JP2858931B2 - Control device for absorption refrigerator - Google Patents

Description

The present invention relates to an absorption refrigerator, and more particularly to a control device for an absorption refrigerator equipped with a generator heated by a heat source fluid.

(B) Prior art For example, in Japanese Patent Application Laid-Open No. 61-62762, a high-temperature generator, a low-temperature generator, a condenser, an evaporator, and an absorber are connected to each other by pipes to form a refrigeration cycle and evaporate. An absorption chiller / heater for extracting cold water from a water heater and extracting hot water from a water heater attached to a high temperature generator is disclosed. The absorption chiller / heater is provided with a mechanism for reducing the flow rate of the cooling water supplied to the inside of the absorption chiller when the chilled water is partially loaded.

(C) Problems to be Solved by the Invention In the above conventional technology, for example, when the high-temperature generator uses a heat source fluid such as engine cooling water from a gas engine as a heating source, when there is a limit in the supply capacity of the heat source fluid,
The regeneration temperature of the generator drops. For this reason, before the temperature rises to the temperature required for refrigerant regeneration, heat is released to the cooling water system, and although heat is input from the heat source fluid, there is a problem that the refrigeration capacity cannot be exhibited according to the heat input. Was.

An object of the present invention is to stabilize the operation of an absorption refrigerator equipped with a generator using a heat source fluid as a heating source.

(D) Means for Solving the Problems In order to solve the above problems, the present invention uses a heat source fluid of a generator of an absorption refrigerator as cooling water or cooling steam of an engine, and separates the absorber and the condenser from each other. In the absorption refrigeration cycle in which the cooling water is circulated, the pipe that returns the heat source fluid from the generator to the engine side includes a three-way valve with a bypass pipe that bypasses the generator, and is provided downstream of the three-way valve. An object of the present invention is to provide a control device for an absorption refrigerator equipped with a mechanism for controlling the circulation amount of the cooling water so as to stabilize the temperature of the heat source fluid.

In addition, the amount of heating of the generator is controlled by controlling the opening of the three-way valve by the chilled water load in the evaporator of the absorption refrigerator, and the absorption refrigeration system is provided with a cooling water pump that circulates cooling water to the absorber and the condenser. In a cycle, there is provided a control device for an absorption refrigerator including a mechanism for controlling a rotation speed of the cooling water pump so as to stabilize a hot water outlet temperature by a temperature detector provided on a downstream side of the three-way valve. .

(E) Action In order to control the circulation amount of the cooling water so as to stabilize the temperature of the hot water downstream of the three-way valve, which is the reflux temperature of the hot water (heat source fluid) to the heating source, for example, the temperature of the hot water outlet has decreased. In such a case, the number of rotations of the cooling water pump (15) is reduced to reduce the circulation amount of the cooling water. As a result, the amount of heat transferred to the cooling water in the absorber (6) and the condenser (3) is reduced, and the generator (2)
, The operation of the absorption refrigerator can be stabilized.

In addition, moderately cooled hot water is recirculated to the gas engine, etc., which is the heating source, so that the entire combined system of the absorption refrigerator and the gas engine stabilizes not only at startup but also at steady operation. Can be changed.

(F) Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a single effect absorption refrigerator using an aqueous solution of lithium bromide (LiBr) as an absorbent (absorbing liquid) and using water as a refrigerant.

In FIG. 1, (1) is a generator condenser body containing a generator (2) and a condenser (3), and (4) is an evaporator (5).
And an evaporator / absorber body containing the absorber (6). The evaporative absorber body (4) and the generating condenser body (1) are composed of a rare absorbent pipe (8), a concentrated absorbent downflow pipe (9), and a refrigerant provided with an absorbent pump (7) on the way. Liquid down pipe (1
0) is connected by piping. (11) is a refrigerant circulation pipe connected to the evaporator (5), (12) is a refrigerant pump, and (13) is a cold water pipe. (14) is a cooling water pipe,
Reference numeral (15) denotes a cooling water pump, and a cooling water circulation path returning from the cooling tower (not shown) to the cooling tower via the absorber (6) and the condenser (3) by the cooling water pipe (14). Is formed. Further, (16) is a heat exchanger between the rare absorbing solution and the concentrated absorbing solution.

