MXPA01002275A - Absorption refrigeration machine - Google Patents

Abstract

The invention relates to an absorption refrigeration machine using the Platen-Munters system and comprising a generator (7) for evaporating a refrigerant in a solvent;a solvent separator (2) in which the solvent is separated from the refrigerant;a condenser (3) for liquefying the refrigerant;an evaporator (4) in which the refrigerant is evaporated using a dry gas while being cooled;possibly a first gas heat exchanger (6);and an absorber (5) in which the evaporated refrigerant is added to the depleted mixture of refrigerant and solvent which is then again evaporated in the generator (7). The output of the evaporator (4) or the output of the first gas heat exchanger (6) which is possibly positioned downstream of the evaporator (4) and the output of the generator (7) discharge into a bypass (8) connected to the absorber (5). The mixture of evaporated refrigerant and dry gas which arrives from the evaporator (4) via the first gas heat exchanger (6) is transferred to the generator output and from there into the bypass (8), where the gas mixture is brought into contact with the hot, partly degassed solution coming from the generator (7) and withdraws further refrigerant from same.

Description

ABSORPTION REFRIGERATION MACHINE FIELD OF THE INVENTION The invention relates to an absorption refrigeration machine according to the Platen-Munters system with a generator for evaporating a refrigerant in a solvent, a solvent separator wherein the separation of the solvent from the refrigerant a condenser is made to liquefy the refrigerant, an evaporator in which the refrigerant is evaporated using a dry gas as long as it is cooled, optionally with a first gas heat exchanger, and an absorber in which the evaporated refrigerant is added to the degraded mixture of the refrigerant and solvent that then evaporates again in the generator. BACKGROUND OF THE INVENTION In order to evaporate a known absorption refrigeration machine according to the Platen-Munters system it is necessary to have a heat source with a temperature widely above 100 ° C. At temperatures of 100 ° C and below, on the other hand, the degree of efficiency tends to 0. Existing heat sources at low temperatures, such as hot water from industrial waste heat systems, for example distant heat, solar heating or the like, they are not suitable for the hitherto present embodiments of these absorption machines since the high temperatures required in general can not be achieved. The object of the invention is therefore a first-time absorption cooling machine, with which a high degree of efficiency is also achievable with a relatively low temperature of preferably 75 ° C. According to the invention this is achieved because the outlet of the evaporator or the outlet of the first gas heat exchanger optionally disposed after the evaporator and the generator outlet, lead to a bypass leading to the absorber where the mixture is conducted. which comes from the evaporator through the first heat exchange of gas from the cooling agent and the dry gas at the generator outlet and through the bypass, where the gas mixture is put in partially gassed contact with the solution coming from the generator and here more coolant is removed, the mixture coming from the evaporator through the first heat exchanger is therefore not transferred directly to the absorber but instead to the generator outlet and from there through the bypass and Refrigerant is withdrawn from the solution coming from the generated one, and it is also possible to omit the first gas heat exchanger, so that In this case, the mixture is guided from the outlet of the evaporator to the inlet of the bypass. In both cases it is possible to reach a low solution concentration inlet in the area of the absorber inlet, which is a precondition for a low cooling temperature without the generator having to be strongly heated. Therefore, low temperature sources can be used for the absorption refrigeration machine according to the invention. As a result of the low temperature of the generator, the quantity of water evaporated simultaneously is reduced, thus avoiding any loss in evaporator efficiency. In another embodiment of the invention it can be provided that a second heat exchanger is provided whose primary side is disposed between the outlet of the evaporator and, if necessary, the outlet of the first gas heat exchanger and the bypass inlet and its side. The secondary gas is arranged between the outlet of the bypass and the inlet of the absorber, so that the gas mixture coming from the bypass cools. The cooling of the gas mixture allows the improvement of the enrichment of the degraded liquid coming from the generator. The derivation allows a low operating temperature, but also causes loss of energy. According to another embodiment of the invention, it can be provided that a control valve is provided between the outlet of the evaporator and the inlet of the absorber or between the inlet and outlet of the bypass, with which the quantity of gas can be dosed the amount of gas diverted through the bypass, where the non-diverted part flows directly to the absorber. With this, it is possible to regulate the derivation step effect in the necessary straight temperature decrease