JPH11311459A - Absorption heat transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively solve the problems of conventional absorption heat transformer, i.e., the coefficient of performance decreases in vain at the time of operation in two stage cycle or more or a pump dedicated for carrying absorption heat generated on the low temperature cycle side to the high temperature cycle is required. SOLUTION: Temperature of heat carrier for taking out hot heat can be set sufficiently high by passing the heat carrier sequentially through a low temperature absorber 2 and a high temperature absorber 3 and when only the low temperature absorber 2 is required to be heated, heat carrier is taken out directly from a low temperature regenerator by switching a three-way valve 52. A high temperature regenerator 4 is heated by branching heat carrier heated through the low temperature absorber 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption heat transformer, for example, a second type absorption heat pump used for recovering waste heat in an industrial process.

[0002]

2. Description of the Related Art A so-called absorption heat transformer is an energy-saving device in which the principle of an absorption refrigeration cycle is applied to obtain a temperature higher than a heat source temperature by using a temperature difference between a low-temperature heat source temperature and cooling water as a driving source. As an industrial process. Regarding such absorption heat transformers, in addition to a single-effect absorption heat transformer composed of one absorber, a two-stage absorption heat transformer in which the absorber is composed of two stages of high temperature and low temperature is also required to have a temperature rising width. It has been proposed as an improved absorption heat transformer.

[0003] As such a two-stage absorption heat transformer, for example, one described in Japanese Patent Application Laid-Open No. 52-76758 is known. The main configuration of this conventional two-stage absorption heat transformer is outlined below. . Each of the high and low temperature absorbers is connected to a separate evaporator with a different pressure level,
The heating medium for taking out hot heat is heated using only the high-temperature side absorber. . As a means for supplying the heat of absorption generated by the low-temperature absorber to the high-temperature absorber in the high-temperature cycle, a heat transfer pipe communicating between the low-temperature absorber and the high-temperature evaporator is provided endlessly, and circulating water Is circulating. . The refrigerant condensed in the condenser is directly sent to the evaporator simply by using a refrigerant pump, and the heat source fluid is supplied to the regenerator and the first evaporator to heat them and then directly discharged to the outside. . A liquid level detector that detects the liquid level in the evaporator, and a control valve that controls the flow rate of the refrigerant flowing into the evaporator according to a signal from the liquid level detector are installed, so that the amount of liquid held at the bottom of the evaporator can be reduced. Controlling. . The transfer of the solution from the absorber to the regenerator uses only the pressure difference between the absorber and the regenerator as the driving force. That is, the solution is transferred from the absorber to the regenerator, for example, after the solution used in the second absorber is used again in the first absorber, and then the solution is sent from the first absorber to the regenerator. , The solution used separately in each of the first and second absorbers is sent from each absorber to the regenerator, or the solution is sent from the high-pressure second absorber to the regenerator, and from this second absorber Sending the solution from the first absorber to the regenerator using a jet pump using the solution sent to the regenerator as the driving fluid,
Furthermore, after the solution of the first absorber is once sent to the high-pressure second absorber using an electric pump, the solution is sent from the second absorber to the regenerator by various methods. All of these use only the pressure difference between the absorber and the regenerator as the driving force.

[0004]

The conventional absorption heat transformer having the above configuration has the following problems.

[0005] Since the heat is extracted only from the high-temperature side absorber, the performance can be improved compared to the single-effect cycle even when the target temperature can be obtained even with a single-effect heat transformer, that is, for example, when the temperature of the cooling water is sufficiently low. The operation is a two-stage cycle with a low coefficient. That is, the coefficient of performance is unnecessarily low under the condition that the temperature of the cooling water is sufficiently low.

[0006] Since the heat of absorption generated by the low-temperature absorber is supplied to the high-temperature side evaporator in the high-temperature cycle by a circulating water loop using an independent heat transfer tube, a dedicated pump or the like is required for circulating the circulating water loop.

[0007] Because the refrigerant condensed in the condenser is simply sent directly to the evaporator using a refrigerant pump,
In heating the refrigerant in the evaporator, not only the amount of heat required for evaporation, but also the amount of heat of the so-called sensible heat for heating the refrigerant to the evaporating temperature is required, which lowers the overall efficiency, that is, the coefficient of performance.

[0008] Since the amount of refrigerant liquid remaining at the bottom of the evaporator is unstable, a liquid level detector is installed in the evaporator, and a control valve is controlled by a signal from the liquid level detector to hold the liquid in the evaporator. Since the liquid volume is controlled, the apparatus and the control system become complicated, and the cost of the entire apparatus increases.

[0009] The transfer of the solution from the absorber to the regenerator
Since only the pressure difference between the absorber and the regenerator is used as the driving force, if a solution heat exchanger is installed between the absorber and the regenerator, a heat exchanger with a large pressure loss cannot be used, and the pressure loss A small and large heat exchanger must be used. However, if the pressure difference between the absorber and the regenerator is sufficiently large, for example, when the solution is sent only from the high-pressure second absorber to the regenerator, the heat exchanger is reduced in size accordingly. be able to. However, this means that a high-pressure second absorber is provided, and that the pressure level of the thermal cycle consists of three stages: a regenerator, a first absorber and a second absorber, i.e. a high-pressure second absorber. It is assumed that it is a two-stage absorption heat transformer that operates two absorbers, a single-effect absorption heat transformer with two pressure levels, and a second-effect absorption heat transformer with the same pressure but only high temperature and concentration. It cannot be applied to a two-stage absorption heat transformer that operates the above absorber.

The present invention has been made in view of the above circumstances, and has as its object to effectively solve various problems in the above-described conventional absorption heat transformer.

