JP3208463B2 - 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 an absorption refrigerator using an aqueous solution of lithium bromide as an absorbing liquid and water as a refrigerant.
More particularly, the present invention relates to an absorption refrigerator having a function of preventing crystallization of an absorption liquid.

[0002]

2. Description of the Related Art Absorption refrigerators are operated at high temperatures and high concentrations in order to increase efficiency and obtain a good coefficient of performance. However, if the solution concentration rises above a predetermined level for some reason, the absorption liquid crystallizes, and the solution stops flowing, causing various problems such as locking of the absorption liquid pump and corrosion in the high-temperature regenerator.

For this reason, the concentration of the absorbent flowing into the absorber is calculated from the outlet temperature of the absorbent in the low-temperature regenerator and the refrigerant condensing temperature of the condenser, and when this concentration reaches a predetermined value (for example, 65%). The saving operation is performed by reducing the combustion amount of the high-temperature regenerator to, for example, 60%. If the concentration becomes less than a predetermined concentration (for example, 65%) after a predetermined time (for example, 10 minutes), the control returns to the normal control. There is an apparatus that performs control to determine that the regenerator has an abnormality when the concentration is equal to or higher than a predetermined concentration (65%) and to perform abnormal stop.

Further, the pressure of the low-temperature regenerator and the temperature of the absorbent having a high concentration from the low-temperature regenerator to the absorber are detected, the concentration of the absorbent is calculated, and the crystal concentration with respect to this pressure is calculated. A technique for obtaining a margin to a crystal has also been proposed.

[0005]

However, the method of determining the crystallization tendency of the absorbing solution by determining the concentration of the absorbing solution does not take the temperature of the absorbing solution flowing into the absorber into consideration, but merely measures the absorption solution. If the concentration exceeds the predetermined concentration, the amount of combustion is only reduced uniformly, so even if the cooling water temperature is high and the temperature of the absorbing solution is high, and there is no fear of actually crystallizing, There was a problem that the vehicle would enter a saving operation to prevent it. Further, in the technique of determining the crystallization tendency by obtaining the concentration of the absorbing solution, there is a problem that it is difficult to control with high accuracy because the amount of change in the concentration with respect to the temperature is small. It was an issue.

[0006]

According to the present invention, a regenerator, a condenser, an evaporator, an absorber, a low-temperature heat exchanger, a high-temperature heat exchanger, and the like are provided as specific means for solving the above-mentioned problems of the prior art. An absorption refrigerator configured by connecting pipes, wherein a temperature, a crystallization temperature, and a concentration of an absorbing solution flowing into an absorber are obtained,
When the temperature difference becomes equal to or less than a predetermined value and the concentration becomes equal to or more than a predetermined value, an alarm unit for outputting an alarm is provided. It is intended to solve the problems of the conventional technology.

[0007]

The crystallization temperature of the absorbent at this point is determined from the concentration on the inlet side of the absorber where the concentration of the absorbent is highest, and the crystallization temperature is compared with the temperature of the absorbent flowing into the absorber. The difference is equal to or less than a predetermined value, that is, it is confirmed that the actual absorption liquid approaches the temperature at which the absorption liquid starts to crystallize, and the concentration of the absorption liquid on the inflow side of the absorber is equal to or higher than a predetermined value. At this time, since the alarm is issued from the alarm means, the reliability of the alarm is high and the safety is high.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows that the refrigerant is, for example, water and an absorbing liquid (solution).
FIG. 1 is a schematic configuration diagram of an absorption chiller / heater, which is an absorption refrigerator using a lithium bromide (LiBr) solution, wherein 1 is an evaporator,
2 is an absorber, 3 is an evaporator absorber body containing the evaporator 1 and the absorber 2, 4 is a high temperature regenerator heated by a high temperature heat source such as a gas burner 5, 6 is a low temperature regenerator, 7 is a condenser Reference numeral 8 denotes a low-temperature regenerator condenser body containing a low-temperature regenerator 6 and a condenser 7, 9 denotes a low-concentration absorbent (hereinafter referred to as a dilute solution) flowing from the absorber 2 to the high-temperature regenerator 4, and a low-temperature regenerator. A low-temperature heat exchanger, which is a solution heat exchanger for exchanging heat with a highly concentrated absorbing liquid (hereinafter referred to as a concentrated liquid) flowing from the absorber 6 to the absorber 2, and a high-temperature heat exchanger 10 through the low-temperature heat exchanger 9 from the absorber 2. High-temperature heat exchangers 11 to 11, which are solution heat exchangers for exchanging heat between a dilute solution flowing in the regenerator 4 and an absorbing solution of intermediate concentration (hereinafter referred to as an intermediate solution) flowing from the high-temperature regenerator 4 to the low-temperature regenerator 6 Fifteen
Is an absorption liquid pipe, 16 is an absorption liquid pump, 17 and 18 are refrigerant pipes, 19 to 23 are refrigerant circulation pipes, 24 is a refrigerant pump, 25 is a refrigerant tank, and 26 is an evaporator heat exchanger 2 in the middle.
7 is a cooling water pipe in which an absorber heat exchanger 29 and a condenser heat exchanger 30 are provided in the middle.
Reference numeral 1 denotes a gas pipe connected to the gas burner 5, and 32 denotes a heating amount control valve, each of which is connected to the pipe as shown in FIG.

