Browsing by Author "Inambao, Freddie Liswaniso."

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CFD Modelling and performance evaluation of a forced convection mixed-mode solar grain dryer with a preheater.
(2021) Angula, Johannes Penda.; Inambao, Freddie Liswaniso.
Solar drying of agricultural food products as an art of food preservation has been in existence since the 17th century. In most tropical and subtropical countries, the drying process of harvested agricultural products such as grains is mainly carried out using the method of open-air drying or sun drying to preserve the harvest. With the advances of technology over time, new solar drying methods such as indirect and mixed-mode solar drying are evolving. Mixed-mode solar dryers are among the most efficient solar drying methods for improving the harvest and storage of grains. One of the advances in the development of solar dryers is the use of computational fluid dynamics (CFD) and computer-aided design (CAD) codes to model, simulate, and analyze dryer systems' performance. This study was conducted in two phases. The first phase entailed the use of CAD and CFD codes to model and simulates a forced convection mixed-mode solar grain dryer integrated with a preheater. A 3D model was developed with great accuracy using SolidWorks code and, the CFD simulation was carried out using ANSYS Fluent code. In the second phase, an experiment was conducted using an existing indirect solar dryer which was modified and converted to a mixed-mode solar dryer suitable for the study. The modeling and simulation results were validated against experimental results to evaluate the dryer system' performance. The study was conducted at various airflow speed and preheater temperatures ranging from 0.5 m/s to 2 m/s and 30 ℃ to 40 ℃, respectively. The type of grains used in the experiment were corn grains whereby 72 freshly harvested maize ears/cobs were dried. The study was conducted under the weather conditions of Durban, South Africa, at the University of KwaZulu-Natal. This study aimed to investigate solar drying technologies towards performance enhancement of a forced convection mixed-mode solar grain dryer that incorporated a preheater through modeling and optimization. This approach was followed in order to develop a better understanding of the effects of forced convection and air preheating on airflow distribution and temperature distribution within a solar dryer. The results from both the CFD modeling and experiment were satisfactory, resulting in a correlation with a maximum relative error of 16.3 %. The dryer system's performance results indicated a maximum thermal efficiency of 58.8 % with a corresponding drying rate of 0.0438 kg/hr. The minimum thermal efficiency for the dryer system was 47.7 %, with a corresponding drying rate of 0.0356 kg/hr. The fastest drying time of maize ears was achieved in 4 hours and 34 minutes from an initial moisture content of 24.7 % wb to 12.5 % wb. At the same time, open-sun drying yielded the slowest drying time of 15 hours from an initial moisture content of 27.3 % wb to 12.7 % wb. There was a significant improvement in the dryer system's performance, whose initial efficiency was 36 % when operating as an indirect solar dryer. These results are a clear indication that using a solar dryer system in mixed-mode operation with forced convection and the assistance of a preheater or backup heater can significantly improve drying processes and increase food preservation. The study further presents design concepts of incorporating cost-effective solar thermal energy storage systems that can be implemented to optimize solar dryers. In this case, solar energy can be harvested and stored during peak sunshine hours and made available for usage during off-peak sunshine hours.
Combustion studies of biodiesel fuel from moringa, jatropha and restaurant oil.
(2016) Onuh, Emmanuel Idoko.; Inambao, Freddie Liswaniso.
Biodiesel is a renewable alternative to finite diesel and, has the capacity to reduce emission and broaden energy access particularly in sub-Saharan Africa where economic growth has been, to some extent, constrained by global warming and a lack of universal access to sustainable source of energy. In the transport sector, a niche exist for biodiesel derived from non-edible feedstock such as waste oil, jatropha and moringa in sub-Saharan Africa. Extraction of oil from jatopha and moringa were achieved via manual as well as soxhlet method using normal hexane, petroleum ether and distilled gasoline. A numerical property prediction scheme was implemented (and validated with experimental data) to obtain the thermo- physical as well as the transport properties of the resulting fuel for the various samples. This prediction scheme reduced the number of experimentation for property determination from nine to one per sample. The pure fuel samples were evaluated in a 3.5kw diesel engine to determine their performance and emissions. The Brake Specific (BS in g/kWh) emissions across the full load spectrum were benchmarked against the United State Environmental Protection Agency (US, EPA) and the European Union (EU) emission caps. This study is a follow-up to an earlier work by Eloka Eboka which focused on the determination of optimal production process for biodiesel using different technique and catalyst. In that work, the engine test was a qualitative evaluation of different mixture ratio forming new hybrids and the engine test protocol did not follow the ISO 8178-4:2006 test cycle categorization nor was the emission benchmarked against the EPA/EU emission caps (both of which were implemented in this study). The extraction results not only confirmed normal hexane solvent and soxhlet method as the optimal means of extraction (with a 37.1% and 51.8% yield for moringa and jatropha respectively) but, gave hint of the potential of distilled Gasoline as a viable solvent (with a 40.2% and 34.1% yield for moringa and jatropha respectively). The validated numerical prediction scheme reduce research cost and time without compromising accuracy. The performance and emission revealed that the Brake specific fuel consumption (BSFC) and brake thermal efficiencies for both diesel and the biodiesels only differ marginally (±4% and ±5 respectively at peak load). Carbon monoxide (CO), unburnt hydrocarbon (UHC) and particulate matter (PM) emissions (in part per million-ppm) showed decreasing trend with load increase and were lower than those of diesel. Oxides of nitrogen (NOX) emission for the biodiesel were lower than those of diesel. The Brake Specific (BS) emission results in comparison to the EU and EPA regulation showed various level of compliance and non-compliance to the emission limits. The result also showed that samples with higher proportion of unsaturated FAME have poorer engine performance and results in higher unwanted emission than saturated FAME. In broad terms, engine retrofitting and novel design could effectively bridge the performance and emission gaps observed between diesel and biodiesel. A multi-blend (saturated and unsaturated FAME) and multi-strategy (Modular kinetic and premix/DI) was recommended as a remediation strategy. For numerical prediction purpose, a 3D CFD with multi zone and detailed chemistryusing KIVA-3V code was proposed.
