• Energy Research
• 7. Clean energy close
• Karunya University close

Abstract Advanced third generation biofuels like pyrolysis oil generated from waste biomass paves way for a cleaner and sustainable environment. An experimental-cum-statistical analysis was performed with the aim of determining the optimal engine operating conditions (with respect to compression ratio, load and fuel blend) to enhance the engine operating characteristics (performance and emission) of a diesel engine. Multiple regression models designed by using response surface methodology (RSM) for the output response variables like brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), oxides of carbon (CO&CO2), hydrocarbon (HC), oxides of nitrogen (NOx) and smoke opacity were found to be statistically significant by analysis of variance. Optimization was carried out using desirability approach with a target of maximizing BTE and CO2 simultaneously by minimizing all other responses. From the results, it can be observed that the optimum conditions for bio-oil operation were 18:1 compression ratio, 20% fuel blend and 100% load. The models developed by RSM were validated through confirmatory experiments and found that the models were satisfactory to report the influence of compression ratio, load and bio-oil concentration on the operating characteristics of the diesel engine as the error in prediction is within 5%.

Abstract In today's world, where fuel prices in all modes of transport are skyrocketing, car manufacturers must find better and innovative ways to make their cars more energy efficient. A reduction in fuel consumption of a vehicle directly corresponds to the non- renewable fossil fuels' lesser consumption and a decrease in vehicular pollution. All road vehicles under driving conditions are made to pass through a wall of air around them and displace this air envelope as efficiently as they can depend upon the vehicle's shape and frontal area. As it flows around the car, this air envelope is responsible for drag force, which is the main opposition to the vehicle's forward motion. This drag force is proportional to the square of the velocity of the car and as a result, increases significantly after certain speeds. In most passenger vehicles due to constraints created by cabin space, regulations, etc., the cars end up being somewhat obliquely and boxy shaped, leading to turbulence, particularly towards the rear end of the car. This formation of turbulence results in flow separation at a point near the vehicle's rear windshield, which causes the boundary layer to not adhere to the body surface, expand and create a high-pressure region which induces drag along this portion of the vehicle. When placed at the specific distance upstream of the flow separation point, the vortex generators play a pivotal role in reducing drag and lift. And coupled with a rear wing can give suitable downforce values and drag reduction by redirecting the flow of air at the right angle of approach to the wing and preventing flow separation. The drag reduction is obtained by changing the angle of attack of the airstream with the wing by changing the orientation of vortex generators.

Kerosene based hydrocarbon fuels are preferred candidates for the source of energy due to its stable properties. Based on the requirement of the combustor and the growing concern over pollutant, kerosene based fuels are modified. The fuel under investigation is a modified form of kerosene with ultra-low sulphur content. The effect of temperature on modified kerosene is studied for viscosity, surface tension, specific heat, density and ignition delay. The time delay for ignition of gas-phase mixtures of modified kerosene/oxygen have been measured using a shock tube facility. The experiments are conducted in the temperature range of 1200–1877 K, pressure range of 4–12 atm and equivalence ratio of Ø = 1.5, 1 and 0.5. The ignition delay time measurements were carried out using piezoelectric pressure transducers, which records the pressure rise due to ignition and simultaneously recording the light emission during the process of ignition using a photodiode. The ignition delay is represented as τign = 0.168841 × P−1.49 × Ø0.72 × e(14310/T)

Abstract The employments of Multilevel DC Link Inverters offer dependable points of interest attributable to the expansion in the highest levels at the yield output voltage and are broadly acknowledged for industrial applications. The execution of these bores on high when contrasted with the routine conventional two-level inverters because of their drawbacks. Be that as it may, the expanded number of devices, complex PWM control, and voltage-adjusting issue are a portion of the hindrances. This paper goes for presenting another topology, which can perilously decrease the switch number by introducing a module called polarity generation module. This topology gives a DC voltage fit as a fiddle of a staircase which approximates the corrected state of a directed sinusoidal wave to the extension inverter, which thusly interchanges the extremity to deliver an AC voltage with low THD and switching loss. The topology is tested by adopting a choice of control techniques and enhanced execution of the proposed inverter contrasted with the overarching topologies. The FPGA has been selected to verify the proposed inverter with modulating technique due its advanced futures and computing facility. For validation, simulation and experimental results are offered.

