Polymer desiccant material, manufacturing method, waste heat recovery device, and polymer desiccant material with cobalt chloride

Abstract

To provide a polymer desiccant material that allows for good visual confirmation of moisture content. [Solution] The polymer desiccant material with cobalt chloride is manufactured by immersing the polymer desiccant material in a cobalt chloride solution with a cobalt chloride concentration of 2000 ppm to 10000 ppm for an immersion time of 5 minutes to 60 minutes.

Description

Technical Field

[0001] The present disclosure relates to a polymer desiccant material, a manufacturing method, a waste heat recovery device, and a polymer desiccant material with cobalt chloride.

Background Art

[0002] Conventionally, there is a technique for visually confirming the amount of moisture contained in a water-absorbent material (for example, Patent Document 1). The humidity-sensitive discoloring sheet of the pet sheet of Patent Document 1 is a water-absorbent pulp containing cobalt chloride that changes color depending on the amount of moisture.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Depending on the type of water-absorbent material, the retention state of cobalt chloride with respect to the water-absorbent material changes. There has been no clarification of a polymer desiccant material that can satisfactorily retain cobalt chloride in a polymer desiccant material, which is a water-absorbent material, and can satisfactorily perform visual confirmation of the amount of moisture.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to the first embodiment of this disclosure, a polymer desiccant material is provided. This polymer desiccant material is produced by immersing the polymer desiccant material in a cobalt chloride solution having a cobalt chloride concentration of 2,000 ppm to 10,000 ppm for an immersion time of 5 minutes to 60 minutes to deposit cobalt chloride. According to this embodiment, a polymer desiccant material with cobalt chloride that changes color depending on whether it is in a dry or wet state can be provided. With this polymer desiccant material with cobalt chloride, it is possible to easily visually confirm the amount of moisture sorbed onto the polymer desiccant material. (2) In the polymer desiccant material of the above form, the solvent of the cobalt chloride solution may contain at least one selected from the group consisting of (a) monohydric alcohols having 2 or more carbon atoms, (b) ketones, (c) cyclic ethers, and (d) carboxylic acids excluding formic acid and oleic acid. According to this form, a cobalt chloride solution can be prepared that can successfully attach cobalt chloride to the polymer desiccant material. (3) In the polymer desiccant material of the above form, the solvent may include at least one selected from the group consisting of (a) ethanol, propanol, butanol, and 1-octanol, (b) cyclohexanone and acetone, (c) tetrahydrofuran, and (d) acetic acid. According to this form, a cobalt chloride solution can be prepared that can further better attach cobalt chloride to the polymer desiccant material. (4) In the polymer desiccant material of the above form, the solvent of the cobalt chloride solution may be ethanol. According to this form, a cobalt chloride solution can be prepared that can further improve the adhesion of cobalt chloride to the polymer desiccant material. (5) In the polymer desiccant material of the above form, the concentration of the cobalt chloride solution may be 4000 ppm, and the immersion time may be 10 minutes or more and 60 minutes or less. According to this form, a polymer desiccant material with cobalt chloride can be produced in which the color change between the dry state and the wet state is easily visible. (6) A second embodiment of the present disclosure provides a waste heat recovery device. This waste heat recovery device comprises a polymer desiccant material, at least one mesh tray on which the polymer desiccant material is arranged, a cylindrical side wall surrounding the at least one tray, and an opening positioned between the at least one tray and the equipment. In this embodiment, when the waste heat recovery device is placed on the equipment, air flows into the interior of the housing from the opening and out to the outside of the housing. The rising heated air generated in the housing space surrounded by the side wall causes the polymer desiccant material to desorb water. Since the polymer desiccant material absorbs heat from its surroundings in the process of desorbing water molecules, the waste heat recovery device can be used as a heat removal device. The polymer desiccant material with cobalt chloride changes color depending on the amount of moisture, so the amount of moisture adsorbed on the polymer desiccant material can be visually confirmed. (7) A third embodiment of the present disclosure provides a method for manufacturing. This method involves preparing a cobalt chloride solution with a cobalt chloride concentration of 2,000 ppm or more and 10,000 ppm or less, immersing a polymer desiccant material in the cobalt chloride solution for an immersion time of 5 minutes or more and 60 minutes or less, and drying the polymer desiccant material. This embodiment provides a cobalt chloride-coated polymer desiccant material that changes color between a dry state and a wet state. (8) According to a fourth embodiment of the present disclosure, a polymer desiccant material with cobalt chloride is provided. This polymer desiccant material with cobalt chloride has a color difference of 14 or more in the CIEL*a*b* color space between a wet state and a dry state. According to this embodiment, the color change between the dry state and the wet state is easily visible, so that the amount of moisture adsorbed on the polymer desiccant material can be easily visually confirmed. This disclosure can be implemented in various forms, and in addition to the polymer desiccant material with cobalt chloride described above, it can also be implemented in forms such as a method for manufacturing the polymer desiccant material with cobalt chloride, a method for manufacturing a waste heat recovery device, and a method for using it. [Brief explanation of the drawing]

