A Method and system for solar air drying in agricultural and industrial processing

Abstract

A solar air-drying system for agricultural and industrial processing, comprising a solar absorber (6) with a V-corrugated pattern, coated with primer and heat-resistant black paint to maximize solar heat absorption; a transparent cover (8, 9) comprising double glazing to allow solar radiation to enter while preventing heat loss, thereby creating a greenhouse effect; a frame structure (3) made of mild steel (MS) sections and aluminum L-angles (12) to support the absorber and cover, facilitating the installation of the system on south-facing rooftops for optimal solar exposure; an insulation layer (2) positioned below the absorber to minimize heat loss and maintain the system's high energy efficiency; an air baffle (5) to direct airflow over the absorber, ensuring uniform heat distribution; anda centrifugal blower connected to insulated metal ducts to circulate heated air into a drying chamber.

Specification

Description:TECHNICAL FIELD

Embodiments disclosed herein relate to solar thermal system, and more particularly in a solar air drying used in agricultural and industrial processing. Pertains to solar air-drying system designed to be implemented in agricultural and industrial environments for drying and improving energy efficiency and environmental sustainability.

BACKGROUND OF THE INVENTION

India is an agriculturally dominant economy, with a significant portion of its population engaged in farming and related activities. Drying is a crucial post-harvest operation in agriculture, but the widely adopted traditional open sun drying method has led to deterioration in product quality and significant post-harvest losses.There requires an effective post-harvest processing to enhance the shelf life and quality of various agricultural products.Cash crops such as tea, coffee, cardamom, and spices have gradually transitioned from open sun drying to more conventional fossil fuel-driven drying systems to improve product quality and processing efficiency. A prime example is the processing of pulses, the staple food second only to rice and wheat in India, which is increasingly moving from open sun drying to fossil fuel-based systems such as oil or firewood.

Apart from agriculture, a large part of the country's workforce is employed in industrial activities, in which drying is an essential operation. Industrial drying consumes a vast amount of fossil fuels, including oil, coal, firewood, and, in some cases, electrical heating coils. While many industrial processes require hot air at low temperatures (60-80°C), others demand higher temperatures above 90°C. The current reliance on fossil fuels for these heating systems has resulted in high energy consumption and significant environmental pollution.
India, stretching from 8 to 36-degree north latitude and from 6 to 95-degree east longitude, has a good potential of solar energy availability throughout the year in almost all parts of the country.

With an average of 250-300 days of sunshine and a mean daily global radiation of 5.4 to 5.8 kWh/m² per day, solar energy presents a highly viable alternative to conventional energy sources.Vast landscape and geographical location of India offer a good potential for the utilization of solar energy to ease the stress over conventional fuels. Realizing the importance of Solar Energy for process requirement both in agriculture and industries, many attempts were made in India. Several food products were dried using solar heat in small level driers, however, industries which are in need of large output were left without choice.However, despite numerous attempts to utilize solar energy for drying in small-scale applications, industries requiring large-scale output have had limited options for implementing solar technology.

Hence, the traditional open sun drying methods and fossil fuel-based drying systems leads to inefficient energy utilization, environmental pollution, and compromised product quality. Current solar drying systems predominantly utilize copper absorbers, which are expensive and less efficient for industrial applications requiring high temperatures.

Recognizingthe need for a cleaner and more sustainable solution, solar heating systems, such as solar water and air heaters, offer significant potential for reducing fossil fuel consumption in agriculture and industry. The Solar Air-Drying System (SADS) aims to address the need for large-scale, efficient, and environmentally friendly drying systems. It can be applied to agricultural products such as fruits, vegetables, spices, and other cash crops, as well as industrial applications, providing a sustainable alternative to fossil fuels.Therefore, solar air drying system using a special V-corrugated aluminium absorber, offering a cost-effective, efficient, and cleaner alternative for drying applications.
Hence, there is a need in the art for solutions which will overcome the above-mentioned drawback(s), among others.

OBJECTS OF THE INVENTION

The primary object of the embodiment herein is to disclose methods and systems for configuring a solar air-drying system with V-corrugated aluminum absorber.