(17) is a hot water pipe connected to the generator (2), and the hot water pipe (17) is connected to, for example, a gas engine. Then, the cooling water of the gas engine (hereinafter referred to as hot water) circulates in the hot water pipe (17). (18) is a three-way control valve provided in the middle of the hot water pipe (17), and (20)
Is a bypass pipe bypassing the generator (2).

(21) is a chilled water outlet temperature detector, and (22) is a heating amount controller. The heating amount controller (22) receives a temperature signal from the chilled water outlet temperature detector (21) and outputs an opening signal to the three-way control valve (18) according to the temperature. Also, (23) is a hot water outlet temperature detector provided in the hot water pipe (17a) on the outlet side of the three-way control valve (18), (24) is a cooling water pump controller, (25)
Is an inverter device. Then, the cooling water pump controller (24) receives the temperature signal from the hot water outlet temperature detector (23) and outputs a frequency signal to the inverter device (25) according to the hot water outlet temperature. Here, the relationship between the hot water outlet temperature and the frequency is as shown in FIG. 2, for example, and the rated frequency of the cooling water pump (15) is 60 Hz.

Hereinafter, the operation of the absorption refrigerator configured as described above will be described.

During the operation of the absorption refrigerator, the absorption liquid pump (7), the refrigerant pump (12), and the cooling water pump (15) are operated as in the conventional absorption refrigerator, and the absorption liquid, the refrigerant, and the cooling water are absorbed. Circulate the refrigerator. Also, a hot water pipe (1
Hot water circulates through 7) and the generator (2) is heated. When the temperature detected by the chilled water outlet temperature detector (21) is higher than the set temperature, the opening degree of the three-way control valve (18) on the bypass pipe side is reduced by the opening signal from the heating amount controller (22). As a result, the valve opening on the generator side increases, and the amount of heating of the generator (2) increases. Also, when the chilled water outlet temperature is lower than the set temperature, the valve opening on the bypass pipe side of the three-way control valve (18) is increased by the signal from the heating amount controller (22), and the valve opening on the generator side is increased. Becomes smaller and the generator (2)
Decreases the amount of heating.

Also, when the absorption refrigerator is operated as described above,
For example, when the heat supply amount on the heat source side decreases, the temperature of the hot water flowing to the generator (2) decreases, and the temperature of the generator (2) decreases. Then, the temperature of the hot water returning from the generator (2) decreases. Then, the temperature of the hot water flowing out of the three-way control valve (18), that is, the hot water outlet temperature of the three-way control valve (18) decreases. As a result, the cooling water pump controller (24) drops the hot water outlet temperature input from the hot water outlet temperature detector (23),
The frequency signal output by operating the cooling water pump controller (24) decreases. Then, the frequency of the electric power supplied from the inverter device (25) to the cooling water pump (15) decreases,
The rotation speed of the cooling water pump (15) decreases. Then, the circulation amount of the cooling water discharged from the cooling water pump (15) decreases, the amount of heat transferred to the cooling water in the absorber (6) and the condenser (3) decreases, and the temperature of the generator (2) increases. I do.

When the temperature of the generator (2) rises and the amount of refrigerant vapor generated increases, the concentration of the absorbing liquid increases and the condenser (3)
The refrigerant liquid flowing from the evaporator (5) to the evaporator (5) evaporates, thereby exhibiting a refrigerating ability. When the temperature of the generator (2) rises, the temperature of the hot water outlet of the generator (2) rises, and the temperature of the hot water outlet of the three-way control valve (18) rises.

Also, when the absorption refrigerator is started, the rotation speed of the cooling water pump (15) is reduced based on the hot water outlet temperature of the three-way control valve (18) to keep the flow rate of the cooling water small. by this,
The temperature of the generator (2) rises quickly, and the refrigeration capacity is exhibited.

If the heat supply amount on the heat source side increases, the temperature of the hot water flowing through the generator (2) rises, and the hot water outlet temperature of the three-way control valve (18) rises, the cooling water pump controller (twenty four)
Output a larger frequency signal. For this reason, the rotation speed of the cooling water pump (15) increases, and the circulation amount of the cooling water increases. When the circulation amount of the cooling water increases, the amount of heat transferred to the cooling water in the absorber (6) and the condenser (3) increases, and the temperature of the generator (2) decreases. Then, the amount of refrigerant vapor generated in the generator (2) decreases, and the refrigeration capacity of the absorption refrigerator decreases. When the temperature of the generator (2) decreases, the hot water outlet temperature of the generator (2) decreases, and the hot water outlet temperature of the three-way control valve (18) decreases.

