A team of engineering students from San Jose State University has solved this apparently contradictory idea in a design for an ice-maker that leaves no carbon footprint at all. A must-have for the many places where electricity has been a luxury item, beyond the reach of local pocketbooks. If it could be commercialized - perhaps with some attention paid to aesthetic issues! - it would be great to have solar refrigeration. Simple tech can achieve low carbon goals.
Unlike the usual ice-making machines that supply the compressor with electricity, this solar-powered ice-maker uses refrigerant liquid that just evaporates when exposed to the sun, and the whole thing works without any moving parts. All of the systems are sealed, so barring a leak, they would never need replenishing.
The process uses refrigerant liquid that turns to vapor as the sun heats up during the day. The vapor travels through pipes that come into contact with an absorbent material, cooling when the sun goes down. But once the absorbent material heats up to 104°F in the heat of the sun, the refrigerant suddenly becomes liquid again, and that drops the temperature below freezing because of pressure differences. By simply putting water next to the evaporator this process turns the water into ice.