JPH06317361A - Absorption type refrigerator - Google Patents

Abstract

PURPOSE:To improve a regulating accuracy of coolant concentration irrespective of variations in an operating state, a coolant temperature, etc., by so regulating a flow rate of refrigerant liquid that a concentration of absorption liquid becomes a target value set in response to a temperature of the coolant. CONSTITUTION:Concentration calculating means 31 calculates a concentration of absorption liquid from a detected temperature of coolant temperature detecting means Sw and a detected temperature of absorption liquid temperature detecting means Sy based on correlation among the concentration, the temperature of the liquid, and a temperature of coolant. Since absorption capacity of the liquid is different according to the temperature of the coolant, it is necessary to regulate the concentration of the liquid to a suitable concentration responsive to the temperature of the coolant. Then, target concentration setting means 32 sets a suitable target concentration responsive to the detected temperature of the means Sw. Flowrate control means 33, 34 operate to bring the calculated concentration of the means 31 to the target concentration. Thus, a regulating accuracy of the concentration of the liquid can be improved irrespective of variations in an operating state, the temperature of the coolant, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporator for evaporating a refrigerant liquid, an absorber for absorbing a refrigerant vapor generated in the evaporator into an absorbing liquid, and a liquid pool communicating with the evaporator and the absorber. And a regenerator for regenerating an absorption liquid diluted with a refrigerant, the liquid pool portion, the regenerator and the absorber are connected by an absorption liquid circulation path, a condenser and the evaporator Relates to an absorption refrigerating machine connected by a refrigerant liquid supply passage having a flow rate adjusting means interposed therebetween.

[0002]

2. Description of the Related Art In such an absorption refrigerating machine, there is a risk that the absorbent may crystallize when the concentration of the absorbing liquid exceeds a proper range.
On the other hand, if it is lower than the proper range, the absorption capacity of the absorption liquid for absorbing the refrigerant vapor is lowered and the refrigeration capacity is lowered, so that the concentration of the absorption liquid needs to be maintained within the proper range. Conventionally, while providing a refrigerant liquid storage chamber for storing the refrigerant liquid in the condenser,
A level sensor or the like for detecting the amount of refrigerant liquid stored in the refrigerant liquid storage chamber is provided, and the concentration of the absorbing liquid is adjusted by controlling the flow rate adjusting means based on the detection information of the level sensor.

[0003]

However, in the above-mentioned conventional absorption refrigerator, the refrigerant liquid storage chamber and the level sensor must be provided, and the level sensor is provided with the detection section in the condenser and the detection information. Since it has to be provided in a state of being led out of the condenser, there is a problem that the configuration for adjusting the concentration of the absorbing liquid becomes complicated.

Incidentally, in order to solve the above-mentioned problems,
By providing a temperature sensor that detects the inflow temperature of the cooling water to the absorber that affects the absorption capacity of the absorbing liquid, and performing feedforward control of the flow rate adjusting means based on the detection information of the temperature sensor, the concentration of the absorbing liquid There is something to adjust.

However, due to fluctuations in operating conditions (adjustment of the amount of heat input for adjusting the regeneration capacity of the regenerator, adjustment of the circulation amount of the absorption liquid circulating in the absorption liquid circulation path, etc.), the condensation capacity of the condenser Since the regeneration capacity of the regenerator fluctuates, the amount of refrigerant liquid retained in the condenser fluctuates, that is, the amount of refrigerant liquid in the absorbing liquid circulating in the absorbing liquid circulation path changes. fluctuate. Therefore, in the feedforward control of the flow rate adjusting means based on the detection information of the temperature sensor, no measure is taken against the fluctuation of the refrigerant liquid retention amount in the condenser. As a result, the accuracy of adjusting the concentration of the absorbing liquid is poor due to the fluctuation of the refrigerant liquid retention amount, and the dispersion of the concentration of the absorbing liquid becomes large, so the operation becomes unstable, and improvement is desired.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the accuracy of adjusting the concentration of the absorbing liquid with a simple structure regardless of the change in the operating state.

