While cool materials are widely acknowledged for lowering surface and air temperatures, mitigating Urban Heat Island, reducing emissions imputable to active cooling systems in buildings, concerns ...arise about their impact on pedestrians' thermal and visual perception. These materials are typically applied on roofs, urban paving and building envelope: when the application is on non-usable spaces for pedestrians, it represents a win-win solution, since it decreases thermal stresses with no penalties for pedestrians. Instead, if the cool surface is installed over a passage area, glare and thermal radiative stress could affect pedestrians' comfort perception. In this work, a naturally cool, light colored stone is considered in the form of aggregates with varying grain size for cool roofing and paving application. Therefore, given its intrinsic passive cooling effect, this paper wants to experimentally investigate if such sustainable and cost effective material can create sensible thermal/visual discomfort perceived by pedestrians. To this aim, pedestrians' perception is investigated by means of in-situ survey and continuous monitoring in summer variable weather conditions, by taking into account several paving systems, i.e. grassland, asphalt, natural stones, and the investigated cool stone aggregates. The study demonstrated how in hot and sunny weather conditions, pedestrians prefer grassland, while asphalt is the least favorite material in any case. Cool gravel based surface does not produce thermal discomfort but it produces some visual discomfort due to glare issue, only in sunny weather conditions. In fact, variable weather conditions significantly affect pedestrians' sensitivity and their preference, also in the same summer season.
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•Cool, green natural and low cost materials are studied for roofing and urban paving.•Pedestrians' thermal and visual comfort comparison has been carried out in summer.•Albedo, weather conditions, personal features of the interviewees are surveyed.•Cool gravels better perform thermally than asphalt, but grass is always preferred.•Cool gravels do not produce visual discomfort in cloudy days even in summer.
Life Cycle Assessment is widely utilized to investigate the influences on global greenhouse gas emissions of various humankind activities and products ...
A systematic analysis of green-house gases emission (carbon footprint) and primary energy consumption (energy footprint) of prefabricated industrial buildings during their entire life cycle is ...presented. The life cycle assessment (LCA) study was performed in a cradle-to grave approach: site-specific data from an Italian company, directly involved in all the phases from raw material manufacturing to in-situ assembly, were used to analyze the impacts as a function of different design choices. Four buildings were analyzed and results were used to setup a parameterized model that was used to study the impacts of industrial prefabricated buildings over the input parameter space. The model vs. data agreement is within 4% for both carbon and energy footprint. The functional unit is 1 m3 of prefabricated building, considering a 50-year lifetime. The results of the four buildings decrease from 144.6 kgCO2eq/m3 and 649.5 kWh/m3 down to 123.5 kgCO2eq/m3 and 556.8 kWh/m3 as the building floor area increases from 1048 m2 to 21,910 m2. The use phase accounts for the major impact (approximate 76%). It is found that the carbon footprint is proportional to the energy footprint, the proportional factor being 0.222 kgCO2eq/kWh within 0.5% accuracy. Finally, a systematic study of the sensitivity of input parameters (insulation, lifetime, foundation type) is presented.
The growing economic efforts and investment for the production of green hydrogen make the definition of new competitive and environmentally friendly storage methods. This article deals with the ...proposal of gas hydrate production with binary or ternary H2-based gaseous mixtures for hydrogen storage. In the text, the physical and chemical elements necessary to confirm the technical feasibility of the process are given. The proposed solution is also compared with the traditional ones in terms of energy costs, energy density, environmental sustainability, safety, ease of transport, future perspectives, and innovation level.
Given the significant energy consumption imputable to buildings, the development of accurate models to predict building energy performance to understand their environmental impact has become a ...fundamental research issue. In this paper, a method for evaluating a building's energy performance by enlarging the assessment perspective from a single building to a network of buildings is proposed and applied. The purpose of this research was to establish how a combined Inter-Building Effect (IBE) on energy consumption could work and how it could condition buildings' energy performance when there are close spatial relationships among buildings. To examine this, a simulation of the energy performance of a whole network of buildings represented by a realistic block of twenty single-family homes subject to different climatological contexts was conducted. The results demonstrate that buildings can mutually impact the energy dynamics of other buildings and that this effect varies by climatological context and by season. The IBE analysis and the specific proposed methodology revealed energy requirement modeling inaccuracies of up to 42% in summer (in Miami, FL) and up to 22% in winter (in Minneapolis, MN). These findings demonstrate that in order to accurately predict the energy performance of a single building, the IBE created by the spatial relationship with surrounding buildings should be considered.
► We simulate the energy performance of a realistic block of residential buildings. ► We study buildings' mutual impact on energy requirement in different climates. ► We propose a systematic method for assessing this effect: the Inter-Building Effect. ► We find important energy requirement modeling inaccuracies if IBE is neglected. ► IBE must be considered in order to accurately predict building energy performance.
The extreme effects of urban heat island (UHI) on energy consumption, air quality, and human health are significantly detrimental. Increasing the albedo of urban surfaces has been proposed as a ...potentially efficient mitigation strategy. In this study the Weather Research and Forecasting (WRF) mesoscale model has been used to simulate the urban climate of Rome (Italy).Four different scenarios have been analyzed: the Base Scenario as control case; the Base-ALB Scenario, in which the albedo of roof, walls and road have been increased; the Morph Scenario in which the morphology of urban area has been parameterized more accurately; the Morph-ALB Scenario in which the urban albedo of the improved model has been increased.
