JPH065144B2 - Absorption heat pump controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention operates by keeping the pressure and temperature in the generator and the condenser lower than the pressure and temperature in the evaporator and the absorber, and The present invention relates to a control device for an absorption heat pump (hereinafter referred to as an absorption heat pump of this type) that takes out a heated fluid having a temperature higher than that of a heat source fluid supplied to an evaporator from an absorber.

(B) Prior Art Since this type of absorption heat pump operates while keeping the pressure inside the generator and the condenser lower than the pressure inside the evaporator and the absorber, it is described, for example, in JP-A-58-69372. As described above, the generator and the condenser are usually arranged below the evaporator and the absorber. Then, when the operation is stopped, the refrigerant in the absorber is absorbed and the diluted absorbent having a low concentration is caused to flow into the concentrated absorbent in the generator to dilute the concentrated absorbent. In addition, for example, JP-A-5
As described in JP-A-8-31262, when the operation is stopped, the refrigerant liquid in the evaporator or the condenser is blown into the concentrated absorption liquid in the generator to dilute the concentrated absorption liquid. By diluting the absorbing solution in this manner, crystallization of the absorbing solution (lithium bromide aqueous solution) after the operation is stopped can be prevented.

Then, when restarting the operation, first the pump (hereinafter referred to as the absorption liquid pump) that sends the diluted absorption liquid (hereinafter referred to as the diluted liquid) is operated to send the diluted liquid from the generator to the absorber, and the diluted liquid is absorbed. While flowing down from the reactor to the generator via the solution heat exchanger, it is sprayed on the heater built into the generator to separate the refrigerant vapor, and the separated refrigerant vapor is liquefied in the condenser. Next, when the amount of the refrigerant liquid in the refrigerant liquid reservoir of the condenser becomes a predetermined value or more, the pump (hereinafter referred to as the second refrigerant pump) sends the refrigerant liquid to the refrigerant liquid reservoir of the evaporator, and then the refrigerant liquid in the refrigerant liquid reservoir When the amount of the refrigerant liquid exceeds a predetermined value, the pump (hereinafter referred to as the first refrigerant pump) causes the refrigerant liquid to flow back to the evaporator and is sprayed and evaporated on the heat supply device built in the evaporator, so that the steady operation is performed. I have to.

In the case of such a method of starting the operation, immediately after the operation is restarted, since the temperature of the heated fluid flowing into the absorber is low together with the fact that the refrigerant is not evaporated in the evaporator,
The pressure in the evaporator and absorber hardly rises.

Therefore, the pressure difference between the absorber and generator remains small,
A small amount of dilute liquid is sprayed to the heater while flowing down from the absorber to the generator via the solution heat exchanger, and the separation of the refrigerant in the generator is small, and the refrigerant liquid in the refrigerant liquid reservoir of the condenser is small. It takes a long time for the amount to exceed the predetermined value. Further, the refrigerant liquid is sent from the condenser to the evaporator, the refrigerant liquid amount in the refrigerant liquid reservoir of the evaporator becomes a predetermined value or more, the evaporation of the refrigerant in the evaporator is started, and the pressures in the evaporator and the absorber are increased. It took a long time to start rising.

As described above, the conventional absorption heat pump of this type has a drawback that it takes a long time from the restart of the operation to the steady operation, and the start-up of the operation is slow.

(C) Object of the Invention The present invention has an object to provide an absorption heat pump of this type, which can accelerate the start-up of operation.

(D) Structure of the Invention In the absorption heat pump of the present invention, the bypass pipe for circulating the concentrated liquid to the generator or the bypass pipe for the dilute liquid for bypassing the solution heat exchanger is provided in the evaporator. It was configured to adjust the amount of the absorption liquid sprayed to the heater built in the generator by opening and closing the control valve provided in the bypass pipe with the signal of the detector that detects the pressure or the temperature of the refrigerant in the evaporator. It is a thing.

According to the present invention, the restart of the operation in which the pressure difference between the absorber and the generator is small and the amount of the absorbing liquid sprayed to the heater of the generator is small while flowing down from the absorber to the generator via the solution heat exchanger is restarted. Immediately thereafter, as compared with the conventional absorption heat pump of this type, a larger amount of the absorption liquid can be sprayed to the heater via the bypass pipe, so that the generation amount of the refrigerant vapor in the generator can be increased.

