Study of the tightness of the metallization used on top of a thin film capacitor cell

Dissertação de mestrado integrado em Engenharia de Materiais

Experimental and numerical studies of hybrid PCM embedded in plastering mortar for enhanced thermal behaviour of buildings

This paper proposes a methodology for improvement of energy efficiency in buildings through the innovative simultaneous incorporation of three distinct phase change materials (here termed as hybrid PCM) in plastering mortars for façade walls. The thermal performance of a hybrid PCM mortar was experimentally evaluated by comparing the behaviour of a prototype test cell (including hybrid PCM plastering mortar) subjected to realistic daily temperature profiles, with the behaviour of a similar prototype test cell, in which no PCM was added. A numerical simulation model was employed (using ANSYS-FLUENT) to validate the capacity of simulating temperature evolution within the prototype containing hybrid PCM, as well as to understand the contribution of hybrid PCM to energy efficiency. Incorporation of hybrid PCM into plastering mortars was found to have the potential to significantly reduce heating/cooling temperature demands for maintaining the interior temperature within comfort levels when compared to normal mortars (without PCM), or even mortars comprising a single type of PCM.

Estufa de aproveitamento solar térmico para reabilitação de edifícios

Dissertação de mestrado em sustentabilidade do ambiente construido

The design and development of heat extraction technologies for the utilisation of compost thermal energy

A composting Heat Extraction Unit (HEU) was designed to utilise waste heat from decaying organic matter for a variety of heating application The aim was to construct an insulated small scale, sealed, organic matter filled container. In this vessel a process fluid within embedded pipes would absorb thermal energy from the hot compost and transport it to an external heat exchanger. Experiments were conducted on the constituent parts and the final design comprised of a 2046 litre container insulated with polyurethane foam and kingspan with two arrays of qualpex piping embedded in the compost to extract heat. The thermal energy was used in horticultural trials by heating polytunnels using a radiator system during a winter/spring period. The compost derived energy was compared with conventional and renewable energy in the form of an electric fan heater and solar panel. The compost derived energy was able to raise polytunnel temperatures to 2-3°C above the control, with the solar panel contributing no thermal energy during the winter trial and the electric heater the most efficient maintaining temperature at its preset temperature of 10°C. Plants that were cultivated as performance indicators showed no significant difference in growth rates between the heat sources. A follow on experiment conducted using special growing mats for distributing compost thermal energy directly under the plants (Radish, Cabbage, Spinach and Lettuce) displayed more successful growth patterns than those in the control. The compost HEU was also used for more traditional space heating and hot water heating applications. A test space was successfully heated over two trials with varying insulation levels. Maximum internal temperature increases of 7°C and 13°C were recorded for building U-values of 1.6 and 0.53 W/m2K respectively using the HEU. The HEU successfully heated a 60 litre hot water cylinder for 32 days with maximum water temperature increases of 36.5°C recorded. Total energy recovered from the 435 Kg of compost within the HEU during the polytunnel growth trial was 76 kWh which is 3 kWh/day for the 25 days when the HEU was activated. With a mean coefficient of performance level of 6.8 calculated for the HEU the technology is energy efficient. Therefore the compost HEU developed here could be a useful renewable energy technology particularly for small scale rural dwellers and growers with access to significant quantities of organic matter

