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All Journal International Journal of Renewable Energy Development
Najafi, Gholamhassan
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Chemistry Energy

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Analytical and Numerical Solution for H-type Darrieus Wind Turbine Performance at the Tip Speed Ratio of Below One Ghiasi, Pedram; Najafi, Gholamhassan; Ghobadian, Barat; Jafari, Ali
International Journal of Renewable Energy Development Vol 10, No 2 (2021): May 2021
Publisher : Center of Biomass & Renewable Energy, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ijred.2021.33169

Abstract

H-type Darrieus vertical axis wind turbines (VAWT) have omnidirectional movement capability and can get more power compared to other VAWTs at high tip speed ratios (𝜆). However, its disadvantages are self-starting inability and low generated power at 𝜆 less than 1. The performance of H-type Darrieus wind turbine at 𝜆<1 was studied using double multiple stream tube (DMST) model and two-dimensional computational fluid dynamic (CFD) simulation. In CFD simulation, the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations were used and the turbulence model was solved with SST k-ω model. The performance of fifteen various wind turbines was determined at fourteen wind velocities by two solution methods. The effect of chord length, solidity, Reynolds number and Height to Diameter (H/D) ratio were investigated on generated torque, power and the time required to reach 𝜆=0.1. Increasing in the moment of inertia due to the increasing in required time to reach 𝜆=0.1. In the low TSRs, the wind turbines can generate higher torque and power in high Re numbers and solidities. The required time was reduced by an increase in Re number and solidity. Finally, the best ratio of H/D of H-type Darrieus wind turbines was defined to improve the turbine performance.
Sustainable Design of a Near-Zero-Emissions Building Assisted by a Smart Hybrid Renewable Microgrid Esmaeili Shayan, Mostafa; Najafi, Gholamhassan; Ghobadian, Barat; Gorjian, Shiva; Mazlan, Mohamed
International Journal of Renewable Energy Development Vol 11, No 2 (2022): May 2022
Publisher : Center of Biomass & Renewable Energy, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ijred.2022.43838

Abstract

Renewable energy regulations place a premium on both the use of renewable energy sources and energy efficiency improvements. One of the growing milestones in building construction is the invention of green cottages. Building Integrated Photovoltaic (BIPV) technologies have been proved to aid buildings that partially meet their energy demand as sustainable solar energy generating technologies throughout the previous decade. Curved facades provide a challenge for typical photovoltaics. This study designed, produced, and assessed elastic solar panels supported by flexible photovoltaic systems (FPVS) on a 1 m2 layer. The LabVIEW program recognizes and transmits online data on warm and dry climates. The fill factor was 88% and 84%, respectively, when installed on the silo and biogas surfaces. The annual energy output was 810 kWh on a flat surface, 960 kWh on a cylindrical surface, and 1000 kWh on a hemisphere surface. Economic analysis indicates that the NPV at Flat surface is $ 697.52, with an IRR of 34.81% and an 8.5-year capital return period. Cylindrical surfaces and hemispheres both get a $ 955.18 increase. For cylindrical and hemispheric buildings, the investment yield was 39.29% and 40.47%, respectively. A 20% increase in fixed investment boosted the IRR by 21.3% in the flat system. While the cylindrical system had a 25.59% raise, the hemisphere saw a 24.58% gain
Co-Authors Ali Jafari, Ali Esmaeili Shayan, Mostafa Ghiasi, Pedram Ghobadian, Barat Gorjian, Shiva Mazlan, Mohamed