Experimental studies on drying of Zingiber officinale, Curcuma longa l. and Tinospora cordifolia in solar-biomass hybrid drier

An integral type natural convection solar drier has been fabricated and coupled with a biomass stove. Experiments have been conducted to test the performance of the drier by drying of Zingiber officinale (ginger), Curcuma longa l. (turmeric) and Tinospora cordifolia (guduchi) during the summer climate in Delhi. It was found that, during the load test for ginger, 18 kg of fresh product with an initial moisture content of 319.74(db)% was dried to a final moisture content of 11.8(db)% within 33 h. Similarly, moisture content of turmeric and guduchi were reduced from 358.96 to 8.8 and 257.45 to 9.67(db)% during 36 and 48 h of drying, respectively. The drying of these products has also been studied under ‘solar-only’ and open sun in the same climatic conditions and the results indicate that for all the products, drying is faster, and is within 33–48 h in hybrid drier, against 72–120 h in ‘solar-only’ operation of the same drier and 192–288 h in open sun. Efficiency of the drier during its two mode (solar and biomass separately) of operation has been estimated and quality evaluation of under-studied products showed that developed drier is suitable for the drying of these products. The developed drier is a simple system, which can be manufactured locally and can be used for drying of other agricultural products.