In the first part of my bachelor thesis I have been dealing with the composting process as such, I explained the different types of composting, the process of the composting and his individual phases. It was also important to clarify the importance of the components of compost composition. I have also described the principles of heat transfer and his collection from the composting process by using the hot water system. I have approached the reader with the current state of use of heat from the composting process in the world and with examples of possible solutions. The second part focuses on the design of the heat recovery system from the composting process itself. I have defined an object intended to heat and described the construction of a thermal reactor according to the pattern of Jean Paine. I also clarified how to calculate the reactor power and make a graphical design of the hot water system, which will heat up the necessary space and also record the temperature in it and in the compost itself.