Biomass is a form of renewable and sustainable energy source with the highest potential to contri... more Biomass is a form of renewable and sustainable energy source with the highest potential to contribute to the energy needs of modern society for both the developed and developing countries. However, its usage in form of biofuels is still in the preliminary stage. There is a ...
This paper treats exergy analysis of rice husk at various loading rates of 1 kg, 1.5 kg and 2 kg ... more This paper treats exergy analysis of rice husk at various loading rates of 1 kg, 1.5 kg and 2 kg of feedstock, using a batch type, fixed-bed gasifier, equipped with a gas filtering system and between the operating temperatures of 690 K and 1100 K, operated for the whole year. Exergy analysis is a thermodynamic technique which uses conservation of mass and energy principles to design thermal systems with maximum efficiency and it is based on First and Second law of thermodynamics. Formulas from literature and previous researches as well as Microsoft Excel 2007 were used to make calculations and graphically interpret the results. The exergoeconomic analysis is based on location specific and national data collected from official sources. A MATLAB based hybrid model developed from a combination of other studies is used to generate the exergoeconomic analysis results. Methane was found with the highest total exergies where values of exergies were varying between 1110126 kJ and 1066279 kJ...
This study presents the design and testing of a waste-to-energy plant by incineration of small sc... more This study presents the design and testing of a waste-to-energy plant by incineration of small scale municipal solid waste to produce steam for electricity production. The average total waste generated within the study area was found to be 55,800kg/day, with an estimated calorific value of 13,958kJ/kg. The waste samples were collected, dried, shredded and weighed in order to reduce the moisture content to the acceptable minimum and decreases the surface area of the sample that will allow easier penetration of heat. The incinerator was designed using CATIA-5 software. The key performance indices of the developed plant are maximum furnace temperature, residence time, mass flow rate, steam pressures and amount of steam generated keeping the mass of waste constant per test but varying the air flow. The moving grate is inclined at an angle of 12° while the volume of the incineration combustion chamber was calculated to be 0.267m3. 150kg of small scale waste was fed into the combustion ch...
This paper treats the design of a small pedal operated briquette press to produce three (3) briqu... more This paper treats the design of a small pedal operated briquette press to produce three (3) briquettes of about 220mm length at a time using agricultural and wood wastes . The small light weight fuel briquette machine was successfully constructed using locally available materials and tested. The machine was able to produce 120 briquettes per hour and it will reduce the cutting down of trees for fuel-wood purposes, thereby preventing deforestation and erosion. Shrinkages were noticed and the final size of the briquette upon drying was observed to be 210 mm x 80 mm x 67 mm. The average true and apparent densities were also found to be 338.2 kg/m<sup>3</sup> and 263.04 kg/m<sup>3</sup> respectively. The effect of the binder content on the combustion potentials of the briquette needs to be investigated further. The product (briquette) obtained from the machine can be used as alternate to fuel-wood in domestic cooking and small-scale industries. The machine will a...
Biomass is a form of renewable and sustainable energy source with the highest potential to contri... more Biomass is a form of renewable and sustainable energy source with the highest potential to contribute to the energy needs of modern society for both the developed and developing countries. However, its usage in form of biofuels is still in the preliminary stage. There is a need to identify a suitable biofuel in terms of availability, which can provide high-energy output to supplement the rapidly depleting fossil fuels. Animal wastes are rich sources of energy and they are abundantly found in the semiarid regions. The energy from the waste material is extracted by anaerobic digestion of the organic matter by bacteria. This paper covers the design, cost analysis, construction and testing of a family size biogas plant for use under local conditions, and safety features for the prospect of large biogas production in semi arid regions. Plants were constructed and tests were conducted at the workshop of the University of Maiduguri in Nigeria; and the gas produced was found to be burning c...
