JPS6316018B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in cooling water passage in an absorption refrigerator.

[Prior art]

Conventionally, in absorption refrigerators in which cooling water is passed through an absorber and a condenser in series, there are single-effect and double-effect absorption refrigeration systems in which cooling water is passed through an absorber and then a condenser. A dual-effect absorption refrigerator is known in which cooling water is passed through a condenser and then through an absorber.

These conventional examples will be explained based on the accompanying drawings.

FIG. 1 is a system diagram of an apparatus showing an example of a conventional single-effect absorption refrigerator. Further, FIG. 2 is a system diagram of an apparatus showing an example of a conventional dual-effect absorption refrigerator.

In Figure 1, 1 is an absorber, 2 is an evaporator, and 3
is a generator, 4 is a condenser, 5 is a solution pump, 6 is a refrigerant pump, 7 is a heat exchanger, 8 is a heat source calorie adjustment valve,
9 means a cooling water charging pump.

In FIG. 2, 1, 2, 4 to 6, 8 and 9 have the same meaning as in FIG. 1, 11 is the first generator, 12 is the second generator, 13 is the second heat exchanger, and 14 is the second heat exchanger. 1 is a heat exchanger, 15 is a flow control valve, 16 is a drain heat exchanger, and 17 is a drain trap.

The absorption liquid that has absorbed the refrigerant in absorber 1 and has become thin,
The solution is pressurized with a pump 5 and sent through a heat exchanger to a generator, where the refrigerant is separated and concentrated. The concentrated absorption liquid returns to the absorber, absorbs refrigerant, becomes thinner, and is pumped up again.

As mentioned above, there is also known a dual-effect absorption refrigerator shown in FIG. 2 in which the direction of cooling water is reversed (see Japanese Patent Publication No. 19668/1983).

However, these known absorption refrigerators have
There are problems described below.

First, in the absorption chiller shown in Figures 1 and 2, it is possible to shift the absorption solution concentration to the dilute solution side at maximum chilled water load, make maximum use of the absorption capacity, and keep it away from the crystal limit. can. However, on the other hand, at partial load or when the cooling water temperature is lower than the design temperature, excessive absorption capacity occurs and a large amount of refrigerant moves to the solution side, causing the evaporator refrigerant pump to drop due to the drop in the liquid level in the evaporator. There was a problem that cavitation phenomenon occurred and the driving cycle became extremely unstable.

On the other hand, if the cooling water flow direction is reversed, the temperature of the cooling water flowing into the absorber will be higher due to the cooling water that has been heated in the condenser and the temperature has risen, and at the maximum chilled water load, the absorption capacity will be lower than the above level. Since the concentration is smaller than in the case of , and the concentration shifts to the high concentration side, there is a risk of crystal precipitation. In particular, if the absorption capacity is reduced due to poor airtightness, most of the heat input is dissipated by the condenser, so high temperature cooling water constantly flows into the absorber.
In the dual-effect absorption refrigerator, the internal pressure of the first generator is relatively low, but the problem is that the solution concentration falls into the crystalline region.

These points will be explained in the attached FIG. 3. In other words, Figure 3 shows the absorption solution concentration (wt%) (horizontal axis)
It is a graph showing the relationship between and saturated vapor pressure (mmHg) (vertical axis).

However, in the conventionally known absorption refrigerator described above, the cycle point is the ABCD point or the ABCD point, depending on the state, and includes the above-mentioned problems.

[Purpose of the invention]

The present invention was made in order to solve the problems of the prior art described above, and its purpose is to enable continuous operation of the refrigerant pump even when there are load changes and cooling water temperature changes, so that cooling is always achieved. An object of the present invention is to provide an absorption refrigerator that can use water under optimal conditions.

[Structure of the invention]

To summarize the present invention, the present invention relates to an absorption refrigerator, and a refrigeration cycle is formed by an absorber, a generator, a condenser, an evaporator, a heat exchanger, and a solution path and a refrigerant path connecting them. , an absorption refrigerator in which cooling water is passed through the absorber and the condenser in series, a device for detecting a state quantity related to solution concentration fluctuation; It is characterized by being equipped with a flow path switching device that switches the direction of series water flow from the vessel to the condenser or from the condenser to the absorber.

In the present invention, examples of the state quantities related to the solution concentration fluctuation include the temperature of the solution in the absorber 1, the liquid temperature at the suction port of the solution pump 5, the cooling water temperature, the cold water temperature, and the temperature of the heat source heat amount adjustment valve 8. These include the degree of opening, the liquid level of the solution in the absorber 1, the liquid level of the refrigerant in the evaporator 2, and the density of the solution.

On the other hand, an example of the flow path switching device includes a cooling water pump 9
There is one or more switching valves connected to the outlet, for example a four-way valve or a plurality of two-way or three-way valves.

Next, the operation of the absorption refrigerator of the present invention will be explained.

When the load decreases or the cooling water temperature decreases during operation, the detection device is activated to switch the flow path, and the cooling water is passed from the condenser 4 and guided to the absorber 1. Therefore, the temperature of the cooling water passed through the absorber 1 increases, the absorption capacity decreases, and the concentration of the absorption solution increases. In this way, the liquid level of the refrigerant in the evaporator 2 is ensured, and the refrigerant pump 6 can be operated continuously without fear of cavitation.

