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Pathway to Zero-Emission Buildings: Energy and Economic Comparison of Different Demand Coverage by RES for a New Office Building
Get PDFIn recent years, energy efficiency and the decarbonization of the building sector have become key goals in Europe. However, substantial efforts are still needed to support the increase in on-site energy generation from renewable energy sources (RES) and to phase-out the use of fossil fuels. Moreover, this challenge must be backed by financial mechanisms provided by Member States. In this context, the aim of this work is to investigate different RES generation layouts for a reference office building in Italy and to determine whether it can achieve the goal of a net zero energy building (net ZEB) or a positive energy building (PEB). Different layouts are analyzed from both energy and economic perspectives through dynamic energy simulation, considering different financial schemes, such as “net metering” (SSP) and “premium tariff” (RID). The results show that the energy performance improves due to the size and the characteristics of the PV system. However, the avoided operating costs due to RID increase linearly, while the economic benefits provided by the SSP scheme encourage an appropriate design of the renewable energy system, avoiding oversizing for economic profitability
Geometrical and PCM optimization of a thermocline energy storage system
No full textThis work presents an optimized thermal energy storage (TES) system based on thermocline technology. A prototype of a single-medium (molten salt) thermocline storage system was built and tested at the ENEA Casaccia Research Center, which consists of a single tank equipped with an internal vertical channel to drive the salt motion by natural convection. At the channel ends, two serpentines are installed for charging (bottom serpentine) and for discharging (top serpentine). In this study, the thermocline prototype was numerically optimized by modifying its geometry and introducing a phase change material (PCM) in the design. First, the tank geometry was modified to involve the entire tank in the thermal stratification and to avoid undesirable heat transfer during the charge/discharge processes. Then, sets of PCM toroidal tubes were inserted at different heights inside the modified tank, increasing the thermal storage capacity of the system by a maximum of about 23 %. In addition, PCM inserts are expected to stabilize the salt temperature close to the serpentines. A transient 2D CFD model was developed to determine heat losses and the salt temperature distribution in the tank. This model was coupled with a lumped-parameter model aimed at computing the PCM temperature and the corresponding heat transfer coefficient. The storage tank geometrical optimization resulted in an increase of 9.6 % and 22.7 % in the stored and recovered energy, respectively. This optimization also indicated enhancement in the TES system in terms of charging/discharging efficiency and heat storage/release ratio. The PCM integration demonstrated a further improvement in the thermal performance of the TES system due to the PCM latent heat. For the charging process, configurations with PCM inserts achieved the highest charging efficiency and heat storage ratio, corresponding to an increase of ~18 % in the stored energy by inserting PCM tubes at both top/bottom locations. For the discharging process, the PCM integration did not lead to a considerable change in discharging efficiency and heat release ratio. However, including the PCM inserts at both top/bottom locations increased the recovered energy by ~14 % compared to the case without PCM
Robots for the Energy Transition: A Review
Get PDFThe energy transition relies on an increasingly massive and pervasive use of renewable energy sources, mainly photovoltaic and wind, characterized by an intrinsic degree of production uncertainty, mostly due to meteorological conditions variability that, even if accurately estimated, can hardly be kept under control. Because of this limit, continuously monitoring the operative status of each renewable energy-based power plant becomes relevant in order to timely face any other uncertainty source such as those related to the plant operation and maintenance (O&M), whose effect may become relevant in terms of the levelized cost of energy. In this frame, the use of robots, which incorporate fully automatic platforms capable of monitoring each plant and also allow effective and efficient process operation, can be considered a feasible solution. This paper carries out a review on the use of robots for the O&M of photovoltaic, wind, hydroelectric, and concentrated solar power, including robot applications for controlling power lines, whose role can in fact be considered a key complementary issue within the energy transition. It is shown that various robotic solutions have so far been proposed both by the academy and by industries and that implementing their use should be considered mandatory for the energy transition scenario
Vegetation Effects on Air Pollution: A Comprehensive Assessment for Two Italian Cities
