JPH0711367B2 - Absorption refrigeration cycle - Google Patents

Description

The present invention relates to an air-cooled absorption refrigeration cycle.

[Conventional technology]

First, an absorption refrigeration cycle using water as a refrigerant and lithium bromide (LiBr) as an absorbent will be described with reference to FIG. 1 (Japanese Patent Publication No. 46-32384).

Water, which is a refrigerant, enters the shell of the evaporator 1 kept at a low pressure, takes heat from the cold water flowing in the cold water pipe 2, evaporates, and reaches the purpose of freezing. The evaporated refrigerant gas flows toward the absorber 3. In the shell of the absorber 3, there is an aqueous solution of lithium bromide kept at a constant temperature by the cooling water flowing in the pipe 4, and the evaporated refrigerant gas is absorbed in this solution,
A low temperature heat exchanger 6 by means of a solution circulating pump 5 to form a dilute solution.
Sent to. The diluted solution exiting here is divided into two parts, one of which is directly sent to the low temperature regenerator 7, and the other is further sent to the high temperature regenerator 9 through the high temperature heat exchanger 8. High temperature regenerator 9
There is a boiler 10 therein, and the heating by the boiler 10 evaporates the refrigerant vapor from the dilute solution to separate it into a concentrated solution and a refrigerant vapor. The refrigerant vapor heats the dilute solution supplied into the pipe of the low temperature regenerator 7 and sent into the shell to separate into a concentrated solution and a refrigerant vapor. In this way, the high temperature regenerator 9
And the refrigerant gas separated from the solution in the low temperature regenerator 7 reaches the condenser 11, is cooled by the cooling water passing through the cooling water pipe 4 and returns to the liquid refrigerant, and is provided in the evaporator 1 via the pipe 12.
One cycle of the refrigerant cycle. Further, the concentrated solution after the refrigerant is evaporated in the high temperature regenerator 9 passes through the high temperature heat exchanger 8 and merges with the concentrated solution coming from the low temperature regenerator 7, and then returns to the absorber 3 via the low temperature heat exchanger 6 again. The refrigerant vapor from the evaporator 1 is absorbed to form a dilute solution, which completes the solution cycle. Reference numeral 13 is a refrigerant pump for circulating the refrigerant in the evaporator 1.

As shown in FIG. 1, the temperature of the evaporator 1 is about 4 ° C, the temperature of the absorbing liquid leaving the absorber 3 is 40 ° C, and the temperature of the high temperature regenerator 9 is about 4 ° C.
It is 150 ℃.

[Problems to be Solved by the Invention]

Of these, a particularly important temperature is the operating temperature of the absorber 3, and it is necessary that the temperature is not so high in order not to generate crystals in the lithium bromide aqueous solution. In addition, in the double-effect absorption cycle, if the temperature of the high temperature regenerator is high, the service life cannot be sufficiently extended in consideration of corrosion, and also in order to operate without exceeding atmospheric pressure, the absorber 3 and the condenser are condensed. It is not preferable to raise the temperature of the vessel 11.

From these viewpoints, the temperature of the absorption liquid at the outlet of the absorber and the operating temperature of the condenser should be about 40 ° C in the usual configuration.

On the other hand, in most of the water-lithium bromide absorption type refrigerators, the absorber and the condenser are conventionally cooled by cooling water. Especially in the double-effect absorption refrigeration cycle, it was impossible to cool the absorber and the condenser with air. This is because the operating temperature of the absorber or condenser obtained by heat exchange by air cooling is about 50 ° C according to the condition of cooling air in the midsummer, and it is possible to realize the operating temperature of about 40 ° C already mentioned above. Because it was impossible.

That is, the outside air temperature obtained in the midsummer is about 32 to 35 ° C, and therefore the temperature of the air after cooling the absorber (or condenser) is 40 to 45 ° C. This is because if the temperature difference required for heat transfer is added to this, the operating temperature of the absorber (condenser) becomes approximately 50 ° C, and the operating temperature of approximately 40 ° C that was previously possible cannot be realized.

