Cover

Aims and Scope
Editorial Board

1. Sustainability of an energy conversion system in Canada involving large-scale integrated hydrogen production using solid fuels

Nirmal V. Gnanapragasam, Bale V. Reddy, Marc A. Rosen

Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa ON, L1H 7K4, Canada.

Abstract: The sustainability of a large-scale hydrogen production system is assessed qualitatively. The system uses solid fuels and aims to increase the sustainability of the energy system in Canada through the use of alternative energy forms. The system involves significant technology integration, with various energy conversion processes (e.g., gasification, chemical looping combustion, anaerobic digestion, combustion power cycles-electrolysis and solar-thermal convertors) interconnected to increase the utilization of solid fuels as much as feasible in a sustainable manner within cost, environmental and other constraints. The qualitative analysis involves ten different indicators for each of the three dimensions of sustainability: ecology, sociology and technology, applied to each process in the system and assessed based on a ten-point quality scale. The results indicate that biomasses have better sustainability than coals while newer secondary processes are essential for primary conversion to be sustainable, especially when using coals. Also, new developments in CO₂ use (for algae-to-oil and commercial applications) and storage will in time help improve sustainability.

Volume 2, Issue 1, 2011, pp.1-38.

2. CFD and comparisons for a pump as turbine: Mesh reliability and performance concerns

O. Fecarotta¹, A. Carravetta¹ , H. M. Ramos²

1 Engineering Faculty - Università degli Studi di Napoli Federico II, Italy.

2 Civil Engineering Department and CEHIDRO, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001, Lisbon, Portugal.

Abstract: The need for saving energy in water supply systems has become one of the main concerns of system managers and it will become more important in a near future. New strategies must be developed and implemented in the major energy consumption systems like those for water supply. In drinking pipe systems the use of Pressure Reducing Valves (PRV) as a dissipative device is the common way to uniform the pressure control through a localised head loss. The use of micro-turbines or pumps operating as turbines seem to be an alternative technical and environmental available solution to either control the pressure as well as to produce energy. Pumps as turbines (PAT) could be a convenient choice, but a deep study of the machine in different operating conditions is necessary in order to prevent the water system from ruptures. This paper shows that semi-empirical parametrical models do not generally predict with precision the behaviour of a pump operating as a turbine, while CFD analysis could be a reliable tool to better understand the interaction between the hydromechanical equipment and the flow behaviour. Nevertheless the CFD calculation difficulty is generally very high and the minimum complexity of the CFD calculation mesh has been investigated, in order to perform faster and reliable simulations. Thus CFD calculations have been carried out to predict the turbine behaviour under different flow conditions and the performance curves have been obtained. Some calculations in unsteady state flow regimes have been led to investigate the response of the machine to a sudden discharge changing, as a preliminary study of the behaviour of a turbomachine installed in a water distribution system under water hammer situations.

3. Life cycle assessment of 50 kWp grid connected solar photovoltaic (SPV) system in India

A. F. Sherwani¹, J. A. Usmani², Varun³, Siddhartha³

1 Department of Mechanical Engineering, Delhi Technological University, Delhi 110042, India.

2 Department of Mechanical Engineering, Jamia Millia Islamia, New Delhi 110025, India.

3 Mechanical Engineering Department, National Institute of Technology, Hamirpur 177005, India.

Abstract: Life cycle assessment (LCA) of a 50 kW solar photovoltaic (SPV) system which is situated at Bazak (Bhatinda) in Punjab state (India) has been presented. Among all the components in the SPV system, PV modules are energetically and environmentally very expensive elements. The energy pay-back time (EPBT) was found to be 1.85 years and the normalized greenhouse gas (GHG) emissions was evaluated as 55.7 g-CO₂/kWhe. These results have also been compared with the other SPV electricity generation systems.

4. Ecological performance of a generalized irreversible Carnot heat engine with complex heat transfer law

Jun Li, Lingen Chen, Fengrui Sun

Postgraduate School, Naval University of Engineering, Wuhan 430033, P. R. China.

Abstract: The optimal ecological performance of a generalized irreversible Carnot heat engine with the losses of heat-resistance, heat leakage and internal irreversibility, in which the transfer between the working fluid and the heat reservoirs obeys a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law is derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the power and entropy production rate of the heat engine. The effects of heat transfer laws and various loss terms are analyzed. The obtained results include those obtained in many literatures.

