JPH0586541B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a multiple effect absorption refrigerator, and in particular, a multiple effect absorption refrigerator suitable for extracting cold water during cooling operation and hot water during heating operation from the same location. This invention relates to an absorption refrigerator.

[Background of the invention]

Conventionally, in multi-effect absorption chillers that can perform heating and cooling in a single unit, such as a gas direct-fired cold/hot water unit, cold water during cooling operation is taken out from the cold water pipe that passes through the evaporator, but during heating operation There are three main methods for extracting hot water:

1. A method of installing a special water heater separately and extracting hot water from it.

2. A method of extracting hot water from a water pipe that passes through an evaporator.

3. A method of switching the cooling water system during cooling operation of the condenser and absorber.

(Japanese Utility Model Publication No. 53-54458) Of these methods, the method for extracting hot water from the evaporator is
They are becoming more and more popular because they do not require switching water systems between summer and winter.

However, the solution temperature during the heating cycle is often higher than with other methods, and in order to prevent this, it is necessary to adjust the amount of refrigerant in the sealed refrigerant in summer and winter. Also, due to solution temperature constraints, there was a problem in that the upper limit of the heating hot water outlet temperature had to be limited to 60°C or 65°C.

Another problem is that in order to lower the solution temperature during the heating cycle, a large refrigerant tank, which is unnecessary during cooling operation, must be attached.

Here, a conventional method of taking out hot water from an evaporator will be explained with reference to FIG.

FIG. 2 is a cycle system diagram showing a heating cycle of a conventional dual-effect absorption type water chiller/heater.

As shown in Figure 2, the main equipment of a dual-effect absorption type water chiller/heater is a plurality of regenerators consisting of a high temperature regenerator 1, a low temperature regenerator 2, an evaporator 3, an absorber 4, a condenser 5, and a heat regenerator. It consists of an exchanger 6, and these devices are connected by a piping system of refrigerant piping and solution piping as shown by solid line arrows in the figure.

In the cycle of this hot and cold water machine, a lithium bromide aqueous solution is used as the solution and water is used as the refrigerant.

The refrigerant piping system includes a refrigerant vapor pipe 9 that communicates from the high temperature regenerator 1 to the heating pipe group 2a of the low temperature regenerator 2;
A refrigerant vapor pipe 10 leading from the heating tube group 2a to the evaporator 3, and a refrigerant liquid pipe 1 connecting the evaporator 3 and the absorber 4.
1, 12 are piped, and refrigerant liquid pipes 11, 12
A refrigerant pump 7 is disposed between them.

The solution piping system includes dilute solution pipes 13, 14, and 15, which are the outward route from the absorber 4 to each regenerator, and concentrated solution pipes 1, which are the return route from each regenerator to the absorber 4.
6, 17, and 18 are piped. A solution pump 8 is installed in this solution piping system.

The refrigerant vapor generated by concentrating the solution by the external heat source 1a in the high-temperature regenerator 1 is superheated vapor with a temperature almost equal to the solution temperature in the high-temperature regenerator 1, so when it passes through the heating pipe 2a of the low-temperature regenerator 2, Next, a small amount of heat is applied to the solution outside the tube, turning it into saturated steam, and a small portion of it liquefies. Most of the steam passes through the refrigerant steam pipe 10 provided for heating operation and is directly delivered to the evaporator 3.
sent to. Here, heat is applied to the hot water flowing in the water pipe 19 to supply desired hot water, and the refrigerant itself becomes a refrigerant liquid, which is transferred to the absorber 4 side via the refrigerant liquid pipes 11 and 12 by the refrigerant pump 7. .

The dilute solution obtained by obtaining the refrigerant liquid is sent by the solution pump 8 to the high temperature regenerator 1 via the dilute solution pipes 13 and 14 and to the low temperature regenerator 2 via the dilute solution pipes 13 and 15. It is mainly separated into a concentrated solution and refrigerant vapor in the high-temperature regenerator 1.

The refrigerant vapor system is as described above, and on the other hand,
For concentrated solutions, from the high temperature regenerator 1 to the concentrated solution pipe 16,
It enters the heat exchanger 6 from the low-temperature regenerator 2 via the concentrated solution tube 17 and returns to the spray section 4a of the absorber 4 via the concentrated solution tube 18.

