Query: Improved Design of a Thermophotovoltaic Device

Candidate papers:

abstract: In this article, we further study the parametric optimum design of a far field thermophotovoltaic device (FTPD) that consists of a radiator and a photovoltaic (PV) cell. These two basic components are made of hexagonal boron nitride (hBN) and narrowband semiconductor, respectively. The irreversible radiative and nonradiative recombination losses within the PV cell are considered. Expressions for the power density and energy conversion efficiency of the FTPD are given. The maximum power density and efficiency of the FTPD are calculated numerically for the given output voltage and the thickness of the PV cell. Making tradeoffs between the power density and the efficiency, the optimum regions of some key performance parameters are provided. The optimum operating conditions of FTPDs for three different semiconductors are presented. The effects of the radiator temperature on the optimum performances of FTPDs are discussed. The results may provide optimal design strategies for the practical manufacture of FTPDs.
author_names: Tianjun Liao

Houcheng Zhang

Zhi-Yong Wang
title: Improved Design of a Thermophotovoltaic Device
venue: IEEE Transactions on Electron Devices
year: 2020

abstract: An In0.68Ga0.32As thermophotovoltaic (TPV) cell on a compositionally nonmonotonically graded InAsP buffer with a band gap energy of 0.60 eV grown by metal organic chemical vapor deposition (MOCVD) has been fabricated. The performance of the TPV device was greatly improved with optimized material growth, the use of an absorption layer of suitable width, and appropriate TiO2/SiO2 antireflective coating design. Under standard AM1.5G spectra, the open circuit voltage (Voc) increases from 0.19 to 0.23 V, the short circuit current density (Jsc) increases from 43 to 56 mA/cm2, and the conversion efficiency increases from 5.31 to 8.06% By illumination at a high intensity of 50 suns, a high conversion efficiency of 12.3% with a Voc of 0.35 V is reached.
author_names: Tan Shu Ming

Shulong Lu

Lian Ji

Yaqi Zhu

Zhiming Chen
title: Optimization of In0.68Ga0.32As Thermophotovoltaic Device Grown on Compositionally Nonmonotonically Graded InAsP Buffer by Metal Organic Chemical Vapor Deposition
year: 2013

abstract: Solar thermophotovoltaic (STPV) devices provide conversion of solar energy to electrical energy through the use of an intermediate absorber/emitter module, which converts the broad solar spectrum to a tailored spectrum that is emitted towards a photovoltaic cell [1] While the use of an absorber/emitter device could potentially overcome the Shockley Queisser limit of photovoltaic conversion [2] it also increases the number of heat loss mechanisms. One of the most prohibitive aspects of STPV conversion is the thermal transfer efficiency, which is a measure of how well solar energy is delivered to the emitter. Although reported thermophotovoltaic efficiencies (thermal to electric) have exceeded 10% [3] [4] previously measured STPV conversion efficiencies are below 1% [5] [6] [7].In this work, we present the design and characterization of a nanostructured absorber for use in a planar STPV device with a high emitter to absorber area ratio. We used a process for spatially selective growth of vertically aligned multi walled carbon nanotube (MWCNT) forests on highly reflective, smooth tungsten (W) surfaces. We implemented these MWCNT/W absorbers in a TPV system with a one dimensional photonic crystal emitter, which was spectrally paired with a low bandgap PV cell. A high fidelity, system level model of the radiative transfer in the device was experimentally validated and used to optimize the absorber surface geometry. For an operating temperature of approximately 1200 K, we experimentally demonstrated a 100% increase in overall STPV efficiency using a 4 to 1 emitter to absorber area ratio (relative to a 1 to 1 area ratio) due to improved thermal transfer efficiency. By further increasing the solar concentration incident on the absorber surface, increased emitter to absorber area ratios will improve both thermal transfer and overall efficiencies for these planar devices.(c) 2013 ASME
author_names: David M Bierman

Andrej Lenert

Evelyn N Wang
title: Improved Thermal Transfer Efficiency for Planar Solar Thermophotovoltaic Devices
year: 2013

abstract: The present theory integrates all components of a thermophotovoltaic (TPV) device (i.e. the primary lens, the absorber, the photovoltaic (PV) cell and a photon recuperator system) Energy balances are derived for the absorber and PV cell. The TPV efficiency is maximized by using three optimization parameters, namely, absorber temperature, PV cell temperature and cell voltage. An ad hoc numerical constraint optimization procedure is developed which allows computation of an optimum absorber temperature within 5 10 K error. In case of an improved thermal design, the 'ideal' bandgap for TPV solar energy conversion is in the range 0.5 1 eV, in reasonable good agreement with present knowledge. Further improvement in thermal design quality moves the optimum bandgap toward higher values. Improving thermal design quality decreases the influence of the concentration ratio, on both optimum absorber temperature and optimum PV cell voltage. An improved thermal design allows almost all narrow bandgap materials to operate at positive voltage. The results prove existence of an optimum concentration ratio.
author_names: Viorel Badescu
title: Thermal design influence on the performance of solar thermophotovoltaic devices
year: 2003

abstract: InGaAsSb and GaSb thermophotovoltaic cells were grown lattice matched to GaSb substrates epitaxially by the Molecular Beam Epitaxy (MBE) method and fabricated non epitaxially using ion implantation. TPV cells with 1 x 1 cm dimensions were fabricated. External quantum efficiencies and device characteristics including open circuit voltage, short circuit current density, ideality factor and reverse saturation current density of the TPYs were measured and compared. For the quaternary MBE grown InGaAsSb, obtaining high Voc was challenging due to the low shunt resistance caused by growth defects in the relatively thick epitaxial design. However, this TPV demonstrated promising fundamental deuce parameters since the lowest ideality factor and reverse saturation current density were observed compared to the others. The MBE grown GaSb TPV structures had an order of magnitude thinner epitaxy and improved shunt resistance. The implanted GaSb TPYs exhibited similar performance to the MBE TPYs indicating that implant induced damage was not a limiting factor.
author_names: Nassim Rahimi

