JP2005331124A - Heat exchanger having air cleaning function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of oxidizing and decomposing odor components attached to a surface of the heat exchanger and cleaning the air including the odor components passing through the heat exchanger. <P>SOLUTION: A polyaniline-containing coating film 17 including polyaniline, is formed on a surface of a base material 16 constituting a fin of an evaporator, a moisture permeable layer 18 is stacked on the polyaniline coating film 17, and an adsorbent layer 20 supporting catalyst 21 is layered on the moisture permeable layer 18. Then the polyaniline-containing coating film 17 and the adsorbent layer 20 are electrically connected through a power source 23. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchanger having an air cleaning function, and is particularly suitable for application to a vehicle heat exchanger.

  Conventionally, as a technique for preventing odor components (organic substances) from adhering to a heat exchanger, a technique in which a film made of polyaniline is formed on the surface of a heat exchanger is known in Patent Document 1 (hereinafter referred to as a conventional example). Called).

In the conventional example of FIG. 5, a coating 17 made of polyaniline is formed on the surface of a base material 16 constituting a core portion of an evaporator that cools air for air conditioning into a well-known vehicle interior. The polyaniline film 17 activates dissolved oxygen dissolved in the condensed water 19 when the condensed water 19 generated on the surface of the evaporator comes into contact, and generates superoxide anion radicals (.O ₂ ⁻ ) that are active oxygen.

By this superoxide anion radical (.O ₂ ⁻ ), the odor component adhering to the evaporator surface can be oxidatively decomposed (cleaned). Therefore, it is possible to prevent the odor component that gradually increases and adheres to and accumulates on the surface of the evaporator with the passage of years of use from escaping from the surface of the evaporator and flowing into the vehicle interior. That is, it is possible to prevent the problem of unpleasant odor from the air outlet felt by the passengers in the vehicle interior.
JP 2002-71296 A

  However, in the evaporator of Patent Document 1, although the odor component adhering to the evaporator surface can be oxidatively decomposed, the odor component contained in the air passing through the core portion cannot be decomposed. There is a problem that the component flows.

  In view of the above points, an object of the present invention is to purify air containing an odor component that passes through the heat exchanger in a heat exchanger that can oxidatively decompose the odor component adhering to the surface of the heat exchanger.

In order to achieve the above object, according to the first aspect of the present invention, in the heat exchanger having an air cleaning function, heat exchange is performed between the fluid formed in the base material (16) and the air flowing through the inside (A). A polyaniline-containing film (17) containing polyaniline, which is disposed so as to cover the heat exchange part (15) and at least a part of the substrate (16) and generates active oxygen when it comes into contact with moisture, and a polyaniline-containing film (17 ) And a moisture permeable layer (18) through which moisture (B, 19) generated in the heat exchange section (15) permeates, and a moisture permeable layer (18) and odor in the air (A). An adsorbent layer (20) for adsorbing components, a catalyst (21) supported on the adsorbent layer (20), and a power source (20) electrically connected to the adsorbent layer (20) and the polyaniline-containing film (17) 23)
The polyaniline-containing coating (17) is characterized in that a reduction current is supplied.

  According to this, the odor component in air (A) adsorb | sucks to an adsorbent layer (20). On the other hand, the moisture (B, 19) generated in the heat exchange part (15) permeates the moisture permeable layer (18) and comes into contact with the polyaniline-containing coating (17), so that it dissolves in the moisture (B, 19). The dissolved oxygen is converted to continuously generate superoxide anion radical which is active oxygen.

  Furthermore, this superoxide anion radical is easily converted to hydrogen peroxide in water (B, 19). The moisture (B, 19) containing hydrogen peroxide permeates the moisture permeable layer (18) and penetrates the adsorbent layer (20), and the catalyst (21 supported on the surface of the adsorbent layer (20)). ). At this time, active oxygen and hydroxy radical having strong oxidizing power are generated, and the odor component adsorbed on the adsorbent layer (20) can be oxidatively decomposed by the hydroxy radical.

