Abstract： An air conditioner is basically a refrigerator without the insulated box. It uses the evaporation of a refrigerant, like Freon, to provide cooling. The mechanics of the Freon evaporation cycle are the same in a refrigerator as in an air conditioner.24169
Keywords： water towers 、weather-resistant、 compressor、energy conservation
When the temperature outside begins to climb, many people seek the cool comfort of indoor air conditioning. Like water towers and power lines, air conditioners are one of those things that we see every day but seldom pay much attention to. Wouldn't it be nice to know how these indispensable machines work their magic? In this article, we will examine air conditioners -- from small to huge -- so you know more about what you're seeing!
The Many Faces of Cool
Air conditioners come in various sizes, cooling capacities and prices. One type that we see all the time is the window air conditioner.
Window air conditioners are an easy and economical way to cool a small area. Most people who live in suburban areas usually have one of these in their backyard:
If you live in an apartment complex, this is probably a familiar sight: Most businesses and office buildings have condensing units on their roofs, and as you fly into any airport you notice that warehouses and malls may have 10 or 20 condensing units hidden on their roofs:
And then if you go around back at many hospitals, universities and office complexes, you find large cooling towers that are connected to the air conditioning system:
Even though each of these machines has a pretty distinct look, they all work on the same principles. Let's take a closer look.
The Basic Idea
An air conditioner is basically a refrigerator without the insulated box. It uses the evaporation of a refrigerant, like Freon, to provide cooling. The mechanics of the Freon evaporation cycle are the same in a refrigerator as in an air conditioner. According to the Merriam-Webster Dictionary Online, the term Freon is generically "used for any of various conditioner. According to the Merriam-Webster Dictionary Online, the term Freon is generically "used for any of various nonflammable fluorocarbons used as refrigerants and as propellants for aerosols."
This is how the evaporation cycle in an air conditioner works (See How Refrigerators Work for complete details on this cycle):
1.The compressor compresses cool Freon gas, causing it to become hot, high-pressure Freon gas (red in the diagram above).
2.This hot gas runs through a set of coils so it can dissipate its heat, and it condenses into a liquid.
3.The Freon liquid runs through an expansion valve, and in the process it evaporates to become cold, low-pressure Freon gas (light blue in the diagram above).
4.This cold gas runs through a set of coils that allow the gas to absorb heat and cool down the air inside the building.
Mixed in with the Freon is a small amount of a light weight oil. This oil lubricates the compressor.
Window Units
A window air conditioner unit implements a complete air conditioner in a small space. The units are made small enough to fit into a standard window frame. You close the window down on the unit, plug the unit in and turn it on to get cool air. If you take the cover off of an unplugged window unit, you will find that it contains:
A compressor
An expansion valve
A hot coil (on the outside)
A chilled coil (on the inside)
A control unit
The fans blow air over the coils to improve their ability to dissipate heat (to the outside air) and cold (to the room being cooled).
BTU and EER
Most air conditioners have their capacity rated in British thermal units (BTU). Generally speaking, a BTU is the amount of heat required to raise the temperature of one pound (0.45 kg) of water 1 degree Fahrenheit (0.56 degrees Celsius). Specifically, 1 BTU equals 1,055 joules. In heating and cooling terms, 1 "ton" equals 12,000 BTU. 空调节能技术的研究英文文献和中文翻译:http://www.751com.cn/fanyi/lunwen_17550.html