Comparing the thermal performance of Living Lab monitoring and simulation with different level of input detail

Dynamic envelope solutions are critical to achieve comfort conditions minimizing the need of active air conditioning systems, emphasizing the potential of thermal adaption of the building occupants. Dynamic systems are, however, difficult to be implemented in European building energy certification schemes, based on semi-stationary calculation method, standard uses and reference boundary conditions. In the attempt to develop a flexible and dynamic method able to reduce the performance gap between real and expected performance, this paper presents the comparison between measurements and simulations of a Living Lab office operated in thermal free floating, with different strategies for the solar protection and the night ventilative cooling. Simulations were performed using the dynamic platform PREDYCE, which allows for manipulating monitored and simulated data. The first phase was dedicated to the model calibration using the indoor air temperature as relevant indicator against monitored data. The coefficient of variation of the root mean squared error is in the 8-9% range. Building simulations of the calibrated model demonstrated a large variation of the results as a function of the input data, with increase of discomfort hour up to a factor 20 and a reduction of discomfort hours up to 95%

Set-up and Calibration by Experimental Data of a Numerical Model for the Estimation of Solar Factor and Ug-value of Building Integrated Photovoltaic Systems☆

Abstract The acronym BIPV (Building Integrated Photovoltaics) refers to the installation of photovoltaic systems which, in addition to convert solar energy into electrical energy, have a high level of architectonical integration with the built environment, becoming a real architectural cladding to be installed over the buildings in place of traditional envelope systems. Many typologies of BIPV have been developed, however their thermal characteristics such as g and Ug-value are not well evaluated and require more detailed analyses considering that they could replace large extension of traditional building envelope. A first approach to address this problem is proposed in this work. A mathematical model based on a finite differences scheme for the estimation of the thermal parameters g and Ug-value has been developed and tuned using experimental value measured on sample BIPV with a Hot Plate and a Solar Calorimeter. The results of the model show that the introduction of solar cells in a laminated glass or in a double glass leads to a reduction of energy parameters modifying winter and summer energy balance of the building system

Effects of soiling and weathering on the albedo of building envelope materials: Lessons learned from natural exposure in two European cities and tuning of a laboratory simulation practice

Chemical and physical stress, weathering, organic and inorganic matter deposition, and microbial growth over time, or \u201caging\u201d, 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 \u201cStandard Practice for Laboratory Soiling and Weathering of Roofing Materials to Simulate Effects of Natural Exposure on Solar Reflectance and Thermal Emittance\u201d. 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\u2013vis\u2013NIR 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 'Moon Mapping' project to promote cooperation between students of Italy and China

The research project 'Moon Mapping' has been established in 2014 between the Italian and Chinese Governments to promote cooperation and exchange between undergraduate students from both countries. The operational phase of the project started in early 2015, and will end in 2017, for a total length of three years. The main aim is to train new scholars to be able to work on different kinds of remotely-sensed data collected over the Moon surface by the Chinese space missions Chang'E-1/2. The project coordination has been assigned to the Italian Space Agency for the Italian side and to the Center of Space Exploration, China Ministry of Education, for the Chinese side. Several Chinese universities and Italian national research institutes and universities have been officially involved in this project. Six main research topics have been identified: (1) map of the solar wind ion; (2) geomorphological map of the Moon; (3) data preprocessing of Chang'E-1 mission; (4) map of element distribution; (5) establishment of 3D digital visualization system; and (6) compilation and publication of a tutorial on joint lunar mapping

DART Impact Ejecta Plume Evolution: Implications for Dimorphos

The NASA Double Asteroid Redirection Test (DART) spacecraft impacted the moon Dimorphos of the [65803] Didymos binary system and changed the binary orbit period, demonstrating asteroid deflection by a kinetic impact and indicating that more momentum was transferred to Dimorphos by escaping impact ejecta than was incident with DART. Images of the DART impact ejecta plume were obtained by the Light Italian cubesat for Imaging of Asteroids (LICIACube) in the first few minutes after the DART impact. The ejecta plume imaged by LICIACube 158 s after the DART impact prior to closest approach shows no evidence for plume clearing at low altitude. The ejecta plume imaged 175 s after the DART impact is optically thick up to projected altitudes of 200 m above the surface of Dimorphos. These observations are compared with models of the impact ejecta plume optical depth, structure, and evolution, which are developed from point-source scaling models fitted to numerical simulations of the DART impact into a rubble pile Dimorphos with different material strengths. The observations of the impact plume optical depth and the high momentum transfer from the DART impact are not consistent with impact and ejecta plume models assuming the Dimorphos cohesive strength to be as high as 5000 Pa. Models with 5 and 50 Pa Dimorphos cohesive strength provide the overall best consistency with plume opacity observations and high momentum transfer

