Dissertationen zum Thema „Indoor photovoltaics“

The evolution of the internet of things (IoT) opens the market opportunity for organic photovoltaic cells, especially for indoor applications where the lifetime of the organic cells is longer than outdoor. For example, IoT requires off-grid energy sources for many devices with low power consumption. In this work, new materials were tested as candidate components in the active layer of printed organic photovoltaics by fabrication of devices. The initial electrical performance of these devices and their stability over time were investigated by measurements of the current-voltage characteristics. Three selected active layers were further investigated with atomic force microscopy (AFM) measurements. The current-voltage measurements showed that the addition of a solvent additive to the active layer ink affects the initial electrical performance as well as the stability of the devices. The AFM measurements showed that the surface topography of the active layer was affected by the sort of solvent additive that was used. Three new electron acceptor material and two solvent additives showed promising electrical performance and stability.

Les cellules solaires organiques (OSC) à hétérojonction en volume (BHJ) semblent être des candidates idéales pour alimenter les appareils de l'Internet des objets (IoT) en conditions intérieures en raison de leur compatibilité avec les technologies d'impression à faible coût, leur flexibilité, et leur efficacité de conversion de puissance élevée (PCE) sous faible illumination. De plus, l'adaptabilité des matériaux organiques permet de moduler précisément leurs propriétés optiques et électroniques pour que leur absorption corresponde idéalement aux spectres d’émission des sources d’éclairage de type LED. Cependant, des améliorations supplémentaires de l'efficacité et de la stabilité sont nécessaires pour exploiter leur potentiel. Dans cette thèse, nous avons étudié plusieurs stratégies liées aux matériaux de couches actives pour améliorer les performances des OSC en conditions indoor. Le premier objectif était d’intégrer de nouveaux accepteurs non fullerènes (NFA), notamment à base d'heptazines, pour mieux exploiter la région bleue (400-500 nm) de l’émission des LED blanches, qui reste mal adressées à ce jour. Des dérivés d'heptazine innovants ont été étudiés et intégrés dans les couches actives des OSC dans ce contexte. Bien que des propriétés optiques et morphologiques appropriées aient été observées, ainsi qu’une séparation de charge prometteuse entre les matériaux donneurs et accepteurs, des limitations spécifiques de performance, telles qu’une faible génération de photocourant, ont été mises en évidence. Néanmoins, ce travail jette les bases d'une optimisation supplémentaire des NFA à base d'heptazine pour les applications OSC en intérieur. La deuxième orientation de recherche s'est concentrée sur l'optimisation de la couche active OSC à base du mélange PF2:ITIC, utilisé pour la première en intérieur.. À cette fin, nous avons exploité plusieurs paramètres cruciaux tels que la sélection du solvant, l'épaisseur de la couche active et le rapport donneur/accepteur (D:A). Grâce à des techniques spécifiques de caractérisation en champ proche, nous avons identifié le chlorobenzène (CB) comme le solvant le plus efficace pour traiter le mélange PF2:ITIC, produisant des couches actives lisses et uniformes avec d'excellentes caractéristiques morphologiques. L'augmentation de l'épaisseur de la couche active de 100 nm à 270 nm a considérablement amélioré l'absorption de la lumière dans la région bleue, ce qui a entraîné un photocourant plus élevé, permettant ainsi de démontrer des dispositifs atteignant un PCE allant jusqu'à 11,95 % avec un VOC élevé de 0,73 V sous un éclairage LED chaud à 1000 lux. Ce travail démontre finalement l'importance d'une conception moléculaire innovante et de l'optimisation du système pour améliorer les performances des OSC pour les applications intérieures
Organic solar cells (OSCs) based on a bulk-heterojunction (BHJ) concept are emerging as ideal candidates for powering indoor Internet-of-things (IoT) devices due to their compatibility with low-cost printing technologies, flexible substrates, and high power conversion efficiency (PCE) under indoor lighting. Additionally, the tunability of organic materials allows for precise adjustments in their optical and electronic properties to ideally match the emission spectra of indoor sources such as LEDs. This adaptability makes OSCs particularly promising for indoor environments. However, further improvements in efficiency and stability are needed to exploit their potential. In this thesis, several strategies were explored to improve OSC performance for indoor applications. The first focus was on the integration of novel non-fullerene acceptors (NFAs), especially heptazine-based, to better address the blue region (400-500 nm) of white LED emission, which remains a specific challenge. Innovative Heptazine derivatives were studied and integrated into OSC active layers in this context. Although suitable optical and morphological properties were observed, as well as promising charge separation between donor and acceptor materials, specific limitations in performance, such as low photocurrent generation, were evidenced. Nevertheless, this work lays the foundation for further optimization of heptazine-based NFAs for indoor OSC applications. The second research direction focused on optimizing the PF2:ITIC-based OSC active layer for indoor applications. To this end, we explore several crucial parameters, such as solvent selection, active layer thickness, and donor-to-acceptor (D:A) ratio. Thanks to specific near-field characterization techniques, we identified chlorobenzene (CB) as the most effective solvent to process the PF2:ITIC blend, producing smooth, uniform active layers with excellent morphological features. Increasing the active layer thickness from 100 nm to 270 nm significantly improved light absorption in the blue region, resulting in a higher photocurrent, enabling the demonstration of devices achieving PCE up to 11.95% with a high VOC of 0.73 V under warm LED illumination at 1000 lux. Finally, this work demonstrates the crucial importance of innovative molecular design and system optimization in improving the performance of OSCs for indoor applications

