New experimental investigation of the circumferential temperature uniformity for a PTC absorber

In this work, an experimental investigation of non-uniform circumferential temperature distribution (CTD) of a PTC absorber is done. Indeed, to evaluate the absorber CTD, a new method is reported by using real IR thermography profiles. The effects of focal length, absorber diameter, and outer glass cover (OGC) on the CTD are investigated. Moreover, a data visualization and statistical analysis are carried out. The most uniform and profitable flux distribution is found for a diameter of 0.042 m and a focal distance of 0.19 m. For this configuration, the highest eta(o) obtained in the cases with and without OGC is of about 57.16% and 60.87%, respectively. We notice that the temperature gradients and peaks increase gradually with the distance; a maximum temperature gap (Delta T-max) of 72 degrees C is reached for the distance of 0.26 m. In the case of OGC, the Delta T-max is only of about 63.6 degrees C (i.e., a difference of 8.4 degrees C). Thus, in the case of nonOGC, the highest mean and median temperatures of about 73.15 degrees C and 70.20 degrees C, respectively, are reported for a distance of 0.19 m. However, for the OGC case, the highest temperature values of about 80.8 degrees C and 76.8 degrees C, respectively, are reported for a distance of 0.22 m. In addition, the highest CTD uniformity is reported for a distance of 0.19 m, where an increase in the uniformity of about 2% is observed for the OGC use. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

An experimental investigation of non-uniform circumferential temperature distribution (CTD) of a PTC absorber was conducted, with a focus on the effects of focal length, absorber diameter, and outer glass cover (OGC). The most uniform and profitable flux distribution was found for a diameter of 0.042 m and a focal distance of 0.19 m. Additionally, the highest CTD uniformity was reported for a distance of 0.19 m, with an increase in uniformity observed for the use of OGC.