José Sánchez Ramos

Aroche (Huelva, Andalucía): a new Neolithic axehead of Alpine jade in the southwest of the Iberian Peninsula

The discovery of a Neolithic Alpine jade axehead in Aroche, in the southwest of Spain, revives the question of long-distance exchange between the Iberian Peninsula and the rest of Europe. This polished blade belongs to a typological model quite characteristic of Alpine production during the second half of the 5th millennium B.C. Different mineralogical approaches (macroscopic features examination, specific gravity, direct XRD, non-destructive μXRF spectroscopy, optical stereomicroscopy, magnetic susceptibility determination and microprobe analysis) have identified the rock as an omphacitic jadeitite (mixed jade) with some tiny garnets and a weak retromorphosis. This analysis and the comparison of the rock structure with the referential JADE of Alpine natural jade samples, as well as the extraction modalities and shaping of the axe, provide strong arguments to assign the Aroche axe to a production of Mont Viso: the origin of thousands of axes that circulated in Europe between Ireland and Sicily. The Aroche axe, discovered not far from the variscite mines of Encinasola, could be considered as part of a possible exchange system between the Iberian Peninsula and the Gulf of Morbihan, in Brittany.

INFLUENCIA DEL CAUDAL DE VENTILACIÓN E INFILTRACIÓN SOBRE LA DEMANDA ENERGÉTICA EN EDIFICIOS RESIDENCIALES EN ESPAÑA

Este trabajo tiene como objetivo calcular de forma detallada los caudales de ventilacion e infiltracion y analizar su influencia sobre la demanda energetica de edificios con uso residencial en Espana. Actualmente el Codigo Tecnico de la Edificacion (CTE) es la normativa espanola que regula los criterios de diseno, calculo y la ejecucion de las instalaciones de ventilacion. Los actuales criterios para el calculo de caudales de ventilacion estan condicionados por criterios de salubridad del aire interior. Sin embargo, no tienen en cuenta la infiltracion por permeabilidad de la fachada o la zona geografica de viento donde se encuentre el edificio. Estos criterios influyen de manera determinante sobre las demandas de acondicionamiento. La metodologia empleada tiene en cuenta el calculo de caudales de ventilacion e infiltracion hora a hora, permitiendo estudiar la influencia de variables como la permeabilidad de las fachadas (definidas en la EN 15242:2007), y la velocidad del viento exterior, sobre los caudales de ventilacion. Ademas, se estudia de forma cuantitativa la influencia de estos caudales sobre las demandas de acondicionamiento. El estudio se realiza en tres zonas climaticas espanolas (Cadiz, Madrid y Zaragoza), donde cambian sustancialmente las velocidades de viento exterior y la severidad climatica. El resultado de este trabajo demuestra la importancia de estas variables sobre las demandas de acondicionamiento, sobre todo en calefaccion, encontrando diferencias de hasta un 14% en funcion de la zona de viento y la permeabilidad de la fachada del edificio. Palabras Clave: Ventilacion, Infiltracion, Caudal de ventilacion, Demanda de ventilacion, Calidad de aire interior.

ME3A: Software tool for the identification of energy saving measures in existing buildings: Automated identification of saving measures for buildings using measured energy consumptions

At present, actions for the rehabilitation of cities, districts and buildings are being promoted for tertiary as well as for residential buildings. However, the difficulty of assessing the energy savings achieved after energy efficiency improvement measures (or even worse, a combination of them which have cross effects) with enough certainty is well known. The tendency in order to solve this issue is the use of buildings energy performance simulation tools, either detailed or simplified. Nevertheless, the estimation of the energy consumption made by these tools differs from the measured values, due to either the case definition or the assumptions taken into account. This publication aims to present a solution for both of the above mentioned problems, by using a simulation tool which has been corrected with climatic and consumption measured data. This tool has been developed within the framework of the project ME3A-Energy Efficiency Improvement of Buildings in Andalusia (2014–2016), funded by the Regional Government of Andalusia. The main development work is the correction of the simulation tool using consumption data counters monitored in the building, so this development is tested in three building and this paper shows the results of one of them. The benefits presented by this tool are the result of the previously carried out research, which was focused on the automated generation of baselines through which the estimated energy situation made by the official tool and the real measurement can be corrected. These baselines are stated in terms of the main energetic parameters that define a building. In this way, they are converted into a diagnostic protocol with which energetic indicators and the expected reference values can be compared. This methodology shows as a result the optimal rehabilitation project in economic and energetic terms. It is worth mentioning that the developed tool is integrated as a complement within the existing methodology of energy certification (CE3). Therefore, apart from drawing data from the building definition and its systems (performed by the official tool), it allows to obtain the modified official certificate once the optimal rehabilitation project has been chosen.

Ventilación natural: estudio aerodinámico mediante CFD de extractores pasivos y captadores de viento

La ventilacion natural se ha ganado protagonismo en los ultimos tiempos como una medida de ahorro de energia para edificios. Los dos principios fundamentales de ventilacion natural son el tiro natural por diferencia de temperatura, y la fuerza del viento. El articulo pretende analizar la aerodinamica de los captadores y extractores de viento mediante fluido-mecanica computacional, optimizando las geometrias de estos elementos, y dando como producto del trabajo un modelo simplificado para poder tenerlos en cuenta el calculo aeraulico de las instalaciones de ventilacion y climatizacion de los edificios. Concretamente, se caracteriza una base de geometrias de captacion de viento, y se elabora una guia para el diseno de geometrias de extraccion ofreciendo varias de ellas como producto del trabajo realizado.In recent years, natural ventilation has won popularity as an energy saving measure for buildings. There are two fundamental principles of natural ventilation: natural draft by temperature differences, and wind force. The purpose of the article is to analyze the aerodynamics of windcatchers and wind-extractors by means of computational fluid mechanics, optimizing the geometries of these elements, and giving a simplified model as a result of the work, so as to include it in the aeraulic calculation of the buildings’ air conditioning systems. Therefore, a base for wind catching geometries has been characterized, and a guide for the design of extraction geometries has been developed; several of them are offered as a result of the work undertaken.