of the heat supply source. According to a variant of the invention, the control valve can be a straight-through valve that bypasses the bypass so that with the valve open the bypass does not work and with the valve closed the bypass enters a complete operation. According to another variant of the invention, the regulating valve can be a three-way valve, which divides the gaseous mixture coming from the evaporator between the flow to the branch and the flow to the absorber. In this way the derivation can be adjusted exactly in its derivation. To increase the contact surface between the gaseous mixture flowing through the bypass and that of the liquid flowing through it, the inner wall of the bypass tube can be coated with an ammonia resistant fiber material, where the Ammonia resistant fiber is preferably formed by a fiberglass fleece, where the requirements of a large area and high strength are met. Another feature of the invention may be that inside the bypass tube, a coil spring is disposed that rests on its inner wall where the ammonia-resistant fiber material can be tensioned between the inner wall and the coil spring. In this way, the cross section of the bypass flow is prevented from decreasing for the gas flowing through the branch. A particular efficiency is achieved according to another embodiment of the invention by causing the refrigerant to be formed of ammonia and the solvent to be water. It can also be provided that the bypass be heatable, thus making the temperature of the bypass adjustable to a value at which the gas mixture flowing inward removes a very high proportion of ammonia from the degraded solution. The invention also relates to a bubble pump for an absorption cooling machine for at least one vertical pump tube which is heatable by a gaseous liquid heat carrier medium and in which a cooling solution can be moved upwards by forming of bubble. The circulation of the liquid in absorption refrigeration machines is often maintained by the so-called "Mammut" pump or "bubble pumps". For example in the classical Platen-Munters system in which water is used as a solvent and ammonia as cooling or refining agent .. Since for the operation of this absorption-cooling machine the energy can be obtained from a This heat source is excellently suited for the transformation of solar energy into cold. Until now, bubble pumps are not generally usable or with sufficient success for heating by means of heat carriers with variable temperature as they occur in obtaining solar energy. Jal buxbuj.a pump consists of two mutually communicating containers that are filled with a solution of water ammonia. and not of these containers properly the active part of the pump, is arranged in a small upward tube that is heated, so that the ammonia is released inside. The gas bubbles produced push the solution upwards in the narrow tube. In some bubble pumps, a small gas collector can be found in the tube pointing upwards in which the tube penetrates from above. The gas is collected there before it pushes up the liquid in the tube located above. In the two above mentioned types of bubble pumps there is a critical internal temperature range in which the gas bubbles form so slowly that they are too small to fill the entire cross section of the pump tube and therefore, they will migrate upwards without dragging any liquid. Thus, the concentration of ammonia will decrease in the pump tube. According to the thermodynamic data of the ammonia solution in water at the temperature at which the ammonia can be released and then increased. In the case of a slow increase in the temperature of the pump, the minimum temperature required will increase simultaneously and there may be situations in which the bubble pump completely fails to perform its service, because the pump tube will only contain water and properly no ammonia . The aforementioned gas collecting vessel is provided to reduce this danger. Particularly in the application of - solar energy a progress of temperature over time occasionally still occurs in which the bubble pumps with gas collecting vessels still fail to function as a result of the above mentioned effect. In the case of an excessively slow start or a cooling process that is also excessively slow, the cooling solution may lose too much gas, and the bubble pump may be permanenout of operation. This problem can also occur in gas-cooled ammonia absorption refrigeration machines, for example when the gas burner is plugged. The pump can then only be reactivated when the entire cooler has been turned down as a result of which the Arachis-rich solution reaches the pump tube again. This process is not feasible in large refrigerators which is the reason why large refrigeration units are usually not equipped with bubble pumps without or with electric transport pumps. In permanent operation, an optimum degree of cooling effect requires accurate dosing of the performance of the pump regardless of the heating temperature. SUMMARY OF THE INVENTION It is therefore the object of the present invention to provide a bubble pump of the aforementioned type with which a failure of the bubble pump in the critical temperature range is avoided and where permanent operation and a continuous operation are allowed. absorption refrigeration machine.

