JP4315855B2 - Absorption refrigerator - Google Patents

Description

  The present invention relates to an absorption refrigerator that uses exhaust heat supplied from other equipment as a heat source of a regenerator that evaporates and separates a refrigerant by heating an absorption liquid.

  As this type of absorption refrigerator, for example, as shown in FIG. 3, the absorbent is heated and boiled to evaporate and separate the refrigerant sent to the evaporator 6, and as a regenerator for concentrating and regenerating the absorbent, the gas burner 1A Others such as a high-temperature regenerator 1 using the combustion heat generated in the heat source as a heating source for the absorption liquid, a low-temperature regenerator 2 using the refrigerant vapor supplied from the high-temperature regenerator 1 as a heating source for the absorption liquid, and a cogeneration system An absorption refrigerator 100X including a waste heat regenerator 3 that uses a waste heat fluid supplied from the above facility as a heating source is well known (see, for example, Patent Document 1).

  In the figure, 4 is a condenser arranged in parallel with the low-temperature regenerator 2 so that refrigerant vapor evaporated and separated from the absorbent in the low-temperature regenerator 2 can flow in, and 5 is evaporated from the absorbent in the exhaust heat regenerator 3. An exhaust heat condenser arranged in parallel with the exhaust heat regenerator 3 so that the separated refrigerant vapor can flow in; an absorber arranged in parallel with the evaporator 6 so that the refrigerant vapor evaporated in the evaporator 6 can flow in; 8 is a low-temperature heat exchanger, 9 is a high-temperature heat exchanger, 10 is a refrigerant pump, 11 and 12 are absorption liquid pumps, 13 is a flow control valve composed of a three-way valve, 14 to 17 are on-off valves, and 18 to 23 are absorption liquids. Pipes 24 to 29 are refrigerant pipes, 30 is a waste heat fluid supply pipe, 31 is a bypass pipe, 32 is a cold / hot water pipe, 33 is a cooling water pipe, 34 is a pressure equalizing pipe, and are connected as shown in FIG. The water cooled / heated to a predetermined temperature through the tube wall of the heat transfer tube 6A installed in the evaporator 6 Through the pipe 32 is circulated and supplied can be configured to the heat load (not shown).

In the absorption refrigerator 100X having the above-described configuration, combustion heat generated when natural gas or the like is burned by the gas burner 1A and exhaust heat supplied from other facilities such as a co-generation system via the exhaust heat fluid supply pipe 30. Since the absorbing liquid is heated and boiled using the fluid as a heat source, the thermal efficiency is high. Therefore, there is a merit that it is resource saving and the amount of carbon dioxide emission can be reduced.
JP-A-8-54153

  However, in the absorption refrigerator disclosed in Patent Document 1, when the heat load is small, the flow control of the exhaust heat fluid supplied from other equipment such as a co-generation system and flowing into the exhaust heat regenerator is performed. If it becomes impossible to reduce the amount of supply to the exhaust heat regenerator, b) the temperature of the chilled water supplied by cooling with the evaporator is too low, b) even if the operation of the absorption pump is stopped Since the exhaust heat regenerator does not become empty, the absorption liquid remaining in the exhaust heat regenerator continues to be heated by the exhaust heat fluid, resulting in excessive concentration of the absorption liquid and crystallization. It was.

  Therefore, even if the flow control of the exhaust heat fluid becomes impossible and the heat regeneration action on the absorbing liquid is excessively performed, it will not be impossible to operate due to an abnormal decrease in the temperature of the cold water, and the absorbing liquid will not crystallize. It was necessary to do it, and it was a problem to be solved.

