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Deep comprehension of wind farm performance is a complicated task due to the multivariate dependence of wind turbine power on environmental variables and working parameters and to the intrinsic limitations in the quality of SCADA-collected measurements. Given this, the objective of this study is to propose an integrated approach based on SCADA data and Computational Fluid Dynamics simulations, which is aimed at wind farm performance analysis. The selected test case is a wind farm situated in southern Italy, where two wind turbines had an apparent underperformance. The concept of a space–time comparison at the wind farm level is leveraged by analyzing the operation curves of the wind turbines and by comparing the simulated average wind field against the measured one, where each wind turbine is treated like a virtual meteorological mast. The employed formulation for the CFD simulations is Reynolds-Average Navier–Stokes (RANS). In this work, it is shown that, based on the above approach, it has been possible to identify an anemometer bias at a wind turbine, which has subsequently been fixed. The results of this work affirm that a deep comprehension of wind farm performance requires a non-trivial space–time comparison, of which CFD simulations can be a fundamental part. [ABSTRACT FROM AUTHOR]

Assessing the wind resource in complex terrains with the level of accuracy required by industry is not a trivial task. The present study critically analyzes the different elements involved in the process and how they affect the predicted Annual Energy Production (AEP) of a wind farm. Five different sites in Italy, for which the installing company had a posteriori AEP data available, are considered. All sites are modeled with the windPRO software. To separate the effects related to the quality of experimental measurements from those due to the selected wind modeling techniques, two different approaches were followed. In the " horizontal" one, the minimum amount of wind data common to all installation sites were used, i.e., the measurements of one mast at one selected altitude for a single full year, thus highlighting the role of the terrain modelling. In the " vertical" approach, the analysis focused on the site with the most complex terrain, using wind data of different quality and duration, as well as different processing techniques, from the ubiquitous WAsP to WAsP-CFD. The results of the study confirm that, even in presence of high-quality measurements and a standard workflow, the accuracy of the farm's AEP estimation is strongly site-dependent. For mildly-complex terrains, the lack of accuracy in mast data can be compensated with a more advanced spatial scaling method, and vice versa. On the other hand, in presence of steep slopes or sneaky ridges, attention must be paid to both the experimental and modelling components. A scaling approach based on Computational Fluid Dynamics (CFD) is mandatory. In all cases, thermal effects such as atmospheric stability must be carefully evaluated and included in the assessment process. • Uncertainty quantification of wind turbines' AEP estimation in complex terrains. • Five mountain sites in Italy compared critically. • Effect of the terrain complexity shown by comparing the sites with the same modeling and data set quality. • Effect of data quality and modeling techniques shown by analyzing the same site with different approaches. • Higher-fidelity extrapolation methods are needed for complex terrains. [ABSTRACT FROM AUTHOR]

In order to satisfy the requirements of Directive 2010/31/EU for Zero Energy Buildings (ZEB), innovative solutions were investigated for building HVAC systems. Horizontal air-ground heat exchangers (HAGHE) offer a significant contribution in reducing energy consumption for ventilation, using the thermal energy stored underground, in order to pre-heat or pre-cool the ventilation air, in winter and summer, respectively. This is particularly interesting in applications for industrial, commercial and education buildings where keeping the indoor air quality under control is extremely important. Experimental measurements show that, throughout the year, the outside air temperature fluctuations are mitigated at sufficient ground depth (about 3 m) because of the high thermal inertia of the soil, the ground temperature is relatively constant and instead higher than that of the outside air in winter and lower in summer. The study aims to numerically investigate the behavior of HAGHE by varying the air flow rate and soil conductivity in unsteady conditions by using annual weather data of South-East Italy. The analysis shows that, in warm climates, the HAGHE brings a real advantage for only a few hours daily in winter, while it shows significant benefits in the summer for the cooling of ventilation air up to several temperature degrees, already by a short pipe. [ABSTRACT FROM AUTHOR]