Therefore, in this type of absorption heat pump equipped with the control device of the present invention, it takes less time than the conventional absorption heat pump of this type even if the amount of the refrigerant liquid in the refrigerant reservoir becomes a predetermined value or more, It is possible to shorten the time from the restart of the operation until the refrigerant evaporates in the evaporator and the pressure in the evaporator and the absorber rises, and the start-up of the operation can be accelerated compared with the conventional absorption heat pump of this type.

(E) Embodiments The drawings are schematic configuration explanatory views showing an embodiment of a control device for an absorption heat pump of this type according to the present invention, wherein (1) is a lower stage composed of a generator (2) and a condenser (3). Side generation condensation stage,
(4) is an upper evaporative absorption stage consisting of an evaporator (5) and an absorber (6), (7) is a solution heat exchanger, (8) and (9) are first and second refrigerant pumps, respectively. (10) is an absorption liquid pump, these devices are ducts (11), (12) through which the refrigerant vapor flows, pipes (13), (14) to which the refrigerant liquid is sent, refrigerant liquid recirculation pipe (15), ( 16), pipes to which concentrated liquid is sent (17), (18), (19), pipes through which dilute liquid flows (2)
They are connected by 0) and (21) to form a circulation path for the refrigerant (water) and the absorption liquid (lithium bromide aqueous solution) similar to the conventional absorption heat pump of this type. Incidentally, (22) is a heat exchange coil built in the solution heat exchanger (7).

(23) is a heater built in the generator (2), (24) is a cooler built in the condenser (3), (25) is a heat source built in the evaporator (5),
(26) is a device to be heated built in the absorber (6), and (27), (2
8) is a pipe for flowing a heat source fluid such as waste hot water and waste steam connected to the heater (23), and (29) and (30) are cooling fluids such as cooling water and cooling air connected to the cooler (24). , (31) and (32) are pipes for flowing heat source fluid such as waste hot water and waste steam connected to the heat supply device (25), and (33) and (34) are connected to the heated device (26). It is a pipe through which heated fluid such as hot water or steam flows.

(35), (36) is a generator (2), respectively, a sprayer of the absorption liquid provided in the absorber (6), (37) is a sprayer of the refrigerant liquid provided in the evaporator (5), 38) and (39) are the reservoirs of the generator (2) and the absorber (6) respectively, and (40) and (41) are the condenser (3) and evaporator (5), respectively.
(42), (43) are eliminators.

(SW ₁ ) is the liquid level switch provided in the solution reservoir (38),
(C) is a liquid level controller provided in the refrigerant liquid reservoir (40), (S
W ₂ ) is a liquid level switch provided in the refrigerant liquid reservoir (41),
(V ₀ ) is a flow rate control valve for the refrigerant liquid provided in the pipe (14), and the liquid level switches (SW ₁ ), (SW ₂ ), and the liquid level controller (C) respectively set the absorption liquid pump (10), 1 refrigerant pump (8),
The second refrigerant pump (9) is controlled to start and stop so that the liquid level is maintained between the upper and lower limit set levels, and the liquid level controller (C) opens the flow control valve (V ₀ ). The flow rate of the refrigerant liquid sent from the condenser (3) to the evaporator (5) is controlled by controlling the temperature.

In the absorption heat pump (hereinafter referred to as this machine) configured as described above, during steady operation, the generated condensation stage (1) side operates at a lower pressure than the evaporative absorption stage (4) side, and the absorber (6) The concentrated liquid sprayed to the device to be heated (26) heats the fluid to be heated in the device to be heated (26) by the heat generated when absorbing the refrigerant, and the pipe (34)
To the temperature of the heat source fluid (eg waste steam) (eg 80 ° C)
The heated fluid (for example, hot water) at a higher temperature (for example, 116 ° C.) is taken out.

