JP3186392B2 - 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 having an evaporator, an absorber, a generator, and a condenser as constituent components, mainly using water as a refrigerant and an aqueous solution of lithium bromide as an absorption solution. About.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6 and disclosed in Japanese Patent Application Laid-Open No. 2-213659, an evaporator A having a refrigerant liquid sprayer I, a refrigerant pump P, and a chilled water pipe W; A is provided in the same container U as A with an eliminator M interposed therebetween, and has a concentrated solution sprayer S and a cooling water pipe R and an absorber B.
Is connected to the absorber B via a solution pump G, a low-temperature heat exchanger L and a high-temperature heat exchanger H, and generates a refrigerant from a dilute solution containing a large amount of the refrigerant in the absorber B by heating by the heating source V. A generator C on the high-temperature side, and a heater K for flowing the refrigerant vapor generated by the generator C.
And a low-temperature generator D for generating a refrigerant from the intermediate-concentration solution after passing through the high-temperature heat exchanger H and a cooling water pipe R of the absorber B provided in the same vessel T as the low-temperature generator D
And a condenser E for condensing the refrigerant vapor generated in each of the generators C and D by a cooling water pipe J provided continuously in the subsequent stage. Thus, in the evaporator A, the cold water to be supplied to the cooling load to the cold water pipe W is taken out by the evaporation of the sprayed refrigerant.

In the above configuration, the generator C on the high temperature side is provided with a generator temperature detecting means X. The control unit F controls the detected generator temperature when an operation stop command is given. If the temperature is high, the dilution operation time is long, and if the detector temperature is low, the dilution operation time is short, and the heating source V of the high-temperature side generator C is controlled for a predetermined time until the operation is stopped. In a state where the heating amount is limited to zero by closing the valve N, the operation of the solution pump G, the refrigerant pump P, the chilled water pump Y, and the chilled water pump Z is continued, and the stop concentration control is performed after reducing the solution concentration in the machine. To prevent the generation of crystals in the machine.

[0004]

However, in the above, when the temperature of the generator C on the high temperature side is high, the solution concentration becomes high,
Since the solution concentration tends to be low when the temperature is low, the dilution operation time is extended when the detection generator temperature is high, and the dilution operation time is shortened when the detection generator temperature is low. Since the temperature changes depending on the temperature of the cooling water flowing through the cooling water pipe R of the absorber B, if the dilution operation time is determined based solely on the temperature of the high-temperature side generator C,
The dilution operation is not performed for a time that is not too short or short, and the dilution operation is stopped before the concentration decreases to the target concentration. After that, the dilution operation is continued unnecessarily, and there is a problem that is against energy saving.

[0005] In the present invention, by setting the dilution operation time in consideration of the cooling water temperature, the dilution operation is performed for a time that is not too short or too short, and the prevention of crystallization and energy saving can be effectively achieved. It is a main object of the present invention to provide a refrigerator.

[0006]

Therefore, in order to achieve the above-mentioned main object, according to the first aspect of the present invention, as shown in FIG. 1, an evaporator 1 for evaporating a refrigerant, and the evaporator 1 evaporates the refrigerant. An absorber 2 for absorbing the refrigerant into the solution, a generator 3 for generating the refrigerant from the solution in which the refrigerant has been absorbed by the absorber 2, and a condenser 5 for condensing the refrigerant generated by the generator 3 are provided. Is given, in an absorption refrigerator in which the operation is stopped after passing through a dilution operation in which the solution is circulated in a state in which the heating amount of the heating source 31 included in the generator 3 is limited,
Cooling water temperature detecting means 6 for detecting the temperature of the cooling water flowing through the cooling water pipe 23 connected to the absorber 2, generator temperature detecting means 7 for detecting the temperature of the generator 3, and when the operation stop command is given. When the detected cooling water temperature is low, the limit temperature of the generator 3 is lowered, and when the detected cooling water temperature is high, the limit temperature setting means 8 for setting the limit temperature high, and the temperature difference between the limit temperature and the detection generator temperature is determined. If smaller, increase the dilution operation time,
When the temperature difference is large, a dilution operation time setting means 9 for shortening the dilution operation time is provided.