[0007]

A first characteristic configuration of an absorption refrigerator according to the present invention is a cooling water temperature detecting means for detecting the temperature of cooling water flowing through the absorber and the condenser. An absorption liquid temperature detection means for detecting the temperature of the absorption liquid regenerated by the regenerator, and a concentration for calculating the concentration of the absorption liquid based on the detection information of the cooling water temperature detection means and the absorption liquid temperature detection means A calculation means and a target concentration setting means for setting a target concentration based on the detection information of the cooling water temperature detection means are provided, and the concentration calculated by the concentration calculation means and the target concentration setting means The point is that a flow rate control means for controlling the flow rate adjustment means is provided based on the set target concentration.

In a second characteristic configuration, the cooling water temperature detecting means detects the cooling water temperature of the cooling water flowing into the absorber, and the cooling water temperature of the cooling water flowing into the condenser. Or a condenser cooling water temperature detecting means for detecting the outflow temperature, the concentration calculating means, the concentration of the absorbing liquid based on the detection information of the condenser cooling water temperature detecting means and the absorbing liquid temperature detecting means. The target concentration setting means is configured to calculate,
The target concentration is set based on the detection information of the absorber cooling water temperature detection means.

[0009]

The operation of the first characteristic configuration is as follows. Concentration of absorption liquid regenerated by regenerator (hereinafter, simply,
It may be referred to as the concentration of the absorbing liquid), the temperature of the absorbing liquid regenerated by the regenerator (hereinafter, also simply referred to as the temperature of the absorbing liquid), and the pressure of the regenerator are correlated. I have a relationship. Further, the pressure of the regenerator depends on the condensing temperature of the refrigerant vapor generated in the regenerator, and the condensing temperature is the temperature of the cooling water flowing through the absorber and the condenser (hereinafter, simply cooling water). Sometimes referred to as temperature). That is, there is a correlation between the concentration of the absorbing liquid, the temperature of the absorbing liquid, and the temperature of the cooling water.

The first characteristic configuration is based on the above viewpoint. That is, the concentration calculating means is configured to detect the temperature of the cooling water temperature detecting means and the absorbing liquid temperature detecting means based on the correlation among the concentration of the absorbing liquid, the temperature of the absorbing liquid, and the temperature of the cooling water. The concentration of the absorbing liquid is calculated from the detected temperature. Further, since the absorption capacity of the absorbing liquid varies depending on the temperature of the cooling water, it is necessary to adjust the concentration of the absorbing liquid to an appropriate concentration according to the temperature of the cooling water. Therefore, the target concentration setting means sets an appropriate target concentration according to the temperature detected by the cooling water temperature detecting means. Then, the flow rate control means controls the flow rate adjusting means so that the calculated concentration of the concentration calculation means becomes the target concentration.

The cooling water temperature detecting means and the absorbing liquid temperature detecting means can be provided, for example, so as to detect the temperature of the outer peripheral portion of the pipe forming the passage through which the cooling water and the absorbing liquid flow. .

The operation of the second characteristic structure is as follows. The condensation temperature of the refrigerant vapor generated in the regenerator has the best correlation with the inflow temperature or the outflow temperature of the cooling water with respect to the condenser. Therefore, the regenerator pressure is
There is the best correlation between the inlet and outlet temperatures of the cooling water for the condenser. Therefore, the concentration calculating means calculates the concentration of the absorbing liquid based on the condenser cooling water temperature detecting means for detecting the inflow temperature or the outflow temperature of the cooling water into the condenser, and the detection information of the absorbing liquid temperature detecting means. It is configured to do.

Further, the absorption capacity of the absorbing liquid can be predicted most accurately by the temperature of the cooling water flowing into the absorber. Therefore, the target concentration of the absorbing liquid is preferably set according to the inflow temperature of the cooling water into the absorber. Therefore, the target concentration setting means is configured to set the target concentration based on the detection information of the absorber cooling water temperature detecting means for detecting the inflow temperature of the cooling water into the absorber.

