Title of Invention

ABSORPTION REFRIGERATOR.

Abstract

TITLE: ABSORPTION REFRIGERATOR. AN ABSORPTION REFRIGERATOR; COMPRISES A HIGH TEMEPRATURE REGENERATOR, A LOW TEMPERATURE REGENERATOR, A CONDENSER, AN EVAPORATOR, AN ABSORBER, A LOW TEMPERATURE HEAT EXCHANGER AND A HIGH TEMPERATURE HEAT EXCHANGER, WHEREIN, A FIRST EXHAUST GAS HEAT RECOVERY EQUIPMENT WHERE AN EXHAUST GAS FROM THE COMBUSTION EQUIPMENT AND THE DILUTED ABSORPTION SOLUTION HAVING PASSED THROUGH THE HEAT EXCHANGER EXCHANGE THE HEAT, A SECOND EXHAUST GAS HEAT RECOVERY EQUIPMENT WHERE THE EXHAUST GAS HAVING PASSED THROUGH SAID FIRST EXHAUST GAS HEAT RECOVERY EQUIPMENT AND THE DILUTED ABSORPTION SOLUTION, HAVING PASSED THROUGH THE HEAT EXCHANGER BEFORE ENTERING THE HEAT EXCHANGER EXCHANGE THE HEAT, A BYPASS ABSORPTION SOLUTION PIPE OR BYPASS EXHAUST PIPE BYPASSING SAID SECOND EXHAUST GAS HEAT RECOVERY EQUIPMENT AND MERGING WITH THE DILUTED ABSORPTION SOLUTION PIPE OR AN EXHAUST PIPE HAVING PASSED THROUGH THE SECOND EXHAUST GAS HEAT ERECOVERY EQUIPMENT, A VALVE INTERPOSED IN THE DILUTED ABSORPTION SOLUTION PIPE OR THE EXHAUST PIPE PASSING THROUGH THE SECOND EXHAUST GAS HEAT RECOVERY EQUIPMENT OF THE DILUTED ABSORPTION SOLUTION PIPE OR THE EXHAUST PIPE WHERE SAID BYPASS ABSORPTION SOLUTION PIPE OR BYPASS EXHAUST PIPE IS PROVIDED, A TEMPERATURE SENSOR FOR DETECTING THE EXHAUST GAS FLOWING IN THE DOWNSTREAM PORTION OF THE FIRST EXHAUST GAS HEAT RECOVERY EQUIPMENT AND A CONTROL MEANS FOR CONTROLLING THE OPENING/CLOSING OF SAID VALVE BASED ON THE EXHAUST HGAS TEMPERATURE ARE DISPOSED.

