FINAL ILLUMIN.docx



Illumin PaperWRIT 340Prof Martha TownsendJenny YuMay 2, 2014A Cooler and Brighter CityTaking advantage of the sunIn the north east where snow is an issue, heated driveways and sidewalks are implemented, melting away the snow and ice for a safer commute. Taking advantage of the sunlight available in southern California may be the key to help preserve the environment. Solar energy is an effective energy source that can be used in many different settings and environments. Many homes are significantly decreasing their electricity bills by switching to solar energy and universities are beginning to look into new ways to incorporate solar through buildings or sidewalks. With more focus on discovering more efficient methods of solar panels, not only can we can help decrease the burning of fossil fuels and the production of carbon dioxide gases that harm the environment, but also cool urban infrastructure with sidewalk, window, and sidewalk alternatives. We can significantly improve the urban infrastructure by implementing solar and alternative reflective solutions.Implementing SolarSolar Rooftops and WindowsAs government incentives are a bonus to investing in solar panels, people are switching over at a speedy pace, lowering their monthly electricity bills and providing their own power. The semiconductor consists of a panel of many silicon solar cells that generate electric currents. These photovoltaic panels that harness solar energy are one of the most economical alternative energy sources, covering rooftops and windows all over the country where sunlight is abundant. Solar SidewalksImagine walking to class and stepping on solar panels that help power the lighting in your next classroom or are used to light the pathway at night time. Solar sidewalks are an innovative idea and have successfully been implemented at the George Washington University’s Virginia Science and Technology campus. Even though the university has only installed a 100 square foot sidewalk, it produces 400 watts which is enough solar energy to power the 450 LED lights that are underneath it to light up the path at night, and the remaining energy source is channeled to their nearby Innovation Hall. This project named "The Solar Walk" is created using Onyx Solar and photovoltaic panels. Photovoltaic panels use solar cells to convert solar radiation into electricity. Figure 1 pictures the weight “The Solar Walk” can withstand, depicting four football players with an average weight of 200 lbs each.Figure 1. The solar sidewalk can hold the weight of about 400 kilograms (882 pounds). ?Image from: Solar EfficiencyThe issue with solar energy conversion is finding low cost solutions that do not limit the photovoltaic conversion efficiency. Some solutions include using concentrated sunlight in a hybrid thermophotovoltaic conversion process which is compatible with the conventional silicon photovoltaic cells. This process can potentially increase the efficiency of a single-junction photovoltaic cell from 33% to 73% using low-energy photons. Another solution is using the thermal energy storage of a corn-based bioethanol plant to connect with solar panels to power a solar-assisted steam generation system with heat storage, improving plant profitability and energy consumption and lessening the use of fossil fuels. Solar panels have also found to be most efficient when using a different solar cell design. By formatting the cells into a Lego pattern, light is allowed to bend in a way that boosts solar efficiency. Figure 2a shows the lego pattern of each layer and Figure 2b shows the scattered absorption of the cross section efficiency for the different metals used and depicts the significance of metal choices. The metal used for scattering nanoparticle arrays is crucial in optimizing photocurrent improvements. While current solar panels use gold and silver materials to construct, using enhanced photovoltaic cells made of different materials such as aluminum or other metals can make solar panels more affordable in the future. 