Just when you thought ice cube-creation technology had peaked, a team of engineering students from San Jose State University has come up an ice maker that has zero carbon footprint. It’s more than an eco-party trick — consider it an electricity-free alternative to refrigeration and air conditioning, which is critical if you happen to be somewhere off of the electrical grid, like in the developing world or in a disaster zone.
It works like this: the solar icemaker uses a refrigerant liquid that evaporates when exposed to the sun. The vapor travels through pipes that come into contact an absorbent material, which cools when the sun goes down. Once the slow-cooling absorbent hits 104°F, the refrigerant turns back into a liquid and its temperature drops like a rock to below freezing because of pressure differences. Put some water next to the evaporator’s exterior and, presto, ice.
A typical icemaker uses electricity to run a compressor to do this work, but the solar icemaker just uses solar energy, with no moving parts. And the systems are sealed, so barring a leak, they'll never need replenishing. The icemaker makes about 14 pounds of ice per day — more than enough for the margaritas at your end-of-summer barbecue. The students' prototype isn't available yet, but maybe next summer….