Search results for: low-grade energy source
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 4045

Search results for: low-grade energy source

3115 Evaluating Spectral Relationships between Signals by Removing the Contribution of a Common, Periodic Source A Partial Coherence-based Approach

Authors: Antonio Mauricio F. L. Miranda de Sá

Abstract:

Partial coherence between two signals removing the contribution of a periodic, deterministic signal is proposed for evaluating the interrelationship in multivariate systems. The estimator expression was derived and shown to be independent of such periodic signal. Simulations were used for obtaining its critical value, which were found to be the same as those for Gaussian signals, as well as for evaluating the technique. An Illustration with eletroencephalografic (EEG) signals during photic stimulation is also provided. The application of the proposed technique in both simulation and real EEG data indicate that it seems to be very specific in removing the contribution of periodic sources. The estimate independence of the periodic signal may widen partial coherence application to signal analysis, since it could be used together with simple coherence to test for contamination in signals by a common, periodic noise source.

Keywords: Partial coherence, periodic input, spectral analysis, statistical signal processing.

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3114 A Critical Survey of Reusability Aspects for Component-Based Systems

Authors: Arun Sharma, Rajesh Kumar, P. S. Grover

Abstract:

The last decade has shown that object-oriented concept by itself is not that powerful to cope with the rapidly changing requirements of ongoing applications. Component-based systems achieve flexibility by clearly separating the stable parts of systems (i.e. the components) from the specification of their composition. In order to realize the reuse of components effectively in CBSD, it is required to measure the reusability of components. However, due to the black-box nature of components where the source code of these components are not available, it is difficult to use conventional metrics in Component-based Development as these metrics require analysis of source codes. In this paper, we survey few existing component-based reusability metrics. These metrics give a border view of component-s understandability, adaptability, and portability. It also describes the analysis, in terms of quality factors related to reusability, contained in an approach that aids significantly in assessing existing components for reusability.

Keywords: Components, Customizability, Reusability, and Observability.

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3113 Integrated Waste-to-Energy Approach: An Overview

Authors: Tsietsi J. Pilusa, Tumisang G. Seodigeng

Abstract:

This study evaluates the benefits of advanced waste management practices in unlocking waste-to-energy opportunities within the solid waste industry. The key drivers of sustainable waste management practices, specifically with respect to packaging waste-to-energy technology options are discussed. The success of a waste-to-energy system depends significantly on the appropriateness of available technologies, including those that are well established as well as those that are less so. There are hard and soft interventions to be considered when packaging an integrated waste treatment solution. Technology compatibility with variation in feedstock (waste) quality and quantities remains a key factor. These factors influence the technology reliability in terms of production efficiencies and product consistency, which in turn, drives the supply and demand network. Waste treatment technologies rely on the waste material as feedstock; the feedstock varies in quality and quantities depending on several factors; hence, the technology fails, as a result. It is critical to design an advanced waste treatment technology in an integrated approach to minimize the possibility of technology failure due to unpredictable feedstock quality, quantities, conversion efficiencies, and inconsistent product yield or quality. An integrated waste-to-energy approach offers a secure system design that considers sustainable waste management practices.

Keywords: Emerging markets, evaluation tool, interventions, waste treatment technologies.

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3112 Modeling the Hybrid Battery/Super-Storage System for a Solar Standalone Microgrid

Authors: Astiaj Khoramshahi, Hossein Ahmadi Danesh Ashtiani, Ahmad Khoshgard, Hamidreza Damghani, Leila Damghani

Abstract:

Solar energy systems using various storages are required to be evaluated based on energy requirements and applications. Also, modeling and analysis of storage systems are necessary to increase the effectiveness of combinations of these systems. In this paper, analysis based on the MATLAB software has been analyzed to evaluate the response of the hybrid energy system considering various technologies of renewable energy and energy storage. In the present study, three different simulation scenarios are presented. Simulation output results using software for the first scenario show that the battery is effective in smoothing the overall power demand to the consumer studied during a day, but temporary loads on the grid with high frequencies, effectively cannot be canceled due to the limited response speed of battery control. Simulation outputs for the second scenario using the energy storage system show that sudden changes in demand power are paved by super saving. The majority of these sudden changes in power demand are caused by sewing consumers and receiving variable solar power (due to clouds passing through the solar array). Simulation outputs for the third scenario show the effects of the hybrid system for the same consumer and the output of the solar array, leading to the smallest amount of power demand fed into the grid, as well as demand at peak times. According to the "battery only" scenario, the displacement technique of the peak load has been significantly reduced.

