even if a non-azeotropic mixed medium is used, it has been difficult to fully utilize its characteristics.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to suppress irreversible energy loss during heat exchange between a non-azeotropic mixed medium and a heat source fluid, and to reduce the pressure of the medium. An object of the present invention is to provide a high-performance evaporator for non-azeotropic mixed media that causes almost no loss.

[Summary of the invention]

In order to achieve the above object, the present invention provides an evaporator for a non-azeotropic mixed medium that heats and evaporates a non-azeotropic mixed medium with a heat source fluid, in which the evaporator is connected to a plurality of evaporation chambers along the flow direction of the heat source fluid. a steam extraction port is provided in each evaporation chamber, and after the non-azeotropic mixed medium supplied from the outside to the evaporation chamber located on the most downstream side of the heat source fluid is partially evaporated in each evaporation chamber, A refrigerant liquid conduction path is provided between adjacent evaporation chambers so that the adjacent heat source fluid enters the evaporation chamber C Miura on the upstream side.

〔Effect of the invention〕

According to the present invention, since non-azeotropic mixed media having different compositions can be applied to a plurality of evaporation chambers individually at the same pressure level, the temperature of the medium in the evaporator can be changed to the pattern C of the temperature change of the heat source fluid.
: Can be changed into a step-like shape, reducing irreversible loss during heat exchange.

Moreover, unlike a two-phase flow evaporator, no pressure loss occurs, so the characteristics of the non-azeotropic mixed medium can be effectively and appropriately utilized.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIGS. 1 and 2 are diagrams showing a schematic configuration of an evaporator for a non-azeotropic mixed medium, which is an embodiment of the present invention.

As shown in Fig. 1, one of the major features of the evaporator for non-azeotropic mixed media according to the present invention is that its interior has a plurality of (four in Fig. 1) evaporation chambers along the flow direction of the heat source fluid. (The first evaporation chamber 1a, the second evaporation chamber 1b, the eighth evaporation chamber 1c, and the fourth evaporation chamber 1d). That is, the right side opening and left side opening of the cylindrical body 2, which is arranged with its axis in the horizontal direction, are respectively closed by the lids 8a and 8b, and furthermore, the spaces formed between the attached bodies 8a and ab are The first evaporation chamber 1 is divided by partition plates 4 (eight in the figure).
A to fourth evaporation chambers 1d are provided. Above each evaporation chamber is a steam outlet (first steam outlet 5a, second steam outlet 5b, eighth steam outlet 5C1, fourth steam outlet 5d).
is attached to the evaporator, and as shown in FIG.
, 3b s and are arranged so as to penetrate through the partition plate 4. A heat source fluid intake chamber 8a is provided at one end of the heat transfer tube bundle, that is, on the right side of the lid 8a, and a heat source fluid intake chamber is provided at the other end of the heat transfer tube bundle 7, that is, on the left side of the lid 3b. A chamber 8b is provided, and the intake chamber 8a and the extraction chamber 8b communicate with each other via the heat exchanger tube bundle 7. The heat source fluid stream is supplied to the intake chamber 8a, flows inside the heat transfer tube 6, and then guided to the outside from the extraction chamber 8b.

Furthermore, the evaporation chamber (first
In the figure, there is a medium population 9 in the first evaporation chamber 1a), and a medium liquid conduit path (first conduit path 10aS) between adjacent evaporation chambers.
Since the second conduction path 10b1 and the eighth conduction path 10c) are provided, the non-azeotropic mixed medium 11 is supplied from the outside into the first evaporation chamber la through the refrigerant population 9, and the heat transfer tube bundle 7 is submerged in C. When the heat source fluid is passed through each heat transfer tube 6 of the heat transfer tube bundle 7, the medium supplied from the outside is partially evaporated by pool boiling in each evaporation chamber, and then sequentially flows into the adjacent heat source fluid upstream side. into the evaporation chamber.

That is, the non-azeotropic mixed medium 11 supplied from the outside to the first evaporation chamber 1a is heated by the heat source fluid LC in the first evaporation chamber 1a, and a part of it becomes steam 11a and flows through the steam outlet 5a.
is taken out of the evaporator. On the other hand, the unevaporated liquid 118' flows into the second evaporation chamber 1b through the first conduit 10a, and from then on, similar operations are performed one after another to produce steam 11b, llc from each evaporation chamber, respectively.

The lid is taken out to the outside.

In the figure, llb' and llc' are respectively second conductive paths iob.
and shows the unevaporated liquid of the medium passing through the eighth conduction path 10c. Here, in the evaporator of this embodiment, a pump is not used and the medium is made to flow into adjacent evaporation chambers sequentially by the difference in liquid hydrostatic head, so as shown in FIG. A difference in liquid level occurs. If this liquid level difference becomes too large, you can install a small pump in the medium liquid conduit passage to send the medium liquid to the adjacent evaporation chamber, or install the evaporator with a slight inclination to increase the medium liquid level. It can also be made easier to flow.

