Dilip Krishna Nandakumar
National University of Singapore, Singapore
Title: Harnessing ambient humidity for energy conservation, harvesting and environmental applications
Biography
Biography: Dilip Krishna Nandakumar
Abstract
Ambient humidity is ubiquitous and is widely considered a redundant resource demanding an additional expense of energy to maintain it at thermally comforting levels. With research on alternative sources of energy primarily blinkered towards transduction of solar, wind, tidal and other forms of ambient energy sources directly into electrical signals, a holistic approach to harness the omnipresent humidity is relatively scarce. The earth’s atmosphere has a staggering 13 trillion kiloliters of water, which can be utilized for various energy and environmental applications. Conventional hygroscopic materials do not offer a sustainable route in utilizing humidity as they suffer from low water uptake and high energy requirement for water release. Intrigued by these challenges, we have developed a novel super-hygroscopic hydrogel with water absorption capability over 4X its own weight and ultra-low temperature of water release. The synthesized hydrogel exists in two distinct states hydrated (H) and dehydrated (DH) depending on the level of relative humidity (RH). The hydrogel displays interesting humidity-triggered changes in optical, electrical and electrochemical properties that were exploited for energy conservation applications. We have developed proof-of-concept models to demonstrate the energy conservation applications in the form of a thermo-hygroscopic privacy window that operates at no energy expense, an infrared radiation blocking windscreen that aids in reducing heat buildup inside rooms leading to mitigated air-conditioner usage, a conductive medium for reusable flexible electronic substrates and an electrochemical cell for energy generation. Additionally, we have also developed a novel solar energy triggered technique to pull clean water from the sea by exploiting the humid air space that exists above sea surface. Through multiple absorption-desorption cycles, it is currently possible to harvest up to 14L of clean water per day per kilogram of the hydrogel used. This method opens-up new possibilities for contact-less desalination approaches in the near-future.
