Center for Materials and Microsystems

Sol-gel routes were used to prepare pure and 5 at% and 10 at% Ta- or Nb-dope TiO2 nano-sized powders. The thermal decomposition behaviour of the precursors was studied using simultaneous thermogravimetric and differential thermal analysis (TG/DTA). X-ray diffraction (XRD) analysis showed that the powders heated to 400°C were crystalline in the anatase TiO2 structure. The pure TiO2 powder heated to 850°C showed the rutile structure. The addition of Ta and Nb inhibited the anatase-to-rutile phase transformation up to 950–1050°C. Ta was soluble in the titania lattice up to the concentration of 10 at%, while the solubility of Nb was 5 at%. Thick films were fabricated with these powders by screen printing technology and then fired for 1 h at different temperatures in the 650–1050°C range. Scanning electron microscopy (SEM) observations showed that the anatase-to-rutile phase transformation induces a grain growth of about one order of magnitude for pure TiO2. The addition of Ta and Nb is effective to keep the TiO2 grain size at a nanometric level even at 950°C, though grain growth was observed with increasing temperature. The gas-sensitive electrical response of the thick films were tested in laboratory, in environments with CO in dry and wet air. Conductance measurements showed a good gas response only for the nanostructured titania-based films. For field tests, the prototype sensors were placed beside a conventional station for atmospheric pollutant monitoring. The electrical response of the thick films was compared with the results of the analytical instruments. The same trend was observed for both systems, demonstrating the use of gas sensors for this aim.

Thick-®lm gas sensors were fabricated by screen-printing technology starting from different nanostructured semiconducting oxide powders both n-type and p-type; ultra®ne and homogeneously sized ceramic powders were prepared using chemical methods such as sol± gel techniques and thermal decomposition of heteronuclear complexes. The temporal evolution of the conductivity changes in the various semiconducting oxide thick ®lms were studied in comparison with the concentrations of CO, NO, NO 2 and O 3 in the atmosphere as measured by the analytical equipment. An air quality control experiment in an urban area through some arrays of nanostructured thick-®lm sensors without an in situ calibration is described. Through the calibration performed directly in the ®eld, one of the monitoring units by means of the conventional equipment, it was possible to evaluate the pollutants' concentration in various points of the city. The good results obtained with this experiment allow us to consider the feasible use of the innovative station to measure the pollution due to the automotive traf®c. #

Chemical routes such as sol-gel techniques and thermal decomposition of heteronuclear complexes have been used to prepare Ž . Ž . nanosized powders of n-type SnO , TiO and In O and p-type LaFeO semiconducting oxides. Thick film gas sensors have been 2 2 2 3 3 fabricated using these powders, printed on laser pre-cut 96% alumina substrates, each 2 = 2 mm element being provided with a heater, Au interdigitated contacts and a Pt-100 resistor for controlling the operating temperature. The films have been fired at different temperatures Ž . suitable to keep the grain size at the nanometer level. Electrical responses to some major polluting gases CO, NO, NO and O obtained 2 3 in the field have been compared with international standard analytical techniques. q 2000 Elsevier Science S.A. All rights reserved.

The present work describes the realization of a modular 1-3 kWe, 3-9 kWth micro Combined Heat and Power (m-CHP) system based on innovative Concentrated Solar Power (CSP) and Stirling engine technology. The cogeneration of energy at distributed level is one of leading argument in large part of energy policies related to renewable energy resources and systems. This CSP m-CHP will provide electrical power, heating and cooling for single and multiple domestic dwellings and other small buildings.

Regions of Central Europe are characterised by the economic activity mainly performed by micro companies and small and medium sized enterprises (SMEs). In accordance with the sustainable economic development of the Central Europe SMEs, key objectives have been recognised to tackle the challenge, namely: implementation of energy efficient and environmentally friendly technologies in production process, promotion of economic and social benefits of sustainability and achieving positive changes in behaviour of employees. This paper presents a novel approach (3EMT tool) for sustainability assessment of SMEs together with resulting normalized quantitative indicators, statistical benchmark indicators and SME energy consumption profiles. The 3EMT tool enables the evaluation of energy and environmental performance of SMEs and provides ranking useful for benchmarking and supports regional sustainability evaluation.

This paper is a novel presentation of the way by which different innovative technologies have been integrated to realize a complete energy sustainability for the home. The FBK-REET unit has developed a hybrid and integrated technology able to provide electrical and thermal energy for heating, cooling and sanitary water. The energy system is based on renewable sources as the solar energy and biomass. The solar radiation will be converted through solar thermal collectors into thermal energy and photovoltaic modules into electrical energy. A biomass boiler will cogenerate electrical and thermal power by the integration of a Stirling engine. An energy storage system, based on micro porous zeoliteslike material and adsorption and desorption reactions, will be integrated in the system and will provide mainly cooling on the hot season. The integrated approach has excluded problems such as stagnation temperatures on solar collectors, it has limited the request of energy from the grids (natural gas and electricity) and it has increased the overall efficiency of the system.

