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This paper presents the experimental design-to-installation process of two textile hybrid window screens, aimed at mitigating the comfort conditions and preserving the frescoes of Sala delle Asse a...

The pattern and permeability characteristics that compose three-dimensional (3D) textiles are important as a textile shading component to the architecture, engineering and construction (AEC) industry. Moreover, due to their complex geometry, 3D fabrics require a detailed modeling for correct evaluation of performance. This paper aims to present and investigate the optical properties of six 3D fabrics proposed as an alternative to traditional roller blind shading systems, which could guarantee high daylight availability and visual comfort. The light transmission distribution for the different samples has been characterized by carrying out angular visual transmittance measurements, using integrating sphere optical benches, and virtual modeling using Radiance's genBSDF tool. The Bidirectional Scattering Distribution Function (BSDF) calculated with Radiance shows a good fit with the optical angular measurements, which were used as a benchmark and to calibrate models. The performance of the 3D textiles, in terms of illuminance, daylight availability, and glare, was assessed considering two of the set of 3D textiles as alternative materials for a movable internal roller shade system in an open office. The innovative system was compared with a traditional single layer fabric roller blind under different shading control strategies, 3D fabrics demonstrate the potential of increasing Daylight Autonomy while providing better uniformity and better connection with the outdoors due to a higher openness factor. The shading effect created by the 3D geometry of the textile can increase the openness factor while restricting glare.

Citizens in dense built environments are susceptible to the simultaneous occurrence of Slow Onset Disaster (SLOD) events, being particularly prone to increasing temperatures and air pollution. Previous research works have assessed these events&rsquo, arousal separately and have identified when their intensity is critical. However, few have integrated their analysis, possibly limited by the quality and granularity of available data, the accessibility and distribution of sensors, and measurements not emulating the surroundings of a pedestrian. Thus, this work performed an outdoor meso-scale multi-hazard-based risk analysis to study the aggregated effects of the SLODs mentioned above. The study was carried out to narrow down the time-frames within 2019 in which these two events could have affected citizens&rsquo, health the most. A weighted fuzzy logic was applied to superimpose climatic (temperature, humidity, wind speed, and solar irradiance) and air quality (particulate matter, ozone, and ammonium) distress (true risk) on an hourly basis, allocated using set healthy and comfortable ranges for a specific dense urban climate context within Milan (Italy), processing data from Milano via Juvara station. The findings show that sensitive groups were at risk of high temperature and pollution separately during 26% and 29% of summer and mid-season hours, respectively, while multi-hazard risk would arise during 10.93% of summer and mid-season hours, concentrated mainly between 14:00 and 20:00.

Urban climates are highly influenced by the ability of built surfaces to reflect solar radiation, and the use of high-albedo materials has been widely investigated as an effective option to mitigate urban overheating. While diffusely solar reflective walls have attracted concerns in the architectural and thermal comfort community, the potential of concave and polished surfaces, such as glass and metal panels, to cause extreme glare and localized thermal stress has been underinvestigated. Furthermore, there is the need for a systematic comparison of the solar concentration at the pedestrian level in front of tall buildings. Herein, we show the findings of an experimental campaign measuring the magnitude of the sunlight reflected by scale models reproducing archetypical tall buildings. Three 1:100 scaled prototypes with different shapes (classic vertical façade, 10% tilted façade, curved concave façade) and different finishing materials (representative of extremes in reflectance properties of building materials) were assessed. A specular surface was assumed as representative of a glazed façade under high-incidence solar angles, while selected light-diffusing materials were considered sufficient proxies for plaster finishing. With a diffusely reflective façade, the incident radiation at the pedestrian level in front of the building did not increase by more than 30% for any geometry. However, with a specular reflective (i.e., mirror-like) flat façade, the incident radiation at the pedestrian level increased by more than 100% and even by more than 300% with curved solar-concentrating geometries. In addition, a tool for the preliminary evaluation of the solar reflectance risk potential of a generic complex building shape is developed and presented. Our findings demonstrate that the solar concentration risk due to mirror-like surfaces in the built environment should be a primary concern in design and urban microclimatology.

