Influence of temperature difference (water-cover surface) on the performance of a compact hemispherical solar still

The study investigated the influence of temperature difference (ΔT) between evaporative and condensing surface temperature on water productivity of hemispherical solar still. The still was developed, tested and evaluated under the climatic conditions of Ile-Ife, Nigeria, to obtain an average distillate yield per hour per day for different combination of basin temperature, water temperature, transparent cover temperature, ambient temperature and solar intensity. Results indicated a decrease in the hourly water yield as (ΔT) increases. Regression analysis revealed that ΔT has no significant influence on the hourly water yield (P > 0.05). Maximum water productivity was obtained for a low condensing surface temperature and a high evaporative surface temperature. The study concluded that the improvement on water productivity of solar still can be achieved by enhancing the evaporative and condensing surface temperature. Methods for obtaining higher evaporating temperature should be sought in order to boost water productivity of solar stills. Keywords: Temperature difference, Evaporative surface, Condensing surface, Hourly water yield, Heat losses

Effects of Soybean Methyl Ester on the Performance Characteristics of Compression Ignition Engine

Depletion and hazardous gas emissions associated with fossil fuels have caused scientists and global attention to focus on the use of "alternative, eco-friendly substitutes for use in Compression IgnitionEngines. In this work, biodiesel was produced by trans-esterification of soybean obtained from a Nigerian market using Sodium Hydroxide (NaOH) as a catalyst." After the production, the physical properties (specific gravity to kinematic viscosity and net calorific value) of the Soybean-biodiesel produced and petrol diesel obtained from a filling station in Nigeria were determined, and these properties conform to conventional standards (ASTM). A cummins-6V-92TA DDEC diesel (Compression ignition, CI) engine was run on various biodiesel-petrol diesel blends (0/100, 10/90, 20/80, 30/70 and 40/60), the B20 (blend 20/80) was found to be the most satisfactory

A Comparative Performance and Emission Analysis of Blended Groundnut Oil and Mineral Oil Based Lubricants Using a Spark Ignition Engine

This paper presents the performance and emission behaviour of a spark ignition engine run on groundnut oil blended lubricants. However, for the purpose of comparism, benchmark tests were carried out on multigrade and monograde motor oils. A 5.0 h.p engine test-bed incorporated with an A.C dynamometer and flue gas analyzer was used to conduct the tests. At maximum engine speed, the groundnut oil blended lubricants generated an exhaust temperature of 6.02% higher than multigrade oil, and 6.26% higher than monograde oil. The brake power was 12.70% and 10.94% higher than the monograde and multigrade oils. In terms of fuel economy, the monograde and groundnut oil blended lubricants are 7.50% and 2.18% higher than multigrade oil respectively. It is shown that as the proportion of viscosity modifier in the oil sample increases, exhaust temperature, brake power, brake mean effective pressure (b.m.e.p) also increases, while the specific fuel consumption diminishes. At various speeds, CO2 level emitted by the use of groundnut oil blended lubricants was observed to be higher than it was the case for multigrade and monograde oils. In the light of the fast depleting fossil fuel reserve in Nigeria, this work has demonstrated the feasibility of using groundnut oil blends as lubricant substitutes in spark ignition engines

Energy output assessment of Lafia-Obi coal in a fluidized bed combustor

This work investigated the energy output from the fluidized bed combustion of Lafia-Obi coal using five range of fuel equivalent diameters (FED) of 125 μm, 250 μm, 355 μm, 2.5 mm and 5.0 mm. Energy output in response to variation in bed temperature, FED, bed pressure, and fluidizing velocity was examined in the fluidized bed heat exchanger. Results indicated an increase in heat transfer rate by 80, 11 and 25% when 5 mm coal was reduced to 355, 250 and 150 μm respectively. Bed temperature increased by 8% for 355 μm and decreased by 6% when 5.0 mm coal was fired. Higher bed pressure was observed when larger particle sizes (5.0 and 2.5 mm) were fired. This resulted in poor bed temperature and increasing fluidization velocity and thus, reduced steam discharge temperature at the heat exchanger outlet.Keywords: Lafia-Obi coal, energy output, fluidized bed, particle size, bed temperature, combustion efficienc

Thermal Performance of Improved Charcoal Stove as A Clean Development Mechanism Project – A Case Study of Bauchi

Improved cook stoves (ICS) are known to ensure efficiency in the use of traditional fuels, reduce smoke emission and associated health hazards during cooking and reduce cooking time. Another benefit of ICS is in mitigating the effects of climate change. This paper presents the thermal performance and achievable emission reductions by ICS for daily cooking in households aroundBauchi.It  evaluatesan ICS using the International Workshop Agreement (IWA) which rates cook stoves on four indicators (Indoor emission, total emission, efficiency/fuel use and safety) each indicator is rated along five tiers (0: lowest performing to 4: highest performing).The evaluation focused on efficiency/fuel use. The benchmark values for thermal efficiency, fuel use and energy use are 35%, 0.310kg and 7928kJ.This shows that the ICS offers modest improvements in fuel use and it is rated as a tier 3 ICS. A carbon savings of can be achieved on an annual basis assuming all rural and urban households in Bauchi employ ICS for their daily cooking

Removal of arsenic (V) from aqueous solutions using chitosan-red scoria and chitosan-pumice blends

In different regions across the globe, elevated arsenic contents in the groundwater constitute a major health problem. In this work, a biopolymer chitosan has been blended with volcanic rocks (red scoria and pumice) for arsenic (V) removal. The effect of three blending ratios of chitosan and volcanic rocks (1:2, 1:5 and 1:10) on arsenic removal has been studied. The optimal blending ratio was 1:5 (chitosan:volcanic rocks) with maximum adsorption capacity of 0.72 mg/g and 0.71 mg/g for chitosan:red scoria (Ch-Rs) and chitosan:pumice (Ch-Pu), respectively. The experimental adsorption data fitted well a Langmuir isotherm (R-2 > 0.99) and followed pseudo-second-order kinetics. The high stability of the materials and their high arsenic (V) removal efficiency (similar to 93%) in a wide pH range (4 to 10) are useful for real field applications. Moreover, the blends could be regenerated using 0.05 M NaOH and used for several cycles without losing their original arsenic removal efficiency. The results of the study demonstrate that chitosan-volcanic rock blends should be further explored as a potential sustainable solution for removal of arsenic (V) from water

Flame Behaviour Comparison of Building Ceiling Composite using Combustion Calorimeter

This study determined the heat of combustion characteristics of selected building ceilings materials. The study was intending to appraise the flame affinity or retardance of building ceiling materials during combustion. Careful selection of ceiling composite was carried out in areas like Osun state, Ogun state, Lagos state, and Kaduna State. The heat of combustion was determined, having identified the heating value from the XRY-1C Oxygen Bomb Calorimeter. The heat flux and heat release rates were determined from the results of the combustion experiment. Based on the data obtained from the discrete experiments, the combustion integrity of the samples was appraised. Particleboard has the highest heat of combustion of 45.666J/kg, while asbestos failed to ignite. Other Polyvinyl chlorides (PVC) left ≤ 0.0007kg of char after combustion and became deliquescent after long minutes of exposure to air. The heat release rate is highest with particleboard, 118.9219 J/s, and lowest with sample 7, 2.230 J/s. The study thus establishes that PVC is safer in terms of combustion properties compared to plant-based building ceilings. Asbestos has the overall most reliable properties, but for asbestosis, its use isn't safe for use. It is necessary to develop building ceilings with flame retardant characteristics of asbestos as an alternative to it