JP2019007721A - Heat exchanger - Google Patents

Abstract

To provide a heat exchanger capable of suppressing smell felt by a person in an air-conditioned room and the like.SOLUTION: A heat exchanger having polyamine on at least a part of surface is provided. As polyamine exists on the surface of the heat exchanger, smell components are temporarily held by action of polyamine, and the smell components can be prevented from being released to a room and the like at once by interlocking with evaporation of free water (condensate water and the like). Thus the smell components are moderately released, and change of concentration of smell components in the room is reduced, as a result, the person is prevented from strongly feeling smell. A representative example of polyamine is PEI, and a representative example of the heat exchanger is an evaporator for a vehicle air conditioner. This method is echo-making on the point that the smell components are moderately released to prevent and suppress smell, differently from a conventional method by removing and decomposing the smell components.SELECTED DRAWING: Figure 2A

Description

  The present invention relates to a heat exchanger that can suppress odors that a person feels indoors.

  Air conditioners (referred to as “air conditioners”) are usually provided in rooms such as buildings and moving bodies. The air conditioner introduces air that has passed through a heat exchanger into the room to adjust the temperature and humidity in the room.

  People in such rooms may feel odors even without a strong odor source. The cause of such an odor is often an odor component released at a certain timing from an air conditioner (particularly a built-in heat exchanger) in addition to an odor component released from a wall surface or the like.

  As countermeasures against such odors (anti-odor countermeasures and anti-odor countermeasures), the odor components that cause them have been removed by adsorption, decomposition, washing, and the like. Also, in the case of a member (apparatus) that produces a large amount of condensed water on the surface, such as an evaporator for an air conditioner, a treatment agent ((modified) polyvinyl) that has low affinity with odorous substances (odorous components) and excellent hydrophilicity It has also been proposed to perform surface treatment with alcohol or the like. The description relevant to this is, for example, in the following patent document.

Japanese Patent No. 2002-285139 Japanese Patent No. 2002-285140 JP 2003-3282 A JP 2004-293916 A

  When a hydrophilized evaporator as in the above-mentioned patent document is used, the odor component absorbed on the surface is washed out with the condensed water, and the odor component is difficult to accumulate on the surface of the evaporator. However, in reality, even if an evaporator having such a surface treatment is used, if an air conditioner is operated, a person may feel odor at a certain timing. Thus, the conventional deodorizing measures have not always been sufficient.

  This invention is made | formed in view of such a situation, and it aims at providing the heat exchanger which can deodorize or deodorize by the method (mechanism) different from the past.

  As a result of diligent research to solve the above-mentioned problems, the present inventor newly discovered that the presence of polyamine on the surface of the constituent material of the heat exchanger (Al alloy plate) can suppress odors felt by humans. By developing this result, the present invention described below has been completed.

"Heat exchanger"
(1) The present invention is a heat exchanger having a polyamine on at least a part of its surface.

(2) The presence of polyamine on at least a part of the surface of the heat exchanger makes it difficult for a person to feel odor caused by the heat exchanger in a space where the air that has passed through the heat exchanger can be introduced. The mechanism for obtaining such an effect can be considered as follows from the present research.

  First of all, a person senses “odor” by detecting even a very low concentration substance (odor component) by smell. However, human olfaction does not feel the intensity of odors corresponding to the absolute amount (concentration) of odor components, but the amount (concentration) or quality of odor components (the ratio of each odor component mixed) has changed. Sometimes it is easy to feel odor.

  Next, in the case of a heat exchanger, the release (evaporation) of water is largely involved in the release of odor components. Further, many of the released odor components are often absorbed into the water on the surface of the heat exchanger from the atmosphere.

  Based on these findings and the results of the evaluation test described below, the polyamine present on the surface of the heat exchanger temporarily holds odor components and water to suppress their release, and the odor components are contained in the air-conditioned room. Suppresses sudden release (that is, releases odor component slowly). As a result, it is considered that people in the air-conditioned room are less likely to feel the odor caused by the heat exchanger.