Arid Zone Journal of Engineering, Technology and Environment, 2017
This paper presents a numerical simulation of air velocity and air temperature distribution in an... more This paper presents a numerical simulation of air velocity and air temperature distribution in an office room of Computer Engineering Department of University of Maiduguri which is naturally ventilated. The office room under investigation with the dimension 5 m × 5 m × 4 m has a door in the East direction, and two windows, one in the East direction and the other in the South direction. For cost effectiveness, numerical solutions of steady-state airflow and heat transfer were done using a complete two-dimensional model. The results showed that the windows and the door could not undertake indoor heat load that can make the occupants to be thermally comfortable. In activity area where people sit and stand, the air velocity is moderate, this is about 0.98 m/s on the average. In addition, the temperature in this area is relatively high of about 302 K (29 °C) on the average. Based on the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) standard for comfor...
ATBU Journal of Science, Technology and Education, 2016
Thermal comfort has a great influence on the productivity and satisfaction of indoor building occ... more Thermal comfort has a great influence on the productivity and satisfaction of indoor building occupants. The exposure to excessive heat or cold during work may cause discomfort and contributed to low productivity among workers. Maiduguri, Borno State is known with its hot and cold condition during summer and hammattan weather respectively. Unimaid Engineering workshop had exposed to excessive temperature during summer and excessive cold during hammattan while working. The study investigates the thermal comfort level experienced by students at Unimaid Engineering workshop during hammattan season. The study had been conducted at the machining section, the foundry unit, fabrication section and engine section. The environmental factors examined were the relative humidity (%), air temperature and air velocity of the workshop area. The environmental factors were measured using Luton apparatus, which is capable of measuring simultaneously those mentioned environmental factors. Then thermal...
ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ANGLAIS The paper focused on th... more ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ANGLAIS The paper focused on the mathematical modellin g and simulation of low calorific value municipal solid waste incineration in semiarid region. Municipal solid wastes were collected and analysed; from which wood samples were taken and incinerated using a prototype incinerator. A mathematical model, based on Fourier series (FS) and finite elements method (FEM) was developed, ran and validated using experimental and literature data. Critical minimum volume of 4.93 m 3 or about 6 % of the total volume of the incinerator would be needed at 20% moisture content refuse and a critical maximum volume of 51.10 m 3 or 69.21% of the total volume, would be needed at 50% moisture content. The ignition time and the time at which the combustion becomes self-sustaining are greatly influenced by the moisture content. Critical drying temperature was found to be 711.44 K. The grid size had little or no effect on the simulated resu...
Arid Zone Journal of Engineering, Technology and Environment, 2017
The study presents an application of the artificial neural network model using the back propagati... more The study presents an application of the artificial neural network model using the back propagation learning algorithm to predict the actual calorific value of the municipal solid waste in major cities of the northern part of Nigeria, with high population densities and intense industrial activities. These cities are: Kano, Damaturu, Dutse, Bauchi, Birnin Kebbi, Gusau, Maiduguri, Katsina and Sokoto. Experimental data of the energy content and the physical characterization of the municipal solid waste serve as the input parameter in nature of wood, grass, metal, plastic, food remnants, leaves, glass and paper. Comparative studies were made by using the developed model, the experimental results and a correlation which was earlier developed by the authors to predict the energy content. While predicting the actual calorific value, the maximum error was 0.94% for the artificial neural network model and 5.20% by the statistical correlation. The network with eight neurons and an R2 = 0.9688...
ENGLISH/ANGLAIS] Affiliations: 1 Department of Mechanical Engineering, University of Maiduguri, P... more ENGLISH/ANGLAIS] Affiliations: 1 Department of Mechanical Engineering, University of Maiduguri, PMB: 1069, Borno State, NIGERIA 2 National Agency for Science and Engineering Infrastructure (NASENI), Abuja, NIGERIA 3 Department of Mechanical Engineering, Ramat Polytechnic, PMB: 1070, Maiduguri; Borno State, NIGERIA Address for Correspondence/ Adresse pour la Correspondance: [email protected] Accepted/Accepté: September, 2012 Citation: Oumarou MB, Dauda M, Abdulrahim AT, Abubakar AB. Municipal Solid Waste Generation, Recovery and Recycling: a Case Study. World Journal of Engineering and Pure and Applied Science 2012;2(5):143-7. The paper presents a case study focused on waste generation, material recovery, and the recycling potential of municipal solid waste in Maiduguri, Nigeria. The municipal solid waste (MSW) generation was estimated using a fuzzy logic based mathematical model followed by a collection scenario thought of, adopted and tested within two planned residential areas; ...