This is achieved according to the invention in such a way that the lower end of the at least one pump tube is connected to a heatable elongate container that drives the pump, pump operating vessels provided with an inlet opening and one of known and from which the cooling solution flows into the pump tube and can flow through a substantially horizontal direction, with the inlet opening and the outlet opening arranged in such a way that a gas bubble produced in the driving vessel of the pump, stop at the same with the liquid level of the coolant solution in cold state being below the active pump pump pump range. Before the cooling solution enters the pumping tube, it is moslocated in the pump drive vessel that is heated to a temperature that is always slighbelow the actual heating temperature of the pump. pumping. Once the heating temperature rises, a gas bubble forms in the aforementioned drive or shot container of the pump, gas bubble which due to the shape of the container can not flow out of it and therefore displaces the solution, so that the liquid level rises through the currenhot pump tube, so that the pumping process is put into action. If on the other hand the temperature reaches the critical range, for example when only very little ammonia is released, the pump drive level is already so cold that the ammonia enters the solution, the gas bubble disappears and the solution is removed. xetira of the bubble pump. This is an important difference to the gas collector vessels direcheated as known in this aspect and in which the pump tube is submerged, because no condensation of the gas bubble can occur while the temperature in the active range of the bubble pump is still above the minimum gas slug temperature. Yet another difference is that the pump drive vessel is preferably in the form of a lying tube or any other form of enlarging surface through which the coolant solution flows over the container as a thin-bed layer underneath. the gas bubble and swirls in the process, allowing then the complete resorption of the bubble "on cooling, because in the case of a liquid without swirling as in the conventional gas collection vessel, a thin layer of the much lighter liquid ammonia will specifically form on the surface which prevents Any other solution processing In the bubble pump according to the invention the refrigerant solution is thus automatically withdrawn from it when the heating temperature decreases to a critical range.On the other hand the water ammonia solution can only be located in the active area of the bubble area at temperatures above the minimum gas production temperature corresponding to the respective system pressure It can be provided in another embodiment of the invention that the pump driving vessel is formed by a horizontally arranged hollow cylinder with cover surfaces , with opening of entrance and exit provided in the zo inferior surface of the opposite deck surfaces. As a result, the gas bubble that occurs automatically in case of heating is prevented from escaping through the outlet opening. According to another embodiment of the invention, it can be provided that the pump driving vessel is enclosed by a heating jacket through which a gaseous or liquid heat carrier medium is conveyed. This makes it possible to set the temperature of the pump drive container independently of the temperature in the bubble pump, with a temperature slightly lower than the temperature prevailing in the bubble pump and which has been consistently chosen, so that the range of Critical temperature is reached inside the pump drive vessel already before this, and the shrinking gas bubble pulls the cooling solution back from the pump tube. It can therefore be provided in accordance with another embodiment of the invention that the small temperature difference required between the bubble pump and the pump drive vessel is achieved in such a way that the heat-carrying heating medium flows first through the pump. of the bubble pump and then through the pump drive vessel. According to another alternative embodiment of the invention, the pump tube can be surrounded by a first concentric heating jacket so that it flows through a gaseous or liquid heat carrier medium and with a second concentric heating jacket for a liquid heat carrier medium. because it can be arranged between the pump tube and the first concentric heating jacket, the liquid level of the liquid liquid heat-carrying medium being within the second concentric heating jacket. In this way, it is possible to adjust all the thermal resistance of the container forming the bubble pump according to the invention to the heat flow that is needed. In addition, the supply of heat to the pump tube can be regulated independently of the temperature of the heat transfer medium flowing through the first concentric heating jacket. In absorption cooling machines with a generator, an absorber and a condenser it is possible, in another embodiment of the invention to arrange a temperature sensor on the connecting tube between the generator and the absorber or the connecting tube between the generator and the condenser and provide a controller unit with which the performance of the pump can be controlled depending on the temperature