Full Text

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention concerns an absorption refrigerator. 2. Description of the Prior Art An absorption refrigerator devised to cut the fuel consumption by sending consecutively an exhaust gas discharged from a gas burner for heating and boiling a diluted absorption solution of a high temperature regenerator to a first exhaust gas heat recovery equipment disposed between a high temperature heat exchanger and a high temperature regenerator of an absorption solution pipe, and then to a second exhaust gas heat recovery equipment disposed between a low temperature heat exchanger and the high temperature heat exchanger, increasing the temperature of the diluted absorption solution to be transported from an absorber to the high temperature regenerator and reducing the heat quantity required by the gas burner is well-known. In short, in the absorption refrigerator of the aforementioned composition, the diluted absorption solution of about 40°C (during the rated operation, hereinafter) discharged from the absorber is heated respectively by the low temperature heat exchanger, the second exhaust gas heat recovery equipment, the high temperature heat exchanger, and the first exhaust gas heat recovery equipment, heated around 140°C, before flowing in the high temperature regenerator, allowing to economize fuel to be consumed by the gas burner. It should be noted that, in this absorption refrigerator, in case where both the temperature of the exhaust gas discharged from the gas burner and the temperature of the diluted absorption solution supplied from the absorber are low, the quantity of diluted absorption solution flowing in the absorption solution pipe (bypass absorption solution pipe) is increased by increasing the opening of the flow control valve, the discharge gas temperature is prevented from dropping remarkably by reducing the heat recovery from the exhaust gas in the second exhaust gas heat recovery equipment, in a way to prevent the vapor contained in the exhaust gas from condensing and dewing. However, in the aforementioned absorption refrigerator of the prior art, as the flow control valve is provided in the absorption solution pipe (bypass absorption solution pipe) bypassing the second exhaust gas heat recovery equipment, not small quantity of diluted absorption solution flows in the second exhaust gas heat recovery equipment through the absorption solution pipe even if the flow control valve is opened fully. SUMMARY OF THE INVENTION Consequently, in case where both the temperature of the exhaust gas and the temperature of the diluted absorption solutions are low, for instance, during the operation start, the temperature of the exhaust gas drops sometimes excessively even if the flow control valve is opened fully, the water vapor contained in the exhaust gas condenses and dews, eroding sometimes the heat exchanger and the exhaust pipe; therefore, it is necessary to provide an absorption refrigerator of a composition exempt from the occurrence of such inconveniences. In order to solve the aforementioned problems of the prior art, the present invention provides an absorption refrigerator of a first composition, comprising a high temperature regenerator for evaporating and separating a refrigerant by heating and boiling it by a combustion equipment and obtaining a refrigerant vapor and an intermediate absorption solution from a diluted absorption solution, a low temperature regenerator for heating the intermediate absorption solution generated and supplied by said high temperature regenerator with the refrigerant vapor generated by the high temperature regenerator and for evaporating and separating the refrigerant furthermore, to obtain a refrigerant vapor and a dense absorption solution from the intermediate absorption solution, a condenser for being supplied with a refrigerant liquid condensed by heating the intermediate absorption solution in said low temperature regenerator and, at the same time, to obtain a refrigerant liquid by cooling the refrigerant vapor generated and supplied by said low temperature regenerator, an evaporator for evaporating the refrigerant by cooling a fluid flowing in a heat conductive pipe on which the refrigerant liquid supplied from said condenser is spread, an absorber for absorbing the refrigerant vapor generated and supplied by said evaporator with the dense absorption solution supplied by separating the refrigerant vapor from the low temperature regenerator for making a diluted absorption solution and supplying it to the high temperature regenerator, a low temperature heat exchanger where the diluted absorption solution and the dense absorption solution flowing in and out said absorber exchange the heat, and a high temperature heat exchanger where the intermediate absorption solution and the diluted absorption solution flowing in and out said absorber exchange the heat; wherein, a first exhaust gas heat recovery equipment where an exhaust gas discharged from the combustion equipment and the diluted absorption solution having passed through the high temperature heat exchanger exchange the heat, a second exhaust gas heat recovery equipment where the exhaust gas having passed through said first exhaust gas heat recovery equipment and the diluted absorption solution, having passed through the low temperature heat exchanger, before entering the high temperature heat exchanger exchange the heat, a