Energy
S. A. Gandjalikhan Nassab
Abstract
This paper deals with the development of compound parabolic collectors (CPCs), utilizing a partial glass sheet adjacent to the absorber plate for the purpose of performance improvement. The collector under study has a parabolic shape, whose cavity is filled with air and the turbulent natural convection ...
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This paper deals with the development of compound parabolic collectors (CPCs), utilizing a partial glass sheet adjacent to the absorber plate for the purpose of performance improvement. The collector under study has a parabolic shape, whose cavity is filled with air and the turbulent natural convection takes place because of the air density gradient. The main goal is the reduction of heat losses by keeping away the high-temperature region near to the absorber from the main recirculaetd convection airflow by installation of a separating glass sheet. The conservations of mass, momentum and energy as the set of governing equations for the steady and turbulent free convection airflow in the CPC’s cavity and the Laplace equation for computation of temperature distributions in solid parts including the glass cover, absorber plate, and glass sheet were numerically solved by the finite element method. The COMSOL Multiphysics software was used for the present simulation. For the computation of turbulent stress and heat flux, the κ-ε turbulence model was employed. An attempt was made to investigate the installation of a fully transparent glass sheet near the absorber plate on the thermal behavior of the studied CPC. It is expected that this factor leads to lowering the heat losses from boundary surfaces, especially from the glass cover. Numerical findings showed about a 24% increase in the efficiency of studied test cases because of the installed glass sheet. Comparison between the theoretical findings with experiment shows good consistency.
E. O. Ajala; F. Aberuagba; M. A. Ajala; A. M. Ayanshola; T. D. Akpenpuun
Abstract
Shea biodiesel (SBD) was produced and blended with diesel at various proportions to produce 100B (SBD), 75B, 50B, 25B, and D (diesel) as fuel types. The SBD and other fuel types were characterised by ASTM standard methods for its physicochemical properties. The fuel types were used in a compression ignition ...
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Shea biodiesel (SBD) was produced and blended with diesel at various proportions to produce 100B (SBD), 75B, 50B, 25B, and D (diesel) as fuel types. The SBD and other fuel types were characterised by ASTM standard methods for its physicochemical properties. The fuel types were used in a compression ignition engine (CIE) to test for its fuel consumption, (FC) specific fuel consumption (SFC), brake thermal efficiency (BTE), exhaust temperature (ET) and emission characteristics hydrocarbon (HC), carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxide (NOx) and sulphur dioxide (SO2). The physicochemical properties of SBD in terms of density, kinematic viscosity, flash point, cloud and pour points, and cetane number were 884.7 kg/m3, 5.69 mm2/s, 165 oC, 12 oC, 9 oC and 55, respectively; while those of diesel were 860.4 kg/m3, 2.6 mm2/s, 73 oC, 2.4 oC, -9 oC and 49, respectively. The results were within the range of the standard. The results obtained at 12 Nm torque for SFC, FC, BTE, and ET for SBD were 0.21 kg/kW.h, 0.71 kg/h, 12.69%, and 365 oC, respectively, while those of diesel were 0.31 kg/kW.h, 1.12 kg/h, 8.46%, and 330 oC, respectively. These results show that the SBD and diesel possessed similarity in terms of performance. The SBD is environmentally friendly compared to diesel. This study shows that the SBD possessed quality alternative replacement to diesel suitable for a CIE.
M. M. Mirzaei Darian; A. M. Ghorreshi; M. J. Hajatzadeh
Abstract
Solar energy is a feasible and efficient way to reduce environmental pollution which, in turn, can decrease the production of greenhouse gases. Iran with over 300 sunny days has a high potential for producing energy, including electricity through photovoltaic (PV) systems. Regarding this fact that Iran ...
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Solar energy is a feasible and efficient way to reduce environmental pollution which, in turn, can decrease the production of greenhouse gases. Iran with over 300 sunny days has a high potential for producing energy, including electricity through photovoltaic (PV) systems. Regarding this fact that Iran has the enormous resources of fossil fuels such as oil and gas, the government tends to expand its energy production by renewable systems, including photovoltaics. This paper is to evaluate the efficiency of photovoltaic system in one of the major provinces of Iran. In this study, a 4.8 kW photovoltaic power station in East Azerbaijan province was investigated. First, a simulation-analysis is carried out. Then the verification of the study is done using extracted experimental data. According to the results, the photovoltaic power plant generates 8334 kWh annually. Finally, the station is economically investigated. This economic analysis is carried out in accordance with the existing tariffs and policies in Iran.
Nano-Biotechnology
A. Kumar Singh; R. Patle; M. Das; R. Sanodiya; N. M. Stanley; P. Malkhani
Abstract
Applications of nano-scaled energetic materials in diesel and diesel-biodiesel blends as catalytic agents have emerged contemporarily in pace to develop an efficient and eco-friendly alternative fuel for compression ignition (CI) engines. Inclusion of nanoparticles as additives for CI engine fuels promises ...
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Applications of nano-scaled energetic materials in diesel and diesel-biodiesel blends as catalytic agents have emerged contemporarily in pace to develop an efficient and eco-friendly alternative fuel for compression ignition (CI) engines. Inclusion of nanoparticles as additives for CI engine fuels promises as overall improver of engine performance and emission characteristics. However, simultaneous control on engine performance parameters and emission characteristics is usually difficult. Dispersion of nano-additives improves combustion efficiency by altering specific fuel properties of diesel. Average particle size of 40-50 nm facilitate greater surface-to-volume ratio, hence ensure more complete combustion through further chain reactions during combustion. Nanoparticles as catalytic agents in diesel and its proportionate blends have recently emerged as game changer but their potential is in-fact not fully explored for market acceptability. The following are the major challenges that are to be considered in future researches: (a) There is a need of on-road testing in real ambient conditions, (b) Effects of exhaust emission fuelled with nanocatalysts on human breathing, (c) Overall effects on diesel engines of agricultural tractors and other heavy earth moving machines which are designed for high load factors, and (d) Effects of such modified fuels on driving habits of consumers.