[0007] [Figure 1]This is a flowchart showing the manufacturing method for a polymer desiccant material with cobalt chloride. [Figure 2] Table 1 summarizes the experimental results regarding the dissolution of cobalt chloride solution. [Figure 3] This is the second table, summarizing the experimental results regarding the dissolution of cobalt chloride solution. [Figure 4] This table summarizes the mass of cobalt chloride in each sample of cobalt chloride solution. [Figure 5] This is the first table summarizing the experimental results regarding color difference. [Figure 6] This is the second table summarizing the experimental results regarding color difference. [Figure 7] This is a perspective view of the waste heat recovery device 1. [Figure 8] This is a cross-sectional view taken along line VIII-VIII in Figure 7. [Modes for carrying out the invention]

[0008] A. Embodiments: Figure 1 is a flowchart showing the steps of the manufacturing process for realizing the method for producing the cobalt chloride-coated polymer desiccant material 90. In step S1 of Figure 1, a cobalt chloride solution is prepared. Specifically, powdered cobalt chloride is placed in a solvent and stirred to prepare a cobalt chloride solution.

[0009] The solvent comprises at least one selected from the group consisting of (a) monohydric alcohols having 2 or more carbon atoms, (b) ketones, (c) cyclic ethers, and (d) carboxylic acids excluding formic acid and oleic acid. This makes it possible to prepare a cobalt chloride solution that can effectively attach cobalt chloride to the polymer desiccant material 90. The solvent is preferably at least one selected from ethanol, 1-propanol, 2-propanol, 1-butanol, 1-octanol, cyclohexanone, tetrahydrofuran, and acetic acid, and more preferably ethanol. This makes it possible to prepare a cobalt chloride solution that can even more effectively attach cobalt chloride to the polymer desiccant material 90.

[0010] The concentration of cobalt chloride in the cobalt chloride solution is preferably higher than 2000 ppm and lower than 10000 ppm, and more preferably 4000 ppm. Thereby, the polymer desiccant material 90 with cobalt chloride, in which the color change between the dry state and the wet state can be easily visually recognized, can be produced. The concentration [ppm] is the concentration at room temperature and is calculated by the following formula (1). Concentration [ppm]=a / (a + b)×10 6 ··(1) However, in formula (1), a is the mass [g] of cobalt chloride, and b is the mass [g] of the solvent.

[0011] In step S3, the produced cobalt chloride solution is immersed in the polymer desiccant material 90. As the polymer desiccant material 90, for example, a polyacrylic acid-based organic polymer can be used. The polymer desiccant material 90 can take in moisture in the air by using the hydrophilic groups of the polymer chain as adsorption sites for water molecules. In this embodiment, sodium polyacrylate is used as the polymer desiccant material 90.

[0012] The immersion time in step S3 is preferably 5 minutes or more and 60 minutes or less, more preferably 10 minutes or more and 60 minutes or less, and even more preferably 10 minutes or more and 15 minutes or less. Thereby, the polymer desiccant material 90 with cobalt chloride, in which the color change between the dry state and the wet state can be easily visually recognized, can be produced.

