Front-surface cooling of infrared thermophotovoltaic cells

This paper proposes a front-surface cooling method for thermophotovoltaic (TPV) cells utilizing microfluidic channels for efficient heat dissipation. Unlike conventional back-surface cooling, front-surface cooling minimizes thermal resistance by directly cooling the top surface of the cell. The microfluidic channel layer also functions as an antireflection layer through the gradual change in the refractive index. The proposed cooling method was evaluated using a thermo-fluid analysis, considering factors such as the emitter temperature, cell reflectance, thermal resistance, and fluid optical properties. We examined liquids with ideal absorption characteristics and actual liquids whose absorption coefficients were measured. The results showed that front-surface cooling significantly outperformed back-surface cooling in terms of the net power density. This method is particularly advantageous for high emitter temperatures or in cases where the thermal resistance between the cell and back-surface liquid is high. Moreover, this study highlights the potential application of the cooling method in bifacial TPV cells, which can generate electricity from thermal radiation incident on both sides. Bifacial cells offer higher power generation per unit area but face cooling challenges. The proposed cooling technique addresses these challenges, paving the way for innovative TPV system configurations and improved performance.