JPH0340207B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for circulating the solution between a generator that generates a working fluid from a solution and an absorber that absorbs the working fluid into the solution. In a concentration difference engine, an absorption refrigerator, etc. that supply water to an absorber, the energy of the solution returned from the generator to the absorber is recovered as part of the power source for circulating and pumping the solution. This invention relates to a power recovery system.

Conventionally, as this type of concentration difference engine, for example, the one shown in FIG. 1 is well known. That is, the concentration engine includes a generator 1 that heats a concentrated solution to generate a high-pressure working fluid, an absorber 2 that cools a dilute solution and absorbs the working fluid into the dilute solution, and the generator 1. A working fluid path 4 that uses the generated high-pressure working fluid as a drive source for driving the turbine 3 and then flows it to the absorber 2
and a dilute solution flow path in which the high temperature and high pressure dilute solution (part distributed in the upper layer of the entire solution) in the generator 1 after generating the working fluid is depressurized by the flow control valve 5 and then circulated back to the absorber 2. 6, and the low-temperature, low-pressure concentrated solution (part distributed in the lower layer of the entire solution) in the absorber 2 after absorbing the working fluid is fed and distributed to the generator 1 by a pump 8 driven by an electric motor 7. It is equipped with a concentrated solution flow path 9 and a heat exchanger 10 for exchanging heat between the solution flowing in both the solution flow paths 6 and 9, and the solution is circulated between the generator 1 and the absorber 2 by a pump 8. On the other hand, the turbine 3 is rotated by the pressure of the working fluid from the generator 1 to obtain output. Note that 1a is a heat source for heating the concentrated solution in the generator 1, 2a is a cooling water pipe 2b for cooling the dilute solution in the absorber 2,
. . . is a spout that spouts the dilute solution from the dilute solution flow path 6 into the absorber 2 in a shower shape.

By the way, in such a conventional concentration difference engine, the high-pressure dilute solution that is returned from the generator 1 to the absorber 2 is depressurized by the flow control valve 5 midway through the flow, as described above, to waste the energy of the dilute solution. This is a big loss in terms of effective energy use.

Therefore, a liquid turbine is provided in place of the pressure reducing flow control valve 5, and the liquid turbine is connected to the pump 8.
It is conceivable that the power of the pump 8 can be reduced by configuring a small and simple-structured turbine pump that is directly connected coaxially with the pump 8, thereby rotating the liquid turbine of the turbine pump with a high-pressure diluted solution.

However, in that case, since the flow rate ratio Gt/Gp between the liquid turbine and the pump 8, that is, the ratio of the amount of solution flowing through each of the liquid turbine and the pump 8 per constant rotation speed, is constant, the operating conditions of the engine are There is a problem that the number is limited to a single number. That is, to explain this in detail, the working fluid weight concentration ξ in a saturated solution is determined by its temperature and pressure. Therefore, if the concentrations of the concentrated solution and dilute solution are respectively ξ _s and ξ _w , then the concentrated solution flow rate (weight flow rate) Gs required to generate, for example, 1 kg of working fluid is: Gs = 1 - ξ _w / ξ _s −ξ _w . On the other hand, similarly, the dilute solution flow rate Gw is the value obtained by subtracting the working fluid generation amount (=1 kg) from the concentrated solution amount Gs, so Gw=Gs-1. Therefore, the rare/concentrated solution flow rate ratio Gw/Gs is Gw/Gs=1-1/Gs=1-ξ _s /1-ξ _w (0<Gw/Gs<1), and its value is the concentration of the solution ξ _s and ξ _w , in other words, the temperature and pressure in the generator 1 and absorber 2. This is illustrated in FIGS. 4 and 5. Therefore, due to fluctuations in engine operating conditions, the rare/concentrated solution flow rate ratio may change.
Gw/Gs is the turbine/pump flow rate ratio Gt/
When the value becomes smaller than Gp (a certain value), the dilute solution flows from the generator 1 to the absorber 2 more than necessary, and the internal liquid level of the generator 1 decreases, resulting in a so-called empty cooking state. The pressure of the working fluid decreases due to the outflow, and the driving force to the turbine 3, that is, the engine output becomes insufficient. In other words, the liquid turbine acts as a pump. On the other hand, the dilute/concentrated solution flow rate ratio GW/Gs is the turbine/pump flow rate ratio.
If it becomes larger than Gt/Gp, both the internal liquid level height and internal pressure of the generator 1 will rise, and the liquid turbine will have excessive resistance. Therefore, in either case, the engine cannot be operated stably. do not have.