bypass absorption solution pipe or bypass exhaust pipe bypassing said second exhaust gas heat recovery equipment and merging with the diluted absorption solution pipe or an exhaust pipe having passed through the second exhaust gas heat recovery equipment, a valve interposed in the diluted absorption solution pipe or the exhaust pipe passing through the second exhaust gas heat recovery equipment of the diluted absorption solution pipe or the exhaust pipe where said bypass absorption solution pipe or bypass exhaust pipe is provided, a temperature sensor for detecting the exhaust gas flowing in the downstream portion of the first exhaust gas heat recovery equipment, and a control means for controlling the opening/closing of said valve based on the exhaust gas temperature are disposed. In an absorption refrigerator of a second composition, said absorption refrigerator of the first composition comprises a diluted absorption solution branch pipe where a part of dilute absorption solution discharged from the absorber bypasses the low temperature heat exchanger, exchanges heat with heat radiation refrigerant discharged from the low temperature regenerator and introduces into the second exhaust gas heat recovery equipment. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS These and others and advantages of the present invention will become clear from following description with reference to the accompanying drawings, wherein : Fig. 1 is an illustrative drawing showing a first embodiment of the present invention ; Fig. 2 is an illustrative drawing showing a second embodiment of the present invention; Fig. 3 is an illustrative drawing showing a third embodiment of the present invention; Fig. 4 is an illustrative drawing showing a fourth embodiment of the present invention; and Fig. 5 is an illustrative drawing showing a prior art. [Description of Symbols] 1 High temperature regenerator 2 Gas burner 3 Low temperature regenerator 4 Condenser 5 Hot drum 6 Evaporator 7 Absorber 8 Hot drum 9 Low temperature heat exchanger 10 High temperature heat exchanger 11, 11A, 12, 13 Absorption solution pipe 11B Absorption solution pipe (bypass absorption solution pipe) 11C Absorption solution pipe (diluted absorption solution branch pipe) 14 Absorption solution pump 15 to 19 Refrigerant pipe 19 Refrigerant pump 20 Cold water pipe 21 Cooling water pipe 22, 22A Exhaust pipe 22B Exhaust pipe (bypass exhaust pipe) 23 First exhaust gas heat recovery equipment 24 Second exhaust gas heat recovery equipment 25 Flow control valve 25A Selector valve 26 Temperature sensor 27 Controller 28 Refrigerant heat recovery equipment DETAILED DESCRIPTION OF THE PRIOR ART As shown in Fig. 5, an absorption refrigerator devised to cut the fuel consumption by sending consecutively an exhaust gas discharged from a gas burner 2 for heating and boiling a diluted absorption solution of a high temperature regenerator 1 to a first exhaust gas heat recovery equipment 23 disposed between a high temperature heat exchanger 10 and a high temperature regenerator 1 of an absorption solution pipe 11, and then to a second exhaust gas heat recovery equipment 24 disposed between a low temperature heat exchanger 9 and the high temperature heat exchanger 10, increasing the temperature of the diluted absorption solution to be transported from an absorber 7 to the high temperature regenerator 1 and reducing the heat quantity required by the gas burner 2 is well-known. In short, in the absorption refrigerator of the aforementioned composition, the diluted absorption solution of about 40°C (during the rated operation, hereinafter) discharged from the absorber 7 is heated respectively by the low temperature heat exchanger 9, the second exhaust gas heat recovery equipment 24, the high temperature heat exchanger 10, and the first exhaust gas heat recovery equipment 23, heated around 140°C, before flowing in the high temperature regenerator 1, allowing to economize fuel to be consumed by the gas burner 2. It should be noted that, in the composition, in case where both the temperature of the exhaust gas discharged from the gas burner 2 and the temperature of the diluted absorption solution supplied from the absorber 7 are low, the quantity of diluted absorption solution flowing in the absorption solution pipe (bypass absorption solution pipe) 11B is increased by increasing the opening of the flow control valve 25, the discharge gas temperature is prevented from dropping remarkably by reducing the heat recovery from the exhaust gas in the second exhaust gas heat recovery equipment 24, in a way to prevent the vapor contained in the exhaust gas from condensing and dewing. However, in the aforementioned absorption refrigerator of the prior art, as the flow control valve 25 is provided in the absorption solution pipe (bypass absorption solution pipe) 11B bypassing the second exhaust gas heat recovery equipment 24, not small quantity of diluted absorption solution flows in the second exhaust gas heat recovery equipment 24 through the absorption solution pipe 1A even if the flow control valve 25 is opened fully. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT While the presently preferred embodiment of the present invention has been shown and described, it will be understood that the present invention is not limited thereto, and that various changes and modification may be made by those skilled in the art without departing from the scope of the invention as set forth in the appended claims. Now, embodiments of the present invention shall be described taking an example of an absorption refrigerator using water as refrigerant and aqueous solution of lithium bromide (LiBr) as absorption solution. [First Embodiment] The first embodiment shall be described based on Fig. 1. In the drawing, 1 is a high temperature regenerator composed to heat the absorption solution by the heating power of a gas burner 2 using for instance city gas as fuel for evaporating and separating the refrigerant, 3 a low temperature regenerator, 4 a condenser, 5 a hot drum containing the low temperature regenerator 3 and the condenser 4, 6 an evaporator, 7 an absorber, 8 a cold drum containing the evaporator 6 and the absorber 7, 9 a low temperature heat exchanger, 10 a high temperature heat exchanger, 11 to 13 absorption solution pipes, 14 an absorption solution pump, 15 to 18 refrigerant pipes, 19 a refrigerant pump, 20 a cold water pipe, 21 a cooling water pipe, 22 an exhaust pipe for passing exhaust gas from the gas burner 2, 23 a first exhaust gas heat recovery equipment, 24 a second exhaust gas heat recovery equipment, 25 a flow control valve, 26 a temperature sensor for detecting the temperature of the exhaust gas flowing in the downstream portion of the exhaust pipe 22, and 27 a controller for controlling the opening of the flow control valve 25 so that the temperature sensor 26 continues to detect a predetermined temperature, say 100 °C. In the absorption refrigerator of the aforementioned composition, when the diluted absorption solution is heated and boiled by the high temperature regenerator 1 with combustion of city gas by the gas burner 2, a refrigerant vapor evaporated and separated from the diluted absorption solution, and an intermediate absorption solution condensed in absorption solution by separating the refrigerant vapor can be obtained. A hot refrigerant vapor produced in the high temperature regenerator 1 enters the low temperature regenerator 3 passing through the refrigerant pipe 15, heats the intermediate absorption solution produced by the high temperature regenerator 1 and delivered to the low temperature regenerator 3 passing through the high temperature heat exchanger 10 by the absorption solution pipe 11, radiates heat and condenses itself before entering the condenser 4. On the other hand, the refrigerant heated by the low temperature regenerator 3 and evaporated and separated from the intermediate absorption solution enters the condenser 4, condenses and liquefies through heat exchange with water flowing in the cooling water pipe 21, joins the refrigerant condensed and supplied from the refrigerant pipe 16, passes through the refrigerant pipe 17 before entering the evaporator 6. The refrigerant liquid delivered to the evaporator 6 and accumulated in a refrigerant liquid accumulator is spread by a refrigerant pump 19 over a heat conductive pipe 20A connected to a cold water pipe 20 and evaporates through heat exchange with water supplied through the cold water pipe 20, and refrigerates the water flowing in the interior of the heat conductive pipe 20A. The refrigerant evaporated in the evaporator 6 is delivered to the absorber 7, heated by the low temperature regenerator 3 for evaporating and separating the refrigerant, and absorbed by an absorption solution further increased in the absorption solution concentration, namely dense absorption solution, supplied through the low temperature heat exchanger 9 by the absorption solution pipe 13 and spread from above. Then, absorption solution reduced in the concentration by absorbing the refrigerant in the absorber 7, in short, the diluted absorption solution is heated respectively in the low temperature heat exchanger 9, the second exhaust gas heat recovery equipment 24 (a part thereof flows in the absorption solution pipe (bypass absorption solution pipe) 11B and bypasses), the high temperature heat exchanger 10, and the first exhaust gas heat recovery equipment 23, by operating the absorption solution pump 14, and delivered to the high temperature regenerator 1 from the absorption solution pipe 11. When the absorption refrigerator is operated as mentioned above, cold water chilled by the heat of evaporation of the refrigerant in the heat conductive pipe 20A disposed in the interior of the evaporator 6 can be supplied by circulation to a not shown air-conditioning load through the cold water pipe 20, allowing to perform a refrigeration operation such as cooling. In the absorption refrigerator of the aforementioned composition, similarly to the absorption refrigerator of the prior art shown in Fig. 5, as the diluted absorption solution of about 40 °C of the absorber 7 to be transported to the high temperature regenerator 1 by the absorption solution pump 14 is heated respectively in the low temperature heat exchanger 9, the second exhaust gas heat recovery equipment 24 (a part of diluted absorption solution bypasses), the high temperature heat exchanger 10, and the first exhaust gas heat recovery equipment 23, the temperature of the diluted absorption solution rises around 140 °C before being delivered to the high temperature regenerator 1, allowing to cut the fuel consumption of the gas burner 2 more than an absorption refrigerator without the first exhaust gas heat recovery equipment 23 and the second exhaust gas heat recovery equipment 24. In short, thanks to the controller 27, as the