New Design of Solar Photovoltaic and Thermal Hybrid System for Performance Improvement of Solar Photovoltaic

© 2020 Ridwone Hossain et al. Solar photovoltaic (PV) and solar thermal systems are most widely used renewable energy technologies. Theoretical study indicates that the energy conversion efficiency of solar photovoltaic gets reduced about 0.3% when its temperature increases by 1°C. In this regard, solar PV and thermal (PVT) hybrid systems could be a solution to draw extra heat from the solar PV panel to improve its performance by reducing its temperature. Here, we have designed a new type of heat exchanger for solar PV and thermal (PVT) hybrid systems and have studied the performance of the system. The PVT system has been investigated in comparison with an identical solar PV panel at outdoor condition at Dhaka, Bangladesh. The experiments show that the average improvement of open circuit voltage (Voc) is 0.97 V and the highest improvement of Voc is 1.3 V. In addition, the overall improvement of output power of solar PV panel is 2.5 W

Enhancement of thermoelectric properties of La-doped SrTiO3 bulk by introducing nanoscale porosity

Electron-doped SrTiO3 is a well-known n-type thermoelectric material, although the figure of merit of SrTiO3 is still inferior compared with p-type metal oxide-based thermoelectric materials due to its high lattice thermal conductivity. In this study, we have used a different amount of the non-ionic surfactant F127 during sample preparation to introduce nanoscale porosities into bulk samples of La-doped SrTiO3. It has been observed that the porosities introduced into the bulk sample significantly improve the Seebeck coefficient and reduce the thermal conductivity by the charge carrier and phonon scattering respectively. Therefore, there is an overall enhancement in the power factor (PF) followed by a dimensionless figure of merit (zT) over a wide scale of temperature. The sample 20 at% La-doped SrTiO3 with 600 mg of F127 surfactant (SLTO 600F127) shows the maximum PF of 1.14 mW m−1 K−2 at 647 K which is 35% higher than the sample without porosity (SLTO 0F127), and the same sample (SLTO 600F127) shows the maximum value of zT is 0.32 at 968 K with an average enhancement of 62% in zT in comparison with the sample without porosity (SLTO 0F127)

XRD data

XRD pattern of La-doped SrTiO3 powder and bulk samples compare to the undoped SrTiO3

BET Analysis

Nitrogen gas absorption and pore size distribution data of samples, SLTO 200F127 and SLTO 600F12

compatibility factor

Compatibility factor of La-doped SrTiO3 samples for segmented thermoelectric la

Data of Thermoelectric Properties of La-doped SrTiO3 with Mesoporosity

Electrical conductivity, Seebeck coefficient, Power factor, Thermal Conductivity, Figure of merit (zT), Improvement of zT of La-doped SrTiO3 bulk material with mesoporosity

efficiency calculation of La-doped SrTiO3 bulk with mesoporosity

Conversion efficiency calculation of La-doped SrTiO3 with different amount of surfactant

Significant Improvement in Electrical Conductivity and Figure of Merit of Nanoarchitectured Porous SrTiO3 by La Doping Optimization

SrTiO3 is a well-studied n-type metal oxide based thermoelectric (TE) material. In this work, the first-principles calculation of La-doped SrTiO3 has been performed using the density functional theory. In addition, high TE properties of bulk SrTiO3 material have been achieved by introducing nanoscale porosity and optimizing carrier concentration by La doping. The X-ray diffraction, atomic resolution scanning transmission electron microscopy imaging, and energy-dispersive X-ray spectrometry results show that La has been doped successfully into the lattice. The scanning electron microscopy images confirm that all the samples have nearly similar nanoscale porosities. The significant enhancement of electrical conductivity over the broad temperature range has been observed through optimization of La doping. Additionally, the samples possess very low thermal conductivity, which is speculated because of the nanoscale porosity of the samples. Because of this dual mechanism of doping optimization and nanoscale porosity, there is a remarkable improvement in power factor, 1 mW/m2K from 650 to 800 K, and figure of merit, zT of 0.26 at 850 K, of the sample, 22 at. % La-doped SrTiO3

Significant improvement in electrical conductivity and figure of merit of nanoarchitectured porous SrTiO3 by la doping optimization

SrTiO3 is a well-studied n-type metal oxide based thermoelectric (TE) material. In this work, the first-principles calculation of La-doped SrTiO3 has been performed using the density functional theory. In addition, high TE properties of bulk SrTiO3 material have been achieved by introducing nanoscale porosity and optimizing carrier concentration by La doping. The X-ray diffraction, atomic resolution scanning transmission electron microscopy imaging, and energy-dispersive X-ray spectrometry results show that La has been doped successfully into the lattice. The scanning electron microscopy images confirm that all the samples have nearly similar nanoscale porosities. The significant enhancement of electrical conductivity over the broad temperature range has been observed through optimization of La doping. Additionally, the samples possess very low thermal conductivity, which is speculated because of the nanoscale porosity of the samples. Because of this dual mechanism of doping optimization and nanoscale porosity, there is a remarkable improvement in power factor, 1 mW/m2K from 650 to 800 K, and figure of merit, zT of 0.26 at 850 K, of the sample, 22 at. % La-doped SrTiO3