Daniel J Henera

Shaimaa A Abdallah

Veronika Stelmakh

Walker R Chan

Ivan Celanovic

Luke F Lester
title: Epitaxial and non epitaxial large area GaSb based thermophotovoltaic (TPV) cells
venue: 2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC)
year: 2015

abstract: We propose quantum cascade thermophotovoltaic structures based on intersubband transition for efficient energy conversion using GaN/AIN material system. Four designed structures combinedly absorb a broad range of blackbody spectrum from 1300 K to 2000 K, including higher energy portion of the blackbody radiation. Optimized design of relaxation path ensures efficient collection of photoexcited carriers at the device terminals, and hence, greater current density and improved device efficiency.
author_names: Sakib Hassan

Muhammad Anisuzzaman Talukder
title: Increased radiation absorption in thermophotovoltaic quantum cascade structures
venue: 2015 IEEE International Conference on Telecommunications and Photonics (ICTP)
year: 2015

abstract: Capturing waste heat as electricity using solid state microelectronics has potential benefits for a wide variety of applications. Davids et al. recently reported a 3 terminal CMOS dual tunnel diode device demonstrating power generation up to 61 mW/cm2 at 350degC. Compared to prior rectenna designs, this design experimentally demonstrates 6,800 times higher power densities, for efficiencies around 7x10 3% The enhancement may be attributed to improved rectification or to a shift to a thermophotovoltaic design; making this distinction clearly warrants further study. This work suggests that significant further improvements in solid state conversion efficiencies are still possible. Ultimately, this research direction may enable more economic recovery of waste heat in data centers, communications, radars, ground transportation, combined heat and power plants, and more.
author_names: Peter Bermel
title: Capturing Waste Heat with CMOS Microelectronics
year: 2020

abstract: The recent interest in thermophotovoltaics (TPV) for space power applications has necessitated consideration of new device designs that are optimized for operation at elevated temperatures in order to be compatible with practical space platform power systems. Photovoltaic device performance degrades as operating temperature is increased due to increasing dark current density (Jo) A cooling system is therefore required to maintain a low cell temperature with respect to the emitter ~1300 K) However, the cold side cooling capacity is directly related to the temperature, size and mass of a passive radiator. Therefore, since a high power to weight ratio is a critical factor for spacecraft power system design, the ability to realize devices capable of improved power density at elevated temperatures is critical to minimize the mass of space TPV systems. A simple model has been developed to estimate the effect of temperature on device electrical properties. Design parameters under investigation are the modific.
author_names: Fred Newman

Susan L Murray

Scott Endicter

Daniel J Aiken

G R Girard

Michele Turner

Paul R Sharps
title: Development of Thermophotovoltaic Devices Optimized for High Temperature Operation
year: 2005

abstract: A new testing platform for semiconductor solar devices and solar concentration applications has been developed. By separating the solar radiation into two beams using a dichroic lens, simultaneous operation of a photovoltaic (PV) and a thermophotovoltaic (TPV) cell is made possible. Photons with a wavelength shorter than 1100 nm are reflected onto a PV cell; whereas the remaining solar spectrum is refracted towards a TPV cell. This testing platform takes advantage of auto tracking and focusing capabilities using a digital mount and photoresistors. Alternative solutions to cooling problems have also been offered. Various concentration ratios, incident light intensities, acceptance angles and spot sizes can be achieved due to the versatile nature of this device. Issues with mismatching lattice constants have also been addressed through spectrum splitting. This design, when operated at its full capacity with a 3 junction PV cell and a TPV cell, allows for exciting new possibilities in high efficiency solar cell technology. These possibilities include the 3+1 hybrid multijunction cell design which could lead to higher overall efficiencies than conventional concentrators.
author_names: Emir Salih Magden

Han-Ting Chen

Chandler Downs

Thomas E Vandervelde
title: 3+1 multijunction testing and operations platform for improved PV and TPV efficiencies
venue: 2010 IEEE Conference on Innovative Technologies for an Efficient and Reliable Electricity Supply
year: 2010

abstract: Thermophotovoltaic and rectenna devices can be greatly improved by frequency selective emitters, which narrow the emission spectrum of a heat source to couple to the most efficient operating point of the device. We have simulated an alumina and titanium emitter using a Fabry Perot design which is intended for use with thermal energy converters operating in the near to mid infrared region.
author_names: John Chivers

Thomas E Vandervelde
title: Broad area, selective emitters for high temperature operation
venue: 2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS)
year: 2017