JPH10204589A - High temperature regenerator for air cooled absorption type cooling and warming machine for water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a regenerator causing neither pitting corrosion nor stress corrosion cracking even under an environment of a liquid absorbent in the neighborhood of 200 deg.C and suitable for an absorption type cooling and warming machine for water for general domestic use, requiring size reduction and high efficiency. SOLUTION: In the high temp. regenerator for an air cooled absorption type cooling and warming machine for water, water is used as a refrigerant and a liquid absorbent containing LiBr, LiI, LiCl, and LiNO3 as essential components and having <=50 mass % LiBr concentration is used. In this case, an austenitic stainless steel, which has a composition consisting of <=0.08% C, 1.0%-5.0% Si, <=1.0% Mn, <=0.045% P, <=0.005% S, 16.0-25.0% Cr, 6.0-20.0% Ni, <=0.1% Al, 0.005-0.35% N, and the balance essentially Fe, containing, if necessary, 0.5-3.0% Cu and/or 0.5-3.0% Mo, and satisfying (Cr+0.5Ni+3Si+3 Mo-5Al)>=30 and is subjected to No.80-600 count polishing finish or to mixed- acid finishing in an aqueous solution of HF-HNO3 of 1-20% HF concentration, is used as a structural material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is manufactured by Ni brazing and has LiBr, LiI, LiCl, and LiN as main components.
The present invention relates to a high-temperature regenerator for an air-cooled absorption type chiller / heater using an absorbent containing O ₃ .

[0002]

2. Description of the Related Art As a cooling and heating system that does not use environmentally harmful CFCs as a refrigerant, an absorption type chiller / heater using an aqueous solution of high-concentration alkaline LiBr having a concentration of 50% by mass or more as an absorbent has attracted attention. In the absorption cooling and heating system, for example, as shown in FIG.
The Br aqueous solution 6 is separated into the rich absorbing liquid 11 and the steam refrigerant 5. The steam refrigerant 5 enters the condenser 1, is cooled by the cooling medium 7, condenses into a liquid refrigerant 8, and enters the evaporator 3. The heat of condensation generated here is released to the outside through a cooling medium 7 by a cooling tower or the like. Liquid refrigerant 8
Takes the latent heat from the load medium 10 in the evaporator 3 and enters the absorber 4 as a steam refrigerant 5 ′. The load medium 10, which has been deprived of heat and cooled, is circulated in the cooling room 9, and cools by depriving the indoor heat. On the other hand, the concentrated absorbent 11 concentrated in the high-temperature regenerator 2 enters the absorber 4 via the solution heat exchanger 20, absorbs the steam refrigerant 5 'flowing from the heat exchanger 3, and becomes the lean absorbent 12. , And returns to the high temperature regenerator 2 via the solution heat exchanger 20. The absorbed heat generated by the absorption of the steam refrigerant 5 'is radiated to the outside via the cooling medium 7'.

[0003] The high-temperature regenerator 2 used in this absorption type cooling and heating system has, for example, a structure as shown in FIG. The high-temperature regenerator 2 includes a plate-type heat exchanger 14 in which a lean absorbent flow path and a combustion exhaust gas flow path are alternately stacked. The lean absorbing liquid 12 is sent into the plate heat exchanger 14 from the inlet 16 and is heated by the combustion exhaust gas G sent as a heat source to be separated into a steam refrigerant and a rich absorbing liquid. The vapor refrigerant flows from the vapor outlet 17 to the condenser 1, and the rich absorbent flows from the absorbent outlet 18 to the absorber 4.
Will be sent to The combustion exhaust gas G is sent out from the exhaust port 15. The plate-type heat exchanger 14 has a brazing structure in order to prevent the leakage of the dilute absorbing liquid and the intrusion of the atmosphere, and is brazed to the frame 13 at the brazing portion 19.

[0004] Commercial large-scale machines and medium-sized machines of 10 refrigeration tons or more, which have already been put into practical use, use regenerators made of carbon steel, cupronickel, or the like as a structural material, and use high-concentration alkaline water containing LiBr as a main component. Approximately 150
Heat to ° C. However, in applications for general households of several refrigeration tons, further miniaturization and higher performance are required, so the cooling of water vapor and absorbing liquid in the condenser and absorber is switched from conventional water cooling to air cooling, and It is necessary to improve operation efficiency. Therefore, in order to commercialize a small air-cooled absorption type air conditioner, it is necessary to raise the operating temperature of the regenerator to a maximum of about 200 ° C., and it is difficult to obtain sufficient corrosion resistance with conventional materials. Therefore, the use of stainless steel in consideration of corrosion resistance and cost has been studied instead of conventional materials.