In the last few years, the technology re-evolution has deeply transformed several aspects of everyday life. For sure, one technology with a strong impact is the so-called Internet of Things (IoT). The IoT paradigm made it possible to break down the data barrier between the vertical domains on which the traditional information and communication technology (ICT) world was organized. Recently, the designers of home automation systems have begun looking to the IoT paradigm to ease the deployment of systems that are able to collect data from different plants. Such a situation has driven further evolution from the traditional automation system, where logic is defined by the programmer or by the user, to a cognitive system that is able to learn from the user&rsquo, habits regarding what should be the best configuration of plants. Several countries are funding renovations of public and private buildings for improving energy efficiency. Generally, such renovations are only focusing on the structure of the building and of its energy performance (e.g., the thermal envelope, window units, air-conditioning plants, and renewable generators) and largely ignoring the use of intelligent devices. On the contrary, scientific literature and practice have demonstrated that the wider use of IoT sensors, as well as distributed and remote intelligence, is fundamental to optimize energy consumption. This research work aimed to identify issues due the application of cognitive solutions during the renovation phase of buildings. In particular, the paper presents a cognitive architecture to support the operation and management phases of buildings, thanks to the massive digitalization of the entire supply chain of the construction sector from the single building element to the entire construction process. Such an architecture is capable of combining data from the IoT sensors and actuators of smart objects installed during the renovation phase, as well as legacy building automation systems. As an indication of the capability of the proposed solution, an intelligent window device was developed and validated. Within the Energy, Life Styled, and Seismic Innovation for Regenerated Buildings (ELISIR) project, window units are equipped with sensors to monitor indoor and outdoor condition behaviours of users. In addition, windows are able to react to changes in the environment by means of actuators that enable motorized opening and shading. Thanks to the cognitive layer designed in the project, the window is able to automatically define the best rules for opening and shading by using the local controller to satisfy user&rsquo, s habits and energy efficiency targets. The cognitive layer defines the appropriate rules for opening and shading using the decision tree algorithm applied to the data generated by the sensors in order to infer users&rsquo, preferences. For this research, two prototypes of the window units were installed in two offices of Politecnico di Milano, Italy. The accuracy of this algorithm to classify the users&rsquo, behaviour and preferences was found to be around 90%, considering an observation interval of two months.

Green roofs are a resource for the city: they mitigate pollution, decrease the urban heat island effect (UHI), and regulate storm runoff. Within a climate change scenario, green roofs might instead become an issue, and in particular, in mitigating UHI at mesoscale level. The aim of the contribution is to define the water balance and thus the water consumption of a typical green roof, considering its variation when immersed into different climate scenarios that took place in the past five years (Linked with the following research projects: (1) Research title: 2016, Fondazione Minoprio/Politecnico di Milano, Dipartimento ABC (ongoing), Research type: Convention, Responsible: Matteo Fiori. (2) Research title: 2018, Harpo Contract (ongoing), Research type: Funded by third parties, Responsible: Matteo Fiori. (3) Research title: 2018, Soprema Contract (ongoing), Research type: Funded by third parties, Responsible: Matteo Fiori. (4) Research title: 2018, ASSIMP T-dry Contract (ongoing), Research type: Funded by third parties, Responsible: Matteo Fiori).

Sensing technologies integration in buildings has grown rapidly. Most of them are connected to platforms for monitoring data and notifying anomalies, but few are integrated within building elements (either for data collection or response). These technologies help regulate HVAC, or detect building systems’ failures, but few enable passive sustainable strategies or space maintenance. It is possible to enhance building responsive operation by gathering granular data on passive systems’ operation and space occupation by setting a building component, that houses a sensor network. That is, if plugged into Building Information Models, it permits adaptation to unusual climate conditions or abrupt space use [Linked with the following correlated research projects: Research title: 2017, ELISIR. R&D+S&I Smart Living, R.L 26/2015 Widespread creative and technological manufacture 4.0 (ongoing) Research type: Funded by Regione Lombardia Responsible: Tiziana Poli (research unit, Politecnico di Milano).].

