This paper is focused on the research of gravitational heat pipes for heat recovery for hot water heating from the flue gas in small biomass heat sources. The paper includes a proposal of an experimental device, with the help that is explored the influence of the amount of water filling at various temperature parameters (heating temperature and temperature cooling) on transferred heat performance by gravitational heat pipe. There is also introduced in a measuring procedure for heat pipe by using the proposed experimental device and measurement results. Due to the similarity of the experimental measurements with the prototype for heating of hot water in small combustion heat sources, the heating of heat pipe is made by hot air and the cooling on the condenser section of heat pipe is carried out with water. At the end of the article is an analysis of the obtained results which are compared to the numerical model. Based on the results obtained from experimental measurements would be possible to design a prototype of water heater, which uses a gravity heat pipe for heat transport. The heat pipe would safely heat the water in a storage tank by flue gas in the flue gas duct of the small heat sources using biomass fuel.

The article describes the measurement methods and data evaluation from a single-stage axial turbine with high reaction (50%). Four operating modes of the turbine were selected, in which the wake traversing behind nozzle and bucket with five-hole pneumatic probes took place. The article further focuses on the evaluation of bucket losses for all four measured operating modes, including the analysis of measurement uncertainties.

This article is focused on the research of passive cooling beams and increasing their cooling capacity. A passive cooling beam with four tubes was chosen as a model. A mathematical model was built using the corresponding criterion equations to capture the behavior of a passive cooling beam. This mathematical model can be used to optimize geometrical parameters (the distance between the ribs, rib height and thickness, and diameter and number of tubes), by changing these geometric parameters we can increase the cooling performance. The work includes a mathematical model for calculating the boundary layer, which has a significant influence on the cooling performance. The results obtained from the created mathematical model show that the model works correctly and can be used to optimize the cooling performance of passive cooling beams. To better understand the behavior of a passive cooling beam in a confined space, the entire device was numerically simulated, as was the flow in the intercostal space.

At present there is a tendency to make greater use for heating houses for burning solid fuel, such as pieces of wood, coal, coke, local sources of heat to burn natural gas. This tendency is given both the high price of natural gas as well as the availability of cheaper solid fuel. In many cases, in the context saving heating costs, respectively in the context of the disposal of waste is co-incinerated with municipal solid fuels and wastes of different composition. This co entails increased production emissions such as CO (carbon monoxide), NOx (nitrogen oxides), particulate matter (particulate matter), PM10, HCl (hydrogen chloride), PCDD/F (polychlorinated dibenzodioxins and dibenzofurans), PCBs (polychlorinated biphenyls) and others. The experiment was focused on the emission factors from the combustion of fossil fuels in combination with municipal waste in conventional boilers designed to burn solid fuel.

The production of solid pollutants is affected by several influences. The amount of combustion air and its redistribution to primary and secondary combustion air. The experimental device, what which has been examined the amount of the combustion air on the production of the solid pollutants, methods of measurement, measurements results and analysis of the results obtained will be described in the papers.

EPJ Web of Conferences, open-access proceedings in physics and related sciences