[0013] In step S5, the polymer desiccant material 90 is separated and dried. Specifically, the polymer desiccant material 90 separated from the cobalt chloride solution is placed in a constant temperature bath at 60°C for about 15 minutes to 60 minutes. Thereby, the polymer desiccant material 90 with cobalt chloride is produced.

[0014] The manufactured polymer desiccant material 90 with cobalt chloride exhibits a blue color in the dry state and a red color in the wet state. Therefore, according to this polymer desiccant material 90 with cobalt chloride, the amount of moisture adsorbed by the polymer desiccant material 90 can be visually confirmed.

[0015] B. Sample Examples and Evaluation Results: Figures 2 and 3 are tables summarizing the experimental results regarding the dissolution of cobalt chloride solution. Figure 4 is a table summarizing the mass of cobalt chloride in the cobalt chloride solution. The cobalt chloride used was 7646-79-9 · Cobalt(II) Chloride · 035-10982 manufactured by Fujifilm Wako. The polymer desiccant material 90 used in the experiment was spherical sodium polyacrylate manufactured by Nippon Exelan Industry Co., Ltd.

[0016] Samples 1 to 21 shown in Figures 2 and 3 were prepared by putting cobalt chloride in each solvent and stirring at room temperature. Samples 1 to 21 have different solvents from each other. The solvents used in each sample are as shown in Figures 2 and 3. The amount of the solvent is 1 ml for all of Samples 1 to 21. The mass of cobalt chloride, which is the solute used in each sample, is as shown in Figure 4.

[0017] After preparing the cobalt chloride solution, the degree of dissolution was evaluated as "A" and "B". In the "Dissolution Evaluation" shown in Figures 2 and 3, the evaluation "A" indicates that cobalt chloride has dissolved. The evaluation "B" indicates that cobalt chloride did not dissolve in the solvent. From this result, it can be seen that ethylene glycol, glycerin, oleic acid, ethyl acetate, hexane, toluene, and aqueous ammonia are not suitable as solvents.

[0018] In Figure 3, the description of "Solution Color" for "Sample 18" as "Pale Blue / Grayish Cloudiness" indicates that immediately after stirring, the solution appeared pale blue, and over time, a grayish cloudiness developed. Similarly, for "Solution Color" of "Sample 19" in Figure 3, the solution appeared khaki immediately after stirring, and over time, it appeared an intermediate color between brown and green.

[0019] Cobalt(II) chloride, a chloride of divalent cobalt, has different colors depending on its hydration number, which is the number of water molecules hydrating it. Hereafter, "cobalt(II) chloride" will be simply referred to as "cobalt chloride." Cobalt chloride with "0" water of hydration, i.e., anhydrous cobalt chloride, is blue. Cobalt chloride with "6" water of hydration is red. As the hydration number increases from "0" to "6," the color of cobalt chloride changes gradually from blue to red.

[0020] The present invention aims to produce a polymer desiccant material 90 whose color changes according to the amount of water adsorbed onto it. Therefore, it is preferable to select a solvent in which the cobalt chloride solution turns blue. This makes it possible to obtain a blue cobalt chloride-coated polymer desiccant material 90. In addition, it is possible to obtain a cobalt chloride-coated polymer desiccant material 90 that changes color closer to red as the amount of water adsorbed onto the polymer desiccant material 90 increases.

[0021] The "Overall Evaluation" shown in Figures 3 and 4 indicates that an "A" rating is good and a "B" rating is poor. An "Overall Evaluation" of "A" was given when the "Dissolution Evaluation" was "A" and the "Solution Color" was "Cobalt Blue," while all other cases were given a "B" rating. From the results shown in Figures 3 and 4, it can be seen that ethanol, 1-propanol, 2-propanol, 1-butanol, 1-octanol, cyclohexanone, acetone, tetrahydrofuran, and acetic acid are suitable solvents.

