Experimental study to enhance the performance of a hybrid solar distiller system under the harsh climatic conditions in Iraq

• Development of a hybrid PV/T system integrating a solar still with PV panels for simultaneous electricity and freshwater production. • Comparative evaluation of a conventional system (CSS) and an enhanced system (ESS) with a black-painted natural stone layer. • The enhanced system achieved 7.2 L/day/m² of freshwater and 1.26 kWh/day/m² of electricity. • Water productivity improved by 33 % in ESS, with 1 cm water depth showing superior thermal performance. Freshwater scarcity and electricity shortages are among the biggest challenges in arid regions, with recurring sand and dust storms as the primary impact on solar energy systems. This study experimentally evaluates a hybrid photovoltaic/thermal (PV/T) distillation system designed to produce freshwater and electricity simultaneously. Two identical units were fabricated: a conventional solar still (CSS) and an enhanced solar still (ESS) equipped with a copper heat exchanger and a 1 cm Black stone layer. At water depths of 1 cm and 3 cm during May 2025 under different weather conditions (sunny, semi-cloudy, and sandstorm days), tests were conducted in Kirkuk, Iraq. According to the results, the enhanced solar still (ESS) achieved a maximum freshwater production of 7.2 liters/day/m² and electricity generation of 1.26 kWh/day/m², resulting in a 33 % improvement in water production compared to a conventional solar still (CSS). The pool water temperature increased at a depth of 1 cm by 5–10 °C compared to a 3 cm depth, leading to higher evaporation rates. The overall thermal efficiency of the ESS increased by 12–15 %, while the electrical efficiency remained stable at 10–14 % despite fluctuating climatic conditions. These findings confirm that the proposed hybrid PV/T system enhances heat utilization, reduces thermal losses, and provides a practical, low-cost solution for addressing water and energy shortages in arid regions.