Low Thermal Efficiency Research Articles

Prediction of the influence of castor oil–ethanol–diesel​ blends on single-cylinder diesel engine characteristics using generalized regression neural networks (GRNNs)

With some inferior fuel properties such as cetane number, flash point and calorific value, in this study the ethanol–diesel blend was improved through the use of neat castor oil. According to a preliminary study on blending stability and lubricity, a fuel blend was formulated with 10% ethanol, 10% castor oil and 80% diesel fuel (D80E10C10) which was selected to test in the diesel engine. The generalized regression neural network (GRNNs), which is one of the artificial intelligence algorithms that is suitable for a small data set, was applied to create a model for predicting the influence of castor oil on the characteristics of the diesel engine fueled with an ethanol–diesel blend. The experimental results of fuel properties were firstly analyzed and revealed that the presence of 10% castor oil can improve the defective fuel properties of ethanol–diesel to keep them under the limitations of the diesel fuel specification. A lower thermal efficiency was obtained with the combustion of the castor oil blend. A higher peak of in-cylinder pressure and the earlier start of combustion was achieved with increasing engine operating load and compression ratio. A lower peak of heat release rate was attained with the combustion of the castor oil blend. Hydrocarbons and carbon monoxide were increased with the castor oil blend, while oxides of nitrogen were decreased and no significant change in smoke emissions was found with respect to diesel fuel. Subsequently, the results of the prediction model concluded that the response surface methodology was a good method to optimize the smoothing parameter of the GRNNs model in the case of multi-output factors with different levels of importance. The GRNNs model was achieved with relatively high performance to predict BSFC, thermal efficiency, NOx, HC, CO and smoke emissions, with mean absolute percentage error (MAPE) values in the range of 1.562%–8.181% and coefficient of determination (R2) in the range of 0.708-0.993.

Numerical modelling of a direct current non‐transferred thermal plasma torch for optimal performance

AbstractA laminar steady‐state 2D axisymmetric model of a direct current (DC) thermal plasma torch using a magneto‐hydrodynamic approach has been developed. The model takes into account the entire torch system comprising the plasma gas injection, the inner region of the torch, and the jet exiting into the ambient environment. Numerical results are obtained for two different power inputs chosen from published experimental data. The temperature predictions at the torch exit are found in good agreement with experimental results. Velocity analysis of the plasma jet has been presented and the impact of electromagnetic force on jet velocity is analysed. The Lorentz force arising due to the coupling of fluid motion and electromagnetic forces shoots up the jet velocity to significantly high values near the cathode tip. Temperature and velocity profiles are in good agreement with the characteristics of a long laminar plasma jet. An operating value of heat transfer coefficient (h) has been suggested for optimal torch operation, thus ensuring a low anode erosion rate and acceptable thermal efficiency. The argon torch has the maximum temperature and longest jet length among the plasma gases considered.

Transient analysis of cryogenic cooling performance for high-power semiconductor lasers using flash-evaporation spray

• Transient phase-change heat transfer analysis was performed in cryogenic regimes. • A heat flux estimation method that considers an imposed heat flux was proposed. • The moderate spurt duration (Δ t = 30 s) produced preferable cooling performance. • Small-orifice-diameter nozzle has low cooling rate but high thermal efficiency. Focusing on the cryogenic cooling for the high-power semiconductor lasers to improve their output performance, this work conducted an experimental investigation on analyzing the transient cooling performance using a single-pulsed flash-evaporation spray with the environmental cryogen R32. A heat flux calculation methodology that considers an imposed heat flux as a boundary condition, was first developed to assist the transient heat transfer analysis. The results provided further insight into phase-change heat transfer on the hot surface from high-temperature to cryogenic regimes through coupling the heat transfer measurements with observations of hydrodynamic liquid film formation and development. The moderate spurt duration (Δ t = 30 s) that produced a large temperature drop (109.5 °C) and high time-averaged cooling rate (24.1 W/cm 2 ) was preferable. The significant losses in droplets’ momentum and mass contributed to the fast decrease in cooling effect as nozzle-to-surface distance ( Z ) increased. Specifically, shortening Z from 50 to 10 mm not only increased the maximum surface heat flux from 19.6 to 73.6 W/cm 2 , but also broadened the temperature region with high heat flux. The nozzle with a smaller orifice diameter (0.5 mm) produced a lower cooling rate. Whereas surprisingly, its lower flow rate resulted in the lesser coolant accumulation and splashing on the hot surface, which elevated its thermal efficiency. The low spray thermal efficiencies (≤16.2%) in the present work attribute to the low liquid utilization and coverage area across the hot spot surface under the spray impact.

