Biodiesel production from waste cooking oil is a potential feedstock to alternative fuel sources. Produced alternative fuel sources were to have a strong emphasis on energy efficiency to substitute the declining world supply of fossil fuels while also improving emission characteristics in diesel engine applications. The development of industrialization and mechanization causes increased fossil fuel consumption and its usage. This study aimed at an experimental investigation of biodiesel blended fuel combustion efficiency for single-cylinder diesel engines under varying engine loads at constant engine speed 1500 rpm. The transesterification process was used to produce biodiesel from waste cooking oil using NaOH as catalysts. Biodiesel reaction takes place with oil to methanol ratio of 6:1 at 60 °C reaction temperature for 90 min with 600 rpm stirring speed while 90% yield gained. Eight sample biodiesel blends were prepared with percentage value B5%, B10%, B15%, B20%, B25%, B30%, B35%, B40% v/v and B100% to investigate the effect of biodiesels on engine performances. The experimental result reveals that the mixed biodiesel blends have lower average value in terms of brake torque, brake power, and brake thermal efficiency than diesel fuels as a percentage of 16.79%, 4.08%, and 27.9% respectively. In addition, the average BSFC of biodiesel blends was increased by 4.8% than baseline diesel fuel. Related to exhaust gases emission test results were shows that the average CO and HC emissions decreased by 52.2% and 60% with increasing loads and blends and the increment of CO₂ and NOx by 28.1% and 45.4% respectively than baseline fuel with increasing blends and loads. Biodiesel derived from waste cooking oil was less costly and environmentally friendly and viable to substitute petro-diesel.

The performance of gasification for Injera baking was explored in this study, as well as the effects of moisture content, and primary and secondary airflow rates. Primary air is used in the reactor of a biomass gasifier, which creates syngas that is burned by secondary air on the mitad's bottom side. An average temperature of averaged 185 °C at the center and 170 °C away from the center was observed; the size of the cone determines the temperature distribution on the metal surface. The reactor's narrower cone diameter allowed for a greater temperature only in the center and a more variable baked Injera eye appearance. The cone diameter has been reduced to 0.15 m of the mitad diameter to improve the temperature distribution on the mitad surface. The gasifier temperature is 800 °C when the air/fuel ratio is 5.8 kg/kg and the moisture content of the wood is 16%. Gasification is improved by heating the primary air and changing the air-fuel ratio. The findings revealed that pre-heated air is more efficient for gasification and saves money on baking and fuel. Fuel efficiency (0.45) and time savings (0.12) were discovered in the new gasifier. Between gasification temperatures of 650 and 800 °C, an effective Injera baking temperature (170–185 °C) on the mitad surface was attained. Following the tests, the average specific wood fuel consumption (1.414 g/kg), char residue (317 g), and average Injera baking time were calculated. For each test of one baking cycle, this was found at the burning rate capability of both stoves, which is 6 kg/hr. Therefore, the fuel consumption and burning rate of fuel are depending on the amount of airflow rate.

A series of laboratory studies were undertaken in Gondar to explore the effects of temperature, air mass flow rate, heating rate, and residence duration on cud and waste paper char yields in slow pyrolysis. Cud and waste paper were burned at a low pyrolysis temperature to generate biochar (167 °C). The rate of decomposition depends on the feedstock and the process conditions. The biochar yield is mostly governed by the applied regulated temperature and airflow rate, according to the data. During the experiment, the main airflow rate delays the pyrolysis process.

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.

In this study, a series of laboratory experiments were conducted to investigate the effects of slow pyrolysis parameters of temperature, air mass flow rate, heating rate, and residence time on cud and waste paper char yields. Cud and waste paper were heated with a slow pyrolysis temperature (167 0 C) to produce the biochar. The degree of decomposition depends on the feedstock used and process conditions. As the results revealed that the biochar yield, depends mainly on the applied controlled temperature and airflow rate. During the experiment, the primary airflow rate makes the process more slowly pyrolysis. Both primary and secondary air inlet opening at the same time provides high temperature and less biochar yield. The experiment was conducted under a slow pyrolysis temperature of 167 0 C, moisture 15%, and air mass flow rate of (0.35 - 1.5kg/s). At this temperature; 30kg of feedstock, cup, and paper in the reactor produces 10kg- 23kg and 10-20kg respectively of biochar yield at the same airflow rate of 0.35m/s. Temperature gradient appears and tends to increase as the airflow rate increases within the limited values. But the biochar yield reduces as the pyrolysis temperature and airflow rate increase.

Fruits have a tendency to spoil and lose quality over time when stored, so it is important to take precautions to preserve their vitamins, nutrients, and overall properties. Outdated fruit and vegetable preservation methods in rural regions underscore the need for a more effective way to prolong fruit life. In order to preserve the freshness and quality of fruits, cylindrical fruit preservation, or CFP, was developed in this study. The study evaluated how humidity, temperature, and duration affected the cylindrical fruit preserver's (CFP) ability to retain moisture. The study sought to forecast the temperature distribution inside the cylinder walls, as well as the water and humidity loss within the chamber during fruit storage, using mathematical models. By regulating temperature, heat transport, humidity, and other factors fruits can be kept at consistent moisture levels. The daily variation in Gondar's temperature, which ranged from 22 to 25 °C, and humidity, which varied from 40 to 99%, were included in a mathematical equation to study the influence of temperature on humidity. The results showed that when other variables are ignored and maintained constant, temperatures and humidity are linearly related to moisture loss in the preservation process. When the preserver temperature is changed from 297K to 295 K, the moisture content is reduced from 80 to 64%. Methods such as multi-state modeling, 3D modeling of conjugate models, and model construction for hybrid technology are some of the future advances in fruit moisture conservation mathematical modeling.