According to a second aspect of the present invention, in order to determine the dilution operation time with higher accuracy in consideration of the temperature of the chilled water taken out from the evaporator 1, the evaporator 1 is used.
A chilled water temperature detecting means 14 for detecting a chilled water temperature taken out to a chilled water pipe 11 piped to a chilled water pipe 11; And a dilution operation time correction means 91 for compensating the dilution operation time to be longer with respect to the temperature difference determined by the dilution operation time setting means 9 as the detected cold water temperature is lower.

According to a third aspect of the present invention, the above main object is achieved by another configuration. As shown in FIG. 4, an evaporator 1 for evaporating a refrigerant, and a refrigerant evaporating in the evaporator 1 are provided. , A generator 3 for generating a refrigerant from the solution in which the refrigerant has been absorbed by the absorber 2, and a condenser 5 for condensing the refrigerant generated by the generator 3. In an absorption refrigerator in which the operation is stopped after a dilution operation in which the solution is circulated in a state where the amount of heating of the heating source 31 included in the generator 3 is limited,
Cooling water temperature detecting means 6 for detecting the temperature of the cooling water flowing through the cooling water pipe 23 connected to the absorber 2, generator temperature detecting means 7 for detecting the temperature of the generator 3, and when the operation stop command is given. When the detected cooling water temperature is low, the target lowered temperature of the generator 3 is lowered, and when the detected cooling water temperature is high, the target lowered temperature setting means 80 for setting the target lowered temperature high, and the detection generator temperature is lowered to the target lowered temperature. And a diluting operation continuation means 90 for continuing the diluting operation until the operation is completed.

[0009]

According to the first aspect of the present invention, the limit temperature setting means is provided.
Accordingly, when the detected coolant temperature when the operation stop command is given is low, the limit temperature of the generator 3 is low, and when the detected coolant temperature is high, the limit temperature is set high. This is because when the cooling water temperature is low, the temperature of the absorbing solution having the same concentration is lower than when the cooling water temperature is high, and the temperature at which crystals are generated is also lower. If the temperature difference between the limit temperature determined according to the cooling water temperature and the actual detection generator temperature is small, that is, if the actual generator temperature is close to the limit temperature, there is a risk that crystals will be generated. Is high, the dilution operation time is set long by the dilution operation time setting means 9, whereby the dilution operation can be performed only for a sufficient time, and the generation of crystals is sufficiently avoided. be able to. On the other hand, when the temperature difference between the limit temperature and the actual detection generator temperature is large, that is, when the actual generator temperature is much lower than the limit temperature, the risk of crystal formation is low, so dilution The operation time setting means 9 sets the dilution operation time to be short, thereby preventing unnecessary dilution operation from being performed unnecessarily and saving energy.

According to the second aspect of the present invention, the lower the detected chilled water temperature, the higher the limit temperature with respect to the detected chilled water temperature determined by the limit temperature setting means 8 by the limit temperature correction means 81, and the actual chilled water temperature is changed according to the chilled water temperature. The critical temperature, which serves as a reference for evaluating the generator temperature, is corrected. In addition to the correction of the limit temperature serving as the evaluation reference, the dilution operation time correction means 9
According to 1, the lower the detected chilled water temperature is, the longer the dilution operation time, which tends to be negative with respect to the temperature difference determined by the dilution operation time setting means 9, is corrected. By appropriately determining the amount of correction by the operation time correction means 91, it is possible to set an optimal dilution operation time in consideration of the cold water temperature, and to determine the dilution operation time with higher accuracy.