According to the above embodiment, the number of revolutions of the cooling water pump (15) is controlled according to the temperature of the three-way control valve (18) on the hot water outlet side,
If the temperature of the hot water outlet side of the three-way control valve (18) decreases due to an increase in the cold water load or a decrease in the amount of heat supplied to the heat source side of the hot water, the rotation of the cooling water pump (15) is performed based on the hot water outlet temperature. The temperature of the generator (2) can be stabilized at a high level by reducing the flow rate of the cooling water by reducing the flow rate of the cooling water and reducing the amount of heat transferred to the cooling water. And stable operation.

Also, when the absorption chiller is started, the rotation speed of the cooling water pump (15) is reduced based on the hot water outlet temperature to reduce the flow rate of the cooling water and reduce the amount of heat transferred to the cooling water. The temperature of (2) can be quickly raised, and the absorption refrigerator can be reliably started.

Furthermore, the hot water outlet temperature of the three-way control valve (18) can be stabilized, and the return temperature of the heat source, that is, the return temperature of the cooling water of the gas engine, can be prevented from dropping significantly. The operation of the entire system can be stabilized.

In the above embodiment, the amount of circulation of the cooling water to the absorber (6) and the condenser (3) was adjusted by controlling the rotation speed of the cooling water pump (15). The same operation and effect can be obtained when a control valve is provided in the controller and the opening degree of the control valve is controlled by the hot water outlet temperature of the generator (2).

Further, the heat source fluid is not limited to hot water, and even when the heat source fluid is, for example, steam from a gas engine,
By controlling the circulation amount of the cooling water based on the steam outlet temperature of the three-way control valve, it is possible to obtain the same operation and effect as the above embodiment.

(G) Effect of the Invention The present invention is a control device for an absorption refrigerator configured as follows, and stabilizes the temperature of a heat source fluid downstream of a three-way valve with a bypass pipe at the entrance and exit of a heat source fluid of a generator. A mechanism for controlling the amount of circulation of the cooling water between the absorber and the condenser, specifically, a mechanism for controlling the number of revolutions of the cooling water pump is provided. By reducing the amount of circulation of cooling water based on
The absorption refrigerator can be started quickly. In addition, when the temperature of the heat source fluid decreases, the amount of heat transferred from the absorber and condenser to the cooling water is reduced by reducing the amount of cooling water circulated, preventing the temperature of the generator from dropping excessively. In addition, the operation of the absorption chiller can be stably continued, and the cooling water of the heat source device such as a gas engine can be prevented from being excessively cooled due to a significant decrease in the heat source fluid return temperature. And the operation of the entire system combining the heat source equipment such as the gas engine can be stabilized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an absorption refrigerator showing one embodiment of the present invention, and FIG. 2 is a diagram showing a relationship between a temperature of a hot water outlet and a frequency. (2) ... generator, (3) ... condenser, (5) ... evaporator, (6) ... absorber, (15) ... cooling water pump, (1)
7) Hot water piping, (18) Three-way control valve, (20)
Bypass pipe, (23) ... Hot water outlet temperature detector, (24) ...
... cooling water pump controller.

Claims (2)

(57) [Claims] 1. A generator, a condenser, an evaporator, an absorber, etc., which use a heat source fluid such as cooling water or cooling steam of an engine as a heating source, are connected by piping, and the cooling water is circulated between the absorber and the condenser. In the absorption refrigeration cycle, the pipe for returning the heat source fluid from the generator to the engine side includes a three-way valve with a bypass pipe that bypasses the generator, and the heat source fluid temperature on the downstream side of the three-way valve is controlled. A control device for an absorption refrigerator comprising a mechanism for controlling a circulation amount of the cooling water so as to stabilize the cooling water. 2. A hot water pipe for connecting a generator, a condenser, an evaporator, an absorber, and the like, which uses a heating source such as engine cooling water as hot water, to return the hot water from the generator to the engine side, Equipped with a three-way valve with a bypass pipe that bypasses the vessel,
In the absorption refrigeration cycle including a cooling water pump that circulates cooling water through an absorber and a condenser while controlling the amount of heating of the generator by controlling the opening of a three-way valve by a chilled water load in the evaporator, A control device for an absorption refrigerator comprising a mechanism for controlling the rotation speed of the cooling water pump so as to stabilize the hot water outlet temperature by a temperature detector provided downstream of the valve.