Energy Conversion

We are a research group focused on energy conversion across different physical domains: thermal, electrical, and optical

Our work spans the design, optimization and experimental characterization of devices capable of transforming energy from one form to another.

We develop advanced thin-film coatings via sputtering tailored for specific thermo-optical functionalities.

Our activities include the engineering of solar thermal collectors, selective emitters, hybrid photovoltaic-thermal (PVT) devices for cogeneration, and solid-state thermoelectric heat pumps based on Peltier modules. Experimental setups operate under vacuum to suppress convective losses and recreate realistic operating environments.

Our “Mini Test Box” (MTB) enables accurate testing at controlled temperatures. Optical characterization covers both the visible and infrared ranges, leveraging tools such as spectrophotometers, integrating spheres, and FTIR systems.

Solar Thermal Conversion

We fabricate and study solar-selective absorbers designed to minimize thermal emission while maximizing solar absorption. These coatings, deposited via sputtering…

[expand text]

Cogeneration systems: PVT

The future of solar technology is hybrid. We study hybrid photovoltaic-thermal (PVT) devices which operate under high vacuum (HV PVT) and exploit the full solar…

[expand text]

Thermoelectric Modules

We characterize thermoelectric modules based on the Peltier effect, which enable solid-state heat pumping. Our approach focuses on evaluating…

[expand text]

