Researchers from Saudi Arabia and Algeria have developed a new photovoltaic-thermal solar collector design that lowers solar panel temperatures by 9 degrees without consuming water or electricity.
The passive cooling system reached 31 percent thermal efficiency in simulations while aiming to reduce the temperature-related efficiency losses that affect solar panels using natural airflow.
Photovoltaic-thermal, or PVT, collectors are hybrid units that combine photovoltaic solar cells with a thermal heat collector. Standard solar cells convert only a portion of incoming sunlight into electricity, while the remaining solar energy turns into heat. As panel temperatures climb, the electrical voltage drops and power generation falls. By drawing heat away from the cells, a PVT collector protects electrical output while capturing usable thermal energy.
Stepped air channel and aluminum fins
To provide completely passive cooling, the researchers placed a stepped air channel behind the solar panels. As a panel warms up in the sun, a layer of heated air forms along its rear surface and acts as a barrier that limits heat transfer. The stepped channel geometry disrupts this insulating air layer so heat can escape more effectively.
The collector also uses perforated V-shaped aluminum fins inside the air channel. These fins expand the total heat transfer surface while increasing air mixing and turbulence behind the solar cells.
Unlike active cooling systems that depend on mechanical hardware, the collector does not need a fan, a pump, or an external energy source to circulate air. Instead, temperature differences inside the channel create natural buoyancy forces that cause warm air to rise and pull cooler air through the system. Eliminating external cooling power removes additional energy consumption and is intended to reduce maintenance requirements.
Simulation results and power output
The researchers examined the collector design using computational fluid dynamics, or CFD, in ANSYS Fluent software. CFD is an engineering simulation method that uses numerical models to analyze how fluids and gases flow and transfer heat across physical surfaces.
The simulation results showed that lowering the panel temperature increased both electricity and heat generation performance. The new design achieved a calculated thermal efficiency of 31 percent and an electrical efficiency of 14.8 percent, outperforming a compared reference system that recorded 29.4 percent thermal efficiency and 14.6 percent electrical efficiency.
At peak performance, the new collector reached a maximum power output of 400 watts of thermal power and 180 watts of electrical power. Improved heat distribution and airflow turbulence reduced the photovoltaic surface temperature by 9 degrees.
Payback period and carbon emissions
According to an economic analysis by the researchers, the collector has a financial payback period of 5.8 years under clear sky conditions and 7.2 years in cloudy weather. The energy payback time, which measures how long a system must run to generate the amount of energy used to manufacture it, was calculated at 0.86 years.
The researchers estimated that a 10-panel installation could prevent 3.2 tons of carbon dioxide emissions per year, providing a total emission reduction of 80 tons over 25 years.
