Cover

Aims and Scope
Editorial Board

1. Sensibility study of flooding and drying issues to the operating conditions in PEM fuel cells

F. Brèque¹, J. Ramousse², Y. Dubé¹, K. Agbossou¹, P. Adzakpa¹

1 Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 boulevard des Forges, C.P. 500, Trois-Rivières (Québec), G9A 5H7, Canada.

2 LOCIE - Université de Savoie, Campus scientifique - Savoie Technolac, 73376 Le Bourget du Lac – CEDEX, France.

Abstract: Due to water management issues, operating conditions need to be carefully chosen in order to properly operate fuel cells. Because of the gas consumption along the feeding channels and water production at the cathode, internal cell humidification is highly inhomogeneous. Consequently, operating fuel cells are very often close to critical operating conditions, such as flooding and drying, at least locally. Based on this observation, the critical current, corresponding to internal cell humidification balance (acurate membrane hydration, without excess of water at the electrodes), is deduced from a pseudo-2D model of mass transfer in the cell. Using the model, a parametric sensibility study of the operating conditions is presented to analyze the cell internal humidification. Dead-end and flow-through modes of hydrogen supply are also compared. It is shown that the operating temperature is a key parameter to manage the cell humidification. Moreover, although the oxygen stoichiometric ratio has an effect on cell humidification, this influence is limited and cannot be used alone to adjust the cell humidification. Furthermore, it is shown that in some cases, humidifying the anode inlet gas is of little interest to the internal humidification adjustment. Finally, those results allow to understand the role that each operating parameter can play on the cell internal humidification. Consequently, this study is of a great interest to water management improvement in polymer electrolyte membrane fuel cells.

Volume 1, Issue 1, 2010, pp.1-20.

2. Hybrid energy system evaluation in water supply system energy production: neural network approach

Fábio V. Gonçalves¹, Helena M. Ramos¹, Luisa Fernanda R. Reis²

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

2 Universidade de São Paulo, EESC/USP, Departamento de Hidráulica e Saneamento., Avenida do Trabalhador Sãocarlense, 400, São Carlos-SP, Brazil.

Abstract: Water supply systems are large consumers of energy and the use of hybrid systems for green energy production is this new proposal. This work presents a computational model based on neural networks to determine the best configuration of a hybrid system to generate energy in water supply systems. In this study the energy sources to make this hybrid system can be the national power grid, micro-hydro and wind turbines. The artificial neural network is composed of six layers, trained to use data generated by a model of hybrid configuration and an economic simulator – CES. The reason for the development of an advanced model of forecasting based on neural networks is to allow rapid simulation and proper interaction with hydraulic and power model simulator – HPS. The results show that this computational model is useful as advanced decision support system in the design of configurations of hybrid power systems applied to water supply systems, improving the solutions in the development of its global energy efficiency.

3. Analytical study to minimize the engine exhaust emissions and safe knock limit of CNG powered four-stroke SI engine

Jeewan V. Tirkey, H.N. Gupta, S.K. Shukla

Mechanical Engineering Department,  Institute of Technology, Banaras Hindu University, Varanasi- 221005, India.

Abstract: In this paper, theoretical analysis has been done to minimise engine emissions and safe knock limit by changing some operational and design parameters such as equivalence ratio, spark plug location, compression ratio, and cylinder diameter by using computer simulation model. For this purpose a zero dimensional knock model, two zone combustion model(one in front and one behind the flame front), and gas dynamic model have been incorporated. Subsequently, the Nitric Oxide exhaust emission concentrations have been predicted by using the rate kinetic model in the power cycle and along the exhaust pipes. Furthermore, Carbon Monoxide is computed under chemical equilibrium condition and then empirical adjustment is made for kinetic behaviours based upon experimental results. It is inferred that the value of cylinder pressure data, BMEP, BSFC obtained by using computer simulation model based on theoretical analysis are in closer agreement with those which are obtained by previous studies.