Effect of microstructure of nanoparticles and surrounding alcohol groups on energy transfer efficiency

• The higher water content, the greater the thermal conductivity of alcohol solutions. • Thermal conductivity of alcohol nanofluids is obviously higher than the base fluids. • There is a non-escaping adsorption layer on the surface of the Cu nanoparticles. • Presence of nanoparticles results in the microstructure change of the system. • The solid-like microstructure results in an increase of thermal conductivity. The low solar thermal conversion efficiency is an obstacle to the development of a new generation of high-efficiency energy-saving technologies. An important measure to improve the conversion efficiency is to improve the thermal conductivity of the working fluid. Nanofluids have a higher thermal conductivity than conventional fluids, which provides a strategy idea toward solving this problem. In this paper, three kinds of traditional fluids, ethanol, ethylene glycol (EG) and 1,2-propylene glycol (PG), were used as base solutions, and Cu nanoparticles with different volume fractions were added to form their corresponding nanofluids. The thermal conductivity of the different alcohol solutions and their nanofluid systems were simulated using molecular dynamics and the thermal conductivity enhancement mechanisms of these nanofluids on a micro-level were simulated and analyzed. It was found that the thermal conductivity of the ethanol/EG/PG-water solution was positively correlated with the water content of the system. The addition of Cu nanoparticles improved the thermal conductivity of the three kinds of alcohol nanofluids. The existence of base solution molecular adsorption layer on the surface of nanoparticles was an important factor contributing to the improvement of the thermal conductivity of nanofluids. Through the radial distribution function of the nanofluid system, and the visualization of the molecules in the adsorption layer, it was found that the arrangement of base solution molecules in the adsorption layer was similar to the orderly arrangement of solids. This type of solid-like microstructure rendered better heat transfer performance of the nanofluid than the base solution. Within the scope of this study, the maximum increase in the rate of the thermal conductivity of the ethanol/EG/PG-water solutions was 14.2, 30.6 and 22.6 %, respectively. In the alcohol nanofluid system, the thickness of the adsorption layer on the surface of Cu nanoparticles was ∼0.45 nm, which increased or decreased slightly based on the type of base solution. The above findings provide an important reference for improving solar thermal conversion efficiency.

Thermal efficiency improvement and emission reduction potential by adopting improved biomass cookstoves for sauce-cooking process in rural Ethiopia

Sauce (“Wot”) preparation and Injera baking using an open-fire stove are recurrent cooking activities in rural households in Ethiopia. The low thermal efficiency open-fire stove utilized huge quantities of fuel and caused high particulate matter exposure for cookers. A rocket stove is proposed and fabricated that burns commonly used biomass fuel. The Aprovecho Research Center design guiding principles were followed to develop the prototype. The overall performance of the model was tested using a water boiling test (WBT version 4.2.3) to confirm thermal efficiency improvement and air pollutant reduction compared to the conventional stove. Indoor air pollution (IAP) measuring apparatus was installed to record the carbon monoxide (CO) and fine particulate matter (PM 2.5 ) emission exposure of the cooker during the WBT test. The performance testing result of the model has shown an improved thermal efficiency of 32% compared to the three-stone stove (14%). The stove reduced CO concentration by 42% and PM 2.5 concentration by 99.5% over the three-stone stove. The average concentration exposure for an hour (3.1 μg/m 3 CO) of the new stove satisfies the World Health Organization indoor air quality standard. Furthermore, the stove showed a 43% reduction in specific fuel consumption (roughly 625 kg fuel saving/year/device). The fuel-saving achieved from the model resulted in the reduction of CO 2 gas emissions by 1.3 tCO 2 /year. Therefore, it is assumed that the rocket stove has a considerable improvement over the open-fire stove and its timely development may enhance environmental care. Therefore, shifting the cooking technology from the conventional traditional cooking stove to rocket stoves could mitigate indoor air pollutant emissions and deforestation. • A rocket stove was fabricated and tested in a water boiling test. • The average thermal efficiency of the stove was found to be 32%. • The stove reduced CO concentration by 42% over the three-stone stove. • The stove reduced specific fuel consumption by 43% as compared to open fire stove. • The CO 2 emission saving of the stove was found to be 1.3 tCO 2 /year.