[0022] Incidentally, it is known that the color of cobalt chloride solution varies depending on the solvent, but the reason for this has not been determined. For example, when the solvent is distilled water, the reason the solution turns red is due to the presence of Co(H2O)6 in the aqueous solution. 2+ It is believed that these factors are responsible for the following: For example, when the solvent is an alcohol, the reason the solution turns blue is thought to be due to CoCl2X2 (where X is an alcohol molecule) in the aqueous solution. For example, when the solvent is methanol, the reason the solution turns purplish-red is thought to be due to the presence of CoCl2X4 (where X is an alcohol molecule) in addition to CoCl2X2 (where X is an alcohol molecule) in the aqueous solution.

[0023] Figures 5 and 6 are tables summarizing the experimental results regarding the color difference of the cobalt chloride-coated polymer desiccant material 90. Samples 31 to 39 shown in Figures 5 and 6 were prepared by the manufacturing method described above. In all of the samples from 31 to 39, the solvent for the cobalt chloride solution was ethanol. The polymer desiccant material 90 used in the experiment was granular sodium polyacrylate. The polymer desiccant material 90 without cobalt chloride is cream-colored.

[0024] Samples 31 through 39 differ from each other in either the concentration of the cobalt chloride solution or the immersion time. Specifically, samples 31 through 33 have a cobalt chloride solution concentration of 2000 ppm. Samples 34 through 36 have a cobalt chloride solution concentration of 4000 ppm. Samples 37 through 39 have a cobalt chloride solution concentration of 10000 ppm. The method for calculating the concentration is the same as described above.

[0025] For samples 31, 34, and 37, the immersion time in step S3 of Figure 1 is 5 minutes. For samples 32, 35, and 38, the immersion time is 15 minutes. For samples 33, 36, and 39, the immersion time in step S3 of Figure 1 is 60 minutes.

[0026] The drying conditions in step S5 of Figure 1 were the same for all samples from Sample 31 to Sample 39. Specifically, they were dried in a constant temperature bath at 60°C for 60 hours.

[0027] For each sample, the lightness and chromaticity of the sample in a dry state and in a wet state were measured using a chromatometer. The light source of the chromatometer used for measurement was an Ocean Optics DH-2000-BAL UV-VIS-LIGHTSOURCE, the spectrometer was a QE65000, and the software used for measurement and analysis was SPECTRASUITE. Relative reflectance measurements were also performed to measure specular reflection, with the reflectance of the standard white plate (PTFE) set to 100%, and the integration time set to 5 seconds. The lightness (L*), chromaticity (a*), and chromaticity (b*) shown in Figures 5 and 6 are lightness and chromaticity in the CIE1976 L*a*b* color space. For each of the lightness (L*), chromaticity (a*), and chromaticity (b*), the value to the left of the slash ( / ) is the measurement value in the dry state, and the value to the right of the slash ( / ) is the measurement value in the wet state. Furthermore, for each sample, the color difference (ΔE*ab) between the chromaticity in the dry state and the chromaticity in the wet state was calculated. Here, in this application, "dry state" refers to the state after the sample has been dried in a constant temperature bath at a temperature of 60°C and a relative humidity of 10%. In this application, "wet state" refers to the state after the sample in the "dry state" has been removed from the constant temperature bath and left to stand for 60 minutes or more in a room at room temperature with a relative humidity of approximately 40% to 60%.

[0028] For each sample, the saturation of the dry sample and the saturation of the wet sample were measured using the above-described chromaticity measuring device under the above conditions. In the saturation shown in Figures 5 and 6, the value to the left of the slash ( / ) is the measurement value in the dry state, and the value to the right of the slash ( / ) is the measurement value in the wet state.

