23-09-2016, 03:56 PM
1455942602-EnergyharvestingfrommultiplesourcesforBatterycharging.rtf (Size: 846.13 KB / Downloads: 6)
Abstract
This Project is an attempt for improving the communication in rural areas by developing an off-grid portable cellphone backup charger which uses various forms of renewable energy.
The various forms of energy used in this project are solar, wind and heat due to their availability and cleanliness. With the advancements in power, now it is able to harvest energy from sources which are impossible to harvest using traditional energy conversion methods. In this project, a proposed converter for the cell-phone charger was designed, constructed, and then tested. Results show the functionality of the proposed converter to charge Cell-phones. Further improvement of design will also be described.
. Introduction:
Cell-phones and laptops are becoming an integral part of our social life. For everything from playing games to cooking food, sending sms messages to attending business conferences, watching movies to doing banking, we depend on our cell phones. Cell-phones and laptops are to becoming a must moving from being a luxury. According to “The Guardian” there are 4.1 billion users of cell phones in the world, which is 60% of the world’s population, proving cell phones are becoming the most important personal communication device [1]. Just like how the cell phone is becoming an important need, it is equally important to be able to power up cell phones. According to the International Energy Agency, in 2011, 1.4 billion people around the world did not have access to electricity [2]. There is a huge portion of world population who cannot use a cell phone due to the lack of electricity. Also during natural disasters, like tsunamis or earthquakes, power outages will happen for days. During these power outages, communication is very essential, but the main communication device, cell phones, will be useless due to the lack of power.
This senior project is developing a cell phone charger that uses multiple renewable sources of energy to provide uninterrupted power for cell phones. With further investigation, the most convenient sources that could be used in this project are solar, wind and thermal sources. During the day time, the cell phone charger could use solar energy from the sun. During night time, the cell phone charger could use the heat from fire, or even excess radiating heat from cooking stoves or heaters. The wind source can be used when the consumer is travelling such as by boat. By integrating three different sources, this cell phone charger will be
able to provide power to a cell phone in three different diverse conditions
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2. Design Requirements
A. Project Goals:
The project goal is to design a portable cell phone power backup/charging unit that uses three renewable sources of energy, and can be used in rural areas or disaster affected areas without electricity from the grid.
Charger Specifications:
Below is a list of project specifications.
• Should be able charge cell phone without using electricity from the grid
• should be portable
• Should use renewable, readily available energy
• Should be safe to use
• Weather proof
• Affordable in third world countries
Solution Statement
As a requirement, in the project, three renewable sources of energy is included - solar, wind and heat as power sources. The main advantage of having these three as sources is that it is readily available, free of cost and little maintenance. After considering various options and components of design, the design shown in figure 2.1 is selected to implement.
Input
As per the requirement to use three renewable sources, the sources selected were solar, thermal and wind, since they are most readily available. For converting solar power to electrical power, solar panels were used. For converting wind power to electrical power, DC brushless generators are used. For the conversion of heat to electrical energy, peltier cells are used in this project.
Since there are three sources are present in the project, three DC-DC converters are needed to implement this project. For solar input source, a less expensive DC-DC converter is used because of solar panels relatively stable and high current supply. For wind and thermal inputs more expensive DC-DC converter like Ultralow Voltage Step-Up Converter and Power Manager (LT3108)
For Petlier cells, to keep a constant temperature difference a sealed oil (which stores
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heat energy even though the source of energy is removed) container on one side keep it hot and heat sink on other side to make it cool. It is achieved due to the property of oil to restrain the heat provided to it.
Output
Due to the variable availability of solar, low power supply wind and heat power, it is convenient to store the energy into a battery pack and then charge the cell phones from that battery pack. Having a battery pack will also provide an extra layer of back up during emergencies.
3. Design
A. Input
As per the requirement input sources of this project has to be renewable, available in rural areas and cheap. So three renewable energy sources: Solar for day time, Thermal for night time, and wind during traveling time is used in this project
Solar Cells
The main considerations given in picking solar cells in this project is durability, strength, output power and customer safety. Considering those as requirements and price, Solmaxx 2V solar panels are selected.
The advantages of this solar panel module is that it is weather proof, strong, tempered glass protected(If it breaks, it will shatter without leaving sharp edges so safe for the customers) and thermal electric insulated coating on rear side. The electrical properties of the solar panel is shown in table 1