JP3453584B2 - Absorption refrigerator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerator using a low boiling point refrigerant as a cold heat extraction medium.

[0002]

2. Description of the Related Art An absorption refrigeration system provided with an evaporator, an absorber, a regenerator, and a condenser, which gives warm heat to the regenerator and operates by introducing cooling water to the absorber and the condenser to obtain cold heat. There is an opportunity.

A refrigerant (such as water) is contained in the evaporator and the condenser, and a solution for absorbing the refrigerant is contained in the absorber and the regenerator.

Further, as the heat applied to the regenerator, exhaust heat of the engine or fuel cell or the heat of the gas burner is used. There are various ways of using this, for example, a double-effect absorption chiller that uses high-temperature side exhaust heat, a single-effect absorption chiller that uses low-temperature side exhaust heat, and a single-duplex type that uses both high-temperature heat and low-temperature heat. There are heavy-duty combined-use absorption refrigerators.

Of these, the single-effect absorption refrigerator has an evaporator, an absorber, a regenerator, and a condenser, and supplies the regenerator with warm heat (low-temperature heat) obtained from a heat source machine and obtains it through a cooling tower. The operation is carried out by introducing the cooling water to the absorber and the condenser. By this operation, cold heat is obtained from the evaporator, and the cold heat is transported to the indoor unit via the heat transport medium.

Water (cold water) is generally used as the heat transport medium for transporting the cold heat obtained by the evaporator to the indoor unit, but the heat transport power is reduced or water leakage from the heat transport pipe is prevented. In order to achieve this, there are cases where low boiling point refrigerants are adopted.

[0007]

In the case of an absorption refrigerating machine using a low boiling point refrigerant for transporting cold heat, the low boiling point refrigerant is condensed in the heat transfer tube of the evaporator. The condensed liquid low-boiling-point refrigerant may accumulate in the heat transfer tube, which causes the heat transfer tube to be in a liquid-sealed state, resulting in a problem that the ratio of the effective heat transfer area contributing to the condensation heat transfer becomes low. .

A decrease in the ratio of the effective heat transfer area leads to a decrease in the evaporation temperature of the refrigerant (or water) in the evaporator, which causes a reduction in the operating efficiency of the absorption refrigerator.

As a countermeasure, the shape of the evaporator needs to be designed to be relatively large, but this causes a new problem that the size of the absorption refrigerator is increased.

The present invention takes the above circumstances into consideration, and the absorption refrigerator of the first invention determines the ratio of the effective heat transfer area contributing to the condensation heat transfer of the low boiling point refrigerant in the heat transfer tube of the evaporator. It is possible to secure a high value regardless of the condensation amount of the low boiling point refrigerant, which makes it possible to design the shape of the evaporator compactly and to prevent the decrease of the evaporation temperature and avoid the decrease of the operating efficiency. And

The absorption refrigerating machine of the second invention ensures a high ratio of the effective heat transfer area contributing to the condensation heat transfer of the low boiling point refrigerant in the heat transfer tube of the evaporator regardless of the amount of condensation of the low boiling point refrigerant. As a result, it is possible to design the shape of the evaporator in a compact manner, prevent a decrease in the evaporation temperature, avoid a decrease in operating efficiency, and further improve the efficiency of supplying cold heat to the outside. With the goal.

[0012]

An absorption refrigerating machine of a first invention comprises an evaporator, an absorber, a regenerator, and a condenser,
It is operated by supplying heat to the regenerator and introducing cooling water to the absorber and the condenser.The low boiling point refrigerant is introduced into the heat transfer tube of the evaporator, and the low boiling point refrigerant condensed in the heat transfer tube is Bypass from the middle of the heat transfer tube to the outlet.

