Two novel four-blade H-darrieus vertical axis wind turbines (VAWTs) have been proposed for enhancing self-start capability and power production. The two different airfoil types for the turbines are assessed: a cambered S815 airfoil and a symmetric NACA0018 airfoil. For the first novel wind turbine configuration, the Non-Similar Airfoils 1 (NSA-1), two NACA0018 airfoils, and two S815 airfoils are opposite to each other. For the second novel configuration (NSA-2), each of the S815 airfoils is opposite to one NACA0018 airfoil. Using computational fluid dynamics (CFD) simulations, static and dynamic conditions are evaluated to establish self-starting ability and the power coefficient, respectively. Dynamic stall investigation of each blade of the turbines shows that NACA0018 under dynamic stall impacts the turbine’s performance and the onset of dynamic stall decreases the power coefficient of the turbine significantly. The results show that NSA-2 followed by NSA-1 has good potential to improve the self-starting ability (13.3%) compared to the turbine with symmetric airfoils called HT-NACA0018. In terms of self-starting ability, NSA-2 not only can perform in about 66.67% of 360$°$ similar to the wind turbine with non-symmetric airfoils (named HT-S815) but the power coefficient of NSA-2 at the design tip speed ratio of 2.5 is also 4.5 times more than the power coefficient of HT-S815; the power coefficient difference between HT-NACA0018 and HT-S815 (=0.231) is decreased significantly when HT-S815 is replaced by NSA-2 (=0.076). These novel wind turbines are also simple.

An experimental setup is built to improve the charging process of a bio‐based phase change material inside a rectangular latent heat thermal energy storage (LHTES) system. In addition to experimenting with different porosities of full‐coverage wire mesh, a novel method of partial wire mesh placement at a proper location is used for improving conduction and maintaining natural convection, proven by the particle image velocimetry (PIV) method. Although acquiring PIV images from coconut oil is challenging because of the laser reflection, the image capturing and processing have been completed successfully. Temperatures inside the enclosure were measured using four K‐type thermocouples, and the melt fraction was calculated using captured images. The full‐size mesh results in a more uniform temperature distribution, and its charging time for porosities of 88% and 82% is decreased by 41% and 52%, respectively. The results of partial wire mesh placements indicate that a top‐only approach leads to a time reduction of only 7%. However, the bottom‐only approach yields a time reduction of 34% and the value of 3.8 for the charging time reduction over the porosity reduction parameter, which is the highest among all experiments. Additionally, this placement eliminates sudden temperature spikes, which improves the performance of the LHTES system and results in an economical and practical configuration. Moreover, the PIV test shows sustained convective velocities at the top half of the enclosure with a partial mesh at the bottom, demonstrating improved natural convection compared to that of a full‐size mesh implementation which weakens convection. Therefore, contrary to full‐size meshes used in previous works, a bottom‐only mesh placement can enhance conduction and convection simultaneously, which can be utilized in practical applications.