Air Conditioners: How They Function

Air Conditioners: How They Function

By: Tammy Olson

January 1, 2006

Physics 102

William Beston

Air Conditioners: How They Function

Have you ever wondered how air conditioners work? Well, you are in luck. After you read this paper, you will have a sure idea of how an air conditioner functions. Did you know that the first person to coin the phrase "air conditioning" was Stuart W. Cramer? But, Willis Carrier is the inventor who patented his invention calling it an "Apparatus for Treating Air." That's where it all started. The year was 1906. I will take you from then to now. I will explain how an air conditioner functions and the components that make up the system (Timeline of, pg.1).

It was 1917 when the first documented theater, New Empire Theatre in Montgomery Alabama used refrigeration. This started the use of air conditioning, a/c, in public buildings. The Chamber of the House of Representatives, The Senate, The White House, The Executive Office Building, and the Department of Commerce, were all air conditioned following the Alabama Theatre. Then, a/c took a halt until the end of World War II. In 1946, the demand climbed. In 1953, the demand was exceeding the supply greatly. Manufacturers could not make enough to keep the population satisfied. Many people were realizing the effects they experienced through the comfort of a/c. In the summer, families seemed to sleep longer, enjoy their food more, and have more leisure time. Air conditioning helped science advance greatly. With the life support and cooling systems Neil Armstrong and Buzz Aldrin walked on the moon in space suits (Timeline of, pg.2).

Now you are probably asking yourself, how does it work? That's a good question. An air conditioner literally includes the cooling and heating of air, cleaning it and controlling its moisture level. An air conditioner actually transfers heat from the inside of a building, where it is not wanted to the outside. It uses the evaporation of a refrigerant, like Freon, to provide cooling. Freon is a chemical compound consisting of chlorofluorocarbons (Ostdiek, & Bord, chap. 8, pg.323). Freon is forced to change phases from gas to liquid, liquid to gas, to complete the process. The compressor cools the Freon, to provide a hot, high-pressure Freon gas. The hot gas runs through coils so it can dissipate its heat, and it condenses into a liquid. The Freon liquid then is forced through an expansion valve. When it does this, it evaporates to become cold, low-pressure Freon gas. The cold gas, Freon runs through a set of coils that allow the gas to absorb heat and cool down the air inside the building. The following diagram displays this action (How Stuff Works, pg.1):

DIAGRAM OF A TYPICAL AIR CONDITIONER

A: Expansion Valve B: Compressor

Diagram compliments of: (How Stuff Works, pg. 1)

The central air unit, or split-system unit, are common in residential areas such as your home. A split-system fits its name perfectly because it splits the hot side and the cold side of the air conditioner. The hot side, known as the condensing unit, is located outside the house. The unit consists of a long, spiral coil shaped like a cylinder. Inside the cylinder is a fan. This fan blows air through the coil along with a compressor. The cold side, known as the air handler or furnace, consists of an expansion valve and the cold coil. The air handler blows air through the coil, and routes the air throughout the building using a series of ducts. A thermostat, which is used to control the temperature in the house, is the brain of the system. It tells the system when to function to provide comfort in your home. There are filters placed in the system to clean the air of dust and particles (How Stuff Works, pg.1).

The following diagram shows a split-system air conditioner:

Diagram compliments of: (How an Air Conditioner Works, pg. 1)

A split-system air conditioning unit has its limits. Whenever the building is too large, the spit-system