• Energy Research

The study presents an investigation of thermal energy consumption for heating in an educational building located in the north-eastern part of Poland in 2017–2020, after deep thermomodernization. An evaluation of the actual energy effects was made based on measurements carried out over a 4-year operational period. They were compared with the results of theoretical calculations included in the energy audit and an attempt was made to describe the reasons for the discrepancies. The planned and achieved economic efficiency indicators were assessed and the amount of reduction of pollutant emissions was determined. The performed analysis allowed for an assessment of the impact of deep thermomodernization in terms of reducing heat energy consumption for central heating purposes, as well as reducing greenhouse gas emissions such as CO2, SOx, NOx and benzo(a)pyrene to the atmosphere. The implementation of thermomodernization in buildings led to savings of about 43% in terms of heat energy consumption for heating and a reduction in pollutant emissions. The theoretical savings based on the audit were 50.4%. The obtained results show that deep thermomodernization contributes to the improvement of energy and ecological efficiency in educational buildings, however, without the possibility of using subsidies, the investment is unprofitable. All the obtained results were discussed with the available literature sources and have been summarized with appropriate conclusions.

This work presents the results of a study that used a model based on rough set theory (RST) to assess the brine temperature of vertical ground heat exchangers (VGHEs) to feed heat pumps (HP). The purpose of this research was to replace costly brine temperature measurements with a more efficient approach. The object of this study was a public utility building located in Poland in a temperate continental climate. The building is equipped with a heating system using a brine–water HP installation with a total capacity of 234.4 kW, where the lower heat source consists of 52 vertical ground probes with a total length of 5200 m. The research was conducted during the heating season of 2018/2019. Based on the data, the heat energy production was determined, and the efficiency of the system was assessed. To predict the brine temperature from the lower heat source, a model based on RST was applied, which allows for the analysis of general, uncertain, and imprecise data. Weather data, such as air temperature, solar radiation intensity, degree days of the heating season, and thermal energy consumption in the building, were used for the analysis. The constructed model was tested on a test dataset. This model achieved good results with a Mean Absolute Percentage Error (MAPE) of 12.2%, a Coefficient of Variation Root Mean Square Error (CV RMSE) of 14.76%, a Mean Bias Error (MBE) of −1.3%, and an R-squared (R2) value of 0.98, indicating its usefulness in estimating brine temperature. These studies suggest that the described method can be useful in other buildings with HP systems and may contribute to improving the efficiency and safety of these systems.

Abstract The main aim of the thermomodernization of historic churches was to reduce energy consumption for heating and improve air quality by reducing the amount of pollutants emitted into the atmosphere. Calculation methodology was adopted in accordance with the Decree of the Minister of Infrastructure on the detailed scope and form of an energy audit [4] , [5] and based on the fuel indexes (WO) and CO2 emission (EC) for reporting under the Community Emissions Trading [13] . We have achieved a significant reduction of the annual heat demand and the reduction of emissions: SO2, NOx, CO2 and dust as a result of the modernization, with the exception of the Church in Chlopkow (No. 1). The results of the energy and environmental analysis show the validity of the religious buildings thermomodernization and upgrading their heat sources. These effects are necessarily connected with the economic effects. Practical application of this paper was to show the possibility of carrying out thermomodernization upgrades for reducing demand for heating, for thermal power and protecting the environment.

Abstract The aim of the installation of photovoltaic panels in the object of the Water Park was to use the possibility of supporting the production of electricity using solar energy. The article shows the adopted technological solution installation of photovoltaic and presents the results of the analysis of plant performance in real conditions, not just computational theory. The analysis of the installation work was performed on the basis of monitoring of operating parameters conducted in 2012–2013. The use of photovoltaic helped reduce CO2, SO2, NOx and dust emissions into the atmosphere on the value of installed power and reduce the amount of electricity drawn from the network (In Poland still based on coal and lignite). The results of energy and environmental analysis show the validity of installation of photovoltaic in objects like Water Parks. Energy and environmental effects combine necessarily the economic effects. It also helps to promote the local market to other forms of energy generation as well as improves the energy security of the Warmia and Mazury province, as well as part of the European Climate Change Programme (ECCP), which has lead to coordination of activities towards the reduction of greenhouse gas emissions.

