Title of Invention

"AN IMPROVED ABSORPTION REFRIGERATOR "

Abstract

The purpose of the present invention is to improve the thermal efficiency of an absorption refrigerator. The absorption refrigerator is provided with the refrigerant heat recovery equipment 11 for performing heat exchange between the refrigerant which radiated heat and is condensed by heating the intermediate absorption solution in the low temperature regenerator 3 and is introduced into the condenser 4 through the refrigerant pipe 20, and a part of the dilute absorption solution discharged from the absorber 7 and sent to the high temperature regenerator 1 bypassing the low temperature heat exchanger 9, and the rotation speed of the absorption solution pump 18 is controlled by the controller 33 so that the temperature of the dense absorption solution detected by the temperature sensor 32 is higher than a predetermined temperature, for example 40°C.

Full Text

SPECIFICATION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerator. 2. Detailed Description of the Prior Art As shown in Fig. 2, such an absorption refrigerator is known, as is devised to reduce the amount of heat necessary by a gas burner 2 and reduce fuel consumption by sequentially sending the exhaust gas exhausted from the gas burner 2 for heating and boiling the dilute absorption solution of the high temperature regenerator 1 to a 1st exhaust gas heat recovery equipment 23 arranged between a high temperature heat exchanger 10 of an absorbing solution pipe 11 and a high temperature regenerator 1, and to a 2nd exhaust gas heat recovery equipment 24 arranged between a low temperature heat exchanger 9 and a high temperature heat exchanger 10, and thereby the dilute absorption solution to be transported to the high temperature regenerator 1 from an absorber 7 is increased in temperature. Namely, in the absorption refrigerator of the above construction, the dilute absorption solution at about 40°C (at rated operation, hereinafter the same) discharged from the absorber 7 is heated in the low temperature heat exchanger 9, the 2nd exhaust gas heat recovery equipment 24, the high temperature heat exchanger 10, and the 1st exhaust gas heat exchanger 23, respectively, to be raised up to around 140°C, and flows into the high temperature regenerator 1, therefore, fuel consumption of the gas burner 2 can be saved, 1A Moreover, the absorption refrigerator is so constructed that when the exhaust gas discharged from the gas burner 2 and the dilute absorption solution supplied from the absorber 7 are both at low temperatures, the water vapor contained in the exhaust gas is prevented from being condensed and dewed, by increasing a flow rate of the dilute absorption solution made to flow bypassing the 2nd exhaust gas heat recovery equipment 24 by increasing the opening of a flow control valve 26X, and preventing the exhaust gas from remarkably lowering in temperature by decreasing the heat recovering from the exhaust gas in the 2nd exhaust gas heat recovery equipment 24. SUMMARY OF THE INVENTION However, in the conventional absorption refrigerator described above, even when the temperature of the exhaust gas is lowered to cause condensation and dew of the water vapor contained in the exhaust gas, the temperature is higher than that of the dilute absorption solution discharged from the absorber, and this means the usable heat is not sufficiently recovered yet, therefore, it has been the problem to be solved that the potential heat by the exhaust gas needs to be recovered further depending on the customer to whom the absorption refrigerator is to be delivered. To solve the problem of the prior art described above, the present invention provides, as 1st structure, an absorption refrigerator comprising : a high temperature regenerator which vaporizes and separates a refrigerant by heating and boiling it by a combustion equipment, to obtain vapor of the refrigerant and 2 an intermediate absorption solution from a dilute absorption solution ; a low temperature regenerator which further vaporizes and separates the refrigerant by heating the intermediate absorption solution generated and supplied by said high temperature regenerator with the refrigerant vapor generated by said high temperature regenerator, to obtain the refrigerant vapor and a dense absorption solution ; a condenser which is supplied with the refrigerant solution obtained by heating and condensing the intermediate absorption solution by said low temperature regenerator and which also obtains the refrigerant solution by cooling the refrigerant vapor generated and supplied by said low temperature regenerator ; an evaporator in which the refrigerant solution supplied from said condenser is sprayed on heat conductive tubes and the refrigerant evaporates by absorbing the heat from the fluid flowing in the heat conductive tubes ; an absorber for making the refrigerant vapor generated and supplied by said evaporator absorb the dense absorption