Evaporative cooling: continuation of the Cold-Snap project at Harvard University

Tests show that Cold-Snap evaporative cooling technology would be effective in humid climates, while limiting water consumption.

A team from Harvard has been working for several years on a technology called Cold-Snap (short for Cold Superhydrophobic Nano-Architectured Process).
This technology was featured in an IIR news item in 2020*.
Most evaporative cooling technologies only work well in hot, dry climates because they add moisture to the surrounding air**.
Cold-Snap technology is based on an indirect evaporative cooling system: spaces are cooled by water evaporation, but the system has a heat exchange unit that isolates water vapour and air, which removes heat without adding moisture.
The Cold-Snap system uses a mixture of ceramics and a new coating developed by the researchers. The nanoscale roughness of the coating makes it super water-repellent and, when applied to a ceramic tile with high water absorption, it produces a highly efficient heat exchange unit that can effectively isolate the evaporating water from the cooled air. Because ceramic is very malleable, it is possible to produce a complete heat exchanger by extrusion or 3D printing in one piece, and its shape can be adjusted to maximize the surface area available for heat transfer and evaporation. The hydrophobic coating is then selectively applied to the components that will manage the dry air flow, coupled with a water pump, a fan and controls. 
Last August, the team of Harvard researchers tested their system on hot, humid days in Boston at the Harvard Experimental Center. The results are promising, as the scientists say: " We’re cooling at a much higher efficiency than a typical AC unit, we’re able to achieve a cool temperature, and we’re able to do all that using less water than standards ask for".
The researchers will continue to analyse their data and develop their technology, in order to demonstrate that this system is efficient enough to be put on the market. 

* https://iifiir.org/en/news/evaporative-cooling-without-adding-humidity  

** https://iifiir.org/en/fridoc/evaporative-cooling-27-lt-sup-gt-th-lt-sup-gt-informatory-note-on-refrigeration-138322


Source : Fast Company

Image: https://wyss.harvard.edu/technology/cold-snap-eco-friendly-air-conditioning/