Limits set by the Kyoto protocol brings Czech Republic billions of EUR from carbon emissions trading. The Ministry of Environment wants to invest the aforementioned revenue into energy savings and other projects like subsidies on the purchase of stoves for solid biofuels in regions with the most polluted air. Surprisingly, charcoal is not supported. Robust analysis of solid biofuels was made according to valid standards and routine chemical procedures. Data shows that there is no reason for charcoal to be rejected. It was confirmed that solid biofuels do not achieve the quality of black coal. The Czech Ministry of Environment argues that charcoal is not supported because of its high price per ton. The ecological criteria and price per energy should be also taken into account as analyzed in detail. Within the discussed ethical context, an improper form of support may affect market in a short term.
The present experimental work investigates the use of ethyne gas in biodiesel-fueled diesel engine at different flow rate of 1, 2, and 3 L/min and is compared with diesel operation. This work is aimed to examine the outcome of ethyne gas by dual-fuel operation on emission characteristics of neat biodiesel-fueled stationary diesel engine. The oil derived from mustard seeds are employed as a source for biodiesel. The work was carried out at 2100 rpm (speed) and at an optimal compression ratio of 17. Based on the outcome of this investigation, the maximum reduction in hydrocarbon (25.1%), carbon monoxide (17.24%), and smoke emission (24.8%) was observed for biodiesel-ethyne at 3 L/min than the neat biodiesel. However, NO x emissions were found to be 15.8% higher for ethyne-biodiesel fueling at 3 L/min owing to increase in combustion gas temperature than neat biodiesel.
This study details the effect of the Di-Methyl-Ether(DME) as a cetane improver on neat cashew nut shell biodiesel (CBD100) to assess the emission and performance engine characteristics. Four fuels, namely, diesel, biodiesel (Cashew nut shell Methyl Ester), a blend of CBD100-10% and 20% by volume of DME (CBD90DME10and CBD80DME20) are prepared and tested on a stationary research diesel engine. The experimental parameters for CBD80DME20 showed a 1.6% increase in thermal efficiency thereby reducing 4.1% of fuel consumption than the neat biodiesel at peak conditions. Experimental result exposed that 20% of DME reduces 3.4% CO, 4.2% HC and 8.8% NOx and 8.4% smoke emissions of CBD100. Based on the outcome of this work, it is clear that CBD80DME20 shall be employed as a substitute fuel for diesel engine. Abbreviations: CI: Compression ignition; CBD100: Cashew nut shell Bio-diesel; DME: Di-methyl ether; CO: Carbon monoxide; BTE: Brake thermal efficiency; BSFC: Brake specific fuel consumption; CBD100: 100% Biodiesel; CBD90DME10: 90% biodiesel + 10% di-methyl-ether; CBD80DME20: 80% biodiesel + 20% di-methyl-ether; HC: Hydrocarbon; NO x : Oxides of nitrogen.
In this present work, the investigations are carried out to study the performance, emission, and combustion characteristics of a single cylinder Compression Ignition (CI) engine using water-diesel emulsion fuel, and the alumina nanoparticles blended water-diesel emulsion fuels. The water-diesel emulsion fuel is prepared by the emulsification method in the proportion of 83% diesel, 15% water, and 2% surfactants by volume. The alumina nanoparticles are blended with the water-diesel emulsion fuel in the mass fractions of 25, 50, and 100 ppm systematically. The experiments are conducted at a constant speed of 1500 rpm and the results revealed a substantial enhancement in the performance and reduction in the harmful pollutants due to the incorporation of alumina nanoparticles in the water-diesel emulsion fuel. Furthermore, the hot-plate evaporation characteristics test asserted a considerable reduction in the evaporation time by adding the potential alumina nanoparticles to the water-diesel emulsion fuel.
Co-electrolysis of H 2 O and CO 2 was studied in solid oxide cells (SOCs) supported by nickel-/yittria-stabilized zirconia (Ni/YSZ) electrode. Polarization characterization indicates that electrochemical reduction of both CO 2 and H 2 O occurs during co-electrolysis. In parallel with the electrochemical reactions, the equilibrium of the water-gas shift reaction is reached, and moreover, CO is produced via the water-gas shift reaction. The degradation observed when performing co-electrolysis in these SOCs occurs mainly at the Ni/YSZ cathode and may be a consequence of impurities in the gas stream, adsorbing on active sites in the SOC. The low degradation is most likely acceptable for long-time operation.