The alleviation of heating (in winter), cooling (in summer), artificial lighting and electricity use in office facilities is defined as a bioclimatic trend that offers sustainable building practice through a semi-transparent building integrated photovoltaic thermal envelope as a photovoltaic airflow window system. This thesis aims to produce synthesised design and strategies for the use of a proposed airflow window unit in office building in any given location and to maximise use of the renewable energy. Computational Fluid Dynamics (CFD), namely ANSYS Fluent 14.0, and ECOTECT have been employed to model the mechanical and natural ventilation of an office building integrated with a semi-transparent photovoltaic airflow window and the daylighting impact of various PV transparent degrees (15, 20, 25, 30 and 35 per cent) on the interior space, respectively, for winter and summer conditions. The use of such software has urged to establish a validation analysis a priori in order to ascertain the applicability of the tools to the targeted examination. The validation process involved a comparison of the results of CFD turbulence models, first, against benchmark and, second, against results of literature for identical component. The results of ECOTECT, in terms of daylight factor and illuminance level, were also compared against the results of Daysim/radiance, Troplux and BC/LC found in the literature. Excellent agreement was attained from the comparison of the results with errors less than 10 per cent. The study presents results of modelling of the airflow window system integrated into an office room for energy efficiency and adequate level of thermal and visual comfort. Results have revealed that the combination of mechanical and buoyancy induced flow spreads the heat internally warming the space to be thermally acceptable during the heating season whilst the mechanical convection is a main force for the cooling season. The thermal and visual comfort was compared for different PV airflow window transparent levels to determine the optimum PV transparency for the office space. Moreover, time-dependant and steady state conditions were imposed to predict the thermal and air behaviour for more elaborate investigation. The transient analysis was carried out, in sequential and individual base, according to the solar irradiance of each minute of working period, 8am-4pm (winter) and 5am-7pm (summer). The results obtained from transient and steady state, for both seasons, were compared and revealed negligible impact of transient effect. The PV electricity output was calculated from each transparency level under each condition, summer and winter (transient and steady). The predicted flow patterns, temperature distribution and the daylight factors in the room have been used to determine the most appropriate opening locations, sizes and system specifications for maintaining a comfortable indoor environment. The simulation investigation show that, for the proposed window model, optimum thermal and visual performance can be achieved from the PV transparency level of 20 per cent, during the heating season, and from the PV transmittance of 15 per cent, during the cooling season, where the PV output is highest. However the PV transparencies of 25, 30 and 35% can be reliable under altered conditions of operation.

