JPH1144466A - Ammonia absorption type heat pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ammonia absorption type heat pump, high in reliability and employing rust preventive, not contaminating environment, by a method wherein a primary circuit is constituted by welding iron base materials while the rust preventive, constituted of the combination of at least two kinds or more of a nitrite, a nitrate, and a hydroxide of a metal and the like, is employed. SOLUTION: A suction tank 10, equipped with a filter 8, provided at the lower part of inside of the tank, and a gas reservoir 9, provided at the upper part of inside of the tank, is connected to the outlet port of an absorber 7, while a valve 11 is provided at the upper part of the tank 10. On the other hand, a liquid guide plate 12 for guiding a liquid from the absorber 7 into the filter 8 is provided above the filter 8 in the tank 10. In this case, a primary circuit is constituted by welding iron base materials through welding and nickel brazing while at least two kinds or more of combination of a rust preventive, effective for the iron base materials, and another rust preventive, effective for the nickel brazing material, among a nitrite, a nitride, a boride, a hydroxide of a metal, molybdate, phosphate, phosphotungusian, silicate and silicagel, is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ammonia-absorbing heat pump for home cooling, heating and hot water supply equipment using ammonia and water as a working medium.

[0002]

2. Description of the Related Art Conventionally, this type of ammonia absorption type heat pump is not for domestic use but is for business use. A generator / rectifier having a generator and a rectifier integrated with each other, a condenser, and a supercooler are known. Vessel, evaporator, solution heat exchanger, absorber and solution pump,
And the like are formed by welding with iron and an iron alloy such as steel. In addition, a dichromate such as potassium dichromate was added to the primary circuit together with the ammonia water as a rust preventive. Then, due to the presence of the dichromate, a protective layer (passive film) of iron and chromium oxide is formed on the surface of the primary circuit that is in contact with the aqueous ammonia, and the presence of the protective layer causes the formation of an iron-based material. Oxidation of the material was prevented to suppress hydrogen generation.

In the absence of a rust preventive, not only loss of iron due to corrosion but also oxidation of a metal containing iron generates hydrogen gas, which hinders proper operation of the cycle.

[0004]

However, when dichromate is used as in the above-mentioned conventional art, there is a possibility that health may be impaired. The US Environmental Protection Agency has banned the use of chromium compounds in systems open to the atmosphere. Of course, although the ammonia absorption heat pump is a closed system, the working medium may be scattered to some extent from the system into the atmosphere during sampling of the working medium, during the manufacturing process, and during handling and injection.

[0005] Further, chromium in dichromate is strictly regulated by effluent standards as a substance that significantly contaminates the natural environment, and assuming leakage from the system or disposal at the end of its service life, the handling of chromium is difficult. The above is subject to great restrictions, and the fact is that it is no longer actually used.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and exhibits a rust-preventive effect by synergistic effects by combining two or more kinds of rust-preventive agents having little toxicity and high safety. It is something to do. In addition, by treating the inner surface of the primary refrigerant circuit in advance,
This ensures that a dense rust-proof coating is formed. Further, the corrosion resistance is further improved by using stainless steel having a low nickel content and a nickel brazing material having a high chromium content.

According to the above invention, a highly reliable ammonia absorption heat pump can be provided by using a rust preventive which is easy to handle and does not pollute the environment.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The absorption heat pump of the present invention
To achieve the above object, a primary circuit is formed by welding an iron-based material, and as a rust preventive, nitrite, nitrate, borate, metal hydroxide, molybdate, phosphate, It is used in combination of at least two or more of phosphotungstate, silicate and silica gel. By combining the rust preventive agent, defects (pitting corrosion, local corrosion) when used alone can be eliminated, and a more excellent rust preventive effect can be exhibited by a synergistic effect.

A primary circuit is formed by joining an iron-based material by welding and nickel brazing, and a rust preventive effective for the iron-based material and a rust preventive effective for the nickel braze are formed. , And at least two types are used in combination. By combining effective rust preventive agents with each other, an excellent rust preventive effect can be exerted on both materials.

As an effective rust inhibitor for iron-based materials, nitrites, nitrates, borates, metal hydroxides, and molybdates are used.

Further, as an effective rust preventive for the nickel brazing material, sulfate, phosphate, tungstate, silicate tungstate, silicate and silica gel are used.

