JP4205896B2 - Absorption refrigerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an absorption refrigerator used as a heat source for air conditioning equipment such as buildings.
[0002]
[Prior art]
In an absorption refrigerator, an aqueous lithium bromide solution is generally used as an absorbing solution. Since an aqueous solution of lithium bromide is a highly corrosive solution, an inhibitor (corrosion inhibitor) is added, but corrosion proceeds particularly in a high temperature environment. In the corrosion by the absorbing liquid, hydrogen gas is generated from the reaction between the absorbing liquid and iron which is the material of the main body. Moreover, in the absorption refrigerator, since the whole apparatus is negative pressure from atmospheric pressure, a very small amount of air enters. The non-condensable gas mainly composed of hydrogen gas generated in the high-temperature regenerator first gathers in the condenser together with the refrigerant vapor. The refrigerant vapor flowing into the condenser is condensed on the surface of the heat transfer tube and falls as water droplets, but the non-condensable gas does not condense and stays around the heat transfer tube, thereby obstructing the flow of the refrigerant vapor.
[0003]
Some non-condensable gases are dissolved in the liquid refrigerant and sent to the evaporator. The noncondensable gas released in the evaporator flows into the absorber together with the refrigerant vapor. In the absorber, the refrigerant vapor is absorbed by the absorption liquid, but the non-condensable gas is not absorbed. Therefore, the refrigerant vapor stays and accumulates around the heat transfer tube to block the flow of the refrigerant vapor and inhibit heat exchange. Therefore, accumulation of non-condensable gas reduces the refrigeration performance of the absorption refrigerator. For this reason, the extraction apparatus for discharging | emitting noncondensable gas out of an apparatus is needed.
[0004]
Conventionally, as a bleeder, there are those disclosed in, for example, JP-A-7-120110, JP-A-9-203568, etc., and an ejector is driven using a part of the absorbing liquid, and a non-condensable gas together with refrigerant vapor (Prior art 1).
In addition, as described in JP-A-10-89814, JP-A-10-292959, and the like, there is also known an extraction device that performs extraction by arranging a discharge nozzle and a suction tube perpendicular to a heat transfer tube ( Prior art 2).
[0005]
[Problems to be solved by the invention]
As known from the prior art 1, in the case where the absorber is extracted using an ejector, an extraction pipe for guiding the extracted gas from the absorber to the ejector is required. In order to extract the non-condensable gas, the non-condensable gas is sucked together with the refrigerant vapor. Therefore, the refrigerant vapor flows many times as much as the non-condensable gas in the extraction pipe. Therefore, flow resistance is generated in the bleed piping, and a large pressure loss is generated between the absorber and the ejector. Since the absorber is normally a vacuum of about 1/100 atm, the pressure loss of the extraction pipe causes a large efficiency reduction for the extraction apparatus that creates a low-pressure environment and sucks the gas. Moreover, the ejector provided outside the absorber occupies a large space itself.
Moreover, in the prior art 2, since the discharge nozzle and the suction pipe are arranged perpendicular to the heat transfer pipe, the heat transfer pipe becomes an obstacle in the upper and lower parts in the absorber, and therefore the heat transfer pipe is arranged in the space of the obstacle part. There was no consideration for the inability to do so.
[0006]
An object of the present invention is to reduce the heat transfer tube comprising a discharge nozzle and a suction pipe thus failure of the bleed device and space saving, it is possible to miniaturize, unnecessary and pressure loss extract air pipe you bleed uncondensed gas It is an object of the present invention to provide an absorption refrigerator that can improve the extraction efficiency by reducing the size and reduce the size.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an absorption refrigerator according to the present invention is connected to an evaporator, an absorber having a heat transfer tube extending in a plurality of stages in the horizontal direction, a condenser, a regenerator, and a solution circulation pump. In an absorption refrigerator that constitutes an absorption refrigeration cycle and includes a gas-liquid separator that separates a solution and non-condensable gas, a discharge nozzle having a solution discharge port and a suction tube having a suction port opposed to the discharge port A bleed device having the same axis is provided in the absorber, the discharge nozzle and the suction pipe are arranged so as to extend in parallel between the heat transfer pipes, and the inlet side of the discharge nozzle is connected to the solution circulation pump. The absorber is connected to the flow path leading a part of the discharge solution and the outlet side of the suction pipe is connected to the flow path leading to the suction side of the solution circulation pump, and the solution is ejected from the discharge port of the discharge nozzle Around the discharge nozzle inside It is to bleed the uncondensed gas into the suction pipe with some refrigerant vapor.
