JP3227531B2 - Cooling operation method of absorption refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an absorption refrigerator for cooling operation in winter or the like when the temperature of cooling water decreases.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing the structure of a conventional absorption refrigerator of this type. As shown, the absorption refrigerator includes an evaporator 1, an absorber 2, a regenerator 3, a condenser 4, and a cooling tower 23. The regenerator 3 and the absorber 2 are connected by a solution pipe 12, and the absorber 2 and the regenerator 3 are connected by a solution pipe 11 via a solution pump 10. The regenerator 3 and the condenser 4 are connected by a refrigerant pipe 13, and the condenser 4 and the evaporator 1 are connected by the refrigerant pipe 1.
4, the evaporator 1 and the absorber 2 are connected by a refrigerant pipe 17 to form an absorption cycle.

[0003] The absorber 2, condenser 4 and cooling tower 23 are connected by a cooling water pipe 6, and a cooling water pump 5 circulates cooling water to the cooling tower 23. Reference numeral 7 denotes a refrigerant pump for circulating the refrigerant in the evaporator 1, and reference numeral 8 denotes a heating valve for controlling a heat flow rate of heat input to the regenerator 3 through the heating pipe 9. 21 is a chilled water pump and a chilled water pipe 2
0 circulates cold water between the load side (air conditioner 24) and the evaporator 1. Reference numeral 19 denotes a control device which receives the output of the cold water temperature sensor 18 and controls the heating valve 8 and the refrigerant pump 7.

In the above-described absorption refrigerator of the conventional construction, in the cooling operation, if the cooling water inlet temperature is started at a low temperature of, for example, 15 ° C. or less, the absorption solution concentration is low and the solution temperature is excessively lowered. 2, the absorption capacity was excessive.

[0005]

As described above, in the absorption refrigerator having the refrigerant pump 7 for spraying the refrigerant to the evaporator 1 side because the absorption capacity becomes excessive, the refrigerant liquid on the evaporator 1 side absorbs the refrigerant liquid. 2 is excessively absorbed, causing a shortage of the refrigerant liquid, causing a pump failure during cavitation operation of the pump, and an excessively high refrigeration capacity. If the load of the chilled water is small, a freezing accident due to a sharp drop in the chilled water temperature occurs. was there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and controls the amount of circulating water of a cooling water pump to a set temperature in accordance with a deviation between a set control temperature and an actual cooling water outlet temperature. An object of the present invention is to provide a cooling operation method of an absorption refrigerator capable of performing a stable cooling operation even when the temperature of the cooling water is excessively lowered in winter or the like.

[0007]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 comprises a regenerator, an absorber, an evaporator,
A cooling water pipe connecting the condenser, the condenser, and the cooling tower is formed while having a condenser, a solution passage connecting the liquid passage and a refrigerant passage, and a cooling water pump. A refrigerant pump for circulating refrigerant in the evaporator, a heating valve for controlling the amount of heat input to the regenerator,
In a cooling operation method of an absorption refrigerator including a control device for controlling a cooling water circulation amount by controlling a cooling water pump provided in a cooling / heating water pipe communicating an evaporator and a load side,
A cooling water inlet / outlet temperature sensor for detecting the cooling water condenser outlet temperature and the absorber inlet temperature is provided, and when the cooling water absorber inlet temperature is low at the time of starting the absorption refrigerator, the operation of the refrigerant pump is delayed, It is characterized in that the circulating water amount of the cooling water passing through the cooling water pipe is controlled so as to reach the set temperature in accordance with a deviation between the set control temperature and the actual cooling water outlet temperature.

According to a second aspect of the present invention, in the cooling operation method of the absorption chiller according to the first aspect, the circulation amount control of the cooling water is performed by a flow rate control valve provided in the cooling water pipe. Features.

According to a third aspect of the present invention, in the cooling operation method of the absorption refrigerator according to the first aspect, the cooling water circulation amount is controlled by controlling the rotation speed of the cooling water pump. .

