1,720,961 research outputs found
On the use of FEM and FDTD numerical methods to predict acoustic behavior of small rooms
No full textEconomic-environmental performance indexes for solar-powered absorption cooling system in Mediterranean area
No full textThe most recent European (Directive 2006/32/CE of April 5/2006 relating to the efficiency of the final
uses of the energy and the energetic services) and national (Decree 311/06) normatives impose the use of
energetic systems more efficient that minimize the use of fossil fuels in comparison to the use of
renewable energy. In this research a comparison was developed between the traditional electric
equipments (which use vapour compression) and the absorption equipments (powered by solar thermal
energy). This comparison was implemented considering the energetic, economic and environmental
aspects.
This research explores the technical - economic potentialities of solar HVAC systems, with particular
reference to those based on the absorption cycles, verifying the possible applications in regions of the
Mediterranean area (in particular Madrid, Palermo and Athens). In particular we define an economic
index and an environmental-energetic inde
Microclimatic performance of a restored hypogeum: the case of “Locanda di San Martino” thermal centre (SPA)
No full textThe site of the “Sassi di Matera” classified by the United Nations Educational, Scientific and Cultural Organization (UNESCO) as World Heritage in 1993, is an exceptional example of traditional bioclimatic Mediterranean architecture.
This site is located in Basilicata in southern part of Italy and is characterized as having a Mediterranean climate, with hot dry summers and temperate and humid winters.
The average seasonal temperature is 4 _C in winter and 32 _C in summer, which often has high values close to 40 _C. Moreover winter is mild with rare frosts. Rains are mostly concentrated in autumn and winter.
Within this immense artistic heritage, the study regars hypogea habitations and stone buildings (half-hypogeum and half-built), throught monitoring a surface hypogeum and a deep hypogeum. The research focus upon the evaluation of the energy and microclimatic performance of recovered hypogeous structures today used as a thermal centre (SPA).
The analysis performed a dynamic parametric simulation using the software EnergyPlus to quantify the energetic balance of the hypogeous structures during one calendar year. The energetic valuation of the surface hypogea shows that these environments, once restored and in a condition of normal use, give indoor comfort within the limits of comfort thermo-hygrometrics.
The methodology used in the research is that of empirical research, i.e. a direct study “in situ”, where the designer is an experimenter and a researcher at the same time. This methodological approach was used on particularly representative case studies: “Locanda di San Martino” thermal centre (SPA).
The huge thermal mass of the walls ensures that the microclimate indoor conditions are regular throughout the seasons, without differences in the daily thermal oscillation. Deep hypogea with an air change system cannot reach thermal-hygrometric comfort values.
The most important thing to do is to regulate indoor microclimate, before eliminating the humidity from the walls. The same environments used under normal conditions reach indoor comfort.
During the summer season the indoor temperature is in the comfort. Then these buildings often need to be heated during the summer season to shorten the huge indoor/outdoor thermal gradient.
Deep hypogeous architectures without an air change system cannot reach thermal-hygrometric comfort values. This system is useful in increasing the indoor temperature and reducing the indoor–outdoor thermal gradient. A dynamic analysis permitted us to quantify the energy balance of the hypogeous structures during a period of one calendar year. In this way, we can state that these structures have a null thermal balance during mid-season, while in summer the floor loses heat and cools the room with the opposite occurring in winter.
It can conclude that these buildings were designed as bioclimatic. In fact they can be used, after restoration, with limited use of technology systems
Energy and Microclimatic Performance of Restored Hypogeus Buildings in South Italy: the "Sassi" District of Matera
No full textThe site of the ‘‘Sassi of Matera’’ classified by the United Nations Educational, Scientific and Cultural
Organization (UNESCO) as World Heritage in 1993, is an exceptional example of traditional bioclimatic
Mediterranean architecture. Within this immense artistic heritage, we find hypogea habitations, stone
buildings, and mixed habitation – half-hypogeum and half-built. In this study, we analyze the energy and
microclimatic performance of hypogeous structures in three states: not-restored, immediately after
restoration, and a few years after restoration (in normal use). We monitored a surface hypogeum and
a deep hypogeum. We performed a dynamic parametric simulation using the software EnergyPlus to
quantify the energetic balance of the hypogeous structures during one calendar year. The energetic
valuation of the surface hypogea shows that these environments, once restored and in a condition of
normal use, give indoor comfort within the limits of comfort thermo-hygrometrics established by the
comfort indices of predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD). The huge
thermal mass of the walls ensures that the microclimate indoor conditions are regular throughout the
seasons, without differences in the daily thermal oscillation. Deep hypogea without an air change system
cannot reach thermal-hygrometric comfort values. We determined that these structures have a null
thermal balance during mid-season, while in the summer the floor loses heat, thereby cooling the
environment. The opposite occurs in winter. We can conclude that these buildings were designed as
bioclimatic. In fact they can be used, after restoration, with limited use of technology systems
Passivhaus”: indoor comfort and energy dynamic analysis
No full textThe research aims to verify the energy performance as well as the indoor comfort of an energy class A+ building, built so that the sum of the heat passive contributions of solar radiation, transmitted through the windows, and the heat generated inside the building, are adeguate to compensate for the envelope loss during the cold season.
