• Energy Research

Nowadays, as the technology behind solar photovoltaic systems has been significantly improved, along with a significant decrease in costs, grid-connected photovoltaic systems are becoming an important option to reach a low-carbon energy transition. The high cost of electricity consumed at the Technical University of Cluj-Napoca represented a good reason for the university to increase its energy efficiency by adopting and increasing energy consumption from renewable energy sources. This paper assesses the technical, economic, and environmental feasibility of deploying four photovoltaic systems at the aforementioned university situated in the Northwestern part of Romania, according to the Romanian renewable energy legislation. PVSOL software has been used to estimate the performance of photovoltaic installations. The results indicated that the most viable distributed generation system is the one with a capacity of 100 kW, meeting approximately 23 percent of university electricity needs, and at the same time, reducing carbon dioxide emissions by approximately 460 tons. A sensitivity analysis has been performed to evaluate the effect of several critical parameters on the PV system’s economic feasibility. The results provide valuable decision-making information regarding the buildings’ solar potential for other universities, supporting the transition to solar energy.

The importance of archaeometric investigations, performed with technical support is not only that eases the work of archaeologists, but also contributes to optimize human, financial and time resources. Thus the study highlights the results of investigation of an archaeological site from the imperial roman era through a method specific to electrical engineering. Accordingly, based on some soil resistivity measurements made in the Legionary Camp of Potaissa - fortress where the 5th Macedonian Legion camped, members of the Archaeometry Laboratory from the Technical University of Cluj-Napoca were able to identify and establish the trajectory of buried walls that were marking the specific construction of the barracks belonging to the troops in Cohors I Miliaria. In order to perform this task, a genetic algorithm based technique was used to determine the different soil layers.

This research explores the impact of the COVID-19 pandemic on consumer behavior and preferences related to household energy consumption through actions to fight climate change in Belgium, Romania, Italy, and Sweden. Using data from two Eurobarometer surveys conducted in 2019 and 2021, the study examines shifts in climate change perception, actions to combat climate change, and the influence of socio-economic and demographic variables on these actions. Depending on the country, the findings reveal significant pandemic-induced changes in public perceptions of climate change and personal actions to combat it. Age, gender, and education level were found to influence climate change actions. Financial constraints also significantly influenced the adoption of energy-efficient behaviors. Our research enriches existing knowledge by exploring the influence of the COVID-19 pandemic on climate change perceptions and actions across diverse European countries, shedding light on the interplay between global crises and sustainability. The research methodology, including chi-square tests, logistic regression, and effect size measurements, provides a robust framework for understanding how economic factors and consumer behaviors are contributing to the development of effective energy policies.

The paper studies the electromagnetic interference between an existing high voltage power line and a new designed stream gas pipeline intended to be placed in the same distribution corridor. A companion paper has investigated soil resistivity along the common right-of-way. Based on the obtained horizontally and vertically layered equivalent soil models, in this paper, a detailed analysis of the induced AC interferences in the underground pipeline is done, for different normal and fault operating conditions. Two different software packages were used to evaluate the induced voltage and current levels: CDEGS and InterfStud (developed by the authors). Obtained result has been compared to each other and to European Standard Regulations.

This paper presents the initial steps taken in analysing the benefits of connected autonomous vehicles (CAVs), especially Modular Autonomous Vehicles (MAVs), in search of sustainable solutions for reducing energy consumption per passenger in air transport. For this particular case, a Mobility-as-a-Service (MaaS) solution is proposed, correlating airside transport with landside transport, as an urban mobility alternative. To better understand the benefits of the proposal, this paper studies the impact on energy consumption conceptual differences between a conventional public transport fleet using Battery Electric Buses (BEBs) and an MAV fleet. Simulations for simple public transport tasks are performed to highlight the advantages of the modular vehicle concept, in which routes are assigned dynamically based on the requested passenger carrying capacity and travel distance, aiming to optimize the efficiency of the entire system. With a proven reduction in energy consumption due to better use of available passenger capacity and reduced travel times in which the vehicle is driving with a number of passengers less than half of its capacity, the concept can be addressed further in developing a predictive system that processes public transport data and delivers an optimized schedule for the entire fleet. The main goal being to improve overall operational efficiency and total cost of ownership, the second part of the paper studies the impact of weight distribution on efficiency parameters such as energy consumption, range, and overall performance of an electric bus. The impact on dynamic elements such as acceleration, braking, and cornering performance is analyzed, to assess the viability and safety of all types of electric bus operations.

Short-term electricity load forecasting has attracted considerable attention as a result of the crucial role that it plays in power systems and electricity markets. This paper presents a novel hybrid forecasting method that combines an autoregressive model with Gaussian process regression. Mixed-user, hourly, historical data are used to train, validate, and evaluate the model. The empirical wavelet transform was used to preprocess the data. Among the perturbing factors, the most influential predictors that were recorded were the weather factors and day type. The developed methodology is upgraded using a novel closed-loop algorithm that uses the forecasting values and influential factors to predict the residuals. Most performance indicators that are computed indicate that forecasting the residuals actually improves the method’s precision, decreasing the mean absolute percentage error from 5.04% to 4.28%. Measured data are used to validate the effectiveness of the presented approach, making it a suitable tool for use in load forecasting by utility companies.

In order to facilitate the creation of an analytical model of a typical urban Medium Voltage distribution grid, an accurate determination of the parameters of the main components is required. As such, the focus of this paper is to determine, compare and validate parameters of transformers and cables through an analytic approach, upfront them with catalog-based data from the manufacturers and construct models as quadripoles. Given that the grid is composed of similar elements, with cables connected in series and transformers connected in parallel from a circuit point of view, constructing the templates for standard transformers and per unit cables allows easy modeling of various feeders for both transient and steady-state regime calculations.

This paper presents calculation of operation modes of power transformers aiming at determination of optimum loading at which the transformer performance coefficient reaches its maximum. Options for increasing the efficiency of power transformers operation at industrial enterprises are proposed.