Solar Energy Conversion by Using Solar-pumped Laser and High-temperature Steam Electrolysis

Abstract

Incoherent solar radiation, collected by the solar concentrator installed in the Solar Energy Laboratory of our Institute, is successfully converted to a coherent laser radiation, i. e. the concentrated solar radiation is used to pump a water-cooled Nd: YAG laser rod 10 mm in diameter and 100 mm in length. The maximum output of the laser is 40 W in multimode, the highest output power reported so far in solar-pumped laser.
The high-temperature steam was electrolyzed using zircon ia ceramics as an electrolyte and hydrogen was produced with high efficiency of about 92%. The overvoltage of Pt electrode is analysed from temperature dependence of the relationship between electrolytic current and applied voltage. SEM observations of Pt electrode revealed that porosity of electrode greatly decreased after electrolysis. The decrease in porosity is considered as an origin of overvoltage.
From these fundamental investigations, it is concluded that solar-pumped laser and hightemperature steam electrolysis have a potential ability as new energy plants and that the construction of a solar hydrogen system is expected.