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

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.

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.

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.

Abstract In the current investigation, viable solar desalting sites in coastal India are identified by detailed thermodynamic and enviro-economic analyses. Mathematical model developed for thermodynamic performance assessment is validated using experiments conducted in inclined solar distillation unit under the climatic condition of Chennai (13.08°N, 80.27°E). Distillation unit produced high quality condensate even from highly saline (40,600 to 60,656 mg/L salinity) feed water. Availability analysis indicated the magnitude of improvement potential, availability destruction, losses and ways for further improvement. Maximum condensate yield, energy and availability efficiency of distillation unit is around 7.09 L/d, 53.45% and 5.39%, respectively for Nellore (one of the east coast locations). Condensate production cost of 18.16 to 32.78 USD/kL and desired availability output of 1.80 to 3.38 kWh/USD invested are observed for the distillation unit at 5.0% interest rate. Maximum yearly average life cycle conversion efficiency, net carbon-dioxide, sulphur-dioxide and nitrous oxide emission alleviated by the unit is around 39.19%, 25.83 tons, 185.73 kg and 75.86 kg, respectively. Viability assessment indicated positive signs for deployment of solar distillation units in 14 locations of coastal India. The proposed solar distillation unit requires lower evaporation area compared to other passive solar distillation units installed in India for the same production capacity.

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 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.

Smart grid is an intelligent power distribution system that employs dual communication between the energy devices and the substation. Dual communication helps to overseer the internet access points, energy meters, and power demand of the entire grid. Deployment of advanced communication and control technologies makes smart grid system efficient for energy availability and low-cost maintenance. Appropriate algorithms are analyzed first for the convenient grid to have proper routing and security with a high-level of power transmission and distribution. Information and Communication Technology plays a significant role in monitoring, demand response, and control of the energy distribution. This paper presents a broad review of communication and network technologies with regard to Internet of Things, Machine to Machine Communication, and Cognitive radio terminologies which comprises 5G technology. Networks suitable for future smart-grid are compared with respect to standard protocols, data rate, throughput, delay, security, and routing. Approaches adopted for the smart-grid system has been commended based on the performance and the parameters observed. ©2019. CBIORE-IJRED. All rights reserved

Thermosyphon is an effective heat transfer device which is widely used all over the world for its ease of use, feasible with different environmental challenges. In this research article, the experimentation with different boiling point of working fluids water and R134a has been used in modified thermosyphon. The modified thermosyphon comprises of the cone frustum attached between the condenser and adiabatic section to hold up for high heat inputs. It is noted from the experiment that the working fluids have unique heat transfer capability with regard to thermal properties for applied heat input. The thermal resistance for different fill ratios with water and R134a in thermosyphon was experimented and the optimality in the fill ratio is identified. Due to the modification in the condenser, R134a condenser performs better for both low and high heat inputs but water works well only in high heat inputs. To predict and compare the temperature outputs at the evaporator, adiabatic and condenser sections of the thermosyphon, machine learning algorithm and optimization technique has been deployed and the output is measures for its accuracy, false positive, predictive positive value and effective performance. It is noted both from the experimental and algorithmic approach that the experiment produces less false positive rate which is ≤ 2% and true positive rate which is ≥ 98%, accuracy of the outputs which are ≥ 98%. The optimized outcome also stabilizes the experimental setup strongly and generates an effective performance rate which is ≥ 95%.

The performance of (Bi₂Te₃-PbTe) hybrid thermoelectric generator (TEG)<strong> </strong>composed of n-type Bismuth Telluride and p-type Lead Telluride semiconductor materials is presented in this paper. <strong> </strong>The effect of different performance parameters such as output voltage, output current, output power, maximum power output, open circuit voltage, Seebeck co-efficient, electrical resistance, thermal conductance, figure of merit, efficiency, heat absorbed and heat removed based on maximum conversion and power efficiency have been theoretically analyzed by varying the hot side temperature of the hybrid thermoelectric generator up to 350^oC and by varying the cold side temperature from 30^oC to 150^oC. The results showed that a maximum power output of 21.7 W has been obtained with the use of one hybrid thermoelectric module for a temperature difference of 320^oC between the hot and cold side of the thermoelectric generator at matched load resistance. The figure of merit was found to be around 1.28 which makes its usage possible in the intermediate temperature (250^oC to 350^oC) applications such as heating of Biomass waste, heat from Biomass cook stoves or waste heat recovery etc. It is also observed that the hybrid thermoelectric generator offers superior performance over 250^oC of the hot side temperature, compared to standard Bi₂Te₃modules.