Performance, combustion characteristics and economics analysis of a combined thermoelectric and thermophotovoltaic power system

Abstract

Fast depleting reserves in conservative energy resources are principal motivation for developing highly efficient energy conversion systems. Thermoelectric and thermophotovoltaic devices are rapidly becoming promising solutions and they have revolutionized combustion-driven power generators. A combined thermoelectric and thermophotovoltaic power system was demonstrated experimentally and featured a gravity-fed fuel supply to attain stable combustion. Our aim was to better understand the influence of a fuel − air equivalence ratio on the performance and combustion characteristics of the combined system. The fuel − air equivalence ratio was varied for four types of fuel blends: 100% kerosene, 50%/50% vegetable cooking oil − kerosene, 80%/20% vegetable cooking oil − kerosene, and 95%/5% vegetable cooking oil − kerosene. The electrical power output varied almost linearly in a lean mixture of combustion. The peak values of the electrical power and efficiency skewed slightly rich of the stoichiometry, and these values decayed gradually in the rich mixtures. Detailed temperature profiles revealed efficient transfer of heat from the stabilized porous combustion to the input of both the thermoelectric and thermophotovoltaic cells. The carbon monoxide and nitrogen oxides emissions steeply increased beyond a stoichiometric value, and these emissions were marginally affected by the changes in the vegetable cooking oil contents. The concept appears to be attractive because the pertinent cost-performance analysis indicated a reasonably good similarity compared with other systems reported in the literature. Future advances in the combined power system can be realized by heightening key performance gains as well as effective cost-benefit strategies.