The minimization of fuel consumption in evaporation processes, could be achieved by using steam condensate heat recovery and also solar energy as a partial substitution for fossil fuels. In the presented article, the fuel savings methods in the one effect conventional and solarized processes are treated. The analysis includes the estimation of natural gas consumption, solar energy substitution and a summary of the savings for processes without and with condensate recovery. The reported results are obtained by calculations based on industrial plant data for NaNO3 evaporation and measured irradiation for a selected location in Croatia