ENGR 270/470

Design and Efficiency

Evaluation of Solar Kits

Daniel Alvarez, Charles Arnold, Leah Murff, Brandon Tran & Sponsor Dr. Seydou

[11/29/2016]

Team Name: Sustainable Energy for Education (SEE)

Team Members

Brandon Tran - Junior Industrial Engineering

Daniel Alvarez - Sophomore Electrical Engineering

Leah Murff - Junior Electrical Engineering

Charles Arnold - Sophomore Mechanical Engineering

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[Table of Contents] Project Need & Design Requirements …….................................................................................3 Sponsor Background ……............................................................................................................4 Design Concept Generation & Evaluation …….........................................................................6 Baseline Design .……...................................................................................................................17 Work Breakdown Structure ……..............................................................................................22 Educational Outcomes …….......................................................................................................24 Impact and Future Work …….................................................................................................25 Acceptance Documentation………………………………………………………………….....26 References……………………………………………………………………………………….27

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1. Project Need & Design Requirements

1.1 Project Scope

Rural communities in Burkina Faso, Africa, do not have electricity and lights. As a result, the residents are limited to only doing their work during the day. Our project will focus on children who need to study at night and classrooms that do not have sufficient lighting. The Community building Group - West Africa, attempted to solve this issue by creating simple off-the-grid solar panel kits that could be attached to houses and schools. The solar kits power two LED light bulbs outside the resident’s homes and inside classrooms as a source of light for children to do homework at night. Currently, the solar kits are not utilized efficiently and could be wasting energy, thus not reaching their maximum potential.

The solar kits will be evaluated on their efficiency and redesigned so that they can provide light more efficiently. The desired deliverable for the project is a solar kit that is as efficient as possible given the constraints, can power 4-7W LED lights for 6 hours, and is durable for outdoor use.

This project would allow students and community members to get work done and socialize after dark. Community members have said that over 15 students will be using two lights at a time, and that community members also use these LEDs as social gathering points after dark. Creating more efficient solar kits with more lights will give students a space to study, give community members an area to socialize and work, and allow schools to have more light inside of classrooms.

1.2 Project Objectives

Long term objective:

a. Incorporating a timer to the system so that the lights can automatically turn on and off from 6 p.m. to 12 a.m.

b. Solar mounting system that can be moved to 3 different angles to optimize energy collection.

c. Present the project at an Enactus Competition. d. Reach GoFundMe goal of at least $515 to donate to the project. e. Work on outreach and expanding this idea to as many rural areas as possible.

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One semester objective:

a. A solar sizing chart of different solar sizes. b. An improved solar kit that meets the project objectives and design requirements. c. Create a dimensional sketch in SolidWorks of a multipurpose shelter with four lights

sustained by solar energy. d. Increase the total amount of lumens by 50% for original set up. e. Keep cost under $200.

1.3 Design Requirements and Constraints

● Design Requirements i. Solar sizing chart must contain at least 10 different options.

ii. Increase amount of lumens by 50% for original set up. iii. Keep cost less than $200. iv. The lights need to run from 6p.m. - 12a.m. (6 hours).

● Design Enhancements i. A solar panel that can be moved three times a year to receive more direct sun

light. ii. Timer for lights to automatically go off at 12 a.m.

iii. 1 extra light bulb for the interior of the building

2. Sponsor Background

Dr. Seydou Traore is the executive director of the non-profit corporation Community

Building Group. The purpose of the CBG is to develop sustainable communities and improve lives of those living in rural areas of Burkina Faso with focus on water and renewable energy. Since Burkina Faso is a landlocked country with no access to water, many citizens living in the country experience a lack of water. One project of the Community Building Group-West Africa was the Give Water Give Life project which implemented a rainwater collection basin so locals could use this water to irrigate farms, raise livestock, and improve daily lives. The other project that the CBG-West Africa worked on was the solar kits for schools. What this project entailed was providing light at night time in small rural villages in Burkina Faso. A self sustainable solar kit included lights and batteries and ran at night time to give kids an opportunity to study and do work after the sun had set. With this, those going to school could improve their studies and in turn help their families. By giving children access to light after dark, the CGB-West Africa has improved not only the lives of children in Burkina Faso but their families as well.

