JPS6223229B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-lithium salt absorption refrigerating machine, and more particularly to a water-lithium salt absorption refrigerating machine equipped with a control function to maintain the amount of refrigerant in the circulation system in an optimum state. Regarding.

First, a conventional water-lithium salt absorption refrigerator will be explained with reference to FIG.

In FIG. 1, reference numeral 1 denotes a high-temperature regenerator into which a dilute solution is introduced and heats it; 2 a separator that separates high-temperature steam heated and boiled in the high-temperature regenerator 1 from an intermediate concentrated solution; 3; is a low temperature regenerator,
The intermediate concentrated solution separated in the separator 2 is lowered in temperature by heat exchange with the dilute liquid in the high temperature heat exchanger 8, and then introduced and heated with high temperature steam from the separator 2. 4
is a condenser, into which the refrigerant vapor generated by heating the intermediate concentrated solution from the low-temperature regenerator 3 and the liquid refrigerant condensed by removing heat from the intermediate concentrated solution are introduced, and the cooling water flows through the cooling water coil 11. It is cooled and condensed by water. Reference numeral 5 denotes an evaporator, in which the refrigerant condensed in the condenser 4 is stored in a liquid receiving part 13 at the lower part, passes through a pipe 19, and is further spread over a cold water heat transfer coil 12 via a dispersion pipe 14, where it is evaporated. do.

Reference numeral 6 denotes an absorber, in which the concentrated solution from the low-temperature regenerator 3 is cooled down by the low-temperature heat exchanger 7 and then introduced and spread over the coil 11 to absorb the refrigerant vapor evaporated by the evaporator 5. , resulting in a dilute solution. Note that the absorbed heat generated at this time is removed by the cooling water flowing inside the coil 11. 9 is a solution circulation pump that sends the dilute solution to the high temperature regenerator 1 via heat exchangers 7 and 8; 10 is a cooling/heating switching valve for switching between air conditioning and cooling.

A refrigerant storage chamber 15 is maintained at the same pressure as the evaporator 5 by a communication pipe 20. A part of the refrigerant condensed in the condenser 4 is introduced into the refrigerant storage chamber 15 through a pipe 19 and is stored therein depending on the pressure difference between the condenser 4 and the evaporator 5. Refrigerant is stored in this refrigerant storage chamber 15 when the cooling water temperature is high and the pressure inside the condenser 4 is high, and when the pressure is low, the stored refrigerant is discharged to adjust the solution concentration in the system. I'm starting to do that.

However, in such a conventional refrigerator, the refrigerant storage chamber 15 has a structure in which the refrigerant is stored when the pressure in the condenser 4 is high, and the refrigerant is discharged when the pressure in the condenser 4 is low. Because it was old, it had the following drawbacks.

(1) For example, change the heat input of the refrigerator depending on the cooling load.
When performing High-Low control, the pressure in the condenser 4 decreases during Low operation, so the refrigerant storage chamber 1
5, the refrigerant flows out, lowering the solution concentration in the system and reducing the absorption capacity.

(2) When the operation is stopped, the refrigerant flows out as in 1, so it is necessary to store the refrigerant in the refrigerant storage chamber 15 when the operation is started, and if the ON-OFF operation is repeated that much, the efficiency will deteriorate. That is, efficiency during partial load operation deteriorates.

The present invention has been made with the object of eliminating such conventional drawbacks.

An embodiment of the water-lithium salt absorption refrigerator according to the present invention will be described in detail below with reference to FIGS. 2 to 4. Note that in FIG. 2, the same parts as in FIG. 1 are designated by the same reference numerals, so the explanation of those parts will be omitted.

FIG. 2 is a system diagram showing an embodiment of the present invention, which differs from the conventional system shown in FIG. 1 in the following points. That is, the lower part of the refrigerant storage chamber 15 and the liquid receiving part 13 at the lower part of the condenser 4 are directly connected by the pipe 22, and the upper part of the refrigerant storage chamber 15 and the evaporator are connected by the overflow pipe 21 instead of the communication pipe 20. 5 are in communication. This overflow pipe 21
When the refrigerant storage chamber 15 is full of refrigerant,
It functions to allow overflowing refrigerant to flow into the evaporator 5 and to maintain the pressure within the refrigerant storage chamber 15 at the same pressure as the internal pressure of the evaporator 5. Further, the bottom of the refrigerant storage chamber 15 is connected to the dispersion pipe 14 portion of the evaporator 5 via a pipe 19.
is provided with a control valve 16 whose opening degree is changed as appropriate. A temperature sensor 18 is attached to the evaporator 5 to detect the temperature of the evaporator 5, and a controller 17 is provided to process a signal from the temperature sensor 18 and instruct the valve opening degree of the control valve 16. It is being
The control valve 16 is controlled to close when the temperature of the evaporator 5 is high, and to open when the temperature of the evaporator 5 is low.

Next, the operation of the present invention configured as described above will be explained.