The absorption refrigerating machine of the second invention comprises an evaporator, an absorber, a regenerator, and a condenser, and heats the regenerator, and introduces cooling water into the absorber and the condenser to operate it. The low boiling point refrigerant is circulated in the heat transfer tube of the evaporator, a bypass flow path is provided from the upstream side to the downstream side of the heat transfer tube in the middle, and the low boiling point refrigerant condensed in the heat transfer tube is The cooling is performed at the final stage of the heat transfer tube.

[0014]

DETAILED DESCRIPTION OF THE INVENTION

(1) A first embodiment of the present invention will be described below with reference to the drawings.

The overall structure of the absorption refrigerator is shown in FIG.

Reference numeral 1 is an evaporator, and a spray head 1 is provided in the container.
a, the heat transfer tube 2, and the liquid refrigerant are contained, and the circulation pipe 3 and the refrigerant pump 4 are additionally provided. When the refrigerant pump 4 is operated, the liquid refrigerant in the container is circulated in the piping 3 for circulation.
Circulate up and down through. The circulating liquid refrigerant exchanges heat with the heat transfer tube 2 and evaporates together with the liquid refrigerant supplied from the condenser 14 described later.

The heat transfer tube 2 is connected to the heat exchanger 24 of the indoor unit 23 via the pipes 21a and 21b. Piping 21a, 2
1b is filled with a low boiling point refrigerant as a heat transport medium, and the low boiling point refrigerant is circulated between the heat transfer tube 2 and the heat exchanger 24 by the operation of the circulation pump 22.

The indoor unit 23 includes an indoor fan 25 in addition to the heat exchanger 24. The indoor fan 25 circulates indoor air, which is a load, through the heat exchanger 24. By this circulation, heat exchange between the indoor air and the low boiling point refrigerant is performed.

The container of the evaporator 1 is in communication with the container of the absorber 5. The absorber 5 contains a solution (LiBr solution or the like) for absorbing a refrigerant and a heat transfer tube 6 in a container. The stored solution absorbs the refrigerant vapor flowing from the evaporator 1, becomes a low concentration, and accumulates in the container.

The heat transfer tube 6 is composed of pipes 41a, 41b, 41c.
Also, it is connected to the cooling tower 43 via the cooling water pump 42, and has a function of releasing the so-called absorption heat generated when the refrigerant is absorbed in the solution to the cooling water supplied from the cooling tower 43.

The cooling tower 43 is equipped with a fan 44, and the heat of the cooling water is released to the outside by the operation of the fan 44.

A pipe 7 is connected to the bottom of the container of the absorber 5, and a solution pump 8 is provided in the pipe 7. The end of the pipe 7 is passed through one of the flow paths of the solution heat exchanger 9 and the regenerator 11
Connected to the top of. That is, by operating the solution pump 8, the solution in the absorber 5 is supplied to the regenerator 11.

The regenerator 11 has a spray head 1 inside the container.
1a, the heat transfer tube 12, and the solution are contained. The heat transfer tube 12 is connected to the heat source device 32 via the pipes 31a and 31b, and the heat supplied from the heat source device 32 and the absorber 5 are connected.
Heat exchange with the solution supplied from. This heat exchange causes the refrigerant in the solution to evaporate.

A pipe 13 is connected to the bottom of the container of the regenerator 11, and the tip of the pipe 13 is connected to the upper part of the container of the absorber 5 via the other flow path of the solution heat exchanger 9.

The container of the regenerator 11 communicates with the container of the condenser 14. The condenser 14 accommodates the liquid refrigerant and the heat transfer tube 15 in a container. The heat transfer tube 15 is connected to the cooling tower 43 through the pipes 41a, 41b, 41c and the cooling water pump 42 together with the heat transfer tube 6 of the absorber 5, and the cooling water supplied from the cooling tower 43 and the regenerator. Heat exchange with the refrigerant vapor flowing from 11 is performed. By this heat exchange, the refrigerant vapor flowing from the regenerator 11 is liquefied, and the liquid refrigerant is accumulated in the container. The accumulated liquid refrigerant flows through the pipe 16 to the spray head 1a of the evaporator 1.