Get PDFThe role of urban vegetation in urban air quality is usually assessed by considering only the pollutant removal capacity of the plants. This study aims to show, for the first time, the effects of vegetation on air pollutant concentrations through its effects on meteorology, separately from its biogenic emissions. It also investigates how air quality changes when only biogenic emissions are altered by using plants with different emission factors, as well as the potential effects of introducing new vegetation into urban areas. These assessments were conducted using atmospheric modelling systems currently employed for air quality forecasting and planning, configured specifically for the cities of Bologna and Milan. Simulations were performed for two representative months, July and January, to capture summer and winter conditions, respectively. The variability in air concentrations of ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM10) within the municipal boundaries was assessed monthly. When evaluating the impact of future vegetation, changes in temperature, wind speed, and relative humidity were also considered. The results indicate that vegetation influences air quality more significantly through changes in meteorological conditions than through biogenic emissions. Changes in biogenic emissions result in similar behaviours in O3 and PM10 concentrations, with the latter being affected by the changes in the concentrations of secondary biogenic aerosols formed in the atmosphere. Changes in NO2 concentrations are controlled by the changes in O3 concentrations, increasing where O3 concentrations decrease, and vice versa, as expected in highly polluted areas. Meteorologically induced vegetation effects also play a predominant role in depositions, accounting for most of the changes; however, the concentrations remain high despite increased deposition rates. Therefore, understanding only the removal characteristics of vegetation is insufficient to quantify its effects on urban air pollution
Charge amplification in low pressure CF4:SF6:He mixtures with a multi-mesh ThGEM for directional dark matter searches
Get PDFThe CYGNO collaboration is developing next generation directional Dark Matter (DM) detection experiments, using gaseous Time Projection Chambers (TPCs), as a robust method for identifying Weakly Interacting Massive Particles (WIMPs) below the Neutrino Fog. SF6 is potentially ideal for this since it provides a high fluorine content, enhancing sensitivity to spin-dependent interactions and, as a Negative Ion Drift (NID) gas, reduces charge diffusion leading to improved positional resolution. CF4, although not a NID gas, has also been identified as a favourable gas target as it provides a scintillation signal which can be used for a complimentary light/charge readout approach. These gases can operate at low pressures to elongate Nuclear Recoil (NR) tracks and facilitate directional measurements. In principle, He could be added to low pressure SF6/CF4 without significant detriment to the length of 16S, 12C, and 19F recoils. This would improve the target mass, sensitivity to lower WIMP masses, and offer the possibility of atmospheric operation; potentially reducing the cost of a containment vessel. In this article, we present gas gain and energy resolution measurements, taken with a Multi-Mesh Thick Gaseous Electron Multiplier (MMThGEM), in low pressure SF6 and CF4:SF6 mixtures following the addition of He. We find that the CF4:SF6:He mixtures tested were able to produce gas gains on the order of 104 up to a total pressure of 100 Torr. These results demonstrate an order of magnitude improvement [1] in charge amplification in NID gas mixtures with a He component
A statistical study of precipitation on the eastern antarctic plateau (Dome-C) using remote sensing and in-situ instrumentation
Get PDFStudying precipitation at very high latitudes is a challenge, particularly during the polar winter. Direct monitoring of ice habit and size in high latitude precipitation is crucial for validating the algorithms used to derive precipitation from radar, and for improving the climatological modeling of polar areas. The high plateau lacks long-term direct observations of precipitation. In this work, carried out at Concordia Station (Dome-C (DC), −75°S, 123°E, 3233 m a.m.s.l), the use of a depolarization LIDAR, a flatbed scanner (ICECAMERA), a microwave profiler (HAMSTRAD) and meteorological instrumentation made possible the study, over the period 2014–2021, of shape, size, height and temperature of formation of precipitation. The precipitation sources were classified into four types: ice fogs, liquid fogs, mixed-phase clouds, and cirrus. Ten representative ice habits for Dome-C were chosen. The size distribution for every habit was calculated, allowing for the estimation of the corresponding radar reflectivity. The use of W-band radars, such as CLOUDSAT, with a sensitivity of −28dB, resulted in capturing all the crystals observed in Concordia. A positive trend was observed between grain size and height in ice habits that are typical of cloud precipitation. North West (NW) and North East (NE) winds at cloud height, blowing from coastal regions, caused the majority of precipitation from clouds. The study also examined the height trend of the ice habit composition of precipitation. The ice habit composition for each of the four types of precipitation source was analyzed, and the possibility of determining the source by simply observing the precipitation was explored. This work marks the first comprehensive investigation of precipitation on the eastern Antarctic plateau
Characterisation of SiC Varistors at Ambient and Elevated Temperatures for Protection of Superconducting Magnets