Keywords: Storage system, super storage, standalone, microgrid.

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3111 Corporate Social Responsibility in an Experimental Market

Authors: Nikolaos Georgantzis, Efi Vasileiou

Abstract:

We present results from experimental price-setting oligopolies in which green firms undertake different levels of energy-saving investments motivated by public subsidies and demand-side advantages. We find that consumers reveal higher willingness to pay for greener sellers’ products. This observation in conjunction to the fact that greener sellers set higher prices is compatible with the use and interpretation of energy-saving behaviour as a differentiation strategy. However, sellers do not exploit the resulting advantage through sufficiently high price-cost margins, because they seem trapped into “run to stay still” competition. Regarding the use of public subsidies to energy-saving sellers we uncover an undesirable crowding-out effect of consumers’ intrinsic tendency to support green manufacturers. Namely, consumers may be less willing to support a green seller whose energy-saving strategy entails a direct financial benefit. Finally, we disentangle two alternative motivations for consumer’s attractions to pro-social firms; first, the self-interested recognition of the firm’s contribution to the public and private welfare and, second, the need to compensate a firm for the cost entailed in each pro-social action. Our results show the prevalence of the former over the latter.

Keywords: Corporate social responsibility, energy savings, public good, experiments, vertical differentiation, altruism.

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3110 Investigation of Heat Loss in Ethanol-Water Distillation Column with Direct Vapour Recompression Heat Pump

Authors: Christopher C. Enweremadu, Hilary L. Rutto

Abstract:

Vapour recompression system has been used to enhance reduction in energy consumption and improvement in energy effectiveness of distillation columns. However, the effects of certain parameters have not been taken into consideration. One of such parameters is the column heat loss which has either been assumed to be a certain percent of reboiler heat transfer or negligible. The purpose of this study was to evaluate the heat loss from an ethanol-water vapour recompression distillation column with pressure increase across the compressor (VRCAS) and compare the results obtained and its effect on some parameters in similar system (VRCCS) where the column heat loss has been assumed or neglected. Results show that the heat loss evaluated was higher when compared with that obtained for the column VRCCS. The results also showed that increase in heat loss could have significant effect on the total energy consumption, reboiler heat transfer, the number of trays and energy effectiveness of the column.

Keywords: Compressor, distillation column, heat loss, vapourrecompression.

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3109 The Risk Factors Associated with Under-Five Mortality in Lesotho Using the 2009 Lesotho Demographic and Health Survey

Authors: T. Motsima

Abstract:

The under-5 mortality rate is high in sub-Saharan Africa with Lesotho being amongst the highest under-5 mortality rates in the world. The objective of the study is to determine the factors associated with under-5 mortality in Lesotho. The data used for this analysis come from the nationally representative household survey called the 2009 Lesotho Demographic and Health Survey. Odds ratios produced by the logistic regression models were used to measure the effect of each independent variable on the dependent variable. Female children were significantly 38% less likely to die than male children. Children who were breastfed for 13 to 18 months and those who were breastfed for more than 19 months were significantly less likely to die than those who were breastfed for 12 months or less. Furthermore, children of mothers who stayed in Quthing, Qacha’s Nek and Thaba Tseka ran the greatest risk of dying. The results suggested that: sex of child, type of birth, breastfeeding duration, district, source of energy and marital status were significant predictors of under-5 mortality, after correcting for all variables.

Keywords: Under-5 mortality, risk factors, millennium development goals, breastfeeding, logistic regression.

