• Energy Research
• IN close
• AU close
• BE close
• Energy Conversion and Management close

Microgrids are increasingly being used as a platform to integrate distributed generation such as renewable energy sources and (RESs) conventional sources in both grid-connected and isolated power systems. Due to the inherent intermittent nature of RESs, energy storage systems (ESSs) that can absorb fluctuations have become inevitable. Nevertheless, large capacities of ESSs increase the initial cost while small capacities lead to instabilities and increase in the cost of conventional fuels. Therefore, finding the optimal size of the ESS for a given application is essential for the reliable, efficient and economical operation of a microgrid. Once the battery size is decided, maintaining its energy at appropriate levels is essential to ensure stable and safe operation of the microgrid. This paper presents a novel expert fuzzy system - grey wolf optimization (FL-GWO) based intelligent meta-heuristic method for battery sizing and energy management. The proposed energy management operation is carried out by a Grey Wolf Optimiser (GWO) that is helped to set the membership functions and rules of the fuzzy logic expert system. The unit commitment (UC) issue, which is essential for the proper operation of the isolated microgrid, has been additionally considered in this paper. To verify the performance of the proposed method, results are compared with the rules-based method and traditional GWO algorithm. It has been proven from the results that the FL-GWO has a significant convergence property and capability to minimize the Levelized Cost Of Electricity (LCOE) by 14.13% and 24.15% compared with conventional GWO algorithm and rules-based method, respectively. The weather conditions for different climates is used to verify the performance of the intelligent energy management method under different operating scenarios. The results show that the intelligent online multi-objective energy management strategy is capable of managing a smooth power flow with the same optimal configuration in the isolated microgrid, minimising the fossil fuel utilisation and reducing the CO2 emission level.

Abstract Global hydropower growth continues to accelerate with 25% of total capacity installed in just the last 10 years. This accelerating expansion and the important storage facility hydropower means it is increasingly important to understand the reasons for operational failures. This is a challenge because the major reason for failures involves the complex interaction of hydraulic, mechanical and electric subsystems. Historically, reliability modelling has been split in two directions, focusing on different sub-systems, and has not yet been unified. Here these approaches are unified with a novel expression of unbalanced forces. This model with operational data are validated and the important modes of oscillation in the shaft are identified. Finally, the mechanism of the first-order oscillation mode exciting a second-order mode is presented. This integrated and accurate mathematical model is a major advance in the diagnosis and prediction of failures in hydropower operation.

Abstract Castor seed is an important oil seed crop of dryland agriculture. To estimate the energy needs of this crop, two experiments were conducted with three tillage treatments under two farming systems, namely bullock and tractor farming. Under all the selected tillage treatments both for tractor and bullock farming systems, it was found that threshing, harvesting, manual weeding and seed bed preparation were the energy intensive operations. No-tillage treatments was found not only the least energy consuming package of practices but also resulted i n a comparatively high output-input energy ratio despite higher weed intensity. Further, tractor cultivation consumed a higher amount of energy as compared to bullock cultivation but did not result in higher production. The farmer may, therefore, continue with bullock cultivation unless he were to cover larger areas which cannot be commanded by the bullock power resources available to him.

Abstract Biodiesel has gained the forefront of our focus on renewable transportation fuels. This article provides a comprehensive review on the sources used as feedstock and their classification based on generation or type (edible, non-edible, waste resources and animal fats) along with a variety of classical and modern oil extraction techniques. The technical aspects of the various biodiesel production methods currently implemented to the best of our knowledge are discussed here, which include in-situ biodiesel production, both catalysed (homogeneous and heterogeneous systems) and uncatalysed classical production approaches, with emphasis on how each of these approaches are affected by their reaction parameters. The review also highlights the observed drawbacks of each process with a view to assessing the implementation of supercritical and superheated technologies as an alternative, economically feasible advancement. Supercritical process (SCP) has shown great prospect in the obtainment of high quality biodiesel from a wide range of high to low grade feedstock with minimal impacts on the presence of water or FFAs (free fatty acids). From available literature it is shown that these do not affect the process significantly, and various other supercritical fluids such as methyl acetate, tert-butyl methyl ether (MTBE) and dimethyl carbonate can also be used to avoid glycerol formation. The process however, suffers from high initial implementation cost being the most prominent drawback, among others like thermal degradation of the fuel. Another promising technique, the superheated vapour technology (SHV) has emerged as an alternative, with limited literature proving the superiority of either of these processes to be inconclusive. In future works, researchers need to look into various aspects such as developing a spiral reactor for heat recovery, using software based optimization for eliminating redundant experiments analysing production cost for industrial scale-up and improving the fuel’s oxidative stability by adding antioxidants for convenient long-term storage and use.