A more preferable specific configuration example of the present invention is as follows.
(1) A vane for giving a swirling flow to the solution is provided in the discharge nozzle.
(2) In the above (1), the straight portion of the suction tube has a length that is at least four times the inner diameter of the suction tube.
(3) A part of the solution discharged from the solution circulation pump is cooled in the evaporator and then guided to the discharge nozzle of the extraction device.
(4) The absorber is composed of a low-pressure absorber and a high-pressure absorber, and an extraction device is provided in the low-pressure absorber.
(5) A solution driven ejector driven by a solution , an air storage tank for storing non-condensable gas, a valve connected to the air storage tank, and a water driven ejector driven by water , and discharging the solution driven ejector from the solution circulation pump A part of the solution is driven and driven , and the suction part of the solution-driven ejector is connected to the condenser, and the solution outflow part of the solution-driven ejector is connected to the gas-liquid separator. After placing the gas storage tank in the upper part, connecting the gas phase part of the gas-liquid separator and the gas storage tank, and after raising the pipe connected to the liquid phase part of the gas-liquid separator to a predetermined height , Connected to the suction side of the solution circulation pump or the absorber, and connected to the suction tank of the water-driven ejector driven by water with the storage tank through a valve, and the water outflow portion of the water-driven ejector Sucking Open to the outside of the refrigerator, said absorber in bleed the noncondensable gas guided to the condenser by the solution circulating pump, noncondensable gas in the gas storage tank through the solution driving ejector and the gas-liquid separator from the condenser And discharging the non-condensable gas to the outside with the water-driven ejector.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system diagram of a first embodiment according to the absorption refrigerator of the present invention, which is an example in which an aqueous lithium bromide solution is used as an absorption liquid.
The absorption refrigerator constitutes a double effect cycle with the evaporator 1, the absorber 2, the condenser 3, the low temperature regenerator 4, the high temperature regenerator 5, and the solution circulation pump 7 as main components. In addition, a refrigerant pump 6 for circulating and spraying water as a refrigerant, a low-temperature heat exchanger 8 for exchanging heat between solutions, and a high-temperature heat exchanger 9 are provided.
[0012]
A heat transfer tube 10 is disposed in the evaporator 1, cold water is allowed to flow inside the tube, and a refrigerant is scattered outside the tube. The evaporator 1 and the absorber 2 have substantially the same pressure of about 1/100 atm. Since the evaporator 1 has a low pressure, the refrigerant evaporates. By taking away the latent heat of evaporation at this time from the cold water in the heat transfer tube 10, the cold water becomes cooler. The refrigerant evaporated in the evaporator 1 flows into the absorber 2 and is absorbed by the solution sprayed in the absorber 2. A heat transfer tube 11 is disposed in the absorber 2, cooling water flows inside the tube, and an absorbing solution is sprayed outside the tube. The absorption action in the absorber 2 proceeds by the cooling water taking away the latent heat of condensation that occurs when the absorbing liquid absorbs the refrigerant vapor. The absorbing solution whose concentration has been reduced by absorbing the refrigerant is pressurized by the solution circulation pump 7 and first flows into the low-temperature heat exchanger 8. The low-temperature heat exchanger 8 exchanges heat with the high-concentration solution returned from the regenerator 5, and the temperature of the low-concentration solution rises.