The urban heat island (UHI) phenomenon may produce several cascade effects on citizens' health, energy consumption and air quality. Numerical modelling is recognised to be a powerful tool for the analysis of the UHI, although the question of which model to use (as implied in the 'fit-for-purpose' approach) much depends on the application and on the result of satisfactory validation against field measurements. In this paper, two different modelling approaches are applied, namely the integral-semi-Gaussian model ADMS-TH and the CFD-based model ENVI-met, to assess the UHI phenomenon in a city of south Italy (Lecce). Modelling results are validated against field measurements collected during summer 2012. The results suggest that the integral model has the ability of capturing the UHI cycle at city scale, while CFD modelling did not provide any substantial improvements in terms of local geometric effects on temperature distribution. [ABSTRACT FROM AUTHOR]

Abstract: This paper extends a former analysis on the thermal behavior of a new kind of scraped surface heat exchanger operated in laminar regime to treat hazelnut paste, a high viscous non-Newtonian fluid largely adopted in the Italian confectionary industry. This unit, named A-SSHE, presents an alternate arrangement of the scraping blades that allows doubling the exchanger thermal efficiency respect to conventional SSHE with continuous blades, mainly thanks to backmixing phenomena. Three-dimensional CFD simulations of the A-SSHE are used to estimate the overall heat transfer coefficient as a function of the main process parameters: blades rotational speed, flow rate and wall temperature. The heat transfer coefficient results slightly higher during cooling than during heating and increases much more with blades rotational speed than with mass flow rate. Dimensional analysis provides a correlation among heat transfer coefficient, fluid properties and easily measurable flow parameters. This correlation is useful to design and operate an A-SSHE treating high viscous food pastes. [Copyright &y& Elsevier]

Abstract: Over the last years, there was an increasing interest in keeping suitable microclimatic conditions for the preservation of artefacts: the artefacts preservation requirements may diverge from those of the museums visitors, willing to enjoy the works of art in a situation of psycho-physical wellness. The HVAC designers and engineers will have then to cooperate closely with the curator, in order to define a compromise between conflicting environmental performance requirements. In particular at the stage of air-conditioning system design or retrofit, it is extremely important to carry out a series of preliminary analysis to evaluate and monitor the existing environmental conditions and to anticipatory simulate and predict the post-intervention conditions. To this aim, advanced fluid-dynamic investigation tools (Computational Fluid Dynamic [CFD] techniques) enable to deal with the specificity of such topics and provide a useful decision-making support. [Copyright &y& Elsevier]

Rainfall thresholds represent the main tool for the Italian Civil Protection System for early warning of the threat of landslides. However, it is well-known that soil moisture conditions at the onset of a storm event also play a critical role in triggering slope failures, especially in the case of shallow landslides. This study attempts to define soil moisture (estimated by using a soil water balance model) and rainfall thresholds that can be employed for hydrogeological risk prevention by the Civil Protection Decentrate Functional Centre (CFD) located in the Umbria Region (central Italy). Two different analyses were carried out by determining rainfall and soil moisture conditions prior to widespread landslide events that occurred in the Umbria Region and that are reported in the AVI (Italian Vulnerable Areas) inventory for the period 1991-2001. Specifically, a 'local' analysis that considered the major landslide events of the AVI inventory and an 'areal' analysis subdividing the Umbria Region in ten sub-areas were carried out. Comparison with rainfall thresholds used by the Umbria Region CFD was also carried out to evaluate the reliability of the current procedures employed for landslide warning. The main result of the analysis is the quantification of the decreasing linear trend between the maximum cumulated rainfall values over 24, 36 and 48 h and the soil moisture conditions prior to landslide events. This trend provides a guideline to dynamically adjust the operational rainfall thresholds used for warning. Moreover, the areal analysis, which was aimed to test the operational use of the combined soil moisture-rainfall thresholds showed, particularly for low values of rainfall, the key role of soil moisture conditions for the triggering of landslides. On the basis of these results, the Umbria Region CFD is implementing a procedure aimed to the near real-time estimation of soil moisture conditions based on the soil water balance model developed ad hoc for the region. In fact, it was evident that a better assessment of the initial soil moisture conditions would support and improve the hydrogeological risk assessment. [ABSTRACT FROM AUTHOR]

