Intensification of heat exchange in gas flues of solid fuel hot water boilers of low power

The introduction of a new flue design ensures a more complete use of thermal energy of fuel and reduces the negative impact on the environment. The main purpose of the study was to optimise the design of the behind-the-screen flue using plate guides for flue gases, which will reduce fuel consumption and increase the efficiency of the hot-water boiler. The results presented in the article were obtained using the following methods: generalisation of the results of previous studies, comparison, comprehensive analysis, elementary theoretical analysis and synthesis, experiment, logical and structural analysis, scientific and analytical analysis, etc. Modern measuring equipment, including a gas analyser, thermal imager, and pyrometers, was used in the experimental studies. The geometry of the behind-the-screen flue duct for Ukrainian-made hot-water boilers was studied and optimised in a wide range of capacities and gas flow rates. The obtained results made it possible to expand the possibilities of using boilers of this type and increasing their energy efficiency. A method of intensification of heat transfer processes and a method of improving the efficiency of the boiler by using a new design of an all-welded tube panel of the convective flue duct with cross-flow pipes with guide plates were proposed. The research extended the scientific knowledge of heat transfer processes in boilers with a shielded flue. The optimisation of the channel geometry and the use of refined theoretical models provide for a reduction in fuel consumption, reduction of harmful emissions and extension of equipment service life. The results of the study, obtained using computational methods and experimental measurements, were confirmed by comparison with the data of other authors and the results of field tests. A distinctive feature of the research is the high degree of agreement between theoretical calculations and experimental data and data given in the technical documentation for boilers. This indicates the reliability of the results obtained and the correctness of the research methods used. The article will be useful for designers, engineers, heat and power engineers and anyone interested in boiler technology