JPH0639984B2 - Double-effect absorption refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to improvement of a double-effect absorption refrigerator.

(B) Conventional technology In a double-effect absorption refrigerator, when the pressure difference between the devices is smaller than a specified value (for example, at the start of operation or when the load is low), the high temperature generator and the separator side The absorption liquid flowing down to the low temperature generator side via the high temperature solution heat exchanger and the absorption liquid flowing down from the low temperature generator side to the absorber side via the low temperature solution heat exchanger will deteriorate, so May be mixed into the refrigerant circulation path (carry over).

Therefore, in the double-effect absorption refrigerator, as a conventional technique for preventing carryover, the absorption liquid flow path that bypasses these solution heat exchangers having large flow resistance is provided at a low temperature between the separator and the low temperature generator. Means for disposing between the generator and the absorber, or between the high temperature generator and the absorber (for example, JP-B-58-24706 and JP-B-58-10).
663).

(C) Problems to be Solved by the Invention In the conventional techniques as described above, although it is possible to prevent uneven distribution of the absorbing liquid in the high temperature generator or the separator, or the low temperature generator to prevent carryover, Since the absorbing liquid of No. 2 flows into the absorber on the low temperature and low pressure side as it is, there is a drawback that the absorbing capacity of the absorber is lowered and the operation efficiency at the time of partial load is deteriorated.

In view of such problems of the conventional art, the present invention provides a dual-effect absorption refrigerator that can prevent carryover and reduce a decrease in operating efficiency under partial load (particularly under low load). It is intended.

(D) Means for solving the problems The present invention, as a means for solving the above problems, a flow path of an absorbing solution with a solution pump from a low temperature generator to a low temperature solution heat exchanger, and a low temperature solution heat A dual-effect absorption refrigerator that has a flow path for absorbing liquid from the exchanger to the absorber and a controller that activates the solution pump when the physical quantity that changes in connection with the decrease in load reaches a set value. Is provided.

(E) Action In the means according to the present invention, for example, when the liquid level of the absorbing liquid in the low temperature generator reaches the upper limit set level at a low load, the solution pump operates to force the absorbing liquid in the low temperature generator to a low temperature. Since it has a function of sending it to the absorber via the solution heat exchanger, the absorbing liquid whose temperature has been lowered by the low temperature solution heat exchanger is scattered in the absorber. Therefore, it is possible to reduce the decrease in the absorption capacity of the absorber as compared with the conventional means in which the absorbent having a high temperature flows into the absorber as it is, and it is possible to prevent the decrease in the operating efficiency under a low load. When the liquid level of the low temperature generator reaches the lower limit setting level by the operation of the solution pump, the solution pump is stopped and cavitation of the solution pump is prevented.

(F) Example FIG. 1 is a schematic configuration explanatory view showing an example of a double-effect absorption refrigerator according to the present invention. (1) heats a rare absorption liquid by using combustion gas such as gas or oil. A high temperature generator, (2) a separator that separates the refrigerant vapor that has been heated in the high temperature generator (1) and has risen in the pumping pipe (3) from the absorption liquid, and (4) that separates it with a separator (2). A low-temperature generator that heats the absorption liquid by using the generated refrigerant vapor as a heat source to further concentrate it, and (5) is a condenser that cools the refrigerant flowing from the generator (1) and (4) with the cooler (6) and liquefies it. , (7) is an evaporator that obtains cold water for cooling from the heat exchanger (8) by utilizing the latent heat of spraying and vaporizing the refrigerant liquid from the condenser (5), and (9) is an evaporator A bubble pump that recirculates the refrigerant liquid that was not vaporized in the vessel (7), and (10) absorbs the refrigerant vapor in the vessel by spraying the concentrated absorbent that has separated the refrigerant in the generators (1) and (4). To lower the pressure inside the evaporator (7). An absorber designed to maintain and continuously supply cold water, (11) is an on-off valve (12)
And has a separator by opening the on-off valve (12) during heating.
Bypassing the high-temperature refrigerant in (2) into the shell (13), it is possible to take out hot water from the heat exchanger (8) during heating, and (14) is an absorber during such heating and cooling.
Pumps for sending the absorbing liquid sprayed to (10) to the high temperature generator (1), (15) and (16) are low temperature and high temperature solution heat exchangers, respectively, and these are pipes (17), (where refrigerant flows). 18), (19), absorption liquid flow pipe (20), (21), (22), (23), pumping pipe (3), bypass pipe
(11) and the overflow pipe (24) are connected to form a circulation path for the refrigerant and the absorbing liquid.

