Emiliano Casati

Last Name

Casati

First Name

Emiliano

ORCID

0000-0002-3559-6954

Organisational unit

09696 - Bardow, André / Bardow, André

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Publications 1 - 10 of 10

Introducing FIVER: An Open-Source Tool to Simulate Heat Transfer in Participating Media and Arbitrary Geometries
Wetaski, Charles; Sas Brunser, Sebastian; Casati, Emiliano (2024)
A Solar Receiver Delivering Steam at 1500 C and Above: Experimental Results
Casati, Emiliano; Tièche, André; Hartner, Anton; et al. (2022)
Introducing FIVER: An Open-Source Tool to Simulate Heat Transfer in Participating Media and Arbitrary Geometries
Wetaski, Charles; Sas Brunser, Sebastian; Casati, Emiliano (2025)
SolarPACES Conference Proceedings
Decarbonization of industrial processes operating at above 1000 °C is a major challenge. A promising answer lies in concentrating solar thermal technologies, but current receivers operate at about 600 °C only. New concepts are needed to achieve the target temperatures with good efficiencies, thus enabling commercial deployments. Further advances require that researchers have access to simulation tools treating heat transfer problems in radiatively participating media accurately, which is seldom the case today. Here we present a first effort to bridge this gap, introducing FIVER (FInite VolumE Ray tracer), an open-source Matlab tool for solving transient radiative-conductive heat transfer problems in participating media with spectral properties and complex geometries. FIVER tackles the challenging simulations needed to design the solar receivers of the future, and we hope it will become a valuable tool for researchers investigating concentrating solar thermal receivers and other technologies needed to decarbonize high temperature processes.
Direct absorption of concentrated solar radiation by glass above 1000 °C
Casati, Emiliano; Steinfeld, Aldo (2019)
AIP Conference Proceedings ~ SolarPACES 2018: International Conference on Concentrating Solar Power and Chemical Energy Systems
Solar thermal trapping at 1,000°C and above
Casati, Emiliano; Allgoewer, Leo; Steinfeld, Aldo (2024)
Device
Common semi-transparent materials like quartz and water feature spectral optical properties characterized by low attenuation of visible radiation and strong absorption of infrared (IR) radiation emitted by hot surfaces. This leads to the thermal trap effect, exploitable in solar-concentrating applications to attain higher absorber temperatures and thermal efficiencies. Here, we demonstrate this effect at high temperatures with a quartz rod attached to an opaque absorber plate reaching 1,050°C when exposed to 135 suns of concentration, while the quartz front face remains at 450°C. A 3D heat transfer model, validated against the experimental data, is applied to determine the performance map of solar receivers exploiting thermal trapping. These are shown to achieve the target temperature with higher efficiency and/or needing a lower concentration than the reference unshielded absorber. Solar process heat at above 1,000°C can decarbonize key industrial applications such as cement manufacturing and metallurgical extraction.
A co-located solar receiver and thermal storage concept using silicate glass at 1000°C and above: Experiments and modeling in the optically-thick regime
Casati, Emiliano; Lankhorst, Adriaan; Desideri, Umberto; et al. (2019)
Solar Energy
This work presents the exploratory experimental results of a co-located solar receiver and thermal energy storage (TES) concept based on a pool of molten glass contained in a cavity, serving as solar receiver and TES medium simultaneously. Distinctive features of the system are the direct and volumetric absorption of solar radiation by the semi-transparent glass and a stationary TES medium. Only the charge cycle was studied, without a heat-removal system. Recycled soda-lime-silica (SLS) container glass of various colors was adopted as working medium in a setup tested at the ETH’s High Flux Solar Simulator (HFSS). A steady 3D heat transfer model of the experimental apparatus, which couples Monte-Carlo ray-tracing and CFD techniques, was developed and validated against the experimental results. The tests used the HFSS as the only energy source, with maximum radiative fluxes of 1.2  MW m-2 and power input of 1.5 kW directly absorbed by the glass, which reached measured temperatures of 1300 C , while the maximum temperatures –as predicted by the model– exceeded 1500 C. Such conditions were maintained for 5 to 10 h and no technical problems were encountered with the containment of the hot glass melt. These preliminary results demonstrate that silicate glasses are effective volumetric absorbers of solar radiation up to temperatures exceeding 1300 .
Mach Number Estimation and Pressure Profile Measurements of Expanding Dense Organic Vapors
Head, Adam J.; Michelis, Theodoros; Beltrame, Fabio; et al. (2023)
ERCOFTAC Series ~ Proceedings of the 4th International Seminar on Non-Ideal Compressible Fluid Dynamics for Propulsion and Power