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de Computadores
This research thesis presents a micro-power light energy harvesting system for indoor environments. Light energy is collected by amorphous silicon photovoltaic (a-Si:H PV) cells, processed by a switched-capacitor (SC) voltage doubler circuit with maximum power point tracking (MPPT), and finally stored in a large capacitor. The MPPT Fractional Open Circuit Voltage (VOC) technique is implemented by an asynchronous state machine (ASM) that creates and, dynamically, adjusts the clock frequency of the step-up SC circuit, matching the input impedance of the SC circuit to the maximum power point (MPP) condition of the PV cells. The ASM has a separate local power supply to make it robust against load variations. In order to reduce the area occupied by the SC circuit, while maintaining an acceptable efficiency value, the SC circuit uses MOSFET capacitors with a charge reusing scheme for the bottom plate parasitic capacitors. The circuit occupies an area of 0.31 mm2 in a 130 nm CMOS technology. The system was designed in order to work under realistic indoor light intensities. Experimental results show that the proposed system, using PV cells with an area of 14 cm2, is capable of starting-up from a 0 V condition, with an irradiance of only 0.32 W/m2. After starting-up, the system requires an irradiance of only 0.18 W/m2 (18 mW/cm2) to remain in operation. The ASM circuit can operate correctly using a local power supply voltage of 453 mV, dissipating only 0.085 mW. These values are, to the best of the authors’ knowledge, the lowest reported in the literature. The maximum efficiency of the SC converter is 70.3% for an input power of 48 mW, which is comparable with reported values from circuits operating at similar power levels.
Portuguese Foundation for Science and Technology (FCT/MCTES), under project PEst-OE/EEI/UI0066/2011, and to the CTS multiannual funding, through the PIDDAC Program funds. I am also very grateful for the grant SFRH/PROTEC/67683/2010, financially supported by the IPL – Instituto Politécnico de Lisboa.

Les systèmes photovoltaïques organiques sont des technologies émergentes présentant de forts potentiels d’économie de ressources et de réduction des impacts sur l'environnement et la santé humaine par rapport aux dispositifs photovoltaïques conventionnels. La méthode de l’analyse du cycle de vie est appliquée afin d'évaluer la façon dont les différents procédés de fabrication, les caractéristiques des dispositifs, la phase d’utilisation et les scénarios de fin de vie des cellules photovoltaïques organiques influent sur ces avantages potentiels. Les impacts de cette technologie émergente sont comparés aux technologies conventionnelles à base de silicium pour établir un référentiel de performance des technologies photovoltaïques.En outre, les effets potentiels sur la santé humaine de l'utilisation de nanomatériaux dans les cellules photovoltaïques organiques ont été spécifiquement étudiés ; et la pertinence de l’analyse du cycle de vie pour évaluer cette catégorie d’impact a été examinée. Ainsi, un nouveau modèle d'évaluation de l'impact sur le cycle de vie est présenté afin de quantifier les dangers potentiels posés par les nanomatériaux. Enfin,ces impacts potentiels sont comparés aux avantages des cellules photovoltaïques organiques sur les cellules à base de silicium
Organic photovoltaics present an emerging technology with significant potential for increasing the resource efficiencies and reducing the environmental and human health hazards of photovoltaic devices. The discipline of life-cycle assessment is applied to assess how various prospective manufacturing routes, device characteristics, uses and disposal options of organic photovoltaics influences these potential advantages. The results of this assessment are further compared to silicon based photovoltaics as a benchmark for performance. A deeper look is given to the potential human health impacts of the use of engineered nanomaterials in organic photovoltaics and the appropriateness of life-cycle assessment to evaluate this impact criteria. A newly developed life-cycle impact assessment model is presented to demonstrate whether the use of and potential hazards posed by engineered nanomaterials outweighs any of the resource efficiencies and advantages organic photovoltaics possess over silicon photovoltaics

"O presente trabalho estuda um sistema de conversão de energia fotovoltaica para aplicações em ambientes interiores. O sistema é composto por uma célula fotovoltaica, um conversor de corrente contínua para corrente contínua de capacidades comutadas e um elemento de armazenamento de energia. É frequente que um sistema de recolha de energia fotovoltaica se baseie num método que permita que a máxima potência seja extraída da célula. Porém esses métodos não garantem que a máxima potência seja entregue à carga, perdendo-se no conversor. É igualmente importante garantir que se transfere a máxima potência. Assim o sistema proposto visa não só garantir que a máxima potência é recolhida, mas também que a máxima potência é guardada no dispositivo de armazenamento. O nível de condicionamento de energia é composto por um charge pump duplicador de tensão e um circuito de arranque entre a célula fotovoltaica e o conversor. Garantindo assim que o charge pump apenas opera quando a energia disponível é suficiente para o seu correto funcionamento. A saída é ligada a um super condensador, onde é armazenada energia. Foram feitas diversas simulações para estudar a performance do sistema."
"The present work aims to study a photovoltaic (PV) energy conversion system for indoor applications. This system consists of a PV cell, a DC-DC switched capacitor (SC) and an energy storage element. It is common to PV harvesting systems to use maximum power point tracking (MPPT) methods in order to extract the maximum power from the PV cell. However, these methods do not guarantee the maximum power is delivered to the load, being lost in the DC-DC SC. It is important to also guarantee the maximum power point is transferred. Thus this system aims to guarantee the maximum power is being harvested but also the maximum power is being storage to the storage element. The power conditioning stage consist of cross coupled voltage doubler charge pump and a star up circuit between the PV cell and the switched capacitor. This stage guarantees the charge pump only operates when the energy available is sufficient for its correct operation. The output connects to a supercapactior where the energy is stored. Several simulations were made to analyse the performance of the system."