Abstract: There is an increasing concern related to the releases of industrial hazardous materials (either toxic or flammable) due to terrorist attacks or accidental events in congested industrial or urban areas. In particular, a reliable estimation of the hazardous cloud footprint as a function of time is required to assist emergency response decision and planning as a primary element of any Decision Support System. Among the various hazardous materials, the hazard due to the road and rail transportation of liquefied petroleum gas (LPG) is well known since large quantities of LPG are commercialized and the rail or road transportation patterns are often close to downtown areas. Since it is well known that the widely-used dispersion models do not account for the effects of any obstacle like buildings, tanks, railcars, or trees, in this paper a CFD model has been applied to simulate the reported consequences of a recent major accident involving an LPG railcar rupture in a congested urban area (Viareggio town, in Italy), showing both the large influence of the obstacles on LPG dispersion as well as the potentials of CFD models to foresee such an influence. [Copyright &y& Elsevier]

This paper describes the application of a three-dimensional Computational Fluid Dynamic (CFD) model to simulate the Marmore waterfall (Italy), which is part of the complex hydraulic system Nera Velino rivers, Piediluco lake. The domain reconstruction has been performed through a non-conventional photogrammetry topographic surveying. The simulations have been performed employing a CFD model that solves the Navier?Stokes equations with the Large Eddy Simulations turbulence closure scheme and the Volume of Fluid multiphase method to handle the free-surface flow. A good agreement is achieved between the CFD model and the real waterfall flow. [ABSTRACT FROM AUTHOR]

Abstract: At the DIMNP (Department of Mechanical, Nuclear and Production Engineering) laboratories of University of Pisa (Italy) a pilot plant called HPBT (Hydrogen Pipe Break Test) was built in cooperation with the Italian Fire Brigade Department. The apparatus consists of a 12 m3 tank connected with a 50 m long pipe. At the far end of the pipeline a couple of flanges have been used to house a disc with a hole of the defined diameter. The plant has been used to carry out experiments of hydrogen release. During the experimental activity, data have been acquired about the gas concentration and the length of release as function of internal pressure and release hole diameter. The information obtained by the experimental activity will be the basis for the development of a new specific normative framework arranged to prevent fire and applied to hydrogen. This study is focused on hydrogen concentration as function of wind velocity and direction. Experimental data have been compared with theoretical and computer models (such as CFD simulations). [Copyright &y& Elsevier]

Abstract: Objective: The mechanisms by which smoking and hypertension lead to increased incidence of intracranial aneurysm (IA) formation remain poorly understood. The current study investigates the effects of these risk factors on wall shear stress (WSS) and oscillatory shear index (OSI) at the site of IA initiation. Methods: Two (n =2) IAs from two patients with history of smoking and hypertension were artificially removed with the help of software @neuFuse (Supercomputing Solutions®, Bologna, Italy) and the vessel geometry reconstructed to mimic the condition prior to IA formation. Two computational fluid dynamics (CFD) analyses were performed on each data-set by using in turn the normal physiological values of blood viscosity (BV), and high BV values specific to smoking and hypertension, obtained from literature. Results: At normal BV, high WSS (>15Pa) was observed at the site of IA initiation in both patients. When BV values specific to smoking and hypertension were used, both the areas affected by high WSS (>15Pa) and the maximum WSS were increased whilst the magnitude and distribution of OSI showed no significant change. Conclusions: Long-term exposure to high WSS may result in an increased risk of IA development. An incremental increase in areas of high WSS observed secondary to smoking and hypertension may indicate a further increase in the risk of IA initiation. Interestingly, the relationship between BV and the area of increased WSS was not linear, reflecting the need for patient-specific CFD analysis. [Copyright &y& Elsevier]

