JP4376108B2 - Absorption refrigerator - Google Patents

Description

  The present invention includes a regenerator, a condenser, an absorber, an evaporator, and a refrigeration medium take-out pipe for taking out a refrigeration medium such as cold water from the evaporator, and further, a refrigeration medium taken out from the refrigeration medium take-out pipe The present invention relates to an absorption chiller configured to adjust the amount of absorbed liquid after absorption of refrigerant returned from the absorber to the regenerator in accordance with the take-out load.

  This type of absorption refrigerator is conventionally provided with a high-temperature regenerator and a low-temperature regenerator, and is supplied from the absorber to the low-temperature regenerator by the absorbent after evaporation of the refrigerant supplied from the high-temperature regenerator to the absorber. It is comprised so that the absorption liquid after refrigerant | coolant absorption may be heated.

  In addition, a temperature detector that detects the temperature of the cold water is attached to the evaporator pipe (freezing medium take-out pipe) for taking out the cold water, and the load signal detected by the temperature detector is input to the regulator and detected by the temperature detector. The amount of fuel gas or heavy oil supplied to the heating means provided in the high temperature regenerator is increased or decreased by changing the opening of the control valve based on the load signal.

  Furthermore, the control valve is equipped with a potentiometer for detecting the opening degree, the inverter is operated based on the opening degree signal of the control valve, and the rotational speed of the absorption liquid pump and the intermediate concentration absorption liquid pump is changed, It adjusts so that it may become the optimal circulation amount of absorption liquid according to load (refer to patent documents 1).

In addition, as the absorber, a large number of heat transfer tube groups that allow cooling water to pass through are arranged horizontally in multiple rows and stages, and the absorbent after evaporation of the refrigerant is sprayed from above the heat transfer tube groups, and each heat transfer tube A liquid film of the absorbing liquid is formed on the outer surface, the absorbing liquid after evaporation of the refrigerant is cooled by cooling water, and the refrigerant evaporated by the evaporator is absorbed by the absorbing liquid after evaporation of the refrigerant. (See Patent Document 2).
JP-A-1-98864 JP 2001-165530 A

  However, in the above-mentioned conventional example, as the load becomes a partial load and the circulating amount of the absorbing liquid is reduced, the amount of the absorbing liquid after evaporation of the refrigerant sprayed from the spraying mechanism in the absorber, the so-called liquid film flow rate decreases. To do.

  As a result, as shown in the side view of the absorber of FIG. 6 (b), the diffusibility in the longitudinal direction of the heat transfer tube 32 decreases, and the area wetted by the absorbing liquid, that is, the wetted area decreases, There was a drawback that so-called wettability was lowered, the refrigerant absorption amount was reduced, and the partial load performance of the absorber was lowered.

The present invention has been made in view of such circumstances, and the invention according to claim 1 is capable of rationally increasing the refrigerant absorption amount regardless of the decrease in the circulation flow rate of the absorbing liquid. It is intended to allow prevent deterioration of partial load performance of the absorber by suppressing the decrease of the liquid film flow rate to a particular heat transfer tube, the invention according to claim 2, more rationally much refrigerant absorption The purpose is to be able to.