[0005] Ferritic stainless steel for absorption type water heaters has a corrosion resistance of A in high concentration halides.
Japanese Patent Publication No. 6-37692 and Japanese Patent Publication No. 5-3 describe that the improvement can be achieved by the addition of 1, Co, Cr, Ni, Mo, Cu and the like.
No. 4419, and the like. For austenitic stainless steel, Cr, Ni, Mo, Cu, S
It has been found that the addition of i or the like is effective in improving the corrosion resistance.
-298237. JP-A-7-3
No. 5,433, introduces that Si-added steels exhibit excellent corrosion resistance as materials for absorption type air conditioners, regardless of whether they are ferritic or austenitic.

[0006]

SUMMARY OF THE INVENTION In order to make an absorption type air conditioner suitable for general household use of several refrigeration tons, the regenerator temperature must be reduced to improve the operation efficiency of a high temperature regenerator. It is necessary to raise the temperature to about 200 ° C. In addition, in order to improve the performance of the regenerator, it is preferable that the heat exchange portion has a complicated shape. Brazing is suitable for assembling a heat exchanger having a heat exchange portion having a complicated shape.
Among them, nickel brazing with BNi-5 is most suitable from the viewpoint of ensuring corrosion resistance and joining strength in an absorbing liquid environment. As for the absorbing solution, about 60% concentration of Li
In the case of using a Br absorbing solution as a main component, there is a disadvantage that when the device is operated at 200 ° C., crystallization of the absorbing solution occurs at room temperature cooling. Therefore, a four-component high-concentration absorbing solution of LiBr—LiI—LiCl—LiNO ₃ has been required.

[0007] Such an absorption type air conditioner for general households.
Japanese Patent Publication No. 6-37692, Japanese Patent Publication No.
Ferritic stainless steels such as Japanese Patent No.
Used for coarsening of crystal grains by nickel brazing
Can not. On the other hand, austenitic stainless steel
Nickel brazing with BNi-2, BNi-5, etc.
It is possible. However, BNi-2 is LiBr-LiI
-LiCl-LiNO _Three In a four-component high-concentration absorbent
Insufficient corrosion resistance. BNi-5 contains Si.
For austenitic stainless steels with an amount of 1% by mass or more
Does not show sufficient bonding strength. Further, LiBr-Li
I-LiCl-LiNO_Three Use a four-component absorption solution
In the case, I present in the absorption liquid_Two But the high temperature regenerator
High temperature in harsher corrosive environment than before
The regenerator is exposed. In this regard, absorption air conditioning for general households
Stainless steel used as regenerator structural material for
Having corrosion resistance that surpasses conventionally disclosed steel materials
Required.

[0008] The present invention has been devised to solve such a problem, and employs an alloy design having a specific correlation between the alloy components and a specific polishing finish or mixed acid finish. By using austenitic stainless steel treated with
An object of the present invention is to provide a high-temperature regenerator of an air-cooling absorption chiller / heater that exhibits sufficient corrosion resistance even in a quaternary high-concentration absorbing solution of r-LiI-LiCl-LiNO ₃ and sufficiently withstands high-temperature operation.

[0009]

The high-temperature regenerator according to the present invention comprises:
In order to achieve the object, water is used as a refrigerant, and the main component is Li.
A high-temperature regenerator of an air-cooled absorption-type chiller / heater using a quaternary high-concentration absorbing solution of Br, LiI, LiCl, LiNO ₃ and a LiBr concentration of 50% by mass or less, wherein C: 0.0
8% by mass or less, Si: 1.0 to 5.0% by mass, Mn:
1.0 mass% or less, P: 0.045 mass% or less, S:
0.005% by mass or less, Cr: 16.0 to 25.0% by mass, Ni: 6.0 to 20.0% by mass, Al: 0.1% by mass or less, N: 0.005 to 0.35% by mass %, The balance being substantially Fe, (Cr + 0.5Ni + 3Si-5Al) ≧
An austenitic stainless steel having a composition satisfying 30 and being polished and finished with 80-600 count is used as a structural material such as a heat exchanger member and a frame.