Superelastic, Highly Conductive, Superhydrophobic, and Powerful Electromagnetic Shielding Hybrid Aerogels Built from Orthogonal Graphene and Boron Nitride Nanoribbons.

Three-dimensional (3D) elastic aerogels enable diverse applications but are usually restricted by their low thermal and electrical transfer efficiency. Here, we demonstrate a strategy for fabricating the highly thermally and electrically conductive aerogels using hybrid carbon/ceramic structural units made of hexagonal boron nitride nanoribbons (BNNRs) with in situ-grown orthogonally structured graphene (OSG). High-aspect-ratio BNNRs are first interconnected into a 3D elastic and thermally conductive skeleton, in which the horizontal graphene layers of OSG provide additional hyperchannels for electron and phonon conduction, and the vertical graphene sheets of OSG greatly improve surface roughness and charge polarization ability of the entire skeleton. The resulting OSG/BNNR hybrid aerogel exhibits very high thermal and electrical conductivity (up to 7.84 W m-1 K-1 and 340 S m-1, respectively) at a low density of 45.8 mg cm-3, which should prove to be vastly advantageous as compared to the reported carbonic and/or ceramic aerogels. Moreover, the hybrid aerogel possesses integrated properties of wide temperature-invariant superelasticity (from -196 to 600 °C), low-voltage-driven Joule heating (up to 42-134 °C at 1-4 V), strong hydrophobicity (contact angel of up to 156.1°), and powerful broadband electromagnetic interference (EMI) shielding effectiveness (reaching 70.9 dB at 2 mm thickness), all of which can maintain very well under repeated mechanical deformations and long-term immersion in strong acid or alkali solution. Using these extraordinary comprehensive properties, we prove the great potential of OSG/BNNR hybrid aerogel in wearable electronics for regulating body temperature, proofing water and pollution, removing ice, and protecting human health against EMI.

Analysis of Gas Turbine Power Plant Production and Fuel Consumption

The main problem of gas turbine generating units operating in the simple cycle system is their relatively low thermal efficiency, which leads to large thermal energy losses. The current research aims to study the economic analysis of Kirkuk gas power plant. Field data of gas turbine unit for the year of 2019 were used. The results of the study showed that the cost of exported energy is higher than the cost of energy produced. The results showed a 23% increase in the cost of energy produced in summer compared to winter. A decrease in actual production compared to the planned production is observed by 12.8%, where the highest actual production for the month of March was 162,108 MW, while the planned was 186,000 MW. Also, the month of July witnessed a very low fuel consumption rate for natural gas compared to the rest of the months, where the average fuel consumption was 0.273 m3/kW, while the month of January has a high fuel consumption rate for natural gas compared to the rest of the year with average fuel consumption of 0.312 m3/kW. The rate of increase in fuel consumption between July and January was 14.2%, and the results also showed that the ratio of production to design capacity for January was the highest and amounted to 87%, and the highest efficiency reached 33%, while July was the lowest production rate in terms of design capacity, reaching 53% and efficiency of 29.8%.