Now, the function of the evaporator for non-azeotropic mixed media according to the present invention, which has been described in detail above, will be explained by taking as an example the case where C2 is used in a refrigeration system as shown in FIG.

The refrigeration system shown in FIG. 8 differs from the refrigeration system shown in FIG. 10 used to explain the prior art in that it uses the evaporator 12 for non-azeotropic mixed media according to the present invention. Identical parts are designated by the same reference numerals and their explanations will be omitted. In FIG. 8, the non-azeotropic mixed medium 11, which has been reduced in pressure by the expansion mechanism 13 and has become a two-phase state, enters the medium inlet 9 installed in the evaporation chamber on the most downstream side of the heat source fluid stream, as explained in FIG. After being partially evaporated in each evaporation chamber, it sequentially flows into the adjacent evaporation chamber via the conduit. The steam generated in each evaporation chamber is taken out from the first steam outlet 5a to the fourth steam outlet 5d, and after joining together, is led to the suction port of the compressor 14.

With this structure, non-azeotropic mixed media with different compositions can be applied to multiple evaporation chambers individually at the same pressure level, so the temperature of the medium can be adjusted in the evaporator to follow the pattern of temperature change of the heat source fluid. It is possible to change the step shape C2 to reduce irreversible loss during heat exchange.

The effect will be specifically explained using a non-azeotropic mixed medium consisting of two components (A and B) as an example. FIG. 4 is a diagram showing the vapor-liquid equilibrium relationship at a constant pressure P=Po (evaporator internal pressure) of the mixed medium.

t on the vertical axis means temperature, and XA on the horizontal axis means the weight fraction of human components. tXA at xA=0 (B component only) =
1A in 1 (human component only) is the B component and A, respectively.
component pressure P. In the figure, B has a higher saturation temperature, that is, it is more likely to evaporate. In the figure) (A-Q; t=tB, xA=1; t=
Two curves passing through two points tA are drawn. The upper curve is called the gas phase line, and the lower curve is called the liquidus line. In the equilibrium state, only vapor can exist in the mixed medium in the region above the gas phase line, and only liquid can exist in the region below the liquidus line. The region between the two lines is a region where liquid and gas coexist.

Now, the state inside the evaporator according to the present invention explained in FIGS. 1 to 3 is shown in FIG. 4 as follows. Since the medium 11 at the evaporator inlet is in a two-phase state, it is represented by point 1 located between the gas phase line and the liquidus line, but when it is heated by the heat source fluid L2 in the first evaporation chamber, Due to the added effect of liquid recirculation, the liquid and vapor in the first evaporation chamber are respectively at point a'
The component state is as shown by point a. As a matter of course,
The component of the unevaporated liquid 118' flowing into the second evaporation chamber through the first conduit 10a is also indicated by point a'. The temperature at that time is 1a.

Similarly, the liquid and vapor in the second evaporation chamber are connected to point b' at #8.
# I Point C' and point C 4th ff #
# Represented by points d' and d, whose temperature is ta+'b
+t. +td becomes higher in the order of C2.

FIG. 5 shows the temperature inside the evaporator and the temperature of the heat source fluid. As can be seen from the figure, the fourth evaporation chamber 1
The heat source fluid flowing from the d side to the first evaporation chamber la side is a line segment t
As shown by L, the temperature decreases in the flow direction, but as mentioned earlier, the medium temperature in the evaporator increases from the first evaporation chamber to the fourth evaporation chamber as t, < tb < t,
<t4, which increases stepwise, so that irreversible energy loss (corresponding to the shaded area in Figure 5) in C2 during heat exchange between the two is significantly suppressed compared to when a single component medium is used. be able to. In addition, unlike a two-phase flow type evaporator, there is no pressure loss, so the characteristics of a non-azeotropic mixed medium can be effectively utilized.

Note that the evaporation chamber of the evaporator for non-azeotropic mixed media of the present invention is not limited to one partitioned by partition plates, and a plurality of evaporators may be provided as independent evaporators.

FIG. 6 shows a modification of the embodiment of the present invention explained in FIGS. 1 and 2. FIG. The difference between the evaporator shown in FIG. 6 and the evaporator shown in FIGS. 1 and 2 is that the evaporator shown in FIG.

10c) is provided in the evaporator by removing a portion of the lower part of the partition plate 4. The effects of the invention are exactly the same as those of the previous embodiments.