Further, nitrite and phosphate are added as a rust preventive. The synergistic effect of the rust-preventing effect of nitrite on iron-based materials and the rust-preventing effect of phosphate on nickel brazing material can be exhibited.

Further, nitrite and water glass are added. Excellent rust prevention effect can be exhibited by the anode type rust prevention effect of nitrite and the adsorption type rust prevention effect of water glass.

Further, water glass and a phosphate are added as rust preventives. In both cases, the rust-preventive effect can be exhibited by the adsorption-type rust-preventive action and the anode-type rust-preventive action which has some.

Further, nitrite and silica gel are added as a rust preventive. Excellent rust preventive effect can be exhibited by the anode type rust preventive action of nitrite and the adsorption type rust preventive action of silica gel.

At the outlet of the absorber, a suction tank having a filter below the inside and a gas reservoir above the inside is provided, and a valve is provided above the suction tank. Thereby, the working medium can be filled from the valve, and the deterioration generated gas can be discharged.

Further, a temperature detector is provided at least on the side wall of the gas reservoir of the suction tank. This makes it possible to detect the generation of the degradation product gas.

Further, a rust preventive storage bag is provided in the suction tank of the solution pump for storing the rust preventive and having an elution hole for eluting the rust preventive. This allows
It is possible to cope with the case where the solubility of the rust inhibitor is low or the case where the rust inhibitor is consumed, and it is possible to elute a necessary amount of the rust inhibitor during the actual operation and exhibit the rust prevention effect.

Further, among the element parts constituting the primary circuit,
At least the working medium contact surfaces in the regenerator, rectifier, and solution heat exchanger are surface-treated in advance, and a rust inhibitor is added. By performing a surface treatment in advance, a dense and strong rust-proof coating can be formed.

Specifically, the surface treatment is performed by high-temperature oxidation. Thereby, an oxide film can be formed.

Further, specifically, a surface treatment is performed with a dichromate and an acid. Thereby, a chromium oxide film can be formed.

Further, specifically, a surface treatment is performed with silicate or silica gel and aqueous ammonia. Thereby, a film of silicon dioxide can be formed.

At least the regenerator, the rectifier, and the solution heat exchanger among the element parts constituting the primary circuit are made of stainless steel containing 0 to 2.5% of nickel and a rust preventive. Is added. Thereby, corrosion resistance can be improved.

Further, among the component parts constituting the primary circuit, a solution heat exchanger, a subcooler, an evaporator, a condenser, and an absorber are constituted as a laminated heat exchanger, and a plate material of the laminated heat exchanger is provided. A stainless steel containing nickel of 0 to 2.5% and a nickel brazing material containing 11 to 20% of chromium are used as a brazing material for brazing the plate material. By using a laminated heat exchanger, the size of the component parts can be reduced, and the corrosion resistance can be improved.

[0025]

EXAMPLE In order to carry out material evaluation under conditions close to actual operation, a loop-type material evaluation test apparatus 1 shown in FIG. 1 was manufactured. The loop-type material evaluation test apparatus 1 includes a tank 2, a heater 3 and a cooler 4, and a sample 5 is held at a position where it is immersed in a liquid in the tank. The ammonia water containing the rust inhibitor heated by the heater 3 generates steam. The generated steam is cooled by the cooler 4 through the tank 2 and returned to the heater 3 again. The pressure is the secondary cooling water 6 of the cooler 4.
Is set at a temperature of The energization of the heater 3 is controlled so that the temperature of the liquid in the tank 2 holding the sample 5 becomes constant. And sample 5 is an iron-based material steel type,
The setting is made so that differences in nickel brazing material, surface treatment, welding state, brazing state, and the like can be seen. The sample size is 10 × 40 mm, the plate thickness is 0.5 mm for iron-based materials, and 30 microns for nickel brazing materials. The test conditions were as follows: an aqueous ammonia concentration of 25 wt%, a temperature of 160 ° C., and a pressure of 20 kg / c.
m ² -G, and the evaluation time was 200 hours. The concentration of each rust inhibitor added was set to 0.01 to 2 wt% based on the amount of ammonia water, and charged into a loop-type material evaluation test apparatus. The evaluation was performed on the state of sample 5 (appearance, weight change, surface state),
The test was performed based on the liquid state and the surface states of the heater 3 and the tank 2. Hereinafter, examples of the absorption heat pump of the present invention will be described.

