Exergy analysis of a flat plate solar collector

In this study, exergetic performance analysis of flat plate solar collector has been carried out analytically. A comprehensive mathematical modelling of thermal performance is simulated using MATLAB simulink and optimal geometrical and thermodynamic parameters are predicted pertaining to optimum performance of the system. The optimization procedure was applied to a typical collector and the optimum design points were extracted. The optimum values of collector inlet temperature, mass flow rate, absorber plate area, and fluid outlet temperature for maximum exergy inflow from the system have been obtained

Exergy analysis of a flat plate solar collector

In this study, exergetic performance analysis of flat plate solar collector has been carried out analytically. A comprehensive mathematical modelling of thermal performance is simulated using MATLAB simulink and optimal geometrical and thermodynamic parameters are predicted pertaining to optimum performance of the system. The optimization procedure was applied to a typical collector and the optimum design points were extracted. The optimum values of collector inlet temperature, mass flow rate, absorber plate area, and fluid outlet temperature for maximum exergy inflow from the system have been obtained

A Taguchi approach for optimization of flow and geometrical parameters in a rectangular channel roughened with V down perforated baffles

This study presents the optimum design parameters of the rectangular channel with V down perforated baffle turbulators using a Taguchi experimental design method. The experimental investigation for the established rectangular channel involves V down perforated baffles attached to the one of the broad wall of the channel having various roughness parameters. The effects of the four design parameters such as Reynolds number, open area ratio, relative roughness height and relative roughness pitch are investigated. In the Taguchi experimental design method, Nusselt number and friction are considered as performance parameter. An L16 (44) orthogonal array is chosen as an experimental plan for the design parameters. The analysis of Taguchi method conducted with the goal of optimization process for minimum friction factor (minimum pressure drop) and maximum Nusselt number (maximum heat transfer) for the designed V down perforated baffle roughened rectangular channel. The optimum configurations of control factors for Nusselt number and friction factor are A2B2C1D4 and A4B1C4D3, respectively. Experimental results validated the suitability of the proposed approach

ANN and RSM approach for modeling and optimization of designing parameters for a V down perforated baffle roughened rectangular channel

The turbulence promoters are widely used to enhance the performance of rectangular channel which were used for turbine blade passage cooling. In the present study, the influence of design parameters of the V down perforated baffle roughened rectangular channel on the heat transfer and friction factor was investigated using RSM and ANN. The quadratic model generated by RSM is used to predict the performance parameters, i.e. Nusselt number and friction factor with reasonably good accuracy. The optimum values of the design parameters of the V down perforated baffle roughened rectangular channel are relative roughness pitch of 2.6, relative roughness height of 0.33, open area ratio of 18% and Reynolds number of 18,500, in the desirable range of the order of 0.95. The training of the experimental data is carried out using 4-10-2 neural network and the predicted values are compared with the experimental values and found deviation in the range of ±10% among predicted and experimental values. The comparison of predicted values by RSM and ANN with the experimental values was carried out for each run of experiment and it was observed that the RSM predicted values are in accord with the experimental values in the uncertainty range of ±5%

Comparative study for thermal-hydraulic performance

Several researchers have worked on the passive approach of heat transfer enhancement in tube heat exchangers. Some of them tried to modify the surface by creating dimple or using wire coil of different cross-section, while some worked on core fluid disturbance by using some insert geometries such as twisted tapes. But the ultimate aim of all was to create some disturbance in the flow in order to obtain enhanced heat transfer. This paper focuses on comparison of some of the most commonly used insert geometries. Insert geometry selected for this comparison is collection of core fluid disturbance, surface modification and combination of both. Different geometries taken in this study include twisted tape, twisted tape with ring, circular band, multiple twisted tape, twisted tape with conical rings, and so on and used air under turbulent flow regime as working fluid. On the basis of comparison made, it is observed that, in case of “single twisted tape insert” the thermal performance factor was maximum and in the event of “twisted tape with circular ring” the overall heat transfer rate is maximum. Future aspect is also proposed, which includes perforation in circular ring, and causes decrease in friction factor value because of less flow blockage

Economic analysis of artificially roughened solar air heater with v-shaped ribs

Due to the minimal transfer of heat from absorber plate to moving air in the duct, solar air heaters have low performance. One of the procedures to augment the heat transfer by substantial amount is by utilizing artificial roughness, by which the performance can be improved considerably. In this study, an economic investigation of solar air heater embedded with artificial roughness is accomplished numerically employing v-shaped roughness, with the objective of optimising life cycle solar savings. The non-dimensional parameters of roughness, namely, angle of attack (α), roughness pitch (p/e) and roughness height (e/Dh) are examined by varying temperature rise over the solar air heater (∆T) and solar radiations (I) for different economic parameters values i.e., cost of collector, cost of roughness elements, and cost of conventional fuel

Characterization of a Nb-Pb composite target

A thin Nb target on a Pb backing was fabricated using the rolling technique. In the present work, the characterization of the sample has been carried out using various techniques to study the surface morphology, crystallography, elemental analysis, thickness and electrical conductivity useful for the intended use of the target prepared. The thin Nb target was analyzed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Rutherford back-scattering spectroscopy (RBS) techniques. The uniform and smooth surface of the sample was confirmed by SEM imaging. The presence of oxygen in the EDS spectra and peaks corresponding to crystal planes of PbO2 in the XRD spectrum confirms the oxidation of Pb foil. The XRD spectrum shows clear peaks corresponding to (011), (002), (112) crystal planes of pure Nb. The thickness of the thin Nb foil measured using the RBS techniques was found to be 0.8 mg/cm2. The current(I)-voltage(V) curve (relationship between the current flowing through an electronic device and the applied voltage across its terminals) at room temperature for the Pb and Nb/Pb foils was plotted and showed linear relationship between applied voltage and current flowing through the target foil. The measured electrical conductivity indicates an enhancement of 35.9 % for Nb/Pb foil relative to the conductivity measured for the Pb foil