Análisis de coste óptimo de envolvente e instalaciones HVAC de un edificio bajo el nuevo CTE

El siguiente proyecto pretende adentrase en el campo de la construcción hacia el “Edificio de Consumo Casi Nulo”. La última actualización del CTE, que determina las exigencias para la construcción de los mismos, establece unos nuevos parámetros a cumplir que deberán ser estudiados y aplicados. Todo este proceso se realizará mediante la modelización de un caso de estudio ubicado en el País Vasco, más concretamente en Ermua. Se trata de un edificio de nueva construcción donde el objetivo será cumplir el estándar de edificio de consumo casi nulo mediante el aprovechamiento de los recursos tanto pasivos como activos. Todas estas mejoras se estudiarán gracias a la simulación que permite el programa Design Builder, de donde se obtendrán los diferentes parámetros que permitirán analizar cuál es la mejor relación de coste óptimo. Tras realizar la combinatoria de mejoras, se obtuvieron 179 casos. De los resultados de los mismos se puede observar la gran influencia de las ventanas como elemento clave en la pérdida de calor, siendo de vital importancia la instalación de ventanas de baja transmitancia térmica. Por otra parte, en lo que a las instalaciones de generación de calor respecta, aquellas que presentan una mayor relación de coste-consumo de energía primaria son los escenarios donde de combinan la geotermia, aerotermia o calderas de condensación con colectores solares. CastellanoHurrego proiektua kontsumo baxuko eraikinen arlo berrian barneratzea du helduru. Eraikuntzaren kode teknikoaren azken aktualizazioa, nonkontusmo baxuko eraikinen eskakizunak mugatzen dira, betebeharreko parametro berriak ezartzen ditu. Parametro hauek aztertzeko eta gero beraien aplikazioa emateko, Euskal Herrian, konkretuki Ermuan kokatuta dagoen kasu-azterketa baten bidez hedatuko da. Erakuntza hau, baliabide pasiko eta aktiboen bidez kontsumo baxuko eraikuntzaren estandarra lortzea du helburu. Prozesu hau Desing Builder-en simulazioei esker emango da, hemen parametro ezberdinak aztertuko dira, gero koste optimoaren erlazio hoberena lortzeko. Konbinazio guztiak egin eta gero, 179 kasu lortzen dira, hemenkin hainbat ondorio atera ahal daiteke, hauen artean nabargarriena transmitantzia baxuko leihoen garratzia da. Beste aldetik, bero generazioaren instalazioen artean, geotermia, aerotermia eta kondentsazio galdarak kolectore solarekin ematen den konbinazioa da koste-kontsumo erlazio hoberena ematen duena. EuskeraThe next project aims to be an introduction in the field of construction towards the NZEB. The last update of the CTE (Spanish Building Technical Code), which determines the requirements for the net-zero energy building, establishes some new parameters to be fulfilled that will have to be studied and applied. This whole process will be carried out by modelling a case study located in the Basque Country, more specifically in Ermua. For this new building the objective will be to comply with the standard of NZEB by taking advantage of both passive and active resources. All these improvements will be studied thanks to the II simulation program ‘Design Builder’, from which the different parameters will be studied and analysed in order to achieve the best cost optimal relation. After carrying out the combination of improvements, 179 cases were obtained, the main conclusion is the influence of the windows as a key element in heat loss, being the installation of low thermal transmittance window one of the best ways to achieve the NZEB standard. On the other hand, as far as the heat generation facilities are concerned, those that present a greater relation between cost and primary energy consumption are the scenarios where geothermal, aerothermal energy or condensing boilers are combined with solar collectors on the roof. Inglé

Cost-effectiveness and minimum requirements of nZEB for residential buildings under the new Spanish Technical Building Code

This paper evaluates a parametric analysis towards compliance with the nZEB standard, which in Spain is defined by the latest update of the Technical Building Code. This regulation is critically assessed regarding its ability to promote the concept of cost optimization, promote renewable energy sources and minimize primary energy consumption in the residential sector. To this end, a virtual building was defined and multiple designs were evaluated using DesignBuilder software. A set of 170 alternative scenarios was established and parametrically evaluated for five cities representing the five climatic zones of inland Spain (Bilbao, Burgos, Seville, Madrid and Almeria). The results were evaluated focusing on cost-cost effectiveness and primary energy consumption values for the different scenarios, evaluating them in relation to the minimum requirements set by the regulation. The great potential of photovoltaic energy is highlighted, which allows negative values to be obtained for the two Equivalent Uniform Annual Costs due to the cost avoided through self-consumption. This fact makes the optimal designs tend to electrification, specifically through air and ground source heat pumps. It is worth mentioning that the new Code has only established a minimum target for renewable self-consumption in the residential sector, which should be reinforced in future updates.The project leading to these results has received funding from “La Caixa” Foundation under the project code LCF/PR/SR20/52550013

Design of a Microscale Refrigeration System for Optimizing the Usable Space in Compact Refrigerators

This research aims to enter the miniature refrigeration machine sector with the objective of designing a small scale unit while maintaining a competitive coefficient of performance (COP), comparing with a Peltier plates system. To this end, a research of the current technology was carried out in order to obtain indicative values on the scales that were being worked on and their application. After the previous research, a refrigeration cycle was designed in EES (engineering equation solver). From this design, different conclusions were obtained: (1) The correct sizing of the compressor revolutions together with its displacement is crucial for the equipment to be able to provide the desired cooling capacity. (2) In order to obtain the desired cooling capacity in the microscale refrigeration system, the heat exchangers must have fins. (3) Of the analysed refrigerants, R600a is the best choice, as it shows favourable characteristics (high COP and low compression ratio) when working in this type of cycle.This work was supported by the Basque Government in the Elkartek call through the SOLRUC project “Knowledge acquisition for the design of new ultra-compact cooling solutions”, project reference: KK-2020/00115

Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

Objectives: This study aimed to assess the real use of cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) in the Spanish National Endocarditis Database (GAMES) and to compare it with antistaphylococcal penicillin (ASP). Methods: Prospective cohort study with retrospective analysis of a cohort of MSSA IE treated with cloxacillin and/or cefazolin. Outcomes assessed were relapse; intra-hospital, overall, and endocarditis-related mortality; and adverse events. Risk of renal toxicity with each treatment was evaluated separately. Results: We included 631 IE episodes caused by MSSA treated with cloxacillin and/or cefazolin. Antibiotic treatment was cloxacillin, cefazolin, or both in 537 (85%), 57 (9%), and 37 (6%) episodes, respectively. Patients treated with cefazolin had significantly higher rates of comorbidities (median Charlson Index 7, P <0.01) and previous renal failure (57.9%, P <0.01). Patients treated with cloxacillin presented higher rates of septic shock (25%, P = 0.033) and new-onset or worsening renal failure (47.3%, P = 0.024) with significantly higher rates of in-hospital mortality (38.5%, P = 0.017). One-year IE-related mortality and rate of relapses were similar between treatment groups. None of the treatments were identified as risk or protective factors. Conclusion: Our results suggest that cefazolin is a valuable option for the treatment of MSSA IE, without differences in 1-year mortality or relapses compared with cloxacillin, and might be considered equally effective