Abstract Photovoltaic power plants pose challenges when integrated with power grid. The PV plants always focus on extracting maximum power from arrays. A new technique for tracking a pseudo-maximum power point for creating power reserve is presented. By using developed fractional open circuit voltage algorithm power is extracted from the array and continuously power is supplied to load as well as for charging the battery. In this project a 12V, 7Ah battery is used for charging and to avoid the revise current flow from the battery when input is, diode is replace by MOSFET which will stop the reverse current .Generally in other algorithm will trace the power when maximum input is coming for that time power circuit is disconnected from the load. In this case power developed algorithm is connected to designed moderate power five switch synchronous algorithm and operates in pseudo-operation which will continuously supply the power to charge the battery. This can be control by using PIC microcontroller which will generate the pulses and track the PV power. Precise measurement in the steady state shows that the converter finds the maximum power point with tracking 95.85%.

This study involves the application of new phase separated biological pretreatment (PSBP) strategy on microalgal biomass using the nickel nanoparticle induced cellulase secreting bacterial disintegration. Particularly, interest was focussed on cell wall weakening (CWW) of microalgae biomass besides the cell disintegration (CD) and release of organics. During CWW, protein, carbohydrate, cellulose, hemicellulose and DNA were used as evaluation indexes. Similarly, during CD, soluble chemical oxygen demand was used as evaluation index to assess the disintegration effect. A higher CWW was achieved at nickel nanoparticle (Np) dosage of 0.004 g/g SS. During CD, a clear demarcation in biomass solubilisation was achieved by PSBP (36%) than the sole biological pretreatment -BP (24%). The biomethanogenesis test results showed that enhanced methane production of 411 mL/g COD was achieved by PSBP than BP. Energy analysis showed that a higher net energy production of 6.467 GJ/d was achieved by PSBP.

Activated mesoporous carbon obtained from spent mushroom compost as a catalyst support provides enhanced long-term durability during the oxygen reduction reaction.

The increase in the population creates an increased demand for construction activities with eco-friendly, sustainable, and high-performance materials. Insulated concrete form (ICF) is an emerging technology that satisfies the sustainability demands of the construction sector. ICF is a composite material (a combination of expanded polystyrene (EPS) and geopolymer concrete (GPC)) that enhances the performance of concrete (such as thermal insulation and mechanical properties). To investigate the axial strength performance, five different types of prototypes were created and tested. Type I (without reinforcement): (a) hollow EPS without concrete, (b) alternative cells of EPS filled with concrete, (c) and all the cells of EPS filled with concrete; and Type II (with reinforcement): (d) alternative cells of EPS filled with concrete; (e) and all the cells of EPS filled with concrete. Amongst all the five prototypes, two grades of GPC were employed. M15 and M20 grades are used to examine the effectiveness in terms of cost. For comparing the test results, a reference masonry unit was constructed with conventional clay bricks. The main aim of the investigation is to examine the physical and mechanical performance of sandwich-type ICFs. The presence of polystyrene in ICF changes the failure pattern from brittle to ductile. The result from the study reveals that the Type II prototype, i.e., the specimen with all the cells of EPS filled with concrete and reinforcement, possesses a maximum load-carrying capacity greater than the reference masonry unit. Therefore, the proposed ICF is recommended to replace the conventional load-bearing system and non-load-bearing walls.

Abstract Entropy generation analysis of hybrid nanofluid in a two pass multiport minichannel heat exchanger coupled with a thermoelectric cooler is experimentally investigated. Alumina (Al2O3, 50 nm), graphene (5 nm) and the hybrid of these two in equal portions with 0.1% volume concentrations is separately dispersed in to the base fluid and tested. The hydraulic diameter and aspect ratio of the channel are 1.184 mm and 0.689 respectively. The heat flux is varied from 6250 W/m2 to 25,000 W/m2 and the flow regime is considered to be laminar with the Reynolds number varying from 200 to 1000. The results showed an enhancement of 17.32% in cooling capacity and coefficient of performance (COP) with the use of pure graphene–water nanofluid when compared with that of the other tested combinations of nanofluids. Total entropy generation decreased from 0.0361 W/K to 0.0184 W/K with increase in Reynolds number from 200 to 1000 for the maximum applied heat flux of 25,000 W/m2. Similarly an enhancement of 88.62% in the convective heat transfer coefficient and a reduction of 4.7 °C in the device temperature are achieved when pure graphene–water nanofluid is used as the coolant. Among the tested nanofluids, graphene–water nanofluid shows better performance in terms of heat transfer, thermodynamic and exergic analysis.