G. Edison ¹, A. Suresh ², K. Narayana Rao ³

Affiliations
1 School of Mechanical and Building Sciences, VIT University, Vellore-632014
2 Vignan Institute of Technology and Sciences, Hyderabad - 508284, IN
3 Osmania University, Hyderabad - 500007, IN

Abstract

The present paper is concerned with theoretical and experimental study and development of effective suction gas heat exchanger for hermetically sealed compressor. A single tube counter flow heat exchanger had been used, where water itself had been taken as a coolant. Energy consumption parameters as well as COP values have been obtained analytically for both the cases. Energy consumption parameter is 12% less as an average for a heat exchanger attached system compared to the system with out heat exchanger in a time span of 90 minutes. COP values obtained with heat exchanger are firmly better than that of the values with out Heat exchanger. COP values observed to be 7% higher for a heat exchanger coupled system compared to the system with out heat exchanger in the same time span of 90 minutes. In the present scenario where systems optimization is a necessity the present work would be useful in developing a energy efficient system with few modifications. This work would be useful to tackle the heat transfer related issues present in many gas compressors used in pumping and process industries.

Keywords

Suction Line Cooling, Heat Exchanger, COP, Refrigeration, T-S Plot, Density, Refrigerant

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N. Kannan ¹, N. Thirunavukkarasu ², A. Suresh ¹, K. Rajagopal ¹

Affiliations
1 Department of Biotechnology, School of Life Sciences, Vels Institute of Science, Technology and Advanced Studies, Vels University, Chennai - 600117, Tamil Nadu, IN
2 Department of Advanced Zoology and Biotechnology, Dr. Ambedkar Government Arts College, Viyasarpadi, Chennai - 600039, Tamil Nadu, IN

Abstract

Background/Objectives: This study is to collect the samples of true mangrove plant, associated mangrove plants, water and sediments from Ennore Mangrove Ecosystem and the samples are analyzed for heavy metals accumulation. Methods/ Statistical Analysis: The water, sediment and plant materials were collected at 6 locations. After the collection, the plant materials were washed with distilled water and they were dried and acid digested. Further the samples were subjected to analysis of heavy metals by flame atomic absorption spectrophotometer. Triplicate samples were analyzed and their results were expressed in ppm. The statistical analysis ANOVA (Analysis of Variance) and DMRT (Duncan Multiple Range Test) were used. Findings: The maximum concentrations of metals were accumulated (lead-20.93±0.26 ppm/l in water and 48.5±1.44 ppm/g in sediments) in station 4, 5 and minimum concentration (zinc -2.95±0.25 ppm/l in water and 4.36±0.10 ppm/g in sediment) was observed in station 5. In overall average accumulation of heavy metals like Pb (6.09±4.59 ppm/g) > Zn (4.35±3.22 ppm/g) > Cd (3.78±2.80 ppm/g) > Hg (2.84 ± 2.70 ppm/g) > Cr (2.76±2.90 ppm/g) > Cu (0.58 ±0.42 ppm/g) found in the Avicennia marina followed by Pb (4.19±3.13 ppm/g) > Zn (4.12±3.32 ppm/g) > Cd (3.78±2.79 ppm/g) Cr (2.47±1.91 ppm/g) Hg (1.89±1.61ppm/g) > Cu (1.27±1.20 ppm/g) in the Suaeda nudiflora and Pb (4.39±3.23 ppm/g) > Zn (3.77±2.99 ppm/g) > Cd (2.39±1.86 ppm/g) > Cr (1.75±1.34 ppm/g) Hg (0.76±0.74 ppm/g) > Cu (0.50±0.40 ppm/g) in the Sesuvium portulacastrum. The metal concentration of the water and sediments were significantly (p<0.05) varied and in plants, lead (Pb) were significantly varied (p<0.05) between selected plants parts then the other metals like Hg, Cr, Cd, Cu and Zn were not significant. Application/Improvements: Heavy metals contamination was observed in all samples. The mangroves accumulated more concentration than associated mangroves, therefore the Avicennia marina is suitable candidate for bioaccumulator and recommended for phytoremediation.