Recent Publications and Conference Papers

TitleAuthorsYearConferenceSource title
Optical and structural properties of TaC thin films: Towards design of an efficient high temperature solar absorber coatingDe Luca D.; Caldarelli A.; Russo R.; Gawade T.C.; Bera P.; Barshilia H.C.2025-Solar Energy
Thermal emittance measurement of low-emissive materials for enhanced conversion efficiency in vacuum-based solar thermal applicationsGaudino E.; Farooq U.; Caldarelli A.; Strazzullo P.; De Luca D.; Di Gennaro E.; Russo R.; Musto M.2025-Solar Energy
Energy comparison analysis between direct and indirect dry saturated steam generation, thermally powered by EFPCs’ solar fieldsLevrano A.; Anacreonte A.V.; Gaudino E.; Vitobello R.; Sparano S.; Russo R.; Musto M.202440st UIT - Assisi, ItalyJournal of Physics: Conference Series
Optical Characterisation of Doped Silicon Wafers Using THz Time-Domain EllipsometryMazaheri Z.; Casalino M.; Iodice M.; Papari G.; Russo R.; Andreone A.2024EOSAM 2024 - Naples, ItalyEPJ Web of Conferences
Numerical performance investigation of High Vacuum Flat Plate Hybrid Photovoltaic-Thermal devicesStrazzullo P.; De Luca D.; Caldarelli A.; Gaudino E.; Musto M.; Di Gennaro E.; Russo R.202440st UIT - Assisi, ItalyJournal of Physics: Conference Series
Hemispherical Emittance in Multilayer Solar Absorbers: A MATLAB-Based Approach for Optimizing Solar Thermal EfficiencyGaudino E.; Caldarelli A.; De luca D.; Farooq U.; Strazzullo P.; Di Gennaro E.; Musto M.; Russo R.2024ICAE 2023 - Doha, QatarEnergy Proceedings
Infrared and conductive properties of TCO films deposited by magnetron sputtering at different temperaturesDi Napoli A.; Gaudino E.; Strazzullo P.; Farooq U.; Musto M.; De Luca D.; Krammer A.; Schueler A.; De Gennaro E.; Russo R.2024EOSAM 2024 - Naples, ItalyEPJ Web of Conferences
A Highly Efficient, Selective, and Thermally Stable Dielectric Multilayer Emitter for Solar ThermophotovoltaicsCaldarelli A.; De Luca D.; Lee C.; Sanitá G.; Esposito E.; Musto M.; Russo R.; Bermel P.2024-Solar RRL
Alpha and beta-voltaic silicon devices operated at cryogenic temperatures: An energy source for deep space explorationPalmieri V.G.; Casalino M.; Di Gennaro E.; Romeo E.; Russo R.2024-Next Energy
Detailed studies on sputter-deposited Hf and HfC thin films for solar energy devicesCaldarelli A.; De Luca D.; Lee C.; Sanitá G.; Esposito E.; Musto M.; Russo R.; Bermel P.2023-Solar Energy Materials and Solar Cells
Modeling of energy and exergy efficiencies in high vacuum flat plate photovoltaic–thermal (PV–T) collectorsDe Luca D.; Caldarelli A.; Gaudino E.; Di Gennaro E.; Musto M.; Russo R.2023-Energy Reports
High vacuum flat plate photovoltaic-thermal (HV PV-T) collectors: Efficiency analysisDe Luca D.; Strazzullo P.; Di Gennaro E.; Caldarelli A.; Gaudino E.; Musto M.; Russo R.2023-Applied Energy
Formulation of an Efficiency Model Valid for High Vacuum Flat Plate CollectorsGaudino E.; Caldarelli A.; Russo R.; Musto M.2023-Energies
Low emissivity thin film coating to enhance the thermal conversion efficiency of selective solar absorber in high vacuum flat plate collectorsCaldarelli A.; Gaudino E.; De Luca D.; Farooq U.; Musto M.; Di Gennaro E.; Russo R.2023-Thin Solid Films
Evaluation of the absorber temperature frequency function valid for evacuated flat plate collectorsGaudino E.; Musto M.; Caldarelli A.; De Luca D.; Di Gennaro E.; Russo R.2022-Energy Reports
Ultra-thin sputter-deposited infrared rugate mirror for enhancing solar-to-thermal energy conversionde Luca D.; Kortge D.; Gennaro E.D.; Russo R.; Bermel P.2022-Optics Letters
Solar selective coatings for evacuated flat plate collectors: Optimisation and efficiency robustness analysisDe Maio D.; D'Alessandro C.; Caldarelli A.; Musto M.; Russo R.2022-Solar Energy Materials and Solar Cells
Calorimetric testing of solar thermal absorbers for high vacuum flat panelsD'Alessandro C.; De Maio D.; Caldarelli A.; Musto M.; Di Giamberardino F.; Monti M.; Mundo T.; Di Gennaro E.; Russo R.; Palmieri V.G.2022-Solar Energy
Optimized Solar Absorber Coatings For Efficient Thermal Energy Conversion In Evacuated Flat Plate CollectorsCaldarelli A.; D’Alessandro C.; De Maio D.; De Luca D.; Gaudino E.; Musto M.; Gennaro E.D.; Russo R.2022OIC 2022 - Whistler, CanadaOptics InfoBase Conference Papers
Optimized solar absorber coating for a new concentrating solar collector under high vacuumDe Maio D.; D'Alessandro C.; Caldarelli A.; Musto M.; Russo R.2022SolarPACES 2020 - OnlineAIP Conference Proceedings
Performance of a CPC inserted in a high vacuum envelopeD'Alessandro C.; De Maio D.; De Luca D.; Musto M.; Di Gennaro E.; Russo R.2022SolarPACES 2020 - OnlineAIP Conference Proceedings
Rugate filters for evacuated thermal collectors: IR mirror for improvement of energy conversion efficiencyDe Luca D.; Kortge D.; Bermel P.; Di Gennaro E.; Russo R.2021NCSTRC IV 2021 - San Diego, California United StatesProceedings of SPIE - The International Society for Optical Engineering
Multilayers for efficient thermal energy conversion in high vacuum flat solar thermal panelsDe Maio D.; D'Alessandro C.; Caldarelli A.; De Luca D.; Gennaro E.D.; Casalino M.; Iodice M.; Gioffre M.; Russo R.; Musto M.2021-Thin Solid Films
Tuning silicon nitride refractive index through radio-frequency sputtering powerDe Luca D.; Di Gennaro E.; De Maio D.; D'Alessandro C.; Caldarelli A.; Musto M.; Koral C.; Andreone A.; Fittipaldi R.; Di Meo V.; Iodice M.; Russo R.2021-Thin Solid Films
Characterization and thermal aging tests of Cr based multilayer for unconcentrated solar thermal applicationsCaldarelli A.; D'Alessandro C.; De Maio D.; De Luca D.; Gaudino E.; Musto M.; Di Gennaro E.; Russo R.2021-Thin Solid Films
A selective solar absorber for unconcentrated solar thermal panelsDe Maio D.; D’alessandro C.; Caldarelli A.; De Luca D.; Di Gennaro E.; Russo R.; Musto M.2021-Energies
Performance analysis of evacuated solar thermal panels with an infrared mirrorD'Alessandro C.; De Maio D.; Musto M.; De Luca D.; Di Gennaro E.; Bermel P.; Russo R.2021-Applied Energy
Low cost high intensity LED illumination device for high uniformity solar testingD'Alessandro C.; De Maio D.; Mundo T.; Musto M.; Di Giamberardino F.; Monti M.; Dalena D.; Palmieri V.G.; De Luca D.; Di Gennaro E.; Russo R.2021-Solar Energy
Rugate filter window coating for improvement of vacuum solar thermal absorber efficienciesDe Luca D.; Russo R.; DI Gennaro E.; Bermel P.2020NCSTRC III 2020 - OnlineProceedings of SPIE - The International Society for Optical Engineering
Measurements of Spectrally Averaged Absorptivity and Emissivity for a Selective Solar Absorber in High Vacuum under Direct Solar IlluminationD'Alessandro C.; De Maio D.; De Luca D.; Musto M.; Di Gennaro E.; Rotondo G.; Dalena D.; Russo R.202040st UIT - Padova, ItalyJournal of Physics: Conference Series
Thermal Efficiency of a Concentrating Solar Collector under High-VacuumDe Maio D.; Alessandro C.D.; De Luca D.; Musto M.; Di Gennaro E.; Rotondo G.; Russo R.202040st UIT - Padova, ItalyJournal of Physics: Conference Series
Infrared mirror coating to improve efficiency in solar thermal energy applicationsDe Luca D.; D’Alessandro C.; De Maio D.; Di Gennaro E.; Musto M.; Rotondo G.; Russo R.2019IPRSN 2019 - Burlingame, California United StatesOptics InfoBase Conference Papers
Solar selective coating for thermal applicationsD’Alessandro C.; De Maio D.; De Luca D.; Gennaro E.D.; Gioffrè M.; Iodice M.; Musto M.; Rotondo G.; Dalena D.; Russo R.2019SMT33 2019 - Naples, ItalyKey Engineering Materials
Performances of a CPC collector inside a high vacuum flat panelRusso R.; Di Giamberardino F.; Monti M.; D'Alessandro C.; De Maio D.; Musto M.; Palmieri V.G.2018FTS 2018 - Singapore, SingaporeOptics InfoBase Conference Papers
The absorptance of selective solar absorber working in high vacuumRusso R.; Monti M.; D’Alessandro C.; De Maio D.; Musto M.; Koral C.; Andreone A.; Di Giamberardino F.; Palmieri V.G.2018INCPT 2018 - Lecce, ItalyIET Conference Publications
Characterization of selective solar absorber under high vacuumRusso R.; Monti M.; Giamberardino F.D.I.; Palmieri V.G.2018Optics Express
Measurement of selective solar absorbers emission and absorption coefficients under high vacuumMonti M.; Giamberardino F.D.; Palmieri V.G.; Russo R.2017OSE 2017 - Boulder, Colorado United StatesOptics InfoBase Conference Papers