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Villagers and children surround the new solar kit equipment to be used in schools.

The geography of the rural villages in Burkina Faso makes it difficult to have sources of electricity for infrastructure. Obtaining a way to have sustainable off-the-grid power has helped many of these villages since it is hard to perform tasks in darkness. What the CBG has done is lengthen the amount of time schools can operate at (since schools use sunlight for their classrooms). The purpose of the project was not only to install light to schools, but to aid the locals in learning how to use and upkeep the solar equipment for the long term. With the success of this project and the impact it has left on the community, this project could be expanded to surrounding villages and homes where multiple families could make use of the solar kits.

Currently the kits are complete with 2 lights powered by a solar panel. These kits (shown to the right) are installed on the side of residential buildings and give light to children working on homework at night. The impact of these kits has brought villages closer and freed time for locals to work on other daily tasks. With the CBG, Dr. Traore has changed and improved the lives of many local peoples in Burkina Faso, and with the help of this task force there can be even more improvements for the solar kit system

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3. Design Concept Generation & Evaluation

3.1 Background Research This example from Heriot Watt University had a design to be implemented for multiple rooms of a building, but the prototype was for one room and quite similar to the solar kit already in use in Burkina Faso.

The article also had calculations that will be useful for our team while we optimize the solar kit. This example from the University of California was made for customers in zambia also has a similar design to the solar kit in Burkina Faso.

The report had several charts containing data that will be useful in our project. This example from Quetsol, a renewable energy company, which has a product similar to the solar kit to run lightbulbs.

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we can compare our solar kit to their solar kit to check efficiency

3.2 Functional Decomposition ● Function 1: Collecting Energy- Design must maximize the solar energy being received

by the panel while still being cost effective. ○ Angle of solar panel ○ Type of solar panel ○ Size of Solar Panel

● Function 2: Storing Energy- Design must be able to store energy in a battery without overcharging or allowing energy back into the panel through controller/regulator.

○ Deep Cycle Lead Acid Battery ○ Lithium Ion Battery

● Function 3: Lighting- Design must increase total light output in lumens by 50%. The type and size or lights must be optimized.

○ Increasing Luminous Intensity ○ Type and number of lights

● Function 4: System Design- The system (beside the walls of buildings or the shelter) must be structured through a human-centered approach while maintaining proper sizing.

○ Illuminance ○ Human-centered design

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With these four functions defined, the diagram shown below visually represents the relationships among the different functions.

3.3 Design Concept Generation

Function / Design Concept

Function 1 Collecting

Energy

Function 2 Storing Energy

Function 3 Lighting

Function 4

System Design

1st Design Concept Description

Cost Effective:

1 tilt angle polycrystalline solar panel

Deep cycle lead acid battery

Increasing luminous intensity from light source

Illuminance

2nd Design Concept Description

Most Efficient:

3 angle tilt monocrystalline solar panel

Lithium ion battery

Type and number of lights

Human-centered design

Team Member Name in Charge of Each Function

Charlie Arnold Leah Murff Brandon Tran Daniel Alvarez

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● Function 1: Solar Panel Angle ■ The angle of the solar panel is based off of the angle in degrees from

level when the solar panel is facing true south. The angle will also differ based on the latitude where you are placing the solar panel. Burkina Faso’s latitude is 12.238 Degress North. The calculations for the different design options were taken from http://solarpaneltilt.com/#fixed. This sight used over 12,000 data points and was written by Charles R. Landau, who is a senior software engineer currently at Arxan Industries. The full link is in the references page.

○ Design 1: Fixed Angle ■ For a fixed year round design, it should be angled at 10.65 degrees. ■ Benefits: Least amount of Maintenance, lowest cost of mount, and

simplest design. ■ Drawbacks: 72% from optimum angle.

