S. Kumaravel

Bio: S. Kumaravel is an academic researcher from National Institute of Technology Calicut. The author has contributed to research in topics: Photovoltaic system & Microgrid. The author has an hindex of 10, co-authored 63 publications receiving 402 citations.

An Optimal Stand-Alone Biomass/Solar-PV/Pico-Hydel Hybrid Energy System for Remote Rural Area Electrification of Isolated Village in Western-Ghats Region of India

Abstract: Biomass based hybrid energy system is utilized for the electrification of villages, especially in developing countries like India. Hybrid Energy System (HES) components, feasibility study, and cost analysis are presented in this paper for a remote area Kakkavayal, a forest region in Kerala, India. A water stream at 25 m height has been identified at Kakkavayal by the Forest Department of Kerala. The village has been marked to study hourly measured meteorological and load data for a period of time. The performance of the proposed hybrid system is determined on hourly basis and optimum configuration, which can meet the energy demand with minimum cost using the hybrid system design tool HOMER. Parametric analysis indicates that with 2 kW solar PV, 15 kW pico-hydel, and 5 kW biomass gasifier generator together with five numbers of 12 V, 200 Ah of battery storage to meet the primary load demand of 56 kWh/d and 17 kWh/d (scaled annual average) of deferrable load. From the simulation, the cost of energy is found...

High Step-Up Gain DC–DC Converter With Switched Capacitor and Regenerative Boost Configuration for Solar PV Applications

Abstract: Because of cost, size, and weight, the transformer is the primary burden in grid-connected solar PV-system and it decreases the whole system efficiency. In order to avoid the use of a transformer, a high step-up gain dc-dc converter is proposed by combining the switched capacitor and regenerative boost (SCRB) configuration in this brief. In classic boost type and derived converters, the device stresses and losses associated with the converter are high and result in lower efficiency. In the proposed converter, the SCRB operations take place simultaneously using lossless passive components and a minimum number of semiconductor devices. Thereby, it drastically increases the dc-voltage gain and enhances efficiency. In addition, it also dominates with fewer ripple content, which helps to elongate the lifetime of devices and suppress the electromagnetic interference. This brief describes detailed steady-state waveforms and various modes of operation under continuous conduction mode and discontinuous conduction mode. This brief also presents the performances of the proposed converter and compares with conventional converters characteristics. A 500 W experimental model has been built to validate the operation and confirms the theoretical waveforms with experimental results. The maximum efficiency of 95.60% is obtained at 480 W for the proposed converter.

Dual input–dual output DC–DC converter for solar PV/battery/ultra-capacitor powered electric vehicle application

Abstract: Utilisation of more than one energy source in the electric vehicle (EV) ensures the reliable riding of the vehicle without range anxieties. Solar PV, battery and ultra-capacitor are viable sources to power the EV. A novel dual input–dual output dc–dc converter is proposed for the integration of the above sources for the EV application. The converter can be used to transfer power between the input sources and loads/utility grid/other EVs. The proposed converter can be operated in ten different modes using the same structure by controlling the appropriate switches. The equivalent circuits with the analytical waveforms of significant modes of operation of the converter are discussed in this study. The output equations of all ten modes are derived. The theoretical analysis of the converter is verified experimentally using a 1 kW laboratory prototype and the observed experimental results are shown in the study. A strategy for selecting a mode according to the status of the vehicle, grid, battery etc. is developed. The loss breakdown analysis and efficiency profile of the converter are presented. Finally, the performance comparisons of the proposed converter with the reported converters are carried out in terms of component counts, a number of operating modes etc.

Optimization of biohydrogen production by Enterobacter species using artificial neural network and response surface methodology

Abstract: Optimization studies on fermentative hydrogen production were investigated using a facultative bacteria namely, Enterobacter species (MTCC 7104). The present study emphasizes the application of mathematical tools such as response surface methodology (RSM) and artificial neural network (ANN) to predict the maximum yield of hydrogen from the optimized carbon and nitrogen source. The key components such as glucose, initial pH, xylose, tryptone, yeast extract, sucrose, and peptone were screened using the Plackett-Burman design. Furthermore, rotatable central composite design and analysis of variance were adopted to investigate the interactive effect of the significant variables (xylose concentration, initial pH, and peptone concentration). Maximum experimental hydrogen yield of 1.94 mol H2/mol xylose was achieved at the optimal points predicted by the RSM. Modeling ability of ANN and RSM has also been evaluated on predicting the maximum hydrogen yield with the estimated values of root mean square error (RMSE), multiple correlation coefficients (R2), and standard error of prediction (SEP). The estimated values of RMSE, R2, and SEP for ANN model and RSM model confirm that fitness and prediction accuracy of ANN model were higher when compared to RSM model. Energy conversion efficiency and energy recovery analysis were performed for hydrogen production process using xylose as the source material.