In a hot climate like Maiduguri, one of the conventional approaches for providing comfortable env... more In a hot climate like Maiduguri, one of the conventional approaches for providing comfortable environment is the use of natural ventilation. In some cases, this strategy does provide the suitable thermal environment in a large space building such as the mosque. This study evaluated the thermal comfort of a naturally ventilated large space building, the university of Maiduguri central mosque in Maiduguri, Borno state during different times of daily prayers. The field study was conducted in 16th December 2015 (harmattan season) and April 2016 (hot season) during subuh, zuhr, Asri, Magrib and Ishai prayer times. During these days, the objective measurement using LUTRON ABH-4224 Cup Anemometer instrument and subjective assessment using questionnaire were accomplished. The objective parameters measured were air temperature, relative humidity and air velocity and the subjective responses concern the thermal condition of the respondents. Through linear regression analysis, Predictive Mean ...
R12 has been replaced with R134a due to its zero ozone depletion potential (ODP) in refrigeration... more R12 has been replaced with R134a due to its zero ozone depletion potential (ODP) in refrigeration system. The material compatibility and safety of R134a in refrigeration units as made it to be more attractive. However, R134a is to be phased out due to its high Global Warming Potential (GWP) and immiscible nature with conventional mineral oil. This paper presents the theoretical assessment of energy performance of a large capacity freezer using R134a and R430A as alternative refrigerant. In assessing the performance, three different condensing temperatures, that is, 40, 50 and 60oC and evaporator temperature between -30 and -18oC were chosen. The thermodynamic and thermophysical properties, namely, vapor pressure, latent heat, viscosity and density, using R134a and R430A refrigerants were compared. The performance parameters, such as coefficient of performance (COP), compressor power consumption (CPC) and Pressure ratio (Pr) were also compared. The results showed similarity in the va...
Arid Zone Journal of Engineering, Technology and Environment, 2015
This study investigates the performance of a micro Horizontal Axis Wind Turbine (HAWT) blade usin... more This study investigates the performance of a micro Horizontal Axis Wind Turbine (HAWT) blade using Computational Fluid Dynamics (CFD). The 1.5 m long micro HAWT blade was designed using the Blade Element Momentum Theory (BEM). Parameters such as the chord length lift force, drag force, tip speed ratio, solidity, coefficient of performance, angle of attack, wind relative angle, Reynolds number, efficiency, axial and induction factors were determined. Based on the design parameters the micro blade was created, meshed and boundary conditions identified in a 2D pre-processor Gambit interface. The meshed blade was exported to Fluent where it was processed and analyzed based on the identified boundary condition. The blade was simulated based on Maiduguri environment which has a recorded average wind speed of 3.89 m/s and the result showed that the maximum extractable power was 142.66 watts at a wind relative velocity of 4.8m/s when the blade was at 8o angle of attack and 3 x 106 Reynolds ...
The paper treats the design of a municipal solid waste incinerator suited to the semiarid regions... more The paper treats the design of a municipal solid waste incinerator suited to the semiarid regions with northern Nigeria and Niger Republic in West Africa as the study area. Proximate and ultimate analyses results from the solid waste were used as basis for calculations, using standard formulas and correlations. The calorific value of the solid waste samples in the study area is not high enough to sustain an incineration process and it ranges from 5.024 MJ/kg to 5.867 MJ/kg. For these types of low calorific value fuels, the parallel flow concept was found to be the appropriate type of incinerator. The solid waste to be fed in the incinerator needs to be mixed with 50% of supplementary fuel in the form of readily available bagasse to make it up to the required lower calorific value. Major characteristics of the designed municipal solid waste incinerator were: total volume of incinerator chamber: 82.5 m 3 , length of the incinerator bed: 11m; width of the incinerator bed: 3m and height...