In such a structure, the structure shown in FIG. 1 is adopted for the heat transfer tube 2 of the evaporator 1.

That is, the bypass passage 5 is provided from the midway portion of the heat transfer tube 2 through which the low boiling point refrigerant flows to the outlet portion (final stage).
1 is connected. The bypass flow passage 51 is a tributary flow passage 51a, 51 connected to the midway portions 2a, 2b of the heat transfer tube 2, respectively.
b, and these tributary flow paths are collectively connected in the vicinity of the outlet 2c of the heat transfer tube 2.

The middle portions 2a and 2b of the heat transfer tube 2 are where the conduits are bent, and the liquid low boiling point refrigerant condensed by heat exchange is likely to accumulate.

Next, the operation of the above configuration will be described.

The solution in the absorber 5 absorbs the refrigerant to have a low concentration. This diluted solution is sent to the regenerator 11 via the pipe 7 by the operation of the solution pump 8.

The heat energy of the heat source device 32 is applied to the regenerator 11, and the heat energy causes the refrigerant in the solution in the regenerator 11 to evaporate.

The solution remaining in the regenerator 11 becomes highly concentrated as the refrigerant evaporates. This concentrated solution returns to the absorber 5 through the pipe 13. The concentrated solution passing through the pipe 13 has increased in temperature by receiving heat energy, and the heat of the concentrated solution is transferred to the dilute solution passing through the pipe 7 in the solution heat exchanger 9. By this transfer, thermal energy is effectively used for heating the solution without waste.

The refrigerant vapor generated in the regenerator 11 flows into the condenser 14, where heat is taken by the cooling water flowing in the heat transfer tube 15 and condensed. In this way, the liquid refrigerant accumulates in the condenser 14 and flows through the pipe 16 to the evaporator 1.

The liquid refrigerant flowing into the evaporator 1 is sprayed from the spray head 1a toward the heat transfer tube 2. The sprayed liquid refrigerant takes heat from the low boiling point refrigerant passing through the heat transfer tube 2 and evaporates. The low-boiling-point refrigerant in the heat transfer tube 2 is condensed by being deprived of heat, and the circulation pump 22 is operated to operate the indoor unit 23.
Sent to. In the indoor unit 23, the indoor air is cooled by the low boiling point refrigerant.

The refrigerant vapor generated in the evaporator 1 is absorbed by the absorber 5
Flows into and is absorbed by the solution. After that, the same cycle is repeated.

By the way, the liquid low-boiling-point refrigerant condensed in the heat transfer tube 2 of the evaporator 1 flows into the bypass passage 51 from the midway portions 2a and 2b, passes through the bypass passage 51, and exits from the heat transfer tube 2. It flows to the part 2c.

By virtue of this bypass, the gaseous low boiling point refrigerant will preferentially flow in the heat transfer tube 2, and the ratio of the effective heat transfer area contributing to the condensation heat transfer of the low boiling point refrigerant gas is low boiling point refrigerant. Highly secured regardless of the amount of condensation.

By thus ensuring a high ratio of the effective heat transfer area contributing to the condensation heat transfer, it is not necessary to design the shape of the evaporator 1 to be large, and conversely, it is possible to design compactly. It can greatly contribute to the downsizing of absorption refrigerators.

Further, since the ratio of the effective heat transfer area contributing to the condensation heat transfer is secured to be high, it is possible to prevent the evaporation temperature of the refrigerant in the evaporator 1 from being lowered, and hence the operation efficiency as the absorption refrigerator. Can be prevented from decreasing.

(2) Next, a second embodiment will be described.

As shown in FIG. 3, a bypass flow path 52 is connected from the upstream side to the downstream side of the middle portion of the heat transfer tube 2 into which the low boiling point refrigerant is introduced. The bypass flow passage 52 has tributary flow passages 52a and 52b connected to the midstream upstream regions 2a and 2b of the heat transfer tube 2, respectively, and these tributary flow passages are collectively connected in the midstream downstream region 2c of the heat transfer pipe 2. ing.

