Alon Lidor

National Renewable Energy Laboratory | NREL

Two-step thermochemical fuel production cycles powered using concentrating solar systems offer a route to convert solar energy to chemical fuels. In this work, we offer a critical assessment of the state of the art, a detailed technical analysis of this technology in terms of theoretical limitations and potential performance, and potential paths fo...

The production of drop-in liquid fuels via solar-driven thermochemical processes is a promising pathway for sustainable aviation and maritime sectors. The most important performance indicator is the solar-to-fuel energy efficiency, which is severely limited in a temperature-swing redox cycle without the application of heat recovery between the redu...

The solar splitting of H2O and CO2 via a thermochemical redox cycle offers a viable pathway for producing sustainable drop-in fuels for the transportation sectors. The key performance metric is its solar-to-fuel energy efficiency, which is strongly dependent on the ability to recover heat during the temperature swing between the reduction and oxida...

Solar thermochemical water splitting via a two-stage redox cycle has been subjected to numerous theoretical and experimental studies since a couple of decades. It has been considered as a promising technology to generate green hydrogen as it is feasible to directly convert concentrated solar radiation into storable chemical energy. The present arti...

This paper reports on the numerical analysis of a volumetric solar receiver-reactor for hydrogen production, using the 2-step reduction–oxidation cycle. A detailed parametric sweep covering hundreds of various parameter combinations is performed for a large solar reactor, using a transient physical model. We generate performance maps which are curr...

The combination of pressure swing adsorption (PSA) with a downstream redox chemical looping cycle to remove trace oxygen is proposed for the production of high-purity nitrogen from atmospheric air. The non-stoichiometric perovskite SrFeO3−δ is selected for the redox chemical looping cycle because of its favourable thermodynamics, rapid oxidation ki...

Hydrogen production by solar-driven 2-step reduction–oxidation cycles has been successfully demonstrated in recent years. While the demonstrated efficiencies were quite low (up to 5.25% solar-to-fuel efficiency), there is a large potential for much higher efficiencies. This paper presents a detailed parametric investigation of a large scale (>100 k...

We present here a novel explanation for the explosion limits phenomenon, based on the concept of thermodynamic stability analysis of the fuel-oxidizer mixture. This concept is demonstrated by a detailed statistical thermodynamic analysis of the explosion limits of the H2–O2 system. It is shown that while the magnitude of the relative fluctuations i...

We present a new model for the prediction of the explosion limits of the hydrogen-oxygen system. Our model is based on the principle of ignition delay time, postulating that crossing the explosion limit (by increasing the pressure or temperature above it) causes a sharp decrease in the ignition delay time. By using fundamentals of the chain ignitio...

A phase change material (PCM) open-cycle engine is a distinctive cycle that uses the ambient air as its hot reservoir and an on-board hydrogen storage as its cold reservoir. Here we present a new PCM open cycle engine, that is capable of overcoming two major problems of PCM engines: the significant energy losses at partial loads, and the power cont...

We propose a unified model for the three branches of the explosion limits of an H2–O2 mixture. By using different expressions for the ignition delay time at each limit, and by utilizing the Le-Chatelier rule, we obtain an analytical expression for the ignition delay time of the mixture. We show that by solving the time delay equation for a selected...

Explosion of fuel mixtures is an important and well known physical phenomenon. In our work, we investigate the explosion limits of a hydrogen-oxygen system,in regards to its 3-branches behavior. Unlike most studies to date, we investigate this phenomenon from a unified approach,taking into consideration the three different explosion limits with a s...

While there are many different challenges in the development of micro aerial vehicles (MAV), one of the severe limiting factors in terms of weight is the energy storage/power system. Most of the MAVs developed to date are based on electrical motors. In the present study, several potential alternative energy storage/power systems are examined, evalu...

Recent years have seen an increased effort in research and development of remotely-controlled and autonomous micro aerial vehicles (MAV). While there are many different challenges in the development of MAVs, one of the severe limiting factors in terms of weight is the energy source. Most of the MAVs developed up to date are based on electrochemical...