JPH0353551B2 - - 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.

As shown in Fig. 1, an absorption chiller that has been commonly used in the past has an eliminator 1 installed between an evaporator 2 and an absorber 3, and the refrigerant vaporized in the evaporator 2 is transferred to a heat exchanger 4 in the absorber. It has a container body 5 configured to be absorbed by the absorption liquid flowing down the surface. Heat exchangers 4 and 6 built into the absorber 3 and the evaporator 2
is composed of a group of pipes arranged horizontally,
The refrigerant gas vaporized in the evaporator 2 is transferred to the horizontal absorber 3.
The arrangement is such that it flows into and is absorbed by the water. In such a conventional structure, the absorption efficiency of the refrigerant in the absorber 3, the relationship between the absorption liquid concentration and the temperature gradient, etc., were not particularly taken into consideration.

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 cooling device such as , a change to the vapor phase occurred, which was accompanied by a decrease in the absorption capacity of the refrigerant.

The present invention was created in view of these points, and in order to bring the vapor composition in each cross section in the absorber of an absorption chiller close to an equilibrium state with the absorption liquid concentration,
An upper heat exchanger is installed below the absorber dispersion device,
Hot water flows through this heat exchanger from the refrigerant inlet side to the distribution device side, and a lower heat exchanger is provided below the upper heat exchanger, and the fluid from the evaporator is passed through the refrigerant inlet side to this heat exchanger. The main purpose of this is to flow the refrigerant from the side to the upper heat exchanger side, thereby improving the absorption efficiency of the refrigerant in the absorber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In Fig. 2, 7 has a combustion device 8 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. 9 is a rectifier for separating absorbent components from the rising refrigerant gas; 10 is a rectifier for cooling the gas stream sent from the rectifier 9 with a heat exchanger 11 for final separation of the absorbent components; The liquid separated in the dephlegmator 10 is led to the liquid dispersion device 12 and is dispersed from the upper part of the rectifier 9 to form a gas-liquid for separating the refrigerant and the absorbent. Used as part of the contact liquid. 13
has a built-in heat exchanger 14 in which a pipe is wound in a helical shape around the outer circumference of the rectifier 9, and heat is transferred from the heat exchanger 14 to the liquid refrigerant that is liquefied in the condenser 15, reduced in pressure in the pressure reducing valve 16, and sprayed. an evaporator that vaporizes by giving
The refrigerant is separated in the generator 7 and the absorption liquid (hereinafter referred to as diluted liquid) with a low refrigerant concentration is transferred to the pressure reducing valve 1.
The refrigerant gas vaporized in the evaporator 13 is absorbed by reducing the pressure at step 8 and dispersing it from the dispersion device 19, so that the evaporator 13 continuously absorbs heat from the heat source fluid at a low temperature level flowing through the heat exchanger 14. This is an absorber with evaporator 13 and absorber 17.
The evaporator 1 is connected to the evaporator 1 through an open inlet 20 at the bottom.
The absorber 17 is arranged concentrically such that the absorber 17 is located on the outer circumferential side or the inner circumferential side of the absorber 3. 21 is absorber 1
7 is a solution pump that returns the concentrated refrigerant absorbed from the generator 7 to the generator 7, and the concentrated liquid pipe 22 having the solution pump 21 includes a heat exchanger 39 that cools the inside of the dephlegmator 10, and A heat exchanger 23 is provided to preheat the concentrated liquid by exchanging heat with the diluted liquid sent to the vessel 17.

Further, the rectifier 9 is surrounded by a heat insulating material 24, and is thermally separated from the evaporator and absorber disposed outside of the rectifier 9. A concentrating section 26 containing a filler 25 that causes gas-liquid contact with the gas flow flowing from the gas flow toward the condenser 15 side, and a recovery section 28 containing a filler 27 that also promotes gas-liquid contact between the gas flow and the concentrated liquid. The liquid that stands vertically and falls between the filling materials 25 of the concentration section 26 flows down the collection section 28 and returns to the generator 7 together with the concentrated liquid that is sprayed on the filling materials 27 by the sprayer 29. That's what I do.

In addition, the condenser 15 and absorber 17 have a built-in heat exchanger 30 and a heat exchanger (upper heat exchanger) 31 formed into a coil shape that goes around the rectifier 9,
Absorber 17 and/or condenser 15 by flowing water or brine to the heat exchangers 30, 31
heat is discharged outside the machine (used when using a heat pump)
The coil-shaped cooler 11 formed continuously with the heat exchanger 30 has a cooling function in the dephlegmator 10.

The absorber 17 of the present invention is provided with an absorption liquid receiver 32 in the middle part, and the absorption liquid sprayed from above is once collected in the absorption liquid receiver 32 and then dripped downward again. In the heat exchanger (lower heat exchanger) 33 below the absorption liquid receiver 32, the heat source fluid that has exited the evaporator 13 is sequentially passed upward from below, that is, from the opening 20 side to the heat exchanger 31 side, and In the heat exchanger 31 above the absorption liquid receiver 32, hot water heated and raised in temperature by the absorption cooler is made to flow from the bottom to the top, that is, from the opening 20 side to the spraying device 19 side.
As a result, the inside of the absorber 17 can be structured such that the temperature of the absorption liquid decreases and the refrigerant concentration of the absorption liquid increases from the upper absorption liquid distribution device 19 downward.