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3108 Simulation of Thermal Storage Phase Change Material in Buildings

Authors: Samira Haghshenaskashani, Hadi Pasdarshahri

Abstract:

One of the potential and effective ways of storing thermal energy in buildings is the integration of brick with phase change materials (PCMs). This paper presents a two-dimensional model for simulating and analyzing of PCM in order to minimize energy consumption in the buildings. The numerical approach has been used with the real weather data of a selected city of Iran (Tehran). Two kinds of brick integrated PCM are investigated and compared base on outdoor weather conditions and the amount of energy consumption. The results show a significant reduction in maximum entering heat flux to building about 32.8% depending on PCM quantity. The results are analyzed by various temperature contour plots. The contour plots illustrated the time dependent mechanism of entering heat flux for a brick integrated with PCM. Further analysis is developed to investigate the effect of PCM location on the inlet heat flux. The results demonstrated that to achieve maximum performance of PCM it is better to locate PCM near the outdoor.

Keywords: Building, Energy Storage, PCM, Phase Change Material

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3107 Link Availability Estimation for Modified AOMDV Protocol

Authors: R. Prabha, N. Ramaraj

Abstract:

Routing in adhoc networks is a challenge as nodes are mobile, and links are constantly created and broken. Present ondemand adhoc routing algorithms initiate route discovery after a path breaks, incurring significant cost to detect disconnection and establish a new route. Specifically, when a path is about to be broken, the source is warned of the likelihood of a disconnection. The source then initiates path discovery early, avoiding disconnection totally. A path is considered about to break when link availability decreases. This study modifies Adhoc On-demand Multipath Distance Vector routing (AOMDV) so that route handoff occurs through link availability estimation.

Keywords: Mobile Adhoc Network (MANET), Routing, Adhoc On-demand Multipath Distance Vector routing (AOMDV), Link Availability.

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3106 Climate Adaptive Building Shells for Plus-Energy-Buildings, Designed on Bionic Principles

Authors: Andreas Hammer

Abstract:

Six peculiar architecture designs from the Frankfurt University will be discussed within this paper and their future potential of the adaptable and solar thin-film sheets implemented facades will be shown acting and reacting on climate/solar changes of their specific sites. The different aspects, as well as limitations with regard to technical and functional restrictions, will be named.  The design process for a “multi-purpose building”, a “high-rise building refurbishment” and a “biker’s lodge” on the river Rheine valley, has been critically outlined and developed step by step from an international studentship towards an overall energy strategy, that firstly had to push the design to a plus-energy building and secondly had to incorporate bionic aspects into the building skins design. Both main parameters needed to be reviewed and refined during the whole design process. Various basic bionic approaches have been given [e.g. solar ivy TM, flectofin TM or hygroskin TM, which were to experiment with, regarding the use of bendable photovoltaic thin film elements being parts of a hybrid, kinetic façade system.

Keywords: Energy-strategy, photovoltaic in building skins, bionic and bioclimatic design, plus-energy-buildings, solar gain, the harvesting façade, sustainable building concept, high-efficiency building skin, climate adaptive Building Shells (CABS).

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3105 The Effect of Size, Thickness, and Type of the Bonding Interlayer on Bullet Proof Glass as per EN 1063

Authors: Rabinder Singh Bharj, Sandeep Kumar

Abstract:

This investigation presents preparation of sample and  analysis of results of ballistic impact test as per EN 1063 on the size,  thickness, number, position, and type of the bonding interlayer  Polyvinyl Butyral, Poly Carbonate and Poly Urethane on bullet proof  glass. It was observed that impact energy absorbed by bullet proof  glass increases with the increase of the total thickness from 33mm to  42mm to 51mm for all the three samples respectively. Absorption  impact energy is greater for samples with more number of bonding  interlayers than with the number of glass layers for uniform increase  in total sample thickness. There is no effect on the absorption impact  energy with the change in position of the bonding interlayer. 

Keywords: Absorbed energy, bullet proof glass, laminated glass, safety glass.

