On July 14th, take a moment to celebrate one of the most significant but under-appreciated inventions of the modern world: mechanically produced ice!
If you don’t think ice is worth making a fuss over, try this thought experiment. Close your eyes and imagine you’re sitting on your patio on a mid-August afternoon. The sun his still high in the cloudless blue sky, and a small breeze barely ruffles the leaves on the nearby trees. The temperature is in the high 80s – maybe even in the 90s. The kids have abandoned the swing set for video games inside, and even the dog is too hot to move much. That’s okay – the chores are all done for the day and it’s time to relax. You reach over and pick up your glass from the table beside you and take a long swig. Ah – there’s nothing quite like a little tepid lemonade to make you feel refreshed!
Wait, tepid lemonade? Who wants that? When we think of summer refreshment, the clatter of ice cubes in a glass is one of the first things to come to mind, right? Just imagine how disappointing that lemonade – or ice tea, or soda pop, or even your summer wine cooler – would be without a little bit of ice to keep it cool and satisfying. In fact, ice cubes are so integral to in our pictures of summertime activities, it’s hard to imagine a time when iced drinks in the summer where anything but ordinary.
But before 1850, ice in the summer was no guaranteed treat – especially in southern climates, where people had to import ice from the north each year at great expense, and hope that it wouldn’t all melt before the end of the hot weather! But Dr. John Gorrie changed all that forever at a party in Florida on July 14th, 1850, by serving guests trays full of the first ever mechanically produced ice.
The Father of Refrigeration and Air Conditioning
As a doctor in mid-19th-century Florida, John Gorrie was driven by his desire to provide treatment to patients suffering from tropical diseases such as malaria and yellow fever. Ice was essential to reducing fevers and providing general cooling in his treatment rooms. But natural ice – carved from frozen lakes and rivers – had to be shipped to Florida from northern climes, stored in sawdust packed ice houses, and was generally used up or melted by midsummer – just when Gorrie’s patients were most in need of the chilly relief. So Gorrie set about finding a way to make ice himself.
Following in the footsteps of earlier experiments in refrigeration (William Culle in 1748, Oliver Evans in 1805, and Jacob Perkins in 1834) Dr. Gorrie successfully designed, patented, and built a prototype of his ice making machine. And even though his business efforts to capitalize and market the machine failed badly (he died just five years later, impoverished and humiliated), he is remembered today as the father of refrigeration and air conditioning, and a statue honoring him can be found in the National Statuary Hall in Washington D.C.
The Science of Ice Making
Gorrie’s ice making machine was about twice the size of a modern household refrigerator, but the principles at work were pretty much the same. Like today’s air conditioners and refrigerators and freezers, the production of ice relies upon what’s called “vapor compression refrigeration.” Gorrie himself described it like this:
“If the air were highly compressed, it would heat up by the energy of compression. If this compressed air were run through metal pipes cooled with water, and if this air cooled to the water temperature was expanded down to atmospheric pressure again, very low temperatures could be obtained, even low enough to freeze water in pans in a refrigerator box.”
Today’s ice makers do much the same thing, using chemical refrigerants as the gas that cycles through the four-part system (evaporator, condenser, compressor and expansion or throttle valve). This diagram gives a basic overview of what the refrigeration cycle looks like:
The whole process relies upon the natural properties of the refrigerant to extract or release heat as it changes between liquid and vapor states, depending upon the pressure exerted by the system.
There are different ways to turn this scientific construct into an ice making machine. For our portable ice makers, metal rods are connected to the evaporator coil. As the expanding gas passes through the coil, the evaporator and the rods drop in temperature. The rods are lowered into a bin of water and ice forms around them. Here’s a peek inside at ice forming:
Believe it or not, this is the fastest way to get ice available! A portable ice maker can deliver a load of ice every ten minutes, compared to the 30 minutes or so it takes to make ice in your freezer. Plus, it can sit right on top of your kitchen counter – a lot more conveniently sized than Dr. Gorrie’s original ice maker.
So this coming Sunday, while you enjoy your icy beverage and take a break from the heat in your air conditioned living room, take a moment and raise a toast to Dr. Gorrie, the Original Father of Cool!