Experimental investigation on the thermal appraisal of heat pipe-evacuated tube collector-based water heating system integrated with PCM

There is a great deal of research being done on the performance of solar collectors. Evacuated tube solar collectors are a mature technology that has proved reassuring performance for heat generation. However, low thermal efficiency remains their main challenge. Therefore, research to improve the efficiency of Evacuated Tube of Solar has continued to date based on some new approaches. The present study presented various designs of Evacuated Tube of Solar collector (ETSC) thermally enhanced by the addition of reflectors and thermal storage units with phase change materials and nanoparticles. The proposed models were assessed during different periods and different zones in Tunisia, especially in the Northern and Southern regions. This work established the energy balance of solar thermal systems determined by the input/output method. Assumptions and mathematical relations are presented for the proposed designs. Additionally, measured and regression useful energy as a function of the daily cumulative global solar energy of all ETSC-types was also evaluated. Research gaps in this field are identified and future research trends and directions are recommended.

Ultra-high power laser for vitrification of borosilicate glass

The glass solidification technology has been studied by many researchers for decades to handle the trouble of high-level liquid waste (HLLW). However, the widely used joule-heated ceramic melter technology also has disadvantages such as complicated processes, easy deposition of heavy metals, and low thermal efficiency. To deal with these problems, we proposed a new glass solidification device based on ultra-high power laser heating to handle HLLW. HLLW was mixed with borosilicate glass, and melting, clarifying, and annealing processes were carried out in a crucible using laser heat. We test the properties of the borosilicate glass solidified body and then analyze it. The results show that the borosilicate glass beads were completely melted and other indicators are in line with the requirements. As a result, the new device that is heated by an ultra-high laser is feasible for vitrification of HLLW and has the potential to overcome the disadvantages of traditional solidification technology. This research is helpful to explore new glass solidification processes.

Effect of Rectangular Fins on Heat Transfer Characteristics of Domestic Cookware

Working process of domestic gas stoves primarily depends on the heat transfer phenomenon between gas flame and the bottom of the cookware. Various energy losses during this heat transfer results in low thermal efficiency. This work focuses on improving heat transfer ability of cookware, thus enhancing thermal-efficiency. Increase in rectangular fin height H causes increase in thermal efficiency value up to a certain limit after which a decreasing trend is observed by both numerical and experimental results. The fin height H=14.6 mm is considered optimum value for thermal efficiency. After H=14.6 mm, the maximum temperature value of fins shows a constant trend up to certain limit. Fin width variation follows a linear increase trend as the width increases up to 5 mm where fluctuation in efficiency stops. Max temperature of fins shows good agreement with increase in fin width in both numerical and experimental values up to W= 4.8 mm after which 10c temp loss occurs due to localized heat losses. Lastly fin spacing is verified against overall thermal efficiency and gradual; decrease is found in efficiency with increasing spacing due to formation of hotspots in between each fin. Lowest efficiency of 57% observed at fin spacing of 7 mm.

Thermo-mechanical efficiency of fibre-reinforced structural lightweight aggregate concrete

The construction industry must consider not only the mechanical performances of structural materials but also their thermal performances for energy-efficient buildings. There exist conflicting thermal and mechanical properties between normal weight concrete (NWC) and lightweight aggregate concrete (LWAC). NWC with high mechanical strength exhibits poor thermal efficiency but LWAC possesses low mechanical strengths but high thermal efficiency. The inclusion of fibres in the mixture of LWAC could provide a solution to its weaknesses in mechanical properties however its thermal performance was not well fully understood. To produce an energy-efficient building material, this study was conducted to determine thermo-mechanical performances of steel (ST) and polypropylene (PP) fibre-reinforced LWACs that meet the structural code requirements with good thermal properties. Lightweight expanded clay aggregate was used to make a structural LWAC and polypropylene and steel fibres were used as the reinforcement. Test results revealed that structural LWAC reinforced ST fibre with 1.0% dosage has the best mechanical and thermo-mechanical efficiency whilst PP fibre with 0.3% dosage has the best thermal performance.The ST fibre has a positive influence on the compressive and tensile strength than PP fibre. In terms of overall thermal performance and cost, LWAC containing 0.3% PP fibre was the most desirable. The PP fibre has a more positive influence on thermal properties than ST fibre. The equations had been proposed with a good correlation of R2 > 0.7979 to predict the thermal properties against density for ST and PP fibres. The new merit Mo equation provides a novel way to measure the thermo-mechanical efficiency of the building materials for the construction industry. ST fibre is better than PP fibre in enhancing the mechanical efficiency but PP fibre is more efficient than ST in enhancing the thermal efficiency of fibre-reinforced LWAC.