Energy plays a key factor in the advancement of humanity. As energy demands are mostly met by fossil fuels, the worldwide consciousness grows about their negative impact on the environment. Therefore, it becomes necessary to design sustainable energy systems by introducing renewable energies. Because of the intermittent availability of different renewable resources, the designing of a sustainable energy system should find an optimal mix of different resources. However, the optimization of this combination has to deal with a number of possibly contradictory objectives. Multi-objective evolutionary algorithms (MOEA) are widely used to solve this kind of problems. As optimizing an energy system by using a MOEA is computationally costly, it is necessary to solve the problem efficiently. For this purpose, we propose the incorporation of domain knowledge related to energy systems into different phases (i.e., initialization and mutation) of a MOEA run. The proposed approaches are implemented for two widely used MOEAs and evaluated on the Danish Aalborg test problem. The experimental results show that each approach individually achieves significant improvements of the energy systems, which is expressed in better trade-off sets. Moreover, a state-of-theart stopping criterion is adapted to detect the convergence in order to save

We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a 'hands-on' approach, providing practical details and procedures as derived from literature as well as from the authors' experience, in order to enable the reader to reproduce the results. 2D Mater. 7 (2020) 022001 C Backes et al be used to probe morphological properties, as well as to study growth mechanisms and quality of transfer. More generally, SPM combined with smart measurement protocols in various modes allows one to get obtain information on mechanical properties, surface potential, work functions, electrical properties, or effectiveness of functionalization. Some of the techniques described are suitable for 'in situ' characterization, and can be hosted within the growth chambers. If the diagnosis is made 'ex situ', consideration should be given to the preparation of the samples to avoid contamination. Occasionally cleaning methods have to be used prior to measurement. I. Bottom-up I.1. Graphene nanoribbons I.2. Graphene and carbon nanomembranes I.3. Heterostructures from CNMs II. Top-down II.1. Precursors II.2. Liquid phase exfoliation II.3. GO and RGO II.4. Chemical intercalation and reductive exfoliation II.5. Electrochemical exfoliation II.6. Sonication-assisted versus chemical versus electrochemical exfoliation II.7. Computational modelling of exfoliation of LMs III. Processing of dispersions III.1. Size selection III.2. Inks formulation III.3. Printing and deposition of inks III.4. Applications IV. Graphene growth on SiC IV.1. Sublimation IV.2. CVD growth on SiC V. CVD, PVD & MBE V.1. Growth on metals V.2. Graphene growth on semiconductors V.3. Graphene growth on insulators V.4. Brief comparison of all methods VI. Graphene transfer, placement and decoupling from substrate VI.1. Wet transfer VI.2. Semi-dry transfer: hot press lamination and UV assisted transfer VI.3. Dry transfer using h-BN VI.4. Graphene/PMMA sandwich structures VII. Growth and transfer of other layered materials VII.1. Hexagonal BN VII.2. Layered semiconductors VII.3. Layered materials heterostructures VIII. Functionalization of GRMs VIII.1. Covalent functionalization of graphene VIII.2. Functionalization of GO VIII.3. Noncovalent functionalization of graphene VIII.4. Defect functionalization of GRM VIII.5. Decoration with nanoparticles VIII.6. Functionalization of other LMs IX. Characterization methods IX.1. Microscopies IX.2. Spectroscopies IX.3. Electrical characterization IX.4. Mechanical characterization Conclusions Acknowledgment References