Arid Zone Journal of Engineering, Technology and Environment, 2017
This study characterized and analysed the constituents of the leachates from four uncontrolled an... more This study characterized and analysed the constituents of the leachates from four uncontrolled and unlined waste dumpsites in Maiduguri, North eastern Nigeria. The leachate samples were carefully collected from waste dumpsites without any conventional collection equipment and transferred to the laboratory for analysis. The ionic concentration, pH, electrical conductivity (EC), and total dissolved solids (TDS) were determined using a conductivity meter, potassium and sodium by photometer; chlorine and calcium by titration method, BOD was computed from dissolved oxygen as determined by Winkler’s method and the UNICAM 969 Atomic Absorption Spectrophotometer was used to measure the cation and anion concentrations. The pH and TDS values ranged between 8.19 to 11.32, and 208 to 7460 mg/l respectively indicating a reduction in the palatability of groundwater below the waste dumpsites due to the presence of large amount of anions and cations. The analysis has so far indicated that the conce...
Arid Zone Journal of Engineering, Technology and Environment, 2018
Inadequate and improper supply and control of air are major causes of failures in gasifiers. La... more Inadequate and improper supply and control of air are major causes of failures in gasifiers. Lack of adequate number of blowers as well as tge use of unsuitable type of blower also lead to the total collapse of the gasification process.This research presents the design of a blower for use in the operation of a batch type downdraft gasifier, using analytical and numerical methods from the literature. The basic air requirements for gasification were considered as input parameters in order to determine the impeller design parameters. They included the geometrical parameters such as the tip diameter, hub diameter and tip width; operating conditions such as the inlet total pressure, inlet total temperature and fluid density; and performance characteristics such as mass flow parameter, pressure ratio and specific speed. The blower’s physical characteristics , geometric parameters and performance parameters were found and calculated to be I²1, I²2,U1, Vr2, as 42o , 90o, 17.52 m/s, 2...
Solar chimney power plant (SCPP) is a renewable energy facility that converts the potential energ... more Solar chimney power plant (SCPP) is a renewable energy facility that converts the potential energy in the Sun into kinetic energy and subsequently into electrical energy. The problem of global warming and electricity generation/distribution in Nigeria cannot be over emphasized; however with the vast land in the semi arid region and the potentials of the above technology, high prospects exist for solar chimney as it is a decentralized form of power generation. The aim of this paper was to theoretically evaluate the performance of the solar chimney power plant in semi-arid region of Nigeria, and estimate the amount of electrical energy that can possibly be generated. A mathematical model was used to estimate the amount of power generated, and determine the relationship between various meteorological and physical factors to the power produced. A solar chimney power plant with collector diameter of 700 m and chimney height of 700 m can produce up to 3000 MW of electricity.
The paper presents some basics and the steps required when the design of an incinerator for heat ... more The paper presents some basics and the steps required when the design of an incinerator for heat recovery or waste treatment is being thought of. It is mostly important for designers in developing countries and students where the advanced design tools and computer modelling are not easily accessible. Waste management has become a major concern world‐wide and amidst various waste treatment methods like recycling, composting; incineration is the method that treats the non-reusable and non-organic portion of wastes. Incineration is a complex process due to the heterogonous nature of wastes. Incinerators cannot be designed properly without the knowledge of the combustion science involved and the characteristics of the wastes. Aspects of prime importance in design to be considered are: the incineration mechanisms and their selection, the grate firing systems, furnace geometries, secondary air injection, the 3Ts, the heating value or calorific value of the waste, theoretical Air to Fuel r...