Abstract: The CVE (Chambre View Explosion) is an experimental facility owned by the DIMNP at the University of Pisa “Scalbatraio” laboratory to study the confined vented explosion phenomena in real environments. The CVE is a cubic apparatus of 25m3, equipped with two glass walls that enable to video record the explosion and the flame expansion, and the relevant path. The experimental campaign and the results here presented were focused on the investigation of the turbulence induced by obstacles on the vented deflagration for homogeneous conditions of concentration. For this purpose two sets of obstacles constituted by plates were designed and put inside the apparatus. Besides the experimental activities, also a modelling work has been carried out with the CFD code FLACS V8.1 (FLame ACceleration Simulator) in order to predict and reproduce the turbulent confined hydrogen vented explosion. A comparison between the experimental video recorded data and the same data reproduced through the CFD simulations is presented. [Copyright &y& Elsevier]

Abstract: In this study, numerical modelling of the flow and concentration fields has been undertaken for a deep street canyon in Naples (Italy), having aspect ratio (i.e. ratio of the building height H to the street width W) H/W =5.7. Two different modelling techniques have been employed: computational fluid dynamics (CFD) and operational dispersion modelling. The CFD simulations have been carried out by using the RNG k–ɛ turbulence model included in the commercial suite FLUENT, while operational modelling has been conducted by means of the WinOSPM model. Concentration fields obtained from model simulations have been compared with experimental data of CO concentrations measured at two vertical locations within the canyon. The CFD results are in good agreement with the experimental data, while poor agreement is observed for the WinOSPM results. This is because WinOSPM was originally developed and tested for street canyons with aspect ratio H/W ≌ 1. Large discrepancies in wind profiles simulated within the canyon are observed between CFD and OSPM models. Therefore, a modification of the wind profile within the canyon is introduced in WinOSPM for extending its applicability to deeper canyons, leading to an improved agreement between modelled and experimental data. Further development of the operational dispersion model is required in order to reproduce the distinct air circulation patterns within deep street canyons. [Copyright &y& Elsevier]

Accurate modeling of wastewater ultraviolet disinfection is fundamental as support for process optimization and control. Detailed modeling of hydrodynamics and fluence rate via computational fluid dynamics, coupled to laboratory studies of inactivation kinetics, are usually the preferred approach for UV disinfection modeling. Despite this approach often provides accurate predictive performance, it requires significantly high computational time, making it unfeasible for real-time process control. In this study, to enable an effective process control, black-box regression models were assessed as a modeling alternative for UV disinfection, synthesizing hydrodynamics, fluence rate and inactivation kinetics. UV disinfection of a full-scale wastewater treatment plant in Italy was monitored for 10 months, measuring influent and effluent E. coli concentration, turbidity, absorbance at 254 nm, temperature and flow rate at different UV doses. Considering the usually observed distribution of effluent E. coli concentration and the zero inflation of the collected dataset, Poisson, zero-inflated Poisson and Hurdle generalized linear models were tested, as well as two-part models coupling a classifier describing the E. coli zero-count events and a regressor estimating the magnitude of E. coli concentrations in positive-count events. The two-part artificial neural network model showed the best predictive performance, being able of both describing nonlinearities and handling the high proportion of null values in the dataset. The deployment of this model to control ultraviolet disinfection was simulated, estimating a plausible 63% energy saving. [Display omitted] • A neural network model for UV wastewater disinfection modeling was developed. • The model was successfully tested on a full-scale UV disinfection unit. • An effective method to handle zero inflation of E. coli counts data were developed. • The benefits of the UV model as a process control tool were highlighted. [ABSTRACT FROM AUTHOR]

