Modeling Analysis of Solar Driven Hydrogen Generation via Water Harvester and Solar Panels under Hot and Cold Climate Conditions

Abstract

A transient analysis of a standalone hybrid system that integrates atmospheric water harvesting of desorption solar still and PV solar panels supplying power to an electrolyzer for green hydrogen production is proposed and analyzed. The study is carried out and assessed under the climate conditions of Alexandria, Egypt. The harvesting unit produces the freshwater and the panels produce the power required for powering the electrolyzer. The subsystem models for the PV panels, harvesting silica gel unit, and electrolyzer, as well as the linkage model of the overall hybrid system, are presented using MATLAB, validated, and analyzed. Subsystems and the hybrid system performance parameters are investigated and evaluated. Moreover, the impact of solar intensity on the performance of the system is evaluated. The results show that the PV current, voltage, and power for the electrolyzer input rise with rising the solar intensity yielding together hydrogen and freshwater production rates with electrolyzer efficiency in the range of 70–71%. In the harvesting solar still, silica gel temperature rises with hourly solar intensity reaching its peak in the afternoon. At 1 m2 of the PV Panel area, 0.0275 kg of hydrogen is produced in summer and requires a solar still area of 0.022 m2 with a silica gel mass of 1.312 kg. PV, AWH solar still, electrolyzer, and overall system efficiencies have the ranges of (11.2–6%%), (48 to 18%), (70.78 to 69.34%), and (1.7 to 0.6%) with changing the solar intensity from 400 to 1200 W/m2, respectively.