JP3321911B2 - Absorption refrigeration equipment - 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 a regenerator provided with a heating device, an absorber, a condenser, and an evaporator. The present invention relates to an absorption refrigeration apparatus capable of responding to both of them immediately and suppressing unnecessary heating.

[0002]

2. Description of the Related Art Generally, a regenerator using a heating device as a heat source,
2. Description of the Related Art In an absorption refrigeration system including an absorber, a condenser, an evaporator, a heat exchanger, and the like, conventionally, a heating amount of a heating device is controlled based on a load such as chilled water.

[0003] However, in this case, the initial capacity is reduced due to aging such as clogging of the absorber and the evaporator. For this reason, even if the heating amount is increased unnecessarily, only an ineffective refrigerant is generated, resulting in unnecessary heating. That is, even if the amount of heating is increased and a large amount of liquid refrigerant is supplied to the refrigerant tank, only overflow occurs, and so-called wasted heating is caused.

Therefore, a method has been proposed in which when the amount of refrigerant in the refrigerant tank exceeds a predetermined value, the maximum heating amount is gradually reduced from a predetermined value, thereby preventing waste cooking from occurring. (For example, Japanese Patent Application No. 4-1730)
No. 14).

[0005]

However, in this method, it takes time to find an appropriate heating amount corresponding to aging such as clogging of an absorber or an evaporator. During that time, invalid refrigerant is generated. , Heating is wasted. Moreover, every time the cooling operation is performed, it is necessary to perform a similar operation for searching for an appropriate heating amount, which is inefficient. Further, it was not possible to immediately respond to a temporal change (for example, a rapid change in the outside temperature or a shortage of water).

The present invention has been made in view of the above circumstances, by associating the rate of change in the upper limit heating capacity of the heating device with the rate of change in the chilled water temperature of the chilled water pipe in accordance with the concentration of the solution or the amount of the refrigerant. It is an object of the present invention to provide an absorption refrigeration apparatus that can distinguish between aging and aging and can respond to both immediately and suppress unnecessary heating.

[0007]

That is, the present invention comprises a regenerator having a heating device, an absorber, a condenser, and an evaporator. The cold water is taken out from the evaporator and the concentration of the solution or In an absorption refrigerating apparatus that controls the heating capacity of the heating apparatus according to the amount of the refrigerant, the rate of change of the upper limit heating capacity of the heating apparatus according to the concentration of the solution or the rate of change of the amount of the refrigerant and the temperature of the chilled water. Is provided by providing a heating amount control means for corresponding to.

[0008]

With the above arrangement, the present invention distinguishes between aging and aging and immediately responds to both, depending on the concentration of the solution or the amount of refrigerant and the speed of change of the chilled water temperature of the chilled water pipe. Unnecessary heating can be suppressed by matching the changing speed of the heating upper limit capability of the heating device.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a small-capacity water-lithium salt absorption refrigeration system for home use or the like. Reference numeral 1 denotes a regenerator provided with a heating device 2 for cooling such as a burner, and an exhaust hood 3 of the heating device 2. Is a configuration used in combination with the exhaust hood of the heating device 4 for heating arranged in parallel. 5 is a condenser connected to the regenerator 1 and using the refrigerant vapor as a liquid refrigerant. The condenser 5 is connected to a refrigerant tank 8 facing an evaporator 7 via a refrigerant pipe 6. Reference numeral 9 denotes an absorber connected to the evaporator 7 via a communication passage 10. Above the absorber 9, a concentrated solution pipe 11 for introducing a concentrated solution produced by evaporating the refrigerant in the regenerator 1 is used as a solution heat pipe. Piping through the exchanger 12,
And a solution tank 1 for collecting a dilute solution below the absorber 9.
3 and the solution tank 13 is connected to the solution heat exchanger 12
The dilute solution pipe 14 returning to the regenerator 1 through the pipes forms a solution circulation path. Reference numeral 15 denotes a refrigerant circulation pipe having a refrigerant pump 16 provided at a lower end of the refrigerant tank 8, and a leading end thereof is connected to a spraying device 17 of the evaporator 7. Further, a temperature sensor 19 for detecting the temperature of the cold water is attached to an outlet 18a of the cold water pipe 18 facing the evaporator 7, and a liquid level sensor 20 is attached to the refrigerant tank 8. The cold water pipe 18 is guided to an appropriate number of indoor units 21, and this return pipe constitutes a circulation path returning to the evaporator 7 via the storage tank 22 and the switching valve 23A. Further, at the time of heating, a heating pipe 25 through which hot water flows to the hot water heat exchanger 24 of the heating device 4 for heating through the switching valve 23B.
Use Reference numeral 26 denotes a control device that guides outputs of the temperature sensor 19, the liquid level sensor 20, and the like, and controls the heating device 2 and the like. Reference numeral 27 denotes a cooling fan for cooling the absorber 9 and the condenser 5. Reference numeral 29 denotes a cooling water pipe of the absorber 9. Further, an outside air temperature sensor 30 for detecting an outside air temperature is provided below the hot water heat exchanger 24 in FIG. 1, and the temperature sensor 30 is connected to the control device 26 (not shown).