[0011]

According to the present invention, there is provided an evaporator for heating and evaporating a liquid refrigerant with an external heat source, and an evaporator for absorbing refrigerant vapor generated by the evaporator into an absorbing solution. Using a low-temperature absorber that obtains a higher temperature than the external heat source by heat, a low-temperature regenerator that heats and concentrates the absorption solution from the low-temperature absorber with the external heat source, and using absorption heat generated by the low-temperature absorber A high-temperature regenerator that heats and concentrates the absorption solution to a higher concentration than in the low-temperature regenerator;
A high-temperature absorber that obtains a higher temperature than in the low-temperature absorber by absorption heat generated by absorbing the refrigerant vapor into the absorption solution from the high-temperature regenerator, and generated by heating and concentrating the absorption solution in each of the regenerators. The refrigerant vapor condensed by heat exchange with the cooling water to form a liquid refrigerant, and a condenser for supplying the liquid refrigerant to the evaporator. There has been proposed an absorption heat transformer characterized by being configured to be able to pass through and heat the high-temperature absorber in order from the vessel.

Further, in the present invention, a branch point is provided in a flow path of the heat medium heated by the low-temperature absorber to the high-temperature absorber, and a part of the heat medium is branched and sent to the high-temperature absorber.
The absorption heat in the low-temperature absorber is configured to be supplied to the high-temperature regenerator, and the heat medium used as a heating source in the high-temperature regenerator is combined with the heat medium entering the low-temperature absorber, or There has been proposed an absorption heat transformer configured to join a heat medium entering a high-temperature absorber at a junction provided downstream of the point.

Further, in the present invention, a three-way valve for switching or branching a heat medium path in the middle of a flow path in which the heat medium heated by the low-temperature absorber is sent to the high-temperature absorber, and switching or branching by the three-way valve. There has been proposed an absorption heat transformer in which a bypass pipe for directly leading the branched heat medium to the outside is provided.

In the present invention, the evaporator heats and evaporates the liquid refrigerant with an external heat source, and the absorption heat generated by absorbing the refrigerant vapor generated in the evaporator into the absorbing solution increases the temperature higher than the external heat source. A low-temperature absorber obtained, a low-temperature regenerator for heating and concentrating the absorbing solution from the low-temperature absorber with the external heat source, and a refrigerant vapor generated by heating and concentrating the absorbing solution in the low-temperature regenerator by heat exchange with cooling water. An absorption heat transformer having at least a condenser for condensing a liquid refrigerant to supply the liquid refrigerant to the evaporator, wherein at least one of the external heat source fluids used for heating one or both of the evaporator and the low-temperature regenerator is provided. A refrigerant preheating heat exchanger for preheating the liquid refrigerant from the condenser by using the section and sending the liquid refrigerant to the evaporator; and a refrigerant conveyance for conveying the liquid refrigerant to the refrigerant preheating heat exchanger. Absorbing heat transformer, characterized in that a and stage have been proposed.

Further, in the present invention, an evaporator for heating and evaporating the liquid refrigerant by an external heat source, and a temperature higher than the external heat source due to absorption heat generated by absorbing the refrigerant vapor generated in the evaporator into the absorbing solution. , A low-temperature regenerator that heats and concentrates the absorbing solution from the low-temperature absorber with the external heat source, and heat exchange between the refrigerant vapor generated by heating and concentrating the absorbing solution in the low-temperature regenerator and cooling water. A condenser that condenses the liquid refrigerant into a liquid refrigerant and supplies the liquid refrigerant to the evaporator, and a refrigerant conveyance unit that conveys the liquid refrigerant from the condenser to the evaporator. A refrigerant jet pump is provided which uses the liquid refrigerant to be sent as a driving fluid and uses the liquid refrigerant retained at the bottom of the evaporator as a suction fluid. Characterized in that the liquid refrigerant so as to supply to the evaporator discharged from the absorption heat transformer it has been proposed.

Further, in the present invention, a high-temperature solution conveying means for conveying the absorbing solution from the bottom of the high-temperature regenerator to the high-temperature absorber, and a part of the absorbing solution discharged from the high-temperature solution conveying means as a driving fluid, From the bottom of the low-temperature regenerator, a solution jet pump is provided that uses an absorption solution sent from the solution jet pump to the high-temperature regenerator as an inhalation fluid, and supplies the absorption solution discharged from the solution jet pump to the high-temperature regenerator. Low-temperature solution conveying means for conveying the absorbing solution to the low-temperature absorber,
A solution jet pump is provided in which a part of the absorbing solution discharged from the low-temperature solution conveying means is used as a driving fluid and the absorbing solution sent from the low-temperature absorber to the low-temperature regenerator is a suction fluid, and the absorbing jet discharged from the solution jet pump is provided. Absorption heat transformers configured to supply a solution to a low temperature regenerator have been proposed.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First
The absorption heat transformer according to the embodiment of FIG.
As shown in the figure, the main structure is composed of an evaporator 1, a low-temperature absorber 2, a high-temperature absorber 3, a high-temperature regenerator 4, a low-temperature regenerator 5, a condenser 6, a high-temperature heat exchanger 7, and a low-temperature heat exchanger 8. ing.

Inside the evaporator 1, an evaporative heat transfer tube 9 for evaporating the refrigerant outside the evaporator 1 is provided, and a refrigerant supply device 10 for supplying the refrigerant from above to the surface of the evaporative heat transfer tube 9 is provided. . On the other hand, a refrigerant jet pump 11 is provided outside the evaporator 1. This refrigerant jet pump 1
1 transports the refrigerant that has not been completely evaporated on the surface of the evaporative heat transfer tube 9 to the refrigerant supply device 10 again by the kinetic energy of the refrigerant transported from the condenser 6. For this purpose, the refrigerant flowing down and staying at the bottom of the evaporator 1 is guided to the refrigerant jet pump 11 through the refrigerant recirculation pipe 12, while
The refrigerant discharged from the refrigerant jet pump 11 is supplied to the refrigerant pipe 1
At 3, it is guided to the refrigerant supply device 10. The arrows shown in the figure indicate the direction in which the liquid in the pipe flows.

The low-temperature absorber 2 is provided in connection with the evaporator 1, and an eliminator 16 for preventing refrigerant droplets from scattering from the evaporator 1 is provided between the two. The low-temperature absorber 2 has an absorption heat transfer tube 14 and a solution supply device 15 installed therein. Then, an absorption solution (hereinafter abbreviated as “solution”) supplied from above to the absorption heat transfer tube 14 by the solution supply device 15 forms a liquid film on the outer surface of the absorption heat transfer tube 14, and this solution is evaporated by the evaporator 1. Absorbs refrigerant vapor. The solution supplied by the solution supply device 15 to the absorption heat transfer tube 14 is a concentrated solution guided from the low-temperature regenerator 5 through the low-temperature heat exchanger 8, and the concentrated solution is guided through a concentrated solution pipe 17. The low-temperature absorber 2 also has a dilute solution pipe 18 extending from the bottom thereof. The dilute solution, which has absorbed the refrigerant vapor and has become thin, is led to the low-temperature heat exchanger 8 through the dilute solution pipe 18.

