A major focus of existing literature on energy conservation is the modelling and quantification of energy savings and the corresponding carbon dioxide emissions from lightings. While many studies have established theoretical frameworks concerning these issues, very little documentation exists relating to energy savings and emission levels in students' hostels. This paper considers the lighting efficiency improvement of four University of Lagos halls of residence for the purpose of quantifying energy saving and the minimization of carbon dioxide that can be made. Compact fluorescent lamps are considered alternatives to the current primary usage of conventional fluorescent and incandescent bulbs. The existing electricity consumption data obtained from energy audit are used in combination with conversion factors to estimate the annual CO 2 contributed to the atmosphere by lighting in each of the buildings. The result of the study shows that over 45% reduction in carbon dioxide emission can be achieved. There is a lot individuals can do to reduce the emissions, for example, using energy saving appliances, turning off appliances when not in use, less use of fossil fuels, are simple measures that can be adopted to reduce annual carbon footprint, improve economic growth, enhance environment, health and save the planet.

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An organic material is proposed as a sustainable sensitizer and a replacement for the synthetic sensitizer in a dye-sensitized solar cell technology. Using the liquid extract from the leaf of a plant called Mimosa pudica (M. pudica) as a sensitizer, the performance characteristics of the extract of M. pudica are investigated. The photo-anode of each of the solar cell sample is passivated with a self-assembly monolayer (SAM) from a set of four materials, including alumina, formic acid, gelatine, and oxidized starch. Three sets of five samples of an M. pudica-based solar cell are produced, with the fifth sample used as the control experiment. Each of the solar cell samples has an active area of 0.3848cm 2. A twodimensional finite volume method (FVM) is used to model the transport of ions within the monolayer of the solar cell. The performance of the experimentally fabricated solar cells compares qualitatively with the ones obtained from the literature and the simulated solar cells. The highest efficiency of 3% is obtained from the use of the extract as a sensitizer. It is anticipated that the comparison of the performance characteristics with further research on the concentration of M. pudica extract will enhance the development of a reliable and competitive organic solar cell. It is also recommended that further research should be carried out on the concentration of the extract and electrolyte used in this study for a possible improved performance of the cell.

This paper seeks to increase interest level on energy efficiency by bringing to fore payback-period assessment of implementing energy-efficient measures that could help achieve sustainable production processes in a typical medium scale printing manufacturing industry in Lagos, Nigeria. Several energy efficiency measures have been suggested based on identifiable energy management opportunities within this industry. The method used for the economic evaluation and feasibility study is payback period; this approach is aimed at providing guidance for a quick and informed decision on the implementation of the energy efficiency measures identified. The payback for two of these measures namely; turning off equipment when not in use and replacement of drive belts on large motors with energy efficient cog belts, have been found to be immediate. When standard fluorescent lighting and incandescent bulbs are replaced with energy efficient lamps and bank of capacitors are installed to improve the power factor of the motors, the company will recoup its initial investment in less than one year. Also, purchasing and installing an advanced electronic meter with data logging capability to help monitor electrical demand has been shown to give the highest payback of 2.4 years. These payback period results have indicated that investment in the recommended energy efficient technologies are economically viable and worthy of implementation. With this analysis, management of manufacturing industries can now make informed economic decision towards productivity improvement and sustainability.

Computational fluid dynamics was applied in the prediction of the effect of inlet temperature on the drying time of fish in a cabinet rotary dryer. On completion of the simulation, the temperature distribution of the air (fluid domain) within the drier at different inlet air temperatures and time intervals was obtained. Inlet air temperatures ranging from 35oC to 55oC was simulated for a time interval of 10 minutes to 120 minutes so as to examine the influence of inlet temperature on the drying process of fish. Based on this temperature range, it was observed that the ideal drying time for the fish which satisfies the condition for efficient fish drying for all five inlet air temperatures of the fish is 70 minutes. Furthermore, it can be observed that it takes about 120 minutes for the inlet air temperature of 50 degrees Celsius to attain a cabinet drying temperature of 316K (43°C) while it takes only 70 minutes for the inlet air temperature of 55 degrees Celsius to attain the same temperature under the same condition.