Further, (25) is a tube with a solution pump (P) attached between the low temperature generator (4) and the low temperature solution heat exchanger (15). In addition,
(26) and (27) are check valves provided in pipes (19) and (22), respectively (28)
Is a steam trap for the overflow pipe (24).

And (S ₁ ) is a liquid level detector provided in the low temperature generator (4),
The signal from the liquid level detector causes the solution pump (P) to be started and stopped via the controller (C). That is, the solution pump (P) operates when the liquid level reaches the upper limit setting level, and stops when the liquid level reaches the lower limit setting level.

In the double-effect absorption refrigerator configured in this way,
When the load is reduced and the heating of the high temperature generator (1) is stopped, the temperature and pressure inside the high temperature generator (1) and the separator (2) drop, and the high temperature solution heat is removed from the separator (2). The amount of absorbing liquid flowing to the low temperature generator (4) via the exchanger (16) is reduced. On the other hand, the pump (14) from the absorber (10) side to the high temperature generator (1), separator
An almost constant amount of absorbing liquid is sent to the (2) side (actually, the feeding amount of absorbing liquid increases as the pressure difference between the high temperature generator (1) and the absorber (10) becomes smaller). The liquid level in the separator (2) rises, and the absorbing liquid flows to the low temperature generator (4) via the overflow pipe (24). Further, when the heating of the high temperature generator (1) is stopped, the supply of the refrigerant vapor from the separator (2) which is the heat source of the low temperature generator (4) is also cut off, so the low temperature generator (4)
The internal temperature and pressure also decrease, and the amount of absorbing liquid flowing from the low temperature generator (4) to the absorber (10) via the low temperature solution heat exchanger (15) decreases. Therefore, the liquid level in the low temperature generator (4) gradually rises due to the absorbing liquid flowing in via the overflow pipe (24). Then, when the liquid level rises to the upper limit set level, the solution pump (P) operates, and the absorbing liquid passes through the pipe (25) from the low temperature generator (4) through the low temperature solution heat exchanger (15) to the absorber ( Sent to 10). In addition, when the liquid level in the low temperature generator (4) is lowered to the lower limit set level by sending the absorbing liquid by the solution pump (P), the solution pump (P) is stopped.

FIG. 2 is a schematic structural explanatory view showing another embodiment of the double-effect absorption refrigerator according to the present invention, and the same components as those shown in FIG. 1 are designated by the same reference numerals. In FIG. 2, (29) is an overflow pipe provided between the low temperature generator (4) and the absorber (10), and (S ₂ ) is a temperature detector provided in this overflow pipe (29), Further, (S ₃ ) and (S ₄ ) are temperature detectors provided in the separator (2) and the overflow pipe (24), respectively. Then, the temperature detector (S ₂ ) or the temperature detector (S
₄ ) signal, or the temperature detector (S ₃ ) and the temperature detector (S
_The solution pump (P) is controlled by the two signals ₄ ) via the controller (C).

In the embodiment shown in FIG. 2, for example, the load is reduced and the heating of the high temperature generator (1) is stopped, the absorbing liquid starts to flow in the overflow pipe (29), and the temperature detector (S ₂ ) senses it. When the temperature reaches the first set temperature (for example, 80 ° C.), the solution pump (P) is operated. Then, the liquid level of the low temperature generator (4) drops, and the absorption liquid stops flowing through the overflow pipe (29), and the temperature sensed by the temperature detector (S ₂ ) becomes the second set temperature (for example, 50).
When the temperature falls below ℃), the solution pump (P) is activated. Alternatively, when the absorption liquid starts to flow through the overflow pipe (24) and the temperature sensed by the temperature detector (S ₄ ) reaches a set temperature (for example, 80 ° C.) or higher, the solution pump (P) is activated and the overflow pipe (24)
The solution pump (P) is stopped when the absorption liquid stops flowing and becomes lower than the set temperature. Also a temperature detector
If the difference between the temperature sensed by (S ₃ ) and the temperature sensed by the temperature detector (S ₄ ) exceeds a set value (for example, 30 ° C), the overflow pipe (2
4) When the absorption liquid flows through the inside, activate the solution pump (P),
The solution pump (P) may be stopped when the value becomes less than the set value. Steam trap (28) in overflow pipe (24)
In the case where the steam trap is provided, it is preferable to detect the temperature difference before and after the steam trap.