recovery of heat held in the exhaust gas is accelerated by supplying the second exhaust gas heat recovery equipment 24 through the absorption solution pipe 11A with much of the diluted absorption solution delivered from the absorber 7 to the high temperature regenerator 1 by increasing the opening of the flow control valve 25 while the temperature sensor 26 is detecting a temperature over the predetermined 100 °C. Furthermore, in the absorption refrigerator of the present invention, as it is possible to control the quantity of heat recovered from the exhaust gas up to the maximum zero by closing completely the flow control valve 25 to the maximum limit, until the total quantity of diluted absorption solution bypasses the second exhaust gas heat recovery equipment 24 and flows in the absorption solution pipe (bypass absorption solution pipe) 11B, when the temperature sensor 26 detects a temperature under 100 °C, the temperature of the exhaust gas discharged from the gas burner 2 and flowing in the exhaust pipe 22 is maintained to 100 °C over the dew-point temperature (the dew-point temperature of the combustion exhaust gas when city gas, namely natural gas is used as fuel is 60 to 70 °C), whereby, drain water will not be produced by condensation of water vapor contained in the exhaust gas, even during the starting or partial load operation when both temperatures of the exhaust gas and the diluted absorption solution are low, nor corrosion problems due to drain water be provoked. [Second embodiment] The second embodiment shall be described based on Fig. 2. In the absorption refrigerator of the second embodiment, a refrigerant heat recovery equipment 28 is provided, in addition to the piping composition of the absorption refrigerator of the first embodiment shown in Fig. 1. And, the refrigerant heat recovery equipment 28 is supplied with the refrigerant directed from the low temperature regenerator 3 to the condenser, namely the refrigerant obtained by heating the intermediate absorption solution in the low temperature regenerator 3 for evaporating, separating and condensing the refrigerant and a part of diluted absorption solution being transported to the high temperature regenerator 1 from the absorber 7 by the absorption solution pump 14, namely the diluted absorption solution flowing in the absorption solution pipe (bypass absorption solution pipe) 11C provided by bypassing the low temperature heat exchanger 9 for exchanging heat, so as to recover the after heat held in the refrigerant liquid by the diluted absorption solution being transported to the high temperature regenerator 1. The other piping composition is similar to said absorption refrigerator of the first embodiment. In the absorption refrigerator of the second embodiment, a part of diluted absorption solution returned to the high temperature regenerator 1 from the absorber 7 by the operation of the absorption solution pump 14, passes through the low temperature heat exchanger 9 interposed in the absorption solution pipe 11, the remainder passes through the refrigerant heat recovery equipment 28 interposed in the absorption solution pipe (bypass absorption solution pipe) 11C, and heated by respective heat exchanger. Besides, the quantity of diluted absorption solution to be heated by the exhaust gas exiting the gas burner 2 passing through the second exhaust gas heat recovery equipment 24 is controlled by the flow control valve 25 interposed in the absorption solution pipe 11A, whole the quantity of diluted absorption solution returning from the absorber 7 to the high temperature regenerator 1 flows through the high temperature heat exchanger 10 and the first exhaust gas heat recovery equipment 23 and is heated in them respectively. In short, a part of diluted absorption solution of about 40 °C discharged from the absorber 7 into the absorption solution pipe 11 is heated to about 85 °C by exchanging the heat in the low temperature heat exchanger 9 with dense absorption solution of about 90 °C discharged from the low temperature regenerator 3 into the absorption solution pipe 13 and flowing in the absorber 7, while the remainder is heated to 70 °C by exchanging the heat in the refrigerant heat recovery equipment 28 with refrigerant of about 95 °C of the refrigerant pipe 16 condensed in the low temperature regenerator 3 and flowing in the condenser 4, they flow together, become for instance a diluted absorption solution of around 80 °C and flow through the absorption solution pipe 11 toward the high temperature regenerator 1. Also, the flow rate of diluted absorption solution flowing in the second exhaust gas heat recovery equipment 24 is controlled by the controller 27 similarly to the absorption refrigerator of the first embodiment shown in Fig. 1. In short, the controller 27 accelerates recovery of heat held in the exhaust gas by increasing the opening of the flow control valve 25 when the temperature sensor 26 detects a temperature over the predetermined 100 °C, and delivers more diluted absorption solution to the second exhaust gas heat recovery equipment 24. On the other hand, as it is possible to control the heat quantity recovered from the exhaust gas up to the maximum zero by closing completely the flow control valve 25 to the maximum, until the total quantity of diluted absorption solution bypasses the second exhaust gas heat recovery equipment 24 and flows in the absorption solution pipe (bypass absorption solution