Biomass energy accounts for more than 92 percent of overall energy consumption in Ethiopia. As a result, Ethiopia is one of the world’s most biomass-dependent countries. The high reliance on wood fuels and agricultural residues for fuel harms society’s social, economic, and environmental well-being. This study aims to create and test the quality of fuel briquettes made from the coffee husk. Also built and produced are a carboniser/charcoal kiln, a manually operated molder system, and a briquette stove for burning the manufactured briquette. The carboniser converts 15 kg of raw coffee husk into 6 kg of carbonised char in 25 minutes, and the manually operated briquette molder can press 30 kg per hour. The efficiency of converting raw coffee husk into carbonised char content was 40.12%. In the geological survey of Ethiopia, the geochemical laboratory directorate received triplicate samples of the fuel briquette charcoal for analysis. Moisture content, fixed carbon content, ash content, sulfur content, and calorific value were determined using a bomb calorimeter and a ceramic lining furnace. Physical properties of fuel briquettes ranged from 10.03% moisture content, 970 kg/m3 density, 81% fixed carbon, 5.15% ash content, 0% sulfur, and 30.54 Kcal/kg higher heating value, according to laboratory results. The results of the study revealed that the coffee husk fuel briquettes produced have more positive characteristics. Fuel briquettes were cost-effective and environmentally friendly and reduced deforestation compared to firewood. This study clearly shows that briquettes made from coffee husk could be used as an alternative energy source when this kind of waste is well managed.

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A series of tests were conducted to investigate the performance of a solar tunnel dryer for drying ginger. To supply hot air to the dryer, two axial flow fans with a power rating of 28 W, a supply voltage of 220 V, and a 50 W photovoltaics (PV) module were employed. By dividing the 8.5-meter-long solar tunnel dryer into four equal portions every thirty minutes, solar radiation, dry air temperature, ambient temperature, relative humidity, and air velocity were measured at five solar tunnel dryer stations. The hot air temperature at the collector output grew from 34°C to 65.5°C for an 8-hour operation in the no-load condition when the solar radiation was changed between 540 and 820 W/m2. At 9:00 a.m., the average maximum temperature was 30°C. During the loading operation, the temperature was 77°C at 1:00 p.m. The moisture content of sliced ginger was reduced from 90.4 to 11.8% on a wet basis using the solar tunnel dryer. With a solar collector area of 6 m2, open sun drying takes 40 hours to achieve the same wet basis condition. A total of eight experiments were carried out, both with and without loads. The dry air temperature at the collector outlet ranged from 34.0 to 65.5 °C. As the drying efficiency, collector area, and time savings improve, the drying time decreases. The ginger is kept in a controlled area, resulting in high-quality dried ginger. The solar tunnel dryer showed a net saving in drying time of 40% over open sun drying.

Manufacturing industries use a huge amount of power to heat water. The ability to control pollutant gas species released from the company by improving the efficiency of combustion reduces global warming and energy bills associated with water heating. In this study, computational fluid dynamics (CFD) thermal analysis of a biomass gasifier and heat exchanger combined system has been used to study the effect of the concentration of species, such as CH4, CO2, and CO, on the gasification temperature. The power consumed by boilers for water heating in industries, hotels, restaurants, and other domestic hot water heating is, to some extent, to substitute by a combined system. The model and syngas energy analysis of the integrated system was investigated by assuming a eucalyptus wood chip as fuel from the literature with 5%wb ultimate and 10% proximate values to analyze the gasification performance. The reactor was designed to supply syngas gas energy through the pipe. The gasification system was investigated at temperatures ranging from 298 to 990 K. This range of temperature in the gasifier is enough for water heating applications. The CFD model is developed and validated with the experimental results obtained in the literature. Several parameters, such as syngas molar composition and mass fraction, lower heating value of biomass, gasifier efficiency (67.3%), biomass energy, product gas energy, energy gain by the heat exchanger, and hot water outlet temperature, were examined by varying temperature. As the result shows, the species concentrations in the gasifier vary with temperature and gasifying agent. To optimize the transfer of heat from the heat exchanger tube to cold water, the syngas circulation time inside the inner tube should be increased by making the inner tube-shaped zigzag.