Summary One of the main challenges facing power generation by fuel cells involves the difficulties related to hydrogen storage. Several methods have been suggested and studied by researchers to overcome this problem. Among these methods, using fuel reformers as a component of the fuel cell system is a practical and promising alternative to hydrogen storage. Among many hydrogen carrier fuels used in reformers, methanol is one of the most attractive ones because of its distinctive properties. To design and improve of the methanol reformate gas fuel cell systems, different aspects such as promising market applications for reformate gas–fueled fuel cell systems, and catalysts for methanol reforming should be considered. Therefore, our goal in this paper is to provide a comprehensive overview on the past and recent studies regarding methanol reforming technologies, while considering different aspects of this topic. Firstly, different fuel reforming processes are briefly explained in the first section of the paper. Then properties of various fuels and reforming of these fuels are compared, and the characteristics of commercial reformate gas–fueled systems are presented. The main objective of the first section of the paper is to give information about studies and market applications related to reformation of various fuels to understand advantages and disadvantages of using various fuels for different practical applications. In the next sections of the paper, advancements in the methanol reforming technology are explained. The methanol reforming catalysts and reaction kinetics studies by various researchers are reviewed, and the advantages and disadvantages of each catalyst are discussed, followed by presenting the studies accomplished on different types of reformers. The effects of operating parameters on methanol reforming are also discussed. In the last section of this paper, methanol reformate gas–fueled fuel cell systems are reviewed. Overall, this review paper provides insight to researchers on what has been accomplished so far in the field of methanol reforming for fuel cell power generation applications to better plan the next stage of studies in this field.

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He received his Ph.D. degree from The University of Waterloo in 2012 in Mechanical Engineering, followed by one year work in the "Centre for Sustainable Energy Systems" at Ryerson University and one year in "Applied Nano-material & Clean Energy Lab." at the University of Waterloo as a Post-doctoral Fellow. He worked two years as a visitor researcher at the National Research Council (NRC) Canada during his Ph.D. He is currently actively working on several University-wide collaborations, funded project from State of Ohio, NASA, and National Science Foundation. He has more than 60 peer-reviewed journal and conference papers. His current research focuses are primarily on energy conversion & storage systems, energy saving in industry, energy materials, and measurements.

A geothermal heat exchanger (GHE) uses the geothermal energy for heating or cooling of residential places during winter or summer. Two different designs of GHEs, the straight-pipe and coiled-pipe designs, are evaluated in this study, and the effect of nanofluid as the working fluid is investigated. For this purpose, a mathematical model is developed, validated, and used to predict the temperature gain, heat gain, exergy gain, and pressure loss of the working fluid for different concentration of additive ceramic nanoparticles (Al2O3 and MgO) into the working fluid. It is shown that the coiled-pipe design has better performance compared to the straight-pipe design for GHEs. It also shown that how the temperature, heat gain and exergy gain change with increasing the additive nanoparticles into the base-fluid (water), while the pressure loss does not change significantly. The temperature gain increases about 60% when the volume fraction of nanoparticles in the base-fluid reaches 2%. This also helps to improve the natural circulation of working fluid and the GHE may not need a circulating pump to run at low flow rates. It is also shown that the additive MgO nanoparticles is more effective than Al2O3 nanoparticles to improve the GHE performance.