Conference Agenda

TOM7 S02: Thermal radiation and energy management 2
Tuesday, 13/Sept/2022:
2:30pm - 4:00pm

Session Chair: Svend-Age Biehs, Oldenburg University, Germany
Location: B116

1st floor, 70 seats

2:30pm - 3:00pm
ID: 292 / TOM7 S02: 1
TOM 7 Thermal radiation and energy management

Casimir-Lifshitz force at the water-ice interface in the triple point: premelting of ice on a rock surface

Victoria Esteso


Herein we show a theoretical study about ice-premelting on a quartz rock surface based on calculations of the Casimir-Lifshitz force at that interface. In order to do that we consider a four-layer system composed of rock-ice-water-air. In contrast to previous investigations, which only considered variations of the thickness of either the water or the ice layer, here we analyse the equilibrium conditions of the system when both layers may vary their thickness. This enables multiple alternative equilibrium solutions stabilized in part by repulsive Casimir-Lifshitz interactions. Therefore, the final state of a system will depend on initial conditions and may explain variations in experimental measurements of ice-premelting.

3:00pm - 3:30pm
ID: 255 / TOM7 S02: 2
TOM 7 Thermal radiation and energy management

Enhancing the solar-to-thermal energy conversion in high vacuum flat plate solar collectors

Roberto Russo1, Davide De Maio1,2, Carmine D'Alessandro1,2, Daniela De Luca1,3, Antonio Caldarelli1,2, Eliana Gaudino1,2, Marilena Musto1,2, Emiliano Di Gennaro1,3

1Consiglio Nazionale delle Ricerche, Istituto di Scienze Applicate e Sistemi Intelligenti, 80131 Napoli, Italy; 2Deparment of Industrial Engineering, Università degli Studi di Napoli “Federico II”, 80125 Napoli, Italy; 3Department of Physics, Università degli Studi di Napoli “Federico II”, 80125 Napoli, Italy

In solar flat plate collectors, the high vacuum insulation suppresses the convective losses increasing the collector efficiency. The solar-to-thermal energy conversion efficiency in such solar thermal collectors is mainly defined by the optical and radiation losses of the selective solar absorber. We present the full process of design, optimization, fabrication, and characterization of multilayer coatings specifically thought for working in high vacuum flat solar thermal collectors at different operating temperatures, from 100 °C to 300 °C. We discuss the relative importance of absorptance and emittance in determining the collector thermal efficiency. The robustness of the performance of the coatings related to the unpreventable errors in layer thickness during the manufacturing stage is also considered through a genetic optimisation algorithm.

3:30pm - 3:45pm
ID: 283 / TOM7 S02: 3
TOM 7 Thermal radiation and energy management

Electrically tunable radiative cooling under ambient conditions

Debashree Banerjee1,2, Tomas Hallberg3, Sampath Gamage1,2, Shangzhi Chen1, Hans Kariis3, Magnus P. Jonsson1,2

1Department of Science and Technology (ITN), Linkoping University, Norrköping 610 74, Sweden; 2Wallenberg Wood Science Center (WWSC), Linköping University, SE-601 74 Norrköping, Sweden; 3Department of Electro Optical Systems, FOI, Linköping, Sweden

The prospect and use of passive radiative coolers for mitigating energy consumption have been and now even more so, attractive for sustainability and environmental conservation. Cellulose-based as well as other organic and inorganic materials have shown promising performance as passive coolers but most of these concepts lacked the capability to dynamically tune the extent of cooling.

In this work we demonstrate the electrical control of radiative cooling at ambient conditions enabled by tuning the thermal emissivity of a conducting polymer. We show that electrochemical redox switching provides clear temperature variations of the device when exposed to optical conditions resembling that of the cold night sky. Our results conclusively show that the observed variations in temperature are due to variations in radiative cooling. Thus, our study establishes a novel concept to dynamically tune a sustainable method to cool down objects via thermal radiation through the atmosphere and into cold space.

3:45pm - 4:00pm
ID: 146 / TOM7 S02: 4
TOM 7 Thermal radiation and energy management

Numerical simulations of the radiative properties of Al/air flames

Iñigo González de Arrieta1,2, Cédric Blanchard1, Fabien Halter3

1CNRS, CEMHTI UPR3079, Univ. Orléans, F-45071 Orléans, France; 2Physics Department, University of the Basque Country UPV/EHU, E-48940 Leioa, Spain; 3ICARE-CNRS, 1C Avenue de la Recherche Scientifique, Orléans, 45071, France

Aluminium microparticles have been proposed as a potential green energy vector, given their high energy density and the availability of clean recycling routes for the combustion products. Unfortunately, the phenomenology of micron-sized Al-air flames remains poorly understood. This contribution presents a new experimental setup and an optical model that can be used to study the fundamental properties of these flames, in order to design appropriate combustion systems. The radiative properties of the flame have been simulated by considering each burning Al particles as a core-shell particle, in which the cloud of condensed burning products is replaced with an effective medium. Emission from these alumina nanoparticles dominates the radiation profile and is required in order to better use pyrometric temperature measurements. This simplified model constitutes a starting point for more in-depth studies of heat transfer in Al/air flames.

4:00pm - 4:15pm
ID: 286 / TOM7 S02: 5
TOM 7 Thermal radiation and energy management

Mid-infrared narrowband polarization management with Al doped ZnO-ZnWO4 eutectic composites

Marco Centini1, Maria Cristina Larciprete1, Concita Sibilia1, Dorota A. Pawlak2

1Department of Basic and Applied Sciences for Engineering, SAPIENZA, University of Rome, Via A. Scarpa 16, 00161, Roma, Italy; 2ENSEMBLE3 sp. z o.o., Wolczynska 133, 01-919 Warsaw, Poland

We report a narrowband polarization-dependent reflectivity from Al-doped ZnO/ZnWO4 self-assembled eutectic composites in the mid-infrared range. Our results show a reflectivity modulation from 0.05 to 0.75 for two orthogonal polarizations of the incident field with a 10% Al concentration. Acting as natural polarizing filters these eutectic composites could open the way to the future development of low-cost photonics components in the IR.