Life cycle assessment (LCA) is an extremely useful tool to assess the environmental impacts of a solar photovoltaic system throughout its entire life. This tool can help in making sustainable decisions. A solar PV system does not have any operational emissions as it is free from fossil fuel use during its operation. However, considerable amount of energy is used to manufacture and transport the components (e.g. PV panels, batteries, charge regulator, inverter, supporting structure, etc.) of the PV system. This study aims to perform a comprehensive and independent life cycle assessment of a 3.6 kWp solar photovoltaic system in Bangladesh. The primary energy consumption, resulting greenhouse gas (GHG) emissions (CH4, N2O, and CO2), and energy payback time (EPBT) were evaluated over the entire life cycle of the photovoltaic system. The batteries and the PV modules are the most GHG intensive components of the system. About 31.90% of the total energy is consumed to manufacture the poly-crystalline PV modules. The total life cycle energy use and resulting GHG emissions were found to be 76.27 MWhth and 0.17 kg-CO2eq/kWh, respectively. This study suggests that 5.34 years will be required to generate the equivalent amount of energy which is consumed over the entire life of the PV system considered. A sensitivity analysis was also carried out to see the impact of various input parameters on the life cycle result. The other popular electricity generation systems such as gas generator, diesel generator, wind, and Bangladeshi grid were compared with the PV system. The result shows that electricity generation by solar PV system is much more environmentally friendly than the fossil fuel-based electricity generation. ©2019. CBIORE-IJRED. All rights reserved

A 2-dimensional computational analysis is carried out for a time dependent double diffusive mixed convection flow using non-Newtonian nanofluid. A square-shaped cavity with a corrugated bottom wall is taken with higher temperature and concentration on the top wall. The physical model under consideration is represented by a set of governing equations and solved using the Galerkin weighted residual method based on Finite Element Analysis. Solutions are done for 4 controlling parameters such as Richardson number (Ri = 0.1 - 15), Lewis number (Le = 0.5 - 3), and thermophoresis parameter (Nt = 0.2 - 0.9), and Brownian motion parameter (Nb = 0.2 - 1.0) at different values of τ. For the aforementioned parameters, heat and mass transfer rates, temperature distributions, velocity distributions, and mass distributions in terms of isotherm, streamlines, and iso-concentration are graphically presented. It has been observed that for higher values of Ri, both Nuav and Shav increased while Le decreased for higher values of Nt at any fixed time. It is worth noting that the considered parameter exhibits consistent behavior after a while. HIGHLIGHTS The numerical analysis of non-Newtonian nanofluid with a corrugated bottom wall and a sliding upward wall is performed using Buongiorno's mathematical model The effect of the Richardson number, Lewis number, Brownian motion, and thermophoresis parameters on different dimensionless time periods is addressed The heat and mass transfer rate is increased as the Richardson number, Lewis number, Brownian motion, and thermophoresis parameters increase in value GRAPHICAL ABSTRACT

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