Biomass is a form of renewable and sustainable energy source with the highest potential to contri... more Biomass is a form of renewable and sustainable energy source with the highest potential to contribute to the energy needs of modern society for both the developed and developing countries. However, its usage in form of biofuels is still in the preliminary stage. There is a ...
This paper treats exergy analysis of rice husk at various loading rates of 1 kg, 1.5 kg and 2 kg ... more This paper treats exergy analysis of rice husk at various loading rates of 1 kg, 1.5 kg and 2 kg of feedstock, using a batch type, fixed-bed gasifier, equipped with a gas filtering system and between the operating temperatures of 690 K and 1100 K, operated for the whole year. Exergy analysis is a thermodynamic technique which uses conservation of mass and energy principles to design thermal systems with maximum efficiency and it is based on First and Second law of thermodynamics. Formulas from literature and previous researches as well as Microsoft Excel 2007 were used to make calculations and graphically interpret the results. The exergoeconomic analysis is based on location specific and national data collected from official sources. A MATLAB based hybrid model developed from a combination of other studies is used to generate the exergoeconomic analysis results. Methane was found with the highest total exergies where values of exergies were varying between 1110126 kJ and 1066279 kJ...
This study presents the design and testing of a waste-to-energy plant by incineration of small sc... more This study presents the design and testing of a waste-to-energy plant by incineration of small scale municipal solid waste to produce steam for electricity production. The average total waste generated within the study area was found to be 55,800kg/day, with an estimated calorific value of 13,958kJ/kg. The waste samples were collected, dried, shredded and weighed in order to reduce the moisture content to the acceptable minimum and decreases the surface area of the sample that will allow easier penetration of heat. The incinerator was designed using CATIA-5 software. The key performance indices of the developed plant are maximum furnace temperature, residence time, mass flow rate, steam pressures and amount of steam generated keeping the mass of waste constant per test but varying the air flow. The moving grate is inclined at an angle of 12° while the volume of the incineration combustion chamber was calculated to be 0.267m3. 150kg of small scale waste was fed into the combustion ch...
This paper treats the design of a small pedal operated briquette press to produce three (3) briqu... more This paper treats the design of a small pedal operated briquette press to produce three (3) briquettes of about 220mm length at a time using agricultural and wood wastes . The small light weight fuel briquette machine was successfully constructed using locally available materials and tested. The machine was able to produce 120 briquettes per hour and it will reduce the cutting down of trees for fuel-wood purposes, thereby preventing deforestation and erosion. Shrinkages were noticed and the final size of the briquette upon drying was observed to be 210 mm x 80 mm x 67 mm. The average true and apparent densities were also found to be 338.2 kg/m<sup>3</sup> and 263.04 kg/m<sup>3</sup> respectively. The effect of the binder content on the combustion potentials of the briquette needs to be investigated further. The product (briquette) obtained from the machine can be used as alternate to fuel-wood in domestic cooking and small-scale industries. The machine will a...
Biomass is a form of renewable and sustainable energy source with the highest potential to contri... more Biomass is a form of renewable and sustainable energy source with the highest potential to contribute to the energy needs of modern society for both the developed and developing countries. However, its usage in form of biofuels is still in the preliminary stage. There is a need to identify a suitable biofuel in terms of availability, which can provide high-energy output to supplement the rapidly depleting fossil fuels. Animal wastes are rich sources of energy and they are abundantly found in the semiarid regions. The energy from the waste material is extracted by anaerobic digestion of the organic matter by bacteria. This paper covers the design, cost analysis, construction and testing of a family size biogas plant for use under local conditions, and safety features for the prospect of large biogas production in semi arid regions. Plants were constructed and tests were conducted at the workshop of the University of Maiduguri in Nigeria; and the gas produced was found to be burning c...
