The two pipes you see at the outdoor unit of a split air conditioner serve different purposes and are essential components of the system. The split air conditioner consists of two main units: the indoor unit and the outdoor unit, which are connected by these two pipes.
- Large Refrigerant Line (Suction Line): The larger pipe is known as the suction line or the refrigerant line. Its primary purpose is to carry the refrigerant from the indoor evaporator coil (located inside your living space) to the outdoor condenser unit. The refrigerant is a chemical responsible for absorbing heat from the indoor air, cooling it down, and then releasing the heat outside.
The process starts at the indoor unit's evaporator coil, where the low-pressure, low-temperature refrigerant absorbs heat from the warm indoor air, turning it into a gas. This gas is then conveyed through the suction line to the outdoor condenser unit.
- Small Refrigerant Line (Liquid Line): The smaller pipe is called the liquid line. Its primary function is to return the high-pressure, high-temperature refrigerant from the outdoor condenser unit back to the indoor evaporator coil. The refrigerant, after releasing heat outside, is now in its liquid state.
The liquid line carries this high-pressure liquid refrigerant back to the indoor unit, where it goes through an expansion valve. This valve reduces the pressure of the refrigerant, causing it to evaporate and turn back into a low-pressure gas. The cycle then repeats as the refrigerant absorbs heat from the indoor air again.
In summary, the two pipes work together to facilitate the continuous cycle of heat exchange and cooling in a split air conditioning system. The larger pipe carries low-pressure gas refrigerant from the indoor unit to the outdoor unit for heat release, while the smaller pipe returns high-pressure liquid refrigerant from the outdoor unit to the indoor unit for cooling. This process allows the air conditioner to cool the indoor space efficiently by transferring heat from inside to outside.