measured by the sensor. The measurements in the refrigeration machines by absorption and precise calculations prove that the degree of cooling effect is only optimal when the performance of the pump or pumping of the bubble pump is constant. The performance of the pump fluctuates strongly, however, in the case of a variable heating temperature in the case of solar energy.The necessary control of pump performance can be carried out in such a way that the thermal energy supplied to the pump bubbles can, supplied independently of the temperature which is controllable both by a variable contact surface between the heat carrier medium coming from the solar unit and the pump tube of the bubble pump as well as, by the change of the transmission coefficient of heat in this place. According to another embodiment of the invention there is a further possibility to control the heat transfer coefficient in the bubble pump by changing the flow velocity of the heat carrier medium. Since the coefficient of heat transmission between a medium and a solid body increases with the flow velocity of this medium and the heat carrier medium needs to be circulated in any case, such control of the heat transfer coefficient may be coupled in a preferably with a control of the flow rate of the heat carrier liquid. Preferably the progression of the temperature between the generator and the absorber or between the generator and the condenser of the cooling system can be used as an amount of the pump output because a larger output or pump performance will push the temperature range elevated towards the absorber or the condenser. Another feature of the invention may be that the second concentric heating jacket is connected to a gas thermometer by means of which gas, upon expansion upon heating, the liquid level within the second concentric heating jacket may be adjusted. The gas that expands upon heating displaces the liquid from the variable heating jacket around the bubble pump tube which is representative of the variable thermal resistance. Preferably, the position of the gas thermometer represents the possibility to adjust the performance of the pump. If the gas thermometer moves more towards the absorber or more towards the condenser where the contact surface of the tube is cooler, the heating jacket around the bubble pump will automatically increase and pump more strongly. If on the other hand, the heating temperature of the pump rises, it will pump more quickly and the temperature will rise in the gas thermometer thus displacing the liquid in the pump jacket and winding the pump. BRIEF DESCRIPTION OF THE DRAWINGS. The invention is now explained in more detail with reference to the accompanying drawings. Wherein: Figure 1 is a schematic representation of an embodiment of the absorption refrigeration machine according to the invention. Figure 2 is a schematic representation of an embodiment of the absorption refrigeration machine according to the invention. - Figure 3 is a diagram on the degree of efficiency reached experimentally by the absorption refrigeration machine according to the invention. with the invention at different operating temperatures depending on the adjustment of the bypass regulating valve. Figure 4 is a section through a derivation in representation in an oblique view. Figure 5 is an embodiment of a bubble pump according to the invention. DESCRIPTION OF THE INVENTION The absorption refrigeration machine described below works extensively like the classical Platen-Munters system, which is used in the absorption refrigerator of Electrolux and Servel (registered trademarks) and is widely documented. The absorption refrigeration cooling machine includes a generator 7 for the evaporation of a refrigerant dissolved in a solution agent, with a bubble pump 1, a separator of the solution agent 2, in which the solvent separation of the refrigerant takes place , a condenser 3 for the liquefaction of the refrigerant, an evaporator 4 in which the refrigerant by means of dry gas and under cooling evaporates, a first gas heat exchanger 6 and an absorber 5 where the degraded mixture of refrigerant and Solution agent is added evaporated refrigerant, mixture qμe evaporates again in the generator 7. For a better understanding, the invention is clarified by means of an example of embodiment in which the solvent is formed by water and the refrigerant by ammonia. Other refrigerants and solution agents can also be used in the context of the invention. According to the solution it is provided that the outlet of the first gas heat exchanger 6 arranged after the evaporator 4 and the outlet of the generator 7, lead to a bypass 8 leading to the absorber 5 where the mixture coming from the first evaporator 4 to through the first gas heat exchanger 6, formed from the evaporated refrigerant and the feco gas, it is conducted to the generator outlet 7 and from there by the bypass 8, where the gaseous mixture is brought into contact with the solution coming from the generator 7 hot partially degassed and from this the coolant is removed again. In this way, the absorption cooling machine according to the invention can be operated with a relatively low generator heating temperature, which can be below 100 ° C.

