Leopold Oscar Nelwan

RECENT DEVELOPMENT OF GHE SOLAR DRYING IN INDONESIA

Prototypes of greenhouse effect GHE solar dryer have been tested and their technical performances for drying of tropical products have been obtained. Quality of the dried products was comparable to the existing standard used in estate plantation. The latest drying experiment with fermented cocoa beans using mechanical stirrer, and with a stationary rectangular bin for coffee berries, showed that the developed drying system was capable of reducing the total specific energy to 6.2 MJ/kg and 5.2 MJ/kg water evaporated, respectively. Therefore, the results of the study suggest that the current design could now be used in helping the farmers and fishermen to produce better quality products.

Study of temperature characterization of agricultural waste in the development of stove for combine heat power

Indonesia is one of tropical country in the world, therefore biomass product can find a lot in Indonesia. In the other side, waste of agricultural product is one of biomass resources which is can be converting to energy using Combine Heat Power for the example. In this paper, will be discussed about the temperature characterization due to influence of feeding rate and air flow rate. The contribution of this paper will show the temperature achievement of flue gas as the result of direct combustion in a stove. The research conducted using coconut shell as raw fuel material with varying feed rate and air flow rate. In this research also use the excess air to know the effect. The result show that the temperature of flue gas in direct combustion of coconut shell can reach of 520°C and temperature at combustion chamber reach 840°C. This achievement is occurring in the certain variation of experiment.

Design of Control System for Grain Drying with Solar Collector and Heat Storage

The main problem in the solar drying is the fluctuation of solar radiation that causes drying process takes place un-continuously. The purpose of this research was to design a control system in a grain dryer model using solar collectors and water as a heat storage so that the drying process model, heat storage and its utilization can take place effectively and efficiently. The control method used the ON-OFF control system based on microcontroller ATmega 16. The control system algorithm was based on comparison among air equilibrium moisture content (Me) of environment, Me in the drying chamber and the potential air Me. The results showed that the control system worked well on grain dryers system using solar collectors and water as the medium of heat storage.The average ambient air temperature of 35.6oC, RH of 51.3%, plenum of 35.4oC and the total radiation of 1.66 kWh/m2, the system could dried 5 kg of grains at the top level from initial moisture content of 42.5% d.b to 18.3% d.b and at the bottom level of 42.2% d.b to 16.1% d.b during 10 hours. The water temperature rise although still used, from 32.1oC to the maximum reached 44.2oC and the remaining of 38.8oC.