Estimation of convective heat transfer coefficient in a single-slope solar still: a numerical study

2012 ◽  
Vol 50 (1-3) ◽  
pp. 387-396 ◽  
Author(s):  
Nader Rahbar ◽  
Javad Abolfazli Esfahani
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Numerical Study ◽  
Convective Heat Transfer Coefficient ◽  
Solar Still

Analytical Study of Thermo-Physical Performance of Nanofluid Loaded Hybrid Double Slope Solar Still

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Lovedeep Sahota ◽  
V. S. Gupta ◽  
G. N. Tiwari
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Hybrid System ◽  
Base Fluid ◽  
Convective Heat Transfer Coefficient ◽  
Solar Still

In the present paper, efforts has been made to study the thermophysical performance (properties) of N photovoltaic thermal flat plate collectors coupled with double slope solar still (N-PVT-FPC-DSSS) and operating with helically coiled heat exchanger. The analysis has been performed for the optimized concentration of NPs (Al2O3 0.107%; TiO2 0.093%; and CuO 0.131%) and optimized basin fluid (base fluid/nanofluid) mass (50 kg) for different weather conditions of the month May (New Delhi). The Nusselt number (Nu) and Rayleigh number (Ra) are functions of thermophysical properties of nanofluids and strongly influence the natural convective heat transfer coefficient in the solar still. Therefore, these numbers have also been investigated for base fluid and Al2O3, TiO2, and CuO–water-based nanofluids in detail. Significant enhancement in natural convective heat transfer coefficient (Al2O3 67.03%; TiO2 63.56%; and CuO 71.23%) and Nusselt number (Al2O3 119.72%; TiO2 98.64%; CuO 151.62%) has been observed. The monthly productivity of the hybrid system found to be higher by using nanofluids (320.77 kg TiO2; 338.23 kg Al2O3, and 355.46 CuO) as expected from the heat transfer results. Moreover, the comparative study between the proposed hybrid system and passive DSSS has been carried out.

DETERMINATION OF THE CONVECTIVE HEAT TRANSFER COEFFICIENT OF HOT AIR RISING THROUGH TERRACOTTA FLUES

2012 ◽  
Vol 36 (4) ◽  
pp. 413-427 ◽  
Author(s):  
Taylor A. Oetelaar ◽  
Clifton R. Johnston
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Numerical Study ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Coefficients ◽  
Hot Air ◽  
Roman Baths

We experimentally studied natural convection processes inside terracotta flues as a part of a larger numerical study of ancient Roman baths. The air, heated in a plenum below the wall, rose through the tubes. Two clusters of thermocouples, equally spaced in the flues, measured temperatures throughout the thickness of the wall. The data from the two clusters proved to be measurably different. The resulting convective heat transfer coefficients determined using the bottom cluster, showed no dependence on the plenum temperature. The measured convective heat transfer coefficient was between 6.2 and 7.6 W/m2·°C, with an average of 7.0 W/m2·°C.

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