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3104 Transparent and Solution Processable Low Contact Resistance SWCNT/AZONP Bilayer Electrodes for Sol-Gel Metal Oxide Thin Film Transistor

Authors: Su Jeong Lee, Tae Il Lee, Jung Han Kim, Chul-Hong Kim, Gee Sung Chae, Jae-Min Myoung

Abstract:

The contact resistance between source/drain electrodes and semiconductor layer is an important parameter affecting electron transporting performance in the thin film transistor (TFT). In this work, we introduced a transparent and the solution prossable single-walled carbon nanotube (SWCNT)/Al-doped ZnO nano particle (AZO NP) bilayer electrodes showing low contact resistance with indium-oxide (In2O3) sol gel thin film. By inserting low work function AZO NPs into the interface between the SWCNTs and the In2O3 which has a high energy barrier, we could obtain an electrical Ohmic contact between them. Finally, with the SWCNT-AZO NP bilayer electrodes, we successfully fabricated a TFT showing a field effect mobility of 5.38 cm2/V·s at 250°C.

Keywords: Single-walled carbon nanotube (SWCNT), Al-doped ZnO (AZO) nanoparticle, contact resistance, Thin-film transistor (TFT).

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3103 Adaptive Design of Large Prefabricated Concrete Panels Collective Housing

Authors: Daniel M. Muntean, Viorel Ungureanu

Abstract:

More than half of the urban population in Romania lives today in residential buildings made out of large prefabricated reinforced concrete panels. Since their initial design was made in the 1960’s, these housing units are now being technically and morally outdated, consuming large amounts of energy for heating, cooling, ventilation and lighting, while failing to meet the needs of the contemporary life-style. Due to their widespread use, the design of a system that improves their energy efficiency would have a real impact, not only on the energy consumption of the residential sector, but also on the quality of life that it offers. Furthermore, with the transition of today’s existing power grid to a “smart grid”, buildings could become an active element for future electricity networks by contributing in micro-generation and energy storage. One of the most addressed issues today is to find locally adapted strategies that can be applied considering the 20-20-20 EU policy criteria and to offer sustainable and innovative solutions for the cost-optimal energy performance of buildings adapted on the existing local market. This paper presents a possible adaptive design scenario towards sustainable retrofitting of these housing units. The apartments are transformed in order to meet the current living requirements and additional extensions are placed on top of the building, replacing the unused roof space, acting not only as housing units, but as active solar energy collection systems. An adaptive building envelope is ensured in order to achieve overall air-tightness and an elevator system is introduced to facilitate access to the upper levels.

Keywords: Adaptive building, energy efficiency, retrofitting, residential buildings, smart grid.

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3102 Batteryless DCM Boost Converter for Kinetic Energy Harvesting Applications

Authors: Andrés Gomez-Casseres, Rubén Contreras

Abstract:

In this paper, a bidirectional boost converter operated in Discontinuous Conduction Mode (DCM) is presented as a suitable power conditioning circuit for tuning of kinetic energy harvesters without the need of a battery. A nonlinear control scheme, composed by two linear controllers, is used to control the average value of the input current, enabling the synthesization of complex loads. The converter, along with the control system, is validated through SPICE simulations using the LTspice tool. The converter model and the controller transfer functions are derived. From the simulation results, it was found that the input current distortion increases with the introduced phase shift and that, such distortion, is almost entirely present at the zero-crossing point of the input voltage.

Keywords: Average current control, boost converter, electrical tuning, energy harvesting.

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3101 Asymmetric and Kind of Bracing Effects on Steel Frames Under Earthquake Loads

Authors: Mahmoud Miri, Soliman Maramaee

Abstract:

Because of architectural condition and structure application, sometimes mass source and stiffness source are not coincidence, and the structure is irregular. The structure is also might be asymmetric as an asymmetric bracing in plan which leads to unbalance distribution of stiffness or because of unbalance distribution of the mass. Both condition lead to eccentricity and torsion in the structure. The deficiency of ordinary code to evaluate the performance of steel structures against earthquake has been caused designing based on performance level or capacity spectrum be used. By using the mentioned methods it is possible to design a structure that its behavior against different earthquakes be predictive. In this article 5- story buildings with different percentage of asymmetric which is because of stiffness changes and kind of bracing (x and chevron bracing) have been designed. The static and dynamic nonlinear analysis under three acceleration recording has been done. Finally performance level of the structure has been evaluated.