4. Market penetration of biodiesel

Kenneth R. Szulczyk¹, Bruce A. McCarl²

1 Department of Economics, Orbita 3, Suleyman Demirel University, Almaty,  050043  Kazakhstan.

2 Department of Agricultural Economics, 2124 TAMU, Texas A&M University, College Station, Texas, 77843  U.S.A.

Abstract: This research examines in detail the technology and economics of substituting biodiesel for diesel #2. This endeavor examines three areas. First, the benefits of biodiesel are examined, and the technical problems of large-scale implementation. Second, the biodiesel production possibilities are examined for soybean oil, corn oil, tallow, and yellow grease, which are the largest sources of feedstocks for the United States. Examining in detail the production possibilities allows to identity the extent of technological change, production costs, byproducts, and greenhouse gas (GHG) emissions. Finally, a U.S. agricultural model, FASOMGHG was used to predict market penetration of biodiesel, given technological progress, variety of technologies and feedstocks, market interactions, energy prices, and carbon dioxide equivalent prices. FASOMGHG has several interesting results. First, diesel fuel prices have an expansionary impact on the biodiesel industry. The higher the diesel fuel prices, the more biodiesel is produced. However, given the most favorable circumstances, the maximum biodiesel market penetration is 9% in 2030 with a wholesale diesel price of $4 per gallon. Second, the two dominant sources of biodiesel are from corn and soybeans. Sources like tallow and yellow grease are more limited, because they are byproducts of other industries. Third, GHG prices have an expansionary impact on the biodiesel prices, because biodiesel is quite GHG efficient. Finally, U.S. government subsidies on biofuels have an expansionary impact on biodiesel production, and increase market penetration at least an additional 3%.

5. The phenomenon of evaporative cooling from a humid surface as an alternative method for air-conditioning

E. Velasco Gómez, F.C. Rey Martínez, A. Tejero González

Thermal Engineering Group, Department of Energy Engineering and Fluid mechanics, School of Engineering, University of Valladolid, Paseo del Cauce nº 59, 47011 Valladolid, Spain.

Abstract: The phenomenon of evaporative cooling is a common process in nature, whose applications for cooling air are being used since the ancient years. In fact, it meets this objective with a low energy consumption, being compared to the primary energy consumption of other alternatives for cooling, as it is simply based in the phenomenon of reducing the air temperature by evaporating water on it. This process can be an interesting alternative to conventional systems in these applications where no very low temperatures are needed, like the case of air-conditioning during the summer. However, the risk of contamination by legionnaire’s disease, commonly related to evaporative cooling systems, has led in recent years to the substitution of these devices in the industry by less-efficient systems, like the case of cooling towers or evaporative condensers substituted by air-condensing refrigerating processes. Therefore, these systems based in the evaporative cooling are rarely used for cooling buildings. To reduce this risk, evaporative cooling is produced from humid surfaces, in such a way that water evaporates due to the difference of vapor pressure between the surface and the air, and thus minimizing the generation of aerosols, responsible for the spread of legionnaire disease. Aerosols are nevertheless produced in conventional systems where water is sprayed or directly in contact with the stream of air; and the problem worsens if the water, which is recirculated, has been still in any moment or its temperature is adequate for the bacteria proliferation. This paper aims to introduce the thermodynamic basis in which the process is based, as well as the commercial evaporative systems and the problem associated to legionnaire’s disease in this kind of systems. Furthermore, three different experimental devices based in evaporative cooling are described, which have been designed and manufactured in the Thermal Engineering Research Group of the University of Valladolid., describing their characteristics of operation and providing the experimental results obtained during their characterization, for outside air conditions typical of hot and dry summers.

6. Dispersion modeling in assessing air quality of industrial projects under Indian regulatory regime

Amitava Bandyopadhyay

Department of Chemical Engineering, University of Calcutta, 92, A.P.C.Road, Kolkata 700 009, India.

