JPH07269994A - Cooling system - Google Patents

Abstract

PURPOSE:To prevent substitute fluorocarbon, reduction in cooling function or corrosion of metal of a device by a method wherein oxygen absorbing agent is arranged in a circulating system of a cooling system. CONSTITUTION:In a refrigerator having a freezing device operated under a cycle of compression and liquefaction of refrigerant and expansion gasification, an oxygen absorbing agent storing part 5 is arranged at a pocket part where it is out of a refrigerant compressor 1 so as to arranged the oxygen absorbing agent. The oxygen absorbing agent to be applied is composed of oxygen, moisture, carbonic acid gas and absorbing composition of organic material. More practically, the agent is composed of composition including organic material having non-saturated coupling, and composition including alkali metal or oxide of alkaline earth metal can be added. With such an arrangement as above, decomposition of the substitute fluorocarbon of the refrigerant is prevented. Even if a small amount of decomposition of the substitute fluorocarbon is present, the decomposed product is absorbed into the oxygen absorbing agent 5 and the substitute fluorocarbon can be used as refrigerant without making any corrosion of metallic material of the freezing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system using chlorofluorocarbon as a refrigerant, and more specifically, it is used in refrigerators for home use, refrigerators, room coolers, car coolers and the like, as well as industrial refrigerators and freezers. In addition, the present invention relates to a cooling system which can be stably operated for a long period of time without decomposing even if alternative CFCs are used as a refrigerant.

[0002]

2. Description of the Related Art Household and industrial refrigeration and refrigeration equipment is
A cooling system using a compression liquefaction-expansion gasification cycle of a refrigerant has been adopted. In the cooling system, a specific CFC has been conventionally suitably used as a stable refrigerant.

However, specific CFCs are completely abolished in 1995 as ozone depleting substances. For this reason, alternative CFCs such as designated CFCs or alternative CFCs are being used in place of CFCs, but CFCs are more likely to decompose than CFCs. It also causes corrosion of the metal material of the cooling device and a decrease in the degree of vacuum, resulting in a decrease in thermal efficiency.

Fluorocarbons are inherently hygroscopic, and it is not preferable that water is mixed with the refrigerant into the cooling system. Conventionally, activated carbon or a water absorbent is arranged in the cooling system to remove water. Is being done. However, in the case of alternative CFCs, simply removing water in the cooling system is not sufficient, and the alternative CFCs are easily decomposed by trace oxygen introduced into the system or leaking, Furthermore, the use of alternative CFCs has a problem in the cooling function and durability of refrigerating / refrigerating equipment because it accelerates the decomposition of the lubricating oil of the compressor.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to prevent decomposition of alternative CFCs in a cooling system system, thereby preventing deterioration of cooling function and corrosion of apparatus metal, and refrigeration using alternative CFCs. -To solve the above problems of refrigeration equipment.

[0006]

Means for Solving the Problems The inventors of the present invention have made various investigations in view of the above-mentioned problems. As a result, an oxygen absorbent is arranged in a refrigerant circulation system of a cooling system using alternative CFCs as a refrigerant, and Furthermore, they have found that the above problems can be easily solved by trapping water, carbon dioxide gas and organic matter, and have completed the present invention.

That is, the present invention is an invention relating to a cooling system characterized by arranging an oxygen absorbent in a refrigerant circulation system of a cooling system using Freon as a refrigerant by a cycle of compression liquefaction and expansion gasification of the refrigerant. Furthermore, the present invention relates to a cooling system in which the oxygen absorbent arranged in the circulation system of the refrigerant comprises a composition that absorbs oxygen, moisture, carbon dioxide gas and organic matter. More specifically, the invention relates to a cooling system including a composition in which an oxygen absorbent arranged in a circulation system of a refrigerant contains an organic compound having an unsaturated bond.

In the cooling system according to the present invention, first, the CFC of the refrigerant is compressed by the compressor, the compressed refrigerant radiates heat by the radiator and is condensed and liquefied, and then the liquefied refrigerant is adiabatically expanded and vaporized by the expander. As a result, the cooled refrigerant exchanges heat with the cooler to take heat from the outside and cool. The refrigerant gas that has completed the heat exchange is returned to the compressor again, and the cooling cycle of compression liquefaction-expansion gasification is repeated.

In the present invention, the oxygen absorbent is arranged in the refrigerant circulation system of the above cooling system, but the arrangement position is not particularly limited as long as the oxygen absorbent can exhibit the absorbing function, and the refrigerant CFC is A location that can contact the oxygen absorbent in a gaseous state is preferable. For example, a location where a gaseous refrigerant is compressed by a compressor, or a location where the refrigerant radiates heat in a radiator to condense, a location where a liquid refrigerant is vaporized under vacuum, and in any case the refrigerant is It is preferable that the oxygen can be efficiently contacted with the oxygen absorbent in a gaseous state.

