|
The editorial introduces the JPE Special Section on Thermophotovoltaic Systems for Volume 14 Issue 4. |
|
The concept of thermophotovoltaics (TPV), converting heat into electricity via photovoltaic cells, originated in the 1960s, yet very recently the field has experienced significant advances. Thanks to breakthroughs in nanofabrication, materials science, and instrumentation, TPV technology is emerging as a viable solution for sustainable energy production, with strong connections to photovoltaics and other renewables, as well as thermal energy storage. The integration of high-quality III-V semiconductor materials and innovative photovoltaic (PV) cell designs has reignited scientific interest and increased the market potential of TPV systems. At the core of this resurgence is the ability to precisely control thermal radiation, a feat that connects disciplines such as nanophotonics, semiconductor physics, and materials science. By tailoring thermal emission, researchers can optimize TPV performance, making these systems more efficient and versatile. Thermophotovoltaics show promise in both large-scale energy storage and recycling low-grade waste heat. By using TPV technology, stored high-temperature heat can be converted into electricity during periods of low energy supply, while TPV systems also provide a means to directly harness solar heat. The field’s maturation is evident in the formation of a global research community, as seen in international conferences like the recent 15th World Conference on Thermophotovoltaic Generation of Electricity, held in Madrid, Spain, from 30 September to 3 October 2024. With increasing focus on tackling the world’s energy demands sustainably, TPV research is shifting into a new era. The current issue of Journal of Photonics for Energy (JPE) features a Special Section on Thermophotovoltaic Systems, to highlight fundamental and applied advancements, spanning topics from thermal emission materials and photon management to novel TPV applications in space and waste heat recovery. This renewed momentum underscores the potential of thermophotovoltaics to play a key role in a more energy-efficient future, driving innovation across multiple sectors. The convergence of TPV technology with other emerging energy solutions offers a glimpse of an exciting path forward in the pursuit of sustainable energy alternatives. In this JPE special section, a techno-economic analysis of a solar thermophotovoltaic system for a residential building is provided by Manish Mosalpuri, Fatima Toor, and Mark Mba-Wright. They predict a decrease by $0.128/kWh in levelized cost of consumed electricity with the employment of residential TPVs, showcasing the feasibility and technological relevance of TPVs. New findings in materials design are also reported, for example in the work “ Temperature-dependent optical dispersion of composite cerium oxide and varium zirconate single layers and multi-layers” by Changkyun Lee, Jie Zhu, Jiawei Song, Haiyan Wang, Xiulin Ruan, and Peter Bermel, reporting good thermal stability and wavelength-selectivity in thermal emission which is crucial for TPV emitters, as well as in “ Smart window based on integration of nanoporous microparticles in liquid crystal composite with metamaterial nanostructured VO2 film” by Sofiia Barinova, Saranya Bhupathi, Peter Kazansky, Yi Long, and Ibrahim Abdulhalim, where a combination of nematic liquid crystals with nanoporous nanoparticles in windows is shown to yield simultaneous control of visible- and infrared-frequency transmissivity, relevant for controlling visibility and the influx of heat, respectively. To harvest solar heat for TPV and other applications, the paper entitled “ Ultra-broadband perfect solar absorber based on V2O5-TiN-V2O5 nanodisc and TiN nanopillar array structures” by Weiye He and colleagues reports that combining vanadium oxide and titanium nitride provides for broad-band solar absorption with high thermal conversion efficiencies up to at least 800 K. Finally, two independent works discuss the trade-off between pair-wise efficiency and electrical power density of TPV systems. In the work “ Thermodynamic figure of merit for thermophotovoltaics” by Maxime Giteau, Michela Picardi, and Georgia Papadakis, a new figure of merit is introduced that quantifies how far from their thermodynamic performance limits lie recent reported far-field TPV experimental results, whereas in the work “ Main performance metrics of thermophotovoltaic devices: analyzing the state of the art” by Basile Roux, Christophe Lucchesi, Jean-Philippe Perez, Pierre-Olivier Chapuis, and Rodolphe Vaillon, the link between optical cell band gap and emitter temperature is identified, and it is revealed that the majority of recent far-field TPV experiments are not conducted near the maximum power point, but rather are designed to optimize conversion efficiency. BiographyPeter Bermel is the Elmore Professor of Electrical and Computer Engineering at Purdue University. He received his PhD in physics from MIT in 2007. His research focuses on improving the performance of thermophotovoltaics, photovoltaics, and microelectronics using the principles of nanophotonics. Key enabling techniques for his work include electromagnetic and electronic theory, modeling, simulation, fabrication, and characterization. Georgia T. Papadakis received her PhD in applied physics from the California Institute of Technology in 2018 and continued her studies at Stanford University, where she was awarded the TomKat Fellowship in Sustainable Energy until 2021. Since 2021, Georgia is a group leader and tenure-track professor at the Institute of Photonic Sciences (ICFO) in Barcelona, Spain, where she leads the Thermal Photonics Group. Her research lies at the intersection of mid-infrared materials and metamaterials design characterization, active control of thermal radiation for application in lighting and sensing, and thermophotovoltaic systems. Eric Tervo is an assistant professor of electrical & computer engineering and of mechanical engineering at the University of Wisconsin – Madison. He received his PhD in mechanical engineering from the Georgia Institute of Technology in 2019 and was the Nozik Director’s Postdoctoral Fellow at the National Renewable Energy Laboratory until 2022. His research focuses on developing semiconductor materials and devices for energy conversion and thermal management through the study of combined heat, light, and charge transfer processes. Esther López is an associate professor at the Universidad Politécnica de Madrid (UPM) and received her PhD in photovoltaic solar energy from the UPM in 2016. Nowadays her research focuses on developing TPV devices and systems for energy generation and storage. Since 2021, she is also one of the co-founders of the spin-off THERMOPHOTON, whose objective is to design, produce, and commercialize those TPV systems. Brendan Kayes heads the Heat-to-Power R&D team at Antora Energy. In this role he works on Antora’s combined-heat-and-power thermal battery product, which uses thermophotovoltaics to convert stored heat into on-demand electricity. Prior to Antora, he worked at Alta Devices, where he led the team that established the current single-junction non-concentrator solar cell efficiency world record of 29.1%. He received his PhD in applied physics from the California Institute of Technology in 2009. |