pipe) 11B, when the temperature sensor 26 detects a temperature under 100 °C, the temperature of the exhaust gas discharged from the gas burner 2 and flows in the exhaust pipe 22 is maintained to 100 °C over the dew-point temperature whereby, drain water will not be produced by condensation of water vapor contained in the exhaust gas, even during the starting or partial load operation when both temperatures of the exhaust gas and the diluted absorption solution are low, nor corrosion problems due to drain water be provoked. Then, the diluted absorption solution heated by passing through the second exhaust gas heat recovery equipment 24, and the diluted absorption solution that did not passed through the second exhaust gas heat recovery equipment 24 and, consequently, that was not heated flow together, pass through the high temperature heat exchanger 10 and the first exhaust gas heat recovery equipment 23, exchange the heat with the intermediate absorption solution flowing from the high temperature regenerator 1 to the low temperature regenerator 3 through the absorption solution pipe 12 and the exhaust gas of about 200 °C discharged from the gas burner 2, become a diluted absorption solution of the order of 140 °C, and flow in the high temperature regenerator 1, allowing to economize fuel to be consumed by the gas burner 2. Besides, as the refrigerant liquid condensed in the low temperature regenerator 3 and flowing in the condenser 4 through the absorption solution pipe 16 heats the diluted absorption solution of about 40 °C by exchanging the heat in the refrigerant heat recovery equipment 28 as mentioned above, and the refrigerant liquid itself is refrigerated to about 45 °C (in place of about 95 °C in the prior art) and flows in, the heat quantity to be radiated to the cooling water flowing in the interior of the cooling water pipe 21 is reduced. As a result, the required heat input quantity for the high temperature regenerator 1 can be cut, and the heat efficiency will further be improved than the absorption refrigerator of the first embodiment shown in Fig. 1. [Third embodiment] The third embodiment shall be described based on Fig. 3. In the absorption refrigerator of the third embodiment, an exhaust pipe (bypass exhaust pipe) 22B bypassing the second exhaust gas heat recovery equipment 24 is provided in place of the absorption solution pipe (bypass absorption solution pipe) 11B provided in the absorption refrigerator of the first embodiment shown in Fig 1 and, furthermore, a selector valve 25A is provided at the branching portion of the exhaust pipe 22A passing through second exhaust gas heat recovery equipment 24 and the exhaust pipe (bypass exhaust pipe) 22B in place of the flow control valve 25. It should be noted that the temperature sensor 26 is installed in the exhaust pipe 22 more upstream than the branching portion of the exhaust pipe 22A and the exhaust pipe (bypass exhaust pipe) 22B. The other piping composition is same as the absorption refrigerator of the first embodiment. Moreover, in the absorption refrigerator of the third embodiment, the controller 27 changes over the selector valve 25A, so as to recover heat of the exhaust gas by flowing the whole quantity of exhaust gas discharged from the gas burner 2 into the second exhaust gas heat recovery equipment 24 when the temperature sensor 26 detects a temperature over a predetermined temperature, say 150 °C, and by flowing the whole quantity of exhaust gas bypassing the second exhaust gas heat recovery equipment 24 when the temperature sensor 26 detects a temperature under the predetermined 150 °C, in a way to prevent the temperature of the exhaust gas from dropping remarkably. Consequently, in the absorption refrigerator of the third embodiment also, fuel to be consumed by the gas burner 2 can be cut, and the heat efficiency will be improved. Besides, the temperature of the exhaust gas discharged from the second exhaust gas heat recovery equipment 24 would never be under the required temperature, for instance 100 °C. Whereby, drain water will not be produced by condensation of water vapor contained in the exhaust gas, nor corrosion problems due to drain water be provoked. [Fourth embodiment] The fourth embodiment shall be described based on Fig. 4. In the absorption refrigerator of the fourth embodiment also, a exhaust pipe (bypass exhaust pipe) 22B bypassing the second exhaust gas heat recovery equipment 24 is provided in place of the absorption solution pipe (bypass absorption solution pipe) 11B provided in the absorption refrigerator of the second embodiment shown in Fig. 2 and, furthermore, a selector valve 25A is provided at the branching portion of the exhaust pipe 22A passing through second exhaust gas heat recovery equipment 24 and the exhaust pipe (bypass exhaust pipe) 22B in place of the flow control valve 25. I It should be noted that the temperature sensor 26 is installed in the exhaust pipe 22 more upstream than the branching portion of the exhaust pipe 22A and the exhaust pipe (bypass exhaust pipe) 22B similarly to the absorption refrigerator of the third embodiment, so the other piping composition is same as said absorption refrigerator of the second embodiment. And, in the absorption refrigerator of the fourth embodiment also, similarly to the absorption refrigerator of the third embodiment, the controller 27 changes over the selector valve 25A, so as to recover heat held in the exhaust gas