Indoor occupant comfort has been related to total building energy consumption, and some of its components (lighting, heating, and cooling mainly), together with carbon production, also with occupants’ productivity, learnability, and health. However, few works relate comfort to the circular economy and are barely related to the circularity of the selected building materials or systems. This work is intended to evaluate how the dynamism of a building envelope (triggered by different comfort preferences) disturbs the efficiency of the building and maintenance activities (Linked with the following correlated research projects: (1) Research title: Imaging processing on determining eye strain (ongoing), Participant research groups: VELUXlab & SEEDLab.ABC).

Wall finishes with high solar reflectance and thermal emittance, commonly known as cool walls, can reduce the exterior surface temperatures of façades, and consequently the building cooling energy needs and power demand, and lower the sensitivity to degradation. Aging, though, may affect their performance. To investigate this risk, we exposed for four years in Milan, Italy, two series of façade finish coats, white and beige, facing north and south, in vertical and vertical-sheltered position, and we measured their solar spectral reflectance and thermal emittance before and after aging. The solar reflectance of the white finish coats drops from 0.75 to 0.55 in four years, and from 0.46 to 0.38 for the beige coats, while the thermal emittance is unchanged. Then, for a typical residential building with white walls, we computed that the cooling energy needs increase with walls aging by 5% and 11%, respectively, with or without exterior wall insulation. The exterior surface temperature is increased even by 6 °C, and the number of sudden surface temperature variations in one hour is boosted. Finally, the moisture content in the external layers is reduced, showing the impact on the heat and mass balance because of the uncertainty in solar absorption due to aging. © 2017 Elsevier B.V.

Indoor Environmental Quality (IEQ) is a key issue in the design and renovation of any indoor building environment. It is comprised of different aspects (e.g. visual, thermal, acoustic comfort, etc.), which directly affect the building occupants’ wellbeing. Studies on this topic have grown rapidly in recent years, as the time that occupants spend indoors is increasing. In this regard, indoor luminous conditions are crucial for providing sufficient task illuminance as well as to stimulate the human circadian system. Insufficient lighting conditions have been proven to be related with reduced productivity/learnability, mood swings and health disorders, thus emphasizing the necessity for further research in this field. Therefore, proper performance evaluation criteria for managing and optimizing lighting spectral composition is needed. For instance, indoor lighting conditions can be evaluated by quantity, intensity, and/or uniformity, but also by spectral content, which determines the energy conveyed and the level at which the human body is stimulated. This spectral content can vary depending on the preferred or prevalent light source, interior finishes and glazing properties generating a singular indoor lighting environment. Thus, a preliminary study on the variation of the indoor daylight spectral content is conducted using a scaled model, applying various glazing types and interior finishes. Then, daylight simulations are performed on a calibrated virtual model to evaluate the effect of various environmental conditions. Results show a considerable impact of the interior finishes as well as glazing type on the attained circadian potential of studied indoor environment.

Green roofing is a sustainable solution for building energy saving, urban heat island mitigation, rainwater management and pollutant absorption. The effectiveness and performance of green roofs depend on layer composition and properties. The uncertainties surrounding green roof performance modeling are mainly related to the vegetation and substrate layer, which are subjected to surrounding climatic conditions. Energy simulation software typically does not use validated models encompassing all possible combinations of vegetation layers and substrates. Therefore, the objective of this research is to investigate different extensive green roof solutions for assessing thermal performance and to provide information on vegetation and substrate layer design. Different simulations executed in EnergyPlus were carried out based on realistic literature data drawn from previous experimental tests conducted on plants and substrates. Several combinations (30 plant-substrate configurations, six vegetative species and five types of substrates) were defined and evaluated. Furthermore, indexes based on the surface temperatures of green roofs were used. Finally, a comprehensive ranking was created based on the scores to identify which extensive green roof combinations offered the highest performance. Greater plant heights, LAI values and leaf reflectivity values improve green roof energy performance in the summer more significantly than substrate modification. During the winter, thermal performance is more heavily dependent on the substrate if succulent vegetation is present, regardless of the substrate used. These results could provide designers with useful data at a preliminary stage for appropriate extensive green roof selection.

