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This paper deals with the issue of air cooling in outdoor areas of human habitation. An analysis of air parameters during the summer season was carried out to determine the thermal comfort zone for a part of the northern platform of the local station in Rzeszow (Poland). The cooling capacity required for thermal comfort was calculated using outdoor air parameters and heat gains in the vicinity of the research object. Ten potential air-cooling systems were proposed for the outdoor zones. The systems differed in terms of cooling equipment, primary energy source, cooling medium, and recipients. They were divided into three categories: compressor, adsorption, and evaporative cooling. The electricity yield of the existing photovoltaic installation at the research facility was evaluated to identify potential synergies between the cooling demand and solar energy. An analysis assessed the energy, economic, and environmental impact of each proposed option. The best option for cooling the outdoor areas was found to be an evaporative cooling system with a PV system. Solar radiation can be effectively used for cooling outdoor zones in Poland in the summer. The optimal solution for the research facility is an evaporative cooling system based on direct evaporation combined with a photovoltaic system. The subject matter covered can be used as an effective tool for the optimal selection of outdoor air-cooling systems to ensure the thermal comfort of the occupants. [ABSTRACT FROM AUTHOR]

In this paper results of influence of building-installation system parameters on value of energetic coefficients were calculated. Three types of buildings (standard, energy saving and low energy) with heating surface of 100, 150 i 200 m2 were used. The above types of buildings differ on thermal barrier and heating system efficiency. The influence of the gravity and mechanical ventilation systems on the final heat energy of different kinds of houses was shown. Parameters of the certificate for energy characteristics of building were used. Mathematics models of influence of thermal barrier parameters and heating surface on the value of energy characteristics, namely final energy EF, primary energy EP and useful energy EU were established. Influence of such parameters as heating energy factors, ventilation system and energy sources on the energy efficiency improvement of buildings was analyzed. The building environmental assessment system was proposed on the base of energetic and ecological analysis of houses.

The aim of this article was to determine the energetic effect of adapting the control method of district heating substation to a solution using dispersed heat storage. The current control method of district heating substation uses the equations for regulating the temperature distribution of the installation water based on the value of the external temperature. This control method causes a significant amount of heat not consumed by end users. To adapt the control method to a solution using dispersed heat storage the following values were analyzed: the forecast of external temperature and duration of episodes with the lowest external temperatures on the heat output of the district heating substation based on 63 heating seasons. Obtained results were presented for a district heating substation in Poland. The analysis shows that a temperature of -15°C can be adopted as the reference to determine the expected heat output of the district heating substation. On this basis the demand for heat output for central heating purposes was 406 kW instead of 430 kW. The energetic effect of use dispersed heat storage to compensate the reduced heat output of the district heating substation was 24 kW with a compensation time of 24.2 h.

The main goal of this investigation was to increase the solar fraction and reduce the demand for non-renewable primary energy in a building heating system. Thermal performance of the prototype evacuated tube solar collector/storage integrated with a PCM (ETC/PCM) was analyzed. Technical grade paraffin with onset melting point of 51.24°C was used as a PCM. It has been shown that the highest solar energy fraction in the building heating system was obtained with a thermal load of 40 W·m-2 and the highest the surface area of ETC/PCM aperture in relation to the heating surface area value of 0.2. Lowering the heating system parameters from 45/35°C to 35/25°C allowed for an increase in heat output from solar energy in the range from 2.71% to 5.44%. The largest increase in the solar fraction was in the range of the ratio of the surface area of the solar collector ETC/PCM aperture to the area of the heated building from 0.03 to 0.07. In summary, obtained results indicated that the proposed solution allowed reduction of non-renewable primary energy demand in conceptual heating system from 6% to 27% depending on the heat load of the building and the aperture area of the ETC/PCM.

The article presents the assessment of the environmental impact of 9 variants of building heat supply for heating purposes. The building energy standards and the main primary energy carriers being in use in Poland were taken as input data. The subject of analysis was a single-family house characterized by a utility energy demand of 47 kWh/(m2 year). An environmental impact analysis was made using the specification for LCA in damage categories encompassing human health, ecosystem quality and natural resources depletion. From the obtained results it has been found that coal-based technologies in Poland's building energy supply systems are capable of reducing the noxious environmental impact. An example of such a system is the effective heat distribution network with a coal-based cogeneration energy source. From the point of view of radical low emission reduction, an interesting solution is the effective heat distribution network with a gas-based cogeneration energy source. Nevertheless, forecasts about the development of renewable energy source installations in Poland indicate that a significant role in building heat supply systems will be played by solar systems and geothermal systems using heat pumps. Achieving the environmental acceptance of heat pumps in Poland's conditions requires a decisive intensification of efforts to increase the share of renewable energy sources in electric energy generation processes in the central electric power system and in local and individual systems, as well as the continuation of the processes of thermal insulation of already existing buildings.

Meteorological analyzes unambiguously indicate climate warming. An increase in average air temperatures is recorded in both winter and summer. In recent years, an increasing number of hot and very hot days are observed, and the duration of series of days with maximum daily temperature above 30°C is also longer. Occurrence of hot weather adversely affects the person staying outside. The ever-increasing requirements related to thermal comfort, enforce the provision of appropriate conditions not only in the rooms, but also in the external zones of people. Cooling the air in outdoor zones using standard air-conditioning systems can be expensive due to the high demand for electricity. Ensuring cooling through the use of renewable energy, such as solar energy, is a key solution to energy and environmental problems. In this article, the technical potential of solar radiation energy was determined based on data from the Rzeszow- Jasionka meteorological station and the possibilities of using solar energy in air cooling systems in external zones were presented.

