https://www.um.edu.mt/library/oar/handle/123456789/130231 Tue, 05 May 2026 15:55:41 GMT 2026-05-05T15:55:41Z https://www.um.edu.mt/library/oar/handle/123456789/130603 Title: Investigating wind variations within the atmospheric boundary layer : a Maltese case study using LiDAR Abstract: Conventional wind monitoring masts, with sensors at multiple levels, have typically formed an essential part of wind measurement campaigns to gauge wind parameters and climatological behaviour at a potential wind turbine site. As bigger, megawatt-class wind turbines are being introduced into the market, monitoring masts need to be taller to reach the machines’ hub height. However, this results in costlier masts and in particular, makes offshore measurements more challenging. Therefore, remote sensing technologies, such as Light Detecting and Ranging (LiDAR), are becoming increasingly popular due to the precise nature in which they capture wind flow data at altitudes beyond those attainable with traditional monitoring masts. In July 2022 a LiDAR wind measurement system was set up atop the White Tower at l- Aħrax limits of Mellieħa, Malta. Over the course of one calendar year (12 months), spanning from 1 September 2022 to 31 August 2023, data was collected by this LiDAR unit at 10 different heights ranging from 11 m to 191 m above the unit’s window (20 m and 200 m above ground level, respectively). As a result, data collected enabled a more detailed analysis, besides that of wind speed, wind direction, standard deviation of wind speed, turbulence intensity, and temperature. The variation of wind speed shear and wind direction shear were assessed independently and in relation with other collected wind parameters on monthly and cumulative 12-month basis. The objective of this study was to assess the variation of wind within the atmospheric boundary layer at a coastal location in Malta. This study ensued by collecting raw data at the coastal location namely wind speed, wind direction, turbulence intensity, and atmospheric temperature. Whilst the raw data was assessed, their variations, namely wind speed shear and wind direction shear also underwent analysis. The horizontal wind speed at the White Tower measurement was observed to increase with elevation with an overall average of 6.33 ms-1 at 100 m. The diurnal average horizontal wind speed pattern shows that this is low during the night and higher during the day. Furthermore, the vector average wind direction varied from 280.09° (west) at 20 m to 290.73° (west-northwest) at 200 m. In addition, the vector average wind direction at 100 m at the White Tower site was 288.07° (west-northwest). The wind shear exponent yielded was 0.0468 which is significantly lower than the 1/7 (0.14) value generally adopted by the power law. Moreover, the average wind shear exponent increased in magnitude as lower heights were eliminated from the wind shear value derived using the power with values being in line with that observed in literature. Furthermore, the diurnal pattern revealed that the shear exponent decreases during the daytime and increases at nighttime. On the other hand, the variation of the average shear exponent during warm months is observed to be higher during the night whilst negative shear exponent values were noted during daytime. Monthly variations of the average wind direction shear showed no distinct pattern in the difference between the pairs of heights assessed i.e., 200 m & 20 m, 200 m & 100 m, and 100 m & 20 m respective pairs. However, the diurnal variation of the average change in wind direction fluctuates during the warm months, whereas a relatively constant average change in wind direction with minor fluctuations is observed during the cool months. Average wind direction changes are also greater during warm months than those observed during cool months. The turbulence intensity is noted to decrease with higher elevation ranging from 13.1% at 20 m to 9.2% at 200 m. Moreover, the diurnal variation in average turbulence intensity demonstrates fluctuations over the 24-hour period, with higher values during the day and lower values during the night. At the 100 m measurement height, turbulence intensity was highest at low wind speeds and decreased as wind speed increases. Description: M.Sc.(Melit.) Sust.Energy Mon, 01 Jan 2024 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/130603 2024-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/130602 Title: Assessing the impact of energy efficiency measures on building performance and resident behaviour : a case study of social & private housing in Malta Abstract: Energy efficiency behaviour is a complex matter which is related to the interaction between human behaviour and energy consumption. Understanding residents' behaviour could help to mitigate emissions from Malta's building sector, which has witnessed a rise in greenhouse gas (GHG) emissions over the past two decades. The aim of this dissertation is to analyse the energy building performance as well as the behaviour of residents within Malta’s first energy efficient social housing project, the Tal-Ftieh