Example 1 As a sample 5, iron, iron alloy and stainless steel, which are iron-based materials, were subjected to a test. Further, nitrites, nitrates, borates, metal hydroxides, molybdates, phosphates, phosphotungstates, silicates, and silica gels were used as the rust preventive. The test was performed using sodium, potassium, magnesium, calcium, and ammonium as the ionic species for forming the salt of the rust inhibitor.

As a result, rust preventives (nitrite, nitrate, molybdate, phosphate) having a solubility of 1% or more in aqueous ammonia can be used even when used alone or in a non-added state. It exhibits a rust-preventing effect on the system material, and can be in a passive region when viewed from the potential viewpoint. The weight change rate is within ± 0.05%. Further, the appearance of the sample has metallic luster regardless of the presence or absence of coloring. From this, it can be said that the film thickness of the rust preventive film formed on the sample surface is extremely thin. However, even if the sample obtained good results in this way, micro surface observation (SEM, XM
A) Then, pitting corrosion and local corrosion were partially observed.

On the other hand, rust inhibitors having a low solubility of 0.5% or less in aqueous ammonia (borate, metal hydroxide,
In the case of phosphotungstate, silicate, silica gel) alone, it was found that the rust-preventing effect was insufficient. In this case, the surface of the sample turned black and the metallic luster disappeared.

Therefore, a test was conducted by combining a rust preventive with low solubility and a rust preventive with high solubility. For example, nitrite and borate, nitrite and silicate, and the like. In this case, the amount of the rust inhibitor added as a whole can be reduced by combining them. When the rust inhibitor is used alone, there is a risk of pitting corrosion and local corrosion, but such risk can be suppressed by combining the rust preventives.

(Embodiment 2) Actual system (primary circuit)
In order to make the heat exchanger more compact, for example, attempts have been made to manufacture heat exchangers such as absorbers, evaporators, condensers, etc. by using an iron-based material and brazing it using a nickel brazing material. is there. As a sample 5, a nickel brazing material was subjected to the test together with the iron-based material.

The rust preventive described in Example 1 is basically an anode-type rust preventive, which exhibits a rust preventive effect on iron-based materials. It has been found that corrosion is significantly accelerated for system materials.
Examples include nitrite, nitrate, borate, metal hydroxide, molybdate, phosphotungstate. In terms of potential, these rust preventives had a nickel brazing material as an active melting zone. In terms of the weight change rate, the weight is reduced by 10% or more. The conventionally used dichromate is a very effective rust inhibitor for both iron-based materials and nickel brazing materials. Weight change rate of nickel brazing material is -0.5
%Met.

On the other hand, it has been found that the rust-proofing effect is small for iron-based materials, but has a rust-proofing effect for nickel brazing materials. For example, sulfate, phosphate, tungstate, silicate tungstate, and the like. These have a rust-preventing effect equal to or higher than that of dichromate when limited to nickel brazing material alone. The weight change rate was within -0.5%.

Therefore, when a test was conducted by combining a rust inhibitor effective for iron-based materials and a rust inhibitor effective for nickel brazing material, it was possible to obtain an effective rust inhibitor for both materials. .

Furthermore, it is rather effective on iron-based materials by itself, and not so effective on nickel-based materials, but by combining this with a rust inhibitor effective only on iron-based materials, Some of them also show a rust prevention effect. For example, silicate, silica gel, etc.

The ionic species forming the salt include sodium, potassium, magnesium, calcium, nickel, ammonium and the like. Here, it is considered that the nickel salt is effective because the ion balance as nickel ions is involved in corrosion.

Example 3 A particularly effective first rust inhibitor combination is 1% sodium nitrite as nitrite and 2% sodium phosphate as phosphate. This can be considered to be a synergistic effect of the antirust effect of sodium nitrite on the iron-based material and the anticorrosion effect of sodium phosphate on the nickel brazing material.

The combination of the second rust inhibitor is 1 to 2% of sodium nitrite as a nitrite and 1 to 2% of water glass as a silicate. This can be interpreted as a synergistic effect of the anode type rust preventive action of sodium nitrite and the adsorption type rust preventive action of water glass. In addition, as a silicate, there are sodium silicate and potassium silicate. Specifically, there are crystalline ones such as ortho, sesqui, and meta, and a solution generally called water glass, all of which have an effect.

The combination of the third rust preventive is 0.05 to 0.5% of water glass and 0.01 to 0.5% of sodium phosphate as a phosphate. Both can be considered to be a synergistic effect of the adsorption-type rust preventive action and the anode-type rust preventive action having some.

