Abstract: Large size (400mm diameter) CaF2 and BaF2 crystal ingots were grown successfully using our presented calculations based on experimental investigations of temperature fields and thermal exchange conditions in crystal growth furnaces. Our calculation approaches and their precision were confirmed experimentally. Presented results affirm usefulness of this approach to crystal growth and annealing problems solving for many new and for an improvement of existing systems. Calculating methods were extensively used to appraise boundary conditions in crystallizing containers of any complicated configuration and for successive temperature fields modeling for large size crystals at any stage of growth process. This is especially important, since up to the present time, there is no other, except calculated, methods to analyze thermal conditions in systems melt-crystal of alkali halide materials. Experimental results were successfully applied in growth equipment development using Stockbarger technique.