In recent years, the building sector has received increasing attention with attempts to limit its energy consumptions and GHG emissions. In fact, buildings account for more than 30% of the overall ...energy demand worldwide, with projections for increases in this quota due to climate changes, urbanization, and higher living comfort standards. This study investigates the effects of climate changes on the heating and cooling energy demand of buildings in the most populated urban region in Canada, i.e. the city of Toronto in Ontario. Statistical and dynamical downscaling methods are utilized to generate several future weather files, starting from different baseline climates including the old Canadian Weather Year for Energy Calculation CWEC (representing the 1959–1989 period) and the new CWEC 2016 (representing the 1998–2014 period). In dynamical downscaling, a regional climate model is used to obtain a finer resolution than traditional general circulation models. The generated future weather data sets are then used for simulating the energy demand of 16 building prototypes. The simulation results show an average decrease of 18%–33% for the heating energy use intensity, and an average increase of 15%–126% for the cooling energy use intensity by 2070, depending on the baseline climatic file of use and building typology. The forecasted GHG emissions of each building prototype are then discussed. The results demonstrate the need to perform building modelling with sensitivity analysis of future climate scenarios in order to design more resilient buildings.
•Future weather files using both statistical and dynamical downscaling are generated.•Higher temperatures would lead to a reduction of Heating Degree Days of 30% in Toronto by 2070.•Energy use intensity and GHG emission according to future weather files are presented.•Results predict a decrease of the heating EUI by 18–33% and an increase of cooling EUI by 15%–126% in future.•Recommendations about using future weather files in building performance simulations are provided.
Passive vibration absorbers are really effective only at the tuned frequency. This limit is overcome by adaptive absorbers which offer the possibility to adjust their behaviour according to needs. ...The paper focuses on a smart actuator for vibration control made up by a dielectric electro-active polymer (DEAP). The DEAP is obtained constraining a silicone corrugated sheet between two silver layers and it is manufactured by Danfoss Polypower A/S. The actuator is fabricated by rolling the DEAP sheet in a cylindrical and core-free shape. The paper describes the static and dynamic characterizations of the actuator. A theoretical model is developed by considering the actuator as a multi-elements model. Moreover, a modal test of the actuator is performed driving it with an electro-dynamic shaker in a frequency range up to 1 kHz. A good agreement between theoretical and experimental data is obtained at lower frequencies. Stiffness and damping laws of the actuator are determined by fitting theoretical expectations and test results. The actuator is proved useful for controlling vibrations at low frequencies because it shows internal resonances at frequencies above 75 Hz. Finally, first results about the use of the DEAP actuator for vibration control of harmonic excitations in a band-limited frequency range below 10 Hz are reported.
Renewable energy communities (REC) are key drivers in promoting energy transition to renewable energy sources (RES). To maximise local potential for RECs, matching demand and local production ...requires the integration of different load profiles. Residential users prevail in urban areas while planning mixed-use neighbourhoods would contribute to having complementary loads towards urban RECs. Mixed areas can optimise the use of renewable production at different hours and limit demand pressures on the network. However, detailed spatial analyses are required to cluster building functions for long-term benefits. This work investigates which mix of building functions in urban blocks can maximise energy self-consumption and self-sufficiency. Five blocks combining residential with productive and tertiary activities are chosen, from a completely residential to a heterogeneous mix. The single loads use representative buildings for the Italian context. The integration of building functions flattens the energy peak loads in the district while increasing the use of PV production. The study identifies the residential and non-residential ratios to maximise energy selfconsumption and self-sufficiency. Domestic users would mainly exploit the production from nearby non-domestic buildings, but adequate exchange mechanisms and upgrade of infrastructure still need to be implemented.
This paper discusses the main challenges of using fiber reinforced polymers (FRPs) in architectural applications. Architects are showing increased interest in the use of FRPs in modern buildings ...thanks to FRPs’ ability to allow cost effective realization of unique shapes and flexible aesthetics, while accommodating architectural designs and needs. The long-term durability, weathering resistance, and the exceptional mechanical properties have recently suggested the adoption of FRPs for building façade systems in an increasing number of buildings worldwide. However, some challenges for a wider adoption of FRPs in buildings are represented by the environmental and thermal aspects of their production, as well as their resistance to the expected “fire loads”. This last aspect often raises many concerns, which often require expensive fire tests. In this paper, the results of cone calorimeter tests are compared with software simulations to evaluate the possibility of designing FRPs on the computer as opposed to current design practice that involves iterative use of fire testing. The comparison shows that pyrolysis simulations related to FRPs are still not an effective way to design fire safe FRPs for architectural applications.
