Wyniki wyszukiwania - BazTech

1

Theoretical investigation for optimal thermal and thermodynamic performance of flat-plate solar collector with nanofluids

Gorai Vikash Kumar, Kumar Mukesh, Singh Rahul, Sahu Mukesh Kumar

Archives of Thermodynamics

|

2025

|

Vol. 46, no. 1

155--167

EN

In this work, an analytical study is carried out on the performance of copper-based nanoparticles and water in flat-plate solar collectors. The effect of copper-based nanoparticles on various thermophysical properties of collectors has been studied and compared with water under the same conditions. The effects of temperature rise parameter from 0.0018 to 0.025, volume percentage of nanoparticles from 0 to 1 and mass flow rate in the range of 0.012 to 0.170 kg/s have been considered. The mass flow rate range covers both laminar and turbulent flow conditions. A detailed parametric study was carried out by developing appropriate MATLAB codes for various performance and energy equations to investigate the effects of volume percentage of nanoparticles and mass flow rate on the basic thermophysical properties and performance parameters, including Nusselt number, heat transfer coefficient, collector plate factor, heat removal factor, Reynolds number, collector heat gain, fluid outlet temperature and thermal efficiency. A new number has been introduced to find out the optimal value of mass flow rate for optimizing collector performance. From the analysis it was found that water collector achieved the maximum thermal efficiency of 53.7% for the highest value of mass flow rate of 0.1675 kg/s. For the nanofluid collector, the maximum efficiency is 70.5% for a nanofluid volume fraction of 0.48 and for the highest considered value of mass flow rate of 0.1675 kg/s. The nanofluid collector is predicted to provide up to 16.8% higher energy efficiency than the water collector.

2

Optimization of geometric and flow parameters of solar air heater roughened with artificial roughness by Taguchi method

Sahu Mukesh Kumar, Mishra Shivam, Kumar Avinash

Archives of Thermodynamics

|

2023

|

Vol. 44, no. 3

3--33

EN

The paper presents the investigation of the optimum design parameters of a solar air heater (SAH) having wire ribs as artificial roughness by using the Taguchi method. The solar air heater has arc shape roughness geometry with apex upstream flow on the absorber plate. The objective of this paper is to obtain a set of parameters that deliver maximum thermo-hydraulic performance. For this objective, a new parameter the thermo-hydraulic improvement parameter (ηTHIP), has been introduced. For the present analysis, the effects of Reynolds number (Re), relative roughness pitch (P/e), angle of attack (α), and relative roughness height (e/Dh), denoted by A, B, C, and D, respectively, have been considered. An (L18 = 61 · 3 2 ) orthogonal array (OA) was chosen as an experimental plan for applying the Taguchi method. The set of control factors for the solar air heater SAH which delivers the maximum Nusselt number (Nu), and minimum friction factor (fr) – are A6B2C2, and A1B1C3 respectively. To obtain the maximum THIP the experimental set-up requires only one single run using the parameter A6B2C2, hence there is no need to run it all 54 times.

3

Experimental investigation of augmented thermal and performance characteristics of solar air heater ducts due to varied orientations of roughness geometry on the absorber plate

Sahu Mukesh Kumar, Matheswaran M. M., Bishnoi Pardeep

Archives of Thermodynamics

|

2020

|

Vol. 41, no. 3

147--182

EN

This paper presents the outdoor experimental results for thermal performance analysis of artificially roughened solar air heaters (SAHs). Circular wire ribs have been arranged to form arc shape geometry on the absorber plates and have been tested for two configurations of SAHs named as arc shape apex-downstream flow and arc shape apex-upstream flow SAH. Roughness parameters have been taken as relative roughness pitch in the range of 8–15, angle of attack 45°–75°, and for fixed relative roughness height of 0.0454, duct width to duct height ratio of 11. During the experimental analysis the mass flow rate varied from 0.0100 to 0.0471 kg/s. Based on the experimental results it was found that roughness with apexupstream flow SAH is having higher value of thermal efficiency, heat removal factor and collector efficiency factor as compared to roughness with apexdownstream flow SAH and simple absorber plate SAH. In the range of the operating parameters investigated the maximum of thermal efficiency, heat removal factor, and collector efficiency factor have been found.

4

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

EN

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.