The current experimental study is aimed to analyze the influence of single-walled Carbon Nano Tubes (CNT) on the emission characteristics of neem biodiesel-fueled (NBD-fueled) diesel engine and the results compared with conventional diesel. Experiments were conducted in a single-cylinder, 4-stroke, diesel engine with an eddy current dynamometer at a constant speed of 1500 rpm. Two samples of CNT are characterized and dispersed into 100% of the NBD in a mass fraction of 50 and 100 ppm using ultrasonicator, and the physicochemical properties were measured. Experimental results indicated that by adding CNT nanoparticles in NBD reduces its NO x , HC, CO, and smoke emission by 9.2%, 6.7%, 5.9%, and 7.8%, respectively, at all load conditions.
The application of solar drying technology in agricultural area to preserve vegetables, fruits, and other crops has proved to be practical, economical, and eco-friendly. In this communication, a comprehensive review of the various designs, details of construction, and operational principles of many practically realized designs of solar energy drying systems is presented. Solar drying system is used to dry crops extensively in many countries. It improves the quality of product, minimizes waste, and employs renewable energy sources. However, availability of suitable information is missing in many of the countries where solar drying systems are most needed. Such systems are available in varied range of sizes and designs and are used for drying various foods and agricultural products. At present, there are various types of dryers that are available to suit the needs of farmers, food, and grain distributors. Therefore, the selection of dryers for a particular situation is largely based on what is available and the types of dryers currently used are widely based on available circumstances. A synthesis view of classification of solar energy dryers is presented. Two groups of solar energy dryers can be identified, viz., passive or natural-circulation solar energy dryers and active or forced convection solar energy dryers. The appropriateness of each design type for application by farmers in developing countries is discussed. Some recent developments in solar drying technology are also discussed.
This work examines the effect of butanol (higher alcohol) on the emission pattern of neat neem oil biodiesel (NBD100) fueled diesel engine. Single-cylinder, 4-stroke, research diesel engine was employed to conduct the trial. Blends comprising the mixture of biodiesel and higher alcohol were prepared by employing an ultrasonic agitator. Four test fuels such as neat neem oil biodiesel, diesel, and two blends of higher alcohol/neem oil biodiesel: 10% and 20% (by volume). Experimental result showed that increasing alcohol content to biodiesel brought down the various emissions such as Smoke, NO x , HC, and CO by 6.8%, 10.4%, 8.6%, and 5.9%, respectively, at all loads. It was also concluded from the trail that a 20% higher alcohol/neem oil biodiesel blends show the promising signs in reducing all the emissions associated with biodiesel fuelled diesel engine.
Unlike the situation in the direct methanol fuel cell (DMFC) fed with dilute liquid methanol solution, the required water in anode for a DMFC fed with neat methanol is entirely transported from cathode. In this study, the water concentration in anode catalyst layer of such a DMFC operating with fully active mode is theoretically analyzed, followed by the experimental investigations on the effects of air flow rate and operating temperature on cell performance. The results revealed that the air flow rate has a strong impact on cell performance, especially at larger current density. Overmuch air causes rapid decline of cell performance, which results from the dehydration of membrane and lack of water in the anode reaction sites. Raising temperature induces faster reaction kinetics, while undesired stronger water dissipation from the DMFC. In practice, the stable cell resistance can be used as a criterion to help the DMFC to achieve a high and sustainable performance by finely combining the air flow rate and operating temperature.
According to the U.S. Department of Energy's wind energy scenario, 20% share of the U.S. energy portfolio is to come in from wind power plants by the year 2030. This research aims to quantify the direct and supply chain related indirect environmental impacts of onshore and offshore wind energy technologies in the United States. To accomplish this goal, a hybrid life cycle assessment (LCA) model is developed. On average, offshore wind turbines produce 48% less greenhouse gas emissions per kWh produced electricity than onshore wind turbines. It is also found that the more the capacity of the wind turbine, the less the environmental impact when the turbine generates per kWh electricity.
The use of a latent heat storage system using Phase Change Materials (PCM) is an effective way of storing thermal energy (solar energy, off-peak electricity, industrial waste heat) and has the advantages of high storage density and the isothermal nature of the storage process. It has been demonstrated that, for the development of a latent heat storage system, choice of the PCM plays an important role in addition to heat transfer mechanism. The information on the latent heat storage materials and systems is enormous and published widely in the literatures. In this paper, we make an effort to gather the information from the previous works on PCMs and latent heat storage systems. This review will help to find a suitable PCM for various purposes a suitable heat exchanger with ways to enhance the heat transfer, and it will also help to provide a variety of designs to store the heat using PCMs for different applications, i.e. space heating & cooling, solar cooking, greenhouses, solar water heating and waste heat recovery systems. Measurement techniques of thermophysical properties, studies on thermal cycles for long term stability, corrosion of the PCMs and enhancement of heat transfer in PCM are discussed. New PCM innovations are also included for the awareness of new applications. This paper contains a list of about 250 PCMs and more than 250 references.