Combustion studies of hybrid nanoadditive doped waste cooking oil biodiesel and its blends in compression ignition engine.
(2021) Maverengo, Hilton.; Inambao, Freddie Liswaniso.
South Africa, among the developing nations in sub-Saharan Africa lacks technologies for converting crude biooil into biodiesel to run fuel CI engines. The country has also struggled to identify a suitable feedstock that can be used for biodiesel production. This research was therefore aimed at analysing the suitability of mixed waste cooking oil (WCO) biodiesel doped with hybrid nano particles as a viable fuel for diesel engines. The utilization of WCO as feedstock for biodiesel is garnering attention since it does not impact on the food supply chain and provides a solution to the challenges associated with its disposal. Biodiesel acceptance has been hampered by three main issues. These are related to higher production costs linked to feedstock, higher nitrogen dioxide emissions, and a lack of economic evaluation of technologies incorporating different alcohols and catalysts. This research performed investigations to develop solutions to circumvent all these challenges. Regarding high feedstock cost, WCO was identified to present an easily available solution since it is acquired at a low cost and its usage helps to solve the disposal problem. Manufacture, assessment, and engine testing of biodiesel from WCO was conducted to evaluate its viability as a potential feedstock for biodiesel. From the derived results, WCO oil has higher oil yields and excellent fuel properties and therefore is a viable feedstock to create biodiesel. Transesterification, a biodiesel creation measure, was performed utilizing methanol and NaOH or KOH as catalysts. This feedstock showed some favourable engine exhaust emission behaviour, but on engine performance considerable shortfalls were noted when evaluated against fossil diesel (FD) fuels. Lower brake thermal efficiency and higher fuel consumption were noted when the neat fuel blends with fossil diesel were tested in two-cylinder compression ignition engines. Higher NOx emissions were also noted with WCO and its blends when evaluated against FD. Three options are available to dealt with the above problems, namely, engine modification, exhaust after-treatment, and fuel reformulation. Fuel reformulation is the most promising due to its easy implementation and cheaper cost. The researcher’s search for the most relevant solution resulted in identification of hybrid nanoparticles consisting of cerium oxide and aluminium oxide as the most appropriate solutions. WCO biodiesel and its blends were doped with nanoparticles and tested in two-cylinder compression ignition (CI) engines and results compared with those of FD. From the experimental analysis, addition of hybridized nano additives improved BTE by a maximum value of 6.22 % compared to FD fuel when evaluated against load. A maximum decrease in BSFC of 10.20 % was noted with hybrid nano fuel WCO20A50C50 compared to FD fuel. A significant reduction in NOX of 25.62 % was found compared to FD. CO, unburnt hydrocarbons (UBHC) and smoke opacity were reduced by 36.8 %, 27.8 % and 17.68 % respectively compared to FD. WCO20A50C50 produced the most superior characteristics of all the fuels tested in this research. To understand the combined impact of hybrid nanoparticles and other engine conditions on performance and emissions, design of experiments (DOE) using the response surface method (RSM) was performed to model and optimize WCO20 performance and emissions parameters. This was accomplished by utilizing a variable compression engine and selecting three variables, namely, hybrid nanoparticle blends (fuel blend), compression ratio (CR) and load as input parameters, while the analyzed responses were brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), nitrogen oxides (NOX), unburnt hydrocarbons (UBHC), carbon monoxide (CO) and smoke. The outcomes from this investigation showed that RSM is a viable technique for improvement of the parameters of biodiesel blends doped with nanoparticles in diesel engines. Considering the intricacy of biodiesel production measures, process development, technical assessment, and advancement of biodiesel according to the entire chain, is fundamental for improving its performance and increasing its global adoption. A detailed biodiesel process flow design was developed and economic assessment incorporating material performed. The designed plant is expected to produce 16.88 tons per annum. The cost of biodiesel was evaluated based on researched cost variables and plant data which resulted in a biodiesel production cost of ZAR10.10 per kg giving a total production cost of ZAR10,100.00 (US$673.33) per ton. A CaO ethanolysis catalysed process was shown to be the most appropriate process for WCO production – the reaction was faster and produced a high yield. South Africa, among the developing nations in sub-Saharan Africa, has a huge capacity to produce its own renewable fuels but at present there is an absence of localized and effective applicable techniques for converting crude bio-oil into biodiesel to run fuel CI engines. Therefore, the discoveries of the present doctoral study are important because they demonstrate that it is viable to convert WCO to biodiesel and that its properties can be enhanced with the addition of nano particles, thereby demonstrating that its performance is even better than that of FD. Furthermore, a more sustainable CaO catalysed ethanolysis, with superior yields and locally produced in comparison to methanolysis, has been effectively developed and evaluated, as per the objectives of the thesis.