According to the third aspect of the present invention, when the target cooling temperature is low by the target lowering temperature setting means 80 when the operation stop command is given, the target lowering temperature of the generator 3 is low. When the water temperature is high, the target lowering temperature is set high. This is because, as described above, when the cooling water temperature is low, the temperature of the absorbing solution having the same concentration is lower than that when the cooling water temperature is high, and the temperature leading to crystal formation is lower, and the temperature of the generator 3 is lower. It is necessary to keep it. Then, the dilution operation is continued by the dilution operation continuation means 90 until the generator temperature decreases to the target decrease temperature determined according to the cooling water temperature, so that the dilution operation can be performed only for a sufficient time. In addition, the generation of crystals can be sufficiently avoided, and the unnecessary dilution operation can be prevented from being performed unnecessarily, and energy can be saved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment shown in FIG. 1 is a gas-fired double effect absorption refrigerator having a refrigerant liquid sprayer 12 and a refrigerant pump 13 for evaporating the refrigerant to form a cold water pipe. An evaporator 1 for taking out cold water to be supplied to the cooling load at 11 and an evaporator 1 provided adjacently to the evaporator 21 with an eliminator 21 interposed therebetween, a sparger 22 for a concentrated solution and a cooling water pipe 23, An absorber 2 for absorbing the refrigerant evaporated in the evaporator 1 into a solution; and a heating source 31 connected to the absorber 2 via a solution pump 60, a low-temperature heat exchanger 61 and a high-temperature heat exchanger 62 and comprising a burner 31a. A high-temperature side generator 3 for generating a refrigerant from a dilute solution that has absorbed a large amount of the refrigerant in the absorber 2, and a heater 41 for flowing the refrigerant vapor generated in the generator 3
And the high-temperature heat exchanger 6
And a low-temperature side generator 4 for generating a refrigerant from the intermediate-concentration solution after passing through the low-temperature side generator 4.
And a condenser 5 for condensing the refrigerant vapor generated in each of the generators 3 and 4 by a cooling water pipe 51 continuously provided at a stage subsequent to the cooling water pipe 23 of the absorber 2.

Burner 31 provided in high-temperature side generator 3
The heating amount of a can be changed by a heating amount control means 32 including a fuel supply valve 32a for controlling the fuel supplied to the burner 31a and its opening degree adjuster 32b. The opening of the fuel supply valve 32a is adjusted based on the outlet-side chilled water temperature Te detected by the chilled water temperature detecting means 14 provided in the above, so that the heating amount is increased or decreased according to the magnitude of the cooling load. .

When an operation stop command is given, the fuel control valve 32a is fully closed to limit the amount of heating by the burner 31a to zero.
And the refrigerant pump 13 and, although not shown, the operation of the chilled water pump interposed in the chilled water pipe 11 and the chilled water pump interposed in the chilled water pipe 23 were continued to perform a dilution operation for circulating the solution inside the machine. The operation is stopped later. Incidentally, 600 is a solution pump controller, and 130 is a refrigerant pump controller.

In the above configuration, a cooling water temperature detecting means 6 for detecting a cooling water temperature Tt flowing through the cooling water pipe 23 is provided at an inlet side of the cooling water pipe 23 connected to the absorber 2, and a generator on the high temperature side is provided. 3 is provided with a generator temperature detecting means 7 for detecting the temperature Tgh of the generator 3.

As shown in FIG. 2, when the detected cooling water temperature Tt when the operation stop command is given is low, the limit temperature Tm of the high-temperature side generator 3 is lowered, and the detected cooling water temperature Tt is reduced.
Is higher, a limit temperature setting means 8 for setting the limit temperature Tm higher is provided, and as shown in FIG. 3, a temperature difference ΔT = Tm−Tgh between the limit temperature Tm thus determined and the detection generator temperature Tgh. If the temperature difference is small, the dilution operation time is set to be long, and if the temperature difference ΔT is large, the dilution operation time setting means 9 is set to shorten the dilution operation time. The limit temperature setting means 8 and the dilution operation time setting means 9 are constructed by using a controller having a microcomputer.

