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Lollini R.,Institute for Renewable Energy | Danza L.,CNR Construction Technologies Institute | Meroni I.,CNR Construction Technologies Institute
Solar Energy | Year: 2010

The reduction of air-conditioning energy consumptions is one of the main indicators to act on when improving the energy efficiency in buildings. In the case of advanced technological buildings, a meaningful contribution to the thermal loads and the energy consumptions reduction could depend on the correct configuration and management of the envelope systems. In recent years, the architectural trend toward highly transparent all-glass buildings presents a unique challenge and opportunity to advance the market for emerging, smart, dynamic window and dimmable daylighting control technologies (Lee et al., 2004). A prototype dynamic glazing system was developed and tested at ITC-CNR; it is aimed at actively responding to the external environmental loads. Both an experimental campaign and analyses by theoretical models were carried out, aimed at evaluating the possible configurations depending on different weather conditions in several possible places. Therefore, the analytical models of the building-plant system were defined by using a dynamic energy simulation software (EnergyPlus). The variables that determine the system performance, also influenced by the boundary conditions, were analysed, such as U- and g-value; they concern both the morphology of the envelope system, such as dimensions, shading and glazing type, gap airflow thickness, in-gap airflow rate, and management, in terms of control algorithm parameters tuning fan and shading systems, as a function of the weather conditions. The configuration able to provide the best performances was finally identified by also assessing such performances, integrating the dynamic system in several building types and under different weather conditions. The dynamic envelope system prototype has become a commercial product with some applications in façade systems, curtain walls and windows. The paper describes the methodological approach to prototype development and the main results obtained, including simulations of possible applications on real buildings. © 2009 Elsevier Ltd. All rights reserved.

Marszal A.J.,University of Aalborg | Heiselberg P.,University of Aalborg | Bourrelle J.S.,Norwegian University of Science and Technology | Musall E.,University of Wuppertal | And 3 more authors.
Energy and Buildings | Year: 2011

The concept of Zero Energy Building (ZEB) has gained wide international attention during last few years and is now seen as the future target for the design of buildings. However, before being fully implemented in the national building codes and international standards, the ZEB concept requires clear and consistent definition and a commonly agreed energy calculation methodology. The most important issues that should be given special attention before developing a new ZEB definition are: (1) the metric of the balance, (2) the balancing period, (3) the type of energy use included in the balance, (4) the type of energy balance, (5) the accepted renewable energy supply options, (6) the connection to the energy infrastructure and (7) the requirements for the energy efficiency, the indoor climate and in case of gird connected ZEB for the building-grid interaction. This paper focuses on the review of the most of the existing ZEB definitions and the various approaches towards possible ZEB calculation methodologies. It presents and discusses possible answers to the abovementioned issues in order to facilitate the development of a consistent ZEB definition and a robust energy calculation methodology. © 2011 Elsevier B.V. All rights reserved.

Colli A.,Institute for Renewable Energy | Colli A.,Brookhaven National Laboratory | Zaaiman W.J.,European Commission - Joint Research Center Ispra
IEEE Journal of Photovoltaics | Year: 2012

This paper presents springtime monitoring results for different crystalline-silicon (c-Si) photovoltaic (PV) systems installed at the multitechnology ground-mounted PV test field at the Airport Bolzano Dolomiti (ABD) located in the Italian Alps. The system data are analyzed and discussed.The main purpose of this paper is to validate the performance evaluation through a methodology based on the effective maximum power of the PV modules. This approach could be useful when dealing, as in the present case, with commercial monitoring systems. Three different silicon-based technologies are taken into consideration: polycrystalline silicon, high-efficiency monocrystalline silicon, and hybrid monocrystalline silicon that have been positioned both on a single-axis tracker and on fixed 30 °-tilted supports. The systems are connected to different types of inverter, through which the power monitoring is performed. The assessment shows indicators, such as final yield and performance ratio, for both tracked and fixed-tilt systems. The PV systems are evaluated in relation to irradiance data registered by two identical c-Si reference devices positioned on the tracker and on the fixed supports. Results show that an average difference of ±14 W exists between the module's label and the actual peak power. This difference is in line with the power tolerance declared by manufacturers. The maximum-power-based PV performance validation method could initially highlight cases in which a faulty module hides in the system, having the potential for application in fault detection and reliability analysis, followed by more specific evaluations. © 2012 IEEE.