[0013]
In this embodiment, a low-concentration solution whose temperature has risen out of the low-temperature heat exchanger 8 is branched, and one is sent to the low-temperature regenerator 4 and the other is sent to the high-temperature regenerator 5 side. Indicates the utility cycle. The solution sent to the high temperature regenerator 5 first passes through the high temperature heat exchanger 9. Here, heat is exchanged with the solution returning from the high temperature regenerator 5, and the temperature further rises. By heating the low-concentration solution whose temperature has risen with the high-temperature regenerator 5, the refrigerant is evaporated from the solution. In the high-temperature regenerator 5, heating is performed by using, as a heat source, combustion heat using fuel (for example, fuel gas), steam generated by a boiler, waste heat generated in other facilities, and the like. The refrigerant vapor generated in the high temperature regenerator 5 is sent to the low temperature regenerator 4.
[0014]
In the high-temperature regenerator 5, the solution whose concentration has been increased by evaporating the refrigerant returns to the high-temperature heat exchanger 9, where heat is exchanged with the low-concentration solution flowing to the high-temperature regenerator 5 to decrease the temperature. The high-concentration solution exiting the high-temperature heat exchanger 9 joins with the solution returning from the low-temperature regenerator 4 and is sent to the low-temperature heat exchanger 8. A heat transfer tube 13 is disposed in the low temperature regenerator 4, the refrigerant vapor generated in the high temperature regenerator 5 flows inside the tube, and the absorbing liquid is scattered outside the tube. The low concentration solution sent to the low temperature regenerator 4 is heated by the heat transfer tube 13 to evaporate the refrigerant vapor. The solution whose concentration has been increased by evaporating the refrigerant exits the low temperature regenerator 4 and joins the returned solution from the high temperature regenerator 5. A solution pump may be used to send the combined high-concentration solution to the low-temperature heat exchanger 8, but this is omitted in this embodiment.
[0015]
The low concentration solution and the high concentration solution whose temperature has been reduced by the heat exchanger are sent to the absorber 2 and reused as the absorbing solution. The refrigerant vapor generated in the high temperature regenerator 5 heats the solution in the heat transfer tube 13 of the low temperature regenerator 4 and condenses in the tube, and the condensed refrigerant is sent to the condenser 3. Refrigerant vapor generated by evaporation outside the low-temperature regenerator 4 is also sent to the condenser 3. A heat transfer tube 12 is disposed in the condenser 3, cooling water flows inside the tube, the refrigerant vapor is cooled outside the tube, and the refrigerant vapor is condensed. The liquid refrigerant generated in the condenser 3 is sent to the evaporator 1 through the pipe 35, whereby one cycle is completed, and thereafter this cycle is repeated.
[0016]
In order to extract the non-condensable gas staying in the absorber 2, an extraction device 14 is provided in the absorber 2 (in this embodiment, it is one example, but it may be two, for example). ). The bleeder 14 branches a part of the discharge-side solution pressurized by the solution circulation pump 7 and uses the solution sent through the pipe (or channel) 19 as a driving fluid.
[0017]
FIG. 2 is a cross-sectional view of the bleeder, and FIG. 3 is a perspective view of main parts of the bleeder. A discharge nozzle 33 is attached to the pipe 19, and a swirl vane 33a is formed in the discharge nozzle 33 to give a swirl flow to the discharged solution, promoting mixing of the solution and non-condensable gas, and improving extraction efficiency. Has the effect of causing The suction tube 20 is disposed to face the discharge port 33 b of the discharge nozzle 33, and the discharge nozzle 33 and the suction tube 20 are disposed in parallel with the heat transfer tube 11. By disposing the discharge nozzle 33 and the suction pipe 20 in parallel with the heat transfer pipe 11, the interference portion on the arrangement of the extraction device 14 and the heat transfer pipe 11 is reduced, and compared with the case where the heat transfer pipe is arranged vertically. More heat transfer tubes 11 can be arranged, and the heat exchange efficiency can be increased. Or, in order to obtain an equivalent amount of heat exchange, the absorber 2 can be saved in space. By injecting the solution in a direction parallel to the heat transfer tube 11, non-condensable gas is sucked together with the refrigerant vapor by the suction tube 20, and an extraction operation is performed. The inner diameter of the suction tube 20 is made larger than the inner diameter of the discharge port 33b. That is, by reducing the inner diameter of the discharge nozzle nozzle 33, it is possible to increase the jet flow velocity, and thereby the suction action is more effectively performed.