Coupled heat and mass transfer in solar-powered liquid desiccant adiabatic dehumidifier and regenerator for air conditioning applications.
(2020) Oyieke, Andrew Young Apuko.; Inambao, Freddie Liswaniso.
Abstract available in PDF.
Design and performance analysis of hybrid photovoltaic-thermal grid connected system for residential application.
(2012) Mutombo, Ntumba Marc-Alain.; Inambao, Freddie Liswaniso.; Bright, Glen.
High output electrical energy is obtained from photovoltaic (PV) systems subject to high irradiance. However, at high irradiance, the efficiency of PV systems drops due to increase of the temperature of the systems. In order to improve the efficiency of photovoltaic systems, much effort has been spent on developing hybrid photovoltaic thermal (PVT) systems using water as a coolant to withdraw heat from solar modules. This research is focused on the study of the behavior of hybrid PVT collectors using rectangular channel profiles which provide a large surface for heat exchange between PV panels and thermal collectors unlike the circular channel profile used in conventional PV systems. In hybrid PVT systems, coolant water circulates in a closed circuit by means of the thermosyphon phenomenon and the heat from this water is extracted from a storage tank and can be used in hot water systems instead of an electric geyser. Numerical models of water velocity in channels due to the thermosyphon phenomenon and the temperature of solar modules was developed and a system was designed for modest Durban household demand. A simulation was run for specific summer and winter days comparing a conventional PV system and a hybrid PVT system. The results were very encouraging, and demonstrated that the equipment is capable of extending the PVT application potential in the domestic sector where more than 40% of electricity cost is heating water.
Design of a novel hydrokinetic turbine for ocean current power generation.
(2014) Cunden, Kumaresan.; Inambao, Freddie Liswaniso.
In a world with a growing need for energy, but also a growing need to decrease dependence on fossil fuel energy production, new methods of energy generation are required. The energy which exists in flowing rivers, ocean currents and various other artificial water channels is considered a viable option for a source of renewable power. Water energy harnessing systems are referred to as Hydrokinetic conversion systems. These types of systems are still in the infant stages of development as the main focus of renewable energy in recent years has been solar and wind energy harvesting. Research into ocean currents focusing on the Agulhas Current was conducted to be used as a basis for a Subsea Hydrokinetic system to be implemented off the coast of South Africa. The results obtained from Eskom’s Acoustic Doppler Current Profiler (ADCP) readings depict that the Agulhas current is a more than adequate source of renewable energy. The readings indicate that the Agulhas current varies from 0.3 m/s to 1.2 m/s throughout the year. A proposed Vertical-Axis Hydrokinetic turbine was designed to harness power from the Agulhas current. The design focuses on the selection of blade profile to exploit the lift force which is a result of the interaction with the flow medium. The blade’s helical structure is based on the relationship with the initial attack angle of the blade at a 0° azimuthal position based on the mathematical formulae derived by Gorlov. The study compares a toe-out angle which is not modelled by Gorlov. It was assumed that the turbine’s efficiency would be increased as long as the toe-out angle is within a specified range. Analytical and Computational Fluid Dynamic (CFD) simulations have been conducted on the designed hydrokinetic turbine. The analytical simulations implement double multiple stream tube models which have been used for predecessors of the vertical axis helical turbine. The analytical model was performed in QBlade which is software that implements the double multiple streamtube theory. The CFD model was conducted within Star CCM+TM which included complex vortex interaction and interference with the turbine. Results obtained from the analytical model show that the turbine with a toe-out blade pitch had a slightly lower performance coefficient than the turbine with no blade pitch within the range of 1° to 2°. The results from the CFD simulations and the analytical modelling were in good agreement. The results obtained for the performance of the turbine for toe-out blade pitch from the analytical and CFD modelling were 50% and 52%, respectively. The results are in line with that of simulations and testing of similar type turbines conducted by previous researchers. Comparisons from the effect of toe-out angle on the turbine’s performance proved that the turbine does not experience an increase in efficiency; however, the torque fluctuations decreased for increasing blade pitch. The toe out angle reduced the amount of torque fluctuations on the turbine rotor which provides fewer fluctuations to the coupled generator.
Design of an improved solar powered water desalination plant.
(2020) Singh, Devesh.; Inambao, Freddie Liswaniso.
