JPS6113144B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid level control device for an absorption refrigerating machine, and in particular, the present invention relates to a liquid level control device for an absorption refrigerating machine. By changing the amount of liquid stored in the tank and automatically adjusting the concentration of the absorption liquid in response to fluctuations in cooling water temperature and cooling load, this system also prevents frequent starting and stopping of the refrigerant pump by ensuring continuous refrigerant circulation during pump operation. The purpose is to prevent

In general, various methods are available in which a refrigerant tank is attached to an absorption chiller and the concentration of the absorption liquid circulating in the refrigeration cycle is automatically adjusted according to the operating conditions of the chiller, such as fluctuations in cooling load and changes in cooling water temperature. However, conventional refrigerant tanks do not have a function to ensure that the liquid level in the refrigerant reservoir located on the suction side of the refrigerant pump exceeds a certain level.
If the refrigerant liquid level drops, the refrigerant pump may cavitate, causing pump failure.
Alternatively, when the refrigerant pump is stopped when the refrigerant liquid level falls below a certain level, the frequency of starting and stopping of the pump increases, making the pump more likely to malfunction.

The present invention, which was made in view of this point, will be explained below with reference to the drawings. 1 is a generator that heats a dilute absorption liquid that has absorbed a refrigerant with a heater 2 and separates it into the refrigerant and absorption liquid again; 3 is a generator that generates the A condenser 4 condenses and liquefies the refrigerant flowing from the condenser, and a condenser 5 distributes the liquid refrigerant from the condenser and uses latent heat when vaporizing it to obtain cold water for air conditioning. Evaporator, 6
9 is a refrigerant pump that supplies refrigerant to a sprayer 8 for spraying refrigerant to a water cooler 7 in the evaporator; 9 is a refrigerant pump that collects liquid refrigerant from the condenser 4 and unvaporized refrigerant sprayed in the evaporator 5; a refrigerant reservoir for replenishing the pump 6;
Reference numeral 10 denotes an absorber that keeps the inside of the evaporator 5 at a low pressure by dispersing the absorption liquid after the refrigerant is separated in the generator and absorbs the refrigerant vapor vaporized in the evaporator, thereby making it possible to continuously supply cold water. , 11 is a heat exchanger that exchanges heat between the concentrated absorption liquid flowing into the absorber 10 from the generator 1 and the dilute absorption liquid returned from the absorber 10 to the generator 1 by the absorption liquid pump 12,
These devices are airtightly connected through a refrigerant pipe 13, a dilute liquid pipe 14, a concentrated liquid pipe 15, etc., and constitute an absorption refrigerator.

This absorption refrigerator includes a first refrigerant tank 20 whose gas phase portion 16 is communicated with the condenser 4 and whose interior is divided into a liquid reservoir 18 and a liquid passage 19 by an overflow weir 17. and a second tank installed at a higher position than the refrigerant tank 20 and having the gas phase section 21 communicated with the evaporator 5.
A refrigerant tank 22 is attached, and the liquid reservoir 18 of the first refrigerant tank 20 and the bottom of the second refrigerant tank 22 are connected by a U-shaped pipe 23, and the liquid reservoir 18 and the discharge side 24 of the refrigerant pump 6 are connected. The liquid refrigerant passage 19 of the first refrigerant tank and the evaporator refrigerant reservoir 9 are connected via a pressure reducing device 25 such as an orifice, and a liquid refrigerant pipe 26.

Further, 27 is a check valve that prevents the liquid refrigerant from flowing down from the liquid reservoir of the first refrigerant tank, and the resistance R of the pressure reducing device 25 and the height h of the weir are determined when the absorption refrigerator is operated at 100% load. The pressure inside the evaporator at E
The relationship between the condenser pressure C and the pump discharge pressure P is determined based on a value that satisfies the relational expression h+H+R=E+P−C.

However, H refers to the bottom of the first refrigerant tank 20 and the refrigerant reservoir 9.
The equation is shown as a basic equation that does not take into account the check valve 27 or pipe resistance.

In the absorption refrigerant machine of the present invention having such a configuration, when the operation is stopped, the liquid level of the liquid reservoir 18 of the first refrigerant tank, the liquid level of the second refrigerant tank 21, The liquid level in the refrigerant reservoir 9 of the evaporator and the liquid level in the liquid refrigerant pipe 26 are at the same level.

Next, heating is started in the generator 1, cooling water is flowed into the condenser and absorber coolers 4 and 4', and the pumps 6 and 12 are started to start cooling operation.
A large amount of gaseous refrigerant is generated in the generator 1 and sent to the condenser 3.
As a result, the pressure in the condenser 3 increases, and the amount of liquid refrigerant also increases, gradually shifting to the refrigerant liquid level state as shown in FIG.