On the other hand, when the load increases and the cooling water temperature rises, the detection device is activated and the flow path is switched.
Since the cooling water is first passed through the absorber 1, the concentration of the absorption solution can be kept relatively low, and a safe absorption cycle can be formed without fear of crystal precipitation.

That is, according to the present invention, in FIG.
Points a', b', c', and d' and points A', B', C', and D' are cycle points. Therefore, as mentioned above, in addition to ensuring the liquid level of the refrigerant in the evaporator 2, the range of change in concentration with respect to the entire load cycle is small and it moves away from the crystalline region, making it suitable for load fluctuations and cooling water temperature fluctuations. It is possible to obtain excellent responsiveness. In the example shown in FIG. 3, the explanation was given using a cycle diagram for a single effect cycle, but a similar concentration change is performed in a double effect cycle, and the same effect is obtained.

[Embodiments of the invention]

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 An example of the present invention is shown in FIG. In other words, FIG. 4 shows a case in which the present invention is applied to a single-effect absorption refrigerator.
FIG. 2 is a system diagram of an example device. In Figure 4,
Reference numerals 1 to 9 have the same meanings as in FIG. 1, 21 is a solution temperature detector in the absorber 1, 22 is a controller for the flow path switching device, 23 is a liquid temperature detector at the suction port of the solution pump 5, and 30 means a flow path switching four-way valve. 21
and 23 may be used.

When the load decreases or the cooling water temperature decreases during operation, the temperature of the solution in the absorber 1 decreases,
The detector 21 or 23 is activated to switch the flow path, and the cooling water is passed from the condenser 4 to the absorber 1. Thereby, as described above, the liquid level of the refrigerant in the evaporator 2 is ensured, and the refrigerant pump 6 can be operated continuously.

On the other hand, when the load increases and the cooling water temperature rises, the solution temperature in the absorber 1 increases, so the detector 21 or 23 is activated again, the flow path is switched, and the above-mentioned A safe absorption cycle is formed. The cycle diagram in this case is the points a', b', c', and d' in Figure 3, which have shifted to a higher concentration than the cycle points abcd in the conventional device, so the effects described above can be achieved. is played.

Although the specific case of single effect has been exemplified above, the present invention can also be applied to the case of double effect, or even if a detector or other type of switching valve is provided at another location as described above. it is obvious.

〔Effect of the invention〕

As explained in detail above, according to the present invention,
Cooling water can be used under optimal operating cycle conditions, and (a) excessive dilution of the solution is suppressed during partial loads and when the temperature of the cooling water drops, allowing continuous operation of the refrigerant pump.

(b) In connection with the above, the allowable cooling water inlet temperature will be lowered.

(c) Maximum absorption capacity can be used at maximum load;
It is possible to move it away from the crystalline region.

(d) In relation to (a) and (c) above, we were able to achieve the remarkable effects of small changes in solution concentration and quick response to load fluctuations.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an apparatus showing an example of a conventional single-effect absorption refrigerator, Fig. 2 is a system diagram of an apparatus showing an example of a conventional double-effect absorption refrigerator, and Fig. 4 is a system diagram of an apparatus showing an example of a conventional single-effect absorption refrigerator. FIG. 1 is a system diagram of an apparatus showing an example of applying the invention to a single-effect absorption refrigerator. FIG. 3 is a graph showing the relationship between absorption solution concentration and saturated vapor pressure in the prior art and the present invention. 1: Absorber, 2: Evaporator, 3: Generator, 4: Condenser, 5: Solution pump, 6: Refrigerant pump, 7: Heat exchanger, 8: Steam pressure control valve, 11: First generator, 12: Second generator, 13: Second heat exchanger, 1
4: first heat exchanger, 15: flow rate control valve, 21: solution temperature detector in absorber, 22: flow path switching device controller, 23: liquid temperature detector at suction port of solution pump, 30: Flow path switching 4-way valve.

Claims (1)

[Claims] 1. A refrigeration cycle is formed by an absorber, a generator, a condenser, an evaporator, a heat exchanger, a solution path and a refrigerant path connecting them, and cooling water is connected in series to the absorber and condenser. In an absorption refrigerating machine through which water is passed, a device for detecting a state quantity related to a solution concentration fluctuation, and a device for detecting a state quantity related to a solution concentration fluctuation, and a device for directing the cooling water from the absorber to the condenser or from the condenser to the absorber in accordance with the detected value. and a flow path switching device that switches the direction of water flow in series. 2. The absorption refrigerator according to claim 1, wherein the state quantity related to the solution concentration fluctuation is a liquid level in the evaporator or absorber. 3. The absorption refrigerator according to claim 1, wherein the state quantity related to the solution concentration fluctuation is the temperature of the cooling water. 4. The absorption refrigerator according to claim 1, wherein the state quantity related to the solution concentration fluctuation is the density of the solution or the temperature of the solution in the absorber. 5. The absorption refrigerator according to claim 1, wherein the flow path switching device is one or more switching valves connected to a cooling water pump discharge section.