Background
Many schools, health centers, and other medical or humanitarian operations need better lighting, batteries, and device chargers that are portable and reliable. Since 2011, the nonprofit We Care Solar has worked with NGOs and development organizations around the world to help install Solar Suitcases in places where they are most needed.
The Solar Suitcase is a portable power unit with multiple functions. Standard kits are equipped with either two plastic-backed 20-watt solar panels or one 50-200 watt aluminum glass solar panel. They come with a 12 volt LFP battery, two LED lights, two rechargeable headlamps, USB slots, a AA/AAA battery charger and roof/wall mounting kits.
Problem statement
The objective for this project is for our team to construct a portable photovoltaic system or 'Solar Suitcase' and design a lab for our engineering class where we will teach about Photovoltaics and how to construct our portable Pv-cell suitcase. We also seek to revamp the design to potentially find ways to make it more intuitive or helpful to the users. We will be constructing the Solar Suitcase using materials provided to us by the HSU Engineering department and the Schatz Energy Research Lab.
Project Evaluation Criteria
The following criteria will be used to assess the success of this project. These criteria were chosen by our team to aid our goal of teaching the rest of the class about the Solar Suitcase. The scale (1-10) represents the importance level of meeting the constraint of each listed criteria.
| Criteria | Constraints | Weight (1-10) |
|---|---|---|
| Assembly | Students must be able to assemble and test the Solar Suitcase during the allotted lab time. | |
| Concepts | Students must achieve an understanding of the function of each component and how the components fit into the entire system. | |
| Purpose | Students must be aware of the overarching purpose of the Solar Suitcase Projects. | |
| Functionality | Each Solar Suitcase must be completed and operational. |
Literature Review
This is a review of the available literature pertinent to the HSU Solar Suitcase Project.
Photovoltaic (PV) systems
Radiant Solar Energy
The sun is constantly emitting electromagnetic energy that earth is bombarded with. The amount of sunlight reaching any given area on earth is called insolation (watts/meter sq.). Insolation is a function the distance from the sun to earth (on average 93,000,000 miles), the time of year (how the earth is tilting on the axis), time of day, climate, and shading. The climate and atmosphere at any given moment highly affects the amount of solar insolation, as dust particles or humidity affects solar radiation reaching the surface. Insolation data for various world regions are available c from both governments and other organizations. The amount of energy that actually reaches your load is highly dependent on the solar insolation.[1]
Components
Solar panels- Flat devices placed in the sunlight to harvest solar energy. Made up of photovoltaic (PV) cells and able to convert sunlight into usable direct current (DC) electricity. Electricity output is dependent on the angle at which the solar panel is placed in relation to the sun. For example, a panel placed at a 90 degree angle to the sun is getting the most direct sunlight.[2]
Inverter/Transverter - converts low voltage DC electricity into main voltage Alternating Current (AC) and from here the electricity is available to be used.[3]
Voltage Regulator/Charge Controller - device for managing voltage from solar panel to battery by providing the battery with the optimal current and keeps it from overcharging.[3]
Battery- stores electricity for later use. Lead-acid batteries are often used but nickel-cadmium batteries are common as well.[3]
Light Bulb - lighting is the main use of electricity in small solar systems and choosing an efficient bulb ensures the PV system can power the light.[3]
Wiring Basics
Most PV modules are produced as 12-volt modules, and in order to reach the system voltage, series wiring and parallel wiring of batteries is required. The diagrams, sizing charts and other useful information can be found in the book referenced in this section.[4]
Decentralized Solar Development
Solar energy systems can conveniently be located off the grid, which is perfect for the developing world. Off-grid small scale solar home systems(SHSs) are cost effective ways to respond to energy poverty challenges. SHSs allow rural communities around the world to gain energy without relying on expensive fossil fuels, like kerosene, or attempting to extend national electricity grids, which comes with a high price tag. While SHS programs greatly enhance quality of life in the developing world, the high upfront cost of these systems tends to only allow middle and upper class rural homes to have access and the systems are prone to theft and damage. However while they are expensive and hard to come by, there are more than 40 SHS programs around the world that are committed to installing these systems in efforts to curb energy poverty through off-grid electrification.[5][6]
References
- ↑ Bullock, Charles E. (1934). Making the Sun Work For You. New York, NY: Can Nostrand Reinhold Company. 40-57
- ↑ Kreider, J., & Kreith, F. (1982). Solar heating and cooling: Active and passive design (2nd ed.). Washington : New York: Hemisphere Pub. ; McGraw-Hill, 7-152.
- ↑ 3.0 3.1 3.2 3.3 Roberts, S. (1991). Solar electricity: A practical guide to designing and installing small photovoltaic systems. Englewood Cliffs, N.J.: Prentice Hall, 37-133.
- ↑ Schaeffer, J., & Pratt, D. (2001). Solar Living Sourcebook: The complete guide to renewable energy technologies and sustainable living (11th ed., Real Goods solar living book). Ukiah, CA : White River Junction, Vt.: Gaiam Real Goods ; Distributed by Chelsea Green Pub, pg 478.
- ↑ Karoly, R., Iorga, N., Dorin, B., & Cristian, D. (2014). Energy Monitoring and Load Control. Application for an Off-Grid PV System. Scientific Bulletin of the Petru Maior" University of Tîrgu Mureș, 11, 30-33. Retrieved February 16, 2018.
- ↑ Sovacool, Benjamin K., and Drupady, Ira Martina. 2012. Energy Access, Poverty, and Development : The Governance of Small-Scale Renewable Energy in Developing Asia. Abingdon: Taylor and Francis. Accessed February 14, 2018. ProQuest Ebook Central. https://ebookcentral.proquest.com/lib/humboldt/reader.action?docID=1068875&query=