JP2003075013A - Absorption refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the absorption accelerating effect of an absorber. SOLUTION: An absorption refrigerating machine is provided with a concentration detecting means 150 which detects the concentration of a surface-active agent contained in a refrigerant sprayed upon an evaporator tube and concentration adjusting means 151 and 152 which adjust the concentration of the surface- active agent so that the concentration may become a prescribed reference value or higher based on the detected results of the detecting means 150.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerator, and more particularly to a means for promoting absorption in an absorber.

[0002]

2. Description of the Related Art An absorption refrigerating machine sprays a liquid refrigerant on an evaporator tube through which cold water flows and an absorbent tube (for example, lithium bromide solution) sprays on an absorber tube through which cold water flows. And an absorber that absorbs the vapor of the liquid refrigerant flowing from the evaporator by the hygroscopic force of the absorbing liquid. The lower the absorption liquid used in the absorber is, the better the vapor of the liquid refrigerant is absorbed. The absorber tube is provided for the purpose of cooling the absorbing liquid with cold water flowing inside. In this absorption refrigerator, in order to promote absorption in the absorber, a surfactant such as alcohol is mixed in the vapor of the liquid refrigerant, and the surfactant is sent to the gas-liquid interface of the absorber. ing.

[0003]

However, in the conventional absorption refrigerator, it is difficult to properly control the concentration of the alcohol, so that the absorption promoting effect in the absorber cannot be obtained stably and sufficiently. It was happening. In view of such a situation, an object of the present invention is to provide an absorption refrigerator that can stably and sufficiently obtain the absorption promoting effect in the absorber.

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, an eliminator is provided by spraying an absorbing liquid on an evaporator tube in which cold water flows and a refrigerant containing a surfactant, and an absorber tube in which cold water flows. An absorption refrigerating machine comprising an absorber that absorbs the vapor of the refrigerant flowing from the evaporator via the absorber, and detects the concentration of a surfactant in the refrigerant sprayed to the evaporator tube. A concentration detecting unit and a concentration adjusting unit that adjusts the concentration of the surfactant so as to be equal to or higher than a predetermined reference concentration based on the detection result of the concentration detecting unit. According to this configuration, the concentration of the surfactant is adjusted to be equal to or higher than the reference concentration.

Alcohol can be used as the surfactant. In addition, the standard concentration is 1500p
It is desirable to set the value to pm or more, preferably 2000 ppm.

It is possible to add means for taking out the surface-active agent in a state of being floated and separated from the pool of the refrigerant, and means for spraying the taken-out surface-active agent from the eliminator into the refrigerant vapor. According to this configuration, the absorptivity of the absorber can be further promoted by utilizing the surfactant that floats in the pool of the refrigerant. As a means for spraying the surfactant, for example, an ultrasonic atomizer can be used. In this case, after extracting the surfactant separated from the refrigerant and staying, it is sprayed with an ultrasonic atomizer and placed on the vapor of the evaporator, so that it flows down to the tube group (heat transfer tube group) of the absorber. The absorption solution can be supplied.

In order to vibrate the absorbing liquid flowing down between the peripheral surfaces of the absorber tubes and between the absorber tubes, a sound wave generating means for sending a sound wave toward them can be further provided. According to this structure, the absorptivity of the absorber is further improved by improving the convection property of the absorbing liquid due to the vibration by the sound wave.

As means for spraying the absorbing liquid on the absorber tube, a tray having an absorbing liquid flowing hole arranged in the axial direction of the tube is used, and the absorbing liquid flowing hole is arranged in the axial direction. The arrangement interval can be set to 80 to 120% of the diameter of the absorber tube. According to this configuration, the water absorption of the absorber tube is improved because the water supply of the absorber tube is improved.

The longitudinal array spacing of the absorber tubes is
It is desirable to set it to 20 to 30 mm. According to this configuration, the water absorption of the absorber tube is improved because the water supply of the absorber tube is improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, with reference to FIG. 1, the outline of the configuration and operation of an absorption refrigerator to which the present invention is applied will be described. Note that FIG. 1 shows the system configuration, and does not show the actual mechanical arrangement position of each device.