• University buildings must be safe, secure and suitable for an "in-presence" education. • Architectural and technological retrofits are necessary to face the COVID-19. • HVAC-related measures anti-contagion need studies in both time and space domains. • A numerical model of a University building, calibrated against measurements, is proposed. • The design of refurbishment is performed by coupled numerical methods, BES and CFD. The proposed investigation is aimed at providing useful suggestions and guidelines for the renovation of educational buildings, in order to do University classrooms safe and sustainable indoor places, with respect to the 2020 SARS-CoV-2 global pandemic. Classrooms and common spaces have to be thought again, for a new "in-presence" life, after the recent worldwide emergency following the spring 2020 pandemic diffusion of COVID-19. In this paper, starting from a real case study, and thus the architectural and technological refurbishment of an Italian University building (Campobasso, South Italy, cold climate), with the aims of improving the classrooms' quality and safety, a comprehensive approach for the retrofit design is proposed. By taking into account the necessary come back to classrooms starting, hopefully, from the next months (Autumn 2020), experimental studies (monitoring and investigations of the current energy performances) are followed by the coupling of different numerical methods of investigations, and thus building performance simulations, under transient conditions of heat transfer, and computational fluid dynamics studies, to evidence criticalities and potentialities to designers involved in the re-thinking of indoor spaces hosting multiple persons, with quite high occupancy patterns. Both energy impacts, in terms of monthly and annual increase of energy demands due to higher mechanical ventilation, and indoor distribution of microclimatic parameters (i.e., temperature, airspeed, age of air) are here investigated, by proposing new scenarios and evidencing the usefulness of HVAC systems, equipment (e.g., sensible heat recovery, without flows' contamination) and suitability of some strategies for the air distribution systems (ceiling squared and linear slot diffusers) compared to traditional ones. [ABSTRACT FROM AUTHOR]

This paper presents the investigation of propeller-rudder-hull interaction by using Computational Fluid Dynamics (CFD), and Experimental Fluid Dynamics (EFD) approaches including the propeller's performance in cavitating conditions, particularly the effect of the tip vortex cavitation on the interaction phenomenon. The investigation was focused on the recently generated benchmark test data for the research catamaran, The Princess Royal, and its scaled model which was tested for cavitation and noise investigations in the large circulating water channel of CNR-INM, Italy within the scope of the European collaborative project. The propeller-rudder-hull interaction of a 1/3.4 scaled model of this vessel was simulated by using the commercial CFD software, STAR-CCM+, which implemented the Schnerr–Sauer cavitation model for the cavitation effect. Large Eddy Simulations (LES) was used for a better resolution of high velocity and pressure gradients to model the tip vortex cavitation. A new adaptive meshing technique using a Mesh Adoption Refinement Approach for Cavitation Simulations (MARCS) was applied for more effective modelling of the tip vortex cavitation during the propeller-rudder-hull interaction. The results of the CFD simulations were compared with the EFD data, particularly for the cavitation dynamics. • Experimental and numerical investigations of propeller cavitation including tip vortex cavitation (TVC). • CFD calculations for a propeller-rudder-hull arrangement in cavitating conditions. • Propeller-rudder-hull simulations including particularly TVC. • Development of an adaptive mesh refinement approach for simulating TVC in terms of propeller-rudder-hull interaction. • Comparisons between EFD and CFD results of the propeller cavitation investigations including TVC. [ABSTRACT FROM AUTHOR]

The complex interaction between the Urban Heat Island (UHI), local circulation, and air quality requires new methods of analysis. To this end, this study investigates the multiple scale nature of the UHI and its relationship with flow and pollutant dispersion in urban street canyons with and without the presence of vegetation. Two field experimental campaigns, one in summer and one in winter, were carefully designed in two parallel urban street canyons in the city of Bologna (44°29′ N, 11°20′ E; Italy) characterized by a similar orientation with respect to the impinging background flow but with a different aspect ratio and a different presence of vegetation. In addition to standard meteorological variables, the dataset collected included high-resolution flow data at three levels and concentration data of several pollutants. The UHI has been evaluated by combining surface temperature of building facades and ground surfaces acquired during two intensive thermographic campaigns with air temperature from several stations in order to verify the presence of intra-city neighborhood scale UHIs additional to the more classical urban–rural temperature differences. The presence of trees together with the different morphologies was shown to mitigate the UHI intensity of around 40% by comparing its value in the center of the city free of vegetation and the residential area. To capture the multiple-scale nature of UHI development, a simple relationship for the UHI convergence velocity, used as a surrogate for UHI strength, is proposed and used to establish the relationship with pollutant concentrations. The reliability of the proposed relationship has been verified using a Computational Fluid Dynamics (CFD) approach. The existence of a robust relationship between UHI strength and pollutant concentration may indicate that the positive effect of mitigation solutions in improving urban thermal comfort likely will also positively impact on air pollution. These results may be useful for a quick assessment of the pollutant accumulation potential in urban street canyons. [ABSTRACT FROM AUTHOR]

