The subject of this master thesis is modernization of a system for steam production for the food industry. Since fossil fuels are becoming more and more unstable and insecure energy source, fossil fuel fired boilers are replaced by boilers using renewable energy source - biomass. The food industry is a large consumer of thermal energy with discontinuous processes. Such processes require large amounts of energy during short periods of time with sudden load changes. Biomass is the most important renewable source for producing thermal energy, but the standard biomass combustion systems can not respond to rapid load changes. To solve these problems, a techno-economic analysis of a proven technology (a cogeneration biomass combustion on a grid and steam turbine with controlled steam extraction) was performed. As an alternative, thermal oil boiler system, with a hot oil accumulator and a heat exchanger - evaporator for steam production is described in detail. A techno-economic analysis of this system was also performed for comparison with the cogeneration system. In the second part of the thesis, a mathematical model of the thermal oil system was created in Simulink-in order to show the system responses. The dynamics of individual parts of the system as well as the dynamics of the entire system were shown. In the end, a design and a layout of the hot oil accumulator were made.