[0014]

According to the first characteristic configuration, the concentration of the absorbing liquid is obtained, and the concentration of the absorbing liquid becomes the target concentration set according to the temperature of the cooling water based on the obtained concentration. Since the flow rate of the refrigerant liquid is adjusted to
Further, the adjustment accuracy of the concentration of the absorbing liquid can be improved as compared with the conventional one, regardless of the fluctuation of the temperature of the cooling water. Moreover, since the cooling water temperature detecting means and the absorbing liquid temperature detecting means can be provided very easily,
The adjustment accuracy of the concentration of the absorbing liquid can be improved with a simple structure.

Further, according to the second characteristic configuration, the concentration of the absorbing liquid can be obtained with higher accuracy, and the target concentration can be made more accurately with an appropriate concentration according to the temperature of the cooling water. Since it can be set, the adjustment accuracy of the concentration of the absorbing liquid can be further improved.

[0016]

EXAMPLE An example in which the present invention is applied to a double-effect absorption refrigerator will be described below with reference to FIG. First,
The overall configuration of the double-effect absorption refrigerator will be described.

Above the high temperature regenerator 1 for heating the absorbing liquid by the burner B, a vertical cylindrical high temperature regenerator gas-liquid separator 2 is arranged, and the peripheral portion of the high temperature regenerator gas-liquid separator 2 is arranged. A vertical low temperature regenerator 3 is disposed in the low temperature regenerator 3, a low temperature regenerator gas-liquid separator 4 is disposed above the low temperature regenerator 3, and a vertical absorber 5 is disposed around the low temperature regenerator 3. An evaporator 6 is arranged below the absorber 5 and a condenser 7 is arranged above the absorber 5. The absorber 5 and the evaporator 6 are arranged in a closed space formed in the peripheral portion of the low temperature regenerator 3, and the lower portion of the closed space communicates with the evaporator 6 and the absorber 5. A liquid reservoir 5a is provided.

A high temperature regenerator gas-liquid separator 2 is connected to a high temperature regenerator 1 through an ascending flow path 8 of a refrigerant vapor and an absorbing liquid, and a low temperature regenerator 3 is connected.
And the low temperature regenerator gas-liquid separator 4 are communicated with each other.
In order to supply a low-concentration absorbing liquid (hereinafter sometimes referred to as a dilute liquid) from the absorber 5 to the high temperature regenerator 1, the liquid reservoir 5a
The high temperature regenerator 1 and the high temperature regenerator 1 are connected to each other through a dilute liquid supply path 10 with a solution pump 9 interposed therebetween, and a medium concentration absorption liquid (hereinafter, also referred to as a medium liquid) is transferred from the high temperature regenerator 1 to the low temperature regenerator 3. In order to supply, the high-temperature regenerator gas-liquid separator 2 and the lower part of the low-temperature regenerator 3 are connected by the medium-liquid supply path 11, and the high-concentration absorbent (hereinafter referred to as concentrated liquid) In some cases, the low temperature regenerator gas-liquid separator 4 and the absorbent sprayer 12 above the absorber 5 are connected by a concentrated liquid supply path 13 in order to supply (also sometimes referred to as).

A high temperature heat exchanger 14 for heating the dilute liquid flowing through the dilute liquid supply passage 10 by the dilute liquid flowing through the dilute liquid supply passage 11.
And a low temperature heat exchanger 15 for heating the dilute liquid flowing through the dilute liquid supply passage 10 by the dilute liquid flowing through the dilute liquid supply passage 13.

The partition wall 16 for partitioning the high temperature regenerator gas-liquid separator 2 and the low temperature regenerator 3 is used to heat the absorption liquid in the low temperature regenerator 3 with the refrigerant vapor in the high temperature regenerator gas liquid separator 2. It is formed on the heat transfer wall so that the refrigerant liquid generated by the condensation on the inner surface of the partition wall 16 flows down to the refrigerant liquid storage portion 2 a between the partition wall 16 and the inner cylinder 17.

Refrigerant liquid reservoir 2 of the high temperature regenerator gas liquid separator 2
a and the condenser 7 are connected by the refrigerant liquid supply passage 18, the low temperature regenerator gas-liquid separator 4 and the condenser 7 are connected by the refrigerant vapor supply passage 19, and the refrigerant liquid storage portion 7a below the condenser 7 is connected. And the refrigerant liquid spraying tool 20 of the evaporator 6 are connected by a refrigerant liquid supply passage 21.

