/library/oar/handle/123456789/66078 2025-12-26T20:27:34Z 2025-12-26T20:27:34Z /library/oar/handle/123456789/66981 2021-01-11T14:50:50Z 2020-01-01T00:00:00Z

Title: Analysing the "performance gap" between energy performance certificates and actual energy consumption of non-residential buildings in Malta Abstract: The updated EU energy performance of buildings directive 2018/844 stipulates that measures need to be taken to accelerate building renovation to achieve carbon neutrality by 2050. A key tool is the energy performance certificates (EPCs), which so far have proved to be virtually ineffective in driving change, due to the low level of trust in their credibility. This is mainly manifested by the existence of a significant energy “performance gap” between the EPC and the building’s actual energy use intensity. This thesis has investigated this “performance gap” between the non-residential national software SBEM-mt and the actual energy use intensity for three non-residential clusters having different building services’ engineering complexities, and found it to be both significant and unpredictable for all of them. An alternative approach based on operational rating has been proposed, which considers the actual energy consumption of a building, in order to determine its energy use intensity (EUI). Inspired by the UK benchmarks for non-residential buildings, a dynamic, transparent, reliable and repeatable tool has been developed, whereby good practice benchmarks for 29 non-residential categories have been calculated for Malta, based on the concept that energy use in buildings may be split into weather-independent and weather-dependent components. The tool considers a systematic bottom-up approach taking into consideration Malta’s total degree days, ventilation requirements, heating load as well as sensible and latent cooling loads, besides others. Results showed that the total EUI for the different categories is very similar to that of the UK. Malta’s total degree days are lower, yet, the latent load for cooling more than counterbalances the lower heating demand. Comparison between the results of this tool and the actual EUIs for the three cluster buildings was found to be convergent and consistent. The tool can be used to provide Malta with verified benchmarks upon which policies and energy investment decision making can be based to achieve an improved efficient energy rating towards the road to carbon neutrality. Description: PH.D.SUS.ENERGY

2020-01-01T00:00:00Z /library/oar/handle/123456789/66979 2021-01-11T14:50:24Z 2020-01-01T00:00:00Z

Title: A study of ageing of photovoltaic system energy output in Malta Abstract: As the ever-growing solar industry expands across the globe and Malta, it is important to understand all of the aspects that affect their performance. One of these is ageing, which is a long-term type of degradation that results in a reduction in energy output. The rate at which this ageing is experienced appears to vary in different climates and system to system and is dependent upon many aspects. The aim of this work is to find the degradation rate of four systems operating in Malta by direct power measurements. Energy output data for three of the four systems was obtained from the Sunny Portal website while the fourth system’s data was obtained from a private individual. Data from April to August was studied as this time period would increase the likelihood of fully sunny days which removes some of the variability of partially cloudy days. Two systems are polycrystalline while the other two are monocrystalline. Five methods were used in order to calculate the apparent degradation rates experienced by the systems. The first method involved plotting the entire data sets of energy production. The second method refined the first approach by plotting the individual months by year and the monthly averages. These approaches had very similar results but the first method understandably has a lot more noise. Method 3 involved the plotting of the average of the seven highest energy outputs from the months across the years. This ensured that only cloudless days were used. Method 4 incorporated weather data (temperature and irradiance) alongside energy output data, with days with the same conditions of individual months being plotted across the years. Method 5 took this approach even further, as specific hourly data was used for energy output, temperature and irradiance. This method was applied to three of the four systems, as one of the system’s hourly data was not available. Method 1 results were not taken into consideration as they were deemed less reliable due to the extensive variability over a whole year. Method 2 results ranged from -0.7% per year up to -1.5% per year. Method 3 results were between -0.4% and -1.0% annually. Method 4 results were calculated to be between -0.9% and -1.2% while method 5 results had the widest range from -0.1% to -1.5% per year. A clear decline is evident through methods 2 to 5 and also appears when looking at the annual production data for the systems. The actual degradation rate experienced by these systems is likely in the range of the values found in the methods 2 to 4 ranging from -0.4% to -1.5% per year, with method 5 results likely being too low for two of the systems. No appreciable difference in energy output decline between the monocrystalline and polycrystalline was observed. Description: M.SC.SUS.ENERGY

