2/17 Weekly Brief

Design

• Hydrology
• Last week was spent working on the design for the intake weir.  More resources were found and a sketch of the top-down view of the intake location was found.  Equations have been set up in Mathcad documents but calculations cannot be complete until more information is known.
• Questions to consider:
• Do we have a cross section of the river where the weir needs to be placed? If not, what is the approximate depth?
• What is the average river velocity?
• There was once mention of the religious and cultural constraints on using the total water supply to power the turbine. Is this a factor in our design? If so, what kind of constraints does this place on the amount of water which can be diverted?
• Are there pictures of the river itself?
• Geotechnical

• During the summer months, when rain fall increases, the chance of landslides also increases substantially. Clays and silts are effected greatly by this fluctuation as their properties change at various water contents. Compaction of soil for the foundation of civil works such as the weir is an essential component of creating long lasting structures. The weir allows for control of the water flow rate as it navigates to the turbine.  If this structure fails, the energy supply may be interrupted and damage to the entire system is a possibility.

• Questions to consider:
• What material will be used for the weir?
• What is the height of the water is falling to get to the turbine?
• How much water/what is the depth of water behind the weir expected to be?
• How far away from the turbine is the weir being installed?
• What is the natural flow rate of the river (probably varies widely with rainfall)
• Is water for drinking taken directly from the river?
• Does the river water get extremely thick or muddy? If so, how does this effect the turbine?
• Mechanical
• 
  
• Power distribution
• For this week, the team worked primarily on three parts: loads, mapping, and line configuration.
• First, the information given by ACREST was used to calculate the maximum load. According to ACREST, the typical use of electricity per household is four lamps, a phone charger, and a radio. From this information, the load per household was calculated as 300W and the load for the 20 households as 6 kW. The load for ACREST machines is still needed to be calculated; however, not enough information is yet known about them; assumptions will be made. Two main points should be noted about these calculations:
• The calculations are for the maximum load and do not include the energy losses.
• Google earth was chosen as the most ideal mapping program for this semester (GIS in the future, when more experienced GIS users are on the team)
• Therefore, the map from ACREST was translated into English and used to organize the input so that it would be easily understood. Finally, the team learned from the textbook about different types of line configuration. Because the grid system will be growing, it was concluded that the best line configuration for our system is a single phase, two lines even though its cost is higher than the other line configuration. A single phase, two lines has the potential to add more lines to switch to another line configuration, and by doing so, the capacity would increase by 2 to 4 times, depending on the line distribution. However, if the village already uses the single phase, two lines, an upgrade might be considered to a higher configuration if budget is limited.
• For the next week, first I am hoping to collect more information about the electricity use to improve my estimated calculation for the load. Second, I will type my work for the load and line configuration and make them available at the Google Drive. Third, I will continue reading the textbook to learn about conductors and start comparing different type of them. Choosing conductors seems a complicated task, so most likely it will take more than one week.
• Questions to consider:
• Locations of the houses that will be in the grid system
• Power consumption of ACREST machines (power, current, voltage, power factor)
• Line configuration currently used in the village
• Information about the conductors used in the current grid system