Arid Zone Journal of Engineering, Technology and Environment, 2017
This paper presents a numerical simulation of air velocity and air temperature distribution in an... more This paper presents a numerical simulation of air velocity and air temperature distribution in an office room of Computer Engineering Department of University of Maiduguri which is naturally ventilated. The office room under investigation with the dimension 5 m × 5 m × 4 m has a door in the East direction, and two windows, one in the East direction and the other in the South direction. For cost effectiveness, numerical solutions of steady-state airflow and heat transfer were done using a complete two-dimensional model. The results showed that the windows and the door could not undertake indoor heat load that can make the occupants to be thermally comfortable. In activity area where people sit and stand, the air velocity is moderate, this is about 0.98 m/s on the average. In addition, the temperature in this area is relatively high of about 302 K (29 °C) on the average. Based on the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) standard for comfor...
ATBU Journal of Science, Technology and Education, 2016
Thermal comfort has a great influence on the productivity and satisfaction of indoor building occ... more Thermal comfort has a great influence on the productivity and satisfaction of indoor building occupants. The exposure to excessive heat or cold during work may cause discomfort and contributed to low productivity among workers. Maiduguri, Borno State is known with its hot and cold condition during summer and hammattan weather respectively. Unimaid Engineering workshop had exposed to excessive temperature during summer and excessive cold during hammattan while working. The study investigates the thermal comfort level experienced by students at Unimaid Engineering workshop during hammattan season. The study had been conducted at the machining section, the foundry unit, fabrication section and engine section. The environmental factors examined were the relative humidity (%), air temperature and air velocity of the workshop area. The environmental factors were measured using Luton apparatus, which is capable of measuring simultaneously those mentioned environmental factors. Then thermal...
ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ANGLAIS The paper focused on th... more ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ABSTRACT (ENGLISH/ ANGLAIS The paper focused on the mathematical modellin g and simulation of low calorific value municipal solid waste incineration in semiarid region. Municipal solid wastes were collected and analysed; from which wood samples were taken and incinerated using a prototype incinerator. A mathematical model, based on Fourier series (FS) and finite elements method (FEM) was developed, ran and validated using experimental and literature data. Critical minimum volume of 4.93 m 3 or about 6 % of the total volume of the incinerator would be needed at 20% moisture content refuse and a critical maximum volume of 51.10 m 3 or 69.21% of the total volume, would be needed at 50% moisture content. The ignition time and the time at which the combustion becomes self-sustaining are greatly influenced by the moisture content. Critical drying temperature was found to be 711.44 K. The grid size had little or no effect on the simulated resu...
Arid Zone Journal of Engineering, Technology and Environment, 2017
The study presents an application of the artificial neural network model using the back propagati... more The study presents an application of the artificial neural network model using the back propagation learning algorithm to predict the actual calorific value of the municipal solid waste in major cities of the northern part of Nigeria, with high population densities and intense industrial activities. These cities are: Kano, Damaturu, Dutse, Bauchi, Birnin Kebbi, Gusau, Maiduguri, Katsina and Sokoto. Experimental data of the energy content and the physical characterization of the municipal solid waste serve as the input parameter in nature of wood, grass, metal, plastic, food remnants, leaves, glass and paper. Comparative studies were made by using the developed model, the experimental results and a correlation which was earlier developed by the authors to predict the energy content. While predicting the actual calorific value, the maximum error was 0.94% for the artificial neural network model and 5.20% by the statistical correlation. The network with eight neurons and an R2 = 0.9688...
ENGLISH/ANGLAIS] Affiliations: 1 Department of Mechanical Engineering, University of Maiduguri, P... more ENGLISH/ANGLAIS] Affiliations: 1 Department of Mechanical Engineering, University of Maiduguri, PMB: 1069, Borno State, NIGERIA 2 National Agency for Science and Engineering Infrastructure (NASENI), Abuja, NIGERIA 3 Department of Mechanical Engineering, Ramat Polytechnic, PMB: 1070, Maiduguri; Borno State, NIGERIA Address for Correspondence/ Adresse pour la Correspondance: [email protected] Accepted/Accepté: September, 2012 Citation: Oumarou MB, Dauda M, Abdulrahim AT, Abubakar AB. Municipal Solid Waste Generation, Recovery and Recycling: a Case Study. World Journal of Engineering and Pure and Applied Science 2012;2(5):143-7. The paper presents a case study focused on waste generation, material recovery, and the recycling potential of municipal solid waste in Maiduguri, Nigeria. The municipal solid waste (MSW) generation was estimated using a fuzzy logic based mathematical model followed by a collection scenario thought of, adopted and tested within two planned residential areas; ...