The present invention has been made in view of these points,
One of the purposes is that when the turbine-pump flow rate ratio of a turbine pump in which a liquid turbine and a pump are directly connected is constant as described above, the turbine-pump flow rate ratio can be adjusted to the operating conditions of a concentration difference engine, etc. Set the flow rate ratio of dilute solution to concentrated solution to the minimum value that can be predicted within the range, and allow the surplus flow rate of dilute solution or concentrated solution due to changes in operating conditions to bypass the turbine of the turbine pump or the pump. By doing so, the aim is to maintain the balance of the entire system and allow the liquid turbine to perform its original turbine action, thereby achieving stable recovery of power for driving the pump over a wide range of operating conditions such as a concentration difference engine. .

To achieve this objective, the first invention of the present application includes a generator that heats a solution to generate a working fluid, an absorber that cools the solution and absorbs the working fluid into the solution, and A working fluid flow path that flows the working fluid generated in the generator to the absorber, a dilute solution flow path that flows the dilute solution in the generator after generating the working fluid to the absorber, and a A turbine pump in which a concentrated solution flow path through which the concentrated solution in the absorber flows into the generator, a turbine interposed in the dilute solution flow path, and a pump interposed in the concentrated solution flow path are directly connected coaxially. In a concentration differential engine, an absorption refrigerator, etc., which comprises an electric motor that drives the turbine pump, the turbine pump has a flow rate ratio of the turbine pump that is approximately equal to the minimum dilute/concentrated solution flow rate ratio within the range of operating conditions. This system uses a coaxial direct-coupled turbine pump, and has a bypass flow path in either the turbine or the pump. This compensates for the discrepancy between the dilute/concentrated solution flow rate ratio, which changes in response to fluctuations in the operating conditions of the concentration difference engine, and the constant turbine pump flow rate ratio, allowing the turbine of the turbine pump to function normally. It was made to be done.

Another object of the present invention is to increase or decrease the flow rate of the solution bypassing the turbine or pump of the turbine pump described above in accordance with the internal solution amount of the generator or absorber, so that the operating conditions can be changed. Even if the rare/concentrated solution flow rate ratio changes, the change is compensated for by changing the bypass solution flow rate, so that the liquid turbine always stably performs its original turbine action. The aim is to more reliably and stably recover power for driving the pump under a wide range of operating conditions such as the above.

In order to achieve this second object, the configuration of the second invention of the present application is such that the turbine provided in the dilute solution flow path and the pump provided in the concentrated solution flow path are coaxially and directly connected, as described above. In a concentration differential engine, an absorption refrigerator, etc. equipped with a turbine pump, a turbine pump having a turbine-pump flow rate approximately equal to the minimum dilute/concentrated solution flow rate ratio within the operating condition range is used as the turbine pump, Furthermore, a bypass flow path that bypasses either the turbine or the pump of the turbine pump and has a flow rate control valve, and a liquid level detector that detects the internal liquid level height of the generator or absorber; A control device is provided that receives the output of the liquid level detector and controls the opening and closing of the flow control valve of the bypass flow path so as to maintain the internal liquid level height of the generator or absorber within a constant or predetermined range. be. As a result, the difference between the dilute/concentrated solution flow rate ratio, which changes in response to fluctuations in the operating conditions of the concentration difference engine, etc., and the constant turbine/pump flow rate ratio can be automatically compensated for, and the turbine of the turbine pump This ensures that the turbine operates normally.

