Browsing by Author "Brenndorfer, B."

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    Development of a three stage solar drying system for coffee
    (1986) Trim, D.S.; Brenndorfer, B.
    The traditional practice of sun drying arabica coffee on tables is proving inadequate during the peak processing periods in some cooperative factories in Kenya. A three year programme to develop a solar drying system capable of maintaining a daily throughput of 3t of dried parchment coffee is described. The system consists of three separate stages; initial skin drying, intermediate sun drying on tables - mandatory for Kenyan coffee - and final drying. The skin trying and final drying stages take place in a purpose-designed building which incorporates a solar collector within the roof. Power is provided by a diesel-driven engine directly coupled to an axial-flow fan capable of maintaining an air flow of 8 m's-1. Waste heat from the engine is used to heat the air thereby enabling drying to proceed in all but the worst weather and at night. The solar collector performed well within design specification with a collection efficiency of nearly 50%. In routine operating conditions system-dried coffee equalled that of control batches dried by the traditional method under ideal conditions.