MUMBAI, India, July 7 -- Intellectual Property India has published a patent application (202641076897 A) filed by Vinodh S on June 22, 2026, for Passive Solar Dryer Incorporating Copper–aluminium Composite Absorbent Plate For Enhanced Thermal Drying Efficiency.
Inventors include Maria Therease Ramya W; Vinodh S; Clement M; Jessy L; Nandhini R; Karthika M; Sangeetha R; and Mohana Sudha K.
The application for the patent was published on July 03, 2026, under issue no. 27/2026.
Abstract: The present invention discloses a Passive Solar Dryer incorporating a Copper–Aluminium Composite Absorbent Plate for Enhanced Thermal Drying Efficiency, designed to provide hygienic, energy-efficient, and high-quality dehydration of medicinal herbs, agricultural produce, fruits, vegetables, spices, pharmaceutical raw materials, and biomass products entirely without electrical energy consumption. Conventional open sun drying methods suffer from contamination, nutrient degradation, non-uniform drying, and poor product quality. Electrical and fuel-based dryers, while offering controlled conditions, impose significant operational costs, fossil fuel dependency, and environmental concerns. Existing passive solar dryers with single-material absorber plates further exhibit poor thermal retention, limited heat transfer efficiency, temperature fluctuation, and non-uniform drying performance, reducing their effectiveness particularly for thermally sensitive products such as medicinal herbs. The present invention addresses these limitations through the incorporation of a copper–aluminium composite absorbent plate within a passive solar dryer configuration. The composite absorber plate leverages the high thermal conductivity of copper for rapid heat transfer and the lightweight, corrosion-resistant, and heat-spreading properties of aluminium to deliver superior solar radiation absorption, uniform temperature distribution, and improved heat retention within the drying chamber. The composite plate is coated with black heat-absorbing paint to maximize solar energy capture. The solar dryer comprises a solar heating chamber, drying chamber, transparent glazing cover, composite absorbent plate, natural air circulation vents, insulation layer, and multiple aluminium mesh drying trays. Solar radiation entering through the transparent glazing cover is absorbed by the black-coated composite plate and converted to thermal energy. The greenhouse heat trapping effect within the heating chamber elevates the enclosed air temperature, which rises naturally through passive convection into the drying chamber. Moisture-laden hot air exits through upper ventilation openings while cooler ambient air continuously enters through lower inlet vents, maintaining sustained airflow circulation without fans, blowers, or external power. The invention achieves significantly accelerated moisture removal rates, improved drying chamber temperatures, reduced total drying duration, and enhanced product quality compared to conventional open sun drying and standard passive solar dryers. The system provides effective protection against dust, insects, pests, rainwater, and environmental contaminants, ensuring hygienic drying conditions throughout the process. The preserved color, aroma, medicinal properties, and nutritional content of the dried products confirm the suitability of the invention for pharmaceutical raw material processing and herbal medicine preparation. The passive solar dryer is fabricated using locally available and economical materials including galvanized iron sheets, mild steel structural components, aluminium mesh trays, and standard glazing materials, rendering the system cost-effective and deployable in rural and off-grid environments without infrastructure requirements. The scalable modular architecture supports deployment in agricultural drying, herbal processing industries, rural food preservation, pharmaceutical drying, post-harvest management, and sustainable farming applications worldwide. In summary, the present invention represents a significant advancement in passive solar thermal drying technology, delivering improved energy efficiency, hygienic product quality, and sustainable agricultural processing through the novel integration of a copper–aluminium composite absorbent plate within a passive solar dryer system.
Disclaimer: Curated by HT Syndication.
