117,286 research outputs found
Evaluation of ISO 52010-1: 2017 and proposal for an alternative calculation procedure
No full textA proper evaluation of the building energy consumption implies an accurate assessment of the solar gains and consequently an exact estimation of the direct and diffuse solar radiation on tilted and oriented surfaces. The new standard EN ISO 52016-1: 2017 introduces a new hourly methodology for the calculation of energy performance of buildings and is complemented by EN ISO 52010-1:2017, which specifies the procedure for the conversion of climate data for energy calculations. These standards represent a good compromise between the old EN ISO 13790:2008 and Trnsys, since they allow for a more accurate evaluation of energy consumption than the former, while being less onerous than the latter. In the present work, EN ISO 52010-1:2017 is analysed for the first time and an alternative calculation procedure is proposed. These two algorithms are then compared with two other irradiance splitting methods implemented in Meteonorm and Trnsys code. In order to test performance and limits of the different calculation algorithms, we make a comparison among such methods on five European cities characterized by different climatic characteristics. Results show that the model implemented in EN ISO 52010-1:2017 overestimates the diffuse solar irradiance on horizontal plane for all the considered locations, while the proposed procedure and those implemented in the Trnsys and Meteonorm softwares show similar results. Using Trnsys algorithm as a baseline, the proposed calculation algorithm gives the best approximation among the considered models for what concerns the direct, diffuse and global irradiance on vertical surfaces exposed to south, east and west
Impact of climate change on the energy and comfort performance of nzeb: A case study in Italy
No full textClimate change is posing a variety of challenges in the built realm. Among them is the change in future energy consumption and the potential decay of current energy efficient paradigms. Indeed, today’s near-zero Energy buildings (nZEBs) may lose their virtuosity in the near future. The objective of this study is to propose a methodology to evaluate the change in yearly performance between the present situation and future scenarios. Hourly dynamic simulations are performed on a residential nZEB located in Rome, built in compliance with the Italian legislation. We compare the current energy consumption with that expected in 2050, according to the two future projections described in the Fifth Assessment Report (AR5) by the Intergovernmental Panel on Climate Change (IPCC). Implications for thermal comfort are further investigated by assuming no heating and cooling system, and by tracking the free-floating operative temperature. Compared to the current weather conditions, the results reveal an average temperature increase of 3.4◦ C and 3.9◦ C under RCP4.5 and RCP8.5 scenarios, estimated through ERA-Interim/UrbClim. This comes at the expense of a 47.8% and 50.3% increase in terms of cooling energy needs, and a 129.5% and 185.8% decrease in terms of heating needs. The annual power consumption experiences an 18% increase under both scenarios due to (i) protracted activation of the air conditioning system and (ii) enhanced peak power requirements. A 6.2% and 5.1% decrease in the hours of adaptive comfort is determined under the RCP4.5 and RCP8.5′ s 2050 scenarios out of the concerted action of temperature and solar gains. The results for a newly proposed combined index for long-term comfort assessments reveal a milder future penalty, owing to less pronounced excursions and milder daily temperature swings
Thermal performance of a massive wall in the Mediterranean climate: Experimental and analytical research
No full textIn the Mediterranean climate, indoor overheating and, thus, excessive use of cooling systems represents one of the main problems both for the occupants' health and energy consumption. In order to limit this problem, an appropriate design or energy retrofitting of the building envelope is of utmost importance. The predominance of massive buildings in the Italian territory and the need to comply with Italian regulations often leads technicians to not optimal energy saving solutions. To this purpose, this experimental research was conducted on a mockup building, located in Fabriano and characterized by high thermal mass walls (W0) and two different external insulating systems: Cork based lightweight plaster (W1) and Extruded polystyrene foam panel (XPS) (W2). Furthermore, a virtual model in TRNSYS, a transient simulation software, was used to compare analytical and simulated values. Results show that W2 undergoes a higher level of thermal stress than W1, due to higher peaks in the external surface temperature and larger fluctuations in daily temperature. Therefore, a high value of thermal resistance of the external insulation and low value of external areal heat capacity on a massive building causes external surface overheating problems, thus, not representing the optimal construction solution
Data-driven automation of HVAC systems: An experimental study in a university study room
No full textThis study proposes a framework for controlling HVAC systems for university study rooms that includes a data-driven model capable of identifying the probability of user interaction with air conditioning and ventilation systems, depending on the thermal sensation vote (TSV), perceived air quality (PAQ) and microclimate parameters (air and operative temperature, air velocity, relative humidity and CO2). The experimental setup allowed the participants to carry out their usual study/work activities without the need to be supervised. This allowed the occupants not to be psychologically conditioned and made their experience and interaction with the environment/systems as realistic as possible. The analysis of the experimental data showed that the operative temperature mainly influences the thermal sensation of the occupant inside the room, while the perceived air quality depends not only on the CO2 concentration but also on thermal perception and air velocity. Furthermore, three predictive models (heating, cooling and IAQ) were obtained from the experimental data, indicating the probability of user interaction with the system (R2 between 0.85 and 0.94). The heating phase model was also verified by automatizing the heating system through the developed framework and comparing the user's sensations before and after control (users unaware of the changes). The use of the models increased users' thermal comfort from 39 % to 82 %, confirming the effectiveness of the syste
Improving Indoor Air Quality with Green Walls: An Experimental Study
No full textPoor indoor air quality (IAQ), particularly elevated CO2 concentrations, is known to impair cognitive function and comfort. In sealed or energy-efficient buildings, natural air exchange is limited, increasing the need for passive pollutant removal strategies. This study evaluates the CO2 removal capacity of a living wall system installed in a full-scale climatic chamber (38 m3). Controlled CO2 decay tests were performed under two conditions: with LED illumination (photosynthesis active) and without lighting. The temporal evolution of CO2 concentration was modeled using a first-order exponential decay function, and equivalent air change rates (ACHe) were calculated. Under illumination, the half-life of CO2 decreased from 90 to 63 minutes (- 30%), with an additional removal of approximately 6 g of CO2 over 6 hours. The ACHe increased from 0.46 h-1 (LED OFF) to 0.66 h-1 (LED ON), representing a 43% improvement in effective air renewal attributable to photosynthesis. The findings confirm the synergistic role of lighting and vegetation in enhancing passive indoor air purification. Properly illuminated living walls (LWs) can achieve substantial CO2 removal rates, offering a sustainable strategy for improving IAQ in energy-efficient buildings
Educational Buildings: Analysis of IAQ as a Function of Occupant Behavior and Mechanical Ventilation Systems
No full textFollowing the health emergency caused by SARS-CoV2, the MarcheRegion (Italy) implemented a series of interventions to finance mechanical ventilation systems in schools. These interventions enabled the implementation of ameasurement campaign to evaluate the functioning of mechanical ventilation insideeducational buildings. Specifically, the following study investigates the dynamicsregarding IAQ according to occupant behavior and the presence or absence of ventilation system on three different classrooms by analyzing the trend of measured CO2concentration. From the results obtained, it is evident that the classroom without aventilation system reaches much higher CO2 values than the classrooms with theventilation system, with a difference from the maximum values of 45.3%. In addition, the combination of natural ventilation and mechanical ventilation is crucial toobtain acceptable CO2 levels. These aspects are directly related to the behavior ofoccupants (opening/closing windows, using the ventilation system), who must beinformed about the various ventilation strategies and directed toward their conscioususe
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
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