碩士
國立臺北大學
電機工程學系
102
This paper presents a low-voltage indoor energy harvesting using photovoltaic cell. No other external components, in addition to outside the solar panel and battery. The system doesn't use a dc to dc converter in boosting an output voltage to avoid large external inductors and large capacitance element. Then use a rechargeable battery to store energy. It eliminates the use of alkaline batteries that requires a regular replacement from time to time. This work operates at room lighting illumination of 110cm(625Lux)~350cm(61Lux) which can provide a voltage of about 0.4V~0.55V. The chip is implemented using TSMC 0.18um CMOS process with chip area of 0.85×0.85mm2 and the power consumption is 271uW. In case of supply voltage 0.5V, the maximum efficiency of 54%.

碩士
國立臺北大學
電機工程研究所
100
This paper presents light energy harvesting system with rechargeable battery used for ultra-low power devices in an indoor application. The rechargeable battery serves as a back-up supply to provide power to the load when the light source is out thereby extending the device performance to almost indefinite period. It eliminates the use of alkaline (primary) batteries that requires a regular replacement from time to time. The input voltage of the system is 500mV which is based in the typical output voltage of a 1 unit photovoltaic cell. The system does not use a dc to dc converter in boosting an output voltage to avoid complicated control algorithm and the costly implementation of inductor on the chip. This output voltage is regulated and used as a charging voltage the battery and supply voltage to the load. This work operates at room lighting illumination of 2337.93 lux which is commonly found in an industry and hospital environment. The circuit occupies a chip area of 0.962×0.935 mm2 and is fabricated using 0.18µm 1P6M process with a power dissipation of 1.25mW when delivering a load current of 395µA at 1.3V

碩士
國立交通大學
光電工程研究所
107
Conventional photovoltaic devices are designed to convert sunlight into electricity; their absorption range ideally should be wide enough to harvest long-wavelength pho-tons. In this work, we have tuned the band gap of perovskite thin films for low-power indoor applications. The band gap was slightly increased after adding Br ions in the perovskite films. Under standard one-sun illumination conditions, the perovskite photo-voltaic devices (PePVs) exhibited compared power conversion efficiencies (PCEs). However, the open-circuit voltage, film quality, and shunt resistances were improved, resulting in higher power conversion efficiencies (PCEs) under indoor lighting condi-tions. At 1000 lux, the device exhibited PCEs of 25.12% and 25.94% under illumination with light from a white light-emitting diode and a TL5 fluorescent tube, respectively. Finally, large area devices (4 cm2) were also prepared; the PCEs ranged from 15% to 18% under indoor lighting conditions.