Potentially viable solar powered appliances cooling and distillation

Stand alone solar powered refrigeration and water desalination, two of the most popular and sought after applications of solar energy systems, have been selected as the topic of research for the works presented in this thesis. The water desalination system based on evaporation and condensation was found to be the most suitable one to be powered by solar energy. It has been established that highoutput fast-response solar heat collectors used to achieve high rates of evaporation and reliable solar powered cooling system for faster rates of condensation are the most important factors in achieving increased outputs in solar powered desalination systems. Comprehensive reviews of Solar powered cooling/refrigeration and also water desalination techniques have been presented. In view of the fact that the Institute of Technology, Sligo has a well-established long history of research and development in the production of state of the art high-efficiency fast-response evacuated solar heat collectors it was decided to use this know how in the work described in this thesis. For this reason achieving high rates of evaporation was not a problem. It was, therefore, the question of the solar powered refrigeration that was envisaged to be used in the solar powered desalination tofacilitate rapid condensation of the evaporated water that had to be addressed first. The principles of various solar powered refrigeration techniques have also been reviewed. The first step in work on solar powered refrigeration was to successfully modify a conventional refrigerator working on Platen-Munters design to be powered by highoutput fast-response evacuated solar heat collectors. In this work, which was the first ever successful attempt in the field, temperatures as low as —19°C were achieved in the icebox. A new approach in the use of photovoltaic technology to power a conventional domestic refrigerator was also attempted. This was done by modifying a conventional domestic refrigerator to be powered by photovoltaic panels in the most efficient way. In the system developed and successfully tested in this approach, the power demand has been reduced phenomenally and it is possible to achieve 48 hours of cooling power with exposure to just 7 hours of sunshine. The successful development of the first ever multi-cycle intermittent solar powered icemaker is without doubt the most exciting breakthrough in the work described in this thesis. Output of 74.3kg of ice per module with total exposure area of 2.88 m2, or 25.73kg per m2, per day is a major improvement in comparison to about 5-6kg of ice per m2 per day reported for all the single cycle intermittent systems. This system has then become the basis for the development of a new solar powered refrigeration system with even higher output, named the “composite” system described in this thesis. Another major breakthrough associated with the works described in this thesis is the successful development and testing of the high-output water desalination system. This system that uses a combination of the high-output fast-response evacuated solar heat collectors and the multi-cycle icemaker. The system is capable of producing a maximum of 141 litres of distilled water per day per module which has an exposure area of 3.24m2, or a production rate of 43.5 litres per m2 per day. Once again when this result is compared to the reported daily output of 5 litres of desalinated water per m per day the significance of this piece of work becomes apparent. In the presentation of many of the components and systems described in this thesis CAD parametric solid modelling has been used instead of photographs to illustrate them more clearly. The multi-cycle icemaker and the high-output desalination systems are the subject of two patent applications.

L'energia solar fotovoltaica com una alternativa en els espais urbans

Estudi realitzat per avaluar la possibilitat i viabilitat d’instal·lació de panells solar fotovoltaics als terrats de les comunitats de veïns del Districte de l’Eixample de Barcelona. La seva finalitat és conscienciar a la població sobre la problemàtica actual del canvi climàtic fent ús de la ciutat com a element clau per a fomentar l’estalvi de consum energètic i la reducció d’emissions de diòxid de carboni (CO2). Els resultats obtinguts ens donen un valor aproximat de la superfície i potència necessària pels habitants de la ciutat de Barcelona i Catalunya, per tal de cobrir el seu consum d’electricitat d’ús domèstic amb energia solar fotovoltaica, així com una comparativa amb els resultats obtinguts en el Districte de l’Eixample en les dimensions: socio-econòmica, mediambiental i política.

Numerical simulation of combined heat transfer phenomena (conduction, convection, and radiation). Application to he optimisation of thermal systems

Thermal systems interchanging heat and mass by conduction, convection, radiation (solar and thermal ) occur in many engineering applications like energy storage by solar collectors, window glazing in buildings, refrigeration of plastic moulds, air handling units etc. Often these thermal systems are composed of various elements for example a building with wall, windows, rooms, etc. It would be of particular interest to have a modular thermal system which is formed by connecting different modules for the elements, flexibility to use and change models for individual elements, add or remove elements without changing the entire code. A numerical approach to handle the heat transfer and fluid flow in such systems helps in saving the full scale experiment time, cost and also aids optimisation of parameters of the system. In subsequent sections are presented a short summary of the work done until now on the orientation of the thesis in the field of numerical methods for heat transfer and fluid flow applications, the work in process and the future work.