(44) is a tube for blowing coolant fluid having an on-off valve (V _1), open-off valve prior to stopping the operation of the machine (V _1), this type of conventional absorption heat pump (hereinafter, Like the conventional machine), the refrigerant liquid in the refrigerant liquid reservoirs (40) and (41) is blown to the lower limit setting level of the liquid level by the second and first refrigerant pumps (9) and (8), and the liquid reservoir ( The concentrated liquid in 38) is diluted and the absorption liquid is diluted.

Reference numeral (45) is an absorption liquid bypass pipe connecting the absorption liquid pump (10) discharge side pipe (18) and the sprayer (35) inlet side pipe (21), and a control valve (V ) Is prepared. (S ₁ )
(S ₂ ) is a refrigerant liquid reservoir (41), a detector for detecting the temperature of the refrigerant liquid in the pipe (16), (S ₃ ) and (S ₄ ) are an evaporator (5) and an absorber (6), respectively. ) Is a detector that detects the pressure inside
The control valve (V) is controlled to be opened and closed by a signal from any of these detectors.

Next, an operation example at the time of starting the operation of this machine will be described in comparison with the operation of the conventional machine having no bypass pipe (45).

In this machine, the pressure on the evaporative absorption stage (4) side is, for example, about 60 mmHg, which is low immediately after the start of operation, and the value of the refrigerant liquid in the pipe (16) and the refrigerant liquid reservoir (41) is low. Since the temperature is, for example, about 42 ° C. and its value is low, the detector (S ₁ ),
The control valve (V) is fully opened by the signal of (S ₂ ), (S ₃ ) or (S ₄ ), and the absorbent discharged from the absorbent pump (10) is absorbed by the absorber (6) side and the generator (2). ) Side and split. And
The absorption liquid that has flowed to the generator (2) side and the absorption liquid that flows down from the absorber (6) due to the head fall by the sprayer (35) to the heater (23)
And the refrigerant vapor is separated. This refrigerant vapor is liquefied in the condenser (3) and the liquid level in the refrigerant liquid reservoir (40) rises, and when the liquid level reaches or exceeds a predetermined level, the second refrigerant pump (C) receives a signal from the liquid level controller (C). 9) operates and the refrigerant liquid is sent to the evaporator (5) side.

On the other hand, in the conventional machine, the entire amount of the absorbing liquid discharged by the absorbing liquid pump (10) is sent to the absorber (6). Then, the absorbing liquid that has flowed into the absorber (6) is sprayed to the heater (23) while flowing down again to the generator (2) side due to the drop. However, the pressure difference between the absorber (6) and the generator (2) is small at the beginning of operation, and the amount of absorbed liquid flowing down to the generator (2) side is small. Compared to the generator (2), the amount of refrigerant vapor generated is small.

Therefore, in this machine, the refrigerant sump (40) of the condenser (3)
It takes less time than the conventional machine until the liquid level in the inside reaches a predetermined level or more, and the refrigerant liquid is sent to the evaporator (5) side faster than the conventional machine.

Then, in this machine, the refrigerant liquid is sent to the evaporator (5) side to raise the liquid level in the refrigerant liquid reservoir (41), and when the liquid level becomes equal to or higher than a predetermined level, the liquid level switch (SW ₂ ) Signal, the first refrigerant pump (8) is activated, the refrigerant liquid is sprayed on the heat supplier (25), and the evaporation of the refrigerant in the evaporator (5) is started.
When the refrigerant starts to evaporate, the pressure on the evaporative absorption stage (4) side gradually rises, and the non-evaporated refrigerant in the evaporator (5) is also supplied to the heat supply device (25).
To be repeatedly heated by the pipe (16), refrigerant sump (4
The temperature of the refrigerant liquid in 1) gradually rises. And the absorber
The pressure difference between the generator (6) and the generator (2) increases, and the flow rate of the absorbing liquid flowing from the absorber (6) to the generator (2) via the solution heat exchanger (7) gradually increases. Evaporation and absorption stage (4) side pressure and pipe (1
6), accompanied turned in detector temperature of the refrigerant liquid in the reservoir the refrigerant fluid (41) rises _{(SW 1),} (SW 2), the control valve by a signal (SW ₃₎ or (SW ₄₎ (V ) Is squeezed in the closing direction, and a predetermined value (for example, pressure of 234 mmHg, 70 ° C)
Control fluid (V), the control valve (V) is fully closed.
Then, the machine shifts to steady operation.