In FIG. 1, a refrigerant (water in this example) 120 containing a surfactant (alcohol in this example) stored in the bottom of the evaporator 110 is extracted by a liquid refrigerant pump 111, and then the evaporator is extracted. It is sprayed on the heat exchange device 113 from the sprayer 112 arrange | positioned inside 110. The refrigerant 120 evaporates by exchanging heat with the cold water flowing through the evaporator tubes in the process of flowing down along the outer surfaces of a large number of evaporator tubes (heat transfer tubes) constituting the heat exchange device 113. . The cooled cold water 121 is supplied to a cooling load (not shown).

Refrigerant vapor 12 evaporated in the evaporator 110
2 flows into the absorber 114 through the eliminator 141. Then, this refrigerant vapor 122 is absorbed by the absorber 11
4 to the heat exchanger 116 from the sprinkler 115 arranged at the top of
Is absorbed by a liquid absorbent such as a concentrated solution of lithium bromide to form a dilute solution 123, which is stored at the bottom of the absorber 114. The reaction heat generated when the refrigerant vapor 122 is absorbed by the absorbing liquid is extracted to the outside by the cooling water flowing through the many absorber tubes (heat transfer tubes) forming the heat exchanger 116.

The dilute solution 12 accumulated at the bottom of the absorber 114
After being extracted by the solution pump 117, 3 is heated by the low temperature heat exchanger 118. Then, a part of the overheated dilute solution is branched and introduced into the low pressure regenerator 133, and the rest is
After being heated by the high temperature heat exchanger 119, the high pressure regenerator 131
Flows into. The dilute solution that has flowed into the high pressure regenerator 131 is stored in the bottom of the regenerator while the heat transfer tube 132
It is heated by the heat source vapor flowing through the inside of the container, and a part of the contained refrigerant is evaporated to become a concentrated solution 125.

The concentrated solution 125 is extracted and flows into the high temperature heat exchanger 119, where it is cooled by exchanging heat with the dilute solution and then merged with the concentrated solution 127 extracted from the low pressure regenerator 133 to obtain a low temperature. It flows into the heat exchanger 118. Then, it is cooled again by exchanging heat with the dilute solution in the low temperature heat exchanger 118, and thereafter, the absorber 11
4 and is sprayed from the sprayer 115 to the heat exchanger 116.

In the high pressure regenerator 131, the concentrated solution 1
The refrigerant vapor 126 evaporated from 25 is extracted and introduced into the tube 134 arranged at the bottom of the low pressure regenerator 133. The introduced refrigerant vapor passes through the tube 134, and in the process of flowing through the tube 134, the concentrated solution 127 outside the tube 134.
The liquid refrigerant 128 is cooled by heat exchange with the liquid refrigerant 128. Then, the refrigerant vapor 12 evaporated from the heated concentrated solution 127
9 enters condenser 135 through eliminator 142.

On the other hand, the heat-refrigerant 128 liquefied in the tube (heat transfer tube) 134 is sprayed to the heat exchange device 137 from the sprayer 136 arranged in the upper part of the condenser 135. Then, in the process of descending in the condenser 135, it flows down the outer surfaces of a large number of tubes (heat transfer tubes) that constitute the heat exchange device 137 along with the refrigerant vapor 129, and in the flow down process,
The refrigerant vapor 129 is condensed by being cooled by the cooling water flowing through the tube.

The refrigerant 130 accumulated at the bottom of the condenser 135
After being throttled by passing through the expansion valve 139,
It is ejected from a nozzle 140 arranged in the upper inside of the evaporator 110, a part of which is flash-evaporated, and the rest is stored in the bottom of the evaporator 110.

By the way, from the evaporator 110 to the gas-liquid separator 1
Refrigerant vapor 122 flowing into the absorber 114 via 41
Causes the alcohol contained therein to condense, resulting in non-uniform surface tension at the gas-liquid interface of the absorber 114, that is, imbalance in the amount of absorbed vapor. This imbalance causes so-called Marangoni convection in the liquid phase portion of the absorber 114, and consequently promotes absorption of water vapor in the absorber 114.

The absorption promoting action of alcohol depends on the concentration of the alcohol. However, at the bottoms of the evaporator 110 and the condenser 135, the refrigerants 120 and 130 are separated into water and alcohol, and the alcohol stays in layers on the surface of the water. There is a possibility that the alcohol concentration in the sprayed refrigerant becomes insufficient and the absorption performance of the absorber 114 deteriorates.