In order to achieve the above-described object, the invention according to claim 1
A regenerator that regenerates the refrigerant by heating the absorbent containing the refrigerant;
A condenser for supplying a refrigerant regenerated and evaporated in the regenerator to condense and liquefy;
An absorber for supplying an absorbent after evaporation of the refrigerant from the regenerator;
An evaporator connected to the absorber and supplying the refrigerant condensed and liquefied by the condenser and evaporating the refrigerant by absorbing the refrigerant by the absorber;
A refrigeration medium take-out pipe for taking out a refrigeration medium attached to the evaporator and cooled by latent heat of vaporization in the evaporator;
An absorbing liquid return pipe connected to the absorber and the regenerator to return the absorbing liquid that has absorbed the refrigerant to the regenerator;
An absorbing liquid circulation amount adjusting means for adjusting the amount of the absorbing liquid after absorbing the refrigerant returned from the absorber to the regenerator in accordance with the taking-out load of the refrigerating medium taken out from the refrigerating medium take-out pipe;
In order to constitute the absorber, a heat transfer tube group that is provided in a multi-row and multi-stage horizontally and passes cooling water inside,
A spraying mechanism that is connected to the absorber and the regenerator and sprays the absorbent after evaporation of the refrigerant from above the heat transfer tube group,
In the absorption refrigerator with
A circulation amount detecting means for detecting a circulation amount of the absorbing liquid;
Multiple cocoons that spray the absorption liquid in a specific heat transfer tube group,
An on-off valve for changing the number of the sprinkles for spraying the absorbing liquid;
Based on the circulation amount of the absorption liquid detected by the circulation amount detection means, a heat transfer tube group for spraying the absorption liquid after evaporation of the refrigerant is selected so that the liquid film flow rate in the heat transfer tube of the absorber is within a predetermined range. A liquid film flow rate control means , and
The liquid film flow rate control means,
Absorbing liquid for adjusting the liquid film flow rate Γ in the range of 0.006 ≦ Γ ≦ 0.02 based on the correlation between the liquid film flow rate Γ (kg / s · m) in the heat transfer tube of the absorber and the amount of refrigerant absorbed. A liquid film flow rate table for pre-correlating and storing the circulation amount of
Based on the circulating amount of the absorbing liquid detected by the circulating amount detecting means, the number of the soot corresponding to the circulating amount is obtained from the liquid film flow rate table, and a valve selection is performed by selecting a predetermined valve from the on-off valve and closing it. Means .
This is because, in both cases where the liquid film flow rate Γ is less than 0.006 and exceeds 0.02, the refrigerant absorption amount decreases as shown in the graph of FIG.

(Action / Effect)
According to the configuration of the absorption refrigerator of the invention according to claim 1 , when the load decreases and the amount of the absorbent that is circulated decreases, the absorbent is concentrated to a specific heat transfer tube group, The liquid film flow rate Γ in the specific heat transfer tube group can be maintained in a range in which the refrigerant absorption amount that satisfies 0.006 ≦ Γ ≦ 0.02 does not decrease.

  Therefore, regardless of the change in the circulating amount of the absorbing liquid, in the heat transfer tube group to which the absorbing liquid is supplied, the liquid film flow rate is maintained within a range in which the refrigerant absorbing amount that satisfies 0.006 ≦ Γ ≦ 0.02 does not decrease. Therefore, the amount of refrigerant absorbed can be increased reasonably, and the decrease in the partial load performance of the absorber can be prevented by suppressing the decrease in the liquid film flow rate for the specific heat transfer tube regardless of the decrease in the circulating flow rate of the absorbing liquid.

In order to achieve the above-described object, the invention according to claim 2
In the absorption refrigerator according to claim 1 ,
A heat transfer tube group closer to the evaporator is preferentially selected.

(Action / Effect)
According to the configuration of the absorption refrigerator of the invention according to claim 2 , the liquid film flow rate is maintained in a certain range in the heat transfer tube group on the side close to the evaporator regardless of the change in the circulating flow rate of the absorbing liquid, and the evaporator Therefore, the refrigerant can be easily absorbed, and the amount of refrigerant absorbed can be increased reasonably.

