화학공학소재연구정보센터
Solar Energy, Vol.113, 189-198, 2015
Thermal analysis of a micro solar thermal collector designed for methanol reforming
A solar powered micro-reactor for hydrogen production is analysed in this study. A small, portable (similar to 4 W), compound parabolic concentrator (CPC)-based collector was designed and manufactured to provide heat for a methanol reforming (endothermic) chemical reaction. The designed collector consists of a small, flat, double-sided selective-surface receiver in a vacuum package. To our knowledge, the design represents the first time that a high vacuum package (<10(-2) Pa) has been combined with a CPC for this purpose. Our previous optical and thermal models predicted that 78% of incident solar flux could be concentrated to the flat receiver with a concentration ratio of 1.75. In this paper, the collector's performance was assessed for different volumetric flow rates (liquid flow rates at the inlet ranging from 0 to 350 mu L/min) with and without a vacuum to validate the theoretical analysis of our previous work. Results showed that the experimental temperature measurements without a vacuum were well matched with the theoretical values. Additionally, it was shown that the temperature can be dramatically increased in a vacuum environment. In the vacuum experimental configuration, a stagnation temperature of 327 degrees C was found for an irradiance of 1000 W/m(2). Temperature measurements for flow rates ranging from 0 to 100 mu L/min also agreed with the theoretical model. Overall, this system represents a compact, portable solar collector which is capable of achieving high operational temperatures without tracking. (C) 2015 Elsevier Ltd. All rights reserved.