The purpose of this study is to introduce and demonstrate a fully automated process for optimizing the airfoil cross-section of a vertical-axis wind turbine (VAWT). The objective is to maximize the torque while enforcing typical wind turbine design constraints such as tip speed ratio, solidity, and blade profile. By fixing the tip speed ratio of the wind turbine, there exists an airfoil cross-section and solidity for which the torque can be maximized, requiring the development of an iterative design system. The design system required to maximize torque incorporates rapid geometry generation and automated hybrid mesh generation tools with viscous, unsteady computational fluid dynamics (CFD) simulation software. The flexibility and automation of the modular design and simulation system allows for it to easily be coupled with a parallel differential evolution algorithm used to obtain an optimized blade design that maximizes the efficiency of the wind turbine.

A one-step, gas-phase photothermocatalytic process for the synthesis of hydrocarbons, including liquid alkanes, aromatics, and oxygenates, with carbon numbers (C _n ) up to C ₁₃ , from CO ₂ and water is demonstrated in a flow photoreactor operating at elevated temperatures (180–200 °C) and pressures (1–6 bar) using a 5% cobalt on TiO ₂ catalyst and under UV irradiation. A parametric study of temperature, pressure, and partial pressure ratio revealed that temperatures in excess of 160 °C are needed to obtain the higher C _n products in quantity and that the product distribution shifts toward higher C _n products with increasing pressure. In the best run so far, over 13% by mass of the products were C ₅ + hydrocarbons and some of these, i.e., octane, are drop-in replacements for existing liquid hydrocarbons fuels. Dioxygen was detected in yields ranging between 64% and 150%. In principle, this tandem photochemical–thermochemical process, fitted with a photocatalyst better matched to the solar spectrum, could provide a cheap and direct method to produce liquid hydrocarbons from CO ₂ and water via a solar process which uses concentrated sunlight for both photochemical excitation to generate high-energy intermediates and heat to drive important thermochemical carbon-chain-forming reactions.

Aquatic biomass, especially algae, is a promising renewable energy resource, owing to its high growth rate, high oil content, and lack of competition with land needed for food crops. Both micro- and macroalgae can be converted to liquid fuel through pyrolysis; however, the high oxygen content of the oil results in a low calorific value. Co-pyrolysis of biomass with synthetic polymers can improve oil quantity and quality: the polymers are petroleum products, contain less oxygen, and provide a comparable high heating value to conventional fossil fuels. Polystyrene is a particularly attractive synthetic polymer, because it has the lowest recycling rate of the major categories of plastic. This article provides background concerning thermal conversion of biomass/organic waste to energy, focusing on pyrolysis. Advantages of algae and polystyrene as pyrolysis feedstocks are discussed, and previous pyrolysis studies of macroalgae and polystyrene, as well as co-pyrolysis studies of biomass and plastics, are reviewed.