5. Review and analysis of renewable energy perspectives in Serbia

Charikleia Karakosta, Haris Doukas, Maria Flouri, Stamatia Dimopoulou, Alexandra G. Papadopoulou, John Psarras

National Technical University of Athens, School of Electrical and Computer Engineering, Management & Decision Support Systems Lab (NTUA-EPU), 9, Iroon Polytechniou str., 157 80, Athens, Greece.

Abstract: Nowadays, Serbia needs to disengage from the broad use of fossil fuels and turn to the “attractive” Renewable Energy Sources (RES) for energy production, since the Kyoto Protocol ratification, so as to resolve systematically the problem of energy demand. In addition, research indicates that Serbia is a country with high potential and favourable conditions for RES energy production, as the country’s potential could supply almost half of its primary energy needs. The paper provides an overview of Serbia’s energy sector status quo, so as to emphasize the necessity for RES implementation in order to balance the country’s energy deficit. The aim is to investigate and present the country’s prospects in the RES sector, revealing the proven RES potential and pointing out that the unexploited RES potential together with an adequately well structured energy sector would create great possibilities and conditions for a new market.

6. Finite time exergoeconomic performance optimization of a thermoacoustic heat engine

Xuxian Kan^1,2,  Lingen Chen¹,  Fengrui Sun¹,  Feng Wu^1,2

1 Postgraduate School, Naval University of Engineering, Wuhan 430033, P. R. China.

2 School of Science, Wuhan Institute of Technology, Wuhan 430073, P. R. China.

Abstract: Finite time exergoeconomic performance optimization of a generalized irreversible thermoacoustic heat engine with heat resistance, heat leakage, thermal relaxation, and internal dissipation is investigated in this paper. Both the real part and the imaginary part of the complex heat transfer exponent change the optimal profit rate versus efficiency relationship quantitatively. The operation of the generalized irreversible thermoacoustic engine is viewed as a production process with exergy as its output. The finite time exergoeconomic performance optimization of the generalized irreversible thermoacoustic engine is performed by taking profit rate as the objective. The analytical formulas about the profit rate and thermal efficiency of the thermoacoustic engine are derived. Furthermore, the comparative analysis of the influences of various factors on the relationship between optimal profit rate and the thermal efficiency of the generalized irreversible thermoacoustic engine is carried out by detailed numerical examples. The optimal zone on the performance of the thermoacoustic heat engine is obtained by numerical analysis. The results obtained herein may be useful for the selection of the operation parameters for real thermoacoustic heat engines.

7. Biochemical characterization of thermophilic lignocellulose degrading enzymes and their potential for biomass bioprocessing

Vasudeo Zambare¹, Archana Zambare¹, Kasiviswanath Muthukumarappan², Lew P. Christopher¹

1 Center for Bioprocessing Research & Development, South Dakota School of Mines and Technology, Rapid City 57701, SD, USA.

2 Center for Bioprocessing Research & Development, South Dakota State University, Brookings 57007, SD, USA.

Abstract: A thermophilic microbial consortium (TMC) producing hydrolytic (cellulolytic and xylanolytic) enzymes was isolated from yard waste compost following enrichment with carboxymethyl cellulose and birchwood xylan. When grown on 5% lignocellulosic substrates (corn stover and prairie cord grass) at 60C, the thermophilic consortium produced more xylanase (up to 489 U/l on corn stover) than cellulase activity (up to 367 U/l on prairie cord grass). Except for the carboxymethyl cellulose-enriched consortium, thermo-mechanical extrusion pretreatment of these substrates had a positive effect on both activities with up to 13% and 21% increase in the xylanase and cellulase production, respectively. The optimum temperatures of the crude cellulase and xylanase were 60C and 70C with half-lives of 15 h and 18 h, respectively, suggesting higher thermostability for the TMC xylanase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crude enzyme exhibited protein bands of 25-77 kDa with multiple enzyme activities containing 3 cellulases and 3 xylanases. The substrate specificity declined in the following descending order: avicel>birchwood xylan>microcrystalline cellulose>filter paper>pine wood saw dust>carboxymethyl cellulose. The crude enzyme was 77% more active on insoluble than soluble cellulose. The Km and Vmax values were 36.49 mg/ml and 2.98 U/mg protein on avicel (cellulase), and 22.25 mg/ml and 2.09 U/mg protein, on birchwood xylan (xylanase). A total of 50 TMC isolates were screened for cellulase and xylanase secretion on agar plates. All single isolates showed significantly lower enzyme activities when compared to the thermophilic consortia. This is indicative of the strong synergistic interactions that exist within the thermophilic microbial consortium and enhance its hydrolytic capabilities. It was further demonstrated that the thermostable enzyme-generated lignocellulosic hydrolyzates can be fermented to bioethanol by a recombinant strain of Escherichia coli. This could have important implications in the enzymatic breakdown of lignocellulosic biomass for the establishment of a robust and cost-efficient process for production of cellulosic ethanol. To the best of our knowledge, this work represents the first report in literature on biochemical characterization of lignocellulose-degrading enzymes from a thermophilic microbial consortium.