No full textHigh-energy varistors comprised of a silicon carbide (SiC) composite material have been used as an alternative to linear dump resistors for quench protection/energy extraction for superconducting magnets. However, characterisation work is required for accurate simulations, in particular at elevated temperatures. For magnets with a high inductance or large stored energy, energy extraction can take several seconds, during which time the varistor temperature increase can affect the voltage characteristics throughout the discharge. This work presents the variations of the parameters of SiC varistors at ambient and elevated temperature and include their effects to model the energy extraction and discharge, using the scenario of the DTT toroidal field coil quench protection and energy extraction, which will use varistors
Advanced Electrospun Composites Based on Polycaprolactone Fibers Loaded with Micronized Tungsten Powders for Radiation Shielding
Get PDFExposure to high levels of radiation can cause acute, long-term health effects, such as acute radiation syndrome, cancer, and cardiovascular disease. This is an important occupational hazard in different fields, such as the aerospace and healthcare industry, as well as a crucial burden to overcome to boost space applications and exploration. Protective bulky equipment made of heavy metals is not suitable for many advanced purporses, such as mobile devices, wearable shields, and manned spacecrafts. In the latter case, the in-space manufacturing of protective shields is highly desirable and remains an unmet need. Composites made of polymers and high atomic number fillers are potential means for radiation protection due to their low weight, good flexibility, and good processability. In the present work, we developed electrospun composites based on polycaprolactone (polymer matrix) and tungsten powder for application as shielding materials. Electrospinning is a versatile technology that is easily scalable at an industrial level and allows obtaining very lightweight, flexible sheet materials for wearables. By controlling tungsten powder size, we engineered homogeneous, stable and processable suspensions to fabricate radiation composite shielding sheets. The shielding capability was assessed by an in vivo model on prototype composite sheets containing 80 w% of W filler in a polycaprolactone (PCL) fibrous matrix by means of irradiation tests (X-rays) on mice. The obtained results are promising; as expected, the shielding effectivity of the developed composite material increases with the thickness/number of stacked layers. It is worth noting that a thin barrier consisting of 24 layers of the innovative shielding material reduces the extent of apoptosis by 1.5 times compared to the non-shielded mice
Ultraviolet-C Light Effects in Actinidia spp. Infected by Pseudomonas syringae pv. actinidiae
Get PDFSeveral studies have demonstrated that ultraviolet-band-C (UV-C) irradiation can enhance plants’ natural resistance to pathogens and diseases. A suitable dose of UV-C radiation induces the production of metabolites that strengthen plant defenses, an effect known as “hormesis”. Hormesis presents a promising alternative that could supplement and reduce the use of pesticides, which pose risks to the environment and human health. This paper investigates the effects of UV-C radiation emitted by an array of Light-Emitting Diodes (LEDs) in generating a hormetic response in three kiwifruit species, namely A. chinensis var. deliciosa cv. Hayward, A. chinensis var. chinensis cv. Soreli®, and A. arguta plantlets, grown in vitro and in pots, exposed to the pathogen Pseudomonas syringae pv. actinidiae (Psa) either before or after UV-C irradiation. Analyses of morpho-physiological parameters and spectrophotometric assays were conducted to evaluate changes in chlorophyll a and b content, carotenoids, total phenols, and antioxidant activity in relation to the UV-C irradiation. Results indicate partial protection against Psa infection and increased levels of chlorophylls, carotenoids, polyphenols and antioxidant activity. The optimal UV-C dose was determined to be 2.2 kJ/m2 for in vitro shoots and 1.3 kJ/m2, for ex vitro plants
Flow cytometry: Unravelling the real antimicrobial and antibiofilm efficacy of natural bioactive compounds
No full textFlow cytometry (FCM) provides unique information on bacterial viability and physiology, allowing a real-time early warning antimicrobial and antibiofilm monitoring system for preventing the spread risk of foodborne disease. The present work used a combined culture-based and FCM approach to assess the in vitro efficacy of essential oils (EOs) from condiment plants commonly used in Mediterranean Europe (i.e., thyme EO, oregano EO, basil EO, and lemon EO) against planktonic and sessile cells of food-pathogenic Listeria monocytogenes 56 LY, and contaminant and alterative species Escherichia coli ATCC 25922 and Pseudomonas fluorescens ATCC 13525. Evaluation of the bacterial response to the increasing concentrations of natural compounds posed FCM as a crucial technique for the quantification of the live/dead, and viable but non-culturable (VBNC) cells when antimicrobial agents exert no real bactericidal action. Furthermore, the FCM results displayed higher numbers of viable bacteria expressed as Active Fluorescent Units (AFUs) with a greater level of repeatability compared with outcomes of the plate-count method. Overall, accurate counting of viable microbial cells is a critically important parameter in food microbiology, and flow cytometry provides an innovative approach with high-throughput potential for applications in the food industry as “flow microbiology”