JPH061136B2 - Absorption refrigerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a machine such as an absorption refrigerator, an absorption heat pump, and an absorption chiller-heater (hereinafter referred to as an absorption refrigerator), and particularly to an absorption liquid in a refrigerant. The present invention relates to an absorption refrigerating machine which is provided with a mechanism for measuring the degree of mixing of the refrigerant and is configured to blow the refrigerant before the degree of mixing of the absorbing liquid becomes too large.

(B) Conventional technology In an absorption refrigerator, when the absorption liquid in the generator is boiled to separate the refrigerant, small droplets of the absorption liquid mix into the separated refrigerant, and this mixing functions as an evaporator. This is one of the causes of the deterioration of the operating efficiency of the absorption refrigerating machine.
Therefore, in the absorption refrigerator, it is necessary to measure the degree of mixing of the absorbing liquid in the refrigerant and blow the refrigerant before the degree of mixing becomes excessive.

And as a conventional technique of this refrigerant blow, when the operation efficiency of the absorption refrigerator is significantly lowered, the operation is stopped and the refrigerant liquid in the machine is taken out, and the specific gravity of this refrigerant liquid is measured, and the degree of mixing of the absorbing liquid is large If too much, a manual means of blowing the refrigerant liquid into the absorbing liquid is known. Further, means for measuring the degree of mixing of the absorption liquid by detecting the electric conductivity of the liquid in the refrigerant liquid reservoir built in the evaporator, and blowing the refrigerant liquid into the absorption liquid based on the measurement result (for example, Japanese Patent Publication No. 1498
No. 9) is conventionally known.

(C) Problems to be solved by the invention In the conventional manual method, if the work is complicated and the cause of the decrease in operating efficiency is elsewhere, measure the degree of mixing of the absorbing liquid. There is a drawback that the work itself is wasted. Further, in the conventional means for blowing the refrigerant liquid by the measurement result of the electric conductivity, since the electric conductivity greatly changes when the rust or fine metal pieces are contained in the refrigerant even in a very small amount (in other words, Due to the large noise in the measurement), the reliability of the measurement is lacking, and as a result, the refrigerant is unnecessarily blown and the operating efficiency is rather lowered.

In view of the problems of these conventional techniques, the present invention aims to provide an absorption refrigerator that can easily and correctly know the degree of mixing of the absorbing liquid in the refrigerant, and can accurately prevent a decrease in operating efficiency. Is.

(D) Means for Solving Problems The present invention, as a means for solving the problems of the conventional technology, corresponds to a pressure detector that senses the internal pressure of the evaporator, and a pressure detected by this pressure detector. A calculator that calculates the evaporation temperature of the pure refrigerant liquid, a temperature detector that detects the evaporation temperature of the refrigerant in the evaporator, and an evaporator that uses the difference between the temperature detected by this temperature detector and the temperature calculated by the calculator. Judgment device that judges the degree of absorbing liquid mixed in the refrigerant liquid of the container and outputs a signal when the said amount reaches a predetermined value, a pipe line from the evaporator to the absorber and this pipe line The on-off valve is equipped with
(EN) An absorption refrigerating machine capable of easily and accurately determining the degree of mixing of an absorbing liquid in a refrigerant liquid and reliably preventing a decrease in operating efficiency.

(E) Function The means according to the present invention has less noise in measurement as compared with the conventional means for knowing the degree of mixing of the absorbing liquid in the refrigerant (hereinafter referred to as “mixing degree”) by measuring the electric conductivity. The function of properly refrigerating the refrigerant based on highly reliable measurement results before the operating efficiency of the absorption chiller significantly decreases due to excessive contamination. have. Therefore, it is possible to accurately prevent a decrease in operating efficiency.

(F) Example FIG. 1 shows an absorption refrigerator according to the present invention (hereinafter referred to as "this machine").
It is a schematic structure explanatory view showing one Example. In Fig. 1, (1) is a high temperature generator, (2) is a low temperature generator, (3) is a condenser, (4) is an evaporator, (5) is an absorber, and (6) is low temperature solution heat exchange. Vessel, (7) high temperature solution heat exchanger, (8) refrigerant pump,
(9) is a pump for absorbing liquid, and these devices include pipes (10), (10 ') through which the refrigerant flows, pipes (11) through which the refrigerant liquid flows, and pipes (12) and (12') through which the refrigerant liquid flows. ), Absorption liquid flow tubes (13), (13 '),
(14), (14 '), (15), and (15') are connected to form a circulation path for the refrigerant [water] and the absorbing liquid [lithium bromide aqueous solution].