As the CFC of the refrigerant in the present invention, alternative CFCs such as designated CFCs and CFC alternatives can be used. Typical examples of designated CFCs are HCFC-22 and H
CFC-123, HCFC-124, HCFC-141
B, HCFC-142B, HCFC-225CA, HC
FC-225CD and the like, and typical examples of CFC alternatives include HFC-125, HFC-134A, and HFC-.
152A etc. are mentioned.

The oxygen absorbent according to the present invention is capable of absorbing oxygen in the substantial absence of water, and more preferably capable of absorbing water, carbon dioxide gas and organic substances. The oxygen absorbent used in the present invention is composed of a composition that absorbs oxygen, moisture, carbon dioxide gas and organic matter. Specifically, it is composed of the composition (A) containing an organic material having an unsaturated bond, and the composition (B) containing an oxide of an alkali metal or an alkaline earth metal can be further added.

The composition (A) containing an organic compound having an unsaturated bond is composed of an oxidation promoting substance, a basic substance and an adsorbent in addition to the organic compound having an unsaturated bond as the main ingredient. As the organic compound having an unsaturated bond, an unsaturated fatty acid compound and / or a chain hydrocarbon polymer having an unsaturated group is used.

The unsaturated fatty acid compound used herein includes an unsaturated fatty acid having 10 or more carbon atoms and at least one double bond between carbon atoms, an ester of the unsaturated fatty acid, and an unsaturated fatty acid ester. Oils and fats, salts of the unsaturated fatty acids, and the like. Examples of the unsaturated fatty acid having 10 or more carbon atoms and one or more double bonds between carbon atoms include, for example, oleic acid, linoleic acid, linolenic acid, arachidonic acid, parinaric acid, dimer acid, ricinoleic acid or ricinoleic acid. Examples of the unsaturated fatty acid compound include unsaturated fatty acids, esters of unsaturated fatty acids, fats and oils containing unsaturated fatty acid esters, metal salts of unsaturated fatty acids, and the like.

The chain hydrocarbon polymer having an unsaturated group is a chain hydrocarbon polymer having 10 or more carbon atoms and one or more double bonds between carbon atoms, and derivatives thereof.
The derivative may be, for example, a compound having a substituent such as a hydroxyl group or a formyl group. Examples of the chain hydrocarbon polymer having 10 or more carbon atoms and one or more double bonds between carbon atoms include chain unsaturated hydrocarbon polymers exemplified by butadiene, isoprene, and 1,3-pentadiene. Can be used, and the polymer may be an oligomer.

The organic compound having an unsaturated bond serves as a main agent for the oxygen absorption reaction, and preferably, the main agent is a transition metal salt of an unsaturated fatty acid or a mixture of a transition metal salt of an unsaturated fatty acid and an unsaturated fatty acid, or these. A mixture obtained by adding a hydrocarbon polymer having an unsaturated group to the mixture is used.
The unsaturated fatty acid compound and the chain hydrocarbon polymer may be mixed with impurities.

The oxidation-promoting substance is a substance which plays a role in the oxygen absorption reaction by the main agent. As an oxidation promoter,
Compounds of transition metals such as iron, cobalt, chromium, copper and nickel are used, and inorganic acid salts such as carbonates, sulfates and nitrates of the above transition metals, saturated fatty acid salts, organic acid salts such as unsaturated fatty acid salts, An amine complex or the like is used. It is desirable that the oxidation promoting substance is uniformly mixed with the main agent, and it is preferable to add it as a transition metal salt of unsaturated fatty acid of the main agent.

The basic substance referred to here is a substance capable of absorbing an acidic substance as a basic substance, and plays a role of supplementing not only the acidic substance generated by the oxygen absorption of the main ingredient but also the acidic substance. I wish I had it. The basic substance is not particularly limited as long as it achieves the purpose, but preferably includes alkali metal or alkaline earth metal oxides, hydroxides, carbonates, organic acid salts and organic amines.

The adsorbing substance is a substance that supports the main agent, increases the contact area with oxygen, plays the role of a carrier for increasing the oxygen absorption rate, and is capable of absorbing water, and further can be an acidic substance. Is preferred. Silica gel, activated carbon, zeolite, activated clay and the like are used as preferable specific examples of the adsorbent.

The proportion of each component of the composition (A) is not particularly limited, but 0.01 to 10 parts by weight of the oxidation promoting substance and 1 part of the basic substance with respect to 100 parts by weight of the main component of the unsaturated organic compound. ˜1000 parts by weight, and the adsorbing material preferably comprises 10 to 1000 parts by weight.

As the composition (A), it is preferable that the above-mentioned respective components are mixed and the liquid substance is supported on the adsorbent substance. The mixture of the composition (A) can be in the form of granules, tablets, sheets, etc., and its shape is not particularly limited.

The composition (A) is usually packaged in a breathable packaging material and used as an oxygen absorbent. Also, a granular or tablet composition (A) packed in layers
Can be placed in the cooling system to allow the refrigerant CFCs to pass through. As the breathable packaging material of the package, for example, breathable materials such as paper, non-woven fabric, and microporous membrane, or a laminate in which a base material such as a perforated plastic film is laminated is used.