碩士
國立交通大學
應用化學系碩博士班
100
Indolo[3,2-b]indole, containing two fused indole units, is an promising and attractive electron-rich monomer for constructing donor-acceptor materials due to its planar, symmetric, and extended conjugated structure. It is of interest to incorporate indolo[3,2-b]indole unit into a donor-acceptor ??conjugated system via its 2,7 or 3,8 positions to investigate the electronic and steric effects. In this research, we have successfully developed a new synthetic scheme to prepare 2,7-dibromo-indolo[3,2-b]indole. Unexpectedly, in an attempt to make 3,8-diromo-indolo[3,2-b]indole by following a procedure in the literature, we found that the bromination of indolo[3,2-b]indole turns out to occur at 2,7 positions rather than 3,8 positions. This finding confirms that 2,7 positions of indolo[3,2-b]indole actually possess stronger nucleophilicity to undergo electrophilic aromatic substitution reaction. 2,7-dibromoindolo[3,2-b]indole was then converted to the corresponding boronic ester monomer M1. The Suzuki coupling of M1 with monobrominated and dibrominated dithienodiketopyrrolopyrrole (DPP) led to an acceptor-donor-acceptor small molecule 2,7-bis(dithienoldiketopyrrolopyrrole)indolo[3,2-b]indole (2,7-BDPPII) and an alternating donor-acceptor copolymer PDPPII, respectively. On the other hand, M1 was also copolymerized with the benzothiadiazole (BT) unit to prepare two random copolymers PIIDTBT11 and PIIDTBT13. All the materials exhibited good thermal stabilities with the decomposition temperature ranging from 386 to 486 oC. The thin-film X-ray diffraction pattern of 2,7-BDPPII exhibited a crystalline structure. In addition, the absorption spectrum of 2,7-BDPPII in the solid state also showed red-shifted and band broadening behaviors compared to the solution state. These results indicated that highly planar structure of indolo[3,2-b]indole unit can enhance the intermolecular interaction. PDPPII showed the lower optical band gap of 1.45 eV than the small molecule 2,7-BDPPII (1.66 eV) as a result of longer conjugation length. The bulk heterojunction devices using the configuration of ITO/PEDOT:PSS/D-A material:PC71BM/Ca/Al were fabricated to evaluate these new materials. After thermal annealing at 150 oC for 7 min, the device incorporating 2,7-BDPPII as the active layer exhibited a Voc of 0.72 V, a Jsc of 6.88 mA/cm2 and a FF of 49.6%, leading to a PCE of 2.45%. This value is rather promising for small molecule-based solution processing BHJ solar cells. It is anticipated that the efficiency can be improved by further optimization of device fabrication. However, the PDPPII–based device exhibited very low performance due to the poor morphology associated with severe phase separation. The devices using PIIDTBT11 and PIIDTBT13 delivered the efficiencies of 0.65% and 0.59%, respectively.

abstract: This is a two-part thesis. Part 1 presents an approach for working towards the development of a standardized artificial soiling method for laminated photovoltaic (PV) cells or mini-modules. Construction of an artificial chamber to maintain controlled environmental conditions and components/chemicals used in artificial soil formulation is briefly explained. Both poly-Si mini-modules and a single cell mono-Si coupons were soiled and characterization tests such as I-V, reflectance and quantum efficiency (QE) were carried out on both soiled, and cleaned coupons. From the results obtained, poly-Si mini-modules proved to be a good measure of soil uniformity, as any non-uniformity present would not result in a smooth curve during I-V measurements. The challenges faced while executing reflectance and QE characterization tests on poly-Si due to smaller size cells was eliminated on the mono-Si coupons with large cells to obtain highly repeatable measurements. This study indicates that the reflectance measurements between 600-700 nm wavelengths can be used as a direct measure of soil density on the modules. Part 2 determines the most dominant failure modes of field aged PV modules using experimental data obtained in the field and statistical analysis, FMECA (Failure Mode, Effect, and Criticality Analysis). The failure and degradation modes of about 744 poly-Si glass/polymer frameless modules fielded for 18 years under the cold-dry climate of New York was evaluated. Defect chart, degradation rates (both string and module levels) and safety map were generated using the field measured data. A statistical reliability tool, FMECA that uses Risk Priority Number (RPN) is used to determine the dominant failure or degradation modes in the strings and modules by means of ranking and prioritizing the modes. This study on PV power plants considers all the failure and degradation modes from both safety and performance perspectives. The indoor and outdoor soiling studies were jointly performed by two Masters Students, Sravanthi Boppana and Vidyashree Rajasekar. This thesis presents the indoor soiling study, whereas the other thesis presents the outdoor soiling study. Similarly, the statistical risk analyses of two power plants (model J and model JVA) were jointly performed by these two Masters students. Both power plants are located at the same cold-dry climate, but one power plant carries framed modules and the other carries frameless modules. This thesis presents the results obtained on the frameless modules.
Dissertation/Thesis
Masters Thesis Engineering 2015