Hereinafter, two embodiments in which the present invention is applied to a concentration difference engine will be described in detail with reference to FIGS. 2 and 3, respectively. The basic configuration of the concentration difference engine has been explained with reference to FIG. 1, so the same parts as in FIG. 1 are given the same reference numerals and detailed explanation thereof will be omitted.

FIG. 2 shows a first embodiment, in which 1 is a generator equipped with a heat source 1a, 2 is an absorber equipped with a cooling water pipe 2a, and the generator 1 and absorber 2 are connected to a working fluid flow path 4. A turbine 3 is interposed in the middle of the working fluid passage 4, and the turbine 3 is operated by the pressure of the working fluid. The output of the concentration difference engine is obtained by driving the rotation. Furthermore, a portion of each of the solution flow paths 6 and 9 is polymerized with each other to constitute a heat exchanger 10.

Further, reference numeral 11 denotes a turbine pump in which a liquid turbine 12 and a pump 13 are coaxially and integrally directly connected, and the liquid turbine 12 is connected to the heat exchanger 10.
A pump 13 is provided in the dilute solution channel 6 on the more downstream side (absorber 2 side), and a pump 13 is provided in the concentrated solution channel 9 on the upstream side than the heat exchanger 10 (also on the absorber 2 side). Further, the turbine pump 11 is connected to an electric motor 7 through its pump 13, and the motor 7 operates the pump 13 to pump the concentrated solution in the absorber 2 to the generator 1. The liquid turbine 12 is rotationally driven by the hydraulic pressure of the dilute solution contained therein, thereby assisting the rotational force of a pump 13 (electric motor 7) which is integrated with the liquid turbine 12. The turbine-pump flow rate ratio Gt/Gp in the turbine pump 11, that is, the flow rate ratio of the dilute and concentrated solutions flowing through each of the liquid turbine 12 and the pump 13 per constant rotation speed, is within the operating condition range of the concentration difference engine. Rare/concentrated solution flow rate ratio
It is set to a value that is approximately equal to the minimum value of Gw/Gs, that is, the minimum value of the flow rate ratio of the rare and concentrated solutions flowing through the rare and concentrated solution flow paths 6 and 9, respectively, when the engine operating conditions change variously. .

Further, the liquid turbine 1 of the turbine pump 11
2. The liquid turbine 12 is connected between the dilute solution flow path 6 on the upstream and downstream sides.
The bypass flow path 14 is provided with an electrically operated flow control valve 15 that opens and closes so as to increase or decrease the flow rate of the dilute solution flowing through the bypass flow path 14.

On the other hand, the generator 1 includes a differential pressure detector for detecting the internal liquid level height, an electrical conductivity detector, and a float type 2
A liquid level detector 16 consisting of point detection or the like is attached, and the output of the liquid level detector 16 is sent to the control device 1 which controls the operation of the flow rate control valve 15 of the bypass flow passage 14.
7 is input connected. That is, the control device 17 controls the opening and closing of the flow rate control valve 15 in response to the output signal from the liquid level detector 16, and when the internal liquid level height of the generator 1 is lower than a predetermined value, the opening degree of the flow rate control valve 15 is changed. The internal liquid level of the generator 1 is reduced by reducing the flow rate of the dilute solution flowing through the bypass flow path 14, while increasing the opening degree of the flow rate control valve 15 to increase the flow rate of the dilute solution when the flow rate is higher than a predetermined value. It operates to keep the height constant or within a predetermined range. Regarding the operation of this control device 17, the output of the liquid level detector 16 is used as a continuous electric signal, and proportional, differential, integral, etc. control is performed based on this signal to adjust the internal liquid level height of the generator 1. Ideally, the liquid level should be kept constant, but if there are no other problems, ON-OFF control with a predetermined width may be performed to maintain the liquid level within a predetermined range.

