JPH0719652A - Absorption refrigerating machine - Google Patents

Abstract

PURPOSE:To immediately deal with an aging change of recovery such as abrupt change of the outside-air temperature, suspension of water supply, a decrease in water pressure and to rapidly recover to a normal capacity when it is returned to a normal state. CONSTITUTION:An absorption type refrigerator has a regenerator 1 having a heater 2, an absorber 9, a condenser 5, and an evaporator 7 in such a manner that chilled water from the evaporator 7 is removed, and heating capacity of the heater 2 is controlled according to concentration or solution or amount of refrigerant liquid, and comprises heating amount control means 26 for dealing with speed change of heating upper limit capacity of the heater 2 in response to the change speed of the concentration of the solution or the amount of the refrigerant liquid and chilled water temperature with respect to the heating capacity of the heater 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigeration system having a regenerator equipped with a heating device, an absorber, a condenser, and an evaporator, and distinguishes between aging and aging. The present invention relates to an absorption refrigeration system capable of immediately responding to both of them and suppressing wasteful heating.

[0002]

2. Description of the Related Art Generally, a regenerator using a heating device as a heat source,
In an absorption type refrigeration system including an absorber, a condenser, an evaporator, a heat exchanger, etc., conventionally, a load of cold water or the like is used as a control target of a heating amount of a heating device.

However, in this case, the initial capacity is lowered due to secular change such as clogging of the absorber and the evaporator. For this reason, even if the amount of heating is increased unnecessarily, only ineffective refrigerant is generated, resulting in useless heating. That is, even if the amount of heating is increased and a large amount of liquid refrigerant is supplied to the refrigerant tank, it only overflows, resulting in so-called waste cooking of heating.

Therefore, there has been proposed a method for preventing waste cooking by gradually reducing the maximum heating amount from a predetermined value when the amount of refrigerant in the refrigerant tank exceeds a predetermined value. (For example, Japanese Patent Application No. 4-1730
(See No. 14).

[0005]

However, in this method, it takes time to find an appropriate heating amount corresponding to the secular change such as clogging of the absorber and the evaporator, and during that time, the ineffective refrigerant is generated. , Waste of heating. In addition, it is inefficient because it is necessary to perform the same work each time to search for an appropriate amount of heating each time the cooling operation is performed. In addition, it was not possible to immediately respond to changes over time (for example, rapid changes in outside temperature or insufficient water volume).

In view of the above-mentioned circumstances, the present invention makes the change rate of the heating upper limit capacity of the heating device correspond to the change rate of the concentration of the solution or the liquid amount of the refrigerant and the change of the cold water temperature of the cold water pipe. It is an object of the present invention to provide an absorption type refrigerating apparatus which can discriminate between aged deterioration and aged deterioration and can respond to both of them immediately to 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 refrigeration system that controls the heating capacity of the heating device by the liquid amount of the refrigerant, the rate of change of the heating upper limit capacity of the heating device according to the concentration of the solution or the rate of change of the liquid amount of the refrigerant and the cold water temperature. Is provided with a heating amount control means.

[0008]

With the above-described structure, the present invention distinguishes between aging and aging, and immediately responds to both, depending on the concentration of the solution or the amount of the refrigerant and the rate of change of the cold water temperature of the cold water pipe. Unnecessary heating can be suppressed by making the changing speed of the heating upper limit capacity of the heating device correspond.

[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 household use, and 1 is a regenerator equipped with a heating device 2 for cooling such as a burner, and an exhaust hood 3 of the heating device 2. Is used together with the exhaust hood of the heating device 4 for heating arranged in parallel. A condenser 5 connected to the regenerator 1 uses a refrigerant vapor as a liquid refrigerant, and a condenser tank 8 facing an evaporator 7 is connected to the condenser 5 via a refrigerant pipe 6. Reference numeral 9 denotes an absorber which is connected to the evaporator 7 via a communication passage 10. Above the absorber 9, a concentrated solution pipe 11 for guiding a concentrated solution generated by evaporating the refrigerant in the regenerator 1 is used as a solution heat exchanger. Piping through the exchanger 12,
Moreover, the solution tank 1 for collecting the dilute solution below the absorber 9
3, the solution tank 13 is connected to the solution heat exchanger 12
A dilute solution pipe 14 returning to the regenerator 1 via the above is provided to form a solution circulation path. Reference numeral 15 is a refrigerant circulation pipe having a refrigerant pump 16 arranged at the lower end of the refrigerant tank 8, the tip of which is connected to the spraying device 17 of the evaporator 7. Further, a temperature sensor 19 for detecting the cold water temperature is attached to the outlet portion 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 that returns to the inside of the evaporator 7 via the storage tank 22 and the switching valve 23A. Further, at the time of heating, heating pipe 25 in which hot water flows through the switching valve 23B to the hot water heat exchanger 24 of the heating device 4 for heating.
To use. A control device 26 guides the 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 that cools the absorber 9 and the condenser 5. Reference numeral 29 is a cooling water pipe for the absorber 9. Further, an outside air temperature sensor 30 for detecting the 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 although not shown.