<Others>
(1) The heat exchanger of this invention should just have a polyamine on the surface side at least, and the polyamine presence form in the surface of a heat exchanger is not ask | required. Usually, the surface of the heat exchanger is often coated as a polymer film containing polyamine. In this case, the polymer film may be a single polyamine or may contain a polymer, resin, metal, or the like other than polyamine.

  The polyamine referred to in the present invention may be modified, and a part of its end groups are carbonyl group, carboxyl group, imide group, hydroxyl group, nitrile group, nitro group, sulfide group, sulfoxide group, sulfone group, It may be substituted with one or more polar functional groups such as a thiol group and an ester group. The polyamine according to the present invention may be a mixture of a plurality of types of polymers (polymers), or one or more of them may have a graft polymerization structure.

  The polyamine is preferably a chelate structure. Coordination of metal ions can impart antiseptic and antibacterial properties to the heat exchanger. Further, it is preferable that hydrophilicity is imparted to the surface of the heat exchanger. Polyamine itself may exhibit hydrophilicity, and hydrophilicity may be imparted to the surface of the heat exchanger together with another polymer (polymer material).

(2) Unless otherwise specified, “x to y” in this specification includes a lower limit value x and an upper limit value y. A range such as “a to b” can be newly established with any numerical value included in various numerical values or numerical ranges described in the present specification as a new lower limit value or upper limit value.

It is a schematic diagram which shows a mode that a water molecule couple | bonds with the molecule | numerator of the polyethyleneimine which is one of the polyamines. It is explanatory drawing which showed typically the mechanism which feels odor. It is explanatory drawing which showed typically the mechanism by which an odor component is discharge | released. It is a schematic diagram which shows the outline | summary of the apparatus used for the odor evaluation test. It is the graph obtained by the evaluation test which concerns on 1st Example. It is the graph obtained by the evaluation test which concerns on 2nd Example. It is a graph which shows the thickness of the hydration layer in the surface of the test material used for the evaluation test.

  One or two or more components arbitrarily selected from the present specification may be added to the above-described components of the present invention. A method component can also be a component of an object in certain cases. Which embodiment is the best depends on the target, required performance, and the like.

《Polyamine》
(1) Structure A polyamine is a polymer having an amino group. For example, there is a linear aliphatic hydrocarbon having three or more primary amino groups bonded thereto. A further specific example is polyethyleneimine (PEI).

The molecular formula of PEI is (—CH ₂ —CH ₂ —NH—) n, and has a molecular structure as shown in FIG. The amino group (—NH—), which is the main functional group, is a polar group, and the distance between adjacent areas (distance between adjacent N) is about 3.7 mm. The molecular diameter of water hydrogen-bonded to the amino group is about 2 mm. From this viewpoint, it is preferable that the distance between adjacent amino groups in the polyamine is 2 to 4 mm, and further 2.5 to 3.5 mm.

(2) Water characteristics Polyamine exists so as to grow on the substrate surface of the heat exchanger, and includes one to several molecules of water. The water contained by the polyamine is electrically strongly bonded to the polyamine and is not easily separated (evaporated, desorbed, etc.) from the polyamine unless heated to a boiling point or higher even when heated to a high temperature. On the other hand, on the surface side, according to changes in the environment (temperature and humidity of the atmosphere) to which the surface of the heat exchanger is exposed, condensed water (condensed water) that can move freely is easily generated, Evaporate.

  In the present specification, as appropriate, water that is included in the polyamine and is not easily released is “bound water”, water that is easily generated or evaporated from the polyamine is “free water”, Water in the transition zone that exhibits intermediate characteristics between the two is called “intermediate water”. In the case of a heat exchanger (especially an evaporator), a representative example of free water is “condensed water” (condensed water) in which water vapor in the air has condensed, and intermediate water can be rephrased as “adsorbed water”. In this specification, “condensed water” is used synonymously with “free water”, and “adsorbed water” is used synonymously with “intermediate water”.