The control valve (V) is turned on instead of the valve that controls the opening degree.
It is also possible to use a -OFF valve. Further, the bypass pipe (45) may be connected to the pipe (19) instead of being connected to the pipe (18).

Further, instead of the bypass pipe (45), a bypass pipe (45 ') with a control valve (V) may be provided. This bypass pipe (4
5 ') is the absorption liquid absorber (6) outlet side pipe (20) and sprayer (35)
A pipe (21) on the inlet side is connected to allow the absorbing liquid to flow down to the generator (2) side by bypassing the heat exchange coil (22) having a large flow resistance.

Also, in this machine, the temperature of the heat source fluid and the cooling fluid fluctuates, and the pressure difference between the evaporative absorption stage (4) and the generated condensation stage (1) fluctuates, and the absorber (6) moves to the solution heat exchanger ( Even if the flow rate of the absorbing liquid flowing down to the generator (2) via 7) changes, the control valve (V)
By controlling the opening of the generator (2), it is possible to reduce fluctuations in the amount of the absorption liquid sprayed onto the heater (23) of the generator (2), and at the same time, the generator (2) and the absorber
(6) There is also an advantage that uneven distribution of the absorbing liquid can be prevented and stable operation can be continued.

(F) Effects of the Invention As described above, in the absorption heat pump of this type, according to the present invention, the bypass pipe is used at the start of operation when the flow rate of the absorbing liquid flowing from the absorber to the generator via the solution heat exchanger is small. Since a large amount of absorbing liquid can be sprayed to the heater of the generator via the, the amount of refrigerant vapor generated in the evaporator at the start of operation can be increased. Therefore, according to the present invention,
It takes less time than the conventional absorption heat pump of this kind even if the amount of the refrigerant liquid in the refrigerant liquid reservoir becomes a predetermined value or more, and the time from the start of operation until the refrigerant starts to evaporate in the evaporator can be shortened, The start-up of the operation can be made earlier than that of the conventional absorption heat pump of this type.

[Brief description of drawings]

The drawings are schematic structural explanatory views showing an embodiment of a control device for an absorption heat pump of this type according to the present invention. (1) ... Generating condensation stage, (2) ... Generator, (3) ... Condenser, (4) ... Evaporation and absorption stage, (5) ... Evaporator, (6) ... Absorber, (7) ... Solution heat Exchanger, (8), (9) ... First and second refrigerant pumps, (10) ... Absorption liquid pump, (16), (18), (19), (20), (21) ... Pipe, ( 22) ... coil for heat exchange, (23) ... heater, (24) ... cooler, (25) ... heater, (26) ... heated device, (35) ... sprayer, (38), ( 39) ... Solution reservoir, (40), (41) ... Refrigerant liquid reservoir, (45), (45 ') ... Bypass pipe, (C) ... Controller, (SW ₁ ), (SW ₂ ) ... Liquid level switch , (S ₁ ), (S ₂ ) (S ₃ ), (S ₄ ) ... Detector, (V) ... Control valve.

Claims (1)

[Claims] 1. A generator, a condenser, and an evaporator for supplying a heat source fluid to a generator and an evaporator while flowing a cooling fluid to the condenser to take out a heated fluid having a temperature higher than that of the heat source fluid from the absorber. An absorption heat pump consisting of an absorber and a solution heat exchanger connected by pipes, which connects the discharge side of the pump that sends the absorbing liquid from the generator to the absorber and the inlet side of the absorbing liquid sprayer provided in the generator. By-pass pipe for liquid, or by-pass pipe for absorbing liquid that connects the absorber outlet side of the absorbing liquid and the inlet side of the spreader so that the absorbing liquid bypasses the solution heat exchanger and flows down from the absorber to the spreader. Is provided and a control valve is provided in this bypass pipe, and the opening and closing of the control valve is controlled by a signal from a detector that detects the pressure in the evaporator or the temperature of the refrigerant in the evaporator. Heat pump controller.