[0029] In Figures 5 and 6, "Evaluation" indicates that "A" is good and "B" is worse than "A". Perceptual color differences vary depending on the lightness and chromaticity of the color and from person to person, but it is generally said that when the color difference (ΔE*ab) is 14 or more, people clearly recognize that the colors are different. Therefore, in Figures 5 and 6, a color difference (ΔE*ab) of 14 or more is rated "A", and everything else is rated "B". It is also said that even if the color difference (ΔE*ab) is less than 14, if the color difference (ΔE*ab) is greater than 6, people will recognize that there is a difference in color. The inventors confirmed through sensory evaluation that they could recognize the difference in color between the dry and wet states for all the samples shown in Figures 5 and 6.

[0030] As shown in Figures 5 and 6, when the cobalt chloride concentration is 4000 ppm and the immersion time is between 15 and 60 minutes, a cobalt chloride-coated polymer desiccant material 90 with easily discernible color differences between dry and wet states can be produced. It is also considered that concentrations within a range of ±10% of 4000 ppm may be acceptable for producing a cobalt chloride-coated polymer desiccant material 90 with easily discernible color differences between dry and wet states.

[0031] Although the solvent used in samples 31 to 39 was ethanol, similar results are expected to be obtained with other solvents as described above. Furthermore, although the polymer desiccant material 90 used in the experiment was granular, similar results are expected to be obtained with other shapes such as honeycomb, blocks, or sheets.

[0032] Next, we will describe an application of the cobalt chloride-containing polymer desiccant material 90 in the waste heat recovery device 1. Note that the application of the cobalt chloride-containing polymer desiccant material 90 is not limited to the waste heat recovery device 1. For example, the cobalt chloride-containing polymer desiccant material 90 alone can be used as a desiccant that absorbs moisture. Regardless of the application, the cobalt chloride-containing polymer desiccant material 90 allows for good visual confirmation of the amount of absorbed moisture by observing its color.

[0033] C. Waste heat recovery system: Figure 7 is a perspective view of the waste heat recovery device 1. Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 7. Figure 7 shows arrows indicating the mutually orthogonal X, Y, and Z directions. The X and Y directions are parallel to the horizontal plane, and the Z direction is along the vertically upward direction. In other figures, arrows indicating the X, Y, and Z directions are shown as appropriate, so that the directions shown correspond to those in Figure 7. In the following explanation, when specifying the direction, the direction indicated by the arrow in each figure will be denoted as "+" and the opposite direction as "-", and positive and negative signs will be used in the direction notation. Hereafter, the +Z direction will also be called "up", and the -Z direction will be called "down". The axial direction along the Z direction will also be called the up and down direction.

[0034] As shown in Figure 7, the waste heat recovery device 1 is placed on top of the equipment FA that releases heat. In this embodiment, the equipment FA is a heating furnace with a maximum internal temperature set to approximately 1000°C. The maximum temperature of the upper surface of the housing of the equipment FA on which the waste heat recovery device 1 is installed is approximately 90°C. Note that the equipment FA is not limited to a heating furnace, but may be other equipment such as a machine tool. The waste heat recovery device 1 uses the heat released from the equipment FA to regenerate the cobalt chloride-containing polymer desiccant material 90 stored inside. In the following description, the cobalt chloride-containing polymer desiccant material 90 will be simply referred to as "desiccant material 90".

[0035] The waste heat recovery device 1 comprises a plurality of trays 10 as shown in Figure 7, a side wall 50, a roof 60, and a first opening 51 and a second opening 52 as openings. The waste heat recovery device 1 further comprises a support section 40 as shown in Figure 8. The side wall 50 and the roof 60 together are called the housing 20. As shown in Figure 7, the planar shape of each tray 10 when viewed along the vertical direction is rectangular. Each tray 10 is mesh-like. As shown in Figure 8, in this embodiment, each tray 10 has a tray frame 11 and a mesh-like tray bottom surface 12. The tray frame 11 surrounds the tray bottom surface 12. As shown in Figure 8, the tray frame 11 is supported by the support section 40. Typically, the waste heat recovery device 1 is positioned and used so that the tray bottom surface 12 of the trays 10 is horizontal. Desiccant material 90 is placed on the tray bottom surface 12.