Display omitted
Vacuum insulation panels (VIPs) encompass a higher thermal resistance per unit of thickness compared to any other kind of insulation. However, their aging has often shown some ...critical concerns. To support the broader use of VIPs in the building sector, their physical properties, and in particular their thermal conductivity, over long-periods should remain consistent. This study investigates the effect of extreme temperature and relative humidity cycling on the service life and thermal conductivity of VIPs. The scope is to validate existing theoretical aging models for VIPs. First, the experimental results of the thermal conductivity for five VIPs in pristine and in laboratory-accelerated conditions are reported. The thermal conductivity in pristine conditions of the selected materials ranged between 0.0028 and 0.007W/mK. The results of the thermal conductivity values after several aging conditions are reported in the temperature range from −20°C to +40°C. Then, an analytical aging method is employed to validate the collected data. Results show that aging has a more significant impact on the performance of VIPs with a core of fiberglass-core than on VIPs with a core of fumed silica. However, for all the investigated VIPs the service life corresponding to the thermal conductivity of 0.008W/mK was higher than 25 years, confirming the reliability of these insulating systems.
Natural materials are becoming a valid alternative to traditional synthetic ones for sound absorption treatments. In particular, in recent years, natural fibers have been considered valid raw ...materials for producing sound absorbing panels at a reduced cost. Moreover, these fibers often have good thermal insulation properties, have no harmful effects on health, and are available in large quantities often as a waste product of other production cycles. Following a literature review of previous studies about the acoustic properties of some natural materials, this paper reports the acoustical characterization of the following natural fibers: kenaf, wood, hemp, coconut, cork, cane, cardboard, and sheep wool. The absorption coefficient and the flow resistance for samples of different thickness have been measured. By using existing theoretical models, this study also compares the measured behavior with the theoretically predicted behavior. This comparison shows the limits of theoretical models originally defined for porous materials with homogeneous fibers, when they are applied to natural materials. Finally, some suggestions for use of these natural fibers for sound absorption applications in buildings are reported.
•Natural fibers are a valid option for sound absorption treatments.•Kenaf, wood, hemp, coconut, cork, cane, cardboard, and sheep wool are characterized.•The airflow resistivity and the sound absorption coefficient are measured.•Given their inhomogeneity, natural fibers often do not agree to the Delany–Bazley model.•Existing theoretical models fail in considering the inhomogeneity of natural fibers.
Latent heat thermal energy storage (LHTES) using phase change materials (PCM) is one of the most promising ways for thermal energy storage (TES), especially in lightweight buildings. However, ...accurate control of the phase transition of PCM is not easy to predict. For example, neglecting the hysteresis or the effect of the speed of phase change processes reduces the accuracy of simulations of TES. In this paper, the authors propose a new software module for EnergyPlus™ that aims to simulate the hysteresis of PCMs during the phase change. The new module is tested by comparing simulation results with experimental tests done in a climatic chamber. A strong consistency between experimental and simulation results was obtained, while a discrepancy error of less than 1% was obtained. Moreover, in real conditions, as a result of quick temperature changes, only a partial phase transformation of the material is often observed. The new model also allows the consideration of the case with partial phase changes of the PCM. Finally, the simulation algorithm presented in this article aims to represent a better way to model LHTES with PCM.
The speech intelligibility properties of classrooms greatly influence the learning process of students. Proper acoustics can promote the inclusion of foreign students and children with learning or ...hearing impairments. While awareness of the topic is increasing, there is still no parameter that can describe all aspects of speech transmission inside a room. This complicates the design of classrooms and requires designers to have extensive knowledge of theory and experience. In the scientific and technical literature, there is a lack of predictive tools, easy to use by designers, which can guide the choices in the early design stages in order to move towards technical solutions able to ensure adequate levels of speech intelligibility. For this reason, in this paper, the most relevant speech intelligibility parameters found in the literature were collected and discussed. Among these, the Clarity index and Speech Transmission Index were singled out as the most effective ones, whose prediction can be made with relatively simple methods. They were then analyzed through their prediction formulas, and a tool was proposed to allow an easy estimation of the minimum total equivalent sound absorption area needed in a classroom. This tool greatly simplifies the early acoustics design stage, allowing the intelligibility of speech within a classroom to be increased without requiring much theoretical effort on the part of the designers.
The building sector is accountable for about one-third of the global energy consumption and contributes to 19% of greenhouse gas (GHG) emissions relating to energy processes. Given the changing ...climate and its impact on building heating and cooling demands, energy models based on historical weather data cannot accurately simulate the performance of a building in the future. Accordingly, this paper generated several future weather data sets and applied them to the energy simulation of 16 ASHRAE reference building models for Toronto, Canada. Both statistical and dynamical downscaling techniques were used for generating these future weather files. The results indicate an average decrease of 17.8-27.2% in heating loads and an average increase of 13.5-55.4% in cooling loads, depending on the building type, leading to an overall decrease in energy use intensity (EUI) for the majority of the 16 reference building models. It is concluded that the application of future weather files for building performance simulation leads to a more realistic quantification of building energy demand in the future. Furthermore, depending on the availability and accuracy of regional climate models (RCM), the weather files generated using dynamical downscaling provide a more reliable forecast of the local boundary conditions for building performance simulation.
PDF
