Biomass energy in Bangladesh: current status and prospects

Bangladesh has been experiencing several problems over the past few decades. These include over population, energy crisis and global warming, etc. Adequate amount of power generation in a sustainable way is an important issue for rapidly increasing population and economic development. Renewable energy can play an effective role to meet energy demand. Since it is an agrarian country, biomass is one of the potential renewable energy sources in Bangladesh. Agricultural crop residues, animal manure and municipal solid waste are the major sources of biomass energy in the country. This paper presents the scope, potential and technologies related to the use of biomass resources. The study also discusses the biomass projects undertaken by the government and non-government organizations, plans and strategies to promote biomass technologies in Bangladesh

A finite element analysis on combined convection and conduction in a channel with a thick walled cavity

Purpose: The purpose of this paper is to examine the effects of thick wall parameters of a cavity on combined convection in a channel. In other words, conjugate heat transfer is solved. Design/methodology/approach: Galerkin weighted residual finite element method is used to solve the governing equations of mixed convection. Findings: The streamlines, isotherms, local and average Nusselt numbers are obtained and presented for different parameters. It is found heat transfer is an increasing function of dimensionless thermal conductivity ratio. Originality/value: The literature does not have mixed convection and conjugate heat transfer problem in a channel with thick walled cavity

A new eight switch seven level boost active neutral point clamped (8S-7L-BaNPC) inverter

A new boost Active-Neutral-Clamped (ANPC) voltage boosting inverters are appealing for low dc-link voltage demand. Recent boost ANPC topology has demonstrated a 1.5 times voltage gain, but the number of switches has a higher number. This paper proposed an improved boost ANPC topology with 1.5 voltage gain using the least number of switches. Further, the number of conducting switches has been reduced remarkably which enhances the system efficiency. The seven-level (7L) output voltage levels are achieved using a floating capacitor with self-voltage balancing capability. The proposed topology has been analyzed and compared to the ANPC topologies proposed in recent years. For the validation of the theoretical aspect of the proposed topology, the experimental findings have been compiled in the paper.This work was supported by the Qatar University-Marubeni Concept to Prototype Development Research grant # [MCTP-CENG-2020-2] from the Qatar University and the publication charges is paid by the Qatar National Library, Doha, Qatar.Scopu

A Single DC Source Nine-Level Switched-Capacitor Boost Inverter Topology with Reduced Switch Count

This paper presents a new boost inverter topology with nine level output voltage waveform using a single dc source and two switched capacitors. The capacitor voltages are self-balancing and thus is devoid of any sensors and auxiliary circuitry. The output voltage is twice higher than the input voltage, which eliminates the need for an input dc boost converter especially when the inverter is powered from a renewable source. The merits of the proposed topology in terms of the number of devices and cost are highlighted by comparing the recent and conventional inverter topologies. In addition to this, the total voltage stress of the proposed topology is lower and have a maximum efficiency of 98.25%. The operation and dynamic performance of the proposed topology have been simulated using PLECS software and are validated using an experimental setup considering a different dynamic operation.This work was supported in part by the Scientific Research Deanship, Taif University, Saudi Arabia, under Grant 1-439 - 6072.Scopu

A review on palm oil biodiesel as a source of renewable fuel

The demand of increasing price in fossil fuel has prompted the global oil industry to look at the alternative sources of fuel from renewable energy source which is biodiesel. Biodiesel is considered as better option because of its environmental friendly characteristics while giving almost the same functional properties like fossil fuels. This paper will focus on the biodiesel produced in Malaysia. Palm oil is the main raw stock for biodiesel production in Malaysia as the country is one of the leading palm oil producers in the world. There are many advantages and disadvantages from the economical social and environmental aspects in the Malaysian biodiesel production in specific palm oil biodiesel. The aim of this paper is to analyze the past, current and future of palm oil biodiesel industry in Malaysia. This paper includes the technology aspect used in the palm oil biodiesel production and characteristics of pure palm oil biodiesel to meet the international market standard. Malaysia faces tough competition from other biodiesel producers like Indonesia and Brazil. The scope of this study covers the worldwide biodiesel development in brief in continuation with the challenges faced by Malaysia in becoming the top biodiesel exporter in the world with the advantages and disadvantage of using palm oil as the feedstock

Mathematical modelling and experimental validation of solar drying of mushrooms

This article presents two mathematical models for drying mushrooms considering the shrinkage effect. Both the models consider the physical changes of mushrooms during drying using the diffusion equation. A convective term is presented in the first model while, in the second model, the effective diffusion co-efficient is employed. Although the diffusion co-efficient is mainly dependent on the water content of the mushrooms, both models are suitable for analyzing the drying process. Moreover, in this study it has been demonstrated that both models are equivalent. The Genetic Algorithmic process was used to estimate the parameter values in different conditions. The information regarding the moisture content and the thickness evaluation taken from the models shows the best fit with the experimental data. The mathematical models developed to simulate the drying curve of mushroom have been evaluated and compared

Energy performance of an evacuated tube solar collector using single walled carbon nanotubes nanofluids

An experimental study was performed to determine the thermal efficiency of an Evacuated Tube Solar Collector (ETSC) using water based Single Walled Carbon Nanotubes (SWCNTs) nanofluids. Experiments were carried out using SWCNTs nanofluids having volume concentrations of 0.05, 0.1, and 0.2 vol.%. The performance of the collector was compared with SWCNTs nanofluid and water using the flow rates of 0.008, 0.017, and 0.025 kg/s. The experiments were undertaken according to ASHRAE standard 93-2003. The results show that, the collector efficiency improved with SWCNTs nanofluids compared to water as a working fluid. The maximum efficiency found to be 93.43% for 0.2 vol.% SWCNTs nanofluids at a mass flow rate of 0.025 kg/s. The collector efficiency shows greater enhancement with the increasing volume fractions of SWCNT nanoparticles and flow rate. In conclusions, results suggest that SWCNTs nanofluids can be used as the working fluids in an ETSC to absorb heat from solar radiation and to convert solar energy into thermal energy efficiently