This paper is devoted to the assessment of urban greening effects on two important ecosystem services, i.e., air quality and CO2 storage, including the corresponding economic impacts in a real urban area, i.e., a district located in the Mediterranean city of Lecce (southern Italy). Two tools were employed, i-Tree Canopy and the computational fluid dynamics (CFD) microclimate model ENVI-met. i-Tree Canopy allowed fully determining the land-cover percentage on the basis of different ground cover classes and obtaining an estimate of annual values of CO2 storage, air pollutant removal, and economic benefits in the presence of urban greening. The estimate in i-Tree Canopy considered only the amount of greening; therefore, air pollutant removal estimates were only potential. As the vegetation was located in street canyons, its interaction with local meteorology and urban geometry strictly affected the dispersion of nitrogen oxides (NOx) (taken here as an example) as obtained from ENVI-met simulations. In ENVI-met, both deposition/absorption and aerodynamic effects were considered, and local increases in concentration were found in the district. The analysis of results obtained from different tools (one complex (CFD model) and the other simple (i-Tree model)) showed the error associated with the simple model in the computation of impacts if the interaction among the vegetation characteristics, the meteorological conditions, and the urban geometry was neglected; however, it also uncovers a novel approach for comprehensively characterizing a given area in terms of its vegetation cover, CO2 storage, and economic benefits, as well as local effects on air quality. This study is set in a broader context aimed at assessing the air quality in urban canopies of Mediterranean areas characterized by the presence of narrow street canyons where pollutants can accumulate due to ineffective air exchange with the above atmosphere. [ABSTRACT FROM AUTHOR]

Present in both plutonic and volcanic rocks, enclaves are inclusions of magma into a compositionally distinct magmatic host. Classical relationships between their shapes and the dynamical conditions that prevailed during their formation have been drawn from fluid–fluid analogies and from solid rock mechanics. Magmas, however, are hydrogranular suspensions with a rheology distinct from these two-end-members. This work presents results from computational fluid dynamics with discrete element modeling (CFD-DEM) aimed at deforming crystal-rich enclaves in pure shear. The CFD-DEM approach explicitly resolves solid–solid interactions such as contact and friction while taking into account fluid coupling. The first series of deformation involved only pure fluids to validate the setup. The second series comprised seven runs aimed at reproducing magmatic conditions. Enclaves were made of a cylindrical suspension of particles embedded into a host with different characteristics. In both media, particles and fluids had densities, viscosities, elastic characteristics, and sizes tailored to the geological constraints of the Adamello batholith, Italy. Each run corresponds to a temperature along the two respective crystallization paths and span crystal contents from 10 to 62 vol%. Results show that, to first order, deformation does not depend on differences in melt viscosities, crystal contents, or bulk viscosity contrast. This is due to the formation of force chains parallel to the main compression direction, which transmits stress across the enclave. A simple, first-order relationship could be fitted to our data to relate shear and enclave deformation, which we applied to the case of the Adamello pluton. There is a second-order dependence of deformation on the onset of particles contacts and force chains, which are both related to particle concentration. The main control of these second-order effects is the host crystal content. Enclave particles pack early, quickly erasing differences in initial content and building force chains parallel to the compression axis that transmit stresses to the host. Whether the host is able to transmit those stresses across its own volume is controlled by host crystal content. • Deformation of crystal-rich enclaves in pure shear was carried out by numerical simulations. • Particle–particle force chains transmit stress across the enclave. • Enclave deformation does not depend on viscosity contrasts. • Enclave deformation depends very little on host crystal content. [ABSTRACT FROM AUTHOR]