solution which is separated and supplied from said low temperature regenerator with the refrigerant vapor into a dilute absorption solution, and supplying it to said high temperature regenerator; a low temperature heat exchanger for performing heat exchange between the dilute absorption solution and the dense absorption solution going in and out of said absorber ; and a high temperature heat exchanger for performing heat exchange between the intermediate absorption solution and the dilute absorption solution going in and out of the high temperature regenerator, wherein said absorption refrigerator is provided with an exhaust gas heat recovery equipment for exchanging heat between the dilute absorption solution made to flow 3 bypassing the low temperature heat exchanger and the exhaust gas discharged from the combustion equipment, and a flow control means for controlling a flow rate of the dilute absorption solution made to flow bypassing the low temperature heat exchanger. In a 2nd structure, the absorption refrigerator having said 1st structure is so structured that it is able to introduce the exhaust gas, which has exchanged heat with the dilute absorption solution passing through the high temperature heat exchanger and/or the low temperature heat exchanger, to the exhaust gas heat recovery equipment. In a 3rd structure, the absorption refrigerator having said 1st or 2nd structure is so structured that at least the exhaust gas heat recovery equipment and the exhaust gas pipe downstream from the exhaust gas heat recovery equipment are formed of steel with improved atmospheric corrosion resistance or stainless steel. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS These and other objects and advantages of the present invention will become clear from the following description with reference to the accompanying drawings, wherein : Fig. 1 is an explanatory drawing showing an embodiment of the present invention ; and Fig. 2 is an explanatory drawing showing the prior art. 4 [Description of Reference Numerals] 1 : high temperature regenerator 2 : gas burner 3 : low temperature regenerator 4 : condenser 5 : hot drum 6 : evaporator 7 : absorber 8: cold drum 9 : low temperature heat exchanger 10: high temperature heat exchanger 11 -13: absorbing solution pipe(s) 14: absorbing solution pumps 4A 15 -17: refrigerant pipe(s) 19: refrigerant pump 20: cold water pipe 21: cooling water pipe 22: exhaust pipe 23: 1st exhaust gas heat recovery equipment 24: 2nd exhaust gas heat recovery equipment 25: 3rd exhaust gas heat recovery equipment 26, 27: distribution control valve 28, 29: temperature sensor 30: controller DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below, mentioning an example of an absorption refrigerator using water as a refrigerant and an aqueous solution of lithium bromide (LiBr) as an absorption solution. An embodiment of the present invention will be explained referring to Fig. 1. In the figure, the reference numeral 1 is a high temperature regenerator constructed so as to vaporize and separate the refrigerant by heating the absorption solution with the thermal power of the gas burner 2 using, for example, city gas as fuel; the reference numeral 3 is a low temperature regenerator; 4 is a condenser; 5 is a hot drum in which the low temperature regenerator 3 and the condenser 4 are incorporated; 6 is an evaporator; 7 is an absorber; 8 is a cold drum in which the evaporator 6 and the absorber 7 are incorporated; 9 is a low temperature heat exchanger; 10 is a high temperature heat exchanger; 11 - 13 are absorbing solution pipes; 14 is an absorbing solution pump; 15-17 are refrigerant tubes; 19 is a refrigerant pump; 20 is a 5 cold water pipe; 21 is a cooling water pipe; 22 is an exhaust pipe through which the exhaust gas discharged from the gas burner 2 passes; 23 is the 1st exhaust gas heat recovery equipment; 24 is the 2nd exhaust gas heat recovery equipment; 25 is a 3rd exhaust gas heat recovery equipment; 26, 27 are distribution control valves; 28 is temperature sensor which is installed in the downstream part of the absorbing solution pipe 13 and detects the temperature of the dense absorption solution having heat radiation by heat exchange with the dilute absorption solution in the low temperature heat exchanger 9; 29 is a temperature sensor which is installed in the exhaust pipe 22 downstream from the 2nd exhaust gas heat recovery equipment 24 and detects the temperature of the exhaust gas having heat radiation by heat exchange with the dilute absorption solution in the 2nd exhaust gas heat recovery equipment; and 30 is a controller which controls the distribution control valve 27 so that the temperature sensor 29 continues detecting a predetermined temperature, for example, 100°C, and also controls the distribution control valve 26 so that the temperature of the dense absorption solution detected by the temperature sensor 28 is maintained at a predetermined temperature slightly higher