The carbon dioxide emissions, caused by humans, are rising from year to year to new record levels, as seen from the world climate report 2014 from IPCC. According to the experts of the UN climate report there is still hope, but the carbon dioxide emissions have to be reduced. In this case, the hydrothermal carbonization could make a contribution. The HTC is a thermo chemically and exothermic process which converts solid biomass at higher temperatures (180 - 220 C) and higher pressures (10 - 25 bar) in the presence of water. The products are brown-coal-like HTC-coal, process-water and HTC-gas. The process of the hydrothermal carbonization was rediscovered at the beginning of this century, so it is still the phase of basic research and the development of an continuous process. The series of experiments was conducted in a discontinuous reactor (batch reactor). This reactor has an internal volume of 1,7 liters. In this thesis, several improvements were implemented on the reactor. A pressure sensor and a temperature sensor was fixed on the reactor and connected with a microcontroller. So the automatic record of the process parameters was possible. Additionally the temperature signal of the heating jacket was installed inside of the reactor, thereby providing better control of the heating is possible. In addition to the temperature and the pressure also the energy input was recorded. A total of 33 experiments were carried out with different biomasses (fir needles, pistachio shells, digested sludge, corn straw, MIX and algae). The biggest part of the experiments was realized by 180 C and in 6 or 12 hours. To determine the heat of reaction, a new method was developed. Also a mass balance was established, an elemental analysis of the input-materials and the HTC-coals was carried out and the loss on ignition was determined. On average 11,2 MJ/kg TS were obtained for the heat of reaction, this magnitude could be found also in literature. When considering the increase in energy density, based on the organic dry matter, all input-materials, except algae, could increase their content of carbon by 6 - 11 % oTS and their heating value by 4000 - 5500 kJ/kg oTS. In this thesis the hydrothermal carbonization could be verified. But further research is still essential, especially the process-water and the HTC-gas should be examined more closely. In addition, an approach should be developed for a continuous process.