Therefore, in the embodiment of the present invention,
The concentration sensor 150 detects the alcohol concentration of the refrigerant dispersed in the heat exchanger 113 of the evaporator 110, specifically, the alcohol concentration of the refrigerant extracted by the pump 111 from the bottom of the evaporator 110, and the detected alcohol. The controller 151 compares the density with a reference value.

When the detected alcohol concentration is lower than the reference value, the controller 151 opens the valve 152 to supplement the alcohol supplied to the sprayer 112 with alcohol. Therefore, according to this embodiment, the alcohol concentration of the refrigerant dispersed in the tubes of the heat exchanger 113 of the evaporator 110 is constantly maintained at a reference value or higher, and the absorption of water vapor by the absorber 114 is stable and effective. Be promoted to.

As a result of experiments, it has been found that an alcohol concentration of at least 1500 ppm or more is required to promote the absorbability of the absorber 114 in the absorption refrigerator having the above structure. Therefore, the above standard value is practically 1
It may be set to 500 ppm, but as a result of further research, it was found that the alcohol concentration for promoting absorption more sufficiently is 2000 ppm or more. Therefore,
In this embodiment, the reference value is set to 1500 ppm, more preferably 2000 ppm.
If the alcohol concentration is maintained above 2000ppm,
The absorption promoting performance was about 2.5 times that of the case where no alcohol was added, and about 1.5 times that at the same concentration of 1500 ppm. Instead of adding alcohol, the refrigerant stored at the bottom of the evaporator 110 and / or the bottom of the condenser 135 is diffused by an appropriate diffusing means to increase the alcohol concentration of the refrigerant extracted from those bottoms. It is also possible to configure so that it is made to.

As described above, alcohol is retained in the upper layers of the refrigerants 120 and 130 stored at the bottoms of the evaporator 110 and the condenser 135. In the refrigerator according to this embodiment, the alcohol retained in the upper layers of the refrigerants 120 and 130 is extracted by the pumps 153 and 154, respectively, and this is supplied to the ultrasonic atomizer 155 arranged in the gas-liquid separator 141. I am trying to do it.

The ultrasonic atomizer 155 is a gas-liquid separator 141.
Alcohol is sprayed in the flow of the refrigerant vapor 122 passing through or at the gas-liquid interface of the absorber 114, so that the absorption of the refrigerant vapor in the absorber 114 is further promoted. Although not shown, in order to vibrate the peripheral surface of each absorber tube 113 and the absorbing liquid flowing down between the absorber tubes 113, an acoustic speaker and an ultrasonic transducer that send out sound waves toward them. Absorber 1
It is also possible to arrange it in 14 places. By providing such a vibrating means, the convection of the absorbing liquid in the absorber 114 is better performed, and the absorption of the refrigerant vapor is further promoted.

By the way, as shown in FIG.
When the sprayer 115 provided in 4 is a tray, the absorbing liquid stored in the tray-type spreader 115 is placed on the tube (absorber tube) 116a of the heat exchanger 116 through the hole 115a provided at the bottom thereof. In a column shape. Then, the upper tube 116a and the lower tube 116a
Even in the interval, the absorbing liquid flows down in a columnar shape. Evaporator 110
The refrigerant vapor 122 from the above flows in the direction indicated by the white arrow and is absorbed by the liquid film of the absorbing liquid formed on the peripheral surface of the absorber tube 116a. If the arrangement interval L1 of the tubes 116a in the axial direction is not appropriate, the absorbing liquid will not be absorbed by the tubes 116a.
No liquid film is formed on the entire peripheral surface of the tube, that is, the wettability (irrigation) of the peripheral surface of the tube 116a by the absorbing liquid is reduced.

Therefore, in this embodiment, the arrangement interval L1 of the holes 115a is set to 80 to 120% of the diameter of the tube 116a (for example, 19.05 mm) so that the absorbing liquid may surround the tube 116a. A liquid film is formed on the entire surface. In this way, the tube 11
If the liquid film of the absorbing liquid is formed on the entire peripheral surface of 6a, the absorbing property of the refrigerant vapor 122 is improved, and the heat exchange efficiency of the heat exchanger 116 constituting the tube 116 is also improved.

