In recent years, extensive research has been dedicated to enhancing energy efficiency and promoting environmental sustainability in heating and cooling systems. Among the promising solutions, phase change materials (PCM) technology stands out as a key area of exploration. This study focuses on improving the thermal performance of PCM–water hybrid tanks by investigating methods to enhance thermal conductivity and heat transfer. Through experimental testing using techniques such as copper matrices, steel twisted matrices, and copper spirals, this study demonstrates significant improvements in thermal conductivity, particularly with the use of copper matrices. The integration of a copper matrix placed in the PCM reservoir increased the heat transfer coefficient and thermal conductivity of the PCM, and thus, the total phase transformation time for solidification was reduced by 79.19% and for melting by 54.7%. Our experimental results demonstrate that the integration of a copper matrix can increase latent heat transfer from 55,677.6 J up to 125,274.6 J, marking a 125% enhancement over the experiment with pure PCM. Additionally, comparisons of the energy storage potentials for different PCMs underscore the benefits of integrating PCMs into hybrid storage tanks. These findings highlight the immense potential of PCM technology to increase energy storage efficiency in heating and cooling applications.

To minimize the existing risks associated with the energy production, distribution, and development of urban areas, the concept of sustainable development of smart manufacturing is being introduced everywhere. However, most of existing digital transformation technologies do not sufficiently take into account environmental, economic, and social components. It requires the development of specialized solutions that, on the one hand, contribute to the development of the urban environment, and on the other, are focused on the use of innovative technologies that have a positive effect on the environment. However, in order to provide electric power to objects of a smart urban environment, we propose using autonomous power plants with renewable energy sources (wind and sun) instead of classical central power supply. The article describes the benefits of using combined wind-solar power plants to provide electricity to smart urban environments. The article considers advantages and disadvantages of this solution. We describe the design of the combined wind-solar installation with a vertical Darier rotor and photoelectric converters located on a common supporting structure. This solution allows getting a positive synergistic effect from the use of several renewable energy sources. The presented main advantages of this solution include increasing the energy efficiency of photovoltaic converters due to the intensification of heat removal from the surface of solar cells by the wind flow from the Darier rotor. In addition, this article considers the efficient use of the area and stability of electricity output. Digital aerodynamic modeling performed the parametric optimization of the Darier rotor having three blades with NACA 0021profile. The simulation demonstrated that the blades installed at an angle of 3.8° provide the maximum value of the wind utilization coefficient. This article also considers parametric optimization of a photovoltaic installation. In particular, the optimal installation angle of photovoltaic modules for Sevastopol is 34°.

Most low energy buildings only use electricity for heating, hot water preparation, and household appliances. This article presents the results of electricity measurements in a low-energy building. The article contains basic information regarding the buildings' technical equipment, design, and material solutions. Electricity consumption for hot water preparation, ventilation, and household appliances were taken into account for measurements. The effect of the solar panels on electricity consumption is also presented. Results show that electricity consumption is the highest in December and January. For the rest of year electricity is needed for household appliances only.

Thermal solar systems are currently one of the most suitable ways to convert solar radiation into usable energy. To ensure maximum energy gain, it is necessary to correctly adjust the direction of the collectors in the southern direction. The deviation from the south is energy acceptable, but there are losses that reduce the overall efficiency of the system. A suitable tool for increasing the efficiency of solar thermal collectors is the usage of tracker systems which track the position of the Sun along the ecliptic orbit. The system is directed south towards the equator. It is important to know the effectiveness of the system in terms of assessment. For the monitored period of the equinox, the increase of the solar thermal gain of the system with rotation of the collectors represents 16.23%. One of the methods is to use simulation tools to simulate different conditions of solar energy flow. A model in the Ansys software was developed for solar thermal flat collectors. The model is based on setting the material parameters of the collector construction, the properties of the absorber in terms of absorption as well as the materials and its geometry, the properties of the heat transfer medium, and the setting of the volume flows. At the same time, it is possible to define the change in the energy flow of the incident radiation. The model is a useful tool for evaluating collectors used by different tracking systems. The model was experimentally verified on a tracker system and compared with experimental data with good agreement. For sunny days, the model shows an accuracy rate of 98.7% in the condition without rotation, and 99.1% in the condition with rotation of the collector. After including the 5% degree of uncertainty for the condition of the rotated collectors, the accuracy of the model is 94.2% and for the condition without rotation 93.8%.

The paper focuses on the analysis of thermo technical interaction of frame and glass systems in a selected type of window construction, which is currently an important factor of building design that concerns cold and moderate climates. The analysis was based on the laboratory experiment in a climate chamber with a hot box for particular combinations of frame and glass systems (see the appendix). The results show that easily applicable modifications of window constructions could improve their thermal performance. Some potential for further improvement window constructions is also obvious