• The overall thermal efficiency from a deep borehole heat exchanger (DBHE) in a very hot geothermal system for 30 years is presented. • A transient Computational Fluid Dynamics (CFD) model is developed based on the initial measurements realized in the IDDP-1 well in Krafla. • Deepening the internal well allows to get more energy with more lateral cooling effect. • Direct-use application seems more suitable than electric power production for a conventional DBHE design. The geothermal energy sector is facing numerous challenges related to heat recovery efficiency and economic feasibility. Research on superheated/supercritical geothermal systems is progressing in Europe, triggered by the Iceland Deep Drilling project (IDDP) and the DESCRAMBLE project in Italy. In Iceland, the IDDP-1 well, which reached a magma intrusion at a depth of 2100 m, raised new opportunities to untap the geothermal potential near magmatic intrusions. Given their highly corrosive nature, geothermal fluids weaken the wellbores integrity during conventional geothermal production. Closed-loop Deep Borehole Heat Exchangers (DBHE) that do not require fluid exchange between the subsurface and the wells represent a strategic alternative for recovering heat from these unconventional geothermal resources, while minimising the risk of in situ reservoir damage. The thermal influence and heat recovery associated with a hypothetical DBHE drilled into the IDDP geological settings are investigated via Computational Fluid Dynamics (CFD) techniques, simulating 30 years of production. Two wellbore designs are modelled, based on simplified geological properties from the IDDP-1 well description. The results show that, during the first year of production, the output temperature is function of the working fluid velocity before reaching pseudo-steady state conditions. The cooling perturbation near the bottom hole is shown to grow radially from 10 to 40 m between 1 and 10 years of production, and the calculated output power reaches up to 1.2 MWth for a single well. The heat transfer at the bottom well bore is enhanced by extending the inner well deeper into the ground. Subject to full economic analysis to be performed at field scale, the significantly lower technical risks of the closed-loop DBHE could outweigh the lower thermal output per well compared to theoretical expectations from open-loop Enhanced Geothermal Systems (EGS). [ABSTRACT FROM AUTHOR]

The aim of this paper is to describe a multidisciplinary approach including biological and particle monitoring, and microclimate analysis associated with the application of the Computational Fluid Dynamic (CFD). This approach was applied at the Palatina historical library in Parma. Monitoring was performed both in July and in December, in the absence of visitors and operators. Air microbial monitoring was performed with active and passive methods. Airborne particles with a diameter of ≥0.3, ≥0.5, ≥1 and ≥5 μm/m3, were counted by a laser particle counter. The surface contamination of shelves and manuscripts was assessed with nitrocellulose membranes. A spore trap sampler was used to identify both viable and non-viable fungal spores by optical microscope. Microbiological contaminants were analyzed through cultural and molecular biology techniques. Microclimatic parameters were also recorded. An infrared thermal camera provided information on the surface temperature of the different building materials, objects and components. Transient simulation models, for coupled heat and mass-moisture transfer, taking into account archivist and general public movements, combined with the related sensible and latent heat released into the environment, were carried out applying the CFD-FE (Finite Elements) method. Simulations of particle tracing were carried out. A wide variability in environmental microbial contamination, both for air and surfaces, was observed. Cladosporium spp., Alternaria spp., Aspergillus spp., and Penicillium spp. were the most frequently found microfungi. Bacteria such as Streptomyces spp., Bacillus spp., Sphingomonas spp., and Pseudoclavibacter as well as unculturable colonies were characterized by molecular investigation. CFD simulation results obtained were consistent with the experimental data on microclimatic conditions. The tracing and distribution of particles showed the different slice planes of diffusion mostly influenced by the convective airflow. This interdisciplinary research represents a contribution towards the definition of standardized methods for assessing the biological and microclimatic quality of indoor cultural heritage environments., (Copyright © 2015 Elsevier B.V. All rights reserved.)