Keywords: Asymmetric, irregular, seismic analysis, torsion.

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3100 Temperature Effect on the Mechanical Properties of Pd3Rh and PdRh3 Ordered Alloys

Authors: J. Davoodi , J. Moradi

Abstract:

The aim of this research was to calculate the mechanical properties of Pd3Rh and PdRh3 ordered alloys. The molecular dynamics (MD) simulation technique was used to obtain temperature dependence of the energy, the Yong modulus, the shear modulus, the bulk modulus, Poisson-s ratio and the elastic stiffness constants at the isobaric-isothermal (NPT) ensemble in the range of 100-325 K. The interatomic potential energy and force on atoms were calculated by Quantum Sutton-Chen (Q-SC) many body potential. Our MD simulation results show the effect of temperature on the cohesive energy and mechanical properties of Pd3Rh as well as PdRh3 alloys. Our computed results show good agreement with the experimental results where they have been available.

Keywords: Pd-Rh alloy; Mechanical properties; Moleculardynamics simulation

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3099 MPC of Single Phase Inverter for PV System

Authors: Irtaza M. Syed, Kaamran Raahemifar

Abstract:

This paper presents a model predictive control (MPC) of a utility interactive (UI) single phase inverter (SPI) for a photovoltaic (PV) system at residential/distribution level. The proposed model uses single-phase phase locked loop (PLL) to synchronize SPI with the grid and performs MPC control in a dq reference frame. SPI model consists of boost converter (BC), maximum power point tracking (MPPT) control, and a full bridge (FB) voltage source inverter (VSI). No PI regulators to tune and carrier and modulating waves are required to produce switching sequence. Instead, the operational model of VSI is used to synthesize sinusoidal current and track the reference. Model is validated using a three kW PV system at the input of UI-SPI in Matlab/Simulink. Implementation and results demonstrate simplicity and accuracy, as well as reliability of the model.

Keywords: Matlab/Simulink, Model Predictive Control, Phase Locked Loop, Single Phase Inverter, Voltage Source Inverter.

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3098 Energy Separation Mechanism in Uni-Flow Vortex Tube Using Compressible Vortex Flow

Authors: Hiroshi Katanoda, Mohd Hazwan bin Yusof

Abstract:

A theoretical investigation from the view point of gas-dynamics and thermodynamics was carried out, in order to clarify the energy separation mechanism in a viscous compressible vortex, as a primary flow element in a uni-flow vortex tube. The mathematical solutions of tangential velocity, density and temperature in a viscous compressible vortical flow were used in this study.It is clear that a total temperature in the vortex core falls well below that distant from the vortex core in the radial direction, causing aregion with higher total temperature,compared to the distant region,peripheral to the vortex core.

Keywords: Energy separation mechanism, theoretical analysis, vortex tube, vortical flow.

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3097 Fast Prototyping for Atmospheric Plasma Sources Integration into Air Hand Dryers

Authors: Abdel Majid Kassir, Joël Sonnard, Ludovic Roulin, Martine Baudin, Gilles Courret, Wolfram Manuel Brück

Abstract:

Motivated by the current COVID-19 pandemic and the need to find alternative methods to contain and battle it, the purpose of this innovative project is to conceive a disinfection module equipped with a cold atmospheric plasma source. Such a plasma source was developed for a potential integration into pulsed air hand dryers. This type of plasma is known for its ability to generate reactive oxygen and nitrogen species that initiate bio-molecular reactions involved in bacterial and viral deactivation mechanisms. This study shows how additive manufacturing helped accelerate the prototyping of a nozzle allowing the preservation of the plasma flow from circulation cells and external interferences in the discharge’s surrounding.

Keywords: Cold atmospheric plasma, hand disinfection, hand sanitization, bacterial and viral deactivation, plasma chemistry.