ETFE membranes are generally used in architecture for large roofing and facade systems, because of their transparency and lightness compared to glass alternatives. Multilayer ETFE panels are used to improve single membrane systems performances, reducing thermal losses, by the use of an air gap between two or more ETFE foils, generally serigraphed or surface treated to reduce solar gains. Surface temperatures and global solar radiation strongly affects mean radiant temperature (MRT), and comfort perceived by a user facing a transparent envelope as well as solar gains strongly influences primary energy use for cooling in summer conditions. In the following paper an alternative dynamic solar gains mitigation strategy is presented and applied to a double layer, non-cushions, ETFE panel for facades. We measured the effectiveness of a water spray system located in the air-gap between the parallel ETFE foils and used to reduce surface temperatures and solar access depending on different summer solar radiation values and outdoor/indoor air temperature conditions. Systems alternative with different in nozzle dimension, water spray geometry and water consumption were already tested to evaluate the best compromise between solar gains reduction and water use. The results are preliminary but we noticed that a reduction up to the 10% of the total solar gains could be achieved as well as a reduction of 10 °C of surface temperature. Comfort evaluation for a standard indoor space were already done.

Chemical and physical stress, weathering, organic and inorganic matter deposition, and microbial growth over time, or “aging”, affect the optical-radiative performance of building envelope materials. Natural exposure helps to quantify these effects, but it usually requires several years. Further, the contribution of the different degradation agents cannot be isolated, and results from different campaigns cannot be easily compared because of the variability in the boundary conditions producing aging. Here we present an adaptation of the protocol implemented by ASTM as D7897-18 “Standard Practice for Laboratory Soiling and Weathering of Roofing Materials to Simulate Effects of Natural Exposure on Solar Reflectance and Thermal Emittance”. The aim is to reproduce in the laboratory the changes in albedo (solar reflectance) and thermal emittance experienced by building envelope materials in European urban areas rather than in the United States. We tuned the spraying duration and weathering cycles, and we compared the UV–vis–NIR reflectances of naturally-aged specimens (48 months in Rome and Milan) of roofing and wall finish materials to those exposed to laboratory weathering and soiling. Excluding those materials that show early physical-chemical degradation, the mean absolute deviation between natural and laboratory exposure of roofing products is equal to 0.027 in albedo. This is a lower value than the differences between two natural exposure campaigns at the same site. We clearly defined the limits of application of the protocol, providing an appraisal of the repeatability of natural aging. Moreover, we identified possible improvements in the methodology to conduct both natural and laboratory exposure.

The aim of this paper is to explore lean retrofit strategies for transparent envelope of existing Italian office buildings, to improve their performance and to ensure low energy use and a good thermal and visual comfort.Solar and light control is necessary to prevent overheating in office buildings those generally present high internal loads. The effectiveness of solar window films use in Italian buildings context is here investigated, in comparison with other strategies like the use of internal roller blinds and the substitution of the existing window panes with high performance ones. A sensitivity analysis was assessed to evaluate the office unit primary energy use under different retrofit solution, weather conditions and window to wall ratio. A conventional existing office unit was modeled in EnergyPlus and LBNL Radiance to assess heating, cooling and lighting energy demand coupled with visual comfort parameters. Thermal comfort was evaluated hourly in accordance with ISO 7730. The results are presented with a cost - benefit analysis to understand the best retrofit solution.

The reduction of the energy use of buildings at the urban scale represents a key research and design topic with the purpose of developing specific methods for saving energy in buildings. These methods are often focused on the analysis of building thermal-energy behavior by considering the building as a stand-alone object. In this perspective, the thermal-energy behavior of two buildings in New York City is evaluated in this paper with varying urban contexts, in order to evaluate the Inter-Building Effect (IBE). The IBE analysis shows that the inaccuracy in neglecting the urban context in building modeling varies from 9.6 percent, to 71.9 percent. These results confirm that, in order to make accurate predictions about building thermal-energy performance in real urban contexts through dynamic simulation, the interaction between the building and the urban surrounding should be taken into account, in particular in dense urban areas.

