Estimation of heat loss from a cylindrical cavity receiver based on simultaneous energy and exergy analyses

Abstract

This study undertakes the experimental and theoretical investigation of heat losses from a cylindrical cavity receiver employed in a solar parabolic dish collector. Simultaneous energy and exergy equations are used for a thermal performance analysis of the system. The e ects of wind speed and its direction on convection loss has also been investigated. The e ects of operational parameters, such as heat transfer uid mass ow rate and wind speed, and structural parameters, such as receiver geometry and inclination, are investigated. The portion of radiative heat loss is less than 10%. An empirical and simpli ed correlation for estimating the dimensionless convective heat transfer coe cient in terms of the Re number and the average receiver wall temperature is proposed. This correlation is applicable for a wind speed range of 0.1 to 10 m/s. Moreover, the proposed correlation for Nu number is validated using experimental data obtained through the experiments carried out with a conical receiver with two aperture diameters. The coe cient of determination 2 and the normalized root mean square error (NRMSE) parameters were calculated, and the results show that there is a good agreement between predicted results and experimental data. 2 is greater than 0.95 and the NRMSE parameters is less than 0.06 in this analysis.

Modeling, testing, and parametric analysis of a parabolic solar cooking system with heat storage for indoor cooking

“…18 shows that increasing the fluid flow rate from 0 to 18 kg h −1 increases the storage temperature by 65°C, and beyond this value, there is no significant improvement of the system performance. These results are very similar to those found by Rongrong et al [8], Luo et al [14], and Madadi et al [20]. The outlet oil temperature in the receiver will be reduced when increasing flow rate in the same working condition.…”

“…Madadi et al [20] used many receivers which have an aspect ratio of 2, 2.8, and 3.6 and show that the effect of receiver temperature on radiation loss for greater apertures is higher than smaller apertures. The radiation heat losses from the receiver in comparison with convection heat losses are so low.…”