Estudio del potencial de calefacción y refrigeración solar térmica en edificios con tecnologías de bajo coste

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: El frío solar tuvo un gran protagonismo en la primera década del 2000, con numerosos estudios y proyectos, pero el alto coste de los sistemas solares y de las máquinas de absorción/adsorción de pequeño tamaño, hicieron que dicha tecnología no fuera viable para pequeña escala. La crisis económica del 2008 y la reducción de costes de la energía fotovoltaica acabaron casi con las nuevas instalaciones en nuestro país y también con algunos fabricantes. La tecnología avanza en todos los ámbitos, por lo que en este artículo se presenta un estudio con nuevos sistemas que ofrecen resultados con unos costes competitivos que puede hacer resurgir dicha tecnología para aplicaciones en los nuevos edificios de cero emisiones. Los últimos años han aparecido algunos modelos de concentrador solar: son escalables por unidades, de manera que se pueden instalar fácilmente, consiguiendo costes de generación inferiores a 30€/MWh (Anson y Rullan 2018), competitivos con cualquier sistema fósil y con captadores convencionales de baja temperatura. Si a este un sistema solar le añadimos una máquina de absorción o adsorción reversible de bajo coste, se puede llegar a producir calor con rendimientos similares a los sistemas tradicionales de expansión directa con condensación por aire con electricidad. Aunque los sistemas fotovoltaicos combinados con expansión directa tienen una mayor aceptación y penetración en el mercado por su simplicidad, hay varias ventajas inherentes de este sistema alternativo. El almacenamiento, un elemento indispensable en sistemas 100% renovables, tienen costes considerablemente inferiores a sistemas con baterías electroquímicas y puede llegar a marcar la diferencia. La acumulación térmica aún es mucho más económica que la eléctrica (Moià-Pol et alt 2017). Se presenta la viabilidad técnica y económica de un nuevo sistema de concentración combinada una máquina de absorción.ABSTRACT: Solar cooling had a great interest in the first decade of 2000, with several sduides and projects, but the high cost of such solar systems and their absorption machines made it impossible for small projects to be economically sustainable. The 2008 crisis and the cost reductions in fotovoltaic modules stopped nearly all projects and companies. The technology is advancing in all fields. Thus, this article presents an study with new systems that offer results with competitive costs that could put again in the market for zero emission buildings. Last years, several solar concetration units have appeared on the market: they are scalable, easy to install and they achieve Leverage Cost of Energy lower than 30€/MWh (Anson & Rullan 2018), competitive agains any fossil fuel and conventional solar collectors. If an absorption/adsorption chiller is coupled to this low cost solar system, we can produce cooling and heating with efficiencies similar to traditional air-cooled direct expansion using electricity. Even if photovoltaic systems combined with direct expansion have a higher acceptance on the market, there are several inherent advantages to these alternative systems. The energy storage, a crucial element for a 100% renewable system, has typically lower costs compared to electrochemical batteries and can make a difference at the end. Thermal storage is still cheaper than electrochemical storage.info:eu-repo/semantics/publishedVersio

Centralised and Distributed Optimization for Aggregated Flexibility Services Provision

The recent deployment of distributed battery units in prosumer premises offer new opportunities for providing aggregated flexibility services to both distribution system operators and balance responsible parties. The optimization problem presented in this paper is formulated with an objective of cost minimization which includes energy and battery degradation cost to provide flexibility services. A decomposed solution approach with the alternating direction method of multipliers (ADMM) is used instead of commonly adopted centralised optimization to reduce the computational burden and time, and then reduce scalability limitations. In this work we apply a modified version of ADMM that includes two new features with respect to the original algorithm: first, the primal variables are updated concurrently, which reduces significantly the computational cost when we have a large number of involved prosumers; second, it includes a regularization term named Proximal Jacobian (PJ) that ensures the stability of the solution. A case study is presented for optimal battery operation of 100 prosumer sites with real-life data. The proposed method finds a solution which is equivalent to the centralised optimization problem and is computed between 5 and 12 times faster. Thus, aggregators or large-scale energy communities can use this scalable algorithm to provide flexibility services.Comment: 10 pages, 7 figure

Reversion of epigenetically mediated BIM silencing overcomes chemoresistance in Burkitt lymphoma