In order to solve the above problems , the present invention
A dilute absorption liquid in which the refrigerant vapor from the evaporator is absorbed by the absorber is sent out by the absorption liquid pump, and the heat transfer pipe (that is, the exhaust heat transfer pipe) that circulates the exhaust heat fluid supplied from other equipment is placed in the middle section. Discharge port in which the concentrated absorption liquid obtained by spraying the absorption liquid from above the exhaust heat transfer pipe of the provided exhaust heat regenerator and evaporating and condensing the refrigerant is provided below the exhaust heat transfer pipe. And spray from above the cooling water pipe in the absorber,
The refrigerant evaporated in the exhaust heat regenerator is converted into a refrigerant liquid condensed by the cooling water pipe in the exhaust heat condenser, and the heat transfer pipe (that is, the load transfer pipe) that circulates the cooling fluid (that is, the load fluid) that is applied to the cooling load. By putting the refrigerant vapor evaporated by spraying the refrigerant liquid from above the load heat transfer tube of the evaporator provided with the heat pipe in the middle part, into the absorber,
In the absorption refrigerator characterized by providing a configuration for cooling the load fluid,
When the supply amount of the exhaust heat fluid supplied to the exhaust heat regenerator cannot be reduced, the operation of the absorption liquid pump is stopped or the rotation speed of the pump is reduced. (I.e., by reducing the pump operation), a control means is provided for controlling so that the upper surface of the concentrated absorbent in the exhaust heat regenerator is positioned below the exhaust heat transfer tube. An absorption refrigerator and
In the absorption refrigerator described above, when the temperature of the load fluid discharged from the load heat transfer tube is lower than a set temperature, the control means performs the pump operation stoppage. An absorption refrigerator is provided .

  In the absorption refrigerator of the present invention, when it becomes impossible to reduce the supply amount of the exhaust heat fluid to the heat transfer pipe in the exhaust heat regenerator, the operation of the absorption liquid pump is stopped or the rotation speed is reduced, and the absorber It is possible to limit the transport amount of the absorbing liquid from the waste heat regenerator.

  Therefore, when the cooling load is small and the temperature of the chilled water that is circulated and cooled by the evaporator drops abnormally, the liquid level of the absorbed liquid is lower than the heat transfer tube provided in the middle stage of the exhaust heat regenerator. Therefore, by stopping the operation of the absorption liquid pump or reducing the number of rotations to limit the amount of absorption liquid transported from the absorber to the exhaust heat regenerator, the absorption liquid can be absorbed by the exhaust heat fluid in the exhaust heat regenerator. Heating can be eliminated or reduced.

  For this reason, generation of refrigerant vapor in the exhaust heat regenerator and concentration / regeneration of the absorption liquid are eliminated or reduced, so that the temperature of the chilled water supplied by cooling with the evaporator may be abnormally decreased. You do n’t have to.

  In an absorption refrigerator equipped with an exhaust heat regenerator in which exhaust heat fluid supplied from other equipment is used as a heat source for heating the absorption liquid that has absorbed the refrigerant and evaporating and separating the refrigerant to concentrate and regenerate the absorption liquid. In the middle part of the heat regenerator, there is provided a heat transfer tube through which the exhaust heat fluid flows, an absorption liquid spreader is provided above the heat transfer tube, an absorption liquid discharge port is provided below, and the heat regenerator is cooled by the refrigerant evaporated by the evaporator. When the temperature of the chilled water discharged from the evaporator drops below the set temperature, it is judged that the operation to reduce the supply amount of exhaust heat fluid into the heat transfer tube is impossible, and the operation of the absorption pump is stopped or the rotation speed is reduced. An absorption refrigerating machine provided with a control means capable of limiting the amount of absorption liquid transported from the absorber to the exhaust heat regenerator.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. The absorption refrigerator 100 of the present invention illustrated in FIG. 1 can absorb cold water or hot water to a load (not shown) by using water as a refrigerant and an aqueous lithium bromide (LiBr) solution as an absorbent. It is a refrigerator. For ease of understanding, the same reference numerals are given to the portions having the same functions as those described in FIG. 3 in FIG.