The austenitic stainless steel used in the present invention is (Cr + 0.5Ni + 3Si + 3Mo-5A)
l) Under conditions that satisfy ≧ 30, Cu: 0.5-3.
0% by mass and / or Mo: 0.5 to 3.0% by mass. Instead of the polishing finish, Si which is concentrated as an oxide on the surface of the steel material by the mixed acid finishing in an HF-HNO ₃ aqueous solution having an HF concentration of 1 to 20% by mass may be removed.

[0011]

In the regenerator of the absorption type air conditioner, high concentration LiBr
-LiI-LiCl-LiNO _Three Concentration 5 whose main component is
0% by mass or more of the absorbing solution is used.
Heat to high temperature. At this time, the inside of the refrigerator is
Starts operation in a sealed state, accelerating the cathode reaction
The amount of oxygen to be made is small. However, I_Two 
Is released into the gas phase, so that it can be compared with a conventional absorbent environment
And the gas phase is exposed to a more severe corrosive environment. Inventors
Is the gas phase in a highly absorbent environment due to the increase of Si.
Corrosion resistance and stress corrosion cracking resistance of the
Suppress pitting growth by establishing a specific relationship between gold components
Excellent corrosion resistance even in harsh corrosive environments
Austenitic stainless steel
And found. Furthermore, an oxide is formed on the stainless steel surface.
Concentrated Si (hereinafter referred to as Si concentrated layer)
Or chemical removal, nickel brazing
A brazed joint with good joining strength can be obtained,
Elucidating that it can withstand the use of a heater as a regenerator
Was. Austenitic system with the specified composition
Removal of the Si-enriched layer on the surface of cold-rolled stainless steel sheet
Plates, tubes, fins, and fins for heat exchangers
When used as a high temperature regenerator
High concentration LiBr-Li whose high temperature reaches about 200 ° C
I-LiCl-LiNO_Three Severe corrosive environment
Pitting resistance and stress corrosion cracking resistance are improved
A regenerator for an absorption type air conditioner is obtained.

Hereinafter, alloy components, contents, and the like included in the austenitic stainless steel used in the present invention will be described. C: 0.08% by mass or less A strong alloy component that stabilizes austenite, and does not significantly affect stress corrosion cracking resistance and pitting corrosion resistance. However, the upper limit of the C content was set to 0.08% by mass in order to increase the intergranular corrosion susceptibility of the weld.

Si: 1.0-5.0% by mass A stable film is formed on the surface of a steel material and a high concentration of Li
Pitting resistance of the gas phase portion in the Br-LiI-LiCl-LiNO ₃ quaternary absorbing liquid environment, it exhibits a function of improving the stress corrosion cracking resistance. Such an effect becomes remarkable with 1.0% by mass or more of Si. Furthermore, the stress corrosion cracking resistance improved by the addition of Si is not impaired even when a certain amount of Mo is added. However, since it is a strong ferrite-forming element, it is necessary to add a large amount of Ni to stabilize the austenite phase with an increase in the Si content, thereby increasing the cost of the steel material. Therefore, in the present invention, the upper limit of the Si content is set to 5.0% by mass in order to minimize the amount of expensive Ni added.

Mn: 1.0% by mass or less Sulfide, which is likely to be a starting point of corrosion, is formed and deteriorates pitting corrosion resistance and crevice corrosion resistance. Therefore, the smaller the Mn content, the better. However, if the Mn content is excessively reduced, the raw material cost increases, and the production cost increases. Therefore, in the present invention, the upper limit of the Mn content is set to 1.0% by mass in consideration of economy. P: 0.045% by mass or less An element that has an adverse effect on productivity such as hot workability and stress corrosion cracking resistance. In the present invention, the upper limit of the P content is set to 0.045% by mass, which is allowed for ordinary stainless steel. S: 0.005% by mass or less Reacts with Mn in steel to form a sulfide that is harmful to pitting corrosion resistance. Therefore, the S content is preferably as low as possible. In the present invention, the upper limit of the S content is set to 0.005% by mass.

