International Journal of Renewable Energy Technology (15 papers in press)
Novel model for defining electricity tariffs using residential load profile characterisation
by Sima Davarzani, Ioana Pisica, Laurentiu Lipan
Abstract: In recent years, great attention towards enabling future smart grid functionalities in distribution networks creates significant changes in electricity load profiles. These changes require a new advanced paradigm in electricity pricing and tariffs definition aiming to increase the potential of responsiveness demand. This paper aims to propose a new model for designing residential electricity tariffs using their load profile clustering and characterization, taking into account social, technical and educational factors alongside the financial incentives. The methodology is based on estimation of the potential of demand responsiveness to dynamic pricing over time for different cluster of households with similar electricity consumption patterns. In this regard, different time of use pricing bands has been considered and compared with fixed price tariffs. Moreover, a baseline demand for each cluster of households has been determined based on the elasticity of demand to different static tariffs. The results show that the proposed model can provide distribution network operators (DNOs) and suppliers with a basic and general outline of defining more effective dynamic pricing schemes that reflect intermittent nature of residential demand.
Keywords: Demand response; electricity market; electricity tariffs; price elasticity; residential load profile.
Kinetic and Thermodynamic Modelling Studies of Enhanced Mixed Animal Wastes Biomethanization Co-digested with Pineapple Fruit Waste and Chicken Rumen
by Oluwafunmilayo A. Aworanti, Samuel E. Agarry, Oladipupo O. Ogunleye
Abstract: This work investigated the effects of feed/inoculums ratio, temperature and agitation speed on biomethanization of mixed animal wastes (cattle dung, pig dung, and poultry droppings) for enhanced biogas/biomethane production. The biomethanization experiments were carried out in anaerobic digesters at different process variables of feed/inoculums ratio (1:1, 1:2, 1:3, 2:1 and 3:1), temperature (25 - 60oC), and agitation speed (30 - 70 rpm). The digesters were incubated for 70 days. The results showed positive influence of feed/inoculum ratio, temperature and agitation speed on cumulative biogas yield, biomethane content and start-up time of biomethanization. Agitation speed of 30 to 70 rpm generally enhanced cumulative biogas yield in the range of 5.3 to 31.3% as well as the biomethane content in the range of 4.3 to 26.1% in comparison with biomethanization without agitation. Minimum cumulative biogas yield and biomethane content was respectively obtained with feed/inoculum ratio of 1:1, temperature of 25
Keywords: Animal waste; Biogas; Biomethane Content; Process variables; Kinetics; Thermodynamics.
An Adaptive Limiter for Unbalanced Operation of Doubly Fed Induction Generator Based Wind Energy System
by Tanaya Datta, Prabodh Bajpai
Abstract: Actual limits on parameters of Type-3Wind generation unit i.e. Doubly
Fed Induction Generator (DFIG) are in terms of peak values of phase quantities
but enforcement of limits in DFIG is achieved by positive and negative sequence
controllers. The limits are generally enforced considering the scenario where
positive and negative sequence vectors are collinear. However, this restricts the
capability regions of the DFIG. The objective of this paper is to implement
an adaptive limiter which conforms to all possible variations in phase angle
between positive and negative sequence components. This will improve the range
of operation irrespective of the level of unbalance of the connected distribution
system. An adaptive limiter for voltage and current, considering different PWM
(Pulse Width Modulation) techniques for the Voltage Source Converters (VSC), is
implemented for unbalanced operation of DFIG and compared with generalized
Keywords: Doubly Fed Induction Generator; Limiters; Operating limits; Pulse Width Modulation; Second harmonic oscillations; Unbalanced distribution system.
Review on Maximum Power Point Tracking Techniques For Photovoltaic Arrays Working under Uniform/Non-Uniform Insolation Level
by Bhavnesh Kumar, S.K. Jha, Tarun Kumar
Abstract: Photovoltaic (PV) energy is one of most prominent renewable and non polluting energy to fulfill the rising demand of electricity. But, availability of sun for limited time span and low conversion efficiency of solar cells overshadow its advantages. Generally, for the maximum exploitation of power from the photovoltaic array, a maximum power point tracking (MPPT) controller is used in these systems. Different methods are available in the literature for development of MPPT controller. Majority of MPPT controllers are designed for the single peak powervoltage (P-V) characteristics. During partial shading on PV array the resultant PV curve exhibits multiple peaks consisting of Local maxima and Global maxima. During partial shading, the conventional methods of MPPT may not converge to the global maxima. In this paper, an exhaustive literature review is presented on the MPPT techniques available for PV array operating under various operating conditions.
