JPH0417336B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorption refrigerating machine (hereinafter referred to as an absorption chiller) that utilizes an absorption refrigeration cycle and is used for cooling cold water, making ice, or for heat pumps.

The absorption chiller that has been commonly used for a long time is
As shown in FIG. 1, an eliminator 1 is provided between an evaporator 2 and an absorber 3, and the refrigerant vaporized in the evaporator 2 is absorbed by the absorption liquid flowing down the surface of the heat exchanger 4 of the absorber. It has a vessel body 5 of. and,
The heat exchanger 4 built into the absorber 3 was formed as a single heat exchanger with no temperature difference, and the relationship between the temperature gradient inside the absorber, the absorption liquid concentration, etc. was not particularly considered. .

The structure of conventional absorption chillers like this is not a problem when used in combination with a refrigerant absorbent where the vapor pressure of the absorbent is extremely low, such as an absorption chiller using a water-lithium halide absorption refrigeration cycle. , an absorption chiller using an organic absorbent with a relatively high vapor pressure, for example, the combination of refrigerant and absorbent is Freon 22-tetraethylene glycol dimethyl ether, TFE (trifluoroethanol)-N methyl 2-pyrrolidone. In an absorption chiller using a refrigerant, etc., it is not only difficult to prevent the absorbent gas from getting mixed into the flow of the refrigerant gas, but also when the absorption of the refrigerant into the absorption liquid progresses, depending on the temperature conditions, the absorbent may vaporize. A change to the vapor phase occurred, and the absorption capacity of the refrigerant was significantly reduced.

The present invention was developed in view of these points, and in order to bring the vapor composition in each cross section of the absorber of an absorption chiller closer to the equilibrium state of absorption liquid concentration, the absorber has a A plurality of first heat exchangers through which the absorbed liquid flows from the bottom to the top and a plurality of second heat exchangers through which the cooling fluid flows from the bottom to the top are arranged alternately in the vertical direction to improve the operating efficiency of the absorption chiller. The purpose is to improve

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In Fig. 2, 6 has a combustion device 7 for kerosene, gas, etc., which heats and boils an absorption liquid that has absorbed a large amount of refrigerant (hereinafter referred to as concentrated liquid) to gasify and separate the refrigerant. 8 is a rectifier for separating the absorbent components from the rising refrigerant gas; 9 is a rectifier for cooling the gas stream sent from the rectifier 8 with a heat exchanger 10 for final separation of the absorbent components; The liquid separated in the partial condenser 9 is led to the liquid dispersion device 11, and is dispersed from the upper part of the rectifier 8 to form a gas-liquid for separating the refrigerant and the absorbent. Used as part of the contact liquid. 12 is an evaporator incorporating a heat exchanger 13, which is liquefied in a condenser 14, reduced in pressure in a pressure reducing valve 15, and vaporized by giving heat from the heat exchanger 13 to the liquid refrigerant to be sprayed; 18 in the generator 6; The absorption liquid (hereinafter referred to as diluted liquid) in which the refrigerant has been separated and has a low refrigerant concentration is depressurized by the pressure reducing valve 16 and sprayed from the sprayer 17 to absorb the refrigerant gas vaporized by the evaporator 12, thereby causing evaporation. The evaporator 12 is an absorber that continuously absorbs heat from the low-temperature heat source fluid flowing through the heat exchanger 13, and the evaporator 12 and absorber 18 communicate with each other through an opening 19 at the bottom of the absorber 18. ing. 2
Reference numeral 0 designates a solution pump that returns the concentrated liquid that has absorbed the refrigerant in the absorber 18 to the generator 6, and the concentrated liquid pipe 21 having the solution pump 20 has two absorbers installed at the upper and lower parts of the absorber 18. Heat exchangers 22 and 23, which are first heat exchangers that cool the inside of the absorber 18, and a heat exchanger 24 that preheats the concentrated liquid by exchanging heat with the dilute liquid sent from the generator 6 to the absorber 18 are provided. and
The concentrated absorption liquid flows in the direction of the solid arrow.

