Development of a loop heat pipe 'LHP' thermal superconductor device with multicondensors

164 p.El mundo electrónico, en su avance en el incremento de integración ha llegado a un cuello de botella en su progresión en la miniaturización e integración. Este cuello de botella es la elevada densidad de flujo de calor generado por los componentes actuales a pesar del avance en los materiales menos resistivos. Esto hace que las tecnologías convencionales de refrigeración ya no sean válidas en cualquier aplicación, (limitaciones de tamaño y capacidad de extracción de calor) y sea preciso otras tecnologías más eficientes y de menor tamaño. Los dispositivos Loop Heat Pipe (LHP) se presentan como aquellos que satisfacen los requerimientos de tamaño y capacidad exigidos por el mundo electrónico, termoeléctrico. La presente Tesis Doctoral versa sobre el desarrollo de un dispositivo LHP para lo cual se ha elaborado un modelo fluido-térmico en régimen estacionario de la física que caracteriza estos dispositivos. Modelo que, a diferencia de los existentes en bibliografía, incorpora una función que determina el flujo de calor hacia la cámara de compensación. Así mismo, se realiza una labor de caracterización, análisis del efecto de bombeo capilar de diferentes tecnologías capilares (mallas, sinterizado, SLM, ...) a fin de cuantificar la influencia de determinados parámetros en su capacidad de bombeo o curva de carga. Por último, se construye y ensaya un prototipo LHP para la refrigeración del array de LEDs de una lámparaSCM: Sostenibilidad, Construcción y Materiales. Grupo de innovación y diseñ

Development of a loop heat pipe 'LHP' thermal superconductor device with multicondensors

164 p.El mundo electrónico, en su avance en el incremento de integración ha llegado a un cuello de botella en su progresión en la miniaturización e integración. Este cuello de botella es la elevada densidad de flujo de calor generado por los componentes actuales a pesar del avance en los materiales menos resistivos. Esto hace que las tecnologías convencionales de refrigeración ya no sean válidas en cualquier aplicación, (limitaciones de tamaño y capacidad de extracción de calor) y sea preciso otras tecnologías más eficientes y de menor tamaño. Los dispositivos Loop Heat Pipe (LHP) se presentan como aquellos que satisfacen los requerimientos de tamaño y capacidad exigidos por el mundo electrónico, termoeléctrico. La presente Tesis Doctoral versa sobre el desarrollo de un dispositivo LHP para lo cual se ha elaborado un modelo fluido-térmico en régimen estacionario de la física que caracteriza estos dispositivos. Modelo que, a diferencia de los existentes en bibliografía, incorpora una función que determina el flujo de calor hacia la cámara de compensación. Así mismo, se realiza una labor de caracterización, análisis del efecto de bombeo capilar de diferentes tecnologías capilares (mallas, sinterizado, SLM, ...) a fin de cuantificar la influencia de determinados parámetros en su capacidad de bombeo o curva de carga. Por último, se construye y ensaya un prototipo LHP para la refrigeración del array de LEDs de una lámparaSCM: Sostenibilidad, Construcción y Materiales. Grupo de innovación y diseñ

Nanofluid as Advanced Cooling Technology. Success Stories

Nanofluids are defined as heat transfer fluids with enhanced heat transfer properties by the addition of nanoparticles. Nanofluid’s stability, nanoparticles’ type and their chemical compatibility with the base fluid are essential not only to increase the nanofluid’s thermophysical properties but also to ensure a long-lasting and thermal efficient use of the equipment in which it is used. Some of these aspects are discussed in this chapter. Likewise, the improvement in terms of the heat transfer capacity (thermal resistance) that the use of nanofluids has on the heat pipes-thermosyphons is shown. On the other hand, the improvement in energy efficiency that nanofluid causes in a vapor compression system is also presented

Development of a loop heat pipe 'LHP' thermal superconductor device with multicondensors

164 p.El mundo electrónico, en su avance en el incremento de integración ha llegado a un cuello de botella en su progresión en la miniaturización e integración. Este cuello de botella es la elevada densidad de flujo de calor generado por los componentes actuales a pesar del avance en los materiales menos resistivos. Esto hace que las tecnologías convencionales de refrigeración ya no sean válidas en cualquier aplicación, (limitaciones de tamaño y capacidad de extracción de calor) y sea preciso otras tecnologías más eficientes y de menor tamaño. Los dispositivos Loop Heat Pipe (LHP) se presentan como aquellos que satisfacen los requerimientos de tamaño y capacidad exigidos por el mundo electrónico, termoeléctrico. La presente Tesis Doctoral versa sobre el desarrollo de un dispositivo LHP para lo cual se ha elaborado un modelo fluido-térmico en régimen estacionario de la física que caracteriza estos dispositivos. Modelo que, a diferencia de los existentes en bibliografía, incorpora una función que determina el flujo de calor hacia la cámara de compensación. Así mismo, se realiza una labor de caracterización, análisis del efecto de bombeo capilar de diferentes tecnologías capilares (mallas, sinterizado, SLM, ...) a fin de cuantificar la influencia de determinados parámetros en su capacidad de bombeo o curva de carga. Por último, se construye y ensaya un prototipo LHP para la refrigeración del array de LEDs de una lámparaSCM: Sostenibilidad, Construcción y Materiales. Grupo de innovación y diseñ

Li2CO3 as Protection for a High-Temperature Thermoelectric Generator: Thermal Stability and Corrosion Analysis

