JPS6115991B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improved performance in absorption cooling devices.

Conventionally, as a generator for an absorption cooling device, when a once-through type was used, in which the concentrated solution was forcibly circulated inside a heat exchanger such as a finch tube and heated by an external heat source, In order to improve the purity of the refrigerant vapor and recover sensible heat, a method is used in which a part of the concentrated solution is separated and the separated concentrated solution is brought into contact with the refrigerant vapor directly or indirectly, or in a combination of both. . FIG. 1 shows an example of this type of once-through generator. Arrows 1, 4, 6, and 7 indicate the flow directions of the main concentrated solution, branched concentrated solution, diluted refrigerant solution, and refrigerant vapor, respectively. The main concentrated solution flowing from the direction 1 receives heat from the combustion gas such as LNG burned by the gas burner 8 in the finch tube 2, boils and evaporates, and enters the gas-liquid separator 3, where the refrigerant vapor and dilute solution are Separated by difference in specific gravity. The refrigerant vapor rises between the packings 5 such as Raschig rings, flows in from the direction of the arrow 4, and comes into countercurrent contact with the branched concentrated solution descending between the packings 5,
After exchanging substances and heat, the liquid is discharged in the direction of arrow 7, that is, toward the condenser. The branched concentrated solution after contact with the refrigerant vapor is mixed with the dilute solution accumulated at the bottom of the gas-liquid separator 3, and then discharged in the direction of arrow 6, that is, toward the absorber. The solution that is dispensed is called the final dilute solution). The temperature and concentration of the final dilute solution are determined by the temperature, concentration, and amount of the branched concentrated solution to be mixed, but in general, the concentration of the branched concentrated solution is higher than the concentration of the diluted solution before being mixed, and the temperature is also diluted. Since it is lower than the solution temperature, the concentration of the final dilute solution will be higher and the temperature will also be lower. In order to improve the performance of an absorption chiller with such a generator, the concentration and temperature of the final dilute solution should be as close as possible to the original dilute solution state before it is mixed with the branched concentrated solution. Preferably close. Otherwise, an increase in entropy will occur and the efficiency of the device will decrease. In addition, when using a fluorocarbon-based refrigerant, a device with good performance at as low a temperature as possible is desired in terms of heat resistance, but with conventional cooling devices, it is necessary to The dilute solution temperature must be higher than the final dilute solution temperature, which shortens the life of the solution.

The present invention aims to improve these conventional problems.

To achieve this objective, the present invention provides a refrigerant-enriched solution ( A branched concentrated solution (hereinafter referred to as branched concentrated solution) is made to flow into the refrigerant vapor passage from the gas-liquid separator provided at the outlet of the generator to the condenser without heating. Sensible heat is absorbed from the refrigerant vapor, and the branched concentrated solution that has absorbed the sensible heat is heated in the generator to release the refrigerant vapor and mixed with the dilute solution in which the refrigerant concentration has decreased, and then is returned to the absorber. A heat exchanger is provided for heating the branched concentrated solution that has undergone heat exchange and mass exchange (rectification) with the refrigerant vapor in the reflux passage using an external heat source.

The details of the present invention will be described in FIGS. 2 and 3 of the drawings below.
This will be explained with figures. FIG. 2 shows an embodiment according to the present invention. FIG. 2 shows an embodiment in which the heat of combustion gas is used as a method of externally heating the branched concentrated solution to bring it into contact with refrigerant vapor and then raise the temperature of the main diluted solution to the temperature of the main diluted solution. arrow 9,1
4, 15, 16, and 19 indicate the flow directions of the branch concentrated solution and the final dilute solution after contact with the main concentrated solution, branched concentrated solution, refrigerant vapor, and refrigerant gas, respectively. The main concentrated solution coming in from arrow 9 is Finch Yube 10
Heat is obtained from the gas burned in the burner 20, which boils and generates refrigerant vapor, which becomes a gas-liquid two-phase flow that enters the gas-liquid separator 11 and is separated into the main dilute solution and refrigerant vapor due to the difference in specific gravity. They. As the refrigerant vapor rises in the filling tank 13, it comes into direct contact with the branched concentrated solution falling from above, exchanging heat and substances, lowering the temperature and increasing the purity at the same time, and moving in the direction of the arrow 15, that is, toward the condenser. It is then discharged. On the other hand, the branched concentrated solution accumulates in the solution reservoir 12 after coming into contact with the refrigerant vapor, and is indicated by the arrow 16.
to the heat exchanger 17. The heat exchanger 17 is connected to a drum 18 wrapped around the burner 20, and absorbs the heat of the combustion gas, boils it, and generates refrigerant vapor. The mixture of refrigerant vapor and branch dilute solution is raised by the bubble pump and enters the gas-liquid separator 11, where it is separated into refrigerant vapor and branch dilute solution. The branch dilute solution is mixed with the main dilute solution to form the final dilute solution. The branch dilute solution is brought to match the temperature and concentration of the main dilute solution by appropriately changing the size of the heat exchanger 17. As a result, the temperatures of the final dilute solution, main dilute solution, and branch dilute solution are the same, and there is no reduction in efficiency due to mixing as in the prior art.

FIG. 3 shows an estimated value of the rate of improvement in efficiency compared to the conventional example described above. The horizontal axis represents a dimensionless number obtained by dividing the weight of the branched concentrated solution by the weight of the refrigerant, and the efficiency improvement rate increases as this amount increases. This is because as the amount of branched concentrated solution increases, in the generator shown in the conventional example, the final diluted solution temperature becomes significantly lower than the main diluted solution temperature, resulting in a decrease in efficiency. In conventional methods, in order to purify refrigerant vapor and recover its sensible heat into a branched concentrated solution, the larger the amount of branched concentrated solution, the greater the effect, but on the other hand, the larger the amount of branched concentrated solution, the lower the final dilute solution temperature. The drop in temperature from the main dilute solution temperature was significant, hindering efficiency improvement by branching the concentrated solution. The present invention solves this problem by bringing the branched concentrated solution into contact with refrigerant vapor and then heating it with an external heat source, thereby achieving remarkable effects.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional generator for absorption type cooling equipment, Fig. 2 is a block diagram of a generator for absorption type cooling equipment according to an embodiment of the present invention, and Fig. 3 is a characteristic diagram showing efficiency improvement rate. It is. 2, 10... Finch tube, 3, 11... Gas-liquid separator, 17... Heat exchanger, 12... Solution reservoir,
18...Drums.

Claims (1)

[Claims] 1 A part of the solution containing a large amount of refrigerant (hereinafter referred to as concentrated solution) sent from the absorber to the generator of an absorption cooling device having at least a generator, a condenser, an evaporator, an absorber, and a solution pump is branched. A concentrated solution (hereinafter referred to as a branched concentrated solution) is caused to flow into the refrigerant vapor passage from the gas-liquid separator provided at the outlet of the generator to the condenser without being heated, absorb sensible heat from the refrigerant vapor, and remove the sensible heat from the refrigerant vapor. A reflux passage is provided in which the branched concentrated solution that has absorbed heat is heated in the generator, releases refrigerant vapor, and is mixed with a dilute solution with a reduced refrigerant concentration, and then refluxed to the absorber. Heat and mass exchange with refrigerant vapor (rectification)
A generator for absorption cooling equipment equipped with a heat exchanger that heats the branched concentrated solution using an external heat source.