Potential and economic viability of standalone hybrid systems for a rural community of Sokoto, North-west Nigeria

An assessment of the potential and economic viability of standalone hybrid systems for an off-grid rural community of Sokoto, North-west Nigeria was conducted. A specific electric load profile was developed to suite the community consisting 200 homes, a school and a community health center. The data obtained from the Nigeria Meteorological Department, Oshodi, Lagos (daily mean wind speeds, and daily global solar radiation for 24 years from 1987 to 2010) were used. An assessment of the design that will optimally meet the daily load demand with a loss of load probability (LOLP) of 0.01 was performed, considering 3 stand-alone applications of photovoltaic (PV), wind and diesel, and 3 hybrid designs of wind-PV, wind-diesel, and solar-diesel. The diesel standalone system (DSS) was taken as the basis of comparison as the experimental location has no connection to a distribution network. The HOMER® software optimizing tool was engaged following the feasibility analysis with the RETScreen software. The wind standalone system (WSS) was found to be the optimal means of producing renewable electricity in terms of life cycle cost as well as levelised cost of producing energy at $0.15/(kW$h). This is competitive with grid electricity, which is presently at a cost of approximately $0.09/(kW$h) and 410% better than the conventional DSS at a levelized cost of energy (LCOE) of $0.62/kWh. The WSS is proposed for communities around the study site

Feasibility and techno-economic assessment of stand-alone and hybrid RE for rural electrification in selected sites of south eastern Nigeria

The study assessed the feasibility and economic viability of solar and wind energy resources as sustainable electrical source for rural communities unconnected to the grid. Rural communities made up of 200 homes, a school and health centre were conceived. Specific electric load profile of 358 kWh per day, with 46 kW primary peak load and 20 kW deferrable peak load, was formulated to match the rural communities. The assessment of the design that will optimally meet the daily load demand with a loss of load probability of 0.01 was carried out by considering three stand-alone applications of photovoltaic (PV), wind, diesel, and a hybrid design of wind-PV. The result showed that a cost-effective alternative for power generation at the different sites surpassed the conventional diesel stand-alone system. Also, the embedded generation analysis showed that 5 of the 6 configurations yielded profits for a 10-year project life in line with the present national tariff orde

Assessing the emission factors of low-pour-fuel-oil and diesel in steam boilers

The purpose of this study is to examine the emissions effects resulting from the use of low pour fuel oil (LPFO) and diesel fuels in industrial steam boilers operation. The method of ultimate analysis of the products of combustion and emissions of pollutant analysis were used to estimate the annual rate of emissions of boilers. The results shows that the levels of uncontrolled boiler emissions on the environment can lead to increased greenhouse effects, global warming, and pollution and toxilogical impacts on human health. Only carbon monoxide emission was found to vary with the levels of oxygen generation in the products of combustion, while other substances were generally in relation to constituents and rates of consumption of fuel

Exergetic Modelling of Oil-Fired Steam Boilers

The performance variables and potential for energy savings in oil-fired industrial steam boilers were studied. Operational parameters of steam boilers using low pour fuel oil (LPFO) and diesel were used to determine thermodynamic properties of material streams and exergetic parameters. Analysis of thermodynamic properties on exergetic performance of boilers was conducted. Exergetic models developed are also presented. The ratio of the energy to exergy efficiencies of the heat exchanging unit and of the entire steam boiler was determined as 1.4 and 1.8614 respectively. The average overall boiler exergy destruction decreased by 14.62%, as the evaporation ratio increased from 10 to 14 though heat loss in boiler was found to increase with increases in evaporation ratio. Developed models in this study could be employed to analyse and estimate exergetic performance indices of oil-fired steam boilers in order to enhance their efficiencies and reduce energy wastage.http://dx.doi.org/10.4314/njt.v33i4.1

Energetic performance analysis of drying agricultural products integrated with solar tracking

Renewable energy sources such as solar energy for drying purposes in a more effective and efficient way is inevitable for preservation of agricultural products in developing nations with inadequate access to electricity. This study investigates the effects of using a solar tracking device on the energy performance of drying processes. Three categories of drying conditions were carried out simultaneously; for a fixed solar box dryer, a solar box dryer aided by a tracking device, and open air drying over an effective total drying time of 6 hours each day, for 5 days. The average solar intensity for the open air, fixed and tracking collector drying were determined as 156.54, 180.72 and 186.81, corresponding to average drying temperatures of 32.17, 43.31 and 45.93 respectively. Solar intensity of open air drying can be increased by as much as 15.45-19.34% if fixed and tracking solar collector systems are employed. Integration of a tracking device enhances the solar intensity of collectors during drying; which translates to accelerated drying process and drying efficiency. http://dx.doi.org/10.4314/njt.v35i4.1

