Showing papers by "Nand Kishor published in 2009"

Adaptive fuzzy model identification to predict the heat transfer coefficient in pool boiling of distilled water

Abstract: In this paper, a modeling technique based on fuzzy system is used to predict the heat transfer coefficient in pool boiling of distilled water. To achieve this, an experimental investigation has been carried out for saturated boiling of distilled water from plain copper heating tube surface at atmospheric and sub-atmospheric pressures. An empirical correlation has been established to predict the boiling heat transfer coefficient. Further, the experimental data has been compared with those determined from the zero-order adaptive fuzzy model with heat flux as input variable. The representation accuracies of the pool boiling heat transfer coefficient for fuzzy model is very high as indicated from the performance index. The prediction performance of zero-order adaptive fuzzy model has also been compared with MATLAB based ANFIS function. Further, the statistical attributes are determined and compared with the experimental data set of pool boiling of distilled water available in open literatures.

Frequency regulation of hybrid renewable energy system for large band wind speed variation

Abstract: A proportional-plus-integral (PI) controlled based small-signal analysis of isolated autonomous hybrid system with different energy storage combinations is presented in this paper. The hybrid systems supplying power to isolated loads comprise of different renewable energy resources such as wind, photovoltaic (PV), fuel cell (FC) and diesel engine generator (DEG) along with the energy storage devices such as flywheel energy storage system (FESS), battery energy storage system (BESS). Large band wind speed based on Van der Hoven's model is also presented in this paper in order to analyze the frequency deviation due to mismatch between power generation and load demand. Further ultracapacitor (UC) as an energy storing element and PI controllers are incorporated in the hybrid system in order to improve the frequency deviation. A comparative assessment for different hybrid systems in the presence of different storage system combinations and PI controller is carried out which reflects the improvements of the deviation in frequency profile in the presence of the ultracapacitors (UC) as compared to other storage elements.

Small-Signal Analysis of Hybrid Distributed Generation System with HVDC-Link and Energy Storage Elements

Abstract: A small-signal analysis of isolated autonomous hybrid system with high voltage direct current link (HVDC) or high voltage alternating current (HVAC) line for different energy storage combinations is proposed in this paper. The hybrid systems supplying power to isolated loads comprise of different renewable energy resources such as wind, photovoltaic (PV), fuel cell (FC) and diesel engine generator (DEG) along with the energy storage devices such as flywheel energy storage system (FESS), battery energy storage system (BESS).Ultracapacitor (UC) is incorporated as an energy storing element in order to improve the hybrid system performance. A comparative assessment for deviation in frequency profile for different hybrid systems in the presence of different storage system combinations is carried out which reflects the improvements of the deviation in frequency profile in the presence of the ultracapacitors (UC) as compared to other storage elements.

G K clustering approach to determine optimal number of clusters for Wireless Sensor Networks

Abstract: Wireless Sensor Networks (WSN) are resource constrained system Efficient use of resources especially, energy is most important for their life extension Clustering is a well known technique for achieving high scalability and efficient resource allocation in WSN One of the fundamental issues in cluster based networks is to determine the optimal number of clusters with the objective of minimizing the energy consumption Considering its importance, a GK clustering approach is used to determine the optimal number of clusters The study considers the deployment of 100 nodes in 100×100 m2 area for both random and random uniform distributions