However, the first gas heat exchanger 6 can also be omitted, in which case the outlet of the evaporator 4 opens directly on the bypass 8. In the bubble pump 6 which in the illustrated embodiment is formed of one or several parallel and vertical tubes, it is conducted to a concentrated ammonia solution in case the heat coming from the heat exchanger 11 does not suffice more heat, which is formed in the pump -of bubble 1, bubbles of ammonia gas , whose volume represents only a scanty percentage compared to the total amount of gas that is then released in the generator 7. The ascending ammonia gas bubbles lead the solution through the thin tubes upwards to a separator of water 2. The ammonia separates: water from the water flows through a rising tube 9 more upwards towards the condensate 3 where it is liquefied by cooling. The liquid ammonia flows through a U-19 tube to the evaporator 4, where as a thin film it wet the wall of a tube through which a dry gas, for example hydrogen gas, flows. Here the ammonia vapor produced is continuously removed, which leads to the cooling of the evaporator 4, whereby the cooling process proper to the machine according to the invention is achieved or maintained. The mixture of ammonia gas and hydrogen at the lower end of the evaporator 4 is specifically heavier than the enriched gas mixture flowing in the evaporator 4, thereby keeping the hydrogen circuit in use. In a system hitherto usual, the gaseous mixture was flowed directly to the absorber 5. But in the absorption cooling machine according to the invention, it branches off after a first gas heat exchanger 6 in the direction of the generator 7, where, in a bypass 8, a hot degassed medium solution flows in the same direction or against the current, and comes from the generator 7 removing more ammonia due to the temperature and vapor pressure ratios that determine the concentration. It should be noted that the gas that becomes increasingly heavy should not rise too high, because this would reduce the flow velocity. In this way it is possible to achieve a low concentration of the solution in the upper part of the absorber 5 which is a precondition for a low cooling temperature without the need to strongly heat the generator 7. As a result of that lower generator temperature, the amount The water evaporated simultaneously is also limited, making any subsequent rectification of the steam-water mixture of the ammonia unnecessary by ascending the pipe 9 and avoiding any subsequent loss of efficiency by water in the evaporator. The mixture of the ammonia gas and hydrogen coming through the evaporator and optionally and through the first gas heat exchanger 6, is further guided as illustrated in Figure 1 on the primary side of a second gas heat exchanger 10 to the output of the generator 7 and then in parallel or countercurrent stream through the derivation ß and subsequently to cool through the secondary side of the second gas heat exchanger 10 and then to the absorber 5 where its excess ammonia is released to the weak solution coming from the branch 8. In this case it is necessary that the absorber 5 be provided with larger dimensions than in a conventional system. Because the gaseous mixture flowing from the branch 8 to the absorber 5 has a higher ammonia vapor pressure than in the conventional Planten-Munters system flowing from below to the absorber 5, the solution flowing out of the absorber has an higher speed which subsequently allows the gas to be withdrawn at a lower temperature in the generator 7. The solution moves from the absorber 5 through the liquid heat exchanger 11 to the bubble pump 1. It rises there and after the separator water 2, the solution that only slightly weakens the bubble formation in bubble bomb 1 flows to generator 7 where the quitai process itself takes place by heating; the gas. An expansion vessel-pressurized gas 12 is disposed between the end of the condenser 3 and the hydrogen circulation is provided to prevent additional ammonia from reaching the hydrogen circulation in the case of an excessive generator temperature. In the pressure gas expansion vessel 12, the light hydrogen forms a layer on the heavier ammonia as a result of which only the boundary or border layer between the two gases is displaced in the case of temperature fluctuations in the circulation of ammonia. The said pressurized gas expansion vessel 12 then prevents the hydrogen from reaching the condenser 3 through the U-tube 19 in the case of low generator temperatures and which makes condensation difficult there. In the embodiment according to Figure 2 the quantity of gas mixture redirected to the branch 8 can be metered by means of a control valve 13 when