Journal of Energy Research and Reviews

Poly(3-hexylthiophene-2,5-diyl) with the acronym P3HT and its derivatives are p-type conjugated semiconductor polymers that have been proved to be good organic semiconductors. They have several applications in many areas, such as photovoltaic systems, organic light-emitting diodes, and so on. The instability of organic molecules under ambient conditions is one factor deterring the commercialization of such organic semiconductor devices. Here we present a theoretical study using density functional theory (DFT) approach with Gaussian 09 and GaussView 5.0, to investigate the effects of halogens (Bromine, Chlorine, Fluorine and Iodine) on the electronic and nonlinear optical properties of poly(3-hexylthiophene-2,5-diyl) (P3HT). This is to enable us to address the issue of instability in the molecule. The bond lengths and bond angles of the mono-halogenated molecules were found to be less than that of the isolated Poly(3-hexylthiophene-2,5-diyl). Iodine doped P3HT was found to be the most stable amongst the studied molecule for having the least bond angles and bond lengths. The calculated band gap for iodine doped P3HT and fluorine doped P3HT were observed to have the lowest energy gap of 3.519 eV and 3.545 eV respectively thus proving that iodine doped P3H is the most stable and this makes it more suitable for photovoltaic applications. The molecule with the highest value of chemical hardness was obtained to be the isolated P3HT with a chemical hardness of 1.937eV. This is followed by bromine doped P3HT, chlorine doped P3HT, fluorine doped P3HT and iodine doped P3HT with values as 1.925 eV, 1.813 eV, 1.773 eV, and 1.7595 eV respectively. All the substituted molecules results were found to be more reactive than their isolated form for having lower values of chemical hardness. The results for the nonlinear optical (NLO) properties show that the  first-order hyper-polarizability of chlorine doped P3HT and iodine doped P3HT as  and   respectively were found to be about eight times more than that of the urea value (0.3728 x10^-30 esu), which is commonly used for the comparison of NLO properties with other materials. This makes them very good NLO materials. The open circuit voltage   was also calculated. The highest values of the calculated open circuit voltage  were found to be    (PCBM C₆₀) in chloroP3HT and 1.3134 eV (PCBM C₆₀) in flouroP3HT. The results of the IR frequency show that the doped molecules are more stable than the isolated molecule. Zero-point vibrational energy (ZPVE), total entropy (S) and molar heat capacity (Cv) were also calculated and presented. We also observe that the entropy and heat capacity of the doped materials are higher than those of the original molecule, which confirms that the charge dynamics of the doped molecules are higher than those of the original molecule at the same temperature. This result further demonstrates that these doped materials have a high chemical reactivity and a high thermal resistivity, hence their application in the fields of organic electronics. By and large the overall results confirm that there is a good electron transfer within the doped molecules which makes them have potential applications in photovoltaic devices.

A theoretical study of radiation heat transfer with reference to an optically thick fluid past an oscillating vertical flat plate with variable temperature in the presence of convection and radiation has been presented.  The fluid is considered to be a gray, absorbing-emitting radiation but non- scattering medium. The Rosseland flux approximation plays an important role in determining the effect of radiation heat transfer contribution. This problem is an improvement of Stoke’s first and second problem to justify the physical signifance on this problem. This problem is solved by employing Laplace transfrom method. Numerical results of velocity and temperature distributions are depicted graphically. Also, numerical results of frictional shearing stress and critical Grashof number are presented in tables.

This paper designed a stand-alone photovoltaic energy system for small-scale business outlets in rural areas, using Arogbo Community in Ese-Odo Local Government Area of Ondo State, Nigeria as a case study. Structured questionnaires were administered to 150 business outlets for energy audit. Total energy estimate and consumption for 8 hours daily operation were estimated from obtained information. Total energy demand of the outlets based on their appliances used per day with power factor of 0.8 and 15% tolerance for a maximum load of 355.228 kW was 1,894.844 kWh. The specific energy required for a typical outlet (Barbing Salon, Computer Centre and Hairdressing Shop) were (0.938, 9.04 and 10.87) kWh, and their photovoltaic equivalence were estimated as (1.266, 12.211 and 14.67) kWh respectively. The solar components for the outlets were estimated as (0.317, 3.053 and 3.66) kW solar modules on installation areas of (3, 28.4 and 34) m². Inverter ratings of (0.22, 4 and 6) kVA were selected for the respective outlets.  (1, 4, and 4) numbers of 12 V deep cycle batteries of (100, 150 and 150) AH were selected. Electricity generator capacities selected were (1, 4 and 6) kVA respectively.

With a growing global population and the constant striving for prosperity, comes a growing demand for energy. Biogas and its upgrading to biomethane are prosperous and sustainable energy sources that even allow the use of the natural gas infrastructure. Biogas production using different bacterial cultures for wastewater treatment can be decentralized and without high costs. This aim of this research is focused on the co-digestion of wastewater biosolids and bacteria from a commercial activated sludge reactor, and customary bacteria used for the treatment of septic systems sludge. The research was performed with a designed laboratory anaerobic fermentation system at 35-40°C (95-104°F).

The biomass-gas turnover rate is on average 170 l/kg for activated sludge reactor bacteria and 100 l/kg septic system bio bacteria.

The application of wastewater treatment bacteria as basis for anaerobic fermentation can be considered beneficial for biogas production within wastewater treatment plants.

