PH12017000232A1 - Drying method and apparatus using dehumidified and solar preheated air - Google Patents
Drying method and apparatus using dehumidified and solar preheated air Download PDFInfo
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- PH12017000232A1 PH12017000232A1 PH12017000232A PH12017000232A PH12017000232A1 PH 12017000232 A1 PH12017000232 A1 PH 12017000232A1 PH 12017000232 A PH12017000232 A PH 12017000232A PH 12017000232 A PH12017000232 A PH 12017000232A PH 12017000232 A1 PH12017000232 A1 PH 12017000232A1
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- Prior art keywords
- drying
- drying chamber
- solar
- air
- drying apparatus
- Prior art date
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- 238000001035 drying Methods 0.000 title claims abstract description 118
- 239000003570 air Substances 0.000 claims abstract description 110
- 239000002274 desiccant Substances 0.000 claims abstract description 26
- 239000012080 ambient air Substances 0.000 claims abstract description 7
- 230000002745 absorbent Effects 0.000 claims description 16
- 239000002250 absorbent Substances 0.000 claims description 16
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 9
- 239000000741 silica gel Substances 0.000 claims description 9
- 229910002027 silica gel Inorganic materials 0.000 claims description 9
- 239000011324 bead Substances 0.000 claims description 8
- 239000004744 fabric Substances 0.000 claims description 8
- 125000006850 spacer group Chemical group 0.000 claims description 4
- 239000002023 wood Substances 0.000 claims description 4
- 235000013399 edible fruits Nutrition 0.000 claims description 3
- 235000013372 meat Nutrition 0.000 claims description 3
- 235000013311 vegetables Nutrition 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 4
- 239000006096 absorbing agent Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- 241000195493 Cryptophyta Species 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000001154 acute effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000002551 biofuel Substances 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 235000014633 carbohydrates Nutrition 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 238000003306 harvesting Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 150000002632 lipids Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002417 nutraceutical Substances 0.000 description 1
- 235000021436 nutraceutical agent Nutrition 0.000 description 1
- 230000000243 photosynthetic effect Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 238000012251 post-harvest treatment method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Landscapes
- Drying Of Solid Materials (AREA)
Abstract
A drying apparatus includes a drying chamber (5) for storing a to-be-dried article, a fan (9) for drawing moist air outwardly of the drying chamber (5), a solar air heater (3) with an outlet section (32) connected to the drying chamber (5) at an inlet port (51) of the drying chamber ( 5) , and a desiccant unit ( 2) connected to an inlet section (31) of the solar air heater (3). An ambient air stream passes in sequence through the desiccant unit ( 2) for moisture removal and then through the solar air heater (3) for preheating using solar energy prior to flowing into the drying chamber ( 5) . Also disclosed is a method for drying a to-be-dried article inside a drying chamber (5) using air that is dried through a desiccant unit (2) and then heated with solar heat energy prior to flowing into the drying chamber (5).
Description
removably the outlet section (32) of the solar air heater (3) to the bottom wall (53) of the drying chamber (5) in this embodiment, the present invention is not limited in this respect.
Referring to FIG. 2, the solar air heater (3) according to the exemplary embodiment includes a transparent upper part (33), which is a transparent panel in this embodiment, and a lower part (34), which has a generally U-shaped cross-section in this embodiment. The upper part (33) and the lower part (34) cooperate to confine an air passage (35). In this embodiment, the left and right edges of the upper part (33) are attached to the lower part (34) using a pair of angle bars (38) that are adhesively bonded to the upper part (33) and the lower part (34). The lower part (34) includes a rigid outer layer (340) made of wood, an adiabatic middle layer (341) made of a heat insulation material, and a black body inner layer (342), such as a sheet of metal (e.g. galvanized iron) which is painted in black. The solar air heater (3) further includes a heat absorbent member (36) inside the air passage (35).
