Integrating a redox flow battery into a Z-scheme water splitting system for enhancing the solar energy conversion efficiency

2019 ◽  
Vol 12 (2) ◽  
pp. 631-639 ◽  
Author(s):  
Zhen Li ◽  
Wangyin Wang ◽  
Shichao Liao ◽  
Mingyao Liu ◽  
Yu Qi ◽  
...  
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Water Splitting ◽  
Conversion Efficiency ◽  
Solar Energy Conversion ◽  
Energy Conversion Efficiency ◽  
Hydrogen Energy ◽  
Redox Flow Battery ◽  
Solar Energy Conversion Efficiency ◽  
Splitting System

A RFB-integrated Z-scheme water splitting system produces hydrogen energy and electricity for efficient solar energy conversion.

Symbiotic Cultures for Increasing the Solar Energy Conversion Efficiency of Outdoor Photobioreactors

2009 ◽  
Author(s):  
Halil Berberog˘lu ◽  
Laurent Pilon
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Solar Energy Conversion ◽  
Energy Conversion Efficiency ◽  
Incident Radiation ◽  
Hydrogen Energy ◽  
Radiation Characteristics ◽  
Photochemical Process ◽  
Solar Energy Conversion Efficiency

A numerical study is presented aiming to maximize the solar to hydrogen energy conversion efficiency of a symbiotic culture containing microorganisms with different absorption characteristics. The green algae Chlamydomonas reinhardtii CC125 and the purple non-sulfur bacteria Rhodobacter sphearoides ATCC 49419 are chosen for illustration purposes. The previously measured radiation characteristics of each microorganism are used as input parameters in the radiative transport equation for calculating the local spectral incident radiation within a flat panel photobioreactor. The specific hydrogen production rate for each microorganism as a function of the available incident radiation is recovered from data reported in the literature. The overall solar to hydrogen energy conversion efficiency of symbiotic cultures of varying microorganism concentrations have been computed for photobioreactor thicknesses from 1 to 10 cm. The results show that for a given photobioreactor thickness a saturation microorganism concentration exists above which the solar energy conversion efficiency does not increase. The maximum solar energy conversion efficiencies of solo cultures of C. reinhardtii and R. spaheroides at their respective saturation concentrations are 0.06 and 0.055%, respectively. Using symbiotic cultures, a total conversion efficiency of about 0.075% is achieved within the parameter range explored. It has been shown that the choice of microorganism concentrations for maximum solar energy conversion efficiency is non-trivial and requires careful radiation transfer analysis coupled with H2 production kinetics taking into account the photobioreactor thickness. The presented numerical tool can be used for simulating any photobiological or photochemical process involving more than one species with different radiation characteristics provided the closure laws for the reaction kinetics are known as a function of spectral incident radiation. Examples include (i) the symbiotic cultivation of more than one microorganism for biomass or lipid production in a photobioreactor and (ii) a photochemical reactor containing a number of absorbing and scattering photocatalysts with different band gaps.

scholarly journals TiO2 nanotubes with ultrathin walls for enhanced water splitting

2015 ◽  
Vol 51 (63) ◽  
pp. 12617-12620 ◽  
Author(s):  
Ahmad M. Mohamed ◽  
Amina S. Aljaber ◽  
Siham Y. AlQaradawi ◽  
Nageh K. Allam
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Water Splitting ◽  
Conversion Efficiency ◽  
Wall Thickness ◽  
Tio2 Nanotubes ◽  
Solar Energy Conversion ◽  
Energy Conversion Efficiency ◽  
Solar Energy Conversion Efficiency

Nanotube wall thickness determines its solar energy conversion efficiency.

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