The development of next-generation solar power plants requires high temperatures and high solar flux. Accurate simulations of strongly anisothermal turbulent flows are a scientific bottleneck for the development of these power plants. In this study, reference data obtained from Direct Numerical Simulations (DNS) is used to assess Thermal Large-Eddy Simulations (T-LES) of highly anisothermal turbulent flows. The simulations have a mean friction Reynolds number of around 800. We solve the low Mach number Navier-Stokes equations. In T-LES, the subgrid terms corresponding to momentum convection and energy equations are modeled with functional, structural, or mixed models. An extension of the AMD model to the compressible case is developed and different combinations of two-layer mixed models are tested. Different meshes and choices for the numerical scheme of the momentum convection are compared. The two-layer mixed models show the best results.