Metal mesh grids and perforated screens are used in new and renovated buildings as an external second skin for the building envelope; to enhance architecture design, to filter daylight and to reduce solar gains. Their effectiveness as shading devices depends on their geometry, texture and application. In the first part of the paper six types of shadings with similar transparencies, depending on geometry and openness factor of metal mesh grid and perforated screen, were investigated. Integrating sphere measurements were collected to obtain spectral optical properties of the shading devices. The optical properties were measured for incidence angles between normal and 60°with a step of 15°. The data collected were integrated to obtain visible and solar transmittance values in accordance with ISO 9050. In the second part of the paper a parametric study on spacing and thread dimension of metal mesh grids was done using Window 6.2 models to evaluate their shading potential, defining annual different shading profiles depending on shading geometry, latitude and orientation. A conventional office unit with a curtain wall facade with a metal mesh grid shading system was modeled in TRNSYS to evaluate the solar gain profiles and their effects on the energy balance of the office unit, under different weather conditions.

Urban areas are characterized by a plurality of microclimates given by the diversity of morphologies, optical and radiative properties, solar access and air circulation in different street canyons. For these reasons, beyond strategies at urban scale, mitigation needs to be addressed at district or even at urban canyon scale, just like the design of buildings. Among different options, canopy shading has been proposed in several urban contexts, and to assess the impact of this mitigation technique on air temperature and outdoor thermal comfort conditions we performed numerical simulations for a north-south oriented urban canyon with high solar access (height to width ratio equal to 0.18) in the climate context of Milano (Italy).

Cities often show nighttime air temperatures higher by 3–4 °C than adjacent non-urban areas. This yields to cooling loads in average higher by 13% for urban than rural buildings. Here we assess the hygrothermal performance and the heating and cooling loads of a reference building representative of the Italian stock. We compare its performance calculated with hourly urban weather data (2002–2008) with the performance of the same building using a rural dataset instead. Milan’s Urban Heat Island reduces the heating loads by 12% and 16%, for the non-insulated and insulated building, respectively, while the cooling loads are increased by 41% and 39%. The urban building also shows dehumidification loads 74–78% lower than the rural building. Moreover, during the 2003 heat wave, the indoor air temperature is computed to be 1.5 °C–2.2 °C higher in a non-conditioned urban building than in the rural one. This increases the wakefulness, occupants’ vulnerability to overheating, and impacts the overall hygrothermal performance. Our findings highlight the need of a different design concept for urban with respect to non-urban buildings, even though they are, by law, in the same climate zone.

This paper aims to show a new solar design tool that can be used to optimize the building's shape and solar access in existing urban areas. The presented methodology was used for the analysis of the Surfers Paradise in Queensland, where in the past the urban and buildings development changed completely the morphology of the city. Since in the medium term the Zero Energy building will be the standard for new constructions, urban development should follow the Integrated Sustainable Design approach and the principles of solar design in order to exploit solar radiation using PV modules and Solar thermal collectors in the building envelopes. The tool is based on Matlab algorithm and on RADIANCE-DAYSIM, a dynamic simulation tool, and can help urban designers and architects since the first design phase.

This paper presents an approach to measure, characterize and simulate photometric performances of light transmission efficiency of an innovative transparent concrete panel for facades. The transparency was obtained by a texture of PMMA resin insertions in the fiber reinforced concrete panel. In the first part of the paper integrating sphere measurements were collected to derive spectral optical properties of the panel. The optical properties of a specimen were measured for incidence angles between normal and 60° and the spectral results were reported. The data collected during the measures were used to: create and validate a simplified Radiance model of the panel and to optimize simulation parameters to estimate properly the total internal reflections effects thought the PMMA resin insertions.