This paper describes an experiment conducted within the nozzle test section of the Organic Rankine Cycle Hybrid Integrated Device (ORCHID) aimed at providing accurate data for the validation of NICFD flow solvers [5]. A supersonic flow of the dense vapor siloxane MM established in the nozzle of the setup was characterized by means of the schlieren technique and by pressure taps along the nozzle profile. The nozzle inlet conditions corresponded to a stagnation temperature and pressure of T0=253 ∘C and P0=18.36 bara . At these inlet conditions, the compressibility factor of the fluid is Z0=0.58 . The nozzle backpressure was equal to Pb=2.2 bara . The experimental data-set includes: 1) the average mid-plane local Mach number, which was derived from the schlieren images by estimating the angle of the Mach waves originating from the roughness of the upper and lower nozzle surfaces, 2) the angle of a shock wave generated by a 5∘ wedge placed at the nozzle exit, also detectable in the schlieren images, and 3) the static pressure distribution along the flow expansion acquired with a Scanivalve DSA3218 pressure scanner device. The Mach number at the nozzle exit estimated based on the schlieren images is M=1.95±0.05 , very close to the expected value of M=2 according to the design conditions of the experiment. The static pressure measurements have a maximum absolute uncertainty amounting to ±1.80 kPa in the initial stages of the expansion. This information was used to assess the capability of the open-source SU2 flow solver in evaluating the NICFD effects in a supersonic flow of MM when the fluid thermodynamic properties are modeled with a cubic equation of state. For this purpose, two-dimensional Euler simulations were carried out with SU2 for the operating conditions achieved in the experiment. The numerical results are in good agreement with the experimental data. The largest deviation between the simulation and experiment is observed in the nozzle uniform region, where two dips in the Mach number occur due to a slight local decrease in flow velocity owing to two weak shock waves. The shock wave generated by the wedge located at the nozzle outlet propagates with two different angles, namely, βabove=37.6∘±0.86 , and βbelow=31.6∘±0.64 , due to the axial misalignment of the wedge with respect to the flow.
Solar-powered organic Rankine cycles: A technical and historical review
Dickes, Rémi; Casati, Emiliano; Desideri, Adriano; et al. (2025)
Renewable and Sustainable Energy Reviews
This research work reports the historical and technical developments of solar-powered organic Rankine cycles from 1880 to the early 2020s. In total, more than two hundred units are identified and presented along three different periods, namely the Pioneering Era (1880–1960), the Golden Age (1960–2000) and the Renaissance (2000–2020s). Besides describing the historical context of these investigations, technical details of the power units, solar fields, thermal storage and other auxiliaries are documented in details. Out of the database gathered from the review, an extensive analysis is performed to highlight how system architectures, component technologies, applications and market competitiveness evolved over time. Ultimately, this research work intends to provide the reader a complete understanding of past successes and failures, in order to best guide future developments of solar-powered organic Rankine cycles.
Automated Measurement, Modeling, and Interpretation of Diffusion Coefficients in Multicomponent Liquids
Flake, Carsten; Kasterke, Marvin; Casati, Emiliano; et al. (2024)
Accurate modeling of transport properties is crucial for effectively operating and designing chemical processes. Unfortunately, existing models for liquid systems are predominantly approximate and empirical in nature, primarily due to a lack of experimental data for validation and development. This study introduces an automated approach to measure diffusion coefficients in liquid multicomponent mixtures using microfluidics and Raman micro-spectroscopy. The automation process replaces manual sample preparation, significantly reducing both time and error associated with the experimental setup and allowing for continuous measurements without interruption. One hour and one milliliter of sample volume suffice to perform a single diffusion experiment. Conducting multicomponent diffusion experiments close to a miscibility gap may result in negative main diffusion coefficients, a phenomenon that has been questioned in recent literature. We use different methods, including predictive models for diffusion coefficients, to assess the measurement results. Our findings show that negative main diffusion coefficients are possible but rare and indicate a strong non-ideal behavior.
Transkritisch und effizient: Kältemittelgemische für industrielle Wärmepumpen
Liebl, Lana; Widmaier, Philip Karl; Brendel, Leon P.M.; et al. (2025)

Publications 1 - 10 of 10

Emiliano Casati

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