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Numerical Simulation and Performance Assessment of a Nanoparticle Enhanced Vapour Compression Refrigeration System

Journal of Power and Energy Engineering 2021年第11期9卷 33-49页

作者： moradeyo k. odunfa Oluwaseyi D. Oseni Department of Mechanical Engineering University of Ibadan Ibadan Nigeria

Cooling in industrial production and refrigeration of perishable and non- perishable products is common practice throughout the world. Research studies have been conducted both experimentally and numerically to simulate Vapor Compression Refrigeration System (VCRS) and its performance respectively, however, experimental procedure often seems to be expensive and time-consuming to carry out due to the function of many variables. This study was therefore designed to numerically simulate the performance assessment of a nanoparticle enhanced VCRS. A numerical model of a vapor compression refrigeration system was developed using standard refrigeration equations on each of the major components of the refrigeration system such as compressor, evaporator, condenser and expansion valve. The model was then simulated on a MATLAB platform with a CoolProp installed packages via Python under two different simulation cases. In the first case, the mass fractions were varied for CuO, TiO2 and Al2O3 nanoparticles while their densities remained constant and a reversed condition was investigated for the second case. The results showed that both the refrigerating effect and the Coefficient Of Performance (COP) of the system increase as both the mass fraction and density of all the nanoparticles increases. It also shows that the compressor work.decreases as both the mass fraction and density of all the nanoparticles were increased. On comparing the computational and numerical analysis results, the study established no significant difference in terms of COP and the use of nanoparticles were found to have improved the COP of the system.

关键词： CoolProp Coefficient of Performance Vapour Compression Refrigera-tion Mass Fraction

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Development of a Small Hydropower Plant: Case of Ik.re Gorge Dam, Oyo State, Nigeria

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Journal of Power and Energy Engineering 2019年第3期7卷 31-45页

作者： moradeyo k. odunfa Timiepiri C. Saudu Temitayo E. Oladimeji Mechanical Engineering Department University of Ibadan Ibadan Nigeria Chemical Engineering Department Covenant University Ota Nigeria

Energy crisis and environmental safety has become a thing of global concern, Nigeria inclusive. This is due to the increasing energy prices and environmental impact. Energy generated from the non-renewable energy sources has been link.d up with this energy crisis and non-friendly environment. Research is therefore been geared towards harnessing renewable energy resources as alternative sources of energy generation. Renewable energy sources such as hydropower, wind, geothermal and solar just to mention a few are environmentally friendly. This study therefore aims at exploring renewable energy sources and thus designing a small hydropower plant using Ik.re gorge Dam as case study. A survey was conducted through personal interview and probing of previous records of the site. Basic parameters such as flow rate of 31.8 m3/s and a head of 30 m were obtained. These parameters were used together with the standard equations for the design of the small hydropower plant. Costing analysis of the plant was carried out in other to estimate the cost of the plant. The comparative analysis of the renewable and non-renewable energy sources was also carried out. The theoretical power obtained for small hydropower project is 9.36 MW. The initial cost of the project is estimated at N63,343,970 with an estimated annual maintenance cost of N500,000. The annual energy output is 3.6 × 107 k.h and the project has estimated annual revenue of N579,960,000. When compared with other renewable energy sources, the cost of small hydropower plant is low and when compared with dwindling oil prices and environmental effects of non-renewable energy sources, small hydropower stands second to none. The study established that Ik.re gorge Dam is a feasible site for a small hydropower plant and a small hydropower plant has also been designed;hence small hydropower plant is therefore recommended.

关键词： Renewable Energy Non-Renewable Energy Environmental Safety Ik.re Gorge

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Magnetic Field Enhancement in Ammonia-Water Absorption Refrigeration Systems

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Energy and Power Engineering 2014年第4期6卷 54-68页

作者： moradeyo k. odunfa Richard O. Fagbenle Olanrewaju M. Oyewola Olayink. S. Ohunak.n Mechanical Engineering Department Covenant University Ota Nigeria Mechanical Engineering Department Obafemi Awolowo University Ile-Ife Nigeria Mechanical Engineering Department University of Ibadan Ibadan Nigeria

Absorption enhancement has been considered as an effective way of improving coefficient of performance (COP) of refrigeration systems and magnetic enhancement is one of these methods. A model of magnetic field enhancement in ammonia-water absorption systems is presented in this paper. A numerical model using finite difference scheme was developed based on the conservation equations and mass transport relationship. Macroscopic magnetic field force was introduced in the momentum equation. The model was validated using data obtained from the literature. Changes in the physical properties of ammonia solution while absorbing both in the direction of falling film and across its thick.ess were investigated. The magnetic field was found to have some positive effect on the ammonia-water falling film absorption. The results indicate that absorption performance enhancement increased with magnetic intensity. The COP of simple ammonia solution absorption refrigeration system increased by 1.9% and 3.6% for magnetic induction of 1.4 and 3.0 Tesla respectively.

关键词： Ammonia-Water Absorption Refrigeration Magnetic Field Force Ammonia Solution Concentration Coefficient of Performance Finite Difference Scheme Numerical Solution

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Energy and Cost Analysis of Cement Production Using the Wet and Dry Processes in Nigeria

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Energy and Power Engineering 2013年第9期5卷 537-550页

作者： Olayink. S. Ohunak.n Oluwafemi R. Leramo Olatunde A. Abidak.n moradeyo k. odunfa Oluwafemi B. Bafuwa Mechanical Engineering Department Covenant University Ota Nigeria Mechanical Engineering Department Covenant University Ota Nigeria.