According to the absorption chiller of the invention according to claim 1, when the load decreases and the amount of the absorbing liquid circulated decreases, the absorbing liquid is concentrated in a specific heat transfer tube group, The liquid film flow rate Γ in the heat transfer tube group can be maintained in a range in which the refrigerant absorption amount that satisfies 0.006 ≦ Γ ≦ 0.02 does not decrease .
Therefore, regardless of the change in the circulating amount of the absorbing liquid, in the heat transfer tube group to which the absorbing liquid is supplied, the liquid film flow rate is maintained within a range in which the refrigerant absorbing amount that satisfies 0.006 ≦ Γ ≦ 0.02 does not decrease. Therefore, the amount of refrigerant absorbed can be increased reasonably, and the decrease in the partial load performance of the absorber can be prevented by suppressing the decrease in the liquid film flow rate for the specific heat transfer tube regardless of the decrease in the circulating flow rate of the absorbing liquid.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an overall schematic configuration diagram showing an embodiment of an absorption refrigerator according to the present invention, which is configured to operate with a working fluid using water as a refrigerant and lithium bromide solution as an absorption liquid. A low-temperature regenerator 1 that regenerates the refrigerant by heating the absorption liquid containing the refrigerant and a condenser 2 that condenses and liquefies the regenerated and evaporated refrigerant are provided in communication with each other.

  Below the low-temperature regenerator 1 and the condenser 2, the evaporator 3 and the absorber 4 are provided in communication with each other.

  The condenser 2 and the evaporator 3 are connected via a first refrigerant liquid pipe 5, and the refrigerant liquid condensed and liquefied by the condenser 2 is supplied to the evaporator 3.

  A refrigerant liquid spray nozzle 6 is provided in the upper part of the evaporator 3, and the refrigerant liquid spray nozzle 6 and the lower part of the evaporator 4 are connected via a second refrigerant liquid pipe 8 having a refrigerant liquid pump 7 interposed therebetween. In addition, a refrigeration medium take-out pipe 9 is provided below the refrigerant liquid spraying nozzle 6 to evaporate the refrigerant by absorbing the refrigerant by the absorber 4, and to supply a refrigeration medium such as water and brine by the latent heat of evaporation accompanying the evaporation. It is configured to cool and take out.

  A cooling water pipe 10 from a cooling tower (not shown) is provided from the absorber 4 to the condenser 2.

  The absorber 4 and the high-temperature regenerator 11 are connected via the first pipe 13, the low-temperature solution heat exchanger 14, the intermediate pipe 15, the high-temperature solution heat exchanger 16, and the second pipe 17 interposed with the absorption liquid pump 12. Connected.

  The high temperature regenerator 11 and the low temperature regenerator 1 are connected via a third pipe 18, a high temperature solution heat exchanger 16, and a fourth pipe 19.

  The low-temperature regenerator 1 and an absorbing liquid spraying nozzle 20 as a spraying mechanism provided on the upper part of the absorber 4 are connected via a fifth pipe 21, a low-temperature solution heat exchanger 14, and a sixth pipe 22. .

  The high temperature regenerator 11 is provided with a burner 23 as a heating means, and an upper part of the high temperature regenerator 11 and the condenser 2 are provided with a steam pipe 24 provided in a state in which the refrigerant in the low temperature regenerator 1 can be heated and evaporated. Connected through. That is, the steam flowing in the evaporation pipe 24 is configured as a heating source for the low temperature regenerator 1.

  A configuration for returning the absorbing liquid that has absorbed the refrigerant, consisting of the first pipe 13, the intermediate pipe 15, and the second pipe 17, to the high-temperature regenerator 11 from the absorber 4 is referred to as an absorbing liquid return pipe.

  With the above configuration, the high-temperature solution heat exchanger 16 and the low-temperature solution heat exchanger 14 can heat the absorption liquid after absorption of the refrigerant by the absorption liquid after evaporation of the refrigerant.

  The first pipe 13 is provided with a first thermometer 25 for measuring the temperature of the absorbing liquid after absorption of the refrigerant, and the sixth pipe 22 is a second temperature for measuring the temperature of the absorbing liquid after evaporation of the refrigerant. A total 26 is provided.

  In addition, an inverter 27 that adjusts the discharge capacity according to the frequency is attached to the absorbent pump 12, and a circulation amount detection means 28 that senses the output frequency and detects the circulation amount of the absorbent is attached to the inverter 27. Has been.

  Each of the first and second thermometers 25 and 26 is connected to a first controller 29 as an absorbing liquid circulation amount adjusting means as shown in the block diagram of the circulation amount control system in FIG. An inverter 27 is connected to the first controller 29.