As described above, in the double-effect absorption refrigerator according to the present invention, when the partial load is applied (particularly when the load is low), the low temperature generator (4) flows through the low temperature solution heat exchanger (15) to the absorber (10). Even when the flow rate of the absorbing liquid to be reduced decreases, the physical quantity that changes in relation to the load such as the liquid level in the low temperature generator (4) and the liquid temperature in the overflow pipe (24) is detected and the solution pump ( The overflow pipe (29) is activated because the concentrated absorbent liquid cooled by the low temperature solution heat exchanger (15) is forcibly sprayed to the absorber (10).
Compared to the conventional double-effect absorption refrigerator that directly flows the concentrated absorbent with high temperature to the absorber (10) on the low temperature and low pressure side, less flushing of the concentrated absorbent in the absorber (10),
Carryover is prevented, and the reduction in the absorption capacity of the absorber (10) is also alleviated to prevent the reduction in operating efficiency.
Further, even when the operation is started, it is possible to spray the absorption liquid in the low temperature generator (4) into the absorber (10) via the low temperature solution heat exchanger (15) by the solution pump (P). It is also possible to improve the startup performance at startup.

(G) Effect of the Invention The present invention is a double-effect absorption refrigerator configured as described above, and when the load is reduced to a partial load (especially when the load is low), the controller is a solution pump. Is activated, the concentrated absorbent in the low-temperature generator is forcibly cooled by the solution pump via the low-temperature solution heat exchanger and is sprayed into the absorber, so the absorption capacity of the absorber decreases and It is possible to reduce the flushing of the absorbing liquid, prevent carryover, and reduce the decrease in operating efficiency under partial load.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view showing an embodiment of a double-effect absorption refrigerator according to the present invention, and FIG. 2 is a schematic configuration explanatory view showing another embodiment of a double-effect absorption refrigerator according to the present invention. Is. (1) …… High temperature generator, (2) …… Separator, (4) …… Low temperature generator, (5) …… Condenser, (7) …… Evaporator, (10) …… Absorber,
(14) …… Pump, (15) …… Cryogenic solution heat exchanger, (16) ……
High temperature solution heat exchanger, (17), (20), (21), (22) …… tube, (24)
...... Overflow pipe, (25) …… pipe, (27) …… check valve,
(29) …… Overflow pipe, (C) …… Controller, (P) …… Pump, (S ₁ ) …… Liquid level detector, (S ₂ ), (S ₃ ), (S ₄ ) …… Temperature detector.

Claims (4)

[Claims] 1. A circulation path for a refrigerant and an absorption liquid is constructed by connecting equipment such as a high temperature generator, a low temperature generator, a condenser, an evaporator, an absorber, a high temperature solution heat exchanger, and a low temperature solution heat exchanger. And the flow path of the absorption liquid with the solution pump from the low temperature generator to the low temperature solution heat exchanger, the flow path of the absorption liquid from the low temperature solution heat exchanger to the absorber, and related to the reduction of the load. A double-effect absorption refrigerating machine, comprising: a controller that operates a solution pump when a changing physical quantity reaches a set value. 2. The double-effect absorption refrigerating machine according to claim 1, wherein the physical quantity is a temperature of an absorbing liquid which bypasses the high temperature solution heat exchanger from the high temperature generator and overflows to the low temperature generator. . 3. The double-effect absorption refrigerating machine according to claim 1, wherein the physical quantity is the temperature of the absorbing liquid which bypasses the low temperature solution heat exchanger from the low temperature generator and overflows to the absorber. 4. The double-effect absorption refrigerating machine according to claim 1, wherein the physical quantity is the liquid level of the absorbing liquid in the low temperature generator.