(first posted 6/1/2017) I’ve never really seen a good, comprehensive history of Automotive Air Conditioning, so I decided to take it upon myself to write one, being somewhat of a scholar on the subject. In this first installment, we will deal with the pre-World War II attempts at automotive A/C, or the pre-modern era as I call it.
The principles of mechanical cooling were understood for centuries, but it wasn’t until Willis Carrier installed his first commercial system in 1902 that air conditioning was born. While it was slow to start, by the 1930’s air conditioning started to become commonplace in stores, movie theaters, and office buildings. With the rise of steel-bodied closed cars in the 1920s, people naturally wanted to bring this experience to their vehicles.
While people have been playing around with ice and evaporative cooling since cars first became enclosed, most historians recognize John Hamman, Jr. as the owner of the first air-conditioned car. The system was custom-built and installed by Kelvinator in Houston, Texas around 1930, as much for the treatment of Mr. Hamman’s severe allergies as for its cooling ability. It was mounted in the back of the car, where the external trunk would normally be, and was powered by its own internal combustion engine.
Other than the photo above, I can’t find much information on Mr. Hamman’s Kelvinator setup. However, the newspaper article below shows a similar system being tested in New York City in 1933. A large compressor running under your feet no doubt canceled out the noise isolation benefits of having the windows up.
While the systems above were one-offs, all the major auto manufacturers were working on their own air conditioning systems in the 1930s. However, several obstacles needed to be overcome before commercially viable automotive air conditioning could become a reality.
First, the systems needed to be reduced in size and complexity so that they would fit within the body of a car, and be powered off the car’s engine, instead of requiring a separate internal combustion engine. This would be accomplished by spreading the components throughout the car, as we shall see.
Second, many of the refrigerants used in early air conditioning system (such as ammonia, chloromethane, propane, and sulfur dioxide) were either toxic, flammable, or both. In either case, these are not desirable properties for a material in an automobile to have in the event of an accident or leak. While less dangerous refrigerants like air and water were experimented with, they are not practical because a phase change is typically not involved in their use, and as a result, they have a low thermodynamic efficiency.
In the 1930s, a joint team from GM and Dupont discovered that by combining carbon tetrachloride with hydrogen fluoride, one could produce Dichlorodifluoromethane, better known as Freon-12. Here was a refrigerant that met or exceeded the efficiency of its more dangerous alternatives, but was (at the time) considered completely harmless. Co-discoverer Thomas Midgley famously gave public demonstrations of this by filling his lungs with Freon, and then blowing out a candle. With the discovery of R-12, the last obstacle to practical automotive air conditioning had been overcome.
While GM clearly had an early lead in automotive AC by developing Freon with Dupont, for reasons I have not been able to ascertain they did not rush to capitalize on it (perhaps it was the Depression). Instead, it was Packard that has the honor of debuting the first “factory” automotive air conditioning system, in August of 1939, on its 1940 Senior models, the 160 and 180. I placed the word factory in quotes because in actuality, the system was not installed at the Packard plant in Detroit, nor was the system even developed by Packard. Instead, vehicles ordered with the $475 option (about $5,000 today) were shipped to Cleveland, Ohio, where Bishop & Babcock performed the installation of their system.
The B&B air conditioning system, unlike modern systems, had components scattered throughout the vehicle, as shown in the diagram above. Like modern systems, the compressor was engine driven and located under the hood, and the condenser was located in front of the radiator. However, the blower and evaporator were located behind the trunk, and the dryer/accumulator were located amidship, on the refrigerant return line from the rear of the car to the front.
Compared to modern systems, the Bishop & Babcock system was primitive. The system discharged cooled air through a single duct in the rear parcel shelf, which meant that back seat passengers would have gotten cold necks, while almost no cool air would have made it to the front of the car. Condensation and dripping in the rear were common problems. There was no fresh air intake, which meant that 100% of the air was recirculated (being pulled in through a nifty looking register in the floor). This would have caused the inside air to get stale, especially if one or more of the occupants were smoking (very likely, given the time).
Packard had a small auxiliary heater core in front of evaporator for a modest amount temperature control, but without a blend door temperature changes would have been slow and modest at best. Otherwise, the only way to control the temperature was to adjust the blower speed or crack open a window. Still, it beat sweating.
The compressor was a two-cylinder inline design (as opposed to the axial arrangement of modern compressors), and looks very much like one you might see on a modern air compressor. Lacking an electromagnetic clutch, the compressor ran continuously whenever the engine was running. The only way to turn it off was to remove the drive belt from the compressor. All the refrigerant lines were copper, which were easily damaged by engine motions and chassis flex.
Owing to the high price (on top of an already expensive car) and limitations above, sales were predictably slow, especially outside of the south. This didn’t stop other auto manufacturers from getting in on the air conditioning business. Cadillac offered a system in 1941 (albeit without the auxiliary heater core), and Chrysler got on board in the abbreviated 1942 model year.
As near as I can tell, all the prewar systems were built and installed by Bishop & Babcock in Cleveland, who apparently did not have an exclusive agreement with any single manufacturer for the technology. The compressor on the Cadillac system pictured below is clearly identical to the one in the 1940 Packard pictured above.
Chrysler offered the system on the 1941 Crown Imperial and supposedly on the 1942 DeSoto, but due to the abbreviated 1942 model year, it is unclear whether any 1942 DeSotos were actually sold with air conditioning. My Google searches came up empty: All I could find the ad pictured below. However, it was clearly the same B&B system used by Packard and Cadillac.
World War II quickly stopped any further development on the B&B air conditioning system (or any other one, for that matter). So what happened after the war? The answer will likely surprise you. Stay tuned for the answer in Part 2.