[0036] The desiccant material 90 requires a regeneration temperature of approximately 40°C to 100°C to desorb the sorbed water molecules. Therefore, the desiccant material 90 can be regenerated using the heat released from the equipment FA. Solvation is a phenomenon in which absorption and adsorption occur simultaneously. Regeneration of the desiccant material 90 refers to the desorption of the sorbed water molecules. In the process of desorbing water molecules, the desiccant material 90 absorbs heat from its surroundings. Therefore, the waste heat recovery device 1 also functions as a heat removal device. Thus, by installing the waste heat recovery device 1 on top of the equipment FA, the temperature rise in the factory where the equipment FA is located can be suppressed, and the energy required to cool the factory's indoor temperature to the target temperature can be reduced. As a result, CO2 emissions can be reduced. The temperature of the top surface of the equipment FA's casing only needs to be at a temperature that promotes the regeneration of the desiccant material 90, and can be approximately 40°C to 100°C.

[0037] As shown in Figure 7, the housing 20 accommodates multiple trays 10. The side walls 50 are cylindrical and surround the trays 10. The roof 60 is positioned above the side walls 50. The roof 60 closes off the housing space 21 enclosed by the side walls 50.

[0038] In this embodiment, the first opening 51 and the second opening 52 are located in the side wall 50. The first opening 51 is located between the equipment FA and the side wall 50 in the vertical direction. Specifically, the first opening 51 is located below the lowest tray 10 in the vertical direction. The second opening 52 is located between the side wall 50 and the roof 60 in the vertical direction. Specifically, the second opening 52 is located above the uppermost tray 10 in the vertical direction. This makes it easier for heated air to pass through all of the trays 10, as will be described later.

[0039] The side wall 50 is detachable into a side wall body 70 and a side wall opening / closing section 80. Therefore, the side wall opening / closing section 80 can be removed from the side wall body 70, the tray 10 can be pulled out, and the desiccant material 90 can be viewed. The desiccant material 90 changes color depending on the moisture content, so the condition of the desiccant material 90 can be checked by looking at its color. A portion of the lower edge of the first side wall 71 is cut out. The gap formed between the central portion of the lower edge of the first side wall 71 in the Y direction and the equipment FA is the first opening 51. Similarly, a portion of the upper edge of the first side wall 71 is cut out. The gap formed between the central portion of the upper edge of the first side wall 71 and the roof 60 is the second opening 52. The second side wall 72 has the same shape as the first side wall 71. Therefore, as shown in Figure 8, the first opening 51 and the second opening 52 are formed in the first side wall 71 and the second side wall 72, respectively.

[0040] As shown in Figure 8, the waste heat recovery device 1 further includes a heat sink 30. The heat sink 30 is located at the bottom of the waste heat recovery device 1, more specifically at the bottom of the side wall 50. The heat sink 30 has a plurality of fins and releases heat transferred from the equipment FA into the housing space 21. Specifically, each of the plurality of fins has one end and the other end. Each fin is arranged such that the other end is located above the one end. In this embodiment, the heat sink 30 is fixed to the housing 20 via fastening members (not shown), but it does not have to be fixed.

[0041] The heatsink 30 is in contact with the equipment FA. Therefore, the heat emitted by the equipment FA is transferred to the heatsink 30. The heatsink 30 is located inside the enclosure 20. Therefore, the heatsink 30 emits heat into the enclosure space 21. The air below the enclosure space 21 is heated by the heat emitted by the heatsink 30. Because the temperature of the air below the enclosure space 21 is higher than the temperature of the air above, an upward airflow occurs. Therefore, the air pressure below the enclosure space 21 becomes lower. The air pressure above the enclosure space 21 becomes higher.

[0042] A first opening 51 is formed on the lower side of the housing 20. Therefore, outside air flows in from the first opening 51 towards the lower-pressure space within the housing space 21. A second opening 52 is formed on the upper side of the housing 20. Therefore, air from above the housing space 21 flows out from the second opening 52 towards the lower-pressure outside.

[0043] The desiccant material 90 placed in tray 10 uses the heat from the rising heated air to desorb the sorbed water.