The combination of the fourth rust inhibitor is sodium nitrite (1-2%) and silica gel (0.1-2.0%) as nitrite.
It is a combination of 2%. It can be interpreted that the excellent rust prevention effect can be exhibited by the anode type rust prevention effect of sodium nitrite and the adsorption type rust prevention effect of silica gel.

The rust preventives of these combinations are all
The weight change rate was within ± 0.05% for the iron-based material and within -0.5% for the nickel brazing material.

(Embodiment 4) FIG. 2 shows a configuration diagram of Embodiment 4. At the outlet of the absorber 7, a filter 8 at the lower part inside
A suction tank 10 having a gas reservoir 9 above the inside
Is provided. A valve 11 is provided above the suction tank 10. The suction tank 10
A liquid guide plate 12 for introducing the liquid that has exited the absorber 7 into the filter 8 is provided on the filter 8 inside. Reference numeral 13 denotes a solution pump.

With this configuration, the valve 11 can be filled with ammonia water (working medium) containing a rust inhibitor,
The filter 8 is always connected to the solution pump 13 even during operation.
Since the working medium can be supplied through the filter, contamination of the solution pump 13 can be prevented. In addition, non-condensable gas (hydrogen) generated due to material deterioration during operation can be stored in the gas reservoir 9, and can be discharged to the outside via the valve 11 when generated in excess of the capacity of the gas reservoir 9. Therefore, it is possible to prevent a reduction in performance due to generation of non-condensable gas. In addition, since ammonia gas is also contained in the non-condensable gas from the valve 11, it is preferable to absorb this in an absorbing solution provided outside, for example, water, an acidic aqueous solution, or the like. Omitted.

(Embodiment 5) FIG. 3 shows a configuration diagram of Embodiment 5. The difference from FIG. 2 is that an A temperature detector 14 and a B temperature detector 15 are provided on the side wall of the inflow portion from the absorber 7 of the suction tank 10 and on the lower side wall.

As a result of the actual evaluation, it was found that when non-condensable gas was generated, the temperature of the side wall of the gas reservoir 9 was lowered. Then, when the temperature detected by the A temperature detector 14 decreases and the temperature difference between this temperature and the temperature detected by the B temperature detector 15 expands beyond a certain set value, it is assumed that non-condensable gas is generated. Can be detected. Although omitted in FIG. 3, the valve 11 is electrically operated and an arithmetic and control unit is provided, and the valve 11 is opened and closed by the signals of the A temperature detector 14 and the B temperature detector 15 so that the valve 11 is automatically disabled. It is also possible to discharge condensable gas.

(Embodiment 6) FIG. 4 shows a configuration diagram of Embodiment 6. The difference from FIG. 2 is that a rust preventive storage bag 16 that stores a rust preventive and has a rust preventive elution hole is provided. The position of the rust preventive storage bag 16 is disposed in the filter 8 in FIG. 4, but it goes without saying that it may be anywhere in the liquid.

The combination of effective rust inhibitors described in the above-mentioned Example 3 is not completely soluble in aqueous ammonia. In the case of natural circulation without using a solution pump in the primary circuit, or even in a cycle using a solution pump, if the solution pump is resistant to contamination such as a diaphragm type, a combination of such rust preventives is used. Can sufficiently be put to practical use. However, if it is vulnerable to contamination such as a gear type solution pump, it cannot be put to practical use with the combination of the rust preventive as it is.

However, on the other hand, although it is not completely dissolved, the fact that the eluted component exhibits a rust-preventive effect is the same as the rust-preventive agent on the inner surface of the primary circuit when this rust-preventive agent is used It is clear from the fact that the element is attached.
From this, it has been found that it is not necessary to completely dissolve the rust inhibitor.

Therefore, in the case of such a rust preventive, the rust preventive is stored in the suction tank 10 of the solution pump 13 and has an elution hole for eluting the rust preventive. A rust-preventive agent storage bag 16 composed of a fluororesin filtration filter having the following was provided for the test. As a result, it was possible to prevent deterioration of the solution pump due to contamination while maintaining the rust prevention effect.
Thereby, it is possible to cope with the case where the solubility of the rust inhibitor is low or the rust inhibitor is consumed, and it is possible to elute a necessary amount of the rust inhibitor during the actual operation and exhibit the rust preventing effect.

