A potential heat source for the micro-thermophotovoltaic (TPV) system

Abstract

The micro-combustor (emitter) is a key component of the micro-thermophotovoltaic (TPV) system. Compared to the cylindrical tubes, an advantage represented by a planar channel is the radiation flux normal to the PV cell. Gaseous premixed combustion of H2-air in two planar micro-combustors with the channel widths of 1 and 1.5 mm, respectively, were experimentally studied. Based on the results of the pre-experiment on ignition, two configurations were chosen for wall temperature measurement-'with mesh (at the combustor inlet)' and 'with porous media (at the middle of the combustor), with mesh (at the combustor inlet)'. The wall temperature was measured by an IR thermometer under the flow conditions of Φ=0.6-1.0 and U0=2-3 m/s. The experimental results showed that increasing the flow velocity results in higher wall temperature. Under the same flow conditions (U0 and Φ), the larger combustor (H=1.5 mm) gives higher wall temperature than the smaller one (H=1 mm). In addition, the inclusion of the porous media leads to an increase (∼100 °C) of peak wall temperature, compared to the case 'with mesh'. The emitter efficiency was quantified based on the measured wall temperature. It was noted that the highest efficiency is achieved at Φ≈0.8, regardless of the channel width, flow velocity and specific configuration. Besides, the emitter efficiency is greatly improved with the inclusion of the porous media, representing an advantage of the configuration as a potential heat source for the micro-TPV system. The results presented in this paper demonstrate that porous media combustion offers another means by which self-sustained combustion of the gaseous mixture in the micro-combustors can be achieved. Future studies were also recommended. © 2009 Elsevier Ltd. All rights reserved.