Air conditioning

Air conditioning is a great invention that was created to help people survive or cope with adverse conditions of temperature. A commercial or restaurant kitchen is a great example of a place that needs air conditioning. It is always hot and unbearable for chefs and other people in the kitchen. You can also imagine working in a stuffy office on a hot day and even with the windows open it is still not cool enough for you to work. These two scenarios and others were the reason air conditioning was invented. It helps you remain comfortable even with the adverse weather conditions outside. It is believed to have been started in Egypt where they would plant reeds to encourage the cool breeze to enter inside the houses.

This background led to significant inventions of air conditioners that are now used worldwide. So how does the modern air conditioning work? It has five major parts and almost every type of air conditioner has these parts:

  • Refrigerant
  • Compressor
  • Condenser
  • Expansion Valve
  • Evaporator Coil
  • There are a great variety of air conditioning systems that can be used depending on your preference and the location of where the air conditioner is to be used. These air conditioners include window, portable, ductless and central air conditioning systems. The refrigerant changes state from gas vapor to liquid as it collects heat from your environment and ejects that heat to the outside. Refrigerant is special in that it has a very low boiling point meaning that it changes from a liquid to a vapor at low temperatures. The compressor is the central part of a functioning air conditioner. Refrigerant enters the compressor as a low pressure warm vapor and leaves it as a high pressure hot vapor. From the compressor, hot refrigerant vapor moves to the condenser. Here the high pressure hot refrigerant vapor is cooled by air blowing over finned condensing coils by the condenser fan as it moves through the finned coils. As the refrigerant temperature is lowered it changes state from a hot vapor to a hot liquid at high pressure and moves onto the expansion valve. The expansion valve is also an important part of the air conditioner. As 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. So now we have a low pressure cold liquid mist that moves onto the evaporator coil. The low pressure cold liquid leaving the expansion valve now runs through the evaporator coil located in the plenum of your furnace. Here the hot air of your home blows across the evaporator coil and heats it up while the cold coil cools off the air blowing across it and 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 onto the compressor and exterior condensing unit and the cooling cycles continues.