In the upstream areas 2a and 2b in the middle of the heat transfer tube 2, the pipe lines are bent and the liquid low boiling point refrigerant condensed by heat exchange is likely to accumulate.

Further, the tributary channels 52a of the bypass channel 52,
A low-boiling-point refrigerant receiver 53 is provided in the midstream downstream region 2c where 52b are collectively connected. The low-boiling-point refrigerant liquid receiver 53 receives the liquid low-boiling-point refrigerant condensed in the heat transfer tube 2 including the bypass portion from the bypass flow passage 52.

The other structure is the same as that of the first embodiment.

The operation will be described.

The liquid low boiling point refrigerant condensed in the heat transfer tube 2 of the evaporator 1 flows into the bypass flow path 52 from the upstream areas 2a and 2b of the intermediate portion, and passes through the bypass flow path 52 to transfer the heat transfer tube 2 to the bypass flow path 52.
It flows to the downstream area 2c in the middle part. Due to this bypass, the gaseous low boiling point refrigerant is preferentially flown in the heat transfer tube 2, and the ratio of the effective heat transfer area that contributes to the condensation heat transfer of the low boiling point refrigerant gas is equal to the condensation amount of the low boiling point refrigerant. Highly secured regardless.

By thus ensuring a high ratio of the effective heat transfer area contributing to the condensation heat transfer, it is not necessary to design the shape of the evaporator 1 to be large, and conversely, it is possible to design compactly. It can greatly contribute to the downsizing of absorption refrigerators.

Further, since the ratio of the effective heat transfer area contributing to the condensation heat transfer is ensured to be high, it is possible to prevent the evaporation temperature of the refrigerant in the evaporator 1 from being lowered, and thus the operation efficiency as the absorption refrigerator. Can be prevented from decreasing.

By the way, the liquid low boiling point refrigerant condensed in the heat transfer tube 2, including the bypass portion from the bypass passage 52, is received by the low boiling point refrigerant receiver 53. By this reception, only the liquid low boiling point refrigerant flows in the final stage region 2d from the midstream downstream region 2c to the outlet 2e of the heat transfer tube 2.

The spray liquid refrigerant from the spray head 1a is sufficiently falling on the final stage region 2d, so that the liquid low boiling point refrigerant flowing through the final stage region 2d is supercooled. The final stage region 2d will function as a low boiling point refrigerant supercooling heat exchanger.

The low boiling point refrigerant which has been sufficiently supercooled in the final stage region 2d flows to the indoor unit 23 via the pipe 21a.
The low-boiling-point refrigerant flowing to the indoor unit 23 is a stable supercooled low-boiling-point refrigerant that does not re-evaporate in the cold heat transporting process, so that the efficiency of supplying cold heat to the external indoor unit 23 is improved, and thus the indoor unit 23 is improved. The cooling operation efficiency of is improved.

(3) A modification of the second embodiment is shown in FIG.

On the wall surface of the evaporator 1, a plurality of communication chambers 61 are arranged in parallel along the vertical direction. Further, on the wall surface of the evaporator 1, a plurality of communication chambers 62 are arranged side by side in the vertical direction on the wall surface on the side facing the communication chambers 61.

The heat transfer tube 2 is divided into a plurality of tubes, and the openings at both ends of each heat transfer tube 2 are connected to each communication chamber 61 and each communication chamber 62. By this connection, the heat transfer tubes 2 are sequentially communicated in a state where they are vertically arranged.

Further, as shown in FIG. 5 (enlarged view of the portion surrounded by the chain double-dashed line in FIG. 4), openings 62b are formed in the partition walls 62a of the communication chambers 62, respectively.
A bypass flow path is formed between the communication chambers 62 through b.