Keywords: maximum power point tracking; photovoltaic array; partial shading.
Modelling and analysis of solar dryer cum water heater through CFD and analytical methods
by Subramaniam Senthilkumar, M. Natarajan, S. Duraikumar
Abstract: Active utilization of solar energy for heating and drying is need of the day for several domestic and commercial applications. Modelling and analysis of a typical solar crop dryer cum water heater has been presented in this paper. A thin layered bed solar dryer with water heater was modelled in Solid Works software. CFD analysis is carried out to evaluate thermal and air flow performance. A performance analysis by analytical modelling was conceded by energy balance equations for working fluids and solar dryer components. The results of analytical method and CFD analysis were associated. The optimum performance parameters of the system were arrived with varied flow rate data.
Keywords: Modelling; Simulation; CFD; performance analysis; solar energy; solar dryer; water heater.
Determination of Optimal Tilt Angles in some Selected Cities of Nigeria for Maximum Extractable Solar Energy
by Temitope Raphael Ayodele, Ayodeji Samson Ogunjuyigbe, Samuel Oladeji
Abstract: In this paper, optimum tilt angles are determined for some selected cities for optimal performance of solar panels. The study also compares the effects of placing solar panel on optimum tilt angle to that of horizontal position in terms of extractable solar power as well as the cost of energy. The results reveal that optimum tilt angle changes between 0o and 42o throughout the year. The optimum value is found to be 0o during the raining seasons (i.e. April-August). The findings also show that the optimum tilt angle increases in the range of 5 o to 42o during the dry seasons (September-March) reaching its maximum value in the month of December in all the locations. The extractable power on optimum inclined surface increase in the range of 2.5-9 % compared to horizontal surface while the cost of electricity reduces by 6-9% when solar panel is placed on optimally inclined surface.
Keywords: Global solar radiation; Optimum tilt angle; solar panel; angle of declination; Nigeria.
Special Issue on: ECRES2017 Advances in Renewable Energy Systems
Optimal placement and sizing of DSTATCOM using Firefly Algorithm in the Distribution System
by Padmavathi K, Sudha K. R
Abstract: The electric power distribution system must be intended to operate and deliver acceptable level of electrical energy to consumers. Distribution Static Compensator (DSTATCOM) is a custom power device implemented in the distribution system to improve the power quality. This paper presents the optimal size and placement of DSTATCOM in the distribution system by using Firefly Algorithm (FA). Minimization of power loss and minimization of installation cost of DSTATCOM are considered as the Objective Function (OF), where the voltage and current limits of the buses are chosen as the optimization constraints. The performance of the proposed methodology using FA is demonstrated on IEEE 33 bus and 69 bus Radial Distribution Systems using MATLAB software. Backward/Forward sweep algorithm is used for load flow analysis of radial distribution system. The efficacy of the proposed methodology using Firefly algorithm (FA) is compared with the results obtained by using Immune Algorithm (IA).
Keywords: Backward/Forward load flow; DSTATCOM; Radial Distribution System; Firefly Algorithm (FA); Power Quality; Voltage Source Converter (VSC);.
Analysis of a Heat Pump Assisted Solar Water Heating System Using TRNSYS Program
by Salih COSKUN, Gamze Kandirmiş, Cüneyt Tunçkal
Abstract: The use of renewable energy systems for hot water has become increasingly widespread. Especially, traditional solar hot water system (SDHW) is an important system for the use of renewable energy sources. This system consists of a solar collector, a circulating pump and a water tank in which an electrical heater is placed. In this system, while water is heated by sun in summer or hot days, it is heated by electric heaters in winter, or cold days. So efficiency of this system is low in winter because of very high electric consumption. This problem can be solved using heat pump instead of electric heaters. In this study, mounting a water to water heat pump, an auxiliary tank and a circulating pump in the SDHW system, a heat pump assisted solar domestic hot water system (HP_SDHW) was designed to increase efficiency. A SDHW and a HP_SDHW were modeled and simulated depending on time using TRNSYS (Transient system simulation) program. An analysis was performed through the year for both systems at SARAJEVO conditions. The amounts of energy consumed for both systems and how much of the energy needed to heat the water is met by the sun (solar fraction) were calculated and system performances were compared. As a result of the annual analysis, it was found that the HP_SDHW system consumes approximately 40% less electricity than the traditional SDHW system. The solar fraction of the HP_SDHW (%67) was found higher than the SDHW system (%46) for SARAJEVO Conditions.