Abstract available in PDF.
Design, modeling and optimization of a seawater reverse osmosis desalination plant.
(2021) Ncube, Randy.; Inambao, Freddie Liswaniso.
Potable water is one of the major needs for human, animals and plant survival. But recently, due to the growth in population and industrialization, fresh water shortage has escalated to alarming levels particularly in the Middle East and Africa. South Africa has not been spared in this predicament. Recently, Cape-town and its surrounding areas have been hard hit by water shortages and in one of the years, the region almost got to day zero, where all water sources were about to run dry, yet the region is surrounded by vast amounts of sea water. Research and development of several methods to mitigate this problem is still ongoing. Desalination of seawater is one of the several ways which have been used to ease this problem, and Reverse Osmosis (RO) is generally taking over as the preferred technique of desalination because of its generally higher efficiency and better quality of water produced using generally lower energy. Research has also shown that the limitations and concerns of using RO technique on water productivity are membrane fouling and high energy consumption in these plants. Design, modeling and optimization using modelling and simulation softwares and experiments on seawater reverse osmosis (SWRO) desalination plant is one of the ways in which this water shortage crisis may be alleviated. This dissertation seeks to attend to the limitations of the available plants in use through experimentation, coming up with mathematical models and simulations to increase throughput and efficiency of the system. Theoretical data analysis and membrane modeling of a SWRO desalination unit was done on the design and undertaken using Hydranautics Nitto Group Company powered Integrated Membrane Solutions Design (IMSDesign) software, a membrane modeling software that allows users to design a reverse osmosis (RO) system based on Hydranautics membranes. The experiments were done on the Victoria and Alfred (V&A) Waterfront desalination unit, a seawater desalination plant located along the Atlantic Ocean coastal city of Capetown, South Africa. Extracted data from experiments was collected and statistically analyzed using Microsoft excel and different relationships of parameters were plotted. Some of the design input and output parameters that were studied using include feed and permeate TDS, pressure, temperature, pH, energy consumption and conductivity. The effects of different fee parameters were compared against their permeate variables in the month of November 2018, and several relationships and correlations were plotted. Experimental data showed that an increase in feed temperature resulted in a decrease in permeate TDS, whereas and increase in feed pressure resulted in a general increase in permeate TDS. Finding the optimum compromise between the two input variables was done and optimum values were found. Energy efficiency and reducing energy consumption of the plant while not compromising on product quality is also one of the parameters that were studied and the relationships between feed TDS, feed temperature, feed pressure and feed pH against energy consumption were modelled. Modeling and simulation using ROSA and IMSDesign softwares was undertaken and several equations and correlations of specific energy and input temperature, feed temperature and permeate TDS, feed TDs and permeate TDS were produced. Optimization of the V & A desalination plant was performed using experimental data extracted from the plant and some assumed data. Simulation and optimization was accomplished using Water Application Value Engine simulation software and improvements in specific energy consumption, permeate TDS and permeate productivity were observed.
Design, modelling and optimisation of an isolated small hydropower plant using pumped storage hydropower and control techniques.
(2015) Ilupeju, Samuel Ayanrohunmu Olusegun.; Inambao, Freddie Liswaniso.
Pumped Storage Hydropower (PSH) has proved to be a reliable power generation technology, especially in cases of emergency peak power demand. It is best utilised in areas where the availability of water is a challenge because it allows water retention and reuse using the pump back mechanism instead of the water being discharged to continue its course. A pumped storage hydropower system consists of two reservoirs, one higher in elevation than the other lower, the turbine house (power station) and pumping plant between the two reservoirs. During off-peak periods, excess electricity which is cheap pumps water from the lower to the upper reservoir because power demand is low. The stored energy is released to run back into the lower reservoir through the turbines to generate electricity in peak demand period, converting the stored potential energy into electricity at a higher economic value. South Africa is among the highest emitters of carbon dioxide in the world, with more than 75% of primary energy requirement from fossil fuels. Specifically South Africa is ranked 12th in the world in terms of top emitters of carbon dioxide, exposing its citizens to risks associated with this emission [1]. Therefore there is an urgent need to protect lives by technically reducing release of the poisonous gases through reducing fossil fuel dependency. Renewable Energy (RE), which is abundant and sustainable, can be quickly implemented, offer many work opportunities and have a much lower impact on the environment. With over 8 000 potential small Hydropower sites identified in Eastern Cape and KwaZulu Natal (KZN) Provinces, generation can improve. The system proposed is the design, optimisation and integration of a control system to a standalone micro hydropower hybrid. The conventional hydropower plant, which is a primary electricity source, allocates power to pump from the lower reservoir to the upper at off-peak periods when consumption and price of electricity is low at regulated flow. Various calculations were derived to compute the primary design parameters (flow, head and system efficiencies) with the other inputs. Matlab Simulink was engaged to describe the interaction between these variables and to vary parameters for optimum output, especially in reducing pumping mode power input for maximum pumped storage hydropower plant generation. Different categories of small hydropower plant sizes can be determined and analysed using this model which will give suitable results. Though the value of generation output from the PSH is small compared to input pump power it is able to compensate for peak load demand. The control system is introduced using Flowcode software to automate every technical process to ensure optimum system performance. The automation considers, time of the day, the volume of the upper reservoir and the available pumping power to efficiently manage the hydropower plant model. With the introduction of this generation technique, the results have shown that generation of more electricity at peak time when the price of selling the electricity is very high can be easily accomplished. The control effectively minimises electricity losses, breakdown of equipment, and ensures availability of resource at the exact time of demand. With this design, existing hydro plants may be upgraded for optimum generation without posing any negative effect on the environment in the way that coal fired plants do. Other renewable energy sources may be exploited in pumping activities to reduce the effect of pumping to the upper reservoir on the conventional hydropower plant.