Irrigation is an important area of Bangladesh where most cases it depends on fossil fuels, either diesel-powered irrigation systems or grid electricity-operated irrigation systems. Solar irrigation is an alternative way to promote clean energy in the irrigation sector which is in line to achieve the Sustainable Development Goals (SDG). A business model is essential for the promotion of Solar Irrigation Pumps (SIP), where alternative use of water and electricity after irrigation may play a vital role to make the business viable of solar irrigation pumps. Grid integration of SIP is one of the alternative uses where the techno-economic viability of SIP grid integration is an important issue to make acceptable to the solar irrigation operators. The government of Bangladesh published a dedicated grid integration guideline for SIP. Interested solar irrigation pump operators can take this facility by adding grid integration-related connections and additional equipment to their projects to supply surplus electricity into the distribution grid after irrigation uses. This paper analyzes the grid integration-related integration costing and surplus electricity pricing to understand the techno-economic viability of grid integration of solar irrigation pumps. According to the analysis result, higher-capacity solar irrigation pumps are financially viable for grid integration up to a certain distance. Also, this study gives a financial viability analysis of the combined grid integration of multiple SIPs.

The success of the SDGs has been a major challenge for governments around the world in recent years. This research focuses specifically on progress toward SDG 7, which aims to ensure that everyone has access to affordable and clean energy. The primary goal of this paper was to assess progress toward SDG 7 objectives in India and Indian states and UTs. Using SDG Index reports for 2018, 2019 and 2020, we assess the progress made in terms of SDG 7. The findings revealed that for SDG 7, the SDG Index Score ranges between 50 and 100 for States and 71 to 100 for UTs. There are fifteen states and five UTs in the class of Achievers (with an Index score of 100) and twelve states and three UTs in the class of Front Runners (with an Index score ranges between 65 and 99). The paper raises various policy issues, including drafting of regulations that benefit the poor and marginalized sections of the society, as well as states and areas that lack access. The importance of formal education, especially for rural women, cannot be overstated, which impacts their decisions about the type of fuel used for cooking. Through strong collaboration between non-state organizations and the government in rural communities within the country, the SDG 7 goals can be achieved through effective planning and delivery of reforms, thereby reducing the harmful effects of the lack of access to clean and affordable energy. It will be crucial in the long run for effective participation of local institutions (PRIs) to carry out reforms in the energy sectors to have adequate budgetary allocations for providing access to affordable energy services.

The continuous use of non-renewable energy sources has caused a lot of harm to the earth’s atmosphere and humans. The need to increase the share of renewable energy in global energy usage has been strongly advocated internationally. In this work, wind energy was presented as a viable renewable energy option. Renewable energy with emphasis on wind energy, wind turbines and its types, the need for it to replace other injurious energy sources and the associated challenges hampering its deployment is a contribution toward the UN advocacy. The potential of wind energy and their technologies in terms of the turbine types: Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines (VAWT) including their mix were reviewed. Looking at the pros and cons of both the HAWT and the VAWT, and those of Savonius and Darrieus, it is imperative to strike a balance using their combinations. Such a hybrid offers the benefit of harnessing the gains on either side of the divide.  This is the reason attention is being devoted to research and development on combined VAWT in order to optimize the low starting torque of a Savonius with the high-performance coefficient of the Darrieus as the efficiency of VAWT increases when combined together with diverse modifications.  With the volume of on-going research targeted at the implementation challenges and various design considerations and practices to solve the problems, it is certain that these impediments will be tackled technologically and policy wise and society will be on its way to better utilization of enormous wind energy resources via interception using wind turbines. The technical challenges on the pathway towards the smooth implementation of wind energy technologies were identified to include output fluctuations and intermittencies; and to which solutions were proffered to include the need for a technology to always align and realign the blade position in a way as to maximally interact with the current prevailing wind direction and another to reinforce the rotors rotational speed with an appropriate speed required to meet up the rated output. It was recommended that attention be devoted to research and development on the combined vertical axis wind turbine (VAWT) in order to optimize the high starting torque of the Savonius turbine with the high-performance coefficient of the Darrieus turbine.

Aims: This work aims to design a single-phase transformer for analyzing its performance based on some requirements.

Study Design:  At first, requirements are set, then the design was completed using AutoCAD, after that the designed machine was simulated in MATLAB Simulink, manufactured in real-time in the laboratory, tested experimentally, and then the equivalent circuit parameters were computed from the experimental data.

Place and Duration of Study: The design, manufacturing, simulation, and performance testing were conducted in the electrical machine 1 laboratory of American International University-Bangladesh (AIUB). It took around four months to complete the whole task.

Methodology: This work is a bit expensive and complicated process for students without any funds. So, a group was formed with eight students. The tasks were to design, simulate, implement, and test a single-phase transformer that would step down 220 V (ac) to 110 V (ac) having a 440 VA capacity, and core loss should not exceed 5 W.

Results: MATLAB Simulink was used to simulate the designed transformer to get the primary and secondary winding voltage and current wave shapes that were confirmed by the experimental results. Open and short circuit tests indicate that loss is only between 5 W and 8 W respectively. The total design cost is only BDTK1, 270.

Conclusion: The results satisfied the design and performance parameter requirements and the designed transformer worked very well. The design cost was also kept minimum.