Review of software tools for hybrid renewable energy systems

Abstract: Hybrid energy systems are being utilized for supplying electrical energy in urban, rural and remote areas to overcome the intermittence of solar and wind resources. A hybrid renewable energy system incorporates two or more electricity generation options based on renewable energy or fossil fuel unit. The techno-economic analysis of the hybrid system is essential for the efficient utilization of renewable energy resources. Due to multiple generation systems, hybrid system analysis, is quite complex and requires to be analyzed thoroughly. This requires software tools for the design, analysis, optimization, and economic viability of the systems. In this paper, 19 softwares with their main features and current status are presented. The softwares studied are HOMER, Hybrid2, RETScreen, iHOGA, INSEL, TRNSYS, iGRHYSO, HYBRIDS, RAPSIM, SOMES, SOLSTOR, HySim, HybSim, IPSYS, HySys, Dymola/Modelica, ARES, SOLSIM, and HYBRID DESIGNER. The research work related to hybrid systems carried out using these softwares at different locations worldwide is also reviewed. The main objective of the paper is to provide the current status of these softwares to provide basic insight for a researcher to identify and utilize suitable tool for research and development studies of hybrid systems. The capabilities of different softwares are also highlighted. The limitations, availability and areas of further research have also been identified.

Computational optimization techniques applied to microgrids planning: A review

Abstract: Microgrids are expected to become part of the next electric power system evolution, not only in rural and remote areas but also in urban communities. Since microgrids are expected to coexist with traditional power grids (such as district heating does with traditional heating systems), their planning process must be addressed to economic feasibility, as a long-term stability guarantee. Planning a microgrid is a complex process due to existing alternatives, goals, constraints and uncertainties. Usually planning goals conflict each other and, as a consequence, different optimization problems appear along the planning process. In this context, technical literature about optimization techniques applied to microgrid planning have been reviewed and the guidelines for innovative planning methodologies focused on economic feasibility can be defined. Finally, some trending techniques and new microgrid planning approaches are pointed out.

Comparative study of stand-alone and hybrid solar energy systems suitable for off-grid rural electrification: A review

Abstract: Global environmental concerns, increasing energy demands and developments in renewable energy technologies present a new possibility to implement renewable energy sources. Solar energy is the most prominent among renewable sources, as it is an inexhaustible resource and its exploitation has thus far been ecologically friendly. The potential amount of solar energy is considerably greater than current worldwide energy demands. Solar energy has been developing more rapidly than the other renewable energy sources for the last few decades. The best way to harvest the sun’s power is photovoltaic (PV) technology. This paper presents a study on solar energy in the form of a stand-alone and hybrid power generation system used to electrify off-grid locations. The stand-alone solar-PV system developed here is intended to be used to power a single house or a small community and it also functions as a mini-grid, generating power in places where adequate solar radiation is available throughout the year. However, many places throughout the world experience unsteady amounts of solar radiation and in those places, a hybrid solar-PV system is the most efficient solution for electrification. The main benefit of the hybrid system is that the weakness of one source is covered by the other source. This paper also presents some comparative case studies, project examples and demonstrations of stand-alone solar and hybrid solar systems implemented at various locations throughout the world over the last twelve years.

Hybrid wind/photovoltaic energy system developments: Critical review and findings

Abstract: Renewable energy sources are certain to play a key role in the future energy generation due to the rapid depletion of conventional sources of energy. The solar and wind energy are the major renewable energy sources which have the potential to meet the energy crisis to some extent. However, such sources when explored independently are not completely reliable because of the unpredictable nature. Whereas their use as hybrid energy systems seems to be more reliable and cost effective, due to the complementary nature of these two resources. In this paper an attempt has been made to discuss a systematic review related to hybrid PV/wind energy systems with battery storage. The work as presented in the manuscript will help the researchers to explore such hybrid energy systems for further improvements in terms of designing, analyzing and integrating such systems into the power network.