JP3715157B2 - 2-stage double-effect absorption refrigerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-stage double-effect absorption refrigerator that uses a water refrigerant used for refrigeration and air conditioning and an aqueous salt solution as an absorbent, and particularly suitable for low-temperature use of about 3 ° C to -10 ° C. The present invention relates to a double effect absorption refrigerator.
[0002]
[Prior art]
The two-stage double effect absorption refrigerator includes a high temperature regenerator, a low temperature regenerator, a condenser, a first evaporator, a first absorber, a second evaporator, a second absorber, a liquid heat exchanger, a solution circulation pump, A refrigerant pump, solution spray pump, etc. are operatively connected to the pipe. When the diluted solution of the first or second absorber is concentrated, it is concentrated in a double effect absorption refrigeration cycle of a high temperature regenerator and a low temperature regenerator. ing. Here, the second absorber operates at a lower pressure than the first absorber, and the second evaporator produces cold water or brine that is cooler than the first evaporator. A two-stage double-effect absorption refrigeration cycle capable of generating a low temperature is described in, for example, Japanese Patent Application Laid-Open No. 7-139844. This is a two-stage double-effect absorption cycle having a second evaporator and a second absorber, and cooling the second absorber with a low-temperature medium generated by the first evaporator. In order to prevent the water refrigerant from freezing in the second evaporator, a mixed refrigerant in which an absorbing liquid is mixed is used. For example, Japanese Patent Publication No. 58-15703, Japanese Patent Application Laid-Open No. 7-139844, Japanese Patent Application Laid-Open No. 55-162565, Japanese Patent Application Laid-Open No. 55-162565 are disclosed as means for preventing freezing by mixing an absorbing solution into the refrigerant in the evaporator. JP-A-60-103268, JP-A-60-103269, and the like.
[0003]
[Problems to be solved by the invention]
In the above-described conventional two-stage double-effect absorption refrigerator, the arrangement relationship between the liquid reservoirs of the first absorber and the second absorber is not particularly described. Here, in the absorption refrigerator, when the liquid holding amount is increased, the refrigerant holding amount for adjusting the concentration of the absorbing liquid is increased, the volume of the refrigerant reservoir is increased, and the load response is increased. The nature is also reduced. In addition, an aqueous salt solution that is an absorbing solution, for example, a lithium bromide aqueous solution (LiBr aqueous solution), solidifies when cooled while concentrated to a high concentration. However, a cycle circulation configuration that can continue operation even in such a trouble is desired. ing.
[0004]
A first object of the present invention is to provide a two-stage double-effect absorption refrigerator that can reduce the size of the device and reduce the cost.
A second object of the present invention is to provide a two-stage double-effect absorption refrigerator that has good load responsiveness and can accelerate cycle stability.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the configuration of the two-stage double-effect absorption refrigerator according to the present invention includes a first evaporator, a first absorber, a second evaporator, a second absorber, and a solution circulation pump. In the two-stage double-effect absorption refrigerator that uses an aqueous salt solution that cools the second absorber with a cooling medium that is lower in temperature than the cooling medium that cools the first absorber, the liquid in the second absorber The reservoir is disposed above the liquid reservoir of the first absorber, and a liquid level detecting means is provided in the liquid reservoir of the second absorber, and the liquid level of the liquid reservoir of the second absorber is predetermined. When the following condition is reached, the solution circulation pump of the second absorber is stopped .
[0006]
In order to achieve the above object, another invention of a two-stage double-effect absorption refrigerator according to the present invention is such that the refrigerant of the second evaporator is a mixed refrigerant containing an absorbing liquid, and the concentration detection of the mixed refrigerant is performed. And a liquid refrigerant supply control means from the first evaporator, the liquid reservoir of the second absorber is disposed above the liquid reservoir of the first absorber, and the liquid of the second absorber A liquid level detecting means is provided in the reservoir, and the solution circulation pump of the second absorber is stopped when the liquid level of the liquid reservoir of the second absorber becomes below a predetermined level .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a system diagram of a first embodiment according to the two-stage double-effect absorption refrigerator of the present invention. The two-stage double effect absorption refrigerator includes a high temperature regenerator 1A, a low temperature low temperature regenerator 1B, a condenser 2, a first evaporator 3A, a second evaporator 3B, a first absorber 4A, a second absorber 4B, a liquid The heat exchangers 5A, 5B, and 5C, the solution spray pumps 6A and 6B, the solution circulation pump 6C, and the like are connected by piping to form a circulation path for the refrigerant and the absorbing liquid.