(Embodiment 7) Of the component parts constituting the primary circuit, at least the working medium contact surfaces in the regenerator, rectifier, and solution heat exchanger exposed to high temperatures are subjected to surface treatment in advance and are prevented. Rust was added.

The rust-preventive film formed on the inner wall of the primary circuit made of stainless steel by the rust-preventive agent has a process of once destroying the passivation film existing at the beginning and a process of contacting the inner wall with the rust-preventive agent. It is supposed that the antioxidant is formed by an oxidation process using a rust inhibitor there. As a result of analyzing the rust-preventive film formed by the rust-preventive agent in actual operation, voids are present and the adhesion to the base material is weak, and the film is not a dense film. It is considered that the cause is that the working medium is flowing and the flowing state is uneven. Further, in the actual machine, there are places such as gas spaces where the rust preventive agent cannot be reached. The purpose of the surface treatment in advance is to form a dense and strong rust-preventive film and to assure rust-prevention at places where the rust-preventive agent cannot be reached.

As a first embodiment of the surface treatment, the surface treatment was carried out by high-temperature oxidation and heating in air at 500 ° C. for one hour. As a result, an oxide film could be formed.

As a second embodiment, a surface treatment was carried out at 160 ° C. using an aqueous solution of potassium dichromate as a dichromate and an aqueous solution of sodium nitrate as an acid. As a result, a chromium oxide film could be formed.

As a third embodiment, a surface treatment was performed at 160 ° C. for 2 hours using sodium metasilicate as a silicate, or silica gel and aqueous ammonia. This allows
A silicon dioxide film could be formed.

In each case, it was confirmed that the formed rust-preventive film was dense, had high adhesion to the base material, and had corrosion resistance. Further, by adding a rust inhibitor after performing such a surface treatment, the durability of the actual machine could be significantly improved.

(Embodiment 8) Of the component parts constituting the primary circuit, at least a regenerator, a rectifier,
The solution heat exchanger was made of stainless steel having a nickel content of 2.5% or less, and a rust preventive was added to evaluate the actual heat exchanger. The stainless steel having a nickel content of 2.5% or less is, for example, SUS430 and SUS434 for ferrite and SUS431 and SUS440 for martensite.

From the material evaluation results, it was found that the deterioration of the austenitic stainless steel containing nickel was caused by nickel as a starting point of corrosion. Further, they have found that the corrosion resistance can be improved by using a ferrite or martensitic stainless steel containing no nickel. Therefore, as a result of carrying out an actual machine evaluation using these materials,
It was confirmed that the durability could be greatly improved. The chromium content of stainless steel is preferably 16% or more.

(Embodiment 9) Among the component parts constituting the primary circuit, the solution heat exchanger, the subcooler, the evaporator, the condenser, and the absorber are constituted as a laminated heat exchanger, and the laminated heat exchanger is used. Stainless steel having a nickel content of 0 to 2.5% in the plate material, and 11 to 20% in the brazing material for brazing the stainless plate material.
Was used.

The chromium content is related to the corrosion resistance of the material to ammonia water containing a rust inhibitor. Looking at the nickel brazing material, 6-8% of BNi-2 and 11 of BNi-7
-15%, BNi-1 13-15%, BNi-5 1
It was 8 to 20%, and it was found that in this order, the corrosion resistance to ammonia water was improved. By making the component parts a laminated heat exchanger, the size can be reduced and the corrosion resistance can be improved.

[0059]

As described above, according to the present invention,
The following effects are obtained.

(1) Since at least two kinds of rust inhibitors effective for iron-based materials are used in combination, pitting corrosion and local corrosion can be suppressed.

(2) By combining at least two of the rust preventives effective for iron-based materials and the rust preventives effective for nickel brazing material, it is possible to provide an effective rust preventive for both materials. .

(3) By combining nitrite and phosphate, an excellent rust preventive can be provided.

(4) By combining nitrite and water glass, an excellent rust inhibitor can be provided.

(5) An excellent rust inhibitor can be provided by combining water glass and a phosphate.

(6) An excellent rust inhibitor can be provided by combining nitrite and silica gel.

(7) Since the suction tank is provided with the gas reservoir and the valve, the degradation gas can be discharged.

(8) Since the temperature detector is provided in the gas reservoir of the suction tank, the deterioration generated gas can be detected.

(9) Since the storage tank is provided with a rust preventive agent storage bag in the suction tank, contamination of the solution pump can be prevented.