The high-temperature absorber 3 is connected to the low-temperature absorber 2 and, like the low-temperature absorber 2, has an absorption heat transfer tube 19 and a solution supply device 20 installed therein. Similarly, the solution supply device 20 is placed on the absorption heat transfer tube 19 from above.
Forms a liquid film on the outer surface of the absorption heat transfer tube 14, and this solution absorbs the remaining refrigerant vapor not absorbed by the low-temperature absorber 2 by the refrigerant vapor from the evaporator 1. The concentrated solution that has passed through the high-temperature heat exchanger 7 from the high-temperature regenerator 4 is led to the solution supply device 20 through the concentrated solution pipe 21. The high-temperature absorber 3 has a dilute solution pipe 2
2 is extended, and the dilute solution that has become thinner by absorbing the refrigerant vapor is led to the high-temperature heat exchanger 7 through the dilute solution pipe 22.

The high-temperature regenerator 4 is provided therein with a heat transfer tube 23 for heating and concentrating the dilute solution from the high-temperature absorber 3 again, and a solution supply device 24 for supplying the dilute solution to the surface of the heat transfer tube. . The solution supply device 24 includes a high-temperature absorber 3
The dilute solution having passed through the high-temperature heat exchanger 7 is led through a dilute solution pipe 25. The high temperature regenerator 4 has a
A solution pump 26 that sends a concentrated solution heated and concentrated on the surface of the heat transfer tube 23 is provided. The concentrated solution discharged from the solution pump 26 is guided to the high-temperature heat exchanger 7 through the concentrated solution pipe 27 and further to the high-temperature absorber 3.

The low-temperature regenerator 5 is connected to the high-temperature regenerator 4 and has therein a heat transfer tube 28 for heating and diluting the dilute solution from the low-temperature absorber 2 again, like the high-temperature regenerator 4. A solution supply device 29 for supplying a dilute solution to the surface of the heat transfer tube is provided. The solution supply device 29 includes a low-temperature absorber 2
The dilute solution having passed through the low-temperature heat exchanger 8 is led through a dilute solution pipe 30. Further, the low-temperature regenerator 5 is
Similarly, a solution pump 31 for sending a concentrated solution heated and concentrated on the surface of the heat transfer tube 28 is provided below the concentrated solution pipe 31, and the concentrated solution discharged from the solution pump 31 is subjected to low-temperature heat exchange through a concentrated solution pipe 32. To the low-temperature absorber 2.

The condenser 6 is connected to the low-temperature regenerator 5, and an eliminator 34 for preventing the solution droplets from scattering from the low-temperature regenerator 5 to the condenser 6 is provided between the condenser 6 and the low-temperature regenerator 5. Have been. The condenser 6 is provided therein with a condensation heat transfer tube 33 for condensing refrigerant vapor generated when the solution is heated and concentrated by the high temperature regenerator 4 and the low temperature regenerator 5 outside the tube. The condenser 6 has a condensing heat transfer tube 3
A refrigerant pump 35 for sending the refrigerant that has condensed and flowed down on the surface of No. 3 is provided. The liquid refrigerant discharged from the refrigerant pump 35 is guided to the refrigerant pipe 36, passes through the heat exchanger 37 for preheating the refrigerant, and then is guided to the refrigerant jet pump 11, where the evaporator 1 serves as a driving fluid for the refrigerant jet pump 11.
After being sucked and mixed with the liquid refrigerant from the bottom of the evaporator, the liquid refrigerant is led to the evaporator 1 through the refrigerant pipe 13.

Here, the refrigerant preheating heat exchanger 37 preheats the refrigerant using the drain after the external heat source fluid has been used for heating in the evaporator 1 and the low-temperature regenerator 5, respectively. , Also functions as a drain cooler. The heat exchanger 37 for preheating the refrigerant includes an evaporator 1
Heat source fluid pipe 38 for guiding the heat source fluid flowing in the evaporative heat transfer tube 9, heat source fluid pipe 39 for guiding the heat source fluid flowing in the heat transfer tube 28 of the low temperature regenerator 5, and the heat source fluid passing through the heating side flow path. Are connected to a heat source fluid pipe 40 that guides the refrigerant to the outside, a refrigerant pipe 36 is connected to an inlet of the heated side flow path, and a refrigerant jet pump 11 is connected to the outlet side of the heated side flow path via the refrigerant pipe 36. Is connected.

In this embodiment, hot water is used as a heat medium for extracting heat energy having a higher temperature than the heat source temperature to the outside. Further, in the present embodiment, the entire amount of the hot water is first guided to the low-temperature absorber 2 by the hot water circulation pump 51 as a transport means. That is, the hot water supplied from the outside and discharged from the hot water circulation pump 51 is:
The whole amount is guided to the three-way valve 52 after passing through the low-temperature absorber 2. This three-way valve has two outlets. A bypass hot water pipe 53 for guiding hot water directly to the hot water outlet extends to one outlet, and a pipe connected to the other outlet branches into hot water pipes 54 and 55. Hot water piping 54
Guides a portion of the hot water to the high temperature regenerator 4 at a flow rate adjusted by the flow rate adjusting throttle 56. After passing through the high-temperature regenerator 4, the hot water is guided to the suction side of the hot-water circulation pump 51 via the hot-water pipe 57, where it joins with the hot water from the load system. On the other hand, the hot water pipe 55 is connected to the high temperature absorber 3. Then, the high-temperature absorber 3 is guided by the hot water pipe 55.
Is passed through the hot water outlet.