  The first controller 29 includes a density width calculation unit 30 and a comparison unit 31.

  In the concentration width calculation means 30, based on the difference between the temperature of the absorbent after absorption of refrigerant measured by the first thermometer 25 and the temperature of the absorption liquid after evaporation of refrigerant measured by the second thermometer 26. Thus, the concentration range of the absorbing liquid containing the refrigerant is calculated.

  The comparison means 31 compares the density width calculated by the density width calculation means 30 with the set value, and outputs an increase signal when the calculated density width is larger than the set value, while the calculated density width is smaller than the set value. When it is small, a decrease signal is output.

  In the inverter 27, the frequency is increased in response to the increase signal from the comparison means 31, the discharge capacity of the absorption liquid pump 12 is increased to increase the circulating flow rate of the absorption liquid, while the frequency is increased in response to the decrease signal. From the absorber 4 so as to reduce the discharge capacity of the absorption liquid pump 12 to reduce the circulating flow rate of the absorption liquid, that is, according to the extraction load of the refrigeration medium taken out from the refrigeration medium extraction pipe 9. The amount of the absorption liquid after absorption of the refrigerant returned to the high-temperature regenerator 11 (circulation flow rate of the absorption liquid) is adjusted. In order to adjust the circulating flow rate of the absorbing liquid, a flow rate adjusting valve may be provided on the downstream side of the absorbing liquid pump 12, and the valve opening degree may be adjusted.

  As shown in the cross-sectional view of the main part of the absorber and the evaporator of FIG. 3 and the side view of FIG. 4 (the XX line arrow view of FIG. 3), the absorber 4 allows cooling water to pass therethrough. A large number of heat transfer tubes 32 are provided horizontally in rows and multiple stages across the inlet header 33 and the outlet header 34, and the absorbing liquid spray nozzle 20 is provided above the heat transfer tube 32 group.

  The absorbing liquid spraying nozzle 20 is configured by providing a spraying pipe 36 at a predetermined interval in the longitudinal direction (the same distance as the heat transfer pipe 32) at the bottom of the flange 35. Further, a branch pipe 37 branched from the sixth pipe 22 for supplying the absorbent after evaporation of the refrigerant is provided in correspondence with the upper side of each bowl 35, and the evaporator 3 is provided between the adjacent branch pipes 37. First, second, and third on-off valves 38, 39, and 40 are provided in this order from the side far from the center.

  The evaporator 3 is also structurally similar to the absorber 4, and is provided with a large number of cold water heat transfer tubes 41 for flowing cold water as a refrigeration medium horizontally and in rows, and the group of cold water heat transfer tubes 41. The refrigerant liquid spraying nozzle 6 is provided above the nozzle.

  The refrigerant liquid spraying nozzle 6 is configured by providing a refrigerant liquid spraying pipe 43 at a predetermined interval in the longitudinal direction (the same interval as that of the cold water heat transfer pipe 41) at the bottom of the flange 42. Further, a branch pipe 44 branched from the second refrigerant liquid pipe 8 for supplying the refrigerant liquid is provided in correspondence with the upper side of each flange 42.

  As shown in the block diagram of the liquid film flow rate control system in FIG. 2B, the circulation amount detection means 28 is connected to a second controller 45 as a liquid film flow rate control means. In addition, the first, second and third on-off valves 38, 39, 40 are connected.

  The second controller 45 is provided with a liquid film flow rate table 46 and a valve selection means 47.

  In the liquid film flow rate table 46, the circulation amount of the absorption liquid and the number of the tubs 35 to which the absorption liquid is to be supplied are correlated and stored in advance.

  That is, when the correlation between the liquid film flow rate Γ (kg / m · s) and the refrigerant absorption is obtained for the three types of specimens A, B, and C as the heat transfer tube 32, the result shown in the graph of FIG. 5 is obtained. Based on this result, the number of ridges 35 necessary to make Γ (kg / s · m) in the range of 0.006 ≦ Γ ≦ 0.02 is obtained.

