Air Conditioning: A Crash Course

Air Conditioning: A Crash Course

Posted by
Ed Miller on Fri, May 20, 2016

inside an A/C unit










Sure, it was possible to live in Northeast Florida before the invention of home air conditioning units, but it was very uncomfortable. An A/C unit in Florida is like a furnace in colder areas: you don’t really want to live without them. If you own a home in the Jacksonville area, then you will want to understand the basics of how air conditioning works. This way you are educated if you ever have to purchase a new a/c unit or repair an existing one. So let’s look at what goes on inside that big magic box in the backyard.

The Basics

The basic principle is that when liquids evaporate and turn into gases, they absorb heat. Your A/C unit is basically a closed set of coiled pipes with special chemical refrigerants running through them. These refrigerants evaporate at room temperatures.

Cooling By Evaporation

The coils in the part of the unit inside your home are called evaporation coils. Ducts and fans force air inside your home over these coils. The refrigerants evaporate in the coils, cooling the air. This cooler air is blown back into your house creating a comfortable living environment for you and your family.

So inside your home, the refrigerant go from liquid to gas in the coils. The gaseous refrigerants flow through the coils to the box outside your home where they are converted back to a liquid in a process called condensation. This second set of coils outside your home is called condensation coils.

Closing the Loop with Condensation

The refrigerant chemicals in the coils evaporate naturally at room temperatures, but they need to be forced to condense back into a liquid. This is done by increasing the pressure of the gas in the coils. The machine that does this is called a compressor. Gasses at high pressures will condense back into liquids.

The compressed gas releases energy to the outside environment, cooling the refrigerant. This cool liquid refrigerant flows through the coils back inside your house into the evaporation part of the system. There is an expansion value at this point in the system to regulate the flow of liquid refrigerant into the evaporator coils.

Types of Units

Window air conditioners and units installed directly into the wall house both the evaporator and condensation coils in the same unit. In split A/C systems, the condenser coils and compressor are housed in a unit outside of the home. This reduces noise inside the home and increases the capacity of the entire system.

System Size and Efficiency

A/C units have a BTU rating for their capacity. BTU stands for a “British Thermal Unit” and represents the amount of heat necessary to increase the temperature of one pound of water by one degree Fahrenheit. A house that is 2,000 square feet might require a 60,000 BTU system. The EER of the system is the energy efficiency rating. This tells you how much energy in Watts the system will require. Systems with higher efficiency ratings often cost more, but the increased efficiency will result in reduced operating costs. So eventually the more expensive and efficient systems will pay for themselves.

Now that you know how an A/C unit works, you will understand what your HVAC contractor is doing when you install or repair your own unit. At Snyder, our expert professionals have served the Jacksonville area since 1970. We can help you put in a new A/C system, upgrade to a bigger or more efficient system or make repairs to an existing unit. Contact us for more information.

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