The rectifier 8 also includes a concentrating section 2 containing a filler 24 that brings the liquid sprayed by the sprayer 11 into gas-liquid contact with the gas flow flowing from the generator 6 toward the condenser 14.
5 and a collection section 27 containing a filler 26 that also promotes gas-liquid contact between the gas flow and the concentrated liquid are vertically installed, and the liquid that has fallen between the fillers 24 of the concentrating section 25 is dispersed. The concentrated liquid sprayed onto the filler 26 by the container 28 flows down the collection section 27 and returns to the generator 6. Furthermore, a cooling fluid such as water or brine is passed through heat exchangers 29 and 30, which are second heat exchangers built into the absorber 18, and a heat exchanger 31 built into the condenser 14, and 1
8 and/or the condenser 14 can be discharged (used in the case of a heat pump) to the outside of the machine.
Cooler 1 formed continuously to this heat exchanger 31
0 has a cooling function for the gas flowing through the dephlegmator 9, and water or brine flows through the respective heat exchangers 29, 31, 3.
0 and 10 as shown by the dotted arrow.

The heat exchangers 29, 30, 22, and 23 are arranged in the vertical positional relationship shown in FIG. 1, so that heat exchanger 29 is at the bottom and heat exchanger 23 is at the top. The absorber 18 is arranged in the absorber 18.
The interior of the refrigerant is configured such that the temperature of the absorption liquid gradually decreases and the concentration of the refrigerant increases as one goes downward from the upper absorption liquid distribution device 17.

FIG. 3 is a longitudinal sectional view of a specific embodiment of the absorption chiller shown in FIG. 2, and the same components as in FIG. 2 are designated by the same number.

In the apparatus shown in FIG. 3, centering on the rectifier 8,
A cylindrical evaporator 12 and an absorber 18 are arranged concentrically. In addition, the heat exchangers 10 and 31 are arranged so that the rectifier 8 is wound around the heat exchangers 22, 23, and 2.
9 and 30 are respectively housed in a spiral shape so as to wrap around the evaporator 12. In the above configuration, the operation will be explained using a heat pump operation as an example.

The refrigerant generated in the generator 6 is transferred to the recovery section 2 of the rectifier.
At step 7, the liquid rises while coming into contact with the concentrated liquid and flows into the concentration section 25. In the concentration section 25, the absorbent component is further removed by contacting the reflux liquid condensed in the demultiplexer 9, and after sufficiently removing the absorbent in the demultiplexer 9, it becomes a gas refrigerant and flows into the condenser 14. It is cooled by the heat exchanger 31 in the condenser, condensed and liquefied through the pressure reducing valve 15, and flows into the evaporator 12.

In the evaporator 12, the pressure is maintained lower than that in the condenser 14, so the liquid refrigerant obtains vaporization heat from the heat source fluid of the heat exchanger 13, evaporates, and passes through the opening 19 to the absorber 1.
8 from the bottom to the top.

Therefore, there are four heat exchangers 2 in the absorber 18.
9, 22, 30, 23 are built-in, sequentially from the bottom,
Since hot water (or brine) and concentrated absorption liquid are distributed so that the temperature becomes high, and the absorption liquid is sprayed from above, the gas refrigerant that has flowed into the absorber 18 first reaches the highest point in the heat exchanger 29 section. The refrigerant is absorbed by the absorbent liquid with a high concentration, and then the concentrated absorbent liquid in the lower part of the absorber 18 is absorbed by the absorbent liquid in the heat exchanger 22 part through which it is passed, and then the heat of the previous heat exchanger 29 and condenser is absorbed. Hot water (or brine) entering via exchanger 31
The refrigerant is absorbed in the 30 parts of the heat exchanger through which the refrigerant is distributed, and finally, in the 23 parts of the heat exchanger through which the concentrated liquid that has passed through the heat exchanger 22 is distributed, it is absorbed into the absorption liquid with the lowest refrigerant concentration.