2020-01-01T00:00:00Z /library/oar/handle/123456789/66978 2021-01-11T14:49:47Z 2020-01-01T00:00:00Z

Title: A comparative study of the global warming potential of hydrogen fuel cell cars and electric cars with a special focus on the Maltese islands Abstract: The ever-increasing emissions originating from the transportation sector calls for a shift to alternative cleaner fuels. Besides the electric car, the hydrogen fuel cell vehicle is slowly gaining momentum. The only by-product of the reaction between hydrogen and oxygen from the air is water, hence they are considered as zero-emission. A life cycle assessment (LCA) is being conducted to analyse the processes carried out from the manufacturing phase to the end-of-life phase of a hydrogen vehicle. Although a fuel cell vehicle is considered to be emission-free, there are other implications which are analysed, such as the hydrogen production method and the electricity mix used. As a matter of fact, Malta’s emissions from electricity generation stand at 489 gCO2/kWh, and hydrogen production using Malta’s electricity mix, still generates a considerable amount of emissions although much less than an internal combustion engine vehicle. Hydrogen production in the study is assumed to be produced by electrolysis, as planned in the Malta National Electromobility Action Plan. The three implementation scenarios have been created to estimate the hydrogen requirement. The hydrogen demand for the first two scenarios can be met by two electrolysis plants, but for the third, a total of fourteen electrolysis facilities will be needed. Advanced electrolysis technologies are becoming more viable and energy efficient. However, the aim is to have electrolysis plants which operate by energy from renewables, to reduce the emissions from the atmosphere as much as possible. Additionally, the production of hydrogen from renewables, can potentially put fuel cell vehicles at the forefront in the transportation sector. Furthermore, both electric and fuel cell vehicles are the way forward towards a cleaner atmosphere with reduced emissions. While electric vehicles have already established a market on the Island, fuel cells vehicles are only present in a few countries. Moreover, the plan to ban imports on fossil fuel cars, will shift the focus on both electric and fuel cell vehicles, as proposed in Directive 2014/94/EU. This emerging technology may take a while until it is integrated within the transportation sector in Malta, however, grants and schemes will encourage the presumably gradual investment in hydrogen fuel cell vehicles. Description: M.SC.SUS.ENERGY

2020-01-01T00:00:00Z /library/oar/handle/123456789/66977 2021-01-11T14:49:23Z 2020-01-01T00:00:00Z

Title: An evaluation of treatment process options for the retrofit of an existing urban wastewater treatment plant with a focus on energy efficiency Abstract: The wastewater treatment industry faces severe challenges due to sudden increases in populations and hence increased sewage flows to the plants along with harsher regulations from the EU and other regulatory bodies to meet effluent quality requirements. In addition to this, is also the reduction in the specific energy which is becoming more of a concern as time passes, and plants are looking for ways to decrease the energy and carbon footprint. This report describes retrofit options for extended aeration activated sludge process in IĊ-Ċumnija wastewater treatment plant. The main aim of this research was to establish a process that will allow the treatment of an increased influent flow. The two main constraints were to use the existing plant footprint without extensive additional civil works that will result in downtime and to use the existing electrical power usage or less. The processes were narrowed down to Moving Bed Biological Reactor (MBBR) and Integrated Fixed-Film Activated Sludge (IFAS) as both meet the mentioned constraints and show good improvement potential. The evaluation of the MBBR and IFAS processes with respect to the current extended aeration process was performed through BioWin by EnviroSim, a wastewater simulation software. The model was configured and calibrated based on drawings and data of the plant, meetings with engineers and operators, and site visits involving onsite measurements and tests along with observations. This preliminary study gives a good insight of the potential effluent quality for the technological solution that was the preferred option of the plant engineer. However, Integrated Fixed Film Activated Sludge (IFAS) process is not eliminated by this option. The simulation was done using different media surface areas and reactor media fill factors. The effluent parameters BOD, COD and N improved by 4% with a reduction of 0.093 kWh per m3of effluent. The MBBR upgrade will allow a 50% increase in the influent flow while still meeting the BOD, COD and N values of the current process at 10000m3/day of influent. Description: M.SC.SUS.ENERGY

2020-01-01T00:00:00Z