Cr: 16.0 to 25.0 mass% Cr is an indispensable alloy component in stainless steel.
Particularly high concentration LiBr-LiI-LiCl-LiNO ₃
To demonstrate excellent corrosion resistance in a quaternary absorbent environment,
16.0% by mass or more of Cr is required. Corrosion resistance is C
The higher the r content, the better. However, with a large amount of Cr, the amount of Ni necessary for maintaining the austenite phase increases, and the manufacturability and workability also deteriorate. Therefore, in the present invention, the upper limit of the Cr content is set to 25.0% by mass. Ni: 6.0 to 20.0% by mass Ni is a main alloy component for maintaining the austenite phase, and at least 6% by mass of Ni is required. However, 2
If the content exceeds 0% by mass, a large amount of expensive Ni is consumed, so that the cost of steel material increases. Therefore, in the present invention, the Ni content is set in the range of 6.0 to 20.0% by mass. Ni effectively acts to improve the pitting corrosion resistance in this range. Particularly in areas where pitting corrosion resistance is required,
It is preferable to use a steel material having a Ni content of 10% by mass or more.

Al: 0.1% by mass or less Al acts not only as a deoxidizing agent during smelting, but also has a function of concentrating on the surface of stainless steel to strengthen a passive film and improving corrosion resistance in neutral chloride. However, in the gas phase portion of the high-temperature regenerator, which is a corrosive environment due to acidic condensed water containing I ₂ , the Al film is preferentially dissolved and becomes a starting point of pitting. In this regard, the smaller the amount of Al added, the better. In the present invention, the upper limit is set to 0.1% by mass. N: 0.005 to 0.35 mass% In addition to being a strong austenite-forming element, an austenitic alloy is an effective alloy component for improving corrosion resistance. N
The effect of addition becomes significant at 0.005% by mass or more. However, when a large amount of N exceeding 0.35% by mass is added,
Not only is the manufacturability and workability deteriorated, but also the stress corrosion cracking resistance is reduced.

Cu: 0.5 to 3.0% by mass An alloy component added as required, and has an effect of improving stress corrosion cracking resistance in an aqueous solution containing a halide. The effect of improving the stress corrosion cracking resistance appears at a Cu content of 0.5% by mass or more, and is remarkably improved as the Cu content increases. However, when the Cu content is 3.0% by mass, the improvement effect is saturated, and on the contrary, the hot workability tends to decrease. Mo: 0.5 to 3.0% by mass An alloy component added as necessary, and has an effect of strengthening a passive film and improving pitting corrosion resistance in a high-concentration halide aqueous solution. In order to sufficiently exhibit the effect of adding Mo, it is effective to add 0.5% by mass or more, preferably 0.7% by mass or more of Mo. However, since Mo is an expensive element, the upper limit of the Mo content was set to 3.0% by mass in the present invention.

(Cr + 0.5Ni + 3Si + 3Mo-5Al) ≧ 30 In a high-temperature regenerator using a quaternary absorption solution of LiBr—LiI—LiCl—LiNO ₃ , I ₂ is separated into a gas phase and the gas phase of the regenerator Pitting is apt to occur in stainless steel hitting As a result of investigating the influence of each alloy component on the pitting corrosion, the present inventors have found that the X value defined by X = Cr + 0.5Ni + 3Si + 3Mo-5Al is maintained at 30 or more, as described in Examples described later. It has been found that it is effective to do so. In the case of a steel type not containing Mo,
The Mo term is excluded from the conditional expression described above. The detailed reason why the X value improves the pitting resistance is not clear,
It is presumed that the above adjustment causes the autocatalytic growth of pitting corrosion to be suppressed. In other words, pitting corrosion of stainless steel has a value generally called critical pitting depth. For pitting corrosion below the critical value, the passivation film is repaired by re-passivation, and pitting corrosion above the critical value is autocatalytic. Grow up. This self-catalytic pit growth
It can be suppressed by setting the X value to 30 or more. On the other hand, 3
When the X value is less than 0, growth pitting occurs, and the pitting becomes large with time.