the non-redirected rest flows directly to the absorber 5 as it is known in the Platen system. Munters. The control valve may preferably be a direct passage valve representative of a short circuit or jump to the tap. Although the branch 8 allows a lower operating temperature, it uses energy in itself. By regulation, the efficiency of the bypass must be adjusted as low as possible to the collapse of the supply heat temperature. In Figure 3, a measured degree of efficiency (on the axis of the ordinates) of the absorption cooling machine according to the invention is represented. In derivations strongly regulated differently and different heating temperatures (abscissa axis) for the generator 7. Curve 14 shows the degree of efficiency with the disconnected branch, the curve 14 the degree of efficiency with the establishment of the valve of regulation 15 to the half of the operation of the branch and curve 16 the degree of efficiency with the maximum operation of the branch. In Figure 4 a possible shaping is shown to increase the contact surface between the gas mixture and the solution in the branch 8. A fiber fleece of the glass or a material similarly resistant to ammonia with large surface 17 is preferably pressed by a coil spring 18 against the wall of the branch pipe 8. Figure 5 shows in schematic form a bubble grove according to the invention. The cooling solution coming from a generator 32 via an absorber 35 of an absorption cooling machine flows to the low inlet of a bubble pump 36 which is provided with a vertical pump tube 26 which can be heated by a heat carrier medium. liquid or gaseous and in which the cooling solution such as ammonia - water, can move upwards by the formation of bubbles. A derivation according to the modalities shown in Figures 1 to 4 can also be provided optimally. The use of the bubble pump according to the invention offers the advantages even in conventional absorption cooling machines. It is provided according to the invention, that the lower end of the pump tube 26 is connected to an oblong-shaped heatable pump driving vessel 25 which is provided with an inlet opening and an outlet opening 21 and 22, and which can be traversed substantially in the horizontal direction by the cooling solution flowing in the pump tube 26. The inlet and outlet openings 21 and 22 are arranged in such a way that a gas bubble 24 produced in the drive container or pump shot 25 is retained therein with the liquid level of coolant solution '23 being below the active pump margin of pump tube 26 in the cold state.

The pump drive vessel is formed by a horizontally disposed hollow cylinder 25 with cover surfaces with the inlet opening and the outlet opening 21, 22 provided in the lower region of opposed cover surfaces with respect to each other. Any suitable shaping of the pump drive vessel is possible. The gas bubble 24 shown in Figure 5 presses the level of the liquid upwards into the pump tube 26. The solution is further heated there by a heat carrier medium in a first concentric heating jacket 27 through a second sleeve concentric heating 28 partially filled, as a result of which the gas bubbles are produced which transport the liquid to a gas separator 31 from which the partially no-gas solution returns to the generator 32, from which the gas continues to flow upwards in the direction towards a condenser (not shown). The heat carrier medium 30 first flows through the outer heating jacket 27 of the bubble pump and from there through a heating jacket 30 of the pump driving means 25 back to the heat source. A small temperature difference between the bubble pump and the bubble drive container 25 is achieved in such a way that the hot heat carrying medium flows firstly through the bubble pump and then through the heat transfer vessel. bubble. The flow rate of the heat carrier liquid can be adjustable in order to vary the heat flow to the bubble pump. In addition, a temperature sensor may be provided on the connecting tube between the generator 32 between the generator 32 and the absorber 35 or on the connecting tube between the generator 32 and the condenser (not shown), as a result of which the output or Pump performance can be controlled depending on the temperature measured by the sensor. One possible embodiment comprises a gas thermometer 34. This heats up in the conduit between the generator 32 and the absorber 35 and thus the expanding gas displaces through a flexible line 33 the liquid carrying heat from the heating jacket internal 28 to a pressure expansion vessel 29 as a result of which the heated surface of the pump tube 26 is reduced. In this way it is possible to establish the heat flow through the pump tube 26 as required.