The building, located in Emilia Romagna (Italy), was built using a wooden structure, an envelope realized using a pinewood sandwich panels (transmittance U = 0.250 W/m2K) and, inside, a wool flax insulation layer and thermal window frame with low-emissivity glass (U = 0524 W/m2K). The building design and construction process has followed the guidelines set by “CasaClima”. The building has been modeled in the code of dynamic calculation "Energy Plus" by the Design Builder application and divided it into homogenous thermal zones, characterized by winter indoor temperature set at 20 ° (+ / - 1 °) and summer indoor temperature set at 26 ° (+ / - 1 °). It has modeled: the envelope, as described above, the "free” heat contributions, the air conditioning system, the Mechanical Ventilation system as well as home automation solutions. The air conditioning system is an heat pump, able to guarantee an optimization of energy consumption (in fact, it uses the "free" heat offered by the external environment for conditioning indoor environment).
As regards the air recirculation system, it has been used a mechanical ventilation system with internal heat cross-flow exchanger, with an efficiency equal to 50%. The domotic solutions, instead, regard a system for the control of windows external screening using reeds, adjustable as a function of incident solar radiation and a lighting management system adjusted automatically using a dimmer.
A so realized building meets the requirement imposed from Italian standard UNI/TS 11300 1, UNI/TS 11300 2 and UNI/TS 11300 3.
The analysis was performed according to two different configurations: in “spontaneous-state analysis” (that provides the only energy performance of the structure) and considering the “building-equipments” as a system (which provides the overall performance of the "building system"). The first analysis shows as the absence of thermal mass and the envelope super-heating prevent to incoming heat to exit, overheating the indoor environment.
The analysis of the overall performance of the "building system" highlights, instead, as the thermal load is much greater during the summer than in winter; this means that, using a low inertia envelopes, the energy saved in the winter can be used to satisfy the thermal performance in the summer.
This is further demonstrated by comparing the performance of indoor temperatures and the relative energy consumption of a similar building with greater thermal inertia.
Further analysis involved a critical comparison between the “semisteady-state analysis” (“CasaClima” methodology) and the analysis in dynamic conditions (using "Energy Plus" software)
Modelling Analysis for Energy production Using Wood Biomass
No full textThe energy production from biomass is the technology that receives the greatest wariness from outsiders. Combustion and emission of air pollutants, the identification of an any biomass plant with a waste energy
power plant, often interfere with the diffusion of these technologies of energetic conversion at local level. This paper gives rise to describe the characteristics of the operation of a plant for the exploitation of the
wood biomass from a short productive chain. The aim is to propose a possible and advantageous solution from a technical and economic point of view but, above all, ecological, with the purpose to create a useful
tool to relate with the stakeholders that operate in the agricultural and industrial sector. The use of the ORC (Organic Rankine Cycle) energy technology is a solution by now tested and particularly suited for
working joint to small size thermal plant operating at low temperature. In this paper, the obtainable energy performances by means of such energy plant joint to boilers fed with wood biomass will be analyzed showing the results of an energy and exergetic modelling of the ORC units. The proposed solution consists in the integration of the firewood boilers with a circuit of diathermic oil able to feed the ORC plant. In this way, we produce power and heat, to be used also for district heating applications, to reach a more complete energy exploitation of the biomass. The simulation model of this energy system has allowed to get with good approximation the obtainable performances, varying some free parameters of design and control, shaping itself as an essential tool in the evaluation of the actual energy saving and of the concrete technical-economic feasibilit
Thermal properties of the vernacular buildings envelopes: the case of the “Sassi di Matera” and “Trulli di Alberobello
No full textThe stone and the clay are the basic elements of the existing architectural heritage in the Mediterranean
area, both historical and monumental. The study cases taken into account are the "Sassi of Matera" and
the "Trulli of Alberobello." The thermohygrometric performances of the "Tufo of Matera" (commonly
denoted as calcarenite sandstone) and the "Stone of Fasano" (commonly denoted as calcareous stone),
which are the base materials of the buildings "Sassi" and "Trulli", were quantified through measurements
in situ, realized with nondestructive methodology and analyses in laboratory. The behavior of these
constructions has finally been better described with dynamic simulations developed by the software
EnergyPlus. This study demonstrated that the thermal mass of these structures mainly affect the indoor
microclimate, stabilizing the inside temperatures and thus annulling the great thermal daily oscillations
of the external temperature. The results of the measurements and numerical simulations confirmed that
the seasonal thermal storage of these structures allows comfortable temperatures during the summer
season, with values below 26°C, and stabilizes the indoor temperatures during the winter season, through
the release of the heat stored during warm season
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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