That is, FIG. 2 shows a state under a high cooling load, or when the cooling water temperature is higher than the designed temperature and the apparent load on the refrigerator is large, and the refrigerant liquefied in the condenser 3 is Due to the pressure difference between the condenser 3 and the evaporator 5, the liquid refrigerant flows through the liquid refrigerant pipe 26 into the liquid reservoir 9 of the evaporator, and this liquid refrigerant is sent to the spargeer 8 by the refrigerant pump 6 and vaporized. , while cooling the water cooler 7, some of the liquid refrigerant is stored in the second refrigerant tank 21 until it reaches the head difference h' that balances the pressure difference between the evaporator 5 and the condenser 3. The amount of refrigerant circulating inside is reduced, and the concentration of the absorption liquid is increased to provide cooling output that corresponds to high loads.

Next, when the cooling load decreases or the cooling water temperature decreases and the apparent cooling load decreases,
Since the amount of heating in the heater is reduced, when the absorption liquid concentration is the same as at the start of operation, there is a risk that the amount of refrigerant flowing into the condenser 3, and therefore the amount of liquid in the refrigerant reservoir 9 of the evaporator, will be depleted. In the invention, as the pressure in the condenser 3 decreases (the pressure also decreases in the absorber and evaporator, but the pressure decrease is not as large as in the condenser), the head difference h' decreases, and the pressure in the second refrigerant tank decreases. 2
The refrigerant stored in No. 1 passes through U-shaped pipe 23 to No. 1.
Since the refrigerant liquid is discharged into the liquid reservoir 18 of the refrigerant tank, the refrigerant liquid crosses the overflow weir 17 and flows into the evaporator 5 through the liquid refrigerant pipe 26. A part of the refrigerant liquid is mixed with the absorption liquid and is used in the absorption refrigeration cycle. The refrigerant is circulated through the refrigerant pump 6 and the liquid reservoir 18 of the first refrigerant tank to the refrigerant pipe 26 again. Therefore, it is possible to prevent the problem of cavitation in the refrigerant pump 6 due to depletion of the liquid amount in the liquid reservoir of the evaporator, as in the conventional case, and also to prevent excess liquid refrigerant from flowing into the first refrigerant.
Since the refrigerant is recirculated through the refrigerant tank, there is no need for a special device to detect the refrigerant liquid level and prevent cavitation of the refrigerant pump, and the refrigerant pump will continue to operate until some abnormality occurs and the protection device is activated. This can greatly reduce control equipment failure and pump wear and tear caused by frequent turning on and off of the refrigerant pump.

Furthermore, the absorption refrigerator having the device of the present invention gradually enters the state shown in FIG. 1 when the operation is stopped,
During this time, the refrigerant flowing into the evaporator from each pipe overflows and falls to the absorber side to dilute the absorption liquid, so the dilution time of the absorption liquid is shortened, and the absorption liquid pipe when continuous operation is stopped. In addition, since the check valve prevents the liquid refrigerant in the liquid reservoir from flowing down and a certain amount of liquid refrigerant is retained in the first refrigerant tank, it is possible to solve the problem of crystal formation when restarting operation. It also has the effect of accelerating the start-up of refrigeration performance.
Moreover, an absorption refrigerator having the device of the present invention is
Since the absorption liquid concentration is adjusted directly according to the pressure difference between the condenser and the absorber, it also exhibits the effect of excellent ability to follow concentration adjustment to changes in load and temperature of cooling water.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an absorption refrigerator having a liquid level control device according to the present invention, and FIG. 2 is a circuit diagram of the main parts similarly showing another operating state. 1... Generator, 3... Condenser, 5... Evaporator,
6...Refrigerant pump, 9...Refrigerant reservoir, 10...Absorber, 17...Overflow weir, 18...Liquid reservoir, 19...Liquid passage, 20...First refrigerant tank, 22...No. 2 refrigerant tank, 23... U-shaped pipe, 25... pressure reducing device,
26...Liquid refrigerant pipe.

Claims (1)

[Claims] 1. In an absorption refrigerator in which a generator, a condenser, a steamer, an absorber, a heat exchanger, etc. are sequentially connected via piping to form a refrigeration cycle, and chilled water for cooling can be supplied from the evaporator to the outside of the machine, the above-mentioned The refrigeration cycle includes a first refrigerant tank whose gas phase is communicated with the condenser and whose interior is divided into a liquid reservoir and a liquid passage by an overflow weir; A second refrigerant tank whose phase part is communicated with the evaporator is attached, and the liquid reservoir of the first refrigerant tank and the bottom of the second refrigerant tank are connected by a U-shaped pipe, and the liquid reservoir of the first refrigerant tank and the bottom part of the second refrigerant tank are connected. The discharge side of the refrigerant pump is connected through a pressure reducing device such as an orifice and a check valve, and the liquid passage of the first refrigerant tank and the refrigerant reservoir of the evaporator are connected through a liquid refrigerant pipe. Features: Liquid level control device for absorption refrigerators.