Thermoelectric Modules


Thermoelectric coolers are reliable and compact solid-state heat pumps. Manufacturers provide the characteristic curves of the devices in their datasheets, but we faced an important question: which is the behaviour of thermoelectric coolers under high-vacuum conditions? The designed high-vacuum measuring system replaces the traditional insulators like polyurethane and polystirene with the vacuum insulation, reproducing real working conditions without convective losses.
EFESTO Group - Research material

The experimental setup is a vacuum chamber where the thermoelectric cooler under test is placed between an external sink to remove heat from the hot side, and a copper heater to control the cold side temperature.
The vacuum measuring station ensures three main advantages when compared to traditional ones:
1) Reduced thermal losses;
2) One-dimensional heat flux;
3) Suitable for arrays and multistages Peltier cells.
EFESTO Group - Research material

Thermal tests conducted on a commercial Peltier cell show that the behaviour of the thermoelectric coolers under high-vacuum conditions follows the characteristic curves provided by the manufacturer. Results show that the vacuum measuring station provides accurate measurements of the cooling power of a thermoelectric cooler. If you are interested in the methods, follow the link: https://dx.doi.org/10.2139/ssrn.5188848.
Beyond conventional uses, we are exploring innovative applications such as thermal management for biomedical devices and others, expanding the versatility of thermoelectric technologies. Stay tuned to discover our applications with thermoelectric coolers!

Cogeneration systems: PVT

The future of solar technology is hybrid. We study hybrid photovoltaic-thermal (PVT) devices which operate under high vacuum (HV PVT) and exploit the full solar spectrum, generating both electricity and heat while minimizing energy losses.

We develop low-emissivity transparent conductive oxides (TCOs) by sputtering to increase the operational temperature range. The MTB is used to measure both electrical output and thermal harvesting, validating performance under near-realistic conditions.

Solar Thermal Conversion

We fabricate and study solar-selective absorbers designed to minimize thermal emission while maximizing solar absorption. These coatings, deposited via sputtering, are tested in the MTB under high vacuum to mimic real solar collector conditions.

At 200 °C, our optimized surfaces reach up to 80% efficiency. We assess spectral absorptance and emittance both before and after thermal aging to ensure durability. Our expertise in thermo-optical engineering extends to other surface functionalities, including selective emitters.