Next, the operation will be described. First, when the absorption type refrigerating apparatus is operated, the solution (dilute solution) is boiled in the regenerator 1 by, for example, heating of the heating device 2 for cooling, and the evaporated refrigerant vapor and the concentrated refrigerant vapor are condensed. This produces a solution. This refrigerant vapor is led to the condenser 5 and is condensed into a refrigerant liquid. This refrigerant liquid accumulates in the refrigerant tank 8 via the refrigerant pipe 6, and the refrigerant liquid fed from the refrigerant tank 8 by the refrigerant pump 16 is sprayed into the evaporator 7 with the spraying device 17, and is generated at the time of spraying. The heat transfer tube portion of the cold water pipe 18 is cooled using latent heat of vaporization to obtain cold water, and the cold water is guided to the indoor unit 21 to perform cooling.

On the other hand, the refrigerant vapor generated in the evaporator 7 flows to the absorber 9 through the communication path 10. In the absorber 9, the concentrated solution obtained in the regenerator 1 is guided and sprayed through the concentrated solution pipe 11, and absorbs the refrigerant vapor in the vessel to form a dilute solution. The diluted solution is used as a liquid circulation returning to the regenerator 1 via the solution tank 13 and the solution heat exchanger 12.

In this case, the cooling operation control is performed by controlling the heating amount of the regenerator heating device 2 which is the basis for generating the liquid refrigerant accumulated in the refrigerant tank 8. This is because the liquid level is detected by the liquid level sensor 20 disposed on a predetermined amount of the refrigerant liquid level Lee near the outlet of the overflow pipe 28 that returns to the solution tank 13 connected to the upper part of the refrigerant tank 8, The detection is performed in combination with the detection of the chilled water temperature by the temperature sensor 19 disposed in the chilled water pipe 18 that exits.

That is, the overflow of the refrigerant liquid from the overflow pipe 28 is based on the judgment that the heating amount of the heating device 2 is excessive (wasteful cooking) just to obtain the refrigerant liquid. First, it is detected whether or not the outlet temperature of the cold water pipe 18 has reached a set temperature, and the heating amount is changed stepwise in a range from the maximum heating amount to the minimum heating amount so as to reach the setting temperature.
Further, it is detected whether or not the level of the refrigerant stored in the refrigerant tank 8 reaches a predetermined value Lee, and the temperature of the outlet is detected by the temperature sensor 19 with the cold water pipe 18 of the evaporator 7, and the value is sent to the control device 26. Based on the input, the heating amount of the heating device 2 is controlled based on the input, so that an appropriate refrigerant liquid level is obtained so that the refrigerant liquid does not overflow from the refrigerant tank 8. Further, the appropriate heating amount at this time is stored in the control device 26 as the upper limit heating amount, and at the next cooling operation, the control is started in consideration of the upper limit heating amount, so that the appropriate heating considering the aging is performed. The maximum heating amount is set immediately.

Now, this heating amount control operation will be described with reference to FIGS.
The following is a detailed description based on the flowchart of the cooling operation control program shown in FIG.

First, in the cooling operation, the detection of the chilled water temperature Tw is performed by a temperature sensor 19 for detecting the chilled water temperature at the outlet side of the evaporator 7. The heating amount Q is set to the maximum heating amount Qmax and the minimum heating amount Q so that the cold water temperature Tw becomes the set temperature Tws.
PID (Proportional, Integral, Differential) control is performed between these two values.