We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a 'hands-on' approach, providing practical details and procedures as derived from literature as well as from the authors' experience, in order to enable the reader to reproduce the results. 2D Mater. 7 (2020) 022001 C Backes et al be used to probe morphological properties, as well as to study growth mechanisms and quality of transfer. More generally, SPM combined with smart measurement protocols in various modes allows one to get obtain information on mechanical properties, surface potential, work functions, electrical properties, or effectiveness of functionalization. Some of the techniques described are suitable for 'in situ' characterization, and can be hosted within the growth chambers. If the diagnosis is made 'ex situ', consideration should be given to the preparation of the samples to avoid contamination. Occasionally cleaning methods have to be used prior to measurement. I. Bottom-up I.1. Graphene nanoribbons I.2. Graphene and carbon nanomembranes I.3. Heterostructures from CNMs II. Top-down II.1. Precursors II.2. Liquid phase exfoliation II.3. GO and RGO II.4. Chemical intercalation and reductive exfoliation II.5. Electrochemical exfoliation II.6. Sonication-assisted versus chemical versus electrochemical exfoliation II.7. Computational modelling of exfoliation of LMs III. Processing of dispersions III.1. Size selection III.2. Inks formulation III.3. Printing and deposition of inks III.4. Applications IV. Graphene growth on SiC IV.1. Sublimation IV.2. CVD growth on SiC V. CVD, PVD & MBE V.1. Growth on metals V.2. Graphene growth on semiconductors V.3. Graphene growth on insulators V.4. Brief comparison of all methods VI. Graphene transfer, placement and decoupling from substrate VI.1. Wet transfer VI.2. Semi-dry transfer: hot press lamination and UV assisted transfer VI.3. Dry transfer using h-BN VI.4. Graphene/PMMA sandwich structures VII. Growth and transfer of other layered materials VII.1. Hexagonal BN VII.2. Layered semiconductors VII.3. Layered materials heterostructures VIII. Functionalization of GRMs VIII.1. Covalent functionalization of graphene VIII.2. Functionalization of GO VIII.3. Noncovalent functionalization of graphene VIII.4. Defect functionalization of GRM VIII.5. Decoration with nanoparticles VIII.6. Functionalization of other LMs IX. Characterization methods IX.1. Microscopies IX.2. Spectroscopies IX.3. Electrical characterization IX.4. Mechanical characterization Conclusions Acknowledgment References

Solar thermal technologies are already available on the market, and they are robust and relatively cheap. Unfortunately, solar heat is seldom used in the industrial processes, and the main obstacle of solar heat diffusion is often the lack of adequate predictive modelling of solar plant integration that identifies its energy potential, economic feasibility, and environmental benefits. In this paper, we aim to investigate and evaluate the possibility of supplying solar heat to the pasta-drying process located in the northeast of the Italian Alps (“Felicetti”). The methodology proposed is structured with the combination of several software, namely, PVGIS®, Matlab®, Dymola®. The methodology developed is tested, considering solar thermal energy as the primary source, in different geographical contexts.

The solar receiver is a critical component of concentrated solar power technology; it works as a heat exchanger, transforming the concentrated solar radiation into high-temperature heat. Volumetric receiver technologies, using air as a heat transfer fluid, are designed to reach higher temperatures than the current receiver technology, which is limited by material resistance and fluid instability. The higher temperature, up to 1200 K, could be used in high-temperature industrial processes or a high-temperature thermodynamic cycle. A correct radiation propagation is essential to develop their performances, reducing reflection and emission losses and promote the heat transfer to the fluid. In this study, the optical behaviour of a hierarchical volumetric receiver (HVR) developed in Bruno Kessler Foundation (FBK) has been studied using Monte Carlo ray tracing (MCRT) simulations. The simulations have been validated in an experimental setup that evaluates the light transmissivity of the H...

Solar driven cooling machines have been employed until recent years only in niche markets due to a series of reasons: dimensions of the machines, cooling power storage, production costs, and others. At present times there's a high request for a reliable technology developed for domestic applications at distributed level. The solar heating is a rapidly growing market and the available technologies are almost consolidated, but a strong limitation to the application of solar collectors is due to the waste heat available in summer periods, which limit the sizing of solar domestic installations, limit the capacity to provide not only support to hot sanitary water, but even to indoor space heating. The objective of the present work is to suggest a possible solution and try to give a contribution to the described problem. The R&D performed at FBK-REET labs has produced a new concept of solar driven cooling/heating machine based on a double adsorption/desorption cycle acting between two...

Regions of Central Europe are characterised by the economic activity mainly performed by micro companies and small and medium sized enterprises (SMEs). In accordance with the sustainable economic development of the Central Europe SMEs, key objectives have been recognised to tackle the challenge, namely: implementation of energy efficient and environmentally friendly technologies in production process, promotion of economic and social benefits of sustainability and achieving positive changes in behaviour of employees. This paper presents a novel approach (3EMT tool) for sustainability assessment of SMEs together with resulting normalized quantitative indicators, statistical benchmark indicators and SME energy consumption profiles. The 3EMT tool enables the evaluation of energy and environmental performance of SMEs and provides ranking useful for benchmarking and supports regional sustainability evaluation.

The distributed cogeneration of energy is one of the leading arguments for the improvement of renewable energy share in the energy consumption at European level. The actual work describe the realization of a modular 1-3 kWe, 3-9 kWth micro Combined Heat and Power (m-CHP) system based on innovative Concentrated Solar Power (CSP) and Stirling engine technology. This CSP m-CHP will provide electrical power, heating and cooling for single and multiple domestic dwellings and other small buildings. It integrates small scale concentrator optics with moving and tracking components, solar absorbers in the form of evacuated tube collectors, a heat transfer fluid properly investigated, a Stirling engine with generator after the development and testing of two main solutions, and heating and/or cooling systems; it incorporates them into buildings in an architecturally acceptable manner, with low visual impact. The work is part of a European Funded project (DiGeSPo) in the CALL ENERGY-2009-1.