Abstract: Environmental impact assessment (EIA) studies conducted over the years as a part of obtaining environmental clearance in accordance with Indian regulation have been given significant attention towards carrying out Gaussian dispersion modeling for predicting the ground level concentration (GLC) of pollutants, especially for SO₂. Making any adhoc decision towards recommending flue gas desulfurization (FGD) system in Indian fossil fuel combustion operations is not realistic considering the usage of fuel with low sulfur content. Thus a predictive modeling is imperative prior to making any conclusive decision. In the light of this finding, dispersion modeling has been accorded in Indian environmental regulations. This article aims at providing approaches to ascertain pollution potential for proposed power plant operation either alone or in presence of other industrial operations under different conditions. In order to assess the performance of the computational work four different cases were analyzed based on worst scenario. Results obtained through predictions were compared with National Ambient Air Quality Standards (NAAQS) of India. One specific case found to overshoot the ambient air quality adversely in respect of SO₂ and was therefore, suggested to install a FGD system with at least 80 % SO₂ removal efficiency. With this recommendation, the cumulative prediction yielded a very conservative resultant value of 24 hourly maximum GLC of SO₂ as against a value that exceeded well above the stipulated value without considering the FGD system. The computational algorithm developed can therefore, be gainfully utilized for the purpose of EIA analysis in Indian condition.

7. Evaluation of the conversion efficiency of the 180Nm³/h Johansson Biomass Gasifier™

Ntshengedzeni S. Mamphweli, Edson L. Meyer

University of Fort Hare, Institute of Technology, Private bag x 1314, Alice 5700, South Africa.

Abstract: Biomass gasification is the thermochemical conversion of biomass materials into a producer gas, which is a mixture of carbon monoxide, carbon dioxide, methane, hydrogen, nitrogen and water vapour. The 180Nm³/h System Johansson Biomass Gasifier (SJBG) at Eskom research and Innovation Centre is used for research and development initiatives, and also for demonstration purposes. The aim of this research was to investigate the efficiency of the gasifier and. This is done through an analysis of the gas profiles at the gasifier using a custom-built gas and temperature measurement system. Non-Dispersive Infrared gas detection technique is applied to monitor the volume and quality of producer gas. Palladium/Nickel gas sensing is applied to monitor the hydrogen content in the gas stream. Temperature in the gasifier is monitored through the use of type K thermocouples. The gas and temperature sensors are connected to the data logger interfaced to a computer. The heating value of the producer gas was determined from the percentage composition of the combustible gases. Evaluation of the efficiency of this gasifier was done before the installation of a 300Nm³/h at a rural village. The gasifier achieved an efficiency of 75% with an average gas heating value of 6MJ/Nm³.

8. Adsorption characteristics of Ni²⁺ ion onto the diethylenetriaminepentaacetic acid-melamine / polyvinylidene fluoride blended resin

Xiaodan Zhao, Laizhou Song, Jun He, Tingying Wu, Ying Qin

Department of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China.

Abstract: The polyvinylidene fluoride blended resin (DTPA-MA/PVDF) adsorbent prepared by anchoring the chelating agent diethylenetriaminepentaacetic acid (DTPA) to the resin via the amide covalent bond reaction between DTPA and melamine(MA), was used to remove nickel from aqueous solutions. The blended resin was prepared using the combination of solution blending technique and phase inversion process. The blended resin was characterized by Fourier transform infrared spectroscopy (FTIR), ¹³C nuclear magnetic resonance spectroscopy (¹³C NMR), environmental scanning electron microscopy (ESEM) and N₂ adsorption/desorption experiments. The sorption data was fit to linearized adsorption isotherms of the Langmuir, Freundlich, and D-R isotherms models. The batch sorption kinetics was evaluated using pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic reaction models. ΔH° is less than 0, ΔG° is lower than 0, and ΔS° is greater than 0, which shows that the adsorption of Ni(II) by the blended resin is a spontaneous, exothermic process. The adsorption isotherm fits better to the Langmuir isotherm model and the pseudo-second-order kinetics model gives a better fit to the batch sorption kinetics. The adsorption mechanism is assumed to be ion exchange between the nickel ion and the polyamino polycarboxylic acid chelating group of the blended resin.

9. Heating/cooling potential and carbon credit earned for dome shaped house

M. Jamil Ahmad¹, G.N. Tiwari¹, Anil Kumar Singh², Manisha Sharma², H.N. Singh³

1 Center for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi-16, India.

2 Energy Research Applications, 211B, Pkt-C, Siddhartha Extension, New Delhi-14, India.

3 Department of Physics, R.S.S.P.G. College, Pilkhuwa, Ghaziabad, U.P. India.

Abstract: In this article, the heating/cooling potential of a dome shaped house has been evaluated on the basis of energy balance under quasi-steady state condition by incorporating the effect of ventilation/earth-air heat exchanger. The study has been carried out for composite climate of New Delhi. Effect of parameters of earth-air heat exchanger (radius of pipe, length of pipe and velocity of air) on heating/cooling potential has also been studied. Analysis of energy saving by using day lighting and CO₂ credit earned has also been carried out. It is observed that an over all 732 kWh energy can be saved per year by using day lighting which corresponds to 1.49 tones/year carbon credits earned.