Designing a photovoltaic-microbial fuel cell (pv-mfc) renewable hybrid system based on public-private partnership and other South Africa’s policies: a case study Umhlathuze municipality.
(2021) Nhleko, Melusi Velolwenkosi.; Inambao, Freddie Liswaniso.
Abstract available in PDF.
Development and fabrication of functionally graded aluminium metal matrix composite for automobile component applications.
(2021) Owoputi, Adefemi Oluwaniyi.; Inambao, Freddie Liswaniso.; Ebhota, Williams Saturday.
In recent times, interest in aluminium matrix composites (AMCs) have garnered traction over conventional aluminium alloys as the material of choice in the manufacturing of components for various engineering applications. Engineering components developed from single-element material are increasingly less favored over materials engineered from two or more elements. The rise in the demand for a multifunctional engineering material to exhibit opposing yet complementary engineering properties at different spatial positions within the material due to functionality requirements, has birthed several innovative fabrication processes. This study focuses on the development and fabrication of functionally graded aluminiummetal matrix composite (FGAMMC) through the liquid metallurgy route for proposed automobile component production. Industrially produced A356 aluminium alloy and silicon carbide powders (Al-SiC) was adopted as the base matrix and reinforcement materials for the fabrication of the metal matrix composites. Centrifugal casting technique was used to fabricate seven samples of Al-SiC functionally graded aluminium metal matrix composites with varied reinforcements particle size and weight percent addition. Samples A, B, and C contained 1 wt.%, 3 wt.%, and 5 wt.% of SiC of size 7 μm reinforcement, respectively, while samples E, F, and G had 1 wt.%, 3 wt.%, and 5 wt.% of SiC of size 15 μm reinforcement respectively. Sample D with no reinforcement additions served as the control sample for the experiment. Microstructural characterization showing the elemental composition and reinforcement distribution of silicon carbide particles within the matrix of the cast composite was carried out using optical microscopy (OM), optical emission spectroscopy (OES), energy dispersion xray (EDX), and scanning electron microscopy (SEM). The influence of SiCp on the mechanical, wear behavior and thermal properties of the cast aluminium composites were determined by subjecting the cast samples to mechanical, tribological, and thermal tests. Sample C with 5 wt.% and 7 μm of SiC particle reinforcement recorded improved hardness,compressive strength, Young's modulus, shear strength, and shear modulus of 112.7 HV0 1, 3107 MPa, 6.39 GPa, 14.4 GPa, and 9.29 GPa, respectively. Tribological analysis show an increase in the cast composites' wear resistance and frictional coefficient proportional to the frequency of contact between the counterface ball of the tribometer and the dispersed SiC reinforcements in the composites' matrices. Thermogravimetric analysis showed the weight loss and heat flow rates exhibited by the cast samples as the temperature was increased from 25 °C to 1000 °C in an Argon environment. Although negligible weight loss was recorded for all the cast composites within the experimental temperature boundary, sample C with 7 𝜇m
Development of neuro-fuzzy strategies for prediction and management of hybrid PV-PEMFC-battery systems.
(2017) Mutombo, Ntumba Marc-Alain.; Inambao, Freddie Liswaniso.; Tiako, Remy.
Abstract available in PDF file.
Development of thermal energy storage and cooker module for the integrated solar energy project.
(2008) Sulaiman, Abdulsalam S. A.; Inambao, Freddie Liswaniso.; Reinhardt, Gavin Leigh.
Large percentages of the South African population have no access to grid power and are located at distances that make provision for such facility uneconomical. Also traditional fuels are under pressure. Most areas in South Africa receive 300 days of sunshine per year. The proposed solar system addresses the needs of such communities. A solar thermal energy storage system utilizing phase change material has been proposed that can overcome the time mismatch between solar availability and demand. The system consists of two types of thermal heat storage. The latent heat storage used Phase Change Materials (PCM) which melts at a sufficiently high temperature for cooking a variety of food types. By choosing a suitable PCM to take advantage of the latent heat absorbed during phase changes. Heat losses from both the latent heat storage and condenser are captured in the surrounding sensible heat store. The objective of this project to develop a prototype modules which together as a system could provide the essential domestic power requirements of the target groups. This includes power for cooking, hot water and in addition a limited electrical power supply for the system itself as well as for other minor loads.
