International Journal of Energy


ISSN: 1998-4316
Volume 8, 2014

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

Main Page

Submit a paper | Submission terms | Paper format

 


Volume 8, 2014


Title of the Paper: LNG Regasification System to Enhance the Performance of Gas Turbines and Water Desalination Systems

 

Authors: Asad A. Salem, Emad Hudiab

Pages: 84-90

Abstract: The objective of this research is to propose a new approach in regasification of Liquefied Natural Gas (LNG). In this approach a solar energy powered Liquefied Natural Gas (LNG) regasification system that incorporates a water desalination process utilizing the cold energy available in the LNG. The solar energy is utilized in an air humidification unit, were hot and saturated air is produced. The thermal energy contained in the saturated and hot air is employed by a LNG regasification unit which converts LNG to natural gas (NG). During the regasification process, the hot and saturated air is cooled below the Dew-point temperature producing a sizable amount of fresh water. The proposed system is tested under various conditions of temperatures and relative humidity. The results show that there is a substantial increase in the efficiency of the gas turbines (GT) which translated to the efficiency of the power plant as a result of cooling the air that is fed to the GT. in such approach the regasification heat requirement will be served through concentrating solar power system CSP, a regasification model of 1 Billion SCFD (19000 ton/day) is considered, the expected fresh water production for this proposed model is around 6.5 million liter per day, the produced cold dry air of this proposed regasification technique would enhance the power out-pout of the attached gas turbines. The proposed system is a mix of various technologies and a proposal for the better utilization of energy to generate power.


Title of the Paper: Monitoring and Modelling of Energy Efficiency for Low Energy Testing Houses in Latvian Climate Conditions

 

Authors: Andris Jakovics, Stanislavs Gendelis, Janis Ratnieks, Saule Sakipova

Pages: 76-83

Abstract: Five experimental test buildings (stands) have been built in Riga, Latvia (see Figure 1). They are identical except external walls for which different, mainly regional, building materials have been used. However, projected heat transmittance (U-value) of the walls, floor and ceiling is the same for each test building. Initial moisture influences the relative humidity of indoor air, which can be higher at initial time period when buildings have just been built. As a result the U-values are also very different and cause different heating/cooling energy consumption. Measurements show that critical situation is observed for two test houses (aerated concrete constructions with insulation layer and ceramic block construction with insulation filling) where initial moisture is high and the drying process of external walls is slowly. Results show that the heat demand in cold period for this two test houses are significantly higher than another 3 test stands. Moreover, overheating risks for two “critical” test houses are significantly lower in summer. However, the situation is not normal in that case. Both summer and heating seasons have been analysed and differences between five test houses are discussed in details. Mathematical model to predict air flow velocity and temperature fields are developed and validated.


Title of the Paper: Decline of Active Power Loss and Preservation of Voltage Stability by Hybridization of Cuckoo Search Algorithm with Powell Search

 

Authors: K. Lenin, B. Ravindhranath Reddy

Pages: 71-75

Abstract: In this paper, Hybridization of Cuckoo Search algorithm with Powell Search (HCSPS) is used to solve optimal reactive power problem. Cuckoo search (CS) has been recently projected as a population-based optimization algorithm and it is has so far been efficaciously applied in a variety of fields. The inertia weight of Levy flights is presented to balance the capability of global and local search. The Powell local search method is used to progress the best guesstimate found by the cuckoo search algorithm. The hybridization of cuckoo search algorithm and Powell search technique will deliver a more active trade-off between exploitation and exploration of the search space. The proposed HCSPS has been tested on standard IEEE 57 bus test system and simulation results show clearly the better performance of the proposed algorithm in reducing the real power loss.


