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| dc.contributor.author | TEFERA, EWNETU | |
| dc.date.accessioned | 2020-12-04T05:32:52Z | |
| dc.date.available | 2020-12-04T05:32:52Z | |
| dc.date.issued | 2020 | |
| dc.identifier.uri | http://hdl.handle.net/123456789/11718 | |
| dc.description.abstract | A solar dryer assisted by biomass back-up heater was designed and manufactured from locally available materials to dry maize. This study tried to address the problem associated with the fact that solar dryers are efficiently operational only when there is sufficient solar energy. The dyer is composed of a solar collector, drying chamber, biomass back-up heater, and airflow systems. The solar collector has a length and width of 2 m×1 m respectively and is enclosed with a transparent glass that allows the solar energy into the collector. The air gap has a 0.05 mm. Therec is double-Y duct that connects the solar collector to the drying chamber. The drying chamber is essentially a batch type dryer and measures 1 m × 1 m × 1 m. It accommodates three drying trays made from mild steel wire mesh. This chimney serves as the exit for the moisture air sucked by the fan and the fan also increases the speed of air. The measurement taken to evaluate the performance of this dryer are temperature, moisture content, solar irradiation, and airspeed. The average temperature difference between the ambient and the collector outlet was recorded as 9.6oC, and 12.8oC in the solar and biomass assisted dryer respectively. The daily average solar insolation for the test periodes of October and December at the site was recorded as 673 W/m2. When the system is loaded with 50 kg of wet maize grain at an initial moisture content of 21.3 % and dried to 14.4 % moisture content in 45 hours drying time in the solar dryer 4.03 kg of moisture is removed. A 50 kg of wet maize grain at an initial moisture content of 22.9 % and dried to 14.2 % moisture content in 27 hours in solar dryer assisted by biomass back-up heater 5.06 kg of moisture is removed. Solar dryer collector efficiency was estimated as 64.2% with average drying rate of 0.0746kg/hr. Sola dryer system efficiency was 20.8% and solar assisted dryer efficiency was 4.3% | en_US |
| dc.language.iso | en | en_US |
| dc.subject | Thermal Engineering | en_US |
| dc.title | EXPERIMENTAL TESTING OF SOLAR MAIZE DRYER ASSISTED BY BIOMASS BACK-UP HEATER | en_US |
| dc.type | Thesis | en_US |
