The researchers from Saudi Arabia created a new material improving the solar panels’ performance by 12% and doubling their service life. This is a hydrogel component capable of absorbing moisture from ambient air during the night time and cooling the panels during the day time by means of evaporation. The technology was tested in real environment, and the results are published in Materials Science & Engineering R scientific journal.
The scientists from the Science and Technology University named after King Abdalla proposed an inexpensive way to cool solar panels by using a specialized composite material based on sodium polyacrylate and lithium chloride. This material is applied to the reverse side of a panel. To receive such a material, the components are mixed in 2:1 proportion and formed into flat plates setting solid: this proportion provides for resistance to high humidity (over 90%) and temperature (above 30 °C). During the night time, lithium chloride actively absorbs moisture from ambient air, and sodium polyacrylate captures and keeps it due to its hydrophilic properties. During the day time, water evaporates providing for cooling without the need to replace the material.
The system demonstrated high performance during the laboratory tests. Given 1 KW/m2 solar radiation, the cooling output reached 373 W/m2 during the first 3 hours, and after 12 hours it was circa 187 W/m2. When simulating natural environment, the average output constituted 160 W/m2, and the maximum output — 247 W/m2 during the morning hours.
In real conditions (37 °C and 53% of relative humidity), the system provided for stable cooling at the level of 175 W/m2. In the middle of the day the surface temperature fell down to 14 °C allowing for increasing the efficiency of converting solar energy into electricity from 13.1% up to 14.7% (circa 12% increment). Field testing was performed for 21 days in the city of Thuwal (Saudi Arabia) and for one month in Buffalo city (the USA). Small silicon solar panels 54×54 mm were used for testing. 7-mm layer of the composite material was applied to their back surface, and after absorbing the moisture this layer grew up to 10 mm.
The outcomes of the research allowed for identifying that on top of performance improvement the new technology doubles the solar panels’ service life and reduces the electricity generation costs by 18%. The cost of the material is USD 37 per square meter, which is significantly cheaper vs other cooling methods.