[0018]
The solution sent by the pipe 19 is jetted by the discharge nozzle 33, is turned into a swirling flow, and the non-condensable gas is extracted together with the refrigerant vapor around the discharge nozzle 33 (indicated by the solid line arrow) and sucked into the pipe 20. . To a solution injected from the discharge nozzle 33 is free Captures noncondensable gas, and injected solution and the uncondensed gas is necessary to flow commingled well, this mixing line in the pipe 20 Is called. Therefore, it is preferable that the straight portion (L) of the pipe 20 has a length approximately four times or more the inner diameter (R) from the inlet (ie, L> 4R). When L <4R, the mixing action of the solution and the non-condensable gas is reduced, the non-condensable gas is not taken into the pipe 20, and the extraction efficiency is lowered.
[0019]
Returning to FIG. 1, the solution that has taken in the non-condensable gas is sent to the suction side pipe 20 of the solution circulation pump 7. The non-condensable gas extracted by the absorber 2 is pressurized by the solution circulation pump 7 together with the solution exiting the absorber 2 and is carried in the solution circulation cycle. The noncondensable gas carried by the solution is released at the same time as the solution evaporates the refrigerant vapor in the low temperature regenerator 4 and the high temperature regenerator 5. The non-condensable gas released from the low-temperature regenerator 4 flows into the condenser 3 together with the refrigerant vapor, and the non-condensable gas released from the high-temperature regenerator 5 flows into the condenser 3 through the low-temperature regenerator 4 together with the refrigerant vapor. The non-condensable gas collected in the condenser 3 is extracted by an extraction device 15 connected to the condenser 3.
[0020]
As a specific means of the bleeder 15 , a solution driven ejector 15 is used in this embodiment. A part of the discharge solution having a circulating pump 7 is guided to a solution driven ejector 15 through a pipe 21 by driving the solution driving the ejector 15, bleeds noncondensable gas together with the refrigerant vapor. The extracted solution absorbs the refrigerant vapor in the pipe 22. The pipe 22 is connected to the gas-liquid separator 16, and the solution mixed with the non-condensable gas is guided to the gas-liquid separator 16. Here, the non-condensable gas and the solution are separated, and the solution flows through the pipe 23 connecting the staying portion and the suction side of the solution circulation pump 7 and is returned to the suction side pipe of the solution circulation pump 7. The non-condensable gas separated by the gas-liquid separator 16 flows through the pipe 25 and is guided to the air storage tank 17.
[0021]
In order to efficiently store the non-condensable gas in the limited volume of the air storage tank 17, it is preferable that the non-condensable gas can be pressurized. When returning the solution from the gas-liquid separator 16 to the suction side of the solution circulation pump 7 in order to keep the gas-liquid separator 16 at a higher pressure than the absorber 2 and pressurize the non-condensable gas in the gas storage tank 17, the return pipe 23 Is raised to a predetermined height (the height varies depending on the degree of pressurization of the non-condensable gas), and a pipe 24 is connected to the uppermost part of the raised pipe so as to communicate with the gas phase part of the absorber 2. The top of 23 is equalized with the absorber 2. Then, the return pipe 23 is lowered and connected to the suction side of the solution circulation pump 7. By adopting such a configuration, the liquid pressure corresponding to the difference in height between the uppermost portion of the return pipe 23 and the gas-liquid separator 16 is applied to the gas-liquid separator 16.