Double shrouded horizontal axis wind turbine.
(2013) Johri, Abhishek.; Inambao, Freddie Liswaniso.
This research study deals with the design and optimization of a Shrouded Horizontal Axis Wind Turbine which is an emerging system in the field of renewable energy resources. The literature review shows that several authors have studied single shrouded horizontal axis wind turbines and many applications are in existence, but no development has been done in the field of double shrouded horizontal axis wind turbines. South Africa’s surging growth in electricity consumption requires development of this kind of wind turbine which can be implemented at both domestic and commercial levels. This research emphasis is on the development of a second shroud overlaying the existing shroud of a wind turbine. The research focuses on the development of a double shrouded horizontal axis wind turbine using a different type of NACA airfoil for the shroud and the blade in order to optimize the results. The objective of this research was to design and develop a shroud design with flanged ends which could operate a horizontal axis wind turbine at very low wind speeds. The effect of the double shroud on the wind speed is analyzed and optimized by simulation using different airfoil designs and profiles. The maximum wind speed increased 2.004 times at low wind speeds ranging from 2m/s to 7m/s and increased by 2.162 times for the high wind speeds ranging from 8m/s to 13m/s with the selection of an appropriate airfoil for the outer and inner shrouds. This shroud design is suitable for those areas where the wind speed is not very high due to urbanization and mega structures obstructing the wind flow hence reducing the wind speed. Also it is suitable for use in farm lands, rural areas, remote telecommunication stations etc. where it can stand alone in fulfilling energy requirements. In this study, Computational Fluid Analysis and optimization of the design were carried out using highly efficient CFD software, namely, Star CCm+. From the study we concluded that replacement of a single shroud with a double shroud provides a surge in energy efficiency of wind turbines of the same class.
Drying of faecal sludge from ventilated-improved pit latrines( VIP latrines) using solar thermal energy.
(2019) Mugauri, Tendayi Ronald.; Inambao, Freddie Liswaniso.; Stringel, Santiago Septien.; Singh, Anusha.
Ventilated improved pit (VIP) latrines are a basic form of sanitation in South Africa. The main challenge facing the application of VIP latrines is the gradual fill up of the pit due to usage. A sustainable way of treating FS remains from sanitation systems is by using solar energy. This project is focused on the characterisation of solar drying for FS treatment. A solar thermobalance was designed and constructed to investigate the solar and open-air sun drying of FS. Mass variations, temperature, humidity and solar irradiance properties were monitored during the drying process. The drying experiments for solar drying were conducted with the following variables: weather conditions; air temperature; airflow velocity; sample thickness and surface area. The experiments were carried out in October and November 2017. The drying kinetics were observed to be influenced by the weather conditions, air temperature and air flow rate, but the sample thickness and surface area of the sample did not have any significant effect on the drying rate, under the explored conditions. Solar drying recorded drying rates which averaged 0.892 kg/h.m2 across the investigated parameters and were comprised between 0.622 to 1.135 kg/h.m2, whereas open-air drying averaged a drying rate of 0.479 kg/h.m2, varying in the range 0.686 - 0.078 kg/h.m2. The faecal sludge was found to dry best under sunny conditions, 30 oC air temperature and 0.5 m/s air flowrate. Qualitative and quantitative analysis was also conducted to characterise the influence of solar and open-air sun drying on the physico-chemical characteristics of faecal sludge. Density, shrinkage, thermal conductivity and heat capacity showed great dependence on the final moisture content which depended on the employed drying conditions. Crusting and cracking of the samples were observed to occur, and their intensity depended on the investigated conditions and were suspected to affect the drying rate in specific experimental conditions. This is shown in the lower drying rates for 1.0 m/s air flow rate and 60 oC air temperature. Odour strength increased with lower final moisture content. In summary, the application of solar energy for drying proved to be a feasible option for the treatment of FS. Drying in a solar thermal system with controlled conditions of air properties will consist in an improvement on the current sludge dehydration practices, such as the drying beds (open-air drying).
The effects of exhaust gas recirculation (EGR) on the performance of diesel engine.
(2018) Maroa, Samwel Semakula.; Inambao, Freddie Liswaniso.
