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Abstract In this work addition of ethanol to high viscosity jatropha methyl ester (JME) through port injection is investigated in order to determine its effect fuel viscosity reduction on diesel engine performance. In addition to viscosity alteration, the impact of ethanol addition on combustion characteristics such as combustion duration, ignition delay and emissions levels from diesel engines fuelled with blends of ethanol, diesel and JME is studied in particular. It is found that blending of oxygenated fuels with diesel modifies the chemical structure and physical properties which again alter the engine operating conditions, combustion parameters and emissions levels. However, the injection of only 5% ethanol through port injection allows for a total of 25% blending of biofuels into diesel yet keeping the fuel characteristics close to that of conventional diesel. However, both experimental and numerical results show that ethanol addition in JME blended diesel results in a slight increase in fuel consumption and thermal efficiency for the same power outputs as that of conventional diesel fuel. Also, the combustion characteristics with ethanol addition include improved maximum in-cylinder peak pressure, cumulative heat release (CHR) rate of heat release (ROHR), in-cylinder peak temperature and combustion duration. Regarding emission characteristics the experimental results show significant reduction in smoke, carbon monoxide (CO) and total hydrocarbon (THC) emissions with extended oxygen mass percentage in the fuel at higher engine loads. However, oxides of nitrogen (NOx) emissions are found to increase at high loads although the common tradeoff between smoke and NOx is found to be more prominent for the oxygenated fuels.

Abstract In this work addition of ethanol to high viscosity jatropha methyl ester (JME) through port injection is investigated in order to determine its effect fuel viscosity reduction on diesel engine performance. In addition to viscosity alteration, the impact of ethanol addition on combustion characteristics such as combustion duration, ignition delay and emissions levels from diesel engines fuelled with blends of ethanol, diesel and JME is studied in particular. It is found that blending of oxygenated fuels with diesel modifies the chemical structure and physical properties which again alter the engine operating conditions, combustion parameters and emissions levels. However, the injection of only 5% ethanol through port injection allows for a total of 25% blending of biofuels into diesel yet keeping the fuel characteristics close to that of conventional diesel. However, both experimental and numerical results show that ethanol addition in JME blended diesel results in a slight increase in fuel consumption and thermal efficiency for the same power outputs as that of conventional diesel fuel. Also, the combustion characteristics with ethanol addition include improved maximum in-cylinder peak pressure, cumulative heat release (CHR) rate of heat release (ROHR), in-cylinder peak temperature and combustion duration. Regarding emission characteristics the experimental results show significant reduction in smoke, carbon monoxide (CO) and total hydrocarbon (THC) emissions with extended oxygen mass percentage in the fuel at higher engine loads. However, oxides of nitrogen (NOx) emissions are found to increase at high loads although the common tradeoff between smoke and NOx is found to be more prominent for the oxygenated fuels.

Abstract Many countries committed themselves in the Kyoto protocol to reduce greenhouse gas (GHG) emissions. Some of these targeted emission reductions could result from a switch from coal-fired to gas-fired electricity generation. The focus in this work lies on Western Europe, with the presence of the European Union Emission Trading Scheme (EU ETS). For the switching to occur, several conditions have to be fulfilled. First, an economical incentive must be present, i.e. a sufficiently high European Union Allowance (EUA) price together with a sufficiently low natural gas price. Second, the physical potential for switching must exist, i.e. at a given load, there must remain enough power plants not running to make switching possible. This paper investigates what possibilities exist for switching coal-fired plants for gas-fired plants, dependent on the load level (the latter condition above). A fixed allowance cost and a variable natural gas price are assumed. The method to address GHG emission reduction potentials is first illustrated in a methodological case. Next, the GHG emission reduction potentials are addressed for several Western European countries together with a relative positioning of their electricity generation. GHG emission reduction potentials are also compared with simulation results. GHG emission reduction potentials tend to be significant. The Netherlands have a very widespread switching zone, so GHG emission reduction is practically independent of electricity generation. Other counties, like Germany, Spain and Italy could reduce GHG emissions significantly by switching. With an allowance cost following the switch level of a 50% efficient gas-fired plant and a 40% efficient coal-fired plant in the summer season (like in 2005), the global GHG emission reduction (in the electricity generating sector) for the eight modeled zones could amount to 19%.