The tectonically controlled emplacement of a vertically sheeted gabbro-pyroxenite intrusion: Feeder-zone of an ocean-island volcano (Fuerteventura, Canary Islands)

The Miocene PX1 gabbro-pyroxenite pluton, Fuerteventura, Canary Islands, is a 3.5 x 5.5 km shallow-level intrusion (0.15-0.2 GPa and 1100-1120 degrees C), interpreted as the feeder-zone to an ocean-island volcano. It displays a vertical magmatic banding expressed in five 50 to 100 metre-wide NNE-SSW trending alkaline gabbro sequences alternating with pyroxenites. This emplacement geometry was controlled by brittle to ductile shear zones, generated by a regional E-W extensional tectonic setting that affected Fuerteventura during the Miocene. At a smaller scale, the PX1 gabbro and pyroxenite bands consist of metre-thick differentiation units, which suggest emplacement by periodic injection of magma pulses as vertical dykes that amalgamated, similarly to a sub-volcanic sheeted dyke complex. Individual dykes underwent internal differentiation following a solidification front parallel to the dyke edges. This solidification front may have been favoured by a significant lateral/horizontal thermal gradient, expressed by the vertical banding in the gabbros, the fractionation asymmetry within individual dykes and the migmatisation of the wall rocks. Pyroxenitic layers result from the fractionation and accumulation of clinopyroxene +/- olivine +/- plagioclase crystals from a mildly alkaline basaltic liquid. They are interpreted as truncated differentiation sequences, from which residual melts were extracted at various stages of their chemical evolution by subsequent dyke intrusions, either next to or within the crystallising unit. Compaction and squeezing of the crystal mush is ascribed to the incoming and inflating magma pulses. The expelled interstitial liquid was likely collected and erupted along with the magma flowing through the newly injected dykes. Clinopyroxene mineral orientation - as evidenced by EBSD and micro X-ray tomography investigations - displays a marked pure-shear component, supporting the interpretation of the role of compaction in the generation of the pyroxenites. Conversely, gabbro sequences underwent minor melt extraction and are believed to represent crystallised coalesced magma batches emplaced at lower rates at the end of eruptive cycles. Clinopyroxene orientations in gabbros record a simple shear component suggesting syn-magmatic deformation parallel to observed NNE-SSW trending shear zones induced by the regional tensional stress field. This emplacement model implies a crystallisation time of 1 to 5 years for individual dykes, consistent with PX1 emplacement over less than 0.5 My. A minimum amount of approximately 150 km(3) of magma is needed to generate the pluton, part of it having been erupted through the Central Volcanic Centre of Fuerteventura. If the regional extensional tectonic regime controls the PX1 feeder-zone initiation and overall geometry, rates and volumes of magma depend on other, source-related factors. High injection rates are likely to induce intrusion growth rates larger than could be accommodated by the regional extension. In this case, dyke intrusion by propagation of a weak tip, combined with the inability of magma to circulate through previously emplaced and crystallised dykes could result in an increase of non-lithostatic pressure on previously emplaced mushy dyke walls; thus generating strong pure-shear compaction within the pluton feeder-zone and interstitial melt expulsion. These compaction-dominated processes are recorded by the cumulitic pyroxenite bands. (C) 2010 Elsevier B.V. All rights reserved.

L'energia solar fotovoltaica

Treball de recerca realitzat per alumnes d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit cientí­fic del Jovent l'any 2009. Després d'una breu introducció sobre l'energia solar, l'estudi analitza quin és el procés de fabricació que se segueix per fer les plaques solars fotovoltaiques policristal·lines i monocristal·lines i quin és el seu funcionament. És a dir, com és possible obtenir energia elèctrica gràcies a la llum del Sol. També es descriuen les instal·lacions autònomes i les connectades a la xarxa, així com els elements que les integren. S'inclou, a més, un punt explicant quins són els factors que condicionen l'obtenció d'energia i els avenços més recents en aquest camp de la tecnologia. Per finalitzar la part teòrica, s'analitza una instal·lació fotovoltaica situada a Cervera i la seva producció. Pel que fa al treball de camp, es va construir un seguidor solar.

