Heated air and seed cotton move through the shelves of drier air temperature drops and the heat lost is used to increase the temperature of cotton vaporizing the moisture in cotton and resultant drying.

Efficiency of heat transfer decreases with decrease of air temperature and heating of seed cotton and thus lowering of differential temperature.

System suffers from poor overall thermal efficiency.

Part of heated air is used to heat the shelves & counter-flow arrangement of cotton travel and shelf heating air travel makes up the heat lost by air moving in contact with seed-cotton, thus significantly improving the differential temperature condition through out the process of drying within the tower drier.

Air used for heating of shelves is remixed and recirculated with the drying and conveying hot air, thus utilizing its residual heat also.

Overall thermal efficiency of the system is more the double compared to conventional design of tower drier.