[0011]
The high temperature regenerator 1A is provided with a heat transfer surface HA for heating and boiling a diluted solution having a reduced concentration by absorbing refrigerant with a combustion gas such as city gas, exhaust gas, or steam, and the low temperature regenerator 1B. Is provided with a heat transfer surface HB for heating and boiling the solution using the latent heat of condensation of the refrigerant vapor generated in the high temperature regenerator 1A as a heat source. The refrigerant vapor generated in the high temperature regenerator 1 </ b> A heats the absorption liquid of the low temperature regenerator 1 </ b> B to be condensed and liquefied to become a liquid refrigerant, and is introduced into the condenser 2. Refrigerant vapor generated in the low-temperature regenerator 1B is also introduced into the condenser 2, cooled by cooling water CW flowing from the cooling tower or the like flowing in the heat transfer surface 32, and condensed and liquefied to become liquid refrigerant.
[0012]
The liquid refrigerant generated in the condenser 2 is introduced into the refrigerant liquid reservoir 8A of the first evaporator 3A via the refrigerant conduit 10. The introduced refrigerant liquid is sprayed and evaporated on the heat transfer pipe 31A by the refrigerant spray pump 7A, and the refrigerant vapor is guided to the first absorber 4A via the eliminator. Further, the heat exchanger tube 31A of the first evaporator 3A and the heat exchanger tube 30B of the second absorber 4B are circulated so that the second absorber 4B can be cooled by the cold medium having a low temperature generated by the first evaporator 3A. Thermally connected via a water pump 27. For this reason, the heat transfer tube 30B in the second absorber 4B is cooled by the latent heat of vaporization of the low-temperature refrigerant obtained in the first evaporator 3A.
[0013]
The liquid refrigerant in the refrigerant liquid reservoir 8A of the first evaporator 3A passes through the motor operated valve 18 which is an inflow control means by the refrigerant spray pump 7A, and the pump suction side of the mixed refrigerant spray pump 7B in the mixed refrigerant liquid reservoir 8B. To be introduced. By mixing the refrigerant with the absorbing liquid on the pump suction side of the mixed refrigerant spray pump 7B having a high flow rate, both media having a difference in concentration are quickly mixed to prevent corrosion and ice formation due to concentration cell formation. Yes.
[0014]
The mixed refrigerant in the mixed refrigerant liquid reservoir 8B is sprayed and evaporated on the heat transfer pipe 31B in the second evaporator 3B by the mixed refrigerant spray pump 7B to cool water (or brine) flowing in the heat transfer pipe 31B. To do. The absorption liquid concentration in the mixed refrigerant liquid reservoir 8B is detected and calculated by the concentration detector 24 to control the opening and closing of the motor-operated valve 18. Further, the mixed refrigerant amount in the mixed refrigerant liquid reservoir 8B is detected and calculated by the liquid level detecting means 28. If it is determined that the liquid holding amount is small even though it is at an appropriate concentration, the absorbing liquid is caused by some cause. Because it is a case of spillage and shortage,
(1) A warning is displayed to replenish the absorption liquid. Alternatively, the data is communicated to the maintenance company via the communication means. Thereby, the absorbing liquid is supplied to the mixed refrigerant liquid reservoir 8B. Or
(2) Absorbing liquid, for example, a solution pipe branched from the discharge side of the solution circulation pump 6A is connected to the pump suction side of the mixed refrigerant spray pump 7B, and a solution flow rate control means 34, a filter 35, and a copper ion removal means 36 are provided on the way. It arrange | positions and replenishes absorption liquid to the mixed refrigerant liquid reservoir 8B by introduce | transducing the absorption liquid of a cycle.
[0015]
As described above, the liquid level of the mixed refrigerant liquid reservoir 8B can be properly maintained and the mixed refrigerant concentration can be appropriately maintained, so that freezing of the refrigerant and idling of the mixed refrigerant spray pump 7B can be prevented, and safety is ensured. You can continue driving.