  Incidentally, the combined water / intermediate water (also referred to as a hydrated layer) formed on the polyamine preferably has a thickness of 20 to 90 nm, more preferably 30 to 70 nm. If the thickness is too small, the sustained release effect becomes weak, and it is difficult to form excessively thick bound water / intermediate water. The thickness of the hydration layer bonded on such a polyamine is specified by a scanning probe microscope (SPM).

(3) Smell characteristics Smell components can be released on the surface of a heat exchanger substrate (for example, an Al alloy fin) as shown in FIG. 2A. First, when there is no polyamine on the surface of the base material, as shown in FIG. 2A (1), the odor component is dissolved and absorbed in free water (for example, condensed water such as condensed water) generated on the surface of the base material. It becomes a concentrated state. When free water evaporates due to a decrease in humidity or an increase in temperature of the atmosphere to which the substrate surface is exposed, an odorous component is also released into the atmosphere at the same time as the free water evaporates. Thereby, the density | concentration of the odor component in atmosphere increases rapidly, and the person in it comes to feel odor strongly.

  Next, when polyamine is present on the base material surface of the heat exchanger, as shown in FIG. 2A (2), the odor component becomes free water (for example, condensed water such as condensed water) generated on the base material surface. It will be dissolved and absorbed and taken up. This is the same as in the case where the polyamine is not present.

  However, many of the absorbed and concentrated odor components are organic substances, and they are often macromolecules having polarity, many of which are captured by the polar groups of polyamines by electrical attraction. It becomes. As a result, even if the free water on the polyamine evaporates, the odor component is not released all at once. This is one difference from the case where no polyamine is present as shown in FIG. 2A (1).

  Further, the intermediate water / bonded water remaining in the vicinity of the polyamine after evaporation of free water is less likely to evaporate than free water, and the bond water hardly evaporates. Therefore, the odor component moved to the hydrated layer composed of intermediate water and combined water by evaporation of free water is not released into the atmosphere at once. This point is also different from the case where no polyamine is present as shown in FIG. 2A (1).

  Furthermore, when polyamine is present, water in the hydrated layer is gradually evaporated, and accordingly, the odor component is gradually released. Therefore, when polyamine is present, the odor component is not excessively concentrated in the hydrated layer.

  If free water or water in the hydrated layer evaporates and free water is generated again, some of the low-concentration odor components that are temporarily retained in the hydrated layer move to the free water. (Distributed), the hydration layer does not continue to accumulate odors because it is in a lower concentration state.

  Such a phenomenon is repeated on the polyamine present on the substrate surface of the heat exchanger, and by acting synergistically, the odor component is not released into the atmosphere at once (that is, slowly released) It seems that the strong sense of odor has been suppressed.

(4) Release behavior of odorous component on evaporator The state of odorous component being released slowly by the presence of polyamine on the substrate surface of the heat exchanger (release behavior of odorous component) is concretely shown in FIG. 2B. Detailed description. FIG. 2B schematically shows the release behavior of an odor component when PEI, which is a typical example of polyamine, is present on an evaporator, which is a typical example of a heat exchanger.

  As shown in FIG. 2B (1), when the air conditioner is turned on and the compressor starts operating, the compressed refrigerant adiabatically expands in the evaporator, and the surface temperature of the evaporator decreases. As a result, the air in contact with the surface of the evaporator is cooled, and the water vapor contained in the air is condensed on the surface and becomes free water (condensed water, condensed water). And the odor component contained in the air which contacts an evaporator is taken in by dissolving or absorbing in the free water. A part of the odor component taken into the free water also moves to a hydrated layer composed of intermediate water and bound water immediately below the free water (on the substrate surface side). Thus, the concentration of the odor component in each water is in an equilibrium state within a range that can be included in the water of each layer.