Keywords: Heat pump; solar energy; renewable energy; TRNSYS; simulation; domestic hot water.
General situation of wind energy source in Turkey and wind turbine technologies
by Yusuf Alper KAPLAN
Abstract: The increasing the need for new energy sources is a result of the rapidly increasing global population and consumption of fossil fuels. In order to achieve more efficient use of wind energy in Turkey, the establishment of more efficient wind turbines with new technologies and the widespread use of wind-generating systems is inevitable. The regional distribution of the wind energy potential of Turkey, the regional and general usage rates and the policies followed in wind energy subjects are worth investigating. Besides, it is very important to discover new wind fields, to calculate the capacities of these areas by technical analysis methods and finally to use them. Recently, wind power capacity has increased dramatically in Turkey and accompanying that, the wind turbines that produce it have become more affordable and more efficient for wind energy producers. Wind turbine technologies have been mentioned in general and generator models used in wind turbines have been examined. Consequently, wind energy resource isnt efficiently used in Turkey and how the using of wind energy potential is improved is generally discussed.
Keywords: DFIG; Energy Policy; Energy Structure; PMSG; Renewable Energy; Wind Energy; Wind turbine generator.
Theoretical and Experimental analysis of glazed serpentine tube flat plate collector for effluent evaporation
by Deepak Sonawane, Vinod Tungikar
Abstract: In this paper theoretical and experimental study of serpentine tube flat plate collector for evaporation of water in the effluent is presented. The performance of the flat plate collector depends on various factors including the collector construction and the arrangement of the system. The prototype working model has been fabricated to prove the feasibility and viability of the evaporation system. Results obtained show that the evaporation rate of water in the effluent increases, with the increase in solar radiation, wind velocity and decrease in mass flow rate of effluent, relative humidity and concentration of the effluent. The evaporation rate of effluent in the single cover serpentine tube flat plate collector is found to increase by 41 % compared to the solar pan and 16% to the single cover FRP flat plate collector.
Keywords: Solar Energy; Effluent; Evaporation; Glazing; Serpentine tube flat plate collector.
Power electronic converters without electrolytic capacitors
by Alex Van Den Bossche, Salim Haddad, Mourad Mordjaoui
Abstract: Power electronic converters may have a quite long lifetime, but some applications such as converters for automotive and photovoltaic could even desire a longer life. One of the elements to increase the lifetime of converters is to avoid electrolytic capacitors. They can be replaced by metalized film capacitors or ceramic capacitors. A lot of converter types can be re-designed to use them, but it influences the way of designing, as a lower capacitance value is used. Electrolytic capacitors are one of the elements that reduce the lifetime of power electronic converters gradually an adapted design can avoid that electrolytic capacitors have to be used in converters. A range of examples can be shown from fractions of watts up to Gigawatt. The purpose is to give an overview of topologies, not to discuss them in detail: for example gate drive circuits, single and three-phase converters where film capacitors are used in the DC link and high voltage DC converters. These techniques are useful to prolong the life of converters and to allow higher ambient temperatures, typical application domains are PV and other grid-connected converters, converters for battery charging and general electric vehicle applications
Keywords: Power electronic converters; electrolytic capacitors; lifetime.
Design and Implementation of a Prototype Hybrid Micro grid Model for Available Weather Conditions
by Srishti Singh, Prerna Gaur, Madhur Kapoor, Sankalp Goel, Satinderpal Singh, Sonali Negi
Abstract: The increasing threat to environment and the consequent depletion of renewable energy resources has led the hybrid energy system to come in forefront. The hybrid energy systems are to be designed to compensate the loss in the renewable resources such as Wind, PV (Photo Voltaic), Thermal energy, Biomass etc. The ultimate goal is to increase the efficiency of hybrid energy system. The complementary nature of PV and Wind hybrid system makes it resourceful, trustworthy and can also act as uninterrupted power supply. A renewable energy model (PV-Wind hybrid integration) can potentially address the energy crisis in the fast developing society. Such decentralized and standalone systems can produce substantial amount of electricity all that at no harm to environment and at a very economical rate. A MATLAB/Simulink based PV-Wind hybrid generation system is developed. The proposed work is aimed at to design and simulate a hybrid model according to the power needs of a test area consisting of around thirty households with 4 kWh/day average household requirement. The simulated study is cross verified with the similar hardware prototype to check feasibility, sustainability and viability of the hybrid model. The weather conditions consisting of Insolation, Day, Time, Temperature, latitude, longitude, Panel angle etc. of the test area have been acquired for hardware purpose. A case study of a state in India is used to develop the proposed model.