by flowing the whole quantity of exhaust gas discharged from the gas burner 2 into the second exhaust gas heat recovery equipment 24 when the temperature sensor 26 detects a temperature over a predetermined temperature, say 150 °C, and by flowing the whole quantity of exhaust gas bypassing the second exhaust gas heat recovery equipment 24 when the temperature sensor 26 detects a temperature under the predetermined 150 °C, in a way to prevent the temperature of exhaust gas from dropping remarkably. Consequently, in the absorption refrigerator of the fourth embodiment also, fuel to be consumed by the gas burner 2 can be cut, and the heat efficiency will be improved. Besides, the temperature of the exhaust gas discharged from the second exhaust gas heat recovery equipment 24 would never be under the required temperature, for instance 100 °C. Whereby, drain water will not be produced by condensation of water vapor contained in the exhaust gas, nor corrosion problems due to drain water be provoked. It should be appreciated that the invention is not limited to the aforementioned embodiment, but may be modified in various ways without departing from the scope of the invention as set forth in the appended claims. For example, an inexpensive on-off valve may be installed in place of the flow control valve 25, and the on-off thereof may be controlled simply by the controller 27 so that the exhaust temperature detected by the temperature sensor 26 is not under a predetermined temperature. Besides, in place of the flow rate control valve 25, it may also be constituted to install a selector valve or a flow rate control valve capable of distribution rate control on the end portion of the absorption solution pipe 11 A, namely on the branching portion with the absorption solution pipe (bypass absorption solution pipe) 11B, or on the confluence portion thereof. Moreover, in the absorption refrigerator of the third and fourth embodiments shown in Fig. 3 and Fig. 4, it may also be constituted to install a second temperature sensor for detecting the exhaust gas temperature in the upstream direction of the confluence portion of the exhaust pipe 22A and the exhaust pipe (bypassing exhaust pipe) 22B. Further, it may also be constituted to exchange over the selector valve 25A by the controller 27 for flowing the whole quantity of exhaust gas discharged from the gas burner 2 bypassing the second exhaust gas heat recovery equipment 24 when the second temperature sensor detects a temperature under the predetermined 100 °C, and flowing the whole quantity of exhaust gas discharged from the gas burner 2 into the second exhaust gas heat recovery equipment 24 when the temperature sensor 26 detects a temperature, say by 5 °C, over the temperature detected when the second temperature sensor detects a temperature under the predetermined 100 °C. Besides, an absorption solution pipe (bypass absorption solution pipe) 13A and an absorption solution pump 29 can also be installed as shown by broken lines in Fig. 2 and Fig. 4, on the absorption solution pipe 13 conducting the dense absorption solution heated and concentrated in the low temperature regenerator 3 to the absorber 7 through the low temperature heat exchanger 9. Also, the absorption refrigerator may be composed exclusively for the refrigeration operation such as the aforementioned room cooling, or devised to perform heating operation such as room heating by connecting the piping so that the cold drum 8 can be supplied directly with refrigerant vapor heated and generated in the high temperature regenerator 1 and absorption solution obtained by evaporating and separating the refrigerant vapor, heating the diluted absorption solution by the gas burner 2 without delivering cooling water to the cooling water pipe 21, and supplying a load by circulation with a water heated for instance to the order of 55 °C in the heat conductive pipe 20A of the evaporator 6 through the cold water pipe 20 (preferably, called hot water pipe in case of circulating hot water). In addition, in the absorption refrigerator of the third and fourth embodiment shown in Fig. 3 and Fig. 4 provided with the refrigerant heat recovery equipment 28, it is also possible to install the refrigerant pipe 16 in a way to flow in the evaporator 6 not in the condenser 4, as the refrigerant supplied from the low temperature regenerator 3 radiates heat into the diluted absorption solution in the refrigerant heat recovery equipment 28, reducing the temperature sufficiently. Besides, the fluid refrigerated or like in the evaporator 6 and supplied to an air-conditioning load may be the water or others to be supplied without phase change as in the aforementioned embodiment, or chlorofluorocarbon or the like to be supplied with phase change, so that a heat transport using latent heat would be enabled. As mentioned hereinabove, according to the present invention, it is possible to recover effectively heat held in the exhaust gas. Moreover, drain water will not be produced by condensation of water vapor contained in the exhaust, nor corrosion problems due to drain water be provoked, because the abnormal fall of exhaust gas temperature can be prevented by controlling heat recovery completely to zero during the starting or partial load operation lowering the exhaust gas temperature. WE CLAIM : 1. An absorption refrigerator; comprising a high temperature regenerator for evaporating and separating a refrigerant by