Abstract In this study, parallel, bench-scale, mesophilic and thermophilic, dry, semi-continuous anaerobic digestion (DScAD) of Korea food waste (FW, containing 22% total solids (TS) and 20% volatile solids (VS)) was investigated thoroughly under varying operational conditions, including hydraulic retention times (HRTs) and organic loading rates (OLRs). The aim was to evaluate the start-up, stability, overall removal efficiency, and inhibitory effects of toxic compounds on process performance over a long-term operation lasting 100 days. The results from both digesters indicate that the simultaneous reduction of VS and the production of gas improved as the HRT decreased or the OLR increased. The highest average rates of VS reduction (79.67%) and biogas production (162.14 m 3 biogas/ton of FW, 61.89% CH 4 ), at an OLR of 8.62 ± 0.34 kg VS/m 3 day (25 days of HRT), were achieved under thermophilic DScAD. In addition, the average rates of reduction of VS and the production of biogas in thermophilic DScAD were higher by 6.88% and 16.4%, respectively, than were those in mesophilic DScAD. The inhibitory effects of ammonia, H 2 S, and volatile fatty acids (VFAs) on methane production was not clear from either of the digesters, although, apparently, their concentrations did fluctuate. This fluctuation could be attributed to the self-adaptation of the microbial well. However, digestion that was more stable and faster was observed under thermophilic conditions compared with that under mesophilic conditions. Based on our results, the optimum operational parameters to improve FW treatment and achieve higher energy yields could be determined, expanding the application of DScAD in treating organic wastes.

Energy is essential for industrial production. Because of the past abundance of low-cost energy, historically, the rate of social progress among industrial societies has not been limited by energy availability. Energy cost has not been significant when compared with no energy use. Mechanisation of agriculture, increased use of electrical appliances in the domestic sector and rapid industrialisation to meet the demand of exponentially growing population have resulted in an energy crisis. The raised fossil fuel prices and the environmental factors playing the dominant role in implementation of large scale projects, such as hydro, thermal and nuclear, have aggravated the problem further. In this context, an integrated energy plan for a country seems essential for ecologically sound development of a region. An integrated plan includes strategies to: • improve the efficiencies of end use devices and/or conversion equipment in all sectors; • optimise energy sources (end use matching); • maximise the use of renewable resources; • balance the exploitation of biomass energy resources; and • discourage the use of depletable resources. Conservation through improvement of the efficiencies of end use devices is one of the most effective ways to provide immediate relief for the energy problem. This helps to maintain economic growth and social progress of a region. Environmental problems, resource depletion and growing demand of energy in the state/region make it increasingly imperative that we use energy as efficiently as possible, and planners should take note of this untapped resource. The potential for improved energy efficiency is great, and a substantial part of that potential could be realised in the course of events. The industrial sector constitutes a major consumer of commercial energy. Improvement of energy efficiency in the industrial sector would result in a slower rate of energy growth. A secure energy supply is the major concern of most industrialists. It is, thus, necessary to examine industrial energy use and the economy. The analyses of consumption patterns and the assessment of feasible energy conservation possibilities show that the potential for energy conservation in the industrial sector and in all sectors is substantial. The barriers identified to tap this potential are a lack of information on specific measures and options for achieving energy conservation, lack of capital for schemes involving technology upgrading and efficiency improvements, pricing policies which deviate from rational tariffs and the inadequacy of institutional arrangements for promoting energy conservation in different sectors of the economy. In this regard, research should be sponsored to develop system designs, cost and pricing policies, problems related to system interconnection with public utilities and an assessment of potential energy savings, and research into methods of matching energy resources to work requirements, rather than vice versa, for improved efficiency. It is essential for the planning machinery to foster the integrated approach in energy planning of a region. This paper discusses an attempt made by us to illustrate the industrial energy scene in Karnataka and reveals the possibilities of energy conservation. Analysis of the energy consumption data of Karnataka and India shows that the per capita consumption of energy is low (compared with 56 countries in the world), while for the industrial sector, energy per state domestic product (SDP comparable to GDP) is at least 10–20 times higher than that of industrialised countries. This implies inefficiency in energy utilisation. Detailed investigation of the industrial sector through analysis of the Specific Energy Consumption (SEC)—industry wise and yearly for a seven-year period—reveals that about 27.72% of energy could be saved in the industrial sector. This, when quantified, accounts for savings of 1541 million kWh per year in Karnataka, which is equivalent to the power output of 300 MW (Mega Watts) electric power generating station (hydro/thermal).

Abstract The paper is focusing on a shell and plate heat exchanger of a novel absorption refrigeration system. The system is composed of two vacuum vessels connected together with a steam channel and one heat exchanger is located in each vessel. The first heat exchanger is called reactor where working fluid and salt exist and the second heat exchanger or evaporator/condenser (C/E) is where only water exists. The propylene glycol-based (PG) heat transfer fluid is used on the shell side of both heat exchangers as the media to exchange the heat between boilers and reactor in one vessel and between cold environment and condenser/evaporator in another vessel. An experimental test rig was built to investigate the performance of the evaporator/condenser heat exchanger. Then, a three-dimensional (3D) Computational Fluid Dynamics (CFD) model was developed. The experimental result was then used to validate the numerical model developed by using Ansys/Fluent software. A parametric study has been intended to find a more appropriate design for the heat exchanger in order to increase heat transfer performance. Results of the parametric study demonstrated that the cooling performance is doubled by increasing the diameter of the plate from 0.14 m to 0.2 m. In addition, to obtain the maximum heat transfer performance, Reynolds number and distance between plates should be 9 and 0.5 m, respectively. Two correlations have been developed for the outlet temperature and cooling power of the heat exchanger which are functions of heat transfer coefficient. The results of this study can be of vital importance for improving the cooling power of the system, remarkably.