In a hot climate like Maiduguri, one of the conventional approaches for providing comfortable env... more In a hot climate like Maiduguri, one of the conventional approaches for providing comfortable environment is the use of natural ventilation. In some cases, this strategy does provide the suitable thermal environment in a large space building such as the mosque. This study evaluated the thermal comfort of a naturally ventilated large space building, the university of Maiduguri central mosque in Maiduguri, Borno state during different times of daily prayers. The field study was conducted in 16th December 2015 (harmattan season) and April 2016 (hot season) during subuh, zuhr, Asri, Magrib and Ishai prayer times. During these days, the objective measurement using LUTRON ABH-4224 Cup Anemometer instrument and subjective assessment using questionnaire were accomplished. The objective parameters measured were air temperature, relative humidity and air velocity and the subjective responses concern the thermal condition of the respondents. Through linear regression analysis, Predictive Mean ...
R12 has been replaced with R134a due to its zero ozone depletion potential (ODP) in refrigeration... more R12 has been replaced with R134a due to its zero ozone depletion potential (ODP) in refrigeration system. The material compatibility and safety of R134a in refrigeration units as made it to be more attractive. However, R134a is to be phased out due to its high Global Warming Potential (GWP) and immiscible nature with conventional mineral oil. This paper presents the theoretical assessment of energy performance of a large capacity freezer using R134a and R430A as alternative refrigerant. In assessing the performance, three different condensing temperatures, that is, 40, 50 and 60oC and evaporator temperature between -30 and -18oC were chosen. The thermodynamic and thermophysical properties, namely, vapor pressure, latent heat, viscosity and density, using R134a and R430A refrigerants were compared. The performance parameters, such as coefficient of performance (COP), compressor power consumption (CPC) and Pressure ratio (Pr) were also compared. The results showed similarity in the va...
Arid Zone Journal of Engineering, Technology and Environment, 2015
This study investigates the performance of a micro Horizontal Axis Wind Turbine (HAWT) blade usin... more This study investigates the performance of a micro Horizontal Axis Wind Turbine (HAWT) blade using Computational Fluid Dynamics (CFD). The 1.5 m long micro HAWT blade was designed using the Blade Element Momentum Theory (BEM). Parameters such as the chord length lift force, drag force, tip speed ratio, solidity, coefficient of performance, angle of attack, wind relative angle, Reynolds number, efficiency, axial and induction factors were determined. Based on the design parameters the micro blade was created, meshed and boundary conditions identified in a 2D pre-processor Gambit interface. The meshed blade was exported to Fluent where it was processed and analyzed based on the identified boundary condition. The blade was simulated based on Maiduguri environment which has a recorded average wind speed of 3.89 m/s and the result showed that the maximum extractable power was 142.66 watts at a wind relative velocity of 4.8m/s when the blade was at 8o angle of attack and 3 x 106 Reynolds ...
The paper treats the design of a municipal solid waste incinerator suited to the semiarid regions... more The paper treats the design of a municipal solid waste incinerator suited to the semiarid regions with northern Nigeria and Niger Republic in West Africa as the study area. Proximate and ultimate analyses results from the solid waste were used as basis for calculations, using standard formulas and correlations. The calorific value of the solid waste samples in the study area is not high enough to sustain an incineration process and it ranges from 5.024 MJ/kg to 5.867 MJ/kg. For these types of low calorific value fuels, the parallel flow concept was found to be the appropriate type of incinerator. The solid waste to be fed in the incinerator needs to be mixed with 50% of supplementary fuel in the form of readily available bagasse to make it up to the required lower calorific value. Major characteristics of the designed municipal solid waste incinerator were: total volume of incinerator chamber: 82.5 m 3 , length of the incinerator bed: 11m; width of the incinerator bed: 3m and height...
