State-of-the-Art for the use of Phase-Change Materials in Tanks Coupled with Heat Pumps

With the goal of increasing heat storage in the same accumulation volumes, phase-change materials are considered. There are different substances with different phase-change temperatures that can be used for storing heating or cooling implemented in heat pump systems for applications of space heating and cooling, ventilation or domestic hot water production. Reducing the size of the buffer tanks used with heat pumps, avoiding the oversizing of heat pumps or detaching thermal energy production and consumption are among the benefits that could result from the combination of heat pumps and latent heat thermal energy storage. In addition, this form of thermal energy storage allows enhancing the use of renewable energy sources as heat sources for heat pump systems. Most previous review works focus mainly on the different materials available that can be used as phase-change materials. Conversely, this review encloses, classifies and describes the results of different works found in the literature that studied individual solutions to enhance the performance of systems combining heat pumps and latent heat thermal energy storage.acceptedVersio

Análisis teórico-experimental del comportamiento de una bomba de calor con sistema de captación híbrido geotérmico-aerotérmico

La climatización y producción de ACS mediante bombas de calor está experimentando un importante desarrollo, tanto a nivel tecnológico como de implantación debido a la necesidad de sistemas cada vez más eficientes. Estos sistemas se basan en el aprovechamiento del calor existente en un medio (tierra, agua o aire) para transferirlo al lugar a climatizar, siendo los sistemas que emplean el aire ambiente (aerotermia) y el calor existente bajo la superficie terrestre (geotermia) los que mayor nivel de implantación han alcanzado. Si bien la solución más habitual pasa por el empleo de alguna de estas dos tecnologías de modo independiente, actualmente se están comercializando equipos que combinan ambos sistemas, de modo que se consiguen aprovechar las ventajas particulares de cada uno de ellos, como son el menor coste del captador aerotérmico frente al geotérmico, el aprovechamiento de periodos con elevadas temperaturas del aire ambiente o la posibilidad de funcionamiento aun en casos con riesgo de congelación del terreno. Teniendo en cuenta la escasa información sobre este tipo de equipos, se ha llevado a cabo un estudio teórico-experimental con el que pretende alcanzar una mejor compresión sobre el funcionamiento de este tipo de sistemas, obteniendo mapas de funcionamiento que permitan establecer el sistema de captación óptimo en función de las condiciones ambientales. Para ello se ha construido un banco de ensayos que ha permitido estudiar el comportamiento de una bomba de calor comercial acoplada a un aerotermo, a un sistema que simula los pozos geotérmicos o a ambos elementos en serie

Efecto del cambio de refrigerante en un sistema de producción de hielo líquido con generador de tipo rascador

El hielo líquido es un fluido secundario con un elevado potencial debido a su alta densidad de energía gracias al aprovechamiento del calor latente de cambio de fase de microcristales de hielo en una disolución acuosa, lo que permite su bombeo sin necesidad de equipos especiales. Hasta día de hoy, se han planteado muy distintos sistemas de generación de hielo líquido, de los cuales los generadores de superficie rascada son los que mayor nivel de implantación comercial han alcanzado. Por otra parte, las reglamentaciones existentes en referencia al uso de los refrigerantes halogenados hacen que sea necesario dar solución a aquellos sistemas que originalmente empleaban refrigerantes de tipo CFCs y HCFCs. En este trabajo, se analiza experimentalmente el efecto de la sustitución directa de R22 por R417A en un equipo de generación de hielo líquido con generador de superficie rascada. En el artículo, se describe el equipo experimental utilizado, se detalla la metodología experimental seguida y se presentan y analizan los principales resultados obtenidos

Optimización del dimensionado del sistema de captación de una bomba de calor geotérmica según la zona climática