The parts of the absorption refrigeration cycle that require cooling operate at different temperatures, such as the temperature of the condenser, the temperature of the absorption liquid flowing into the absorber from the heat exchanger, and the temperature of the absorption liquid flowing out of the absorber, at 10 to 20 ° C. is doing.

The cooling air also has a temperature difference of about 10 ° C. from the outside air temperature to the temperature released after cooling the absorber or the condenser.

An object of the present invention is to effectively utilize the above-mentioned different temperature levels, and to cool a necessary portion of a low temperature with air of a low temperature to obtain the same degree as that of an absorption refrigeration cycle cooled with cooling water. An object of the present invention is to provide an absorption refrigeration cycle that realizes low absorber and condenser operating temperatures.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser, an absorption type refrigeration cycle in which a plurality of air-cooled absorbers and a solution pump are operatively connected by piping. , The refrigerant vapor generated in the evaporator is introduced in parallel to the absorber by arranging the absorber so that the introduction parts of the refrigerant vapor in the upper part of the plurality of absorbers communicate with each other, and the high temperature regenerator and the low temperature The absorber is connected via the solution pump so that the absorbent from the regenerator flows in series to the plurality of absorbers, and the outlet temperature of air and the absorbent are close to the inlet temperature of the cooling air of the absorber. This is to perform heat exchange with a nearby absorbing liquid via the wall surface of the flow path through which the absorbing liquid flows so that the temperature of the absorbing liquid at the outlet of the absorber becomes lower than the temperature of the cooling air discharged from the absorber.

Further, in order to achieve the above object, the present invention provides a high temperature regenerator,
In an absorption refrigeration cycle in which a low-temperature regenerator, an evaporator, a condenser, a plurality of air-cooled absorbers and a solution pump are operatively connected to each other, the refrigerant vapor introduction portions above the plurality of absorbers are mutually connected. The refrigerant vapor generated in the evaporator is introduced in parallel to the absorber by disposing the absorber so as to communicate with the absorber, and the absorbing liquid from the high temperature regenerator and the low temperature regenerator is connected in series to the plurality of absorbers. The absorber is connected via the solution pump so as to flow, and the air near the outlet temperature of the cooling air of the absorber and the absorber near the inlet temperature of the absorber are passed through the wall surface of the flow path through which the absorber flows. The heat is exchanged so that the temperature of the absorbing liquid at the outlet of the absorber is lower than the temperature of the cooling air discharged from the absorber.

Further, the present invention is an absorption refrigeration cycle using a condenser and an air-cooled absorber. In the absorption-type refrigeration cycle, air close to the inlet temperature of the absorber cooling air or air close to the outlet temperature and absorption close to the outlet temperature of the absorber absorption liquid are absorbed. The liquid or the absorbing liquid close to the inlet temperature is heat-exchanged through the heat transfer wall.

Further, the present invention provides a means for guiding the air cooled in the absorber to the upstream absorber of the absorbing liquid in an absorption refrigeration cycle using a condenser and an absorber cooled by air.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 shows an embodiment thereof, in which the absorber 3 of FIG. 1 is air-cooled, and the absorber 3 is arranged in a vertical direction (or an oblique direction). Low temperature regenerator 7, high temperature regenerator 9
The high-temperature and high-concentration absorbent 23 that has passed through the heat exchangers 8 and 6 is sprayed above the cooled side of the absorber 27 and is cooled by passing through the wall surface 22 while absorbing the refrigerant vapor 24. Flow to. On the other hand, the surface on the opposite side through the heat transfer wall is fin 25
The cooling air is a cooling surface provided with air, and the cooling air 19 flows from the lower side to the upper side.

By doing so, the temperature of the solution at the outlet 28 of the absorber 27 becomes the inlet temperature of the cooling air, that is, the outside air temperature plus a required transfer temperature difference (several degrees Celsius to 10 degrees Celsius). Can be about 40 ° C.

FIG. 3 is a modification of FIG. 2 and shows the wall surface 26 of the air cooler and the cooling wall surface 22 of the absorber when the portion for absorbing the refrigerant vapor of the absorber and the air cooling heat exchanger cannot be installed close to each other. It is connected with a heat pipe 29.