An experimental study on a cylindrical-conical cavity receiver for the parabolic dish collector.

Solar thermal energy is a promising solution to the environmental and energy demands issues which the world is faced with them. Among all the solar thermal collectors and solar towers used in this field, parabolic dish collectors are one of the preferable options for researchers due to their high working temperature range and high thermal performance. It has been proved that cavity receivers in solar dish collectors are the best way to achieve the best thermal performance. The main concern in the cavity receivers is their thermal efficiency enhancement by employing different geometries. The hybrid geometry of cylindrical-conical can be used to achieve the high pressure drop and low thermal efficiency of conventional cylindrical and conical cavity receivers, respectively. Furthermore, using proper insulation for the cavity receiver helps to performance enhancement of the dish collector. Ceramic fiber insulation can be suitable for this purpose due to its good thermal properties and fewer environmental issues. Hence, in this study, the objective of efficiency enhancement of parabolic dish collector is followed by utilizing a cylindrical-conical cavity receiver equipped with the fiber ceramic insulation. The results show that ceramic fiber is better insulation than the common mineral wool insulation and can enhance thermal performance by 5.03% on average. In addition, the maximum, average, and minimum thermal efficiencies of the cylindrical-conical cavity receiver by using the ceramic fiber insulation and water as the working fluid were obtained up to 38.77%, 35.19%, and 32.66%, respectively.

Effects of a CFD-improved dimple stepped-lip piston on thermal efficiency and emissions in a medium-duty diesel engine

Diesel piston-bowl shape is a key design parameter that affects spray-wall interactions and turbulent flow development, and in turn affects the engine’s thermal efficiency and emissions. It is hypothesized that thermal efficiency can be improved by enhancing squish-region vortices as they are hypothesized to promote fuel-air mixing, leading to faster heat-release rates. However, the strength and longevity of these vortices decrease with advanced injection timings for typical stepped-lip (SL) piston geometries. Dimple stepped-lip (DSL) pistons enhance vortex formation at early injection timings. Previous engine experiments with such a bowl show 1.4% thermal efficiency gains over an SL piston. However, soot was increased dramatically [SAE 2022-01-0400]. In a previous study, a new DSL bowl was designed using non-combusting computational fluid dynamic simulations. This improved DSL bowl is predicted to promote stronger, more rotationally energetic vortices than the baseline DSL piston: it employs shallower, narrower, and steeper-curved dimples that are placed further out into the squish region. In the current experimental study, this improved bowl is tested in a medium-duty diesel engine and compared against the SL piston over an injection timing sweep at low-load and part-load operating conditions. No substantial thermal efficiency gains are achieved at the early injection timing with the improved DSL design, but soot emissions are lowered by 45% relative to the production SL piston, likely due to improved air utilization and soot oxidation. However, these benefits are lost at late injection timings, where the DSL piston renders a lower thermal efficiency than that of the SL piston. Energy balance analyses show higher wall heat transfer with the DSL piston than with the SL piston despite a 1.3% reduction in the piston surface area. Vortex enhancement may not necessarily lead to improved efficiency as more energetic squish-region vortices can lead to higher convective heat transfer losses.

Sustainable Carbon–Hydrogen–Oxygen symbiosis networks: Intensifying separation sections

The Carbon–Hydrogen–Oxygen symbiosis networks (CHOSYNs) belong to the latest trend of sustainable process design whose main purpose is the efficient use of energy and mass resources. Processes Intensification methodologies have been used to enhance the sustainability of several chemical processes; therefore, this work proposes to involve intensified processes in the synthesis of CHOSYNs to improve the sustainability of the network beyond the integration benefits. The main objective of this work is to evaluate the impact of incorporating intensified processes on the CHOSYN economic, environmental and safety performances. Due to the intensive energy use and low thermal efficiency in distillation sequences, the intensification is focused on these separation processes to improve energy efficiency and reduce operating costs. As a case study is proposed a CHOSYN with conventional processes; thermally couple equivalent configurations are obtained and optimized for suitable distillation sequences of the participant plants, then these sequences are integrated substituting the conventional ones in the final configuration of the CHOSYN. For the conventional and intensified solutions, the variable and fixed costs are determined, the eco-indicator 99 is used to evaluate the environmental aspect, and the safety of the process is assessed by the individual risk.