  The specimen A is a so-called flute tube whose surface shape is zigzag in cross-sectional view, the specimen B is a so-called cross knurled pipe whose surface is knurled in a mesh shape, and the specimen C is Each tube with a smooth surface was used. D indicates a theoretical value. Based on the result of this graph, in any of the three types of specimens A, B, and C, the refrigerant absorption amount is large in the range of 0.006 ≦ Γ ≦ 0.02, and the refrigerant absorption amount decreases outside the range. Because we can find out.

  The valve selection means 47 obtains the number of the corresponding rods 35 based on the circulation amount of the absorbing liquid detected by the circulation amount detection means 28, and in the case of three, only the first on-off valve 38 is closed. A signal is output, and the absorbing liquid is supplied from three bottles 35 close to the evaporator 3. In the case of two, a closing signal is output to the first and second on-off valves 38 and 39, and the absorbing liquid is supplied from the two bottles 35 close to the evaporator 3. In the case of one, a closing signal is output to the first, second and third on-off valves 38, 39 and 40 so that the absorbing liquid is supplied from only one bottle 35 close to the evaporator 3. It has become.

  According to the change in the circulation amount of the absorbing liquid, comprising the circulation amount detection means 28, the first, second and third on-off valves 38, 39, 40 and the second controller 45 as the liquid film flow rate control means. A mechanism for selecting the heat transfer tube 32 group for spraying the absorbing liquid is referred to as a liquid film flow rate adjusting mechanism.

  When the formation state of the liquid film according to the above-described embodiment was observed, as shown in the side view of the absorber in FIG. 6A, the absorbing liquid was supplied from the eaves 35 regardless of the change in the circulating amount of the absorbing liquid. A liquid film of the absorbing liquid was formed almost uniformly on the surface of the heat transfer tube 32. On the other hand, in the case of the conventional example, as shown in the side view of the absorber of the conventional example in FIG. 6B, as the circulating amount of the absorbing liquid decreases, a portion that is not covered with the absorbing liquid occurs. As a result, it was found that the wetted area is reduced, the wettability is reduced, and the refrigerant absorption is reduced.

  Further, when a comparative experiment was performed on the correlation between the load factor and the coefficient of performance (COP), the result shown in the graph of FIG. 7 was obtained.

  As an experiment, when the circulation amount of the absorption liquid is controlled according to the load, and the liquid film flow rate is controlled based on the change in the circulation volume of the absorption liquid, J, the absorption liquid circulation In the case of the comparative experimental example 1 in which only the configuration for controlling the amount according to the load was adopted, and in the case of the comparative experimental example 2 in which the circulating amount of the absorbing liquid was not controlled according to the load, the test was performed for each of J2. . The temperature of the cooling water supplied to the absorber 4 was set to a constant temperature (32 ° C.).

  From the above results, in the case of Comparative Experimental Examples 1 and 2, the coefficient of performance (COP) decreased as the load factor became lower than 0.5 in all cases. In the case J according to the example, it was clear that the coefficient of performance (COP) can be increased even when the load factor is lower than 0.5, and the partial load performance is extremely excellent.

  In the above-described embodiment, when the circulation amount of the absorbing liquid is reduced, the heat transfer tube 32 on the side close to the evaporator 3 is selected preferentially to spray the absorbing liquid, and the refrigerant is absorbed by the absorbing liquid. The advantage is that the amount can be increased.

  The working fluid of the absorption refrigerator according to the present invention is not limited to water as a refrigerant and lithium bromide solution as an absorbing liquid, for example, water or alcohol as a refrigerant, lithium iodide, lithium chloride, zinc chloride, etc. Various working fluids, such as a solution of a halogenated salt of an absorption solution, a solution of a halide added with lithium nitrate as an absorption solution, an ammonia solution as a refrigerant, and water as an absorption solution Is applicable.

  In the above-described embodiment, an absorption refrigerator having the low temperature regenerator 1 and the high temperature regenerator 11 is shown. However, the present invention may be an absorption refrigerator having a single regenerator.

