As we saw in the last article, the HVAC industry came of age in 1906 when a textile engineer, Stuart Cramer, first used the term air-conditioning. The developments in HVAC still had a long way to go however. In fact, at this point in time, the first residential unit that was installed in 1914 needed a room of its own. It was over two metres tall, two metres wide and over 6 metres long. The cost was between $10,000 and $50,000 which in today’s money is between $120,000 and $600,000. Way beyond what was affordable for the public.
In 1920, Carrier created a smaller version of his cooling unit. This development meant that department stores, commercial buildings, and railroad cars could be air conditioned. Then in 1922 the company invented the first centrifugal chiller. This well-designed unit was installed in theatres in Los Angeles. Air was pumped through higher vents, which resulted in more equally distributed cooling. This was also installed in New York’s Rivoli Theater in 1925. Although it was more reliable and less costly than previous systems, it was still too big and expensive to use wide scale.
Frigidaire and General Electric both appeared on the HVAC landscape within a decade of Carrier’s big achievement. In 1929, Frigidaire debuted a split-system room cooler that was shaped like a radio cabinet. Although it was small enough for homes, it was also very heavy requiring its own condenser.
A year later, General Electric patented 32 prototypes for improved self-contained room coolers. General Electric created a “self-contained room cooler” which led to the first modern window air conditioning unit which was introduced to the market in 1931. It was extremely expensive to purchase and install and was incredibly loud to operate.
Air conditioning units remained noisy until the late 1950s when rotary compressors were developed and by the 1960s most homes had some sort of HVAC system. Also, around 1931, General Motors synthesized CFC (chlorofluorocarbon) coolants, the world’s first non-flammable refrigerants. Although they helped with cooling, CFC coolants were later linked to ozone depletion and phased out in the 1990s.
Heating in the Early 20th Century
On the heating front, 1905 saw manufacturers establishing the Federal Furnace League to bring heating systems into the position they deserved. Their efforts culminated in the National Warm Air Heating and Ventilation Association in 1914. This association later produced a series of manuals for appropriate sizing and installation of heating systems. Then in 1918, the Electrol was introduced as the first oil burner with an electric ignition.
Honeywell designed the first controls exclusively for oil burners in 1924. In 1935, the first forced-air furnace was introduced and used an electric fan to distribute coal-heated air through the home’s ducts; gas- and oil-fired versions followed. Speaking of which, the 20th century brought many scientific breakthroughs of benefit to the HVAC industry. Nikola Tesla developed alternating electrical current motors which made oscillating fans possible.
Benefits of Airconditioning
It was realised that air conditioning wasn’t simply a matter of being comfortable, a 1938 study of Detroit Edison workers showed that productivity increased by 51 percent after comfort cooling was installed in the factory. Furthermore, air conditioning also saves lives.
Between 1960 and 2004, heat-related deaths in the United States were 80 percent lower than they had been in the previous 59 years. Air conditioning played a major role in reducing those numbers.
In 1944, four U.S. patents were issued for the Carrier Conduit Weathermaster system, which made efficient air-conditioning of skyscrapers possible. Since 1947, AC units have become more compact and cheaper. In that year, 43,000 systems were in use. By the 1960s, most new homes in the United States were built with central air conditioning. By then, electric air conditioner window units were affordable and had come down in price from the early days.
In the 1970s central air conditioning became commonplace. As years passed, air conditioning units became more energy-efficient to comply with modern environmental laws.
Modern and Future Developments in HVAC
Of course, the HVAC industry never stops innovating. Newer, more energy efficient systems are constantly being developed and only time will tell what new developments will be next in the HVAC industry.
HVAC systems have changed the way buildings are designed, built, and occupied. It made the building of larger, taller structures possible.
The mechanical aspects of air-conditioning developed rapidly in the first half of the 20th century, but since then developments in electronics have moved rapidly. Computers have given manufacturers ways to design equipment and do thermal modelling in buildings to aid design and determine heating and cooling loads.
Electronics has made HVAC systems smarter, smaller, and more efficient. They have reshaped how the systems are installed, maintained and operated. We now have electric motors and drives, microprocessors, and increased automation. The smart building has arrived.
Where to from here? The most important aspects of HVAC in the future are probably going to be energy sustainability. Doing more with less energy and green sources. AI will probably play an important part in the smart building. Imagine a system that learns when you get up from sensors that show your sleep patterns then learns your movements to control the environment in the rooms where you are. Science fiction meets reality.
No matter where the HVAC industry goes, it will be an exciting journey and no one can imagine what it will look like in another hundred years.
