Novel non-concentrating solar collector for intermediate-temperature energy capture

Tremendous research efforts have been conducted studying the capturing and conversion of solar energy. Solar thermal power systems offer a compelling opportunity for renewable energy utilization with high efficiencies and excellent cost-effectiveness. The goal of this work was to design a non-concentrating collector, capable of reaching stagnation temperatures above 250°C and fluid outlet temperatures under flow above 200°C at 1000W/m2 solar irradiance. The study provides a detailed description of the methods and materials for construction of non-concentrating, high-temperature, evacuated solar collectors, the output fluid temperature depending on the input flow rate of working fluid in a low-flow rate, high-temperature regime, and an analytical description of the heat transfer between the collector and the working fluid. Temperature gains compared to ambient far above 200°C were possible under solar irradiance of 1000W/m2 with collector efficiencies of 30% and more. For a temperature gain of 227°C (fluid outlet temperature 253°C), the collector efficiency was 30%, and for a temperature gain of 214°C (fluid outlet temperature 240°C), the collector efficiency was 49%. This result opens up many new uses for non-concentrating solar collectors in fields such as power generation, fuel reforming, and catalysis. © 2014 Elsevier Ltd.

Duke Scholars

Author Nico Hotz Thomas Lord Department of Mechanical Engineering and Materia ...