Halversen, Justin
Triggering the Solar Revolution
Faculty Mentor: John Salmon, Mechanical Engineering
The sun’s energy emissions are significantly higher than other alternative energy sources. All other energy sources combined would not provide even one percent of the potential collectible energy from the sun. The amount of potential solar power available is well over 5000 times the current world consumption. Indeed, there is a very large and renewable reservoir of untapped potential solar energy which could be made more directly available to more people.
We explored several critical characteristics of solar energy from a cost-benefits perspective to determine if solar energy is a feasible strategy in order to help support the need for increased energy. Potential solar power generation was assessed across various assumptions and conditions to quantify the amount of electricity that could be generated while cost is analyzed by examining the trends and future expectations of solar cell costs over time. Then, specific “cost vs. savings” test case scenarios in public locations were conducted in order to determine the “break even” point for an investment in publicly available solar cells.
After purchasing solar cells, and building a solar table (see figure 1), experimental tests were performed to validate the potential energy that could be extracted from inside a public building and beside a window. The design process commenced with preliminary tests with solar cells exploring a small 3/4-inch square solar cell in series with 15 different resistors. After measuring the current and voltage output from the cell, we gathered sets of data from both shaded and sun-lit parts of the table at different times. This data enabled comparisons of voltage vs current at different resistive loads to calculate the maximum instantaneous power of the cells in their respective locations. The solar cells produced a lot less power in the shaded regions. These values were then applied to the dimensions and proportions of the solar table that would be exposed to direct sun and in the shade throughout the day.
The next step was to determine the cost vs. energy savings over time to determine how long it would take to pay off the cells. The total estimated cost of one solar table was around $200 with an assumption of BYU paying about $0.05 per kWh of electricity. Utah, on average, has a full sun charging time of 5.3 hrs/day throughout the year. If the cells provided 13W a day when placed on the table it would take approximately 160 years to pay back the full cost of the table. After the cells are paid off they would be able to produce $1.25 worth of electricity per year per table. If cells were applied on more tables throughout campus, very small amounts of energy would be saved.
On a small-scale, with few solar devices implemented in a university setting, the high costs of the devices in conjunction with the low price of electricity do not support a breakeven point in the near term. Only when a large number of devices are implemented would the impact be significant and the costs be reduced. Even still, inside conditions are less than ideal relying on diffused light. It would be a more acceptable option if direct sunlight was being used in outside public spaces. However, certain
intangible or indirect benefits may make the concept of solar devices more economically viable. As the world continues to gain familiarity and confidence in solar energy technology, research and development will continue to accelerate in this field, which in turn will decrease the cost of this technology even further. Users of the solar table can become more conscious of their energy consumption and seek out more sustainable ways of meeting their needs. Finally, education of solar energy technology, especially in a university setting, will create a greater general awareness of the many practical uses of this technology as well as of the importance of developing a self-sufficient community.
If more power is able to be generated by the implementation of these tables in outdoor environments, then the tables will also be able to generate enough voltage to charge larger devices commonly used on a college campus setting, such as laptops and tablets, which increases the usefulness and appeal of the tables overall. To improve the amount of power generated by the table, and thus decrease the payback time, future research and design options for outdoor derivations of the solar table concept will be considered, specifically picnic tables around campus. The challenge presented with outdoor applications is that of weatherproofing the system against the harsh seasonal conditions of Utah and other similar environments. Other applications of solar devices may become more feasible in different public places, especially in conditions that are outside and are exposed to greater levels of sunlight. Future efforts will explore solar picnic tables, solar blinds, solar cars, and solar posters in order to determine if there are other small scale implementations of solar energy devices that prove useful in developing a self-sustaining community.