Citrus peel waste is a valuable lignocellulosic feedstock for bioethanol production due to its richness in fermentable sugars and low lignin content. Citrus peel contains two major value-added products: d-limonene and pectin. d-Limonene is widely used in food, cosmetics, and pharmaceutical industries. However, it acts as a microbial growth inhibitor for yeast during the fermentation process and hence it has to be removed prior to fermentation. Pectin is used as thickening agent, gelling agent, and stabilizer in the food industry. Since pectin increases the viscosity of the fermentation medium and makes fermentation troublesome, it has to be either extracted or degraded into galacturonic acid using pectinase enzyme. Thus, the removal and recovery of both D-limonene and pectin from citrus peel are essential for better fermentation. For bioethanol production, pretreatment plays a crucial role in the utilization of citrus peels since the reduction of d-limonene concentration to less than 0.05% is necessary. This review solely describes the potential of citrus waste for value added products such as d-limonene and pectin and the production of bioethanol from citrus peel waste is discussed in detail.
After energy, water is the most critical commodity to be made available to people to keep them alive. Saudi Arabia has vast land and people are living in all regions. Most of these are connected to national grid but some are not, especially in remote areas like in the north, south, and west south. Pumping water in remote areas for domestic needs like agriculture and animals beside human needs is essential and require regular power supply. The present idea of wind-PV-Battery hybrid power system based on 100% renewable source is being proposed to utilize and tested in some of the regions on experimental bases. Of the five locations chosen for the purpose, namely Dhahran, Riyadh, Jeddah, Guriat and Nejran, some are good from both wind and solar intensity point of view some have good winds only and some good solar only. Nearly optimal size of PV-Wind water pumping system is determined for each of these sites considering the availability of solar and wind energy distributions throughout the year in these sites. It is shown that the monthly total water pumping capacity when using nearly optimal PV-Wind water pumping system is fairly uniform throughout the year except for the sites of Guriat and Riyadh. In these sites higher water pumping capacity is observed during the spring and summer months. On the other hand the cost of underground water pumping is found to vary between 6 to 12 US¢/m 3 for the five sites considered.
The large scatter in the predictions of wave energy costs, which is caused in part by the simplifications assumed by existing models, is a hindrance for the development of this promising renewable. In this context, the main objective of this paper is to reassess the cost of wave energy taking into account a number of elements that are usually overlooked, or not considered simultaneously. This analysis has been performed in relation to the European context. The direct and indirect costs of a wave farm are examined, and a value for each is presented. The levelized cost (€/MWh) of wave energy is then calculated for different scenarios in order to compare the profitability of wave energy with that of other energy sources. After that, a sensitivity analysis is carried out to identify the main parameters affecting the total cost, considering in particular the effect on the levelized cost of considering: (i) the cost reductions arising from economies of scale and technological effects; (ii) an O&M cost variable throughout the useful life of the farm; and (iii) the externalities. In sum, this work sets the basis for a thorough economic comparison of wave energy with other sources of energy.
The objective of the present work is to evaluate the opportunity of the wind farms implementation in the north-western side of the Black Sea. An assessment of the wind energy potential was first carried out by analyzing eleven years of data. Both in situ measurements and model data coming from the European Centre for Medium-Range Weather Forecasts were considered at this level. Using a classical logarithmic transformation law, the wind speeds were translated to the height of 80 m where usually the wind turbines operate. The analysis of the in situ measurements indicates the Romanian coastal environment as being more energetic during the winter season, with an average wind speed at 80 m of about 9.7 m/s and a power density of 870W/m 2 . On the other hand, the analysis of the model dataset indicates that the Ukrainian nearshore is slightly more energetic during the winter season with an average wind speed of 7.5 m/s and a power density of 310W/m 2 . As a further step, the seasonal and spatial distributions of the wind energy were evaluated in terms of the power estimated to be delivered by the Siemens 2.3 wind turbine. Finally, the regional wind energy resources are compared with similar ones from locations in which offshore wind farms are known to operate or are expected to be developed in the near future. The main conclusion coming from the present work would be that the north-western side of the Black Sea represents a promising area for the wind energy extraction.