[0016]
On the other hand, the absorption liquid concentrated by generating the refrigerant vapor in the regenerators 1A and 1B becomes a low temperature through heat exchange with the dilute solution in the solution heat exchangers 5A and 5B. It is sent to the absorber 4A and is cooled by the coolant sprayed on the heat transfer tube 30A of the first absorber 4A by the solution spray pump 6A and flowing through the tube. Along with this, the absorbing liquid absorbs the refrigerant vapor evaporated in the first evaporator 3A and becomes thin. The thinned absorption liquid of the first absorber 4A flows down the liquid reservoir 25A, and is sent to the second absorber 4B via the solution conduit 14 and the low-temperature liquid heat exchanger 5C by the solution spray pump 6B, and the heat transfer tube It is sprayed onto 30B and cooled by the latent heat of vaporization of the refrigerant from the first evaporator 3A. Further, the refrigerant vapor from the second evaporator 3B is absorbed and diluted to become a further dilute solution, which flows down the liquid extraction means 29 arranged at the lower part of the tube group of the heat transfer tubes 30B, and at that time the noncondensable gas is removed. Get involved. Further, the dilute solution is sent by the solution circulation pump 6C to the regenerators 1A and 1B via the low temperature liquid heat exchanger 5C, the dilute solution conduit 13, and the solution heat exchangers 5B and 5A.
[0017]
As described above, the two-stage double-effect absorption refrigeration cycle is configured. However, in the present embodiment, the second absorber 4B is disposed at a position higher than the first absorber 4A, so the second absorber 3B. The liquid reservoir 25B is almost free of solution under the condition that the concentration of the absorbent in the cycle during the load operation is high. This
(1) The liquid reservoir that mainly holds the dilute solution can be used as the liquid reservoir 25A of the first absorber 4A. Since the concentration of the absorption liquid in the liquid reservoir 25A is an intermediate concentration higher than that of the solution generated in the second absorber 4B, the amount of refrigerant retained is smaller than that in the liquid reservoir 25B of the second absorber 4B. Tesumu. When the temperature of water (or brine) is low or the temperature of the cooling water CW is high, the cycle is shifted to the high concentration side to increase the amount of refrigerant stored in the refrigerant liquid reservoir 8A. At that time, the amount of liquid retained in the liquid reservoir 25A is reduced to a high concentration. Of course, since the concentration of the second absorber 4B is increased and the concentration in the liquid reservoir 25B is also increased, this amount of refrigerant is also stored in the refrigerant reservoir 8A.
[0018]
For this reason, the liquid amount of the liquid reservoir 25B of the second absorber 4B is small, and the refrigerant holding amount can be reduced. Therefore, it is possible to reduce the size of the device, improve the load responsiveness, and reduce the cost. further,
(2) The pump suction side of the liquid spray pump 6B installed below the liquid reservoir 25A of the first absorber and the pump suction side of the liquid spray pump 6C installed below the liquid reservoir 25B of the second absorber By connecting with the communication pipe 15, there is an effect that the liquid pump 6C can be prevented from idling and can be stably operated even when the liquid reservoir 25B of the second absorber has almost no solution.
[0019]
FIG. 2 is a system diagram of a second embodiment according to the two-stage double-effect absorption refrigerator of the present invention. The same components as those in the embodiment of FIG.
This embodiment is different from the embodiment of FIG. 1 in that the second evaporator and the second absorber are installed above the first evaporator and the first absorber.
According to the present embodiment, the installation area of the absorption refrigerator can be reduced.
[0020]
FIG. 3 is a system diagram of a third embodiment according to the two-stage double-effect absorption refrigerator of the present invention. The same components as those in the embodiment of FIG.
The present embodiment differs from the embodiment of FIG. 1 in that the liquid level detecting means 40 is disposed in the liquid reservoir 25B of the second absorber instead of the communication pipe 15 of FIG. Thus, the solution spray pump 6B is controlled.
According to this embodiment, the idling of the solution circulation pump 6C can be prevented and a stable operation can be performed.
[0021]
FIG. 4 is a system diagram of a fourth embodiment according to the two-stage double-effect absorption refrigerator of the present invention. The same components as those in the embodiment of FIG.