DART Impact Ejecta Plume Evolution: Implications for Dimorphos

The NASA Double Asteroid Redirection Test (DART) spacecraft impacted the moon Dimorphos of the [65803] Didymos binary system and changed the binary orbit period, demonstrating asteroid deflection by a kinetic impact and indicating that more momentum was transferred to Dimorphos by escaping impact ejecta than was incident with DART. Images of the DART impact ejecta plume were obtained by the Light Italian cubesat for Imaging of Asteroids (LICIACube) in the first few minutes after the DART impact. The ejecta plume imaged by LICIACube 158 s after the DART impact prior to closest approach shows no evidence for plume clearing at low altitude. The ejecta plume imaged 175 s after the DART impact is optically thick up to projected altitudes of 200 m above the surface of Dimorphos. These observations are compared with models of the impact ejecta plume optical depth, structure, and evolution, which are developed from point-source scaling models fitted to numerical simulations of the DART impact into a rubble pile Dimorphos with different material strengths. The observations of the impact plume optical depth and the high momentum transfer from the DART impact are not consistent with impact and ejecta plume models assuming the Dimorphos cohesive strength to be as high as 5000 Pa. Models with 5 and 50 Pa Dimorphos cohesive strength provide the overall best consistency with plume opacity observations and high momentum transfer

Resilient cooling strategies – A critical review and qualitative assessment

The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out

Moon Mapping Project: un progetto di cooperazione scientifica in ambito spaziale tra Italia e Cina

Il programma “Joint Lunar Map Drawing Project by Chinese and Italian College Students”, noto come Moon Mapping Project, rappresenta un’importante iniziativa di cooperazione scientifica tra Italia e Cina, finalizzata al coinvolgimento diretto degli studenti dei due Paesi nella creazione di mappe tematiche della Luna attraverso l’elaborazione di dati acquisiti dai satelliti cinesi Chang’e-1 e Chang’e-2. Il progetto triennale, iniziato nel 2015, è inserito nell’accordo bilaterale siglato dal Ministry of Science and Technology, P.R. China (MOST) e dal MIUR, coordinato dall’ASI per l’Italia e dal National Remote Sensing Center of China. La parte italiana coinvolge 11 università e centri di ricerca e da parte cinese sono coinvolte 8 università e centri di ricerca. A seguito di una serie di visite presso le strutture di ricerca italiane e cinesi, che hanno permesso di conoscere nel dettaglio le attività che si svolgono nelle sedi del progetto, sono stati delineati 6 temi di ricerca, coordinati in modo congiunto da parte italiana e cinese. Le prime attività di ricerca hanno riguardato l’analisi dei dati resi disponibili da parte dei colleghi cinesi ed è stata estesa la piattaforma di condivisione web ASDC MATISSE (https://tools.asdc.asi.it/matisse.jsp). Da un punto di vista tecnico i dati cinesi devono essere considerati con un’attenzione particolare e necessitano di una fase di pre-trattamento importante a monte di un utilizzo operativo. Sono disponibili nel sito dati del sensore multispettrale IIM (Sagnac- based Imaging Spectrometer) e della camera CCD per la ricostruzione di immagini stereo per interpretazione in 3D. Queste prime attività hanno messo in evidenza diversi aspetti di sicuro interesse scientifico nell’ottica di un approfondimento dello stato di conoscenza della superficie lunare anche finalizzato 437 alle future missioni già previste nei programmi spaziali. Risulta inoltre di evidente interesse, anche nella sua complessità, il coinvolgimento diretto degli studenti provenienti da ambiti disciplinari e culturali diversi. Ulteriori informazioni sul progetto sono disponibili sul sito: http://solarsystem.asdc.asi.it/moonmapping

Evidence for multi-fragmentation and mass shedding of boulders on rubble-pile binary asteroid system (65803) Didymos.

Asteroids smaller than 10 km are thought to be rubble piles formed from the reaccumulation of fragments produced in the catastrophic disruption of parent bodies. Ground-based observations reveal that some of these asteroids are today binary systems, in which a smaller secondary orbits a larger primary asteroid. However, how these asteroids became binary systems remains unclear. Here, we report the analysis of boulders on the surface of the stony asteroid (65803) Didymos and its moonlet, Dimorphos, from data collected by the NASA DART mission. The size-frequency distribution of boulders larger than 5 m on Dimorphos and larger than 22.8 m on Didymos confirms that both asteroids are piles of fragments produced in the catastrophic disruption of their progenitors. Dimorphos boulders smaller than 5 m have size best-fit by a Weibull distribution, which we attribute to a multi-phase fragmentation process either occurring during coalescence or during surface evolution. The density per km2 of Dimorphos boulders ≥1 m is 2.3x with respect to the one obtained for (101955) Bennu, while it is 3.0x with respect to (162173) Ryugu. Such values increase once Dimorphos boulders ≥5 m are compared with Bennu (3.5x), Ryugu (3.9x) and (25143) Itokawa (5.1x). This is of interest in the context of asteroid studies because it means that contrarily to the single bodies visited so far, binary systems might be affected by subsequential fragmentation processes that largely increase their block density per km2. Direct comparison between the surface distribution and shapes of the boulders on Didymos and Dimorphos suggest that the latter inherited its material from the former. This finding supports the hypothesis that some asteroid binary systems form through the spin up and mass shedding of a fraction of the primary asteroid