Here, first, the absorber 9 and the evaporator 7
Are effective enough, but the absorber 9 and the evaporator 7
Due to aging such as clogging, the initial capacity decreases, and as the cold water temperature rises, the heating amount Q increases, and as the heating amount Q increases, the refrigerant liquid accumulates in the refrigerant tank 8. Therefore, the liquid level sensor 20 disposed in the refrigerant tank 8 detects the liquid level of the refrigerant immediately before the overflow.

When the liquid level of the refrigerant becomes equal to or higher than a predetermined value (Lee), the chilled water temperature Tw becomes equal to the previous chilled water temperature Tw1
It is determined whether or not the temperature is within the range, and if it is within this range, the cold water temperature Tw is stored as Tw1. If the cold water temperature Tw is 7 ° C. or lower, Tw1 is set to 7 ° C., and then the upper limit heating amount Qmemo stored during the previous operation is reduced by a certain amount α1. Hereinafter, when the refrigerant liquid level does not drop, the heating amount Q is reduced every predetermined time. At this time, if the upper limit heating amount Qmemo is less than the minimum heating amount Qmin, the minimum heating amount Qmin is stored as the upper limit heating amount Qmemo.

In this way, when the refrigerant liquid level becomes equal to or higher than the predetermined value (Lee) and the upper limit heating amount Qmemo is adjusted, the refrigerant liquid level becomes lower than the predetermined value (Lee).
It is determined whether or not w is equal to or more than a certain temperature difference ΔT from the previous cold water temperature Tw1, and if the difference between the cold water temperature Tw and the previous cold water temperature Tw1 is less than the temperature difference ΔT, the cooling capacity is reduced. It is not necessary to increase the heating amount Q because it does not drop much, but if the difference between the chilled water temperature Tw and the previous chilled water temperature Tw1 is equal to or greater than the temperature difference ΔT, the heating amount Q is increased to increase the cooling capacity. Let it recover. To this end, the upper limit heating amount Qmemo stored during the previous operation is increased by a certain amount α2, and when the upper limit heating amount Qmemo is equal to or greater than the maximum heating amount Qmax, the maximum heating amount Qmax is stored as the upper limit heating amount Qmemo.

In this way, an appropriate upper limit heating amount Qmemo corresponding to aging is searched for and the value is stored.

In the cooling operation program described above, the heating amount control for searching for an appropriate upper limit heating amount Qmemo corresponding to aging has been described. The present invention can be applied to a rapid change or a temporal change such as a voltage change.

As described above, when the amount of refrigerant in the refrigerant tank exceeds a predetermined value, the amount of heating (α1) is reduced by a certain amount (α1). Thereafter, when the chilled water temperature is less than a predetermined value and the chilled water temperature is equal to or more than a certain temperature difference, the heating amount is increased by a certain number (α2) (see FIG. 4).

The process of determining α1 and α2 for a certain quantity will be described with reference to FIG.

In order to determine α1 and α2, the level of the refrigerant in the refrigerant tank 8 (FIG. 1) is determined in step S1. In this refrigerant liquid level, level 1 (low) is represented by l =
1, 1 = 2 for level 2 (medium), 1 = 3 for level 3 (high)
And

When the liquid level is obtained, the rate of change dTw / dt of the chilled water temperature in the chilled water officer 18 is determined.
The rate of change is J = 1 when dTw / dt ≦ a <0, J = 2 when a <dTw / dt <b, and dTw
The case where / dt ≧ b> 0 is set to three types of J = 3. Here, a = a negative constant and b = a positive constant. Therefore, the case where dTw / dt ≦ a <0 when J = 1 means a case where the temperature of the chilled water drops greatly, and the case where JT = 3
The case where dt ≧ b> 0 means the case where the temperature rise is large. J = 2 indicates the case where the temperature change rate is between the constant a and the constant b, that is, the case of the change rate during normal operation.

When the rate of change of the chilled water temperature is determined, the process proceeds to step S3, where α1, α2 = (l, J), and the level l and the rate of change J of the chilled water temperature are changed to (1, 2, 2). 3) Determine α1 and α2 using the following table.