Referring to FIG.2 and FIG.3, in this embodiment, the heat absorbent member (36) includes a core part (361) made of wood and shaped as a rectangular frame, and a fabric covering (362), preferably a black fabric, to enclose the core part (361). The heat absorbent member o . (36) further includes spacers (363), such as rubber stoppers, to provide a space between the heat absorbent member (36) and the lower part (34) of the solar air heater (3). The solar air heater (3) further includes fasteners (37) to fasten the heat absorbent member (36) to the lower part (34) of the solar air heater (3). The fasteners (37) can be configured to extend directly into the core part (361), or into the spacers (363).
The solar air heater (3) absorbs solar heat energy, which is used to elevate the dry bulb temperature of an air stream passing through the air passage (35).
Referring to FIG. 1 and FIG. 4, the desiccant unit (2) according to the exemplary embodiment includes an air permeable container (21) and silica gel beads (22) inside the air permeable container (21). Front and rear walls (210) of the air permeable container (21) are formed with perforations (211) to permit air flow through the air permeable container (21). The shape of the perforations (211) is not limited in this embodiment. The inner side of each of the front and rear walls (210) has a screen attached thereto to prevent the silica gel beads (22) from escaping out of the air permeable container (21).
Referring to FIG. 5A and FIG. 5B, in this embodiment, the inlet section (31) of the solar air heater (3) is formed with a slit. The air permeable container (21) is inserted removably into the inlet section (31) of the solar air heater (3) wvia the slit. Removable connection between the desiccant unit (2) and the solar air heater (3) permits replacement of the former when the silica gel beads (22) are spent.
FIG. 6 shows a flowchart of a drying method using the drying apparatus according to the invention. An ambient air stream enters the desiccant unit (2), and moisture in the ambient air stream is removed by the silica gel beads (22). This process leads to a reduction in the amount of moisture per mass of air. The dry air stream from the desiccant unit (2) then enters the solar air heater (3) via the inlet section (31) and is heated in the solar air heater (3) before flowing out of the solar air heater (3) through the outlet section (32) and into the inlet port (51) of the drying chamber (5).
Because the dry air stream has low moisture content, most of the heat energy accumulated in the solar air heater (3) is used to increase the temperature of the air. This leads to fast temperature increase and, consequently, faster flow into the drying chamber (5) through natural convection. With low moisture content and high dry bulb temperature, the dehumidified and solar preheated air stream is more efficient at absorbing moisture from the to-be-dried articles inside the drying chamber (5), leading to an increased rate of drying. As the preheated air stream enters the drying chamber (5) through the inlet port (51), the air diffuser (6) at the inlet port (51) distributes the preheated air evenly in the drying chamber (5). The distributed air from the air diffuser (6) rises in the drying chamber (5) and absorbs moisture from the to-be-dried articles. To avoid recirculation of moist air inside the drying chamber (5), which may lead to a relatively inferior drying performance, the fan (9) draws moist air outwardly of the drying chamber (5).
When operated, the fan (9) can also prevent ambient moist air from directly entering the drying chamber (5) without passing through the desiccant unit (2) and the solar air heater (3).
The drying method is suitable for drying a variety of articles, including algae, fruits, vegetables, and meat.
While the invention has been described in connection with what 1s considered the exemplary embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
LY te ’ 1
DRYING METHOD AND APPARATUS USING DEHUMIDIFIED AND
SOLAR PREHEATED AIR
The present invention relates to dryers. More particularly, the present invention relates to a drying apparatus for removing moisture using air that is dehumidified via a desiccant unit and preheated with solar energy prior to flowing into a drying chamber where a to-be-dried article is stored.
Drying is an important post-harvest treatment method for improving the shelf-life, durability, and quality of agricultural products. Conventional drying technologies, however, require substantial amounts of energy, making the drying process expensive. For example, the conventional drying technologies employed in the drying of microalgae can account for up to 40% of energy and product costs.