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of an absorption refrigerator that performs a cooling operation method according to the present invention. In the figure, the portions denoted by the same reference numerals as those in FIG. 3 indicate the same or corresponding portions. The absorption refrigerator includes an evaporator 1, an absorber 2, a regenerator 3, and a condenser 4, and these are connected to a solution pipe 11,
2 and the refrigerant pipes 13, 14, 17 to form an absorption cycle.

The cooling water is circulated by the cooling water pump 5 through the cooling water pipe 6 to the absorber 2, the condenser 4, and the cooling tower 23. Further, a refrigerant pump 7 for circulating the refrigerant of the evaporator 1, a heating valve 8 for controlling the amount of heat of the regenerator 3, and a chilled water pump 2 provided in the chilled water pipe 20 on the load side.
1, a cooling water outlet temperature sensor 15 for detecting a cooling water outlet temperature, a cooling water inlet temperature sensor 25 for detecting a cooling water inlet temperature, a cooling water flow rate control valve 16 receiving an output signal thereof, and a cooling The cooling operation method of the present invention is implemented by providing the cooling water flow control device 22 for controlling the water pump.

FIG. 2 is a diagram showing a flow of an operation method according to the present invention. The cooling operation of the absorption chiller starts the chilled water pump 21 (Step ST2) and then starts the chilled water pump 5 (Step ST3) according to an operation command (Step ST1). After the start of the chilled water pump 5, the cooling water flow rate control device 22 detects a preset temperature and a cooling water outlet temperature sensor 15 provided at a cooling water outlet (a cooling water outlet of the condenser 4). From the deviation from the cooling water outlet temperature,
The inverter (not shown) of the cooling water pump 5 or the cooling water flow control valve 16 is controlled so that the cooling water outlet temperature becomes the set temperature (for example, 30 ° C.). The cooling water flow rate is controlled by controlling the opening of the flow rate control valve 16 (steps ST4 and ST5).

Subsequently, the combustion of a heating source, such as a combustor, for supplying a heating fluid to the regenerator 3 through the heating valve 8 and the heating pipe 9 is started (step ST6). Subsequently, it is determined whether or not the cooling water outlet temperature is equal to or higher than a set temperature (for example, 15 ° C.) (step ST7). If the temperature is equal to or higher than the set temperature, the refrigerant pump 7 is operated (normal operation) (step ST8). ,
If the temperature is equal to or lower than the set temperature, the operation of the refrigerant pump 7 is stopped (step ST9).

For example, in step ST4 of FIG.
If the cooling water outlet temperature at the time of startup is 10 ° C., the cooling water flow rate is controlled to the minimum flow rate allowed by the cooling water pump 5 to operate. When the cooling water outlet temperature is equal to or lower than the set temperature as in steps ST8 and ST9, the refrigerant pump 7
Do not drive. For this reason, the cavitation operation of the refrigerant pump 7 due to the shortage of the refrigerant liquid at the time of starting the evaporator 1 can be avoided. Further, since the cooling water flow rate is controlled based on the degree of deviation from the set temperature, excessive absorption capacity generation of the absorber 2 can be prevented, and the danger of freezing of the refrigerant and cold water on the evaporator 1 side can be avoided.

The amount of heating heat in the regenerator 3 is used not only for the load but also for concentrating the absorbing solution and radiating heat to the cooling water. As a result, the amount of refrigerant in the evaporator 1 gradually increases due to concentration, and the temperature of the cooling water system also rises due to heat radiation to the cooling water. The cooling water inlet temperature is a predetermined temperature (15 in this example).
℃), the suction liquid level of the refrigerant pump 7 becomes the allowable N
PSH or more, and the refrigerant pump 7 can be operated without cavitation. The opening of the heating valve 8 is controlled so that the cooling water flow rate is inversely proportional to the difference between the cooling water set temperature (30 ° C. in this example) and the temperature of the cooling water outlet temperature sensor 15,
When the cooling water outlet temperature reaches the set temperature, the cooling water flow rate becomes the maximum, and normal operation is performed.