Keywords

Accumulation, Ecosystem, Ennore, Heavy Metals, Mangroves, Phytoremediation.

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P. Vinoth Kumar ¹, A. Suresh ², M. R. Rashmi ³

Affiliations
1 Department of Electrical and Electrical Engineering, St.Peter’s University, Tonakela Camp Road, Sankar Nagar, Avadi, Chennai - 600 054, Tamil Nadu, IN
2 Department of Electrical and Electrical Engineering, S.A. Engineering College, Poonamallee - Avadi Road, Veeraraghavapuram, Thiruverkadu, Chennai - 600077, Tamil Nadu, IN
3 Department of Electrical and Electrical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham University Campus, Kasavanahalli, Carmelaram, Bengaluru - 560035, Karnataka, IN

Abstract

Objective: The target of this paper is to implement an economical chopper and electrical converter for the hybrid windsolar system. Method: A replacement topology of a mix of CUK and SEPIC convertor is used rather than a private DC/DC convertor. The motor load is provided by victimization the two diodes that connects each wind and solar energy singly or along depending on accessibility. With the improved management in DC/DC convertor and within the electrical converter that associated with the auxiliary circuit in accumulation by the closed-loop system PI controller a more robust control is achieved. Findings: The fused chopper replaced the separate solar and wind choppers and rather than typical electrical converter the novel pulse width modulated electrical converter used supplied with a correct pulse width modulation (PWM) control using 3 equal reference signals. The closed-loop system management is achieved with the digital PI controller and MPPT draws the maximum power from the solar that improves the response with the fast raise in load. The system is validated with MATLAB/Simulink and therefore the output voltage of fused chopper for various solar irradiance and wind speed are tabulated. The output voltage of electrical converter and therefore the motor characteristics are analyzed. Applications/Improvements: For standalone applications within the agriculture water pumping the requirement will satisfy with the hybrid wind solar system.

Keywords

CUK, Fused Chopper, Hybrid Wind Solar System, Maximum Power Point Tracking, Single Ended Primary Inductor (SEPIC).

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S. Priya ¹, A. Suresh ¹, M. R. Rashmi ²

Affiliations
1 Department of Electrical and Electrical Engineering, S. A. Engineering College, Chennai-600054, Tamil Nadu, IN
2 Amita Vishwa Vidyapeetham, School of Egineering, Bangalore-560055, Karnataka, IN

Abstract

Objective: This work discusses with Direct Torque Control (DTC) of Induction motor using 7 Level NPC Multilevel inverter for reducing the complexity in conventional DTC method. Methods: The limitation of traditional DTC scheme is more distortion in torque profile and the mean torque output never meets the torque demand. To get better performance of the traditional DTC a Space Vector Modulation (SVM) technique is projected to meet the torque and flux demands at low speeds. Findings: By designing 7 level NPC for DTC of induction motor and thereby simplifying the classical DTC method and in very particular this paper is minimizing the complications in Torque and Flux control at minimal speeds by decoupling the torque and flux controls and also reduces the ripples in current and torque profile. 7 level NPC is introduced in this paper which helps in eliminating the torque disturbances into minimum. The proposed 7 level inverter uses less number of switches and neutral-point fluctuations are absent in this model. Detached DC supplies are employed for the DC links which carries the ripple current. The proposed inverter topology provided the required magnitudes and phases of voltage and current vectors to meet the desired load values with fewer harmonic content due to superior level inverter and less distortion in torque profile obtained in the closed loop DTC technique. 1 The DTC of Induction Motor simulated by implementing the SVM technique using 7 level NPC and the simulation results are experimentally validated. Improvements: The steady state torque and speed output have less ripple content which reduces the oscillation with a quick response at steady state was investigated.

Keywords

Direct Self Control (DSC), Direct Torque Control (DTC), Multilevel Level Inverter ( MLI), Neutral Point Clamped(NPC), Space Vector Modulation (SVM).

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