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3096 Star-Hexagon Transformer Supported UPQC

Authors: Yash Pal, A.Swarup, Bhim Singh

Abstract:

A new topology of unified power quality conditioner (UPQC) is proposed for different power quality (PQ) improvement in a three-phase four-wire (3P-4W) distribution system. For neutral current mitigation, a star-hexagon transformer is connected in shunt near the load along with three-leg voltage source inverters (VSIs) based UPQC. For the mitigation of source neutral current, the uses of passive elements are advantageous over the active compensation due to ruggedness and less complexity of control. In addition to this, by connecting a star-hexagon transformer for neutral current mitigation the over all rating of the UPQC is reduced. The performance of the proposed topology of 3P-4W UPQC is evaluated for power-factor correction, load balancing, neutral current mitigation and mitigation of voltage and currents harmonics. A simple control algorithm based on Unit Vector Template (UVT) technique is used as a control strategy of UPQC for mitigation of different PQ problems. In this control scheme, the current/voltage control is applied over the fundamental supply currents/voltages instead of fast changing APFs currents/voltages, thereby reducing the computational delay. Moreover, no extra control is required for neutral source current compensation; hence the numbers of current sensors are reduced. The performance of the proposed topology of UPQC is analyzed through simulations results using MATLAB software with its Simulink and Power System Block set toolboxes.

Keywords: Power-factor correction, Load balancing, UPQC, Voltage and Current harmonics, Neutral current mitigation, Starhexagon transformer.

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3095 Open Source Implementation of M-Learning for Primary School in Malaysia

Authors: Saipunidzam Mahamad, Mohammad Noor Ibrahim, Mohamad Izzriq Ab Malek Foad, ShakirahMohd Taib

Abstract:

With the proliferation of the mobile device technologies, mobile learning can be used to complement and improve traditional learning problems. Both students and teachers need a proper and handy system to monitor and keep track the performance of the students. This paper presents an implementation of M-learning for primary school in Malaysia by using an open source technology. It focuses on learning mathematics using handheld devices for primary schools- students aged 11 and 12 years old. Main users for this system include students, teachers and the administrator. This application suggests a new mobile learning environment with mobile graph for tracking the students- progress and performance. The purpose of this system is not to replace traditional classroom but to complement the learning process. In a testing conducted, students who used this system performed better in their examination.

Keywords: M-Learning, Automated Mobile Graph.

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3094 Piezoelectric Power Output Predictions Using Single-Phase Flow to Power Flow Meters

Authors: Umar Alhaji Mukhtar, Abubakar Mohammed El-jummah

Abstract:

This research involved the utilization of fluid flow energy to predict power output using Lead Zirconate Titanate (PZT) piezoelectric stacks. The aim of this work is to extract energy from a controlled level of pressure fluctuation in single-phase flow which forms a part of the energy harvesting technology that powers flow meters. A device- Perspex box was developed and fixed to 50.8 mm rig to induce pressure fluctuation in the flow. An experimental test was carried out using the single-phase water flow in the developed rig in order to measure the power output generation from the piezoelectric stacks. 16 sets of experimental tests were conducted to ensure the maximum output result. The acquired signal of the pressure fluctuation was used to simulate the expected electrical output from the piezoelectric material. The results showed a maximum output voltage of 12 V with an instantaneous output power of 1 µW generated, when the pressure amplitude is 2.6 kPa at a frequency of 2.4 Hz.

Keywords: Energy harvesting, experimental test, perspex rig, pressure fluctuation.

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3093 Automated User Story Driven Approach for Web-Based Functional Testing

Authors: Mahawish Masud, Muhammad Iqbal, M. U. Khan, Farooque Azam

Abstract:

Manual writing of test cases from functional requirements is a time-consuming task. Such test cases are not only difficult to write but are also challenging to maintain. Test cases can be drawn from the functional requirements that are expressed in natural language. However, manual test case generation is inefficient and subject to errors.  In this paper, we have presented a systematic procedure that could automatically derive test cases from user stories. The user stories are specified in a restricted natural language using a well-defined template.  We have also presented a detailed methodology for writing our test ready user stories. Our tool “Test-o-Matic” automatically generates the test cases by processing the restricted user stories. The generated test cases are executed by using open source Selenium IDE.  We evaluate our approach on a case study, which is an open source web based application. Effectiveness of our approach is evaluated by seeding faults in the open source case study using known mutation operators.  Results show that the test case generation from restricted user stories is a viable approach for automated testing of web applications.

