Heat losses in Grätzel solar cells

The absorption and reflection spectra of a Grätzel-type solar cell were evaluated in terms of heat losses. Using these experimental data, the temperature distribution inside the solar cell was calculated. The temperature-controlling process in this cell is the heat transfer from the cell to the environment. Assuming the environment temperature of 25°C, the natural air convection leads to the temperature of 46.9°C inside the TiO₂ layer. Forced air convection causes the decrease, up to 30.1°C at the wind speed of 10 m s⁻¹. Variations in the cell dimensions, except the active layer length, have only a small effect on the temperature field, compared to the variations in the heat transfer coefficients.