8. Effect of injection timing on combustion and performance of a direct injection diesel engine running on Jatropha methyl ester

S. Jindal

Mechanical Engineering Department, College of Technology & Engineering, Maharana Pratap University of Agriculture and Technology, Udaipur -313001, India.

Abstract: The present study aims at evaluation of effect of injection timing on the combustion, performance and emissions of a small power diesel engine, commonly used for agriculture purpose, running on pure biodiesel, prepared from Jatropha (Jatropha curcas) vegetable oil. The effect of varying injection timing was evaluated in terms of thermal efficiency, specific fuel consumption, power and mean effective pressure, exhaust temperature, cylinder pressure, rate of pressure rise and the heat release rate. It was found that retarding the injection timing by 3 degrees enhances the thermal efficiency by about 8 percent.

9. An overview of load demand and price forecasting methodologies

George Kourtis, Ioannis Hadjipaschalis, Andreas Poullikkas

Electricity Authority of Cyprus, P.O. Box 24506, 1399 Nicosia, Cyprus.

Abstract: In this work, an overview of the various methodologies developed in recent years for short, mid and long term load and price forecasting is carried out. In the analysis the advantages and disadvantages of each method are introduced, together with the factors that influencing the different types of forecasting. Unless the effects of these factors are well taken into consideration errors can occur in the forecasting results and that results in increasing operational costs. The analysis indicates that the best suited method for all types of forecasting is artificial neural network, which outperforms better with nonlinear functions and on weekend days or national holidays. If are not to be distinguished from week day data, weekend and national holidays data a good alternative would be an autoregressive integrated moving average based method.

10. Degradation of mixture of phenolic compounds by activated sludge processes using mixed consortia

M. Rajani Rani, D. Sreekanth, V. Himabindu

Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally Hyderabad-500 085, India.

Abstract: This study describes the feasibility of aerobic treatment  of  wastewater having mixed Phenolic compounds (phenol, 2-4dinitrophenol, 2-4dichlorophenol, 4-chlorophenol, 4-nitrophenol) by using 9L lab scale Activated Sludge Process (ASP) at HRTs (Hydraulic Retention Time) varying between  3.0 ,2.5, 2.0, 1.5 and 1 day. Continuous monitoring of parameters like pH, Oxidation Reduction Potential (ORP), Chemical Oxidation Demand (COD) , compound reduction is used to asses the treatment efficiency of ASP. The highest percentage COD  removal and  percentage compound  reduction  of 98% and 99.3% of phenol was observed at 3.0 d HRT respectively. After treatment pollutants are removed in the order of phenol > 4chlorophenol (4CP) > 4nitrophenol (4NP) > 2-4dichlorophenol (2-4DCP) > 2-4 dinitrophenol (2,4DNP). The dissolved oxygen concentration and pH in the activated sludge reactor was found to be 1-3 mg/L and 7-8 respectively. The optimum biomass concentration was 2500-3000 mg/L, whereas the corresponding SVI was found to be around 70mL/g. The morphological characterization of aerobic granules was carried out by using SEM. Thus the results obtained indicate that ASP could be used efficiently for the treatment of wastewater containing mixed phenols.

11. Improving the performance of a hybrid electric vehicle by utilization regenerative braking energy of vehicle

Mohamed Mourad

Automotive and Tractors Department, Faculty of Engineering, Minia University, Egypt.

