HowItWorks.net

What would we do without air conditioning? This is one appliance that has really changed the quality of our lives at home, work and play, but how exactly does air conditioning work?

In order to understand how air conditioning works; it is important to understand the principle of moving heat. Simply put, an air conditioner does not cool the air; it just removes the heat from a confined space. When two objects of different temperatures are placed next to each other, there will be a transfer and flow of heat from the warmer object to the cooler one. This is the law of entropy where all things will eventually become the same temperature. The rate of time the temperatures will become the same varies depending upon the difference between the two temperatures. If there is a huge difference in temperature, there will be a large period of time it takes for the temperature to equalize. This lessens as the temperatures get closer together.

Air Conditioners – Cool and Dehumidify

Air conditioners cool and filter air as well as dehumidify the air of a room. You can think of a refrigerator the same way as an air conditioner. The refrigerator cools a small space inside a box and the air conditioning unit cools whatever environment you have. There are basically two types of air conditioners; central air conditioners cool the total home and are part of the heating system and room air conditioners that will cool smaller areas. Air conditioners are powered by electricity. They use a refrigerant called Freon that transfers heat from the indoors out. The Freon gets to the compressor as a cool, low pressure gas and leaves the compressor as a hot high pressure gas. It then circulates through closed-circuit copper tubes that run between an outdoor coil called a condenser, and an indoor coil that is an evaporator. The Freon changes from liquid to gas and back to liquid as the temperature and pressure changes. When the Freon circulates through the evaporator it absorbs heat from the house. The heat is then carried by the Freon outside through the condenser.

If you look outside the home, the big appliance of a central air conditioning unit is what carries the heat outside the home into the outdoors to cool. It acts like a car radiator and allows hot air to be dissipated quickly. This is a constant process that circulates over and over again inside the air conditioner keeping the room cool and comfortable, depending on what temperature the thermostat is set on. The evaporator has a fan that circulates the air. This air is lighter than cold air so the heat rises. The cool air is blown through the house through ducts which are usually located at the floor level.

Dehumidifiers can be installed as part of the system, or portable dehumidification may be required in some homes.

The air conditioning system for a building also removes moisture from the air to provide comfort and mold and mildew control. Warm moist air is blown through a cooling coil. The air will be cooled below the dew point temperature. Relative humidity is the amount of moisture in the air relative to the moisture that the air can hold. As air is cooled, it cannot hold moisture. Once the air is cooled below the dew point, it collects the moisture in a drain pan out or releases it out of the system. The building will then have cooler, drier air. When the air is a lower dew point, this is called the exit dew point. Most conditioning systems need help at removing excess moisture; especially in very humid climates. Dehumidifiers can be installed as part of the system, or portable dehumidification may be required in some homes. If dehumidifiers are installed; they use a form of reheating and potential cooling is wasted. It is important to have the correct size of air conditioning installed in a home. If the cooling unit is too big or too small for the size of building; it will become very inefficient. If a unit is too small; it will run longer because it cannot satisfy the thermostat. It will remove more moisture at this time, but the temperature will also be higher. If the fan speed is reduced on the system; this causes the coil temperature to drop allowing cooling to occur, but this lowers the dew point exit air and the air conditioning system is less efficient.

If shopping for a new air conditioning unit; there are some things to consider for proper efficiency. What actually suits your needs? Is the unit a central air conditioning system or a room air conditioner? Central systems cost more to run and should be included in the overall utility budget. Change the air filters in any system often as a dirty filter also reduces the efficiency and requires more energy to run. Air conditioning has become a necessity in our lives from industry to personal use. It makes our lives better from the moment we get up from a comfortable sleep on a hot summer night. Understanding how air conditioning works provides us with money saving understanding when it comes to operation and repairs.