The study evaluates the energy consumption of both wet and dry processes cement manufacturing plant in Nigeria. Enrgy consumption data collected for the period 2003 to 2011 were used to estimate the energy consumption of the crushing, milling, agitation, burning, grinding and bagging operations. The total energy evaluation was based on the three primary energy sources which include electrical, combustion and human. The total estimated energy intensities were 6545 MJ/ton and 4197 MJ/ton for wet and dry processes respectively. The percentage consumption of energy in each operation is 93.68 and 90.34% (burning), 2.11 and 4.33% (milling), 0.43 and 0.67% (crushing), 1.39 and 0% (agitation), 2.12 and 3.90% (grinding), and 0.27 and 0.75% (bagging) of the total energy inputs for the wet and dry processes respectively. Furthermore, the average total energy cost of production showed that wet process is approximately 40% more cost intensive in cement production than the dry process while at the same time it is cost effective to run production on energy through gas powered plant than the national grid.

关键词： Wet Process Dry Process Cement Crushing Milling Nigeria

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Building Energy Efficiency in Nigeria Major Climatic Zones

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Journal of Building Construction and Planning Research 2018年第4期6卷 251-266页

作者： k. M. odunfa C. J. Nnak.e V. O. odunfa Mechanical Engineering Department University of Ibadan Ibadan Nigeria Estate Management Department The Polytechnic Ibadan Ibadan Nigeria

Energy consumption in both residential and public buildings has been established globally as been significantly high. The need to incorporate energy efficiency in building therefore becomes imperative in order to minimize the consumption level. This work.therefore examines the effect of building orientation coupled with different building material composition on energy efficiency in building within major Nigeria climatic zones. The methodology adopted in this study entails carrying out a load survey and thereby calculating the cooling load required to condition the building space in two selected different orientations within the major Nigerian climatic zones. The standard cooling load equations were utilized in the evaluation of the various cooling loads. The selected locations considered within major Nigerian climatic zones are Ibadan in the South West, Jos in the middle belt and Maiduguri in the North East. The cooling load results obtained for the two different orientations are as follows;151.45 k. and 163.17 k. for Ibadan, Maiduguri: 164 k. and 175.78 k., and 131.77 k., 143.4 k. for Jos. The first orientation being North/South longitudinal placement of the building while the second orientation is East/West longitudinal placement respectively. The study established that the second orientation generated more cooling load. It is therefore concluded that the first orientation which is the North/South longitudinal placement of the building is best recommended. It also established the dependence of cooling load on the climatic condition of the building’s location. Both building material compositions coupled with its orientation and climatic condition therefore play major significant role on the energy consumption in a building space.

关键词： Orientation Cooling Load Thermal Storage Material Composition Load Survey

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Visual Interactive Computer Pack.ge for Air Conditioning System Design: Case of the International Conference Centre, University of Ibadan, Nigeria

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Journal of Building Construction and Planning Research 2018年第4期6卷 317-330页

作者： k. M. odunfa T. O. Arowona V. O. odunfa Mechanical Engineering Department University of Ibadan Ibadan Nigeria Estate Management Department The Polytechnic Ibadan Ibadan Nigeria

Air conditioning design has become an interesting aspect of human life with the aim of seek.ng environmental comfort for indoor spaces. Analytical work.involves in the design of air-conditioning system is often time consuming and laborious. This work.therefore aims at developing a visual interactive computer pack.ge for the design of air conditioning system using the international conference centre, University of Ibadan, Nigeria as a case study. Procedures for calculating heat gain through various building components were discussed in detail. Cooling load analysis was carried out using standard cooling load equations obtained from the American Society of Heating, Refrigeration and Air conditioning Engineers (ASHRAE) handbook. A computer program was developed using java programming language to compute the total cooling load in the building. The result from the computer program was obtained within a very short period of time when compared with that of the manual one. The cooling load of the building obtained was 3,194,414 btu/hr;a visual interactive computer pack.ge for the design of air conditioning system has been developed and tested positively;hence can be used to design air conditioning system for any building.

关键词： Environmental Comfort Programming Language Air Conditioning Design

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Energy Efficiency in Building: Case of Buildings at the University of Ibadan, Nigeria

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Journal of Building Construction and Planning Research 2015年第1期3卷 18-26页

作者： k. M. odunfa T. O. Ojo V. O. odunfa O. S. Ohunak.n Department of Mechanical Engineering University of Ibadan Ibadan Nigeria Department of Estate Management The Polytechnic Ibadan Ibadan Nigeria Department of Mechanical Engineering Covenant University Ota Nigeria

Nigeria today faces serious challenge in providing adequate energy to meet the needs of her citizenry. Efforts are currently geared towards generation of more energy to ease the problem. While these efforts are commendable, it is equally desirable to explore ways to minimize consumption of generated energy. The objective of this work.is to investigate the effect of building orientation on energy demand in buildings. This paper considered the use of standard design considerations, fundamental cooling load equations and the guidelines stipulated by the American Society of Heating, Cooling and Air conditioning Engineers (ASHRAE). The study tak.s the designs of three buildings within the University of Ibadan, Nigeria into consideration with the view to harness the energy saving potentials through building orientation and selection of efficient cooling equipment. The results obtained were 155.34, 224.75, 86.35 k. and 163.60, 232.04 and 90.64 k. for the three lecture envelopes including the Faculty of Science, CBN and the Department of Chemistry lecture theatres using the North-South and East-West building orientations respectively. Increase in energy demand of 7.96, 7.29 and 4.29 k. was thus obtained with the East-West building orientation over North-South. Energy efficiency is thus guaranteed with North-South building orientation.

关键词： Energy Efficiency Orientation Cooling Load Heating Ventilation and Air-Conditioning

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