Microalgae are valuable agricultural products.
These simple, photosynthetic organisms are known sources of lipids, carbohydrates, proteins, pigments, and other chemical compounds which can be converted into a variety of high-value products suitable for use in food, nutraceuticals, pharmaceuticals, cosmetics, and other commercial products. They have also been
0 . identified as attractive sources of biofuel. While large-scale harvesting and processing of microalgae are important economic activities, they suffer fromthe high costs of the drying step. There is thus a need for a low-cost and energy-efficient apparatus suitable for drying agricultural products, particularly microalgae.
A conventional drying apparatus is described in U.S.
Patent Application Publication No. 20140182158 Al. A solar dryer disclosed therein includes a drying chamber with a wire mesh for placement of a material to be dried and a drying agent (e.g. silica gel) under the wire mesh, and a solar collector/absorber connected to the drying chamber. Solar energy is used to heat air passing through the solar collector/absorber, and fans are used to induce air convection through the collector/absorber and the drying chamber. A disadvantage of this design is that because the air is dehumidified after heating, heat energy in the solar collector/absorber is consumed in heating the mass of moisture in the air and the mass of air, which can have an adverse effect on drying efficiency.
Another drying apparatus is described in U.S. Patent
Application Publication No. 20120227279 Al. A drying system disclosed therein includes a desiccant wheel to dry incoming air. The dried air is heated using a heating element to promote drying of an article within the
; . drying system. A portion of the heated air is diverted toward the desiccant wheel.
According to an aspect of this invention, a drying apparatus comprises a drying chamber, a fan, a solar air heater, and a desiccant unit. A to-be-dried article is stored in the drying chamber. The fan serves to draw moist air outwardly of the drying chamber. An outlet section of the solar air heater is connected to the drying chamber at an inlet port of the drying chamber.
An inlet section of the solar air heater is connected to the desiccant unit. In operation, an ambient air stream passes in sequence through the desiccant unit for moisture removal and then through the solar air heater for preheating using solar energy prior to flowing into the drying chamber.
In one embodiment, at least one tray is disposed inside the drying chamber for placing the to-be-dried article thereon.
In one embodiment, the drying chamber has a door for placing the to-be-dried article inside the drying chamber.
In one embodiment, the fan is mounted to a top wall of the drying chamber.
In one embodiment, the inlet port of the drying chamber is provided at a bottom wall of the drying
A . chamber.
In one embodiment, an air diffuser is disposed at the inlet port of the drying chamber.
In one embodiment, the drying chamber has legs for standing on the ground, and the solar air heater is disposed to incline upwardly from the inlet section to the outlet section.
In one embodiment, the solar air heater includes a transparent upper part, and a lower part that cooperates with the upper part to confine an air passage.
The lower part includes a rigid outer layer, an adiabatic middle layer, and a black body inner layer.
The lower part has a generally U-shaped cross section, and a heat absorbent member is disposed inside the air passage.
In one embodiment, the heat absorbent member includes a core part made of wood, and a fabric covering to enclose the core part. The core part can have the shape of a rectangular frame, and the fabric covering can be a black fabric. The heat absorbent member further includes spacers to provide a space between the heat absorbent member and the lower part of the solar air heater.
In one embodiment, the solar air heater includes fasteners to fasten the heat absorbent member to the lower part of the solar air heater.
In one embodiment, the desiccant unit includes an
; . air permeable container and silica gel beads inside the air permeable container. The air permeable container may be mounted removably to the inlet of the solar air heater.
According to another aspect of this invention, a method for drying a to-be-dried article comprises: removing moisture from an ambient air stream using a desiccant unit to result in a dry air stream; preheating the dry air stream using solar energy to result in a preheated air stream; supplying the preheated air stream to a drying chamber that contains the to-be-dried article; and drawing moist air outwardly of the drying chamber.
In one embodiment, the desiccant unit includes silica gel beads.