[0022]
When the gas-liquid separator 16 is pressurized, an equal pressure is applied to the non-condensable gas, and the non-condensable gas in the gas storage tank 17 is compressed. When the non-condensable gas is stored in the air storage tank 17 to some extent, the water-driven ejector 18 is operated to discharge the non-condensable gas to the atmosphere. However, normally, the valve 27 provided in the pipe 26 between the air storage tank 17 and the water drive ejector 18 is closed, and the water drive ejector 18 is not operated. As the valve 27, for example, an electromagnetic valve controlled to be opened only when the water-driven ejector 18 is operated may be used, and two valves may be used in series for safety. At the same time, a check valve is used together with the valve 27 to prevent air from flowing into the chamber. For driving the water-driven ejector 18, it is possible to use cold water flowing through the evaporator 1 as a driving source in the immediate vicinity. A valve 29 is provided in the pipe 28 for guiding the cold water to the water-driven ejector 18 and is normally closed. In order to operate the water drive ejector 18 only when non-condensable gas is stored in the air storage tank 17 and the gas needs to be discharged, it is preferable to use an electromagnetic valve as the valve 29.
[0023]
According to the present embodiment, by disposing the discharge nozzle and the suction pipe of the absorption device in parallel with the heat transfer tube, the interference part on the arrangement of the extraction device and the heat transfer tube is reduced, and the heat transfer tube is arranged vertically. More heat transfer tubes can be arranged as compared with the case, and the heat exchange efficiency can be increased. Alternatively, when obtaining an equivalent amount of heat exchange, the absorber can be saved in space and the absorption refrigerator can be downsized.
Moreover, the extraction effect | action which extracts non-condensable gas is performed within an absorber, pressure loss is eliminated by making an extraction piping unnecessary, and it can aim at the improvement of extraction efficiency by this.
[0024]
FIG. 4 is a system diagram of a second embodiment according to the absorption refrigerator of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, description thereof will be omitted, and only different parts will be described.
[0025]
In the present embodiment, the pipe 31 that sends the solution from the solution circulation pump 7 to the discharge nozzle 33 of the bleeder 14 is passed through the refrigerant retention portion of the evaporator 1 before being connected to the discharge nozzle 33. The solution can be cooled by passing the solution used for extraction through the refrigerant retention part of the evaporator 1 having a low temperature. When sucking non-condensable gas by jetting the solution, the space to be sucked, that is, the inside of the bleeder 14 does not drop below the saturation pressure of the solution. Therefore, when the saturation pressure of the solution is high, efficient bleed cannot be expected. . Since the saturation pressure of the solution can be lowered by lowering the temperature, cooling of the extraction solution leads to improvement of extraction efficiency.
[0026]
In addition to the above, the extraction solution cooling means includes a method using cooling water and a method using cold water. Even when the refrigerant is used as a cold heat source as in this embodiment, the solution pipe 31 is passed through the inside of the evaporator 1 to directly contact the pipe with the refrigerant and cooled, and the solution pipe 31 is connected to the evaporator 1. Although there is a method of indirect cooling by contacting the wall, any method can be used for effective cooling.
[0027]
Further, when a low-pressure evaporator / absorber and a high-pressure evaporator / absorber are configured with two stages of evaporators and absorbers, the extraction effect can be enhanced by cooling the solution for extraction. When the evaporator and the absorber are configured in two stages, the non-condensable gas is easily collected by the low-pressure side absorber, so that the extraction can be effectively performed by providing the extraction device in the low-pressure side absorber. However, since the solution is also absorbed by the absorber on the high-pressure side and becomes a solution having a reduced concentration, the saturation pressure with respect to the solution temperature is increased. For this reason, the extraction capability when this solution is used for extraction is low. Therefore, efficient extraction can be performed by cooling the solution and lowering the saturation pressure and using it for extraction.
[0028]
Next, the solution return pipe 32 from the gas-liquid separator 16 is connected to the absorber 2. In this case, the connection place between the pipe 32 and the absorber 2 is a gas phase portion, and the pipe 32 is connected to a predetermined height position in order to apply a liquid pressure to the gas-liquid separator 16. Thereby, piping can be simplified.
According to the present embodiment, the extraction effect can be enhanced by cooling the solution for extraction, and the piping can be simplified.
[0029]
FIG. 5 is a system diagram of a third embodiment according to the absorption refrigerator of the present invention. Parts identical to those in FIGS. 1 and 2 are given the same reference numerals and explanation thereof is omitted, and only different parts will be explained. The difference from the embodiment of FIGS. 1 and 2 is that the extraction of the condenser 3 is performed by the extraction device 33. The structure of the bleeder 33 is the same as that of the bleeder shown in FIG.