A global thermal node model for no-load indirect solar dryer

ABSTRACT This paper presents a global thermal node model for predicting heat transfer in no-load indirect solar dryer. The overall influence of the interaction of the indirect solar dryer with the uppermost soil layer is considered. The mathematical model describing the solar drying system with a double-pass air-circulation collector is derived. Based on the Moore and Fisch approach, the soil surface fluxes are calculated using the surface layer similarity theory. The drying air temperature distribution based on dynamic descriptions of the drying environment is studied. The unsteady convection heat transfer results low thermal efficiency of the dryer at low air speed. The linear increase of the inner air speed from to makes the maximum efficiency increases of . When the offsetting air speed undergoes a convex quadratic increase, the average value of the energy efficiency in this case increases of compared to the scenario of constant air speed.

Analysis of Prosopis juliflora Methyl Ester as a Fuel in the CI Engine

As the availability of fossil fuels continues to decrease, the quest for alternative fuels that can be utilised in place of conventional fuels is increasing rapidly. The Prosopis juliflora oil (JFO) is a potential fuel for diesel engines, and the rising availability of the seeds in India, makes it a realistic option for CI engine fuel. In a CI engine, the high viscosity of the oil decreases performance and increase the emission characteristics. Trans-esterification is used to improve the fuel characteristics and reduce the viscosity of the fuel oil. The name for trans-esterified JFO is Prosopis juliflora methyl ester (JFME). Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectrometry (GC–MS) are utilised to determine the species composition of this fuel. C-H stretching alkane group, C=O methyl ester group, CH3 bending alkane group, and C-O stretching ester group are detected by FTIR. According to GCMS, methyl oleate is present at 43.34 percent whereas methyl palmitate is present at 28.99 percent. Both esters have great fuel qualities and JFME is the most suitable fuel for diesel engines. The performance findings demonstrate that JFME has a greater thermal efficiency than JFO and a lower thermal efficiency than diesel. This can be enhanced further by combining various fuels. Keywords: Prosopis juliflora oil, Transesterification, FTIR, GCMS, performance.

Study on reducing carbon dioxide and harmful emissions of diesel-ignited natural gas engine

Natural gas (NG) is a clean and low-carbon fuel and the NG engine is one of the main measures used by the public transportation industry to achieve carbon peak targets. However, NG engines have problems, such as ignition difficulty and low thermal efficiency. The use of diesel to ignite NG is an effective solution to these problems; however, this solution will increase CO2 emissions compared with NG engines. In this study, the potential of reducing CO2 emissions from a diesel-pilot-ignited (DPI) NG engine by optimizing the injection parameters (injection pressure and injection timing) under different loads is studied through experiments. Furthermore, the formation mechanism of CO2 in combination with chemical kinetics is analyzed. The results show that combustion in the DPI mode presents an obvious two-stage heat release and its CO2 emission is 17.15% lower than that of pure diesel combustion (PDC). Under high-load conditions, as the diesel injection pressure increase, the THC and NOX emissions emissions decrease by 67.53% and 84.32%. As the diesel injection timing (DIT) advances, the NOX emissions increase from 1.84 to 22.96 g/kW·h respectively. According to the analysis of the chemical kinetic mechanism, the formation of CO2 in DPI mode is primarily through the reaction of CO + O2 = CO2 + O, whereas in conventional diesel combustion (CDC) mode, CO2 is formed through the reaction of CO + OH = CO2 + H. Within the range of −18 to −5°CA ATDC DIT, increasing the diesel injection pressure (DIP) or advancing the DIT can improve the thermal efficiency of DPI NG engines and reduce CO2 emissions.

