Around the same time that mechanical vapor compression was invented in the early 20th century, a variant on EC called indirect evaporative cooling (IEC) also debuted in the United States. IEC cools buildings via the evaporation of water as well, but IEC systems contain a heat exchange unit that isolates the evaporating water from the air that is directed inside the building, thus removing heat from it without adding humidity to it. IEC systems require very little energy to run, but are difficult to manufacture due to the complexity of the heat exchange unit, which makes them expensive and their performance difficult to optimize. As a result, they have remained a distant second fiddle to mechanical vapor compression units, which dominate the market. Jack Alvarenga, M.S. and Jonathan Grinham, D.Des. are working to change that by infusing 21st-century technology into IEC systems, allowing them to effectively cool air at low cost in both humid and dry climates. Their technology, dubbed cold-SNAP (short for cold Superhydrophobic Nano-Architectured Process), uses up to 75% less energy than mechanical vapor compression air conditioners, and relies on water rather than environment-damaging refrigerants.
cold-SNAP achieves its high performance thanks to the integration of old and new: ceramic, one of the earliest, cheapest, and most widely available building materials; and a novel surface coating developed recently in the lab of Wyss Core Faculty member Joanna Aizenberg, Ph.D. The coating's nanoscale roughness makes it super water-repellent and, when applied to a slab of highly water-absorbent ceramic, the result is a very efficient heating exchange unit that can effectively isolate evaporating water from cooled air. Because ceramic is very malleable, an entire heating exchange unit can be produced via the extrusion or 3-D printing of a single 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 flow of dry air, coupled to a water pump, fan, and controls. cold-SNAP creates a ceramic-based heat exchange unit for indirect evaporative cooling that can be manufactured in one step and easily modified to optimize the surface area available for heat transfer, making them cheaper and more efficient than current air conditioners. Credit: Wyss Institute at Harvard University
Preliminary studies have indicated that the cold-SNAP system can be up to four times more efficient than conventional air conditioners as measured by the Coefficient of Performance (COP), which is the ratio of how much useful cooling a system provides over the amount of energy required to produce that cooling. The better a system's COP, the less energy it consumes, and the lower its operating cost. This aspect is crucial, not only so that cold-SNAP can compete with today's conventional air conditioners, but also because the world's poorest people live along the equator, where air conditioning is most needed but electricity is prohibitively expensive. The team is currently exploring different manufacturing techniques, and is gearing up for a pilot study this summer to see how the system performs in real-world hot and humid conditions.
https://techxplore.com/news/2020-04-technology-cools-air-adding-humidity.html
cold-SNAP achieves its high performance thanks to the integration of old and new: ceramic, one of the earliest, cheapest, and most widely available building materials; and a novel surface coating developed recently in the lab of Wyss Core Faculty member Joanna Aizenberg, Ph.D. The coating's nanoscale roughness makes it super water-repellent and, when applied to a slab of highly water-absorbent ceramic, the result is a very efficient heating exchange unit that can effectively isolate evaporating water from cooled air. Because ceramic is very malleable, an entire heating exchange unit can be produced via the extrusion or 3-D printing of a single 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 flow of dry air, coupled to a water pump, fan, and controls. cold-SNAP creates a ceramic-based heat exchange unit for indirect evaporative cooling that can be manufactured in one step and easily modified to optimize the surface area available for heat transfer, making them cheaper and more efficient than current air conditioners. Credit: Wyss Institute at Harvard University
Preliminary studies have indicated that the cold-SNAP system can be up to four times more efficient than conventional air conditioners as measured by the Coefficient of Performance (COP), which is the ratio of how much useful cooling a system provides over the amount of energy required to produce that cooling. The better a system's COP, the less energy it consumes, and the lower its operating cost. This aspect is crucial, not only so that cold-SNAP can compete with today's conventional air conditioners, but also because the world's poorest people live along the equator, where air conditioning is most needed but electricity is prohibitively expensive. The team is currently exploring different manufacturing techniques, and is gearing up for a pilot study this summer to see how the system performs in real-world hot and humid conditions.
https://techxplore.com/news/2020-04-technology-cools-air-adding-humidity.html
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