The aim of this work was to study the effects of EGR on the performance of a diesel engine using waste plastic pyrolysis oil (WPPO) and conventional diesel (CD). WPPO was developed through the pyrolysis extraction method. The blends were made up of WPPO and conventional diesel mixed in the ratios of WPPO10, WPPO20, WPPO30, WPPO40 and WPPO100. The EGR % flow rate chosen was 0 % to 30 % graduated in intervals of 5 %. The lower blend ratios of WPPO10 and WPPO20 showed lower values of brake specific fuel consumption (BSFC) compared to conventional diesel values and the high blend ratio of WPPO100. The brake thermal energy (BTE) showed increased values for lower blend ratios of WPPO10 and WPPO20 of 8.35 % and 8.15 % respectively with application of an EGR % flow rate of 15 % compared to high blend ratios of WPPO30, WPPO40 and WPPO100. The application of EGR % flow rate was observed to cause no significant change in the engine brake power (BP) for all the test fuels used. The application of EGR % flow rate in increasing rates reduced exhaust gas temperature (EGT), with conventional diesel reporting 440 ⁰C at 5 % EGR flow rate and 340 ⁰C being the lowest at 30 % EGR flow rate. The application of EGR % flow rate reduced the amount of hydrocarbon emissions emitted by the applied test fuels across the board. At EGR flows rate of 5 %, 10 %, 15 %, 20 %, 25 % and 30 %, conventional diesel had 43 ppm, 57 ppm, 70 ppm, 82 ppm and 85 ppm respectively. As the blend ratio increased with increased EGR % flow rate there was an increased rate of NOX emissions. At 20 % EGR flow rate, blends WPPO10, WPPO2O, WPPO30, WPPO40 and WPPO100 had 591ppm, 645 ppm, 750 ppm, 778 ppm and 851 ppm respectively compared to at the 10 % EGR flow rate where their values were 830 ppm, 971 ppm, 1031 ppm, 1151 ppm and 1116 ppm respectively. There was a significant continuous and marginal increase in the percentage of carbon emissions by volume as the load increased across all the test fuels irrespective of the EGR % flow rate. At 80 % engine load the value for WPPOB100 was 2.0 % up from 1.65 % by volume at part engine load, while the value of conventional diesel was 4.1 % at 80 % engine load compared to 2.95 % by volume at part engine load. The application of EGR % flow rate increased the carbon dioxide emission exponentially by almost doubling the values. At 10 % EGR flow rate the value of conventional diesel was 3.85 % compared to WPPOB100 at 6.25 %, WPPOB10 at 4.75 %, WPPOB20 at 4.25 %, WPPOB30 at 3.95 %, and WPPOB40 at 6.65 %.
Effects of pyrolyzed municipal solid waste feedstocks as energy sources for non-road diesel engine, combustion, performance and emissions characteristics using biodiesel blended ratios.
(2021) Maroa, Samwel Semakula.; Inambao, Freddie Liswaniso.
Biodiesel oil blending is not a new concept in the study of biofuels and production. Blending is a chemical process of two or more different feedstocks comingled in varying proportions in the production of a new oil or fuel blend possessing different physico-chemical properties. Since fuel properties and the physico-chemical configuration of each feedstock vary from source to source, blending improves and enhances these properties. Therefore, the combination of different feedstocks enhances and improves properties of the initial parent feedstock, by adapting to improved and high-quality attributes. Worldwide, the sources of biodiesel production has been centred on edible and non-edible plants such as sunflower, canola, soybean, moringa, Jatropha, and so on. However, in the recent past, there has been a renewed shift into biomass and other recycled waste sources for biodiesel production and utilization. Waste to energy is a critical area of research and study in this present work as it intends to fill in these gaps by emphasising the shift to biodiesel production from non-plant-based sources. This shift will increase food security by discouraging the contribution of commercial farming for the production of biodiesel. This work contributes to improving environmental protection by reducing pollution from municipal solid waste found in landfills and other waste management sites. Waste resources such as waste cooking oil, waste engine oil, waste tyre oil and waste plastic oil converted into energy provide many alternatives in reducing wastage. By promoting use of these resources, this study aims at increasing environmental awareness and sustainability by using waste as an energy resource. This focus will open up socio-economic opportunities in recycling besides the academic and research impacts. By employing blending strategies using these waste feedstocks (engine oil, cooking oil, plastic oil and waste tyre oil using pyrolysis thermal processes), the study will improve the initial poor chemical properties which will confer improved engine performance with emissions reduction especially those dealing with sulfur and other contaminants from municipal solid waste streams. The production of pyrolyzed municipal solid waste (MSW) oil will be ex-situ and in-situ (the former means after production while the later means before production of biodiesel). This research work will assist in determining standard procedures and sequencing to obtain working ratios of the blending processes and techniques of biodiesel production.
Energy efficiency in motor vehicle assembly plant : a case study of a vehicle assembly plant in Kenya.
(2014) Kiarie, Grace Wanjiru.; Inambao, Freddie Liswaniso.
