Understanding Your Air Conditioning

To most of us, air conditioning systems are a confusing, complicated system of wires. motors and air ducts. But they are easily understood if your know how all the parts work. Most of us in Texas have a central air conditioning system, which is the best cooling solution for our homes. It is the quietest, best performing and most comfortable type of system. The only real problem is that the system must be sized properly. If it is too large it will not perform well and will not adequately dehumidify and it may short cycle.

First, we need to understand the individual parts of  our air conditioning system and some common terms used.

Air Handler – The part of the system that moves heated or cooled air throughout the ductwork.

Btu – British thermal unit. The amount of heat required to raise the temperature of one pound of water (about one pint) by one degree F. The Btu measurement is also used to describe how much energy and air conditioning unit uses.

Compressor –  A pump that pressurizes refrigerant

Condenser – Facilitates heat transfer

Evaporator Coil – The portion of a heat pump or central air conditioning system that is located in the home and functions as the heat transfer point for warming or cooling indoor air.

Expansion Valve – regulates refrigerant flow into the evaporator

Outdoor Coil/Condensing Unit – The portion of a heat pump or central air conditioning system that is located outside the home and functions as a heat transfer point for collecting heat from and dispelling heat to the outside air.

Refrigerant – Contained within the coils of an air conditioner, these liquid agents cool and dehumidify indoor air.

SEER – Seasonal Energy Efficiency Ratio. A measure of an air conditioner’s cooling efficiency. The higher the SEER, the more efficient the product. The government’s established minimum SEER rating for air conditioners is 10.

Short Cycle – . The compressor constantly shuts on and off. It can be caused by a faulty or obstructed thermostat, leaking refrigerant, icy coils or an HVAC system that is too big for the building in which it is installed.

Split System – A heat pump or central air conditioning system with components located both inside and outside the home. The most common design for home use.

Central air conditioning systems are made up of two units, the condensing unit and the evaporative unit, connected by refrigerant tubing. The condensing unit is the large, boxy unit outside the house. It contains the compressor, condensing coils and condensing fan. The evaporation unit typically sits in the attic assembly of your furnace so the air conditioning can use the same ductwork as your heating system. The evaporative unit consists of the evaporator coil and expansion valve.

The refrigerant is pumped through out the air conditioner’s system. It changes state from gas vapor to liquid as it collects heat from your house and rejects that heat to the outside.  The compressor pumps the refrigerant through all the refrigeration components in a big loop. Refrigerant enters the compressor  at a low pressure as warm vapor and leaves as a high pressure hot vapor. From the compressor, the hot refrigerant vapor moves to the condenser.  In the condenser, the hot refrigerant vapor is cooled by air blowing over finned condensing coils by the condenser fan as it moves through the coils. As the refrigerant cools, it changes state from a hot vapor to a hot liquid at a high pressure. Then it moves onto the expansion valve. The hot liquid refrigerant passes through a tiny opening at high pressure in the valve on one side, it emerges as a cool low pressure mist on the other side because as a gas expands, it cools.

The low pressure cold liquid leaving the expansion valve now runs through the evaporator coil located in the attic unit of your furnace. The hot air from the house blows across the evaporator coil and heats up the coil removing the heat from the air. The cooled air blows back into your home. As the refrigerant heats up, it boils and changes from a cold liquid and evaporates into a warm vapor. From there it moves back outside to the compressor and exterior condensing unit and the cycle continues.

It is possible that you may have a split or ductless air conditioner. The split or ductless system is sometimes called a “packaged terminal air conditioner” (PTAC). Occasionally, they may be used in a home, but more often you find them in hotels, motels and apartments. The principles are the same as central air conditioning, but it has much smaller units. The split system breaks the air conditioning system into two packages or terminal units and refrigerant tubing passes through the wall connecting both package units. One terminal package is the condensing unit located on the exterior and includes the compressor, condenser and condenser fan. The other terminal package is the evaporative unit located on the interior and handles air cooling and distribution. The internal evaporative unit includes the fan, expansion valve and evaporator coil.

If you’re having a air conditioning problem, you should call your certified HVAC repair company. Their certified technicians can explain the differences between systems and product types and make the necessary repairs. Ask about discounts or rebates from the manufacturers. Your certified HVAC technician may also have additional suggestions and may have specials on equipment or other services. Many also have service plans, like Berkeys BAM Plan, that can help save you money on service calls and provide annual tune-ups.

You can call Berkeys Air Conditioning & Plumbing 24/7 at (817) 481-5869 or visit www.Berkeys.com for questions and scheduling information or on Facebook at www.Facebook.com/Berkeys.