• Avoid Problems with HVAC
• Improving Indoor Air Quality
• Decrease Your Energy Bill While Cooling Your Home
• Energy & Cost Efficient Changes to Your HVAC
• Purchasing An Energy Efficient HVAC System
• Air Conditioning – Definition and History
• How Air Conditioners Work
• HVAC – Heating, Ventilation, and AC
• Alen Corporation - History and Products
• Air Fresheners Don't Freshen
• Make Your Home Safe with Better Ventilation
• FEMA Trailer Residents Fighting Mold
• Humid Areas at High Risk for Mold
• Relieve Stress By Removing Clutter
• Toxicity in Office Affects Indoor Air Quality
• Using Candles Safely
• Wet Weather Breeds Mold

Air Conditioning – Definition and History

Air Conditioning refers to the modification of indoor air for comfort. Although most consumers recognize “air conditioning” as a means to decrease the overall temperature of a room, heating, cooling, dehumidifying, ventilating, and disinfecting all fit into this broad term. In general, though, “air conditioners” are sold for the purpose of cooling the air and controlling the humidity in a room.

Where some air conditioners depend on coolant liquids (like those found in refrigeration units), others use evaporation to help cool the air. The energy transfer of the evaporation process allows water to use the heat from a building or air to evaporate, resulting in a decrease in temperature of the room. This process has been used by civilizations for centuries, many of which built water tunnels through their walls to facilitate heat transfer and evaporation.

The concept of using a liquid other than water to cool the air first came about in 1820 when Michael Faraday used ammonia to cool the air. Some progress was made over the next 82 years but leaped into modern air conditioners when Willis Carrier invented the first electrical air conditioner in 1902. Although Carrier continued to make progress with controlling temperature and humidity, another inventor, Stuart Cramer, developed industrial methods of evaporative cooling to decrease air temperature. Freon was later developed as a major coolant liquid for air conditioners, but it was later found to have detrimental effects on the environment. Alternative cooling liquids have been developed and Freon will be phased out of air conditioners by 2020.

Modern homes and facilities use air conditioners for both human comfort and processes. Residential homes and offices regulate the inside temperature for the benefit of the individuals inside. In these types of buildings, air temperature and humidity control are regulated primarily for the comfort of the residents or workers. Some companies and industries, however, require temperature regulations in order to facilitate processes. In these instances, the climate requirements of the process of procedure have priority over the comfort of the workers. If the temperature or humidity is not properly controlled in these areas, the process cannot by completed. These rooms include:
 

• Cleanrooms
• Laboratories
• Operation Rooms in Hospitals
• Textile Factories
• Nuclear Facilities
• Mines
• Food processing facilities

Some air conditioners are set up for the sole purpose of controlling the humidity. These units are usually referred to as humidifiers or dehumidifiers depending on the device. Humidifiers usually evaporate water into the air and can be used to help alleviate certain respiratory problems, especially in young children. Dehumidifiers, on the other hand, use cooling coils to cause water to condense out of the air and decrease the relative humidity of a room.

Air conditioners have been used for years to help improve health conditions for thousands of hospital patients in regulated environments as well as allergy and asthma sufferers within their homes. Cooling centers have been used to help keep the elderly comfortable during hot periods of the year.

Air conditioners can help save lives during heat waves, but improperly maintained units can cause serious health problems. If a unit is not properly maintained or drained, it can build up moisture, causing mold and other infectious organisms to grow and spread within the home.

Although most homeowners and businesses use either window air conditioners or central cooling systems, portable air conditioners are also available. These room air conditioners can be moved from area to area depending on the needs of the consumer. They come in three variations: split, hose and evaporative.

• Split units use a flexible hose or pipe to run cool air from a permanent outside unit to the portable one.
• Hose units dehumidify air while cooling it but, like the split versions, use a hose or connective tube to vent through the duct work.
• Evaporative portable units use water evaporation to cool the air and do not require any connections to existing vents or other units. In this respect, evaporative portable air conditioners have more flexibility in terms of portability.

The two internationally recognized professional air conditioning organizations are the American Society of Heating, Refrigerating, and Air-Conditioning Engineers and the Australian Institute of Refrigeration Air Conditioning and Heating. Both of these organizations provide standards and guidelines for their respective industries within their countries.