The composition (B) containing an oxide of an alkali metal or an alkaline earth metal is a composition for absorbing water, carbon dioxide gas and organic matter. Specifically, as the substance that absorbs water and carbon dioxide, a substance obtained by impregnating an alkaline earth oxide with a solid alkali metal oxide or an alkali metal hydroxide is used. Further, an adsorbent is used as a substance that absorbs organic substances, and specific examples thereof include silica gel, activated carbon, zeolite, activated clay and the like, which are preferably used after vacuum treatment or heat treatment at 100 ° C. or higher. The composition (B) can be used as a mixture with the composition (A), but only the composition (B) can be arranged as a separate package together with the package of the composition (A).

In the cooling system of the present invention, it is desirable that the liquefied refrigerant is vaporized at a vacuum degree of 600 mmHg or less, preferably 500 mmHg or less and a temperature of 0 ° C. or less. The oxygen partial pressure in the cooling system of the present invention is 1 mmHg or less, and the water partial pressure is 1 mmHg.
Maintained below.

[0024]

EXAMPLES The present invention will be described based on examples. The present invention is not bound by this embodiment. Example 1 to Example 10 In Examples, in a refrigerator equipped with a refrigerating apparatus by the compression liquefaction-expansion gasification cycle of the refrigerant shown in FIG. 1, oxygen is absorbed in a pocket portion as shown in FIG. An agent storage was provided and an oxygen absorber was placed.

As the oxygen absorbent, the following composition (A) and composition (B) were filled in an air-permeable paper bag (70 × 70 mm) lined with an open polyethylene film to form an oxygen absorbent package. Using. Composition (A): 0.2 g of cobalt naphthenate was dissolved in 1 g of soybean oil fatty acid to impregnate 5 g of silica, and then 0.1 g of slaked lime was coated to form granules. The granular composition and granular calcium oxide Composition (A) was prepared by mixing 2.5 g. Composition (B): 1 at 200 ° C. in an atmosphere of 10 mmHg
Composition (B) was prepared by mixing 10 g of activated carbon from which carbon dioxide was removed by heat treatment for a period of time and 5 g of quick lime with soda lime impregnated with 1 g of an aqueous sodium hydroxide solution (50%).

In each of Examples 1 to 10, the type of the refrigerant was changed, and the refrigerator in which the oxygen absorbent was placed was continuously moved. Refrigerator has about 1.2kg of refrigerant
A carbon steel pipe for pressure piping was used for the piping of the main part of the device. Table 1 shows the discolored state of the inner wall of the pipe as the oxygen partial pressure and the water partial pressure of the cooling system after being operated for one year, the amount of water in the refrigerant, and the corrosion index of the refrigeration system. As a comparative example, a synthetic zeolite (200
The results when 21 g (dried at ℃) are used are also shown in Table 1. Table 2 shows the ozone depletion potential of the used refrigerant and the water content before use.

As shown in the examples of Table 1, by using the oxygen absorbent according to the present invention, the partial pressure of oxygen and water in the system is lowered, which prevents the decomposition of the refrigerant and causes the precursor of corrosion. No discoloration of the pipe was observed. On the other hand, in the comparative example using the synthetic zeolite instead of the oxygen absorbent, not only was the water partial pressure not sufficiently lowered, but because oxygen was not removed, the decomposition of the refrigerant was observed, and significant discoloration of the piping It was recognized and corrosion had started.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

EFFECTS OF THE INVENTION According to the present invention, oxygen and water introduced or leaked into the system are trapped by the oxygen absorbent arranged in the refrigerant circulation system to prevent decomposition of CFC substitutes for the refrigerant. To be done. Even if there is a slight amount of decomposition of the CFC substitutes, the decomposition products are absorbed by the oxygen absorbent, and the CFC substitutes are easily converted into a refrigerant without reducing the refrigeration capacity or corroding the metal material of the refrigeration system. Can be used.

[Brief description of drawings]

FIG. 1 Cooling system by compression liquefaction-expansion gasification cycle of refrigerant

[Fig.2] Location of oxygen absorber

[Explanation of symbols]

 1 Compressor 2 Radiator 3 Expansion valve 4 Cooler 5 Placement of oxygen absorbent 51 Oxygen absorbent

Claims (3)

[Claims] 1. A cooling system, wherein an oxygen absorbent is arranged in a refrigerant circulation system of a cooling system which uses Freon as a refrigerant by a cycle of compression liquefaction and expansion gasification of the refrigerant. 2. The cooling system according to claim 1, wherein the oxygen absorbent is a composition that absorbs oxygen, moisture, carbon dioxide gas and organic matter. 3. The cooling system according to claim 1, wherein the oxygen absorbent is a composition containing an organic compound having an unsaturated bond.