The method of this invention may be employed to dry a variety of articles, including algae, fruits, vegetables, and meat.
Other features and advantages of the invention will become apparent in the following detailed description of the embodiment with reference to the accompanying drawings, of which:
FIG. 1 is a schematic side view of an embodiment of a drying apparatus according to the invention;
FIG. 2 is a schematic sectional view of a solar air heater of the disclosed embodiment;
FIG. 3 is a schematic top view of a heat absorbent member of the disclosed embodiment;
FIG. 4 is a schematic front/rear view of an air permeable container of a desiccant unit of the disclosed embodiment;
FIG. 5A and FIG. 5B are schematic top views illustrating removable connection between the desiccant unit and the inlet section of the solar air heater according to the disclosed embodiment; and
FIG. 6 is a flowchart of an embodiment of a drying method according to the invention.
FIG. 1 shows an exemplary embodiment of a drying apparatus according to the invention. The drying apparatus removes moisture from a to-be-dried article using air that is dehumidified and preheated prior to flowing into a drying chamber where the to-be-dried article is stored.
The drying apparatus comprises: a drying chamber (5) having an inlet port (51); a fan (9) for drawing moist air outwardly of the drying chamber (5); a solar air heater (3) having an inlet section (31) and an outlet section (32) connected to the drying chamber (5) at the inlet port (51); and a desiccant unit (2) connected to the inlet section (31) of the solar air heater (3). In
. : . this embodiment, one or more trays (7) are provided inside the drying chamber (5) for placing to-be-dried articles (not shown) thereon. The to-be-dried articles are placed inside the drying chamber (5) through a door (8) of the drying chamber (5). In this embodiment, the drying chamber (5) has a top wall (52), and the fan (9), i.e. an exhaust fan, is mounted to the top wall (52) of the drying chamber (5). The drying chamber (5) also has a bottom wall (53) provided with the inlet port (51).
In this embodiment, the drying chamber (5) has legs (54) for standing on the ground, and the solar air heater (3) is disposed to incline upwardly at an acute angle from the inlet section (31) to the outlet section (32) to allow the natural convective flow of heated air to enter the drying chamber (5). In some embodiments, the angle formed between the solar air heater (3) and the horizontal plane can vary to allow adaptability with the change in the angle of incidence of the sun as the day commences. In this embodiment, the inlet port (51) of the drying chamber (5) is strategically positioned at the middle location of the bottom wall (53) of the drying chamber (5). In this embodiment, an air diffuser (6) is disposed at the inlet port (51) of the drying chamber (5). This configuration allows a better distribution of the heated air inside the drying chamber (5) leading to a better drying performance.
While fasteners (not shown) are used to connect
Claims (19)
1. A drying apparatus comprising: a drying chamber (5) for storing a to-be-dried article, the drying chamber (5) having an inlet port (51): a fan (9) for drawing moist air outwardly of the drying chamber (5); a solar air heater (3) having an inlet section (31), and an outlet section (32) connected to the drying chamber (5) at the inlet port (51); and a desiccant unit (2) connected to the inlet section {31) of the solar air heater (3); - wherein an ambient air stream passes in sequence through the desiccant unit (2) for moisture removal and then through the solar air heater (3) for preheating using solar energy prior to flowing into the drying chamber (5).
; 2. The drying apparatus as claimed in claim 1, further comprising at least one tray (7) inside the drying chamber (5) for placing the to-be-dried article thereon.
3. The drying apparatus as claimed in claim 1, wherein the drying chamber (5) has a door (8) for placing the to-be-dried article inside the drying chamber (5).
4. The drying apparatus as claimed in claim 1, wherein the drying chamber (5) has a top wall (52), and the fan (9) is mounted to the top wall (52) of the drying chamber (5) .
5 .
5. The drying apparatus as claimed in claim 1, wherein the drying chamber (5) has a bottom wall (53) provided with the inlet port (51).
