ULTRA HIGH TEMPERATURE THERMOPHOTOVOLTAIC TECHNOLOGY COMBINED WITH THERMIONIC

ULTRA HIGH TEMPERATURE THERMOPHOTOVOLTAIC TECHNOLOGY COMBINED WITH THERMIONIC ENERGY CONVERSION A. Datas, E. Antolin, P. G. Linares, J. Villa, A. Marti Instituto de Energia Solar, Universidad Politecnica de Madrid D. M. Trucchi, A. Bellucci*, M. Girolami Dia. Thema Lab, Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche A. Vitulano, G. Sabbatella IONVAC Process Srl, Pomezia (Rm) alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

The energy demand Energy storage capacity / total world generation capacity = 2. 6 % 95% of total storage capacity is pumped hydroelectric 5% Thermal Energy Storage - TES (40%) TES represents the future way to satisfy the energy demand alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Thermal Energy Storage and Conversion Concentrated Solar Power (CSP) represents 75% of global TES Molten salt (290 -565 °C) Rankine Steam (540 °C , 100 -160 bar) Actual limitations: ü No possibility to exploit high temperatures ü Mechanical degradation alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Future direction: Increase the temperature Carnot efficiency 72% 64% Liquid Hydrogen 54% High temperature State of the art Pressurized Hydrogen (700 bar) Solar salts (5 -20 $/k. Wh) Li-ion batteries State of the art TES alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

The AMADEUS project “Next Generation Materials and Solid State Devices for Ultra High Temperature Energy Storage and Conversion” ü Project call: FET-Open ü 7 partners • 3 Universities • 3 R&D Centers • 1 SME ü Budget: 3. 270. 496, 25 € ü Duration: Jan 2017 – Dec 2019 ü Coordinator: UPM (Spain) Project coordinators: Prof. Antonio Marti – Dr. Alejandro Datas alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Latent Heat Thermal Energy Storage Carnot efficiency 82% 72% Boron 64% 54% Liquid Hydrogen Ultra-high temperature latent heat storage High temperature State of the art Solar salts (5 -20 $/k. Wh) Silicon (3. 5 $/k. Wh) AMADEUS novelty Pressurized Hydrogen (700 bar) Si-B alloys ü High latent heat ü High thermal conductivity Li-ion batteries State of the art TES alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Ultra-high temperature energy conversion Heat conduction /convection Ultra-High Temperature (UHT) Heat Radiation Radiative-based solid state converters 500 700 900 1100 1300 1500 1700 Temperature (⁰C) A. Datas, A. Martí, Thermophotovoltaic energy in space applications: Review and future potential, Solar Energy Materials and Solar Cells, Volume 161, March 2017, Pages 285 -296 alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Ultra-high temperature solid state converters Thermo-Photovoltaic (TPV) Thermionic (TIC) > 1000 ⁰C photons electrons + + - - - K. Aizat, et al. Review on Thermionic Energy Converters, IEEE Trans Elect Dev, Vol. 63, NO. 6, JUNE 2016 T. Bauer “Thermophotovoltaics: Basic principles and Critical aspects of System Design”, Springer. alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

TIC and TPV: advantages and limitations TIC: ü Power density > 10 W/cm 2 (>500 times solar PV’s) † Efficiency ~ 5 -12 % − Efficiency potential (= Carnot limit) TPV: † Power density ~ 2 -10 W/cm 2 (100 -500 times solar PV’s) ü Efficiency ~ 25% (@ 1100 ⁰C) − Efficiency potential (> 40%) ü Solid-state technology (no moving parts) AMADEUS novelty Hybrid Thermionic-Photovoltaic > 1000 ⁰C Hybrid thermionic-photovoltaic converter, by A. Datas. Appl. Phys. Lett. 108, 143503 (2016) electrons TIPV: Higher power density produced by the converter at intermediate temperatures (1580 -1780 K), typical of LHTES applications - + - photons + - alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Hybrid thermionic-photovoltaic converter (TIPV) Heat Emitter coating ü low workfunction ~ 3 e. V A (+) emitter / cathode p n TPV cell ü IR PV generation Microspacers ü vacuum micro-gap ~ 1 -3 µm (avoid space charge) Collector coating ü very low workfunction < 2 e. V ü transparent n- substrate Cooling B (-) alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Hybrid thermionic-photovoltaic converter (TIPV) Inverted 3 -terminal 2 -terminal A (+) emitter / cathode p n TPV cell emitter / cathode photon hole photon electron n- substrate (transparent) electron n- substrate B (-) hole C (+) alessandro. bellucci@ism. cnr. it www. amadeus-project. eu n p

Hybrid thermionic-photovoltaic converter (TIPV) 2 -terminal Inverted 3 -terminal A (+) thermionic photovoltaic B (-) C (+) alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

AMADEUS project: Thermionic converter Solutions and first developments Thermionic cathode Dielectric microspacers Collector Ba. F 2 ultra-thin layer directly on TPV surface Cathode Substrate Emitting layer La. B 6 thin film on W/Ta substrate Zirconia (Zr. O 2) microcolumns alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Thermionic converter Cathode and device characterization Φ = 2. 6 e. V A = 4. 62 A/cm 2 K 2 La. B 6 deposited by fs-PLD on Ta and W substrates XPS Black curve: experimental data Red curve: hypothesis ΦA = 1 e. V XRD alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

TPV cell Solutions and first developments Fabrication of In. Ga. As TPV cells Layer structure In. P I-V curves 0. 74 e. V In 0. 53 Ga 0. 47 As 70 A/cm 2 and 20 W/cm 2 alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

TPV cell 3 -terminals device characterization Fabrication of IBC TPV cells 10 x 10 mm 2 emitter / cathode n- substrate n p 5 x 5 mm 2 IBC TPV cell n-contact efficiency p-contact power alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Conclusions Towards the Po. C demonstration… § § Low cathode and anode work function Some µm gap required for TI Transparent anode required for TIPV integration Low temperature anode required (for TPV operations) After the first year of activities, some key-points have to be considered for demonstrating the TIPV device: • Ensure thermal stability and the suitable operating conditions of all the components for the application at 2000 °C • Obtain the condition ΦC› ΦA for a properation of the TIPV • Find the optimal design for In. Ga. As-based TPV anode • Evaluate the behaviour of the TIPV anode with respect to the cooling capacity of the system alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Project video alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Thank you for the attention alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Backup slides alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

AMADEUS Proof-of-concept alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Stability limit (~565 C) Temperature Hot Tank As high as possible Freezing point (~ 220 C) ΔT Cold Tank Stored energy E = m cp ΔT Typical ~ 100 k. Wh/m 3 Heat alessandro. bellucci@ism. cnr. it www. amadeus-project. eu

Temperature “Phase Change Materials” or PCM Solid Liquid Stored energy: E = m Lf Heat alessandro. bellucci@ism. cnr. it www. amadeus-project. eu