The operation of the absorption heat transformer according to the present embodiment as described above will be described below. In the present embodiment, low-pressure steam is used as the heat source fluid, and heat energy is supplied by condensing the steam inside the evaporator heat transfer tube 9 in the evaporator 1 and the heat transfer tube 28 in the low-temperature regenerator 5. doing. Hereinafter, this steam is referred to as heat source steam and is distinguished from refrigerant steam.

In the condenser 6, the refrigerant vapor generated when the solution is heated and concentrated in the high temperature regenerator 4 and the low temperature regenerator 5 is cooled by the cooling water flowing inside the condensing heat transfer tube 33 and condensed outside the tube. I do. The condensed refrigerant is supplied to the refrigerant pump 35
And is conveyed to the heated side flow path of the refrigerant preheating heat exchanger 37, where it exchanges heat with the drain generated in each of the evaporator 1 and the low-temperature regenerator 5 and is preliminarily heated. The refrigerant heated by the refrigerant preheating heat exchanger 37 sucks and mixes the liquid refrigerant from the bottom of the evaporator 1 in the refrigerant jet pump 11, and is then guided to the evaporator 1 via the refrigerant pipe 13.

The refrigerant flowing into the evaporator 1 is supplied to the surface of the evaporative heat transfer tube 9 by the refrigerant supply device 10, and is heated and evaporated by the condensation of the heat source vapor generated inside the heat transfer tube.
The refrigerant vapor generated by evaporating the refrigerant in this manner is absorbed by each of the low-temperature absorber 2 and the high-temperature absorber 3. On the other hand, the drain generated by the condensation of the heat source vapor inside the heat transfer tube is discharged by the heat source fluid pipe 38 to the refrigerant preheating heat exchanger 3.
7 is led to the heating side flow path.

In the low-temperature absorber 2, the concentrated solution heated and concentrated in the low-temperature regenerator 5 exchanges heat with the dilute solution in the low-temperature heat exchanger 8 and further heated. Supplied to This concentrated solution is supplied to the absorption heat transfer tube 1
A falling liquid film is formed on the surface of the evaporator 4 to absorb the refrigerant vapor from the evaporator 1. Hot water as a heat medium flows in the absorption heat transfer tube 14, and the hot water is heated by absorption heat generated by absorption of the refrigerant vapor. The diluted solution that has absorbed the refrigerant vapor exchanges heat with the concentrated solution from the low-temperature regenerator 5 in the low-temperature heat exchanger 8 to lower the temperature, and is then guided to the low-temperature regenerator 5 again. At this time, when the temperature of the hot water at the outlet of the low-temperature absorber 2 has reached the target temperature, the entire amount of the hot water is guided to the bypass hot water pipe 53 by the three-way valve 52 to be directly taken out and used.

On the other hand, when the temperature of the hot water at the outlet of the low-temperature absorber has not reached the target temperature, the three-way valve 52 guides the hot water to the high-temperature absorber 3 and the high-temperature regenerator 4. In the high-temperature absorber 3, the high-temperature regenerator 4 heats and concentrates to a higher concentration than in the low-temperature regenerator 5 as described later, and exchanges heat with the dilute solution from the high-temperature absorber in the high-temperature heat exchanger 7. Further, the heated concentrated solution is supplied from the solution supply device 20 to the surface of the absorption heat transfer tube 19. This concentrated solution also forms a falling liquid film on the surface of the absorption heat transfer tube in the same manner as the low temperature absorber to absorb the refrigerant vapor from the evaporator 1, and at this time, generates a higher absorption heat than the low temperature regenerator 5. I do. Then, the hot water flowing in the absorption heat transfer tube 19 is further heated by the absorption heat, and the heated hot water is guided to the outside and used.
On the other hand, the diluted solution that has become thinner by absorbing the refrigerant vapor exchanges heat with the concentrated solution from the high-temperature regenerator 4 in the high-temperature heat exchanger 7 to lower the temperature, and is then guided to the high-temperature regenerator 4 again.

The high-temperature regenerator 4 regenerates the dilute solution guided from the high-temperature absorber 3 through the high-temperature heat exchanger 7 as described above. Therefore, the dilute solution from the high temperature absorber 3
A falling liquid film is formed on the surface of the heat transfer tube 23, and is heated and concentrated by hot water supplied from the low-temperature absorber 2 and flowing through the heat transfer tube 23 to become a concentrated solution. The concentrated solution is pressurized by a solution pump 26 serving as a solution conveying means, and is sent from the concentrated solution pipe 27 to the high-temperature absorber 3 via the high-temperature heat exchanger 7 again. On the other hand, the refrigerant vapor generated by concentration of the solution reaches the condenser 6 through the low-temperature regenerator 5 connected to the high-temperature regenerator 4 and condenses there. The hot water whose temperature has been lowered by heating and concentrating the solution is led to the suction side of the hot water circulation pump 51 through the hot water pipe 57, merges with the hot water refluxed from the load system, and is supplied to the low-temperature absorber 2 again. You.

The above operations in the high-temperature absorber 3 and the high-temperature regenerator 4 are not performed when the temperature of the hot water at the outlet of the low-temperature absorber 2 has reached a target temperature. That is, in this case, as described above, the entire amount of hot water is supplied to the three-way valve 52.
Is led to the bypass hot water pipe 53 by the high-temperature absorber 3
No hot water flows in the absorption heat transfer tube 19, no supply of the concentrated solution from the high temperature regenerator 4, and no absorption of refrigerant vapor.
In the high-temperature regenerator 4, hot water does not flow through the heat transfer tube 23, there is no flow of the dilute solution from the high-temperature absorber 3, and neither heat exchange nor heat concentration of the dilute solution occurs.

The low-temperature regenerator 5 regenerates the solution guided from the low-temperature absorber 2 through the low-temperature heat exchanger 8 as described above. Therefore, the solution from the low-temperature absorber 2 forms a falling liquid film on the surface of the heat transfer tube 28 as in the high-temperature regenerator 4. Then, the heat source vapor flowing there is condensed inside the heat transfer tube 28, and the solution is heated and concentrated by the heat of condensation generated at that time to become a concentrated solution. This concentrated solution is pressurized by a solution pump 31 which is a solution conveying means, and is sent from the concentrated solution pipe 32 to the low temperature absorber 2 via the low temperature heat exchanger 8 again. On the other hand, the refrigerant vapor generated by the concentration of the solution reaches the condenser 6 connected to the low-temperature regenerator 5 and condenses. Drain generated by condensation of the heat source vapor is supplied to the heat source fluid pipe 39.
After being joined to the drain generated in the evaporator 1 as described above, it is guided to the heating-side flow path of the refrigerant preheating heat exchanger 37.