TIM: modelling pathways to meet Ireland's long-term energy system challenges with the TIMES-Ireland Model (v1.0)

Abstract. Ireland has significantly increased its climate mitigation ambition, with a recent government commitment to reduce greenhouse gases by an average of 7 % yr−1 in the period to 2030 and a net-zero target for 2050, underpinned by a series of 5-year carbon budgets. Energy systems optimisation modelling (ESOM) is a widely used tool to inform pathways to address long-term energy challenges. This article describes a new ESOM developed to inform Ireland's energy system decarbonisation challenge. The TIMES-Ireland Model (TIM) is an optimisation model of the Irish energy system, which calculates the cost-optimal fuel and technology mix to meet future energy service demands in the transport, buildings, industry, and agriculture sectors, while respecting constraints in greenhouse gas emissions, primary energy resources, and feasible deployment rates. TIM is developed to take into account Ireland's unique energy system context, including a very high potential for offshore wind energy and the challenge of integrating this on a relatively isolated grid, a very ambitious decarbonisation target in the period to 2030, the policy need to inform 5-year carbon budgets to meet policy targets, and the challenge of decarbonising heat in the context of low building stock thermal efficiency and high reliance on fossil fuels. To that end, model features of note include future-proofing with flexible temporal and spatial definitions, with a possible hourly time resolution, unit commitment and capacity expansion features in the power sector, residential and passenger transport underpinned by detailed bottom-up sectoral models, cross-model harmonisation, and soft-linking with demand and macro models. The paper also outlines a priority list of future model developments to better meet the challenge of deeply decarbonising energy supply and demand, taking into account the equity, cost-effectiveness, and technical feasibility. To support transparency and openness in decision-making, TIM is available to download under a Creative Commons licence.

Performance and Emission Characteristics of Jatropha and Dimethoxy-Methane Fuel Blends with EGR in Single Cylinder Water Cooled CI Engine

The number of vehicles on the road has increased by a factor of ten in recent years. As a result of the pollutants emitted by these vehicles on and off the road, ambient air quality has deteriorated significantly. It also increases greenhouse gas emissions as more CO2 is discharged into the atmosphere. As a result, researchers are concentrating on reducing fuel usage and emissions. Because fossil fuel stocks are decreasing, there is an increasing demand for alternative energy. Alternative fuels such as biodiesel and ethanol, which are made from vegetable oil and sugar molasses, are both renewable and environmentally friendly. Blending fuels to increase the combustion qualities of fuel has recently become a viable alternative. A single-cylinder, water-cooled diesel engine with a rated output of 3.7kW at 1500 rpm was used in the tests. We tested diesel, biodiesel and biodiesel with a 10% DMM blend with and without EGR and biodiesel with a 20% DMM blend with and without EGR. Biodiesel with DMM blends has lower thermal efficiency, produces less smoke and emits more NOx. NOx emissions were lowered whereas smoke emissions increased after EGR was used.

Comparative thermal performance enhancement study of a reverse - irradiated and direct - irradiated direct absorption solar collector using silver nanofluid

ABSTRACT Plasmonic nanofluids have emerged as strong candidates for future working fluids in direct absorption solar collectors (DASC). However, in novel DASC systems, a significant temperature gradient exists over working fluid depth increasing emissive losses and hence, results in low thermal conversion efficiency. Considering these issues, a laboratory scale prototype of reverse-irradiated DASC system (RR–DASC) has been tested under controlled laboratory conditions and compared with a direct irradiated DASC system (DR–DASC) using silver nanofluids at three different mass concentrations i.e., 0.1 mg/L, 0.2 mg/L, and 0.4 mg/L. Ag nanoparticles were having monodisperse spherical shape with surface plasmon resonance (SPR) peak occurring around 395–400 nm. The experimental results showed that RR–DASC maintains uniform temperature over the fluid depth, while about 3–4°C temperature gradient was noticed in direct irradiated DASC system under similar operating conditions. A maximum photo-thermal conversion efficiency of about 80% was observed using 0.4 mg/L Ag nanofluids in RR–DASC system. The presented work can pave the ways for future development of highly efficient DASC systems for low to high temperature solar applications.