[0030]
According to the present embodiment, space extraction of the condenser can be achieved by using the extraction device shown in FIG.
[0031]
【The invention's effect】
According to the absorption refrigerator of the present invention as described above, to reduce the heat transfer tube comprising a discharge nozzle and a suction pipe thus failure of the bleed device and space saving, we are possible to miniaturize, to bleed the noncondensable gas that extract the gas-piping to eliminate the need to eliminate the pressure loss aims to improve the extraction efficiency, cut in miniaturization.
[Brief description of the drawings]
FIG. 1 is a system diagram of a first embodiment according to the absorption refrigerator of the present invention.
FIG. 2 is an enlarged view of the bleed device in the embodiment of FIG. 1;
FIG. 3 is a perspective view of essential parts of the bleeder in the embodiment of FIG. 1;
FIG. 4 is a system diagram of a second embodiment according to the absorption refrigerator of the present invention.
FIG. 5 is a system diagram of a third embodiment according to the absorption refrigerator of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Evaporator 2 Absorber 3 Condenser 4 Low temperature regenerator 5 High temperature regenerator 7 Solution circulation pump 10-13 Heat transfer pipe 14 Extraction device 15 Solution drive ejector 16 Gas-liquid separator 17 Gas storage tank 18 Water drive ejector 33 Nozzle

Claims (6)

An absorption refrigeration cycle is configured by connecting an evaporator, an absorber having heat transfer tubes extending in multiple stages in the horizontal direction, a condenser, a regenerator, and a solution circulation pump to separate the solution and the non-condensable gas. In an absorption refrigerator equipped with a liquid separator,
A bleed device having a discharge nozzle having a solution discharge port and a suction pipe having a suction port facing the discharge port on the same axis is provided in the absorber.
The discharge nozzle and the suction pipe are arranged so as to extend in parallel between the heat transfer pipes, and the inlet side of the discharge nozzle is connected to a flow path for guiding a part of the discharge solution of the solution circulation pump, The outlet side of the suction pipe is connected to a flow path leading to the suction side of the solution circulation pump, and the non-condensable gas together with the refrigerant vapor around the discharge nozzle in the absorber by the solution sprayed from the discharge port of the discharge nozzle Is extracted into the suction pipe.   The absorption refrigerator according to claim 1, wherein a blade for providing a swirl flow to the solution is provided in the discharge nozzle.   The absorption refrigerator according to claim 2, wherein the straight portion of the suction pipe has a length that is at least four times the inner diameter of the suction pipe. The absorption refrigerator according to claim 1, wherein a part of the solution discharged from the solution circulation pump is cooled in an evaporator and then guided to a discharge nozzle of the extraction device.   The absorption refrigerator according to claim 1, wherein the absorber comprises a low-pressure absorber and a high-pressure absorber, and an extraction device is provided in the low-pressure absorber. A solution-driven ejector driven by a solution , an air storage tank for storing non-condensable gas, a valve connected to the air storage tank, and a water-driven ejector driven by water , the solution-driven ejector being one of the discharge solutions of the solution circulation pump The suction portion of the solution driven ejector is connected to the condenser, and the solution outflow portion of the solution driven ejector is connected to the gas-liquid separator, and above the gas-liquid separator After arranging a gas storage tank, connecting the gas phase part of the gas-liquid separator and the gas storage tank, and raising the pipe connected to the liquid phase part of the gas-liquid separator to a predetermined height, the solution and connected to the suction side or the absorber of the circulating pump, connected via a valve to the suction portion of the water driven ejector driven by the gas storage tank and the water, the absorption refrigerating the outflow of water in the water driven ejector The opening on the outside, guide the noncondensable gas bled by the absorber in the condenser by the solution circulation pump leads the noncondensable gas in the gas storage tank from the condenser through the solution driving ejector and the gas-liquid separator The absorption refrigerator according to claim 1, wherein non-condensable gas is discharged to the outside by the water-driven ejector.

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