10. Challenges for energy efficiency under programmatic CDM: case study of a CFL project in Chile

Charikleia Karakosta, Dimitris Askounis

National Technical University of Athens, School of Electrical and Computer Engineering, Management & Decision Support Systems Lab (NTUA-EPU), 9, Iroon Polytechniou str., 15780, Athens, Greece.

Abstract: Energy Efficiency (ENEF) is one of the most promising sectors for reducing emissions of sustained growth and increasing energy security in developing countries. ENEF is, however, severely underrepresented in the Clean Development Mechanism (CDM), due in large part to its dispersed nature, which cannot be easily accommodated into traditional CDM modalities. Furthermore, in the present context, uncertainty prevails to whether the CDM is actually procuring its aims in terms of achieving Sustainable Development (SD) as well as to what extent. On the other hand, programmatic CDM (pCDM) could become an important tool to both bundle small-scale projects and organise similar (not necessarily small-scale) projects carried out at different locations and scales. In this respect, pCDM could offer a promising framework to maximize SD benefits through the inclusion of ENEF activities in developing countries. Compact Fluorescent Lamps (CFLs) technology has a significant technical potential within Chile, but ‘somehow’ do not receive sufficient attention from relevant stakeholders and key market players. This paper presents an analysis that explores for Chile, the potential of CFLs to deliver key energy services for the country. In the above framework, a simulation will be presented on the potential of large-scale CFL deployment in Chile in CDM emissions trading, energy and environmental terms.

11. China's regional carbon emissions change over 1997-2007

Lan-Cui Liu¹, Jin-Nan Wang¹, Gang Wu^2,3, Yi-Ming Wei^2,3

1 Center for Climate and Environmental Policy, Chinese Academy of Environmental Planning, Ministry of Environmental Protection of the People’s Republic of China, Beijing 100012, China.

2 School of Management and Economics, Beijing Institute of Technology, Beijing, 100081, China.

3 Center for Energy and Environmental Policy Research, Beijing Institute of Technology, Beijing, 100081, China.

Abstract: The increased demand for energy in China has generated concomitant increase of carbon emissions, which poses an unprecedented challenge to China’s, and even global, sustainable development. In this paper, from the perspective of provincial carbon emissions, we analyze China’s carbon emissions changes during 1997-2007 based on the index decomposition analysis method. We find that: (1) China's CO₂ emissions from end-use energy consumption mainly originated from such major industrial provinces as Hebei, Jiangsu, Zhejiang, Shandong, Henan and Guangdong. (2) Economic growth and decline in energy intensity will have the greatest impact on CO₂ emissions from end-use energy consumption. Economic growth is the key factor driving the increase of CO₂ emissions. Change in energy intensity can more or less decrease CO₂ emissions. In the future, China’s carbon emissions mitigation policies should be developed to address these differences in provincial carbon emissions.

12. A comparative study of monthly mean daily clear sky radiation over India

A. K. Katiyar¹, Akhilesh Kumar¹, Chanchal Kumar Pandey¹, B.Das²

1 Department of Applied Sciences, Institute of Engineering and Technology, Lucknow-21, India.

2 Department of physics, Lucknow University, Lucknow-21, India.

Abstract: An attempt has been made to analyze the three years measured data of different Indian cities and to develop a new set of equations to estimate the monthly mean daily clear sky radiation over India. The statistical analysis has been used for present study. The comparison of present estimates has been made with various earlier proposed models. The root mean square error (RMSE) and mean bias error (MBE) have also been computed to test the accuracy of the proposed equations. The percentage of MBE with new constant for all stations under consideration is varying from 0.22 to 2.09 % while RMSE is varies from 2.22 to 10.37%. It is found that in comparison to other models, the results with new proposed equations estimates better for the climate of India.