The evaporator for non-azeotropic mixed media according to the present invention is not necessarily limited to the horizontal type as in the above-mentioned embodiments, but is
It can also be used as a vertical type as shown in the figure. In this case, C: is the evaporation chamber (first
Evaporation chamber 1a) is the other second evaporation chamber 1b to fourth evaporation chamber 1
The evaporator is installed above d, and after the medium is partially evaporated by pool boiling in each evaporation chamber, it sequentially flows into the adjacent evaporation chamber located below in the form of overflow. . Components that are the same as those in the previous embodiment are designated by the same reference numerals, and their description will be omitted.

Furthermore, the evaporator for non-azeotropic mixed media according to the present invention C2 is not necessarily limited to the pool boiling evaporation type described above. FIG. 8 shows another embodiment according to the present invention.

This evaporator is of a falling film evaporation type in which the medium is evaporated while flowing down outside the heat transfer tube 6, unlike the previous embodiment.

Nice repeaters for medium liquid dispersion for each evaporation chamber (first distributor 15a, second distributor i5b, sa distributor 15c).

fourth distributor 15d) and medium liquid dispersion pumps (first pump 16a, second pump 16b, third pump 1
6c and a fourth pump 16d) are installed, and the liquid medium is caused to flow down outside the heat transfer tube, there is no major structural difference from the previous embodiment, and the same parts are designated by the same reference numerals and the explanation thereof will be omitted. The effects obtained in this example are similar to those of the previous example, and thereby a high-performance evaporator for non-azeotropic mixed media can be provided.

Now, in the embodiments described above, the structure is such that the medium is completely evaporated in the evaporation chamber (fourth evaporation chamber 1d) located on the most upstream side of the heat source fluid, but the present invention can also be used in other cases. Works effectively.

FIG. 9 is a diagram showing another embodiment according to the present invention. 9th
The difference between the embodiment in the figure and the embodiments described so far is that the medium liquid 11d' in the evaporation chamber (fourth evaporation chamber 1d) on the most upstream side of the heat source fluid is Evaporation chamber 1
The reason is that a connecting pipe 19 for medium liquid dispersion is provided for returning a portion of the liquid to a). In this case, in C2, the medium liquid 11d' is transferred by the pump 20. The other parts are completely the same as those in the embodiment shown in FIG. 1, and the same parts are given the same reference numerals and the explanation thereof will be omitted. With this structure, the medium liquid can be recirculated within the evaporator, so even if the component composition of the non-azeotropic mixed medium 11 supplied from the outside to the evaporator is the same, by changing the amount of recirculation. The width of the temperature change of the medium within the evaporator can be arbitrarily changed, making it possible to use the evaporator under optimal conditions.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along arrow X-X in FIG. 1, and FIG. 8 is a non-azeotropic A cycle configuration diagram of a refrigeration system incorporating a mixed medium evaporator, FIGS. 4 and 5 are explanatory diagrams of the operation of the embodiment, and FIG. 6 is a diagram showing a modification of the embodiment shown in FIG. 1. FIG. 7 to FIG. 9 are diagrams showing other embodiments of the present invention, and FIG. 10 is a cycle configuration diagram of a refrigeration system for explaining the prior art related to an evaporator for a non-azeotropic mixed medium. L...Heat source fluid 1a...First evaporation chamber 1b...Second evaporation chamber 1c...
・Eighth evaporation chamber 1d...Fourth evaporation chamber 5a...First vapor outlet 5b...Second vapor outlet 5c...Third vapor outlet 5d...Fourth vapor outlet 10a ...First
Conduit path iob...Second conduit path 10c...Eighth conduit path 11...Non-azeotropic mixed medium 19...Connection piping for medium liquid recirculation Agent Patent attorney: Kensuke Chika (and one other person) ) Figure 8 1-1. 7 t3 /4th, 4th figure θ l'A precept to 廿礒χA 5th figure 7th figure 8th figure 9th figure / q--be 迩迩人 re-wandering ring θ --- piece J7゜Figure 10

Claims (2)

[Claims] (1) In an evaporator for a non-azeotropic mixed medium that heats and evaporates a non-azeotropic mixed medium with a heat source fluid via a metallic heat transfer surface, the evaporator is arranged in a plurality of evaporators along the flow direction of the heat source fluid. Each evaporation chamber is provided with a steam outlet, and a non-azeotropic mixed medium supplied from the outside to the evaporation chamber located on the most downstream side of the heat source fluid is partially evaporated in each evaporation chamber. 1. An evaporator for a non-azeotropic mixed medium, characterized in that a medium liquid conduction path is provided between adjacent evaporation chambers so that the medium liquid sequentially flows into the evaporation chambers on the upstream side of the adjacent heat source fluid. (2) A medium liquid recirculation connection pipe is provided for returning the refrigerant liquid in the evaporation chamber located on the most upstream side of the heat source fluid to the evaporation chamber on the most downstream side of the heat source fluid. The evaporator for non-azeotropic mixed media according to item 1.