The refrigerant condensed in the condenser 4 is transferred to the condenser 4 because the overflow pipe 21 is connected to the evaporator 5.
The refrigerant is stored in the lower pressure refrigerant storage chamber 15 through the pipe 22 depending on the pressure difference and gravity. The stored refrigerant flows into the evaporator 5 through the pipe 19 by gravity, and is spread over the cold water heat transfer coil 12.
It removes heat from the cold water flowing through it and evaporates. By the way, when the temperature of the evaporator 5 decreases (for example, the cooling water temperature decreases), the valve opening of the control valve 16 widens and the amount of refrigerant flowing in increases. Therefore, the refrigerant liquid level in the refrigerant storage chamber 15 decreases. In the opposite case, for example, when the cooling water temperature is high, the opening degree of the control valve 16 is narrowed, the amount of refrigerant flowing in decreases, and the refrigerant liquid level rises. That is, depending on the temperature of the evaporator 5, the control valve 1
By proportionally changing the opening degree of the refrigerant storage chamber 15, the liquid head changes in accordance with the flow path resistance, so the liquid level position in the refrigerant storage chamber 15 can be set arbitrarily.
This adjusts the solution concentration within the system to a desired value.

Next, when the refrigerator operation is stopped, the evaporator 5
As the temperature increases, the control valve 16 closes. Therefore, the refrigerant in the refrigerant storage chamber 15 does not flow out. When the refrigerator starts operating, the control valve 16 opens when the temperature of the evaporator 5 decreases, and the evaporator 5
The refrigerant in the refrigerant storage chamber 15 flows into the refrigerant storage chamber 15 . Also evaporator 5
If the temperature of the refrigerant is high and the control valve 16 remains closed, the refrigerant in the refrigerant storage chamber 15 will be full, but as the refrigerant flows into the evaporator 5 through the overflow pipe 21, the concentration in the system will exceed a certain value. does not rise.

FIG. 3 shows an example of the relationship between the temperature of the evaporator 5 detected by the temperature sensor 18 and the valve opening degree of the control valve 16, which is fully open at 2°C and fully closed at 6°C.

FIG. 4 shows the relationship between the flow rate of refrigerant passing through the control valve 16 and the height of the refrigerant liquid level in the refrigerant storage chamber 15, using the valve opening degree of the control valve 16 (evaporator temperature) as a parameter.

The refrigerant flow rate of the control valve 16 is proportional to the amount of heat input. Therefore, during high heat input operation, the liquid level in the refrigerant storage chamber 15 takes a value indicated by the intersection with line a depending on the evaporator temperature. On the other hand, during low heat input operation, the refrigerant flow rate of the control valve 16 decreases, and at the same evaporator temperature, the refrigerant liquid level in the refrigerant storage chamber 15 decreases to a value indicated by the intersection with line b. However, if the control temperature range shown in Figure 3 is set appropriately, the concentration of the absorption solution decreases as the refrigerant liquid level decreases, and as the evaporator temperature increases, the valve opening changes in the direction of closing, so it is always set. The evaporator temperature is maintained at a constant temperature, and there is no generation of ineffective refrigerant.

As explained above, according to the present invention, the following effects can be obtained.

(1) Since the solution concentration in the system decreases as the cooling water temperature decreases, the temperature of the evaporator 5 does not drop excessively, and freezing of the refrigerant can be prevented even at low cooling water temperatures.

(2) When high-low heat input is controlled according to the cooling load, the refrigerant is stored in the refrigerant storage chamber 15 during low heat input operation, so the solution concentration will not drop too much and efficiency will not drop as in the past. .

(3) By controlling the evaporator temperature to always maintain a constant temperature, the amount of ineffective refrigerant caused by insufficient absorption capacity is reduced and efficiency is increased.

(4) By closing the control valve 16 when the operation is stopped, the refrigerant in the refrigerant storage chamber 15 does not flow out.
The overall efficiency increases during ON-OFF operation, that is, at low loads.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a conventional water-lithium salt absorption refrigerator, FIG. 2 is a system diagram showing an embodiment of the water-lithium salt absorption refrigerator according to the present invention, and FIG.
4 is a characteristic diagram showing the relationship between the opening degree of the control valve and the evaporator temperature, and FIG. 4 is a characteristic diagram showing the relationship between the liquid level height in the refrigerant storage chamber and the refrigerant flow rate using the evaporator temperature as a parameter. 1... High temperature regenerator, 2... Separator, 3... Low temperature regenerator, 4... Condenser, 5... Evaporator, 6... Absorber, 7...
Low-temperature heat exchanger, 8... High-temperature heat exchanger, 9... Solution circulation pump, 10... Cooling/heating switching valve, 11... Cooling water coil, 12... Cold/hot water coil, 13... Liquid receiving section, 14...
Dispersion pipe, 15... Refrigerant storage chamber, 16... Control valve, 17
... Controller, 18 ... Temperature sensor, 19 ... Pipe for passing refrigerant, 21 ... Refrigerant overflow pipe.

Claims (1)

[Claims] 1. A high-temperature regenerator that heats a dilute solution obtained by absorbing a refrigerant into a lithium salt solution, a separator that separates the refrigerant vapor from this high-temperature regenerator and an intermediate concentrated solution, and the intermediate concentrated solution separated by this separator. a low-temperature regenerator for heating with refrigerant vapor from the separator after lowering the temperature;
a condenser that condenses refrigerant from the low-temperature regenerator;
an evaporator that evaporates the liquid refrigerant condensed in the condenser; and an absorber that absorbs the refrigerant evaporated in the evaporator into the concentrated solution from the low-temperature regenerator;
In a water-lithium salt absorption refrigerator in which these components form a circulation system, there is a refrigerant storage chamber that is connected to the condenser and stores the refrigerant condensed in the condenser, and an upper part of the refrigerant storage chamber and the evaporator. a connecting pipe that connects the bottom of the refrigerant storage chamber and the evaporator via a control valve that can appropriately change the valve opening of the control valve; or a controller for controlling the temperature of the evaporator according to the temperature of the evaporator.