In air conditioning systems, the two copper pipes you see are part of the refrigerant circuit and play important roles in the cooling process. They are typically referred to as the "suction line" and the "liquid line."
Suction Line: The larger copper pipe is the suction line, also known as the low-pressure line or the evaporator line. It carries refrigerant in its gaseous state from the evaporator coil, located in the indoor unit of the air conditioner, to the compressor, which is usually situated in the outdoor unit. The refrigerant absorbs heat from the indoor air as it passes through the evaporator coil, converting it from a low-pressure gas to a low-pressure, cool vapor.
Liquid Line: The smaller copper pipe is the liquid line, also called the high-pressure line or the condenser line. It transports refrigerant in its liquid state from the outdoor condenser coil to the indoor evaporator coil. The refrigerant in this line is under high pressure, having been compressed by the compressor in the outdoor unit. As it travels through the condenser coil, the refrigerant releases heat to the outdoor air and condenses into a high-pressure liquid.
These two copper pipes, along with the refrigerant circuit, create a closed loop through which the refrigerant cycles between the indoor and outdoor units. This cycle allows for the transfer of heat from the indoor space to the outdoor environment, resulting in the cooling effect provided by air conditioners.
It's worth noting that the copper pipes are insulated to prevent condensation and maintain the efficiency of the cooling process. Insulation helps minimize heat gain or loss along the pipes, ensuring that the refrigerant remains at the desired temperature and pressure levels throughout the system.