Air Conditioning Systems - Primitive to Sophisticated

The Romans had water therapy. They knew the pleasures of sitting by a cool fountain, but it was the ancient Egyptians who started refining the first air conditioning system.

To the Egyptians, the Nile River was the River of Life in many ways. Not only did it provide water for drinking and bathing, but it made farming possible in an otherwise arid landscape. Besides that, the Nile provided water for the first evaporative cooling on a large scale.

For eons, folks knew that putting water inside a semi-porous container, like an unglazed clay pot, resulted in a cool drink because of evaporation cooling. The Egyptians kicked it up a notch when they constructed parapets over which cascaded sheets of water. Slaves equipped with enormous fans stood nearby and kept the air circulating over the moving water. The result: evaporation cooling.

Several ancient cultures also used "wet mats." We know that Egyptians, Romans, and Greeks all made use of wet mats to cool the air inside homes and other buildings. When a thick, damp cloth was hung over doors and/or windows, the air movement effectively promoted evaporation cooling and could reduce indoor temperature down to as low as about 66° Fahrenheit. The Egyptians even figured out how to make ice!

In the early days of air conditioning, especially in the arid parts of the United States, evaporative cooling was still in broad scale use. The boxy, adobe-style houses of the Southwest often have a roof structure designed to support the considerable weight of a shallow pond. When the roof is flooded, fans blow dry air across the liquid, speeding up evaporation. The cooled air is then routed through the building, a welcome relief in the hot summer months. These coolers, sometimes called "swamp coolers" are economical to operate and are still in use in some areas.

Modern air conditioning systems no longer rely on water for evaporation cooling. Gases like Freon or Puron are the modern refrigerants that lower air temperature. The actual air conditioning unit is usually placed outside the building because it is a harmless and more efficient way to get rid of the inside heat (into the atmosphere).

An important function of today's AC system is to reduce the humidity levels inside the structure. Keeping the humidity levels low (in the area of 30%) reduces problems with mold and mildew, and helps to alleviate serious health problems for people who suffer with allergies. Also, dust mites find it difficult to survive in low humidity conditions.

When an air conditioning unit is up and running, it works to maintain a pressure level throughout the entire structure. To help the unit work efficiently, doors and windows need to be closed so that the pressure can remain as constant as possible. For spot cooling, consider adding a small fan to move the air right where you need to up the comfort level.