FIG. 2 shows the relationship between the temperature and the pressure of each element in the cycle of the absorption heat transformer described above. The evaporator 1 and the low-temperature regenerator 5 that are heated by the heat source vapor as the heat source fluid from the outside are heated to tE and tLGo, respectively, slightly lower than the heat source temperature. When the solution heated and concentrated in the low-temperature regenerator 5 absorbs the refrigerant vapor in the low-temperature absorber 2 and heats the hot water with the heat of absorption, the hot water is heated to a temperature slightly lower than tLAo. As is clear from FIG. 2, the temperature is higher than the heat source temperature. Therefore, the solution of the high-temperature regenerator heated and concentrated by the hot water is also concentrated at a higher temperature than the solution of the low-temperature regenerator heated by the heat source steam.

At this time, since the low-temperature regenerator 5 and the high-temperature regenerator 4 operate at the same pressure level PC as shown in FIG.
Higher temperature regenerators, which are concentrated at higher temperatures, provide higher concentrations. Therefore, the solution concentration of the high-temperature absorber 3 also
Solution concentration. These are the same pressure level P
2, the absorption temperature tHAo of the high-temperature absorber 3 becomes higher than the absorption temperature tLAo of the low-temperature absorber 2 as shown in FIG. 2, and therefore, the high-temperature absorber 3 removes the hot water heated by the low-temperature absorber. It can be further heated.

The heating of the hot water by the low-temperature absorber 2 in the absorption heat transformer of the first embodiment is regarded as heating of the hot water by the single-effect cycle because the concentrated solution heated and concentrated by the heat source fluid is directly used. The heating of the hot water by the high-temperature absorber 3 can be regarded as the heating of the hot water by the two-stage cycle since the concentrated solution heated and concentrated by the hot water having a higher temperature than the heat source fluid obtained in the single-effect cycle is used. be able to.

Next, the relationship between the external condition and the hot water outlet temperature in the absorption heat transformer of the first embodiment will be described with reference to FIG. 3 taking the cooling water temperature as an example of the external condition. In FIG. 3, the horizontal axis represents the inlet temperature of the cooling water, which is an example of the external condition, and the vertical axis represents the outlet temperature of the hot water. The curve shown by a broken line in the figure is a characteristic in the case of a single-effect cycle, and corresponds to the hot water outlet temperature of the low-temperature absorber 2 in the present embodiment. Further, the curve represented by the solid line shows the characteristics in the case of the two-stage cycle, and corresponds to the hot water outlet temperature of the high temperature absorber 3 in the present embodiment. Note that FIG.
The characteristics shown in are not ideal characteristics,
It is a realistic calculation result in consideration of a solution concentration difference between an absorber and a regenerator, an approach temperature of each heat exchanger, and the like. As a calculation condition, the condensation temperature of the heat source vapor is set to 60 ° C.

As shown in FIG. 3, at the outlet temperature of the hot water, a higher temperature is obtained in the two-stage cycle than in the single-effect cycle. On the other hand, when comparing theoretical coefficients of performance,
The single-effect cycle is 0.5, whereas the two-stage cycle is as low as about 0.33. Therefore, if the desired hot water removal temperature can be obtained in a single-effect cycle,
Although it is more advantageous to use a single-effect cycle, one of the features of the absorption heat transformer according to the present invention is that this advantage can be effectively used. That is, when the target hot water removal temperature is obtained even with a single-effect cycle, that is, when it is obtained only with the low-temperature absorber 2, as described above, heating is performed by the low-temperature absorber 2 without passing through the high-temperature absorber 3. The hot water can be led directly to the hot water outlet by switching the three-way valve 52.

Even when the desired hot water discharge temperature cannot be obtained by a single-effect cycle, it is advantageous to cover the heating of the hot water with a single-effect cycle having a large coefficient of performance as much as possible. This advantage can also be effectively utilized in the absorption heat transformer according to the present invention. That is, in the present invention, the entire amount of hot water supplied from the load system is first heated in the single-effect cycle having a high coefficient of performance, that is, the low-temperature absorber 2, and then the two-stage cycle having a low coefficient of performance, that is, in the high-temperature absorber 3, Because of the heating configuration, even if the target hot water discharge temperature cannot be obtained in the single-effect cycle, a high coefficient of performance in the single-effect cycle can be contributed. It can be. Specifically, assuming that the heating amounts of the low-temperature absorber 2 and the high-temperature absorber 3 are 1: 1, the theoretical coefficient of performance is the central value of the single-effect cycle and the two-stage cycle, that is, about 0.42. Of the two-stage cycle of
Values higher than 33 are obtained.

Here, the setting method of the three-way valve 52 will be described.
An example will be described in which the target hot water extraction temperature is 75 ° C. and the absorption heat transformer has the characteristics shown in FIG. When the cooling water temperature is about 21.5 ° C. or less, a single-effect cycle is obtained from FIG. 3, that is, a hot water temperature of 75 ° C. is obtained by the low-temperature absorber 2, so that the hot water passing through the low-temperature absorber 2 is It is led directly to the hot water outlet through the hot water pipe 53. When the temperature of the cooling water rises, the single-effect cycle in FIG. 3, that is, the outlet temperature of the hot water from the low-temperature absorber 2 does not reach 75 ° C., and the three-way valve 52 guides the hot water to the high-temperature absorber 3 for further heating. At this time, a part of the hot water heated by the low-temperature absorber 2 is guided to the high-temperature regenerator 4 linked to the high-temperature absorber 3 to heat and concentrate the solution there. This concentrated solution is sent to the high-temperature absorber 3 Working on heating is as described above.