○ Design 2: 2 Angles ■ the 2 angles will each cover half of the year. The Winter angle will be

30.1 degrees and the Summer angle will be -9.2 degrees. ■ Benefits: 76% of optimum angle, 4% more than design 1. Lower

maintenance than design 3. ■ Drawbacks: Mount just as costly as design 3, requires more maintenance

than design 1. ○ Design 3: 3 Angles

■ The 3 angles will cover all four seasons. The angles are 10.25 degrees for Spring/Fall, -12.8 degrees for Summer, and 35.3 degrees for Winter.

■ Benefits: 80% of optimum angle, the best of all 3, meaning it will receive more direct light.

■ Drawbacks: Costly mount, requires most time for maintenance, most complex design.

● Function 1: Solar Panel Type ■ Information of the various types of solar panels with their benefits and

drawbacks was determined from Energyinformation.org , a link is in references.

○ Design 1: Monocrystalline ■ Benefits: More efficient, less space, and longer lasting. ■ Drawbacks: Expensive, less coverage resistant, and more waste in

production ○ Design 2: Polycrystalline

■ Benefits: Less waste in production, cost less. ■ Drawbacks: Less efficient, less space efficient, and less aesthetically

pleasing ○ Design 3: Thin Film

■ Benefits: Lower cost, can be made flexible ■ Drawbacks: Less space efficient, very space inefficient(4x less)

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● Function 1: Solar Panel Size ○ The size of the solar panel will be independent of the angle and type of solar

panel, but it is dependent on the type of battery and load that it needs to supply energy for. This means that instead of multiple designs to decide over, the size of the solar panel will be determined using equations that have variables for the battery efficiency, load, and time load is needed. These equations are found by converting all parts of the solar kit into amps and then using the relationship amps in = amps out and Amp=W/V.

anel Size (W ) 2(V )P = (Total Load (amp hr)*(Eff iciency of Battery)(Hours of Solar Energy per Day(hr)) * 1

○ The Total load is calculated by multiplying the load by the time it is needed. For example, if you needed to power 4, 7 W bulbs for 6 hrs. You would first convert 7W to amps by dividing by 12 V since that is the voltage the system is running at. Then multiply that by 4 for the amount of bulbs and by 6 hrs for the total time. The total load would then be 14 amp*hrs.

○ The efficiency of the battery is determined by the type of battery. Lead-acid batteries are usually 80% efficient, and lithium-ion batteries are usually around 90% efficient.

○ The hours of solar energy per day is the average amount of time the solar panel will produce energy at its rated wattage per day. This can be considered a constant for a certain region. Based on field tests and solar insolation maps, it was determined that Burkina Faso receives 3.75 hrs of solar energy per day.

○ Finally all of it is multiplied by 12 V to get the size of the panel in Watts which is what sizes are commonly measured in.

● Function 2-storing energy: Lead Acid batteries

Deep cycle lead acid batteries are commonly used in solar energy projects.The current solar kits in Burkina Faso use this type of battery and there is a technician that is very familiar with this battery. The current battery in use is also cheaper than typical lead acid batteries and should last longer.

● Function 2-storing energy: Lithium Ion batteries

lithium ion batteries are at more efficient than lead acid batteries and last much longer. Lithium ion batteries cost more than lead acid batteries but the longer lifecycle should make up for the initial cost. However with a limited budget the increased cost may not be acceptable Availability in Burkina Faso is limited.

● Function 3-Lighting: Increasing Luminous Intensity Luminous intensity is the light energy that is emitted by light in a particular direction.

The current product wastes much of the light energy to the surroundings as the light spreads like a sphere. Increasing the Luminous intensity to focus the light onto the student’s papers would vastly improve the current design by brightening the workspace. At best, luminous intensity can be increased by 4π (12.6) times the present intensity if there were reflectors all around the light

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bulb. To do this, a parabolic reflector is placed around the bulb. Shown below are some schematics of how this function would be implemented.

The first image on the left shows the current product, light goes in all directions hitting the wall of the building and going off into the dark night sky. In the second image, a reflector is placed around the the bulb so light energy can be directed in one direction.