Further, as shown in FIG. 2, the lower the detected chilled water temperature Te in the chilled water temperature detecting means 14 is, the lower the limit temperature Tm with respect to the detected cooling water temperature Tt determined by the limit temperature setting means 8 is. As shown in FIG. 3, a correction means 81 and a dilution operation time correction means 91 for correcting the dilution operation time for the temperature difference ΔT determined by the dilution operation time setting means 9 longer as the detected chilled water temperature Te is lower are provided. .

With the above arrangement, when the temperature difference ΔT = Tm−Tgh between the limit temperature Tm determined according to the cooling water temperature Tt and the actual detected generator temperature Tgh is small, that is, the actual generator temperature Tgh is When the temperature is close to Tm, there is a high risk that crystals will be generated. Therefore, the dilution operation time is set to be long, and the generation of crystals can be sufficiently avoided. When the temperature difference ΔT from the detection generator temperature Tgh is large, that is, when the actual generator temperature Tgh is much lower than the limit temperature Tm,
Since the risk of generation of crystals is in a low state, the dilution operation time is set short, and the dilution operation time can be shortened to save energy. In this control, the detected chilled water temperature Te is considered, and the chilled water temperature Te is considered.
The correction is performed by the limit temperature correction means 81 and the dilution operation time correction means 91 in accordance with the value of the temperature. Therefore, the optimum dilution operation time that also takes into account the cold water temperature Te can be determined, and the dilution operation can be performed with high accuracy. You can set the time.

FIG. 4 shows a second embodiment, which is different from the first embodiment of FIG. 1 in that when the detected cooling water temperature Tt when the operation stop command is given is low, the generator 3 on the high temperature side is used. As shown in FIG. 5, when the detected cooling water temperature Tt is high, the target lowering temperature Ts is set to be high, and the target generator temperature Tgh is set to the target lowering temperature Ts. That is, a dilution operation continuation unit 90 for continuing the dilution operation until the temperature is lowered is provided. Note that in FIG. 5, the target lowering temperature Ts is about 6
The temperature is about 5 to 10% lower than 5%, and the temperature is a solution concentration that does not generate crystals, that is, about 55 to 60%.

In the case of the second embodiment, the cooling water temperature Tt
Since the dilution operation is continued until the generator temperature Tgh decreases to the target reduction temperature Ts determined in accordance with the above, the dilution operation can be performed only for a sufficient amount of time, and the generation of crystals can be sufficiently avoided, and Energy can be saved.

It should be noted that the control for setting the limit temperature and determining the dilution operation time shown in the first embodiment and the control for setting the target lowering temperature and continuing the dilution operation shown in the second embodiment are used in combination. Alternatively, the dilution operation may be continued until the later one expires.

[0022]

As described above, according to the first aspect of the present invention, when the temperature difference between the limit temperature determined according to the detected cooling water temperature and the actual detection generator temperature is small, that is, the actual generator temperature is When the temperature is close to the temperature, the danger of crystal generation is high, so the dilution operation time is set longer,
Crystal generation can be sufficiently avoided, and conversely, if the temperature difference between the limit temperature and the actual detection generator temperature is large, that is, if the actual generator temperature is much lower than the limit temperature, crystals will be generated. The risk of doing so is low,
The dilution operation time is set short, and the dilution operation time can be shortened to save energy.

According to the second aspect of the present invention, in consideration of the detected chilled water temperature, correction is performed by the limit temperature correcting means 81 and the dilution operation time correcting means 91 in accordance with the value of the chilled water temperature. The optimum dilution operation time considering the cold water temperature can be determined, and the dilution operation time can be set with high accuracy.

According to the third aspect of the present invention, the dilution operation is continued until the generator temperature decreases to the target decrease temperature determined according to the detected cooling water temperature. It is possible to sufficiently avoid the generation of crystals, to prevent unnecessary dilution operation from being performed more than necessary, and to save energy.

