International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Energy efficiency is an important part of the EU’s ambition to transition to a carbon-neutral economy by 2050. Greater energy efficiency will be needed in the future if the EU is to achieve this goal. All sectors of the economy have the potential to contribute to energy efficiency. Consistent energy management helps organisations realise untapped energy efficiency potential. In this way, they will benefit from cost savings and make a significant contribution to protecting the environment and climate by reducing harmful emissions and carbon footprints. This study aims to analyse the potential opportunities for businesses to realise savings, gain competitive advantages and achieve sustainable development and a positive image.

This paper investigates the inverse problem for thermal bridges – determining design parameters (such as material, geometry, thermal resistance R of the components) of the bridge at a known Psi-factor. By using artificial neural networks, a thermal bridge type IF (wall-floor connection) has been considered to evaluate the effectiveness of the methodology. The results show that the approach provides a fast and accurate way to predict the optimal parameters that meet specific energy efficiency requirements. In the future, this approach could help to determine the parameters of thermal bridges using thermographic images non-invasively.

There are many different models and types of heat exchangers depending on the area of use. The type of fluids involved in heat transfer and their temperature play a critical role in selecting the appropriate model. Common heat exchangers include plate exchangers, tube-type exchangers, air-cooled exchangers, and graphite exchangers. In this study, a sustainable and original heat exchanger system was designed to increase energy efficiency and reduce natural gas consumption by utilizing the waste heat from natural gas. The design prioritizes ease of maintenance and cleaning. Detailed engineering analyses were conducted, and critical engineering errors identified in previous heat exchanger designs were resolved. The developed designs were validated through test studies and experiments, leading to the final design after an optimization process.
As a result of the study, a high-capacity, energy-efficient, and sustainable heat exchanger integrated with modern technology was developed.

The publication examines the use of artificial neural networks to calculate the linear thermal conductivity (Psi-factor) of thermal bridges given various parameters, such as geometrical data and the thermal resistance R of the thermal bridge components. The neural network is trained on examples of IF, IW, and B thermal bridges, considering the straightforward task of determining Psi using given parameters. The neural network training results show high accuracy in calculations – RMSE is 1.132% on training data and 1.1423% on test data, and the correlation coefficient (R²) is around 0.9997 for both data sets. The applicability of the approach to seismic conditions in the Balkans is assessed.

One of the biggest challenges of our century is climate change. The aviation industry is a major contributor to global carbon emissions, and airports are responsible for a significant portion of this impact. To reduce the carbon footprint of airports, it is necessary to implement energy efficiency measures that can help reduce energy consumption and greenhouse gas emissions. This study analyzes the impact of the use of photovoltaic panels (PV) and the replacement of boiler burners with oil, on energy efficiency and the reduction of carbon emissions at the airport of Tirana. The electricity produced by these panels is used to power airport buildings, lighting systems and other infrastructure, reducing the need for traditional energy sources.
The reviewed period covers the year 2023, because during this year important investments were made with the installation of photovoltaic panels and the replacement of oil boiler burners with LPG burner, in addition to the improvement of the lighting system and the replacement of diesel vehicles with electric vehicles. Energy consumption data is used to calculate the carbon footprint and key energy performance indicators. The results showed that the use of photovoltaic panels and the change of burners of oil boilers brought a significant reduction of the carbon footprint and a significant economic benefit.

This study examines the impact of component materials on the energy performance of solar panels designed for water heating. For this purpose, we have integrated numerical simulations and experimental analyzes enabled by algorithms developed with LabVIEW software. The primary objective of this investigation is to assess how the selection of materials in the construction of solar panels affects their overall efficiency in harnessing and converting solar energy into heat for water heating purposes. The research methodology involves the development and implementation of advanced algorithms using LabVIEW, a versatile software platform known for its proficiency in data acquisition, analysis, and control. Numerical simulations focus on modeling the behavior of solar panels under different conditions, taking into account factors such as radiation, temperature and the specific characteristics of different component materials. These simulations provide valuable assessments of theoretical aspects of solar panel performance and enable the identification of optimal material combinations. Through the physical model, experimental studies are conducted to validate the simulated results. Physical prototypes of solar panel components are built using various materials and their performance is rigorously evaluated under real-world conditions. Experimental measurements allow data collection, and enable comparative analysis with numerical simulations. The results of this study aim to contribute to the advancement of solar panel technology by providing a deeper understanding of how material choices affect energy efficiency. Moreover, the use of LabVIEW software in the development of algorithms ensures a systematic and accurate analysis of numerical and experimental data.