344805017208500(a)8572510160Figure 2a. "Lego" patternFigure 2b. "Lego" metal layers of a solar panel to efficiently trap light. ?00Figure 2a. "Lego" patternFigure 2b. "Lego" metal layers of a solar panel to efficiently trap light. ?Cooling the Urban InfrastructureGreen Roofs, Cool Buildings, and Cool PavementsA problem that the urban environment experience is the increased surface temperature of the rooftops, sides of buildings, and the ground, and the negative impacts on the microclimate of the immediate surroundings. The Walt Disney Concert Hall is an example of a location with increased ground temperature in the vicinity of the building. The study of measuring the visual glares of the building poses possible other alternatives to the thermal impact on the environment. Due to the many reflective surfaces of the Walt Disney Concert Hall, overheating can occur in surrounding buildings and even outdoors. The ground surface temperature on a summer day was averaged at 125 ° F and some curb temperatures to be about 138 ° F. Solutions to this effect are reflective coatings such as highly reflective roofs and highly reflective pavements on urban environments to lower surface temperatures of the buildings and sidewalks. The cool roof and cool pavement may reflect solar radiation from the pavement however and may cause discomfort for pedestrians as it raises the human body temperature. Roofs covered with vegetation are an excellent way to help reduce building heating as green roofs include drainage and insulation. Figure 3 shows the layers of an example of a green roof. Figure 3. Green roof system exampleImage modified from: types of pavement assess which implementation best stabilizes surface temperature. Exposed to direct sunlight and shaded areas, the most ideal pavement was found to be made from open cell concrete blocks filled with vegetation. Also by investigating the uses of surface temperature sensors and data logging samples, fourteen types of reflective coatings were used to find the optimal coating for thermal performance. Figure 4 shows the samples placed on the modulated platform. Figure 4. Coatings laid out horizontally and insulated from below.The results were that the white colored coatings performed better than the aluminum colored coatings because the aluminum remained hotter over time due to a low infrared emittance. Cool coatings exhibited the best thermal performance\but also experienced degradation due to weathering. Applying these coatings could reduce surface temperatures, improve building comfort, and reduce cooling energy usage.The future is cool and brightBy implementing these changes, we are able to significantly improve the urban infrastructure, cooling and protecting the environment. Solar and the other alternative green and cooling solutions are ideal to developing a newer, cooler, sustainable city. About the Author:Jenny Yu was born and raised in Los Angeles and is studying Environmental Engineering. Bibliography 1. Boriskina, Svetlana V., and Gang Chen. "Exceeding the Solar Cell Shockley- Queisser Limit via Thermal Up-conversion of Low-energy Photons." Optics Communications 314 (2014): 71-78. Elsevier. 01 Mar. 2014. Web.2. Brunet, Robert. "Minimization of the Nonrenewable Energy Consumption in BioethanolProduction Processes Using a Solar-assisted Steam Generation System." Alche Journal 60.2 (2014): 500-06. Wiley Online Library. 28 Oct. 2013. Web.3. Dos Reis, F.S. "A Low Voltage Electronic Ballast Designed For Hybrid Win-Solar Power Systems." Industrial Electronics, 2007. ISIE 2007. IEEE International Symposium on (2007): 3066-071. Web.4. Hylton, N. P. "Loss Mitigation in Plasmonic Solar Cells: Aluminium Nanoparticles for Broadband Photocurrent Enhancements in GaAs Photodiodes." . Nature Publishing Group, 07 Oct. 2013. Web.5. Kondo, Yasushi, Takeshi Ogasawara, and Kunihiro Udoh. "Influence of Radiation Reflected by Cool Pavement on Thermal Sensation of Pedestrians." Journal of Environmental Engineering 74.637 (2009): 323-30. Web.6. Mascaro, Juan J. "Shaded Pavements in the Urban Environment – a Case Study." Taylor and Francis, 21 Mar. 2012. Web.7. Meehan, Chris. "GWU Introduces World's First PV Sidewalk." Solar Reviews. N.p., 08 Oct. 2013. Web.8. Rogers, James. "Solar Innovations: Sidewalks, Windows, and Legos?" Sierra. N.p., 31 Oct. 2013. Web.9. Saravanan, S. "Instantaneous Reference Current Scheme Based Power Management System for a Solar/wind/fuel Cell Fed Hybrid Power Supply." International Journal of Electrical Power & Energy Systems 55 (2014): 155-70. Feb. 2014. Web.10. Schiler, Marc. "Microclimatic Impact: Glare around the Walt Disney Concert Hall." Proceedings of the Solar World Congress 1 (2005): 511-16. Web.11. Synnefa, A., M. Santamouris, and I. Livada. "A Study of the Thermal Performance of Reflective Coatings for the Urban Environment." Solar Energy 80.8 (2006): 968-81. Science Direct. Aug. 2006. Web. ................
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