Experimental study on thermal efficiency improvement using nanofluids in heat sink with heated circular cylinder

Author(s):  
Cong Qi ◽  
Keao Li ◽  
Chunyang Li ◽  
Bichen Shang ◽  
Yuying Yan
Author(s):  
Vijayakumar Rajendran ◽  
Harichandran Ramasubbu ◽  
Karthick Alagar ◽  
Vignesh Kumar Ramalingam

An experimental study has been carried out to enhance a solar air heater’s performance by integrating artificial roughness through baffles on the absorber plate. In this paper, the thermal and energy matrices analysis of a Solar Air Heater (SAH) roughened with V up perforated baffles have been investigated. The effect of various mass flow rates on the SAH was analyzed with and without baffles. Experimental outputs like outlet air temperature, useful energy (heat) gain and thermal efficiency were evaluated to confirm the performance improvement. The baffled absorber plate SAH was found to give the maximum thermal efficiency and useful energy gain of 89.3% and 1321.37 W at a mass flow rate of 0.0346 kg/s, 13% and 12% higher than SAH without baffle. This result showed that the V up-shaped ribs in flow arrangement provide better thermal performance than smooth plate SAH for the parameter investigated. Energy matrices analysis and carbon dioxide mitigation of the SAH system were also analyzed.


Author(s):  
Chun K. Kwok ◽  
Matthew M. Asada ◽  
Jonathan R. Mita ◽  
Weilin Qu

This paper presents an experimental study of single-phase heat transfer characteristics of binary methanol-water mixtures in a micro-channel heat sink containing an array of 22 microchannels with 240μm × 630μm cross-section. Pure water, pure methanol, and five methanol-water mixtures with methanol molar fraction of 16%, 36%, 50%, 63% and 82% were tested. Key parametric trends were identified and discussed. The experimental study was complemented by a three-dimensional numerical simulation. Numerical predictions and experimental data are in good agreement with a mean absolute error (MAE) of 0.87%.


2014 ◽  
Vol 592-594 ◽  
pp. 1423-1427 ◽  
Author(s):  
G. Kumaresan ◽  
S. Venkatachalapathy ◽  
Indraneel C. Naik

This study aims to investigate the influence of inclination angle and concentration of nanoparticles on the improvement in heat pipe thermal efficiency. Spherical shaped, 40 nm size CuO nanoparticles are used in this study and its physical and thermal chracteristics are investigated. The results are compared with a heat pipe using DI water at horizontal position.The thermal efficiency is improved by increasing the tilt angle and mass of particles dispersed in DI water. The improvement in thermal efficiency obtained are 20.59, 35.92 and 32.57% respectively for 0.5, 1.0 and 1.5 wt% of CuO nanofluids and 60° inclination angle.


2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 487-494 ◽  
Author(s):  
Aminreza Noghrehabadi ◽  
Ebrahim Hajidavaloo ◽  
Mojtaba Moravej ◽  
Ali Esmailinasab

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi?mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (?61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate.


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