Grantee Research Project Results
Final Report: Harnessing wind energy to improve grain safety from aflatoxin contamination
EPA Grant Number: SU839285Title: Harnessing wind energy to improve grain safety from aflatoxin contamination
Investigators: Adedeji, Akinbode , Agbali, Francis , Cline, David , Mays, John , Omodara, Michael , Mahoney, Chase
Institution: University of Kentucky
EPA Project Officer: Page, Angela
Phase: I
Project Period: November 1, 2017 through October 31, 2018
Project Amount: $14,956
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2017) RFA Text | Recipients Lists
Research Category: P3 Awards , Sustainable and Healthy Communities , P3 Challenge Area - Air Quality
Objective:
The prototype design started by considering vertical versus horizontal wind turbine systems Fig. 1. Based on the result of power harnessable from each system determined by measuring the rpm (anemometer) and torque (dynamometer), and then calculating the power, a design was chosen for testing.
Figure 1:Perspective drawing of the four wind turbine tested: 3-vane vertical axis wind turbine, 3VVAWT (A); 4 -vane vertical axis wind turbine, 4VVAWT (B); enclosed 4 -vane vertical axis wind turbine, E4VVAWT; (C) and horizontal axis wind turbine, HAWT (D).
The wind turbine was coupled with an axial fan and its capacity for aeration at different wind speed was tested by introducing forced air generated by the fan into a cut-scale drying bed with a dimension of 0.5m x 0.5m x 1.0m. Test was carried out at 4 wind speeds between 2.5 and 7 m/s, which depict typical wind speed in the savannah (middle belt) region of Nigeria that is selected as an example of a sub-Saharan agricultural (SSA) grain production area. At the inlet of the drying system, the volumetric flow rate and static pressure were measured using an anemometer and static pressure probe, respectively. Results are shown in Figure 2 below. The efficiency of the system in terms of power in the generated forced air as a function of the flowrate at the drying system inlet versus the power in the wind turbine as a function of the torque and rpm of the turbine was determined.
Summary/Accomplishments (Outputs/Outcomes):
The estimated maximum power output from the four wind turbine designs (3VVAWT, 4VVAWT, E4VVAWT and HAWT) with a blade span of 0.6 m at 6 m/s wind speed are 25, 11.5, 7.5 and 19 W, respectively (Figure 2). Even though 3VVAWT showed higher power but it could not function below 4.5 m/s wind speed. This implies during low wind speed weather, this system will have zero power output. We therefore decided to focus on the HAWT with consistent power output between 2.5 – 7.0 m/s we are designing for.
Figure 2: (Right), plot of wind speed against power generated by the 4 designs of wind of wind turbine; (Left), airflow rate against static pressure. 6:10, 6:5 & 6:4 are ratios of the pulleys on the turbine shaft to the shaft driving the axial fan for forced air generation.
With an axial fan connected to the shaft being driven by the turbine, a flow rate and static pressure in the range of 0.3 – 1.4 m3/s and 0.75 – 3.99 Pa, respectively, were measured. Power in the forced air was determined as function of flow rate and static head. Using mean air density at 35°C, a temperature representative of harvest time in SS--\, the swept area of the turbine blade (n*[0.6t'2 ) and the wind speed between 2 – 6.7 m/s and the efficiency factor (0.593*0.8), the power harnessable from the wind was determined. The empirical power obtained from torque and airflow rate and from Betz equation (Power = ½*swept area*air density*wind speed'3*Betz limit [0.593t) were within the limit of each other. Therefore the efficiency (Y) of the system as a function of the power in the turbine was determined as the power in the forced air divided by the turbine power from Betz equation. The results indicates it is possible to generate forced air through mechanical transfer of energy from wind to air with an efficiency of about 20.03%. Note that if the dimension of the turbine is doubled, the power/Y output quadruples. Our final goal in Phase I is to test the efficacy of the system in a drying study and determine its economic feasibility by the end of the end of Phase I in October, 2018.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this projectSupplemental Keywords:
Wind, Green Energy, Aflatoxin, Grains, Forced Air, Drying.Relevant Websites:
UK Student Project has Potential to Make International Impact Exit
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.