In most steelmaking processes, huge amounts of waste heat at high temperature (700–800 °C) are thrown into the environment without any use. An alternative use for this waste heat is electricity generation through thermoelectric generators. However, these high temperatures, as well as their fluctuations over time, affect not only the conversion rate of the thermoelectric generator but also its useful lifetime. The incorporation of a latent thermal energy storage (TES) system could be a solution; nevertheless, the thermal stability and corrosive effect of the (PCM) phase change material are key aspects for the thermal storage system definition, in terms of durability. In this work, developed in the framework of the European project “PowGETEG” (RFSR-CT-2015-00028, funded by the Research Fund for Coal and Steel), a high-temperature analysis (700–800 °C) of the Li2CO3 thermal properties, thermal stability and corrosive effect on the AISI 304 and AISI 310 stainless steels is carried out. The results show that the eutectic salt Li2CO3 exhibits high thermal stability with neither change in its thermal properties nor material degradation. This work shows that lithium carbonate Li2CO3 and AISI 310 make a very good combination for the definition of a thermal storage system able to protect a high-temperature thermoelectric converter from temperature variations, making it more reliable

Impact of successful treatment with direct-acting antiviral agents on health-related quality of life in chronic hepatitis C patients.

BACKGROUND:Direct-acting antivirals (DAA) have demonstrated high efficacy to achieve sustained virological response (SVR) in chronic hepatitis C patients. We aim to assess the change in health-related quality of life (HRQoL) among patients successfully treated, and to identify predictors of this variation. METHODS:In a prospective observational study, patients with chronic hepatitis C who started DAA therapy between May 2016 and April 2017 completed the EQ-5D-5L questionnaire at baseline and 12 weeks after the end of therapy before knowing the virological result. Analysis included all patients with SVR. RESULTS:Median baseline EQ-5D-5L scores of the 206 enrolled patients were 0.857 utility and 70.0 visual analogue scale (VAS). Following SVR, a reduction occurred in the proportion of patients with mobility problems (35% vs 24%, p = 0.012), pain/discomfort (60% vs 42%, p<0.001) and anxiety/depression (57% vs 44%, p = 0.012), with an increase in utility (+0.053, p<0.001) and VAS (+10, p<0.001). Score improvements were also observed in cirrhotic (+0.048 utility, p = 0.027; +15 VAS, p<0.001) and HIV co-infected patients (+0.039 utility, p = 0.036; +5 VAS, p = 0.002). In multivariate analyses, middle age (45-64 years) and baseline anxiety/depression were associated to greater improvement in utility after SVR, and moderate-advanced liver fibrosis and cirrhosis to greater increase in VAS score. Low baseline values were associated to greater improvements in utility value and VAS score. CONCLUSIONS:The cure of chronic hepatitis C infection with DAA has a short term positive impact on HRQoL with improvement in mobility, pain/discomfort, anxiety/depression, utility value and VAS score. Patients with poor baseline HRQoL were the most beneficed

Progress in the elimination of hepatitis C virus infection: A population-based cohort study in Spain.

BackgroundThe World Health Organization set targets to eliminate hepatitis C virus (HCV) infection through detection and treatment of all cases by 2030. This study aimed to describe the progress and difficulties in the elimination of HCV infection in Navarra, Spain.MethodsUsing electronic healthcare databases, we performed a population-based prospective cohort study to describe changes in the prevalence of diagnosed active HCV infection at the beginning of 2015 and the end of 2017, the rate of new diagnoses and the rate of post-treatment viral clearance (PTVC) during this period.ResultsAt the beginning of 2015 there were 1503 patients diagnosed with positive HCV-RNA, 2.4 per 1000 inhabitants, and at the end of 2017 the prevalence had decreased by 47%. In the study period, 333 (18 per 100,000 person-years) new positive HCV-RNA cases were detected, but only 76 (23%; 4.2 per 100,000 person-years) did not have anti-HCV antibodies previously detected. Prevalent cases and new diagnoses of active infection were more frequent in men, people born in 1950-1979, HIV-infected patients and in those with lower income levels. Among patients with HCV-RNA, 984 achieved PTVC (22.7 per 100 person-years). PTVC was less frequent in patients born before 1940, in immigrants and in patients with lower income levels.ConclusionsThe prevalence of diagnosed active HCV infection has dropped by almost half over three years, because the number of patients with PTVC was much higher than the number of new diagnoses. Interventions specifically targeted at population groups with less favourable trends may be necessary

Progress in the elimination of hepatitis C virus infection in Spain: a population-based cohort study

Background: The World Health Organization set targets to eliminate hepatitis C virus (HCV) infection through detection and treatment of all cases by 2030. This study aimed to describe the progress and difficulties in the elimination of HCV infection in Navarra, Spain. Methods: Using electronic healthcare databases, we performed a population-based prospective cohort study to describe changes in the prevalence of diagnosed active HCV infection at the beginning of 2015 and the end of 2017, the rate of new diagnoses and the rate of post-treatment viral clearance (PTVC) during this period. Results: At the beginning of 2015 there were 1503 patients diagnosed with positive HCV-RNA, 2.4 per 1000 inhabitants, and at the end of 2017 the prevalence had decreased by 47%. In the study period, 333 (18 per 100,000 person-years) new positive HCV-RNA cases were detected, but only 76 (23%; 4.2 per 100,000 person-years) did not have anti-HCV antibodies previously detected. Prevalent cases and new diagnoses of active infection were more frequent in men, people born in 1950-1979, HIV-infected patients and in those with lower income levels. Among patients with HCV-RNA, 984 achieved PTVC (22.7 per 100 person-years). PTVC was less frequent in patients born before 1940, in immigrants and in patients with lower income levels. Conclusions: The prevalence of diagnosed active HCV infection has dropped by almost half over three years, because the number of patients with PTVC was much higher than the number of new diagnoses. Interventions specifically targeted at population groups with less favourable trends may be necessary