On the other hand, the absorbing liquid flowing down in the columnar shape is affected by the vapor flow 122 (flows biased in the direction of action of the vapor flow), and this influence becomes greater as the vertical arrangement interval of the tubes 116a group becomes larger. Become. Then, when the deviation of the flow-down position of the absorbing liquid becomes larger than a certain amount, the wettability (irrigation) of the peripheral surface of the tube 116a by the absorbing liquid is lowered. Therefore, in this embodiment,
Set the vertical arrangement interval L2 of the absorber tubes 116a group to 20.
It is set to -30 mm. According to this configuration, since the absorbing liquid flows down in the range of about 15 ° to the left and right with the apex of the tube 116a as the center, the absorbing liquid flows on the peripheral surfaces on both sides of the tube 116a. As a result, the heat transfer performance of the tube 116a is improved by about 10% as compared with the case where the distance L2 is set to a size outside the above range.

[0028]

According to the present invention, the concentration detecting means for detecting the concentration of the surfactant in the refrigerant sprayed on the evaporator tube, and the concentration of the above surfactant based on the detection result of the concentration detecting means. Since the concentration adjusting means for adjusting the concentration to be equal to or higher than the predetermined reference concentration is provided, the concentration of the surfactant is always maintained at the reference concentration or higher, and the absorption of the refrigerant vapor by the absorber is stable and effective. Be promoted.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an absorption refrigerator according to the present invention.

FIG. 2 is a perspective view illustrating the flow-down mode of the absorbing liquid from the tray.

[Explanation of symbols]

110 evaporator 111, 117, 153, 154 pumps 112,115 sprayers 113,116 heat exchanger 116a absorber tube 114 absorber 120 refrigerant 121 cold water 122 Refrigerant vapor 135 condenser 150 concentration sensor 151 controller 152 valve 155 ultrasonic atomizer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiro Kawada             2-1-1 Niihama, Arai-cho, Takasago, Hyogo Prefecture             Takasago Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Yoichiro Iriya             2-1-1 Niihama, Arai-cho, Takasago, Hyogo Prefecture             Takasago Laboratory, Mitsubishi Heavy Industries, Ltd. F term (reference) 3L093 CC00 DD08 EE09 EE21 GG00                       HH00 JJ01 KK00 LL13 LL18                       LL20

Claims (7)

[Claims] 1. An evaporator for spraying a refrigerant containing a surfactant on an evaporator tube through which cold water flows, and an absorbent liquid for an absorber tube through which cold water flows, and then flows from the evaporator through an eliminator. An absorption refrigerating machine comprising an absorber that absorbs the vapor of the refrigerant by the absorbing liquid, wherein the concentration detecting means detects the concentration of a surfactant in the refrigerant dispersed in the evaporator tube, and the concentration detecting means. An absorption refrigerating machine comprising: a concentration adjusting unit that adjusts the concentration of the surfactant so as to be a predetermined reference concentration or more based on the detection result of the unit. 2. The absorption refrigerator according to claim 1, wherein the surfactant is alcohol, and the reference concentration is set to a value of 1500 ppm or more. 3. A means for taking out the surface-active agent in a floating and separated state from the pool of the refrigerant, and a means for spraying the taken-out surface-active agent from the eliminator into the refrigerant vapor. Item 1. The absorption refrigerator according to Item 1 or 2. 4. The absorption refrigerator according to claim 3, wherein an ultrasonic atomizer is used as a means for atomizing the surfactant. 5. A sound wave generating means for sending a sound wave toward the peripheral surface of each absorber tube and for vibrating the absorbing liquid flowing down between the absorber tubes, is further provided. Item 5. The absorption refrigerator according to any one of items 1 to 4. 6. A tray having an absorbing liquid flow-down hole arranged in an axial direction of the tube is used as a means for spraying the absorbing liquid onto the absorber tube, and the axis line of the absorbing liquid flow-down hole is used. The absorption refrigerator according to any one of claims 1 to 5, wherein the arrangement interval in the direction is set to 80 to 120% of the diameter of the absorber tube. 7. The absorption refrigerator according to claim 6, wherein the vertical arrangement interval of the absorber tubes is set to 20 to 30 mm.