The present embodiment differs from the embodiment of FIG. 1 in that the liquid level detecting means 40 is disposed in the liquid reservoir 25B of the second absorber instead of the solution conduit 15 of FIG. When it is detected that the liquid circulation pump 6C has been detected, the solution circulation pump 6C is stopped.
According to this embodiment, the idling of the solution circulation pump 6C can be prevented and a stable operation can be performed.
[0022]
【The invention's effect】
As described above, according to the present invention, the liquid reservoir mainly holding the dilute solution can be used as the liquid reservoir of the first absorber, and the concentration can be held at an intermediate concentration. A refrigerant holding amount can be reduced according to the range, and therefore a two-stage double-effect absorption refrigerator that can reduce the size of the device and can reduce the cost can be provided.
In addition, according to the present invention, since the refrigerant holding amount can be reduced, it is possible to provide a two-stage double-effect absorption refrigerator that can improve load response and accelerate cycle stability.
[Brief description of the drawings]
FIG. 1 is a system diagram of a first embodiment according to the two-stage double-effect absorption refrigerator of the present invention.
FIG. 2 is a system diagram of a second embodiment according to the two-stage double-effect absorption refrigerator of the present invention.
FIG. 3 is a system diagram of a third embodiment according to the two-stage double-effect absorption refrigerator of the present invention.
FIG. 4 is a system diagram of a third embodiment according to the two-stage double-effect absorption refrigerator of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1A ... High temperature regenerator, 1B ... Low temperature regenerator 2 ... Condenser 3A ... 1st evaporator, 3B ... 2nd evaporator 4A ... 1st absorber, 4B ... 2nd absorber 5A ... High temperature liquid heat exchanger, 5B ... medium temperature liquid heat exchanger, 5C ... low temperature liquid heat exchanger 6A ... solution spray pump, 6B ... solution spray pump, 6C ... solution circulation pump 7A ... refrigerant spray pump, 7B ... mixed refrigerant spray pump 8A ... refrigerant reservoir, 8B ... mixed refrigerant reservoirs 10, 11 ... refrigerant conduit 12 ... concentrated solution conduit 13 ... dilute solution conduit 14 ... solution conduit 15 ... communication pipe 18 ... refrigerant flow rate control means 24 ... concentration detector 25A ... liquid reservoir of the first absorber 25B ... Second absorber liquid reservoir 27 ... Circulating water pump 28 ... Liquid level detector 29 ... Liquid flow extraction means 30A, 30B, 31A, 31B, 32 ... Heat transfer pipe 33 ... Pipe 34 ... Solution flow rate control means 35 ... Filter 36 ... Copper ion removal means 40 ... Liquid level inspection Vessels HA, HB ... heat transfer surfaces CW ... cooling water

Claims (2)

A first evaporator, a first absorber, a second evaporator, a second absorber, and a solution circulation pump are provided, and the second absorber is cooled by a cooling medium that is lower in temperature than the cooling medium that cools the first absorber. In a two-stage double-effect absorption refrigerator using an aqueous salt solution as an absorbent,
While disposing the liquid reservoir of the second absorber above the liquid reservoir of the first absorber ,
A liquid level detecting means is provided in the liquid reservoir of the second absorber, and the liquid circulation pump of the second absorber is stopped when the liquid level of the liquid reservoir of the second absorber becomes below a predetermined level. A featured two-stage double-effect absorption refrigerator. A first evaporator, a first absorber, a second evaporator, a second absorber, and a solution circulation pump are provided, and the second absorber is cooled by a cooling medium that is lower in temperature than the cooling medium that cools the first absorber. In a two-stage double-effect absorption refrigerator using an aqueous salt solution as an absorbent,
The refrigerant of the second evaporator is a mixed refrigerant containing an absorption liquid, and has concentration detecting means for the mixed refrigerant, liquid refrigerant supply control means from the first evaporator,
While disposing the liquid reservoir of the second absorber above the liquid reservoir of the first absorber ,
A liquid level detecting means is provided in the liquid reservoir of the second absorber, and the liquid circulation pump of the second absorber is stopped when the liquid level of the liquid reservoir of the second absorber becomes below a predetermined level. A featured two-stage double-effect absorption refrigerator.

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