  Thus, the odor component in the air (A) passing through the heat exchange part (15) can be decomposed to clean the air (A). In the present invention, the odor component in the moisture (B, 19) can also be oxidatively decomposed by the superoxide anion radical generated when the moisture (B, 19) contacts the polyaniline-containing coating (17).

  Further, as in the invention described in claim 2, in the heat exchanger having an air cleaning function described in claim 1, if activated carbon fibers having conductivity are used as the adsorbent layer (20), the heat exchanger is concretely used. The odor component contained in the air (A) passing through the heat exchanger can be adsorbed to the air to be purified.

  Moreover, since activated carbon fiber has electroconductivity, an adsorbent layer (20) can be used as a counter electrode for supplying a reduction current with respect to a polyaniline containing film (17). As a result, hydrogen peroxide can be generated continuously in the polyaniline in the polyaniline-containing coating (17), which becomes a base of superoxide anion radical and hydroxy radical.

  Further, as in the invention described in claim 3, in the heat exchanger having the air cleaning function described in claim 1 or 2, the moisture permeable layer (18) is an insulating porous film, and the adsorbent layer is used. You may prevent a short circuit when (20) and a polyaniline containing film (17) are electrically connected via a power supply (23). In addition, since it is porous, the water | moisture content (B, 19) containing the hydrogen peroxide which generate | occur | produced on the polyaniline containing film | membrane (17) surface naturally can reach the adsorbent layer (20).

  Moreover, in the heat exchanger having the air cleaning function according to any one of claims 1 to 3, as in the invention according to claim 4, the catalyst (21) is made of iron, copper, zinc, or titanium. If at least one is included, hydrogen peroxide contained in the water soaked in the adsorbent layer (20) can be reduced, and active oxygen and hydroxy radicals having strong oxidizing power can be generated.

  Further, in the heat exchanger having the air cleaning function according to any one of claims 1 to 4 as in the invention described in claim 5, the base material (16) may be made of an aluminum alloy or a resin.

  Further, in the heat exchanger having an air cleaning function according to any one of claims 1 to 5, as in the invention according to claim 6, the polyaniline in the polyaniline-containing film (17) is represented by the chemical formula 5 to the chemical formula. At least one of the polyanilines represented by 8 may be included.

  Further, in the heat exchanger having the air cleaning function according to any one of claims 1 to 6, as in the invention according to claim 7, moisture generated in the heat exchange section (15) is the air (A ) Condensed water (B, 19) in which the water content is condensed.

  Further, in the heat exchanger having an air cleaning function according to any one of claims 1 to 7, as in the invention according to claim 8, the fluid flowing through the heat exchanger is used as a heat exchanger (15 It is good also as a refrigerant | coolant which evaporates by the heat absorption from the air (A) in.

  According to a ninth aspect of the present invention, in the heat exchanger having an air cleaning function according to any one of the first to eighth aspects, the power source is an in-vehicle battery (23) mounted on a vehicle, It is characterized by air conditioning air (A) flowing into the passenger compartment.

  According to this, as described in claim 1, the odor component in the air-conditioning air (A) flowing into the passenger compartment can be decomposed to clean the air (A), and further in the moisture (B, 19). Odor components can also be oxidatively decomposed. Therefore, it is possible to prevent the problem of unpleasant odor from the air outlet that is felt by passengers in the passenger compartment.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
In the present embodiment, a heat exchanger according to the present invention is applied to an evaporator of a vehicle air conditioner using a vapor compression refrigeration cycle, and FIG. 1 is a front view of the evaporator according to the present embodiment. .

  Note that the vapor compression refrigerator is a method in which a low-pressure refrigerant is evaporated by a low-pressure side heat exchanger such as an evaporator to absorb heat from a low-temperature side, and the evaporated gas-phase refrigerant is compressed to a high temperature. The heat absorbed by the low temperature side is dissipated to the high temperature side, and usually comprises a compressor, a radiator, a decompressor, an evaporator, and the like.