Abstract Many countries committed themselves in the Kyoto protocol to reduce greenhouse gas (GHG) emissions. Some of these targeted emission reductions could result from a switch from coal-fired to gas-fired electricity generation. The focus in this work lies on Western Europe, with the presence of the European Union Emission Trading Scheme (EU ETS). For the switching to occur, several conditions have to be fulfilled. First, an economical incentive must be present, i.e. a sufficiently high European Union Allowance (EUA) price together with a sufficiently low natural gas price. Second, the physical potential for switching must exist, i.e. at a given load, there must remain enough power plants not running to make switching possible. This paper investigates what possibilities exist for switching coal-fired plants for gas-fired plants, dependent on the load level (the latter condition above). A fixed allowance cost and a variable natural gas price are assumed. The method to address GHG emission reduction potentials is first illustrated in a methodological case. Next, the GHG emission reduction potentials are addressed for several Western European countries together with a relative positioning of their electricity generation. GHG emission reduction potentials are also compared with simulation results. GHG emission reduction potentials tend to be significant. The Netherlands have a very widespread switching zone, so GHG emission reduction is practically independent of electricity generation. Other counties, like Germany, Spain and Italy could reduce GHG emissions significantly by switching. With an allowance cost following the switch level of a 50% efficient gas-fired plant and a 40% efficient coal-fired plant in the summer season (like in 2005), the global GHG emission reduction (in the electricity generating sector) for the eight modeled zones could amount to 19%.

Abstract This present investigation focuses on combustion-performance-emission characteristics of cerium oxide (CeO2) added palm biodiesel blends in a single cylinder diesel engine. Experiments are conducted in a natural aspirated single cylinder diesel engine at constant speed and varying load (low, medium and full). The experimental result reveals that the addition of CeO2 nanoparticles (50, 100, and 150 ppm) to palm biodiesel blends enhanced brake thermal efficiency (BTE) with reduction in brake specific energy consumption (BSEC) due to improved ignition characteristics of the modified blends. Maximum reduction of CO, HC and NOx emissions have been observed 50, 48.45, and 11.1% at full load respectively. Later on, friction and wear study has been conducted to investigate tribological behavior of cylinder liner-piston materials under lubrication (using contaminated lubricant). The whole friction and wear study has been performed on pin-on-disc tribometer at different speed (300, 400, and 500 rpm) and load (10, 30, and 50 N). The dilution of CeO2 added biodiesel blends with the lubricant resulted low coefficient of friction (COF) and specific wear rate. At varying speed of 300, 400, and 500 rpm: 6.07, 8.5, and 10.9%; and at varying load of 10, 30, and 50 N: 6.07, 10.96, and 11.77% lower average COF have been observed respectively for nanofuels contaminated lubricant compared to diesel contaminated lubricant. Similarly, 7.94, 30, & 28.06% and 7.94, 30.33, & 17.04% lower specific wear rate at varying speed and load have been observed respectively for nanofuels contaminated lubricant.

Abstract This present investigation focuses on combustion-performance-emission characteristics of cerium oxide (CeO2) added palm biodiesel blends in a single cylinder diesel engine. Experiments are conducted in a natural aspirated single cylinder diesel engine at constant speed and varying load (low, medium and full). The experimental result reveals that the addition of CeO2 nanoparticles (50, 100, and 150 ppm) to palm biodiesel blends enhanced brake thermal efficiency (BTE) with reduction in brake specific energy consumption (BSEC) due to improved ignition characteristics of the modified blends. Maximum reduction of CO, HC and NOx emissions have been observed 50, 48.45, and 11.1% at full load respectively. Later on, friction and wear study has been conducted to investigate tribological behavior of cylinder liner-piston materials under lubrication (using contaminated lubricant). The whole friction and wear study has been performed on pin-on-disc tribometer at different speed (300, 400, and 500 rpm) and load (10, 30, and 50 N). The dilution of CeO2 added biodiesel blends with the lubricant resulted low coefficient of friction (COF) and specific wear rate. At varying speed of 300, 400, and 500 rpm: 6.07, 8.5, and 10.9%; and at varying load of 10, 30, and 50 N: 6.07, 10.96, and 11.77% lower average COF have been observed respectively for nanofuels contaminated lubricant compared to diesel contaminated lubricant. Similarly, 7.94, 30, & 28.06% and 7.94, 30.33, & 17.04% lower specific wear rate at varying speed and load have been observed respectively for nanofuels contaminated lubricant.

