Optimized Cool Coatings as a Strategy to Improve Urban Equivalent Albedo at Various Latitudes

This research study aimed to investigate the influences of angular-selective retro-reflective (AS-RR) and retro-reflective (RR) materials on the urban equivalent albedo (αeq). Full ray tracing solar analyses were conducted through the Monte Carlo-based numerical model validated in a previous work. Different geometry scenarios with different patterns of urban density were modelled. AS-RR and RR materials were alternately applied to the street and to the most irradiated façade. AS-RR materials were proposed to enhance the αeq of the urban environment particularly during summer. Solar analyses were reiterated for three latitudes (i.e., Oslo, Milan, Cairo). RR pavements and façades were capable of increasing the αeq throughout the year. However, implementing an angular-selective behavior allowed for a reduction of the mitigation potential of RR materials during the winter season. In their best application, RR and AS-RR materials enabled higher αeq in summer (122%) with negligible effects during the winter (7%). Finally, the study highlighted the need for exploiting numerical models capable of conducting full ray tracing solar analyses when investigating materials whose optical properties depend on the angle of incidence of the sunrays (such as RR materials)

Multi‐Stage Validation of a Solar Irradiance Model Chain: An Application at High Latitudes

Evaluating how the sources of uncertainty in solar modelling (e.g., input parameters, developed model chain) can influence the results’ accuracy is one of the main challenges when applied at high latitudes. In this study, a multi-stage validation workflow is implemented around five main stages: data acquisition, data quality check, solar radiation modelling, photovoltaic energy modelling, and experimental validation. Different data sources such as satellite observations, numerical reanalysis, and on-site ground measurements are considered as inputs, while the outcomes from each step of the model chain (e.g., decomposition modelling, transposition modelling, photovoltaic energy modelling) are compared against observations recorded from the solar radiation network at the Norwegian University of Science and Technology (NTNU-Solarnet) in Trondheim (Norway). In the first and second validation stages, the decomposition and transposition models with measured input parameters show the best accuracy indicators, but they do not fulfill the validation criteria. Conversely, in the third validation stage, the photovoltaic energy models with on-site ground measurements as inputs are experimentally validated. In conclusion, at high latitudes, the most accurate results are obtained when monitored solar irradiation data are used instead of satellite observations and numerical reanalysis. Furthermore, the shortest model chain is preferred, with equal data sources.publishedVersio

architectural and energy refurbishment of the headquarter of the university of teramo

Abstract The recent seismic events, which distressed the population of the Central Italy, have caused the incompliance with national safety standards of several historical buildings. In particular, the headquarter of the University of Teramo revealed some structural damages which make necessary to operate a restoration of the buildings. It represents a rare opportunity for investigating possible applications of a cluster of technologies and approaches largely recognized as efficient and high-performing to such particular buildings in order to achieve an upgrading in terms of energy efficiency. The proposal includes the improvement of the exploitation of renewable energy sources through adequate systems, which do not modify the visual perception of the pavilions. In that regards, the required electricity could be produced by a PV roofing installed on the parking area, while a biomass boiler and an absorption chiller could allow supplying the thermal and cooling needs. Furthermore, the rain water recovery system permits to reduce the exploitation of potable water for uses which do not require a high quality, such as irrigation. On the other hand, the envelope energy efficiency could be enhanced by applying passive strategies for reducing the heat losses ( winter conditions ) and gains ( summer conditions ) through facades and roof. The results confirmed the reliability of those interventions and the consequent advantages from an economical and energy point of view

The Influence of Icephobic Nanomaterial Coatings on Solar Cell Panels at High Latitudes

Solar energy’s penetration at high latitudes has been boosted during recent years, but snow deposits during the winter still limit its exploitation. Therefore, various solutions for snow removal, such as icephobic coatings, increasing panels’ tilt angle, and using wind flows, are being attempted to reduce snow and ice accumulation. The novelty of this study is that it presents insights into the snow-related issues of photovoltaic plants in Norway and proposes a preliminary approach to modelling these issues’ influences at high latitudes using a co-simulation approach. The workflow is based on a combination of PVsyst and Marion’s algorithm, and moves from the assessment of snow deposits on photovoltaic panels and the consequent reduction of plane of array (POA) irradiance (snow losses) to evaluating the influence of icephobic nanomaterials on snow losses. Solar analyses are performed on a photovoltaic plant located in Trondheim, Norway, and then reiterated considering the climate of the Norwegian cities of Bergen and Oslo. The snow losses between November and April, when the snow depth is greater than zero, are 32.75 kWh/m2 in Oslo, 25.05 kWh/m2 in Trondheim, and 5.85 kWh/m2 in Bergen. The application of icephobic coatings currently available on the market will reduce such snow losses to 12.05 kWh/m2 (65% efficiency) in Oslo, 10.00 kWh/m2 (60% efficiency) in Trondheim, and 3.35 kWh/m2 (45% efficiency) in Bergen. In conclusion, the application of icephobic coatings should be more greatly boosted in a continental climate (Oslo and Trondheim) than in an oceanic climate (Bergen) to maximize photovoltaic power output.publishedVersio