Assessment

• Environmental Impact
• Ecological impact of micro-hydropower is minimal. However, these effects can be magnified when the stream is small due to a part of the stream being diverted from its natural flow. Stream flow minima are set by the United States Environmental Agency in order to make sure that the ecosystem of the river is not affected.
• Main effects of hydropower ecologically impact plankton and algae. This would trigger a bottom-up cascade effect. The cascade effect could then effect vertebra, fish, birds, and ultimately people.However, most hydropower plants that have impacted the ecosystem have done so in a negative way. 
• Questions to consider:
• Is the area agriculturally active? If so, what kinds of crops are grown in the area?
• Are there pre-existing sediment or water quality issues?
• Is a reservoir present with the system?
• What metals make up the turbine and are these metals treated to prevent corrosion?
• Water quality issues exist down stream from the hydropower turbine. This is because of the impoundment that may occur from a hydropower system. There are various problems that may occur from hydropower in a river such as: changes in oxygenation, temperature, stratification potential, pollutant inflow, propensity for disease proliferation, nutrient capture, algal bloom potential, and the release of toxins from pre-existing sentiment. 
• In addition to the previously mentioned issues, turbidity issues may occur in the body of water.  This can cause the water to reduce in quality due to stirring up sediment on the banks of the river. Also, the banks may erode more quickly due to this turbidity. 
• Corrosion of the turbine is a concern in terms of it impacting water quality. Corrosion of metals in general has a lot of variety. A main factor of this is the material of which the corrodible surface is made out of. Different metals have different corrodibilities. 
• More corrosive factors:
• Low hardness
• Low alkalinity (<50mg/L of calcium carbonate)
• Water quality can impact the agriculture of an area as well. If the water is high in certain minerals, the livelihood of plants may be negatively impacted. The three most important nutrients to plants are potassium, nitrogen, and phosphorous, so any water quality issues that may impact those nutrients would be a problem.
• Social Impact
• Conducted preliminary research on hydropower technology in general in preparation for the first essay due February 20. Found that hydropower is one of the most important renewables for electric power production. In fact, it provides about 20% of the earth’s electricity. In micro-hydropower, there is usually no dam or water storage and therefore is extremely cost-effective and environmentally sound energy resources.
• The technology aspect of micro-hydropower in general can be summarized as such: a turbine converts the potential energy from falling water to a usable form of electricity. Each turbine is different, and they all have a specific power characteristic that depends on speed of water flow. It is important to have a consistent flow of water in order to produce consistent power. Therefore, one consideration that the environmental impact assessment team that I am also on is going to explore is how to compromise for any reduced flow conditions as Bangang is in a semi-arid region of Cameroon.  
• The team will more thoroughly and eloquently delineate the positives and negatives of micro-hydropower.
• Made minimal changes to the IRB narrative
• Added sources to the bibliography
• Helped the environmental team design a work plan similar to that of the SIA team.
• Networked with a visiting anthropologist who works on dam issues
• Economic
• NA
• Construction Management
• NA

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

2/3 Weekly Brief

Design

• Hydrology
• Researching current trash rack systems that are feasible considering locations and materials available
• Assessed feasibility of designing silt basin
• For next week, need to determine geological composition of the area
• Contacting creator of watershed delineation from 2010
• Geotechnical
• Researched information: the current system in place to deliver electricity from the hydraulic turbine consists of aluminum conductors hung from Eucalyptus poles. The base of the poles are treated and set in the ground, held in place by large volcanic rocks and back filled with soil.
• Important factors to consider are the declining availability of Eucalyptus in the area and the relative density of the soils used to secure the poles. The relative density controls the mechanical properties of the soil and thus highly influences the effectiveness of the pole foundations.
• Questions to consider:
• What is the relative density of the volcanic rocks used and the soil?
• Are all the poles spaced out evenly? (or) What is the average spacing of the poles?
• Is any material other than Eucalyptus available or used at all?
• How heavy are the wires/aluminum conductors (per ft or m)?
• How large are the rocks at the base of the poles?
• Where can more information about landslides be found?
• What is the total distance that the lines will be carried for?
• What tools are available?
• What is the void ratio and porosity of the soil?
• What is the average rainfall per month?
• Who owns the property where the lines will be run through? How do the owners feel about it?
• Mechanical
• Reached two sources to get recommendations on how to design the desired Electronic Load Controller (ELC): Professor Galen King from the Mechanical Engineering department and Zhu Xiongfeng, a former teaching assistant for ME 475 (Automatic Control Systems)
• The recommended feedback control is the proportional-integral-derivative controller (PID); this type of controller involves tree constant parameters that are associated with the error between the reference signal and the measured value. These parameters will regulate the present errors, the accumulated past errors, and the predicted future errors. The weighted sum of these errors is then converted in a command sent to the control element.
• The angle of the teardrop regulator will be controlled through stepper motor, dc motor, or a hydraulic mechanism
• Modern Control Engineering by Katsuiko Ogata will be used as the guide in designing the team desired feedback control.
• Objectives for next week include developing a better understanding of PID controller and beginning to write the code for PID controller
• Completed conversion of all 3D parts from the 2013 prototype to 2D orthographic drawings with annotated dimensions
• Separated runner assembly manual into the following sub-assemblies
• Runner
• Cover
• Turbine
• Questions to consider:
• What is the standard utility frequency in the village of Bangang?
• What is expected from a data acquisition system, automatic voltage regulator, and electronic load controller?
• Power distribution
• Developing order of tasks needed to be done
• Identifying information needed to calculate energy demand
• Identifying ways to reduce energy losses
• Identifying ways to improve distribution map

