This bachelor thesis deals with the principle of the operation of gasification boilers which have small capacity (up to 500 kW) and which have manual fuel supply. The first part of the thesis consists of the literature review and describes the basic distribution of the boilers according to the type of fuel used and according to the basic principle of their operation. The gasification boilers are described in more detail in this part of the bachelor thesis. The second part of the thesis includes a description of the emission measurements which were performed on a selected test boiler (Damat Pyro 20 G) and the evaluation of the results of these measurements. The measurements were conducted in accordance with the ČSN EN 303-5 according to whic...