According to such a configuration, the low boiling point refrigerant from the indoor unit 23 flowing through the pipe 21b first flows into the uppermost heat transfer tube 2 through the uppermost communication chamber 61, and the uppermost heat transfer tube 2 The low-boiling-point refrigerant flowing into 2 flows into the heat transfer tube 2 in the second stage from the top via the uppermost communication chamber 62. The low-boiling-point refrigerant that has flowed into the second-stage heat transfer tube 2 is the second communication chamber 61 from the top.
Flow through the heat transfer tube 2 in the third stage from above. Thus
The low boiling point refrigerant is condensed while sequentially flowing through the heat transfer tubes 2, and flows out to the pipe 21a.

The liquid low boiling point refrigerant condensed in each heat transfer tube 2 flows down from the end opening of each heat transfer tube 2 and accumulates on the partition wall 62a of each communication chamber 62 as shown by dots in the figure. The accumulated liquid low-boiling-point refrigerant drips into the lowermost communication chamber 62 through each opening 62b (bypass flow path), and from there, passes through the lowermost heat transfer tube 2 and the lowermost communication chamber 61 to be piped. Two
Flow to 1a.

In this way, the liquid low boiling point refrigerant is supplied to each opening 6
By bypassing through the 2b, the gaseous low boiling point refrigerant mainly flows preferentially in each heat transfer tube 2, and the ratio of the effective heat transfer area contributing to the condensation heat transfer of the low boiling point refrigerant gas is low boiling point. Highly secured regardless of the amount of condensed refrigerant.

By thus ensuring a high ratio of the effective heat transfer area contributing to the condensation heat transfer, it is not necessary to design the shape of the evaporator 1 to be large, and conversely, it is possible to design compactly. It can greatly contribute to the downsizing of absorption refrigerators.

Further, by ensuring a high ratio of the effective heat transfer area contributing to the condensation heat transfer, it is possible to prevent a decrease in the evaporation temperature of the refrigerant in the evaporator 1, and thus the operation efficiency as an absorption refrigerator. Can be prevented from decreasing.

In addition, the liquid low boiling point refrigerant has openings 62b.
It hangs down to the lowest communication chamber 62 through the (bypass flow path), and is housed together there. By this accommodation, only the liquid low boiling point refrigerant flows through the heat transfer tube 2 in the lowermost stage. That is, the lowermost communication chamber 62 has the same function as the low boiling point refrigerant receiver 53 described above.

The spray liquid refrigerant from the spray head 1a is sufficiently falling on the lowermost heat transfer tube 2 as well, so that the liquid low boiling point refrigerant flowing through the lowermost heat transfer tube 2 is subcooled. The lowermost heat transfer tube 2 functions as a low boiling point refrigerant subcooling heat exchanger.

The low boiling point refrigerant that has been sufficiently supercooled in the lowermost heat transfer tube 2 flows into the indoor unit 23 through the lowermost communication chamber 62 and the pipe 21a. The low-boiling-point refrigerant flowing to the indoor unit 23 is a stable supercooled low-boiling-point refrigerant that does not re-evaporate in the cold heat transporting process, so that the efficiency of supplying cold heat to the external indoor unit 23 is improved, and thus the indoor unit 23 is improved. The cooling operation efficiency of is improved.

(4) In each of the above embodiments, the application to the single-effect absorption refrigerating machine was explained, but a double-effect absorption refrigerating machine using high temperature side exhaust heat, both high temperature heat and low temperature heat. The same can be applied to a single-double-effect combined-use absorption refrigerating machine using.

Besides, the present invention is not limited to the above-mentioned embodiments, but various modifications can be made without departing from the scope of the invention.

