115 Years of Keeping Cool

115 Years ago today, Willis Carrier submitted his drawings of the first Air Conditioner as we know them today. To get a handle on just how long ago that was, the Ford Model T wouldn’t be released until 1908. Cars were a luxury item and people primarily got around with horses, trains, and the odd trolley here and there. Let’s take a look back at what lead to the first air conditioner.


The Paper Problem

To understand the first air conditioner, we need to understand why it was built and the problem it was intended to solve. It was commissioned by a printing company on the East Coast of the United States. They were having a problem though: their prints were getting ruined. It wasn’t that the machinery was shredding the paper, but that it was becoming misaligned and putting ink in all the wrong places. It all comes down to how the process works and the need for strict control of every step.

The printing process used at the time was a four color process, perhaps similar or even the same as today’s CMYK printing. The paper stock would advance through the machine to receive one color. Then it would be lined up and run through the same or another machine, to receive another color. This would go on until four colors had been applied. Where colors overlapped, you could create things in between. Blue and Red ink combine to make purple, blue and green make yellow, and so on.

This process relied on extreme precision. If the machine was not aligned correctly, the colors would not lay over each other or land in the right places. At first this sounds like a problem with the press, but it isn’t. If they could print on some magical, flexible steel sheet, they wouldn’t have this problem. In day to day practice, an 8.5″ by 11″ piece of paper is pretty much always that size. In printing presses with miles and miles of paper, that is not the case. Paper absorbs water, causing it to swell and change it’s dimensions. It can also dry and shrivel, once again change it’s dimensions. On a single piece of paper, the difference might be measured in millimeters. The offset isn’t a significant issue. Printing presses however, use rolls of paper that are miles long. One millimeter every “page length” adds up. Just a few pages later, the printer is misaligned by inches. It’s spitting out a mess.

Printers could attempt to adjust for these changes, use various registering systems to improve their alignment, but it wasn’t good enough. The paper would easily change size between color applications and from print run to print run. Productivity was lost recalibrating the machinery and precious paper stock had to be trashed everytime errors cropped up.

The Culprit

The problem is that paper will take any water it gets. You don’t have to drop it in a bucket of water or spill anything on it. Paper will take water out of the air: humidity. In a place like the desert with a year-round 0% humidity, this wouldn’t be an issue. In a tropical setting where the humidity is near 100% year round, it’s not an issue either. The paper would absorb all the water it could get from the air and remain at a relatively fixed size.

Philadelphia, New York, and just about the entire North East of the United States doesn’t have such a fixed humidity. Our summers can be so humid, you swear fish will start swimming in the air one day, then the next be quite comfortable in a good breeze. A storm might roll through and suck all the water out of the air with a good cold front, just to saturate the air the next day.

This arrangement just doesn’t work for printing at-scale. A simple 10% change would ruin the printer alignment. We can experience bigger changes than that over a few hours, let alone an actual working day of printing. We couldn’t change the printers or the paper, so we had to change the air. We had to condition it.


A Dehumidifier

The original system wasn’t meant to cool the air. It was meant to dry it. Air would be passed over cold coils, forcing the water to condense and drip away harmlessly. We would call it a dehumidifier today. It just happened to have the secondary effect of making the air really, really cold.

This was initially achieved with ammonia, a piston driven compressor, and even a repurposed insecticide sprayer. Over the years to follow, new designs would replace the original system. Ammonia would be replaced with safer alternatives. The piston would be traded in for a more efficient centrifugal compressor inspired by pumps. The sprayer would disappear entirely from most systems.

The printing industry quickly spread word of the magical device. Printers around the world were chomping at the bit to get at Carrier’s air conditioner. They wanted to solve their printing problems too. It didn’t take long for other industries to get in on it too. Manufacturers, the White House, hotels, department stores and more all wanted a cooling system of their own. The demand was so high that Carrier successfully started his own company, just to develop, manufacture, and sell air conditioners. That company is still around today.


A Legacy

Willis Carrier would live to the ripe old age of 73. He died in October of 1950, having changed the world. It’s hard to find someone who doesn’t have an air conditioner. We build them into our homes. We build them into our cars and trucks. We have them in our offices, schools, and factories. They’re an essential part of our modern life.

Carrier Corporation carries on with Willis’s name and continues to innovate.

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