Next, to explain the operation of the above embodiment,
When the turbine pump 11 is operated by the motor 7 while the heat source 1a of the generator 1 is operated and cooling water is flowing through the cooling water pipe 2a of the absorber 2, the low-pressure concentrated solution in the absorber 2 becomes a concentrated solution. The heat source 1a is pumped through the flow path 9 to the generator 1.
This heating generates a high-temperature, high-pressure gaseous working fluid from the concentrated solution. This working fluid returns to the absorber 2 through the working fluid flow path 4 and along the way drives the turbine 3 to rotate, thereby generating the power of the concentration difference engine.

On the other hand, after this working fluid is generated, the high temperature and high pressure dilute solution in the generator 1 is refluxed into the absorber 2 through the dilute solution flow path 6 due to the pressure, and inside the absorber 2, the cooling water pipe 2a, it absorbs the working fluid from the working fluid flow path 4 and becomes a concentrated solution. While being refluxed from the generator 1 to the absorber 2 in this way, the dilute solution exchanges heat with the low-temperature concentrated solution in the concentrated solution flow path 9 in the heat exchanger 10 and becomes low temperature.
Thereafter, the liquid turbine 12 of the turbine pump 11 is driven to rotate to reduce the pressure. By driving this liquid turbine 12, the pump 13, that is, the motor 7
The driving force can be reduced.

In this case, since the turbine pump flow rate ratio Gt/Gp in the turbine pump 11 is set to be approximately equal to the minimum value of the rare/concentrated solution flow rate ratio Gw/Gs within the range of engine operating conditions (Gt/Gp ≦
Gw/Gs), the internal liquid level of the generator 1 tends to rise as the engine operates as described above. However, the liquid level detector 16 detects this liquid level height and outputs a liquid level height signal to the control device 17, and the control device 17 that receives this liquid level height signal responds to the bypass flow. The flow rate control valve 15 of the passage 14 is opened to a predetermined degree to allow a portion of the dilute solution to flow into the bypass passage 14. This allows the flow rate of the entire dilute solution to be
increases to correspond to the concentrated solution flow rate ratio Gw/Gs,
Therefore, the rise in the internal liquid level height of the generator 1 is controlled and an equilibrium state is achieved.

Then, when the operating condition of the engine changes from this equilibrium state and the dilute/concentrated solution flow rate ratio Gw/Gs changes, the opening degree of the flow control valve 15 changes in response to the change, as described above. The dilute solution flow rate is increased or decreased, and a new equilibrium state is reached.

Therefore, even if the engine operating conditions change and the dilute/concentrated solution flow rate ratio Gw/Gs increases or decreases, only the dilute solution flow rate is adjusted in the bypass flow path 14 to correspond to the change. Therefore, the flow rate of the dilute solution from the turbine pump 11 to the liquid turbine 12 is always approximately constant, that is, the liquid turbine 12 is always driven at the flow rate at the maximum efficiency point, and there is no pumping action or excessive resistance. Therefore, the energy of the high-pressure dilute solution can be stably and reliably recovered and used to power the pump 13.

In addition, since the dilute solution flow rate is changed according to the liquid level height of the solution in the generator 1 to compensate for the change in the dilute/concentrated solution flow rate ratio Gw/Gs, even if the engine operating conditions suddenly change, the dilute solution flow rate can be changed quickly. The engine system can be brought into equilibrium, and the engine can therefore be operated stably and automatically.

Furthermore, due to changes in engine operating conditions,
Bypass flow path 14 changes in concentrated solution flow rate ratio Gw/Gs
Since the compensation is made by adjusting and controlling the flow path area of , the turbine-pump flow rate ratio can be kept constant, and a direct-coupled turbine pump 11 that is small and has a simple structure can be used.