To explain this action, first, when the absorption type refrigerating device is operated, for example, the solution (dilute solution) is boiled in the regenerator 1 by the heating of the heating device 2 for cooling, and the concentrated refrigerant vapor and concentrated vapor are concentrated. Form a solution. This refrigerant vapor is guided to the condenser 5 and condensed to become 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 by means of the spraying device 17, and is generated at the time of this spraying. The latent heat of vaporization is used to cool the heat transfer pipe portion of the cold water pipe 18 to obtain cold water, and this cold water is guided to the indoor unit 21 for cooling.

On the other hand, the refrigerant vapor generated in the evaporator 7 flows into the absorber 9 through the communication passage 10. In the absorber 9, the concentrated solution obtained in the regenerator 1 is guided by the concentrated solution pipe 11 and sprinkled, and the refrigerant vapor in the container is absorbed to form a diluted solution. The diluted solution is circulated through the solution tank 13 and the solution heat exchanger 12 and returned to the regenerator 1 for circulation.

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 producing the liquid refrigerant accumulated in the refrigerant tank 8. This is because the liquid level sensor 20 arranged on a predetermined amount of the refrigerant liquid level Lee near the outlet of the overflow pipe 28 returning to the solution tank 13 connected to the upper portion of the refrigerant tank 8 detects the liquid level from the evaporator 7. The temperature sensor 19 provided on the outgoing cold water pipe 18 detects the cold water temperature in a comprehensive manner.

That is, the fact that the refrigerant liquid overflows from the overflow pipe 28 is based on the judgment that the heating amount of the heating device 2 is excessive (waste cooking) to obtain the refrigerant liquid. First, it is detected whether the outlet temperature of the cold water pipe 18 has reached the set temperature, and the heating amount is changed stepwise within the range of the maximum heating amount to the minimum heating amount so as to reach the setting temperature.
Further, it is detected whether or not the liquid level of the refrigerant accumulated in the refrigerant tank 8 reaches a predetermined value Lee, the temperature of the outlet is detected by the temperature sensor 19 in the cold water pipe 18 of the evaporator 7, and the value is notified to the controller 26. It is input and the heating amount of the heating device 2 is controlled based on this input to obtain an appropriate refrigerant liquid level so that the refrigerant liquid does not overflow from the refrigerant tank 8. Further, the proper heating amount at this time is stored in the control device 26 as the upper limit heating amount, and at the time of the next cooling operation, the upper limit heating amount is taken into consideration to start the control so that an appropriate change considering secular change is taken into consideration. The upper limit heating amount will be 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 cold water temperature Tw is detected by the temperature sensor 19 which detects the cold 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, derivative) control between min and.

Here, first, the absorber 9 and the evaporator 7
Etc. are fully effective, but absorber 9 and evaporator 7
The initial capacity is deteriorated due to the secular change such as clogging, and the heating amount Q increases as the cold water temperature rises, and as the heating amount Q increases, the refrigerant liquid accumulates in the refrigerant tank 8. Therefore, the liquid level sensor 20 arranged in the refrigerant tank 8 detects the liquid surface of the refrigerant immediately before it overflows.

When the liquid level of the refrigerant exceeds a certain value (Lee), the cold water temperature Tw is the same as the previous cold water temperature Tw1 and 7.
It is determined whether or not the temperature is between 0 ° C., and if it is within this range, the cold water temperature Tw is stored as Tw1. When the cold water temperature Tw is 7 ° C. or lower, Tw1 = 7 ° C., and then the upper limit heating amount Qmemo stored in the previous operation is reduced by a certain amount α1. Hereinafter, when the liquid level of the refrigerant does not drop, the heating amount Q is reduced every predetermined time. At this time, when the upper limit heating amount Qmemo becomes less than or equal to the minimum heating amount Qmin, the minimum heating amount Qmin is stored as the upper limit heating amount Qmemo.

In this way, when the coolant liquid level becomes equal to or higher than the constant value (Lee) and the upper limit heating amount Qmemo is adjusted and the coolant liquid level becomes lower than the constant value (Lee), the cold water temperature T
It is determined whether or not w is a certain temperature difference ΔT or more compared to 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 Since it does not fall so much, it is not necessary to increase the heating amount Q, but when the difference between the cold water temperature Tw and the previous cold water temperature Tw1 is the temperature difference ΔT or more, the heating amount Q is increased to increase the cooling capacity. Restore. To this end, the upper limit heating amount Qmemo stored in the previous operation is increased by a certain amount α2, and when the upper limit heating amount Qmemo becomes equal to or more 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 the secular change is searched for and the value is stored.