Reference numeral 33 denotes a refrigerant bypass pipe for connecting the refrigerant reservoir 34 of the evaporator 1 to the absorbent reservoir 35 of the absorber 2, reference numeral 36 denotes an on-off valve, and reference numeral 37 denotes a connection between the absorbent reservoir 12 and the absorber 2. Is an on-off valve, 38 is an on-off valve, 39 is a refrigerant vapor bypass tube connecting the refrigerant pipe 17 and the absorber 2, and 40 is an on-off valve, and each of the on-off valves 36, 38, and 40 is closed when cold water is supplied. , Open when hot water is supplied.

In step S 1, the heat exchange in the low-temperature heat exchanger 9 is completed, and the temperature T of the concentrated liquid flowing into the absorber 2 through the absorbing liquid pipe 15.
1 is a temperature detector for detecting the temperature of the temperature sensor 1. S2 is a concentration detector for detecting the concentration D of the concentrated liquid flowing out from the low-temperature regenerator 6 into the absorbent pipe 14, and the concentration detector is constituted by a sensor such as an ultrasonic wave.

Reference numeral 41 denotes an abnormality detecting device which receives a signal from each of the above-mentioned detectors, determines a crystallization tendency of the absorbing solution, and outputs a required signal to an alarm device 42 and a heating amount control valve 32. The detection device is provided, for example, on a control panel (not shown) of the absorption chiller / heater, and is configured by a microcomputer. An alarm device 42 is provided on the control panel similarly to the abnormality detection device 41, and operates by inputting a signal from the abnormality detection device 41. The alarm device 42 includes, for example, a display device 43 having a plurality of segment elements (not shown) and a buzzer 44. Display device 43
Is based on a signal from the abnormality detection device 41, for example, AL
Flashes the word ARM.

Hereinafter, the configuration of the abnormality detecting device 41 will be described with reference to FIG. An input interface 45 receives signals from the detectors S1 and S2, converts the signals, and outputs the converted signals to a central processing unit (hereinafter referred to as a CPU) 46. A storage device 47 stores a predetermined arithmetic program and the like (hereinafter referred to as a CPU). A ROM 48) is an output interface for inputting a signal from the CPU 46 and outputting a required signal to the alarm device 42 and the heating amount control valve 32, and 49 is a signal generator (hereinafter referred to as CLOCK) for outputting a signal every predetermined time. ),
Reference numeral 50 denotes a readable / erasable storage device (hereinafter referred to as a RAM) for storing the temperature and the concentration of the concentrated liquid detected by each detector.

[0013] the ROM47, the arithmetic expression for obtaining the crystallization temperature T _CR of the concentrated liquid from the concentration D of concentrated liquid concentration detector S2 is detected is stored. Specifically, the solubility curve of the aqueous LiBr solution shown in FIG. 3 (LiBr in the absorbing solution crystallizes at a temperature lower than the curve) is stored in the ROM 47, and the concentration detector S2 detects the concentration D of the concentrated solution. Then, the temperature T at which LiBr in the absorbing solution is crystallized is shown in FIG.
_CR is required.

Furthermore, the crystallization temperature was determined to do so in the ROM 47 T _CR and the arithmetic expression temperature detector S1 is compared with the concentrated solution temperature T1 for detecting, concentrated solution concentration D concentration detector S2 detects a calculation formula to be compared with the predetermined concentration D _C determined in advance the reference value for the temperature and concentration compared, for example, the first
Predetermined temperature 15 ° C., second predetermined temperature 10 ° C., first predetermined concentration D1: 65%, second predetermined concentration D2: 64, 5%
And an alarm device 42 and a heating amount control valve 3 when necessary.
2, a control program for outputting a required signal.

During the chilled water supply operation of the absorption chiller / heater of the above construction, the high temperature regenerator 4 is operated similarly to the conventional absorption chiller.
The refrigerant evaporated in the above flows through the low-temperature regenerator 6 to the condenser 7,
After condensing by exchanging heat with the cooling water flowing through the condenser heat exchanger 30, the refrigerant flows to the evaporator 1 via the refrigerant pipe 18.