What determines the spray temperature at this time is the temperature of the concentrated solution returned from the high-temperature regenerator 1 and the low-temperature regenerator 2, and the performance of the heat exchanger 6, but going back further, it depends on the concentration of the solution throughout the cycle. However, it is extremely large.

That is, as the concentration of the solution in the absorber 4 increases during heating, the concentration after concentration in the high-temperature regenerator 1 and the low-temperature regenerator 2 also increases accordingly.

When the concentration becomes higher under the same pressure, the temperature becomes higher accordingly, and in this way, the concentration and temperature of the solution obtained from the high temperature regenerator 1 and the low temperature regenerator 2 will become higher and higher. I end up.

In addition, lithium bromide used as a solution is
It is generally highly corrosive to metals, but it exhibits particularly strong corrosivity when there is oxygen inside. Furthermore, if other conditions are the same, there is a problem in that the higher the temperature and concentration of the absorbing liquid, the more corrosive it becomes.

[Purpose of the invention]

The present invention was developed to solve the problems of the prior art described above, and in a heating operation cycle in which hot water is extracted from an evaporator, the present invention reduces the temperature of the solution in the absorber, thereby improving the overall cycle efficiency. The purpose of the present invention is to provide a multi-effect absorption refrigerating machine that can lower the temperature level, extend the life of the absorber components, and provide a stable heating operation cycle.

[Summary of the invention]

The structure of the multi-effect absorption refrigerator according to the present invention is as follows:
In a multi-effect absorption refrigerator consisting of an evaporator, an absorber, a condenser, a plurality of regenerators, a heat exchanger, and a piping system connecting these devices, a concentrated solution return piping from the plurality of regenerators to the absorber. A heat exchanger in which a branch part is provided in the middle of the system, one system path is led from the branch part to the spray part of the absorber, and the other system path is provided at the lower part of the evaporator to store the refrigerant. The absorber is connected to the solution reservoir of the absorber through a container, and these two systems are configured so that they can be switched during cooling and heating operations.

Additionally, the idea behind developing the present invention is as follows:
The following is true.

During heating operation of the multi-effect absorption refrigerator, when the concentration of the solution in the absorber increases, the concentration of the concentrated solution in each of the high-temperature and low-temperature regenerators increases and the temperature increases.

Generally, the absorber solution concentration during cooling operation is determined by the water temperature conditions of the cycle.

On the other hand, the absorber solution concentration during heating operation is determined by how much solution and how much refrigerant are mixed.

Theoretically, if the amount of refrigerant is increased without limit, the absorber spray temperature will gradually decrease, but in reality, it is not possible to increase the size of the refrigerant tank without limit, so the temperature will eventually match the hot water temperature. This means that the machine is being operated at an appropriate spray position.

By the way, if the temperature and concentration of the absorber spray during heating operation is high, the heat transfer tubes and structures exposed to it will be more likely to corrode in a short period of time, so it is very important to lower the absorber spray temperature. It turns out.

Therefore, in the present invention, the solution that is about to be sprayed onto the absorber tube group is guided to the heat exchanger installed at the bottom of the evaporator to cool it to below the saturated solution temperature inside the absorber. The idea was to prevent flashing from occurring when the solution is supplied to the solution, and to prevent direct exposure of the hot solution to heat exchanger tubes and structures.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a cycle system diagram showing a heating cycle of a dual-effect absorption type water chiller/heater according to an embodiment of the present invention. In the diagram, the same reference numerals as in FIG. Therefore, its explanation will be omitted.

In FIG. 1, 20 is a heat exchanger provided at the bottom of the evaporator 3, into which the refrigerant liquid guided from the refrigerant tray of the evaporator through the refrigerant liquid pipe 11a flows. , the refrigerant liquid pipe 11b, the refrigerant pump 7, and the refrigerant liquid pipe 12 to be sent to the absorber 4. 20a indicates a heat exchanger tube located within the heat exchanger 20.