Another object of the embodiments herein is to disclose methods and systems for offering higher efficiency, greater cost-effectiveness, and the ability to achieve higher operating temperatures.

Another object of the embodiments herein is to disclose methods and systems for providingthe solar air-drying system capable of achieving temperatures above 80°C, making it suitable for a wide range of industrial and agricultural drying processes. Further object of the embodiments herein is to disclose methods and systems forproviding a cost-effective system to reduce or eliminate the use of fossil fuels in drying processes, thereby offering both economic and environmental benefits.

Further object of the embodiments herein is to disclose methods and systems for facilitating the seamless transition from fossil fuel-based to solar-based drying processes in various industries.

Another object of the embodiments herein is to disclose methods and systems for improving the quality of dried products, by providing more consistent and controllable drying conditions.

Another object of the embodiments herein is to disclose methods and systems to increase energy security and reduce the operational costs for industries and agricultural operations that rely heavily on drying processes.
A further object of the embodiments herein is to disclose methods and systems to achieve durability, by configuring the system for long-term use with a lifespan of 15 to 20 years.

SUMMARY OF THE INVENTION

These and other aspects of the embodiments herein will be betterappreciated and understood when considered in conjunction with the followingdescription and the accompanying drawings. It should be understood, however,that the following descriptions, while indicating at least one embodiment andnumerous specific details thereof, are given by way of illustration and not oflimitation. Many changes and modifications may be made within the scope of theembodiments herein without departing from the spirit thereof, and theembodiments herein include all such modifications.

The Solar Air Drying System utilizes a novel V-corrugated aluminium absorber to enhance the efficiency of solar thermal energy capture and conversion compared to conventional copper absorbers. This system is designed to retrofit existing industrial and agricultural drying processes, reducing reliance on fossil fuels and minimizing environmental impact. The SADS can cater to high-temperature processes requiring hot air above 80°C with a partial energy delivery (PED) system and low-temperature processes below 80°C with a full energy delivery (FED) system. The materials used are locally available, offering simple maintenance and long-term reliability. The system's payback period is generally less than three years, making it economically viable.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the variousfigures. The embodiments herein will be better understood from the followingdescription with reference to the following illustratory drawings. Embodimentsherein are illustrated by way of examples in the accompanying drawings, and inwhich:

FIG. 1 is an example diagram illustrating a schematic view of a solar air-dryingsystem (SADS) installed on the roof of an agricultural-industrial building, along with an Ethylene Propylene Diene Monomer (EPDM)rubber holding the top glazing toughened glass along with aluminium y-section, according to embodiments as disclosed herein; and

FIG. 2 is an example diagram illustrating an exploded view of the V-corrugated blackened absorber, according to embodiments as disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention as hereinbefore described with reference to the accompanying drawings.

Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

As used herein, the singular forms "a", "an", "the" include plural referents unless the context clearly dictates otherwise. Further, the terms "like", "as such", "for example", "including" are meant to introduce examples which further clarify more general subject matter, and should be contemplated for the persons skilled in the art to understand the subject matter.

In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term "about." Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Embodiments herein disclose methods and systems for configuring asolar air-dryingmechanism used in agricultural and industrial processing. Referring now to the drawings, and more particularly to FIGs.1 through 2, where similar reference characters denote corresponding features consistently throughout the figures, there are shown at least one embodiment.

Embodiments herein disclose methods and systems for configuring asolar air-drying mechanism used in agricultural and industrial processing. Embodiments as disclosed herein comprising a V-corrugated blackened absorber mounted on the roof, the transparent tempered glass cover, and a insulated ducts that carry the heated air to the drying chamber. Embodiments herein comprises a metal frame structure supporting a collector and the path of airflow through the absorber.

As illustrated in FIG. 1, the solar air-drying mechanism comprises a collector outer sheet cover 1, a side and bottom insulation 2, a frame 3, a galvanised (GI) cladding sheet 4, an air baffle 5, a solar absorber 6, a partition sheet 7, a double glazing 8, a top glazing 9, an aluminium y-section 10, an Ethylene Propylene Diene Monomer (EPDM) rubber, and an aluminum L-angle.

