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Second law optimization and parametric study of a solar air heater having artificially roughened absorber plate

Sahu Mukesh Kumar, Prasad Radha Krishna

Archives of Thermodynamics

2019

Vol. 40, no 2

107--135

In present article a mathematical model of arc shape wire roughened solar air heater, on the basis of energy and exergy output rates, entropy generation rate and augmentation entropy generation number, has been developed. A parametric study leading to entropy generation minimization has also been performed. In the analysis the geometric and operating parameters which have been considered as variable are: inlet air temperature, duct depth, collector width to duct depth ratio, mass flow rate per unit collector area, and temperature rise parameter. Results have been presented to see the effects of these values on the energy and exergy output rates of the roughened solar air heater. Effect of different values of wire rib roughness parameters on entropy generation has also been presented. Finally, design curves and optimization for different rib roughness parameters on the basis of minimum entropy generation number with temperature rise parameter, have been presented and optimum values also have been found out 0.004 to 0.010 (Km2 )/W. The entropy generation rate obtained for the system, in the present work has been compared with those obtained for solar air heater with different roughness geometries on absorber plates available in the literature for common roughness parameters and operating parameters which validate the present results.

Analiza procesu stacjonarnego przepływu ciepła na podstawie zasady minimalizacji generowania entropii

Hołda A.

Rudy i Metale Nieżelazne

2008

R. 53, nr 5

275-281

W artykule porównano dwa przypadki przewodzenia ciepła w izolacji termicznej, problem klasyczny oraz minimalizujący generację entropii. Jako kryterium porównawcze wybrano wielkość ciepła odpadowego. Pokazano wpływ minimalizacji źródeł entropii przy przewodzeniu ciepła na bilans energetyczny procesu technologicznego. Rozważania poparto przykładami obniżającymi źródła entropii w izolacji.

Comparison of the solution of two different boundary-value problems of heat conduction in solid isolation has been presented. The solution of the classical formulation of steady state problem and solution based on the entropy generation minimization principle are analyzed. Waste heat flow to surrounding has been chosen as the comparison criterion. Influence of the minimization of entropy generation an the energy balance and thermodynamic efficiency of the technological process has been shown. Theoretical considerations have been illustrated with numerical example.