Keywords: Automated testing, natural language, user story modeling, software engineering, software testing, test case specification, transformation and automation, user story, web application testing.

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3092 Comparative Exergy Analysis of Ammonia-Water Rankine Cycles and Kalina Cycle

Authors: Kyoung Hoon Kim

Abstract:

This paper presents a comparative exergy analysis of ammonia-water Rankine cycles with and without regeneration and Kalina cycle for recovery of low-temperature heat source. Special attention is paid to the effect of system parameters such as ammonia mass fraction and turbine inlet pressure on the exergetical performance of the systems. Results show that maximum exergy efficiency can be obtained in the regenerative Rankine cycle for high turbine inlet pressures. However, Kalina cycle shows better exergy efficiency for low turbine inlet pressures, and the optimum ammonia mass fractions of Kalina cycle are lower than Rankine cycles.

Keywords: Ammonia-water, Rankine cycle, Kalina cycle, exergy, exergy destruction, low-temperature heat source.

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3091 Thermal Comfort and Energy Saving Evaluation of a Combined System in an Office Room Using Displacement Ventilation

Authors: A. Q. Ahmed, S. Gao

Abstract:

In this paper, the energy saving and human thermal comfort in a typical office room are investigated. The impact of a combined system of exhaust inlet air with light slots located at the ceiling level in a room served by displacement ventilation system is numerically modelled. Previous experimental data are used to validate the Computational Fluid Dynamic (CFD) model. A case study of simulated office room includes two seating occupants, two computers, two data loggers and four lamps. The combined system is located at the ceiling level above the heat sources. A new method of calculation for the cooling coil load in Stratified Air Distribution (STRAD) system is used in this study. The results show that 47.4% energy saving of space cooling load can be achieved by combing the exhaust inlet air with light slots at the ceiling level above the heat sources.

Keywords: Air conditioning, Displacement ventilation, Energy saving, Thermal comfort.

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3090 The Impact of Large-Scale Wind Energy Development on Islands’ Interconnection to the Mainland System

Authors: Marina Kapsali, John S. Anagnostopoulos

Abstract:

Greek islands’ interconnection (IC) with larger power systems, such as the mainland grid, is a crucial issue that has attracted a lot of interest; however, the recent economic recession that the country undergoes together with the highly capital intensive nature of this kind of projects have stalled or sifted the development of many of those on a more long-term basis. On the other hand, most of Greek islands are still heavily dependent on the lengthy and costly supply chain of oil imports whilst the majority of them exhibit excellent potential for wind energy (WE) applications. In this respect, the main purpose of the present work is to investigate −through a parametric study which varies both in wind farm (WF) and submarine IC capacities− the impact of large-scale WE development on the IC of the third in size island of Greece (Lesbos) with the mainland system. The energy and economic performance of the system is simulated over a 25-year evaluation period assuming two possible scenarios, i.e. S(a): without the contribution of the local Thermal Power Plant (TPP) and S(b): the TPP is maintained to ensure electrification of the island. The economic feasibility of the two options is investigated in terms of determining their Levelized Cost of Energy (LCOE) including also a sensitivity analysis on the worst/reference/best Cases. According to the results, Lesbos island IC presents considerable economic interest for covering part of island’s future electrification needs with WE having a vital role in this challenging venture.

Keywords: Electricity generation cost, levelized cost of energy, mainland grid, wind energy rejection.

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3089 A K-Means Based Clustering Approach for Finding Faulty Modules in Open Source Software Systems

Authors: Parvinder S. Sandhu, Jagdeep Singh, Vikas Gupta, Mandeep Kaur, Sonia Manhas, Ramandeep Sidhu

Abstract:

Prediction of fault-prone modules provides one way to support software quality engineering. Clustering is used to determine the intrinsic grouping in a set of unlabeled data. Among various clustering techniques available in literature K-Means clustering approach is most widely being used. This paper introduces K-Means based Clustering approach for software finding the fault proneness of the Object-Oriented systems. The contribution of this paper is that it has used Metric values of JEdit open source software for generation of the rules for the categorization of software modules in the categories of Faulty and non faulty modules and thereafter empirically validation is performed. The results are measured in terms of accuracy of prediction, probability of Detection and Probability of False Alarms.

