2/10 Weekly Brief

Design

• Hydrology
• This team is primarily researching weir design.  The book “Designing and Building Mini and Micro Hydropower Schemes” provides several example designs, but does not seem to suggest a specific type of weir given the location. Rough sketches of possible designs were completed and several MathCad documents were created that will generate critical numbers as soon as specific parameters are input.  Goal for this next week is to have a design chosen for the weir.  
• Geotechnical
• Landslides pose a serious threat to safety and construction in Cameroon. Because the soils in the village of Bangang are largely comprised of clays and silts, the water content of the soil has a large bearing on the soil's behavior. Several factors may contribute to landslides in West Cameroon. These include the amount of rainfall, the frequency at which the rain falls, seismic activity (tectonic or volcanic in origin), erosion formed mechanically by mudslides, and anthropogenic factors such as ridging across slopes for farmland, removing vegetation covers, and destroying the cohesion of the soil. There are a number of methods that may be applied in areas prone to landslides that reduce the potential for such disasters. Improving the drainage of both the surface and subsurface may prevent the soil from becoming weakened by excess amounts of water. Also, flattening the slope of a particular area by either removing soil from high elevations or increasing the amount of soil at lower elevations can be effective in mediating landslides. Other possible solutions include the construction of piles and retaining walls, removal and replacement of particular soils, preservation or introduction of vegetation to hold the soil in place, and fencing or netting for large rocks if any are present at high elevations.
• Questions to consider:
• What are the steepest slopes in the area we will be working in?
• What kind of farming is practiced in the area?
• How close is the nearest volcano and fault line?
• What is the volcano's classification?
• What color is the soil?
• What is the soil's optimal water content?
• Mechanical
• Problem statement: In the current hydropower turbine design, the water intake regulator has to be adjusted manually to ensure that the power output from the turbine does not exceed the maximum load imposed by the electrical hardware surrounding it
• Objective: Implement a system that automatically controls the teardrop regulator so that a constant power output is generated
• System:
• Pre-filter: Necessity dependant on quality of input signal
• Input: Desired Power (kW)
• Controller: PID Controller -- Relationship between-power generated, teardrop regulator angle, threaded rod revolutions
• Actuator: Stepper motor -- rotates threaded rod
• Plant: Hydropower turbine
• Sensor: Wattmeter
• Output: Actual power (kW)
• Questions
• How is the current power output from the turbine regulated?
• What happens if the power output is above or below the set limit?
• Tasks for next week
• Determine micro-controller to be used
• Arduino
• Other
• Determine motor requirements
• Type
• Power output required
• Power input available
• Power distribution
• Worked on finding the best way to map the area. If GIS is to be used, time will be a big factor. We cannot afford to look in-depth at the possibility of GIS this semester. Instead, Google Earth will serve as an alternative until a proficient GIS user is on the team in a future semester.
• Searched for a power simulation software, though many options are unavailable to this team member with a Mac OS system. Contacted the software developer (ETAP) about possible Mac version and to inquire about pricing -- still waiting to hear back.
• Questions to consider:
• The map for the village includes so many houses, but is it correct that this preliminary design will be intended for the first 20 houses currently connected before moving on to an expansion? If so, these houses should be identified as soon as possible.
• What is the expected power generated by the hydropower turbine?
• Is this system going to supply hospitals, schools, stores, or any things other than houses? If so, typical electricity usage for these facilities should be identified as well.

Assessment

• Environmental Impact
• Reviewed UNDP Climate Change Country Profile
• Largest variable caused by climate change is increased sporadic rainfall in the area
• Contacted Dr. Laura Bowling from Agronomy to discuss water quality issues; specifically regarding information about how climate change and intense rainfall events affect the water level and how these are impacted by the hydropower turbine.
• Identified several additional EIA articles
• Social Impact
• Designed detailed work-plan for the SIA and reviewed with team
• By Feb 20: writing 3-4 page summary of the pros and cons of micro-hydropower development
• Economic

• One of the most important elements for the operation of a micro hydropower plant is the electro-mechanical equipment (turbine-alternator). This equipment typically incurs 30-40% of the total cost and could therefore directly impact the feasibility of a project. In several studies, the investment cost per kW is presented as a function of installed capacity and head. Although there is hight variation in the presented costs among different studies, in most cases, the unit cost for small hydropower plants is much higher compared to the unit cost for larger power ranges. 

• Construction Management
• NA