There seems to be a lower size limit for conventional, compressor-based refrigeration. The result is that portable cooling devices are always simple fans, or at best, evaporative cooling units. What prevents conventional refrigeration and air conditioning from working at sizes much smaller than a dorm refrigerator?
In: Technology
Basically, it’s physics. You can certainly create a smaller AC unit, but you’ll have a smaller amount of cool air created. If you look at your typical AC unit, a split system with an indoor unit and an outdoor condenser….you’ve got a system where, outdoor you have a coil that goes around and around with coolant running through it and you’ll note there are these thin fins that surround the coolant line. The fan blows air through the fins and it supercools ” the state of the coolant being less than than the temp it would normally freeze but it stays liquid due to pressure” so it goes around and around gets colder and colder then heads into the house really cold and enters the coil above the furnace typically and kicks on the fan so the fan blows inside temp air over a, now, really cold coil….the warmer air is raised about 20+ degrees but the liquid now turns to a gas….” phase change” …. The gas now travels through the refrigerant line back to the outdoor coil and does another phase change back to liquid. If you can imagine, it’s basically a system, a circle which grabs heat in the house and takes it outside and releases it, heads back in to grab more and takes it back outside to release it… .over and over and over. “side note this system works in reverse with a heat pump” So, all that to say there is no way to hack this system, no matter how an AC is created it always needs to grab head inside and take it outside to release…window unit, rooftop unit, split system….whatever. And to remove heat you must find a way to cool the coolant…..that takes moving air and surface area “the fins” and the exact same thing needs to happen inside. So you can imagine….smaller means less cool air. I hope I was able to give you some understanding of the restrictions related to making AC units smaller. They have actually gotten somewhat smaller over the years, but they do bump up against the same physics restrictions no matter what they do. They can mess with metals that transfer heat faster, speed of airflow, types of refrigerant etc…but many times making a product available for the public means using easily available metals and easily created refrigerants…so no groundbreaking changes likely any time soon.
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