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

Sustainable desalination can be achieved by adopting renewable energy-based low-cost and low-impact desalting techniques. In this investigation, capability of inclined felt sheet solar distiller in desalting seawater is assessed by evaluating its performance, distillate water quality, economics, and environmental impacts. The distiller with 1.18-m2 aperture area produced around 4.60 L/day of distillate for a cumulative incident solar radiation intensity of about 20.52 MJ/m2 day. Its pollutant removal efficiency is very much superior to other available solar stills reported in literatures. Thermal model developed for estimating distiller's performance is able to predict its productivity with reasonable accuracy (only 8.0% deviation from experimental values) and was used for estimating distiller's performance in various seashore locations in India with varying clear days (191 to 246). Yearly mean distillate production and thermal and exergy efficiencies of the proposed distiller range between 3.60 to 4.50 L/day, 36.45 to 42.39%, and 2.85 to 3.65%, respectively, in east seashore locations of India. Moreover, 18.46 tons of CO2, 132.72 kg of SO2, and 54.20 kg of NO emission can be mitigated by adopting the distiller for potable water production. Distillate production cost of inclined felt sheet solar distiller is in the range of 1.15 to 2.29 INR/L and highly depends on the interest rate at which the distiller is financed. Generation of reasonable quantity of high-quality potable water at low cost with huge environmental benefits makes proposed inclined felt sheet solar distiller a suitable option for quenching thirst in coastal and remote locations.

The thermal performance of a compact loop heat pipe is fabricated and tested for different heat inputs ranging from 30 W to 500 W using water and silver-water nanofluid with low volume concentrations of silver nanoparticles (0.03% and 0.09%) in vertical orientation. A flat square evaporator having a bottom area of 30 mm × 30 mm and a height of 15 mm is used in the present study. The effect of heat input on the thermal resistance, evaporation and condensation heat transfer coefficient is experimentally investigated. The results showed that a reduction in the evaporator thermal resistance of 26.45% is achieved with 0.09 volume percentage of silver nanoparticles when compared with that of water. Further an enhancement in the convective heat transfer coefficient of 25.23% has been observed with the same volume concentration of silver nanoparticles. Addition of small amount of nanoparticles enhanced the operating range of heat pipe beyond 500 W and without the occurrence of any dry out conditions. From the outcome of this study, it is concluded that the compact loop heat pipe with flat square evaporator can be used for thermal control of electronic equipments with limited space.

Abstract The dwindling of natural resources such as crude oil, coal etc. has made it essential to switch over to biodiesel. Biodiesel has a number of properties which are beneficial to the environment. The main advantage of biodiesel is that it's carbon neutral and it does not create carbon dioxide (CO2). In addition, it leads to a decrease in pollution by reducing the emission of harmful and hazardous substances to the atmosphere and greatly improves the engine performance. This paper puts forward a comprehensive assessment of biodiesel production from various non-edible oils such as waste fried oil, pyrolysis oil, preheated palm oil, waste cooking oil, jatropha oil, karanja oil etc. It also serves as an index to measure combustion, performance and emission characteristics in a variable compression ratio (VCR) diesel engine, where biodiesel is blended with diesel. The need for switching over to VCR engine is that it provides better fuel efficiency, up to 30% reduction in fuel consumption, better control at peak cylinder pressure, ability to use multi-fuel and reduction in the exhaust emissions when compared to that of a constant compression ratio diesel engine.

Abstract This paper evaluates the accuracy of Support Vector Machine (SVM), Artificial Neural Network (ANN) and empirical solar radiation models with different combination of input parameters. The parameters include month, latitude, longitude, bright sunshine hours, day length, relative humidity, maximum and minimum temperature. The models are evaluated based on statistical measures. Four new empirical models are introduced and validated with experimental data. This work is focused on the prediction of monthly mean daily global solar radiation (GSR) for different cities in India with most influencing input parameters identified using Waikato Environment for Knowledge Analysis (WEKA) software. WEKA identifies month, latitude, maximum temperature and bright sunshine hours as the most influencing and relative humidity as the least influencing input parameter. SVM model with most influencing input parameter performs better than ANN and Empirical models. Exclusion of relative humidity does not affect the prediction accuracy. Therefore this work reduces the dimensionality of the data and improves the prediction accuracy. This work also attempts in assessing the solar energy potential of smart cities of Tamil Nadu, India using the SVM model. The predicted annual GSR varies from 17 to 22 MJ/m2/day which is precise enough for a wide range of solar applications.