(10) Since the working medium contact surface is preliminarily surface-treated, the corrosion resistance can be improved.

(11) Since the surface treatment is performed by high-temperature oxidation, an oxide film can be formed on the inner wall of the primary circuit.

(12) Since the surface treatment is performed with a dichromate and an acid, a chromium oxide film can be formed on the inner wall of the primary circuit.

(13) Since the surface treatment is performed with silicate or silica gel and aqueous ammonia, a coating of silicon dioxide can be formed on the inner wall of the primary circuit.

(14) The component parts are made of nickel of 0 to 2.5
%, The corrosion resistance of the parts can be improved.

(15) Using the component parts as a laminated heat exchanger
Stainless steel containing 0 to 2.5% nickel and 11 to 2
Since it is made of nickel brazing material containing 0% chromium,
Corrosion resistance can be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the configuration of a material evaluation test apparatus for an ammonia absorption heat pump according to the present invention.

FIG. 2 is a sectional view showing the configuration of a fourth embodiment of the ammonia absorption heat pump of the present invention.

FIG. 3 is a sectional view showing the configuration of a fifth embodiment of the ammonia absorption heat pump of the present invention.

FIG. 4 is a sectional view showing the configuration of a sixth embodiment of the ammonia absorption heat pump of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Material evaluation test device 8 Filter 9 Gas reservoir 10 Suction tank 14, 15 Temperature detector 16 Rust prevention agent storage bag

Claims (17)

[Claims] A primary circuit is formed by welding an iron-based material, and nitrite, nitrate,
An ammonia absorption heat pump used in combination of at least two of borate, metal hydroxide, molybdate, phosphate, phosphotungstate, silicate, and silica gel. 2. A primary circuit is formed by joining an iron-based material by welding and nickel brazing, and a rust preventive effective for the iron-based material and a rust preventive effective for the nickel braze are included. , An ammonia absorption heat pump used in combination of at least two or more types. 3. The ammonia absorption heat pump according to claim 2, wherein a nitrite, a nitrate, a borate, a metal hydroxide, or a molybdate is used as a rust inhibitor effective for iron-based materials. 4. The ammonia absorption heat pump according to claim 2, wherein a sulfate, phosphate, tungstate, silicate tungstate, silicate, or silica gel is used as a rust preventive effective for the nickel brazing material. 5. An ammonia absorption heat pump obtained by adding a nitrite and a phosphate as a rust preventive. 6. An ammonia absorption heat pump obtained by adding nitrite and water glass as a rust preventive. 7. An ammonia absorption heat pump obtained by adding water glass and a phosphate as a rust preventive. 8. An ammonia absorption heat pump obtained by adding nitrite and silica gel as a rust preventive. 9. An ammonia absorption heat pump having a suction tank provided with a filter below the inside and a gas reservoir above the inside at the outlet of the absorber, and a valve attached to the upper part of the suction tank. 10. The ammonia absorption heat pump according to claim 9, wherein a temperature detector is provided at least on a side wall of the gas reservoir of the suction tank. 11. An ammonia absorption type heat pump comprising a rust preventive agent stored in a suction tank of a solution pump and containing a rust preventive agent having an elution hole for eluting the rust preventive agent. 12. Among the element parts constituting the primary circuit, at least a surface of a working medium contact surface in a regenerator, a rectifier, and a solution heat exchanger is subjected to a surface treatment and a rust inhibitor is added. Ammonia absorption heat pump. 13. A surface treatment by high-temperature oxidation.
2. The ammonia absorption heat pump according to 2. 14. The ammonia absorption heat pump according to claim 12, wherein the surface treatment is performed with a dichromate and an acid. 15. The ammonia absorption heat pump according to claim 12, wherein the surface treatment is performed with silicate or silica gel and aqueous ammonia. 16. At least a regenerator, a rectifier, and a solution heat exchanger among the component parts constituting the primary circuit are made of stainless steel containing 0 to 2.5% of nickel and a rust preventive. Ammonia absorption heat pump made by adding 17. A component heat exchanger, a subcooler, an evaporator, a condenser, and an absorber among the component parts constituting the primary circuit are constituted as a laminated heat exchanger, and a plate material of the laminated heat exchanger is provided. An ammonia absorption heat pump using stainless steel containing 0 to 2.5% nickel and nickel brazing containing 11 to 20% chromium as a brazing material for brazing the plate material.