(Development of Rotary Rack Type Greenhouse Effect (GHE) Hybrid Solar Dryer to Achieve the Airflow Uniformity)

Abstract

A study on design and testing performance of hybrid greenhouse effect (GHE) solar dryer with rotating rack was conducted. The objectives of this research were to obtain the optimum design of green house effect (GHE) hybrid solar dryer using rotary rack for uniformity of heat flow. The first year of the research results the design of hybrid solar dryer of vertical rotary rack which based on the temperature simulation and CFD simulation. The optimal design of hybrid solar dryer has the dimension of 1.100 m x 0.865 m x 1.350 m. The range of drying room temperature is 41.3°C to 48.1°C and relative humidity of 32.1 % to 44.1 %. Under this condition, 10 kg local cardamom (Amomum cardamomum Wild) can be dried for 30 to 40 hours, at initial moisture content 80-82 % wb until final moisture content of 9-10 % wb. Racks are shift 45° every hours and continue rotation of racks is carried out for 10 minutes at the initial drying and 10 minutes every hour. Uniformity of the final moisture content was achieved that proved by standard deviation of moisture content of 1.1 %. Furthermore, the second year of the research results the scale up design of hybrid solar dryer of vertical rotary rack that had the dimension of 2.15 m x 1.75 m x 1.9 m. Dryer capasity is 96 kg of local cardamom. Heat energy from solar and biomass combustion. Racks is rotated by human power. The experiment shows that the drying room temperature is 48.5°C and relative humidity of 46 %. Drying time required is 44 hours. Combustion rate of biomass is 1.3 kg of firewood/hours. Input energy is 18.2 MJ/kg vapor evaporated by the product and total efficiency is 18.6 %. Based on the economical analysis of dryer results that the drying project is visible to be implementation.