than the crystallization temperature of the dense absorption solution, for example, at 40°C, and thereby distributes and supplies the dilute absorbing solution to the low temperature heat exchanger 9 and the 3rd exhaust gas heat recovery equipment 25. Moreover, in the absorption refrigerator according to the present invention, the 3rd exhaust gas heat recovery equipment 25 and the exhaust pipe 22 downstream from the 3rd exhaust gas heat recovery equipment 25 are made of steel with improved atmospheric corrosion resistance or rust-proof steel. In the absorption refrigerator of the structure described above, when the dilute absorption solution is heated and boiled in the high temperature regenerator 1 by burning city gas through the gas burner 2, the refrigerant vapor 6 vaporized and separated from the dilute absorption solution, and an intermediate absorption solution increased in the density of the absorption solution due to the separation of the refrigerant vapor are obtained. The refrigerant vapor generated by the high temperature regenerator 1 goes into the low temperature regenerator 3 through the refrigerant tube 15, heating the intermediate absorption solution, which is generated in the high temperature regenerator 1 and goes into the low temperature regenerator 3 via the high temperature heat exchanger 10, and releasing heat to be condensed, and entering the condenser 4. Moreover, the refrigerant vaporized and separated from the intermediate absorption solution by being heated in the low temperature regenerator 3 enters the condenser 4, being heat-exchanged with the water flowing through the cooling water tube 21, to be condensed and liquefied, and entering the evaporator 6 through the refrigerant tube 17 together with the condensed refrigerant supplied from the refrigerant tube 15. The refrigerant solution which has entered the evaporator 6 and has been recovered in the refrigerant solution reservoir thereof is sprayed on the heat conductive tube 20A connected with the cold water pipe 20 by the refrigerant pump 19, and is vaporized by performing heat exchange with the water supplied through the cold water pipe 20, and cools down the water flowing through the heat conductive tube 20A. The refrigerant vaporized in the evaporator 6 enters the absorber 7, and is absorbed into the absorption solution which is heated by the low temperature regenerator 3 to vaporize and separate the refrigerant and is more increased in density, namely, the refrigerant is absorbed into the dense absorption solution which is supplied from the absorbing solution pipe 13 via the low temperature heat exchanger 9 and is sprayed from the above. 7 The absorption solution which has absorbed the refrigerant by the absorber 7 and has been diluted in density, namely, the dilute absorption solution is properly heated in the low temperature heat exchanger 9, the 3rd exhaust gas heat recovery equipment 25, the 2nd exhaust gas heat recovery equipment 24, the high temperature heat exchanger 10, and the 1st exhaust gas heat recovery equipment 23, respectively, and is transported from the absorbing solution pipe 11 to the high temperature regenerator 1. When the absorption refrigerator is operated as described above, the cold water cooled by the vaporization heat of the refrigerant in the heat conductive tube 20A piped inside the evaporator 6 can circularly be supplied to an air conditioning load, not shown, via the cold water pipe 20, therefore, cooling operation such as air conditioning can be carried out. And, in the absorption refrigerator of the above constitution, as well as in the conventional absorption refrigerator illustrated in the fig. 2, the dilute absorption solution at about 40°C in the absorber 7 to be transported to the high temperature regenerator 1 by the absorbing solution pump 14 is properly heated in the low temperature heat exchanger 9, the 3rd exhaust gas heat recovery equipment 25, 2nd exhaust gas heat recovery equipment 24, the high temperature heat exchanger 10, and the 1st exhaust gas heat recovery equipment 23, respectively, up to around 140°C, and is supplied to the high temperature regenerator 1, therefore, fuel consumption of the gas burner 2 can be reduced better than that in a conventional absorption refrigerator which is not provided with the 1st exhaust gas heat recovery equipment 23, the 2nd exhaust gas heat recovery equipment 24, the 3rd exhaust gas heat recovery equipment 25. Namely, the exhaust gas of the gas burner 2 supplied via the exhaust pipe 22 releases heat by exchanging heat with the whole quantity of the dilute 8 absorption solution to be transported from the absorber 7 to the high temperature regenerator 1 by the absorbing solution pump 14 via the absorbing solution pipe 11 in the 1st exhaust gas heat recovery equipment 23, and the potential heat by it is recovered by the dilute absorption solution. On the other hand, in the 2nd exhaust gas heat recovery equipment 24, the distribution