Nano-material could improve adsorption technology

A nano-material could drastically improve adsorption cooling, thanks to its high adsorbing properties. The material, engineered by Pacific Northwest National Laboratory (PNLL), USA, was created using nanoscopic structures, that self-assemble into complex three-dimensional shapes which prove to be very porous, as they give a larger surface area for water molecules to cling to. As a result, the material can trap up to three or four times more water than silica gel, which enhances efficiency and could help cut the size of chillers by 75%, thus making them more competitive, according to Yunho Hwang, Secretary of the IIR’s Commission B2 and Professor at the Center for Environmental Energy Engineering at the University of Maryland.  
The material also binds less strongly to water molecules, which reduces the amount of heat needed to free the water molecules, making the process more efficient and speeding up the adsorbing and desorbing of water by 50-100-fold. It can also adsorb other refrigerants. The chillers could be particularly useful for cooling with hot water from solar water heaters as they can efficiently use relatively low-temperature heat, but the main challenge for this approach could be synchronizing demand for cooling with the production of heat thanks to thermal storage, which can prove costly.
The PNNL researchers were granted USD 2.54 million from the Advanced Research Projects Agency for Energy to demonstrate the material in a cooling system. Under the grant, they have 3 years to optimize the material’s performance and incorporate it into a small demonstration chiller.