The theme of the article is to determine the possibility of waste heat recovery and use it to prepare hot water. The scope includes a description of the existing sample of coal-fired boiler plant, the analysis of working condition and heat recovery proposals. For this purpose, a series of calculations necessary to identify the energy effect of exhaust temperature decreasing and transferring recovery heat to hot water processing. Heat recover solutions from the exhaust gases channel between boiler and chimney section were proposed. Estimation for the cost-effectiveness of such a solution was made. All calculations and analysis were performed for typical Polish conditions, for coal-fired boiler plant. Typicality of this solution is manifested by the volatility of the load during the year, due to distribution of heat for heating and hot water, determining the load variation during the day. Analysed system of three boilers in case of load variation allows to operational flexibility and adaptation of the boilers load to the current heat demand. This adaptation requires changes in the operating conditions of boilers and in particular assurance of properly conditions for the combustion of fuel. These conditions have an impact on the existing thermal loss and the overall efficiency of the boiler plant. On the boiler plant efficiency affects particularly exhaust gas temperature and the excess air factor. Increasing the efficiency of boilers plant is possible to reach by following actions: limiting the excess air factor in coal combustion process in boilers and using an additional heat exchanger in the exhaust gas channel outside of boilers (economizer) intended to preheat the hot water.

Straw is treated as agricultural waste, and it is available in almost every region of Poland. A total of 30 million tons of straw is produced per year, of which there is a surplus of approximately 13.5 million tons of undeveloped straw. For energy purposes, straw from cereals or rapeseed is most often used. When analyzing scientific publications, it was noticed that, in Poland, large amounts of oat straw are produced, and there is no alternative use for it. Hence, we conducted research to determine the energy value of oat straw. Raw material was obtained from an individual farm from 2018 to 2020. Selected energy parameters for straw burned alone (100%) or co-fired with coal were analyzed in the following weight proportions: 70/30, 80/20, and 90/10 coal/oat straw. It was shown that changing weather conditions, in particular years, had a modifying effect on some of the energy parameters of straw. The calorific value of straw was lower than that of coal, but its impact on environmental pollution turned out to be significantly lower. The difference in combustion heat between coal and straw was 11.74 MJ·kg⁻¹. Investigations into pollutant concentrations were performed for cubes of compressed straw and hard coal. Mixtures of these fuels were not studied in this part of the work. The combustion of straw resulted in a reduction of harmful NO, NO_X, and SO₂ pollutants and an increase in CO compared to coal combustion. As for hydrogen content—it was the highest in carbon and the lowest in straw. In the case of analytical moisture, an inverse relationship was observed. In the case of both coal and straw, the ash content varied throughout the years of research. As the boiler power increased from 5 to 25 kW, the consumption of burned raw material increased significantly. The results indicate that the surplus of oat straw can be rationally used to obtain thermal energy, including co-combustion with coal. This will allow one to avoid burning straw in the fields, which causes great harm to the natural environment.

By low emission, we mean the pollution of the lower troposphere from emitters not exceeding 50 m in height and most often located at a level of 10 m in height. Due to such emitters the altitude this pollution accumulates around is its place of emission. The basic source of low emissions in Poland are pollutants caused by vehicular traffic and during the process of burning low quality coal, and rubbish - in domestic furnaces. The reason is the lack of proper filtrtation in these devices. Most air pollutants are gaseous substances. The second group is dust. Contamination is different in physical and chemical terms. The most dangerous for people and the environment are: dioxins, polycyclic aromatic hydrocarbons (benzopyrene), carbon monoxide, sulfur dioxide, nitrogen oxides, heavy metals (eg cadmium, manganese, chromium), and hydrogen cyanide. The largest increase in suspended particulates during the heating season affects a majority of single-family housing estates, due to the lack of system heat. It is a fact that many users have antiquated coal furnaces in which low-quality coal and sometimes waste is burned, for example, colored press, rubber, plastics, and impregnated wood. Unfavorable weather conditions during the heating season intensify this phenomenon which is known as smog. This publication is aimed at presenting methods for reducing the emission of pollutants into the air due to the combustion of inadequate fuel in areas of low residential buildings. The solutions, based on the replacement of fifth-generation furnaces as well as a change of fuel, have been proposed.

In October 2014 in a building of Rzeszow University of Technology, a series of measurements was taken to calculate the parameters of a solar system with a flat collector, as installed on the roof of the building. The following parameters were obtained: the value of solar radiation intensity, the...

A lot of attention is nowadays devoted to the problem of generally defined ecology. It is absolutely essential in case of systems and sources generating heat due to their direct influence on the environment through emitting post-process products to the atmosphere which are, most frequently a...

Nowadays, much attention is paid to the elimination of heat sources poisoning our environment. Air pollution is the most dangerous form of pollution of the environment due to its direct impact on all living organisms, coverage of large areas and easy movement of pollutants. Therefore, air...