In the cooling operation program described above, the heating amount control for searching for the appropriate upper limit heating amount Qmemo corresponding to the secular change has been described. However, this heating amount control is performed by water shortage due to water cutoff or water pressure drop, and outside air temperature. It can also be applied to abrupt changes or changes with time such as voltage fluctuations.

As for the point that the appropriate upper limit heating amount Qmemo is increased or decreased, as described above, when the refrigerant amount in the refrigerant tank becomes a predetermined value or more, the heating amount is reduced by a certain amount (α1), and conversely. After that, when the temperature is lower than a predetermined value and the cold water temperature is higher than a certain temperature difference, the heating amount is increased by a certain quantity (α2) (see FIG. 4).

Now, the process of determining the certain quantities α1 and α2 will be described with reference to FIG.

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

After the liquid level is obtained, the rate of change dTw / dt of the cold water temperature of the cold water Tw in the cold water officer 18 is obtained.
This change rate is set to J = 1 when dTw / dt ≦ a <0, J = 2 when a <dTw / dt <b, and dTw
When / dt ≧ b> 0, there are three types of J = 3. Here, a = a negative constant and b = a positive constant. Therefore, the case of dTw / dt ≦ a <0 of J = 1 means that the cooling water temperature decreases largely, and dTw / dt of J = 3.
The case of dt ≧ b> 0 means that the temperature rises largely. J = 2 indicates that the temperature change rate is between the constant a and the constant b, that is, the change rate during normal operation.

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

Determination of α1 and α2: J 1 2 3 1 1 α1 = ΔQ α1 = ΔQ α1 = ΔQ α2 = 2ΔQ α2 = ΔQ α2 = 1 / 2ΔQ R 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 (the value obtained by subtracting the heating amount corresponding to the secular change during the operation in 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 value is rapidly decreased when the cold water temperature rises sharply, and the change of the heating upper limit value is moderate when the cold water temperature falls below a certain value. To do. When the amount of the refrigerant is small, the heating upper limit value is rapidly increased when the cold water temperature is drastically lowered, and is slowly increased when the cold water temperature is slower than a certain value.

[0029]

As described above, according to the present invention,
Depending on the concentration of the solution or the amount of the refrigerant and the rate of change of the cold water temperature of the cold water pipe, by corresponding the rate of change of the heating upper limit capacity of the heating device, to distinguish between aging and aging, both. It is possible to immediately suppress the useless heating. In other words, while distinguishing the secular change from the secular change, when the original normal state is restored from a sudden change in the outside air temperature, a decrease in water pressure, and a lack of water volume, the capacity of the absorber increases and the pressure of the absorber decreases. As a result, the cooling capacity rapidly rises, and the water temperature sharply drops. Therefore, when the water temperature sharply decreases while the capacity is being limited due to the above-described change with time, the heating capacity can be recovered more quickly by performing control to accelerate the recovery of the limiting capacity. As a result, it is possible to immediately search for an appropriate heating amount that matches the current capacity, so that useless heating can be suppressed and highly efficient operation can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an 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 program for cooling operation control shown in FIG.

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

FIG. 5 is a flow chart showing a process of determining a certain quantity α1 and α2 necessary for increasing or decreasing the upper limit heating amount Qmemo.

[Explanation of symbols]

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shozo Kato 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (72) Inventor Yasuo Takase 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Denki Incorporated (72) Inventor Kazuhiro Tajima 2-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Tetsuo Miyamoto 2-18-2 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. A regenerator having a heating device, and an absorber,
In an absorption refrigeration system that consists of a condenser and an evaporator, draws cold water from the evaporator, and controls the heating capacity of the heating device according to the concentration of the solution or the liquid amount of the refrigerant, the concentration of the solution or the liquid of the refrigerant. An absorption type refrigerating apparatus comprising: a heating amount control means for controlling the changing speed of the heating upper limit capacity of the heating device according to the changing amount and the changing speed of the cold water temperature. 2. When the concentration of the solution is high or the amount of the refrigerant is large, and when the rate of rise of the cold water temperature in the cold water pipe is rapid, the rate of decrease of the heating upper limit value of the heating device is increased, If the rate of change of the cold water temperature changes below a certain value, delay the rate of decrease of the heating upper limit value, and further, when the concentration of the solution is low or when the liquid amount of the refrigerant is low, the decrease of the cold water temperature 2. The absorption refrigerating apparatus according to claim 1, wherein the increase rate of the heating upper limit value is increased when the temperature is abrupt, and the increase of the heating upper limit value is delayed when the heating upper limit value changes slower than a certain value.