Claims (18)

1. NOVELTY OF THE INVENTION Having described the invention as above, the content of the following is claimed as property: CLAIMS. 1. Absorption or cooling machine according to the Platen-Munters system with a generator for the evaporation of a cooling agent dissolved in a solvent, a separator of the solvent agent where the solvent separation of the refrigerant people is carried out, a condenser for the liquefaction of the cooling agent, an evaporator wherein the cooling agent by means of a dry gas and with cooling evaporates, optionally a first gas heat exchanger and an absorber in which the degraded or depleted mixture of cooling agent and The solvent receives a cooling agent, which evaporates again in the generator, characterized in that the outlet of the evaporator or the outlet of the first gas exchanger, if necessary after the evaporator and the generator outlet, flow into a bypass leading to the absorber, where the mixture composed of cooling agent and dry gas comes that of the evaporator through the first int Gas heat exchanger, is led to the generator outlet and to the bypass, where the "gas mixture with the solution coming from the hot generator and partially without gas, is put in contact, and more coolant is removed. Machine and absorption refrigeration according to claim 1, characterized in that a second gas heat exchanger is provided whose primary side "is placed between the outlet of the evaporator or, if necessary, the outlet of the first gas heat exchanger and of entrance of the bypass step and whose secondary side is placed between the outlet of the bypass 7 / the entrance of the absorber, so that the gaseous mixture coming from the bypass is cooled. 3. Cooling machine by absorption in accordance with the claim 1 or 2, characterized in that between the outlet of the evaporator and the inlet of the absorber or between the inlet and outlet of the bypass a regulating valve is arranged with which the amount of the gas diverted by the bypass is donated by the non-diverted part flows directly to the absorber 4. The absorption refrigeration machine according to claim 3, characterized in that the regulating valve is a bypass valve that short-circuits or bypasses the bypass - 5. Absorption refrigeration machine according to claim 3, characterized in that the regulating valve is a three-way valve which divides the mixture gaseous that comes from the evaporator between a flow to the bypass and a flow to the absorber. Absorption refrigeration machine according to one of the preceding claims, characterized in that the internal wall of the bypass tube is coated with an ammonia-resistant fiber material. 7. An absorption cooling machine according to claim 6, characterized in that the ammonia-resistant fiber material is formed by a fiberglass fleece. 8. An absorption cooling machine according to claim 6 or 7, characterized in that a helical spring is placed inside the bypass tube that rests on the inner wall, where the ammonia resistant fiber material is tensioned between the wall internal and helical spring. 9. An absorption cooling machine according to one of the preceding claims, characterized in that the cooling agent is ammonia and the solvent is r. Absorption cooling machine according to one of the preceding claims, characterized in that the branch is heatable. 11. Bubble pump for an absorption refrigeration machine __ with less a vertical pump tube which is heatable by a gaseous or liquid heat carrier medium according to and in which a solution of cooling agent is movable upwards by the bubble formation, characterized in that the lower end of the at least one pump tube is connected to an elongate heatable vessel that operates the pump, which pump drive vessel has an inlet opening and an outlet opening and is movable by the stream of the solution of a, cooling people flowing in the pump tube in an essentially horizontal direction, where the inlet opening and the outlet opening are arranged in such a way that a gas bubble is produced in the actuating container of pump, stops at this and where the liquid level of the coolant solution in the cold state is below the active pump pump pump zone. Bubble pump according to claim 11, characterized in that the pump drive container is formed by a horizontally arranged hollow cylinder with cover surfaces, where the inlet opening and the outlet opening are arranged in the lower region of the cover surfaces opposite each other. 13. Bubble pump according to claim 11 or 12, characterized in that the drive container. The pump is surrounded by a heating jacket through which a liquid or gaseous heat carrier medium is conductive. 14. Bubble pump according to claim 11, 12 or 13, characterized in that the pump tube is surrounded by a first concentric heating jacket to be traversed by a liquid or gaseous heat carrier medium, and between the pump tube and the first concentric heating jacket is provided with a second concentric heating jacket for a heat carrier medium whose liquid level is adjustable within the second concentric heating jacket. 15. Bubble pump according to claim 14, characterized in that the flow velocity of the heat carrier liquid is adjustable. Bubble pump according to one of the preceding claims 13 - 15, characterized in that the small difference in temperature required between the bubble pump and the pump drive vessel is achieved by the heat carrier medium traversing its current first the bubble pump and then the pump drive container. Bubble pump according to one of the preceding claims 11 - 16, for an absorption cooling machine, with a generator, an absorber and a condenser, characterized in that a temperature sensor is arranged in the connecting tube between the generator and the absorber or in the connecting pipe between the generator and the condenser, and a regulating unit is provided with which the performance of the pump is adjustable depending on the temperature measured by the sensor. 18. Bubble pump according to claim 1, characterized in that the second concentric heating jacket is connected to a gas thermometer by means of which, in the heating of the expanding gas, the level of liquid inside the second jacket is adjustable. of concentric heating.