El coste de la obligatoria rehabilitación energética de la vivienda colectiva: ¿un problema social?

Policy changes resulting from the adoption of the Law 8/2013 will mark a before and an after, regarding the usual ways to set out the refurbishment of the collective housing blocks. This article analyses the consequences of such changes in the field of the mandatory energy refurbishment of the residential buildings and its economical and social impact. The analysis is based on a comparative study of thirty two buildings refurbished in the last years, confronting the cost of their refurbishment with the hypothetical economic cost that such policy changes would have brought about. Results obtained show that the planned objectives will not be achieved unless an ambitious public aid policy is not turned on. Even if they are suggested in the Law, this aid is not reflected in the practice. Without them, the process will not be sustainable and the good initial intentions would turn into a social problem.Los cambios normativos derivados de la aprobación de la Ley 8/2013 de Rehabilitación, Regeneración y Renovación Urbana van a suponer un antes y un después en los habituales modos de plantear los procesos de reforma de los bloques de vivienda colectiva. El artículo analiza las consecuencias de dichos cambios en el ámbito de la obligada rehabilitación energética de edificios y su repercusión económica y social. El análisis se fundamenta en el estudio comparado de treinta y dos edificios rehabilitados en los últimos años, confrontándolos con el hipotético coste económico que la aplicación de dichos cambios hubiera supuesto en sus respectivos procesos de ejecución. Los resultados obtenidos evidencian que para alcanzar los objetivos previstos, resulta fundamental potenciar la oferta de ayudas públicas, sugeridas en la ley pero no reflejadas en la práctica, en aras de la sostenibilidad del proceso y para que las mejores intenciones no deriven en un problema social. Se justifica analíticamente la teoría escogiendo un ejemplo de la obra de Félix Candela, ejecutada por medio de cáscaras cilíndricas largas de cubierta, y elaborando el proceso de cálculo necesario propuesto

Efectos de la rehabilitación energética sobre las primeras torres residenciales de Gipuzkoa (1958-1974). Notas para los arqueólogos del futuro

After the enactment of the Land Law (1956) and during a cycle that lasted nearly 20 years, the first residential towers were constructed in Gipuzkoa, one of the territories of the Basque Autonomous Community, in Spain. As a result of the study of a series of representative cases, there is obtained that the architects of Gipuzkoa made use of them in order to test specific solutions. These solutions were characterized by the employment of diverse materials and textures that demonstrated the constructive logic of this new architectural type, providing to the façades of a special materiality. Half a century later, as a consequence of the energy refurbishment, these building envelopes are experiencing a process of coverage that expands with rapidity. The present article proceeds to analyze them before they disappear, drawing up a record of their constructive and structural characteristics, as well as their composition style.Tras la promulgación de la Ley del Suelo (1956) y durante un ciclo que habría de durar cerca de veinte años, fueron construidas las primeras torres residenciales en el territorio de Gipuzkoa. Del estudio de una serie de casos representativos, se obtiene que los arquitectos guipuzcoanos ensayaron en ellas una serie de soluciones específicas, caracterizadas por el empleo de diversos materiales y texturas que evidenciaban su lógica constructiva y dotaban a las fachadas de una especial materialidad. Medio siglo más tarde, como consecuencia de la rehabilitación energética, estas envolventes están siendo objeto de un proceso de cobertura que se expande con rapidez. El presente artículo procede a analizarlas antes de que desaparezcan complemente de nuestra vista, levantando acta de sus características constructivas, estructurales y compositivas

Antiferrodistortive phase transition in EuTiO3

X-ray diffraction, dynamical mechanical analysis and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300K the perovskite structure changes from cubic Pm-3m to tetragonal I4/mcm due to antiphase tilting of oxygen octahedra along the c axis (a0a0c- in Glazer notation). The phase transition is analogous to SrTiO3. However, some ceramics as well as single crystals of EuTiO3 show different infrared reflectivity spectra bringing evidence of a different crystal structure. In such samples electron diffraction revealed an incommensurate tetragonal structure with modulation wavevector q ~ 0.38 a*. Extra phonons in samples with modulated structure are activated in the IR spectra due to folding of the Brillouin zone. We propose that defects like Eu3+ and oxygen vacancies strongly influence the temperature of the phase transition to antiferrodistortive phase as well as the tendency to incommensurate modulation in EuTiO3.Comment: PRB, in pres

Structure and thermoelectric properties of EuTi(O,N)3 ± δ

After partial substitution of nitrogen for oxygen in EuTiO3, the crystal structure, thermoelectric properties, morphology, and electronic structure of the products were analyzed and compared with pristine EuTiO3. The space group of EuTi(O,N)3 ±  δ was orthorhombic Pnma due to the tilt and rotation of the anion octahedra, compared to cubic Pm3¯m of EuTiO3 (at room temperature). The thermoelectric properties of oxynitride polycrystalline bodies sintered in three different ways were investigated in the temperature range of 300 K < T < 950 K. The Seebeck coefficients (S) of the oxynitrides were lower compared with the oxide, and the electrical resistivities (ρ) were increased about one order of magnitude. The activation energies (E A) indicated a larger band gap of EuTi(O,N)3 ±  δ when compared to the pristine EuTiO3 (∼1.3 eV compared to 0.98 eV). A morphological characterization by transmission electron microscopy and scanning electron microscopy illustrated intrinsic nanopores within the individual particles and weak grain-interconnections indicating poor intergrain electron transport. Ab initio calculations of the electronic structures confirmed a larger band gap of the distorted crystal structure of the oxynitride and showed a decrease of the density of states at the Fermi level, explaining the reduction of the measured S