As a result, Wang Peng, an environmental engineer at the Hong Kong Polytechnic University, and his colleagues thought of another use for condensed water: a coolant for solar panels. The researchers pressed a 1-centimeter-thick sheet of the gel onto the bottom of a standard silicon solar panel. The idea is that during the day, the gel absorbs heat from the solar panels and releases water vapor. Evaporating water cools the solar panels, just as sweat evaporating from the skin cools the human body.
The researchers found that the amount of gel needed depends largely on the humidity of the environment. In a desert environment with 35% humidity, 1 kg of gel is needed per square meter of solar panels to cool; in a muggy area with 80% humidity, only 0.3 kg of gel is needed per square meter of panel cooling.
Regardless of the application scenario, the result was the same: the temperature of the water-cooled solar panels dropped by 10 degrees Celsius. On May 11, Wang Peng and his colleagues reported in “Nature-Sustainable Development” that in an outdoor test, the power generation of the panels increased by an average of 15% and a maximum increase of 19%, and the wind may have enhanced the cooling effect. .
But Zhou Jun pointed out that rainwater will dissolve the calcium chloride salt in the gel, weakening its water absorption performance. Wang Peng said that the gel is located at the bottom of the solar panels and should be able to avoid rain. At the same time, their team is developing a second-generation gel that will not degrade even when exposed to water.
Another design option is to have a device that collects and recondenses the water after it has evaporated. The water can be used to clean dust accumulated on solar panels, or it can be stored for drinking, solving urgent needs in arid regions, Wang Peng said.