complex. Additionally, a sample of beneficiaries from the Irrinova Darek and Regulator for Energy and Water Services (REWS) Roof thermal insulation and double-glazing financial support initiatives were also included in the study. This research involved a mixed-method approach, which included interviews, temperature and humidity monitoring within the dwellings using data loggers, collection of data from energy bills, and energy performance calculation utilising Design Builder software specifically for the Tal-Ftieh housing project. The results from the DesignBuilder software indicate that the Tal-Ftieh housing apartments are energy efficient as their energy performance is lower than the national average. However, the data collected from the latest available energy bills shows relatively higher energy consumption and also notable variation amongst the participants. Moreover, their daily per capita energy consumption also tends to exceed that of participants from both the REWS and Irrinova Darek schemes. This highlights the important role of residents’ energy behaviour. As regards thermal comfort, the measured indoor temperature of the Tal-Ftieh participants exceeded the international guidelines on several occasions. Furthermore, the measured indoor humidity levels were also high for all participants most of the time, especially for the participants from the REWS scheme, who reside in terraced houses. Meanwhile, the results from the interviews showed that the tal-Ftieh participants had poor knowledge regarding the energy efficient measures installed in the building and this affected their energy behaviour. This scenario contrasts with the REWS and Irrinova Darek beneficiaries for whom the energy efficiency measures constituted an investment risk. Another important finding from the research was that the primary motivator for investing in energy efficient measures is cost savings. Based on these findings, the dissertation presents a number of policy recommendations to enhance energy efficiency behaviour in Malta and make progress towards reducing emissions from the residential building sector. Description: M.Sc.(Melit.) Sust.Energy Mon, 01 Jan 2024 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/130602 2024-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/130600 Title: Design and testing of a modular photovoltaic and insulation solution for flat roofs Abstract: The study presented in this dissertation sought to design, develop, and test a combined modular photovoltaic and insulation solution for flat roofs, which was based on a conceptual design referred to as MedSolar. MedSolar sought to present a building integrated photovoltaic which is specifically designed for the requirements of Malta, and other countries with similar climatic conditions, adding value in terms of increased energy generation, minimised aesthetics and improved ease of installation This study optimised the initial conceptual design, and further altered the optimised design into a prototype, resulting in nine variants with most of them tested. The design incorporated features such as insulation, reflectors placed within the space between two sets of custom designed photovoltaic (PV) modules, wiring embedded within the design, and modularity features. An experimental campaign studied the energy generated from set ups with the following configurations: Flat PVs, PVs with a tilt angle of 30° with and without reflectors, and PVs with a tilt angle of 15° with and without reflectors. The experiment also studied the impact of the design itself had on the performance of the full-scale prototype. Data from different seasons were collected, and overall, the configuration with reflectors having PVs tilted at 30° yielded the best results. The same configuration was found to produce exceptional results during the summer month, with the reflector aiding in an increase of 15% in energy generation when compared to its counterpart without reflector whilst at the same time shielding the MedSolar tile from direct solar irradiance. Reflectors used for the configuration with PVs tilted at 15° were also found to be very effective, but not effective during the summer months. In addition, reflectors were found to be effective on days with significant cloudiness, leading to the conclusion that reflectors were effective in reflecting diffused irradiance onto the surface of the opposing custom PV module. In addition, reflectors from adjacent PV modules were found to be positively impacting electricity generation. Finally, this study contributed towards the research in the field of insulation incorporated within building integrated photovoltaics (BIPVs), which during the Literature Review was found to be very limited. Testing of the effectiveness of insulation during the summer months found that insulation incorporated within the proposed tiles was very effective, resulting in a significant reduction in the U-Value when compared to the original U-Value of the roof section that was studied. Description: M.Sc.(Melit.) Mon, 01 Jan 2024 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/130600 2024-01-01T00:00:00Z