Le potentiel de solubilisation du prétraitement biologique des boues activées résiduaires (WAS) est limité en raison de sa structure en flocs. Les substances polymères supplémentaires (EPS) sont responsables de la formation de flocs. Dans cette enquête, une tentative a été faite pour perturber la structure des flocs de WAS en éliminant les EPS à travers le disperseur. Dans la première étape, le traitement du disperseur a libéré 242 mg/L d'EPS soluble à 3000 tr/min avec la durée des années 50 et provoque une défloculation de L'IS. Au cours de la deuxième étape, les boues défloculées ont été soumises à un prétraitement bactérien afin d'évaluer l'effet de la perturbation des flocs. Au cours du prétraitement bactérien, il a été constaté que les boues défloculées produisaient une solubilisation organique plus élevée de 23,9 % et une réduction des solides en suspension de 19,1 %, par rapport au témoin (10,2 %) et (8,7 %), respectivement. Un rendement en biogaz de 220 mL/g de DCO a été enregistré dans les boues défloculées et de 93 mL/g de DCO dans les boues floculées. De ce qui précède, il est évident que la défloculation a efficacement amélioré le prétraitement bactérien conduisant à plus de solubilisation et de production de biogaz. El potencial de solubilización del pretratamiento biológico para los lodos activados residuales (WAS) es limitado debido a su estructura de flóculos. Las sustancias extra poliméricas (eps) son responsables de la formación de flóculos. En esta investigación, se ha intentado perturbar la estructura del flóculo de WAS mediante la eliminación de eps a través del dispersador. En la primera etapa, el tratamiento dispersor liberó 242 mg/L de eps soluble a 3000 rpm con la duración de los 50s y provoca la desfloculación de WAS. En la segunda etapa, el lodo desfloculado se sometió a un pretratamiento bacteriano para evaluar el efecto de la interrupción del flóculo. Durante el pretratamiento bacteriano, se encontró que los lodos desfloculados produjeron una mayor solubilización orgánica del 23,9% y una reducción de sólidos en suspensión del 19,1%, en comparación con el control (10,2%) y (8,7%), respectivamente. Se registró un rendimiento de biogás de 220 ml/g de DQO en lodo desfloculado y 93 ml/g DE DQO en lodo floculado. De lo anterior, es evidente que la desfloculación mejoró efectivamente el pretratamiento bacteriano, lo que condujo a una mayor solubilización y producción de biogás. The solubilisation potential of biological pretreatment for waste activated sludge (WAS) is limited due to its floc structure. Extra polymeric substances (EPS) is responsible for floc formation. In this investigation, an attempt has been made to disturb floc structure of WAS by removing EPS through disperser. In first stage, disperser treatment released 242 mg/L of soluble EPS at 3000 rpm with the duration of the 50s and causes deflocculation of WAS. In second stage, deflocculated sludge was subjected to bacterial pretreatment to assess the effect of floc disruption. During bacterial pretreatment, it was found that deflocculated sludge produced higher organic solubilization of 23.9% and suspended solids reduction of 19.1%, when compared to control (10.2%) and (8.7%), respectively. A biogas yield of 220 mL/g COD was recorded in deflocculated sludge and 93 mL/g COD in flocculated sludge. From the above, it is evident that deflocculation effectively enhanced bacterial pretreatment leading to more solubilization and biogas production. إن إمكانات الذوبان للمعالجة المسبقة البيولوجية للحمأة المنشطة بالنفايات (WAS) محدودة بسبب هيكلها. المواد البوليمرية الإضافية (EPS) هي المسؤولة عن تكوين الندف. في هذا التحقيق، بُذلت محاولة لإزعاج هيكل التدفق عن طريق إزالة EPS من خلال الموزع. في المرحلة الأولى، أطلق العلاج بالمشتت 242 مجم/لتر من EPS القابل للذوبان عند 3000 دورة في الدقيقة مع مدة الخمسينيات ويسبب التلبد. في المرحلة الثانية، تعرضت الحمأة المفرغة للمعالجة البكتيرية المسبقة لتقييم تأثير اضطراب التدفق. أثناء المعالجة المسبقة للبكتيريا، وجد أن الحمأة المفرغة أنتجت ذوبانًا عضويًا أعلى بنسبة 23.9 ٪ وانخفاضًا في المواد الصلبة العالقة بنسبة 19.1 ٪، عند مقارنتها بالسيطرة (10.2 ٪) و (8.7 ٪)، على التوالي. تم تسجيل ناتج غاز حيوي قدره 220 مل/جم COD في الحمأة التي تم تفريغها و 93 مل/جم COD في الحمأة التي تم تلبدها. مما سبق، من الواضح أن إزالة التلبد عززت بشكل فعال المعالجة المسبقة للبكتيريا مما أدى إلى المزيد من الذوبان وإنتاج الغاز الحيوي.