  As shown in FIG. 2B (2), when the compressor of the air conditioner stops operating, the surface temperature of the evaporator starts to rise, and the free water on the surface evaporates (discharges) accordingly. At this time, the odor component dissolved and absorbed in the free water is released into the room together with the free water vapor (water molecules). However, as described above, a part of the odor component taken into the free water is transferred (distributed) to the hydrated layer composed of intermediate water and combined water. For this reason, in conjunction with the evaporation of free water, highly concentrated odor components are not released into the air-conditioned room. Furthermore, the hydrated layer composed of intermediate water and bound water is electrically attracted from the PEI side, and is unlikely to evaporate freely like free water. For this reason, even if free water evaporates, the odor component which has moved to the hydration layer is not released into the room at once.

  As shown in FIG. 2B (3), when the compressor is restarted, free water is generated again on the surface of the evaporator. Odor components contained in the air gradually decrease due to the cleaning of the evaporator surface accompanying the outflow of free water. As a result, when the concentration of the odorous component taken into the free water also decreases, the odorous component temporarily retained in the hydrated layer moves to the free water on the contrary, and the concentration of the odorous component is totally reduced. It becomes an equilibrium state.

  As shown in FIG. 2B (4), when the free water evaporates due to the restart of the compressor, the odor component transferred from the hydrated layer to the free water is also released in conjunction with the evaporation. Naturally, the concentration of the odor component released at this time is relatively low.

  As shown in FIG. 2B (5), when free water evaporates and the amount of free water decreases, the water in the hydrated layer also gradually begins to evaporate. In conjunction with the evaporation, the odor component contained in the hydrated layer is also released. Also in this case, since there are not many odor components contained in the hydrated layer, the concentration of the odor components released by the evaporation is also low.

  After this, a hydration layer is newly generated, and when odor components are taken in from the air in contact with the evaporator via free water, etc., the hydration layer consisting of intermediate water / bonded water with reduced concentration of odor components, Again, part of the odor component migrates and is retained. Then, the cycle shown in FIG. 2B (1) and FIG. 2B (2) described above is repeated again.

  In any case, the PEI present on the surface of the evaporator substrate has a polarity capable of temporarily holding the odor component and generates a hydrated layer, so that the odor component is released into the air-conditioned room at once. Hindering. As a result, the odor component is gradually released into the air-conditioned room, and the concentration change of the odor component in the air-conditioned room becomes gradual, and a person in the air-conditioned room does not feel a strong odor.

(5) Molecular Weight The reason why polyamine exhibits the sustained release action of odor components is due to its molecular structure. When the molecular weight changes, the thickness of the hydration layer and the like change, and the sustained release effect of the odor component can also change. For example, as the molecular weight increases, the thickness of the hydration layer increases, and the sustained release effect and thus the deodorizing effect tends to increase. Therefore, the molecular weight of the polyamine is preferably 300 to 70000, more preferably 400 to 35000. Polyamines with too low or too high molecular weight are not readily available. Further, when the molecular weight is too small, the sustained release effect is weakened, and when the molecular weight is too large, the viscosity becomes high and adhesion to the substrate surface becomes difficult.

  The molecular weight as used herein is a well-known Z average molecular weight (Mz), and the molecular weight is calculated by Mz = ΣMi3Ni / ΣMi2Ni (Mi: each molecular weight, Ni: molecular number of molecular weight Mi).

(6) Adhesion For example, the polyamine may exist as a polyamine alone on the surface of the base material of the heat exchanger, or may coexist with one or more other polymers or surfactants. Examples of polymers mixed with polyamines include polar functional groups such as amino groups, carbonyl groups, carboxyl groups, imide groups, hydroxyl groups, nitrile groups, nitro groups, sulfide groups, sulfoxide groups, sulfone groups, thiol groups, and ester groups. It is good to use what has 1 or more types.

  The form of adhesion of the polyamine to the substrate surface is not limited. It may be attached only to the surface layer of the polymer film, may be attached to the entire film including the inside of the polymer film, or may be a polymer film made of a composite component. Furthermore, the region (part) to which the polyamine is attached may be a part or all of the heat exchanger. Since the heat exchanger includes a large number of fine air passages, a coating method, a dipping method, or the like is appropriately selected as a polyamine adhesion (film formation) method according to the shape of the heat exchanger.

