1,721,087 research outputs found
A Mobile Vehicle-Based Methodology for Dynamic Microclimate Analysis
No full textAccurate monitoring is critical for better understanding cities’ microclimate conditions and safeguard citizens’ health. Previous studies have performed microclimate analyses of urbanized areas by implementing data from either stable meteorological stations or satellites, or by developing mobile stations. Here, we present a vehicle-based monitoring campaign capable of monitoring both the scalar and directionally dependent variables that regulate the canopy layer environment. Under this framework, we performed a monitoring campaign within an Italian city, and measured simultaneously air temperature (± 0.3 ∘C @ 20 ∘C), relative humidity (± 2% @ 20 ∘C), directional shortwave radiation (calibration uncertainty: < 1.8%), CO2 (± 50 ppm +2%) and PM10 (< 1%) concentration, wind speed (± 3% @ 40 m/s) and direction (± 3∘ @ 40 m/s), and specific location (latitude, longitude and elevation). The presented assessment can be carried out within almost any area that motorized vehicles are allowed to access (e.g. through public transportation vehicles). Its application together with other mobile stations that can specifically assess also pedestrian areas, such as footpaths, urban parks, sidewalks and bike paths, as well as fixed meteorological stations and remote sensing techniques can contribute to a better understanding of microclimate patterns and hence to more efficient urban planning and risk assessments
Investigation of CO2 variation and mapping through wearable sensing techniques for measuring pedestrians' exposure in urban areas
No full textHuman-centric microclimate analysis of Urban Heat Island: Wearable sensing and data-driven techniques for identifying mitigation strategies in New York City
No full textUrban heat island (UHI) is the best acknowledged climate-change related phenomenon also because it affects population health conditions in dense urban areas, even exacerbated during heat waves. While most of field studies are performed by means of permanent weather stations, this paper presents an intra-urban microclimate analysis through wearable sensing techniques for monitoring and characterizing granular peculiarities as perceived by urban pedestrians. The study is implemented in four areas of New York City presenting already mitigation techniques. These strategies are specifically analyzed from the pedestrians' perspective, who may walk along parks and sidewalks, to better study real boundary conditions responsible for thermal perception, even in those areas where vehicles are not allowed. A novel cluster analysis procedure is then carried out to perform data-driven identification of urban microclimate peculiarities in relation to its morphology (e.g. urban canyons etc.). Results show a non-negligible dependency from urban configuration both in winter and in summer. Measurements in the high-packed district winter daytime show a drop off of 0.6 °C in air temperature close to small parks. The packed low-rise district presents highest values of CO2, with respect to the other monitored areas both in winter and in summer. The same areas are automatically recognized through the data-driven clustering process. The data-driven approach may be therefore successfully integrated into classic measurements to investigate UHI and heat stress in dense anthropized areas
Intra-urban microclimate investigation in urban heat island through a novel mobile monitoring system
No full textMonitoring microclimate variables within cities with high accuracy is an ongoing challenge for a better urban resilience to climate change. Assessing the intra-urban characteristics of a city is of vital importance for ensuring fine living standards for citizens. Here, a novel mobile microclimate station is applied for monitoring the main microclimatic variables regulating urban and intra-urban environment, as well as directionally monitoring shortwave radiation and illuminance and hence systematically map for the first time the effect of urban surfaces and anthropogenic heat. We performed day-time and night-time monitoring campaigns within a historical city in Italy, characterized by substantial urban structure differentiations. We found significant intra-urban variations concerning variables such as air temperature and shortwave radiation. Moreover, the proposed experimental framework may capture, for the very first time, significant directional variations with respect to shortwave radiation and illuminance across the city at microclimate scale. The presented mobile station represents therefore the key missing piece for exhaustively identifying urban environmental quality, anthropogenic actions, and data driven modelling toward risk and resilience planning. It can be therefore used in combination with satellite data, stable weather station or other mobile stations, e.g. wearable sensing techniques, through a citizens’ science approach in smart, livable, and sustainable cities in the near future
Optimization of photoluminescent materials for lighting energy saving in the built environment
No full textIn the last decades, fossil fuels have become the primary resource for electricity generation, contributing to the aggravation of problems like global warming and ozone depletion. For this reason, innovative solutions are being continuously developed in order to improve energy efficiency in the construction sector. Beyond heating and cooling, urban lighting plays a significant role on the final energy consumption of a city, including both indoors and outdoors. In this work, photoluminescent materials are investigated as possible light sources to be implemented in urban lighting systems, focusing on the free-cost and renewable luminous gain they provide after being exposed to a proper radiation. In particular, commercially available photoluminescent powders are evaluated by means of spectroradiometric techniques and using a specifically designed experimental setup. Measurements are repeated for different intensities and wavebands of irradiation to identify the most promising “pigment-lamp” combination in terms of (i) luminous intensity and (ii) photoluminescence duration. Results show that the shorter the distance between the emission spectra of the exciting source and the photoluminescent powder, the better the performance of the latter. Therefore, the choice of both afterglow and exciting source cannot be independent from the final system's application and the required end-use lighting level
On kids' environmental wellbeing and their access to nature in urban heat islands: Hyperlocal microclimate analysis via surveys, modelling, and wearable sensing in urban playgrounds