As illustrated in FIG. 2, the absorber (6) comprises a special V-corrugated blackened aluminum surface, which is well insulated on the lower side,which is configured to increase the surface area for absorption, thereby enhancing the system's efficiency. To maximize heat absorption, the absorber is coated with primer and heat-resistant black paint. This coating ensures durability while enhancing the thermal performance of the absorber.

For an instance, the absorber is constructed from 24 Standard Wire Guage (SWG) aluminum featuring a unique V-corrugated pattern, which significantly increases the surface area for heat absorption. The increased surface area results in a higher efficiency of solar energy capture. The absorber is coated with a metal primer and finished with boiler-grade black paint to ensure maximum heat absorption and protection against environmental elements. To minimize heat loss, the absorber (6) is insulated on its lower side (2). This insulation is essential in maintaining the system's high energy efficiency. The absorber is covered by a transparent material (8, 9) that allows solar radiation to enter while preventing heat from escaping, thereby creating a greenhouse effect that further boosts the efficiency of the system.

System Assembly & Installation
The solar heating system is assembled and installed on the south-facing roofs of agro-industrial houses to maximize sunlight exposure. The assembly begins with the installation of the metal frames (3) on the rooftop. These frames support the entire collector assembly. Insulation materials (2) are placed within the frame to minimize heat losses. The special V-corrugated aluminum absorber (6) is installed within the frame, and the system is enclosed with an outer sheet cover (1) to provide structural integrity and protection against external factors.

A 4 mm tempered glass cover (8, 9) is placed over the absorber to protect it from environmental elements while allowing maximum solar radiation to pass through. This cover consists of double glazing (8) and top glazing (9) to ensure optimum thermal insulation and durability. The glass cover is supported by an aluminum Y-section (10) and EPDM rubber (11) to ensure a tight seal and prevent heat loss. The tempered glass is further supported by aluminum L-angles (12) and mild steel (MS) sections (3) to maintain the structure's integrity and provide the necessary vertical air space between the absorber and the roof.

The airflow space is a critical component of the system. A vertical space is maintained between the cover and the roof to facilitate airflow, ensuring efficient heat transfer. This vertical air gap allows for the convection currents that are essential for maintaining a uniform temperature within the collector. The system's enclosure (1) is completed with GI cladding sheets (4) and partition sheets (7) to direct airflow and minimize heat loss. An air baffle (5) is included to guide the airflow effectively over the absorber, ensuring that the heated air is uniformly distributed before being directed to the drying chamber.

Operation
During daylight hours, the solar absorber (6) collects sunlight and transfers the absorbed heat to the air flowing over or below it. The collector, supported by metal frames and sections (3), is strategically installed on south-facing rooftops for maximum solar exposure. The heated air is collected and then directed through a network of insulated ducts. A centrifugal blower is connected to hot air outlets through insulated metal ducts to circulate the heated air into the drying chamber or further heating systems. The blower ensures continuous circulation of hot air, which is critical for maintaining uniform drying conditions.

For low-temperature applications (60°C-80°C), the system operates in Full Energy Delivery (FED) mode, where the air is heated solely by the solar absorber (6). The heated air is then directed to the drying chamber through insulated metal ducts. For high-temperature applications (above 80°C), the system operates in Partial Energy Delivery (PED) mode. In this mode, the air is preheated by the solar absorber and further heated by a conventional furnace to achieve the desired temperature. The system is designed to ensure efficient heat exchange and consistent performance, providing the necessary thermal environment for the drying process.