Keywords: GA; MPPT; P&O; PV; SEIG; WTIG.
Bioethanol production from sawdust of Colombian pine. Conditions and efficiency
by Rodrigo Andres Sarria-Villa, Jose Antonio Gallo, Martha Paez, Ricardo Benitez-Benitez
Abstract: The growing importance of the transport sector in relation to energy demand underscores the need for action to improve energy efficiency and to develop economically and environmentally viable energy alternatives. Many materials with high cellulose contents are likely to be used as feedstock for the production of biofuels, which are generated as waste by the production processes of the agricultural, forestry and industrial sectors. This paper presents the results of the conditions under which ethanol can be obtained from the sawdust of the forest species Pinus patula and Pinus oocarpa, which were grown in the Cauca Department in Colombia. Highest percentages of cellulose were with 12% of NaOH. The best delignification yields were obtained at 90 minutes and 40 mesh screen. Enzymatic hydrolysis with the fungus Trichoderma viride led to cellobiose and glucose for P. patula and P. oocarpa between 7 and 37% respectively. Particle size of 425
Keywords: Sawdust; Gas Chromatography; Hydrolysis; Ethanol; HPLC.
The effect of non-uniformities in temperature on the performance parameters of an isolated cell photovoltaic module with a compound parabolic concentrator
by Damasen Ikwaba Paul, Mervyn Smyth, Aggelos Zacharopoulos
Abstract: This study investigated the effect of non-uniformities in cell temperature on the open-circuit voltage, short-circuit current, maximum power output and fill factor of each cell in a PV module with 11 isolated cells placed in a compound parabolic concentrator (CPC). To achieve this objective, symmetric CPC and a photovoltaic (PV) module were designed and fabricated. The PV module with and without the CPC were both exposed to a constant solar illumination of 615 W/m2 continuous for 18 minutes. It was found that the temperature for the cells in the PV module without the CPC were almost constant while that with the CPC varied by 20%. Due to non-uniformities in cell temperature, the decrease in open-circuit voltage, maximum power output and fill factor was higher for cells with higher temperature than similar cells with lower temperature. However, the short-circuit current slightly increased with cell temperature.
Keywords: non-uniformity in temperature; cell temperature; temperature coefficient; energy flux distribution; isolated cell PV module; compound parabolic concentrator; CPC; temperature coefficient of the short-circuit current; temperature coefficient of the open-circuit voltage; temperature coefficient of the maximum power output; temperature coefficient of the fill factor.
Special Issue on: Sustainable Energy Technologies
STUDIES ON HYDROGEN FUELLED STATIONARY C. I. ENGINE OPERATED END-UTILITY SYSTEM
by Vinod Singh Yadav, Dilip Sharma, S.L. Soni
Abstract: The refineries turned in a better performance with their cumulative 181 million tones crude throughput, almost 7 per cent more than the previous fiscals achievement and a little over 2 percent of the planned target. The world is presently confronted with the twin crisis of fossil fuel depletion and environmental degradation. Combined residential and commercial energy demand is expected to increase in order to meet the expected increase in electricity demand as the worlds population shall grow and more people shall move to urban areas with access to electricity. The search for an alternative fuel, which promises a pleasant link with sustainable development, energy conservation, management, efficiency, and environmental safeguarding, has become highly noticeable in the present context. rnIn this investigation, fresh air with hydrogen enrichment was used as intake charge in a C. I. engine. Experiments were conducted on a 1-C, 4-S, air-cooled, stationary direct-injection diesel engine (Kirlosker TAF1) with maximum 1500 rpm and maximum 4.4 kW capacity coupled to an electrical generator. The injection timing (17
Keywords: Hydrogen-Enrichment; Injection timing; Flow rate of hydrogen; Performance.