  Further, as the heating means of the regenerator, various types such as a gas burner, a heater, and exhaust heat generated from an engine or a fuel cell can be used.

It is a whole schematic block diagram which shows the Example of the absorption refrigerator which concerns on this invention. (A) is a block diagram of a circulation amount control system, and (b) is a block diagram of a liquid film flow rate control system. It is sectional drawing of the principal part of an absorber and an evaporator. FIG. 4 is a view taken along line XX in FIG. 3. It is a graph which shows the correlation with liquid film flow volume (GAMMA) and refrigerant | coolant absorption. (A) is a side view of the absorber which shows the liquid film formation state of an Example, (b) is a side view of the absorber which shows the liquid film formation state of a prior art example. It is a graph which shows the correlation with a load factor and a coefficient of performance (COP).

1 ... Low temperature regenerator
2 ... Condenser
3. Evaporator
4 ... Absorber
9 ... Freezing medium take-out pipe 11 ... High temperature regenerator 20 ... Absorbing liquid spray nozzle (spray mechanism)
29 ... 1st controller (absorption liquid circulation amount adjustment means)
32 ... Heat transfer pipe 35 ... ３８ 38 ... First on-off valve 39 ... Second on-off valve 40 ... Third on-off valve 46 ... Liquid film flow rate table 47 ... Valve selection means

Claims (2)

A regenerator that regenerates the refrigerant by heating the absorbent containing the refrigerant;
A condenser for supplying a refrigerant regenerated and evaporated in the regenerator to condense and liquefy;
An absorber for supplying an absorbent after evaporation of the refrigerant from the regenerator;
An evaporator connected to the absorber and supplying the refrigerant condensed and liquefied by the condenser and evaporating the refrigerant by absorbing the refrigerant by the absorber;
A refrigeration medium take-out pipe for taking out a refrigeration medium attached to the evaporator and cooled by latent heat of vaporization in the evaporator;
An absorbing liquid return pipe connected to the absorber and the regenerator to return the absorbing liquid that has absorbed the refrigerant to the regenerator;
An absorbing liquid circulation amount adjusting means for adjusting the amount of the absorbing liquid after absorbing the refrigerant returned from the absorber to the regenerator in accordance with the taking-out load of the refrigerating medium taken out from the refrigerating medium take-out pipe;
In order to constitute the absorber, a heat transfer tube group that is provided in a multi-row and multi-stage horizontally and passes cooling water inside,
A spraying mechanism that is connected to the absorber and the regenerator and sprays the absorbent after evaporation of the refrigerant from above the heat transfer tube group,
In the absorption refrigerator with
A circulation amount detecting means for detecting a circulation amount of the absorbing liquid;
Multiple cocoons that spray the absorption liquid in a specific heat transfer tube group,
An on-off valve for changing the number of the sprinkles for spraying the absorbing liquid;
Based on the circulation amount of the absorption liquid detected by the circulation amount detection means, a heat transfer tube group for spraying the absorption liquid after evaporation of the refrigerant is selected so that the liquid film flow rate in the heat transfer tube of the absorber is within a predetermined range. A liquid film flow rate control means , and
The liquid film flow rate control means is
Absorbing liquid for adjusting the liquid film flow rate Γ in the range of 0.006 ≦ Γ ≦ 0.02 based on the correlation between the liquid film flow rate Γ (kg / s · m) in the heat transfer tube of the absorber and the amount of refrigerant absorbed. A liquid film flow rate table for pre-correlating and storing the circulation amount of
Based on the circulating amount of the absorbing liquid detected by the circulating amount detecting means, the number of the soot corresponding to the circulating amount is obtained from the liquid film flow rate table, and a valve selection is performed by selecting a predetermined valve from the on-off valve and closing it. Means,
An absorption chiller comprising: In the absorption refrigerator according to claim 1,
Absorption type refrigerator that preferentially selects the heat transfer tube group on the side close to the evaporator .

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