control valve 27 is controlled by the controller 30 so that more dilute absorption solution is supplied thereto 24 when the temperature sensor 29 is detecting a temperature higher than the predetermined temperature 100°C and the dilute absorption solution bypassing the 2nd exhaust gas heat recovery equipment 24 is increased in quantity when the temperature sensor 29 is detecting a temperature lower than said predetermined temperature 100°C, and thus an amount of the heat recovering from the exhaust gas is controlled. Therefore, since the exhaust gas temperature is maintained at the predetermined temperature 100°C in the heat recovery from the exhaust gas in the 2nd exhaust gas heat recovery equipment 24, the temperature of the exhaust gas which is exhausted from the gas burner 2 and flowing through the exhaust pipe 22 is maintained 100°C higher than the dew point temperature (the dew point temperature of the combustion exhaust gas when using city gas, namely, natural gas as fuel) even at the time of starting operation and partial load operation when the exhaust gas and the dilute absorption solution are at low temperatures, and the water vapor contained in the exhaust gas is not condensed to generate drain water, and the drain water does not cause a corrosion problem of the member either. Moreover, in the 3rd exhaust gas heat recovery equipment 25, the distribution control valve 26 is controlled by the controller 30 so that a temperature detected by the temperature sensor 28 is maintained at a predetermined temperature slightly higher than, for example, the crystallization 9 temperature of the dense absorption solution, for example, 40°C. Therefore, the heat recovery from the exhaust gas is actively performed within the range in which the temperature of the dense absorption solution flowing into the absorber 7 via the absorbing solution pipe 13 is maintained slightly higher than the crystallization temperature. In that case, even if the temperature of the exhaust gas having heat radiation to the dense absorption solution becomes lower than the dew point of the water vapor contained in the exhaust gas, the 3rd exhaust gas heat recovery equipment 25 itself and the exhaust pipe 22 down stream from the 3rd exhaust gas heat recovery equipment 25 are made of steel with improved atmospheric corrosion resistance or rust-proof steel, therefore, the member will not rust even if they are in contact with the condensate for long hours. Moreover, the present invention is not to be restricted to the embodiments described above, but can be embodied in still other ways without departing from the contemplation described in the scope of the appended claims. For example, instead of the distribution control valves 26, 27, flow control valves may be installed in the absorbing solution pipes in which the 2nd and 3rd exhaust gas heat recovery equipments 24, 25 intervene, or in the absorbing solution pipes bypassing the 2nd and 3rd exhaust gas heat recovery equipments 24, 25, and thereby the absorption refrigerator can be constituted to be controlled by the controller 30 so that suitable quantities of the absorption solution are supplied to the 2nd and 3rd exhaust gas heat recovery equipments 24, 25 as the absorption refrigerator provided with the distribution control valves 26, 27. Moreover, since the water vapor contained in the exhaust gas is sometimes condensed in the 3rd exhaust gas heat recovery equipment 25, the device is preferred to be constructed so that the dilute absorption solution flows 10 through lots of horizontally arranged tubes and the exhaust gas flows outside of the tubes in the vertical direction, in order to facilitate draining the condensed water from the 3rd exhaust gas heat recovery equipment 25. Moreover, the absorption refrigerator may exclusively be used for cooling operation of air conditioning or the like as described above, and may also be arranged so as to be able to perform heating operation of air conditioning by arranging piping connection permitting to directly supply the cold drum 8 with the refrigerant vapor heat-generated by the high temperature regenerator 1 and the absorption solution from which the refrigerant vapor has been separated by vaporization, heating the dilute absorption solution by the gas burner 2 without flowing the cooling water through the cooling water pipe 21, and circularly supplying a load with water heated, for example, at about 55°C in the heat conductive tube 20A of the evaporator 6 through the cold water pipe 20 (preferred to be called a hot water pipe when hot water circulates). Further, as a fluid to be supplied to an air-conditioning load by cooling it by the evaporator 6, not only water or the like may be supplied without phase change as described in the above embodiment, but also fluorocarbon or the like may be supplied with phase change so as to be able to transport heat utilizing latent heat. 