FIG. 3 shows a second embodiment. In the first embodiment, the dilute solution flow rate is adjusted according to the internal liquid level height of the generator 1.
In contrast to increasing/decreasing Gw, the concentrated solution flow rate Gs is also controlled increasing/decreasing (the same parts as in Figure 2 are given the same reference numerals and detailed explanations are omitted). ).

That is, in this embodiment, the bypass flow rate 14'
are provided to connect the concentrated solution flow path 9 on the upstream and downstream sides of the pump 13 of the turbine pump 11, and a part of the concentrated solution discharged from the pump 13 is transferred to the suction side of the pump 13 through the bypass flow path 14'. It is made to return to the ground. Further, the opening degree of the flow rate control valve 15' provided in the bypass passage 14' is controlled by a control device 17' which operates in response to the output of the liquid level detector 16. The rest of the structure is the same as that of the first embodiment.

Therefore, in this embodiment, when the dilute/concentrated solution flow rate ratio Gw/Gs changes due to a change in engine operating conditions, the liquid level detector 16 and the control device 17' are activated in the same manner as in the first embodiment. When activated, the opening degree of the flow rate control valve 15' of the bypass channel 14' is adjusted to increase or decrease, thereby changing the flow rate of the concentrated solution flowing through the bypass channel 14', that is, the return flow rate of the concentrated solution, and increasing the overall concentration. The solution flow rate Gs is changed to correspond to the new dilute to concentrated solution flow rate ratio Gw/Gs, so that variations in the liquid level in the generator 1 are controlled. Therefore, the same effects as in the first embodiment can be achieved.

In both of the above embodiments, the internal liquid level of the generator 1 is detected and the control devices 17, 17' are controlled accordingly.
Although the opening degree of the flow rate control valves 15, 15' is controlled by the above, it is also possible to detect the internal liquid level height of the absorber 2 and perform the same control as described above accordingly. It may be selected as appropriate.

In addition, the present invention is applicable not only to a concentration difference engine, but also to
Of course, the present invention can also be applied to absorption refrigerators and the like.

As explained above, according to the first invention of the present application, the generator and the absorber are provided, and the high-pressure working fluid flowing from the generator to the absorber is used for output, while the turbine and the pump are coaxially connected. A concentration difference engine or an absorption engine that flows the dilute solution in the generator to the absorber through the turbine of a turbine pump directly connected to the engine, and flows the concentrated solution in the absorber to the generator through the pump. In a type refrigerator, etc., a turbine pump having a turbine-to-pump flow rate approximately equal to the minimum dilute/concentrated solution flow rate ratio within the operating condition range of a concentration difference engine, etc. is used as the turbine pump, and the turbine of the turbine pump is Alternatively, by providing a bypass flow path that bypasses either one of the pumps, even if the operating conditions of the engine etc. change and the ratio of dilute/concentrated solution flow rates changes, the solution will bypass the bypass flow path by the amount of the change. Since it is possible to control changes in the internal liquid level of the generator or absorber by compensating for the flow, the turbine of the turbine pump can be used while using a small and simple turbine pump. It is possible to operate stably and efficiently under a wide range of engine operating conditions and recover the power for driving the pump, thereby reducing the power used in concentration difference engines, absorption chillers, etc. It is possible to achieve this goal.

Further, according to the second invention of the present application, a flow control valve is provided in the bypass flow path, and the opening degree of the flow control valve is controlled according to the internal liquid level height of the generator or absorber. By doing so, the flow rate of the solution flowing through the bypass flow path is adjusted, and the turbine of the turbine pump can be operated more stably, and the power of the concentration difference engine, absorption refrigerator, etc. can be reliably reduced. It is something that can be done.