Polishing finish: 80-600 When the cold-rolled stainless steel sheet having the above composition is used as a structural material of a regenerator, it is advantageous in terms of corrosion resistance, steel sheet productivity, workability and cost. However, when the cold-rolled stainless steel sheet is brazed with BNi-5, the 2B, 2D product material of steel containing 1.0% by mass or more of Si has a Si-enriched layer formed on the surface, so that the joining is performed. A brittle nickel compound is formed at the interface. Therefore, a brazed joint having sufficient joining strength cannot be obtained. Then, the present inventors came up with a method of mechanically removing the Si-concentrated layer on the surface of the steel material by polishing and finishing the surface of the stainless steel. When brazing stainless steel from which the Si-enriched layer has been removed from the surface, there is no generation of brittle nickel compounds due to the Si-enriched layer, and the brazing joint has sufficient joint strength to be used as a heat exchanger Is obtained. S by polishing finish
The removal of the i-concentrated layer becomes remarkable by polishing of No. 600 or less. The joining property of brazing improves as the polishing grain becomes coarser. However, if the number is less than 80, sufficient corrosion resistance cannot be obtained.

Mixed acid finishing: H having an HF concentration of 1 to 20% by mass
F-HNO ₃ aqueous solution The Si-concentrated layer on the stainless steel surface is also removed by pickling using an HF-HNO ₃ aqueous solution. HF-HNO
₍₃ ) HF in the aqueous solution has the property of dissolving the Si-concentrated layer on the stainless steel surface, and HNO ₃ has the function of passivating the surface of the stainless steel in which the Si-concentrated layer is dissolved and strengthening the film. Among them, HF with an HF concentration of 1 to 20% by mass
The HNO ₃ aqueous solution reduces the Si-concentrated layer on the stainless steel surface to a level that exhibits sufficient bonding strength as a heat exchanger, as described in Examples described later. The effect of reducing the Si-concentrated layer becomes particularly remarkable when the HF concentration is 3% by mass or more. However, since an increase in the HF concentration causes deterioration of equipment, deterioration of the working environment, problems in cost, and the like, the upper limit of the HF concentration is set to 20% by mass in the present invention.

The LiBr concentration of the absorbing solution: not more than 50% by mass The absorbing solution conventionally used has a main component of LiBr having a concentration of not less than 50% by mass. However, in order to improve the performance, it is necessary to increase the concentration of the absorbing solution, and when the solution is cycled with the absorbing solution, the concentrated absorbing solution is crystallized in a low temperature part. In order to prevent crystallization of the absorbing solution, it is desirable to make the absorbing solution into a multi-component system, especially a four-component system of LiBr—LiI—LiCl—LiNO ₃ and a LiBr concentration of 50% by mass or less. It was found that it was effective to

[0022]

EXAMPLE A stainless steel having the components shown in Table 1 was melted and subjected to hot rolling, pickling, cold rolling and intermediate annealing to obtain a sheet thickness of 0.3 mm.
Was produced. In Table 1, Group A indicates a ferritic stainless steel, Group B indicates an austenitic stainless steel having a low Si content, and Group C indicates an austenitic stainless steel satisfying the conditions specified in the present invention.

[0023]

Stainless steel plates B-1, B-2, C-1
Cut out to a size of 5 to 10 mm x 75 mm, dry-grind the surface with No. 500 emery paper, and bend radius 8 m
m U-bend test pieces were prepared. LiBr: LiI: L
iCl: LiNO ₃ = 1: (0.5 to 0.63):
(0.2 to 0.25): gas phase and liquid phase of an autoclave containing a quaternary absorbent having a composition of (0.2 to 0.25) and a concentration of 63% by mass and an alkalinity of 0.3 N Each test piece was set in the section, and the autoclave was sealed. In this state, the effect of the addition of Si on the stress corrosion cracking resistance of stainless steel was investigated by holding the absorbing solution at 200 ° C. for 2000 hours. As a result, in the stainless steels B-1 and B-2 having a small Si content, stress corrosion cracking occurred in the test piece exposed to the gas phase after 1000 hours. On the other hand, in the stainless steels C-1 to C-5 containing the amount of Si specified in the present invention, no stress corrosion cracking was observed in any of the test pieces exposed to the gas phase part and the liquid phase part. Was. As is clear from this comparison, by using a stainless steel to which 1.0% by mass or more of Si is added as a structural material, a regenerator excellent in stress corrosion cracking resistance in both the gas phase and the liquid phase can be obtained. confirmed.