"Heat exchanger"
The heat exchanger includes a flow path through which a heat medium flows and air fins disposed around the flow path. The heat exchanger is typically an evaporator, but may be a condenser, a radiator or the like as long as deodorization / deodorization is required, and is not necessarily used for air conditioning. Furthermore, the heat exchanger and the equipment provided with the heat exchanger may be used either in a moving body (automobile, railway vehicle, aircraft, ship, etc.), at home, in a business office, or the like.

  A test to evaluate the odor generated from each sample by preparing various samples to which odor components are attached, assuming that it is difficult for people in the passenger compartment to feel the odor generated from the car air conditioner (especially an evaporator). went. The present invention will be described in more detail based on such specific examples.

[First embodiment]
"sample"
(1) Base Material A silicate glass plate (simply referred to as “glass plate” / sample 11) was prepared as a base material (test piece) to which an odor component was adhered. The base material size was 16 × 76 × 1 mm.

(2) Polymer film The surface of the glass plate was coated with a polymer film made of PEI which is a typical example of polyamine (simply referred to as “PEI film”). The film was formed by introducing glycidyltrimethoxysilane into silanol groups on the glass plate surface and attaching PEI to the glass plate surface.

(3) Odor Component Acetic acid, butyric acid, and trimethylamine (TMA) were used as the odor components to be attached to the substrate. Both are typical odor substances made of organic substances. Each base material was immersed in a mixed aqueous solution of these odor components (acetic acid: 1000 ppm, butyric acid: 100 ppm, TMA: 1000 ppm) for 3 days. The substrate pulled up from the mixed aqueous solution was sufficiently washed with pure water and then naturally dried indoors. Each sample thus obtained was subjected to odor evaluation.

"test"
The odor component release behavior of each sample was examined using a test apparatus as shown in FIG. Specifically, first, a sample to which an odor component was attached was placed in a glass chamber, and N ₂ conditioned using a mass flow meter and a humidifier was introduced into the chamber. This chamber was alternately immersed in a high temperature (30 ° C.) thermostat and a low temperature (2 ° C.) thermostat to change the environment in the chamber (temperature and humidity in the vicinity of the surface of each specimen). At this time, the high temperature holding time: 15 minutes, and the low temperature holding time: 15 minutes.

  The air that passed through this chamber and was led to the outlet was measured for humidity change and sensory evaluation (odor intensity evaluation). Along with this sensory evaluation, the air was collected in a collection tube, and the concentration analysis of each odor component was also performed using a gas chromatograph-mass spectrometer (GC / MS). The results thus obtained are also shown in FIG.

  The upper part of FIG. 4 shows the humidity of the air introduced into the chamber (WET / DRY), the holding temperature of the chamber, and the humidity of the air derived from the discharge port (sensory evaluation port). The middle and lower parts of FIG. 4 also show the sensory evaluation results and the GC / MS measurement results for sample 11 (with PEI film) and sample C0 (without PEI film / details will be described later). It was.

<Evaluation>
As is clear from FIG. 4, it was revealed that the release behavior of the odor component differs depending on the presence or absence of the PEI film. Specifically, the sample 11 with the PEI film showed a gentle change in both the odor component concentration and the sensory evaluation by GC / MS compared to the sample C0 without the PEI film. That is, it has been clarified that the odor component is gradually released by the PEI film, which makes it difficult to feel the odor.

[Second Embodiment]
"sample"
An aluminum alloy plate (simply referred to as “Al alloy plate” / sample C0) was prepared as a base material to which the odor component was adhered. This aluminum alloy plate is for a heat exchanger (evaporator), and is obtained by surface-treating an aluminum alloy (A1050) with a hydrophilic resin. The size of each substrate was 16 × 76 × 0.2 mm.