[Brief explanation of the drawing]

Figure 1 is a schematic illustration of a conventional concentration difference engine.
2 is a diagram equivalent to FIG. 1 showing the first embodiment of the present invention, FIG. 3 is a diagram equivalent to FIG. 1 showing the second embodiment,
Figure 4 is an explanatory diagram showing an example of the correlation between the temperature and pressure inside the absorber and the rare/concentrated solution flow rate ratio when the temperature and pressure inside the generator are kept constant, and Figure 5 is the temperature and pressure inside the absorber. FIG. 2 is an explanatory diagram showing an example of the correlation between the temperature and pressure inside the generator and the rare/concentrated solution flow rate ratio when the temperature and pressure are kept constant. DESCRIPTION OF SYMBOLS 1... Generator, 2... Absorber, 3... Turbine, 4... Working fluid flow path, 6... Dilute solution flow path, 7
...Electric motor, 9... Concentrated solution channel, 10... Heat exchanger, 11... Turbine pump, 12... Liquid turbine, 13... Pump, 14, 14'... Bypass channel, 15, 15 '...Flow control valve, 16...
...Liquid level detector, 17, 17'...control device.

Claims (1)

[Claims] 1. A generator 1 that heats a solution to generate a working fluid, an absorber 2 that cools a solution and absorbs the working fluid into the solution, and a generator 1 that generates a working fluid. a working fluid flow path 4 that allows fluid to flow through the absorber 2;
A dilute solution flow path 6 that allows the dilute solution in the generator 1 after generating the working fluid to flow through the absorber 2, and a dilute solution flow path 6 that allows the concentrated solution in the absorber 2 to flow into the generator 1 after absorbing the working fluid. A turbine pump 11 in which a concentrated solution flow path 9, a turbine 12 provided in the dilute solution flow path 6, and a pump 13 provided in the concentrated solution flow path 9 are directly connected coaxially; and a turbine pump 11 for driving the turbine pump 11. In a concentration difference engine, an absorption refrigerator, etc., which is composed of an electric motor 7, the turbine pump 11 has the minimum dilute/concentrate solution flow rate ratio within the operating condition range.
Turbine/pump flow rate ratio Gt/ approximately equal to Gw/Gs
Using a coaxial direct-coupled turbine pump with Gp,
A power recovery system characterized in that either the turbine 12 or the pump 13 is provided with a bypass passage 14, 14'. 2. A generator 1 that heats a solution to generate a working fluid, an absorber 2 that cools the solution and absorbs the working fluid into the solution, and a generator 1 that supplies the working fluid generated in the pre-generating generator 1 to the absorber 2. A working fluid flow path 4 that circulates;
A dilute solution flow path 6 that allows the dilute solution in the generator 1 after generating the working fluid to flow through the absorber 2, and a dilute solution flow path 6 that allows the concentrated solution in the absorber 2 to flow into the generator 1 after absorbing the working fluid. A turbine pump 11 in which a concentrated solution flow path 9, a turbine 12 provided in the dilute solution flow path 6, and a pump 13 provided in the concentrated solution flow path 9 are directly connected coaxially; and a turbine pump 11 for driving the turbine pump 11. In a concentration differential engine, an absorption refrigerator, etc., equipped with an electric motor 7, the turbine pump 11 has the minimum dilute/concentrate solution flow rate ratio within the operating condition range.
Turbine/pump flow rate ratio Gt/ approximately equal to Gw/Gs
Using a turbine pump with Gp, furthermore, the turbine 12 of the turbine pump 11 or the pump 13
Bypass either one of the flow control valves 1 and 1
a bypass channel 14, 14' having 5, 15';
A liquid level detector 16 detects the internal liquid level height of the generator 1 or absorber 2, and receives the output of the liquid level detector 16 to detect the internal liquid level height of the generator 1 or absorber 2. A power recovery system comprising: a control device 17, 17' for controlling the opening and closing of the flow control valves 15, 15' of the bypass passages 14, 14' so as to maintain the flow rate within a constant or predetermined range.