On the thermal comfort of a man staying outdoor during the summer affect mostly meteorological factors, physical activity and the type of clothing. The work analyzed external air parameters, such as: temperature, relative humidity and wind speed, occuring in years 1997‒2016. Meteorological data recorded at the RzeszÓw-Jasionka station allowed to determine, among others, the occurrence of maximum daily and hourly temperatures of outdoor, the daytime and hourly air relative humidity, the hourly wind speed, as well as the relationship between these parameters. In recent years, it has been observed the increase of the number of hot and very hot days which indicates a warming of the climate. The duration of series of days with maximum daily temperature above 30°C is also prolonged, which is not comfortable for a person staying outside. During summer, during hot and very hot days, the average relative humidity remained below 70%. The daily course of this factor was characterized by the opposite tendency with respect to temperature. The wind speed in the summer season varies from 0 to 6 m/s. On a daily basis, the increase in wind speed occurred in the afternoon hours which is consistent with the temperature characteristics. The occurrence of wind during the hottest hours causes a pleasant cooling of the organism.

The main objective of the article is to indicate the directions of development of new generations of supplying buildings with heat, by using phase change materials, referring to the technical possibilities of applying available heat storage technologies. As a detailed objective of the work, the determination of the impact of using a PCM accumulator on the temperature of the heat carrier on the return in the substation of the district heating system was adopted. Range work included determination of parameters of heat distribution network as a function of outdoor air temperature range of -20°C to +12°C. As the analysis object, the heat substation has been selected with the following parameters: supply 80°C and return 60°C. It was found that thanks to the use of PCM accumulators on heat substations, it is possible to save energy by up to approx. 6.7% and achieve economic benefits in the form of a payback period of approx. 13 years. In addition, it was found that the introduction of the PCM accumulator into the heating system allows the return temperature in the heating network to be obtained at a temperature level consistent with the adopted control table for external temperatures of the standard heating season.

The paper presents a new method of determining the thermal power demand of buildings connected to the district heating system, which included the actual heat demand and the possibility of balancing the thermal power using the thermal storage capacity of district heating network and internal heat capacity of buildings. Moreover, the analysis of the effect of incidence of external air temperature and duration of episodes with the lowest outdoor temperatures on the thermal power demand of district heating system was conducted.

The main objective of this article is to indicate the direction of development of new generation heating systems that use phase change materials, and the important criteria needed when choosing a phase change material. The work contains a detailed classification of materials using the latent heat of organic and inorganic PCM. This references the technical possibilities of existing heat storage technologies. A specific objective was adopted to determine the effect of using heat storage with PCM on inlet and outlet temperatures in substation in district heating systems. The scope of the study included determining the parameters of the heat distribution network as a function of an outdoor air temperature within the range of -20°C to + 12°C. The object of analysis was chosen to be the heating system parameters: supply 120°C and return 60°C. It is located on the surface of 160km2, and supplies heat to 240,000 residents. The total length of the district heating network is 170 km. Based on the study, it was found that the most advantageous material that accumulates heat depends on the return temperature in the heating network. For the above analyzed case, the return temperature was in the range of 46°C to 57°C. The analysis showed that the most preferred materials using heat of phase change, have possible applications in heating networks and received a return temperature including salt hydrates, such as MgSO4·7H2O and Na2S2O3·5H2. The introduction of stored heat for the district heating system with the phase change material in the form of salt hydrates, allows the return temperature in the district heating to remain at temperatures compatible with the adopted regulatory table for temperatures outside the standard heating season.

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The article presents the results of operational, numerical and experimental studies on windbox operating in a 235 MWe-power fluidized-bed boiler. The main problems of windbox design have been identified in the context of the problem of loose material backflow into the windbox space. [ABSTRACT FROM AUTHOR]

An analysis of the effect of thermal and flow conditions in the combustion chamber of the circulating fluidized-bed (CFB) boiler on the gaseous pollutant emission was undertaken in the study. The tests were carried out on a 670 MW boiler operating in the power engineering industry. On the basis of the obtained test results it was found that the optimization of primary and secondary air distribution, as well as fuel distribution, allowed the following pollutant reductions: CO by 52%, SO2 by 40% and NO by 6% in relation to the standard operation conditions of the boiler under investigation. The test results demonstrated that increasing the number of repetitions of bed material particle circulation between the combustion chamber and the recycling system resulted in an equalization of temperature distribution along the combustion chamber height and elongated the time of residence of sorbent particles in the CFB system. Ultimately, the test results showed the following pollutant reductions: CO by 71%, SO2 by 41%, and NOx by 19% with the number of particle circulation repetitions increased from 28 to 60 for the boiler analyzed. [ABSTRACT FROM AUTHOR]

Abstract: The results of numerical computations for 670t/h CFB boiler are shown in this paper. The calculations have been carried out for two different so-called oxyfuel conditions, i.e. when combustion runs in a gas mixture based on O2 and N2, and another, when combustion takes place in N2-free atmosphere of O2–CO2, with various fraction of oxygen in both cases. Compared to conventional air-combustion, two crucial differences were taken into consideration in this paper: reduced volume of flue gas for oxygen-enriched environments and changed heat duty inside combustion chamber following from an increase in adiabatic temperature. [Copyright &y& Elsevier]