Methodology for Energy and Energy Analysis of Steam Boilers

This paper presents a framework of thermodynamic, energy and exergy, analyses of industrial steam boilers. Mass, energy, and exergy analysis were used to develop a methodology for evaluating thermodynamic properties, energy and exergy input and output resources in industrial steam boilers. Determined methods make available an analytic procedure for exergetic analysis on steam boilers for appropriate applications. Chemical exergy of the material streams was considered to offer a more comprehensive detail on energy and exergy resource allocation and losses of the processes in a steam boiler. Keywords: exergy, energy, steam boilers, chemical exergy, exergy destructio

Evaluation of Cocoyam-Soybean Flour Blends and Sensory Properties of the Amala Dumpling

Amala, a staple food among the Yoruba people of South West Nigeria, is mostly produced from yam. Since yam is known to be mostly carbohydrate and soybean is a legume with an appreciable quantity of protein, efforts have been made to prepare amala from the blends of cocoyam and soybean flours. The protein content of the flour blends ranged from 3.73% to 13.81%. In general, there was increase in the concentration of protein with increasing level of soy flour substitution. Unlike protein, the crude fibre content of the flour blends decreased with increasing supplementation of soy flour. Increase in oil content of the flour samples, with increasing addition of soy flour, predisposes the samples to shorter shell life and off flavor because of liability to rancidity. The lowest bulk density of 0.78 g/cm3 was recorded for sample A (100% cocoyam flour) and hence none of the flour blends could be considered as a complimentary infant substitute. In general, supplementation of cocoyam flour with soy flour enhanced the concentrations of protein, ash and dietary fibre. Therefore, it is hoped that consumption of cocoyam amala supplemented with soy flour, a cheap source of plant protein, will not only create dietary diversity, it will make more protein available for the consumers and thus help in alleviating the problem of protein energy malnutrition in developing regions of the world

Techno-Economic Assessment of Renewable Electricity for Rural Electrification and IT Applications in Selected Sites Across the Geopolitical Zones of Nigeria

This study presents an energy resource assessment for six sites, one from each geo-political zone of Nigeria. It assessed the feasibility and economic viability of RE resources that can provide sustainable electricity and enhance ICT development for rural communities cut off from the national grid. Hypothetical rural communities made up of 200 homes, a school and health centre was conceived. Specific electrical load profile was developed to suite the rural communities. The required load was analyzed as 358 kWh per day, with 46 kW primary peak load and 20 kW deferrable peak load. The meteorological data utilized were obtained from the Nigeria Meteorological Department spanning 1987- 2010. Assessment of the design that will optimally meet the daily load demand with LOLP of 0.01 was carried out by considering standalone PV, Wind and Diesel, and a hybrid design of Wind-PV. The Diesel Standalone system was taken as the basis for comparison. The optimization tool employed after the feasibility analysis with RETScreen® software was the HOMER® software. The outcome showed that the most economically viable alternative for power generation at most of the sites is the wind standalone system. It proved to be the optimal means of producing renewable electricity in terms of life cycle cost and levelised cost of energy which ranged between $0.129/kWh for Jos and$0.327/kWh for Benin City. This is very much competitive with grid electricity. Renewable technologies could then become the subject of rigorous pursuit for rural electrification and ICT development in local communities around the sites

Modeling and Analysis of Fouling Behaviour in Plate and Frame Heat Exchanger

The fouling of heat exchangers in the oil and gas industry is not only a recurring challenge in refineries but it is also becoming a challenge in crude oil production and treatment facilities where heat exchangers are deployed to cool the crude oil temperature downstream of stabilization system prior to storage. A predictive mitigation approach to addressing fouling in heat exchangers remains the most viable option to avoid production train capacity limitations, unplanned shutdown and attendant loss of revenue. Considerable researches have been carried out which lead to the development of models used for predicting fouling resistances in shell and tube heat exchangers. However, this study focused on evaluation of the performance of a plate and frame heat exchanger utilized in cooling of crude oil prior to storage in a cargo tank for export. It also developed a fouling resistance suitable for forecasting the exchanger performance and predicting the maintenance management scheme. The data employed were continuously measured for three years and employed for the analysis.  It found that the lower the hot stream approach temperature, the more the fouling resistance. In addition, the work validates that as the fouling resistance increases with time, the efficiency of the plate and frame heat exchanger diminishes