NTNU-SINTEF SolarNet: A solar irradiation monitoring network at high latitudes

This study presents a monitoring network for solar irradiation at high latitudes, called NTNU-SINTEF SolarNet. The network collects, with a time resolution ranging from seconds to hours, solar irradiance data, e.g. global horizontal irradiation, diffuse horizontal irradiation, direct normal irradiation, global tilted irradiation, solar energy generation, which are required in solar irradiation modelling in built environments. The network will be used for specific applications, such as (i) anomalies detection, (ii) influences of ground albedo, and (iii) ageing/degradation of solar modules, that are described in this paper. Some characteristics that make the NTNU-SINTEF SolarNet relevant for solar energy research at high latitudes are identified: short distances among the sensors, the ease of data accessibility, the use of the same sensor typologies, and different solar module technologies. The research holds the potential to boost the solar energy digitalization, impacting on several aspects such as predictive and adaptive control strategies for energy management, design of renewable energy system, multi-scale optimization and efficient exploitation of solar energy.publishedVersio

refugee camps as an opportunity for promoting alternative development strategies based on carbon credits

Abstract The difficult social issues faced by non-governmental organizations regarding planning, management, and evolution of the refugee camps led to evaluating alternative development strategies. Indeed, innovative technologies could be promoted for sustainably enhancing local economy. The present model suggests the exploitation of high-albedo materials to generate cool oases in hot climate contexts. The benefits derived by this proposal were investigated by simulating the application of high-albedo devices on shelters in Zaatari, then the avoided carbon emissions were quantified, and several scenarios were discussed. In the framework of the Emissions Trading System, the carbon credits, which can be obtained and sold by contributing to the global warming mitigation process, are estimated to be around 150,000 tons CO 2-eq . Considering the market tendencies presented during the COP21 in Paris, the intervention is demonstrated to be sustainable in economic and environmental terms. The payback period is estimated in 3 years in the most reliable scenario. The work presents the main results of a wider research that also included consideration about the urban planning of the camps

A Comparative Study on Opto-Thermal Properties of Natural Clay Bricks Incorporating Dredged Sediments

The brick industry is currently facing a shortage of natural resources. Despite this, the demand for construction bricks is progressively increasing. Alternative materials, such as dredged sediments and solid organic waste, have been recently proposed as options to replace natural clay in brick manufacturing. Potential exploitation of dredged sediments in clay bricks is evaluated in this study. The chemical composition of the mixtures and the opto-thermal properties of brick samples, which differed for the dredged sediment content (from 10% to 50% of the clay weight), were investigated. Chemical analyses detected lower concentrations of heavy metals in bricks incorporating dredged sediments (DS). Negligible variations in thermal conductivity, thermal diffusivity, and specific heat were observed by increasing the amount of DS in the mixture. In particular, the thermal conductivity values ranged between 0.45 ± 0.03 W m−1 K−1 (DS-50) and 0.50 ± 0.03 W m−1 K−1 (DS-30). Conversely, the color shift value and spectral reflectance in the infrared field were found directly proportional to the concentration of DS. Using dredged sediments as building material demonstrated to be a solution to the problem of their disposal and the scarcity of raw materials, reducing the global warming score by up to 2.8%

Mice with reduced expression of the telomere-associated protein Ft1 develop p53-sensitive progeroid traits

Human AKTIP and mouse Ft1 are orthologous ubiquitin E2 variant proteins involved in telomere maintenance and DNA replication. AKTIP also interacts with A- and B-type lamins. These features suggest that Ft1 may be implicated in aging regulatory pathways. Here, we show that cells derived from hypomorph Ft1 mutant (Ft1kof/kof ) mice exhibit telomeric defects and that Ft1kof/kof animals develop progeroid traits, including impaired growth, skeletal and skin defects, abnormal heart tissue, and sterility. We also demonstrate a genetic interaction between Ft1 and p53. The analysis of mice carrying mutations in both Ft1 and p53 (Ft1kof/kof ; p53ko/ko and Ft1kof/kof ; p53+/ko ) showed that reduction in p53 rescues the progeroid traits of Ft1 mutants, suggesting that they are at least in part caused by a p53-dependent DNA damage response. Conversely, Ft1 reduction alters lymphomagenesis in p53 mutant mice. These results identify Ft1 as a new player in the aging process and open the way to the analysis of its interactions with other progeria genes using the mouse model

Tranexamic Acid in Pertrochanteric Femoral Fracture: Is it a Safe Drug or Not?

AbstractBackground:There is a high incidence of blood transfusion following hip fractures in elderly patients.Aim:The aim of this study is to evaluate the effectiveness and complications of use of tranexamic acid in proximal femur nailing surgery.Materials and methods:Our sample group consisted of 90 patients suffering from pertrochanteric fractures surgically treated with osteosynthesis with SupernailGT(LimaCorporate). The classification system AO/OTA was used to divide the fractures into 31A1 (n=45) and 31A2 (n=45). The patients were divided into two groups: 47 patients were administered 15 mg of tranexamic acid per kg (group A) and 43 patients were administered placebo (group B). Blood counts were monitored daily to evaluate the rate of anemia. As a safety criterion, we monitored the possible occurrence of vascular events, symptomatic or not, over the 8 weeks post-surgery. Markers predicting mortality and deep venous thrombosis (DVE) were also monitored (fibrinogen D-dimer).Results:Blood loss occurring post-surgery can be influenced by numerous factors that are not linked to the use or non-use of tranexamic acid. While closely monitoring hemoglobin levels daily, we observed that 42% of the patients in group A required blood transfusion as opposed to 60% in group B. The results of the markers predicting mortality (alpha1-acid glycoprotein; albumin LDL) and those of DVE were not statistically significant between the two groups in this study (p>0.05).Conclusion:Based on this study, the use of tranexamic acid was statistically significant in reducing post-surgery blood loss