As in FIG. 3, FIG. 4 is provided with a pump 32 for driving the heat medium 31 forcibly in each section when necessary,
In addition, the intermediate heat medium 31 circulates through the small sections on the side that cools the absorber and the side that is cooled by air, and this is an example using a kind of deformed heat pipe. In each of the examples of FIGS. 3 and 4, only the intermediate heat medium is present, and the behaviors of the absorbing liquid and the cooling air almost have the same relationship as in the case of FIG. In addition, the absorption liquid cooled in the absorber is a sensible heat-cooling portion of the solution flowing out of the heat exchangers 8 and 6 shown in FIG. There is a portion that mainly cools the absorption heat of the refrigerant vapor while absorbing it.
The former has a very high temperature, and if this part is cooled separately, the part acting as an original absorber that absorbs the refrigerant vapor as an absorber can be operated at a lower temperature.

FIG. 5 shows an embodiment thereof, in which the cooling air 19 absorbs vapor and cools the absorbed heat in the absorber 34,
Heat is exchanged in the order of a section 33 for cooling the condenser and a section 35 for cooling the sensible heat of the relatively high-temperature absorbing liquid flowing into the absorber. In this way, sections 34 and 33 are
Only the temperature difference of the temperature rise of the air generated due to the heat exchange with the section 35 cooling the sensible heat can be cooled by the air of the low temperature. The operating temperature of the absorption refrigeration cycle is determined by the sections 33 and 34 and is not affected by the section 35 of sensible cooling, so that the temperature of the cooling air can be effectively used.

When heat exchange is performed between air and absorbing liquid via a heat medium, using absorbing liquid as the heat medium simplifies the configuration and reduces the temperature required for heat exchange between the heat medium and absorbing liquid. it can.

FIG. 6 shows an embodiment thereof, in which the absorption liquid cooled by the air heat exchangers 35 to 38 is jetted into the sections 44 to 47 of the absorber 3 to absorb the refrigerant vapor 24. Similar to the previous embodiment, the air coolers 35 to 38 are divided into a large number. Although the absorption liquid flowing from the heat exchanger 6 to the absorber 3 in the cycle of FIG. 1 has a high temperature, it is first cooled in the section 35 of the air heat exchanger of FIG. Classification of air heat exchange
35 is the segment cooled at the highest air temperature. The absorbent is then jetted into section 44 of the absorber. Since this portion is filled with the refrigerant vapor 24 sent from the evaporator 1, the absorbing liquid absorbs the refrigerant vapor, and the temperature rises due to the absorbed heat. This absorption liquid is sent by a pump 41 to the next section 36 of the air heat exchanger for cooling.

Since this section 36 is cooled with air at a temperature lower than that of section 35, the absorbing liquid is cooled to a temperature lower than that of section 44 of the absorber and jetted to the next section 45. Thus, the absorber sections 44, 45, 46, 47 are successively supplied with the absorbing liquid cooled to a low temperature. On the other hand, it absorbs the refrigerant vapor and the concentration of the absorbing liquid is 44
~ 47 and gradually decreases (thus the absorption capacity decreases at the same temperature), but the temperature also decreases accordingly, so that the same level of absorption continues. With such a configuration, the temperature of the solution at the outlet of the absorber can be heat-exchanged with the air temperature at the air inlet of the air heat exchanger, and the heat transfer to the inlet temperature of air, which is the basic relation of the present invention, can be performed. It is possible to realize the relationship that the temperature obtained by adding the necessary temperature difference to the temperature of the solution at the outlet of the absorber.

In the above embodiment, the heat of absorption generated in each section of the absorber 3 causes a considerable increase in the temperature of the absorption liquid. For example, if the entire section is divided into one as shown in FIG. 7 and evaluated by the flow rate of the solution used in the cycle as shown in FIG. 1, the temperature at the absorber outlet 50 is The temperature of the absorbing liquid 51 flowing into the chamber rises by about 10 ° C to 20 ° C due to the heat of absorption.

If the temperature of the absorbing liquid at the absorber outlet 50 is the temperature of the air 19 at the inlet of the air heat exchanger 35 plus the temperature required for heat transfer, and if 10 to 20 ° C. is further added, the absorption of about 40 ° C. The absorption liquid temperature at the outlet of the vessel cannot be realized.