Abstract A comprehensive review of cylindrical two-phase closed thermosyphon for low-temperature applications is presented in this paper. The review of literature based on the experimental studies of two-phase closed thermosyphon is categorized according to the utilization of refrigerants, nanofluids, external parameters, surface coating and modifications in the design of two-phase closed thermosyphon to provide a useful reference to the researchers in the field of cylindrical two-phase closed thermosyphon. The effect of geometrical parameters, power input, working fluid, inclination angle and fill ratio on the performance of thermosyphon has been studied thoroughly. The outcome of this review paper would help the research community to enhance the thermal efficiency of cylindrical two-phase closed thermosyphon. It would emphasize the need for utilization of environment-friendly refrigerants in two-phase closed thermosyphon, powered by a solar photovoltaic system, as these two would not affect the environment.

Abstract In recent years design of micro hydro power plants has been examined by various groups throughout the world due to its merits of offering better performance than the conventional fossil fuels to meet the energy need. Considering the portfolio of energy, the improvement of hydro power will partake in decrease of greenhouse gas emission and better malleability in the grid operation. This inquisition study examined the turbine of small hydro plant from the perspective of efficiency improvement while maintaining the global cost of the project per kW arrive within confined range. In this documentation an extensive epitomize of turbines available in India and other countries has been described. The selection of head, runner diameter along with its accomplishment are also presented. This study reveals an improvement for the design of turbines while comparing the functioning of other existing system for similar operating condition. Since most power plants now-a-day's use large turbines for the low power production, losses and overall cost increases, hence this survey will be helpful to reduce the cost of the plant. The reviews mainly focus on the study of existing turbines upto 100 kW. The importance of the turbine in micro hydro projects with respect to our current energy scenario is also highlighted.

Wireless Sensor Network (WSN) has an enormous scope of utilizations in detecting different parameters such as temperature, pressure, sound, pollution, etc. The sensed data in each sensor node are a valuable one. To communicate the information to the base station for further processing, a lot of strategies are available. Each sensor senses the data in different sampling rate depending upon the sudden raise in the sensing parameters. Data communication to the base station is very critical due to the dynamicity of the environment during the stipulated time.The sensed data should reach the base station before the data becomes invalid due to the violation of the deadline. In order to avoid deadline violation so that the sensed data becomes useless, this paper proposing a novel data collection algorithm based on the popular Earliest Deadline First (EDF) scheduling algorithm. The various simulation parameters are taken into account to verify the performance of the proposed method and the result shows that it achieves high throughput, low delay, high Packet Delivery Ratio (PDR) and low energy consumption.

Economically viable production facilities for microalgae depend on the optimization of growth parameters with regard to nutrient requirements. Using microalgae to treat industrial effluents containing heavy metals presents an alternative to the current practice of using physical and chemical methods. Present work focuses on the statistical optimization of growth of Chlorococcum humicola to ascertain the maximum production of biomass. Plackett Burman design was carried out to screen the significant variables influencing biomass production. Further, Response Surface Methodology was employed to optimize the effect of inoculum, light intensity and pH on net biomass yield. Optimum conditions for maximum biomass yield were identified to be inoculum at 15%, light intensity to be 1500lx and pH 8.5. Theoretical and predicted values were in agreement and thus the model was found to be significant. Gas chromatography analyses of the FAME derivatives showed a high percentage of saturated fatty acids thereby confirming the biofuel properties of the oil derived from algal biomass.