A solar energy system that combines electricity generation with thermal energy production is being advanced by researchers from Northern Technical University and Al-Kitab University in Iraq. The design incorporates photovoltaics (PV) to supply power and a Trombe wall (TW) as a passive solar heating system to deliver thermal energy.

The TW absorbs solar radiation on its outer face and transfers it through the structure by conduction for distribution to internal spaces. The combined system is under development to provide hot water, hot air and electricity, with the TW system also serving to cool down PV module temperature.

Two test chambers were equipped with solar panels and reflective mirrors to determine optimal design parameters. One chamber used a heat exchanger placed behind the PV modules, while the other had no heat exchanger. The mirrors were placed on the right and left sides of the south face of the system and were fixed to the ground using an iron base. Two DC fans were set up on top and two at the bottom of each chamber and a water pump was used to circulate the water inside the heat exchanger.

An inclination angle for the reflective mirror of 30° proved optimal when using the heat exchanger. This arrangement afforded the highest daily electrical efficiency of 13.86%. The use of water passing via the heat exchanger behind the PV panel was observed to increase overall performance by lowering the PV panel temperature.

The research is published in Energy Reports.