This paper focuses on the exergetic sustainability indicators of a medium-range commercial aircraft engine for constant reference environment and ground running conditions. First, a detailed exergy analysis of turbofan engine have been performed based on engine test cell parameters. Starting from the sustainability considerations and the second law of the thermodynamics, the paper presents six exergy-based sustainability indicators. The indicators of the turbofan engine developed here in conjunction with exergetic analysis and sustainable development are exergy efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy rate, environmental effect factor, and exergetic sustainability index. The investigated sustainable indicators have been calculated by using exergy analysis outputs for aircraft ground running condition. Results from this study show that values of exergy efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy rate, environmental effect factor, and exergetic sustainability index of investigated turbofan engine are found to be 0.315, 0.685, 0.408, 0, 2.174, and 0.460, respectively. These parameters are expected to quantify how the turbofan engine and aircraft become more environmentally benign and sustainable.
The review deals with fuel ethanol production from plant-based lignocellulosic biomass as raw materials. In this article, the technologies for producing fuel ethanol with the main research prospects for improving them are discussed. The complexity in the biomass processing is identified by the analysis of various stages involved in the conversion of lignocellulosic biomass into fermentable sugars. Further, the fermentation processes with its important features are explained based on biomass conversion. Comparative index for different types of biomass for fuel ethanol production is listed. Finally, some concluding remarks on current research regarding the pre-treatment along with biological conversion of biomass into ethanol are presented.
Pyrolysis of polypropylene (PP) and high density polyethylene (HDPE) into fuel like products was investigated over temperature range of 250- 400°C. The product yields as a function of temperature were studied. Total conversion as high as 98.66% (liquid; 69.82%, gas; 28.84%, and residue; 1.34%) was achieved at 300°C in case of PP and 98.12% (liquid; 80.88%, gas; 17.24%, and residue; 1.88%) in case of HDPE at 350°C. The liquid fractions were analyzed by FTIR and GC-MS. The results showed that the liquid fractions consisted of a wide range of hydrocarbons mainly distributed within the C 6 -C 16 . The liquid product obtained in case of PP is enriched in the naphtha range hydrocarbons. Similarly, the liquid product obtained in case of HDPE is also enriched in naphtha range hydrocarbons with preponderance in gasoline and diesel range hydrocarbons. The% distribution of paraffinic, olefinic, and naphthenic hydrocarbons in liquid product derived from PP is 66.55, 25.7, and 7.58%, respectively, whereas in case HDPE, the% distribution is 59.70, 31.90, and 8.40%, respectively. Upon comparing the hydrocarbon group type yields, PP gave high yield of paraffinic hydrocarbons while HDPE gave high yields of olefins and naphthenes. The whole liquid fractions and their corresponding distillates fractions were also analyzed for fuel properties. The results indicated that the derived liquid fractions were fuel-like meeting the fuel grade criteria.
First and second law approaches have been used to analyze the performance of a humidified Brayton/Brayton power cycle. The energy efficiency and exergy destruction rates consistently improved when the combustion temperature was increased. Both performance indicators improved, reached an optimum, and then deteriorated when the topping cycle pressure ratio increased, while their sensitivity to the bottoming cycle pressure ratio depended on the humidification rate used at the bottoming cycle. Upon increasing the mass flowrate of air through the bottoming cycle, the energy efficiency of the power cycle increased linearly, while the irreversibility generation had a non-monotonic variation. In all cases, a higher degree of humidification always resulted in greater first and second law performances.
Thermal potential for cooling and heating can be achieved by new configuration of earth-air heat exchanger (EAHE). This paper presents a numerical investigation of thermal performance of a spiral-shaped configuration of EAHE intended for the summer cooling in hot and arid regions of Algeria. A commercial finite volume software (ANSYS FLUENT) has been used to carry out the transient three-dimensional simulations and the obtained results have been validated using the experimental and numerical data obtained from the literature. The agreement between our simulation results and those from literature is very satisfactory. A parametric analysis of the new geometry of (EAHE) has been performed to investigate the effect of pitch, depth, pipe length and of the flow velocity on the outlet air temperature and the EAHE's mean efficiency as well as its coefficient of performance (COP). It has been shown that when the pitch space varies between 0.2 and 2 m the difference of outlet air temperature increases by 6 ° C. When the air velocity increases from 2 to 5 m/s the mean efficiency decreases from 60 % to 33 % and the COP of the EAHE decreases from 2.84 to 0.46.