Assessing Energy Performance and Management Processes in Solar Photovoltaic Farms

La finalidad de la tesis es analizar cualitativamente los procesos de mantenimiento y gestión de las diferentes plantas fotovoltaicas, así como cuantitativamente los resultados de producción de energía solar y determinar las principales causas del funcionamiento actual. Los objetivos son realizar un análisis detallado de todas las características de cada instalación e identificar sus procedimientos de gestión y mantenimiento, recoger los datos de generación de energía y compararlos con un software y comparar los diferentes sistemas fotovoltaicos y aportar recomendaciones de mejora. Se utiliza una metodología para todas las instalaciones fotovoltaicas que incluye un análisis DAFO y una evaluación del rendimiento energético. Los resultados muestran varios puntos en común respecto a los principales problemas de las plantas fotovoltaicas, siguen el mismo patrón respecto a los ratios de generación de energía. Por último, se mencionan las posibles medidas de mejora a tener en cuenta para cada instalación.The purpose of the dissertation is to analyse qualitatively the maintenance and management processes of the different photovoltaic plants, as well as quantitatively the results of solar energy production and determine the main causes for the current operation. The objectives are to perform a detailed analysis of all the characteristics of every installation and identify their management and maintenance procedures, to collect data from energy generation and compare it with a software and compare different PV systems and provide recommendations of improvement. There is a methodology used for all PV sites including a SWOT analysis and a energy performance evaluation. The results show various commonalities regarding the main problems of the photovoltaic plants, they follow the same pattern regarding energy generation ratios. Finally, the possible improvement measures to take into consideration for each installation are mentioned.Departamento de Ingeniería Energética y FluidomecánicaGrado en Ingeniería en Organización Industria

Evolution over Time of Ventilatory Management and Outcome of Patients with Neurologic Disease∗

OBJECTIVES: To describe the changes in ventilator management over time in patients with neurologic disease at ICU admission and to estimate factors associated with 28-day hospital mortality. DESIGN: Secondary analysis of three prospective, observational, multicenter studies. SETTING: Cohort studies conducted in 2004, 2010, and 2016. PATIENTS: Adult patients who received mechanical ventilation for more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 20,929 patients enrolled, we included 4,152 (20%) mechanically ventilated patients due to different neurologic diseases. Hemorrhagic stroke and brain trauma were the most common pathologies associated with the need for mechanical ventilation. Although volume-cycled ventilation remained the preferred ventilation mode, there was a significant (p < 0.001) increment in the use of pressure support ventilation. The proportion of patients receiving a protective lung ventilation strategy was increased over time: 47% in 2004, 63% in 2010, and 65% in 2016 (p < 0.001), as well as the duration of protective ventilation strategies: 406 days per 1,000 mechanical ventilation days in 2004, 523 days per 1,000 mechanical ventilation days in 2010, and 585 days per 1,000 mechanical ventilation days in 2016 (p < 0.001). There were no differences in the length of stay in the ICU, mortality in the ICU, and mortality in hospital from 2004 to 2016. Independent risk factors for 28-day mortality were age greater than 75 years, Simplified Acute Physiology Score II greater than 50, the occurrence of organ dysfunction within first 48 hours after brain injury, and specific neurologic diseases such as hemorrhagic stroke, ischemic stroke, and brain trauma. CONCLUSIONS: More lung-protective ventilatory strategies have been implemented over years in neurologic patients with no effect on pulmonary complications or on survival. We found several prognostic factors on mortality such as advanced age, the severity of the disease, organ dysfunctions, and the etiology of neurologic disease