Performance of Photovoltaic Cells in Undersea Environment

Abstract

Photovoltaic solar cells can serve as a reliable source of electric power for electronic instrumentation in temporarily or permanently submerged marine systems in the form of bottom installations, buoys, or remotely controlled unmanned vehicles. The power output of submerged solar cells is a function of solar insolation intensity on the water surface, depth of submersion, optical properties of water, temperature, and the orientation of the cell surface with respect to the sun. Experimental data was generated by submerging solar cell panels in different bodies of water with 2.5 to 95 feet (0.75 to 29 meters) visibility range, as defined by the observation of a submerged standard 12-inch Secchi disc, and measuring their performance under load. The power output of horizontally oriented, upward facing, photovoltaic cells submerged to the visual contrast limit/depth was found to be a constant, equal to approximately five to ten percent of the power generated by upward facing horizontally oriented cells in atmospheric environment. At lesser depths, the power output of the cells increased, until in the splash zone the output was essentially the same as in atmospheric environment. Based on these findings it can be concluded that high efficiency silicon solar cells can serve as a practical electrical power supply in electronic devices for marine applications, providing that their depth of submersion is less than the visual contrast limit at the dive location.