Development of a Multi Agricultural Products Dryer using Biomass

Natural method of sun drying is weather dependent and time consuming which leads to spoilage and contamination of food crops. This research designed and experimentally tested a multi agricultural dryer using solar energy and biomass, capable of drying agricultural produce anytime of the day in a hygiene environment. The experimental setup consists of the biomass combustion chamber with inbuilt heat exchanger, the dryer and data collection instruments. Tomatoes, Okra and bitter leaf were dried, their relative humidity, moisture content, weight loss and temperature variation in the drying chamber were monitored. The maximum temperature reached in the drying chamber when drying tomato, okra and bitter leaf were 95.7oC, 87.1oC 73.4oC respectively, with a drying rate of 0.1248 kg/h, 0.1876 kg/h, 0.0780 kg/h, respectively at a steady air flow rate of 1.3 m/s. The dryer had an efficiency of 45% and effectiveness of the heat exchanger is 0.077 at an average combustion temperature of 1300oC. The uniqueness of the machine is that it reduces the drying time and products are free from environment contaminations and rodents’ invasion. Thus agricultural crop samples can be preserved year-round irrespective of weather conditions and at a faster rate with the developed machine

Thermophysical Properties of Gmelina Arborea Biodiesel

The depletion of petroleum reserves, rising cost of conventional fuels and the ill effect of emission from the use of fossil fuel on human health and environment have driven scientific research towards the development of alternative source of fuels such as biofuel and biodiesel. Biodiesel is a fuel from a renewable sources and it has the potential of being used as an alternative to fossil diesel in compression ignition engine. Some of the challenges encountered in the use of biodiesel in compression ignition engine are its availability, use of edible oil for its production, cost of biodiesel feedstock and unfavorable properties of biodiesel such as its high viscosity. Presently, there is a search for more inedible oil seeds since the available inedible feedstock are still not enough to replace more than 20 - 25% of the total transportation fuels. The thermophysical properties of the biodiesel which vary from feedstock have a significant impact on the combustion process thereby affecting the overall engine performance and emissions. The aim of this study is to test the compatibility of biodiesel from Gmelina arborea seed oil in the compression ignition engine through its thermophysical properties. The biodiesel was produced using transesterification method and the thermophysical properties tests were carried out. The results showed that the density and viscosity of Gmelina arborea seed oil was 868.8 kg/m2 (at 27.5°C) and 1.882(mm)2/s (at 40.0°C) respectively. It also showed that the biodiesel obtained had a density and viscosity value of 821.2 kg/m3 (at 27.5°C) and 0.794 9 (mm)2/s (at 40.0°C) respectively. Comparing these results with other biodiesel, it was observed that Gmelina arborea oil has a lower viscosity and density than other biodiesel from different feedstocks; therefore it has potential to perform better in the diesel engine in comparison to other biodiesel

PERFORMANCE EVALUATION OF HOT AIR THERMOELECTRIC GENERATOR USING BIOMASS ENERGY SOURCE

Thermoelectric generators are solid-state devices that convert heat into electricity using the Seebeck effect, when there is a temperature difference across a thermoelectric material. This research designed an experimentally tested a thermoelectric hot air generator using sixteen SP1848-27145 modules in two parallel strings. The system consists of a biomass combustion chamber, hot air exhauster, hot and cold side heat exchangers. Voltage, current and temperatures in the combustion chamber, hot air heat exhauster, hot side heat exchanger and cold side heat sink were measured. The hot air exhauster, hot side heat sink and cold side maximum temperatures are 178.3°C, 69.2°C and 44.5°C respectively yielding an open circuit voltage of 64 V and current of 1.99 A in the course of the experiment. The thermal performance of the designed hot air exhauster, hot side heat exchanger and cold side heat were simulated using ANSYS Fluent, for pictorial representation of their temperature contours

Thermophysical Properties of Gmelina Arborea Biodiesel

The depletion of petroleum reserves, rising cost of conventional fuels and the ill effect of emission from the use of fossil fuel on human health and environment have driven scientific research towards the development of alternative source of fuels such as biofuel and biodiesel. Biodiesel is a fuel from a renewable sources and it has the potential of being used as an alternative to fossil diesel in compression ignition engine. Some of the challenges encountered in the use of biodiesel in compression ignition engine are its availability, use of edible oil for its production, cost of biodiesel feedstock and unfavorable properties of biodiesel such as its high viscosity. Presently, there is a search for more inedible oil seeds since the available inedible feedstock are still not enough to replace more than 20 - 25% of the total transportation fuels. The thermophysical properties of the biodiesel which vary from feedstock have a significant impact on the combustion process thereby affecting the overall engine performance and emissions. The aim of this study is to test the compatibility of biodiesel from Gmelina arborea seed oil in the compression ignition engine through its thermophysical properties. The biodiesel was produced using transesterification method and the thermophysical properties tests were carried out. The results showed that the density and viscosity of Gmelina arborea seed oil was 868.8 kg/m2 (at 27.5°C) and 1.882(mm)2/s (at 40.0°C) respectively. It also showed that the biodiesel obtained had a density and viscosity value of 821.2 kg/m3 (at 27.5°C) and 0.794 9 (mm)2/s (at 40.0°C) respectively. Comparing these results with other biodiesel, it was observed that Gmelina arborea oil has a lower viscosity and density than other biodiesel from different feedstocks; therefore it has potential to perform better in the diesel engine in comparison to other biodiesel

Investigation of a Hybridized Cascade Trigeneration Cycle Combined with a District Heating and Air Conditioning System Using Vapour Absorption Refrigeration Cooling: Energy and Exergy Assessments

The insufficiency of energy supply and availability remains a significant global energy challenge. This work proposes a novel approach to addressing global energy challenges by testing the supercritical property and conversion of low-temperature thermal heat into useful energy. It introduces a combined-cascade steam-to-steam trigeneration cycle integrated with vapour absorption refrigeration (VAR) and district heating systems. Energetic and exergetic techniques were applied to assess irreversibility and exergetic destruction. At a gas turbine power of 26.1 MW, energy and exergy efficiencies of 76.68% and 37.71% were achieved, respectively, while producing 17.98 MW of electricity from the steam-to-steam driven cascaded topping and bottoming plants. The cascaded plant attained an energetic efficiency of 38.45% and an exergy efficiency of 56.19%. The overall cycle efficiencies were 85.05% (energy) and 77.99% (exergy). More than 50% of the plant’s lost energy came from the combustion chamber of the gas turbine. The trigeneration system incorporated a binary NH3–H2O VAR system, emphasizing its significance in low-temperature energy systems. The VAR system achieved a cycle exergetic efficiency of 92.25% at a cooling capacity of 2.07 MW, utilizing recovered waste heat at 88 °C for district hot water. The recovered heat minimizes overall exergy destruction, enhancing thermal plant performance