This paper shows the results of a research aimed at assessing the amount of energy that can be produced by solar envelopes (facades and roofs) in urban contexts. A preliminary set of simulations was carried out, through dynamic yearly analyses on a sample building, to identify the main parameters influencing the availability of solar radiation and to optimize the building’s shape. The general target is to maximise solar radiation available on the external building envelope, in order to exploit it through building integrated solar systems. Furthermore, the effect of reflected solar radiation has been analysed by simulating different finishing materials (green facades, glazed facades, concrete facades and aluminium facades) on the neighbouring buildings. © 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of PSE AG

Building envelope materials containing titanium dioxide have been proposed to exploit their photoactivated depolluting and self-cleaning potential, but a full appraisal of their durability and long-term performance is still missing. This study reports a two-year campaign of natural exposure in Milano, Italy, of photoactive and non-photoactive fiber-reinforced mortars, analyzing the evolution of lightness, solar reflectance, porosity and photoactivity. After aging, photoactive samples showed limited color variation. The photocatalytic activity of TiO2 containing samples, characterized with dye degradation tests, was minimal after aging. Then, after alternated cycles of UV-Vis irradiation and rinsing, almost 70% of the initial photocatalytic efficiency was recovered. © 2015 Published by Elsevier Ltd.

Windows are the most important part of the building façade to control solar gains, thermal losses and visual comfort. Office buildings usually have medium-high WWR (window to wall ratio value) and high internal gains (due to users, lighting and appliances). For this reason, they require a good balance between thermal and visible performances of transparent façades and shading control strategies to avoid overheating, optimizing daylighting aspects. A sensitivity analysis was assessed to evaluate primary energy use for heating, lighting and cooling for conventional Italian single office units equipped with static metal mesh shading devices with different geometries and openness factor values. Different location (Milan, Palermo), orientation (south and west) and WWR (33% and 100%) were analyzed. Hence shading devices alternatives as venetian blinds and sun control windows are proposed as a comparison. © 2015 The Authors.

This paper is divided in two sections. The first section present the measurement and evaluation of soiling effects of spectral light and solar transmittance decay of Ethylene Tetrafluoroethylene Copolymer (ETFE) membranes after three and six months of exposure in Milano city outdoor urban conditions, with different tilt and orientation. The obtained values where use to compute thermal and solar properties of a multilayer ETFE panel. The second section presents the results of an experimental campaign for measuring thermal transmittance of a non-pneumatic and non-cushion shape double layer ETFE sample panel realized with two membranes parallel to each other and tensioned on a frame. The thermal transmittance measurement reflects ISO 9869 measurement approach combined with the use of a thermographic camera to evaluate surface temperatures over the sample panel.

Highly reflective roofs, widely known as cool roofs, can reduce peak surface temperatures and the energy required to cool buildings, mitigate urban microclimates, and offset CO 2 . However, weathering, soiling, and biological growth affect their solar reflectance. In this study, the solar spectral reflectances of 12 roofing membranes were measured before the exposure and after 3, 6, 12, 18, and 24 months of natural ageing in Roma and Milano, Italy. The membranes with an initial solar reflectance greater than 0.80, for example, decreased in reflectance by 0.14 in Roma and 0.22 in Milano after two years. Then, for a typical highly insulated commercial building, the annual cooling load savings were calculated to be reduced by 4.1–7.1 MJ m −2 y −1 per 0.1 loss in reflectance. When the buildings are non-insulated, the savings reduction is 58–71 MJ m −2 y −1 in Milano and 70–84 MJ m −2 y −1 in Roma. Ageing yielded a reduction of the cooling load savings that could be achieved with a new white membrane of 14–23% in Roma and of 20–34% in Milano. Moreover, in Milano, an aged, white, highly insulated roof, which has a solar reflectance of 0.56, may reach a surface temperature 16 °C higher than a new roof, which has a solar reflectance of 0.80.

In a scenario where renewable energies will play a foreground role, a reliable forecast of the energy production of such sources, like solar radiation, is a requirement for managing smart grids. However, the ability to predict the possibility to produce sustainable energy in different climatic conditions can be very useful for many other purposes (e.g., for Climate Sensitive Buildings). This is particularly true when working with climatic data that are, as a matter of fact, highly unsteady. Nevertheless, the use of data collected in the past can help to face the daily and seasonal variability. An algorithm for illuminance prediction based on Support Vector Regression (SVR) is here proposed and the results are presented and discussed.