碩士
國立交通大學
光電工程研究所
106
Hydrogenated amorphous silicon (a-Si:H) thin film solar cells have several advantages, including low cost, high light absorption coefficient, and low temperature process make it can be integrated with the plastic substrate For example: PET, PEN, and PI. Besides, frequency response of a-Si:H cells matches indoor light. Thus, a-Si:H cell has potential to be used f or indoor energy harvesting. The cells can be applied to “Internet of Things” and other low-power components as a power supply. In this study, a flexible a-Si:H solar cell with a n-i-p structure was fabricated on a PI substrate. A periodic light-trapping structure and an aluminum back-reflecting layer were employed in cells. High output power density of 21.92μW/cm2 is measured under T6 fluorescent tube with illumination of 600 Lux. Successfully connected two 1cm2 cells in parallel to achieve output power of 41.76 μW.. In addition, the cells can withstand 500 times bending with 3mm radius, 130℃ thermal test, and 7 hours exposure with indoor light. Connecting 14 cells with area of 1cm2 in parallel can achieve 0.56V output voltage and 518μA output current, which is sufficient to drive 3D positioning device under indoor light.

碩士
國立交通大學
電子研究所
107
This paper presents a 400-600 mV input, 900-1100 mV output fully-integrated switched-capacitor (SC) based step-up dc–dc converter with loading time extending (LTE) technique implemented in 0.18 μm CMOS technology for photovoltaic cell under indoor-light conditions. Indoor-light provides ultra-low input power which leads to ultra-low output power. Output voltage can be regulated to 1V under light-load conditions; however, there is only certain amount of time for the converter to operate above the voltage available for heavy-load output devices. The proposed LTE technique and cross-coupled based charge pumps (CCBCP) extend loading time (LT) under heavy load-current conditions. The proposed method automatically extends loading time without the need of additional capacitors or off-chip components. The experimental results show that the loading time of the proposed converter is enhanced by 50% at output load currents of 1mA. The proposed fully-integrated switched-capacitor based step-up dc–dc converter also provides 70.04% peak efficiency at output load currents of 1 μA and above 60% over the range of 0.5~2μA.

碩士
樹德科技大學
建築與環境設計研究所
99
Taiwan''s sustainable development policy and the Green Building promo-tion policy have been operating more than 10 years. At the same time, to re-duce the carbon by energy saving is the main subject in the subtropical climate zone, Taiwan. There is great irradiance quality between summer and autumn in the year. The sun source is an obvious phenomenon for the high temperature and humidity. Therefore, to maintain the building energy in the operational needs in façade design, which is the great re-search topic in the indoor thermal envi-ronment. The BIPV study is primarily on the surface of the building, which can make the energy reducing by the solar energy. An excess of sun-light will make the bright indoor space and the thermal en-vironment, which will make over loading on the air condition. Thus, the research aims the topic of the light on the BIPV modules design between the dazzles and the wall surface reflection of the sun-light in indoor environment.

碩士
國立彰化師範大學
電機工程學系
96
The paper aims to analyze the power consumption of emergency evacuation lights in the indoor-type substation. An LED emergency evacuation light system with automatic switch between utility and photovoltaic is created based on the forward-biased condition of block diode and by adopting photovoltaic as the power supply. In order to save the cost of inverters, the electricity-saving LED lights are directly connected to the system. In comparison with existing fluorescent lights in the indoor-type substations with regard to the power consumption, we can analyze the energy-saving benefit, the economic evaluation, and the reduced amount of CO2 emissions, expecting the result can be a significant reference to Taiwan Power Company when evaluating the benefit of LED emergency evacuation lights in the indoor-type substations with additional power supply of photovoltaic power system.

碩士
國立成功大學
電機工程學系
102
In recent years, wireless sensor network (WSN) technique develops rapidly, but its operation life is still limited by the energy storage element. Thus, if ambient energy is harvested to supply the sensors, the operation life can be increased and the cost can be reduced. A boost converter for indoor photovoltaic energy harvesting with low power consumption is proposed in this thesis. For harvesting energy from PV cell, the proposed converter applies the maximum power point tracking algorithm, and controls the output power of the PV cell by regulating the conduction time of the power transistors, so that the output power of the illuminance- and temperature-sensitive PV cell is utilized completely. The harvested energy is stored in a super capacitor. The proposed system is integrated into a chip, which was fabricated by using TSMC 0.18μm 1P6M mixed-signal process, and the total area is 853×1006 μm2. The best storage efficiency is 77.1 %, the best tracking efficiency is 64.8 %, and the best total efficiency is 42.8 %.