Las bombas de calor geotérmicas pueden implicar ahorros energéticos importantes en comparación con sistemas de climatización clásicos, gracias al aprovechamiento del terreno, cuyas temperaturas son muy estables a lo largo del año, como foco térmico. El tamaño de los sistemas de captación va a influir notablemente en la eficiencia de las bombas de calor, por lo que es fundamental obtener una solución de compromiso entre las prestaciones de las bombas de calor y la inversión necesaria. Este artículo parte de un trabajo previo en el que se estudió el comportamiento de una bomba de calor geotérmica con inversión de ciclo al variar la superficie de intercambio (el número de pozos activos) del sistema de captación. Basándose en los datos experimentales obtenidos en dicho trabajo, y teniendo en cuenta los costes de este tipo de instalaciones, se ha realizado un análisis económico de la instalación, para analizar el impacto que tiene el número de perforaciones y la superficie de intercambio en el coste de la instalación y en el ahorro obtenido debido al aumento de la eficiencia, con el objetivo de alcanzar un dimensionado óptimo. Este análisis se ha realizado teniendo en cuenta las condiciones climáticas de capitales de provincia representativas de las zonas climáticas definidas según el Apéndice B de la Sección HE 1 del Documento Básico HE del Código Técnico de la Edificación. Se han obtenido diferentes soluciones y tiempos de retorno de la inversión según las condiciones ambientales consideradas

MobyDeep: A lightweight CNN architecture to configure models for text classification

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGNowadays, trends in deep learning for text classification are addressed to create complex models to deal with huge datasets. Deeper models are usually based on cutting edge neural network architectures, achieving good results in general but demanding better hardware than shallow ones. In this work, a new Convolutional Neural Network (CNN) architecture (MobyDeep) for text classification tasks is proposed. Designed as a configurable tool, resultant models (MobyNets) are able to manage big corpora sizes under low computational costs. To achieve those milestones, the architecture was conceived to produce lightweight models, having their internal layers based on a new proposed convolutional block. That block was designed and customized by adapting ideas from image to text processing, helping to squeezing model sizes and to reduce computational costs. The architecture was also designed as a residual network, covering complex functions by extending models up to 28 layers. Moreover, middle layers were optimized by residual connections, helping to remove fully connected layers on top and resulting in Fully CNN. Corpus were chosen from the recent literature, aiming to define real scenarios when comparing configured MobyDeep models with other state-of the-art works. Thus, three models were configured in 8, 16 and 28 layers respectively, offering competitive accuracy results

Preproghrelin expression is a key target for insulin action on adipogenesis.

This study aimed to investigate the role of preproghrelin-derived peptides in adipogenesis. Immunocytochemical analysis of 3T3-L1 adipocyte cells showed stronger preproghrelin expression compared with that observed in 3T3-L1 preadipocyte cells. Insulin promoted this expression throughout adipogenesis identifying mTORC1 as a critical downstream substrate for this profile. The role of preproghrelin-derived peptides on the differentiation process was supported by preproghrelin knockdown experiments, which revealed its contribution to adipogenesis. Neutralization of endogenous O-acyl ghrelin (acylated ghrelin), unacylated ghrelin, and obestatin by specific antibodies supported their adipogenic potential. Furthermore, a parallel increase in the expression of ghrelin-associated enzymatic machinery, prohormone convertase 1/3 (PC1/3) and membrane-bound O-acyltransferase 4 (MBOAT4), was dependent on the expression of preproghrelin in the course of insulin-induced adipogenesis. The coexpression of preproghrelin system and their receptors, GHSR1a and GPR39, during adipogenesis supports an autocrine/paracrine role for these peptides. Preproghrelin, PC1/3, and MBOAT4 exhibited dissimilar expression depending on the white fat depot, revealing their regulation in a positive energy balance situation in mice. The results underscore a key role for preproghrelin-derived peptides on adipogenesis through an autocrine/paracrine mechanism

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Hepatic levels of S-adenosylmethionine regulate the adaptive response to fasting