Reference numeral 21 indicates a branch section provided in the middle of the concentrated solution return piping system leading from the plurality of regenerators to the absorber 4, and 22 indicates one of the lines from the branch section 21. After forming the heat transfer tube 20a in the heat exchanger 20, the solution reservoir 4b of the absorber 4
This concentrated solution tube 22 is equipped with a valve 23.

The other end from the branch part 21 becomes the concentrated solution pipe 18 and communicates with the spray part 4a of the absorber 4.
This concentrated solution tube 18 is equipped with a valve 24 .

Next, the operation of the piping system having such a configuration will be explained.

During heating operation, close valve 24 and close valve 23.
The concentrated solution is returned to the absorber 4 from the high-temperature regenerator 1 through the concentrated solution pipe 16 and from the low-temperature regenerator 2 through the concentrated solution pipe 17 through the heat exchanger 6, respectively.
It leads to the concentrated solution tube 22. The concentrated solution in the concentrated solution tube 22 evaporates the surrounding refrigerant by passing through the heat transfer tube 20a in the heat exchanger 20 provided at the bottom of the evaporation generator 3, and is cooled and absorbed by the latent heat of evaporation. The solution is returned to the solution reservoir 4b of the container 4.

During cooling operation, valve 23 is closed and valve 24 is closed.
It is opened to direct the concentrated solution from the regenerator, which returns to the absorber 4 via the heat exchanger 6 as described above, to the concentrated solution tube 18. The concentrated solution in the concentrated solution tube 18 is returned to the spray section 4a of the absorber 4 and is sprayed.

In this way, during cooling operation, the concentrated solution tube 1
8 to the spray 4a of the absorber 4, and during heating operation, the solution reservoir 4 of the absorber 4 via the concentrated solution pipe 22.
(b) These concentrated solution return piping systems can be switched by valve operation. During heating operation, even when the solution is directly returned to the solution reservoir 4b of the absorber 4, the heat exchanger 20 cools the solution below the saturation temperature, so boiling does not occur and the solution temperature in the absorber 4 decreases. Therefore, the temperature level of the entire cycle can be lowered, the life of the absorber components can be extended, and a stable heating operation cycle can be realized.

In the above-mentioned embodiment, an example of a dual-effect absorption type water chiller/heater was explained, but the present invention is not limited to this, and can be applied to a multi-effect absorption type chiller/heater for general use to the extent that similar effects can be expected. Needless to say, it can be applied to

〔Effect of the invention〕

As described above, according to the present invention, in a heating operation cycle in which hot water is extracted from an evaporator, the temperature level of the entire cycle is lowered by particularly reducing the temperature of the solution in the absorber, and the absorber configuration is It is possible to provide a multi-effect absorption refrigerating machine that can extend the life of materials and achieve a stable heating operation cycle.

[Brief explanation of the drawing]

FIG. 1 is a cycle system diagram showing the heating cycle of a dual-effect absorption type water chiller/heater according to an embodiment of the present invention, and FIG. 2 is a cycle diagram showing the heating cycle of a conventional dual-effect absorption type water chiller/heater. It is a cycle system diagram. 1...High temperature regenerator, 2...Low temperature regenerator, 3...
Evaporator, 4...Absorber, 4a...Spray part, 4
b...Solution reservoir, 5...Condenser, 6...Heat exchanger, 9, 10...Refrigerant vapor pipe, 11, 11a, 1
1b, 12... Refrigerant liquid pipe, 13, 14, 15...
Dilute solution tube, 16, 17, 18... Concentrated solution tube, 19
... Water tube, 20 ... Heat exchanger, 20a ... Heat exchanger tube, 21 ... Branch part, 22 ... Concentrated solution tube, 23,
24...Valve.

Claims (1)

[Claims] 1. In a multi-effect absorption refrigerator consisting of an evaporator, an absorber, a condenser, a plurality of regenerators, a heat exchanger, and a piping system connecting these devices, concentrated solution return from the plurality of regenerators to the absorber A branch part is provided in the middle of the piping system, and from the branch part, one line is led to the spray part of the absorber, and the other line is connected to the lower part of the evaporator to store the refrigerant. 1. A multi-effect absorption refrigerating machine, characterized in that it is connected to the solution reservoir of the absorber through an exchanger, and is configured such that both of these paths can be switched during cooling and heating operations.