  As shown in FIG. 1, the evaporator 10 includes a plurality of tubes 11 through which refrigerant flows, header tanks 12 and 13 communicating with the plurality of tubes 11 at both longitudinal ends of the tubes 11, Fins 14 that increase the heat transfer area with the air-conditioning air (arrow A) that is joined to the outer surface and flows into the evaporator 10 are provided. Here, the heat exchanging part composed of the fins 14, the tubes 11, and the like is referred to as a core part 15.

  Note that a side plate (not shown) that reinforces the core portion 15 is disposed at the end of the normal core portion 15. In FIG. 1, 12 a is an inflow joint through which refrigerant flows into the inflow side tank 12, and 13 a is an outflow joint 13 b through which refrigerant flows out from the outflow side tank 13. In the present embodiment, the components such as the tube 11 and the header tanks 12 and 13 are made of an aluminum alloy, and these are brazed and integrally joined.

  Next, the fins 14 of the core portion 15 will be described with reference to FIG. 2. In this embodiment, the fins 14 are also formed of an aluminum alloy base material 16 like the tubes 11 and the like. A polyaniline-containing coating 17 containing polyaniline is formed on the surface of the substrate 16, and a porous film 18 that is an insulator is laminated on the polyaniline-containing coating 17.

  An activated carbon fiber layer 21 that is a conductive material including the catalyst 21 is formed on the outermost surface. Further, lead wires 22 are connected to the polyaniline coating 17 and the activated carbon fiber layer 20, and the connecting portions are covered with a water-resistant resin. The lead wire 22 electrically connects the polyaniline-containing film 17 and the activated carbon fiber layer 20 via the battery 23.

  Next, a method for producing a test module that evaluates the air cleaning effect (corresponding to a method for producing the fin 14 in the evaporator 10 of the present embodiment) will be described.

(A) First, polyaniline is synthesized. 50 ml of 1 mol hydrochloric acid aqueous solution containing 12 g of ammonium persulfate sufficiently cooled in an ice-cooled bath was gradually added to 300 ml of 1 mol hydrochloric acid aqueous solution containing about 2.8 g of aniline which had been cooled, and the cooling continued for 1 hour 30 minutes. Stir. The solution changed from colorless to greenish blue, and a hydrochloric acid-doped polyaniline in which the anion A was a chlorine ion in the above chemical formula 5 was formed.
The product produced by the above method was suction filtered and washed well with 1 molar aqueous hydrochloric acid and acetone. Next, this is suspended in 28% aqueous ammonia and stirred for 24 hours, whereby a dedope type polyaniline represented by the above chemical formula 6 is obtained.

  (B) Next, 4 g of the dedope type polyaniline powder obtained by the synthesis method (A) is not aggregated with respect to 100 ml of NMP (N-methyl-2-pyrrolidone) in which 1 g of camphorsulfonic acid is dissolved. While taking care, it was dissolved little by little to obtain a 4% doped polyaniline solution.

  (C) Next, the base material 16 is pretreated. The aluminum alloy material (3 cm × 5 cm) as the base material 16 is immersed in 200 ml of a 5% sodium hydroxide aqueous solution kept at 60 ° C. for 30 seconds, then immersed in 200 ml of a 30% nitric acid aqueous solution for 60 seconds, and then tap water Wash with water for 30 seconds. This treatment removes surface contaminants such as oil and the oxide film formed on the surface of the aluminum alloy material.

  (D) Next, a 4% polyaniline solution was applied to both surfaces of the aluminum alloy material (base material 16) pretreated in (C) so that the polyaniline carrying amount on one surface was 0.2 mg / cm 2, The dope type polyaniline film | membrane 17 was formed in the thermostat kept at 140 degreeC, and it heated for 20 minutes, and formed the aluminum alloy material (base material 16) surface.

