Solar steam generation is a useful method for desalination and sterilization. Current research is focused on designing devices with improved energy conversion, enhanced solar absorption, heat localization, water supply, and vapor transportation. But who would have thought that the latest breakthrough could lie so close to home, or even, on your dinner plate?!
Mushrooms – typically considered a food, a garnish, or medicine – have just added “solar harvesting steam generator” to their resume.
In Advanced Materials, researchers from Nanjing University use Shiitake mushrooms to harvest solar energy for steam generation.
Shiitake mushrooms, in their natural and carbonized form, can achieve ≈62% and ≈78% conversion efﬁciencies under 1 sun illumination, respectively. This success is attributed to their natural structure, which is perfectly suited for solar absorption and steam generation.
The Shiitake mushroom has an umbrella-shaped black pileus (see figure) that is perfect for soaking up solar radiation. They are incredibly porous, with hydrophilic fibrous stipes that pump water directly into the mushroom using capillary action and permit vapor to escape from the mushroom top. This structure has just the right ratio of black pilei and fibrous stipes to suppress heat loss via conduction to bulk water, and the large surface area for evaporation efficiently suppresses heat loss via radiation and convection.
As a low-cost material ($2 per kg), mushrooms are an inspiring pioneer in the development of high-performance solar–thermal conversion devices.