The absorption chiller 100 of the present invention illustrated in FIG. 1 is different from the absorption chiller 100X shown in FIG. 3 in the configuration of the exhaust heat regenerator 3. That is, in the absorption refrigerator 100X shown in FIG. 3, an absorption liquid discharge port 3A is provided in the middle portion of the side wall of the exhaust heat regenerator 3, and one end of the absorption liquid pipe 19 is connected to the discharge port 3A. The absorption liquid of the exhaust heat regenerator 3 located higher than the discharge port 3A is provided so as to be transported to the high temperature regenerator 1 by the operation of the absorption liquid pump 12 interposed in the absorption liquid pipe 19, and is illustrated in FIG. In the absorption refrigerator 100 of the present invention, the absorption liquid discharge port 3A is provided at the bottom of the exhaust heat regenerator 3, and one end of the absorption liquid pipe 19 is connected thereto. Here, the above-mentioned absorption liquid pump 12 corresponds to the second absorption liquid pump in the above [Means for Solving the Problems].

  And in the absorption refrigerator 100X shown in FIG. 3, the heat transfer pipe 3B in the exhaust heat regenerator 3 to which the exhaust heat fluid supply pipe 30 is connected at both ends is shifted to the bottom side of the exhaust heat regenerator 3, That is, it is also installed at a portion lower than the discharge port 3A of the absorbing liquid provided in the middle stage of the side wall. In the absorption refrigerator 100 of the present invention illustrated in FIG. 1, the heat transfer tube 3B is the middle stage of the exhaust heat regenerator 3. It is installed in a part, that is, so that the whole is located above the discharge port 3A of the absorbing liquid.

Further, in the absorption refrigerator 100 of the present invention, the spreader 3C is installed above the heat transfer tube 3B, and one end of the absorption liquid pipe 18 is connected to the spreader 3C, and the absorption liquid interposed in the absorption liquid pipe 18 By the operation of the pump 11, the rare absorbent in the absorber 7 whose concentration has been reduced by absorbing the refrigerant is configured to be sprayed on the heat transfer tube 3B. Here, the absorption liquid pump 11 corresponds to the first absorption liquid pump in the above [Means for Solving the Problems].

  In addition, a temperature sensor 35 is provided on the outlet side of the evaporator 6 in the cold / hot water pipe 32 to exchange heat with the refrigerant through the tube wall of the heat transfer pipe 6A in the evaporator 6 and is cooled by latent heat when the refrigerant evaporates. Thus, the temperature of the cold / hot water discharged from the evaporator 6 can be measured. A controller 36 for controlling the gas burner 1 </ b> A, the refrigerant pump 10, the absorption liquid pumps 11 and 12, the flow rate control valve 13 and the like based on the temperature of the cold / hot water measured by the temperature sensor 35 is also provided.

  In the absorption refrigerator 100 having the above-described configuration, the cooling water is allowed to flow through the cooling water pipe 33 with the on-off valves 14 to 17 being closed, and natural gas or the like is combusted by the gas burner 1A, and the exhaust heat fluid supply pipe 30 is used. The absorber pump 11 is operated while flowing the exhaust heat fluid such as high-temperature / high-pressure steam or high-temperature water supplied from the co-generation system to the heat transfer tube 3B provided in the exhaust heat regenerator 3, and the absorber When the absorption liquid accumulated in the absorption liquid reservoir 7 is spread on the heat transfer tube 3B from the spreader 3C, the refrigerant vapor evaporated from the absorption liquid is separated from the refrigerant vapor, and the absorption liquid has a high concentration. The liquid is obtained in the high temperature regenerator 1 and the exhaust heat regenerator 3.

  The high-temperature refrigerant vapor generated in the high-temperature regenerator 1 enters the low-temperature regenerator 2 through the refrigerant pipe 24, is concentrated in the high-temperature regenerator 1, and passes through the high-temperature heat exchanger 9 through the high-temperature regenerator 1. The absorption liquid that has entered the regenerator 2 is heated and condensed by heat dissipation, and then enters the condenser 4.

  Further, the refrigerant vapor separated from the absorption liquid by heating in the low temperature regenerator 2 enters the condenser 4, is heat-exchanged with the cooling water flowing in the cooling water pipe 33 to be condensed and liquefied, and is condensed and supplied from the refrigerant pipe 24. The refrigerant enters the evaporator 6 through the refrigerant pipe 26 together with the refrigerant.