To lighten up your week and give you even more energizing thoughts, we publish interviews from our partner The Beam twice a week. The Beam takes a modern perspective at the energy transition, interviewing inspirational people from around the world that shape our sustainable energy future. This week, Anne-Sophie Garrigou, journalist at The Beam, interviewed Wolfram Sparber, Head of the Institute for Renewable Energy at The European Academy of Bozen/Bolzano (EURAC), about the Institute and his thoughts on the future of renewable energy. What are the main goals of the Institute for Renewable Energy of EURAC Research? EURAC Research is a private research center located in Bolzano, South Tyrol. The aim of the Institute for Renewable Energy is to carry out applied research on advanced energy systems to support the application of renewable energy and energy efficiency technologies and assist decision-makers through scientific consultancy. The field of activities are energy efficiency in buildings, working as well in the niche application of historic buildings, sustainable heating and cooling systems, PV systems and energy systems on urban and regional scale. The Institute works closely with industry partners and other research centers in order to develop new energy systems, applications and products. What technological breakthroughs will make a big change in the field of production and storage of renewable energy? In our opinion, there will not be one unique technology, which will change the energy scheme. The energy world is a complex system, where further evolutions in all main sectors are needed. We have to consider electricity, heating & cooling as well as transportation. Evolutions in the field of energy production, distribution, storage and efficient consumption is necessary. In the field of electricity production, it is necessary to apply existing technologies on a large scale in order to widely substitute fossil fuels in the coming decades. Technology evolution will contribute to continue the cost reduction curves of recent years. Regarding storage, in our opinion, distributed storage possibilities (e.g. electric vehicles) and application of demand side management will keep the necessity of large-scale centralized storage infrastructure limited. A large potential exists and has until now been tapped in a limited way in the field of energy efficiency measures and application of renewable technologies in the heating sector. This sector is the most important in terms of ‘final energy consumption’ in Europe because it accounts for over 40%. The big question here is how to bring the technologies and methods for building refurbishment from single buildings to massive and large scale applications in a cost effective way. In this field, we are working on several projects in the development of prefabricated multifunctional façades. The target is to produce individual façade components in an industrial way, including cost control and quality assurance. The façade should allow high energy efficiency, high comfort, attractive aesthetics, eventually the integration of solar active elements, heat distribution systems or air ventilation systems. Furthermore the disturbance time during construction on site for the tenants living in the building should be reduced to single days. This is possible as large scale prefabricated elements are fixed on the existing walls of the building. Through district heating networks, thermal storage, cogeneration and heat pumps it is further possible to interlink and optimize the thermal and electrical grid management. In this field we are working, for example, on very low temperature district heating systems with multiple heat sources, in combination with heat pumps allowing to reduce heat losses of the grid and to better integrate waste heat from the industry or service sector (flexynets.eu). According to your research, which branch of renewable energy offers the best hope for our energy future? Again, there is not a single branch; the potential of a renewable energy source or system is strictly related to the characteristics and the circumstances of a given country. Electricity from solar PV and wind has shown in recent years in many countries how substantial their contribution can be. Geothermal energy and solar thermal power plants are in many geographical areas used only in a limited way. Biomass and biogas plants can be integrated well in regional energy concepts. With regard to heating and cooling, advanced district heating systems offer the possibility to include several renewable energy sources and waste heat sources, and to deliver this energy to the point of consumption. Solar thermal and geothermal systems have a large potential, which is still widely unexploited in Europe. On single building level, heat pumps will probably play a relevant role in the next years. -> Subscribe to The Beam. Tri-annual subscriptions for the Beam from 10€ to 20€ per edition. Help us #buildthebeam Buy a cool T-shirt or mug in the CleanTechnica store!   Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech daily newsletter or weekly newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.

D'Antoni M.,Institute for Renewable Energy | Saro O.,University of Udine
Renewable and Sustainable Energy Reviews | Year: 2012

The present work reviews the literature produced so far on high-capacitance solar thermal collectors, with the aim of highlighting the wide range of possible variants and applications and sharing the information here gathered for future developments. These solar systems are here denoted with the term of Massive Solar-Thermal Collector (MSTC). The review is focused on liquid rather air technologies, because of their direct applicability to systems that supply only domestic hot water (DHW) as well as combined DHW and space heating (SH) systems. The attention on this topic is justified by the rising number of publications and energy concepts that deal with the utilization of opaque structures as low cost solar absorbers and by the similar MSTC's efficiency in low temperature range to conventional solar systems. © 2012 Elsevier Ltd. All right reserved.

D'Antoni M.,Institute for Renewable Energy | Saro O.,University of Udine
Solar Energy | Year: 2013

The aim of this work is to investigate the energy potential of using exposed concrete structures as solar energy absorbers (here denoted with the general term of Massive Solar-Thermal Collectors, MSTCs) during the heating period and in particular the design of a Concrete Solar Collector (CSC) is then presented. The CSC is a particular kind of MSTC, conceived as an exposed free standing structure that embeds a coiled pipe heat exchanger in a massive-concrete matrix. A numerical design model has been developed and parametric simulations have been conducted in order to get a figure of the energy potential of the CSC under different European climate conditions. The CSC has reached an energy yield of 460.77kWh/m2/y and an average heat flux of 93.07W/m2 for the reference climate of Stuttgart (Germany) during the winter season (inlet fluid temperature of -5°C and mass-flow rate of 45kg/h/m2). The Elementary Effect Method has been adopted as Sensitivity Analysis procedure with the aim of understanding the dependency of design parameters on the energy output. Finally, an economic analysis has been carried out by comparing investment costs and energy outputs. © 2013 Elsevier Ltd.