As a solution to this problem, it is easy to increase the flow rate by the pump 41 to an extremely large amount as compared with the amount normally used, but the temperature of the absorbing liquid at the absorber outlet 50 should be 40 ° C.
The temperature of the absorbing liquid at the absorbing liquid inlet 51 is 40 ° C.
Therefore, the absorption liquid at the absorber inlet 51 cannot be cooled by the air temperature at the outlet of the air heat exchanger 35. Of course, the impractical power of the pump 41 is also a big obstacle. By increasing the number of divisions in Fig. 6, the temperature rise of the absorbent in each division 44-47 decreases in inverse proportion to the number of divisions compared to 50, 51 in Fig. 7, and the pump The power of can also be configured at the level conventionally used. This is a great effect of the configuration of FIG. 6, but in order to further reduce the temperature rise of the absorbing liquid due to the heat of absorption in each of the sections 44 to 47, the reference numeral in FIG.
As shown in 49, it is effective to provide a system to recirculate each section.

However, even in the structure shown in FIG. 7, the amount of the absorbing liquid sent by the pump 41 is larger than that of the absorbing liquid 23 flowing into the absorber 3, and there are many cases of recirculation. In order to distinguish this from the range in which recirculation is effective, the recirculation amount of the absorption liquid should be 20 times or more the amount of the refrigerant to be absorbed in order for the temperature rise of the absorption liquid in each section to be sufficiently small. However, in order to reduce the power of the pumps 41 to 43, it is desirable that the amount of the absorbing liquid 23 flowing into the absorber 3 is 10 times or less.

In the embodiment shown in FIG. 6, the absorbing liquid is jetted into the space to directly absorb the refrigerant. However, as shown in the embodiments of FIGS. 3 and 4, the heat pipe (or the intermediate heat medium Also in the heat exchange used, it is also sufficiently effective to use an absorbing liquid (or a refrigerant) as the intermediate heat medium and reduce the types of fluids constituting the entire system. Since this structure can be fully understood from FIGS. 3 and 4, detailed description based on the drawings is omitted.

In FIG. 6, the system path recirculation system path 49 using a large number of sections using a large number of pumps has explained the case where the absorbing liquid is directly ejected to the space for absorbing the refrigerant to cause the absorbing action. The same effect can be obtained even when the absorbing section and the intermediate heat medium exchange heat through the heat transfer wall.

FIG. 8 shows an embodiment thereof, and each section of the absorber 3
The intermediate heat medium 53 passes through 44 to 47 sequentially through the heat transfer tube groups 55 to 58 of the absorber. The behavior of the absorbent in pumps 41-43 and absorber sections 44-47 is the same as in FIG. The intermediate heat medium 53 is adapted to sequentially exchange heat with the air heat exchangers 35 to 38.

In addition to the many embodiments described above, many other configurations are conceivable for implementing the essential contents of the present invention. For example, in the embodiment of FIG. 2, the outlet of the absorber 27 does not have to be exactly cooled by the inlet of air, and the absorber temperature is low enough to realize the absorption refrigerant cycle (for example,
It should be about 40 ℃). For example, the embodiment shown in FIG. 2 can be modified as shown in FIG. Air 19 is introduced into the portion 61 corresponding to the middle of the flow of the absorbing liquid and is made to flow in the directions of arrows 62 and 63.

The parts indicated by the numbers in FIG. 9 are the same as the parts with the same numbers in FIG.

Even with this structure, it is apparent that the temperature of the absorbing liquid that exits the absorber can be lowered if the portion indicated by the arrow 62 is close to the outlet of the absorber 27.

For example, the flow of air and absorbing liquid is shown in Fig. 2, Fig. 3, Fig. 4,
Even if the embodiment shown in FIGS. 5, 6 and 8 is modified so that the outflow portion of the absorbing liquid and the air inlet portion do not necessarily correspond to each other, the temperature of the absorbing liquid flowing out of the absorber will be the cooling air. Of the heat transfer temperature difference (eg 5 ° C) to the inlet temperature (eg 33 ° C) of 1.5
If it is about doubled (in this example, the absorption liquid temperature is 40.5 ° C)
Therefore, a sufficient absorption refrigeration cycle can be constructed. Obviously, these modifications are also effective examples of the present invention.

