/library/oar/handle/123456789/15061 2025-11-08T20:12:00Z /library/oar/handle/123456789/138556 Title: Comparative study of monofacial and bifacial solar photovoltaic system performance in the built environment Abstract: Recent advancements in solar photovoltaic (PV) manufacturing technology have witnessed the introduction of bifacial PV modules. The primary distinction lies in their energy generation capabilities, with monofacial modules producing energy solely from the front, while bifacial modules can generate electricity from both the front and back, resulting in higher power output per m². This study aims to analyse typical installation scenarios to determine which technology fits better for the purpose. It investigates whether placing bifacial modules close to the roof, as installers commonly do, is sensible. Furthermore, the contribution of the back surface energy production for different inclinations (15°, 30° and 90°) was assessed. Therefore, this dissertation provides answers to frequently asked questions that are commonly asked by building services engineers, given that all new and renovated buildings will need to achieve net zero-energy status after 2032, according to the forthcoming EU Energy Performance in Buildings Directive. A demonstration setup incorporating both monofacial and bifacial modules was designed and installed to serve as a test bed. Moreover, modelling using Polysun software was applied to further extrapolate the expected yield over a full year, providing valuable insights for conducting a cost-effectiveness analysis for both technologies. Results showed that as the angle of inclination increases, the energy production from the back side of bifacial modules increases, and this contribution becomes more prominent in comparison to frontside energy production on cloudy days, making bifacial modules an ideal candidate for use as sound barriers on arterial roads. Setting bifacial modules at very low angles such as 15° practically defeats the purpose of bi-faciality and this is also true for facade installations. On a micro-scale it was noted that most of the energy generated from the back occurs around solar noon. This means that the inverter needs to be sized accordingly to avoid shaving off the extra energy during peak sunshine hours. If the inverter was undersized, a practice that is widely used for monofacial PV modules, this issue can arise. In comparison, monofacial modules, showed lower overall energy yields under similar conditions, particularly when installed at higher tilt angles. Despite their higher initial costs, bifacial modules demonstrated a superior energy yield and potential for increased cost-effectiveness over time, especially in applications where space constraints and high reflectivity are factors. This highlights the importance of considering bifacial modules for installations where maximizing energy output is critical. Description: M.Sc.(Melit.) 2024-01-01T00:00:00Z /library/oar/handle/123456789/138555 Title: Power quality analysis and improvements within a local hospital Abstract: This master's dissertation investigates power quality (PQ) within a local hospital, aiming to identify, analyse, and mitigate PQ issues that could compromise critical medical equipment and patient safety. Hospitals rely on a stable and reliable power supply to operate essential medical devices and IT systems. Disruptions in PQ, such as voltage sags, spikes, and harmonic distortions, can cause significant operational and safety challenges, including equipment damage and increased maintenance costs. The study begins with a comprehensive PQ assessment using advanced monitoring equipment to collect real-time data on voltage, current, frequency, and harmonics across various hospital departments. Key areas of concern include high-power medical devices like CT scanners, linear accelerators, and chilled water pump sets. The data collected is analysed to pinpoint specific PQ disturbances and their frequencies, magnitudes, and durations. In response to the identified issues, the dissertation proposes targeted mitigation measures, specifically the installation of single-tuned passive filters for the 5th and 7th harmonics. These filters are designed to reduce harmonic distortions and improve overall power quality. The effectiveness of the proposed solutions is evaluated through detailed simulations using MATLAB Simulink, replicating the hospital's electrical distribution system and assessing the impact of the filters. The simulation results indicate that the proposed filters significantly decrease the unwanted harmonics, thereby improving the PQ of the system, enhancing the reliability and safety of the hospital's power supply. The dissertation concludes with recommendations for continuous PQ monitoring and proactive maintenance to prevent future issues, ensuring the hospital can maintain high standards of patient care and operational efficiency. Description: M.Sc.(Melit.) 2024-01-01T00:00:00Z /library/oar/handle/123456789/138553 Title: Investigating the design criteria of battery energy storage systems for large scale commercial projects Abstract: As the growing demand for sustainable energy solutions has increased in recent years, Battery Energy Storage Systems have been identified as one of the sustainable solutions expected to contribute in improving the sustainability of energy systems and efficiently using renewable energy to reduce the reliance on fossil fuels. This dissertation aims to investigate the design and implementation criteria specifically applicable to the deployment of Battery Energy Storage Systems for large commercial buildings. In this context, a comprehensive review of the current state-of-the-art battery storage technologies is carried out, and their applications for commercial project are outlined. The design criteria for sizing and configuring battery storage systems are analysed, in addition to implementation criteria, with particular attention given to fire safety and environmental concerns. The dissertation makes use of a case study to determine the feasibility of deploying a Battery Energy Storage System for a commercial project being designed in Malta. The feasibility of this system is analysed using the System Advisor Model software. Various iterations of simulations were carried out to improved the BESS design from a techno economical perspective and the outcomes were crucial for determining the current feasibility of implementing Battery Energy Storage Systems for similar projects. While implementing such systems proved to have considerable reductions in energy imported from the grid, thus improving on sustainability, the current market rates were still found to be non-economically feasible, and need to be improved to make such systems more effective in the future. Description: M.Sc.(Melit.) 2024-01-01T00:00:00Z /library/oar/handle/123456789/138550 Title: Developing a model for a geothermal heat pump Abstract: Geothermal heat pump (GHP) systems represent a promising solution for sustainable heating and cooling applications, leveraging the stable temperature of the earth’s subsurface. However, these systems encounter two main drawbacks: high initial capital costs and the complexity involved in designing models to accurately predict system performance. Various models exist for vertical heat exchangers (VHEs), including analytical and numerical approaches. Analytical models rely on fundamental heat transfer principles and approximate boreholes as a single heat source, which limits their ability to accurately predict the outlet temperature of the heat exchanger. In contrast to analytical models, numerical methods, particularly 3D simulation software, provide better insights into modeling the complexity of vertical heat exchangers (VHEs). Although these programs can simulate heat exchanger outlet temperatures, they often require significant time and expertise, making them an unattractive choice for quick system analysis. This dissertation focuses on the development and validation of an intuitive computational model that can be used without the need of extensive research and aimed at accurately predicting the performance of a coaxial vertical heat exchanger(VHE). The developed model utilizes time and space discretization techniques to simulate the thermal process of the system and allows for the calculation of both the heat exchanger outlet temperature and also the temperature of the surrounding environment at very short time step intervals. Description: M.Sc.(Melit.) 2024-01-01T00:00:00Z