  The high-temperature refrigerant vapor generated in the exhaust heat regenerator 3 also enters the exhaust heat condenser 5 and exchanges heat with the cooling water flowing in the cooling water pipe 33 to be condensed and liquefied. to go into.

  The refrigerant liquid that has entered the evaporator 6 and accumulated in the refrigerant liquid reservoir is sprayed by the refrigerant pump 10 on the heat transfer pipe 6A to which the cold / hot water pipe 32 is connected, and exchanges heat with water that is circulated and supplied through the cold / hot water pipe 32. Then, it evaporates and cools the water flowing inside the heat transfer tube 6A.

  Then, the refrigerant evaporated by the evaporator 6 enters the absorber 7 and is heated by the low-temperature regenerator 2 to evaporate and separate the refrigerant. By the absorption liquid regenerated by increasing the concentration of the absorption liquid, that is, the absorption liquid pipe 21. It is supplied via the low-temperature heat exchanger 8 and is absorbed by the concentrated absorbent dispersed from above.

  Absorbing liquid whose concentration has been reduced by absorbing the refrigerant in the absorber 7, that is, the rare absorbing liquid, is transported to the exhaust heat regenerator 3 via the low-temperature heat exchanger 8 by the operation of the absorbing liquid pump 11, and spreader 3 </ b> C. The heat is then sprayed onto the heat transfer pipe 3B and heated by exchanging heat with the exhaust heat fluid supplied from the exhaust heat fluid supply pipe 30 as described above, and concentrated by evaporating and separating the refrigerant.

  When the operation is performed as described above, the cold water cooled by the heat of vaporization of the refrigerant in the heat transfer pipe 6A in the evaporator 6 can be circulated and supplied to a heat load (not shown) via the cold / hot water pipe 32. You can drive.

  The supply of the exhaust heat fluid from the exhaust heat fluid supply pipe 30 to the heat transfer pipe 3B is prioritized over the combustion of natural gas or the like in the gas burner 1A. That is, the controller 36 first controls the flow rate control valve 13 so that the temperature of the cold / hot water measured by the temperature sensor 35 is lowered to a predetermined set temperature, for example, 7 ° C., and the exhaust heat fluid flowing through the heat transfer tube 3B. Even when the amount is maximized, when the temperature of the cold / hot water measured by the temperature sensor 35 does not drop to the set temperature of 7 ° C., the absorption liquid is heated by the gas burner 1A, and the high-temperature regenerator 1 generates refrigerant vapor. The concentration of the absorbent is regenerated, and the temperature of the chilled / hot water cooled by the evaporator 6 and discharged to the chilled / hot water pipe 32 is controlled to a preset temperature of 7 ° C., and the heating amount by the gas burner 1A is minimized. If the temperature of the cold / hot water measured by the temperature sensor 35 does not rise to the set temperature of 7 ° C., the heating by the gas burner 1A is stopped, and the flow rate control valve 13 is further controlled to supply the exhaust heat fluid to the heat transfer tube 3B. Squeeze Cooled in Hatsuki 6 the temperature of the hot and cold water to be discharged to the cold and hot water pipe 32 is configured to be 7 ° C. set temperature.

  In the absorption refrigerator 100 of the present invention, the absorption liquid discharge port 3A of the exhaust heat regenerator 3 is provided at the bottom portion as described above. Therefore, when the operation of the absorption liquid pump 11 is stopped, The heat regenerator 3 becomes empty. That is, while the combustion of the gas burner 1A is stopped, the operation of the absorption liquid pump 12 is stopped by the controller 36. Therefore, the absorption in the exhaust heat regenerator 3 is caused by the pressure difference between the exhaust heat regenerator 3 and the absorber 7. The liquid is returned to the absorber 7 through the absorption liquid pipes 19, 22, and 21, and the absorption liquid pump 12 is also operated by the controller 36 during the combustion of the gas burner 1 </ b> A, so that the absorption liquid in the exhaust heat regenerator 3 is It is sent to the high-temperature and high-pressure regenerator 1 through the absorption liquid pipe 19.