The refrigerant exchanges heat with the water flowing through the evaporator heat exchanger 27 to evaporate, and the water flowing through the evaporator heat exchanger 27 is cooled by the heat of vaporization and circulated to the load. Also,
The refrigerant evaporated in the evaporator 1 is absorbed by the absorbing liquid in the absorber 2.

The diluted liquid having a reduced concentration after absorbing the refrigerant is sent to the high-temperature regenerator 4 through the low-temperature heat exchanger 9 and the high-temperature heat exchanger 10 by the operation of the absorption liquid pump 16. The diluted liquid sent to the high-temperature regenerator 4 is heated by the burner 5 to evaporate the refrigerant, and the intermediate liquid thus produced is converted into the high-temperature heat exchanger 1.
It flows to the low-temperature regenerator 6 through 0.

In the low-temperature regenerator 6, the intermediate liquid is supplied to the high-temperature regenerator 1
The refrigerant is heated by the refrigerant vapor flowing through the refrigerant pipe 17 from 0, and the refrigerant vapor is further separated to have a high concentration. It falls and is sent to the absorber 2 and is sprayed.

A part of the refrigerant liquid discharged from the refrigerant pump 24 enters the refrigerant tank 25 via the refrigerant circulation pipe 19. Then, a part of the refrigerant liquid that has passed through the weir in the refrigerant tank passes through the refrigerant circulation pipe 22 and fills the U seal portion of the refrigerant pipe 18, and the other flows into the evaporator 1 through the refrigerant circulation pipe 23.

The detection of an abnormality when the absorption chiller / heater is operated as described above will be described below.

The temperature T1 and the concentration D of the concentrated liquid detected by the temperature detector S1 and the concentration detector S2 are input to the input interface 4
5 and is temporarily stored in the RAM 50 via the CPU 46.

Then, based on the signal from the CLOCK 49, the concentrated liquid temperature T1 and the concentrated liquid concentration D stored in the RAM 50 are read into the CPU 46 at predetermined time intervals, and the crystallization temperature T is stored on the basis of the concentrated liquid concentration D. An arithmetic expression for calculating the _CR , an arithmetic expression for comparing the crystallization temperature _TCR with the concentrated solution concentration T1, an arithmetic expression for comparing the concentrated solution concentration D with a predetermined concentration Dc, a reference value for comparison, program for outputting appropriate required control signal is read from the ROM 47, the crystallization temperature _{T CR} at CPU 46, the temperature difference ΔT
(= T1− _TCR ) is sequentially calculated, and
The concentrations are compared.

For example, the concentrated liquid temperature T1 and the crystallization temperature _TCR
Temperature difference ΔT (= T1− _TCR ) from the first predetermined temperature 1
Higher than 5 ° C. and the concentration D of the concentrated liquid is the first predetermined concentration D
1, that is, if it is higher than 65%, a signal indicating that there is a slight abnormality is output from the CPU 46 to the alarm device 42 and the heating amount control valve 32 via the output interface 48, and the alarm device 4
In 2, the word ALARM blinks on the display device 43, and the opening of the heating amount control valve 32 is reduced to a predetermined opening, for example, 60%, so that the evaporation amount of the refrigerant is suppressed and the concentration of the absorbing liquid does not increase. Is started as described above.

Further, it concentrated liquid temperature T1 and the temperature difference ΔT between the crystallization temperature _{T CR (= T1-T CR} ) is, for example, be between the 10 ° C. first 15 ℃ and second predetermined temperature in a predetermined temperature ,
When the concentration D of the concentrated liquid is higher than the second predetermined concentration D2, that is, 64.5%, it is determined that the absorption liquid (LiBr) is highly likely to crystallize, and a signal indicating the occurrence of an abnormality is sent from the CPU 46 via the output interface 48 to the CPU 46. An alarm is output to the alarm device 42 and the heating amount control valve 32, and A is displayed on the display device 43 of the alarm device 42.
LARM flashes and buzzer 44 sounds,
In the heating amount control valve 32, the opening is set to zero to stop the fuel supply, and the operation of the absorption chiller / heater is abnormally stopped.

Since the present invention is not limited to the above-described embodiment, various modifications can be made without departing from the spirit of the appended claims.

[0026] For example, the temperature difference ΔT between the concentrated liquid temperature T1 temperature detector S1 is detected and the crystallization temperature T _CR divided into two regions, it may simply be controlled as a normal / abnormal.

Further, instead of the concentration D of the concentrated liquid detected by the concentration detector S2, the temperature T3 of the concentrated liquid detected by the temperature detector S3 indicated by a broken line provided in the absorbent pipe 14 and the refrigerant pipe 18
It is also possible to calculate and calculate the concentrated liquid concentration D based on the refrigerant liquid temperature T4 detected by the temperature detector S4 indicated by the broken line provided in FIG.