In Burkitt lymphoma/leukemia (BL), achievement of complete remission with first-line chemotherapy remains a challenging issue, as most patients who respond remain disease-free, whereas those refractory have few options of being rescued with salvage therapies. The mechanisms underlying BL chemoresistance and how it can be circumvented remain undetermined. We previously reported the frequent inactivation of the proapoptotic BIM gene in B-cell lymphomas. Here we show that BIM epigenetic silencing by concurrent promoter hypermethylation and deacetylation occurs frequently in primary BL samples and BL-derived cell lines. Remarkably, patients with BL with hypermethylated BIM presented lower complete remission rate (24% vs 79%; P = .002) and shorter overall survival (P = .007) than those with BIM-expressing lymphomas, indicating that BIM transcriptional repression may mediate tumor chemoresistance. Accordingly, by combining in vitro and in vivo studies of human BL-xenografts grown in immunodeficient RAG2(-/-)γc(-/-) mice and of murine B220(+)IgM(+) B-cell lymphomas generated in Eμ-MYC and Eμ-MYC-BIM(+/-) transgenes, we demonstrate that lymphoma chemoresistance is dictated by BIM gene dosage and is reversible on BIM reactivation by genetic manipulation or after treatment with histone-deacetylase inhibitors. We suggest that the combination of histone-deacetylase inhibitors and high-dose chemotherapy may overcome chemoresistance, achieve durable remission, and improve survival of patients with BL

Natural History of Tuberculosis: Duration and Fatality of Untreated Pulmonary Tuberculosis in HIV Negative Patients: A Systematic Review

Background The prognosis, specifically the case fatality and duration, of untreated tuberculosis is important as many patients are not correctly diagnosed and therefore receive inadequate or no treatment. Furthermore, duration and case fatality of tuberculosis are key parameters in interpreting epidemiological data. Methodology and Principal Findings To estimate the duration and case fatality of untreated pulmonary tuberculosis in HIV negative patients we reviewed studies from the pre-chemotherapy era. Untreated smear-positive tuberculosis among HIV negative individuals has a 10-year case fatality variously reported between 53% and 86%, with a weighted mean of 70%. Ten-year case fatality of culture-positive smear-negative tuberculosis was nowhere reported directly but can be indirectly estimated to be approximately 20%. The duration of tuberculosis from onset to cure or death is approximately 3 years and appears to be similar for smear-positive and smear-negative tuberculosis. Conclusions Current models of untreated tuberculosis that assume a total duration of 2 years until self-cure or death underestimate the duration of disease by about one year, but their case fatality estimates of 70% for smear-positive and 20% for culture-positive smear-negative tuberculosis appear to be satisfactory

Neural Sliding Mode Control of a Buck-Boost Converter Applied to a Regenerative Braking System for Electric Vehicles

This paper presents the design and simulation of a neural sliding mode controller (NSMC) for a regenerative braking system in an electric vehicle (EV). The NSMC regulates the required current and voltage of the bidirectional DC-DC buck–boost converter, an element of the auxiliary energy system (AES), to improve the state of charge (SOC) of the battery of the EV. The controller is based on a recurrent high-order neural network (RHONN) trained using the extended Kalman filter (EKF) and the unscented Kalman filter (UKF) as the tools to train the neural networks to obtain a higher SOC in the battery. The performance of the controller with the two training algorithms is compared with a proportional integral (PI) controller illustrating the differences and improvements obtained with the EKF and the UKF. Furthermore, robustness tests considering Gaussian noise and varying of parameters have demonstrated the outcome of the NSMC over a PI controller. The proposed controller is a new strategy with better results than the PI controller applied to the same buck–boost converter circuit, which can be used for the main energy system (MES) efficiency in an EV architecture

Reversion of epigenetically mediated BIM silencing overcomes chemoresistance in Burkitt lymphoma

In Burkitt lymphoma/leukemia (BL), achievement of complete remission with first-line chemotherapy remains a challenging issue, as most patients who respond remain disease-free, whereas those refractory have few options of being rescued with salvage therapies. The mechanisms underlying BL chemoresistance and how it can be circumvented remain undetermined. We previously reported the frequent inactivation of the proapoptotic BIM gene in B-cell lymphomas. Here we show that BIM epigenetic silencing by concurrent promoter hypermethylation and deacetylation occurs frequently in primary BL samples and BL-derived cell lines. Remarkably, patients with BL with hypermethylated BIM presented lower complete remission rate (24% vs 79%; P = .002) and shorter overall survival (P = .007) than those with BIM-expressing lymphomas, indicating that BIM transcriptional repression may mediate tumor chemoresistance. Accordingly, by combining in vitro and in vivo studies of human BL-xenografts grown in immunodeficient RAG2(-/-)γc(-/-) mice and of murine B220(+)IgM(+) B-cell lymphomas generated in Eμ-MYC and Eμ-MYC-BIM(+/-) transgenes, we demonstrate that lymphoma chemoresistance is dictated by BIM gene dosage and is reversible on BIM reactivation by genetic manipulation or after treatment with histone-deacetylase inhibitors. We suggest that the combination of histone-deacetylase inhibitors and high-dose chemotherapy may overcome chemoresistance, achieve durable remission, and improve survival of patients with BL