L'energia solar a Cerdanyola del Vallès

Treball de recerca realitzat per alumnes d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit cientí­fic del Jovent l'any 2009. Aquest treball intenta resoldre la qüestió de si l'energia solar arribarà a ser una energia alternativa que esdevingui un substitut del petroli en el futur. Aquest projecte informa de totes les característiques i propietats de les plaques solars, explicant els avantatges que fan que sigui un recurs energètic molt net, segur i, encara que en un principi es pugui veure car, finalment arriba a amortitzar el preu inicial fins aconseguir un estalvi monetari, que és el que atreu al màxim de compradors. El projecte parla de les característiques de les plaques solars fotovoltaiques explicant així tots els materials pels quals és formada, la seva estructura per capes i el procés de transformació de llum en electricitat. Conté, també, una part pràctica extensa i elaborada: s'ha demanat a diversos ciutadans, sobretot de Cerdanyola del Vallès i també de Barcelona, sobre el tipus de contacte que tenen amb aquesta energia renovable i si no és així, saber quin altre tipus de font energètica utilitzen. També conté una entrevista a un professional del món de l'energia solar. I, finalment, s'ha realitzat el disseny, muntatge i funcionament d'un cotxe elèctric solar.

Cap a l'autosuficiència energètica: barri La Plana, Sitges

En el present estudi s’ha analitzat si és possible l’autosuficiència energètica al barri projectat de La Plana de Sitges a partir de fonts renovables d’energia. S’ha realitzat un anàlisi de l’oferta potencial del barri de La Plana, format per habitatges unifamiliars i plurifamiliars, serveis i equipaments i s’ha comparat el potencial de producció energètica dels recursos renovables locals a cada subsistema i pel sistema de La Plana. Diferenciant si són una Oferta estàndard (4.000 MWh/a) seguint la Normativa d’ecoeficiència de Sitges o bé una Oferta renovable (19.000 MWh/a) segons un Ecobarri proposat en aquest projecte a partir d’energia solar fotovoltaica i tèrmica. En l’estudi de la demanda, diferenciant entre una Demanda estàndard (39.000 MWh/a), respon al total de La Plana seguint el consum d’un habitatge tipus de la mitjana catalana (ICAEN, 2002) i una Demanda eficient (20.800 MWh/a) seguint un model de baix consum projectat en un Ecobarri de Barcelona. (Vallbona, 2009). Per analitzar de forma detallada les variables d’oferta i demanda, s’han proposat quatre escenaris diferents on es valoren l’autosuficiència energètica del sistema de la Plana i aspectes ambientals d’emissions derivades de la utilització de l’energia. El primer escenari és l’estàndard i és el resultat d’analitzar conjuntament una oferta i una demanda estàndard. Al segon escenari conflueixen una Oferta Estàndard i una Demanda Eficient. En el tercer escenari coincideixen una Oferta Renovable i una Demanda Estàndard. El quart i últim escenari respon a la proposta d’Ecobarri on l’Oferta és renovable i la Demanda eficient. Tanmateix, s’ha realitzat un estudi sobre els aspectes econòmics de La Plana que s’estimen en uns beneficis per la venda de l’energia d’uns 5 milions d’euros anuals i uns costos d’instal·lació de 80 milions d’euros. Finalment s’ha constatat que és possible assolir una autosuficiència del 90% a l’escenari Ecobarri (oferta renovable - demanda eficient). Mitjançant la instal·lació de sistemes de captació solar a les cobertes, cobrint el 100% de la demanda d’ACS, i captadors solars FV, ambdues estratègies són viables i representen beneficis econòmics i una reducció d’emissions de l’ordre de 13.700 Tn CO2 equivalents anuals que suposen un estalvi del 88% respecte un escenari d’oferta i demanda estàndard.

Plasma membrane cyclic nucleotide gated calcium channels control land plant thermal sensing and acquired thermotolerance.