The main effects that the absorption heat transformer in the first embodiment described above can bring are as follows. Since the hot water is heated first by the low-temperature absorber 2 and then heated by the high-temperature absorber 3 as necessary, the heating of the hot water is performed by a single-effect cycle having a high theoretical coefficient of performance and a two-stage type having a large temperature rise width. It is performed in two stages of the cycle and has a higher coefficient of theoretical performance than a normal two-stage cycle.

When the hot water is heated in two stages, the low-temperature absorber 2 and the high-temperature absorber 3, a part of the water is branched from the low-temperature absorber 2 through the three-way valve 52 to the high-temperature absorber 3. Then, one of them is used as a heating source of the high-temperature regenerator, that is, the entire amount of hot water from the load system is always heated by the low-temperature absorber 2, so that the absorption heat transfer tube 14 in the low-temperature absorber is Also, the whole works effectively during the two-stage operation, and the performance during the two-stage operation is improved.

Since the hot water branched for heating in the high-temperature regenerator 4 is joined again to the hot water inlet of the low-temperature absorber, it is not necessary to affect the water temperature at the inlet of the high-temperature absorber or at the outlet of the hot water. .

When returning the hot water used in the high-temperature regenerator 4 to the low-temperature absorber 2, the hot water is joined to the suction side of the hot-water circulating pump 51.
The transfer of the absorbed heat generated in
There is no need to separately provide a transport means such as a pump, and the apparatus structure can be simplified accordingly.

A restrictor 56, which is a resistance element for adjusting the flow rate of hot water in this flow path, is provided at the inlet of the high-temperature regenerator in the flow path from the branch point of the hot water to the junction on the suction side of the hot water circulation pump. So, the hot water flow rate that branches to the high temperature regenerator,
Since the flow rate can be adjusted to the minimum necessary for heating the high-temperature regenerator, the hot water circulation pump 5
The capacity of 1 also requires the minimum necessary discharge amount.

A bypass hot water pipe 53 branching from a hot water flow path from the low temperature absorber 2 to the high temperature absorber 3 is provided. The bypass hot water pipe 53 bypasses the high temperature absorber 3 and directs hot water to the hot water outlet. At the same time, since the three-way valve 52 is installed at the branch point of the bypass hot water pipe 53, the three-way valve 52 is used to guide the hot water to the high-temperature absorber 3 and the high-temperature regenerator 4, respectively. The operation can be selectively switched between single-effect operation and direct operation to the hot water outlet directly via the bypass hot water pipe 53. Therefore, optimal operation can be performed according to external conditions such as the temperature of the cooling water and the required temperature of removing hot water. In other words, when the cooling water temperature is low and the desired hot water temperature can be obtained in the single-effect cycle, the single-effect operation having a high coefficient of performance is performed, and when the cooling water temperature is high and the desired hot-water temperature cannot be obtained in the single-effect cycle, the temperature rises. Operation in a two-stage cycle with a large temperature range can be performed.

The heat source fluid used for heating the evaporator 1 and the low-temperature regenerator 5, that is, the heat exchanger 37 for preheating the refrigerant, which uses the drain generated by condensation of the heat source vapor as the heat source, is evaporated from the condenser 6. Since the refrigerant sent to the evaporator is provided in the refrigerant flow path to the evaporator 1 and is preliminarily heated by the refrigerant preheating heat exchanger 37, the amount of heating by the heat source vapor can be reduced with respect to the sensible heat.

Since the refrigerant pump 35, which is a means for conveying the refrigerant from the condenser 6 to the evaporator 1, is provided on the inlet side of the refrigerant preheating heat exchanger 37, the temperature of the refrigerant conveyed by the refrigerant pump 35 is controlled by the refrigerant preheating. The temperature can be around the condensing temperature before being overheated by the heat exchanger 37 for use, so that trouble due to overheating of the pump does not occur, or a means for preventing overheating of the pump can be dispensed with.

The refrigerant discharged from the refrigerant jet pump 11 is supplied to the refrigerant supply device 10 using the refrigerant discharged from the refrigerant pump 35 as the driving fluid and the refrigerant staying at the bottom of the evaporator 1 as the suction fluid. Because there is, evaporator 1
The fluctuation of the amount of refrigerant in the above can be reduced. That is, when the amount of the refrigerant retained in the evaporator is large, the liquid level of the refrigerant stagnating at the bottom rises and the suction flow rate of the refrigerant jet pump 11 increases. Since the flow rate also increases, evaporation is promoted and the amount of refrigerant retained in the evaporator decreases. Conversely, when the amount of the retained refrigerant is small, the liquid level in the evaporator decreases, and the suction flow rate of the refrigerant jet pump 11 decreases. Therefore, the flow rate of the refrigerant supplied to the surface of the evaporative heat transfer tube 9 also decreases to evaporate. Since the amount also decreases, the refrigerant that has not completely evaporated stays at the bottom of the evaporator 1, and the amount of refrigerant retained increases. Therefore, the amount of the retained refrigerant is automatically adjusted, and the fluctuation in the amount of the retained refrigerant in the evaporator is reduced.

A second embodiment of the present invention will be described with reference to FIG. The configuration of the present embodiment is the same as that of the first embodiment except for the following points.
One of the differences is that, as is apparent from the figure, the hot water branched for heating the high-temperature regenerator heats the solution in the high-temperature regenerator 4 to reduce the temperature, and then absorbs the high-temperature from the branch point. That is, it joins the hot water pipe 55 leading to the vessel 3. Along with this, a resistance element 56a for adjusting the distribution amount of the hot water at the branch position is connected to the low-temperature absorber 2
It is provided in the flow path of warm water that enters directly into the water. Another difference is that the dilute solution pipe 25 extending from the heating-side flow path of the high-temperature heat exchanger 7 to the solution supply device 24 of the high-temperature regenerator 4 has a U-shaped portion 25u.
Is provided.

In the second embodiment having such a configuration, the hot water from the high-temperature regenerator 4 is joined to the hot water inlet of the high-temperature absorber 3, so that the high-temperature absorber is compared with the first embodiment. Although the temperature of the hot water inlet 3 decreases and the required amount of heating in the high-temperature absorber increases, the amount of hot water borne by the hot-water circulation pump 51 is reduced by the amount of the hot-water circulation of the high-temperature regenerator 3. The pump 51 can be reduced in size and power consumption can be reduced.