  Therefore, when the flow rate control valve 13 becomes unstable and the flow rate of the exhaust heat fluid supplied from the exhaust heat fluid supply pipe 30 to the heat transfer pipe 3B of the exhaust heat regenerator 3 cannot be restricted, the operation of the absorbent pump 11 is stopped. Or the number of rotations is reduced, and the amount of absorption liquid transported from the absorber 7 to the exhaust heat regenerator 3 is limited so that the liquid level of the absorption liquid in the exhaust heat regenerator 3 is below the heat transfer pipe 3B. As a result, even if exhaust heat fluid such as high-temperature / high-pressure steam and high-temperature water supplied from a co-generation system continues to be supplied from the exhaust heat fluid supply pipe 30 to the heat transfer pipe 3B, the exhaust heat regenerator 3 absorbs it. Since the liquid is not heated or the heating amount is suppressed, generation of refrigerant vapor in the exhaust heat regenerator 3 can be eliminated, and the absorption liquid supplied to the absorber 7 can be prevented from crystallizing.

  Therefore, the operation of the absorption liquid pump 11 is configured to be controlled by the controller 36 as shown in FIG. 2A based on the temperature of the cold / hot water measured by the temperature sensor 35, for example.

  That is, the controller 36 absorbs the absorbing liquid pump 11 when the temperature of the cold / hot water measured by the temperature sensor 35 is, for example, 4.5 ° C. or lower and while the temperature rises from 4.5 ° C. or lower to 5.5 ° C. Is configured to output a necessary control signal for operating the absorption liquid pump 11 when the temperature is 5.5 ° C. or higher and when the temperature drops from 5.5 ° C. or higher to 4.5 ° C. Has been.

  Therefore, in the absorption refrigerator 100 of the present invention, the flow rate control valve 13 becomes unstable, and the flow rate of the exhaust heat fluid supplied from the exhaust heat fluid supply pipe 30 to the heat transfer pipe 3B of the exhaust heat regenerator 3 cannot be limited. Even if the heating by the gas burner 1A is stopped, the temperature of the cold / hot water cooled by the heat transfer pipe 6A of the evaporator 6 and discharged to the cold / hot water pipe 32 falls below 4.5 ° C., and the temperature sensor 35 measures it. The operation of the pump 11 is stopped by the controller 36.

  Therefore, the exhaust heat regenerator 3 becomes empty, and exhaust heat fluid such as high-temperature and high-pressure steam and high-temperature water supplied from a cogeneration system or the like continues to be supplied from the exhaust heat fluid supply pipe 30 to the heat transfer pipe 3B. However, since the absorption liquid is no longer heated in the exhaust heat regenerator 3, the refrigerant vapor is not generated in the exhaust heat regenerator 3, and the absorption liquid is not excessively concentrated and crystallized.

  As shown in FIG. 2 (B) by the controller 36, for example, when the temperature of the cold / hot water measured by the temperature sensor 35 is 4.5 ° C. or less, the absorbent pump 11 When the electric power frequency applied to the electric motor to be driven is 0 Hz and the temperature of the cold / hot water is 5.5 ° C. or higher, the specified maximum frequency is set to 60 Hz, for example, and the temperature of the cold / hot water is 4.5 ° C. and 5.5 ° C. When it is in between, the power frequency applied to the electric motor may be selected as being proportional to the temperature of the cold / hot water, and the rotation may be controlled in this way.

  In the absorption refrigerator 100 of the present invention configured as described above, when the on-off valves 14 to 17 are opened and the natural gas or the like is burned by the gas burner 1A to heat the absorption liquid in the high-temperature regenerator 1 and boil it. Then, it is evaporated and separated from the absorption liquid, flows into the absorber 7 through the refrigerant tubes 24 and 25, and further, the refrigerant vapor entering the evaporator 6 touches the tube wall of the heat transfer tube 6A and condenses. Since the water flowing in the heat transfer tube 6A is heated mainly by the heat of condensation of the refrigerant, a heating operation such as heating can be performed by circulating and supplying the heated water to the load.

  By the way, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit described in the claims.