Assessment

• Environmental Impact
• Questions to consider:
• Are there any examples of the most appropriate EIAs?
• Are there any EIA resources from years past?
• What is the name of the body of water upon which our project is based? Is it fresh water or salt water?
• Approximately how many people get their water from the river system that feeds our turbine?
• Is it used for fishing or just obtaining water or is it used at all?
• Social Impact
• NA
• Economic
• NA
• Construction Management
• NA

1/27 Weekly Brief

Design

• Hydrology
• Reviewed the following issues with regards to the hydropower civil works:
• Streamflow data (daily or monthly)
• Efficiency of the current system (primarily concerning the volume of water)
• Summary of the current infrastructure
• Geographic information about the site
• Identifying relevant information and sources
• Slope of penstock
• Soils information
• Manning coefficients of local materials
• Geotechnical
• Reviewed geological records and semester objectives
• Discovered the following: The variance of soil type, topography, and vegetation in Cameroon make a thorough preliminary study of the geology specific to site construction an essential factor in the design concept. Located in the western region of Cameroon, the soils in Bangang are predominantly Ferralsols and Nitosols containing high levels of volcanic ash. Erosion due to rain has a high impact in this region, largely due to the slope of many cultivated areas. Existing geological information suggests that, despite the rain erosion experienced by the western region of Cameroon, the soil has few chemical constraints by the western region of Cameroon, the soil has few chemical constraints because of high organic matter content and the volume of volcanic ash in the soil. 
• Mechanical
• Started converting 3D inventor part drawings to 2D orthographic drawings with dimensions for use in assembly manual
• Outlined a rough assembly guide based on the trip report
• Read up on a number of economic journals
• Review the functions of all the hydropower turbine parts
• Compared different hydropower turbine design models (Francis, pelton, kaplan, and crossflow). The so-called "Purdue 2" turbine is a crossflow turbine
• Reviewed the 2013 Cameroon trip report
• Questions include:
• What is the total head?
• What is the design flow rate?
• What is the length of penstock used?
• Do we have a method for controlling the power output?
• Does the village want the turbine to run on maximum capacity throughout the season? The pelton turbine uses a spear valve to control shutting and running the design so perhaps we can control the power output in a similar process.
• Power distribution
• Reviewing semester objectives and organizing tasks
• Determining what information is needed for the design of the system
• Reading Mini Grid Design Manual with regards to electricity usage, lighting, and costs
• Prepared list of questions that need answering about the grid design in use and what needs to be improved upon
• Other information needed includes:
• Electricity usage
• Typical use of electricity per household
• Expected growth in consumption
• What is the major area of use of the electricity? (re: lighting, machiner, etc) If lighting, what kinds of bulbs are they using? How many bulbs per plot? Who is providing the bulbs/lighting?
• Judging by the map of the village and the power lines along it, we estimate that nearly half of the village (the houses, stores, and bars along the road) are supplied with electricity. Residential sectors not near the road are not. The data here which is needed is:
• For the past five years, what has the consumption of electricity been like?
• Which is the principle user of electricity (residents, stores, or bars, etc) and what is our "target" community size?
• What is the electricity that has been supplied so far for the past five years? (numbers for each year preferable) This will be used to create a supply demand comparison to understand our needs.
• What kind of grid do they use/have?