No full textThe aim of this research is to investigate the environmental wellbeing of children in urban outdoor environments by developing and testing a new wearable device called the Baby c-air. Children are particularly vulnerable to environmental discomfort due to their physiological characteristics and lack of awareness about their own adaptation capabilities. This vulnerability can lead to childhood diseases and health issues, especially when exposed to overheating or continuous pollutants. Portable monitoring devices, such as the Baby c-air, can assess children's environmental exposure and provide timely information to limit their health risks.The study involved testing two prototypes of the Baby c-air under laboratory and in-field conditions to verify the accuracy of the device in collecting data. An experimental campaign involving 122 children was conducted in Italy during the summer, across four playgrounds. The option of integrating the COMFA-kid model for thermal comfort assessment was evaluated. The results indicated that microclimate peculiarities underline the importance of a human-centric approach for properly addressing environmental exposure. The discrepancies between thermal sensations provided by interviewed parents/tutors and predicted thermal sensations derived by the COMFA-kid model suggest that adults are generally weakly aware of children's thermal conditions.The Baby c-air can support children's adaptation potential and drive accompanying persons towards implementing conscious behaviors or moving to those areas with better environmental quality. The outcomes of this study can contribute towards urban outdoor design guidelines to improve children's well-being
Effect of time-of-day on human dynamic thermal perception
No full textImplementing heating and cooling set-point temperature modulations in buildings can promote energy savings and boost energy flexibility. However, time and time-of-day requirements in current indoor climate regulations are either overly simplified or ignored completely. A better understanding of how human thermal responses vary throughout the day is useful to effectively design and operate energy-flexible buildings. To date, only a handful of studies have looked at diurnal changes in thermal perception and mostly near steady-state neutrality without controlling for light exposure. This is the first experimental investigation aimed at understanding how the time of the day influences physiological and subjective human sensory responses to a localized dynamic thermal stimulus under constant light rich in long wavelengths (red). Results indicated that humans responded physiologically differently depending on the time of the day with a higher rate of change in the skin temperature in the evening compared with the afternoon. Furthermore, the increase of thermal sensation during the warming skin temperature transients was found to be greater in the evening. No differences were observed under steady-state thermal conditions. This evidence suggests that accounting for the time of the day is important when dynamically operating buildings, such as during demand-response programs
Subjective thermal response driving indoor comfort perception: A novel experimental analysis coupling building information modelling and virtual reality
No full textBuilding sector professionals, together with building physicists and human scientists, recognize the occupants' key role in determining final buildings energy needs. Occupants’ behavior is strongly influenced by their perception and represents a major variable affecting buildings' energy performance, but its impact is difficult to predict since the early design stage. This study proposes a new analysis framework and field test method to better comprehend and monitor people environmental perception and attitudes since the design stage, while stimulated through immersive environment modeled in a parametric platform, able to change every specific aspect of the future spaces. To this aim, a physical office room was re-designed through virtual reality (VR) and sense-of-presence feeling was registered, with a 76% of satisfaction rate. The VR designed environment was therefore used to reproduce key design variables without modifying the indoor thermal-energy environment during the experiment. Three triggers were simulated, i.e. glass filter, window aspect ratio, and artificial lighting color temperature. Both these two latter variables significantly produced placebo effects on most of the interviewed people, who declared to feel relatively hotter in high aspect ratio window conditions and low color temperature. As expected, non-thermal triggers may affect indoor thermal perception and, potentially, may induce better thermal satisfaction and energy saving behaviors, if properly considered. The proposed novel method can assist building design since the early stages, leading to low-cost and human-centric energy efficiency enhancements
Intra-urban microclimate mapping for citizens’ wellbeing: Novel wearable sensing techniques and automatized data-processing
No full textCities alter their-own climate due to their configuration and land surface thermal properties. The main effect is the well-known phenomenon of the Urban Heat Island (UHI) meaning higher temperatures experienced in urbanized environment with respect to rural surroundings. Nevertheless, thermal behavior of cities varies even within the city itself and the investigation of intra-urban microclimate diversification is of extreme importance in detecting the most critical conditions for citizens well-being and real building energy need estimation. This work wants to map the urban microclimate environment by means of a miniaturized and wearable weather station designed by the authors to catch the pedestrian perspective in the outdoors. Collected data are processed in order to erase elapsed-time-dependency of the observations collected through the mobile monitoring system and manual and automated data clustering procedure are compared to assess potential of the proposed automatized procedure in detecting peculiarities of the urban structure. According to results, the system demonstrates to catch the intra-urban microclimate diversification and the proposed data processing procedure gives back reliable results in terms of direct comparison of site specific environmental data and phisical drivers. Finally, the automatized clustering process produces better results for day-time monitoring in compact areas assuming temperature, relative humidity and solar radiation as environmental drivers
Influence of human behavior on cool roof effect for summer cooling
No full textCool roofs represent an acknowledged solution for cooling energy saving. However, the efficacy of such physical intervention can be affected by occupants' attitudes. Human behavior, in fact, is often neglected or underestimated at the design stage, e.g. while assessing the effect of physical retrofits. Accordingly, the purpose of this study is the assessment of cool roof effect with varying those occupants' attitudes having some effect on energy need for cooling and indoor Thermal Deviation Index (TDI). The analysis has been performed through calibrated dynamic simulation of a continuously monitored historic building. Innovative cool roof clay tiles, suitable for application in historic buildings, have been selected as physical retrofit. Main findings show that occupants' role can dominate the thermal-energy effect of the selected physical retrofit. For instance, cool roof tiles contribute to save 50% of primary energy for attic cooling in the hottest month, from 782kWh to 398kWh. If occupants' adaptation availability in adjusting temperature setups is taken into account in combination of the cool roof effect, the energy need for cooling becomes less than 100kWh. Also, the same cool tile is able to reduce the TDI from 0.87 to 0.54. If occupants are able to implement effective natural ventilation programs, TDI decreases to 0.29. These results show the necessity to consider neither only the effect of physical retrofits, nor only the effect of human attitudes, but the combination of both of them, in order to perform reliable energy need estimation, in both ante and post-occupancy assessment
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