Toraytec ^R carbon made by Toray, which is an adsorbent layer 20 carrying a catalyst 21 on the surface of this polyaniline film 17, bonded with a Sumitomo Electric fine polymer pore flon ^R membrane (3 cm × 5 cm) as a moisture permeable layer 18. Paper TGP-H-120 (3 cm × 5 cm) was bonded. Further, the two lead wires 22 were electrically connected to the polyaniline film 17 and Toray-made Torayca ^R carbon paper (adsorbent layer 20) with silicon bonds, and this was used as a module for the test.

(E) In addition, 10MMFeCl as carrier a catalyst 21 to Toray Torayca ^R carbon paper TGP-H-120 (adsorbent layer 20), manufactured by Toray Industries, Trading ^R carbon paper TGP-H-120 (the adsorbent layer 20) _It was immersed in ₃ aqueous solutions for 10 minutes, and it was left to stand in a thermostat kept at 80 ° C. in an N ₂ atmosphere for 30 minutes and dried by heating.

  A laminated structure as shown in FIG. 2 was formed on the surface of the substrate 16 by the methods (A) to (E) described above.

  Next, the operation of the present embodiment in the above configuration will be described. When the air-conditioning air (A) flows into the core portion 15, the odor component in the air (A) is adsorbed on the adsorbent layer 20 (in FIG. 2, Arrow C).

  Further, the refrigerant flowing in the tube 11 absorbs heat from the air (A) directly or via the fins 14 and evaporates to be in a gas phase state. The air A is cooled by the endothermic heat of the refrigerant, but when the air A falls below the dew point, moisture in the air A condenses and adheres to the fin 14 surface (arrow B in FIG. 2). A dotted line 19 indicates the condensed water accumulated on the surface of the fin 14.

  The polyaniline-containing coating is configured such that a reduction current flows from the vehicle battery 23 when a switch in the lead wire 22 is turned on (energized state). Note that the potential applied to the polyaniline-containing film 17 is set to be lower than the oxidation-reduction potential of the base material 16 (aluminum alloy material) on which the polyaniline-containing film 17 is formed.

When the condensed water 19 and the polyaniline film 17 come into contact with each other, a reduction current is supplied to the polyaniline, and the polyaniline gives electrons to the dissolved oxygen in the condensed water 19 and the superoxide anion radical (.O ₂ ⁻ ) that is active oxygen. Are generated continuously.

Further, as shown in 2 · O ₂ ⁻ + 2H ⁺ → H ₂ O ₂ + O2 (hereinafter referred to as Formula A), the superoxide anion radical (• O ₂ ⁻ ) reacts with hydrogen ions in the condensed water 19. Hydrogen peroxide water is generated.

This hydrogen peroxide solution is reduced by the action of the catalyst 21 (iron in this case) carried on the activated carbon fiber layer (adsorbent layer 20), and H ₂ O ₂ + Fe ²⁺ → OH + OH ⁻ + Fe ³⁺ (hereinafter referred to as Formula B) As shown in FIG. 2, active oxygen and hydroxy radical (.OH) having strong oxidizing power are continuously generated (arrow D in FIG. 2). Then, this oxy radical (.OH) oxidizes and decomposes the odor component adsorbed on the adsorbent layer 20.

Next, actions and effects according to the first embodiment are listed. (1) Condensed water comes into contact with polyaniline and becomes superoxide anion radical (.O ₂ ⁻ ) → hydrogen peroxide water (H ₂ O ₂ ). Hydrogen water (H ₂ O ₂ ) reacts with the catalyst 21 of the adsorbent layer 20 to generate hydride radicals (.OH). And since this hydride radical (.OH) oxidatively decomposes the odor component adsorbed to the adsorbent layer 20, the odor component in the conditioned air A flowing into the core portion 15 can be purified.

(2) The condensed water comes into contact with polyaniline to generate a superoxide anion radical (.O ₂ ⁻ ). The superoxide anion radical (.O ₂ ⁻ ) oxidizes and decomposes the odor component in the condensed water 19, that is, the odor component adhering to the surface of the core portion 15. It can be prevented from flowing into the room.