(16) is the combustion heating chamber of the high temperature generator (1), (17) is the low temperature generator
(2) heater, (18) heat exchanger of evaporator (4), (19) and
(20) is a heat exchanger of the absorber (5) and the condenser (3) respectively, (21) is a pipe with a valve (V ') for supplying fuel to the combustion heating chamber (16), (22) , (22) ... are the tubes through which the combustion gas flows, (23), (2
3 ') is a pipe through which a refrigerant body such as cold water or cold air flows when the machine is used as a refrigerator, and a low temperature heat source fluid such as waste hot water or waste steam is used when the machine is used as a heat pump. , (24), (24 '), and (24'') are used when a cooling fluid such as cooling water or cooling air is used when the unit is used as a refrigerator, and when the unit is used as a heat pump. Is a pipe through which a warm medium such as warm water or warm air flows.

(25) and (26) are the refrigerant reservoirs of the condenser (3) and the evaporator (4) respectively, and (27) and (28) are the absorber reservoir of the absorber (5) and the low temperature generator (2) respectively. Is. (R) is a liquid level relay of the refrigerant liquid reservoir (26), and this relay suppresses the start / stop of the pump (8).

(S ₁ ) is a pressure detector that senses the internal pressure of the evaporator (4),
(S ₂ ) is a temperature detector for sensing the temperature of the refrigerant liquid in the refrigerant liquid reservoir (26) of the evaporator (4), and (C ₁ ) is a pressure detector (S ₁ ).
An arithmetic unit that receives the signal from the detector and calculates the evaporation temperature (saturation temperature) of pure refrigerant corresponding to the detected pressure of this detector,
(C ₂ ) receives signals from the calculator (C ₁ ) and the temperature detector (S ₂ ), calculates the difference between the sensed temperature of this detector and the calculated temperature of the calculator (C ₁ ), and A judging device for judging the degree of mixing of the absorbing liquid in the refrigerant (mixing ratio) based on this difference. The judging device and the computing device (C ₁ ) have a microprocessor unit and other computers built therein. That is, this machine has a mixing degree measuring mechanism including detectors (S ₁ ), (S ₂ ), a computing unit (C ₁ ) and a judging unit (C ₂ ).

Further, (29) is an absorption liquid reservoir (27) for the refrigerant liquid in the refrigerant liquid reservoir (26).
It is a pipe for flowing down to, and this pipe is equipped with an on-off valve (V). The switching of the opening / closing valve (V) is performed by the signal of the measuring mechanism described above.

Next, an example of the operation of the machine configured as described above will be described in the second
This will be described with reference to the drawings. Note that FIG. 2 is a Duhring diagram showing an example of the operation of this machine using water as a refrigerant and an aqueous lithium bromide solution as an absorbing liquid.

Now, when the internal pressure of the evaporator (4), that is, the pressure detected by the pressure detector (S ₁ ) is pmmHg during the operation of this machine, as shown in FIG. 2 (0), pure refrigerant in the evaporator (4) is obtained. Has an evaporation temperature of t ° C. The arithmetic unit (C ₁ ) in which the relational expression between the pure refrigerant evaporation temperature [saturation temperature] and the pressure [saturation vapor pressure] is programmed in advance receives the signal from the pressure detector (S ₁ ) Calculate t ° C.

In this case, when almost no absorption liquid is mixed in the refrigerant, the temperature of the refrigerant evaporated in the evaporator (4) is about t ° C.
Therefore, the temperature sensed by the temperature detector (S ₂ ) is also about t ° C. Then, the judging device (C ₂ ) which receives the signals from the temperature detector (S ₂ ) and the computing device (C ₁ ) detects that the difference between the actual temperature of the evaporated refrigerant and the calculated temperature is close to zero. And the evaporator
(4) It is judged that almost no absorbing liquid is mixed in the refrigerant inside. That is, the measuring mechanism measures the mixing degree to be almost zero.

Further, in this case, when a large amount of the absorbing liquid is mixed in the refrigerant separated by the high temperature generator (1) and the low temperature generator (2) for some reason, the evaporation temperature of this refrigerant is higher than the evaporation temperature of the pure refrigerant. Will also be higher. For example, the evaporation temperature of this refrigerant is t '° C.
If so, the temperature sensed by the temperature detector (S ₂ ) is also approximately t ′ ° C., and the discriminator (C ₂ ) shows that the difference between the actual temperature of the evaporated refrigerant and the calculated temperature is approximately [t′-t. ] It was detected that the temperature was in ° C, and the concentration of the absorbent in this refrigerant was approximately a% [Fig. 2
See (a)]. That is, the degree of mixing is measured to be approximately a%.