Energy is defined as the capacity to do work and comes in various forms such as motion, heat, light, electrical, chemical, nuclear, and gravitational. There are two forms of energy: primary energy which is extracted or captured directly from the environment and secondary energy which is converted from primary energy in the form of electricity. Energy efficiency means a physical ratio of output and input of a system. Efficiency refers to valuable work obtained from a process or system when related to the total energy input; it is, therefore, an indication of the performance of a device in energy use terms. The industrial sector is the largest consumer of energy globally and this is the case too in Kenya. The major forms of energy used in Kenyan industries are electricity, diesel oil, compressed air, steam and solar energy. Energy in industries is used for various activities such as heating and cooling, lighting, processing, manufacturing, air conditioning and assembly; a lot of energy is lost during these operations due to poor maintenance of machines, poor management, misuse and mishandling of equipment, bad attitude and lack of knowledge among workers. In vehicle assembly plants energy is used in heating, welding, assembly, lighting, painting and office work. The major types of energy used in vehicle assembly plant are compressed air, electricity, industrial oil and diesel. These industry sectors face a lot of challenges because many cars used in Kenya are imported from Japan because the locally assembled cars are more expensive although they are durable. Among the factors which make them expensive includes raw material, payment of salaries and wages, process of assembly, and heavy payment of bills. The major bills in many industries after payment of salaries are energy bills for electricity, diesel and industrial oil. The cost of electricity and diesel in Kenya is escalating due to high demand and low supply, thus making locally made items more expensive than imported ones. Industries in Kenya are struggling to adopt new manufacturing processes and designs to cut down operating costs and improve the quality of products to meet the competitive demand. The same case applies to the automobile assembly industry; they are trying to come up with new designs and models to increase sales, but are forgetting to pay attention to methods of reducing energy costs. Energy efficiency in many industries remains silent and this is because the issue of balancing the operation costs and investing in energy efficiency is only remembered when the bills climb high. Many researches have concentrated on improving the design of assembly lines, changeover of machines and equipment to improve the system, but little has been researched regarding the energy used during the assembly of the vehicles. As manufacturers face an increasingly competitive environment, energy efficiency management can provide a means to create a good reputation for the company, hence increase its sales, but also a method for reducing energy costs. The aim of the present study is to contribute to improvement in energy efficiency in automotive industries by estimating the amount of energy used and lost by various equipment, identifying the barriers to energy efficiency and the driving forces inhibiting or preventing implementation of energy efficiency measures, and providing recommendations on useful energy efficiency opportunities and maintenance measures. The study was carried out in one of the four major automotive assembly plants in Kenya. Questionnaires, observation, measurements, oral interviews and audits were used to collect data. From the analysis, welding machines and fans are the major consumers of electrical energy with an approximate of 45 % and 17 % respectively. Burners and generators are the major consumers of oil with 73 % and 15 % respectively. From observation, the use of aged equipment, lack of training and ignorance among employees are the major causes of energy loss. Idling of machines, leaks, dust and faulty lamps are the major source of energy loss in the plant. It is recommended to clean, switch off, train workers and do proper maintenance. The research study was able to estimate the amount of energy used and lost in various machines and equipment and various recommendations were given. It was concluded that, to improve on energy management in this motor vehicle assembly plant, energy management should be treated equally in importance with production and sales.
Energy efficiency in the South African cement finishing plant: drivers, barriers and improvement.
(2017) Ige, Oluwafemi Ezekiel.; Inambao, Freddie Liswaniso.; Ilupeju, Samuel Ayanrohunmu Olusegun.
The cement production is an energy demanding industry that requires a high degree of attention regarding energy use in South Africa. Within the last decade, South Africa has faced a shortage of electricity supply, because the maximum electricity demand has invaded the net maximum capacity and the margin of the reserve storage is reduced. This study investigates a range of barriers, drivers and opportunities to improve the energy performance of a cement plant in South Africa, in order to provide the information necessary to sustain energy efficiency improvement efforts within the cement industry. Energy efficiency can be defined as a cost-effective method of reducing cost of energy and greenhouse gas (GHG) emissions, resulting in extra quality of production and increased environmental benefits. Energy efficiency is widely accepted as an effective tool for improving the global energy situation. Prudent energy use by industry is a solution for a sustainable environment and industrial development. Energy efficiency and energy management cost-effective use measures provide industry with successful ways of achieving economic and social dividends in order to reduce harmful environmental impact of energy usage. Unfortunately, industries from less developed countries are slow in adopting energy efficiency and management measures; therefore, they lack the paybacks of energy efficiency implementation. This work aims to increase awareness of the need for development of South Africa’s industrial energy efficiency and industrial management policies by exploring the current energy efficiency and management practices of one of the oldest cement plants in South Africa. The study also included a survey of barriers and drivers for implementing energy efficiency measures in cement finishing mill plant; and clarified the basis for the adoption and non-adoption of cost-saving energy efficiency in South Africa industries. This research was an exploratory type of the study, conducted by means of semi-structured interviews. The survey was conducted in two parts. In the first part, asked about the plant’s energy management policies that in place. In the second part, asked the respondent to complete a prepared questionnaire that cover all aspects of the study. The results show that poor energy management within the plant and low energy efficiency measures lead to an energy efficiency gap in the plant. Furthermore, it shows that important barriers that hinder the implementation of cost-effective measures within the plant are mainly due to economic related barriers to rational behavior, which are associated with the lack of plant energy efficiency due to the organization structure. The study also found that organizational benefits related to “environmental company profile” and “environmental management systems” followed by economic benefits associated to “cost reductions resulting from lower energy use” are the most high-ranking drivers of energy efficiency measures within the plant.
Energy efficiency opportunities for pulp and paper industry in South Africa: barriers, drivers and technical opportunities.
(2017) Maverengo, Hilton.; Inambao, Freddie Liswaniso.; Ilupeju, Samuel Ayanrohunmu Olusegun.
Abstract available in PDF file.