JPH0217789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorption refrigerating machine that improves the starting characteristics at the start of operation and prevents absorbent carry over.

Small absorption chillers generally perform ON-OFF control as operation control according to the refrigeration load, and the circulation of absorption liquid and refrigerant also operates normally under conditions of a constant pressure difference between the devices. It has a flowing structure.

Therefore, at the start of refrigerator operation, when the temperature of the absorption liquid during the cycle of the absorption refrigerator is low and the pressure difference between each device has not reached a certain value, the absorption liquid does not flow down quickly, and the absorption There was a risk that the refrigerant would get mixed into the refrigerant circulation path (carry over).

Additionally, in the past, the circulation pump for the absorption liquid was stopped and the absorption liquid was heated in the generator until the absorption liquid reached a predetermined temperature. There is a risk that only the pressure in the vessel will rise abnormally, and for safety reasons, it is necessary to start operation of the absorption liquid pump at a temperature considerably lower than the normal temperature of the absorption liquid. With such a method, it is difficult to ensure a rapid rise in the temperature of the absorbing liquid and the pressure balance between each device, and therefore, even with such control, the starting characteristics at the start of operation are not good.

The present invention was developed in view of these points, and it is possible to control absorption liquid without using a large-scale control device used in large-scale absorption refrigerators, such as controlling the amount of heating in an absorption liquid pump, refrigerant pump, or generator. To provide an absorption refrigerating machine that uses a reversible pump as a circulation pump and can be used in small-sized absorption refrigerating machines at any time to control the amount of circulating fluid.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a high-temperature generator that heats a dilute absorption liquid using combustion gas such as gas or oil; 2 is the high-temperature generator; A separator 1 separates a gaseous refrigerant and an absorption liquid from the dilute absorption liquid that has been heated and ascended through a pumping pipe 3. A separator 4 uses the refrigerant vapor separated from the separator 3 as a heat source to further separate the intermediate absorption liquid. A low-temperature generator that heats and separates the refrigerant, 5 a condenser that cools and condenses the refrigerant flowing in from the generators 1 and 4 with a cooler 6, and 7 that collects latent heat when the liquid refrigerant from the condenser 5 is dispersed and vaporized. 9 is a bubble pump that returns liquid refrigerant that has not been vaporized in the evaporator 7 to the evaporator 7; 10 is a generator 1; In step 4, the concentrated absorption liquid from which the refrigerant has been separated is dispersed to absorb the refrigerant vapor inside the vessel, thereby maintaining the inside of the evaporator 7 at a low pressure and making it possible to continuously supply cold water. The container 11 has an on-off valve 12, and when the on-off valve 12 is opened during heating, the high temperature refrigerant from the separator 2 is guided to the evaporation absorption shell 13 together with the absorption liquid, so that hot water is removed from the heat exchanger 8 during heating. 14 is a reversible absorption liquid pump that returns to the generator 1 the diluted absorption liquid that is sprayed in the absorber 10 during heating and cooling.
15 and 16 are heat exchangers that exchange heat between the low temperature absorption liquid returning from the absorber 10 to the generator 1 and the concentrated absorption liquid flowing down from the generator 1 to the absorber 10; Absorption liquid pipes 19, 20, 21,
The pumping liquid pipe 3 and the bypass pipe 11 are connected to form an airtight circulation cycle of the refrigerant and the absorption liquid.

As shown in the performance curve of the absorption liquid pump 14 used in the absorption refrigerator of the present invention, for example, as shown in FIG. For example, as shown in Figure 3, when the liquid circulation volume is 100% in the normal energized forward rotation, the pump head is reversely energized and the pump head is reversely energized.
The liquid circulation amount is set at 60%.

Further, 22 and 23 are a high temperature thermostat and a low temperature thermostat for detecting the liquid temperature of the absorption liquid, and 24 is a controller that switches and controls the absorption liquid pump 14 between forward and reverse directions based on input from these thermostats.

FIG. 2 shows an example of the electric circuit of the controller 24 used in the absorption refrigerator of the present invention, in which 25 is a three-phase power supply, 14' is an electric motor for driving an absorption liquid pump, 26 is a normal energization switch contact, and 27 is the switch contact for reverse energization, 26' is the solenoid for the positive contact 26, 2
7' is the solenoid for the reverse contact 27, 28 and 28' are the first timer and its contacts, 29 and 29' are the second timer and its contacts, and 30 and 30' are the auxiliary relay and its normally closed contacts. be.