● Function 3-Lighting: Increasing number of lights To increase the amount of light even further, the type and number of lights could be

assessed. Currently the kit uses two 6 Watt LED bulbs. LED bulbs are cheaper, more efficient, and last longer than other alternatives (incandescent or CFL)given the lifetime of each bulb. The 6 Watt LED bulbs(outputs 450 lumens) are also harder to find than 5 Watt/7 Watt bulbs. It is determined that the 7 Watt LED bulbs which output 680 lumens would be optimal. Furthermore given the current battery and solar panel, the number of light bulbs can be increased from 2 bulbs to 4 bulbs, doubling the amount of lights in the system.

● Function 4-System Design: Illuminance Illuminance is the measure of how much light strikes the surface of an object. Good

illumination of the workplace is a critical part of the system so that fine detailed work such as reading and writing can be done. To increase illuminance, either the distance from the light to the workplace can be reduced, or the luminous intensity increased. Distance from the light to workplace is inversely proportional to illuminance while luminous intensity is directly proportional to illuminance. Once the illuminance is of the workplace is measured, it can be compared to OSHA standards. The OSHA standards dictate minimum and prefered illuminance of a workplace so that productivity can be maximized. Shown below in the table is the minimum illumination level of different degrees of work.

Activity Illumination (lux)

Public areas with dark surrounding 20-50

Simple tasks 50-100

working areas where visual tasks are occasionally performed

100-150

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Warehouses and homes 150

Easy office work, class 250

normal office work, groceries, laboratories 500

● Function 4-System Design: Human-centered design

Using a human-centered design approach, the two systems can be studied. The first existing system with two lights on the walls of buildings give minimal lighting in an enclosed space. While there are typically around 18 kids using these lights, not all of the kids are able to utilize the light. The second system is the proposed shelter which will have four lights with a 5x5 meter area and 2 meter height. In determining the dimensions of the shelter, there must be enough area to accommodate the required 18 kids. A square shelter is better suited than a rectangular shape because of equal light distribution. This multipurpose shelter can hold more than 18 kids at a time and can be used for studying, meetings, or recreation. The figure for the design is in section 4 of the report.

● Function 4-Details: The minimum illuminance required for the kids to do work is assumed to be 250 lux.

Given the dimensions of the shelter to be 5x5x2 meters with each bulb having a rating of 680 lumens, the illuminance of the workplace can be determined. Illuminance is indirectly related to distance and directly related to luminous intensity. The equation is:

os(θ) E = I × c ÷ D2

where E is the illuminance in lux, I is the luminous intensity in candelas, θ is the angle between the light source and workplace, and D is the distance from the light source to the workplace. Each light bulb gives off about 680 lumens which can converted to 680 candelas if a parabolic mirror is used. The lights in the shelter are equally spaced in a square about 1.25 meters from the edges of the ceiling. From these values the illuminance in the center of the shelter would be about 262 lux, 12 more lux than the minimum.

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3.4 Design Concept Evaluation ● Function 1: Solar Panel Angle

○ This decision matrix compares a design concepts with 1 tilt angle, 2 tilt angles, and 3 tilt angles. The 4 factors considered when deciding the best design were the cost to build and operate, the efficiency of the angle, the reliability of the mount, and how easy it is to create a design. The winner came out to be the 1 fixed angle. This was the winner because it was the most cost effective, reliable, and easiest to design.

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● Function 1: Solar Panel Type: ○ This decision matrix compares the benefits and drawbacks of a monocrystalline,

polycrystalline, and thin film solar panel. These different types of panels were compared by their price, size, efficiency, and how much waste is created in production. The winner came out to be polycrystalline panels. The polycrystalline panels are the most cost effective panels. Being cost effective was the most important aspect because the solar panel takes up a majority of the costs.

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● Function 2-Storing energy:

Initially we chose lithium ion batteries because of their efficiency and longevity, but after talking to our sponsor we discovered that cost and availability had a larger role than we anticipated and upon reevaluation Lead Acid batteries were the winner.

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● Function 3:

● Function 4:

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4. Baseline Design ● System Overview

○ Solar Kit ■ The solar kit consist of a solar panel, regulator, battery, and lights. ■ The size of these parts are dependent upon each other, so the team created a

sizing and cost chart to find the correct size parts for multiple variations. ■ The team also designed a kit that would supply enough light for 18 children to do

school work with. This kit consist of: ● 60 W polycrystalline solar panel at a fixed angle ● 4, 7 W LED Lights ● 6 Amp regulator ● 35 Amp lead-acid battery

○ Shelter ■ The shelter is designed to fit 15-18 people who will primarily be doing work on

the ground. The shelter consist of a design that will have the solar kit encorporated into it.