[0066]

As described above, the absorption refrigerating machine of the first invention is configured to bypass the low boiling point refrigerant condensed in the heat transfer tube of the evaporator from the middle part of the heat transfer tube to the outlet part. Therefore, it is possible to secure a high ratio of the effective heat transfer area that contributes to the condensation heat transfer of the low boiling point refrigerant in the heat transfer tube of the evaporator regardless of the amount of condensation of the low boiling point refrigerant, which makes the shape of the evaporator compact. It is possible to prevent the decrease of the evaporation temperature and avoid the decrease of the operation efficiency.

The absorption refrigerating machine of the second invention is provided with a bypass flow passage from the upstream side to the downstream side of the middle part of the heat transfer tube of the evaporator and transfers the supercooling of the low boiling point refrigerant condensed in the heat transfer tube. Since it is configured at the final stage of the heat pipe, it is possible to secure a high ratio of the effective heat transfer area that contributes to the condensation heat transfer of the low boiling point refrigerant in the heat transfer tube of the evaporator regardless of the condensation amount of the low boiling point refrigerant. As a result, the shape of the evaporator can be designed compactly, the evaporation temperature can be prevented from decreasing, the operation efficiency can be prevented from decreasing, and the efficiency of supplying cold heat to the outside can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a specific configuration of an evaporator according to a first embodiment.

FIG. 2 is a diagram showing an overall configuration of each embodiment.

FIG. 3 is a sectional view showing a specific configuration of an evaporator according to a second embodiment.

FIG. 4 is a sectional view showing the configuration of a modified example of the evaporator in the second embodiment.

FIG. 5 is an enlarged view showing a main part of FIG.

[Explanation of symbols]

1 ... Evaporator 2 ... Heat transfer tube 5 ... Absorber 11 ... Regenerator 14 ... condenser 51 ... Bypass channel 52 ... Bypass channel 53 ... Low boiling point refrigerant receiver 61 ... Communication room 62 ... Communication room 62a ... Partition wall 62b ... opening

─────────────────────────────────────────────────── ─── Continuation of the front page (73) Patent holder 000004226 Nippon Telegraph and Telephone Corporation 2-3-1, Otemachi, Chiyoda-ku, Tokyo (74) Attorney for the above 1 person 100058479 Patent attorney Takehiko Suzue (2 outside) (72) Inventor Tosei Makoto Warabaya, 3-4-1, Shibaura, Minato-ku, Tokyo NTT Corporation (72) Inventor, Tsuneo Uekusa 3-4-1, Shibaura, Minato-ku, Tokyo N・ In the T-facilities (72) Inventor Kazuo Chiba 3-4-1, Shibaura, Minato-ku, Tokyo NTT Corporation (72) Inventor Kenji Machizawa 603 Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Co., Ltd. Tsuchiura Plant (72) Inventor Koji Yamamoto 603 Kandachimachi, Tsuchiura City, Ibaraki Prefecture Hitachi Co., Ltd. Tsuchiura Plant (72) Inventor Kyoji Kono 4-6 Kanda Sugawadai, Chiyoda-ku, Tokyo Within Hitachi Air Conditioning Systems Division (56) References JP-A-9-26223 (JP, A) JP-A-8-327181 (JP, JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F25B 15/00 F25B 39/02

Claims (2)

(57) [Claims] 1. An absorption refrigerating machine comprising an evaporator, an absorber, a regenerator, and a condenser, which heats the regenerator and introduces cooling water into the absorber and the condenser to operate. An absorption chiller, which introduces a low boiling point refrigerant into a heat transfer tube of a heat exchanger and bypasses the low boiling point refrigerant condensed in the heat transfer tube from an intermediate part of the heat transfer tube to an outlet part. 2. An absorption refrigerating machine comprising an evaporator, an absorber, a regenerator, and a condenser, wherein heat is applied to the regenerator and cooling water is introduced into the absorber and the condenser to operate. A low boiling point refrigerant is circulated in the heat transfer tube of the heat exchanger, and a bypass flow path is provided from the upstream side to the downstream side of the middle part of the heat transfer tube. An absorption chiller characterized by being configured in 1.