Abstract: Environmentally friendly vehicles with range and performance capabilities surpassing those of conventional ones require a careful balance among competing goals for fuel efficiency, performance and emissions. It can be recuperated the energy of deceleration case of the vehicle to reuse it to recharge the storage energy of hybrid electric vehicle and increase the state of charge of batteries under the new conditions of vehicle operating in braking phase. Hybrid electric vehicle has energy storage which allows decreasing required peak value of power from prime mover, which is the internal combustion engine. The paper investigates the relationships between the driving cycle phases and the recuperation energy to the batteries system of hybrid electric vehicle. This work describes also a methodology for integrating this type of hybrid electric vehicle in a simulation program. A design optimization framework is then used to find the best position that we can utilize the recuperation energy to recharge the storage batteries of hybrid electric vehicle.

12. Finite-time exergoeconomic performance of an endoreversible Carnot heat engine with complex heat transfer law

Jun Li, Lingen Chen, Fengrui Sun

Postgraduate School, Naval University of Engineering, Wuhan 430033, P. R. China.

Abstract: The finite time exergoeconomic performance of an endoreversible Carnot heat engine with a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law is investigated in this paper. The finite time exergoeconomic performance optimization of the engine is investigated by taking profit optimization criterion as the objective. The focus of this paper is to search the compromised optimization between economics (profit) and the utilization factor (efficiency) for endoreversible Carnot heat engine cycles. The obtained results include those obtained in many literatures and can provide some theoretical guidance for the design of practical heat engines.

13. Role of a biodiesel blend in sustaining the energy and environment as a CI engine fuel

S.Saravanan¹, G.Nagarajan², G.Lakshmi Narayana rao³, S.Sampath⁴

1Department Of Automobile Engineering, Sri Venkateswara College of Engineering, India.

2 Department Of Mechanical Engineering   College of Engineering, Anna University, India.

3 QIS Institute of Technology, Ongole, Andhra Pradesh, India.

4 Department Of Automobile Engineering, Rajalakshmi Engineering College, India.

Abstract: In the present work, biodiesel derived from high free fatty acid (FFA) crude rice bran oil, (CRBO) a non-edible vegetable oil was tested as a fuel in a compression ignition engine in blended form to test its suitability and also its ability to create a sustainable environment. A 4.4 kW direct injection stationary diesel engine was used for experimentation. Biodiesel (crude rice bran oil methyl ester) blend was prepared by mixing 20 % crude rice bran oil methyl ester (CRBME) with 80 % diesel on volume basis. An enhanced thermal oxidation was observed for the CRBME blend which oxidizes most of the UBHC into CO and CO₂. As a result of this, UBHC emission and smoke density were reduced by 28 % and 35 % respectively with a marginal increase in CO and NOx emission than diesel. It was also observed that by blending CRBME with diesel, the brake thermal efficiency of the engine decreased only marginally which ensures the suitability of CRBME blend as a CI engine fuel. Experimental results show almost similar performance in CRBME blend when compared to diesel which strengthens its ability to have a sustainable environment. This research work can be extended to improve the thermal oxidation process which may result in further reduction in CO, UBHC and particulate emission than that of the emissions reported in this paper.

14. Correlation for estimation of hourly solar radiation

A. K. Katiyar, C. K. Pandey

Department of Applied Sciences, Institute of Engineering & Technology, Lucknow-226021, India.

Abstract: As the availability of solar radiation for a place depends upon the climatic conditions of the locality, a correlation for a place may not be suitable for other places of different climatic conditions. Therefore, an attempt has been made to develop a new model to evaluate hourly solar radiation on horizontal surface for Indian locations having different climatic conditions, using least square regression analysis based on the ASHRAE model. For this purpose measured diffuse and global solar radiation data from January 2001 to December 2005 of Ahmedabad, Calcutta, Bombay, Pune and Chennai cities of India have been used. Comparison between the estimated and the measured values shows that the constants derived for Indian locations provide good estimates of hourly solar radiation. The present estimated hourly solar radiation have also been compared with the estimates of the Liu and Jordan [7] and Singh et al [10] models which correlate hourly values and daily global radiation. In order to indicate the performance of the models, the statistical test methods of the mean bias error (MBE), root mean square error (RMSE) and t-test are used.