  A combination of these operational effects (1) and (2) can prevent the problem of unpleasant odor from the air outlet sensed by the passenger in the passenger compartment.

(3) Since the reduction current is supplied to the polyaniline coating 17, it is possible to continuously generate superoxide anion radical (.O ₂ ⁻ ) → hydrogen peroxide solution (H ₂ O ₂ ) in the condensed water 19, and the odor Oxidative decomposition of the components can be performed continuously.

  FIG. 3 shows the relationship between the energization time from the in-vehicle battery 23 (power source) to the polyaniline and the amount of hydrogen peroxide generated. The amount of hydrogen peroxide generated was measured by the following method.

First, of the aforementioned (A) ~ (E) step, in place of steel catalyst carrying Toray Trading ^R carbon paper TGP-H-120 (adsorbent layer 20), the catalyst does not carry the Toray Torayca ^R carbon paper A catalyst-free test module incorporating TGP-H-120 was prepared. This is because when hydrogen peroxide comes into contact with the catalyst 21, it becomes a hydroxyl radical (.OH), making it impossible to measure the amount of hydrogen peroxide.

Then, this catalyst-free test module was immersed in 100 ml of tap water, and at the same time, the DC power source and the catalyst-free test module were electrically connected. Specifically, the lead wire connected to Toray-made Torayca ^R carbon paper TGP-H-120 (adsorbent layer 20) is connected to the plus side, the lead wire connected to the polyaniline-containing coating 17 is connected to the minus side and the ground, A voltage of 2.5V was applied. 0.5 ml of water was collected every hour of voltage application, and the concentration of hydrogen peroxide generated in the water was measured using an electron spin resonance apparatus (manufactured by JEOL). As is apparent from FIG. 4, when a voltage is applied, a reduction current, that is, an electron is supplied to the polyaniline film 17 to reliably generate hydrogen peroxide as a hydroxyl radical (.OH) generation source. I can say that.

  Furthermore, FIG. 3 shows the decomposition performance of the odor component (organic matter) of the test module of this embodiment (equivalent to the fin 14) and the above-described catalyst-free test module. In this evaluation, a rhodamine dye was used as a test substitute for odor components (organic substances). The evaluation method is as follows.

First, Torayca ^R carbon paper TGP-H-120 (adsorbent layer 20) manufactured by Toray, a test module without a catalyst (this embodiment), was impregnated with 1 ml of an aqueous rhodamine dye solution adjusted to 5 ppm. At this time, the rhodamine dye was completely adsorbed on Torayca ^R carbon paper TGP-H-120 manufactured by Toray.

In addition, the water after the rhodamine dye was adsorbed reached the polyaniline film 17 through the pore Fron ^R membrane (3 cm × 5 cm, manufactured by Sumitomo Electric Fine Polymer). At this point, the DC power supply and the test module were electrically connected.

Specifically, the lead wire connected to Toray-made Torayca ^R carbon paper TGP-H-120 was connected to the plus side, the lead wire connected to the polyaniline film was connected to the minus side and the ground, and a voltage of 2.5 V was applied. . 1 hour after voltage application, Toray-made Torayca ^R carbon paper TGP-H-120 is taken out from the test module, immersed in 100 ml of water at 80 ° C., the adsorbed rhodamine dye is desorbed in water, and UV-visible light spectrophotometer The rhodamine dye concentration was measured using (Shimadzu).

  According to this, in the test module without catalyst, the adsorbed rhodamine dye was hardly decomposed (high absorbance). On the other hand, in the test module carrying the catalyst (fin 14 of the present embodiment), the hydrogen peroxide generated by the polyaniline coating 17 spreads to the adsorbent layer 20 through the moisture permeable layer 18, and It can be said that the reaction generates hydroxy radicals (.OH) to reliably decompose the rhodamine dye.

  Therefore, since a reduction current is supplied to the polyaniline coating 17, hydrogen peroxide is continuously generated (FIG. 4), and this hydrogen peroxide becomes a hydroxy radical (.OH) to continuously oxidize and decompose odor components (FIG. 3). . Thereby, the oxidative decomposition of the odor component can be performed stably and continuously.