The control of the cooling water flow rate is performed within an allowable range of the cooling water pump 5, and may be performed by a cooling water flow control valve 16 provided in the cooling water circulation system, or by controlling the pump rotation speed. In addition, the starting condition of the refrigerant pump 7 is set at the predetermined temperature of the cooling water in the above-described example.
May be provided with a level sensor at the liquid level below (the liquid suction part of the refrigerant pump), and at this level, the pump is started upon sensing an allowable NPSH or more.

Since the proper value of the control temperature of the cooling water differs depending on the operating cycle concentration characteristics, the amount of the absorbing solution and the amount of the refrigerant, the value of this embodiment is set as an initial value according to the actual operating environment. More stable control operation is possible.

[0018]

As described above, according to the present invention, when the temperature of the inlet of the cooling water is low when the absorption chiller is started, the operation of the refrigerant pump is delayed so that the cooling water passing through the cooling water pipe is cooled. Is controlled so as to reach the set temperature in accordance with the deviation between the set control temperature and the actual cooling water outlet temperature, so that the winter cooling operation is performed in the absorption refrigerator having a refrigerant pump for refrigerant spray on the evaporator side. In this case, the refrigerant liquid on the evaporator side is excessively absorbed by the absorber, causing a shortage of liquid and causing a failure of the pump due to cavitation operation of the pump or a freezing accident caused by a sudden decrease in chilled water temperature due to excessive refrigeration capacity. Thus, even when the temperature of the cooling water is excessively lowered in winter or the like, an excellent effect that stable cooling operation can be performed is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of an absorption refrigerator according to the present invention.

FIG. 2 is a diagram showing a flow of an operation method according to the present invention.

FIG. 3 is a diagram showing a configuration example of a conventional absorption refrigerator.

[Explanation of symbols]

 Reference Signs List 1 evaporator 2 absorber 3 regenerator 4 condenser 5 cooling water pump 6 cooling water pipe 7 refrigerant pump 8 heating valve 9 heating pipe 10 solution pump 11 solution pipe 12 solution pipe 13 refrigerant pipe 14 refrigerant pipe 15 cooling water outlet temperature sensor 16 Cooling water flow control valve 17 Refrigerant piping 18 Cold water temperature sensor 19 Control device 20 Cold water piping 21 Cold water pump 22 Cooling water flow control device 23 Cooling tower 24 Air conditioner 25 Cooling water inlet temperature sensor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tetsuya Endo 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (56) References JP-A-8-159596 (JP, A) JP-A Sho 60-16272 (JP, A) JP-A-4-217757 (JP, A) Japanese Utility Model Application Laid-Open No. 59-113175 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 15/00 306

Claims (3)

(57) [Claims] 1. A cooling system comprising a regenerator, an absorber, an evaporator, a condenser and a solution passage and a refrigerant passage communicating therewith to form an absorption cycle and connecting the absorber, the condenser and a cooling tower. It is configured to circulate cooling water with a cooling water pump having a water pipe, a refrigerant pump for circulating refrigerant of the evaporator, a heating valve for controlling the amount of heat input to the regenerator, the evaporator and A cooling operation method for an absorption refrigerator including a chilled water pump provided in a chilled / hot water pipe connecting a load side, and a control device for controlling the chilled water pump to control a circulating amount of the chilled water. A cooling water inlet / outlet temperature sensor for detecting the temperature and the absorber inlet temperature is provided, and when the cooling water absorber inlet temperature is low at the time of starting the absorption refrigerator, the operation of the refrigerant pump is delayed,
An operation method of an absorption refrigerator, wherein the amount of circulating water of cooling water passing through the cooling water pipe is controlled so as to reach a set temperature in accordance with a deviation between a set control temperature and an actual cooling water outlet temperature. 2. The operation method according to claim 1, wherein the circulation amount of the cooling water is controlled by a water flow control valve provided in the cooling water pipe. 3. The operation method according to claim 1, wherein the circulation amount control of the cooling water is performed by controlling a rotation speed of the cooling water pump.