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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 This paper aims to present a feasibility study of the innovative plant for methanol synthesis from carbon dioxide-sequestered by fossil fuel power plant and hydrogen, which is produced by water electrolyzer employing the over-production on the electrical grid. The thermo-economic analysis is performed in the framework of the MefCO2 H2020 EU project and it is referred to the German economic scenario, properly taking into account the real market costs and cost functions for different components of the plant. Three different plant capacities for methanol production (4000 10,000 and 50,000 ton/year) have been investigated, assuming an average cost for electrical energy to feed electrolysers and analyzing the influence of the most significant parameters (oxygen selling option, methanol selling price and electrolysers’ capital cost) on the profitability of the plant. The analysis has been performed in W-ECoMP, software for the thermo-economic analysis and plant optimization developed by the University of Genoa.

Abstract The present work attempts to devise an efficient method utilizing an on-grid photovoltaic-thermal heat pump water heater (PV-THPWH) integrated with a real-time variable frequency controller to achieve the goal of energy-efficient buildings. The prime focus is to reduce the grid's dependence on the compressor's energy-intensive operation by employing a feedback-controlled variable frequency drive (VFD). Additionally, the possibilities involved with addressing the electrical and thermal energy requirements of an energy-efficient building was investigated utilizing the proposed system. R-32 refrigerant in the photovoltaic-thermal (PV-T) evaporator coils of the heat pump assembly help to cool the photovoltaic (PV) panel while delivering the absorbed heat in the condenser to heat water contained inside the storage tank. Outdoor experiments and theoretical investigations of the combined system were carried out to appraise the dynamic behavior under varying solar irradiation and ambient temperature conditions. The observations conveyed that the PV-THPWH system succeeded in reducing the PV panel operating temperature by 25%, which resulted in a 20% increment in PV power output. Also, the performance indicators, such as the instantaneous energy efficiency and instantaneous PV efficiency, were found to increase by 15% and 34%, respectively, resulting in an average coefficient of performance of 6.4. For a clear sky day, the recorded total PV energy output was 4.67 units, while the VFD compressor consumption was 3.42 units, and the surplus 1.25 units were sent to the grid. Furthermore, the economic analysis reported a payback period of 2.3 years for the developed PV-THPWH system.

Large-size woody biomass is a valuable renewable resource to replace fossil fuels in biorefinery processes. The preprocessing of wood chips and briquettes is challenging to manage, especially in an industrial setting, as it generates a significant amount of dust and noise and occasionally causes unexpected accidents. As a result, a substantial amount of resources, energy, labor, and space are needed. The thermochemical conversion behavior of large-size woody biomass was studied to reduce energy consumption for chipping. Large-size wood was 1.5 m in length, 0.1 m in breadth, and stacked 90 cm in height. This strategy has many benefits, including increased effectiveness and reduced CO2 emissions. The target of this paper presents the thermochemical process, and large-size wood was chosen because it provides high-quality product gas while reducing the preprocessing fuel cost. This review examines the benefits of thermochemical conversion technologies for assessing the likelihood of carbon neutrality.

Energy conservation potential of the evaporative roof cooling technique for a cinema house in a composite climate (characterized by Delhi) has been evaluated. Thermal loads due to heat conduction through the building envelope, the required ventilation and the occupants have been taken into account. Life-cycle-cost analysis has been employed to evaluate the cost effectiveness of this energy conservation technique. It is seen that evaporative cooling on the roof leads to a net saving of 14% in the initial investment and 17% in the annual cost.

Investigating the impact of climate variables on net primary productivity is crucial to evaluate the ecosystem health and the status of forest type response to climate change. The objective of this paper is (1) to estimate spatio-temporal patterns of net primary productivity (NPP) during 2001 to 2010 in a tropical deciduous forest based on the input variable dataset (i.e.meteorological and biophysical) derived from the remote sensing and other sources and (2) to investigate the effects of climate variables on NPP during 2001 to 2010. The study was carried out in Katerniaghat Wildlife Sanctuary that forms a part of a tropical forest and is situated in Uttar Pradesh, India, along the Indo-Nepal border. Mean annual NPP was observed to be highest during 2007 with a value of 878 g C m-2 year-1 and 781.25 g C m-2 year-1 for sal and teak respectively. A decline in mean NPP during 2002-2003, 2005 and 2008-2010 could be attributed to drought, increased temperature and vapour pressure deficit (VPD). The time lag correlation analysis revealed precipitation as the major variables affecting NPP, whereas combination of temperature and VPD showed dominant effect on NPP as revealed by generalized linear modelling. The carbon gain in NPP in sal forest was observed to be marginal higher than that of teak plantation throughout the study period. The decrease in NPP was observed during 2010, pertaining to increased VPD. Contribution of different climatic variables through some link process was revealed in statistical analysis and clearly indicated the co-dominance of all the variables in explaining NPP.

Abstract The clathrate hydrate formation at the interface between liquefied carbon dioxide (CO 2 ) and liquid water is one of the key processes in the course of direct CO 2 disposal into deep seas—an option to mitigate the emission of CO 2 into the atmosphere. Eight different models have been proposed so far on the formation and metabolic self-preservation of a hydrate film at the interface and also the mass transfer of CO 2 across the hydrate film. This paper reviews those rival models one by one and illustrates how they are discrepant. Each model is critically examined, and if any, its weakness in physical reality or mathematical formulation is pointed out. The state of the art of hydrate-film modeling thus revealed suggests the necessity of more careful consulting of pertinent experimental observations to establish our physical view about hydrate films, which should serve as the base of any further work on hydrate-film modeling.

Abstract Due to gradually diminution of fossil fuel, the cost-effective utilization of available fuel for power generation has turn out to be a vital concern of electric power utilities. Thermal power plants have to operate within their fuel confines and contractual constraints. This work suggests social group entropy optimization (SGEO) technique to solve short-term generation scheduling of a power system consisting of fuel constrained thermal generating units, cascaded hydro power plants, solar PV plants, wind turbine generators and pumped storage hydro (PSH) plants with demand side management (DSM). Simulation results of the test system have been compared with those acquired by self-organizing hierarchical particle swarm optimizer with time-varying acceleration coefficients (HPSO-TVAC), fast convergence evolutionary programming (FCEP) and differential evolution (DE). Numerical results show that fuel consumption can be adequately controlled for fulfilling constraints imposed by suppliers and total cost with fuel constraints is more than the cost without fuel constraints. It has been also observed from the comparison that the suggested SGEO has the ability to bestow with superior-quality solution.

Abstract This paper attempts to measure consumers' perceived net benefits (or net costs) of energy-saving measures in using energy-consuming durable goods. Using the estimated net costs and the volume of CO2 reduced by the measures, a marginal abatement cost (MAC) curve for the average household's CO2 emissions is produced. An analysis using the curve suggests that in order to provide households with an incentive to take actions that can lead to CO2 emission reductions in using energy-consuming durables, a high level of carbon price is needed. In addition, a regression analysis reveals that the net benefits of the measures are larger for households that put a higher priority on energy saving, for those living in detached houses, for those with a smaller number of persons living together, and for those with less income. The result of the analysis using the MAC curve may suggest that promoting energy-saving behavior will require not only a policy to provide economic incentives but also interventions to influence psychological factors of household behavior.