(Other embodiments)
In the above-described embodiment, an example is shown in which one fin 14 (base material 16) is arranged in a meandering manner with respect to the tube 11, and the polyaniline-containing coating 17 on the fin 14 is serially fed from the power source 23. Naturally, a reduction current may be supplied in parallel from the power source 23 to the polyaniline-containing film 17 of the plurality of fins 14, respectively.

  In the above-described embodiment, an example in which the polyaniline-containing film 17 and the like are formed on the fins 14 of the core portion 15 has been described. However, the polyaniline-containing film 17 may be disposed on the tube 11. Further, the coating film 17 may be disposed only on a part of the fin 14 and the tube 11.

It is a front view which shows 1st Embodiment which applied this invention to the evaporator. It is an expanded sectional view of the core part of FIG. It is a figure which shows the difference of the rhodamine light absorbency with the case where a catalyst exists in an adsorbent layer, and the case where it does not exist. It is a figure which shows the relationship between the electricity supply time to polyaniline, and the generation amount of hydrogen peroxide. It is an expanded sectional view of the core part of the evaporator concerning patent documents 1.

Explanation of symbols

15 ... Core part (heat exchange part), 16 ... Base material, 17 ... Polyaniline-containing film,
18 ... porous membrane (moisture permeable layer), 19, B ... condensed water (moisture),
20 ... Activated carbon fiber (adsorbent layer), 21 ... Catalyst, 23 ... In-vehicle battery (power source),
A: Air (air for air conditioning).

Claims (9)

A heat exchanging part (15) formed of a base material (16) for exchanging heat between the fluid flowing inside and air (A);
A polyaniline-containing coating (17) containing polyaniline which is disposed so as to cover at least a part of the substrate (16) and generates active oxygen when contacted with moisture;
A moisture permeable layer (18) that is laminated on the polyaniline-containing coating (17) and is permeable to moisture (B, 19) generated in the heat exchange section (15);
An adsorbent layer (20) that is stacked on the moisture permeable layer (18) and adsorbs odorous components in the air (A);
A catalyst (21) carried on the adsorbent layer (20);
A power source (23) electrically connected to the adsorbent layer (20) and the polyaniline-containing coating (17),
A heat exchanger having an air cleaning function, characterized in that a reduction current is supplied to the polyaniline-containing coating (17). The heat exchanger having an air cleaning function according to claim 1, wherein the adsorbent layer (20) is made of activated carbon fiber having conductivity. The heat exchanger having an air cleaning function according to claim 1 or 2, wherein the moisture permeable layer (18) is a porous film having an insulating property. The heat exchanger having an air cleaning function according to any one of claims 1 to 3, wherein the catalyst (21) includes at least one of iron, copper, zinc, and titanium. The heat exchanger having an air cleaning function according to any one of claims 1 to 4, wherein the base material (16) is made of an aluminum alloy or a resin. The air purifier according to any one of claims 1 to 5, wherein the polyaniline in the polyaniline-containing film (17) includes at least one of polyanilines represented by the following chemical formulas 1 to 4. Heat exchanger with function.

(Here, in Chemical Formulas 1 to 4, A represents an anion, n represents an integer in the range of 2 to 5000, and x and y simultaneously satisfy x + y = 1 and 0 ≦ y ≦ 0.5. It is the number to satisfy.) The moisture generated in the heat exchanging section (15) is condensed water (B, 19) in which moisture in the air (A) is condensed. A heat exchanger with an air cleaning function. The air cleaning function according to any one of claims 1 to 7, wherein the fluid flowing through the inside is a refrigerant that evaporates due to heat absorption from the air (A) in a heat exchange section (15). Having a heat exchanger. The power source is an in-vehicle battery (23) mounted on a vehicle,
The heat exchanger having an air cleaning function according to any one of claims 1 to 8, wherein the air (A) is air-conditioning air flowing into a vehicle interior.

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