abstract: Improving the conditions of schools in many parts of the world is gradually acquiring importance. The Green School movement is an integral part of this effort since it aims at improving indoor environmental conditions. This would in turn, enhance student- learning while minimizing adverse environmental impact through energy efficiency of comfort-related HVAC and lighting systems. This research, which is a part of a larger research project, aims at evaluating different school building designs in Albania in terms of energy use and indoor thermal comfort, and identify energy efficient options of existing schools. We start by identifying three different climate zones in Albania; Coastal (Durres), Hill/Pre-mountainous (Tirana), mountainous (Korca). Next, two prototypical school building designs are identified from the existing stock. Numerous scenarios are then identified for analysis which consists of combinations of climate zone, building type, building orientation, building upgrade levels, presence of renewable energy systems (solar photovoltaic and solar water heater). The existing building layouts, initially outlined in CAD software and then imported into a detailed building energy software program (eQuest) to perform annual simulations for all scenarios. The research also predicted indoor thermal comfort conditions of the various scenarios on the premise that windows could be opened to provide natural ventilation cooling when appropriate. This study also estimated the energy generated from solar photovoltaic systems and solar water heater systems when placed on the available roof area to determine the extent to which they are able to meet the required electric loads (plug and lights) and building heating loads respectively. The results showed that there is adequate indoor comfort without the need for mechanical cooling for the three climate zones, and that only heating is needed during the winter months.
Dissertation/Thesis
Masters Thesis Architecture 2015

Dissertação de Mestrado Integrado em Engenharia do Ambiente apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
Com a crescente necessidade de recursos energéticos, é imperativo fazer uma gestão mais racional. Neste contexto, este trabalho centra-se no estudo de alternativas tecnológicas que apresentem maior eficiência do que as convencionais, tendo como caso de estudo o conjunto do complexo olímpico de piscinas de Coimbra e o centro comercial Dolce Vita de Coimbra, por forma a proporcionar uma maior saúde financeira e ambiental. É realizada uma interpretação dos consumos e custos da energia elétrica e térmica dos dois edifícios. Com esta análise a perceção das necessidades energéticas dos dois estabelecimentos ficou clara e assim foram considerados para análise energética três tipos de tecnologia que mais se adequam ao local e às necessidades conjuntas: sistema de cogeração/trigeração, coletores solares e painéis fotovoltaicos. Para o sistema cogeração/trigeração, não foi possível retirar conclusões, sendo apenas feito um enquadramento teórico e calculados os perfis de utilização. Em relação aos coletores solares e painéis fotovoltaicos, foram feitas as devidas simulações na sua aplicação ao complexo olímpico de piscinas de Coimbra, que permitem retirar as seguintes conclusões: (1) o investimento nos sistemas solares térmicos e fotovoltaicos é bastante elevado, (2) mesmo assim os dois sistemas apresentam lucro económico no final do tempo de vida (20 anos), (3) em termos energéticos, económicos e ambientais, os resultados são de um modo geral positivos nos cenários considerados.
With the growing need for energy resources, it is imperative to make a more rational management. In this context, this paper focuses on the study of technological alternatives that have higher efficiency than the conventional, taking as a case study the Olympic pool complex of Coimbra and Dolce Vita Coimbra shopping center in order to provide a greater financial and environmental health. An interpretation of the consumption and cost of electricity and thermal energy of the two buildings was made. With this analysis the perception of the energy requirements of the two establishments was clear and so was considered for energy analysis three types of technology that best suit the local and combined needs: cogeneration/trigeneration, solar collectors and photovoltaic system. For cogeneration/trigeneration system, it was not possible to draw conclusions, being only a theoretical framework and calculated profiles of use. Regarding solar collectors and photovoltaic panels, appropriate simulations were made in its application to the Olympic pool complex of Coimbra, which allow the following conclusions: (1) investment in solar thermal and photovoltaic systems is quite high, (2) still the two systems present economic profit at the end of the lifetime (20 years), (3) in terms of energy, economic and environmental, the results are relatively positive in the scenarios considered.