Fresnel Lenses were used in #Lighthouses since the 1820's until the mid 20th century. They were known as "the invention that saved a million ships".
[Image: Stock image of the fresnel lens at the Pensacola lighthouse]
A new designed linear #FresnelLens #SolarConcentrator based on spectral splitting for passive cooling of solar cells
by Soroush Kiyaee, Yadollah Saboohi, and Alireza Z. Moshfegh
15 February 2021
Highlights
• A new design of a Fresnel lens based on spectral splitting.
• Passive cooling of a solar cell through diffracting the undesired spectrum portion.
• Optical-thermal simulation of the concentrator system.
• A temperature-dependent model by considering conduction, convection, and radiation.
• Comparison of different lenses in temperature and electrical efficiency of the cell.
https://www.sciencedirect.com/science/article/abs/pii/S0196890420313054
#FresnelLens #SolarEnergy #SolarSundays #SolarSunday #Renewables #RenewablesNow #SolarPunkSunday
#Solar #Desalination Using #FresnelLens as Concentrated Solar Power Device: An Experimental Study in Tropical Climate
Wing Sum Choong, Zhi Yong Ho and Rubina Bahar, October 2020
"Solar desalination is a renewable energy-driven method that produces freshwater from saline/brackish water. Conventional solar desalination units are equipped with an inclined transparent condensing plate placed over a feedwater basin containing saline water. The process is limited to a small quantity of production because of scattered solar irradiation and the unavailability of solar heat due to intermittent cloudy weather. In this study, a Fresnel lens has been used to concentrate solar energy onto a spot to increase the local temperature of feedwater and the evaporation rate. Flat Fresnel lenses on a double sloped passive solar still were used, where the focal points were adjusted to fall directly on the feedwater. The experiments were conducted for two different geometries and alongside the comparison between the conventional and the modified solar still; the number of Fresnel lenses was also varied. Saline solution with a concentration of 20,000 ppm was used as the feedwater. The research is aimed to be implemented for producing freshwater in the natural weather conditions of Malaysia. It was found that using two Fresnel lenses instead of a single large one gives a boost to the production of freshwater per unit solar irradiation by 39%. The produced water has a total dissolved solids (TDS) value of 37 ppm, which is well within the drinking water standard range according to the World Health Organization."
https://www.frontiersin.org/articles/10.3389/fenrg.2020.565542/full
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