Implementation
The implementation of the SADS involves several key steps to ensure its effectiveness and efficiency:
1. Developing a Large-Scale System: Utilizing existing rooftops of agro-industrial houses as solar collectors to ensure reliability and longer life. The system is designed to integrate seamlessly with existing infrastructure, using metal frames (3) and collector outer sheet covers (1) for support and protection.
2. Cost-Effective Retrofitting: Providing a cost-effective solar air-drying system that can be easily retrofitted into existing environments. The use of local materials, such as aluminum Y-sections (10) and L-angles (12), ensures that the system is economically viable while offering optimum efficiency.
3. Non-Fossil Fuel Methodology: Offering a low-cost, non-fossil fuel method for processing large quantities of agricultural and industrial products. The use of solar heating reduces the dependency on fossil fuels, making the system particularly beneficial for developing countries with high solar capacity.
4. Hygienic Processing: Ensuring hygienic processing of food products, such as salted and dried fish, using solar heating. The sealed enclosure with double glazing (8) and top glazing (9) ensures that the processing environment is clean and free from contaminants, resulting in high-quality end products.

By incorporating these design and operational features, the SADS provides a sustainable, efficient, and eco-friendly solution for agro-industrial drying processes. The reference numerals highlight the key components of the system, illustrating its innovative approach to harnessing solar energy for practical applications.
, Claims:1. A solar air-drying system for agricultural and industrial processing, comprising:

a solar absorber (6) with a V-corrugated pattern, coated with primer and heat-resistant black paint to maximize solar heat absorption;
a transparent cover (8, 9) comprising double glazing to allow solar radiation to enter while preventing heat loss, thereby creating a greenhouse effect;
a frame structure (3) made of mild steel (MS) sections and aluminum L-angles (12) to support the absorber and cover, facilitating the installation of the system on south-facing rooftops for optimal solar exposure;
an insulation layer (2) positioned below the absorber to minimize heat loss and maintain the system's high energy efficiency;
an air baffle (5) to direct airflow over the absorber, ensuring uniform heat distribution; and
a centrifugal blower connected to insulated metal ducts to circulate heated air into a drying chamber, maintaining consistent drying conditions.

2. The system as claimed in claim 1, wherein the transparent cover (8, 9) comprises a tempered glass cover, supported by an aluminum Y-section and EPDM rubber.

3. The system as claimed in claim 1, wherein the frame structure (3)comprises a vertical air space between the transparent cover (8, 9) and the roof to facilitate airflow.

4. The system as claimed in claim 1, wherein the centrifugal blower circulates the heated air through the drying chamber to maintain uniform drying conditions for the agricultural or industrial products being processed.

5. A method for operating a solar air drying system, comprising installing the solar heating system on the south-facing roof of an agro-industrial house; allowing solar radiation to pass through the transparent cover to the V-corrugated aluminum absorber; collecting and transferring heat to the air flowing over or below the absorber; directing the heated air to a drying chamber through insulated metal ducts connected to a centrifugal blower; operating the system in Full Energy Delivery (FED) mode for low-temperature applications (60°C-80°C), where air is heated solely by the solar absorber; and operating the system in Partial Energy Delivery (PED) mode for high-temperature applications (above 80°C), where the air is preheated by the solar absorber and further heated by a conventional furnace.

6. The method as claimed in claim 5, wherein the V-corrugated pattern of the absorber increases the efficiency of heat absorption by expanding the surface area exposed to solar radiation.

7. The method as claimed in claim 5, wherein the transparent cover creates a greenhouse effect by allowing solar radiation to enter while preventing heat from escaping, thereby enhancing the thermal efficiency of the system.

8. The method as claimed in claim 5, wherein the heated air is circulated continuously by the centrifugal blower to maintain uniform drying conditions, improving the quality of the dried agricultural or industrial products.

9. The method as claimed in claim 5 for retrofitting existing agro-industrial drying systems, comprising providing the solar air drying system to replace or supplement existing fossil fuel-based drying systems; utilizing the existing rooftops of agro-industrial houses as solar collectors to support the installation of the system; integrating the solar absorber, transparent cover, frame structure, and airflow management components with the existing drying infrastructure; and ensuring hygienic processing of food products by using solar heating in a sealed enclosure, reducing reliance on fossil fuels and improving processing efficiency.

10. The method as claimed in claim 5, wherein the retrofitted SADS operates in either Full Energy Delivery (FED) or Partial Energy Delivery (PED) mode based on the temperature requirements of the drying process.

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