● The shelter dimensions are 5m width x 5m length x 2 m height. ● The lights will be spaced 1.25 m from the edges. This will make the

luminance on the center of the floor just enough to be at reading level. This allows the center to be illuminated while also spreading the light as far out as possible.

● The solar panel can be placed anywhere, but it should be facing south and tilted with a 10.65 degree angle from level.

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Solar Kit Schematic

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Solar Shelter Schematic

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● Technical specs for all parts (manufactured or purchased) -Polycrystalline Solar Panel (60 Watts) - Lead Acid Battery (35 Amp-hour)

- LED light bulbs(7 Watts, 680 Lumens) - Controller (6 Amps)

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Solar Sizing and Cost Chart

● Cost Estimate ○ A cost estimate can be completed for various sizes of solar kits using the solar kit sizing

and pricing chart above. ○ The solar kit on the shelter will have:

■ 60 W solar panel = $90 ■ 4, 7 W LED bulbs = $28 ■ 6 Amp Regulator = $20 ■ 37.5 Amp Battery = $56 ■ Total = $194

○ The actual shelter is not included since the sponsor will have local villagers create the shelter before receiving the solar kit.

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● Design Requirement Comparison to Baseline design ○ Solar sizing chart must contain at least 10 different options.

■ The team created a solar sizing chart with 10 different sizing options and 9 cost options.

○ Increase amount of lumens by 50% for original set up. ■ Original setup had 960 total lumens. ■ Current setup has 2720 total lumens. ■ This is an increase of 183%

○ Keep cost less than $200. ■ Total cost is estimated at $194.

○ The lights need to run from 6p.m. - 12a.m. (6 hours). ■ The system is designed to run 4, 7W LED bulbs for 6 hours.

5. Work Breakdown Structure

Compare actual plan with proposed plan. How did the team use the 14 weeks of the semester to arrive at the current project outcomes? What were the main challenges and how were some of them taken care of?

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The main difference between the proposed plan and the actual plan was that the tasks often took longer than expected or the team had to push back the deadlines for completing tasks. Shifting the deadlines of tasks occurred for a few reasons. One reason was simply that the team member or team as a whole may have been working on other parts of the project or other schoolwork and the team did not have enough to complete that task on time. Another reason was that some tasks were dependent on other tasks, so if one task was completed late then others were completed late because they were counting on that first task. The final reason was that the team simply did not have enough understanding of the task and needed to wait on information from workers in Burkina Faso. The proposed plan also did not include weeks 1-6 since the proposed plan was only completed once the team had a more complete view of the task.

The main challenge was understanding the task and the team actually spent the entire semester

getting a better understanding of Burkina Faso, what the sponsor wanted, and how to create a solar shelter. The creative process for the solar shelter was definitely an iterative process where the team was constantly tweaking designs based on new information or better research. This is why the actual plan included understanding the need, because it was constantly happening and caused the team to go off schedule at some points. This issue was solved by working with the team’s sponsor and workers in Burkina Faso to get more information about the conditions that the solar kit and shelter would be in.

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6. Educational Outcomes With the inception of the team, the team members did not fully understand the scope of the

project while individual skills were not yet realized. At first the diversity of the team made it difficult to collaborate and work together, but with the help of Dr. Seydou each person’s skills and prior knowledge was put to use. The team worked together very efficiently, splitting up tasks and utilizing every resource available. Since the goal of the project kept changing, the team had to adapt and come up with many different designs which were presented to the Dr. Seydou every week. Making the right assumptions for the project drove the team in the right direction. What the team as a whole learned from the project included effective collaboration skills, time management, knowledge of solar lighting, and a drive to better people’s lives through engineering principles.