The importance of artificial lighting in our daily lives is growing, and street lighting has become a major focus over time. The creation of street lighting was motivated by the need to increase visual and property security and public safety. Current developments in metropolitan environments foreshadow the ‘smart cities’ of the future. The basic concept is that CCTV cameras, traffic lights and street lighting all have ‘smart functions’. Municipalities will be able to adapt to the needs of their inhabitants, thus increasing safety, comfort and energy efficiency. Given the adaptability of smart street lighting to the built environment, artificial intelligence is an essential element of smart cities, even in the systems already in place. Extensive sensor networks will facilitate the collection of environmental data by AI. In addition, unauthorised access to information available through IoT systems poses a serious threat. A critical point is the monitoring and protection of surveillance systems that are vital to the operation of smart systems.

The application of old climate data in the design of buildings and transport infrastructure that will be used in the future is problematic because of climate change. On the other hand, it is currently unknown what the success of human actions to limit them will be. This leads to some uncertainty about the exact parameters of the climate until the year 2100. This requires a new approach to design and construction in the context of climate change. The article examines the impact of RCP (Representative Concentration Pathway) climate scenarios and regional climate models based on them, on design and construction for energy efficiency and sustainability. The significance of different RCP scenarios and the need for spatiotemporal scaling of climate data are discussed. The disadvantages of using a static representative climatic year (as it is in the Bulgarian regulatory documents for energy efficiency) are analyzed compared to its dynamic and adaptive variant.

Despite the efforts of the world community to limit global warming by reducing the greenhouse gas emissions emitted by societies, studies show that the levels continue to rise, and this hides a number of consequences for people’s lives. The European Union, with its 8% share of generated global emissions, is not among the leaders in emitting harmful greenhouse gases, but it is among the leaders in pursuing a systematic and strict policy of climate neutrality. A European Climate Act for a green transition was introduced in 2021, setting a binding target for EU countries of net zero greenhouse gas emissions by 2050, with an intermediate target of 55% by 2030 compared to 1990 levels. The purpose of this report is to follow the policy of the Union, the state and trends in the field of energy from renewable sources and energy efficiency and the participation of Bulgaria in the progress towards achieving the set goals.

Paper deals with a newly designed three-phase asynchronous electric motor with an application as a traction motor for driving compact battery-powered electric vehicles mainly in urban environments. The main characteristics of the motor are presented. The problems and solutions related to the sizing and optimization of the motor in the design according to various criteria and conditions are analyzed, with energy efficiency being the main determining factor.

Application of different retrofitting technologies can play a significant role in reducing energy consumption of existing buildings. This research work analyses a building in Cork (Ireland) where underfloor heating system, and natural ventilation are used to maintain comfort conditions. Underfloor heating system is the main electricity consumer of this building. Different energy efficient technologies were implemented and analyzed in terms of reducing electricity consumption through an energy software. These technologies include replacing illumination with high efficiency light; replacement of electric motos with high efficiency; introducing underfloor heating time scheduling turning on and off based on predicted weather condition; installation of presence sensors to switch ON/OFF lighting. Finally, it was decided to implement underfloor heating time scheduling as energy efficient technology to be analyzed because of limited budget available and high return on investments provided by applying this method. Result analysis shows that electricity saving on bills was about 20% on monthly basis compared to previous consumption.

With the developing food industry applications, the use of gastronorm containers is also increasing rapidly. It is widely used to transport, cook, preserve and serve gastronorm containers and food products. In line with international standards (EN 631-1, EN 631-2, etc.), the production process becomes more complex as the depth of gastronorm containers increases (from 20 mm to 200 mm / 6 different depths) and the process steps increase. Due to the errors arising from the process stages, there is an increase in the number of rejects, and thus energy efficiency is adversely affected. An automatic pressure balancing system design has been developed in accordance with the workflow in gastronorm container manufacturing with deep drawing technology. Providing the elimination of excess pressure steps and heat treatment needed in deep gastronorm containers (sizes and depths respectively: 1/2 200 mm, 1/3 150 mm, 1/3 200 mm, etc.), as well as the unique design of the integrated deburring machine, a significant innovation with industry 4.0 application has been imparted. Thus, in addition to the increase in product quality, it contributed to reducing unit costs by reducing high waste rates below 5%.