Real Fernández, Antonio

El constante aumento de la población mundial, así como de las zonas urbanas, que ha tenido lugar en las últimas décadas, ha provocado un aumento progresivo de las emisiones de CO2 acelerando el calentamiento global del planeta. Los sistemas de refrigeración suponen un porcentaje importante del consumo eléctrico en países desarrollados, por lo que contribuyen a la emisión de estos gases de efecto invernadero. La concienciación sobre el cambio climático ha llevado a la mayoría de países a plantearse cuotas de reducción de emisiones de CO2, siendo la eficiencia energética una herramienta indispensable para alcanzar estos objetivos. Los sistemas de almacenamiento térmico han demostrado que pueden contribuir a aumentar la eficiencia de los sistemas de refrigeración mediante distintas estrategias de funcionamiento, basándose, la mayoría de ellas, en un desplazamiento de los consumos a periodos de mayor rendimiento de la instalación. Los materiales de cambio de fase son ampliamente utilizados en estos sistemas de almacenamiento debido a su elevada densidad energética y a su alta capacidad de almacenamiento térmico en un estrecho rango de temperaturas. En la presente tesis se estudiará el uso de un depósito de almacenamiento térmico para mejorar la eficiencia de un sistema de bomba de calor con disipación aerotérmica en su funcionamiento como enfriadora. Este depósito servirá como método de disipación de calor alternativo a la disipación aerotérmica, de modo que pueda optarse, en cada momento, por la opción más eficiente. De este modo, durante los periodos de elevada temperatura exterior, donde la disipación aerotérmica presenta una baja eficiencia disminuyendo el rendimiento de la enfriadora, el depósito de almacenamiento térmico proporcionará un foco de disipación de calor a temperatura constante que permitirá a la enfriadora trabajar con un mayor rendimiento. Este depósito será enfriado de nuevo para el siguiente uso cuando la temperatura exterior descienda. Para analizar el funcionamiento del sistema de climatización descrito se han realizado, en primer lugar, una serie de ensayos experimentales sobre una instalación adaptada para tal fin. A continuación, se han utilizado estos ensayos para diseñar y validar un modelo de cada uno de los componentes que configuran la instalación. Estos modelos han sido acoplados para conformar un modelo global del sistema de climatización propuesto. Utilizando este modelo se han podido realizar simulaciones del comportamiento del sistema bajo distintas condiciones de trabajo lo que ha permitido evaluar su rendimiento y compararlo con el de un sistema de climatización con disipación aerotérmica convencional. Tras la simulación de distintos escenarios se ha obtenido una mejora del COP del 8.01% para funcionamiento a plena carga de la enfriadora con un perfil de demanda constante, valor que asciende hasta un 12.48% si se considera un funcionamiento a carga parcial. Por último, se ha simulado el comportamiento del sistema bajo un perfil real de demanda para una vivienda, obteniéndose una mejora del COP del 7.4%. / The continuous increase in the world population and urban areas in the last decades has caused a progressive increase in the CO2 emissions accelerating global warming. Refrigeration systems stand for an important share of electrical consume in developed countries which contributes to the emission of these greenhouse gases. Concern about climate change has led most countries to consider the reduction of CO2 emissions, where energy efficiency is an important mean to achieve this objective. Thermal storage systems have proved their contribution in increasing the efficiency of refrigeration systems through different operating strategies, based, most of them, in the displacement of consumption to periods with better performance of the plant. Phase change materials are widely used in these storage systems due to its high energy density and its high thermal storage capacity in a narrow temperature range. In this thesis, the use of a thermal storage tank to improve the efficiency of an air condensed heat pump working as a chiller will be studied. This tank will be used as a method to reject the heat alternative to aerothermal dissipation so the most efficient option can be chosen at any moment. Thus, during the periods with high outside temperature, when aerothermal dissipation shows a low efficiency reducing the performance of the chiller, the storage tank will provide a heat sink to reject the heat at a constant temperature, allowing the chiller to work with a higher efficiency. The tank will be cooled again for its next use when the outside temperature falls. To analyze the performance of the described air-conditioning system, a set of experimental tests has been carried out using a lab facility adapted for this purpose. Then, these tests have been used to design and validate a model for each component that makes up the installation. These models have been linked up to form a global model of the proposed air-conditioning system. Using this model, simulations have been carried out to study the performance of the system under different working conditions, evaluating its performance and comparing it with that of a conventional aerothermal dissipation air conditioning system. After simulating different scenarios an improvement of the COP of 8.01% has been obtained for a full load performance of the chiller with a constant demand profile. This improvement rises to 12.48% if a partial load performance is considered. Finally, a simulation has been carried out for a real demand profile for a house, where a 7.4% improvement of the COP has been obtained.