[0044] As explained above, a cobalt chloride-coated polymer desiccant material 90 can be produced by preparing a cobalt chloride solution in which the concentration of cobalt chloride in the solvent is higher than 2000 ppm and lower than 10000 ppm, immersing the polymer desiccant material 90 in the prepared cobalt chloride solution for an immersion time of 5 minutes or more but no more than 60 minutes, and drying the separated polymer desiccant material 90. Since the color of this cobalt chloride-coated polymer desiccant material 90 changes between the dry and wet states, the amount of moisture adsorbed onto the cobalt chloride-coated polymer desiccant material 90 can be easily visually confirmed.

[0045] Furthermore, the polymer desiccant material 90 is colored with a coloring agent (cobalt chloride) relative to its original color (the color of the uncolored material). Based on the color interaction between the polymer desiccant material 90 as a base material and the coloring agent (cobalt chloride), the polymer desiccant material 90 has a color. The colored color changes between the dry and wet states, exhibiting a color difference. Since the color difference (ΔE*ab) is 14 or more, it can be recognized as a different color by humans. Considering the color state of the polymer desiccant material 90 as a base material, it becomes possible to visually confirm the state (amount of sorbed moisture) effectively. In this embodiment, the polymer desiccant material 90 with cobalt chloride has a color difference of 14 or more between the polymer desiccant material 90 with cobalt chloride in a predetermined wet state and the polymer desiccant material 90 with cobalt chloride in a predetermined dry state in the CIEL*a*b* color space. This allows for even better visual confirmation of the amount of moisture contained in the cobalt chloride-containing polymer desiccant material 90.

[0046] Furthermore, although the amount of cobalt chloride in the cobalt-coated polymer desiccant material 90 is trace and not considered harmful, it allows for good visual confirmation of the state of the polymer desiccant material 90 (amount of sorbed moisture). Incidentally, the cobalt chloride content in the cobalt-coated polymer desiccant material 90 of this embodiment is less than 0.1 wt%. In this way, because the content of cobalt chloride, which is an environmentally hazardous substance, is small, it is possible to provide a cobalt-coated polymer desiccant material 90 that has sufficiently reduced adverse effects on the environment, for example.

[0047] Furthermore, the waste heat recovery device 1 comprises a cobalt chloride-coated polymer desiccant material 90, a tray 10, a side wall 50, and a first opening 51. External air flows in from the first opening 51 towards the lower-pressure space of the housing space 21 and out from the second opening 52 towards the lower-pressure outside. The heated, rising air generated inside the housing 20 causes the cobalt chloride-coated polymer desiccant material 90 to detach water molecules. In the process of detaching water, it absorbs heat from the surroundings. Therefore, the waste heat recovery device 1 also functions as a heat removal device. Since the cobalt chloride-coated polymer desiccant material 90 changes color depending on whether it is dry or wet, the amount of moisture adsorbed on the cobalt chloride-coated polymer desiccant material 90 can be easily visually confirmed.

[0048] D. Other embodiments: (D1) The waste heat recovery device 1 in the above embodiment is equipped with a roof 60. In other embodiments, the waste heat recovery device 1 does not need to be equipped with a roof 60. In this case, the waste heat recovery device 1 does not need to be equipped with a second opening 52. In this form of waste heat recovery device 1, air flows into the housing 20 from the first opening 51 and flows out from the top of the open housing 20. Therefore, even in this form, an upward airflow can be generated inside the housing 20.

[0049] (D2) In the above embodiment of the waste heat recovery device 1, a heat sink 30 is provided inside the housing 20. In other embodiments, the waste heat recovery device 1 does not need to be provided with a heat sink 30. In other embodiments, the waste heat recovery device 1 may be provided with a fan 35 that generates an upward airflow inside the housing 20. Furthermore, the waste heat recovery device 1 may be provided with a solar panel that generates power to drive the fan 35.