To explain the circuit operation in this embodiment, when the absorption refrigerator starts operating, the temperature of the absorption liquid is low, so the high temperature thermostat 22 is open, the low temperature thermostat 23 is closed, and the auxiliary relay 30' is not energized. Since the auxiliary contact 30 is closed, first, the first timer 28' starts operating, and after a certain period of time, the first timer 28 closing solenoid 27' is energized to close the reverse energization switch contact 27. The absorption liquid pump 14 starts rotating in reverse.

In this way, heating of the absorption liquid in the generator 1 is continued while the amount of liquid circulation by the absorption liquid pump 14 is suppressed, and when the temperature of the absorption liquid rises, the high temperature thermostat 22 is closed and the auxiliary relay 30' is Since the auxiliary contact 30 is energized and opened, the solenoid 27' is no longer energized, and the switch contact 27
is opened, and the absorption liquid pump 14 is temporarily stopped.

In this way, after securing the time until the absorption liquid pump 14 completely stops using the second timer 29', the second timer 29' is activated, contacts 29 and 26 are closed, and the absorption liquid The pump 14 becomes operational, and as the temperature of the absorption liquid further increases, the absorption refrigerator shifts to steady operation, and the low temperature thermostat 23 is opened.

Conversely, when the absorption refrigerator is stopped, first the heating in the generator 1 is stopped, and then the high temperature thermostat 2 is stopped.
2 is opened and the low temperature thermostat 23 is closed,
In such a case, the first timer 28' ensures time for the absorption liquid pump 14 to completely stop rotating, and then reverses the pump 14 to start dilution operation of the concentrated absorption liquid during the absorption refrigerator cycle. It is also operated under low-speed pump operation.

Although the absorption liquid pump in the above description is a rotary pump, if the amount of liquid discharged can be changed by switching between forward and reverse directions of the contacts, a vibrating pump can also be used as a reversible pump.

As described above, in the absorption refrigerating machine of the present invention, a reversible pump is used, which has a different amount of liquid discharged during forward rotation and reverse rotation, and a reversible pump that discharges a smaller amount of liquid during reverse rotation than during forward rotation. When the machine starts operating, it rotates in reverse, and after the temperature of the absorption liquid rises to a certain level, it switches to forward rotation, so when the absorption chiller starts operating, the absorption liquid pump rotates in reverse and the discharge liquid The amount of absorption liquid is reduced, and the amount of absorption liquid circulated can be reduced without using the rotation speed control device of the absorption liquid pump used in large absorption chillers. It can be used at any time to control the amount of circulation. In addition, at the start of operation, the circulation amount of the absorption liquid is reduced, and the temperature rise, concentration, and liquid flow of the absorption liquid are faster and approach a steady state, which shortens the time from the start of operation of the refrigerator to steady operation. In addition, it is possible to prevent absorption liquid from carrying over from the gas-liquid separator to the refrigerant circuit at the start of operation of the absorption refrigerator, which occurs in conventional absorption refrigerators.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an absorption refrigerating machine according to the present invention, FIG. 2 is an electric circuit diagram showing an example of controlling an absorption liquid pump, and FIG. 3 is a performance curve diagram of a reversible absorption liquid pump. 1~generator, 5~condenser, 7~evaporator, 10~
absorber, 14 - absorption liquid pump, 24 - controller.

Claims (1)

[Claims] 1. In an absorption refrigerator in which a generator, condenser, evaporator, absorber, etc. are connected by pipes to form a closed circulation cycle of refrigerant and absorption liquid, the pump that circulates the absorption liquid is used to rotate forward and backward. A reversible pump is used, which has a different amount of liquid discharged depending on the time, and when rotating in reverse, the amount of liquid discharged is smaller than when rotating forward, and the pump is controlled so that when the absorption chiller starts operating, it rotates in reverse, and the amount of absorption liquid decreases. An absorption refrigerator characterized in that the rotation can be switched to normal rotation after the temperature has risen to a certain level.