Title of the Paper: Large-Scale Energy Storage and Dynamic Performance of the Autonomous Power System in Crete Island: A Review of the Literature

 

Authors: Yiannis A. Katsigiannis, Emmanuel S. Karapidakis, Antonios G. Tsikalakis, Anastasia Katsamaki

Pages: 60-70

Abstract: The autonomous power system of Crete Island is the largest autonomous power system in Greece, accounting for around 5% of total energy demand. The Cretan power system is of particular interest, not only because of its high renewable energy sources (RES) potential, but also due to its specific operating characteristics, including the absence of interconnection, the large number of small capacity conventional plants existence, and its high electricity production costs. Apart from the already apparent and expected benefits of high RES penetration, a variety of parameters that include variation of RES, loss of conventional units, added errors, and complexity in the operating system’s conditions due to increased number of RES plants may also cause significant issues in its stability. Moreover, the technical constraints that are added due to RES technologies operation may lead to a reduction of their absorbed energy by the system, reducing therefore the benefits from their commitment. One way to achieve high penetration from renewable energy is the installation of large scale energy storage units, such as pumped hydro storage (PHS) systems. However, in any case it is essential to maintain the desired dynamic stability and economic operation of the system. This can be only implemented with the design and development of an advanced and intelligent real time power management system. The scope of this paper is to provide the necessary review and evaluation of related literature in these subjects.


Title of the Paper: Three-Level Direct Torque Control Based on Space Vector Modulation of Double Star Synchronous Machine

 

Authors: Elakhdar Benyoussef, Abdelkader Meroufel, Said Barkat

Pages: 53-59

Abstract: This paper presents a direct torque control based on space vector modulation of the salient-pole double star synchronous machine drive fed by two three-level neutral point clamped inverters. This type of inverters has several advantages over the standard two-level inverter, such as a greater number of levels in the output voltage waveforms, less harmonic distortion in voltage and current waveforms and lower switching frequencies. The conventional direct torque control drives utilizing hysteresis comparators suffer from high torque ripple and variable switching frequency. The most common solution to those problems is to use the space vector depends on the reference torque and flux. Simulations results are included to verify the effectiveness of the proposed control method under load disturbances and speed reference variations.


Title of the Paper: Solar-Powered Ultra-Light Aircrafts: An Overview on Power System Technology

 

Authors: P. Guarino, G. L. Cascella, S. Stasi, M. Dassisti, M. Chimienti

Pages: 43-52

Abstract: This paper surveys the proposed solutions for the design of an ultra-light Unmanned Aerial Vehicles, showing the most recent advances in technology for the power system of the design. In particular this paper focuses on the electrical components of the project, showing a brief review of the single objects and their applicability for the design of a Solar-Powered Airplane. The aim of this paper is to collect all the useful information for people who wants to begin a design process for an ultra light aerial vehicle with electric propulsion system and a solar energy conversion source, giving basic information about the state of the art of the UAV projects and the requirements for the power system management elements.


Title of the Paper: Integrating Intelligent Transportation Systems Devices Using Power Line Communication

 

Authors: Cledson A. Sakurai, Claudio L. Marte, Leopoldo R. Yoshioka, Caio F. Fontana

Pages: 36-42

Abstract: The goal of intelligent transportation system (ITS ) is to improve urban mobility in relation to safety , usability , mobility , quality and productivity through the use of information and communication technology and one of the main problems is to ensure that which elements of ITS such as cars, buses, sensors, actuators, lights, among others are exchanging data with them, due to the size of this environment, the infrastructure of communication between the transportation management system (TMS) and ITS components and between ITS components are extremely important in this context, this work proposes the use of communication technologies considered for the smart grid , which is the Power Line Communication (PLC) system, which consists of data communication through the grid network that is available in urban centers , and can even share with the smart grid network. Another characteristic between ITS and Smart Grid is that the booth environment will exchange small data packages, so it is possible to use narrow band technologies. In this paper was considered the evaluation of two initiatives on narrow band PLC, PRIME and G3, which have similar physical layer, and the PRIME privileges the high data rates during favourable conditions and G3 provides better performance on unfavourable conditions. The both projects can be used as a communication data channel for communication between TMS and ITS elements, because this communication requests a low bit rate.