In this way, all the refrigerant vaporized in the evaporator 12 is absorbed by the absorption liquid and becomes a concentrated liquid, which is then transferred to the pump 2.
The refrigerant is sucked into the refrigerant and refluxed to the generator 6 through the heat exchangers 22, 23, 24 and the recovery unit 27 of the rectifier, where it is heated and separated into a refrigerant and a dilute liquid again. on the other hand,
The hot water (or brine) flowing through the heat exchangers 29, 31, 30, and 10 is heated, and a heat pump operation is performed using the fluid flowing through the heat exchanger 13 as a heat source.

In such an operation, the absorption cooler of the present invention can bring the vapor composition of the horizontal cross section of each level of the absorber 18 close to an equilibrium state with the absorption liquid.

That is, the dilute absorption liquid sprayed from the upper part of the absorber 18 absorbs the refrigerant flowing from the bottom to the top, thereby forming a concentration gradient in which the refrigerant concentration increases sequentially from the top to the bottom. ，
22, 30, and 23 are arranged so that the temperature increases sequentially from the bottom to the top, so the inside of the absorber 18 forms a gradient in which the temperature decreases sequentially from the top to the bottom. .

In this way, in the present invention, by arranging the heat exchangers 22 and 23 so that the absorber 18 is cooled with the absorbent liquid (concentrated liquid) flowing down inside the absorber, the absorbent liquid is inside the absorber 18. It is possible to facilitate the formation of a concentration and temperature gradient of the refrigerant, thereby minimizing the vaporization of the absorbent from the absorbent liquid, and increasing the absorption area in the absorber 18 and increasing the diffusion effect in which the refrigerant is absorbed. In addition, the heat exchanger 24 can be made smaller by recovering heat from the absorber 18 using concentrated liquid.

Therefore, for example, it is possible to suppress the vaporization of the absorbent that occurs when trifluoroethanol (TFE) is used as a refrigerant and N-methyl 2-pyrrolidone or N-butylpyrrolidone is used as an absorbent. The refrigerant diffusion resistance can be suppressed by the absorbed absorbent.

For example, when using the above refrigerant absorbent, if the inside of the absorber has a stepwise temperature and absorption liquid concentration gradient as in the present invention, the concentration of the absorption liquid on the gas phase side (wt% of TFE) will be high. The concentration of the refrigerant is also high at the bottom of the absorber, and the concentration of the absorption liquid on the gas phase side is also low at the top of the absorber, where the concentration of refrigerant is low. Since it can be maintained at each height of the container, the disadvantages of conventional absorption chillers such as the absorbent absorbing refrigerant and the absorbent itself vaporizing and inhibiting refrigerant absorption are eliminated, and it can be used as an absorption heat pump or absorption chiller. This can improve the operating efficiency of the system.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an example of an evaporative absorption shell of a conventional absorption chiller, Fig. 2 is an explanatory diagram showing the configuration of an absorption chiller according to the present invention, and Fig. 3 is an explanatory diagram showing an example of an absorption chiller according to the present invention. It is a longitudinal cross-sectional view showing an example. 6... Generator, 12... Evaporator, 14... Condenser, 18... Absorber, 22, 23, 24... Heat exchanger, 29, 30... Heat exchanger.

Claims (1)

[Claims] 1. A generator that separates the absorbent component from the gas stream heated and vaporized by the generator and converts it into refrigerant gas, a condenser that cools and liquefies the refrigerant gas, and a device that obtains heat from the fluid outside the machine and vaporizes the liquid refrigerant. and an absorber configured to absorb the vaporized refrigerant from the evaporator by dispersing an absorption liquid in which the refrigerant has been separated and the refrigerant components have been reduced in the generator, and these generators, condensers,
The absorber in the circulation cycle of refrigerant and absorption liquid, which consists of an evaporator and an absorber that are connected with piping in a confidential manner,
A plurality of first heat exchangers each having an opening through which the vaporized refrigerant flows in at the bottom, and through which the absorption liquid flowing down in the absorber flows from below to above; and a plurality of second heat exchangers through which the cooling fluid flows from below to above; An absorption chiller characterized in that these are arranged alternately in the vertical direction.