In the absorption chiller of the present invention having a closed circulation cycle of a refrigerant and an absorbent connected by piping so as to have the equipment configuration as described above, trifluoroethanol is used as a refrigerant and N-methyl-2-pyrrolidone is used as an absorbent. To explain an example in which a heat pump is operated, the Dueling diagram in this case is the third one.
It will look like the figure.

Now, when the temperature at the inflow point A of the heated fluid into the absorber 17 is 35°C and the temperature at the outlet B is 45°C,
The concentration (TFEwt%) of the sprayed absorption liquid is 30wt% in the liquid phase and 75wt% in the gaseous phase at the upper part of the absorber 17, and 44% in the liquid phase and 92% in the gaseous phase near the absorption liquid receiver 32. Below the absorption liquid receiver 32, the temperature and concentration of the absorption liquid further decrease, and near the opening 20 of the absorber 17, the vapor phase reaches about 99%, which is close to the evaporated refrigerant (99.9%) from the evaporator 13. and the inside of the absorber 17 has a continuous temperature gradient from the top to the bottom, in other words, the absorber 1
7 can form a gradient such that the temperature of the refrigerant vaporized in the evaporator 13 decreases toward the inflow side.

In addition, a buffer is attached to the inside of the absorber wall 35, which is 34 in diameter, to allow the refrigerant vapor to rise evenly within the absorber, and the refrigerant flows through the absorber 1.
This is to prevent water from flowing along the walls of the vessel. Such a baffle 34 is preferable in terms of downsizing the heat exchanger 31 and the absorber 17.

In a conventional absorption chiller without such a configuration, for example, when operating a heat pump using the refrigerant-absorbent system as described above, in the vicinity of the refrigerant inlet 20 at the bottom of the absorber 17, the liquid phase is 44 wt%, The gas phase is 92wt%. When refrigerant gas vaporized in the evaporator 13 flows into the absorber 17 in this state, as the refrigerant gas is absorbed by the absorption liquid, a phenomenon occurs in which the absorbent vaporizes, reducing the absorption capacity. This will result in inhibition and eventually stop the refrigerant vaporization in the evaporator 13.

However, according to the absorption chiller of the present invention, hot water is passed through the heat exchanger 31 of the absorber 17 from the opening 20 side to the dispersion device 19 side, and fluid from the evaporator 13 is passed into the heat exchanger 33 from the opening 20 side. Since it flows to the heat exchanger 31 side, the opening 2 where the absorber 17 communicates with the evaporator 13
Near 0, the concentration on the gas phase side of the absorption liquid and the absorber 17
The vaporized refrigerant flowing into the absorber 17 can be brought into a nearly equilibrium state, and a temperature gradient can be formed inside the absorber 17 such that the temperature decreases from the top toward the bottom.
In the opening 20, it is possible to prevent the absorbent from evaporating, and even in an absorption chiller using an absorbent with a relatively high vapor pressure, the cause of inhibition of refrigerant absorption and evaporation can be reduced, and the refrigerant in the absorber can be prevented from evaporating. absorption efficiency can be improved.

In the embodiment of the heat pump described above, a heat source fluid having a temperature of several degrees Celsius is supplied, and hot water at 35° C. can be heated to nearly 60° C. and then supplied outside the machine.

In the above explanation, the heat pump was mainly explained, but heat exchange is performed inside the absorber so as to form a temperature gradient from the absorption liquid distribution device side to the refrigerant inlet side. The idea of arranging a cooling device is also effective when using an absorption chiller for cooling water chillers, refrigerators, ice makers, etc.
In addition, the effects of the present invention can be expected from not only the above-mentioned pyrrolidone-based refrigerant-absorbent but also other refrigerant-absorbents, as long as the vapor pressure of the absorbent is not particularly low.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of an evaporative absorption shell of a conventional absorption chiller, Fig. 2 is a block diagram showing an embodiment of an absorption chiller according to the present invention, and Fig. 3 is a refrigerant absorbent used in the same manner. It is a Duering diagram of . 7-generator, 10-condenser, 13-evaporator, 1
7 - absorber, 19 - absorption liquid distribution device, 20 - opening (inlet), 31, 33 - heat exchanger.

Claims (1)

[Claims] 1 A generator that heats the absorption liquid and separates the absorbent components from the vaporized gas stream to create refrigerant gas, a condenser that cools and liquefies the refrigerant gas, and a device that obtains heat from the fluid outside the machine to vaporize the liquid refrigerant. an evaporator, a dispersion device for dispersing the absorption liquid from the generator, and an absorber provided below the dispersion device and having an inlet for the refrigerant from the evaporator, the generator, the condenser, In an absorption chiller in which an evaporator and an absorber are airtightly connected via piping to form a circulation cycle of refrigerant and absorbent, the device is installed below the dispersion device of the absorber, and is directed from the inlet side to the dispersion device side. The heat exchanger includes an upper heat exchanger through which fluid flows, and a lower heat exchanger which is provided below the upper heat exchanger and through which fluid from the evaporator flows from the inlet side to the upper heat exchanger side. Features an absorption chiller.