According to the second embodiment, the flow rate of the hot water sent to the load system in the first embodiment is smaller in the two-stage operation than in the single-effect operation. Even in the mold operation, the flow rate of the hot water sent to the load system becomes almost equal.

Further, according to the second embodiment, since the U-shaped portion 25u is provided in the dilute solution pipe 25, the solution pump 26 is stopped during the single-effect operation and the solution cannot be sent to the high-temperature absorber 3. In this case, the solution can be left in the U-shaped portion 25u, and the high pressure section including the high temperature absorber 3 and the low pressure section including the high temperature regenerator 4 are separated by the remaining solution. Performance degradation can be prevented.

In the absorption heat transformer according to the third embodiment of the present invention, as shown in FIG.
In addition to providing a U-shaped portion 25u in the dilute solution pipe 25, a U-shaped portion 30u is further provided in a dilute solution pipe 30 that extends from the low-temperature absorber to the low-temperature regenerator 5 after passing through the low-temperature heat exchanger 8. Other configurations in the third embodiment are basically the same as those in the first embodiment.

In the present embodiment, similarly to the second embodiment, not only can the performance drop due to steam blow-through during single-effect operation be prevented, but also the entire apparatus can be temporarily shut down, such as during an emergency stop or power outage. It is also possible to speed up the performance recovery when restarting after stopping. That is, when the entire device stops, not only the high-temperature cycle but also the low-temperature cycle naturally stop, and there is a possibility that refrigerant vapor blows through both of them, and these factors delay the performance recovery at restart. However, this can be prevented by the solution remaining in each of the U-shaped portion 25u and the U-shaped portion 30u.

In the absorption heat transformer according to the fourth embodiment of the present invention, as shown in FIG.
A solution jet pump 41 driven by a part of the concentrated solution discharged from the solution pump 26 is provided in the dilute solution flow path from the outlet of the heating side flow path of the high temperature heat exchanger 7 to the high temperature regenerator 4.
And a solution jet pump driven by a part of the concentrated solution discharged from the solution pump 31 in the dilute solution flow path from the outlet of the heating side flow path of the low temperature heat exchanger 8 to the low temperature regenerator 5. 42 are installed. In this manner, the solution jet pumps 41 and 42 suck the dilute solution from the high-temperature absorber or the low-temperature absorber through the low-temperature heat exchanger 7 or the low-temperature heat exchanger 8, thereby causing the low-temperature heat exchanger 7 or The allowable value of the pressure loss of the low-temperature heat exchanger 8 increases, and the heat exchanger can be downsized.

As shown in FIG. 6, these solution jet pumps 41 and 42 are respectively connected to the solution supply device 2.
By installing the U-shaped portion 25u or the U-shaped portion 30u in the third embodiment, by placing the U-shaped portion 25u or the solution supply device 29 at a lower position.

In the above description, it is assumed that the three-way valve 52 is used to alternately switch between single-effect operation and two-stage operation, and that the low-temperature absorber is also used. It is also possible to divert the passed hot water appropriately in accordance with the outlet temperature of the hot water, pass a part of the hot water through the bypass hot water pipe 53, and reheat the rest with the high-temperature absorber, and in this case, a three-way valve By continuously controlling 52, the branching ratio can be changed continuously. By doing so, the behavior of the hot water outlet temperature with respect to the fluctuation of the cooling water temperature is further stabilized.

In each of the above-described embodiments, an example in which a two-stage operation can be performed is provided. However, if a higher-temperature cycle is added as necessary, a three-stage operation or a further operation can be performed. Of course, it is also possible to make it possible to carry out the operation as required.

[0060]

As described above, according to the present invention, various problems in the conventional absorption heat transformer can be effectively solved, and an absorption heat transformer having better performance can be realized.

[Brief description of the drawings]

FIG. 1 is a system diagram of an absorption heat transformer according to a first embodiment.

FIG. 2 is a graph showing a mutual relationship between temperature and pressure in the absorption heat transformer of FIG. 1 on a During diagram.

FIG. 3 is a graph comparing the relationship between the cooling water temperature and the hot water outlet temperature in the absorption heat transformer of FIG. 1 between a single-effect cycle and a two-stage cycle.

FIG. 4 is a main part system diagram of an absorption heat transformer according to a second embodiment.

FIG. 5 is a main part system diagram of an absorption heat transformer according to a third embodiment.

FIG. 6 is a main part system diagram of an absorption heat transformer according to a fourth embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 evaporator 2 low-temperature absorber 3 high-temperature absorber 4 high-temperature regenerator 5 low-temperature regenerator 6 condenser 7 high-temperature heat exchanger 8 low-temperature heat exchanger 9 evaporative heat transfer tube 10 refrigerant supply device 11 refrigerant jet pump 12 refrigerant recirculation pipe 13 Refrigerant piping 14,19 Absorption heat transfer tube 15,20,24,29 Solution supply device 17,21,27,32 Concentrated solution piping 18,22,25,30 Dilute solution piping 25u, 30u U-shaped part 23,28 Heat transfer tube 26 , 31 Solution pump 33 Condensing heat transfer tube 35 Refrigerant pump 36 Refrigerant pipe 37 Refrigerant preheating heat exchanger 38, 39, 40 Heat source fluid pipe 41, 42 Solution jet pump 51 Hot water circulation pump 52 Three-way valve 53 Bypass hot water pipe 54, 55, 57 Hot water piping 56, 56a Restrictor

Claims (17)