A concentrated solar power (CSP) biomass combined heat and power (CHP) system based on organic Rankine cycle (ORC) technology developed in the framework of the EU founded BRICKER project is presented. The CHP system coupled with heat recovery ventilation technology and novel insulation material has the aim of reducing the energy consumption of existing building by up to 50%. A simplified approach to implement a dynamic model of the CHP system is proposed. The model is firstly used to investigate the performances of the CHP system control logic under extreme working condition. Secondly, the effectiveness in ensuring safe working conditions and in maximizing the sun power usage of two different solar field control approaches is investigated simulating the developed model over a reference day.

A new sustainable technology has been designed by Fondazione Bruno Kessler through its unit Renewable Energies and Environmental Technologies. This technology is realized integrating in a single system (1) a Stirling engine (mRT-1K) from a pre-engineering design of Allan J. Organ; (2) a micro-heat exchanger technology, to reduce the net transfer unit deficit on the hot side of the heat engine; (3) a customized pellet boiler, able to extract electrical and thermal power; and (4) a customized hydraulic circuit, connecting the cool side of the Stirling engine and the heat generation on the second section of the pellet boiler. The objective of this paper was to present a new technology for the micro-cogeneration of energy at a distributed level able to be integrated in domestic dwellings. Most part of the available biomass is used in buildings for the generation of thermal power for indoor heating and, in minor cases, for hot sanitary water. In the Province of Trento, 88% of the biomass is used for this purpose. The full system is actually under integration for the test phase and not yet tested. The first tests on the single components have confirmed preliminary results on the Stirling engine with respect to the tolerances, pressurization, and proper integration of the electrical generator-driven control system. The pellet boiler has been tested separately, confirming an overall thermal efficiency of 90%.

The present work describes the realization of a modular 1-3 kWe, 3-9 kWth micro Combined Heat and Power (m-CHP) system based on innovative Concentrated Solar Power (CSP) and Stirling engine technology. The cogeneration of energy at distributed level is one of leading argument in large part of energy policies related to renewable energy resources and systems. This CSP m-CHP will provide electrical power, heating and cooling for single and multiple domestic dwellings and other small buildings. The developed system integrates small-scale concentrator optics with moving and tracking components, solar absorbers in the form of evacuated tube collectors, a heat transfer fluid, a Stirling engine with generator, and heating and/or cooling systems; it incorporates them into buildings in an architecturally acceptable manner, with low visual impact. Some good results have already been achieved, while developments on several technology subcomponents will be finalized through first part of 2013. Two Cer.Met. have been modelled, realized and tested. The up scaled receiver, in form of Cer.Met. coating based on TiO2-Nb, has been confirmed an absorptance of 0.94 and emittance of 0.1 (@350°C). A second Cer.Met. coating based on SiO2-W has demonstrated an absorptance of 0.93 and emittance of Luigi Crema et al. / Energy Procedia 57 (2014) 447-456 0.09 (@350°C). A full-evacuated solar tube has been designed and realized, with absorber of 12 mm in diameter and length in 2 meters. The system is provided of a concentration ratio 12:1, and a single module is 200 cm long, 40 cm wide and 20-25 cm high. Two or more modules can be combined. The evacuated solar tube, located on the focus, has the selective absorber on a tube of 12 mm in diameter. A very thin glass mirror has been developed (< 1 mm). The overall mirror reflectivity has been measured, the verified value is 0,954. Research has proposed a high energy density, double acting Stirling engine, provided of innovative heat exchangers realized through Selective Laser Melting process. The engine is a low speed (250 RPM), high pressure (130 Bars) and compact solution able to be run at 300°C and generate 3,5 kW nominal power. The solar technology has actually entered the proof-of-concept stage. A solar plant has been installed in Malta, by Arrow Pharm company, supplying the industrial process of generated steam at 180°C and 3.5 absolute pressure. The solar collector's efficiency is close to 47% in presence of 900 W/m2 of direct solar radiation. During 2013, solar evacuated tubes with innovative Cer.Met. coating, together with new thin glass mirrors will upgrade the demonstration site, together with a new and innovative low temperature difference and high energy density Stirling. By end-2013, the system will be demonstrated, with the overall objective to achieve a minimum of 65% in solar collectors' efficiency at 300°C, and 12-15% of overall electrical efficiency by the Stirling cycle. The actual work is part of a FP7 European Funded project, DIGESPO [1].