Arid Zone Journal of Engineering, Technology and Environment, 2017
This study characterized and analysed the constituents of the leachates from four uncontrolled an... more This study characterized and analysed the constituents of the leachates from four uncontrolled and unlined waste dumpsites in Maiduguri, North eastern Nigeria. The leachate samples were carefully collected from waste dumpsites without any conventional collection equipment and transferred to the laboratory for analysis. The ionic concentration, pH, electrical conductivity (EC), and total dissolved solids (TDS) were determined using a conductivity meter, potassium and sodium by photometer; chlorine and calcium by titration method, BOD was computed from dissolved oxygen as determined by Winkler’s method and the UNICAM 969 Atomic Absorption Spectrophotometer was used to measure the cation and anion concentrations. The pH and TDS values ranged between 8.19 to 11.32, and 208 to 7460 mg/l respectively indicating a reduction in the palatability of groundwater below the waste dumpsites due to the presence of large amount of anions and cations. The analysis has so far indicated that the conce...
Arid Zone Journal of Engineering, Technology and Environment, 2018
Inadequate and improper supply and control of air are major causes of failures in gasifiers. La... more Inadequate and improper supply and control of air are major causes of failures in gasifiers. Lack of adequate number of blowers as well as tge use of unsuitable type of blower also lead to the total collapse of the gasification process.This research presents the design of a blower for use in the operation of a batch type downdraft gasifier, using analytical and numerical methods from the literature. The basic air requirements for gasification were considered as input parameters in order to determine the impeller design parameters. They included the geometrical parameters such as the tip diameter, hub diameter and tip width; operating conditions such as the inlet total pressure, inlet total temperature and fluid density; and performance characteristics such as mass flow parameter, pressure ratio and specific speed. The blower’s physical characteristics , geometric parameters and performance parameters were found and calculated to be I²1, I²2,U1, Vr2, as 42o , 90o, 17.52 m/s, 2...
Solar chimney power plant (SCPP) is a renewable energy facility that converts the potential energ... more Solar chimney power plant (SCPP) is a renewable energy facility that converts the potential energy in the Sun into kinetic energy and subsequently into electrical energy. The problem of global warming and electricity generation/distribution in Nigeria cannot be over emphasized; however with the vast land in the semi arid region and the potentials of the above technology, high prospects exist for solar chimney as it is a decentralized form of power generation. The aim of this paper was to theoretically evaluate the performance of the solar chimney power plant in semi-arid region of Nigeria, and estimate the amount of electrical energy that can possibly be generated. A mathematical model was used to estimate the amount of power generated, and determine the relationship between various meteorological and physical factors to the power produced. A solar chimney power plant with collector diameter of 700 m and chimney height of 700 m can produce up to 3000 MW of electricity.
The paper presents some basics and the steps required when the design of an incinerator for heat ... more The paper presents some basics and the steps required when the design of an incinerator for heat recovery or waste treatment is being thought of. It is mostly important for designers in developing countries and students where the advanced design tools and computer modelling are not easily accessible. Waste management has become a major concern world‐wide and amidst various waste treatment methods like recycling, composting; incineration is the method that treats the non-reusable and non-organic portion of wastes. Incineration is a complex process due to the heterogonous nature of wastes. Incinerators cannot be designed properly without the knowledge of the combustion science involved and the characteristics of the wastes. Aspects of prime importance in design to be considered are: the incineration mechanisms and their selection, the grate firing systems, furnace geometries, secondary air injection, the 3Ts, the heating value or calorific value of the waste, theoretical Air to Fuel r...
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Papers by M. Ben Oumarou