Further, the corrosion resistance of each stainless steel was examined by the following test. 150mm x 30 from each stainless steel
A mm test piece was cut out, dry polished with No. 500 emery paper, degreased with an aqueous solution of MgO, and dried overnight. Each test piece after the drying treatment was placed in an autoclave containing the same absorbent as in the stress corrosion cracking test, and each test piece was half-immersed in the absorbent so that the immersion part depth was about 30 mm. The autoclave was closed under reduced pressure of 1.5 mmHg, and the absorbing solution was heated and maintained at 150 ° C. for 480 hours.
After heating and holding, remove the test specimen from the autoclave,
Each test piece was immersed in a 30% HNO ₃ aqueous solution maintained at 0 ° C. to remove corrosion products, and the maximum pit depth was measured.
As shown in FIG. 3 showing the measurement results, X = Cr + 0.
It was found that there was a close relationship between the X value defined by 5Ni + 3Si + 3Mo-5Al and the maximum pit depth. That is, when the X value was adjusted to 30 or more, the maximum pit depth was 0.02 mm or less, and the pit portion was repaired by re-passivation. On the other hand, when the X value is less than 30, the pit has a growth pit having a maximum pit depth exceeding 0.02 mm.

Next, the effect of the mixed acid finish on the brazing properties was investigated as follows. Sheet thickness 1 with composition C-4
mm of stainless steel cold-rolled steel tube at 55 ° C
Tensile test immersed in an aqueous solution of HF + 9% by mass HNO ₃ (X: 0.5% by mass, 2.5% by mass, 5% by mass, 10% by mass) for 30 seconds and brazed with BNi-5 in accordance with JIS Z3192 Pieces were made. Tensile tests were performed for each mixed acid having a different HF concentration at n = 10, and the relationship between the minimum value of the breaking stress obtained in the tensile test and the HF concentration was determined. FIG.
As can be seen from the investigation results, the higher the HF concentration of the mixed acid, the higher the breaking stress. The breaking stress required for the heat exchange part of the regenerator is 200 MPa or more, and it can be seen that it is necessary to perform mixed acid finishing with an HF concentration of 1% by mass or more to satisfy this requirement. Above all, HF concentration of 3
When the content was equal to or more than the mass%, the breaking stress was greatly improved.

Further, stainless steel sheets B-1, B-2, C
After applying the finishing shown in Table 2 to each of No. -4, a plate heat exchanger 14 was produced. Then, the high temperature regenerator was assembled by brazing the heat exchanger 14 to the frame 13 using BNi-5. The obtained high-temperature regenerator was subjected to a pressure test at a maximum pressure of 10 atm. As can be seen from the test results in Table 2, in the regenerator made of stainless steel C-4 having a Si content of 1% by mass or less, 0.5% by mass HF was used.
Test No. 4 finished with mixed acid with +9 mass% HNO ₃ aqueous solution
In the regenerator, peeling was observed at the brazing point. But,
Test No. 3 of 400th polishing finish in C-4, Test No. 5 of mixed acid finish with 2.5% by mass HF + 9% by mass HNO ₃ , or B-1, B-2 with Si content of less than 1% by mass
In the results of the pressure tests of the other regenerators manufactured in the above, no abnormality such as breakage or peeling was detected in any of the brazed joints, and the heat exchanger 14 was joined to the frame 13 with good joining strength.

[0028]

Test Nos. 1-3, 5 with good withstand voltage test results
The regenerator was subjected to a durability test at the maximum temperature of 190 ° C. for 2,000 hours using the same absorbent as in the stress corrosion cracking test (test numbers 6 to 9). As shown in Table 3 showing the test results, in the regenerator made of stainless steel B-1 having an X value of less than 30, pitting occurred in the gas phase of the heat exchanger. On the other hand, in the regenerator made of other steel types, generation of pitting corrosion was not observed. In addition, stainless steel B-1,
In the regenerator made of B-2, stress corrosion cracking occurred in the gas phase of the heat exchanger, but the regenerator made of stainless steel C-4 having a Si content of 1% by mass or more had good stress corrosion resistance. It exhibited cracking properties. As is evident from this contrast, regenerators made of stainless steel according to the present invention cause troubles even when operated in severe corrosive environments exposed to quaternary absorbents heated to high temperatures. It can be seen that they can withstand long driving without any problem.