Abstract Combined absorption cooling device and humidification-dehumidification desalination component is newly proposed to be an alternative system to substitute the existing individual conventional arrangement for the betterment of energy usage. Specifically, among many waste heat recovery technologies, the combination of cooling and humidification-dehumidification processes is an innovative thought to implement a new thermodynamic system for improving the overall system performance. To be successful implementation of this innovation concept, in this study, both the above systems are combined to produce simultaneously 150 kW cooling effect and 0.1 kg s−1 freshwater production. This combined system also improves the effective use of waste heat. A parametric study of the proposed system is carried out to determine the optimum operational effect by varying different design constants based on the energy, exergy, and economic analyses. A multi-objective optimization model is also developed using the non-dominated storing genetic algorithm (NSGA-II) to obtain the minimum operating cost. In the optimization study, the total exergy efficiency is considered to be a maximization function and the total product cost is treated as a minimization objective. The results obtained from the exergy and economic studies reveal that the cooling assembly is the primary source for the irreversibility production with the exergy destruction rate of 17.0415 kW. Also, the exergoeconomic factor of humidifier is the lowest one (0.94%). From the multi-objective optimization, the total exergy efficiency and the total product cost are calculated as 0.5014 and 68.1680 $ GJ−1, respectively. At the optimum operating condition, calculated values of the gained output ratio (GOR) and coefficient of performance (COP) are 2.0181 and 1.2474, respectively. Furthermore, the present combined system is compared with the traditional humidification-dehumidification desalination system. This comparison highlights that the GOR of the proposed system is about 140% higher than the traditional system. Therefore, there is no doubt to be arising in mind that the operation of the proposed system produces more beneficial thermal aspects in comparison to the existing system.

Abstract Combined absorption cooling device and humidification-dehumidification desalination component is newly proposed to be an alternative system to substitute the existing individual conventional arrangement for the betterment of energy usage. Specifically, among many waste heat recovery technologies, the combination of cooling and humidification-dehumidification processes is an innovative thought to implement a new thermodynamic system for improving the overall system performance. To be successful implementation of this innovation concept, in this study, both the above systems are combined to produce simultaneously 150 kW cooling effect and 0.1 kg s−1 freshwater production. This combined system also improves the effective use of waste heat. A parametric study of the proposed system is carried out to determine the optimum operational effect by varying different design constants based on the energy, exergy, and economic analyses. A multi-objective optimization model is also developed using the non-dominated storing genetic algorithm (NSGA-II) to obtain the minimum operating cost. In the optimization study, the total exergy efficiency is considered to be a maximization function and the total product cost is treated as a minimization objective. The results obtained from the exergy and economic studies reveal that the cooling assembly is the primary source for the irreversibility production with the exergy destruction rate of 17.0415 kW. Also, the exergoeconomic factor of humidifier is the lowest one (0.94%). From the multi-objective optimization, the total exergy efficiency and the total product cost are calculated as 0.5014 and 68.1680 $ GJ−1, respectively. At the optimum operating condition, calculated values of the gained output ratio (GOR) and coefficient of performance (COP) are 2.0181 and 1.2474, respectively. Furthermore, the present combined system is compared with the traditional humidification-dehumidification desalination system. This comparison highlights that the GOR of the proposed system is about 140% higher than the traditional system. Therefore, there is no doubt to be arising in mind that the operation of the proposed system produces more beneficial thermal aspects in comparison to the existing system.

Building integrated photovoltaics (BIPV) coupled with phase change materials (PCM) (BIPV/PCM) provide opportunities for reducing the photovoltaic (PV) panel temperature to increase the overall efficiency of the BIPV, while also transferring the extracted heat for building energy load management. A comprehensive numerical study is conducted to simulate the effects of different BIPV design parameters namely, BIPV height (H), air gap between BIPV/PCM and wall (δ Air), PCM thickness (δ PCM), and air mass flow rate (ṁ) on the maximum PV panel temperature, the power production by the PV, and the energy extracted by the air. Optimum BIPV/PCM designs are derived from the studies for three different phase change materials, with the goal of maximizing the total energy from photovoltaics (E PV) and extracted heat (E air), subject to the constraint of keeping the maximum PV panel temperature to within acceptable values. From the obtained results it is concluded that for the selected range of parameters, the optimum values of δ PCM, H, δ Air and ṁ are, respectively, 0.04 m, 3 m, 0.02 m and 0.18 kg/s for maximizing E PV and 0 m, 3 m, 0.08 m and 0.091 kg/s for maximizing E air without any constraints.