  For example, a rare absorbent whose concentration has been reduced by absorbing the refrigerant in the absorber 7 is first transported to the exhaust heat regenerator 3 and concentrated, and the concentrated absorbent is transported to the low temperature regenerator 2 and concentrated. Finally, an absorption liquid pipe may be piped so as to be transported to the high temperature regenerator 1 and concentrated, or a rare absorption liquid whose concentration has been reduced by absorbing the refrigerant in the absorber 7 is reduced with the high temperature regenerator 1. The absorption liquid pipe is piped so as to be branched and transported to the exhaust heat regenerator 3, and the absorbent concentrated in the high temperature regenerator 1 and the exhaust heat regenerator 3 is transported to the low temperature regenerator 2 and concentrated. Also good.

  Further, the refrigerant pipe 29 in which the on-off valve 17 is interposed may be provided as in the absorption refrigerator 100X shown in FIG. 3, that is, between the downstream side of the refrigerant pump 10 and the absorber 7.

  Further, an absorption refrigerator that does not include the high-temperature regenerator 1 and the low-temperature regenerator 2 and is configured such that the absorption liquid circulates between the exhaust heat regenerator 3 and the absorber 7 may be used.

It is explanatory drawing of the absorption refrigerator of this invention. It is explanatory drawing which shows the example of control of an absorption liquid pump. It is explanatory drawing of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High temperature regenerator 2 Low temperature regenerator 3 Waste heat regenerator 3A (absorption liquid) discharge port 3B Heat transfer tube 3C Spreader 4 Condenser 5 Exhaust heat condenser 6 Evaporator 6A Heat transfer tube 7 Absorber 8 Low temperature heat exchanger 9 High-temperature heat exchanger 10 Refrigerant pump 11, 12 Absorption liquid pump 13 Flow control valve (three-way valve)
14-17 On-off valve 18-23 Absorption liquid pipe 24-29 Refrigerant pipe 30 Waste heat fluid supply pipe 31 Bypass pipe 32 Cold / hot water pipe 33 Cooling water pipe 34 Pressure equalizing pipe 35 Temperature sensor 36 Controller 100, 100X Absorption refrigerator

Claims (2)

A heat absorption tube (hereinafter referred to as an exhaust heat transfer tube) that sends out a diluted absorption liquid in which the refrigerant vapor from the evaporator is absorbed by the absorber by the first absorption liquid pump and distributes the exhaust heat fluid supplied from other equipment. In the exhaust heat regenerator of the exhaust heat regenerator provided in the middle stage, the absorption liquid, which has been condensed by evaporation of the refrigerant by evaporating the refrigerant from above the exhaust heat transfer tube, is provided below the exhaust heat transfer tube. A structure that is discharged from the outlet and sprayed from above the cooling water pipe in the absorber, and is sent to a high-temperature regenerator that heats the absorption liquid by using a combustion heat of fuel as a heating source by a second absorption liquid pump. ,
The refrigerant evaporated in the exhaust heat regenerator is made into a refrigerant liquid condensed by the cooling water pipe in the exhaust heat condenser 3, and a heat transfer pipe (hereinafter referred to as load fluid) that circulates a cooling fluid applied to a cooling load (hereinafter referred to as load fluid). The load fluid is cooled by introducing into the absorber the refrigerant vapor that has been evaporated by spraying the refrigerant liquid from above the load heat transfer pipe of the evaporator provided with a load heat transfer pipe in the middle stage. Configuration and
In the absorption refrigerator characterized by providing
When the supply amount of the exhaust heat fluid supplied to the exhaust heat regenerator cannot be reduced, the heating of the high temperature regenerator is stopped and the second absorption liquid pump is operated. The upper surface of the absorption liquid in the exhaust heat regenerator by stopping the operation of the first absorption liquid pump or reducing the number of rotations of the first absorption liquid pump (hereinafter referred to as pump operation stoppage). An absorption refrigeration machine comprising a control means for controlling so as to be positioned below the exhaust heat transfer tube . 2. The absorption chiller according to claim 1 , wherein when the temperature of the load fluid discharged from the load heat transfer tube is lower than a set temperature , the control means performs the pump operation stoppage .

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