Determination of α1, α2: J 1 2 3 1 1 α1 = ΔQ α1 = ΔQ α1 = ΔQ α2 = 2ΔQ α2 = ΔQ α2 = 1 / 2ΔQ L 2 α1 = ΔQ α1 = ΔQ α1 = ΔQ (l) α2 = ΔQ α2 = ΔQ α2 = ΔQ 3 α1 = 1 / 2ΔQ α1 = ΔQ α1 = 2ΔQ α2 = ΔQ α2 = ΔQ α2 = ΔQ Based on α1 and α2 thus obtained, Qmem
o (a value obtained by subtracting the heating amount corresponding to the aging during the operation at the previous stage from the predetermined maximum heating amount Qmax) is obtained. See FIG.

From the above table, when the amount of refrigerant is large, the heating upper limit is rapidly reduced when the chilled water temperature rises rapidly, and the change in the heating upper limit is gently reduced when the chilled water temperature falls below a certain value. Do. When the amount of the refrigerant is small, the heating upper limit value is sharply increased when the temperature of the chilled water is sharply decreased, and is slowly increased when the temperature is slower than a fixed value.

[0029]

As described above, according to the present invention,
According to the rate of change of the concentration of the solution or the amount of the refrigerant and the chilled water temperature of the chilled water pipe, by changing the rate of change of the heating upper limit capacity of the heating device, the aging and the aging are distinguished. To avoid unnecessary heating. That is, when distinguishing between aging and aging, and when the original normal state is restored due to a sudden change in the outside air temperature, a decrease in water pressure or a shortage of water, the capacity of the absorber increases, and the pressure of the absorber decreases. As the cooling capacity rises sharply, the water temperature drops sharply. Therefore, when the water temperature suddenly drops while the above-described time-dependent change in the capacity is occurring, the recovery of the heating capacity can be quickened by controlling the recovery of the limited capacity. This makes it possible to immediately search for an appropriate heating amount that matches the current capacity, so that useless heating can be suppressed and high-efficiency operation can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of an absorption refrigerator according to the present invention.

FIG. 2 is a flowchart showing a part of an example of a cooling operation control program.

FIG. 3 is a flowchart showing the rest of the cooling operation control program shown in FIG. 2;

FIG. 4 is a flowchart showing a process for obtaining an increase and a decrease in an upper limit heating amount Qmemo.

FIG. 5 is a flowchart showing a process of determining a certain number of α1 and α2 required for obtaining an increase or decrease of the upper limit heating amount Qmemo.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Regenerator 2 ... Heating apparatus (heating apparatus for cooling) 5 ... Condenser 7 ... Evaporator 8 ... Refrigerant tank 9 ... Absorber 18 ... Cold water pipe 19 ... Cold water temperature detector 24 ... … Hot water heat exchanger 26… heating amount control device 30… outside air temperature sensor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Shozo Kato 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Yasuo Takase 2-18-3 Keihanhondori, Moriguchi-shi, Osaka (72) Inventor Kazuhiro Tajima 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Tetsuo Miyamoto 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric (56) References JP-A-4-68272 (JP, A) JP-A-59-173666 (JP, A) JP-A-58-210464 (JP, A) JP-A-62-171766 (JP, A) U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 15/00 306

Claims (2)

(57) [Claims] 1. A regenerator having a heating device, an absorber,
An absorption refrigeration system comprising a condenser and an evaporator, taking out cold water from the evaporator and controlling the heating capacity of the heating device according to the concentration of the solution or the amount of the refrigerant. An absorption refrigeration system, comprising: a heating amount control means for making a change speed of a heating upper limit capability of the heating device correspond to a change speed of an amount and a cooling water temperature. 2. When the concentration of the solution is high or the amount of the refrigerant is large, when the rising speed of the chilled water temperature in the chilled water pipe is rapid, the decreasing speed of the heating upper limit of the heating device is increased, If the rate of change of the chilled water temperature changes below a certain value, the rate of decrease of the heating upper limit is slowed down.Moreover, when the concentration of the solution is low or the amount of the refrigerant is small, the temperature of the chilled water decreases. 2. The absorption refrigeration system according to claim 1, wherein the rate of increase of the heating upper limit value is increased when the temperature is abrupt, and the rate of increase of the heating upper limit value is delayed when the rate of change is slower than a certain value.