[Brief description of the drawings]

FIG. 1 is a piping diagram showing a first embodiment of an absorption refrigerator according to the present invention.

FIG. 2 is an explanatory diagram of a limit temperature setting unit in the first embodiment.

FIG. 3 is an explanatory diagram of a dilution operation time setting means in the first embodiment.

FIG. 4 is a piping diagram showing the second embodiment.

FIG. 5 is an explanatory diagram of a target lowering temperature setting unit in the second embodiment.

FIG. 6 is a piping diagram of a conventional example.

[Explanation of symbols]

1; evaporator, 11; cold water pipe, 14; cold water temperature detecting means,
2; absorber 23; cooling water pipe 3; generator (high temperature side) 31; heating source 5; condenser 6; cooling water temperature detecting means 7; generator temperature detecting means 8; means,
81: limit temperature correction means, 9; dilution operation time setting means,
91: dilution operation time correction means, 80; target reduction temperature setting means, 90; dilution operation continuation means

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-213659 (JP, A) JP-A-3-67966 (JP, A) JP-A-61-101765 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) F25B 15/00 306

Claims (3)

(57) [Claims] An evaporator (1) for evaporating a refrigerant, an absorber (2) for absorbing the refrigerant evaporated in the evaporator (1) into a solution, and a refrigerant from the solution in which the refrigerant is absorbed by the absorber (2). And a condenser (5) for condensing the refrigerant generated in the generator (3), and a heating source (3) provided in the generator (3) when an operation stop command is given. 3
In an absorption refrigerator in which the operation is stopped after passing through a dilution operation of circulating the solution in a state in which the heating amount is limited in 1),
A cooling water temperature detecting means (6) for detecting a cooling water temperature flowing through a cooling water pipe (23) connected to the absorber (2); a generator temperature detecting means (7) for detecting a temperature of the generator (3);
A limit temperature setting means (8) for lowering the limit temperature of the generator (3) when the detected coolant temperature is low when the operation stop command is given, and increasing the limit temperature when the detected coolant temperature is high; A dilution operation time setting means (9) for setting a long dilution operation time when the temperature difference between the limit temperature and the detection generator temperature is small, and shortening the dilution operation time when the temperature difference is large. An absorption refrigerator. 2. A chilled water temperature detecting means (14) for detecting a chilled water temperature taken out to a chilled water pipe (11) connected to an evaporator (1).
A limit temperature correction means (81) for correcting the limit temperature with respect to the detected coolant temperature determined by the limit temperature setting means (8) to be higher as the detected chilled water temperature is lower; and a dilution operation time setting means (9) as the detected chilled water temperature is lower. The dilution operation time correction means (9) for compensating the dilution operation time for the temperature difference determined by
The absorption refrigerator according to claim 1, further comprising: (1). 3. An evaporator (1) for evaporating the refrigerant, an absorber (2) for absorbing the refrigerant evaporated in the evaporator (1) into a solution, and a refrigerant from the solution having absorbed the refrigerant in the absorber (2). And a condenser (5) for condensing the refrigerant generated in the generator (3), and a heating source (3) provided in the generator (3) when an operation stop command is given. 3
In an absorption refrigerator in which the operation is stopped after the dilution operation in which the solution is circulated in a state in which the heating amount is limited in 1),
A cooling water temperature detecting means (6) for detecting a cooling water temperature flowing through a cooling water pipe (23) connected to the absorber (2), a generator temperature detecting means (7) for detecting a temperature of the generator (3),
If the detected cooling water temperature when the operation stop command is given is low, the target lowered temperature of the generator (3) is lowered, and if the detected cooling water temperature is high, the target lowered temperature setting means ( 80) and a dilution operation continuation means (90) for continuing the dilution operation until the temperature of the detection generator decreases to the target reduction temperature.