FEASIBILITY OF HYBRID THERMOPHOTOVOLTAIC AND REFORMER/FUEL CELL ENERGY CONVERSION SYSTEMS

摘要

This work examines the performance of hybrid energy conversion systems that combine thermophotovoltaic (TPV) technology and fossil fuel or bio-fuel reforming methods. The result is a novel approach for the extraction of hydrogen gas from existing energy vectors with the added benefit of electricity production. TPV systems produce electricity from a high temperature source of thermal radiation by using a semiconductor pn-junction similar in operation to solar cells. While most commercially available TPV systems combust a fossil fuel for the energy source, some systems use waste heat from another process. One scenario involves a system whose first stage uses TPV cells to extract electrical energy from a high temperature emitter powered by the combustion of fuel. This is followed by a second stage that utilizes the waste heat from the TPV process to power the fuel reforming stage. Another scenario involves the normal operation of a reformer or high temperature fuel cell that is surrounded by an array of TPV cells to produce electricity This analysis involves a system whose first stage uses TPV cells to extract electrical energy from a high temperature emitter powered by the combustion of fuel. This is followed by a second stage that utilizes the waste heat from the TPV process to power the fuel reforming stage. The hydrogen can then be stored or consumed in a fuel cell system. In this scenario, the electrical energy from the TPV can contribute to the balance of plant (BOP) requirements of the reformer and/or fuel cell. The remaining heat energy can be re-circulated to increase plant efficiency or used in a direct heating application. The TPV system will act as another load on the incoming fuel, but depending economic factors or the application being served, a different mix of hydrogen, electricity, and waste heat may be more efficiently delivered. The coupling of TPV and fuel reformation offers another path to bridging the hydrogen supply gap that exists by using current energy vectors to obtain hydrogen gas while minimizing energy conversion losses. To truly access the validity of the hybrid TPV/MSR a fully integrated proof-of-concept prototype is required. This prototype would lead to empirical data that could be used to scale the technology to efficient large-scale applications of TPV/MSR systems.