Experimental investigation of solar biomass hybrid dryer for drying large cardamom in the north‐eastern <scp>Himalayan</scp> state <scp>Sikkim</scp>

Abstract Sikkim, a state in northeastern India, is a leading producer of large cardamom ( Amomum subulatum Roxburgh ). A solar biomass hybrid (SBH) dryer with a drying capacity of 20 kg per batch was developed. In the absence of sunshine, the biomass gasifier acts as a backup supply of heat energy. Within 20 h, the moisture level could be lowered from an initial 82.3% moisture content to a final 10% moisture content by maintaining the drying temperature between 50 and 70°C. The air velocity during drying was maintained at approximately 0.70 m/s. The experimental results showed that the SBH dryer's drying efficiency was 35.84%, with a drying rate varying between 0.4 and 0.6 kg/h. The biomass gasifier consumed about 0.5 kg of biomass for every kg of dried material. A net reduction in drying time of about 80.76% and 33.39% respectively, was observed when compared to open sun drying and conventional furnace ( Bhatti) . The solar‐dried and open sun‐dried samples had an oil concentration of 2.91% and 3.08% respectively, while the Bhatti dried sample had the lowest at 1.5%. The SBH dryer exhibited the lowest extraneous matter (2.13%) compared to the open sun‐dried sample (3.78%) and traditional Bhatti (2.22%). The SBH dryer exhibited a minimal color change of 2.06, in contrast to the furnace ( Bhatti) dried samples at 6.21 and the open‐dried samples at 2.63. The developed SBH dryer was found to be suitable for northeast hilly regions, providing uninterrupted drying for small‐scale farmers in rural areas.