Performance Analysis of a Metamaterial-Based Near-Field Thermophotovoltaic System Considering Cooling System Energy Consumption

Abstract

A mathematical physical model of a near-field thermophotovoltaic (TPV) system containing a metamaterial emitter comprised of W-nanowire arrays embedded in a SiC host is constructed. It is notable that this model incorporates a cooling system. On this basis, the influence of the emitter temperature and filling ratio, the cell and emitter thicknesses, and the emitter cell vacuum gap on the TPV system output performance is analyzed. It is found that the cooling device energy consumption increases by two orders of magnitude with decreased emitter cell gap size in the near-field; the highest possible value is 267.74 W·cm−2. However, the maximum net system efficiency is only 11.79 %. The emitter radiation capability can be enhanced by increasing the emitter temperature, but the cooling system energy consumption remains a significant problem. When the emitter temperature increases to 2200 K, the net system efficiency and net output density reach maximum values of only 6.22 % and 36.28 W·cm−2, respectively. Further investigation demonstrates that a large emitter thickness can induce a surface disturbance phenomenon, resulting in rapid decreases in the net system output power density and net system efficiency to − 251.85 W·cm−2 and − 12.86 %, respectively. However, when the cell thickness increases beyond 1000 nm, the net system efficiency and output power density are stable at 2.13 % and 24.12 W·cm−2, respectively. Finally, the emitter filling ratio should be increased as much as possible to maintain good system performance.