[Claims] 1. An evaporator for heating and evaporating a liquid refrigerant with an external heat source, and a low-temperature absorber for obtaining a higher temperature than the external heat source by absorbing heat generated by absorbing refrigerant vapor generated in the evaporator into an absorbing solution. Vessel, a low-temperature regenerator that heats and concentrates the absorbing solution from the low-temperature absorber with the external heat source, and makes the absorbing solution have a higher concentration than in the low-temperature regenerator using the heat of absorption generated by the low-temperature absorber. A high-temperature regenerator that heats and concentrates, a high-temperature absorber that obtains a higher temperature than in the low-temperature absorber by absorption heat generated by absorbing the refrigerant vapor into the absorbing solution from the high-temperature regenerator, and each of the regenerators A heat exchanger comprising at least a condenser for condensing refrigerant vapor generated by heating and concentrating the absorption solution with cooling water into a liquid refrigerant and supplying the liquid refrigerant to the evaporator. An absorption heat transformer, wherein the former is configured to be able to heat by passing a heat medium for taking out heat to the outside from the low-temperature absorber to the high-temperature absorber in this order. 2. A low-temperature absorber, wherein a branch point is provided in a flow path of a heat medium heated by a low-temperature absorber to a high-temperature absorber, and a part of the heat medium is branched and sent to the high-temperature absorber. The absorption heat transformer according to claim 1, wherein the heat absorption in (1) is supplied to a high-temperature regenerator. 3. The absorption heat transformer according to claim 2, wherein the heat medium used as a heating source in the high temperature regenerator is combined with the heat medium entering the low temperature absorber. 4. A heat medium circulating pump is provided at a heat medium inlet of a low temperature absorber, and a heat medium from the high temperature regenerator is joined to a suction side of the heat medium circulating pump. An absorption heat transformer according to claim 3, characterized in that: 5. The absorption heat transformer according to claim 2, wherein a resistance element for adjusting a flow rate of the heat medium sent to the high-temperature regenerator is provided downstream of the branch point. 6. The heat medium used as a heating source in the high-temperature regenerator is configured to be combined with a heat medium entering the high-temperature absorber at a junction provided downstream of the branch point. The absorption heat transformer according to claim 2, wherein 7. The absorption device according to claim 6, wherein a resistance element for adjusting a distribution amount at the branch point is provided between the branch point of the heat medium and the junction point downstream of the branch point. Heat transformer. 8. A three-way valve for switching or branching a heat medium path in the middle of a flow path in which the heat medium heated by the low-temperature absorber is sent to the high-temperature absorber, and switched or branched by the three-way valve. The absorption heat transformer according to any one of claims 1 to 7, further comprising a bypass pipe for directly leading a heat medium to the outside. 9. An evaporator that heats and evaporates a liquid refrigerant with an external heat source, and a low-temperature absorber that obtains a higher temperature than the external heat source by absorbing heat generated by absorbing refrigerant vapor generated in the evaporator into an absorbing solution. A low-temperature regenerator for heating and concentrating the absorbing solution from the low-temperature absorber with the external heat source, and condensing refrigerant vapor generated by heating and concentrating the absorbing solution in the low-temperature regenerator by heat exchange with cooling water. An absorption heat transformer having at least a condenser serving as a liquid refrigerant and supplying the liquid refrigerant to the evaporator, wherein at least a part of the external heat source fluid used for heating one or both of the evaporator and the low-temperature regenerator is used. A heat exchanger for preheating the refrigerant, which preheats the liquid refrigerant from the condenser and sends the liquid refrigerant to the evaporator, and refrigerant conveying means for conveying the liquid refrigerant to the heat exchanger for preheating the refrigerant. Absorption heat transformer, wherein the door. 10. The external heat source fluid is steam, and heat of condensation is used to heat the evaporator and the low-temperature regenerator, and at least a part of the drain generated by the heating is supplied to the heat source in the heat exchanger for preheating the refrigerant. The absorption heat transformer according to claim 9, wherein: 11. An evaporator that heats and evaporates a liquid refrigerant with an external heat source, and a low-temperature absorber that obtains a higher temperature than the external heat source by absorbing heat generated by absorbing refrigerant vapor generated by the evaporator into an absorbing solution. A low-temperature regenerator for heating and concentrating the absorbing solution from the low-temperature absorber with the external heat source, and condensing refrigerant vapor generated by heating and concentrating the absorbing solution in the low-temperature regenerator by heat exchange with cooling water. An absorption heat transformer comprising at least a condenser for supplying a liquid refrigerant to the evaporator and supplying the liquid refrigerant from the condenser to the evaporator, wherein the liquid refrigerant sent by the refrigerant conveyance means Is provided as a driving fluid, a refrigerant jet pump is provided which uses a liquid refrigerant retained at the bottom of the evaporator as a suction fluid, and is discharged from the refrigerant jet pump. Absorbing heat transformer, characterized in that the liquid refrigerant so as to supply to the evaporator. 12. In the solution flow path from the high-temperature absorber to the high-temperature regenerator, or in both the solution flow path from the high-temperature absorber to the high-temperature regenerator and the solution flow path from the low-temperature absorber to the low-temperature regenerator. The absorption heat transformer according to any one of claims 1 to 8, wherein a U-shaped tube is provided. 13. A U-shaped tube is provided in a solution flow path from a low-temperature absorber to a low-temperature regenerator.
An absorption heat transformer according to one of the preceding claims. 14. A high-temperature solution conveying means for conveying an absorbing solution from the bottom of a high-temperature regenerator to a high-temperature absorber, and high-temperature regenerating from the high-temperature absorber using a part of the absorbing solution discharged from the high-temperature solution conveying means as a driving fluid. 9. A method according to claim 1, further comprising the step of: providing a solution jet pump using an absorption solution sent to the vessel as a suction fluid, and supplying the absorption solution discharged from the solution jet pump to a high-temperature regenerator. An absorption heat transformer according to one of the above. 15. The absorption heat transformer according to claim 14, wherein the solution jet pump is provided such that a suction port thereof is located at a position lower than a solution discharge level of a solution supply device in a high-temperature regenerator. . 16. A low-temperature solution conveying means for conveying an absorbing solution from the bottom of a low-temperature regenerator to a low-temperature absorber, and low-temperature regenerating from the low-temperature absorber using a part of the absorbing solution discharged from the low-temperature solution conveying means as a driving fluid. 12. A method according to claim 1, further comprising the step of: providing a solution jet pump using an absorption solution sent to the vessel as a suction fluid, and supplying the absorption solution discharged from the solution jet pump to a low-temperature regenerator. Of 1
14. The absorption heat transformer according to any one of the above. 17. The absorption heat transformer according to claim 16, wherein the solution jet pump is provided such that a suction port thereof is located at a position lower than a solution discharge level of a solution supply device in the low-temperature regenerator. .