6. The drying apparatus as claimed in claim 5, further comprising an air diffuser (6) disposed at the inlet port (51).
7. The drying apparatus as claimed in claim 1, wherein the drying chamber (5) has legs (54) for standing on the ground, and the solar air heater (3) is disposed to incline upwardly from the inlet section (31) to the outlet section (32).
8. The drying apparatus as claimed in claim 1, wherein the solar air heater (3) includes: a transparent upper part (33); and a lower part (34) that cooperates with the upper part (33) to confine an air passage (35), the lower part (34) including a rigid outer layer (340), an adiabatic middle layer (341), and a black body inner layer (342).
9. The drying apparatus as claimed in claim 8, wherein the lower part (34) has a generally U-shaped cross section.
10. The drying apparatus as claimed in claim 8, wherein the solar air heater (3) further includes a heat absorbent member (36) inside the air passage (35).
11. The drying apparatus as claimed in claim 10, wherein the heat absorbent member (36) includes a core part (361) made of wood, and a fabric covering (362) to enclose the core part (361).
12. The drying apparatus as claimed in claim 11, wherein the core part (361) is shaped as a rectangular frame, and the fabric covering (362) is a black fabric.
13. The drying apparatus as claimed in claim 11, wherein the heat absorbent member (36) further includes spacers (363) to provide a space between the heat absorbent member (36) and the lower part (34) of the solar air heater (3).
14. The drying apparatus as claimed in claim 10, wherein the solar air heater (3) further includes fasteners (37) to fasten the heat absorbent member (36) to the lower part (34) of the solar air heater (3).
15. The drying apparatus as claimed in claim 1, wherein the desiccant unit (2) includes an air permeable container (21) and silica gel beads (22) inside the air permeable container (21).
16. The drying apparatus as claimed in claim 15, wherein the air permeable container (21) is mounted removably to the inlet section (31) of the solar air heater (3).
17. A drying method comprising: removing moisture from an ambient air stream using a desiccant unit (2) to result in a dry air stream; preheating the dry air stream using solar energy to result in a preheated air stream; supplying the preheated air stream to a drying chamber (5) that contains a to-be-dried article; and drawing moist air outwardly of the drying chamber
(5).
18. The drying method as claimed in claim 17, wherein the desiccant unit (2) includes silica gel beads (22).
19. The drying method as claimed in claim 17, wherein the to-be~dried article is selected fromalgae, fruits, vegetables, and meat.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PH12017000232A PH12017000232A1 (en) | 2017-08-15 | 2017-08-15 | Drying method and apparatus using dehumidified and solar preheated air |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PH12017000232A PH12017000232A1 (en) | 2017-08-15 | 2017-08-15 | Drying method and apparatus using dehumidified and solar preheated air |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| PH12017000232A1 true PH12017000232A1 (en) | 2019-03-04 |
Family
ID=65681268
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PH12017000232A PH12017000232A1 (en) | 2017-08-15 | 2017-08-15 | Drying method and apparatus using dehumidified and solar preheated air |
Country Status (1)
| Country | Link |
|---|---|
| PH (1) | PH12017000232A1 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120227279A1 (en) * | 2007-05-09 | 2012-09-13 | Protege Enterprises | Dryer having structure for enhanced drying efficiency and method of use |
| US20140182158A1 (en) * | 2011-05-16 | 2014-07-03 | Council Of Scientific And Industrial Research | Solar dryer with enhanced efficiency of drying |
-
2017
- 2017-08-15 PH PH12017000232A patent/PH12017000232A1/en unknown
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120227279A1 (en) * | 2007-05-09 | 2012-09-13 | Protege Enterprises | Dryer having structure for enhanced drying efficiency and method of use |
| US20140182158A1 (en) * | 2011-05-16 | 2014-07-03 | Council Of Scientific And Industrial Research | Solar dryer with enhanced efficiency of drying |
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