Title of the Paper: An Additional Income of Small Hydropower Plants and a Public Trader

 

Authors: A. Sauhats, R. Varfolomejeva, I. Umbrasko, H. Coban

Pages: 29-35

Abstract: This paper is devoted to consider a use of hydropower of small rivers; the feed-in tariff system for small-scale hydro power plants (SHPP), its disadvantages and opportunities to remove them. Cooperative game theory approach is used for evaluation of possibilities to gain additional income and analysis of regime management of the small-scale hydro power plant. Technical and economical aspects of the issue are observed in the paper. Offered approach is demonstrated on an example with 10 players (9 SHPPs and a public trader). The obtained results demonstrate the validity of the cooperation for obtaining additional income.


Title of the Paper: Avoided CO2 Cost. Case Study for a Conventional Power Plant

 

Authors: Liviu Ruieneanu

Pages: 24-28

Abstract: The paper presents an analysis of a series of different strategies for the decrease of the CO2 emissions produced by a conventional coal power plant. All the strategies were compared in terms of CO2 emissions and the avoided CO2 cost. Very good results were obtained for steam turbine power plants operating in parallel with renewable energy sources. Cogeneration and trigeneration increase the energy quota of the renewable energy sources decreasing the cost of avoided CO2. Another interesting solution analysed here was the post-combustion carbon capture and storage (CCS). CCS has the advantage of a low cost for the avoided CO2 cost combined with almost null CO2 emissions. CCS also ensures a stable operation platform that would not affect the stability of the electrical grid. Lower CO2 emissions are possible when rapid-cycle gas turbine plants are compensating renewable energy sources, but with a higher cost for the avoided CO2.


Title of the Paper: Design of Solar Powered Ultra-light Aircrafts: Realization of a Model and Its Validation

 

Authors: P. Guarino, G. L. Cascella, S. Stasi, M. Dassisti, M. Chimienti

Pages: 16-23

Abstract: In this paper the authors present a model suitable to convert ultralight airplanes propulsion system from endothermic into electric, focusing only on the power management issues, discarding the mechanical and dynamic ones. The model developed represents a tool to correctly size the propulsion and energy management system of ultra-light aircrafts designed for short endurance flights. The authors performed several experiments to validate the model and to verify the efficiency of the designing tool.


Title of the Paper: Firefly Algorithm for Environmental/economic Power Dispatch Including Renewable Energy

 

Authors: Mimoun Younes, Riad Lakhdar Kherfane, Fouad Khodja, Naas Kherfane

Pages: 8-15

Abstract: The ecological concerns about air pollution and global warming are encouraging wider use of clean renewable technologies such as wind and solar energy. In this paper, firefly algorithm is applied to optimize the emission and the overall cost of the classical energy system by including a renewable energy system. Simulation results on the 10 units power system prove the efficiency of this method thus conīŦrming its capacity to solve the environmental/economic power dispatch problem with the renewable energy.


Title of the Paper: Improving Security of Gas Supply in Eastern Baltic Region: LNG Terminal Alternatives

 

Authors: Ando Leppiman, Kati Kõrbe Kaare, Ott Koppel

Pages: 1-7

Abstract: One of the crucial issues in Europe at the moment is securing reliable gas supply. Growing demand for gas has rekindled a debate on gas security of supply due to supply interruptions, increasing gas prices, cross-border bottlenecks and a growing reliance on imports over longer distances. Achieving security of gas supply implies diversifying gas sources, while having enough supply, transportation, and storage capacity to meet demand peaks and supply interruptions. In 2013, the Baltic States and Finland still remain disintegrated from the rest of Europe: their natural gas infrastructure isolates them into “energy islands”. The gas demand in these isolated member states is approximately 10 billion cubic meters of natural gas per year. The third energy package of European Union (EU) proposes a new series of measures to promote competition and create a single European energy market. Estonia, Latvia, Lithuania and Finland now for the first time have a chance to secure their energy independence by connecting their natural gas systems with those of their European allies and evolving them into market-based trading systems. Liquefied natural gas (LNG) is an important energy source that contributes to energy security and diversity, therefore a concept of a regional LNG terminal has been proposed. In this paper the authors give an overview of the current situation and present possible future scenarios with the development of Eastern Baltic regional LNG terminal. In 2014 the decision will be made regarding which of the proposed projects of regional LNG terminal is chosen to be funded by EU as a project of common interest in the trans-European energy networks.