If the outside air temperature becomes low, the absorption temperature shifts to the low temperature side without changing the evaporation temperature. That is, the concentration of the absorbing solution becomes thin and shifts to the low temperature side. Therefore, even if the outside air temperature is lowered from 20 ° C. to 30 ° C., air cooling can be realized without any problem.

〔The invention's effect〕

As described above, according to the present invention, it is possible to realize the low operating temperatures of the absorber and the condenser, which are as low as those of the absorption refrigeration cycle cooled by cooling water, by air cooling.

[Brief description of drawings]

FIG. 1 is a system diagram of a general absorption refrigeration cycle, FIG. 2 is a system diagram showing a main part of an embodiment of the present invention, FIG. 3, and FIG.
FIG. 5, FIG. 6, FIG. 6, FIG. 7, FIG. 8 and FIG. 9 are system diagrams showing the essential parts of another embodiment of the present invention. 1 ... Evaporator, 2 ... Cold water pipe, 3 ... Absorber, 4 ...
Tube, 5 ... Solution circulation pump, 6 ... Low temperature heat exchanger, 7 ...
… Low temperature regenerator, 8 …… High temperature heat exchanger, 9 …… High temperature regenerator, 10 …… Boiler, 11 …… Condenser, 12 …… Tube, 23 …… Absorbing liquid, 22 …… Inner wall surface, 24… … Refrigerant vapor, 25 …… Fine,
19 …… Cooling air, 27 …… Air absorber, 28 …… Absorber outlet solution, 26 …… Outer wall surface, 29 …… Heat pipe, 32 …… Drive pump, 31 …… Heat medium, 30 …… Heat Medium piping, 34 ... Absorption cooler, 33 ... Condensing cooler, 35,36,37,38 ... Solution cooler, 44,45,46,47 ... Absorber, 49 ... Recirculation path, 50,
51 ... Absorbing liquid, 52 ... Cooling air (outlet), 53 ... Intermediate heat medium, 55, 56, 57, 58 ... Heat transfer tubes.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-56-124862 (JP, A) JP-A-57-12272 (JP, A) JP-A-54-124360 (JP, A)

Claims (3)

[Claims] 1. An absorption type refrigeration cycle in which a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser, a plurality of air-cooled absorbers and a solution pump are operatively connected by piping, and the plurality of absorbers are used. While introducing the refrigerant vapor generated in the evaporator in parallel to the absorber by disposing the absorber so that the upper refrigerant vapor introduction parts communicate with each other, the absorption liquid from the high temperature regenerator and the low temperature regenerator Is connected to the absorber via the solution pump so as to flow in series to the plurality of absorbers, and absorbs the air close to the inlet temperature of the cooling air of the absorber and the absorber close to the outlet temperature of the absorber. An absorption type refrigeration cycle characterized in that heat is exchanged through a wall surface of a flow path through which the liquid flows so that the temperature of the absorbing liquid at the outlet of the absorber is lower than the temperature of the cooling air discharged from the absorber. 2. The absorption type refrigeration cycle according to claim 1, wherein the absorbers are arranged obliquely. 3. An absorption refrigeration cycle comprising a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser, a plurality of air-cooled absorbers and a solution pump operatively connected to each other in the absorption refrigeration cycle. While introducing the refrigerant vapor generated in the evaporator in parallel to the absorber by disposing the absorber so that the upper refrigerant vapor introduction parts communicate with each other, the absorption liquid from the high temperature regenerator and the low temperature regenerator Is connected to the absorber via the solution pump so as to flow in series to the plurality of absorbers, and absorbs air close to the outlet temperature of the cooling air of the absorber and absorbing liquid close to the inlet temperature of the absorbing liquid. An absorption type refrigeration cycle characterized in that heat is exchanged through a wall surface of a flow path through which the liquid flows so that the temperature of the absorbing liquid at the outlet of the absorber is lower than the temperature of the cooling air discharged from the absorber.