What each individual member learned from the project varied. Coming into the project nobody

knew how solar panels worked, but with research the team was able to understand and improve the solar kits. Charlie, Leah, and Daniel knew how to solder while Brandon was more equipped with programming. Since Charlie knew how to use SolidWorks and Leah knew how to design through autoCAD, formulating design models were key. From the size of the panel to the size of the battery, the team learned how to properly size a solar kit given the amount of lights needed. With Charlie’s knowledge of SolidWorks and Leah’s CAD design skills, they were both able to improve their 3-D design and printing. The human-centered design and lighting principles provided from Brandon gave the team information about focusing a system around humans and configuring lights through illumination and luminous intensity. Daniel’s research on energy consumption and solar lighting helped bring the whole project together. From Leah’s research of batteries, the team was able to understand the different types of batteries and the efficiencies of them. The weekly meetings with Dr. Seydou gave the team valuable information about the rural communities in Burkina Faso.

From not understanding the project goal to delivering an improved kit with a proposed shelter, the

team members were able to develop their engineering skills and increase their knowledge about solar energy. Sustainable off-the-grid energy is key in these parts of the world because the geography makes it difficult to run power lines to rural areas. Towards the end of the project the team members were participating more in group meetings and effectively achieved the goal by splitting up work and providing research. The values the team learned was that even though ignorance of a project can hinder progress, with enough dedication and teamwork the goal can be achieved.

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7. Impact and Future Work For our project we made a new solar kit that is more efficient than the current solar kit. With our

kit the community will get the most amount of light for the least cost which will give more kids the ability to do homework at night. Along with the sizing chart the sponsor will get the reasoning behind the numbers and these materials can be used as a proof of concept to request more funding for this project so more solar kits can be provided to rural communities in burkina faso.

Along with the new solar kit we came up with our system in which the solar kit will be used in

conjunction with a shelter so more kids can use the light and will not have to work on homework outside another person's’ house. Our sponsor was very pleased with the idea will actually use the shelter as a way to determine what communities will receive solar kits. The program our sponsor works for may now make it a requirement that the community build a shelter for the solar kit in order to receive a solar kit, this requirement will make deciding which communities get solar kits easier for the program. Because of our idea we have changed the course of a program that will affect many communities in Burkina Faso.

For our long term objectives, we have a few ideas in mind. A timer would be very beneficial to the system and the community since the system can run for a certain amount of time without any human interaction. Another solution would be increasing efficiency by changing the solar panel’s angle at least three times. We calculated that it would be 8% more efficient than having a stationary angle. This would allow for more energy to be stored by the solar panel, allowing the system to last a little longer.

We want to expand our ideas to many rural areas as possible. Our project has taken a step forward with the idea of having a shelter with a solar kit installed. We have done our research and calculations for the dimensions and materials of the shelter. Our results for the shelter may not be perfect, but we would like to improve it. The dimension of the shelter is based of the illuminance produced by the four LED’s. The size of the shelter has to take in about 18 people. So working on a more reliable and stable shelter that would support a decent solar kit would be the future goal.

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8. Acceptance Documentation

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9. References "Lighting Levels - Guidelines and Definitions." Lighting Levels . North Coast Lighting Outlet, 13 May

2005.

Web. 29 Nov. 2016.

"Recommended Light Levels." Light Levels (2012): 521-22. Www.noao.edu . Web. 29 Nov. 2016

Landau, Charles R. "Optimum Tilt of Solar Panels." Optimum Tilt of Solar Panels . N.p., 11 Nov. 2015.

Web.

29 Nov. 2016.

GmbH, Steca Elektronik. "Steca Solsum F." Steca Solsum F: 6.6F, 8.8F, 10.10F :: Steca Elektronik GmbH,

87700 Memmingen . Steca Electroniks, n.d. Web. 29 Nov. 2016.

Maehlum, Mathia Aarre. "Which Solar Panel Type Is Best?" Energy Informative . N.p., 20 May 2015.

Web.

29 Nov. 2016.

Pon, Bryan. Designing Affordable Solar Lighting . Diss. U of California, Santa Barbara, 1999. N.p.: n.p.,

n.d.

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F, Michele. "Quetsol-Turn." Indiegogo . Quetsol, 10 Apr. 2013. Web. 29 Nov. 2016.

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