  In addition to the Al alloy plate (Sample C0), Sample 21 (PEI molecular weight: 600) and Sample 22 (PEI molecular weight: the surface of the Al alloy plate coated with a polymer film (PEI film) made of PEI having different molecular weights) 10,000). Each PEI film was formed in the same manner as in the first example.

  The odor component was made to adhere to each sample like the case of 1st Example. Each sample thus obtained was subjected to odor evaluation.

"test"
(1) The same sensory evaluation (odor intensity evaluation) as in the case of the first example was performed for each test material. The obtained results are also shown in FIG. The upper part of FIG. 5 shows the chamber temperature and the humidity at the discharge port (sensory evaluation port). The lower part of FIG. 5 shows the sensory evaluation results for each sample.

(2) Using an atomic force microscope (AFM: SPM-8000FM, manufactured by Shimadzu Corporation), which is a kind of scanning probe microscope (SPM), is on the surface of the specimen (before the sensory evaluation test) of each sample. The thickness of the hydration layer was measured. The results obtained by this are shown in FIG.

<Evaluation>
(1) As is clear from FIG. 5, the sample C0 without the PEI film showed a sharp peak odor intensity. On the other hand, in the samples 21 and 22 having the PEI film, the odor intensity was significantly reduced, and the change in the odor intensity became gentle. This tendency was more prominent for samples with a larger amount of amino groups introduced.

(2) From FIG. 6, it was found that the thickness of the hydrated layer generated on the surface of the test material was sample C0: 9 nm, sample 21:30 nm, and sample 22: 50 nm. As a result, it became clear that as the molecular weight of PEI increased, the thickness of the hydrated layer formed on the surface of the test material also increased, and the odor intensity was reduced and the change in odor intensity was suppressed. .

(3) Further, from FIG. 5, it was also clarified that the timing at which the odor intensity reaches the maximum (peak) is different for each sample. Specifically, in the sample C0 without the PEI film, the odor intensity was maximized in the vicinity where the humidity at the discharge port was maximized. On the other hand, in the samples 21 and 22 having the PEI film, the odor intensity was maximized after a time when the humidity at the discharge port was maximized. As described above, the maximum values of the samples 21 and 22 were significantly reduced as compared with the sample C0.

(4) The reason why such a tendency is obtained is considered as follows. In the sample C0 without the PEI film, it is considered that the release of the odor component is linked to the evaporation of water from the surface of the test material. On the other hand, in the samples 21 and 22 having the PEI film, it is considered that the release of the odor component is not necessarily interlocked with the evaporation of water, and the odor component is gradually released (that is, gradually released) by the PEI film.

  In addition, as the sample is formed with PEI having a higher molecular weight, the maximum value of the odor intensity is reduced and the timing at which the odor intensity is maximized is delayed. One reason for this is considered to be that the higher the molecular weight of PEI, the thicker the hydrated layer can be formed on the substrate surface, and the more odorous components can be temporarily retained.

  In any case, due to the presence of polyamine on the surface of the heat exchanger substrate, the odorous component is released slowly (slow release), and the odorous component remains even if the ambient environment (humidity, temperature, etc.) changes. It was revealed that human beings feel odor strongly without being released suddenly.

Claims (7)

  A heat exchanger having a polyamine on at least a part of its surface.   The heat exchanger according to claim 1, wherein the polyamine has a molecular weight of 300 to 70000.   The heat exchanger according to claim 1 or 2, wherein the polyamine has a distance between adjacent amino groups of 2 to 4 mm.   The heat exchanger according to claim 1, wherein the polyamine includes a hydration layer having a thickness of 20 to 90 nm.   The polyamine has a functional group further having one or more functional groups selected from carbonyl group, carboxyl group, imide group, hydroxyl group, nitrile group, nitro group, sulfide group, sulfoxide group, sulfone group, thiol group or ester group. The heat exchanger according to any one of claims 1 to 4, which is a coalescence.   The heat exchanger according to claim 1, wherein the polyamine contains at least polyethyleneimine (PEI).   It is an evaporator, The heat exchanger in any one of Claims 1-6.