Achieving European climate neutrality by 2050 requires further efforts not only from the industry and society, but also from policymakers. The use of high-efficiency cogeneration facilities will help to reduce both primary energy consumption and CO2 emissions because of the increase in overall efficiency. Fuel cell-based cogeneration technologies are relevant solutions to these points for small- and microscale units. In this research, an innovative and new fuel cell-based cogeneration plant is studied, and its performance is compared with other cogeneration technologies to evaluate the potential reduction degree in energy consumption and CO2 emissions. Four energy consumption profile datasets have been generated from real consumption data of different dwellings located in the Mediterranean coast of Spain to perform numerical simulations in different energy scenarios according to the fuel used in the cogeneration. Results show that the fuel cell-based cogeneration systems reduce primary energy consumption and CO2 emissions in buildings, to a degree that depends on the heat-to-power ratio of the consumer. Primary energy consumption varies from 40% to 90% of the original primary energy consumption, when hydrogen is produced from natural gas reforming process, and from 5% to 40% of the original primary energy consumption if the cogeneration is fueled with hydrogen obtained from renewable energy sources. Similar reduction degrees are achieved in CO2 emissions.

Introducción: La giardiosis es una parasitosis gastrointestinal de impacto en salud pública. Pacientes y métodos: Estudio observacional de los casos, en menores de 15 a˜nos, atendidos durante el periodo 2012-2019 en el Departamento 3 de Salud de la Provincia de Castellón (Espa˜na). Resultados: Se registraron 190 casos en menores de 15 a˜nos. El número de casos varió significativamente según grupo etario (55% en el grupo de 0-4 a˜nos) y momento del a˜no (mayoría en agosto-noviembre). El índice de masculinidad resultó de 115. Los síntomas más frecuentes fueron diarrea y dolor abdominal. El tratamiento más empleado fue metronidazol en pauta estándar (80% de los pacientes). El 13% de los casos presentaron coinfección y el 36% comorbilidades, principalmente dermatitis atópica e intolerancia a la lactosa/fructosa. Se registró un 8% de recidivas/reinfecciones. Todos los casos se diagnosticaron por tests coproparasitológicos convencionales y algunos, además, con inmunocromatografía (63 casos). Treinta y cinco muestras fueron confirmadas para Giardia duodenalis por qPCR, descartándose sesgo diagnóstico. Se detectó un sesgo de notificación a escala nacional para el periodo 2012-2016. El coste sanitario directo por paciente resultó de 117D. Conclusiones: La giardiosis es una enfermedad vigente en nuestra región que debe ser considerada (en el diagnóstico diferencial) como diagnóstico probable de patología gastrointestinal ante un ni˜no menor de cuatro a˜nos con diarrea y dolor abdominal. Su correcto manejo clínico disminuiría la posibilidad de empeoramiento del paciente y evitaría la hospitalización, reduciendo el impacto económico de la patología en términos de costes directos sanitarios. / Introduction: Giardiasis is a gastrointestinal parasitosis that has a great public health impact. Patients and methods: Observational case study - in children under 15 years old in the Health Department 3 of the Province of Castellon (Spain), during the period 2012-2019. Results: A total of 190 cases of giardiasis were recorded in children under 15 years old. The number of cases varied significantly according to age group and month of the year. There were 115 males. The most frequent symptoms were diarrhea and abdominal pain. The most commonly used treatment was standard metronidazole (80% of patients). Co-infection occurred in 13% of cases, and comorbidities in 36%, especially atopic dermatitis and lactose/fructose intolerance. Relapses and/or re-infections were recorded in 8%. All cases were diagnosed by conventional parasitological stool tests and complementary immunochromatography (63 cases). Thirty-five samples were positive for Giardia duodenalis by qPCR. The direct health cost per patient was 117D . A disease notification bias was detected between 2012-2016 at a national scale. Conclusions: Giardiasis is a current disease in Castellon, and should be considered as a probable diagnosis of gastrointestinal disease in a child under 4 years-old with diarrhea and abdominal pain. Its correct clinical and therapeutic management could reduce the possibility of worsening of the patient’s condition and, additionally, would reduce the economic impact of the disease in terms of direct health costs.

Phase change materials (PCMs) can be used in refrigeration systems to redistribute the thermal load. The main advantages of the overall system are a more stable energy performance, energy savings, and the use of the off-peak electric tariff. This paper proposes, models, tests, and analyzes an experimental water vapor compression chiller connected to a PCM thermal energy storage (TES) tank that acts as an alternative heat sink. First, the transient model of the chiller-PCM system is proposed and validated through experimental data directly measured from a test bench where the PCM TES tank is connected to a vapor compression-based chiller. A maximum deviation of 1.2 C has been obtained between the numerical and experimental values of the PCM tank water outlet temperature. Then, the validated chiller-PCM system model is used to quantify (using the coeffcient of performance, COP) and to analyze its energy performance and its dependence on the ambient temperature. Moreover, electrical energy saving curves are calculated for different ambient temperature profiles, reaching values between 5% and 15% taking the experimental system without PCM as a baseline. Finally, the COP of the chiller-PCM system is calculated for di erent temperatures and use scenarios, and it is compared with the COP of a conventional aerothermal chiller to determine the switch ambient temperature values for which the former provides energy savings over the latter.