Engineering and Applied Science Research (Nov 2023)
Performance and sustainability evaluation of rice husk-powered dryer under natural and forced convection mode
Abstract
Sun drying method has been used for drying agricultural commodities for centuries worldwide. The sun drying can be performed either by direct drying of the product under sunlight or drying using a solar collector-based dryer. However, a problem arises during the rainy season when there are lack of sunlight for proper drying. The application of biomass waste-powered dryers is a potential sustainable technology to encounter the problem. The present work aims to evaluate the performance and sustainability indicator of the rice husk-powered dryer under natural and forced convection modes while drying chili. The performance of the dryer evaluated is energy and exergy efficiency, and specific energy consumption (SEC). Meanwhile, the sustainability indicators evaluated are the waste-to-energy ratio (WER) and sustainability index (SI). The results show the performance and the sustainability indicator of the dryer are better under forced convection mode than that under natural convection mode. Overall energy and exergy efficiencies of the dryer are 3.58% and 4.93% under natural convection mode and the values are 16.85% and 16.13%, under force convection mode. Whereas, the SEC of the dryer is 26602.91 kg of rice husk/kg of water vapour for natural convection mode and 6979.89423 kg of rice husk/kg of water vapour under force convection mode. Furthermore, the sustainability of the dryer is better under force convection than under natural convection mode. WER under forced convection mode is lower than WER under natural convection mode. This gives a higher sustainability index (SI) of the dryer when operated under forced convection. The SI of the dryer ranges from 1.42 under natural convection to 1.92 under forced convection mode.
