Three-quarters of all homes within the United States have air conditioners. Air conditioners consume about 6 percent of the electricity generated by the United States, at an annual cost of $29 billion for homeowners. This means that around 117 million tonnes of carbon dioxide is released into the air every year. Take a look at the Energy Saver 101 infographic on cooling at home to find out more about air conditioners.
Air conditioners use the same principles of operation and fundamental components as your refrigerator at home. Refrigerators utilize energy (usually electric power) to transmit heat away from the cold interior of the fridge to the warmer surroundings of your home. Similarly, an air conditioner uses power to move heat away from the inside of your house to the outdoors.
The air conditioner can cool your home by using the cold indoor coil known as the evaporator. The condenser, a warm outdoor coil lets the heat it collects outside. The condenser and evaporator coils consist of a serpentine tube that is surrounded by fins of aluminum. The tubing is typically comprised of copper.
A pump, also known as the compressor, is used to move the heating transfer liquid (or refrigerant) between the condenser and the evaporator. The compressor forces refrigerant to move through the circuit of fins and tubing inside the coils.
The refrigerant liquid evaporates inside the evaporator coil and draws heat from the indoor atmosphere cooling down your house. The refrigerant’s hot gas is pumped outside to the condenser, where it changes to a liquid releasing its heat to outside air moving through the condenser’s tubing made of metal and fins.
In the latter half of the 20th century, almost all air conditioners utilized chlorofluorocarbons (CFCs) as refrigerants however, since these chemical compounds harm the Earth’s Ozone layer CFC manufacturing stopped across the United States in 1995. The majority of air conditioning systems today use halogenated chlorofluorocarbons (HCFCs) as refrigerants. The most recent HCFC known as the HCFC-22 (also known as R-22) was first slated to be phased out by 2010 and will be completely removed in 2020. However, HCFC-22 is expected to remain available for a long time when it is taken out and repurposed from older systems that have been taken out of service. As refrigerants are eliminated, ozone-safe hydrofluorocarbons (HFCs) are likely to be the dominant choice, as also other refrigerants like ammonia.