Abstract An alternative to traditional solar collectors with absorbers made of metal or plastic can be panels which have their whole structure made of ceramics. The paper presents the results of the testing of ceramic solar collectors. The experimental research was carried out in summer 2016 in normal operating conditions. Rise in temperature of the fluid flowing through the collector was measured. The maximum value of this parameter did not exceed 7.5 °C and the maximum power output extracted from 1 m 2 of the ceramic solar collector under test was equal to 650 W/m 2 . The thermal characteristic of ceramic solar collectors was determined as the relationship between efficiency and the reduced temperature difference. The straight line corresponding to this characteristic is described by zero-loss collector efficiency coefficient equal to 0.8332 and heat loss coefficient equal to 16.332. Based on the analysis of the test results, it can be concluded that, in spite of some disadvantages, ceramic collectors can compete with traditional solar panels currently available on the market.

The paper presents an assessment of thermal energy consumption for heating in 10 buildings made in the OWT-67N prefabricated large-panel technology from 1983 to 1986. The work covers the years 2002–2020 in three periods: before and after thermal modernization and after the use of an innovative weather prediction heating system control in buildings. The analysis made it possible to assess the impact of carrying out a deep thermal modernization, and then installing a modern forecast regulation system in terms of reducing heat energy consumption for central heating purposes, as well as reducing greenhouse gas emissions, such as CO2, SOx, NOx, CO and benzo(a)pyrene, into the atmosphere. The implementation of deep thermal modernization in buildings allowed for savings of 19.8–35% of thermal energy consumption for heating. The use of additional regulation based on prediction saved from 4.8 to 23.5%, except for one building BU10, where there was an increase in final energy consumption by 2.1%. Replacing the weather regulation in heating stations with the forecast regulation additionally reduced the emission of pollutants by 11.1%, compared to the reduction of pollutants achieved as a result of the thermal modernization of buildings alone, amounting to an average of 29.7%.

Abstract The paper presents the results of the laboratory testing and numerical simulations of ceramic solar panels. The experimental research was carried out in artificial (laboratory) operating conditions. Rise in temperature and pressure drop of the fluid flowing through the collector was measured. As a result of the tests, the linear relationship between efficiency and reduced temperature difference was determined. While the pressure drop was approximated by the exponential function. Another research method based on numerical modelling using Computational Fluid Dynamics (CFD) algorithms was applied in this study. The three-dimensional geometric model of the ceramic panel was developed using the application included in the Ansys v. 19.2 package. The data obtained from computer simulations were compared with the results of the experiment to validate the numerical model. In order to find potential opportunities to increase the efficiency and due to the fact that the ceramic panel can be made in various inlet and outlet configurations, three simulation cases were considered: diagonal, top – bottom, and left – right. As the results of numerical calculations showed, the largest flow irregularity occurred in the last configuration. Based on the analysis of the test results, it can be concluded that, in spite of some disadvantages, ceramic panels can compete with traditional solar collectors currently available on the market.

This study evaluates a hybrid heating system in a single-family building in northeastern Poland, which has a temperate continental climate. The analysis covers two heating seasons in 2021/2022 and 2022/2023. The hybrid heating system includes an air heat pump HPA–08 CS Plus with a heating power of 8.2 kW (AHP), a condensing gas boiler VC146/5–5 with a power of 14 kW (GB–Condens.), and a solid fuel boiler with a power of 11 kW for central heating. Additionally, hot water is heated by a Basic 270 (DHW’s AHP) air–water heat pump with a power of 2 kW, utilizing a tank with a capacity of 270 dm3 equipped with two heating coils. The building’s average electricity consumption is around 5400 kWh/year. A 4.96 kWp photovoltaic installation is installed on the building’s roof at a 40° angle towards the south to supplement the hybrid system. The study aims to assess whether the PV installation can adequately cover the energy needs of the hybrid heat source for heating and hot water. Furthermore, the study calculates the emission of pollutants (CO2, SOx, NOx, CO, and PM10) into the atmosphere. The total annual electricity production from PV installations was 5444.9 kWh in 2021/2022 and 5684.8 kWh in 2022/2023. The excess electricity was stored in the PGE power grid as per the Prosumer settlement rules. The installed PV installation is sufficient to power the following devices annually: AHP, DHW’s AHP, and GB–Condens. However, the daily electricity production from the PV installation is not enough to cover the energy needs of the heat pump for heating during the cold months in Poland (I–III, XI–XII). It can meet the power needs of a PC all year round and can also be stored during the summer months, for example, in energy warehouses or by directly storing it in the PGE power grid. The use of the PV installation resulted in an average reduction in pollutant emissions into the atmosphere: CO2—94.1%, SOx—91.8%, NOx—95.6%, CO—9.7%, and PM10—32.1%.