Development and Evaluation of Mobile Two-way Reversible Air Flow Flat-bed Paddy Dryer

A mobile two-way air flow flat-bed paddy dryer of 3-tonne capacity was developed and evaluated. With the provision of a two-way air flow arrangement for reversal of air direction, drying was uniform along the grain bed depth of 500 mm without the need to mix the grain during drying. The moisture content differential among different layers at 200 mm spacing was 3.1% and 0.80% for one-way upward and two-way reversible air flow mode, respectively. Specific energy consumption was 4.86 MJ.kg-1 and 4.34 MJ.kg-1, whereas the drying efficiency was 49.4% and 55.3% for conventional onedirectional and bi-directional reversible air flow mode, respectively. Head rice yield was 4.4% more for paddy dried in two-way reversible air flow mode as compared to conventional one-direction upward air flow drying. The cost of drying was less in twoway (reversible) air flow mode (` 9.80 per kg water) as compared to one-direction air flow mode ( ₹ 11.06 per kg water).