The cooling water from the cooling water supply source 22 is absorbed by the absorber 5.
The cooling coil 23 and the cooling coil 24 are connected so that the cooling coil 23 inside the condenser 7 supplies the cooling coil 24 inside the condenser 7, and the cooling water supply path 25 is connected to them. The cooled coil 26 and the cooling target 27 are connected to each other by a cold water supply passage 28 having a pump so that the cold water from the cooled coil 26 in the evaporator 6 is supplied to the cooling target 27.

That is, the refrigerant vapor generated from the absorbing liquid in the high temperature regenerator 1 is condensed in the high temperature regenerator gas-liquid separator 2, and the refrigerant liquid is supplied to the condenser 7 through the refrigerant liquid supply passage 18, and the low temperature regenerator is supplied. The refrigerant vapor generated from the absorbing liquid in 3 is supplied to the condenser 7 through the refrigerant vapor supply path 19, and the refrigerant vapor is condensed by the action of the cooling coil 24. Then, the refrigerant liquid stored in the refrigerant liquid storage portion 7a is sprayed into the evaporator 6 by the refrigerant liquid spraying tool 20, and the sprayed refrigerant liquid is evaporated by the action of the cooled coil 26, and the vaporization heat thereof causes The water flowing through the cooled coil 26 is cooled.

On the other hand, the absorption liquid from the low temperature regenerator gas-liquid separator 4 is sprayed into the absorber 5 by the absorption liquid spraying tool 12 so that the sprayed absorption liquid absorbs the refrigerant vapor generated in the evaporator 6. ,
The absorption liquid that has absorbed the refrigerant vapor is sequentially supplied to the high temperature regenerator 1, the high temperature regenerator gas-liquid separator 2, the low temperature regenerator 3, and the low temperature regenerator gas-liquid separator 4 to separate and regenerate the refrigerant, The regenerated absorbent is sprayed into the absorber 5 by the absorbent sprayer 12. That is, the absorption liquid is absorbed into the absorber 5, the liquid reservoir 5a, the dilute liquid supply path 10, the high temperature regenerator 1, the high temperature regenerator gas-liquid separator 2, the medium liquid supply path 11, the low temperature regenerator 3, and the low temperature regenerator gas. The liquid separator 4, the concentrated liquid supply path 13, and the absorber 5 are configured to circulate through a circulation path that circulates in this order.
Therefore, the dilute liquid supply passage 10, the medium liquid supply passage 11 and the concentrated liquid supply passage 13 function as an absorbing liquid circulation passage. The absorption heat generated by the absorption liquid absorbing the refrigerant vapor in the absorber 5 is
The cooling coil 23 is given to the water flowing through and taken out to the outside.

Next, various control configurations of the double-effect absorption refrigerator will be described. A rare liquid flow rate adjusting valve V ₁ for adjusting the flow rate of the rare liquid flowing through the rare liquid supply passage 10, a flow rate adjusting valve V ₂ for adjusting the input amount of the fuel such as natural gas supplied to the burner B, and the refrigerant liquid. A refrigerant liquid flow rate adjusting valve V ₃ for adjusting the flow rate of the refrigerant liquid flowing through the supply passage 21 is provided. That is, the refrigerant liquid flow rate adjusting valve V ₃ functions as the flow rate adjusting means F. Further, the temperature of the cooling water flowing into the cooling coil 23 of the absorber 5 (hereinafter may be referred to as the absorber inflow temperature)
Absorber cooling water temperature sensor S ₁ as absorber cooling water temperature detecting means for detecting T ₁ , temperature of cooling water flowing out from the cooling coil 24 of the condenser 7 (hereinafter may be referred to as condenser outflow temperature) A condenser cooling water temperature sensor S ₂ as a condenser cooling water temperature detecting means for detecting T ₂ , and a concentrated liquid temperature sensor S for detecting a temperature T ₃ of the concentrated liquid flowing out from the low temperature regenerator gas-liquid separator 4. ₃ is provided. Therefore, the absorber 5
And a cooling water temperature detecting means Sw for detecting the temperature of the cooling water flowing through the condenser 7, and the absorber cooling water temperature sensor S.
₁ and a condenser cooling water temperature sensor S ₂ .
Further, the concentrated liquid temperature sensor S ₃ functions as an absorbing liquid temperature detecting means Sy for detecting the temperature of the absorbing liquid regenerated by the low temperature regenerator 3.