Assessment

• Environmental Impact
• Read one of the case studies
• Discovered and considered the following: the air quality is not well measured in Cameroon. However, there is a volcano in Southwest Cameroon as well as an oil refinery nearby that could already contribute to air problems. We need to figure out how clean the energy is that will be emitted from our hydropower system. Also, we've been looking through the team documents to see what kinds of materials that go into the turbine, so that poses the question at how they're altered by the elements and how that affects the water quality. About how many people use the water source that we are using for our hydropower system? We're looking to supply power to about 1000 homes, but maybe more would be affected by any water quality changes? We haven't had the chance to look at all of the documents yet, so maybe some of this information is stuff we already have, but it's just things to think about. 
• Social Impact
• Reading though some sample social impact evaluations of similar projects
• Begun to read chapter 7 of Micro Hydroelectric Power Stations by L. Munition, M. Le Nir, J. Roux to become more familiar with the kinds of factors to look at when we are assessing the environmental impact.
• Economic
• Construction Management

Spring 2014 Semester Objectives

The team is off to a very productive start this year with the identification of eight primary sub-teams or "focus groups". Each team consists of one to three students (both graduate and undergraduate) and will work to fulfill a very specific list of design objectives as derived from various books, journals, articles, and discussions with experts on the Purdue campus.

The focus groups this year can be broken up into two larger categories: design and assessment. The full project breakdown and objectives are as follows:

• Design
• Hydrology civil works design
• Primary design objectives: weir, conveyance channel, headrace channel, guiding walls, silt basin, forebay tank, intake screen, spillway, aqueduct, weir, penstock, coarse settling basin, diversion channels or gutters, tailrace channel
• Primary reference text(s): Designing and Building Mini and Micro Hydro Power Schemes: A Practical Guide by Luis Rodriguez et al
• Geotechnical civil works design
• Primary design objectives: investigations and site characterization including assessment of ground conditions, assessment of effect on construction, assessment of foundation construction process, quality control and monitoring. Objectives also include design of foundations, planning for construction, and foresight into system control and monitoring
• Primary reference text(s): General Principles of Foundation Engineering by Purdue Geotech Professor P.L. Bourdeau
• Power distribution system design
• Primary design objectives: powerhouse, map of area to be served, determination of line configuration required to serve expected load, design of conductor, established minimum line-to-ground clearance, assessment of pole options that are available and that satisfies clearance and strength requirements, select poletop hardware, design of pole guys and anchors where required, determination of adequate safety and protection for housewiring configuration based on level of services to be used by each consumer, determination of metering consistent with desired load profile, selection of conductor type and size for service drop
• Primary text: Mini Grid Design Manual by Allen Inversin
• Construction engineering management and optimization
• Primary objectives: resource leveling, program evaluation and review techniques (PERT), work breakdown structure, project cashflow, construction safe, activity precedence diagram
• Primary text(s): TBD
• Assessment
• Social impact assessment (SIA)
• Primary assessment objectives: logical framework, conflict and impact assessment, identificatoin of critical success factors (CSF), semi-structured interviews, system monitoring and evaluation, information needs, identification of biases, mandate and mission statement, stakeholder analysis, objective statement, rapid assessment strategy and report, branching tree analysis, community study, force-field analysis, surveys, evaluating strategy options, project sustainability assessment, access structure, system matrix, marketing matrix
• Primary text(s): Social Impact Evaluation Project 'Fund for the Promotion of Micro Hydro Power Stations (MHSP)' by Julio C. Cockburn and Shortcut Methods of Gathering Social Information for Rural Development Projects by Robert Chambers
• Environmental impact assessment (EIA)
• Primary assessment objectives: noise impact, visual impact, biological impact (including botanical, wildlife, rare/threatened/endangered species), water impact (including quality and quantity), and geological impact
• Primary text(s): AES-SONEL Investment Program Cameroon, West Africa: Executive Summary of the Environmental and Social Impact Assessment by AES-SONEL and Small Hydropower Plant - Environmental Impact Assessment - Case Study by Zelenakova et al
• Turbo-mechanical assessment
• Primary assessment objectives: data acquisition system, control systems, more TBA
• Primary text(s): TBA
• Economic evaluation
• Primary assessment objectives: cost of installation, income generation, unit energy cost, net income, net present value, cost-benefit analysis, financing options and recommendations, capital investment and profitability, financial cash flow, annual running cost, profitability criteria, capability and demand survey, feasibility report, and conditions for use of the power plant
• Primary text(s): TBA

As many of these project components already exist at ACREST, most of our work this semester will focus on refurbishment and rehabilitation of current infrastructure, with explicit recommendations for future expansion and modification of the major civil works.

Updates will be provided weekly.