[0030]

[0031]

As described above, the regenerator of the absorption type air conditioner of the present invention contains a specific amount of Cr, Ni, Si and, if necessary, Mo, Cu, and X = Cr + 0.5Ni + 3.
An austenitic stainless steel having a composition designed so that the X value defined by Si + 3Mo-5Al is 30 or more and having a surface-enriched layer removed by polishing or mixed acid finishing is used as a structural material. . The use of the structural materials specified in this way has improved the reproducer's manufacturability, corrosion resistance, and stress corrosion cracking resistance, which have been problems in downsizing and improving the performance of absorption-type water heaters and cold water heaters. Brazing forms a brazed joint with good joint strength. As a result, it is possible to reduce the size and performance of the absorption chiller / heater to the order of several refrigeration tons for ordinary households.

[Brief description of the drawings]

Fig. 1 Conceptual diagram of absorption type air conditioning system

FIG. 2 is a diagram showing the internal structure of a regenerator used in an absorption type air conditioning system.

FIG. 3 X = Cr + 0.5Ni + 3Si + 3Mo-5
Graph showing that there is a close relationship between the X value defined by Al and the maximum pit depth

FIG. 4 is a graph showing the effect of the HF concentration used in the pickling finish on the minimum value of the breaking stress of the brazed part.

[Explanation of symbols]

1: Condenser 2: High temperature regenerator 3: Evaporator 4:
Absorber 5, 5 ': Steam refrigerant 6: LiBr aqueous solution 7, 7': Cooling medium 8: Liquid refrigerant 9: Cooling room 10: Load medium 11: Rich absorption liquid 12: Dilute absorption liquid 13: Frame 14: Heat exchanger 15: Exhaust port
16: Absorbent inlet 17: Vapor outlet 18: Absorbent outlet 19: Brazing part 20: Solution heat exchanger G: Combustion exhaust gas

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yukihiro Kawabata 4976 Nomura Minami-cho, Shinnanyo-shi, Yamaguchi Nisshin Steel Technical Research Institute (72) Inventor Akinori Nagamatsutani 1370 Koyasucho, Hamamatsu-shi, Shizuoka Stock Association In-house (72) Inventor Jun Kuroda 1370 Koyasu-cho, Hamamatsu-shi, Shizuoka Pref. Yazaki Sogo Co., Ltd.

Claims (3)

[Claims] 1. A method according to claim 1, wherein water is used as a refrigerant, and the main components are LiBr and Li.
A high-temperature regenerator of an air-cooled absorption-type water-cooled water heater using an absorbing solution of I, LiCl, LiNO ₃ and a LiBr concentration of 50% by mass or less, wherein C: 0.08% by mass or less, Si: 1.
0 to 5.0% by mass, Mn: 1.0% by mass or less, P: 0.
045 mass% or less, S: 0.005 mass% or less, Cr:
16.0-25.0% by mass, Ni: 6.0-20.0% by mass, Al: 0.1% by mass or less, N: 0.005-0.
35 mass%, the balance being substantially Fe, (Cr + 0.5N
i + 3Si-5Al) ≧ 30, and 8
A high-temperature regenerator for an air-cooling absorption chiller / heater using austenitic stainless steel polished and finished with a count of 0 to 600. 2. The method according to claim 1, wherein water is used as a refrigerant and the main components are LiBr and Li.
A high-temperature regenerator of an air-cooled absorption-type water-cooled water heater using an absorbing solution of I, LiCl, LiNO ₃ and a LiBr concentration of 50% by mass or less, wherein C: 0.08% by mass or less, Si: 1.
0 to 5.0% by mass, Mn: 1.0% by mass or less, P: 0.
045 mass% or less, S: 0.005 mass% or less, Cr:
16.0-25.0% by mass, Ni: 6.0-20.0% by mass, Al: 0.1% by mass or less, N: 0.005-0.
35 mass%, the balance being substantially Fe, (Cr + 0.5N
i + 3Si-5Al) ≧ 30.
A high-temperature regenerator for an air-cooling absorption type chiller / heater using austenitic stainless steel as a structural material which has been subjected to a mixed acid finish in an aqueous HF-HNO ₃ solution having an F concentration of 1 to 20% by mass. 3. (Cr + 0.5Ni + 3Si + 3Mo−)
5Al) Under conditions satisfying ≧ 30, Cu: 0.5 to
The high-temperature regenerator for an air-cooling absorption chiller / heater according to claim 1 or 2, wherein the structural material is an austenitic stainless steel containing 3.0% by mass and / or Mo: 0.5 to 3.0% by mass.