Dunjic S.,Joule Assets Europe Rue duTrone 61 | Pezzutto S.,Institute for Renewable Energy | Zubaryeva A.,Institute for Renewable Energy
Renewable and Sustainable Energy Reviews | Year: 2016

The goal of this paper is to analyze recent developments in the renewable energy sector in the Western Balkans – Albania, Bosnia and Herzegovina, Croatia, Kosovo, Macedonia, Montenegro, Serbia, and Slovenia. In order to achieve this goal, existing knowledge gaps regarding the use of renewable energy as a share of the region׳s final energy consumption had to be filled in. This was done by creating a reliable model for the calculation of these shares for the years 2010 and 2011. The results were then put together with the official data for the years 2009, 2012, and 2013, and a linear trend forecast was included based on the combined data. In this way it was possible to make an estimation of the time frame in which the countries with positive linear trend results would reach their renewable energy use targets. The results of the analysis show inconsistent development of renewable energy sources for countries outside of the EU. Combined with political challenges, such as the natural gas crisis of 2009, this creates increased volatility in the proportion of renewable energy in final energy consumption. Additionally, regulatory and market issues ranging from a lack of appropriate legislation and complicated administrative procedures, to poor coordination between various institutions act as barriers to increased investment in renewable energy. © 2016 Elsevier Ltd

Sartori I.,Sintef | Napolitano A.,Institute for Renewable Energy | Voss K.,University of Wuppertal
Energy and Buildings | Year: 2012

The term Net ZEB, Net Zero Energy Building, indicates a building connected to the energy grids. It is recognized that the sole satisfaction of an annual balance is not sufficient to fully characterize Net ZEBs and the interaction between buildings and energy grids need to be addressed. It is also recognized that different definitions are possible, in accordance with a country's political targets and specific conditions. This paper presents a consistent framework for setting Net ZEB definitions. Evaluation of the criteria in the definition framework and selection of the related options becomes a methodology to set Net ZEB definitions in a systematic way. The balance concept is central in the definition framework and two major types of balance are identified, namely the import/export balance and the load/generation balance. As compromise between the two a simplified monthly net balance is also described. Concerning the temporal energy match, two major characteristics are described to reflect a Net ZEB's ability to match its own load by on-site generation and to work beneficially with respect to the needs of the local grids. Possible indicators are presented and the concept of grid interaction flexibility is introduced as a desirable target in the building energy design. © 2011 Elsevier B.V. All rights reserved.

D'Antoni M.,Institute for Renewable Energy | Romeli D.,Institute for Renewable Energy | Fedrizzi R.,Institute for Renewable Energy
Applied Energy | Year: 2016

This paper presents the development of a numerical model of a hybrid cooler for transient simulation purposes as a component of a thermal energy system. The model uses a modular definition of the control volume, and is suitable for modelling any staggered coil geometry. The set of parameters required for modelling the hybrid cooler is typical of the so-called design models. A rigorous analysis of sensible and latent heat fluxes due to spray water evaporation is included. Further, the model can be exploited for the development of user-defined control strategies of fans and water spray systems. The model is validated using monitored data from a pilot system installation in which a commercial hybrid cooler is operated under typical summer south European working conditions. © 2016 Elsevier Ltd

Belleri A.,Institute for Renewable Energy | Belleri A.,University of Bergamo | Lollini R.,Institute for Renewable Energy | Dutton S.M.,Lawrence Berkeley National Laboratory
Building and Environment | Year: 2014

We present a study of natural ventilation design during the early (conceptual) stage of a building's design, based on a field study in a naturally ventilated office in California where we collected data on occupants' window use, local weather conditions, indoor environmental conditions, and air change rates based on tracer-gas decay. We performed uncertainty and sensitivity analyses to determine which design parameters have most impact on the uncertainty associated with ventilation performance predictions. Using the results of the field study along with wind-tunnel measurements and other detailed analysis, we incrementally improved our early-design-stage model. The improved model's natural ventilation performance predictions were significantly more accurate than those of the first draft early-stage-design model that employed model assumptions typical during initial design. This process highlighted significant limitations in the EnergyPlus software's models of occupant-driven window control. We conclude with recommendations on key design parameters including window control, wind pressure coefficients and weather data resolution to help improve early-design-stage predictions of natural ventilation performance using EnergyPlus. © 2014 Elsevier Ltd.

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