Design of eco-friendly fixed bed dryer based on a combination of solar collector and photovoltaic module

A study to develop a convective eco-friendly fixed-bed solar dryer is presented in this article. The aim of this study was to design an efficient eco-friendly fixed bed dryer using solar collector and solar photovoltaic panel with a forced convective system. The design consists of a V-corrugated solar collector, a centrifugal fan, a solar photovoltaic module (100 WP) and a drying unit in the mini-silo model with five layers. The dryer performance test was conducted in September, October, and November 2017 in Malang, East Java, Indonesia. The observation showed that the temperature of the solar collector and the first layer of the drying unit could reach 40-70°C on a sunny day and 30-50°C in cloudy/rainy conditions. The efficiency of the daily collector varied from 20% to 50%. Based on a multiple regression analysis, it showed that some variables (solar intensity, voltage of photovoltaic panel, air speed around the blower, air collector velocity, collector relative humidity, ambient temperature and relative humidity temperature) significantly influenced the collector temperature. The result of drying simulation using red pepper showed that the design has a potential to be used as an eco-friendly fixed bed convective drying. Based on the empirical model, the drying time needed to reach 12% of moisture content (wet basis), respectively, was 5-6 days for the first tray, 8-9 days for the second tray and 9-10 days for the third tray in rainy season.