Typically at dawn on a hot summer day, land plants need precise molecular thermometers to sense harmless increments in the ambient temperature to induce a timely heat shock response (HSR) and accumulate protective heat shock proteins in anticipation of harmful temperatures at mid-day. Here, we found that the cyclic nucleotide gated calcium channel (CNGC) CNGCb gene from Physcomitrella patens and its Arabidopsis thaliana ortholog CNGC2, encode a component of cyclic nucleotide gated Ca(2+) channels that act as the primary thermosensors of land plant cells. Disruption of CNGCb or CNGC2 produced a hyper-thermosensitive phenotype, giving rise to an HSR and acquired thermotolerance at significantly milder heat-priming treatments than in wild-type plants. In an aequorin-expressing moss, CNGCb loss-of-function caused a hyper-thermoresponsive Ca(2+) influx and altered Ca(2+) signaling. Patch clamp recordings on moss protoplasts showed the presence of three distinct thermoresponsive Ca(2+) channels in wild-type cells. Deletion of CNGCb led to a total absence of one and increased the open probability of the remaining two thermoresponsive Ca(2+) channels. Thus, CNGC2 and CNGCb are expected to form heteromeric Ca(2+) channels with other related CNGCs. These channels in the plasma membrane respond to increments in the ambient temperature by triggering an optimal HSR, leading to the onset of plant acquired thermotolerance.

Anàlisi i disseny d'un programari de Gestió Remota d'un Parc Modular d'Energia Solar

Anàlisi i disseny d'una aplicació per gestionar de manera remota l'activitat d'un parc d'energia solar fotovoltaica.

Effects of highly active antiretroviral therapy with nelfinavir in vertically HIV-1 infected children: 3 years of follow-up. Long-term response to nelfinavir in children.

BACKGROUND Antiretroviral treatment (ART) in children has special features and consequently, results obtained from clinical trials with antiretroviral drugs in adults may not be representative of children. Nelfinavir (NFV) is an HIV-1 Protease Inhibitor (PI) which has become as one of the first choices of PI for ART in children. We studied during a 3-year follow-up period the effects of highly active antiretroviral therapy with nelfinavir in vertically HIV-1 infected children. METHODS Forty-two vertically HIV-infected children on HAART with NFV were involved in a multicentre prospective study. The children were monitored at least every 3 months with physical examinations, and blood sample collection to measure viral load (VL) and CD4+ cell count. We performed a logistic regression analysis to determinate the odds ratio of baseline characteristics on therapeutic failure. RESULTS Very important increase in CD4+ was observed and VL decreased quickly and it remained low during the follow-up study. Children with CD4+ <25% at baseline achieved CD4+ >25% at 9 months of follow-up. HIV-infected children who achieved undetectable viral load (uVL) were less than 40% in each visit during follow-up. Nevertheless, HIV-infected children with VL >5000 copies/ml were less than 50% during the follow-up study. Only baseline VL was an important factor to predict VL control during follow-up. Virological failure at defined end-point was confirmed in 30/42 patients. Along the whole of follow-up, 16/42 children stopped HAART with NFV. Baseline characteristics were not associated with therapeutic change. CONCLUSION NFV is a safe drug with a good profile and able to achieve an adequate response in children.

Estudi d’integració d’energia tèrmica i fotovoltaica a façana

L’objecte d’aquest projecte és realitzar un estudi d’un tipus instal·lacions molt específiques: l’energia solar fotovoltaica i l’energia solar tèrmica, destinada a la producció d’energia elèctrica i la producció d’ACS a un edifici plurifamiliar. Aplicar un cas concret a un edifici plurifamiliar, mitjançant d’integració dels panells fotovoltaics i tèrmics a la façana, i així, poder conformar la instal•lació d’energiasolar tèrmica per la producció d’aigua calenta sanitària i la instal·lació d’energia solar fotovoltaica. Comprovar si es possible complir CTE, mitjançant l’ integració arquitectònica dels panells a façana. Determinar el cost que suposa d’integració arquitectònica d’aquest panells, mitjançant el pressupost de la proposta a portada . Comparar el cost de la proposta, amb una façana tradicional més els panells solars tèrmics que exigeix el codi tècnic. Extreure conclusions al comparar les tipologies de façana a nivell econòmic i de rendibilitat