26 p.-6 fig.-1 tab.-1 graph. abst.There has been an intense focus to uncover the molecular mechanisms by which fasting triggers the adaptive cellular responses in the major organs of the body. Here, we show that in mice, hepatic S-adenosylmethionine (SAMe)—the principal methyl donor—acts as a metabolic sensor of nutrition to fine-tune the catabolic-fasting response by modulating phosphatidylethanolamine N-methyltransferase (PEMT) activity, endoplasmic reticulum-mitochondria contacts, β-oxidation, and ATP production in the liver, together with FGF21-mediated lipolysis and thermogenesis in adipose tissues. Notably, we show that glucagon induces the expression of the hepatic SAMe-synthesizing enzyme methionine adenosyltransferase α1 (MAT1A), which translocates to mitochondria-associated membranes. This leads to the production of this metabolite at these sites, which acts as a brake to prevent excessive β-oxidation and mitochondrial ATP synthesis and thereby endoplasmic reticulum stress and liver injury. This work provides important insights into the previously undescribed function of SAMe as a new arm of the metabolic adaptation to fasting.M.V.-R. is supported by Proyecto PID2020-119486RB-100 (funded by MCIN/AEI/10.13039/501100011033), Gilead Sciences International Research Scholars Program in Liver Disease, Acción Estratégica Ciberehd Emergentes 2018 (ISCIII), Fundación BBVA, HORIZON-TMA-MSCA-Doctoral Networks 2021 (101073094), and Redes de Investigación 2022 (RED2022-134485-T). M.L.M.-C. is supported by La CAIXA Foundation (LCF/PR/HP17/52190004), Proyecto PID2020-117116RB-I00 (funded by MCIN/AEI/10.13039/501100011033), Ayudas Fundación BBVA a equipos de investigación científica (Umbrella 2018), and AECC Scientific Foundation (Rare Cancers 2017). A.W. is supported by RTI2018-097503-B-I00 and PID2021-127169OB-I00, (funded by MCIN/AEI/10.13039/501100011033) and by “ERDF A way of making Europe,” Xunta de Galicia (Ayudas PRO-ERC), Fundación Mutua Madrileña, and European Community’s H2020 Framework Programme (ERC Consolidator grant no. 865157 and MSCA Doctoral Networks 2021 no. 101073094). C.M. is supported by CIBERNED. P.A. is supported by Ayudas para apoyar grupos de investigación del sistema Universitario Vasco (IT1476-22), PID2021-124425OB-I00 (funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe,” MCI/UE/ISCiii [PMP21/00080], and UPV/EHU [COLAB20/01]). M.F. and M.G.B. are supported by PID2019-105739GB-I00 and PID2020-115472GB-I00, respectively (funded by MCIN/AEI/10.13039/501100011033). M.G.B. is supported by Xunta de Galicia (ED431C 2019/013). C.A., T.L.-D., and J.B.-V. are recipients of pre-doctoral fellowships from Xunta de Galicia (ED481A-2020/046, ED481A-2018/042, and ED481A 2021/244, respectively). T.C.D. is supported by Fundación Científica AECC. A.T.-R. is a recipient of a pre-doctoral fellowship from Fundación Científica AECC. S.V.A. and C.R. are recipients of Margarita Salas postdoc grants under the “Plan de Recuperación Transformación” program funded by the Spanish Ministry of Universities with European Union’s NextGeneration EU funds (2021/PER/00020 and MU-21-UP2021-03071902373A, respectively). T.C.D., A.S.-R., and M.T.-C. are recipients of Ayuda RYC2020-029316-I, PRE2019/088960, and BES-2016/078493, respectively, supported by MCIN/AEI/10.13039/501100011033 and by El FSE invierte en tu futuro. S.L.-O. is a recipient of a pre-doctoral fellowship from the Departamento de Educación del Gobierno Vasco (PRE_2018_1_0372). P.A.-G. is recipient of a FPU pre-doctoral fellowship from the Ministry of Education (FPU19/02704). CIC bioGUNE is supported by Ayuda CEX2021-001136-S financiada por MCIN/AEI/10.13039/501100011033. A.B.-C. was funded by predoctoral contract PFIS (FI19/00240) from Instituto de Salud Carlos III (ISCIII) co-funded by Fondo Social Europeo (FSE), and A.D.-L. was funded by contract Juan Rodés (JR17/00016) from ISCIII. A.B.-C. is a Miguel Servet researcher (CPII22/00008) from ISCIII.Peer reviewe

State-of-the-Art for the use of Phase-Change Materials in Tanks Coupled with Heat Pumps

With the goal of increasing heat storage in the same accumulation volumes, phase-change materials are considered. There are different substances with different phase-change temperatures that can be used for storing heating or cooling implemented in heat pump systems for applications of space heating and cooling, ventilation or domestic hot water production. Reducing the size of the buffer tanks used with heat pumps, avoiding the oversizing of heat pumps or detaching thermal energy production and consumption are among the benefits that could result from the combination of heat pumps and latent heat thermal energy storage. In addition, this form of thermal energy storage allows enhancing the use of renewable energy sources as heat sources for heat pump systems. Most previous review works focus mainly on the different materials available that can be used as phase-change materials. Conversely, this review encloses, classifies and describes the results of different works found in the literature that studied individual solutions to enhance the performance of systems combining heat pumps and latent heat thermal energy storage.Accepted Versio