C in the figure indicates a control section using a microcomputer. The control operation by the control unit C will be described below.

First, the control operation for controlling the flow rate of the absorbing liquid circulating in the circulation path will be described. Control unit C
Controls the flow rate adjusting valve V ₂ to adjust the input amount according to the required refrigerating capacity. Further, the controller C stores the opening degree of the rare liquid flow rate adjusting valve V ₁ preset according to the input amount and the cooling water temperature T ₁ .
Then, the control unit C controls the opening degree of the dilute liquid flow rate adjusting valve V ₁ on the basis of the input amount and the cooling water temperature T ₁ detected by the absorber cooling water temperature sensor S ₁ to determine the circulation amount of the absorbing liquid. To control.

Next, the control operation for controlling the concentration of the absorbing liquid supplied to the absorber 5 will be described. The control unit C
Utilizing the above, a concentration calculating means 31, a target concentration setting means 32, an adjustment opening degree calculating means 33, and a valve control means 34, which will be described later, are configured.

The concentration D of the concentrated liquid regenerated by the low temperature regenerator 3 (that is, the absorption liquid supplied to the absorber 5), the temperature T _{3 of the} concentrated liquid regenerated by the low temperature regenerator ₃ and the cooling water. It was found by experiments that there is a relationship as shown in FIG. 2 among the three condenser outflow temperatures T ₂ .

The concentration calculating means 31 is based on the relationship shown in FIG.
Then, the condenser cooling water temperature sensor S ₂Cooling water detected by
Outflow temperature T of the condenser₂And concentrated liquid temperature sensor S₃Detected by
Concentrated liquid temperature T₃And the concentration D of the concentrated liquid is calculated.

The target concentration setting means 32 sets the target concentration Dp based on the cooling water absorber inflow temperature T ₁ detected by the cooling water temperature sensor S ₁ . Specifically, the target concentration setting means 32 sets the target concentration Dp to, for example, 58% when the absorber inflow temperature temperature T _{1 of} the cooling water is 24 ° C.
It is set to 60% at ° C and 62% at 32 ° C.

The adjustment opening calculation means 33 is the concentration calculation means 3
Based on the deviation between the concentrated liquid concentration D calculated by 1 and the target concentration Dp changed and set by the target concentration setting means 32, the concentrated liquid concentration D
The adjustment opening degree dW of the refrigerant liquid flow rate adjustment valve V ₃ for making the target concentration Dp is calculated. Then, the valve control means 34 determines the opening degree W of the refrigerant liquid flow rate adjusting valve V ₃ by the adjustment opening degree calculating means 33.
The control is performed so as to change only the adjustment opening dW calculated by.
That is, the adjustment opening calculation means 33 and the valve control means 34 function as a flow rate control means for controlling the refrigerant liquid flow rate adjusting valve V ₃ so that the concentrated liquid concentration D becomes the set target concentration Dp.

[Other Embodiments] Next, other embodiments will be listed. In the above embodiment, the condenser cooling water temperature detecting means S
_{Although 2} is provided to detect the temperature T ₂ of the cooling water flowing out from the cooling coil 24, it may be provided instead to detect the temperature of the cooling water flowing into the cooling coil 24.

In the above embodiment, the absorption liquid temperature sensor Sy for detecting the temperature of the absorption liquid regenerated by the low temperature regenerator 3.
As the concentrated liquid temperature sensor S ₃ for detecting the temperature T ₃ of the concentrated liquid flowing out from the low temperature regenerator gas-liquid separator 4, the temperature of the absorbing liquid regenerated by the low temperature regenerator 3 and the low temperature regeneration Since there is a correlation with the temperature of the cooler 3 or the low-temperature regenerator gas-liquid separator 4, a temperature sensor that detects the temperature of the low-temperature regenerator 3 or the low-temperature regenerator gas-liquid separator 4 is applied as the absorption liquid temperature sensor Sy. You may.