This study demonstrates that a more accurate parametrization of the urban morphology leads to a more accurate representation of UHI phenomenon. The simulation results show that albedo increase leads to the decrease of the 2-m air temperature at day-time and at night-time. Albedo increase offers very promising results in terms of UHI mitigation, reducing the temperature in the urban area by up to 4°C at daytime and a little increased (up to 1°C) in some locations at night time, compared to the control cases.
Urban heat island is an anthropogenic phenomenon affecting urban outdoor thermal comfort conditions and energy utilization. This is even truer in urban canyon configurations, characterized by low sky ...view factor and where the effect of short-wave and long-wave solar radiation on construction surfaces is able to produce massive outdoor local overheating. Traditional solutions cannot always be applied in urban historical canyons, where the exteriors of buildings cannot be modified due to preservation. Here, the capability of innovative cool materials to mitigate local microclimate of historical urban canyons is investigated. A preliminary experimental characterization of the materials is performed. A numerical simulation of the microclimate effect generated by the application of such materials is performed. Results show that the proposed materials improve the microclimate without neglecting preservation constrains. Such materials set the best scenarios in terms of thermal comfort, by enhancing albedo on canyon surfaces. Their application on the vertical surfaces of narrow canyons can lead to deleterious effects on outdoor thermal comfort. Such findings are confirmed by PMV and MOCI analyses. Energy efficiency solutions may be effectively implemented in historical districts, opening the doors to other tailored solutions, such as integrated renewables, to make these environments more sustainable and comfortable.
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•Urban canyon microclimate in historical districts is investigated and mitigated.•Novel cool materials for energy saving and outdoor comfort are implemented.•Radiative heat is reduced and more comfortable environment is achieved.•Energy efficient historic districts may deliver “green” message to the society.
The impacts of the urban heat island (UHI) phenomenon on energy consumption, air quality, and human health have been widely studied and described. Mitigation strategies have been developed to fight ...the UHI and its detrimental consequences. A potential countermeasure is the increase of urban albedo by using cool materials. Cool materials are highly reflective materials that can maintain lower surface temperatures and thus can present an effective solution to mitigate the UHI. Terni’s proven record of high temperatures along with related environmental and comfort issues in its urban areas have reflected the local consequences of global warming. On the other hand, it promoted integrated actions by the government and research institutes to investigate solutions to mitigate the UHI effects. In this study, the main goal is to investigate the effectiveness of albedo increase as a strategy to tackle the UHI, by using the Weather Research and Forecasting (WRF) mesoscale model to simulate the urban climate of Terni (Italy). Three different scenarios through a summer heat wave in the summer of 2015 are analyzed. The Base Scenario, which simulates the actual conditions of the urban area, is the control case. In the Albedo Scenario (ALB Scenario), the albedo of the roof, walls and road of the whole urban area is increased. In the Albedo-Industrial Scenario (ALB-IND Scenario), the albedo of the roof, walls and road of the area occupied by the main industrial site of Terni, located in close proximity to the city center, is increased. The simulation results show that the UHI is decreased up to 2 °C both at daytime and at nighttime in the ALB and in ALB-IND Scenarios. Peak temperatures in the urban area can be decreased by 1 °C at daytime, and by about 2 °C at nighttime. Albedo increase in the area of interest might thus represent an opportunity to decrease the UHI effect and its consequences.
The highest challenge of energy efficiency of building stock is achieving improved performance in existing buildings and, especially, in heritage buildings which per se are characterized by massive ...limitations against the implementation of the most sophisticated solutions for energy saving. In Italy, historical buildings represent more than 30% of the building stock and the vast majority require energy retrofit, while ensuring the preservation of the heritage value and acceptable comfort conditions. In this context, historical buildings must be retrofitted and re-functioned by introducing innovative technologies aimed at reducing energy consumption and improving human comfort, health, and safety. To this aim, this study implements the Historic Building Information Modeling (HBIM) approach for the integrated modeling, monitoring, management, and maintenance of a novel geothermal system involving horizontal ground source heat exchangers (GHEXs) coupled to an adsorption heat pump for the energy refurbishment of historical buildings. In detail, a rural building part of a medieval complex in Perugia, Central Italy, is considered as a pilot case study. The analysis stresses the potential of the Facility Management (FM) applications of HBIM to provide a tool for the human-centric operational management control of the building energy performance and indoor comfort when combined with the building monitoring and supervision system. Therefore, this integrated HBIM approach may drive the path towards the user-centric re-functioning of heritage buildings.
Cool roofs represent an acknowledged passive cooling technique to reduce building energy consumption for cooling and to mitigate urban heat island effects. This paper concerns the evaluation of the ...dynamic effect of new cool roof clay tiles on building thermal performance in summer and winter conditions. To this end, these properties have been analyzed on traditional roof brick tiles through an indoor and outdoor two-year long continuous monitoring campaign set up in a residential building located in central Italy. The analysis and the cooperation with industrial companies producing brick tiles and reflective coatings allowed the production of a new tile with notable "cool roof" properties through the traditional industrial manufacturing path of such tiles. Notable results show that during summer the high reflection tiles are able to decrease the average external roof surface temperature by more than 10 degree C and the indoor operative temperature by more than 3 degree C. During winter the average external surface temperature is lower with high reflection tiles by about 1 degree C. Singular optic-thermal phenomena are registered while evaluating the dynamics of the cool roof effect. Interesting findings show how the sloped cool roof application could suggest further considerations about the dynamic effect of cool roofs.
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