Experimental analysis of solar air collector with PCM-honeycomb combination under the natural convection

2019 ◽  
Vol 195 ◽  
pp. 299-308 ◽  
Author(s):  
Mesut Abuşka ◽  
Seyfi Şevik ◽  
Arif Kayapunar
2015 ◽  
Vol 789-790 ◽  
pp. 489-495 ◽  
Author(s):  
Daniel Marcelo ◽  
Paul Villar Yacila ◽  
Raúl La Madrid Olivares

In Peru, jaggery making process has low energy efficiency and it is due to low heat transfer coefficients for natural convection linked to the sugar cane movement generated by the heat exchange between the sugarcane juice and the combustion gases. This low heat transfer coefficients are caused by improper heat exchangers designs. In this work, is performed an experimental analysis that consist in supplie heat to a pot containing sugarcane juice using a hot plate of constant electrical power. This study consist in identify boiling regimes and estimate the heat transfer coefficients linked to natural convection boiling, measuring: (i) the temperature at the bottom of the pot (ii) the temperature at the bottom level of sugarcane juice (iii) the temperature at middle level of sugarcane juice (iv) the temperature at free surface of sugarcane juice (v) rate of water evaporated. The method of linear regression and the correlation of Rohsenow were used for obtaining the values of the heat transfer coefficients ranging from 4088.6 W/m2°C to 12592.8 W/m2°C with power input ranging from 700W to 1300W.


2015 ◽  
Author(s):  
Vilson Altair da Silva ◽  
Bruno de Campos Salles Anselmo ◽  
Ana Lúcia Fernandes de Lima E Silva ◽  
Sandro Metrevelle Marcondes Lima E Silva

2019 ◽  
Vol 13 (4) ◽  
pp. 30-40
Author(s):  
Saad Najeeb Shehab

       In this work, an experimental analysis is made to predict the thermal performance of the natural-convection phenomenon from a heated vertical externally finned-tube to surrounding air through an open-ended enclosure. Two different configurations of longitudinal rectangular fin namely, continuous and interrupted are utilized with constant thickness, different numbers, and different heights are extended radially on the outer surface of a heated tube. The tube is heated electrically from inner surface with five varied power input magnitudes. The effect of fins configuration, fins number, fins height, and heat flux of the inner tube surface on the thermal performance of natural convection have been studied and analyzed experimentally. Obtained results show that the tube with twelve interrupted longitudinal fins gives the best natural-convection thermal performance in terms of average Nusselt number, about 20% greater than that for the tube with continuous fins. Experimental correlations to predict the average Nusselt number for the heated tubes with continuous and interrupted longitudinal fins are proposed. The present data are compared to previous study and good convergence is noticed.


1988 ◽  
Vol 31 (1) ◽  
pp. 0293-0299 ◽  
Author(s):  
Arthur T. Johnson ◽  
G. Douglas Kirk ◽  
Soung H. Moon ◽  
Tien-Mo Shih

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