Although the refrigerant liquid flow rate adjusting valve V ₃ is applied as the flow rate adjusting means F in the above embodiment, an inverter pump capable of adjusting the discharge amount may be applied instead of this.

Since the gradient of the temperature of the cooling water flowing through the absorber 5 and the condenser 7 is almost constant, the temperature of the cooling water for calculating the concentrated liquid concentration D and the target concentration D
As the temperature of the cooling water for setting p, the temperature detected at any position on the flow path of the cooling water may be used. Alternatively, an average value of temperatures detected at a plurality of positions in the flow path may be used.

The absorber 5, the evaporator 6 and the condenser 7 are
The high temperature regenerator gas / liquid separator 2, the low temperature regenerator 3 and the low temperature regenerator gas / liquid separator 4 may be separately installed.

The refrigerant and the absorbing liquid can be appropriately selected from known ones.

In the above embodiment, the case where the present invention is applied to the double-effect absorption refrigerator is illustrated, but it is also possible to apply to the single-effect absorption refrigerator.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a block diagram of a double-effect absorption refrigerator.

FIG. 2 is a diagram showing the relationship between the concentration of the concentrated liquid, the temperature of the concentrated liquid, and the condenser outlet temperature of the cooling water.

[Explanation of symbols]

3 Regenerator 5 Absorber 5a Liquid reservoir 6 Evaporator 7 Condenser 10, 11, 13 Absorbing liquid circulation path 21 Refrigerant liquid supply path 31 Concentration calculating means 32 Target concentration setting means 33, 34 Flow control means F Flow rate adjusting means S ₁ Absorber cooling water temperature detecting means S ₂ Condenser cooling water temperature detecting means Sw Cooling water temperature detecting means Sy Absorbing liquid temperature detecting means

Front page continuation (72) Inventor Katsuyuki Sakane 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Within Osaka Gas Co., Ltd.

Claims (2)

[Claims] 1. An evaporator (6) for evaporating a refrigerant liquid, an absorber (5) for absorbing a refrigerant vapor generated in the evaporator (6) into an absorbing liquid, the evaporator (6) and the absorption. A reservoir (5a) communicating with the container (6) and a regenerator (3) for regenerating the absorption liquid diluted with the refrigerant are provided, and the reservoir (5a) and the regenerator (3) are provided. And the absorber (5) is an absorption liquid circulation path (10), (11), (13).
And a condenser (7) and the evaporator (6) are connected by a refrigerant liquid supply path (21) having a flow rate adjusting means (F) interposed therebetween. Cooling water temperature detecting means (Sw) for detecting the temperature of the cooling water flowing through the absorber (5) and the condenser (7).
An absorbing liquid temperature detecting means (Sy) for detecting the temperature of the absorbing liquid regenerated by the regenerator (3), the cooling water temperature detecting means (Sw) and the absorbing liquid temperature detecting means (Sy).
The concentration calculating means (31) for calculating the concentration of the absorbing liquid based on the detection information of 1. and the target concentration setting means (32) for setting the target concentration based on the detection information of the cooling water temperature detecting means (Sw). The density provided and calculated by the density calculating means (31) and the target density setting means (32)
An absorption chiller provided with flow rate control means (33), (34) for controlling the flow rate adjusting means (F) based on the target concentration set in (1). 2. The absorber cooling water temperature detecting means (S ₁ ) for detecting the inflow temperature of the cooling water into the absorber (5), and the cooling water temperature detecting means (Sw) for detecting the inflow temperature of the cooling water. And a condenser cooling water temperature detecting means (S ₂ ) for detecting an inflow temperature or an outflow temperature to the condenser (7), wherein the concentration calculating means (31) is the condenser cooling water temperature detecting means (S _2). ) And the concentration of the absorbing liquid based on the detection information of the absorbing liquid temperature detecting means (Sy), and the target concentration setting means (32)
The absorption refrigerating machine according to claim 1, wherein the target concentration is set based on the detection information of the absorber cooling water temperature detecting means (S ₁ ).