That is, the intermediate liquid flowing from the high-temperature regenerator 4 to the low-temperature regenerator 6 is heated by the refrigerant vapor flowing from the high-temperature regenerator 4 to the condenser 7 via the refrigerant pipe 17 to evaporate and separate the refrigerant. The concentration D of the concentrated liquid flowing through the absorbent pipe 14 is higher as the concentrated liquid temperature T3 detected by the temperature detector S3 is higher. It does not change even if the temperature is lowered by heat exchange with the dilute solution.

When the refrigerant liquid temperature T4 detected by the temperature detector S4 decreases due to, for example, a decrease in the temperature of the cooling water flowing through the cooling water pipe 28, the vapor pressure of the refrigerant in the condenser 7 decreases, and low-temperature regeneration is performed. The evaporation of the refrigerant in the vessel 6 becomes active, and the concentration D of the concentrated liquid flowing out to the absorbent pipe 14 increases.

Accordingly, the low-temperature regenerator 6 passes through the absorbent pipe 14, the low-temperature heat exchanger 9, and the absorbent pipe 15, and
The concentration D of the concentrated liquid flowing into the tank is determined by the concentrated liquid temperature T3 detected by the temperature detector S3 and the refrigerant liquid temperature T detected by the temperature detector S4.
4 can be written as D = F (T3, T4). If an experimental formula is obtained at a factory or the like for each model and rating of the absorption chiller / heater, the concentration of the concentrated liquid during operation can be calculated. Since D can be calculated based on the concentrated liquid temperature T3 and the refrigerant liquid temperature T4, the concentrated liquid concentration D obtained in this way can be used instead of the concentrated liquid concentration D detected by the concentration detector S2. It is.

[0031]

As described above, the present invention provides a regenerator
An absorption refrigerating machine constructed by connecting condensers, evaporators, absorbers, low-temperature heat exchangers, high-temperature heat exchangers, etc., with the temperature, crystallization temperature, and concentration of the absorbent flowing into the absorber. It is an absorption refrigerator equipped with alarm means for outputting an alarm when the temperature difference is equal to or less than a predetermined value and the concentration is equal to or more than a predetermined value.

Even when the concentration of the absorbing solution is high, if the absorbing solution temperature is high, it is determined that the absorbing solution does not crystallize, and a normal operation is performed. Since the temperature of the absorbing solution and the crystallization temperature of the absorbing solution at this portion approach each other, and an alarm is issued from the alarming means when the concentration becomes equal to or higher than a predetermined value, the certainty of the alarm is high and the safety is high. High in nature.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a device configuration according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating a configuration of an alarm unit according to the first embodiment.

FIG. 3 is an explanatory diagram showing a solubility curve of a LiBr aqueous solution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporator 2 Absorber 3 Evaporator absorber body 4 High temperature regenerator 5 Gas burner 6 Low temperature regenerator 7 Condenser 8 Low temperature regenerator condenser body 9 Low temperature heat exchanger 10 High temperature heat exchanger 11 ・ 12 ・ 13 ・ 14・ 15 Absorbent pipe 16 Absorbent pump 17 ・ 18 Refrigerant pipe 19 ・ 20 ・ 21 ・ 22 ・ 23 Refrigerant circulation pipe 24 Refrigerant pump 25 Refrigerant tank 26 Cold water pipe 27 Evaporator heat exchanger 28 Cooling water pipe 29 Absorber heat exchange Device 30 Condenser heat exchanger 31 Gas pipe 32 Heating amount control valve 33 Refrigerant bypass pipe 34 Refrigerant pool 35 Absorbent liquid reservoir 36 Open / close valve 37 Absorbent liquid bypass pipe 38 Open / close valve 39 Refrigerant vapor bypass pipe 40 Open / close valve 41 Abnormality detection device 42 Alarm device 43 Display device 44 Buzzer 45 Input interface 46 Central processing unit (CPU) 47 Storage device (ROM) 48 Output interface 49 signal generator (CLOCK) 50 memory (RAM) S1 · S3 · S4 temperature detector S2 concentration detector

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Eiichi Enomoto 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-2-40459 (JP, A) Hei 3-244973 (JP, A) JP-A-58-166073 (JP, A) JP-A-61-32586 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 15 / 00 306 F25B 49/04

Claims (1)

(57) [Claims] 1. An absorption refrigerator comprising a regenerator, a condenser, an evaporator, an absorber, a low-temperature heat exchanger, a high-temperature heat exchanger and the like connected by piping, wherein the absorption liquid flowing into the absorber is removed. A temperature, a crystallization temperature, and a concentration are obtained, and alarm means is provided for outputting an alarm when the temperature difference is equal to or less than a predetermined value and the concentration is equal to or more than a predetermined value. Absorption refrigerator.