[0050] (D3) In the waste heat recovery device 1 of the above embodiment, the color of the cobalt chloride-containing polymer desiccant material 90 can be seen by pulling out the tray 10. In another embodiment, at least a part of the side wall opening / closing section 80 may be made of a transparent material. In this embodiment, the color of the cobalt chloride-containing polymer desiccant material 90 can be seen from outside the transparent material through the transparent material without removing the side wall opening / closing section 80. Also, in the waste heat recovery device 1 of the above embodiment, all of the polymer desiccant material 90 arranged in the tray 10 is cobalt chloride-containing polymer desiccant material 90. In another embodiment, some of the desiccant material 90 arranged in the tray 10 may be cobalt chloride-containing polymer desiccant material 90, and the rest may be polymer desiccant material 90 without cobalt chloride. In this case as well, the moisture content can be checked by looking at the color of the cobalt chloride-containing polymer desiccant material 90.

[0051] (D4) With the above-mentioned cobalt chloride polymer desiccant material 90, the amount of moisture adsorbed on the cobalt chloride polymer desiccant material 90 can be confirmed by the color it exhibits. In addition, since the color exhibited by the cobalt chloride polymer desiccant material 90 fades and becomes lighter, the lifespan of the cobalt chloride polymer desiccant material 90 can be confirmed by its color. Therefore, it can also be used to confirm the replacement time of the cobalt chloride polymer desiccant material 90 used in the waste heat recovery device 1.

[0052] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features of the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of Symbols]

[0053] 1...Waste heat recovery device, 10...Tray, 11...Tray frame, 12...Tray bottom, 20...Housing, 21...Housing space, 30...Heat sink, 40...Support part, 50...Side wall, 51...First opening, 52...Second opening, 60...Roof, 70...Side wall main body, 71...First side wall, 72...Second side wall, 80...Side wall opening / closing part, 90...Polymer desiccant material, Cobalt chloride-containing polymer desiccant material, FA...Equipment

Claims

1. A polymer desiccant material, A polymer desiccant material is prepared by immersing a polymer desiccant material in a cobalt chloride solution with a cobalt chloride concentration of 2,000 ppm to 10,000 ppm for an immersion time of 5 minutes to 60 minutes, thereby depositing cobalt chloride.

2. A polymer desiccant material according to claim 1, The solvent of the cobalt chloride solution is a polymer desiccant material comprising at least one selected from the group consisting of (a) a monohydric alcohol having 2 or more carbon atoms, (b) a ketone, (c) a cyclic ether, and (d) a carboxylic acid other than formic acid and oleic acid.

3. The polymer desiccant material according to claim 2, The solvent is a polymer desiccant material comprising at least one selected from the group consisting of (a) ethanol, propanol, butanol, and 1-octanol, (b) cyclohexanone and acetone, (c) tetrahydrofuran, and (d) acetic acid.

4. A polymer desiccant material according to claim 1, The solvent in the aforementioned cobalt chloride solution is ethanol, and the material is a polymer desiccant.

5. A polymer desiccant material according to claim 1, The concentration of the cobalt chloride solution is 4000 ppm. A polymer desiccant material in which the immersion time is 10 minutes or more and 60 minutes or less.

6. A waste heat recovery device that is placed above a heat-releasing facility, The polymer desiccant material according to claim 1, A mesh-like tray on which the polymer desiccant material is arranged, A cylindrical side wall surrounding at least one of the trays, A waste heat recovery device comprising an opening positioned between at least one tray and the equipment.

7. A method for producing a polymer desiccant material with cobalt chloride, Prepare a cobalt chloride solution with a cobalt chloride concentration of 2000 ppm or more and 10000 ppm or less. The polymer desiccant material is immersed in the aforementioned cobalt chloride solution for an immersion time of 5 minutes to 60 minutes. A method for manufacturing the polymer desiccant material, comprising drying the polymer desiccant material.

8. A polymer desiccant material containing cobalt chloride, A polymer desiccant material containing cobalt chloride, having a color difference of 14 or more in the CIEL*a*b* color space between a wet state and a dry state.

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