Keywords: K-Means, Software Fault, Classification, ObjectOriented Metrics.

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3088 Passive Cooling of Building by using Solar Chimney

Authors: Insaf Mehani, N. Settou

Abstract:

Natural ventilation is an important means to improve indoor thermal comfort and reduce the energy consumption. A solar chimney system is an enhancing natural draft device, which uses solar radiation to heat the air inside the chimney, thereby converting the thermal energy into kinetic energy. The present study considered some parameters such as chimney width and solar intensity, which were believed to have a significant effect on space ventilation. Fluent CFD software was used to predict buoyant air flow and flow rates in the cavities. The results were compared with available published experimental and theoretical data from the literature. There was an acceptable trend match between the present results and the published data for the room air change per hour, ACH. Further, it was noticed that the solar intensity has a more significant effect on ACH.

Keywords: Solar chimney, numerical simulation

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3087 Influence Analysis of Pelamis Wave Energy Converter Structure Parameters

Authors: Liu Shengnan, Sun Liping, Zhu Jianxun

Abstract:

Based on three dimensional potential flow theory and hinged rigid body motion equations, structure RAOs of Pelamis wave energy converter is analyzed. Analysis of numerical simulation is carried out on Pelamis in the irregular wave conditions, and the motion response of structures and total generated power is obtained. The paper analyzes influencing factors on the average power including diameter of floating body, section form of floating body, draft, hinged stiffness and damping. The optimum parameters are achieved in Zhejiang Province. Compared with the results of the pelamis experiment made by Glasgow University, the method applied in this paper is feasible.

Keywords: Pelamis, Hinge, Floating multibody, Wave energy

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3086 Plasma Arc Burner for Pulverized Coal Combustion

Authors: Gela Gelashvili, David Gelenidze, Sulkhan Nanobashvili, Irakli Nanobashvili, George Tavkhelidze, Tsiuri Sitchinava

Abstract:

Development of new highly efficient plasma arc combustion system of pulverized coal is presented. As it is well-known, coal is one of the main energy carriers by means of which electric and heat energy is produced in thermal power stations. The quality of the extracted coal decreases very rapidly. Therefore, the difficulties associated with its firing and complete combustion arise and thermo-chemical preparation of pulverized coal becomes necessary. Usually, other organic fuels (mazut-fuel oil or natural gas) are added to low-quality coal for this purpose. The fraction of additional organic fuels varies within 35-40% range. This decreases dramatically the economic efficiency of such systems. At the same time, emission of noxious substances in the environment increases. Because of all these, intense development of plasma combustion systems of pulverized coal takes place in whole world. These systems are equipped with Non-Transferred Plasma Arc Torches. They allow practically complete combustion of pulverized coal (without organic additives) in boilers, increase of energetic and financial efficiency. At the same time, emission of noxious substances in the environment decreases dramatically. But, the non-transferred plasma torches have numerous drawbacks, e.g. complicated construction, low service life (especially in the case of high power), instability of plasma arc and most important – up to 30% of energy loss due to anode cooling. Due to these reasons, intense development of new plasma technologies that are free from these shortcomings takes place. In our proposed system, pulverized coal-air mixture passes through plasma arc area that burns between to carbon electrodes directly in pulverized coal muffler burner. Consumption of the carbon electrodes is low and does not need a cooling system, but the main advantage of this method is that radiation of plasma arc directly impacts on coal-air mixture that accelerates the process of thermo-chemical preparation of coal to burn. To ensure the stability of the plasma arc in such difficult conditions, we have developed a power source that provides fixed current during fluctuations in the arc resistance automatically compensated by the voltage change as well as regulation of plasma arc length over a wide range. Our combustion system where plasma arc acts directly on pulverized coal-air mixture is simple. This should allow a significant improvement of pulverized coal combustion (especially low-quality coal) and its economic efficiency. Preliminary experiments demonstrated the successful functioning of the system.

Keywords: Coal combustion, plasma arc, plasma torches, pulverized coal.

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