When the temperature detector (S ₂₎ the difference between the calculated temperature of the sensed temperature referred Kaere if the actual evaporation temperature of the refrigerant calculator (C ₁₎ of equal to or larger than the upper limit set value (for example, 2 ° C.), on-off valve ( V)
Is switched from closed to open, and the refrigerant liquid in the refrigerant liquid reservoir (25) is blown into the absorbing liquid in the absorbing liquid reservoir (27). If the difference between the sensed temperature and the calculated temperature is within the safety set value (for example, 2 ° C.), the opening / closing valve (V) is not opened / closed and normal operation is continued. Further, after the start of the refrigerant blow, when the difference between the sensed temperature and the calculated temperature shifts from the upper limit set value to the safety set value, the on-off valve (V) is closed again, the refrigerant blow is stopped, and the normal operation is performed. .

In addition, in this machine, the capacity of the refrigerant liquid reservoir (26) is
(3) is sufficiently large with respect to the amount of refrigerant liquid flowing down to the refrigerant liquid reservoir (26), and the temperature of the refrigerant liquid in the refrigerant liquid reservoir (26) is
It is assumed that the temperature of the non-evaporated refrigerant in (4) is almost equal. However, if the temperature of the refrigerant liquid in the refrigerant sump (26) rises to a non-negligible level due to the refrigerant liquid flowing down from the condenser (3), the function of making a judgment by subtracting the temperature rise is the judge (C _You just have to prepare for ₂ ).

In this way, the measuring mechanism equipped in this machine is designed to detect the evaporation temperature (evaporating temperature of the refrigerant) that changes depending on the degree of mixing of the absorbing liquid. Compared to the other, the measurement noise due to the influence of impurities other than the absorbent contained in the refrigerant is small and the measurement reliability is excellent. Then, when the operating efficiency of this machine is lowered due to the absorption liquid being mixed in the refrigerant, the cause can be easily and correctly known.

In addition, the machine is equipped with a reliable measuring mechanism signal to evaporate.
Since it is configured to blow the refrigerant liquid in (4) to the absorbent liquid in the absorber (5), it is included in the refrigerant liquid sprayed to the heat exchanger (18) of the evaporator (4). It is possible to prevent the amount of the absorbent from becoming excessive, and it is possible to maintain the degree of mixing below a predetermined value.
As a result, it is possible to accurately prevent the operating efficiency from being excessively lowered due to the mixing of the absorbing liquid into the refrigerant, and to keep the operating efficiency of the machine at a designed value.

(G) Effect of the Invention As described above, the absorption refrigerator according to the present invention calculates the evaporation temperature of the pure refrigerant corresponding to the internal pressure of the evaporator sensed by the pressure detector by the calculator, and determines the temperature and the temperature. An on-off valve provided in the conduit from the evaporator to the absorber, which determines the degree of the absorbing liquid mixed in the refrigerant liquid of the evaporator by the difference with the evaporation temperature of the refrigerant sensed by the detector. Since the changeover is performed by the signal from the determination device, it is possible to easily and correctly know the degree of mixing of the absorbing liquid in the refrigerant, as compared with the conventional absorption refrigerator.
Moreover, the refrigerant can be appropriately blown from the evaporator to the absorber, and the operating efficiency can be maintained almost as designed, which is of high practical value. It has a high practical value as it enables proper refrigerant blowing and keeps operating efficiency almost as designed.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view showing an embodiment of an absorption refrigerator according to the present invention, and FIG. 2 is a Duhring diagram showing an example of operation of the absorption refrigerator shown in FIG. (1) ... High temperature generator, (2) ... Low temperature generator, (3) ... Condenser, (4)
… Evaporator, (5)… Absorber, (8)… Pump, (12), (12 ′)…
Tube, (26) ... Refrigerant fluid reservoir, (27) ... Absorption fluid reservoir, (29) ... Pipe,
(C ₁ ) ... arithmetic unit, (C ₂ ) ... judging device, (S ₁ ) ... pressure detector, (S ₂ ) ... temperature detector, (V) ... on-off valve.

Claims (1)

[Claims] 1. A pressure detector for detecting the internal pressure of an evaporator, a calculator for calculating the evaporation temperature of pure refrigerant liquid corresponding to the pressure detected by the pressure detector, and an evaporation temperature of the refrigerant in the evaporator. Temperature detector, the degree of the absorbing liquid mixed in the refrigerant liquid of the evaporator is determined by the difference between the temperature sensed by the temperature detector and the temperature calculated by the calculator, and the degree reaches a predetermined value. A determination device that outputs a signal when it does, a pipeline from the evaporator to the absorber, and an opening / closing valve provided in this pipeline are provided, and switching of opening / closing of this opening / closing valve is performed by the signal of the determination device. Absorption refrigerator.