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 modifications may be made by those skilled in the art without departing from the scope of the invention as set forth in the appended claims. Advantages of the Invention According to the present invention as explained above, it is possible to recover most of the usable potential heat by the exhaust gas. Moreover, since 11 the substantial parts are made of steel with improved atmospheric corrosion resistance or rust-proof steel, the member will not rust even if it is in contact with the condensate for long hours. Moreover, it is also possible to avoid considerable increase in cost by limiting use of expensive steel products. 12 WE CLAIM: 1. An absorption refrigerator comprising : a high temperature regenerator which vaporizes and separates a refrigerant by heating and boiling it by a combustion equipment, to obtain vapor of the refrigerant and an intermediate absorption solution from a dilute absorption solution ; a low temperature regenerator which further vaporizes and separates the refrigerant by heating the intermediate absorption solution generated and supplied by said high temperature regenerator with the refrigerant vapor generated by said high temperature regenerator, to obtain the refrigerant vapor and a dense absorption solution ; a condenser which is supplied with the refrigerant solution obtained by heating and condensing the intermediate absorption solution by said low temperature regenerator and which also obtains the refrigerant solution by cooling the refrigerant vapor generated and supplied by said low temperature regenerator ; an evaporator in which the refrigerant solution supplied from said condenser is sprayed on heat conductive tubes and the refrigerant evaporates by absorbing the heat from the fluid flowing in the heat conductive tubes ; an absorber for making the refrigerant vapor generated and supplied by said evaporator absorb the dense absorption solution which is separated and supplied from said low temperature regenerator with the refrigerant vapor into a dilute absorption solution, and supplying it to said high temperature regenerator; a low temperature heat exchanger for performing heat exchange between the dilute absorption solution and the dense absorption solution going in and out of 13 said absorber ; and a high temperature heat exchanger for performing heat exchange between the intermediate absorption solution and the dilute absorption solution going in and out of the high temperature regenerator, wherein said absorption refrigerator is provided with an exhaust gas heat recovery equipment for exchanging heat between the dilute absorption solution made to flow bypassing the low temperature heat exchanger and the exhaust gas discharged from the combustion equipment, and a flow control means for controlling a flow rate of the dilute absorption solution made to flow bypassing the low temperature heat exchanger. 2. An absorption refrigerator as claimed in claim 1, wherein said refrigerator is constructed so as to be able to introduce the exhaust gas which has heat-exchanged with the dilute absorption solution passing through the high temperature heat exchanger and/or the low temperature heat exchanger, into the exhaust gas heat recovery equipment. 3. An absorption refrigerator as claimed in claim 1 or 2, wherein at least the exhaust gas heat recovery equipment and the exhaust pipe downstream from said exhaust gas heat recovery equipment are made of steel with improved atmospheric corrosion resistance or rust-proof steel. 14 15 4. An absorption refrigerator substantially as herein described, particularly with reference to the accompanying drawings. The purpose of the present invention is to improve the thermal efficiency of an absorption refrigerator. The absorption refrigerator is provided with the refrigerant heat recovery equipment 11 for performing heat exchange between the refrigerant which radiated heat and is condensed by heating the intermediate absorption solution in the low temperature regenerator 3 and is introduced into the condenser 4 through the refrigerant pipe 20, and a part of the dilute absorption solution discharged from the absorber 7 and sent to the high temperature regenerator 1 bypassing the low temperature heat exchanger 9, and the rotation speed of the absorption solution pump 18 is controlled by the controller 33 so that the temperature of the dense absorption solution detected by the temperature sensor 32 is higher than a predetermined temperature, for example 40°C.

Documents:

00096-kol-2003-abstract.pdf

00096-kol-2003-claims.pdf

00096-kol-2003-correspondence.pdf

00096-kol-2003-description(complete).pdf

00096-kol-2003-drawings.pdf

00096-kol-2003-form-1.pdf

00096-kol-2003-form-18.pdf

00096-kol-2003-form-2.pdf

00096-kol-2003-form-3.pdf

00096-kol-2003-form-5.pdf

00096-kol-2003-g.p.a.pdf

00096-kol-2003-letters patent.pdf

00096-kol-2003-priority document others.pdf

00096-kol-2003-priority document.pdf

00096-kol-2003-reply f.e.r.pdf

96-KOL-2003-FORM-27.pdf