heating and boiling it by a combustion equipment and obtaining a refrigerant vapor and an intermediate absorption solution from a diluted absorption solution, a low temperature regenerator for heating the intermediate absorption solution generated and supplied by said high temperature regenerator with the refrigerant vapor generated by the high temperature regenerator and for evaporating and separating the refrigerant furthermore, to obtain a refrigerant vapor and a dense absorption solution from the intermediate absorption solution, a condenser for being supplied with a refrigerant liquid condensed by heating the intermediate absorption solution in said low temperature regenerator and, at the same time, to obtain a refrigerant liquid by cooling the refrigerant vapor generated and supplied by said low temperature regenerator, an evaporator for evaporating the refrigerant by cooling a fluid flowing in a heat conductive pipe on which the refrigerant liquid supplied from said condenser is spread, an absorber for absorbing the refrigerant vapor generated and supplied by said evaporator with the dense absorption solution supplied by separating the refrigerant vapor from the low temperature regenerator for making a diluted absorption solution and supplying it to the high temperature regenerator, a low temperature heat exchanger where the diluted absorption solution and the dense absorption solution flowing in and out said absorber exchange the heat, and a high temperature heat exchanger where the intermediate absorption solution and the diluted absorption solution flowing in and out said absorber exchange the heat ; wherein, a first exhaust gas heat recovery equipment where an exhaust gas discharged from the combustion equipment and the diluted absorption solution having passed through the high temperature heat exchanger exchange the heat, a second exhaust gas heat recovery equipment where the exhaust gas having passed through said first exhaust gas heat recovery equipment and the diluted absorption solution, having passed through the low temperature heat exchanger, before entering the high temperature heat exchanger exchange the heat, a bypass absorption solution pipe or bypass exhaust pipe bypassing said second exhaust gas heat recovery equipment and merging with the diluted absorption solution pipe or an exhaust pipe having passed through the second exhaust gas heat recovery equipment, a valve interposed in the diluted absorption solution pipe or the exhaust pipe passing through the second exhaust gas heat recovery equipment of the diluted absorption solution pipe or the exhaust pipe where said bypass absorption solution pipe or bypass exhaust pipe is provided, a temperature sensor for detecting the exhaust gas flowing in the downstream portion of the first exhaust gas heat recovery equipment, and a control means for controlling the opening/closing of said valve based on the exhaust gas temperature are disposed. 2. The absorption refrigerator as claimed in claim 1, comprising a diluted absorption solution branch pipe where a part of dilute absorption solution discharged from the absorber bypasses the low temperature heat exchanger, exchanges heat with heat radiation refrigerant discharged from the low temperature regenerator and introduces into the second exhaust gas heat recovery equipment. 3. An absorption refrigerator substantially as herein described, particularly with reference to the accompanying drawings. An absorption refrigerator ; comprises a high temperature regenerator (1), a low temperature regenerator (3), a condenser (4), an evaporator (6), an absorber (7), a low temperature heat exchanger (9), and a high temperature heat exchanger (10), wherein, a first exhaust gas heat recovery equipment (23) where an exhaust gas from the combustion equipment (2) and the diluted absorption solution having passed through the heat exchanger (10) exchange the heat, a second exhaust gas heat recovery equipment (24) where the exhaust gas having passed through said first exhaust gas heat recovery equipment (23) and the diluted absorption solution, having passed through the heat exchanger (9), before entering the heat exchanger (10) exchange the heat, a bypass absorption solution pipe or bypass exhaust pipe (11B) bypassing said second exhaust gas heat recovery equipment and merging with the diluted absorption solution pipe or an exhaust pipe having passed through the second exhaust gas heat recovery equipment, a valve (25) interposed in the diluted absorption solution pipe or the exhaust pipe passing through the second exhaust gas heat recovery equipment of the diluted absorption solution pipe or the exhaust pipe where said bypass absorption solution pipe or bypass exhaust pipe is provided, a temperature sensor (26) for detecting the exhaust gas flowing in the downstream portion of the first exhaust gas heat recovery equipment, and a control means (27) for controlling the opening/closing of said valve based on the exhaust gas temperature are disposed.

Documents:

00097-kol-2003-abstract.pdf

00097-kol-2003-claims.pdf

00097-kol-2003-correspondence.pdf

00097-kol-2003-description (complete).pdf

00097-kol-2003-drawings.pdf

00097-kol-2003-form 1.pdf

00097-kol-2003-form 18.pdf

00097-kol-2003-form 2.pdf

00097-kol-2003-form 3.pdf

00097-kol-2003-form 5.pdf

00097-kol-2003-gpa.pdf

00097-kol-2003-letter patent.pdf

00097-kol-2003-priority document others.pdf

00097-kol-2003-reply f.e.r.pdf